• Korean Journal of Agricultural Science
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• v.49 no.1
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• pp.121-128
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• 2022

Fusarium wilt disease caused by Fusarium species is a major problem affecting cultivated cucurbit plants worldwide. Fusarium species are well-known soil-borne pathogenic fungi that cause Fusarium wilt disease in several cucurbit plants. In this study, we aimed to identify and classify pathogenic Fusarium species from cultivated Korean cucurbit plants, specifically watermelon and cucumber. Thirty-six Fusarium isolates from different regions of Korea were obtained from the National Institute of Horticulture and Herbal Science Germplasm collection. Each isolate was morphologically and molecularly identified using an internal transcribed spacer of ribosomal DNA, elongation factor-1α, and the beta-tubulin gene marker sequence. Fusarium species that infect the cucurbit plant family could be divided into three groups: Fusarium oxysporum (F. oxysporum), Fusarium solani (F. solani), and Fusarium equiseti (F. equieti). Among the 36 isolates examined, six were non-pathogenic (F. equiseti: 15-127, F. oxysporum: 14-129, 17-557, 17-559, 18-369, F. solani: 12-155), whereas 30 isolates were pathogenic. Five of the F. solani isolates (11-117, 14-130, 17-554, 17-555, 17-556) were found to be highly pathogenic to both watermelon and cucumber plants, posing a great threat to cucurbit production in Korea. The identification of several isolates of F. equiseti and F. oxysporum, which are both highly pathogenic to bottle gourd, may indicate waning resistance to Fusarium species infection.

• Korean Journal of Exercise Nutrition
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• v.23 no.3
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• pp.13-21
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• 2019

[Purpose] Chronic stress is a precipitating factor for depression, whereas exercise is beneficial for both the mood and cognitive process. The current study demonstrates the anti-depressive effects of regular exercise and the mechanisms linked to hippocampal neurogenesis. [Methods] Mice were subjected to 14 consecutive days of restraint, followed by 3 weeks of treadmill running, and were then subjected to behavioral tests that included the forced swimming and Y-maze tests. Protein levels were assessed using western blot analysis and newborn cells were detected using 5-bromo-2'-deoxyuridine (BrdU). [Results] Three weeks of treadmill running ameliorated the behavioral depression caused by 14 days of continuous restraint stress. The exercise regimen enhanced BrdU-labeled cells and class III β-tubulin levels in the hippocampal dentate gyrus, as well as those of thioredoxin-1 (TRX-1) and synaptosomal β2-adrenergic receptors (β2-AR) under stress. In vitro experiments involving treatment with recombinant human TRX-1 (rhTRX-1) augmented the levels of phospho-extracellular signal-regulated kinases 1 and 2 (ERK1/2), nuclear β-catenin, and proliferating cell nuclear antigens, which were previously inhibited by U0216 and FH535 (inhibitors of ERK1/2 and β-catenin/T cell factor-mediated transcription, respectively). The hippocampal neurogenesis elicited by a 7-day exercise regimen was abolished by a selective inhibitor of β2-AR, butoxamine. [Conclusion] These results suggest that TRX-1-mediated hippocampal neurogenesis by β2-AR function is a potential mechanism underlying the psychotropic effect of exercise.

• Mycobiology
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• v.51 no.6
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• pp.401-409
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• 2023

Nigrospora (Xylariales, Apiosporaceae) consists of species of terrestrial plant endophytes and pathogens. Nigrospora has also been reported in marine environments such as mangroves, sea fans, and macroalgae. However, limited research has been conducted on Nigrospora associated with macroalgae. Here, we isolated Nigrospora species from three types of algae (brown, green, and red algae) from Korean islands (Chuja, Jeju, and Ulleung) based on phylogenetic analyses of multigenetic markers: the internal transcribed spacers (ITS), beta-tubulin (BenA), and translation elongation factor 1 (TEF1-α). A total of 17 Nigrospora strains were isolated from macroalgae and identified as nine distinct species. The majority of Nigrospora species (seven) were found on brown algae, followed by red algae (three), and then green algae (two). To our understanding, this study represents the first account of N. cooperae, N. covidalis, N. guilinensis, N. lacticolonia, N. osmanthi, N. pyriformis, and N. rubi occurring in marine environments. Additionally, this study provides the first report of the occurrence of N. cooperae, N. covidalis, N. guilinensis, N. lacticolonia, and N. osmanthi in South Korea. This study will provide valuable insights for future research exploring the functions of fungi in macroalgal communities.

