SS2.06 Microbial Diversity in Time and Space
Date: Tuesday, June 11, 2002
Location: Poster Session - VCC
 
ArcherCM, Savannah State University/ Skidaway Institute of Oceanography, Savannah, USA, monique_17@hotmail.com
Booth, M, G, Savannah State University/ Skidaway Institute of Oceanography, Savannah, USA, booth@skio.peachnet.edu
Allen, A, E, University of Georgia/ Skidaway Institute of Oceanography, Savannah, USA, aallen@skio.peachnet.edu
Frischer, M, E, Skidaway Institute of Oceanography, Savannah, USA, frischer@skio.peachnet.edu
Gilligan, M, G, Savannah State University, Savannah, USA, gillganm@savstate.peachnet.edu
Verity, P, G, Skidaway Institute of Oceanography, Savannah, USA, peter@skio.peachnet.edu
 
ANALYSIS OF ASSIMILATORY NITRATE REDUCTASE GENE EXPRESSION IN HETEROTROPHIC BACTERIA BY METHOD DEVELOPMENT OF RT-PCR
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Inorganic nitrogen, NO3 and NH4 are considered to be primary nutrients limiting phytoplankton and bacteria productivity in marine environments, respectively. Recently, using molecular techniques targeted to the assimilatory nitrate reductase gene (nasA) in heterotrophic bacteria, we demonstrated that many marine bacteria also have the capacity to utilize nitrate and implying that phytoplankton and bacteria compete for NO3 in nature. In this study a RT-PCR method was developed to study the expression regulation by NH4 and NO3. Studies were conducted using four marine bacteria isolates. Expression of nasA was induced by NO3 in all strains. However, NH4 did not suppress nasA expression in all strains indicating that previously described ammonium suppression of nitrate uptake in bacteria may not be the case in diverse natural marine bacterioplankton communities. The long-term goal of these studies is to determine the signals and processes that regulate nitrate assimilation by heterotrophic bacteria.