• Korean Journal of Microbiology
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• v.32 no.3
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• pp.208-214
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• 1994

We screened many species from a wide variety of bacterial genera for a new type II restriction endonuclease. The purification and characterization of SolI from a soil isolate, Streptoverticillium olivoverticillatum are described here. The enzyme turned out to be an isoschizomer of BamHI. It recognized the hexanucleotide sequence of 5'-G$\downarrow$GATCC-3' and cleaved as in dicated by the arrow, generating a 4 base 5' extension. Unlike its isoschizomer, BamHI, the activity was sensitive to dam methylation within the recognition sequence. Following ammonium sulfate fractionation of the crude extract, heparin-agarose and Affi-gel Blue column chromatography were employed to purify the enzyme. SolI required at least 0.2 mM of $MgCl_2$ for the cleavage to occur. The enzyme exhibited its maximal activity in the absence of NaCl, but was inhibited completely in the presence of 120 mM NaCl. The pH and temperature optima for activity were pH 8.6 and $40^{\circ}C$, respectively. The molecular weight of SolI was estimated to be 43,000 Da by Superose-12 gel filtraion chromatography.

• Journal of Conservation Science
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• v.31 no.4
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• pp.443-455
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• 2015

To verifying the stability of Natural pigments for Dancheong which is available on the market was carried out as light resistance and gas corrosion test. In this particular case, we will confirm the characteristics of the only pigments except of Dancheong technique and influence of substance. Medium using for coloring are animal glue and synthetic resin that widely used for Dancheong in currently. Selected to artificial light source is a xenon arc lamp, contaminated gas is nitrogen dioxide gas in experiment. Degree of degradation of pigment were compared by measuring the degree of color change. The result of light resistance test, mineral pigments were good; color is green and blue type, soil pigments also good; color is yellow ocher, white clay, red clay etc. Gamboge, unghwang, cinnabar, red lead were confirmed not good. The result of gas corrosion test, most of the natural pigments were good condition except the red lead. Generally, animal glue samples had better than a synthetic resin samples.

• Weed & Turfgrass Science
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• v.6 no.1
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• pp.32-39
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• 2017

This study was carried out to investigate the ACCase inhibiting herbicide resistant Echinochloa oryzicola collected in a Honam rice field and to investigate the control of E. oryzicola in directly seeded paddy rice field. The study result showed that about 44% of the 67 biotypes collected in the rice field in Honam region were resistant to ACCase-inhibiting herbicides. The efficacy of several chemical herbicides on these resistant E. oryzicola biotypes was evaluated according to their application timings. Among herbicides applied 4 days before seeding, pretilachlor, butachlor, oxadiazon, oxadiargyl, oxadiazon+pretilachlor, and fentrazamide+oxadiargyl, provided 95% or higher control of the resistant E. oryzicola biotypes. Among the herbicides applied 10 days after seeding, bromobutide+fentrazamide+imazosulfuron, benzobicyclon+fentrazamide+imazosulfuron, pyrazosulfuron-ethyl+thiobencarb, fentrazamide+imazosulfuron, bromobutide+imazosulfuron+mefenacet and bromobutide+imazosulfuron+pyraclonil provided ${\geq}95%$ control of the weeds. Bromobutide+imazosulfuron+mefenacet and bromobutide+pyrazosulfuron-ethyl+pyriminobac-methyl, applied 15 days after seeding, provided ${\geq}95$ and 90% control of the weeds. Foliar application of cyhalofop-butyl+propanil at 30 days after seeding provided ${\geq}90%$ control of the weeds. In addition, oxaziclomefone provided ${\geq}90%$ control for 40 days after soil application. These results show that E. oryzicola biotypes resistant to ACCase-inhibiting herbicides could be effectively controlled in directly seeded rice in submerged paddy fields using single or tank-mixed chemical herbicides currently available on the market.

