大鲵虹彩病毒理化及生物学特性研究

对大鲵虹彩病毒(Giant salamander iridovirus,GSIV)的理化特性及生物学特性进行了研究。结果表明:GSIV对热处理敏感,56℃和65℃处理30 min均可彻底灭活病毒;GSIV经酸(pH3)和碱(pH10)处理,病毒滴度(TCID50)与对照组相比较分别下降了8.58、9.04个对数级,差异极显著(P<0.01);GSIV经有机溶剂氯仿、乙醚以及胰蛋白酶处理,TCID50与对照组相比较分别下降了9.33、7.83、6.49个对数级,差异极显著(P<0.01)。冻融次数对GSIV滴度的影响不显著(P>0.05)。GSIV对细胞培养物的感染性试验结果表明,GSIV可在鲤上皮瘤细胞系(Epithelioma papilloma cyprini,EPC)、斑点叉尾鮰肾脏细胞系(Channel catfish kidney,CCK)、虹鳟鱼性腺细胞系(Rainbow trout gonadal,RTG-2)等细胞中增殖,但在EPC、CCK细胞中增殖速度快,TCID50高;GSIV在EPC细胞中的最适生长温度是25℃。GSIV在EPC细胞中增殖动态试验结果表明,GSIV感染细胞6 h后TCID50开始快速上升,进入对数增长期,72 h时TCID50达到最大值,以后趋于稳定。GSIV感染EPC细胞超薄切片透射电镜观察结果显示,在EPC细胞质中可见大量虹彩病毒样颗粒,呈晶格状排列,直径约140 nm。

Studies on the physical,chemical and biological characteristics of giant salamander iridovirus

The giant salamander iridovirus(GSIV) is the causative agent of a viral hemorrhagic disease of cultured Chinese giant salamanders.In this paper,the physical,chemical and biological characteristics of GSIV were fully investigated.The results indicated that GSIV treated by 56 ℃ or 65 ℃ for 30 min,the virus infectivity was completely inactivated;Treated by acid(pH 3) and alkali(pH 10),the viral titers(TCID50) decreased by 8.58,9.04 log10 compared with the untreated group,respectively(P<0.01);Treated by chloroform,ethyl ether and trypsin,the viral titers decreased by 9.33,7.83,6.49 log10,respectively(P<0.01).The titer of GSIV was not affected by the times of frozen-thawed treatment(P>0.05).The results of GSIV infectivity in various cell lines indicated that the GSIV could reproduce in EPC,CCK,RTG-2 cells,but the reproducing speed was faster in EPC and CCK,and TCID50 was higher,and the optimum the optimum temperature was 25 ℃ in EPC cells.The results of GSIV replication dynamics in EPC cells demonstrated that viral titer began to rise at 6 h post infection and then increased logarithmically,at 72 h post infection,the viral titer reached the highest and then leveled off.Electron microscopy observation of ultrathin sections of GSIV infected EPC cells revealed that there were numerous iridovirus-like particles with a diameter of about 140 nm arrayed in crystalline in the cytoplasm.