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Mutation of Brain Aromatase Impairs Behavior and Neuroplasticity in Adult Zebrafish
No full textInternational audienceBrain aromatase, an enzyme responsible for the local synthesis of estrogens, plays a key role in regulating behavior and neuroplasticity in mammals. In teleost fish, brain aromatase is encoded by the cyp19a1b gene, which is strongly expressed in radial glial cells; however, the specific functions of this enzyme are currently unknown. To investigate its role, a cyp19a1b‐mutant zebrafish line was generated using gene‐editing techniques. Behavioral, neurogenic, and neurotransmission‐related parameters were assessed in adult male and female zebrafish. Behavioral analysis highlighted significant alterations in mutant zebrafish, including changes in swimming activity, boldness, sociability, and aggression, with a stronger effect in males compared to females. Beyond these behavioral modifications, mutant zebrafish exhibited disrupted cell proliferation patterns, as assessed by PCNA immunofluorescence in key forebrain regions. Specifically, proliferation decreased in the telencephalon and in the caudal hypothalamus of mutant zebrafish while increasing in the olfactory bulbs. The number of dopaminergic and serotonergic neurons, visualized by immunofluorescence, remained unchanged. Similarly, HPLC‐ED quantification of monoamines and their metabolites showed no significant differences between mutant and wild‐type zebrafish. To further explore the impact of the cyp19a1b mutation on gene expression, transcriptomic analysis was performed using BRB‐Seq technology. Gene expression analyses identified several processes affected by the mutation, including cell proliferation, apoptosis, estrogen signaling, neuroplasticity, and behavioral regulation, in a sex‐ and region‐dependent manner. In conclusion, our results demonstrate that several behaviors, including locomotor activity, sociability, aggressiveness, and anxiety, exhibit marked sexual dimorphism. They show that the cyp19a1b mutation affects locomotor activity in a context‐dependent manner, increases boldness, and reduces aggressiveness. In addition, transcriptomic analyses revealed widespread dysregulation of gene expression, which likely contributes to the observed behavioral alterations. Taken together, these findings underscore the crucial role of brain aromatase in the neurobiological regulation of diverse behaviors
VIGIA-PlumeNet and VIGIA-PlumeData: Open-Source AI Segmenting Model and Database For Volcanic Plumes and Emissions From Optical Cameras
No full textInternational audienceContinuous monitoring of volcanoes is essential for advancing scientific understanding and issuing alerts to at-risk populations. Many volcanoes are equipped with ground-based RGB cameras, whose recordings are analyzed by experts or semi-automatic models. Distinguishing clouds from volcanic columns and other emissions automatically remains a major challenge. To date, no open-source labeled database of volcanic images exists, and no study has attempted to localize multiple emissions beyond ash columns. We introduce VIGIA-PlumeNet, capable of operating across diverse environments and sky conditions. It performs multi-class segmentation, identifying the volcano and distinguishing plumes, gases, and lava, with 91% accuracy. This is enabled by leveraging the DINO-v2 foundation model as encoder, combined with a segmentation head fine-tuned for our task; and constructing VIGIA-PlumeData, a dataset of 250 manually annotated images from over 60 volcanoes worldwide, collected through community effort. VIGIA-PlumeData and VIGIA-PlumeNet are released publicly, establishing the first benchmark dataset for volcanic image segmentation
Dynamic in situ analysis of modern and ancient flax yarns: Impact of microstructure and aging
No full textInternational audienceFlax yarns are widely used in composites and textiles, yet their mechanical performance is limited by factors like microstructure and durability, necessitating in-depth investigation of their tensile behavior. This study aimed to evaluate the dynamic response of flax yarns under tensile loading, using in situ SEM tensile testing to reveal realtime failure mechanisms and microstructural behavior. Novelty lies in the unprecedented examination of 4,000year-old Egyptian yarns, offering unique insights into the effects of aging on fiber morphology and strength. This research included single and ply yarns from modern Egypt, France, and ancient Egypt. Findings indicate significant strength differences due to strong morphological variations. Morphological analysis demonstrates that, with aging, ancient yarns exhibit greater number of kink bands and fiber separation, indicating structural weakening and compound middle lamella (CML) degradation. Failure analysis revealed fiber breakage is the primary failure mode in modern yarns, contrasting with combined breakage and slippage in ancient yarns, indicating distinct degradation mechanisms. Kink-bands were identified as critical to tensile behavior, initiating cracks that propagate, causing fiber rupture and subsequent breakage in bundles within yarns. These results highlight the evolution in yarn production and durability, emphasizing the impact of fiber microstructure and aging on performance, contributing essential insights for advancing the mechanical performance of flax-based materials
