• 동의생리병리학회지
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• 제30권1호
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• pp.54-60
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• 2016

Amomum cadamomum Linne (ACL) has long been utilized against the inhibited qi movement related diseases such as dyspepsia, acute gastroenteritis, vomiting and diarrhea in Korean medicine. We speculated that ACL could improve the metabolic disorders such as obesity and type 2 diabetes through removing the phlegm-dampness and promoting the qi movement or stagnation. This study was designed to investigate effects and molecular mechanisms of ACL extract on the improvement of adipocyte dysfunction induced by TNF-α in 3T3-L1 adipocytes. Potential roles of ACL extract in the lipogenesis, inhibition of inflammatory cytokines and insulin resistance, were investigated in this study. Also, we examined the adipose genes and signaling molecules related to insulin resistance and glucose uptake to elucidate its mechanism. Our data demonstrated that TNF-α significantly incresed the release of lipid droplets and the production of MCP-1 and IL-6 from adipocytes. In gene expression, TNF-α reduced the expression of aP2, PPARγ, C/EBPα, GLUT4, and IRS-1 related to lipogenesis and insulin sesitivity, while TNF-α increased the expression of MCP-1 related to inflammation. In addition, TNF-α down-regulated the PPARγ and IRS-1 protein and up-regulated the IRS-1 Ser307 phosphorylation. These alterations induced by TNF-α were prevented by the treatment of ACL extract. Thus, our results indicate that ACL extract can be used to prevent from the TNF-α-induced adipocyte dysfunction through insulin and PPARγ pathways.

• Asian Pacific Journal of Cancer Prevention
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• 제14권8호
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• pp.4853-4858
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• 2013

Objectives: To investigate whether hypoxia has an effect on regulation of multidrug resistance (MDR) to chemotherapeutic drugs in laryngeal carcinoma cells and explore the role of hypoxia-inducible factor-$1{\alpha}$ (HIF-$1{\alpha}$). Methods: Laryngeal cancer cells were cultured under normoxic and hypoxic conditions. The sensitivity of the cells to multiple drugs and levels of apoptosis induced by paclitaxel were determined by MTT assay and annexin-V/propidium iodide staining analysis, respectively. HIF-$1{\alpha}$ expression was blocked by RNA interference. The expression of HIF-$1{\alpha}$ gene was detected by real-time quantitative RT-PCR and Western blotting. The value of fluorescence intensity of intracellular adriamycin accumulation and retention in cells was evaluated by flow cytometry. Results: The sensitivity to multiple chemotherapy agents and induction of apoptosis by paclitaxel could be reduced by hypoxia (P<0.05). A the same time, the adriamycin releasing index of cells was increased (P<0.05). However, resistance acquisition subject to hypoxia in vitro was suppressed by down-regulating HIF-$1{\alpha}$ expression. Conclusion: HIF-$1{\alpha}$ could be considered as a key regulator for mediating hypoxia-induced MDR in laryngeal cancer cells via inhibition of drug-induced apoptosis and decrease in intracellular drug accumulation.

• The Plant Pathology Journal
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• 제36권2호
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• pp.133-147
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• 2020

Hexanal, a C-6 aldehyde has been implicated to have antimicrobial properties. Hence, this study was conducted to determine the antifungal activities of hexanal vapor against major postharvest pathogens of banana viz., Colletotrichum gloeosporioides and Lasiodiplodia theobromae. The pathogens were cultured in vitro and exposed to hexanal vapor at 600, 800, 1,000 and 1,200 ppm. Mycelial growth of both fungal pathogens were inhibited completely at 800 ppm and the incidence of anthracnose and stem-end rot diseases reduced by 75.2% and 80.2%, respectively. The activities of peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase and glucanase had transiently increased in hexanal vapor treated banana by 5 to 7 days and declined thereafter. Postharvest treatment of banana with hexanal vapor resulted in phospholipase D inhibition and also resulted in cell wall thickening of the treated fruit, which impeded the penetration of the pathogenic spores. This was further confirmed by scanning electron micrographs. The defense-related protein intermediaries had increased in hexanal vapor treated banana fruit, which suggests induced resistance against C. gloeosporioides and L. theobromae, via., the phenylpropanoid pathway which plays a significant role in hindering the pathogen quiescence. Delayed ripening due to inhibition of phospholipase D enzyme, inhibition of mycelial growth and induced systemic resistance by defense enzymes collectively contributed to the postharvest disease reduction and extended shelf life of fruit.

