Response of a strict anaerobe to oxygen: survival strategies in Desulfovibrio gigas.
The biochemical response to oxygen of the strictly anaerobic sulfate-reducing bacterium Desulfovibrio gigas was studied with the goal of elucidating survival strategies in oxic environments. Cultures of D. gigas on medium containing lactate and sulfate were exposed to oxygen (concentration 5-120 micro M). Growth was fully inhibited by oxygen, but the cultures resumed growth as soon as they were shifted back to anoxic conditions. Following 24 h exposure to oxygen the growth rate was as high as 70 % of the growth rates observed before oxygenation. Catalase levels and activity were enhanced by exposure to oxygen whereas superoxide-scavenging and glutathione reductase activities were not affected. The general pattern of cellular proteins as analysed by two-dimensional electrophoresis was altered in the presence of oxygen, the levels of approximately 12 % of the detected proteins being markedly increased. Among the induced proteins, a homologue of a 60 kDa eukaryotic heat-shock protein (Hsp60) was identified by immunoassay analysis. In the absence of external substrates, the steady-state levels of nucleoside triphosphates detected by in vivo (31)P-NMR under saturating concentrations of oxygen were 20 % higher than under anoxic conditions. The higher energy levels developed under oxygen correlated with a lower rate of substrate (glycogen) mobilization, but no experimental evidence for a contribution from oxidative phosphorylation was found. The hypothesis that oxygen interferes with ATP dissipation processes is discussed.
Fareleira
Paula
P
Estação Agronómica Nacional, Instituto Nacional de Investigação Agrária, Quinta do Marquês, 2780-156 Oeiras, Portugal.|Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande, 6 Apartado 127, 2780-156 Oeiras, Portugal.
Santos
Bruno S
BS
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande, 6 Apartado 127, 2780-156 Oeiras, Portugal.
António
Célia
C
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande, 6 Apartado 127, 2780-156 Oeiras, Portugal.
Moradas-Ferreira
Pedro
P
Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150 Porto, Portugal.
LeGall
Jean
J
Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.|Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande, 6 Apartado 127, 2780-156 Oeiras, Portugal.
Xavier
António V
AV
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande, 6 Apartado 127, 2780-156 Oeiras, Portugal.
Santos
Helena
H
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande, 6 Apartado 127, 2780-156 Oeiras, Portugal.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000693:Anaerobiosis; D001426:Bacterial Proteins / Q000096:biosynthesis; D002374:Catalase / Q000378:metabolism; D003901:Desulfovibrio / Q000254:growth & development / Q000378:metabolism*; D004734:Energy Metabolism; D006360:Heat-Shock Proteins / Q000096:biosynthesis; D019344:Lactic Acid / Q000378:metabolism; D010085:Oxidative Phosphorylation; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism*; D019289:Pyruvic Acid / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism
D001426:Bacterial Proteins; D006360:Heat-Shock Proteins; D013431:Sulfates; D019344:Lactic Acid; D019289:Pyruvic Acid; D000255:Adenosine Triphosphate; D002374:Catalase; D010100:Oxygen