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从新疆石河子地区奶牛粪样中分离裂解性屎肠球菌噬菌体,对其进行纯化及生物学特性分析,为治疗和控制细菌性感染提供基础。利用双层平板培养法从奶牛粪样中分离、纯化噬菌体,并观察噬菌斑特征,将纯化后的噬菌体浓缩液用磷钨酸负染,通过透射电子显微镜观察其形态特征。对该噬菌体进行全基因组测序和遗传进化分析,用双层平板培养法测定其宿主谱、最佳感染复数、一步生长曲线、热稳定性及pH稳定性。结果如下:分离并纯化出一株裂解性屎肠球菌噬菌体,命名为vB_EfaM_XJ3,其噬菌斑圆形透明、无晕环且边缘整齐,直径1.2~1.5mm;电镜观察其头部呈廿面体,头长约53.15nm,尾长约14.42nm×199.62nm;核酸类型为dsDNA,基因组全长为157.189kb,GC含量为50.27%;其基因序列与沙门菌噬菌体SKML-39的相似性高达98%。生物学特性研究显示vB_EfaM_XJ3目前只裂解其宿主菌;最佳感染复数为0.001,潜伏期为15min,爆发期为175min,裂解量约为84;能耐受50℃左右高温,在pH 5.0~11.0范围内效价稳定。分离鉴定出一株裂解性肌尾科屎肠球菌噬菌体,对它进行了生物学特性和亲缘性分析,为沙门菌和屎肠球菌抑菌剂的研究与应用奠定了基础。
Isolation of phage of Enterobacter faecalis from cow dung samples in Shihezi region, Xinjiang, and its purification and biological characteristics analysis provide the basis for the treatment and control of bacterial infections. The phage were isolated and purified from cow dung samples by double-layer plate culture. The phage was observed. The purified phage concentrate was negatively stained with phosphotungstic acid and its morphological characteristics were observed by transmission electron microscopy. The whole genome sequencing and genetic evolution analysis of the phage were carried out. The host spectrum, optimal multiplicity of infection, one-step growth curve, thermal stability and pH stability were determined by double-layer plate culture. The results are as follows: A strain of lytic Enterococcus faecalis isolated and purified was named as vB_EfaM_XJ3. The phage were round and transparent with no halo and neat edges with a diameter of 1.2 ~ 1.5mm. The head length was about 53.15nm and the tail length was about 14.42nm × 199.62nm. The type of nucleic acid was dsDNA. The total length of the genome was 157.189kb and the content of GC was 50.27%. The similarity of its gene sequence to Salmonella phage SKML-39 was as high as 98%. The study of biological characteristics showed that vB_EfaM_XJ3 only lysed its host bacteria at present. The optimal number of infection was 0.001, the incubation period was 15 min, the burst period was 175 min, the amount of cleavage was about 84, and the temperature was about 50 ℃. Potential stability. Isolation and identification of a strain of Mycobacterium comfrey Enterococcus faecium, its biological characteristics and affinity analysis for Salmonella and Enterococcus faecium antibacterial agent research and application of the foundation.