Nicotinic receptors mediate stress-nicotine detrimental interplay via dopamine cells’ activity

Epidemiological studies report strong association between mood disorders and tobacco addiction. This high comorbidity requires adequate treatment but the underlying mechanisms are unknown. We demonstrate that nicotine exposure, independent of drug withdrawal effects, increases stress sensitivity, a major risk factor in mood disorders. Nicotine and stress concur to induce long-lasting cellular adaptations within the dopamine (DA) system. This interplay is underpinned by marked remodeling of nicotinic systems, causing increased ventral tegmental area (VTA) DA neurons’ activity and stress-related behaviors, such as social aversion. Blocking β2 or α7 nicotinic acetylcholine receptors (nAChRs) prevents, respectively, the development and the expression of social stress-induced neuroadaptations; conversely, facilitating α7 nAChRs activation specifically in the VTA promotes stress-induced cellular and behavioral maladaptations. Our work unravels a complex nicotine-stress bidirectional interplay and identifies α7 nAChRs as a promising therapeutic target for stress-related psychiatric disorders

Planck pre-launch status : The Planck mission

Peer reviewe

Modeling N dynamics to assess environmental impacts of cropped soils

Models are useful tools to evaluate environmental impacts associated with nitrogen management in cropping systems and to predict them correctly. The purpose of this chapter was to analyze whether existing models satisfactorily simulate N losses in agroecosystems, require input data that are accessible, and can incorporate agricultural and climatic changes. The literature on 62 nitrogen models was reviewed. Each model was analyzed to identify the processes simulated, the equations used, the time and space scales, the input data and their degree of accessibility, and finally its performance. The review showed that a wide range of formalisms have been developed to model N processes. N losses such as nitrate leaching give better performance than N gas emissions, underlining the need to improve the understanding and modeling of denitrification and volatilization. It also revealed the narrow range of crop families parameterized and validated with field measurements. The main trend in modeling over the last 15 years has been the shift from mechanistic models to functional models, with a simplification of the equations involved and an aggregation of modules according to specific objectives. The more recent models have thus generally been based on specific contexts and cannot be directly extrapolated to other pedoclimatic and crop contexts, yet this is necessary for evaluating scenarios involving changes in land use and management or climatic uncertainties

Near infrared reflectance spectroscopy : a tool to characterize the composition of different types of exogenous organic matter and their behaviour in soil

In addition to total organic carbon and nitrogen, potential organic carbon mineralization under controlled laboratory conditions and indicators such as the indicator of remaining organic carbon in soil (I-ROC), based on Van Soest biochemical fractionation and short-term carbon mineralization in soil, are used to predict the evolution of exogenous organic matter (EOM) after its application to soils. The purpose of this study was to develop near infrared reflectance spectroscopy (NIRS) calibration models that could predict these characteristics in a large dataset including 300 EOMs representative of the broad range of such materials applied to cultivated soils (plant materials, animal manures, composts, sludges. etc.). The NIRS predictions of total organic matter and total organic carbon were satisfactory (R(2)p = 0.80 and 0.85, ratio of performance to deviation, RPDp = 2.2 and 2.6, respectively), and prediction of the Van Soest soluble, cellulose and holocellulose fractions were acceptable (R(2)p = 0.82, 0.73 and 0.70. RPDp = 2.3, 1.9 and 1.8, respectively) with coefficients of variation close to those of the reference methods. The NIRS prediction of carbon mineralization during incubation was satisfactory and indeed better regarding the short-term results of mineralization (R(2)p = 0.78 and 0.78, and RPDp = 2.1 and 2.0 for 3 and 7 days of incubation, respectively). The I-ROC indicator was predicted with fairly good accuracy (R(2)p = 0.79, RPDp = 2.2). Variables related to the long-term C mineralization of EOM in soil were not predicted accurately, except for I-ROC which was based on analytical and well-identified characteristics, probably because of the increasing interactions and complexity of the factors governing EOM mineralization in soil as a function of incubation time. This study demonstrated the possibility of developing NIRS predictive models for EOM characteristics in heterogeneous datasets of EOMs. However. specific NIRS predictive models still remain necessary for sludges, organo-mineral fertilizers and liquid manures

Réseau PRO : Création d'un réseau d'essais au champ et d'un outil de mutualisation des données pour l'étude de la valeur agronomique et des impacts environnementaux des Produits Résiduaires Organiques recyclés enagriculture

Ce 49ème volume de la Revue Innovations Agronomiques regroupe l'ensemble de la restitution des projets Casdar, présentés le 3 novembre 2015.The "PRO Network” project (2011-2014) has enabled the creation of a national network of trials investigating the effects of agricultural organic waste products (PRO) applications in very different agropedo-climatic situations and for a range of applied PRO. This network was firstly, to harmonize the methods of study and follow-up effects of PRO applied to the field, and secondly to pool data acquired on a wide range of field trials. Have thus been developed: an inventory of 437 tests of PRO in France, an operational methodological guide of field test on the PRO, a method of referencing of the PRO with a first draft of nomenclature, and an information system shared by PRO network and the PRO SOERE. Collected data led to improve the setting of the tools developed within the RMT fertilization & environment (Tools for environmental diagnosis and management of fertilization and the Organic Statute of the soil). Finally, the critical analysis of pooled data sets resulted in recommendations for future trials.Le projet « Réseau PRO » (2011-2014) a permis la constitution d’un réseau national d’essais étudiant les effets des épandages agricoles de produits résiduaires organiques (PRO) dans des situations agropédo-climatiques très différentes et pour une grande diversité de PRO épandus. Ce réseau visait d’une part, à harmoniser les méthodes d’étude et de suivi des effets des PRO épandus au champ, et d’autre part à mutualiser les données acquises sur une grande diversité d’essais au champ. Ont ainsi été élaborés : un inventaire de 437 essais étudiant les PRO en France, un guide méthodologique opérationnel de conduite d’essai de plein champ sur les PRO, une méthode de référencement des PRO et une première ébauche de nomenclature, et un système d’information commun au Réseau PRO et au SOERE PRO. Par ailleurs, les données recueillies ont permis d’améliorer le paramétrage des outils développés au sein du RMT Fertilisation & Environnement (outils de diagnostic environnemental et de gestion de la fertilisation et du statut organique des sols). Enfin, l’analyse critique des jeux de données mutualisés a donné lieu à des recommandations pour les futurs essais