Stéphane Reynaud

Stéphane Reynaud
University of Grenoble

Professor

About

115
Publications
11,471
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,819
Citations
Introduction
Impact of endocrine disruptors on aquatic animals Amphibian population decline
Additional affiliations
January 2006 - April 2021
Université Grenoble Alpes
Position
  • Professor
January 2005 - December 2010

Publications

Publications (115)
Article
Full-text available
The heavy use of pesticides in agricultural areas often leads to the contamination of nearby mosquito larvae breeding sites. Exposure to complex mixtures of agrochemicals can affect the insecticide sensitivity of mosquito larvae. Our study objective was to determine whether agrochemical residues in Anopheline larval breeding sites can affect the to...
Article
Animals must partition limited resources between their own growth and subsequent reproduction. Endocrine disruptors (ED) may cause maternal metabolic disorders that decrease successful reproduction and might be responsible for multi- and transgenerational effects in amphibians. We found that the frog Silurana (Xenopus) tropicalis, exposed to enviro...
Article
Full-text available
The introduction of neonicotinoids for managing insecticide resistance in mosquitoes is of high interest as they interact with a biochemical target not previously used in public health. In this concern, Bayer developed a combination of the neonicotinoid clothianidin and the pyrethroid deltamethrin (brand name Fludora Fusion) as a new vector control...
Article
A wide range of chemicals have been identified as endocrine disrupting chemicals (EDCs) in vertebrate species. Most studies of EDCs have focused on exposure of both male and female adults to these chemicals; however, there is clear evidence that EDCs have dramatic effects when mature or developing gametes are exposed, and consequently are associate...
Article
Endocrine disrupting chemicals (EDCs) are ubiquitous in the environment and involve diverse chemical-receptor interactions that can perturb hormone signaling. The Organization for Economic Co-operation and Development has validated several EDC-receptor bioassays to detect endocrine active chemicals and has established guidelines for regulatory test...
Preprint
Full-text available
Background: The introduction of neonicotinoids for managing insecticide resistance in mosquitoes is of high interest as they interact with a biochemical target not previously used in public health. In this concern, Bayer developed a combination of the neonicotinoid clothianidin and the pyrethroid deltamethrin (brand name Fludora Fusion) as a new ve...
Article
Resistance to chemical insecticides including pyrethroids, the main insecticide class used against mosquitoes, led to a regain of interest for neonicotinoids. In this context, the present study aims at characterizing the molecular basis of neonicotinoid resistance in the mosquito Aedes aegypti. Resistance mechanisms were studied by combining transc...
Article
Metabolic disorders induced by endocrine disruptors (ED) may contribute to amphibian population declines but no transgenerational studies have evaluated this hypothesis. Here we show that Xenopus tropicalis, exposed from the tadpole stage, to the ED benzo[a]pyrene (BaP, 50 ng.L⁻¹) produced F2 progeny with delayed metamorphosis and sexual maturity....
Article
Concern over global amphibian declines and possible links to agrochemical use has led to research on the endocrine disrupting actions of agrochemicals, such as fertilizers, fungicides, insecticides, acaricides, herbicides, metals, and mixtures. Amphibians, like other species, have to partition resources for body maintenance, growth, and reproductio...
Article
Full-text available
In addition to combating vector‐borne diseases, studying the adaptation of mosquitoes to insecticides provides a remarkable example of evolution‐in‐action driving the selection of complex phenotypes. Actually, most resistant mosquito populations show multi‐resistance phenotypes as a consequence of the variety of insecticides employed and of the com...
Article
Numerous studies suggest that amphibians are highly sensitive to endocrine disruptors (ED) but their precise role in population decline remains unknown. This study shows that frogs exposed to a mixture of ED throughout their life cycle, at environmentally relevant concentrations, developed an unexpected metabolic syndrome. Female Silurana (Xenopus)...
Preprint
Full-text available
In addition to combating vector-borne diseases, studying the adaptation of mosquitoes to insecticides provides a remarkable example of evolution-in-action driving the selection of complex phenotypes. Indeed, most resistant mosquito populations show multi-resistance phenotypes as a consequence of the variety of insecticides employed and of the compl...
Article
Full-text available
The anti-inflammatory ibuprofen is an ubiquitous surface water contaminant. However, chronic impact of this pharmaceutical on aquatic invertebrate populations remains poorly known. In the model insect Aedes aegypti, we investigated the intergenerational consequences of parental chronic exposure to an environmentally relevant concentration of ibupro...
Article
Despite numerous studies suggesting that amphibians are highly sensitive to endocrine disruptors (EDs), both their role in the decline of populations and the underlying mechanisms remain unclear. This study showed that frogs exposed throughout their life cycle to ED concentrations low enough to be considered safe for drinking water, developed a pre...
Article
Full-text available