• Journal of Biomedical Engineering Research
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• v.44 no.6
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• pp.443-449
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• 2023

The purpose of this study was to observe cell death in human keratinocytes stimulated against the infectious cytokines TNF-α and IFN-γ, and to observe the expression of Phospho-NF-κB due to phosphorylation of IkB to confirm the mechanism of inhibiting the expression of inflammatory cytokines. As a result of cell viability analysis, differences in PEMF stimulation time were observed little by little after 1 hour, 3 hours, 6 hours, 12 hours, 24 hours, and 48 hours, but there was no statistical significance according to PEMF stimulation time for each time (p>0.05). No significant difference was observed in the total amount of NF-κB present in the cytoplasm and nucleus, but a significant decrease in the expression of phosphorylated NF-κB was observed in the group exposed to PEMF stimulation for 24 hours (^*p<0.05). The expression of IL-1β was observed in all inflammation-induced groups, and the concentration of IL-1β compared to α-Tubulin expression was reduced by about 54% in the PEMF-stimulated group for 24 hours compared to the control group (^***p<0.001). As a result of the study, it is shown that PEMF stimulation does not negatively affect HaCaT cells from 0 to 48 hours and can inhibit the expression of inflammatory cytokines by inhibiting the pathway of NF-κB.

• The Korean Journal of Mycology
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• v.51 no.3
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• pp.179-190
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• 2023

Grapevine downy mildew, caused by Plasmopara viticola, significantly damages vineyards and is one of the most devastating diseases affecting cultivated grapes worldwide. In this study, we characterized the phenotypic and molecular traits of 11 P. viticola isolates from four grape-growing regions in South Korea. Additionally, we investigated the diversity of pathogenicity among these isolates and conducted an assay to evaluate the response of grape cultivars to P. viticola infection. Lemon-shaped sporangia were identified in the collected isolates, which released zoospores into the suspension at room temperature. Within a few hours of inoculation, the zoospores developed germ tubes. We tested 11 P. viticola isolates for pathogenicity in 845 grape cultivars to screen for grape host resistance to downy mildew infection. Among the tested isolates, JN-9 showed the highest virulence. Grape cultivars displayed varying phenotypic reactions to P. viticola infection: approximately 7% were highly susceptible, 41% were susceptible, 20% were moderately susceptible, 8% were resistant, and 24% exhibited extreme resistance. Phylogenetic analysis based on four genomic regions (internal transcribed spacer 1 [ITS1], actin, beta-tubulin, and cytochrome c oxidase II) revealed a close evolutionary relationship among all the Korean isolates, forming a single monophyletic lineage. Notably, these isolates showed greater similarity to European isolates than to American isolates. This comprehensive study contributes to a deeper understanding of the identity and behavior of P. viticola, which is crucial for developing effective resistance strategies against this pathogen in grape cultivars cultivated in South Korea.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.64-70
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• 2013

The greenhouse whitefly, Trialeurodes vaporariorum, is an economically important pest for greenhouse crops because they cause direct damage by feeding on plant nutrients and indirect damage as transmits many virus vectors. It has recently become a serious problem because of the continuous use of insecticide resulting in resistance among greenhouse whitefly population. To overcome these problems, in this study, the biological characteristics and virulence of an entomopathogenic fungus isolated from the cadaver of nymph greenhouse whitefly were investigated. Isolated fungus was identified as Isaria fumosorosea by morphological examinations and genetic identification using sequences of the ITS, ${\beta}$-tubulin, and EF1-${\alpha}$ regions. This fungus was named as I. fumosorosea SDTv and tested for the virulence against nymphs T. vaporariorum and the cold activity, the thermotolerance and the stability of UV-B irradiation on conidia. Mortality rate of greenhouse whitefly showed from 84 to 100% and the virulence increased with increasing conidial concentrations, $1{\times}10^5$ to $10^8$ conidia/ml. Conidia were stable at $35^{\circ}C$, 0.1 $J/cm^2$ of UV irradiation and germinated after 8 days at $4^{\circ}C$. Additionally, the activities of chitinases and proteases produced by I. fumosorosea SDTv were varied according to the medium. In conclusion, I. fumosorosea SDTv which showed high mortality rate against greenhouse whitefly will be used effectively in the integrated pest management programs against the greenhouse whitefly.

• The Korean Journal of Mycology
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• v.43 no.3
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• pp.200-205
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• 2015

Perilla frutescens var. japonica Hara was collected from farmland in Seongju-gun. Fifteen endophytic fungal strains with different colony morphologies were isolated from roots of P. frutescens. Waito-c rice seedlings were treated with the concentrated culture filtrates (CF) of endophytic fungi for observation of their plant growth-promoting activities. In the results, the CF of Y2H001 fungal strain promoted the growth of the waito-c rice seedlings. The phylogenetic tree of Y2H001 strain was analyzed by the combined sequences of the partial internal transcribed spacer region (ITS) and partial betatubulin gene. Molecular and morphological studies identified the Y2H001 strain as belonging to Aspergillus flavus. In gas chromatography mass spectrometry (GC/MS) analysis of the CF of Y2H001 strain, gibberellic acid (GA) was detected and quantified. Therefore, we describe Y2H001 strain as a new $GA_3$-producing A. flavus based on morphological, molecular characteristics and analysis of secondary metabolite.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.101-101
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• 2003

