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International audience; The use of autoantigen-specific regulatory T cells (Tregs) as a cellular therapy for autoimmune diseases is appealing. However, it is challenging to isolate and expand large quantity of Tregs expressing disease-relevant T-cell receptors (TCR). To overcome this problem, we used an approach aiming at redirecting the specificity of polyclonal Tregs through autoreactive TCR gene transfer technology. In this study, we examined whether Tregs engineered through retroviral transduction to express a TCR cross-reactive to two CNS autoantigens, myelin oligodendrocyte glycoprotein (MOG) and neurofilament-medium (NF-M), had a superior protective efficacy compared with Tregs expressing a MOG mono-specific TCR. We observed that engineered Tregs (engTregs) exhibited in vitro regulatory effects related to the antigenic specificity of the introduced TCR, and commensurate in potency with the avidity of the transduced TCR. In experimental autoimmune encephalomyelitis (EAE), adoptively transferred engTregs proliferated, and migrated to the CNS, while retaining FoxP3 expression. EngTregs expressing MOG/NF-M cross-reactive TCR had superior protective properties over engTregs expressing MOG-specific TCR in MOG-induced EAE. Remarkably, MOG/NF-M bi-specific TCR-engTregs also improved recovery from EAE induced by an unrelated CNS autoantigen, proteolipid protein (PLP). This study underlines the benefit of using TCRs cross-reacting towards multiple autoantigens, compared with mono-reactive TCR, for the generation of engTregs affording protection from autoimmune disease in adoptive cell therapy.

International audience; ObjectivesSeveral automated algorithms for epidemiological surveillance in hospitals have been proposed. However, the usefulness of these methods to detect nosocomial outbreaks remains unclear. The goal of this review was to describe outbreak detection algorithms that have been tested within hospitals, consider how they were evaluated, and synthesize their results.MethodsWe developed a search query using keywords associated with hospital outbreak detection and searched the MEDLINE database. To ensure the highest sensitivity, no limitations were initially imposed on publication languages and dates, although we subsequently excluded studies published before 2000. Every study that described a method to detect outbreaks within hospitals was included, without any exclusion based on study design. Additional studies were identified through citations in retrieved studies.ResultsTwenty-nine studies were included. The detection algorithms were grouped into 5 categories: simple thresholds (n = 6), statistical process control (n = 12), scan statistics (n = 6), traditional statistical models (n = 6), and data mining methods (n = 4). The evaluation of the algorithms was often solely descriptive (n = 15), but more complex epidemiological criteria were also investigated (n = 10). The performance measures varied widely between studies: e.g., the sensitivity of an algorithm in a real world setting could vary between 17 and 100%.ConclusionEven if outbreak detection algorithms are useful complementary tools for traditional surveillance, the heterogeneity in results among published studies does not support quantitative synthesis of their performance. A standardized framework should be followed when evaluating outbreak detection methods to allow comparison of algorithms across studies and synthesis of results.

Summertime Arctic shipboard observations of oxygenated volatile organic compounds (OVOCs) such as organic acids, key precursors of climatically active secondary organic aerosol (SOA), are consistent with a novel source of OVOCs to the marine boundary layer via chemistry at the sea surface microlayer. Although this source has been studied in a laboratory setting, organic acid emissions from the sea surface microlayer have not previously been observed in ambient marine environments. Correlations between measurements of OVOCs, including high levels of formic acid, in the atmosphere (measured by an online high-resolution time-of-flight mass spectrometer) and dissolved organic matter in the ocean point to a marine source for the measured OVOCs. That this source is photomediated is indicated by correlations between the diurnal cycles of the OVOC measurements and solar radiation. In contrast, the OVOCs do not correlate with levels of isoprene, monoterpenes, or dimethyl sulfide. Results from box model calculations are consistent with heterogeneous chemistry as the source of the measured OVOCs. As sea ice retreats and dissolved organic carbon inputs to the Arctic increase, the impact of this source on the summer Arctic atmosphere is likely to increase. Globally, this source should be assessed in other marine environments to quantify its impact on OVOC and SOA burdens in the atmosphere, and ultimately on climate.

