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Genomic Divergence Shaped the Genetic Regulation of Meiotic Homologous Recombination in Brassica Allopolyploids
No full textInternational audienceThe tight regulation of meiotic recombination between homologs is disrupted in Brassica AAC allotriploids, a genomic configuration that may have facilitated the formation of rapeseed (Brassica napus L.) ∼7,500 years ago. Indeed, the presence of the haploid C genome induces supernumerary crossovers between homologous A chromosomes with dramatically reshaped distribution. However, the genetic mechanisms driving this phenomenon and their divergence between nascent and established lineages remain unclear. To address these concerns, we generated hybrids carrying additional C chromosomes derived either from an established lineage of the allotetraploid B. napus or from its diploid progenitor B. oleracea. We then assessed recombination variation across twelve populations by mapping male meiotic crossovers using single nucleotide polymorphism markers evenly distributed across the sequenced A genome. Our findings reveal that the C09 chromosome of B. oleracea is responsible for the formation of additional crossovers near pericentromeric regions. Interestingly, its counterpart from an established lineage of B. napus shows no significant effect on its own, despite having a similar content of meiotic genes. However, we showed that the B. napus C09 chromosome influences crossover formation through inter-chromosomal epistatic interactions with other specific C chromosomes. These results provide new insights into the genetic regulation of homologous recombination in Brassica and emphasize the role of genomic divergence since the formation of the allopolyploid B. napus
Cytosolic Monodehydroascorbate Reductase 2 Promotes Oxidative Stress Signaling in Arabidopsis
No full textInternational audienceThe antioxidative enzyme monodehydroascorbate reductase (MDHAR) is represented by five genes in Arabidopsis, including four that encode cytosolic and peroxisomal proteins. The in planta importance of these specific isoforms during oxidative stress remain to be characterised. T‐DNA mutants for MDAR genes encoding cytosolic and peroxisomal isoforms were studied. To examine their roles in conditions of intracellular oxidative stress, mutants were crossed with a cat2 line lacking the major leaf catalase. Enzyme assays in mdar mutants and of recombinant MDHARs suggest that peroxisomal MDHAR1 and cytosolic MDHAR2 are major players in leaf NADH‐ and NADPH‐dependent activities, respectively. All mutants showed a wild‐type phenotype when grown in standard conditions. In the cat2 background, loss of peroxisomal MDHAR functions decreased growth whereas loss of the cytosolic MDHAR2 function had no effect on growth but annulled a large part of transcriptomic and phenotypic responses to oxidative stress. The effects of the mdar2 mutation included decreased salicylic acid accumulation and enhanced glutathione oxidation, and were reverted by complementation with the MDAR2 sequence. Together, the data show that the cytosolic MDHAR2 is dispensable in optimal conditions but essential to promote biotic defence responses triggered by oxidative stress
Nature's best vs. bruised: A veggie edibility evaluation database
No full textInternational audienceIn the realm of evaluating vegetable freshness, automated methods that assess external morphology, texture, and colour have emerged as efficient and cost-effective tools. These methods play a crucial role in sorting high-quality vegetables for both export and local consumption, significantly impacting the revenue of the food industry worldwide. Researchers have recognized the importance of this area, leading to the development of various automated techniques, particularly leveraging advanced deep learning technologies to categorize vegetables into specific classes. However, the effectiveness of these methods heavily relies on the databases used for training and validation, posing a challenge due to the lack of suitable datasets
‘Risking the dark to see the light’: Scoring Predictive Policing and Personal Loss in Minority Report (Spielberg, 2002)
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TDP-43 nuclear retention is antagonized by hypo-phosphorylation of its C-terminus in the cytoplasm
No full textInternational audienceProtein aggregation is a hallmark of many neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), in which TDP-43, a nuclear RNA-binding protein, forms cytoplasmic inclusions. Here, we have developed a robust and automated method to assess protein self-assembly in the cytoplasm using microtubules as nanoplatforms. Importantly, we have analyzed specifically the self-assembly of full-length TDP-43 and its mRNA binding that are regulated by the phosphorylation of its self-adhesive C-terminus, which is the recipient of many pathological mutations. We show that C-terminus phosphorylation prevents the recruitment of TDP-43 in mRNA-rich stress granules only under acute stress conditions because of a low affinity for mRNA but not under mild stress conditions. In addition, the self-assembly of the C-terminus is negatively regulated by phosphorylation in the cytoplasm which in turn promotes TDP-43 nuclear import. We anticipate that reducing TDP-43 C-terminus self-assembly in the cytoplasm may be an interesting strategy to reverse TDP-43 nuclear depletion in neurodegenerative diseases
Vertigineux réseaux : enjeux éthiques, cliniques et politiques
