Haemacolor staining of PAM whether or not exposed to 0.025 μg/mL of DON. Figure A shows porcine macrophages not exposed to DON, whereas Figure B shows DON exposed macrophages with marked membrane ruffling. Figures C–F show fluorescence microscopic pictures of actin filament arrangement in PAM either treated with cell medium, 0.025 μg/mL of DON, 10 μM of the ERK1/2 inhibitor U0126 ethanolate in combination with 0.025 μg/mL of DON or with 50 ng/mL of the ERK1/2 activator PMA, for 24 h. Control macrophages (C) and macrophages exposed to U0126 ethanolate in combination with DON (E) demonstrated a normal distribution of F-actin. DON (D) and PMA (F) exposed macrophages demonstrated increased formation of membrane ruffles (indicated by white arrows). (A color version of this figure is available at www.vetres.org.)