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Öğe Assessing the impact of antiviral drugs commonly utilized during the COVID-19 pandemic on the embryonic development of Xenopus laevis(Elsevier, 2024) Lacin, Cemal; Turhan, Duygu Ozhan; Gungordu, AbbasThe antiviral drugs favipiravir and oseltamivir are widely used to treat viral infections, including coronavirus 2019 (COVID-19), and their levels are expected to increase in the aquatic environment. In this study, the potential toxic and teratogenic effects of these drugs were evaluated using the frog embryo teratogenesis assay Xenopus (FETAX). In addition, glutathione S-transferase (GST), glutathione reductase (GR), catalase, carboxylesterase (CaE), and acetylcholinesterase (AChE) enzyme activities and malondialdehyde levels were measured as biochemical markers in embryos and tadpoles for comparative assessment of the sublethal effects of the test compounds. Prior to embryo exposure, drug concentrations in the exposure medium were measured with high-performance liquid chromatography. The 96-h median lethal concentration (LC50) was 137.9 and 32.3 mg/L for favipiravir and oseltamivir, respectively. The teratogenic index for favipiravir was 4.67. Both favipiravir and oseltamivir inhibited GR, CaE, and AChE activities in embryos, while favipiravir increased the GST and CaE activities in tadpoles. In conclusion, favipiravir, for which teratogenicity data are available in mammalian test organisms and human teratogenicity is controversial, inhibited Xenopus laevis embryo development and was teratogenic. In addition, sublethal concentrations of both drugs altered the biochemical responses in embryos and tadpoles, with differences between the developmental stages.Öğe ASSESSMENT OF EMBRYOTOXIC EFFECTS OF CADMIUM, LEAD AND COPPER ON Xenopus laevis(Parlar Scientific Publications (P S P), 2010) Gungordu, Abbas; Birhanli, Ayse; Ozmen, MuratThis work evaluated the effects of selected metals on embryos using Frog Embryo Teratogenesis Assay- Xenopus (FETAX). Besides FETAX parameters, changes in several biomarkers were studied as early signs of intoxication on Xenopus laevis tadpoles. The acute effects of metals were investigated by using the activity of the enzymes glutathione S-transferase (GST), glutathione reductase, acetylcholinesterase (AChE), carboxylesterase, lactate dehydrogenase, aspartate aminotranferase, and alanine aminotranferase. In the FETAX test, 96-h LC50s were determined as 1.6 mg/L, 96.1 mg/L, and 1.37 mg/L for Cd, Pb, and Cu, respectively. Also, teratogenic index (TI) of each metal was estimated as 1.1, 1.22, and 0.52 for Cd, Pb, and Cu, respectively. The TI showed that tested metals were not teratogenic in X. laevis embryos according to ASTM values. The comparison of selected metals on selected enzyme activities was expected to give useful indications for the proper use of biochemical responses as biomarkers.Öğe Assessment of seasonal and sex-related variability of biomarkers in carp (Cyprinus carpio L.) from Karakaya Dam Lake, Turkey(Elsevier Science Bv, 2011) Gungordu, Abbas; Ozmen, MuratThis study examines seasonal changes in the activities of selected biomarkers in carp (Cyprinus carpi L.) from Karakaya Dam Lake and evaluates the influence of gender and environmental factors on those activities. Physicochemical characteristics of water were evaluated in the lakewater. Fish were sampled on seasonal basis, and liver ethoxyresorufin-O-deethylase (EROD), glutathione-S-transferase, glutathione reductase, plasma lactate dehydrogenase, aspartate and alanine aminotransferase, and brain acetylcholinesterase (AChE) activities were assayed. Plasma vitellogenin level and hepatosomatic index and condition factors were also determined. Strong seasonal variations were observed but there were no gender differences among selected markers. The highest vitellogenin level of male fish was detected as 606 ng/mL which represents the estrogenicity of water in the lake in September 2005. In addition, the seasonal changes of some biomarkers such as EROD and AChE showed that the lake may be at risk of pollution by some xenobiotics arising from agricultural and/or industrial activities. (C) 2011 Elsevier B.V. All rights reserved.