• Korean Journal of Microbiology
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• v.28 no.4
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• pp.283-289
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• 1990

The competence time of Streptomyces viridochromogenes for aerial mycelium formation was determined. Within 10 hrs after spore inoculation the submerged mycelium was programed to form aerial mycelium, when the former was laid on agar plate. The white aerial mycelium was formed 17-22 hrs after the transfer. Ascorbic acid oxidizing enzyme band on native gel showed chracteristic mobility change during aerial mycelium formation. Total activity of this enzyme did not show any correlation with the differentiation. The asay condition for the crude enzyme was determined. EDTA and $FeCl_{2}$ showed stimulatory effect. Approximate ratio of oxygen consumed to ascorbic acid oxidized was 1:1.

• Journal of Korean Society on Water Environment
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• v.31 no.4
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• pp.399-406
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• 2015

A sequencing batch reactor was operated under different pH conditions to see the influence of free ammonia (FA) and free nitrous acid (FNA) to microbial community on ammonium partial nitrification. Long-term influences of FA and FNA were evaluated by polymerase chain reaction-denaturing gradient gel electrophoresis and fluorescence in situ hybridization. Nitrite accumulation was successfully achieved at pH 8.2 and 6.3. The shifts in the microbial community were observed when influent ammonia concentration increased to 1 g $NH_4$-N/L at pH 8.2, and then when pH was dropped to 6.3. Both Nitrosomonas and Nitrosospira were selected during the startup of the reactor, and eventually became dominant members as ammonia-oxidizing bacteria. The results of molecular microbiological analysis strongly suggested that the composition of microbial community was changed according to the method used to control nitrite-oxidizing bacteria.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.4
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• pp.211-216
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• 2008

TREK (TWIK-RElated $K^+$ channels) and TRAAK (TWIK-Related Arachidonic acid Activated $K^+$ channels) were expressed in COS-7 cells, and the channel activities were recorded from inside-out membrane patches using holding potential of - 40 mV in symmetrical 150 mM $K^+$ solution. Intracellular application of an oxidizing agent, 5,5'-dithio-bis (2-nitrobenzoic acid) (DTNB), markedly decreased the activity of the TREK2, and the activity was partially reversed by the reducing agent, dithiothreitol (DTT). In order to examine the possibility that the target sites for the oxidizing agents might be located in the C-terminus of TREK2, two chimeras were constructed: TREK2 (1-383)/TASK3C and TREK2 (1-353)/TASK3C. The channel activity in the TREK2 (1-383)/TASK3C chimera was still inhibited by DTNB, but not in the TREK2 (1-353)/TASK3C chimera. These results indicate that TREK2 is inhibited by oxidation, and that the target site for oxidation is located between the amino acid residues 353 and 383 in the C-terminus of the TREK2 protein.

• Journal of the Korean Wood Science and Technology
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• v.16 no.3
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• pp.5-16
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• 1988

This experiment was executed to investigate the effect of activation of veneer surface by oxidizing agents, hydrogen peroxide and nitric acid, on bonding characteristics of Malas(Homalium foetidum Benth) plywood, in which the effects of these oxidizing agents amount, pretreatment time, and pressing time and temperatue on shear strength of the plywood were examined and discussed. In this research the activation of veneer surface by oxidants was effective in raising shear strength but the difference in shear strength was not observed between hydrogen peroxide and nitric acid treatment. Hydrogen peroxide treatment, however, seemed to be more profitable to industrial application because of its lower concentration and easier handling than nitric acid. The bonding method by lignin-phenol adhesive through surface activation revealed inferior shear strength to phenol- and urea-formaldehyde adhesive but superior water resistance to urea-formaldehyde adhesive and this bonding method, in addition, have the advantage of lower cost compared with phenol-formaldehyde adhesive, Therefore, this bonding method by lignin-phenol adhesive through surface activation seemed to economical in manufacturing of water-resistant wood panel materials in future.

