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Martin Grosell - One of the best experts on this subject based on the ideXlab platform.
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comparative evaluation of na uptake in Cyprinodon variegatus variegatus lacepede and Cyprinodon variegatus hubbsi carr Cyprinodontiformes teleostei evaluation of nhe function in high and low na freshwater
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2015Co-Authors: Kevin V. Brix, Andrew J. Esbaugh, Edward M. Mager, Martin GrosellAbstract:Abstract The euryhaline pupfish, Cyprinodon variegatus variegatus ( Cvv ), can successfully osmoregulate in ≥ 2mM Na + and a freshwater population ( Cyprinodon variegatus hubbsi; Cvh ) osmoregulates at ≥ 0.1mM Na + . We previously demonstrated that Cvv relies on an apical NKCC and NHE in the gill for Na + uptake in high (7mM) and intermediate (2mM) Na + concentrations, while Cvh relies only on NHE for Na + uptake. This study investigated whether differential NHE isoform use explains differences in Na + uptake kinetics between these two populations. We further studied whether Cvh uses a NHE-Rh metabolon or carbonic anhydrase (CA) to overcome thermodynamic challenges of NHE function in dilute freshwater. Transfer to more dilute freshwater resulted in upregulation of nhe-2 ( Cvv only) and nhe-3 ( Cvv and Cvh ). Relative expression of nhe-3 compared to nhe-2 was 2-fold higher in Cvv , but 200-fold higher in Cvh suggesting that nhe-3 expression is an important freshwater adaptation for Cvh . Simultaneous measurement of Na + and T amm flux under various conditions provided no support for a NHE-Rh metabolon in either population. Carbonic anhydrase activity in Cvv was comparable in 7 and 2mM Na + acclimated fish. In Cvh , CA activity increased by 75% in 0.1mM Na + acclimated fish compared to 7mM Na + fish. Ethoxzolamide had variable effects, stimulating and reducing Na + uptake in Cvv acclimated to 7 and 2mM Na + , while reducing Na + uptake in 7 and 0.1mM Na + acclimated Cvh . This suggests that CA plays important, but different roles in regulating Na + uptake in Cvv and Cvh .
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Comparative evaluation of Na(+) uptake in Cyprinodon variegatus variegatus (Lacepede) and Cyprinodon variegatus hubbsi (Carr) (Cyprinodontiformes, Teleostei): Evaluation of NHE function in high and low Na(+) freshwater.
Comparative biochemistry and physiology. Part A Molecular & integrative physiology, 2015Co-Authors: Kevin V. Brix, Andrew J. Esbaugh, Edward M. Mager, Martin GrosellAbstract:Abstract The euryhaline pupfish, Cyprinodon variegatus variegatus ( Cvv ), can successfully osmoregulate in ≥ 2mM Na + and a freshwater population ( Cyprinodon variegatus hubbsi; Cvh ) osmoregulates at ≥ 0.1mM Na + . We previously demonstrated that Cvv relies on an apical NKCC and NHE in the gill for Na + uptake in high (7mM) and intermediate (2mM) Na + concentrations, while Cvh relies only on NHE for Na + uptake. This study investigated whether differential NHE isoform use explains differences in Na + uptake kinetics between these two populations. We further studied whether Cvh uses a NHE-Rh metabolon or carbonic anhydrase (CA) to overcome thermodynamic challenges of NHE function in dilute freshwater. Transfer to more dilute freshwater resulted in upregulation of nhe-2 ( Cvv only) and nhe-3 ( Cvv and Cvh ). Relative expression of nhe-3 compared to nhe-2 was 2-fold higher in Cvv , but 200-fold higher in Cvh suggesting that nhe-3 expression is an important freshwater adaptation for Cvh . Simultaneous measurement of Na + and T amm flux under various conditions provided no support for a NHE-Rh metabolon in either population. Carbonic anhydrase activity in Cvv was comparable in 7 and 2mM Na + acclimated fish. In Cvh , CA activity increased by 75% in 0.1mM Na + acclimated fish compared to 7mM Na + fish. Ethoxzolamide had variable effects, stimulating and reducing Na + uptake in Cvv acclimated to 7 and 2mM Na + , while reducing Na + uptake in 7 and 0.1mM Na + acclimated Cvh . This suggests that CA plays important, but different roles in regulating Na + uptake in Cvv and Cvh .
