In addition to pollution, organisms are exposed to natural variations of the biotic and abiotic factors of their environment. A battery of sub-cellular biomarkers has been measured seasonally in ...several populations of both Dreissena polymorpha and Dreissena rostriformis bugensis. To observe and understand the variability associated with biomarker responses, water physicochemistry, sediment contamination, and internal concentrations of contaminants in soft tissues were also considered. Results evidenced seasonal, inter-specific, and inter-populational variability of the measured responses, highlighting the needs (1) to acquire long-term data on the studied populations and (2) to incorporate environmental parameters and contamination in the interpretation of biological responses. From a biomonitoring perspective, significant relationships were identified between biomarkers, internal concentrations of contaminants in soft tissues, and sediment contamination in D. r. bugensis and, to a lesser extent, in D. polymorpha. The detailed interpretation of each biomarker of the battery measured is complex, but a global analysis of all biomarkers at once allows to obtain this signature of the contamination of the studied sites.
Because they are widely used, copper oxide nanoparticles (CuO NPs) are likely to enter the aquatic environment and then reach the sediment. We have examined the effect of CuO NPs in the freshwater ...endobenthic bivalve Corbicula fluminea. Some previous studies have investigated effects at biochemical and physiological levels, but molecular endpoints are still poorly studied despite they are sensitive in early detection of NPs effect. In the present study, we have investigated short-term effects (96 h) of CuO NP (12, 30 nm; 0, 20 and 100 μg/L) using molecular endpoints as well as more conventional biochemical and physiological markers. The expression of antioxidant (CuZnSOD, MnSOD, Cat, Se-GPx, Trxr) and antitoxic (GST-Pi, HSP70, MT, Pgp, MRP1) related genes was measured at the mRNA level while antioxidant (SOD, TAC) and antitoxic (GST, ACP) defenses, energetic reserves and metabolism (ETS, Tri, LDH), and cellular damages (LPO) were assessed using a biochemical approach. The filtration rate measured at 96 h provided information at the physiological scale. Gene expression and filtration rate were responsive to CuO NPs but the effects differed according to the NP size. The results suggest that defense mechanisms may have been set up following 30 nm-NP exposure. The response to 12 nm-NP was lower but still showed that exposure to 12 nm-NP led to activation of cellular elimination mechanisms. The lowering of the filtration rate may have protected the organisms from the contamination. However, this raised the question of further repercussions on organism biology. Together, the results (i) indicate that CuO NP may exert effects at different levels even after a short-term exposure and (ii) point out the precocity of molecular response.
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•CuO NP of two sizes induced short-term responses in C. fluminea.•Anti-toxic defense and cellular elimination related mRNAs have been increased.•The molecular approach suggests a mechanism of action dependent on NP size.•The clams may avoid exposure by reducing filtration, preventing from Cu accumulation.•Biochemical markers have not been responsive to the exposure.
The short-term exposure of Corbicula fluminea to CuO NPs (12 & 30 nm) altered gene expression of cellular defense in the digestive gland and decreased filtration rate.
Chromium has two main oxidation states, Cr(III) and Cr(VI), that can occur simultaneously in natural waters. Current consensus holds that Cr(VI) is of high ecotoxicological concern, but regards ...Cr(III) as poorly bioavailable and relatively non-toxic. In this work, the effects and bioaccumulation of Cr(III), Cr(VI) and their mixture were studied using the freshwater clam Corbicula fluminea as a model organism. Mixture exposures were carried out using solutions isotopically enriched in 50Cr(III) or 53Cr(VI), allowing to quantify the contribution of each redox form to total Cr accumulation in the clams. Following exposure to individual redox forms, Cr(III) accumulated preferentially in the digestive glands and Cr(VI) in the gills of C. fluminea. In mixture exposures, both redox forms accumulated mainly in the gills; the concentration of Cr(III) in the digestive glands being much lowered compared with individual exposures. Both oxidation states affected the expression of biomarkers related to energy reserves, cellular damage and mitochondrial functioning, as well as the expression of mRNA for detoxification genes. The observed effects differed between gills and digestive glands. The present study suggests that Cr(III) is a bioavailable and biologically active elemental species deserving more consideration by the ecotoxicological community.
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•Biomarkers expression responds to Cr redox state, concentration and exposure duration.•First use of isotopically enriched solutions to study Cr(III)/Cr(VI) mixtures.•Both Cr(VI) and Cr(III) accumulate in gills and digestive glands of Corbicula fluminea.•The presence of Cr(VI) changes the accumulation pattern of Cr(III).•Cr(III) is a biologically active species along with Cr(VI).
•Biomarker responses in sympatric dreissenid populations were studied.•Impact of diverse stressors was assessed both in the field and in laboratory.•Different biomarker responses were observed ...between species and populations.•These differences are probably related to invasion dynamics and local adaptation for both species.•Some advices are provided concerning the use of these species for biomonitoring. purpose.
