53161 research outputs found
Sort by
Comprendre et prédire la phénologie du soja pour adapter la culture à de nouveaux environnements climatiques.
No full textL’exploration de nouvelles stratégies agronomiques (semis très précoce, expansion de la culture à des
latitudes plus élevées, double culture) pour augmenter la production de soja en Europe dans un
contexte de changement climatique impose de prévoir la phénologie de la culture dans des
environnements thermiques et photopériodiques variés. Dans cet objectif, le modèle (Simple
Phenology) de prédiction de la phénologie du soja a été calibré et évalué à partir de données
expérimentales. Pour la calibration, deux expériences ont été réalisées avec 10 génotypes contrastés
(groupes de maturité 000 à II) : 1- suivi phénologique de plantes en pots sur la plateforme HeliaphenINRA Toulouse avec 6 dates de semis, 2- réponse de la germination à la température en conditions
contrôlées. L’évaluation du modèle a été réalisée à partir d’essais multi-locaux menés dans le cadre du
projet SOJAMIP 2012-15 ainsi qu’à l’INRA Toulouse en 2017 et 2018. Les températures cardinales de
germination (Tmin, Topt et Tmax) sont proches de 0, 30 et 40°C ; avec des différences significatives de
sensibilité des variétés à la photopériode. Le modèle calibré avec un paramétrage variétal a montré une
RMSE de ~ 6 jours pour la prédiction du cycle cultural (i.e. stade cotylédons à maturité physiologique).
Coupler l’expérimentation et la modélisation agronomique permettra de positionner le cycle cultural de
variétés de soja dans de nouveaux environnements.Developing new cropping strategies (very early sowing, crop expansion at higher latitudes, double
cropping) to improve soybean production in Europe under climate change needs a good prediction of
phenology in different temperature and photoperiod conditions. For this aim, a soybean phenology
model was calibrated and evaluated using experimental data. Two experiments were carried out with 10
contrasting genotypes (maturity group 000 to II): 1- Phenological monitoring of plants in pots on the
Heliaphen platform with 6 sowing dates (INRA Toulouse). 2- Response of seed germination to
temperature in controlled conditions. Multilocal trials carried out as part of the SOJAMIP 2012-15 project
and at INRA Toulouse in 2017and 2018, were used to evaluate the phenology predicted by Simple [br/]
Phenology (SP) model. Cardinal temperatures (minimal, optimal and maximal) of germination were
close to 0, 30 and 40°C, respectively; with significant differences for photoperiod sensitivity among
varieties. The calibrated model with varietal parameters showed an RMSE of less than 6 days for the
prediction of crop cycle duration (i.e. cotyledons stage to physiological maturity). Combining
experimentation and agronomic modeling will make it possible to predict phenology of soybean
genotypes in new environments
Gestion des sols de vergers : panorama des outils et travaux, pistes pour la recherche
No full textSuite à l’enquête sur les sols de vergers lancée en 2016-2017, le GIS Fruits a lancé une étude pour approfondir et actualiser les bases scientifiques et techniques du maintien de la fertilité des sols de vergers, en lien avec les changements de pratiques (diminution des herbicides, utilisation de diverses formes de matière organique, enherbement permanent, …).
Les objectifs du rapport sont : la réalisation d’une synthèse des connaissances scientifiques et techniques sur la fertilité des sols de vergers, la cartographie des recherches existantes et la détermination de priorités de recherche en lien avec les acteurs agricoles
Yeast cell death caused by nutrient desequilibrium during alcoholic fermentation is impacted by nitrogen sources
No full textNutrients availability is a key factor for controlling wine alcoholic fermentation. Among them, nitrogen has been identified as an essential parameter, controlling both the fermentation rate and the durationof the fermentation. However, nitrogen is not sufficient to ensure a correct fermentation and other nutrients such as vitamins and lipids, present in lower quantities, are required. Furthermore, we showed in a previous study that an excess of nitrogen combined with a depletion in certain micronutrients can lead to cell death and sluggish or stuck fermentation. In this study, we provide evidence of the mechanism controlling cell death and we show that all the nitrogen sources are not equivalent in the initiation of this phenomenon.Fermentations limited in oleic acid, pantothenic acid and nicotinic acid showed yeast cell death linked to a high nitrogen content. In each case, lowering the nitrogen level restored yeast viability. We evidenced that yeast cell lack of a correct stress response to those micronutrient starvations in presence of high levels of nitrogen. A transcriptional analysis showed a correct stress response suggesting that the lack of resistance originates from a post-transcriptional control mechanism. We then provide evidence that the nitrogen Tor/Sch9 signaling pathway is involved in triggering cell death.Yeast cell viability was then monitored and compared during fermentation starting at different nitrogen levels, with the addition of different nitrogen sources (19 amino acids and NH4+) and two different timing of NH4+ addition. We observed that cell death was triggered with different intensities.Yeast cell death associated to disequilibrium between micronutrients and nitrogen has been evidenced and its implication on fermentations highlighted. We showed a strong impact of both the nature of the nitrogen source and time of addition on yeast cell death and fermentation outcome
