Tritium, a radioactive isotope of hydrogen of natural and anthropogenic origin, is ubiquitously p... more Tritium, a radioactive isotope of hydrogen of natural and anthropogenic origin, is ubiquitously present in the environment. Effluents of nuclear center of production are significant anthropogenic sources. With the upcoming project of thermonuclear fusion, tritium releases in the environment may increase. It is therefore important to characterize the ecological risk linked to tritium. The effects of tritiated water (HTO) were therefore studied in zebrafish larvae exposed during 10 days to different dose rates: 1.1x10 2 , 4.1x10 2 and 3.8x10 3 µGy/h for larvae, corresponding respectively to a water contamination of 10 4 , 10 5 and 10 6 Bq/mL of HTO. Those dose rates were higher than 10 μGy/h which is the threshold recommended to start monitoring ecosystems where radiological contaminants are present. Mortality, embryolarval development, immune-, geno and neuro-toxicity, and alterations of tissues were investigated. Results showed that tritiated water exposure induced DNA damage, ROS production and modulated the expression of genes involved in detoxification processes. Moreover, modifications of the muscular tissues (degradation of myofibrils at 4 dpf and disorganization of mitochondria at later stages) were observed. Results differed with HTO dose rates and with developmental stages. These results will drive future research for the development of new HTO-sensitive biomarkers and will allow us to progress in the characterization of the modes of action of tritium in fish.
The objective was to investigate the effects of ionizing radiation induced in zebrafish early lif... more The objective was to investigate the effects of ionizing radiation induced in zebrafish early life stages by coupling responses obtained at the molecular (genotoxicity, ROS production, gene expression) and phenotypic (tissue alteration, embryo-larval development) levels. Here we present results obtained after exposure of 3 hpf larvae to 10 days of gamma irradiation at 3.3 × 101, 1.3 × 102 and 1.2 × 103 µGy/h, close to and higher than the benchmark for protection of ecosystems towards ionizing radiations of 101 µGy/h. Dose rates used in these studies were chosen to be in the 'derived consideration reference level' (DCRL) for gamma irradiation where deleterious effects can appear in freshwater fish. Also, these dose rates were similar to the ones already tested on tritium (beta ionizing radiation) in our previous work, in order to compare both types of ionizing radiation. Results showed that gamma irradiation did not induce any effect on survival and hatching. No effect was observed on DNA damages, but ROS production was increased. Muscle damages were observed for all tested dose rates, similarly to previous results obtained with tritium (beta ionizing radiation) at similar dose rates. Some molecular responses therefore appeared to be relevant for the study of gamma ionizing radiation effects in zebrafish.
This study aimed to determine uranium (U) pollution over time using otoliths as a marker of fish ... more This study aimed to determine uranium (U) pollution over time using otoliths as a marker of fish U contamination. Experiments were performed in field contamination (~20 μg L−1: encaged fish: 15d, 50d and collected wild fish) and in laboratory exposure conditions (20 and 250 μg L−1, 20d). We reported the U seasonal concentrations in field waterborne exposed roach fish (Rutilus rutilus), in organs and otoliths. Otoliths were analyzed by ICPMS and LA-ICP SF MS of the entire growth zone. Concentrations were measured on transects from nucleus to the edge of otoliths to characterize environmental variations of metal accumulation. Results showed a spatial and temporal variation of U contamination in water (from 51 to 9.4 μg L−1 at the surface of the water column), a high and seasonal accumulation in fish organs, mainly the digestive tract (from 1000 to 30,000 ng g−1, fw), the gills (from 1600 to 3200 ng g−1, fw) and the muscle (from 144 to 1054 ng g−1, fw). U was detected throughout the otolith and accumulation varied over the season from 70 to 350 ng g−1, close to the values measured (310 ng g−1) after high exposure levels in laboratory conditions. U in otoliths of encaged fish showed rapid and high U accumulation from 20 to 150 ng g−1. The U accumulation signal was mainly detected on the edge of the otolith, showing two U accumulation peaks, probably correlated to fish age, i.e. 2 years old. Surprisingly, elemental U and Zn signatures followed the same pattern therefore using the same uptake pathways. Laboratory, caging and field experiments indicated that otoliths were able to quickly accumulate U on the surface even for low levels and to store high levels of U. This study is an encouraging first step in using otoliths as a marker of U exposure. Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site.
