一株双歧杆菌质粒聚合酶基因的PCR扩增和鉴定

Isolation and identification of a Bifidobacterium strain with a plasmid polymerase by PCR

目的PCR扩增人双歧杆菌天然质粒的聚合酶基因。方法用改良型MRS双歧杆菌选择培养基,从人新鲜粪便分离长双歧杆菌,PCR扩增长双歧杆菌质粒聚合酶(Bifidobacterium plasmid polymerase,BPP)基因,对BPP基因检测阳性的PCR产物通过序列分析,进行鉴定。结果人长双歧杆菌天然质粒的聚合酶基因PCR扩增后,经1.0%琼脂糖凝胶电泳,测得BPP基因的相对分子质量约为1.9 kb。通过BLAST序列比对分析与GenBank中相应基因同源性为96%。结论成功克隆了1株双歧杆菌天然质粒的聚合酶基因,为构建与双歧杆菌宿主质粒相适应的载体奠定了基础。

Objective Human Bifidobacterium plasmid polymerase （BPP） gene was amplified by PCR. Methods Bifidobacterium longum was isolated from human fresh faeces samples with enhanced MRS Bifidobacterium selective medium. BPP gene of Bifidobacterium longum was amplified by PCR. The sequence of PCR positive products of BPP gene was analysed and identified. Results Native plasmid polymerase gene of a human Bifidobacterium strain was amplified by PCR. The relative molecular weight of the BPP gene was about 1.9 kilobasepairs on 1.0% agarese gel electrophoresis. It showed relatively high amino acid sequence similarity （ more than 96% ） with several plasmid . Conclusion Native plasmid polymerase gene of a human Bifidobacterium strain was cloned successfully.