• Title, Summary, Keyword: DNA Damage

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Effect of Low-Energy Electron Irradiation on DNA Damage by Cu2+ Ion

  • Noh, Hyung-Ah;Park, Yeunsoo;Cho, Hyuck
    • Journal of Radiation Protection and Research
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    • v.42 no.1
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    • pp.63-68
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    • 2017
  • Background: The combined effect of the low energy electron (LEE) irradiation and $Cu^{2+}$ ion on DNA damage was investigated. Materials and Methods: Lyophilized pBR322 plasmid DNA films with various concentrations (1-15 mM) of $Cu^{2+}$ ion were independently irradiated by monochromatic LEEs with 5 eV. The types of DNA damage, single strand break (SSB) and double strand break (DSB), were separated and quantified by gel electrophoresis. Results and Discussion: Without electron irradiation, DNA damage was slightly increased with increasing Cu ion concentration via Fenton reaction. LEE-induced DNA damage, with no Cu ion, was only 6.6% via dissociative electron attachment (DEA) process. However, DNA damage was significantly increased through the combined effect of LEE-irradiation and Cu ion, except around 9 mM Cu ion. The possible pathways of DNA damage for each of these different cases were suggested. Conclusion: The combined effect of LEE-irradiation and Cu ion is likely to cause increasing dissociation after elevated transient negative ion state, resulting in the enhanced DNA damage. For the decrease of DNA damage at around 9-mM Cu ion, it is assumed to be related to the structural stabilization due to DNA inter- and intra-crosslinks via Cu ion.

Recognition of DNA Damage in Mammals

  • Lee, Suk-Hee
    • BMB Reports
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    • v.34 no.6
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    • pp.489-495
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    • 2001
  • DNA damage by UV and environmental agents are the major cause of genomic instability that needs to be repaired, otherwise it give rise to cancer. Accordingly, mammalian cells operate several DNA repair pathways that are not only responsible for identifying various types of DNA damage but also involved in removing DNA damage. In mammals, nucleotide excision repair (NER) machinery is responsible for most, if not all, of the bulky adducts caused by UV and chemical agents. Although most of the proteins involved in NER pathway have been identified, only recently have we begun to gain some insight into the mechanism by which proteins recognize damaged DNA. Binding of Xeroderma pigmentosum group C protein (XPC)-hHR23B complex to damaged DNA is the initial damage recognition step in NER, which leads to the recruitment of XPA and RPA to form a damage recognition complex. Formation of damage recognition complex not only stabilizes low affinity binding of XPA to the damaged DNA, but also induces structural distortion, both of which are likely necessary for the recruitment of TFIIH and two structure-specific endonucleases for dual incision.

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Buddleja officinalis prevents the normal cells from oxidative damage via antioxidant activity

  • Hong, Se-Chul;Jeong, Jin-Boo;Jeong, Hyung-Jin
    • Korean Journal of Plant Resources
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    • v.21 no.6
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    • pp.449-456
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    • 2008
  • The flowers of Buddleja officinalis are used to treat sore and damaged eyes, a condition which is similar to skin wounds. However, whether it has any protective effect on oxidative DNA damage and cell death induced by hydroxyl radical remains unclear. In this study, we evaluated the protective effects of the extracts against oxidative DNA and cell damage caused by hydroxyl radical. DPPH radical, hydroxyl radical, hydrogen peroxide and intracellular ROS scavenging assay, and $Fe^{2+}$ chelating assay were used to evaluate the antioxidant properties. phi X 174 RF I plasmid DNA and intracellular DNA migration assay were used to evaluate the protective effect against oxidative DNA damage. Lastly, MTT assay and lipid peroxidation assay were used to evaluate the protective effect against oxidative cell damage. It was found to prevent intracellular DNA and the normal cells from oxidative damage caused by hydroxyl radical via antioxidant activities. These results suggest that Buddleja officinalis may exert the inhibitory effect on ROS-induced carcinogenesis by blocking oxidative DNA damage and cell death.

