• 한국자기공명학회논문지
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• 제8권2호
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• pp.115-126
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• 2004

Four secondary metabolites from an unidentified tunicate were isolated by treatment with trichloroethyl chloroformate(TECF) or acetic anhydride in pyridine. Their structures were determined by an extensive NMR analysis and the configuration of diacetyl derivatives(3a, 4a) was assigned by comparing with NMR data of a similar compound. Three new naturally occurring compounds (1, 3, 4) showed potent brine shrimp lethality and antifungal effect against Candia albicans.

• 미생물학회지
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• 제49권2호
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• pp.165-171
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• 2013

순천대학교 지의류 은행(Lichen Bioresources Center)에서 571종의 지의류 내생 곰팡이를 분양받아 Candida albicans에 대한 항진균 활성을 조사하여 4종을 선정하였다. 선정된 4종의 지의류 내생 곰팡이의 배양액 내에 존재하는 항진균 활성을 알아보기 위해 disc diffusion method 방법을 이용한 결과 Stereocaulon sp. (1429,1430)가 C. albicans에 대한 항진균 활성이 가장 좋았으며, 다음으로는 Graphis sp. (1245), Cryptosporiopsis diversispora (0156) 순으로 활성이 좋게 나타났으며, 이들 지의류 내생곰팡이가 고체배지와 액체배지에서도 항진균 활성 물질을 생성하였다. 고체배지에서와 액체배지에서 공통적으로 활성이 있는 지의류 내생 곰팡이 배양액의 chloroform, ethyl acetate 용매 추출물의 C. albicans의 항진균 활성도를 측정한 결과 4종 모두 chloroform 추출물에서 높은 활성도를 나타냈다. Candida albicans, Candida glabrata, Candida tropicalis, Candida lusitaniae에 대한 항진균 활성은 Stereocaulon sp. (1429, 1430)의 chloroform 추출물에서 모두 98% 이상의 높은 저해율을 보였고 Stereocaulon sp. (1429) 배양액의 chloroform 추출액과 ethyl acetate 추출액을 GC/MS를 이용해 성분을 분석한 결과 hexadecanonic acid-methyl ester, 14-octadecenoic acid-methyl ester, octadecenoic acid-methyl ester가 새로운 항진균 물질일 가능성을 보여주었다.

• 한국미생물·생명공학회지
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• 제37권4호
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• pp.340-349
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• 2009

메주로부터 항진균 및 항세균 활성을 나타내는 균주를 분리하고 동정하여 B. polyfermenticus CJ9로 명명하였다. B. polyfermenticus CJ9의 생육에 따른 항균 활성을 측정한 결과 항세균 활성은 배양 12시간에 최대 활성을 나타내며 72시간까지 90% 이상 활성을 유지하다 120시간에 활성을 완전히 상실하였다. 항진균 활성은 배양 24시간 이후부터 최대 활성을 나타내었고, 사멸기 이후 활성이 다소 감소되었으나 배양 120시간까지 활성이 유지되었다. B. polyfermenticus CJ9은 식품과 인체에 유해한 곰팡이, 효모, 그람 양성 및 음성 세균에 대한 항진균 활성과 항세균 활성을 동시에 나타내었다. B. polyfermenticus CJ9의 항세균 활성은 $37^{\circ}C$ 에서 24시간 열처리 후에 활성을 상실하였으며, pH 5.0~9.0 구간에서는 안정한 활성을 나타내었으나 pH 3.0~4.0 구간에서 활성이 감소하였다. 항진균 물질은 $121^{\circ}C$에서 15분간 열처리시 활성이 감소되었으나 역가가 완전히 소실되지 않았으며, pH 3.0~9.0 구간에서 안정한 활성을 나타내었다. 항세균 물질과 항진균 물질은 proteinase K, protease, trypsin, $\alpha$-chymotrypsin 등의 단백분해효소 처리로 역가를 상실하거나 일부 감소되어 단백질성 물질임을 추정하였다. B. polyfermenticus CJ9의 항세균 물질과 항진균 물질을 $C_{18}$ Sep-Pak column에 흡착된 분획으로부터 역가를 확인하여 소수성 물질임을 알 수 있었으며, Tricine-SDS-PAGE 및 direct detection 실험을 통하여 분자량을 확인한 결과 항진균 물질은 약 1.4 kDa의 물질임을 확인하였다. 그러나 항세균 활성 물질은 열 불안정성 때문에 동 실험법상에서 그 분자량을 확인할 수 없었다. B. polyfermenticus CJ9이 생산하는 항균 물질은 항세균 및 항진균 활성을 동시에 가지는 단백질성 물질로서 천연 식품보존제 및 정장제재로 활용이 기대되며, 이를 위하여 항세균 물질과 항진균 물질의 정제 및 구조분석 등의 연구가 필요하다.

