and B, total RNA was isolated from six different strains that were either maintained at constitutive conditions (30 °C) or heat shocked at 37 °C for 15 min. A representative Northern blot is shown for the transcripts HSP104, HSP12, HSP26, and ACT1 (loading control). The bar graph below illustrates heat induction, which was calculated as the -fold change of the normalized transcript between heat shock conditions versus constitutive conditions. The asterisks indicate significant differences between wild-type and the condition tested using Student’s t test: **, p < 0.01; ***, p < 0.001.