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Saxena A.K.,CSIR - Central Electrochemical Research Institute | Devillers J.,CTIS | Bhunia S.S.,Global Institute of Pharmaceutical Education and Research | Bro E.,National Game and Wildlife Institute ONCFS
SAR and QSAR in Environmental Research | Year: 2015

The potential effects of pesticides and their metabolites on the endocrine system are of major concern to wildlife and human health. In this context, the azole pesticides have earned special attention due to their cytochrome P450 aromatase inhibition potential. Cytochrome P450 aromatase (CYP19) catalyses the conversion of androstenedione and testosterone into oestrone and oestradiol, respectively. Thus, aromatase modulates the oestrogenic balance essential not only for females, but also for male physiology, including gonadal function. Its inhibition affects reproductive organs, fertility and sexual behaviour in humans and wildlife species. Several studies have shown that azole pesticides are able to inhibit human and fish aromatases but the information on birds is lacking. Consequently, it appeared to be of interest to estimate the aromatase inhibition of azoles in three different avian species, namely Gallus gallus, Coturnix coturnix japonica and Taeniopygia guttata. In the absence of the crystal structure of the aromatase enzyme in these bird species, homology models for the individual avian species were constructed using the crystal structure of human aromatase (hAr) (pdb: 3EQM) that showed high sequence similarity for G. gallus (82.0%), T. guttata (81.9%) and C. japonica (81.2%). A homology model with Oncorhynchus mykiss (81.9%) was also designed for comparison purpose. The homology-modelled aromatase for each avian and fish species and crystal structure of human aromatase were selected for docking 46 structurally diverse azoles and related compounds. We showed that the docking behaviour of the chemicals on the different aromatases was broadly the same. We also demonstrated that there was an acceptable level of correlation between the binding score values and the available aromatase inhibition data. This means that the homology models derived on bird and fish species can be used to approximate the potential inhibitory effects of azoles on their aromatase. © 2015 The Author(s). Published by Taylor & Francis. Source


Millot F.,National Game and Wildlife Institute ONCFS | Berny P.,Lyon College | Decors A.,National Game and Wildlife Institute ONCFS | Bro E.,National Game and Wildlife Institute ONCFS
Ecotoxicology and Environmental Safety | Year: 2015

Direct lethal and sublethal effects of pesticides on farmland birds' populations are recurring questions and largely debated. In this context, we conducted an innovative study combining radiotelemetry, farmer surveys, residue analyses on carcasses and modelling to assess the unintentional effects of pesticides on terrestrial birds. We chose the grey partridge Perdix perdix as a case study because this typical bird of European cereal ecosystems is highly exposed to pesticides. In this paper we focused on acute and short-term impacts of pesticides on adult mortality during spring and summer in a one-substance approach (multiple exposure were not studied here) but for a large variety of active substances (a.s.) actually used in cultivated farmland of Northern France. The fate and the location of 529 partridges were monitored twice a day from early March to late August 2010 and 2011 on 12 sites (14,500. ha). Their daily potential exposure to 183 a.s. was determined by overlapping birds' habitat use and daily pesticide application data. Based on this procedure, we calculated mortality rates within 10 days following a potential exposure for 157 different a.s. 5 a.s. were associated with a "10-day mortality rate" higher than 10% but a single one (thiacloprid) is reported to be highly toxic to birds. We recorded 261 mortalities among which 94 carcasses were in suitable condition for residue analyses. We detected at least one a.s in 39.4% of carcasses. However, only 2 mortality cases were attributed to poisoning (carbofuran). Furthermore, modelling results showed that these lethal pesticide-related poisonings decreased the population growth rate by less than 1%.In conclusion, we did not point out important direct acute and short-term effects of pesticides currently used by farmers during the breeding season on the grey partridge. This is discussed with regards to the complexity of potential effects in operational conditions. © 2015 Elsevier Inc. Source


Devillers J.,CTIS | Bro E.,National Game and Wildlife Institute ONCFS | Millot F.,National Game and Wildlife Institute ONCFS
SAR and QSAR in Environmental Research | Year: 2015

