• KSBB Journal
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• v.15 no.6
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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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• v.57 no.2
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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.

• 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.

• Microbiology and Biotechnology Letters
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• v.27 no.3
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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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• v.15 no.5
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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.

• Korean Journal Plant Pathology
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• v.14 no.3
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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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• v.9 no.5
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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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• v.9 no.3
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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.

• Microbiology and Biotechnology Letters
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• v.27 no.5
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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.

• Microbiology and Biotechnology Letters
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• v.32 no.4
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• pp.312-316
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• 2004

In oder to select the powerful rhizophere-dorminatable biocontrol agent, we had isolated an indigenous antagonistic bacterium which produced antibiotic and siderophore from a disease suppressive local field soil of Gyungsan, Korea. And we could select the Pseudomosp. 4059 which can strongly antagonize against Fusarium oxysporum and Phytophthora capsici by two kinds of antifungal mechanism that can be caused by the antibiotic of Phenazin, a siderophore and a auxin like subThe selected strain was identified as Pseudomonas fluorescens (biotype A) 4059 by biochemical tests, API $\textregistered$ test, MicroLog TM system and 16S rDNA analysis. The selected antagonistic microorganism, Pseudomosp. 4059 had an antifungal mechanism of antifungal antibiotic and sidrophore. And we were confirmed the antagonistic activity of P fluorescens 4059 with in vitro antifungal test against Phytophthora capsici and in vivo by red-pepper.