| A survey on culturable bacterial diversity in Xinjiang and Tibet was carried out. These two areas are rich in radiation, poor in nutrient factors with huge differences in temperatures between day and night. 682 bacterial strains were isolated from samples taking from these two areas, within which 260 strains were initiatively identified. During the isolation course, an effective cultivation strategy for recovering most bacterial diversity from Xinjiang was developed. A large number of bacterial potential new taxa were recovered due to the improved cultivation methoed. Data analysed for bacterial diversity in this paper was done by all the students in the laboratory and available in the website given below. The result indicated that samples from Xinjiang and Tibet shared a similar pattern in culturable bacterial community. Gram-positive bacteria with a tough cell wall and high tolerance to the environmental stress numerically dominated in the isolated strains. According to the diversity index and abundance plot, samples from Xinjiang showed higher diversity and evenness than that from Tibet.A polyphasic taxonomic approach is used to identify four newly recovered bacterial strains. Strain 12116T and 12157T were isolated from a soil-sand mixture sampled from Xinjiang, China. Phylogenetic analysis based on the 16S rRNA gene sequences showed that they were mostly related to the members of the genus Dyadobacter and Pedobacter, with similarities ranging from 94.7% to 96.6% and 90.0% to 93.7% respectively. Chemotaxonomic properties support the monothetic phylogenetic classification of strain 12116T and 12157T as a member of the genus Dyadobacter and Pedobacter severally. Aslo this two isolates exhibited sufficient phenotypic differentiation and phylogenetic and genetic distinctiveness. Therefore, two novel species Dyadobacter alkalitolerans and Pedobacter xinjiangensis were proposed, each represented by strain 12116T and 12157T.Strain TYLN1T was a Gram-positive, non-motile, facultative anaerobic actinobacteria, isolated from an air sample in campus of Wuhan University. The strain grew optimally at pH 7.0 and 30℃. Analysis of 16S rRNA gene sequence similarities revealed that the organism belongs to the genus Aeromicrobium. The G+C content of the strain was 73.3 mol%. The cell wall diamino acid was LL-2,6-diaminopimelic acid. The predominant menaquinones were MK-9(H4) and MK-8(H4). The major fatty acids were C18:1ω9c, C18:0 and C16:0. These chemotaxonomic data mentioned above also supported the affiliation of strain TYLN1T to the genus Aeromicrobium. The values for DNA-DNA hybridization between strain TYLN1T and the phylogenetically most closely related species A. tamlense SSW1-57T and A. panaciterrae Gsoil 161 T were 35% and 11.5%, respectively. On the basis of the polyphasic data from this study, the isolate represents a novel species, for which the name Aeromicrobium flavum sp. nov. is proposed.Strain X16-7T was isolated from a sand sample from Xinjiang. The isolate was clustered with both Massilia species and Naxibacter species in the phylogenetic tree constructed on the basis of 16S rRNA gene sequences. It showed a similar pattern of biochemical and physiological features with the genus Naxibacter, while different from Massilia species, especially in the terms of cellular fatty acid profile. These results convinced that strain X16-7T belongs to the genus Naxibacter. However, the isolate showed sufficient phenotypic, phylogenetic and genetic differentiations from known Naxibacter species. In all, strain X16-7T should represent a novel species of the genus Naxibacter, for which the name Naxibacter deserti was proposed. Website:http://www.cctcc.org/tmbiology/microbe_common/search.php... |
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