Pre-hatching fluoxetine-induced neurochemical, neurodevelopmental, and immunological changes in newly hatched cuttlefish
Embryonic and early postembryonic development of the cuttlefish Sepia officinalis (a cephalopod mollusk) occurs in coastal waters, an environment subject to considerable pressure from xenobiotic pollutants such as pharmaceutical residues. Given the role of serotonin in brain development and its interaction with neurodevelopmental functions, this study focused on fluoxetine (FLX), a selective serotonin reuptake inhibitor (SSRI, antidepressant). The goal was to determine the effects of subchronic waterborne FLX exposure (1 and 10 mu g L-1) during the last 15 days of embryonic development on neurochemical, neurodevelopmental, behavioral, and immunological endpoints at hatching. Our results showed for the first time that organic contaminants, such as FLX, could pass through the eggshell during embryonic development, leading to a substantial accumulation of this molecule in hatchlings. We also found that FLX embryonic exposure (1 and 10 mu g L-1) (1) modulated dopaminergic but not serotonergic neurotransmission, (2) decreased cell proliferation in key brain structures for cognitive and visual processing, (3) did not induce a conspicuous change in camouflage quality, and (4) decreased lysozyme activity. In the long term, these alterations observed during a critical period of development may impair complex behaviors of the juvenile cuttlefish and thus lead to a decrease in their survival. Finally, we suggest a different mode of action by FLX between vertebrate and non-vertebrate species and raise questions regarding the vulnerability of early life stages of cuttlefish to the pharmaceutical contamination found in coastal waters.
(Environmental Science and Pollution Research. vol. 23, n° 0944-1344, pp. 5030--5045, 01/03/2016)
GMPc, UNICAEN, NU, BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
First light of the VLT planet finder SPHERE II. The physical properties and the architecture of the young systems PZ Telescopii and HD 1160 revisited
Context. The young systems PZ Tel and HD 1160, hosting known low-mass companions, were observed during the commissioning of the new planet finder of the Very Large Telescope (VLT) SPHERE with several imaging and spectroscopic modes. Aims. We aim to refine the physical properties and architecture of both systems. Methods. We use SPHERE commissioning data and dedicated Rapid Eye Mount (REM) observations, as well as literature and unpublished data from VLT/SINFONI, VLT/NaCo, Gemini/NICI, and Keck/NIRC2. Results. We derive new photometry and confirm the short-term (P = 0.94 d) photometric variability of the star PZ Tel A with values of 0.14 and 0.06 mag at optical and near-infrared wavelengths, respectively. We note from the comparison to literature data spanning 38 yr that the star also exhibits a long-term variability trend with a brightening of similar to 0.25 mag. The 0.63-3.8 mu m spectral energy distribution of PZ Tel B (separation similar to 25 AU) allows us to revise its physical characteristics: spectral type M7 +/- 1, T-eff = 2700 +/- 100 K, log(g) \textless 4.5 dex, luminosity log(L/L-circle dot) = 2.51 +/- 0.10 dex, and mass 38 72 M-J from “hot-start” evolutionary models combining the ranges of the temperature and luminosity estimates. The 1-3.8 mu m SED of HD 1160 B (similar to 85 au) suggests a massive brown dwarf or a low-mass star with spectral type M6.0+1.00.5, T-eff = 3000 +/- 100 K, subsolar metallicity [M/H] = -0.5-0.0 dex, luminosity log(L/L-circle dot) = 2.81 +/- 0.10 dex, and mass 39 166 MJ. The physical properties derived for HD 1160 C (similar to 560 au) from KsL' -band photometry are consistent with the discovery study. The orbital study of PZ Tel B confirms its deceleration and the high eccentricity of its orbit (e \textgreater 0.66). For eccentricities below 0.9, the inclination, longitude of the ascending node, and time of periastron passage are well constrained. In particular, both star and companion inclinations are compatible with a system seen edge-on. Based on “hot-start” evolutionary models, we reject other brown dwarf candidates outside 0.25 `' for both systems, and giant planet companions outside 0.5 `' that are more massive than 3 MJ for the PZ Tel system. We also show that K1-K2 color can be used along with YJH low-resolution spectra to identify young L-type companions, provided high photometric accuracy (\textless= 0.05 mag) is achieved. Conclusions. SPHERE opens new horizons in the study of young brown dwarfs and giant exoplanets using direct imaging thanks to high-contrast imaging capabilities at optical (0.5-0.9 mu m) and near-infrared (0.95-2.3 mu m) wavelengths, as well as high signal-to-noise spectroscopy in the near-infrared domain (0.95-2.3 mu m) from low resolutions (R similar to 30 50) to medium resolutions (R similar to 350).
