• Korean Journal of Veterinary Service
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• v.35 no.3
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• pp.169-174
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• 2012

Japanese encephalitis virus (JEV) is one of the main causes of viral encephalitis in human and animals. For over 30 years, a live attenuated JEV vaccine strain has been used in the veterinary field, and it is required to conduct quality evaluation studies on the commercial vaccines. For the quality control of live attenuated JEV vaccine, we investigated the nucleotide sequence similarity of prME gene derived from five JEV vaccines commercially available in pigs in Korea. The Vero cells infected with JEV vaccines showed specific cytopathic effect, which was characterized by rounding and detached cells. In the phylogenetic analysis, all of the vaccine strains showed a close relationship with the original vaccine seed strain (Anyang 300) and clustered into the genotype 3. In comparison of the nucleotide and deduced amino acid sequences of prME genes with the original strain, all JEV vaccine strains showed high amino acid similarity ranging from 98.9% to 99.5%, but had several point mutations, probably due to high mutation rates of viral RNA polymerase by several virus passages. Even though the current JEV vaccine strains have been maintained and produced for a long period of time, the genetic characterization of them have been rarely changed. However, since the mid 1990's, molecular epidemiology of JEV has been changed sharply from genotype 3 to genotype 1 in Korea, further studies on new vaccine strains to genotype 1 is required for more effective prevention in the field.

• Journal of Microbiology
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• v.43 no.6
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• pp.529-536
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• 2005

Viral infection causes stress to the endoplasmic reticulum (ER). The response to endoplasmic reticulum stress, known as the unfolded protein response (UPR), is designed to eliminate misfolded proteins and allow the cell to recover. The role of hepatitis C virus (HCV) non-structural protein NS4B, a component of the HCV replicons that induce UPR, is incompletely understood. We demonstrate that HCV NS4B could induce activating transcription factor (ATF6) and inositol-requiring enzyme 1 (IRE1), to favor the HCV subreplicon and HCV viral replication. HCV NS4B activated the IRE1 pathway, as indicated by splicing of X box-binding protein (Xbp-1) mRNA. However, transcriptional activation of the XBP-1 target gene, EDEM (ER degradation-enhancing $\alpha-mannosidase-like$ protein, a protein degradation factor), was inhibited. These results imply that NS4B might induce UPR through ATF6 and IRE1-XBP1 pathways, but might also modify the outcome to benefit HCV or HCV subreplicon replication.

• Fisheries and Aquatic Sciences
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• v.21 no.3
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• pp.5.1-5.8
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• 2018

Stimulator of interferon gene (STING) is induced by various inflammatory agents, such as lipopolysaccharide and microbial pathogens, including virus and bacteria. In this study, we obtained a full-length cDNA of a STING homolog from olive flounder using rapid amplification of cDNA ends PCR technique. The full-length cDNA of Paralichthys olivaceus STING (PoSTING) was 1442 bp in length and contained a 1209-bp open reading frame that translated into 402 amino acids. The theoretical molecular mass of the predicted protein sequence was 45.09 kDa. In the PoSTING protein, three transmembrane domains and the STING superfamily domain were identified as characteristic features. Quantitative real-time PCR revealed that PoSTING expressed in all the tissues analyzed, but showed the highest level in the spleen. Temporal expression analysis examined the significantly upregulated expression of PoSTING mRNA after viral hemorrhagic septicemia virus (VHSV) stimulation. In contrast, no significant changes in the PoSTING expression were detected in Edwardsiella tarda-challenged group compared to the un-injected control. The expression of P. olivaceus type I interferon (PoIFN-I) was also highly upregulated upon VHSV challenge. These results suggest that STING might be involved in the essential immune defense against viral infection together with the activation of IFN-I in olive flounder.

• Genomics & Informatics
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• v.14 no.3
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• pp.104-111
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• 2016

Zika virus (ZIKV) is a mosquito borne pathogen, belongs to Flaviviridae family having a positive-sense single-stranded RNA genome, currently known for causing large epidemics in Brazil. Its infection can cause microcephaly, a serious birth defect during pregnancy. The recent outbreak of ZIKV in February 2016 in Brazil realized it as a major health risk, demands an enhanced surveillance and a need to develop novel drugs against ZIKV. Amodiaquine, prochlorperazine, quinacrine, and berberine are few promising drugs approved by Food and Drug Administration against dengue virus which also belong to Flaviviridae family. In this study, we performed molecular docking analysis of these drugs against nonstructural 3 (NS3) protein of ZIKV. The protease activity of NS3 is necessary for viral replication and its prohibition could be considered as a strategy for treatment of ZIKV infection. Amongst these four drugs, berberine has shown highest binding affinity of -5.8 kcal/mol and it is binding around the active site region of the receptor. Based on the properties of berberine, more similar compounds were retrieved from ZINC database and a structure-based virtual screening was carried out by AutoDock Vina in PyRx 0.8. Best 10 novel drug-like compounds were identified and amongst them ZINC53047591 (2-(benzylsulfanyl)-3-cyclohexyl-3H-spiro[benzo[h]quinazoline-5,1'-cyclopentan]-4(6H)-one) was found to interact with NS3 protein with binding energy of -7.1 kcal/mol and formed H-bonds with Ser135 and Asn152 amino acid residues. Observations made in this study may extend an assuring platform for developing anti-viral competitive inhibitors against ZIKV infection.

