Perfluoroethylcyclohexane sulfonate (PFECHS), mainly used in hydraulic fluids in aircrafts, is a ... more Perfluoroethylcyclohexane sulfonate (PFECHS), mainly used in hydraulic fluids in aircrafts, is a member of the perfluoroalkyl sulfonate family which includes the regulated perfluorooctane sulfonate (PFOS). PFECHS has been reported in environmental samples but its toxicity to aquatic organisms is unknown. The objectives of this study were to identify biological pathways altered by sublethal exposure (12 d) of D. magna to PFECHS (0.06, 0.6, and 6 mg/L) using microarray and quantitative real-time PCR and to identify potential biomarkers to link transcriptomic to phenotypic responses. PFECHS was also quantified in surface water samples (1.04e1.38 ng/L) collected from the St. Lawrence River, Canada. Transcriptomic analyses indicated the under-regulation of vitellogenin-related genes (VTG1) in PFECHS-exposed groups. PFECHS exposure also led to the up-regulation of genes related to cuticle. VTG was selected as a potential cellular marker and identified in D. magna using an immuno-specific assay and quantified using Western blot and LC/MS/MS. Results indicated a decrease of VTG content in exposed D. magna which was in concordance with the transcription of VTG-related genes. No effects were observed on survival, molting, or reproduction at the individual/population levels. Overall, results suggest endocrine disruption potential for PFECHS in D. magna at concentrations higher than levels reported in the aquatic environment. Crown
Multi-biological level assessments have become
great tools to evaluate the health of aquatic ecos... more Multi-biological level assessments have become great tools to evaluate the health of aquatic ecosystems. Using this approach, a complementary study was designed to evaluate the health of yellow perch (Perca flavescens) populations in the St. Lawrence River (Quebec, Canada). In the present study, stress responses were compared at the transcriptomic, cellular, and tissue levels in yellow perch collected at six sites along the river: Lake St. François, Lake St. Louis (north and south), Beauregard Island and Lake St. Pierre (north and south). These results complement the physiological and chemical parameters as well as pathogen infection investigated in a companion paper published in the present issue. Thiobarbituric acid reactive substance (TBARS) analyses indicated the presence of oxidative stress in fish collected in the southern part of Lake St. Louis and at the downstream sites of Lake St. Pierre. High lipid peroxidation levels were found in the muscle of yellow perch caught at Beauregard Island, located downstream of the Montreal’s wastewater treatment plant, suggesting an impact of the municipal effluent on redox homeostasis. Transcriptomic results indicated the downregulation of genes related to lipid, glucose, and retinoid in southern Lake St. Pierre as well as a decrease in retinoid storage. Overall, biochemical and molecular markers indicated that the health status of yellow perch followed a decreasing gradient from upstream to downstream of the St. Lawrence River. This gradient is representative of the cumulative negative impacts of human activities on water and habitat quality along the river.
A multi-disciplinary approach was used to evaluate
the health of yellow perch (Perca flavescens) ... more A multi-disciplinary approach was used to evaluate the health of yellow perch (Perca flavescens) in the St. Lawrence River (Quebec, Canada), which is experiencing a severe population decline in the downstream portion of the river. Physiological parameters, liver alterations, trace metal concentrations, parasite prevalence and abundance, stable isotope composition, and the presence/absence of the viral hemorragic septicemia virus (VHSV) were evaluated in perch collected at six sites along the river: Lake St. François, Lake St. Louis (north and south), Beauregard Island, and Lake St. Pierre (north and south). Trace metal concentrations in surface water were higher in Lake St. Louis and downstream of a major urban wastewater treatment plant discharge, indicating that this effluent was a significant source of Cu, As, Ag, Zn, and Cd. Levels of Pb in surface water exceeded thresholds for the protection of aquatic life in Lake St. Louis and were negatively correlated with body condition index in this lake. In Lake St. Pierre, Cu, Ag, and Cd bioaccumulated significantly in perch liver and lower body condition index and greater liver damage were observed compared to upstream sites. Parasite analyses indicated a higher abundance of metacercariae of the trematodes Apophallus brevis and Diplostomum spp. in Lake St. Louis, and VHSV was not detected in the liver of yellow perch for all studied sites. Overall, results suggested that the global health of yellow perch from Lake St. Pierre is lower compared to upstream studied sites, which could contribute to the documented population collapse at this site.
