FIG. 4.

Induction of local actin reorganization and membrane protrusion at the site of O. tsutsugamushi infection. (A) HeLa cells infected with O. tsutsugamushi for 10 min or 30 min were stained with Alexa Fluor 594-conjugated phalloidin to detect actin filaments (red). Some of the cell-associated bacteria (arrowheads) induced local rearrangements of the actin cytoskeleton surrounding O. tsutsugamushi (green). Bars, 10 μm. (B) Scanning electron microscopy examination of the surface interaction of O. tsutsugamushi with HeLa cells. HeLa cells on glass coverslips were infected for 10 min and processed for scanning electron microscopy. The arrowheads indicate membrane protrusions surrounding the cell-associated bacteria.