45 research outputs found
Locomotion behavior of juveniles of the freshwater pearl mussel Margaritifera margaritifera: A new non-invasive tool for the evaluation of stress effects
International audienc
Evaluation des effets écotoxiques des rejets de STEP sur embryons de truite fario (Salmo trutta fario) encagés in situ
International audienc
Experimental ingestion of fluorescent microplastics by pacific oysters, Crassostrea gigas, and their effects on the behaviour and development at early stages
International audienc
An environmentally realistic pesticide and copper mixture impacts embryonic development and DNA integrity of the Pacific oyster, Crassostrea gigas
International audienc
Sub-lethal effects of waterborne copper in early developmental stages of rainbow trout (Oncorhynchus mykiss)
International audienceThe aim of this work was to study the impact of copper during a sub-chronic exposure to environmental concentrations in the early life stages of rainbow trout (Oncorhynchus mykiss). Eyed-stage embryos of rainbow trout, at 265°D, were exposed in semi-static conditions to sublethal concentrations of CuSO4 up to the larval stage (528 °D) under laboratory-controlled conditions. During 3 weeks, they were exposed to the environmentally-realistic concentration of 2 ”g/L Cu and to a 10-fold higher concentration, 20 ”g/L Cu. Several biological (survival, hatching success, malformation, growth) and behavioral (swimming activity) and molecular endpoints (genotoxicity and gene transcription) were studied. Exposure to 20 ”g/L Cu had an inhibitory effect on hatching and increased half-hatched embryos (25%). At the end of the exposure, no significant differences were observed in growth of the larvae exposed to the highest Cu concentration. However, larvae exposed to 2 ”g/L Cu exhibited increased growth in comparison with non-exposed larvae. The percentage of malformed larvae was significantly higher for both copper conditions, with skeletal malformations being the most observed. Expression of several genes was evaluated in whole larvae using quantitative real-time PCR. Genes involved in detoxification (gst, mt1 and mt2) and in cell cycle arrest (p53) were significantly repressed in both copper conditions when compared to control. In addition, potential genotoxic effects on larvae were investigated by the comet assay on blood cells, but this test did not demonstrate any significant DNA damage on larvae exposed to copper. This study confirms the adverse effects of copper on early life stages of rainbow trout even at the lowest environmentally relevant tested concentration
An environmentally realistic pesticide and copper mixture impacts embryonic development and DNA integrity of the Pacific oyster, Crassostrea gigas
International audienceFrequent occurrences of pesticides in the environment have raised concerns that combined exposure to these chemicals may result in enhanced toxicity through additive or synergistic interaction between compounds. Spermatozoa and embryos of the Pacific oyster, Crassostrea gigas, were exposed to different concentrations of a pesticide mixture with and without copper, mimicking the cocktail of pollutants occurring in the oyster culture area of Arcachon Bay. For the 1Ă exposure condition, measured concentration corresponds to a total concentration of 1.083 ÎŒg Lâ1 for the mixture of 14 pesticides and to 6.330 ÎŒg Lâ1 for copper (Cu). Several endpoints including larval abnormalities, DNA damage to spermatozoa and embryo and gene expression in D-larvae were investigated. Results demonstrated that pesticide mixtures in combination with or without copper induced a dose-dependent increase in embryotoxic and genotoxic effects on D-larvae from the lowest tested dose of 0.1Ă. Transcription of genes involved in anti-oxidative stress (cat), respiratory chain (coxI), metal detoxification (mt1 and mt2), and cell cycle arrest and apoptosis (p53) was found to be significantly downregulated while the xenobiotic biotransformation gene gst was significantly upregulated in embryos exposed to pesticide mixture with and without Cu. These findings raise the question of the possible impacts of mixtures of pesticides and metals on wild or farmed oyster populations from polluted coastal marine areas
Compared responses to copper and increased temperatures of hybrid and pure offspring of two mussel species
Psychotropic drugs in mixture alter swimming behaviour of Japanese medaka (Oryzias latipes) larvae above environmental concentrations
International audiencePsychiatric pharmaceuticals, such as anxiolytics, sedatives, hypnotics and antidepressors, are among the most prescribed active substances in the world. The occurrence of these compounds in the environment, as well as the adverse effects they can have on non-target organisms, justifies the growing concern about these emerging environmental pollutants. This study aims to analyse the effects of six psychotropic drugs, valproate, cyamemazine, citalopram, sertraline, fluoxetine and oxazepam, on the survival and locomotion of Japanese medaka Oryzias latipes larvae. Newly hatched Japanese medaka were exposed to individual compounds for 72 h, at concentrations ranging from 10 ÎŒg Lâ1 to 10 mg Lâ1. Lethal concentrations 50 % (LC50) were estimated at 840, 841 and 9,136 ÎŒg Lâ1 for fluoxetine, sertraline and citalopram, respectively, while other compounds did not induce any significant increase in mortality. Analysis of the swimming behaviour of larvae, including total distance moved, mobility and location, provided an estimated lowest observed effect concentration (LOEC) of 10 ÎŒg Lâ1 for citalopram and oxazepam, 12.2 ÎŒg Lâ1 for cyamemazine, 100 ÎŒg Lâ1 for fluoxetine, 1,000 ÎŒg Lâ1 for sertraline and >10,000 ÎŒg Lâ1 for valproate. Realistic environmental mixture of the six psychotropic compounds induced disruption of larval locomotor behaviour at concentrations about 10- to 100-fold greater than environmental concentrations
