Zani, S. Rensselaer Polytechnic Institute, zanis@rpi.edu
Mellon, M. Rensselaer Polytechnic Institute, mellom@rpi.edu
Allen, A. E. Skidaway Institute of Oceaography, Aallen@skio.peachnut.edu
Booth, M. G. Skidaway Institute of Oceaography, Aallen@skio.peachnut.edu
Frischer, M. E. Skidaway Institute of Oceanography, frischer@skio.peachnut.edu
Zehr, . P. Rensselaer Polytechnic Institute, zehrj@rpi.edu

 
CHARACTERIZATION OF ASSIMILATORY NITRATE REDUCTASE GENES OF MARINE MICROBIAL COMMUNITIES
 
Microbial production in aquatic environments is usually primarily based on uptake and assimilation of nitrate or ammonium. In many cases, both ammonium and nitrate are present, but have different ambient concentrations and turnover rates. Molecular approaches provide a way to identify microorganisms that have the potential to assimilate nitrate and that are expressing the nitrate assimilation apparatus. Relatively few assimilatory nitrate reductase (ANR) genes have previously been sequenced. Primers were designed to conserved regions within the ANR gene, and used to amplify ANR from representative bacterial and cyanobacterial cultures (including Vibrio, Trichodesmium, Clostridium, Plectonema, and Pseudomonas), and natural marine microbial assemblages. Phylogenetic analysis of the sequences obtained showed that bacterial and cyanobacterial ANR genes could be distinguished, indicating that genes from uncultivated microorganisms could be classified. NR was amplified from DNA extracted from samples collected from the Pacific Ocean (HOT) and the South Atlantic Bight (oligotrophic and highly productive waters). Two of the Pacific sequences were found to cluster among the cyanobacteria, while a third clustered with the sequence from Clostridium oceanicum. Results indicate that nitrate reductase genes can be amplified from natural communities, providing a new tool for characterizing nitrate assimilation capacity in the environment.
 
Day: Tuesday, Feb. 2
Time: Poster
Location: Sweeney Center
 
Code: SS40TU0467S