我国蚊虫分离的一种新型胞质多形体病毒

New Type of Cytoplasmic Polyhedrosis Virus Isolated from Mosquitoes in China

0507BS3是从中国新疆喀什地区采集的库蚊和按蚊混合蚊标本分离的病毒株,对C6/36细胞致病变而对Ve-ro和BHK-21细胞不致病变。电镜观察显示病毒颗粒呈圆球形,直径约60nm(n=20),无包膜,单层衣壳,衣壳内有中央核。基因组核酸电泳显示基因组包括10条双链RNA(double stranded RNA,dsRNA)片段。病毒第10基因片段核酸序列测定显示该片段全长964bp(GenBankID:FJ150869),具有单一开放读码框,编码长度为275个氨基酸的蛋白,分子量约30.8kD。病毒第10基因片段核酸序列比对未发现相似的病毒核酸序列,氨基酸序列与胞质多形体病毒(Cytoplasmic polyhedrosis virus,CPV)第10基因片段编码的多形体蛋白部分区段匹配。病毒第10基因片段和已知各型CPV第10基因片段核酸序列共同进行系统进化分析显示该病毒位于独立的进化分枝,提示0507BS3病毒可能是一种新型CPV病毒。

0507BS3 virus was isolated from a mixed pool of Culex sp. and Anopheles sp. collected in Kashi, Xinjiang, China. 0507BS3 virus could cause cytopathic effects on C6/36 cells but not on Vero and BHK-21 cells. Viral particles had no envelope and appeared round with diameter of about 60nm （n=20）. Viral capsid was composed of a single layer and a central core. Capsomeres on the surface of capsid were clearly visible. Electrophoresis of viral genome showed a profile of 10 double stranded RNA （dsRNA） segments. Sequencing of the tenth segment revealed the length of 964bp （GenBank ID. FJ150869）. A single open reading frame （ORF） was found and encoded a protein of 275 amino acids with a molecular mass of 30. 8kDa. The nucleotide sequence had no similarity with any other viral genomic sequences, but the deduced amino acid sequence significantly matched the polyhedrin genes of cytoplasmic polyhedrosis virus （CPV） in some sections. A phylogenetic tree was constructed to compare the polyhedrin gene sequences of all CPV types in GenBank. The tree demonstrated that 0507BS3 virus was only distantly related to the other CPV types and belonged to a new CPV type.