Figure 7. Compound 1 but not 3 inhibits intoxication of Vero cells with Clostridium (C.) perfringens iota toxin.

(a) Influence of 1 on intoxication of Vero cells with C. perfringens iota toxin. Vero cells were pre-incubated for 30 min at 37 °C with 100 μM 1 and for control with 10 μM radicicol (Rad) or left untreated for control. Subsequently, iota toxin (50 ng ml⁻¹ Ia plus 100 ng ml⁻¹ Ib) was added and cells were further incubated at 37 °C. Pictures show the morphological changes after 2 h of toxin treatment. For quantitative analysis, percentage of rounded cells was determined from the pictures taken at the indicated time points. Values are given as mean ± SD (n = 3). (b) The inactive analog 3 of the Hsp70 inhibitor 1 has no effect on intoxication of Vero cells with iota toxin. Vero cells were pre-incubated for 30 min at 37 °C with 100 μM 1, 100 μM 3 or 200 μM 3 or left untreated (control). Subsequently, iota toxin (50 ng ml⁻¹ Ia plus 100 ng ml⁻¹ Ib) was added and cells were further incubated at 37 °C. Pictures show the morphological changes after 4 h of toxin treatment. For quantitative analysis, percentage of rounded cells was determined from the pictures taken at the indicated time points. Values are given as mean ± SD (n = 3).