• Korean Journal of Microbiology
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• v.45 no.4
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• pp.332-338
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• 2009

A xylan-decomposing bacterium, HY-20, was isolated from the gut of a honeybee, Apis mellifera, and identified as Bacillus sp. The extracellular GH11 xylanase (XylP) gene (687-bp) of strain HY-20 encoded a protein of 228 amino acids with a deduced molecular mass of 25,522 Da and a calculated pI of 9.33. The primary structure of XylP was 97% identical to that of B. pumilus xylanase (GenBank accession no.: AY526092) that has not been characterized yet. The recombinant His-tagged enzyme (rXylP) overexpressed in Escherichia coli BL21 harboring pET-28a(+)/xylP was purified to electrophoretic homogeneity by cation exchange and gel permeation chromatographies. The purified enzyme exhibited the highest catalytic activity toward birchwood xylan at pH 6.5 and $50^{\circ}C$ and retained approximately 50% of its original activity when pre-incubated at $55^{\circ}C$ for 15 min. The recombinant enzyme was completely inactivated by $Hg^{2+}$ (1 mM) and N-bromosuccinimide (5 mM), while its activity was slightly stimulated by approximately 10% in the presence of $Mn^{2+}$ (1 mM), $Fe^{2+}$ (1 mM), and sodium azide (5 mM). rXylP was able to efficiently degrade various polymeric xylose-based substrates but PNP-sugar derivatives and glucose-based polymers were not susceptible to the enzyme.

• Journal of Bio-Environment Control
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• v.26 no.2
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• pp.115-122
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• 2017

Objective of this research was to investigate the influence of lowered substrate pH on the reduction of bicarbonate injury in the vegetative growth of 'Ssanta' strawberry. The acid substrate was formulated by mixing sphagnum peat moss with pine bark (5:5, v/v) and the pH, EC, and CEC of the substrate were 4.07, $0.46dS{\cdot}m^{-1}$, and $91.3cmol^+{\cdot}kg^{-1}$, respectively. To adjust the pH of acid substrate, various amount of dolomitic lime [$CaMg(CO_3)_2$] were incorporated with the rate of 0 (untreated), 1, 2, 3, and $4g{\cdot}L^{-1}$. Then, mother plants were transplanted and grown with fertilizer solution containing $240mg{\cdot}L^{-1}$ of the $HCO_3{^-}$ and equal concentrations of essential nutrients to Hoagland solution. In growth of 'Ssanta' strawberry, fresh weight of mother plants were the highest in the treatment of $2g{\cdot}L^{-1}$ dolomitic lime such as 102.1 g followed by 94.7 g in $1g{\cdot}L^{-1}$, 91.2 g in $3g{\cdot}L^{-1}$, 75.7 g in $0g{\cdot}L^{-1}$ and 72.3 g in $4g{\cdot}L^{-1}$ treatments. The dry weight showed a similar tendency to fresh weight. At 140 days after transplanting, 5.8, 9.8, 11.8, 8.8, and 5.0 daughter plants were derived from each of the mother plants in the treatments of 0, 1, 2, 3, and $4g{\cdot}L^{-1}$ dolomitic lime, respectively. The highest occurrence of daughter plants were observed in the treatments $2g{\cdot}L^{-1}$ dolomitic lime. The substrate pH and bicarbonate concentration of 'Ssanta' strawberry seedlings in the 1 and $2g{\cdot}L^{-1}$ dolomitic lime treatments were maintained at a proper range such as 5.6 to 6.2. The micro-nutrient contents of above ground tissue in mother plants were the highest in $2g{\cdot}L^{-1}$ and the lowest in $4g{\cdot}L^{-1}$ dolomitic lime treatment. The above results indicate that incorporation rate of dolomitic lime in acid substrate with the pH of around 4 is $2g{\cdot}L^{-1}$ to raise the 'Ssanta' strawberry in propagation.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.418-429
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• 2011