Free Radical Involvement in the DNA Damaging Activity of Fumonisin Bl

  • Lee, Wan-Hee;Lee, Kil-Soo
    • Toxicological Research
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    • v.17 no.4
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    • pp.249-253
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    • 2001
  • Fumonisin B1, a mycotoxin, is thought to induce esophageal cancer in humans and apoptosis in animal cells by inhibiting ceramide synthase. Dumonisin Bl may also generate reactive oxygen species directly or indirectly, leading to DNA damage and lipid peroxidation. In this study, a DNA fragmentation assay, dichlorofluorescein (DCF) analysis, and single cell gel electrophoresis (SCGE) were used to investigate the involvement of cellular free radicals, specifically hydrogen peroxide, in the DNA damaging activity of fumonisin B1. From an in vitro DNA fragmentation assay, E. coli DNA, damage by fumonisin Bl was increased by the addition of superxide dismutase (SOD) and decreased by catalase. SCGE and DCF analysis in vivo showed that the nuclear DNA damage and intracellular free radicals in cultured rat hepatocytes treated with fumonisin B1 were increased with the concentration of fumonisin Bl . DNA damage and free radical generation were inhibited by the addition of catalase. Fumonisin Bl , in the presence of SOD, produces hydrogen peroxide causing oxidative DNA damage and protein malfunction, leading to genotoxicity and cytotoxicity of the toxin.

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Lycopene-Induced Hydroxyl Radical Causes Oxidative DNA Damage in Escherichia coli

  • Lee, Wonyoung;Lee, Dong Gun
    • Journal of Microbiology and Biotechnology
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    • v.24 no.9
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    • pp.1232-1237
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    • 2014
  • Lycopene, which is a well-known red carotenoid pigment, has been drawing scientific interest because of its potential biological functions. The current study reports that lycopene acts as a bactericidal agent by inducing reactive oxygen species (ROS)-mediated DNA damage in Escherichia coli. Lycopene treatment elevated the level of ROS-in particular, hydroxyl radicals ($^*OH$)-which can damage DNA in E. coli. Lycopene-induced DNA damage in bacteria was confirmed and we also observed cell filamentation caused by cell division arrest, an indirect marker of the DNA damage repair system, in lycopene-treated E. coli. Increased RecA expression was observed, indicating activation of the DNA repair system (SOS response). To summarize, lycopene exerts its antibacterial effects by inducing $^*OH$-mediated DNA damage that cannot be ameliorated by the SOS response. Lycopene may be a clinically useful adjuvant for current antimicrobial therapies.

Nuclear DNA Damage and Repair in Normal Ovarian Cells Caused by Epothilone B

  • Rogalska, Aneta;Marczak, Agnieszka
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.15
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    • pp.6535-6539
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    • 2015
  • This study was designed to assess, whether a new chemotherapeutic microtubule inhibitor, Epothilone B (EpoB, Patupilone), can induce DNA damage in normal ovarian cells (MM14.Ov), and to evaluate if such damage could be repaired. The changes were compared with the effect of paclitaxel (PTX) commonly employed in the clinic. The alkaline comet assay technique and TUNEL assay were used. The kinetics of DNA damage formation and the level of apoptotic cells were determined after treatment with IC50 concentrations of EpoB and PTX. It was observed that PTX generated significantly higher apoptotic and genotoxic changes than EpoB. The peak was observed after 48 h of treatment when the DNA damage had a maximal level. The DNA damage induced by both tested drugs was almost completely repaired. As EpoB in normal cells causes less damage to DNA it might be a promising anticancer drug with potential for the treatment of ovarian tumors.

Application of the Alkaline Comet Assay for Detecting Oxidative DNA Damage in Human Biomonitoring (인체 산화적 DNA손상에 대한 Human Biomonitoring도구로서 Alkaline Comet Assay의 활용 가능성 연구)

  • 박은주;강명희
    • Journal of Nutrition and Health
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    • v.35 no.2
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    • pp.213-222
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    • 2002
  • The alkaline comet assay has been used with increasing popularity to investigate the level of DNA damage in biomonitoring studies within the last decade in Western countries. The purpose of this study was to evaluate the usefulness of the alkaline comet assay as a biomarker of oxidative DNA damage for monitoring in the Korean population, and also to evaluate the effect of nutritional status and lifestyle factors on H2O2 induced oxidative DNA damage measured by the alkaline comet assay in human lymphocytes. The study population consisted of 61 healthy Korean male volunteers, aged 20-28. Epidemiological background data including dietary habits, smoking habits and anthropometrical measurements were collected through personal interviews. After blood collection, the comet assay in peripheral lymphocytes and plasma lipids analysis was carried out and the results analyzed. Tail moment (TM) and tail length (TL) of the comet assay were use\ulcorner to measure DNA damage in the lymphocytes of the subjects. Statistically significant (p < 0.05) positive correlations were observed between DNA damage (TM or TL) and smoking habits expressed as cigarettes smoked per day and pack years (r = 0.311 and 0.382 for TM, r = 0.294 and 0.350 for TL, respectively). There were also significant positive correlations between DNA damage parameter and waist-hip ratio. Higher plasma triglyceride levels were associated with increased damage to DNA. There were no correlations between the consumption frequencies of vegetables and DNA damage to the subjects. However, consumption frequencies of fruit and fruit juice intake were inversely associated with the TM and TL. The results indicate that die comet assay is a simple, rapid and sensitive method for detecting lymphocyte DNA damage induced by cigarette smoking. Consumption of fruit or fruit juices could potentiall modify the damaged DNA in the human peripheral lymphocytes of young Korean men.

