Fig 6.

SecA is essential. (A) The strains LVS, TetOn (FTRp-secA; TetR), and TetOff (FTRp-secA; revTetR) were streaked onto chocolate agar plates that contained either 0 or 500 ng ml⁻¹ ATc. The plates were allowed to incubate for 72 h at 37°C. (B) Growth curves of either TetOn or TetOff were performed in media containing 0 or 100 ng ml⁻¹ ATc. The absorbance at OD₆₀₀ was measured every 15 min for 50 h. The growth curves were plotted on a log₁₀ scale. There was a significant difference in final growth as measured by absorbance at OD₆₀₀, with TetOn being unable to reach WT levels of growth without ATc (P < 0.01) and TetOff unable to reach WT levels with ATc (P < 0.01).