An overall criterion for protecting freshwaters against uranium chemo-toxicity should encompass a... more An overall criterion for protecting freshwaters against uranium chemo-toxicity should encompass all the compartments of the freshwater environment at risk (water column, sediment, predators, and humans). According to the latest European recommendations, we revised the interim Environmental Quality Standard currently applicable in France, to introduce physico-chemical parameters affecting uranium bioavailability in water and therefore toxicity, by using chemical speciation modelling in aqueous phase including both mineral ligands and organic mat-ter. Additionally, we completed the poor available data set related to sediment toxicity by implementing dedicated standardized tests and we explored the question of secondary poisoning. Human health was also briefly considered, to fulfill the methodological requirements.
h i g h l i g h t s Screening of U distribution among proteins in gill cytosols of U exposed zebr... more h i g h l i g h t s Screening of U distribution among proteins in gill cytosols of U exposed zebrafish. Significant U bioaccumulation in gills after 3 d of realistic chronic exposure. Different U-protein distribution patterns in cytosols as function of exposure level. Higher amount of U in the cytosolic fraction in case of high exposure level. Potential effect of U on Zn cytosolic burden.
Pollutants that occur at sublethal concentrations in the environment may lead to chronic exposure... more Pollutants that occur at sublethal concentrations in the environment may lead to chronic exposure in aquatic organisms. If these pollutants bioaccumulate, then organisms higher in the food chain may also be at risk. Increased attention has thus been focused on the relative importance of dietary uptake, but additional knowledge of the cellular distribution of metals after dietary exposure is required to assess the potential toxicity. The authors address concerns relating to increasing uranium (U) concentrations (from 12 µg/L to 2 mg/L) in the freshwater ecosystem caused by anthropogenic activities. The objective of the present study is to compare uranium bioaccumulation levels in tissues and in the subcellular environment. The authors focused on the cytosol fraction and its microlocalization (TEM-EDX) in the gills and the hepatopancreas (HP) of the crayfish Orconectes limosus after 10 d of direct exposure (at concentrations of 20, 100, and 500 µg/L) and five trophic exposure treatments (at concentrations from 1 to 20 µg/g). Results indicated that adsorption of uranium on the cuticle represents the main contribution of total uranium accumulation to the animal. Accumulation in the gills should be considered only as a marker of waterborne uranium exposure. Accumulation in the HP after trophic environmental exposure conditions was higher (18.9 ± 3.8 µg/g) than after direct exposure. Moreover, no significant difference in the subcellular distribution of uranium (50%) in HP was observed between animals that had been exposed to both types of treatment. A potential toxic effect after uranium accumulation could therefore exist after trophic exposure. This confirms the need to focus further studies on the metal (uranium) risk assessment.
This work aims to investigate the accumulation levels and effects (transcriptional responses, his... more This work aims to investigate the accumulation levels and effects (transcriptional responses, histopathology and survival rate) associated with a wide range of dissolved uranium (U) concentrations (0, 0.03, 0.6, 4 and 8 mg/L of U) on adult male crayfish Procambarus clarkii during 4 (T4) and 10 (T10) days of exposure. The follow-up of the crayfish mortality showed that P. clarkii was highly resistant to U. Increasing waterborne U concentrations led to increasing bioaccumulation in key crayfish organs and increasing histological damages. U distribution in tissues was also evaluated using transmission electron microscopy and showed the presence of a detoxified form of U in the gill's epithelium in the shape of flakes. Expression levels of mitochondrial genes (cox1, atp6 and 12S gene) and genes involved in oxidative stress (sod(Mn) and mt) were examined together with the housekeeping gene 18S. atp6 and mt genes of P. clarkii were cloned and sequenced before analysis. Significant correlations were observed between U bioaccumulation and the down-regulation of both cox1 and sod(Mn) genes. This work provides a first U toxicogenomic and histopathological pattern of P. clarkii, identify U biomarkers and associate gene expression endpoints to accumulation levels. It also provides new insights into the mechanisms involved in U stress.