• 미생물학회지
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• 제40권3호
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• pp.232-236
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• 2004

Streptomyces coelicolor A3(2)의 acetyl xylan esterase (AxeA)가 Escherichia coli의 과산화수소 저항성에 미치는 영향을 알아보고자 하였다. AxeA 발현은 isopropyl-$\beta$-thiogalactoside로 유도되었고 생산된 AxeA는 SDS-polyacrylamide gel electrophoresis방법으로 확인하였다. AxeA 발현에 따른 과산화수소 저항성의 변화를 E. coli의 생장곡선과 생존율을 통하여 조사하였다. AxeA가 발현되지 않으면 모든 처리 농도 (1 mM, 2.5mM, 5mM)에서 균의 사멸이 일어났다. AxeA가 발현되는 조건에서는 5mM을 제외한 과산화수소 1mM와 2.5mM에서 E. coli의 사멸이 저지되었다. 또한 1.5mM의 과산화수소에 대한생존율이 59%에서 74%로 높다졌다. 동시에 E. coli의 최고생장온도에서에 근접한 $45^{\circ}C$에서의 생존율도 증가되는 결과를 얻었다. 그러므로 AxeA 단백질은 산화적 스트레스와 온도스트레스에 대해 교차 저항성을 나타내는 역할을 한다고 결론지었다.

• 한국전기전자재료학회논문지
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• 제26권3호
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• pp.246-251
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• 2013

Screen printing is commonly used to form the front/back electrodes in silicon solar cell. But it has caused high resistance and low aspect ratio, resulting in decreased conversion efficiency in solar cell. Recently the plating method has been combined with screen-printed c-Si solar cell to reduce the resistance and improve the aspect ratio. In this paper, we investigated the effect of light induced silver plating with screen-printed c-Si solar cells and compared their electrical properties. All wafers were textured, doped, and coated with anti-reflection layer. The metallization process was carried out with screen-printing, followed by co-fired. Then we performed light induced Ag plating by changing the plating time in the range of 20 sec~5min with/without external light. For comparison, we measured the light I-V characteristics and electrode width by optical microscope. During plating, silver ions fill the porous structure established in rapid silver particle sintering during co-firing step, which results in resistance decrease and efficiency improvement. The plating rate was increased in presence of light lamp, resulting in widening the electrode with and reducing the short-circuit current by shadowing loss. With the optimized plating condition, the conversion efficiency of solar cells was increased by 0.4% due to decreased series resistance. Finally we obtained the short-circuit current of 8.66 A, open-circuit voltage of 0.632 V, fill factor of 78.2%, and efficiency of 17.8% on a silicon solar cell.

• 생명과학회지
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• 제19권8호
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• pp.1023-1032
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• 2009

TNF-related apoptosis-inducing ligand (TRAIL) 는 암세포에만 작용하고 정상세포에는 영향을 주지 않는 항암제로서 알려져 있지만, TRAIL에 내성을 나타내는 암세포의 출현이 문제점으로 지적되고 있다. 사람 백혈병세포인 K562 및 CEM 세포는 TRAIL에 내성을 나타낸다. 본 연구에서는 이러한 백혈병 세포의 TRAIL 내성에 대한 새로운 표적 분자의 발굴과 이를 토대로 한 새로운 내성극복 방법을 연구하였다. 새로운 TRAIL sensitizer로서 quercetin을 발굴하고, 이를 K562 세포에 TRAIL과 병용 투여하므로서 TRAIL의 효과 증강에 의한 내성극복을 시도하였다. Quercetin은 DNA-PK/Akt 신호전달경로를 억제하므로서, caspases 활성 증강과 PARP cleavage, 이에 따른 Bax의 발현을 증강시키는 기전으로 K562 세포의 TRAIL에 의한 apoptosis를 증대시키는 활성이 있음을 밝혔다. 이러한 quercetin 병용 처리에 의한 TRAIL의 활성 증강으로 TRAIL 내성이 극복됨을 CEM 세포에서도 확인하였다. 이러한 연구 결과는 DNA-PK 발현 증강에 의한 Akt의 활성화가 TRAIL 내성을 유발하는 기전을 토대로 함을 밝힘으로써, DNA-PK 활성 억제제를 TRAIL과 병용하므로서 TRAIL 내성을 나타내는 암세포에 내성 극복 효과를 얻을 수 있는 새로운 약제 병용 방법을 제시하였다.

