FIG 2.
Overproduction of TrpS counteracts HipTO127. (A to C) Growth curves of strains of E. coli MG1655 harboring pSVN1 (pBAD33::hipTO127) (A), pSVN135 (pBAD33::hipTHi) (B), and pSVN129 (pBAD33::hipTTa) (C) or the empty pBAD33 vector combined with pSVN37 (pEG25::trpS) or the empty high-copy-number pEG25 vector, as indicated. Cells were grown in LB medium supplemented with the appropriate antibiotics. Overnight cultures were diluted and grown exponentially for at least 3 h until the doubling time appeared constant. The pBAD promoter of the pBAD33 derivatives was induced by arabinose (0.2%) at an OD600 of ≈0.3 (red arrow). The PA1/O4/O3 promoter of the pEG25-derived plasmids was induced by the addition of IPTG (200 μM; green arrow) 1.5 h later. Data points represent mean values from at least two independent experiments, and error bars indicate standard deviations.