• 미생물학회지
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• 제38권1호
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• pp.54-56
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• 2002

Induction of laccase isozymes under acidic stresses were determined in Trametes versicolor, Pleurotus ostreatus and Ganoderma lucidum isolated in Korea, and in Lentinus squarrosulrs isolated in Thai. When cultures of these fungi were transferred to acidic liquid media (pH 3.0-4.0), the activities of secreted extralcellular laccases were increased 60% and 400% in T. versicolor and G. lucidum respectively. However, there was no such induction in L. squarrosulus or P. ostreatus. In L. squarrosulus, different laccase isozymes in the electrophoretic mobilities were induced under acidic conditions.

• Journal of Microbiology and Biotechnology
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• 제1권4호
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• pp.274-280
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• 1991

Effects of IPTG induction on cell growth and production of ${\beta}$-galactosidase-preS2 fusion protein (${\beta}$gal-preS2) were studied in a defined medium using a recombinant Escherichia coli JM109/pCMHB30. IPTG was added (0.2 mM) to induce the cloned-gene expression in the early-, mid-, and late-log growth phases. The most serious decreases in growth rate and plasmid stability were observed for the induction in the early-log growth phase. The expression level of ${\beta}$gal-preS2 attained by the induction in the mid-log phase was about 0.51 mg fusion protein/mg total cellular protein, which was 2- and 5-fold improvement over the levels obtained with the inductions in the early- and late-log phases. Formation of acidic byproducts including acetate and pyruvate showed different profiles during the fermentation period for each cases of induction; pyruvate was the major byproduct for the induction in the early-log phase while acetate production became more significant for the cases of inductions in the mid- and late-log phases.

• Applied Biological Chemistry
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• 제36권1호
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• pp.1-6
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• 1993

Chitooligosaccharides 혼합물을 처리한 벼 세포 현탁배양액과 처리하지 않은 배양액의 단백질 및 효소활성을 비교하여 이 elicitor에 의해 유도되는 chitinase를 확인하였다. Chitooligosaccharide 혼합물 처리로 chitinase 활성은 비처리구에 비하여 3.5배 증가하였으며 증가율이 단백질 증가보다 10배 이상 높아 본 효소가 선택적으로 유도되는 것으로 나타났다. Polyacrylamide gel 전기영동상 나타나는 총 11종의 chitinase중 4종이 유도효소로 판명되었으며 DEAE-cellulose chromatography 결과 3개는 $26{\sim}58\;KD$의 분자량을 가진 acidic chitinase 분획에, 나머지 1개는 basic chitinase 분획에 속한 것으로 나타나서 주로 acidic chitinase가 유도되는 것으로 확인되었다.

• 한국가스학회지
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• 제12권4호
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• pp.52-57
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• 2008

본 연구는 pH환경 중에서 고주파 열처리한 강인주철의 마멸 부식거동을 pH환경 중에서의 접촉압력에 따른 마멸부식거동, 침지 부식 후 부식마멸거동 및 전기화학적 부식거동에 대해 고찰하였다. 응축수의 pH가 낮아질수록 마멸부식율은 급격히 증가하고, 전기화학적 양극분극에 의한 강인주철의 부식양상은 중성에서 가늘고 긴 흑연의 편상조직이 나타나지만, 강산성 중에서는 흑연이탈 현상으로 표면이 거칠게 나타난다.

• Bulletin of the Korean Chemical Society
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• 제18권1호
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• pp.18-23
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• 1997

Data from structure/activity studies in vir gene induction system have led to evaluate the working hypothesis of interaction between phenolic inducers and phenol binding proteins. The primary specificity in the association of a phenolic inducer with its receptor in our system is hypothesized to be the hydrogen bonding interactions through the ortho methoxy substituents as well as the proton transfer between the inducer and the binding protein. In this paper the proposed working model for phenol-mediating signal transduction was evaluated in several ways. The importance of the general acid-base catalysis was first addressed by the presence of an acidic residue and a basic residue in the phenol binding protein. Series of compounds were tested for vir gene expression activity to confirm the generation of a strong nucleophile by an acidic residue and an involvement of a basic residue as a proton acceptor. An attempt was made to correlate the pKa values of the phenolic compounds with vir gene induction activities as inducers to further support the proposed proton transfer mechanism. Finally, it was also observed that the regioselectively attached methoxy group on phenol compounds is required as the proper hydrogen bond acceptor.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.94-94
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• 2002

Lactadherin (formerly known as BA46), a major glycoprotein of the human milk fat globule membrane, is abundant in human breast milk and breast carcinomas and may prevent symptomatic rotavirus infections. In this study, under the control of mouse whey acidic protein (WAP) promoter, the expression pattern of lactadherin (Ltd) in lactogenic hormone-dependent mouse mammary epithelial cell line HC11 were tested. pLNWLtd construct containing 2.4 kilobases of the WAP promoter and 1.5 kilobases of human lactadherin gene was stably transfered into HC11 cells using retroviral vector system. Integration and expression level of the transgene was estimated using PCR and RT-PCR, respectively. Prominent induction of Ltd gene under the WAS promoter was accomplished in the presence of insulin, hydrocortisone and prolactin, while induction with insulin alone resulted in lower expression. Our results demonstrate that the expression of the transgene is increased by synergistic effect of several lactogenic hormones, including insulin, hydrocortisone, and prolactin.

