Georgakilas, A.G., Haveles, K.S., Sophianopoulou, V., Sakelliou, L., Zarris, G. and Sideris, E.G. Alpha-Particle-Induced Changes in the Stability and Size of DNA.
The effect of α-particle radiation on the thermal stability and size of calf thymus DNA molecules in deoxygenated aqueous solutions was investigated by thermal transition spectrophotometry, pulsed-field gel electrophoresis, and standard agarose gel electrophoresis. The thermal transition of DNA from helix to coil was studied through analysis of the UV A260 absorbance. The results obtained for α particles of mean LET of 128 keV μm−1 reveal a dual dose response: a tendency for thermal stability of the DNA helix at “low” doses, followed by an increasing instability at higher doses. The same phenomenon was observed for the mean molecular weight of DNA molecules exposed to α particles. The results reported here for α particles in the low-dose region of 0–16 Gy are consistent with our previous hypothesis of inter- and intramolecular interactions of a covalent character in γ-irradiated DNA molecules in the dose region of 0–4 Gy.
