Tolga Çavaş

In vivo genotoxicity evaluation of atrazine and atrazine–based herbicide on fish Carassius auratus using the micronucleus test and the comet assay

Atrazine is a selective triazine herbicide used to control broadleaf and grassy weeds mainly in corn, sorghum, sugarcane, pineapple, and other crops, and in conifer reforestation planting fields. It has been showed that atrazine is one of the most frequently detected pesticides in agricultural streams and rivers, over the past two decades. Although the toxic properties of atrazine are well known, the data on the genotoxic effects of atrazine on aquatic organisms are rather scarce. Thus, in the present study we aimed to evaluate the genotoxic effects of atrazine and an atrazine-based herbicide (Gesaprim®) on a model fish species Carassius auratus L., 1758, (Pisces: Cyprinidae) using the micronucleus test and the comet assay in peripheral blood erythrocytes. Fish were exposed to 5, 10 and 15 μg/L atrazine and to its commercial formulation for 2, 4 and 6 days. Ethyl methane sulfonate (EMS) at a single dose of 5 mg/L was used as positive control. Our results revealed significant increases in the frequencies of micronuclei and DNA strand breaks in erythrocytes of C. auratus, following exposure to commercial formulation of atrazine and thus demonstrated the genotoxic potential of this pesticide on fish.

Radioprotection by two phenolic compounds: Chlorogenic and quinic acid, on X-ray induced DNA damage in human blood lymphocytes in vitro

The present study was designed to determine the radioprotective effect of two phytochemicals, namely, quinic acid and chlorogenic acid, against X-ray irradiation-induced genomic instability in non-tumorigenic human blood lymphocytes. The protective ability of two phenolic acids against radiation-induced DNA damage was assessed using the alkaline comet assay in human blood lymphocytes isolated from two healthy human donors. A Siemens Mevatron MD2 (Siemens AG, USA, 1994) linear accelerator was used for irradiation. The results of the alkaline comet assay revealed that quinic acid and chlorogenic acid decreased the DNA damage induced by X-ray irradiation and provided a significant radioprotective effect. Quinic acid decreased the presence of irradiation-induced DNA damage by 5.99-53.57% and chlorogenic acid by 4.49-48.15%, as determined by the alkaline comet assay. The results show that quinic acid and chlorogenic acid may act as radioprotective compounds. Future studies should focus on determining the mechanism by which these phenolic acids provide radioprotection.

Effects of fullerenol nanoparticles on acetamiprid induced cytoxicity and genotoxicity in cultured human lung fibroblasts

The aim of this study was to investigate the effects of water soluble fullerene (fullerenol) nanoparticles on the in vitro genotoxicity induced by the insecticide acetamiprid. Healthy human lung cells (IMR-90) were treated with fullerenol C60(OH)n (n: 18-22) alone and in combination with acetamiprid for 24h. The micronucleus test, comet assay and γ-H2AX foci formation assays were used as genotoxicity endpoints. Cytotoxicity was evaluated using the clonogenic assay. The maximum tested concentration of fullerenol (1.600 μg/ml) induced 77% survival where as the lowest concentration (25 μg/ml) was not cytotoxic where as acetamiprid was cytotoxic. Fullerenol did not induce genotoxicity at tested concentrations (50-1600 μg/L). On the other hand, acetamiprid (>50 μM) significantly induced formation of micronuclei, and double and single stranded DNA breaks in IMR-90 cells. For simultaneous exposure studies, two non-cytotoxic concentrations (50 and 200 μg/ml) of fullerenol and three cytotoxic concentrations of acetamiprid (100, 200 and 400 μM) were selected. As a result, we observed that co-exposure with fullerenol significantly reduced the cytotoxicity and genotoxicity of acetamiprid in IMR-90 cells. Our results indicated the protective effect of water soluble fullerene particles on herbicide induced genotoxicity.

Evaluation of in vitro cytotoxicity and genotoxicity of copper–zinc alloy nanoparticles in human lung epithelial cells

In the present study, in vitro cytotoxic and genotoxic effect of copper-zinc alloy nanoparticles (Cu-Zn ANPs) on human lung epithelial cells (BEAS-2B) were investigated. XTT test and clonogenic assay were used to determine cytotoxic effects. Cell death mode and intracellular reactive oxygen species formations were analyzed using M30, M65 and ROS Elisa assays. Genotoxic effects were evaluated using micronucleus, comet and γ-H2AX foci assays. Cu-Zn ANPs were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential measurements. Characterization of Cu-Zn ANPs showed an average size of 200nm and zeta potential of -22mV. TEM analyses further revealed the intracellular localization of Cu-Zn ANPs in cytoplasm within 24h. Analysis of micronucleus, comet and γ-H2AX foci counts showed that exposure to Cu-Zn ANPs significantly induced chromosomal damage as well as single and double stranded DNA damage in BEAS-2B cells. Our results further indicated that exposure to Cu-Zn ANPs significantly induced intracellular ROS formation. Evaluation of M30:M65 ratios suggested that cell death was predominantly due to necrosis.

