FIG. 5.

Time dependence of DNA content and cytopathic effect of HeLa cells treated with bacterial sonicates with CDT activity. Compared to control cells (A), cells treated with sonicates from H. hepaticus (D, G, and J) showed a progressive increase in the fraction of cells with a DNA content of 4 N, with a maximal effect being reached 72 h after sonicate addition (J). Compared to control cells (B and C), cells treated with sonicates from an E. coli strain harboring the cloned H. hepaticus cdt locus showed a progressive increase in size with accumulations of polymerized actin (E, H, and K) and progressive nuclear abnormalities (F, I, and L). These changes in morphology mirrored the progressive cell cycle block observed by flow cytometry. Magnification, ×400. PI, propidium iodide.