• 농약과학회지
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• 제16권3호
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• pp.209-216
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• 2012

계혈등으로부터 6종의 항균활성물질을 분리 정제하여 화학구조를 결정하였다. 계혈등 시료를 음건하여 80% aq. MeOH로 추출하고 감압 농축한 후 n-hexane, EtOAc, n-BuOH, 그리고 $H_2O$ 층으로 분획하였다. 각 분획을 이용하여 벼 도열별, 벼 잎집무늬마름병, 토마토 잿빛곰팡이병, 토마토 역병, 밀 붉은녹병, 보리 흰가루병 등 6가지 식물병에 대하여 식물병 방제효과를 검정한 결과, EtOAc 층이 가장 강한 활성을 보였으며, 벼 도열병, 토마토 잿빛 곰팡이병, 토마토 역병 및 보리 흰가루병에 대하여 80% 이상의 활성을 보였다. EtOAc층을 대상으로 silica gel chromatography 및 preparative TLC, HPLC 등을 이용하여 6종의 화합물을 분리, 정제하고 $^1H$-NMR, $^{13}C$-NMR, ESI-MS/MS, HMQC, $^1H-^1H$ COSY의 기기분석을 통해 ethanone, hydroxytyrosol, epicatechin, procyanidin B-2, dimethoxy daizein과 formononetin 으로 구조를 동정하였다. Epicatechin을 제외한 나머지 화합물들은 계혈등에서 처음으로 분리되었다. 분리한 물질들의 in vitro 및 in vivo 항균활성에 대한 연구를 진행하고 있다.

• 식물병연구
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• 제8권1호
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• pp.1-10
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• 2002

2001년 기상의 특징은 3월부터 5월까지 계속된 극심한 가뭄과 생육기간 내내 계속된 고온현상 그리고 별다른 태풍의 내습 없이 9, 10월 수확기 맑은날의 지속으로 요약할 수 있다. 벼는 순조로운 기상 때문에 잎, 이삭도열병, 세균성벼알마름병, 흰잎마름병, 잎집무늬마름병의 발생이 예년에 비해 경미하였으나, 감비추진 정책에 의해 생육후기 깨씨무늬병이 발생하여 전국적으로 문제시되었으며 그동안 발생이 적었던 줄무늬잎마름병이 경기, 충청, 호남 서해안지역을 중심으로 많이 발생하였다. 고추는 생육기 비가 많이 왔던 전남북 지역에서 역병 발생이 심하였으며 토마토와 오이는 대부분 예년에 비해 병발생이 적었다. 수박의 경우는 꽃자리 부분이 썩는 푸른곰팡이병이 전국적으로 발생하였으며 CGMMV는 전년에 비해 상당폭 발생면적이 감소하였고 노지재배의 경우 탄저병 발생이 예년에 비해 심하였다. 참외와 딸기도 전년에 비하여 병발생이 경미하였으며 예년에 발생이 많았던 참외의 급성위조증상도 발생이 대폭 감소하였다. 마늘·양파의 흑색썩음균핵병은 봄철의 가뭄과 고온현상으로 병발생의 전년의 절반수준으로 감소하였다. 감자의 풋마름병은 발병포장이 증가하는 경향이었으며 고구마의 덩굴쪼김병도 발생이 감소하였다. 사과의 경우 전반적으로 병 발생이 예년에 비해 경미하였으며 배는 흰가루병이 많이 발생하였다. 맥류의 붉은곰팡이병은 예년처럼 거기 발생이 없었다.

