Figure 1

PDR18 expression increases yeast tolerance to ethanol. Comparison of the susceptibility to ethanol-induced stress of S. cerevisiae parental strain BY4741 and the derived deletion mutant Δpdr18, through spot assays (A) or cultivation in liquid medium (B). Cells used for the ethanol susceptibility assays were mid-exponential phase cells (OD_600nm = 0.5±0.05) cultivated in minimal growth medium in the absence of stress. A: The susceptibility to inhibitory concentrations of ethanol of BY4741 and derived Δpdr18 strains, harboring a PDR18 expression plasmid or the corresponding cloning vector pRS416 was compared. The cell suspensions used to prepare the spots in lanes b) and c) were 1:5 and 1:25 serial dilutions, respectively, of the suspensions with an OD_600nm = 0.05±0.005 in lane a). B: Wild-type (▵, ▴) and Δpdr18 (□, ■) cell suspensions were also used to inoculate MM4 liquid medium in the absence (▵, □) or presence (▴, ■) of 6 % ethanol, with an initial OD_600nm = 0.05±0.005. Growth curves, followed by the measurement of the OD_600nm and the number of colony forming units (CFU) per ml, are representative of at least three independent experiments.