Kaur Harrisham, Das Chandrani, Mande Sharmila S
Bio-Sciences R&D Division, TCS Research, Tata Consultancy Services Ltd., Pune, India.
Front Microbiol. 2017 Nov 7;8:2166. doi: 10.3389/fmicb.2017.02166. eCollection 2017.
Fermentation of undigested proteins in human gastrointestinal tract (gut) by the resident microbiota, a process called bacterial putrefaction, can sometimes disrupt the gut homeostasis. In this process, essential amino acids (e.g., histidine, tryptophan, etc.) that are required by the host may be utilized by the gut microbes. In addition, some of the products of putrefaction, like ammonia, putrescine, cresol, indole, phenol, etc., have been implicated in the disease pathogenesis of colorectal cancer (CRC). We have investigated bacterial putrefaction pathways that are known to be associated with such metabolites. Results of the comprehensive analysis of the selected putrefaction pathways across bacterial genomes revealed presence of these pathways in limited bacterial groups. Majority of these bacteria are commonly found in human gut. These include , etc. Interestingly, while pathogens utilize almost all the analyzed pathways, commensals prefer putrescine and HS production pathways for metabolizing the undigested proteins. Further, comparison of the putrefaction pathways in the gut microbiomes of healthy, carcinoma and adenoma datasets indicate higher abundances of putrefying bacteria in the carcinoma stage of CRC. The insights obtained from the present study indicate utilization of possible microbiome-based therapies to minimize the adverse effects of gut microbiome in enteric diseases.
人体胃肠道中的常驻微生物群对未消化蛋白质的发酵过程，即所谓的细菌腐败作用，有时会破坏肠道内环境稳定。在这个过程中，宿主所需的必需氨基酸（如组氨酸、色氨酸等）可能会被肠道微生物利用。此外，一些腐败产物，如氨、腐胺、甲酚、吲哚、苯酚等，与结直肠癌（CRC）的疾病发病机制有关。我们研究了已知与这些代谢产物相关的细菌腐败途径。对细菌基因组中选定腐败途径的综合分析结果显示，这些途径仅存在于有限的细菌类群中。这些细菌大多常见于人体肠道。其中包括等等。有趣的是，虽然病原体几乎利用了所有分析过的途径，但共生菌更倾向于利用腐胺和硫化氢产生途径来代谢未消化的蛋白质。此外，对健康、癌组织和腺瘤数据集的肠道微生物群中腐败途径的比较表明，在结直肠癌的癌组织阶段，腐败细菌的丰度更高。本研究获得的见解表明，可利用基于微生物群的疗法来尽量减少肠道微生物群在肠道疾病中的不良影响。
