• 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.

• Microbiology and Biotechnology Letters
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• v.10 no.1
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• pp.39-43
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• 1982

t-Cinnamamide has been isolated from the culture filtrate of the isolates, Streptomyces. sp. No.297 The identity of the compound was established by UV and IR spectra, NMR, mass spectra and by chemical reactions. Through antimicrobial activity test using a two-fold serial agar dilution mothjod, t-cinnamamide showed strong growth inhibitory activity against Pellicularia sasakii, Pyriculario oryzae and some pathogenic fungi, but not inhibitory over procaryotes tested.

• Applied Biological Chemistry
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• v.50 no.1
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• pp.18-22
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• 2007

The optimum production condition for the antibiotic from Bacillus thuringiensis BK4 was determined, and the suppression rate of Fusarium-wilt by the butanol-extracted antibiotic was verified by employing tomatoes in vitro and in vivo pot tests. Cell growth and antifungal activity were the best when 0.5% xylose and 0.2% peptone No.3 were given as carbon and nitrogen sources, respectively, in the presence of 5mM $CaCl_2$. The partially purified antibiotic successfully prevented Fusarium oxysporum pathogen in pot experiments. When the pots were treated with both live cells and the partially purified antibiotic, an additive-effect was seen in the suppression of Fusarium-wilt, but synergistic effect was not detected. The antibiotic, denoted BK4, purified by Sephadex LH-20 column chromatography was eluted with a single peak at a retention time of 38 min. on prep-HPLC; Minimum inhibition concentration of the homogenous antibiotic was determined to be 50${\mu}$g/ml.

• Microbiology and Biotechnology Letters
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• v.10 no.3
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• pp.211-215
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• 1982

Streptomyces griseorubiginosus var. soyoensis previously identified, produced two kinds of antifungal antibiotics, trans-cinnamamide and another new substance. The latter was identified to be a new substance of tetraene family by establishment of UV, IR, NMR, mass spectra and chemical reactions and rotatively named as Tetraene KM-A. Through an antimicrobial activity test using serial agar dilution method, Tetraene KM-A showed strong growth inhibitory activity against fungi and yeasts, but not against procaryotes tested. The inhibitory action of Tetraene KM-A on fungi was remarkably ineffective when some of sterols were added to the cultural media. $LD_{50}$ of the Tetrene KM-A to mice and rats by intravenous injection were 84.3 and 90.4 mg/kg respectively. $LD_{50}$ to mice by oral feeding was 1503mg/kg.

• Microbiology and Biotechnology Letters
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• v.29 no.3
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• pp.186-193
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• 2001

A powerful antagonistic bacterium against Phytophthora capsici causing phytophthora blight of red pepper was isolated from the cultivated soil in Kyongju Korea, The bilogical control mechanisms of the isolated strain were caused by strong antifungal antibiotic, siderophore and cellulase. The strain was identified as Chryseomonas luteola by the cultural morphological and physiological characteristics. The opti- mal culture medium for the antibiotic production was determined as follows : 0.15%D(+) cellobiose, 0.55% $NH_4$CI, 0.01% KCI 0.7% $K_2$$HPO_4$ 0.2% $KH_2$PO$_4$ and 0.5% sodium citrate at pH 7.0 The optimal incubation time was 84 hours at $30^{\circ}C$ In pot bioassay, the treatment of C luteola 5042 protected red pepper plant against the blight of Phytophthora capsici.

• Microbiology and Biotechnology Letters
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• v.10 no.1
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• pp.33-37
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• 1982

The work has been carried out for the development of antifungal antibiotics possessing curative effect in the control of sheath blight disease of rice plant. Soil samples were collected from over 1600 spots throughout the country. More than 1300 specimens which seem to be the genus Streptomyces were isolated from the soil samples. Screening procedures consist of respective processes by four steps. Those are growth inhibition test in liquid culture, paper disk method, dendroid test and green house test. 102 isolates appeared to be active against Pellicularia sasakii when all specimens isolated were examined by the first growth inhibition test. Finally a strain of Streptomyces forming strong antifungal substances against P. sasakii was selected from a soil sample of Mt. Soyo, Kyeongi Province. Antifungal substances formed by the strain were isolated and purified from the culture broth and examined for antimicrobial activities as to be specific against fungi but not active on bacterial growth.

