Biochemical characterization of the antioxidant system in the scallop Adamussium colbecki, a sentinel organism for monitoring the Antarctic environment

Abstract

The scallop Adamussium colbecki can be profitably used for monitoring Antarctic coastal environments but its utility would be increased if chemical analyses of pollutants were integrated with data on their biological effects. Since oxidative stress is a common pathway of toxicity induced by xenobiotics, a preliminary biochemical characterization was carried out on the antioxidant system of this species and baseline data collected for future assessment of the anthropogenic impact in this remote area. The digestive gland and gills were investigated for levels of glutathione and the activity of several glutathione-dependent and antioxidant enzymes: gluthathione reductase, EC 1.6.4.2; glyoxalase I, EC 4.4.1.5; glyoxalase II, EC 3.1.2.6; gluthathione S-transferases, EC 2.5.1.18; Se-dependent, EC 1.11.1.9 and Se-independent, EC 2.5.1.18 glutathione peroxidases; catalase, EC 1.11.1.6; and superoxide dismutase, EC 1.15.1.1. The same enzymatic activities were measured for comparison in the Mediterranean molluscs Mytilus galloprovincialis and Pecten jacobaeus. Very high levels of glutathione S-transferases were found in the digestive gland of both species of scallop compared to mussels, suggesting the importance of different feeding behaviour among these molluscs. However, catalase activity, much higher in Adamussium colbecki than in the Mediterranean molluscs, may represent a biochemical adaptation to the Antarctic marine environment with high levels of dissolved oxygen. Enzymes from the Antarctic species appeared to be generally more active at low temperatures but, with a few exceptions, their activities increased at higher temperatures

Transcriptional analysis of disk abalone (Haliotis discus discus) antioxidant enzymes against marine bacteria and virus challenge

“…Hence, we introduce all of these antioxidant enzymes that collectively represent a classical antioxidant defense system in disk It has been suggested that varied responses to oxidative stress could be related to the metabolic capacity of the tissues as well as the antioxidant content [4]. Mollusk gills require an efficient antioxidant defense system, since oxygen transfer occurs at the surface of the gill [29,30], thereby it has a greater potential to accumulate excessive ROS. Also, the gill is in continuous contact with water, and it could be infected easily if any pathogenic microorganisms are in the surrounding environment.…”

Effects of dissolved oxygen on survival and immune responses of scallop (Chlamys farreri Jones et Preston)

“…The lower SOD activity at lower DO was not beneficial to depressing the oxidative damage to haemocytes and caused lower THC subsequently. The high levels of SOD at early stage at low DO really represent an adaptation to the oxygen stress [54], while decreased SOD activity at a later stage would render the organisms more susceptible to the oxidative stress related to their environment. Also, lower SOD activity suggests a poor physiological and immunological state of the scallops after a long period of hypoxia.…”

Effect of copper exposure on GST activity and on the expression of four GSTs under oxidative stress condition in the monogonont rotifer, Brachionus koreanus

“…The GSTs are involved in both the transport and biosynthesis of endogenous compounds and cellular defense mechanisms against xenobiotics and oxidative damage by catalyzing the conjugation of reduced glutathione through its cysteine thiol (Regoli et al, 1997;Sheehan et al, 2001). Thus, GST activity has been widely used as a biomarker for detecting oxidative stress in a wide range of organisms including mammals to invertebrates (Yamamoto et al, 2005;Hearne and Colman, 2006).…”

“…Glutathione S-transferases (GSTs; EC 2.5.1.18) belong to an almost universal superfamily of enzymes that is present and has evolved in all aerobic organisms (Hayes and Pulford, 1995;Regoli et al, 1997;Sheehan et al, 2001). The GSTs are involved in both the transport and biosynthesis of endogenous compounds and cellular defense mechanisms against xenobiotics and oxidative damage by catalyzing the conjugation of reduced glutathione through its cysteine thiol (Regoli et al, 1997;Sheehan et al, 2001).…”