Extrasynaptic and Postsynaptic Receptors in Glycinergic and GABAergic Neurotransmission: A Division of Labor?

Glycine and GABA mediate inhibitory neurotransmission in the spinal cord and central nervous system. The general concept of neurotransmission is now challenged by the contribution of both phasic activation of postsynaptic glycine and GABAA receptors (GlyRs and GABAARs, respectively) and tonic activity of these receptors located at extrasynaptic sites. GlyR and GABAAR kinetics depend on several parameters, including subunit composition, subsynaptic localization and activation mode. Postsynaptic and extrasynaptic receptors display different subunit compositions and are activated by fast presynaptic and slow paracrine release of neurotransmitters, respectively. GlyR and GABAAR functional properties also rely on their aggregation level, which is higher at postsynaptic densities than at extrasynaptic loci. Finally, these receptors can co-aggregate at mixed inhibitory postsynaptic densities where they cross-modulate their activity, providing another parameter of functional complexity. GlyR and GABAAR density at postsynaptic sites results from the balance between their internalization and insertion in the plasma membrane, but also on their lateral diffusion from and to the postsynaptic loci. The dynamic exchange of receptors between synaptic and extrasynaptic sites and their functional adaptation in terms of kinetics point out a new adaptive process of inhibitory neurotransmission

Why is lateral root growth so variable? A framework to analyze growth variability among lateral roots and the possible roles of auxin and carbon

International audienceLateral root (LR) development is a major component of the efficiency of a plant to capture soil resources. A remarkable facet of lateral root behavior is stochasticity affecting the different stages of LR growth, leading to a large range of lateral root lengths along the primary root. It has been argued that such variability among LR could be an adaptive trait enabling a greater plasticity and efficiency of the root system in front of the spatial and temporal heterogeneity of soil resources (Forde, 2009). In order to characterize variability in LR growth and evaluate the role of hormonal and biochemical signals that might influence it, we analyzed the patterns of development of hundreds of lateral roots in a set of maize seedlings grown in rhizotrons. The SmartRoot toolbox was used to provide a comprehensive recording of individual root growth dynamics. Using a clustering method based on growth variables such as elongation rate and growth duration, we could identify 3 main different elongation patterns in maize LRs composed of accelerating, slowly decelerating and rapidly arrested LRs, as found in other species (Pagès, 1995). The molecular and cellular characterization of these root types revealed differences in meristem size, apical diameters as well as apical diameter variation. Moreover, fast growing roots showed increased sugar content along their tips. Finally, by affecting either the sugar or the auxin status (by pruning seminal roots or using auxin transport mutants) we differentially altered the proportion of the different root types, suggesting that both signals contribute to shape the root system in response to variations of environmental conditions.FORDE, B. (2009), J. Exp. Bot. 60 (14): 3989-4002PAGES, L. (1995), New Phytologist, 130: 503–50

VETESS : IDM, Test et SysML

Selected paper from the 7-th NEPTUNE WorkshopNational audienceIl apparaît souvent que les processus d'ingénierie système sont en fait décomposés en phases discontinues oùtrop peu d'informations sont partagées entre les différentes équipes, par exemple entre les équipes de design et de tests.Cette faiblesse peut être palliée par l’utilisation de modèles de spécifications qui jouent alors le rôle de référentiel pourl’ensemble des équipes participant au cycle de vie du logiciel. Ce type de modèle est couramment utilisé comme basedans les activités de conception, de vérification, ou encore de test. Le test basé sur les modèles est une approcheoriginale où sont automatiquement générés des cas de test et des scripts de test exécutables à partir d'une spécificationdu système sous test. Cette spécification prend la forme d'un modèle comportemental, permettant ainsi au générateur detests de déterminer, d'une part, quels sont les contextes d'exécution pertinents et, d'autre part, de prédire les effets sur lesystème de ces exécutions. Le but du projet VETESS est de rendre possible cette approche pour valider les systèmesembarqués automobiles. Il s’agit ainsi de mettre en œuvre et d’outiller un processus automatique permettant de dériver,d'un modèle de spécification décrit avec un sous-ensemble du langage de modélisation SysML, des cas de test, et deproduire ensuite les scripts de test correspondants à exécuter sur banc de test automobiles

