Fig. 3. Hemolytic activity and inhibition with sphingomyelin of recombinant Eqts. The amount of
bacterial supernatant that corresponds to t50=3 min was incubated with sphingomyelin at 33 mg/ml for
2 min and afterwards hemolytic activity was determined as described (Anderluh et al., 1996) on 2 ml of
bovine red blood cells at 258C. The activity of toxins preincubated with sphingomyelin (hatched) was
compared to that of toxins preincubated with water (open) as controls. Plasmids pAG2.1, pAG2.2 and
pAG2.3 code for recombinant Eqts II, IV and V, respectively. The supernatant of bacteria with pT7±7
alone was not hemolytic. Means+S.D. of two measurements are shown.