| Siderophores are low molecular weight iron-chelators produced by bacteria under iron-limited conditions such as in seawater. Only a modest number of marine siderophore structures have been characterized. The amonabactin sulfonates are a new suite of siderophores isolated from Pseudomonas stutrzeri VS05-10, a bacterium collected from the surface of basalts near the underwater volcano Vailulu'u Seamount. The amonabactin sulfonates are speculated to be involved in dissolution of iron-bearing minerals on basalts, thus enabling microbial growth under this unique environment. The amphi-enterobactins are a suite of siderophores isolated from marine bacterium Vibrio sp. R5, collected from seawater off the shore of Honduras. The structures of the amphi-enterobactins are strikingly similar to enterobactin, a nonamphiphilic siderophore produced by enteric bacteria. The structures of amonbactin sulfonates and amphi-enterobactins were elucidated by a combination of mass spectrometry, chemical analyses, and nuclear magnetic resonance spectrometry.;The biosynthetic genes of siderophores found in marine bacterium Vibrio sp. DS40M5 were also investigated. These siderophores include aerobactin and the amphiphilic suite of siderophores, the ochrobactins. Only one siderophore biosynthetic gene cluster was identified in Vibrio sp. DS40M5, thus suggesting that the biosynthetic pathways are shared between aerobactin and the ochrobactins. Finally, biosynthesis of a cyclic bromoterpenoid, by vanadium bromoperoxidase was investigated. The cyclic bromoterpenoid was structurally related to many known marine natural products with known bioactive properties. |
