RpoS-dependent phenotypes in MC4100 stocks and the role of rssB. (A) 10 μl patches of strains MC4100TF, MC4100BS, MC4100BS rssB::Km, MC4100BS rpoS::Tn10 and MC4100TF transformed with plasmid pBS28 (prssB+) were grown on LB-agar, TGP+X-P plates and TAP plates (minimal medium supplemented with acetate as the sole carbon source). Bacterial patches in LB-agar were stained with iodine to measure glycogen accumulation. (B) Immunoblotting of RpoS in strains MC4100TF, MC4100BS and MC4100BS rssB::Km. Bacteria grown overnight in LB medium were assayed for RpoS level with monoclonal anti-RpoS antibodies.