The daf-2(e1370) allele causes a higher mitochondrial membrane potential and enhanced respiratory capacity. (a) Increased accumulation of the fluorescent probe DASPMI inside energized daf-2(e1370) mitochondria. Fluorescence intensity of DASPMI in energized and uncoupled isolated mitochondria of wild-type (WT) and daf-2(e1370). Fluorescence emission over the 2 min interval was averaged for each energetic state. Displayed values are means ± standard error of mean for three replicate cultures. The increase of DASPMI fluorescence is proportional to the amount of dye taken up by the mitochondria which itself is proportional to the membrane potential (Mewes and Rafael ). (b) Higher oxygen consumption in the presence of adenosine diphosphate or uncoupler by daf-2(e1370) mitochondria. The assay was performed on two replicate cultures; since no age-dependent differences were noticed, mitochondrial respiration rates were averaged per strain over a 9-day time span. Paired t-tests were performed in within-strain comparisons, unpaired t-tests were performed in between-strain comparisons; * P < 0.05, ** P < 0.01 and *** P < 0.001.