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Search Results: 1 - 10 of 194512 matches for " Frédéric Marion-Poll "
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Hedonic Taste in Drosophila Revealed by Olfactory Receptors Expressed in Taste Neurons
Makoto Hiroi, Teiichi Tanimura, Frédéric Marion-Poll
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0002610
Abstract: Taste and olfaction are each tuned to a unique set of chemicals in the outside world, and their corresponding sensory spaces are mapped in different areas in the brain. This dichotomy matches categories of receptors detecting molecules either in the gaseous or in the liquid phase in terrestrial animals. However, in Drosophila olfactory and gustatory neurons express receptors which belong to the same family of 7-transmembrane domain proteins. Striking overlaps exist in their sequence structure and in their expression pattern, suggesting that there might be some functional commonalities between them. In this work, we tested the assumption that Drosophila olfactory receptor proteins are compatible with taste neurons by ectopically expressing an olfactory receptor (OR22a and OR83b) for which ligands are known. Using electrophysiological recordings, we show that the transformed taste neurons are excited by odor ligands as by their cognate tastants. The wiring of these neurons to the brain seems unchanged and no additional connections to the antennal lobe were detected. The odor ligands detected by the olfactory receptor acquire a new hedonic value, inducing appetitive or aversive behaviors depending on the categories of taste neurons in which they are expressed i.e. sugar- or bitter-sensing cells expressing either Gr5a or Gr66a receptors. Taste neurons expressing ectopic olfactory receptors can sense odors at close range either in the aerial phase or by contact, in a lipophilic phase. The responses of the transformed taste neurons to the odorant are similar to those obtained with tastants. The hedonic value attributed to tastants is directly linked to the taste neurons in which their receptors are expressed.
Frontiers in Invertebrate Physiology – Grand Challenge
Sylvia Anton,Christophe Gadenne,Frédéric Marion-Poll
Frontiers in Physiology , 2011, DOI: 10.3389/fphys.2011.00038
Electrophysiological and behavioral responses of Spodoptera littoralis caterpillars to attractive and repellent plant volatiles
Kacem Rharrabe,Emmanuelle Jacquin-Joly,Frédéric Marion-Poll
Frontiers in Ecology and Evolution , 2014, DOI: 10.3389/fevo.2014.00005
Abstract: In Lepidoptera, the behavior of caterpillars to plant odors is poorly known. However, caterpillars are equipped with a reduced number of olfactory sensilla (3 on the antenna and 4–5 on the maxillary palps) which they can use to make fine discrimination between complex plant odors. In this work, we characterized behavioral responses of Spodoptera littoralis larvae to 11 odorants found in plants using binary choices in a Petri dish assay. In this assay, 1-hexanol, hexanal and cis-jasmone elicited a dose-dependent attraction, camphene and eugenol were repellent, while the response to other odorants were less marked. We recorded the electrophysiological responses to 5 of these odors from olfactory neurons of sensillum B2 of the antenna. Several neurons from this sensillum responded to each of the chemicals tested by an increase of their firing activity on top of a high background activity, suggesting that olfactory neurons of caterpillars is broadly tuned to a range of odorants rather than being specialized to a few molecules.
Hygienic grooming is induced by contact chemicals in Drosophila melanogaster
Aya Yanagawa,Alexandra M. A. Guigue,Frédéric Marion-Poll
Frontiers in Behavioral Neuroscience , 2014, DOI: 10.3389/fnbeh.2014.00254
Abstract: In social insects, grooming is considered as a behavioral defense against pathogen and parasite infections since it contributes to remove microbes from their cuticle. However, stimuli which trigger this behavior are not well characterized yet. We examined if activating contact chemoreceptive sensilla could trigger grooming activities in Drosophila melanogaster. We monitored the grooming responses of decapitated flies to compounds known to activate the immune system, e.g., dead Escherichia coli (Ec) and lipopolysaccharides (LPS), and to tastants such as quinine, sucrose, and salt. LPS, quinine, and Ec were quite effective in triggering grooming movements when touching the distal border of the wings and the legs, while sucrose had no effect. Contact chemoreceptors are necessary and sufficient to elicit such responses, as grooming could not be elicited by LPS in poxn mutants deprived of external taste sensilla, and as grooming was elicited by light when a channel rhodopsin receptor was expressed in bitter-sensitive cells expressing Gr33a. Contact chemoreceptors distributed along the distal border of the wings respond to these tastants by an increased spiking activity, in response to quinine, Ec, LPS, sucrose, and KCl. These results demonstrate for the first time that bacterial compounds trigger grooming activities in D. melanogaster, and indicate that contact chemoreceptors located on the wings participate in the detection of such chemicals.
