<i>In vivo</i> staining of the mitochondrion to measure the membrane potential by Rhodamine 123 dyes.

<p>2×10⁶ cells in 1 ml supernatant were incubated with Rhodamine 123 (5 µg/ml) for 20 min at 30°C. Cell pellets were resuspended in 20 µl PBS and visualized with Carl Zeiss 710 LSM microscopy. The relative fluorescence signal of each strain is shown in the right panel.