• Title, Summary, Keyword: Rock bream

Search Result 83, Processing Time 0.044 seconds

Characterization of Asymptomatic Megalocytivirus Infection in farmed Rock Fish (Sebastes schlegeli) in Korea (양식 조피볼락 (Sebastes schlegeli)에서 megalocytivirus의 무증상적 감염과 특성 분석)

  • KWON, Woo-Ju;KIM, Young-Chul;YOON, Min-Ji;JEONG, Hyun-Do
    • Journal of Fisheries and Marine Sciences Education
    • /
    • v.27 no.4
    • /
    • pp.1184-1193
    • /
    • 2015
  • Monitoring for megalocytivirus infection was conducted for ten months from March to December in 2013 in 15 aquatic farms culturing, red sea bream, rock bream, rock fish and black sea bream around Tongyoung coastal area in Korea, to assess spatial and temporal variability of detection prevalence, and to explore possible links with seawater temperature. In nested-PCR targeted major capsid protein (MCP) gene, asymptomatic megalocytivirus infection was detected in the externally healthy farmed fish with a significant prevalence in range from 0 to 58.3% for ten months. Higher prevalence of megalocytivirus (46.7% - 57.1%) was observed in high water temperature season from September to November than that in other months with lower prevalence of 0.0% to 20.0%. Even though an acute infection of megalocytivirus was occurred in rock bream (positive in the first PCR) with high mortality in one of fifteen farms, there was no expansion or transmission of the disease to the rock fish and red sea bream culturing in net cage just proximal to the rock bream cage in which disease outbreaked. Nucleotide sequence analysis of the cloned MCP gene isolated asymptomatically infected rock fish revealed that the megalocytivirus in this study was clustered together with the rock bream iridovirus (RBIV) under the subgroup II of the genus megalocytivirus (Iridoviridae), which is known to be the major megalocytivirus strain in Korea. The typical histopathological signs were not found in the spleen of rock fish asymptomatically infected by megalocytivirus. Experimental infection of rock bream with the spleen homogenate of the rock fish infected asymptomatically did not induce any mortality unlike the homogenate of infected rock bream with hih mortlity. However, these results may suggest that the asymptomatic infection of megalocytivirus in other fish species can be a potential risk threatening aquaculture industries as a transmission factor of megalocytivirus to susceptible fish species, especially rock bream.

Correlation of virus replication and spleen index in rock bream iridovirus infected rock bream Oplegnathus fasciatus

  • Jung, Myung-Hwa;Jung, Sung-Ju
    • Journal of fish pathology
    • /
    • v.32 no.1
    • /
    • pp.1-8
    • /
    • 2019
  • Rock bream iridovirus (RBIV) is a member of the Megalocytivirus genus that causes severe mortality to rock bream (Oplegnathus fasciatus) with characteristic clinical signs of spleen enlargement. In this study, we assessed spleen size and RBIV copy number patterns in RBIV-infected rock bream to determine lethal and safe levels of virus copy number/spleen index that may define disease progress. We found that rock bream infected with RBIV ($1.1{\times}10^7virus\;copy\;number/100{\mu}l$) and held at 29, 26, 23 or $20^{\circ}C$ exhibited significantly higher levels of spleen size compared to $17^{\circ}C$. In dead condition (100% mortality at $20{\sim}29^{\circ}C$), the spleen index ($spleen\;weight/fish\;weight{\times}100$) and virus copy number were 3.00~5.38 and $10^6{\sim}10^8/{\mu}l$, respectively. Conversely, in survived condition (0% mortality at $17^{\circ}C$), spleen index and virus copy number was as low as not-infected control ($0.34{\sim}1.22/10^0{\sim}10^1/{\mu}l$, respectively). These findings suggest that spleen index can be an indicator of disease severity of RBIV disease.

Quantitative analysis of the clinical signs in marine fish induced by Megalocytivirus infection (Megalocytivirus 감염 해산 어류에서 나타나는 임상증상의 정량적 변화 분석)

  • Jin, Ji-Woong;Cho, Hye-Jin;Kim, Kwang-Il;Jeong, Joon-Bum;Park, Gyeong-Hyun;Jeong, Hyun-Do
    • Journal of fish pathology
    • /
    • v.24 no.2
    • /
    • pp.53-64
    • /
    • 2011
  • In quantitative studies of clinical signs, rock bream of adults and juveniles infected with Megalocytivirus IVS-1 isolated from rock bream (Oplegnathus fasciatus) in Korea showed average $4.49{\pm}1.13$ and $4.85{\pm}1.06$ of spleen index respectively. In challenge experiments, Megalocytivirus IVS-1 induced 100% cumulative mortality in both adult and juvenile rock bream. However we found 60% cumulative mortality in juvenile red sea bream (Pagrus major) even after 30 days of injection, which contradicted with the results of other laboratories. Interestingly, IVS-1 infected red sea bream of the same juvenile size with rock bream showed lower spleen index compared to that of rock bream. In real-time PCR, there was continuous increasing of the numbers of viral copies ($2.03{\times}10^7$ copies/mg) in the spleen of juvenile rock bream infected, which were different from those in adult rock bream showing plateau level after reaching to the peak level. Moreover, enlarged cell numbers in the infected spleen were also increased continuously in the juvenile but not in adult of rock bream, even decreased after reaching to peak level. Consequently, significant differences in clinical signs: cumulative mortality. spleen index and viral copy number were found between rock bream and red sea bream, but not between adult and juvenile rock bream. Certainly quantitative expression of clinical sign as in this study may be a way to compare the progression of megalocitiviral disease more accurately in different species or physiological conditions.

