• Korean Journal of Pharmacognosy
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• v.48 no.3
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• pp.173-178
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• 2017

We investigated the efficacy of single compound of plant extract in coxsackievirus B3 (CVB3) infection. CVB3 is a main cause of Hand-foot-mouth diseases (HFMD) and viral myocarditis in children and adult. Several single compounds of plant extract were purified by HPLC and tested as antiviral drug candidate. Among them, kaempferol was selected to effective anti-enterovirus compound by HeLa cells survival assay. CVB3 infected HeLa cells were treated with kaempferol ($100{\mu}g/ml-100ng/ml$) and their antiviral effect was confirmed. After 16 hours of treatment, HeLa cells were lysed and proteins were extracted for western blot analysis. CVB3 viral capsid protein VP1 production and transcription factor eIF4G-1 cleavage was significantly decreased in $100{\mu}g/ml$ kaempferol treatment. Virus replication was observed by virus RNA amplification. Kaempferol strongly reduced virus positive and negative strand RNA amplification. Moreover, MAPK signal induced by CVB3 infection, pERK and pmTOR, kaempferol treatment significantly inhibited the activity. Plant extract single compound, kaempferol, is a strong candidate to be developed non-toxic anti-enterovirus treatment agent.

• Animal cells and systems
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• v.3 no.3
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• pp.337-341
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• 1999

Hepatitis C virus (HCV) is a positive strand RNA virus of the Flaviviridae family and the major cause of post-transfusion non-A, non-B hepatitis. Vaccine development for HCV is essential but has been slowed by poor understanding of the type of immunity that naturally terminates HCV infection. The DNA-based immunization technique offers the potential advantage of including cellular immune responses against conserved internal proteins of a virus, as well as the generation of antibodies to viral surface proteins. Here, we demonstrate that cell lines expressing the HCV core and/or NS3 proteins can induce a specific CTL response in mice, and these results suggest a possibility that the HCV core and NS3 DNA can be used to induce CTL activity against the antigen in mice and can be further developed as a therapeutic and preventive DNA vaccine.

• Korean Journal of Veterinary Service
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• v.42 no.1
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• pp.9-15
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• 2019

Transmissible gastroenteritis (TGE) is a disease confined to pigs of all ages, and can be a significant cause of economic loss in breeding herds, primarily because of the very high piglet mortality. The causative agent is a coronavirus, an enveloped positive strand RNA virus and closely related but non-enteropathogenic porcine respiratory coronavirus (PRCV). Although the TGEV has declined with its innocent relative, PRCV, further genome changes could not be excluded. Therefore, the herd-level immunity against this virus is important for the prevention of disease and should be carefully monitored. The aim of this study is to develop monoclonal antibody capture enzyme-linked immunosorbent assay (MAC-ELISA) which can rapidly and accurately determine a large numbers of serum samples for surveillance purpose, and to compare the ELISA with a TGEV-specific serum neutralization test. The MAC-ELISA was sufficiently achieved, and the comparison with the virus-specific serum neutralization assays for 713 sera from pig farms showed a high correlation ($r^2=0.812$, P<0.001). The specificity and sensitivity of MAC-ELISA for the serum neutralization test 91.9% and 91.6%, respectively, which means that the antibody detected by the MAC-ELISA could be said to be protective antibodies. In conclusion, the developed MAC-ELISA would be very helpful in evaluating protective antibodies against TGEV.

• Applied Biological Chemistry
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• v.38 no.1
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• pp.49-54
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• 1995

To understand the molecular structure and pathogenesis mechanism of Korean garlic viruses, we have isolated cDNA clones for garlic viruses. The partial nucleotide sequences of 24 cDNA clones were determined and those of five clones containing poly(A) tail were compared with sequences of other plant viruses. One of these clones, V9, has a primary structure similar to the carlavirus group, suggesting that the clone V9 derived from a part of garlic latent virus (GLV). Northern blot analysis with the clone V9 as a probe demonstrated that GLV genome is 8.5 knt long and has a poly(A) tail. The clone V9 encodes coat protein (CP) of 33 kDa and nucleic acid binding protein of 10 kDa in different reading frame. The hexanucleotide motif, 5'-ACCUAA, which is conserved in the 3' noncoding region arid was proposed to be a cis-acting element involved in the production of negative strand genomic RNA was noticed. Complementary sequence to the hexanucleotide motif, 5'-TTAGGT, is also found in the positive strand of V9 RNA. The putative CP gene was cloned into the pRSET-A expression vector and expressed in E. coli BL21. The expressed recombinant V9CP protein was purified by $Ni^{2+}$ NTA affinity chromatography. The anti-V9CP antibody recognizes 34 kDa polypeptide which could be CP of GLV in infected garlic leaf extract. Immunoblot and Northern blot analysis of various cultivars shows wide occurrence of GLV in Korean garlic plants.

• Korean Journal of Pharmacognosy
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• v.47 no.2
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• pp.137-142
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• 2016

Enterovirus is a common cause of several severe diseases such as myocarditis, hand-foot-mouth disease, and meningitis in children and adult. There are many try to develop new antiviral drug for direct treatment in virus infection. However, synthetic chemical antiviral drug is not working. To overcome this limitation, we examined plant extracts. The antiviral effect of plant extracts was screened by HeLa cell survival assay in coxsackievirus B3 (CVB3) infection. We observed a strong antiviral effect of Poria cocos extract in a dose-dependent manner (1 mg/ml~0.01 mg/ml). P. cocos extract (1 mg/ml) treatment was dramatically decreased virus protease 2A induced eIF4G-I cleavage and virus capsid protein VP1 production. CVB3 positive and negative strand RNA amplification were significantly reduced in P. cocos extract treatment. P. cocos extract completely blocked early time activation of ERK and AKT activity in CVB3 infection. Taken together these data indicate that the treatment of P. cocos extract strongly inhibit CVB3 replication. Poria cocos extract may possible to developed as a therapeutic agent for enterovirus.

