【摘要】 目的 :分离携带天然质粒的人双歧杆菌。方法 :用自制的改良型Blb双歧杆菌选择培养基 ,从人新鲜粪便分离双歧杆菌 ,对初步质粒检测阳性的单菌落通过糖发酵试验、(G +C)mol%测定和 16SrDNA序列分析 ,进行菌株鉴定。结果 :筛选到一株携带天然质粒的人双歧杆菌 ,编号B2 0 0 30 4 ,在 1 0 %琼脂糖凝胶上 ,测得质粒的相对分子质量约为 2 2kb。通过对该菌株的形态学观察和糖发酵试验等生理生化特征研究 ,证明该菌株为两歧双歧杆菌 (Bifidobacteriumbifidum ) ;HPLC法测得其 (G +C)mol%为 5 5 6 ,16SrDNA序列分析进一步证实该菌株为两歧双歧杆菌。结论 :分离得到一株携带天然质粒的人两歧双歧杆菌新菌株。更多还原

【Abstract】 Objective: To isolate a Bifidobacterium with a native plasmid for genetically engineering manipulation.Methods:The human faeces sample was selected with a kind of enhanced selective medium for Bifidobacterium based on Blb medium.The flora was detected to ensure plasmid preliminarily.Then the flora which contained plasmid was identified base on its phenotypic characteristics and its carbohydrate fermentation profiles.The (G+C)mol% value and the 16S rDNA sequence analysis were also employed to its characterization.Results:A Bifidobacterium strain,numbered B200304,with a native plasmid was isolated.The relative molecular weight of the plasmid was about 22 kilobasepairs on 1.0% agarose gel electrophoresis.According to its carbohydrate fermentation trial and its(G+C)mol% value,the Bifidobacterium strain was identified as B.bifidum preliminarily.Further,the specific 16S rDNA sequence analysis also confirmed the preliminary result. Conclusion:The isolated Bifidobacterium strain with a native plasmid was a novel B.bifidum strain with a native plasmid was a novel B.bifidum strain.更多还原