Figure 4.

Influence of induced O, P gene expression on cell growth at 42 °C. All the strains were made by transforming hosts 594 or 594 dnaB-GrpD55 with pcIpR-(‥)-timm plasmids that included the cloned O, P DNA fragment, and selecting the transformants on LBAmp50 agar (medium composition is described in footnote to Table 3). The plasmid inserts in each CFU employed were verified by DNA sequence analysis. Cells were inoculated from overnight cultures grown up overnight in LBAmp50 broth and then 0.4 mL of culture was added to triplicate 20 mL fresh LB cultures that were incubated at 30 °C for ~30 min to reach an A575 = 0.1. Upon reaching an absorbance of 0.1 the cultures were transferred to a shaking 42 °C water bath. Aliquots were sampled every 30 min for 3 h. The average absorbance is shown, with a standard error for each culture time of less than 5% the averaged absorbance value.