• 한국환경성돌연변이발암원학회지
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• 제22권3호
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• pp.169-174
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• 2002

Resveratrol is known to have potent cancer chemopreventive activity against tumorigenesis caused by 7,12-dimetylbenz［$\alpha$］anthracene(DMBA) which is known to be oxidized to reactive products by cytochrome P450 1B1 (CYP1B1). The effects of resveratrol on the activity of recombinant human P450 1 family enzymes, expressed in Escherichia coli membranes with human NADPH-P450 reductase, were determined by measuring alkoxyresorufin O-dealkylation activity, e.g., ethoxyresorufin O-deethylation (EROD) CYP1A1, methoxyresorufin O-demethylation (MROD), CYP1A2, benzyloxyresorufin-O-debenzylation (BROD), CTP1B1. Resveratrol inhibited CYP1B1 and CYP1A1 activities in a dose-dependent manner with $IC_{50}$/ values of 59 and 10$\mu$M for EROD activity and 1.8 and 30$\mu$M for BROD activity, respectively. Resveratrol had only weak inhibitory effect on CYP1A2 activity ($IC_{50}$/ values of 0.44 mM for EROD and ＞2 mM for MROD). Furthermore, resveratrol did not affect NADPH-P450 reductase activity significantly. Resveratrol inhibited the CYP1B1-dependent EROD activity with a $K_{i}$ of 28 $\mu$M in a non-competitive type manner. these results suggest that resveratrol-derived inhibited of CYP1B1 and CYP1A1 activities may contribute to the suppression of DMBA inducible tumorigenesis observed in extrahepatic tissues.s.

• 분석과학
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• 제28권2호
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• pp.132-138
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• 2015

Rosiglitazone metabolites in rat plasma were analyzed after intraperitoneal and oral administration to rats. Seven metabolites (M1-M7) were detected in rat plasma (IP and PO), and the structures were confirmed using liquid chromatography-triple time of flight (TOF) mass spectrometry; as a result, the most abundant metabolite was M5, a de-methylated rosiglitazone. Other minor in vivo metabolites were driven from monooxygenation and demethylation (M2), thiazolidinedione ring-opening (M1, M3), mono-oxygenation (M4, M7), and mono-oxygenation followed by sulfation (M6). Among them, M1 was found to be a 3-{p-[2-(N-methyl-N-2-pyridylamino)ethoxy]phenyl}-2-(methylsulfinyl)propionamide, which is a novel metabolite of rosiglitazone. There was no significant difference in the metabolic profiles resulting from the two administrations. The findings of this study provide the first comparison of circulating metabolite profiles of rosiglitazone in rat after IP and PO administration and a novel metabolite of rosiglitazone in rat plasma.

• 한국식품과학회지
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• 제18권5호
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• pp.364-371
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• 1986

High-ester pectin을 HCI 단독 또는 HCI 과 $NH_4OH$를 병용하여 demethylation 시킨뒤 얻어진 low-ester pectin(LM pectin)으로 gel을 제조하였다. LM pectin gel의 단단함과 강도(强度)를 측정한 결과 HCI로 처리된 LM pectin gel은 일반적으로 강도(强度)가 약하고 거칠며 탄력이 없었다. 반면 $HCl-NH_4OH$로 처리한 LM pectin gel은 텍스쳐가 부드럽고 탄력이 좋았다. 물리적 성질에 대한 LM pectin의 화학적 조성의 상관 관계에서 단단함(Sag값)에 대한 ester함량 및 분자량, 그리고 강도(强度)(puncture stress)에 대한 amide 및 ester함량 EH는 분자량 간에는 유의성 있는 관계가 밝혀졌다. 상관성이 높은 화학적 인자에서 LM pectin gel의 물리적 성질을 예측할 수 있는 관계식을 산출하였다.

• The Plant Pathology Journal
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• 제33권2호
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• pp.193-205
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• 2017

Histone methylation plays important roles in regulating chromatin dynamics and transcription in eukaryotes. Implication of histone modifications in fungal pathogenesis is, however, beginning to emerge. Here, we report identification and functional analysis of a putative JmjC-domain-containing histone demethylase in Magnaporthe oryzae. Through bioinformatics analysis, we identified seven genes, which encode putative histone demethylases containing JmjC domain. Deletion of one gene, MoJMJ1, belonging to JARID group, resulted in defects in vegetative growth, asexual reproduction, appressorium formation as well as invasive growth in the fungus. Western blot analysis showed that global H3K4me3 level increased in the deletion mutant, compared to wild-type strain, indicating histone demethylase activity of MoJMJ1. Introduction of MoJMJ1 gene into ${\Delta}Mojmj1$ restored defects in pre-penetration developments including appressorium formation, indicating the importance of histone demethylation through MoJMJ1 during infection-specific morphogenesis. However, defects in penetration and invasive growth were not complemented. We discuss such incomplete complementation in detail here. Our work on MoJMJ1 provides insights into H3K4me3-mediated regulation of infection-specific development in the plant pathogenic fungus.

