Comparison of luciferase activity of [ PSI+] and [ psi-] versions of the Ssa family. Overnight cultures were diluted in fresh SC medium lacking uracil to an OD600nm = 0.1. The cultures were then shifted to 37°C for 30 minutes to induce the expression of Hsp104. After 30 minutes at 37°C, the cultures were shifted to 45°C for 1 hour. Cyclohexamide was added to the cultures after 50 minutes at 45°C to prevent any further synthesis of luciferase during the recovery period. Luciferase activity, expressed as a percentage of pre-heat shock activity, was measured at regular intervals during the recovery period of 45 minutes at 25°C. White [PSI+], and black [psi-]. (Bar indicates SEM. Value followed by * are significantly different at p ≤ 0.05).