The lifestyle of the segmented filamentous bacterium: a non-culturable gut-associated immunostimulating microbe inferred by whole-genome sequencing.
The lifestyle of the segmented filamentous bacterium: a non-culturable gut-associated immunostimulating microbe inferred by whole-genome sequencing.
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DOI：
10.1093/dnares/dsr022
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发表时间：
2011-08
期刊：
影响因子：
--
通讯作者：
Hayashi T
中科院分区：
文献类型：
--
作者：
Kuwahara T;Ogura Y;Oshima K;Kurokawa K;Ooka T;Hirakawa H;Itoh T;Nakayama-Imaohji H;Ichimura M;Itoh K;Ishifune C;Maekawa Y;Yasutomo K;Hattori M;Hayashi T
许多微生物栖息在哺乳动物的肠道轨道，并强烈影响宿主的生理；然而，由于微生物群落的高度复杂性和大量不可培养微生物的存在，我们对这种生态系统的理解仍然有限。分节丝状细菌（SFBs）是一种与梭状芽胞杆菌相关的革兰氏阳性细菌，属于这种不可培养的菌群，以其独特的形态和与肠上皮细胞的紧密附着而闻名。最近的研究表明，SFBs在出生后肠道免疫功能成熟，特别是Th17淋巴细胞的诱导中起着至关重要的作用。在这里，我们报道了小鼠SFBs的全基因组序列。该基因组由一条长1 620 005 bp的单圆形染色体组成，缺乏几乎所有氨基酸、维生素/辅助因子和核苷酸的生物合成基因，但却包含了一整套用于产孢/萌发的基因，出乎意料的是，还包含了用于趋化性/鞭毛运动的基因。这些发现表明SFB的三相生活方式，包括两种类型的营养（游泳和外细胞寄生）阶段和休眠（孢子）阶段。此外，SFBs编码四种鞭毛蛋白，其中三种被toll样受体5识别，可以引发先天免疫反应。本研究结果揭示了SFB的不可培养性、生活方式和免疫刺激机制，为SFB的培养和基因操作技术的进一步发展提供了遗传学基础。
Numerous microbes inhabit the mammalian intestinal track and strongly impact host physiology; however, our understanding of this ecosystem remains limited owing to the high complexity of the microbial community and the presence of numerous non-culturable microbes. Segmented filamentous bacteria (SFBs), which are clostridia-related Gram-positive bacteria, are among such non-culturable populations and are well known for their unique morphology and tight attachment to intestinal epithelial cells. Recent studies have revealed that SFBs play crucial roles in the post-natal maturation of gut immune function, especially the induction of Th17 lymphocytes. Here, we report the complete genome sequence of mouse SFBs. The genome, which comprises a single circular chromosome of 1 620 005 bp, lacks genes for the biosynthesis of almost all amino acids, vitamins/cofactors and nucleotides, but contains a full set of genes for sporulation/germination and, unexpectedly, for chemotaxis/flagella-based motility. These findings suggest a triphasic lifestyle of the SFB, which comprises two types of vegetative (swimming and epicellular parasitic) phases and a dormant (spore) phase. Furthermore, SFBs encode four types of flagellin, three of which are recognized by Toll-like receptor 5 and could elicit the innate immune response. Our results reveal the non-culturability, lifestyle and immunostimulation mechanisms of SFBs and provide a genetic basis for the future development of the SFB cultivation and gene-manipulation techniques.
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DOI：
10.1038/nrg2749
发表时间：
2010-03
期刊：
Nature reviews. Genetics
影响因子：
--
作者：
通讯作者：
--
DOI：
10.1073/pnas.89.13.5976
发表时间：
1992-07-01
影响因子：
11.1
作者：
GINOCCHIO, C;PACE, J;GALAN, JE
通讯作者：
GALAN, JE
影响因子：
56.9
作者：
Gill, Steven R.;Pop, Mihai;Nelson, Karen E.
通讯作者：
Nelson, Karen E.
影响因子：
11.2
作者：
Chu, FF;Esworthy, RS;Doroshow, JH
通讯作者：
Doroshow, JH
影响因子：
56.9
作者：
Ciccarelli, FD;Doerks, T;Bork, P
通讯作者：
Bork, P