Fig. 2.

Ultrastructure of A. phagocytophilum (strain ApMuc01c) in IRE/CTVM20 cells examined by transmission electron microscopy. (A) Vacuole (black arrow) containing single bacteria (N: nucleus). (B) A. phagocytophilum inclusion in a tick cell showing electron-dense forms; note the double polar dots possibly representing a condensed nucleoside (black arrows). (C) Highly electron-dense organisms (black arrow) in a vacuole. (D) Electron-dense (black arrows) and reticulate forms (white arrow), which were visible in two vacuoles of an infected cell; some individual bacteria are surrounded by a double membrane. (E) and (F) Vacuoles containing electron-lucent reticulate organisms (white arrows); note the electron-dense pinpoint structures in some bacteria. Scale bars in all pictures represent 2 μm.