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Reverse chemical ecology to study the defense of the plant host Sextonia rubra and the chemical mediators of its endophyte Fusarium falciforme against phytopathogen Trametes versicolor
No full textInternational audienceSextonia rubra is a tropical tree endemic to the Guiana Shield and the Brazilian Amazon. Despite its renowned wood durability, it remains susceptible to degradation by white-rot fungi such as Trametes versicolor. To mitigate biotic stresses, plants can rely on their associated microbial communities, including endophytes, which play a crucial role in their defense mechanisms. In this study, we explored the cultivable microbiota of S. rubra, considering it a holobiont.Endophytic strains were isolated from the bark, sapwood and heartwood of S. rubra, and metabolome were extracted. We used a reverse chemical ecology approach to elucidate the mechanisms underlying these extracts' fungicidal activity. In this context, glutathione-S-transferases (GST), key detoxification enzymes of the lignivorous fungus T. versicolor, were chosen as targets. GST tests confirmed the presence of antifungal compounds in extracts from 13 of the 152 endophytes. Two isolates of Fusarium falciforme and one isolate of Fusarium graminearum were selected for co-culture experiments with T. versicolor.A comprehensive metabolic analysis of the confrontation zones using RPLC-ESI(+)-HRMS/MS and molecular networking revealed that the antifungal activity against T. versicolor was primarily mediated by cyclopeptides, and the observed contact inhibition was attributed to fusarins. These findings shed new light on the role of endophytic fungi in the chemical defense strategies of S. rubra, highlighting their potential as a source of bioactive compounds with antifungal properties
Eco-ES 2025: 3rd workshop on Eco-design and circular economy of Electronic Systems
No full textAs this document is a collection of abstracts, to cite a single abstract, please report only the authors and the title of the contributionInternational audienceMany environmental impacts arise from electronics and, among them, electronic waste is rising quickly to the top of priority issues. Because of the number of electronic systems growing exponentially and their short life cycles, Europe asks for strong and rapid actions towards a sustainable development and use of electronics. Eco-design and circular economy applied to electronic systems are thus becoming major challenges for the electronic community to respond to the dangers for the environment; besides the exponential increase in electronic waste generation, other issues are the depletion of resources, the contribution to climate change and the poor resiliency to supply-chain. Electronic designers willing to engage in eco-design face several difficulties, related in particular to a limited knowledge or a lack of data to estimate the environmental impact from the design phase. Other difficulties come from the challenging application of circular economy strategies to electronics and the uncertain extension of the service lifetime of the system or parts of the system, owing to the variability in user behavior and business models.The objective of the workshop Eco-ES is to gather experts from both academia and industry, covering a wide scope in the environmental sustainability of electronics. Eco-ES is proposed as a workshop of the conference DATE since 2023. In the third edition at DATE 2025, the event hosted a keynote of Jean-Pierre Raskin (UCL), an invited talk of Marc Jouss´e (Retronix) and talks selected from an open call. This document collects the abstracts of the talks
Exploration du lien entre l’incidence de la COVID-19 et le taux de létalité par infection lors de la première vague pandémique
No full textLes autres auteurs présents sur le DOI appartiennent au SAPRIS-SERO study group. Une demande de rectification de la liste des auteurs sur la publication pour la rendre plus lisible est en cours auprès de l'éditeur.International audienceSeveral studies found an association between COVID-19 incidence, cumulated over the first pandemic wave, and the risk of death for infected individuals. They attributed this association to hospital overload. We studied this association across the French departments using 82,467 serological samples and a hierarchical Bayesian model with spatial smoothing. In high-incidence areas, we hypothesized that hospital overload would increase infection fatality rate (IFR) without increasing infection hospitalization rate (IHR). The analyses were adjusted for intensive care beds per capita, age of the population, and diabetes prevalence (as a surrogate for obesity). We found that increasing departmental incidence from 3 to 9% rose IFR from 0.42 to 1.14% (difference 0.72%, 95% CI 0.49-1.01%), and IHR from 1.66 to 3.61% (difference 1.94%, 95% CI 1.18-2.80%). An increase in incidence from 6 to 12% in people under 60 was associated with an increased proportion of people over 60 among those infected, from 11.6 to 17.4% (difference 5.8%, 95% CI 2.9-8.8%). Higher incidence increased the risk of death for infected individuals and their risk of hospitalization by the same magnitude. These findings could be explained by a higher age among infected individuals in high-incidence areas, rather by than hospital overload
Various Sizes and Shapes of Mixed-Anion Fe(NH<sub>2</sub>trz)<sub>3</sub>(BF<sub>4</sub>)<sub>2-x</sub>(SiF<sub>6</sub>)<sub>x/2</sub>@SiO<sub>2</sub> Nanohybrid Particles Undergoing Spin Crossover Just Above Room Temperature