Peripheral, Central and Behavioral Responses to the Cuticular Pheromone Bouquet in Drosophila melanogaster Males
Tsuyoshi Inoshita,Jean-René Martin,Frédéric Marion-Poll,Jean-Fran?ois Ferveur
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0019770
Abstract: Pheromonal communication is crucial with regard to mate choice in many animals including insects. Drosophila melanogaster flies produce a pheromonal bouquet with many cuticular hydrocarbons some of which diverge between the sexes and differently affect male courtship behavior. Cuticular pheromones have a relatively high weight and are thought to be — mostly but not only — detected by gustatory contact. However, the response of the peripheral and central gustatory systems to these substances remains poorly explored. We measured the effect induced by pheromonal cuticular mixtures on (i) the electrophysiological response of peripheral gustatory receptor neurons, (ii) the calcium variation in brain centers receiving these gustatory inputs and (iii) the behavioral reaction induced in control males and in mutant desat1 males, which show abnormal pheromone production and perception. While male and female pheromones induced inhibitory-like effects on taste receptor neurons, the contact of male pheromones on male fore-tarsi elicits a long-lasting response of higher intensity in the dedicated gustatory brain center. We found that the behavior of control males was more strongly inhibited by male pheromones than by female pheromones, but this difference disappeared in anosmic males. Mutant desat1 males showed an increased sensitivity of their peripheral gustatory neurons to contact pheromones and a behavioral incapacity to discriminate sex pheromones. Together our data indicate that cuticular hydrocarbons induce long-lasting inhibitory effects on the relevant taste pathway which may interact with the olfactory pathway to modulate pheromonal perception.
Brief Exposure to Sensory Cues Elicits Stimulus-Nonspecific General Sensitization in an Insect
Sebastian Minoli, Isabella Kauer, Violaine Colson, Virginie Party, Michel Renou, Peter Anderson, Christophe Gadenne, Frédéric Marion-Poll, Sylvia Anton
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0034141
Abstract: The effect of repeated exposure to sensory stimuli, with or without reward is well known to induce stimulus-specific modifications of behaviour, described as different forms of learning. In recent studies we showed that a brief single pre-exposure to the female-produced sex pheromone or even a predator sound can increase the behavioural and central nervous responses to this pheromone in males of the noctuid moth Spodoptera littoralis. To investigate if this increase in sensitivity might be restricted to the pheromone system or is a form of general sensitization, we studied here if a brief pre-exposure to stimuli of different modalities can reciprocally change behavioural and physiological responses to olfactory and gustatory stimuli. Olfactory and gustatory pre-exposure and subsequent behavioural tests were carried out to reveal possible intra- and cross-modal effects. Attraction to pheromone, monitored with a locomotion compensator, increased after exposure to olfactory and gustatory stimuli. Behavioural responses to sucrose, investigated using the proboscis extension reflex, increased equally after pre-exposure to olfactory and gustatory cues. Pheromone-specific neurons in the brain and antennal gustatory neurons did, however, not change their sensitivity after sucrose exposure. The observed intra- and reciprocal cross-modal effects of pre-exposure may represent a new form of stimulus-nonspecific general sensitization originating from modifications at higher sensory processing levels.
Gαo Is Required for L-Canavanine Detection in Drosophila
Isabelle Devambez, Moutaz Ali Agha, Christian Mitri, Jo?l Bockaert, Marie-Laure Parmentier, Frédéric Marion-Poll, Yves Grau, Laurent Soustelle
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0063484
Abstract: Taste is an essential sense for the survival of most organisms. In insects, taste is particularly important as it allows to detect and avoid ingesting many plant toxins, such as L-canavanine. We previously showed that L-canavanine is toxic for Drosophila melanogaster and that flies are able to detect this toxin in the food. L-canavanine is a ligand of DmXR, a variant G-protein coupled receptor (GPCR) belonging to the metabotropic glutamate receptor subfamily that is expressed in bitter-sensitive taste neurons of Drosophila. To transduce the signal intracellularly, GPCR activate heterotrimeric G proteins constituted of α, β and γ subunits. The aim of this study was to identify which Gα protein was required for L-canavanine detection in Drosophila. By using a pharmacological approach, we first demonstrated that DmXR has the best coupling with Gαo protein subtype. Then, by using genetic, behavioral assays and electrophysiology, we found that Gαo47A is required in bitter-sensitive taste neurons for L-canavanine sensitivity. In conclusion, our study revealed that Gαo47A plays a crucial role in L-canavanine detection.
