• KSBB Journal
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• 제15권6호
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• pp.584-588
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• 2000

The optimum conditions for the production of an antifungal antibiotic from Bacillus sp. YJ-63 were investigated. The oprimumized medium consisted of 1.5% soluble starch, 1% tryptone and 0.5% yeast extract, and temperature and initial medium pH for production were optimal at 35$^{\circ}C$ and pH 6.0, respectively. Production yield was significantly improved by shaking culture using 50 ml medium in 500 ml flasks. Under these conditions, the production of the antifungal antibiotic was growth-dependent, from 35hrs into cultivation to the stationary phase and endospore formation.

• Journal of Applied Biological Chemistry
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• 제57권2호
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• pp.159-160
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• 2014

An antifungal antibiotic was extracted three times using n-butanol from the culture broth of Bacillus sp. Bioassayguided column chromatography with silica gel and Sephadex LH-20 yielded 62 mg of the original active compound from 1 L of culture broth. The minimal inhibitory concentration values were 25 and $50{\mu}g/ml$ against Pyricularia oryzae and Pellicularia filamentosa, respectively. Based on results obtained from the analysis of the structure of the antibiotic using MS, NMR, and IR spectroscopy, the antifungal antibiotic was shown to consist of only six of fructose.

• 한국미생물·생명공학회지
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• 제30권1호
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• pp.21-25
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• 2002

토양으로부터 분리한 Bacillus sp. YJ-63으로부터 항진균성 항생물질을 분리하여 그 구조를 분석한 결과는 다음과 같다. 항생물질은 7개의 $\alpha$-amino acid와 1개의 $\beta$-amino acid가 결합한 환상구조를 가지는 iturin E 계에 속하며 특히. $\beta$-amino acid의 methylene 수가 기존의 iturin E 보다 더 많은 것으로 나타났다.

• 한국미생물·생명공학회지
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• 제27권3호
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• pp.191-196
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• 1999

A multifunctional antagonistic bacterium, producing both antifungal antibiotic and chitinase that could be used as biocontrol agents against fungal plant pathogens was isolated from the plant-disease suppressive soil. The isolate was identified as Promicromonospora sp. KH-28 from various morphological, biochemical and physiological tests. The antifungal antibiotic produced by Promicromonospora sp. KH-28 was soluble in n-butanol, methanol, toluene, n-hexane, ethanol but insoluble in H2O, acetone, chloroform, ethylacetate and ethylether. It inhibited the growth of fungal plant pathogens of Fusarium solani, F. oxysporum, Alternaria mali and Phytophthora capsici. The antagonistic Promicromonospora sp. KH-28 produced optimally the antifungal antibiotic when it was cultivated at pH 7, 3$0^{\circ}C$ for 5 days.

• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.1001-1010
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• 2005

Bacillus megaterium KL39, an antibiotic-producing plant growth promoting rhizobacterium (PGPR), was selected from soil. The antifungal antibiotic, denoted KL39, was purified from culture filtrate by column chromatography using Dion HP-20, Silica gel, Sephadex LH-20, and prep-HPLC. Thin layer chromatography, employing the solvent system of ethanol:ammonia:water=8:1:1, showed the $R_{f}$. value of 0.32. The antibiotic KL39 showed a negative reaction with ninhydrin solution, positive with iodine vapor, and also positive with Ehrlich reagent. It was soluble in methanol, ethanol, butanol, and acetonitrile, but insoluble in chloroform, toluene, hexane, ethyl ether, or acetone. Its UV spectrum had the maximum absorption at 208 nm. Amino acid composition, FAB-mass, $^{1}H-NMR,\;^{13}C-NMR$, and atomic analyses showed that the antibiotic KL39 (MW=1,071) has a structure very similar to iturin E. The antibiotic KL39 has a broad antifungal spectrum against a variety of plant pathogenic fungi including Rhizoctonia solani, Pyricularia oryzae, Monilinia froeticola, Botrytis cinenea, Altenaria kikuchiana, Fusarium oxysporum, and F. solani. An MIC value of $10\;{\mu}g/ml$ was determined for Phytophthora capsici. Macromolecular incorporation studies with P. capsici using radioactive [$^{3}H-adenine$] as the precursor, indicated that the antibiotic KL39 strongly inhibits the DNA biosynthesis of the fungal cell. Microscopic observation of the antifungal action showed abnormal hyphal swelling of P. capsici. The purified antibiotic KL39 was very effective for the biocontrol of in vivo Phytophthora-blight disease of pepper.

