Wu, L. Center for Microbial Ecology, Michigan State University, wul@ornl.gov
Zhou, J. Oak Ridge National Laboratory, zhouj@ornl.gov
Palumbo, A. V. Oak Ridge National Laboratory, palumboav@ornl.gov
Devol, A. School of Oceanography,, devol@u.washington.edu
Tiedje, J. M. Center for Microbial Ecology, tiedjej@pilot.msu.edu

To help in the understanding of the microbial processes, mechanisms, and organisms that control the dynamics of denitrification in the marine environment, we are examining the diversity of denitrification enzymes. Seventeen different denitrifiers were isolated from sediment samples collected off the coast of Washington State at six stations that ranged in overlying water depth from 100 to 2,500 m. PCR amplification with primers specific to heme- or copper-containing nitrite reductase genes indicated that 12 of the isolates had heme-containing nitrite reductase and 5 of them had copper-containing nitrite reductase genes. 16S rRNA gene-based phylogenetic analyses showed that 9 of the strains were closely related to Pseudomonas stutzeri with the similarities of 98-99%. Two strains were closely related to Marinobacter species with similarities of 95-96%, and one isolate was 98% similar to Halomonas variabilis. The remaining two strains were 98% similar to each other and 87% similar to Azospirillum lipoferum, suggesting that these isolates may represent a novel group of marine denitrifiers. A copper-containing nitrite reductase gene was detected in one of the novel strains but not in the other although they were phylogenetically similar.
Day: Friday, Feb. 5
Time: 10:45 - 11:00am
Location: Sweeney Center
Code: CS55FR1045S