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Amaryllidaceae Alkaloids and Phenolic Acids Identification in Leucojum aestivum L. Plant Cultures Exposed to Different Temperature Conditions
No full textInternational audienceAmaryllidaceae alkaloids are of notable pharmacological relevance. For instance, galanthamine is used in the treatment of Alzheimer’s disease, while other alkaloids (lycorine, crinine, etc.) derived from Amaryllidaceae plants are also of great interest because they exhibit antitumour, antiviral, antibacterial, antifungal, antimalarial, analgesic and cytotoxic properties. Phenolic acids comprise a group of natural bioactive substances that have commercial value in the cosmetic, food and medicinal industries due to their antioxidant, anticancer, anti-inflammatory and cardioprotective potential. In the present study, the effect of temperature (15, 20, 25 and 30 °C) on Amaryllidaceae alkaloid and phenolic acid biosynthesis in Leucojum aestivum in vitro plant cultures was investigated. The highest diversity of alkaloids (i.e., galanthamine, crinan-3-ol, demethylmaritidine, crinine, 11-hydroxyvitattine, lycorine, epiisohaemanthamine, chlidanthine) was noted in plants cultured at 30 °C. By contrast, ismine and tazettine were only present in plants cultured at 15 °C. Temperatures of 20 °C and 30 °C were found to stimulate galanthamine accumulation. The highest lycorine content was noted in plants grown at temperatures of 15 and 30 °C, and it was negatively correlated with the expression of the gene that encodes the cytochrome P450 96T (CYP96T) enzyme which catalyses a key step in the biosynthesis of different types of Amaryllidaceae alkaloids. This observation may reflect temperature-induced shifts in metabolic flux among different branches of Amaryllidaceae alkaloid biosynthesis. The observed stimulating effect of a 15 °C temperature on the chlorogenic, caffeic, p-coumaric, sinapic, ferulic and isoferulic acid content was in line with the highest expression of a gene that encodes the tyrosine decarboxylase (TYDC) enzyme, which is involved in plant stress response mechanisms. At 30 °C, however, the highest content of the caffeic, vanillic, p-coumaric and isoferulic acids was noted
The Bootlegger's Choice: Astroturf Groups, Genuine Baptists or Both?
No full textInternational audienceThe Bootleggers and Baptists (B&B) framework contends that enduring regulatory policies emerge when morally motivated actors (Baptists) provide ethical legitimacy, while economically motivated stakeholders (Bootleggers) discreetly support the measures to advance their own interests. Interestingly, this outcome depends on the support of both groups. We extend the public choice B&B theory by showing that Bootleggers can, in some cases, operate without Baptists by using astroturfing—a deceptive practice that simulates grassroots support or public opinion to manipulate perceptions. We identify the conditions—specifically, the absence of genuine Baptists aligned with Bootleggers’ interests and a context dominated by Bootleggers—under which Bootleggers are more likely to fabricate Baptists. Using a transaction cost–inspired framework, we predict that Bootleggers decide whether to ‘make’ an astroturf group or ‘buy’ influence and legitimacy by partnering with genuine Baptists, depending on which arrangement minimizes their transaction costs. We then develop a strategic framework for understanding how Bootleggers tailor astroturfing efforts to manipulate public perception and simulate civic legitimacy
A cooperative learning framework for the integration of metabolomic data from multiple cohorts and common phenotype identification
