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Environnement et mode d'occupation du sol dans la vallée du Loir au cours de la protohistoire Rapport de prospection thématique - campagne 2023
No full textEvolution of CYP71D drives the diversification of monoterpene indole alkaloid biosynthesis in Gentianales
No full textInternational audienc
Chickens perceive humans as social buffers and might follow human-given cues
No full textInternational audiencePositive perception of humans, extensively documented in domestic mammals, remains underexplored in domestic birds like chickens, where research has mainly focused on fear reduction. This exploratory study evaluated whether chickens perceive humans positively, considering interaction types and breed differences. Two breeds of laying hens (Lohmann LSL Classic and Lohmann Brown Classic) were subjected to one of three human contact treatments over a 13-day period (Days 35–51): physical contact (PC; 1–2 min/day), visual-only contact (VC; 1–2 min/day), or minimal human contact (MC). Following this period, birds underwent several behavioral assessments. In the separation–reunion test (Days 52–53), each bird experienced two consecutive 3-minute phases: separation (experimenter absent) and reunion (experimenter present) in an open-field environment. Calm behaviors (e.g., foraging, non-vigilance) were similar across groups during separation phases but significantly increased in PC birds during reunion phases compared to VC and MC birds. Brown birds exhibited lower calmness during separations compared to reunions—unlike White birds—and spent more time near the experimenter. The capture test consisted of up to six standardized attempts by the experimenter to catch each bird. PC birds were the easiest to capture, MC birds the most challenging, and VC birds displayed intermediate responses. Brown birds were generally easier to capture than White birds. In the local enhancement test (Days 120–137), birds' ability to interpret human gestures to locate food was evaluated. Two PC birds (one White and one Brown) successfully utilized human cues, with Brown PC birds performing notably better overall. These results suggest that chickens exposed to positive human interactions perceive humans positively and may associate human cues with rewards. Although fundamental, this study highlights the potential of breed-sensitive approaches to improve poultry welfare and opens the discussion on adapting human–animal interactions to breed-specific characteristics
Ecosystem Services provided by streams to adjacent agricultural terrestrial ecosystems
No full textInternational audienceStreams are traditionally viewed as receptacles rather than sources of energy with regard to nutrient and energy cycles. For a long time, terrestrial-aquatic interactions have focused on studying the impact of terrestrial ecosystems on aquatic ecosystems, but more and more studies are highlighting the role of aquatic ecosystems on terrestrial ecosystems. Numerous studies have shown that freshwater ecosystems are an important source of energy for the terrestrial environment, mainly through the emergence of winged aquatic insects, recognized as providing nutritional subsidies to terrestrial consumers. They represent a substantial source of fertilization for soils and an important resource for terrestrial organisms. Plants near wetlands where food webs contain fewer insect predators or flying insects receive more pollinator visits and are less pollen limited. Thus, dense hydrographic networks could suggest a strong impact in terms of ecosystem services in adjacent terrestrial ecosystems. The objective of our project is to evaluate three ecosystem services provided by aquatic insects in adjacent agricultural environments following a gradient of agricultural intensification and to analyze their impacts in terms of integration in the management policies of the territories. Five sites located along a gradient of agricultural intensification and in different agricultural contexts where agricultural practices are informed, were selected within three Zones Ateliers from the French Long Term Socio-Ecological Research network. On each site, a headwater stream and its adjacent landscape (1 Km²) will be monitored at the same time (spring and summer) with 13 protocols. The first work package focuses on three ecosystem services provided and mediated by emerging aquatic insects (soil fertilization, pollination and crop pest control). These ecosystem services cannot be studied without an accurate quantification of biodiversity of streams (i.e. emerging aquatic insects and aquatic vegetation), riparian habitats (floral diversity, emerging aquatic insects and terrestrial predators), adjacent agricultural areas (i.e. emerging aquatic insects, terrestrial predators and type of crops) and the quantification of biological flux between aquatic and terrestrial environment. The second WP focuses on the governance of riparian areas. Its objective is to study the history of the governance of French riparian areas, to examine current management practices and their associated representations. This WP will also address recent improvements in the governance of these areas and aims to increase the adoption of ecologically responsible practices by stakeholders. The last WP aims to map Essential Biodiversity Variables (EBVs) of streams and floodplains with high-resolution data and remote sensing techniques and artificial intelligence modelling approach to estimate the respective contribution of various drivers (e.g. landscape features and their arrangement including 3D modelling) . This information is crucial for understanding and linking WP1 and WP2 (i.e. explaining ecosystem services distribution in relation with anthropogenic practices and land uses). Preliminary results suggested a possible important role of aquatic insects in fertilization but a relatively small contribution to direct pollination. We have also highlighted a succession of major changes in river management over the last 100 years, which have profoundly altered the functioning of aquatic ecosystems. However, headwater and riparian habitats are rarely considered in social sciences and limit our ability to integrate their specificities or to mitigate conflicts among users and managers. Ongoing research based a previous discussions with stakeholders, has highlighted that our project should help us to better quantify, in a spatially explicit manner, the relative contribution of freshwaters to ecosystem services in agricultural landscapes, and to better identify leverage points for integrating our results into agricultural practices and environmental management
Doctrine – Adapter la procédure d'expulsion : nécessité ou aberration ?