Tris (2-butoxyethyl) phosphate (TBOEP) is an organophosphorous-containing flame retardant (OPFR) ... more Tris (2-butoxyethyl) phosphate (TBOEP) is an organophosphorous-containing flame retardant (OPFR) of high production volume used in a broad range of applications. The use of TBOEP containing products has resulted in its release and ubiquitous occurrence in the aquatic environment. In this study, Daphnia magna transcriptomic response was measured by microarray to evaluate sublethal effects of TBOEP as part of a multi-level biological approach including specific gene transcription measured by qRT-PCR, enzyme activity, and life-history endpoints (i.e., survival, growth and reproduction). Chronic exposure (21 d) to a range of sublethal concentrations of TBOEP (14.7–1470 lg L1) did not impact growth, survival or reproduction, although the number of offspring decreased between the lowest and the highest dose. Gene transcription profiling by microarray analysis revealed that 101 genes were differentially transcribed in response to TBOEP (fold change treated/control ±1, p < 0.05). Most of the responding genes were involved in protein metabolism (9), biosynthesis (4) and energy metabolism (6) indicating that TBOEP could have chronic toxic effects on aquatic organisms at sublethal doses by disrupting essential biological pathways. Nine genes were found to be commonly affected by more than one dose, including a gene coding for cathepsin D and multiple isoforms of genes coding for hemoglobin, suggesting potential biomarkers of interest. Microarray results were confirmed by qRT-PCR and measurements at the protein level as cathepsin D enzymatic activity increased significantly in the highest dose treatment. Results highlight the relevance of using the transcriptomic response of D. magna as a first line of evidence to unravel the mode of action of chemicals.
Spodoptera frugiperda is a polyphagous lepidopteran pest that encounters a wide range of toxic pl... more Spodoptera frugiperda is a polyphagous lepidopteran pest that encounters a wide range of toxic plant metabolites in its diet. The ability of this insect to adapt to its chemical environment might be explained by the action of major detoxification enzymes such as cytochrome P450s (or CYP). Forty-two sequences coding for P450s were identified and most of the transcripts were found to be expressed in the midgut, Malpighian tubules and fat body of S. frugiperda larvae. Relatively few P450s were expressed in the established cell line Sf9. In order to gain information on how these genes respond to different chemical compounds, larvae and Sf9 cells were exposed to plant secondary metabolites (indole, indole-3-carbinol, quercetin, 2-tridecanone and xanthotoxin), insecticides (deltamethrin, fipronil, methoprene, methoxyfenozide) or model inducers (clofibrate and phenobarbital). Several genes were induced by plant chemicals such as P450s from the 6B, 321A and 9A subfamilies. Only a few genes responded to insecticides, belonging principally to the CYP9A family. There was little overlap between the response in vivo measured in the midgut and the response in vitro in Sf9 cells. In addition, regulatory elements were detected in the promoter region of these genes. In conclusion, several P450s were identified that could potentially be involved in the adaptation of S. frugiperda to its chemical environment.
Perfluoroethylcyclohexane sulfonate (PFECHS), mainly used in hydraulic fluids in aircrafts, is a ... more Perfluoroethylcyclohexane sulfonate (PFECHS), mainly used in hydraulic fluids in aircrafts, is a member of the perfluoroalkyl sulfonate family which includes the regulated perfluorooctane sulfonate (PFOS). PFECHS has been reported in environmental samples but its toxicity to aquatic organisms is unknown. The objectives of this study were to identify biological pathways altered by sublethal exposure (12 d) of D. magna to PFECHS (0.06, 0.6, and 6 mg/L) using microarray and quantitative real-time PCR and to identify potential biomarkers to link transcriptomic to phenotypic responses. PFECHS was also quantified in surface water samples (1.04e1.38 ng/L) collected from the St. Lawrence River, Canada. Transcriptomic analyses indicated the under-regulation of vitellogenin-related genes (VTG1) in PFECHS-exposed groups. PFECHS exposure also led to the up-regulation of genes related to cuticle. VTG was selected as a potential cellular marker and identified in D. magna using an immuno-specific assay and quantified using Western blot and LC/MS/MS. Results indicated a decrease of VTG content in exposed D. magna which was in concordance with the transcription of VTG-related genes. No effects were observed on survival, molting, or reproduction at the individual/population levels. Overall, results suggest endocrine disruption potential for PFECHS in D. magna at concentrations higher than levels reported in the aquatic environment. Crown
Multi-biological level assessments have become
great tools to evaluate the health of aquatic ecos... more Multi-biological level assessments have become great tools to evaluate the health of aquatic ecosystems. Using this approach, a complementary study was designed to evaluate the health of yellow perch (Perca flavescens) populations in the St. Lawrence River (Quebec, Canada). In the present study, stress responses were compared at the transcriptomic, cellular, and tissue levels in yellow perch collected at six sites along the river: Lake St. François, Lake St. Louis (north and south), Beauregard Island and Lake St. Pierre (north and south). These results complement the physiological and chemical parameters as well as pathogen infection investigated in a companion paper published in the present issue. Thiobarbituric acid reactive substance (TBARS) analyses indicated the presence of oxidative stress in fish collected in the southern part of Lake St. Louis and at the downstream sites of Lake St. Pierre. High lipid peroxidation levels were found in the muscle of yellow perch caught at Beauregard Island, located downstream of the Montreal’s wastewater treatment plant, suggesting an impact of the municipal effluent on redox homeostasis. Transcriptomic results indicated the downregulation of genes related to lipid, glucose, and retinoid in southern Lake St. Pierre as well as a decrease in retinoid storage. Overall, biochemical and molecular markers indicated that the health status of yellow perch followed a decreasing gradient from upstream to downstream of the St. Lawrence River. This gradient is representative of the cumulative negative impacts of human activities on water and habitat quality along the river.
