• Journal of Microbiology and Biotechnology
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• v.7 no.6
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• pp.402-408
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• 1997

The antibiotic-producing strain HW-003 was screened from soil and found to be effective against the multidrug-resistant Staphylococcus aureus. The spore chain of HW-003 was retinaculiaperti, and the spore surface was spiny. Strain HW-003 has a LL-diaminopimelic acid isoform in the cell wall. The aerial mass color of the strain was gray, and the reverse side was yellow-brown. The strain produced melanin, but did not produce soluble pigments. According to the Taxon program, HW-003 showed best match with Streptomyces cyaneus. Antibiotic production reached a maximum after 72-h cultivation. The antibiotic was purified with silica gel column chromatography, octadecylsilyl column chromatography, and HPLC. The purified antibiotic, AMRSA1, showed strong inhibitory activity against multidrug-resistant Staphylococcus aureus and gram-positive bacteria. The molecular weight of AMRSA1 was about 1, 100. AMRSA1 was a peptide antibiotic containing alanine and serine.

• Journal of Microbiology
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• v.37 no.4
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• pp.200-205
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• 1999

7-Aminocephalosporanic acid (7-ACA) is the initial compound in preparation of cephalosporin antibiotics widely used in clinical treatment. Bacteria producing glutaryl 7-ACA acylase, which convert cephalosporin C to 7-ACA, has been screened in soil samples. A bacterial strain exhibiting high glutaryl 7-ACA acylase activity, designated KAC-1, was isolated and identified as a strain of Pseudomonas diminuta by characterizing its morphological and physiological properties. The screening procedures include culturing on enrichment media containing glutaric acid, glutamate, and glutaryl 7-aminocephalosporanic acid as selective carbon sources. To enhance enzyme production, optimal cultivation conditions were investigated. This strain grew optimally at pH 7 to 9 and in temperatures of 20 to 40 C, but acylase production was higher when the strain was grown at 25 C. Glutaric acid, glutamate and glucos also acted as inducers for acylase production. In a jar fermenter culture, P. diminuta KAC-1 produce acylase in a growth-associated manner. The substrate specificity of KAC-1 acylase by cell extract showed that this enzyme had specificity toward glutaryl 7-ACA, glutaryl 7-ADCA, but not cephalosporin C.

• Korean Journal of Breeding Science
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• v.42 no.4
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• pp.329-338
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• 2010

Drought, salinity and flooding are three important abiotic factors limiting soybean production worldwide. Irrigation, soil reclamation, and drainage systems are not generally available or economically feasible for soybean production. Therefore, productive soybean varieties with tolerance are a cost effective means for reducing yield losses due to these factors. Genetic variability for higher tolerance to drought, salt and flooding is important. However, only a small portion of nearly 200,000 world soybean accessions have been screened to find genotypes with tolerance for use in breeding programs. Evaluation for tolerance to drought, salinity and flooding is difficult due to lack of faster, cost effective, repeatable screening methods. Soybean strains with higher tolerance to the above stresses have been identified. Crosses with lines with drought, salt and flooding tolerance through conventional breeding has made a significant contribution to improving tolerance to abiotic stress in soybean. Molecular markers associated with tolerance to drought, salt and flooding will allow faster, reliable screening for these traits. Germplasm resources, genome sequence information and various genomic tools are available for soybean. Integration of genomic tools coupled with well-designed breeding strategies and effective uses of these resources will help to develop soybean varieties with higher tolerance to drought, salt and flooding.

• The Korean Journal of Pesticide Science
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• v.9 no.1
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• pp.60-69
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• 2005

