Fig. 9. Morphological analysis and DNA staining of A20 B-lymphoma cells treated with cell-permeable ceramides. (A) Cells were incubated with 100 µM C2-ceramide for 16 hours, stained with PI and analyzed by confocal microscopy. As a comparison, non-treated cells were permeabilized with methanol (NT, Met-OH) and stained with PI (control, permeabilized). Phase contrast and fluorescence images from the same optical section are shown. The bar shown in white is equivalent to 13 µm. All images are shown at the same magnification. Alternatively, cells untreated (B) or treated with 100 µM C2-ceramide (C) for 16 hours were analyzed by electron microscopy. Necrotic C2-ceramide- (C) treated cells were both characterized by disruption of the nuclei and abundance of vacuolar structures. The black bar shown for untreated cells (B) is equivalent to 5 µm. The image in panel C is shown at the same magnification.