• BMB Reports
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• 제36권3호
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• pp.305-311
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• 2003

A modified actinomycin D was prepared with a hydroxyl group that replaced the amino group at the chromophore 2-position, a substitution known to strongly reduce affinity for double-stranded DNA. Interactions of the modified drug on single-stranded DNAs of the defined sequence were investigated. Competition assays showed that 2-hydroxyactinomycin D has low affinity for two oligonucleotides that have high affinities ($K_a\;=\;5-10{\times}10^6\;M^{-1}$ oligomer) for 7-aminoactinomycin D and actinomycin D. Primer extension inhibition assays performed on several single-stranded DNA templates totaling around 1000 nt in length detected a single high affinity site for 2-hydroxyactinomycin D, while many high affinity binding sites of unmodified actinomycin D were found on the same templates. The sequence selectivity of 2-hydroxyactinomycin D binding is unusually high and approximates the selectivity of restriction endonucleases. Binding appears to require a complex structure, including residues well removed from the polymerase pause site.

• 한국식품위생안전성학회지
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• 제31권1호
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• pp.1-7
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• 2016

본 연구의 목적은 NIH3T3와 HepG2 세포에서 에탄올 유도 세포독성 및 유전독성에 대하여 녹차엑기스(GTE)와 epigallocatechin-3-gallate (EGCG)의 보호작용을 평가하는데 있다. 세포생존율은 MTT assay를 실시하였으며 DNA 손상도는 Comet assay로 실시한 결과 에탄올은 농도의존적인 세포독성과 유전독성을 나타내었다. 한편 GTE와 EGCG는 에탄올 유도 세포독성 및 DNA 손상에 대하여 유의성 있는 억제효과를 나타내었으며 DPPH시험과 LDL oxidation 및 8OH-2'dG 생성시험에서 항산화효과를 나타내었다. 한편 녹차성분 함유 시판 리큐르주도 순수 에탄올에 비하여 세포독성억제 및 DNA 손상억제효과를 나타내었다. 이상의 시험결과 GTE와 함유 EGCG는 항산화성 유전독성억제기전을 통한 에탄올독성저감 물질로 판단된다.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.342-342
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• 2006

Atomic force microscope (AFM) enables us to stretch a single polymer chain by picking it at its two modified termini. Using this method called "nanofishing," we have studied statistical properties of single polymer chains. A force-extention curve obtained for a polystyrene with thiol termini in a cyclohexane showed a good agreement with a worm-like chain (WLC) model, and thus gave microscopic information about entropic elasticity. In this report, the experiments were performed at wide-range temperatures, resulting in wide-range solvent qualities from poor to good solvent condition. The temperature dependence of statistical properties of polystyrene was examined. The coil-strand transformation realized in a poor solvent was also discussed.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2003년도 봄 학술발표논문집 Vol.30 No.1 (B)
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• pp.476-478
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• 2003

1-Base의 non Watson-Crick 결합과, Dangling end(결합이 이루어진 두 개의 DNA strand 중 한쪽 끝이 다른 쪽 끝보다 짧은 경우)를 허용하는 nearest-neighbor model을 사용하여 DNA/DNA Hybridization 예측 시스템을 구현하였다. DNA 컴퓨팅을 기존의 실리콘 컴퓨터를 이용하여 접근하는 이러한 방법은 좀 더 효율적인 분자 알고리즘의 개발과 DNA 컴퓨팅에 사용될 수 있는 더욱 신뢰성 있는 DNA 시퀀스의 설계에 도움을 줄 수 있을 것이다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2005년도 한국식물병리학회 임시총회 및 춘계학술발표회
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• pp.53.2-54
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• 2005

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2005년도 2005 Annual Meeting & International Symposium
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• pp.342-342
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• 2005

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.314.2-314.2
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• 2002

DNA topoisomerases catalyze changes in DNA topology through cycles of transient DNA strand breakage and religation. During this process. the active site tyrosine in human DNA topoisomerase Ⅰ(Top Ⅰ) becomes covalently linked to the 3'-ends of a single-stranded nick in the DNA duplex, Stabilization of the Top Ⅰ-DNA cleavable complex is the common initial event leading to the cytotoxicity of top 1 inhibitors. (omitted)

• 환경생물
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• 제22권4호
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• pp.507-512
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• 2004

