• The Korean Journal of Mycology
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• v.12 no.3
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• pp.85-92
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• 1984

To isolate antibiotic-producing microorganisms from Korean soils, microbes were isolated from the soil samples and screened for antibacterial activity. A strain which was isolated from the soil sample collected in Choong Chung Book Do had a high antibacterial activity against gram-positive bacteria. The examination of morphological and physiological characteristics of that strain according to the International Streptomyces Project methods showed that it was one of Streptomyces species. After the antibacterial constituent of the strain was produced in submerged culture method, it was isolated and purified by XAD-2 and CM-Sephadex column chromatography. And it was found to be one of quinone type antibiotics.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.225-230
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• 2002

중부 옥천대 구룡산층 분포지역에서, 채석장 지류는 특징적으로 낮은 pH와 높은 EC를 나타내는 산성광산폐수의 형태를 보이고 있었으며, 황갈색 철 침전물을 나타내고 있었다. 이들은 탄산염이 풍부한 화전리층(상층) 지류와의 혼합으로 백색 알루미늄 침전물을 형성시켰으며, 따라서 산성수의 영향 범위가 크게 나타나지 않는 것으로 확인되었다. 포화지수와 열역학 데이터를 이용한 결과, 본 연구지역 채석장 지류에 황갈색 침전물을 생성시키는 용존철은 래피도크로사이트와 침철석의 복합적인 작용에 의해 농도가 조절되고 있음을 확인하였다.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.94-98
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• 1985

A laboratory experiment was conducted to find out the denitrification rate upon the different levels of nitrogen fertilizer in submerged sandy soil. The results obtained were summarized as follows: 1. The highest denitrification rate was observed at 25 days after incubation. The amount was reached at 1830 ug/100g soil for 20mg nitrogen was applied in 100g soil. 2. Increases of fertilizer nitrogen was enhanced the rate of ammonification and nitrification during the incubation time. 3. Deep correlation was observed between the denitrification capacities which was determined as nitrous oxide and Mitchaelis-Menten kinetic with relation to nitrate concentration. More higher denitrification rates were observed in Mitchaelis-Menten kinetic than dentrification rate with determined as nitrous oxide. 4. A Zero order (with relation to nitrate concentration) kinetic model for denitrification was presented in this experiment condition to illustrate the variability of nitrous oxide concentrations in the submerged soil atmosphere.

• Microbiology and Biotechnology Letters
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• v.20 no.2
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• pp.156-163
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• 1992

Bacillus sp. was isolated from soil for its strong activity of cyclodextrin glucanotransferase (CGTase, EC 2.4.1.19). The enzyme was purified by gel filtration and anion exchange column chromatography using FPLC. The purified enzyme exhibited its maximum CGTase activity in the pH range of 6~8 and the temperature range of 50~$70^{\circ}C$. The molecular weight was estimated as 114,000 by SDS-PAGE. The isoelectric point of the enzyme was 4.3. The CGTase of Bacillus sp. E l produced $\beta$-cyclodextrin mainly and did not produce a-cyclodextrin. The product ratio of $\beta$-cyclodextrin to $\gamma$-cyclodextrin was 7:l.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.2
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• pp.179-183
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• 1987

A series of laboratory experiments were conducted to find out the populations and identification of soil bacteria, fungi and their B/F ratio in the rhizosphere of intensively cultivatad hot-pepper, garlic, flower plants, chinese cabbage, and round onion. The results obtained are summarized as follows: 1. The number of bacteria, fungi and their B/F ratio are remarkably lower than that of normal paddy soils. 2. Nitrate reducers and bacteria which utilized simple sugars for their sole carbon source are predominated in the rhizosphere of intensively cultivated upland crops. 3. Alkaligenetic bacteria predominate in rhizosphere of garlic and tomato cultivated upland soils. 4. Genera of Pseudomonas, Xanthomonas, Bacillus, Arthrobacter, and Achromobacterium are the most common species in the rhizosphere of intensively cultivated upland crops and flower plants. 5. Phytotoxin producers such as Stachybotris sp. were identified in all rhizospheres of intensively cultivated upland crops and flower plants. 6. Most common and highest population of soil fungi were obtained for the genera of Penicillium, Humicola, Phoma and Aspergillus in the rhizosphere of intensively cultivated upland crops and flower plants.

