• Journal of Applied Biological Chemistry
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• 제59권4호
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• pp.281-284
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• 2016

To handle the development of antifungal drug resistance, the development of new structural modules and new modes of action for antifungals have been highlighted recently. Here, the antifungal activity of quinonemethidal triterpenoids such as celastrol, dihydrocelastrol, iguestein, pristimerin, and tingenone isolated from Tripterygium regelii were identified (MIC $0.269-19.0{\mu}M$). C. glabrata was the most susceptible to quinonemethide among the tested fungi. Furthermore, quinonemethide suppressed cyctochrome c peroxidase expression dramatically, decreasing fungal viability caused by the accumulation of hydrogen peroxide. Thus, cyctochrome c peroxidase downregulation of quinonemethide may be a key mode of action for antifungals.

• 한국환경농학회지
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• 제28권4호
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• pp.435-441
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• 2009

In the present study, we analyzed the defensin protein deduced from Korean radish (Raphanus sativus L.) seeds.To express the genes in E. coli, we constructed a recombinant expression vector with a defensin gene, named rKRs-AFP gene isolated from Korean radish seeds. Over expressed rKRs-AFP proteins was separated by SDS-PAGE to determine the purity, and protein concentration was determined by the Bradford method. Antifungal activity was assessed by disk assay method against the tested fungi. As a result, when 500 mL of cell culture were disrupted by sonicator, 32.5 mg total proteins were obtained. The purified protein showed a single band on SDS-PAGE with estimated molecular weight about 6 KDa, consistent with the molecular mass calculated from the deduced amino acid sequence. The purified rKRs-AFP protein showed remarkable antifungal activities against several fungi including Aspergillus niger, Botrytis cinerea causing the gray mold disease, and Candida albicans. In field tests using the purified rKRs-AFP protein, the protein showed the reducing activity of disease spot and the mitigating effect of spreading of disease like agrichemicals. The immuno-assay of rKRs-AFP protein showed that the purified protein entirely accumulated at B. cinerea cytoplasm through the hyphal septa shown by fluorescence imaging. There was no fluorescence inside the cell, when the hypha was incubated without the protein. These all results indicate that the recombinant rKRs-AFP proteins can be utilized as a potential antifungal drug to control harmful plant fungal pathogens.

• Archives of Pharmacal Research
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• 제29권9호
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• pp.746-751
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• 2006

Amentoflavone is a plant biflavonoid that was isolated from an ethyl acetate extract of the whole plant of Selaginella tamariscina (Beauv.) spring. 1D and 2D NMR spectroscopy including DEPT, HMQC, and HMBC were used to determine its structure. Amentoflavone exhibited potent antifungal activity against several pathogenic fungal strains but had a very low hemolytic effect on human erythrocytes. In particular, amentoflavone induced the accumulation of intracellular trehalose on C. albicans as a stress response to the drug, and disrupted the dimorphic transition that forms pseudo-hyphae during pathogenesis. In conclusion, amentoflavone has great potential to be a lead compound for the development of antifungal agents.

• Fisheries and Aquatic Sciences
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• 제17권2호
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• pp.209-214
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• 2014

With the continuing demand for new solutions in the development of effective and safe candidiasis therapies, we investigated the efficacy of an antifungal agent from the marine brown alga Eisenia bicyclis. The methanolic extract of E. bicyclis evinced potential antifungal activity against Candida species. The ethyl acetate (EtOAc)-soluble extract from E. bicyclis demonstrated the strongest antifungal activity against Candida species among five solvent-soluble extracts. Indeed, the EtOAc-soluble extract showed minimum inhibitory concentrations (MICs) ranging from 4 to 8 mg/mL. Furthermore, the EtOAc-soluble extract considerably reversed high-level fluconazole resistance of Candida species. The MIC values of fluconazole against Candida species decreased substantially (from 64 to $4{\mu}g/mL$) in combination with the MIC of the EtOAc-soluble extract (4 mg/mL). The fractional inhibitory concentration indices of fluconazole ranged from 0.531 to 0.625 in combination with 4, 2, or 1 mg/mL of the EtOAc-soluble extract against Candida isolates, indicating that these combinations exert a marked synergistic effect against Candida isolates. These findings imply that compounds derived from E. bicyclis can be a potential source of natural antifungal agents against Candida species.

• Archives of Pharmacal Research
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• 제13권1호
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• pp.14-18
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• 1990

The carbinols, hydrazide, Schiff's bases and acryloyl derivatives of 2-thiobenzethiazole were prepared. The acid and nitrile of 20thiobenzothiazole were also obtained. The derivatives were tested for their antibacterial activities. Some derivatives showed the highest antifungal and activity.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2000년도 추계 학술발표회
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• pp.35.1-35
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• 2000

• Mycobiology
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• 제45권4호
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• pp.426-429
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• 2017

A yeast-like organism was isolated from a urine sample of a 6-year-old neutered male miniature poodle dog with urinary tract infection, diabetes ketoacidosis, and acute pancreatitis. We identified the yeast-like organism to be Candida glabrata and found that this fungus was highly resistant to azole antifungal drugs. To understand the mechanism of azole resistance in this isolate, the sequences and expression levels of the genes involved in drug resistance were analyzed. The results of our analysis showed that increased drug efflux, mediated by overexpression of ATP transporter genes CDR1 and PDH1, is the main cause of azole resistance of the C. glabrata isolated here.

