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An innovative analytical approach for a comprehensive overview of internal exposure to pesticides
No full textPlant protection products used in agriculture contain molecules specifically designed to be toxic to target organisms. However, their use can also have unintended effects, posing potential risks to ecosystems and non-target organisms, including humans. Research has deepened our understanding of the links between exposure to these substances and the effects observed in the environment. In particular, studies have highlighted how even low levels of exposure can cause chronic effects on non-target organisms and disrupt ecosystems. These findings underscore the importance of quantifying and characterising these exposures in order to better assess their potential impacts on human health and the environment.International audienceHuman exposure to contaminants, including pesticides, is generally estimated using indirect methods. Conventional biomonitoring methods remain focused on a limited number of known substances, leaving the risks associated with multiple exposures currently underexplored.We propose an innovative approach to detect as many pesticide exposure markers as possible in an untargeted manner by combining three complementary mass spectrometry platforms coupled with chromatography. This approach, based on the exposome concept (Wild, David), allows us to produce exposure data on a wide range of pesticides and metabolites by screening a broad panel of exposure markers. The results demonstrate the added value of this approach, applied to two epidemiological studies (PELAGIE and Nutrinet-Santé), to test for associations with health parameters.</p
Seasonal hazard-vulnerability patterns between drought and wildfire in New Caledonia derived from remote sensing products
No full textInternational audienceClimate change is escalating the frequency and intensity of droughts and wildfires globally. In New Caledonia, future intensification is projected, yet the seasonal and directional temporal relationships between vegetation drought and wildfire activity remain insufficiently characterized at the regional scale. This study presents a regional case study combining remote sensing and in-situ datasets spanning 2000-2024, aggregated at monthly and municipal scales, to analyse drought-fire temporal interactions in New Caledonia. The approach quantifies the temporal sequencing of interactions between vegetation condition and burned area occurrence, distinguishing periods when vegetation stress precedes fire activity (fire hazard) from periods when fire occurrence is followed by altered vegetation conditions (post-fire vulnerability and potential feedbacks). Lagged and seasonal correlation analyses were conducted using the Vegetation Health Index (VHI) as a proxy of vegetation drought and the Burned areas Anomaly Index (BAI) to characterize wildfire activity. Results reveal robust and spatially coherent correlations between vegetation drought and burned area extent, highlighting the strong association between VHI and subsequent wildfire activity. Distinct seasonal interaction patterns emerge, with vegetation condition preceding fire activity during the early dry season (August-September), while fire occurrence is followed by modified surface conditions over subsequent months (November-May), consistent with postfire ecosystem vulnerability and feedback mechanism. Marked geographic contrasts are observed, particularly between the west and east coasts. These findings improve understanding of drought-fire temporal linkages in New Caledonia and provide actionable, region-specific insights for seasonally targeted and spatially explicit wildfire risk management
The role of spermidine in plants and humans: a pathway from climate change adaptation to health benefits
No full textInternational audienceAbstract Growing demands for healthier diets are driving agricultural and food scientists to develop climate-resilient crops and food systems that ensure nutritionally effective food. Beyond providing basic energy requirements, nutrients may actively influence human physiology and health. One such molecule, spermidine, a polyamine abundant in wheat and soybean, has attracted particular interest. From the aspect of human health, spermidine is mainly studied for healthy ageing properties and has been associated with cardioprotective, neuroprotective, and anti-cancerogenic effects. On the other hand, being present in all plants, spermidine is essential for growth, development, and stress adaptation. Endogenously or when exogenously applied, spermidine can help plants adapt to harsh climate change conditions. Bringing together current knowledge on the significance of spermidine in both plants and humans, this review aims to trace its journey From Farm to Pharm , highlighting its importance for sustainable crop production, improved nutrition, and emerging pharmacological applications
The Southern Ocean’s bioluminescent environment revealed by deep-diving Southern elephant seals
No full textInternational audienc
The sodium leak channel NALCN in Drd2+ striatal neurons regulates neuronal excitability, locomotion and food-seeking in a sex-dependent manner
No full textInternational audienceThe sodium leak channel NALCN is an important modulator of cell excitability. Studies so far demonstrated the critical role of this highly conserved channel in the generation and maintenance of pacemaker activity in cells with spontaneous firing, such as cardiomyocytes, adrenal cells, or neurons. However, the physiological importance of NALCN for neurons with no spontaneous firing has been largely overlooked and remains unknown. Yet, Drd2-expressing striatal projection neurons (SPNs) show an enriched expression of NALCN while they are highly hyperpolarized neurons. Considering that pathogenic variants of NALCN in human result in severe pathological conditions with symptoms that include cognitive and motor impairments, we hypothesized that NALCN in Drd2-SPNs was necessary for their correct signal integration and consequently striatal-associated behaviors. Here, we investigated the impact of NALCN deletion in Drd2-SPNs in both male and female mice. Unexpectedly, we found that only male mice with deletion of NALCN in Drd2-expressing neurons exhibited enhanced locomotor responses to novel environment and reduced motivation in food-seeking tasks, while female mice were unaffected in their behavior. Similarly, electrophysiological recordings of SPNs revealed significant sex differences, with male SPNs lacking NALCN exhibiting altered membrane properties and increased excitability, while females showed only subtle changes. Finally, we found that eticlopride-induced catalepsy and signaling events were differently altered by NALCN deletion in Drd2-SPNs male and female mice. This work constitutes the first evidence that NALCN in Drd2-SPNs participates to striatal function and may be a key modulator of response to antidopaminergic treatments, with significant sex differences
