• Journal of fish pathology
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• v.35 no.1
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• pp.129-133
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• 2022

The full genome sequence of a Korean white spot syndrome virus (WSSV, isolate: WSSV-GoC18) is presented here. We obtained a total of 12,320,554 reads with 291,172 bases, 170 gene, and 170 coding DNA sequence, which were assembled in 1 contig. Phylogenetic analysis revealed that the WSSV-GoC18 was closely related to Chinese isolate (WSSV-PC) and distinctly different with previously reported a Korean isolate (WSSV K-LV1). The complete genome sequence of WSSV isolates will be of great help in molecular epidemiological studies, contributing to molecular diagnosis and disease prevention in shrimp aquaculture.

• Journal of Life Science
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• v.20 no.10
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• pp.1427-1432
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• 2010

This study was carried out to evaluate neutralization effects against WSSV using antiserum produced from recombinant envelop protein, rVP466 of WSSV. The VP466 gene of WSSV was cloned into pCold I expression vector and rVP466 was expressed in E. coli RIPL. The antiserum against rVP466 was produced in white rabbits (New Zealand white rabbit). The specific immunoreactivity to the antigen, rVP466, was confirmed by Western blot. The constant amounts of WSSV at $1{\times}10^4$ diluted stocks were mixed with various antiserum concentrations and then injected to the muscle of shrimp, Penaeus chinensis, for the neutralization challenge. The shrimps challenged with WSSV as a positive control and those with the mixture of WSSV and preimmune serum as a preimmune control showed 100% cumulative mortality at 17 days post challenge and 83% at 25 days post challenge, respectively. The shrimps challenged with 3 different mixtures of WSSV and rVP466 antiserum at ratios of 1:0.01, 1:0.1 and 1:1 showed 73%, 53% and 46% cumulative mortalities at 25 days post challenge, respectively. These results indicated that WSSV could be neutralized by the rVP466 antiserum. These results suggest that envelop protein VP466 is involved in the initial step of WSSV infection in shrimp.

• Journal of Life Science
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• v.20 no.8
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• pp.1181-1185
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• 2010

This study was carried out to evaluate the vaccination effects of recombinant fusion protein rVP19+28 against WSSV in shrimp, Litopenaeus vannamei. The VP19+28 gene fused with VP19 and VP28 genes was inserted into pET-28a(+) expression vector and cloned in E. coli BL21 (DE3) to produce fused gene product recombinant VP19+VP28 as a single protein. For the vaccination, the shrimps were fed with pellets coated with purified recombinant protein, rVP19+28, for 2 weeks. Then, constant amounts of WSSV at $1{\times}10^2$ diluted stocks were injected to the muscle of the shrimp for the in vivo challenge tests. Non-vaccinated shrimps showed a cumulative mortality of 100% at 11 days post-challenge. The shrimps vaccinated with the inactivated E. coli BL21 as a host cell control showed cumulative mortality of 100% at 17 days post-challenge. The shrimps vaccinated with rVP19, rVP28 and rVP19+28 showed mortalities of 66.7%, 41.7% and 41.7% at 21 days post-challenge, respectively. These results indicated that the rVP28 and rVP19+28 had relatively high vaccination effects against WSSV infection. However, this study suggests that the fusion protein rVP19+28 was more effective for the protection of shrimp against WSSV than rVP28, even though the cumulative mortalities were the same 21 days post-challenge.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.511-515
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• 2007

White-spot syndrome virus (WSSV) is a devastating, infectious virus affecting shrimp. Although sensitive techniques involving PCR have been developed to assist farmers in screening shrimp (brood stock) for WSSV prior to stocking ponds, such practices have not yet been applied in Korea. Despite the rationality of implementing screening, there has been some doubt as to whether the stocking of WSSV-PCR-negative fly epidemiologically decreases white-spot disease outbreaks. Here, we report a retrospective analysis of data from shrimp farms in the western coast of Korea where WSSV-PCR-negative brood stocks were used to stock rearing ponds. A total of 366 shrimp from Heuksan Island were sampled for WSSV with PCR. Of the tested shrimp, 7.2% (28 brood stocks) were identified as WSSV positive; only WSSV-PCR-negative shrimp were used for brood stocks. Total unit production (final shrimp production/ the area of the ponds) was higher, at 1.96, in ponds where WSSV-PCR-negative shrimp were used, as compared with 1.02 in other ponds in Korea in 2004. This retrospective analysis of WSSV in Korea may be useful to the shrimp aquaculture industry, suggesting a testable hypothesis that may contribute to the eventual control of WSSV outbreaks.

• Journal of fish pathology
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• v.32 no.1
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• pp.45-48
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• 2019

We developed and subsequently characterized mouse monoclonal antibodies (MAbs) against recombinant VP28 structural protein (rVP28) of white spot syndrome virus (WSSV). We established six hybridoma clones secreting MAbs against rVP28: 15A11, 20G6, 31H2, 34H6, 38D1 and 43A1. All six MAbs recognized the 25 kDa of protein in gill homogenates of WSSV-infected shrimp by western blot analysis, while no reactivity was observed in gill homogenates of normal shrimp. Moreover, high enzyme-linked immunosorbent assay (ELISA) optical density (OD) values (0.8-2.68) were observed in the hemolymphs from WSSV-infected shrimp, while low OD values (less than 0.24) were recorded in the hemolymphs from normal shrimp, by using these six MAbs produced in this study. These results suggest that these six MAbs are useful for the detection of WSSV.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.41-41
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• 2003