(Astronomy & Astrophysics - A&A. vol. 587, n° 0004-6361, 01/03/2016)
OAPD, INAF, IPAG, INSU - CNRS, CNES, CNRS, OSUG, Grenoble INP, INSU - CNRS, IRSTEA, USMB [Université de Savoie] [Université de Chambéry], CNRS, UGA [2016-2019], LAM, AMU, INSU - CNRS, CNES, CNRS, ESO, ESO, OACT, INAF, LESIA, UPMC, INSU - CNRS, CNRS, PSL, UPD7, CNRS, MPIA, ETH Zürich, UNIGE, UDP, DAS, UCHILE, AI PANNEKOEK, UvA, TUM, CRAL, ENS de Lyon, UCBL, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CALTECH, CFHT, INSU - CNRS, NRC, CNRS, UH, GSFC, MONARIS, UPMC, INC-CNRS, CNRS, ObsGE, UNIGE, LAGRANGE, UNS, INSU - CNRS, UniCA, CNRS, UniCA, ESRF, CREATIS, UCBL, INSA Lyon, INSA, UJM, INSERM, CNRS
In situ spawning in a marine broadcast spawner, the Pacific oyster Crassostrea gigas: Timing and environmental triggers
The precise environmental conditions under which broadcast spawners spawn in the field remain largely unknown. We investigated this issue in the oyster Crassostrea gigas using three different methods at different time scales in two traditional oyster farming areas of the French Atlantic Coast, the Bay of Arcachon and Marennes-Oléron. We directly recorded spawning at high temporal resolution using high-frequency non-invasive (HFNI) valvometry from 2007–2014 and measured the dry mass and oyster larvae abundance in 2008 and 2009. We analyzed a 29-yr series of oyster D-larvae numbers in the Bay of Arcachon (1982–2010). By combining these three approaches, we demonstrated that during the summer months at both sites, spawning in C. gigas occurs in the morning or during the evening, essentially at high tide of perigean spring tides, independent of the positions of these oysters, above or below the lowest water level. We characterized the associated water currents at the spawning location in the Bay of Arcachon and observed that spawning systematically occurs during the early phase of a water current peak, at the beginning of ebbing. We propose that this water current peak acts as a final trigger for spawning. These results have ecological consequences associated with gamete encounters and the dispersal of fertilized eggs (zygotes).
(Limnology and Oceanography. vol. 61, n° 0024-3590, pp. 635-647, 01/03/2016)
IFREMER, LEMAR, IRD, IFREMER, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Proteomic changes in Corbicula fluminea exposed to wastewater from a psychiatric hospital
The increase use of pharmaceutical compounds in veterinary practice and human population results in the ubiquitous presence of these compounds in aquatic ecosystems. Because pharmaceuticals are highly bioactive, there is concern about their toxicological effects in aquatic organisms. Therefore, the aim of this study was to assess the effects of an effluent from a psychiatric hospital (containing a complex mixture of 25 pharmaceutical compounds from eleven therapeutic classes) on the freshwater clam Corbicula fluminea using a proteomic approach. The exposure of C. fluminea to this complex effluent containing anxiolytics, analgesics, lipid regulators, beta blockers, antidepressants, antiepileptics, antihistamines, antihypertensives, antiplatelets and antiarrhythmics induced protein changes after 1 day of exposure in clam gills and digestive gland more evident in the digestive gland. These changes included increase in the abundance of proteins associated with structural (actin and tubulin), cellular functions (calreticulin, proliferating cell nuclear antigen (PCNA), T complex protein 1 (TCP1)) and metabolism (aldehyde dehydrogenase (ALDH), alcohol dehydrogenase, 6 phosphogluconate dehydrogenase). Results from this study indicate that calreticulin, PCNA, ALDH and alcohol dehydrogenase in the digestive gland and T complex protein 1 (TCP1)) and 6 phosphogluconate dehydrogenase in the gills represent useful biomarkers for the ecotoxicological characterization of psychiatric hospital effluents in this species.
