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Actes de la rencontre consacrée à Jean-Alexandre Buchon, Ecole française d'Athènes (26-27 octobre 2023)
No full textInternational audienceThis volume brings together 10 texts on the work of Jean-Alexandre Buchon (1791-1846) on Frankish Greece, examining the historian's method, his relationship with the legacy of Charles Du Cange, and his epistemological contribution to medieval studies.Ce volume rassemble 10 textes relatifs aux travaux que Jean-Alexandre Buchon (1791-1846) a consacrés à l'étude de la Grèce franque ; ils examinent la méthode utilisée par l'historien, sa relation à l'héritage laissé par Charles Du Cange, son apport épistémologique à la médiévistique
Ce que les humains font avec la vie
No full textInternational audienceComment coexister avec le vivant dans des environnements écologiques toujours plus dégradés ? Comment construire des conditions de vie atténuant les inégalités entre les vies humaines et favorisant une meilleure qualité de vie ? Comment faire un usage responsable des biotechnologies ? Comment faire cohabiter la diversité des rapports au monde développés par les sociétés humaines, en prenant en compte leurs attachements à des milieux de vie variés ? Ces quatre questions, étroitement liées, s’articulent à une interrogation centrale pour notre époque : comment vivre sur la planète Terre ?À l’interface entre le vital et le social, ces enjeux ne concernent pas seulement les sciences comme l’écologie et la biologie. Ils sont au cœur de la réflexion dans un domaine en pleine effervescence : l’anthropologie de la vie. Partout dans le monde, les humains perçoivent la vie comme un pouvoir qui exerce son emprise sur les êtres vivants, produisant des effets – croissance, reproduction, vieillissement, mort – sur les corps. Dans uneperspective comparatiste, ce livre met en lumière la manière dont les enquêtes ethnographiques aident à mieux comprendre comment les sociétés s’organisent autour d’un tel pouvoir et de la fragilité des vies humaines qui en dépend
Globular cluster orbital decay in dwarf galaxies with MOND and CDM: Impact of supernova feedback
No full textInternational audienceDynamical friction works very differently for Newtonian gravity with dark matter and in modified Newtonian dynamics (MOND). While the absence of dark matter considerably reduces the friction in major galaxy mergers, analytic calculations indicate the opposite for very small perturbations, such as globular clusters (GCs) sinking in dwarf galaxies. Here, we study the decay of GCs in isolated gas-rich dwarf galaxies using simulations with the Phantom of Ramses code, which enables both the Newtonian and the QUMOND MOND gravity. We modeled the GCs as point masses, and we simulated the full hydrodynamics, with star formation and supernovae feedback. We explored whether the fluctuations in gravitational potential caused by the supernovae can prevent GCs from sinking toward the nucleus. For GCs of typical mass or lighter, we find that this indeed works in both Newtonian and MOND simulations. The GC can even make a random walk. However, we find that supernovae cannot prevent massive GCs (M ≥ 4 × 10 5 M ) from sinking in MOND. The resulting object looks similar to a galaxy with an offset core, which embeds the sunk GC. The problem is much milder in the Newtonian simulations. This result thus favors Newtonian over QUMOND gravity, but we note that it relies on the correctness of the difficult modeling of baryonic feedback. We propose that the fluctuations in the gravitational potential could be responsible for the thickness of the stellar disks of dwarf galaxies and that strong supernova winds in modified gravity can transform dwarf galaxies into ultra-diffuse galaxies.</div
Integrated analysis of whole blood oxylipin and cytokine responses after bacterial, viral, and T cell stimulation reveals new immune networks
No full textInternational audienceOxylipins are major immunomodulating mediators, yet studies of inflammation focus mainly on cytokines. Here, using a standardized whole-blood stimulation system, we characterized the oxylipin-driven inflammatory responses to various stimuli and their relationships with cytokine responses. We performed a pilot study in 25 healthy individuals using 6 different stimuli: 2 bacterial stimuli (LPS and live BCG), 2 viral stimuli (vaccine-grade poly I:C and live H1N1 attenuated influenza), an enterotoxin superantigen and a Null control. All stimuli induced a strong production of oxylipins but most importantly, bacterial, viral, and T cell immune responses show distinct oxylipin signatures. Integration of the oxylipin and cytokine responses for each condition revealed new immune networks improving our understanding of inflammation regulation. Finally, the oxylipin responses and oxylipin-cytokine networks were compared in patients with active tuberculosis or with latent infection. This revealed different responses to BCG but not LPS stimulation highlighting new regulatory pathways for further investigations
