Laurent BoualitAgroscope · Plants and Plant Products
Responsible for the in-crop environmental risk assessment of PPPs with respect to non-target arthropods.
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October 2017 - March 2018
Neurotoxic pesticides are used worldwide to protect crops from insects, they are recognized to impact nontarget organisms that live in areas surrounded by treated crops. Many biochemical and cell-based solutions have been developed for testing insecticide neurotoxicity. Nevertheless, such solutions provide a partial assessment of the impact of neur...
Amphibia is the most threatened class among vertebrates, with more than 40% of the species threatened with extinction. Pollution is thought to alter amphibian population dynamics. With the growing interest in behavioral ecotoxicology, the neurotoxic organophosphate pesticides are of special concerns. Understanding how the exposure to neurotoxics le...
Understanding the mechanisms underlying population decline is a critical challenge for conservation biologists. Both deterministic (e.g. habitat loss, fragmentation, and Allee effect) andstochastic (i.e. demographic and environmental stochasticity) demographic processes are involved in population decline. Simultaneously, a decrease of population si...
The research topic presented in the poster is about assessing the quality of the habitat of a polluted river in the north-western region of Algeria exposed to intensive agricultural activities and wastewaters discharges. For this purpose, we studied the physiological and biological responses of the snails Lymnaea stagnalis used as a bioindicator.
In this poster, we present our work on the impact of dejellying eggs prior to test 5 concentrations of Chlorpyrifos pesticide on X. laevis during 192 hours post fertilization. Our results suggest that in the case of Chlorpyrifos, the removal of jellycoat could increase the sensitivity of individuals regarding their size.
Kin selection and dispersal play a critical role in the evolution of cooperative breeding systems. Limited dispersal increases relatedness in spatially structured populations (population viscosity), with the result that neighbours tend to be genealogical relatives. Yet the increase in neighbours’ fitness-related performance through altruistic inter...
Understanding the mechanisms underlying biological extinctions is a critical challenge for conservation biologists. Both deterministic (e.g. habitat loss, fragmentation) and stochastic (i.e. demographic stochasticity, Allee effect) demographic processes are involved in population decline. Simultaneously, a decrease of population size has far-reachi...
Dispersal is a central mechanism in ecology and evolution. Dispersal evolution is driven by a trade-off between costs and benefits, which is influenced by interindividual variability and local environmental conditions (context-dependent dispersal). Many studies have investigated how dispersal decisions may be influenced by environmental factors, in...
Kin selection and dispersal play a critical role in the evolution of cooperative breeding systems. Limited dispersal dramatically increases relatedness in spatially structured populations (population viscosity), with the result that neighbours tend to be genealogical relatives. Yet the increase in neighbour performance through altruistic interactio...
Dispersal is a central mechanism in ecology and evolution. Dispersal evolution is driven by a trade-off between costs and benefits, which is influenced by inter-individual variability and local environmental conditions (context-dependent dispersal). Many studies have investigated how dispersal decisions may be influenced by environmental factors, i...
Dispersal is a central component of life history evolution. An increasing number of studies suggest that spatiotemporally variable environments may promote the evolution of "dispersal syndromes," consisting of covariation patterns between dispersal and morphological, physiological, behavioral, and life history traits. At the interspecifc scale, the...
In the Northern Hemisphere, an increase in both the frequency and magnitude of violent flooding events has been reported due to climate change. According to life history theory, one might postulate that in ‘slow’ species: (i) environmental canalisation may act as a selective force that minimises to some extent adult survival variations caused by ca...
I am currently working with X. laevis and I would like to collect blood samples. This would happened right before euthanasia on anesthetized individuals. My aim is to measure testosterone level. Does anyone have any document/protocol to share ?
I'm looking for recent data on the use of fertilizers and pesticides in EU forestry. Would you know any EU website where I could find it ?
Amphibians eggs are surrounded of a jelly coat constituted by one to several layers depending on the considered species. The composition of these layers depends on the considered layer and species. The functions of this layers are multiple. Indeed, the jelly coat is for instance known to be involved in fertilization, to avoid polyspermy, to act as a sperm chemoattractant and to play an important role of barrier against UV, infection and contaminants. But, the role of barrier against contaminants is not so clear. Indeed, the complex structure of the jelly coat provides to it an affinity to specific molecules. Therefore, certains molecules are stopped by the layers while others penetrate to the embryos.
In spite of this, most protocole for testing effect of toxicants on amphibians suggest to dejelly the eggs before the exposure. From my point of view, this recommendation lead to a loss of ecological relevance and I'm wondering if dejellying should not be reconsidered.
How about you ? Is there something that I don't see ?
I plan to measure AChE esterase on amphibians and I read that Butyrylcholinesterase can interfere in the measurement.
If I measure the transformation of Acetylcholine iodide, what am I measuring? Acetylcholinesterase activity or both acetyl- and butyrylcholinesterase activities ? Should I measure AChE activity with a BChE inhibitor for stating that I'm measuring AChE?
For me, I should but I've read a lot of articles that don't mention any use of the inhibitors, so I'm a bit confused.
I'm currently doing a PhD in Switzerland. Swiss legislation on the euthanasia of laboratory animals just changed. Now, euthanasia of amphibian's larvae have to be done using liquid nitrogen. My problem is that I have then to measure molecular biomarkers and I don't know if it's possible after such a euthanasia method. Does anyone already tried it, maybe on fish?
I'm currently helping at writing a project on amphibians and the ethical commission is asking us how will we measure an emaciation of an individual according to our score-sheet. Weighing all individuals would be really time consuming and would probably stress them.
Does anybody faced this question ?
I'm wondering if someone already tried to adapt the OECD Fish Embryo Acute Toxicity Test (FET) to Xenopus laevis embryos. I'd like to test the impact of certain pesticides on X. laevis embryos development and I think it would be a good way to adapt the FET.