[pathogenesis of the toxic hepatitis of mice provoked by fv 3 (frog virus 3): inhibition of liver macromolecular synthesis (author's transl)]. 19734733696
preparation and properties of an inhibitory extract from frog virus 3 particles.the structural constituents of the frog virus 3 particle were solubilized by treatment with a nonionic detergent followed by the addition of a high salt concentration. this soluble viral extract (sve) inhibits host nucleic acid synthesis. its activity on rna synthesis was studied in kb cells and found to be dependent on the presence of deae dextran. inactivation of the inhibitory properties of sve were obtained by trypsin digestion, treatment with urea, or heat denaturation. neutralization of th ...19734736109
thymidine kinase induction in frog virus 3 infected mouse cells. 19744821695
rna synthesis in cells infected with an icosahedral cytoplasmic deoxyvirus (frog virus 3).in cells infected with frog virus 3 there was extensive but not complete inhibition of host rna synthesis. host rna processing was not impaired. the electrophoretic pattern of frog virus 3 specific rna transcripts in infected fhm cells has been determined. when analyzed by gel electrophoresis, the transcripts separated in a size range of 6 to 16s with the bulk migrating around 16s. these rna's contain polyadenylic acid stretches of approximately 150 to 200 nucleotides. in the absence of viral dn ...19744824712
inhibition of dna synthesis by isolated liver nuclei from frog virus 3 infected mice. 19744827833
effect of non-permissive temperature on the assembly of frog virus 3 particles. 19744836909
macromolecular synthesis in cells infected by frog virus 3. ii. evidence for post-transcriptional control of a viral structural protein. 19744841177
frog virus 3 deoxyribonucleic acid. 19744852099
immunization of mice against the toxic hepatitis produced by fv3: inhibition of virus penetration into the liver. 19744852356
replication of influenza virus in chick embryo fibroblasts after inhibition of host cell macromolecular synthesis by frog virus 3. 19744856572
viruses and renal carcinoma of rana pipiens. iv. nucleic acid synthesis in frog virus 3-infected bhk 21/13 cells. 19674964866
viruses and renal carcinoma of rana pipiens. v. effect of frog virus 3 on developing frog embryos and larvae. 19684966291
induction and regulation of dna nucleotidyltransferase activity in fish cells infected with frog virus 3. 19694975945
[inhibition of synthesis of cellular dna and rna in kb cells infected by virus 3 of frog (fv3)]. 19704987655
[inhibition of production and intiviral action of chicken interferon by frog 3 virus (fv3)]. 19704991497
[action of frog virus 3 (fv3) on the synthesis of rna by sindbis virus]. 19714995280
[lethality for mice of the frog virus 3 (fv3)]. 19714997102
[fv3 (frog virus 3) toxicity for the mouse]. 19725053604
photoreactivation of a cytoplasmic virus.ultraviolet light-inactivated frog virus 3 is efficiently photoreactivated by chick embryo cells. a cellular enzyme is presumably responsible for this repair of viral deoxyribonucleic acid, for the phenomenon is insensitive to an inhibitor of protein synthesis and is not seen in mammalian cells that are known to lack photoreactivating enzyme. since frog virus 3 is a cytoplasmic virus, functionally significant amounts of photoreactivating enzyme are probably present in the cytoplasm of chick embr ...19725062749
viruses and renal carcinoma of rana pipiens. xi. isolation of frog virus 3 temperature-sensitive mutants; complementation and genetic recombination. 19715105771
inhibition of host-specific dna and rna synthesis in kb cells following infection with frog virus 3. 19715165854
inhibition by frog virus 3 of vaccinia virus and host cell dna replication in kb cells. 19695362662
[radioautographic study of the development of the virus 3 of the frog (fv3) on renal cells of calf fetus]. 19705461275
the inhibition of vaccinia virus dna synthesis in kb cells infected with frog virus 3. 19705477329
restricted replication of frog virus 3 in selected variants of bhk cells.synthesis and maturation of frog virus 3 deoxyribonucleic acid (dna) in bhk cells and selected variants, in chick fibroblasts, and in minnow cells were compared. wide ranges in rates of dna synthesis and assembly of virions were found. at least three variants of bhk cells can be obtained: (i) fully permissive, characterized by rapid dna synthesis and assembly to give a high yield of infective virus; (ii) semipermissive, in which viral dna is synthesized slowly for extended periods of time, and t ...19705488804
viruses and renal carcinoma of rana pipiens. vi. interrelationships of macromolecular synthesis and infectious virus production in frog virus 3-infected bhk 21/13 cells. 19685643637
deoxyribonucleic acid synthesis in fv-3-infected mammalian cells.deoxyribonucleic acid (dna) synthesis and virus growth in frog virus 3 (fv-3)-infected mammalian cells in suspension were examined. the kinetics of thymidine incorporation into dna was followed by fractionating infected cells. the cell fractionation procedure separated replicating viral dna from matured virus. incorporation of isotope into the nuclear fraction was depressed 2 to 3 hr postinfection; this inhibition did not require protein synthesis. about 3 to 4 hr postinfection, there was an inc ...19685749374
