From bivalves to birds: oxidative stress and longevity

Abstract

Summary1. The oxidative stress theory of ageing predicts that animals living longer will have less cumulative oxidative damage together with structural characteristics that make them more resistant to oxidative damage itself. 2. Although a general relationship between body size, metabolism and longevity does not exist in marine invertebrates, they are generally characterized by low rates of metabolism and reactive oxygen species (ROS) formation associated with lower antioxidant enzyme activities compared to vertebrates. 3. Birds and mammals have very similar size-affected metabolic rates and their metabolic intensity explains only some of the variation in maximum lifespan potential (MLSP). Within each class, smaller animals have higher rates of metabolism and ROS production and membranes that are more susceptible to oxidative damage and autocatalytic propagation of free radicals than larger ones. 4. Although the high variation in life-history strategies is accompanied by substantial variation in MLSP, there is a consistent positive correlation between rates of ROS formation and antioxidant levels among most animals examined so far for these traits. The consensus of these studies is that ROS and antioxidant levels are inversely related to MLSP. 5. The lack of a clear stoichiometric relation between variables contributing to oxidative stress limits our capacity to infer longevity consequences from measures of pro-oxidant or antioxidant status among or within species.

Physiological responses to self-induced burrowing and metabolic rate depression in the ocean quahogArctica islandica

“…The transient reduction of metabolically derived ROS formation during MRD may have life prolonging effects in the ocean quahog Buttemer et al, 2010). Although A. islandica already features very low in vitro ROS formation under normoxic states 3 and 4 (Buttemer et al, 2010), ROS production in isolated gill tissue was found to be drastically reduced under low oxygen conditions of 5kPa compared with 21kPa and supposedly fully subsides as cellular respiration stops at 0kPa.…”

Analysis of gene expression from theWolbachiagenome of a filarial nematode supports both metabolic and defensive roles within the symbiosis

“…The most probable fitness benefit was an increase in the reproductive lifespan of the worms, since females of O. volvulus (and almost certainly O. ochengi) remain fecund for >10 yr, whereas O. flexuosa is thought to only live for ;1 yr (Plenge-Bönig et al 1995). As reactive oxygen species are one of the principal drivers of aging (Buttemer et al 2010), we propose that the ability of Wolbachia to perform aerobic respiration and to metabolize iron while maintaining an elevated oxidative stress response are key mechanisms that promote infection of somatic tissues in filariae.…”

Micro-scale environmental variation amplifies physiological variation among individual mussels

“…Macromolecular damage in adductor muscle could lead to significant organismal consequences, either by limiting an individual's capacity to perform valve gaping behaviours that might contribute to evaporative cooling or by increasing susceptibility to predation. Adjustments in antioxidant capacity likely stem from changes in the rate of ROS formation, potentially mediated by shifts in mitochondrial volume ( plastic over weeks to months; [61]) or by adjustments in the level of unsaturation of fatty acids in the inner mitochondrial membrane [27,33]. These physiological changes would correspond with changes in overall oxygen utilization or in the leakiness of the inner mitochondrial membrane to protons, respectively.…”

“…We specifically quantify the capacity to prevent oxidative stress, which results from an imbalance between the rate of production of reactive oxygen species (ROS) and the cell's antioxidant capacity. The rate of production of ROS is inherently linked to metabolism [32,33], and it tends to increase when organisms are pushed towards their thermal limits and/or when they are exposed to cycles of hypoxia and reoxygenation [32][33][34][35]. Although mussels' physiologies appear well suited to the oxidative stress potentially engendered by their intermittently warm and hypoxic lifestyle (coinciding when the shell valves are closed at low tide; [36,37]), available data support a role for variation in susceptibility to oxidative stress in setting different thermal tolerance limits among Mytilus congeners [38,39].…”