Influence of organic ions on DNA damage induced by 1 eV to 60 keV electrons
- Research Institute of Photocatalysis, Fuzhou University, Fuzhou 35002 (China)
- Groupe en sciences des radiations, Faculte de medicine, Universite de Sherbrooke, Sherbrooke, Quebec J1H 5N4 (Canada)
We report the results of a study on the influence of organic salts on the induction of single strand breaks (SSBs) and double strand breaks (DSBs) in DNA by electrons of 1 eV to 60 keV. Plasmid DNA films are prepared with two different concentrations of organic salts, by varying the amount of the TE buffer (Tris-HCl and EDTA) in the films with ratio of 1:1 and 6:1 Tris ions to DNA nucleotide. The films are bombarded with electrons of 1, 10, 100, and 60 000 eV under vacuum. The damage to the 3197 base-pair plasmid is analyzed ex vacuo by agarose gel electrophoresis. The highest yields are reached at 100 eV and the lowest ones at 60 keV. The ratios of SSB to DSB are surprisingly low at 10 eV ({approx}4.3) at both salt concentrations, and comparable to the ratios measured with 100 eV electrons. At all characteristic electron energies, the yields of SSB and DSB are found to be higher for the DNA having the lowest salt concentration. However, the organic salts are more efficient at protecting DNA against the damage induced by 1 and 10 eV electrons. DNA damage and protection by organic ions are discussed in terms of mechanisms operative at each electron energy. It is suggested that these ions create additional electric fields within the groove of DNA, which modify the resonance parameter of 1 and 10 eV electrons, namely, by reducing the electron capture cross-section of basic DNA units and the lifetime of corresponding transient anions. An interstrand electron transfer mechanism is proposed to explain the low ratios for the yields of SSB to those of DSB produced by 10 eV electrons.
- OSTI ID:
- 21559937
- Journal Information:
- Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 15 Vol. 133; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
60 APPLIED LIFE SCIENCES
AMINO ACIDS
ANIONS
BEAMS
BIOCHEMISTRY
CAPTURE
CARBOXYLIC ACIDS
CHARGE EXCHANGE
CHARGED PARTICLES
CHELATING AGENTS
CHEMISTRY
CHLORINE COMPOUNDS
COLLOIDS
CROSS SECTIONS
DAMAGE
DISPERSIONS
DNA
DNA DAMAGES
EDTA
ELECTRIC FIELDS
ELECTRON BEAMS
ELECTRON CAPTURE
ELECTRON TRANSFER
ELECTRONS
ELECTROPHORESIS
ELEMENTARY PARTICLES
FERMIONS
FILMS
GELS
HALOGEN COMPOUNDS
HYDROCHLORIC ACID
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INORGANIC COMPOUNDS
IONS
LEPTON BEAMS
LEPTONS
NUCLEIC ACIDS
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
PARTICLE BEAMS
SALTS
STRAND BREAKS
THIN FILMS
YIELDS