FIG. 2.

Western blot analysis of RpoS levels in hfq-1 mutant and DsrA-overexpressing strains. Cells were grown at 30°C in LB broth to OD₆₀₀ of 0.5. Total cellular extracts of the strains were electrophoretically separated on a SDS–10% polyacrylamide gel, and electroblotted to a polyvinylidene difluoride membrane. The membrane was probed with rabbit anti-RpoS polyclonal antisera and visualized as described in Materials and Methods. Lanes 1 and 2 contain wild-type cells with either vector (pACYC184) or pDsrA. Lanes 3 and 4 contain isogenic hfq-1 mutants with either vector (pACYC184) or pDsrA. Since long exposures were used to visualize RpoS in the hfq mutant strains, lanes 1 and 2 are beyond the linear range of the Western blot. The position of RpoS is indicated.