• Entomological Research
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• v.48 no.5
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• pp.384-389
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• 2018

Aphis gossypii Glover is an important insect pest that functions as a viral vector and mediates approximately 45 different viral diseases. As part of a strategy for control of A. gossypii, we investigated the functions of genes using RNAi. To this end, a cDNA library was constructed for various genes and for selecting appropriate targets for RNAi mediated silencing. The cDNA library was constructed using the Gateway cloning system with site-specific recombination of bacteriophage ${\lambda}$. It was used to carry out single step cloning of A. gossypii cDNAs. As a result, a cDNA library with a titer of $8.4{\times}10^6$ was constructed. Since the sequences in this library carry att sites, they can be cloned into various binary vectors. This library will be of value for various studies. For later screening of selected genes, it is planned to clone the library into virus-induced gene silencing (VIGS) vectors, which makes it possible to analyze gene function and allow subsequent transfection of plants. Such transfection experiments will allow testing of RNAi-induced insecticidal activity or repellent activity to A. gossypii, and result in the identification of target genes. It is also expected that the constructed cDNA library will be useful for analysis of gene functions in A. gossypii.

• Journal of Microbiology and Biotechnology
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• v.31 no.12
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• pp.1709-1715
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• 2021

Outbreaks of food poisoning due to the consumption of norovirus-contaminated shellfish continue to occur. Male-specific (F+) coliphage has been suggested as an indicator of viral species due to the association with animal and human wastes. Here, we compared two methods, the double agar overlay and the quantitative real-time PCR (RT-PCR)-based method, for evaluating the applicability of F+ coliphage-based detection technique in microbial contamination tracking of shellfish samples. The RT-PCR-based method showed 1.6-39 times higher coliphage PFU values from spiked shellfish samples, in relation to the double agar overlay method. These differences indicated that the RT-PCR-based technique can detect both intact viruses and non-particle-protected viral DNA/RNA, suggesting that the RT-PCR based method could be a more efficient tool for tracking microbial contamination in shellfish. However, the virome information on F+ coliphage-contaminated oyster samples revealed that the high specificity of the RT-PCR- based method has a limitation in microbial contamination tracking due to the genomic diversity of F+ coliphages. Further research on the development of appropriate primer sets for microbial contamination tracking is therefore necessary. This study provides preliminary insight that should be examined in the search for suitable microbial contamination tracking methods to control the sanitation of shellfish and related seawater.

• Clinical and Experimental Vaccine Research
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• v.12 no.4
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• pp.265-290
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• 2023

Rare but serious thrombotic incidents in relation to thrombocytopenia, termed vaccine-induced immune thrombotic thrombocytopenia (VITT), have been observed since the vaccine rollout, particularly among replication-defective adenoviral vector-based severe acute respiratory syndrome coronavirus 2 vaccine recipients. Herein, we comprehensively reviewed and summarized reported studies of VITT following the coronavirus disease 2019 (COVID-19) vaccination to determine its prevalence, clinical characteristics, as well as its management. A literature search up to October 1, 2021 using PubMed and SCOPUS identified a combined total of 720 articles. Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guideline, after screening the titles and abstracts based on the eligibility criteria, the remaining 47 full-text articles were assessed for eligibility and 29 studies were included. Findings revealed that VITT cases are strongly related to viral vector-based vaccines, which are the AstraZeneca COVID-19 vaccine (95%) and the Janssen COVID-19 vaccine (4%), with much rarer reports involving messenger RNA-based vaccines such as the Moderna COVID-19 vaccine (0.2%) and the Pfizer COVID-19 vaccine (0.2%). The most severe manifestation of VITT is cerebral venous sinus thrombosis with 317 cases (70.4%) and the earliest primary symptom in the majority of cases is headache. Intravenous immunoglobulin and non-heparin anticoagulant are the main therapeutic options for managing immune responses and thrombosis, respectively. As there is emerging knowledge on and refinement of the published guidelines regarding VITT, this review may assist the medical communities in early VITT recognition, understanding the clinical presentations, diagnostic criteria as well as its management, offering a window of opportunity to VITT patients. Further larger sample size trials could further elucidate the link and safety profile.

