Gonzalez, J. M. University of Georgia, gonzalez@arches.uga.edu
Kiene, R. M. Department of Marine Sciences, rkiene@jaguar1.usouthal.edu
Moran, M. University of Georgia, mmoran@arches.uga.edu

 
POSSIBLE ROLE IN THE DMSP/DMS CYCLE OF A NUMERICALLY IMPORTANT GROUP OF BACTERIA IN THE ALPHA-SUBCLASS OF THE PROTEOBACTERIA
 
A group of 15 marine isolates were tested for their ability to transform DMSP and DMS. The isolates were chosen because they represent the Marine Alpha cluster, a group of marine bacteria in the alpha subclass of the Proteobacteria, related to the genus Roseobacter, that is numerically important in water and sediments from estuarine Georgia and other coastal environments. The isolates were readily obtained on oligotrophic seawater plates inoculated directly from coastal seawater. They show high 16S rDNA sequence affinities to numerous seawater clones obtained from coastal seawater by PCR amplification. All 15 isolates were able to degrade DMSP, and in some cases both pathways for degradation (demethylation and cleavage) were found in the same organism. One isolate oxidized DMS to DMSO, whereas the others degraded DMS to methanethiol. DMSP and DMS enrichment cultures inoculated with coastal seawater showed an increase in the contribution of the Marine Alpha cluster, presumably because organic sulfur metabolism is characteristic of this group. We hypothesize that Marine Alpha bacteria may play an important role in the DMSP/DMS cycle in the marine environment. The organic sulfur transformations described for these isolates are similar to transformations observed in seawater by natural marine communities.
 
Day: Friday, Feb. 5
Time: 11:45 - 12:00pm
Location: Sweeney Center
 
Code: SS37FR1145S