FIGURE 5: Hypoxic treatment potentiates ER stress-induced impairment of the cysteine disulfide bond-formation in the ER of both wild-type and ρ^o mutant cells. At 30°C in YPD, wild-type BY4742 cells and the congenic ρ^o mutant carrying the pPM28 eroGFP-expression plasmid were aerobically grown, and were stressed by 0.5 mM DTT (or remained non-stressed (NS)) under the aerobic shaking or argon gas-filled condition for 30 min. The cells were then fluorescence-microscopically observed using two different excitation lights for measurement of the eroGFP values, the calculation method of which is described in the Materials and Methods section.