Zebrafish models for human acute organophosphorus poisoning

Terrorist use of organophosphorus-based nerve agents and toxic industrial chemicals against civilian populations constitutes a real threat, as demonstrated by the terrorist attacks in Japan in the 1990 s or, even more recently, in the Syrian civil war. Thus, development of more effective countermeasures against acute organophosphorus poisoning is urgently needed. Here, we have generated and validated zebrafish models for mild, moderate and severe acute organophosphorus poisoning by exposing zebrafish larvae to different concentrations of the prototypic organophosphorus compound chlorpyrifos-oxon. Our results show that zebrafish models mimic most of the pathophysiological mechanisms behind this toxidrome in humans, including acetylcholinesterase inhibition, N-methyl-D-aspartate receptor activation, and calcium dysregulation as well as inflammatory and immune responses. The suitability of the zebrafish larvae to in vivo high-throughput screenings of small molecule libraries makes these models a valuable tool for identifying new drugs for multifunctional drug therapy against acute organophosphorus poisoning

Toxic Effects of Copper and Cadmium on Fertilization Potency of Gametes of Pacific Oyster (Crassostrea gigas)

In the present study, the effects of copper (Cu) and cadmium (Cd) to the Pacific oyster Crassostrea gigas gametes were investigated. [...

Detection of environmental mutagens using the FACIM assay

International audienc

Modélisation des effets de la température et de l'oxygène sur la dynamique de la population de l'esturgeon européen utilisant la théorie du budget énergétique dynamique

International audienceEuropean sturgeon (Acipenser sturio) is an anadromous fish that breeds in rivers and which was previously found on most coasts of Europe. The last population of this species, nowadays listed as critically endangered, is reproducing in the Garonne basin near Bordeaux, south-west of France. In order to avoid extinction, the applied strategy since 1985 has been to release young fish into natural environment. These young individuals resulted from the assisted reproduction of wild and/or captive mature individuals. Recently recorded data in the Garonne basin show that in some sectors, where juveniles are likely to growth, summer temperatures have reached very high levels and water column has been hypoxic. Therefore, the combined influence of these factors on the young developmental stages needs to be assessed. The main goal of our project is to provide key information for improving the management of young fish release, especially age at release and release sites that maximize the fish survival. In this purpose, we will first calibrate a standard DEB model, based on the large dataset provided by the long term ex-situ stock breeding in our research institute. This model will firstly be used to evaluate the effect of temperature and oxygen on the survival rate of the first developmental stages. Other aspects of the life cycle will also be investigated, such as the link between maturity and the migration dynamics of the species and the impact of environmental conditions on eggs quality. The last part of our project will consist in the implementation of the standard DEB model within a pre-existing Individual Based Model (IBM) of the sturgeon population dynamics in the Garonne basin. This methodology will allow us to identify which individual traits are determinant in order to maximize the reinforcement of the sturgeon population in this basin

Genetic polymorphism and its potential relation to environmental stress in five populations of the European flounder Platichthys flesus, along the French Atlantic Coast

International audienceIn this study, new DNA markers were explored for the flounder . cDNA and genomic sequences of the genes encoding the glyceraldehyde-3-phosphate-deshydrogenase (GAPDH), the cytosolic creatine kinase (CK), the prostaglandin D synthase (PGDS) and the betain homocystein methyltransferase (BHMT) were characterized. The tumour suppressor p53 gene structure was already described. A PCR-SSCP () analysis was finally conducted to study the genetic polymorphism of different populations of flounders collected along the French Atlantic coast. Four highly contaminated French estuaries (Seine, Vilaine, Loire and Gironde) were sampled and compared to a reference estuary (Ster) to explore possible selective effect of the environment on specific allelic frequencies. Our results showed that two loci p53and PGDS, could be potential markers of chemical stress: p53A allele frequency increased in contaminated systems compared to the reference system. In the Vilaine estuary, PGDS polymorphism could be related to pesticide stress

Hypoxia tolerance of European sturgeon (Acipenser sturio L., 1758) young stages at two temperatures