• 한국미생물·생명공학회지
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• 제40권1호
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• pp.23-29
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• 2012

순천대학교 지의류생물 소재은행(KOLABIC)에서 100종의 지의류 내생 곰팡이를 분양 받아 C. albicans에 대한 항진균 활성을 조사하였다. 고체배지 및 액체배지에 배양시 Usnea rigidula, Parmotrema pseudotinctorum 그리고 Myelochroa sp.가 높은 항진균 활성을 나타내는 물질을 생성함을 알 수 있었다. 이들 3종 지의류 내생 곰팡이의 배양액을 chloroform, ethyl acetate 용매 순으로 추출하고 disc diffusion method를 이용하여 각 추출물의 C. albicans에 대한 항진균 활성도를 측정한 결과 모두 chloroform 추출물에서 높은 활성이 가장 높았으며, 다음으로 ethyl acetate 추출물이 높은 활성을 나타냈다. 항진균성 물질이 기존에 알려진 물질인지에 대한 정보를 알기위해 6 일 동안 배양한 Usnea rigidula와 4일 동안 배양한 Parmotrema pseudotinctorum의 chloroform 추출액에 대하여 HPLC, $C_{18}$ column으로 분리하여 Usnea rigidula (2326)의 6일과 Parmotrema pseudotinctorum (2202)의 4일 배양액에서 각각 2 개의 peak 분획물을 얻었다. 각 분획물을 농축한 후 96 well plate를 이용하여 C. albicans와 C. glabrata에 대한 항진균 활성을 실험한 결과, Parmotrema pseudotinctorum의 주요peak는 control에 비해 항진균 활성이 높게 나타났으며 활성물질은 usnic acid계열의 화합물로 추정되었다.

• The Plant Pathology Journal
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• 제31권3호
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• pp.278-289
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• 2015

Indigenous strains of Trichoderma species isolated from rhizosphere soils of Tea gardens of Assam, north eastern state of India were assessed for in vitro antagonism against two important tea fungal pathogens namely Pestalotia theae and Fusarium solani. A potent antagonist against both tea pathogenic fungi, designated as SDRLIN1, was selected and identified as Trichoderma viride. The strain also showed substantial antifungal activity against five standard phytopathogenic fungi. Culture filtrate collected from stationary growth phase of the antagonist demonstrated a significantly higher degree of inhibitory activity against all the test fungi, demonstrating the presence of an optimal blend of extracellular antifungal metabolites. Moreover, quantitative enzyme assay of exponential and stationary culture filtrates revealed that the activity of cellulase, ${\beta}$-1,3-glucanase, pectinase, and amylase was highest in the exponential phase, whereas the activity of proteases and chitinase was noted highest in the stationary phase. Morphological changes such as hyphal swelling and distortion were also observed in the fungal pathogen grown on potato dextrose agar containing stationary phase culture filtrate. Moreover, the antifungal activity of the filtrate was significantly reduced but not entirely after heat or proteinase K treatment, demonstrating substantial role of certain unknown thermostable antifungal compound(s) in the inhibitory activity.

• The Plant Pathology Journal
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• 제18권2호
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• pp.102-105
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• 2002

A strain of Acremonium strictum, the mycoparasite of Botrytis cinerea, showed strong antifungal activities both in vitro and in vivo against several phytopathogenic fungi. An antifungal substance was purified from the liquid cultures of A. strictum and identified as verlamelin by instrumental analyses. Verlamelin exhibited in vitro antifungal activity against some phytopathogenic fungi such as Magnaporthe grisea, Bipolaris maydis, and Botrytis cinerea, while it was net active against all the bacteria tested. In viva, verlamelin exhibited strong protective and curative activities, particularly against barley powdery mildew. At 100 μg/ml, it inhibited the development of barley powdery mildew with control values of more than 90% in 7-day protective and 2-day curative applications. This is the first report on the production of verlamelin by Acremonium species.

