人工饲养恒河猴幼猴不同肠段微生物宏基因组学研究

Metagenomic analysis on microbiota in different parts of gut tracts of artificially reared baby Rhesus macaques

目的以恒河猴幼猴为模型,采用16S rRNA宏基因组方法探讨十二指肠、盲肠、直肠的菌群组成。方法收集4例健康幼猴十二指肠、盲肠、直肠样本,提取细菌总DNA,采用新一代高通量测序技术对16S rRNA基因的V3-V4高变区测序,分析比较菌群结构及多样性。结果 (1)门水平各肠段微生物优势菌群主要为硬壁菌门、变形菌门及拟杆菌门,在各肠段中的占比总和超过88%;(2)属水平,十二指肠中以芽胞杆菌属等为优势菌属,盲肠中以螺杆菌属、颤杆菌属、孢杆菌属等为优势菌属,直肠中以乳酸菌属、链球菌属、颤杆菌属等为优势菌属;(3)各肠段微生物功能差异较大,十二指肠主要承担营养物质的消化吸收,盲肠主要承担细胞及遗传物质的合成,直肠主要承担调节机体免疫力、抗感染等功能。结论各肠段菌群组成差异较大;各肠段细菌功能差异较大,且与其生理功能有一定关联;在肠道菌群研究中,应充分考虑粪便样品微生物的组成是否能够完全代表肠道微生物的组成。

Objective To explore the composition of microflora in the duodenum,cecum and rectum of healthy baby Rhesus macaques.Methods Samples of duodenum,cecum and rectum were collected from 4 Rhesus macaques at age of 1.5 years.The total bacterial DNAs were extracted,and the region V3-V4 of 16S rRNA gene was sequenced by using Illumina MiSeq.The gut bacterial communities were analyzed.Results（1）On the phylum level,the dominant microbial communities in each intestinal segment were Firmicutes,Proteobacteria and Bacteroidetes,accounting for more than 88% of the total community.（2）On the genus level,the dominant microbial community was Bacilli in duodenum;The dominant microbial communities were Helicobacter,Oscillibacter and Sporobacter in cecum,while Lactobacilli,Streptococci and Oscillibacterin rectum.（3）There were significant differences in the function of bacteria in different intestinal segments.The duodenum was mainly responsible for digestion and absorption of nutrients,the cecum was mainly responsible for synthesis of cellular and genetic material,while the rectum was mainly responsible for regulating immunity and resisting infections.Conclusion There are significant differences in the composition of microflora and in the function of bacteria in different intestinal segments,which is related to the physiological function.In the study of intestinal flora,whether the composition of fecal microorganisms can fully represent the composition of intestinal microorganisms should be taken into consideration.