Acquired resistance of rock bream (Oplegnathus fasciatus) against rock bream iridovirus (RBIV) through undergoing low water temperature period

  • Zenke, Kosuke;Yoon, Ki Joon;Kim, Min Sun;Choi, Seung Hyuk;Kim, Ki Hong
    • Journal of fish pathology
    • /
    • v.27 no.2
    • /
    • pp.85-89
    • /
    • 2014
  • Water temperature is a key environmental factor controlling the epizootics of viral diseases in fish. High water temperature is associated with the rapid spread of rock bream iridovirus (RBIV) disease and with high mortality of RBIV infected fish. Although protection of fish against iridoviral disease by active immunization has been reported, little information is available concerning whether fish survived from an epizootic of iridoviral disease can naturally acquire resistance against the viral disease. In the present study, we have demonstrated that juvenile rock bream, which survived from a natural epizootic of RBIV, acquired resistance against recurrence or reinfection of RBIV, and this resistance was established during the subsequent low water temperature period. Furthermore, the possible involvement of the adaptive humoral immune response in the resistance of the juvenile rock bream was suggested by in vivo neutralization experiment.

Light and electron microscopic observations of Ceratomyxa sparusaurati (Myxosporea: Bivalvulida) from the gall bladder of rock bream (Oplegnathus fasciatus)

  • Cho, Jae Bum;Kim, Ki Hong
    • Journal of fish pathology
    • /
    • v.29 no.1
    • /
    • pp.7-12
    • /
    • 2016
  • In a previous study on the parasites of cultured rock bream (Oplegnathus fasciatus), we reported the discovery of a new species, Ceratomyxa oplegnathus, obtained from the gallbladder. In the present study, we found another Ceratomyxa species, C. sparusaurati, also from the gallbladder of rock bream. The morphological and ultrastructural characteristics of C. sparusaurati were investigated using light and transmission electron microscopy (TEM).

Expression Analysis of Interferon-Stimulated Gene 15 in the Rock Bream Oplegnathus fasciatus against Rock Bream Iridovirus (RSIV) Challenge

  • Kim, Kyung-Hee;Yang, In Jung;Kim, Woo-Jin;Park, Choul-Ji;Park, Jong-Won;Noh, Gyeong Eon;Lee, Seunghyung;Lee, Young Mee;Hwang, Hyung Kyu;Kim, Hyun Chul
    • Development and Reproduction
    • /
    • v.21 no.4
    • /
    • pp.371-378
    • /
    • 2017
  • Interferon-stimulated gene 15 (ISG15) is known to interfere with viral replication and infection by limiting the viral infection of cells. Interferon-stimulated gene 15 (ISG15) interferes with viral replication and infectivity by limiting viral infection in cells. It also plays an important role in the immune response. In this study, tissue-specific expression of ISG15 in healthy rock bream samples and spatial and temporal expression analysis of rock bream ISG15 (RbISG15) were performed following rock bream iridovirus (RSIV) infection. RbISG15 expression was significantly higher in the eye, gill, intestine, kidney, liver, muscle, spleen, and stomach, but low in the brain. There were particularly high levels of expression in the liver and muscle. RbISG15 expression was also examined in several tissues and at various times following RSIV infection. ISG15 expression increased within 3 h in the whole body and decreased at 24 h after infection. In addition, temporal expression of several tissues following RSIV infection showed a similar pattern in the muscle, kidney, and spleen, increasing at 3 h and decreasing at 72 h. These results suggest that ISG15 plays an important role in the immune response of rock bream. Overall, this study characterizes the response of RbISG15 following RSIV infection.