Tritium (H) is a radioactive isotope of hydrogen. In the environment, the most common form of tri... more Tritium (H) is a radioactive isotope of hydrogen. In the environment, the most common form of tritium is tritiated water (HTO). The present study aimed to identify early biomarkers of HTO contamination through the use of an aquatic model, the zebrafish (Danio rerio). We used the zebrafish embryo-larvae model to investigate the modes of action of HTO exposure at dose rates of 0.4 and 4 mGy/h, dose rates expected to induce deleterious effects on fish. Zebrafish were exposed to HTO from 3 hpf (hours post fertilization) to 96 hpf. The transcriptomic effects were investigated 24 h and 96 h after the beginning of the contamination, using mRNAseq. Results suggested an impact of HTO contamination, regardless of the dose rate, on genes involved in muscle contraction (tnnt2d, tnni2a.4, slc6a1a or atp2a1l) and eye opacity (crygm2d9, crygmxl1, mipb or lim2.3) after 24 h of contamination. Interestingly, an opposite differential expression was highlighted in genes playing a role in muscle contrac...
Aquatic toxicology (Amsterdam, Netherlands), Jan 30, 2017
This study investigated the accumulation pattern and biological effects (genotoxicity and histopa... more This study investigated the accumulation pattern and biological effects (genotoxicity and histopathology) to adult zebrafish (male and female) exposed to a nominal waterborne concentration of 20 μg Lof depleted uranium (DU) for 28 days followed by 27 days of depuration. Accumulation pattern showed that (i) DU accumulated in brain, (ii) levels in digestive tract were higher than those measured in gills and (iii) levels remained high in kidney, brain and ovary despite the 27 days of depuration period. Genotoxicity, assessed by comet assay, was significant not only during DU exposure, but also during depuration phase. Gonads, in particular the testes, were more sensitive than gills. The histology of gonads indicated severe biological damages in males. This study improved knowledge of ecotoxic profile of uranium, for which a large range of biological effects has already been demonstrated.
A non-denaturating isoelectric focusing (ND-IEF) gel electrophoresis protocol has been developed ... more A non-denaturating isoelectric focusing (ND-IEF) gel electrophoresis protocol has been developed to study and identify uranium (U)-protein complexes with laser ablationinductively coupled plasma mass spectrometry (LA-ICP MS) and electrospray ionization mass spectrometry (ESI-MS). The ND-IEF-LA-ICP MS methodology setup was initiated using in vitro U-protein complex standards (i.e., U-bovine serum albumin and U-transferrin) allowing the assessment of U recovery to 64.4±0.4 %. This methodology enabled the quantification of U-protein complexes at 9.03±0.23, 15.27±0.36, and 177.31±25.51 nmol U L −1 in digestive gland cytosols of the crayfish, Procambarus clarkii, exposed respectively to 0, 0.12, and 2.5 μmol of waterborne depleted U L −1 during 10 days. ND-IEF-LA-ICP MS limit of detection was 19.3 pmol U L −1. Elemental ICP MS signals obtained both in ND-IEF electropherograms and in size exclusion chromatograms of in vivo U-protein complexes revealed interactions between U-and Fe-and Cu-proteins. Moreover, three proteins (hemocyanin, pseudohemocyanin-2, and arginine kinase) out of 42 were identified as potential uranium targets in waterborne-exposed crayfish cytosols by microbore reversed phase chromatography coupled to molecular mass spectrometry (µRPC-ESI-MS/MS) after ND-IEF separation.
At present, ecotoxicological information regarding the impact of natural uranium (U) on freshwate... more At present, ecotoxicological information regarding the impact of natural uranium (U) on freshwater ecosystems via the trophic contamination route is scarce. We generated an experimental trophic food chain involving the prey species, Corbicula fluminea, and a predator, Orconectes limosus, for a 10-day and a 30-day feeding periods (food ration: one whole soft body/day/crayfish). We studied the efficiency of U trophic transfer and the distribution of U in the predator. During the test, we varied the quantity of dietary U (from beforehand contaminated bivalves at concentrations ranging from 0.9 ± 0.1 to 20.2 ± 9 g/g fw provided to each crayfish over the 10 days) applying a daily feeding rate equal to 3.9 ± 0.8% fw. The efficiency of U trophic transfer from clams to crayfish varied between 1 and 13% depending on the prey exposure modalities. Accumulation of U was observed in the digestive gland but also in gills, in the muscle, and in the molt of the crayfish after trophic exposure treatments. Under high-level exposure conditions, the digestive gland was the main target-organ, however a significant accumulation was also observed in the stomach. With regard to low levels of trophic exposure, accumulation of U in gills, in the stomach, and in the digestive gland was of the same order of magnitude. Longer exposure period which incorporated a crayfish molt, resulted in a decrease of trophic transfer ratio and a modified U tissue distribution.
