Light-induced ATP synthesis is reduced in <i>ppr</i> mutant eyes.

<p>(A) Relative mtRNA levels, normalized to precursor RNA transcribed from the heavy strand (+) of the mitochondrial genome, in control and <i>ppr</i>^<i>A</i> third instar larvae. (B) Relative mtDNA content, normalized to nuclear DNA, in control and <i>ppr</i>^<i>A</i> third instar larvae. (C) Relative mtRNA levels, normalized to nuclear RNA RP49. (D) Activities of mitochondrial electron transport chain (ETC) protein complexes (CI, CII, CIII, CIV) and Citrate synthase (CS) from third instar larval extracts. Genotypes shown are control, <i>ppr</i>^<i>A</i> and <i>ppr</i>^<i>A</i>; genomic rescue (CH322-75O21). ETC complex activity was normalized to CS, and data are expressed as percentage of the activity detected in controls. (E) O_<b>2</b> consumption assayed by polarography. O_<b>2</b> consumption was measured from isolated third instar larvae-derived mitochondria in the presence of CI-specific substrates. State III is the ADP-stimulated O_<b>2</b> consumption rate; State IV represents the ADP-limited O_<b>2</b> consumption rate; RCR is the Respiratory Control Ratio (state III rate / state IV rate). (F–G) Relative ATP levels from control and <i>ppr</i>^<i>A</i> third instar larval extracts (F) and adult eyes (exposed to 1 h light, 1,800 Lux) (G). (H) Relative change in ATP levels in adult heads upon 1 h exposure to light (1,800 Lux). In A–H, error bars represent mean ± standard deviation (SD); statistical significance was determined using a two-tailed Student’s <i>t</i> test (<i>p</i>-values: *** < 0.001, ** < 0.01, * <0.05).