COMPARISON OF THE LETHAL EFFECTS OF DIFFERENT ACTINOMYCINS ON A REPAIR-DEFICIENT STRAIN OF ESCHERICHIA-COLI

We report here the isolation and purification of a genotoxic antibioti c from the culture medium of a Streptomyces strain. The antibiotic was identified as actinomycin X-2 by using a database search (AntiBase). In the previous studies a related compound, actinomycin D, has been sh own to be non-mutagenic in the salmonella/microsome assay and several other bacterial systems. The fact that an actinomycin was detected by a bacterial repair assay seems to contradict these results. Therefore we tested several actinomycins by differential killing assay based on the same Escherichia coli strains that were used in our screening bioa ssays. According to our results the uvrA, recA double mutant sensitize s E. coli to the genotoxic effects of actinomycins. (C) 1997 Elsevier Science B.V.