Phylogenetic distribution of three pathways for propionate production within the human gut microbiota
Phylogenetic distribution of three pathways for propionate production within the human gut microbiota
复制标题
DOI：
10.1038/ismej.2014.14
复制
发表时间：
2014-06-01
期刊：
影响因子：
11
通讯作者：
Louis, Petra
中科院分区：
文献类型：
--
作者：
Reichardt, Nicole;Duncan, Sylvia H.;Louis, Petra
丙酸盐是在人体大肠中通过微生物发酵产生的，可能有助于维持人体健康。我们通过对人类肠道微生物群的基因组和宏基因组分析，并通过设计简并引物组来检测这些途径的诊断基因，研究了细菌用于丙酸形成的三种不同途径的分布。丙烯酸酯途径的简并引物（检测编码乳酰辅酶A脱水酶的lcdA基因）以及宏基因组挖掘表明，该途径仅限于毛螺菌科和阴性菌中的少数人类结肠物种。使用稳定同位素标记证实了猫粪球菌（Lachnospiraceae）中乳酸利用途径的运作。处理岩藻糖和鼠李糖等脱氧糖的丙二醇途径在 Lachnospiraceae 中更为丰富（基于编码丙醛脱氢酶的 pduP 基因），存在于瘤胃球菌的近缘种和 Roseburia inulinivorans 中。然而，来自己糖的丙酸的主要来源被认为是琥珀酸途径，编码甲基丙二酸单酰辅酶A脱羧酶的mmdA基因在拟杆菌和许多阴性菌中的广泛分布表明了这一点。一般来说，从己糖生产丙酸或丁酸的能力存在于不同的物种中，尽管现在已知两种毛螺菌科物种（C. catus和R. inulinivorans）能够在不同的底物上从丁酸生产切换到丙酸生产。更好地了解短链脂肪酸形成的微生物生态学可能有助于人类肠道微生物群调节丙酸盐的形成。
Propionate is produced in the human large intestine by microbial fermentation and may help maintain human health. We have examined the distribution of three different pathways used by bacteria for propionate formation using genomic and metagenomic analysis of the human gut microbiota and by designing degenerate primer sets for the detection of diagnostic genes for these pathways. Degenerate primers for the acrylate pathway (detecting the lcdA gene, encoding lactoyl-CoA dehydratase) together with metagenomic mining revealed that this pathway is restricted to only a few human colonic species within the Lachnospiraceae and Negativicutes. The operation of this pathway for lactate utilisation in Coprococcus catus (Lachnospiraceae) was confirmed using stable isotope labelling. The propanediol pathway that processes deoxy sugars such as fucose and rhamnose was more abundant within the Lachnospiraceae (based on the pduP gene, which encodes propionaldehyde dehydrogenase), occurring in relatives of Ruminococcus obeum and in Roseburia inulinivorans. The dominant source of propionate from hexose sugars, however, was concluded to be the succinate pathway, as indicated by the widespread distribution of the mmdA gene that encodes methylmalonyl-CoA decarboxylase in the Bacteroidetes and in many Negativicutes. In general, the capacity to produce propionate or butyrate from hexose sugars resided in different species, although two species of Lachnospiraceae (C. catus and R. inulinivorans) are now known to be able to switch from butyrate to propionate production on different substrates. A better understanding of the microbial ecology of short-chain fatty acid formation may allow modulation of propionate formation by the human gut microbiota.