scholarly journals Phenotypic Diversity of Infectious Red Sea Bream Iridovirus Isolates from Cultured Fish in Japan

2009 ◽  
Vol 75 (11) ◽  
pp. 3535-3541 ◽  
Author(s):  
Hajime Shinmoto ◽  
Ken Taniguchi ◽  
Takuya Ikawa ◽  
Kenji Kawai ◽  
Syun-ichirou Oshima
Keyword(s):  
Red Sea ◽  
Phenotypic Diversity ◽  
Sea Bream ◽  
Cell Culture Supernatant ◽  
Red Sea Bream ◽  
Virus Family ◽  
Recent Emergence ◽  
Infected Cells

ABSTRACT Megalocytivirus is causing economically serious mass mortality by infecting fish in and around the Pacific region of Asia. The recent emergence of many new iridoviruses has drawn attention to the marked taxonomic variation within this virus family. Most studies of these viruses have not included extensive study of these emergent species. We explored the emergence of red sea bream iridovirus (RSIV) on a fish farm in Japan, and we specifically endeavored to quantify genetic and phenotypic differences between RSIV isolates using in vitro and in vivo methods. The three isolates had identical major capsid protein sequences, and they were closely related to Korean RSIV isolates. In vitro studies revealed that the isolates differed in replication rate, which was determined by real-time quantitative PCR of viral genomes in infected cells and cell culture supernatant, and in cell viability, estimated by the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay for infected cells. In vivo studies showed that the isolates exhibit different virulence characteristics: infected red sea bream showed either acute death or subacute death according to infection with different isolates. Significant differences were seen in the antigenicity of isolates by a formalin-inactivated vaccine test. These results revealed that variant characteristics exist in the same phylogenetic location in emergent iridoviruses. We suggest that this strain variation would expand the host range in iridoviral epidemics.

scholarly journals ELECTRON MICROSCOPIC STUDY ON ENLARGED CELLS OF RED SEA BREAM, Pagrus major INFECTED BY THE RED SEA BREAM IRIDOVIRUS (RSIV, GENUS Megalocytivirus, FAMILY Iridoviridae)

2009 ◽  
Vol 4 (1) ◽  
pp. 53
Author(s):  
Ketut Mahardika
Keyword(s):  
Electron Microscope ◽  
Inclusion Body ◽  
Red Sea ◽  
Virus Assembly ◽  
Infected Fish ◽  
Sea Bream ◽  
Red Sea Bream ◽  
Electron Microscopic ◽  
Target Organs ◽  
Infected Cells

Most histopathologycal studies of the red sea bream iridovirus (RSIV) disease in red sea bream have been performed by studying enlarged cells as well as necrotized cells in the spleen and other organs. These enlarged cells have been named as inclusion body bearing cells (IBCs). However, few information is available about detail of ultrastructural features of IBCs produced in the target organs of RSIV-infected fish. In the present study, details of ultrastructural features of IBCs that were produced in the spleen tissue of naturally RSIV-infected red sea bream were investigated under electron microscope. Under electron microscope, RSIV-infected red sea bream had the presence of two types of IBCs: typical IBCs allowing virus assembly within viral assembly site (VAS), and atypical IBCs which degenerate organelles without virus assembly. Other infected-cells were observed as necrotized cells forming intracytoplasmic VAS with large numbers of virions, but without the formation of the distinct inclusion body. Morphogenesis steps on RSIV-infected red sea bream were observed as filamentous-filed virions, partially-filled virions and complete virions with 145-150 nm in size. These findings confirmed that RSIV-infected red sea bream were characterized by formation of typical and atypical IBCs as well as necrotized cells.