• Bulletin of the Korean Chemical Society
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• v.20 no.3
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• pp.301-306
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• 1999

Hepatitis C virus (HCV) has been known to be an enveloped virus with a positive strand RNA genome and the major agent of the vast majority of transfusion associated cases of hepatitis. For viral replication, HCV structural proteins are first processed by host cell signal peptidases and NS2/NS3 site of the nonstructural protein is cleaved by a zinc-dependent protease NS2 with N-terminal NS3. The four remaining junctions are cleaved by a separate NS3 protease. The solution conformations of NS4B/5A, NS5A/5B substrates and NS5A/5B inhibitor have been determined by two-dimensional nuclear magnetic resonance (NMR) spectroscopy. NMR data suggested that the both NS5A/5B substrate and inhibitor appeared to have a folded tum-like conformation not only between P1 and P6 position but also C-terminal region, whereas the NS4B/5A substrate exhibited mostly extended conformation. In addition, we have found that the conformation of the NS5A/5B inhibitor slightly differs from that of NS5A/5B substrate peptide, suggesting different binding mode for NS3 protease. These findings will be of importance for designing efficient inhibitor to suppress HCV processing.

• Korean Journal of Ecology and Environment
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• v.54 no.3
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• pp.190-198
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• 2021

Human Aichivirus (Aichivirus A; AiV-A) is a positive-sense single-strand RNA non-enveloped virus that has been detected worldwide in various water environments including sewage, river, surface, and ground over the past decade. To develop a method with excellent sensitivity and specificity for AiV-A diagnosis from water environments such as groundwater, a combination capable of reverse transcription (RT)-nested polymerase chain reaction (PCR) was developed based on existing reported and newly designed primers. A selective method was applied to evaluate domestic drinking groundwater samples. Thus, a procedure was devised to select and subsequently identify RT-nested PCR primer sets that can successfully detect and identify AiV-A from groundwater samples. The findings will contribute to developing a better monitoring system to detect AiV-A contamination in water environments such as groundwater.

• The Journal of Korean Society of Virology
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• v.27 no.2
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• pp.185-195
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• 1997

Sequence comparison of the RNA-dependent RNA polymerase of human caliciviruses (HuCVs) from Korean children with gastroenteritis revealed significant genetic variation among them. cDNA clones were produced from the HuCVs collected from pediatric population during a period of 1987-1994. The application of reverse transcription-polymerase chain reaction (RT-PCR) using primers directed to the RNA-dependent RNA polymerase region within ORF1 of Norwalk virus (NV) showed that 13.7% of HuCVs yielded PCR products of similar size to the NV prototype, NV8FIIa/68/US, with exceptions of HuCV 185/87/Korea and HuCV 1115/90/Korea. Computer analyses showed that the PCR products had a continuous protein encoding frame on the positive strand, and contained GLPSG and YGDD amino acid motifs at the predicted distance from primers. Alignment of the amino acid sequences of HuCVs with previously published sequences for Snow Mountain agent (SMA), NV, and Sapporo/82/Japan indicated that these strains can be divided into four major genogroups. There were 10 (45%) SMA-like CVs, one (4.5%) NV-like HuCVs, two (9%) Sapporo-like HuCVs, and nine (41%) unidentified HuCVs. This fourth genogroup should be investigated further. HuCV 185/87/Korea and HuCV 1115/90/Korea, Sapporo-like CVs, were genetically distinct from previously characterized HuCVs and more closely related to known animal CVs. One of the animal CV-like strain, HuCV 185/87/Korea, showed nucleotide and amino acid homology of only 67% and 73% with the prototype Sapporo/82/Japan. Further characterization of animal and human CV genomes and studies of possible cross-transmission of CVs from animals to humans are likely to be beneficial in understanding the epidemiology of HuCVs.

• Journal of Life Science
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• v.30 no.3
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• pp.285-290
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• 2020

Foot-and-mouth disease virus (FMDV), a member of the genus Aphthovirus in the Picornaviridae family, affects wild and domesticated ruminants and pigs. FMDV causes various clinical symptoms, including severe inflammation in infected tissue. Genome RNA of FMDV shows a positive single-strand chain approximately 8.3 kb long and encodes a single long open reading frame (ORF). The ORF is translated into structural and non-structural proteins by viral proteases. The FMDV 2C protein is one of the non-structural proteins encoded by FMDV and plays a critical role in FMD pathogenesis, including inflammation, apoptosis, and viral replication. In this study, we examined whether FMDV 2C induces intracellular expression of pro-inflammatory cytokine tumor necrosis factor alpha (TNFα). FMDV 2C expression in pig IBRS-2 cells increased mRNA and protein expression of TNFα at the transcriptional level via activation of TNFα promoter. Treatment with 4-phenylbutyric acid, an endoplasmic reticulum (ER) stress reducer, decreased TNFα expression induced by FMDV 2C. Activating transcription factor 4 (ATF4), a transcription factor mediating ER stress response, induced transactivation of TNFα promoter and expression of mRNA and protein of TNFα. However, the dominant negative mutant of ATF4 did not induce FMDV 2C-mediated TNFα expression. The results indicate that FMDV 2C protein increases clinical inflammation via ATF4-mediated TNFα expression and is associated with ER stress induction.