nucleotide sequence of an immediate-early frog virus 3 gene.we have used "gene walking" with synthetic oligonucleotides and m13 dideoxynucleotide sequencing techniques to obtain the complete coding and flanking sequences of the gene encoding a major immediate-early rna (molecular weight, 169,000) of frog virus 3. r-loop mapping of the cloned xbai k fragment of frog virus 3 dna with immediate-early rna from infected cells showed that an rna of approximately 500 to 600 nucleotides (the right size to code for the immediate-early viral 18-kilodalton protein ...19846092719
kupffer and endothelial liver cell damage renders a/j mice susceptible to mouse hepatitis virus type 3.damage to the kupffer and endothelial cells of the liver sinusoids induced by the administration of sublethal doses of frog virus 3 (fv 3) renders a/j mice which are genetically resistant to mouse hepatitis virus type 3 (mhv 3) highly susceptible to this virus. liver histopathology of these animals revealed typical necrotic foci containing mhv 3-specific antigens. fv 3-pretreated mice, after mhv 3 infection, showed higher levels of serum transaminase (gpt) than controls, and mhv 3 replicated mor ...19846099940
inhibition of erythrophagocytosis by cultured rat kupffer cells infected with frog virus 3. 19806159473
frog virus 3 induces a fatal hepatitis in define its pathogenesis, the acute degenerative hepatitis caused by frog virus 3 (fv3) has been reproduced in the rat, thus facilitating a greater number of biologic explorations than in the mouse. the histologic and ultrastructural study proves a massive hepatocellular necrosis perfectly compatible with the fatal outcome of the illness 30 hours after the inoculation of one ld100. critical analysis of the fv3 rat hepatitis induces us to advance three arguments for excluding the direct role of ...19816168820
murine hepatitis induced by frog virus 3: a model for studying the effect of sinusoidal cell damage on the liver. 19836185407
the role of dna methylation in virus replication: inhibition of frog virus 3 replication by 5-azacytidine.frog virus 3 (fv3) dna is the most highly methylated dna of any known dna virus; about 20% of the cytosine residues in fv3 dna are methylated (d. willis and a. granoff, 1980, virology 107, 250-257). to understand the role of dna methylation in virus replication, we have examined the effect of 5-azacytidine, a drug that inhibits dna methylation. 5-azacytidine (10 microm) reduced the production of infectious fv3 by 100-fold or more and inhibited methylation of viral dna by about 80%. inhibition of ...19846208681
frog virus 3 dna is heavily methylated at cpg sequences. 19806255678
restriction endonuclease mapping of the frog virus 3 genome.a physical map for the frog virus 3 (fv 3) genome was constructed after digestion with the following restriction endonucleases: ecori, hindiii, kpni, and xbai. mapping of the dna was accomplished by partial digestion and recutting, double-digestion, and southern blot hybridization with deduction of overlaps. although the virion dna is physically linear, the restriction map was circular, supporting the data that the fv 3 genome is circularly permuted (goorha and murti, proc. nat. acad. sci usa 79 ...19836302988
interaction of frog virus-3 with the cytoskeleton. i. altered organization of microtubules, intermediate filaments, and microfilaments.the progressive cytoskeletal alterations of frog virus 3-infected baby hamster kidney (bhk) and fathead minnow (fhm) cells were studied by immunofluorescence and electron microscopy. the virus assembly sites, which contain viral genomes and viral proteins, were detected in the cytoplasm at 4 h (fhm) or 6 h (bhk) and mature virions appeared 2 h later. when infected cells were treated with triton x-100, the assembly sites were found in association with the cytoskeleton. in infected cells, the numb ...19836341377
early proteins are required for the formation of frog virus 3 assembly sites.the formation of frog virus 3 virions takes place within morphologically distinct regions of the cytoplasm termed assembly sites. these sites are formed within infected bhk cells by 6-7 hr after infection, a time when viral dna and both early and late proteins are present. to identify macromolecules involved in assembly site formation, a temperature-sensitive mutant ( ts9467 ) was used which is not only defective in the synthesis of late rna and proteins (d.b. willis, r. goorha , and a. granoff ...19846375119
frog virus 3: a dna virus with an unusual life-style. 19846379750
localization of frog virus 3 proteins using monoclonal antibodies.thirty-seven monoclonal antibodies to seven frog virus 3 (fv3) structural proteins were isolated and used to examine the distribution of viral proteins within virions and infected cells. three monoclonal antibodies, one to the major capsid protein, vp55, and two to vp38 had detectable neutralizing activity suggesting that these proteins are located on the surface of virions. immunofluorescent studies showed that vp108, vp57, vp55, and vp16 were localized mainly within virus assembly sites, while ...19846382789
