Seasonality of energetic functioning and production of reactive oxygen species by lugworm (Arenicola marina)mitochondria exposed to acute temperature changes

Abstract

SUMMARY The influence of seasonal and acute temperature changes on mitochondrial functions were studied in isolated mitochondria of the eurythermal lugworm Arenicola marina (Polychaeta), with special emphasis on the interdependence of membrane potential and radical production. Acclimatisation of lugworms to pre-spawning/summer conditions is associated with rising mitochondrial substrate oxidation rates, higher proton leakage rates, elevated membrane potentials, and increased production of reactive oxygen species (ROS)in isolated mitochondria, compared with mitochondria from winter animals. However, a high ROS production was compensated for by higher activities of the antioxidant enzymes catalase and superoxide dismutase, as well as lower mitochondrial densities in summer compared with winter animals. In summer animals, a higher sensitivity of the proton leakage rate to changes of membrane potential will confer better flexibility for metabolic regulation(mild uncoupling) in response to temperature change. These seasonal alterations in mitochondrial functions suggest modifications of energy metabolism in eurythermal and euryoxic organisms on intertidal mudflats during summer. In winter, low and less changeable temperatures in intertidal sedimentary environments permit higher respiratory efficiency at low aerobic metabolic rates and lower membrane potentials in A. marinamitochondria.

Change in redox state and heat shock protein expression in an Indian major carp <i>Cirrhinus cirrhosus</i> exposed to zinc and lead

“…The resulting ROS exceed primary scavenging capacity of an organism and attack different cellular components, such as nucleic acids, cytoplasmic proteins, lipids, and membranes (Dröge, 2002;Valavanidis et al, 2006). ROS production in cells, especially in the mitochondria and peroxisome, has been found to be increased in exercised mammalian muscle, stressed bivalve gills, chicken muscles, lugworm and cultured cells as compared with non-stressed control tissue (Keller et al, 2004;Heise et al, 2003). Increase in oxidative process during high concentration of heavy metal or any other pollution related stress causes ROS accumulation, and cellular protection against such damage is achieved mainly by enzymes such as SOD, CAT, GPx or GRd (Lin et al, 2015;Das et al, 2017).…”

Physiological ageing in a temperate and a polar swimming scallop

“…Measurements of the H 2 O 2 generation rate of Aequipecten opercularis mitochondria were performed with a Shimadzu (RF-1501) fluorometer at the Port Erin Marine Laboratory, as described in detail by Philipp et al (2005b) for Laternula elliptica. Both H 2 O 2 generation rates and oxygen consumption rates were measured in parallel and related to mitochondrial protein content (for details see Keller et al 2004).…”

Advances in Stress Physiology and Bioenergetics of Farm Animals: An Overview

“…The increase in ROS reflects increased level of thermal stress. Keller et al, (2004) also observed that exposure of animals to elevated temperatures accelerated mitochondrial respiration and increased mitochondrial ROS formation. ROS, being cellular toxicants (Davidson et al, 1996), can be induced through hyperthermia (Flanagan et al, 1998).…”