Rosenfeld Eric, Duport Catherine, Zigha Assia, Schmitt Philippe
Laboraatoire de Biotechnologies et Chimie Bio-organique FRE 2766 CNRS, Bâtiment Marie-Curie, Pôle Sciences et Technologies, Université de La Rochelle, 17042 La Rochelle cedex 1, France.
Can J Microbiol. 2005 Feb;51(2):149-58. doi: 10.1139/w04-132.
The Gram-positive bacterium Bacillus cereus is a facultative anaerobe that is still poorly characterized metabolically. In this study, the aerobic vegetative growth and anaerobic vegetative growth of the food-borne pathogen B. cereus F4430/73 strain were compared with those of the genome-sequenced ATCC14579 strain using glucose and glycerol as fermentative and nonfermentative carbon sources, respectively. Uncontrolled batch cultures on several defined media showed that B. cereus strains had high amino acid or pyruvate requirements for anaerobic fermentative growth. In addition, growth performance was considerably improved by maintaining the pH of the culture medium near neutrality. Spectra of fermentation by-products were typically (per mole of glucose) 0.2-0.4 acetate, 1.1-1.4 L-lactate, 0.3-0.4 formate, and 0.05-0.2 ethanol with only traces of succinate, pyruvate, and 2,3-butanediol. These spectra were drastically changed in the presence of 20 mmol nitrate x L(-1), which stimulated anaerobic growth. During anaerobic and aerobic respiration, the persistent production of acetate and other by-products indicated overflow metabolisms. This was especially true in glucose-grown cells for which respiratory complex III made only a minor contribution to growth. Surprisingly, oxygen uptake rates linked to the cytochrome c and quinol branches of the respiratory chain were maintained at high levels in anaerobic, respiring, or fermenting cells. Growth and metabolic features of B. cereus F4430/73 are discussed using biochemical and genomic data.
革兰氏阳性菌蜡样芽孢杆菌是一种兼性厌氧菌，其代谢特征仍不太清楚。在本研究中，以葡萄糖和甘油分别作为发酵性和非发酵性碳源，比较了食源性病原体蜡样芽孢杆菌F4430/73菌株与基因组已测序的ATCC14579菌株的有氧营养生长和厌氧营养生长情况。在几种确定培养基上进行的无控制分批培养表明，蜡样芽孢杆菌菌株在厌氧发酵生长时对氨基酸或丙酮酸有较高需求。此外，将培养基的pH维持在接近中性可显著提高生长性能。发酵副产物的光谱通常（每摩尔葡萄糖）为0.2 - 0.4乙酸盐、1.1 - 1.4 L-乳酸盐、0.3 - 0.4甲酸盐和0.05 - 0.2乙醇，只有微量的琥珀酸盐、丙酮酸和2,3-丁二醇。在存在20 mmol硝酸盐x L(-1)的情况下，这些光谱发生了剧烈变化，硝酸盐刺激了厌氧生长。在厌氧呼吸和好氧呼吸过程中，乙酸盐和其他副产物的持续产生表明存在溢流代谢。在以葡萄糖为碳源生长的细胞中尤其如此，对于这些细胞，呼吸复合体III对生长的贡献很小。令人惊讶的是，在厌氧、呼吸或发酵的细胞中，与呼吸链的细胞色素c和喹啉分支相关的氧摄取率保持在较高水平。利用生化和基因组数据讨论了蜡样芽孢杆菌F4430/73的生长和代谢特征。