Flexitarisme: Définition
No full textInternational audienceComposed of the words “flexible” and “vegetarianism”, flexitarianism refers to a flexible dietary approach which aims to reduce the consumption of animal flesh without excluding it entirely. The adoption of this diet is driven by a variety of motivations: economic, health-related, environmental, or ethical. It can be a way to spend less, to take care of one’s health, to help counteract climate change, or to promote animal welfare.Composé des mots « flexible » et « végétarisme », le flexitarisme est un anglicisme qui désigne une approche alimentaire souple, réduisant la consommation de chair animale sans l’exclure totalement. L’adoption de ce régime est guidée par des motivations variées : économiques, sanitaires, environnementales ou éthiques. Il peut s’agir de dépenser moins, de préserver sa santé, de contribuer à la lutte contre le changement climatique ou de promouvoir le bien-être animal
Two anchoring proteins control daughter apical complex assembly in Toxoplasma gondii
No full textDuring Toxoplasma gondii division, the apical complex—comprising the conoid, apical polar ring (APR), and preconoidal rings—assembles with precise spatiotemporal coordination to form functional daughter buds. Despite their essential roles in invasion, motility, and division, the scaffolding proteins orchestrating this ordered assembly have remained largely unidentified. Here, we identify and characterize RCC1-2 and APR8 as essential factors directing distinct, sequential phases of daughter cell apical complex construction. Both proteins are recruited with precise spatial and temporal dynamics to the daughter buds, where they function as scaffolds rather than static structural components. APR8 transiently occupies the basal region of the APR specifically in early daughter cells. It is dispensable for conoid and PCR initiation, yet its loss causes APR collapse, abolishes SPMT anchoring, and eventually arrests conoid maturation. In contrast, RCC1-2 localizes beneath the APR basal layer and persists throughout daughter cell development, where it contributes to stabilizing the attachment of SPMTs to the APR. Notably, in situ cryo-electron tomography further reveals that the interspersed pillars bridging SPMTs ends to the APR fail to form properly in RCC1-2-depleted parasites. These findings map a hierarchical RCC1-2/APR8-dependent scaffolding process that advances our understanding of parasite replication
Gaussian-like fixed point and variational properties of integral discriminants
No full textInternational audienceWe consider partition functions Z(g) = exp (-g(x))dx where g is a nonnegative polynomial action (a degree-2n form) vanishing only at the origin. Such integrals, known as integral discriminants, appear in statistical mechanics, quantum field theory, and the theory of exponential families. We show that the associated Boltzmann measure dµ = exp(-g(x))dx satisfies a fixed-point property identity relating in a simple manner its degree-2n moments to the coefficients of g. This generalizes familiar identities for the exponential distribution (degree-1) on the positive orthant and the Gaussian measure (degree-2). We further show that g is characterized by three variational principles, including a maximum-entropy principle under scaled moments constraints, extending the Gaussian extremality principle to arbitrary even-degree homogeneous actions. Exploiting these identities in a truncatedmoment numerical scheme (known as the Moment-SOS hierarchy), strengthens the standard semidefinite relaxations, and results in a much faster convergence, thus allowing more efficient approximations of the partition function Z(g) as well as moments of µ
Effet des antibiotiques sur la virulence et l'émergence des mécanismes de résistance chez les Enterobacterales
No full textI. Effet d'une antibiothérapie sur des souches d'Escherichia coli adhérentes et invasives isolées de patients atteints de la maladie de Crohn 37-47 A. Données bibliographiques 37-40 B. Projet 40-47 II. Évaluation de l'activité de l'amikacine sur des souches d'Enterobacterales productrices d'AAC(6')-Ib 48-53 A. Données bibliographiques 48-49 B. Projet 49-53 III. Emergence de résistance par efflux ou imperméabilité chez K. pneumoniae 54-57 A.</div
Co-circulation and co-infection: parasite interactions across scales
No full textInternational audienceParasite–parasite interactions occur both within and between hosts, but the two scales are rarely considered together. Consequently, there is a gap in our ability to predict the integrated effects of interactions occurring across scales, disentangle their relative contributions to key ecological outcomes, and accurately identify the drivers of host–parasite evolutionary responses. Here, we extend the standard susceptible–infected framework of theoretical epidemiology to explicitly incorporate parasite–parasite interactions across scales. We identify where – in each step of the transmission process – such interactions may occur, at the within- or between-host levels, providing empirical examples where possible. Thus, we demonstrate how integrating the two scales provides a more complete understanding of the evolutionary ecology of multi-parasite systems and suggest future avenues of investigation