Analysis of molecular biological characteristic of the gene and its flanking sequences, similar with transposase in Vibrio cholerae pathogenicity island, among V. alginolyticus strains

Abstract:

[Objective] To investigate whether the gene similar with transposase gene (vpiT) from pathogenicity island of Vibrio cholerae exists in V. alginolyticus strains, and to analyze molecular biological characteristic of the gene and its flanking sequences. [Methods] PCR detection of the gene, similar with vpiT in pathogenicity island of V. cholerae was done among 94 strains of V. alginolyticus,. PCR products from positive strains were directly sequenced. Based on acquired partial sequences, we designed primers for reverse PCR, and got the amplification fragment containing complete gene (valT) from V. alginolyticus E0601, which was similar with vpiT gene. The reverse PCR product was cloned and sequenced, and the acquired sequence was analyzed with bioinformatic methods. [Results] We found that among 94 V. alginolyticus strains, only V. alginolyticus E0601 and E0612，from east coastal areas of Guangdong province, produced predicted positive amplification fragments in PCR detection. Sequencing indicated that amplification fragments from V. alginolyti-cus E0601 and E0612 had identical DNA sequence (named valT-S1). Sequence valT-S3 from V. alginolyticus E0601, con-taining complete valT gene and flanking segments, was finally obtained through reverse PCR, cloning, and sequencing. Bioinformatic analysis on valT-S3 suggested that valT was transposase gene, highly similar with vpiT in V. cholerae VPI. [Conclusion] According to above result and related references, we believe that valT and its flanking segments were acquired from heterogenous bacteria, and VPI or its component probably transfers among Vibrio species including V. alginolyticus.