Background The capacity of Aedes mosquitoes to resist chemical insecticides threatens the control of major arbovirus diseases worldwide. Until alternative control tools are widely deployed, monitoring insecticide resistance levels and identifying resistance mechanisms in field mosquito populations is crucial for implementing appropriate management...
Data
Detoxification genes targeted by DNA-seq analysis of upstream regions. (XLSX)
Data
Variations detected upstream of detoxification genes over-transcribed in resistant populations. (XLSX)
Data
Upstream variations associated with the over transcription of detoxification genes in resistant populations. (XLSX)
Data
Differential SNPs detected by RNA-seq. (XLSX)
Data
Detoxification genes showing a positive correlation between their expression level and CNV. Correlations were tested for each overexpressed detoxification gene by comparing Log2 CNV versus Log2 expression ratios. Correlations with Pearson’s r ≥ 0.7 and p ≤ 0.05 were considered significant. CNV data were extracted from [28]. (TIF)
Data
Promoter variations associated with the over-expression of detoxification genes in resistant populations. Only variations located within a 1 kb upstream of detoxification genes overexpressed in resistant populations were considered. Among them, variations showing a significant correlation (Pearson’s r ≥ 0.7 and p ≤ 0.05) between their allele freque...
Data
Transcription data of all differentially expressed genes. (XLSX)
Data
Correlation between allele frequencies estimated by RNA-seq and DNA-seq. Only SNPs affecting detoxification genes and detected by both approaches are shown. (TIF)
Article
Despite numerous studies suggesting that amphibians are highly sensitive to cumulative anthropogenic stresses, the role played by endocrine disruptors (EDs) in the decline of amphibian populations remains unclear. EDs have been extensively studied in adult amphibians for their capacity to disturb reproduction by interfering with the sexual hormone...
Article
Hazard assessment of chemical contaminants often relies on short term or partial life-cycle ecotoxicological tests, while the impact of low dose throughout the entire life cycle of species across multiple generations has been neglected. This study aimed at identifying the individual and population-level consequences of chronic water contamination b...
Article
Full-text available
The capacity of mosquitoes to resist insecticides threatens the control of diseases such as dengue and malaria. Until alternative control tools are implemented, characterizing resistance mechanisms is crucial for managing resistance in natural populations. Insecticide biodegradation by detoxification enzymes is a common resistance mechanism; howeve...
Article
Worldwide evolution of mosquito resistance to chemical insecticides represents a major challenge for public health, and the future of vector control largely relies on the development of biological insecticides that can be used in combination with chemicals (integrated management), with the expectation that populations already resistant to chemicals...
Article
Full-text available
Background: Despite the intensive use of Bacillus thuringiensis israelensis (Bti) toxins for mosquito control, little is known about the long term effect of exposure to this cocktail of toxins on target mosquito populations. In contrast to the many cases of resistance to Bacillus thuringiensis Cry toxins observed in other insects, there is no evid...
Article
Full-text available
Background Despite numerous studies suggesting that amphibians are highly sensitive to cumulative anthropogenic stresses, the role pollutants play in the decline of amphibian populations remains unclear. Amongst the most common aquatic contaminants, polycyclic aromatic hydrocarbons (PAHs) have been shown to induce several adverse effects on amphibi...
Article
Organochlorine pesticides (OCPs) are widespread environmental pollutants; two of them are highly persistent: lindane (γHCH) and chlordecone (CLD). Maize plants cope with high levels of OCP-environmental pollution, however little is known about cellular mechanisms involved in plant response to such OCP-exposures. This research was aimed at understan...
Article
Full-text available
Mosquito control programmes using chemical insecticides are increasingly threatened by the development of resistance. Such resistance can be the consequence of changes in proteins targeted by insecticides (target site mediated resistance), increased insecticide biodegradation (metabolic resistance), altered transport, sequestration or other mechani...
Article
Full-text available
The resistance of mosquitoes to chemical insecticides is threatening vector control programmes worldwide. Cytochrome P450 monooxygenases (CYPs) are known to play a major role in insecticide resistance allowing resistant insects to metabolize insecticides at a higher rate. Among them, members of the mosquito CYP6Z subfamily like Aedes aegypti CYP6Z8...
Article
Bacillus thuringiensis subsp. israelensis is a bioinsecticide increasingly used worldwide for mosquito control. Despite its apparent low level of persistence in the field due to the rapid loss of its insecticidal activity, an increasing number of studies suggested that the recycling of B. thuringiensis subsp. israelensis can occur under specific, u...
Poster
Full-text available
Fate of Bti in the field: from the unknown to the unexpected
Article
Mosquitoes are vectors of several major human diseases and their control is mainly based on the use of chemical insecticides. Resistance of mosquitoes to organochlorines, organophosphates, carbamates and pyrethroids led to a regain of interest for the use of neonicotinoid insecticides in vector control. The present study investigated the molecular...
Article
