FIG. 5.

Electron micrographs of mock-infected human DRG axons. Coverslips with explanted DRG cultures in situ were fixed and processed for TEM. Areas containing mid- and distal regions of axons were sectioned, collected on copper grids, and examined using a Philips CM120 BioTWIN transmission electron microscope at 100 kV. (A) An axonal varicosity (arrow) is an expanded region of the axon showing a disruption in microtubule bundles and contains numerous heterogeneous vesicles (arrowhead). Growth cones (B and C) (arrows) at the axon terminus are visible among the distal axons and have a central region containing a high concentration of heterogeneous vesicles (clear and dense core vesicles) (arrowheads) and a few microtubules, which are continuous with the axon that precedes the growth cone. Bars, 1 μm.