嗜水气单胞菌气溶素基因的克隆与序列分析

Cloning and Nucleotide Sequence Analysis of Aerolysin Gene of Aeromonas hydrophila

以嗜水气单胞菌BZ和NK分离株的DNA为模板，采用PCR技术，扩增气溶素基因（aerA）的DNA片段，将其克隆到pMD18-T载体上。通过序列测定，分析结果表明-所克隆的1393bp片段为aerA部分序列，编码产生464个氨基酸。BZ与NK之间aerA核苷酸同源性为97．6％，氨基酸同源性为98．3％，与其它分离物核苷酸同源性为71．6％～97．5％，氨基酸同源性为68．0％～98．9％。利用邻接法构建了aerA分子树状图，树状图分析表明：气单胞菌属各分离物聚为三支，其中嗜水气单胞菌各菌株之间关系密切，被聚类为同一支。

The aerolysin genes （aerA） of BZ and NK isolates were cloned and sequenced. The sequence analysis showed that the partial aerA of BZ and NK isolates consisted of 1393 bp, encoding a protein of 464 amino acids. The similarity of nucleotide and amino acid sequences of aerA between BZ and NK isolates was 97.6% and 98.3% respectively. The nucleotide sequence of aerA of BZ strain exhibited 71.6% to 97.5% homology with other Aeromonas isolates, and the amino acid sequence exhibited 68.0% to 98.9% homology. The phylogenetic tree based on aerA nucleotide sequences from Aeromonas isolates was constructed with neighbor-joining method. It showed that there were three branches of aerolysin genes, and a close relationship among Aeromonas hydrophila isolates which were clustered into the same branch.