title: Energy conservation in Bacillus megaterium.
abstract: 1. The respiratory chain energy conservation systems of Bacillus megaterium strains D440 and M have been investigated following growth in batch and continuous culture. Respiratory membranes from these strains contained cytochromes b, aa3, o and b, c, a, o, respecitvely; both readily oxidised NADH but neither showed any pyridine nucleotide transhydrogenase activity. 2. Whole cells of both strains exhibited endogenous leads to H+/O ratios of approximately 4; when loaded with specific substrates the resultant leads to H+/O ratios indicated that proton translocating loops 1 and 2 were present in strain D440 and that loops 2 and 3 were present in strain M. 3. In situ respiratory activities were measured as a function of dilution rate during growth in continuous culture. True molar growth yields with respect to oxygen (Y02) of approximately 50 g cells-mole oxygen-1 were obtained for most of the nutrient limitations employed. Average values for YATP of 12.7 and 10.8 g cells-mole ATP equivalent-1 were subsequently calculated for strains D440 and M respectively. 4. Energy requirements for maintenance purposes were low in energy-limited cultures but were substantially increased when growth was limited by nitrogen source (NH+/4). Under the latter conditions there is probably a partial uncoupling of energy-conserving and energy-utilising processes leading to energy wastage.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000332:Aerobiosis; D001410:Bacillus megaterium / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D003579:Cytochrome Reductases / Q000378:metabolism; D003580:Cytochromes / Q000378:metabolism; D004579:Electron Transport; D004734:Energy Metabolism; D005990:Glycerol / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D011522:Protons; D000644:Quaternary Ammonium Compounds / Q000378:metabolism
chemical_list: D003580:Cytochromes; D011522:Protons; D000644:Quaternary Ammonium Compounds; D000255:Adenosine Triphosphate; D009247:NADH, NADPH Oxidoreductases; D003579:Cytochrome Reductases; D005990:Glycerol