Replication Of Frog Iridovirus (RGV) And The Changes Of Cytoskeleton, Ultrastructural Organelles In The Host Cells

Rana grylio virus (RGV), a ranavirus belonging to the family Iridoviridae, was isolated from the diseased Rana grylio in China. Ultrastructural observations showed that RGV assembles in the viromatrix which is a factory for viral genome replication and particle assembly. Our works focused on replication of frog RGV and the changes of cytoskeleton and ultrastructural organelles in the host cells by a series of technique methods, such as electron microscopic observation, immunofluorescent microscopic observation, and flow cytometry. The results are given as follows:1. The ultrastructures of the viromatrix and their quantitative changes in RGV infected epithelipma papulosum cyprini (EPC) cells were studied at different infection times by electron microscopy. Viromatrix were observed in the proximity of the nuclear at 6h postinfection (p.i.), and their electron density was lower than that of the surrounding cytoplasm. The viromatrix contained viral assembly intermediates with different forms and amorphous structures which included tubules and membranous materials. Tubules with 110-124nm diameter were often observed in direct continuity with empty capsids. The membranous material was composed of three layers membranes, and some were associated with the assembly intermediates. In addition, dense floccule materials and tubules (40-50nm in diameter) were also observed in the viromatrix.A total of 990 cells profiles were examined for quantitative analyses of the viromatrix. The results showed that 394 cells contained viromatrix: 89.3% contained one, and 10.7% contained two to four viromatrix. The number of viromatrix increased gradually and reached a peak at 16h p.i. The viromatrix area at 24h p.i increased up to 7.4±0.69μm2 which...