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Öğe Comparative assessment of in vitro and in vivo toxicity of azinphos methyl and its commercial formulation(Wiley, 2015) Gungordu, Abbas; Uckun, MiracThe toxic effects of Gusathion (GUS), which is a commercial organophosphate (OP) pesticide, and also its active ingredient, azinphos methyl (AzM), are evaluated comparatively with in vitro and in vivo studies. Initially, the 96-h LC50 values of AzM and GUS were estimated for two different life stages of Xenopus laevis, embryos, and tadpoles. The actual AzM concentrations in exposure media were monitored by high-performance liquid chromatography. Also, the sub-lethal effects of these compounds to tadpoles were determined 24 h later at exposure concentrations of 0.1 and 1 mg/L using selected biomarker enzymes such as acetylcholinesterase (AChE), carboxylesterase (CaE), glutathione S-transferase (GST), glutathione reductase, lactate dehydrogenase, and aspartate aminotrasferase. Differences in AChE inhibition capacities of AzM and GUS were evaluated under in vitro conditions between frogs and fish in the second part of this study. The AChE activities in a pure electrical eel AChE solution and in brain homogenates of adult Cyprinus carpio, Pelophylax ridibundus, and X. laevis were assayed after in vitro exposure to 0.05, 0.5, 5, and 50 mg/L concentrations of AzM and GUS. According to in vivo studies AChE, CaE and GST are important biomarkers of the effect of OP exposure while CaE may be more effective in short-term, low-concentration exposures. The results of in vitro studies showed that amphibian brain AChEs were relatively more resistant to OP exposure than fish AChEs. The resistance may be the cause of the lower toxicity/lethality of OP compounds to amphibians than to fish. (c) 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 1091-1101, 2015.Öğe Equilibrium, kinetic, and thermodynamic studies on the biosorption of lead by human metallothionein gene-cloned bacteria as a novel biosorbent(Wiley, 2024) Akkurt, Seyma; Uckun, Aysel Alkan; Oguz, Merve; Uckun, Mirac; Kahraman, HuseyinHeavy metals are the main pollutants in water and are an important global problem that threatens human health and ecosystems. In recent years, there has been an increasing interest in the use of genetically modified bacteria as an eco-friendly method to solve heavy metal pollution problems. The goal of this study was to generate genetically modified Escherichia coli expressing human metallothioneins (hMT2A and hMT3) and to determine their tolerance, bioaccumulation, and biosorption capacity to lead (Pb2+). Recombinant MT2A and MT3 strains expressing MT were successfully generated. Minimum inhibition concentrations (MIC) of Pb for MT2A and MT3 were found to be 1750 and 2000 mg L-1, respectively. Pb2+ resistance and bioaccumulation capacity of MT3 were higher than MT2A. Therefore, only MT3 biosorbent was used in Pb2+ biosorption, and its efficiency was examined by performing experiments in a batch system. Pb2+ biosorption by MT3 was evaluated in terms of isotherms, kinetics, and thermodynamics. The results showed that Pb biosorption fits to the Langmuir isotherm model and the pseudo-first-order kinetic model, and the reaction is exothermic. The maximum Pb2+ capacity of the biosorbent was 50 mg Pb2+g-1. The potential of MT3 in Pb biosorption was characterized by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and scanning transmission electron microscopy (STEM) analyses. The desorption study showed that the sorbent had up to 74% recovery and could be effectively used four times. These findings imply that this biosorbent can be applied as a promising, precise, and effective means of removing Pb2+ from contaminated waters.Practitioner Points In this study, the tolerance levels, bioaccumulation, and biosorption capacities of Pb in aqueous solutions were determined for the first time in recombinant MT2A and MT3 strains in which human MT2A and MT3 genes were cloned. The biosorbent of MT3, which was determined to be more effective in Pb bioaccumulation, was synthesized and used in Pb biosorption. The Pb biosorption mechanism of MT3 biosorbent was identified using isotherm modeling, kinetic modeling, and thermodynamic studies. The maximum Pb removal percentage capacity of the biosorbent was 90%, whereas the maximum biosorption capacity was up to 50 mg Pb2+g-1. These results indicated that MT3 