A multi-disciplinary approach was used to evaluate
the health of yellow perch (Perca flavescens) ... more A multi-disciplinary approach was used to evaluate the health of yellow perch (Perca flavescens) in the St. Lawrence River (Quebec, Canada), which is experiencing a severe population decline in the downstream portion of the river. Physiological parameters, liver alterations, trace metal concentrations, parasite prevalence and abundance, stable isotope composition, and the presence/absence of the viral hemorragic septicemia virus (VHSV) were evaluated in perch collected at six sites along the river: Lake St. François, Lake St. Louis (north and south), Beauregard Island, and Lake St. Pierre (north and south). Trace metal concentrations in surface water were higher in Lake St. Louis and downstream of a major urban wastewater treatment plant discharge, indicating that this effluent was a significant source of Cu, As, Ag, Zn, and Cd. Levels of Pb in surface water exceeded thresholds for the protection of aquatic life in Lake St. Louis and were negatively correlated with body condition index in this lake. In Lake St. Pierre, Cu, Ag, and Cd bioaccumulated significantly in perch liver and lower body condition index and greater liver damage were observed compared to upstream sites. Parasite analyses indicated a higher abundance of metacercariae of the trematodes Apophallus brevis and Diplostomum spp. in Lake St. Louis, and VHSV was not detected in the liver of yellow perch for all studied sites. Overall, results suggested that the global health of yellow perch from Lake St. Pierre is lower compared to upstream studied sites, which could contribute to the documented population collapse at this site.
Tris (2-butoxyethyl) phosphate (TBOEP) is an organophosphorous-containing flame retardant (OPFR) ... more Tris (2-butoxyethyl) phosphate (TBOEP) is an organophosphorous-containing flame retardant (OPFR) of high production volume used in a broad range of applications. The use of TBOEP containing products has resulted in its release and ubiquitous occurrence in the aquatic environment. In this study, Daphnia magna transcriptomic response was measured by microarray to evaluate sublethal effects of TBOEP as part of a multi-level biological approach including specific gene transcription measured by qRT-PCR, enzyme activity, and life-history endpoints (i.e., survival, growth and reproduction). Chronic exposure (21 d) to a range of sublethal concentrations of TBOEP (14.7–1470 lg L1) did not impact growth, survival or reproduction, although the number of offspring decreased between the lowest and the highest dose. Gene transcription profiling by microarray analysis revealed that 101 genes were differentially transcribed in response to TBOEP (fold change treated/control ±1, p < 0.05). Most of the responding genes were involved in protein metabolism (9), biosynthesis (4) and energy metabolism (6) indicating that TBOEP could have chronic toxic effects on aquatic organisms at sublethal doses by disrupting essential biological pathways. Nine genes were found to be commonly affected by more than one dose, including a gene coding for cathepsin D and multiple isoforms of genes coding for hemoglobin, suggesting potential biomarkers of interest. Microarray results were confirmed by qRT-PCR and measurements at the protein level as cathepsin D enzymatic activity increased significantly in the highest dose treatment. Results highlight the relevance of using the transcriptomic response of D. magna as a first line of evidence to unravel the mode of action of chemicals.
