• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.393-400
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• 2016

Fusarium graminearum is the main cause of substantial economic loss in wheat production. The aim of this study is to investigate biocontrol potential of Lysobacter antibioticus HS124 against F. graminearum and to purify an antifungal compound. In preliminary study, n-butanol crude extract revealed destructive alterations in the hyphal morphology of F. graminearum and almost degraded with $1,000{\mu}g\;mL^{-1}$ concentration. For further study, the antifungal compound extracted from the n-butanol crude extract of L. antibioticus HS124 was identified as N-Butyl-tetrahydro-5-oxofuran-2-carboxamide ($C_9H_{16}NO_3$) using NMR ($^1H-NMR$, $^{13}C-NMR$, $^1H-^1H\;COSY$, HMBC, and HMQC), and HR-ESI-MS analysis. To our knowledge, N-Butyl-tetrahydro-5-oxofuran-2-carboxamide may be a novel compound with molecular weight of 186.1130. The minimum inhibitory concentration value of antifungal compound was $62.5{\mu}g\;mL^{-1}$ against F. graminearum. In an in vivo pot experiment, crown rot disease from F. graminearum was inhibited when wheat seeds were treated with both HS124 culture and F. graminearum. Growth of wheat seedling was enhanced by treatment of HS124 compared to control. Our results suggest that L. antibioticus HS124 characterized in this study could be successfully used to control F. graminearum and could be used as an alternative to chemical fungicides in modern agriculture.

• 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.

• Journal of the Korean Magnetic Resonance Society
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• v.18 no.2
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• pp.82-88
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• 2014

Three bicyclic and one monocyclic sesquiterpenoids were isolated from the marine sponge Topsentia species. Their planar structures were completely determined from a combination of extensive 1D and 2D NMR experiments, and also the relative stereochemistry on the chiral centers were established by the ROESY experiment. Compound 1 was determined as a new stereoisomer. Furthermore, the NMR spectral data for compounds 2 and 4, of which have not been reported, were listed. Four compounds did not show any cytotoxicity, instead compound 4 exhibited moderate antifungal activity against Candida albicans.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.2
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• pp.467-470
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• 2006

Bioactivity directed isolation has led to the isolation of (-)-ent-costunolide (1) as the major active compound. This compound (1) inhibited the growth of the dermatophytic fungus Trichophyton mentagrophytes ATCC 28185, (4 mm inhibition zone at $15\;{\mu}g/disc$).

• Journal of Life Science
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• v.14 no.1
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• pp.193-197
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• 2004

A continuous enrichment culture procedure was used to isolate bacteria from various soil sources capable of suppressing large patch disease of turfgrass. Six isolates consistently suppressed large patch in turfgrass, and ranged in the spectrum of extracellular enzymes that they expressed. The best disease- suppressing isolate, TBM912, expressed protease, CMCase, and pectinase activity and inhibited the growth of Rhizectonin solani and Betrytis cinerea in vitro. Here we show that this strain also produces an antibiotic that was identified by TLC, SDS-PACE and HPLC analysis as lipopeptide.

• 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.

• The Plant Pathology Journal
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• v.28 no.1
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• pp.93-100
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• 2012

The rhizobacterium NJ134, showing strong $in$ $vitro$ antifungal activity against $Fusarium$ $oxysporum$, was isolated from field grown tomato plants and identified as $Pseudomonas$ sp. based on 16S ribosomal DNA sequence and biochemical analyses. The antifungal compound purified by gas chromatography-mass spectrometry, infrared, and nuclear magnetic resonance analyses from NJ134 cultures was polyketide 2,4-diacetylphloroglucinol (DAPG). Analysis of the sequence of part of one of the genes associated with DAPG synthesis, $phlD$, indicated that the DAPG producer NJ134 was a novel genotype or variant of existing genotype termed O that have been categorized based on isolates from Europe and North America. A greenhouse study indicated that about $10^8$ CFU/g of soil NJ134 culture application was required for effective biocontrol of Fusarium wilt in tomato. These results suggest that a new variant genotype of a DAPG-producing strain of $Pseudomonas$ has the potential to control Fusarium wilt under the low disease pressure conditions.

• Applied Biological Chemistry
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• v.42 no.4
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• pp.271-276
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• 1999

Several Streptomyces strains were tested for potent antifungal agents active against phytopathogenic fungi. Among the tested, S. hygroscopicus MJM1004 showed a potent antifungal activity when assayed using Candida albicans as indicator organism. With the strain of MJM1004, fermentation medium for the production of an antifungal agent was developed with varying carbon sources, nitrogen sources, and mineral elements, which resulted in the highest productivity in the medium containing 2% soybean meal, 1% glucose, 2% starch, 0.3% $CaCO_3$, 0.05% $MgSO_4{\cdot}7H_2O$, 0.05% $K_2HPO_4$. The active compound showed a broad spectrum of antifungal activity against several plant pathogenic fungi. The antifungal compound was purified and showed the physicochemical characteristics similar to azalomycin F complex in NMR and MS analysis.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.268-270
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• 2003

Methanol extract obtained from aerial parts of Platycarya strobilacea was successively fractionated with n-hexane, ethylacetate, n-butanol, and water. From ethylacetate fraction, an active compound was isolated through repeated silica gel column chromatography and was identified as 5-hydroxy-2-methoxy-1,4-naphthoquinone by MS and NMR analyses. The compound showed in vivo 76% antifungal activity at $100\;{\mu}g/ml$ against tomato late blight disease.

• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1217-1220
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• 2007

The saprophytic fungus Ulocladium atrum Preuss is a promising biological control agent for Botrytis cinerea in greenhouse- and field-grown crops. However, despite its known potent antifungal activity, no antifungal substance has yet been reported. In an effort to characterize the antifungal substance from U. atrum, we isolated an antibiotic peptide. Based on extensive spectroscopic analyses, its structure was established as a cyclopeptolide with a high portion of N-methylated amino acids, and its $^1H$ and $^{13}C$ chemical shifts were completely assigned based on extensive 1D and 2D NMR experiments. Compound 1 exhibited potent antifungal activity against the plant pathogenic fungus Botrytis cinerea and moderate activity against Alternaria alternate and Magnaporthe grisea.