Oroboros trace flie.DLD

<b>Aim:</b> It is well-established that adult vertebrates acclimatising to hypoxic environments undergo mitochondrial remodelling to enhance oxygen delivery, maintain ATP balance, and limit oxidative stress. However, many vertebrates also encounter oxygen deprivation during embryonic development. The effects of hypoxia on mitochondrial function are likely to be more profound during embryonic development because environmental stress during early life can lead to permanent physiological and morphological changes that can sometimes be inherited by subsequent generations. To this end, we investigated the long-term effects of developmental hypoxia on mitochondrial function in a species that regularly encounters oxygen deprivation during development; the common snapping turtle (<i>Chelydra serpentina</i>). <b>Methods:</b> Common snapping turtle eggs were incubated in 21% or 10% oxygen from 20% of embryonic development until hatching. Once hatched, turtles were reared in 21% oxygen for up to one year, and ventricular mitochondria were isolated by differential centrifugation. Mitochondrial respiration and reactive oxygen species (ROS) production were measured with an Oroboros microrespirometer. <b>Results:</b> Compared to their normoxic counterparts, juvenile turtles from hypoxic incubations had lower levels of Leak respiration, higher P:O ratios, improved oxygen affinity, and reduced rates of ROS production. Interestingly, these same attributes occur in adult vertebrates that acclimatise to high-altitude hypoxia. <b>Conclusions:</b> Developmental hypoxia remodelled turtle mitochondria, leading to improvements in mitochondrial efficiceny, oxygen delivery, and ROS management. We speculate that these adjustments permanently improve snapping turtle mitochondrial hypoxia tolernace, which would be beneficial for this species during breath-hold diving and overwintering in anoxic environments.