The morning burst: Shifting daily patterns of ATP production in Drosophila and temporal windows for their improvement in ageing

Mitochondria produce energy for cell function via adenosine triphosphate (ATP) and are regulated by a molecular 24h clock. Here we use Drosophila melanogaster to reveal shifts in whole animal ATP production over 24h, showing a marked peak in the morning that declines around midday and remains low from then through to the following morning. Mitochondrial membrane potential and ATP production has been shown previously to improve after long wavelength exposure, but apparently not at all times. Hence, to explore this further we exposed flies to 670nm at different times. Exposures between 08.00 and 11.00 resulted in a significant increase in ATP, while exposures at other times had no effect. Within the morning window, not all times were equally effective, however, 670nm exposure mid-morning when ATP production was maximal did not increase ATP, possibly because mitochondria lacked spare capacity at this time. Hence, in the morning there is a complex dynamic relationship between long wavelength light and mitochondria. Mitochondrial function and the influence of long wavelengths are conserved across species from fly to human, and determining the time points for light administration to improve function in ageing and disease is of key importance. Our data progress this search and reveal the outline of these times.