FIG. 3.

(A) Induction of HeLa rounded-cell phenotype in cocultures with different strains of A. hydrophila SSU. HeLa cells were cocultured for 90 min with the A. hydrophila SSU Δact mutant (column 1) and Δact ΔvasH mutant (column 2) or cultured alone (noninfected HeLa cell control; column 3) in direct bacterium-host cell contact (II) or by using transwell inserts (III). Supernatants from cocultures in direct cell-to-cell contact were collected after 90 min and used as preconditioned media on fresh HeLa cell cultures (IV). The initial morphology of HeLa cells at 0 min is shown in row I, and that of noninfected HeLa cells (control) in column 3. Original magnification, ×400. (B) Quantification of G- and F-actin by Western blot and densitometric analyses. HeLa cells in direct contact with different strains of A. hydrophila SSU were harvested after 90 min of coculture. Cells were lysed and processed as indicated in Materials and Methods. The bar graph represents percentages (means ± standard deviations) of G- and F-actin in HeLa cells infected with different mutant strains from three independent experiments, and the Western blot image is representative of all of them.