FIG 9 .

Effect of purified Stx2 on Tetrahymena protein synthesis. Tetrahymena cells (5 × 10⁴/ml) were separately incubated with 200 ng/ml Stx2, 200 ng/ml BSA, or 0.5 mM paromomycin for 60 min and subsequently assayed for protein synthesis as described in Materials and Methods. [³⁵S]methionine incorporation into protein was determined by scintillation counting and is represented as counts per minute per Tetrahymena cell. Error bars represent standard deviations from three or more independent experiments, with each experiment comprising a minimum of three individual measurements. *, P < 0.001.