• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.62-67
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• 1997

A potential biocontrol bacterium, YB-70 was isolated from a rhizosphere in suppressive soil and identified as a strain of Bacillus subtilis. In several biochemical and in vitro antibiosis tests on Fusarium solani with the culture filterates from B. subtilis YB-70, we found that antifungal mechanism of B. subtilis YB-70 was mediated by antibiotic substances produced from the bacterium. These antifungal substances were appeared to be hear-resistant, micromolecular, and ethy alcohol soluble. Antifungal agents produced by B. subtilis YB-70 showed strong inhibified against root-rotting fungi F. solani in in vivo pot test. An antifungal substance. YBS-1s, was purified from the culture broth of B. subtilis YB-70 by isoelectronic precipitation, silica gel column chromatography and Sephadex LH-20 column chromatography analysis by Fab-MASS, $^{1}$H-NMR, $^{13}$C-NMR, DEPT, and amino acid analyzer revealed that the YBS-1A was a peptide antibiotics of iturin class containing seven amino acids from five different groups, and the other(YBS-1B) was an analogue of iturin group composed of 11 amino acids with larher molecular weight of about 1, 500 dalton, which was lager than that of iturin A.

• Journal of Life Science
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• v.16 no.3 s.76
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• pp.387-395
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• 2006

To isolate and purify anti-fungal active substances from immunized housefly (Musca domestica), low dose of Candida albicans was injected into the larvae of the housefly to induce the appearance of potent anti-fungal active substances in the hemolymph. This purification work was performed by the routine isolation and purification processes of protein, namely, solid phase extraction (SPE), SDS-PACE electrophoresis, HPLC purification. Three 4-16 kDa peptides which exhibited antifungal activity against Candida albican and other fungi were isolated from induced hemolymph. Consequently, further anti-fungal activity study showed that these three peptides were different either in molecular weight or in anti-fungal activity. All isolated substances were proved to be active and resistant to high-temperature. It was deduced that these peptides isolated from induced housefly were novel members of the insect defensin family and they were inducible.

• The Plant Pathology Journal
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• v.40 no.3
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• pp.322-328
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• 2024

Soybean (Glycine max), a crucial global crop, experiences yearly yield reduction due to diseases such as anthracnose (Colletotrichum truncatum) and root rot (Fusarium spp.). The use of fungicides, which have traditionally been employed to control these phytopathogens, is now facing challenges due to the emergence of fungicide-resistant strains. Streptomyces bacillaris S8 strain S8 is previously known to produce valinomycin t through a nonribosomal peptide synthetase (NRPS) pathway. The objective of this study was to evaluate the antifungal activity of S. bacillaris S8 against C. truncatum and Fusarium sp., assessing its efficacy against soybean pathogens. The results indicate that strain S8 effectively controlled both above-ground and underground soybean diseases, using the NRPS and NRPS-related compound, suggesting its potential as a biological control in plant-microbe interactions. These findings underscore the pivotal role of the stain S8 in fostering healthy soybean microbial communities and emphasize the significance of microbiota structure studies in unveiling potent biocontrol agents.

• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.805-810
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• 2000

An antifungal protein antagonistic to the rice blast fungus, Pyricularia oryzae was purified from Paenibacillus macerans PM-1 by ammonium sulfate fractionation, Q Sepharose Fast Flow column chromatography, Phenyl Sepharose CL-4B column chromatography and Superose 12 gen filtration. An apparent molecular mass of the purified antifungal protein was determined as 8 kDa by SDS-PAGE and 9 kDa by analytical gel filtration, respectively, suggesting that the purified protein is a monomer. The antifungal protein was stable at pH range from 7-12 and up to $100^{\circ}C$. The protein was also stable at 0.1-1% Tween 20 and Triton X-100. The N-terminal amino acid sequence of the antifungal protein was Thr-Glu-Leu-Pro-Leu-Gly-Ile-Val-Met-Asp-Lys-Tyr-Thr-Asp-Ala-Phe-Lys-Phe-Asp-Met-Phe. Comparison of the determined sequence with other peptide and DNA sequences did not reveal homology at all. Therefore, the purified antifungal protein was speculated to be a novel protein. The condidial germination in vitro of P. oryzae KJ301:93-39 by the purified protein ($5.9{\mu} g/ml$) was limited to $9{\pm}3.2%$ only, compared with $69{\pm}2.4%$ of the control. Ungerminated conidia were swollen at basa and mid cell by the purified protein. In vivo bioassay for inhibition of conidial germination of P. oryzae KJ 301, one of the most predominating racesin Korea. the purified protein ($5.9{\mu} g/ml$)strongly inhibited the conidial germination. The conidia, even though germinated, could not develop any further to produce appressoria efficiently.