chapitre 4; International audience; To understand why and how species invade ecosystems, ecologists have made heavy use of observations of species colonization on islands. The theory of island biogeography, developed in the 1960s by R.H. MacArthur and E.O. Wilson, has had a tremendous impact on how ecologists understand the link between species diversity and characteristics of the habitat such as isolation and size. Recent developments have described how the inclusion of information on trophic interactions can further inform our understanding of island biogeography dynamics. Here, we extend the trophic theory of island biogeography to assess whether certain food web properties on the mainland affect colonization/extinction dynamics of species on islands. Our results highlight that both food web connectance and size on the mainland increase species diversity on islands. We also highlight that more heavily tailed degree distributions in the mainland food web correlate with less frequent but potentially more important extinction cascades on islands. The average shortest path to a basal species on islands follows a hump-shaped curve as a function of realized species richness, with food chains slightly longer than on the mainland at intermediate species richness. More modular mainland webs are also less persistent on islands. We discuss our results in the context of global changes and from the viewpoint of community assembly rules, aiming at pinpointing further theoretical developments needed to make the trophic theory of island biogeography even more useful for fundamental and applied ecology.

Sleep serves crucial learning and memory functions in both nervous and immune systems. Microglia are brain immune cells that actively maintain health through their crucial physiological roles exerted across the lifespan, including phagocytosis of cellular debris and orchestration of neuroinflammation. The past decade has witnessed an explosive growth of microglial research. Considering the recent developments in the field of microglia and sleep, we examine their possible impact on various pathological conditions associated with a gain, disruption, or loss of sleep in this focused mini-review. While there are extensive studies of microglial implication in a variety of neuropsychiatric and neurodegenerative diseases, less is known regarding their roles in sleep disorders. It is timely to stimulate new research in this emergent and rapidly growing field of investigation.

