• Korean Journal of Microbiology
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• v.52 no.4
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• pp.437-443
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• 2016

In this study Streptomyces strains were isolated from soils and their antifungal activities and involved mechanisms were investigated. Among over 400 isolates of actinomycetes, Streptomyces costaricanus HR391 was selected as a potential antagonist to control several plant-pathogenic fungi. S. costaricanus HR391 inhibited mycelial growth of Fusarium oxysporum f. sp. raphani, F. oxysporum f. sp. niveum, F. oxysporum f. sp. lycopersici, and Rhizoctonia solani by 26.5, 26.2, 21.2, and 23.8%, respectively compared to those of uninoculated control after 7-day incubation on PDB medium. S. costaricanus HR391 produced $89{\mu}M$ of siderphore, and showed fungal cell wall-degrading activity including $0.46{\mu}mol/min/mg$ of chitinase and $0.83{\mu}mol/min/mg$ of ${\beta}$-1,3 glucanase. S. costaricanus HR391 secreted 87.49 mg/L of rhamnolipid, and produced 9.49 mg/L and 4.3 mM of lipopeptide, iturin A and surfactin, respectively, all they are membrane-disrupting biosurfactants. It also produced antimicrobial peptide and antibiotics phenazine. In addition to antifungal substances, S. costaricanus HR391 secreted plant growth-promoting phytohormones, zeatin, gibberellins and IAA. These results suggest that S. costaricanus HR391 may be utilized as an environment-friendly biocontrol agent against some important pathogenic fungi.

• Asian Journal of Turfgrass Science
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• v.26 no.1
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• pp.8-16
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• 2012

The objective of this study was to identify bacterial antagonists of R. solani AG2-2 (IV) on zoysiagrass and to evaluate their antifungal activity in vitro and in vivo to select an antagonistic isolate. Antagonistic isolates that inhibit large patch disease caused by R. solani AG2-2 (IV) in zoysiagrass were selected from several soils, and their antagonistic activities were investigated in vitro and in vivo. Of 216 bacterial isolates, 67 inhibited several plant pathogenic fungi. The isolates that inhibited stem-segment colonization by R. solani AG2-2 (IV) in zoysiagrass were tested in a growth chamber. Eleven isolates were active as plant growth promoting isolates. Among them, five plant growth promoting isolates and their concentration dependent efficiency on zoysiagrass following inoculation with R. solani AG2-2 (IV) was evaluated. Isolate H33 was one of the potential antagonistic isolates, and it was further tested against various plant pathogens. H33 not only suppressed the disease caused by R. solani AG2-2 (IV) on zoysiagrass but also promoted leaf weight and leaf height of zoysiagrass under growth chamber and greenhouse conditions. The H33 isolate, which belongs to Streptomyces arenae, was identified through physiological, biochemical, and 16S rDNA studies. Further studies will investigate the cultural characterization of S. arenae H33 and isolation and identification of antifungal substance produced by S. arenae H33.

• Korean journal of applied entomology
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• v.49 no.2
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• pp.151-158
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• 2010

Among 18 Bacillus thuringiensis isolates with spherical parasporal inclusion from soils, B. thuringiensis subsp. israelensis CAB199 was selected. It was showing over 90% mortality against Aedes aegypti and Culex pipiens moletus. It was confirmed that this B. thuringiensis subsp. israelensis CAB199 isolate also had a insecticidal activity against Culex inatomii that was occurred in the marsh. Because most of mosquito larva were primarily situated or shifted from under- to surface water, we need to select long floating formulations on surface water for controlling mosquito larva. It was tested the pesticidal and control effects in the laboratory and wetland with two formulation types of B. thuringiensis subsp. israelensis, for example, wettable power (WP) and suspension concentrate type (SC). Laboratory test showed that SC formulation type was relatively faster and more effective against 3 tested mosquito species, C. pipiens, Aedes aegypti, and C. inatomii. Otherwise, the control efficacy of SC formulation type was more rapidly appeared against C. inatomii in the wetland.

• Korean Journal of Agricultural Science
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• v.9 no.1
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• pp.377-386
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• 1982

This experiment was carried out to elucidate the thermotolerant properties of a thermophilic bacterium which was isolated from soils of the hot springs area and selected for the ${\beta}$-galactosidase production. This bacterium was identified as a strain belong to the genus Thermus. Biochemical and physiological characteristics of this strain were studied, including the investigation of the fatty acid composition of its neutral fats. The results obtained were summarized as follows. 1. Optimal temperature and pH for growth of this strain were $65^{\circ}C$ and pH 6.5 respectively, and it was found to be an absolute thermophilic bacterium which could not grow at the temperature below $43^{\circ}C$. 2. No growth was obtained in the medium which contained more than 1.0% of sodium chloride. 3. The tolerable concentration of antibiotics were 10mg of penicillin G per ml of medium and 0.5mg of chloramphenicol per ml respectively. 4. This strain had auxotrophilic requirements for calcium-pantothenate and pyridoxin-HCl as an essential factor and for niacin as a stimulative factor. 5. Yellow pigment was released into the liquid culture of this strain, which showed maximum absorption at 420 nm. 6. Fatty acid composition of neutral fats of the strain was palmitic acid, 60.20%; lauric acid, 11.80%; myristic acid, 7.56%; behenic acid, 4.25%; capric acid, 1.77%; stearic acid, 2.13%; arachidic acid, 1.53%; and others unidentified, 10.7%.

