HAL Université des Antilles
Not a member yet
25497 research outputs found
Sort by
Interplay between host and environmental filters drives plant-associated microbiomes in the remote sub-Antarctic Kerguelen Islands
No full textInternational audienceBackground: Plants evolve as holobionts, ecological and evolutionary units made up of the host plant and its associated microbiota, which shape plant fitness and adaptive capacity. Isolated ecosystems with low biodiversity and plant cover, such as the fellfields of the remote sub-Antarctic Kerguelen Islands, represent ideal open-air laboratories to disentangle the drivers affecting plant-microbiome interactions. In such pristine environments, endemic plant species and their microbiota have coevolved in isolation possibly since the last ice age. In this study, we investigated the bacterial and fungal communities associated with different compartments (bulk and rhizospheric soils, roots, leaf surface and endosphere) of two phylogenetically distant endemic plants, the Poaceae Poa kerguelensis and the Brassicaceae Pringlea antiscorbutica, in fellfields with contrasted pedoclimatic conditions.Results: Using 16S and ITS metabarcoding, we identified a strong soil-plant compartment effect affecting microbial communities, with bacterial and fungal α-diversity higher in bulk and rhizospheric soils and progressively decreasing in roots and aerial compartments. The microbiota of the different plant compartments studied differ in their recruitment patterns. P. antiscorbutica showed a reduced dependence of its aerial bacterial communities on its underground communities compared to P. kerguelensis. We also showed that the microbiota of distinct plant species and their different soilplant compartments respond differently to pedo-climatic variables, with a greater impact of climatic variables than soil variables on above-ground bacterial microbiomes than on below-ground microbiomes.Conclusions: Our results highlight the dual role of environmental variability and of the identity of the host on the recruitment and diversity of plant microbiomes in the isolated ecosystems studied. They suggest that, in a context of global warming, plant species-specific microbial recruitment strategies and differential vulnerability to environmental factors may make it difficult to predict holobiont plant responses to environmental change
Evolution du magmatisme m´esozo¨ıque (240–90 Ma) dans le sud de l’´Equateur et le nord du Perou : avances geodynamiques issus de la petrochronologiedu zircon et de la geochimie des roches
No full textNational audienc
Encore une nouvelle espèce appartenant au genre Betaburmesebuthus Lourenço, 2015 retrouvée dans l’ambre Crétacé de Myanmar (Scorpiones : Paleoburmesebuthidae)
No full textInternational audienceOne more new species of fossil scorpion belonging to the genus Betaburmesebuthus Lourenço, 2015, is described from the Cretaceous amber of Myanmar (Burma). The new species is characterized by a combination of several morphological features and in particular a strongly elongated carapace with large median eyes, a conspicuous granulation on the telson and an aculeus enlarged at its base, and the absence of any major granulations or apophysis in both femur and patella of pedipalps. The description of the new species confirms, once again, that the genera of the family Palaeoburmesebuthidae are most certainly the most speciose among those found in the Burmese amber-producing forests.Encore une nouvelle espèce de scorpion fossile appartenant au genre Betaburmesebuthus Lourenço, 2015, est décrite de l’ambre Crétacé de Myanmar. La nouvelle espèce est caractérisée par un ensemble de structures morphologiques distinctes et en particulier par la présence d’une carapace prosomienne très allongée avec des gros yeux médians, un telson avec une granulation bien marquée et l’aiguillon quelque peu dilaté à sa base, et une absence de granules spiniformes ou apophyses aussi bien sur le fémur que le tibia des pédipalpes. La description de la nouvelle espèce confirme une fois de plus que les genres de la famille des Palaeoburmesebuthidae sont certainement parmi les plus riches en espèces entre ceux retrouvés dans l’ambre Crétacé de Myanmar
VEXAS anemia is a mosaic erythroblastopenia
No full textInternational audienceVEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) is a recently discovered autoinflammatory disorder linked to somatic mutations in the UBA1 gene, resulting in a profound cytoplasm-restricted defect in ubiquitylation. The disease is characterized by a macrocytic anemia that remains poorly understood. To investigate the erythroid lineage in VEXAS, we conducted a comprehensive study combining in vivo assessments of patients' mature red cells and marrow erythroblasts, alongside in vitro base-editing models of erythropoiesis. Here we show that mature red cells do not exhibit ubiquitylation defects, and patient-derived bone marrow erythroblasts lack UBA1 mutations beyond the basophilic stage of erythroid differentiation. In vitro base editing of UBA1 variants in CD34+ primary cells resulted in high mortality during early erythroid differentiation, but not during monocytic differentiation. Edited erythroid precursors displayed TP53 overexpression linked to defective ubiquitylation and anomalies in ribosome biogenesis, reminiscent of Diamond-Blackfan anemia. We propose that VEXAS-associated anemia should be considered as a mosaic erythroblastopenia, where the severity of anemia is influenced by the quality and quantity of the UBA1-WT compartment. Our findings offer new insights into the physiopathology of VEXAS and may suggest new potential therapeutic options
Aquatic metabolism influences temporal variations of water carbon and atmospheric carbon dioxide fluxes in a temperate salt marsh