No full textInternational audienceEn parallèle de l’avènement d’un individu hypermoderne, hybride et complexe, des fractures multiples fragilisent nos sociétés. Quels rôles jouent les technologies numériques dans ces bouleversements sociaux et politiques ? Au-delà des clichés et des discours simplificateurs, les auteurs de disciplines variées proposent des réflexions sur ces vertigineux réseaux sociaux : leur influence, les pratiques sociales qui les nourrissent, l’évolution des jeux de pouvoir entre États et géants du numérique, la place des médias ou les orientations – réelles ou supposées – d’une métamorphose que nous serions en train de vivre. L’ouvrage invite ainsi à prendre du recul sur l’agitation permanente et apporte des outils de compréhension et d’analyse critique de notre condition numérique, à travers une variété de questions éthiques, cliniques et politiques qu’elle fait émerger
A complex interplay between histone variants and DNA methylation
No full textInternational audienceNucleosomes, the chromatin building blocks, play an important role in controlling DNA and chromatin accessibility. Nucleosome remodeling and the incorporation of distinct histone variants confer unique structural and biochemical properties, influencing the targeting of multiple epigenetic pathways, particularly DNA methylation. This stable epigenetic mark suppresses transposable element expression in plants and mammals, serving as an additional layer of chromatin regulation. In this review we explore recent advances in our understanding of the complex interplays between histone variants and DNA methylation in plants, and discuss the role that chromatin remodeling plays in coordinating histone exchange and methylation of DNA
Decathlon ou les tactiques de la vertu : sociologie politique d'une entreprise citoyenne
No full textInternational audienceL'enseigne Decathlon se dit soucieuse du bien-être de ses salariés et de son engagement sur tous les territoires où elle est implantée. Cet ouvrage restitue l’origine, les usages et les limites de ces « tactiques de la vertu ». L'entreprise peut-elle sauver la planète et l’humanité ? Un discours enchanté affirme aujourd’hui qu’un capitalisme vertueux est possible, capable de combiner performance économique et défense de l’intérêt général. Au moyen de politiques de responsabilité sociale et environnementale (RSE), les firmes seraient à l’origine de nouvelles pratiques qui permettraient de produire conjointement une « entreprise citoyenne » et un « citoyen d’entreprise » ajusté à celle-ci.Decathlon, géant français de la distribution sportive, est l’incarnation de ce modèle d’entrepreneuriat. Présente dans 70 pays et employant plus de 100 000 personnes à travers le monde, l’enseigne se dit soucieuse du bien-être de ses salariés et de son engagement sur tous les territoires où elle est implantée. Pour autant, les logiques de développement et de concurrence entrent souvent en contradiction avec les intentions vertueuses revendiquées par le groupe, ce qui suscite de nombreuses critiques.Du Nord de la France aux magasins flambant neufs du Mexique ou du Sénégal, en passant par les usines tunisiennes de confection, cet ouvrage restitue l’origine, les usages et les limites de ces « tactiques de la vertu »
A coupled stabilized scheme on decoupled finite smoothed particle hydrodynamics and distributed contact discrete element method to simulate fluid-rigid-body interaction with multibody contacts
No full textInternational audienceThis study suggests a coupled stabilized numerical scheme on fluid-rigid-body interaction with multibody contacts. A compatible model combines the decoupled strategy originally from finite particle method in weakly compressible smoothed particle hydrodynamics scheme (conveniently summarized as decoupled finite smoothed particle hydrodynamics, DFSPH) and a distributed contact discrete element method (DCDEM) to construct complicated geometrical multibody contact frame in fluid-structure interaction. Based on the developed graphics processing unit (GPU) parallel computing architecture in three dimensions (3D), numerical investigations on solid-fluid mixture flows and dam breaking with ice floating blocks are proceeded to verify the availability of present algorithm and diversified treatments. Nonlinear thermal-mechanical dynamic behaviors on fluid-structure interaction are furtherly investigated involving the opening heat exchanging conduction and dissipation on free surface. Analytical results show that these physical information on experiments can be efficiently captured by present numerical scheme, which has the preferable performance and potential industrial applicability
A hackathon for flood map prediction from geospatial data with parsimonious machine learning models
No full textInternational audienceFlooding poses significant risks across various sectors in France. This paper presents the outcomes of a machine learning hackathon focused on predicting the extent of various types of floods by leveraging a combination of geospatial and climate data. A Convolutional Neural Network (CNN) emerged as the most effective model, achieving strong performance in predicting the temporal evolution of flood risk maps. The evaluation not only includes prediction accuracy but also incorporates robustness, frugality, and explainability, in line with the principles of trustworthy AI principles. A key feature of this challenge was the absence of streamflow data, allowing the models to predict floods in regions where such data is unavailable. This highlights the potential of machine learning to improve flood forecasting in data-scarce environments.2 Hackathon setup 2.1 Geospatial Data Labels: Flood maps were extracted from the Sen1Floods11 dataset [2] which can be visualized on the Global Flood Database. Sen1Floods11 provides surface water data, including raw Sentinel-1 WIP paper.</div