致病性鸡大肠杆菌Ⅰ型菌毛fimA基因的克隆和同源性分析

Cloning and homology analysis of typeⅠpili fimA gene from avian pathogenic Escherichia coli strain

根据Genbank已发表的致病性鸡大肠杆菌(Avian pathogenic Escherichia coli,APEC)Ⅰ型菌毛fim A基因序列,设计并合成了位于fim A基因保守区的1对引物.应用PCR技术以鸡大肠杆菌标准株和分离株DNA为模板,扩增到片段长为549 bp的阳性产物;经酶切、连接、转化和筛选,得到fim A基因,并克隆、测序;运用DNAStar软件对核酸序列分析,确定所扩增和克隆的DNA片段为fim A基因.

According to the published fimA gene sequences of typeⅠpili from avian pathogenic Escherich-ia coli, one pair of primers were designed and synthesiz based on the conservative regions of fimA gene. A DNA fragment of 549 bp was generated by polymerse chain reactin （ PCR） with DNA extracred from the standard strain and the isolated strain of Escherichia coli.The fimA gene was cloned into pMD18-T plasmid.The nucleotide sequences of the DNA fragment were analysed by DNAStar software, the results showed that the cloned DNA fragment encodes a fimA gene.