Bacterial Viability

Bacterial Viability via Flow Cytometry

Using flow cytometry an investigator can determine what percentage of a prokaryotic population is alive and what percentage is dead. You can also distinguish other forms of viability via flow cytometry using a myriad of different viability stains. These can be seen with the corresponding paper under additional information on the bottom of the page. For the live/dead protocol the population is stained with two dyes, Syto-9 and PI. Syto-9 stains the DNA of cells indiscriminately, while PI stains only the cells with a compromised membrane. With the two stains combined, only live cells are stained with syto-9, with only compromised (dead) cells staining with PI.

For this example a 50/50 mix of live and dead cells were combined. The cells were stained with the Baclight kit and then run on the BD FACSCanto Flow Cytometer. Along the X-Axis is the Syto-9(FITC) parameter and the Y-Axis is PI(PE) parameter. We can see from the results how close the flow cytometer was at getting the correct reading. Below is another example using a 20% live/80% dead mixture.

From these examples we can see the utility of using flow cytometry to study bacterial viability. Please see the following for more information.

Additional Information:

• Bacterial Viability Paper

• Molecular Probes Baclight Cell Death kit