Genetic analysis of the br gene in halophilic archaea isolated from Xinjiang region, China

Some novel members of extremely halophilic archaea,strains AJ11,AJ12 and AJ13,were isolated from the Aularz Lake located in the Altun Mountain National Nature Reserve of Xinjiang,Uygur Autonomous Region in China.Partial DNA fragments encoding a bacteriorhodopsin(BR),as well as for 16S rRNA of isolated strains,were amplified by PCR and their DNA sequences were determined subsequently.On the basis of homology and phylogenetic analysis of the 16S rDNA,we thought that the isolated strains forming a microbiological population are the members of the genus Natrinema.The results of genetic analysis,such as GC content,transition/transversion(Ti/Tv)rate ratios and synonymous substitution rates(Ks)indicate that the br fragments,with a high level of genetic divergence,are faced with both purifying selection and bias mutation pressure.The study provides the basis for use of species and BR proteins resources.

Isolation and Phylogenetic Analysis of Halophilic Archaeon AJ6

Halophilic archaeon AJ6 was isolated and purified from the Altun Mountain National Nature Reserve of the Xinjiang Uygur Autonomous Region.Strain AJ6 is a Gram-negative rod whose size is 0.2–0.6 by 1.6–4.2μm,wherein a few cells are globular.The optimum salt concentration for its growth is 20%NaCl and 0.6%Mg^(2+),and the optimum pH is 6.0–7.0.Morphological,physiological,and biochemical characteristics of strain AJ6 were observed.The 16S rRNA encoding gene(16S rDNA)sequence of strain AJ6 was amplified by PCR,and its nucleotide sequence was determined subsequently.“Clustalw”and“PHYLIP”software bags were used to analyze the 16S rDNA sequence;the homology was compared,and then the phylogenetic tree was established.The results indicate that strain AJ6 is a novel species of the genus Natrinema.The GenBank accession number of the 16S rDNA sequences of strain AJ6 is AY277584.