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Les profils alimentaires aux Antilles françaises : que sait-on de l’exposition au chlordécone et de son coût monétaire alimentaire ?
No full textNational audienceContexte : La Guadeloupe et la Martinique font face à un triple défi : une exposition de la population au chlordécone, pesticide organochloré persistant ; une augmentation des maladies chroniques d’origine alimentaire ; des contraintes économiques limitant l’accès à une alimentation saine. Les circuits informels comme l’autoproduction peuvent réduire les coûts mais accroître l’exposition au chlordécone. Cette étude évalue les coûts alimentaires et l’exposition au chlordécone de quatre profils alimentaires identifiés précédemment : « sain », « traditionnel », « pratique » et « en transition ». Méthodes : Les données proviennent de l’enquête Kannari (2013-2014) auprès de 1105 adultes antillais. Les consommations alimentaires ont été recueillies par deux rappels de 24 heures et un questionnaire de fréquence alimentaire. L’exposition au chlordécone a été estimée en croisant les données de consommation avec les niveaux de contamination des aliments, selon leur origine (circuit formel ou informel). Les coûts alimentaires ont été calculés selon les circuits d’approvisionnement. Les tests de Kruskal-Wallis et de Dunn-Bonferroni ont permis de comparer les profils. Résultats : Le profil « en transition » présente l’exposition au chlordécone la plus élevée, liée à la consommation de poissons marins achetés en bord de route et de crustacés offerts. Ce profil affiche aussi le coût alimentaire le plus élevé (4,80 €/jour). Les profils « moderne » et « sain » montrent des coûts similaires (3,71 €/jour vs 4,34 €/jour) mais une qualité nutritionnelle opposée. Conclusions : Les profils « moderne » et « sain » comparables en coût, mais opposés en qualité de l'alimentation montrent que le prix n’est pas un obstacle à une alimentation saine. De plus, le profil « en transition » présente le coût et l'exposition au chlordécone les plus élevés, mais une qualité de l'alimentation intermédiaire. Les politiques de santé publique devraient donc cibler en priorité les individus « en transition » pour promouvoir des choix alimentaires plus sûrs, nutritifs et économiquement viable
Re-evaluation of the nodulation capacity of Sphingomonas sediminicola DSM 18106 T indicates that this strain is not capable of inducing root nodule formation on Pisum sativum (pea)
No full textInternational audienceRhizobia are soil-dwelling proteobacteria that can enter into symbiotic nitrogen-fixing relationships with compatible leguminous plants. Taxonomically, rhizobia are divided into alpha-rhizobia, which belong to the class Alpharoteobacteria, and beta-rhizobia, which belong to the class Betaproteobacteria. To date, all bona fide alpha-rhizobia belong to the order Hyphomicrobiales. However, a recent study suggested that Sphingomonas sediminicola DSM 18106 T is also a rhizobium and is capable of nodulating pea plants ( Pisum sativum), which would expand the known taxonomic distribution of alpha-rhizobia to include the order Sphingomonadales. Here, we attempted to replicate the results of that previous study. Resequencing and computational analysis of the genome of S. sediminicola DSM 18106 T failed to identify genes encoding proteins involved in legume nodulation or nitrogen fixation. In addition, experimental plant assays indicated that S. sediminicola DSM 18106 T is unable to nodulate the two cultivars of pea tested in our study, unlike the rhizobium Rhizobium johnstonii 3841 T . Taken together, and in contrast to the previous study, these results suggest that S. sediminicola DSM 18106 T is not capable of inducing root nodule formation on pea, meaning that the taxonomic distribution of all known alpha-rhizobia remains limited to the class Hyphomicrobiales
Does income inequality influence health vulnerability to pollution? Evidence from France
No full textThis study investigates whether income inequality within a population influences the health effects of pollution. Specifically, we empirically estimate the causal impact of particulate matter (PM 10 ) on mortality in France, using wind direction as an instrumental variable, and explore how income inequality modifies this relationship. Our findings reveal a statistically and economically significant impact of pollution exposure on the mortality of individuals aged 50 or older, which intensifies in municipalities with higher levels of income inequality. More precisely, while the effect of PM 10 is not significant in municipalities with the lowest levels of disparities, it is significant for the others and increases with the level of inequality within the municipalities. The impact of PM 10 on the mortality of individuals aged 50 or older in the top 33% of municipalities with the highest inequality is up to twice as large as in municipalities with intermediate levels of inequality. This result is particularly striking given that it concerns a country like France, which has relatively low income inequality. To provide a comprehensive understanding of the potential underlying mechanisms, we develop a theoretical model and empirically test its predictions. We conclude that the observed variation in vulnerability to pollution across municipalities, stratified by inequality levels, could have been but is not attributable to differences in public health expenditure, pollution exposure (between and within municipalities), or poverty prevalence and intensity. Our results suggest that inequality plays a significant role in environmental health, worthy of further research
