In vitro effect of pesticides (dichlofluanid, endosulfan, simazine, tolylfluanid and triallate) on proliferative activity of animal derived cell cultures

Assessing the risk of booster biocides for the marine environment: A case study at the Belgian part of the North Sea

The biofouling of submerged surfaces such as ship hulls is often prevented by using anti-fouling components in combination with booster biocides. These booster biocides enter the water column and may affect non-target organisms. Although different negative effects have been associated with the use of booster biocides, their effects on non-target organisms are often unknown. So far, the environmental risks for booster biocides have barely been quantified in the North Sea. In this work, the concentration of five commonly used booster biocides as well as tributyltin has been monitored at five dredged spoil disposal sites in the Belgian part of the North Sea and the harbour and ports of Nieuwpoort, Oostende, and Zeebrugge. Hotspots were discovered where the concentration of one or more booster biocides exceeded the predicted no-effect concentration. Tributyltin has been banned since 2008, but concentrations of 237- to 546-fold of the predicted no-effect concentration were detected in the harbours and ports. Moreover, TBT has been detected in the same order of magnitude in other sea basins, emphasizing the need to monitor the trends and impact of booster biocides and TBT in environmental monitoring programs.

Investigation of the effects of some pesticides on carbonic anhydrase isoenzymes

The aim of this study was to investigate the inhibitory effects of some pesticides known to have harmful effects on human health on carbonic anhydrase isoenzymes. Therefore, carbonic anhydrase isoenzymes (hCA I and II) were purified from human erythrocytes. The isoenzymes were purified from human erythrocytes by using an affinity column that has the chemical structure of Sepharose-4B-4-(6-amino-hexyloxy)-benzenesulfonamide. The purity of the isoenzymes was checked by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDSPAGE). It was determined that the pesticides used in this study inhibit hCA I and hCA II isoenzymes at different levels in vitro. It was determined that the strongest inhibitor for the hCA I enzyme was Carbofuran (IC50 :6.52 μM; Ki : 3.58 μM) and the weakest one was 1-Naphtol (IC50 :16.55 μM; Ki : 14.4 μM) among these pesticides. It was also found that the strongest inhibitor for the hCA II enzyme was coumatetralil (IC50 :5.06 μM; Ki : 1.62 μM) and the weakest one was Dimethachlor (IC50 14.6 μM; Ki : 8.44 μM).

The mitochondrial pyruvate carrier at the crossroads of intermediary metabolism

Pyruvate metabolism, a central nexus of carbon homeostasis, is an evolutionarily conserved process and aberrant pyruvate metabolism is associated with and contributes to numerous human metabolic disorders including diabetes, cancer, and heart disease. As a product of glycolysis, pyruvate is primarily generated in the cytosol before being transported into the mitochondrion for further metabolism. Pyruvate entry into the mitochondrial matrix is a critical step for efficient generation of reducing equivalents and ATP and for the biosynthesis of glucose, fatty acids, and amino acids from pyruvate. However, for many years, the identity of the carrier protein(s) that transported pyruvate into the mitochondrial matrix remained a mystery. In 2012, the molecular-genetic identification of the mitochondrial pyruvate carrier (MPC), a heterodimeric complex composed of protein subunits MPC1 and MPC2, enabled studies that shed light on the many metabolic and physiological processes regulated by pyruvate metabolism. A better understanding of the mechanisms regulating pyruvate transport and the processes affected by pyruvate metabolism may enable novel therapeutics to modulate mitochondrial pyruvate flux to treat a variety of disorders. Herein, we review our current knowledge of the MPC, discuss recent advances in the understanding of mitochondrial pyruvate metabolism in various tissue and cell types, and address some of the outstanding questions relevant to this field.

Increase in intracellular Ca(2+) level by phenylsulfamide fungicides, tolylfluanid and dichlofluanid, in rat thymic lymphocytes

Tolylfluanid, a phenylsulfamide fungicide, is one of the many pesticides that are frequently detected in crops. Therefore, its health risk is a concern. Micromolar concentrations of tolylfluanid induce chromosomal aberrations and micronuclei in mammalian lymphocytes. The findings prompted us to study the cellular actions of tolylfluanid and another frequently detected pesticide, dichlofluanid, at submicromolar and micromolar concentrations. Of the cellular actions of chemicals, the action on cellular Ca(2+) homeostasis is important since Ca(2+) is involved in cell signaling and death. Consequently, in this study, the effects of phenylsulfamide fungicides were examined on rat thymocytes by using fluorescent probes in order to further characterize the cellular actions of phenylsulfamide fungicides. Both phenylsulfamide fungicides exhibited biphasic, early and late, increase in intracellular Ca(2+) levels. The early phase was dependent on intracellular Ca(2+) release and increased membrane Ca(2+) permeability. The late phase was owing to Ca(2+) influx via activation of store-operated Ca(2+) channels and the further increase of membrane ionic permeability. Voltage-dependent Ca(2+) channels were not involved. The increases in intracellular Ca(2+) levels by phenylsulfamide fungicides were observed at drug concentrations of 0.1 μM or more (up to 10 μM). Thus, it is plausible that micromolar concentrations of phenylsulfamide fungicides deregulate intracellular Ca(2+) homeostasis in rat thymocytes. Both phenylsulfamide fungicides at 10 μM promoted the transition from intact living cells to living cells with phosphatidylserine-exposed membranes. This was not the case for phenylsulfamide fungicides at 3 μM. The potency of tolylfluanid was similar to that of dichlofluanid. Although the information on residual concentrations of tolylfluanid and dichlofluanid is very limited, their residual concentrations do not reach micromolar levels. It is unlikely that humans will develop adverse effects on exposure to phenylsulfamide fungicides under present environmental conditions.

