title: Action spectrum for the induction of single-strand breaks in DNA in buffered aqueous solution in the wavelength range from 150 to 272 nm: dual mechanism.
abstract: The induction of single-strand breaks by vacuum-u.v. and far-u.v. radiations (150 nm-272 nm) in plasmid Col E1 DNA in buffered aqueous solution was studied by agarose gel electrophoresis. The results indicated that the mechanisms of DNA strand-break induction are different in the two u.v. regions: above 210 nm the direct excitation of DNA seemed to be the main cause; below 180 nm the photolysis of solvent water seemed to be essential. The demonstration of a systematic protection at 160 nm and not at 209 nm by OH scavengers, such as ethyl alcohol, potassium iodide and D-mannitol, supports the involvement of OH radicals in the vacuum-u.v. region.
mesh_terms: D002021:Buffers; D002847:Chromatography, Agarose; D004247:DNA / Q000528:radiation effects*; D004249:DNA Damage; D006878:Hydroxides; D010957:Plasmids; D012996:Solutions; D014466:Ultraviolet Rays; D014867:Water
chemical_list: D002021:Buffers; D006878:Hydroxides; D012996:Solutions; D014867:Water; D004247:DNA