Environmental toxicology and chemistry / SETAC, Jan 17, 2015
New data on the nature of the protein targets of U within the zebrafish gills were collected afte... more New data on the nature of the protein targets of U within the zebrafish gills were collected after waterborne exposure to better understand uranium (U) toxicity mechanisms. This study evidenced some common characteristics of the U protein target binding properties such as their role in other essential metals regulation and their phosphorus content. In total 21 potential protein targets, including hemoglobin, were identified and discussed regarding the literature. This article is protected by copyright. All rights reserved.
The zebrafish, Danio rerio (Hamilton, 1822) has been widely used as a vertebrate model in scienti... more The zebrafish, Danio rerio (Hamilton, 1822) has been widely used as a vertebrate model in scientific research and there are many advantages to its use in developmental and physiological studies, such as the transparency of the cho-rion, production of numerous eggs, a sequenced genome and no major rearing difficulties (Lawrence, 2007; Westerfield, 2000). Owing to these assets, the zebrafish has been recently proposed as a model for fish nutrition studies (Hardy, 2007). However, despite its popularity, there are relatively few stud-ies on factors affecting the reproductive performance of the zebrafish, such as diet composition. Indeed, the diet deliv-ered to the broodstock is likely to affect many aspects of fish physiology, making it difficult to compare studies. In addi-tion, husbandry practices have been shown to alter repro-duction in other fish species. For example, food delivered to parental Cyprinus carpio and Oncorhynchus mykiss had an important effect on the quality of the yo...
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2009
... rate of living organisms and the effects on the ecosystems [1], [2] and [3]. A thermodynamic ... more ... rate of living organisms and the effects on the ecosystems [1], [2] and [3]. A thermodynamic equilibrium model of uranium in aqueous systems has been described to interpret the experimental data obtained on the bioavailability of uranium (VI) [4], [5] and [6]. Simon and Garnier ...
Tritium, a radioactive isotope of hydrogen of natural and anthropogenic origin, is ubiquitously p... more Tritium, a radioactive isotope of hydrogen of natural and anthropogenic origin, is ubiquitously present in the environment. Effluents of nuclear center of production are significant anthropogenic sources. With the upcoming project of thermonuclear fusion, tritium releases in the environment may increase. It is therefore important to characterize the ecological risk linked to tritium. The effects of tritiated water (HTO) were therefore studied in zebrafish larvae exposed during 10 days to different dose rates: 1.1x10 2 , 4.1x10 2 and 3.8x10 3 µGy/h for larvae, corresponding respectively to a water contamination of 10 4 , 10 5 and 10 6 Bq/mL of HTO. Those dose rates were higher than 10 μGy/h which is the threshold recommended to start monitoring ecosystems where radiological contaminants are present. Mortality, embryolarval development, immune-, geno and neuro-toxicity, and alterations of tissues were investigated. Results showed that tritiated water exposure induced DNA damage, ROS production and modulated the expression of genes involved in detoxification processes. Moreover, modifications of the muscular tissues (degradation of myofibrils at 4 dpf and disorganization of mitochondria at later stages) were observed. Results differed with HTO dose rates and with developmental stages. These results will drive future research for the development of new HTO-sensitive biomarkers and will allow us to progress in the characterization of the modes of action of tritium in fish.
The objective was to investigate the effects of ionizing radiation induced in zebrafish early lif... more The objective was to investigate the effects of ionizing radiation induced in zebrafish early life stages by coupling responses obtained at the molecular (genotoxicity, ROS production, gene expression) and phenotypic (tissue alteration, embryo-larval development) levels. Here we present results obtained after exposure of 3 hpf larvae to 10 days of gamma irradiation at 3.3 × 101, 1.3 × 102 and 1.2 × 103 µGy/h, close to and higher than the benchmark for protection of ecosystems towards ionizing radiations of 101 µGy/h. Dose rates used in these studies were chosen to be in the 'derived consideration reference level' (DCRL) for gamma irradiation where deleterious effects can appear in freshwater fish. Also, these dose rates were similar to the ones already tested on tritium (beta ionizing radiation) in our previous work, in order to compare both types of ionizing radiation. Results showed that gamma irradiation did not induce any effect on survival and hatching. No effect was observed on DNA damages, but ROS production was increased. Muscle damages were observed for all tested dose rates, similarly to previous results obtained with tritium (beta ionizing radiation) at similar dose rates. Some molecular responses therefore appeared to be relevant for the study of gamma ionizing radiation effects in zebrafish.
