两株大肠杆菌烈性噬菌体的分离与生物学特征研究  

Isolation of Escherichia coli phages and their biological characteristics

作　　者：于龙[1] 王洁[1] 赵建军[1] 温占波[1] 杨文慧[1] 李娜[1] 鹿建春[1] 李劲松[1] 

机构地区：[1]军事医学科学院微生物流行病研究所,病原微生物生物安全国家重点实验室,国家生物防护装备工程技术研究中心,北京100071

出　　处：《军事医学科学院院刊》2008年第5期432-435,共4页Bulletin of the Academy of Military Medical Sciences

基　　金：国家科技攻关课题(2004BA719A15)

摘　　要：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，并与亿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—5mm（培养12h），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47nm，头横径（W）约35nm，L／W=1．34，无囊膜，有一短尾，尾长约20nm；EcP2噬菌斑直径约1mm（培养12h），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89nm，头横径（W）约54nm，L／W=1．65，无囊膜，有一长尾，有尾鞘，尾长约81nm。EcP2可噬大肠杆菌8099形成直径约1mm的圆形噬菌斑。记噬大肠杆菌285形成圆形直径2～3mm的噬菌斑，逆光观察噬菌斑呈全透明状，f2呈微球形，直径51～113nm。EcP1和EcP2最佳感染复数分别为10和0．1，在紫外灯（光强221μW／cm^2）下暴露8和4min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。Objectives： To isolate the bacteriophages of Escherichia coli 285, and study their biological characteristics as well as compare it with phage f2. Methods： E. coli 285 was used as the host to isolate phages from the raw sewage from the sewage treatment center of a hospital. The phages isolated successfully were subjected to plaque forming unit （PFU） assay using single or double layer agar plate method. Morphological property of the plaques was observed, and finally optimal multiplicity of infection（MOI） was determined. Both phages were examined by electron microscopy. Their survival rate after exposure to ultraviolet（UV） ray was determined. Results： Two phage strains of E. coli 285 （named EcP1 and EcP2） were isolated successfully from the raw sewage, and their lysis properties were constant. Plaques of both EcP1 and EcP2 were transparent, about 3 - 5 mm and nearly 1 mm in diameter, respectively. EcP2 could also lyse E. coli 8099 besides E. coli 285 to form clear plaques about 1 mm in diameter. Both of them belonged to tailed phage. Phage EcP1 had an elongated head （about 47 nm in length and about 35 nm in width） and a short tail （about 20 nm in length）. Phage EcP2 had an elongated head （about 89 nm in length and about 54 nm in width） and a contractile tail （about 81 nm in length）. The optimal MOI of phages EcP1 and EcP2 was 10 and 0.1 ,respectively. They lost their abilities to form plaques on double layer agar plate after exposure to UV ray, for 8 min and 4 min, respectively. Conclusion： Phages EcP1 and EcP2 belong to tailed families：Podoviridae and Myoviridae, respectively. Thereinto EcP2 is a broad host range phage. The diameters of their heads are smaller than that of some respiratory viruses.

关 键 词：大肠杆菌 噬菌体 分离 生物学 形态学 

分 类 号：R378.2[医药卫生—病原生物学]