Levels of RpoS during growth of strain SPR044 and derivatives of this strain. Cells were grown in M9 minimal medium supplemented with 0.5% myo-inosit under aerobic conditions at 26°C, harvested after 6 h (lane 1), 10 h (lane 2), 14 h (lane 3), 18 h (lane 4), or 24 h (lane 5), and lysed in sample buffer. Equal amounts of proteins in cell lysates were subjected to SDS-PAGE and Western blot analysis with RpoS-specific antiserum. (A) SPR044; (B) SPR244; (C) SPR244(pTrc300); (D) SPR244(pTrcGacS). Molecular masses of reference proteins are given on the right.