Detection of 8-hydroxy-2-deoxyguanosine as a marker of oxidative damage in DNA and germplasm exposed to cryogenic treatments.

An HPLC method has been optimised to measure 8-hydroxy-2-deoxyguanosine (8OHdG) in DNA and germplasm with the objective of using the adduct as a marker of cryostorage stability. The encapsulation-dehydration cryopreservation protocol was adapted as a model system for assessing the formation of 8OHdG from alginate-encapsulated DNA of calf thymus (CT) and currant species (Ribes) exposed to temperatures of -20 and -196 degree C. The presence of H2O2 exacerbated the formation of 8OHdG in encapsulated CT and Ribes DNA. Production of the oxidized adduct was lower in the plant system. A reduction in residual water following osmotic dehydration and evaporative desiccation was associated with reduced adduct formation in encapsulated DNA. No significant differences in 8OHdG adduct formation were observed in plants regenerated from cryopreserved Ribes meristems derived from genotypes known to have differential tolerance to cryopreservation.