Öğe Biochemical and developmental effects of thyroid and anti-thyroid drugs on different early life stages of Xenopus laevis(Elsevier, 2021) Boran, Filiz; Gungordu, AbbasThe effects of two drugs containing the synthetic thyroid hormone levothyroxine (LEV) and an anti-thyroid drug containing propylthiouracil (PTU) on the three early life stages of Xenopus laevis were evaluated with the Frog Embryo Teratogenesis Assay-Xenopus, Tadpole Toxicity Test, and Amphibian Metamorphosis Assay using biochemical and morphological markers. Tested drugs caused more effective growth retardation in stage 8 embryos than stage 46 tadpoles. Significant inhibition of biomarker enzymes has been identified in stage 46 tadpoles for both drugs. AMA test results showed that LEV-I caused progression in the developmental stage and an increase in thyroxine level in 7 days exposure and growth retardation in 21 days exposure in stage 51 tadpoles. On the other hand, increases in lactate dehydrogenase activity for both drugs in the AMA test may be due to impacted energy metabolism during sub-chronic exposure. These results also show that the sensitivity and responses of Xenopus laevis at different early developmental stages may be different when exposed to drugs.Öğe Biochemical response to exposure to six textile dyes in early developmental stages of Xenopus laevis(Springer Heidelberg, 2013) Gungordu, Abbas; Birhanli, Ayse; Ozmen, MuratThe present study was undertaken to determine the toxic effect of a lethal concentration of six different commercially used textile dyes on the 46th stage of Xenopus laevis tadpoles. The tadpoles were exposed to Astrazon Red FBL, Astrazon Blue FGRL, Remazol Red RR, Remazol Turquoise Blue G-A, Cibacron Red FN-3G, and Cibacron Blue FN-R for 168 h in static test conditions, and thus, 168-h median lethal concentrations (LC(50)s) of each dye were determined to be 0.35, 0.13, 112, 7, 359, and 15.8 mg/L, respectively. Also, to evaluate the sublethal effects of each dye, tadpoles were exposed to different concentrations of dyes (with respect to 168-h LC(50)s) for 24 h. The alteration of selected enzyme activities was tested. For this aim, glutathione S-transferase (GST), carboxylesterase, and lactate dehydrogenase (LDH) were assayed. After dye exposure, the GST induction or inhibition and LDH induction indicated some possible mechanisms of oxidative stress and deterioration in aerobic respiration processes induced by the tested dyes. Findings of the study suggest that selected biomarker enzymes are useful in understanding the toxic mechanisms of these dyes in X. laevis tadpoles as early warning indicators. Therefore, these selected biomarkers may evaluate the effect of environmental factors, such as textile dye effluents and other industrial pollutants, on amphibians in biomonitoring studies.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 Comparative evaluation of toxicological effects and recovery patterns in zebrafish (Danio rerio) after exposure to phosalone-based and cypermethrin-based pesticides(Academic Press Inc Elsevier Science, 2018) Korkmaz, Volkan; Gungordu, Abbas; Ozmen, MuratThis study evaluated the toxic effects and recovery patterns in zebrafish (Danio redo) after exposure to phosalone-based (PBP) and cypermethrin-based (CBP) pesticides. Initially, the 96 h LC50 values of the pesticides were calculated as being 5.35 mu g of active ingredient (AI) L-1 for CBP and 217 mu g AI L-1 for PBP based on measured concentrations. Accordingly, experimental groups were exposed to three sublethal concentrations of pesticides for 96 h, separately, and then zebrafish were transferred to pesticide-free conditions for 10 and 20 days recovery periods. Biochemical markers were assessed including carboxylesterase (CaE), acetylcholinesterase (AChE), glutathione S-transferase (GST), lactate dehydrogenase, glutathione peroxidase, catalase, alanine and aspartate aminotransferase (ALT, AST) activities after the exposure and recovery periods. Also, the pesticide concentrations in test water were quantified by high-performance liquid chromatography (HPLC) analysis. Our results showed that AChE and CaE activities were significantly inhibited and GST was induced by both pesticides after 96 h exposure. For PBP exposure, the decreases for GST induction and CaE inhibition showed a partial recovery in pesticide-free conditions. However, the decreases in AChE activity for CBP exposure and insufficient increases in same enzyme activity for PBP exposure after 20 days in pesticide-free conditions indicated that the projected recovery period was not enough to the recovery of AChE activities and for the improvement of fish health.