• Korean journal of applied entomology
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• v.12 no.3
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• pp.93-107
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• 1973

Garlic (Allium sativum L.) is an important vegetable crop for the Korean people and has long been cultivated extensively in Korea. More recently it has gained importance as a source of certain pharmaceuticals. This additional use has also contributed to the increasing demand for Korean garlic. Garlic has been propagated vegetatively for a long time without control measures against virus diseases. As a result it is presumed that most of the garlic varieties in Korea may have degenerated. The production of virus-free plants offers the most feasible way to control the virus diseases of garlic. However, little is known about garlic viruses both domestically and in foreign countries. More basic information regarding garlic viruses is needed before a sound approach to the control of these diseases can be developed. Currently garlic mosaic disease is most prevalent in plantings throughout Korea and is considered to be the most important disease of garlic in Korea. Because of this importance, studies were initiated to isolate and characterize the garlic mosaic virus. Symptom expression in test plants, physical properties, purification, serological reaction and morphological characteristics of the garlic mosaic virus were determined. Results of these studies are summarized as follows. 1. Surveys made throughout the important garlic growing areas in Korea during 1970-1972 revealed that most of the garlic plants were heavily infected with mosaic disease. 2. A strain of garlic mosaic virus was obtained from infected garlic leaves and transmitted mechanically to Chenopodium amaranticolor by single lesion isolation technique. 3. The symptom expression of this garlic mosaic virus isolate was examined on 26 species of test plants. Among these, Chenopodium amaranticolor, C. quince, C. album and C. koreanse expressed chlorotic local lesions on inoculated leaves 11-12 days after mechanical inoculation with infective sap. The remaining 22 species showed no symptoms and no virus was recovered from them whet back-inoculated to C. amaranticolor. 4. Among the four species of Chtnopodium mentioned above, C. amaranticolor and C. quinoa appear to be the most suitable local lesion test plants for garlic mosaic virus. 5. Cloves and top·sets originating from mosaic infected garlic plants were $100\%$ infected with the same virus. Consequently the garlic mosaic virus is successively transmitted through infected cloves and top-sets. 6. Garlic mosaic virus was mechanically transmitted to C, amaranticolor when inoculations were made with infective sap of cloves and top-sets. 7. Physical properties of the garlic mosaic virus as determined by inoculation onto C. amaranticolor were as follows. Thermal inactivation point: $65-70^{\circ}C$, Dilution end poiut: $10^-2-10^-3$, Aging in vitro: 2 days. 8. Electron microscopic examination of the garlic mosaic virus revealed long rod shaped particles measuring 1200-1250mu. 9. Garlic mosaic virus was purified from leaf materials of C. amaranticolor by using two cycles of differential centrifugation followed by Sephadex gel filtration. 10. Garlic mosaic virus was successfully detected from infected garlic cloves and top-sets by a serological microprecipitin test. 11 Serological tests of 150 garlic cloves and 30 top-sets collected randomly from seperated plants throughout five different garlic growing regions in Korea revealed $100\%$ infection with garlic mosaic virus. Accordingly it is concluded that most of the garlic cloves and top-sets now being used for propagation in Korea are carriers of the garlic mosaic virus. 12. Serological studies revealed that the garlic mosaic virus is not related with potato viruses X, Y, S and M. 13. Because of the difficulty in securing mosaic virus-free garlic plants, direct inoculation with isolated virus to the garlic plants was not accomplished. Results of the present study, however, indicate that the virus isolate used here is the causal virus of the garlic mosaic disease in Korea.

• Korean Journal of Veterinary Research
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• v.64 no.2
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• pp.13.1-13.6
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• 2024

Avian influenza A viruses (IAVs) present significant threats to both animal and human health through their potential for cross-species transmission and global spread. Clade 2.3.4.4 H5Nx highly pathogenic avian IAVs initially emerged in East Asia between 2013 and 2014. Since then, they have spread to Europe, Africa, and America via migratory bird flyways. However, beyond viral transmission primarily facilitated by migratory birds, the potential involvement of other intermediate factors for virus transmission remains poorly investigated. This study aimed to investigate the role of wild rodents as intermediary hosts in the ecology of avian IAVs in Gyeonggi province, South Korea. By capturing and analyzing 189 wild rodents near poultry farms and migratory bird habitats in 2013 and 2014 and employing serological assays and virus isolation techniques, we found no evidence of IAV infection among these populations. Our results suggest that wild rodents may not significantly contribute to the transmission dynamics of IAVs within these regions.

