Taxonomy Of Healthy Gut Microbial Strain TF01-11~T

The human gut is colonised by a large and complex community of microorganisms ranging from 1013 to 1014 microbial cells,which is equivalent to 10 times the number of human cells.There are in total more than 1000 different species in the gut.Most of the intestinal microbiota species are obligate anaerobes.The most predominant bacterial pop?lation of healthy human gut is made up of phyla Bacteroidetes and Firmicutes.The microbe begin to resident the intestinal tract shortly after birth and develop over the first few years.These gut microbiota play a key role involving nutrition extraction,host metabolic,prevention against pathogens and immune reg?lation.Current evidence also suggests that the gut microbiota can be considered as an environmental factor in development of disease,including obesity,diabetes,inflammatory bowel disease and colorectal cancer.Recent study towards gut microbiota is still base on metagenome sequencing,a kind of culture-independent approach.While,there are a minority of researchers use the culture-dependent strategy for microbiota strain library construction,sdudying the diversity of gut microbiota and laying foundation for furtherly analysis the mechanism of disease development correlation with gut microbiota.A lot of new unknown species resources will be found in the complex conmunity of gut by culturing.In this study,two samples,which were original from two healthy donors with number AF01 and TF01,respectively,were performed to study the diversity of gut microbiota using culture-dependent method.on the one hand,pure cultured strains were isolated by using diferent mediums with rich nutrition,stress of acid and bile salt,and low nutrition.The isolates were identified by 16 S rDNA sequencing and the species taxonomy informations were retrieve from database by blast the 16 S rDNA sequences.The diversity was running statistics according the 16 S rDNA blast results.94 strains were isolated from AF01 and 71 strains from TF01.These isolates were belong to the dominant phylum of gut microbiota,including Bacteroidetes,Firmicutes,Actinobacteria and Proteobacteria.The results of potential probiotics were 23% for AF01 and 28% for TF01 by statistics.The further study the diversity of microorganisms community for AF01 was performed using 16 S rDNA sequence of V4V5 region and compared the species(OTU)difference between culture-dependent and culture-independent method.On the other hand,one of the novel species,TF01-11,which share the highest 16 S rDNA similarity of 92.8% with reference type strain,was used for polyphasic taxonomy approach on he basis of the phenotypic,chemotaxonomic,genotypic and phylogenetic characteristics comparision.Meanwhile,the whole genome sequencing of TF01-11 was performed to calculate the average nucleotide identity with the phylogenetic related reference strains and compare the genes related to biosynthesis of diaminopimelic acid,polar lipids,polyamines and teichoic and lipoteichoic acids to support the strain TF01-11 as a novel species.Finaly,The metabolic end products of TF01-11 were dected and the result showed TF01-11 was a SCFA produced bacterium,which provide supporting theories for probiotics development.