Ecotoxicity tests and ecoscores to improve soil management : case of a secondary lead smelter plant

International audienceriginally located on the outskirts of cities, numerous industrial sites, sometimes abandoned, are now in urban areas and are therefore likely to have environmental and health risks to surrounding populations. Currently, rehabilitation of the sites frequently entails excavation of polluted soils. Excavated soils can thus follow two different ways: landfilling, expensive and energy intensive, or reuse/recycling, integrated to sustainable development. The choice of a specific track mainly depends on total and leachable concentrations of the pollutant in the soil. Among the numerous pollutants observed in urban and peri-urban areas, trace metals are often present in soils; atmosphere emissions by smelters being one of the main anthropogenic source. MTE speciation and compartmentalization in soils can modify their impact on living organisms

Ecotoxicity tests and ecoscores to improve soil management : case of a secondary lead smelter plant

International audienceriginally located on the outskirts of cities, numerous industrial sites, sometimes abandoned, are now in urban areas and are therefore likely to have environmental and health risks to surrounding populations. Currently, rehabilitation of the sites frequently entails excavation of polluted soils. Excavated soils can thus follow two different ways: landfilling, expensive and energy intensive, or reuse/recycling, integrated to sustainable development. The choice of a specific track mainly depends on total and leachable concentrations of the pollutant in the soil. Among the numerous pollutants observed in urban and peri-urban areas, trace metals are often present in soils; atmosphere emissions by smelters being one of the main anthropogenic source. MTE speciation and compartmentalization in soils can modify their impact on living organisms

Use of ecotoxicity test and ecoscores to improve the management of polluted soils: case of a secondary lead smelter plant

International audienceWith the rise of sustainable development, rehabilitation of brownfield sites located in urban areas has become a major concern. Management of contaminated soils in relation with environmental and sanitary risk concerns is therefore a strong aim needing the development of both useful tools for risk assessment and sustainable remediation techniques. For soils polluted by metals and metalloids (MTE), the criteria for landfilling are currently not based on ecotoxicological tests but on total MTE concentrations and leaching tests. In this study, the ecotoxicity of leachates from MTE polluted soils sampled from an industrial site recycling lead-acid batteries were evaluated by using both modified Escherichia coli strains with luminescence modulated by metals and normalized Daphnia magna and Alivibrio fischeri bioassays. The results were clearly related to the type of microorganisms (crustacean, different strains of bacteria) whose sensitivity varied. Ecotoxicity was also different according to sample location on the site, total concentrations and physico-chemical properties of each soil. For comparison, standard leaching tests were also performed. Potentially phytoavailable fraction of MTE in soils and physico-chemical measures were finally performed in order to highlight the mechanisms. The results demonstrated that the use of a panel of microorganisms is suitable for hazard classification of polluted soils. In addition, calculated eco-scores permit to rank the polluted soils according to their potentially of dangerousness. Influence of soil and MTE characteristics on MTE mobility and ecotoxicity was also highlighted

Génétique du syndrome de Mayer-Rokitansky-Küster-Hauser (étude d'un gène candidat, le gène ITIH5)

Le syndrome de Mayer-Rokitansky-Küster-Hauser (MRKH) est une aplasie utéro-vaginale congénitale pouvant être associée à d'autres malformations. Des cas familiaux ont été décrits. Une délétion chromosomique différente a été découverte chez 4 patientes indépendantes, au sein de loci associés au syndrome de DiGeorge (DGS) (22q11, 10p14, 8p23 et 4q34-ter). En 10p14, un gène, ITIH5, est concerné par la délétion. Il appartient à la famille des gènes ITI ayant un rôle dans la dynamique de la matrice extracellulaire. Chez la souris, l'expression d'Itih5 est forte et s'intensifie au cours du développement dans le tractus génital interne femelle. De plus, les tractus génitaux semblent synthétiser une isoforme protéique d'Itih5 spécifique. Ainsi les loci connus du DGS pourraient être aussi impliqués dans l'étiologie du syndrome MRKH, pouvant conduire à un syndrome dit "de gènes contigus". Enfin, l'haploinsuffisance du gène ITIH5 pourrait rendre compte du syndrome MRKH.The Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is featured by a congenital utero-vaginal aplasia associated with other malformations. Familial cases were described. A different deletion was found in 4 independent patients within the four chromosomal loci affedted in DiGeorge syndrome (DGS) (22q11, 10p14, 8p23 and 4q34-ter). In 10p14-15, one gene, ITIH5, was affected by the deletion. It is a member of the ITI gene family, playing a role in extracellular matrix dynamics. In the mouse, Itih5 expresssion is strong and increases during embryonic development in the female genital tract. Moreover, the genital tracts seem to synthesize a specific isoform of the Itih5 protein. In conclusion, the loci involved in DGS deletion syndrome might as well be involved in the MRKH syndrome which would then be part of a wider and heterogeneous deletion syndrome. Furthermore our results show that ITIH5 haploinsufficiency could account for the MRKH syndrome.RENNES1-BU Santé (352382103) / SudocSudocFranceF

