• Molecules and Cells
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• v.39 no.3
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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.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.159-159
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• 2003

Comet assay is a potential monitoring tool because DNA strand breakage may be produced by a wide range of agents. The comet assay, also called the single-cell gell electrophoresis (SCGE) assay, is rapid and sensitive method for the detection of DNA damage in cells. This study was performed for the identification of DNA damage in the cells from flounders and clams exposed to PAHs. As a control experiments, flounder and clam cells were exposed to $H_2O$$_2$. The cells exposed to $H_2O$$_2$ were displayed a typical nuclei movement DNA damage of cells were significantly increased when the isolated cells from the blood of flounders and the tissue of clams were in vitro exposed to the different concentrations (5, 10, 50, 100 ppb) of five kinds of PAHs (benzo[a]pyrene, pyrene, fluoranthene, anthrancene, and phenanthrene). For the in vivo test, flounders and clams were exposed to the different concentrations of BaP for 4 days. The results showed that DNA strand breakage was effected by the concentration of BaP and the duration of exposure. In high concentration of BaP, the mean tail lengths of nuclei was longer than it In low concentration, while the mean size of head DNA decreased. In this research, both in vitro and in vivo genotoxicity of PAHs could be biomonitored by the comet assay. Especially, clams and flounders seem to be useful as materials for monitoring genotoxic damage by comet assay.

• Journal of the Korean Society of Food Culture
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• v.19 no.2
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• pp.129-138
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• 2004

The changes in DNA damage were investigated during storage after irradiation. Beef, pork and chicken were irradiated at 1.0, 3.0 and 5.0 kGy and stored for 6 months at $-20^{\circ}C$. The comet assay was applied to the sample muscles at the beginning of irradiation and at the end of storage. Muscles were isolated, sliced, and the suspended cells were embedded in an agarose layer. After lysis of the cells, they were electrophoresed for 2 min. and then stained. DNA fragmentation in tissues caused by irradiation was quantified as tail length and tail moment (tail length ${\times}$ % DNA in tail) by comet image analyzing system. Right after irradiation, the differences in tail length between unirradiated and irradiated muscles were significant(p<0.05) in beef, pork and chicken. With increasing the increasing doses, statistically significant longer extension of the DNA from the nucleus toward anode was observed. Similarly even 6 months after irradiation, all the irradiated muscles significantly showed longer tail length than the unirradiated controls. The results represented as tail moment showed similar tendency to those of tail length, but the latter parameter was more sensitive than the former. These results indicate that the comet assay could be one of the simple methods of detecting irradiated muscles. Moreover, this method suggest that using comet assay, we were able to detect DNA damage differences even after 6 months after irradiation.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2002.11a
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• pp.145-153
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• 2002

유해 화학 물질류에 의해 오염된 해양 환경 시료의 환경독성 수준을 평가하기 위하여 다양한 화학물질에 대해 민감성이 우수한 생물학적 독성평가기법을 개발 하고자하였다. 지속성 유기오염 물질 중 다환 방향 족 탄화수소(PAHs)를 처리한 광어(Conger myriaster)와 개조개(Saxidomus pupurata)의 DNA 손상정도를 single cell gel electrophoresis assay(comet assay)를 통해 분석하였다. PAHs 중 광양만에서 높은 농도로 검출되는 benzo(a)pyrene을 농도별(0, 10, 50, 100 ppb)로 처리한 후 2일과 4일에 광어의 혈액세포와 개조개의 근육세포를 채취해 comet assay를 실시하였다. benso(a)pyrene에 대한 DNA 손상정도를 처리된 농도와 생물종에 따라 다르게 나타났는데 광어의 혈액세포는 2일에 가장 DNA 손상정도가 높았고, 4일에는 회복되는 경향을 나타냈다. 개조개의 근육세포는 시간이 지나면서 DNA 손상정도가 증가하는 경향을 보였다. 이와 같은 결과는 comet assay 기법이 유해 화학물질로 오염된 해양생물 종의 환경독성을 검색하는 유용한 수단이 될 수 있음을 보여준다.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.3
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• pp.245-251
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• 2010

Objective: Human sperm nucleus DNA damage may negatively affect pregnancy outcome, and the spermatozoa of infertile men have more DNA damage than that of fertile men. The aim of this study was to evaluate the effect of microsurgical varicocelectomy on human sperm nucleus DNA integrity. Methods: We reviewed the medical records of 18 subfertile male patients who underwent microsurgical varicocelectomy at our hospital from April 2006 to April 2007. Varicocele was diagnosed by physical examination and Doppler ultrasound. Standard semen analysis was performed in 18 patients before and 4 months after microsurgical varicoceletcomy using a computer assisted semen analyzer. Sperm nucleus DNA integrity was assessed by a single-cell gel electrophoresis (comet assay). Results: No recurrence of varicocele was observed after 4 months later. The DNA fragmentation index improved after varicocelectomy compared with pre-operatively (19.3 versus 13.7%, respectively, p<0.05). Semen analysis parameters (total count, concentration, motile sperm, viability, strict morphology) increased after varicocelectomy, but the difference did not reach statistical significance. Conclusion: Our data suggest that microsurgical varicocelectomy can improve semen analysis parameters and human sperm nucleus DNA integrity in infertile men with varicocele.

