The comet assay detects adaptation to MNU-induced DNA damage in barley

We have established the comet assay for detection of DNA damage in barley. Immediately after treatment with the monofunctional alkylating agent MNU, a dose-dependent increase of DNA damage (mainly DNA breaks) was detected by the alkaline denaturation/neutral gel electrophoresis (A/N) variant of the comet assay in nuclei isolated from root tip meristems and from young leave s. A reduction of damage was observed within meristematic nuclei but not in differentiated leaf nuclei 48 h after treatment. Adaptive pretreatment wit h a nontoxic dose of cadmium chloride prior to challenge treatment with MNU reduced the frequency of chromatid type aberrations, micronuclei and aneup loid cells as well as the amount of DNA in comet tails of meristematic nucl ei. (C) 2001 Elsevier Science B.V. All rights reserved.