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Chilling injury to algal symbionts induces host starvation and metabolic reorganization in a temperate cnidarian
No full text● Global temperature anomalies increasingly disrupt the cnidarian-algal symbiosis through a phenomenon coined bleaching. In contrast to heat stress, the mechanisms underlying symbiotic breakdown under cold stress remain largely unknown. ● Combining physiological and metabolomic measurements, we investigated the response of the photosymbiotic sea anemone holobiont Aiptasia couchii to an experiment mimicking a cold spell in the Mediterranean Sea. ● Within four weeks, we observed the onset of symbiotic breakdown reflected in reduced algal endosymbiont density and chlorophyll a content. While photosynthetic efficiency remained largely unaffected, no gross photosynthesis was detectable in cold-stressed anemones and decreases in glycosyldiacylglycerols and fatty acyl glycosides indicated chloroplast lipid remobilization. This breakdown of symbiotic carbon cycling was reflected in increased dipeptide and ceramide levels suggesting anemones catabolized protein reserves and induced pre-apoptotic pathways. ● Taken together, these responses suggest a decoupling of light and dark reactions of photosynthesis in cold-stressed endosymbionts, resembling chilling injury in higher plants and free-living microalgae. This chilling-induced collapse of symbiotic nutrient cycling eventually leads to host starvation in cold-stressed Cnidaria. Hence, while cold and heat stress may invoke contrasting physiological effects on endosymbionts, our results suggest that both stressors destabilize the symbiosis through similar mechanisms rooted in host starvation
The emotional turn and the aesthetic challenges of sociological inquiry: Writing emotions in a time of upheaval
No full textInternational audienc
Francis Hallé (1938–2025), founder of the study of tree architecture
No full textInternational audienceFrancis Hallé (1938-2025) was one of the most influential French botanists of the last century. He founded plant architectural analysis, showing that post-embryogenic development follows intrinsic, species-specific rules, and that the immense diversity of tree forms can be captured by a finite set of recurring architectural models. He also co-invented the Radeau des Cimes, a canopy-access platform that transformed tropical forest research by making the canopy directly observable and sampleable, and by catalysing ambitious, multinational expeditions. Beyond research, Hallé was an extraordinary communicator: through books, drawings, and public talks, he fought plant blindness and taught generations to look at plants differently. In his final years, he led a major project with the aim to recreate a large, primary forest in Western Europe. Hallé died on 31 December 2025, leaving a scientific, cultural, and ecological legacy that will long outlive him
A comparative analysis of infection and mortality in reassessing africa’s COVID-19 dynamic using time-varying tests
No full textInternational audienceBackground It is commonly believed that Africa largely evaded the worst of the COVID-19 pandemic, with fewer cases than other continents. However, regional comparisons that ignore differences in testing intensity may misrepresent dynamics. Studying the spread and case-fatality relationship during COVID-19 across WHO regions requires explicitly adjusting for time-varying test volumes. Methods We build a weekly panel dataset spanning May 2020 to December 2021 for the WHO regions: Africa, Eastern Mediterranean, South-East Asia, the Americas, Western Pacific, and Europe. Data on tests, confirmed cases, and COVID-19-attributed deaths were sourced from Our World in Data. We apply a novel metric that corrects for fluctuating test volumes to quantify week-to-week acceleration in infections and in mortality. We then compare the frequency, magnitude, and timing of these acceleration episodes across regions.Results Accounting for testing dynamics, we show that Africa exhibits multiple infectionacceleration episodes whose magnitude and frequency match those in other regions. Mortality accelerations in Africa closely follow infection surges, with an average lag of ten weeks. A positive correlation between infection acceleration in Africa and the Americas further indicates synchrony. These findings hold when using a larger secondary dataset of 140 countries. Conclusions Contrary to prevailing assumptions, Africa was not spared from the pandemic's severe dynamics. Infection surges were on par with those elsewhere and were followed by mortality accelerations. These results underscore that accounting for testing variability is essential to accurately assess pandemic progression, and they highlight the urgent need to strengthen surveillance and healthcare capacity across all regions.The relatively low number of reported COVID-19 cases and deaths in Africa has prompted debates about whether the continent was spared the worst of the pandemic, a phenomenon described by some as the African "puzzle" 