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Su M, Lien J, Anilao A, Guo T. Enhanced Single-Strand Breaks of a Nucleic Acid by Gold Nanoparticles under X-ray Irradiation. J Phys Chem Lett 2023; 14:1214-1221. [PMID: 36716218 DOI: 10.1021/acs.jpclett.2c03885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The hydroxyl radical concentration-dependent yield of single-strand breaks (SSBs), obtained through correction of scavenging and hindrance effects caused by gold nanoparticles (AuNPs), for fluorophore- and quencher-labeled DNA on AuNPs was 10 times that of free DNA based on fluorescence measurements of X-ray-irradiated DNA on AuNPs. By comparing the fluorescence data that revealed the number of SSBs with the results of mass spectrometry measurements that detected the total damage to DNA, we found that SSBs dominated DNA damage for DNA on AuNPs whereas non-SSB damage dominated for free DNA. The yield of RNA SSBs under X-ray irradiation was similar to that of DNA in the presence of AuNPs, whereas free RNA was more resistive to radiation than DNA. These results indicated the enhanced SSBs were likely catalyzed through the conversion from nucleobase damage to SSBs by AuNPs. The outcome of this work impacts materials and environmental science, sensing, nanotechnology, biology, and medicine.
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Affiliation(s)
- Mengqi Su
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| | - Jennifer Lien
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| | - Auddy Anilao
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| | - Ting Guo
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
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2
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Wang K, Zhang W, Zhang X, Hu X, Chang S, Zhang H. Highly Sensitive Gold Nanoparticles-DNA Nanosensor for γ-Radiation Detection. ACS APPLIED MATERIALS & INTERFACES 2020; 12:42403-42409. [PMID: 32833430 DOI: 10.1021/acsami.0c12234] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
It is very important to control the ionizing radiation dose in radiation therapy, which depends on the accurate and rapid measurement of radiation. Herein, a novel and highly sensitive nanosensor for γ-radiation detection is constructed using single-stranded DNA sequences as radiation-sensitive material and gold nanoparticles (AuNPs) as a signal reporter. Well-dispersed AuNPs gradually aggregated at high salt concentration when the sensor was irradiated, and this change was quantified by the visible spectra and surface plasmon resonance spectra. The radiation nanosensor has excellent linearity in the dose range of 0-100 Gy under optimal conditions. This method is simple and fast, which provides a new path for the γ-radiation dosimeter and has potential applications in the assessment of radiation-induced biological effects.
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Affiliation(s)
- Kaikai Wang
- College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211100, China
| | - Wei Zhang
- College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211100, China
| | - Xiaohong Zhang
- College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211100, China
| | - Xiaodan Hu
- College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211100, China
| | - Shuquan Chang
- College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211100, China
| | - Haiqian Zhang
- College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211100, China
- Jiangsu Key Laboratory for Biomaterials and Devices, Southeast University, Nanjing 210096, China
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3
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Forster JC, Douglass MJJ, Phillips WM, Bezak E. Monte Carlo Simulation of the Oxygen Effect in DNA Damage Induction by Ionizing Radiation. Radiat Res 2018; 190:248-261. [PMID: 29953346 DOI: 10.1667/rr15050.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
DNA damage induced by ionizing radiation exposure is enhanced in the presence of oxygen (the "oxygen effect"). Despite its practical importance in radiotherapy, the oxygen effect has largely been excluded from models that predict DNA damage from radiation tracks. A Monte Carlo-based algorithm was developed in MATLAB software to predict DNA damage from physical and chemical tracks through a cell nucleus simulated in Geant4-DNA, taking into account the effects of cellular oxygenation (pO2) on DNA radical chemistry processes. An initial spatial distribution of DNA base and sugar radicals was determined by spatially clustering direct events (that deposited at least 10.79 eV) and hydroxyl radical (•OH) interactions. The oxygen effect was modeled by increasing the efficiency with which sugar radicals from direct-type effects were converted to strand breaks from 0.6 to 1, the efficiency with which sugar radicals from the indirect effect were converted to strand breaks from 0.28 to 1 and the efficiency of base-to-sugar radical transfer from •OH-mediated base radicals from 0 to 0.03 with increasing pO2 from 0 to 760 mmHg. The DNA damage induction algorithm was applied to tracks from electrons, protons and alphas with LET values from 0.2 to 150 keV/μm under different pO2 conditions. The oxygen enhancement ratio for double-strand break induction was 3.0 for low-LET radiation up to approximately 15 keV/μm, after which it gradually decreased to a value of 1.3 at 150 keV/μm. These values were consistent with a range of experimental data published in the literature. The DNA damage yields were verified using experimental data in the literature and results from other theoretical models. The spatial clustering approach developed in this work has low memory requirements and may be suitable for particle tracking simulations with a large number of cells.
