DEVELOPMENT OF A METHOD BASED ON ALKALINE GEL-ELECTROPHORESIS FOR ESTIMATION OF OXIDATIVE DAMAGE TO DNA IN ESCHERICHIA-COLI

A method for estimating DNA strand breakage and subsequent repair base d on alkaline gel electrophoresis was developed and tested with isogen ic strains of Escherichia coli deficient in DNA repair enzymes, Sample s from a cell suspension were removed at 2 min intervals following a 1 5 min exposure to 20 mmol l(-1) H2O2. Catalase was added and the cells were embedded in blocks of low-melting point agarose and lysed, After alkaline gel electrophoresis, photographs of the gels were taken and the relative lengths of the distributions of DNA fragments were measur ed with a scanner and computer, The lengths were correlated with survi val of the cells exposed to H2O2 and with the importance of particular DNA repair enzymes, Alkaline gel electrophoresis appears to be a rela tively simple method for analysing the level of H2O2-caused DNA damage and repair in E. coli.