• 한국어병학회지
• /
• 제28권2호
• /
• pp.113-116
• /
• 2015

A $0.45-{\mu}m$ membrane filter is generally used to remove bacterial contamination during virus extraction from fish samples. However, the number of fish viruses is drastically reduced after filtration with a $0.45{\mu}m$ filter. In this study, we investigated the effect of filters on virus infectivity titer and the change in virus titer and bacterial number following different centrifugation conditions to determine a suitable procedure for virus extraction from fish samples. $10^{4.05}$ and $10^{5.05}TCID_{50}/ml$ of infectious hematopoietic necrosis virus (IHNV) and $10^{4.05}$ and $10^{4.55}TCID_{50}/ml$ of Oncorhynchus masou virus (OMV) were not detectable after filtration with two types of $0.45-{\mu}m$ filters, except the IHNV titer was reduced by about 10 fold after filter use (company A). No significant difference was found in the virus titer following centrifugation at $880{\times}g$ (30 min) or $3,500{\times}g$ (30 min), whereas IHNV and OMV titers were reduced by about 10 and 10-1000 fold by centrifugation at $14,000{\times}g$ (30 min) and $14,000{\times}g$ (10 and 30 min), respectively. A total of 97.7-99.9% Escherichia coli were eliminated by centrifugation at $880 {\times}g$ (30 min) and $3,500{\times}g$ (30 min). These results show that fish viruses were affected by filtering, even though the effect differed by virus species and filter type. Therefore, centrifugation at $3,500{\times}g$ (30 min) and use of medium with antibiotics may be useful for virus extraction along with a reduction in bacteria.

• 한국발생생물학회지:발생과생식
• /
• 제27권2호
• /
• pp.67-75
• /
• 2023

Polymeric immunoglobulin receptor (pIgR) mediates the transfer of polymeric immunoglobulin to protect organisms and is one of the most important mucosal effectors. In this study, the developmental stage- and tissue-specific expression of pIgR were observed before virus inoculation in olive flounder. pIgR was gradually expressed until the formation of immune tissue, exhibiting high expression in the late juvenile period; thereafter, pIgR expression gradually decreased and exhibited high expression in the spleen and skin. Moreover, pIgR expression after viral hemorrhagic septicemia virus infection was high in the kidney and spleen tissues at high density and low at low density. The results of this study can provide a basis for future studies on breeding density, virus expression, and immune system studies in fish.

• 한국어병학회지
• /
• 제33권1호
• /
• pp.71-75
• /
• 2020

A survey was conducted to investigate viral infections in 184 whiteleg shrimp (Litopenaeus vannamei) collected from nine farms and one wholesale fish vendor during 2018 and 2019. Gill and abdominal muscle of shrimp were tested for the presence of five viruses, viz. infectious hypodermal and haematopoietic necrosis virus, taura syndrome virus, infectious myonecrosis virus, yellow head virus genotype 1, and covert mortality nodavirus by reverse transcription-polymerase chain reaction (RT-PCR) and PCR. These viruses were not detected in any of 184 samples, screened under the study.

• 한국어병학회지
• /
• 제25권2호
• /
• pp.117-121
• /
• 2012

The pathogenicity of viral hemorrhagic septicemia virus (VHSV) from olive flounder Paralichthys olivaceus was investigated with masu salmon Oncorhynchus masou fry. The cumulative mortality of fish challenged with FYeosu05 isolate at $10^{6.5}$ $TCID_{50}$/fish was 60%. No mortality was observed in fish challenged with the isolates at $10^{5.5}$ $TCID_{50}$/fish and in mock-challenged fish. The affected fish showed darkening of the body, expanded abdomen, pale gills and enlarged spleen. VHSV from $10^{6.3}$ to $10^{7.8}$ $TCID_{50}$/g-tissue was re-isolated from the dead fish. These results suggest that the VHSV from olive flounder is pathogenic to masu salmon fry, although with low virulence.

• 한국어병학회지
• /
• 제23권3호
• /
• pp.335-342
• /
• 2010

2008년 3월 인도네시아로부터 수입된 paradise fish에서 대량폐사가 발생하여 병원체 검사를 실시한 결과, megalocytivirus 및 Mycobacterium sp.가 검출되었으며, CHSE-214세포에서 미동정 바이러스가 분리되었다. 본 연구에서는 미동정 바이러스의 특성을 조사하였으며, 또한 병원성 실험을 통해 paradise fish의 대량 폐사와의 연관성을 조사하였다. 분리 바이러스는 CHSE-214, BF-2, GF, SSN-1, FSP 및 FFN 세포에서 합포체의 세포변성효과를 나타내었고 IUdR 및 chloroform 처리에 감염성이 상실되지 않으며, 산 (pH 3), 알카리 (pH 11) 및 열 ($56^{\circ}C$, 30분)에 안정하였다. 핵산 분석 결과에서는 적어도 10개의 segment (0.7-3.6 kb)를 지닌 RNA 바이러스로 확인되었으며, 전자현미경 관찰 결과, 약 65 nm 크기로 인벨롭이 없으며 2중의 capsid를 지닌 바이러스가 세포질에서 관찰되었다. 이상의 결과는 Reoviridae family에 속하는 바이러스의 전형적인 특성과 일치하므로 paradise fish에서 분리된 바이러스는 reovirus로 확인되었다. Reovirus를 사용한 감염실험에서는 병원성이 나타나지 않아, reovirus는 paradise fish의 대량 폐사의 직접적인 원인이 아닐 것으로 사료되었다.

