Ultrastructural morphogenesis of a virus associated with lymphocystis-like lesions in parore Girella tricuspidata (Kyphosidae: Perciformes).
The morphogenesis of large icosahedral viruses associated with lymphocystis-like lesions in the skin of parore Girella tricuspidata is described. The electron-lucent perinuclear viromatrix comprised putative DNA with open capsids at the periphery, very large arrays of smooth endoplasmic reticulum (sER), much of it with a reticulated appearance (rsER) or occurring as rows of vesicles. Lysosomes, degenerating mitochondria and virions in various stages of assembly, and paracrystalline arrays were also present. Long electron-dense inclusions (EDIs) with 15 nm repeating units split terminally and curled to form tubular structures internalising the 15 nm repeating structures. These tubular structures appeared to form the virion capsids. Large parallel arrays of sER sometimes alternated with aligned arrays of crinkled cisternae along which passed a uniformly wide (20 nm) thread-like structure. Strings of small vesicles near open capsids may also have been involved in formation of an inner lipid layer. Granules with a fine fibrillar appearance also occurred in the viromatrix, and from the presence of a halo around mature virions it appeared that the fibrils may form a layer around the capsid. The general features of virogenesis of large icosahedral dsDNA viruses, the large amount of ER, particularly rsER and the EDIs, are features of nucleo-cytoplasmic large DNA viruses, rather than features of 1 genus or family.
National Centre for Disease Investigation, MAF Operations, Ministry of Agriculture and Forestry, PO Box 40-742, Upper Hutt, New Zealand.
P M
PM
Hine
St J
SJ
Wakefield
G
G
Mackereth
R
R
Morrison
D000818:Animals; D004266:DNA Virus Infections / Q000662:veterinary* / Q000821:virology; D004267:DNA Viruses / Q000302:isolation & purification*; D005393:Fish Diseases / Q000473:pathology / Q000821:virology*; D010473:Perciformes