基于单细胞扩增技术的细菌多样性及功能基因分析

Analysis of Intestinal Microbial Diversity and Function Gene Based on Single Cell Amplification Technique

本研究采用单细胞扩增技术与宏基因组学相结合策略以期全面了解产妇肠道细菌多样性及基因功能信息,为深入理解微生物代谢特性及潜能提供理论基础。对来自5位健康产妇共计40份粪便样本稀释液进行细菌群落结构及基因功能组成分析,并鉴于短链脂肪酸(short-chain fatty acids,SCFAs)在孕期能量及免疫调节中的关键作用,进一步探讨其生物合成相关功能基因分布及与核心菌群相关性。共享核心菌门4个,依次为厚壁菌门(0.88%)、拟杆菌门(0.07%)、变形菌门(0.02%)和广古菌门(0.02%),其中厚壁菌门与拟杆菌门(17.59∶1)较普通健康成人(1∶1)差异显著;共享核心菌属25个,占样品微生物总量的77.99%,样本间差异显著。基因功能涉及转运因子、DNA修复、重组蛋白、核糖体等306个功能大类;相关性热图显示肠道细菌为难消化多糖转化SCFAs提供完整遗传代谢途径,其中拟杆菌门和厚壁菌门相关菌属分别在多糖降解和SCFAs生成中表现各自优势。细菌群落结构具显著妊娠特症,且属水平表现较大宿主特异性;其中SCFAs途径菌间代谢偏好差异及互补特性提示肠道细菌可能存在复杂的菌间互养cross-feeding网络,菌间合作为营养及能量高效摄取、增强孕产期能量储备提供可能。

In order to analyze the information of maternal intestinal bacterial diversity and gene function fully and understand the metabolic characteristics or potential of microorganism,the technique combination of single cell amplification and macrogenomics are used in this paper.Total 40 fecal diluent samples belonging to 5 healthy parturients are used for analysis of bacterial community structure and gene function.And given the key role of short-chain fatty acids in energy and immune regulation during pregnancy,the diversity of their biosynthesisrelated functional genes and their correlation with core flora were further investigated.Total 4 core phyla shared in fecal samples,are firmicutes(0.88%),bacteroidetes(0.07%),proteomycotes(0.02%)and archaea(0.02%)respectively.The ratio of firmicutes to bacteroidetes(17.59∶1)is different from that of normal healthy adults(1∶1),may be parallel to the increased energy intake duringpregnancy;Total 25 core generas are accounting for 77.99%of the total microbial biomass of all samples,showing a large sample specificity.Gene function involves 306 functional groups,including transport factor,DNA repair,recombinant protein,ribosome,with no significant difference among samples.Analysis of functional genes related to polysaccharide metabolism and short-chain fatty acid production shows that multiple strains can provide additional genetic metabolic pathways for the host.Among them,bacteroidetes and firmicutes shows their advantages in polysaccharide degradation and short-chain fatty acid production respectively,the cooperation between bacterias is beneficial to the uptaking of nutrition and energy efficiently and enhances the reserving of energy during pregnancy.The bacterial community structure has significant gestation characteristics and shows a large host specificity at the genus level.The relevant heatmap shows that intestinal bacteria provide supplementary genetic metabolic pathways for the conversion of indigestible polysaccharide into short-chain fatty acids.The differences in metabolic preferences and complementarity among bacteria may indicate the existence of complex cross-feeding networks among intestinal bacteria.