The yeast cells were grown in YPD (1% yeast extract, 2% peptone and 2% dextrose), YPGAL (1% yeast extract, 2% peptone and 2% galactose) or complete synthetic medium (0.17% yeast
nitrogen base (YNB), 0.5% ammonium sulfate, all required amino acids plus 2% glucose). SD = synthetic dextrose medium. For most analyses, when yeast strains were grown on glucose or galactose, the cells were harvested by centrifugation at stationary phase, which corresponds to an OD600 nm between 2.0 and 5.0. Viability assays: The tolerance of yeast cells to H2O2 or to t-BOOH was determined by the spot test, Bafilomycin A1 as described below. Inoculates were obtained from cells that were grown overnight in YPD or complete synthetic media with 2%
glucose (indicated in the figures). Combretastatin A4 Inoculates were diluted to OD600 nm = 0.2, and yeasts were grown until cell density reached stationary phase (around 16 h). Finally, the cell cultures were diluted again to OD600 nm = 0.2, and then four subsequent 1:5 dilutions of these cell suspensions were performed. A 5 μL droplet of each dilution was plated onto YPD or complete synthetic medium (SD) plus agar with the stress agent. Peroxides were added to plates at the concentrations indicated in the figures. DTT or tunicamycin was spread onto the plates just before use. To test cell viability under 4-Aminobutyrate aminotransferase heat shock conditions, the strains were grown until cell density reached OD600 nm = 0.8, and they were divided into two aliquots, which were incubated at 30°C (control) or 37°C. The serial dilutions (starting from OD600 nm = 0.2) were spotted onto YPD agar plates, and the plates were incubated for 48 h at 30°C. Construction of yeast overexpression vector pYES-TOPO + POF1: The coding region of POF1 gene was cloned from
yeast genomic DNA using the following specific MRT67307 primers: POF1 forward 5′TGCTGTCACATATGAAGAAGAC and POF1 reverse 5′TAAACGGATCCTCAATCAAATATTG, which contain NdeI or BamHI restriction enzyme sites adaptors, respectively (underlined sequences). This PCR-isolated DNA fragment was purified with the GFX PCR DNA and Gel Band Purification kit (GE Healthcare, Uppsala, Sweden) and ligated into the pYES-TOPO backbone to form pYES-TOPO + POF1 for yeast expression (controlled by GAL1 promoter) and into the pET15b vector to generate pET15b + POF1 for bacterial expression (controlled by T7 promoter). The POF1 gene was added to pYES2.1-TOPO TA (Invitrogen) reaction media according to the manufacturer. The ligation product was transformed into Escherichia coli DH5α bacteria strain by electroporation. The transformed clones were grown in LB + ampicillin (100 μg/mL), and the plasmids were isolated with the Illustra plasmidPrep Mini Spin Kit (GE Healthcare).