Figure 6.

Cell death and DNA fragmentation induced by the Ca²⁺ ionophore A23187. Five-hundred-microliter aliquots of cultures containing nascent TEs were pelleted by centrifugation three times and resuspended in either standard culture medium containing 1 mm CaCl₂ (control and A23187) or medium lacking added CaCl₂ (A23187, low [Ca⁺⁺]) before treatment with 0.1 mm A23187. The percentage of dead cells was determined 4 h later using fluorescein diacetate; the percentage of cells exhibiting DNA fragmentation was determined 7 h after treatment using TUNEL. Error bars represent the se of two samples treated in parallel.