No full textInternational audienceSalt marshes are blue carbon (C) ecosystems characterized by intense atmospheric CO2 uptake and C sequestration but also by organic and inorganic C exports through the tide. However, uncertainties about the main biotic factors controlling these vertical and horizontal C fluxes imply studying terrestrial and aquatic metabolisms simultaneously at small timescales (diurnal and tidal) to distinguish their contributions to net ecosystem CO2 exchange (NEE). In a temperate salt marsh, four sampling 24 h cycles were performed to measure all water C biogeochemical parameters (including CO2 partial pressures, pCO2), nutrients, and aquatic metabolism simultaneously to NEE from high tide during marsh immersion (imported coastal waters influenced by the continental shelf) to low tide during marsh emersion (exported channel waters influenced by the marsh drainage). At high tide, water CO2 oversaturation (water pCO2 > air pCO2) due to marsh aquatic heterotrophy and CO2-concentrated water inputs from the coastal end-member induced water–air CO2 emissions during marsh immersion. At low tide, water pCO2 in the channel were also mainly controlled by the marsh aquatic metabolism, inducing a water CO2 oversaturation in winter due to dominant heterotrophy and a water CO2 undersaturation in spring and summer due to dominant autotrophy. In winter, the greatest increases in dissolved inorganic carbon (DIC; from 2354 to 3963 µmol kg−1), total alkalinity (TA; from 2508 to 4016 µmol kg−1) and dissolved inorganic nitrogen (DIN; from 27.7 to 68.4 µM) were measured simultaneously during low tide at night, probably due to intense aerobic/anaerobic microbial respiration of organic matter in channel waters and/or sediments resulting in the greatest water pCO2 increase (from 533 to 1461 ppmv). On the contrary, in spring and summer, large water pCO2 decreases (down to 83 ppmv) and dissolved organic carbon (DOC) increases (up to 1040 µM) from high to low tide could be related to intense autochthonous and allochthonous marsh primary production, including benthic microalgae, phytoplankton and macroalgae. This study suggests that the horizontal exchanges of coastal waters with the salt marsh significantly modify water C dynamics and associated water CO2 sink/source state in the channel due to an intense marsh metabolism (production and respiration). At the daily scale, plant and phytoplankton metabolism rates played a major and a minor role, respectively, in the marsh CO2 sink measured by atmospheric eddy covariance at the ecosystem scale (NEE), even during immersion where emerged plants located on the highest marsh levels can maintain a low CO2 uptake, despite aquatic heterotrophy and associated water–air CO2 emissions
La historia debe mirarse en los ojos del mestizaje: el ejemplo de La Réunion (océano Índico)
No full textInternational audienc
État des lieux des connaissances sur l’alimentation des patients en situation de surpoids ou d’obésité en Guadeloupe : Gwodalim
No full textIntroduction: Overweight and obesity are major public health issues, particularly in Guadeloupe, where rates are higher than in mainland France. This study aims to assess the nutritional knowledge of patients with overweight or obesity in this region. Objectives: To conduct an assessment of nutritional knowledge among patients with overweight or obesity in Guadeloupe and to identify the factors influencing this knowledge. Methods: A cross-sectional observational study was conducted between July and October 2024 in 17 randomly selected general medical practices. Data were collected using a bilingual questionnaire (French or Creole) administered by a single investigator. Results: Among the 370 respondents, over half had an average level of knowledge, 31% had low knowledge, and 11% had good knowledge. Factors such as educational level and CMU/AME beneficiary status were significantly associated with the level of knowledge. Recommendations regarding sugary products and fish were better understood, whereas those concerning starchy foods and dairy products were less well known. Conclusion: Nutritional recommendations appear to be moderately well known among patients with overweight or obesity in Guadeloupe, with disparities depending on the type of food. This study highlights the need to tailor prevention and nutritional education campaigns to local specificities and the needs of vulnerable populations to reduce health disparities.Introduction : Le surpoids et l’obésité constituent des enjeux majeurs de santé publique, notamment en Guadeloupe, où les taux sont plus élevés qu’en France hexagonale. Cette étude vise à évaluer les connaissances alimentaires des patients en situation de surpoids ou d’obésité dans ce territoire. Objectifs : Réaliser un état des lieux des connaissances en matière d’alimentation chez les patients en situation de surpoids ou d’obésité en Guadeloupe et identifier les facteurs influençant ces connaissances. Méthodes : Une étude observationnelle transversale a été menée entre juillet et octobre 2024 dans 17 cabinets de médecine générale sélectionnés par tirage au sort. Les données ont été recueillies à l'aide d'un questionnaire bilingue (français ou créole) par un unique enquêteur. Résultats : Parmi les 370 répondants, plus de la moitié avaient un niveau de connaissance moyen, 31% des connaissances faibles, tandis que 11 % avaient de bonnes connaissances. Les facteurs comme le niveau d’étude et le statut de bénéficiaire de la CMU/AME étaient significativement associés au niveau de connaissance. Les recommandations sur les produits sucrés et le poisson étaient mieux maîtrisées, contrairement à celles sur les féculents et les produits laitiers. Conclusion : Les recommandations nutritionnelles semblent moyennement connues chez les patients en situation de surpoids ou d’obésité en Guadeloupe, avec des disparités selon les types d'aliments. Cette étude met en lumière la nécessité d’adapter les campagnes de prévention et d’éducation nutritionnelle aux spécificités locales et aux besoins des populations vulnérables pour réduire les disparités en matière de santé
From 1923 to 2023, a century of endemic malaria – Comoros can eliminate it?