Öğe Comparative toxicity of methidathion and glyphosate on early life stages of three amphibian species: Pelophylax ridibundus, Pseudepidalea viridis, and Xenopus laevis(Elsevier, 2013) Gungordu, AbbasThe assessments of pesticide toxicity on nontarget organisms have largely been focused on the determination of median lethal concentration (LC50) values using single/laboratory species. Although useful, these studies cannot describe the biochemical mechanisms of toxicity and also cannot explain the effects of pesticides on natural species. In this study, the toxic effects of glyphosate and methidathion were evaluated comparatively on early developmental stages of 3 anurans-2 natural (Pelophylax ridibundus, Pseudepidalea viridis) and 1 laboratory species (Xenopus laevis). The 96-h LC50 values for methidathion and glyphosate were determined as 25.7-19.6 mg active ingredient (AI)/L for P. viridis, 27.4-22.7 mg AI/L for P. ridibundus, and 15.3-5.05 mg AI/L for X. laevis tadpoles. Furthermore, as early signs of intoxication, glutathione S-transferase (GST), acetylcholinesterase (AChE), carboxylesterase (CaE), glutathione reductase, lactate dehydrogenase, and aspartate aminotrasferase were assayed in 4-day-old tadpoles after 96-h pesticide exposure. The GST induction after 3.2 mg AI/L methidathion exposure was determined to be 173%, 83%, and 38% of control, and the AChE inhibition for the same dose was determined to be 86%, 96%, and 30% of control for P. ridibundus, P. viridis, and X. laevis, respectively. Unlike the application of methidathion, all enzyme activities showed statistically significant increases on glyphosate exposure Compared to controls. However, these increases in enzyme activities were not shown to be parallel with the increase of concentration. The levels of increases of GST and AChE were determined to be 111% and 31% for P. ridibundus, 13% and 51% for P. viridis, and 15% and 36% for X. laevis after 3.2 mg AI/L glyphosate exposure, respectively. The findings of the study suggest that the most sensitive species to pesticide exposure is X laevis. The selected biomarker enzymes AChE, CaE, and GST are useful in understanding the toxic mechanisms of these pesticides in anuran tadpoles as early warning indicators. (C) 2013 Elsevier B.V. All rights reserved.Öğe Developmental and lethal effects of glyphosate and a glyphosate-based product on Xenopus laevis embryos and tadpoles(Springer, 2020) Turhan, Duygu Ozhan; Gungordu, Abbas; Ozmen, MuratEffects of pure glyphosate and a glyphosate-based product were evaluated comparatively using two embryonic development stages of Xenopus laevis as model system. When pure glyphosate was applied in pH adjusted media, lethal or developmental effects were not observed at concentrations up to 500 mg L-1. The 96 h LC50 values for the commercial herbicide, in contrast, were 32.1 and 35.1 mg active ingredient L-1 for embryos and tadpoles, respectively. Since pure glyphosate has no effect on the selected biomarkers, it is thought that developmental toxic effects caused by glyphosate-based products are increased mainly due to formulation additives.Öğe Developmental, toxicological effects and recovery patterns in Xenopus laevis after exposure to penconazole-based fungicide during the metamorphosis process(Pergamon-Elsevier Science Ltd, 2022) Turhan, Duygu Ozhan; Gungordu, AbbasFungicides are a group of chemicals causing pollution of freshwater ecosystems due to their widespread use in agriculture. However, their endocrine disrupting effects are less studied than herbicides and insecticides. The aim of this study was to evaluate the developmental and toxicological effects and recovery patterns of penconazolebased fungicide (PBF) during Xenopus laevis metamorphosis. For this purpose, firstly, the 96 h median lethal (LC50) and effective (EC50) concentrations and minimum concentration to inhibit growth (MCIG) values of PBF were estimated for X. laevis as 4.97, 3.55 and 2.31 mg/L respectively, using Frog Embryo Teratogenesis AssayXenopus (FETAX) on Nieuwkoop-Faber (NF) stage 8 embryos. FETAX results showed PBF formulation was slightly teratogenic with a 1.4 teratogenic index; most recorded malformations were gut, abdominal edema, and tail curvature. The Subacute Amphibian Metamorphosis Assay (AMA) was modified based on acute FETAX results, and used to evaluate toxic effects and recovery patterns of relatively low PBF concentrations on metamorphosis using morphological