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目的:以大肠杆菌285为宿主菌从医院污水中分离噬菌体,对其生物学特点进行研究,并与f2噬菌体的生物学特点进行比较。方法:四步法污水分离噬菌体;单、双层平板噬菌斑实验筛选烈性噬菌体并观察噬菌斑形态;纯化后2%磷钨酸染色电镜观察;利用双层平板噬菌斑实验测定最佳感染复数;紫外线照射观察耐受时间。结果:成功分离出大肠杆菌285烈性噬菌体2株(EcP1、EcP2),EcP1噬菌斑直径3~5 mm(培养12 h),逆光观察噬菌斑呈全透明状,该噬菌体有一个长多面体立体对称的头部,头长径(L)约47 nm,头横径(W)约35 nm,L/W=1.34,无囊膜,有一短尾,尾长约20 nm;EcP2噬菌斑直径约1 mm(培养12 h),逆光观察噬菌斑呈全透明状,该噬菌体有一个长多面体立体对称的头部,头长径(L)约89 nm,头横径(W)约54 nm,L/W=1.65,无囊膜,有一长尾,有尾鞘,尾长约81 nm。EcP2可噬大肠杆菌8099形成直径约1 mm的圆形噬菌斑。f2噬大肠杆菌285形成圆形直径2~3 mm的噬菌斑,逆光观察噬菌斑呈全透明状,f2呈微球形,直径51~113 nm。EcP1和EcP2最佳感染复数分别为10和0.1,在紫外灯(光强221μW/cm2)下暴露8和4 min可全部失活。结论:按照国际病毒分类委员会分类标准,所分离的两株噬菌体分属于短尾噬菌体科(EcP1)和肌尾噬菌体科(EcP2)烈性噬菌体,按照Bradley和Ackermann形态分类法分属于C2亚群和近似A2亚群;其中EcP2为一株宽噬噬菌体。两株噬菌体头部大小较呼吸道病毒中流感病毒、副黏病毒、冠状病毒都小。
OBJECTIVE: To isolate bacteriophages from hospital sewage by using Escherichia coli 285 as host bacteria, and to study its biological characteristics and compare with the biological characteristics of f2 bacteriophage. Methods: Four-step method was used to separate phage from wastewater. Single and double-layer plaque experiments were performed to screen for the strong phage and to observe the morphology of the plaques. The purified samples were analyzed by 2% phosphotungstic acid staining, Infection multiples; UV exposure observed tolerance time. RESULTS: Two strains of Escherichia coli 285 bacteriophage (EcP1 and EcP2) were successfully isolated. The diameter of EcP1 plaques was 3 ~ 5 mm (cultured for 12 h). The bacteriophage plaque was completely transparent under light exposure. The bacteriophage had a long polyhedron Symmetrical head with a long axis (L) of about 47 nm, a head transverse diameter (W) of about 35 nm, a L / W of 1.34, and a short tail with a tail length of about 20 nm. EcP2 plaque diameter About 1 mm (cultured for 12 h), and the bacteriophage showed full transparency by backlighting. The bacteriophage had a long, symmetrical head with a long axis (L) of about 89 nm and a first transverse axis (W) of about 54 nm , L / W = 1.65, no capsule, a long tail, a tail sheath, tail length of about 81 nm. EcP2 can Escherichia coli 8099 form a round plaque about 1 mm in diameter. f2 Escherichia coli 285 formed a 2 ~ 3 mm diameter circular plaque, bacterioplasty was full transparency under the light microscope, f2 microspheres with a diameter of 51 ~ 113 nm. The optimal number of EcP1 and EcP2 were 10 and 0.1, respectively, and all of them were inactivated at 8 and 4 min exposure to ultraviolet light (light intensity 221 μW / cm2). Conclusion: According to the classification standard of the International Virus Classification Committee, the two phages belong to EcP1 and EcP2 bacteriophage belong to the bacteriophage phage, and belong to the C2 subgroup according to Bradley and Ackermann morphological classification A2 subpopulation; EcP2 is a wide phage phage. Two phage head size than the respiratory virus influenza virus, paramyxovirus, coronavirus are small.