一株沙门氏菌裂解性噬菌体的分离鉴定及生物学特性

Isolation, identification and biological properties of a lytic phage against Salmonella

摘要:

【目的】从贝类样品中分离到一株沙门氏菌裂解性噬菌体SLMP1，对其进行鉴定及生物学特性分析。【方法】采用双层平板法从贝类样品中分离沙门氏菌噬菌体SLMP1，观察噬菌斑特征，分析SLMP1的宿主范围；利用聚乙二醇8000沉淀浓缩SLMP1颗粒，用氯化铯等密度梯度离心纯化；采用透射电子显微镜观察纯化的SLMP1颗粒；采用酚-氯仿法提取SLMP1核酸，通过核酸酶处理分析核酸类型；分析SLMP1的热稳定性、pH稳定性、最佳感染复数、一步生长曲线及裂菌效果。【结果】SLMP1噬菌斑直径约2–3 mm，圆形透明、边缘清晰；SLMP1能裂解肠沙门氏菌肠亚种和鼠伤寒沙门氏菌；SLMP1头部呈二十面体，直径约62 nm，含非收缩性尾部，尾长约110 nm，属于长尾病毒科；SLMP1核酸为双链DNA；SLMP1在30–60 °C稳定，在pH 4.0–11.0稳定，最佳感染复数为0.001，感染宿主菌潜伏期为10 min、裂解期为120 min、裂解量为51；SLMP1在液体环境中具有良好的裂菌效果。【结论】SLMP1属dsDNA长尾科裂解性噬菌体，具有沙门氏菌生物抑菌剂的应用潜力。

Abstract:

[Objective] A lytic phage SLMP1 against Salmonella was isolated from the shellfish samples and identified, and its biological properties were assayed as well. [Methods] The lytic phage SLMP1 was isolated by the double-layer agar culture method. The phage plaque was observed and its host range was analyzed. Phage particles of SLMP1 were concentrated by precipitation with PEG8000 and purified by CsCl gradient centrifugation. The morphology of SLMP1 was observed by transmission electron microscopy. The genome of SLMP1 was extracted by phenol-chloroform method and the type of nucleic acid was identified with enzyme digestion analysis. The biological parameters including the thermal stability, pH stability, optimal multiplicity of infection (MOI) and the inactivation effects on the growth of Salmonella were assayed. [Results] The plaques of SLMP1 were round and transparent and their sizes were about 2–3 mm in diameter. SLMP1 can lyse Salmonella enterica subsp. Enteric and Salmonella typhimurium. SLMP1 had an icosahedral head approximately 62 nm in diameter and a long noncontractile tail with 110 nm in length. SLMP1 belongs to family Siphoviridae and is a dsDNA virus. SLMP1 was stable over a wide range of temperature (30–60 °C) and pH (4.0–11.0). The optimal MOI of SLMP1 was 0.001. One-step growth experiment showed that the latent time and burst time were 10 min and 120 min, respectively, and the burst size was 51. SLMP1 showed a good inactivation effects on the growth of Salmonella in broth. [Conclusion] SLMP1 is a dsDNA virulent phage and belongs to family Siphoviridae. The results indicated SLMP1 can serve as a promising biocontrol agent against Salmonella.