Swine Influenza Virus Antibodies in Humans, Western Europe, 2009

Serologic studies for swine influenza viruses (SIVs) in humans with occupational exposure to swine have been reported from the Americas but not from Europe. We compared levels of neutralizing antibodies against 3 influenza viruses—pandemic (H1N1) 2009, an avian-like enzootic subtype H1N1 SIV, and a 2007–08 seasonal subtype H1N1—in 211 persons with swine contact and 224 matched controls in Luxembourg. Persons whose profession involved contact with swine had more neutralizing antibodies against SIV and pandemic (H1N1) 2009 virus than did the controls. Controls also had antibodies against these viruses although exposure to them was unlikely. Antibodies against SIV and pandemic (H1N1) 2009 virus correlated with each other but not with seasonal subtype H1N1 virus. Sequential exposure to variants of seasonal influenza (H1N1) viruses may have increased chances for serologic cross-reactivity with antigenically distinct viruses. Further studies are needed to determine the extent to which serologic responses correlate with infection

Using metabolic networks to resolve ecological properties of microbiomes

The systematic collection, integration and modelling of high-throughput molecular data (multi-omics) allows the detailed characterisation of microbiomes in situ. Through metabolic trait inference, metabolic network reconstruction and modelling, we are now able to define ecological interactions based on metabolic exchanges, identify keystone genes, functions and species, and resolve ecological niches of constituent microbial populations. The resulting knowledge provides detailed information on ecosystem functioning. However, as microbial communities are dynamic in nature the field needs to move towards the integration of time- and space-resolved multi-omic data along with detailed environmental information to fully harness the power of community- and population-level metabolic network modelling. Such approaches will be fundamental for future targeted management strategies with wide-ranging applications in biotechnology and biomedicine

Specific involvement of atypical PKCζ/PKMζ in spinal persistent nociceptive processing following peripheral inflammation in rat.

BACKGROUND: Central sensitization requires the activation of various intracellular signalling pathways within spinal dorsal horn neurons, leading to a lowering of activation threshold and enhanced responsiveness of these cells. Such plasticity contributes to the manifestation of chronic pain states and displays a number of features of long-term potentiation (LTP), a ubiquitous neuronal mechanism of increased synaptic strength. Here we describe the role of a novel pathway involving atypical PKCζ/PKMζ in persistent spinal nociceptive processing, previously implicated in the maintenance of late-phase LTP. RESULTS: Using both behavioral tests and in vivo electrophysiology in rats, we show that inhibition of this pathway, via spinal delivery of a myristoylated protein kinase C-ζ pseudo-substrate inhibitor, reduces both pain-related behaviors and the activity of deep dorsal horn wide dynamic range neurons (WDRs) following formalin administration. In addition, Complete Freund's Adjuvant (CFA)-induced mechanical and thermal hypersensitivity was also reduced by inhibition of PKCζ/PKMζ activity. Importantly, this inhibition did not affect acute pain or locomotor behavior in normal rats and interestingly, did not inhibited mechanical allodynia and hyperalgesia in neuropathic rats. Pain-related behaviors in both inflammatory models coincided with increased phosphorylation of PKCζ/PKMζ in dorsal horn neurons, specifically PKMζ phosphorylation in formalin rats. Finally, inhibition of PKCζ/PKMζ activity decreased the expression of Fos in response to formalin and CFA in both superficial and deep laminae of the dorsal horn. CONCLUSIONS: These results suggest that PKCζ, especially PKMζ isoform, is a significant factor involved in spinal persistent nociceptive processing, specifically, the manifestation of chronic pain states following peripheral inflammation

