Identification of an Alga-Lysing bacteria isolated from TaiHu Lake by the analysis of 16S rRNA and 16S-23S rRNA intergenic spacer region

摘要

To characterize and identify a Alga-Lysing bacteria isolated from TaiHu Lake by the analysis of 16S rRNA and 16S-23S rRNA intergenic spacer region, genomic DNA were extracted from alga-lysing bacterial colonies isolated from TaiHu Lake. Two pairs of primer were used to amplify the sequences of 16S rRNA gene and 16S-23S rRNA intergenic spacer region. The PCR products were subcloned into pGEM?-T Easy vectors and transformed into Dh5α. Positive clones were randomly selected for sequencing. The alignment of nucleotide sequence, evolutionary distances and phylogenetic trees were analyzed by software CLUSTAL X and PHYLIP version 3.6. 16S rRNA sequence of the isolated strain showed the strain isolated from TaiHu Lake was not clustered on the same evolution branch with the most type-strains except for Pseudomonas aeruginosa strain LMG 1242T. The blast result between strain isolated and Pseudomonas aeruginosa strain LMG 1242T showed that there were three different base pairs lied in the sites of 398, 1094, and 1302. The homology of the two strains reached 99.8%. ISR sequence of the isolated strain showed the highest homology with Pseudomonas aeruginosa strain UCBPP-PA14 as to 95.6%. Compared with sequences in the GenBank nucleotide database, the bacterial strains isolated was primarily identified as Pseudomonas sp. By the 16S rRNA gene and 16S-23S rRNA intergenic spacer region analysis.