F. Akcha - Academia.edu (original) (raw)
Papers by F. Akcha
HAL (Le Centre pour la Communication Scientifique Directe), Nov 23, 2010
International audienc
HAL (Le Centre pour la Communication Scientifique Directe), Nov 23, 2010
International audienc
![Research paper thumbnail of Antagonistic Interactions between Benzo[a]pyrene and C<sub>60</sub> in Toxicological Response of Marine Mussels](https://attachments.academia-assets.com/90064713/thumbnails/1.jpg)
](This study aimed to assess the ecotoxicological effects of the interaction of fullerene (C60) and... more This study aimed to assess the ecotoxicological effects of the interaction of fullerene (C60) and benzo[a]pyrene (B[a]P) on the marine mussel, Mytilus galloprovincialis. The uptake of nC60, B[a]P and mixtures of nC60 and B[a]P into tissues was confirmed by GC-MS, LC-HRMS and ICP-MS. Biomarkers of DNA damage as well as proteomics analysis were applied to unravel the toxic effect of B[a]P and C60. Antagonistic responses were observed at the genotoxic and proteomic level. Differentially expressed proteins (DEPs) were only identified in the B[a]P single exposure and the B[a]P mixture exposure groups containing 1 mg/L of C60, the majority of which were down-regulated (~52%). No DEPs were identified at any of the concentrations of nC60 (p < 0.05, 1% FDR). Using DEPs identified at a threshold of (p < 0.05; B[a]P and B[a]P mixture with nC60), gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis indicated that these proteins were enriched with a broad ...
Environmental Science & Technology, 2013
The fate and effects of CuO nanoparticles (CuO NPs) were examined in endobenthic species (Scrobic... more The fate and effects of CuO nanoparticles (CuO NPs) were examined in endobenthic species (Scrobicularia plana, Hediste diversicolor), under environmentally realistic conditions in outdoor mesocosms (exposure to Cu at 10 μg L −1 in particulate (CuO NPs) or soluble salt (CuNO 3) forms) for 21 days. Labile Cu was determined in water and sediment by using diffusive gradient in thin films. No labile Cu being detected from CuO NPs; the observed effects in invertebrates exposed to CuO NPs were mainly attributed to the toxicity of nanoparticulate rather than dissolved Cu toxicity. Bioaccumulation of CuO NPs was observed in both species. Biomarkers were examined at different levels of biological organization: biochemical markers of defense and damage, biomarkers of genotoxicity (comet assay), and behavioral biomarkers (feeding and burrowing). Behavioral biomarkers, antioxidant defenses (catalase, glutathion S-transferase, metallothionein), and genotoxicity are the most sensitive tools to highlight the effect of soluble or nanoparticulate metal forms. Concerning other biomarkers of defense (superoxide dismutase, lactate dehydrogenase, laccase) and damage (thiobarbituric acid reactive substances, acetylcholinesterase, acid phosphatase), no significant effects were detected. This experiment shows the suitability of mesocosms for studying the environmental effects of nanoparticles.
Science of The Total Environment, 2022
Due to new usages and sources, copper (Cu) concentrations are increasing in the Arcachon Basin, a... more Due to new usages and sources, copper (Cu) concentrations are increasing in the Arcachon Basin, an important shellfish production area in France. In the present paper, the trophic transfer of Cu was studied between a microalga, Tetraselmis suecica, and Crassostrea gigas (Pacific oyster) spat. An experimental approach was developed to assess Cu exposure, transfer and toxicity on both phytoplankton and spat. Exposure of microalgal cultures to Cu for 7-8 days (3.1 ± 0.1, 15.7 ± 0.2 and 50.4 ± 1.0 μg Cu·L-1 for the control, Cu15 and Cu50 conditions, respectively) led to concentrations in microalgae (28.3 ± 0.9 and 110.7 ± 11.9 mg Cu·kg dry weight-1 for Cu15 and Cu50, respectively) close to those measured in the field. Despite Cu accumulation, the physiology of the microalgae remained poorly affected. Exposed cultures could only be discriminated from controls by a higher relative content in intracellular reactive oxygen species, and a lower relative content in lipids together with a reduced metabolic activity. By contrast, the fatty acid profile of microalgae was modified, with a particularly relevant lower content of the essential polyunsaturated fatty acid 22:6n-3 (docosahexaenoic acid [DHA]). Following 21 days of spat feeding with Cu15 and Cu50 microalgal cultures, trophic transfer of Cu was observed with a high initial Cu concentration in spat tissues. No effect was observed on oxidative stress endpoints. Cu exposure was responsible for a decrease in the spat condition index, an outcome that could be related to an insufficient DHA supply and extra energy demand as suggested by the overexpression of genes involved in energy metabolism, ATP synthesis and glycogen catabolism.
