53161 research outputs found
Sort by
REPROSCOPE : l’observatoire de la reproduction des bovins en France
No full textLe projet REPROSCOPE a permis d’élaborer des outils pour accompagner la gestion de la reproduction
dans les troupeaux de bovins laitiers et allaitants. L’observatoire national de la reproduction bovine a
été créé. Il a une interface web accessible gratuitement permettant d’explorer les performances de
reproduction dans plus de 180 000 troupeaux bovins laitiers ou allaitants. À partir de la sélection d’une
population spécifique en fonction des caractéristiques des animaux ou des élevages, 20 performances
décrivent de façon homogène et exhaustive la reproduction à partir de moyennes et de distributions.
Les principaux enseignements issus de ce projet montrent une grande variabilité des performances de
reproduction et des impacts économiques, signe de marges de progrès envisageables. Grâce à l’outil
de positionnement, les éleveurs et leurs conseillers positionnent les performances d’un troupeau dans
un profil afin de faciliter la définition de marges de progrès envisageables. Une simulation économique
estime la plus-value à laquelle l’éleveur peut prétendre. REPROSCOPE facilite la définition d’objectifs
de reproduction cohérents avec le système d’élevage de l’exploitation en adéquation avec les attentes
des éleveurs.The REPROSCOPE project has developed tools to support the management of reproduction in both
dairy herds and suckler herds. The observatory has a web interface, available free of charge, which
makes it possible to explore breeding performances in more than 180 000 dairy or beef cattle herds.
After selecting a specific population according to animals or herds features, 20 performance indicators
describe reproductive results through averages and distributions under a homogeneous and
comprehensive way. The main lessons learned from this project show a great variability of reproductive
performances and economic impacts, highlighting room for future improvements. From the positioning
tool, farmers and their advisors can locate a herd performance among profiles, in order to facilitate
estimation of possible progress margins, and an economic simulation estimates the added value that
the farmer can expect. REPROSCOPE helps to define reproductive goals consistent with the farming
systems in connection with the breeders’ expectations
L’intérêt de dispositifs d’apprentissage organisationnels pour s’adapter à un contexte de changement : Exemples en élevage laitier et en coopérative laitière
No full textEn partant des principes et des concepts de l’innovation et de l’apprentissage organisationnel, nous montrons dans cette communication l’intérêt de mettre en place des dispositifs de pilotage stratégique permet-tant aux acteurs de s’adapter chemin faisant à un contexte agri alimentaire en évolution (mutations des marchés, des attentes des consommateurs, de la société sur les façons de produire, de l’environnement,...). Pour s’adapter – et tirer parti – de ces changements, les éleveurs et les filières doivent pouvoir faire évoluer leur organisation : avoir une lecture des changements de situation, raisonner la façon d’adapter en conséquences les règles et le fonctionnement du système, établir de nouvelles normes et valeurs au sein de l’organisation. Nous mettrons ici l’accent sur l’intérêt des concepts d’apprentissage organisationnel et d’objets intermédiaire pour mettre en place un dispositif et des outils permettant aux acteurs de suivre les changements de les analyser et de penser en cohérence une évolution de leur organisation. Nous prendrons deux exemples. L’un concerne l’autonomie fourragère en élevage. L’autre la gestion de la saisonnalité de la collecte laitière d’une coopérative.From principles and concepts of innovation and organizational learning, we will analyse in this com-munication the interest to implement strategic steering devices allowing the actors to adapt in the course ofaction to evolving context of agri food systems. This include changes in markets, consumers habits, concern-ment of society about livestock farming practices, environmental changes. To adapt and take advantage of thesechanges, the players in the agri-food sectors and farmers have to reshape accordingly their organizations. Be-ing resilient in the face of a situation of change is a real problem that requires both the flexibility to change androbustness to define rules that fit the organization. Here, we will focus on the interest to set up a device andtools, such as the logs, allowing the actors to follow changes to analyze and think an evolution of their organ-ization accordingly. We wiil take as examples questions about foraging autonomy at farm level on one handand on the other hand the management of saisonality of deliveries for a dairy cooperative