• The Plant Pathology Journal
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• v.16 no.5
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• pp.269-279
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• 2000

Alfalfa mosaic alfamoviruses(AIMV) were isolated from infected potato (Solanum tuberosum) and azuki bean (Paseolus angularis) in Korea. Two AIMV isolated from potatoes were named as strain KR (AIMV-KR1 and KR2) and AIMV isolated from azuki bean was named as strain Az (AIMV-Az). Each isolated AIMV strain was characterized by using their host ranges, symptom developments, serological relations and nucleotide sequence analysis of coat protein (CP) gene. Strains KR1, KR2, and Az were readily transmitted to 20 of 22 inoculated plant species including bean, cowpea, tomato, tobacco, and potato. AIMV-KR1 and KR2 produced the typical symptoms like chlorotic or necrotic spots in Chenopodium quinoa and Solanum tuberosum cv. Superior. AIMV-Az caused bright yellow mosaic symptom and leaf malformation in Nicotiana glauca, which were different from the common mosaic symptom caused by AIMV-KR1 and KR2. Electron microscope observation of purified virus showed bacilliform virions containing a single-stranded plus-strand RNAs of 3.6, 2.6, 2.0 and 0.9 kbp in length, respectively, similar in size and appearance to those of Alfamovirus. In SDS-PAGE, the coat protein of the two viruses formed a consistent band that estimated to be about 24kDa. The CP genes of the AIMV strains, KR1, KR2, and Az have been amplified by RT-PCR using the specific primers designed to amplify CP gene from viral RNA-3, cloned and sequenced. Computer aided analysis of the amplified cDNA fragment sequence revealed the presence of a single open reading frame capable of encoding 221 amino acids. The nucleotide and peptide sequence of viral CP gene showed that strain KR1, KR2, and Az shared highest nucleotide sequence identities with AIMV strain 425-M at 97.7%, 98.2%, and 97.2%, respectively. CP gene sequences of two strains were almost identical compared with each other. Altogether, physical, serological, biological and molecular properties of the purified virus.

• Korean Journal of Food Science and Technology
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• v.37 no.6
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• pp.1018-1023
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• 2005

Simplified procedure was developed for concentrating and detecting poliovirus and norovirus in oysters. Viruses were seeded into oyster tissue homogenates and concentrated through polyethylene glycol (PEG) precipitation, chloroform or Freon extraction, with additional PEG precipitation. Amount of viruses was evaluated using poliovirus plaque assay. Virus recovery during concentration procedure was approximately 16.4-26.0%. For defection, viral RNAs in oysters were examined using one-step RT-PCR after extraction with Trizol. Dilution or capturing of viral RNA using silica gel membrane allowed viruses to be detected by RT-PCR, whereas viruses could not be removed using $QIAshredder^{TM}$ Homogenizer, which is effective in removing RT-PCR inhibitors in lettuce and hamburgers. Freon extraction, generally used to concentrate viruses found in food, could be substituted with chloroform extraction using this procedure; no difference could be observed between detection limits of whole oyster extracts and digestive organ extracts indicating that RT-PCR inhibitors were distributed evenly throughout whole tissues. Nested PCR greatly improved efficiency of this procedure. Overall, this procedure could remove sufficient amount of inhibitors to allow detection of norovirus in oysters.

• Journal of fish pathology
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• v.23 no.3
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• pp.335-342
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• 2010

In 2008, mass mortality was observed in paradise fish Macropodus opercularis which was imported from Indonesia. PCR of these fish found positive for megalocytivirus and Mycobacterium sp., while an unidentified virus was culture-isolated using CHSE-214 cells. In the present study, we investigated characterization of the unidentified virus and its pathogenicity to determine whether the virus was the causative agent of the mass mortality of paradise fish. The unidentified virus induced cytopathic effect (CPE) with syncytia in CHSE-214 and other fish cells, BF-2, GF, SSN-1, FSP and FFN. The virus was resistant against treatments with IUdR, chloroform, acidity at pH 3, basicity at pH 11 and high temperature at $56^{\circ}C$ for 3h. By electron microscopy, the viral particles were spherical having a double capsid structure with approximately 65 nm in external diameter. Viral genome was composed of at least 10-segmented RNA with sizes ranging from 0.7 kb to 3.6 kb. Based on these characters, this virus can be classified into family Reoviridae. This reovirus did not cause any mortality in an artificial experiment conducted by injecting the virus to paradise fish. This indicates that the reovirus is not only responsible for the mass mortality of paradise fish in 2008.