Isolation and characterisation of an ISKNV-genotype megalocytivirus from imported angelfish Pterophyllum scalare

2020 ◽  
Vol 140 ◽  
pp. 129-141
Author(s):  
Y Kawato ◽  
PG Mohr ◽  
MStJ Crane ◽  
LM Williams ◽  
MJ Neave ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Red Sea ◽  
Sea Bream ◽  
Whole Genome ◽  
Red Sea Bream ◽  
Capsid Protein Gene ◽  
Infected Cells ◽  
Clade 1 ◽  
Pterophyllum Scalare

Using cultures of the SKF-9 cell line, megalocytivirus AFIV-16 was isolated from imported angelfish Pterophyllum scalare held in quarantine at the Australian border. The cytopathic effect caused by isolate AFIV-16 presented as cell rounding and enlargement, but complete destruction of the infected cell cultures did not occur. The infected cells demonstrated immunocytochemical reactivity with monoclonal antibody M10, which is used for diagnosis of OIE-listed red sea bream iridoviral disease. Using electron microscopy, the virus particles, consisting of hexagonal nucleocapsids, were observed in the cytoplasm of SKF-9 cells. The replication of AFIV-16 in cultured SKF-9 cells was significantly greater at 28°C incubation than at 22 and 25°C incubation, whereas no difference in growth characteristics was observed for red sea bream iridovirus (RSIV) isolate KagYT-96 across this temperature range. Whole genome sequencing demonstrated that AFIV-16 has a 99.96% similarity to infectious spleen and kidney necrosis virus (ISKNV), the type species in the genus Megalocytivirus. AFIV-16 was classified into ISKNV genotype Clade 1 by phylogenetic analysis of the major capsid protein gene nucleotide sequence. This is the first report of whole genome sequencing of an ISKNV genotype megalocytivirus isolated from ornamental fish.

scholarly journals Induction of Oocyte Maturation in vitro by Steroid Hormones in the Red Sea Bream Pagrus major

1988 ◽  
Vol 54 (9) ◽  
pp. 1665-1665 ◽  
Author(s):  
Shinji Adachi ◽  
Kazuomi Ouchi ◽  
Keiji Hirose ◽  
Yoshitaka Nagahama
Keyword(s):  
Steroid Hormones ◽  
Red Sea ◽  
Oocyte Maturation ◽  
Sea Bream ◽  
Red Sea Bream ◽  
Pagrus Major

scholarly journals Transcription Program of Red Sea Bream Iridovirus as Revealed by DNA Microarrays

2005 ◽  
Vol 79 (24) ◽  
pp. 15151-15164 ◽  
Author(s):  
Dang Thi Lua ◽  
Motoshige Yasuike ◽  
Ikuo Hirono ◽  
Takashi Aoki
Keyword(s):  
Gene Expression ◽  
Dna Replication ◽  
Red Sea ◽  
Sea Bream ◽  
Protein Synthesis Inhibitor ◽  
Red Sea Bream ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Transcription Program

ABSTRACT Red sea bream iridovirus (RSIV) has been identified as the causative agent of a serious disease in red sea bream and at least 30 other marine fish species. We developed a viral DNA microarray containing 92 putative open reading frames of RSIV to monitor the viral gene transcription program over the time course of an in vitro infection and to classify RSIV transcripts into temporal kinetic expression classes. The microarray analysis showed that viral genes commenced expression as early as 3 h postinfection (p.i.) and this was followed by a rapid escalation of gene expression from 8 h p.i. onwards. Based on the expression of some enzymes associated with viral DNA replication, the DNA replication of RSIV appeared to begin at around 8 h p.i. in infected cells in vitro. Using a de novo protein synthesis inhibitor (cycloheximide) and a viral DNA replication inhibitor (phosphonoacetic acid), 87 RSIV transcripts could be classified into three temporal kinetic classes: nine immediate-early (IE), 40 early (E), and 38 late (L) transcripts. The gene expression of RSIV occurred in a temporal kinetic cascade with three stages (IE, E, and L). Although the three classes of transcripts were distributed throughout the RSIV genome, E transcripts appeared to cluster in at least six discrete regions and L transcripts appeared to originate from seven discrete regions. The microarray data were statistically confirmed by using a t test, and were also clustered into groups based on similarity in the gene expression patterns by using a cluster program.

scholarly journals ULTRASTRUCTURAL ANALYSIS OF GRUNT FIN (GF) CELLS TREATED WITH RED SEA BREAM IRIDOVIRUS (RSIV; family Iridoviridae, genus Megalocytivirus) IN COMBINATIONS WITH INTERFERONS AND SPLENIC SUBSTANCES

