École Pratique des Hautes Études

Alzheimer's disease (AD) is a severe form of dementia, which occurrence increases with age and lifestyle conditions. It is characterized by amyloid protein accumulation forming senile plaques, hyperphosphorylated tau protein forming neurofibrillary tangles, neuroinflammation, and oxidative stress, leading to synapse loss and cell death. Pharmacological alternatives to conventional treatments include alkaloids with anti-inflammatory and antioxidant properties. Sesquiterpene lactones, such as Xanthatin-13-(pyrrolidine-2-carboxylic acid) (XPc) from burdock leaf, show promise due to their antioxidant activity targeting glucose-6-phosphate dehydrogenase. This study evaluated XPc's protective effects invivo using Aβ25-35-treated mice, a pharmacological AD model, and explores its synergistic potential with neuroprotective agents like TSPO activators or sigma-1 receptor agonists. Mice were administered Aβ25-35 peptide (9 nmol ICV) and XPc (0.3-3 mg/kg) daily for 4 days. Behavioral tests assessed memory deficits and anxiety. Post-sacrifice, brains were analyzed for neuroinflammation and oxidative stress markers. Combination studies involved XPc with the TSPO activator PK11195 or the sigma-1 receptor agonist PRE-084, with memory evaluated in two behavioral tests. Combination indices were calculated to assess synergy. XPc (1-3 mg/kg) prevented Aβ25-35-induced memory impairments and anxiety. It reduced astroglial reaction, blocked microglial activation, and confirmed antioxidant activity by lowering lipid peroxidation and protein nitrosylation. Combinations with PK11195 or PRE-084 showed synergistic protection in memory tests. XPc is a potent neuroprotective agent against AD-like toxicity in this murine model, effective alone or in synergistic combinations with other drugs.

Abstract Myrmeleontini is a widespread antlion tribe within the lacewing family Myrmeleontidae, well known for its larvae building cone‐shaped pits in sandy soil to trap prey. The monophyly of the tribe is well supported, but the monophyly of many genera within the tribe as well as the definition of the genus Myrmeleon Linnaeus has long been questioned. Here, we present a phylogenomic analysis of Myrmeleontini with emphasis on the Eurasian fauna, using ultraconserved elements (UCE) data. Our results recovered Myrmeleon as a diverse grade, with Baliga Navás, Callistoleon Banks, Euroleon Esben‐Petersen, Hagenomyia Banks and Megistoleon Navás deeply nested within it. Based on our sampling of type species of many genera (including those synonymized with Myrmeleon ) and detailed morphological comparisons, we provide a new phylogeny‐based classification of Myrmeleontini. Accordingly, Myrmeleon s. str . only refers to the formerly recognized M. formicarius group from Palaearctic region. The status of 12 genera that were previously considered as junior synonyms of Myrmeleon is restored (i.e., Banyaleon Zheng & Liu nom. n ., Bordus Navás stat. rev ., Callistoleon Banks stat. rev ., Cocius Navás stat. rev ., Enza Navás stat. rev ., Macroleon Banks stat. rev ., Moreyus Navás stat. rev ., Morter Navás stat. rev ., Neleon Navás stat. rev ., Neseurus Navás stat. rev ., Myrmeleodes Navás stat. rev . and Tafanerus Navás stat rev .), while Neohornius stat. rev ., previously treated as a subgenus of Myrmeleon, is herein elevated to genus. Additionally, based on comprehensive sampling from the Oriental region, five new genera from this region are described, that is, Ancyroleon Zheng & Liu gen. n ., Baligaptes Zheng & Liu gen. n . Melanobaliga Zheng & Liu gen. n ., Orientaleon Zheng & Liu gen. n . and Sinobaliga Zheng & Liu gen. n .

Revue bilingue publiant des articles en sciences humaines et sociales consacrés à l’étude du monde anglophone - A bilingual humanities journal centred on the English-speaking world - Interdisziplinäre Revue, für Geisteswissenschaften und Gesellschaften in der englischsprechenden Welt

The northeastern Atlantic species of the gastropod genus Jujubinus Monterosato, 1884 (Trochidae, Cantharidinae) are reviewed based on an integrative taxonomic approach. Based on a comprehensive phylogenetic framework of cantharidine genera, it is suggested that the scope of the genus Jujubinus should be restricted to a radiation in the northeastern Atlantic and the Mediterranean, not including the tropical Indo-West Pacific species frequently ascribed to it. For Trochus montagui Wood, 1828, traditionally ascribed to Jujubinus, we did not find unequivocal evidence of it belonging in this clade, but rather we found some indication of a closer relationship with Clelandella miliaris (Brocchi, 1814) than with the Jujubinus clade. Thirteen morphospecies were checked against a DNA-barcoding dataset (cox1) and a molecular phylogenetic framework (cox1, 16S, single genes and combined datasets, analysed by Bayesian inference and Maximum Likelihood analyses). Twenty-two secondary species hypotheses were eventually retained. For fifteen of them an available name has been found; seven are herein described as new.

