FIG. 3.

Effect of staining with PI alone (A) and PI and FDA simultaneously (B) after exposure of A. polyphaga cysts to PHMB for 4 h. Of 10,000 treated cells, 50% appeared viable after staining with PI alone (A [lower quadrant]) and 80% appeared viable after staining with PI and FDA (B [upper right quadrant]). The analysis gates (from amoebae stained with PI and FDA) were set with fluorescence from control live (FL1-H, ≥400; FL2-H, ≥520) and heat-killed (FL1-H, <400; FL2-H, ≥520) cells. Analysis gates for cells stained with PI were set as previously described.