Ultrastructural features of knobs in KAHRP mutant cell lines. Transmission electron micrographs of erythrocytes infected with (A) 3D7-K119, (B) 3D7-K245, (C) 3D7-K362, (D) 3D7-K405, (E) 3D7-K530, (F) 3D7-K589, (G) 3D7-K(re), and (H) 3D7 (parental strain). Arrowheads indicate knob formation. Insets show a higher magnification of the areas of each cell shown in panels A, D, and E.