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Search Results: 1 - 10 of 5249 matches for " Won Kyong Cho "
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A Current Overview of Two Viroids That Infect Chrysanthemums: Chrysanthemum stunt viroid and Chrysanthemum chlorotic mottle viroid
Won Kyong Cho,Yeonhwa Jo,Kyoung-Min Jo,Kook-Hyung Kim
Viruses , 2013, DOI: 10.3390/v5041099
Abstract: The chrysanthemum ( Dendranthema X grandiflorum) belongs to the family Asteraceae and it is one of the most popular flowers in the world. Viroids are the smallest known plant pathogens. They consist of a circular, single-stranded RNA, which does not encode a protein. Chrysanthemums are a common host for two different viroids, the Chrysanthemum stunt viroid (CSVd) and the Chrysanthemum chlorotic mottle viroid (CChMVd). These viroids are quite different from each other in structure and function. Here, we reviewed research associated with CSVd and CChMVd that covered disease symptoms, identification, host range, nucleotide sequences, phylogenetic relationships, structures, replication mechanisms, symptom determinants, detection methods, viroid elimination, and development of viroid resistant chrysanthemums, among other studies. We propose that the chrysanthemum and these two viroids represent convenient genetic resources for host–viroid interaction studies.
Evolution of and Horizontal Gene Transfer in the Endornavirus Genus
Dami Song, Won Kyong Cho, Sang-Ho Park, Yeonhwa Jo, Kook-Hyung Kim
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0064270
Abstract: The transfer of genetic information between unrelated species is referred to as horizontal gene transfer. Previous studies have demonstrated that both retroviral and non-retroviral sequences have been integrated into eukaryotic genomes. Recently, we identified many non-retroviral sequences in plant genomes. In this study, we investigated the evolutionary origin and gene transfer of domains present in endornaviruses which are double-stranded RNA viruses. Using the available sequences for endornaviruses, we found that Bell pepper endornavirus-like sequences homologous to the glycosyltransferase 28 domain are present in plants, fungi, and bacteria. The phylogenetic analysis revealed the glycosyltransferase 28 domain of Bell pepper endornavirus may have originated from bacteria. In addition, two domains of Oryza sativa endornavirus, a glycosyltransferase sugar-binding domain and a capsular polysaccharide synthesis protein, also exhibited high similarity to those of bacteria. We found evidence that at least four independent horizontal gene transfer events for the glycosyltransferase 28 domain have occurred among plants, fungi, and bacteria. The glycosyltransferase sugar-binding domains of two proteobacteria may have been horizontally transferred to the genome of Thalassiosira pseudonana. Our study is the first to show that three glycome-related viral genes in the genus Endornavirus have been acquired from marine bacteria by horizontal gene transfer.
Genome-wide expression profiling shows transcriptional reprogramming in Fusarium graminearum by Fusarium graminearum virus 1-DK21 infection
Won Kyong Cho, Jisuk Yu, Kyung-Mi Lee, Moonil Son, Kyunghun Min, Yin-Won Lee, Kook-Hyung Kim
BMC Genomics , 2012, DOI: 10.1186/1471-2164-13-173
Abstract: Using a 3′-tiling microarray covering all known F. graminearum genes, we carried out genome-wide expression analyses of F. graminearum at two different time points. At the early point of growth of an infected strain as compared to an uninfected strain, genes associated with protein synthesis, including ribosome assembly, nucleolus, and ribosomal RNA processing, were significantly up-regulated. In addition, genes required for transcription and signal transduction, including fungal-specific transcription factors and cAMP signaling, respectively, were actively up-regulated. In contrast, genes involved in various metabolic pathways, particularly in producing carboxylic acids, aromatic amino acids, nitrogen compounds, and polyamines, showed dramatic down-regulation at the early time point. Moreover, genes associated with transport systems localizing to transmembranes were down-regulated at both time points.This is the first report of global change in the prominent cellular pathways in the Fusarium host containing FgV1-DK21. The significant increase in transcripts for transcription and translation machinery in fungal host cells seems to be related to virus replication. In addition, significant down-regulation of genes required for metabolism and transporting systems in a fungal host containing the virus appears to be related to the host defense mechanism and fungal virulence. Taken together, our data aid in the understanding of how FgV1-DK21 regulates the transcriptional reprogramming of F. graminearum.