Unifying self-organization and evolution principles in material and biological discrete systems
No full textInternational audienceThe post-Darwinian era has been marked by a long-term effort to lay the foundations for a generalized theory of evolution in the broad sense. We suggest throughout this article that most of biological systems, including living species, could stand as multiscale complex systems due to microscopic or mesoscopic properties of the entity interacting with its environment. Intriguing commonalties which exist between the living and non-living species as complex systems give a strong hint that a unified approach could be developed. The paper explores this hypothesis by analyzing how complex systems, such as granular matter, evolve and adapt when brought out of equilibrium. The inherent disorder in most of granular materials gives way to a wide spectrum of structural patterns that can transform according to the external conditions applied. When brought out of equilibrium, phase transitions can occur spontaneously, leading to profound configurational reorganizations where new and unexpected structures can emerge. Using most of the fundamentals derived for granular systems, a material approach of evolution is proposed, whereby living and non-living architectures can be brought together within a rational framework whereby key concepts such as self-organization, emergence, scale effects, fluctuations and memory storage are at the very forefront
Use of anthropogenic debris as nesting materials in a south-Mediterranean yellow-legged gull (Larus michahellis) breeding colony in relation to their environmental availability
No full textInternational audienceThe use of plastics and other anthropogenic debris (AD) as nesting materials by the yellow-legged gull Larus michahellis (YLG) has been previously reported in different north Mediterranean and Atlantic breeding colonies. This behavior is also suspected to widely occur in south-Mediterranean areas, and possibly to a greater extent because of high AD availability related to inefficient waste management systems, but data are lacking. The aim of our study was therefore to investigate AD incorporation into YLG nests in a southern Tunisian breeding colony and determine to what degree this integration was associated with debris availability in the environment. We examined nest materials from 232 nests and evaluated AD pollution within the colony area using transect sampling. Eighty-eight percent of sampled nests contained AD which accounted for 3% of the weight of nest materials. Although plastics were the most common AD category, representing 78% of recorded AD items and 71% of AD weight, there was no evidence of a preference for plastics over the other categories. Indeed, AD of different categories were incorporated into nests in accordance with their availability in the surroundings. However, our results did suggest a preference towards white-clear AD, a pattern that could be driven by the probable dietary origin of these materials. Overall, we report a level of AD in YLG nests that is among the highest found in the Mediterranean, and we suggest that the YLG may be a facilitator of Mediterranean coastal pollution by carrying human waste elements into natural areas
Growth–survival trade‐off in temperate trees is weak and restricted to late‐successional stages
No full textInternational audienceLife-history strategies emerge from eco-evolutionary constraints, where organisms allocate limited resources to growth, survival, and reproduction, resulting in trade-offs such as the growth-survival trade-off. There is still a limited understanding of whether and how disturbance regimes and successional stages might mediate such trade-offs, with potential consequences for species population dynamics and community assembly.2. Here, we investigate how disturbances shape the growth-survival trade-off by comparing early and late-successional forest stands across the eastern United States. Using large-scale sampling to capture the realised niche of 68 temperate species, we estimated species-specific mortality probabilities under zero growth (a proxy for resource-poor environments) applying a Bayesian multilevel modelling framework. We tested trade-offs between these estimates and species' maximum growth capacity (a proxy for resource-rich environments), within and across early and late-successional stands.3. Overall, we found a weak growth-survival trade-off among temperate tree species (R 2 = 0.07). No clear evidence of this trade-off was found in early successional stands (R 2 = 0.02), while late-successional stands showed a relatively strongerthough still weak-positive association between species' maximum growth and mortality under zero growth conditions (R 2 = 0.17). Disturbances therefore seem to conduct data analyses are publicly available at</p
