• Proceedings of the Microbiological Society of Korea Conference
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• 2000.05a
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• pp.23-36
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• 2000

Japanese encephalitis virus (JEV) is the causative agent of a mosquito-borne encephalitis and is transmitted to human via persistently infected mosquito vectors. Although the virus is known to cause only acute infection, there were reports that showed neurological sequelae, latent infection in peripheral mononuclear cells, and recurrence of the disease after acute encephalitis. Innate resistance of certain cell lines, abnormal SN1 expression of the virus, and anti-apoptotic effect of cullular bcl-2 have been suggested as probable causes of JEV persistence even in the absence of defective interfering (DI) particles. Although possible involvement of DI particles in JEV persistence was suggested, neither has a direct evidence for DI presence nor its molecular characterization been made. Two questions asked in this study are whether the DI virus plays any role in JEV persistent infection if it is associated with and what type of change(s) can be made in persistently infected cells to avoid apoptosis even with the continuous virus replication, DI-free standard stock of JEV was infected in BHK-21, Vero, and SW13 cells and serial high multiplicity passages were performed in order to generate DI particles. There different-sized DI RNA species which were defective in both structural and nonstructural protein coding genes. Rescued ORFs of the DI genome maintained in-frame and the presence of replicative intermediate or replicative form RNA of the DI particles confirmed their replication competence. On the other hand, several clones with JEV persistent infection were established from the cells survived acute infections during the passages. Timing of the DI virus generation during the passages seemed coincide to the appearance of persistently infected cells. The DI RNAs were identified in most of persistently infected cells and were observed throughout the cell maintenance. One of the cloned cell line maintained the viral persistence without DI RNA coreplication. The cells with viral persistence released the reduced but continuous infectious JEV particle for up to 9 months and were refractory to homologous virus superinfection but not to heterologous challenges. Unlike the cells with acute infection these cells were devoid of characteristic DNA fragmentation and JEV-induced apoptosis with or without homologous superinfection. Therefore, the DI RNA generated during JEV undiluted serial passage on mammalian cells was shown to be biologically active and it seemed to be responsible, at least in part, for the establishment and maintenance of the JEV persistence in mammalian cells. Viral persistence without DI RNA coreplication, as in one of the cell clones, supports that JEV persistent infection could be maintained with or without the presence of DI particles. In addition, the fact that the cells with JEV persistence were resistant against homologous virus superinfection, but not against heterologous one, suggests that different viruses have their own and independent pathway for cytopathogenesis even if viral cytopathic effect could be converged to an apoptosis after all.

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.10b
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• pp.254-255
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• 2005

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.381-381
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• 2005

• Proceedings of the Korean Society of Crop Science Conference
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• 1992.05a
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• pp.14-15
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• 1992

• International Journal of Industrial Entomology and Biomaterials
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• v.13 no.1
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• pp.31-35
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• 2006

The ubiquitin conjugating enzyme 2 (E2) is core component of ubiquitin proteasome pathway (UPP) which represents a selective mechanism for intracellular proteolysis in eukaryotic cells. The E2 has been implicated in the intracellular transfer of ubiquitin to target protein. We show here the involvement of E2 in antiviral immune of Bombyx mori to Bombyx mori nuclear polyhedrosis virus (BmNPV). In this study, mRNA fluorescent differential display PCR (FDD-PCR) was performed with BmNPV highly resistant silkworm strain NB and susceptible silkworm strain 306. At 24 h post BmNPV infection, FDD-PCR with the arbitrary primer AP34 showed that one cDNA band was down-regulated in the midgut of resistant strain, but highly expressed in susceptible strain. The deduced amino acid sequence of this cDNA clone share 99% identity with the recently published B. mori ubiquitin conjugating enzyme E2 (Genbank NO: DQ311351). Fluorescent quantitative PCR corroborated down regulation of E2 in resistant strain. We there conclude that BmNPV infection evokes strong response of susceptible strain including activation of UPP. BmNPV may evolve escape mechanisms that manipulate the UPP in order to persist in the infected host. In addition, the identification of down-regulation of E2 in resistant strain, as well as structure data, are essential to understanding how UPP operates in silkworm antiviral immune to BmNPV disease.

