Portail HAL ONIRIS VetAgroBio Nantes
Not a member yet
11563 research outputs found
Sort by
Identification of miR-187 as a modulator of early oogenesis and female fecundity in medaka
No full textInternational audienceMicroRNAs (miRNAs) are known regulators of ovarian function in vertebrates, yet their physiological roles in fish reproduction remain poorly understood. Here, we identified miR-187 as one of the most ovarian-enriched miRNAs in medaka (Oryzias latipes) and we uncovered its function in vivo using CRISPR/Cas9-mediated gene inactivation. We showed that miR-187-3p is expressed in oocytes and granulosa cells in the ovary, and in discrete brain areas. Its loss-of-function lead to a significant reduction in female fecundity. High-resolution 3D imaging of whole ovaries revealed that mir-187 mutants accumulate early stage I follicles and show reduced progression to later stages, indicating a defect in early follicle recruitment and growth. Transcriptomic profiling of mutant ovaries revealed extensive gene-expression remodeling, including downregulation of key regulators of steroidogenesis, Wnt/β-catenin signaling, and TGF-β pathways, and upregulation of genes associated with early follicle activation and immature somatic cell states. Using an expression-based target-prediction pipeline, we identified several putative miR-187-3p targets, including nr6a1a (gcnf) and dpagt1, two genes previously implicated in oocyte differentiation and female fertility in mammals. Together, our results demonstrate that miR-187 acts as a previously unrecognized regulator of early folliculogenesis and female reproductive capacity in medaka, expanding the repertoire of miRNAs with essential in vivo roles in teleost oogenesis and female fecundity
Comprehensive characterization of organic compounds present in chlordecone commercial formulations (Kepone and Curlone) applied in the French West Indies using gas and liquid chromatography hyphenated with high resolution mass spectrometry
No full textInternational audienceChlordecone (CLD) was widely used in French West Indies (FWI) until 1993 against black banana weevil (Cosmopolites sordidus). However, this pesticide was determined to have various adverse effects such as increasing the frequency of prostate cancer and impacting infant's neurological development. It is thus a highly monitored compound in FWI environmental, food and biological matrices. CLD represents the major organic component (5 % by weight) of the commercial formulations used in the past, although some other compounds are expected to be present. This study investigates the overall organic chemical composition of six Curlone formulations and of one sample of technical Kepone to identify compounds other than CLD that can be present in these formulations and still unknown. Chemical analysis was performed using both gas chromatography and liquid chromatography hyphenated with high resolution mass spectrometry, while data processing was conducted using non-target analysis. The overall investigation lead to the detection of 52 chlorinated molecules and 16 non-chlorinated molecules ranging from 1 % to 1 part-per-million (ppm) of the CLD intensity. Tentatively identified compounds were some CLD isomers, mirex, chlordecol, monohydro-and/or dihydroCLD, chlorocyclopentadienes, chloronaphthalenes, chlorobutadienes, chloroindanes, chloroindenes and chlorocyclopentenes for chlorinated compounds, and cyclic hydrocarbons, oxygenated hydrocarbons and linear alkanes for non-chlorinated compounds. Even if some compounds were detected at low percentages, the high quantity used for these formulations in the French West Indies makes the overall quantity of these compounds non-negligible, and thus future studies could investigate these compounds in environmental, food and biological matrice
Contrasting Q fever perception among European large animal veterinary practitioners, 2024
No full textInternational audienc
Mammalian mesenchymal stromal cells enhance zebrafish fin regeneration
No full textInternational audienceMesenchymal stromal cells (MSCs) possess well-described immunoregulatory properties, yet their capacity to drive regeneration in vertebrates is still debated and their mechanisms of action remain to be fully elucidated. In this study, we used zebrafish larvae, a highly regenerative vertebrate model to study the effects of MSC delivery on caudal fin fold regeneration and monitored macrophage dynamics through live imaging in fluorescent reporter lines. We found that MSCs enhanced fin regeneration by increasing the early recruitment of inflammatory (tnfa +) macrophages at 1-day-post-amputation (dpA), and accelerating resolution between 2 and 3 dpA. Given the established role of prostaglandin E2 (PGE2) in MSC-mediated immunoregulation, we examined its contribution