两株副溶血弧菌烈性噬菌体的分离鉴定

研究旨在筛选烈性噬菌体, 为副溶血弧菌(Vibrio parahaemolyticus, Vp)病害防控增加新的选择。以副溶血弧菌Vp13为宿主菌, 通过二层琼脂平板法筛选, 分离到了2株烈性噬菌体SX-2和SX-F。对其形态结构进行了透射电镜观察, 利用DNase I、 RNase A、Mung Bean Nuclease和Hind Ш酶进行噬菌体核酸类型鉴定, 并对噬菌体的裂解谱、最佳感染复数、一步生长曲线进行了测定。透射电镜观察结果显示: SX-2核衣壳头部长约110 nm, 宽约50 nm, 尾部长约150 nm, 宽约10 nm, 为典型的复合体制; SX-F核衣壳呈正六边形, 长约为56.86 nm,宽约50.74 nm, 未观察到尾部, 推测为正二十面体对称; 核酸测定结果显示两者均为线性双链DNA。依据国际病毒分类委员会第九次报告, SX-2符合肌尾噬菌体科特征, SX-F符合盖噬菌体科特征。噬菌体SX-2和SX-F对85株弧菌裂解结果显示: 噬菌体SX-2能够裂解23株副溶血弧菌和1株溶藻弧菌(Vibrio alginolyticus), 噬菌体SX-F能够裂解19株副溶血弧菌和1株溶藻弧菌。SX-2和SX-F的最佳感染复数均为0.0001。一步生长曲线结果显示: SX-F的潜伏期约10min, 裂解期约70min, 裂解量为116.2; 噬菌体SX-2的潜伏期小于10min, 裂解期大约70min, 裂解量为209.3。两株噬菌体生物学特性表明SX-2与SX-F均为烈性噬菌体, 这为进一步探讨噬菌体防治技术奠定了基础。

ISOLATION AND IDENTIFICATION OF TWO LYTIC PHAGES AGAINST VIBRIO PARAHAEMOLYTICUS

The aim of this study was to screen lytic phase and provide new alternatives for the prevention and control of V. parahaemolyticus. In this study, two lytic phages SX-2 and SX-F were isolated by double-layer plate method against the host bacteriaV. parahaemolyticus Vp13. The morphological structures of these two phages were observed by trans-mission electron microscope (TEM). The types of nucleic acids were identified by the degradation characteristics of DNase I,RNase A,Mung Bean Nuclease andHind Ш. The lysis spectrum, optimal multiplicity of infection and one step growth curve of SX-2 and SX-F were also analyzed. The results of TEM showed that the capsid protein of lytic phage of SX-2 was a complex symmetry with icosahedral symmetry head that had length of about 110 nm and width of about 50 nm and a spiral symmetry tail that had length of about 110 nm and width of about 10 nm. SX-F showed hexagon with length of about 56.86 nm and width of about 50.74 nm without a tail, which was icosahedral symmetry. Both SX-2 and SX-F were linear double stranded DNA bacteriophage. They were belonged to the family ofMyoviri-dae andTectivirus based on the taxonomy standard of the ninth report of the International Committee Taxonomy of Viru-ses. Results of lytic experiment on 85Vibrio strains showed that phage SX-2 could lysis 23 strains ofV. parahaemolyti-cus and one strain ofVibrio alginolyticus, and phage SX-F could lysis 19 strains ofV. parahaemolyticus and one strain ofV. alginolyticus. The optimal multiplicity of infection of plase SX-2 and SX-F were 0.0001. One step growth curve showed that the incubation period of phage SX-F was about 10min, the lytic cycle was 70min, and the burst size was 116.2. The incubation period of the phage SX-2 was less than 10min, and the lytic cycle was about 70min, and the burst size was 209.3. These results indicated that both of them were lytic phages, which can be used as an alternative to con-trol and prevention of theV. parahaemolyticus.