International audienceEuropean sturgeon sensitivity to oxygen depletion at two different temperatures was evaluated with embryos from fertilization to hatching time that were exposed to 90% O2 saturation (% O2 sat), 50% O2 sat and 30% O2 sat at 20 and 26°C; and three-month-old juveniles (12 cm length, 7.3 g width) exposed to oxygen challenge from 70% O2 sat to 10% O2 sat at 20 and 25°C. Parameters measured included embryonic survival rate (ESR) and hatch rate (HR); in juvéniles the opercular beat frequency (OBF), altered swimming behavior, loss of equilibrium (LOE), and death were recorded. ESR did not differ between oxygen saturation levels for a single temperature but decreased between 20 and 26°C from 60.7 to 21.4% mean survival, respectively. No hatching was observed in embryos exposed to oxygen depletion at 50 and 30% O2 sat, regardless of temperature. The HR was lower at 26°C (15.4% mean) than at 20°C (75.8%) at 90% O2 sat. In embryos, all three oxygen concentrations allowed embryonic survival at the tested temperatures but were insufficient for increased activity such as hatching except at 20°C and 90% O2 sat. In juveniles, OBF peaked at 40% O2 sat at 212 beats per minute at 25°C and at 40–30% O2 sat at 182–183 beats per minute at 20°C. For LOE and death no significant differences were observed with regard to oxygen saturation at 20 and 25°C. Altered swimming behavior appeared at a significantly higher oxygen saturation at 25°C (43.5%) compared to 20°C (34.5%). Anaerobic metabolism was initiated after the OBF peak, which would represent a PO2crit for European sturgeon juveniles under 30 and 40% at 20°C and 25°C, respectively. Temperature increase also adversely affected the threshold of altered swimming behavior, which could be considered as a behavioral indicator of metabolic stress. The probability that the sturgeon embryos are being exposed to harmful temperatures and hypoxic conditions remains a true threat in the Gironde catchment basin

SturTOP project:Vulnerability and adaptability of the last population of the European Sturgeon (Acipenser sturio) to the environmental stress factors: Temperature, Oxygen, Polluants.

SturTOP is a multidisciplinary project launched in 2013 to investigate effects of chemical, thermal or hypoxic stress conditions on the health, the physiology, the behaviour and the adaptability of the first life stages of the European sturgeon. Experiments will be performed to evaluate responses of embryos and larvae exposed: i) in controlled conditions to environmental ranges of temperatures, oxygen and pollutant mixture, ii) to sediments collected from spawning grounds, iii) in situ. Studied effects will concern the individual fitness i.e. survival, ontogeny and behaviour as well as DNA damage, epigenetic modifications, gene expression and protein expression profiles. The same effects will be studied for 3 month-old farmed sturgeon (age of stocking) exposed in experimental systems which mimic the environmental conditions. In the wild, environmental exposure to pollutants will be evaluated thanks to individual dosimeters and to chemical analysis of stomach content. In a final step, a model will be built to simulate the future for a cohort subjected to multiple stresses. Expected results will give insights into the ability of this species to grow and to reproduce in the Gironde estuary and to adapt to changing environmental conditions. It could help decision-making by managers in charge of restoration plans

Embryotoxic and genotoxic effects of heavy metals and pesticides on early life stages of Pacific oyster (Crassostrea gigas)

International audienceThis study evaluated embryotoxicity and genotoxicity of two dissolved metals copper and cadmium (Cu and Cd) and two pesticides (metolachlor and irgarol) occurring in Arcachon Bay (SW France) in Pacific oyster (Crassostrea gigas) larvae and investigated the relationship between those two endpoints. Embryotoxicity was measured by calculating the percentage of abnormal D-shaped larvae and genotoxicity was evaluated with DNA strand breaks using the comet assay. After 24 h exposure, significant increases of the percentage of abnormal D-larvae and the DNA strand breaks were observed from 0.1µg/L for Cu, 10 µg/L for Cd and 0.01 µg/L for both irgarol and metolachlor in comparison with the controls. A strong positive relationship between embryotoxicity and genotoxicity was recorded for Cu, Cd and metolachlor. The current study suggests that copper, irgarol and metolachlor can induce larval abnormalities and DNA damage in a population of exposed oysters at environmentally relevant concentrations

La pollution plastique en estuaire de Seine : imprégnation environnementale, dynamique et impact sur le vivant

Le fascicule 3.7 « La pollution plastique en estuaire de Seine : dynamique, imprégnation environnementale et impact sur le vivant » propose une synthèse des travaux scientifiques menés ces dernières années sur la pollution micro et macroplastiques de l'estuaire de la Seine et une mise en perspective vis-à-vis d'autres acquisitions de données. Il s'attache à répondre aux questionnements suivants : Quelle est le niveau de pollution plastique, des larges débris jusqu'aux microplastiques, dans les différents compartiments environnementaux de l'estuaire de la Seine, à savoir les berges, la colonne d'eau, les fonds sédimentaires et les organismes aquatiques ? Quelles sont les dynamiques qui régissent le comportement des débris plastiques dans l'estuaire de la seine ? Quels sont les impacts des débris plastiques sur la faune aquatique de l'estuaire de la Seine