A Comparison of Transcriptional Patterns and Mycological Phenotypes following Infection of Fusarium graminearum by Four Mycoviruses
Kyung-Mi Lee, Won Kyong Cho, Jisuk Yu, Moonil Son, Hoseong Choi, Kyunghun Min, Yin-Won Lee, Kook-Hyung Kim
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0100989
Abstract: Many fungi-infecting viruses, which are termed mycoviruses, have been identified, and most do not cause any visible symptoms. Some mycoviruses, however, can attenuate the virulence of the infected fungi, a phenomenon referred to as hypovirulence. To study fungus responses to virus infection, we established a model system composed of Fusarium graminearum and four mycoviruses including FgV1 (Fusarium graminearum virus 1), FgV2, FgV3, and FgV4. FgV1 and FgV2 infections caused several phenotypic alterations in F. graminearum including abnormal colony morphology, defects in perithecium development, and reductions in growth rate, conidiation, and virulence. In contrast, FgV3 and FgV4 infections did not cause any phenotypic change. An RNA-Seq-based analysis of the host transcriptome identified four unique Fusarium transcriptomes, one for each of the four mycoviruses. Unexpectedly, the fungal host transcriptome was more affected by FgV1 and FgV4 infections than by FgV2 and FgV3 infections. Gene ontology (GO) enrichment analysis revealed that FgV1 and FgV3 infections resulted in down-regulation of host genes required for cellular transport systems. FgV4 infection reduced the expression of genes involved in RNA processing and ribosome assembly. We also found 12 genes that were differentially expressed in response to all four mycovirus infections. Unfortunately, functions of most of these genes are still unknown. Taken together, our analysis provides further detailed insights into the interactions between mycoviruses and F. graminearum.
Phylogenetic and Recombination Analysis of Tomato Spotted Wilt Virus
Sen Lian, Jong-Seung Lee, Won Kyong Cho, Jisuk Yu, Mi-Kyeong Kim, Hong-Soo Choi, Kook-Hyung Kim
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0063380
Abstract: Tomato spotted wilt virus (TSWV) severely damages and reduces the yield of many economically important plants worldwide. In this study, we determined the whole-genome sequences of 10 TSWV isolates recently identified from various regions and hosts in Korea. Phylogenetic analysis of these 10 isolates as well as the three previously sequenced isolates indicated that the 13 Korean TSWV isolates could be divided into two groups reflecting either two different origins or divergences of Korean TSWV isolates. In addition, the complete nucleotide sequences for the 13 Korean TSWV isolates along with previously sequenced TSWV RNA segments from Korea and other countries were subjected to phylogenetic and recombination analysis. The phylogenetic analysis indicated that both the RNA L and RNA M segments of most Korean isolates might have originated in Western Europe and North America but that the RNA S segments for all Korean isolates might have originated in China and Japan. Recombination analysis identified a total of 12 recombination events among all isolates and segments and five recombination events among the 13 Korea isolates; among the five recombinants from Korea, three contained the whole RNA L segment, suggesting reassortment rather than recombination. Our analyses provide evidence that both recombination and reassortment have contributed to the molecular diversity of TSWV.
EGb761, a Ginkgo Biloba Extract, Is Effective Against Atherosclerosis In Vitro, and in a Rat Model of Type 2 Diabetes
Soo Lim, Ji Won Yoon, Seon Mee Kang, Sung Hee Choi, Bong Jun Cho, Min Kim, Ho Seon Park, Hyun Ju Cho, Hayley Shin, Young-Bum Kim, Hyo Soo Kim, Hak Chul Jang, Kyong Soo Park
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0020301
Abstract: Background EGb761, a standardized Ginkgo biloba extract, has antioxidant and antiplatelet aggregation and thus might protect against atherosclerosis. However, molecular and functional properties of EGb761 and its major subcomponents have not been well characterized. We investigated the effect of EGb761 and its major subcomponents (bilobalide, kaemferol, and quercetin) on preventing atherosclerosis in vitro, and in a rat model of type 2 diabetes. Methods and Results EGb761 (100 and 200 mg/kg) or normal saline (control) were administered to Otsuka Long-Evans Tokushima Fatty rats, an obese insulin-resistant rat model, for 6 weeks (from 3 weeks before to 3 weeks after carotid artery injury). Immunohistochemical staining was performed to investigate cell proliferation and apoptosis in the injured arteries. Cell migration, caspase-3 activity and DNA fragmentation, monocyte adhesion, and ICAM-1/VCAM-1 levels were explored in vitro. Treatment with EGb761 dose-dependently reduced intima-media ratio, proliferation of vascular smooth muscle cells (VSMCs) and induced greater apoptosis than the controls. Proliferation and migration of VSMCs in vitro were also decreased by the treatment of EGb761. Glucose homeostasis and circulating adiponectin levels were improved, and plasma hsCRP concentrations were decreased in the treatment groups. Caspase-3 activity and DNA fragmentation increased while monocyte adhesion and ICAM-1/VCAM-1 levels decreased significantly. Among subcomponents of EGb761, kaemferol and quercetin reduced VSMC migration and increased caspase activity. Conclusions EGb761 has a protective role in the development of atherosclerosis and is a potential therapeutic agent for preventing atherosclerosis.
