Fig. 3.

GD3 ganglioside induced a loss of mitochondrial transmembrane potential. Gangliosides were added at the onset of culture, and cells were stained 6 days later with JC-1 dye reagent (FluoProbes). Cells were analyzed for apoptosis by flow cytometry (Becton Dickinson). In healthy cells, the JC-1 dye formed red fluorescent aggregates that were detected in the FL2 channel. In apoptotic cells, the dye was dispersed in the cell as green fluorescent monomers, detected in the FL1 channel. The dot plot of the X-axis (FL1), which is the log of JC-1 green fluorescent monomers, and the Y-axis (FL2), which depicts red fluorescent aggregates, was obtained by flow cytometry. The apoptotic cells (typically FL1-positive and FL2-negative) are indicated in the bottom-right quadrant.