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Affiliation(s)
- Jake C Forster
- a Department of Physics, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia.,b Department of Medical Physics, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia 5000, Australia
| | - Michael J J Douglass
- a Department of Physics, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia.,b Department of Medical Physics, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia 5000, Australia
| | - Wendy M Phillips
- a Department of Physics, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia.,b Department of Medical Physics, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia 5000, Australia
| | - Eva Bezak
- a Department of Physics, University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia.,c Cancer Research Institute and School of Health Sciences, University of South Australia, Adelaide, South Australia, Australia
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Mallepu R, Potlapally L, Gollapalli VL. Photo-oxidation of some flavonoids with photochemically generated t-BuO •radicals in a t-BuOH water system using a kinetic approach. J CHIN CHEM SOC-TAIP 2018. [DOI: 10.1002/jccs.201700342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Radhika Mallepu
- Department of Chemistry, University College of Science; Osmania University; Hyderabad India
| | - Laxmi Potlapally
- Department of Pharmacy, University College of Technology; Osmania University; Hyderabad India
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Tehrani ZA, Javan MJ, Fattahi A, Hashemi MM. Structures, stabilities & conformational behaviors of hydrogen-atom abstractions of cytosine nucleosides: AIM & NBO analysis. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2011.05.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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6
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Kryston TB, Georgiev AB, Pissis P, Georgakilas AG. Role of oxidative stress and DNA damage in human carcinogenesis. Mutat Res 2011; 711:193-201. [DOI: 10.1016/j.mrfmmm.2010.12.016] [Citation(s) in RCA: 644] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 12/22/2010] [Accepted: 12/31/2010] [Indexed: 04/08/2023]
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7
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Yokoya A, Shikazono N, Fujii K, Noguchi M, Urushibara A. A novel technique using DNA denaturation to detect multiply induced single-strand breaks in a hydrated plasmid DNA molecule by X-ray and 4He2+ ion irradiation. RADIATION PROTECTION DOSIMETRY 2011; 143:219-225. [PMID: 21186218 DOI: 10.1093/rpd/ncq540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
To detect multiple single-strand breaks (SSBs) produced in plasmid DNA molecules by direct energy deposition from radiation tracks, we have developed a novel technique using DNA denaturation by which irradiated DNA is analysed as single-strand DNA (SS-DNA). The multiple SSBs that arise in both strands of DNA, but do not induce a double-strand break, are quantified as loss of SS-DNA using agarose gel electrophoresis. We have applied this method to X-ray and (4)He(2+) ion-irradiated samples of fully hydrated pUC18 plasmid DNA. The fractions of both SS-DNA and closed circular DNA (CC-DNA) exponentially decrease with the increasing dose of X rays and (4)He(2+) ions. The efficiency of the loss of SS-DNA was half that of CC-DNA for both types of irradiation, indicating that one of two strands in DNA is not broken when one SSB is produced in CC-DNA by irradiation. Contrary to our initial expectation, these results indicate that SSBs are not multiply induced even by high linear energy transfer radiation distributed in both strands.
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Affiliation(s)
- Akinari Yokoya
- Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai-mura, Ibaraki 319-1195, Japan.
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8
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Grills DC, Cook AR, Fujita E, George MW, Preses JM, Wishart JF. Application of external-cavity quantum cascade infrared lasers to nanosecond time-resolved infrared spectroscopy of condensed-phase samples following pulse radiolysis. APPLIED SPECTROSCOPY 2010; 64:563-570. [PMID: 20537222 DOI: 10.1366/000370210791414344] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Pulse radiolysis, utilizing short pulses of high-energy electrons from accelerators, is a powerful method for rapidly generating reduced or oxidized species and other free radicals in solution. Combined with fast time-resolved spectroscopic detection (typically in the ultraviolet/visible/near-infrared), it is invaluable for monitoring the reactivity of species subjected to radiolysis on timescales ranging from picoseconds to seconds. However, it is often difficult to identify the transient intermediates definitively due to a lack of structural information in the spectral bands. Time-resolved vibrational spectroscopy offers the structural specificity necessary for mechanistic investigations but has received only limited application in pulse radiolysis experiments. For example, time-resolved infrared (TRIR) spectroscopy has only been applied to a handful of gas-phase studies, limited mainly by several technical challenges. We have exploited recent developments in commercial external-cavity quantum cascade laser (EC-QCL) technology to construct a nanosecond TRIR apparatus that has allowed, for the first time, TRIR spectra to be recorded following pulse radiolysis of condensed-phase samples. Near single-shot sensitivity of DeltaOD <1 x 10(-3) has been achieved, with a response time of <20 ns. Using two continuous-wave EC-QCLs, the current apparatus covers a probe region from 1890-2084 cm(-1), and TRIR spectra are acquired on a point-by-point basis by recording transient absorption decay traces at specific IR wavelengths and combining these to generate spectral time slices. The utility of the apparatus has been demonstrated by monitoring the formation and decay of the one-electron reduced form of the CO(2) reduction catalyst, [Re(I)(bpy)(CO)(3)(CH(3)CN)](+), in acetonitrile with nanosecond time resolution following pulse radiolysis. Characteristic red-shifting of the nu(CO) IR bands confirmed that one-electron reduction of the complex took place. The availability of TRIR detection with high sensitivity opens up a wide range of mechanistic pulse radiolysis investigations that were previously difficult or impossible to perform with transient UV/visible detection.
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Affiliation(s)
- David C Grills
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
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9
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Vijayalakshmi G, Adinarayana M, Rao PJ, Kumara MN, Bhadregowda DG, Rangappa KS. Retracted: Kinetics of oxidation of adenosine by tert-butoxyl radical: protection and repair by chlorogenic acid. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10
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Rao PJ, Bothe E, Schulte-Frohlinde D. Reaction of Dithiothreitol and Para-nitroacetophenone with Different Radical Precursors of .OH Radical-induced Strand Break Formation of Single-stranded DNA in Anoxic Aqueous Solution. Int J Radiat Biol 2009; 61:577-91. [PMID: 1349622 DOI: 10.1080/09553009214551391] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The yields of single-strand breakage (ssb) in single-stranded calf thymus DNA (ssDNA) have been determined after 60Co gamma-irradiation of aqueous anoxic solutions in the presence of different concentrations of dithiothreitol (DTT), ascorbate or trans-4,5-dihydroxy-1,2-dithiane, using low-angle laser light scattering. The influence of DTT on the kinetics of ssb formation has been determined by conductivity measurements in pulse radiolysis. The results suggest that strand breakage in ssDNA proceeds via two modes of about equal contribution and with half-lives of about 7 ms and 0.8s, respectively. Both modes reflect reactions of at least two DNA radicals, which react with DTT by hydrogen-atom transfer reactions with similar rate constants of about 5-9 x 10(5) dm3 mol-1 s-1. These hydrogen-atom transfer reactions inhibit strand break formation. The slow mode is shown to represent the decay of base-radicals to generate sugar radicals. The involvement of the oxidizing .OH adduct radical of guanine in the formation of strand breaks can be ruled out and there is no evidence for a contribution from the anion or radical anion of DTT to the inhibition of strand breaks via electron transfer reactions to DNA radicals.
