FIG. 2.

Scanning electron photomicrographs of in vitro-cultured human colonic tissues infected with the EAEC strain 042 (A), the pet mutant strain JIF1 (B), and the complemented strain JIF2 (C) for 8 h, and of uninoculated colonic tissue (D). All of these tissue sections derived from the same intestinal biopsy specimen. For the tissues shown in panels A and C the surface of the colon is markedly abnormal, as manifested by increased crypt apertures (white arrowheads), prominent mucosal crevices (white arrow), goblet cell pitting (black arrowhead), and rounding of epithelial cells (black arrow). Bars, 50 μm.