COPPER EFFECT ON COMPONENTS OF THE ANTIOXIDANT SYSTEM OF THE DIGESTIVE GLAND IN THE FRESHWATER MUSSEL ANODONTA CYGNEA

Abstract

The effects of copper accumulation and its impact on the functioning of some components of the antioxidant system (AOS) – CAT, GST, GSH – in the digestive gland of the freshwater mussel Anodonta cygnea were studied in an aquarium experiment. After a 12‑day acclimation, the mussels were divided among aquariums with Cu²⁺ concentrations of 0, 5, 50, 100, and 250 μg/L. Hepatopancreas tissue samples were taken for analysis after 1, 3, and 7 days. Copper ions content, GST and CAT activity, as well as GSH concentration were determined in the tissue. The accumulation process was shown to be doseand time-dependent. The metal accumulated in this concentration was not lethal. The rate of the metal accumulation in the studied organ increased along with the concentration of copper ions in the water. The activity of AOS enzymes in the swan mussel is modified as an adaptation in response to elevated copper concentrations to neutralize the products of oxidative reactions. Changes in the activity of AOS enzymes (CAT and GST) were observed mainly on the seventh day of the experiment at the highest copper concentrations tested. GST proved to be the most stable enzyme. The GSH level in the digestive gland changed 1 day after the start of the experiment, corroborating this tripeptide is involved in the first wave of protection against xenobiotics. Copper ions have a cumulative effect. The changes in enzyme activity observed on day 7 at Cu²⁺ concentration of 250 μg/L suggest that a longer exposure to copper, even in low concentrations, can be detrimental.