Fig. 7
Oxidative stress caused by spermidine catabolism is suppressed through genetic or pharmacological enhancement of antioxidant capacity. a, b DHE staining (intensity indicated with heat map) showing ROS levels in fly brains. Note the increased fluorescence intensity in the mutant brains, which can be suppressed by ubiquitous (actin-gal4) or neuronal (elav-gal4) overexpression of GstE1. Quantified in f. Scale bar, 100 µm. c Climbing performance of control, dSms e/e, and dSms e/e flies ubiquitously overexpressing GstE1 at of 2 and 5 DAE (mean ± S.E.M.; each data point obtained from a group of 10 animals, n = 10 experiments). d Fly survival curves (n = 62 for dSms e/e and 66 for GstE1 rescue flies) determined by the age-specific number of live individuals. e Representative traces from ERG recordings showing light-induced depolarization and on/off responses. f–h Quantification (mean ± S.E.M.; n = 10 (dSms e/e, 15 DAE), 10 (dSms e/e, 30 DAE), 11 (actin > GstE1, 15 and 30 DAE) field recordings from 4–5 animals) of on transient (f), off transient (g), and depolarization (h) of ERG at different ages. i DHE staining showing ROS levels in brains of 5 DAE mutant flies raised on antioxidants at different concentrations. See a for staining of untreated mutant flies. j Quantification of ROS levels (n = 12 (control), 12 (dSms e/e), 5 (actin > GstE1), 5 (elav > GstE1), 9 (AD 40 μg ml−1), 5 (N-2-MPG 80 μg ml−1), 5 (N-2-MPG 160 μg ml−1) animals from each group; mean ± S.E.M.) normalized to control brain. k Histochemical analysis of COX activity in brain and flight muscle. Black dashed outline delineates different brain regions. MBr middle brain, Me medulla, La lamina. Scale bar, 100 µm. c Student’s t test; f–h, j One-way ANOVA post hoc Tukey test. **P < 0.01
