Browsing by Author "Yeltekin, A.C."

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Investigation of Oxidative Stress, Lipid Peroxidation and DNA Damage in the Muscle Tissue of Young Trout Treated With Arsenic
(Nuray ERKAN OZDEN, 2025) Yeltekin, A.C.
Arsenic, a metalloid and metal compound commonly found in the earth's crust, dissolves in underground waters and can cause toxic effects by spreading through industrial processes or the environment. In this study, the changes in levels of antioxidant enzymes and several parameters (GSHPx, CAT, MDA, SOD, and 8-OHdG) in the muscle tissue of juvenile trout (Oncorhynchus mykiss) after arsenic exposure were investigated, and the data obtained were analysed. In our study, juvenile trout were divided into three groups, and arsenic was administered at saturations of 25, 50, and 75 mg/L. 96 hours after application, the muscle tissue from young trout was removed and homogenised. The 8-OHdG content in the muscle tissue was determined using an ELISA kit. The levels of SOD, CAT, GSH-Px and MDA were determined using spectrophotometric methods. In young trout with arsenic accumulation in muscle tissue, DNA damage was observed, and the 8OHdG content increased accordingly. There was deterioration in the cell membrane structure and lipid peroxidation. When the muscle tissue of young trout treated with arsenic was examined, a significant decrease in the concentrations of CAT, GSH-Px and SOD was observed. It is assumed that this is due to oxidative stress caused by the accumulation of free radicals in the muscle tissue of the fish. These changes occurred after arsenic was applied. The presence of heavy metals in large quantities in the habitats of aquatic organisms negatively affects their life and developmental stages, and their presence in the food chain and use as food by other species can cause significant toxicity. © 2025 The Author(s).
Physiological Response of Thiamethoxam and Ulexite in Rainbow Trout: a Neural Network-Mediated Approach
(Elsevier Inc., 2024) Alak, G.; Ucar, A.; Yeltekin, A.C.; Ozgeris, F.B.; Turkez, H.; Günay, A.; Atamanalp, M.
Fish, which are in constant contact with water, serve as an important ecological indicator of aquatic environment health. Therefore, in this study, in the name of neural degeneration, thiamethoxam (TMX) insecticide in the cerebral tissue of Oncorhynchus mykiss; neurotoxic endpoints such as biomarkers of oxidative stress, DNA damage and the status of antioxidant enzymes have been identified. Antioxidant enzyme (CAT, SOD, GPx, GSH) activities were significantly inhibited by TMX administration, and MDA and MPO values increased as a result of the stimulation of ROS (p < 0.05). It was interpreted that ulexite (UX) added to the medium was effective in favor of antioxidants and tried to prevent MDA and MPO levels. It was determined that Nrf-2, one of the inflammation parameters, was inhibited as a result of TMX application, and the supplementation of UX to the medium created merits similar to the no treatment group. In the 48th and 96th hour analyses of cerebral tissue, it was determined that IL-6 and TNF-α values were induced in TMX applied groups and UX tried to inhibit this situation. It was commented that TMX induced DNA damage and apoptosis at 48th–96th h, whereas UX suppressed this situation. The results provide possible in vivo evidence that UX supplements can reduce TMX-mediated oxidative stress and brain damage in O. mykiss brain tissue. © 2023 Elsevier Inc.
The Responses of Cholinergic System in the Brain Tissue of Van Fish (Alburnus Tarichi) Exposed to Antifungal Tebuconazole Compound Toxicity
(Nuray ERKAN OZDEN, 2022) Yeltekin, A.C.
Today, fungicide toxicity is quite common in aquatic ecosystems, and this situation adversely affects marine organisms. For this reason, it is essential to determine the effects of fungicides on aquatic organisms and to try to prevent organisms from being exposed to these toxic chemicals. In this study, changes in cholinergic system enzymes and (malondialdehyde) MDA levels as a result of exposure to acute fungicide toxicity in Van fish (Alburnus tarichi, Güldenstädt 1814) were in-vestigated. Brain tissue was taken from Van fish exposed to 2.5 M Tebuconazole used in agriculture by sampling at 24, 48, 72, and 96 hours. Brain tissue acetylcholinesterase (AChE), butyryl-cholinesterase (BChE) activities, and MDA levels were measured in this context. In the study, AChE (0.965± 0.03, 0.575±0.01) and BChE (0.421±0.02, 0,291±0.01) activities decreased in Van fish brain tissue due to exposure to Tebuconazole, but MDA (0.099±0.01, 0.192±0.01) level in-creased (p < 0.05). © 2022 The Author(s).