• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2023년도 임시총회 및 춘계학술대회
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• pp.54-54
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• 2023

Nypa fruticans Wurmb (N. fruticans) is a plant that belongs to Araceae and N. fruticans is mainly found in tropical mangrove systems. The parts (leaves, stems, and roots) of N. fruticans are traditionally used for asthma, sore throat, and liver disease. N. fruticans contains flavonoids and polyphenols, which are substances that have inhibitory effects on cancer and oxidant. In previous studies, some pharmaceutical effects of N. fruticans on melanogenesis and inflammation have been reported. The present study is conducted to investigate the effect of the ethyl acetate fraction of N. fruticans (ENF) on oxidative DNA damage and UVB-induced DNA damage. DNA damage response (DDR) pathway is important in research on cancer, apoptosis, and so on. DDR pathways are considered a crucial factor affecting the alleviation of cellular damage. ENF could reduce oxidative DNA damage derived from reactive oxygen species by the Fenton reaction. Also, ENF reduced the intensity of intracellular ROS in the live cell image by DCFDA assay. UVB is known to cause skin and cellular damage, then finally contribute to causing the formation of tumors. As for the strategies of reducing DNA damage by UVB, inhibition of p53, H2AX, and Chk2 can be important indexes to protect the human body from DNA damage. As a result of confirming the protective effect of ENF for UVB damage, MMPs significantly decreased, and the expression of apoptosis-related factors tended to decrease. In conclusion, ENF can provide protective effects against double-stranded DNA break (DSB) caused by oxidative DNA damage and UVB-induced DNA damage. These results are considered to be closely related to the protective effect against radicals based on catechin, epicatechin, and isoquercitrin contained in ENF. Based on these results, it is thought that additional mechanism studies for inhibiting cell damage are needed.

• 한국환경성돌연변이발암원학회지
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• 제22권3호
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• pp.164-168
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• 2002

Phthalate analogues are a plasticizer and solvent used in industry and were reported to be a potential carcinogen classified in the category of suspected endocrine disruptors. Most common human exposure to these compounds may occur with contaminated food. They may migrate into food from plastic wrap or may enter food from general environmental contamination. Since these substances are not limited to the original products, and enter the environment, they have become widespread environmental pollutants, thus leading to a variety of phthalates that possibly threaten the public health. To determine whether seven phthalate analogues i.e. diallyl phthalate, diisodecyl phthalate, di-n-nonyl phthalate, butyl benzyl phthalate, di-n-octyl phthalate, di-tridecyl phthalate, and dibutyl phthalate, can induce DNA strand breakage that is one of the various factors related to the mechanism of carcinogenicity, the comet assay which has been widely used for the detection and measurement of DNA strand breaks, was conducted in L5178Y mouse lymphoma cells. From these results, seven phthalates revealed dose-dependent decrease of cell viability, however, no remarkable cytotoxicity was observed even at high concentration of 100 $\mu\textrm{g}$/$m\ell$ phthalates. And also, the results showed that the induction of DNA strand breaks by seven phthalates was not significantly different from the control in this study.

• Journal of electromagnetic engineering and science
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• 제15권3호
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• pp.134-141
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• 2015

The effect of a 60 Hz time-varying electric field was studied using a facing-electrode device (FED) and a coplanar-electrode device (CED) for further investigation of the genotoxicity of 60 Hz time-varying magnetic field (MF) from preceding research. Neither a single 30-minute exposure to the CED or to the FED had any obvious biological effects such as DNA double strand break (DSB) and apoptosis in cancerous SCC25, and HeLa cells, normal primary fibroblast IMR90 cells, while exposures of 60 Hz time-varying MF led to DNA damage with induced electric fields much smaller than those used in this experiment. Nor did repetitive exposures of three days or a continuous exposure of up to 144 hours with the CED induce any DNA damage or apoptosis in either HeLa or IMR90 cells. These results imply that the solitary electric field produced by time-varying MF is not a major cause of DSBs or apoptosis in cancer or normal cells.