Antarctic ice-core records reveal that over the past 800 000 years (800 kyr), atmospheric pCO₂ closely tracked global climate variability on orbital timescales, declining progressively to ~180 ppm during glacial periods and increasing rapidly by 50–100 ppm during glacial terminations. The Southern Ocean is widely recognized as a key regulator of atmospheric pCO₂ at these timescales, owing to its strong influence on global air–sea CO₂ exchange through coupled physical and biological processes. In particular, the marine biological pump plays a central role: while the production and export of organic carbon reduce surface-ocean and atmospheric pCO₂, the formation and export of biogenic carbonate increase surface-ocean pCO₂ and may partially offset this drawdown. Consequently, variations in the balance between organic and inorganic carbon export—commonly expressed as the export rain ratio—exert a first-order control on atmospheric pCO₂. Although this ratio is relatively well constrained in the modern ocean, its past variability remains poorly documented.Here, we reconstruct glacial–interglacial changes in the rain ratio across the Southern Ocean using a combination of micropaleontological (coccoliths and foraminifera) and geochemical (CaCO₃, total organic carbon (TOC), δ¹³C, C/N) records from sediment core MD04-2718 (1428 m water depth; 48°53.31′S, 65°57.42′E), located in the Polar Front Zone (PFZ, Indian sector), complemented by published records from the Subantarctic Zone (SAZ). We show that sedimentary CaCO₃ primarily reflects the export of biogenic carbonate by calcifying phytoplankton and zooplankton, whereas TOC records the export of phytoplankton-derived organic carbon. Accordingly, TOC/CaCO₃ ratios provide a robust proxy for past variations in the rain ratio.Our results indicate higher rain ratios during glacial periods, driven by enhanced organic carbon export associated with increased diatom productivity, as colder conditions and intensified iron-rich dust inputs prevailed. In contrast, lower rain ratios during interglacials reflect strengthened carbonate export, as warmer conditions and enhanced macronutrient supply from reinvigorated Southern Ocean upwelling, favored coccolithophore and foraminifera productivity. These patterns further suggest that glacial northward migration of the polar front system, combined with reduced sea-surface temperatures and expanded sea-ice cover, promoted an equatorward retreat of coccolithophores and a northward expansion of diatom-dominated ecosystems, with opposite trends during interglacial periods. Because increases in rain ratios generally coincide with declining atmospheric pCO₂, our results support a role for glacial–interglacial rain-ratio dynamics in the SAZ–PFZ — driven by shifts between silica- and carbonate-producing phytoplankton communities — in modulating the global carbon cycle.

Aquifers may naturally contain undesirable and toxic trace elements, known as geogenic contaminants. The presence of these micropollutants poses a major challenge for groundwater management, and has health, economic, and environmental consequences.Areas with high concentrations, either elevated or exceed the guideline value of water standards, are generally identified through the analysis of groundwater data. However, it should be possible to predict these occurrences based on their presence in the solid matrices of aquifers and their mobilization controlled by the physicochemical conditions of the water.To better predict the occurrence of inorganic natural pollutants, we have developed a methodology, based on an integrated approach to better understand the distribution of these elements in aquifers, the conditions controlling their presence, and their evolution in groundwaters.The methodology combines two complementary approaches: i) predictions of geogenic elements content in rocks, including their speciation, using a source to sink methodology are cross-correlating with ii) hydrogeochemistry to identify water-rock interaction processes and the potential mobility of the elements according to physicochemical conditions (e.g., redox conditions). This makes it possible to predict the spatial distribution of geogenic elements (e.g. As, Se, F, etc.) as well as the processes of mobilization in groundwater.Using a geographic information system (GIS), this study compares predicted occurrences using a source-to-sink (S2S) approach with available data including a large dataset on groundwater quality data (ADES data base, a national database publicly available). By interpretating the chemical composition of water, geochemical modelling via PHREEQC and geological data, it is possible to confirm but also to contribute to the S2S modelling.The study focuses on aquifers linked to the Massif Central (France). Geological source-to-sink paleomaps and drilling data are used to correlate the availability in sedimentary deposits of elements such as arsenic (As), selenium (Se), fluorine (F), with the main periods of erosion, transfer, deposit and remobilisation between the end of the Cretaceous and the Miocene. Arsenic, in particular, is studied in various geological layers with a focus on its speciation and mobilization in confined aquifers such as the Beauce calcareous confined aquifer (Southern Paris Basin).This approach presents a real interest in terms of groundwater quality, as it helps to anticipate water quality degradation linked to groundwater exploitation in aquifer impacted by the natural presence of geogenic metals.This work is part of the PEPR OneWater DEESAC project (France 2030), illustrating a transdisciplinary approach combining geology, geophysics, geochemistry, and hydrogeology.