MTs in Palaemonetes argentinus as potential biomarkers of zinc contamination in freshwaters

Aquatic invertebrates take up and accumulate essential and non-essential trace metals even when both are likely to be poisonous. In order to study the potential of the metallothioneins (MTs) as biomarkers of metal contamination in native shrimp Palaemonetes argentinus, organisms have been exposed at 0, 5, 50 and 500 μg L-1 of zinc for 96 h. Moreover, accumulation and subcellular distribution of this essential metal were evaluated. A significant Zn accumulation was observed in different body sections. Higher Zn levels occurred in cephalothorax compared to abdomen, especially at the highest exposure concentration (500 μg Zn L-1). A clear differential subcellular metal distribution between cephalothorax and abdomen was also observed. In cephalothorax Zn was similarly distributed between the soluble and insoluble fractions; while in abdomen, when total Zn increased, insoluble metal augmented more markedly than the soluble one. Cytosolic Zn levels increased more in cephalothorax than in abdomen of shrimps exposed to 500 μg Zn L-1 when compared to control. Finally, a significant induction of MTs was observed in cephalothorax at 500 μg Zn L-1. A potential role for MTs as biomarkers in P. argentinus should be further studied to enhance the sensitivity of the response, although it is likely that MTs play a key role in metal detoxification since the increase of these proteins is linked to metal challenge.Fil: Bertrand, Lidwina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Monferran, Magdalena Victoria. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Métais, Isabelle. Université Catholique de l'Ouest; FranciaFil: Mouneyrac, Catherine. Université Catholique de l'Ouest; FranciaFil: Amé, María Valeria. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentin

Effect of size continuum from nanoplastics to microplastics on marine mussel Mytilus edulis: Comparison in vitro/in vivo exposure scenarios

International audienceFor several decades, plastic has been a global threat in terms of pollution. Plastic polymers, when introduce in the aquatic environment, are exposed to fragmentation processes into microplastics (MPs) and nanoplastics (NPs) which could potentially interact with living organisms. The objective of this work was to study the effects of plastic particles representative of those found in the environment, on the marine mussels Mytilus edulis, under two exposure scenarii: in vivo and in vitro. Whole mussels or cultured hemocytes were exposed for 24 hours to NPs and MPs generated from macro-sized plastics collected in the field, but also to reference NPs, at concentrations found in the environment: 0.08, 10 μg and 100 μg.L-1. Results showed that immune response was only activated when mussels were exposed in vivo. However, cytotoxicity (hemocyte mortality) and genotoxicity (DNA damage) parameters were induced after both types of exposure, but in a dose-dependent manner after in vitro hemocyte exposure to all tested plastic conditions. These results indicate that in vitro approaches could be considered as potential predictors of in vivo exposures

Multiscale analysis of living benthic foraminiferal heterogeneity: Ecological advances from an intertidal mudflat (Loire estuary, France)

International audienceAn unprecedented sampling effort on the Loire estuary allowed a multi scale approach to identify parameters controlling density variations of benthic foraminifera. Indeed, the distances between the samples analysed for this study vary from 1 cm to hundreds of kilometres. To catch this range of distance variations, a model called Scale Variance Analysis was build describing the participation of each scale to the total observed variance. The SVA model requires, for each scale, the stability of relative variance. A comparison with the Moran's Index and experimental variogram is proposed showing coherent conclusions with the SVA analysis. The analysis shows that in order to maximize information on foraminiferal density variation, sampling campaigns should be designed with stations distant from few meters to 1 km, with a particular focus on the hectometre scale. A range of scale too rarely investigated in the community of benthic foraminifera ecology. Next, based on two intertidal mudflat stations separated of few hundred meters, the present study shows that for Ammonia tepida, the scale dependant preponderant parameters is the Chl a concentration in the top first centimetre. Contrastingly, the indicators of food quality such as the lability index and the oxygen penetration depth do not seem to affect A. tepida densities. This high quantity, low quality diet is interpreted as an opportunistic behaviour that is indirectly confirmed by a kinetic approach. This approach compares the deep infaunal microhabitat density with the shallow infaunal microhabitat density. The identical ratio indicates quick saturation of the available resources

The E3 Ubiquitin Ligase Asb2α in T Helper 2 Cells Negatively Regulates Antitumor Immunity in Colorectal Cancer

International audienceThe escape of cancer cells from host immunosurveillance involves a shift in immune responses, including an imbalance in Th1 and Th2 cells. A Th1-dominated immune response predicts positive outcomes in colorectal cancer. The E3 ubiquitin ligase, Asb2α, is expressed in Th2 cells, but its roles in T-cell maturation and cancer are unclear. We provide evidence that the Th2 master regulator, Gata3, induces Asb2 Loss of Asb2 did not affect Th differentiation ex vivo, but reduced IL4 production from Th2 cells. We found that high ASB2 expression was associated with poor outcome in colorectal cancer. Loss of Asb2 from hematopoietic cells promoted a Th1 response and attenuated colitis-associated tumorigenesis in mice. Diminished Th2 function correlated with increased IFNγ production and an enhanced type 1 antitumor immune response in Asb2-deficient mice. Our work suggests that Asb2α promotes a Th2 phenotype in vivo, which in turn is associated with tumor progression in a mouse model of colitis

