FIG. 7.

ClpB is required for induced thermotolerance. Cultures of wild-type L028 and ΔclpB mutant strains were grown exponentially until the OD₆₀₀ reached 0.3. Half of the culture was preincubated for 20 min at the nonlethal temperature of 48°C, while the other half was maintained at 37°C. After preincubation, both cultures were incubated at 60°C, and cell survival was evaluated by plating diluted aliquots. White bars indicate CFU values before incubation at 60°C; black bars indicate CFU values after 5 min of stress.