明永冰川融水中一株裂解性低温噬菌体的分离及特征

Isolation and characterization of a lytic bacteriophage from Mingyong glacier melt water

摘要:

摘要:【目的】高山冰川是一类独特的生态系统，本研究探索从明永冰川地区分离和培养低温菌噬菌体，并对其特征进行研究。【方法】利用已分离的低温菌为宿主，采用“双层平板法”从明永冰川融水中分离纯化低温菌噬菌体;对噬菌体及其宿主进行电镜形态观察，并进行噬菌体基因组限制性酶切片段长度多态性分析、衣壳蛋白组成分析及噬菌体生理特征研究。【结果】从明永冰川融水中分离获得一株裂解性低温噬菌体，命名为MYSP03(Mingyong Flavobacterium Siphoviridae Bacteriophage)，其宿主菌MYB03 鉴定为Flavobacterium 菌株。噬菌体MYSP03 为长尾型，无囊膜，头部具典型的正多面体立体对称结构，直径约72 nm;尾管长约240 nm，直径约10 nm;4℃时具侵染活性，在4℃－20℃范围内均可产生边缘清晰、透明的噬菌斑，最适感染温度约10℃，pH 耐受范围较广，最适感染pH 约9.4，对氯仿不敏感，基因组为双链DNA，大小约66 kb。

Abstract:

Abstract:［Objective］Glacier is a unique ecological system． This study focused on the isolation and characterization of a cold-active bateriophage from Mingyong glacier area in northwest Yunnan． ［Methods］ Bacterial strains isolated from glacial melt water were used as host cells to isolate and purify bacteriophages by double-layer plate method． The morphology of the isolated phages and their host strains were observed by electron microscope． Restriction fragment length polymorphism (RFLP) analysis of genomic DNA，constituent proteins and physiological analysis of the bacteriophages were further carried out to characterize the phages． ［Results］A lytic cold-active bacteriophage，designated as MYSP03，was isolated from Mingyong glacier． Its host strain MYB03 was identified as a member of genus Flavobacterium，based on the 16S rRNA sequence analysis． The bacteriophage MYSP03 has a isometric head (about 72 nm in diameter) and a long tail (about 240 nm in length and 10 nm in width)，but no envelope was detected． Physiological analysis results showed that MYSP03 had infection activity at 4℃，and clear and transparent plaques were formed on double-layer plates between 4 and 20℃． Its optimum infection temperature was 10℃ and optimal pH 9. 4，respectively． It is insensitive to chloroform．Furthermore，the genome of MYSP03 consists of double-stranded DNA and is approximately 66 kb．