FIG. 1.

EPEC-induced hemolytic activity. EPEC, various deletion mutants, and complemented mutant strains were assayed for their abilities to lyse sheep RBCs as described in the text. Release of hemoglobin was assessed at an optical wavelength of 543 nm by using RBCs incubated in the absence of bacteria as a spectrophotometeric zero. Results from three independent experiments are shown. Error bars, standard deviations.