• 한국발생생물학회지:발생과생식
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• 제14권4호
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• pp.253-259
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• 2010

DNA 메틸화 (DNA methylation)는 유전자의 발현을 조절하는 대표적인 후생학적 조절기작 (epigenetic regulation) 중에 하나이다. DNA 메틸화 양상은 생식세포 형성과정 및 배 발생단계에서 탈메틸화 (demethylation)와 de novo 메틸화의 드라마틱한 변화가 일어난다. 또한 이러한 DNA 메틸화는 배아줄기세포 (embryonic stem cells, ESCs)에서 특징적인 양상을 보이는 것으로 알려져 있다. 본 연구에서는 생쥐 수정란 유래 배아줄기세포와 체세포핵이식 배아줄기세포 (nuclear transplanted ESCs)를 이용해서 대표적 각인유전자 (imprinting genes)로 알려진 Snrpn, Igf2r, H19 유전자들에 대한 메틸화 양상을 알아보고자 하였다. 연구 결과 H19 유전자에 대해서는 DNA 메틸화 양상은 수정란 유래 배아줄기세포와 체세포핵이식 배아줄기세포에서 비슷한 경향을 보였으나, Snrpn과 Igf2r의 경우에는 체세포핵이식 배아줄기세포에서 과메틸화 (hypermethylation) 경향을 보였다.

• 한국동물생명공학회지
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• 제35권2호
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• pp.163-170
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• 2020

Partheno Embryo's research is known to play a very important role in identifying the development of embryonic cells or analyzing the genetic mechanisms of embryonic development, but the information on apoptosis formed during the early stage of development on Partheno Embryo is very little. Therefore, this study analyzed whether the embryonic cell death of unit embryos can be inhibited by adding Scriptaid, one of HDACi, which plays a role in demethylation of histone proteins as a method of regulating the cell cycle in the early embryo development of Partheno Embryo. As a result, the differentiation rate was higher in the group that added Scriptaid and FBS, but the cellular development was higher in the group that added pregnant serum to Scriptaid. As a result of analyzing the expression of the gene through IF and PCR, the group with the addition of gestational serum increased the expression of BCL2 and PCNA, which affects the anti-Casp3 action in cell survival. In addition, it is interpreted that treatment of Scriptaid for 16 hours, rather than 24 h treatment lowers the expression of Casp-3, a representative factor of apoptosis, and also increases embryonic development, thus affecting early embryo development. Therefore, it is concluded that the 16-hour treatment of Scriptaid and the use of gestational serum will inhibit cell death in the early embryonic development and increase the development rate of the embryo.

• 대한약리학회지
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• 제26권1호
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• pp.83-90
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• 1990

Cimetidine이 theophylline의 약동학적 특성과 대사과정에 미치는 효과를 검토코자 6마리의 개를 대상으로 일주일간 정맥내 cimetidine(30mg/kg/day)투여 전후에 단일 용량의 정맥투여에 따른 theophylline의 약동학적 parameter 및 뇨중 theophylline 대사물 배설의 변화를 교차 실험을 통하여 관찰하였다. 대조실험에 비해 cimetidine투여후 theophylline의 청소율은 평균 31%(P<0.05)감소하였고 혈장반감기는 29%(P<0.01)연장되었다. 그러나 steady-state의 분포용적 및 혈장 단백 결합의 변화는 관찰할 수 없었다. Theophylline의 주 대사물인 3-methylxanthine, 1-methyluric acid 및 1,3-dimethyluric acid의 24시간 뇨증 배설량은 cimetidine투여후 모두 감소 하였으나 통계적으로 유의한 변화는 아니었으며 개별대사물의 배설 분획은 변화가 없었다. 이상의 결과로 부터 cimetidine이 theophylline의 demethylation과 8-hydroxylation대사과정 모두를 비선택적으로 억제함으로써 청소율을 감소시키고 반감기를 증가시킬 것으로 추정되었다.