Novel chromium(III), manganese(II), iron(III), cobalt(II), nickel(II), copper(II), ruthenium(III), and zirconyl(II) complexes of $N^1,N^2$-bis(3-((3-hydroxynaphthalen-2-yl)methylene-amino)propyl)phthalamide ($H_4L$, 1) have been synthesized and characterized by elemental, physical, and spectral analyses. The spectral data showed that the ligand behaves as either neutral tridentate ligand as in complexes 2-5 with the general formula $[H_4LMX_2(H_2O)]{\cdot}nH_2O$ (M=Cu(II), Ni(II), Co(II), X = Cl or $NO_3$), neutral hexadentate ligand as in complexes 10-12 with the general formula $[H_4LM_2Cl_6]{\cdot}nH_2O$ (M=Fe(III), Cr(III) or Ru(III)), or dibasic hexadentate ligand as in complexes 6-9 with the general formula $[H_2LM_2Cl_2(H_2O)_4]{\cdot}nH_2O$ (M = Cu(II), Ni(II), Co(II) or Mn(II), and 13 with general formula $[H_4L(ZrO)_2Cl_2]{\cdot}8H_2O$. Molar conductance in DMF solution indicated the non-ionic nature of the complexes. The ESR spectra of solid copper(II) complexes 2, 5, and 6 showed $g_{\parallel}$ >g> $g_e$, indicating distorted octahedral structure and the presence of the unpaired electron in the $N^1,N^2$ orbital with significant covalent bond character. For the dimeric copper(II) complex $[H_2LCu_2Cl_2(H_2O)_4]{\cdot}3H_2O$ (6), the distance between the two copper centers was calculated using field zero splitting parameter for the parallel component that was estimated from the ESR spectrum. The antibacterial and antifungal activities of the compounds showed that, some of metal complexes exhibited a greater inhibitory effect than standard drug as tetracycline (bacteria) and Amphotricene B (fungi).

• Proceedings of the Mineralogical Society of Korea Conference
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• 2002.10a
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• pp.119-136
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• 2002

Contrasts in the style of the gold-silver mineralization in geologic and tectonic settings in Korea, together with radiometric age data, reflect the genetically different nature of hydrothermal activities, coinciding with the emplacement age and depth of Mesozoic magmatic activities. It represents a clear distinction between the plutonic settings of the Jurassic Daebo orogeny and the subvolcanic environments of the Cretaceous Bulgugsa igneous activities. During the Daebo igneous activities (c.a. 200-150 (?) Ma) coincident with orogenic time, gold mineralization took place between c.a. 195 and 135 (127 ?) Ma. The Jurassic Au deposits commonly show several characteristics; prominent association with pegmatites, low Ag/hu ratios in the ore-concentrating parts, massive vein morphology and a distinctively simple mineralogy including Fe-rich sphalerite, galena, chalcopyrite, arsenopyrite, Au-rich electrum, pyrrhotite and/or pyrite. During the Bulgugsa igneous activities $(110\~50Ma)$, the precious-metal deposits are generally characterized by such features as complex vein morphology, medium to high AE/AU ratios in the ore concentrates, and diversity of ore minerals including base-metal sulfides, pyrite, arsenopyrite, Ag-rich electrum and native silver nth Ag sulfides, Ag-Sb-As sulfosalts and Ag tellurides. Vein morphology, mineralogical, fluid inclusion and stable isotope results indicate the diverse genetic natures of hydrothermal systems in Korea. The Jurassic Au-dominant deposits (orogenic type) were formed at the relatively high temperature $(about\;300^{\circ}\;to\;450^{\circ}C)$ and deep-crustal level $(4.0{\pm}1.5\;kb)$ from the hydrothermal fluids containing more amounts of magmatic waters $(\delta\;^{18}O_{H2O}\;5\~10\%_{\circ})$. It can. It can be explained by the dominant ore-depositing mechanisms as $CO_2$ boiling and sulfidation, suggestive of hypo- to mesothermal environments. In contrast, the Cretaceous Au-dominant $(l13\~68\;Ma),\;Au-Ag \;(108\~47\;Ma)$ and Ag-dominant $(103\~45\;Ma)$ deposits, which correspond to volcanic-plutonic-related type, occurred at relatively low temperature $(about\;200^{\circ}\;to\;350^{\circ}C)$ and shallow-crustal level $(1.0\{pm}0.5\;kb)$ from the ore-forming fluids containing more amounts of less-evolved meteoric waters$(\delta\;^{18}O_{H2O}\;-10\~5\%_{\circ})$. These characteristics of the Cretaceous precious-metal deposits can be attributed to the complexities in the ore-precipitating mechanisms (mixing, boiling, cooling), suggestive of epi- to mesothermal environments. Therefore, the differences of the emplacement depth between the Daebo and the Bulgugsa igneous activities directly influence the unique temporal and spatial association of the deposit styles.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.3
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• pp.245-253
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• 2007