• 한국동물학회지
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• 제28권2호
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• pp.108-119
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• 1985

Stress protein (SP) 遺傳子發現의 調節機構를 밝히기 위한 한가지 방편으로 환경의 stress와 pH가 SP의 合成誘導에 어떤 作用을 하는지를 SDS-PAGE를 이용해서 分析하였다. 蛋白質合成의 전반적 양상은 MEF와 SCK 세포에서 달랐으나 SP의 양상은 동일하였다. 그중에서 $SP_70$의 誘導와 感衰의 kinetics는 특히 흥미로웠다. $SP_70$의 kinetics는 酸性 pH와 正常 pH에서 類似하였으나 最大量의 SP 合成에 필요한 溫度와 그 處理時間은 pH에 의해 달리 나타나서, 酸性 pH 에서는 자은 溫度와 짧은 處理時間에서 나타나고 더욱 오래 지속되는 경향을 보였다. SP의 合成誘導와 SP mRNA의 축적은 actinomycin D에 의해 阻止되는 사실로 미루어 SP의 合成이 誘導되기 위해서는 새로운 mRNA의 合成이 필요함을 알수 있었고, cycloheximide 처리의 결과는 SP의 合成誘導에 앞서서 어떤 特異한 蛋白質의 合成은 일어나지는 않음을 알수 있었다. 이상과 같은 몇가지 實驗結果는 MEF와 SCK 세포에서 SP의 合成誘導는 일차적으로 轉寫水潗에서 調節되며, $SP_70$의 合成은 自動調節됨과 아울러 SP의 水潗은 세포늬 stress 상태와 相關關係가 있는 것으로 推論할수 있음을 보여주었다.

• The Korean Journal of Ecology
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• 제17권1호
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• pp.69-78
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• 1994

1991년 3월부터 1993년 6월까지 공단, 준공단 및 비공단지역에서 빗물을 채취하여 pH를 측정하고, 공단과 비공단지역에서 NH4+, NO3-, SO42- 및 전기전도도를 1년동안 측정하였다. 또한 황산과 질산의 1:4로 하여 pH4.6, 3.6 및 2.6으로 조정한 산성강하물이 털깃털이끼의 NRA, 광합성 및 수분포텐셜에 미치는 영향을 조사하였다. 빗물의 pH는 모두 이른 봄에 낮고 여름에 높았으며 공단지역의 낮은 pH는 다량의 이온 특히 SO42-와 관련되었다. 빗물의 SO42-, NO3- 및 NH4+의 월 평균은 공단지역에서 각각 2.94(81.0%), 0.48(13.2%) 및 0.21(5.78%)mg/l 이었고, 비공단지역에서는 각각 0.61(64.21%), 0.25(26.3%) 및 0.9(9.5%)mg/l로 공단지역에서 높았다. 공단지역에서 생육하는 Hypnum plumaeforme의 NRA의 비공단지역에 비하여 공단지역의 것이 낮았고, 산성강하물로 24일 동안 처리한 NRA를 측정한 결과 공통적으로 억제되었다. 공단지역과 비공단지역에서 생육한 식물의 광합성능은 산성강하물 처리후 24일만에 pH3.6에서 각각 85와 80%이상 회복되었으나 pH2.6에서는 66과 56% 회복되었다. 공단과 비공단의 식물체의 수분포텐셜은 산성강하물에 대한 뚜렷한 차이를 보이지 않았으나 단수후 모두 크게 낮아졌다.

• The Korean Journal of Ecology
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• 제15권4호
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• pp.355-363
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• 1992

Nitrate reductase activity(NRA) and induced NRA were compared in 4 species of moss ctenidium molluscum, homalothecium, tortella tortusa and neckera crispa collected from limestone in england. the NRA and dry weight of the c. molluscum were also measured after spraying with acidic deposition adjusted to ph 5.6, 4.6, 3.6 and 2.8 with one of two molar ratios of nitric to sulfuric acid, i.e. 1:0(N alone) and 1:2(1N+2S) for 20 days. All 4 species showed high NR leavels in the upper part of cut shoots and occurred maximum inducation of NRA within 6h. c. molluscum had the highest NRA levels among 4 species. after daily spraying of acidic deposition, NRA of c. molluscum was increased much more largely at ph 6 and ph 3.6 derived from N alone than from 1N+2S. However that was decreased at ph 2.8 derived both from N alone and 1N+2S . Decline of dry weight had occurred at ph 3.6 and 2.8 derived both from N alone and 1N+2S. Whereas substantial fertilization effect was observed at ph 4.6 derived from N alone. the data suggest that c. molluscum are able to utilize nitrate more effectivery than any other species, and NRA induction are more sensitive than growth response to nitrogen content of acidicdeposition in a short- term. however toxic effects was detected at high $NO_3$ supply and low phacidic deposition.

• Oncology Reports
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• 제43권5호
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• pp.1705-1713
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• 2020

In several cancers, the acidic microenvironment of cancer cells has been implicated in enhanced malignancy and metastasis. In the present study, it was observed that gastric cancer cell lines, SNU601 and AGS, exposed to an acidic medium had increased invasiveness, as assessed using Matrigel-coated Transwell analysis. The factors regulating such acidity-mediated enhancement of invasiveness were investigated and it was revealed that a low-pH environment markedly increased kallikrein-related peptidase 7 (KLK7) and kallikrein-related peptidase 8 (KLK8) expression. Gene silencing assays confirmed that these peptidases were involved in acidity-promoted invasion. Acidic conditions also increased the expression of cyclooxygenases (COX), key regulatory enzymes in the catalytic pathway of prostaglandin production. Notably, these enzymes appeared to be involved in the acidity-mediated expression of KLK7 and KLK8, as revealed using COX inhibitors. Therefore, it was indicated that tumor invasion enhancement by extracellular acidity is regulated at least in part through the induction of the COX/KLK7 and KLK8 axis in gastric cancer cells.