Elucidation of the symbiotic incompatibility mechanisms between Vigna radiata and Bradyrhizobium vignae ORS3257 mediated by nodulation outer protein P2
No full textInternational audienceBradyrhizobium vignae ORS3257 is an efficient symbiotic strain for Vigna unguiculata and V. mungo but fails with V. radiata due to an effector-triggered immunity response mediated by the nodulation outer protein P2 (NopP2). To understand this incompatibility, we identified NopP2 interacting proteins in V. radiata cv. KPS1, including enolase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), monodehydroascorbate reductase (MDHAR), and serine hydroxymethyltransferase (SHMT) as targets. Protein-protein interaction assays confirmed that NopP2 binds to these enzymes, and further analysis revealed their co-localization on the plasma membrane. Comparative transcriptomic analysis revealed NopP2 stimulates genes related to plant defense response (PR1, PR5, MYB13, and TAO1), hydrogen peroxide (SOD, POX10, and POX16), and cell wall lignification (LAC). NopP2 did not alter the expression of genes encoding the target enzymes but interfered with MDHAR activity, leading to high H2O2 accumulation in roots. These findings suggest that NopP2 contributes to symbiotic incompatibility in V. radiata by inducing a multifaceted defense response and initiating cell wall lignification early in infection
Quels leviers pour des trajectoires d’adaptation aux risques côtiers ? L’exemple de la région Occitanie
No full textInternational audienceThis article aims to identify the levers that facilitate the implementation of progressive public action in terms of adaptation trajectories in the face of climate change on the coast. It is based on 18 interviews and various observations conducted as part of a multidisciplinary project in the Occitanie region, France. The main levers identified concern representations, modes of governance and territorial engineering tools. More generally, the article highlights the importance of collective learning effects, and of the structuring of a steering capacity by territorial engineering professionals.Cet article vise à identifier les leviers facilitant la mise en place d’une action publique progressive en termes de trajectoires d’adaptation face au changement climatique sur le littoral. Il est basé sur 18 entretiens et diverses observations menés dans le cadre d’un projet pluridisciplinaire en région Occitanie. Les principaux leviers identifiés concernent les représentations, les modes de gouvernance et les outils de l’ingénierie territoriale. Plus généralement, l’article met en avant l’importance des effets d’apprentissages collectifs, et de la structuration d’une capacité de pilotage par les acteurs de l’ingénierie territoriale
Fibrillarin Contributes to the Oncogenic Characteristics of Colorectal Cancer Cells and Reduces Sensitivity to 5-Fluorouracil
No full textInternational audienceBackground/Objectives: Fibrillarin (FBL) is a key nucleolar methyltransferase involved in ribosome biogenesis through 2′-O-ribose methylation of rRNA. While its oncogenic role has been reported in several cancer types, its expression and function in human colorectal cancer (CRC) have remained largely unexplored. This study aims to investigate the expression of FBL in human CRC tissues and cell lines and to determine its functional role in tumor progression and metastasis.Methods: We examined FBL expression in paired human CRC primary tumors and liver metastases using immunohistochemistry. Functional studies were performed using SW-480 (primary tumor) and SW-620 (lymph node metastasis) CRC cell lines derived from the same patient. Cell migration, invasion, and 3D spheroid growth were analyzed following FBL downregulation. In vivo tumor growth was assessed in SCID mice xenografted with FBL-deficient cells. Molecular changes were explored through phosphorylation arrays and Western blotting.Results: FBL expression was significantly higher in human metastatic lesions than in primary tumors. FBL downregulation impaired migration, invasion, and spheroid growth in SW-480 and SW-620 cells and reduced tumor growth in vivo. Mechanistically, FBL inhibition decreased activation of MAPK/ERK, PI3K/AKT, and JNK/p38 pathways and reduced phosphorylation of the transcription factor CREB.Conclusions: Our study identifies FBL as a potential contributor to colorectal cancer progression, with elevated expression associated particularly with metastatic disease. By demonstrating that FBL expression is elevated in patient-derived metastatic tissues and functionally promotes migration, invasion, and tumor growth, our findings expand the role of ribosome biogenesis factors beyond protein synthesis. The observed suppression of key oncogenic pathways and CREB phosphorylation upon FBL inhibition suggests that FBL integrates ribosomal regulation with cancer cell signaling. These insights open new avenues for targeting nucleolar activity in advanced CRC and highlight FBL as a potential biomarker and therapeutic target in metastatic disease
Enhancing PROSAIL Inversion: Key Considerations and Practical Insights
