FIGURE 6: Oxygen consumption of wild-type and ρ⁰ yeast cells under non-stress and ER stress conditions. After being aerobically shaken at 30°C, YPD cultures of wild-type BY4742 cells and those of the congenic ρ^o mutant were subjected to measurement of the oxygen-consumption rate in the presence or absence of 0.5 mM DTT. The oxygen uptake ratios were the calculated as described in the Materials and Methods sections, and are normalized against that of non-stressed wild-type cells, which is set at 1.0. *: p < 0.05, **: p < 0.01.