@webarticle {16161,
	title = {Role of apyrase in salvaging of phosphate from extracellular nucleotides and in regulating phosphate uptake in Arabidopsis. },
	journal = {Preprint of article submitted},
	year = {Submitted},
	abstract = {
	Apyrases are NTPDases that remove the terminal phosphate from NTPs and NDPs, but not from NMPs. They have conserved structures and functions in yeast, plants and animals. Among the most studied APYs in plants are those in Arabidopsis (AtAPYs) and peas (PsAPYs), both of which have been shown to play major roles in regulating plant growth and development. Valuable insights on their functional roles have been gained by transgenically altering their transcript abundance, either by constitutively expressing them or by their suppression. This review focuses on studies of transgenic lines of yeast and multiple different plants that revealed insights on the growth-altering functions of plant apyrases in different organisms. APY expression can also be inhibited post-translationally by chemically blocking its enzymatic activity, so this review also briefly covers studies that used inhibitors to suppress APY activity in plants and fungi.

},
	author = {Slocum, R D and Wang, H and Tomasevich, A. and Clark, Greg and Roux, Stanley J}
}
@article {13123,
	title = {A pan-protein compex map reveals deep conservation and novel assemblies},
	journal = {Cell},
	volume = {181},
	year = {2020},
	pages = {460-474},
	abstract = {Plants are foundational for global ecological and economic systems, but most plant proteins remain uncharacterized. Protein interaction networks often suggest protein functions and open new avenues to characterize genes and proteins. We therefore systematically determined protein complexes from 13 plant species of scientific and agricultural importance, greatly expanding the known repertoire of stable protein complexes in plants. By using co-fractionation mass spectrometry, we recovered known complexes, confirmed complexes predicted to occur in plants, and identified previously unknown interactions conserved over 1.1 billion years of green plant evolution. Several novel complexes are involved in\&nbsp;vernalization and pathogen defense, traits critical for agriculture. We also observed plant analogs of\&nbsp;animal complexes with distinct molecular assemblies, including a megadalton-scale tRNA multi-synthetase\&nbsp;complex. The resulting map offers a cross-species\&nbsp;view of conserved, stable protein assemblies shared across plant cells and provides a mechanistic, biochemical framework for interpreting plant genetics and mutant phenotypes.},
	url = {https://doi.org/10.1016/j.cell.2020.02.049},
	author = {McWhite, C and Papoulas, O and Drew, K and Cox, R and June, V and Dong, R and Kwon, T and Wan, C and Salmi, M and Roux, S J and Browning, K and Ronald, P and Marcotte, E}
}
@article {13122,
	title = {Ectopic expression of a pea apyrase enhances root system architecture and drought survival in Arabidopsis and soybean},
	journal = {Plant Cell and Environment},
	volume = {42},
	year = {2019},
	pages = {337-353},
	abstract = {Ectoapyrases (ecto-NTPDases) function to decrease levels of extracellular ATP and ADP in animals and plants. Prior studies showed that ectopic expression of a pea ectoapyrase, psNTP9, enhanced growth in Arabidopsis seedlings and that the overexpression of the two Arabidopsis apyrases most closely related to psNTP9 enhanced auxin transport and growth in Arabidopsis. These results predicted that ectopic expression of psNTP9 could promote a more extensive root system architecture (RSA) in Arabidopsis. We confirmed that transgenic Arabidopsis seedlings had longer primary roots, more lateral roots, and more and longer root hairs than wild-type plants. Because RSA influences water uptake, we tested whether the transgenic plants could tolerate osmotic stress and water deprivation better than wild-type plants, and we confirmed these properties. Transcriptomic analyses revealed gene expression changes in the transgenic plants that helped account for their enhanced RSA and improved drought tolerance. The effects of psNTP9 were not restricted to Arabidopsis, because its expression in soybeans improved the RSA, growth, and seed yield of this crop and supported higher survival in response to drought. Our results indicate that in both Arabidopsis and soybeans, the constitutive expression of psNTP9 results in a more extensive RSA and improved survival in drought stress conditions.},
	url = {DOI: 10.1111/pce.13425},
	author = {Veerappa, R and Slocum, R D and Siegenthaler, A and Wang, J and Roux, S J}
}
@article {13121,
	title = {Role of Ca2+ in mediating plant responses to extracellular ATP and ADP},
	journal = {International Journal of Molecular Sciences},
	volume = {19},
	year = {2018},
	abstract = {Among the most recently discovered chemical regulators of plant growth and development are extracellular nucleotides, especially extracellular ATP (eATP) and extracellular ADP (eADP). Plant cells release ATP into their extracellular matrix under a variety of different circumstances, and this eATP can then function as an agonist that binds to a specific receptor and induces signaling changes, the earliest of which is an increase in the concentration of cytosolic calcium ([Ca2+]cyt). This initial change is then amplified into downstream-signaling changes that include increased levels of reactive oxygen species and nitric oxide, which ultimately lead to major changes in the growth rate, defense responses, and leaf stomatal apertures of plants. This review presents and discusses the evidence that links receptor activation to increased [Ca2+]cyt\&nbsp;and, ultimately, to growth and diverse adaptive changes in plant development. It also discusses the evidence that increased [Ca2+]cyt\&nbsp;also enhances the activity of apyrase (nucleoside triphosphate diphosphohydrolase) enzymes that function in multiple subcellular locales to hydrolyze ATP and ADP, and thus limit or terminate the effects of these potent regulators.},
	url = {doi: 10.3390/ijms19113590},
	author = {Clark, G and Roux, S J}
}
@article {13120,
	title = {ANN1 and ANN2 function in post-phloem sugar transport in root tips to affect primary root growth.},
	journal = {Plant Physiology},
	volume = {178},
	year = {2018},
	pages = {390-401},
	abstract = {
	Annexins are a multigene family of calcium-dependent membrane-binding proteins that play important roles in plant cell signaling. Annexins are multifunctional proteins, and their function in plants is not comprehensively understood. Arabidopsis (Arabidopsis thaliana) annexins ANN1 and ANN2 are 64\% identical in their primary structure, and both are highly expressed in



	seedlings. Here, we showed that ann-mutant seedlings grown in the absence of sugar show decreased primary root growth and altered columella cells in root caps; however, these mutant defects are rescued by Suc, Glc, or Fru. In seedlings grown without sugar, significant up-regulation of photosynthetic gene expression and chlorophyll accumulation was found in ann-mutant cotyledons compared to that in wild type, which indicates potential sugar starvation in the roots of ann-mutant seedlings. Unexpectedly, the overall sugar content of ann-mutant primary roots was significantly higher than that of wild-type roots when grown without sugar. To examine the diffusion of sugar along the entire root to the root tip, we examined the unloading pattern of carboxyfluorescein dye and found that post-phloem sugar transport was impaired in ann-mutant root tips compared to that in wild type. Increased levels of ROS and callose were detected in the root tips of ann-mutant seedlings grown without Suc, the latter of which would restrict plasmodesmal sugar transport to root tips. Our results indicate that ANN1 and ANN2 play an important role in post-phloem sugar transport to the root tip, which in turn indirectly influences photosynthetic rates in cotyledons. This study expands our understanding of the function of annexins in plants.

},
	author = {Wang, J and Song, J and Clark, G and Roux, S J}
}
@inbook {13119,
	title = {Generation of transgenic spores of the fern Ceratopteris richardii to analyze Ca2+ dynamics during gravity-directed polarization.},
	booktitle = {Current Advances in Fern Research},
	year = {2018},
	pages = {285-303},
	publisher = {Springer International Publishing AG},
	organization = {Springer International Publishing AG},
	abstract = {
	Spores from the fern, Ceratopteris richardii, have been used to study gravity-directed cell polarization for over three decades. This system is ideal for these studies because it has a highly-predictable growth and developmental pattern and primarily responds to the mechanical force of gravity during polarization. Early studies on the development in this system showed that during the first 24 h of germination, Ceratopteris spores establish a Ca2+ concentration differential along the outer periphery of the cell that is defined by the uptake of Ca2+ through channels at the bottom of the spore and an efflux of Ca2+ through pumps at the top. This 100-fold [Ca2+] differential is sensitive to the direction and magnitude of the gravitational force. In a low-gravity environment or when the uptake of Ca2+ is blocked, spore polarization becomes random. These results support the hypothesis that the uptake of Ca2+ is necessary for gravity-directed polarization in Ceratopteris spores. For many years, studies of Ceratopteris were limited by the inability to produce stable transformants. However, recent protocols have led to the first stably transformed lines in Ceratopteris richardii. This work reviews and discusses the latest studies of gravity-induced changes in Ca2+ transport dynamics in Ceratopteris spores, the use of transformation protocols to overexpress or knock-out genes relevant to the transport of Ca2+ in Ceratopteris, and the potential value of mutants to more thoroughly understand the role of Ca2+ transport dynamics in gravity-directed polarization of spores. 

},
	url = {https://doi.org/10.1007/978-3-319-75103-0},
	author = {Cannon, AE and Salmi, ML and Cantero, A and Roux, S J}
}
@article {13118,
	title = {An autonomous lab on a chip for space flight claibration of gravity-induced transcellular calcium polarization in signle-cell fern spores.},
	journal = {Lab on a Chip},
	volume = {17},
	year = {2017},
	pages = {1095-1103},
	abstract = {
	This report describes the development of lab-on-a-chip device designed to measure changes in cellular\&nbsp;ion gradients that are induced by changes in gravitational (g) forces. The bioCD presented here detects differential calcium ion concentrations outside of individual cells. The device includes sufficient replicates for statistical analysis of the gradients around multiple single cells and around control wells that are empty or include dead cells. In the data presented, the degree of the cellular response correlates with the magnitude of the g-force applied via rotation of the bioCD. The experiments recorded the longest continuous observation of a cellular response to hypergravity made to date, and they demonstrate the potential utility of this device for assaying the threshold of cells{\textquoteright} g-force responses in spaceflight conditions

},
	author = {Park, J and Salmi, ML and Wan Salim, WWA and Rademacher, A and Wickizer, B and Schooley, A and Benton, J and Cantero, A and Argote, PF and Ren, M and Zhang, M. and Porterfield, D M and Ricco, AJ and Roux, S J and Rickus, JL}
}
@article {7743,
	title = {Apyrase inhibitors enhance the ability of diverse fungicides to inhibit the growth of different plant pathogenic fungi},
	journal = {Molecular Plant Pathology},
	year = {2016},
	month = {Sept 2016},
	pages = {1-12},
	abstract = {\&nbsp;A previous study has demonstrated that the treatment of Arabi-dopsis plants with chemical inhibitors of apyrase enzymesincreases their sensitivity to herbicides. In this study, we foundthat the addition of the same or related apyrase inhibitors couldpotentiate the ability of different fungicides to inhibit the growthof five different pathogenic fungi in plate growth assays. Thegrowth of all five fungi was partially inhibited by three commonlyused fungicides: copper octanoate, myclobutanil and propicona-zole. However, when these fungicides were individually tested incombination with any one of four different apyrase inhibitors(AI.1, AI.10, AI.13 or AI.15), their potency to inhibit the growthof five fungal pathogens was increased significantly relative totheir application alone. The apyrase inhibitors were most effec-tive in potentiating the ability of copper octanoate to inhibit fun-gal growth, and least effective in combination withpropiconazole. Among the five pathogens assayed, that mostsensitive to the fungicide-potentiating effects of the inhibitorswas Sclerotinia sclerotiorum. Overall, among the 60 treatmentcombinations tested (five pathogens, four apyrase inhibitors,three fungicides), the addition of apyrase inhibitors increased sig-nificantly the sensitivity of fungi to the fungicide treatments in53 of the combinations. Consistent with their predicted mode ofaction, inhibitors AI.1, AI.10 and AI.13 each increased the levelof propiconazole retained in one of the fungi, suggesting thatthey could partially block the ability of efflux transporters toremove propiconazole from these fungi.\&nbsp;},
	url = {http://onlinelibrary.wiley.com/doi/10.1111/mpp.12458/epdf},
	author = {Tripathy, M and Weeraratne, G and Clark, G and Roux, S J}
}
@article {7744,
	title = {Science Educational Outreach Programs That Benefit Students and Scientists.},
	journal = {PLoS Biology},
	volume = {14},
	number = {2},
	year = {2016},
	month = {Feb 2016},
	abstract = {Both scientists and the public would benefit from improved communication of basic scientific research and from integrating scientists into education outreach, but opportunities to support these efforts are limited. We have developed two low-cost programs{\textemdash}"Present Your PhD Thesis to a 12-Year-Old" and "Shadow a Scientist{\textquotedblright}{\textemdash}that combine training in science communication with outreach to area middle schools. We assessed the outcomes of these programs and found a 2-fold benefit: scientists improve their communication skills by explaining basic science research to a general audience, and students{\textquoteright} enthusiasm for science and their scientific knowledge are increased. Here we present details about both programs, along with our assessment of them, and discuss the feasibility of exporting these programs to other universities.},
	url = {http://dx.doi.org/10.1371/journal.pbio.1002368},
	author = {Clark, G and Russell, J and Enveart, P and Gracia, B and Wessel, A and Jarmoskaite, I and Polioudakis, D and Stuart, Y and Gonzalez, T and MacKrell, A and Rodenbusch, S and Stovall, G and Beckham, J and Montgomery, M and Tasneem, T and Jones, J and Simmons, S and Roux, S}
}
@article {7741,
	title = {Modulation of Root Skewing in Arabidopsis by Apyrases and Extracellular ATP.},
	journal = {Plant \& Cell Physiology},
	volume = {56},
	year = {2015},
	month = {Sept 2015},
	pages = {2197-2206},
	abstract = {When plant primary roots grow along a tilted surface that is impenetrable, they can undergo a slanted deviation from the direction of gravity called skewing. Skewing is induced by touch stimuli which the roots experience as they grow along the surface. Touch stimuli also induce the release of extracellular ATP (eATP) into the plant{\textquoteright}s extracellular matrix, and two apyrases (NTPDases) in Arabidopsis, APY1 and APY2, can help regulate the concentration of eATP. The primary roots of seedlings overexpressing APY1 show less skewing than wild-type plants. Plants suppressed in their expression of APY1 show more skewing than wild-type plants. Correspondingly, chemical inhibition of apyrase activity increased skewing in mutants and wild-type roots. Exogenous application of ATP or ATPγS also increased skewing in wild-type roots, which could be blocked by co-incubation with a purinergic receptor antagonist. These results suggest a model in which gradients of eATP set up by differential touch stimuli along roots help direct skewing in roots growing along an impenetrable surface.},
	author = {Yang, X and Wang, B and Farris, B and Clark, G and Roux, S J}
}
@article {7740,
	title = {Proteomic study of microsomal proteins reveals a key role for Arabidopsis Annexin 1 in mediating heat stress-induced increase in intracellular calcium levels. },
	journal = {Molecular \& Cellular Proteomics},
	volume = {14},
	year = {2015},
	month = {Mar 2015},
	pages = {686-694},
	abstract = {To understand the early signaling steps in the response of plant cells to increased environmental temperature, 2-D difference gel electrophoresis was used to study the proteins in microsomes of Arabidopsis seedlings that are regulated early during heat stress. Using mass spectrometry, 19 microsomal proteins that showed an altered expression level within 5 min after heat treatment were identified. Among these proteins, annexin 1 (AtANN1) was one of those up-regulated rapidly after heat-shock treatment. Functional studies show loss-of-function mutants for AtANN1 and its close homolog AtANN2 were more sensitive to heat-shock treatment, whereas plants overexpressing AtANN1 showed more resistance to this treatment. Correspondingly, the heat-induced expression of heat-shock proteins and heat-shock factors is inhibited in ann1/ann2 double mutant, and the heat-activated increase in cytoplasmic calcium concentration ([Ca(2+)]cyt) is greatly impaired in the ann1 mutant and almost undetectable in ann1/ann2 double mutant. Taken together these results suggest that AtANN1 is important in regulating the heat-induced increase in [Ca(2+)]cyt and in the response of Arabidopsis seedlings to heat stress.},
	author = {X Wang and Ma, X and Wang, H and Li, B and Clark, G and Guo, Y and Roux, S and Sun, D and Tang, W}
}
@article {7725,
	title = {Biochemical characterization of Arabidopsis APYRASE family reveals their roles in regulating endomembrane NDP/NMP homeostasis.},
	journal = {Biochemical J},
	volume = {472},
	year = {2015},
	month = {Sept 2015},
	pages = {43-54},
	abstract = {\&nbsp;Plant apyrases are nucleoside triphosphate diphosphohydolases and have been implicated in an array of functions within the plant including the regulation of extracellular ATP. Arabidopsis encodes a family of seven membrane bound apyrases (AtAPY1 to 7) comprised of three distinct clades all of which contain the five conserved apyrase domains. Subcellular localization of all seven Arabidopsis apyrases indicated that they all localize to internal membranes comprising the cis-Golgi, ER and endosome, indicating an endo-apyrase classification for the entire family. The complementation of a yeast double mutant (Δynd1Δgda1) which lacks apyrase activity indicated that all members could function as endo-apyrases except AtAPY7 which was unable to complement the yeast mutant. Complementation of the mutant yeast using characterized human apyrases demonstrated that functional complementation of the mutant could only be accomplished using a functional endo-apyrase (NTPDase6), with no complementation occurring when using a characterized human ecto-apyrase (NTPDase1). An analysis of substrate specificity for the Arabidopsis apyrases AtAPY1 to 6 indicated that each member has a distinct set of preferred substrates covering various NDPs and NTPs. The Arabidopsis apyrase AtAPY3 was the only member to display a strong preference for NTPs, with other members mainly exhibiting NDP substrate preferences.\&nbsp;},
	author = {Chiu, T-Y and Lao, J and Manalansan, B and Loqu{\'e}, D and Roux, S J and Heazlewood, JL}
}
@article {2937,
	title = {Brassinazole resistant 1 (BZR1)-dependent brassinosteroid signalling pathway leads to ectopic activation of quiescent cell division and suppresses columella stem cell differentiation.},
	journal = {J Exp Bot},
	volume = {66},
	number = {15},
	year = {2015},
	month = {2015 Aug},
	pages = {4835-49},
	abstract = {Previous publications have shown that BRI1 EMS suppressor 1 (BES1), a positive regulator of the brassinosteroid (BR) signalling pathway, enhances cell divisions in the quiescent centre (QC) and stimulates columella stem cell differentiation. Here, it is demonstrated that BZR1, a BES1 homologue, also promotes cell divisions in the QC, but it suppresses columella stem cell differentiation, opposite to the action of BES1. In addition, BR and its BZR1-mediated signalling pathway are shown to alter the expression/subcellular distribution of pin-formed (PINs), which may result in changes in auxin movement. BR promotes intense nuclear accumulation of BZR1 in the root tip area, and the binding of BZR1 to the promoters of several root development-regulating genes, modulating their expression in the root stem cell niche area. These BZR1-mediated signalling cascades may account for both the ectopic activation of QC cell divisions as well as the suppression of the columella stem cell differentiation. They could also inhibit auxin-dependent distal stem cell differentiation by antagonizing the auxin/WOX5-dependent pathway. In conclusion, BZR1-/BES1-mediated BR signalling pathways show differential effects on the maintenance of root apical meristem activities: they stimulate ectopic QC division while they show opposite effects on the differentiation of distal columella stem cells in a BR concentration- and BZR1-/BES1-dependent manner.},
	issn = {1460-2431},
	doi = {10.1093/jxb/erv316},
	author = {Lee, Hak-Soo and Kim, Yoon and Pham, Giang and Kim, Ju Won and Song, Ji-Hye and Lee, Yew and Hwang, Yong-Sic and Roux, Stanley J and Kim, Soo-Hwan}
}
@article {2926,
	title = {A self-referencing biosensor for real-time monitoring of physiological ATP transport in plant systems.},
	journal = {Biosens Bioelectron},
	volume = {74},
	year = {2015},
	month = {2015 Dec 15},
	pages = {37-44},
	abstract = {The objective of this study was to develop a self-referencing electrochemical biosensor for the direct measurement of ATP flux into the extracellular matrix by living cells/organisms. The working mechanism of the developed biosensor is based on the activity of glycerol kinase and glycerol-3-phosphate oxidase. A stratified bi-enzyme nanocomposite was created using a protein-templated silica sol gel encapsulation technique on top of graphene-modified platinum electrodes. The biosensor exhibited excellent electrochemical performance with a sensitivity of 2.4{\textpm}1.8nA/{\textmu}M, a response time of 20{\textpm}13s and a lower detection limit of 1.3{\textpm}0.7nM. The self-referencing biosensor was used to measure exogenous ATP efflux by (i) germinating Ceratopteris spores and (ii) growing Zea mays L. roots. This manuscript demonstrates the first development of a non-invasive ATP micro-biosensor for the direct measurement of eATP transport in living tissues. Before this work, assays of eATP have not been able to record the temporally transient movement of ATP at physiological levels (nM and sub-nM). The method demonstrated here accurately measured [eATP] flux in the immediate vicinity of plant cells. Although these proof of concept experiments focus on plant tissues, the technique developed herein is applicable to any living tissue, where nanomolar concentrations of ATP play a critical role in signaling and development. This tool will be invaluable for conducting hypothesis-driven life science research aimed at understanding the role of ATP in the extracellular environment.},
	issn = {1873-4235},
	doi = {10.1016/j.bios.2015.05.027},
	author = {Vanegas, Diana C and Clark, Greg and Cannon, Ashley E and Roux, Stanley and Chaturvedi, Prachee and McLamore, Eric S}
}
@article {2924,
	title = {Studying molecular changes during gravity perception and response in a single cell.},
	journal = {Methods Mol Biol},
	volume = {1309},
	year = {2015},
	month = {2015},
	pages = {199-207},
	abstract = {Early studies revealed a highly predictable pattern of gravity-directed growth and development in Ceratopteris richardii spores. This makes the spores a valuable model system for the study of how a single cell senses and responds to the force of gravity. Gravity regulates both the direction and magnitude of a trans-cell calcium current in germinating spores, and the orientation of this current predicts the polarization of spore development. Molecular techniques have been developed to evaluate the transcriptomic and proteomic profiles of spores before and after gravity establishes the polarity of their development. Here we describe these techniques, along with protocols for sterilizing the spores, sowing them in a solid or liquid growth media, and evaluating germination.},
	issn = {1940-6029},
	doi = {10.1007/978-1-4939-2697-8_15},
	author = {Cannon, Ashley E and Salmi, Mari L and Bushart, Thomas J and Roux, Stanley J}
}
@article {2961,
	title = {Between two fern genomes.},
	journal = {Gigascience},
	volume = {3},
	year = {2014},
	month = {2014},
	pages = {15},
	abstract = {Ferns are the only major lineage of vascular plants not represented by a sequenced nuclear genome. This lack of genome sequence information significantly impedes our ability to understand and reconstruct genome evolution not only in ferns, but across all land plants. Azolla and Ceratopteris are ideal and complementary candidates to be the first ferns to have their nuclear genomes sequenced. They differ dramatically in genome size, life history, and habit, and thus represent the immense diversity of extant ferns. Together, this pair of genomes will facilitate myriad large-scale comparative analyses across ferns and all land plants. Here we review the unique biological characteristics of ferns and describe a number of outstanding questions in plant biology that will benefit from the addition of ferns to the set of taxa with sequenced nuclear genomes. We explain why the fern clade is pivotal for understanding genome evolution across land plants, and we provide a rationale for how knowledge of fern genomes will enable progress in research beyond the ferns themselves.},
	issn = {2047-217X},
	doi = {10.1186/2047-217X-3-15},
	author = {Sessa, Emily B and Banks, Jo Ann and Barker, Michael S and Der, Joshua P and Duffy, Aaron M and Graham, Sean W and Hasebe, Mitsuyasu and Langdale, Jane and Li, Fay-Wei and Marchant, D Blaine and Pryer, Kathleen M and Rothfels, Carl J and Roux, Stanley J and Salmi, Mari L and Sigel, Erin M and Soltis, Douglas E and Soltis, Pamela S and Stevenson, Dennis W and Wolf, Paul G}
}
@article {2962,
	title = {Structure and function of CrACA1, the major PM-type Ca2+-ATPase, expressed at the peak of the gravity-directed trans-cell calcium current in spores of the fern Ceratopteris richardii.},
	journal = {Plant Biol (Stuttg)},
	volume = {16 Suppl 1},
	year = {2014},
	month = {2014 Jan},
	pages = {151-7},
	abstract = {Spores of the fern Ceratopteris richardii have proven to be a valuable single-cell system for studying gravity responses. The earliest cellular change directed by gravity in these cells is a trans-cell calcium current, which peaks near 10~h after the spores are induced to germinate. This current is needed for gravity-directed axis alignment, and its peak is coincident with the time period when gravity polarises the direction of subsequent nuclear migration and rhizoid growth. Transcriptomic analysis of genes expressed at the 10-h time point revealed several that encode proteins likely to be key components that either drive the current or regulate it. Notable among these is a plasma membrane (PM)-type Ca(2+) ATPase, CrACA1, whose activity pumping Ca(2+) out of cells is regulated by gravity. This report provides an initial characterisation of the structure and expression of this protein, and demonstrates its heterologous function complementing the K616 mutant of yeast, which is deficient in PM-type Ca(2+) pump activity. Gravity-induced changes in the trans-cell Ca(2+) current occur within seconds, a result consistent with the hypothesis that the force of gravity can rapidly alter the post-translational state of the channels and pumps that drive this current across spore cells. This report identifies a transporter likely to be a key driver of the current, CrACA1, and characterises the role of this protein in early germination and gravity-driven polarity fixation through analysis of expression levels, functional complementation and pharmacological treatments. These data, along with newly available transcriptomic data obtained at the 10-h time point, indicate that CrACA1 is present, functional and likely a major contributing component of the trans-cell Ca(2+) efflux. CrACA1 is not necessary for polar axis alignment, but pharmacological perturbations of it disrupt rhizoid development. These data support and help refine the post-translational modification model for gravity responses.},
	keywords = {Amino Acid Sequence, Calcium, Calcium-Transporting ATPases, Cell Membrane, Enzyme Assays, Enzyme Inhibitors, Ferns, Genetic Complementation Test, Gravitation, Molecular Sequence Data, Plant Proteins, Protein Structure, Tertiary, Sequence Alignment, Spores, Structure-Activity Relationship},
	issn = {1438-8677},
	doi = {10.1111/plb.12107},
	author = {Bushart, T J and Cannon, A and Clark, G and Roux, S J}
}
@article {2958,
	title = {Breakthroughs spotlighting roles for extracellular nucleotides and apyrases in stress responses and growth and development.},
	journal = {Plant Sci},
	volume = {225},
	year = {2014},
	month = {2014 Aug},
	pages = {107-16},
	abstract = {Animal and plant cells release nucleotides into their extracellular matrix when touched, wounded, and when their plasma membranes are stretched during delivery of secretory vesicles and growth. These released nucleotides then function as signaling agents that induce rapid increases in the concentration of cytosolic calcium, nitric oxide and superoxide. These, in turn, are transduced into downstream physiological changes. These changes in plants include changes in the growth of diverse tissues, in gravitropism, and in the opening and closing of stomates. The concentration of extracellular nucleotides is controlled by various phosphatases, prominent among which are apyrases EC 3.6.1.5 (nucleoside triphosphate diphosphohydrolases, NTPDases). This review provides phylogenetic and pHMM analyses of plant apyrases as well as analysis of predicted post-translational modifications for Arabidopsis apyrases. This review also summarizes and discusses recent advances in research on the roles of apyrases and extracellular nucleotides in controlling plant growth and development. These include new findings that document how apyrases and extracellular nucleotides control auxin transport, modulate stomatal aperture, and mediate biotic and abiotic stress responses, and on how apyrase suppression leads to growth inhibition.},
	keywords = {Adaptation, Physiological, Antigens, CD, Apyrase, Arabidopsis, Arabidopsis Proteins, Indoleacetic Acids, Nucleotides, Plant Stomata, Protein Processing, Post-Translational, Stress, Physiological},
	issn = {1873-2259},
	doi = {10.1016/j.plantsci.2014.06.002},
	author = {Clark, Greg B and Morgan, Reginald O and Fernandez, Maria-Pilar and Salmi, Mari L and Roux, Stanley J}
}
@article {2943,
	title = {Apyrase suppression raises extracellular ATP levels and induces gene expression and cell wall changes characteristic of stress responses.},
	journal = {Plant Physiol},
	volume = {164},
	number = {4},
	year = {2014},
	month = {2014 Apr},
	pages = {2054-67},
	abstract = {Plant cells release ATP into their extracellular matrix as they grow, and extracellular ATP (eATP) can modulate the rate of cell growth in diverse tissues. Two closely related apyrases (APYs) in Arabidopsis (Arabidopsis thaliana), APY1 and APY2, function, in part, to control the concentration of eATP. The expression of APY1/APY2 can be inhibited by RNA interference, and this suppression leads to an increase in the concentration of eATP in the extracellular medium and severely reduces growth. To clarify how the suppression of APY1 and APY2 is linked to growth inhibition, the gene expression changes that occur in seedlings when apyrase expression is suppressed were assayed by microarray and quantitative real-time-PCR analyses. The most significant gene expression changes induced by APY suppression were in genes involved in biotic stress responses, which include those genes regulating wall composition and extensibility. These expression changes predicted specific chemical changes in the walls of mutant seedlings, and two of these changes, wall lignification and decreased methyl ester bonds, were verified by direct analyses. Taken together, the results are consistent with the hypothesis that APY1, APY2, and eATP play important roles in the signaling steps that link biotic stresses to plant defense responses and growth changes.},
	keywords = {Adenosine Triphosphate, Apyrase, Arabidopsis, Arabidopsis Proteins, Cell Wall, Down-Regulation, Extracellular Matrix, Extracellular Space, Gene Expression Regulation, Plant, Gene Ontology, Genes, Plant, Hydrogen Peroxide, Lignin, Mutation, Oligonucleotide Array Sequence Analysis, Peroxidase, Plant Roots, Real-Time Polymerase Chain Reaction, Reproducibility of Results, RNA Interference, RNA, Messenger, Stress, Physiological, Up-Regulation},
	issn = {1532-2548},
	doi = {10.1104/pp.113.233429},
	author = {Lim, Min Hui and Wu, Jian and Yao, Jianchao and Gallardo, Ignacio F and Dugger, Jason W and Webb, Lauren J and Huang, James and Salmi, Mari L and Song, Jawon and Clark, Greg and Roux, Stanley J}
}
@article {2947,
	title = {A start point for extracellular nucleotide signaling.},
	journal = {Mol Plant},
	volume = {7},
	number = {6},
	year = {2014},
	month = {2014 Jun},
	pages = {937-8},
	keywords = {Gene Expression Regulation, Plant, Nucleotides, Signal Transduction},
	issn = {1752-9867},
	doi = {10.1093/mp/ssu023},
	author = {Roux, Stanley J}
}
@article {2955,
	title = {Current status and proposed roles for nitric oxide as a key mediator of the effects of extracellular nucleotides on plant growth.},
	journal = {Front Plant Sci},
	volume = {4},
	year = {2013},
	month = {2013},
	pages = {427},
	abstract = {Recent data indicate that nucleotides are released into the extracellular matrix during plant cell growth, and that these extracellular nucleotides induce signaling changes that can, in a dose-dependent manner, increase or decrease the cell growth. After activation of a presumed receptor, the earliest signaling change induced by extracellular nucleotides is an increase in the concentration of cytosolic Ca(2+), but rapidly following this change is an increase in the cellular level of nitric oxide (NO). In Arabidopsis, mutants deficient in nitrate reductase activity (nia1nia2) have drastically reduced nitric oxide production and cannot transduce the effects of applied nucleotides into growth changes. Both increased levels of extracellular nucleotides and increased NO production inhibit auxin transport and inhibit growth, and these effects are potentially due to disruption of the localization and/or function of auxin transport facilitators. However, because NO- and auxin-induced signaling pathways can intersect at multiple points, there may be diverse ways by which the induction of NO by extracellular ATP could modulate auxin signaling and thus influence growth. This review will discuss these optional mechanisms and suggest possible regulatory routes based on current experimental data and predictive computational analyses.},
	issn = {1664-462X},
	doi = {10.3389/fpls.2013.00427},
	author = {Salmi, Mari L and Clark, Greg and Roux, Stanley J}
}
@article {2938,
	title = {Co-regulation of exine wall patterning, pollen fertility and anther dehiscence by~Arabidopsis apyrases 6 and 7.},
	journal = {Plant Physiol Biochem},
	volume = {69},
	year = {2013},
	month = {2013 Aug},
	pages = {62-73},
	abstract = {An NCBI nucleotide blast keyed to apyrase (ATP-diphosphohydrolases, EC 3.6.1.5) conserved regions revealed five apyrases, AtAPYs (3-7), in addition to the previously identified AtAPY1 and 2. Here we report the functional analyses of two of the newly defined apyrases, AtAPY6 and AtAPY7. We analyzed tissue specificity of AtAPY6 and 7 expression by qRT-PCR and promoter:GUS fusion assays. We characterized the phenotypes of single and double knockout mutants for AtAPY6 and 7 in anther and pollen by light microscopy and electron microscopy. The transcripts of both AtAPY6 and 7 are expressed in mature pollen grains. Single knockout mutants of AtAPY6 and 7 displayed a minor change in pollen exine pattern under scanning electron microscopy without obvious change in fertility. Double knockout mutants of AtAPY6 and 7 (apy6apy7) displayed severe defects in pollen exine pattern, deformed pollen shape and reduced male fertility. An analysis of pollen from heterozygous apy6apy7 plants suggests that the defects in pollen exine wall are determined by the diploid genome. Our findings demonstrate that AtAPY6 and AtAPY7 are enzymes that play an important role in exine development of pollen grains, possibly through regulating the production of key polysaccharides needed for proper assembly of the exine layer.},
	keywords = {Apyrase, Arabidopsis, Arabidopsis Proteins, Flowers, Gene Expression Regulation, Plant, Golgi Apparatus, Plants, Genetically Modified, Pollen},
	issn = {1873-2690},
	doi = {10.1016/j.plaphy.2013.04.022},
	author = {Yang, Jian and Wu, Jian and Romanovicz, Dwight and Clark, Greg and Roux, Stanley J}
}
@article {2919,
	title = {RNA-seq analysis identifies potential modulators of gravity response in spores of Ceratopteris (Parkeriaceae): evidence for modulation by calcium pumps and apyrase activity.},
	journal = {Am J Bot},
	volume = {100},
	number = {1},
	year = {2013},
	month = {2013 Jan},
	pages = {161-74},
	abstract = {PREMISE OF THE STUDY: Gravity regulates the magnitude and direction of a trans-cell calcium current in germinating spores of Ceratopteris richardii. Blocking this current with nifedipine blocks the spore{\textquoteright}s downward polarity alignment, a polarization that is fixed by gravity \~{}10 h after light induces the spores to germinate. RNA-seq analysis at 10 h was used to identify genes potentially important for the gravity response. The data set will be valuable for other developmental and phylogenetic studies.