No full textInternational audienceIntegrating metabolomic data from multiple studies/cohorts could be an efficient strategy to enhance statistical power and identify robust biomarkers. However, challenges associated with batch effects, study-specific biases, and dataset heterogeneity, hinder results reproducibility and translation. Limitations have been reported in shared variable mode data integration approaches, both for early fusion that struggles with inter-study variability, and late fusion that may overlook inter-dataset relationships. Here, we propose a novel cooperative learning framework for metabolomics data integration from multiple studies, designed to improve candidate biomarker discovery by balancing advantages of early and late fusion, while mitigating study-specific confounders. The proposed approach consists in leveraging univariate and multivariate analysis and an optimized loss function. To implement the approach, early-stage integration was based on a multiblock method (MINT-PLS-DA), while separate PLS-DA was used in late fusion. Univariate analysis was performed via a mixed model. The approach was first evaluated in controlled conditions using synthetic data, and then applied to two existing untargeted metabolomics human datasets. Preliminary assessment focused on batch effect reduction across datasets, and agreement between early and late fusion outputs. Using real word data, the results showed that 10% of the initial features were stable across early and late fusion. This showed improved consistency compared to when they were published separately on the integrated dataset. All results demonstrate the ability of the proposed approach to capture the common part of phenotypes. The developed integration model based on cooperative learning leverages the complementary strengths of early and late fusion, offering an efficient solution for metabolomics data integration, enhancing the reliability of potential biomarker discovery
Proteomic analysis of differential biological responses and fatty acid metabolism in slow-growing chickens fed dietary tuna oil directly or via glucose transporter-targeted nanoparticles
No full textInternational audienceThis study investigated the effects of tuna oil (PC) and tuna oil encapsulated in lipid nanoparticles (TNP) on metabolic pathways in thigh muscle of slow-growing chickens using proteomic analysis. Compared with the negative control (NC) diet containing 6% rice bran oil, the PC and TNP diets replaced half of the rice bran oil with tuna oil, thereby increasing dietary n-3 PUFAs and altering the n-6/n-3 ratio. Iliotibialis muscle samples were collected from slow-growing Korat chickens (n = 6 for each PC and TNP; n = 5 for NC). Fatty acid profiles were analyzed by gas chromatography-mass spectrometry following lipid extraction and methylation. Proteomics analysis was performed using polyacrylamide gel-based protein separation and nanoLC-MS/MS to identify and quantify differentially expressed proteins. Distinct biological responses were observed between dietary treatments. In the TNP group, energy metabolism shifted toward aerobic pathways, with increased β-oxidation and reduced reliance on alternative pathways, such as the creatine-phosphate system, to support the tricarboxylic acid cycle. In contrast, the PC group exhibited high lipid peroxidation and by-products, triggering robust antioxidant and detoxification responses, as well as membrane repair mechanisms. Although the TNP group also activated antioxidant defenses, the response was less pronounced and was accompanied by increased expression of proteins involved in vesicle trafficking. Lipid peroxidation in the PC group was associated with calcium influx to maintain calcium homeostasis and stabilize muscle contraction under oxidative stress. This was evidenced by the upregulation of proteins related to sarcoplasmic reticulum calcium pumps and muscle contraction stabilization. Conversely, the TNP group demonstrated adaptive responses to increased contractile activity with lower oxidative burden. Regarding immune function, the PC group showed stronger MHC-based immunosurveillance, reflecting heightened oxidative stress. Although immune responses were less pronounced in the TNP group, immune surveillance was maintained through selective protein expression. Overall, these findings demonstrate distinct cellular strategies in response to oxidative stress and immune challenges between PC and TNP treatments, highlighting the potential of lipid nanoparticle systems to optimize dietary lipid delivery in poultry
Where is sociology headed?
