• Applied Biological Chemistry
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• v.38 no.2
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• pp.118-122
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• 1995

Escherichia Coli ornithine transcarbamylase is the enzyme which catalyzes the L-citrulline biosynthesis from L-ornithine and carbamyl phosphate. To facilitate the purification of enzyme which will be used for many biochemical studies such as structure and function relationships and catalytic mechanisms, the cloning and expression of E. coli argI gene for ornithine transcarbamylase was conducted. argI was amplified from genomic DNA of E. coli strain of $DH5{\alpha}$, by polymerization chain reaction (PCR) method. The amplified argI gene was ligated to the prokaryotic expression vector pKK223-3 and used for transformation of E. coli TB2 which was deficient of ornithine transcarbamylase. The over-produced enzyme by the tnansformant was purified by ammonium sulfate fractionation, heat denaturation and affinity chromatography. The result of SDS denaturation gel electrophoresis for the purified enzyme showed a single band of about 38 kDa of ornithine transcarbamylase. Kinetic data for the expressed enzyme gave almost the s?????? values as those of the wild type enzyme. The $k_{cat}$, of the enzyme was $1.0{\times}10^5min^{-1}$, and $K_ms$ for ornithine and carbamyl phosphate were 0.35 mM and 0.06 mM, respectively.

• Korean Journal of Environmental Biology
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• v.30 no.3
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• pp.219-230
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• 2012

We surveyed 23 sites of Jinhae Bay in spring and summer 2010 in order to study the correlation between the variation of environmental factors, including salinity, temperature, and nutrients and the characteristics of phytoplankton community structures in summer stratification. Phytoplankton biomass was high in the surface water in summer; however, it was very low in the bottom water. The results showed a negative correlation between chlorophyll a (chl. a) and nutrients (silicate, nitrate, nitrite, ammonium, and phosphate) or nutrients ratio in summer; however, there was mostly a positive correlation between chl. a and these nutrients in spring. This inconsistent correlation between spring and summer was attributed to the phytoplankton community, because a diverse phytoplankton community has different nutrient uptake abilities. In addition, the results of CCA (canonical correspondence analysis) showed a negative correlation between phosphate and dominant species, including Chaetoceros spp., Skeletonema costatum-like spp., and Pseudo-nitzschia delicatissima in summer, but a strong positive correlation between DIN (dissolved inorganic nitrogen) and the dominant species, including Cryptomonas spp. and Pseudo-nitzschia multistriata in spring. Consistently, the dominant algal species in summer showed a relatively smaller size cells compared with those in spring, suggested that it may have related with the low nutrient levels at surface layer due to strong stratified water column of summer.

• Journal of the Korean Chemical Society
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• v.33 no.5
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• pp.484-495
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• 1989

Reactions of $(Et_4N)_2[MoOCl_5]$ with multidentate ligands containing nitrogen or/and oxygen donor atom (EDTA, DTPA, IDA, CyDTA, OX) produce a series of binuclear molybdate (V) complexes. The prepared Mo (V) complexes has been identified by Elemental Analysis, Infrared Spectra, Proton Magnetic Resonance Spectra, and Electronic Spectra. The electrochemical reduction mechanism has been studied by Cyclic voltammetry, Controlled Potential Coulometry, and Spectrophotometry in pH 3.571-10.375 acetate, borate, phosphate/sodium hydroxide, phosphate, ammonium/ammonia buffers. The cyclic voltammogram of the Mo-EDTA, DTPA, IDA, CyDTA complexes at pH < ca. 6.00 have shown two reduction waves. The first reduction wave shows two electron process and the second reduction wave shows two electron process. The cyclic voltammogram of the Mo-EDTA, DTPA, IDA, CyDTA complexes at pH < ca. 8.00 has shown one reduction wave. This reduction wave show four electron process. The cyclic voltammogram of the Mo-OX complex at pH < ca. 7.2 has shown one reduction wave. This reduction wave show four electron process.

• Mycobiology
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• v.36 no.1
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• pp.34-39
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• 2008

Schizophyllum commune is an edible and medicinal mushroom widely distributed in the world. The optimal growth conditions for the mycelia of 10 strains of the fungus were investigated. The temperature suitable for the mycelial growth and density was obtained at $30{\sim}35^{\circ}C$. Among the tested conditions, the minimum mycelial growth was found at $15^{\circ}C$. In case of pH, the most favorable growth was found at pH 5. The results indicated that this mushroom well adapted to high temperature and low pH for its mycelial growth. Considering growth phenotype of mycelia, Hamada, Hennerberg, PDA and YM were the most suitable and Lilly, Glucose triptone, Glucose peptone and Hoppkins were the most unfavorable among tested media for the mycelial growth of S. commune. Out of tested carbon sources, dextrin and fructose were the most suitable and lactose, mannose and sorbitol were the unsuitable for the fungus. Compact mycelial density was obtained from most of the carbon sources. Among used nitrogen sources, calcium nitrate, potassium nitrate and alanine were the most appropriate and the most incompatible were ammonium phosphate, histidine, urea and arginine for mycelial growth of S. commune on the culture media. Calcium nitrate, histidine and potassium nitrate showed moderately thin or thin, and rest of nitrogen sources showed compact or moderately compact mycelial density.