• Mycobiology
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• 제40권1호
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• pp.59-65
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• 2012

Antagonistic microorganisms against $Rhizoctonia$ $solani$ were isolated and their antifungal activities were investigated. Two hundred sixteen bacterial isolates were isolated from various soil samples and 19 isolates were found to antagonize the selected plant pathogenic fungi with varying degrees. Among them, isolate C9 was selected as an antagonistic microorganism with potential for use in further studies. Treatment with the selected isolate C9 resulted in significantly reduced incidence of stem-segment colonization by $R.$ $solani$ AG2-2(IV) in Zoysia grass and enhanced growth of grass. Through its biochemical, physiological, and 16S rDNA characteristics, the selected bacterium was identified as $Bacillus$ $subtilis$ subsp. $subtilis$. Mannitol (1%) and soytone (1%) were found to be the best carbon and nitrogen sources, respectively, for use in antibiotic production. An antibiotic compound, designated as DG4, was separated and purified from ethyl acetate extract of the culture broth of isolate C9. On the basis of spectral data, including proton nuclear magneric resonance ($^1H$ NMR), carbon nuclear magneric resonance ($^{13}C$ NMR), and mass analyses, its chemical structure was established as a stereoisomer of acetylbutanediol. Application of the ethyl acetate extract of isolate C9 to several plant pathogens resulted in dose-dependent inhibition. Treatment with the purified compound (an isomer of acetylbuanediol) resulted in significantly inhibited growth of tested pathogens. The cell free culture supernatant of isolate C9 showed a chitinase effect on chitin medium. Results from the present study demonstrated the significant potential of the purified compound from isolate C9 for use as a biocontrol agent as well as a plant growth promoter with the ability to trigger induced systemic resistance of plants.

• Mycobiology
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• 제45권1호
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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.

• The Plant Pathology Journal
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• 제24권4호
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• pp.461-468
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• 2008

An endophytic bacterial strain YC5480 producing antifungal and phytotoxic compounds simultaneously was isolated from the surface sterilized root of Artemisia sp. collected at Jinju area, Korea. The bacterial strain was identified as a species of Pseudomonas brassicacearum based on its 16S rRNA gene sequence analysis and physiological and biochemical characteristics. The seed germination and growth of monocot and dicot plants were inhibited by culture filtrate (1/10-strength Tryptic Soy Broth) of the strain. The germination rate of radish seeds in the culture filtrate differed in various culture media. Only 20% of radish seeds germinated in the culture media of 1/2 TSB for 5 days incubation. Mycelial growth of fungal pathogens, Colletotrichum gloeosporioides, Fusarium oxysporum and Phytophthora capsici was also inhibited by the culture filtrate of the strain YC5480. An antifungal compound, KS-1 with slight inhibitory activity of radish seed germination at 1,000 ppm and a seed germination inhibitory compound, KS-2 without suppression of fungal growth were produced simultaneously in TSB. The compounds KS-1 and KS-2 were identified to be 2,4-diacetylphloroglucinol (DAPG) and 2,4,6-trihydroxyacetophenone (THA), respectively.

• 농약과학회지
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• 제7권1호
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• pp.51-57
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• 2003

신농약 개발을 목적으로 isosterism 이론을 근거로 하여 선도화합물인 2-imino-1,3-thiazoline 의 분자 수정을 통하여 분자내에 1,3-thiazoline과 urea기가 포함된 새로운 화합물 4를 디자인하였다. N-Alkylthiourea 5와 bromoacetonitrile을 에탄올 용액 중에서 반응시켜 위치 선택적으로 생성된 2,4-diimino-1,3-thiazolidine 브롬산 염 6을 isocyanate 유도체와 반응하여 화합물 4의 tautomer인 화합물 8을 얻었다. 합성된 화합물 13종을 대표적인 6종의 식물병원균, 벼 도열병, 벼 잎집무늬마름병, 오이 잿빛곰팡이병, 토마토 역병, 밀 붉은녹병, 보리 흰가루병 등에 대한 in vivo 항균력 시험을 하였다. 합성된 화합물 8의 벼 도열병원균에 대한 항균력은 2-phenylimino-1,3-thiazoline 1과 비교할 때 매우 낮았으며, 일부 화합물에서 밀붉은녹병에 대한 미약한 항균력을 나타냈다.