• Korean Journal of Microbiology
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• v.26 no.4
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• pp.324-331
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• 1988

Ascorbate oxidizing enzyme from the crude extract of Pleurotus ostreatus was purified by ammonium sulfate precipitation, preparative polyacrylamide gel electrophoresis, DEAE Sepharose CL-6B ion exchange chromatography and Sephadex G-150 gel filtration chromatography. The molecular weight of the enzyme estimated by Sephadex G-150 gel filtration chromatography was 140,000 and that of its subunit by SDS-polyacrylamide gel electrophoresis 66,000. The optimum pH for the maximum activity of the enzyme was 5.2 and the isoelectric point of the enzyme was 6.0 Km values for L-ascorbic acid and D-isoascorbic acid were both 2.2.$\mu$M, which indicates that the enzyme has the asme affinity towards both substrates.

• Microbiology and Biotechnology Letters
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• v.22 no.6
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• pp.672-678
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• 1994

For production of vanillic acid from vanillin, optimum culture conditions for Pseudomo- nas sp. GD-088, having vanillin-oxidizing activity were investigated. The highest vanillin-oxidizing activity was obtained when this strain was cultured at 30$\circ$C for 24 hr in a medium consisting of 3.0 g/l xylose and 0.46 g/l NH$_{4}$CI (pH 7.0). When 18 g/l of whole Pseudomonas sp. GD-088 cells as the enzyme source was used in 50 mM phosphate buffer (pH 7.0) containing 3.0 g/l of vanillin, 2.463 g/l of vanillic acid was produced for 40 minutes. This amount of vanillic acid corresponds to a 90% yield, based on vanillin.

• Food Science and Preservation
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• v.9 no.2
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• pp.240-247
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• 2002

This study, to enhance the sterilization, browning inhibition and precooling effect of electrolyzed oxidizing water(EOW) as cleaning water on food industry, was carried out to investigate the efficacy of electrolyzed oxidizing water(EOW) with 0.85% NaCl, 0.5% ethanol, polysorbate 80 of 1 ppm, 0.5% lemon juice and 0.5% citron juice. Escherichia coli KCTC 1039 with initial count of 5.63$\times$10$\^$8/ CFU/mL were reduced to <10$^1$CFU/mL after 15∼30 sec when it was treated by electrolyzed oxidizing water added with various food additives. Bacillus cereus KCTC 1012 were reduced to <10$^1$ CFU/mL after 2 minutes treatment with electrolyzed oxidizing water containing polysorbate 80 and ethanol. Iactobacillus plantarum KCTC 3108 were reduced to <10$^1$CFU/mL after 30 sec treatment with electrolyzed oxidizing water containing polysorbate 80, citron juice and lemon juice, respectively. Erwinia carotovora subsp. carotovora KCTC 2776 were reduced to <10$^1$CFU/mL after 30 sec treatment with electrolyzed oxidizing water containing polysorbate 80 and lemon juice. Browning inhibition effect was determined by comparison of polyphenol oxidase activity. Inhibition ratio of polyphenol oxidase was approximately 62∼84% in most treatments with the exception of 57% and 25% inhibition by 0.5% ascorbic acid and polysorbate 80, respectively. Sliced potato dipped in electrolyzed oxidizing water containing NaCl and citron juice for 30 minutes showed significantly low PPO activity, 64 units in treatment with NaCl and 91 units in treatment with citron juice. At the same time, changes in color value(△E) of sliced potato was below 3 in most treatments.

• Journal of Environmental Health Sciences
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• v.8 no.2
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• pp.33-46
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• 1982

