• Microbiology and Biotechnology Letters
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• v.39 no.2
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• pp.168-174
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• 2011

In order to develop safe and economic novel antifungal agents, we prepared 73 methanol extracts from medicinal and edible herbs and examined their 365 solvent fractions using n-hexane, methylene chloride, ethylacetate, butanol and water residue based on the sequential organic solvent fraction method. When using the various fractions in the screening step for antifungal activity, we discovered ethylacetate fraction of Morus alba L., methylene chloride fraction of Pimpinella brachycarpa (MCPB), and n-hexane fraction of Salvia miltiorrhiza Bunge, which all have activities in methanol extracts, as potential sources of antifungal agents. Amongst these, the antifungal activity of P. brachycarpa has not to date been reported on. In addition, the mycelial growth inhibition and spore germination inhibition activities of MCPB against A. niger were confirmed by disc-diffusion assay in a 10 day culture. The MIC and MFC of MCPB were determined as 0.25 and 0.5 mg/ml, respectively. The MCPB has no hemolytic activity against human RBC at 0.5 mg/ml and glycoside-flavonoids are theorized to be active constituents. These results suggest that MCPB has a prominent antifungal activity and that the application of sequential organic solvent fractions, instead of simple natural product extracts, is useful in the screening process of novel bioactive substances.

• Microbiology and Biotechnology Letters
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• v.46 no.1
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• pp.68-76
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• 2018

Actinobacterial strains isolated from Cow feces were studied for their antifungal attributes against phytopathogens and industrially important enzymes. A total of 30 Actinobacterial strains were obtained from 10 samples of cow feces. All the strains were belonging to the genera Streptomyces on the basis of morphological and chemotaxonomic analysis. During preliminary screening, out of 30 strains, 15 strains (50%) showed antifungal activity against five fungal phytopathogens including Aspergillus niger, Fusarium solani, Fusarium oxysporum, Macrophomina phaseolina and Rhizoctonia solani. While, isolate GBTCF-26 was found to be most active against R. solani with 62.2% inhibition of fungal mycelium, GBTCF-09 was prominent against F. solani and F. oxysporum with percent inhibition of 61.1% and 58.8%, respectively. Out of 30 strains, 19 (63.3%), 16 (53.3%), 11 (36.7%), 10 (33.3%), 4 (13.3%) and 8 (26.7%) strains were producing amylase, caseinase, gelatinase, lipase, chitinase and cellulose, respectively. The selected strains, GBTCF-09, GBTCF-21 and GBTCF-26, were identified as Streptomyces sp. on the basis of their 16S rDNA sequence. The study supports the idea that the Actinobacteria from unique niches (Cow feces) possess the production potential of industrially important enzymes including bioactive molecules.

• Microbiology and Biotechnology Letters
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• v.24 no.5
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• pp.574-578
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• 1996

In the course of screening for the antifungal compounds against Candida albicans, an antifungal compound (F1480) was isolated from the culture broth of Aspergillus candidus F1484. Isolation and purification of compound F1484 were performed using ethyl acetate extraction, silica gel column chromatography, ODS column chromatography, and preparative HPLC. The structure of compound F1484 was determined by the spectroscopic analyses of EI-MS, $^{13}$C, $^{1}$H-NMR, DEPT, HMQC, and HMBC. This compound appeared to have a structure of antifungal agent, chloroflavonin. In addition to antifungal activities against the yeast phase of Candida species, compound F1484 showed cytotoxic effect against various human tumor cell lines.

• Journal of Microbiology and Biotechnology
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• v.24 no.3
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• pp.354-358
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• 2014

A screening test showed that lycorine exhibited significant antifungal activity against 24 pathogenic crop fungi at concentrations of 500 ${\mu}g/ml$ and 100 ${\mu}g/ml$, respectively. Fusarium graminearum was selected for antifungal mechanism studies by observing its mycelial morphology and investigating the variations in its conductivity. In addition, the substance absorption and metabolism of F. graminearum were explored. The mechanism was revealed as being one by which lycorine destroyed the cellular membrane and further influenced substance absorption and cell metabolism.

• Microbiology and Biotechnology Letters
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• v.21 no.4
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• pp.322-328
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• 1993

During the screening of antifungal compounds from microbial secondary metabolites to control phytophthora blight of red pepper caused by Phytophthora capsici, a soil isolate, strain 38D10 was selected. Based on taxonomic studies, this strain was identified as Streptomyces neyagawaensis. The antifungal compound was purified from culture broth by HP-20 column chromatography, ethyl acetate extraction, silica gel column chromatography, HPLC and identified as concanamycin B by UV. $^1H$-NMR, $^{13}C$-NMR, SIMS analysis. Concanamycin B has strong antifungal activity against some phytopathogenic fungi but not antivacterial activity and preventive value were 50% and 100% at 125ppm and 250ppm in pot assay.