Global patterns of biodiversity have emerged for soil microorganisms, plants and animals, and the extraordinary significance of microbial functions in ecosystems is also well established. Virtually unknown, however, are large-scale patterns of microbial diversity in freshwaters, although these aquatic ecosystems are hotspots of biodiversity and biogeochemical processes. Here we report on the first large-scale study of biodiversity of leaf-litter fungi in streams along a latitudinal gradient unravelled by Illumina sequencing. The study is based on fungal communities colonizing standardized plant litter in 19 globally distributed stream locations between 69°N and 44°S. Fungal richness suggests a hump-shaped distribution along the latitudinal gradient. Strikingly, community composition of fungi was more clearly related to thermal preferences than to biogeography. Our results suggest that identifying differences in key environmental drivers, such as temperature, among taxa and ecosystem types is critical to unravel the global patterns of aquatic fungal diversity. Fil: Seena, Sahadevan. Universidade do Minho; Portugal. Universidad de Coimbra; Portugal Fil: Bärlocher, Felix. Mount Allison University; Canadá Fil: Sobral, Olímpia. Universidade do Minho; Portugal. Universidad de Coimbra; Portugal Fil: Gessner, Mark O.. Leibniz - Institute of Freshwater Ecology and Inland Fisheries; Alemania. Technishe Universitat Berlin; Alemania. Berlin-Brandenburgischen Instituts für Biodiversitätsforschung; Alemania Fil: Dudgeon, David. University of Hong Kong; Hong Kong Fil: McKie, Brendan. Sveriges Lantbruksuniversitet; Suecia Fil: Chauvet, Eric. Institut National des postes et télécommunications; Francia. Centre National de la Recherche Scientifique; Francia. Université Paul Sabatier; Francia Fil: Boyero, Luz. James Cook University; Australia. Universidad del País Vasco; España. Ikerbasque; España Fil: Ferreira, Verónica. Universidad de Coimbra; Portugal Fil: Frainer, André. UiT The Arctic University of Norway; Noruega Fil: Bruder, Andreas. University of Otago; Nueva Zelanda Fil: Matthaei, Christoph. University of Otago; Nueva Zelanda Fil: Fenoglio, Stefano. Università degli Studi del Piemonte Orientale Amedeo Avogadro; Italia Fil: Sridhar, Kandikere. Mangalore University; India Fil: Albariño, Ricardo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Fotobiología; Argentina Fil: Douglas, Michael M.. University of Western Australia; Australia. Charles Darwin University; Australia Fil: Encalada, Andrea C.. Universidad de Coimbra; Portugal. Universidad San Francisco de Quito; Ecuador Fil: Garcia, Erica. Charles Darwin University; Australia Fil: Ghate, Sudeep. Yenepoya University. Yenepoya Research Center; India. Mangalore University; India Fil: Giling, Darren P.. Leibniz - Institute of Freshwater Ecology and Inland Fisheries; Alemania. Universitat Jena; Alemania Fil: Gonçalves, Vítor. Universidade dos Açores. Centro de Investigação em Biodiversidade e Recursos Genéticos; Portugal Fil: Iwata, Tomoya. University of Yamanashi; Japón Fil: Landeira Dabarca, Andrea. Universidad San Francisco de Quito; Ecuador Fil: McMaster, Damien. Charles Darwin University; Australia Fil: Medeiros, Adriana O.. Universidade Federal da Bahia; Brasil Fil: Naggea, Josheena. Monash University Malaysia; Malasia Fil: Pozo, Jesús. Universidad del País Vasco; España Fil: Raposeiro, Pedro. Universidade dos Açores; Portugal Fil: Swan, Christopher M.. University of Maryland; Estados Unidos Fil: Tenkiano, Nathalie S. D.. Université Julius N'yerere de Kankan; Guinea Fil: Yule, Catherine Mary. University of the Sunshine Coast; Australia. Monash University Malaysia; Malasia Fil: Graça, Manuel A. S.. Universidad de Coimbra; Portugal

International audience; The Mg and SO 4 content of naturally occurring calcite are routinely used as paleoenvironmental proxies. Yet little is known about the mechanisms governing the presence of these ions in carbonate minerals when their formation proceeds via an amorphous precursor. To address this, the transformation of Mg-free amorphous calcium carbonate (ACC) into nanocrystalline high-Mg calcite (HMC) was experimentally studied in solutions containing 27 mM of Mg and a range of 10-90 mM of SO 4. The obtained results suggest that ACC is stable for several minutes in the experimental solutions and this amorphous phase actively uptakes Mg and SO 4 that are incorporated in its structure. Additionally, the obtained results suggest that the stabilization of ACC is not affected by its Mg content and that the transformation to HMC is effectively controlled by the abundance of the free Mg 2+ (aq) ion. The transformation of ACC to HMC occurs earlier at elevated SO 4 concentrations because SO 4 limits the availability of Mg 2+ (aq) due to the formation of the MgSO 4 0 (aq) complex. The HMC that is formed from ACC appears as aggregates composed of nanocrystallites and exhibits Mg and SO 4 contents up to 8 and 2 mol% depending on the initial SO 4 concentration in the reactive solution. The precipitated HMC was kept in contact with the reactive solution in order to assess its reactivity for up to 1 year of reaction time. Over time, a continuous exchange of Mg and SO 4 between calcite and reactive solution was observed resulting in enrichment of Mg and depletion of SO 4 affecting the total mass of the aggregates with the distribution of these elements to appear homogeneous in the crystalline solid. The high reactivity and the continuous exchange of solutes between the nanocrystalline calcite and the reactive solutions limits the use of Mg and SO 4 content of these HMCs as environmental proxies.