No full textInternational audienceSociology's media success undermines its scientific nature. Yet sociology is based on the methodical application of reason, grounded in methodologically organized observation of the social world. It seeks to “causally explain the social world” (Weber) since “nothing exists without a social reason” (Durkheim). Applying this philosophy of knowledge leads to objectifying the implicit, connecting compartmentalized dimensions, and opposing the derision of reason. However, putting this concept into practice faces many obstacles due to the current rise of assertive anti-rationalism. Scientific autonomy must therefore be defended both against external measures that seek to limit it and against the internal propensity for individualized subjectivism.Le succès médiatique de la sociologie nuit à sa scientificité. Pourtant la sociologie repose sur une application méthodique de la raison basée sur une observation méthodologiquement organisée du monde social. Elle cherche à « expliquer causalement le monde social » (Weber) puisque « rien n’est sans raison d’être sociale » (Durkheim). Appliquer cette philosophie de la connaissance conduit à objectiver l’implicite, à relier des dimensions cloisonnées ; à s’opposer à la dérision de la raison. Reste que la mise en pratique de cette conception se heurte à de nombreux obstacles suscités par l’avancée actuelle d’un antirationalisme affirmé. Il faut donc défendre l’autonomie scientifique aussi bien contre les mesures externes qui visent à la limiter que contre la propension interne aux facilités d’un subjectivisme individualisé
Local Communication in Repeated Games with Local Monitoring
No full textI consider repeated games with local monitoring: each player observes his neighbors' moves only. Hence, monitoring is private and imperfect. I assume local and public communication: communication is restricted to neighbors, and each player sends the same message to each of his neighbors at each stage. Both communication and monitoring structures are given by the network. The solution concept is perfect Bayesian equilibrium. In the four-player case, a folk theorem holds if and only if the network is 2-connected. Some examples are given for games with more than four players
Increasing prevalence of warm monomictic lakes in France over six decades under climate change
No full textInternational audienceThis study utilized temperature simulations from the Ottosson-Kettle-Prats Lake Model and a modified Lewis classification to analyze temporal changes in mixing-regime dynamics, temperature, density gradients, and meteorological indicators in 170 French lakes between 1959 and 1988 and 1989-2019. In the initial period, 55%, 30% and 15% of lakes were classified as warm monomictic, polymictic and dimictic respectively, with 57% of lakes experiencing anomalous regimes. Notably, 6% of the lakes, all at low altitudes (< 800 m a.s.l.) and located in central and north-eastern France shifted from dimictic to warm monomictic between the two periods, representing 77% of all low-altitude dimictic lakes. In 1989-2019, these lakes experienced a warmer climate with annual air temperatures increasing by an average of 0.19 °C/dec across all lakes, with an annual epilimnion warming averaging 0.25 °C/dec compared to 0.2 °C/dec for non-shifting lakes. Additionally, they became more stable and had the greatest density gradient change, averaging 0.07 kg/m³ between 1989 and 2019 and 1959-1988. In contrast, high-altitude lakes remained dimictic, showing an annual epilimnion warming averaging 0.19 °C/dec and a particular winter solar radiation decrease averaging -6.96 W/m 2 /dec in 1989-2019. Further, they did not show significant changes in average density gradients between the two periods. Our findings provide new insights into the mixing-regime dynamics of French lakes over the past six decades. This research is crucial for understanding the ecological impacts of physical alterations and for guiding management strategies under climate change. In the future, we expect less mixing in dimictic lakes, especially those at low altitudes
À quelle fréquence d'images faut-il enregistrer la danse frétillante des abeilles ?
No full textToday, we know how to decode the honey bee dance, but some uncertainties remain, particularly regarding the appropriate capture frequency. The average oscillation frequency of dancing honeybees is close to 13 Hz with a maximum slightly higher than 18 Hz. Several studies using cameras recorded the honey bee waggle dance at conventional framerates of 25 or 30 fps. However, according to Shannon's theorem, the capture frequency should be at least 36 Hz. Our study focused on the analysis and processing of a theoretical signal oscillating at 15 Hz. Our objective is to demonstrate the importance of framerate in optimizing the capture of honey bee dance behavior. We propose several diagrams to illustrate the impact of different framerates, as well as the impact of a phase shift between the oscillation of the dance and the video frames and provide an example of a compatible hardware choice. We also demonstrate the negative impact of low framerates using an automatic honey bee dance analysis script. We can conclude that a framerate of 60 fps is the most appropriate considering current