Copepod‐associated microbial biogeography in the epipelagic ocean
No full textInternational audienceAbstract Zooplankton‐microbial interactions play crucial roles in epipelagic ecosystem functions. The distinct west‐to‐east gradients and complex circulation patterns in the Mediterranean Sea, combined with the ubiquity of pelagic copepods, provide an ideal model to study the ecological processes driving host‐associated microbial spatial distribution. Here, we characterized and compared the copepod‐associated microbial metacommunities (CAMC) with those from seawater microbial metacommunities (SMC). Copepod‐associated microbial metacommunities displayed spatial dissimilarity between the western and eastern basins, while SMC exhibited similar microbial compositions. The within‐basin similarity observed in CAMC was associated with connectivity by the surface currents. Ecological drift explained most of CAMC variability, likely as a response to the restricted co‐dispersal of the hosts with their microbes, which presented low prevalence and abundance. Seawater microbial metacommunities displayed higher homogenizing dispersal, with widely distributed generalist taxa. We conclude that CAMC better reflect cross‐basin gradients and connectivity patterns than SMC, suggesting that CAMC may serve as a useful proxy for studying microbial biogeography
forcis: An R package for accessing, handling and analysing the FORCIS database
No full textInternational audienc
Guide méthodologique pour la planification territoriale participative
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/614997/) * Autres projets (id;sigle;titre): ;PACTE;(TUN) Programme d’adaptation au changement climatique des territoires vulnérables de Tunisie// * Collectivites auteurs : CIRAD-ES-UMR TETIS - FRA// CIRAD-ES-UMR G-EAU - FRA// INRAE - FRA//International audienceCe guide traite de planification territoriale, un processus stratégique et décisionnel visant à organiser et à programmer le développement d'un territoire en intégrant divers aspects tels que l'utilisation des terres, la gestion des ressources naturelles, l'accès aux biens et aux services publics, les infrastructures et les activités économiques. Il est issu de réflexions et d'expérimentations menées en Tunisie depuis plus de quinze ans par le Ministère de l'Agriculture, des Ressources Hydrauliques et de la Pêche et ses partenaires de l'enseignement supérieur et de la recherche agronomique tunisiens et français
The PeatPic project: predicting plot-scale green leaf phenology across peatlands
No full textInternational audienceAbstract Peatlands store approximately one-third of the world’s soil carbon (C), but their functioning is highly variable at fine spatial scales due to differences in vegetation cover and environmental conditions such as water table depth. This fine-scale heterogeneity plays a key role in carbon dynamics yet capturing it—particularly in relation to green leaf phenology (GLP)—is challenging with traditional remote sensing methods. To address this, we developed a smartphone-based methodology and community-science project called the PeatPic Project. We gathered over 3700 photographs from 27 sites across 10 countries in 2021 and 2022, representing different peatland types (bog, fen, and swamp), at 1–2 week intervals. We calculated GLP metrics, such as the data of the start of the season and end of the season, based on the red-blue-green bands from these photographs. We found that GLP metrics varied significantly across peatland types and dominant vegetation communities. Notably, peak greenness at bog sites occurring approximately 10 days later in the year compared to fen sites. Furthermore, variables relation to peatland/vegetation type and energy balance were key predictors of peatland GLP. The PeatPic Project’s readily available methodology offers low-cost opportunities for further research into peatland phenology, enabling the calculation of additional phenological indices and integration with other data types. By refining our understanding of peatland GLP, we can improve predictive C modelling and better assess the impacts of future changes on these important ecosystems