Atypical hyperplasia of the breast: the black hole of routine breast cancer screening.

International audienceAIM: Determination of the prevalence, of the radiological and clinical characteristics, and outcome of atypical hyperplasia (AH) of the breast within a population subjected to routine screening (double-view mammography with double reading, performed every two years between 50 and 75 years of age). PATIENTS AND METHODS: The clinical and radiological records and histological findings of percutaneous and surgical biopsy specimens of sixty-eight patients presenting with AH were reviewed together with patient follow-up data after percutaneous and surgical biopsy. RESULTS: AH incidence in the population was 0.19‰ with the following distribution of lesions: atypical epithelial hyperplasia (AEH, 53%), columnar cell metaplasia with atypia (CCMA, 32%), and lobular intraepithelial neoplasia (LIN, 8%). The mean patient age was 58 years and 24% of patients were receiving hormone replacement therapy. The main radiological finding was the presence of microcalcifications for AEH and CCMA lesions in particular, and the mammograms were valid (correlation between American College of Radiology score and risk of lesion, only 3% of lesions were recognized on the second reading). A total of 13.7% of AH cases were underestimated and a real risk of AH progression was observed, regardless of whether or not surgical biopsy had been performed. CONCLUSION: The clinical and radiological characteristics of AH observed in a population subjected to routine breast cancer screening are identical to those for patients with the same lesions referred to specialist centers. Surgical biopsy remains the recommended option due to the risk of underestimation of lesions by percutaneous biopsy and the risk of progression justifies the need for continued close monitoring

Risks assessment around a lead-batteries recycling company using ecotoxicity tests

With the rise of sustainable development, rehabilitation of brownfield sites located in urban areas has become a major concern. Remediation of contaminated soils is therefore a strong aim with the development of bioremediation and tools for risk assessment. Actually, criteria for landfilling are based on leaching tests that represent the mobilized fraction and therefore may present a risk in case of transfer. However, ecotoxicological tests to guide the landfill are not yet currently used. Nevertheless, their use seems very relevant to assess the actual toxicity of the leachate and better reflects the reality of effects on living organisms. Standard leaching tests (EN 12457-2) asked by European authorities to guide landfilling were first performed on ten samples of soil taken from a site recycling lead-acid batteries. This experiment determines the fraction potentially be mobilized and therefore poses a risk if transferred. Physico-chemical parameters from all samples were also determined (pH, lead total concentrations, etc.). Toxicity of leachate was evaluated by Daphnia magna (OCDE 202) and Alivibrio fischeri (Vibrio fischeri, ISO 11348) bioassays. Besides, four modified Escherichia coli stains with luminescence modulated by heavy metals were also used to assess the toxicity of these pollutants. Results shown that although total lead concentrations can be very high (up to 40 000 mg / kg), only a small fraction was solubilized. Chemical analysis and ecotoxicological bioassays were well correlated. This study highlighted the use of modified bacteria strains sensitive to metals will be useful tools for the end-users for environmental monitoring of contaminated sites

Impact of Bacterial Membrane Fatty Acid Composition on the Failure of Daptomycin To Kill Staphylococcus aureus