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Affiliation(s)
- P J Rao
- Max-Planck-Institut für Strahlenchemie, Mülheim a.d. Ruhr, Germany
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11
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Sharma GK, Madhava Rao BS, O'Neill P. Redox dependence of the reaction of alpha-alkoxyalkyl radicals with a series of oxidants. J Phys Chem B 2009; 113:2207-11. [PMID: 19178166 DOI: 10.1021/jp807994b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxygen and oxidants enhance the sensitivity of cells to radiation. To understand this effect at the mechanistic level, the redox dependences for the reactivity of weakly reducing alpha-monoalkoxyalkyl radicals of 1,4-dioxane and tetrahydrofuran with a series of oxidants, for example, quinones, viologens, and nitro-arenes, with one-electron reduction potentials E71 values ranging from -80 to -640 mV, have been determined using the technique of pulse radiolysis. The second-order rate constants for these reactions with the alpha-monoalkoxyalkyl radicals of 1,4-dioxane and tetrahydrofuran are in the range (0.03-1.5) x 109 and (1.0-6.6) x 109 dm3 mol(-1) s(-1), respectively. The reactions of the alpha-alkoxyalkyl radicals of 1,4-dioxane with quinones and viologens involve an outer-sphere electron transfer, in contrast to a reaction with the nitro-arenes to give adducts. The resulting long-lived nitroaromatic adduct radicals were found to react with the reductant, TMPD, probably leading to the formation of hydroxylamine-type products. In cells, adducts formed on reaction of deoxyribose sugar radical with oxidants and subsequent reactions with reductants may contribute to the mechanisms involved in radiosensitization by oxygen and those oxidants that interact through adduct formation.
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Affiliation(s)
- Geeta K Sharma
- Gray Institute for Radiation Oncology and Biology, University of Oxford, ORCRB, Roosevelt Drive, Oxford, OX3 7DQ, UK
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12
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Liu Z, Lin H, Ye S, Liu QY, Meng Z, Zhang CM, Xia Y, Margoliash E, Rao Z, Liu XJ. Remarkably high activities of testicular cytochrome c in destroying reactive oxygen species and in triggering apoptosis. Proc Natl Acad Sci U S A 2006; 103:8965-70. [PMID: 16757556 PMCID: PMC1482549 DOI: 10.1073/pnas.0603327103] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hydrogen peroxide (H(2)O(2)) is the major reactive oxygen species (ROS) produced in sperm. High concentrations of H(2)O(2) in sperm induce nuclear DNA fragmentation and lipid peroxidation and result in cell death. The respiratory chain of the mitochondrion is one of the most productive ROS generating systems in sperm, and thus the destruction of ROS in mitochondria is critical for the cell. It was recently reported that H(2)O(2) generated by the respiratory chain of the mitochondrion can be efficiently destroyed by the cytochrome c-mediated electron-leak pathway where the electron of ferrocytochrome c migrates directly to H(2)O(2) instead of to cytochrome c oxidase. In our studies, we found that mouse testis-specific cytochrome c (T-Cc) can catalyze the reduction of H(2)O(2) three times faster than its counterpart in somatic cells (S-Cc) and that the T-Cc heme has the greater resistance to being degraded by H(2)O(2). Together, these findings strongly imply that T-Cc can protect sperm from the damages caused by H(2)O(2). Moreover, the apoptotic activity of T-Cc is three to five times greater than that of S-Cc in a well established apoptosis measurement system using Xenopus egg extract. The dramatically stronger apoptotic activity of T-Cc might be important for the suicide of male germ cells, considered a physiological mechanism that regulates the number of sperm produced and eliminates those with damaged DNA. Thus, it is very likely that T-Cc has evolved to guarantee the biological integrity of sperm produced in mammalian testis.
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Affiliation(s)
- Zhe Liu
- *Institute of Biomedical Informatics, School of Medicine, and
- MOE Laboratory of Protein Science and Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China
| | - Hao Lin
- *Institute of Biomedical Informatics, School of Medicine, and
- State Key Laboratory of Biomembrane and Membrane Biotechnology, College of Life Sciences, Peking University, Beijing 100871, China; and
| | - Sheng Ye
- MOE Laboratory of Protein Science and Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China
| | - Qin-ying Liu
- State Key Laboratory of Biomembrane and Membrane Biotechnology, College of Life Sciences, Peking University, Beijing 100871, China; and
| | - Zhaohui Meng
- MOE Laboratory of Protein Science and Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China
| | - Chuan-mao Zhang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, College of Life Sciences, Peking University, Beijing 100871, China; and
| | - Yongjing Xia
- *Institute of Biomedical Informatics, School of Medicine, and
| | - Emanuel Margoliash
- Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, IL 60208
- To whom correspondence may be addressed. E-mail:
, , or
| | - Zihe Rao
- MOE Laboratory of Protein Science and Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China
- To whom correspondence may be addressed. E-mail:
, , or
| | - Xiang-jun Liu
- *Institute of Biomedical Informatics, School of Medicine, and
- To whom correspondence may be addressed. E-mail:
, , or
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13
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Mechanism of protection of adenosine from sulphate radical anion and repair of adenosine radicals by caffeic acid in aqueous solution. J CHEM SCI 2005. [DOI: 10.1007/bf02708449] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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14
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Charitha L, Adinarayana M. Kinetics of oxidation of adenosine byt-butoxyl radical: Protection and repair by caffeic acid. INT J CHEM KINET 2005. [DOI: 10.1002/kin.20106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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15
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Swaraga MS, Adinarayana M. Kinetics and mechanism of protection of thymine from sulphate radical anion under anoxic conditions. J CHEM SCI 2003. [DOI: 10.1007/bf02716979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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16
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Mori M, Teshima SI, Yoshimoto H, Fujita SI, Taniguchi R, Hatta H, Nishimoto SI. OH Radical Reaction of 5-Substituted Uracils: Pulse Radiolysis and Product Studies of a Common Redox-Ambivalent Radical Produced by Elimination of the 5-Substituents. J Phys Chem B 2001. [DOI: 10.1021/jp002989h] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mayuko Mori
