FIG 7 .

Pho4 is required for optimal growth of C. neoformans at physiological and alkaline pH. (A) The strains (100 μl; 1,000 cells/ml) were grown in standard tissue culture medium RPMI-FBS or murine serum as a stationary culture for 2 days at 37°C and 5% CO₂. Growth was measured by counting CFU. (B and C) Fungal cells were grown in shaking cultures at 30°C in RPMI-FBS buffered at pH 5.4 and 7.4 (B) or in MM containing 1 mM KH₂PO₄ with the pH adjusted to 6.8, 7.4, and 8 (C). Growth was initiated from a starting OD₆₀₀ of 0.05 and quantified 24 h later by measuring OD₆₀₀. Data shown are means ± SDs (three biological replicates). Statistical analysis was performed using t test. *, P < 0.05.