(Environmental Science and Pollution Research. vol. 23, n° 0944-1344, pp. 5046-5055, 01/03/2016)
CIMA, UAlg, LECA, USMB [Université de Savoie] [Université de Chambéry], CNRS, UGA [2016-2019], IRIB, UNIROUEN, NU, INSERM, CNRS, HeRacLeS, UNIROUEN, NU, IRIB, UNIROUEN, INSERM, CNRS, INSERM, INC-CNRS, CNRS, BTSB, INUC, Comue de Toulouse, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GEODE, UT2J, Comue de Toulouse, CNRS, INUC, Comue de Toulouse
Differences between mono-generic and mixed diatom silicon isotope compositions trace present and past nutrient utilisation off Peru
In this study we combine for the first time silicon (Si) isotope compositions of small mixed diatom species (d 30 Si bSiO2) and of large handpicked mono-generic (i.e. genus = Coscinodiscus) diatom samples (d 30 Si Coscino) with diatom assemblages extracted from marine sediments in the Peruvian upwelling region in order to constrain present and past silicate utilisation. The extension of a previous core-top data set from the Peruvian shelf demonstrates that d 30 Si Coscino values record near-complete Si utilisation, as these are similar to the isotopic composition of the subsurface source waters feeding the upwelling. In contrast, the d 30 Si bSiO2 of small mixed diatom species increase southward along the shelf as well as towards the shore. We attribute highest d 30 Si bSiO2 values partly to transient iron limitation but primarily to the gradual increase of Si isotope frac-tionation within the seasonal diatom succession, which are mainly recorded by small diatom species during intense bloom events. In contrast, lower d 30 Si bSiO2 values are related to initial Si isotope utilisation during periods of weak upwelling, when low Si(OH) 4 concentrations do not permit intense blooms and small diatom species record substantially lower d 30 Si signatures. As such, we propose that the intensity of the upwelling can be deduced from the offset between d 30 Si bSiO2 and d 30 Si Coscino (D 30 Si coscino-bSiO2), which is low for strong upwelling conditions and high for prevailing weak upwelling. We apply the information extracted from surface sediments to generate a record of the present-day main upwelling region covering the past 17,700 years and find that this location has also been characterized by a persistent offset (D 30 Si coscino-bSiO2). By comparison with the diatom assemblages we show that the coastal upwelling system changed markedly between weak and strong upwelling conditions. In addition, our model calculations to quantify species-specific Si isotope fractionation effects based on the diatom assemblages indicate an overall minor influence that cannot explain the high amplitude in the measured d 30 Si bSiO2 record.
(Geochimica et Cosmochimica Acta. vol. 177, n° 0016-7037, pp. 30-47, 01/03/2016)
GEOMAR, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, RWTH Aachen, CAU
Sub-chronic exposure to fluoxetine in juvenile oysters (Crassostrea gigas): uptake and biological effects
The bioconcentration potential of fluoxetine (FLX) and its biological effects were investigated in juvenile Pacific oyster exposed for 28 days to environmentally relevant concentrations of FLX (1 ng L−1, 100 ng L−1 and up to 10 μg L−1). FLX bioaccumulated in oyster flesh resulting in 28-day bioconcentration factors greater than 2,000 and 10,000 by referring to wet and dry weights, respectively. Nevertheless, FLX did not induce oyster mortality, delayed gametogenesis, or lead to adverse histopathological alterations. At the two highest concentrations, despite non-optimal trophic conditions, FLX stimulated shell growth but only in a transient manner, suggesting a role of serotonin in the regulation of feeding and metabolism in bivalves. Those high concentrations seemed to drive bell-shaped responses of catalase and glutathione S-transferase activities throughout the exposure period, which may indicate the activation of antioxidant enzyme synthesis and then an enhanced catabolic rate or direct inhibition of those enzymes. However, no clear oxidative stress was detected because no strong differences in thiobarbituric acid-reactive substance (TBARS) content (i.e. lipid peroxidation) were observed between oyster groups, suggesting that cellular defence mechanisms were effective. These results demonstrate the importance of considering additional biomarkers of oxidative stress to obtain a comprehensive overview of the FLX-induced changes in marine bivalves exposed under realistic conditions. Considering the battery of biomarkers used, FLX appears to induce little or no effects on oyster physiology even at a concentration of 10 μg L−1. These results do not confirm the lowest observed effect concentration (LOEC) values reported by some authors in other mollusc species.