• Journal of Plant Biology
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• v.13 no.1
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• pp.33-46
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• 1970

Pinus densiflora stands are common secondary forest communities on infertile soils in Korea. The stands are results of long severe past biotic pressure such as cutting, burning and grazing. These could be regarded as biotic climax in Korea. Because of their prevalent occurrence, relatively simple species and age composition, and their domestic economic importance, study of their distributional patterns may give some basic knowledge for better utilization of land resources in Korea. To detect distributional patterns and interspecific associations ten pine stands, each of which was homogenious with respect to topography and physiognomy, were subjectively selected from pine stands in Kyunggi Province near Seoul in 1969 and were made object of this study. Four contiguous systematic samples of count for trees, shrubs and seedlings from belt transects were collected from homogeneous areas within ten natural pine stands. The belt transect was 64m or 128m in length, and 1m, 2m or 4m in width. Basic units within the transect ranged from 64 to 256. The data from the contiguous transects were analysed in terms of multiple split-plot experiment. Departure from randomness of stem distribution, i.e., pattern, was tested in terms of variance mean ratio. For the detection of association between species, correlation coefficient was calculated for different block sizes. The values of ${\gamma}$ were tested by the usual t-test. Fine trees within one of the stands showed significant regular distribution through out the blocks. Within other eight stands pines were randomly distributed at basic unit with 4$\times$4m, 2$\times$2m, 2$\times$1m and 1$\times$1m. One significantly clumped distribution at basic unit 2$\times$2m, however, was observed from one of the pine stands. These randomly distributed groups were themselves significantly regularly distributed throughout the blocks for four pine stands. For the other four pine stands, in addition to the random distribution at the basie unit(the primary random group), randomly distributed groups with 32m dimension(the secondary random groups) were also observed. Both the primary and the secondary random groups were significantly regularly distributed at the rest of blocks. Pine seedlings were not distributed randomly thoughout the blocks. Within three of the ten stands they were contagiously distributed. Important shrub species underneath pines such as Querus serrata, Q. acutissima, Leapedeza intermedia, Rhododendron Yedoense var. poukhanenae, Juniperus utilis, Rhododendron mucronulatum var. ciliatum shnwed consistently similar distributional pattern with the pine at each stand. The shrub species pairs; Rhododendron Yedoense var. poukhanenae/Quercus serrata, Rhododendron mucronulatum var. ciliatum/Lespedeza intermedia were significantly negatively associated from 1m to 4m dimensional block sizes but became significantly positively associated from 8m sized blocks on. On the other hand the shrub species pairs; Lespedeza intermedia/Robinia Pseudoacacia, and Lespedeza bicolor var, japonica/Lespedeza intermedia were also significnalty negatively associated from 1m to 8m sized blocks but became significantly positively associated from 16m sized blocks on. The associational pattern between Rhododendron mucronul tun var. poukhanenae and Lespedeza intermedia was not consistent throughout the stands. In some stands negative associations were observed throughout the blocks except NS 32. From these observatons micro-edaphic variation within the pine stands seems not to be great enough to cause distributinal difference of pine trees within the ten pine stands. Among each species and pine seedings, however, the edaphic variation within the pine stands may be great enought to cause distributional variation.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.127-127
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• 2017

Aluminum is the most abundant metallic element in the Earth's crust and considered as the most limiting factor for plant productivity in acidic soils. The inhibition of root growth is recognized as the primary effect of Al toxicity. Seeds of wheat cv. Keumkang (Korean cultivar) were germinated on petridish for 5 days and then transferred hydroponic apparatus which was treated with $0{\mu}M$ $AlCl_3$ (control), $100{\mu}M$ $AlCl_3$ and $150{\mu}M$ $AlCl_3$ for 5 days. The length of roots, shoots and fresh weight of wheat seedlings were decreased under aluminum stress. The concentrations of $K^+$, $Mg^{2+}$ and $Ac^{2+}$ were decreased whereas $Al^{3+}$ and $P_2O_5{^-}$ concentration was increased under aluminum stress. Using confocal microscopy, the fluorescence intensity of aluminum was increased with morin staining. In this study, a proteome analysis was performed to identify proteins, which is responsible to aluminum stress in wheat roots. In 10-day-old seedlings, proteins were extracted from roots and separated by 2-DE, stained by CBB. Using image analysis, a total of 47 differentially expressed protein spots were selected, whereas 19 protein spots were significantly up-regulated such as s-adenosylmethionine, oxalate oxidase, malate dehydrogenase, cysteine synthase, ascorbate peroxidase and 28 protein spots were significantly down-regulated such as heat shock protein 70, o-methytransferase 4, enolase, amylogenin by aluminum stress following protein spots analyzed by LTQ-FTICR mass spectrometry. The results provide the global picture of Al toxicity-induced alterations of protein profiles in wheat roots, and identify the Al toxicity-responsive proteins related to various biological processes that may provide some novel clues about plant Al tolerance.