ultrasonic absorption evidence for structural fluctuations in frog virus 3 and its subparticles.the structural fluctuations specific to self-assemblies of biological molecules have been investigated further with ultrasonic techniques by using frog virus 3 (fv3). we compared the ultrasonic properties of complete fv3 virions and of several subparticles that may be obtained from this dna virus: (i) the central nucleoprotein core versus its component dna and proteins in a dissociated state; (ii) the core versus the capsidless subparticle, consisting of the core surrounded by the lipid membrane ...19836408639
viricidal effects of lactobacillus and yeast fermentation.the survival of selected viruses in lactobacillus- and yeast-fermented edible waste material was studied to determine the feasibility of using this material as a livestock feed ingredient. five viruses, including newcastle disease virus, infectious canine hepatitis virus, a porcine picornavirus, frog virus 3, and bovine virus diarrhea, were inoculated into a mixture of ground food waste (collected from a school lunch program) containing lactobacillus acidophilus. mixtures were incubated at 20, 3 ...19836414372
isolation and characterization of a frog virus 3 variant resistant to phosphonoacetate: genetic evidence for a virus-specific dna polymerase.a variant of frog virus 3 (fv3) resistant to 200 micrograms/ml phosphonoacetate was isolated, and used to establish that the dna polymerase induced in fv3-infected cells was virus coded. in addition, inhibitor studies showed that the fv3 polymerase is similar to eukaryotic polymerase alpha in its sensitivity to aphidicolin, and that resistance to phosphonoacetate does not confer cross-resistance to thymidine arabinoside or acycloguanosine.19846437076
interaction of frog virus 3 with the cytomatrix. ii. structure and composition of the virus assembly site.we have described the structure of virus assembly sites in frog virus 3-infected tissue culture cells based on an examination of sectioned and whole cells by conventional and high voltage (1 000 kv) electron microscopy (hvem), respectively. we have also attempted to identify the cellular and viral components within the assembly sites using immunofluorescence and a combination of dnase digestion and em autoradiography. immunofluorescence studies showed that the sites do not contain tubulin, vimen ...19846468528
the organization of frog virus 3 as revealed by freeze-etching.a variety of freeze-fracture techniques has been employed in this study with the aim of dissecting the frog virus 3 virion and obtaining further information about its architecture. the icosahedral capsid has a skew symmetry with a triangulation number of 133 or 147. the capsomers are closely packed with a center-to-center spacing of 72 a. the inner membrane contains transmembrane proteins which appear as intra-membranous particles on both fracture faces. rod-like structures (about 100 a in diame ...19846495651
dna methyltransferase induced by frog virus 3.over 20% of the cytosine bases in frog virus 3 dna are methylated at the 5-carbon position. to determine whether this high degree of methylation is the result of a virus-specific enzyme, we examined the kinetics of induction and the substrate specificity of a dna methyltransferase from frog virus 3-infected fathead minnow cells. a novel dna methyltransferase activity appeared in the cytoplasm of infected cells at 3 h postinfection. this activity was induced in the absence of viral dna replicatio ...19846690723
fate of frog virus 3 dna replicated in the nucleus of arginine-deprived cho a productive infection, frog virus 3 (fv 3) dna was synthesized in both the cell nucleus and cytoplasm. the infection was aborted in arginine-starved chinese hamster ovary cells and viral dna replication was then restricted to the nuclear compartment. it has been demonstrated that the newly synthesized fv 3 dna present in the nucleus is of genomic size. after the addition of arginine, this dna is transferred into the cytoplasm and can be encapsidated. the formation of infectious particles occ ...19846707611
probable role of endogenous endotoxins in hepatocytolysis during murine hepatitis caused by frog virus 3.three new observations bear out the role of endogenous endotoxins in the pathogenesis of murine hepatitis caused by frog virus 3. first, the ld50 of endotoxin is 20 times lower in mice pretreated for 2.5 hr with a sublethal dose of frog virus 3 than in untreated mice. animals inoculated with one sublethal dose of lipopolysaccharide 2.5 hr after injection of one sublethal dose of virus die, all having developed extensive hepatocellular necrosis. this hypersensitivity varies according to the inten ...19846725994
a temperature-sensitive (ts) mutant of frog virus 3 (fv3) is defective in second-stage dna has been suggested that fv3 dna replication occurs in two stages [r. goorha (1982) j. virol. 43, 519-528]. first-stage dna synthesis is restricted to the nucleus, where the replicating dna ranges from genome to twice genome size; second-stage dna replication occurs exclusively in the cytoplasm, and the replicating dna is concatameric. a temperature-sensitive mutant (ts 12488) of fv3, at a nonpermissive temperature (30 degrees), synthesized dna in the nucleus only, and the size of the replicat ...19846740949
