In my project I am measuring the survival rate of the yeast cells after in-vitro exposure to gastrointestinal conditions.
Previously a masters student used Plate Counting to determine the survivability of the strains and observed 4 % of the survivability.
Later I run the same protocol in another date and used Flow Cytometer to determine the survivability. I did not use a stain for the live cells, but only used propidium iodide for the dead cells. Positive and negative controls showed the clear difference between the cells from the fresh culture vs cells exposed to 70% isopropanol for 1h.
In my experiment, 99% of the cells were in the "alive" zone.
I am trying to find resources to understand why there is such a big difference in these two methods. Could it be VBNC, something regarding the stains or something else?
Hi!
1) Try to check your protocol by calculate CFU on the solid media (Saburo for Candida); 2) to minimize time between preparation inoculum and starting the procedure cells calculation (this is important for escape inoculum effect); 3) try to use more QC on every steps.
BW
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