Evidence of trophic transfer of microcystins from the gastropod Lymnaea stagnalis to the fish Gasterosteus aculeatus.

International audienceAccording to our previous results the gastropod Lymnaea stagnalis exposed to MC-producing cyanobacteria accumulates microcystins (MCs) both as free and covalently bound forms in its tissues, therefore representing a potential risk of MC transfer through the food web. This study demonstrates in a laboratory experiment the transfer of free and bound MCs from L. stagnalis intoxicated by MC-producing Planktothrix agardhii ingestion to the fish Gasterosteus aculeatus. Fish were fed during five days with digestive glands of L. stagnalis containing various concentrations of free and bound MCs, then with toxin-free digestive glands during a 5-day depuration period. MC accumulation was measured in gastropod digestive gland and in various fish organs (liver, muscle, kidney, and gills). The impact on fish was evaluated through detoxification enzyme (glutathion-S-transferase, glutathion peroxydase and superoxyde dismutase) activities, hepatic histopathology, and modifications in gill ventilation, feeding and locomotion. G. aculeatus ingestion rate was similar with intoxicated and toxin-free diet. Fish accumulated MCs (up to 3.96 ± 0.14 μg g−1 DW) in all organs and in decreasing order in liver, muscle, kidney and gills. Hepatic histopathology was moderate. Glutathion peroxydase was activated in gills during intoxication suggesting a slight reactive oxygen species production, but without any impact on gill ventilation. Intoxication via ingestion of MC-intoxicated snails impacted fish locomotion. Intoxicated fish remained significantly less mobile than controls during the intoxication period possibly due to a lower health condition, whereas they showed a greater mobility during the depuration period that might be related to an acute foraging for food. During depuration, MC elimination was total in gills and kidney, but partial in liver and muscle. Our results assess the MC transfer from gastropods to fish and the potential risk induced by bound MCs in the food web

New Cyclodextrin-DOTA Conjugates as MRI Contrast Agent

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New Cyclodextrin-DOTA Conjugates as MRI Contrast Agent

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Honey-induced macrophage stimulation: AP-1 and NF-κB activation and cytokine production are unrelated to LPS content of honey

International audienceHoney is well known for its wound healing properties although the cellular and molecular mechanisms underlying honey-stimulated healing process are still poorly understood. The present study was intended to characterize the stimulation of Raw 264.7 murine macrophages in response to thyme honey. Honey induces significant increase in PGE2 production, and overexpression of both COX-2 and TNF-α (p < 0.001). This increase was concomitant with overexpression and activation of the AP-1 and NF-κB transcription factor subunits. The small LPS content of honey could not, by itself, account for the reported observations. These results suggest that other thyme honey components participate in the stimulation of cytokine production required for effective wound healing process

Correction to: What are the effective solutions to control the dissemination of antibiotic resistance in the environment? A systematic review protocol

International audienceCorrection to: Environ Evid (2018) 7:3 https ://doi.org/10.1186/s1375 0-018-0118-2 : Following publication of the original article [1], the authors reported that wrong website were hyperlinked in the “Methods” section of the paper. The article has been updated and the links have been removed.Reference :1. Goulas A, Livoreil B, Grall N, Benoit P, Couderc-Obert C, Dagot C, Patureau D, Petit F, Laouénan C, Andremont A. What are the effective solutionsto control the dissemination of antibiotic resistance in the environment? A systematic review protocol. Environ Evid. 2018;7:3. https ://doi.org/10.1186/s1375 0-018-0118-2. HAL Id : hal-0172487

Strategies to control the dissemination of antibiotic resistance in the environment: A systematic review including a meta-analysis

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Effect of the second coordination sphere on new contrast agents based on cyclodextrin scaffolds for MRI signals

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Sources and geographical origins of fine aerosols in Paris (France)

International audienceThe present study aims at identifying and apportioning fine aerosols to their major sources in Paris (France) – the second most populated "larger urban zone" in Europe – and determining their geographical origins. It is based on the daily chemical composition of PM2.5 examined over 1 year at an urban background site of Paris (Bressi et al., 2013). Positive matrix factorization (EPA PMF3.0) was used to identify and apportion fine aerosols to their sources; bootstrapping was performed to determine the adequate number of PMF factors, and statistics (root mean square error, coefficient of determination, etc.) were examined to better model PM2.5 mass and chemical components. Potential source contribution function (PSCF) and conditional probability function (CPF) allowed the geographical origins of the sources to be assessed; special attention was paid to implement suitable weighting functions. Seven factors, namely ammonium sulfate (A.S.)-rich factor, ammonium nitrate (A.N.)-rich factor, heavy oil combustion, road traffic, biomass burning, marine aerosols and metal industry, were identified; a detailed discussion of their chemical characteristics is reported. They contribute 27, 24, 17, 14, 12, 6 and 1% of PM2.5 mass (14.7 μg m−3) respectively on the annual average; their seasonal variability is discussed. The A.S.- and A.N.-rich factors have undergone mid- or long-range transport from continental Europe; heavy oil combustion mainly stems from northern France and the English Channel, whereas road traffic and biomass burning are primarily locally emitted. Therefore, on average more than half of PM2.5 mass measured in the city of Paris is due to mid- or long-range transport of secondary aerosols stemming from continental Europe, whereas local sources only contribute a quarter of the annual averaged mass. These results imply that fine-aerosol abatement policies conducted at the local scale may not be sufficient to notably reduce PM2.5 levels at urban background sites in Paris, suggesting instead more coordinated strategies amongst neighbouring countries. Similar conclusions might be drawn in other continental urban background sites given the transboundary nature of PM2.5 pollution

Nitrate radical generation via continuous generation of dinitrogen pentoxide in a laminar flow reactor coupled to an oxidation flow reactor

International audienceOxidation flow reactors (OFRs) are an emerging tool for studying the formation and oxidative aging of organic aerosols and other applications. The majority of OFR studies to date have involved the generation of the hydroxyl radical (OH) to mimic daytime oxidative aging processes. In contrast, the use of the nitrate radical (NO 3) in modern OFRs to mimic nighttime oxidative aging processes has been limited due to the complexity of conventional techniques that are used to generate NO 3. Here, we present a new method that uses a laminar flow reactor (LFR) to continuously generate dinitrogen pentoxide (N 2 O 5) in the gas phase at room temperature from the NO 2 + O 3 and NO 2 + NO 3 reactions. The N 2 O 5 is then injected into a dark Potential Aerosol Mass (PAM) OFR and decomposes to generate NO 3 ; hereafter, this method is referred to as "OFR-iN 2 O 5 " (where "i" stands for "injected"). To assess the applicability of the OFR-iN 2 O 5 method towards different chemical systems, we present experimental and model characterization of the integrated NO 3 exposure, NO 3 : O 3 , NO 2 : NO 3 , and NO 2 : O 2 as a function of LFR and OFR conditions. These parameters were used to investigate the fate of representative organic peroxy radicals (RO 2) and aromatic alkyl radicals generated from volatile organic compound (VOC) + NO 3 reactions, and VOCs that are reactive towards both O 3 and NO 3. Finally, we demonstrate the OFR-iN 2 O 5 method by generating and characterizing secondary organic aerosol from the β-pinene + NO 3 reaction