The strict anaerobe Bacteroides fragilis grows in and benefits from nanomolar concentrations of oxygen
The strict anaerobe Bacteroides fragilis grows in and benefits from nanomolar concentrations of oxygen
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DOI：
10.1038/nature02285
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发表时间：
2004-01-29
期刊：
影响因子：
64.8
通讯作者：
Malamy, MH
中科院分区：
文献类型：
--
作者：
Baughn, AD;Malamy, MH
严格厌氧菌不能在大于5 μ M溶解氧的存在下生长（1）。尽管有这种生长抑制，但真细菌的拟杆菌类的许多严格厌氧菌可以在含氧环境中存活，直到O-2（P-O 2）的分压充分降低。例如，牙周病原体牙龈卟啉单胞菌（Porphyromonas gingivalis）和坦纳氏菌（Tannerella lasthensis）定殖于哺乳动物的龈下菌斑，而几种其他拟杆菌属物种定殖于动物的胃肠道。有人认为，通过兼性厌氧菌在这些位点的预先定殖对于减少P-O2和随后通过严格厌氧菌的定殖是必不可少的（2）。然而，该模型与脆弱拟杆菌可在无兼性厌氧菌的情况下定殖结肠的观察结果不一致（3）。因此，这种严格的厌氧菌可能在减少环境中的P-O2中发挥作用。虽然一些严格厌氧的细菌可以通过完整的膜电子传递系统消耗氧气，但该系统的生理作用尚未在这些生物体中建立。这里我们证明了B. fragilis编码细胞色素bd氧化酶，其对于O-2消耗是必需的，并且在某些条件下是在纳摩尔浓度的O-2存在下刺激生长所需的。此外，我们的数据表明，这种性质是保守的，在许多其他生物已被描述为严格的厌氧菌。
Strict anaerobes cannot grow in the presence of greater than 5 muM dissolved oxygen(1). Despite this growth inhibition, many strict anaerobes of the Bacteroides class of eubacteria can survive in oxygenated environments until the partial pressure of O-2 (P-O2) is sufficiently reduced. For example, the periodontal pathogens Porphyromonas gingivalis and Tannerella forsythensis colonize subgingival plaques of mammals, whereas several other Bacteroides species colonize the gastrointestinal tract of animals. It has been suggested that pre-colonization of these sites by facultative anaerobes is essential for reduction of the P-O2 and subsequent colonization by strict anaerobes(2). However, this model is inconsistent with the observation that Bacteroides fragilis can colonize the colon in the absence of facultative anaerobes(3). Thus, this strict anaerobe may have a role in reduction of the environmental P-O2. Although some strictly anaerobic bacteria can consume oxygen through an integral membrane electron transport system(4), the physiological role of this system has not been established in these organisms. Here we demonstrate that B. fragilis encodes a cytochrome bd oxidase that is essential for O-2 consumption and is required, under some conditions, for the stimulation of growth in the presence of nanomolar concentrations of O-2. Furthermore, our data suggest that this property is conserved in many other organisms that have been described as strict anaerobes.