• 한국식품과학회지
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• 제32권6호
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• pp.1258-1265
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• 2000

본 연구는 아플라톡신 생성균의 생육을 억제시킬 수 있는 길항 미생물을 분리하고 그 길항미생물을 이용한 된장 제조시 아플라톡신 제어 효과와 된장의 품질에 미치는 영향을 조사하였다. 아플라톡신 생성균인 Asp. flavus와 Asp. parasiticus에 대해 길항력이 가장 강력한 균을 분리하였으며 그 균은 Bacillus 속의 특성을 보였다. 분리한 길항균과 아플라톡신 생성균을 처리하여 제조한 된장의 아플라톡신 함량은 Asp. flavus을 처리하였을 때 아플라톡신 $B_1$이 27.2 ppb에서 길항균과 함께 처리로 87.5% 감소한 3.4 ppb였으며 Asp. parasiticus을 처리하였을 때 아플라톡신 $B_1$이 30.3 ppb에서 길항균과 함께 처리로 87.8% 감소한 3.7 ppb였다. 길항균과 아플라톡신 생성균을 처리한 된장의 유리지방산, 유리당, 유기산함량은 대조구와 큰 차이 없이 비슷하였다. 유리아미노산 총 함량은 길항균과 아플라톡신 생성균 처리로 다소 낮아지는 경향을 보였으나 큰 영향을 미치지 못하였다. 주로 glutamic acid, aspartic acid, tryptophan이 감소하였다. 된장의 향기성분은 아플라톡신 생성균을 처리하였을때 대조구에 비하여 큰 변화가 없었다. 그러나 길항균 처리로 변향인 2-pentyl furan와 불쾌취인 butanoic acid류가 소멸되거나 감소하고 octadecene 화합물은 생성 되었다. 결국 분리된 길항균은 아플라톡신 생성을 억제시켰으며 된장의 품질에는 그다지 영향을 미치지 않았다.

• Natural Product Sciences
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• 제13권3호
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• pp.258-262
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• 2007

The antifungal activity of the essential oil fraction from Thymus magus, and its major component thymol, against Candida albicans was investigated in vitro and in vivo. The combined effects of the oils and clotrimazole, a commonly used antifungal drug for treatment of external candidiasis, were evaluated in this study. In experimental vaginal candidiasis the essential oil fraction of T. magnus resulted in relatively milder inhibition of fungal growth following the inoculation of test mice compared to clotrimazole. However, new fungal growth was not detected up to 12 days after cessation of treatment. In contrast, in a similar experiment using clotrimazole, C. albicans was detected in the $12^{th}$ day post-treatment with the sample. This result indicates that T. magnus oil could be a promising drug to control vaginal candidiasis. In checkerboard titer tests, the combination of clotrimazole with the essential oil fraction of T. magus or T. quinquecostatus resulted in significant synergism, with FIC indices between 0.14 and 0.27 against C. albicans, while clotrimazole combined with thymol, the major component of these oils, produced only an additive effect, with FIC indices ranging between 0.50 and 1.00. Thus, the prominent synergistic effects of clotrimazole combined with T. magus essential oil indicate that these compounds may be an effective treatment for C. albicans infections.

• Mycobiology
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• 제42권1호
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• pp.52-58
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• 2014

A nucleoside diphosphate-linked moiety X (Nudix) hydrolase-like gene, YSA1, has been identified as one of the gromwell plant extract-responsive genes in Cryptococcus neoformans. Ysa1 is known to control intracellular concentrations of ADP-ribose or O-acetyl-ADP-ribose, and has diverse biological functions, including the response to oxidative stress in the ascomycete yeast, Saccharomyces cerevisiae. In this study, we characterized the role of YSA1 in the stress response and adaptation of the basidiomycete yeast, C. neoformans. We constructed three independent deletion mutants for YSA1, and analyzed their mutant phenotypes. We found that ysa1 mutants did not show increased sensitivity to reactive oxygen species-producing oxidative damage agents, such as hydrogen peroxide and menadione, but exhibited increased sensitivity to diamide, which is a thiol-specific oxidant. Ysa1 was dispensable for the response to most environmental stresses, such as genotoxic, osmotic, and endoplasmic reticulum stress. In conclusion, modulation of YSA1 may regulate the cellular response and adaptation of C. neoformans to certain oxidative stresses and contribute to the evolution of antifungal drug resistance.