using indomethacin, a cyclooxygenase inhibitor that suppresses PGE2 production in grafted MSCs. We observed that PGE2 inhibition abolished the pro-regenerative effect of MSCs and maintained elevated tnfa + macrophage levels. PGE2-inhibited MSCs were more susceptible to phagocytosis by both zebrafish and mammalian macrophages, while maintaining viability, indicating a loss of PGE2-mediated protection in treated cells. Together, these findings demonstrate that MSC-derived PGE2 is essential for MSC regenerative function by promoting MSC persistence and modulating macrophage behavior, highlight the zebrafish as a powerful in vivo platform to dissect stem cell-immune interactions and optimize MSCbased regenerative strategies
The Origins of Neuromuscular Electrodiagnosis, 1800–1950: A Crucial Period
No full textInternational audienc
Multiphoton microscopy and tissue clearing for 3D characterization of the vasculature and fibrosis remodeling in rat dystrophic skeletal muscle
No full textInternational audienc
État des lieux de la reproduction en captivité des tatous à six bandes (Euphractus sexcinctus) en Europe et suivi du cycle oestral à l'aide d'une méthode non invasive : le dosage des stéroïdes fécaux
No full textArmadillo reproduction remains poorly understood, limiteing their ex situ management. The six-banded armadillo (Euphractus sexcinctus), a species relatively common in captivity, represents a relevant model to improving this knowledge. This thesis aimed to evaluate the reproduction of the species through two complementary approaches : a European husbandry survey and an experimental study based on non-invasive endocrine monitoring. Two questionnaires were distributed to 50 institutions, with a response rate of 64% (32 zoos). The results revealed a high heterogeneity of husbandry and reproductive practices. Several recurring difficulties were highlighted, notably neonatal mortality, the absence of standardized protocols, and variability in pregnancy monitoring. Exploratory statistical analyses did not identify any significant husbandry factors associated with reproductive success, underlining the need for more standardized and comparable data. In parallel, hormonal monitoring was conducted on four females through fecal measurements of estrogens and progesterone, combined with external clinical observation. Profiles consistent with estrous cycles were identified in two individuals, while an abortion and an absence of cyclic activity suggesting of ovarian senescence were observed in the other two. These results constitute the first non-invasive endocrine data obtained for the species and demonstrate the feasibility of this approach. This work provides an first reproductive knowledge base for E. sexcinctus in captivity and emphasizes the importance of centralizing data and harmonizing practices among institutions. It also confirms the potential of this species as a model for develop ex situ conservation strategies applicable to other xenarthrans, several of which are threatened.La reproduction des tatous reste mal connue, limitant leur gestion ex situ. Le tatou à six bandes (Euphractus sexcinctus), espèce relativement commune en captivité, constitue un modèle pertinent pour améliorer ces connaissances. Cette thèse visait à évaluer la reproduction de l’espèce à travers deux approches complémentaires : une enquête zootechnique européenne et une étude expérimentale basée sur un suivi endocrinien non invasif. Un questionnaire a été diffusé auprès de 5 établissements, avec un taux de réponse de 64% (32 zoos). Les résultats montrent une forte hétérogénéité des pratiques d’élevage et de reproduction. Certaines difficultés sont récurrentes, notamment la mortalité néonatale, l’absence de protocoles harmonisés et la variabilité du suivi des gestations. Les analyses statistiques exploratoires n’ont pas mis en évidence de facteurs zootechniques significatifs associés au succès reproductif, soulignant la nécessité de données plus standardisées. En parallèle, un suivi hormonal a été conduit chez quatre femelles à l’aide de dosages fécaux d’œstrogènes et de progestérone, couplés à l’observation clinique externe. Des profils compatibles avec des cycles œstraux ont été identifiés chez deux individus, tandis qu’un avortement et une absence d’activité cyclique suggérant une sénescence ovarienne ont été observés chez les deux autres. Ces résultats constituent les premières données endocriniennes non invasives obtenues pour l’espèce et démontrent la faisabilité de cette approche. Ces travaux apportent une première base de connaissances reproductives pour E. sexcinctus en captivité et soulignent l’importance de centraliser les données et d’harmoniser les pratiques entre établissements. Ils confirment également le potentiel de l’espèce comme modèle pour développer des stratégies de conservation ex situ applicables à d’autres xénarthres, dont plusieurs sont menacés
