Induction of petite mutation with acriflavine and elevated temperature in Candida albicans

A method of inducing respiratory deficient (petite) mutation in Candida albicans (which has been previously classed as a petite-negative yeast) and characteristics of some isolated mutants are reported. When grown at 42 degrees C in the presence of a cytoplasmic mutagen (acriflavine), C. albicans exhibited diauxie-like biphasic growth. Mutants which were unable to grow on a non-fermentable substrate, glycerol, were isolated from the above culture at a frequency of less than 1%. The simultaneous action of both acriflavine and a supraoptimal temperature of 42 degrees C was required to induce respiratory mutation. The respiratory mutants were separated into two groups: i. mutants exhibiting a complete cytochrome spectrum but with low respiratory activity and ii. those deficient in cytochrome aa3. Further characterization of their respiratory activity, colony morphology, mitochondrial morphology and growth manner supported the evidence that members of the latter group can be regarded as petite mutants.