Molecular characterization of host-specific biofilm formation in a vertebrate gut symbiont.
Molecular characterization of host-specific biofilm formation in a vertebrate gut symbiont.
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DOI：
10.1371/journal.pgen.1004057
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发表时间：
2013
期刊：
影响因子：
4.5
通讯作者：
Walter J
中科院分区：
文献类型：
--
作者：
Frese SA;Mackenzie DA;Peterson DA;Schmaltz R;Fangman T;Zhou Y;Zhang C;Benson AK;Cody LA;Mulholland F;Juge N;Walter J
尽管脊椎动物在其胃肠道中含有细菌群落，其组成是宿主特异性的，但人们对细菌谱系被选择的机制知之甚少。本研究的目的是表征介导脊椎动物肠道共生体罗伊氏乳杆菌宿主特异性的生态过程，并系统地识别所涉及的细菌因素。单相关小鼠实验表明，罗伊氏乳杆菌在小鼠前胃形成上皮生物膜的能力严格依赖于菌株的宿主来源。为了揭示这种宿主特异性生物膜形成的分子基础，我们采用转录组分析和比较基因组学相结合的方法，鉴定了罗伊氏乳杆菌100-23中预计起作用的11个基因。然后，我们确定了这些基因在单相关小鼠体内生物膜形成过程中的表达和重要性。该分析显示，其中6个基因在体内被上调，编码参与上皮粘附、特化蛋白质运输、细胞聚集、环境感知和细胞裂解的蛋白质的基因有助于生物膜的形成。具有专用运输系统（SecA2-SecY2途径）的富含丝氨酸的表面粘附素失活完全取消了生物膜的形成，表明初始粘附是生物膜形成中最重要的步骤，可能赋予宿主特异性。综上所述，本研究确定了脊椎动物肠道中细菌共生体的上皮选择既特异性又高效，导致生物膜仅由共同进化的菌株形成，并允许深入了解这一过程的细菌效应物。在脊椎动物胃肠道中发现的细菌群落非常稳定，并且具有宿主特异性。然而，促进微生物共生体选择和有害细菌排除的生态和分子过程尚不清楚。在这里，我们探讨了肠道共生体罗伊氏乳杆菌特定菌株的定植和生物膜形成的机制。当先前无菌的小鼠被单个罗伊氏乳杆菌菌株定植时，只有来自啮齿动物的菌株在前胃上皮上形成生物膜。基因组学、蛋白质组学和分子分析提供了对宿主特异性分子过程的详细研究，例如有助于定植和生物膜形成的粘附。我们的研究结果表明，细菌肠道居民的上皮选择具有很高的保真度，甚至可以区分同一物种的菌株，从而加强了脊椎动物与其微生物共生体之间的某些关系是高度共同进化和排他性的概念。
Although vertebrates harbor bacterial communities in their gastrointestinal tract whose composition is host-specific, little is known about the mechanisms by which bacterial lineages become selected. The goal of this study was to characterize the ecological processes that mediate host-specificity of the vertebrate gut symbiont Lactobacillus reuteri, and to systematically identify the bacterial factors that are involved. Experiments with monoassociated mice revealed that the ability of L. reuteri to form epithelial biofilms in the mouse forestomach is strictly dependent on the strain's host origin. To unravel the molecular basis for this host-specific biofilm formation, we applied a combination of transcriptome analysis and comparative genomics and identified eleven genes of L. reuteri 100-23 that were predicted to play a role. We then determined expression and importance of these genes during in vivo biofilm formation in monoassociated mice. This analysis revealed that six of the genes were upregulated in vivo, and that genes encoding for proteins involved in epithelial adherence, specialized protein transport, cell aggregation, environmental sensing, and cell lysis contributed to biofilm formation. Inactivation of a serine-rich surface adhesin with a devoted transport system (the SecA2-SecY2 pathway) completely abrogated biofilm formation, indicating that initial adhesion represented the most significant step in biofilm formation, likely conferring host specificity. In summary, this study established that the epithelial selection of bacterial symbionts in the vertebrate gut can be both specific and highly efficient, resulting in biofilms that are exclusively formed by the coevolved strains, and it allowed insight into the bacterial effectors of this process. The bacterial communities found in the vertebrate gastrointestinal tract are remarkably stable and host-specific. However, the ecological and molecular processes that facilitate the selection of microbial symbionts and the exclusion of detrimental bacteria are not well understood. Here, we explore the mechanisms that underlie colonization and biofilm formation in specific strains of the gut symbiont Lactobacillus reuteri. When previously germ-free mice are colonized by individual strains of L. reuteri, only strains originating from rodents formed biofilms on the forestomach epithelium. Genomic, proteomic, and molecular analysis provide a detailed look into the host-specific molecular processes, such as adhesion, that contribute to colonization and biofilm formation. Our findings demonstrate high fidelity in the epithelial selection of a bacterial gut inhabitant, which can differentiate even between strains of the same species, strengthening the notion that some relationships between vertebrates and their microbial symbionts are highly coevolved and exclusive.
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影响因子：
12.3
作者：
Gentleman RC;Carey VJ;Bates DM;Bolstad B;Dettling M;Dudoit S;Ellis B;Gautier L;Ge Y;Gentry J;Hornik K;Hothorn T;Huber W;Iacus S;Irizarry R;Leisch F;Li C;Maechler M;Rossini AJ;Sawitzki G;Smith C;Smyth G;Tierney L;Yang JY;Zhang J
通讯作者：
Zhang J
影响因子：
4.4
作者：
FULLER, R;BARROW, PA;BROOKER, BE
通讯作者：
BROOKER, BE
影响因子：
5.8
作者：
Feng, Jianxing;Meyer, Clifford A.;Zhang, Yong
通讯作者：
Zhang, Yong
影响因子：
56.9
作者：
Ley, Ruth E.;Hamady, Micah;Gordon, Jeffrey I.
通讯作者：
Gordon, Jeffrey I.
影响因子：
12.3
作者：
Langmead B;Trapnell C;Pop M;Salzberg SL
通讯作者：
Salzberg SL