Publications by Year: 1984

Aerobactin, a hydroxamate iron transport compound, is synthesized by some, but not all, Shigella species. Conjugation and hybridization studies indicated that the genes for the synthesis and transport of aerobactin are linked and are found on the chromosome of Shigella flexneri, S. boydii, and S. sonnei. The genes were not found in S. dysenteriae. A number of aerobactin synthesis mutants and transport mutants have been isolated. The most common mutations are deletions of the biosynthesis or biosynthesis and transport genes. The Shigella aerobactin genes share considerable homology with the E. coli ColV aerobactin genes. On the ColV plasmid and in the Shigella chromosome, the aerobactin genes are associated with a repetitive sequence which has been identified as IS1.

A novel siderophore (microbial iron transport compound) has been isolated from low iron cultures of Vibrio cholerae. Belonging to the catecholamide family of chelators, it has been shown to contain three residues of 2,3-dihydroxybenzoic acid and two residues of threonine. Both threonine moieties are present in the form of oxazoline rings. Furthermore, the polyamine backbone of the molecule was proved to be not spermidine, but the rare N-(3-aminopropyl)-1,3-diaminopropane, norspermidine. The structure of the new siderophore has been determined to be N-[3-(2,3-dihydroxybenzamido)propyl]-1, 3-bis[2,3-dihydroxyphenyl)-trans-5-methyl-2-oxazoline-4-carboxamido]prop ane. The compound has been given the trivial name vibriobactin. Mutants defective in the synthesis and utilization of vibriobactin were isolated. In an iron-limited environment V. cholerae was found to respond more strongly to vibriobactin, agrobactin, and ferrichrome than to enterobactin.