1,2 or "paradox" 3 . Early media reports and research articles speculated that Africa's younger population, lower population density in rural areas, and prior experience with infectious diseases and their pharmaceutical treatments might have mitigated the severe impacts observed in other regions.However, emerging evidence from seroprevalence studies indicates that far more individuals in Africa were exposed to SARS-CoV-2 than is reflected in official surveillance data, especially during the pandemic's first 2 years. For example, the ratio of seroprevalence to confirmed cases has been estimated to be as high as 100:1 4 . This gap between seroprevalence estimates and reported cases grew as the pandemic continued 5 , suggesting substantial under-reporting in surveillance data. For example, while 6 mention low testing rates as a likely source of under-reporting in their discussion of the</div
Proteomic Signature in Men with Central Serous Chorioretinopathy
No full textInternational audienceTo explore systemic contributors to central serous chorioretinopathy (CSCR) pathogenesis, we performed untargeted serum proteomics in 60 male CSCR patients (30 acute, 30 chronic) and 60 age-matched controls using label-free LC-MS/MS with stringent statistical pairing. Among 242 abundant proteins identified, 27 (11.5%) were significantly different in CSCR, converging on pathways of complement activation, coagulation, oxidative stress, immune regulation, and response to external stimuli. Complement cascade components (C1QA, C1S, C3, C4B, C8A/B/G, CFB) were upregulated, while the regulators CFHR1 and CFHR2 were decreased, contrary to age-related macular degeneration. Oxidative stress-related proteins (haptoglobin, hemoglobin subunits, peroxiredoxin-2) were elevated, consistent with prior evidence of systemic redox imbalance in CSCR. Tetranectin (CLEC3B) decreased and attractin (ATRN) increased in CSCR were validated by ELISA. Multiplex immunofluorescence on the human retina localized tetranectin to Muller cells, including the outer limiting membrane, and to the RPE and attractin to photoreceptor segments, retinal pigment epithelium, Bruch's membrane, and the choriocapillaris, supporting potential roles of both proteins at the retina-choroid interface. A distinct systemic proteomic signature in patients with CSCR highlights complement dysregulation, oxidative stress, and stress responses to external stimuli and identifies tetranectin and attractin as candidate biomarkers, which should further be validated in other cohorts
Multifunctionality of agroecological vineyards: complex interactions between functional and taxonomic diversity of service crops and ecosystem services
No full textInternational audienceHighlights: • Agroecological practices shaped the taxonomic and functional diversity of service crops. • Service crops improved soil structure and natural enemies' abundance. • Service crops reduced soil fertility and limited grapevine growth and yield. • Adaptive management is needed to limit grapevine–service crop competition.Abstract: Agroecological practices in vineyards can enhance agroecosystems multifunctionality, by reducing pesticides use and their adverse effects on human health and the environment. However, growers remain concerned about potential negative impacts of plant diversification on grapevine performance, and existing literature report conflicting findings. This study employs both taxonomic and functional approaches to characterize weed communities in inter-rows of agroecological vineyards and assesses the effects of different plant diversification strategies-tillage (Tviti), service crop (Aviti), service crops and agroforestry (Dviti)- on soil quality, grapevine performance, and natural regulation processes over a two-year period in the south of France. Management practices shaped weed communities functional traits, with high tillage (Tviti) favoring acquisitive strategies plant communities. Those traits directly affected several of the indicators of services: service crops competed for soil resources, particularly nitrogen, affecting negatively grapevine yield and vigor. However, in 2023, more diverse systems (Aviti, Dviti) exhibited improved soil aggregate stability and increased natural enemy diversity. However, results varied significantly across years, highlighting the importance of environmental factors. Finally, no clear agroforestry effect was observed, likely due to the young age of the trees. A deeper understanding of the relationships between functional diversity and multiple ecosystem services in vineyards could help mitigate potential trade-offs associated with plant diversification. Furthermore, adapting management practices to local abiotic conditions and growers’ requirements is essential for optimizing both vineyard productivity and ecological sustainability
Mitigating half-wave plate systematics at the map-making level: calibration requirements for LiteBIRD