• Korean Journal of Organic Agriculture
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• v.24 no.2
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• pp.221-234
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• 2016

The application of animal manure on farm fields is one of the most economical ways. However, the continuous application of manure in paddy fields might change soil properties influencing the growth of rice plant. Thus, this study was conducted to investigate the changes in selected chemical and biological properties of soils and rice production as affected by the applications of two different fertilizer sources, which were the consecutive applications of liquid swine manure (LSM) and chemical fertilizer (CF), during the three experimental years, from 2012 to 2014. Application amount of LSM was based on 100% of nitrogen fertilizer recommendation rate for rice cultivation estimated by soil testing. Plant height and tiller number in rice at the first year of liquid swine manure manure plot were lower than those of chemical fertilizer plot. Height and tillers of rice in liquid swine manure plot were higher than those of rice in chemical fertilizer plot after consecutive application for 3 years. Rice yield In the first year of application was decreased by 7% than that of chemical fertilizer, but the yield of rice in the third year of application in LM 100% plot was increased by 8% compared to the chemical fertilizer. Toyo-taste value of milled rice in LM 100% was decreased by increasing of protein contents and decreasing rate of perfect grain. The K and Zn contents in the soil were increased in the plots of consecutive LSM application. The results implied that the liquid manure may neither decrease the yield of rice and nor increase soil properties except K and Zn in the soil, and decrease rice quality.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.2
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• pp.81-85
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• 1989

The 113 soils representing the Jisan soil series (fine loamy, mixed, mesic fluventic Haplaquepts) as mapped in Korea were to characterize the Jisan soil throughout its official range which was the range of properties used to establish series limits. The samples were stratified according to master horizon designation for statistical analysis. The means in selected soil properties, horizon thickness, solum thickness, soil texture, clay content, pH, BSP, and horizon sequence, were within acceptable limits. The minimum values were considerably lower than the lower limits of the official ranges while the maximum values were above the allowable amount. The ranges of definition degree which mean the test of proper placement of any marginal limits were 0.687 to 0.929. Thus, Jisan series as mapped from other soil bodies in the field could be seen similarities and understood relationships among individuals.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.6
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• pp.779-784
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• 2003

Nitrate a common component of man's chemical environment, is present in foods either naturally or in an additive introduced during processing of foods. Nitrate level of foods have been found depending on nitrosation of soils and other various environmental factors. Therefore data on nitrate contents of foods reported in other countries can not be adapted to Korean foods. Also data on nitrate levels of Korean foods available were reported 10 years ago, which would be assumed to differ from those of foods currently consuming by Koreans. The present study was attempted to determine nitrate contEnts of common foods. Based on National Nutrition Survey Report 143 food items out of 14 food groups were selected for this study Nitrate levels of common foods used in the study were from N.D (not detected) to 6733.33 mg/kg foods. Mean nitrate levels of food groups 27.2 mg/kg of cereal and grain products, 78.1 mg/kg in potatoes and potato products, 8.3 mg/kg in legumes and their products N.D of seeds and nuts, 1012.1 mg/kg of vegetables and their products,76.3 mg/kg fungi and mushrooms 42.2 mg/kg fruits,34.5 mg/kg of meat, poultry and their products,0 mg/kg in eggs, 23.9 mg/kg in fish, shellfishes and their products,23.0 mg/kg in seaweeds, 7.7 mg/kg milk and dairy products, 26.3 mg/kg in seasonings, 68.0 mg/kg in others.

• The Korean Journal of Pesticide Science
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• v.3 no.1
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• pp.90-95
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• 1999

For the control of the greenhouse whitefly, Trialeurodes vaporariorum entomopathogenic fungi were isolated from forest soils and infected insects. We selected three strains, which showed high pathogenicity and named as SFB-582(Beauveria sp.), SFP-198(Paecilomyces fumosoroseus) and SFV-1053(Verticillium sp.) respectively. Particularly, at the concentration of $10^{7}$ conidia/ml, P. fumosoroseus SFP-198 had the highest pathogenicity, $91.4{\pm}3.5%$ in laboratory. In glasshouse application, $91.4{\pm}3.5%$ SFP-198 showed high protective values($80{\sim}90%$) regardless of developmental stages, which were similar with that of Verticillium lecanii F-903 already reported. Four kinds of formulations of entomopathogenic fungi were developed, formulation with surfactant Silwet L-77 gave best control of greenhouse whitefly(over 90%). These results suggest that P. fumosoroseus SFP-198 is a promising candidate as a microbial pesticide for the control of T. vaporariorum.