METHODS: De novo Newbler assembly of 958 527 reads from Roche 454 sequencing was executed. The sequences were identified and analyzed using in silico methods. The roles of endomembrane Ca(2+)-ATPase pumps and apyrases in the gravity response were further tested using pharmacological agents.

KEY RESULTS: Transcripts related to calcium signaling and ethylene biosynthesis were identified as notable constituents of the transcriptome. Inhibiting the activity of endomembrane Ca(2+)-ATPase pumps with 2,5-di-(t-butyl)-1,4-hydroquinone diminished the trans-cell current, but increased the orientation of the polar axis to gravity. The effects of applied nucleotides and purinoceptor antagonists gave novel evidence implicating extracellular nucleotides as regulators of the gravity response in these fern spores.

CONCLUSIONS: In addition to revealing general features of the transcriptome of germinating spores, the results highlight a number of calcium-responsive and light-receptive transcripts. Pharmacologic assays indicate endomembrane Ca(2+)-ATPases and extracellular nucleotides may play regulatory roles in the gravity response of Ceratopteris spores.},
	keywords = {Adenosine Triphosphate, Amino Acid Sequence, Apyrase, Calcium, Calcium-Transporting ATPases, Cell Polarity, Databases, Genetic, Enzyme Inhibitors, Extracellular Space, Gene Expression Regulation, Plant, Genes, Plant, Gravitation, Molecular Sequence Data, Photoreceptors, Plant, Pteridaceae, RNA, Messenger, Sequence Analysis, RNA, Signal Transduction, Spores},
	issn = {1537-2197},
	doi = {10.3732/ajb.1200292},
	author = {Bushart, Thomas J and Cannon, Ashley E and Ul Haque, Aeraj and San Miguel, Phillip and Mostajeran, Kathy and Clark, Gregory B and Porterfield, D Marshall and Roux, Stanley J}
}
@article {2960,
	title = {Evolutionary adaptation of plant annexins has diversified their molecular structures, interactions and functional roles.},
	journal = {New Phytol},
	volume = {196},
	number = {3},
	year = {2012},
	month = {2012 Nov},
	pages = {695-712},
	abstract = {Annexins are an homologous, structurally related superfamily of proteins known to associate with membrane lipid and cytoskeletal components. Their involvement in membrane organization, vesicle trafficking and signaling is fundamental to cellular processes such as growth, differentiation, secretion and repair. Annexins exist in some prokaryotes and all eukaryotic phyla within which plant annexins represent a monophyletic clade of homologs descended from green algae. Genomic, proteomic and transcriptomic approaches have provided data on the diversity, cellular localization and expression patterns of different plant annexins. The availability of 35 complete plant genomes has enabled systematic comparative analysis to determine phylogenetic relationships, characterize structures and observe functional specificity between and within individual subfamilies. Short amino termini and selective erosion of the canonical type 2 calcium coordinating sites in domains 2 and 3 are typical of plant annexins. The convergent evolution of alternate functional motifs such as {\textquoteright}KGD{\textquoteright}, redox-sensitive Cys and hydrophobic Trp/Phe residues argues for their functional relevance and contribution to mechanistic diversity in plant annexins. This review examines recent findings and advances in plant annexin research with special focus on their structural diversity, cellular and molecular interactions and their potential integrated functions in the broader context of physiological responses.},
	keywords = {Adaptation, Physiological, Amino Acid Motifs, Annexins, Cell Membrane, Evolution, Molecular, Gene Expression Profiling, Genetic Variation, Markov Chains, Phylogeny, Plant Proteins, Plants, Protein Interaction Mapping, Proteome, Species Specificity, Structure-Activity Relationship},
	issn = {1469-8137},
	doi = {10.1111/j.1469-8137.2012.04308.x},
	author = {Clark, Greg B and Morgan, Reginald O and Fernandez, Maria-Pilar and Roux, Stanley J}
}
@article {2957,
	title = {AtAPY1 and AtAPY2 function as Golgi-localized nucleoside diphosphatases in Arabidopsis thaliana.},
	journal = {Plant Cell Physiol},
	volume = {53},
	number = {11},
	year = {2012},
	month = {2012 Nov},
	pages = {1913-25},
	abstract = {Nucleoside triphosphate diphosphohydrolases (NTPDases; apyrases) (EC 3.6.1.5) hydrolyze di- and triphosphate nucleotides, but not monophosphate nucleotides. They are categorized as E-type ATPases, have a broad divalent cation (Mg(2+), Ca(2+)) requirement for activation and are insensitive to inhibitors of F-type, P-type and V-type ATPases. Among the seven NTPDases identified in Arabidopsis, only APYRASE 1 (AtAPY1) and APYRASE 2 (AtAPY2) have been previously characterized. In this work, either AtAPY1 or AtAPY2 tagged with C-terminal green fluorescent protein (GFP) driven by their respective native promoter can rescue the apy1 apy2 double knockout (apy1 apy2 dKO) successfully, and confocal microscopy reveals that these two Arabidopsis apyrases reside in the Golgi apparatus. In Saccharomyces cerevisiae, both AtAPY1 and AtAPY2 can complement the Golgi-localized GDA1 mutant, rescuing its aberrant protein glycosylation phenotype. In Arabidopsis, microsomes of the wild type show higher substrate preferences toward UDP compared with other NDP substrates. Loss-of-function Arabidopsis AtAPY1 mutants exhibit reduced microsomal UDPase activity, and this activity is even more significantly reduced in the loss-of-function AtAPY2 mutant and in the AtAPY1/AtAPY2 RNA interference (RNAi) technology repressor lines. Microsomes from wild-type plants also have detectable GDPase activity, which is significantly reduced in apy2 but not apy1 mutants. The GFP-tagged AtAPY1 or AtAPY2 constructs in the apy1 apy2 dKO plants can restore microsomal UDP/GDPase activity, confirming that they both also have functional competency. The cell walls of apy1, apy2 and the RNAi-silenced lines all have an increased composition of galactose, but the transport efficiency of UDP-galactose across microsomal membranes was not altered. Taken together, these results reveal that AtAPY1 and AtAPY2 are Golgi-localized nucleotide diphosphatases and are likely to have roles in regulating UDP/GDP concentrations in the Golgi lumen.},
	keywords = {Apyrase, Arabidopsis, Arabidopsis Proteins, Biological Transport, Cell Wall, Enzyme Activation, Galactose, Genetic Complementation Test, Glycosylation, Golgi Apparatus, Green Fluorescent Proteins, Guanosine Diphosphate, Intracellular Membranes, Microsomes, Promoter Regions, Genetic, Pyrophosphatases, RNA Interference, Saccharomyces cerevisiae, Uridine Diphosphate},
	issn = {1471-9053},
	doi = {10.1093/pcp/pcs131},
	author = {Chiu, Tsan-Yu and Christiansen, Katy and Moreno, Ignacio and Lao, Jeemeng and Loqu{\'e}, Dominique and Orellana, Ariel and Heazlewood, Joshua L and Clark, Greg and Roux, Stanley J}
}
@article {2956,
	title = {Root waving and skewing: unexpectedly in micro-g.},
	journal = {BMC Plant Biol},
	volume = {12},
	year = {2012},
	month = {2012},
	pages = {231},
	abstract = {Gravity has major effects on both the form and overall length of root growth. Numerous papers have documented these effects (over 300 publications in the last 5 years), the most well-studied being gravitropism, which is a growth re-orientation directed by gravity toward the earth{\textquoteright}s center. Less studied effects of gravity are undulations due to the regular periodic change in the direction root tips grow, called waving, and the slanted angle of growth roots exhibit when they are growing along a nearly-vertical surface, called skewing. Although diverse studies have led to the conclusion that a gravity stimulus is needed for plant roots to show waving and skewing, the novel results just published by Paul et al. (2012) reveal that this conclusion is not correct. In studies carried out in microgravity on the International Space Station, the authors used a new imaging system to collect digital photographs of plants every six hours during 15 days of spaceflight. The imaging system allowed them to observe how roots grew when their orientation was directed not by gravity but by overhead LED lights, which roots grew away from because they are negatively phototropic. Surprisingly, the authors observed both skewing and waving in spaceflight plants, thus demonstrating that both growth phenomena were gravity independent. Touch responses and differential auxin transport would be common features of root waving and skewing at 1-g and micro-g, and the novel results of Paul et al. will focus the attention of cell and molecular biologists more on these features as they try to decipher the signaling pathways that regulate root skewing and waving.},
	keywords = {Arabidopsis, Ecotype, Indoleacetic Acids, Models, Biological, Physical Stimulation, Plant Roots, Signal Transduction, Time-Lapse Imaging, Weightlessness},
	issn = {1471-2229},
	doi = {10.1186/1471-2229-12-231},
	author = {Roux, Stanley J}
}
@article {2939,
	title = {Identification and characterization of annexin gene family in rice.},
	journal = {Plant Cell Rep},
	volume = {31},
	number = {5},
	year = {2012},
	month = {2012 May},
	pages = {813-25},
	abstract = {Plant annexins are Ca(2+)-dependent phospholipid-binding proteins and are encoded by multigene families. They are implicated in the regulation of plant development as well as protection from drought and other stresses. They are well characterized in Arabidopsis, however no such characterization of rice annexin gene family has been reported thus far. With the availability of the rice genome sequence information, we have identified ten members of the rice annexin gene family. At the protein level, they share 16-64\% identity with predicted molecular masses ranging from 32 to 40 kDa. Phylogenetic analysis of rice annexins together with annexins from other monocots led to their classification into five different orthologous groups and share similar motif patterns in their protein sequences. Expression analysis by real-time RT-PCR revealed differential temporal and spatial regulation of these genes. The rice annexin genes are also found to be regulated in seedling stage by various abiotic stressors including salinity, drought, heat and cold. Additionally, in silico analysis of the putative upstream sequences was analyzed for the presence of stress-responsive cis-elements. These results provide a basis for further functional characterization of specific rice annexin genes at the tissue/developmental level and in response to abiotic stresses.},
	keywords = {Amino Acid Sequence, Annexins, Conserved Sequence, Gene Expression Regulation, Developmental, Gene Expression Regulation, Plant, Genome, Plant, Molecular Sequence Data, Multigene Family, Oryza sativa, Phylogeny, Promoter Regions, Genetic, Seedling, Sequence Alignment, Sequence Analysis, Protein, Stress, Physiological},
	issn = {1432-203X},
	doi = {10.1007/s00299-011-1201-0},
	author = {Jami, Sravan Kumar and Clark, Greg B and Ayele, Belay T and Roux, Stanley J and Kirti, P B}
}
@article {2944,
	title = {Role for apyrases in polar auxin transport in Arabidopsis.},
	journal = {Plant Physiol},
	volume = {160},
	number = {4},
	year = {2012},
	month = {2012 Dec},
	pages = {1985-95},
	abstract = {Recent evidence indicates that extracellular nucleotides regulate plant growth. Exogenous ATP has been shown to block auxin transport and gravitropic growth in primary roots of Arabidopsis (Arabidopsis thaliana). Cells limit the concentration of extracellular ATP in part through the activity of ectoapyrases (ectonucleoside triphosphate diphosphohydrolases), and two nearly identical Arabidopsis apyrases, APY1 and APY2, appear to share this function. These findings, plus the fact that suppression of APY1 and APY2 blocks growth in Arabidopsis, suggested that the expression of these apyrases could influence auxin transport. This report tests that hypothesis. The polar movement of [(3)H]indole-3-acetic acid in both hypocotyl sections and primary roots of Arabidopsis seedlings was measured. In both tissues, polar auxin transport was significantly reduced in apy2 null mutants when they were induced by estradiol to suppress the expression of APY1 by RNA interference. In the hypocotyl assays, the basal halves of APY-suppressed hypocotyls contained considerably lower free indole-3-acetic acid levels when compared with wild-type plants, and disrupted auxin transport in the APY-suppressed roots was reflected by their significant morphological abnormalities. When a green fluorescent protein fluorescence signal encoded by a DR5:green fluorescent protein construct was measured in primary roots whose apyrase expression was suppressed either genetically or chemically, the roots showed no signal asymmetry following gravistimulation, and both their growth and gravitropic curvature were inhibited. Chemicals that suppress apyrase activity also inhibit gravitropic curvature and, to a lesser extent, growth. Taken together, these results indicate that a critical step connecting apyrase suppression to growth suppression is the inhibition of polar auxin transport.},
	keywords = {Apyrase, Arabidopsis, Arabidopsis Proteins, Biological Transport, Ecotype, Estradiol, Fluorescence, Gravitation, Gravitropism, Green Fluorescent Proteins, Hypocotyl, Indoleacetic Acids, Mitosis, Nucleotides, Plant Roots, Recombinant Fusion Proteins, RNA Interference, Suppression, Genetic},
	issn = {1532-2548},
	doi = {10.1104/pp.112.202887},
	author = {Liu, Xing and Wu, Jian and Clark, Greg and Lundy, Stacey and Lim, Min Hui and Arnold, David and Chan, Jing and Tang, Wenqiang and Muday, Gloria K and Gardner, Gary and Roux, Stanley J}
}
@article {2963,
	title = {G-diversity discovered.},
	journal = {New Phytol},
	volume = {190},
	number = {1},
	year = {2011},
	month = {2011 Apr},
	pages = {1-3},
	keywords = {Heterotrimeric GTP-Binding Proteins, Multigene Family, Plant Proteins, Protein Subunits, Signal Transduction, Soybeans},
	issn = {1469-8137},
	doi = {10.1111/j.1469-8137.2011.03653.x},
	author = {Roux, Stan J}
}
@article {2934,
	title = {Apyrases, extracellular ATP and the regulation of growth.},
	journal = {Curr Opin Plant Biol},
	volume = {14},
	number = {6},
	year = {2011},
	month = {2011 Dec},
	pages = {700-6},
	abstract = {Although no definitive receptor for extracellular ATP (eATP) has been identified in plants, there is now stronger physiological evidence that the effects of eATP on plant growth are mediated by a receptor, or, as in animals, by multiple receptors. Recent papers clarify how extracellular nucleotides induce changes in [Ca(2+)](cyt), and the production of nitric oxide (NO) and reactive oxygen species. They document links between eATP signaling and the synthesis or transport of hormones, and they reveal that applied nucleotides can regulate the aperture of stomates, which release ATP when stimulated by light and hormones. Ectoapyrases (ecto-nucleoside triphosphate-diphosphohydrolase) help control both the diverse signaling changes and downstream growth changes induced by extracellular nucleotides by limiting their concentration in the extracellular matrix (ECM).},
	keywords = {Adenosine Triphosphate, Apyrase, Extracellular Matrix, Extracellular Space, Nitric Oxide, Plant Development, Plants},
	issn = {1879-0356},
	doi = {10.1016/j.pbi.2011.07.013},
	author = {Clark, Greg and Roux, Stanley J}
}
@article {2931,
	title = {Extracellular nucleotides and apyrases regulate stomatal aperture in Arabidopsis.},
	journal = {Plant Physiol},
	volume = {156},
	number = {4},
	year = {2011},
	month = {2011 Aug},
	pages = {1740-53},
	abstract = {This study investigates the role of extracellular nucleotides and apyrase enzymes in regulating stomatal aperture. Prior data indicate that the expression of two apyrases in Arabidopsis (Arabidopsis thaliana), APY1 and APY2, is strongly correlated with cell growth and secretory activity. Both are expressed strongly in guard cell protoplasts, as determined by reverse transcription-polymerase chain reaction and immunoblot analyses. Promoter activity assays for APY1 and APY2 show that expression of both apyrases correlates with conditions that favor stomatal opening. Correspondingly, immunoblot data indicate that APY expression in guard cell protoplasts rises quickly when these cells are moved from darkness into light. Both short-term inhibition of ectoapyrase activity by polyclonal antibodies and long-term suppression of APY1 and APY2 transcript levels significantly disrupt normal stomatal behavior in light. Stomatal aperture shows a biphasic response to applied adenosine 5{\textquoteright}-[γ-thio]triphosphate (ATPγS) or adenosine 5{\textquoteright}-[β-thio] diphosphate, with lower concentrations inducing stomatal opening and higher concentrations inducing closure. Equivalent concentrations of adenosine 5{\textquoteright}-O-thiomonophosphate have no effect on aperture. Two mammalian purinoceptor inhibitors block ATPγS- and adenosine 5{\textquoteright}-[β-thio] diphosphate-induced opening and closing and also partially block the ability of abscisic acid to induce stomatal closure and of light to induce stomatal opening. Treatment of epidermal peels with ATPγS induces increased levels of nitric oxide and reactive oxygen species, and genetically suppressing the synthesis of these agents blocks the effects of nucleotides on stomatal aperture. A luciferase assay indicates that treatments that induce either the closing or opening of stomates also induce the release of ATP from guard cells. These data favor the novel conclusion that ectoapyrases and extracellular nucleotides play key roles in regulating stomatal functions.},
	keywords = {Abscisic Acid, Adenosine Diphosphate, Adenosine Triphosphate, Apyrase, Arabidopsis, Arabidopsis Proteins, Enzyme Inhibitors, Extracellular Space, Gene Expression Regulation, Plant, Hydrogen Peroxide, Light, Models, Biological, Nitric Oxide, Nucleotides, Plant Stomata, Promoter Regions, Genetic, Pyridoxal Phosphate, RNA Interference, Thionucleotides, Triazines},
	issn = {1532-2548},
	doi = {10.1104/pp.111.174466},
	author = {Clark, Greg and Fraley, Devin and Steinebrunner, Iris and Cervantes, Andrew and Onyirimba, James and Liu, Angela and Torres, Jonathan and Tang, Wenqiang and Kim, Joshua and Roux, Stanley J}
}
@article {2922,
	title = {Changes in gravity rapidly alter the magnitude and direction of a cellular calcium current.},
	journal = {Planta},
	volume = {233},
	number = {5},
	year = {2011},
	month = {2011 May},
	pages = {911-20},
	abstract = {In single-celled spores of the fern Ceratopteris richardii, gravity directs polarity of development and induces a directional, trans-cellular calcium (Ca(2+)) current. To clarify how gravity polarizes this electrophysiological process, we measured the kinetics of the cellular response to changes in the gravity vector, which we initially estimated using the self-referencing calcium microsensor. In order to generate more precise and detailed data, we developed a silicon microfabricated sensor array which facilitated a lab-on-a-chip approach to simultaneously measure calcium currents from multiple cells in real time. These experiments revealed that the direction of the gravity-dependent polar calcium current is reversed in less than 25 s when the cells are inverted, and that changes in the magnitude of the calcium current parallel rapidly changing g-forces during parabolic flight on the NASA C-9 aircraft. The data also revealed a hysteresis in the response of cells in the transition from 2g to micro-g in comparison to cells in the micro-g to 2-g transition, a result consistent with a role for mechanosensitive ion channels in the gravity response. The calcium current is suppressed by either nifedipine (calcium-channel blocker) or eosin yellow (plasma membrane calcium pump inhibitor). Nifedipine disrupts gravity-directed cell polarity, but not spore germination. These results indicate that gravity perception in single plant cells may be mediated by mechanosensitive calcium channels, an idea consistent with some previously proposed models of plant gravity perception.},
	keywords = {Calcium, Calcium Channel Blockers, Calcium Signaling, Cell Membrane, Cell Polarity, Eosine Yellowish-(YS), Germination, Gravitropism, Hypogravity, Nifedipine, Plant Roots, Pteridaceae, Space Flight},
	issn = {1432-2048},
	doi = {10.1007/s00425-010-1343-2},
	author = {Salmi, Mari L and Ul Haque, Aeraj and Bushart, Thomas J and Stout, Stephen C and Roux, Stanley J and Porterfield, D Marshall}
}
@article {2950,
	title = {Both the stimulation and inhibition of root hair growth induced by extracellular nucleotides in Arabidopsis are mediated by nitric oxide and reactive oxygen species.},
	journal = {Plant Mol Biol},
	volume = {74},
	number = {4-5},
	year = {2010},
	month = {2010 Nov},
	pages = {423-35},
	abstract = {Root hairs secrete ATP as they grow, and extracellular ATP and ADP can trigger signaling pathways that regulate plant cell growth. In several plant tissues the level of extracellular nucleotides is limited in part by ectoapyrases (ecto-NTPDases), and the growth of these tissues is strongly influenced by their level of ectoapyrase expression. Both chemical inhibition of ectoapyrase activity and suppression of the expression of two ectoapyrase enzymes by RNAi in Arabidopsis resulted in inhibition of root hair growth. As assayed by a dose-response curve, different concentrations of the poorly hydrolysable nucleotides, ATPγS and ADPβS, could either stimulate (at 7.5-25~μM) or inhibit (at~>=~150~μM) the growth rate of root hairs in less than an hour. Equal amounts of AMPS, used as a control, had no effect on root hair growth. Root hairs of nia1nia2 mutants, which are suppressed in nitric oxide (NO) production, and of atrbohD/F mutants, which are suppressed in the production of H(2)O(2), did not show growth responses to applied nucleotides, indicating that the growth changes induced by these nucleotides in wild-type plants were likely transduced via NO and H(2)O(2) signals. Consistent with this interpretation, treatment of root hairs with different concentrations of ATPγS induced different accumulations of NO and H(2)O(2) in root hair tips. Two mammalian purinoceptor antagonists also blocked the growth responses induced by extracellular nucleotides, suggesting that they were initiated by a receptor-based mechanism.},