and biochemical markers. NF Stage 51 tadpoles were exposed to two separate groups of each concentration for seven days in the AMA. Secondly, tadpoles of one group of each concentration continued to be exposed to PBF for the next 7 and 14 days while the other group was kept in a pesticide-free environment (depuration/recovery). Various morphological and biochemical markers were measured homogenate samples of tadpoles from exposure and recovery groups. Continuous exposure to relatively low PBF concentrations caused oxidative stress, toxic, and endocrine disrupting effects in the AMA, leading us to conclude that it has negative effects on frog health and development during the recovery period when PBF exposure is terminated. The glutathione S-transferase, glutathione reductase, catalase, carboxylesterase, and acetylcholinesterase activities were higher than the control group transferred to pesticide-free media for 14 days after the 7 days exposure and indicate persistent PBF impact.Öğe Ecotoxicity of Nanomaterials in Aquatic Environment(Springer International Publishing Ag, 2020) Ozmen, Murat; Gungordu, Abbas; Geckil, Hikmet[Abstract Not Available]Öğe Ecotoxicological assessment of water pollution in Sariyar Dam Lake, Turkey(Academic Press Inc Elsevier Science, 2008) Ozmen, Murat; Ayas, Zafer; Gungordu, Abbas; Ekmekci, Guler F.; Yerli, SedatGiven the effects of environmental pollution and different biotic factors on some important biochemical markers, as enzymes, two fish species inhabiting the Sariyar Dam Lake, Turkey have been investigated. Ethoxyresorufin O-deethylase, glutathion S-transferase, lactate dehydrogenase, alkaline phosphatase, acid phosphatase, and alanine and aspartate amino transferase activities have been measured in liver samples of Cyprinus carpio and Capoeta tinca. Also, brain acetylcholinesterase and carboxylesterase activities have been measured for the same samples. Selected enzymes confirmed that Sariyar basin is polluted by urban wastes and agricultural and industrial activities for many years. Organochlorine (OC) pesticide residues, caused by intensive agricultural activities, have also been observed in water, sediment samples, and adipose tissues of carp. Monitored results showed that SDL was polluted by different kinds of OC compounds such as DDT and its derivatives which are accumulated in adipose tissues of carp. Highest accumulation was found for beta-BHC in carp. The changes of enzyme activities in this study may be related to environmental pollution, while enzyme activity variations could be attributed to variable pollutants and variable concentrations of these pollutants. The results highlighted the potential convenience of these biomarkers to be used as components of environmental monitoring program in risk assessment studies in SDL. Since a seasonal variation in selected enzyme activities was found, the possible implications of such variability in the use of these enzymes as environmental biomarkers are also discussed. Hepatic cytosolic EROD did not show any significance according to the pollution factors in the lake which may be attributed to relatively less contamination by organic compounds such as PAH products. (C) 2007 Elsevier Inc. All rights reserved.Öğe Effect of nanosized TiO2 particles on the development of Xenopus laevis embryos(TUBITAK SCIENTIFIC & TECHNICAL RESEARCH COUNCIL TURKEY,, 2014) Birhanli, Ayse; Emre, Fatma Bilge; Sayilkan, Funda; Gungordu, AbbasThis paper reports the toxic properties of nano-TiO2 on 2 different early life stages of Xenopus laevis. Synthesis of nano-TiO2 particles was carried out by the hydrothermal method. Characterization of nanoparticles was performed using spectral techniques including X-ray diffraction, scanning electron microscopy, and a particle-size analyzer. Embryos at the 8th stage and tadpoles at the 46th stage were exposed to 7 concentrations of nano-TiO2 in the range of 5 to 320 ppm. After 96 h of exposure, the mortality percentage of each exposure concentration was calculated and the activity of enzyme biomarkers acetylcholinesterase, carboxylesterase, glutathione S-transferase, glutathione reductase, lactate dehydrogenase, and aspartate aminotransferase were determined in living embryos and tadpoles. None of the tested concentrations of TiO2 caused statistically significant mortality or malformation (only for the embryo test) as compared to the control groups. Furthermore, we did not observe any significant changes in enzyme activities in tadpole samples from the 46th stage, although some minor changes not related to the concentrations were observed in embryos.