Gonca Alak

Investigation of 8-OHdG, CYP1A, HSP70 and transcriptional analyses of antioxidant defence system in liver tissues of rainbow trout exposed to eprinomectin

&NA; 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 &mgr;g/L, 0.002 &mgr;g/L, 0.01 &mgr;g/L, 0.05 &mgr;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. HighlightsEPM has biochemical and physiological effects in fish liver.These parameters may be involved in the toxicity mechanism of EPM on rainbow trout.8‐OHdG, CYP1A, HSP70 and antioxidant parameters might be utilized as a potential indicator of exposure to antibiotic in fish.

Evaluation of 8-hydroxy-2-deoxyguanosine and NFkB activation, oxidative stress response, acetylcholinesterase activity, and histopathological changes in rainbow trout brain exposed to linuron

Linuron is a widely used herbicide to control grasses and annual broad leaf weeds. It is known that linuron has toxic effects on different organisms. However, the toxic effects of linuron on aquatic organisms, especially fish, is completely unknown. Thus, we aimed to investigate changes in 8-hydroxy-2-deoxyguanosine (8-OHdG) and nuclear factor kappa B (NFkB) activity, histopathological changes, antioxidant responses and acetylcholinesterase (AChE) activity in rainbow trout brain after exposure to linuron. Fish were exposed to 30μg/L, 120μg/L and 240μg/L concentrations of linuron for twenty-one days. Brain tissues were taken from fish for 8-OHdG and NFkB activity, histopathological examination and determination of superoxide dismutase (SOD), catalase (CAT) enzyme activity, lipid peroxidation (LPO), and reduced glutathione (GSH) levels. Our data indicated that high linuron concentrations caused a decrease in GSH levels, SOD and CAT activities in brain tissues (p<0.05). LPO levels were significantly increased by 240μg/L linuron. All concentrations caused a significant inhibition in brain AChE enzyme activity (p<0.05). Immunopositivity was detected for 8-OHdG and NFkB, and linuron exposure caused histopathological damage to the brain tissues. The results of this study can provide useful information for understanding of linuron-induced toxicity.

Assessment of 8-hydroxy-2-deoxyguanosine activity, gene expression and antioxidant enzyme activity on rainbow trout (Oncorhynchus mykiss) tissues exposed to biopesticide

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 0.00025ppm of DLM; 0.24 and 0.12ppm 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.

The determination of the swimming performance of rainbow trout (Oncorhynchus mykiss) under the effect of detergent

Detergent residues can lead to continuous damage in the cell membranes and make them become sensitive to the harmful effects of other toxic substances and infection factors. In this study, the behavioral responses of rainbow trout have been studied at the end of 21 days, where they have been exposed to different concentrations of Sodium Dodecyl Sulphate (SDS). In the fish which have been exposed to two different doses of SDS material, the swimming performance has been examined for behavior analysis with emphasis on critical swimming speed. The effect of SDS on critical swimming speed has been found to be significant (p <0.05).

Effects of iron chloride/zeolıte on G6PD of rainbow trout (Oncorhynchus mykiss)’s liver tissue

Aquatic ecosystems have been negatively affected by the contamination of ground and surface waters as a result of various activities. Due to the ferrous chloride (FeCl2), which is used as the reducing agent for the organic synthesis reactions in the contamination of water column and sediment, iron salts may be very toxic for some aquatic organisms. In order to minimize these effects, natural products such as zeolite have been widely used in recently years.For this reason, rainbow trout were exposed to FeCl2 and/or zeolite ((FeCl2 (0.002 mg/l)(A), FeCl2+zeolite (0.002 mg/l+1 gr/l) (B), zeolite (1 gr/l) (C) and control (without FeCl2 and/or zeolite (D)). for 28 days and their oxidative stress responses were investigated. At the end of the treatment period, Glucose-6- phosphate dehydrogenase (G6PD) activity was determined in the samples taken from livers. G6PD values for liver tissues were found statistically important in the control and treatment groups (p<0.01).

Investigation of humic acid effects versus cadmium toxicity on hematological paramaters of Brown Trout (Salmo trutta fario).

Bu calismada, kahverengi alabaliklarda (Salmo trutta fario Linneaus, 1792) kadmiyum toksisitesine karsi humik asitin koruyucu etkisi bazi hematolojik parametreler acisindan arastirilmistir. Baliklar kadmiyum ve/veya humik asite (2ppm Cd, 2ppm Cd+ 5 ppm humik asit ve kontrol) 7 gun boyunca maruz birakilmislardir. Deneme periyodu sonunda hematolojik parametrelerden hemoglobin, hematokrit, eritrosit, eritrosit basina dusen ortalama hemoglobin miktari (MCH), ortalama eritrosit hacmi (MCV) ve eritrosit basina dusen ortalama hemoglobin konsantrasyonu (MCHC) degerlerinde meydana gelen degisimler incelenmistir. Istatistiki acidan tum parametrelerde gruplar arasi fark belirlenmis olsa da kirmizi kan hucresi (RBC), hematokrit, trombosit sayisi, MCV ve MCH parametreleri p