嗜水气单胞菌毒力基因在传代过程中的稳定性研究

Stability of Virulence Genes of Aeromonas hydrophila Strains During Subculture

为了解嗜水气单胞菌毒力基因在传代过程中的稳定性,对传代前后嗜水气单胞菌(Aeromonas hydrophila,A.hy-drophila)的毒力和毒力基因进行测定和检测。采用急性毒性试验方法测定10株嗜水气单胞菌原代、第10代及第20代的菌株对异育银鲫(Carassais auratus gibebio)的半数致死量,通过聚合酶链式反应(PCR)检测原代、第10代及第20代的菌株中5种毒力基因aerA、hlyA、ahpA、altA及ast的变化情况。试验结果表明,嗜水气单胞菌在传代过程中毒力基因分布相对较稳定。但是ahpA基因极易发生变异,在培养基上连续多次传代后,毒力逐渐减弱甚至消失。可推知,ahpA基因与毒力相关性最大,并易受传代影响。

To study the stability of virulence genes of A.hydrophila strains during subculture,10 isolated A.hydrophila strains were subcultured to 20 times on LB agar.Then we observed the change of LD50 and distribution of five virulence factors（aerA,hlyA,ahpA,altA,ast）of A.hydrophila,and the virulence genes were amplified respectively by PCR from template DNA of the 10 strains and their corresponding 20 times subcultured strains.The results showed that the LD50 of Carassais auratus gibebio weakened even losed resulting from subculture,the distribution of virulence genes is no significant differences among original strains,the tenth and the twentieth times.Except that ahpA gene losed extremely resulting subculture,the genotype of virulence genes was instable relatively.