Production of respiration-deficient mutants of yeast by some quinone-imine dyes

Basic quinone-imine dyes were tested for their effect in producing respiration-deficient mutants of baker's yeast. Some dyes of a subclass, azine dyes (Table I) were found to be effective, but neutral red was ineffective. Janus green B, which is ordinarily classified as an azo dye, was also tested and found to be strongly effective. Oxazine and thiazine dyes so far tested (Table II) were ineffective except one. This exception was Nile blue, an oxazine dye, of which a preparation from Grübler was strongly effective, while those from Tokyo Kasei and Merck were only weakly effective.The dyes were examined by paper chromatography. Development with acetone-water (4:6) and tert.-butanol-acetic acid-water (4:1:5) gave fairly good results. A few dyes were satisfactorily pure, but many others separated into two or more components.Efficacy of the dyes to produce the respiration-deficient mutants in relation to the chemical properties was discussed.