Spodoptera frugiperda is a polyphagous lepidopteran pest that encounters a wide range of toxic pl... more Spodoptera frugiperda is a polyphagous lepidopteran pest that encounters a wide range of toxic plant metabolites in its diet. The ability of this insect to adapt to its chemical environment might be explained by the action of major detoxification enzymes such as cytochrome P450s (or CYP). Forty-two sequences coding for P450s were identified and most of the transcripts were found to be expressed in the midgut, Malpighian tubules and fat body of S. frugiperda larvae. Relatively few P450s were expressed in the established cell line Sf9. In order to gain information on how these genes respond to different chemical compounds, larvae and Sf9 cells were exposed to plant secondary metabolites (indole, indole-3-carbinol, quercetin, 2-tridecanone and xanthotoxin), insecticides (deltamethrin, fipronil, methoprene, methoxyfenozide) or model inducers (clofibrate and phenobarbital). Several genes were induced by plant chemicals such as P450s from the 6B, 321A and 9A subfamilies. Only a few genes responded to insecticides, belonging principally to the CYP9A family. There was little overlap between the response in vivo measured in the midgut and the response in vitro in Sf9 cells. In addition, regulatory elements were detected in the promoter region of these genes. In conclusion, several P450s were identified that could potentially be involved in the adaptation of S. frugiperda to its chemical environment.
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Papers by Maeva Giraudo
great tools to evaluate the health of aquatic ecosystems.
Using this approach, a complementary study was designed
to evaluate the health of yellow perch (Perca flavescens) populations
in the St. Lawrence River (Quebec, Canada). In the
present study, stress responses were compared at the
transcriptomic, cellular, and tissue levels in yellow perch collected
at six sites along the river: Lake St. François, Lake St.
Louis (north and south), Beauregard Island and Lake St. Pierre
(north and south). These results complement the physiological
and chemical parameters as well as pathogen infection investigated
in a companion paper published in the present issue.
Thiobarbituric acid reactive substance (TBARS) analyses indicated
the presence of oxidative stress in fish collected in the
southern part of Lake St. Louis and at the downstream sites of
Lake St. Pierre. High lipid peroxidation levels were found in
the muscle of yellow perch caught at Beauregard Island,
located downstream of the Montreal’s wastewater treatment
plant, suggesting an impact of the municipal effluent on redox
homeostasis. Transcriptomic results indicated the downregulation
of genes related to lipid, glucose, and retinoid in
southern Lake St. Pierre as well as a decrease in retinoid storage.
Overall, biochemical and molecular markers indicated
that the health status of yellow perch followed a decreasing
gradient from upstream to downstream of the St. Lawrence
River. This gradient is representative of the cumulative negative
impacts of human activities on water and habitat quality
along the river.
the health of yellow perch (Perca flavescens) in the St.
Lawrence River (Quebec, Canada), which is experiencing a
severe population decline in the downstream portion of the
river. Physiological parameters, liver alterations, trace metal
concentrations, parasite prevalence and abundance, stable isotope
composition, and the presence/absence of the viral
hemorragic septicemia virus (VHSV) were evaluated in perch
collected at six sites along the river: Lake St. François, Lake
St. Louis (north and south), Beauregard Island, and Lake St.
Pierre (north and south). Trace metal concentrations in surface
water were higher in Lake St. Louis and downstream of a
major urban wastewater treatment plant discharge, indicating
that this effluent was a significant source of Cu, As, Ag, Zn,
and Cd. Levels of Pb in surface water exceeded thresholds for
the protection of aquatic life in Lake St. Louis and were negatively
correlated with body condition index in this lake. In
Lake St. Pierre, Cu, Ag, and Cd bioaccumulated significantly
in perch liver and lower body condition index and greater liver
damage were observed compared to upstream sites. Parasite
analyses indicated a higher abundance of metacercariae of the
trematodes Apophallus brevis and Diplostomum spp. in Lake
St. Louis, and VHSV was not detected in the liver of yellow
perch for all studied sites. Overall, results suggested that the
global health of yellow perch from Lake St. Pierre is lower
compared to upstream studied sites, which could contribute to
the documented population collapse at this site.
high production volume used in a broad range of applications. The use of TBOEP containing products has resulted in its release and ubiquitous occurrence in the aquatic environment. In this study, Daphnia magna transcriptomic response was measured by microarray to evaluate sublethal effects of TBOEP as part of a multi-level biological approach including specific gene transcription measured by qRT-PCR, enzyme activity, and life-history endpoints (i.e., survival, growth and reproduction). Chronic exposure (21 d) to a range of sublethal concentrations of TBOEP (14.7–1470 lg L1) did not impact growth, survival or reproduction, although the number of offspring decreased between the lowest and the highest dose. Gene transcription profiling by microarray analysis revealed that 101 genes were differentially transcribed in response to TBOEP (fold change treated/control ±1, p < 0.05). Most of the responding genes were involved in protein metabolism (9), biosynthesis (4) and energy metabolism (6) indicating that TBOEP could have chronic toxic effects on aquatic organisms at sublethal doses by disrupting essential biological pathways. Nine genes were found to be commonly affected by more than one dose, including a gene coding for cathepsin D and multiple isoforms of genes coding for hemoglobin, suggesting potential biomarkers of interest. Microarray results were confirmed by qRT-PCR and measurements at the protein level as cathepsin D enzymatic activity increased significantly in the highest dose treatment. Results highlight the relevance of using the transcriptomic response of D. magna as a first line of evidence to unravel the mode of action of chemicals.
great tools to evaluate the health of aquatic ecosystems.