• Journal of Veterinary Science
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• v.24 no.1
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• pp.13.1-13.11
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• 2023

Background: Highly pathogenic avian influenza viruses (HPAIVs) is an extremely contagious and high mortality rates in chickens resulting in substantial economic impact on the poultry sector. Therefore, it is necessary to elucidate the pathogenic mechanism of HPAIV for infection control. Objective: Gene set enrichment analysis (GSEA) can effectively avoid the limitations of subjective screening for differential gene expression. Therefore, we performed GSEA to compare HPAI-infected resistant and susceptible Ri chicken lines. Methods: The Ri chickens Mx(A)/BF2(B21) were chosen as resistant, and the chickens Mx(G)/BF2(B13) were selected as susceptible by genotyping the Mx and BF2 genes. The tracheal tissues of HPAIV H5N1 infected chickens were collected for RNA sequencing followed by GSEA analysis to define gene subsets to elucidate the sequencing results. Results: We identified four differentially expressed pathways, which were immune-related pathways with a total of 78 genes. The expression levels of cytokines (IL-1β, IL-6, IL-12), chemokines (CCL4 and CCL5), type interferons and their receptors (IFN-β, IFNAR1, IFNAR2, and IFNGR1), Jak-STAT signaling pathway genes (STAT1, STAT2, and JAK1), MHC class I and II and their co-stimulatory molecules (CD80, CD86, CD40, DMB2, BLB2, and B2M), and interferon stimulated genes (EIF2AK2 and EIF2AK1) in resistant chickens were higher than those in susceptible chickens. Conclusions: Resistant Ri chickens exhibit a stronger antiviral response to HPAIV H5N1 compared with susceptible chickens. Our findings provide insights into the immune responses of genetically disparate chickens against HPAIV.

• Plant Breeding and Biotechnology
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• v.7 no.3
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• pp.272-286
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• 2019

Developing elite hybrid rice varieties is one important objective of rice breeding programs. Several genes related to male sterilities, restores, and pollinators have been identified through map-based gene cloning within natural variations of rice. These identified genes are good targets for introducing genetic traits in molecular breeding. This study was conducted to breed elite hybrid lines with major genes related to hybrid traits and disease/insect resistance in 240 genetic resources and F₁ hybrid combinations of rice. Molecular markers were reset for three major hybrid genes (S5, Rf3, Rf4) and thirteen disease/insect resistant genes (rice bacterial blight resistance genes Xa3, Xa4, xa5, Xa7, xa13, Xa21; blast resistance genes Pita, Pib, Pi5, Pii; brown planthopper resistant genes Bph18(t) and tungro virus resistance gene tsv1). Genotypes were then analyzed using molecular marker-assisted selection (MAS). Biological assay was then performed at the Red River Delta region in Vietnam using eleven F₁ hybrid combinations and two control vatieties. Results showed that nine F₁ hybrid combinations were highly resistant to rice bacterial blight and blast. Finally, eight F₁ hybrid rice varieties with resistance to disease/insect were selected from eleven F₁ hybrid combinations. Their characteristics such as agricultural traits and yields were then investigated. These F₁ hybrid rice varieties developed with major genes related to hybrid traits and disease/insect resistant genes could be useful for hybrid breeding programs to achieve high yield with biotic and abiotic resistance.