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Research Institute of Advanced Technology, University of Osaka Prefecture, Osaka 599-8231, Japan
| | - Sei-ichi Teshima
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Research Institute of Advanced Technology, University of Osaka Prefecture, Osaka 599-8231, Japan
| | - Hideaki Yoshimoto
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Research Institute of Advanced Technology, University of Osaka Prefecture, Osaka 599-8231, Japan
| | - Shin-ichi Fujita
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Research Institute of Advanced Technology, University of Osaka Prefecture, Osaka 599-8231, Japan
| | - Ryoichi Taniguchi
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Research Institute of Advanced Technology, University of Osaka Prefecture, Osaka 599-8231, Japan
| | - Hiroshi Hatta
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Research Institute of Advanced Technology, University of Osaka Prefecture, Osaka 599-8231, Japan
| | - Sei-ichi Nishimoto
- Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Research Institute of Advanced Technology, University of Osaka Prefecture, Osaka 599-8231, Japan
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17
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Kumar MR, Adinarayana M. Kinetics and mechanism of protection of thymine from phosphate radical anion under anoxic conditions. INT J CHEM KINET 2001. [DOI: 10.1002/kin.1020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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von Sonntag C, Schuchmann HP. Carbohydrates. RADIATION CHEMISTRY - PRESENT STATUS AND FUTURE TRENDS 2001. [DOI: 10.1016/s0167-6881(01)80020-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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19
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Application of Molecular Orbital Theory to the Elucidation of Radical Processes Induced by Radiation Damage to DNA. ACTA ACUST UNITED AC 1999. [DOI: 10.1016/s1380-7323(99)80082-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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20
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Bamatraf MMM, O'Neill P, Rao BSM. Redox Dependence of the Rate of Interaction of Hydroxyl Radical Adducts of DNA Nucleobases with Oxidants: Consequences for DNA Strand Breakage. J Am Chem Soc 1998. [DOI: 10.1021/ja9823161] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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21
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Melvin T, Bothe E, Schulte-Frohlinde D. The reaction of triplet 2-methyl-1,4-naphthoquinone (menadione) with DNA and polynucleotides. Photochem Photobiol 1996; 64:769-76. [PMID: 8931374 DOI: 10.1111/j.1751-1097.1996.tb01833.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The photoreaction of 2-methyl-1,4-naphthoquinone (MQ, menadione) with DNA and polynucleotides in argon-saturated aqueous solution (pH 7) was studied. Results from laser flash photolysis experiments indicate that triplet quinone reacts with DNA and polyA but not detectably with polyU by one-electron oxidation of the bases of the nucleic acid with formation of the radical anion of the quinone. Irradiation of argon-saturated solutions containing MQ and DNA or polynucleotides (polyU, polyA, polyG or polyC) with 334 nm light leads to an increase in molecular weight for single-stranded DNA, polyA and to a much less extent for polyU. This finding indicates crosslink formation with quantum yields in the range of 10(-5)-10(-3).
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Affiliation(s)
- T Melvin
- Max-Planck-Institut für Strahlenchemie, Mülheim an der Ruhr, Germany.
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22
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Gorner H, Currell LJ. Transient conductivity OF 1,3-dimethyluracil, uridine and 3-methyluridine in aqueous solution following 20-ns laser excitation at 248 nm. Radiat Phys Chem Oxf Engl 1993 1996. [DOI: 10.1016/0969-806x(95)00456-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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23
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Tossi AB, Sun L, Görner H, Schulte-Frohlinde D. Inhibition of OH radical-induced strand break formation of poly(U) by Ru(bpy)32+ or Ru(phen)32+ attached to the polynucleotide. Int J Radiat Biol 1995; 68:525-33. [PMID: 7490502 DOI: 10.1080/09553009514551511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Reactions of OH radicals with poly(U) (polyuridylic acid) in the presence of Ru(bpy)32+ or Ru(phen)32+ in aqueous solutions were studied. OH radicals were produced by pulse radiolysis and their reactions with ruthenium complexes were measured spectrophotometrically under conditions were the complexes are attached to the polynucleotide. The OH radical adds to either the uracil moiety or the ruthenium complexes. The ratio of the radicals produced depends only on the ratio of their rate constants and the concentrations of poly(U) and ruthenium complexes. Similar results were obtained with uridine-5'-monosphosphate, where the ruthenium complexes are not attached to the nucleotide. Surprisingly, the yield of single-strand break formation from the OH adducts of uracil in poly(U) is much smaller than that expected on the basis of the yield measured in the absence of ruthenium complexes. Possible reasons for this behaviour are discussed.
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Affiliation(s)
- A B Tossi
- Max-Planck-Institut für Strahlenchemie, Mülheim, Ruhr, Germany
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Grachev SA, Kropachev EV, Litvjakova GI. Formation of 5-hydroxy-5,6-dihydrouracil and release of undamaged uracil as a result of poly(U) irradiation in N2O-saturated aqueous solution. Int J Radiat Biol 1995; 68:543-51. [PMID: 7490504 DOI: 10.1080/09553009514551531] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The radiation chemical yields of 5-hydroxy-5,6-dihydrouracil and uracil were measured on radiolysis of N2O-saturated solutions containing I mmol dm-3 poly(U) and were found to be 0.04 and 0.31 mumol J-1 respectively. From the 5-hydroxy-5,6-dihydrouracil yield in the presence of cysteamine and 2-mercaptoethanol, it is shown that only 20% of the OH-radicals, which attack poly(U) results in the formation of 5-hydroxy uracil adducts. It has been proposed that as yet unknown reducing radicals are formed in addition to known reducing radicals (the 5-OH-adducts of uracil, the H-adducts of uracil, and sugar radicals) as a result of the reaction of OH-radicals with poly(U).