Unveiling the role of mir-187 in promoting adult ovarian follicle growth and female fecundity in medaka (Oryzias latipes)
No full textInternational audienc
Combinaison de modèles physiques et d’apprentissage automatique pour la modélisation de systèmes multi-énergies
No full textThe massive integration of intermittent renewable energy sources necessitates more complex energy systems with stronger coupling between energy sectors, expanded storage capacities, and more dynamic operation. Model-based decision-making is essential to efficiently design and operate these systems. However, pure physics-based models are often too computationally expensive for real-time applications. Machine Learning (ML) offers high speed and accuracy but suffers from limited interpretability and generalizability. This thesis explores hybrid modeling approaches that combine physics-based and ML models to achieve both speed and accuracy while maintaining interpretability and generalizability. It provides a classification of the fundamental building blocks and design patterns of hybrid modeling, then proposes novel hybrid models for Thermal Energy Storage (TES) and Heat Pump (HP) systems. The hybrid TES model runs approximately 1250x faster with overall mean squared error below 0.48°C2, while the hybrid HP model achieves a 271× speed-up with error below 0.4%. Both models demonstrate improved accuracy and generalizability while requiring less training data than pure ML models. In the second part, both models are evaluated on two case studies, (1) the operation of charging and discharging a TES in a solar power plant, and (2) the operation of a HP coupled with a hot water tank to provide heating for a building. These studies demonstrate the usability of the proposed models for real-time applications. Both models were successfully integrated into Model Predictive Control workflows to optimally operate the systems.L'intégration massive de sources d'énergie renouvelables intermittentes nécessite des systèmes énergétiques plus complexes et dynamiques, exploitant des capacités de stockage accrues et une synergie entre les secteurs énergétiques. La prise de décision basée sur des modèles est essentielle pour concevoir et exploiter efficacement ces systèmes. Cependant, les modèles purement physiques sont souvent trop coûteux en termes de calcul pour les applications en temps réel. L'apprentissage automatique est une alternative offrant des temps de calcul intéressants, mais souffre d'une interprétabilité et d'une généralisation limitées. Cette thèse s’intéresse aux modèles hybrides qui combinent les deux approches. Elle commence par classer les éléments constitutifs et les architectures possibles de ces modèles, puis propose des modèles hybrides pour deux technologies différentes : (1) le stockage d'énergie thermique et (2) les pompes à chaleur. Le modèle hybride de stockage thermique est environ 1250 fois plus rapide que le modèle de référence, avec une erreur quadratique moyenne inférieure à 0,48 °C². Le modèle hybride de pompe à chaleur est 271 fois plus rapide que le modèle de référence, avec une erreur inférieure à 0,4 %. Les deux modèles ont montré une capacité de généralisation plus importante et des besoins en données d’entraînement plus limités que les réseaux de neurones classiques. Dans la deuxième partie, deux cas d’études sont utilisés pour évaluer l’utilité des modèles hybrides : (1) le pilotage d’un stockage d’énergie thermique dans une centrale solaire, et (2) l’opération d’une pompe à chaleur couplée à un réservoir d’eau chaude pour chauffer un bâtiment. Ces études montrent que les modèles proposés sont adaptés à des applications en temps réel. Les deux modèles ont été intégrés avec succès dans des boucles de commande prédictive (MPC) afin d’optimiser le fonctionnement des deux cas étudiés
Impact of the "3°C of Change" initiative on the shelf-life of frozen foods: the role of temperature oscillations during frozen storage.
No full textInternational audienceThe international standard for frozen foods is -18°C (0°F). The "Three-Degrees-of change" initiative proposesto explore the interest of raising from -18°C to -15°C the frozen storage temperature in order to save energy.The analysis on the impact of this initiative on the quality of frozen foods shows that a 30% loss in shelf lifeis expected for food stored at -15°C compared to -18°C. A focus is proposed in this study on the impact oftemperature oscillation during storage; indeed, in the case of foods with a lower initial freezing point (ie IFPof -5°C vs -1°C), a same temperature oscillation will result in a larger change in LOF and aw. Therefore, theshelf life is likely to be more affected in a food with a lower IFP