Analysis Of Mother-Infant Intestinal Microbial Diversity And Function Gene Based On Single Cell Amplification Technique

Considering that intestinal bacteria can have long-term effects on host physiology and health.Pregnant women and newborns,as a special group,have the characteristics of low immunity and incomplete intestinal function.In order to analyze the information of healthy maternal and infants intestinal bacterial diversity and gene function fully or understand the metabolic characteristics and potential of microorganism,the technique combination of single cell amplification and macrogenomics are used in this paper.The bacterial community structure and gene functional composition of 48 suspensions of bacterial cells of fecal samples from 3 pairs of mothers and infants were analyzed.To explore the correlation between short chain fatty acids and functional genes related to the biosynthesis of human milk oligosaccharides and intestinal bacteria,because of the key role of short chain fatty acids in energy intaking and immune regulationing during pregnancy or the key role of human milk oligosaccharides in energy intaking and the health regulation for newborn infants.Both maternal and infant intestinal bacteria include 701 genera and 1285 species which far more than the reported classification abundance that the composition of the intestinal flora of healthy adults of 1,000 to 1,150 bacterial species and 160 bacterial species among individuals.The detection limit is 10-7 for relative abundance,which demonstrates the technical superiority of the method of single cell amplification combined with metagenomics when used to obtain information on the diversity of intestinal bacteria comprehensively.Korarchaeum and Cenarchaeum were not included in the mother samples and Symbiobacterium and Nasuia were not included in the infant samples.The number is more than the existing classification estimate that 135 genera were shared between mother and infant intestinal.The maternal intestinal bacteria are dominated by healthy intestinal bacteria such as Blautia?Eubacterium?Anaerostipes?Rosebria and so on,with good clustering among samples.There are 16 core genera in which the relative abundance of the mother samples exceeds 1%,accounting for 76.10%of the total microbial content.The intestinal flora of cesarean section infants are mainly dominated by Bacteria from the skin or environment such as Propionihacteriunu Delftia?Acinetobacter?Capnocytophaga and so on,with a total of 81.98%.The intestinal flora of the naturally born infant are dominated by healthy intestinal bacteria such as Roseburia?Eubacterium?Faecalibacterium?Coprococcus and so on,with a total of 65.86%.In addition,these results suggest that the abundance and the colonization rate of intestinal bacteria were underestimated significantly in a short period of time after birth in existed studies.The analysis of low-abundance species found that the abundance of 440 species were as low as 10-6 and 67 species as low as 10-7 in the mother samples.Most of these strains have not been reported before,but they were steadily distributed in all samples including newborn infants,suggesting that a wide distribution of low-abundance species in the intestine.Among them,Cellvibrio gilvus?Cellulomonas fimi?Cellulomonas flavigena were first discovered in the intestinal mesophilic environment,which have been proved to be highly active in the degradation of crystalline cellulose.It suggests that there are diverse cellulose decomposition mechanisms?abundant cellulose degradation strains and functional gene resources in the intestinal environment.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 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.Correlation analysis about functional genes of human milk oligosaccharides metabolism and bacteria shows the existing intact metabolic pathways by intestinal bacterias in newborn infants,most of them are positively correlated with the core microflora of preterm infants and negatively correlated with the core microflora of caesarean infants.