• 한국영양학회:학술대회논문집
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• 한국영양학회 1998년도 추계학술대회 초록
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• pp.74-74
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• 1998

• Radiation Oncology Journal
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• 제8권2호
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• pp.137-144
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• 1990

Filter elution 방법으로 EL 4백서 백혈병 세포 및 C57BL/6백서 유래의 비장 임파구에 대한 Co-60 $\gamma$ 선의 DNA single-strand breaks (SSB) 효과를 정량적으로 측정하였다. 임파구는 [${^3}H$]thymidine을 표지하기 위하여lipopolysaccharide (LPS, 20 $\mug/ml$)를 첨가하여 자극하고 부유 상태의 EL 4 세포 및 임파구를 $0^{\circ}C$에서 0 Gy, 1 Gy, 5 Gy, 10 Gy 또는 15 Gy조사하였으며, elution용액의 pH는 12.1로 하였다. $\gamma$ 선 조사에 따른 single-strand breaks의 수는 방사선 조사량에 따라 증가 하였으며 21 ml elution 양을 기준으로 한 strand scission factor (SSF)는 EL 4 세포에서 $0.01301\pm0.00096\;Gy^{-1}(n=5)$이었고, 임파구는 $0.01097\pm0.00091\;Gy^{-1}(n=5)$를 나타내므로 본 실험에서는 EL 4 세포가 정상 임파구에 비하여 방사선에 의한 DNA SSB가 민감함을 알 수 있었다(p<0.005). 본 연구 결과 DNA strand breaks의 측정법을 이용하여 방사선의 특성 및 생물학적 효과의 파악은 물론 나아가 기존의 방호제 및 새로운 약제의 DNA에 대한 효과를 판별할 수 있을 것이다.

• Journal of Radiation Protection and Research
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• 제33권2호
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• pp.53-59
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• 2008

X선과 같은 고에너지 방사선에 의한 DNA 손상 중 간접적인 손상을 확인하기 위하여 탄탈륨(Ta) 박막위에 동결건조 과정으로 만들어진 pGEM-3Zf(-) plasmid DNA 단일층(monolayer)의 박막을 만든 다음, 에너지가 1.5 keV인 Al $K{\alpha}$ X선을 0분, 3분, 7분, 10분 동안 초고진공 상태에서 이 DNA 단일층에 조사하여 평균 흡수선량(mean absorbed dose)의 변화에 따른 DNA 손상을 관찰하였다. 또한 3 eV의 낮은 에너지 전자선을 조사하여 그 결과를 X선을 조사한 경우와 비교하였다. X선과 낮은 에너지 전자선으로 조사된 plasmid DNA를 전기영동(electrophoresis) 방법을 이용해 supercoiled DNA와 unsupercoiled DNA로 분리한 후 각각을 정량적으로 분석하였다. Supercoiled DNA는 X선과 3 eV 전자선의 조사에 따른 평균흡수선량이 증가함에 따라 선형적으로 감소했다. 그와 반대로 circular DNA와 crosslinked form 1 DNA는 평균흡수선량이 증가함에 따라 선형적으로 증가했다. 이것은 supercoiled DNA가 낮은 에너지 전자와 상호작용하여 외가닥 절단(single strand break)을 일으켰고 그 결과 unsupercoiled DNA로 변화되었음을 보여준다. 본 실험을 통해 X선과 같은 고에너지 방사선에 의한 DNA의 간접적 손상이 일어남을 관찰할 수 있었고, DNA의 이온화 에너지보다 작은 에너지($0{\sim}10\;eV$)를 갖는 전자에 의해서도 DNA 손상이 일어날 수 있음을 확인할 수 있었다.

• Molecules and Cells
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• 제39권3호
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• pp.204-210
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• 2016

DNA damage responses are important for the maintenance of genome stability and the survival of organisms. Such responses are activated in the presence of DNA damage and lead to cell cycle arrest, apoptosis, and DNA repair. In Caenorhabditis elegans, double-strand breaks induced by DNA damaging agents have been detected indirectly by antibodies against DSB recognizing proteins. In this study we used a comet assay to detect DNA strand breaks and to measure the elimination of DNA strand breaks in mitotic germline nuclei of C. elegans. We found that C. elegans brc-1 mutants were more sensitive to ionizing radiation and camptothecin than the N2 wild-type strain and repaired DNA strand breaks less efficiently than N2. This study is the first demonstration of direct measurement of DNA strand breaks in mitotic germline nuclei of C. elegans. This newly developed assay can be applied to detect DNA strand breaks in different C. elegans mutants that are sensitive to DNA damaging agents.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.92.1-92.1
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• 2013

