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- MakaleYalnız künye2025Scopus SJRQ3Antioxidant Enzyme Responses to Lead Exposure in Daphnia magna
Sahilli, Yeliz Cakir
Abstract: Lead (Pb), a pervasive environmental contaminant, poses significant toxicological risks to freshwater ecosystems. Daphnia magna, a widely used model organism in aquatic toxicology, provides valuable insights into the sublethal effects of heavy metal exposure. This study investigated the effects of Pb exposure on antioxidant defense mechanisms in D. magna. Test organisms were exposed to aqueous Pb solutions at varying concentrations (0, 10, 20, 30 μg/L) for 96 h. The enzyme activities of glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD) were measured using enzyme-linked immunosorbent assay (ELISA). SOD activity did not differ significantly between the exposed and control groups. However, CAT activity showed a significant decrease in all Pb-exposed groups compared to controls. GPx activity exhibited a non-significant decrease. In conclusion, Pb exposure may induce oxidative stress by generating reactive oxygen species (ROS) and inhibiting the function of sulfhydryl-containing antioxidant enzymes. Changes in antioxidant enzyme activity may serve as early biomarkers in ecotoxicological assessments of Pb pollution in aquatic environments. It is suggested that future studies incorporate molecular-level endpoints and chronic exposure scenarios to better elucidate the long-term impacts of Pb on aquatic invertebrates.
- MakaleYalnız künye2011Scopus SJRQ3MALONDIALDEHYDE LEVELS AND GLUTATHIONE PEROXIDASE ACTIVITIES IN THE TISSUES OF FRESHWATER CRAYFISH (ASTACUS LEPTODACTYLUS ESCH 1823) IN CULTURE CONDITION
Kandemir, F. M.; Benzer, F.; Erisir, M.; Yildirim, N. C.
The objective of the study was to characterize the effects of sex on lipid peroxidation (as malondialdehyde, MDA), antioxidant defence system (as glutathione peroxidase, GSH-Px) in the hepatopancreas, gonad and muscle tissues of freshwater crayfish, Astacus leptodactylus, in culture condition. The crayfish used in the present study was provided from Keban Dam Lake population of A. leptodactylus. 34 males and 30 females crayfish in different size were hold in stock ponds (6 x 6 x 0.5 m). This study was carried out between June 18, 2004 and December 1, 2004 at the crayfish reproduction unit of Aquaculture Faculty of Firat University, Elazig, Turkey. Plastic pipes (20 cm in length and 7 cm in diameter) were provided as shelters for the crayfish. Crayfish were fed 2 % of their total wet weight daily with prepared ration. Crayfish were exposed to natural photoperiod. During the study, the mean water temperature, dissolved oxygen and mean pH were 4 degrees C, 6.28 +/- 0.32 mg L-1 and 7.82 +/- 0.17, respectively. MDA and GSH-Px levels according to sex and tissue-species were determined. MDA level in the hepatopancreas and gonad of females were higher than males, except muscle tissue (P<0.001). However, the GSH-Px activities in the hepatopancreas and gonad of males were higher than females, except muscle tissue (P<0.001). As a result, MDA and GSH-Px levels in the hepatopancreas, gonad and muscle tissues of freshwater crayfish, Astacus leptodactylus, in culture condition changed both tissues and sex.
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