• 농약과학회지
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• 제5권2호
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• pp.26-32
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• 2001

새로운 농약살균제의 개발을 목적으로 trifluoromethyl기 dihydro-1,4-dithiin기 포함된 ${\alpha},{\beta}$-불포화 carboxamide 유도체 12를 합성하였다. trifluoromethylated ${\beta}$-ketoester 유도체 4를 염화한 다음 1,2-ethandithiol과 반응시켜 중간체 1,4-dithiane 유도체 9를 얻었다. 중간체 9의 정제없이 hydroxy기를 염소로 치환하여 생성된 중간체 8을 triethylamine 존재하에서 탈염화하여 trifluoromethyl기가 포함된 dihydro-1,4-dithiin ethyl ester 7을 합성하였다. Ester 7을 가수분해하여 생성된 carboxylic acid 10의 hydroxy를 염소로 치환하여 활성화한 다음 여러 가지 amine 유도체와 반응시켜 trifluoromethyl기가 포함된 dihydro-1,4-dithiin carboxamide 유도체 12를 합성하였다. 합성된 화합물을 대표적이 6종의 식물병원균, 벼 도열병원균, 벼 잎집무늬마름병원균, 오이 잿빛곰팡이병원균, 토마토 역병원균, 밀붉은녹병원균, 보리 흰가루병원균 등에 대한 항균력을 시험 (in vivo) 하였다. 그 결과, 대부분의 화합물이 미약한 항균을 나타냈다. 페닐기의 meta 위치에 isopropy기가 치환된 화합물 12h는 250 ppm에서 밀 붉은녹병원균에 대한 항균력 (99%)을 나타냈다.

• Fisheries and Aquatic Sciences
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• 제4권4호
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• pp.201-207
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• 2001

To study the distribution of organophosphorus pesticides which are extensively used for agriculture in Korea. Sea water samples were taken from 4 coastal areas during May and August of 1997 and sediment samples were collected from two coastal areas in August of 1997. These samples were analyzed using a Gas Chromatography/Nitrogen Phosphorus Detector (GC/NPD). In August the most commonly found organophosphorus pesticides in the surface waters of Kunsan area were IBP < S-Benzyl O,O-di-isopropyl phosphorothioate > $(m=432.5ng\;L^{-1})$ and EDDP < O-ethyl S,S-diphenyl phosphorodithioate > $(m=37.4ng\;L^{-1}) $ which are largely used between June and September to prevent rice blast disease. In Danghang Bay, dry fields located near the mouth of the estuary seemed to affect the concentrations of certain organophosphorus pesticides in the surface waters. Since organophosphorus pesticides applied in the watershed are rapidly decomposed while being transported along freshwater streams, watershed size is not proportional to the concentrations of these pesticides in the coastal waters. Pesticides concentrations measured in August were compared with those in May. IBP concentrations in coastal waters were about an order of magnitude higher in August than in May. Temporal and geographical distribution of individual organophosphorus pesticides is likely to be affected by types of agricultural practices in the watershed. Chloropyrifos was the most important of the organophosphorus pesticides in the sediments of the study area because of its persistent nature and high affinity to particulates.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.84.2-85
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• 2003

Magnaporthee grisea causes the devastating blast disease of rice. Entensive research has been conducted on infection mechanisms, particularly on appressorium formation and penetration, of this fungus during the last decade. However, the role(s) of cell-wall-degrading enzymes (CWDEs) on pathogenesis is not clearly demonstrated at molecular level. Many CWDES in plant pathogenic fungi including M. grisea are redundant; that is, there are multiple genes encoding enzymes with a similar or overlapping spectrum of activities. It is laborious to isolate all of the genes encoding related enzymes and to construct mutants lacking all 9f them. Thus, we considered alternative strategies to address the role of CWDEs in pathogenesis. Since expression of CWDE genes Is repressed by a simple sugar, as the first step, we cloned a Snfl (sucrose non-fermenting) gene (MgSnf1) from M. grisea. The predicted amino acid sequence showed a high identity with other Snf1 genes from various fungi. To elucidate molecular function of MgSnf1, a transformant lacking MgSnf1 was created by targeted gene replacement. En glucose, sucrose, and xylan the MgSnf1 mutant grew normally but in pectin and complex media, it grew slower than wild type. Expression of various CWDEs in MgSnf1 mutant was investigated and found that expression of some CWDEs is repressed. However, no significant difference was observed in conidial germination, appressorium formation, and pathogenicity in MgSnf1 mutant. However, MgSnf1 functionally complemented a yeast MgSnf1 mutant. These results suggest that MgSnf1 is involved in regulation of CWDEs and MgSnf1 is dispensable in pathogenicity of M. grisea.