• Mycobiology
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• v.38 no.1
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• pp.17-25
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• 2010

The common split-gilled mushroom, Schizophyllum commune is found throughout the world on woody plants. This study was initiated to evaluate conditions for favorable vegetative growth and to determine molecular phylogenetic relationship in twelve different strains of S. commune. A suitable temperature for mycelial growth was obtained at $30^{\circ}C$. This mushroom grew well in acidic conditions and pH 5 was the most favorable. Hamada, glucose peptone, Hennerberg, potato dextrose agar and yeast malt extract were favorable media for growing mycelia, while Lilly and glucose tryptone were unfavorable. Dextrin was the best and lactose was the less effective carbon source. The most suitable nitrogen sources were calcium nitrate, glycine, and potassium nitrate, whereas ammonium phosphate and histidine were the least effective for the mycelial growth of S. commune. The genetic diversity of each strain was investigated in order to identify them. The internal transcribed spacer (ITS) regions of rDNA were amplified using PCR. The size of the ITS1 and ITS2 regions of rDNA from the different strains varied from 129 to 143 bp and 241 to 243 bp, respectively. The sequence of ITS1 was more variable than that of ITS2, while the 5.8S sequences were identical. A phylogenetic tree of the ITS region sequences indicated that the selected strains were classified into three clusters. The reciprocal homologies of the ITS region sequences ranged from 99 to 100%. The strains were also analyzed by random amplification of polymorphic DNA (RAPD) with 20 arbitrary primers. Twelve primers efficiently amplified the genomic DNA. The number of amplified bands varied depending on the primers used or the strains tested. The average number of polymorphic bands observed per primer was 4.5. The size of polymorphic fragments was obtained in the range of 0.2 to 2.3 kb. These results indicate that the RAPD technique is well suited for detecting the genetic diversity in the S. commune strains tested.

• Journal of the Korean Society of Safety
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• v.32 no.5
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• pp.149-156
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• 2017

This study investigates fire-retardant performances and combustion/thermal characteristics of fire-retardant treated wood by comparing them with those of fire-retardant untreated wood from the expreimental resutls of cone calorimeter and thermo-gravimetric(TG) analyzer. Hazardousness of combustion product gases for fire-retardant treated wood and untreasted wood were also observed from the results of internal finish material incombustibility test according to the Korea standard code of KS F 2271. In this study, we also tried to improve the fire retardant performance of wood by applying fire-retardant chemical composites, and to secure the fire safety performance in buildings. Red pine (Pinus densiflora) was selected as a test specimen because it is mostly used as a building material in Korea. Fire retardant chemical composites (FRCs) were prepared by mixing boron, phosphorous, and nitrogen species and treated by press-impregnation method. Water-based FRCs were composed of 3% boric acid($H_3BO_3$), 3% borax decahydrate($Na_2B_4O_7$), 8% ammonium carbonate($(NH_4)_2CO_3$), diammonium phosphate ($(NH_4)_2HPO_4$) varied from 10-30% and potassium carbonate($K_2CO_3$) varied from 10-30%. From the test results of cone calorimeter, TG analysis and gas hazard assessments, newly proposed were the optimal composition and production methods of FRCs which can sufficiently meet fire-retardant level 3 based on Korea law of construction. Thus, the FRCs, developed in this study, are anticipated to contribute to the improvement of fire safety and widespread of usage in wood as building materials.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.2 no.2
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• pp.99-108
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• 1998