No full textInternational audienceSpin crossover (SCO) iron (II) coordination compounds in the form of nanohybrid SCO@SiO2 particles were prepared using a reverse micelles technique based on the TritonX-100/cyclohexane/water ternary system. Tetraethyl orthosilicate (TEOS) acts as precursor of both the SiF62- counter-anion and SiO2 to obtain Fe(NH2trz)3(BF4)2-x(SiF6)x/2@SiO2 nanoparticles with different sizes and morphologies while modifying the TEOS concentration and reaction time. The adjustable mixed-anion strategy leads to a range of quite scarce abrupt spin crossover behaviors with hysteresis just above room temperature (ca. 293 K), which is very promising for the integration of these materials into functional devices
Tree species hyperdominance and rarity in the South American Cerrado
No full textInternational audienceThe South American Cerrado, the largest savanna of the Americas and the world's most tree-biodiverse, is critically endangered, with just 8% protected and more than half deforested. However, the extent of its tree diversity and abundance remains poorly quantified. Using a unique biome-wide eco-floristic dataset with 222 one-hectare plots, we estimate the Cerrado has ~1605 tree species and has extreme hyperdominance, with fewer than 2% (30 species) accounting for half of all trees. A single family, Vochysiaceae, represents 17% of all trees, and the most abundant species, Qualea parviflora, accounts for 1 in 14 trees. In contrast, 63% of the species are rare, with fewer than 100 trees across all plots. Remote sensing and spatial modelling suggest the Cerrado has lost 24 billion trees since 1985, equivalent to three times the Earth's human population. We estimate up to 800 tree species may remain undetected in Cerrado ecosystems and could face extinction in a few decades due to deforestation. This hyperdominance parallels patterns in Amazonian forests and highlights risks both biomes face for species loss due to fragmentation, deforestation, and land-use change. Our findings highlight the Cerrado’s critical but undervalued role in global biodiversity, its vulnerabilities, and the urgent need for conservation to avoid irreversible species and biome loss
Tannin with sodium carbonate: A single additive for poured earth concrete with tropical soils
No full textInternational audienceBuilding sustainable earth construction to replace cement concrete is a major challenge in fast-developing tropical regions. Poured earth, shaped like concrete, offers a cost-effective and eco-friendly alternative. Poured earth usually relies on industrial dispersants and hydraulic binders to fluidify and solidify the soil paste. However, these additives strongly increase environmental costs. Recent studies have highlighted the potential of tannins, which are organic extracts from wood, as an eco-friendly alternative. In particular, tannins combined with iron oxides can fluidify soils at an elevated pH, and chemical reactions between tannins and iron oxides lead to rapid solidification, enabling rapid unmolding and improving water resistance. Tropical soils naturally have a high iron oxide content. This study investigated whether tannins could react with the iron oxides naturally present in tropical soil and be used as a single additive for poured earth. Optimal reactions between soils, tannins and iron oxides require an elevated soil pH, and tannins were combined with sodium carbonate (Na2CO3), a low-cost, eco-friendly alkali. Mortars prepared with different dosages of tannin+Na2CO3 were tested and compared to the industrial dispersant sodium hexametaphosphate (NaHMP), using three tropical soils from French Guiana. Results showed that both tannin+Na2CO3 and NaHMP could fluidify the three soils, improved mechanical strength and water resistance, and reduced initial water content and shrinkage. However, tannin+Na2CO3 induced faster solidification, which was attributed to the formation of ferric tannate observed by infrared spectroscopy (ATR-FTIR). This study paves the way for designing poured earth with tropical soil using a single, largely bio-sourced additive: tannin+Na2CO3
Independent domestication and cultivation histories of two West African indigenous fonio millet crops
No full textData availability: White and black fonio accessions are conserved in national collections, and duplicates covered by the Material Transfer Agreement (MTA) are stored in the ARCAD gene bank (Montpellier, France). The raw sequences retrieved from Abrouk et al. are available on EBI-ENA under accession PRJEB36539. The annotation of the CM05836 genome is available at the DRYAD database [https://doi.org/10.5061/dryad.2v6wwpzj0]. The new raw sequencing data re-sequenced in this study are available at EBI-ENA under accession PRJEB80862. Passport data of the accessions and VCF files used to perform the analyses are openly available in DataSuds repository [https://doi.org/10.18167/DVN1/OYTQO6]. Data reuse is granted under CC-BY licence. Source data are provided with this paper.Code availability: Scripts for the bioinformatics pipeline and for the different analyses carried out throughout the paper are available in the Zenodo repository [https://zenodo.org/records/15267221]. Previously reported pipeline and codes to run the k-mer analyses are available on the IRD Forge [https://forge.ird.fr/diade/iKISS].International audienceCrop evolutionary history and domestication processes are key issues for better conservation and effective use of crop genetic diversity. Black and white fonio ( Digitaria iburua and D. exilis , respectively) are two small indigenous grain cereals grown in West Africa. The relationship between these two cultivated crops and wild Digitaria species is still unclear. Here, we analyse whole genome sequences of 265 accessions comprising these two cultivated species and their close wild relatives. We show that white and black fonio were the result of two independent domestications without gene flow. We infer a cultivation expansion that began at the outset of the CE era, coinciding with the earliest discovered archaeological fonio remains in Nigeria. Fonio population sizes declined a few centuries ago, probably due to a combination of several factors, including major social and agricultural changes, intensification of the slave trade and the introduction of new, less labour-intensive crops. The key knowledge and genomic resources outlined here will help to promote and conserve these neglected climate-resilient crops and thereby provide an opportunity to tailor agriculture to the changing world
