Strand Breaks in X-Irradiated Crystalline DNA: Alternating CG Oligomers

Abstract

Direct ionization of crystalline d(CGCGCGCG) and d(CGCGCGCGCG) oligomers produces 3'- and 5'-phosphate-terminated fragments as the main strand breakage products detectable by ion-exchange chromatography. The nature of the base has no effect on the probability of strand breakage at the given site. The yields of 3'-phosphates are systematically lower than the yields of the 5'-phosphates originating from the same cleavage site, pointing to the possible presence of unidentified products with sugar remnants attached to the 3'-end. These results show that direct ionization is efficient at producing single-strand breaks in DNA and its action is relatively indiscriminate with respect to base sequence.

Direct Damage to the Backbone of DNA Oligomers Is Influenced by the OH Moiety at Strand Ends, by the Type of Base, and by Context

“…Therefore, the magnitude of the end effect was influenced by which base was positioned at which end. Further, in general, the lability of the deoxyribose at the 3′ end appears to be greater than at the 5′ end, which is consistent with our earlier findings on base release7 and strand break products 12…”

Influence of two sterilisation ways, gamma-irradiation and heat treatment, on the volatiles of black pepper (Piper nigrum L.)

“…Hydroxyl radicals are very reactive and are known to interfere with the bonds between nucleic acids within a single strand, or between opposite strands. Although biological systems have a capacity to repair both single-stranded and double-stranded breaks of the DNA backbone, the damage occurring from ionising radiation is random and extensive (RazskazovskiY et al 2003). Therefore, the recovery processes in bacteria after their radiation damage are unlikely to occur.…”

Irradiation of spices - a review

“…Hydroxyl radicals are very reactive and are known to interfere with the bonds between nucleic acids within a single strand or between opposite strands. Although biological systems have a capacity to repair both single-stranded and doublestranded breaks of the DNA backbone, the damage occurring from ionising radiation is random and extensive (Razskazovskiy et al 2003). Therefore, recovery processes in bacteria after their radiation damage are unlikely to occur.…”