Marine pollution bulletin, 2021
Telomeres protect the coding sequence of chromosome ends and Telomere Length (TL) has been propos... more Telomeres protect the coding sequence of chromosome ends and Telomere Length (TL) has been proposed as a biomarker of cellular aging, cumulative stress exposure and life-span in humans. With the aim to propose new biomarkers, a q-PCR protocol was adapted for the measurement of TL in the European flounder Platichthys flesus. The protocol was then applied in 2-year-old flounders from the Seine Estuary. The absolute TL in the flounder is 54 ± 13 kbp per genome (mean ± standard error). Considering relative or absolute TL, no correlation was observed with DNA damage and any of the measured contaminant concentrations (trace elements, metabolites of polycyclic aromatic hydrocarbons, polychlorobiphenyls, organochlorinated pesticides, polybrominated diphenyl ethers, perfluoroalkyl substances). Because sampling was limited, further investigations are required to state a possible impact of chemical pollution on flatfish telomeres. This is motivated by correlations observed with organochlorinat...
Bulky DNA adducts and 8-oxo-7,8-dihydro-2´-deoxyguanosine (8-oxodGuo) were measured in gill DNA o... more Bulky DNA adducts and 8-oxo-7,8-dihydro-2´-deoxyguanosine (8-oxodGuo) were measured in gill DNA of benzo[a]pyrene (B[a]P)-exposed mussels (50 mg kg(-1) dw day(-1)), respectively by the (32)P-post-labelling technique and high performance liquid chromatography coupled to electrochemical detection assay. A time-course study was performed for both biomarkers and their potential use for marine biomonitoring discussed for the sentinel species studied. In gills, B[a]P-related DNA adducts were positively correlated with B[a.
Aquatic toxicology (Amsterdam, Netherlands), Jan 9, 2016
The Pacific oyster Crassostrea gigas is the main oyster species produced in the world, and a key ... more The Pacific oyster Crassostrea gigas is the main oyster species produced in the world, and a key coastal economic resource in France. High mortalities affect Pacific oysters since 2008 in France and Europe. Their origins have been attributed to a combination of biotic and abiotic factors, underlining the importance of environment quality. The impact of water pollution has been pointed out and one of the pollutants, the genotoxic herbicide diuron, occurs at high concentrations all along the French coasts. Previous work has revealed that a parental exposure to diuron had a strong impact on hatching rates and offspring development even if spats were not exposed to diuron themselves. In this study, we explored for the first time the transcriptional changes occurring in oyster spats (non exposed) originating from genitors exposed to an environmentally relevant concentration of diuron during gametogenesis using the RNAseq methodology. We identified a transcriptomic remodeling revealing an...
