Cytoplasmic Polyhedrosis Viruses

W2 Virus Infection of the Crustacean Carcinus mediterraneus: a Reovirus Disease

“…Virus morphogenesis occurs in small dense areas scattered in the cytoplasm; we interpret these as viroplasms. The virogenesis reported in the case of P virus of M. depurator (Bonami, 1980) was similar to this, but unlike the morphogenesis observed in cytoplasmic virosis of the scorpion Buthus occitanus (Morel, 1975(Morel, , 1979, Fijivirus (Boccardo et al, 1980) or cytoplasmic polyhedrosis virus (Xeros, 1956;Bird, 1965;Payne & Mertens, 1983).…”

“…The capsid structure of the W2 virus strongly resembles the capsomer arrangement of some members of the Reovirus (Smith et al, 1969;Wood, 1973;Joklik, 1983), Rotavirus (Palmer et al, 1977;Esparza & Gil, 1978;Holmes, 1983) and Orbivirus genera (Wood, 1973). However, we have not observed structures resembling the spikes described in cytoplasmic polyhedrosis virus and on the cores of Reovirus (Hosaka & Aizawa, 1964;Joklik, 1974;Payne & Harrap, 1977;Joklik, 1983) or the A and B spikes of Fijivirus (Boccardo et al, 1980). Virus morphogenesis occurs in small dense areas scattered in the cytoplasm; we interpret these as viroplasms.…”

“…However, an original aspect of infections with W2 virus, and which has not been reported in previous viral infections of crabs, is the presence of electron-dense material sometimes containing tubular formations and virions. These did not exhibit an organized structure and did not seem to be similar to the paracrystalline inclusion bodies of the type described in insect cytoplasmic polyhedrosis infections (Bird, 1965;Vago & Bergoin, 1968;Payne & Mertens, 1983). On negative staining of purified particles, a double-shelled capsid was observed; such a feature, characteristic of several but not all genera of the Reoviridae (Matthews, 1982), has also been observed in W virions (J. R. Bonami & B. J. Hill, unpublished observations) and P virions (Bonami, 1977(Bonami, , 1980 of Crustacea.…”

“…The possible existence of one or more double bands made of two segments of the same Mr cannot be discounted ; therefore more accurate detection techniques such as electrophoresis in 7.5 or 10~ polyacrylamide should be considered (Payne & Mertens, 1983). The presence of nine segments does not constitute a fundamental difference from established members of the Reoviridae; because some members of this family (as yet unclassified within a genus), possess a genome containing only eight segments (Matthews, 1982).…”

Genome segment 4 of Antheraea mylitta cytoplasmic polyhedrosis virus encodes RNA triphosphatase and methyltransferases

“…Cypovirus of the family Reovirodae (Mertens et al, 2005) and contains 10 segments of dsRNA (Payne & Mertens, 1983). Each dsRNA segment is composed of a plus strand and its complementary minus strand in an end-to-end base pair configuration except for a protruding 59-capped end (Furuichi & Miura, 1975).…”