黄地老虎核型多角体病毒的一些特性

SOME PROPERTIES OF AGROTIS SEGETUM NUCLEAR POLYHEDROSIS VIRUS

黄地老虎核型多角体病毒(Agrotis segetum Nulear Polyhedrosis Virus简称AsNPV)的国内分离株(AsNPV^C),多角体呈六边形,大小1.7—2.6μm,为多粒包埋类型。每个病毒束内有2—7个核衣壳,大小约52nm×308nm。感染烟青虫(Heliothis assttlta)后分离到的多角体(As-HaNPV)其形状不规则,大小0.7—2.6μm,亦为多粒包埋类型。核衣壳2—6个不等,大小约40nm×300nm。EcoR1和HindⅢ限制性内切酶电泳图谱分析表明,AsNPV^CDNA和As-HaNPV DNA的EcoRI、HindIII酶切图谱一致,两者与HaNPV DNA的EcoRI,HindⅢ酶切图谱存在明显差异,AsNPV^C DNA的EcoRI酶切图谱共有15个片段,分子量在12.74×10~6—1.18×10~6道尔顿之间,总分子量约88.6×10~6道尔顿,相当于134.25kbp。HaNPV DNA的EcoRI酶切图谱共有19个片段,分子量在13.89×10~6—1.10×10~6道尔顿之间,总分子量约93.86×10~6道尔顿,相当于142.25kbp。AsNPV对黄地老虎2龄和4龄幼虫以及对烟青虫4龄幼虫的LD_(50)分别为:1.4×10~5pIB、7.4×10~4PIB和2.61×10~4PIB。

Agrotis segetum nuclear polyhedrosis virus (AsNPV) isolated from the yellow cutworm larvae in Beijing is multiple-enveloped. The morpha and size of the polyhededral bodies and virus particles from A. segetum and Heliothis assulta infected with AsNPV (As-HaNPV) were observed with electron microscope. The electrophoretic profiles of DNA restriction en doclease fragments appeared to be identical in AsNPV and As-HaNPV, but they were different from that of HaNPV. The molecular weight of AsNPV-DNA EcoRI-digested fragments added up to be about 88.6×106 dalton (134.25 kbp). The comparative virulence of the virus in original host and alternative host was examined by measuring their median lethal concen-rations (LC50) and median lethal time (LT50) in different instar larvae. The biochemical specificity and infectivity to A. segetum and alternative hosts of Chinese isolate of NPV from A. segetum have been compared with those of three European isolates (Allaway, et al. 1983)