• 한국식물병리학회지
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• 제14권3호
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• pp.191-202
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• 1998

About 300 actinomycetes were isolated from two forest and one sea-shore soil and tested for inhibitory effects on mycelial growth of six plant pathogenic fungi Magnaporthe grisea, Alternaria mali, Colletotrichum gloeosporioides, Phytophthora capsici, Fusarium oxysporum f. sp. cucumerinum, and Rhizoctonia solani. Among 300 actinomycetes tested, only 16 actinomycetes showed the antifungal activity against the test fungi. Isolate NH 50 was selected for production and purification of antifungal antibiotic substances. Actinomycete isolate NH 50 displayed the broad antifungal spectra against 11 plant pathogenic fungi. To identify actinomycete isolate NH 50, cultural characteristics on various agar media, diaminopimelic acid type, and morphological characteristics by scanning electron microscopy were examined. As a result, actinomycete isolate NH 50 was classified as a rare actinomycete that had LL-DAP type and did not produce spores. After incubation of isolate NH 50 in yeast extract-malt extract-dextrose broth, antifungal compound NH-B1 that inhibited mycelial growth of some plant pathogenic fungi was purified from the methanol eluates of XAD-16 resins by a series of purification procedures, i.e., silica gel flash chromatography, C18 flash chromatography, Sephadex LH-20 column chromatography, silica gel medium pressure liquid chromatography (MPLC), C18 MPLC, and high pressure liquid chromatography (HPLC). UV spectrum and 1HNMR spectrum of antifungal compound NH-B1 dissolved in methanol were examined. The antibiotic NH-B1 showed the major peaks at 230 and 271.2nm. Based on the data of 1H-NMR spectrum, NH-B1 was confirmed to be an extremely complex polymer of sugars called polysaccharides. The antibiotic NH-B1 showed strong antifungal activity against Alternaria solani and Cercospora kikuchi, but weak activity against M. grisea.

• Journal of Microbiology and Biotechnology
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• 제9권5호
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• pp.672-674
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• 1999

Cepacidine A was first identified as a novel antifungal antibiotic which was isolated from the culture broth of Pseudomonas cepacia AF200l. It showed a potent in vitro antifungal activity against various pathogenic fungi, but did not show any activity against bacteria. Recently, the immunosuppressive action of cepacidine A was discovered using an in vitro screening system involving inhibition of the proliferation of murine lymphocytes stimulated by 2 mitogens, and also by in vivo mouse models involving inhibition of delayed type hypersensitivity and SRBC hemagglutination. Cepacidine A showed a significant activity of cellular immunosuppression (ED/sub 50/) at concentration levels of 1-3 ㎎/㎏, i.p.. Unfortunately, the delayed toxicity at a dose of above 3 ㎎/㎏ i.p. was apparent.

• Journal of Microbiology and Biotechnology
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• 제9권3호
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• pp.276-281
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• 1999

In order to determine the functional region of the antifungal protein (AFP) isolated from Aspergillus giganteus responsible for growth inhibitory activity and the promotion of phospholipid vesicle aggregation, overlapping peptides covering the complete sequence of AFP were synthesized. The antibiotic activity against bacterial, fungal, and tumor cells, and the vesicle-aggregation activity of the synthetic peptides were investigated. The AFP functional sequence responsible for antibiotic and vesicle-aggregation activity was determined to be located within the region between AFP residues 19 to 32. AFP (19-32) exhibited an a-helical conformation in a cell membrane-like environment. AFP (19-32) displayed potent antibiotic activity against bacterial, fungal, and tumor cells without peptide toxicity as indicated by hemolysis. Accordingly, AFP (19-32) could be used as a good model for the design of effective antibiotic agents with powerful antibiotic activity yet without any cytotoxic effects against the host organism.

• 한국미생물·생명공학회지
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• 제27권5호
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• pp.349-353
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• 1999

Antagonistic Promicromonospora sp. KH-28 isolated from a suppressive soil could produced a chitinase and a antifungal antibiotic for the biocontrol ability. The chitinase and the antibiotic appeared to inhibit plant pathogens of Fusarium oxysporum. Phytophthora capsici, Alternaria kiki, fusarium solani, Stemphylium sp., and Psudomonas fluorescens. the antibiotic produced from the strain was identified as a antifungal substance of 503 dalton having a pyrimidine skeleton with an aliphatic side chain. The Promicromonospora sp. KH-28 was able to suppress effectively F. oxysporum derived-fusarium wilt of red-pepper plant in the pot in vivo test.

• 한국미생물·생명공학회지
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• 제32권4호
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• pp.312-316
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• 2004

토양 우점능이 강한 생물학적 방제제 제조를 위해 경북지역 토양에서 길항균주를 분리하고 이들 중 Fusarium oxysporum, Phytophthora capsici 에 강력한 길항능을 보이는 Pseudomonas sp. 4059 를 선발, 동정하였다. Pseudomonas sp. 4059 의 시들음 병균 Fusarium oxysporum, 고추 역병균 Phytophthora capsici 에 대한 길항기작은 내열성 저분자의 항생물질과 철이온을 특이적으로 흡착하는 siderophore의 생산에 의한 것이다. Pseudomonas sp. 4059 는 항진균성 항생물질 Phenazine 생산 유전자를 소유하며 Salkowski test에 양성인 옥신류 생산도 한다는 것을 확인하였다. Pseudomonas sp. 4059 는 bioochemical tests, API test, MicroLogTM system을 통해 Pseudomonas fluorescens (biotype A)으로 98% 상동성을 보였으므로 이를 Pseudomonas fluorescens (biotype A) 4059 로 명명하였다. 선발된 길항균 Pseudomonas fluorescens (biotype A) 4059는 고추를 기주식물로 하였을 때 고추역병균인 Phytophthora capsici가 원인이 되는 고추역병을 in vivo 상에서도 충분히 억제할 수 있는 생물방제능을 나타내었다.