• Korean Journal of Microbiology
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• v.32 no.1
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• pp.91-95
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• 1994

EagBI is a type II restriction endonuclease from Enterobacter agglomerans strain CBNU45 isolated from soil. EagBI was partially purified by DEAE-cellulose, phosphocellulose P11 and hydroxylapatite column chromatography. EagBI recognizes and cleaves the sequence 5'-CGAT${\downarrow}$CG-3' and generates 2-base 3'-protruding cohesive ends. The optimal reaction conditions of EagBI are 10 mM Tris-HCl (pH 7.8), 6-10 mM $MgCl_2$, at 37 ${\circ}C$. The enzyme is maximally active in the absence of NaCl, able to cleave both $dam^-$ and $dam^+$ DNAs, and sensitive to heat treatment (at 65 ${\circ}C$ for 10 min). Therefore, although EagBI is an isoschizomer of PvuI, it is more useful than PvuI in respect of the NaCl requirement and heat-stability.

• Journal of the Korean earth science society
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• v.31 no.4
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• pp.313-321
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• 2010

The landform of the study area is defined as a small-scale alluvial plain in the valley bottom adjacent to the coast. By the aggradation of alluvial materials, this valley bottom plain was formed in dissected parts of low hills. For the purpose of reconstructing the palaeo climate environment in this study, $\delta^{13}C$ analysis and soil organic carbon analysis are therefore employed. Main results of this study are as follows: Section I: the period of $6,600{\pm}60yr$ B.P.$-5,350{\pm}60yr$B.P. was mostly in warm and humid climate environment. A little changes of the humid environment are detected as subdry (or sub-humid)${\rightarrow}$humid in terms of the dryness and wetness. Section II: the period of $5,350{\pm}60yr$ B.P.-2,200 yr B.P. was in warm and humid climate environment, which is similar to the present. However, The sediments between $4,720{\pm}60yr$ B.P. and $4,210{\pm}50 yr$ B.P. experienced the most humid climate environment of all studied sedimentary layers. After $4,210{\pm}50 yr$ B.P., the environment started to change from the humid to the sub-humid (or sub-dry) climate. Section III: the period of 2,200 yr B.P.$-210{\pm}60 yr$ B.P. was distinguish from previous two sections as the environmental changes to sub-humid (or sub-dry) climate was apparent.

• Journal of the Korean earth science society
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• v.33 no.4
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• pp.320-328
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• 2012

To investigate geomorphic development of alluvial plains and climatic environment change during the late Holocene carbon dating, soil organic carbon analysis and humus analysis of sediments from alluvial plain of Hampyeongcheon basin were performed. The lowest peat layer was formed under warm and humid climates, which is considered to correspond to the Atlantic period in the Holocene. Yellowish brown sandy clay layer was deposited in the natural levee, which we think were deposited in the generally warm and dry climates. The carbon dating age is 1,879-1,532 BC, and this period correspond to the Sub-boreal period in the Holocene. Light brown clay layer is assumed to have been deposited in transitional environment from the natural levee to the back marsh. The climatic environment was warm and humid, which is considered as transitional period from the Sub-boreal to the Sub-Atlantic in the Holocene. Light yellowish brown and light brown clay layer of the upper part are regarded as sediments of the back marsh. Light yellowish brown clay layer was deposited in the cold and dry climates, which is considered to correspond to the Sub-Atlantic period in the Holocene. Light brown clay layer was deposited in the warm and dry climates. The carbon dating age is 211-427 AD, this period corresponds to the Post Roman Warm Period in the Holocene.

