Can FUN 1 stained cells be examined by flow cytometry?
Yes. Use a 488 nm laser line and standard FITC and PE channels for two-color detection of green (dead/metabolically inactive cells) and red (live, metabolically active cells) emission.
Live, metabolically active fungi transport FUN 1 into vacuoles to give a red-shifted fluorescence versus green/yellow fluorescence in the nucleus and cytoplasm of dead or metabolically-inactive cells. Is this a reliable indicator of fungal viability?
No. FUN 1 accumulates into vacuoles by an unknown transport pathway, but any mutants/ recombinant cells or experimental treatments that result in a deficiency or block in vesicle-mediate transport into vacuoles may result in cells that do not have red vacuoles, even though the cells are live and metabolically active. For more information see J Microbiol Methods 78:208 (2009).