The oncogenic role of Streptococcus gallolyticus subsp. gallolyticus is linked to activation of multiple cancer-related signaling pathways
No full textPosted February 22, 2023 on bioRxiv.International audienceStreptococcus gallolyticus subsp. gallolyticus (SGG), an opportunistic gram-positive pathogen responsible for septicemia and endocarditis in the elderly, is often associated with colon cancer (CRC). In this work, we investigated the oncogenic role of SGG strain UCN34 using the azoxymethane (AOM)-induced CRC model in vivo, organoid formation ex vivo and proteomic and phosphoproteomic analyses from murine colons. We showed that SGG UCN34 accelerates colon tumor development in the murine CRC model. Full proteome and phosphoproteome analysis of murine colons chronically colonized by SGG UCN34 or the closely related non-pathogenic S. gallolyticus subsp. macedonicus (SGM) revealed that 164 proteins and 725 phosphorylation sites were differentially regulated following colonization by SGG UCN34. Ingenuity Pathway Analysis (IPA) indicates a pro-tumoral shift specifically induced following colonization by SGG UCN34, as most proteins and phosphoproteins identified were associated with digestive cancer. Comprehensive analysis of the altered phosphoproteins using ROMA software revealed significantly elevated activities in several cancer hallmark pathways affecting tumoral cells and their microenvironment, i.e. MAPK (ERK, JNK and p38), mTOR and integrin/ILK/actin signaling, in SGG UCN34 colonized colon. Importantly, analysis of protein arrays of human colon tumors colonized with SGG showed up-regulation of PI3K/Akt/mTOR and MAPK pathways, providing clinical relevance to our findings. To test SGG’s capacity to induce pre-cancerous transformation of the murine colonic epithelium, we grew ex vivo organoids which revealed unusual structures with compact morphology following exposure to SGG. Taken together, our results reveal that the oncogenic role of SGG UCN34 is associated with activation of multiple cancer-related signaling pathways
Sherds of societies: Quantitative and petrographic analysis of Neolithic ceramics in Northeast China
No full textInternational audienceIn China, Neolithic sites are routinely attributed to “archaeological cultures” through typological comparisons of complete pottery vessels. However, ceramic datasets have the potential to reveal more than a chrono-cultural attribution. Taking into account not only all the complete vessels but also all the sherds excavated from a site makes it possible to use quantitative analysis as well as morpho-stylistic and petrographic approaches to measure the heterogeneity of the ensemble and ask why and how it was formed. The Wutaishan site in Nong’an, Jilin province, located at the centre of Northeast China, was chosen to implement this methodology. The ceramology research on the complete pottery dataset excavated at this site sheds light on the long- and short-distance exchanges networks in Northeast China at the turn of the 4th millennium BCE, provides a new understanding of inter-site relations in the Yitong River valley, and opens perspectives on the interpretation of the functional spatial layout within the site itself
Fibro-adipogenic progenitors in physiological adipogenesis and intermuscular adipose tissue remodeling
No full textInternational audienceExcessive accumulation of intermuscular adipose tissue (IMAT) is a common pathological feature in various metabolic and health conditions and can cause muscle atrophy, reduced function, inflammation, insulin resistance, cardiovascular issues, and unhealthy aging. Although IMAT results from fat accumulation in muscle, the mechanisms underlying its onset, development, cellular components, and functions remain unclear. IMAT levels are influenced by several factors, such as changes in the tissue environment, muscle type and origin, extent and duration of trauma, and persistent activation of fibro-adipogenic progenitors (FAPs). FAPs are a diverse and transcriptionally heterogeneous population of stromal cells essential