Haygood, M. G. Scripps Institution of Oceanography, mhaygood@ucsd.edu
Edwards, D. G. Scripps Institution of Oceanography, dedwards@ucsd.edu
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SIDEROPHORE PRODUCTION BY MARINE HETEROTROPHIC BACTERIA
 
Recent research has shown that most of the iron in seawater is complexed by organic ligands, a condition that may affect the availability of iron to the biota. Siderophores from marine bacteria could contribute to the iron ligand pool. We have undertaken a survey of siderophore production by heterotrophic marine isolates, focusing on environmentally relevant organisms. We investigated strains that are as closely related as possible to sequences that appear in molecular surveys, and strains from groups whose siderophores have not been previously studied. Priority groups include members of the Cytophaga/Flexibacter group, marine alpha proteobacteria, marine Gram-positive bacteria and Southern Ocean psychrophiles. We assayed 67 strains for siderophore production using the chrome azurol S (CAS) assay on broth cultures. 28 of the 67 assayed are positive for siderophore production. Some of the negative strains might produce siderophores with further medium optimization. We sequenced the small subunit (16S) rRNA genes of these 28 to identify phylogenetic affiliation and determine whether they are similar to environmental sequences. With this information we have prioritized the strains for siderophore purification and structure determination. Six priority strains have been scaled up and HPLC studies show that the compounds produced are diverse.
 
Day: Wednesday, Feb. 3
Time: Poster
Location: Sweeney Center
 
Code: SS28WE0469S