FIG. 5.

Electron photomicrograph demonstrating an intravacuolar rickettsia with morphology consistent with phagolysosomal digestion (vacuolar membrane, large arrow). Note the increased waviness of the rickettsial outer membrane (arrowhead), increased electron density of the rickettsial nucleoplasm (small arrows), dilation of the periplasmic space (p), and overall loss of bacillary morphology. An adjacent, intracytosolic rickettsia appears healthy by comparison (asterisk). Anti-OmpB antibody-treated rickettsiae at 24 h after infection of SVEC endothelial cells are shown. Bar, 0.25 μm.