Marine Environmental Research, 2016
Polycyclic aromatic hydrocarbons (PAH) are environmental contaminants that pose significant risk ... more Polycyclic aromatic hydrocarbons (PAH) are environmental contaminants that pose significant risk to health of fish. The International Workshop on Integrated Assessment of Contaminant Impacts on the North Sea (ICON) provided the framework to investigate biomarker responses as well as contaminant concentrations side by side in marine ecosystems. Concentrations of the main PAH metabolites 1hydroxypyrene, 1-hydroxyphenanthren and 3-hydroxybenzo(a)pyrene were determined in bile by HPLC with fluorescence detection. Fish species under investigation were dab (Limanda limanda), flounder (Platichthys flesus) and haddock (Melanogrammus aeglefinus). A contamination gradient was demonstrated from the low contaminated waters of Iceland and offshore regions of the North Sea towards higher concentrations in coastal areas. Concentrations of PAH metabolites differed primarily according to sampling region and secondarily to species. Highlights ► PAH metabolites are useful for monitoring in marine fish species. ► A spatial gradient of increasing PAH contamination could be shown. ► Different fish species could join a pan-European assessment of PAH metabolites. ► Icelandic fish were used for the calculation of background assessment criteria. 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.
Biomarkers in Marine Organisms, 2001
Biomarkers in Marine Organisms, 2001
Biomarkers in Marine Organisms, 2001
Aquatic toxicology (Amsterdam, Netherlands), 2015
In this work, the DNA-damaging effect of hydrogen peroxide on the structural integrity of nucleol... more In this work, the DNA-damaging effect of hydrogen peroxide on the structural integrity of nucleolar organizer regions (NORs) was studied for the first time by comet-FISH in the Pacific oyster Crassostrea gigas. Global DNA damage was assessed in hemocytes using an alkaline version of the comet assay. Next, NOR sensitivity was analyzed by mapping major rDNA repeat unit by fluorescence in situ hybridization (FISH) on the same comet slides. Exposure of hemocytes to 100μM of hydrogen peroxide induced a significant increase in both DNA damage and number of FISH-signals of major ribosomal genes versus the control. Moreover, a significant positive correlation was shown between DNA damage as measured by the comet assay (percentage of DNA in comet tail) and the number of signals present in comet tails. This study demonstrates the potential value of the comet-FISH assay for the study of DNA damage induced by genotoxicant exposure of target genes. It offers a perspective for better understandin...
Mutation research, Jan 18, 2004
In the Eastern English Channel, the potential application of the comet assay and post-labelling t... more In the Eastern English Channel, the potential application of the comet assay and post-labelling technique in dab was evaluated for genotoxicity monitoring of the marine environment. The effects of biotic (age, sex) and abiotic (sampling site and period) factors on the extent of DNA lesions were also studied. Female and male dab of two class of size (juvenile and adult) were collected by trawling in different sites in Seine Bay and Somme Bay during September 2001. Single-strand breaks and adducts were, respectively, measured in erythrocytes and the liver. Results obtained for the adult female were compared with those collected during a first cruise in March 2001 [Akcha et al., Mutat Res. 534 (1-2) (2003) 21]. Significant effects of sex and age were demonstrated on the level of strand breaks. Moreover, a significant interaction between age and sex was shown that might indicate the complex influence of other factors on the extent of DNA damage (i.e. reproduction status). In the adult d...
Comparative biochemistry and physiology. B, Comparative biochemistry, 1993
1. DNA-DNA hybridization showed that mussels (Mytilus edulis) and oysters (Crassostrea gigas) pos... more 1. DNA-DNA hybridization showed that mussels (Mytilus edulis) and oysters (Crassostrea gigas) possess a highly conserved region constituting one or more genes of the ATP-dependent transmembrane transporter family to which belong the mammalian tumor cell genes responsible for multi-drug resistance. 2. Monoclonal antibody C219 visualized two proteins (220 and 240 kDa) which varied quantitatively in mussels depending on the level of organic pollution at the sampling sites. 3. The authors consider whether certain pollutants in the marine environment are capable of inducing pollutant-resistant gene expression.
Mutation Research/Fundamental …, 2004
... These results show the importance of studying the effects of biotic and abiotic factors on th... more ... These results show the importance of studying the effects of biotic and abiotic factors on the ... As oxidative DNA lesions may play a role in mutagenesis and initiation of cancer, DNA strand breaks have been proposed as biomarkers of genotoxicity for aquatic biomonitoring [3 ...
