Figure 1: Simultaneous monitoring of mitochondrial membrane potential and morphology in INS-1E 𝛽   cell under transient oxidative stress. Real-time imaging of INS-1E cells by simultaneous fluorescence recordings of mitochondrial potential (Δ Ψ 𝑚 ) by TMRE (a and c) and mitochondrial morphology by Δ Ψ 𝑚 -independent mito-eYFP (b and d) as described [2]. (a), Signals recorded before oxidant exposure (before-stress), during the 10 min 200 μM H2O2 exposure (stress), and after neutralization of extracellular H2O2 by the addition of 100 U/mL catalase (after-stress). (b), Corresponding mitochondrial morphology monitored simultaneously with Δ Ψ 𝑚 shown in (a). (c) and (d) show control nonstressed cells.