Effect of a Dipeptidyl Peptidase-IV Inhibitor, Des-Fluoro-Sitagliptin, on Neointimal Formation after Balloon Injury in Rats
Soo Lim, Sung Hee Choi, Hayley Shin, Bong Jun Cho, Ho Seon Park, Byung Yong Ahn, Seon Mee Kang, Ji Won Yoon, Hak Chul Jang, Young-Bum Kim, Kyong Soo Park
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0035007
Abstract: Background Recently, it has been suggested that enhancement of incretin effect improves cardiac function. We investigated the effect of a DPP-IV inhibitor, des-fluoro-sitagliptin, in reducing occurrence of restenosis in carotid artery in response to balloon injury and the related mechanisms. Methods and Findings Otsuka Long-Evans Tokushima Fatty rats were grouped into four: control (normal saline) and sitagliptin 100, 250 and 500 mg/kg per day (n = 10 per group). Sitagliptin or normal saline were given orally from 1 week before to 2 weeks after carotid injury. After 3 weeks of treatment, sitagliptin treatment caused a significant and dose-dependent reduction in intima-media ratio (IMR) in obese diabetic rats. This effect was accompanied by improved glucose homeostasis, decreased circulating levels of high-sensitivity C-reactive protein (hsCRP) and increased adiponectin level. Moreover, decreased IMR was correlated significantly with reduced hsCRP, tumor necrosis factor-α and monocyte chemoattractant protein-1 levels and plasminogen activator inhibitor-1 activity. In vitro evidence with vascular smooth muscle cells (VSMCs) demonstrated that proliferation and migration were decreased significantly after sitagliptin treatment. In addition, sitagliptin increased caspase-3 activity and decreased monocyte adhesion and NFκB activation in VSMCs. Conclusions Sitagliptin has protective properties against restenosis after carotid injury and therapeutic implications for treating macrovascular complications of diabetes.
Two symmetry breaking mechanisms for the development of orientation selectivity in a neural system
Myoung Won Cho
Quantitative Biology , 2015,
Abstract: Orientation selectivity is a remarkable feature of the neurons located in the primary visual cortex. Provided that the visual neurons acquire orientation selectivity through activity-dependent Hebbian learning, the development process could be understood as a kind of symmetry breaking phenomenon in the view of physics. The key mechanisms of the development process are examined here in a neural system. Found is that there are at least two different mechanisms which lead to the development of orientation selectivity through breaking the radial symmetry in receptive fields. The first, a simultaneous symmetry breaking mechanism, bases on the competition between neighboring neurons, and the second, a spontaneous one, bases on the nonlinearity in interactions. It turns out that only the second mechanism leads to the formation of a columnar pattern which characteristics accord with those observed in an animal experiment.
The Application of the Korean Dietary Pattern Score; KNHANES (Korean National Health and Nutrition Examination Survey) 2007  [PDF]
Kyung Won Lee, Ji Eun Oh, Mi Sook Cho
Food and Nutrition Sciences (FNS) , 2012, DOI: 10.4236/fns.2012.312221
Abstract: The aim of this study was to apply the Korean Dietary Pattern Score (KDPS) to Korean subjects based on traditional Korean-style meals. The KDPS is based on the 3-Chup Bansang (the traditional Korean daily table setting) and considers the intake of 6 major food groups according to the Korean Dietary Reference Intakes (KDRIs). The KDPS consists of 2 parts: the Korean-Style Meal Score (KSMS) and the Food Group Score (FGS). The KDPS was applied dietary data collected during the Korean National Health and Nutrition Examination Survey (KNHANES) in 2007. Socio-demographic status, gender, age, and body mass index are all factors that have been shown to be meaningful predictors for the KDPS. When the effect of the KDPS on risk of disease was evaluated, a higher total KDPS was associated with a decreased risk of elevated systolic blood pressure (p < 0.05) and hypercholesterolemia (p < 0.05). In addition, as the KSMS increased, the risk of central obesity (p < 0.05) and hypertension (p < 0.01) significantly decreased. A higher total KDPS suggests a greater diversity of food intake, and therefore greater dietary diversity appears to lower the risk of disease. The KDPS is relevant because it integrates scores for Korean-style meal patterns and meal evaluation from a nutritional perspective. In conclusion, the KDPS is appropriate for evaluating the quality of diet, adherence to Korean-style meal patterns, and risk of related diseases. These results will be useful for evaluating the nation’s dietary patterns, nutrition, and health status when planning nutrition policies and programs.
Development Strategy of Infrastructure Risk Assessment Based Disaster Response and Management System  [PDF]
Eun-Ho Oh, Kyoon-Tai Kim, Kyong-Hoon Kim, Jin-Man Kim, Jin-Woo Cho
World Journal of Engineering and Technology (WJET) , 2014, DOI: 10.4236/wjet.2014.23B005
Abstract:

Major infrastructures such as levee, dam, bridge, road, etc. have a significant meaning in that they are the means to support ordinary social and industrial activities and also protect human and physical assets at the occurrence of disaster. Especially, integrated risk management of SOC facilities provides the policy maker in charge of SOC facility safety and related disaster prevention with a reasonable means of decision making and ultimately contributes to improving the safety of the applicable SOC facility. Furthermore, a variety of issues raised in the Sewol ferry disaster that occurred recently in Korea, such as, a proper response method and the relevant Golden time decision making at the occurrence of disaster, rapid grasping and reporting the situation on disaster sites, management and mobilization of resources for rescue and recover, loss of integrated control tower function, etc., might occur as well in facility disaster management. As the method of solving such issues adequately, this study suggests a strategy of new disaster response and management system. The analyses of Hazus-MH (FEMA) and DIMSuS (Purdue University) were comprehensively conducted, and based on the results required functions of new disaster response system of major infrastructure and its development directions were suggested.

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