cell-free translation of frog virus 3 messenger rnas. initiation factors from infected cells discriminate between early and late viral mrnas.cell-free protein-synthesizing extracts prepared from rabbit reticulocytes, wheat germ, or cultured baby hamster kidney cells efficiently translated frog virus 3 early mrnas; in contrast, late mrnas were translated poorly under similar conditions. however, the translational efficiency of the late viral mrnas was markedly enhanced in cell-free extracts prepared from frog virus 3 (fv 3)-infected baby hamster kidney cells and in nuclease-treated rabbit reticulocyte extracts by the addition of a 0.5 ...19836848520
dna-binding proteins in frog virus 3-infected least 12 virus-induced dna-binding proteins with mol. wt. ranging from 14 x 10(3) have been isolated from frog virus (fv 3)-infected fathead minnow cells by dna affinity chromatography. two enzymic activities, dna-dependent dna polymerase and endodeoxyribonuclease, were present in the dna-binding proteins; these enzymic activities were similar to those induced by fv 3 in infected cells. a single species of dna-binding proteins with a mol. wt of 36 000 had very high affinity for single-strande ...19816895383
the genome of frog virus 3, an animal dna virus, is circularly permuted and terminally redundant.we examined the structure of the frog virus 3 (fv 3) genome by using electron microscopic and biochemical techniques. the linear fv 3 dna molecules (mr approximately 100 x 10(6) formed circles when partially degraded with bacteriophage lambda 5'-exonuclease and annealed, but not when the annealing was done without prior exonuclease digestion. the results suggest that the dna molecules contain direct terminal repeats. the repeated region composed about 4% of the genome. complete denaturation of n ...19826952182
localization of some frog virus 3 structural polypeptides. 19826977935
structure of frog virus 3 genome: size and arrangement of nucleotide sequences as determined by electron microscopy. 19827064341
localization by autoradiography of viral proteins in the parenchymal cells of the liver during frog virus 3 induced hepatitis of mice.frog virus 3 inoculated into mice induces an acute degenerative hepatitis. this hepatitis is of toxic origin since the virus is unable to multiply at 37 degrees c. the kupffer cells, which are the target cells for fv3, reveal the presence of viral particles, viral dna and proteins. although the hepatocytes present early and drastic nuclear lesions, viral particles were never observed in these cells. viral proteins however but not dna, could be found inside parenchymal cells.19827108998
frog virus 3 dna replication occurs in two stages.viral dna synthesis in frog virus 3 (fv3)-infected cells occurs both in the nucleus and in the cytoplasm (goorha et al., virology 84:32-51, 1978). relationships between viral dna molecules synthesized in these two compartments and their role in the virus replication were examined. the data presented here suggest that (i) fv3 dna replicated in two stages and (ii) nucleus and cytoplasm were the sites of stages 1 and 2 of dna replication, respectively. stages 1 and 2 were further distinguished by t ...19827109033
protective effect of colectomy in frog virus 3 hepatitis of rats: possible role of endotoxin.four to six days after colectomy, rats resisted a challenge of frog virus 3 that in sham-operated animals led to lethal hepatitis. furthermore, the beneficial effect of colectomy was lost after intravenous administration of a dose of bacterial endotoxin as small as 0.01 100% lethal dose. the protection was related to neither a different distribution of the virus in body organs nor a stimulation of the reticuloendothelial system. the virus-induced early events--destruction of liver sinusoidal cel ...19827130748
expression of frog virus 3 early genes after ultraviolet irradiation. 19827147709
frog virus 3 requires rna polymerase ii for its replication.the involvement of host cell rna polymerase ii in the replication of frog virus 3 (fv 3) was examined in alpha-amanitin-sensitive or -resistant chinese hamster ovary (cho) cells in the presence and absence of alpha-amanitin. in the presence of alpha-amanitin, fv 3 replicated normally in resistant cho cells but failed to do so in sensitive cho cells. synthesis of virus-specific rnas and proteins was inhibited in sensitive cells infected in the presence of alpha-amanitin, but in alpha-amanitin-res ...19817218429
intracellular distribution and phosphorylation of virus-induced polypeptides in frog virus 3-infected cells. 19817222479
characterization of a temperature-sensitive mutant of frog virus 3 defective in dna replication. 19817245619
penetration and uncoating of frog virus 3 (fv3) in cultured rat kupffer cells. 19817257180
macromolecular synthesis in cells infected by frog virus 3. xiii. cell-free translation of immediate early viral mrnas. 19807352375
structural polypeptides of frog virus 3, phosphorylated proteins. 19807371861
induction of intranuclear microtubules in chick embryo fibroblasts by frog virus 3.intranuclear microtubules appear in chick embryo fibroblasts upon infection with frog virus 3 (fv 3). both the diameter and the annular shape of the microtubule profiles, established from electron microscopic observations using a goniometer, suggest that they are identical to naturally occurring cytoplasmic microtubules. furthermore, the use of vinblastine allowed demonstration of the tubulin composition of the intranuclear microtubules.19807397769
