Calculation of Lipophilicity of Organophosphate Pesticides Using Density Functional Theory

Higher lipophilicity facilitates the passage of a substance across lipid cell membranes, the blood–brain barrier and protein binding, and may also indicate its toxicity. We proposed eight methods for predicting the lipophilicity of the 22 most commonly used organophosphate pesticides. In this work, to determine the lipophilicity and thermodynamic parameters of the solvation of pesticides, we used methods of density functional theory with various basis sets, as well as modern Grimm methods. The prediction models were evaluated and compared against eight performance statistics, as well as time and RAM used in the calculation. The results show that the PBE-SVP method provided the best of the proposed predictive capabilities. In addition, this method consumes relatively less CPU and RAM resources. These methods make it possible to reliably predict the ability of pesticide molecules to penetrate cell membranes and have a negative effect on cells and the organism as a whole.

Determination of insecticide residues and their adverse effects on blood profile of occupationally exposed individuals

Insecticides, essential for crop protection measures, leave behind several toxic residues that can result in a series of human health disorders. Therefore, this study was planned for the determination of residues and adverse effects of insecticides in blood samples of sprayers, pesticide-industry workers and controls by using blood parameters of these individuals as biomarkers. Optimized analytical methods using GC-MS and HPLC for the simultaneous detection of 22 currently used insecticides were adopted. Eight of twenty-seven (22.22%) sprayers' blood samples were found positive for five different insecticides. Eleven of twenty-seven (40.74%) pesticide-industry workers were found positive for eight different insecticides. The blood samples of both the exposed groups, sprayers and industry workers had significantly (P < 0.001; Mann-Whitney U-tests) low hemoglobin-Hb concentrations (12.17 ± 2.13 and 12.22 ± 2.37 g/dl respectively) than the average value of the control group with 14.23 ± 2.37 g/dl. The erythrocyte sedimentation rates (ESRs) in sprayers and insecticide industry workers (28.78 ± 20.72 and 28.17 ± 25.14 mm/1st h respectively) were greater significantly (P < 0.001; Mann-Whitney U test) than the control blood samples (9.53 ± 3.34 mm/1st h). These results indicate that the exposed individuals have experienced significant hemotoxic effects during insecticide exposure. The study also predicts the risk to exposed individuals in developing countries like Pakistan and demands realization of safety measures to prevent such dangerous effects of pesticide exposures.

The protective effect of vitamin E against changes in fatty acid composition of phospholipid subclasses in gill tissue of Oreochromis niloticus exposed to deltamethrin

The effects of deltamethrin on the fatty acid composition of phospholipid subclasses (phosphatidylchlonine (PC), phosphatidylethanolamine (PE), phosphatidylinositole (PI) and phosphatidylserine (PS)) in gill tissue of Oreochromis niloticus (Perciformes: Cichlidae) and the possible protective effect of vitamin E against deltamethrin were determined by gas chromatography. The changes in the fatty acid profile were analysed after 14 d of exposure. Treatments included Group I (fed with basal diet only), Group II (fed with vitamin E-supplemented diet), Group III (fed with basal diet and exposed to deltamethrin) and Group IV (fed with vitamin E-supplemented diet and exposed to deltamethrin). The effects of deltamethrin on PI, PE and PS were valid for the total saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). The effect on PC was detected in total SFAs and total PUFAs. The vitamin E-supplemented diet did not show complete protective effect on fatty acid composition of the fish exposed to deltamethrin. However, the protective effect was observed in total SFAs, total MUFAs and total PUFAs in PC. In PI, protective effect was only recorded on total PUFAs. There was no protective effect in PS and PE. The results of the present study demonstrated that deltametrin exposure had harmful effects on cell membrane and treatment with vitamin E could only partially protect fish gills.