This study aimed to determine uranium (U) pollution over time using otoliths as a marker of fish ... more This study aimed to determine uranium (U) pollution over time using otoliths as a marker of fish U contamination. Experiments were performed in field contamination (~20 μg L−1: encaged fish: 15d, 50d and collected wild fish) and in laboratory exposure conditions (20 and 250 μg L−1, 20d). We reported the U seasonal concentrations in field waterborne exposed roach fish (Rutilus rutilus), in organs and otoliths. Otoliths were analyzed by ICPMS and LA-ICP SF MS of the entire growth zone. Concentrations were measured on transects from nucleus to the edge of otoliths to characterize environmental variations of metal accumulation. Results showed a spatial and temporal variation of U contamination in water (from 51 to 9.4 μg L−1 at the surface of the water column), a high and seasonal accumulation in fish organs, mainly the digestive tract (from 1000 to 30,000 ng g−1, fw), the gills (from 1600 to 3200 ng g−1, fw) and the muscle (from 144 to 1054 ng g−1, fw). U was detected throughout the otolith and accumulation varied over the season from 70 to 350 ng g−1, close to the values measured (310 ng g−1) after high exposure levels in laboratory conditions. U in otoliths of encaged fish showed rapid and high U accumulation from 20 to 150 ng g−1. The U accumulation signal was mainly detected on the edge of the otolith, showing two U accumulation peaks, probably correlated to fish age, i.e. 2 years old. Surprisingly, elemental U and Zn signatures followed the same pattern therefore using the same uptake pathways. Laboratory, caging and field experiments indicated that otoliths were able to quickly accumulate U on the surface even for low levels and to store high levels of U. This study is an encouraging first step in using otoliths as a marker of U exposure. Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site.
An overall criterion for protecting freshwaters against uranium chemo-toxicity should encompass a... more An overall criterion for protecting freshwaters against uranium chemo-toxicity should encompass all the compartments of the freshwater environment at risk (water column, sediment, predators, and humans). According to the latest European recommendations, we revised the interim Environmental Quality Standard currently applicable in France, to introduce physico-chemical parameters affecting uranium bioavailability in water and therefore toxicity, by using chemical speciation modelling in aqueous phase including both mineral ligands and organic mat-ter. Additionally, we completed the poor available data set related to sediment toxicity by implementing dedicated standardized tests and we explored the question of secondary poisoning. Human health was also briefly considered, to fulfill the methodological requirements.
h i g h l i g h t s Screening of U distribution among proteins in gill cytosols of U exposed zebr... more h i g h l i g h t s Screening of U distribution among proteins in gill cytosols of U exposed zebrafish. Significant U bioaccumulation in gills after 3 d of realistic chronic exposure. Different U-protein distribution patterns in cytosols as function of exposure level. Higher amount of U in the cytosolic fraction in case of high exposure level. Potential effect of U on Zn cytosolic burden.
Pollutants that occur at sublethal concentrations in the environment may lead to chronic exposure... more Pollutants that occur at sublethal concentrations in the environment may lead to chronic exposure in aquatic organisms. If these pollutants bioaccumulate, then organisms higher in the food chain may also be at risk. Increased attention has thus been focused on the relative importance of dietary uptake, but additional knowledge of the cellular distribution of metals after dietary exposure is required to assess the potential toxicity. The authors address concerns relating to increasing uranium (U) concentrations (from 12 µg/L to 2 mg/L) in the freshwater ecosystem caused by anthropogenic activities. The objective of the present study is to compare uranium bioaccumulation levels in tissues and in the subcellular environment. The authors focused on the cytosol fraction and its microlocalization (TEM-EDX) in the gills and the hepatopancreas (HP) of the crayfish Orconectes limosus after 10 d of direct exposure (at concentrations of 20, 100, and 500 µg/L) and five trophic exposure treatments (at concentrations from 1 to 20 µg/g). Results indicated that adsorption of uranium on the cuticle represents the main contribution of total uranium accumulation to the animal. Accumulation in the gills should be considered only as a marker of waterborne uranium exposure. Accumulation in the HP after trophic environmental exposure conditions was higher (18.9 ± 3.8 µg/g) than after direct exposure. Moreover, no significant difference in the subcellular distribution of uranium (50%) in HP was observed between animals that had been exposed to both types of treatment. A potential toxic effect after uranium accumulation could therefore exist after trophic exposure. This confirms the need to focus further studies on the metal (uranium) risk assessment.
