EXTENT OF DNA-DAMAGE IN DENSITY-SEPARATED TROUT ERYTHROCYTES ASSESSEDBY THE COMET ASSAY

The 'comet' assay is being increasingly employed for evaluating DNA da mage in biological systems. Using this technique. we examined DNA dama ge in whole and in density-separated trout erythrocytes. Results clear ly show that all the three considered parameters (tail length, tail in tensity and tail moment) increased with the density of the fractions, possibly reflecting different degrees of DNA damage. Probably, this be haviour is due to different periods of exposure of the density fractio ns to the hazard of active oxygen radicals; older cells have been expo sed to oxidative stress for a longer time. (C) 1998 Elsevier Science B .V.