• Title/Summary/Keyword: Antifungal protein

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In Vitro Antifungal Activity and Mode of Action of 2',4'-Dihydroxychalcone against Aspergillus fumigatus

  • Seo, Young Ho;Kim, Sung-Su;Shin, Kwang-Soo
    • Mycobiology
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    • v.43 no.2
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    • pp.150-156
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    • 2015
  • 2',4'-Dihydroxychalcone (2',4'-DHC) was identified from a heat shock protein 90 (Hsp90)-targeting library as a compound with Hsp90 inhibitory and antifungal effects. In the presence of 2',4'-DHC ($8{\mu}g/mL$), radial growth of Aspergillus fumigatus was inhibited 20% compared to the control, and green pigmentation was completely blocked. The expression of the conidiation-associated genes abaA, brlA, and wetA was significantly decreased (approximately 3- to 5-fold) by treatment with 2',4'-DHC. The expression of calcineurin signaling components, cnaA and crzA, was also significantly reduced. The inhibitory effects of 2',4'-DHC on metabolic activity and mycelial growth were significantly enhanced by combination treatment with itraconazole and caspofungin. Docking studies indicated that 2',4'-DHC bind to the ATPase domain of Hsp90. These results suggest that 2',4'-DHC act as an Hsp90-calcinurin pathway inhibitor.

Wicaltin, a New Protein Toxin Secreted by the Yeast Williopsis californica and Its Broad-Spectrum Antimycotic Potential

  • Theisen, Simone;Molkenau, Elisabeth;Schmitt, Manfred J.
    • Journal of Microbiology and Biotechnology
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    • v.10 no.4
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    • pp.547-550
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    • 2000
  • The yeast Williopsis californica was shown to secrete a unique broad-spectrum killer toxin (Wicaltin) with antifungal activity against 14 yeast genera, including yeast-like and mycelial forms of the human pathogens Candida albicans and Sporothrix schenkii. Agar diffusion bioassays indicated that its activity was more pronounced than the antifungal potential of frequently used antimycotics; 0.07 pmol Wicaltin showed the same toxicity as 0.2 pmol miconazole and 29 pmol clotrimazole. Since the toxin's primary target would appear to be the yeast cell wall, Wicaltin may be attractive in combatting clinically relevant yeast and fungal infections.

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Antifungal Activity and Plant Growth Promotion by Rhizobacteria Inhibiting Growth of Plant Pathogenic Fungi (식물병원성 진균을 억제하는 근권세균의 항진균능과 식물생장촉진능)

  • Jung, Taeck-Kyung;Kim, Ji-Hyun;Song, Hong-Gyu
    • Korean Journal of Microbiology
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    • v.48 no.1
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    • pp.16-21
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    • 2012
  • Since many pesticides cause various health and environmental problems, alternative measures to replace them are needed, and the bacteria producing the antifungal substances can be one of them. In this study, several rhizobacteria were isolated and their antifungal activities against some important plant pathogenic fungi were examined. Pseudomonas otitidis TK1 and Paenibacillus peoriae RhAn32 inhibited the growth of Fusarium oxysporum f. sp. niveum and F. oxysporum f. sp. lycopersici by 49.8% and 45.6%, and 45.1% and 48.3%, respectively compared to those of the control. P. peoriae RhAn32 also decreased the growth of F. oxysporum f. sp. raphani by 37.5%. This growth inhibition might be due to the production of antifungal substances, such as siderophore, hydrogen cyanide and chitinase, which were produced by these rhizobacteria. P. otitidis TK1 also produced plant growth hormones indole acetic acid and indole butyric acid at $293.41{\mu}g/mg$ protein and $418.53{\mu}g/mg$ protein, respectively. When P. otitidis TK1 and B. cereus TK2 were inoculated together with F. oxysporum f. sp. lycopersici to the 4 weeks grown tomato seedlings and incubated additional 8 weeks, the stem lengths of tomato increased up to 45.7% and 55.3% and root lengths were raised to 64.9% and 60.8%, respectively than those of the control group. The wet weights increased by 118% and 182%, respectively compared to the control group.

Crystal Structure of Osmotin, a Plant Antifungal Protein

  • Kyeongsik Min;Ha, Sung-Chul;Yun, Dae-Jin;Kim, Kyeong-Kyu
    • Proceedings of the Korean Biophysical Society Conference
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    • 2002.06b
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    • pp.29-29
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    • 2002
  • In response to fungal invasion and other signals, plants accumulate a number of proteins that are involved in defense against pathogens. Osmotin is a 24 kDa protein belonging to the pathogenesis-related (PR) protein, a component of the hypersensitive response in leaves of tobacco plants exposed to tobacco mosaic virus.(omitted)

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Investigation of the Antifungal Activity and Mechanism of Action of LMWS-Chitosan

  • Park, Yoon-Kyung;Kim, Mi-Hyun;Park, Seong-Cheol;Cheong, Hyeon-Sook;Jang, Mi-Kyeong;Nah, Jae-Woon;Hahm, Kyung-Soo
    • Journal of Microbiology and Biotechnology
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    • v.18 no.10
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    • pp.1729-1734
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    • 2008
  • Chitosan, a cationic polysaccharide, has been widely used as a dietary supplement and in a variety of pharmacological and biomedical applications. The antifungal activity and mechanism of action of low molecular weight water-soluble chitosan (LMWS-chitosan) were studied in fungal cells and vesicles containing various compositions of fungal lipids. LMWS-chitosan showed strong antifungal activity against various pathogenic yeasts and hyphae-forming fungi but no hemolytic activity or cytotoxicity against mammalian cells. The degree of calcein leakage was assessed on the basis of lipid composition (PC/CH; 10:1, w/w). Our result showing that LMWS-chitosan interacts with liposomes demonstrated that chitosan induces leakage from zwitterionic lipid vesicles. Confocal microscopy revealed that LMWS-chitosan was located in the plasma membrane. Finally, scanning electron microscopy revealed that LMWS-chitosan causes significant morphological changes on fungal surfaces. Its potent antibiotic activity suggests that LMWS-chitosan is an excellent candidate as a lead compound for the development of novel anti-infective agents.