中文摘要：

根据GenBank公布的嗜水气单胞菌（Aeromonas hydrophila,Ah）转录调控蛋白基因ahyR序列设计1对特异性引物，利用PCR方法扩增AhJ-1株ahyR的部分片段。PCR产物克隆入pMD18-T载体，经序列测定后定向连接入含有卡那霉素抗性（Kan）基因的自杀性质粒pJP5603中，构建重组质粒pJP-ahyR。将鉴定为阳性的重组质粒转化嗜水气单胞菌J-1株感受态细胞，获得1突变株细菌。PCR方法鉴定该突变株为J-1株ahyR基因同源突变株，命名为J-1△ahyR。与J-1株相比，突变株的外膜蛋白图谱和部分生化特性发生改变；胞外蛋白酶、淀粉酶、DNA酶、溶血素等几种主要毒力因子同时丧失；致病力明显降低，对小白鼠的半数致死量大于1．0×10^8 CFU（colony forming units）。该研究为ahyR基因功能的探讨及嗜水气单胞菌弱毒疫苗的研制奠定了基础。

英文摘要：

According to the relevant nucleotide sequence from GenBank, a pair of specific primers was designed to amplify the partial fragment of ahyR gene from Aeromonas hydrophila （Ah） J-1 strain by PCR. The PCR product was cloned into pMD18-T vector, and aider sequencing, ligated into the suicide plasmid pJP5603 which contains a Kan resistant gene to get a recombinant plasmid pJP- ahyR. A mutant strain was obtained after the positive recombinant plasmid was transformed into the J-I strain. On the basis of PCR, an ahyR gene homologous recombinant mutant strain named J-I △ ahyR was confirmed. Compared with Ah J-I strain, outer membrane protein profiles and some biochemical characters of the mutant strain had changed, and some genes of main virulent determinants could not be expressed, such as proteases, amylase, DNase and hemolysin. In addition, the pathogenicity capability was greatly decreased and the 50% lethal dose for mice was more than 1.0×10^8 CFU（colony forming units）. The experimental results will apply a basis for studying ahyR gene function and developing the attenuated vaccine against Aeromonas hydrophila.