Methanobrevibacter and Methanosphaera species represent some of the most prevalent methanogenic archaea in the gastrointestinal tract of animals and humans and play an important role in this environment. The aim of this study was to identify genomic features that are shared or specific for members of each genus with a special emphasis of the analysis on the assimilation of nitrogen and acetate and the utilization of methanol and ethanol for methanogenesis. Here, draft genome sequences of Methanobrevibacter thaueri strain DSM 11995^T, Methanobrevibacter woesei strain DSM 11979^T, and Methanosphaera cuniculi strain 4103^T are reported and compared to those of 16 other Methanobrevibacter and Methanosphaera genomes, including genomes of the 13 currently available types of strains of the two genera. The comparative genome analyses indicate that among other genes, the absence of molybdopterin cofactor biosynthesis is conserved in Methanosphaera species but reveals also that the three species share a core set of more than 300 genes that distinguishes the genus Methanosphaera from the genus Methanobrevibacter. Multilocus sequence analysis shows that the genus Methanobrevibacter can be subdivided into clades, potentially new genera, which may display characteristic specific metabolic features. These features include not only the potential ability of nitrogen fixation and acetate assimilation in a clade comprised of Methanobrevibacter species from the termite gut and Methanobrevibacter arboriphilus strains but also the potential capability to utilize ethanol and methanol in a clade comprising Methanobrevibacter wolinii strain DSM 11976^T, Mbb. sp. AbM4, and Mbb. boviskoreani strain DSM 25824^T.

中文翻译：

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甲烷球菌属和甲烷短杆菌属成员的比较基因组分析揭示了具有特定潜在代谢功能的不同进化枝。

甲烷短杆菌属和甲烷菌属物种代表了动物和人类胃肠道中最普遍的产甲烷古细菌，并且在这种环境中起着重要作用。这项研究的目的是确定每个属成员共有或特定的基因组特征，并特别强调分析氮和乙酸的同化以及利用甲醇和乙醇进行甲烷生成。在这里，拟南芥杆菌DSM 11995 ^T，沃萨氏甲烷杆菌DSM 11979 ^T和库氏甲烷球菌4103 ^T的基因组序列草案据报道，并将其与其他16个甲烷甲烷短杆菌属和甲烷菌属基因组的基因组进行比较，包括两个属的13种当前可用类型的菌株的基因组。对比基因组分析表明，除其他基因外，甲烷球菌属物种中不存在钼蝶呤辅因子生物合成，但也揭示了这三个物种共有一个核心组，包含300多个基因，可将甲烷菌属与甲烷短杆菌属区分开。多基因座序列分析表明，Methanobrevibacter属可以细分为进化枝，可能是新的属，可以表现出特定的新陈代谢特征。这些特征不仅包括在由白蚁肠中的甲烷单歧杆菌属种和树型甲烷单歧杆菌组成的进化枝中，固氮能力和乙酸同化作用的潜在能力，而且还包括在沃森氏蓝细菌菌株DSM 11976 ^T组成的进化枝中利用乙醇和甲醇的潜在能力，Mbb。sp。AbM4和Mbb。boviskoreani菌株DSM 25824 ^Ť。