Fig 2. Immunoblot of RpoS in strains E2348/69 and LRT9.

Total protein was extracted from bacteria grown in minimal medium supplemented with a limited concentration of Pi (0.2 mM KH₂PO₄) and immunoblotted against RpoS and RpoD (σ⁷⁰) antibodies. (A) Representative picture of an immunoblot. (B) Quantification of RpoS normalized against RpoD for each strain. 1, MC4100; 2, LRT9; 3, LRT9 rpoS∷Tn10; 4, E2348/69; 5, E2348/69 rpoS∷Tn10. Each bar corresponds to the mean of at least three independent experiments ±SEM. Asterisks indicate statistical difference with p < 0.001 (Students’ t test).