This experiment was carried out for the purpose of reducing alkaloid in reconstituted tobacco sheet and effluent of reconstituted tobacco sheet manufacturing company by treating oxidizing agents such as ozone, sodium hypochlorite, perchloric acid and hydrogen peroxide to tobacco extract created from the manufacturing process of reconstituted tobacco sheet. The effect of alkaloid reduction in tobacco extract by the volume added, time of treatment and pH of oxidizing agents were as follows: 1. When the solid rate of tobacco extract stood at 10 percent, the content of alkaloid, total sugar, total nitrogen and chlorine was 1,600mg/l, 11,000mg/l, 3,200mg/l and 4,000mg/l, respectively. 2. The effect of alkaloid reduction through ozone treatment was in proportion to time of ozone treatment. Alkaloid showed a 31.2 percent reduction under 8 hours' ozone treatment and 0.23g ozone consumed to remove lmg alkaloid. 3. Alkaloid reduction through sodium hypochlorite treatment was influenced by quantity of chlorine in sodium hypochlorite solution. To remove lmg alkaloid, 36.3mg chlorine was used. Reduction of alkaloid was not affected by time of sodium hypochlorite treatment, while showed the best reaction under pH 5-7. 4. The effect of alkaloid reduction by perchloric acid was under the control of the volume added and time of treatment of perchloric acid. The volume of perchloric acid required to remove alkaloid was on the decrease as time of treatment was getting longer. lmg alkaloid was removed by 0.15g perchloric acid under 8 hours' perchloric acid treatment. 5. Alkaloid reduction reacted slowly to the volume added and time of treatment of hydrogen peroxide. Under 8 hours' hydrogen peroxide treatment, it showed maximum removal, registering 10 percent alkaloid reduction.

• Journal of Microbiology and Biotechnology
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• v.17 no.5
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• pp.812-821
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• 2007

The ecosystems of certain abandoned mines contain arsenic-resistant bacteria capable of performing detoxification when an ars gene is present in the bacterial genome. The ars gene has already been isolated from Pseudomonas putida and identified as a member of the membrane transport regulatory deoxyribonucleic acid family. The arsenite-oxidizing bacterial strains isolated in the present study were found to grow in the presence of 66.7 mM sodium arsenate($V;\;Na_2HAsO_4{\cdot}7H_2O$), yet experienced inhibited growth when the sodium arsenite($III;\;NaAsO_2$) concentration was higher than 26 mM. Batch experiment results showed that Pseudomonas putida strain OS-5 completely oxidized 1 mM of As(III) to As(V) within 35 h. An arsB gene encoding a membrane transport regulatory protein was observed in arsenite-oxidizing Pseudomonas putida strain OS-5, whereas arsB, arsH, and arrA were detected in strain OS-19, arsD and arsB were isolated from strain RW-18, and arsR, arsD, and arsB were found in E. coli strain OS-80. The leader gene of arsR, -arsD, was observed in a weak acid position. Thus, for bacteria exposed to weak acidity, the ars system may cause changes to the ecosystems of As-contaminated mines. Accordingly, the present results suggest that arsR, arsD, arsAB, arsA, arsB, arsC, arsH, arrA, arrB, aoxA, aoxB, aoxC, aoxD, aroA, and aroB may be useful for arsenite-oxidizing bacteria in abandoned arsenic-contaminated mines.

• Applied Chemistry for Engineering
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• v.8 no.2
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• pp.179-190
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• 1997

To study the effects of chemical composition on the fusion temperatures of coal ashes, the chemical composition, mineral matter, and fusion temperature were studied with 54 kinds of coal ash samples including Korean anthracite coals. CaO, MgO and $Fe_2O_3$ were observed to be major fluxing elements in reducing and oxidizing atmosphere. The fluxing effect of $Fe_2O_3$ was increased more in reducing atmosphere. In a base/acid ratio, the fusion temperature decreased with increasing amounts of basic components. Nevertheless, the correlation between a fusion temperature and base/acid ratio was not shown well in a higher ratio of $Fe_2O_3/CaO$. The differences of fusion temperatures between oxidizing and reducing atmosphere showed close relationship with $SiO_2/Al_2O_3$ ratio rather than with $Fe_2O_3$ contents. Multiple regression was used to predict the fusion temperature of coal ashes, and it was established that the major predictors in oxidizing atmosphere were Base/Acid, $Fe_2O_3/CaO$, $SiO_2/Al_2O_3$, and $(SiO_2/A1_2O_3){\cdot}(Base/Acid)$ and Base/Acid, $Fe_2O_3/CaO$, $SiO_2$, and $TiO_2$ were major ones in reducing atmosphere.