The herbicide molinate has been detected with high frequency in the main river during the growing season in Korea. To elucidate the exposure of molinate in agricultural environment, the persistence and the degradation characteristics of molinate were investigated in paddy ecosystems. The half-lives of molinate were 4.1 days with soil aquatic system, and 4.2 days in only aquatic system. Initial dissipation rate of molinate in water was greater with soil aquatic system than that of only aquatic system. Photolysis of molinate was occurred about 31.0% of molinate treated in pure water, when irradiated at 5,530 $J/cm^2$ by the xenon lamp, but its hydrolysis was stable. For the accelerated photolysis of molinate in aqueous solution, several photosensitizers were screened, showing that the hydroperoxide($H_2O_2$) and acetone were prominent among the chemical tested. When hydroperoxide and zinkoxide(ZnO) were used as photosensitizer, their photolysis were accelerated greater than 98% and 58% in aqueous solution, respectively. Elution rate of molinate as granular formulations in aqueous system was more than 90% in 30 hour at $35^{\circ}C$. Molinate concentration pattern in paddy water was rapidly decrease from treatment till 7 days in paddy rice field and its half-lives were 3.7 days($Y=1.9258{\times}e^{-0.1865X}$(r=-0.9402)).

• Applied Biological Chemistry
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• v.50 no.4
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• pp.262-267
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• 2007

To access the natural product antibiotics produced by uncultured microorganisms, six cosmid libraries of DNA extracted directly from soil samples (environmental DNA, eDNA) were constructed and screened for the production of antibacterial active molecules. Of the approximately 60,000 clones screened, one antibacterial clone (YS92B) was detected. Ethyl acetate extracts of clone YS92B showed antibacterial activity against various pathogenic bacteria (Listeria monocytogenes, Bacillus subtilis, Pseudomonas syringae, Xanthomonas campestris pv. oryzae, Staphylococcus epidemis). Active constituents from cultures of YS92B were isolated and purified using a bioassay-guided fractionation against B. subtilis through a series of procedures (ethyl acetate extraction, Sephadex LH20 column chromatography, High Performance Liquid Chromatography). NMR (Nuclear Magnetic Resonance) spectral analysis of a major antibacterial active YS92B-VII indicated that it is a lauric acid linked to tyrosine. This report describes the characterization of antibacterially active long chain N-acyl derivatives of tyrosine that are produced by eDNA clones hosted in Escherichia coli from Korean soils.

• Journal of the Korean Society of Groundwater Environment
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• v.3 no.1
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• pp.27-36
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• 1996

The Nanji landfill is one of the biggest uncontrolled landfill in terms of its size and scale in the world. Because the landfill was constructed on the very vulnerable alluvial deposit installing no pollution control systems such as bottom liner and leachate collection systems, it has caused a serious adverse effect to near-by groundwater and surface water systems. A through remedial investigation comprising plume detection and site-characterization was performed to design the remedial measure. As a part the investigation, comprehensive water quality study was conducted, using ten existing observation wells and one bundle type monitoring well, to determine the contaminant indicators for the plume delineation and to define the vertical and horizontal variation of specific contaminants via distances from the landfill. The results clearly shows that EC and temperature are a good pollution indicators and the vertical concentrations of specific contaminants measured in the fully screened wells are 20 to 90% more than those measured at the same depth in bundle type well which is located just 2 m apart. This paper presents a cost effective monitoring and sampling method to define the contaminant plume and obtain a basic data for leachate control measures.

• 한국균학회소식:학술대회논문집
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• 2014.05a
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• pp.43-43
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• 2014

White rot fungi have been useful source of enzymes for the degradation of environmental pollutants including polycyclic aromatic hydrocarbons (PAHs) and synthetic dyes. PAHs are widespread organic compounds present in fossil fuels and are routinely generated by incomplete fuel combustion. PAHs are some of the major toxic pollutants of water and soil environments. Synthetic dyes are major water-pollutants, which are toxic to organisms in water environments and interfere photosynthesis of water plants. Removal of PAHs and synthetic dyes has been of interests in the environmental science especially in the environmental microbiology. Mushrooms are fungal groups that function as primary degraders of wood polyphenolic lignin. The ligninolytic enzymes produced by mushroom, including manganese peroxidase, lignin peroxidase, and laccase, mediate the oxidative degradation of lignin. The catalytic power of these enzymes in the degradation of aromatic ring compounds has been sought for the degradation of various organic compounds. In this project, we have screened 60 wild mushroom strains for their degradation activity against two representative PAHs, naphthalene and anthracene, and five aromatic dyes, including alizarin red S, crystal violet, malachite green, methylene blue, rose bengal. The degradation of PAHs was measured by GC while the decolorization of dyes was measured by both UV spectrophotometer and HPLC. As results, 9 wild mushroom strains showed high activity in degradation of PAHs and textile dyes. We also describe the secretive enzyme activities, the transcription levels, and cloning of target genes. In conjunction with this, activities of degradative enzymes, including laccase, lignin peroxidase, and Mn peroxidase, were measured in the liquid medium in the presence of PAHs and dyes. Our results showed that the laccase activity was directed correlated with the degradation, indicating that the main enzyme acts on PAHs and dyes is the laccase. The laccase activity was further simulated by the addition of $Cu^{2+}$ ion. Detailed studies of the enzyme system should be sought for future applications.

