Effect Of Probiotic Lactobacillus Casei Zhang On Human Intestinal Flora Based On Transcriptome

Gut microbes have important relationship with host immune,metabolic,nutrition,intestinal disease,and other disease.Many studies have shown that probiotics play important roles in balancing the gut microbiota and regulating the structure of gut microbes.However,only few studies have focused on whether the ingestion of probiotics can modulate the transcription of the host gut microbiota.In this study,we used the Illumina sequence technology to show the influence of infesting Lactobacillus casei on the human gut phylogenic metagenome and metatranscriptome.Fecal samples were collected at three time points during the period of L.casei Zhang ingestion.Metagenomics DNA of the samples were extracted for analyzing changes in the bacterial community at different stages.Meanwhile,high-throughput cDNA sequencing was performed.Metatranscriptomic library was built to analysis the metabolic pathway changes at the gut microbial transcriptomic level after probiotics ingestion.The main findings are as follows:Results of the metagenomics analysis showed that,the effect of L.casei Zhang consumption was far lower than that of the gut microbiota difference between individuals.Although,L.casei Zhang ingestion was able to modulate the structure of intestinal flora.Results of the metatranscriptomics analysis showed no clustering tendency in the L.casei Zhang modulated gene expression levels;however,in most individuals,we observed consistent suppression of gene expression in 14 taxa.COG functional classification analysis of the metatranscriptome dataset showed that 22 functional categories were up-regulated,including Lipid transport and metabolism,Carbohydrate transport and metabolism,Amino acid transport and metabolism,etc.Besides,KEGG pathway analysis found apparent enrichment in genes that mainly involved in the metabolism of vitamins,amino acids,and short-chain fatty acids(e.g.galactose,ascorbate,taurine,and propanoate metabolism).Clustering pattern was shown in the L.casei Zhang metatranscriptomes before and after L.casei Zhang ingestion.Prior to L.casei Zhang ingestion,the transcribed genes were primarily responsible for metabolism of ribosomes,butanoate,and synthesis of other important short-chain fatty acids.After L.casei Zhang ingestion,apparent increases were observed mainly in genes taking part in the metabolism of galactose,fructose,mannose,ascorbate,taurine and hypotaurine,and propanoate.Besides,strongly enriched genes included the ABC transporters and metabolism pathways of multiple amino acids.