J-DISTAS : creation of interoperable tools for the estimation of field readiness

International audienceSustainable crop production implies a high efficiency of field operations and protection of the soil as a natural resource. The soil workability refers to the suitability of soil for cultural operations, and the soil trafficability defines the soil capacity to support machinery during traffic without soil physical degradation. The combination of these two factors the so-called field readiness, allows a decision to be made about timing and conditions of field operations for execution of operations in an efficient and cost-effective way. The concept of field readiness allows also strategic decisions such as the evolution of cropping systems or the acquisition of agricultural machinery. The tools developed in France are mostly related to workability and dates from the years 1990’s. They need to be upgraded to better consider compaction risk, according to machinery evolution. The Terranimo model now offers the possibility to estimate compaction risk. The J-DISTAS project (2019-2022) aims at evaluating these tools in our current French context and upgrade them to create a prototype of interoperable tools which includes all the aspects linked to the concept of field readiness.The project is divided in four work packages (WP):WP2 Collect data: gather data from previous field experiments and carry out new specific field trials on six experimental sites.WP3 Evaluate and improve or adapt existing tools to calculate indicators of soil workability and trafficability.WP1 Build the decisional tool to define if a day is available or not depending on previous indicators and evaluate (i) its ability to take the good decision and (ii) its sensibility to uncertainties in some input data.WP4 Ensure transfer and valorization mainly by the implementation of the protype in a platform and the communication to land managers.After two years, the main result is a panel of common methods and procedures for field and laboratory measurements used to collect data from different field operations: shallow tillage, seeding, mechanical weeding, mechanical cover crop destruction, manure spreading and harvest. Three types of data are collected in each field experiments in order to (i) characterize the conditions of the field operation: the climate conditions, the specifications of the machinery (wheel load, tyre inflation pressure), and relevant soil characteristics (visual assessment of the soil structure, soil water content and matric potential, soil mechanical strength); (ii) asses the efficiency of the operation; and (iii) evaluate the impact of the operation on soil structure by visual assessment, bulk density and air permeability measurements. Data were collected from 75 fields trials in 2019 and 2020, and the data analysis begins to identify which minimum conditions should be fulfilled for both workability and trafficability.Results of J-DISTAS could be used in the conception of cropping systems, or optimization of mechanical cost. The inter-operable tools developed in the project can be used as a decision support tool that includes field readiness in strategic decisions and helps to the soil physical quality protection

Is there a link between acetylcholinesterase, behaviour and density populations of the ragworm Hediste diversicolor?

International audienceThe main objective of the present study was to explore the potential link between acetylcholinesterase (AChE) activity and burrowing behaviour of the ragworm Hediste diversicolor, which may have consequences at higher levels of biological organisation. Two complementary studies were conducted. AChE activity, at the sub-individual level, and behavioural responses, at the individual level, were evaluated in worms from the Loire estuary (France), whereas density and biomass of H. diversicolor were determined at the population level. A Spearman positive correlation between both biomarkers (AChE and burrowing) suggested that inhibition of AChE activity was linked to behaviour impairments. At the population level, lower AChE and behaviour activities were detected in worms corresponding to lower population density and biomass. These results provide direct empirical field evidence demonstrating the sensitivity of behaviour of H. diversicolor as a biomonitor of estuarine health status assessment.Copyright © 2019 Elsevier Ltd. All rights reserved

ASB2α regulates migration of immature dendritic cells

International audienceThe actin-binding protein filamins (FLNs) are major organizers of the actin cytoskeleton. They control the elasticity and stiffness of the actin network and provide connections with the extracellular microenvironment by anchoring transmembrane receptors to the actin filaments. Although numerous studies have revealed the importance of FLN levels, relatively little is known about the regulation of its stability in physiological relevant settings. Here, we show that the ASB2α cullin 5-ring E3 ubiquitin ligase is highly expressed in immature dendritic cells (DCs) and is down-regulated after DC maturation. We further demonstrate that FLNs are substrates of ASB2α in immature DCs and therefore are not stably expressed in these cells, whereas they exhibit high levels of expression in mature DCs. Using ASB2 conditional knockout mice, we show that ASB2α is a critical regulator of cell spreading and podosome rosette formation in immature DCs. Furthermore, we show that ASB2(-/-) immature DCs exhibit reduced matrix-degrading function leading to defective migration. Altogether, our results point to ASB2α and FLNs as newcomers in DC biology