needs and equipment technology.Aujourd'hui, nous savons décoder la danse des abeilles, mais certaines incertitudes persistent, notamment concernant la fréquence de capture optimale. La fréquence d'oscillation moyenne des abeilles dansantes est proche de 13 Hz, avec un maximum légèrement supérieur à 18 Hz. Plusieurs études utilisant des caméras ont enregistré la danse des abeilles à des fréquences d'images conventionnelles de 25 ou 30 images par seconde (ips). Or, selon le théorème de Shannon, la fréquence de capture devrait être d'au moins 36 Hz. Notre étude s'est concentrée sur l'analyse et le traitement d'un signal théorique oscillant à 15 Hz. Notre objectif est de démontrer l'importance de la fréquence d'images pour optimiser la capture du comportement de danse des abeilles. Nous proposons plusieurs schémas pour illustrer l'impact des différentes fréquences d'images, ainsi que l'impact d'un déphasage entre l'oscillation de la danse et les images vidéo, et nous fournissons un exemple de choix de matériel compatible. Nous démontrons également l'impact négatif des faibles fréquences d'images à l'aide d'un script d'analyse automatique de la danse des abeilles. Nous pouvons conclure qu'une fréquence d'images de 60 ips est la plus appropriée compte tenu des besoins actuels et des technologies disponibles
Selenomethionine mitigation of methylmercury-induced epigenetic and transcriptomic alterations in rainbow trout brain: a toxicogenomic survey
No full textInternational audienceMethylmercury (MeHg) is a pervasive neurotoxicant threatening aquatic ecosystems. Selenium (Se) has been reported to protect fish against the adverse MeHg toxicity, yet molecular investigations of their interaction in the brain remain scarce. This study investigated the molecular effects of dietary MeHg and whether organic Se, in the form of selenomethionine (SeMet), could mitigate MeHg-induced change in the brain of rainbow trout (Oncorhynchus mykiss). A 6-month feeding trial was conducted with diets containing low basal Se (0.3 mg/kg) and no mercury (Hg), supplemented with 2 mg Hg/kg diet as MeHg, alone or combined with 1.5 mg Se/kg diet as SeMet. Gene methylation (reduced representation bisulfite sequencing) and expression (RNA sequencing) were assessed, alongside biochemical quantification of DNA methylation-related metabolites (S-adenosylmethionine, SAM, and S-adenosylhomocysteine, SAH) and oxidative stress-related metabolites (reduced glutathione, GSH, and oxidized glutathione, GSSG). SeMet did not prevent MeHg-induced changes in SAM/SAH levels but mitigated MeHginduced alterations in DNA methylation of genes related to the glutamatergic system, inflammation, and immune response. Transcriptomic analysis revealed antagonistic effects of MeHg and SeMet on energy metabolism pathways, with hypoxia-inducible factor 1 subunit alpha-like 2 identified as a potential key regulator. Although this molecular interaction may reflect SeMet-mediated attenuation of oxidative stress, biochemical data did not confirm changes in GSH/GSSG levels. These findings provide novel insights into the molecular mechanisms underlying MeHg neurotoxicity and its modulation by SeMet in fish brain, highlighting a potential protective role of organic Se against MeHg-induced molecular alterations
Behavioral and functional responses of Hormogaster samnitica to different organic amendments
No full textInternational audienceThe decline of soil organic matter in Mediterranean agroecosystems, coupled with the underutilization of crop residues, calls for sustainable strategies that enhance soil health while valorizing local organic resources. This study investigates the behavioral and functional responses of Hormogaster samnitica, a large-bodied, endogeic earthworm, to four organic amendments derived from agricultural residues: vine pruning compost (PRUN), vine pruning compost with a commercial accelerator (COMM), vine pruning compost inoculated with Indigenous Microorganisms (INDG), and vermicompost from spent coffee grounds (VERM). The experiment was conducted in laboratory mesocosms using repacked soil columns. Earthworms were introduced at three body size classes (“big”, “medium” and “small”), and their impact on soil porosity and infiltration was assessed via X-ray tomography and infiltration tests. Results showed that body size significantly affected earthworm activity, with larger individuals creating wider and deeper burrows and markedly increasing water infiltration. Among treatments, COMM significantly enhanced macroporosity in the amended soil layer and induced a marked shift in the vertical distribution of macropores. However, despite increased porosity, compost-based amendments generally reduced infiltration rates compared to the CTRL. VERM showed limited effects on both bioturbation and infiltration. A two-choice preference test revealed that H. samnitica exhibited weak substrate preferences, while the more generalist Aporrectodea caliginosa clearly favored compost-based treatments over VERM and CTRL. Overall, these findings highlight the importance of considering species-specific traits and amendment properties when evaluating the ecological impact of organic inputs, and support the use of compost as a biostimulant for soil fauna and structure enhancement in Mediterranean systems