FIG 5.

The RSP2 protein influences the motility of strain SL1344(R27) and the conjugation of the R27 plasmid. (A) Effect of the rsp2 allele on the motility of strain SL1344(R27). The motility of the different strains was measured as the halo diameter of the different colonies growing on motility agar. The results are the means of three independent experiments. Standard deviations are shown by the error bars. Statistical analysis showed significant differences, analyzed by unpaired two-sided Student’s t test (*, P value < 0.0001). (B and C) The RSP2 protein binds to the flagella of strain SL1344(R27). Immunogold electron microscopy of cells from strain SL1344 carrying R27 RSP2-Flag (B) or SL1344(R27 Δrsp2) (C) using monoclonal anti-Flag antibodies and goat anti-mouse IgG conjugated to 12-nm gold particles. Arrows point to the RSP protein associated with the flagella in panel B and only to the flagella in panel C. Bars represent 2 μm. (D and E) Effect of the rsp2 allele on the conjugation frequency of the R27 plasmid in liquid (D) and solid (E) media, respectively. The data shown are the means plus standard deviations of three independent experiments. Statistical analysis showed significant differences, analyzed by unpaired two-sided Student’s t test (in panel D, *, P value = 0.0082; **, P value = 0.0095; in panel E, **, P value = 0.0428).