Mutagenic action of methyl methane sulphonate on the bluegreen alga Anacystis nidulans

Abstract

Growth of the blue-green alga Anacystis nidulans treated with methyl methane sulphonate (MMS) at pH 5 or 6 was better than that at pH 7 or 8, both in regard to the duration of the lag-phase and the growth rate. Toxicity of MMS was directly proportional to the temperature at which the cells had been treated. Growth of cells incubated at 5000 lux during MMS treatment was better than those that had been treated in the dark or at 15000 lux. Ten successive treatments with MMS were ineffective in significantly shortening the lagphase of treated cells. The frequency of ultraviolet-resistant mutants but not of streptomycin-resistant mutants was substantially increased following single treatment with MMS of 40-60 minute duration; treatments of longer duration resulted in a steep fall in the number of mutants suggesting thereby that treatments of up to 60 min induce genetic changes which are largely unaccompanied by physiological damage.