FIG. 7.
Sulfa drug resistance assay in liquid medium of the recombinant S. cerevisiae strains with mutated or wild-type FOL1. Cells at 2.5 × 106/ml were incubated in minimal medium lacking PABA or containing 0.05 μg of PABA/ml (+ pABA) with increasing concentrations of sulfa drugs for 3 to 4 days at 30°C, and the absorbance at 540 nm was measured. Circles, strain WT; squares, strain M1; triangles, strain M2; ×, strain M3. One representative experiment out of three is shown. The error bars indicate standard deviations of duplicate measurements.