Blier 2019 MiP2019
Delineating the physiological and biochemical causes of aging process in the animal kingdom is a highly active area of research not only because of potential benefits for human health but also because aging process is related to life history strategies (growth and reproduction) and to responses of organisms to environmental conditions and stress. In this presentation, I advocate studying bivalve species as models for revealing the determinants of species divergences in maximal longevity. This taxonomic group includes the longest living metazoan on earth (Arctica islandica), which insures the widest range of maximum life span when shorter living species are also included in the comparative model. This model can also be useful for uncovering factors modulating the pace of aging in given species by taking advantages of the wide disparity of lifespan among different populations of the same species. For example, maximal lifespan in different populations of A islandica range from approximately 36 years to over 500 years.
We compared membrane fatty acid as well as metabolic capacities (respiration rates) and ROS production from mitochondria of five species of bivalves and different populations of A islandica. Fatty acid profiles were determined by Gas Chromatography with FID detection, while oxygen consumption and peroxide efflux were assayed by high resolution respirometry (O2K) and fluorescence detection with Amplex Red®.
Our analysis revealed that either regulation or tolerance to oxidative stress is tightly correlated to longevity of species [1,2,3] but when comparing different populations of A islandica, the relationship of membrane fatty acid composition or Peroxidation Index with maximum lifespan vanishes . This led us to conclude that mitochondrial membrane robustness to ROS attack is required for a species to be able to reach long lifespan but it is not sufficient at the population level to express this life history trait.
Labels: MiParea: Respiration Pathology: Aging;senescence Stress:Oxidative stress;RONS Organism: Molluscs
HRR: Oxygraph-2k, O2k-Fluorometer
- Dept Biology, Univ Québec à Rimouski, Rimouski QC, Canada. - [email protected]
Figure 1: Relationships between (A) %docosahexaenoic acid, (B) %peroxidation-sensitive polyunsaturated fatty acids, (C) peroxidation index, and maximum reported longevityfor five model bivalve species. Peroxidation index is also plotted against the shared maximum longevity (D), the longevity known to be attained in at least two populationsof the species. Data for gill mitochondrial membranes (black symbols and solid lines) and cellular debris phospholipids (white symbols and dashed lines) are presented withtheir best fitting model. Values are means ± _SEM, n = 6 to 9 individuals per species (for details see ).
Figure 2: Peroxidation index in mitochondria from A. islandica populations ranked from shortest- to longest-lived. Values are means _ SEM. Letters denote significant (p _ 0.05) differences between populations for gills (filled bars) and mantle (empty bars) tissues, while asterisks indicate significant differences between tissues (**p ≤ 0.05; for details see ).
- Blier PU, Abele D, Munro D, Degletagne C, Rodriguez E, Hagen T (2017) What modulates animal longevity? fast and slow aging in bivalves as a model for the study of lifespan. Semin Cell Dev Biol 70:130-40.
- Munro D, Blier PU (2012) The extreme longevity of arctica islandica is associated with increased peroxidation resistance in mitochondrial membranes. Aging Cell 11:845-55.
- Munro D, Pichaud N, Paquin F, Kemeid V, Blier PU (2013) Low hydrogen peroxide production in mitochondria of the long-lived arctica islandica: Underlying mechanisms for slow aging. Aging Cell 12:584-92.
- Rodríguez E, Dégletagne C, Hagen TM, Abele D, Blier PU (2019) Mitochondrial traits previously associated with species maximum lifespan do not correlate with longevity across populations of the bivalve arctica islandica. Front Physiol 10:946.