The Diversity Analysis Of Halophilic Bacteria In Sedimental Sample From Daban Salt Lake In Xinjiang And Cloning Of Na~+-transporting Gene

Halophiles living in high-salt environment, due to a wide diversity of environmental adaptation, phylogenetic diversity, unique salt tolerance mechanisms and potential applica-tions in recent years widespread attention by the scientific community. In this study, Daban Salt Lake in Xinjiang as materials deposited soil in order to obtain directional halophilic microorganisms enriched total DNA as a template of the Daban salt lake in Xinjiang diversity of halophilic bacteria, and a new sodium ion output related genes were then cloned and identified. The main conclusions were as follows:The total DNA isolated from enriched culture of sedimentary soil samples from Daban Salt Lake in Xinjiang was used as PCR template to amplify 16S rRNA gene and the library carrying 16S rRNA genes of halophilic bacteria was constructed,100 clones of the library were selected randomly and sequenced for molecular systematic analysis. Phylogenetic analysis indicated that 100 selected clones were clustered into twenty-seven species of nine genera, a lineage of the domain Bacteria. Among them, Bacillus was the most dominant genus as represents 48% of the clones, followed by Halobacillus (14%) and Halomonas (13%). Furthermore, ten clones may be potential novel species or genera. The results show that the halophilic bacteria population diversity is abundant in enriched culture of sedimentary soil from Daban Salt Lake in Xinjiang.A novel gene encoding an Na+/H+ antiporter gene was cloned from total DNA of partially digested with Sau3AI of enriched culture of sedimentary soil samples by functional complementation and expressed in the antiporter-deficient Escherichia coli strain KNabc. The gene was sequenced and designated smrL. The deduced amino acid of SmrL consists of 104, which was 59% identical to the SugE drug/H+ antiporter of Sphaerobacter thermophilus. The hydropathy profile was characteristic of a membrane protein with 3 putative transmembrane domain. smrL was the first Na+-transporting gene cloned from genomic DNA of enriched culture.The effects of NaCl and LiCl concentrations and pH7.0-8.0 conditions on the growth of E. coli KNabc cells carrying smrL gene were tested, respectively. The results show that smrL gene confer the ability upon E. coli KNabc cells to grow under NaCl and alkaline pH conditions, but no the ability of LiCl resistance.