Fig. 3.

HSF1A does not inhibit C. botulinum C2-mediated intoxication of HeLa cells. (A) HeLa cells were pretreated with 50 µM HSF1A or with 50 µM of the HSP90 inhibitor radicicol (Rad) for 1 h at 37 °C before intoxication. DMSO served as control. The cells were intoxicated with TcdB (5 pM) or C2 toxin (50 ng/mL C2I plus 100 ng/mL C2IIa). Pictures were taken after 100 min. (Scale bar: 100 µm.) (Insets) Magnifications of dotted areas. (B) The percentage of rounded cells per picture (>200 cells) is given as mean ± SD (n = 8). Student’s t test was applied for statistical comparison. ***P < 0.001; n.s., not significant (P > 0.05). (C) Autoradiograph and Western blot analysis of lysates of C2 toxin-intoxicated cells, treated with additional C2I (40 nM) and radiolabeled [³²P]NAD (1 mM) after 100 min of intoxication. (D) Quantification of the autoradiograph shown in C. Values are average ± SD (n = 3). Student’s t test was applied for statistical comparison. **P < 0.01; n.s., not significant (P > 0.05).