Identification of the Raf-HlyAs fusion protein by immunoblotting. Cultures of Salmonella enterica serovar Typhimurium SL7207 carrying the plasmids pMOhly1 (lanes 1 and 3) or pMOhly-Raf (lanes 2 and 4) were grown in BHI medium to a density of 5 × 108 cells per ml (optical cell density OD600 = 1). Supernatant proteins precipitated from 1.5 ml of bacterial culture were loaded in lanes 1 and 2; cellular proteins from 0.15 ml of culture were loaded in lanes 3 and 4. The immunoblot was developed with polyclonal anti C-Raf antibodies. The samplers were prepared as described in Materials and Methods.