Les styles de représentation, leurs déterminants et effets comportemenaux : étude empirique des sénateurs français

Typologies of parliamentarians play a central role in the study of legislators and their behavior. Wepropose a narrow concept of styles of representation, focused on the expressed characteristics ofparliamentarians and taking into account the largest possible spectrum of representational activitiesincluding the local and the national arena of the mandate.This concept enables us to study empirically the links between styles of representations -in ourcase of French senators-, their determinants and behavioral effects and to overcome thedescriptiveness of many studies mobilizing typologies of parliamentarians.The analysis of five styles of representation of the French senators show, that these styles areanswers to the constraints and resources of the parliamentarians and that they affect the senators’behavior in a systematic manner.Les typologies de parlementaires occupent une place centrale dans les études parlementaires.Nous proposons une définition du concept de «style de représentation», centrée sur lescaractéristiques déclarées des parlementaires - permettant de traiter les caractéristiques des élusdans leur diversité en examinant le spectre le plus large possible d’activités représentatives - et desaisir la manière dont ces activités s’articulent entre le niveau local et le niveau national. Ceconcept nous permettra d’étudier empiriquement les liens entre les styles de représentation -dansnotre cas des sénateurs français-, leurs déterminants et leurs effets comportementaux et desurmonter ainsi le descriptivisme propre à beaucoup d'études mobilisant des types parlementaires.L'analyse de cinq styles de représentation des sénateurs français met en évidence que les stylesde représentation sont des réponses aux contraintes et ressources des parlementaires et qu’ilsaffectent de manière systématique le comportement des sénateurs

Simultaneous stimulation of GABA and beta adrenergic receptors stabilizes isotypes of activated adenylyl cyclase heterocomplex

BACKGROUND: We investigated how the synthesis of cAMP, stimulated by isoproterenol acting through β-adrenoreceptors and Gs, is strongly amplified by simultaneous incubation with baclofen. Baclofen is an agonist of δ-aminobutyric acid type B receptors [GABA(B)], known to inhibit adenylyl cyclase via Gi. Because these agents have opposite effects on cAMP levels, the unexpected increase in cAMP synthesis when they are applied simultaneously has been intensively investigated. From previous reports, it appears that cyclase type II contributes most significantly to this phenomenon. RESULTS: We found that simultaneous application of isoproterenol and baclofen specifically influences the association/dissociation of molecules involved in the induction and termination of cyclase activity. Beta/gamma from [GABA]B receptor-coupled Gi has a higher affinity for adenylyl cyclase isoform(s) when these isoforms are co-associated with Gs. Our data also suggest that, when beta/gamma and Gαs are associated with adenylyl cyclase isoform(s), beta/gamma from [GABA]B receptor-coupled Gi retards the GTPase activity of Gαs from adrenergic receptor. These reciprocal regulations of subunits of the adenylyl cyclase complex might be responsible for the drastic increase of cAMP synthesis in response to the simultaneous signals. CONCLUSIONS: Simultaneous signals arriving at a particular synapse converge on molecular detectors of coincidence and trigger specific biochemical events. We hypothesize that this phenomenon comes from the complex molecular architectures involved, including scaffolding proteins that make reciprocal interactions between associated molecules possible. The biochemistry of simultaneous signaling is addressed as a key to synaptic function

Exploratory behaviour in NO-dependent cyclase mutants of Drosophila shows defects in coincident neuronal signalling

<p>Abstract</p> <p>Background</p> <p><it>Drosophila </it>flies explore the environment very efficiently in order to colonize it. They explore collectively, not individually, so that when a few land on a food spot, they attract the others by signs. This behaviour leads to aggregation of individuals and optimizes the screening of mates and egg-laying on the most favourable food spots.</p> <p>Results</p> <p>Flies perform cycles of exploration/aggregation depending on the resources of the environment. This behavioural ecology constitutes an excellent model for analyzing simultaneous processing of neurosensory information. We reasoned that the decision of flies to land somewhere in order to achieve aggregation is based on simultaneous integration of signals (visual, olfactory, acoustic) during their flight. On the basis of what flies do in nature, we designed laboratory tests to analyze the phenomenon of neuronal coincidence. We screened many mutants of genes involved in neuronal metabolism and the synaptic machinery.</p> <p>Conclusion</p> <p>Mutants of NO-dependent cyclase show a specifically-marked behaviour phenotype, but on the other hand they are associated with moderate biochemical defects. We show that these mutants present errors in integrative and/or coincident processing of signals, which are not reducible to the functions of the peripheral sensory cells.</p

Continued Neurogenesis in Adult Drosophila as a Mechanism for Recruiting Environmental Cue-Dependent Variants

