[Identification of moderately halophilic strain DTY1 and study of its halotolerant mechanism].
A bacterial strain DTY1 was isolated from Caragana rhizosphere in Wuzhai, Shanxi. It was identified as Bacillus alcalophilus according to its morphological, physiological, biochemical characters and the sequence analysis of the 16S rDNA. The growth salinity of strain DTY1 was between 0 - 1.2mol/L NaCl. The optimum growth temperature and pH was 32 degrees C and 7 - 10, respectively. Strain DTY1 could accumulate 1.40mg/g ectoine in LB medium containing 0.17mol/L NaCl quantified by high-performance liquid chromatography. And the yield of ectoine improved as increasing of medium salinity. In this study, an ectB gene which potentially encoded a L-2, 4-diaminobutyric acid transaminase enzyme and involved in biosynthesis of ectoine was cloned by PCR-mediated screening from the genomic library of strain DTY1. Nucleotide sequencing indicated that the ectB gene contains 1284bp, and is predicated to encode a peptide of 427 amino acids, which shares 81% identity to that of the EctB of B. halodurans C-125. One potential sigma70 promoter and a 23bp palindromic sequence were found to locate at the upstream of ectB gene.
Zhang
Wei
W
Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100094, China. zhangw@ncepu.edu.cn
Hu
Yue-gao
YG
Zhang
Li-qun
LQ
Gao
Hong-wen
HW
D000599:Amino Acids, Diamino / Q000096:biosynthesis; D001407:Bacillus / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D001483:Base Sequence; D003001:Cloning, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D012965:Sodium Chloride / Q000494:pharmacology*
D000599:Amino Acids, Diamino; D012965:Sodium Chloride; C045628:ectoine