macromolecular synthesis in cells infected by frog virus 3. xiv. characterization of the methylated nucleotide sequences in viral messenger rnas. 19807445431
identification and characterization of the frog virus 3 dna methyltransferase gene.cytosine dna methyltransferases (mtases) first recognize specific nucleotide sequences and then transfer a methyl group from s-adenosylmethionine to cytosine. this division of function is reflected in five highly conserved motifs shared by cytosine mtases. the region containing the first four motifs is responsible for the catalytic function whereas the region containing the fifth motif v provides specificity of binding to dna. in at least one case, two separate proteins, one containing the first ...19957636474
isolation of escherichia coli mutants lacking methylcytosine-dependent restriction systems for cloning extensively methylated frog virus 3 dna.many bacterial strains possess methylation-dependent restriction systems (mdrs) that demonstrate methylcytosine-dependent restriction endonuclease activity for the dinucleotide sequence, dcpdg. this makes these strains unsuitable for cloning methylated dna. some commercially available bacterial cells are recommended for cloning dna fragments with methylated cytosines and adenines, e.g., escherichia coli dh5-alpha mcr. our attempts to clone frog virus 3 (fv3) dna, which has the highest degree of ...19937690339
a fully 5'-cg-3' but not a 5'-ccgg-3' methylated late frog virus 3 promoter retains activity.several lines of evidence demonstrate that the dna of the iridovirus frog virus 3 (fv3) is methylated in all 5'-cg-3' sequences both in virion dna and in the intracellular viral dna at late times after infection. the 5-methyldeoxycytidine residues in this viral dna occur exclusively in 5'-cg-3' dinucleotide positions. we have cloned and determined the nucleotide sequence of the l1140 gene and its promoter from fv3 dna. the gene encodes a 40-kda protein. the results of transcriptional pattern ana ...19957884871
transactivation of methylated hiv-ltr by a frog virus 3 protein.dna methylation has been implicated in the suppression of transcription of a large spectrum of eukaryotic genes. frog virus 3 (fv3) contains genomic dna that is the most extensively methylated of all known animal viruses. however, fv3 gene expression is tightly regulated in a sequential fashion in infected cells. therefore, fv3 must have evolved a mechanism(s) to overcome the inhibitory effects of dna methylation. fv3 has been shown to induce expression of methylated foreign genes in transient t ...19947941333
comparative studies of iridoviruses: further support for a new classification.changes in the classification of invertebrate iridoviruses (ivs) (iridoviridae) have recently been proposed (williams and cory, 1994). the previous system of naming isolates according to the host and sequence of discovery (iv type 1, iv2, iv3, etc.) is not adequate for the purposes of taxonomy, since iridovirus isolates may infect many species, including hosts from diverse invertebrate orders. the new system of invertebrate iridovirus nomenclature, as with several other virus families, is based ...19947975884
instability of frog virus 3 mrna in productively infected cells.cloned dna restriction fragments encoding representative frog virus 3 messages were used as probes to assess the stability of viral transcripts in infected fathead minnow cells. analysis of northern blot hybridization profiles confirmed earlier findings and revealed that in infected cells the steady-state level of representative frog virus 3 (fv3) messages increased throughout the replication cycle. however, when actinomycin d was added at 4 hr after infection to block the synthesis of new trans ...19948030277
proposals for a new classification of iridescent viruses.the need for comparative studies of iridoviruses to elucidate the relationships between them has been well appreciated. sixteen iridoviruses, including type species from each of the four recognized genera of the iridoviridae, were compared by restriction endonuclease characterization, hybridization to the major structural protein (msp) gene of an invertebrate iridescent virus (iv) isolate at various stringencies, pcr amplification of the msp gene region and by dot-blot hybridization studies. the ...19948207395
a preliminary translational map of the frog virus 3 genome.a preliminary map of the frog virus 3 (fv 3) genome was constructed by hybridization-selection of mrnas to cloned dna fragments and translation in reticulocyte lysates. fv 3 mrnas were hybridized to kpni, hindiii, and sali restriction fragments representing the entire fv 3 genome. two different hybridization conditions were employed in order to discriminate between the hybridization of early and late mrnas. a total of 43 major and 18 minor early genes and nine major and three minor late genes we ...19948209422
patterns of frog virus 3 dna methylation and dna methyltransferase activity in nuclei of infected cells.the iridovirus frog virus 3 (fv3) can replicate in culture in fat head minnow (fhm) fish cells or in bhk-21 hamster cells. viral dna replication commences about 3 h after infection of fhm cells with fv3. between 3 and 6 h postinfection (p.i.), a portion of the intranuclear fv3 dna is partly unmethylated. at later times, p.i., all of the viral dna in the nuclear and cytoplasmic compartments is methylated at the 5'-ccgg-3' sequences. cytoplasmic fv3 dna has not been found unmethylated. we have clo ...19938230420