No full textInternational audienceAlthough half-wave plates (HWPs) are becoming a popular choice of polarization modulators for cosmic microwave background (CMB) experiments, their non-idealities can introduce systematic effects that should be carefully characterized and mitigated. One possible mitigation strategy is to incorporate information about the non-idealities at the map-making level, which helps to reduce the HWP-induced distortions of the reconstructed CMB. Nevertheless, the non-idealities can only be known with finite precision. In this paper we investigate the consequences of discrepancies between their true frequency profiles and those assumed by the map-maker. We present an end-to-end framework, including a blind component-separation step, and use it to translate these discrepancies into a bias on the tensor-to-scalar ratio, , for the LiteBIRD satellite mission. We subsequently derive realistic and conservative measurement requirements for accurately characterizing the HWP non-idealities to ensure they do not compromise LiteBIRD's ambitious scientific goals. We find that the obtained results are robust against sky models with varying complexity
Dire ou ne pas dire la situation d’énonciation dans la poésie waka : l’exemple des séries poétiques d’Izumi Shikibu
No full textInternational audienc
Transition 1point5, the platform for French academic research laboratories engaged in their environmental transition
No full textThis article presents an analysis, quantitative and qualitative, of the actions shared by French laboratories on the Transition 1point5 platform. This is an open-source web application, developed by the French research group Labos 1point5, that allows volunteer French laboratories to share the measures -the actions-they have taken to reduce their environmental footprint. We present the analysis of the 274 actions shared by 69 laboratories on the platform on 11 June 2025, addressing the following questions. What measures are research laboratories implementing to adopt sustainable practices? Is there a single transition path that applies to all laboratories? What role do awareness-raising initiatives play in this process? Can participatory workshops add value to the transition process? Have laboratories undergoing transition effectively reduced their GHG (greenhouse gases) emissions?The main result of this study is that, rather than a single transition pathway, the platform's laboratories employ various approaches depending on their specific characteristics. These approaches share common features, such as the use of awareness-raising activities, the creation of working groups dedicated to environmental issues, and increasingly participatory workshops to discuss and implement transition actions. Another key finding is that it is too early to measure the effectiveness of the implemented measures in terms laboratories' GHG (greenhouse gas) reductions, since most of the laboratories only implemented their actions in 2024 or early 2025.Nevertheless, the platform provides valuable insights into how research laboratories are engaging in the transition, revealing organizational processes and demonstrating that another way to do research is explored.Cet article présente une analyse quantitative et qualitative des actions partagées par les laboratoires français sur la plateforme Transition 1point5. Il s'agit d'une application web open source, développée par le GDR Labos 1point5, qui permet aux laboratoires français volontaires de partager les mesures - les actions- qu'ils ont prises pour réduire leur empreinte environnementale. Nous présentons l'analyse des 274 actions partagées par 69 laboratoires sur la plateforme au 11 juin 2025, en abordant les questions suivantes. Quelles mesures les laboratoires de recherche mettent-ils en œuvre pour adopter des pratiques durables ? Existe-t-il une trajectoire de transition unique qui s'applique à tous les laboratoires ? Quel rôle jouent les initiatives de sensibilisation dans ce processus ? Les ateliers participatifs peuvent-ils apporter une valeur ajoutée au processus de transition ? Les laboratoires en transition ont-ils effectivement réduit leurs émissions de GES (gaz à effet de serre) ?Le principal résultat de cette étude est que, plutôt qu'une trajectoire de transition unique, les laboratoires de la plateforme emploient diverses approches en fonction de leurs caractéristiques spécifiques. Ces approches partagent des caractéristiques communes, telles que le recours à des activités de sensibilisation, la création de groupes de travail dédiés aux questions environnementales et des ateliers participatifs pour discuter et mettre en œuvre des actions de transition.Une autre conclusion importante est qu'il est trop tôt pour mesurer l'efficacité des mesures mises en œuvre en termes de réduction des émissions de gaz à effet de serre (GES) des laboratoires, car la plupart d'entre eux n'ont mis en œuvre leurs actions qu'en 2024 ou au début de 2025.Néanmoins, la plateforme fournit des informations importantes sur la manière dont les laboratoires de recherche s'engagent dans la transition, en révélant les processus organisationnels et en démontrant qu'une autre façon de mener des recherches est explorée