• Journal of Korean Society of Forest Science
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• v.55 no.1
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• pp.22-29
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• 1982

Two ectomycorrhizal fungi, Pisolithus tinctorius and Thelephora terrestris, were introduced form U.S.A. and inoculated to five pine species in Korea to evaluate the reported growth stimulation of host plants after inoculation. These fungi were grown as mycelial inoculum in large quantity and ioculated to the fumigated nursery soil just before seed sowing. At the end of the first growing season. Pisolithus stimulated the height growth of Pinus densiflora. P. thunbergii. P. rigida, and P. rigida x teada by55, 36, 69, and 37%, respectively, compared with control seedlings with no fumigation and no inoculation. When the growth stimulation was expressed with dry weight, Pisolithus increased dry weight of P. densiflora and P. rigida x taeda by 143% and 128%, respectively, over control seedling. Thelephora failed to stimulate growth of inoculated plants. Pinus koraiensis did not respond to the inoculation during the first growing season. It is concluded that artificial inoculation of nursery pine trees with selected mycorrhizal fungi should be seriously considered to improve the quality of planting stocks and to stimulate early plant growth. The potential for use of Pisolithus in reforestation on adverse sited is also discussed.

• Applied Biological Chemistry
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• v.34 no.4
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• pp.299-306
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• 1991

When $[U-^{14}C]$ 3,3', 4,4'-tetrachloroazobenzene$([U-^{14}C]\;TCAB)$ was added to the $MM_2$ medium as a sole carbon source for the isolated microorganisms and incubated, some radioactive metabolites were detected by autoradiography. No $^{14}CO_2$ was evolved from $[U-^{14}C]\;TCAB$ which was added as a sole carbon source to an organic matter-free soil inoculated by the isolates, wetted with the $MM_2$ salt medium, and incubated at $30^{\circ}C$. One of the metabolites in pure culture of Achromobacter group VD, which was isolated and identified, was tentatively identified as a compound of m/z 250 by means of GC/MS. The possible pathways for its formation are thought to include dechlorination from the TCAB structure, hydroxylation, ortho fission of the two benzene rings, and reduction of the resulting carboxyl group.

• The Journal of Engineering Geology
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• v.17 no.3
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• pp.359-365
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• 2007

Freezing and thawing cycle is one of the major weathering-induced factors in the mechanical weathering of the rock mass. This natural process accelerates rock weathering process by breaking down the parent rock materials and makes soil or weathered rock formation in a rock slope surface zone. It can also cause reduction of the shear strength in slopes. It is important to calculate the deterioration depth caused by freezing-thawing for a slope stability analysis. In this study, deterioration depths of rock slope due to freezing-thawing were calculated using the 1-D heat conductivity equation. The temperature distribution analysis was also carried out using collected temperature distribution data for last five years of several major cities in Korea. The analysis was performed based on the distributed rock types in study areas. Thermal conductivities, specific heats and densities of the calculation rocks are tested in the laboratory. They are thermal properties of rocks as input parameters for calculating deterioration depths. Finally, the paper is showing the calculated deterioration depths of each rock type slopes in several major cities of Korea.

• Korean Journal of Weed Science
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• v.17 no.4
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• pp.382-389
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• 1997

Collated data from the 1995-1996 floristic surveys of weeds of arable peat in Selangor district were analysed to assess composition and dominance and spatial distribution pattern based on quantitative and dispersion indices. Forty eight weed species belonging to 19 families of which 31 were broad leaves, 10 grasses and 7 sedges were sampled and these ware translated as 77.8 and 15% of the total cover, respectively, The respective important values were 71.11 and 18%. Ten species in the onder of dominance were Fimbristylis acuminata, Murdannia nudiflora, Hedyotis corymbosa, Ageratum conyzoides, Asystasia gangetica, Cleome rutidosperma, Cyperus sphacelatus, Lindernia crustacea, Ludwigia hyssopifolia of spatial distribution based on variance-to-mean ratios, Llouds mean crowding or Lloyds patchiness indices. Other species were either random or regular in their spatial distribution. Differences in species-dominance and spatial distribution pattern may be attributed to inherent variations in patchiness and fecundity schedules of each weed species, crops, cropping patterns and agronomic practices prevailing in the area.