Competition studies, exponential growth rates, and ribo-some profiles of MG1655 (wild type) and four pseudorevertant isolates of the ΔrluD::kan mutant. (A) Growth competition studies were done as described previously (Gutgsell et al. 2000). MG1655 (wild type) (closed squares), four individual pseudorevertant isolates (open and closed triangles and circles). Exponential growth rates were done as described in Materials and Methods. Doubling times were determined as described in Figure 2. Each plot consisted of seven to nine time points. Doubling times were the average of two determinants. (B) Ribosome profiles were performed as described in Materials and Methods. Wild-type, pseudorevertant, and mutant cells were lysed at 6 mM Mg++ and gradients were run at 10 mM Mg++. Twelve A260 units were layered onto 14%–32% sucrose gradients and centrifuged at 22,000 rpm for 19 h at 4°C.
