Fig. 6

Efficient escape from the ruptured CV and the lysed cysts requires flagellum-based motility. a Scanning electron micrographs of WT V. cholerae and its flaA- and pomB-deficient derivatives, which lack the major flagellin and cannot rotate their flagellum, respectively (as schematized below the images). Scale bar: 1 µm. b Close-up view of confocal scanning images of CVs (transmitted light) that were colonized by each one of the three GFP-tagged strains shown in a. The scanning speed was lowered for these experiments to visualize the fast movement of WT V. cholerae inside the CV. See also Supplementary Movies 2 to 4 for dynamics of intra-vacuolar WT, ΔflaA, and ΔpomB bacteria. Scale bar: 5 µm. c Escaping from the lysed amoebal host and spreading requires flagellum-based motility. A. castellanii was infected with a 1:1 mixture of WT (dsRed-tagged) and non-motile flaA-minus (GFP-tagged) bacteria. Time-lapse microscopic imaging of a co-infected amoeba was started at 15 h p.p.c and followed for more than six hours (time is indicated on the right). Still images derived from the recorded movie (Supplementary Movie 5) are depicted and show (from top to bottom) the colonized trophozoite before and after encystation, after rupture of the CV, and after cyst lysis. Scale bar: 10 µm