Using this approach, a complementary study was designed
to evaluate the health of yellow perch (Perca flavescens) populations
in the St. Lawrence River (Quebec, Canada). In the
present study, stress responses were compared at the
transcriptomic, cellular, and tissue levels in yellow perch collected
at six sites along the river: Lake St. François, Lake St.
Louis (north and south), Beauregard Island and Lake St. Pierre
(north and south). These results complement the physiological
and chemical parameters as well as pathogen infection investigated
in a companion paper published in the present issue.
Thiobarbituric acid reactive substance (TBARS) analyses indicated
the presence of oxidative stress in fish collected in the
southern part of Lake St. Louis and at the downstream sites of
Lake St. Pierre. High lipid peroxidation levels were found in
the muscle of yellow perch caught at Beauregard Island,
located downstream of the Montreal’s wastewater treatment
plant, suggesting an impact of the municipal effluent on redox
homeostasis. Transcriptomic results indicated the downregulation
of genes related to lipid, glucose, and retinoid in
southern Lake St. Pierre as well as a decrease in retinoid storage.
Overall, biochemical and molecular markers indicated
that the health status of yellow perch followed a decreasing
gradient from upstream to downstream of the St. Lawrence
River. This gradient is representative of the cumulative negative
impacts of human activities on water and habitat quality
along the river.
the health of yellow perch (Perca flavescens) in the St.
Lawrence River (Quebec, Canada), which is experiencing a
severe population decline in the downstream portion of the
river. Physiological parameters, liver alterations, trace metal
concentrations, parasite prevalence and abundance, stable isotope
composition, and the presence/absence of the viral
hemorragic septicemia virus (VHSV) were evaluated in perch
collected at six sites along the river: Lake St. François, Lake
St. Louis (north and south), Beauregard Island, and Lake St.
Pierre (north and south). Trace metal concentrations in surface
water were higher in Lake St. Louis and downstream of a
major urban wastewater treatment plant discharge, indicating
that this effluent was a significant source of Cu, As, Ag, Zn,
and Cd. Levels of Pb in surface water exceeded thresholds for
the protection of aquatic life in Lake St. Louis and were negatively
correlated with body condition index in this lake. In
Lake St. Pierre, Cu, Ag, and Cd bioaccumulated significantly
in perch liver and lower body condition index and greater liver
damage were observed compared to upstream sites. Parasite
analyses indicated a higher abundance of metacercariae of the
trematodes Apophallus brevis and Diplostomum spp. in Lake
St. Louis, and VHSV was not detected in the liver of yellow
perch for all studied sites. Overall, results suggested that the
global health of yellow perch from Lake St. Pierre is lower
compared to upstream studied sites, which could contribute to
the documented population collapse at this site.
high production volume used in a broad range of applications. The use of TBOEP containing products has resulted in its release and ubiquitous occurrence in the aquatic environment. In this study, Daphnia magna transcriptomic response was measured by microarray to evaluate sublethal effects of TBOEP as part of a multi-level biological approach including specific gene transcription measured by qRT-PCR, enzyme activity, and life-history endpoints (i.e., survival, growth and reproduction). Chronic exposure (21 d) to a range of sublethal concentrations of TBOEP (14.7–1470 lg L1) did not impact growth, survival or reproduction, although the number of offspring decreased between the lowest and the highest dose. Gene transcription profiling by microarray analysis revealed that 101 genes were differentially transcribed in response to TBOEP (fold change treated/control ±1, p < 0.05). Most of the responding genes were involved in protein metabolism (9), biosynthesis (4) and energy metabolism (6) indicating that TBOEP could have chronic toxic effects on aquatic organisms at sublethal doses by disrupting essential biological pathways. Nine genes were found to be commonly affected by more than one dose, including a gene coding for cathepsin D and multiple isoforms of genes coding for hemoglobin, suggesting potential biomarkers of interest. Microarray results were confirmed by qRT-PCR and measurements at the protein level as cathepsin D enzymatic activity increased significantly in the highest dose treatment. Results highlight the relevance of using the transcriptomic response of D. magna as a first line of evidence to unravel the mode of action of chemicals.