Dependence of the Yield of Strand Breaks Induced by γ-rays in DNA on the Physical Conditions of Exposure: Water Content and Temperature

Ito, Takashi; Baker, S.C.; Stickley, C.D.; Peak, Jennifer G.; Peak, Meyrick J.

doi:10.1080/09553009314550391

Cited by 90 publications

(69 citation statements)

References 21 publications

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“…It is usually accepted 1,2,3,4,5,6,7 that the detrimental biological effects of ionizing radiation, such as X-and γ-rays, are largely caused by damage to the DNA of living cells. This damage is classified as direct and indirect.…”

Section: Introductionmentioning

confidence: 99%

Soft X-ray and Low Energy Electron-Induced Damage to DNA under N₂ and O₂ Atmospheres

et al. 2011

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DNA damage induced by low energy electrons (LEEs) and soft X-rays is measured under dry nitrogen and oxygen at atmospheric pressure and temperature. Five-monolayer plasmid DNA films deposited on tantalum and glass substrates are exposed to Al K α X-rays of 1.5 keV in the two different environments. From the damage yields for DNA, G-values are extracted for X-rays and LEEs. The G values for LEEs are 3.5 and 3.4 higher than those for X-ray photons under N 2 and O 2 atmospheres, respectively. Since most of the measured damage is in the form of single strand breaks (SSB), this result indicates a much higher effectiveness for LEEs relative to X-rays in causing SSB in both environments. The results indicate that the oxygen fixation mechanism, which is highly effective in increasing radiobiological effectiveness, under aerobic conditions, is operative on the type of damage created at the early stage of DNA radiolysis by LEEs.

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Section: Introductionmentioning

confidence: 99%

Soft X-ray and Low Energy Electron-Induced Damage to DNA under N₂ and O₂ Atmospheres

et al. 2011

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“…In some experiments SSB yields are significantly increased by the inclusion of a water environment [136,143], so it seems confusing that SSB barriers can be so much higher than in gas phase. The barriers being calculated, however, are reliant on predictions made in the gas phase.…”

Section: Double Strandsmentioning

confidence: 99%

Interactions between low energy electrons and DNA: a perspective from first-principles simulations

Kohanoff¹,

McAllister²,

Tribello³

et al. 2017

J. Phys.: Condens. Matter

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Abstract. DNA damage caused by irradiation has been studied for many decades. Such studies allow us to better assess the dangers posed by radiation, and to increase the efficiency of the radiotherapies that are used to combat cancer. A full description of the irradiation process involves multiple size and time scales. It starts from the interaction of radiation -either photons or swift ions -with the biological medium. Such interactions cause electronic excitation and ionisation. The two main products of ionising radiation are thus electrons and radicals. Both of these species can cause damage to biological molecules, in particular DNA. In the long run, this molecular level damage can prevent cells from replicating and can hence lead to cell death. For a long time it was assumed that the main actors in the damage process were the radicals. However, experiments in a seminal paper by the group of Leon Sanche in 2000 showed that low-energy electrons (LEE), such as those generated when ionising biological targets, can also cause bond breaks in biomolecules, in particular strand breaks in plasmid DNA [1]. These results prompted a significant amount of experimental and theoretical work aimed at elucidating the role played by LEE in DNA damage.In this Topical Review we provide a general overview of the problem. We discuss experimental findings and theoretical results hand in hand with the aim of describing the physics and chemistry that occurs during the process of radiation damage, from the initial stages of electronic excitation, through the inelastic propagation of electrons in the medium, the interaction of electrons with DNA, and the chemical end-point effects on DNA. A very important aspect of this discussion is the consideration of a realistic, physiological environment. The role played by the aqueous solution and the amino acids from the histones in chromatin must be considered. Moreover, thermal fluctuations must be incorporated when studying these phenomena. Hence, a special place in this Topical Review is occupied by our recent first-principles molecular dynamics simulations that address the issue of how the environment favours or prevents LEEs from causing damage to DNA. We finish by summarising the conclusions achieved so far, and by suggesting a number of possible directions for further study.

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“…Ionising radiation can damage DNA in a cell directly, 2,3 or it can excite molecules in the cellular surroundings. These excited state species can go on to interact with DNA strands and cause damage.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Interaction between Low-Energy Electrons and DNA Nucleotides in Aqueous Solution

McAllister

Smyth

et al. 2015

J. Phys. Chem. Lett.

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Reactions that can damage DNA have been simulated using a combination of molecular dynamics and density functional theory. In particular, the damage caused by the attachment of a low energy electron to the nucleobase. Simulations of anionic single nucleotides of DNA in an aqueous environment that was modelled explicitly have been performed. This has allowed us to examine the role played by the water molecules that surround the DNA in radiation damage mechanisms. Our simulations show that hydrogen bonding and protonation of the nucleotide by the water can have a significant effect on the barriers to strand breaking reactions. Furthermore, these effects are not the same for all four of the bases.

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Dependence of the Yield of Strand Breaks Induced by γ-rays in DNA on the Physical Conditions of Exposure: Water Content and Temperature

Cited by 90 publications

References 21 publications

Soft X-ray and Low Energy Electron-Induced Damage to DNA under N₂ and O₂ Atmospheres

Soft X-ray and Low Energy Electron-Induced Damage to DNA under N₂ and O₂ Atmospheres

Interactions between low energy electrons and DNA: a perspective from first-principles simulations

Understanding the Interaction between Low-Energy Electrons and DNA Nucleotides in Aqueous Solution

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Dependence of the Yield of Strand Breaks Induced by γ-rays in DNA on the Physical Conditions of Exposure: Water Content and Temperature

Cited by 90 publications

References 21 publications

Soft X-ray and Low Energy Electron-Induced Damage to DNA under N2 and O2 Atmospheres

Soft X-ray and Low Energy Electron-Induced Damage to DNA under N2 and O2 Atmospheres

Interactions between low energy electrons and DNA: a perspective from first-principles simulations

Understanding the Interaction between Low-Energy Electrons and DNA Nucleotides in Aqueous Solution

Contact Info

Product

Resources

About

Soft X-ray and Low Energy Electron-Induced Damage to DNA under N₂ and O₂ Atmospheres

Soft X-ray and Low Energy Electron-Induced Damage to DNA under N₂ and O₂ Atmospheres