Fig. 2

Cell growth of the wild and ∆degP mutant strains in YS medium. The strains were incubated at 55 °C (wild strain, ; ∆degP strain, ) or 60 °C (wild strain, ; ∆degP strain, ) in YS medium after preincubation at various temperatures. Preincubation was carried out at 55 °C for the wild strain. As for the ∆degP mutant strain, when its cell growth was measured, it was preincubated at 55 °C; when measured at 60 °C, it was preincubated at 57 °C for 15 h and then at 60 °C for 48 h. The cell growth of each strain was monitored by measuring its turbidity at 660 nm for 96 h