Calculation on spectrum of direct DNA damage induced by low-energy electrons including dissociative electron attachment

Liu, Wei; Tan, Zhenyu; Zhang, Liming; Champion, C.

doi:10.1007/s00411-016-0681-2

Cited by 10 publications

(9 citation statements)

References 68 publications

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“…As already noted, recent work has questioned the premise that DEA is responsible for strand breakages in DNA. Notwithstanding this, we note here that values of DEA cross sections for all four DNA bases are found to be close to zero for electron energies below 1 eV . Hence, not much DEA is to be expected with thermal energy electrons.…”

Section: Discussionmentioning

confidence: 52%

“…Notwithstanding this, we note here that values of DEA cross sections for all four DNA bases are found to be close to zero for electron energies below 1 eV. 27 Hence, not much DEA is to be expected with thermal energy electrons. This is consistent with our observations that in the overwhelming majority of gel images that we accumulated in the course of our experiments, no signatures of SSB or DSB were seen in unirradiated samples.…”

Section: ■ Discussionmentioning

confidence: 59%

“…14 In the present experiments, our conditions (mainly the long laser pulse duration) ensure that both these plasma constituents have sufficient time to become thermalized. In the case of electrons, extensive computer simulations have been carried out 27 that have enabled yields to be deduced of various strand breaks and base damage via the DEA process. 3 As already noted, recent work 16 has questioned the premise that DEA is responsible for strand breakages in DNA.…”

Section: ■ Discussionmentioning

confidence: 99%

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Strong Strand Breaks in DNA Induced by Thermal Energy Particles and Their Electrostatic Inhibition by Na⁺ Nanostructures

Nayek¹,

Unnikrishnan

Salam

et al. 2019

J. Phys. Chem. A

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Low-power laser pulses of 6 ns duration (1064 nm wavelength) have been used to create plasma in an aqueous solution of plasmid DNA (pUC19). Thermal energy electrons and • OH radicals in the plasma induce strand breakages in DNA, including double strand breaks and possible base oxidation/base degradation. The time evolution of these modifications shows that it takes barely 30 s for damage to DNA to occur. Addition of physiologically relevant concentrations of a salt (NaCl) significantly inhibits such damage. We rationalize such inhibition using simple electrostatic considerations. The observation that DNA damage is induced by plasma-induced photolysis of water suggests implications beyond studies of DNA and opens new vistas for using simple nanosecond lasers to probe how ultralow energy radiation may affect living matter under physiological conditions.

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Section: Discussionmentioning

confidence: 52%

Section: ■ Discussionmentioning

confidence: 59%

Section: ■ Discussionmentioning

confidence: 99%

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Strong Strand Breaks in DNA Induced by Thermal Energy Particles and Their Electrostatic Inhibition by Na⁺ Nanostructures

Nayek¹,

Unnikrishnan

Salam

et al. 2019

J. Phys. Chem. A

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“…1 Notwithstanding recent questioning 15 of the premise that electron attachment is the precursor to strand breakages in DNA, we take cognizance of the fact that DEA cross sections for all four DNA bases are essentially zero for electrons possessing energies less than ∼1 eV. 24 Hence, we do not expect DEA to occur as a result of interactions involving thermal energy electrons. Moreover, in the overwhelming majority of gel images that we accumulated in the course of our measurements, we did not observe signatures of SSB or DSB in unirradiated, undoped plasmid DNA.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…In the case of low-energy electrons, extensive computer simulations have helped deduce the propensity for strand breaks and base damage via the dissociative electron attachment (DEA) process . Notwithstanding recent questioning of the premise that electron attachment is the precursor to strand breakages in DNA, we take cognizance of the fact that DEA cross sections for all four DNA bases are essentially zero for electrons possessing energies less than ∼1 eV . Hence, we do not expect DEA to occur as a result of interactions involving thermal energy electrons.…”

