Browsing by Author "Tas, Ismail Hakki"

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Assessment of 8-Hydroxy Activity, Gene Expression and Antioxidant Enzyme Activity on Rainbow Trout (Oncorhynchus Mykiss) Tissues Exposed To Biopesticide
(Elsevier Science inc, 2017) Alak, Gonca; Ucar, Arzu; Parlak, Veysel; Yeltekin, Ash Cilingir; Tas, Ismail Hakki; Olmez, Dogukan; Yanik, Telat
The goal of this study was to determinate toxicity mechanism of biopesticide with antioxidant enzymes parameters such as superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) and malondialdehyde (MDA) levels, oxidative DNA damage (8-hydroxy-2-deoxyguanosine (8-OHdG)), transcriptional changes of heat shock protein 70 (HSP70), and cytochromes P4501A (CYP1A), sod, cat, and gpx in liver and gill tissues of Oncorhynchus mykiss. For this aim, plant-based (natural pesticides, azadirachtin (AZA)) and synthetic pesticides (deltamethrin (DLM)) were exposed on the fish at different concentrations (0.0005 and 0.00025 ppm of DLM; 0.24 and 0.12 ppm of AZA) for 21 days. According to the results of the study, the activity of SOD, CAT and GPx decreased, but malondialdehyde (MDA) level and activity of 8-OHdG increased in the gill and liver of rainbow trout (p < 0.05). Additionally sod, cat and gpx were down regulated; HSP70 and CYP1A were up regulated for transcriptional observation. The downwards regulation of antioxidant (sod, cat and gpx) and the upregulation of HSP70 and CYP1A was obvious with doses of AZA or DLM (p < 0.05). The findings of this study suggest that biopesticide can cause biochemical and physiological effects in the fish gill and liver by causing enzyme inhibition, an increase in 8-OHdG levels and changes in both transcriptional parameters (sod, cat, gpx, HSP70 and CYP1A). We found that excessive doses of plant -based pesticide are nearly as toxic as chemical ones for aquatic organisms. Moreover, 8-OHdG, HSP70 and CYP1A used as a biomarker to determinate toxicity mechanism of biopesticide in aquatic environment.
Investigation of 8-Ohdg, Cyp1a, Hsp70 and Transcriptional Analyses of Antioxidant Defence System in Liver Tissues of Rainbow Trout Exposed To Eprinomectin
(Academic Press Ltd- Elsevier Science Ltd, 2017) Alak, Gonca; Yeltekin, Ash Cilingir; Tas, Ismail Hakki; Ucar, Arzu; Parlak, Veysel; Topal, Ahmet; Atamanalp, Muhammed
Eprinomectin (EPM), a member of avermectin family, is a semi-synthetic antibiotic. It has been known that avermectin family enters the aquatic environments and adversely affects the aquatic organisms. Effects of EPM is fully unknown in aquatic organisms especially fish, thus the aim of the present study was to investigate transcriptional changes (sod, cat, gpx) and activities of some antioxidant enzymes (superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) and malondialdehyde (MDA) levels, oxidative DNA damage (8-hydroxy-2-deoxyguanosine (8-OHdG)) and transcriptional changes of heat shock protein 70 (HSP70), and cytochromes P4501A (CYP1A) in liver tissues of rainbow trout exposed to sublethal EPM concentration (0.001 mu g/L, 0.002 mu g/L, 0.01 mu gL, 0.05 mu g/L) for 24 h, 48 h, 72 h and 96 h. The decrease in antioxidant enzyme (SOD, CAT and GPx) activity, transcriptional changes (sod, cat, gpx, HSP70 and CYP1A genes) and increase in MDA level and activity of 8-OHdG in a dose-time-dependent manner in the liver of rainbow trout were observed. The down-regulated of antioxidant (sod, cat and gpx), HSP70 and CYP1A obviously, the severity of which increased with the concentration of EPM and exposure time. The results imply that EPM could induce oxidative damage to the liver tissue of rainbow trout. The information presented in this study is helpful to understand the mechanism of veterinary pharmaceuticals-induced oxidative stress in fishes. (C) 2017 Elsevier Ltd. All rights reserved.
Investigation of 8-Ohdg, Cyp1a, Hsp70 and Transcriptional Analyses of Antioxidant Defence System in Liver Tissues of Rainbow Trout Exposed To Eprinomectin (Vol 65, Pg 136, 2017)
(Academic Press Ltd- Elsevier Science Ltd, 2018) Alak, Gonca; Yeltekin, Asli Cilingir; Tas, Ismail Hakki; Ucar, Arzu; Parlak, Veysel; Topal, Ahmet; Atamanalp, Muhammed
Neuroprotective Effects of Dietary Borax in the Brain Tissue of Rainbow Trout (Oncorhynchus Mykiss) Exposed To Copper-Induced Toxicity
(Springer, 2018) Alak, Gonca; Ucar, Arzu; Yeltekin, Asli Cilingir; Comakli, Selim; Parlak, Veysel; Tas, Ismail Hakki; Turkez, Hasan
We aimed to investigate the modulating effects of dietary borax on the pathways in rainbow trout brain exposed to copper. For this aim, a comprehensive assessment was performed including biochemical (acetylcholinesterase (AChE), malondialdehyde (MDA), oxidative DNA damage (8-hydroxy-2-deoxyguanosine (8-OHdG), and caspase-3 levels) and transcriptional parameters (heat shock protein 70 (HSP70) and cytochromes P450 (CYP1A), glutathione peroxidase (gpx), superoxide dismutase (sod), and catalase (cat)) parameters and immunohistochemically staining of 8-OHdG. Special fish feed diets were prepared for the trial. These diets contained different concentrations of borax (1.25, 2.5, and 5mg/kg) and/or copper (500 and 1000mg/kg) at the period of pre- and co-treatment strategies for 21days. At the end of the treatment periods, brain tissue was sampled for each experimental group. As a result, the biochemical parameters were increased and AChE activity decreased in the copper and copper-combined groups in comparison with the control group and also with only borax applications (p<0.05). We observed an increase or decrease in particular biochemical parameters for the borax group in every application and we established that borax had protective effect against copper toxicity by decreasing and/or increasing the relevant biochemical parameters in brain tissue of fish. The biochemical results of borax and its combinations corresponded to the observations of gene expression data, which similarly concluded that HSP70 and CYP1A genes were strongly induced by copper (p<0.05). In addition, the expression levels of the sod, cat, and gpx genes in the fish brains exposed to borax and the borax combination groups were significantly higher than the only copper-treated groups. In conclusion, borax supplementation provided significant protection against copper-induced neurotoxicity in trout.