Wilkinson B J, Ellar D J
Eur J Biochem. 1975 Jun 16;55(1):131-9. doi: 10.1111/j.1432-1033.1975.tb02145.x.
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.
已将巨大芽孢杆菌KM孢子的可溶性和颗粒性组分中存在的电子传递系统的特性，与从该生物体指数生长期营养细胞制备的类似组分的特性进行了比较。利用一种在发育的所有阶段将前芽孢与母细胞分离的系统[8]，研究了芽孢形成过程中发生的电子传递系统修饰的时间和定位。芽孢膜中细胞色素a + a3和o的浓度低于营养膜，此外还含有细胞色素c，而在指数生长期的营养膜中未发现细胞色素c。在芽孢膜和营养膜中发现了具有相似比活性的NADH氧化酶活性，但仅在营养膜中发现了DL-甘油3-磷酸和L-苹果酸氧化酶活性。在芽孢和营养细胞中发现了一种低比活性的可溶性NADH氧化酶，其可能涉及一种与氧气的黄素蛋白反应，因为该活性受到FAD或FMN的刺激，并且浓缩可溶性组分的差光谱显示出黄素蛋白的典型光谱。颗粒性NADH氧化酶对所测试的所有经典电子传递抑制剂敏感，而可溶性NADH氧化酶对许多这些抑制剂不敏感。细胞色素c在芽孢形成的I期和II期之间形成，并与NADH-细胞色素c还原酶活性增加五倍相吻合。前芽孢膜中的细胞色素含量低于芽孢囊细胞膜，但NADH和L-苹果酸氧化酶水平相似；到芽孢形成的III期时，在这两种膜中均未检测到DL-甘油3-磷酸氧化酶活性。芽孢电子传递系统的这种特征为有关芽孢萌发期间的初始代谢事件以及多种萌发抑制剂的作用的建议提供了基础。
