Figure 4.
Impact of pH and temperature on K66 toxin functionality. (A) Sensitive S. cerevisiae strain a’1 was seeded into MBA medium (2 × 106 cells/plate, adjusted to pH values between 3.2 and 6) and 100 µL of the concentrated K66 toxin poured into 10 mm wide wells, cut in the agar layer. Plates were incubated for 2 days at 25 °C, non-growth zones around the wells measured and expressed as mean of three independent experiments in percent ± SD. (B) Sensitive yeast a’1 cells (5 × 105 cells) were mixed with 500 µL of 100-fold concentrated K66 toxin or the same volume of heat-inactivated K66 toxin and incubated for 24 h at different temperatures. Yeast cells were then serially diluted and spotted onto YPD-agar plates following for 2 days incubation at 25 °C.