(Environmental Science and Pollution Research. vol. 23, n° 0944-1344, pp. 5002-5018, 01/03/2016)
GMPc, UNICAEN, NU, BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, LEFE, INEE-CNRS, CNRS, UT3, Comue de Toulouse, CNRS, Toulouse INP, Comue de Toulouse, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPTC, UB, CNRS
Swash Bar Effects On The Response Of A Large Barrier-Spit Terminus To Extreme Wave Climate: The Cap Ferret Example
The succession of severe storms in the North-Eastern Atlantic during the 2013-2014 winter has generated exceptional erosion along the Gironde coast (SW France). Meanwhile, at the Southern extremity of this 110-km long sandy coastal stretch, the Cap Ferret barrier-spit terminus remained relatively stable. The spit terminus is flanked by the Bay of Arcachon tidal inlet which generates strong tidal currents that help local waves to build massive swash bars. Such a bar is seen as the main explanation to the contrasting behaviour observed throughout the winter.
(01/03/2016)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
A coupled model for carbon and radiocarbon evolution during the last deglaciation
Changes in the ventilation of the Southern Ocean are thought to play an important role on deglacial carbon and radiocarbon evolution but have not been tested within a coupled climate-carbon model. Here we present such a simulation based on a simple scenario of transient deglacial sinking of brines-sea ice salt rejections-around Antarctica, which modulates Southern Ocean ventilation. This experiment is able to reproduce deglacial atmospheric changes in carbon and radiocarbon and also ocean radiocarbon records measured in the Atlantic, Southern, and Pacific Oceans. Simulated for the first time in a fully coupled climate-carbon model of intermediate complexity including radiocarbon, our modeling results suggest that the deglacial changes in atmospheric carbon dioxide and radiocarbon were achieved by means of a breakdown in the glacial brine-induced stratification of the Southern Ocean.
(Geophysical Research Letters. vol. 43, n° 0094-8276, pp. 1306-1313, 16/02/2016)
LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, CLIM, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Impact des polluants et du changement climatique sur les capacités de reproduction et le développement embryo larvaire de l’huître creuse Crassostrea gigas dans le Bassin d’Arcachon
L'huître creuse du Pacifique constitue une part importante de la production aquacole mondiale, avec 555 913 tonnes produites en 2013. La France est le quatrième producteur mondial d'huîtres et Crassostrea gigas est la principale espèce cultivée dans le bassin d'Arcachon. Cependant, ces dernières années, des problèmes de recrutement et de captage des naissains de certaines cohortes d’huîtres sont survenus. L'augmentation de la fréquence de ces événements peut être révélatrice de changements dans la qualité du milieu. Dans ce contexte de crise, ces travaux se sont intéressés à l’impact de deux polluants, le cuivre et le S-métolachlore, majoritairement retrouvés dans les eaux du Bassin d’Arcachon sur le développement embryo-larvaire des larves D de l’huître creuse (24h post -fécondation). Dans un contexte de changement climatique, une approche multifactorielle a été adoptée afin d’étudier les effets combinés des polluants et de l’accroissement des températures ou des changements de salinité susceptibles d’altérer le développement et la survie des embryons et des larves en période estivale. Dans un premier temps, les effets embryo-toxiques d’une pollution par le cuivre ou le S-métolachlore couplés ou non à la salinité ou à différentes températures ont été étudiés sur des huîtres en provenance d’une écloserie. Pour cela le test embryo-larvaire a été utilisé, et ses limites d’application précisées. Dans un deuxième temps, les effets des polluants couplés ou non à des températures et salinités environnementales ont été analysés sur les embryons provenant d’huîtres sauvages ou cultivées prélevées