	keywords = {Adenosine Diphosphate, Adenosine Triphosphate, Apyrase, Arabidopsis, Hydrogen Peroxide, Nitric Oxide, Nucleotides, Plant Roots, Reactive Oxygen Species, RNA Interference, Thionucleotides},
	issn = {1573-5028},
	doi = {10.1007/s11103-010-9683-7},
	author = {Clark, Greg and Wu, Michael and Wat, Noel and Onyirimba, James and Pham, Trieu and Herz, Niculin and Ogoti, Justin and Gomez, Delmy and Canales, Arinda A and Aranda, Gabriela and Blizard, Misha and Nyberg, Taylor and Terry, Anne and Torres, Jonathan and Wu, Jian and Roux, Stanley J}
}
@article {2942,
	title = {Is annexin 1 a multifunctional protein during stress responses?},
	journal = {Plant Signal Behav},
	volume = {5},
	number = {3},
	year = {2010},
	month = {2010 Mar},
	pages = {303-7},
	abstract = {Accumulating evidence suggest that certain annexins can play a role in abiotic stress responses in plants. We found that for one member of the Arabidopsis thaliana annexin gene family, annexin 1 (AnnAt1), loss-of-function mutants are more sensitive to drought stress and gain-of-function mutants are more tolerant. We also found that AnnAt1 is able to regulate accumulation of H(2)O(2) in vivo in Arabidopsis cells based on the observation that the level of ROS accumulation following induction by ABA correlates with the level of AnnAt1 protein in transgenic Arabidopsis plants. Here we provide more commentary on the antioxidant activity of AnnAt1, critically assess the evidence that AnnAt1 and other annexins possess peroxidase activity, emphasize a redox-induced post-translational modification which occurs to AnnAt1 during ABA signaling, and discuss ways this annexin{\textquoteright}s membrane associations could mediate stress signaling while addressing the potential that AnnAt1 is a multifunctional protein in plants.},
	issn = {1559-2324},
	author = {Clark, Greg and Konopka-Postupolska, Dorota and Hennig, Jacek and Roux, Stanley}
}
@article {2935,
	title = {Apyrase (nucleoside triphosphate-diphosphohydrolase) and extracellular nucleotides regulate cotton fiber elongation in cultured ovules.},
	journal = {Plant Physiol},
	volume = {152},
	number = {2},
	year = {2010},
	month = {2010 Feb},
	pages = {1073-83},
	abstract = {Ectoapyrase enzymes remove the terminal phosphate from extracellular nucleoside tri- and diphosphates. In Arabidopsis (Arabidopsis thaliana), two ectoapyrases, AtAPY1 and AtAPY2, have been implicated as key modulators of growth. In fibers of cotton (Gossypium hirsutum), transcript levels for GhAPY1 and GhAPY2, two closely related ectoapyrases that have high sequence similarity to AtAPY1 and AtAPY2, are up-regulated when fibers enter their rapid growth phase. In an ovule culture system, fibers release ATP as they grow, and when their ectoapyrase activity is blocked by the addition of polyclonal anti-apyrase antibodies or by two different small molecule inhibitors, the medium ATP level rises and fiber growth is suppressed. High concentrations of the poorly hydrolyzable nucleotides ATPgammaS and ADPbetaS applied to the medium inhibit fiber growth, and low concentrations of them stimulate growth, but treatment with adenosine 5{\textquoteright}-O-thiomonophosphate causes no change in the growth rate. Both the inhibition and stimulation of growth by applied nucleotides can be blocked by an antagonist that blocks purinoceptors in animal cells, and by adenosine. Treatment of cotton ovule cultures with ATPgammaS induces increased levels of ethylene, and two ethylene antagonists, aminovinylglycine and silver nitrate, block both the growth stimulatory and growth inhibitory effects of applied nucleotides. In addition, the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid, lowers the concentration of nucleotide needed to promote fiber growth. These data indicate that ectoapyrases and extracellular nucleotides play a significant role in regulating cotton fiber growth and that ethylene is a likely downstream component of the signaling pathway.},
	keywords = {Amino Acids, Cyclic, Apyrase, Cotton Fiber, DNA, Plant, Ethylenes, Gene Expression Regulation, Plant, Gossypium, Molecular Sequence Data, Ovule, Plant Proteins, Sequence Analysis, DNA, Thionucleotides},
	issn = {1532-2548},
	doi = {10.1104/pp.109.147637},
	author = {Clark, Greg and Torres, Jonathan and Finlayson, Scott and Guan, Xueying and Handley, Craig and Lee, Jinsuk and Kays, Julia E and Chen, Z Jeffery and Roux, Stanley J}
}
@article {2941,
	title = {The role of annexin 1 in drought stress in Arabidopsis.},
	journal = {Plant Physiol},
	volume = {150},
	number = {3},
	year = {2009},
	month = {2009 Jul},
	pages = {1394-410},
	abstract = {Annexins act as targets of calcium signals in eukaryotic cells, and recent results suggest that they play an important role in plant stress responses. We found that in Arabidopsis (Arabidopsis thaliana), AnnAt1 (for annexin 1) mRNA levels were up-regulated in leaves by most of the stress treatments applied. Plants overexpressing AnnAt1 protein were more drought tolerant and knockout plants were more drought sensitive than ecotype Columbia plants. We also observed that hydrogen peroxide accumulation in guard cells was reduced in overexpressing plants and increased in knockout plants both before and after treatment with abscisic acid. Oxidative protection resulting from AnnAt1 overexpression could be due to the low level of intrinsic peroxidase activity exhibited by this protein in vitro, previously linked to a conserved histidine residue found in a peroxidase-like motif. However, analyses of a mutant H40A AnnAt1 protein in a bacterial complementation test and in peroxidase activity assays indicate that this residue is not critical to the ability of AnnAt1 to confer oxidative protection. To further examine the mechanism(s) linking AnnAt1 expression to stress resistance, we analyzed the reactive S3 cluster to determine if it plays a role in AnnAt1 oligomerization and/or is the site for posttranslational modification. We found that the two cysteine residues in this cluster do not form intramolecular or intermolecular bonds but are highly susceptible to oxidation-driven S-glutathionylation, which decreases the Ca(2+) affinity of AnnAt1 in vitro. Moreover, S-glutathionylation of AnnAt1 occurs in planta after abscisic acid treatment, which suggests that this modification could be important in regulating the cellular function of AnnAt1 during stress responses.},
	keywords = {Annexins, Arabidopsis, Arabidopsis Proteins, Droughts, Gene Expression Regulation, Plant, Oxidation-Reduction, Oxidative Stress, Plant Leaves, RNA, Messenger, Stress, Physiological},
	issn = {0032-0889},
	doi = {10.1104/pp.109.135228},
	author = {Konopka-Postupolska, Dorota and Clark, Greg and Goch, Grazyna and Debski, Janusz and Floras, Krzysztof and Cantero, Araceli and Fijolek, Bartlomiej and Roux, Stanley and Hennig, Jacek}
}
@article {2929,
	title = {Intersection of two signalling pathways: extracellular nucleotides regulate pollen germination and pollen tube growth via nitric oxide.},
	journal = {J Exp Bot},
	volume = {60},
	number = {7},
	year = {2009},
	month = {2009},
	pages = {2129-38},
	abstract = {Plant and animal cells release or secrete ATP by various mechanisms, and this activity allows extracellular ATP to serve as a signalling molecule. Recent reports suggest that extracellular ATP induces plant responses ranging from increased cytosolic calcium to changes in auxin transport, xenobiotic resistance, pollen germination, and growth. Although calcium has been identified as a secondary messenger for the extracellular ATP signal, other parts of this signal transduction chain remain unknown. Increasing the extracellular concentration of ATPgammaS, a poorly-hydrolysable ATP analogue, inhibited both pollen germination and pollen tube elongation, while the addition of AMPS had no effect. Because pollen tube elongation is also sensitive to nitric oxide, this raised the possibility that a connection exists between the two pathways. Four approaches were used to test whether the germination and growth effects of extracellular ATPgammaS were transduced via nitric oxide. The results showed that increases in extracellular ATPgammaS induced increases in cellular nitric oxide, chemical agonists of the nitric oxide signalling pathway lowered the threshold of extracellular ATPgammaS that inhibits pollen germination, an antagonist of guanylate cyclase, which can inhibit some nitric oxide signalling pathways, blocked the ATPgammaS-induced inhibition of both pollen germination and pollen tube elongation, and the effects of applied ATPgammaS were blocked in nia1nia2 mutants, which have diminished NO production. The concurrence of these four data sets support the conclusion that the suppression of pollen germination and pollen tube elongation by extracellular nucleotides is mediated in part via the nitric oxide signalling pathway.},
	keywords = {Adenosine Triphosphate, Arabidopsis, Germination, Nitric Oxide, Pollen Tube, Signal Transduction},
	issn = {1460-2431},
	doi = {10.1093/jxb/erp091},
	author = {Reichler, Stuart A and Torres, Jonathan and Rivera, Amy L and Cintolesi, Viviana A and Clark, Greg and Roux, Stanley J}
}
@article {2949,
	title = {Genome-scale cluster analysis of replicated microarrays using shrinkage correlation coefficient.},
	journal = {BMC Bioinformatics},
	volume = {9},
	year = {2008},
	month = {2008},
	pages = {288},
	abstract = {BACKGROUND: Currently, clustering with some form of correlation coefficient as the gene similarity metric has become a popular method for profiling genomic data. The Pearson correlation coefficient and the standard deviation (SD)-weighted correlation coefficient are the two most widely-used correlations as the similarity metrics in clustering microarray data. However, these two correlations are not optimal for analyzing replicated microarray data generated by most laboratories. An effective correlation coefficient is needed to provide statistically sufficient analysis of replicated microarray data.

RESULTS: In this study, we describe a novel correlation coefficient, shrinkage correlation coefficient (SCC), that fully exploits the similarity between the replicated microarray experimental samples. The methodology considers both the number of replicates and the variance within each experimental group in clustering expression data, and provides a robust statistical estimation of the error of replicated microarray data. The value of SCC is revealed by its comparison with two other correlation coefficients that are currently the most widely-used (Pearson correlation coefficient and SD-weighted correlation coefficient) using statistical measures on both synthetic expression data as well as real gene expression data from Saccharomyces cerevisiae. Two leading clustering methods, hierarchical and k-means clustering were applied for the comparison. The comparison indicated that using SCC achieves better clustering performance. Applying SCC-based hierarchical clustering to the replicated microarray data obtained from germinating spores of the fern Ceratopteris richardii, we discovered two clusters of genes with shared expression patterns during spore germination. Functional analysis suggested that some of the genetic mechanisms that control germination in such diverse plant lineages as mosses and angiosperms are also conserved among ferns.

CONCLUSION: This study shows that SCC is an alternative to the Pearson correlation coefficient and the SD-weighted correlation coefficient, and is particularly useful for clustering replicated microarray data. This computational approach should be generally useful for proteomic data or other high-throughput analysis methodology.},
	keywords = {Artificial Intelligence, Cluster Analysis, Computational Biology, Computer Simulation, Confidence Intervals, Gene Expression, Gene Expression Profiling, Genomics, Germination, Oligonucleotide Array Sequence Analysis, Probability, Pteridaceae, Research Design, Saccharomyces cerevisiae},
	issn = {1471-2105},
	doi = {10.1186/1471-2105-9-288},
	author = {Yao, Jianchao and Chang, Chunqi and Salmi, Mari L and Hung, Yeung Sam and Loraine, Ann and Roux, Stanley J}
}
@article {2940,
	title = {Ectopic expression of an annexin from Brassica juncea confers tolerance to abiotic and biotic stress treatments in transgenic tobacco.},
	journal = {Plant Physiol Biochem},
	volume = {46},
	number = {12},
	year = {2008},
	month = {2008 Dec},
	pages = {1019-30},
	abstract = {Plant annexins belong to a multigene family and are suggested to play a role in stress responses. A full-length cDNA for a gene encoding an annexin protein was isolated and characterized from Brassica juncea (AnnBj1). AnnBj1 message levels were regulated by abscisic acid, ethephon, salicylic acid, and methyl jasmonate as well as chemicals that induce osmotic stress (NaCl, Mannitol or PEG), heavy metal stress (CdCl(2)) and oxidative stress (methyl viologen or H(2)O(2)). In order to determine if AnnBj1 functions in protection against stress, we generated transgenic tobacco plants ectopically expressing AnnBj1 under the control of constitutive CaMV 35S promoter. The transgenic tobacco plants showed significant tolerance to dehydration (mannitol), salt (NaCl), heavy metal (CdCl(2)) and oxidative stress (H(2)O(2)) at the seedling stage and retained higher chlorophyll levels in response to the above stresses as determined in detached leaf senescence assays. The transgenic plants also showed decreased accumulation of thiobarbituric acid-reactive substances (TBARS) compared to wild-type plants in response to mannitol treatments in leaf disc assays. AnnBj1 recombinant protein exhibited low levels of peroxidase activity in vitro and transgenic plants showed increased total peroxidase activity. Additionally, the transgenic plants showed enhanced resistance to the oomycete pathogen, Phytophthora parasitica var. nicotianae, and increased message levels for several pathogenesis-related proteins. Our results demonstrate that ectopic expression of AnnBj1 in tobacco provides tolerance to a variety of abiotic and biotic stresses.},
	keywords = {Adaptation, Physiological, Annexins, Base Sequence, Brassica, Cloning, Molecular, DNA Primers, DNA, Complementary, Oxidative Stress, Peroxidases, Plants, Genetically Modified, Reverse Transcriptase Polymerase Chain Reaction, Tobacco},
	issn = {0981-9428},
	doi = {10.1016/j.plaphy.2008.07.006},
	author = {Jami, Sravan Kumar and Clark, Greg B and Turlapati, Swathi Anuradha and Handley, Craig and Roux, Stanley J and Kirti, Pulugurtha Bharadwaja}
}
@article {2930,
	title = {Gene expression changes induced by space flight in single-cells of the fern Ceratopteris richardii.},
	journal = {Planta},
	volume = {229},
	number = {1},
	year = {2008},
	month = {2008 Dec},
	pages = {151-9},
	abstract = {This work describes a rare high-throughput evaluation of gene expression changes induced by space flight in a single plant cell. The cell evaluated is the spore of the fern Ceratopteris richardii, which exhibits both perception and response to gravity. cDNA microarray and Q RT-PCR analysis of spores germinating in microgravity onboard NASA space shuttle flight STS-93 revealed changes in the mRNA expression of roughly 5\% of genes analyzed. These gene expression changes were compared with gene expression changes that occur during gravity perception and response in animal cells and multicellular plants. Our data contribute to a better understanding of the impact of space flight conditions, including microgravity, on cellular growth and development, and provide insights into the adaptive strategies of individual cells in response to these conditions.},
	keywords = {Animals, Arabidopsis, Down-Regulation, Gene Expression Regulation, Plant, Genes, Plant, Oligonucleotide Array Sequence Analysis, Peroxidase, Plant Proteins, Plant Roots, Pteridaceae, Reverse Transcriptase Polymerase Chain Reaction, Space Flight, Weightlessness},
	issn = {0032-0935},
	doi = {10.1007/s00425-008-0817-y},
	author = {Salmi, Mari L and Roux, Stanley J}
}
@article {2964,
	title = {Biochemical characterization of a family of proteins that stabilizes a plant Ran protein in its GTP-bound conformation.},
	journal = {Plant Physiol Biochem},
	volume = {45},
	number = {6-7},
	year = {2007},
	month = {2007 Jun-Jul},
	pages = {515-20},
	abstract = {Ran-binding proteins (RanBP) are a group of proteins that bind to Ran (Ras-related nuclear small G-protein) and thus control the GTP/GDP-bound states of the Ran and couple the Ran GTPase cycle to cellular processes. In an effort to identify potential downstream effectors for PsRan1-dependent cellular processes, we detected a group of pea Ran (PsRan1)-binding proteins and characterized their biochemical activities. A Ran overlay assay using [(32)P-GTP]-labeled PsRan1 revealed three PsRan1-binding proteins (33, 45, and 85kDa in size) from total protein extracts of dark-grown pea plumules. These proteins bound preferentially to the Ran-GTP over Ran-GDP conformation and subsequently stabilized its GTP-bound status. We propose that they are a family of proteins that maintain the Ran protein in the active conformation and are potential downstream mediators for PsRan1-dependent cellular processes. Our report provides the basis for characterizing and dissecting Ran downstream targets and Ran-mediated events, and it thus facilitates our understanding about the roles played by Ran/RanBP signaling pathways during plant growth and development.},
	keywords = {Edetic Acid, Guanosine Triphosphate, Kinetics, Peas, Plant Proteins, Polymerase Chain Reaction, Protein Binding, Protein Conformation, ran GTP-Binding Protein},
	issn = {0981-9428},
	doi = {10.1016/j.plaphy.2007.03.003},
	author = {Lee, Y and Roux, S J and Kim, S-H}
}
@article {2951,
	title = {Extracellular ATP: an unexpected role as a signaler in plants.},
	journal = {Trends Plant Sci},
	volume = {12},
	number = {11},
	year = {2007},
	month = {2007 Nov},
	pages = {522-7},
	abstract = {ATP and other nucleoside triphosphates not only drive energy-dependent reactions inside cells, but can also function outside the plasma membrane in the extracellular matrix, where they function as agonists that can induce diverse physiological responses without being hydrolyzed. This external role of ATP is well established in animal cells but only recently has it become apparent that extracellular ATP (eATP) can also function as a signaling agent in plants. Recent data have shown that eATP and other nucleotides can induce an increase in the cytosolic Ca(2+) concentration and diverse downstream changes that influence plant growth and defense responses. Ectoapyrase enzymes that regulate the eATP concentration also have an impact on plant growth. These results beg the question of whether there is a receptor that can bind to eATP and transduce this into signaling changes. Answering this will be key to understanding how eATP and ectoapyrases influence plant growth and development.},
	keywords = {Adenosine Triphosphate, Calcium, Cell Membrane, Plant Physiological Phenomena, Plant Roots, Receptors, Purinergic, Signal Transduction},
	issn = {1360-1385},
	doi = {10.1016/j.tplants.2007.09.003},
	author = {Roux, Stanley J and Steinebrunner, Iris}
}
@article {2936,
	title = {Apyrases (nucleoside triphosphate-diphosphohydrolases) play a key role in growth control in Arabidopsis.},
	journal = {Plant Physiol},
	volume = {144},
	number = {2},
	year = {2007},
	month = {2007 Jun},
	pages = {961-75},
	abstract = {Expression of two Arabidopsis (Arabidopsis thaliana) apyrase (nucleoside triphosphate-diphosphohydrolase) genes with high similarity, APY1 and APY2, was analyzed during seedling development and under different light treatments using beta-glucuronidase fusion constructs with the promoters of both genes. As evaluated by beta-glucuronidase staining and independently confirmed by other methods, the highest expression of both apyrases was in rapidly growing tissues and/or tissues that accumulate high auxin levels. Red-light treatment of etiolated seedlings suppressed the protein and message level of both apyrases at least as rapidly as it inhibited hypocotyl growth. Adult apy1 and apy2 single mutants had near-normal growth, but apy1apy2 double-knockout plants were dwarf, due primarily to reduced cell elongation. Pollen tubes and etiolated hypocotyls overexpressing an apyrase had faster growth rates than wild-type plants. Growing pollen tubes released ATP into the growth medium and suppression of apyrase activity by antiapyrase antibodies or by inhibitors simultaneously increased medium ATP levels and inhibited pollen tube growth. These results imply that APY1 and APY2, like their homologs in animals, act to reduce the concentration of extracellular nucleotides, and that this function is important for the regulation of growth in Arabidopsis.},
	keywords = {Adenosine Triphosphate, Antibodies, Apyrase, Arabidopsis, Cell Growth Processes, Down-Regulation, Extracellular Space, Gene Expression, Hypocotyl, Light, Plant Roots, Pollen Tube},
	issn = {0032-0889},
	doi = {10.1104/pp.107.097568},
	author = {Wu, Jian and Steinebrunner, Iris and Sun, Yu and Butterfield, Timothy and Torres, Jonathan and Arnold, David and Gonzalez, Antonio and Jacob, Francis and Reichler, Stuart and Roux, Stanley J}
}
@article {2920,
	title = {Conserved features of germination and polarized cell growth: a few insights from a pollen-fern spore comparison.},
	journal = {Ann Bot},
	volume = {99},
	number = {1},
	year = {2007},
	month = {2007 Jan},
	pages = {9-17},
	abstract = {BACKGROUND: The germination of both pollen and fern spores results in the emergence of a cell-pollen tube from pollen, rhizoid from spore-that grows in a polar fashion, primarily at its apical end. In both of these tip-growing cells, the delivery of secretory vesicles to the growing end is guided in part by a calcium gradient, with calcium entering at the tip where it is most highly concentrated. The similarities between the two systems extend beyond tip-focused calcium gradients to encompass signalling pathways and elements including calmodulin, nitric oxide, annexins and Rop-GTPases.

SCOPE AND AIMS: This review is limited to those pathways and elements that function similarly in fern and pollen systems based on currently available evidence. The aim is to illustrate the common mechanisms by which tip growth occurs, facilitate further investigations into this area, and examine the implications for the evolutionarily conserved control of tip growth.