• Applied Biological Chemistry
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• v.41 no.3
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• pp.208-212
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• 1998

In order to develop an effective antifungal antibiotics, over 700 isolates of bacteria, mold and actinomytes were screened from soil, and LAM 97-44 were selected as a strain producing the strong antifungal antibiotics against Candida albicans. Morphological, cultural and physiological characteristics of LAM 97-44 were investigated for the indentification. The cell size of LAM 97-44 was $2{\sim}3{\times}1{\sim}1.5\;{\mu}m$, and the shape of spore was of ellipsoidal. As a carbon source, LAM 97-44 utilized fructose, glucose, glycerol, maltose and raffinose but did not utilize arabinose, cellulose and xylose. The fatty acids of the cells included various iso-type and anteiso-type. Conclusively, the strain LAM 97-44 was proved to be Bacillus subtilis.

• Applied Biological Chemistry
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• v.46 no.2
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• pp.69-73
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• 2003

A novel antifungal antibiotic for azole-resistant Candida albicans was purified from the culture broth of Bacillus subtilis LAM 97-44 by butanol extraction, Diaion HP-20 and Dowex-50 adsorption chromatography, silica gel flash chromatography followed by HPLC and designated LAM-44A. LAM-44A was stable for 60 min at $100^{\circ}C$, and pH range from 2 to 10. MIC values were observed at $0.5-3.5\;{\mu}g/ml$ against various Candida albicans strains. The antibiotic showed no cytotoxicity for S180, MKN-45, P388, HeLa and 373 at the concentration of 1 mg/ml. LAM-f4A was colorless powder soluble in water, methanol, ethanol, butanol and negative to ninhydrin reaction. The antibiotic had maximum absorption at 273 nm in methanol, and melting point was $202^{\circ}C$. The molecular weight and formula were determined to be 282 and $C_{14}H_{34}O_5$ by $^1H-NMR,\;^{13}C-NMR$, IR spectrum and elemental analysis.

• Microbiology and Biotechnology Letters
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• v.31 no.3
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• pp.235-241
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• 2003

For the biological control of Phytophthora blight of red-pepper caused by Phytophthora capsici, an antibiotic-producing plant growth promoting rhizobacteria (PGPR) Bacillus sp. KL 39 was selected from a local soil of Kyongbuk, Korea. The strain KL 39 was identified as Bacillus megaterium by various cultural, biochemical test and API and Microlog system. B. megaterium KL 39 could produce the highest antifungal antibiotic after 40 h of incubation under the optimal medium which was 0.4% fructose, 0.3% yeast extract, and 5 mM KCl at 30 C with initial pH 8.0. The antifungal antibiotic KL 39 was purified by Diaion HP-20 column, silica gel column, Sephadex LH-20 column, and HPLC. Its RF value was confirmed 0.32 by thin-layer chromatography with Ethanol:Ammonia:Water = 8:1:1. The crude antibiotic KL39 was active against a broad range of plant pathogenic fungi, Rhizoctonia solani, Pyricularia oryzae, Monilinia fructicola, Botrytis cinenea, Alteranria kikuchiana, Fusarium oxysporum and Fusarium solani. The purified antifungal antibiotic KL39 had a powerful biocontrol activity against red-pepper phytophthora blight disease with in vivo pot test as well as the strain B. megaterium KL 39.

• Microbiology and Biotechnology Letters
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• v.30 no.1
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• pp.21-25
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• 2002

Structural analysis was performed by the $^1$H-NMR, $^{13}$ C-NMR, amino acid composition analysis and FAB-mass. The instrumental analysis represented that the potential antifungal antibiotic belonged to the iturin E group antibiotic, consisting of 7 $\alpha$-amino acid residues and a collection of $\beta$-amino acid with aliphatic side chain. Compared to the Iturin E group, notably, the potent antifungal antibiotic from Bacillus sp. YJ-63 carried longer $\beta$-amino acid side chain. In conclusion, these findings identified a potential antibiotic, which contained a stable cyclopeptide structure with long $\beta$-amino acid side chain.