Conditions for mutagenesis in the cynanobacterium Aphanocapsa 6714

Conditions for induction of mutants have been studied in the unicellular, blue-green alga, Aphanosapsa 6714. Ethylmethanesulfonate, nitrosomethylurea, an acridine (euflavine) and γ-rays from 60Co induced no significant increase in mutant frequency although they produced classical killing effects. Methyl-nitro-nitrosoguanidine (NTG), at similar lethal doses, led to only a small increase in mutant yields. A useful mutagenic action was obtained only with ultraviolet light. This effect proved to be sensitive to photodependent repair processes, but not to dark excision repair systems. Attempts to adapt enrichment procedures by penicillin selective killing were unsuccessful.