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Figure 3 | Microbial Cell Factories

Figure 3

From: Increased expression of the yeast multidrug resistance ABC transporter Pdr18 leads to increased ethanol tolerance and ethanol production in high gravity alcoholic fermentation

Figure 3

PDR18 over-expression increases ethanol tolerance and protects from ethanol-induced plasma membrane permeabilization. A: Comparison of the susceptibility to ethanol induced stress of S. cerevisiae parental strain BY4741 and the derived deletion mutant BY4741_Δpdr18, and PDR18 over-expression strain BY4741_ + PDR18 through spot assays. Cells used for the spot assays were mid-exponential phase cells (OD600nm = 0.5±0.05) cultivated in minimal growth medium in the absence of stress. 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 OD600nm = 0.05±0.005 in lane a). B: Comparison of the membrane permeability exhibited by S. cerevisiae yeast strains BY4741, BY4741_Δpdr18 and BY4741_ + PDR18, grown to mid-exponential phase and exposed (white columns) or not (grey columns) for 30’ to mild-stress induced by 4 % ethanol. Cell permeability was assessed based on the fluorescence intensity exhibited by yeast cells upon passive accumulation of propidium iodide. Fluorescence intensity values are the means of at least three independent experiments, error bars indicating standard deviation.

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Microbial Cell Factories

ISSN: 1475-2859

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