Mutation Research/Genetic Toxicology and Environmental Mutagenesis, 2003
An in situ study of the relationship between marine contamination and genotoxic effects was perfo... more An in situ study of the relationship between marine contamination and genotoxic effects was performed on female dab (Limanda limanda) collected from different sites in the eastern English Channel (France) known to be contaminated by polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs). DNA adducts in liver and DNA strand breaks in blood cells were determined respectively by the nuclease P1-enhanced post-labelling technique and an alkaline version of the comet assay. The extent of DNA base oxidation was also assessed for three of the six sampling sites in the study, using a comet assay in combination with a specific DNA repair enzyme, formamidopyrimidine glycosylase (Fpg). With Comet data, two groups of sites that seem in accordance with the pollution level have been distinguished. The extent of DNA strand breaks was higher in adult than juvenile female dab. From a technical point of view, comet assay sensitivity was affected by high intra-individual variability that accounted for nearly 70% of total variance (the site factor represented no more than 26%). The combined use of the comet assay and Fpg showed the presence of DNA oxidised bases in environmentally exposed dab. Although qualitative differences between the sampling sites were observed in DNA adduct profiles, no significant differences were found for total DNA adduct levels. DNA adducts did not appear to be associated with PAH exposure. Histopathological studies showed hepatic steatosis in most of the animals examined. Only one pre-cancerous lesion (an early stage of hyperplasia) was detected (associated frequency of 0.8%).
Marine Environmental Research, 2010
Polycylic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in the marine environment. The... more Polycylic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in the marine environment. Their toxicity is mainly linked to the ability of marine species to biotransform them into reactive metabolites. PAHs are thus often detected at trace levels in animal tissues. For biomonitoring purposes, this findings have two main consequences, (i) the determination of the PAH tissue concentration is not suitable for the evaluation of individual exposure to PAHs (ii) it can explain sometimes the lack of correlations obtained with relevant markers of toxicity such as genotoxicity biomarkers.
Marine Environmental Research, 2004
DNA single-strand breaks were measured by the comet assay in both gill and hemolymph cells of mus... more DNA single-strand breaks were measured by the comet assay in both gill and hemolymph cells of mussels collected in 3 sampling areas of the French coast (Pointe du Castelli, Pen Bron and Saint-Nazaire Harbour). Whole mussel tissue samples were also collected for the chemical determination of PAH, PCB and heavy metal concentrations. In mussel, a higher level of DNA strand breaks was measured in gill than in hemolymph cells (p < 0:001). Despite a factor of contamination from 2 to 3 between sites, no difference in the extent of mussel DNA strand breaks was shown between sampling locations (p > 0:05), questioning the sensitivity of the assays used in biomonitoring studies.
Marine Environmental Research, 2008
The alkaline comet assay was tested on different microalgae: the dinoflagellates, Karenia mikimot... more The alkaline comet assay was tested on different microalgae: the dinoflagellates, Karenia mikimotoi and Alexandrium minutum, and the diatom, Chaetoceros gracilis. The microalgae were exposed during their exponential growth to the model direct genotoxicant, hydrogen peroxide (1 h, 5 and 100 μM H 2 O 2). Following H 2 O 2 exposure, the comet assay was validated only for K. mikimotoi for which genotoxicity was observed from the lowest tested concentration of 5 μM with a concentrationdependent effect. C. gracilis was too small in size (4 μm) to be correctly analysed. For A. minutum, our lysis buffer was not strong enough to digest the cellulosic thecal plates. For K. mikimotoi, the comet assay was thus applied for the study of the genotoxic effects of different pesticides: epoxiconazole (as Opus formulation), chlorpyriphos-ethyl (as Dursban formulation) and endosulfan at 1, 10 and 100 μg of active substance/L for 24 h. Exposure to epoxiconazole in formulation resulted in an increase in the extent of DNA strand breaks at the highest tested concentration of 100 μg/L. Genotoxicity was also observed for chlorpyriphos-ethyl in formulation from 1 μg/L (p < 0.05), with a significant increase at 10 μg/L. Endosulfan exposure resulted in DNA damage for K. mikimotoi nuclei. Genotoxicity was observed from 1 μg/L of endosulfan and was not concentration dependent.