Sublethal toxicity of esbiothrin relationship with total antioxidant status and in vivo genotoxicity assessment in fish (Cyprinus carpio L., 1758) using the micronucleus test and comet assay

Esbiothrin, synthetic pyrethroid with quick activity against insects, is widely used against household pests and in public health. Despite widespread use, data on ecotoxicity and genotoxic effects are extremely scarce. The aim of the present study is to evaluate the genotoxic potential of esbiothrin on a model fish species Cyprinus carpio L., 1758 (Pisces: Cyprinidae, koi) using the micronucleus test and comet assay in peripheral blood erythrocytes. Effects of two sublethal exposure concentrations on plasma total antioxidant status (TAS mmol/L), and Hct values were examined. On the basis of the 96 h LC50 data from U.S. EPA ecotox database (32 μg/L) two sublethal exposure concentrations (5 and 10 μg/L) were used together with ethyl methanesulfonate (EMS) (5 mg/L) as positive control. Five fish were used for each dose/duration group (24, 48, and 72 h) under controlled laboratory conditions. The fish showed behavioral changes at the higher dose. Plasma TAS (mmol/L) levels decreased in 24 h; an increase was observed slightly for 48 and obviously for 72 h in both exposure doses. Similarly, hematocrit (Hct) values differed between exposure duration but no significant differences in mean values were found between groups of the same exposure time. The general trend was a rise after 48 h, which decreased afterwards. Our results revealed significant increases in the frequencies of micronuclei and levels of DNA strand breaks and thus demonstrated the genotoxic potential of this pesticide on fish, a nontarget organism of the aquatic ecosystem. To our knowledge this is the first study to report observable genotoxic effects of esbiothrin on fish.

Binary and ternary new water soluble copper(II) complexes of l-tyrosine and substituted 1,10-phenanthrolines: Effect of substitution on DNA interactions and cytotoxicities ☆

Binary and ternary water soluble copper(II) complexes - [Cu(nphen)2(H2O)](NO3)2·H2O (1), [Cu(phen)2(H2O)](NO3)2 (2), [Cu(nphen)(l-tyr)(H2O)]NO3·2H2O (3), [Cu(phen)(tyr)(H2O)] NO3·2H2O (4) - and diquarternary salts of nphen and phen (nphen=5-nitro-1,10-phenanthroline, phen=1,10-phenanthroline and tyr=l-tyrosine) have been synthesized and characterized by CHN analysis, (1)H NMR, (13)C NMR and IR spectroscopy, thermal analysis and single crystal X-ray diffraction techniques. The CT-DNA binding properties of these compounds have been investigated by thermal denaturation measurements, absorption and emission spectroscopy. The supercoiled pUC19 plasmid DNA cleavage activity of these compounds has been explored by agarose gel electrophoresis. The cytotoxicity of these compounds against MCF-7, Caco-2, A549 cancer cells and BEAS-2B healthy cells was also studied by using XTT method. The complexes 1-4 exhibit significant high cytotoxicity with low IC50 values in compared with cisplatin. The effect of the substituents of phen and coordinated amino acid in the above complexes are presented and discussed.

Antioxidant enzyme activity and lipid peroxidation in liver and gill tissues of Nile tilapia (Oreochromis niloticus) following in vivo exposure to domoic acid.

Domoic acid (DA) is a neurotoxicant produced by Pseudo-nitzschia from diatomeae. Although the neurotoxic and genotoxic effects of DA have been well documented, the number of in vivo studies regarding the oxidative stress inducing effects of DA is quite limited. In this study, in vivo toxic effects of DA were investigated on fish Oreochromis niloticus (Fam: Cichlidae), using oxidative stress biomarkers. Fish were exposed to three different concentrations (1, 5 and 10 microg/g body weight) of DA via intraperitoneal injections and the tissues were sampled at 24, 48 and 72 h post-treatment. Changes in the level of lipid peroxidation, and activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GRd) were evaluated in liver and gill tissues. Our results revealed dose and time dependent increases in the oxidative stress parameters. It was also observed that the toxic effects were more pronounced in liver than in gill tissue.

Radio-protective effect of cinnamic acid, a phenolic phytochemical, on genomic instability induced by X-rays in human blood lymphocytes in vitro.

The present study was designed to determine the protective activity of cinnamic acid against induction by X-rays of genomic instability in normal human blood lymphocytes. This radio-protective activity was assessed by use of the cytokinesis-block micronucleus test and the alkaline comet assay, with human blood lymphocytes isolated from two healthy donors. A Siemens Mevatron MD2 (Siemens AG, USA, 1994) linear accelerator was used for the irradiation with 1 or 2 Gy. Treatment of the lymphocytes with cinnamic acid prior to irradiation reduced the number of micronuclei when compared with that in control samples. Treatment with cinnamic acid without irradiation did not increase the number of micronuclei and did not show a cytostatic effect in the lymphocytes. The results of the alkaline comet assay revealed that cinnamic acid reduces the DNA damage induced by X-rays, showing a significant radio-protective effect. Cinnamic acid decreased the frequency of irradiation-induced micronuclei by 16-55% and reduced DNA breakage by 17-50%, as determined by the alkaline comet assay. Cinnamic acid may thus act as a radio-protective compound, and future studies may focus on elucidating the mechanism by which cinnamic acid offers radioprotection.