• Journal of Microbiology and Biotechnology
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• v.19 no.10
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• pp.1169-1175
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• 2009

An antifungal chitinase, ChiCW, produced by Bacillus cereus 28-9 is effective against conidial germination of Botrytis elliptica, the causal agent of lily leaf blight. ChiCW as a modular enzyme consists of a signal peptide, a catalytic domain, a fibronectin type-III-like domain, and a chitin-binding domain. When two C-terminal domains of ChiCW were truncated, $ChiCW{\Delta}FC$ (lacking the chitin-binding domain and fibronectin type III-like domain) lost its antifungal activity. Since $ChiCW{\Delta}C$ (lacking the chitin-binding domain) could not be expressed in Escherichia coli as $ChiCW{\Delta}FC$ did, a different strategy based on protein engineering technology was designed to investigate the involvement of the chitin-binding domain of ChiCW ($ChBD_{ChiCW}$) in antifungal activity in this study. Because ChiA1 of Bacillus circulans WL-12 is a modular enzyme with a higher hydrolytic activity than ChiCW but not inhibitory to conidial germination of Bo. elliptica and the similar domain composition of ChiA1 and ChiCW, the C-terminal truncated derivatives of ChiA1 were generated and used to construct chimeric chitinases with $ChBD_{ChiCW}$. When the chitin-binding domain of ChiA1 was replaced with $ChBD_{ChiCW}$, the chimeric chitinase named ChiAAAW exhibited both high enzyme activity and antifungal activity. The results indicate that $ChBD_{ChiCW}$ may play an important role in the antifungal activity of ChiCW.

• Journal of Integrative Natural Science
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• v.1 no.1
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• pp.47-53
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• 2008

In a previous study, we showed that Cecropin A (1-8)-Magainin 2 (1-12) hybrid peptide (CA-MA)'s analogue, Anal P5, exhibit broad-spectrum antimicrobial activity. Anal P5, designed by flexible region (positions 9, 10)-substitution, Lys- (positions 4, 8, 14, 15) and Leu- (positions 5, 6, 12, 13, 16, 17, 20) substitutions, showed an enhanced antimicrobial and antitumor activity without hemolysis. The primary objective of the present study was to gain insight into the relevant mechanisms of antimicrobial activities of Anal P5 by using flow cytometric analysis. Anal P5 exhibits strong antifungal activity in a salt concentration independent manner. In addition, Anal P5 causes significant morphological alterations of the bacterial surfaces as shown by scanning electron microscopy, supporting its antibacterial activity. Its potent antibiotic activity suggests that Anal P5 is an excellent candidate as a lead compound for the development of novel antibiotic agents.

• YAKHAK HOEJI
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• v.49 no.5
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• pp.422-427
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• 2005

Our previous data showed the protein isolated from Coptidis Rhizoma (CRP) had antifungal activity. In present study, we examined mode of action of the CRP and its activity against subcutaneous candidiasis due to C. albicans yeast cells. Results showed that the CRP blocked hyphal production from yeast form of C. albicans. The CRP also activated RAW 264.7 monocyte/macrophage cell line, which resulted in nitiric oxide (NO) production from the cells. This activation seemed to increase macrophage phagocytosis to destroy the invaders. Like other antimicrobial peptides, CRP was influenced by ionic strength, thus resulting in a decrease of antifungal activity. In murine model of a subcutaneous candidiasis, the sizes of infected areas of the nude mice given the CRP after subcutaneous injection of C. albicans yeast cells to the dorsal skin were $90\%$ less than those of the nude mice groups that received DPBS instead of the CRP. All data indicate that the CRP, which appeared to act like an antimicrobial peptide and to inhibit the morphological transition from blastoconidia, was effec­tive against the subcutaneous disease.

