FIG 1.

Calcineurin is required for hyphal growth in C. tropicalis. (A) Hyphal growth of C. tropicalis wild-type (WT) and mutant strains on filament-inducing agar plates. Cells were grown overnight, washed twice with dH₂O, and serially diluted to 10³ cells/ml (based on an OD₆₀₀ of 1 being equal to ∼4 × 10⁷ cells/ml). One hundred microliters containing ∼100 cells was spread on a variety of filament-inducing media and incubated at 37°C for the number of days indicated. The experiments were repeated at least three times, and one representative image is shown. Bar = 0.1 mm. (B) Hyphal growth of C. tropicalis wild-type and mutant strains in liquid bovine calf serum (100%). Cell preparations were as described above with minor modifications. Two microliters of cells at an OD₆₀₀ of 1/ml were added to microtiter wells prefilled with 98 μl of 100% bovine calf serum, resulting in an OD₆₀₀ of 0.00004 (∼1.6 × 10³ cells) in each well. Cultures in the 96-well polystyrene plates were incubated at 37°C without shaking for 24 h. Bar = 40 μm.