HAL (Le Centre pour la Communication Scientifique Directe), Nov 23, 2010
International audienc
HAL (Le Centre pour la Communication Scientifique Directe), Nov 23, 2010
International audienc
This study aimed to assess the ecotoxicological effects of the interaction of fullerene (C60) and... more This study aimed to assess the ecotoxicological effects of the interaction of fullerene (C60) and benzo[a]pyrene (B[a]P) on the marine mussel, Mytilus galloprovincialis. The uptake of nC60, B[a]P and mixtures of nC60 and B[a]P into tissues was confirmed by GC-MS, LC-HRMS and ICP-MS. Biomarkers of DNA damage as well as proteomics analysis were applied to unravel the toxic effect of B[a]P and C60. Antagonistic responses were observed at the genotoxic and proteomic level. Differentially expressed proteins (DEPs) were only identified in the B[a]P single exposure and the B[a]P mixture exposure groups containing 1 mg/L of C60, the majority of which were down-regulated (~52%). No DEPs were identified at any of the concentrations of nC60 (p < 0.05, 1% FDR). Using DEPs identified at a threshold of (p < 0.05; B[a]P and B[a]P mixture with nC60), gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis indicated that these proteins were enriched with a broad ...
Environmental Science & Technology, 2013
The fate and effects of CuO nanoparticles (CuO NPs) were examined in endobenthic species (Scrobic... more The fate and effects of CuO nanoparticles (CuO NPs) were examined in endobenthic species (Scrobicularia plana, Hediste diversicolor), under environmentally realistic conditions in outdoor mesocosms (exposure to Cu at 10 μg L −1 in particulate (CuO NPs) or soluble salt (CuNO 3) forms) for 21 days. Labile Cu was determined in water and sediment by using diffusive gradient in thin films. No labile Cu being detected from CuO NPs; the observed effects in invertebrates exposed to CuO NPs were mainly attributed to the toxicity of nanoparticulate rather than dissolved Cu toxicity. Bioaccumulation of CuO NPs was observed in both species. Biomarkers were examined at different levels of biological organization: biochemical markers of defense and damage, biomarkers of genotoxicity (comet assay), and behavioral biomarkers (feeding and burrowing). Behavioral biomarkers, antioxidant defenses (catalase, glutathion S-transferase, metallothionein), and genotoxicity are the most sensitive tools to highlight the effect of soluble or nanoparticulate metal forms. Concerning other biomarkers of defense (superoxide dismutase, lactate dehydrogenase, laccase) and damage (thiobarbituric acid reactive substances, acetylcholinesterase, acid phosphatase), no significant effects were detected. This experiment shows the suitability of mesocosms for studying the environmental effects of nanoparticles.
Science of The Total Environment, 2022
Due to new usages and sources, copper (Cu) concentrations are increasing in the Arcachon Basin, a... more Due to new usages and sources, copper (Cu) concentrations are increasing in the Arcachon Basin, an important shellfish production area in France. In the present paper, the trophic transfer of Cu was studied between a microalga, Tetraselmis suecica, and Crassostrea gigas (Pacific oyster) spat. An experimental approach was developed to assess Cu exposure, transfer and toxicity on both phytoplankton and spat. Exposure of microalgal cultures to Cu for 7-8 days (3.1 ± 0.1, 15.7 ± 0.2 and 50.4 ± 1.0 μg Cu·L-1 for the control, Cu15 and Cu50 conditions, respectively) led to concentrations in microalgae (28.3 ± 0.9 and 110.7 ± 11.9 mg Cu·kg dry weight-1 for Cu15 and Cu50, respectively) close to those measured in the field. Despite Cu accumulation, the physiology of the microalgae remained poorly affected. Exposed cultures could only be discriminated from controls by a higher relative content in intracellular reactive oxygen species, and a lower relative content in lipids together with a reduced metabolic activity. By contrast, the fatty acid profile of microalgae was modified, with a particularly relevant lower content of the essential polyunsaturated fatty acid 22:6n-3 (docosahexaenoic acid [DHA]). Following 21 days of spat feeding with Cu15 and Cu50 microalgal cultures, trophic transfer of Cu was observed with a high initial Cu concentration in spat tissues. No effect was observed on oxidative stress endpoints. Cu exposure was responsible for a decrease in the spat condition index, an outcome that could be related to an insufficient DHA supply and extra energy demand as suggested by the overexpression of genes involved in energy metabolism, ATP synthesis and glycogen catabolism.