• Korean Journal of Microbiology
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• v.34 no.1_2
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• pp.37-42
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• 1998

The microorganisms degrading levan were screened from soil. The isolated strain produced levanase releasing single oligosacchride from levan. The optimum cultural medium for levanase production (g/l) was composed of 0.5% levan, 0.1% $K_2HPO_4$, 0.05% NaCl, 0.3% $NaNO_3$, 0.3% yeast extract (pH 8.0). The cultivation for levanase production was carried out in 500 ml shaking flask containing 50 ml of the optimum medium at $30^{\circ}C$ on a reciprocal shaker, and the highest levanase production was observed after 54 hours of cultivation. The levanase hydrolyzed levan into single oligosaccharide. The product purified by chilled EtOH precipitation and gel filtration was detected as a single peak on HPLC analysis. The oligosaccharides formed by enzyme reaction was identified as levanheptaose (DP7) by HPLC and by ESI-MASS.

• Mycobiology
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• v.46 no.2
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• pp.138-146
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• 2018

Two-hundred and fifty-five strains of actinomycetes isolated from soil samples were screened for their antagonistic activities against four well-known wood decay fungi (WDF), including a brown rot fungus, Gloeophyllum trabeum and three white rot fungi Donkioporia expansa, Trametes versicolor, and Schizophyllum commune. A dual culture assay using culture media supplemented with heated or unheated culture filtrates of selected bacterial strains was used for the detection of their antimicrobial activity against four WDF. It was shown that Streptomyces atratus, S. tsukiyonensis, and Streptomyces sp. greatly inhibited the mycelial growth of the WDF tested compared with the control. To evaluate the biocontrol efficacy of S. atratus, S. tsukiyonensis, and Streptomyces sp., wood blocks of Pinus densiflora inoculated with three selected Streptomyces isolates were tested for weight loss, compression strength (perpendicular or parallel to the grain), bending strength, and chemical component changes. Of these three isolates used, Streptomyces sp. exhibited higher inhibitory activity against WDF, especially G. trabeum, as observed in mechanical and chemical change analyses. Scanning electron microscopy showed that cell walls of the wood block treated with Streptomyces strains were thicker and collapsed to a lesser extent than those of the non-treated control. Taken together, our findings indicate that Streptomyces sp. exhibits the potential to be used as a biocontrol agent for wood decay brown rot fungus that causes severe damage to coniferous woods.

• Korean Journal of Microbiology
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• v.32 no.3
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• pp.232-237
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• 1994

Microorganism producing glutaryl 7-aminodeacetoxycephalosporanic acid (GL-7-ADCA) acylase was screened from soil. The microorganism was identified as Alcaligenes sp. J-421 by its morphology and biochemical properties. Cultural conditions of Alcaligenes sp. J-421 were investigated for the production of GL-7-ADCA acylase. Optimum medium composition was 1% glucose, 1% beef extract, 0.5% yeast extract, 0.2% monosodium L-glutamate, 0.1% glutaric acid, 0.2% NaCl, 0.5% $K_2$ $HPO_4$, and 0.05% $CuSO _4{\cdot}5H_2O$. Optimum cultivation conditions for the production of the enzyme in 5 l jar fermentor were $37^{\circ}C$, tip speed 300 rpm, aeration 1 vvm. Optimum reaction pH of the enzyme was 8.0 and the enzyme was stable at pH7.0-11.0.