The Glycobiome of the Rumen Bacterium Butyrivibrio proteoclasticus B316T Highlights Adaptation to a Polysaccharide-Rich Environment
The Glycobiome of the Rumen Bacterium Butyrivibrio proteoclasticus B316T Highlights Adaptation to a Polysaccharide-Rich Environment
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DOI：
10.1371/journal.pone.0011942
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发表时间：
2010-08-03
期刊：
影响因子：
3.7
通讯作者：
Attwood, Graeme T.
中科院分区：
文献类型：
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作者：
Kelly, William J.;Leahy, Sinead C.;Attwood, Graeme T.
确定瘤胃微生物及其酶在植物多糖分解中的作用是理解反刍动物消化和最大化生产力的基础。溶蛋白丁酸弧菌B316（T）是一种革兰氏阳性的丁酸盐形成菌，在植物多糖降解中起关键作用。4.4Mb的基因组由4个复制子组成;一个染色体，一个染色质和两个大质粒。染色质是所有细菌中报道的最小的，也是第一个从厚壁菌门中鉴定出来的。B316将其基因组的很大一部分用于复杂多糖的分解和重组，并且与其他测序细菌相比具有高度发达的糖生物组。一系列多糖降解酶的分泌，其引发果胶、淀粉和木聚糖的分解，一种对植物蛋白具有活性的枯草杆菌蛋白酶家族蛋白酶，以及分解寡糖的多种细胞内酶，构成了该生物体的降解能力。基因组的一个突出特征是存在多个预测参与多糖生物合成的基因簇。代谢重建揭示了一个可识别的基因烯醇化酶，糖酵解途径的保守酶的情况下。据我们所知，这是第一个缺乏烯醇化酶的生物体的报告。我们对B316基因组的分析显示了一种生物如何有助于快速分解瘤胃中植物材料的多生物复合体。可以得出结论，B316，和类似的生物具有广泛的多糖降解能力，是非常适合的早期殖民者和降解植物多糖在瘤胃环境中。
Determining the role of rumen microbes and their enzymes in plant polysaccharide breakdown is fundamental to understanding digestion and maximising productivity in ruminant animals. Butyrivibrio proteoclasticus B316(T) is a Gram-positive, butyrate-forming rumen bacterium with a key role in plant polysaccharide degradation. The 4.4Mb genome consists of 4 replicons; a chromosome, a chromid and two megaplasmids. The chromid is the smallest reported for all bacteria, and the first identified from the phylum Firmicutes. B316 devotes a large proportion of its genome to the breakdown and reassembly of complex polysaccharides and has a highly developed glycobiome when compared to other sequenced bacteria. The secretion of a range of polysaccharide-degrading enzymes which initiate the breakdown of pectin, starch and xylan, a subtilisin family protease active against plant proteins, and diverse intracellular enzymes to break down oligosaccharides constitute the degradative capability of this organism. A prominent feature of the genome is the presence of multiple gene clusters predicted to be involved in polysaccharide biosynthesis. Metabolic reconstruction reveals the absence of an identifiable gene for enolase, a conserved enzyme of the glycolytic pathway. To our knowledge this is the first report of an organism lacking an enolase. Our analysis of the B316 genome shows how one organism can contribute to the multi-organism complex that rapidly breaks down plant material in the rumen. It can be concluded that B316, and similar organisms with broad polysaccharide-degrading capability, are well suited to being early colonizers and degraders of plant polysaccharides in the rumen environment.