quantification of sinusoidal cell function in vivo.although the clearance and distribution of ligand molecules in circulation represent the function of hepatic sinusoidal cells, these mechanisms revealed a network that is more intricate than would at first seem, since several receptors are common to not only one type of cell, but also to two or three types of cells in the liver. in the case of latex particles in which their uptake by a particular cell type seems to be determined by their size, sinusoidal endothelial cells are able to internalize ...19938446907
cloning, sequence analysis, and expression of the major capsid protein of the iridovirus frog virus 3.the nucleotide sequence of the gene encoding in the major capsid protein (mcp) of frog virus 3 (fv3) has been determined and compared to other iridovirus capsid genes. nucleotide sequence and s1 nuclease analysis showed that the fv3 mcp gene encoded a transcript of 1452 nucleotides containing a 12 nucleotide au-rich 5' nontranslated region (ntr) and a 50-nucleotide 3' ntr whose terminus was predicted to fold into a hairpin of moderate stability. an open reading frame initiating from the the 5'-m ...19968607274
analysis of 76 kb of the chlorella virus pbcv-1 330-kb genome: map positions 182 to 258.analysis of 76 kb of newly sequenced dna, located between map positions 182 and 258 kb in the 330-kb chlorella virus pbcv-1 genome, revealed 175 open reading frames (orfs) of 65 codons or longer. one hundred and five of these 175 orfs were considered major orfs. twenty-one of the 105 major orfs resembled proteins in databases including ribonucleotide reductase small subunit, rnase iii, thioredoxin, glutaredoxin, protein disulfide isomerase, deoxynucleoside kinase, frog virus 3 atpase, acetobacte ...19968806566
identification of the gene encoding the dna (cytosine-5) methyltransferase of lymphocystis disease virus.the gene encoding the dna (cytosine-5) methyltransferase (m5c-mtase) of lymphocystis disease virus (flounder isolate, lcdv-1) has been identified by polymerase chain reaction (pcr) using oligonucleotide primers synthesized corresponding to different regions of the m5c-mtase gene of frog virus 3 (fv3). a dna fragment of 487 bp was amplified using oligonucleotide primers l3 and r4 which correspond to the nucleotide positions 87 to 109 and 530 to 550 of the m5c-mtase gene of fv3, respectively. the ...19968883359
development of dna diagnostic methods for the detection of new fish iridoviral diseases.a new disease of epidemic proportions caused by fish viruses within the iridoviridae family inflicts serious damage on red sea breams (pagrus major) and striped jack (caranx delicatissimus) populations grown in aquacultures in japan. a partial segment of the fish iridoviral dna was directly amplified using the polymerase chain reaction (pcr) with synthetic primers designed from well conserved nucleotide sequences between the frog virus 3 (ranavirus) and the silkworm iridescent virus type 6. the ...19979094219
molecular characterization, sequence analysis, and taxonomic position of newly isolated fish iridoviruses.within the past decade, iridoviruses have been identified as the causative agents of systemic disease in a variety of commercially and recreationally important fish. here we examine nine iridoviruses from fish, reptiles, and amphibians and demonstrate that all isolates were more similar to frog virus 3, the type species of the genus ranavirus, than to lymphocystis disease virus, the type species of the genus lymphocystivirus. comparison of viral protein synthesis profiles, restriction endonuclea ...19979123863
is the major capsid protein of iridoviruses a suitable target for the study of viral evolution?iridoviruses are large cytoplasmic dna viruses that are specific for different insect or vertebrate hosts. the major structural component of the non-enveloped icosahedral virus particles is the major capsid protein (mcp) which appears to be highly conserved among members of the family iridoviridae, phycodnaviridae, and african swine fever virus. the amino acid sequences of the known mcps were used in comparative analyses to elucidate the phylogenic relationships between different cytoplasmic dna ...19989562891
isolation and characterization of iridoviruses from the giant toad bufo marinus in this communication we describe for the first time the isolation of 7 iridoviruses from the toad bufo marinus and an unknown species of frog leptodactylus in venezuela, south america. the viruses are icosahedral with electron-dense cores, each of which is surrounded by an inner membrane, capsid and a cell-derived envelope. the virus(es) have an average vertex to vertex diameter of 160 nm and replicate in the cytoplasm of a range of cell lines. within the cytoplasm of infected cells, rarefied a ...19989653454
comparison of european systemic piscine and amphibian iridoviruses with epizootic haematopoietic necrosis virus and frog virus 3.iridovirus-like agents isolated from systemic infected fish (silurus glanis, sfir; ictalurus melas, cfir i, cfir ii, cfir iii) and from frogs (rana esculenta, reir) in europe, epizootic haematopoietic necrosis virus (ehnv) isolated in australia from redfin perch (perca fluviatilis), and frog virus 3 (fv 3) isolated from frogs (rana pipiens) in the usa were investigated by electron microscopy, polypeptide composition, immunofluorescence, restriction endonuclease digestion, southern-blot hybridiza ...19989719770
