Studies of Euglena Mutants Resistant to U.V. and Nitroso Compounds

Abstract

<p> In order to compare the mode of action of mutagens which cause mass conversion of green Euglena to colorless forms lacking chloroplasts, mutants were selected either for resistance to U.V. light or for resistance to N-methyl-N-nitroso-p-toluenesulfonamide (MNTS). The U.V. resistant mutants selected showed strong resistance to U.V. but the slow growth of these mutants indicated that they probably carried multiple lesions. Some of the problems inherent in selection techniques were explored and discussed. A mutant selected for resistance to MNTS was found to have the ability to convert MNTS to an innocuous compound N-methyl-p-toluenesulfonamide. Experiments using the MNTS resistant strain provide information concerning the mode of action of MNTS and the related mutagen nitrosoguanidine.</p>