Results obtained from this research showed that the anaerobic contact process was applicable to pear waste with COD removal efficiencies of up to $95\%$ depending on conditions, provided ammonium and phosphate salts were added as well as other nutrients, present in the commercial fertilizer, Milorganite or in yeast extract. These latter materials were required in minimum concentrations of 5 and 1.5 g/L, respectively, in the feed independent of HRT and volatile solids loading rate, with part of the effect due to the mineral fraction. Digestion was satisfactory over the whole range of volatile solids loading rates and liquid retention time of 30 to 0.5 days tested, although treatment efficiency dropped off noticeably between 1 and 0.5 day liquid retention time because of poorer flocculation and separation of anaerobic bacteria. Settling of anaerobic bacteria including methane producing bacteria was related to settling of mixed liquor suspended solids only at 1 to 5 days liquid retention times, at other liquid retention times anaerobic microorganism settled markedly less efficiently than mixed liquor suspended solids. Further studies are being made to provide information of practical and basic interest. Data on the composition of the active fraction of yeast extract might solve many practical nutrient problems encountered with the anaerobic contact process and improve its economics. Further improvement in the flocculation and settling of anaerobic bacteria as well as other bacteria would improve overall performance and allow the use of shorter liquid retention times with dilute waste. Knowledge about the numbers of methane formers present would allow a degree of understanding and control of the process not presently attainable.

• Journal of Pharmaceutical Investigation
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• v.35 no.6
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• pp.431-436
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• 2005

A high-performance liquid chromatographic method was validated for quantitation of nadolol in human plasma. Nadolol and internal standard, pindolol, were extracted with tert-butyl methyl ether after addition of 10 M sodium hydroxide solution. The analytes were separated on a reverse phased C18 column using a mobile phase consisting of 0.05 M ammonium phosphate monobasic buffer, acetonitrile and methanol (81: 17:2 v/v/v) and detected using a fluorescence detector (excitation wavelength 230 nm, emission wavelength 294 nm). The method was specific and sensitive enough to detect as low as 3 ng/mL of nadolol in human plasma. Linear calibration range was 3-150 ng/mL with correlation coefficient greater than 0.999. The overall accuracy was in the range of 96.8 to 103% and precision C.V.(%) 7.30 to 12.2%. The recovery was approximately 100% and stability was confirmed during storage and sample preparation. The present HPLC method was successfully applied to study bioavailability after oral administration of 80 mg of nadolol in healthy Korean subjects. The mean $AUC_{t}$ was $1968{\pm}397\;ng{\cdot}hr/mL$ and $C_{max}$ of $186{\pm}79.3\;ng/mL$ was reached at $3.5{\pm}0.76\;hr$. The mean $t_{1/2}$ of nadolol was $17.3{\pm}2.59\;hr$.

• Journal of the Korean Wood Science and Technology
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• v.12 no.2
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• pp.3-9
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• 1984

This study was carried out to examine the practicality of DAP[$(NH_4)_2HPO_4$] as fire retardant for plywood by static bending test the redried plywoods which had been soaked in 20% $(NH_4)_2HPO_4$ solution. Being hot/cold soaked in the solution for 3/3, 6/3, 9/3 and 12/3 hours and redried by cyclic press-drying method at the platen temp. of 130, 145, 100 and $175^{\circ}C$, the treated plywoods were tested to offer the mechanical data, that is, $S_{pl}$(stress at proportional limit), MOE(modulus of elasticity), MOR(modulus of rupture) and $W_{pl}$(work per unit volume to proportional limit ) in flexure. The results obtained were summarized as follows. 1. $S_{pl}$ of fire retardant treated plywoods ("FRP" would be used hereinafter) decreased as the platen temperature increased, but it was superior to that of non-treated plywoods(Control) at $160^{\circ}C$ or higher. 2. MOE of FRP decreased roughly with the increase of temperature, hut this tendency was not constant. And the value of FRP was higher than that of Control even at $175^{\circ}C$. 3. MOR of FRP showed same temperature-dependent tendency as MOE, but it was influenced more sensitively at the higher temperature. 4. $W_{pl}$ of FRP also decreased gradually with the increase of platen temperature and the value in DAP 9/3 treatment was Jess than 70% of control plywoods. 5. In view of redrying time and mechanical properties, the most reasonable platen temperature for DAP treated FRP was $160^{\circ}C$ in this study.

• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.2
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• pp.1-9
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• 1996

The possibility of using waste brine and cabbage waste from kimchi industry as raw materials for the production of yeast cell mass was investigated. Among four strains of osmotolerant yeast, Candida guilliermondii ATCC 6260 showed the best growth in the waste brine containing about 1.0g/L of reducing sugar and 7% to 12% of NaCl. The growth of C. guilliermondii in waste brine was affected slightly between the temperature range of $25^{\circ}C$ to $35^{\circ}C$ and the initial pH of 3 to 6. The NaCl concentration up to 9% was not inhibitory to the growth of C. guilliermondii and the addition of 10mM of ammonium salts or 5mM of potassium phosphate had no effect on the growth. The growth of yeast reduced BOD of the waste brine by 85% within 24hours. When C. guilliermondii was cultured in waste brine added with cabbage juice extracted from waste cabbage, the cell mass was increased significantly.