Strains CLT254, as a source of greA::cat, and CLT255, as a source of greB::kan, were obtained from Dr. R. Weisberg. Plasmid pBW, containing the rrnB P1P2 region spanning from –235 to +237 bp (using P1 as a reference) was constructed by removing a 370-bp rrnB T1T2 terminator ...