Bacillus thuringiensis subsp. israelensis is a bacterium producing crystals containing Cry and Cyt proteins, which are toxic for mosquito larvae. Nothing is known about the interaction between crystal toxins and decaying leaf litter, which is a major component of several mosquito breeding sites and represents an important food source. In the presen...
Article
Full-text available
Dengue is an important mosquito borne viral disease in Martinique Island (French West Indies). The viruses responsible for dengue are transmitted by Aedes aegypti, an indoor day-biting mosquito. The most effective proven method for disease prevention has been by vector control by various chemical or biological means. Unfortunately insecticide resis...
Article
The control of mosquitoes transmitting infectious diseases relies mainly on the use of chemical insecticides. However, the emergence of insecticide resistance threatens mosquito control programs. Until now, most research efforts have been focused on elucidating resistance mechanisms caused by insecticide treatments. Less attention has been paid to...
Article
A general consensus that an increased logK(ow) led to an increase in xenobiotic uptake and bioaccumulation is accepted. In this study we compared the toxicokinetics of two chemically different xenobiotics, i.e. benzo[a]pyrene and fipronil in female green frogs. Surprisingly, the uptake rates and the bioconcentration factors (BCF) of the two contami...
Article
Full-text available
Immunoglobulin (Ig) genes naturally acquire frequent premature termination codons during the error-prone V(D)J recombination process. Although B cell differentiation is linked to the expression of productive Ig alleles, the transcriptional status of nonfunctionally recombined alleles remains unclear. Here, we tracked transcription and posttranscrip...
Chapter
Full-text available
Background: The yellow fever mosquito Aedes aegypti is a major vector of dengue and hemorrhagic fevers, causing up to 100 million dengue infections every year. As there is still no medicine and efficient vaccine available, vector control largely based on insecticide treatments remains the only method to reduce dengue virus transmission. Unfortunate...
Article
The control of mosquitoes transmitting infectious diseases relies mainly on the use of chemical insecticides. However, resistance to most chemical insecticides threatens mosquito control programs. In this context, the spraying of toxins produced by the bacteria Bacillus thuringiensis subsp. israelensis (Bti) in larval habitats represents an alterna...
Patent
Method of extracting toxins Cry4Aa, Cry4Ba, Cry11Aa and Cyt1Aa of Bacillus thuringiensis var. israelensis from vegetable matter comprising the grinding of the vegetable matter, the addition of an extraction buffer, the sonication of the vegetable matter, the incubation of the vegetable matter and the recovery of the supernatant comprising the toxin...
Article
Aclonifen is a diphenylether herbicide in which one ring is unsubstituted and the other is NH2-1, Cl-2, NO2-6 substituted. This substitution, especially NH2-1, is a particular feature in the diphenylether herbicidal family. In contrast with other herbicides of the same family (acifluorfen, oxyfluorfen, bifenox) this compound is not only acting thro...
Preprint
Aclonifen is a diphenylether herbicide in which one ring is unsubstituted and the other is NH 2-1, Cl-2, NO 2-6 substituted. This substitution, especially NH 2-1, is a particular feature in the diphenylether herbi-cidal family. In contrast with other herbicides of the same family (acifluorfen, oxyfluorfen, bifenox) this compound is not only acting...
Article
Transcription profiles of 11 Aedes aegypti P450 genes from CYP6 and CYP9 subfamilies potentially involved in xenobiotic metabolism were investigated. Many genes were preferentially transcribed in tissues classically involved in xenobiotic metabolism including midgut and Malpighian tubules. Life-stage transcription profiling revealed important varia...
Data
Supplementary table 1. This table contains all transcription data for the 453 genes found differentially transcribed in Aedes aegypti larvae exposed to xenobiotics. Genes are arranged in nine different functional categories: enzymes; kinases; transport; DNA interaction; cuticle; cytoskeleton; ribosomes; others and unknown hypothetical proteins. For...
Data
Supplementary figure 1. This figure represents the distribution of the number of reads across distinct genes (6850 genes), clusters not mapped within predicted genes (4868 clusters), all mapped clusters (13118 clusters) and all mapped tags (15253 tags). Genes, clusters and tags are ranked in ascending order according to their total number of reads...
Data
Supplementary figure 2. This figure shows the validation of transcription ratios obtained from Digital Gene Expression Tag Profiling (DGETP) by real-time quantitative RT-PCR. Validation was performed on 14 genes found significantly over-transcribed by DGETP in at least one condition. For each gene, transcription ratios from both techniques across a...
Data
Supplementary figure 3. This figure represents the results of the principal component analysis of the effect of xenobiotics on mosquito larvae transcriptome. Analysis was based on log10 transcription ratios of all genes and clusters not mapped within genes showing a significant differential transcription in at least one treatment. Both xenobiotic t...
Data
Supplementary figure 4. This figure illustrates the preparation of the double stranded cDNA tag library. Messenger RNAs are isolated by using magnetic oligo(dT) beads before cDNA synthesis. Double stranded cDNAs are synthesized using DNA polymerase I and clived at every DpnII restriction sites. Gene expression (GEX) adapters 1 containing a MmeI rec...