No full textInternational audienc
Mathematical modelling of the contribution of senescent fibroblasts to basement membrane digestion during carcinoma invasion
No full textSenescent cells have been recognized to play major roles in tumor progression and are nowadays included in the hallmarks of cancer.Our work aims to develop a mathematical model capable of capturing a pro-invasion effect of senescent fibroblasts located in the conjunctive tissue. We focus in the present article on the first moments of the invasion cascade. Considering a localized epithelial tumor, we model the digestion of the collagen fibers of the basement membrane by the proteolytic enzyme MMP-2. The activation of MMP-2 is modelled in detail, as MT1-MMPs bound to the surface of tumor cells interact with proMMPs and TIMPs, proteins enriched in the secretome of senescent Cancer-Associated Fibroblasts, along with its inhibition by TIMPs. Using numerical simulations of the model, calibrated via an extensive literature search, reproducing biologically relevant scenarios, we test the model’s suitability to investigate the effect on basement membrane digestion of fibroblasts presenting a senescence-associated secretory phenotype. Via model reduction, steady state and global sensitivity analyses, we identify the most influential parameters in view of their calibration with empirical data. We conclude the paper discussing mathematical and interdisciplinary perspectives
Fusion Protein‐Assisted Crystallization of Human SUMO1
No full textInternational audienceABSTRACT In this study, we employed a fusion protein‐assisted approach to crystallize human SUMO1, an essential covalent protein modifier that also interacts noncovalently with specific linear protein motifs called SUMO‐interacting motifs (SIMs). SUMO1 has been crystallized previously as part of various complexes but never in isolation. Our strategy involved fusing a variant of a known crystallization facilitator, the TELSAM domain, upstream of the folded part of the SUMO1 protein (residues 18–97). Following a simple purification strategy, we obtained a 2.05‐Å crystal structure of apo TELSAM‐SUMO1, with three distinct SUMO1 chains per asymmetric unit, two of which have an accessible pocket for binding to a SIM. The crystal structure is composed of the expected left‐handed helical filaments formed by TELSAM domains, with protruding SUMO1 molecules mediating connections within and between these filaments to stabilize a three‐dimensional lattice. Since the TELSAM fusion does not affect the SUMO:SIM interaction, as confirmed in solution, our construct may potentially be used to structurally characterize complexes formed between SUMO and SIM‐containing peptides. Neither does the TELSAM fusion interfere with the attachment of SUMO1 to substrates, potentially allowing for the creation of SUMOylated protein forms with improved crystallizability. The study represents a novel application of TELSAM‐assisted crystallization to a small protein of major biological relevance
Genome mining and chemistry-driven discovery of a cell wall lipopeptide signature for Mycobacterium avium ssp. paratuberculosis ancestral lineage
No full textInternational audienceMycobacterium avium subsp. paratuberculosis (Map) causes Johne’s disease (JD), a chronic infection responsible for considerable economic losses to dairy industries worldwide. Genetically clonal, Map has evolved into three distinct genetic lineages designated CII, for bovine strains, SI and SIII, for ovine strains. Previous studies have established that Map does not produce glycopeptidolipids, characteristic of the cell wall surface of mycobacteria belonging to the M. avium complex, but rather sugar-free lipopeptide compounds synthesized by non ribosomal peptide synthetases. In this study, we combined genomic, machine learning, (bio)chemical, and analytical approaches to identify the metabolites biosynthesized by NRPS in the most ancestral SI strains of Map. We have thus characterized a lipotripeptide (L3P-2) signature for the SI genetic lineage, demonstrating that the evolution of this Map subspecies has been accompanied by a diversification of the cell wall lipopeptides. Finally, L3P-2 shows promise for improved serological diagnosis of JD
Black holes with electroweak hair -- the detailed derivation
No full textInternational audienceWe present a very detailed derivation of solutions describing hairy black holes within the gravity-coupled Weinberg-Salam theory, which were previously reported in \href{https://doi.org/10.1103/PhysRevLett.133.171402}{Phys.Rev.Lett. 133 (2024) 171402}. These black holes support a strong magnetic field that polarizes the electroweak vacuum and creates a condensate of massive fields carrying superconducting currents along the black hole horizon. The currents, in turn, generate a ``corona'' of magnetic vortex segments attached to the horizon at both ends. The condensate and corona together constitute the black hole hair. The extremal solutions approach, in the far field, the magnetic Reissner-Nordström configuration, with a total mass that is {\it lower} than the total charge, , due to the negative Zeeman energy of the condensate. This makes the removal of the hair energetically unfavorable. The maximally hairy black holes exhibit masses comparable to terrestrial values, with approximately 11% of their total mass stored in the hair. Given that these solutions arise within a well-tested theoretical framework, they are likely to have physical relevance
