DIAGNOSTIC COLOR DIFFERENTIATION PLATES FOR HEREDITARY RESPIRATION DEFICIENCY IN YEAST.

Nagai, Susumu (National Women's University, Nara, Japan). Diagnostic color differentiation plates for hereditary respiration deficiency in yeast. J. Bacteriol. 86:299-302. 1963.-Color differentiation between normal yeasts and their respiration-deficient mutants was improved by growing yeast colonies on nutrient agar plates containing several selected dyes and their mixtures. Magdala red (5 to 8 mg/liter) was good for single-color plates, giving deep-red sheen to the mutant colonies in contrast to the normal ones which tinted light red. A mixture of eosin (8 to 15 mg/liter, either Y or B) with trypan blue (15 to 20 mg/liter) was excellent in color and convenient to prepare, giving brilliant purple sheen to the mutant colonies contrasted to the normal ones which tinted grayish violet. These color plates were good over a broad range of Saccharomyces species, although the colony shades and suitable dye concentrations varied depending on the species and strains.