CONCLUSIONS: The interplay of calcium, nitric oxide and other effectors in both pollen and fern spores suggests certain signalling pathways became important regulators of germination and growth early in the evolution of land plants. Both large- and small-scale comparative genomic methods have shown to be promising in their ability to find new and relevant comparisons for further research. Cross-species comparisons may serve to speed up this process by highlighting both basic pathways and system-specific deviations.},
	keywords = {Arabidopsis, Calcium, Cell Polarity, Ferns, Gene Expression, Germination, Nitric Oxide, Pollen Tube, Spores},
	issn = {0305-7364},
	doi = {10.1093/aob/mcl159},
	author = {Bushart, Thomas J and Roux, Stanley J}
}
@article {2923,
	title = {Nitric oxide and cGMP signaling in calcium-dependent development of cell polarity in Ceratopteris richardii.},
	journal = {Plant Physiol},
	volume = {144},
	number = {1},
	year = {2007},
	month = {2007 May},
	pages = {94-104},
	abstract = {Single-celled spores of the fern Ceratopteris richardii undergo gravity-directed cell polarity development that is driven by polar calcium currents. Here we present results that establish a role for nitric oxide (NO)/cGMP signaling in transducing the stimulus of gravity to directed polarization of the spores. Application of specific NO donors and scavengers inhibited the calcium-dependent gravity response in a dose-dependent manner. The effects of NO donor exposure were antagonized by application of NO scavenger compounds. Similarly, the guanylate cyclase inhibitors 6-anilino-5,8-quinolinedione and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin, and the phosphodiesterase inhibitor Viagra, which modulate NO-dependent cGMP levels in the cells, disrupted gravity-directed cell polarity in a dose-dependent manner. Viagra effects were antagonized by application of NO scavengers, consistent with the postulate that NO and cGMP are linked in the signaling pathway. To identify other components of the signaling system we analyzed gene expression changes induced by Viagra treatment using microarrays and quantitative real-time reverse transcription-polymerase chain reaction. Preliminary microarray analysis revealed several genes whose expression was significantly altered by Viagra treatment. Three of these genes had strong sequence similarity to key signal transduction or stress response genes and quantitative real-time reverse transcription-polymerase chain reaction was used to more rigorously quantify the effects of Viagra on their expression in spores and to test how closely these effects could be mimicked by treatment with dibutyryl cGMP. Taken together our results implicate NO and cGMP as downstream effectors that help link the gravity stimulus to polarized growth in C. richardii spores. Sequence data from this article can be found in the GenBank/EMBL data libraries under accession numbers BE 640669 to BE 643506, BQ 086920 to BQ 087668, and CV 734654 to CV 736151.},
	keywords = {Aminoquinolines, Calcium, Cell Polarity, Cyclic GMP, Dibutyryl Cyclic GMP, Guanylate Cyclase, Molecular Sequence Data, Nitric Oxide, Nitric Oxide Donors, Phosphodiesterase Inhibitors, Piperazines, Pteridaceae, Purines, Reverse Transcriptase Polymerase Chain Reaction, Rotation, Signal Transduction, Spores, Sulfones},
	issn = {0032-0889},
	doi = {10.1104/pp.107.096131},
	author = {Salmi, Mari L and Morris, Kacey E and Roux, Stanley J and Porterfield, D Marshall}
}
@article {2965,
	title = {Expression profiling of the Arabidopsis annexin gene family during germination, de-etiolation and abiotic stress.},
	journal = {Plant Physiol Biochem},
	volume = {44},
	number = {1},
	year = {2006},
	month = {2006 Jan},
	pages = {13-24},
	abstract = {Annexins are a multigene family in most plant species and are suggested to play a role in a wide variety of essential cellular processes. In Arabidopsis thaliana there are eight different annexins (AnnAt1-8), which range from 29\% to 83\% in deduced amino acid sequence identity. As a first step toward clarifying the individual functions of these annexins, in this study we have used quantitative real time reverse transcription PCR to assess their differential expression in different tissues or after different stimuli. We determined which annexins are expressed during germination and early seedling growth by assaying annexin expression levels in dry and germinating seeds and in 7-day-old light-grown seedlings. Our results indicate that transcripts for all eight annexins are present in germinating seeds and that transcript levels for all the annexins increase by 7 days of normal growth. We assayed transcript levels in dark grown roots, cotyledons, and hypocotyls and found that the relative abundance of each annexin varied in these dark-grown tissues. We also examined the effects of red and far red light treatments on annexin expression in 5.5-day-old etiolated seedlings. Light treatments significantly altered transcript levels in hypocotyls and cotyledons for only two members of the gene family. Finally, we monitored annexin expression changes in response to a variety of abiotic stresses. We found that the expression of most of the Arabidopsis annexin genes is differentially regulated by exposure to salt, drought, and high- and low-temperature conditions, indicating a likely role for members of this gene family in stress responses.},
	keywords = {Amino Acid Sequence, Annexins, Arabidopsis, Arabidopsis Proteins, Cotyledon, Gene Expression Profiling, Germination, Heating, Hypocotyl, Molecular Sequence Data, Phylogeny, Plant Roots, Reverse Transcriptase Polymerase Chain Reaction, Seeds, Sodium Chloride, Dietary},
	issn = {0981-9428},
	doi = {10.1016/j.plaphy.2006.02.002},
	author = {Cantero, A and Barthakur, S and Bushart, T J and Chou, S and Morgan, R O and Fernandez, M P and Clark, G B and Roux, S J}
}
@article {2953,
	title = {Plant responses to extracellular nucleotides: Cellular processes and biological effects.},
	journal = {Purinergic Signal},
	volume = {2},
	number = {3},
	year = {2006},
	month = {2006 Sep},
	pages = {443-9},
	abstract = {Higher plants exhibit cellular responsiveness to the exogenous application of purine nucleotides in a manner consistent with a cell-cell signaling function for these molecules. Like animals, plants respond to extracellular ATP, ADP, and stable analogues (e.g., ATPgammaS and ADPbetaS) by increasing the cytoplasmic concentration of calcium. Agonist substrate specificity and concentration dependency suggest receptor mediation of these events, and, although the identity of the plant receptor is currently unknown, pharmacological analysis points to the involvement of a plasma membrane-localized calcium channel. Extracellular ATP can also induce the production of reactive oxygen species and stimulate an increase in the mRNA levels of a number of stress- and calcium-regulated genes, suggesting a role for nucleotide-based signaling in plant wound and defense responses. Furthermore, the growth and development of plants can also be altered by the application of external ATP. Recent studies are only beginning to uncover the complexities of plant signaling networks activated in response to extracellular ATP and how these might interact to affect plant physiological processes.},
	issn = {1573-9538},
	doi = {10.1007/s11302-005-3981-6},
	author = {Jeter, Collene R and Roux, Stanley J}
}
@article {2946,
	title = {Extracellular ATP induces the accumulation of superoxide via NADPH oxidases in Arabidopsis.},
	journal = {Plant Physiol},
	volume = {140},
	number = {4},
	year = {2006},
	month = {2006 Apr},
	pages = {1222-32},
	abstract = {Extracellular ATP can serve as a signaling agent in animal cells, and, as suggested by recent reports, may also do so in plant cells. In animal cells it induces the production of reactive oxygen species through the mediation of NADPH oxidase. Similarly, here we report that in leaves of Arabidopsis (Arabidopsis thaliana), applied ATP, but not AMP or phosphate, induces the accumulation of superoxide (O2-) in a biphasic, dose-dependent manner, with a threshold at 500 nm ATP. This effect did not require ATP hydrolysis for it was mimicked by ATPgammaS. ATP also induced increased levels of Arabidopsis respiratory burst oxidase homolog D (AtrbohD) mRNA, but ATP-treated plants that had disrupted AtrbohD and AtrbohF genes did not accumulate O2-, indicating that NADPH oxidases are responsible for the induced O2- accumulation. Inhibitors of mammalian P2-type ATP receptors abolished ATP-induced O2- production, suggesting that the ATP effects may be mediated through P2-like receptors in plants. Cytosolic Ca2+ and calmodulin are likely to help transduce the ATP responses, as they do in animal cells, because a Ca2+ channel blocker, a Ca2+ chelator, and calmodulin antagonist all reduced ATP-induced O2- accumulation. Furthermore, ATP treatment enhanced the expression of genes that are induced by wounds and other stresses. The ATP measured at wound sites averaged 40 microm, well above the level needed to induce O2- accumulation and gene expression changes. Transgenic plants overexpressing an apyrase gene had reduced O2- production in response to applied ATP and wounding. Together, these data suggest a possible role for extracellular ATP as a signal potentially in wound and stress responses.},
	keywords = {Adenosine Triphosphate, Apyrase, Arabidopsis, Calcium, Gene Expression Regulation, Plant, Models, Biological, Molecular Sequence Data, NADPH Oxidase, Nucleotides, Plant Leaves, Purinergic P2 Receptor Antagonists, Reactive Oxygen Species, Signal Transduction, Superoxides},
	issn = {0032-0889},
	doi = {10.1104/pp.105.073072},
	author = {Song, Charlotte J and Steinebrunner, Iris and Wang, Xuanzhi and Stout, Stephen C and Roux, Stanley J}
}
@article {2945,
	title = {Secretion as a key component of gravitropic growth: implications for annexin involvement in differential growth.},
	journal = {Gravit Space Biol Bull},
	volume = {18},
	number = {2},
	year = {2005},
	month = {2005 Jun},
	pages = {113-4},
	keywords = {Annexins, Arabidopsis, Cell Wall, DNA, Bacterial, DNA, Single-Stranded, Gravitation, Gravitropism, Hypocotyl, Plant Epidermis, Plant Growth Regulators, Plant Roots, Polysaccharides},
	issn = {1089-988X},
	author = {Clark, Greg and Cantero-Garcia, Araceli and Butterfield, Tim and Dauwalder, Marianne and Roux, Stanley J}
}
@article {2928,
	title = {Immunolocalization and histochemical evidence for the association of two different Arabidopsis annexins with secretion during early seedling growth and development.},
	journal = {Planta},
	volume = {220},
	number = {4},
	year = {2005},
	month = {2005 Feb},
	pages = {621-31},
	abstract = {Annexins are a multigene, multifunctional family of calcium-dependent, membrane-binding proteins found in animal and plant cells. In plants, annexins have been localized in the cytoplasm and at the cell periphery of highly secretory cell types, and in the tip region of polarly growing cells. Consequently, one proposed function for annexins in plant cells is participation in the Golgi-mediated secretion of new wall materials. In Arabidopsis, there are eight different annexin cDNAs, which share between 30\% and 81\% deduced amino acid sequence identity. We have used two monospecific Arabidopsis anti-annexin antibodies, raised against divergent 31-mer peptides from AnnAt1 and AnnAt2 and a previously characterized pea anti-annexin p35 antibody, for Western blot and immunolocalization studies in Arabidopsis. Western blot analyses of various Arabidopsis protein fractions showed that the two Arabidopsis antibodies are able to specifically recognize annexins in both soluble and membrane fractions. Immunofluorescence results with the three annexin antibodies show staining of secretory cells, especially at the cell periphery in developing sieve tubes, outer root cap cells, and in root hairs, consistent with previous results. In developmentally different stages some staining was also seen near the apical meristem, in some leaf cells, and in phloem-associated cells. Autoradiography following 3H-galactose incorporation was used to more clearly correlate active secretion of wall materials with the localization patterns of a specific individual annexin protein in the same cells at the same developmental stage. The results obtained in this study provide further support for the hypothesis that these two Arabidopsis annexins function in Golgi-mediated secretion during early seedling growth and development.},
	keywords = {Amino Acid Sequence, Annexins, Arabidopsis, Arabidopsis Proteins, Seedling, Sequence Alignment, Sequence Homology, Amino Acid},
	issn = {0032-0935},
	doi = {10.1007/s00425-004-1374-7},
	author = {Clark, Gregory B and Lee, Dongwoo and Dauwalder, Marianne and Roux, Stanley J}
}
@article {2921,
	title = {Profile and analysis of gene expression changes during early development in germinating spores of Ceratopteris richardii.},
	journal = {Plant Physiol},
	volume = {138},
	number = {3},
	year = {2005},
	month = {2005 Jul},
	pages = {1734-45},
	abstract = {Analysis of an expressed sequence tag library with more than 5,000 sequences from spores of the fern Ceratopteris richardii reveals that more than 3,900 of them represent distinct genes, and almost 70\% of these have significant similarity to Arabidopsis (Arabidopsis thaliana) genes. Eight genes are common between three very different dormant plant systems, Ceratopteris spores, Arabidopsis seeds, and Arabidopsis pollen. We evaluated the pattern of mRNA abundance over the first 48 h of spore development using a microarray of cDNAs representing 3,207 distinct genes of C. richardii and determined the relative levels of RNA abundance for 3,143 of these genes using a Bayesian method of statistical analysis. More than 900 of them (29\%) show a significant change between any of the five time points analyzed, and these have been annotated based on their sequence similarity with the Arabidopsis proteome. Novel data arising from these analyses identify genes likely to be critical for the germination and subsequent early development of diverse cells and tissues emerging from dormancy.},
	keywords = {Arabidopsis, Gene Expression Profiling, Gene Expression Regulation, Plant, Genes, Plant, Germination, Oligonucleotide Array Sequence Analysis, Plant Proteins, Pollen, Pteridaceae, Reverse Transcriptase Polymerase Chain Reaction, Seeds, Spores},
	issn = {0032-0889},
	doi = {10.1104/pp.105.062851},
	author = {Salmi, Mari L and Bushart, Thomas J and Stout, Stephen C and Roux, Stanley J}
}
@article {2932,
	title = {Evidence of a novel cell signaling role for extracellular adenosine triphosphates and diphosphates in Arabidopsis.},
	journal = {Plant Cell},
	volume = {16},
	number = {10},
	year = {2004},
	month = {2004 Oct},
	pages = {2652-64},
	abstract = {Extracellular ATP is a known receptor agonist in animals and was previously shown to alter plant growth, and so we investigated whether ATP derivatives could function outside plant cells as signaling agents. Signaling responses induced by exogenous nucleotides in animal cells typically include increases in free cytoplasmic calcium concentration ([Ca(2+)](cyt)). We have evaluated the ability of exogenously applied adenosine 5{\textquoteright}-[gamma-thio]triphosphate (ATPgammaS), adenosine 5{\textquoteright}-[beta-thio]diphosphate (ADPbetaS), and adenosine 5{\textquoteright}-O-thiomonophosphate to alter [Ca(2+)](cyt) in intact apoaequorin transgenic Arabidopsis thaliana seedlings. ATPgammaS and ADPbetaS increase [Ca(2+)](cyt), and this increase is enhanced further when the nucleotides are added with the elicitor oligogalacturonic acid. Exogenous treatment with ATP also increases the level of transcripts encoding mitogen-activated protein kinases and proteins involved in ethylene biosynthesis and signal transduction. The increase in [Ca(2+)](cyt) induced by nucleotide derivatives can be ablated by Ca(2+)-channel blocking agents and by the calcium chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N{\textquoteright},N{\textquoteright}-tetraacetic acid (BAPTA), and the changes in gene expression can be partially blocked by these agents. These observations suggest that extracellular ATP can activate calcium-mediated cell-signaling pathways in plants, potentially playing a physiological role in transducing stress and wound responses.},
	keywords = {Adenosine Diphosphate, Adenosine Triphosphate, Arabidopsis, Gene Expression Profiling, Molecular Sequence Data, Signal Transduction},
	issn = {1040-4651},
	doi = {10.1105/tpc.104.023945},
	author = {Jeter, Collene R and Tang, Wenqiang and Henaff, Elizabeth and Butterfield, Tim and Roux, Stanley J}
}
@article {2927,
	title = {Biochemical and immunological characterization of pea nuclear intermediate filament proteins.},
	journal = {Planta},
	volume = {218},
	number = {6},
	year = {2004},
	month = {2004 Apr},
	pages = {965-75},
	abstract = {In immunoblot assays, at least three putative nuclear intermediate filament (NIF) proteins were detected in nuclear envelope-matrix (NEM) and lamin (L1) fractions of nuclei from plumules of dark-grown pea (Pisum sativum L.) seedlings. These NIF proteins had apparent molecular masses of ca. 65, 60, and 54 kDa (also referred to as p65, p60, and p54), and appeared as multiple isoelectric forms, with pIs ranging from ca. 4.8 to 6.0. Polyclonal and monoclonal antibodies were raised to the 65-kDa NIF protein bands excised from gels after electrophoresis. These anti-pea antibodies were specifically cross-reactive with the pea nuclear p65, p60, and p54 proteins and also with chicken lamins. Sequence alignment of peptide fragments obtained from the 65- and 60-kDa pea NIF proteins showed similarity with animal intermediate filament proteins such as lamins and keratins and with certain plant proteins predicted to have long coiled-coil domains. These pea NIF proteins were further purified and enriched from the NEM fraction using methods similar to those used for isolating animal lamins. When negatively stained and viewed by transmission electron microscopy, the filaments in the pea lamin (L1) fraction appeared to be 6-12 nm in diameter. As assayed by immunofluorescence cytochemistry using a confocal laser-scanning microscope, fixed pea plumule cells displayed uniform as opposed to peripheral nuclear staining by several of the antibody preparations, both polyclonal and monoclonal. This report describes the biochemical and immunological properties of these pea NIF proteins.},
	keywords = {Amino Acid Sequence, Antibodies, Monoclonal, Antibody Specificity, Intermediate Filament Proteins, Microscopy, Electron, Molecular Sequence Data, Nuclear Envelope, Peas, Plant Proteins, Sequence Alignment, Sequence Homology, Amino Acid},
	issn = {0032-0935},
	doi = {10.1007/s00425-003-1182-5},
	author = {Blumenthal, Sonal S D and Clark, Gregory B and Roux, Stanley J}
}
@article {2959,
	title = {Extracellular ATP inhibits root gravitropism at concentrations that inhibit polar auxin transport.},
	journal = {Plant Physiol},
	volume = {131},
	number = {1},
	year = {2003},
	month = {2003 Jan},
	pages = {147-54},
	abstract = {Raising the level of extracellular ATP to mM concentrations similar to those found inside cells can block gravitropism of Arabidopsis roots. When plants are grown in Murashige and Skoog medium supplied with 1 mM ATP, their roots grow horizontally instead of growing straight down. Medium with 2 mM ATP induces root curling, and 3 mM ATP stimulates lateral root growth. When plants are transferred to medium containing exogenous ATP, the gravity response is reduced or in some cases completely blocked by ATP. Equivalent concentrations of ADP or inorganic phosphate have slight but usually statistically insignificant effects, suggesting the specificity of ATP in these responses. The ATP effects may be attributable to the disturbance of auxin distribution in roots by exogenously applied ATP, because extracellular ATP can alter the pattern of auxin-induced gene expression in DR5-beta-glucuronidase transgenic plants and increase the response sensitivity of plant roots to exogenously added auxin. The presence of extracellular ATP also decreases basipetal auxin transport in a dose-dependent fashion in both maize (Zea mays) and Arabidopsis roots and increases the retention of [(3)H]indole-3-acetic acid in root tips of maize. Taken together, these results suggest that the inhibitory effects of extracellular ATP on auxin distribution may happen at the level of auxin export. The potential role of the trans-plasma membrane ATP gradient in auxin export and plant root gravitropism is discussed.},
	keywords = {Adenosine Triphosphate, Arabidopsis, Biological Transport, Dose-Response Relationship, Drug, Extracellular Space, Glucuronidase, Gravitropism, Indoleacetic Acids, Naphthaleneacetic Acids, Plant Roots, Plants, Genetically Modified, Zea mays},
	issn = {0032-0889},
	doi = {10.1104/pp.013672},
	author = {Tang, Wenqiang and Brady, Shari R and Sun, Yu and Muday, Gloria K and Roux, Stanley J}
}
@article {2952,
	title = {An Arabidopsis Ran-binding protein, AtRanBP1c, is a co-activator of Ran GTPase-activating protein and requires the C-terminus for its cytoplasmic localization.},
	journal = {Planta},
	volume = {216},
	number = {6},
	year = {2003},
	month = {2003 Apr},
	pages = {1047-52},
	abstract = {Ran-binding proteins (RanBPs) are a group of proteins that bind to Ran (Ras-related nuclear small GTP-binding protein), and thus either control the GTP/GDP-bound states of Ran or help couple the Ran GTPase cycle to a cellular process. AtRanBP1c is a Ran-binding protein from Arabidopsis thaliana (L.) Heynh. that was recently shown to be critically involved in the regulation of auxin-induced mitotic progression [S.-H. Kim et al. (2001) Plant Cell 13:2619-2630]. Here we report that AtRanBP1c inhibits the EDTA-induced release of GTP from Ran and serves as a co-activator of Ran-GTPase-activating protein (RanGAP) in vitro. Transient expression of AtRanBP1c fused to a beta-glucuronidase (GUS) reporter reveals that the protein localizes primarily to the cytosol. Neither the N- nor C-terminus of AtRanBP1c, which flank the Ran-binding domain (RanBD), is necessary for the binding of PsRan1-GTP to the protein, but both are needed for the cytosolic localization of GUS-fused AtRanBP1c. These findings, together with a previous report that AtRanBP1c is critically involved in root growth and development, imply that the promotion of GTP hydrolysis by the Ran/RanGAP/AtRanBP1c complex in the cytoplasm, and the resulting concentration gradient of Ran-GDP to Ran-GTP across the nuclear membrane could be important in the regulation of auxin-induced mitotic progression in root tips of A. thaliana.},
	keywords = {Arabidopsis, Arabidopsis Proteins, Cytoplasm, Edetic Acid, Enzyme Induction, Gene Expression Regulation, Plant, GTPase-Activating Proteins, Guanosine Triphosphate, Nuclear Proteins, Protein Structure, Tertiary, Protein Transport, ran GTP-Binding Protein, Time Factors},
	issn = {0032-0935},
	doi = {10.1007/s00425-002-0959-2},
	author = {Kim, Soo-Hwan and Roux, Stanley J}
}
@article {2954,
	title = {Multiherbicide tolerance conferred by AtPgp1 and apyrase overexpression in Arabidopsis thaliana.},
	journal = {Nat Biotechnol},
	volume = {21},
	number = {4},
	year = {2003},
	month = {2003 Apr},
	pages = {428-33},
	abstract = {Herbicide resistance is an important trait often introduced into crop plants. Mechanisms of resistance can involve a mutant target protein that is unaffected by the herbicide, or metabolic detoxification or degradation of the herbicide. Recently, we showed that overexpression in Arabidopsis thaliana of either psNTP9, the garden pea apyrase gene, or AtPgp1, the A. thaliana homolog of the plant multidrug resistance (MDR) gene, enabled A. thaliana to germinate on the toxin cycloheximide and to grow better on toxic levels of the plant hormone N6-[2-isopentyl]adenine (2iP). Here we report that overexpression of either MDR or apyrase proteins resulted in increased resistance to herbicides from different chemical classes. Apyrase inhibition by small molecule inhibitors reversed this resistance. Treatment of untransformed plants with an apyrase inhibitor increased their sensitivity to the same herbicides. These results indicate that the genes may be involved in a resistance mechanism relating to decreased retention or increased active efflux of herbicide from the plant cell.},
	keywords = {Apyrase, Arabidopsis, Arabidopsis Proteins, ATP-Binding Cassette Transporters, Drug Tolerance, Gene Expression Regulation, Plant, Herbicides, P-Glycoproteins, Plants, Genetically Modified, Transformation, Genetic},
	issn = {1087-0156},
	doi = {10.1038/nbt809},
	author = {Windsor, Brian and Roux, Stanley J and Lloyd, Alan}
}
@article {2948,
	title = {Disruption of apyrases inhibits pollen germination in Arabidopsis.},
	journal = {Plant Physiol},
	volume = {131},
	number = {4},
	year = {2003},
	month = {2003 Apr},
	pages = {1638-47},
	abstract = {In Arabidopsis, we previously identified two highly similar apyrases, AtAPY1 and AtAPY2. Here, T-DNA knockout (KO) mutations of each gene were isolated in a reverse genetic approach. The single KO mutants lacked a discernible phenotype. The double KO mutants, however, exhibited a complete inhibition of pollen germination, and this correlated with positive beta-glucuronidase staining in the pollen of apyrase promoter:beta-glucuronidase fusion transgenic lines. The vast majority of the pollen grains of these mutants were identical to wild type in size, shape, and nuclear state and were viable as assayed by metabolic activity and plasma membrane integrity. Complementation with either AtAPY1 or AtAPY2 cDNA rescued pollen germination, confirming that the phenotype was apyrase specific. Despite the redundancy of the two apyrases in rescue potential, transmission analyses suggested a greater role for AtAPY2 in male gamete success. The effect of mutant apyrase on the transmission through the female gametophyte was only marginal, and embryo development appeared normal in the absence of apyrases. The male-specific double KO mutation is fully penetrant and shows that apyrases play a crucial role in pollen germination.},
	keywords = {Apyrase, Arabidopsis, Arabidopsis Proteins, DNA, Bacterial, Gene Deletion, Germination, Homozygote, Mutagenesis, Insertional, Mutation, Phenotype, Pollen, Promoter Regions, Genetic},
	issn = {0032-0889},
	doi = {10.1104/pp.102.014308},
	author = {Steinebrunner, Iris and Wu, Jian and Sun, Yu and Corbett, Ashley and Roux, Stanley J}
}
@article {2933,
	title = {Early development of fern gametophytes in microgravity.},
	journal = {Adv Space Res},
	volume = {31},
	number = {1},
	year = {2003},
	month = {2003},
	pages = {215-20},
	abstract = {Dormant spores of the fern Ceratopteris richardii were flown on Shuttle mission STS-93 to evaluate the effects of micro-g on their development and on their pattern of gene expression. Prior to flight the spores were sterilized and sown into one of two environments: (1) Microscope slides in a video-microscopy module; and (2) Petri dishes. All spores were then stored in darkness until use. Spore germination was initiated on orbit after exposure to light. For the spores on microscope slides, cell level changes were recorded through the clear spore coat of the spores by video microscopy. After their exposure to light, spores in petri dishes were frozen in orbit at four different time points during which on earth gravity fixes the polarity of their development. Spores were then stored frozen in Biological Research in Canister units until recovery on earth. The RNAs from these cells and from 1-g control cells were extracted and analyzed on earth after flight to assay changes in gene expression. Video microscopy results revealed that the germinated spores developed normally in microgravity, although the polarity of their development, which is guided by gravity on earth, was random in space. Differential Display-PCR analyses of RNA extracted from space-flown cells showed that there was about a 5\% change in the pattern of gene expression between cells developing in micro-g compared to those developing on earth.},
	keywords = {Cell Nucleus, Cell Polarity, Equipment Design, Ferns, Gene Expression, Germination, Microscopy, Video, RNA, Plant, Space Flight, Spores, Weightlessness},
	issn = {0273-1177},
	author = {Roux, Stanley J and Chatterjee, Ani and Hillier, Sheila and Cannon, Tom}
}
@article {2925,
	title = {Rapid and efficient suppression of gene expression in a single-cell model system, Ceratopteris richardii.},
	journal = {Plant Physiol},
	volume = {131},
	number = {3},
	year = {2003},
	month = {2003 Mar},
	pages = {1165-8},
	keywords = {Culture Techniques, Expressed Sequence Tags, Ferns, Gene Expression Regulation, Plant, Light, Molecular Sequence Data, RNA Interference, RNA, Small Interfering, RNA-Induced Silencing Complex, Signal Transduction, Spores},
	issn = {0032-0889},
	doi = {10.1104/pp.016949},
	author = {Stout, Stephen C and Clark, Gregory B and Archer-Evans, Sarah and Roux, Stanley J}
}
@article {2966,
	title = {Automated colorimetric screen for apyrase inhibitors.},
	journal = {Biotechniques},
	volume = {33},
	number = {5},
	year = {2002},
	month = {2002 Nov},
	pages = {1024, 1026, 1028-30},
	abstract = {Apyrases are enzymes that efficiently hydrolyze ATP and ADP and may operate both inside and outside the cell. Although apyrases are important to a variety of cellular mechanisms and uses in industry, there are no available apyrase-specific inhibitors. Colorimetric assays based on the Fiske-Subbarow method for measuring inorganic phosphate are able to detect the release of inorganic phosphate from ATP and other nucleotides. We found that this type of assay could be automated and used to screen for apyrase-inhibiting compounds by assaying for a reduction in released phosphate in the presence of potential inhibitors. The automation of this assay allowed for the successful screening of a commercially available compound library. Several low molecular weight compounds were identified that, when used at micromolar concentrations, effectively inhibited apyrase activity.},
