• 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.

• The Korean Journal of Food & Health Convergence
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• v.9 no.6
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• pp.1-7
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• 2023

Secondary metabolites in the culture filtrates of lactic acid bacteria offer varied chiral moieties, making them a valuable resource for drug design scaffolding. Our previous methodology included using a combination of anion exchange resins, Amberlite IRA-67 and Purolite A420S, to purify significant quantities of Lactobacillus plantarum LBP-K10 peptidyl compounds. However, current experimental evidence regarding the impact of native culture extracts and/or filtrates on pathogenic fungi in vivo/in vitro is insufficient. This study analyzed the antifungal properties of two different probiotic cultures: the CH₂Cl₂-extracted filtrate of Chinese cabbage kimchi (CH₂Cl₂-extracted CCK_WLB and CH₂Cl₂-extracted CCK_WOLB) and the non-extracted filtrate of Chinese cabbage kimchi (non-extracted CCK_WLB and non-extracted CCK_WOLB). The samples were divided into two groups: one group was inoculated with probiotics while the other group remained non-inoculated. Filtrates from both experimental groups were utilized for antifungal assays. The treatments employing CCK_WLB, with an initial inoculation of Lb. plantarum LBP-K10 as a starter, demonstrated significant antifungal activity under various experimental conditions. Our study offers new perspectives on the antifungal properties of CH₂Cl₂-extracted kimchi filtrates, which are naturally produced by lactobacilli. The efficacy of antifungal compounds is supported by substantial evidence demonstrating their efficient uptake by cells and the antifungal properties exerted by metabolites.

• The Korean Journal of Mycology
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• v.26 no.4 s.87
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• pp.458-465
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• 1998

The strain DGUM 5051, an antagonistic bacterium against apple-bitter rot causing Glomerella cingulata, was isolated from soil in Kyongju. Based on the morphological and physiological characteristics, the bacterium was identified as Pseudomonas sp. and named as Pseudomonas sp. DGUM 5051. The optimal pH and temperature for cell growth were pH 6.0 and $30^{\circ}C$, whereas those for antifungal activity were pH 7.0 and $24^{\circ}C$, respectively. Among the complex media tested, brucella medium, brain heart infusion medium and Luria-Bertani medium were good for both cell growth and antifungal activity. The high antifungal activity was found in the mineral salts medium, in which sucrose, $KNO_3$ and $K_2HPO_4$ were used as sources of carbon, nitrogen and phosphorus, respectively.

• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.811-816
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• 2000

An antagonistic bacterium PM-1 which strongly inhyibits the growth of Pyricularia oryzae was isolated and identified as paenibacillus macerans. The antifungal substances of the strain PM-1 showed the broad antifungal spectra against P.oryzae races. Relating to the localization test, it was found that the antifungal substances existed not only in the cytoplasm but also in the culture supernatant, and importantly the antifungal activity of the latter was stronger than that of the former. The extracellular antifungal substances were extremely heat-stable up to $121^{\circ}C$ for 15 min. The substances were optimally produced at $20^{\circ}C$ and pH 10.0 in a potato dextrose broth. The culture filtrate of the strain PM-1 caused a partial swelling of the mycelia of P.oryzae, and it prevents the normal growth of the fungus as well. This result suggested that the antifungal substances secreted by the strain PM-1 potentially inhibited the germination of P.oryzae.

• 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.

• Microbiology and Biotechnology Letters
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• v.25 no.3
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• pp.335-337
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• 1997

In this study, we show a convenient MTT assay for detect the susceptibility of yeast-like form of Trichosporon beigelii against antifungal agents. This assay was developed based on mitocondrial respiration by determining reduction of 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) to formazan. Cells of T beigelii are seeded into 96-well microtiter plates, and antifungal agents, amphotericin B, magainin and CA-ME hybrid peptide were added with various concentrations. After 24 hr incubation, MTT was added, then incubations were continued for 4 hr. Formazan formation was quantified photometrically after extraction of the formazan with acid sodium dodesyl sulfate (SDS). From this assay, we could obtained MICs of antifungal agents against T. beigelii. The presented method can easily be used as an effective methods to assess the antiftingal action of various agents on yeasts with minimal amounts of antifungal agents.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.319-324
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• 2010

Phorbol ester extraction was carried out from Jatropha curcas seed cake, a by-product from the biodiesel fuel industry. Four repeated extractions from 5 g of J. curcas seed cake using 15 ml of 90% (v/v) ethanol and a shaking speed of 150 rpm gave the highest yield of phorbol esters. The ethanolic extract of J. curcas seed cake showed antifungal activities against important fungal phytopathogens: Fusarium oxysporum, Pythium aphanidermatum, Lasiodiplodia theobromae, Curvularia lunata, Fusarium semitectum, Colletotrichum capsid, and Colletotrichum gloeosporioides. The extract contained phorbol esters mainly responsible for antifungal activities. The extract could therefore be used as an antifungal agent for agricultural applications.

• Korean Journal of Environmental Biology
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• v.18 no.4
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• pp.441-446
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• 2000

Trichoderma harzianum is an aggressive causal agent of green mold disease on mushroom cultivation. Some bacterial strains isolated, from oyster mushroom compost in Wonju, were found to have in vitro antifungal activity against Trichoderma harzianum ATCC 6385, 6504, and our isolates Trichoderma spp. Y and G. Further in vitro antifungal studies on several strains of phytopathogenic fungi showed that all of 12 phytopathogenic fungal strains were significantly inhibited by the isolated antifungal bacteria in Petri dishes. Of these, KATB 99121 showed the broadest inhibiting effect and displayed as negative coagulase, negative sulfide production and rod shape. KATB 99121 was resistant to ampicillin, chlorampenicol, and kanamycin. Identification of isolates was determined by Biolog GN system, and KATB 99121 was identified as Photobacterium logei because of 96 probability, 0.65 similarity, and 4.97 disturbance. With electron microscopy, thin section of KATB 99121 strain revealed typical rod-like shaped cell (0.6-0.8${\mu}{\textrm}{m}$$\times$1.5-2.0${\mu}{\textrm}{m}$) with prokaryotic structure and organization.

• 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.8 no.3
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• pp.197-202
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• 1998

Aliphatic alkenals having 6 to 13 carbons were evaluated for antifungal activity against Saccharomyces cerevisiae. The activity was gradually increased with chain length, e.g., (E)-2-decenal and (E)-2-undecenal exhibited maximum potency, while (E)-2-dodecenal and (E)-2-tridecenal were completely inactive. Alkenals showed increasing inhibitory activity with chain length, as in the case of antifungal activity, towards glucose-induced medium acidification by the plasma membrane $H^+$-ATPase of S. cerevisiae. The group including (E)-2-nonenal, (E)-2-decenal, and (E)-2-undecenal exhibited maximum potency, but the potency of (E)-2-dodecenal and (E)-2-tridecenal demonstrated a sudden drop with respect to the former group. (E)-2-Nonenal revealed dose-responsive inhibition to the medium acidification and inhibited over 90% at a concentration of 1.25 mM ($175.3{\mu}g$/ml). In contrast to (E)-2-undecenal whose inhibitory efficiency increased with incubation time, inhibition by (E)-2-dodecenal was reversed with time. Of the tested alkenals, (E)-2-heptenal and (E)-2-octenal most highly inhibited ATP hydrolytic activity by the plasma membrane $H^+$ ATPase, while (E)-2-heptenal at 10 mM ($1121.8{\mu}g$/ml) showed an inhibitory efficacy of 93.2%.