This research was performed to evaluate the airborne personal concentration of hazardouse materials during the process of ship construction and surveyed from May 23 to June 30, 2007 in Kyungnam West Distirct, Korea. The subject was 94 ship construction workers exposed to welding fume and respirable particulate. The airborne concentrations of those were compared to Permissible Exposure Limit(PEL) from the Ministry of Labor in Korea. The airborne concentration of 23 samples(48.9%) of welding fumes was less than $5mg/m^3$, that of 16 (34.0%) was between 5 and $10mg/m^3$, and that of 8 (17.0%) was greater than $10mg/m^3$. The airborne concentration of 27 (57.4%) of respirable particulate masses was less than $5mg/m^3$ and the othere are greater than $5mg/m^3$. The welding fumes were identified containing the heavy metasl such as Fe, Mn, Zn, Mg, Ca, and Cu. The respirable particulates has similiar tendency with welding fumes in the component of heavy metals. But the concentration of Ca, Cu, Cr, and Ni turned out to be higher in welding fumes. Twenty (42.6%) of the 47 samples of welding fumes were exceeded PEL. In the heavy metals in welding fumes, ten (21.3%) of the 47 samples of Mn were exceeded PEL. Based on the results, the higher airborne hazardous materials were still exposed to wokers in ship construction process. It is suggested that the appropriate engineering control be applied to minimize the exposed cocnetration in ship building processes.

• Journal of Aquaculture
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• v.1 no.2
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• pp.109-119
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• 1988

Following the previous study on the nutritional quantity of Al, Fe, and their interrelationships with other trace metals, this study was conducted to determine the effect of supplementation of Cu and Mn to fish meal-diets on the growth of Japanese eel. The feeding experiment to determine Cu requirement was conducted using white fish meal-diets supplemented with 0, 5, 10, or 20 $\mu$g/g cupric sulfate, and that to determine Mn requirement was conducted by suppling the diet with 0, 10, 20, or 40 $\mu$g/g manganese sulfate. The results revealed that the fish on diet annexed with 5 $\mu$g/g of Cu were observed to have the best growth among these groups. In case of Mn, 20 $\mu$g/g of supplementary level promoted growth rate and 40 $\mu$g/g of diet resulted in the highest feed efficiency. On the other hand, the highest level of Cu (20 $\mu$g/g), and Mn (40 $\mu$g/g) supplementary diets did not expressed adverse effect on growth. These results indicated that the suitable Cu and Mn supplementary concentrations are 20 $\mu$g/g and 30 $\mu$g/g of formulated the white fish meal-diet respectively. The white fish meal had 1.6 $\mu$g/g of Cu and 6.1 $\mu$g/g of Mn.

• Resources Recycling
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• v.26 no.6
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• pp.84-90
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• 2017

The electro-refining process was performed to recovery high purity copper from low grade copper containing sludge in sulfuric acid. The surface morphologies and roughness of electro-refining copper were analyzed with variation of the type and concentration of organic additives, the best surface morphology was obtained 5 ppm of the gelatin type and 5 to 10 ppm of the thiol type organic additive. The crude metal consisted of copper with 86.635, 94.969 and 99.917 wt.%, several impurity metals of iron, nickel, cobalt and tin by pyro-metallurgical process. After electro-refining process, the purity of copper increases to 3N or 4N grade. The impurity concentrations and copper purities of copper crude metals, electrolyte and electro-refining copper were analyzed using ICP-OES, the electro-refining time and purity of copper crude metal to recover 4N grade copper were deduced.

• Proceedings of the Botanical Society of Korea Conference
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• 1987.07a
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• pp.133-148
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• 1987

Gibberellin(GA) 3-$\beta$ hydroxylation is very important for the shoot elogation in the higher plants, since only 3$\beta$-hydryoxylated GAs promote shoot elogation in several plants. Fluctuation of 3$\beta$-hydryoxylase activity was examined during seed maturation using two cultivars of , P. vulgaris, Kentucky Wonder (normal) and Masterpiece (dwarf). Very immature seeds of both cultivars contain high level of 3$\beta$-hydroxylase activity (per mg protein). Both cultivars showed maximum of enzyme activity (per seed) in the middle of their maturation process. Gibberellin 3$\beta$-hydroxylase catalyzing the hydroxylation of GA20 to GA1 was purified 313-fold from very early immature seeds of P. vulgaris. Crude soluble enzyme extracts were purified by 15% methanol precipitation, hydrophobic interaction chromatogrphy, DEAE ion exchange column chromatography and gel filtration HPLC. The 3$\beta$-hydroxylase activity was unstable and lost much of its activity duting the purification. The molecular weight of purified enzyme was extimated to be 42, 000 by gel filtration HPLC and SDS-PAGE. The enzyme exhibited maximum activity at pH 7.7. The Km values for [2.3-3H] GA20 and [2.3-3H]GA9 were 0.29 $\mu$M and 0.33 $\mu$M, respectively. The enzyme requires 2-oxoglutarate as a cosubstrate; the Km value for 2-oxoglutarate was 250 $\mu$M using 3H GA20 as a substrate. Fe2+ and ascorbate significantly activated the enzyme at all purification steps, while catalase and BSA activated the purified enzyme only. The enzyme was inhibited by divalent cations Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+ and Hg2+. Effects of several GAs and GA anaogues on the putrified 3$\beta$-hydroxylase were examined using [3H]GA9 and GA20 as a substrates. Among them, GA5, GA9, GA15, GA20 and GA44 inhibited the enzyme activity. [13C, 3H] GA20 was converted by the partially purified enzyme preparation to [13C, 3H]GA1, GA5 and GA6, which were identified by GC-MS, GA9 was converted only GA4, GA15 and GA44 were converted to GA37 and GA38, respectively. GA5 was epoxidized to GA6 by the preparation. This suggests that 3$\beta$-hydroxylation of GA20 and epoxidation of GA5 are catalyzed by the same enzyme in P, vulgaris.

