Sun-Chul Kang

Anti-listerial compounds from Asari Radix

Asari Radix, the roots of Asarum heterotropoides F. Maekawa var. manshuricum F. Maekawa or A. sieboldii F. Maekawa, has traditionally been used for the treatment of various infectious diseases. Since its MeOH extract inhibited the growth of Listeria monocytogenes in a preliminary test, the aim of this study was to isolate and identify the anti-listerial compounds from the plant. Activity-guided fractionation led to the isolation of seven compounds 1–7 from the MeOH extract, and their chemical structures were identified by comparison of the spectroscopic data with those in the literature. Compounds 1–7 exhibited inhibitory activity against all five tested strains of L. monocytogenes with diameter of inhibition zones ranging from 7 to 11 mm in the agar disc diffusion method. Compounds 1–3 and 7 demonstrated potent antimicrobial effects on the L. monocytogenes strains, with MICs between 62.5 and 125 μg/mL. This is the first report that AR possesses inhibitory activity against L. monocytogenes.

Preparation of enantiomerically pure (R)-2-butyryloxymethylglycidol by lipase-catalyzed asymmetric hydrolysis

Abstract Optically active epoxy alcohol, (R)-2-butyryloxymethylglycidol3 which is the precursor of a tert-alcohol chiral building block was obtained in high enantiomeric purity, 98.7% e.e., by lipase-catalyzed asymmetric hydrolysis using a phosphate buffer and organic co-solvent system in 95% of chemical yield.

A diterpenoid taxodone from Metasequoia glyptostroboides with antimycotic potential against clinical isolates of Candida species

OBJECTIVE The increasing importance of clinical isolates of Candida species and emerging resistance of Candida species to current synthetic antifungal agents have stimulated the search for safer and more effective alternative drugs from natural sources. This study was directed towards exploring the antimycotic potential of a diterpenoid compound taxodone isolated from Metasequoia glyptostroboides against pathogenic isolates of Candida species. MATERIALS AND METHODS Antimycotic efficacy of taxodone was evaluated by disc diffusion assay, determination of minimum inhibitory (MIC) and minimum fungicidal (MFC) concentrations, and cell viability assay. To confirm a partial antimycotic mode of action of taxodone, the efficacy of taxodone was determined by measuring the release of 260 nm absorbing materials from the selected Candida species as compared to control. RESULTS The taxodone at the concentration of 400 μg/disc displayed potential antimycotic effect against the tested clinical and pathogenic isolates of Candida species as diameters of zones of inhibitions, which were found in the range of 11 ± 0.0 to 12.6 ± 0.5mm. The MIC and MFC values of taxodone against the tested clinical isolates were found in the range of 250 to 1000 and 500 to 2000μ g/mL, respectively. On the other hand, the MIC and MFC values of positive control (amphotericin B) against the tested Candida isolates were found in the range of 62.5 to 250 and 500 to 2000 μg/mL. On the viable counts of the tested fungal isolates, the taxodone exerted significant antimycotic effect. Elaborative study of partial mode of action conducted onto the release of 260nm materials (DNA and RNA) revealed potential detrimental effect of taxodone on the membrane integrity of the tested pathogens at MIC concentration. CONCLUSION With respect to the antimycotic effect of taxodone against pathogenic and clinical isolates of Candida species, it might be confirmed that bioactive compound taxodone present in M. glyptostroboides holds therapeutic value of medicinal significance.

Anti-oxidizing functional effect of polyamine as a bioconversion starter using microbes isolated from fluke babsikhae

Polyamines are well known as important molecular compounds for many biochemical processes in animals and plants. The function of biogenic polyamine has been especially well studied for its role in the oxidative system and the protection of membranes from peroxidation in cells. We investigated the polyamine contents of fluke babsikhae and isolated polyamineproducing lactic acid bacteria (LAB) to improve the probiotic antioxidative function of the Korean traditional fermented food, fluke babsikhae. In the present study, first we confirmed that fluke babsikhae possesses more antioxidative molecules compared to the other antioxidative vegetable (Korean radish) and ascorbic acid by using the method of peroxide value (POV). Secondly polyamines, which are considered as antioxidative molecules, were detected in fluke babsikhae using thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). In order to improve the probiotic function of fluke babsikhae, LABs were isolated from the fermented food, and these isolated microbes were tentatively identified as Lactobacillus brevis strain bh3 and Lactobacillus sp. using 16S rRNA sequencing. Polyamine was produced from these two strains and also was confirmed to have antioxidative activity. Especially Lactobacillus sp. was shown to produce high amounts of putrescine. Therefore, this strain can be considered as a starter to improve the probiotic function of fluke babsikhae. According to the results, fluke babsikhae will be a good candidate for a healthy functional food and also isolated LAB will be considered as a starter for probiotics by bioconversion.

