DNA radiolysis by fast neutrons
M Spotheim-Maurizot1, M Charlier, R Sabattier
1Centre de Biophysique Moléculaire, CNRS, Orléans, France.
International Journal of Radiation Biology
|February 1, 1990
Summary
Fast neutron irradiation causes fewer DNA single-strand breaks but more double-strand breaks than gamma rays. Ethanol scavenging suggests multiple origins for neutron-induced DNA damage.
Area of Science:
- Molecular Biology
- Radiation Biology
- Biophysics
Background:
- Understanding DNA damage mechanisms is crucial for radiation protection and therapy.
- Fast neutrons and gamma rays induce DNA damage through different physical and chemical processes.
Purpose of the Study:
- To compare the DNA damage yields induced by fast neutron and gamma irradiation.
- To elucidate the mechanisms underlying neutron-induced DNA double-strand breaks.
Main Methods:
- Irradiation of pBR322 plasmid DNA in solution with fast neutrons and 60Co gamma rays.
- Analysis of single-strand breaks (ssb) and double-strand breaks (dsb) yields.
- Investigation of the role of hydroxyl (OH.) radicals using ethanol as a scavenger.
Main Results:
- Neutrons produced half the ssb yield and 1.5 times the dsb yield compared to gamma rays.
- Ethanol inhibited all neutron-induced ssb but only 85% of dsb, while completely inhibiting gamma-induced ssb and dsb.
- Results suggest three origins for neutron-induced dsb: radical transfer, high-density track radical attack, and direct neutron effects.
Conclusions:
- Neutron and gamma irradiation induce DNA breaks via distinct mechanisms.
- A significant portion of neutron-induced dsb results from OH.-mediated processes, while direct physical effects also contribute.
- These findings offer insights into the radiobiology of fast neutrons.
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