• Mycobiology
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• v.48 no.6
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• pp.484-494
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• 2020

Oak wilt disease caused by Raffaelea quercus-mongolicae has emerged obviously in Korea. We selected antifungal isolates against R. quercus-mongolicae among 368 endophytic fungal isolates from different parts of oak and pine trees. The experiment was conducted in the primary and secondary screenings by dual culture test. The antifungal activity of the selected isolates was assessed in culture filtrate test based on the inhibition rates in mycelial growth, sporulation, and spore germination of oak wilt fungus. Five isolates, E089, E199, E282, E409 and E415, showed strong antifungal activity in culture filtrate test, and their antifungal activity decreased on the culture media supplemented with heated culture filtrate. Higher mycelial growth inhibitions on the unheated media were recorded in E409 (Colletotrichum acutatum), E089 (Daldinia childiae), E415 (Alternaria alternata) and E199 (Daldinia childiae) with the inhibition rates of 79.0%, 70.1%, 68.9% and 64.5%, respectively. These isolates also had the higher sporulation inhibitions on unheated media with the rates of 96.8%, 84.2%, 82.8% and 80.5%, respectively. The spore germination of the oak wilt fungus was completely inhibited by E282 (Nectria balsamea) on both unheated and heated media. These results showed that a higher number of potent antifungal isolates against oak wilt fungus was isolated from the petiole compared to the other parts. This study could contribute to the development of biological control approaches for the management of oak wilt disease caused by R. quercus-mongolicae.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.19-26
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• 2000

In order to select potent bioactive isolates, 70 Fusarium isolates obtained from soil and 21 plant species were screened by antifungal, insecticidal, herbicidal, and duckweed bioassays after culturing in potato dextrose broth and rice solid media. Eight (11.4%) of the 70 liquid broth cultures showed disease-controlling activities more than 80% against at least one of the 6 plant diseases tested. Fusarium sp. FO-68 isolate exhibited the most potent antifungal activity; it controlled rice blast, wheat leaf rust, and barley powdery mildew with control values more than 95%. Out of 70 solid cultures, 21 (30.0%) controlled at least one plant disease more than 80% and F. equiseti FO-68 isolate showed disease-controlling activities more than 95% against 3 plant diseases such as rice blast, tomato late blight, and wheat leaf rust. As for tile insecticidal activities, 2 liquid and 1 solid cultures showed potent insecticidal activities against pest insects more than 80%, Liquid cultures of F. oxysporum FO-61 and Fusarium sp. FO-80 isolates exhibited insecticidal activities more than 80% against green peach aphid and diamondback moth, respectively. The solid culture of Fusarium sp. FO-510 isolate had 80% insecticidal activity against green peach aphid. However, none of liquid and solid cultures of the 70 Fusarium isolates showed potent herbicidal activities against 10 upland weeds. As the results of duckweed assay, 3 liquid cultures showed 70% growth inhibitory activity at concentrations less than 1.25% of culture supernatants and 9 solid cultures had a potent inhibitory activity against duckweed growth. On the other hand, there was a significant correlation between antifungal activities and herbicidal activities against duckweed of both liquid and solid cultures of tile 70 Fusarium isolates.

• Applied Biological Chemistry
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• v.41 no.6
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• pp.471-476
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• 1998

A synthesis and the screening of new 2-iminothiazolines (IV) of which structures are modified based on a lead compound, thiazoline for development of new agrochemical fungicide were described. Bromination of acetoacetanilides (I) which were prepared by the reaction of diketene with anilines gave the corresponding ${\gamma}-bromoacetoactanilide\;(II)$. Treatment of II with N-phenyl-N'-methyl thiourea (III) afforded IV, structure of which was confirmed by various spectroscopic methods. Antifungal activity of the new IV was tested against six kinds of typical plant diseases (in vivo). The IV with aromatic substituents showed remarkable activity against the Pyricuraria oryzae at 250 ppm in primary screening. The candidates with control value over 90% in primary screening were selected and further tested for second screening at lower concentrations. The IV which has an electron-withdrawing substituent such as halogen, especially fluorine in aryl group showed a higher activity as compared to those with electron-donating group and meta substituent was for optimal position.

• Asian Journal of Turfgrass Science
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• v.12 no.3
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• pp.183-194
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• 1998

Of crude extracts from 30 species belonging to the 21 families of medical plants, the crude extracts from Cinnamomum cassia, Paeonia moutan, Dictamnus dasycarpus showed highly antifungal activities against Rhizoctonia solani AG1-1 and R. solani AG2-2. The antifungal activity of C. cassia and P. moutan against R. solani AG1-1 were the highest through 100% methanol extraction, but the one of D. dasycarpus were the highest through 80% methanol extraction. On the other hand, against R. solani AG2-2 the antifungal activity of them were the highest through 100% methanol. C. cassia P. mouton and D. dasycarpus showed over 60% inhibition of mycelial growth against R. solani AG1-1 and R. solani AG2-2 on up to 500 fold dilution. The crude extract of P. moutan showed broader antifungal spectrum compared with those of C. cassia and D. dasycarpus. The crude extract of C. cassia was not phytotoxic at over 250 fold dilution and the crude extract of P. moutan was not phytotoxic at over 100 fold dilution. The crude extract of D. dasycarpus was not phytotoxic even at full concentration. The control values of P. moutan and D. dasycarpus were increased 75.0% and 79.1% respectively 30 days after treatment.

• Journal of Microbiology and Biotechnology
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• v.10 no.4
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• pp.435-440
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• 2000

A pathogenic fungus causing balloon flower root rot (Platycodon grandiflorum) was isolated from naturally infected roots. The microbial characteristics of the isolated microorganism were similar to those of Rhizoctonia solani. About 500 bacterial species from field soils were screened for a biological agent against the above-mentioned putative pathogen, and several bacteria with the antifungal activity were isolated. Among them, the isolated JS2 was identified as Pseudomonas aeruginosa. This strain showed a broad spectrum of antifungal activity potentially. When the antifungal substance was purified from a broth culture of JS2, it was identified as 2,4-diacetylphloroglucinol (Phl).