directement dans le milieu en différents sites du Bassin d’Arcachon. Le pourcentage de malformations ainsi que l’expression différentielle de gènes cibles ont été déterminés chez les larves tandis que la bioaccumulation du cuivre et du S-métolachlore et le pourcentage d’occupation gonadique ont été analysés chez les géniteurs. Ces résultats ont ensuite été comparés afin de déterminer la capacité des huîtres d’écloserie à représenter un modèle alternatif aux huîtres autochtones. Dans l’objectif d’étudier les impacts liés au changement climatique, des conditions un peu plus extrêmes ont été testées, à savoir des températures supérieures de 26 °C, des salinités inférieures de 24 u.s.i et des concentrations en polluants supérieures aux conditions actuelles du bassin. La mise au point d’un logiciel d’analyse du comportement natatoire des larves D a également été réalisée. Nos résultats indiquent une bioaccumulation plus grande du Cu et S-métolachlore dans les huîtres cultivées par rapport aux huîtres sauvages. Par ailleurs cette étude indique clairement que les larves issues des huîtres autochtones (sauvages et cultivées) sont sensibles à des concentrations environnementales en cuivre et en S-métolachlore. Cependant, il a été montré que les gènes impliqués dans divers mécanismes de défense sont surexprimés, avec une plus grande capacité de défense des larves issues des huîtres sous l’influence des tributaires mais également des huîtres sauvages par rapport aux cultivées. En présence de concentrations environnementales de Cu comme de S-métolachlore, une augmentation des trajectoires erratiques circulaires a été constatée. De plus, les larves, bien que capables de se développer normalement dans une gamme de températures allant de 22 °C à 26 °C, sont sensibles à l’action combinées des hautes/basses températures et des polluants. De la même manière, elles sont sensibles aux effets combinés de la dessalure et de l’exposition aux polluants. Les huîtres d’écloserie se sont révélées être une bonne alternative à l’utilisation des huîtres autochtones. Finalement, au vu des prédictions concernant l’évolution du climat, nos résultats indiquent qu’il faut s’attendre à un accroissement des malformations larvaires et donc à une diminution du recrutement des naissains dans les années futures dans le Bassin d’Arcachon.
(15/02/2016)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
How toxic is the depleted uranium to crayfish Procambarus clarkii compared with cadmium?
Due to a lack of information on the assessment of uranium's (U) toxicity, our work aimed to compare the effects of U on the crayfish Procambarus clarkii with those of the well documented metal cadmium (Cd). Accumulation and impacts at different levels of biological organization were assessed after acute (40 μM Cd or U; 4-10 days) and chronic (0.1 μM Cd or U; 30-60 days) exposures. The survival rates demonstrated the high tolerance of this species toward both metals and showed that Cd had a greater effect on the sustainability of crayfish. The concentration levels of Cd and U accumulated in gills and hepatopancreas were compared between both conditions. Distinctions in the adsorption capacities and the mobility of the contaminants were suspected. Differences in the detoxification mechanisms of both metals using transmission electron microscopy equiped with an energy dispersive X-ray were also pointed out. In contrast, comparison between the histological structures of contaminated hepatopancreas showed similar symptoms. Principal component analyses revealed different impacts of each metal on the oxidative balance and mitochondria using enzymatic activities and gene expression levels as endpoints. The observation that U seemed to generate more oxidative stress than Cd in our conditions of exposure is discussed. © 2014 Wiley Periodicals, Inc.
(Environmental Toxicology. vol. 31, n° 1520-4081, pp. 211-223, 01/02/2016)
IRSN/PRP-ENV/SERIS/L2BT, IRSN/PRP-ENV/SERIS, IRSN, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS