柳天蚕蛾多粒包埋核型多角体病毒的研究

Studies on the Actias selene Multiple-enveloped Nuclear Bolyhedrasis Virus

本文报道柳天蚕蛾多粒包埋核型多角体病毒的分离,形态特征,组织病理及其生物活性研究。1985年10月从昆明大观楼柳树上采集的柳天蚕蛾自然罹病幼虫体中分离到一种多粒包埋(MEV)核型多角体病毒(NPV)。多角体呈不规则的多角形,大小不等,直径约为2.013±0.138μm。多角体在宿主细胞核内形成。病毒粒子在多角体内除少数为单粒包埋外,多数以2～15个核衣壳包埋成束,病毒束直径约为271.43±121.43nm,经弱碱处理而游离的病毒核衣壳杆状,微弯曲,两端钝圆,大小为433.34±33.34×77.5nm。属杆状病毒科(Baculoviridae),杆状病毒属(Entomopoxvirus),A亚群(Subgroup A)一种。缩写AsMNPV。用2-2000PIB/ml AsMNPV感染柳天蚕蛾3龄单个幼虫,7天后死亡率为28.2～98.0％,LC_(50)为6.82PIB/ml。用9.6-9.6×10~7PIB/ml感3龄群体幼虫,7天后死亡率为29.52～100％,LC_(50)为7.0896×10~1PIB/ml。用9.6×10~7PIB/ml分别感染1～4龄幼虫,9天后备龄幼虫死亡率分别为97％、95％、90％和70％。生物测定结果表明AsMNPV对柳天蚕蛾幼虫有很高的致死率,其幼虫对AsMNPV的敏感性,随虫龄的增大而递减。

The present paper presents with the results of the studies on the morphological characterization, pathological response of tissues and biological activity of Actias selene multiple-enveloped nuclear polyhedrosis virus ( AsMNPV) with the susceptibility of different insars larvae to homologous hosts. A multiple-enveloped nuclear polyhedrosis virus was isolated from diseased Actias selene at Daguanlou, Kunming in October 1985. The polyhedrons virus irregular polygons of variable size with a mean dimeter of 2.013±0.138 μm. A few nicleocapsids were singly embedded. Usually, 1-15 nucleocapsids aggregated to form bundles, the range of diameters being. When dissociated with weak alkali, virions were found to be of two distinct forms: the one being slightly curved rods the size being 433.34±33.34×77.5 nm. With blunt ends, the other being rectangular in profile, the mean size being 337.08±0.42×195.32±4.69 nm. When Actias selene third-instar larvae were infected by 9.6-9.6×107 PIB/ ml AsMNPV, 7 days postinfection the mortality was 29.52-100%, and LC50 was 7.0896×10 PIB/ ml, when the larvae were individually infected by virus-trented willow leaves with 2-2000 PIB / ml for 7 days, postinfection, the mortality was 28. 2-98%, and LC50 was 6. 82 PIB/ ml. When the 1st-, 2nd-, 3rd- and 4th-instar larvae were infected be 9. 6×106PIB / ml, 9 days post infection the respective mortality were 97%, 95%, 90% and 70%, and the respective LT50 were 5.19, 6.21, 7.02 and 8.07 days. These results indicated that AsMNPV was highly virulent to Astias selens larvae and the saseeptibility of the larvae to AsMNPV decreased with the increase of larvae age. However, as soon as the first larvae death had occurred, the daily mortality of older larvae became lower than that of the younger.