• YAKHAK HOEJI
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• v.55 no.3
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• pp.251-259
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• 2011

Cigarette smoke condensate (CSC) is known to be carcinogenic compound. CSC contains many organic compounds such as polycyclic aromatic hydrocarbons (PAHs), and heterocyclic amine compounds (HCAs). Reactive oxygen species (ROS) are also generated and induce oxidative DNA damage during the metabolism of CSC. The rat microsome mediated and DNA repair enzyme treated comet assays together with conventional comet assay were performed to evaluate the mechanisms of CSC genotoxicity. The organic extract of CSC induced oxidative and microsome mediated DNA damage. Vitamin C as a model antioxidant reduced DNA damage in endonuclease III treated comet assay. One of flavonoid, galangin as a CYP1A1 inhibitor, reduced DNA damage in the presence of S-9 mixture. The ethanol extracts of the mixed vegetables (BV) or the mixed fruits (BF) showed potent inhibitory effects against CSC induced DNA damage with oxidative DNA lesions and in the prescence of S-9 mixture. These results indicate that BV and BF could prevent CSC-induced cellular DNA damage by inhibiting oxidative stress and suppressing cytochrome P450 in mammalian cells.

• Journal of Nutrition and Health
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• v.36 no.1
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• pp.24-31
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• 2003

The present study was attempted to investigate the antioxidant capacity of popular yellow-green vegetable juices (kale, Angelica keishei, carrot, small water dropwort) and to investigate the effect of vegetable juices on protecting oxidative damage to DNA in cultured Chinese hamster lung (CHL) cells. Antioxidant capacity was analyzed by TRAP assay (Total radical-trapping antioxidant potential). Cellular DNA dmamage was measured by SCGE (single-cell gel electrophoresis, also known as comet assay. Cells incubated in medium with PBS (negative control) or with various concentration of the freeze dried green juices (25, 50, 100, 250 $\mu\textrm{g}$/$m\ell$) resuspended in PBS were treated with $H_2O_2$ (200 ${\mu}{\textrm}{m}$) as an oxidative stimulus for 5 min at 4$^{\circ}C$. The physiological function of each vegetable juice on oxidative DNA damage was analyzed and expressed as tail moment (tail length X percentage migrated DNA in tail) . Kale juice had the highest TRAP value suggesting that kale has the highest antioxidant capacity followed by Angelica keishei, small water dropwort and carrot. Cells treated with $H_2O_2$ had extensive DNA damage compared with cells treated with PBS or pre-treated with vegetable juice extracts. All green juices inhibited $H_2O_2$-induced DNA damage with kale being the most effective juice among the tested juices. These results indicate that green juice supplementation to CHL cells followed by oxidative stimulus inhibited damage to cellular DNA, supporting a protective effect against oxidative damage induced by reactive oxygen species. (Korean J Nutrition 36(1) : 24-31, 2003)

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.05a
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• pp.116-116
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• 2001

The alkaline Comet assay has been used with increasing popularity to investigate the level of DNA damage in terms of strand breaks and alkaline labile sites in biomonitoring studies within the last decade in western countries.(omitted)

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.350-354
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• 2015

BACKGROUND: Botanical insecticides, especially Azadirachta Indica extract (AIE) and Sophorae radix extract (SRE) are widely used in Agriculture field. In our previous studies on genotoxicity test of AIE and SRE samples, a suspicious clastogenic properties was shown. Herein, we investigated the DNA damage effect of these botanical insecticide samples through the in vitro comet assay. METHODS AND RESULTS: Chinese hamster lung (CHL) fibroblast cell line was used, and methyl methanesulphonate was as positive control. Respective two samples of AIE and SRE were evaluated using Single Cell Gel Electrophoresis (Comet) assay and measured as the Olive tail moment (OTM). Results from this study indicated that all tested AIE and SRE samples did not show DNA damage in comet assay using CHL cells, compared with control. CONCLUSION: AIE and SRE samples used in this study were not cause genetic toxicity and are suitable for use as organic materials.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.77-84
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• 2000

Although ferric sulfate has been proposed as an alternative to formocresol in pulpotomy treatment in primary teeth, it has been given little concern regarding its cytotoxicity and mutagenicity. In the present study, we assessed the in vitro genotoxic effect of a ferric sulfate on human gingival fibroblast cell line (HGF-1). DNA damage was evaluated using comet assay (single cell alkaline gel electrophoresis) and obtained the results as follows: 1. A dose-response relationship was found between ferric sulfate concentrations (0 to 5mM) and DNA damages. 2. Above the concentration of 0.1mM, DNA damage was significantly increased than those of the control (p<0.05). 2. At the fixed concentration of 0.05mM, no significant difference was found between exposure time and DNA damage. These findings suggest that ferric sulfate as a pulpotomy agent can induce DNA damage in human gingival fibroblasts.