	keywords = {Apyrase, Automation, Colorimetry, Enzyme Inhibitors, Kinetics, Molecular Weight, Phosphates, Plant Proteins, Solanum tuberosum},
	issn = {0736-6205},
	author = {Windsor, J B and Thomas, C and Hurley, L and Roux, S J and Lloyd, A M}
}
@article {2974,
	title = {Differential expression of members of the annexin multigene family in Arabidopsis.},
	journal = {Plant Physiol},
	volume = {126},
	number = {3},
	year = {2001},
	month = {2001 Jul},
	pages = {1072-84},
	abstract = {Although in most plant species no more than two annexin genes have been reported to date, seven annexin homologs have been identified in Arabidopsis, Annexin Arabidopsis 1-7 (AnnAt1--AnnAt7). This establishes that annexins can be a diverse, multigene protein family in a single plant species. Here we compare and analyze these seven annexin gene sequences and present the in situ RNA localization patterns of two of these genes, AnnAt1 and AnnAt2, during different stages of Arabidopsis development. Sequence analysis of AnnAt1--AnnAt7 reveals that they contain the characteristic four structural repeats including the more highly conserved 17-amino acid endonexin fold region found in vertebrate annexins. Alignment comparisons show that there are differences within the repeat regions that may have functional importance. To assess the relative level of expression in various tissues, reverse transcription-PCR was carried out using gene-specific primers for each of the Arabidopsis annexin genes. In addition, northern blot analysis using gene-specific probes indicates differences in AnnAt1 and AnnAt2 expression levels in different tissues. AnnAt1 is expressed in all tissues examined and is most abundant in stems, whereas AnnAt2 is expressed mainly in root tissue and to a lesser extent in stems and flowers. In situ RNA localization demonstrates that these two annexin genes display developmentally regulated tissue-specific and cell-specific expression patterns. These patterns are both distinct and overlapping. The developmental expression patterns for both annexins provide further support for the hypothesis that annexins are involved in the Golgi-mediated secretion of polysaccharides.},
	keywords = {Amino Acid Sequence, Annexins, Arabidopsis, Blotting, Northern, Cloning, Molecular, DNA, Complementary, DNA, Plant, Gene Expression Profiling, In Situ Hybridization, Molecular Sequence Data, Multigene Family, Reverse Transcriptase Polymerase Chain Reaction, Sequence Alignment},
	issn = {0032-0889},
	author = {Clark, G B and Sessions, A and Eastburn, D J and Roux, S J}
}
@article {2976,
	title = {Light differentially regulates cell division and the mRNA abundance of pea nucleolin during de-etiolation.},
	journal = {Plant Physiol},
	volume = {125},
	number = {1},
	year = {2001},
	month = {2001 Jan},
	pages = {339-50},
	abstract = {The abundance of plant nucleolin mRNA is regulated during de-etiolation by phytochrome. A close correlation between the mRNA abundance of nucleolin and mitosis has also been previously reported. These results raised the question of whether the effects of light on nucleolin mRNA expression were a consequence of light effects on mitosis. To test this we compared the kinetics of light-mediated increases in cell proliferation with that of light-mediated changes in the abundance of nucleolin mRNA using plumules of dark-grown pea (Pisum sativum) seedlings. These experiments show that S-phase increases 9 h after a red light pulse, followed by M-phase increases in the plumule leaves at 12 h post-irradiation, a time course consistent with separately measured kinetics of red light-induced increases in the expression of cell cycle-regulated genes. These increases in cell cycle-regulated genes are photoreversible, implying that the light-induced increases in cell proliferation are, like nucleolin mRNA expression, regulated via phytochrome. Red light stimulates increases in the mRNA for nucleolin at 6 h post-irradiation, prior to any cell proliferation changes and concurrent with the reported timing of phytochrome-mediated increases of rRNA abundance. After a green light pulse, nucleolin mRNA levels increase without increasing S-phase or M-phase. Studies in animals and yeast indicate that nucleolin plays a significant role in ribosome biosynthesis. Consistent with this function, pea nucleolin can rescue nucleolin deletion mutants of yeast that are defective in rRNA synthesis. Our data show that during de-etiolation, the increased expression of nucleolin mRNA is more directly regulated by light than by mitosis.},
	keywords = {Cell Cycle, Cell Division, Darkness, Gene Expression Regulation, Plant, Kinetics, Light, Mitosis, Peas, Phosphoproteins, RNA, Messenger, RNA-Binding Proteins, S Phase},
	issn = {0032-0889},
	author = {Reichler, S A and Balk, J and Brown, M E and Woodruff, K and Clark, G B and Roux, S J}
}
@article {2975,
	title = {Wounding characteristics of glaser safety ammunition: a report of three cases.},
	journal = {J Forensic Sci},
	volume = {46},
	number = {1},
	year = {2001},
	month = {2001 Jan},
	pages = {160-4},
	abstract = {Handgun ammunition that contains multiple pellets (birdshot) comes in two forms. We describe here the autopsy and radiographic findings in three individuals who were fatally wounded with Glaser safety ammunition and contrast the findings to those reported in shot shell injuries.},
	keywords = {Adult, Autopsy, Female, Firearms, Forensic Medicine, Humans, Male, Middle Aged, Wounds, Gunshot},
	issn = {0022-1198},
	author = {de Roux, S J and Prendergast, N C and Tamburri, R}
}
@article {2968,
	title = {Antisense expression of an Arabidopsis ran binding protein renders transgenic roots hypersensitive to auxin and alters auxin-induced root growth and development by arresting mitotic progress.},
	journal = {Plant Cell},
	volume = {13},
	number = {12},
	year = {2001},
	month = {2001 Dec},
	pages = {2619-30},
	abstract = {We cloned a cDNA encoding an Arabidopsis Ran binding protein, AtRanBP1c, and generated transgenic Arabidopsis expressing the antisense strand of the AtRanBP1c gene to understand the in vivo functions of the Ran/RanBP signal pathway. The transgenic plants showed enhanced primary root growth but suppressed growth of lateral roots. Auxin significantly increased lateral root initiation and inhibited primary root growth in the transformants at 10 pM, several orders of magnitude lower than required to induce these responses in wild-type roots. This induction was followed by a blockage of mitosis in both newly emerged lateral roots and in the primary root, ultimately resulting in the selective death of cells in the tips of both lateral and primary roots. Given the established role of Ran binding proteins in the transport of proteins into the nucleus, these findings are consistent with a model in which AtRanBP1c plays a key role in the nuclear delivery of proteins that suppress auxin action and that regulate mitotic progress in root tips.},
	keywords = {Amino Acid Sequence, Apoptosis, Arabidopsis, Cell Nucleus, Cloning, Molecular, DNA, Antisense, Gene Expression Regulation, Plant, Indoleacetic Acids, Mitosis, Molecular Sequence Data, Plant Roots, Plants, Genetically Modified, Protein Isoforms, Protein Transport, ran GTP-Binding Protein, Sequence Homology, Amino Acid, Signal Transduction, Transformation, Genetic},
	issn = {1040-4651},
	author = {Kim, S H and Arnold, D and Lloyd, A and Roux, S J}
}
@article {2967,
	title = {Signal transduction mechanisms in plants: an overview.},
	journal = {Curr Sci},
	volume = {80},
	number = {2},
	year = {2001},
	month = {2001 Jan 25},
	pages = {170-7},
	abstract = {This article provides an overview on recent advances in some of the basic signalling mechanisms that participate in a wide variety of stimulus-response pathways. The mechanisms include calcium-based signalling, G-protein-mediated-signalling and signalling involving inositol phospholipids, with discussion on the role of protein kinases and phosphatases interspersed. As a further defining feature, the article highlights recent exciting findings on three extracellular components that have not been given coverage in previous reviews of signal transduction in plants, extracellular calmodulin, extracellular ATP, and integrin-like receptors, all of which affect plant growth and development.},
	keywords = {Adenosine Triphosphate, Annexins, Calcium, Calmodulin, GTP-Binding Proteins, Integrins, Plant Physiological Phenomena, Plant Proteins, Protein Kinase C, Signal Transduction, Type C Phospholipases},
	issn = {0011-3891},
	author = {Clark, G B and Thompson, G and Roux, S J}
}
@article {2979,
	title = {Gravity-directed calcium current in germinating spores of Ceratopteris richardii.},
	journal = {Planta},
	volume = {210},
	number = {4},
	year = {2000},
	month = {2000 Mar},
	pages = {607-10},
	abstract = {Gravity directs the early polar development in single cells of Ceratopteris richardii Brogn. It acts over a limited period of time during which it irreversibly determines the axis of the spore cell{\textquoteright}s development. A self-referencing calcium selective electrode was utilized to record the net movement of calcium across the cell membrane at different positions around the periphery of the spore during the period in which gravity orients the polarity of the spore. A movement of calcium into the cell along the bottom and out of the cell along the top was detected. This movement was specific, polarized, and strongest in a direction that opposed the vector of gravity. Treatment with nifedipine, a calcium-channel blocker, diminished the calcium current and caused the cell to lose its responsiveness to the orienting influence of gravity. Results shown suggest that calcium plays a crucial role in the ability of a single cell to respond to gravity and in the subsequent establishment of its polarity.},
	keywords = {Calcium, Calcium Channel Blockers, Calcium Channels, Cell Nucleus, Cell Polarity, Germination, Gravitropism, Light, Nifedipine, Plant Development, Plants, Spores},
	issn = {0032-0935},
	author = {Chatterjee, A and Porterfield, D M and Smith, P S and Roux, S J}
}
@article {2980,
	title = {A role for ectophosphatase in xenobiotic resistance.},
	journal = {Plant Cell},
	volume = {12},
	number = {4},
	year = {2000},
	month = {2000 Apr},
	pages = {519-33},
	abstract = {Xenobiotic resistance in animals, plants, yeast, and bacteria is known to involve ATP binding cassette transporters that efflux invading toxins. We present data from yeast and a higher plant indicating that xenobiotic resistance also involves extracellular ATP degradation. Transgenic upregulation of ecto-ATPase alone confers resistance to organisms that have had no previous exposure to toxins. Similarly, cells that are deficient in extracellular ATPase activity are more sensitive to xenobiotics. On the basis of these and other supporting data, we hypothesize that the hydrolysis of extracellular ATP by phosphatases and ATPases may be necessary for the resistance conferred by P-glycoprotein.},
	keywords = {Adenosine, Adenosine Triphosphatases, Adenosine Triphosphate, Apyrase, Arabidopsis, ATP-Binding Cassette Transporters, Cycloheximide, Drug Resistance, Microbial, Drug Resistance, Multiple, Enzyme Induction, Genes, Fungal, Genes, Plant, Membrane Proteins, Models, Biological, Mutation, Nigericin, P-Glycoprotein, Phosphoric Monoester Hydrolases, Plant Leaves, Plant Proteins, Plants, Genetically Modified, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Xenobiotics},
	issn = {1040-4651},
	author = {Thomas, C and Rajagopal, A and Windsor, B and Dudler, R and Lloyd, A and Roux, S J}
}
@article {2969,
	title = {Ceratopteris richardii: a productive model for revealing secrets of signaling and development.},
	journal = {J Plant Growth Regul},
	volume = {19},
	number = {3},
	year = {2000},
	month = {2000 Sep},
	pages = {284-9},
	abstract = {Ceratopteris richardii is an aquatic fern grown in tropical and subtropical regions of the world. It is proven to be a productive model system for studies in the genetics, biochemistry, and cell biology of basic biologic processes that occur in early gametophytic development. It provides several advantages to biologists, especially those interested in gravitational biology, polarity development, and in the genetics of sexual development. It is easy to culture, has a relatively short life cycle, and offers an array of attractive features that facilitate genetic studies. The germination and early development of large populations of genetically identical spores are easy to synchronize, and both the direction of polarity development and cell-level gravity responses can be measured and readily manipulated within the first 24 h of spore development. Although there is no reliable transformation system available yet in Ceratopteris, recent studies suggest that the technique of RNA interference can be used to block translation of specific genes in a related fern, Marsilea, and current studies will soon reveal the applicability of this approach, as well as of other transformation approaches, in Ceratopteris. A recently completed expressed sequence tag (EST) sequencing project makes available the partial sequence of more than 2000 cDNAs, representing a significant percentage of the genes being expressed during the first 24 h of spore germination, when many developmentally interesting processes are occurring. A microarray of these ESTs is being constructed, so especially for those scientists interested in basic cellular phenomena that occur early in spore germination, the availability of the ESTs and of the microarray will make Ceratopteris an even more attractive model system.},
	keywords = {Base Sequence, Cell Physiological Phenomena, Cell Polarity, Ferns, Germination, Gravitation, Models, Biological, Plant Physiological Phenomena, RNA, Plant, Signal Transduction, Spores},
	issn = {0721-7595},
	author = {Chatterjee, A and Roux, S J}
}
@article {2970,
	title = {Redistribution of annexin in gravistimulated pea plumules.},
	journal = {Plant Physiol Biochem},
	volume = {38},
	number = {12},
	year = {2000},
	month = {2000 Dec},
	pages = {937-47},
	abstract = {We used immunocytochemistry to investigate the effects of gravistimulation on annexin localization in etiolated pea plumule shoots. In longitudinal sections, an asymmetric annexin immunostaining pattern was observed in a defined group of cells located just basipetal to apical meristems at the main shoot apex and at all of the axillary buds, an area classically referred to as the leaf gap. The pattern was observed using both protein-A-purified anti-annexin and affinity-purified anti-annexin antibodies for the immunostaining. A subset of the cells with the annexin staining also showed an unusually high level of periodic acid Schiff (PAS) staining in their cell walls. Prior to gravistimulation, the highest concentration of annexin was oriented toward the direction of gravity along the apical end of these immunostained cells. In contrast, both at 15 and 30 min after gravistimulation, the annexin immunostain became more evenly distributed all around the cell and more distinctly cell peripheral. The asymmetry along the lower wall of these cells was no longer evident. In accord with current models of annexin action, we interpret the results to indicate that annexin-mediated secretion in the leaf gap area is preferentially toward the apical meristem prior to gravistimulation, and that gravistimulation results in a redirection of this secretion. These data are to our knowledge the first to show a correlation between the vector of gravity and the distribution of annexins in the cells of flowering plants.},
	keywords = {Annexins, Cell Wall, Cytoplasm, Gravitation, Gravitropism, Immunohistochemistry, Microscopy, Fluorescence, Peas, Periodic Acid-Schiff Reaction, Plant Proteins, Plant Shoots, Plastids},
	issn = {0981-9428},
	author = {Clark, G B and Rafati, D S and Bolton, R J and Dauwalder, M and Roux, S J}
}
@article {2977,
	title = {Regulation of a recombinant pea nuclear apyrase by calmodulin and casein kinase II.},
	journal = {Biochim Biophys Acta},
	volume = {1494},
	number = {3},
	year = {2000},
	month = {2000 Dec 1},
	pages = {248-55},
	abstract = {A cDNA encoding a pea nuclear apyrase was previously cloned. Overexpressions of a full-length and a truncated cDNA have been successfully expressed in Escherichia coli BL21(DE3). The resulting fusion proteins, apyrase and the C-terminus (residues 315-453) of apyrase, were used for calmodulin (CaM) binding and phosphorylation studies. Fusion protein apyrase but not the C-terminus of apyrase can be recognized by polyclonal antibody pc480. This suggested that the motif recognized by pc480 was located in the N-terminal region of apyrase. The recombinant apyrase protein also showed an activity 70 times higher than that of endogenous apyrase using ATP as a substrate. The recombinant apyrase has a preference for ATP more than other nucleoside triphosphate substrates. CaM can bind to recombinant apyrase, but not to the C-terminus of apyrase. This implies that the CaM-binding domain must be in the first 315 amino acids of the N-terminal region of apyrase. We found that one segment from residue 293 to 308 was a good candidate for the CaM-binding domain. This segment 293 FNKCKNTIRKALKLNY 308 has a basic amphiphilic-helical structure, which shows the predominance of basic residues on one side and hydrophobic residues on the other when displayed on a helical wheel plot. Using the gel mobility shift binding assay, this synthetic peptide was shown to bind to CaM, indicating that it is the CaM-binding domain. Both recombinant apyrase and the C-terminus of apyrase can be phosphorylated by a recombinant human protein kinase CKII. Phosphorylation does not affect CaM binding to recombinant apyrase. However, CaM does inhibit CKII phosphorylation of recombinant apyrase and this inhibition can be blocked by 5 mM EGTA.},
	keywords = {Amino Acid Sequence, Apyrase, Binding Sites, Calmodulin, Casein Kinase II, Cell Nucleus, Cloning, Molecular, DNA, Complementary, Escherichia coli, Gene Expression Regulation, Enzymologic, Models, Molecular, Molecular Sequence Data, Molecular Weight, Peas, Phosphorylation, Protein-Serine-Threonine Kinases, Recombinant Fusion Proteins},
	issn = {0006-3002},
	author = {Hsieh, H L and Song, C J and Roux, S J}
}
@article {2978,
	title = {Technical advance: identification of plant actin-binding proteins by F-actin affinity chromatography.},
	journal = {Plant J},
	volume = {24},
	number = {1},
	year = {2000},
	month = {2000 Oct},
	pages = {127-37},
	abstract = {Proteins that interact with the actin cytoskeleton often modulate the dynamics or organization of the cytoskeleton or use the cytoskeleton to control their localization. In plants, very few actin-binding proteins have been identified and most are thought to modulate cytoskeleton function. To identify actin-binding proteins that are unique to plants, the development of new biochemical procedures will be critical. Affinity columns using actin monomers (globular actin, G-actin) or actin filaments (filamentous actin, F-actin) have been used to identify actin-binding proteins from a wide variety of organisms. Monomeric actin from zucchini (Cucurbita pepo L.) hypocotyl tissue was purified to electrophoretic homogeneity and shown to be native and competent for polymerization to actin filaments. G-actin, F-actin and bovine serum albumin affinity columns were prepared and used to separate samples enriched in either soluble or membrane-associated actin-binding proteins. Extracts of soluble actin-binding proteins yield distinct patterns when eluted from the G-actin and F-actin columns, respectively, leading to the identification of a putative F-actin-binding protein of approximately 40 kDa. When plasma membrane-associated proteins were applied to these columns, two abundant polypeptides eluted selectively from the F-actin column and cross-reacted with antiserum against pea annexins. Additionally, a protein that binds auxin transport inhibitors, the naphthylphthalamic acid binding protein, which has been previously suggested to associate with the actin cytoskeleton, was eluted in a single peak from the F-actin column. These experiments provide a new approach that may help to identify novel actin-binding proteins from plants.},
	keywords = {Actins, Cell Membrane, Chromatography, Affinity, Contractile Proteins, Electrophoresis, Polyacrylamide Gel, Hypocotyl, Immunoblotting, Microfilament Proteins, Plant Proteins, Profilins, Vegetables, Zea mays},
	issn = {0960-7412},
	author = {Hu, S and Brady, S R and Kovar, D R and Staiger, C J and Clark, G B and Roux, S J and Muday, G K}
}
@article {2981,
	title = {Antisense expression of the CK2 alpha-subunit gene in Arabidopsis. Effects on light-regulated gene expression and plant growth.},
	journal = {Plant Physiol},
	volume = {119},
	number = {3},
	year = {1999},
	month = {1999 Mar},
	pages = {989-1000},
	abstract = {The protein kinase CK2 (formerly casein kinase II) is thought to be involved in light-regulated gene expression in plants because of its ability to phosphorylate transcription factors that bind to the promoter regions of light-regulated genes in vitro. To address this possibility in vivo and to learn more about the potential physiological roles of CK2 in plants, we transformed Arabidopsis with an antisense construct of the CK2 alpha-subunit gene and investigated both morphological and molecular phenotypes. Antisense transformants had a smaller adult leaf size and showed increased expression of chs in darkness and of cab and rbcS after red-light treatment. The latter molecular phenotype implied that CK2 might serve as one of several negative and quantitative effectors in light-regulated gene expression. The possible mechanism of CK2 action and its involvement in the phytochrome signal transduction pathway are discussed.},
	keywords = {Arabidopsis, Base Sequence, Casein Kinase II, CDC2 Protein Kinase, DNA, Antisense, Gene Expression Regulation, Enzymologic, Gene Expression Regulation, Plant, Genes, Plant, Light, Plant Leaves, Plants, Genetically Modified, Protein-Serine-Threonine Kinases, RNA, Messenger, RNA, Plant, Transformation, Genetic},
	issn = {0032-0889},
	author = {Lee, Y and Lloyd, A M and Roux, S J}
}
@article {2971,
	title = {A novel beta-glucosidase from the cell wall of maize (Zea mays L.): rapid purification and partial characterization.},
	journal = {J Plant Physiol},
	volume = {155},
	number = {4-5},
	year = {1999},
	month = {1999 Oct},
	pages = {462-9},
	abstract = {Plants have a variety of glycosidic conjugates of hormones, defense compounds, and other molecules that are hydrolyzed by beta-glucosidases (beta-D-glucoside glucohydrolases, E.C. 3.2.1.21). Workers have reported several beta-glucosidases from maize (Zea mays L.; Poaceae), but have localized them mostly by indirect means. We have purified and partly characterized a 58-Ku beta-glucosidase from maize, which we conclude from a partial sequence analysis, from kinetic data, and from its localization is not identical to any of those already reported. A monoclonal antibody, mWP 19, binds this enzyme, and localizes it in the cell walls of maize coleoptiles. An earlier report showed that mWP19 inhibits peroxidase activity in crude cell wall extracts and can immunoprecipitate peroxidase activity from these extracts, yet purified preparations of the 58 Ku protein had little or no peroxidase activity. The level of sequence similarity between beta-glucosidases and peroxidases makes it unlikely that these enzymes share epitopes in common. Contrary to a previous conclusion, these results suggest that the enzyme recognized by mWP19 is not a peroxidase, but there is a wall peroxidase closely associated with the 58 Ku beta-glucosidase in crude preparations. Other workers also have co-purified distinct proteins with beta-glucosidases. We found no significant charge in the level of immunodetectable beta-glucosidase in mesocotyls or coleoptiles that precedes the red light-induced changes in the growth rate of these tissues.},
	keywords = {Antibodies, Monoclonal, beta-Glucosidase, Cell Wall, Cotyledon, Electrophoresis, Polyacrylamide Gel, Hydrogen-Ion Concentration, Isoenzymes, Light, Molecular Sequence Data, Peroxidases, Plant Proteins, Sequence Analysis, Protein, Zea mays},
	issn = {0176-1617},
	author = {Nematollahi, W P and Roux, S J}
}
@article {2982,
	title = {Influence of gravity and light on the developmental polarity of Ceratopteris richardii fern spores.},
	journal = {Planta},
	volume = {205},
	number = {4},
	year = {1998},
	month = {1998 Aug},
	pages = {553-60},
	abstract = {The polarity of germinating single-celled spores of the fern Ceratopteris richardii Brogn. is influenced by gravity during a time period prior to the first cellular division designated a "polarity-determination window". After this window closes, control of polarity is seen in the downward (with respect to gravity) migration of the nucleus along the proximal face of the spore and the subsequent downward growth of the primary rhizoid. When spores are germinated on a clinostat the direction of nuclear migration and subsequent primary rhizoid growth is random. However, in each case the direction of nuclear migration predicts the direction of rhizoid elongation. Although it is the most obvious movement, the downward migration is not the first movement of the nucleus. During the polarity-determination window, the nucleus moves randomly within a region centered behind the trilete marking. While the polarity of many fern spores has been reported to be controlled by light, spores of C. richardii are the first documented to have their polarity influenced by gravity. Directional white light also affects the polarity of these spores, but this influence is slight and is secondary to that of gravity.},
	keywords = {Cell Nucleus, Cell Polarity, Germination, Gravitation, Light, Plant Physiological Phenomena, Spores},
	issn = {0032-0935},
	author = {Edwards, E S and Roux, S J}
}
@article {2973,
	title = {Gravity and light control of the developmental polarity of regenerating protoplasts isolated from prothallial cells of the fern Ceratopteris richardii.},
	journal = {Plant Cell Rep},
	volume = {17},
	number = {9},
	year = {1998},
	month = {1998 Jun},
	pages = {711-6},
	abstract = {A procedure has been developed for isolating protoplasts from prothalli of Ceratopteris richardii which can be cultured and are capable of regeneration. Protoplasts were isolated from 2-week-old gametophytes in a medium containing wall-digesting enzymes in 0.5 M sucrose, followed by purification of the released protoplasts by floating them up into a 0.5 M sorbitol layer. Regeneration occurred over a period of 10-24 days, and, under optimal osmotic conditions, followed the developmental pattern seen during spore germination, in that the first division gave rise to a primary rhizoid. Thus, prothallial protoplasts are comparable to germinating spores as suitable models for studies of developmental polarity in single cells. As in germinating spores, the polarity of development in regenerating protoplasts is influenced by the vectors of gravity and unilateral light. However, the relative influence of light in fixing this polarity is greater in regenerating protoplasts, while in germinating spores, the influence of gravity is greater.},
	keywords = {Cell Polarity, Gravitation, Gravitropism, Light, Osmotic Pressure, Plant Cells, Plant Development, Plant Physiological Phenomena, Plants, Protoplasts, Spores},
	issn = {0721-7714},
	author = {Edwards, E S and Roux, S J}
}
@article {2972,
	title = {Immunological and biochemical evidence for nuclear localization of annexin in peas.},
	journal = {Plant Physiol Biochem},
	volume = {36},
	number = {9},
	year = {1998},
	month = {1998 Sep},
	pages = {621-7},
	abstract = {Immunofluorescent localization of annexins using an anti-pea annexin polyclonal antibody (anti-p35) in pea (Pisum sativum) leaf and stem epidermal peels showed staining of the nuclei and the cell periphery. Nuclear staining was also seen in cell teases prepared from pea plumules. The amount of nuclear stain was reduced both by fixation time and by dehydration and organic solvent treatment. Observation with confocal microscopy demonstrated that the anti-p35 stain was diffusely distributed throughout the nuclear structure. Immunoblots of purified nuclei, nuclear envelope matrix, nucleolar, and chromatin fractions showed a cross-reactive protein band of 35 kDa. These data are the first to show annexins localized in plant cell nuclei where they may play a role in nuclear function.},
	keywords = {Annexins, Blotting, Western, Cell Nucleus, Immunohistochemistry, Microscopy, Confocal, Microscopy, Fluorescence, Peas, Plant Epidermis, Plant Leaves, Plant Proteins, Tissue Fixation},
	issn = {0981-9428},
	author = {Clark, G B and Dauwalder, M and Roux, S J}
}
@article {2984,
	title = {The influence of gravity and light on developmental polarity of single cells of Ceratopteris richardii gametophytes.},
	journal = {Biol Bull},
	volume = {192},
	number = {1},
	year = {1997},
	month = {1997 Feb},
	pages = {139-40},
	keywords = {Cell Nucleus, Cell Polarity, Germination, Gravitation, Gravitropism, Gravity Sensing, Light, Plant Cells, Plant Development, Plant Physiological Phenomena, Plants, Spores},
	issn = {0006-3185},
	author = {Edwards, E S and Roux, S J}
}
@article {2983,
	title = {Light regulation of the abundance of mRNA encoding a nucleolin-like protein localized in the nucleoli of pea nuclei.},
	journal = {Plant Physiol},
	volume = {114},
	number = {2},
	year = {1997},
	month = {1997 Jun},
	pages = {643-52},
