• Journal of Microbiology and Biotechnology
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• v.29 no.3
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• pp.482-488
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• 2019

Porcine circovirus type 2 (PCV2) is the causative agent of postweaning multisystemic wasting syndrome (PMWS) in pigs. Replicase (Rep) proteins are considered essential for viral replication. Capsid (Cap) protein is the primary immunogenic protein that induces protective immunity. Little is known about comparison on the immunogenicity of PCV2 Rep and Cap fusion protein and Cap protein. In the present study, recombinant baculoviruses expressing the Rep-Cap fusion protein (Bac-Rep-Cap) and the Cap protein (Bac-Cap) of PCV2 were constructed and confirmed with western blot and indirect fluorescence assay. Immunogenicities of the two recombinant proteins were tested in mice. The titers of antibodies were determined with a PCV2-specific enzyme-linked immunosorbent assay (ELISA) and a serum neutralization assay. The $IFN-{\gamma}$ response of immunized mice was measured by ELISA. The mice immunized with the Bac-Rep-Cap and Bac-Cap successfully produced Cap-specific immunoreaction. The mice immunized with the Bac-Cap developed higher PCV2-specific neutralizing antibody titers than mice injected with the Bac-Rep-Cap. $IFN-{\gamma}$ in the Bac-Rep-Cap group was increased compared to those in the Bac-Cap group. Vaccination of mice with the Bac-Rep-Cap showed significantly decreased protective efficacy compared to the Bac-Cap. Our findings will indubitably not only lead to a better understanding of the immunogenicity of PCV2, but also improved vaccines.

• BMB Reports
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• v.35 no.6
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• pp.562-567
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• 2002

In order to find the cellular interaction factors of the Heliothis armigera nuclear polyhedrosis virus capsid protein VP39, a Heliothis armigera cell cDNA library was constructed. Then VP39 was used as bait. The host actin gene was isolated from the cDNA library with the yeast two-hybrid system. This demonstrated that VP39 could interact with its host actin in yeast. In order to corroborate this interaction in vivo, the vp39 gene was fused with the green fluorescent protein gene in plasmid pEGFP39. The fusion protein was expressed in the Hz-AM1 cells under the control of the Autographa californica multiple nucleopolyhedrovirus immediate early gene promoter. The host actin was labeled specifically by the red fluorescence substance, tetramethy rhodamine isothicyanete-phalloidin. Observation under a fluorescence microscopy showed that VP39, which was indicated by green fluorescence, began to appear in the cells 6 h after being transfected with pEGFP39. Red actin cables were also formed in the cytoplasm at the same time. Actin was aggregated in the nucleus 9 h after the transfection. The green and red fluorescence always appeared in the same location of the cells, which demonstrated that VP39 could combine with the host actin. Such a combination would result in the actin skeleton rearrangement.

• Current Research on Agriculture and Life Sciences
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• v.21
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• pp.11-16
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• 2003

Lines bred for resistance to Phytophthora capsici by incorporation of resistance to P. capsici in PI201234 or CM334 into 'Subi' and 'Chilseong', land races in Youngyang, and 'Punggak', a land race in Cheongdo in Gyeungbuk province, and lines bred for fortification of one of them above with resistance to viral complex, and tolerant selections from another landrace collection from Punggak (KC268) were evaluated for resistance to P. capsici by inoculation at seedling stage. Almost all the breeding lines showed high level of resistance to P. capsid and selections from KC268 showed tolerance or moderate resistance to P. capsid. The selected plants were grown in a net cage in an outdoor nursery for seed production. Utilization of the lines in breeding was discussed.

• Korean Journal of Veterinary Service
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• v.34 no.1
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• pp.1-4
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• 2011

A surface plasmon resonance imaging (SPRI) assay was developed for measuring porcine circovirus type 2 (PCV2) antibody using a recombinant capsid protein as an antigen. The diagnostic potential of SPRI for detecting antibodies to the PCV2 capsid protein was compared with that of a conventional enzyme-linked immunosorbent assay (ELISA) using 70 pig serum samples taken from 6 pig farms. There was a strong positive correlation between the SPRI and ELISA (n = 70, r = 0.911, P<0.01). Therefore, this recombinant capsid protein can be used as an antigen for serological studies, and the SPRI, a label-free and high-throughput method, is expected to be a valuable tool in the serodiagnosis of PCV2 infection.

• Fisheries and Aquatic Sciences
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• v.9 no.4
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• pp.146-152
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• 2006

Systemic infections of maricultured fishes by Megalocytivirus species have occurred over a broad area in South Korea, causing extensive economic loss. We developed digoxigenin-labeled nucleic acid probes against the 230-bp ATPase and 311-bp major capsid protein (MCP) of rock bream Oplegnathus fasciatus iridovirus (RBIV) using polymerase chain reaction, and an in situ hybridization (ISH) method to detect Megalocytivirus in formalin-fixed tissues of mariculture species (rock bream, sea bass, and olive flounder). ISH-positive cells were abundant in the hematopoietic and connective tissues of various organs, while brain tissue showed little or no signal. The ISH procedure can become an important diagnostic tool in complement with histopathological methods, and advances epidemiological studies on the origin and distribution of Megalocytivirus in mariculture.