Section: Resultsmentioning

confidence: 99%

Thermal Energy Electrons and OH-Radicals Induce Strand Breaks in DNA in an Aqueous Environment: Some Salts Offer Protection Against Strand Breaks

et al. 2020

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Electrons and •OH-radicals have been generated by using low-energy laser pulses of 6 ns duration (1064 nm wavelength) to create plasma in a suspension of plasmid DNA (pUC19) in water. Upon thermalization, these particles induce single and double strand breakages in DNA along with possible base oxidation/base degradation. The time-evolution of the ensuing structural modifications has been measured; damage to DNA is seen to occur within 30 s of laser irradiation. The time-evolution is also measured upon addition of physiologically relevant concentrations of salts containing monovalent, divalent, or trivalent alkali ions. It is shown that some alkali ions can significantly inhibit strand breakages while some do not. The inhibition is due to electrostatic shielding of DNA, but significantly, the extent of such shielding is seen to depend on how each alkali ion binds to DNA. Results of experiments on strand breakages induced by thermalized particles produced upon plasma-induced photolysis of water, and their inhibition, suggest implications beyond studies of DNA; they open new vistas for utilizing simple nanosecond lasers to explore the effect of ultralow energy radiation on living matter under physiologically relevant conditions.

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Investigation on the correlation between energy deposition and clustered DNA damage induced by low-energy electrons

Liu

Tan

Zhang

et al. 2018

Radiat Environ Biophys

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This study presents the correlation between energy deposition and clustered DNA damage, based on a Monte Carlo simulation of the spectrum of direct DNA damage induced by low-energy electrons including the dissociative electron attachment. Clustered DNA damage is classified as simple and complex in terms of the combination of single-strand breaks (SSBs) or double-strand breaks (DSBs) and adjacent base damage (BD). The results show that the energy depositions associated with about 90% of total clustered DNA damage are below 150 eV. The simple clustered DNA damage, which is constituted of the combination of SSBs and adjacent BD, is dominant, accounting for 90% of all clustered DNA damage, and the spectra of the energy depositions correlating with them are similar for different primary energies. One type of simple clustered DNA damage is the combination of a SSB and 1-5 BD, which is denoted as SSB + BD. The average contribution of SSB + BD to total simple clustered DNA damage reaches up to about 84% for the considered primary energies. In all forms of SSB + BD, the SSB + BD including only one base damage is dominant (above 80%). In addition, for the considered primary energies, there is no obvious difference between the average energy depositions for a fixed complexity of SSB + BD determined by the number of base damage, but average energy depositions increase with the complexity of SSB + BD. In the complex clustered DNA damage constituted by the combination of DSBs and BD around them, a relatively simple type is a DSB combining adjacent BD, marked as DSB + BD, and it is of substantial contribution (on average up to about 82%). The spectrum of DSB + BD is given mainly by the DSB in combination with different numbers of base damage, from 1 to 5. For the considered primary energies, the DSB combined with only one base damage contributes about 83% of total DSB + BD, and the average energy deposition is about 106 eV. However, the energy deposition increases with the complexity of clustered DNA damage, and therefore, the clustered DNA damage with high complexity still needs to be considered in the study of radiation biological effects, in spite of their small contributions to all clustered DNA damage.

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Calculation on spectrum of direct DNA damage induced by low-energy electrons including dissociative electron attachment

Cited by 10 publications

References 68 publications

Strong Strand Breaks in DNA Induced by Thermal Energy Particles and Their Electrostatic Inhibition by Na⁺ Nanostructures

Strong Strand Breaks in DNA Induced by Thermal Energy Particles and Their Electrostatic Inhibition by Na⁺ Nanostructures

Thermal Energy Electrons and OH-Radicals Induce Strand Breaks in DNA in an Aqueous Environment: Some Salts Offer Protection Against Strand Breaks

Investigation on the correlation between energy deposition and clustered DNA damage induced by low-energy electrons

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Calculation on spectrum of direct DNA damage induced by low-energy electrons including dissociative electron attachment

Cited by 10 publications

References 68 publications

Strong Strand Breaks in DNA Induced by Thermal Energy Particles and Their Electrostatic Inhibition by Na+ Nanostructures

Strong Strand Breaks in DNA Induced by Thermal Energy Particles and Their Electrostatic Inhibition by Na+ Nanostructures

Thermal Energy Electrons and OH-Radicals Induce Strand Breaks in DNA in an Aqueous Environment: Some Salts Offer Protection Against Strand Breaks

Investigation on the correlation between energy deposition and clustered DNA damage induced by low-energy electrons

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Strong Strand Breaks in DNA Induced by Thermal Energy Particles and Their Electrostatic Inhibition by Na⁺ Nanostructures

Strong Strand Breaks in DNA Induced by Thermal Energy Particles and Their Electrostatic Inhibition by Na⁺ Nanostructures