Martinez, J. S. University of California Santa Barbara, jmartinez@ultra.chem.ucsb.edu
Zhang, G. S. University of California Santa Barbara,
Holt, P. D. University of California Santa Barbara,
Haygood, M. G. Scripps Institution of Oceanography,
Butler, A. University of Califoria Santa Barbara, butler@ultra.chem.ucsb.edu

 
NEW SIDEROPHORES FROM MARINE HETEROTROPHIC BACTERIA
 
Marine bacterial growth depends in part upon the availability of iron, which is known to be an essential requirement for most microorganisms. Although heterotrophic bacteria require conditions of up to one micromolar iron for growth, the total amount of iron in surface ocean water is subnanomolar. This limiting amount of iron has implications in the biogeochemical cycling of carbon and in limited phytoplankton growth. Marine bacteria can successfully compete for this limited nutrient using a specialized iron transport system, including the production and release of siderophores (i.e. high-affinity iron (III) uptake ligands) which mediate iron transport into the cell by specific membrane receptor proteins and transport systems. We are investigating the processes by which marine bacteria aquire iron, in particular the nature of siderophores produced by open ocean and coastal isolates. Recently we have purified and characterized three sets of siderophores produced from different bacteria. Two of these sets, the marinobactins and aquachelins, contain mixed ligands consisting of two hydroxamic acid moieties and one alpha-hydroxy acid moiety. The structural elucidation, iron binding capabilities and the mode of biological function for the siderophores will be presented. SS28, SS38, CS17 Poster
 
Day: Wednesday, Feb. 3
Time: Poster
Location: Sweeney Center
 
Code: SS28WE0581S