Background The skills used by winged insects to explore their environment are strongly dependent upon the integration of neurosensory information comprising visual, acoustic and olfactory signals. The neuronal architecture of the wing contains a vast array of different sensors which might convey information to the brain in order to guide the trajectories during flight. In Drosophila, the wing sensory cells are either chemoreceptors or mechanoreceptors and some of these sensors have as yet unknown functions. The axons of these two functionally distinct types of neurons are entangled, generating a single nerve. This simple and accessible coincidental signaling circuitry in Drosophila constitutes an excellent model system to investigate the developmental variability in relation to natural behavioral polymorphisms. Methodology/Principal Findings A fluorescent marker was generated in neurons at all stages of the Drosophila life cycle using a highly efficient and controlled genetic recombination system that can be induced in dividing precursor cells (MARCM system, flybase web site). It allows fluorescent signals in axons only when the neuroblasts and/or neuronal cell precursors like SOP (sensory organ precursors) undergo division during the precedent steps. We first show that a robust neurogenesis continues in the wing after the adults emerge from the pupae followed by an extensive axonal growth. Arguments are presented to suggest that this wing neurogenesis in the newborn adult flies was influenced by genetic determinants such as the frequency dependent for gene and by environmental cues such as population density. Conclusions We demonstrate that the neuronal architecture in the adult Drosophila wing is unfinished when the flies emerge from their pupae. This unexpected developmental step might be crucial for generating non-heritable variants and phenotypic plasticity. This might therefore constitute an advantage in an unstable ecological system and explain much regarding the ability of Drosophila to robustly adapt to their environment

Transcript levels of ten caste-related genes in adult diploid males of Melipona quadrifasciata (Hymenoptera, Apidae) - A comparison with haploid males, queens and workers

In Hymenoptera, homozygosity at the sex locus results in the production of diploid males. In social species, these pose a double burden by having low fitness and drawing resources normally spent for increasing the work force of a colony. Yet, diploid males are of academic interest as they can elucidate effects of ploidy (normal males are haploid, whereas the female castes, the queens and workers, are diploid) on morphology and life history. Herein we investigated expression levels of ten caste-related genes in the stingless bee Melipona quadrifasciata, comparing newly emerged and 5-day-old diploid males with haploid males, queens and workers. In diploid males, transcript levels for dunce and paramyosin were increased during the first five days of adult life, while those for diacylglycerol kinase and the transcriptional co-repressor groucho diminished. Two general trends were apparent, (i) gene expression patterns in diploid males were overall more similar to haploid ones and workers than to queens, and (ii) in queens and workers, more genes were up-regulated after emergence until day five, whereas in diploid and especially so in haploid males more genes were down-regulated. This difference between the sexes may be related to longevity, which is much longer in females than in males

Post-translational modifications and mass spectrometry detection

In this review, we provide a comprehensive bibliographic overview of the role of mass spectrometry and the recent technical developments in the detection of post-translational modifications (PTMs). We briefly describe the principles of mass spectrometry for detecting PTMs and the protein and peptide enrichment strategies for PTM analysis, including phosphorylation, acetylation and oxidation. This review presents a bibliographic overview of the scientific achievements and the recent technical development in the detection of PTMs is provided. In order to ascertain the state of the art in mass spectrometry and proteomics methodologies for the study of PTMs, we analyzed all the PTM data introduced in the Universal Protein Resource (UniProt) and the literature published in the last three years. The evolution of curated data in UniProt for proteins annotated as being post-translationally modified is also analyzed. Additionally, we have undertaken a careful analysis of the research articles published in the years 2010 to 2012 reporting the detection of PTMs in biological samples by mass spectrometry. © 2013 Elsevier Inc

Representational styles, their determinants and behavioral effect, an empirical study

Les typologies de parlementaires occupent une place centrale dans les études parlementaires.Nous proposons une définition du concept de «style de représentation», centrée sur lescaractéristiques déclarées des parlementaires - permettant de traiter les caractéristiques des élusdans leur diversité en examinant le spectre le plus large possible d’activités représentatives - et desaisir la manière dont ces activités s’articulent entre le niveau local et le niveau national. Ceconcept nous permettra d’étudier empiriquement les liens entre les styles de représentation -dansnotre cas des sénateurs français-, leurs déterminants et leurs effets comportementaux et desurmonter ainsi le descriptivisme propre à beaucoup d'études mobilisant des types parlementaires.L'analyse de cinq styles de représentation des sénateurs français met en évidence que les stylesde représentation sont des réponses aux contraintes et ressources des parlementaires et qu’ilsaffectent de manière systématique le comportement des sénateurs.Typologies of parliamentarians play a central role in the study of legislators and their behavior. Wepropose a narrow concept of styles of representation, focused on the expressed characteristics ofparliamentarians and taking into account the largest possible spectrum of representational activitiesincluding the local and the national arena of the mandate.This concept enables us to study empirically the links between styles of representations -in ourcase of French senators-, their determinants and behavioral effects and to overcome thedescriptiveness of many studies mobilizing typologies of parliamentarians.The analysis of five styles of representation of the French senators show, that these styles areanswers to the constraints and resources of the parliamentarians and that they affect the senators’behavior in a systematic manner

Les sénateurs français, parlementaires fantômes ?

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