This study was focused on the risk assessment of whether radiofrequency electromagnetic fields generated by mobile phone is cytogenetically toxic or not. We conducted the effects of 835-MHz electromagnetic field (EMF) on DNA strand breaks in mouse thymic lymphoma L5178Y $Tk^{+/1-}$ cells using alkaline comet assay. EMF frequency 835-MHz we chosen is one of the most popular communication frequency bands in Korean code-division multiple-access (CDMA) mobile phone system. The cells were exposed to 835-MHz EMF alone or 835-MHz EMF combined with cyclophosamide(CPA) or 4-nitroquinoline-1-oxide (4NQO) at specific absorption rate (SAR) of 4.0 W $kg^{-l}$ for 24 and 48hrs. DNA damage expressed as tail moment was increased more than two-fold after exposure to 835-MHz EMF for 24 and 48hr. In particular, CPA for 48hr and 4NQO for 24 hr enhanced notably the tail moment to 9-fold and 16-fold in the presence of 835-MHz EMF, respectively, compared to each single treatment. From these results, it appears that exposure to CDMA-mobile phone radiation at 835-MHz frequency may potentiate DNA strand breaks of mouse thymic lymphoma L5178Y $Tk^{+/1-}$;cells under the defined conditions of this study.

• Animal cells and systems
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• 제9권2호
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• pp.79-85
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• 2005

Oxidized abasic residues arise as a major class of DNA damage by a variety of agents involving free radical attack and oxidation of deoxyribose sugar components. 2-deoxyribonolactone (dL) is a C1'-oxidized abasic lesion implicated in DNA strand scission, mutagenesis, and covalent DNA-protein cross-link (DPC). We show here that mammalian cell-free extract give rise to stable DPC formation that is specifically mediated by dL residue. When a duplex DNA containing dL at the site-specific position was incubated with cell-free extracts of Po ${\beta}-proficient$ and -deficient mouse embryonic fibroblast cells, the formation of major dL-mediated DPC was dependent on the presence of DNA polymerase (Pol) ${\beta}$. Formation of dL-specific DPC was also observed with histones and FEN1 nuclease, although the reactivity in forming dL-mediated DPC was significantly higher with Pol ${\beta}$ than with histones or FEN1. DNA repair assay with a defined DPC revealed that the dL lesion once cross-linked with Pol ${\beta}$ was resistant to nucleotide excision repair activity of cell-free extract. Analysis of nucleotide excision repair utilizing a model DNA substrate containing a (6-4) photoproduct suggested that excision process for DPC was inhibited because of DNA single-strand incision at 5' of the lesion. Consequently DPC mediated by dL lesion may not be readily repaired by DNA excision repair pathway but instead function as unusual DNA damage causing a prolonged DNA strand break and trapping of the major base excision repair enzyme.

• 한국동물학회지
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• 제26권3호
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• pp.171-179
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• 1983

MMS와 자외선에 의한 DNA의 절제회복과 단사절단에 미치는 poly(ADP-ribose) polymerase의 저해제인 3-aminobenzamide의 영향을 CHO 세포를 재로로 조사하여 다음과 같은 결과를 얻었다. 1. MMS에 의한 비주기성 DNA 합성률과 DNA 단사 절단률은 이 저해제에 의해 모두 증가하였다. 이는 poly (ADP-ribose) polymeraserk MMS에 의해 유발된 염기 절제회복의 incision step를 억제하는 결과라 생각된다. 2. 자외선에 의한 비주기성 DNA 합성률과 DNA단사 절단률은 이 저해제에 의해 모두 감소하였다. 이는 poly(ADP-ribose) polymerase가 자외선에 의해 유발된 nucleotide 절제회복의 incision step을 돕는 작용을 하는 결과로 생각된다. 3. MMS와 자외선을 복합처리한 실험군에서는, DNA 단사 절단률은 이 저해제에 의해 영향을 받지 않았으며, 비주기성 DNA 합성률은 자외선 단독 처리군의 수준으로 증가되었다. 이는, 이 저해제가 MMS와 자외선으로 유발된 절제회복의 incision step에는 독립적으로 작용하며, 그 이후의 단계에서, MMS에 의해 부분적으로 불활성화 되었던 pyrimidine dimers의 절제를 완전하게 해주는 것으로 해석된다.