HeLa cells treated with either 10 mM 2DG for 6 hours, 1 µM ABT-263 for 3 hours, or 2DG for 3 hours before adding ABT-263 for an additional 3 hours, or left untreated. a, Cells were fixed for electron microscopy (see Method). Three cells from each treatment group were examined closely for the length of mitochondria. We did not observe a single instance of ruptured mitochondrial outermembranes. b, From each cell, a minimum of 12 mitochondria were randomly chosen for measurement. c, Average lengths of mitochondria became shorter with treatments containing ABT-263 (mean +/− std dev ). Since ABT-263/737 binds to Bcl-2 family members, which are known to be involved in mitochondrial fusion/fission, ABT may have altered the balance of mitochondrial fusion/fission to the fission side (p = 0.0001, 95% confidence interval of this difference: from 14.5407 to 37.2513; unpaired t-test).