| In this study,the skin microbiota from the forehead of the high-altitude Tibetans(n=10)were collected and cultured in 5 different media.Same DNA extraction method was used for the culture plates and the skin samples for 16 S r RNA sequencing to explore the diversity and culturability of human skin microbiota.The cultured bacterial colonies were purified,isolated,and identified to obtain human skin bacterial resources.A mouse model of subacute photodamage was constructed with the bacterial colonization and UV irradiation of the skin,and the strains with potential application value for UV radiation protection of the skin were screened.The research content and results are as follows:1.At the phylum level,Proteobacteria(44.48%),Firmicutes(27.1%),Actinobacteria(13.3%)and Bacteroidetes(9.57%)were the four most abundant phyla in Tibetan skin microbial communities.At the genus level,the top ten taxa were Pseudomonas(10.20%),Enhydrobacter(8.76%),Chryseobacterium(6.90%),Staphylococcus(5.85%),Acinetobacter(3.68%),Clostridium-sensu-stricto-1(3.32%),Bacillus(2.89%),Sphingomonas(2.37%),Peptoclostridium(2.35%)and Psychrobacter(2.26%).2.The cultivable portion of the skin microbiota was determined by comparing the operational taxonomic units(OTUs)recovered by 16 S r RNA sequencing of the culture plates to OTUs from culture-independent sequencing of the skin sample.An average of19.74% of all OTUs observed in culture-independent sequencing of the skin samples were also detected in culture-enrichment(cultured samples).Using thresholds of 0.01% and0.1 %(in the culture-independent sequencing),an average of 27.14 and 47.67% of OTUs were cultured,respectively.Above 0.1 % relative abundance,the largest proportion of OTUs cultured was 82.14% from the skin12.3.A total of 340 strains of bacteria were isolated from culture,including 4 phyla and42 genera at the level of 24 families.4.The animal model experiment preliminarily explored the protection of skin from UV radiation by strains that consist of Arthrobacter gandavensis,Bacillus psychrosaccharolyticus,Erwinia soli,Paenibacillus amylolyticus,Paenibacillus terrae,and Psychrobacter psychrophilus.After skin bacteria colonization and UV irradiation,the skin slices were scored according to the pathological lesion grade.The skin morphology and tissue score results showed that the significant difference between the experimental group C(Erwinia soli)and the blank control group(UV irradiation group).(p < 0.01).This study reveals that the skin of high-altitude Tibetans is rich in microbial communities and has great potential for application in skin protection.Using a combination of culture and 16 S r RNA gene sequencing,we present that the majority of the bacteria identified by 16 S r RNA sequencing of the skin microbiota can be cultured too. |