• 한국어류학회지
• /
• 제27권3호
• /
• pp.183-188
• /
• 2015

본 연구에서는 무지개송어의 해수면 양식장으로의 이동에 따라 나타날 수 있는 어류 병원성 바이러스의 영향을 알아보기 위해, 담수 무지개송어 유래 병원체인 infectious hematopoietic necrosis virus (IHNV)와 infectious pancreatic necrosis virus (IPNV)를 사용하여 주요 해산 양식 어종인 넙치, 조피볼락, 돌돔, 참돔 및 능성어에 주사한 후 병원성 및 감염 여부를 조사하였으며, 또한 해산 양식 어종 유래 병원체인 marine birnavirus (MABV), hirame rhabdovirus (HIRRV) 및 nervous necrosis virus (NNV)를 사용하여 무지개송어에 대한 병원성 및 감염 여부를 조사하였다. IHNV와 IPNV는 주요 해산 양식 어종에 감염되는 것으로 확인되었으며, 또한 무지개송어는 해산 유래 위해 병원체인 MABV와 NNV에 감염되거나 HIRRV에 의해 폐사되는 것으로 확인되었다. 이상의 연구 결과, 해수사육 무지개송어는 어류 병원성 바이러스들에 의해 영향 받을 수 있을 것으로 사료되었다.

• Fisheries and Aquatic Sciences
• /
• 제1권2호
• /
• pp.187-191
• /
• 1998

Chemotherapy can not be applied for the control of fish viral diseases because viruses depend on host machinery for their replication. Although new control strategies including vaccination are under development, avoidance of virus introduction by rapid and correct diagnosis is the best way of fish viral disease control. Although observation of virus particles with an electron microscope is an easy method for virus detection, it take a few days for the sample preparation. In order to shorten the sample preparation time, microwave radiation was applied in the procedure. With this method, 15 seconds was enough for fixation of virus infected fish samples or cultured cells inoculated with infectious hematopoietic necrosis virus, which takes 2-4 hours with routine methods. Also four minutes was enough for polymerization of embedding resin which takes 24-48 hours with routine methods. Samples prepared with microwave were good enough for direct electron microscopic observation and immunogold labeling assay.

• Fisheries and Aquatic Sciences
• /
• 제8권3호
• /
• pp.185-187
• /
• 2005

We tested the in vivo ability of a DNA chip to detect virus-specific genes from virus-infected olive flounder Paralichthys olivaceus and rainbow trout Oncorhynchus mykiss. Target cDNA was obtained from total RNA of virus infected cell lines by reverse transcription (RT) and was labeled with fluorescent dye (Cy5-dUTP). The results show the successful detection of infectious hematopoietic necrosis virus (IHNV) and viral hemorrhagic septicaemia virus (VHSV) genes in the virus-infected fishes.

• Journal of Microbiology
• /
• 제34권3호
• /
• pp.253-269
• /
• 1996

Infection of fish cells with IHNV resulted in gradual increase in cytosolic free Ca$\^$2+/ concentration ([Ca$\^$2+/)] in CHSE, gradual decrease in [Ca$\^$2+/] in FHM, and no significant change in RTG cells. The degree of [Ca$\^$2+/] increase or decrease was dependent on the amount of infectious virus, and these [Ca$\^$2+/] variations were maximal at 16 hours after virus infection (p. i.) in both cell lines. When the fish cells were infected with inactivated IHNV, evident variation in [Ca$\^$2+/] was not observed. Thus, infectivity of IHNV appears to correlate with changes in [Ca$\^$2+/] in virus-infected cells. These IHNV-induced [Ca$\^$2+/] changes were partially blocked by cycloheximide, but not affected by cordycepin. It seems to be that virus-induced Ca$\^$2+/ variations were more related with protein synthesis than RNA synthesis. Various Ca$\^$2+/ related drugs were used in search for the mechanisms of the [Ca$\^$2+/], changes following IHNV infection of CHSE cells. Decreasing extracellular Ca$\^$2+/ concentration or blocking Ca$\^$2+/ influx from extracellular media inhibited the IHNV-induced increase in [Ca$\^$2+/], in CHSE cells. Similar results were obtained with intracellular Ca$\^$2+/ sources are important in IHNV-induced [Ca$\^$2+/] increase in CHSE cells.

• 한국어병학회지
• /
• 제23권3호
• /
• 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.