Dreissenid mussels, well-known invaders of the northern hemisphere, also constitute good biomonitors for freshwater quality assessment. Whereas the oldest, Dreissena polymorpha, is relatively well-known, the new invasive, Dreissena rostriformis bugensis, has been very little characterized. The aim of this study was to compare subcellular biomarker responses within these species, by taking into account inter- and intra-specific variability in biomarker responses during a multi-stress assessment. Indeed, due to local environmental conditions and genetic background, biomarker responses can be different between populations of a given species, not only between species. To evaluate these differential responses, we sampled mussels on two sites where they are both present in sympatry (plus another D. r. bugensis population), and we exposed these populations in laboratory to different stressors: thermal stress (12 or 17 °C), dietary stress (fed or unfed), contamination (nickel at 0, 20 and 500 μg L−1) and exposure duration (0, 4 or 8 days). Results mainly evidenced strong inter-species and inter-population differences, underlining the need to discriminate correctly between the two species and to know well the populations used in biomonitoring. Results also evidenced thermal and food stress-related effects. The numerous data obtained during this multi-stress experiment also highlight the complexity of working on several stressors and analysing the associated results.
Die Wallfahrtskirche Notre-Dame-Du-Haut in Ronchamp (1950-54), Ikone der modernen Architektur, stellt einen der zentralen Bauten in Le Corbusiers Spätwerk dar. Auf einem Hochplateau der Vogesen ...oberhalb Belforts gelegen, ist dieser Bau ein in Raum- und Formgestaltung einzigartiges Kunstwerk, das sich einmalig in seine Umgebung einpaßt. Das muschelförmige Dach, die gerundeten Mauern, die Türme aus Steinmauerwerk sowie die durch farbige Glasöffnungen rhythmisierte Fassade sind wesentliche Bestandteile dieser skulpturalen Konstruktion. Die Kapelle von Ronchamp ist in ihren Maßstäben und Proportionen nach dem von Le Corbusier entwickelten "Modulor" entworfen und erhält auch von daher ihre besondere räumliche Wirkung. Wie alle Guides dieser Reihe ist das Buch sowohl für das Fachpublikum als auch für an Architektur und moderner Kunst interessierte Touristen unentbehrlich. Es eignet sich zudem als apartes Geschenkbuch.
La chapelle de pèlerinage Notre-Dame-Du-Haut à Ronchamp (1950-1954), emblème de l'architecture moderne, représente une des réalisations clés de Le Corbusier sur la fin de sa carrière. Situé dans les ...Vosges, sur une colline dominant Belfort, cet édifice est une œuvre d'art unique en son genre par le traitement de la forme et de l'espace, qui se fond de manière extraordinaire dans son environnement. Le toit en forme de conque, les murs courbes, les tours en maçonnerie de pierre ainsi que la façade rythmée par des baies vitrées colorées sont des composants essentiels de cette construction sculpturale. Comme tous les guides de cette collection, cet ouvrage est un incontournable pour les spécialistes ainsi que pour les touristes s'intéressant à l'architecture et à l'art moderne. C'est aussi un cadeau original.
The pilgrimage church Notre-Dame-du-Haut in Ronchamp (1950-54), an icon of modern architecture, represents one of the central buildings of Le Corbusier's late period. Located on a high plateau in the ...Vosges above Belfort, this building is an unsurpassed work of art which also fits uniquely into its physical surroundings. The shell-shaped roof, the rounded walls, the towers of stone masonry, and the facade with its rhythmic openings of colored glass are the essential elements of this sculptural construction. The scale and proportions of the chapel at Ronchamp are designed on the basis of the Modulor that Le Corbusier developed, which accounts for its distinctive spatial effect. Like all the guides in this series, this book is indispensable both for a specialist audience and for tourists interested in architecture and modern art.
In this study, the performance of a new most probable number (MPN) test (Pseudalert(®)/Quanti-Tray(®)) for the enumeration of Pseudomonas aeruginosa from hospital waters was compared with both ...international and national membrane filtration-based culture methods for P. aeruginosa: ISO 16266:2006 and UK The Microbiology of Drinking Water - Part 8 (MoDW Part 8), which both use Pseudomonas CN agar. The comparison based on the calculation of mean relative differences between the two methods was conducted according to ISO 17994:2014. Using both routine hospital water samples (80 from six laboratories) and artificially contaminated samples (192 from five laboratories), paired counts from each sample and the enumeration method were analysed. For routine samples, there were insufficient data for a conclusive assessment, but the data do indicate at least equivalent performance of Pseudalert(®)/Quanti-Tray(®). For the artificially contaminated samples, the data revealed higher counts of P. aeruginosa being recorded by Pseudalert(®)/Quanti-Tray(®). The Pseudalert(®)/Quanti-Tray(®) method does not require confirmation testing for atypical strains of P. aeruginosa, saving up to 6 days of additional analysis, and has the added advantage of providing confirmed counts within 24-28 hours incubation compared to 40-48 hours or longer for the ISO 16266 and MoDW Part 8 methods.
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