• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3675-3681
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• 2011

Fusarium oxysporum, an important pathogen that mainly causes vascular or fusarium wilt disease which leads to economic loss. Disruption of gene encoding a heterotrimeric G-protein-${\beta}$-subunit (FGB1), led to decreased intracellular cAMP levels, reduced pathogenicity, colony morphology, and germination. The plant defense protein, Nicotiana alata defensin (NaD1) displays potent antifungal activity against a variety of agronomically important filamentous fungi. In this paper, we performed a molecular modeling and docking studies to find vital amino acids which can interact with various antifungal compounds using Discovery Studio v2.5 and GRAMMX, respectively. The docking results from FGB1-NaD1 and FGB1-antifungal complexes, revealed the vital amino acids such as His64, Trp65, Ser194, Leu195, Gln237, Phe238, Val324 and Asn326, and suggested that the anidulafungin is a the good antifungal compound.The predicted interaction can greatly assist in understanding structural insights for studying the pathogen and host-component interactions.

• 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.

• Korean Journal Plant Pathology
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• v.14 no.3
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• pp.203-208
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• 1998

We isolated and characterized an antifungal peptide from the seeds of Phytolacca americana. Growth inhibition assay with Botrytis cinerea was used to screen inhibitory proteins from 60 different plant species. A 4 kDa antifungal peptide (Pa-AFP) inhibitory to hyphal growth of B. cinerea was found in the seeds of P. americana. The peptide Pa-AFP was purified to homogeneity by chromatographies of Sephadex G-50, DEAE-Sepharose, Sephacryl S-300, and C18 reverse-phase HPLC. Western blot analysis showed that a polyclonal antibody raised against the purified peptide cross-reacted with a 4 kDa protein in seeds but not in root and leaf tissues of P. americana. Pa-AFP inhibited the hyphal growth of Botrytis cinerea, Rihzoctonia solani, Fusarium oxysporum, and Magnaporthe grisea. Pa-AFP exhibited growth inhibition of Saccharomyces cerevisiae strain BWG7a, which was sensitive to osmotin.

• Mycobiology
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• v.46 no.2
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• pp.129-137
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• 2018

Black rot disease in orchids is caused by the water mold Phytophthora palmivora. To gain better biocontrol performance, several factors affecting growth and antifungal substance production by Pseudomonas aeruginosa RS1 were verified. These factors include type and pH of media, temperature, and time for antifungal production. The results showed that the best conditions for P. aeruginosa RS1 to produce the active compounds was cultivating the bacteria in Luria-Bertani medium at pH 7.0 for 21 h at $37^{\circ}C$. The culture filtrate was subjected to stepwise ammonium sulfate precipitation. The precipitated proteins from the 40% to 80% fraction showed antifungal activity and were further purified by column chromatography. The eluted proteins from fractions 9-10 and 33-34 had the highest antifungal activity at about 75% and 82% inhibition, respectively. SDS-PAGE revealed that the 9-10 fraction contained mixed proteins with molecular weights of 54 kDa, 32 kDa, and 20 kDa, while the 33-34 fraction contained mixed proteins with molecular weights of 40 kDa, 32 kDa, and 29 kDa. Each band of the proteins was analyzed by LC/MS to identify the protein. The result from Spectrum Modeler indicated that these proteins were closed similarly to three groups of the following proteins; catalase, chitin binding protein, and protease. Morphological study under scanning electron microscopy demonstrated that the partially purified proteins from P. aeruginosa RS1 caused abnormal growth and hypha elongation in P. palmivora. The bacteria and/or these proteins may be useful for controlling black rot disease caused by P. palmivora in orchid orchards.

• Proceedings of the Botanical Society of Korea Conference
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• 1998.07a
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• pp.19-26
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• 1998

• Proceedings of the Zoological Society Korea Conference
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• 1997.10a
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• pp.14-26
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• 1997

No Abstract, See-Full-Text

• Journal of Microbiology and Biotechnology
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• v.16 no.3
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• pp.450-456
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• 2006

Pseudomonas fluorescens MC07 is a growth-promoting rhizobacterium that suppresses mycelial growth in fungi such as Rhizoctonia solani, Pythium ultimum, Fusarium oxysporum, and Phytophthora capsici. To determine the role of the bacterium's antifungal activity in disease suppression, we screened 2,500 colonies generated by Tn5lacZ insertions, and isolated a mutant 157 that had lost antifungal activity. The EcoRI fragment carrying Tn5lacZ was cloned into pBluescript II SK(+) and used as a probe to isolate wild-type clones from a genomic library of the parent strain, MC07. Two overlapping cosmid clones, pEH4 and pEH5, that had hybridized with the mutant clone were isolated. pEH4 conferred antifungal activity to the heterologous host P.fluorescens strain 1855.344, whereas pEH5 did not. Through transposon mutagenesis of pEH4 and complementation analyses, we delineated the 14.7-kb DNA region that is responsible for the biosynthesis of an antifungal compound. DNA sequence analysis of the region identified 11 possible open reading frames (ORF), ORF1 through ORF11. A BLAST search of each putative protein implied that the proteins may be involved in an antifungal activity similar to polyketides.

• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.337-341
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• 2001

To isolate antifungal substances from Korean radish (Raphanus Sativus L.) seeds, various purification techniques such as DE52 cellulose anion exchange, SP-Sephadex C-25 cation exchange, and Sephadex G-50 gel filtration chromatographies were used. The molecular masses of two purified R. sativus antifungal proteins (RAPs) were estimated to be about 6.1 kDa (RAP-1) and 6.2 kDa (RAP-2) by SDS-PAGE, and 5.8 kDa(RAP-1) and 6.2 kDa (RAP-2 by a gel filtration chromatography, respectively. Purified proteins RAP-1 and 2 clearly exhibited different growth inhibitory activities against other microorganisms like Candida albicans and Saccharomyces cerevisiae. Although they have similar molecular masses, both RAP-1 and 2 proteins are not identical because their microbial inhibitory actions were different. Therefore, RAP-1 could be a new antifungal protein when compared with the antifungal activities of 2S albumins, Rs-AFPs, Mj-AMPs, chitinase, glucanase, permatin, and ribosome inactivating proteins, all of which are anifungal proteins of plants.

• YAKHAK HOEJI
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• v.55 no.3
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• pp.227-233
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• 2011

We previously reported the protein isolated from Coptidis Rhizoma (CRP), which has antifungal activity against a fungal pathogen, Candida albicans. In the current study, we investigated what portion in the CRP is responsible for the antifungal activity. For the investigation, the CRP was fractionated on a Shepadex G-50 column. Data resulting from the fractionation, seven fractions were obtained. Fractions (Fr.) I, II, and III eluted initially from the column showed no inhibitory effect on the growth of C. albicans, whereas Fr. IV, V, and VI eluted later revealed inhibition of the growth, and Fr. IV and VI showed potent antifungal activity by broth susceptibility analysis. However, Fr. VI was contained in the CRP more than Fr. IV, which led us to select the VI for the following experiments. In a murine model of a subcutaneous candidiasis caused by C. albicans, the Fr. VI displayed a therapeutic effect on nude mice pretreated with anti-neutrophil monoclonal antibody (RB68C5) and then infected subcutaneously with live C. albicans. At day 16, these mice were healed almost up to 78% of the infected area when compared to infected area of control nude mice that received diluent (Dulbecco's Phosphate-Buffered Saline; DPBS), instead of the Fr. VI (P<0.01). The Fr. VI blocked hyphal formation from blastoconidial form of C. albicans (P<0.01), which might prevent penetration of hyphae to the deeper site of skin and thus helps the healing. In the ionic strength test, the effect of Fr. was influenced by $Ca^{2+}$ ion just like other known antimicrobial peptides, but the influence was affected at an extremely high concentration such as 500 mM. Thus, such ion-concentration is considered to be meaningless in the clinical situation. Considering all data together, Coptidis Rhizoma is appeared to produce an antimicrobial peptide that has therapeutic effect on subcutaneous infection caused by C. albicans.

• Journal of Microbiology and Biotechnology
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• v.22 no.10
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• pp.1359-1366
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• 2012

A strain of Streptomyces cavourensis subsp. cavourensis (coded as SY224) antagonistic to Colletotrichum gloeosporioides infecting pepper plants was isolated. SY224 produced lytic enzymes such as chitinase, ${\beta}$-1,3-glucanase, lipase, and protease in respective assays. To examine for antifungal activity, the treatments amended with the nonsterilized supernatant resulted in the highest growth inhibition rate of about 92.9% and 87.4% at concentrations of 30% and 10%, respectively. However, the sterilized treatments (autoclaved or chloroform treated) gave a lowered but significant inhibitory effect of about 63.4% and 62.6% for the 10% supernatant concentration, and 75.2% and 74.8% for the of 30% supernatant concentration in the PDA agar medium, respectively, indicative of the role of a non-protein, heat stable compound on the overall effect. This antifungal compound, which inhibited spore germination and altered hyphal morphology, was extracted by EtOAc and purified by ODS, silica gel, Sephadex LH-20 column, and HPLC, where an active fraction was confirmed to be 2-furancarboxaldehyde by GS-CI MS techniques. These results suggested that SY224 had a high potential in the biocontrol of anthracnose in pepper, mainly due to a combined effect of lytic enzymes and a non-protein, heat-stable antifungal compound, 2-furancarboxaldehyde.