biosorbent has a higher Pb biosorption capacity than existing recombinant biosorbents. MT3 biosorbent can be used as a promising and effective biosorbent for removing Pb from wastewater. In this study, genetically modified bacteria were used to remove Pb+2 from water, which is an important global problem. To our knowledge, tolerance levels, bioaccumulation, and biosorption capacities of Pb+2 from aqueous solutions of MT2A and MT3 recombinant strains were determined for the first time in this study. MT3 biosorbent can be used as an effective tool for Pb+2 biosorption from water. imageÖğe Evaluating Multiple Biochemical Markers in Xenopus laevis Tadpoles Exposed to the Pesticides Thiacloprid and Trifloxystrobin in Single and Mixed Forms(Wiley, 2021) Uckun, Mirac; Ozmen, MuratPesticide exposure is thought to be one of the common reasons for the decline in amphibian populations, a phenomenon that is a major threat to global biodiversity. Although the single effects of pesticides on amphibians have been well studied, the effects of mixtures are not well known. The present study aimed to evaluate the acute toxicity of the insecticide thiacloprid and the fungicide trifloxystrobin on early developmental stages of Xenopus laevis using various biochemical markers (glutathione S-transferase, glutathione reductase, acetylcholinesterase, carboxylesterase, glutathione peroxidase, catalase, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, Na+K+-adenosine triphosphatase [ATPase], Ca2+-ATPase, Mg2+-ATPase, and total ATPase). The median lethal concentrations (LC50s) of thiacloprid and trifloxystrobin were determined to be 3.41 and 0.09 mg a.i. L-1, respectively. Tadpoles were exposed to the LC50, LC50/2, LC50/10, LC50/20, LC50/50, and LC50/100 of these pesticides. Both pesticides significantly affected (inhibited/activated) the biomarkers even at low concentrations. The pesticides showed a synergistic effect when applied as a mixture and altered the biomarkers more than when applied individually. In conclusion, we can assume that tadpoles are threatened by these pesticides even at environmentally relevant concentrations. Our findings provide important data to guide management of the ecotoxicological effects of these pesticides on nontarget amphibians. Environ Toxicol Chem 2021;00:1-15. (c) 2021 SETACÖğe Fabrication, characterization, and application of laccase-immobilized membranes for acetamiprid and diuron degradation(Elsevier, 2024) Ulu, Ahmet; Akkurt, Seyma; Birhanli, Emre; Uckun, Aysel Alkan; Uckun, Mirac; Yesilada, Ozfer; Ates, BurhanWater and wastewater pollution by acetamiprid and diuron is considered a serious environmental problem. In this study, chitosan (CHS), a naturally occurring bioadsorbent considered ecologically harmless to remove these micropollutants, was developed as a possible carrier to immobilize laccase (Lac) from Trametes trogii. Polyethylene glycol methyl ether (PEGME) was chosen for blending CHS, so a hybrid biocatalyst-based Lac/CHSPEGME membrane was prepared. The prepared CHS-PEGME and Lac/CHS-PEGME membranes were characterized by Fourier-transformed-infrared (FTIR) spectroscopy, scanning-electron-microscopy (SEM), and X-raydiffraction (XRD). Pesticide degradation tests with Lac/CHS-PEGME were performed at different contact times and initial concentrations. Acetamiprid degradation was most effective (84 %) at the 12th hour, at an initial concentration of 0.1 mg/L, while diuron degradation was most effective (65 %) at an initial concentration of 6 mg/L and a contact time of 16th hour. Under optimum conditions, the reusability of Lac/CHS-PEGME was found to be 8 cycles for acetamiprid and 5 cycles for diuron. From these results, it is understood that acetamiprid is degraded more quickly and effectively than diuron. Adsorption process data were well fitted to the Langmuir isotherm model and the pseudo-first-order kinetic model. These findings showed that using Lac/CHS-PEGME was a practical and environmentally friendly method for acetamiprid and diuron degradation.