An Inhibitory Sex Pheromone Tastes Bitter for Drosophila Males
Fabien Lacaille, Makoto Hiroi, Robert Twele, Tsuyoshi Inoshita, Daisuke Umemoto, Gérard Manière, Frédéric Marion-Poll, Mamiko Ozaki, Wittko Francke, Matthew Cobb, Claude Everaerts, Teiichi Tanimura, Jean-Fran?ois Ferveur
PLOS ONE , 2007, DOI: 10.1371/journal.pone.0000661
Abstract: Sexual behavior requires animals to distinguish between the sexes and to respond appropriately to each of them. In Drosophila melanogaster, as in many insects, cuticular hydrocarbons are thought to be involved in sex recognition and in mating behavior, but there is no direct neuronal evidence of their pheromonal effect. Using behavioral and electrophysiological measures of responses to natural and synthetic compounds, we show that Z-7-tricosene, a Drosophila male cuticular hydrocarbon, acts as a sex pheromone and inhibits male-male courtship. These data provide the first direct demonstration that an insect cuticular hydrocarbon is detected as a sex pheromone. Intriguingly, we show that a particular type of gustatory neurons of the labial palps respond both to Z-7-tricosene and to bitter stimuli. Cross-adaptation between Z-7-tricosene and bitter stimuli further indicates that these two very different substances are processed by the same neural pathways. Furthermore, the two substances induced similar behavioral responses both in courtship and feeding tests. We conclude that the inhibitory pheromone tastes bitter to the fly.
ABA crosstalk with ethylene and nitric oxide in seed dormancy and germination
Fran?oise Corbineau,Lo?c Rajjou,Annie Marion-Poll
Frontiers in Plant Science , 2013, DOI: 10.3389/fpls.2013.00063
Abstract: Dormancy is an adaptive trait that enables seed germination to coincide with favorable environmental conditions. It has been clearly demonstrated that dormancy is induced by abscisic acid (ABA) during seed development on the mother plant. After seed dispersal, germination is preceded by a decline in ABA in imbibed seeds, which results from ABA catabolism through 8′-hydroxylation. The hormonal balance between ABA and gibberellins (GAs) has been shown to act as an integrator of environmental cues to maintain dormancy or activate germination. The interplay of ABA with other endogenous signals is however less documented. In numerous species, ethylene counteracts ABA signaling pathways and induces germination. In Brassicaceae seeds, ethylene prevents the inhibitory effects of ABA on endosperm cap weakening, thereby facilitating endosperm rupture and radicle emergence. Moreover, enhanced seed dormancy in Arabidopsis ethylene-insensitive mutants results from greater ABA sensitivity. Conversely, ABA limits ethylene action by down-regulating its biosynthesis. Nitric oxide (NO) has been proposed as a common actor in the ABA and ethylene crosstalk in seed. Indeed, convergent evidence indicates that NO is produced rapidly after seed imbibition and promotes germination by inducing the expression of the ABA 8′-hydroxylase gene, CYP707A2, and stimulating ethylene production. The role of NO and other nitrogen-containing compounds, such as nitrate, in seed dormancy breakage and germination stimulation has been reported in several species. This review will describe our current knowledge of ABA crosstalk with ethylene and NO, both volatile compounds that have been shown to counteract ABA action in seeds and to improve dormancy release and germination.
What Are the Ethical Problems Raised by the Increase of Cognitive Capabilities in the Defence Structure: The French Legal Structure, the Ethical Position of the French Military Health Service  [PDF]
Marion Trousselard, Frédéric Canini
Psychology (PSYCH) , 2015, DOI: 10.4236/psych.2015.64047
Abstract: All contemporary discussions concerning the ethics of human experimentation are grounded in the Nuremberg Code (Macklin, 1992) which listed what for many are the basic principles underlying the ethical conduct of human research. By law all scientific researches that use human research volunteers are governed by regulations prescribing the ethical treatment of these volunteers (Jones, 1993). The present purpose concerns what Ethics is in order to discuss about how military researches are directly affected by these regulations. They particularly concern neurosciences and precisely how to improve cognition for military individuals. Main arsenal was discussed according the risk-benefit balance. Furthermore, implications for medical reflexion were proposed. The French law prescribing the ethical principles for conducting research on humans as animals have been successively defined in accordance with European texts (French Public Health Code, 1994, 2004; Favre, Vallet, Renaudeau et al., 2004). All of these have consequences for conducting the French biomedical research for the defence.
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