Fig 1.

(A) Phenotypic analysis of various strains of R. sphaeroides: WS8 (wild-type), SltF1 (ΔsltF), SltF1/sltFΔSP, and SltF1/sltF. The sltF alleles were cloned in vector pIND4 (for details, see Materials and Methods). Swimming assays on soft agar plates were carried out in 0.25% agar supplemented with 100 μM sodium propionate and 1 mM IPTG. The cells were grown under aerobic conditions at 30°C for 48 h. (B) Western blot analysis of the same strains shown in panel A, using anti-SltF gamma globulins. (C) Sensitivity to proteinase K of SltF with or without signal peptide analyzed by Western blotting with anti-SltF gamma globulins. Proteinase K was added where indicated (+). (D) Cell fractionation and osmotic shock were performed as described previously (10). Pellet and periplasmic fractions were analyzed by Western blotting with specific anti-SltF and CheY6 gamma globulins at dilutions of 1:2,500 and 1:300,000, respectively. SDS–12.5% PAGE was used in all cases.