pathology, isolation, and preliminary molecular characterization of a novel iridovirus from tiger salamanders in saskatchewan.all iridovirus was confirmed to be the cause of an epizootic in larval and adult tiger salamanders (ambystoma tigrinum diaboli) from four separate ponds in southern saskatchewan (canada) during the summer of 1997. this organism also is suspected, based on electron microscopic findings, to be the cause of mortality of larval tiger salamanders in a pond over 200 km to the north during the same year. salamanders developed a generalized viremia which resulted in various lesions including: necrotizin ...199910479075
molecular characterization of iridoviruses isolated from sympatric amphibians and fish.iridoviruses infect invertebrates (primarily insects and crustaceans) and ectothermic vertebrates (fish, amphibians, and reptiles). identical, or nearly identical viruses, have been isolated from different animals within the same taxonomic class, indicating that infection by a given virus is not limited to a single species. although inter-class infections have been documented following experimental infection with vertebrate iridoviruses, it is not clear whether such infections occur in nature. h ...199910509715
partial mapping and sequencing of a fish iridovirus genome reveals genes homologous to the frog virus 3 p31, p40 and human eif2alpha.iridovirus-like pathogens have been recognized as a cause of serious systemic diseases among feral, cultured and ornamental fish in the recent years. mortalities of fish due to systemic iridovirus infection reaching 30-100% were observed in europe, australia, japan and thailand. up to now, the molecular biology of these important pathogens has been poorly documented. to get better insights on the genomic organization of these piscine iridoviruses, we have constructed a cosmid viral dna library f ...199910509716
isolation and characterization of an iridovirus from hermann's tortoises (testudo hermanni).a virus was isolated from tissues of 2 diseased hermann's tortoises (testudo hermanni) and preliminarily characterized as an iridovirus. this conclusion was based on the presence of inclusion bodies in the cytoplasm of infected cells, sensitivity to chloroform, inhibition of virus replication by 5-iodo-2'-desoxyuridine and the size and icosahedral morphology of viral particles. the virus was able to replicate in several reptilian, avian and mammalian cell lines at 28 degrees c, but not at 37 deg ...199910550665
in vivo and electron microscopic observations of the responses of the hepatic sinusoid to interleukin-1.interleukin-1 (il-1), which is produced by kupffer cells and sinusoidal endothelial cells, may play an important role in immunological and microvascular responses to a variety of stimuli in the liver. the responses of the hepatic microvasculature including phagocytic activity of sinusoidal lining cells to il-1 alpha were examined in c57bl/6 mice in vivo and using electron microscopy. one hour after recombinant mouse il-1 alpha was injected at doses of 80 u, the low dose group, and 800 u, the hig ...199910825814
characterization of an iridescent virus isolated from gryllus bimaculatus (orthoptera: gryllidae).we have isolated an iridescent virus from commercially produced colonies of gryllus bimaculatus in germany, which showed apparent mortality. transmission electron microscopy studies on adult cricket specimens revealed the paracrystalline assembly of icosahedral virus particles in the cytoplasm of hypertrophied abdominal fat body cells. the infecting agent could be cultivated in the lepidopteran cell line sf-9, where it caused cytopathogenic effects such as cell hypertrophy, cytoplasmic vacuoliza ...200111161994
inactivation of frog virus 3 and channel catfish virus by esculentin-2p and ranatuerin-2p, two antimicrobial peptides isolated from frog skin.while it is clear that some amphibian populations have recently experienced precipitous declines, the causes of those die-offs are complex and likely involve multiple variables. one theory suggests that environmental factors may trigger events that result in depressed immune function and increased susceptibility to infectious disease. here we examine one aspect of innate immunity in amphibians and show that esculentin-2p (e2p) and ranatuerin-2p (r2p), two antimicrobial peptides isolated from ran ...200111601906
transcription and temporal cascade in chilo iridescent virus infected cells.chilo iridescent virus (civ) is the type species for genus iridovirus, and belongs to the family iridoviridae. members of this family are large, isometric, cytoplasmic dna viruses. our laboratory has established that civ replicates productively in the cotton boll weevil, anthonomus grandis. given the economic importance of this host and the dearth of knowledge on this virus, we have initiated host-virus interaction and molecular studies on civ. this report focuses on regulation of transcription ...200111765918