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Comparative evaluation of Na+ uptake in Cyprinodon variegatus variegatus (Lacepede) and Cyprinodon variegatus hubbsi (Carr) (Cyprinodontiformes, Teleostei): Evaluation of NHE function in high and low Na+ freshwater Part A Molecular & integrative phys
Comparative Biochemistry and Physiology, 2015Co-Authors: Kevin V. Brix, Andrew J. Esbaugh, Edward M. Mager, Martin GrosellAbstract:The euryhaline pupfish, Cyprinodon variegatus variegatus (Cvv), can successfully osmoregulate in ≥2mM Na+ and a freshwater population (Cyprinodon variegatus hubbsi; Cvh) osmoregulates at ≥0.1mM Na+. We previously demonstrated that Cvv relies on an apical NKCC and NHE in the gill for Na+ uptake in high (7mM) and intermediate (2mM) Na+ concentrations, while Cvh relies only on NHE for Na+ uptake. This study investigated whether differential NHE isoform use explains differences in Na+ uptake kinetics between these two populations. We further studied whether Cvh uses a NHE-Rh metabolon or carbonic anhydrase (CA) to overcome thermodynamic challenges of NHE function in dilute freshwater. Transfer to more dilute freshwater resulted in upregulation of nhe-2 (Cvv only) and nhe-3 (Cvv and Cvh). Relative expression of nhe-3 compared to nhe-2 was 2-fold higher in Cvv, but 200-fold higher in Cvh suggesting that nhe-3 expression is an important freshwater adaptation for Cvh. Simultaneous measurement of Na+ and Tamm flux under various conditions provided no support for a NHE-Rh metabolon in either population. Carbonic anhydrase activity in Cvv was comparable in 7 and 2mM Na+ acclimated fish. In Cvh, CA activity increased by 75% in 0.1mM Na+ acclimated fish compared to 7mM Na+ fish. Ethoxzolamide had variable effects, stimulating and reducing Na+ uptake in Cvv acclimated to 7 and 2mM Na+, while reducing Na+ uptake in 7 and 0.1mM Na+ acclimated Cvh. This suggests that CA plays important, but different roles in regulating Na+ uptake in Cvv and Cvh.
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comparative characterization of na transport in Cyprinodon variegatus variegatus and Cyprinodon variegatus hubbsi a model species complex for studying teleost invasion of freshwater
The Journal of Experimental Biology, 2012Co-Authors: Kevin V. Brix, Martin GrosellAbstract:The euryhaline fish Cyprinodon variegatus variegatus is capable of tolerating ambient salinities ranging from 0.3 to 160 PSU, but is incapable of long-term survival in freshwater (<2 mmol l(-1) Na(+)). A population isolated in several freshwater (0.4-1 mmol l(-1) Na(+)) lakes in central Florida is now designated as a subspecies (Cyprinodon variegatus hubbsi). We conducted a comparative study of Na(+) transport kinetics in these two populations when acclimated to different ambient Na(+) concentrations. Results reveal that the two subspecies have qualitatively similar low affinity Na(+) uptake kinetics (K(m)=7000-38,000 μmol l(-1)) when acclimated to 2 or 7 mmol l(-1) Na(+), but C. v. hubbsi switches to a high affinity system (K(m)=100-140 μmol l(-1)) in low-Na(+) freshwater (≤1 mmol l(-1) Na(+)). Inhibitor experiments indicate that Na(+) uptake in both subspecies is EIPA-sensitive, but sensitivity decreases with increasing external Na(+). EIPA induced a 95% inhibition of Na(+) influx in C. v. hubbsi acclimated to 0.1 mmol l(-1) Na(+), suggesting that this subspecies is utilizing a Na(+)/H(+) exchanger to take up Na(+) in low-Na(+) environments despite theoretical thermodynamic constraints. Na(+) uptake in C. v. hubbsi acclimated to 0.1 mmol l(-1) Na(+) is phenamil-sensitive but not bafilomycin-sensitive, leading to uncertainty about whether this subspecies also utilizes Na(+) channels for Na(+) uptake. Experiments with both subspecies acclimated to 7 mmol l(-1) Na(+) also indicate that a Cl(-)-dependent Na(+) uptake pathway is present. This pathway is not metolazone-sensitive (NCC inhibitor) in either species but is bumetanide-sensitive in C. v. variegatus but not C. v. hubbsi. This suggests that an apical NKCC is increasingly involved with Na(+) uptake for this subspecies as external Na(+) increases. Finally, characterization of mitochondria-rich cell (MRC) size and density in fish acclimated to different ambient Na(+) concentrations revealed significant increases in the number and size of emergent MRCs with decreasing ambient Na(+). A linear relationship between the fractional area of emergent MRCs and Na(+) uptake rate was observed for both subspecies. However, C. v. variegatus have lower Na(+) uptake rates at a given MRC fractional area compared with C. v. hubbsi, indicating that the enhanced Na(+) uptake by C. v. hubbsi at low ambient Na(+) concentrations is not strictly a result of increased MRC fractional area, and other variables, such as differential expression of proteins involved in Na(+) uptake, must provide C. v. hubbsi with the ability to osmoregulate in dilute freshwater.
