• Korean Journal Plant Pathology
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• v.12 no.1
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• pp.72-79
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• 1996

보리로부터 분리한 Fusarium sp. BYA-1균주의 감자한천배지 배양체로부터 여러 식물병원곰팡이에 길항력을 나타내는 세 개의 항생물질을 분리하였다. 추출한 세 개의 항생물질은 silica gel관 크로마토그래피와 분취 HPLC, 그리고 Phytolhthora capsici 검정을 이용하여 정제하였다. 이들 분리한 항생물질들을 동정하기 위하여 융점 결정, 자외선흡광법, 질량분석 및 핵자기공명법 등의 기기분석을 실시하였다. 그 결과, 세 개의 항진균성 항생물질들은 fusarielin A, enniatin B, 그리고 enniatin B\ulcorner으로 각각 동정되었다. 분리한 세 개의 물질 중 fusarielin A가 공시된 곰팡이에 가장 강한 항균활성을 나타내었으며, 최소저해농도는 40$\mu\textrm{g}$/ml이하였다. Fusarium속 균주가 구조적으로 다른 두 종류의 항진균성 항생물질인 fusarielin A와 enniatins을 동시에 생성한다는 것은 본 논문에서 처음으로 보고하는 것이다.

• Korean Journal of Environmental Agriculture
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• v.15 no.4
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• pp.399-405
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• 1996

In the culture medium, the three antifungal fractions against P. capsici were separated by Sephadex G-25 column chromatography and Silica-gel chromatography. The substance A in white powder and the substance B in sticky oil were isolated by ethyl acetate : acetone mixture(7 : 3), and the substance C in yellow powder was isolated by chloroform : ethyl acetate mixture(95 : 5). The crude extract by ethyl acetate from the culture medium acidified to pH 2 was known to inhibit completely the growth of P. capsici at the level of $50mgkg^{-1}$. The substance A and B were known to be effective above the level of $5mgkg^{-1}$, and the substance C was effective above the level of $1mgkg^{-1}$. However, at the level of $20mgkg^{-1}$, the efficiency was in the order of A>C>B. It is apparent on a pot-experiment scale that the three substances effectively control Phytophthora blight of the red-pepper plant grown in the soil inoculated with P. capsici.

• Korean Journal of Microbiology
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• v.19 no.3
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• pp.108-114
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• 1981

In order to isolate microorganisms which produce antibiotics aganist wheat black rust, some bacteria, molds, and actinomycetes were isolated from soils and screened for the production of antibiptics against wheat black rust. Beacuse wheat black rust-puccinia graminis--is a complete parsitic mold which can't grow in artifical medium, new method for the screening of antibiotic producing microorgsnisms against wheat black rust developed by using live leaves of wheat. With new method, a strain No. $480HS_{20}$ which produces a substnace having strong and Puccinia graminis activity and very narrow antimicrobial spectrum was isolated. the substance produced by the strain No.$480HS_{20}$ had better anti Puccinia graminis activity than any other known antifungal antibotics such as kasurgamycin, balasticidins, actidione, antimycin, ologomycin. And the substance was observed to be very stable at heat and ultraviolet light. The strain was indentified as Bacillus subtilis.

• Research in Plant Disease
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• v.18 no.4
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• pp.354-360
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• 2012

This study tested the antifungal compound obtained from a medicinal plant, Dioscorea quinqueloba Thunb., in order to search the possibility of practical application of this product in agriculture through evaluating its activity using the citrus fruits. The extract of D. quinqueloba Thunb., which has the strongest antifungal activity, was selected as a candidate among 101 plant extracts. Based on this examination concerning antifungal activity of the product on Penicillium digitatum in vitro, it was confirmed its effect of mycelial growth inhibition showed over 87% at 0.5 mg/ml concentration. This natural product showed the stability of the substance, as it was not significantly influenced by pH, temperature, or ultraviolet radiation. While citrus fruits were stored at room temperature, P. digitatum was inoculated into them in order to prepare a similar environmental conditions with epidemic occurrence of the mold. As the result of our investigation, the disease preventive effects of the active antifungal substance evidenced a 100% at 0.5 mg/ml. When the phytotoxicity of the selected natural product on citrus at 2 mg/ml was assessed, we noted no toxic effects. Based on the superior preventive effects from this natural product extracted from the plant, it is presumed to be very useful in agricultural applications for the control of green mold, P. digitatum, which has been occurred often the biggest problem in the storage of citrus fruits.

• Animal Bioscience
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• v.34 no.6
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• pp.1029-1037
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• 2021

Objective: This study was conducted to investigate effects of antifungal substance and carboxylesterase-producing inoculant on fermentation indices and rumen degradation kinetics of whole crop rice (WCR) silage ensiled at different dry matter (DM) contents. Methods: Dual-purpose inoculants, Lactobacillus brevis 5M2 and Lactobacillus buchneri 6M1, confirmed both activities of antifungal and carboxylesterase in the previous study. The WCR at mature stage was chopped, and then wilted to obtain three different DM contents consisting of 35.4%, 43.6%, and 51.5%. All WCR forages were applied distilled water (CON) or mixed inoculants with 1:1 ratio at 1×105 colony forming unit/g (INO), and ensiled into 20 L mini silo (5 kg) in quadruplicates for 108 d. Results: The INO silages had lower lactate (p<0.001) and butyrate (p = 0.022) with higher acetate (p<0.001) and propionate (p<0.001) than those of CON silages. Ammonia-N (p<0.001), lactate (tendency; p = 0.068), acetate (p = 0.030), and butyrate (p<0.001) concentrations of INO silages decreased linearly with increasing DM content of WCR forage. The INO silages presented higher lactic acid bacteria (p<0.001) with lower molds (p<0.001) than those of CON silages. Yeasts (p = 0.042) and molds (p = 0.046) of WCR silages decreased linearly with increasing DM content of WCR forage. In the rumen, INO silages had higher the total degradable fraction (p<0.001), total volatile fatty acid (tendency; p = 0.097), and acetate (p = 0.007), but lower the fractional degradation rate (p = 0.011) and propionate (p<0.001) than those of CON silage. The total degradable fraction (p<0.001), total volatile fatty acid (p = 0.001), iso-butyrate (p = 0.036), and valerate (p = 0.008) decreased linearly with increasing DM content of WCR forage, while the lag phase (p<0.001) was increased linearly. Conclusion: This study concluded that application of dual-purpose inoculants on WCR silage confirmed antifungal and carboxylesterase activities by inhibiting mold and improving rumen digestibility, while increase of wilting times decreased organic acids production and rumen digestibility.

