FIG. 6.

Immunoblot analysis of δ, σ^A, and β subunits during growth. A909, AJ200, and AJ8D3 were grown to lag (LA) (OD₆₀₀ = 0.1), early log (EL) (OD₆₀₀ = 0.3), late-log (LL) (OD₆₀₀ = 0.3) and stationary (SA) phases (OD₆₀₀ = 1.0). Lysates were normalized for total protein (10 μg) and subjected to SDS-PAGE. Western blots were performed by using antisera directed against δ (A), σ^A (B), and β (C). Protein levels were probed by using polyclonal sera raised against the recombinant protein. (D) Estimation of δ levels. A total of 10 μg of A909 (1), AJ200 (2), and AJ8D3 (3) lysates were loaded together with 100 ng, 50 ng, 25 ng, 10 ng, and 5 ng of purified δ. Blots were probed with antisera directed against δ. Immunoreactive bands were detected by using an infrared imager after incubation with a rabbit anti-IgG infrared-labeled secondary antibody, and band intensity was compared between strains. rδ, recombinant delta protein.