• 한국미생물·생명공학회지
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• 제36권4호
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• pp.353-359
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• 2008

Hepatitis C virus (HCV) is known as the causative agent of blood transmitted hepatitis. Two viral proteins, E2 and NS5A, are known to exert interferon resistance of HCV via PKR pathway. Here, we report a third protein, the RNA-dependent RNA polymerase (NS5B) of HCV, induced interferon resistance inhibiting p56 pathway. p56 was shown to interact with p48 subunit of eukaryotic initiation factor 3 (eIF3). This interaction inhibited formation of ternary complex in translation initiation. Using dual reporter assay system, we observed that the translation decreased when interferon alpha was added to the culture. But, in the presence of HCV NS5B, the translation partly recovered. NS5B and p48 subunit of eIF3 were shown to interact. This interaction seems to inhibit the interaction between p48 and p56. This is the first report that a virus exerts interferon resistance via p56 pathway.

• Journal of Microbiology and Biotechnology
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• 제17권11호
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• pp.1856-1861
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• 2007

Physiological cell conditions such as glucose deprivation and hypoxia play roles in the development of drug resistance in solid tumors. These tumor-specific conditions cause decreased expression of DNA topoisomerase $II{\alpha}$, rendering cells resistant to topo II target drugs such as etoposide. Thus, targeting tumor-specific conditions such as a low glucose environment may be a novel strategy in the development of anticancer drugs. On this basis, we established a novel screening program for anticancer agents with preferential cytotoxic activity in cancer cells under glucose-deprived conditions. We recently isolated an active compound, AA-98, from Streptomyces sp. AA030098 that can prevent stress-induced etoposide resistance in vitro. Furthermore, LC-MS and various NMR spectroscopic methods identified AA-98 as mithramycin, which belongs to the aureolic acid group of antitumor compounds. We found that mithramycin prevents the etoposide resistance that is induced by glucose deprivation. The etoposide-chemosensitive action of mithramycin was just dependent on strict low glucose conditions, and resulted in the selective cell death of etoposide-resistant HT-29 human colon cancer cells.

• Molecules and Cells
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• 제26권3호
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• pp.258-264
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• 2008

A rice diacylglycerol kinase (DGK) gene, OsBIDK1, which encodes a 499-amino acid protein, was cloned and characterized. OsBIDK1 contains a conserved DGK domain, consisting of a diacylglycerol kinase catalytic subdomain and a diacylglycerol kinase accessory subdomain. Expression of OsBIDK1 in rice seedlings was induced by treatment with benzothiadiazole (BTH), a chemical activator of the plant defense response, and by infection with Magnaporthe grisea, causal agent of blast disease. In BTH-treated rice seedlings, expression of OsBIDK1 was induced earlier and at a higher level than in water-treated control seedlings after inoculation with M. grisea. Transgenic tobacco plants that constitutively express the OsBIDK1 gene were generated and disease resistance assays showed that overexpression of OsBIDK1 in transgenic tobacco plants resulted in enhanced resistance against infection by tobacco mosaic virus and Phytophthora parasitica var. nicotianae. These results suggest that OsBIDK1 may play a role in disease resistance responses.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.101.1-101
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• 2003

Lipopolysaccharide, siderophore, and cyclic dipeptide have been shown to be necessary for ISR induction by pseudomnads. However, there is no report on cloning of genes or generating specific mutants involving in ISR activity. A biological control bacteium P. chlororaphis O6 induces resistance to Erwinia carotovora subsp. carotovara SCCI in tobacco and induces drought resistance in Arabidopsis. To isolate genes involved in ISR activity and induction of drough resistance of O6, we constructed Tn5 mutants and were used to screen for ISR activity and drought resistance activity using microtiter assay with tobacco and Arabidopsis. Thirty-three ISR-deficient mutants were selected, and the nine ISR-deficient mutants were also lost activity of drought resistance. The flanking sequence analysis of the ISR and drought resistance-deficient mutants showed that a gacS gene encoding a two-component sensor kinase, and a mce gene encoding a protein involved in mycobacterial cell entry were mutated. The flanking sequence of each Tn5 mutant altered ISR activity is currently under investigation. These results indicate that gacS and mce are important genes in induction of ISR activity and drought resistance of P. chlororaphis O6. Our works will open opportunities for identification of bacterial genes or traits that are involved in ISR activity and induced drought resistance of P. chlororaphis O6.