comparison of the eif-2alpha homologous proteins of seven ranaviruses (iridoviridae).the alpha-subunit of the eukaryotic initiation factor 2 (eif-2alpha) is a key component of the translation machinery of the cell. in response to cellular stress such as viral infections, eif-2alpha is phosphorylated by double-stranded rna-dependent protein kinase (pkr) leading to the inhibition of cellular protein synthesis. the importance of eif-2alpha as a regulatory mechanism for protein synthesis is illustrated by the wide variety of strategies employed by viruses to down-regulate pkr. thus, ...200111778703
comparative analysis of the genome and host range characteristics of two insect iridoviruses: chilo iridescent virus and a cricket iridovirus isolate.the iridovirus isolate termed cricket iridovirus (criv) was isolated in 1996 from gryllus campestris l. and acheta domesticus l. (both orthoptera, gryllidae). criv dna shows distinct dna restriction patterns different from those known for insect iridescent virus type 6 (iiv-6). this observation led to the assumption that criv might be a new species within the family iridoviridae. criv can be transmitted perorally to orthopteran species, resulting in specific, fatal diseases. these species includ ...200211807240
characterization of an iridovirus from the cultured pig frog rana grylio with lethal syndrome.three virus isolates, rgv-9506, rgv-9807 and rgv-9808, were obtained from cultured pig frogs rana grylio undergoing lethal infections. previously, the first isolate, rgv-9506, was shown to be an iridovirus based on ultrastructural and morphological studies. in the present study, the original isolate, along with 2 recent ones, were more extensively characterized by experimental infection studies, histopathology, electron microscopy, serological reactivity, gel electrophoresis of viral polypeptide ...200111843137
sequence analysis of the complete genome of an iridovirus isolated from the tiger frog.we have isolated a tiger frog virus (tfv) from diseased tiger frogs, rana tigrina rugulosa. the genome was a linear double-stranded dna of 105,057 basepairs in length with a base composition of 55.01% g+c. about 105 open reading frames were identified with coding capacities for polypeptides ranging from 40 to 1294 amino acids. computer-assisted analyses of the deduced amino acid sequences revealed that 39 of 105 putative gene products showed significant homology to functionally characterized pro ...200211878922
ranaviruses (family iridoviridae): emerging cold-blooded killers.although possessing novel replicative and structural features, the family iridoviridae has not been as extensively studied as other families of large, dna-containing viruses (e.g., poxviridae and herpesviridae). this oversight most likely reflects the inability of iridoviruses to infect mammals and birds, and their heretofore low pathogenicity among cold-blooded animals and invertebrates. in fact, the original frog virus isolates (e.g., frog viruses 1-3) would likely have been considered orphan ...200211958449
rapid differentiation of australian, european and american ranaviruses based on variation in major capsid protein gene sequence.epizootic haematopoietic necrosis virus (ehnv), bohle iridovirus (biv) and wamena virus (wv) cause serious diseases in fish, amphibians and snakes, respectively but are restricted to australasia. european catfish virus (ecv) and sheatfish virus (esv) have caused epizootics in fish on farms in continental europe. currently there are no simple or readily available methods to distinguish these viruses, which are in the iridoviridae. they are culturally, morphologically and antigenically very simila ...200212030764
characterization of a novel ranavirus isolated from grouper epinephelus tauvina.a large icosahedral virus was isolated from diseased grouper epinephelus tauvina. the virus grew well in several cultured fish cell lines, with stable and high infectivity after serial passages in grouper cell line (gp). the virus was sensitive to both acid and heat treatments. virus replication was inhibited by 5-iodo-2-deoxyuridine (iudr), indicative of a dna-containing genome. the virus infectivity was reduced with ether treatment, suggesting that the virus was lipid-enveloped. electron micro ...200312608562
induction of apoptosis in frog virus 3-infected cells.the ability of frog virus 3 (fv3), the type species of the family iridoviridae, to induce apoptosis was examined by monitoring dna cleavage, chromatin condensation, and cell-surface expression of phosphotidylserine (ps) in fathead minnow (fhm) and baby hamster kidney (bhk) cells. in productively infected fhm cells, dna fragmentation was first noted at 6-7 h postinfection and was clearly seen by 17 h postinfection, while chromatin condensation was detected at 8.5 h postinfection. as with some oth ...200312642103
development and characterization of a model system to study amphibian immune responses to iridoviruses.the recent realization that viruses within the family iridoviridae may contribute to the worldwide decline in amphibians makes it urgent to understand amphibian antiviral immune defenses. we present evidence that establishes the frog xenopus laevis as an important model with which to study anti-iridovirus immunity. adults resist high doses of fv3 infection, showing only transitory signs of pathology. by contrast, naturally mhc class-i-deficient tadpoles are highly susceptible to fv3 infection. m ...200312842616
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