Induction of SCEs and DNA fragmentation in bovine peripheral lymphocytes by in vitro exposure to tolylfluanid-based fungicide

The potential for genotoxic and cytotoxic effects of tolylfluanid-based fungicide (50% active agent) was evaluated using sister chromatid exchange (SCE) and proliferation indices (PI) in cultured bovine peripheral lymphocytes. For the detection of possible genetic damage, DNA fragmentation assay was also applied. Bovine lymphocytes cultured for 72 h were treated with the fungicide at the final concentrations of 1.75, 3.5, 8.75, and 17.5 μg/mL for the last 24 and 48 h of culture without S9 metabolic activation, and during the last 2 h of culture with S9 metabolic activation. In the SCE assays no evidence for genotoxic activity of the fungicide was found in treatments of 24 h without and 2 h with S9. After the 24 h exposure to tolylfluanid, a weak decrease in the PI was observed. With the prolonged exposure time (48 h), dose dependence in the increase of SCE frequencies was observed. Moreover, after 48 h exposure slight fragmentation of DNA at the concentrations of 3.5 and 8.75 μg/mL was demonstrated. SCE quantification is the most widely used approach for the assessment of genotoxic/cytogenetic effects of chemical compounds. Positive results in the assay at 48 h exposure indicated a potential of the fungicide to increase frequency of chromosomal damage (replication injuries) that is the confirmation of early effect of exposure.

Effect of fungicide Euparen Multi (Tolylfluanid) on the induction of chromosomal aberations in cultivated bovine lymphocytes

The effect of the fungicide Euparen Multi (containing 50% tolylfluanid) was investigated on the induction of chromosomal aberrations (CA) in cultured bovine peripheral lymphocytes. Cultures from two healthy donors were treated with tolylfluanid-based fungicide at concentrations ranging from 1.7 to 17.5 μg/ml for the last 24 and 48 hours of cultivation. Conventional cytogenetic method (CA assay) with Giemsa staining as well as fluorescence in situ hybridization (FISH) with whole bovine chromosomes 1 and 5 painting probes were used in the experiment. In the CA assay, no clastogenic effect of the fungicide was found after Euparen Multi treatment for 24 hours. On the contrary, significant elevation in polyploidy induction was observed with dose-dependence in one of the donors. Using prolonged time of exposure to the fungicide (the last 48 h of the cultivation), a slight clastogenic effect was detected at the doses of 8.75 and 17.5 μg/ml (P < 0.05, P < 0.01, respectively) in donor 1 and at the dose of 8.75 μg/ml (P < 0.05) in donor 2. The highest doses tested caused reduction of the mitotic indices (MI) (P < 0.05, P < 0.01) in both donors as well as both treatment times. The evaluation of stable structural aberrations in lymphocytes by two-colour FISH (48 h exposure) using bovine chromosome painting probes revealed the presence of nonreciprocal translocations at two examined concentrations (3.5 μg/ml and 8.75 μg/ml).

Micronucleus frequency in sheep lymphocytes after in vitro exposure to fungicide tolylfluanid

The fungicide tolylfluanid (N -dichlorofluoromethylthio-N', N -dimethyl -N -p -tolylsulfamide), was investigated by cytokinesis-block micronucleus assay. Tolylfluanid at the lowest concentration (1 x 10(- 6)mol L(- 1))did not influence significantly the frequency of micronuclei in sheep lymphocyte cultures in comparison with control (32.33 +/- 3.51/1000 binucleated cells versus 30.33 +/- 2.82/1000 binucleated cells in dimethylsulfoxide (DMSO) control, P = 0.44). Higher tolylfluanid concentrations (1 x 10(- 4) and, 1 x 10(- 5) mol L(- 1)) resulted in a significant dose-dependent increase in the number of micronuclei in comparison with control (74.00 +/- 13.00/1000 binucleated cells and 52.67 +/- 10.12/1000 binucleated cells versus 30.33 +/- 2. 82/1000 binucleated cells in DMSO control, P = 0.005 and 0.02, respectively, ANOVA followed by Tukey test P < 0.05). Many of the treated cells also possessed multiple micronuclei. Tolylfluanid did not affect the nuclear division index at all treatment concentrations. Our in vitro results thus demonstrate that tolylfluanid had a significant genotoxic effect at only the highest concentration tested.