Öğe Immobilization of laccase isolated from Trametes trogii on chitosan-based membrane and its application in the biodegradation of atrazine and trifloxystrobin pesticides(Springer, 2025) Uckun, Aysel Alkan; Uckun, Mirac; Akkurt, Seyma; Birhanli, Emre; Bakar, Busra; Ulu, Ahmet; Yesilada, OzferRecently, focus has been placed on various enzyme immobilization applications as effective, eco-friendly, and low-cost methods for the degradation of pesticides in water. Laccases are very effective biocatalysts that are frequently used in environmental remediation applications. In this research, the use of a biocatalyst obtained by immobilizing laccase purified from Trametes trogii on chitosan-polyethylene glycol methyl ether (Lac/CH/MPEG) in the degradation of atrazine (ATR) and trifloxystrobin (TFS) pesticides in water was investigated. The degradation of these pesticides with this synthesized biocatalyst is the first in the literature. Therefore, primarily, the basic physicochemical parameters and mechanical properties of Lac/CH/MPEG prepared before and after immobilization were investigated. Structural analysis and morphological imaging of Lac/CH/MPEG before and after degradation of ATR and TFS were also performed. In the degradation tests, the initial concentrations at which optimum degradation rates were observed for ATR (72%) and TFS (85%) were 1 mg L-1 and 0.5 mg L-1, and the contact times were 24 h and 12 h, respectively. Additionally, the reuse cycles of Lac/CH/MPEG in ATR and TFS degradation were found to be 5 and 6, respectively. These findings showed that TFS was degraded faster and more effectively than ATR. Compared to several biocatalysts in the literature, ours was shown to degrade pesticides more quickly and efficiently. Considering all the findings, it can be concluded that this novel Lac/CH/MPEG biocatalysts is promising, can be applied, and can be successfully used as an alternative agent for quick and efficient degradation of ATR and TFS in water/wastewater.Öğe Integrated assessment of biochemical markers in premetamorphic tadpoles of three amphibian species exposed to glyphosate- and methidathion-based pesticides in single and combination forms(Pergamon-Elsevier Science Ltd, 2016) Gungordu, Abbas; Uckun, Mirac; Yologlu, ErtanIn this study, we evaluated the toxic effects of a glyphosate-based herbicide (GBH) and a methidathion-based insecticide (MBI), individually and in combination, on premetamorphic tadpoles of three anuran species: Pelophylax ridibundus, Xenopus laevis, and Bufotes viridis. Based on the determined 96-h LC50 values of each species, the effects of a series of sublethal concentrations of single pesticides and their mixtures after 96-h exposure and also the time-related effects of a high sublethal concentration of each pesticide were evaluated, with determination of changes in selected biomarkers: glutathione S-transferase (GST), glutathione reductase (GR), acetylcholinesterase (AChE), carboxylesterase (CaE), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH). Also, the integrated biomarker response (IBR) was used to assess biomarker responses and quantitatively evaluate toxicological effects. Isozyme differences in CaE inhibition were assessed using native page electrophoresis; results showed that GBH to cause structural changes in the enzyme but not CaE inhibition in P. ridibundus. In general, single MBI and pesticide mixture exposures increased GST activity, while single GBH exposures decreased GST activity in exposed tadpoles. The AChE and CaE activities were inhibited after exposure to all single MBI and pesticide mixtures. Also, higher IBR values and GST, GR, AST, and LDH activities were determined for pesticide mixtures compared with single-pesticide exposure. This situation may be indicative of a synergistic interaction between pesticides and a sign of a more stressful condition. (C) 2015 Elsevier Ltd. All rights reserved.Öğe Investigation of the effects of pinealectomy on acetylcholinesterase enzyme activity and oxidative stress in rat brain(Springer Japan Kk, 2025) Pekmez, Hidir; Ozkaya, Ahmet; Uckun, Mirac; Zayman, Emrah; Aydin, Merve; Canpolat, Sinan; Gul, MehmetThe pineal gland releases melatonin to regulate our body's circadian rhythm based on light and dark cycles. The pinealectomy (PINX) model is an experimental approach employed to investigate the potential impact of melatonin on various tissues and pathologies. In this study, acetylcholinesterase (AChE) enzyme activity levels, oxidative stress parameters, histopathological findings, and serum melatonin levels in rat brain tissue were evaluated following pinealectomy. 