title: Anaerobic growth of a "strict aerobe" (Bacillus subtilis).
abstract: There was a long-held belief that the gram-positive soil bacterium Bacillus subtilis is a strict aerobe. But recent studies have shown that B. subtilis will grow anaerobically, either by using nitrate or nitrite as a terminal electron acceptor, or by fermentation. How B. subtilis alters its metabolic activity according to the availability of oxygen and alternative electron acceptors is but one focus of study. A two-component signal transduction system composed of a sensor kinase, ResE, and a response regulator, ResD, occupies an early stage in the regulatory pathway governing anaerobic respiration. One of the essential roles of ResD and ResE in anaerobic gene regulation is induction of fnr transcription upon oxygen limitation. FNR is a transcriptional activator for anaerobically induced genes, including those for respiratory nitrate reductase, narGHJI.B. subtilis has two distinct nitrate reductases, one for the assimilation of nitrate nitrogen and the other for nitrate respiration. In contrast, one nitrite reductase functions both in nitrite nitrogen assimilation and nitrite respiration. Unlike many anaerobes, which use pyruvate formate lyase, B. subtilis can carry out fermentation in the absence of external electron acceptors wherein pyruvate dehydrogenase is utilized to metabolize pyruvate.
authors.affiliation: Department of Biochemistry and Molecular Biology, Louisiana State University Medical Center, Shreveport 71130-3932, USA. mnakan@lsumc.edu
authors.forename: M M
authors.initials: MM
authors.lastname: Nakano
authors.forename: P
authors.initials: P
authors.lastname: Zuber
mesh_terms: D000693:Anaerobiosis; D001412:Bacillus subtilis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002952:Citric Acid Cycle; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D005285:Fermentation / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics; D000071677:Histidine Kinase; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D011773:Pyruvates / Q000378:metabolism; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D009566:Nitrates; D009573:Nitrites; D011773:Pyruvates; C100386:ResD protein, Bacillus subtilis; D015534:Trans-Activators; D014157:Transcription Factors; D009565:Nitrate Reductases; D050901:Nitrate Reductase; D011494:Protein Kinases; D000071677:Histidine Kinase