Yeast Viability and Vitality Assays for Flow Cytometry
Optimized for use in yeast cells, our FungaLight series of yeast viability and vitality assays for flow cytometry allow clear separation of living and dead cells based on various cellular characteristics. Due to the inherent differences between prokaryotic and eukaryotic cells, specialized dyes must be used to differentiate live and dead cell populations in yeast.
Membrane Integrity Yeast Viability Kit
The LIVE/DEAD FungaLight Yeast Viability Kit for flow cytometry enables researchers to easily, reliably and quantitatively distinguish live and dead yeast in minutes. The kit contains solutions of the SYTO 9 green-fluorescent nucleic acid stain and the red-fluorescent nucleic acid stain, propidium iodide. These stains differ both in their spectral characteristics and in their ability to penetrate healthy yeast cells.
When used alone, the SYTO 9 stain generally labels all yeast in a population—those with intact membranes and those with damaged membranes. In contrast, propidium iodide penetrates only yeast with damaged membranes, causing a reduction in the SYTO 9 stain fluorescence by fluorescence resonance energy transfer (FRET) when both dyes are present. As a result, yeast with intact membranes stain fluorescent green, whereas yeast with damaged membranes stain fluorescent red.
Figure 1. Saccharomyces spp. cell suspensions stained with the LIVE/DEAD FungaLight Yeast Viability Kit. Panel A shows the dot plot of forward scatter vs. side scatter of an untreated Saccharomyces culture, washed and stained with SYTO 9 dye and propidium iodide as described in the protocol. The region R1 contains particles of the appropriate size for yeast cells; the forward scatter trigger is set to exclude debris in the sample. Panel B shows the R1-gated staining pattern obtained following analysis of a sample of yeast containing a mixture of both live and heat-killed cells.
Metabolic Activity Yeast Viability Kit
The FungaLight Yeast CFDA, AM/Propidium Iodide Vitality Kit combines a cell permeable esterase substrate with a membrane integrity indicator to evaluate the vitality of yeast cells by flow cytometry or microscopy. The kit contains the cell permeant esterase substrate 5-carboxyfluorescein diacetate (CFDA) and the cell impermeant nucleic acid stain, propidium iodide. With an appropriate mixture of the CFDA, AM and propidium iodide stains, esterase-active yeast with intact cell membranes stain fluorescent green, whereas yeast with damaged membranes stain fluorescent red.
Figure 2. FungaLight CFDA AM/Propidium Iodide Flow Cytometry Yeast Vitality Kit. Saccharomyces spp. cell suspensions stained with CFDA AM dye and propidium iodide and analyzed using a flow cytometer. The dot plot shows the staining pattern obtained following analysis of a yeast sample containing a mixture of both live and alcohol-killed cells. The sample was gated on the yeast population by scatter, and appropriate compensation was applied. Vital cell events are distinguished from nonvital events by both esterase activity and membrane integrity.
For Research Use Only. Not for use in diagnostic procedures.