• BMB Reports
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• v.39 no.1
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• pp.9-15
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• 2006

To prove whether error catastrophe /lethal mutagenesis is the primary antiviral mechanism of action of ribavirin against foot-and-mouth disease virus (FMDV). Ribavirin passage experiments were performed and supernatants of $Rp_1$ to $Rp_5$ were harvested. Morphological alterations as well as the levels of viral RNAs, proteins, and infectious particles in the BHK-21 cells infected using the supernatants of $Rp_1$ to $Rp_5$ and control were measured by microscope, real-time RT-PCR, western-blotting and plaque assays, respectively. The mutation frequency was measured by sequencing the complete P1- and 3D-encoding region of FMDV after a single round of virus infection from ribavirin-treated or untreated FMDV-infected cells. Ribavirin treatment for FMDV caused dramatically inhibition of multiplication in cell cultures. The levels of viral RNAs, proteins, and infectious particles in the BHK-21 cells infected were more greatly reduced along with the passage from $Rp_1$ to $Rp_5$, moreover, nucleocapsid protein could not be detected and no recovery of infectious virus in the supernatant or detection of intracellular viral RNA was observed at the $Rp_5$-infected cells. A high mutation rate, giving rise to an 8-and 11-fold increase in mutagenesis and resulting in some amino acid substitutions, was found in viral RNA synthesized at a single round of virus infection in the presence of ribavirin of $1000\;{\mu}M$ and caused a 99.7% loss in viral infectivity in contrast with parallel untreated control virus. These results suggest that the antiviral molecular mechanism of ribavirin is based on the lethal mutagenesis/error catastrophe, that is, the ribavirin is not merely an antiviral reagent but also an effective mutagen.

• Journal of Sericultural and Entomological Science
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• v.25 no.2
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• pp.37-43
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• 1984

The prevalence of the infectious flacherie virus (FV) disease causes a severe damage to cocoon yield and various methods to control the disease have been studied. In this regard, guanidine hydrochloride (GH), one of the guanidine derivatives known as the most inhibitory agent against the replication of picorna virus, was applied to silkworms per os with mulberry leaves and the results were as follows. 1. The application of GH below 0.01% of the chemical concentration did not give any damage to silkworm larvae. 2. The transmission of the virus disease by introducing the FV infected larvae to the healthy larvae group was proportioned to the number of infected larvae. When l% of infected larvae was introduced to the rearing tray of healthy larvae, the pupation rate was 70.7%(79) and it was 38.4% (43) to 5% of infected larvae introduced, while the control of non-mixed with infected larvae gave 89.2% (100) of pupation rate. The cocoon yield from 10,000 larvae also showed the same tendency as the pupation rate. 3. The inhibitory effect of GH against the replication of FV showed ten times in treatment of 0,01% of the chemical agent compared to the non-treatment. 4. The successive application of GH after virus inoculation to silkworm larvae led to the most effective on the inhibition of the virus replication. 5. The immediate application of GH after the virus inoculation also gave the best effect on the inhibition of the virus replication in silkworm larvae. 6. The effect of GH on the inactivation of FV in vitro was not observed.

• Journal of applied mathematics & informatics
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• v.41 no.1
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• pp.107-121
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• 2023

An epidemic infectious disease model consists of six compartments viz. Susceptible, Exposed, Infected, Quarantine, Recovered, and Virus with nonlinear saturation incidence rate is proposed to know the viral disease dynamics. There exist two biological equilibrium points for the model system. The system's local and global stability is done through Lyapunov's direct method about equilibrium points. The sensitivity analysis has been performed for the basic reproduction number and equilibrium points through the normalized forward sensitivity index. Sensitivity analysis shows that virus growth and quarantine rates are more sensitive parameters. In support of mathematical conclusions, numerical experimentation has been shown.

• Genomics & Informatics
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• v.9 no.3
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• pp.127-133
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• 2011

The Epstein-Barr virus-transformed lymphoblastoid cell line (LCL) is one of the major genomic resources for human genetics and immunological studies. Use of LCLs is currently extended to pharmacogenetic studies to investigate variations in human gene expression as well as drug responses between individuals. We evaluated four common internal controls for gene expression analysis of selected hematopoietic transcriptional regulatory genes between B cells and LCLs. In this study, the expression pattern analyses showed that TBP (TATA box-binding protein) is a suitable internal control for normalization, whereas GAPDH (glyceraldehyde-3-phosphate dehydrogenase) is not a good internal control for gene expression analyses of hematopoiesis-related genes between B cells and LCLs at different subculture passages. Using the TBP normalizer, we found significant gene expression changes in selected hematopoietic transcriptional regulatory genes (downregulation of RUNX1, RUNX3, CBFB, TLE1, and NOTCH2 ; upregulation of MSC and PLAGL2) between B cells and LCLs at different passage numbers. These results suggest that these hematopoietic transcriptional regulatory genes are potential cellular targets of EBV infection, contributing to EBV-mediated B-cell transformation and LCL immortalization.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.6
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• pp.679-684
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• 1996

This study evaluates the susceptibility of scaleless mutant chickens to very virulent Marek's disease virus (vvMDV) inoculation. One day old chickens were inoculated subcutaneously with Taiwanese isolates of LTB-1 and LTS-1 strains, and standard strain of Md/5. Compared with the non-inoculated group the vvMDV-inoculated chickens showed decreased body weights and atrophy of lymphoid organs before 35 days old. These results indicate that scaleless chickens show the same susceptibility as the wild type chickens to vvMDV infection. Furthermore, the protective effect of herpesvirus of turkey (HVT) vaccination at 1 day old against vvMDV challenge was evaluated. Scaleless mutant chickens of treated groups showed 20-30% early death, and 85.7-100% and 12.5-14.2% had lymphomatous lesions in visceral organs and peripheral nerves, respectively. No significant lesions were observed in non-challenged chickens of the control group. The HVT vaccination did not provide an effective protection against vvMDV infection. It is concluded that scaleless mutant chickens are susceptible to vvMDV infection.

