Figure 2. RNAi suppression of heat shock-induced up-regulation of PaHsp70 expression and its effect on survival.

Relative levels of Pahsp70 mRNA (A), PaHsp70 protein (B) and Pahsc70 mRNA (C) were measured in the fat bodies of male Pyrrhocoris apterus at different times of recovery after the heat shock (+41°C for 1 h). The insects were either untreated (control) or injected two days prior to heat shock with: 2 µL of the injection buffer alone (blank); 2 µL (10 µg) of ß-galactosidase (ß-gal) dsRNA; or 2 µL (2 µg) of Pahsp70 dsRNA. Each column is a mean±S.E.M. of 3–4 independent samples (5 fat bodies per sample). The differences in mRNA levels were assessed by ANOVA followed by Tukey's multiple comparison test at p = 0.05 (columns flanked by different letters differ significantly). (D) An example of Western blotting. (E, F) Survival in blank-injected (E, n = 39) and Pahsp70 dsRNA-injected (F, n = 40) insects after a severe heat shock (+45°C for 3 h) were assessed during recovery at 25°C for 7 days. The fit insects were those showing normal, rapid and coordinated crawling; the injured insects displayed signs of heat injury, i.e. slow, uncoordinated crawling or movements of body appendages only; and the dead insect did not respond to stimulation with a fine paintbrush. See Fig. 1 for more information.