• Proceedings of the KSEEG Conference
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• 2002.10a
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• pp.119-136
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• 2002

Contrasts in the style of the gold-silver mineralization in geologic and tectonic settings in Korea, together with radiometric age data, reflect the genetically different nature of hydrothermal activities, coinciding with the emplacement age and depth of Mesozoic magmatic activities. It represents a clear distinction between the plutonic settings of the Jurassic Daebo orogeny and the subvolcanic environments of the Cretaceous Bulgugsa igneous activities. Dunng the Daebo igneous activities (c.a. 200～150 (\ulcorner) Ma) coincident with orogenic time, gold mineralization took place between c.a. 195 and 135 (127 \ulcorner) Ma. The Jurassic Au deposits commonly show several characteristics; prominent association with pegmatites, low Ag/Au ratios In the ore-concentrating parts, massive vein morphology and a distinctively simple mineralogy including Fe-rich sphalerite, galena, chalcopyrite, arsenopyrite, Au-rich electrum, pyrrhotite and/or pyrite. During the Bulgugsa igneous activities (110～50 Ma), the precious-metal deposits are generally characterized by such features as complex vein morphology, medium to high Ag/Au ratios in the ore concentrates, and diversity of ore minerals including base-metal sulfides, pyrite, arsenopyrite, Ag-rich eletrum and native silver with Ag sulfides, Ag-Sb-As sulfosalts and he tellurides. Vein morphology, mineralogical, fluid inclusion and stable isotope results indicate the diverse genetic natures of hydrothermal systems in Korea. The Jurassic Au-dominant deposits (orogenic type) were formed at the relatively high temperature (about 300$^{\circ}$ to 45$0^{\circ}C$) and deep-crustal level (4.0$\pm$1.5 kb) from the hydrothermal fluids containing more amounts of magmatic waters ($\delta$$^{18}$ $O_{H2O}$; 5～10$\textperthousand$). It can be explained by the dominant ore-depositing mechanisms as $CO_2$ boiling and sulfidation, suggestive of hypo- to mesothermal environments. In contrast, the Cretaceous Au-dominant (l13～68 Ma), Au-Ag (108～47 Ma) and AE-dominant (103～45 Ma) deposits, which correspond to volcanic-plutonic-related type, occurred at relatively low temperature (about 200$^{\circ}$ to 35$0^{\circ}C$) and shallow-crustal level (1.0$\pm$0.5 kb) from the ore-forming fluids containing more amounts of less-evolved meteonc waters ($\delta$$^{18}$ $O_{H2O}$;-10～5$\textperthousand$). These characteristics of the Cretaceous precious-metal deposits can be attributed to the complekities in the ore-precipitating mechanisms (mixing, boiling, cooling), suggestive of epi- to mesothermal environments. Therefore, the differences of the emplacement depth between the Daebo and the Bulgugsa igneous activities directly influence the unique temporal and spatial association of the deposit styles.les.

• Applied Biological Chemistry
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• v.39 no.5
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• pp.349-354
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• 1996

The Polyvinyl alcohol(PVA) oxidase involved in PVA degradation by microorganism has been purified to homogeneity from culture broth of Xanthomonas campestris J2Y grown in a minimal medium containing PVA as a sole carbon source. The enzyme was purified by DEAE-cellulose chromatograpy and Sephadex G-150 gel filtration. The purified PVA oxidase was electrophoretically homogeneous both in the absence and presence of SDS. The molecular weight of the enzyme was estimated to be about 55,000 daltons by SDS-polyacrylamide gel electrophoresis and Sephadex G-150 gel filtration. The native enzyme existed as a monomer. The optimal pH and temperature was shown to be pH 7 and $37^{\circ}C$ respectively. The activity of enzyme was stable below $55^{\circ}C$ and between pH range of $5{\sim}11$. The enzyme activity was significantly inhibited by metal compounds such as $Ag^{2+},\;Hg^{2+}$. While, metal ions such as $Mn^{2+},\;and\;Cu^{2+}$ stimulated the reaction. Km value of the enzyme for PVA was $7.04{\times}10^{-2}mmol/{\ell}$.