• The Korean Journal of Mycology
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• v.13 no.4
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• pp.203-212
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• 1985

Of 450 strains isolated from the soil microbes collected in various locations in Korea, a strain had a strong inhibitory activity against bacterial ${\alpha}-amylase$ and was named strain DMC-72 of the genus Streptomyces. The amylase inhibitory metabolite produced by this strain was purified by means of acetone precipitation, adsorption on Amberlite IRC-50 and SP-Sephadex C-25. The inhibitor was found to be a derivative of oligosaccharides by spectral and chemical data. The inhibitor was stable at the pH range of $1{\sim}13$ and at $100^{\circ}C$ for half an hour, also inhibited other amylases such as salivary ${\alpha}-amylase$, pancreatic ${\alpha}-amylase$, fungal ${\alpha}-amylase$ and glucoamylase. However, it showed no inhibitory activity against ${\alpha}-glucosidase$, ${\beta}-glucosidase$, dextranase, and ${\beta}-amylase$. The kinetic studies of the inhibitor showed that its inhibitory effects on starch hydrolysis by ${\alpha}-amylase$ were noncompetitive.

• Journal of The Geomorphological Association of Korea
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• v.18 no.3
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• pp.21-36
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• 2011

Rock Weathering is a basic of geomorphological evolution as a preparation of materials. Of those, frost shattering has traditionally been considered as the operative process causing rock breakdown in cold regions as well as temperate zone. Each Granite(fresh rock, semi-weathered), Gneiss, Limestone, Dolomite was prepared slab specimens in ten, repeated freeze-thaw cycles of 180 under the -25℃~+30℃, and the changes was observed in physical properties and weathering aspect. Rock shattering was more active in waterlogging conditions rather than atmospheric and soil conditions. Limestone and Dolomite that high porosity are most severely crushed. Gneiss, regardless surface of the crack, joint, fissure and has a lowest rock strength(SHV), was even though no physical changes and their weathering product do not generate, has a very high resistance to weathering.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.2
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• pp.129-134
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• 1988

Enzymatical properties of Streptomyces sp. S-45 producing chitinase and ${\beta}$-1.3-glucanase isolated from soil were investigated. Chitinase activity was 3.01(U/ml) and ${\beta}$-1.3-glucanase activity was 2.49(U/ml). The optimum medium for mycolytic enzyme production of strain was composed of 0.7% colloidal chitin, 0.3% glucose, 0.5% asparagine, 0.2% peptone, 0.01% NaCl, 0.01% $K_2HPO_4$ and 0.01% $MgSO_4{\cdot}7H_2O$ in intial pH 7.0. The optimal condition for mycolytic enzyme activities were: pH 6.5-7.0, $45-50^{\circ}C$. Enzyme activities were activated by metal ion as $10^{-2}M\;Co^{{+}{+}}$, $Cu^{{+}{+}}$, $Mn^{{+}{+}}$, $Al^{{+}{+}{+}}$ and $10^{-3}M\;Sn^{{+}{+}}$ but $Ag^{{+}{+}}$, $Hg^{{+}{+}}$ inhibited.

• Applied Biological Chemistry
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• v.26 no.1
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• pp.53-57
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• 1983

Butachlor incubated for certain periods of time under the simulated, rather aerobic, rice-paddy conditions of two different soils exhibited two major degradation products. 2,6-diethyl-N-(butoxymethyl) acetanilide and a new product C in all cases, and a relativly small amount of another new product D named tentatively as 8-ethyl-2-hydroxy-N-(butoxymethyl)-3,4-dihydroquinoline in some cases. The supposedly microbial degradation seemed to proceed with incubation periods to some extent. An anaerobic incubation in the previous investigation showed 2,6-diethyl-N-(butoxymethyl) acetanilide as the major product, whereas the new product C with m/z 291 turned out to be the major one in the present condition. Structural elucidation of the products was done based on the fragmentation patterns of the given mass spectra and a possible pathway for their formation was postulated.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.35-40
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• 1997

This study was conducted to investigate methane emission under different rice cultural practices in paddy soil (Jeonbug Series, occurring on fluvio-alluvial plain). The rates of application of fresh rice straw were 5,000kg/ha in combination with 110 and 160kg N/ha as chemical fertilizer. The methane emission among the rice cultural practices was in the order of transplanting cultivation, direct seeding on flooded surface and direct seeding on dry paddy field. The average methane flux was $10.27mg/m^2/h$ in direct, seeding on dry paddy field and $24.1mg/m^2/h$ in transplanting cultivation. The diurnal variation of methane emission at heading stage was high from 9 a.m. till 7 p.m. and the methane emission rate was highly correlated with air temperature fluctuation and soil Eh. The seasonal change of methane flux was high from ear formation stage to heading stage.