title: Morphogenesis of the membrane-bound electron-transport system in sporulating Bacillus megaterium KM.
abstract: The properties of electron transport systems present in soluble and particulate fractions of spores of Bacillus megaterium KM?HAVE BEEN COMPARED WIth those of similar fractions prepared from exponential-phase vegetative cells of this organism. The timing and localization of modifications of the electron transport system occurring during sporulation have been investigated by using a system for separating forespores from mother cells at all stages during development [8]. Spore membranes contained cytochromes a + a3, and o at lower concentrations than in vegetative membranes, and in addition cytochrome c, which was not found in exponential-phase vegetative membranes. An NADH oxidase activity of similar specific activity was found in both spore and vegetative membranes but DL-glycerol 3-phosphate and L-malate oxidase activities were found only in vegetative membranes. A soluble NADH oxidase of low specific activity was found in spores and vegetative cells which probably involves a flavoprotein reaction with oxygen because the activity was stimulated by FAD or FMN and difference spectra of concentrated soluble fractions showed spectra typical of a flavoprotein. Particulate NADH oxidase was sensitive to all classical inhibitors of electron transport tested whereas soluble NADH oxidase was insensitive to many of these inhibitors. Cytochrome c was formed between stage I and II of sporulation and this coincided with a five-fold increase in NADH-cytochrome c reductase activity. Forespore membranes had lower contents of cytochromes than sporangial cell membranes but similar levels of NADH and L-malate oxidases; DL-glycerol 3-phosphate oxidase activity could not be detected in either membranes by stage III of sporulation. This characterization of spore electron transport systems provides a basis for suggestions concerning initial metabolic events during spore germination and the effect of a number of germination inhibitors.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D001410:Bacillus megaterium / Q000378:metabolism*; D002455:Cell Division; D002462:Cell Membrane / Q000378:metabolism*; D003580:Cytochromes / Q000378:metabolism; D004579:Electron Transport; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D010101:Oxygen Consumption; D013053:Spectrophotometry; D013171:Spores, Bacterial / Q000378:metabolism; D013997:Time Factors
chemical_list: D003580:Cytochromes; D005993:Glycerolphosphate Dehydrogenase; D008291:Malate Dehydrogenase; D009247:NADH, NADPH Oxidoreductases; D009251:NADPH-Ferrihemoprotein Reductase; D000251:Adenosine Triphosphatases