• KSBB Journal
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• v.25 no.2
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• pp.123-129
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• 2010

An endospore-forming, rod-shaped bacterium was isolated from forest soil samples collected at the Taebaek mountain of Gangwon province, Korea, and taxonomically characterized by physiological, biochemical and phylogenetic methods. Its 16S rRNA sequences showed the maximum similarity of 97% with B. amyloliquefaciens. In addition, the isolate BCNU 2002 was determined to have the ability to produce enzymes such as amylase, protease, gelatinase and catalase. The in vitro antifungal activity of Bacillus sp. BCNU 2002 was also examined against human pathogenic fungi such as Aspergillus niger, Candida albicans, Epidermophyton floccosum, Saccharomyces cerevisiae, Trichophyton mentagrophytes and Trichophyton rubrum. A maximum production level of antifungal substances of Bacillus sp. BCNU 2002 was achieved under aerobic incubation at $28^{\circ}C$ for 7 days in LB broth. BCNU 2002 showed strong antifungal activities against T. mentagrophytes and T. rubrum with the range of percentage inhibition from 56.25 to 63.23%. It was also confirmed that ethylacetate extract of cultured broth showed a strong antifungal activity against A. niger, C. albicans, S. cerevisiae and T. rubrum by agar diffusion method. The peptide fraction also exhibited broad antifungal spectrum against various pathogenic fungi. The minimum inhibitory concentration values for active extracts ranged between 125 ${\mu}g$/mL and 1000 ${\mu}g$/mL.

• Microbiology and Biotechnology Letters
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• v.19 no.6
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• pp.598-603
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• 1991

An antifungal mixture of six members (component A to F), KRF-001 produced by Bacillzts subtilis subsp. krictiensis was isolated from the fermentation broth. Molecular weight of component A to F was determined by FAB-MS to be 1042, 1056, 1056, 1070, 1070 and 1084 respectively. Various instrumental analyses (amino acid analysis, GC-MS, $^1H-NMR, ^1HH$ COSY NMR) revealed that the mixture was a homologous cyclic peptide composed of each one mole of glutamine, proline, tyrosine, serine, unusual $\beta$-amino acid and three moles of asparagine. The structural differences of component A to F were found in carbon number and terminal structure of the unusual $\beta$-amino acid. After determination of the sequence and stereochemistry of those amino acids, the tentative structure of KRF-001 was determined.

• Journal of Mushroom
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• v.14 no.4
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• pp.162-167
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• 2016

Lactic acid bacteria (LAB) producing phenyllactic acid (PLA), which is known as antimicrobial compound, was isolated from button mushroom bed and the isolated LAB was identified to Lactobacillus casei by 16 rRNA gene sequence analysis. Cell-free supernatant (CFS) from L. casei was assessed for both the capability to produce the antimicrobial compound PLA and the antifungal activity against three fungal pathogens (Rhizoctonia solani, Botrytis cinerea, and Collectotricum aculatum). PLA concentration was investigated to be 3.23 mM in CFS when L. casei was grown in MRS broth containing 5 mM phenylpyruvic acid as precursor for 16 h. Antifungal activity demonstrated that all fungal pathogens were sensitive to 5% CFS (v/v) of L. casei with average growth inhibitions ranging from 34.58% to 65.15% (p < 0.005), in which R. solani was the most sensitive to 65.15% and followed by C. aculatum, and B. cinerea. The minimum inhibitory concentration (MIC) for commercial PLA was also investigated to show the same trend in the range of 0.35 mg mL-1 (2.11 mM) to 0.7 mg mL-1 (4.21 mM) at pH 4.0. The inhibition ability of CFS against the pathogens were not affected by the heating or protease treatment. However, pH modification in CFS to 6.5 resulted in an extreme reduction in their antifungal activity. These results may indicate that antifungal activities in CFS was caused by acidic compounds like PLA or organic acids rather than protein or peptide molecules.