Fig. 1.

a Representative histograms of flow cytometry experiments demonstrating that the mean fluorescent intensity of oxidized MitoSox is greater in cultured Mus musculus fibroblasts than in Peromyscus leucopus cells. MitoSox staining was used to measure mitochondrial O₂⁻ generation (for methods, see Mukhopadhyay et al. 2007a, b). Cell debris (low forward and side scatter), dead (Sytox Green and annexin V-positive) and apoptotic cells (annexin V-positive) were excluded from the analysis (Mukhopadhyay et al. 2007a, b). b Summary data for MitoSox fluorescence intensities in cultured human, P. leucopus and M. musculus fibroblasts. Cells were grown in 96-well plates and buildup of MitoSox fluorescence was assessed using a Tecan Infinite M200 fluorescent plate reader as described in Csiszar et al. (2007c). Hoechst 33258 fluorescence representing DNA content/cell mass was used for normalization. Data are means ± SEM (n = 8 in each group), * P < 0.05. vs human, # P < 0.05 vs P. leucopus