• 미생물학회지
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• 제28권4호
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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.

• 한국물환경학회지
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• 제31권4호
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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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• 제12권4호
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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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• 제16권3호
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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.

• 미생물학회지
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• 제26권4호
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• pp.324-331
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• 1988

Pleuratus ostreatus로부터 ascorbate oxidizing enzyme을 황산암모늄 침전, preparative polyacrylamide gel 전기영동, DEAE Sepharose CL-6B 이온교환크로마토그라피, Sephadex G-150 gel 여과크로마토그라피의 단계를 거쳐 순수분리 하였다. 이 효소의 분자량은 gel 여과크로마토그라피에 의하여 140,000 정도로, 효소의 소단위 분자량은 SDS-polyacrylamide gel 전기영동에 의하여 66,000 정도로 추정되었다. Isoelectric focusing에 의하여 이 효소는 6.0의 등전점을 갖는 것으로 밝혀졌고, 최적반응온도는 $85^{\circ}C$ 정도, 최적반응 pH는 5.2 정도인 것으로 나타났다. 본 효소는 L-ascorbic acid와 D-isoascorbic acid에 대하여 동일한 친화도를 갖는 것으로 보이며, Km값은 두가지 기질에 대해 모두 2.2µM 이였다.

• 한국미생물·생명공학회지
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• 제22권6호
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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.

• 한국식품저장유통학회지
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• 제9권2호
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• pp.240-247
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• 2002

세정수로서의 전해산화수 효능을 증대시키기 위하여 다양한 식품첨가제를 첨가하여 제조한 $0^{\circ}C$ 이하의 세정수에 대한 냉각특성, 살균 및 갈변억제 효과를 조사하였다. 식품첨가제의 첨가비율은 NaCl 0.85%(w/v), ethanol 0.5%(v/v), 레몬과즙 0.5%(v/v), 유자과즙 0.5%(v/v), polysorbate 80은 1 ppm으로 결정하였다. 미생물 사멸효과는 초기 5.63$\times$$10^{ 8}$ CFU/mL인 Escherichia coli KCTC 1039가 모든 첨가구에서15~30초 이내에 전부 사멸하였으며, Bacillus cereu KCTC 1012는 polysorbate 80 및 ethanol 첨가구에서 2분 후, Lactobacillus plantarum KCTC 3108은 polysorbate 80, 유자 및 레몬과즙 첨가구에서 30초만에, 그리고 Erwinia carotovorasubsp. carotovora KCTC 2776은 polysorbate 80 및 레몬과즙 첨가구에서 30초만에 사멸하는 효과를 나타내었다. 갈변억제효과는 polyphenol oxidase의 활성을 측정하여 비교한 결과, asnrbic acid 0.5% 첨가구에 5분간 침지하였을 때 57%의 활성저해를 보인 반면, 25%의 저해능을 보인 polysorbate 80 첨가구를 제외한 모든 처리구에서 62~84%의 높은 활성저해 효과를 보였으며, 그 중에서도 NaCl 및 유자과즙 첨가구에서 30분 침지시에 각각 64, 91 units로 가장 낮은 활성을 보여주었다. 절단 감자를 30분간 침지처리한 후의 색도에서도 대부분의 처리구에서 색차($\Delta$E)가 3 이하를 나타내었다.다.

• 한국환경보건학회지
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• 제8권2호
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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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• 제17권5호
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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.

• 공업화학
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• 제8권2호
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• pp.179-190
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• 1997

준역청탄, 유연탄, 무연탄 및 국내 무연탄을 포함하는 54종의 석탄회분을 대상으로 화학조성 및 광물분석 그리고 용융온도를 측정하여 화학조성이 용융온도에 미치는 영향을 고찰하였다. 석탄회의 구성 산화물중 CaO와 MgO, 그리고 $Fe_2O_3$가 용융온도를 낮추는 산화물임을 알 수 있었다. $Fe_2O_3$에 의한 용융온도 감소 효과는 환원성분위기에서 증가되었다. 산-염기도에서 염기성분의 함량이 증가할수록 용융온도는 감소하였다. 그러나 산-염기도와 용융온도와의 상관관계는 $Fe_2O_3$/CaO비가 증가함에 따라 낮아졌다. 산화성분위기보다는 환원성분위기에서 용융온도가 낮았으며 이때 분위기 변화에 따른 용융온도차는 $Fe_2O_3$의 함량보다는 $SiO_2/Al_2O_3$비와 밀접한 상관성을 보여주었다. 석탄회의 용융온도(연화)를 예측하기 위한 다중회귀분석결과 산화성분위기에서는 Base/Acid, $Fe_2O_3$/CaO, $SiO_2/Al_2O_3$, $(SiO_2/Al_2O_3){\cdot}(Base/Acid)$ 그리고 환원성분위기에서는 Base/Acid, $Fe_2O_3$/CaO, $SiO_2$, $TiO_2$등을 독립변수로 사용함으로써 비교적 상관성이 높은 관계식을 얻을 수 있었다.