大肠埃希菌噬菌体的分离鉴定及其生物学特性研究

Identification and biological properties of Escherichia coli phages isolated from raw sewage

目的通过分离鉴定大肠埃希菌噬菌体,研究其生物学特性。方法利用噬菌斑法从环境污水中分离和鉴定大肠埃希菌噬菌体,采用负染法电镜观察噬菌体的形态和大小;提取噬菌体的基因组并进行酶切电泳分析,测定噬菌体感染复数并观察其一步生长曲线。结果通过噬菌斑法分离出9株大肠埃希菌噬菌体。电镜显示,噬菌体头部呈立体对称,有一长尾。琼脂糖凝胶电泳显示,噬菌体基因组大小约30kb。生长曲线表明噬菌体感染宿主菌的潜伏期为23min,爆发时间为39min,裂解量为78。结论9株大肠埃希菌噬菌体中有6株具有较广的噬菌谱,潜伏期短,裂解量明显,为深入研究大肠埃希菌噬菌体的生物学特性及其功能提供了依据。

Objective To investigate biological properties of phages, Escherichia colt phages were isolated from raw sewage. Methods Bacteriophages were identified using plaque methods, the electron micrographics of phages was carried out to observe the morphology and size of E. colt phage by negative-staining. The extraction of phage genome and the electrophoresis of DNA were performed. Multiplicity of infection and growth curve of phages were determined. Results Nine strains of E. colt phages were identified. Electron micrographics showed that E. colt phages exhibit a cubic symmetry, and these phages have a long tail. Electrophoresis of DNA demonstrated that the size of phage genomes was around 30 kb. The growth curve showed that the incubation period was 23 min, the time of burst phase was 39 min, and the burst size was 78. Conclusion Six strains of phages have a abroad host range in E. coli, a shorter incubation period, and a apparent burst size. These data enable us to explore more properties of E. colt.