Investigation of antioxidant response in daphnia magna exposed to Bisphenol S

Bisfenol S (BPS), recently widely used, is a derivative of bisphenol. BPS is used as an alternative to bisphenol A (BPA) in many industrial products such as epoxy resins, thermal receipt papers, canned beverages, canned and ready-to-eat food containers, luggage tags, flyers, and newspaper materials because of its high heat stability and resistance to sunlight. Since bisphenol derivatives like BPS are not subject to as strict legal regulations as BPA, more data and information are needed for their controlled use. The widespread use of BPS leads to its extensive distribution in the environment and, consequently, high human exposure. There is very little information about the antioxidant defense system in aquatic organisms and their capacity to suppress oxidative stress caused by BPS. BPS can act as both a prooxidant and an antioxidant. In this study, it was investigated whether BPS exposure causes changes in the antioxidant enzymes Catalase (CAT) and Glutathione-S-transferase (GST) activities, as well as in the levels of malondialdehyde (MDA), an indicator of lipid peroxidation, in Daphnia magna exposed to BPS. For this purpose, D. magna samples that make up the live material were studied for 48 hours in environments containing different concentrations of pesticides. At the end of the study, while GST activity increased, there was no change in CAT activity and MDA levels in D. magna individuals exposed to low concentrations of BPS. In D. magna exposed to sublethal BPS concentrations for 48 hours, CAT activity remained unchanged, but it decreased at 50 mg/L where approximately 50% of these organisms died (48-h EC50 = 52.80 mg/L). Glutathione S-transferase activity significantly increased at 10 mg/L and continued to increase with increasing BPS dose. Lipid peroxidation levels of organisms exposed to BPS did not differ from those of control individuals. There was a significant increase in protein content at the highest exposure concentration, indicating an increase in protein synthesis. It has been determined that enzyme activities vary depending on different concentrations. Changes in CAT and GST enzymes and MDA levels in D. magna tissues in response to BPS demonstrate that these parameters can be used as useful biomarkers in such studies.