Characterization and Antifungal Activity from Soilborne Streptomyces sp. AM50 towards Major Plant Pathogens

BACKGROUND: Chemical fungicides not only may pollute the ecosystem but also can be environmentally hazardous, as the chemicals accumulate in soil. Biological control is a frequently-used environment-friendly alternative to chemical pesticides in phytopathogen management. However, the use of microbial products as fungicides has limitations. This study isolated and characterized a three-antifungal-enzyme (chitinase, cellulase, and β-1,3-glucanase)-producing bacterium, and examined the conditions required to optimize the production of the antifungal enzymes. METHOD AND RESULTS: The antifungal enzymes chitinase, cellulase, and β-1,3-glucanase were produced by bacteria isolated from an sawmill in Korea. Based on the 16S ribosomal DNA sequence analysis, the bacterial strain AM50 was identical to Streptomyces sp. And their antifungal activity was optimized when Streptomyces sp. AM50 was grown aerobically in a medium composed of 0.4% chitin, 0.4% starch, 0.2% ammonium sulfate, 0.11% Na2HPO4, 0.07% KH2PO4, 0.0001% MgSO4, and 0.0001% MnSO4 at 30℃. A culture broth of Streptomyces sp. AM50 showed antifungal activity towards the hyphae of plant pathogenic fungi, including hyphae swelling and lysis in P. capsici, factors that may contribute to its suppression of plant pathogenic fungi.

Isolation and Morphological Characterization of Monilinia sp. KV-27 Associated with Apple Anthracnose of Fuji Apples in Korea

This study was undertaken to isolate and to identify a fungal pathogen Monilinia sp. KV-27 associated with apple anthracnose. Rotted Fuji apples were used for the isolation of the fungus. The infected tissues were sterilized with 70% ethanol, washed with sterilized distilled water and were transferred to 50 ml containing potato dextrose broth (PDB) flasks. The peripheral hyphae of the fungal colony which developed from the infected tissues were isolated on to potato dextrose agar (PDA). On PDA plates the fungus grew well at and occupied more than half of a 9 cm petri dish within 5 days. The fungal cultures on PDA were used for morphological observation and identification of the fungus. Conidiophores were produced on the gray to whitish sporodochial structures scattered on PDA plates. These conidiophores gave rise to chains of conidia, which were branched and easily detached in water. These structures were dark brown to black and consisted of hyphal masses. Conidia produced on PDA plates were hyline or light colored, lemon shaped or ellipsoidal () in size.

Solubilization of Insoluble Phosphates by Aspergillus sp. PS-104 Isolated from Soil

Phosphate-solubilizing microorganisms were isolated from soil around Kyungnam and Kyungbook regions using potato dextrose agar-calcium phosphate medium. A fungus with the greatest phosphate-solubilizing activity was selected and identified to Aspergillus sp. PS-104, based on the morphological characteristics of conidiophore and conidia; unbranching type of conidiophore, terminally swelling of conidiophore and septate of mycelium, in malt extract agar and potato dextrose agar media. The optimum temperature and initial pH to solubilize rock phosphate in potato dextrose broth-rock phosphate medium were and pH 7.0, respectively. In these optimum conditions, phosphate-solubilizing activities of Aspergillus sp. PS-104 against four twos of insoluble phosphate, tricalcium phosphate, aluminium phosphate, hydroxyapatite and rock phosphate, were quantitatively determined. As result, the maximum phosphate-solubilizing activity was obtained with tricalcium-phosphate (1,900 ppm) while minimum activity was obtained with hydroxyapatite (320 ppm). Futhermore, phosphate-solubilizing activity of Aspergillus sp. PS-104 was found higher when treated with nitrates as compared to the ammonium salts as a nitrogen sources.

Effect of Additives on the Conidial Viability of Aspergillus sp. PS-104

A fungus, Aspergillus sp. PS-104, with the high phosphate-solubilizing activities was isolated from Korean upland soil and formulated into a solid powder type with various additives. For the long-time preservation of conidia, some additives (Tween 80, SDS, Triton X-100, glucose, glycerol, corn oil, bio-ceramic, PEG 200, , , , and ) were supplemented in the rice-cooked hard medium with various concentrations (0, 0.001, 0.01, 0.1, 1.0 and 5.0%). In case of surfactants. the highest relative viability of the Aspergillus sp. PS-104 conidia was recorded nearly to 80% by the addition of 0.01 to 0.1% Tween 80, while 50% in control. The number of conidia were found to be about 100 times higher when treated at 0.01 to 0.1% Tween 80 as compared to control. Relative viability of the conidia was decreased in order of Tween 80 SDS > Triton X-100 during the storage at . As regards the organic additives, the relative viability of Aspergillus sp. PS-104 conidia was also recorded nearly to 80% by the addition of 1.0% bio-ceramic, and 5.0% glucose and sucrose during the storage at . In case of metal ions, the relative viability of Aspergillus sp. PS-104 conidia was decreased in order of

Optimization of Mutant Strain of the Sulfur-Oxidizing Bacteria, Thiobacillus sp. UIW-6

Cu^{2+}>Ca^{2+}>Mo^{3+}>Zn^{2+}>Fe^{2+}

Establishment of a near-standard two-dimensional human urine proteomic map

during the storage at .