This work aims to investigate the accumulation levels and effects (transcriptional responses, his... more This work aims to investigate the accumulation levels and effects (transcriptional responses, histopathology and survival rate) associated with a wide range of dissolved uranium (U) concentrations (0, 0.03, 0.6, 4 and 8 mg/L of U) on adult male crayfish Procambarus clarkii during 4 (T4) and 10 (T10) days of exposure. The follow-up of the crayfish mortality showed that P. clarkii was highly resistant to U. Increasing waterborne U concentrations led to increasing bioaccumulation in key crayfish organs and increasing histological damages. U distribution in tissues was also evaluated using transmission electron microscopy and showed the presence of a detoxified form of U in the gill's epithelium in the shape of flakes. Expression levels of mitochondrial genes (cox1, atp6 and 12S gene) and genes involved in oxidative stress (sod(Mn) and mt) were examined together with the housekeeping gene 18S. atp6 and mt genes of P. clarkii were cloned and sequenced before analysis. Significant correlations were observed between U bioaccumulation and the down-regulation of both cox1 and sod(Mn) genes. This work provides a first U toxicogenomic and histopathological pattern of P. clarkii, identify U biomarkers and associate gene expression endpoints to accumulation levels. It also provides new insights into the mechanisms involved in U stress.
Tritium (H) is a radioactive isotope of hydrogen. In the environment, the most common form of tri... more Tritium (H) is a radioactive isotope of hydrogen. In the environment, the most common form of tritium is tritiated water (HTO). The present study aimed to identify early biomarkers of HTO contamination through the use of an aquatic model, the zebrafish (Danio rerio). We used the zebrafish embryo-larvae model to investigate the modes of action of HTO exposure at dose rates of 0.4 and 4 mGy/h, dose rates expected to induce deleterious effects on fish. Zebrafish were exposed to HTO from 3 hpf (hours post fertilization) to 96 hpf. The transcriptomic effects were investigated 24 h and 96 h after the beginning of the contamination, using mRNAseq. Results suggested an impact of HTO contamination, regardless of the dose rate, on genes involved in muscle contraction (tnnt2d, tnni2a.4, slc6a1a or atp2a1l) and eye opacity (crygm2d9, crygmxl1, mipb or lim2.3) after 24 h of contamination. Interestingly, an opposite differential expression was highlighted in genes playing a role in muscle contrac...
Aquatic toxicology (Amsterdam, Netherlands), Jan 30, 2017
This study investigated the accumulation pattern and biological effects (genotoxicity and histopa... more This study investigated the accumulation pattern and biological effects (genotoxicity and histopathology) to adult zebrafish (male and female) exposed to a nominal waterborne concentration of 20 μg Lof depleted uranium (DU) for 28 days followed by 27 days of depuration. Accumulation pattern showed that (i) DU accumulated in brain, (ii) levels in digestive tract were higher than those measured in gills and (iii) levels remained high in kidney, brain and ovary despite the 27 days of depuration period. Genotoxicity, assessed by comet assay, was significant not only during DU exposure, but also during depuration phase. Gonads, in particular the testes, were more sensitive than gills. The histology of gonads indicated severe biological damages in males. This study improved knowledge of ecotoxic profile of uranium, for which a large range of biological effects has already been demonstrated.