Molecular cloning and expression analysis of an interferon stimulated gene 15 from rock bream Oplegnathus fasciatus

  • Kim, Ju-Won;Kwon, Mun-Gyeong;Park, Myoung-Ae;Hwang, Jee-Youn;Park, Hyung-Jun;Baeck, Gun-Wook;Kim, Mu-Chan;Park, Chan-Il
    • Journal of fish pathology
    • /
    • v.23 no.2
    • /
    • pp.177-187
    • /
    • 2010
  • The Interferon stimulated gene 15 (ISG15) is strongly induced in many cell types by IFNs, viral infections, and double-stranded RNA (poly I:C). The ISG15 homologue cDNA was isolated from the rock bream LPS stimulated leukocyte cDNA library. The rock bream ISG15 homologue was found to consist of 833 bp encoding 157 amino acid residues. Compared with other known ISG15 peptide sequences, the most conserved regions of the rock bream ISG15 peptide were found to be the tandem ubiquitin-like domains and a C-terminal LRLRGG conjugating motif, characteristic of mammalian and non-mammalian ISG15 proteins. Phylogenetic analysis based on the deduced amino acid sequence revealed a homologous relationship between the ISG15 sequence of rock bream and that of Atlantic salmon, Atlantic cod, northern snake head, black rockfish and olive flounder. The expression of the rock bream ISG15 molecule was induced in the peripheral blood leukocytes (PBLs) from 1 to 24 h following poly I:C stimulation, with a peak at 3 h post-stimulation. The rock bream ISG15 gene was predominantly expressed in the PBLs, spleen and gill.

Effects of long double-stranded RNAs on the resistance of rock bream Oplegnathus fasciatus fingerling against rock bream iridovirus (RBIV) challenge

  • Kosuke, Zenke;Kim, Ki-Hong
    • Journal of fish pathology
    • /
    • v.23 no.3
    • /
    • pp.273-280
    • /
    • 2010
  • To determine whether rock bream Oplegnathus fasciatus can be protected from rock bream iridovirus (RBIV) infection by intramuscular injection of long double-stranded RNAs (dsRNAs), we compared protective effect of virus-specific dsRNAs corresponding to major capsid protein (MCP), ORF 084, ORF 086 genes, and virus non-specific green fluorescent protein (GFP) gene. Furthermore, to determine whether the non-specific type I interferon (IFN) response was associated with protective effect, we estimated the activation of type I IFN response in fish using expression level of IFN inducible Mx gene as a marker. As a result, mortality of fish injected with dsRNAs and challenged with RBIV was delayed for a few days when comparing with PBS injected control group. However, virus-specific dsRNA injected groups exhibited no significant differences in survival period when compared to the GFP dsRNA injected group. Semi-quantitative analysis indicated that the degree of antiviral response via type I IFN response is supposedly equal among dsRNA injected fish. These results suggest that type I IFN response rather than sequence-specific RNA interference might involve in the lengthened survival period of fish injected with virus-specific dsRNAs.

Long Double-stranded RNA Induces Sequence-specific RNA Interference and Type I Interferon Responses in Rock Bream (Oplegnathus fasciatus)

  • Zenke, Kosuke;Kim, Ki-Hong
    • Fisheries and aquatic sciences
    • /
    • v.13 no.1
    • /
    • pp.56-62
    • /
    • 2010
  • To determine whether long double-stranded RNA (dsRNA) induces RNA interference and type I interferon (IFN) responses in fish, long dsRNAs encoding enhanced green fluorescent protein (EGFP), GFPuv, and polyinosinic-polycytidylic acid sequences were co-injected with an EGFP expressing plasmid, into rock bream (Oplegnathus fasciatus). We investigated the EGFP mRNA and protein levels, and the transcriptional responses of dsRNA-dependent protein kinase and Mx1 genes. Long dsRNAs were strong inducers of a type I IFN response in rock bream, resulting in nonspecific suppression of exogenous gene expression. Furthermore, sequence-specific knockdown of exogenous gene expression at the mRNA level was detected at an early phase (24 h). These results suggested that long dsRNA may inhibit exogenous gene expression through an early mRNA interference response and a later type I IFN response in fish.

Effects of Starvation in Rock Bream, Oplegnathus fasciatus and Olive Flounder, Paralichthys olivaceus

  • Park, In-Seok;Gil, Hyun Woo;Yoo, Gwang Yeol;Oh, Ji Su
    • Development and Reproduction
    • /
    • v.19 no.2
    • /
    • pp.97-109
    • /
    • 2015
  • We assessed the effects of various dietary conditions on the growth, phenotypic traits, and morphometric dimensions of rock bream, Oplegnathus fasciatus and on the morphometric dimensions of sectioned olive flounder, Paralichthys olivaceus. Rock bream in the fed group increased in body weight, standard length, and condition factor, but these parameters decreased significantly for fish in the starved group (P < 0.05). The head connection dimensions of fish in the fed group decreased, while for starved fish there was increase in external morphometric dimensions (P < 0.05). In both species, sectioned morphometric analysis revealed that fish in the fed group had a larger body circumference and cross-cut sectional area, and greater cross-cut section height, relative to the starved group (P < 0.05).