	abstract = {A cDNA encoding a nucleolar protein was selected from a pea (Pisum sativum) plumule library, cloned, and sequenced. The translated sequence of the cDNA has significant percent identity to Xenopus laevis nucleolin (31\%), the alfalfa (Medicago sativa) nucleolin homolog (66\%), and the yeast (Saccharomyces cerevisiae) nucleolin homolog (NSR1) (28\%). It also has sequence patterns in its primary structure that are characteristic of all nucleolins, including an N-terminal acidic motif, RNA recognition motifs, and a C-terminal Gly- and Arg-rich domain. By immunoblot analysis, the polyclonal antibodies used to select the cDNA bind selectively to a 90-kD protein in purified pea nuclei and nucleoli and to an 88-kD protein in extracts of Escherichia coli expressing the cDNA. In immunolocalization assays of pea plumule cells, the antibodies stained primarily a region surrounding the fibrillar center of nucleoli, where animal nucleolins are typically found. Southern analysis indicated that the pea nucleolin-like protein is encoded by a single gene, and northern analysis showed that the labeled cDNA binds to a single band of RNA, approximately the same size and the cDNA. After irradiation of etiolated pea seedlings by red light, the mRNA level in plumules decreased during the 1st hour and then increased to a peak of six times the 0-h level at 12 h. Far-red light reversed this effect of red light, and the mRNA accumulation from red/far-red light irradiation was equal to that found in the dark control. This indicates that phytochrome may regulate the expression of this gene.},
	keywords = {Amino Acid Sequence, Base Sequence, Cell Nucleolus, Cloning, Molecular, DNA, Complementary, Escherichia coli, Gene Dosage, Gene Expression Regulation, Plant, Immunohistochemistry, Light, Molecular Sequence Data, Nuclear Proteins, Peas, Phosphoproteins, Recombinant Proteins, RNA, Messenger, RNA, Plant, RNA-Binding Proteins, Sequence Analysis, DNA, Sequence Homology, Amino Acid},
	issn = {0032-0889},
	author = {Tong, C G and Reichler, S and Blumenthal, S and Balk, J and Hsieh, H L and Roux, S J}
}
@article {2987,
	title = {Light-modulated abundance of an mRNA encoding a calmodulin-regulated, chromatin-associated NTPase in pea.},
	journal = {Plant Mol Biol},
	volume = {30},
	number = {1},
	year = {1996},
	month = {1996 Jan},
	pages = {135-47},
	abstract = {A CDNA encoding a 47 kDa nucleoside triphosphatase (NTPase) that is associated with the chromatin of pea nuclei has been cloned and sequenced. The translated sequence of the cDNA includes several domains predicted by known biochemical properties of the enzyme, including five motifs characteristic of the ATP-binding domain of many proteins, several potential casein kinase II phosphorylation sites, a helix-turn-helix region characteristic of DNA-binding proteins, and a potential calmodulin-binding domain. The deduced primary structure also includes an N-terminal sequence that is a predicted signal peptide and an internal sequence that could serve as a bipartite-type nuclear localization signal. Both in situ immunocytochemistry of pea plumules and immunoblots of purified cell fractions indicate that most of the immunodetectable NTPase is within the nucleus, a compartment proteins typically reach through nuclear pores rather than through the endoplasmic reticulum pathway. The translated sequence has some similarity to that of human lamin C, but not high enough to account for the earlier observation that IgG against human lamin C binds to the NTPase in immunoblots. Northern blot analysis shows that the NTPase MRNA is strongly expressed in etiolated plumules, but only poorly or not at all in the leaf and stem tissues of light-grown plants. Accumulation of NTPase mRNA in etiolated seedlings is stimulated by brief treatments with both red and far-red light, as is characteristic of very low-fluence phytochrome responses. Southern blotting with pea genomic DNA indicates the NTPase is likely to be encoded by a single gene.},
	keywords = {Acid Anhydride Hydrolases, Amino Acid Sequence, Base Sequence, Calmodulin, Chromatin, Gene Expression Regulation, Plant, Gene Library, Immunoblotting, Light, Molecular Probe Techniques, Molecular Sequence Data, Nucleoside-Triphosphatase, Peas, Protein Conformation, RNA, Messenger, RNA, Plant, Sequence Analysis, DNA, Tissue Distribution},
	issn = {0167-4412},
	author = {Hsieh, H L and Tong, C G and Thomas, C and Roux, S J}
}
@article {2986,
	title = {Partial purification and characterization of a type 1 protein phosphatase in purified nuclei of pea plumules.},
	journal = {Biochem J},
	volume = {319 ( Pt 3)},
	year = {1996},
	month = {1996 Nov 1},
	pages = {985-91},
	abstract = {We report the isolation and characterization of a protein Ser/Thr phosphatase from highly purified pea nuclei. In subnuclear fractions, more than 75\% of Ser/Thr protein phosphatase activity was associated with the chromatin fraction, whereas the other 25\% was in the nuclear membrane/nucleoplasmic fraction when phosphorylase a was used as a substrate. The enzyme was purified approx. 2750-fold to a specific activity of approx. 4000 nmol/min per mg. The molecular mass of the enzyme was 34 kDa as estimated by molecular sieve chromatography, and approx. 40 kDa as estimated by SDS/PAGE. The phosphatase was inhibited by okadaic acid with an IC50 of approx. 15 nM, by rabbit muscle inhibitor 2 with an IC50 of approx. 10 nM, and by microcystin-LR with an IC50 of approx. 0.05 nM. The enzyme did not require Ca2+, Mg2+ or Mn2+ for its activity; instead, these cations showed some inhibitory effects. It was inhibited by NaF or citrate but not by tartrate, molybdate or vanadate under the conditions tested. Its sensitivities towards the various phosphatase inhibitors and its substrate specificity were very similar to those characteristic of the type I Ser/Thr protein phosphatases well studied in animal systems. The enzyme was able to selectively dephosphorylate a 92 kDa nuclear protein that had been phosphorylated by one or more endogenous protein kinases.},
	keywords = {Animals, Cell Nucleus, Chromatin, Chromatography, High Pressure Liquid, Chromatography, Ion Exchange, Isoelectric Focusing, Molecular Weight, Nuclear Proteins, Peas, Phosphoprotein Phosphatases, Phosphoproteins, Rabbits, Substrate Specificity},
	issn = {0264-6021},
	author = {Guo, Y L and Roux, S J}
}
@article {2985,
	title = {Red light-induced appearance of phosphotyrosine-like epitopes on nuclear proteins from pea (Pisum sativum L.) plumules.},
	journal = {Photochem Photobiol},
	volume = {64},
	number = {5},
	year = {1996},
	month = {1996 Nov},
	pages = {863-6},
	abstract = {As assayed by western blot analysis, red light induces the appearance of epitopes recognized by anti-phosphotyrosine antibodies in several pea nuclear proteins. The immunostaining is blocked by preadsorbing the antibodies with phosphotyrosine but not by preadsorbing them with phosphoserine or phosphothreonine. This light response is observed whether the red light irradiation is given to pea plumules or nuclei isolated from the plumules. The red-light-induced response seen in plumules is reversible by a subsequent far-red-light irradiation, indicating that the likely photoreceptor for this response may be phytochrome. By immunoblot analysis pea phytochrome A, but not phytochrome B, can be detected in proteins extracted from pea nuclear chromatin-matrix preparations. Phytochrome A and the protein bands immunostained by anti-phosphotyrosine antibodies can be solubilized from unirradiated pea chromatin by 0.3 M NaCl, but irradiating this preparation with red light does not induce the appearance of phosphotyrosine-like epitopes in any nuclear proteins. These results suggest that the association of phytochrome with purified pea nuclei is such that its conversion to the far-red light-absorbing form can induce a post-translational epitope change in nuclear proteins in vivo.},
	keywords = {Epitopes, Light, Nuclear Proteins, Peas, Phosphotyrosine, Plant Proteins},
	issn = {0031-8655},
	author = {Tong, C G and Kendrick, R E and Roux, S J}
}
@article {2989,
	title = {Assessing potential targets of calcium action in light-modulated gravitropism.},
	journal = {ASGSB Bull},
	volume = {8},
	number = {2},
	year = {1995},
	month = {1995 Oct},
	pages = {83-92},
	abstract = {Light, through the mediation of the pigment phytochrome, modulates the gravitropic response of the shoots and roots of many plants. The transduction of both light and gravity stimuli appears to involve Ca(2+)-regulated steps, one or more of which may represent points of intersection between the two transduction chains. To be confident that Ca2+ plays a critical role in stimulus-response coupling for gravitropism, it will be important to identify specific targets of Ca2+ action whose function can be clearly linked to the regulation of growth. Calcium typically exerts its influence on cell metabolism through binding to and activating key regulatory proteins. The three best characterized of these proteins in plants are the calmodulins, calcium-dependent protein kinases, and annexins. In this review we summarize what is known about the structure and function of these proteins and speculate on how their activation by Ca2+ could influence the differential growth response of gravitropism.},
	keywords = {Amino Acid Sequence, Annexins, Calcium, Calmodulin, Gravitropism, Light, Molecular Sequence Data, Phytochrome, Plant Development, Plant Physiological Phenomena, Plant Proteins, Plant Roots, Plant Shoots, Plants, Protein Kinases},
	issn = {0898-4697},
	author = {Roux, S J}
}
@article {2991,
	title = {Partial purification and characterization of an enzyme from pea nuclei with protein tyrosine phosphatase activity.},
	journal = {Plant Physiol},
	volume = {107},
	number = {1},
	year = {1995},
	month = {1995 Jan},
	pages = {167-75},
	abstract = {A pea (Pisum sativum L.) nuclear enzyme with protein tyrosine phosphatase activity has been partially purified and characterized. The enzyme has a molecular mass of 90 kD as judged by molecular sieve column chromatography and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Like animal protein tyrosine phosphatases it can be inhibited by low concentrations of molybdate and vanadate. It is also inhibited by heparin and spermine but not by either the acid phosphatase inhibitors citrate and tartrate or the protein serine/threonine phosphatase inhibitor okadaic acid. The enzyme does not require Ca2+, Mg2+, or Mn2+ for its activity but is stimulated by ethylenediaminetetraacetate and by ethyleneglycolbis(beta-aminoethyl ether)-N,N{\textquoteright}-tetraacetic acid. It dephosphorylates phosphotyrosine residues on the four different 32P-tyrosine-labeled peptides tested but not the phosphoserine/threonine residues on casein and histone. Like some animal protein tyrosine phosphatases, it has a variable pH optimum depending on the substrate used: the optimum is 5.5 when the substrate is [32P]tyrosine-labeled lysozyme, but it is 7.0 when the substrate is [32P]tyrosine-labeled poly(glutamic acid, tyrosine). It has a Km of 4 microM when the lysozyme protein is used as a substrate.},
	keywords = {Calcium Chloride, Cell Nucleus, Chelating Agents, Chlorides, Citric Acid, Edetic Acid, Egtazic Acid, Enzyme Inhibitors, Heparin, Magnesium Chloride, Manganese Compounds, Molybdenum, Okadaic Acid, Peas, Phosphorylation, Protein Tyrosine Phosphatases, Sodium Fluoride, Spermine, Tartrates, Vanadates, Zinc Compounds},
	issn = {0032-0889},
	author = {Guo, Y L and Roux, S J}
}
@article {2990,
	title = {Polar distribution of annexin-like proteins during phytochrome-mediated initiation and growth of rhizoids in the ferns Dryopteris and Anemia.},
	journal = {Planta},
	volume = {197},
	number = {2},
	year = {1995},
	month = {1995},
	pages = {376-84},
	abstract = {Although the calcium requirement of phytochrome-mediated fern spore germination and early rhizoid growth is well established, the calcium-binding proteins that serve as transducers for these responses are not known. Here we report the presence of annexin-like proteins in germinating spores of Dryopteris filix-mas (L.) Schott and Anemia phyllitidis (L.) Sw. and evidence that they may be important participants in early photomorphogenic changes in gametophytes. Immunolocalization and immunoblot assays of these proteins were carried out using polyclonal antibodies raised either against a 35-kDa annexin-like protein from pea or against anchorin CII from chicken. Western-blot analysis showed that crude protein extracts obtained from both species after red-light treatment contained two cross-reactive protein bands with molecular weights around 70 kDa. These proteins were annexin-like in that they bound to a phosphatidylserine affinity column in a calcium-dependent fashion. Using this column, two protein bands around 70 kDa, i.e. 67 and 73 kDa, were partially purified together with proteins at 36 kDa and a doublet at 54 kDa. Proteins of these latter molecular weights are suggested to be members of the annexin family, but no cross-reactivity could be found between these and the two antibodies used in our investigations. Immunodetectable levels of these proteins were observed only after light-mediated induction of spore germination. Imaging of the immuno-localization patterns observed with both antibodies showed that the annexin-like proteins are concentrated at the extreme tips of the rhizoids in D. filix-mas and A. phyllitidis during rhizoid initiation and all stages of elongation. We suggest that these proteins may play a major role in the tip-oriented exocytosis events that are critical for the initiation and growth of fern rhizoids.},
	keywords = {Annexins, Calcium-Binding Proteins, Culture Media, Germination, Immunohistochemistry, Phytochrome, Plant Development, Plant Physiological Phenomena, Plant Proteins, Plant Roots, Plants, Spores},
	issn = {0032-0935},
	author = {Clark, G B and Turnwald, S and Tirlapur, U K and Haas, C J and von der Mark, K and Roux, S J and Scheuerlein, R}
}
@article {2988,
	title = {Annexins of plant cells.},
	journal = {Plant Physiol},
	volume = {109},
	number = {4},
	year = {1995},
	month = {1995 Dec},
	pages = {1133-9},
	keywords = {Amino Acid Sequence, Animals, Annexins, Consensus Sequence, Drosophila, Molecular Sequence Data, Plant Physiological Phenomena, Repetitive Sequences, Nucleic Acid, Sequence Homology, Amino Acid, Signal Transduction},
	issn = {0032-0889},
	author = {Clark, G B and Roux, S J}
}
@article {2993,
	title = {Immunolocalization of an annexin-like protein in corn.},
	journal = {Adv Space Res},
	volume = {14},
	number = {8},
	year = {1994},
	month = {1994},
	pages = {341-6},
	abstract = {Although calcium has been proposed to be an important regulatory element in plant gravitropic growth, as yet no specific function of Ca2+ in growth regulation has been discovered. Our recent studies on a Ca(2+)-binding protein in pea seedlings called p35 indicate that it is a member of the annexin family of proteins and may play a key role in growth regulation through its function in delivering polysaccharides needed for wall construction. We previously reported the isolation of p35 from pea plumules and the production of polyclonal antibodies to it. Immunolocalizaton analyses of p35 in pea tissues revealed high levels of staining in secretory cell types such as developing vascular cells and outer root cap cells. To test how general was the occurrence and distribution of this annexin-like protein in plant cells we initiated an analysis of annexins in the monocot corn using immunological techniques. Our results indicate the immunochemical properties and localization of corn annexins are very similar to those reported for pea. They are consistent with the postulate that annexins may play a general role in the regulation of the secretion of wall polysaccharides needed for growth, and thus could be an important target of calcium action during gravitropic growth.},
	keywords = {Annexins, Blotting, Western, Calcium, Cell Wall, Gravitropism, Immunohistochemistry, Plant Proteins, Plant Roots, Polysaccharides, Precipitin Tests, Signal Transduction, Zea mays},
	issn = {0273-1177},
	author = {Clark, G B and Dauwalder, M and Roux, S J}
}
@article {2992,
	title = {Limited period of graviresponsiveness in germinating spores of Ceratopteris richardii.},
	journal = {Planta},
	volume = {195},
	year = {1994},
	month = {1994},
	pages = {150-2},
	abstract = {Rhizoids of the fern Ceratopteris richardii Brogn. usually emerge 40 h after germination is initiated by light, and more than 90\% of them emerge growing in a downward direction. However, when the spores are germinated on a clinostat, the emerging rhizoids show no preferential orientation. This indicates that under normal 1 g conditions the initial growth direction of rhizoids can be oriented by gravity. If the orientation of the spores is changed 3 h or less after the start of germination, the growth direction of most emerging rhizoids becomes downward relative to the new orientation. However, if the orientation of the spores is changed by 180 degrees 8 h or more after germination is initiated by light, most rhizoids emerge growing upward; i.e., the same direction as if there had been no orientation change. Emerged rhizoids also do not change their direction of growth if their orientation is changed. These results indicate that the growth direction of emerging rhizoids is set by gravity prior to actual emergence, and that the time of full orientation responsiveness is limited to a period ranging from the initiation of germination to about 3-4 h after the start of germination. There is a gravity-oriented nuclear movement beginning at about 13 h after germination, and this movement appears to predict the initial growth direction of rhizoids.},
	keywords = {Cell Nucleus, Cell Polarity, Germination, Gravitation, Gravitropism, Light, Plant Cells, Plant Development, Plant Roots, Plants, Rotation, Spores, Time Factors},
	issn = {0032-0935},
	author = {Edwards, E S and Roux, S J}
}
@article {2994,
	title = {Casein Kinase II-Type Protein Kinase from Pea Cytoplasm and Its Inactivation by Alkaline Phosphatase in Vitro.},
	journal = {Plant Physiol},
	volume = {103},
	number = {3},
	year = {1993},
	month = {1993 Nov},
	pages = {955-962},
	abstract = {A casein kinase II-type protein kinase has been purified from the cytosolic fraction of etiolated pea (Pisum sativum L.) plumules to about 90\% purity as judged from Coomassie blue stained sodium dodecyl sulfate-polyacrylamide gels. This kinase has a tetrameric [alpha][alpha]{\textquoteright}[beta]2 structure with a native molecular mass of 150 kD, and subunit molecular masses of 41 and 40 kD for the two catalytic subunits ([alpha] and [alpha]{\textquoteright}) and 35 kD for the putative regulatory subunit ([beta]).Casein and phosvitin can be used as artificial substrates for this kinase. Both serine and threonine residues were phosphorylated when mixed casein, [beta]-casein, or phosvitin were used as the substrate, whereas only serine was phosphorylated if [alpha]-casein or histone III-S was the substrate. The kinase activity was stimulated 130\% by 0.5 mM spermine (the concentration required for 50\% of maximal enzyme activity [A50] = 0.1 mM) and 80\% by 2.5 mM spermidine (A50 = 0.4 mM), whereas putrescine and cadaverine had no effect. The kinase was very sensitive to inhibition by heparin (concentration for 50\% inhibition [I50] = 0.025 [mu]g/mL). In contrast to most other casein kinase II-type protein kinases, this preparation was inhibited by K+ and Na+, with I50 values of 75 and 65 mM, respectively. Pretreatment of the purified kinase preparation in vitro with alkaline phosphatase caused a 5-fold decrease in its activity. Additionally, this kinase also lost its activity when its [beta] subunit was autophosphorylated in the absence of substrate. These results suggest that the activity of this casein kinase II protein kinase may be regulated by the phosphorylation state of two different sites in its multimeric structure.},
	issn = {1532-2548},
	author = {Zhang, S. and Jin, C. D. and Roux, S J}
}
@article {2995,
	title = {The major nucleoside triphosphatase in pea (Pisum sativum L.) nuclei and in rat liver nuclei share common epitopes also present in nuclear lamins.},
	journal = {Plant Physiol},
	volume = {101},
	number = {3},
	year = {1993},
	month = {1993 Mar},
	pages = {1005-11},
	abstract = {The major nucleoside triphosphatase (NTPase) activities in mammalian and pea (Pisum sativum L.) nuclei are associated with enzymes that are very similar both biochemically and immunochemically. The major NTPase from rat liver nuclei appears to be a 46-kD enzyme that represents the N-terminal portion of lamins A and C, two lamina proteins that apparently arise from the same gene by alternate splicing. Monoclonal antibody (MAb) G2, raised to human lamin C, both immunoprecipitates the major (47 kD) NTPase in pea nuclei and recognizes it in western blot analyses. A polyclonal antibody preparation raised to the 47-kD pea NTPase (pc480) reacts with the same lamin bands that are recognized by MAb G2 in mammalian nuclei. The pc480 antibodies also bind to the same lamin-like bands in pea nuclear envelope-matrix preparations that are recognized by G2 and three other MAbs known to bind to mammalian lamins. In immunofluorescence assays, pc480 and anti-lamin antibodies stain both cytoplasmic and nuclear antigens in plant cells, with slightly enhanced staining along the periphery of the nuclei. These results indicate that the pea and rat liver NTPases are structurally similar and that, in pea nuclei as in rat liver nuclei, the major NTPase is probably derived from a lamin precursor by proteolysis.},
	keywords = {Acid Anhydride Hydrolases, Adenosine Triphosphate, Animals, Blotting, Western, Cell Nucleus, Epitopes, Fabaceae, Fluorescent Antibody Technique, Humans, Lamin Type A, Lamins, Liver, Mammals, Nuclear Proteins, Nucleoside-Triphosphatase, Plants, Medicinal, Rats},
	issn = {0032-0889},
	author = {Tong, C G and Dauwalder, M and Clawson, G A and Hatem, C L and Roux, S J}
}
@article {2996,
	title = {Phytochrome regulates GTP-binding protein activity in the envelope of pea nuclei.},
	journal = {Plant J},
	volume = {4},
	number = {2},
	year = {1993},
	month = {1993},
	pages = {399-402},
	abstract = {Three GTP-binding proteins with apparent molecular masses of 27, 28 and 30 kDa have been detected in isolated nuclei of etiolated pea plumules. After LDS-PAGE and transfer to nitrocellulose these proteins bind [32P]GTP in the presence of excess ATP, suggesting that they are monomeric G proteins. When nuclei are disrupted, three proteins co-purify with the nuclear envelope fraction and are highly enriched in this fraction. The level of [32P]GTP-binding for all three protein bands is significantly increased when harvested pea plumules are irradiated by red light, and this effect is reversed by far-red light. The results indicate that GTP-binding activity associated with the nuclear envelope of plant cells is photoreversibly regulated by the pigment phytochrome.},
	keywords = {Cell Nucleus, GTP-Binding Proteins, Light, Peas, Phosphorus Radioisotopes, Phytochrome, Signal Transduction},
	issn = {0960-7412},
	author = {Clark, G B and Memon, A R and Memon, A R and Thompson, G A and Roux, S J}
}
@article {3000,
	title = {Purification and characterization of a casein kinase 2-type protein kinase from pea nuclei.},
	journal = {Plant Physiol},
	volume = {99},
	number = {2},
	year = {1992},
	month = {1992 Jun},
	pages = {686-92},
	abstract = {Almost all the polyamine-stimulated protein kinase activity associated with the chromatin fraction of nuclei purified from etiolated pea (Pisum sativum L.) plumules is present in a single enzyme that can be extracted from chromatin by 0.35 molar NaCl. This protein kinase can be further purified over 2000-fold by salt fractionation and anion-exchange and casein-agarose column chromatography, after which it is more than 90\% pure. The purified kinase has a specific activity of about 650 nanomoles per minute per milligram protein in the absence of polyamines, with either ATP or GTP as phosphoryl donor. Spermidine can stimulate its activity fourfold, with half-maximal activation at about 2 millimolar. Spermine and putrescine also stimulate activity, although somewhat less effectively. This kinase has a tetrameric alpha 2 beta 2 structure with a native molecular weight of 130,000, and subunit molecular weights of 36,000 for the catalytic subunit (alpha) and 29,000 for the regulatory subunit (beta). In western blot analyses, only the alpha subunit reacts strongly with polyclonal antibodies to a Drosophila casein kinase II. The pea kinase can use casein and phosvitin as artificial substrates, phosphorylating both the serine and threonine residues of casein. It has a pH optimum near 8.0, a Vmax of 1.5 micromoles per minute per milligram protein, and a Km for ATP of approximately 75 micromolar. Its activity can be almost completely inhibited by heparin at 5 micrograms per milliliter, but is relatively insensitive to concentrations of staurosporine, K252a, and chlorpromazine that strongly antagonize Ca(2+) -regulated protein kinases. These results are discussed in relation to recent findings that casein kinase 2-type kinases may phosphorylate trans-acting factors that bind to light-regulated promoters in plants.},
	keywords = {Casein Kinase II, Caseins, Cell Nucleus, DNA, Plant, DNA-Binding Proteins, Peas, Phosphorylation, Phosvitin, Plant Proteins, Polyamines, Protein Kinases, Protein-Serine-Threonine Kinases, Substrate Specificity},
	issn = {0032-0889},
	author = {Li, H and Roux, S J}
}
@article {3002,
	title = {Purification and immunolocalization of an annexin-like protein in pea seedlings.},
	journal = {Planta},
	volume = {187},
	year = {1992},
	month = {1992},
	pages = {1-9},
	abstract = {As part of a study to identify potential targets of calcium action in plant cells, a 35-kDa, annexin-like protein was purified from pea (Pisum sativum L.) plumules by a method used to purify animal annexins. This protein, called p35, binds to a phosphatidylserine affinity column in a calcium-dependent manner and binds 45Ca2+ in a dot-blot assay. Preliminary sequence data confirm a relationship for p35 with the annexin family of proteins. Polyclonal antibodies have been raised which recognize p35 in Western and dot blots. Immunofluorescence and immunogold techniques were used to study the distribution and subcellular localization of p35 in pea plumules and roots. The highest levels of immunostain were found in young developing vascular cells producing wall thickenings and in peripheral root-cap cells releasing slime. This localization in cells which are actively involved in secretion is of interest because one function suggested for the animal annexins is involvement in the mediation of exocytosis.},
	keywords = {Amino Acid Sequence, Annexins, Calcium, Cell Membrane, Exocytosis, Golgi Apparatus, Immunohistochemistry, Microscopy, Electron, Molecular Sequence Data, Molecular Weight, Peas, Plant Proteins, Plant Root Cap},
	issn = {0032-0935},
	author = {Clark, G B and Dauwalder, M and Roux, S J}
}
@article {3001,
	title = {Purification and immunolocalization of an annexin-like protein in pea seedlings.},
	journal = {Planta},
	volume = {187},
	number = {1},
	year = {1992},
	month = {1992 Apr},
	pages = {1-9},
	abstract = {As part of a study to identify potential targets of calcium action in plant cells, a 35-kDa, annexin-like protein was purified from pea (Pisum sativum L.) plumules by a method used to purify animal annexins. This protein, called p35, binds to a phosphatidylserine affinity column in a calcium-dependent manner and binds (45)Ca(2+) in a dot-blot assay. Preliminary sequence data confirm a relationship for p35 with the annexin family of proteins. Polyclonal antibodies have been raised which recognize p35 in Western and dot blots. Immunofluorescence and immunogold techniques were used to study the distribution and subcellular localization of p35 in pea plumules and roots. The highest levels of immunostain were found in young developing vascular cells producing wall thickenings and in peripheral root-cap cells releasing slime. This localization in cells which are actively involved in secretion is of interest because one function suggested for the animal annexins is involvement in the mediation of exocytosis.},
	issn = {0032-0935},
	doi = {10.1007/BF00201617},
	author = {Clark, G B and Dauwalder, M and Roux, S J}
}
@article {2999,
	title = {What remains of the Cholodny-Went theory? Riding the transduction train to the answer.},
	journal = {Plant Cell Environ},
	volume = {15},
	number = {7},
	year = {1992},
	month = {1992 Sep},
	pages = {783-4},
	keywords = {Calcium, Gravitation, GTP-Binding Proteins, Indoleacetic Acids, Light, Plant Development, Plant Physiological Phenomena, Plants, Signal Transduction, Tropism},
	issn = {0140-7791},
	author = {Roux, S J}
}
@article {2997,
	title = {Calcium-regulated nuclear enzymes: potential mediators of phytochrome-induced changes in nuclear metabolism?},
	journal = {Photochem Photobiol},
	volume = {56},
	number = {5},
	year = {1992},
	month = {1992 Nov},
	pages = {811-4},
	abstract = {Calcium ions have been proposed to serve as important regulatory elements in stimulus-response coupling for phytochrome responses. An important test of this hypothesis will be to identify specific targets of calcium action that are required for some growth or development process induced by the photoactivated form of phytochrome (Pfr). Initial studies have revealed that there are at least two enzymes in pea nuclei that are stimulated by Pfr in a Ca(2+)-dependent fashion, a calmodulin-regulated nucleoside triphosphatase and a calmodulin-independent but Ca(2+)-dependent protein kinase. The nucleoside triphosphatase appears to be associated with the nuclear envelope, while the protein kinase co-purifies with a nuclear fraction highly enriched for chromatin. This short review summarizes the latest findings on these enzymes and relates them to what is known about Pfr-regulated nuclear metabolism.},