24 male Sprague Dawley rats were randomly divided into groups: control, Sham-Pinealectomy (SHAM), and PINX. Brain tissue samples were taken at the end of a 50-day experimental period to determine the parameters of AChE, glutathione s-transferase (GST), carboxylesterase (Ces) enzyme activities, and malondialdehyde (MDA), reduced glutathione (GSH) levels spectrophotometrically. Moreover, serum melatonin levels were measured, and tissues underwent standard histological analysis to determine the histopathological damage score. In this study, we found that the PINX group had decreased AChE and Ces enzyme activity, increased MDA, decreased GSH levels, and no change in GST enzyme activity. A relative decrease in serum melatonin levels was also observed in the PINX group. In the light microscopic examination of the brain tissue of pinealectomy rats, it was observed that the eosinophilic staining intensity increased, heterochromatic/pycnotic-looking neuron nuclei were prominent in the cortex layers and hippocampus, and perineural edematous areas were abundant. Excessive perineuronal edema, cytoplasmic eosinophilia, and heterochromatic/pycnotic nuclei were found based on the histopathological damage score. After pinealectomy, we observed an increase in oxidative stress and a decrease in AChE levels in the brain.Öğe Pomegranate Juice Treatment Prevents Carbon Tetrachloride(CCl4)-induced Testicular Damage in Rats: A Biochemical and Histological Study(Univ Ljubljana Press, 2025) Kalkan, Omer Faruk; Turk, Ahmet; Citil, Cihan; Uckun, Mirac; Ozkaya, Ahmet; Yologlu, Ertan; Ozay, YusufWe investigated the side effects of carbon tetrachloride (CCl4) on testicular tissue and explored the protective effects of pomegranate juice (PJ) against CCl4 exposure. Twenty-eight male Wistar albino rats were randomly divided into four groups as follows: Control, PJ, CCl4, and CCl4+PJ. We assessed serum testosterone levels and evaluated carboxylesterase (CaE), malondialdehyde (MDA), glutathione (GSH), glutathione reductase (GR) and glutathione Stransferase (GST) parameters. Histopathological changes were examined using CD68 immunoreactivity to detect macrophage activity. Analysis revealed a significant increase in CaE activity in the PJ group that compared to the control group (p < 0.05). CCl4 exposure reduced CaE activity, which was partially restored by PJ in the CCl4+PJ group (p < 0.05). PJ also significantly reduced the elevated MDA levels induced by CCl4 (p < 0.05). CCl4 alone decreased the reduced glutathione (GSH) levels (p < 0.05), however PJ had no effect on GSH levels (p > 0.05). Neither CCl4 nor PJ had an effect on glutathione reductase (GR) and glutathione S-transferase (GST) activity (p > 0.05). In conclusion, PJ reversed histological damage and restored reduced testosterone levels. Furthermore, it alleviated CCl4-induced oxidative stress by utilizing an alternative antioxidant system rather than glutathione.Öğe The protective effects of pomegranate juice on lead acetate-induced neurotoxicity in the male rat: A histomorphometric and biochemical study(Wiley, 2022) Annac, Ebru; Uckun, Mirac; Ozkaya, Ahmet; Yologlu, Ertan; Pekmez, Hidir; Bulmus, Ozgur; Aydin, AliThe purpose of this study was to investigate the potential side-effects of lead acetate (LA), which is toxic to the nerves, blood and muscles, in the rat brain. The neuroprotective effects of pomegranate juice (PJ) against LA exposure were also observed. The experiment involved 28 male Wistar albino rats aged 12 weeks. These were divided into four groups: Control, PJ, LA and LA+PJ. Stereological techniques were employed to determine hippocampal volume in each rat brain. Biochemical investigations and histopathological examinations were also performed. Analysis demonstrated a significant decrease in hippocampal volume in the LA group compared to the control group (p < .05). The stereology results also indicated that PJ has protective effects when compared with the LA and LA+PJ groups. A significant increase was also determined in malondialdehyde (MDA) levels and glutathione S-transferase (GST) activity in the LA group compared to the control group, in contrast to glutathione (GSH) levels and carboxylesterase (CaE) and acetylcholinesterase (AchE) activities. MDA and GST activity decreased significantly in the LA+PJ group compared to the LA group in contrast to GSH levels and CaE and AchE activities. Histopathological examination revealed a number of degenerative changes in the LA group. Exposure to LA adversely affects the hippocampus on the male rat brain. It might also be suggested that PJ may ameliorate these deleterious effects.