Molecular electronics has been the subject of intese research for many years because of the fundamental interest in molecular charge transport and potential applications, such as (bio)nanosensors and molecular memory devices. Molecular electronics requires a method for making reliable eletrical contacts to singlemolecules. To date, several approaches have been reported: scanning-probe microscopy, mechanical break junctions, nano patterning, and direct deposition of electrode on a self-assembled monolayers. However, most methods are laborious and difficult for large-scale application and more importantly, cannot control the number of moleucles in the junction. Recently, DNA has been used as a template for metallic nanostructures (e.g., Ag, Pd, and Au nanowires) through DNA metallization process. Furthermore, oligodeoxynucleotides have been tethered to organic molecules by using conventional organic reactions. Collectively, these techniques should provide an efficient route toward reliable and reproducible molecular electronic devices with large-scale fabrication. Therefore, I will present a paradigm for the fabrication of moleuclar electronic devices by using micrometer-sized DNA-singe organic molecule and DNA triblock structures.

• Radiation Oncology Journal
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• 제11권2호
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• pp.219-225
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• 1993

각 방사선량의 조사에 따른 사람 정상임파구, 마우스 정상임파구, 그리고 EL-4마우스 백혈병 세포의 DNA double strand breaks 발생율에 대하여 비교분석 하였던 바 다음과 같은 결과를 얻었다. LPS와 PHA를 첨가하여 각각 배양한 마우스 정상임파구의 DNA double strand breaks의발생율을 strand scission factor의 기울기로 비교평가해 본 바 LPS를 첨가배양한 군이 DNA DSB가 더 많이 형성되었다(P<0.005). 이것으로 볼 때 DNA double strand breaks발생에 있어서는 B cells이 T cells보다 더 민감하였다. 또한 EL-4 백혈병 세포는 정상 임파구보다 유의하게 DNA DSB가 더 많이 형성된 것이 관찰되었다(p<0.005). 한편 사람 정상임파구와 마우스 정상임파구 사이의 intrinsic radiosensitivity는 시험관내 실험에서 비교적 유사한 kinetics를 나타냈으나, 마우스 정상임파구가 사람 정상임파구보다 DNA DSB수율이 더 낮았다. 그래서 방사선을 조사하고 3.5시간이 지난후에 $10\%$ DNA DSB발생에 필요한 선량을 두 군간에 비교평가해 본 바 마우스 정상임파구의 선량이 더 높게 나타났다. 이상의 실험결과를 정확하게 설명하기는 어 렵지만 아마도 환경적인 요인과 유전적인 요인 때문인 것으로 사료되었다. 그리고 본 연구결과는 방사선조사에 따른 임상반응의 이해와 cytometric assessment의 방사선 생물학적 parameter로 이용될 수 있을 것으로 판단되었다.

• 약학회지
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• 제54권1호
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• pp.32-38
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• 2010

The aim of this study was to evaluate the effect of galangin towards hydrogen peroxide-induced DNA damage. The calf thymus DNA and Chinese Hamster Lung (CHL) cells were used to measure 8-hydroxy-2'-deoxyguanosine(8-OH2'dG) as an indicator of DNA oxidative damage using high performance liquid chromatography with electrochemical detection. Hydrogen peroxide in the presence of Fe(II) ion induced the formation of 8-OH2'dG in both calf thymus DNA and CHL cells. The DNA damage effects were enhanced by increasing the concentration of Fe(II) ion and inhibited by galangin. In the single cell gel electrophoresis (Comet assay), galangin and dl-a-tocopherol showed an inhibitory effect in CHL on hydrogen peroxide induced DNA single strand breaks. Galangin showed more potent activity than dl-$\alpha$-tocopherol under our experimental conditions. These results indicate that galangin can modify the action mechanisms of the oxidative DNA damage and may act as chemopreventive agents against oxidative stress.