Marine pollution bulletin, 2021
Telomeres protect the coding sequence of chromosome ends and Telomere Length (TL) has been propos... more Telomeres protect the coding sequence of chromosome ends and Telomere Length (TL) has been proposed as a biomarker of cellular aging, cumulative stress exposure and life-span in humans. With the aim to propose new biomarkers, a q-PCR protocol was adapted for the measurement of TL in the European flounder Platichthys flesus. The protocol was then applied in 2-year-old flounders from the Seine Estuary. The absolute TL in the flounder is 54 ± 13 kbp per genome (mean ± standard error). Considering relative or absolute TL, no correlation was observed with DNA damage and any of the measured contaminant concentrations (trace elements, metabolites of polycyclic aromatic hydrocarbons, polychlorobiphenyls, organochlorinated pesticides, polybrominated diphenyl ethers, perfluoroalkyl substances). Because sampling was limited, further investigations are required to state a possible impact of chemical pollution on flatfish telomeres. This is motivated by correlations observed with organochlorinat...
Bulky DNA adducts and 8-oxo-7,8-dihydro-2´-deoxyguanosine (8-oxodGuo) were measured in gill DNA o... more Bulky DNA adducts and 8-oxo-7,8-dihydro-2´-deoxyguanosine (8-oxodGuo) were measured in gill DNA of benzo[a]pyrene (B[a]P)-exposed mussels (50 mg kg(-1) dw day(-1)), respectively by the (32)P-post-labelling technique and high performance liquid chromatography coupled to electrochemical detection assay. A time-course study was performed for both biomarkers and their potential use for marine biomonitoring discussed for the sentinel species studied. In gills, B[a]P-related DNA adducts were positively correlated with B[a.
Aquatic toxicology (Amsterdam, Netherlands), Jan 9, 2016
The Pacific oyster Crassostrea gigas is the main oyster species produced in the world, and a key ... more The Pacific oyster Crassostrea gigas is the main oyster species produced in the world, and a key coastal economic resource in France. High mortalities affect Pacific oysters since 2008 in France and Europe. Their origins have been attributed to a combination of biotic and abiotic factors, underlining the importance of environment quality. The impact of water pollution has been pointed out and one of the pollutants, the genotoxic herbicide diuron, occurs at high concentrations all along the French coasts. Previous work has revealed that a parental exposure to diuron had a strong impact on hatching rates and offspring development even if spats were not exposed to diuron themselves. In this study, we explored for the first time the transcriptional changes occurring in oyster spats (non exposed) originating from genitors exposed to an environmentally relevant concentration of diuron during gametogenesis using the RNAseq methodology. We identified a transcriptomic remodeling revealing an...
Marine Environmental Research, 2016
Polycyclic aromatic hydrocarbons (PAH) are environmental contaminants that pose significant risk ... more Polycyclic aromatic hydrocarbons (PAH) are environmental contaminants that pose significant risk to health of fish. The International Workshop on Integrated Assessment of Contaminant Impacts on the North Sea (ICON) provided the framework to investigate biomarker responses as well as contaminant concentrations side by side in marine ecosystems. Concentrations of the main PAH metabolites 1hydroxypyrene, 1-hydroxyphenanthren and 3-hydroxybenzo(a)pyrene were determined in bile by HPLC with fluorescence detection. Fish species under investigation were dab (Limanda limanda), flounder (Platichthys flesus) and haddock (Melanogrammus aeglefinus). A contamination gradient was demonstrated from the low contaminated waters of Iceland and offshore regions of the North Sea towards higher concentrations in coastal areas. Concentrations of PAH metabolites differed primarily according to sampling region and secondarily to species. Highlights ► PAH metabolites are useful for monitoring in marine fish species. ► A spatial gradient of increasing PAH contamination could be shown. ► Different fish species could join a pan-European assessment of PAH metabolites. ► Icelandic fish were used for the calculation of background assessment criteria. 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.
