Alpha-Particle-Induced Changes in the Stability and Size of DNA

Abstract

The effect of alpha-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 A(260) absorbance. The results obtained for alpha particles of mean LET of 128 keV microm(-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 alpha particles. The results reported here for alpha 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 gamma-irradiated DNA molecules in the dose region of 0-4 Gy.

Induction and Processing of Oxidative Clustered DNA Lesions in56Fe-Ion-Irradiated Human Monocytes

“…In addition, several in vitro studies using different DNAs in radio-quenching solutions indicate a similar decrease of clusters with increasing LET (43,(51)(52)(53). This decrease could be the result of an actual decline in the induced oxybase lesions (54) and SSBs (43,55) for high-LET charged particles or an inability of the method to detect these highly dense clusters. By the last comment, we refer to the already established compromised ability of repair enzymes to detect and cleave very closely spaced DNA lesions (14,31,56).…”

Alpha Particles Induce Apoptosis through the Sphingomyelin Pathway

“…Roger Howell and Edouard Azzam (UMDNJ, Newark, NJ), who initially modified the Metting version (27). Although analogous α-particle irradiation devices have been described (28, 29), they did not offer some of the practical features for aseptic cell culture work (separate autoclavable dishes with thin-film windows) and uniformity of irradiation (planar thin-film exit window, rotating source, orbital collimator) that the device by Howell and Azzam featured.…”

DNA excision repair and double-strand break repair gene polymorphisms and the level of chromosome aberration in children with long-term exposure to radon

“…Low-and high-LET radiation cause same number of individual DNA lesions per unit of absorbed dose but in a case of high-LET (a-particles) these lesions are distributed within a smaller number of sites (segments of DNA), which implies a higher level of cluster complexity, i.e. the average number of lesions per cluster tends to increase with increasing LET (Georgakilas et al 2000(Georgakilas et al , 2013.…”