Supermarkets and their impacts on the relationship between food acquisition patterns and socio-economic and demographic characteristics of households: empirical evidence from Vietnam
No full textFood environments in developing economies are rapidly evolving, alongside fast-paced changes in the socioeconomic and demographic characteristics of populations. These changes are evident in Vietnam with the widespread emergence of supermarkets, and restructuring in traditional markets that are poised to have profound effects on household diets and patterns of food acquisition. This paper examines the relationship between province level supermarket density, quantity and quality indices of food groups acquired by households within those provinces, between 2010 and 2014. An original approach on the basis of open access mixed data sets (administrative data on the number of supermarkets at provincial level as a proxy for supermarket density, and household living standard survey) is proposed and implemented. We find that the differential presence of supermarkets across provinces in Vietnam is associated with the diversity and macronutrient quality of food groups acquired by households. In addition, households with higher per capita expenditure, and those that purchase a larger proportion of food (relative to food obtained from own production), acquire a higher diversity of food groups. Additionally, diversity of food acquired is associated with higher fat and lower carbohydrate shares, and this is independent of the presence of supermarkets. We observe a significant interplay between low household financial capabilities (i.e., low per capita expenditure and low proportion of income spent on food), large household size, ethnic minority status, and the existence of limited number of supermarkets in the food environment. All of these factors are associated with a limited diversity of food groups acquired, as well as higher carbohydrate and lower fat shares. Our findings highlight potential intervention opportunities that can “rewire” local food environments to address the challenge of double burden of malnutrition in the country
Elucidating the hot spot residues of quorum sensing peptidic autoinducer PapR by multiple amino acid replacements
No full textThe quorum sensing (QS) system of Bacillus cereus, an opportunistic human pathogen, utilizes the autoinducing PapR peptide signal that mediates the activation of the pleiotropic virulence regulator PlcR. A set of synthetic 7-mer PapR-derived peptides (PapR(7); ADLPFEF) have been shown to inhibit efficiently the PlcR regulon activity and the production of virulence factors, reflected by a loss in hemolytic activity without affecting bacterial growth. Interestingly, these first potent synthetic inhibitors involved D-amino acid or alanine replacements of three amino acids; proline, glutamic acid, and phenylalanine of the heptapeptide PapR. To better understand the role of these three positions in PlcR activity, we report herein the second generation design, synthesis, and characterization of PapR(7)-derived combinations, alternate double and triple alanine and D-amino acids replacement at these positions. Our findings generate a new set of non-native PapR(7)-derived peptides that inhibit the PlcR regulon activity and the production of virulence factors. Using the amino acids substitution strategy, we revealed the role of proline and glutamic acid on PlcR regulon activation. Moreover, we demonstrated that the D-Glutamic acid substitution was crucial for the design of stronger PlcR antagonists. These peptides represent potent synthetic inhibitors of B. cereus QS and constitute new and readily accessible chemical tools for the study of the PlcR system. Our method might be applied to other quorum sensing systems to design new anti-virulence agents
Differential homotypic and heterotypic interactions of antigen 43 (Ag43) variants in autotransporter-mediated bacterial autoaggregation
No full textAntigen 43 (Ag43) is a cell-surface exposed protein of Escherichia coli secreted by the Type V, subtype
a, secretion system (T5aSS) and belonging to the family of self-associating autotransporters (SAATs).