Protection of Radiation-Induced DNA Damage by Functional Cosmeceutical Poly-Gamma-Glutamate

  • Oh, Yu-Jin;Kwak, Mi-Sun;Sung, Moon-Hee
    • Journal of Microbiology and Biotechnology
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    • v.28 no.4
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    • pp.527-533
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    • 2018
  • This study compared the radioprotective effects of high-molecular-weight poly-gamma-glutamate (${\gamma}-PGA$, average molecular mass 3,000 kDa) and a reduced form of glutathione (GSH, a known radioprotector) on calf thymus DNA damage. The radiation-induced DNA damage was measured on the basis of the decreased fluorescence intensity after binding the DNA with ethidium bromide. All the experiments used $^{60}Co$ gamma radiation at 1,252 Gy, representing 50% DNA damage. When increasing the concentration of ${\gamma}-PGA$ from 0.33 to $1.65{\mu}M$, the DNA protection from radiation-induced damage also increased, with a maximum of 87% protection. Meanwhile, the maximal DNA protection when increasing the concentration of GSH was only 70%. Therefore, ${\gamma}-PGA$ exhibited significant radioprotective effects against gamma irradiation.

Radiation Protective Effect of vitamin C and Cysteine on DNA Damage in Mice Splenic Lymphocytes by Single Cell Gel Electrophoresis Assay (단세포 겔 전기영동법을 이용한 생쥐 비장 림프구 DNA 손상에 대한 비타민 C 및 시스테인의 방사선 방어효과)

  • 천기정;김진규;김봉희
    • Environmental health and toxicology
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    • v.16 no.1
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    • pp.17-20
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    • 2001
  • The alkaline comet assay, employing a single-cell gel electrophoresis(SCGE), is a rapid, simple and sensitive technique for visualizing and measuring DNA damage leading to strand breakage in individual mammalian cells. The protecting effect of pretreatment with vitamin C and cysteine on the DNA damage of gamma ray was investigated in mice splenic lymphocytes. Vitamin C and cysteine were administered orally for five consecutive days before irradiation. Four week old ICR male mice were irradiated wish 3.5Gy of γ-radiation and were sacrificed 3 days later. Spleens were taken for DNA damage examination by Comet assay and the tail moments of DNA single -strand breaks in tole splenic lymphocytes were evaluated. The results show that pretreatment with vitamin C and cysteine were effective in protecting against DNA damage by gamma ray. Administration of antioxidants like vitamin C and cysteine to mice before irradiation was effective in reducing the tail moment of splenic lymphocytes DNA.

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The DNA Damage by Linoleic Acid Hydroperoxide (Linoleic acid과산화물의 DNA 손상작용)

  • KIM Seon-Bong;KANG Jin-Hoon;BYUN Han-Seok;KIM In-Soo;PARK Yeung-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.20 no.6
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    • pp.569-572
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    • 1987
  • The DNA damage by linoleic acid hydroperoxide (LHPO) was investigated in a DNA-LHPO system at $37^{\circ}C$ to elucidate the DNA damage mechanism by lipid peroxidation products. LHPO shelved a great DNA damage with the increase of its concentrations. DNA was completely damaged in a LHPO-DNA(weight ratio, 2:3) system after incubation for 2 days. The degree of DNA ,damage by LHPO was greated than that of linoleic acid. In the quantitative analysis of DNA damage, the decreasing ratio of DNA content was $60\%$ in $84{\mu}g$ LHPO system incubated for 1 day compared to the control solution marked $30\%$. There were no participation of active oxygens on the DNA damage by LHPO.

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