AAT Bioquest

Live or Dead™ Yeast Viability Assay Kit


Molecular weight
The Live or Dead™ Yeast Viability Assay Kit is a reliable and robust assay that allows researchers to quantitatively distinguish live and dead yeast within minutes using flow cytometry. This kit contains two ready-to-use nucleic acid stains: MycoLight™ Green JJ98, a replacement for SYTO™ 9, and propidium iodide. MycoLight™ Green JJ98 is a green fluorescent nucleic acid stain that labels all yeast populations - live yeast with intact membranes and dead yeast with damaged membranes. In contrast, propidium iodide only stains dead yeast with damaged membranes. In dead yeasts where both dyes are present, the fluorescence of MycoLight™ Green JJ98 is notably reduced due to FRET by propidium iodide. As a result, live yeast with intact membranes will stain fluorescent green, and dead yeast with damaged membranes will stain fluorescent red.


Example protocol


Protocol Summary
  1. Prepare yeast samples
  2. Add 1 µL MycoLight™ Green JJ98 dye
  3. Add 2 µL propidium iodide dye
  4. Gently vortex, and incubate at 37°C for 15-30 minutes
  5. Analyze with flow cytometer using 530/30 nm and 576/26 nm filters 

Allow the components to warm to room temperature before opening the vials. Propidium iodide binds to nucleic acids, it should be treated as a potential mutagen and handled with appropriate care. The DMSO stock solution should be handled with particular caution as DMSO is known to facilitate the entry of organic molecules into tissues.


The following protocol should be used only as a guideline.
  1. Prepare yeast samples containing 1 mL of suspension at ~106 cells/mL.
  2. Add 1 µL of MycoLight™ Green JJ98 (Component A) and 2 µL of propidium iodide (Component B) to each tube of experimental samples. For unstained controls, place 1 set of tubes aside without adding dye. For single color MycoLight™ Green JJ98 controls, add 1 µL of MycoLight™ Green JJ98 to one tube of untreated cells and to one tube of killed cells. For single color propidium iodide controls, add 1 µL of propidium iodide to one tube of untreated cells and to one tube of killed cells. Please note, depending upon your specific application the proportion of the two dyes may need to be adjusted for optimal response.
  3. Vortex each tube gently. Then incubate all samples at room temperature for 15 to 30 minutes, protected from light.
  4. Monitor the fluorescence increase using a flow cytometer equipped with a 488 nm laser, and a 530/30 nm filter and a 575/26 nm filter (FITC and PE channel).
    Note     To analyze the samples with fluorescence microscopy, trap 5 µL of the stained yeast suspension between a slide and a coverslip. Observe in a microscope using FITC and Cy3 filter set.


Common stock solution preparation

Table 1. Volume of DMSO needed to reconstitute specific mass of Live or Dead™ Yeast Viability Assay Kit to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

0.1 mg0.5 mg1 mg5 mg10 mg
1 mM187.266 µL936.33 µL1.873 mL9.363 mL18.727 mL
5 mM37.453 µL187.266 µL374.532 µL1.873 mL3.745 mL
10 mM18.727 µL93.633 µL187.266 µL936.33 µL1.873 mL

Molarity calculator

Enter any two values (mass, volume, concentration) to calculate the third.

Mass (Calculate)Molecular weightVolume (Calculate)Concentration (Calculate)Moles

Product Family