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Affiliation(s)
- S A Grachev
- St Petersburg Nuclear Physics Institute, Russian Academy of Sciences, Russia
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25
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The enhanced stability of the cross-linked hylan structure to hydroxyl (OH) radicals compared with the uncross-linked hyaluronan. Radiat Phys Chem Oxf Engl 1993 1995. [DOI: 10.1016/0969-806x(95)00015-p] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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26
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Testereci HN, Usanmaz A, Önal AM. Viscosity Molecular Weight Determination of Polyadenylic Acid. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 1995. [DOI: 10.1080/10601329508013683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- H. Nur Testereci
- a Department of Chemistry
- c Department of Chemistry , Kìrìkkale University , Kìrìkkale , Turkey
| | | | - Ahmet M. Önal
- b Department of Science Education , Middle East Technical University , Ankara , Turkey
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27
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Testereci H, Usanmaz A, Önal A. Studies on the strand-breaking activity of the ascorbate/copper(ii) system in poly(adenylic acid). POLYMER 1995. [DOI: 10.1016/0032-3861(95)94346-u] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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28
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Görner H. Photochemistry of DNA and related biomolecules: quantum yields and consequences of photoionization. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1994; 26:117-39. [PMID: 7815187 DOI: 10.1016/1011-1344(94)07068-7] [Citation(s) in RCA: 151] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The reactions of nucleic acids and constituents, which can be induced by laser UV irradiation, are described. Emphasis is placed on the quantum yields of various stable photoproducts of DNA and model compounds upon irradiation at 193, 248, 254 or 266 nm. In particular, those quantum yields and processes are discussed which involve photoionization as the initial step and occur in aqueous solution under well defined conditions, e.g. type of atmosphere. The efficiencies of some photoproducts, with respect to photoionization using irradiation at 193 or 248 nm, are presented. Radical cations of nucleobases are important sources of damage of biological substrates since they can cause lesions other than dimers and adducts, e.g. strand breakage, abasic sites, crosslinks or inactivation of plasmid and chromosomal DNA. While competing photoreactions, such as hydration, dimerization or adduct formation, diminish the selectivity of the photoionization method, a combination with model studies on pyrimidine- and purine-containing constituents of DNA has brought about an enhanced insight into the reaction mechanisms. The knowledge concerning the lethal events in plasmid and cellular DNA has been greatly improved by correlation with the chemical effects obtained by gamma-radiolysis, vacuum-UV (< 190 nm) and low-intensity irradiation at 254 nm.
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Affiliation(s)
- H Görner
- Max-Planck-Institut für Strahlenchemie, Germany
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29
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Bothe E, Janata E. Instrumentation of kinetic spectroscopy—13. a.c.-conductivity measurements at different frequencies in kinetic experiments. Radiat Phys Chem Oxf Engl 1993 1994. [DOI: 10.1016/0969-806x(94)90040-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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30
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Melvin T, O'Neill P, Jones GD. Influence of nucleic acid base composition on radiation-induced strand breakage in single stranded DNA: a time resolved study. Int J Radiat Biol 1994; 66:499-503. [PMID: 7983437 DOI: 10.1080/09553009414551521] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The following study investigates the pathways involved in the induction of single strand breaks (ssb) in various samples of single stranded (ss) DNA (calf thymus, Micrococcus lysodeikticus, Clostridium perfringens) with differing nucleic acid base composition. The time scale for the induction of ssb was determined from changes in the light scattering intensity following pulse irradiation of aqueous solutions containing these ssDNA samples at pH7.8 under either aerated or deaerated conditions. The induction of ssb under these conditions is predominantly by the hydroxyl radical and shows various kinetically distinct components. The immediate ssb (t < 0.02 s) account for approximately 40-60% of the total yield of ssb. The majority of these ssb are suggested to arise from the 'common' initial attack of the hydroxyl radicals at the sugar phosphate backbone for each of the three DNA samples. Furthermore, slower components for ssb formation (t > 0.02 s) were observed and are suggested to occur through base radical mediated H-atom abstraction from the sugar moiety. The half lives for formation of the majority of ssb, formed through this base radical-mediated H-atom abstraction(s), are in the range of 20-43 ms. The yields of these 'base-mediated' ssb vary markedly (under both aerobic and anaerobic conditions) and reflect the base composition of the DNA sample. It is suggested from these studies that the OH-induced base radicals of guanine/cytosine are more effective precursors for strand breakage than those from adenine/thymine in ssDNA.
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Affiliation(s)
- T Melvin
- Cross Cancer Institute, Edmonton, Alberta, Canada
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31
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Gurzadyan GG, Görner H. Damage to uracil- and adenine-containing bases, nucleosides, nucleotides and polynucleotides: quantum yields on irradiation at 193 and 254 nm. Photochem Photobiol 1994; 60:323-32. [PMID: 7991661 DOI: 10.1111/j.1751-1097.1994.tb05111.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Photoreactions, such as base release and decomposition of the base moiety, induced by either 20 ns laser pulses at 193 nm or continuous 254 nm irradiation, were studied for a series of uracil and adenine derivatives in neutral aqueous solution. The quantum yield of chromophore loss (phi cl) depends significantly on the nature of the nucleic acid constituent and the saturating gas (Ar, N2O or O2). In the case of polynucleotides the destruction of nucleotides was measured by high-performance liquid chromatography after hydrolysis; the quantum yields (phi dn) are comparable to those of chromophore loss or larger. The phi cl and phi dn of 0.04-0.1 for poly(U) and poly(dU), obtained for both wavelengths of irradiation, are due to processes originating from the lowest excited singlet state, i.e. formation of photohydrates and photodimers, and a second part from photoionization using lambda irr = 193 nm. Irradiation at 193 nm effectively splits pyrimidine dimers and thus reverts them into monomers. The quantum yield for release of undamaged bases (phi br) from nucleosides, nucleotides and polynucleotides upon irradiation at 254 nm is typically phi br = (0.1-1) x 10(-4). Breakage of the N-glycosidic bond is significantly more efficient for lambda irr = 193 nm, e.g. phi br = 1.1 x 10(-3), 0.8 x 10(-3), 4.3 x 10(-3) and 0.5 x 10(-3) for poly(A), poly(dA), poly(U) and poly(dU) in Ar-saturated solution, respectively. Enhanced phi values for lambda irr = 193 nm, essentially for adenine and its derivatives, are caused by photoprocesses that are initiated by photoionization.
