48.3 Saturday, Jan. 5 Low hydrogen peroxide production in mitochondria of the long-lived Arctica islandica: underlying mechanisms of increased longevity MUNRO, D.*; PICHAUD, N.; PAQUIN, F.; BLIER, P.U.; Univ. du Québec à Rimouski, Canada; Univ. of New South Wales, Sydney, Australia; Univ. du Québec à Rimouski, Canada; Univ. du Québec à Rimouski, Canada email@example.com
The inverse correlation between lifespan and mitochondrial ROS production rate observed in vertebrates represents a major pillar of the oxidative stress theory of aging. Bivalve molluscs are routinely exposed to environmental constraints such as microbial H2S, anoxia/reoxygenation and temperature variations that would normally elicit oxidative stress in mammals. Hence, they represent an interesting taxon to challenge the existence of this correlation in remote phyla. We compared the mitochondrial H2O2 production rates between the longest-lived metazoan, the bivalve Arctica islandica (maximum reported longevity = 507 years) and two taxonomically related short-lived species of comparable size. We also compared the oxygen consumption of intact mitochondria and the enzymatic activity of different complexes of the electron transport system. Mitochondria of A. islandica produced significantly less H2O2 than those of the two short-lived species in different conditions of mitochondrial respiration which includes forward, reverse, and convergent electron flow. A reduced complex I content in A.I. can provide a partial explanation for the results during reverse electron flow. However, a lower electron flux control, leading to lower degree of electronic reduction of complex I and III, as well as a lower activity of complex II in A.I. may yield another explanation for the results obtained during forward and convergent electron flow, respectively. Overall, our study suggests that the relationship between ROS production rate and longevity may be generalized among metazoan and the adaptative mechanisms to achieve it may be remarkably conserved.