Numerous manmade chemicals released into the environment can interfere with normal, hormonally regulated biological processes to adversely affect the development and reproductive functions of living species. Various in vivo and in vitro tests have been designed for detecting endocrine disruptors, but the number of chemicals to test is so high that to save time and money, (quantitative) structure–activity relationship ((Q)SAR) models are increasingly used as a surrogate for these laboratory assays. However, most of them focus only on a specific target (e.g. estrogenic or androgenic receptor) while, to be more efficient, endocrine disruption modelling should preferentially consider profiles of activities to better gauge this complex phenomenon. In this context, an attempt was made to evaluate the endocrine disruption profile of 220 structurally diverse pesticides using the Endocrine Disruptome simulation (EDS) tool, which simultaneously predicts the probability of binding of chemicals on 12 nuclear receptors. In a first step, the EDS web-based system was successfully applied to 16 pharmaceutical compounds known to target at least one of the studied receptors. About 13% of the studied pesticides were estimated to be potential disruptors of the endocrine system due to their high predicted affinity for at least one receptor. In contrast, about 55% of them were unlikely to be endocrine disruptors. The simulation results are discussed and some comments on the use of the EDS tool are made. © 2015, Taylor & Francis. Source


Bro E.,National Game and Wildlife Institute ONCFS | Millot F.,National Game and Wildlife Institute ONCFS | Decors A.,National Game and Wildlife Institute ONCFS
Science of the Total Environment | Year: 2015

Estimating exposure of wild birds to plant protection products is of key importance in the risk assessment process evaluating their harmful potential.In this paper, we propose an ecologically-relevant methodology to estimate potential exposure to active substances (ASs) of a farmland focal bird, the gray partridge Perdix perdix. It is based on bird habitat use of fields at the time of pesticide applications. It accounts for spatio-temporal heterogeneity at population and landscape scales.We identify and quantify the potential exposure to 179 ASs of 140 clutches during pre-laying, laying, and incubation phases, and of 75 coveys. The data come from a large scale field study combining radiotelemetry and a farmer survey. They were collected in 12 different representative sites.The proportion of clutches potentially exposed to a given chemical was ≥5% for 32 ASs; prothioconazole and epoxiconazole ranking first. 71% of clutches were potentially exposed to ≥1 AS and 67% to ≥2 ASs. Mixtures involved 2 to 22 ASs. They emerged from commercial formulations, tank mixtures, bird habitat use, and combinations. ASs were fungicides (53%), herbicides (25%), and insecticides (16%) used on a variety of crops in April-June, when ground-nesting birds are breeding. The European Food Safety Authority conclusions report a long-term first-tier toxicity-to-exposure ratio (TERlt) <5 for 11 out of 19 documented ASs, and higher-tier TERlt <5 for 5 out of 10 ASs. This suggests a potential risk for bird reproduction in farmlands.Globally 13% of coveys were potentially exposed to 18 ASs during the first month (1-4 coveys per AS).The use of our field data in future research and risk assessment is discussed. © 2015. Source


Bro E.,National Game and Wildlife Institute ONCFS | Millot F.,National Game and Wildlife Institute ONCFS | Decors A.,National Game and Wildlife Institute ONCFS
Environmental Science and Pollution Research | Year: 2016

The contamination of the eggs of farmland birds by currently used plant protection products (PPPs) is poorly documented despite a potential to adversely impact their breeding performance. In this context, 139 eggs of 52 grey partridge Perdix perdix clutches, collected on 12 intensively cultivated farmlands in France in 2010–2011, were analysed. Given the great diversity of PPPs applied on agricultural fields, we used exploratory GC/MS-MS and LC/MS-MS screenings measuring ca. 500 compounds. The limit of quantification was 0.01 mg/kg, a statutory reference. A total of 15 different compounds were detected in 24 clutches. Nine of them have been used by farmers to protect crops against fungi (difenoconazole, tebuconazole, cyproconazole, fenpropidin and prochloraz), insects (lambda-cyhalothrin and thiamethoxam/clothianidin) and weeds (bromoxynil and diflufenican). Some old PPPs were also detected (fipronil(+sulfone), HCH(α,β,δ isomers), diphenylamine, heptachlor(+epoxyde), DDT(Σisomers)), as well as PCBs(153, 180). Concentrations ranged between <0.01 and 0.05 mg/kg but reached 0.067 (thiamethoxam/clothianidin), 0.11 (heptachlor + epoxyde) and 0.34 (fenpropidin) mg/kg in some cases. These results testify an actual exposure of females and/or their eggs to PPPs in operational conditions, as well as to organochlorine pollutants or their residues, banned in France since several years if not several decades, that persistently contaminate the environment. Routes of exposure, probability to detect a contamination in the eggs, and effects on egg/embryo characteristics are discussed with regard to the scientific literature. © 2016 The Author(s) Source

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