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Affiliation(s)
- G G Gurzadyan
- Max Planck Institut für Strahlenchemie, Mülheim an der Ruhr, Germany
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32
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33
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Paillous N, Vicendo P. Mechanisms of photosensitized DNA cleavage. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 1993. [DOI: 10.1016/1011-1344(93)80152-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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34
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Wolf P, Jones GD, Candeias LP, O'Neill P. Induction of strand breaks in polyribonucleotides and DNA by the sulphate radical anion: role of electron loss centres as precursors of strand breakage. Int J Radiat Biol 1993; 64:7-18. [PMID: 8102172 DOI: 10.1080/09553009314551061] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The interaction of the sulphate radical anion, SO4.-, with the polyribonucleotides, poly U and poly C, in deaerated, aqueous solutions at pH 7.5 results in strand breakage (sb) with efficiencies of 57 and 23%, respectively, determined by time resolved laser light scattering (TRLS). Most sb are produced within 70 microseconds, the risetime of the detection system. Oxygen inhibits the induction of sb in poly U and poly C by SO4.- through its interaction with a radical precursor to sb. In contrast, the interaction of SO4.- with poly A and single stranded DNA does not lead to significant strand breakage (< or = 5% efficiency). From optical studies, the interaction of poly A and poly G with SO4.- radicals yields predominantly the corresponding one electron oxidized base radicals. With poly C and poly U, it is proposed that the SO4.- radical interacts predominantly by addition to the base moiety to produce the C(5)-yl and C(6)-yl sulphate radical adducts which react with oxygen. These base adducts subsequently interact with the sugar-phosphate moiety by H-atom abstraction to yield C(2)' sugar radicals with rate constants in the range 1.3-1.7 x 10(5) s-1. It is proposed that the C(2)' sugar radical leads to strand breakage within 70 microseconds, in competition with its transformation into the C(1)'-sugar radical involving base release. From optical studies on the interaction of SO4.- with double stranded DNA, it is suggested that the predominant radical species produced in DNA is the one-electron oxidized radical of guanine, consistent with positive charge migration in DNA. Since the efficiency of SO4.- to induce sb in single stranded DNA is low, it is concluded that the one-electron oxidized guanine radical does not effectively induce strand breakage in DNA.
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Affiliation(s)
- P Wolf
- Division of Radiobiological Mechanisms, MRC Radiobiology Unit, Chilton, Didcot, UK
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35
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Görner H, Gurzadyan GG. Photolysis of polycytidylic acid on 193 nm laser excitation. J Photochem Photobiol A Chem 1993. [DOI: 10.1016/1010-6030(93)85067-i] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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36
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37
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38
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Oxidation of nucleic acid bases by hexavalent manganese in aqueous alkaline medium: a kinetic study. TRANSIT METAL CHEM 1992. [DOI: 10.1007/bf02910902] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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39
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Görner H, Wala M, Schulte-Frohlinde D. Strand breakage in poly(C), poly(A), single- and double-stranded DNA induced by nanosecond laser excitation at 193 nm. Photochem Photobiol 1992; 55:173-84. [PMID: 1542699 DOI: 10.1111/j.1751-1097.1992.tb04225.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Single- and double-stranded calf thymus DNA and two polynucleotides (0.4 mM) were studied in aqueous solution at pH approximately 7 using pulsed, 20 ns laser excitation at 193 nm. Monophotonic ionization of the nucleic acids is suggested from the linear dependences of the concentration of ejected electrons and the number of single- and double-strand breaks (ssb, dsb, respectively) on laser intensity (IL) in the range (0.2-3) x 10(6) W cm-2. The quantum yields of formation of hydrated electrons (phi e-) and ssb and dsb (phi ssb and phi dsb) are therefore independent of IL. In contrast, under 248 nm excitation these quantum yields increase linearly with IL under otherwise comparable conditions. Nevertheless, several effects and mechanistic implications are analogous using lambda exc = 193 and 248 nm. For polycytidylic acid, poly(C), in Ar-saturated solution for example, the efficiency of ssb per radical cation (eta RC = phi ssb/phi e-) is similar to the efficiency of ssb per OH radical (eta OH). For polyadenylic acid, poly(A), and single- and double-stranded DNA eta RC (lambda exc = 193 nm) is significantly smaller than eta OH. The ratio phi ssb (N2O)/phi ssb (Ar) is approximately 2 for poly(C), approximately 4 for poly(A) approximately 10 for DNA; the conversion of hydrated electrons into OH radicals in N2O-saturated solution and smaller eta RC than eta OH values in the case of DNA account for these results. For double-stranded DNA phi dsb does not depend on IL but increases linearly with the dose, indicating an accumulative effect of two ssb to generate one dsb. The critical distance for this event is 60-85 phosphoric acid diester bonds.