Dupilumab provides important clinical benefits to patients with atopic dermatitis who do not achieve clear or almost clear skin according to the Investigator's Global Assessment: a pooled analysis of data from two phase III trials
No full textBackground In the U.S.A., an Investigator's Global Assessment (IGA) score of 1 at the end of treatment, using other validated outcome measures for AD signs, symptoms and quality of life. Methods LIBERTY AD SOLO 1 and 2 were two 16-week, randomized, double-blind trials enrolling adult patients with moderate-to-severe AD (IGA >= 3) inadequately controlled with topical treatment. We performed a post hoc analysis in patients receiving dupilumab 300 mg every 2 weeks (q2w) or placebo. Outcome measures in patients with IGA > 1 included Eczema Area and Severity Index (EASI), pruritus numerical rating scale (NRS), affected body surface area (BSA), Patient-Oriented Eczema Measure (POEM) and Dermatology Life Quality Index (DLQI). The trials were registered at ClinicalTrials.gov: NCT02277743 and NCT02277769. Results At week 16, 278 of 449 dupilumab q2w-treated patients (median age 36 center dot 0 years) and 396 of 443 placebo-treated patients had IGA > 1. Among patients with IGA > 1 at week 16, dupilumab significantly improved several outcome measures compared with placebo: EASI (-48 center dot 9% vs. -11 center dot 3%, P = 4-point improvement (57 center dot 4% vs. 21 center dot 0%, P = 4-point improvement (59 center dot 3% vs. 24 center dot 4%, P 1 at week 16, dupilumab induced statistically significant benefits in multiple validated outcome measures compared with placebo. The IGA <= 1 end point significantly underestimates clinically relevant dupilumab treatment effects
Specialization of small non-conjugative plasmids in Escherichia coli according to their family types
No full textWe undertook a comprehensive comparative analysis of a collection of 30 small (<25 kb) non-conjugative Escherichia coli plasmids previously classified by the gene sharing approach into 10 families, as well as plasmids found in the National Center for Biotechnology Information (NCBI) nucleotide database sharing similar genomic sequences. In total, 302 mobilizable (belonging to 2 MOBrep and 5 MOBRNA families) and 106 non-transferable/relaxase-negative (belonging to three ReLRNA families) plasmids were explored. The most striking feature was the specialization of the plasmid family types that was not related to their transmission mode and replication system. We observed a range of host strain specificity, from narrow E. coli host specificity to broad host range specificity, including a wide spectrum of Enterobacteriaceae. We found a wide variety of toxin/antitoxin systems and colicin operons in the plasmids, whose numbers and types varied according to the plasmid family type. The plasmids carried genes conferring resistance spanning almost all of the antibiotic classes, from those to which resistance developed early, such as sulphonamides, to those for which resistance has only developed recently, such as colistin. However, the prevalence of the resistance genes varied greatly according to the family type, ranging from 0 to 100 %. The evolutionary history of the plasmids based on the family type core genes showed variability within family nucleotide divergences in the range of E. coli chromosomal housekeeping genes, indicating long-term co-evolution between plasmids and host strains. In rare cases, a low evolutionary divergence suggested the massive spread of an epidemic plasmid. Overall, the importance of these small non-conjugative plasmids in bacterial adaptation varied greatly according to the type of family they belonged to, with each plasmid family having specific hosts and genetic traits
Differential susceptibility and innate immune response of Aedes aegypti and Aedes albopictus to the Haitian strain of the Mayaro Virus
No full textMayaro (MAYV) is an emerging arthropod-borne virus belonging to the Alphavirus genus of the Togaviridae family. Although forest-dwelling Haemagogus mosquitoes have been considered as its main vector, the virus has also been detected in circulating Aedes ssp mosquitoes. Here we assess the susceptibility of Aedes aegypti and Aedes albopictus to infection with MAYV and their innate immune response at an early stage of infection. Aedes albopictus was more susceptible to infection with MAYV than Ae. aegypti. Analysis of transcript levels of twenty immunity-related genes by real-time PCR in the midgut of both mosquitoes infected with MAYV revealed increased expression of several immune genes, including CLIP-domain serine proteases, the anti-microbial peptides defensin A, E, cecropin E, and the virus inducible gene. The regulation of certain genes appeared to be Aedes species-dependent. Infection of Ae. aegypti with MAYV resulted in increased levels of myeloid differentiation2-related lipid recognition protein (ML26A) transcripts, as compared to Ae. albopictus. Increased expression levels of thio-ester-containing protein 22 (TEP22) and Niemann-Pick type C1 (NPC1) gene transcripts were observed in infected Ae. albopictus, but not Ae. aegypti. The differences in these gene expression levels during MAYV infection could explain the variation in susceptibility observed in both mosquito species
