细菌殖民因素控制肠道微生物群的特异性和稳定性
S Melanie Lee1, Gregory P Donaldson, Zbigniew Mikulski
1Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA.
Nature
|August 20, 2013
概括
开始殖民因子 (CCF) 系统允许 Bacteroides 细菌专门殖民哺乳动物肠道. 这个系统有助于细菌附着在结肠表面,并保持长期的殖民,即使在干扰后.
科学领域:
- 微生物学 微生物学
- 胃肠病学 胃肠病学
- 宿主-微生物相互作用
背景情况:
- 哺乳动物的肠道微生物对健康至关重要,其中Bacteroides是占主导地位的属.
- 生物共生细菌稳定殖民胃肠道的机制尚不清楚.
- 在肠道微生物群中观察到特定物种的殖民抗性.
研究的目的:
- 阐明使肠道 Bacteroides 种类能够稳定定殖民的分子机制.
- 确定负责哺乳动物肠道中特定物种,和殖民的细菌因素.
主要方法:
- 没有细菌的小鼠被用于单关联实验,以研究殖民抵抗力.
- 在体内进行基因选,以确定细菌殖民因素.
- 已识别的基因的删除突变被创建并测试了小鼠的殖民缺陷.
- 微生物生物地理在小鼠结肠内使用显微镜可视化.
主要成果:
- 一个新的类型的多糖利用位点,称为开始殖民因子 (ccf),在肠道中被发现并保存.
- 在 Bacteroides fragilis 中删除 ccf 基因损害了小鼠的殖民,并减少了水平传播.
- 具有完整ccf基因的B. fragilis穿透了结肠粘液并居住在密码通道中,而ccf突变体显示出有缺陷的密码关联.
- 在Citrobacter rodentium感染或抗生素治疗等干扰后,CCF系统对于B. fragilis殖民恢复至关重要.
结论:
- 肠道细菌类已经与宿主进化了特定物种的相互作用,通过CCF系统进行调解,以实现稳定和有弹性的肠道殖民.
- CCF系统代表了一种新的分子机制,使细菌能够利用特定的宿主,如结肠密室,进行长期的共生.
- 结肠洞穴作为维持细菌种群的水库,促进了弹性和长期殖民.
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