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Comparative characterization of Na+ transport in Cyprinodon variegatus variegatus and Cyprinodon variegatus hubbsi: a model species complex for studying teleost invasion of freshwater
Journal of Experimental Biology, 2012Co-Authors: Kevin V. Brix, Martin GrosellAbstract:The euryhaline fish Cyprinodon variegatus variegatus is capable of tolerating ambient salinities ranging from 0.3 to 160 PSU, but is incapable of long-term survival in freshwater (
Kevin V. Brix - One of the best experts on this subject based on the ideXlab platform.
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The effect of temperature acclimation on thermal tolerance, hypoxia tolerance and aerobic scope in two subspecies of sheepshead minnow; Cyprinodon variegatus variegatus and Cyprinodon variegatus hubbsi.
Comparative biochemistry and physiology. Part A Molecular & integrative physiology, 2019Co-Authors: Ellen H. Jung, Kevin V. Brix, Colin J. BraunerAbstract:Abstract The freshwater teleost Cyprinodon variegatus hubbsi (Cvh) diverged from its euryhaline relative Cyprinodon variegatus variegatus (Cvv) ~150 kya and these subspecies are physiologically distinct in their osmoregulatory capabilities. Cvv inhabits intertidal estuaries and saltwater marshes along the Gulf of Mexico and Atlantic coast, where they experience a broad temperature range from −1.9 to 43 °C and frequent bouts of hypoxia. In contrast, Cvh lives in several lakes in central Florida, where temperature is more stable (12–31 °C) and hypoxia is uncommon. To assess whether relaxed selective pressure on Cvh has resulted in reduced temperature and hypoxia tolerance, a comparative study on the effects of acclimation to 25, 30 and 35 °C on critical thermal tolerance (CTMax), hypoxia tolerance, and aerobic scope was performed. The CTMax was similar between subspecies and positively correlated with acclimation temperature. Neither subspecies, however, could survive at 38 °C for a prolonged period of time. In general, Cvv displayed greater hypoxia tolerance and aerobic scope relative to Cvh over the range of acclimation temperatures. Routine metabolic rate was significantly lower while maximum metabolic rate and aerobic scope were significantly higher in Cvv, but only in fish acclimated to 30 °C. Overall, the different responses of Cvh to relaxed selective pressure suggest these traits are weakly linked physiologically in these fishes.
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comparative evaluation of na uptake in Cyprinodon variegatus variegatus lacepede and Cyprinodon variegatus hubbsi carr Cyprinodontiformes teleostei evaluation of nhe function in high and low na freshwater
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2015Co-Authors: Kevin V. Brix, Andrew J. Esbaugh, Edward M. Mager, Martin GrosellAbstract:Abstract The euryhaline pupfish, Cyprinodon variegatus variegatus ( Cvv ), can successfully osmoregulate in ≥ 2mM Na + and a freshwater population ( Cyprinodon variegatus hubbsi; Cvh ) osmoregulates at ≥ 0.1mM Na + . We previously demonstrated that Cvv relies on an apical NKCC and NHE in the gill for Na + uptake in high (7mM) and intermediate (2mM) Na + concentrations, while Cvh relies only on NHE for Na + uptake. This study investigated whether differential NHE isoform use explains differences in Na + uptake kinetics between these two populations. We further studied whether Cvh uses a NHE-Rh metabolon or carbonic anhydrase (CA) to overcome thermodynamic challenges of NHE function in dilute freshwater. Transfer to more dilute freshwater resulted in upregulation of nhe-2 ( Cvv only) and nhe-3 ( Cvv and Cvh ). Relative expression of nhe-3 compared to nhe-2 was 2-fold higher in Cvv , but 200-fold higher in Cvh suggesting that nhe-3 expression is an important freshwater adaptation for Cvh . Simultaneous measurement of Na + and T amm flux under various conditions provided no support for a NHE-Rh metabolon in either population. Carbonic anhydrase activity in Cvv was comparable in 7 and 2mM Na + acclimated fish. In Cvh , CA activity increased by 75% in 0.1mM Na + acclimated fish compared to 7mM Na + fish. Ethoxzolamide had variable effects, stimulating and reducing Na + uptake in Cvv acclimated to 7 and 2mM Na + , while reducing Na + uptake in 7 and 0.1mM Na + acclimated Cvh . This suggests that CA plays important, but different roles in regulating Na + uptake in Cvv and Cvh .