• Journal of Microbiology and Biotechnology
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• v.14 no.3
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• pp.525-531
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• 2004

A strain antagonistic to Fusarium solani, CHO104, was selected from approximately 100 microorganisms isolated from soil. Strain CHO104 was identified as Bacillus amyloliquefaciens and found to be Gram-positive based on the Biolog system and 16S rRNA methods. A culture broth of B. amyloliquefaciens CHO104 also exhibited antimicrobial activity against various microorganisms. As such, the EtOAc extract of the culture broth was isolated by various column chromatographic procedures and HPLC. The antimicrobial and antifungal substance was then characterized as macrolactin A $(C_{24}H_{34}O_5)$ using high-resolution EI-MS and NMR analyses, and found to be very effective in inhibiting the growth of Staphylococcus aureus, E. coli, and Botrytis cinerea, even when using a concentration of one-twentieth of the benzoic acid as the control compound.

• Mycobiology
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• v.45 no.1
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• pp.44-47
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• 2017

Ginseng damping-off, caused by the fungal pathogens Rhizoctonia solani and Pythium sp., is a critical disease in ginseng seedling. In a continuing effort to find microorganisms with the potential of acting as a biocontrol agent against Rhizoctonia damping-off, we found that a Streptomyces sp. A501 showed significant antifungal activity against Rhizoctonia solani. In field experiment to test the efficacy of Streptomyces sp. A501 in controlling ginseng damping-off, the incidence of damping-off disease was meaningfully reduced when ginseng seeds were soaked in the culture broth of Streptomyces sp. A501 before sowing. To perform characterization of the antifungal compound, we isolated it from the culture broth of strain A501 through Diaion HP-20 and silica gel column chromatographies and preparative high-performance liquid chromatography. The structure of the antifungal compound was assigned as fungichromin by spectroscopic methods, mainly nuclear magnetic resonance and electrospray ionization-mass analysis.

• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.887-896
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• 2015

To develop environment-friendly agricultural products with anti-microbial activity against Sclerotinia sclerotiorum as a pathogen of sclerotium disease, Usnea longissima was extracted by methanol and its extract was fractionated into several solvent fractions. The chloroform fraction, which showed the highest antimicrobial activity, was separated by silica gel-column chromatography and obtained into nine group subfractions. The nine group fractions were searched the antifungal activities by bioassay. The most active No. 3 subfraction was analyzed by GC-MS. Each mass spectra, corresponding to each peak of chromatogram, was compared to database of Wiley library. As a result, Usnic acid was identified as main compounds. In conclusion, Usnic acid isolated from Usnea longissima was antimicrobial chemical against Sclerotinia sclerotiorum as a pathogen of sclerotium disease.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.81-88
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• 1990

For the selection of powerful antagonistic bacterium for biological control of soilborne Fusarium solani causing root rot of many important crops, the best YPL-1 strain was selected among 300 strains of bacteria isolated from rhizosphere in ginseng root rot-suppressive soil. The strain was identified to be a species to Pseudomonas stutzeri. With in vitro fungal inhibition tests, antagonistic substance of P. stutzeri YPL-1 against F. solani was presumed to be heat unstable, macromolecular substances such as protein. Also, it was shown that antifungal activity of P. stutzeri YPL-1 increased in proportion to its chitinase production. P. stutzeri YPL-M122 (chi-, lam -) which was deprived of the productivity of chitinase and laminarinase by NTG mutagenesis had lost antifungal activity, completely. And P. stutzeri YPL-MI53 (chi-) had only 4.1% of its antifungal activity. P. stutzeri YPL-1 was not able to produce any extracellular siderophore in iron-deficent minimal medium. It is confident that the antifungal mechanism of P. stutzeri YPL-1 for biocontrol of F. solani depends on lysis rather than antibiosis :the mechanism of lysis appears to involve enzymatic degradation of the cell will components of F. solani by hydrolytic enzymes of more chitinase and less laminarinase.

• Microbiology and Biotechnology Letters
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• v.37 no.1
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• pp.10-16
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• 2009

Polymerase chain reactin (PCR) could be a simple way to screen new microbial strains producing useful secondary metabolites if their biosynthetic genes are known and candidate strains to be screened are available. In this study, we have screened two myxobacterial strains, KYC3047 and KYC3076, carrying genes appeared to be biosynthetic genes of soraphen A, a potent antifungal substance, out of 50 cellulose degrading myxobacteria using PCR. The two strains were identified as Sorangium cellulosum based on morphological, physiological, and molecular biological characteristics. Both of the strains produced substances having strong antifungal activities as expected against Candida albicans, a causative agent of candidiasis, and Colletotrichum acutatum, a causative agent of anthracnose on pepper.