• The Korean Journal of Physiology and Pharmacology
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• 제22권1호
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• pp.43-51
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• 2018

Although cisplatin is one of the most effective antitumor drugs for ovarian cancer, the emergence of chemoresistance to cisplatin in over 80% of initially responsive patients is a major barrier to successful therapy. The precise mechanisms underlying the development of cisplatin resistance are not fully understood, but alteration of DNA methylation associated with aberrant gene silencing may play a role. To identify epigenetically regulated genes directly associated with ovarian cancer cisplatin resistance, we compared the expression and methylation profiles of cisplatin-sensitive and -resistant human ovarian cancer cell lines. We identified ${\alpha}$-N-acetylgalactosaminidase (NAGA) as one of the key candidate genes for cisplatin drug response. Interestingly, in cisplatin-resistant cell lines, NAGA was significantly down-regulated and hypermethylated at a promoter CpG site at position +251 relative to the transcriptional start site. Low NAGA expression in cisplatin-resistant cell lines was restored by treatment with a DNA demethylation agent, indicating transcriptional silencing by hyper-DNA methylation. Furthermore, overexpression of NAGA in cisplatin-resistant lines induced cytotoxicity in response to cisplatin, whereas depletion of NAGA expression increased cisplatin chemoresistance, suggesting an essential role of NAGA in sensitizing ovarian cells to cisplatin. These findings indicate that NAGA acts as a cisplatin sensitizer and its gene silencing by hypermethylation confers resistance to cisplatin in ovarian cancer. Therefore, we suggest NAGA may be a promising potential therapeutic target for improvement of sensitivity to cisplatin in ovarian cancer.

• 한국발생생물학회지:발생과생식
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• 제7권2호
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• pp.61-68
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• 2003

포유동물의 초기 발생과정 중 접합체가 전능성이나 다능성을 가지기 위해서는 전반적인 DNA 메틸화를 포함하는 후성 유전학적 리프로그래밍의 복잡한 과정을 거쳐야만 한다. 본 연구팀에서는 공여핵의 후성 유전학적 리프로그래밍 과정을 조사하기 위하여 소 복제수정란에서 메틸화 양상을 분석하였다. 복제수정란의 비정상적인 메틸화 양상이 다양한 반복염기서열에서 관찰되었지만 single-copy유전자들의 염기서열은 정상적인 메틸화 양상을 보여주었다. 전반적으로 복제수정란의 전반적인 메틸화 상태는 정상수정란과 완전히 다른 양상을 보여주었다. 또한 복제 배반포의 영양외배엽세포에서 특이적으로 높은 메틸화 수준은 현 복제동물에서 빈번히 나타나는 불완전한 태반형성에 작용할 수 있을 것이다. 결론적으로 복제수정란의 비정상적 발생은 공여핵의 불완전한 후성 유전학적 리프로그래밍에 기인할 수 있다는 사실을 제시하게 되었다. 이러한 공여핵의 후성 유전학적 과정의 이해는 복제수정란의 비정상적 발생을 보다 분명히 밝힐 수 있을 것이다.

• Biomolecules & Therapeutics
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• 제21권6호
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• pp.487-492
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• 2013

Cytochrome P450 4A11 (CYP4A11) is a fatty acid hydroxylase enzyme expressed in human liver. It catalyzes not only the hydroxylation of saturated and unsaturated fatty acids, but the conversion of arachidonic acid to 20-hydroxyeicosatetraenoic acid (20-HETE), a regulator of blood pressure. In this study, we performed a directed evolution analysis of CYP4A11 using the luminogenic assay system. A random mutant library of CYP4A11, in which mutations were made throughout the entire coding region, was screened with luciferase activity to detect the demethylation of luciferin-4A (2-[6-methoxyquinolin-2-yl]-4,5-dihydrothiazole-4-carboxylic acid) of CYP4A11 mutants in Escherichia coli. Consecutive rounds of random mutagenesis and screening yielded three improved CYP4A11 mutants, CP2600 (A24T/T263A), CP2601 (T263A), and CP2616 (A24T/T263A/V430E) with ~3-fold increase in whole cells and >10-fold increase in purified proteins on the luminescence assay. However, the steady state kinetic analysis for lauric acid hydroxylation showed the significant reductions in enzymatic activities in all three mutants. A mutant, CP2600, showed a 51% decrease in catalytic efficiency ($k_{cat}/K_m$) for lauric acid hydroxylation mainly due to an increase in $K_m$. CP2601 and CP2616 showed much greater reductions (>75%) in the catalytic efficiency due to both a decrease in $k_{cat}$ and an increase in Km. These decreased catalytic activities of CP2601 and CP2616 can be partially attributed to the changes in substrate affinities. These results suggest that the enzymatic activities of CYP4A11 mutants selected from directed evolution using a luminogenic P450 substrate may not demonstrate a direct correlation with the hydroxylation activities of lauric acid.