• Genomics & Informatics
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• 제10권1호
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• pp.58-64
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• 2012

Intron prediction is an important problem of the constantly updated genome annotation. Using two model plant (rice and $Arabidopsis$) genomes, we compared two well-known intron prediction tools: the Blast-Like Alignment Tool (BLAT) and Sim4cc. The results showed that each of the tools had its own advantages and disadvantages. BLAT predicted more than 99% introns of whole genomic introns with a small number of false-positive introns. Sim4cc was successful at finding the correct introns with a false-negative rate of 1.02% to 4.85%, and it needed a longer run time than BLAT. Further, we evaluated the intron information of 10 complete plant genomes. As non-coding sequences, intron lengths are not limited by a triplet codon frame; so, intron lengths have three phases: a multiple of three bases (3n), a multiple of three bases plus one (3n + 1), and a multiple of three bases plus two (3n + 2). It was widely accepted that the percentages of the 3n, 3n + 1, and 3n + 2 introns were quite similar in genomes. Our studies showed that 80% (8/10) of species were similar in terms of the number of three phases. The percentages of 3n introns in $Ostreococcus$ $lucimarinus$ was excessive (47.7%), while in $Ostreococcus$ $tauri$, it was deficient (29.1%). This discrepancy could have been the result of errors in intron prediction. It is suggested that a three-phase evaluation is a fast and effective method of detecting intron annotation problems.

• The Plant Pathology Journal
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• 제15권1호
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• pp.14-20
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• 1999

Twenty isolates of Helminthosporium species were obtained from various grass plants and tested for controlling efficacy on the development of plant diseases. An isolate of Helminthosporium sp. TP-4 was chosen and six antibiotic substances were purified from cultures of the fungus by repeated silica gel column chromatography and preparative thin-layer chromatography. They were identified as ophiobolin a, 6-epiophiobolin A, 3-anhydroophiobolin A, 3-anhydro-6-epiophiobolin A, iphiobolin B, and iphiobolin I mainly by mass spectrometry and nuclear magnetic resonance spectrometry. Ophiobolins inhibited the growth of a grampositive bacterium Streptomyces griseus, but were not active against gram-negative bacteria. They also showed an antifungal activity. In in vivo tests, iphiobolin B exhibited potent controlling activities against rice blast, tomato late blight, and wheat leaf rust with control values more than 90% and 70% at concentration of $500\mu\textrm{m}$/ml and 100 ${\mu}{\textrm}{m}$/ml. Ophiobolin A and 6-epiophiobolin A controlled the development of wheat leaf rust more than 80% at concentrations of 100 /ml and $500\mu\textrm{m}$/ml respectively. 3-Anhydro-6-epiophiobolin A was not active against any plant disease. On the other hand, the A-series ophiobolins other than 3-anhydroophiobolin A showed stronger phytotoxic activity in a leaf-wounding assay using 8 plant species than those of 3-anhydroophiobolin A, ophiobolin B, and ophiobolin I. The results indicate that there is little correlation between antifungal activity and phytotoxicity of ophiobolins.

