摘要
目的从污水中分离出一株新的粪肠球菌噬菌体,对其进行鉴定及生物学特性分析,为食品中粪肠球菌污染防治提供新思路。方法宿主菌来源于牦牛屠宰加工环节,并经16S rRNA测序鉴定;从环境下水道污水中分离噬菌体,将噬菌体进行分离纯化,采用双层平板法测其效价;通过透射电镜观察噬菌体形态;测定其裂解谱、最佳感染复数、一步生长曲线,以及测定pH、紫外照射、温度、有机溶剂对噬菌体效价的影响;并测定其对宿主菌的裂解效力。结果宿主菌经16S rRNA测序鉴定为粪肠球菌;从污水中分离出一株能裂解粪肠球菌的噬菌体命名为P45;电镜结果表明此噬菌体为蝌蚪状的长尾噬菌体,头部呈六面体,整体长度约为(200±5)nm;通过裂解谱测定,发现该噬菌体对其中4株粪肠球菌有明显裂解效果;最佳感染复数为0.1、潜伏期为50 min、裂解周期为190 min、裂解量为1 PFU/cell;噬菌体能在pH=2和pH=13存活,效价分别为1.05×10^(2)PFU/mL和1.85×10^(3)PFU/mL;75℃高温可使该噬菌体完全失活;紫外照射使噬菌体效价下降;噬菌体对有机溶剂不敏感;对宿主菌有较好的裂解效果。结论粪肠球菌的噬菌体对宿主菌有良好裂解效果,对食品中粪肠球菌的污染防控有一定应用潜力。
Objective To isolate and identify a bacteriophage of Enterococcus faecalis and to analyze its biological characteristics.Methods The host bacteria was isolated from the process of yak slaughtering and identified by 16S rRNA sequencing.The bacteriophage was isolated from the environmental sewage and was purified.The titer of bacteriophages was determined using the double-layer plate method.The morphology of bacteriophage was observed by transmission electron microscopy;the bacteriophage lysis profiles,optimal infection complex,and one-step growth curve were determined;the effects of pH,UV irradiation,temperature,and organic solvents on bacteriophages have been studied.Furthermore,the lytic activity of the bacteriophage against the host bacteria was determined.Results The host bacteria were identified as E.faecalis by 16S rRNA sequencing.A bacteriophage named P45 was isolated from sewage to lyse E.faecalis.Electron microscopy showed that the bacteriophage was a tadpole-shaped long-tailed bacteriophage,which has a hexahedral head and its length is(200±5)nm.The bacteriophage had obvious lysis effect on four strains of E.faecalis.Bacteriophage’s optimal multiplicity of infection was 0.1.The results of one-step growth curve showed that the incubation period was 50 min,the lysis period was 190 min,and the burst size was 1 PFU/cell.This bacteriophage survived at pH=2 to 3,which titers were 1.05×10^(2)PFU/mL and 1.85×10^(3)PFU/mL.At 75℃,this bacteriophage was completely inactivated.Bacteriophage’s titer was decreased by UV irradiation,and it was not sensitive to organic solvents.Conclusion This bacteriophage has a good lysis effect and has potential application on the prevention or control of E.faecalis contamination.
作者
王金丽
尹红梅
朱成林
蔡自建
陈娟
唐俊妮
WANG Jinli;YIN Hongmei;ZHU Chenglin;CAI Zijian;CHEN Juan;TANG Junni(College of Food Sciences and Technology,Southwest Minzu University,Sichuan Chengdu 610025,China)
出处
《中国食品卫生杂志》
CSCD
北大核心
2024年第7期818-826,共9页
Chinese Journal of Food Hygiene
基金
西南民族大学中央高校基本科研业务费专项资金优秀学生培养工程项目(2023NYXXS068)。
关键词
粪肠球菌
噬菌体
生物学特性
裂解效果
Enterococcus faecalis
bacteriophage
biological characteristics
lytic effect
