Antioxidant enzymes as biomarkers of Cu and Pb exposure in the ground spiders Lycosa terrestris and Pardosa birmanica

Abstract

Heavy metal exposure promotes oxidative stress in terrestrial organisms, which they counteract via activation of antioxidant biomarkers. The present study investigated the effects of copper (Cu) and lead (Pb) on total antioxidant capacity (TAC) and antioxidant enzymes such as Catalase (CAT), Glutathione reductase (GR), Superoxide dismutase (SOD) and Glutathione peroxidase (GPX) in two spider species, namely Lycosa terrestris and Pardosa birmanica. The spiders were exposed to Cu and Pb separately (10 ppm) or in combination (10 ppm each) via different exposure routes (i.e. food and soil) for 10, 20 and 40 days. The results showed that metal accumulation and antioxidant biomarker responses in spiders were metal-and speciesspecific, and depended on the exposure route of the metals. The level of all antioxidant biomarkers increased significantly with increasing exposure time and metal load in the bodies of spiders via both uptake routes. The significant inhibition of TAC and enzyme activities was only observed in single Pb treatment through soil exposure. In L. terrestris, the activities of detoxification enzymes and TAC were significantly enhanced on single Cu exposure than Pb via both exposure routes. However, in P. birmanica consistent variation among antioxidant parameters were observed depending on the metal load and exposure routes. The combined metal exposure caused more pronounced increase in the level of antioxidants compared to single metal exposure in both species mainly via food exposure. These results suggest that the antioxidant enzymes and TAC are sensitive to single and combined metal exposure via both uptake routes. Furthermore, the antioxidant parameters can be used potential biomarkers of oxidative stress induced by metal exposure and for monitoring environmental health using spiders as bioindicators.

Ameliorative effect of the dietary Egyptian leek ( Allium ampeloprasum L. var. kurrat ) on zinc toxicity of the African catfish Clarias gariepinus (Burchell, 1822)

“…Regarding the total antioxidant capacity (TAC), it is used to measure the total antioxidant status of any organism that is exposed to xenobiotics. Accordingly, TAC indicates the efficiency of antioxidants to scavenge toxic radicals in any organism more than each antioxidant's separate measurement (Aziz et al, 2020; Franco et al, 2016). In other words, TAC represents a good tool to determine the collective defence strategies of an organism against oxidative stress and as an alternative to the standard antioxidant defences (Aziz et al, 2020; Cossi et al, 2018) and shows the capability of an organism to remove free radicals (Miller et al, 1993; Mirvaghefi et al, 2015).…”

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“…The growth of microorganisms in the presence of pollutants can lead to the generation of reactive oxygen species (ROS) that cause oxidative stress in cells. Excessive accumulation of ROS and its intermediates inside cells can cause oxidative stress in the body, such as oxidation of amino acid side chains that disrupt the structure and function of proteins, leading to inactivation of enzymes, damage to the cell membrane, damage to cell division and followed by cell death [38].…”

“…Exposure to heavy metals increases the production of ROS in the cells of microorganisms which in turn triggers their defense system to prevent oxidative damage [38]. The defense mechanisms against oxidative stress induced by free radicals involve: prevention mechanisms, recovery mechanisms and antioxidant defense.…”

Behavior of Plants and Microorganisms in the Presence of Inorganic Pollutants

“…The growth of microorganisms in the presence of pollutants can lead to the generation of reactive oxygen species (ROS) that cause oxidative stress in cells. Excessive accumulation of ROS and its intermediates inside cells can cause oxidative stress in the body, such as oxidation of amino acid side chains that disrupt the structure and function of proteins, leading to inactivation of enzymes, damage to the cell membrane, damage to cell division and followed by cell death [38].…”