Les Pédo-paysages des plaines centrales de Midi-Pyrénées

Les sols des zones de plaines de la région Midi-Pyrénées montrent une grande diversité liée, notamment, au carrefour des influences climatiques passées et actuelles : glaciaire, méditerranéenne et atlantique. Le présent article illustre la distribution des principales Unités Typologiques de Sols parmi les Unités pédo-paysagères dans les zones de plaines depuis le nord du Lot jusqu'au piémont ariégeois. La couverture pédologique y est très marquée par la nature des grands ensembles sédimentaires, depuis les contreforts du Massif central, jusqu'à la Molasse argilo-calcaire très largement étendue dans le bassin toulousain

Acción : diario de Teruel y su provincia: Año III Número 633 - (11/12/34)

New types of phenotyping tools generate large amounts of data on many aspects of plant physiology and morphology with high spatial and temporal resolution. These new phenotyping data are potentially useful to improve understanding and prediction of complex traits, like yield, that are characterized by strong environmental context dependencies, i.e., genotype by environment interactions. For an evaluation of the utility of new phenotyping information, we will look at how this information can be incorporated in different classes of genotype-to-phenotype (G2P) models. G2P models predict phenotypic traits as functions of genotypic and environmental inputs. In the last decade, access to high-density single nucleotide polymorphism markers (SNPs) and sequence information has boosted the development of a class of G2P models called genomic prediction models that predict phenotypes from genome wide marker profiles. The challenge now is to build G2P models that incorporate simultaneously extensive genomic information alongside with new phenotypic information. Beyond the modification of existing G2P models, new G2P paradigms are required. We present candidate G2P models for the integration of genomic and new phenotyping information and illustrate their use in examples. Special attention will be given to the modelling of genotype by environment interactions. The G2P models provide a framework for model based phenotyping and the evaluation of the utility of phenotyping information in the context of breeding programs.</p

Brucella Control of Dendritic Cell Maturation Is Dependent on the TIR-Containing Protein Btp1

Brucella is an intracellular pathogen able to persist for long periods of time within the host and establish a chronic disease. We show that soon after Brucella inoculation in intestinal loops, dendritic cells from ileal Peyer's patches become infected and constitute a cell target for this pathogen. In vitro, we found that Brucella replicates within dendritic cells and hinders their functional activation. In addition, we identified a new Brucella protein Btp1, which down-modulates maturation of infected dendritic cells by interfering with the TLR2 signaling pathway. These results show that intracellular Brucella is able to control dendritic cell function, which may have important consequences in the development of chronic brucellosis

Hopanoid-free Methylobacterium extorquens DM4 overproduces carotenoids and has widespread growth impairment

Hopanoids are sterol-like membrane lipids widely used as geochemical proxies for bacteria. Currently, the physiological role of hopanoids is not well understood, and this represents one of the major limitations in interpreting the significance of their presence in ancient or contemporary sediments. Previous analyses of mutants lacking hopanoids in a range of bacteria have revealed a range of phenotypes under normal growth conditions, but with most having at least an increased sensitivity to toxins and osmotic stress. We employed hopanoid-free strains of Methylobacterium extorquens DM4, uncovering severe growth defects relative to the wild-type under many tested conditions, including normal growth conditions without additional stressors. Mutants overproduce carotenoids–the other major isoprenoid product of this strain–and show an altered fatty acid profile, pronounced flocculation in liquid media, and lower growth yields than for the wild-type strain. The flocculation phenotype can be mitigated by addition of cellulase to the medium, suggesting a link between the function of hopanoids and the secretion of cellulose in M. extorquens DM4. On solid media, colonies of the hopanoid-free mutant strain were smaller than wild-type, and were more sensitive to osmotic or pH stress, as well as to a variety of toxins. The results for M. extorquens DM4 are consistent with the hypothesis that hopanoids are important for membrane fluidity and lipid packing, but also indicate that the specific physiological processes that require hopanoids vary across bacterial lineages. Our work provides further support to emerging observations that the role of hopanoids in membrane robustness and barrier function may be important across lineages, possibly mediated through an interaction with lipid A in the outer membrane