The protective role of vitamin E on the fatty acid composition of phospholipid structure in gill and liver tissues of Oreochromis niloticus exposed to deltamethrin

Deltamethrin is a commonly used pyrethroid pesticide. Vitamin E is a antioxidant that plays an important role in protecting cells against toxicity by inactivating free radicals generated following pesticides exposure. Therefore, in the present study, it was evaluated whether deltamethrin induced changes on the fatty acid composition of phospholipid in gill and liver tissues in Oreochromis niloticus and, the possible protective effect of vitamin E against deltamethrin was determined. Fish was fed with no pesticide+control diet, no pesticide+vitamin E-supplemented diet, 1.45 μg/l deltamethrin+control diet, 1.45 μg/l deltamethrin+vitamin E-supplemented diet for twenty days. Pesticide and diet quality made an impact on the fatty acid composition of phospholipid. In treatments of deltamethrin, group fed with control diet showed much greater damage in comparison with group fed with vitamin E supplemented diet. The results indicated that the deltamethrin led to an increase in the percentages of total SFAs (saturated fatty acids) and total MUFAs (monounsaturated fatty acids) and a decrease in total PUFAs (polyunsaturated fatty acids) in the gill tissues. However, coadministration of deltamethrin and vitamin E showed decrease in the percentages of saturated fatty acids and increase in the percentages of polyunsaturated fatty acids in the gill tissues. In group fed with control diet, deltamethrin led to a decrease in the percentage of SFAs and a increase in total MUFAs in the liver. Coadministration of deltamethrin and vitamin E showed increase in the percentages of polyunsaturated fatty acids in the liver tissues. These results have demonstrated that administration of vitamin E along with deltamethrin decreases the peroxidation of unsaturated fatty acids and thus protects the cell membranes.

Screening membrane interactions of pesticides by cells decorated with chromatic polymer nanopatches

Elucidating the factors contributing to the cell toxicity of pesticides and other environmentally sensitive small molecules is critical for evaluation of their health impacts and for understanding the biological processes that they affect. Disruption and permeation of the plasma membrane, which constitutes the critical interface between the cell and its environment, are recognized initiators of cytotoxicity. We present a new approach for predicting pesticide cytotoxicity through rapid screening of membrane interactions of pesticides using a recently developed live-cell chromatic sensor. The sensing platform comprises living mammalian cells labeled with polydiacetylene (PDA), a chromatic polymer that undergoes intense fluorescence transformations induced by structural perturbations of the membrane bilayer. Within a short time after the addition of membrane-interacting tested compounds to the labeled cells, the PDA patches emit high fluorescence, which can be monitored by conventional spectroscopy and microscopy apparatuses. The chromatic technology facilitates rapid evaluation of membrane activity of pesticide compounds and is capable of distinguishing between toxic effects associated with membrane interactions vs intracellular mechanisms.

Proapoptotic effects of lindane on mouse primordial germ cells

Lindane (gamma-HCH) was examined for its effect on primordial germ cell (PGC) development in the mouse embryo. We found that exposure by gavage of pregnant mice to 15 or 30 mg/kg/bw lindane during the period of PGC migration and gonad colonization (from 8.5 to 11.5 days post coitum, dpc) resulted in a significant reduction of the number of germ cells within 12.5 dpc testis and ovaries (a maximum of about 25 and 40%, respectively). Similarly, lindane caused a dose-dependent decrease of the PGC number in an in vitro culture model. Further experiments showed that in such model, lindane induced features of apoptotic cell death in PGCs such as increase in caspase-3 activity, poly-ADP-ribose polymerase cleavage, and terminal dUTP nick-end labeling (TUNEL) positivity. A marked increase of the number of PGCs positive for TUNEL staining was also observed in 12.5 dpc gonads of embryos from pregnant mice subjected one day before to acute lindane treatment (60 mg/kg/bw). Finally, we show that a brief incubation of isolated PGCs with 10(-5)M lindane resulted in a marked decrease of the basal and kit-ligand-induced phosphorylation level of the AKT kinase, known to be crucial for PGC survival. Taken together these results demonstrate that embryo exposure to lindane during early stages of gametogenesis can severely impair the number of germ cells in the fetal gonads; the compound appears to affect PGC survival through a direct proapoptotic action likely resulting from its adverse effect on AKT activity in such cells.