Öğe Evaluation of in vitro and in vivo toxic effects of newly synthesized benzimidazole-based organophosphorus compounds(Academic Press Inc Elsevier Science, 2013) Gungordu, Abbas; Sireci, Nihat; Kucukbay, Hasan; Birhanli, Ayse; Ozmen, MuratThis paper reports the toxic properties of eight newly synthesized benzimidazole-based organophosphorus (OP) compounds in Xeno pus laevis in both in vivo and in vitro conditions. For both experiments, a commercial solution of azinphos methyl (AzM, Gusathion M WP25) was used as a reference compound. The 24-h median lethal concentrations (LC50) of all tested compounds were determined for 46th stage tadpoles in the range of 9.54-140.0 mu M. For evaluation of the lethality of the compounds, the activity of the enzyme biomarkers acetylcholinesterase (AChE), carboxylesterase, glutathione S-transferase (GST), glutathione peroxidase, glutathione reductase, lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase were determined in vivo in X. laevis tadpoles exposed to three concentrations (LC50, LC50/2, and LC50/4) of tested compounds. All exposure concentrations of AzM and seven of eight tested compounds caused CaE inhibition in in vivo conditions. Furthermore, the AChE inhibition capacity of tested compounds in commercial electric eel AChE and in X. laevis homogenates and also CaE inhibition capacity in only X. laevis homogenates were assayed for a 30-min in vitro exposure period. Eight OP compounds did not inhibit AChE activity more than 23 percent, but AzM exposure inhibited AChE activity by 26 percent for X. laevis homogenates and 97 percent for electric fish AChE in in vitro conditions. Also. CaE inhibition levels in X. laevis tadpole homogenates were 46 percent for AzM and between 8 percent and 33 percent for other compounds in in vitro conditions. (C) 2012 Elsevier Inc. All rights reserved.Öğe Evaluation of PAH Metabolites in Bile of Common Carp, Cyprinus carpio L. with Fixed Wavelength Fluorescence in a Field and Laboratory Study(Taylor & Francis Ltd, 2011) Gungordu, AbbasThe seasonal and inter-gender variability of polycyclic aromatic hydrocarbon (PAH) metabolites in the bile of common carp (Cyprinus carpio) was investigated with a field study in Karakaya Dam Lake (KDL) and a laboratory-conducted study with the fish samples of KDL and Sultansuyu Dam Lake (Turkey). The KDL has been polluted by urban, industrial, and agricultural activities for many years. A seasonal trend was seen in PAH metabolite levels with higher levels detected in May 2005 samples in KDL. Their levels in the bile of fish were not found to be related to sex which showed that gender is not a confounding factor on PAH uptake. The results showed significant decreases in bile metabolite levels in the KDL fish by approximately 75% versus increases in the SDL fish after acclimation at laboratory conditions. These results supported that PAH metabolites in bile were not stable and short-term differences in living conditions may lead to great differences in their levels. Moreover, these rapid changes in bile metabolites with acclimation may also indicate that dam lakes were not badly polluted with PAHs and the feeding status of fish should be taken into consideration when using bile metabolites as biomarkers.Öğe Evaluation of spatial and temporal changes in biomarker responses in the common carp (Cyprinus carpio L.) for biomonitoring the Meric Delta, Turkey(Elsevier, 2012) Gungordu, Abbas; Erkmen, Belda; Kolankaya, DurdaneThe aim of this study is to examine the activity of several biomarkers in carp, Cyprinus carpi L., to determine their response to xenobiotics, such as organochlorine pesticides (OCPs), in the Meric Delta. Fish were collected from contaminated sites and from areas regarded as relatively less contaminated in four sampling periods. Hepatic glutathione S-transferase (GST), carboxylesterase (CaE), lactate dehydrogenase, aspartate aminotransferase, and acid phosphatase activities were measured as biomarkers in the fish. For all fish, the condition factor and hepatosomatic index, were calculated to determine the condition of the fish. The results of this study indicated that the mean GST activity showed an increase in fish from the Meric-Ergene junction site and a decrease in Enez site with respect to fish from Meric site. Furthermore, the study shows that spatial and temporal changes of biomarkers such as GST and CaE might be useful for the assessment of environmental contamination in the Meric Delta. (C) 2012 Elsevier B.V. All rights reserved.