• Journal of fish pathology
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• v.34 no.2
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• pp.177-184
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• 2021

Vaccines based on single-cycle viruses that are replication-incompetent due to knockout of replication-related structural gene(s) are more immunogenic than inactivated or subunit vaccines and can be used as delivery vehicles for foreign antigens without concerns on the reverting to virulent forms. The aim of this study was to develop a delivery vehicle for nervous necrosis virus (NNV)-like particles (VLPs) using G gene deleted single-cycle VHSV (rVHSV-𝚫G). Recombinant single-cycle VHSVs carrying NNV capsid protein gene between N and P gene of rVHSV-𝚫G genome (rVHSV-𝚫G-NNV_Cap) were rescued by reverse genetic technology. The successful expression of NNV capsid protein in cells infected with rVHSV-𝚫G-NNV_Cap was demonstrated by Western blot analysis, and the production of NNV VLPs in infected cells was confirmed using an electron microscopy. The results suggest that single-cycle VHSVs can be used as a safe delivery vehicle for NNV VLPs, and can be extended to other pathogens for the development of prophylactic vaccines.

• Journal of fish pathology
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• v.33 no.2
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• pp.103-109
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• 2020

In order to use nervous necrosis virus (NNV) virus-like particles (VLPs) as a delivery tool for heterologous antigens or plasmids, we attempted to produce red-spotted grouper nervous necrosis virus (RGNNV) VLPs displaying a partial region of viral hemorrhagic septicemia virus (VHSV) glycoprotein at the surface and VLPs that are harboring DNA vaccine plasmids within the VLP. A peptide encoding 105 amino acids of VHSV glycoprotein was genetically inserted in the loop region of NNV capsid gene, and VLPs expressing the partial part of VHSV glycoprotein were successfully produced. However, in the transmission electron microscope analysis, the shape and size of the partial VHSV glycoprotein-expressing NNV VLPs were irregular and variable, respectively, indicating that the normal assembly of capsid proteins was inhibited by the relatively long foreign peptide (105 aa) on the loop region. To encapsulate by simultaneous transformation with both NNV capsid gene expressing plasmids and DNA vaccine plasmids (having an eGFP expressing cassette under the CMV promoter), NNV VLPs containing plasmids were produced. The encapsulation of plasmids in the NNV VLPs was demonstrated by PCR and cells exposed to the VLPs encapsulating DNA vaccine plasmids showed fluorescence. These results suggest that the encapsulation of plasmids in NNV VLPs can be done with a simple one-step process, excluding the process of disassembly-reassembly of VLPs, and NNV VLPs can be used as a delivery tool for DNA vaccine vectors.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.563-568
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• 2002

Stably transformed Drosophila melanogaster 52 cells producing recombinant VP7 were obtained, and recombinant VP7 expression was confirmed by Western blot analysis. The molecular weight of recombinant VP7 expressed in 52 cells was approximately 35.5 kDa, and 75% of the total VP7 produced was present in the medium. Recombinant VP7 contained N-linked glycosylated oligosaccharides. Aprotinin, leupeptin, and polyvinylpyrrolidone did not have any noticeable effect on recombinant VP7 production; however, DMSO and sodium butyrate increased its production by 120% and 60%, respectively.

• Korean Journal of Veterinary Research
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• v.58 no.3
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• pp.143-146
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• 2018

The capsid protein of porcine circovirus type 2 (PCV2) encoded by open reading frame 2 (ORF2) is important for neutralizing activity against PCV2 infection. This study investigated the heterogeneity of the ORF2 gene of PCV2 isolated in Korea during 2016-2017. The results revealed that PCV2d is currently the predominant genotype. Moreover, comparison of ORF2 from 17 PCV2 isolates revealed 88.3-100% homology at the nucleotide (deduced amino acid 86.3-100%) level. Interestingly, 61.5% (8/13) of the PCV2d isolates had glycine at position 210. These data provide a useful information for PCV2 epidemiology in Korea.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2002.11a
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• pp.139-139
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• 2002

돼지 설사유발 칼리시 바이러스(Porcine enteric calicivirus: PECV)도 자돈에서 설사를 일으키는 바이러스로 이미 알려졌다. RT-PCR과 nested PCR을 이용하여 국내 양돈장에서 PECV의 발생을 조사하고자 본 연구를 시도하였다. 설사 분변은 경기, 충남, 전북, 전남과 제주지역에 분포한 31개의 농장 102마리의 자돈에서 채취하여 의뢰된 것을 조사하였다. RT-PCR 과 nested PCR 을 위하여 RNA dependent RNA Polymerase (RDRP) 부위와 capsid 부위에서 각각 2 쌍의 primer를 작성하였다. RDRP 부위에서 RT-PCR을 시행했던 바, 3마리 (2.9％) 에서, nested PCR에서는 18마리 (17.6％)에서 양성반응이 나왔으며 capsid 부위에서 RT-PCR 결과 5마리 (4.9％), nested PCR에서는 18마리(17.6％)가 양성반응으로 확인되었다. 본 연구를 통하여 PECV가 국내에서 돼지 설사를 일으키는 주요 원인체 중 하나라는 것이 밝혀졌으며, nested PCR 기법이 돼지 설사분변에서 PECV를 검출하는 좋은 진단방법이었다.