• Korean journal of applied entomology
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• v.5_6
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• pp.47-54
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• 1968

In order to develop an effective control measure for the rice stripe disease, methods of testing for resistance and selection of resistant varieties among the leading varieties were investigated. For use as a parent in breeding for resistant variety to the disease, total of 410 rice varieties were tested. 1. Disease occurrence was higher at group inoculation than that of individual inoculation in comparing the inoculation methods. 2. In both methods, Lacrose responded susceptible; Zenith and St. No. 1 resistant, and the rest moderate. 3. Suseptible symptom type A was prevalant among the susceptible varieties, while resistant symptom type C was abundant among the resistant varieties, There was no difference between the inoculation methods. 4. 410 rice varieties tested could he divided into 3 groups as susceptible (21 varieties), moderate (377 varieties) and resistant (12 varieties). Resistant varieties wers St. No. 1 and 2, Shin-2, Gulfrose Bonnet, Arkrose, Sun Bonnet, Zenith, Yeechunchilichal, Norm-24, Opaikjoke, Yangchubatchal and Nonglimana-1, Nams-97,-149, -159, -216. -265, Iri-243, -265, Kanchuk -5, -7, -8, -10, -41, -43, -47, -50, Suwon-56, -77, Norin-22, Cod-4. Lacrose and Chukna were susceptible. 5. There was slight differance in the disease occurrence in regard to maturing period. However late varieties seem to be more resistant than early or medium varieties. The medium varieties seem to be susceptible. Most of the introduced varieties from foreign countries and the upland cultivated varieties were resistant. 6 Among the leading varieties, Shin-2 in Kangwon-Do was resistant, Kosi in Choongchung-Do, was susceptible, aad the others were moderate.

• Research in Plant Disease
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• v.23 no.1
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• pp.60-64
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• 2017

Leaves of twenties radish (Raphanus sativus L.) inbred lines were mechanically inoculated with Turnip mosaic virus (TuMV) strain HY to evaluate TuMV resistance of the radish inbred lines. The inoculated radish plants were incubated at $22^{\circ}C{\pm}3^{\circ}C$ and resistance assessment was examined using symptom development for 4 weeks. Based on the reactions of differential radish inbred lines, 16 radish lines were produced mild mosaic, mottling, mosaic and severe mosaic symptoms by TuMV infection. These results were confirmed by RT-PCR analysis of TuMV coat protein gene, suggesting that TuMV is responsible for the disease symptoms. Four resistant radish lines did not induce systemic mosaic symptoms on upper leaves and chlorosis in stem tissues for 4 weeks, showing they were symptomless by 8 weeks. Further examination of TuMV infection in the 4 radish lines showed no TuMV infection in all systemic leaves. These results suggest that the 4 radish lines are highly resistant to TuMV.

• Journal of Veterinary Science
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• v.24 no.5
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• pp.73.1-73.16
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• 2023

Background: Highly pathogenic avian influenza virus (HPAIV) is considered a global threat to both human health and the poultry industry. MicroRNAs (miRNA) can modulate the immune system by affecting gene expression patterns in HPAIV-infected chickens. Objectives: To gain further insights into the role of miRNAs in immune responses against H5N1 infection, as well as the development of strategies for breeding disease-resistant chickens, we characterized miRNA expression patterns in tracheal tissues from H5N1-infected Ri chickens. Methods: miRNAs expression was analyzed from two H5N1-infected Ri chicken lines using small RNA sequencing. The target genes of differentially expressed (DE) miRNAs were predicted using miRDB. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis were then conducted. Furthermore, using quantitative real-time polymerase chain reaction, we validated the expression levels of DE miRNAs (miR-22-3p, miR-146b-3p, miR27b-3p, miR-128-3p, miR-2188-5p, miR-451, miR-205a, miR-203a, miR-21-3p, and miR-200a3p) from all comparisons and their immune-related target genes. Results: A total of 53 miRNAs were significantly expressed in the infection samples of the resistant compared to the susceptible line. Network analyses between the DE miRNAs and target genes revealed that DE miRNAs may regulate the expression of target genes involved in the transforming growth factor-beta, mitogen-activated protein kinase, and Toll-like receptor signaling pathways, all of which are related to influenza A virus progression. Conclusions: Collectively, our results provided novel insights into the miRNA expression patterns of tracheal tissues from H5N1-infected Ri chickens. More importantly, our findings offer insights into the relationship between miRNA and immune-related target genes and the role of miRNA in HPAIV infections in chickens.