Impact of <i>P. aeruginosa</i> on viability on RAW 264.7 cells.

<p><b>A</b>) Phase overview of cell morphology, uninfected cells (RAW) and resistant cells (ResRAW - see text) were exposed to <i>P. aeruginosa</i> (MOI 10) and returned to culture for 6 or 24 h. Note the major change in cell shape and size of the wt cells upon exposure to <i>P. aeruginosa</i>. The resistant cells appear unaffected over the same time period. <b>B</b>) Actin cytoskeleton, stained with rhodamine-phalloidin after fixation. Uninfected cells compared to resistant cells after exposure to <i>P. aeruginosa</i> (MOI 10) and reculture for 6 or 24 h. Note the enlargement of wt cells and appearance of a subset of cells with double nuclei (shown by an arrow). The nuclei were stained blue with DAPI. For the panels at the right, phalloidin staining was omitted and the images were viewed with the red filter. <b>C</b> and <b>D</b>: MTT assays to quantitate cell number. Uninfected cells compared to cells exposed to <i>P. aeruginosa</i> and then recultured over 4 days for both naïve RAW 264.7 (<b>C</b>) and resistant cells (<b>D</b>). In both cases, cells were exposed to <i>P. aeruginosa</i> for 1 h before washing and return to culture. Activity measurements (per culture) were normalized to values for cells cultured without PAO1 over four days.