for tissue maintenance, neuromuscular stability, and tissue regeneration. However, in cases of chronic inflammation and pathological conditions, FAPs expand and differentiate into adipocytes, resulting in the development of abnormal and ectopic IMAT. This review discusses the role of FAPs in adipogenesis and how they remodel IMAT. It highlights evidence supporting FAPs and FAP-derived adipocytes as constituents of IMAT, emphasizing their significance in adipose tissue maintenance and development, as well as their involvement in metabolic disorders, chronic pathologies and diseases. We also investigated the intricate molecular pathways and cell interactions governing FAP behavior, adipogenesis, and IMAT accumulation in chronic diseases and muscle deconditioning. Finally, we hypothesize that impaired cellular metabolic flexibility in dysfunctional muscles impacts FAPs, leading to IMAT. A deeper understanding of the biology of IMAT accumulation and the mechanisms regulating FAP behavior and fate are essential for the development of new therapeutic strategies for several debilitating conditions
Relating the Hall conductivity to the many-body Chern number using Fermi's Golden rule and Kramers-Kronig relations
No full textInternational audienceThis pedagogical piece provides a surprisingly simple demonstration that the quantized Hall conductivity of correlated insulators is given by the many-body Chern number, a topological invariant defined in the space of twisted boundary conditions. In contrast to conventional proofs, generally based on the Kubo formula, our approach entirely relies on combining Kramers-Kronig relations and Fermi's golden rule within a circular-dichroism framework. This pedagogical derivation illustrates how the Hall conductivity of correlated insulators can be determined by monitoring single-particle excitations upon a circular drive, a conceptually simple picture with direct implications for quantum-engineered systems, where excitation rates can be directly monitored
Restoration of mitochondria cristae in live microscopy images
No full textInternational audienceMitochondria play an essential role in the life cycle of eukaryotic cells. However, we still don't know how their ultrastructure, like the cristae of the inner membrane, dynamically evolves to regulate these fundamental functions, in response to external conditions or during interaction with other cell components. Although high-resolution fluorescent microscopy coupled with recently developed innovative probes can reveal this structural organization, their long-term, fast and live 3D imaging remains challenging. To address this problem, we have developed a convolutional neural network to restore mitochondrial cristae in low spatial resolution microscopy images. Depending on the conditions of use indicated, our method works well on broad microscopy modalities (STED, Live-SR and LLSM). It is ultimately applied in the context of mitochondrial network dynamics during interaction with endo/lysosomes membranes.</div
Brain Charts for the Rhesus Macaque Lifespan
No full textAbstract Recent efforts to chart human brain growth across the lifespan using large-scale MRI data have provided reference standards for human brain development. However, similar models for nonhuman primate (NHP) growth are lacking. The rhesus macaque, a widely used NHP in translational neuroscience due to its similarities in brain anatomy, phylogenetics, cognitive, and social behaviors to humans, serves as an ideal NHP model. This study aimed to create normative growth charts for brain structure across the macaque lifespan, enhancing our understanding of neurodevelopment and aging, and facilitating cross-species translational research. Leveraging data from the PRIMatE Data Exchange (PRIME-DE) and other sources, we aggregated 1,522 MRI scans from 1,024 rhesus macaques. We mapped non-linear developmental trajectories for global and regional brain structural changes in volume, cortical thickness, and surface area over the lifespan. Our findings provided normative charts with centile scores for macaque brain structures and revealed key developmental milestones from prenatal stages to aging, highlighting both species-specific and comparable brain maturation patterns between macaques and humans. The charts offer a valuable resource for future NHP studies, particularly those with small sample sizes. Furthermore, the interactive open resource ( https://interspeciesmap.childmind.org ) supports cross-species comparisons to advance translational neuroscience research