Figure 6. Loss of mitochondrial function was an early event in ageing C. elegans. (A-E) At 2 d, the absolute difference between MAPR at 15°C, 20°C, and 25°C is greatly reduced versus 0d in animals with GFP-labelled mitochondria, with a range of respiratory substrates. At 2 d, 25°C was not significantly greater than 15°C or 20°C with any respiratory substrate (P >0.05). There was a significant reduction in MAPR over time (P<0.001), primarily at 0d – 2d with 25°C (all substrates P <0.05 – P <0.001) and 20°C (all substrates P<0.05 – P<0.001) but not 15°C (all substrates P >0.05). This same loss of MAPR was observed in wild-type C. elegans at 20°C (GS 0 vs. 2 d, P <0.05 and all substrates P< 0.001 0 vs. 4 d). Data represent mean ± SEM, * P <0.05; **P <0.01; ***P <0.001. (G) Assessment of mitochondrial membrane potential using JC-10 shows that mitochondrial membrane potential is preserved at 15°C (> 96h) whereas at 25°C, mitochondrial membrane potential is lost early in the lifespan (24-48h). Scale bar represents 25 μm.