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Affiliation(s)
- H Görner
- Max-Planck-Institut für Strahlenchemie, Mülheim an der Ruhr, Fed. Rep. Germany
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40
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von Sonntag C, Schuchmann HP. Aufklärung von Peroxyl-Radikalreaktionen in wäßriger Lösung mit strahlenchemischen Techniken. Angew Chem Int Ed Engl 1991. [DOI: 10.1002/ange.19911031006] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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41
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Jones GD, O'Neill P. Kinetics of radiation-induced strand break formation in single-stranded pyrimidine polynucleotides in the presence and absence of oxygen; a time-resolved light-scattering study. Int J Radiat Biol 1991; 59:1127-45. [PMID: 1675234 DOI: 10.1080/09553009114551031] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Time-resolved reductions in the light-scattering intensity (LSI) of aqueous oxic and anoxic solutions of poly-C and poly-U at pH 7.8, following pulse-irradiation, have been studied as indices of strand break formation. With doses of 3-24 Gy per pulse, a number of kinetically distinct strand breakage components have been detected. A comparison of the LSI responses obtained from irradiations conducted under N2O with those conducted under air or O2 show no marked difference in the overall extent of LSI change. However, the immediate and fast (t 1/2 less than or equal to 50 microseconds) reduction in LSI, accounting for about 18-19% of the pyrimidine polynucleotide's total LSI response in oxic solution, is reduced in the absence of oxygen, to about 12% of the total LSI response found with poly-C and to about 9% for poly-U. For poly-C there is a five-fold enhancement in the rate of major strand breakage under anoxia [k1(N2O) = 7.9s-1] whereas for poly-U a more modest enhancement (about two-fold) is observed. These enhanced rates are mirrored by those for the losses of the principal optical anoxic absorptions (observed pulse radiolytically) that are assigned to the pyrimidine 6-yl base radicals. Such findings support a proposal that the rate-limiting step of major strand breakage for pyrimidine polynucleotides is a base radical mediated hydrogen atom abstraction reaction (Lemaire et al. 1987, Hildenbrand and Schulte-Frohlinde 1989). Irradiation of poly-C and poly-U in N2O/O2 (4:1, v/v) saturated solutions yields LSI changes much larger than those noted under N2O and air (or O2), which are in turn approximately double the responses observed under N2. This indicates that the major strand breaking species of water radiolysis is the OH-radical and that there is an oxygen enhancement of single strand breakage of about 1.9 for poly-C and 1.6 for poly-U.
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Affiliation(s)
- G D Jones
- Division of Molecular Processes, Medical Research Council Radiobiology Unit, Didcot, Oxon, UK
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42
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Udovicić L, Mark F, Bothe E, Schulte-Frohlinde D. Non-homogeneous kinetics in the competition of single-stranded calf-thymus DNA and low-molecular weight scavengers for OH radicals: a comparison of experimental data and theoretical models. Int J Radiat Biol 1991; 59:677-97. [PMID: 1672357 DOI: 10.1080/09553009114550601] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The yield of single-strand breaks induced by 60Co gamma-radiation in single-stranded calf-thymus DNA has been measured in aqueous, N2O/O2 saturated DNA solutions as a function of the concentration of added OH scavengers. Single-strand break yields have also been determined, relative to the yield of OH radicals, using pulse radiolysis. Essentially the same dependence on scavenging capacity was obtained under both irradiation conditions. At the highest scavenging capacity used (approximately 10(9) s-1), about eight times more strand breaks are formed than would be predicted from homogeneous competition kinetics. The experimental data are compared with values obtained from theoretical models which are based on non-homogeneous kinetics, and include the effects of spurs and of the direct action of radiation. The comparison shows that the observed dependence of the single-strand break yield on the scavenging capacity can be quantitatively accounted for without the need of empirical adjustment of parameters using a DNA model where the macromolecules are approximated by structureless cylinders of radius Rc = 0.80 nm which on their surface react with OH radicals at a diffusion-controlled rate. The factors determining the scavenger dependence of the single-strand break yield are discussed. The increase on going to higher scavenging capacities in the apparent rate constant of the reaction of OH with DNA is rationalized in terms of the mean diffusion length of OH radicals in solution. Estimates are given for the fractions of strand breaks due to randomized OH radicals, OH radicals from spurs, and the direct radiation effect.
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Affiliation(s)
- L Udovicić
- Max-Planck-Institut für Strahlenchemie, Mülheim a.d.Ruhr, FRG
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43
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Osman R, Miaskiewicz K, Weinstein H. Structure-function relations in radiation damaged DNA. BASIC LIFE SCIENCES 1991; 58:423-47; discussion 447-52. [PMID: 1667352 DOI: 10.1007/978-1-4684-7627-9_16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- R Osman
- Department of Physiology and Biophysics, Mount Sinai School of Medicine, City University of New York
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44
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von Sonntag C. The chemistry of free-radical-mediated DNA damage. BASIC LIFE SCIENCES 1991; 58:287-317; discussion 317-21. [PMID: 1811474 DOI: 10.1007/978-1-4684-7627-9_10] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In the living cell, ionizing radiation can cause DNA damage by the direct effect (ionization of DNA) and the indirect effect (reaction of radicals formed in the neighborhood of DNA with DNA, e.g., OH, eaq-, H, protein- and glutathione-derived radicals). Properties of the base radical cations have been studied in model systems using SO4- radical to oxidize the nucleobases in aqueous solution. The pKa values of some nucleobase radical cations are reported, so are the ensuing reactions of the thymidine radical cation with water. The products of reactions are compared with those formed by OH radical attack. The reaction of eaq- with the nucleobases yields radical anions. Protonation at heteroatom sites and at carbon are discussed, and some recent results regarding the electron transfer to adjacent nucleobases as well as to 5-bromouracil are reported. A brief account is given on the reaction of carbon-centered radicals with the nucleobases. These reactions may mimic the reactions of protein-derived radicals with DNA. Glutathione is present in cells at rather high concentrations and is expected to act as an H- or electron-donor in repairing radiation-induced DNA damage (chemical repair). As thiyl radicals are known to also undergo the reverse reaction, i.e., H-abstraction from suitable solutes, some experiments are reported which probe this type of reaction with dilute DNA solutions. In some polynucleotides radical transfer from the base radical to the sugar moiety occurs with the consequence of strand breakage and base release. Some currently held mechanistic concepts are discussed. Attention is drawn to some important open questions which should be addressed in the near future.