Understanding the Sargassum phenomenon in the Tropical Atlantic Ocean: From satellite monitoring to stranding forecast
No full textInternational audienceSince 2011, massive strandings of holopelagic Sargassum have occurred on the coasts of the Caribbean and of West Africa. Although open ocean Sargassum mats are oases of biodiversity, their stranding has a number of negative ecological, economic and health consequences. To limit these impacts, Sargassum needs to be collected as quickly as possible to avoid its decomposition, which requires accurate predictions of the date, location and abundance of the strandings. Two complementary approaches have been developed for this purpose: satellite remote sensing technique, to detect Sargassum aggregations, and modeling, to forecast Sargassum displacement and growth. The objective of this review is to provide a synthesis of the current knowledge related to Sargassum monitoring in the tropical Atlantic Ocean. To better understand the issues surrounding Sargassum and its monitoring, the first two parts are devoted to an overview of the ecology of the two most prevailing holopelagic Sargassum species, to the current issues related to their strandings, to the causes of their occurrence in the tropical Atlantic Ocean and to their seasonal and interannual variabilities. The methods used to detect Sargassum from satellite images and their limitations are examined. The transport and biogeochemical models developed for seasonal forecast and stranding predictions are described along with their limitations. As both detection and modeling rely on validation data to assess their accuracy, previous works providing in situ characterization of Sargassum are also reviewed here. The last part provides recommendations to further increase knowledge on holopelagic Sargassum and improve the predictions of their strandings
Halophilic archaea produce wax esters and use an alternative fatty acyl-coenzyme A reductase for precursor synthesis
No full textInternational audienceWax esters (WE) are fatty acid-based neutral lipids thought to be restricted to bacteria and eukaryotes, playing a key role in the functioning and maintenance of cells, especially under adverse conditions. Here, we show that several halophilic archaea (Halobacteriales) carry a homolog of the bacterial wax synthase gene. WE synthesis and accumulation are demonstrated in one of these (poly)extremophilic archaea, Natronomonas pharaonis, during growth on long-chain fatty acids. Our bioinformatic analysis also shows that the synthesis of fatty alcohols required for WE synthesis could be performed by an enzyme evolutionarily related to Class-I 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (HMGR, classically involved in the isoprenoid biosynthesis pathway). Using heterologous expression and enzymatic assays, we show that this HMGR homolog, which we named FcrA (for fatty acyl-CoA reductase), reduces fatty acyl-CoA to fatty alcohol but cannot reduce HMG-CoA to mevalonate, contrasting with the canonical HMGR. The conservation of HMGR catalytic residues in FcrA suggests that the two enzymes have a similar catalytic mechanism, whereas an elongated substrate-binding pocket and distinct residues may explain FcrA's selectivity for fatty acyl-CoA. In addition to archaea, FcrA is present in a wide range of bacteria, including ~25% of those predicted to produce WEs, and accounts for a large proportion of the fatty acyl-CoA reductases found in various environments. Challenging the long-held paradigm that archaea cannot biosynthesize fatty acid-based neutral lipids de novo, this study lays the foundation for further physiological, ecological, and biotechnological investigations of neutral lipid production by systems markedly different from those of eukaryotes and bacteria
Type V: A sex-linked crossed resistance to three Cydia pomonella granulovirus isolates, with different levels of dominance
No full textInternational audienceThe codling moth (Cydia pomonella), is known to be resistant to many (bio)insecticides, including the Cydia pomonella granulovirus (CpGV). Of the multiple isolates available on the European market, two are already known to have selected resistance: Type I to CpGV-M and type II or III to group E (CpGV-S or -R5). In 2019, a monitoring program revealed three wild populations of insects with reduced susceptibility to the three main used virus isolates (CpGV-M, -R5 and -V15). In this context, our aim was to characterise this new type of resistance, referred to as Type V, and to determine its inheritance pattern and degree of dominance, and to investigate whether and how it differs from previously described resistance mechanisms.We collected a population previously identified as multiresistant from which several lines were isolated and selected during 13 generations with either CpGV-M, -R5 or no virus. Bioassays clearly showed high levels of resistance to CpGV-M, -R5 and -V15, as well as cross-resistance between the three isolates. Individual crossing experiments showed different inheritance modes for resistance to CpGV-M and CpGV-R in type V. Resistance to CpGV-M appeared dominant Z-linked as in type I, while it was more likely recessive, but still Z-linked for resistance to CpGV-R. Altogether, Type V is a novel type of resistance that cannot be overcome by CpGV-V15, and marked by a distinct inheritance pattern. Further research is needed to understand the relationship between resistance to each isolate, and adapt the future pest management strategies