• Journal of Preventive Medicine and Public Health
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• v.38 no.2
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• pp.117-124
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• 2005

Before twentieth centuries and during early twentieth centuries, communicable diseases were the major cause of morbidity and mortality in Korea. But reliable data are not available. After 1975, the overall morbidity and mortality from communicable diseases, rapidly declined. Recently many new pathogenic microbes were recognized: L. monocytogenes, Hantaan virus, Y. pseudotuberculosis, P. multocida, L. pneumophilia, Human immunodeficiency virus (HIV), G. seoi, H. capsulatum, C. burnetii, V. cholerae O139, C. parvum, F. tularensis, E. coli O157:H7, B. burgdorferi, S. Typhimurium DT104, Rotavirus, hepatitis C virus and so on. Since the first HIV infection recognized in 1985, the reported cases of infection and deaths from HIV/AIDS have been steady increased each year. Legionnaire's disease, E. coli O157:H7 colitis, listeriosis and crytosporidiasis have been occurring just sporadically among immunocompromized cases. Many re-emerging communicable diseases were occurred in Korea: leptospirosis, malaria, endemic typhus, cholera, tsutsugamushi disease, salmonellosis, hepatitis A, shigellosis, mumps, measles, acute hemorrhagic conjunctivitis, brucellosis and so on. Leptospirosis and tsutsugamushi diseases have been noticed as major public health problems since 1980s. The malaria that had been virtually disappeared for a decade has reappeared from 1993 with striking increase of patients in recent 3-4 years. The distributions of salmonella and shigella serotypes have been changed a lot in recent few decades. Furthermore rapid emergence of antibiotic-resistant bacterial strains induces more difficult and complex problems in control of communicable diseases. We must recognize on the importance of environment and ecosystem conservation and careful prescription of anti-microbial agent in order to prevent communicable diseases.

• Clinical and Experimental Pediatrics
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• v.55 no.12
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• pp.470-473
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• 2012

Purpose: The purpose of this prospective case-control study was to survey the detection rate of respiratory viruses in children with Kawasaki disease (KD) by using multiplex reverse transcriptase-polymerase chain reaction (RT-PCR), and to investigate the clinical implications of the prevalence of respiratory viruses during the acute phase of KD. Methods: RT-PCR assays were carried out to screen for the presence of respiratory syncytial virus A and B, adenovirus, rhinovirus, parainfluenza viruses 1 to 4, influenza virus A and B, metapneumovirus, bocavirus, coronavirus OC43/229E and NL63, and enterovirus in nasopharyngeal secretions of 55 KD patients and 78 control subjects. Results: Virus detection rates in KD patients and control subjects were 32.7% and 30.8%, respectively (P=0.811). However, there was no significant association between the presence of any of the 15 viruses and the incidence of KD. Comparisons between the 18 patients with positive RT-PCR results and the other 37 KD patients revealed no significant differences in terms of clinical findings (including the prevalence of incomplete presentation of the disease) and coronary artery diameter. Conclusion: A positive RT-PCR for currently epidemic respiratory viruses should not be used as an evidence against the diagnosis of KD. These viruses were not associated with the incomplete presentation of KD and coronary artery dilatation.

• Korean Journal of Poultry Science
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• v.34 no.1
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• pp.57-76
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• 2007

Marek's disease (MD) is caused by a ubiquitous, lymphotropic alphaherpesvirus, MD virus (MDV). MD has been a major concern in the poultry industry due to the emergence of increasingly virulent strains over the last few decades that were isolated in the face of comprehensive vaccination. MD is characterized by a variety of clinical signs, amongst them neurological symptoms, chronic wasting, and most notably the development of multiple lymphomas that manifest as solid tumors in the viscera and musculature. Much work has been devoted to study MD-induced oncogenesis and genes involved in this process. Among the many genes encoded by MDV, a number have recently been shown to affect the development of tumors in chickens, one protein directly causing transformation of cells (Meq) and another being involved in maintaining transformed cells (vTR). Other MDV gene products modulate and are involved in early lytic in vivo replication, thereby increasing the chance of transformation occurring. In this review, specific genes encoded by MDV that are involved in the initiation and/or maintenance of transformation were briefly summarized, and limits of current vaccination and new control strategies against MD, particularly how modem molecular biological methods may be used to improve strategies to combat the disease in the future, were discussed.