Effects of environmental anoxia and different periods of reoxygenation on oxidative balance in gills of the estuarine crab Chasmagnathus granulata.
ABSTRACT We investigated the effects of anoxia (8 h) and different periods of reoxygenation (20 and 40 min) on the oxidative balance in anterior and posterior gills of the crab Chasmagnathus granulata. Enzyme activity of catalase and GST was increased in the gills of the animals submitted to anoxia, and SOD activity was decreased. These enzymes returned approximately to control levels during the anoxia recovery time. These results demonstrated enzyme activities change with variations in environmental oxygen levels. The posterior gills showed a higher antioxidant enzyme activity than anterior gills. In the gills, there were no changes in the non-enzymatic antioxidant system (TRAP) during anoxia. On the other hand, during anoxia recovery, an increase of TRAP in both gills was observed. Anoxia does not change lipid peroxidation (TBARS) in the gills. During anoxia recuperation, an increase in levels of TBARS was observed. Thus the results demonstrate that C. granulata has a similar strategy of preparation for oxidative stress as observed in other intertidal species, enabling the crabs to survive in an environment with extreme variations in physical and chemical characteristics, such as salt marshes.
- SourceAvailable from: Gustavo A Lovrich[Show abstract] [Hide abstract]
ABSTRACT: Environmental and physiological variations influence the steady-state concentration of free oxygen radicals in cells. Because of the seasonal life cycle of Lithodes santolla in the Beagle Channel, a baseline study of the antioxidant physiological variations along the seasons is necessary for a better understanding of its ecophysiology. The aim of this study was to evaluate the seasonal variations in gills, haemolymph, muscle and hepatopancreas of the: i) enzymatic activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione transferase; ii) ascorbic acid and total glutathione; iii) lipid peroxidation and protein oxidation; iv) glucose, proteins and pH. Seasonality found in the antioxidant defense system of L. santolla from the Beagle Channel acts in a collaborative way during the most relevant life cycle phases (reproduction and molting), avoiding a long term oxidative stress. The antioxidant system also shows changes in the enzymatic activities likely caused by the environmental factors, such as low temperatures during winter and spring seasons. Copyright © 2014. Published by Elsevier Inc.Comparative Biochemistry and Physiology - Part A Molecular & Integrative Physiology 11/2014; 181. DOI:10.1016/j.cbpa.2014.11.016 · 2.37 Impact Factor
- Bioenergetics, 03/2012; , ISBN: 978-953-51-0090-4
- [Show abstract] [Hide abstract]
ABSTRACT: Jumbo squid (Dosidicus gigas) is a large oceanic squid endemic off the Eastern Tropical Pacific that undertakes diel vertical migrations into mesopelagic oxygen minimum zones. One of the expected physiological effects of such migration is the generation of reactive oxygen species (ROS) at the surface, promoted by the transition between hypoxia and reoxygenation states. The aim of this study was to investigate the energy expenditure rates and the antioxidant stress strategies of juvenile D. gigas under normoxia and hypoxia, namely by quantifying oxygen consumption rates, antioxidant enzyme activities [including superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST)], heat shock protein expression (Hsp70/Hsc70), and lipid peroxidation [malondialdehyde (MDA) levels]. A high significant decrease (68%) in squid's metabolic rates was observed during hypoxia (p <0.05). This process of metabolic suppression was followed by a significant increase in Hsp70/Hsc70 expression (p < 0.05), which may be interpreted as a strategy to prevent post-hypoxic oxidative damage during the squid's night upwards migration to the surface ocean. On the other hand, in normoxia, the higher SOD and CAT activities seemed to be a strategy to cope with the reoxygenation process, and may constitute an integrated stress response at shallower depths. GST activity and MDA concentrations did not change significantly from normoxia to hypoxia (p > 0.05), with the latter indicating no enhancement of lipid peroxidation (i.e. cellular damage) at the warmer and normoxic surface waters. The understanding of such physiological strategies that are linked to oxygen deprivation and reoxygenation phases may provide valuable information about how this species is quickly responding to the impacts of environmental stressors coupled with global climate change.Deep Sea Research Part II Topical Studies in Oceanography 01/2012; 95. DOI:10.1016/j.dsr2.2012.10.001 · 2.76 Impact Factor