	keywords = {Calcium, Cell Nucleus, Photochemistry, Phytochrome, Plants, Protein Kinases},
	issn = {0031-8655},
	author = {Roux, S J}
}
@article {2998,
	title = {Casein kinase II protein kinase is bound to lamina-matrix and phosphorylates lamin-like protein in isolated pea nuclei.},
	journal = {Proc Natl Acad Sci U S A},
	volume = {89},
	number = {18},
	year = {1992},
	month = {1992 Sep 15},
	pages = {8434-8},
	abstract = {A casein kinase II (CK II)-like protein kinase was identified and partially isolated from a purified envelope-matrix fraction of pea (Pisum sativum L.) nuclei. When [gamma-32P]ATP was directly added to the envelope-matrix preparation, the three most heavily labeled protein bands had molecular masses near 71, 48, and 46 kDa. Protein kinases were removed from the preparation by sequential extraction with Triton X-100, EGTA, 0.3 M NaCl, and a pH 10.5 buffer, but an active kinase still remained bound to the remaining lamina-matrix fraction after these treatments. This kinase had properties resembling CK II kinases previously characterized from animal and plant sources: it preferred casein as an artificial substrate, could use GTP as efficiently as ATP as the phosphoryl donor, was stimulated by spermine, was calcium independent, and had a catalytic subunit of 36 kDa. Some animal and plant CK II kinases have regulatory subunits near 29 kDa, and a lamina-matrix-bound protein of this molecular mass was recognized on immunoblot by anti-Drosophila CK II polyclonal antibodies. Also found associated with the envelope-matrix fraction of pea nuclei were p34cdc2-like and Ca(2+)-dependent protein kinases, but their properties could not account for the protein kinase activity bound to the lamina. The 71-kDa substrate of the CK II-like kinase was lamin A-like, both in its molecular mass and in its cross-reactivity with anti-intermediate filament antibodies. Lamin phosphorylation is considered a crucial early step in the entry of cells into mitosis, so lamina-bound CK II kinases may be important control points for cellular proliferation.},
	keywords = {Amino Acid Sequence, Casein Kinase II, Cell Compartmentation, Fabaceae, Lamin Type A, Lamins, Microscopy, Electron, Molecular Sequence Data, Nuclear Matrix, Nuclear Proteins, Peptides, Phosphorylation, Plants, Medicinal, Protein-Serine-Threonine Kinases},
	issn = {0027-8424},
	author = {Li, H and Roux, S J}
}
@article {3005,
	title = {Determination of cytoplasmic calcium concentration in Dryopteris spores: a developmentally non-disruptive technique for loading of the calcium indicator fura-2.},
	journal = {Planta},
	volume = {184},
	year = {1991},
	month = {1991},
	pages = {166-74},
	abstract = {Germination of Dryopteris spores is mediated by the physiologically active, far-red-absorbing form of phytochrome, Pfr, and external Ca2+ is necessary for the transduction of the light signal. Because knowledge about the cytoplasmic calcium ion concentration, [Ca2+]i, is of great importance for understanding the role of calcium during signal transduction, this value was measured using fura-2 in fern spores undergoing the normal developmental progression into germination. Fura-2 was loaded into the spores by electroporation, which does not disrupt the normal process of germination. The intensity of the fluorescence emission of the loaded fura-2 was analysed by a microspectrophotometric assay of single spores, and successful loading could be obtained by the application of ten electrical pulses (field strength 7.5 kV cm-1, half-life (time constant) 230 microseconds). Fura-2 was alternately excited by light of wavelengths 355 and 385 nm through an inverted fluorescence microscope, and the emitted fura-2 fluorescence was collected by a silicon-intensified video camera. The cytoplasmic calcium ion concentration was calculated from the ratio of the camera output obtained for both wavelengths and displayed by a pseudo-color technique. Spores responded to changes of the extracellular Ca2+ concentration, and this observation is considered as evidence that fura-2 is loaded into the cytoplasm. The substitution of a low external [Ca2+] (1 mM ethyleneglycol-bis(2-aminoethylether)-N,N,N{\textquoteright},N{\textquoteright}-tetraacetic acid (EGTA)) by 1 mM CaCl2 caused a fast increase of [Ca2+]i from approx. 50 nM to above 500 nM. In contrast, the subsequent substitution of CaCl2 by EGTA decreased [Ca2+]i again below 100 nM within 0.5 h. Furthermore, the application of ionomycin could initiate a change in [Ca2+]i according to the Ca2+ gradient established between the extracellular medium and cytoplasm. In spores sown on a Ca(2+) -free medium, [Ca2+]i, analysed in a buffer containing EGTA, was found to be around 50 nM during the first days of cultivation, independent of the irradiation protocol. However, if spores were grown in darkness on a Ca(2+) -containing medium and analysed in EGTA, [Ca2+]i was significantly higher (> or = 500 nM). In red-light-irradiated spores, [Ca2+]i was found to decrease with increasing time after irradiation, and was determined to be less than 100 nM when analysis was done 44 h after germination was initiated by the light treatment.},
	keywords = {Calcium, Chelating Agents, Cytoplasm, Electroporation, Fluorescent Dyes, Fura-2, Germination, Ionomycin, Light, Phytochrome, Plants, Signal Transduction, Spectrometry, Fluorescence, Spores},
	issn = {0032-0935},
	author = {Scheuerlein, R and Schmidt, K and Poenie, M and Roux, S J}
}
@article {3004,
	title = {Determination of cytoplasmic calcium concentration in Dryopteris spores : A developmentally non-disruptive technique for loading of the calcium indicator fura-2.},
	journal = {Planta},
	volume = {184},
	number = {2},
	year = {1991},
	month = {1991 May},
	pages = {166-74},
	abstract = {Germination of Dryopteris spores is mediated by the physiologically active, far-red-absorbing form of phytochrome, Pfr, and external Ca(2+) is necessary for the transduction of the light signal. Because knowledge about the cytoplasmic calcium ion concentration, [Ca(2+)]i, is of great importance for understanding the role of calcium during signal transduction, this value was measured using fura-2 in fern spores undergoing the normal developmental progression into germination. Fura-2 was loaded into the spores by electroporation, which does not disrupt the normal process of germination. The intensity of the fluorescence emission of the loaded fura-2 was analysed by a microspectrophotometric assay of single spores, and successful loading could be obtained by the application of ten electrical pulses (field strength 7.5 kV {\textperiodcentered} cm(-1), half-life (time constant) 230 μs). Fura-2 was alternately excited by light of wavelengths 355 and 385 nm through an inverted fluorescence microscope, and the emitted fura-2 fluorescence was collected by a silicon-intensified video camera. The cytoplasmic calcium ion concentration was calculated from the ratio of the camera output obtained for both wavelengths and displayed by a pseudo-color technique. Spores responded to changes of the extracellular Ca(2+) concentration, and this observation is considered as evidence that fura-2 is loaded into the cytoplasm. The substitution of a low external [Ca(2+)] (1 mM ethyleneglycol-bis(2-aminoethyl-ether) {ie166-01},N{\textquoteright}-tetraacetic acid (EGTA)) by 1 mM CaCl2 caused a fast increase of [Ca(2+)]i from approx. 50 nM to above 500 nM. In contrast, the subsequent substitution of CaCl2 by EGTA decreased [Ca(2+)]i again below 100 nM within 0.5 h. Furthermore, the application of ionomycin could initiate a change in [Ca2+]i according to the Ca(2+) gradient established between the extracellular medium and cytoplasm. In spores sown on a Ca(2+)-free medium, [Ca(2+)]i, analysed in a buffer containing EGTA, was found to be around 50 nM during the first days of cultivation, independent of the irradiation protocol. However, if spores were grown in darkness on a Ca(2+)-containing medium and analysed in EGTA, [Ca(2+)]i was significantly higher (≧ 500 nM). In red-light-irradiated spores, [Ca(2+)]i was found to decrease with increasing time after irradiation, and was determined to be less than 100 nM when analysis was done 44 h after germination was initiated by the light treatment.},
	issn = {0032-0935},
	doi = {10.1007/BF00197944},
	author = {Scheuerlein, R and Schmidt, K and Poenie, M and Roux, S J}
}
@article {3006,
	title = {Partial purification and characterization of a Ca(2+)-dependent protein kinase from pea nuclei.},
	journal = {Plant Physiol},
	volume = {96},
	year = {1991},
	month = {1991},
	pages = {720-7},
	abstract = {Almost all the Ca(2+)-dependent protein kinase activity in nuclei purified from etiolated pea (Pisum sativum, L.) plumules is present in a single enzyme that can be extracted from chromatin by 0.3 molar NaCl. This protein kinase can be further purified 80,000-fold by salt fractionation and high performance liquid chromatography, after which it has a high specific activity of about 100 picomoles per minute per microgram in the presence of Ca2+ and reaches half-maximal activation at about 3 x 10(-7) molar free Ca2+, without calmodulin. It is a monomer with a molecular weight near 90,000. It can efficiently use histone III-S, ribosomal S6 protein, and casein as artificial substrates, but it phosphorylates phosvitin only weakly. Its Ca(2+)-dependent kinase activity is half-maximally inhibited by 0.1 millimolar chlorpromazine, by 35 nanomolar K-252a and by 7 nanomolar staurosporine. It is insensitive to sphingosine, an inhibitor of protein kinase C, and to basic polypeptides that block other Ca(2+)-dependent protein kinases. It is not stimulated by exogenous phospholipids or fatty acids. In intact isolated pea nuclei it preferentially phosphorylates several chromatin-associated proteins, with the most phosphorylated protein band being near the same molecular weight (43,000) as a nuclear protein substrate whose phosphorylation has been reported to be stimulated by phytochrome in a calcium-dependent fashion.},
	keywords = {Calcium, Calmodulin, Cell Nucleus, Chromatin, Nuclear Proteins, Peas, Phosphorylation, Plant Proteins, Protein Kinase C, Protein Kinases},
	issn = {0032-0889},
	author = {Li, H and Dauwalder, M and Roux, S J}
}
@article {3003,
	title = {Phytochrome-mediated germination and early development in spores of Dryopteris filix-mas L.: phase-specific and non phase-specific inhibition by staurosporine.},
	journal = {J Plant Physiol},
	volume = {138},
	number = {6},
	year = {1991},
	month = {1991 Oct},
	pages = {747-51},
	abstract = {The alkaloid staurosporine, currently known as the most potent inhibitor of protein kinase C, PKC, was tested for its ability to inhibit phytochrome-mediated spore germination in Dryopteris filix-mas L., evaluated by the induction of chlorophyll synthesis. Approximately half-maximal inhibition was obtained at a concentration of 10(-5) M. This effect of staurosporine was phase-specific and was found during the same period in which the presence of extracellular calcium is necessary for realization of the light signal. Furthermore, the ability of staurosporine to prevent progression of a germinated spore into early gametophyte development, evaluated by the accumulation of chlorophyll, was examined. Again, staurosporine (10(-5) M) significantly diminished chlorophyll accumulation, determined quantitatively in vivo by single-cell measurements, in a non-phase specific way. The fact that the phase-specific inhibitory effect of staurosporine in preventing germination was coincident with the phase-specific requirement of Ca2+ suggests that both Ca2+ and staurosporine affect the same step in the signal-transduction chain. A phosphorylation event catalysed by PKC or any Ca2+ -dependent protein kinase is proposed as the target of staurosporine and Ca2+.},
	keywords = {Alkaloids, Calcium, Catalysis, Chlorophyll, Phosphorylation, Phytochrome, Plant Development, Plant Physiological Phenomena, Plants, Protein Kinase C, Spores, Staurosporine},
	issn = {0176-1617},
	author = {Haas, C J and Scheuerlein, R and Roux, S J}
}
@article {3007,
	title = {Partial purification and characterization of a Ca(2+)-dependent protein kinase from the green alga, Dunaliella salina.},
	journal = {Plant Physiol},
	volume = {94},
	year = {1990},
	month = {1990},
	pages = {143-50},
	abstract = {A calcium-dependent protein kinase was partially purified and characterized from the green alga Dunaliella salina. The enzyme was activated at free Ca2+ concentrations above 10(-7) molar. and half-maximal activation was at about 3 x 10(-7) molar. The optimum pH for its Ca(2+)-dependent activity was 7.5. The addition of various phospholipids and diolein had no effects on enzyme activity and did not alter the sensitivity of the enzyme toward Ca2+. The enzyme was inhibited by calmodulin antagonists, N-(6-aminohexyl)-1-naphthalene sulfonamide and N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide in a dose-dependent manner while the protein kinase C inhibitor, sphingosine, had little effect on enzyme activity up to 800 micromolar. Immunoassay showed some calmodulin was present in the kinase preparations. However, it is unlikely the kinase was calmodulin regulated, since it still showed stimulation by Ca2+ in gel assays after being electrophoretically separated from calmodulin by two different methods. This gel method of detection of the enzyme indicated that a protein band with an apparent molecular weight of 40,000 showed protein kinase activity at each one of the several steps in the purification procedure. Gel assay analysis also showed that after native gel isoelectric focusing the partially purified kinase preparations had two bands with calcium-dependent activity, at isoelectric points 6.7 and 7.1. By molecular weight, by isoelectric point, and by a comparative immunoassay, the Dunaliella kinase appears to differ from at least some of the calcium-dependent, but calmodulin and phospholipid independent kinases described from higher plants.},
	keywords = {Calcium, Calmodulin, Chlorophyta, Phospholipids, Phosphorylation, Plant Proteins, Protein Kinases},
	issn = {0032-0889},
	author = {Roux, S J}
}
@article {3010,
	title = {Calcium requirement of phytochrome-mediated fern-spore germination: no direct phytochrome-calcium interaction in the phytochrome-initiated transduction chain.},
	journal = {Planta},
	volume = {178},
	year = {1989},
	month = {1989},
	pages = {25-30},
	abstract = {Phytochrome-mediated germination of fern spores of Dryopteris paleacea Sw. was initiated by a saturating red-light (R) irradiation after 20 h of imbibition. For its realization external Ca2+ was required, with a threshold at a submicromolar concentration, and an optimum was reached around 10(-4) M. At concentrations > or = 10(-1) M only a reduced response was obtained, based probably on an unspecific osmotic or ionic effect. The germination response was inhibited by La3+, an antagonist of Ca2+. From these results it is concluded that Ca2+ influx from the medium into the spores may be an important event in phytochrome-mediated germination. In the absence of Ca2+ the R-stimulated system remained capable of responding to Ca2+, added as late as 40 h after R. Moreover, Ca2+ was effective even if added after the active form of phytochrome, Pfr, had been abolished by far-red (FR) 24 h after R. Thus, the primary effect of Pfr, that initiates the transduction chain, does not require calcium. "Coupling" of Pfr to subsequent dark reactions has been investigated by R-FR irradiations with various dark intervals. The resulting "escape kinetics" were characterized by a lag phase (6 h) and half-maximal escape from FR reversibility (19 h). These kinetics were not significantly changed by the presence or absence of calcium. Thus, direct interaction of Pfr and calcium is not a step in the transduction chain initiated by the active form of phytochrome.},
	keywords = {Calcium, Culture Media, Germination, Lanthanum, Light, Photoperiod, Phytochrome, Plant Physiological Phenomena, Plants, Signal Transduction, Spores, Time Factors},
	issn = {0032-0935},
	author = {Scheuerlein, R and Wayne, R and Roux, S J}
}
@article {3009,
	title = {Calcium requirement of phytochrome-mediated fern-spore germination: No direct phytochrome-calcium interaction in the phytochrome-initiated transduction chain.},
	journal = {Planta},
	volume = {178},
	number = {1},
	year = {1989},
	month = {1989 May},
	pages = {25-30},
	abstract = {Phytochrome-mediated germination of fern spores of Dryopteris paleacea Sw. was initiated by a saturating red-light (R) irradiation after 20 h of imbibition. For its realization external Ca(2+) was required, with a threshold at a submicromolar concentration, and an optimum was reached around 10(-4) M. At concentrations >=10(-1) M only a reduced response was obtained, based probably on an unspecific osmotic or ionic effect. The germination response was inhibited by La(3+), an antagonist of Ca(2+). From these results it is concluded that Ca(2+) influx from the medium into the spores may be an important event in phytochrome-mediated germination. In the absence of Ca(2+) the R-stimulated system remained capable of responding to Ca(2+), added as late as 40 h after R. Moreover, Ca(2+) was effective even if added after the active form of phytochrome, Pfr, had been abolished by far-red (FR) 24 h after R. Thus, the primary effect of Pfr, that initiates the transduction chain, does not require calcium. "Coupling" of Pfr to subsequent dark reactions has been investigated by R-FR irradiations with various dark intervals. The resulting "escape kinetics" were characterized by a lag phase (6 h) and half-maximal escape from FR reversibility (19 h). These kinetics were not significantly changed by the presence or absence of calcium. Thus, direct interaction of Pfr and calcium is not a step in the transduction chain initiated by the active form of photochrome.},
	issn = {0032-0935},
	doi = {10.1007/BF00392523},
	author = {Scheuerlein, R and Wayne, R and Roux, S J}
}
@article {3008,
	title = {Phytochrome induces changes in the immunodetectable level of a wall peroxidase that precede growth changes in maize seedlings.},
	journal = {Proc Natl Acad Sci U S A},
	volume = {86},
	year = {1989},
	month = {1989 Dec},
	pages = {9866-70},
	abstract = {The regulatory pigment phytochrome induces rapid and opposite growth changes in different regions of etiolated maize seedlings: it stimulates the elongation rate of coleoptiles and inhibits that of mesocotyls. As measured by a quantitative immunoassay, phytochrome also promotes rapid and opposite changes in the extractable content of a Mr 98,000 anionic isoperoxidase in the cell walls of these same organs: it induces a decrease of this peroxidase in coleoptiles and an increase in mesocotyls. The peroxidase changes precede the growth changes. As measured by video stereomicroscopy or a position transducer, red light (R), which photoactivates phytochrome, stimulates coleoptile elongation with a lag of about 15-20 min and suppresses mesocotyl growth with a lag of 45-50 min. R also induces a 50\% reduction in the extractable level of the anionic peroxidase in coleoptile walls in less than 10 min and a 40\% increase in the level of this peroxidase in mesocotyl walls within 30 min. Ascorbic acid, an inhibitor of peroxidase activity, blocks the effects of R on mesocotyl section growth. These results are relevant to hypotheses that postulate that certain wall peroxidases can participate in light-induced changes in growth rate by their effects on wall extensibility.},
	keywords = {Antibodies, Monoclonal, Cell Wall, Cotyledon, Immunoassay, Light, Peroxidases, Photic Stimulation, Phytochrome, Plant Stems, Time Factors, Zea mays},
	issn = {0027-8424},
	author = {Kim, S H and Shinkle, J R and Roux, S J}
}
@article {3011,
	title = {Early quantitative method for measuring germination in non-green spores of Dryopteris paleacea using an epifluorescence-microscope technique.},
	journal = {Physiol Plant},
	volume = {73},
	number = {4},
	year = {1988},
	month = {1988},
	pages = {505-11},
	abstract = {A method is described to determine germination by blue-light excited red fluorescence in the positively photoblastic spores of Dryopteris paleacea Sw. This fluorescence is due to chlorophyll as evidenced from 1) a fluorescence-emission spectrum in vivo, where a bright fluorescence around 675 nm is obtained only in red light (R)-irradiated spores and 2) in vitro measurements with acetone extracts prepared from homogenized spores. Significant amounts of chlorophyll can be found only in R-treated spores; this chlorophyll exhibits an emission band around 668 nm, when irradiated with 430 nm light at 21 degrees C. Compared to other criteria for germination, such as swelling of the cell, coat splitting, greening, and rhizoid formation, which require longer periods after induction for their expression, chlorophyll fluorescence can be used to quantify germination after two days. This result is confirmed by fluence-response curves for R-induced spore germination; the same relationship between applied R and germination is obtained by the evaluation with the epifluorescence method 2 days after the light treatment as compared with the evaluation with bright-field microscopy 5 days after the inducing R. Using this technique we show for the first time that Ca2+ contributes to the signal-transduction chain in phytochrome-mediated chlorophyll synthesis in spores of Dryopteris paleacea.},
	keywords = {Calcium, Chlorophyll, Darkness, Germination, Light, Microscopy, Fluorescence, Plant Physiological Phenomena, Plants, Spores},
	issn = {0031-9317},
	author = {Scheuerlein, R and Wayne, R and Roux, S J}
}
@article {3012,
	title = {Production and characterization of monoclonal antibodies to wall-localized peroxidases from corn seedlings.},
	journal = {Plant Physiol},
	volume = {88},
	year = {1988},
	month = {1988},
	pages = {1446-53},
	abstract = {A library of 22 hybridomas, which make antibodies to soluble wall antigens from the coleoptiles and primary leaves of etiolated corn (Zea mays L.) seedlings, was raised and cloned three times by limit dilution to assure monoclonal growth and stability. Two of these hybridomas made immunoglobulin G antibodies, designated mWP3 and mWP19, which both effectively immunoprecipitated peroxidase activity from crude and partially purified preparations of wall peroxidases. Direct peroxidase-binding assays revealed that both antibodies bound enzymes with peroxidase activity. As judged by immunoblot analyses, mWP3 recognized a Mr 98,000 wall peroxidase with an isoelectric point near 4.2, and mWP19 recognized a Mr 58,000 wall peroxidase. Immunogold localization studies showed both peroxidases are predominately in cell walls.},
	keywords = {Antibodies, Monoclonal, Blotting, Western, Cell Wall, Cotyledon, Electrophoresis, Polyacrylamide Gel, Hybridomas, Immunoglobulin G, Immunohistochemistry, Peroxidases, Plant Proteins, Precipitin Tests, Protein Binding, Zea mays},
	issn = {0032-0889},
	author = {Kim, S H and Terry, M E and Hoops, P and Dauwalder, M and Roux, S J}
}
@article {3015,
	title = {Cellular mechanisms controlling light-stimulated gravitropism: role of calcium.},
	journal = {CRC Crit Rev Plant Sci},
	volume = {5},
	number = {3},
	year = {1987},
	month = {1987},
	pages = {205-36},
	keywords = {Calcium, Gravitation, Gravitropism, Light, Plant Development, Plant Physiological Phenomena, Plants},
	issn = {0735-2689},
	doi = {10.1080/07352688709382240},
	author = {Roux, S J and Serlin, B S}
}
@article {3013,
	title = {Purification and partial characterization of a calmodulin-stimulated nucleoside triphosphatase from pea nuclei.},
	journal = {J Biol Chem},
	volume = {262},
	number = {22},
	year = {1987},
	month = {1987 Aug 5},
	pages = {10689-94},
	abstract = {A nucleoside triphosphatase/deoxynucleoside triphosphatase associated with the chromatin fraction from a highly purified preparation of pea nuclei has been isolated and characterized. The purified enzyme has a molecular weight of 47,000 as checked by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and it has an isoelectric point of 6.6. In the presence of divalent cations (Mg2+ = Mn2+ greater than Ca2+), this enzyme hydrolyzes nucleoside triphosphates or deoxynucleoside triphosphates. Hydrolysis is optimal at pH 7.5 and is significantly inhibited by relatively low concentrations of quercetin, but is not sensitive to vanadate, nitrate, or oligomycin. The enzyme has a rather broad nucleotide substrate specificity and has a Km for MgATP2- of 0.6 mM. The enzyme activity is stimulated over 3-fold by Ca2+ and calmodulin, and the stimulation is blocked by the Ca2+ chelator EGTA and by the calmodulin antagonists compound 48/80 and chlorpromazine.},
	keywords = {Adenosine Triphosphate, Calcium, Calmodulin, Cations, Divalent, Cell Nucleus, Electrophoresis, Polyacrylamide Gel, Fabaceae, Hydrogen-Ion Concentration, Isoelectric Point, Kinetics, Molecular Weight, Nucleoside-Triphosphatase, Phosphoric Monoester Hydrolases, Plants, Plants, Medicinal, Quercetin, Substrate Specificity},
	issn = {0021-9258},
	author = {Chen, Y R and Datta, N and Roux, S J}
}
@article {3014,
	title = {Spermine stimulation of a nuclear NII kinase from pea plumules and its role in the phosphorylation of a nuclear polypeptide.},
	journal = {Plant Physiol},
	volume = {84},
	year = {1987},
	month = {1987},
	pages = {1397-401},
	abstract = {We have previously demonstrated that spermine stimulates the phosphorylation of a 47 kilodalton nuclear polypeptide from pea plumules (N Datta, LK Hardison, SJ Roux 1986 Plant Physiol 82: 681-684). In this paper we report that spermine stimulates the activity of a cyclic AMP independent casein kinase, partially purified from a chromatin fraction of pea plumule nuclei. This effect of spermine was substrate specific; i.e. with casein as substrate, spermine stimulated the kinase activity, and with phosvitin as substrate, spermine completely inhibited the activity. The stimulation by spermine of the casein kinase was, in part, due to the lowering of the Mg2+ requirement of the kinase. Heparin could partially inhibit this casein kinase activity and spermine completely overcame this inhibition. By further purification of the casein kinase extract on high performance liquid chromatography, we fractionated it into an NI and an NII kinase. Spermine stimulated the NII kinase by 5- to 6-fold but had no effect on the NI kinase. Using [gamma-32P]GTP, we have shown that spermine promotes the phosphorylation of the 47 kilodalton polypeptide(s) in isolated nuclei, at least in part by stimulating an NII kinase.},
	keywords = {Casein Kinase II, Casein Kinases, Caseins, Cell Nucleus, DNA-Binding Proteins, Heparin, Magnesium, Nuclear Proteins, Peas, Phosphorylation, Phosvitin, Plant Proteins, Plant Shoots, Protein Kinases, Protein-Serine-Threonine Kinases, Seeds, Spermine, Substrate Specificity},
	issn = {0032-0889},
	author = {Datta, N and Schell, M B and Roux, S J}
}
@article {3020,
	title = {Characterization of nucleoside triphosphatase activity in isolated pea nuclei and its photoreversible regulation by light.},
	journal = {Plant Physiol},
	volume = {81},
	year = {1986},
	month = {1986},
	pages = {609-13},
	abstract = {A nucleoside triphosphatase (NTPase) present in highly purified preparations of pea nuclei was partially characterized. The activity of this enzyme was stimulated by divalent cations (Mg2+ = Mn2+ > Ca2+), but was not affected by the monovalent cations, Na+ and K+. The Mg(2+)-dependent activity was further stimulated by concentrations of Ca2+ in the low micromolar range. It could catalyze the hydrolysis of ATP, GTP, UTP, and CTP, all with a pH optimum of 7.5. The nuclear NTPase activity was not inhibited by vanadate, oligomycin, or nitrate, but was inhibited by relatively low concentrations of quercetin and the calmodulin inhibitor, compound 48/80. The NTPase was stimulated more than 50\% by red light, and this effect was reversed by subsequent irradiation with far-red light. The photoreversibility of the stimulation indicated that the photoreceptor for this response was phytochrome, an important regulator of photomorphogenesis and gene expression in plants.},
	keywords = {Acid Anhydride Hydrolases, Calcium, Calmodulin, Cell Nucleus, Chelating Agents, Egtazic Acid, Hydrogen-Ion Concentration, Hydrolysis, Infrared Rays, Light, Magnesium, Manganese, Nucleoside-Triphosphatase, p-Methoxy-N-methylphenethylamine, Peas, Phytochrome, Potassium, Quercetin, Sodium},
	issn = {0032-0889},
	author = {Chen, Y R and Roux, S J}
}
@article {3022,
	title = {Distribution of calmodulin in corn seedlings: immunocytochemical localization in coleoptiles and root apices.},
	journal = {Adv Space Res},
	volume = {6},
	number = {12},
	year = {1986},
	month = {1986},
	pages = {67-70},
	abstract = {Immunofluorescence techniques have been used to study the distribution of calmodulin in several tissues in etiolated corn (Zea mays, var. Bear Hybrid) seedlings. Uniform staining was seen in the background cytoplasm of most cell types. Cell walls and vacuoles were not stained. In coleoptile mesophyll cells the nucleoplasm of most nuclei was stained as was the stroma of most amyloplasts. The lumen border of mature tracheary elements in coleoptiles also stained. In the rootcap the most intensely stained regions were the cytoplasms of columella cells and of the outermost cells enmeshed in the layer of secreted slime. Nuclei in the rootcap cells did not stain distinctly, but those in all cell types of the root meristem did. Also in the root meristem, the cytoplasm of metaxylem elements stained brightly. These results are compared and contrasted with previous data on the localization of calmodulin in pea root apices and epicotyls and discussed in relation to current hypotheses on mechanisms of gravitropism.},