Response of zebrafish and Japanese medaka to imidacloprid: a comparative study
International audienceNeonicotinoids are among the most produced and used insecticides and are frequently found in freshwater with concentrations ranging from ng to ÎŒg/L. These molecules are small and very soluble in water. This given, they are likely to pass the chorion and thus easily enter embryos of fish. It is known that these compounds impact on insects, including bees, in terms of toxicity and behaviour, but whether similar impacts could be observed in fish is not yet known. The aim of this study was to investigate effects of exposure to imidacloprid, one of the most used neonicotinoids, on the development and behaviour of two common fish lab species: Zebrafish (Danio rerio) and Japanese medaka (Oryzias latipes). Fish were exposed during 5 (zebrafish) and 13 days (medaka) to 0, 0.2, 2, 20, 200 and 2000 ÎŒg/L imidacloprid by aqueous exposure, matching the respective time from fertilization to emerged larvae for the two species. At similar developmental stages, survival, hatch, growth, morphology, behaviour and histology were examined. No impact on survival was found. A delay for 2 ÎŒg/L imidacloprid exposures was observed for hatch in both species. Except for the 20 mg/L exposure level, imidacloprid led to hypoactivity in both species. A striking difference was found in morphology: a high number of deformities were noticed for medaka whereas almost none were found in zebrafish. Yolk and bone oedemas started to be noticed at 20 ÎŒg/L after hatch, jaw deformity and lordosis/scoliosis increased with concentration level. An increase of haemorrhage was found at the highest concentration (2000 ÎŒg/L). In order to shed light on the observed species differences, we intend to investigate the uptake of imidacloprid into the fish embryos and its biotransformation
Existe-t-il un transfert trophique des MP et quels sont les effets toxiques chez les larves et les juvéniles de soles ?
International audienceIntroduction En raison dâune forte pression anthropique, les zones estuariennes sont touchĂ©es par une importante pollution aux microplastiques (MP) et les espĂšces infĂ©odĂ©es Ă ces zones y sont particuliĂšrement exposĂ©es. Lâobjectif de cette Ă©tude, financĂ©e par le programme Seine-Aval, est dâĂ©valuer les effets de MP environnementaux collectĂ©s en estuaire de Seine sur une espĂšce emblĂ©matique de nos cĂŽtes, la sole commune (Solea solea) Ă travers une exposition directe ou par voie trophique. Exposition Deux types dâexpositions ont Ă©tĂ© rĂ©alisĂ©s. La premiĂšre est une exposition directe de larves de sole Ă plusieurs plastiques industriels de diffĂ©rentes tailles et densitĂ©s (27-35 ÎŒm et d=0.99 ; 27-32 ÎŒm et d=1.20 ; 63-75 ÎŒm et d=1.20) ainsi quâĂ un cocktail d'Ă©chantillons environnementaux prĂ©levĂ©s dans lâestuaire de la Seine (100 ÎŒm) afin de dĂ©terminer la cinĂ©tique d'ingestion et d'Ă©gestion. Pour mettre en Ă©vidence d'Ă©ventuelles diffĂ©rences en fonction du stade de dĂ©veloppement, cette exposition a Ă©tĂ© rĂ©alisĂ©e avant (7 jours post Ă©closion, jpe), pendant (21-22 jpe) et aprĂšs la mĂ©tamorphose (41-42 jpe). Dans une seconde expĂ©rience, des juvĂ©niles de sole ont Ă©tĂ© nourris avec des vers estuariens (Hediste diversicolor) prĂ©alablement exposĂ©s au MP via le sĂ©diment. Comme prĂ©cĂ©demment les MP utilisĂ©s sont dâorigines industrielles ou d'estuaire de Seine. Plusieurs marqueurs dâĂ©tat de santĂ© tels que la survie, la croissance, le comportement, le mĂ©tabolisme Ă©nergĂ©tique, le systĂšme immunitaire, le systĂšme digestif ont Ă©tĂ© Ă©tudiĂ©s. RĂ©sultats Quelque soit le stade de dĂ©veloppement, les larves ont ingĂ©rĂ©s tous les plastiques indĂ©pendamment de la taille et/ou du type et aucune diffĂ©rence de cinĂ©tique d'ingestion ou d'Ă©gestion n'a Ă©tĂ© mise en Ă©vidence. Pendant la mĂ©tamorphose le comportement natatoire des larves de sole a Ă©tĂ© modifiĂ© : la distance parcourue est plus faible chez les larves ayant consommĂ© des MP et pour tous les MP testĂ©s. Chez les juvĂ©niles de soles nourris avec des vers exposĂ©s Ă des MP environnementaux (400 ÎŒm) ou industriels (100-250 ÎŒm) nous avons mis en Ă©vidence une modification de comportement dans le choix du sol proposĂ© (noir ou blanc) et de couleur des individus exposĂ©s pour la concentration la plus haute et les MP enrobĂ©s de Benzo(a)PyrĂšne ou dâOxybenzone. Ces observations sont indicatrices d'un stress physiologiques. Ces premiers rĂ©sultats mettent en Ă©vidence les effets dĂ©lĂ©tĂšres des microplastiques lors d'expositions directes ou indirectes Ă diffĂ©rents stades de vie. Ce travail sera complĂ©tĂ© par une exposition de larves de soles pendant 1 mois Ă partir de l'Ă©closion Ă des copĂ©podes (Acartia tonsa) ayant eux-mĂȘmes Ă©tĂ© exposĂ©s Ă des MP