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Affiliation(s)
- C von Sonntag
- Max-Planck-Institut für Strahlenchemie, Mülheim a.d. Ruhr, Germany
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45
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Deeble D, Randall R, Williams P, Phillips G, Akhlaq M, Puramshetty J, Bothe E, Steffen H, von Sonntag C. The treatment of aqueous gum arabic solutions with ultraviolet radiation. Food Hydrocoll 1990. [DOI: 10.1016/s0268-005x(09)80208-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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46
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Schulte-Frohlinde D, Simic MG, Görner H. Laser-induced strand break formation in DNA and polynucleotides. Photochem Photobiol 1990; 52:1137-51. [PMID: 2087501 DOI: 10.1111/j.1751-1097.1990.tb08453.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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47
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Bothe E, Görner H, Opitz J, Schulte-Frohlinde D, Siddiqi A, Wala M. Single- and double-strand break formation in double-stranded DNA upon nanosecond laser-induced photoionization. Photochem Photobiol 1990; 52:949-59. [PMID: 2287636 DOI: 10.1111/j.1751-1097.1990.tb01811.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Double-stranded (ds) calf thymus DNA (0.4 mM), excited by 20 ns laser pulses at 248 nm, was studied in deoxygenated aqueous solution at room temperature and pH 6.7 in the presence of a sodium salt (10 mM). The quantum yields for the formation of hydrated electrons (phi c-), single-strand breaks (phi ssb) and double-strand breaks (phi dsb) were determined for various laser pulse intensities (IL). phi c- and phi ssb increase linearly with increasing IL; however, phi ssb has a tendency to reach saturation at high IL (greater than 5 X 10(6) Wcm-2). The ratio phi ssb/phi c-, representing the number of ssb per radical cation, is about 0.08 at IL less than or equal to 5 X 10(6) Wcm-2. For comparison, the number of ssb per OH radical reacting with dsDNA is 0.22. On going from argon to N2O saturation, phi ssb and phi dsb become larger by factors of approximately 5 and 10-15, respectively. This enhancement is produced by attack on DNA bases by OH radicals generated by N2O-scavenging of the photoelectrons. While phi ssb is essentially independent of the dose (Etot), phi dsb depends linearly on Etot in both argon- and N2O-saturated solutions. The linear dependence of phi dsb implies a square dependence of the number of dsb on Etot. This portion of dsb formation is explained by the occurrence of two random ssb, generated within a critical distance (h) in opposite strands. For both argon- and N2O-saturated solutions h was found to be of the order of 40-70 phosphoric acid diester bonds. On addition of electron scavengers such as 2-chloroethanol (or N2O plus t-butanol), phi dsb is similar to that in neat, argon-saturated solutions. Thus, hydrated electrons are not involved in the chemical pathway leading to laser-pulse-induced dsb of DNA.
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Affiliation(s)
- E Bothe
- Max-Planck-Institut für Strahlenchemie, Mülheim an der Ruhr, W. Germany
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48
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Quantum yields for the generation of hydrated electrons and single-strand breaks in poly(C), poly(A) and single-stranded DNA in aqueous solution on 20 ns laser excitation at 248 nm. J Photochem Photobiol A Chem 1990. [DOI: 10.1016/1010-6030(90)87116-s] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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49
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Jones GD, O'Neill P. The kinetics of radiation-induced strand breakage in polynucleotides in the presence of oxygen: a time-resolved light-scattering study. Int J Radiat Biol 1990; 57:1123-39. [PMID: 1971839 DOI: 10.1080/09553009014551241] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The time-resolved light-scattering changes of aqueous, aerated solutions of poly-C, poly-U and poly-A at pH 7.8, following pulse irradiation, have been studied as indices of strand break formation. With doses of 4-24 Gy/pulse a number of kinetically distinct components have been detected. For the poly-pyrimidines an immediate and fast reduction (tau 1/2 less than or equal to 50 microseconds) in light-scattering intensity (LSI), accounting for approximately 20% of the total LSI change, is followed by a much slower loss (k1 approximately 1.6 s-1) which constitutes their major LSI change. For poly-A a similar fast component is observed, present to an extent equivalent to the one noted with poly-C; it constitutes, however, over 50% of the purine polynucleotide's total response, with the remainder of the change being a slower loss (tau 1/2 approximately 0.09 s). Optical pulse radiolysis studies of poly-C and poly-U, in support of the LSI investigations, show that transient absorbances in a region assigned to base peroxyl radicals decay in a complex fashion, with some at a rate equivalent to that for the slow (major) component of LSI loss. These observations support a proposal that the rate-limiting step of major strand breakage for these polynucleotides, in the presence of oxygen, is a base peroxyl radical-mediated abstraction of a H-atom from an adjacent sugar moiety (Bothe et al. 1986), with the resulting sugar peroxyl radicals then leading to strand break formation at a rate equivalent to that for loss of the initial, fast LSI components. These latter processes are attributed to strand breaks arising from the direct interaction of .OH with the polynucleotide sugar phosphate backbone.
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Affiliation(s)
- G D Jones
- Medical Research Council Radiobiology Unit, Chilton, Didcot, Oxon, UK
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50
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Abstract
The effects of fast neutron irradiation on DNA were studied using DNA of the pBR322 plasmid (4362 base pairs), and the results compared to those obtained with 60Co gamma rays. Irradiation of the plasmid DNA in solution with a neutrons beam (p34+Be) of the CERI (CNRS Orléans) cyclotron (with a flat energy spectrum from 34 MeV to low energies) results in half the yield of single-strand breaks (ssb), and 1.5 times higher yield of double-strand breaks (dsb) for neutrons as compared to gamma-rays. Possible specificity of the neutron-induced breaks was examined: the scavenging of OH. radicals by 0.1 mol dm-3 ethanol inhibits all neutron-induced ssb, but only 85 per cent of the dsb. For gamma-irradiation, both ssb and dsb are completely inhibited in these conditions. These results suggest at least three different origins for neutron-induced dsb. The occurrence of around 30 per cent of dsb can be explained by a radical transfer mechanism (proposed by Siddiqi and Bothe (1987) for gamma-irradiation). Around 55 per cent of dsb may be due to the non-random distribution of radicals in high-density tracks of the secondary particles of neutrons, which results in a simultaneous attack of the two strands by OH. radicals. These first two processes are both OH.-mediated and thus are sensitive to ethanol. The direct effect of fast neutrons and their secondaries (recoil protons, alpha-particles and recoil nuclei) can account for the remaining 15 per cent of dsb, not inhibited by 0.1 mol dm-3 ethanol.
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