2010 ◽  
Vol 5 (1) ◽  
pp. 19
Author(s):  
Ketut Mahardika ◽  
Teruo Miyazaki
Keyword(s):  
Red Sea ◽  
Virus Assembly ◽  
Cell Types ◽  
Sea Bream ◽  
Interferon Α ◽  
Type I ◽  
Viral Titer ◽  
Red Sea Bream ◽  
Virus Propagation

The genus Megalocytivirus in the family of Iridoviridae encompasses isolate of red sea bream iridovirus (RSIV). In the present study, grunt fin (GF) cells were treated with red sea bream iridovirus (RSIV) in combinations with interferons (IFNs) and splenic substances. The viral titer in the combination with primary splenic substance was higher than the other combinations of 10-1 and 10-2 diluted splenic substances, and the positive control. The viral titer was not decreased by all combinations with recombinant murine interferon-α (rMuIFN-α), recombinant murine IFN-β (rMuIFN-β), and recombinant feline interferon-ω (rFeIFN-ω). Electron microscopy revealed inclusion body bearing cells (IBCs) and enlarged cells allowing virus propagation within the intracytoplasmic virus assembly site (VAS). Most were enlarged cells. These enlarged cells were divided into three cell types. Cells of Type II, which contained many mature virions within the VAS, were numerous in number in all treated cells. Cells of Type I allowing assembly of few virions and cells of Type III containing many immature viral particles were rather fewer in number. Their percentage was almost the same in all combinations with the splenic substances and IFNs. These results determined in in vitro treatment with IFNs did not prevent viral replication of RSIV, as well as the splenic substances which were derived from the RSIV-infected spleen of red sea bream did not contain any factors to disturb RSIV replication.

Purification, characterization, and molecular cloning of group I phospholipases A2 from the gills of the red sea bream, Pagrus major

Lipids ◽  
2000 ◽  
Vol 35 (12) ◽  
pp. 1359-1371 ◽  
Author(s):  
Noriaki Iijima ◽  
Satoshi Uchiyama ◽  
Yukichi Fujikawa ◽  
Muneharu Esaka
Keyword(s):  
Molecular Cloning ◽  
Red Sea ◽  
Sea Bream ◽  
Red Sea Bream ◽  
Pagrus Major ◽  
Phospholipases A2 ◽  
Group I

Studies of two temperature-sensitive mutants of Mengo virus

1979 ◽  
Vol 57 (6) ◽  
pp. 902-913 ◽  
Author(s):  
Patrick W. K. Lee ◽  
John S. Colter
Keyword(s):  
Rna Synthesis ◽  
Viral Rna ◽  
Temperature Sensitive ◽  
Supporting Evidence ◽  
Structural Polypeptide ◽  
Infected Cells ◽  
Mengo Virus ◽  
In Vitro Stability

Studies of the synthesis of viral ribonucleates and polypeptides in cells infected with two RNA−ts mutants of Mengo virus (ts 135 and ts 520) have shown that when ts 135 infected cells are shifted from the permissive (33 °C) to the nonpermissive (39 °C) temperature: (i) the synthesis of all three species of viral RNA (single stranded, replicative form, and replicative intermediate) is inhibited to about the same extent, and (ii) the posttranslational cleavage of structural polypeptide precursors A and B is partially blocked. Investigations of the in vivo and in vitro stability of the viral RNA replicase suggest that the RNA− phentotype reflects a temperature-sensitive defect in the enzyme. The second defect does not appear to result from the inhibition of viral RNA synthesis at 39 °C, since normal cleavage of polypeptides A and B occurs in wt Mengo-infected cells in which viral RNA synthesis is blocked by cordycepin, and at the nonpermissive temperature in ts 520 infected cells. Considered in toto, the evidence suggests that ts 135 is a double mutant.Subviral (53 S) particles have been shown to accumulate in ts 520 (but not ts 135) infected cells when cultures are shifted from 33 to 39 °C. This observation provides supporting evidence for the proposal that this recently discovered particle is an intermediate in the assembly pathway of Mengo virions.

Sign in / Sign up

Export Citation Format

Share Document