title: Changes in DNA flexibility after irradiation with gamma rays and neutrons studied with the perturbed angular correlation method.
abstract: Neutron and gamma irradiation of buffered solutions of calf thymus DNA resulted in changes in the dynamics of the macromolecule. In the low-dose region (0.8-10 cGy of 239Pu-Be neutrons and 0.34-3 Gy of 60Co gamma rays), the flexibility of DNA decreased as indicated by slower rotation of the molecules. Neutrons appeared to be approximately 35 times more effective than 60Co gamma rays. The rotational correlation time, tau C, was measured using the perturbed angular correlation (PAC) method. Its variation appears to follow a linear-exponential behavior. An attempt is made to formulate this behavior as a function of the energy deposited on the macromolecule (radiation dose), the average threshold energy (dose) required to form new lesions, and the available population of intact DNA sites.
authors.affiliation: NCSR Demokritos, Institute of Nuclear Physics, Athens, Grece.
authors.forename: E
authors.initials: E
authors.lastname: Tsoulou
authors.forename: C A
authors.initials: CA
authors.lastname: Kalfas
authors.forename: E G
authors.initials: EG
authors.lastname: Sideris
mesh_terms: D003037:Cobalt Radioisotopes; D004247:DNA / Q000737:chemistry* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D008962:Models, Theoretical; D009502:Neutrons; D009686:Nuclear Physics / Q000379:methods; D009690:Nucleic Acid Conformation / Q000528:radiation effects*
chemical_list: D003037:Cobalt Radioisotopes; D004247:DNA