Epizootic haematopoietic necrosis virus: purification and classification

Abstract

Abstract. Epizootic haematopoietic necrosis virus (EHNV) has been isolated from redfin perch, Perca fluviatilis L., and cultured rainbow trout, Oncorhynchus mykiss (Walbaum), in Victoria and New South Wales, Australia. On the basis of virion size, icosahedral morphology and ultrastructural characteristics of virus‐infected cells, EHNV was designated as an iridovirus. The following observations outlined in this paper confirm the designation: (1) The number and complexity of proteins in purified EHNV and the ordered appearance of virus‐specific proteins in infected cells are similar to that described for the iridovirus, frog virus 3 (FV3). (2) EHNV isolated from the cytoplasm of infected cells contains a lipid membrane associated with 7–9 nm capsomeric subunits containing a 52‐kD protein. (3) The morphogenesis of EHNV within cytoplasmic inclusion bodies resembles that of FV3 and a piscine iridovirus isolated from goldfish, Carassius auratus (L.) (4) EHNV also resembles FV3 in its association with the cytoskeleton of infected cells. (5) EHNV DNA, like that of other iridoviruses, is resistant to digestion with HpaII, a restriction endonuclease which does not cleave DNA at CCGG sequences where the internal cytosine is methylated.

An iridovirus-like agent isolated from the ornate burrowing frog Limnodynastes ornatus in northern Australia

“…The morphologies of EHNV and our isolate are similar and they cause a similar CPE. Like our isolate and the ranaviruses, EHNV also has methylated DNA (Eaton et al 1991). The only biological difference noted is higher titres at lower temperatures with EHNV, while our isolate replicates equally well at 20 to 30 "C. Although our isolate and EHNV can not be distingulshed on published data, there are no reports of attempted infections of mammalian or insect cells with EHNV.…”

“…Epizootic haematopoietic necrosis virus (EHNV) was isolated from redfin perch Perca fluviatilis (Langdon et al 1986, Langdon & Humphrey 1987 and an EHNV-like agent was isolated from rainbow trout Salmo gairdneri (Langdon et al 1988), but further study is required to determine the degree of similarity between the 2 isolates (Eaton et al 1991). The morphologies of EHNV and our isolate are similar and they cause a similar CPE.…”

Electron microscopic examination of the viromatrix of Rana grylio virus in a fish cell line

“…Viral components concentrate in the viromatrix, thereby increasing the efficiency of the processes (Murti and Goorha, 1983;Eaton et al, 1991;Zhang et al, 1999;Qin et al, 2001). The formation of the viromatrix involves Note: the viromatrix was observed from 6 h p.i., so the data of 2 h and 4 h were zero.…”

“…The family iridoviridae, which is divided into four genera Ranavirus, Lymphocystivirus, Iridovirus and Chloriridovirus, is also large (120-350 nm) DNA-containing viruses (Just and Essbauer, 2001;Tordo et al, 2004), but the viromatrix of Ranavirus has not been described in detail (Murti and Goorha, 1983;Eaton et al, 1991). In the present study, electron microscopic investigations were carried out on the ultrastructure of viromatrix of RGV in infected epithelipma papulosum cyprini (EPC) cells and relationship between the viromatrix and some cellular components.…”

“…Following infection with FV3, the type species of the genus Ranavirus, the structural integrity of viromatrix is maintained by reorganized IFs (7-11 nm in diameter) (Murti and Goorha, 1983). In epizootic haematopoietic necrosis virus (EHNV)-infected cells and VV-infected cells, IFs were also observed around the viromatrix or viral factory (Eaton et al, 1991;Risco et al, 2002).…”