文山松毛虫质型多角体病毒形态结构及理化性质的研究

Studies on Fine Structure and Some Physico--chemical Characteristics of a Cytoplasmic Polyhedrosis Virus from Dendrolimus punctatus Wenshanensis

对文山松毛虫质型多角体病毒的形态结构及理化特性进行了研究,多角体大部分为六边形,少数为四边形及近园形,其大小在0.47～2.45μ之间,平均为1.1μ。病毒粒子呈球形,无囊膜,致密的核芯区由一层外壳包裹,直径为60nm。病毒粒子表面有12个刺突,放大图象可见其亚单位排列。多角体蛋白的主要成分为一种,分子量为26200道尔顿,多角体蛋白氨基酸组成中不含半胱氨酸;其碱性氨基酸与酸性氨基酸之比为1:2.16。病毒粒子结构蛋白含五条多肽组分。用SDS-热酚法提取所得核酸,其热变性紫外吸收OD260值增加51.6％。抗核酸酶S1。Tm值为86℃。在1％琼脂糖凝胶电泳中可分为9个片段,而在5％PAGE中,则可分为10个片段。各片段大小在0.66×106～2.85×106道尔顿之间,总分子量为15.35×106。电镜分析研究显示了CPV RNA在0.4μ、0.8μ和1.2μ处有三个分布峰。

A Cytoplasmic polyhedrosis virus (CPV) from the Dendrolimus punctatusWenshanensis was studied on some characterizations of fine structure and bio-chemistry. Most of polyhedra were hexhedral, less quadrilaterly and appro-ximaterly spherical. The size of polyhedra showed a significant differenceranging from 0.47 to 2.45μ and 1.1μ in average in diameter. Virions werespherical in shape with six spikes Iocated and icosahedral vertices, measuring60nm in diameter. Magnifying the photograph, the subunit arrangement of vi-rion was observed, and dense core area is surrounded by an out-shell, but noclearly defined outer capsid structure like that of Reovirus and no envelope.The major polyhedral protein had a mol. wt. of approx. 26200 daltons. No cy-stein is found in the polyhedral protien analysis, and the ratio of basic aminoacid to acidic amino acid was 1: 2. 16. M. W. of five structural polypeptidesof virus ranging from 23--114.5k daltons were detected in SDS-PAGE. TheCPV RNA was extracted from purified polyhedra using hot phenel-SDS method.Thermal denaturation resulted in a marked increase by 51.6% in hyperchromicity. The RNA was resistant to nuclease S_1 and Tm of 89℃. The genomeconsisted of nine (in 1% agarose) or ten(in 5% PAGE) RNA segments, themol.wt.range of which is 0.66×10~6～2.85×10~6 daltons with a total of 15.35×10~6 daltons. Three distribution peaks of centour length of the RNA semen-to were found at 0.4μ, 0.8μ 2nd 1.2μ, respectively.