A non-denaturating isoelectric focusing (ND-IEF) gel electrophoresis protocol has been developed ... more A non-denaturating isoelectric focusing (ND-IEF) gel electrophoresis protocol has been developed to study and identify uranium (U)-protein complexes with laser ablationinductively coupled plasma mass spectrometry (LA-ICP MS) and electrospray ionization mass spectrometry (ESI-MS). The ND-IEF-LA-ICP MS methodology setup was initiated using in vitro U-protein complex standards (i.e., U-bovine serum albumin and U-transferrin) allowing the assessment of U recovery to 64.4±0.4 %. This methodology enabled the quantification of U-protein complexes at 9.03±0.23, 15.27±0.36, and 177.31±25.51 nmol U L −1 in digestive gland cytosols of the crayfish, Procambarus clarkii, exposed respectively to 0, 0.12, and 2.5 μmol of waterborne depleted U L −1 during 10 days. ND-IEF-LA-ICP MS limit of detection was 19.3 pmol U L −1. Elemental ICP MS signals obtained both in ND-IEF electropherograms and in size exclusion chromatograms of in vivo U-protein complexes revealed interactions between U-and Fe-and Cu-proteins. Moreover, three proteins (hemocyanin, pseudohemocyanin-2, and arginine kinase) out of 42 were identified as potential uranium targets in waterborne-exposed crayfish cytosols by microbore reversed phase chromatography coupled to molecular mass spectrometry (µRPC-ESI-MS/MS) after ND-IEF separation.
At present, ecotoxicological information regarding the impact of natural uranium (U) on freshwate... more At present, ecotoxicological information regarding the impact of natural uranium (U) on freshwater ecosystems via the trophic contamination route is scarce. We generated an experimental trophic food chain involving the prey species, Corbicula fluminea, and a predator, Orconectes limosus, for a 10-day and a 30-day feeding periods (food ration: one whole soft body/day/crayfish). We studied the efficiency of U trophic transfer and the distribution of U in the predator. During the test, we varied the quantity of dietary U (from beforehand contaminated bivalves at concentrations ranging from 0.9 ± 0.1 to 20.2 ± 9 g/g fw provided to each crayfish over the 10 days) applying a daily feeding rate equal to 3.9 ± 0.8% fw. The efficiency of U trophic transfer from clams to crayfish varied between 1 and 13% depending on the prey exposure modalities. Accumulation of U was observed in the digestive gland but also in gills, in the muscle, and in the molt of the crayfish after trophic exposure treatments. Under high-level exposure conditions, the digestive gland was the main target-organ, however a significant accumulation was also observed in the stomach. With regard to low levels of trophic exposure, accumulation of U in gills, in the stomach, and in the digestive gland was of the same order of magnitude. Longer exposure period which incorporated a crayfish molt, resulted in a decrease of trophic transfer ratio and a modified U tissue distribution.
Environmental toxicology and chemistry / SETAC, Jan 17, 2015
New data on the nature of the protein targets of U within the zebrafish gills were collected afte... more New data on the nature of the protein targets of U within the zebrafish gills were collected after waterborne exposure to better understand uranium (U) toxicity mechanisms. This study evidenced some common characteristics of the U protein target binding properties such as their role in other essential metals regulation and their phosphorus content. In total 21 potential protein targets, including hemoglobin, were identified and discussed regarding the literature. This article is protected by copyright. All rights reserved.
The zebrafish, Danio rerio (Hamilton, 1822) has been widely used as a vertebrate model in scienti... more The zebrafish, Danio rerio (Hamilton, 1822) has been widely used as a vertebrate model in scientific research and there are many advantages to its use in developmental and physiological studies, such as the transparency of the cho-rion, production of numerous eggs, a sequenced genome and no major rearing difficulties (Lawrence, 2007; Westerfield, 2000). Owing to these assets, the zebrafish has been recently proposed as a model for fish nutrition studies (Hardy, 2007). However, despite its popularity, there are relatively few stud-ies on factors affecting the reproductive performance of the zebrafish, such as diet composition. Indeed, the diet deliv-ered to the broodstock is likely to affect many aspects of fish physiology, making it difficult to compare studies. In addi-tion, husbandry practices have been shown to alter repro-duction in other fish species. For example, food delivered to parental Cyprinus carpio and Oncorhynchus mykiss had an important effect on the quality of the yo...
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2009
... rate of living organisms and the effects on the ecosystems [1], [2] and [3]. A thermodynamic ... more ... rate of living organisms and the effects on the ecosystems [1], [2] and [3]. A thermodynamic equilibrium model of uranium in aqueous systems has been described to interpret the experimental data obtained on the bioavailability of uranium (VI) [4], [5] and [6]. Simon and Garnier ...
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