Main strategy for a treatment of Parkinson's disease (PD), due to a progressive degeneration of dopaminergic neurons, is a pharmaceutical supplement of dopamine derivatives or ceil replacement therapy. Both of these protocols have pros and cons; former exhibiting a dramatic relief but causing a severe side effects on long-term prescription and latter also having a proven effectiveness but having availability and ethical problems Embryonic stem (ES) cells have several characteristics suitable for this purpose. To investigate a possibility of using ES cells as a carrier of therapeutic gene(s), human ES (hES, MB03) cells were transfected with cDNAs coding for tyrosine hydroxylase (TH) in pcDNA3.1 (+) and the transfectants were selected using neomycin (250 $\mu /ml$). Expression of TH being confirmed, two of the positive clone (MBTH2 & 8) were second transfected with GTP cyclohydrolase 1 (GTPCH 1) in pcDNA3.1 (+)-hyg followed by selection with hygromycin-B (150 $\mu /ml$) and RT-PCR confirmation. By immune-cytochemistry, these genetically modified but undifferentiated dual drug-resistant cells were found to express few of the neuronal markers, such as NF200, $\beta$-tubulin, and MAP2 as well as astroglial marker GFAP. This results suggest that over-production of BH4 by ectopically expressed GTPCH I may be involved in the induction of those markers. Transplantation of the cells into striatum of 6-OHDA- denervated PD animal model relieved symptomatic rotational behaviors of the animals. Immunohistochemical analyses showed the presence of human cells within the striatum of the recipients. These results suggest a possibility of using hES cells as a carrier of therapeutic gene(s).

• Parasites, Hosts and Diseases
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• v.55 no.2
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• pp.207-212
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• 2017

Infections of Toxoplasma gondii and Babesia microti are reported in many wild animals worldwide, but information on their incidence and molecular detection in Korean wild fields is limited. In this study, the prevalence of T. gondii and B. microti infection in blood samples of 5 animal species (37 Chinese water deer, 23 raccoon dogs, 6 roe deer, 1 wild boar, and 3 Eurasian badgers) was examined during 2008-2009 in Gangwon-do (Province), the Republic of Korea (=Korea) by using serological and molecular tests. The overall seropositivity of T. gondii was 8.6% (6/70); 10.8% in Chinese water deer, 4.3% in raccoon dogs, and 16.7% in roe deer. PCR revealed only 1 case of T. gondii infection in Chinese water deer, and phylogenic analysis showed that the positive isolate was practically identical to the highly pathogenetic strain type I. In B. microti PCR, the positive rate was 5.7% (4/70), including 2 Chinese water deer and 2 Eurasian badgers. Phylogenetic analysis results of 18S rRNA and the ${\beta}$-tubulin gene showed that all positive isolates were US-type B. microti. To our knowledge, this is the first report of B. microti detected in Chinese water deer and Eurasian badger from Korea. These results indicate a potentially high prevalence of T. gondii and B. microti in wild animals of Gangwon-do, Korea. Furthermore, Chinese water deer might act as a reservoir for parasite infections of domestic animals.

• ALGAE
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• v.33 no.1
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• pp.1-19
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• 2018

Members of the family Parviluciferaceae (Alveolata, Perkinsozoa) are the well-known dinoflagellate parasitoids along with Amoebophrya ceratii species complex and parasitic chytrid Dinomyces arenysensis and contain six species across three genera (i.e., Parvilucifera infectans, P. sinerae, P. rostrata, and P. corolla, Dinovorax pyriformis, and Snorkelia prorocentri) so far. Among Parvilucifera species, the two species, P. infectans and P. sinerae, are very similar or almost identical each other morphologically and genetically, thereby make it difficult to distinguish between the two. The only main difference between the two species known so far is the number of sporangium wall (i.e., 2 layers in P. infectans vs. 3 layers in P. sinerae). During sampling in Masan bay, Korea during the spring season of 2015, the dinoflagellate Akashiwo sanguinea cells infected by the parasite Parvilucifera were observed and this host-parasite system was established in culture. Using this culture, its morphological and ultrastructural features with special emphasis on the variation in the number of sporangium wall over developmental times, were investigated. In addition, the sequences of rDNA regions and ${\beta}-tubulin$ genes were determined. The result clearly demonstrated that the trophocyte at 36 h was covered with 4 layers, and then outer layer of the sporocyte gradually degraded over time, resulting in wall structure consisting of two layers, with even processes being detached from 7-day-old sporangium with smooth surface, indicating that the difference in the number of layers seems not to be an appropriate ultrastructural character for distinguishing P. infectans and P. sinerae. While pairwise comparison of the large subunit rDNA sequences showed 100% identity among P. infectans / P. sinerae species complex, genetic differences were found in the small subunit (SSU) rDNA sequences but the differences were relatively small (11-13 nucleotides) compared with those (190-272 nucleotides) found among the rest of Parvilucifera species (P. rostrata and P. corolla). Those small differences in SSU rDNA sequences of P. infectans / P. sinerae species complex may reflect the variations within inter- strains of the same species from different geographical areas. Taken together, all morphological, ultrastructural, and molecular data from the present study suggest that they are the same species.