	keywords = {Calcium-Binding Proteins, Calmodulin, Cell Nucleus, Cell Wall, Cotyledon, Darkness, Gravitropism, Immunohistochemistry, Plant Proteins, Plant Roots, Plastids, Zea mays},
	issn = {0273-1177},
	author = {Dauwalder, M and Roux, S J}
}
@article {3019,
	title = {Distribution of calmodulin in pea seedlings: immunocytochemical localization in plumules and root apices.},
	journal = {Planta},
	volume = {168},
	year = {1986},
	month = {1986},
	pages = {461-70},
	abstract = {Immunofluorescence techniques have been used to study the distribution of calmodulin in several tissues in young etiolated pea (Pisum sativum L.) seedlings. A fairly uniform staining was seen in the nucleoplasm and background cytoplasm of most cell types. Cell walls and nucleoli were not stained. In addition, patterned staining reactions were seen in many cells. In cells of the plumule, punctate staining of the cytoplasm was common, and in part this stain appeared to be associated with the plastids. A very distinctive staining of amyloplasts was seen in the columella of the root cap. Staining associated with cytoskeletal elements could be shown in division stages. By metaphase, staining of the spindle region was quite evident. In epidermal cells of the stem and along the underside of the leaf there was an intense staining of the vacuolar contents. Guard cells lacked this vacuolar stain. Vacuolar staining was sometimes seen in cells of the stele, but the most distinctive pattern in the stele was associated with young conducting cells of the xylem. These staining patterns are consistent with the idea that the interactions of plastids and the cytoskeletal may be one of the Ca(2+)-mediated steps in the response of plants to environmental stimuli. Nuclear functions may also be controlled, at least in part, by Ca2+.},
	keywords = {Calcium, Calmodulin, Cytoplasm, Cytoskeleton, Immunohistochemistry, Microscopy, Electron, Microscopy, Fluorescence, Peas, Plant Leaves, Plant Roots, Plastids},
	issn = {0032-0935},
	author = {Dauwalder, M and Roux, S J and Hardison, L}
}
@article {3021,
	title = {Role of calcium ions in phytochrome responses: an update.},
	journal = {Physiol Plant},
	volume = {66},
	year = {1986},
	month = {1986},
	pages = {344-8},
	keywords = {Calcimycin, Calcium, Calmodulin, Chlorophyta, Chloroplasts, Germination, Infrared Rays, Ionophores, Light, Phosphorylation, Phytochrome, Plant Physiological Phenomena, Plants, Spores},
	issn = {0031-9317},
	author = {Roux, S J and Wayne, R O and Datta, N}
}
@article {3017,
	title = {Distribution of calmodulin in pea seedlings: Immunocytochemical localization in plumules and root apices.},
	journal = {Planta},
	volume = {168},
	number = {4},
	year = {1986},
	month = {1986 Sep},
	pages = {461-70},
	abstract = {Immunofluorescence techniques have been used to study the distribution of calmodulin in several tissues in young etiolated pea (Pisum sativum L.) seedlings. A fairly uniform staining was seen in the nucleoplasm and background cytoplasm of most cell types. Cell walls and nucleoli were not stained. In addition, patterned staining reactions were seen in many cells. In cells of the plumule, punctate staining of the cytoplasm was common, and in part this stain appeared to be associated with the plastids. A very distinctive staining of amyloplasts was seen in the columella of the root cap. Staining associated with cytoskeletal elements could be shown in division stages. By metaphase, staining of the spindle region was quite evident. In epidermal cells of the stem and along the underside of the leaf there was an intense staining of the vacuolar contents. Guard cells lacked this vacuolar stain. Vacuolar staining was sometimes seen in cells of the stele, but the most distinctive pattern in the stele was associated with young conducting cells of the xylem. These staining patterns are consistent with the idea that the interactions of plastids and the cytoskeletal system may be one of the Ca(2+)-mediated steps in the response of plants to environmental stimuli. Nuclear functions may also be controlled, at least in part, by Ca(2+).},
	issn = {0032-0935},
	doi = {10.1007/BF00392265},
	author = {Dauwalder, M and Roux, S J and Hardison, L}
}
@article {3018,
	title = {Light-induced import of the chromoprotein, phytochrome, into mitochondria.},
	journal = {Biochim Biophys Acta},
	volume = {848},
	year = {1986},
	month = {1986},
	pages = {372-7},
	abstract = {Mitochondria extracted from plants that were irradiated with actinic light in vivo have associated with them the chromoprotein, phytochrome. This phytochrome retains its native subunit size of 124 kDa after proteolytic treatment of the mitochondria with trypsin and chymotrypsin. This result suggests that phytochrome is not exposed on the outer surface of the outer mitochondrial membrane. Phytochrome, so protected, is not found to be associated with mitochondria derived from unirradiated plants. The possibility that the photoactivation of phytochrome induces a conformational change in its structure which facilitates its transport into the mitochondrion is discussed.},
	keywords = {Aprotinin, Avena sativa, Binding Sites, Chymotrypsin, Intracellular Membranes, Light, Mitochondria, Phytochrome, Plant Proteins, Trypsin, Trypsin Inhibitors},
	issn = {0006-3002},
	author = {Serlin, B S and Roux, S J}
}
@article {3016,
	title = {Polyamine stimulation of protein phosphorylation in isolated pea nuclei.},
	journal = {Plant Physiol},
	volume = {82},
	number = {3},
	year = {1986},
	month = {1986 Nov},
	pages = {681-4},
	abstract = {The phosphorylation of several proteins in isolated nuclei from Pisum sativum L. was stimulated by spermine. Although spermine increased the general protein phosphorylation by 10 to 20\%, it increased the phosphorylation of a 47 kilodalton polypeptide by 150\%. By comparison other polyamines, spermidine, putrescine, and cadavarine had far less effect on the phosphorylation of the 47 kilodalton or any other polypeptide. Sodium fluoride was able to inhibit the phosphorylation of the 47 kilodalton polypeptide in the control, implying the participation of protein phosphatase(s) in the phosphorylation of nuclear proteins. Spermine stimulated the phosphorylation of the 47 kilodalton polypeptide over the controls, even in the presence of NaF. This result indicates that spermine probably activates a nuclear kinase, a conclusion supported also by thiophosphorylation data. The inability of ethyleneglycol-bis (beta-amino-ethyl ether)-N, N{\textquoteright}-tetraacetic acid and Compound 48/80, a calmodulin antagonist, to inhibit this spermine stimulated phosphorylation renders improbable any role of calcium and calmodulin in mediating this response.},
	issn = {0032-0889},
	author = {Datta, N and Hardison, L K and Roux, S J}
}
@article {3025,
	title = {Cellular and subcellular localization of calcium in gravistimulated corn roots.},
	journal = {Protoplasma},
	volume = {129},
	year = {1985},
	month = {1985},
	pages = {137-48},
	abstract = {Antimonate staining procedures and energy dispersive X-ray micro-analytical techniques were used to determine the patterns of localization of calcium in nonstimulated and gravistimulated corn roots. In horizontally positioned roots within the region of the developing bend there was a change in the staining from that principally localized within cells of the stele to asymmetric staining within the vacuoles of the cortical cells along the upper root surface. There was little staining in the walls. The pattern observed is quite different from that seen in gravistimulated coleoptiles. Staining of mitochondria, plastids and Golgi stacks was seen in most cell types, but no asymmetry of staining was observed. In the rootcap where graviperception is thought to occur, there was little staining of any cellular organelles.},
	keywords = {Antimony, Calcium, Gravitation, Gravitropism, Microscopy, Electron, Plant Root Cap, Plant Roots, Spectrum Analysis, Staining and Labeling, Vacuoles, Zea mays},
	issn = {0033-183X},
	author = {Dauwalder, M and Roux, S J and Rabenberg, L K}
}
@article {3026,
	title = {Characterization of monoclonal antibodies to oat phytochrome by competitive radioimmunoassays and comparative immunoblots of phytochrome peptides.},
	journal = {Arch Biochem Biophys},
	volume = {236},
	number = {1},
	year = {1985},
	month = {1985 Jan},
	pages = {150-8},
	abstract = {A library of 50 hybridomas which make antibodies to oat phytochrome was produced from the fusion of spleen cells from immunized Balb/c mice with P3x63Ag8 myeloma cells. Hybridomas were selected in a medium containing hypoxanthine, aminopterin, and thymidine, and specific hybridomas were screened for production of antibodies to phytochrome using a solid-phase enzyme-linked immunoadsorbent assay which was antigen specific. Positive cultures were cloned three times by limit dilution to assure monoclonal growth and stability. Specificity toward phytochrome was established by Western blot analysis and immunoprecipitation. Epitope specificity of nine monoclonal antibodies was determined by competitive inhibition radioimmunoassays and/or comparative immunoblots of tryptic peptides of phytochrome.},
	keywords = {Animals, Antibodies, Monoclonal, Antibody Specificity, Binding Sites, Antibody, Binding, Competitive, Cereals, Chemical Phenomena, Chemical Precipitation, Chemistry, Collodion, Enzyme-Linked Immunosorbent Assay, Female, Hybridomas, Immunochemistry, Male, Mice, Mice, Inbred BALB C, Peptide Fragments, Phytochrome, Plant Proteins, Radioimmunoassay, Trypsin},
	issn = {0003-9861},
	author = {Silberman, L G and Datta, N and Hoops, P and Roux, S J}
}
@article {3023,
	title = {Immunocytochemical localization of calmodulin in pea root caps and plumules and its relevance to hypotheses on gravitropism.},
	journal = {Physiologist},
	volume = {28},
	number = {6 Suppl},
	year = {1985},
	month = {1985 Dec},
	pages = {S115-6},
	keywords = {Calmodulin, Fabaceae, Gravitation, Histocytochemistry, Plants, Plants, Medicinal},
	issn = {0031-9376},
	author = {Roux, S J and Dauwalder, M}
}
@article {3024,
	title = {Phytochrome and calcium stimulation of protein phosphorylation in isolated pea nuclei.},
	journal = {Biochem Biophys Res Commun},
	volume = {128},
	number = {3},
	year = {1985},
	month = {1985 May 16},
	pages = {1403-8},
	abstract = {The phosphorylation of several proteins in pea nuclei was promoted by Ca2+ and by red light. The red light-induced stimulation was reversed by far-red light, indicating that the photoreceptor modulating this response was the photochromic pigment, phytochrome. Both the red light and the Ca2+-promoted enhancement of phosphorylation were inhibited by the calcium chelator, ethylene glycol bis(beta-aminoethyl ether) N, N{\textquoteright}-tetraacetic acid, and by the calmodulin inhibitors, chlorpromazine and compound 48/80.},
	keywords = {Calcium, Fabaceae, Light, Nucleoproteins, Phosphorylation, Phytochrome, Plant Proteins, Plants, Medicinal},
	issn = {0006-291X},
	author = {Datta, N and Chen, Y R and Roux, S J}
}
@article {3031,
	title = {Ca2+ and phytochrome action in plants.},
	journal = {Bioscience},
	volume = {34},
	number = {1},
	year = {1984},
	month = {1984 Jan},
	pages = {25-9},
	abstract = {Red light initiates many important morphogenetic responses in plants through the mediation of the pigment, phytochrome. How phytochrome promotes photomorphogenesis is unknown. The evidence that photoactivated phytochrome initiates calcium fluxes in cells is reviewed and how these fluxes could regulate several known red-light induced effects in plants is discussed.},
	keywords = {Calcium, Calcium-Binding Proteins, Calcium-Transporting ATPases, Calmodulin, Eukaryota, Infrared Rays, Light, Phosphotransferases (Alcohol Group Acceptor), Phytochrome, Plant Physiological Phenomena, Plants, Signal Transduction},
	issn = {0006-3568},
	author = {Roux, S J}
}
@article {3029,
	title = {Characterization of oat calmodulin and radioimmunoassay of its subcellular distribution.},
	journal = {Plant Physiol},
	volume = {75},
	number = {2},
	year = {1984},
	month = {1984 Jun},
	pages = {382-6},
	abstract = {A protein identifiable as calmodulin has been isolated from oat (Avena sativa, var Garry) tissues. This protein is relatively heat stable, binds to hydrophobic gels, and phenothiazines in a calcium-dependent fashion, and binds to antibody to rat testes calmodulin. Based on its migration on sodium dodecyl sulfate-polyacrylamide gels, ultraviolet absorption spectrum, and amino acid composition, oat calmodulin is essentially identical to calmodulin isolated from other higher plants. Radioimmunoassays indicate that calmodulin is associated with isolated oat protoplasts, mitochondria, etioplasts, and nuclei and also appears to be a component of oat cell wall fractions.},
	issn = {0032-0889},
	author = {Biro, R L and Daye, S and Serlin, B S and Terry, M E and Datta, N and Sopory, S K and Roux, S J}
}
@article {3030,
	title = {Modulation of oat mitochondrial ATPase activity by CA2+ and phytochrome.},
	journal = {Plant Physiol},
	volume = {74},
	number = {4},
	year = {1984},
	month = {1984 Apr},
	pages = {827-33},
	abstract = {The activity of a Mg(2+)-dependent ATPase present in highly purified preparations of Avena mitochondria was photoreversibly modulated by red/far-red light treatments. These results were obtained either with mitochondria isolated from plants irradiated with white light prior to the extraction or with mitochondria isolated from unirradiated plants only when purified phytochrome was exogenously added to the reaction mixture. Red light, which converts phytochrome to the far red-absorbing form (Pfr) depressed the ATPase activity, and far-red light reversed this effect. Addition of exogenous CaCl2 also depressed the ATPase activity, and the kinetics of inhibition were similar to the kinetics of the Pfr effects on the ATPase. The calcium chelator, ethyleneglycol-bis(beta-amino-ethyl ether)-N,N{\textquoteright} -tetraacetic acid, blocked the effects of both CaCl2 and Pfr on the ATPase. These results are consistent with the interpretation that Pfr promotes a release of Ca2+ from the mitochondrial matrix, thereby inducing an increase in the concentration of intermembranal and extramitochondrial Ca2+.},
	keywords = {Adenosine Triphosphatases, Avena sativa, Ca(2+) Mg(2+)-ATPase, Calcium, Egtazic Acid, Infrared Rays, Light, Magnesium, Mitochondria, Phytochrome},
	issn = {0032-0889},
	author = {Serlin, B S and Sopory, S K and Roux, S J}
}
@article {3028,
	title = {Inhibition of gravitropism in oat coleoptiles by the calcium chelator, ethyleneglycol-bis-(beta-aminoethyl ether)-N,N{\textquoteright}-tetraacetic acid.},
	journal = {Physiol Plant},
	volume = {61},
	number = {3},
	year = {1984},
	month = {1984 Jul},
	pages = {449-54},
	abstract = {A treatment period as brief as 8 h in 10(-3) M EGTA completely blocks gravitropism in 70-80\% of the treated coleoptiles of oats (Avena sativa L. cv. Garry) without inhibiting growth. Only about 10\% of the plants perfused in water failed to exhibit gravitropism. Subsequent perfusion of EGTA-treated plants with calcium completely restores gravitropism; post-perfusion with water does not. After perfusion in water for 10 h, gravistimulated oat coleoptile segments show the same asymmetry of 45Ca distribution as reported earlier for non-perfused coleoptiles and sunflower hypocotyls. The degree of this asymmetry is reduced in those coleoptiles partially inhibited by perfusion in EGTA and is essentially absent in those coleoptiles completely inhibited by EGTA. The fact that calcium reverses the inhibitory effects of EGTA on gravitropism indicates that the inhibition was probably due to a reduction in the availability of free calcium required for one or more of the transduction steps of gravitropism.},
	keywords = {Avena sativa, Calcium, Calcium Chloride, Chelating Agents, Cotyledon, Dose-Response Relationship, Drug, Egtazic Acid, Gravitropism, Time Factors},
	issn = {0031-9317},
	author = {Daye, S and Biro, R L and Roux, S J}
}
@article {3027,
	title = {Modulation of chloroplast movement in the green alga Mougeotia by the Ca2+ ionophore A23187 and by calmodulin antagonists.},
	journal = {Proc Natl Acad Sci U S A},
	volume = {81},
	number = {20},
	year = {1984},
	month = {1984 Oct},
	pages = {6368-72},
	abstract = {The Ca2+ ionophore A23187 can induce chloroplast rotation within a single nonirradiated Mougeotia cell. The induced turning was dependent on the position of ionophore application and Ca2+ in the external medium. The role of calmodulin in mediating light-induced chloroplast rotation in the alga Mougeotia was investigated by using the paired calmodulin-antagonist drugs W5-W7 and W12-W13. In each pair, the antagonist with the greater affinity for calmodulin had the greater inhibitor effect on the phytochrome-controlled light response. These results support the hypothesis that calcium functions as a chemical messenger to couple the stimulus of phytochrome photoactivation with physiological responses in plants.},
	keywords = {Actin Cytoskeleton, Calcimycin, Calcium, Calmodulin, Chlorophyta, Chloroplasts, Ionophores, Light, Phytochrome, Rotation, Signal Transduction, Valinomycin},
	issn = {0027-8424},
	author = {Serlin, B S and Roux, S J}
}
@article {3033,
	title = {Calcium movements and the cellular basis of gravitropism.},
	journal = {Adv Space Res},
	volume = {3},
	number = {9},
	year = {1983},
	month = {1983},
	pages = {221-7},
	abstract = {An early gravity-transduction event in oat coleoptiles which precedes any noticeable bending is the accumulation of calcium on their prospective slower-growing side. Sub-cellular calcium localization studies indicate that the gravity-stimulated redistribution of calcium results in an increased concentration of calcium in the walls of responding cells. Since calcium can inhibit the extension growth of plant cell walls, this selective accumulation of calcium in walls may play a role in inducing the asymmetry of growth which characterizes gravitropism. The active transport of calcium from cells into walls is performed by a calcium-dependent ATPase localized in the plasma membrane. Evidence is presented in support of the hypothesis that this calcium pump is regulated by a feed-back mechanism which includes the participation of calmodulin.},
	keywords = {Avena sativa, Calcium, Calcium-Transporting ATPases, Calmodulin, Cell Membrane, Cotyledon, Gravitropism, Microscopy, Electron, Phagosomes, Protoplasts, Signal Transduction},
	issn = {0273-1177},
	author = {Roux, S J and Biro, R L and Biro, R L}
}
@article {3032,
	title = {Cellular and subcellular localization of calcium in gravistimulated oat coleoptiles and its possible significance in the establishment of tropic curvature.},
	journal = {Planta},
	volume = {157},
	number = {6},
	year = {1983},
	month = {1983 May},
	pages = {481-92},
	abstract = {Light-and electron-microscopic studies of the distribution of calcium in gravitropically responding oat (Avena sativa L. cv. "Garry") coleoptiles are described. A modification of the antimonate precipitation procedure was used to localize tissue calcium in situ. An accumulation of Ca in the upper halves of horizontal, gravistimulated coleoptiles is seen within 10 min of stimulus onset. A pronounced redistribution of Ca to the upper side occurs within 30 min; although the localization of this cation is not uniform along the organ axis and in the apical region, Ca appears to accumulate along the lower side. The observed asymmetric distribution of Ca in these tissues precedes large-scale visible bending by 20-30 min, but is temporally well-correlated with differential growth responses in the coleoptile, as measured by more sensitive quantitative techniques. Gravitropic curvature is well developed by 3 h and is accompanied by further redistribution of Ca to tissues along the upper coleoptile half, centered around the bend. Ultrastructural localization studies indicate that Ca asymmetry results primarily from changes in the distribution of Ca within the apoplastic compartment. Large amounts of Ca accumulate at the cuticle in epidermal cell walls and in the walls of the underlying parenchyma cells at the upper side of the organ in the region of maximal bending. The differential growth response resulting in the establishment of gravitropic curvature may largely be the consequence of antagonistic effects of Ca on auxin-mediated cell wall loosening and elongation growth processes at the upper side of the organ.},
	issn = {0032-0935},
	doi = {10.1007/BF00396878},
	author = {Slocum, R D and Roux, S J}
}
@article {3034,
	title = {A possible role for Ca2+ in mediating phytochrome responses.},
	journal = {Symp Soc Exp Biol},
	volume = {36},
	year = {1983},
	month = {1983},
	pages = {561-80},
	keywords = {Binding Sites, Calcium, Calcium-Transporting ATPases, Calmodulin, Cell Membrane, Cell Membrane Permeability, Light, Lipid Bilayers, Liposomes, Mitochondria, NAD, Phytochrome, Plant Proteins, Plants},
	issn = {0081-1386},
	author = {Roux, S J}
}
@article {3035,
	title = {An improved method for the subcellular localization of calcium using a modification of the antimonate precipitation technique.},
	journal = {J Histochem Cytochem},
	volume = {30},
	number = {7},
	year = {1982},
	month = {1982 Jul},
	pages = {617-29},
	abstract = {A new variation of the antimonate precipitation technique, employing tannic acid in the primary aldehyde-antimonate fixative, is described for use in the subcellular localization of calcium in various tissues. Chelation studies and electron microscopic, X-ray microanalytical studies of antimonate precipitates in etiolated oat tissues indicate that calcium is the major cation localized using the present experimental protocol. Preservation of ultrastructural morphology in these tissues is greatly improved over that observed in tissues fixed with conventional antimonate-aldehyde or antimonate-osmium fixatives. The regularity and reproducibility of tissue precipitate patterns suggests that 1) penetration of the tissue by the fixative, and subsequent precipitation of calcium, is rapid and uniform and 2) ion displacement during sample preparation is negligible. Calcium appears to be immobilized efficiently in situ, with greater than 90\% 45Ca retention in radiolabeled tissues prepared for electron microscopy. Quantitative aspects of calcium precipitation by antimonate in 45Ca-labeled CaCl2 solutions were examined over a wide range of calcium concentrations. Precipitation was essentially linear over the expected range of biological concentrations of calcium. Furthermore, the 3:1 antimonate to calcium ratio estimated for test tube precipitates was also established for Sb/Ca in tissue precipitates analyzed using energy dispersive x-ray microanalytical (EDX) techniques. These observations suggest that the present technique is potentially useful in the semiquantitative estimation of tissue calcium levels.},
	keywords = {Animals, Antimony, Calcium, Cell Line, Cereals, Chemical Precipitation, Cricetinae, Kidney, Microscopy, Electron, Plants, Staining and Labeling, Subcellular Fractions},
	issn = {0022-1554},
	author = {Slocum, R D and Roux, S J}
}
@article {3036,
	title = {Phytochrome induces photoreversible calcium fluxes in a purified mitochondrial fraction from oats.},
	journal = {Proc Natl Acad Sci U S A},
	volume = {78},
	number = {1},
	year = {1981},
	month = {1981 Jan},
	pages = {283-7},
	abstract = {Previous studies have indicated that phytochrome regulates Ca(2+) fluxes across the plasma membrane of plant cells. In this study we investigated whether phytochrome can also regulate such fluxes across mitochondrial membranes, using the Ca(2+)-sensitive dye murexide to monitor the uptake and release of Ca(2+) by mitochondria. The results showed that Ca(2+) fluxes in these organelles could be photoreversibly altered, red light diminishing the net uptake rate and far-red light restoring this rate to its dark control level. Treatment of the mitochondria with ruthenium red blocked their Ca(2+) uptake. In the presence of this inhibitor, red light induced a net efflux of Ca(2+) from the mitochondria, and subsequent far-red light reduced this efflux to nearly zero, the dark control level. Light-induced rate changes in Ca(2+) flux, both with and without the inhibitor, persisted for several minutes in the dark and remained photoreversible through several irradiations for as long as 30 min. The purity of the mitochondrial preparation was judged to be about 80\% by electron microscopic morphometry; most of the phytochrome present was localized on the mitochondria in the preparation by using immunocytochemical methods. Taken together with previous findings, the results suggest that red light activation of phytochrome would initiate an increase in the cytosolic Ca(2+) concentration. The results are integrated with the fact that calmodulin is a component of plant cell cytoplasms to construct a model postulating that phytochrome directs photomorphogenesis in part through its regulation of Ca(2+) and calmodulin-controlled enzyme activities.},
	issn = {0027-8424},
	author = {Roux, S J and McEntire, K and Slocum, R D and Cedel, T E and Hale, C C}
}
@article {3037,
	title = {Photoreversible calcium fluxes induced by phytochrome in oat coleoptile cells.},
	journal = {Plant Physiol},
	volume = {65},
	number = {4},
	year = {1980},
	month = {1980 Apr},
	pages = {658-62},
	abstract = {The chromometallic dye murexide was used to measure photoreversible Ca fluxes in apical tips of etiolated oat coleoptiles and in suspension cultures of protoplasts derived from the coleoptile segments. Phytochrome presence in the protoplasts was indicated by a repeatably photoreversible DeltaA(725 - 800 nm) of >0.001 A centimeters(-1), recorded on a dual wavelength spectrophotometer. Concentrations of Ca in the solution bathing the cells were observed to change photoreversibly, red irradiation inducing an increase in the medium Ca concentration and subsequent farred irradiation inducing a decrease down to near dark control levels. These changes could be measured in media with or without exogenously added Ca. Protoplasts from green primary leaves of oat, which had no spectro-photometrically detectable phytochrome, showed no photoreversible Ca fluxes when measured by the same method. These data imply that red light induces an efflux of Ca from phytochrome-containing cells and that far red light can reverse this change by promoting a Ca reentry into these cells.},
	issn = {0032-0889},
	author = {Hale, C C and Roux, S J}
}
@article {3038,
	title = {Use of I-labeled phytochrome to quantitate phytochrome binding to membranes of Avena sativa.},
	journal = {Proc Natl Acad Sci U S A},
	volume = {74},
	number = {10},
	year = {1977},
	month = {1977 Oct},
	pages = {4439-43},
	abstract = {Purified oat phytochrome was labeled with (125)I without altering the photoreversibility or absorbance properties of the pigment. The radiolabeled phytochrome was used in experiments in vitro to quantitate the binding of the pigment to both crude and purified membrane preparations from oat tissue. After the membranes were allowed to react with (125)I-labeled phytochrome, washed free of unbound material, and pelleted, they were found to have significant levels of radioactivity bound to them. Qualitative identification of phytochrome as the bound radioactive species was confirmed by autoradiography of sodium dodecyl sulfate gels after electrophoresis of the proteins contained in the washed membranes. Data supporting the specificity of the binding are that the binding shows saturation kinetics and that unlabeled phytochrome, but not bovine serum albumin, will competitively inhibit the binding of labeled phytochrome. This technique permits the detection of less than a nanogram of phytochrome and provides a new method for quantifying bound phytochrome that is independent of the spectral detectability of the pigment. It should be useful in elucidating the nature of phytochrome attachment to cellular membranes.},
	issn = {0027-8424},
	author = {Georgevich, G and Cedel, T E and Roux, S J}
}
@article {3039,
	title = {Photoreversible conductance changes induced by phytochrome in model lipid membranes.},
	journal = {Proc Natl Acad Sci U S A},
	volume = {70},
	number = {3},
	year = {1973},
	month = {1973 Mar},
	pages = {762-4},
	abstract = {The plant protein phytochrome induces photoreversible conductance changes when added to a black lipid membrane made from oxidized cholesterol. The conductance of the phytochrome-modified membrane is increased by red-light illumination but is decreased by illumination with far-red light. Denatured phytochrome does not affect the conductance of the model membrane.},
	keywords = {Cholesterol, Electric Conductivity, Membranes, Artificial, Permeability, Photochemistry, Plant Proteins},
	issn = {0027-8424},
	author = {Roux, S J and Yguerabide, J}
}
@article {3040,
	title = {Chemical evidence for conformational differences between the red- and far-red-absorbing forms of oat phytochrome.},
	journal = {Biochemistry},
	volume = {11},
	number = {10},
	year = {1972},
	month = {1972 May 9},
	pages = {1930-6},
	keywords = {Acetamides, Aldehydes, Alkylation, Amino Acids, Chemical Phenomena, Chemistry, Chromatography, Gel, Chromatography, Paper, Electrophoresis, Paper, Infrared Rays, Iodoacetates, Light, Lysine, Mercaptoethanol, Nitrobenzenes, Oxidation-Reduction, Peptides, Pigments, Biological, Plant Proteins, Protein Conformation, Radiation Effects, Sulfonic Acids, Trypsin},
	issn = {0006-2960},
	author = {Roux, S J}
}
@article {3041,
	title = {The effect of glutaraldehyde and two monoaldehydes on phytochrome.},
	journal = {Arch Biochem Biophys},
	volume = {131},
	number = {2},
	year = {1969},
	month = {1969 May},
	pages = {423-9},
	keywords = {Acetaldehyde, Aldehydes, Chemical Phenomena, Chemistry, Chromatography, Gel, Formaldehyde, Glutarates, Pigments, Biological, Plant Extracts, Plant Growth Regulators, Plant Proteins, Spectrum Analysis, Sulfites},
	issn = {0003-9861},
	author = {Roux, S J and Hillman, W S}
}