These modular proteins, comprising a cleavable N-terminal signal peptide, a surface-exposed central
passenger and an outer membrane C-terminal translocator, self-recognise in a Velcro-like handshake
mechanism. A phylogenetic network analysis focusing on the passenger revealed for the first time
that they actually distribute into four distinct classes, namely C1, C2, C3 and C4. Structural alignment
and modelling analyses demonstrated these classes arose from shuffling of two different subdomains
within the Ag43 passengers. Functional analyses revealed that homotypic interactions occur for all
Ag43 classes but significant differences in the sedimentation kinetics and aggregation state were
present when Ag43C3 was expressed. In contrast, heterotypic interaction occurred in a very limited
number of cases. Single cell-force spectroscopy demonstrated the importance of specific as well as
nonspecific interactions in mediating Ag43-Ag43 recognition. We propose that structural differences in
the subdomains of the Ag43 classes account for different autoaggregation dynamics and propensities to
co-interact
Mode of action and engineering of a rice NLR immune receptor for broader recognition specificity of Magnaporthe oryzae effectors
No full textExploration of the growth-virulence trade-off in the plant pathogen Ralstonia solanacearum species complex
No full textR. solanacearum is one of the most devastating plant pathogens for agriculture due to its aggressiveness, its wide host spectrum, its vast geographical distribution and its long persistence in the soil. In many countries it infects many important crops (tomato, ginger, potato, bananas, tobacco …). On potato alone, it is responsible for an estimated $1 billion US in losses each year world-wide. It can also survive for years in soil, thus preventing the culture of susceptible hosts for long periods of time. When detected, is a source of major constraints for agriculture. Ralstonia solanacearum is now defined as a species complex composed of hundreds different strains and divided in four major phylotypes. Few strains are described as hostspecific, but most of them have similar lifecycles and can invade many hosts. Recently, we used a systems biology approach to show the existence of a trade-off between growth and virulence for the strain GMI1000 (Peyraud et al., 2016). Indeed, virulence traits such as excretion of exopolysaccharides or construction of a type III secretion system are costly in terms of energy, carbon and nitrogen, impacting the growth rate. The pathogen has to decide how to invest its resources between growth (hence proliferation) and virulence (thus defense/attack against the plant). This trade-off was experimentally validated by showing that avirulent mutants grows faster than the wild type. Here, we will present experimental and systems biology results investigating how much this trade-off is conserved among different strains of the R. solanacearum species complex. We will show that strains have different trophic preferences and metabolic adaptation, which can be linked to their lifestyle
DNA Metabarcoding to quantify the ecological impact of climate-induced forest diebacks in the Pyrenees
No full textPhylogeography of Puumala orthohantavirus in Europe
No full textPuumala virus is an RNA virus hosted by the bank vole (Myodes glareolus) and is today present in most European countries. Whilst it is generally accepted that hantaviruses have been tightly co-evolving with their hosts, Puumala virus (PUUV) evolutionary history is still controversial and so far has not been studied at the whole European level. This study attempts to reconstruct the phylogeographical spread of modern PUUV throughout Europe during the last postglacial period in the light of an upgraded dataset of complete PUUV small (S) segment sequences and by using most recent computational approaches. Taking advantage of the knowledge on the past migrations of its host, we identified at least three potential independent dispersal routes of PUUV during postglacial recolonization of Europe by the bank vole. From the Alpe-Adrian region (Balkan, Austria, and Hungary) to Western European countries (Germany, France, Belgium, and Netherland), and South Scandinavia. From the vicinity of Carpathian Mountains to the Baltic countries and to Poland, Russia, and Finland. The dissemination towards Denmark and North Scandinavia is more hypothetical and probably involved several independent streams from south and north Fennoscandia
Causative links between protein aggregation and oxidative stress: a review
No full textCompelling evidence supports a tight link between oxidative stress and protein aggregation processes, which are noticeably involved in the development of proteinopathies, such as Alzheimer's disease, Parkinson's disease, and prion disease. The literature is tremendously rich in studies that establish a functional link between both processes, revealing that oxidative stress can be either causative, or consecutive, to protein aggregation. Because oxidative stress monitoring is highly challenging and may often lead to artefactual results, cutting-edge technical tools have been developed recently in the redox field, improving the ability to measure oxidative perturbations in biological systems. This review aims at providing an update of the previously known functional links between oxidative stress and protein aggregation, thereby revisiting the long-established relationship between both processes