White spot syndrome virus (WSSV) is the causative agent of a disease that has led to severe mortalities of cultured shrimps in Korea and many other countries. Since 1993, massive mortalities due to the viral infection have also occurred in the penaeid shrimps cultured in Korea. WSSV is a large, circular, double stranded (ds) DNA virus and an enveloped, ellipsoid virus with a rod-shaped nucleocapsid with flat ends. In order to identify the characteristics of this Korean isolate of WSSV, the genes for four virion proteins, VP15, VP19, VP28 and VP35 were cloned and their sequences were compared with the available pool of WSSV gene sequences in the GenBank/EMBL databases. From these comparisons, we confirm the occurrence of WSSV in Korea and deduce that, VP15, VP28 and VP35 genes are identically conserved among the Korean isolate and geographically different foreign isolates, but VP19 amino acid sequences of the Korean WSSV isolates changed valine of the foreign isolates into aspartate. (omitted)

• Journal of Microbiology and Biotechnology
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• v.21 no.2
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• pp.170-175
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• 2011

This study was carried out for the molecular level identification of recombinant protein vaccine efficacy, by oral feeding against white spot syndrome virus infection, with the comparison of viral mRNA transcriptional levels in shrimp cells. For the determination of WSSV dilution ratio for the vaccination experiment by oral feeding, in vivo virus titration was carried out using different virus dilutions of virus stock ($1{\times}10^2$, $2{\times}10^2$, and $1{\times}10^3$). Among the dilution ratios, $2{\times}10^2$ diluted WSSV stock was chosen as the optimal condition because this dilution showed 90% mortality at 10 days after virus injection. Recombinant viral proteins, rVP19 and rVP28, produced as protein vaccines were delivered in shrimps by oral feeding. The cumulative mortalities of the shrimps vaccinated with rVP19 and rVP28 at 21 days after the challenge with WSSV were 66.7% and 41.7%, respectively. This indicates that rVP28 showed a better protective effect against WSSV in shrimp than rVP19. Through the comparison of mRNA transcriptional levels of viral genes from collected shrimp organ samples, it was confirmed that viral gene transcriptions of vaccinated shrimps were delayed for 4~10 days compared with those of unvaccinated shrimps. Protection from WSSV infection in shrimp by the vaccination with recombinant viral proteins could be accomplished by the prevention of entry of WSSV due to the shrimp immune system activated by recombinant protein vaccines.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.69-75
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• 2012

Five-channel electrochemical chips were fabricated based on the Micro-electromechanical System (MEMS) technology and were used as platforms to develop DNA arrays. Different kinds of thiolated DNA strands, whose sequences were related to white spot syndrome virus (WSSV) gene, were separately immobilized onto different working electrodes to fabricate a combinatorial biosensor system. As a result, different kinds of target DNA could be analyzed on one chip via a simultaneous recognition process using potassium ferricyanide as an indicator. To perform quantitative target DNA detection, a limit of 70 nM (S/N=3) was found in the presence of 600 nM coexisting noncomplementary ssDNA. The real samples of loop-mediated isothermal amplification (LAMP) products were detected by the proposed method with satisfactory result, suggesting that the multichannel chips had the potential for a high effective microdevice to recognize specific gene sequence for pointof-care applications.

• Journal of Aquaculture
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• v.15 no.1
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• pp.7-13
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• 2002

Since 1993, the White Spot Syndrome Virus (WSSV) disease occurred in China among cultured shrimps resulting in mass mortality. Epizootiological surveys undertaken during the outbreak period of 1993-1994 indicated that all stages of Penaeus chinensis, P. japonicus and P. monodon were infected. Consequent to the transport of contaminated shrimp seedlings and seawater, the disease spread all over the farms of China. The disease was more rapidly transmitted at temperatures above $25^{\circ}C$. Challenge experiments showed the causative agent was highly virulent. White spots appeared on the carapace of both span-taneous and experimentally infected shrimps. Moribund shrimps contained turbid hemolymph, hypertrophied Iymphoid organ and a necrotic mid-gut gland. Electron microscopy showed the presence of viral particles in the gills, stomach, lymphoid organ, and epidermal tissue of the infected shrimp. The visions were slightly ovoid with an envelope and averaged 350 $\times$ 150 nm; nucleocapsids measured 375 $\times$ 157 nm. With discontinuous sucrose gradient of 35, 50 and 60% (w/v), the virus was separated from hemolymph of the infected shrimp. The estimated molecular weight of genomic DNA was 237 Kb with EcoR I, 247 Kb with Hind III and 241kb with Pst I. A total of 9 hybridoma colones secreting monoclonal antibodies (MAbs) were produced from mouse myeloma and spleen cells immunized with WSSV. The immunofluorescence assay of gill tissue showed that the MAbs reacted with diseased but not with healthy shrimp. The MAbs belonged to IgGl, IgG2b subclass and IgM class, all with kappa light Immune-electron-microscopy with colloidal gold marker showed the presence of 5 MAbs epitopes on the envelope and one on the capsid of the virus. Baculoviral mid-gut gland necrosis showed the specificity of the MAbs produced. For diagnosis 5 different methods were selected. Using Kimura primers for PCR, or MAbs for immunoblot, ELISA or FAT method, in situ hybridization was carried out to show the gene. All these methods detected WSSV in the organ samples of the diseased shrimp but not in healthy one.