No full textInternational audienceMalaria was first confirmed in Comoros in 1923 by Jean Raynal (Raynal, 1928), who in 1925 was appointed by the French colonial government to investigate a fatal epidemic in Grande Comore. Since then, malaria has become an endemic disease in the Comoros archipelago. In 2023, a century later, malaria remains a major health problem that the authorities are committed to eradicate. The aim of this demonstration is to retrace the evolution of malaria epidemiology from 1923 to 2023 in order to understand its decline and maintenance in Comoros. Thus, World Health Statistical Yearbooks and WHO World Malaria Reports, as well as the databases of the National Malaria Control Program (PNLP-Comores) were consulted to compile a database of malaria cases from 1923 to 2023. Using both historical and more recent sources of population data, the annual incidence of malaria was calculated for the three islands of the Union of Comoros. In parallel, data on various malaria control measures implemented during this period were recorded and used to examine their effects on the malaria evolution trend. The malaria epidemic of 1923 to 1925 caused over 2,500 deaths on Grande Comore alone. Malaria incidence averaged over 3,307 cases per 100,000 inhabitants between 1955 and 1976, less than 2,410 cases between 1993 and 1999, and over 7,360 cases between 2004 and 2009. From 2010 to 2017, incidence declined from 15,074 cases to less than 323 cases per 100,000 inhabitants, a 94% of reduction. However, since 2018, there has been a resurgence of malaria cases in Grande Comore, with incidence exceeding 1,000 cases per 100,000 inhabitants. This study showed how malaria has evolved in Comoros over a century, characterizing the effects of the control measures implemented: indoor residual spraying, mass distribution of insecticide-impregnated mosquito nets, mass treatment with Artequick, and improved diagnosis, care and treatment of patients. Comoros has been classified as a country in the malaria elimination phase, but definitive elimination remains a major challenge
Approche psychosociale, éducation interculturelle, clinique en contexte: Comment enseigner la clinique aux personnes opprimées?: Comment enseigner la clinique aux personnes opprimées?
No full textInternational audiencePsychosocial approach, intercultural education, contextualized clinic:How to teach the clinical approach to oppressed people?https://www.sociologie-clinique.org/france/wp-content/uploads/sites/13/2025/07/Joseph_R-M_diapo-colloque-RISC-LCSP-2025_16-juin.pd
From Preservation to Transformation: Taphonomic Analysis of Archaeological Insect Remains from the French Atlantic Coastline
No full textInternational audienceInsect remains can provide unique insights into past environments, yet their preservation and post-depositional alterations – particularly chromatic changes – remain poorly understood. Recent excavations along the French Atlantic coastline uncovered numerous archaeological structures dating from the Neolithic to Late Antiquity. Archaeoentomological samples collected from these structures reveal significant variations in the preserved insect remains. The frequency of morphological alterations, degree of fragmentation, and quantity of subfossil insects recovered vary between samples, influenced by the type of archaeological structure, the embedding substrate, the storage methods, and the taxa considered. Chromatic alterations, visible to the naked eye, appeared more uniform. This pilot study initially aimed to determine whether fibre-optic reflectance spectroscopy could detect original colouration no longer visible to the naked eye, by comparing archaeological specimens with modern reference material. Spectral analyses showed colour differences correspond to taphonomic alterations rather than hidden original hues. By documenting these changes and assessing spectroscopy’s applicability to archaeoentomological material, this study establishes a methodological baseline and reference dataset, opening new avenues for insect taphonomy research and improving palaeoenvironmental reconstructions