No full textInternational audienceAccurate estimation of plant biophysical properties is essential for understanding ecosystem functioning, monitoring forest health, productivity, and assessing the risk of disturbances. However, retrieval accuracy is often constrained by uncertainties in model parameterization, soil background effects, and spectral redundancy. This study systematically evaluates the influence of parameter range, band selection, and soil background on the inversion of leaf area index, chlorophyll content, leaf mass per area, and equivalent water thickness in Eucalyptus plantations throughout an entire growing season. Retrievals were conducted by inverting the PROSAIL model. Our approach led to three innovative findings: 1) the integration of trait-informed parameter ranges, tailored to Eucalyptus plantations, which substantially improves retrieval accuracy, especially for leaf mass per area; 2) the demonstration that band selection can reduce root mean square error by up 58% for Chlorophyll content, 52% leaf mass per area and 69% for equivalent water thickness; and 3) the performance of soil background datasets strongly depends on the sampling strategy used and whether band selection was applied. These findings highlight that combining spectral optimization with contextual prior knowledge provides a robust framework for improving PROSAIL inversion in forest ecosystems, advancing remote sensing applications for plantation monitoring and sustainable management of natural resources. Moreover, this work presents a rarely explored application of PROSAIL inversion to forest plantations, extending its use beyond crop studies
Urban Market Gardening Improves Soil Health: A Case Study in Burkina Faso
No full textInternational audienceIn sub-Saharan Africa, urban market gardening is characterized by the intensive use of chemical inputs, which could have adverse effects on soil health. This study therefore aimed to assess the impact of urban market gardening on soil health. Topsoil samples were collected from 69 plots at a market gardening site in Bobo-Dioulasso, Burkina Faso, with cultivation histories ranging from 0 to over 50 years. Twenty-six chemical, biological, and physical soil properties were analyzed. Principal component analysis was used to identify minimum data sets for the assessment of soil health. The selected variables were standardized and aggregated into two soil health indices on a scale from 0 to 100: an overall index based on all properties combined and an average index based on the mean of the biological, physical, and chemical components of soil health. Both indices revealed a clear improvement in soil health over time, with the overall index rising from an initial value of 0.35 to 0.64 after 60 years and the average index rising from 0.30 to 0.62. The average index, which enables the separate assessment of its three components, accounted for a greater share of the temporal variability (R 2 = 0.59) than the overall index (R 2 = 0.47). These findings highlight the positive impact of urban market gardening practices on soil health at the study site, which was attributed to the large additions of organic amendments.</div
Comment une animation régionale peut-elle aider à structurer une filière bio, régionale et équitable ?: Exemple de la filière brassicole bio occitane
No full textCe mémoire s'inscrit dans une démarche de contribution à la structuration des filières biologiques régionales. Il propose une analyse de l'utilisation de la méthodologie de chemin d'impact ImpresS développée par le CIRAD, afin de préciser le rôle d'ABBIO, association interprofessionnelle régionale. Habituellement mobilisée pour l'évaluation d'impact à visée recherche, cette méthodologie a montré son intérêt par sa capacité d'adaptation à la construction d'un plan d'action opérationnel pour l'association. Elle offre en effet une approche systémique permettant de saisir la complexité des interactions qui traversent la structuration des filières bio. Dans la partie méthodologique, je détaille les étapes de mon adaptation de cette démarche. Les résultats présentent ensuite, de façon progressive, le plan d'action élaboré grâce à cette méthode, jusqu'à la formalisation du chemin d'impact, qui constitue la théorie du changement d'ABBIO. Ce document, aboutissement de mon travail, éclaire ainsi la place et les missions de l'association dans le développement de la filière brassicole biologique en Occitanie. Il fournit également à ABBIO un outil stratégique pour piloter et ajuster ses actions en fonction des impacts visés.</div
The maize mitogen‐activated protein kinase kinase kinase gene <i>ZmMAPKKK45</i> is associated with multiple disease resistance
No full textInternational audienceSouthern leaf blight (SLB), caused by the necrotrophic fungus Cochliobolus heterostrophus, is a major foliar disease of maize (Zea mays) world-wide.A genome-wide association study was performed to dissect the genetic basis of SLB resistance in maize. Functional validation was performed using mutant and transgenic analyses. Molecular experiments provided preliminary insights into the underlying disease resistance mechanisms.Association analyses identified 14 single nucleotide polymorphisms (SNPs) linked to SLB resistance, 13 of which overlapped with known quantitative resistance loci, highlighting 10 candidate genes. Functional studies confirmed ZmMAPKKK45, encoding a mitogen-activated protein kinase kinase kinase (MAPKKK), is the causal gene at a resistance locus on chromosome 3. ZmMAPKKK45 also enhanced resistance to northern leaf blight and gray leaf spot and promotes reactive oxygen species (ROS) accumulation during defense responses.Our results indicate that ZmMAPKKK45 functions outside canonical MAPK cascades and likely enhances disease resistance by upregulating maize respiratory burst oxidase homolog (ZmRBOH) genes, thereby increasing ROS production and contributing to broad-spectrum foliar disease resistance in maize.</div