• The Plant Pathology Journal
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• 제22권1호
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• pp.75-89
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• 2006

The actinomycete strain JK-1 that showed strong inhibitory activity against some plant pathogenic fungi and oomycetes was isolated from Jung-bal Mountain in Ko-yang, Korea. The strain JK-1 produced spores singly borne on sporophores and the spores were spherical and 0.9-1.2 11m in diameter. The cell wall of the strain JK-1 contained meso-diaminopimelic acid. The actinomycete strain JK-1 was identified as the genus Micromonospora based on the morphological, physiological, biochemical and chemotaxonomic characteristics. From the 168 rDNA analysis, the strain JK-1 was assigned to M aurantiaca. The antibiotic MA-1 was purified from the culture broth of M aurantiaca JK-1 using various purification procedures, such as Diaion HP20 chromatography, C18 flash column chromatography, silica gel flash column chromatography and Sephadex LH-20 column chromatography. $^{1}H-$, $^{13}C-NMR$ and EI mass spectral analysis of the antibiotic MA-1 revealed that the antibiotic MA-1 is identical to phenylacetic acid. Phenylacetic acid showed in vitro inhibitory effects against fungal and oomycete pathogens Alternaria mali, Botrytis cinerea, Magnaporthe grisea, Phytophthora capsici and yeast Saccharomyces cerevisiae at < 100 $\mug$ $ml^{-1}$. In addition, phenylacetic, acid completely inhibited the growth of Sclerotinia sclerotiorum, Bacillus subtilis, Candida albicans, Xanthomonas campestris pv. vesicatoria at < $\mug$ $ml^{-1}$. Phenylacetic acid strongly inhibited conidial germination and hyphal growth of M grisea and C. orbiculare. Phenylacetic acid showed significantly high levels of inhibitory' effect against rice blast and cucumber anthracnose diseases at 250 $\mug$ $ml^{-1}$. The control efficacies of phenylacetic acid against the two diseases were similar to those of commercial compounds tricyclazole, iprobenfos and chlorothalonil .n the greenhouse.

• The Plant Pathology Journal
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• 제22권4호
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• pp.323-328
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• 2006

Serratia marcescens W1, isolated from cucumber-cultivated soil in Suwon, Korea, evidenced profound antifungal activity and produced the extracellular hydrolytic enzymes, chitinase and protease. In order to isolate the antifungal genes from S. marcescens W1, a cosmid genomic library was constructed and expressed in Escherichia coli. Transformants exhibiting chitinase and protease expression were selected, as well as those transformants evidencing antifungal effects against the rice blast fungus, Magnaporthe grisea, and the cucumber leaf spot fungus, Cercospora citrullina. Cosmid clones expressing chitinase or protease exerted no inhibitory effects against the growth of fungal pathogens. However, two cosmid clones evidencing profound antifungal activities were selected for further characterization. An 8.2 kb HindIII fragment from these clones conditioned the expression of antagonistic activity, and harbored seven predicted complete open reading frames(ORFs) and two incomplete ORFs. The deduced amino acid sequences indicated that six ORFs were highly homologous with genes from S. marcescens generating pyrroloquinoline quinone(PQQ). Only subclones harboring the full set of pqq genes were shown to solubilize insoluble phosphate and inhibit fungal pathogen growth. The results of this study indicate that the functional expression of the pqq genes of S. marcescens W1 in E. coli may be involved in antifungal activity, via as-yet unknown mechanisms.

• 농약과학회지
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• 제10권2호
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• pp.69-75
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• 2006

신농약 살균제 개발을 목표로 벼도열병균에 대한 살균활성이 있는 3-메틸-2-페닐이미노-1,3-티아졸린 유도체 1의 분자수정을 통하여 3-아미노-2-페닐이미노-1,3-티아졸린 유도체 2를 isostere의 개념을 근거 하에서 디자인하였다. 화합물 2는 모두 Lipinski 법칙에 따랐으며 가상계산에 의하면 물에 대한 용해도가 화합물 1보다 높았다. 티오우레아 4를 $\gamma$-클로로아세토아세트아닐라이드 유도체 5와 반응시켜 중간체 6H-[1,3,4] 티아디아진 8을 통하여 3-아미노-2-페닐이미노-1,3-티아졸린 유도체 2(195종)의 집중 라이브러리를 구축하였다.