Öğe Evaluation of the biochemical effects of an acetamiprid-based insecticide on a non-target species,Gambusia holbrooki(Wiley, 2020) Demirci, Ozlem; Gungordu, AbbasThe toxic effects of an acetamiprid-based insecticide (ABI) onGambusia holbrookiwere evaluated after 24 and 96-h exposure periods. The 24 and 96-h median lethal concentration (LC50) values of ABI were determined as 75.9 and 42.2 mg/L active ingredient (AI)/L, respectively. In addition, the activity of five biochemical marker enzymes, including glutathione S-transferase (GST), glutathione reductase (GR), carboxylesterase (CaE), lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) was measured after 24 and 96-h exposure to three different concentrations of the ABI to evaluate its sublethal effects. The acetamiprid concentrations in the exposure media were measured using liquid chromatography-tandem mass spectrometry. Our results showed that GST and LDH activities were increased and there were concentration-dependent changes in the integrated biomarker response (IBR) indexes after 24-h ABI exposure. However, the examined biomarkers were not useful for examining the effects of the ABI exposure for 96-h exposure periods, even at the highest concentration.Öğe Evaluation on reducing toxicity of fluoxastrobin with doped TiO2 nanoparticles(Tubitak Scientific & Technological Research Council Turkey, 2021) Gungordu, Abbas; Ozmen, Nesrin; Erdemoglu, Sema; Turhan, Duygu Ozhan; Asilturk, Meltem; Akgeyik, Emrah; Ozmen, MuratIn this study, toxic effects caused by the degradation of fluoxastrobin, which is a commonly used fungicide where newly synthesized manganese or sulfur-doped TiO2 nanoparticles exist were evaluated. The characterization study of nanoparticles was performed by scanning an electron microscopy (SEM), X-ray diffractometry, Brunau-Emmet-Teller analysis, X-ray fluorescence spectroscopy, and UV-Vis (ultraviolet-visible) reflectance spectra. Subsequently, the photocatalytic performance of nanoparticles, their toxicity, and the photocatalytic degradation products of fluoxastrobin with the same nanoparticles were tested during the two development stages of Xenopus laevis. The LC(50)s of fluoxastrobin were determined on test organisms, and a 5 mg L-1 fluoxastrobin was selected to evaluate the photocatalytic degradation capacity due to toxicity studies. The sublethal effects of the nanoparticles and the degradation product of fluoxastrobin were assessed with embryonic malformations and biochemical marker responses. Sulfur-doped TiO2 was found to be more effective compared to manganese-doped TiO2 for the degradation of fluoxastrobin, photocatalytically. On the other hand, even if the tested nanoparticles were not lethal, they caused effects such as growth retardation and changes in biochemical responses on organisms.Öğe Heavy metal pollution in sediments and mussels: assessment by using pollution indices and metallothionein levels(Springer, 2016) Okay, Oya S.; Ozmen, Murat; Gungordu, Abbas; Yilmaz, Atilla; Yakan, Sevil D.; Karacik, Burak; Tutak, BilgeIn the present work, the concentration of eight metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) was determined in the sediments and transplanted and native mussels (Mytilus galloprovincialis). The study was conducted in Turkish marinas, shipyards, and shipbreaking yards. The effect of metal pollution was evaluated by determining the levels of metallothionein (MT) in the mussels. The extent of contamination for each single metal was assessed by using the geoaccumulation index (I-geo) and enrichment factor (EF). Whereas, to evaluate the overall metal pollution and effect, the pollution load index (PLI), modified contamination degree (mC(d)), potential toxicity response index (RI), mean effects range median (ERM) quotient (m-ERM-Q), and mean PEL quotient (m-PEL-Q) were calculated. The influence of different background values on the calculations was discussed. The results indicated a significant metal pollution caused by Cu, Pb, and Zn especially in shipyard and shipbreaking sites. Higher concentrations of MT were observed in the ship/breaking yard samples after the transplantation.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.