Biomarkers in Marine Organisms, 2001
Biomarkers in Marine Organisms, 2001
Biomarkers in Marine Organisms, 2001
Aquatic toxicology (Amsterdam, Netherlands), 2015
In this work, the DNA-damaging effect of hydrogen peroxide on the structural integrity of nucleol... more In this work, the DNA-damaging effect of hydrogen peroxide on the structural integrity of nucleolar organizer regions (NORs) was studied for the first time by comet-FISH in the Pacific oyster Crassostrea gigas. Global DNA damage was assessed in hemocytes using an alkaline version of the comet assay. Next, NOR sensitivity was analyzed by mapping major rDNA repeat unit by fluorescence in situ hybridization (FISH) on the same comet slides. Exposure of hemocytes to 100μM of hydrogen peroxide induced a significant increase in both DNA damage and number of FISH-signals of major ribosomal genes versus the control. Moreover, a significant positive correlation was shown between DNA damage as measured by the comet assay (percentage of DNA in comet tail) and the number of signals present in comet tails. This study demonstrates the potential value of the comet-FISH assay for the study of DNA damage induced by genotoxicant exposure of target genes. It offers a perspective for better understandin...
Mutation research, Jan 18, 2004
In the Eastern English Channel, the potential application of the comet assay and post-labelling t... more In the Eastern English Channel, the potential application of the comet assay and post-labelling technique in dab was evaluated for genotoxicity monitoring of the marine environment. The effects of biotic (age, sex) and abiotic (sampling site and period) factors on the extent of DNA lesions were also studied. Female and male dab of two class of size (juvenile and adult) were collected by trawling in different sites in Seine Bay and Somme Bay during September 2001. Single-strand breaks and adducts were, respectively, measured in erythrocytes and the liver. Results obtained for the adult female were compared with those collected during a first cruise in March 2001 [Akcha et al., Mutat Res. 534 (1-2) (2003) 21]. Significant effects of sex and age were demonstrated on the level of strand breaks. Moreover, a significant interaction between age and sex was shown that might indicate the complex influence of other factors on the extent of DNA damage (i.e. reproduction status). In the adult d...
Comparative biochemistry and physiology. B, Comparative biochemistry, 1993
1. DNA-DNA hybridization showed that mussels (Mytilus edulis) and oysters (Crassostrea gigas) pos... more 1. DNA-DNA hybridization showed that mussels (Mytilus edulis) and oysters (Crassostrea gigas) possess a highly conserved region constituting one or more genes of the ATP-dependent transmembrane transporter family to which belong the mammalian tumor cell genes responsible for multi-drug resistance. 2. Monoclonal antibody C219 visualized two proteins (220 and 240 kDa) which varied quantitatively in mussels depending on the level of organic pollution at the sampling sites. 3. The authors consider whether certain pollutants in the marine environment are capable of inducing pollutant-resistant gene expression.
Mutation Research/Fundamental …, 2004
... These results show the importance of studying the effects of biotic and abiotic factors on th... more ... These results show the importance of studying the effects of biotic and abiotic factors on the ... As oxidative DNA lesions may play a role in mutagenesis and initiation of cancer, DNA strand breaks have been proposed as biomarkers of genotoxicity for aquatic biomonitoring [3 ...
