FIG. 4.

Differential nitrite production by RAW264.7 macrophage cells infected with sonicated and nonsonicated B. anthracis. The Griess reaction assay was used to demonstrate the generation of μM concentrations of nitrite, the oxidation product of NO^·, up to 24 h after sonicated (without exosporium) and nonsonicated (normal, with exosporium) B. anthracis ΔgerH spore (MOI, 1:1) infection of RAW264.7 macrophage cells. Black bars represent RAW264.7 cells infected with sonicated B. anthracis ΔgerH spores. White bars represent RAW264.7 cells infected with nonsonicated B. anthracis ΔgerH spores. Data are representative of three independent experiments. *, significance at P < 0.05 compared to control.