家蚕浓核症病毒感染昆虫细胞系的电镜观察

Electromicroscopic Observation of Bombyx mori Densonucleosis Virus Infecting Insect Cell Lines

本实验首次用中国株家蚕浓核症病毒感染三株昆虫细胞系:油桐尺蠖卵巢细胞系(BS-484)、甘兰夜蛾卵巢细胞系(NIAS—MB—19)和秋粘虫卵巢细胞系(IPLB—SF—21)。结果仅在BS—484细胞中观察到病毒感染引起的细胞病变效应。电镜观察发现在感染的BS—484中,细胞核明显膨大,其中核仁活性化,数目增多,同时还观察到核仁膨大和分裂现象。感染5—6天,可看到成熟病毒粒子于核内形成。在感染的细胞质中,线粒体肥大且失去脊,粗面内质网变成小泡体,其内积累大量核糖核蛋白体。许多细胞器空泡化或退化,细胞质中出现一些包含退化细胞器的大型自身吞噬体。

There have not been formally reports of Bombyx mori densonucleosis virus infccting insect cell lines. In the present paper three insect overy cells of B.suppressaria, S. frugiperda and M.brassicae infected with Bombyx mori densonucleosis virus.The result is that cytopathic effect was only observed in the overy cells of B.suppressaria. The ultrastructural changes of the infected cells have been observed both in the cytoplasm and nucleus. At an early stage of infection, the infected nucleus hypertrophied gradually,and many nucleoli appeared as the progress of infection. The nucleus hypertrophied greatly.Then two differnt patterns of infected nucleus were found. In the first pattern,virions were replicated in crystal arrays in virogenic stroma. In the second pattern, replicated virions were dispersed as patches and gradually condense and finally became large masses of virion. The nuclear membrane ruptured and viral masses were released into the cytoplasm. In the cytoplasm of infected cell, rough endoplasmic reticula became vesicles or cisternae in which a large nember of ribosome first appeared. With replication of the virions, organelles, such as mitochondria and endoplasmic reticula, vacuolated and degenerated. At the same time, many lysosomes appeared and some large autophagosomes containing the degenerated organlles occured.