Mutation Research/Genetic Toxicology and Environmental Mutagenesis, 2003
An in situ study of the relationship between marine contamination and genotoxic effects was perfo... more An in situ study of the relationship between marine contamination and genotoxic effects was performed on female dab (Limanda limanda) collected from different sites in the eastern English Channel (France) known to be contaminated by polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs). DNA adducts in liver and DNA strand breaks in blood cells were determined respectively by the nuclease P1-enhanced post-labelling technique and an alkaline version of the comet assay. The extent of DNA base oxidation was also assessed for three of the six sampling sites in the study, using a comet assay in combination with a specific DNA repair enzyme, formamidopyrimidine glycosylase (Fpg). With Comet data, two groups of sites that seem in accordance with the pollution level have been distinguished. The extent of DNA strand breaks was higher in adult than juvenile female dab. From a technical point of view, comet assay sensitivity was affected by high intra-individual variability that accounted for nearly 70% of total variance (the site factor represented no more than 26%). The combined use of the comet assay and Fpg showed the presence of DNA oxidised bases in environmentally exposed dab. Although qualitative differences between the sampling sites were observed in DNA adduct profiles, no significant differences were found for total DNA adduct levels. DNA adducts did not appear to be associated with PAH exposure. Histopathological studies showed hepatic steatosis in most of the animals examined. Only one pre-cancerous lesion (an early stage of hyperplasia) was detected (associated frequency of 0.8%).
Marine Environmental Research, 2010
Polycylic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in the marine environment. The... more Polycylic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in the marine environment. Their toxicity is mainly linked to the ability of marine species to biotransform them into reactive metabolites. PAHs are thus often detected at trace levels in animal tissues. For biomonitoring purposes, this findings have two main consequences, (i) the determination of the PAH tissue concentration is not suitable for the evaluation of individual exposure to PAHs (ii) it can explain sometimes the lack of correlations obtained with relevant markers of toxicity such as genotoxicity biomarkers.
Marine Environmental Research, 2004
DNA single-strand breaks were measured by the comet assay in both gill and hemolymph cells of mus... more DNA single-strand breaks were measured by the comet assay in both gill and hemolymph cells of mussels collected in 3 sampling areas of the French coast (Pointe du Castelli, Pen Bron and Saint-Nazaire Harbour). Whole mussel tissue samples were also collected for the chemical determination of PAH, PCB and heavy metal concentrations. In mussel, a higher level of DNA strand breaks was measured in gill than in hemolymph cells (p < 0:001). Despite a factor of contamination from 2 to 3 between sites, no difference in the extent of mussel DNA strand breaks was shown between sampling locations (p > 0:05), questioning the sensitivity of the assays used in biomonitoring studies.
Marine Environmental Research, 2008
The alkaline comet assay was tested on different microalgae: the dinoflagellates, Karenia mikimot... more The alkaline comet assay was tested on different microalgae: the dinoflagellates, Karenia mikimotoi and Alexandrium minutum, and the diatom, Chaetoceros gracilis. The microalgae were exposed during their exponential growth to the model direct genotoxicant, hydrogen peroxide (1 h, 5 and 100 μM H 2 O 2). Following H 2 O 2 exposure, the comet assay was validated only for K. mikimotoi for which genotoxicity was observed from the lowest tested concentration of 5 μM with a concentrationdependent effect. C. gracilis was too small in size (4 μm) to be correctly analysed. For A. minutum, our lysis buffer was not strong enough to digest the cellulosic thecal plates. For K. mikimotoi, the comet assay was thus applied for the study of the genotoxic effects of different pesticides: epoxiconazole (as Opus formulation), chlorpyriphos-ethyl (as Dursban formulation) and endosulfan at 1, 10 and 100 μg of active substance/L for 24 h. Exposure to epoxiconazole in formulation resulted in an increase in the extent of DNA strand breaks at the highest tested concentration of 100 μg/L. Genotoxicity was also observed for chlorpyriphos-ethyl in formulation from 1 μg/L (p < 0.05), with a significant increase at 10 μg/L. Endosulfan exposure resulted in DNA damage for K. mikimotoi nuclei. Genotoxicity was observed from 1 μg/L of endosulfan and was not concentration dependent.