International audienceDaptomycin is a last-resort membrane-targeting lipopeptide approved for the treatment of drug-resistant staphylococcal infections, such as bacteremia and implant-related infections. Although cases of resistance to this antibiotic are rare, increasing numbers of clinical, in vitro, and animal studies report treatment failure, notably against Staphylococcus aureus. The aim of this study was to identify the features of daptomycin and its target bacteria that lead to daptomycin treatment failure. We show that daptomycin bactericidal activity against S. aureus varies significantly with the growth state and strain, according to the membrane fatty acid composition. Daptomycin efficacy as an antibiotic relies on its ability to oligomerize within membranes and form pores that subsequently lead to cell death. Our findings ascertain that daptomycin interacts with tolerant bacteria and reaches its membrane target, regardless of its bactericidal activity. However, the final step of pore formation does not occur in cells that are daptomycin tolerant, strongly suggesting that it is incapable of oligomerization. Importantly, membrane fatty acid contents correlated with poor daptomycin bactericidal activity, which could be manipulated by fatty acid addition. In conclusion, daptomycin failure to treat S. aureus is not due to a lack of antibiotic-target interaction, but is driven by its capacity to form pores, which depends on membrane composition. Manipulation of membrane fluidity to restore S. aureus daptomycin bactericidal activity in vivo could open the way to novel antibiotic treatment strategies

Podosome Force Generation Machinery: A Local Balance between Protrusion at the Core and Traction at the Ring

International audienceDetermining how cells generate and transduce mechanical forces at the nanoscale is a major technical challenge for the understanding of numerous physiological and pathological processes. Podosomes are submicrometer cell structures with a columnar F-actin core surrounded by a ring of adhesion proteins, which possess the singular ability to protrude into and probe the extracellular matrix. Using protrusion force microscopy, we have previously shown that single podosomes produce local nanoscale protrusions on the extracellular environment. However, how cellular forces are distributed to allow this protruding mechanism is still unknown. To investigate the molecular machinery of protrusion force generation, we performed mechanical simulations and developed quantitative image analyses of nanoscale architectural and mechanical measurements. First, in silico modeling showed that the deformations of the substrate made by podosomes require protrusion forces to be balanced by local traction forces at the immediate core periphery where the adhesion ring is located. Second, we showed that three-ring proteins are required for actin polymerization and protrusion force generation. Third, using DONALD, a 3D nanoscopy technique that provides 20 nm isotropic localization precision, we related force generation to the molecular extension of talin within the podosome ring, which requires vinculin and paxillin, indicating that the ring sustains mechanical tension. Our work demonstrates that the ring is a site of tension, balancing protrusion at the core. This local coupling of opposing forces forms the basis of protrusion and reveals the podosome as a nanoscale autonomous force generator

Evidence from three-dimensional seismic tomography for a substantial accumulation of gas hydrate in a fluid-escape chimney in the Nyegga pockmark field, offshore Norway

In recent years, it has become evident that features commonly called gas chimneys provide major routes for methane to pass through the methane-hydrate stability zone in continental margins and escape to the ocean. One of many such chimneys lying beneath pockmarks in the southeastern Voring Plateau off Norway was investigated with a high-resolution seismic experiment employing a 2-D array of sixteen 4-component ocean bottom seismic recorders at approximately 100 m separation and a dense network of shots to define the 3-D variation of the chimney's structure and seismic properties. The tomographic model derived from P wave travel times shows that P wave velocity inside the chimney is up to 300 m/s higher than in the surrounding strata within the methane-hydrate stability zone. The zone of anomalously high velocity, about 500 m wide near its base, narrowing to about 200 m near the seabed, extends to a depth of 250 m below the seafloor. The depth extent of this zone and absence of high velocity beneath the base of the methane-hydrate stability field make it more likely that it contains hydrate rather than carbonate. If a predominantly fracture-filling model is appropriate for the formation of hydrate in low-permeability sediment, the maximum hydrate concentration in the chimney is estimated to be 14%-27% by total volume, depending on how host-sediment properties are affected by hydrate formation. Doming of the strata penetrated by the chimney appears to be associated with the emplacement of hydrate, accompanying the invasion of the gas hydrate stability zone by free gas