Switching frequencies of white-gray-opaque transitions in C. dubliniensis (PC35) under different culture conditions. Wh, white; Gr, gray; Op, opaque. Colonies (strain PC35) were grown under the indicated conditions at 25°C for 6 d. YPD, Lee's glucose, and Lee's GlcNAc media were used. Switching frequency = average ± standard deviation (SD). (A) Switching frequencies in air. (B) Switching frequencies in 5% CO2. (C) Switching frequencies in 20% CO2.