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Comparative evaluation of Na(+) uptake in Cyprinodon variegatus variegatus (Lacepede) and Cyprinodon variegatus hubbsi (Carr) (Cyprinodontiformes, Teleostei): Evaluation of NHE function in high and low Na(+) freshwater.
Comparative biochemistry and physiology. Part A Molecular & integrative physiology, 2015Co-Authors: Kevin V. Brix, Andrew J. Esbaugh, Edward M. Mager, Martin GrosellAbstract:Abstract The euryhaline pupfish, Cyprinodon variegatus variegatus ( Cvv ), can successfully osmoregulate in ≥ 2mM Na + and a freshwater population ( Cyprinodon variegatus hubbsi; Cvh ) osmoregulates at ≥ 0.1mM Na + . We previously demonstrated that Cvv relies on an apical NKCC and NHE in the gill for Na + uptake in high (7mM) and intermediate (2mM) Na + concentrations, while Cvh relies only on NHE for Na + uptake. This study investigated whether differential NHE isoform use explains differences in Na + uptake kinetics between these two populations. We further studied whether Cvh uses a NHE-Rh metabolon or carbonic anhydrase (CA) to overcome thermodynamic challenges of NHE function in dilute freshwater. Transfer to more dilute freshwater resulted in upregulation of nhe-2 ( Cvv only) and nhe-3 ( Cvv and Cvh ). Relative expression of nhe-3 compared to nhe-2 was 2-fold higher in Cvv , but 200-fold higher in Cvh suggesting that nhe-3 expression is an important freshwater adaptation for Cvh . Simultaneous measurement of Na + and T amm flux under various conditions provided no support for a NHE-Rh metabolon in either population. Carbonic anhydrase activity in Cvv was comparable in 7 and 2mM Na + acclimated fish. In Cvh , CA activity increased by 75% in 0.1mM Na + acclimated fish compared to 7mM Na + fish. Ethoxzolamide had variable effects, stimulating and reducing Na + uptake in Cvv acclimated to 7 and 2mM Na + , while reducing Na + uptake in 7 and 0.1mM Na + acclimated Cvh . This suggests that CA plays important, but different roles in regulating Na + uptake in Cvv and Cvh .
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Comparative evaluation of Na+ uptake in Cyprinodon variegatus variegatus (Lacepede) and Cyprinodon variegatus hubbsi (Carr) (Cyprinodontiformes, Teleostei): Evaluation of NHE function in high and low Na+ freshwater Part A Molecular & integrative phys
Comparative Biochemistry and Physiology, 2015Co-Authors: Kevin V. Brix, Andrew J. Esbaugh, Edward M. Mager, Martin GrosellAbstract:The euryhaline pupfish, Cyprinodon variegatus variegatus (Cvv), can successfully osmoregulate in ≥2mM Na+ and a freshwater population (Cyprinodon variegatus hubbsi; Cvh) osmoregulates at ≥0.1mM Na+. We previously demonstrated that Cvv relies on an apical NKCC and NHE in the gill for Na+ uptake in high (7mM) and intermediate (2mM) Na+ concentrations, while Cvh relies only on NHE for Na+ uptake. This study investigated whether differential NHE isoform use explains differences in Na+ uptake kinetics between these two populations. We further studied whether Cvh uses a NHE-Rh metabolon or carbonic anhydrase (CA) to overcome thermodynamic challenges of NHE function in dilute freshwater. Transfer to more dilute freshwater resulted in upregulation of nhe-2 (Cvv only) and nhe-3 (Cvv and Cvh). Relative expression of nhe-3 compared to nhe-2 was 2-fold higher in Cvv, but 200-fold higher in Cvh suggesting that nhe-3 expression is an important freshwater adaptation for Cvh. Simultaneous measurement of Na+ and Tamm flux under various conditions provided no support for a NHE-Rh metabolon in either population. Carbonic anhydrase activity in Cvv was comparable in 7 and 2mM Na+ acclimated fish. In Cvh, CA activity increased by 75% in 0.1mM Na+ acclimated fish compared to 7mM Na+ fish. Ethoxzolamide had variable effects, stimulating and reducing Na+ uptake in Cvv acclimated to 7 and 2mM Na+, while reducing Na+ uptake in 7 and 0.1mM Na+ acclimated Cvh. This suggests that CA plays important, but different roles in regulating Na+ uptake in Cvv and Cvh.
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comparative characterization of na transport in Cyprinodon variegatus variegatus and Cyprinodon variegatus hubbsi a model species complex for studying teleost invasion of freshwater
The Journal of Experimental Biology, 2012Co-Authors: Kevin V. Brix, Martin GrosellAbstract:The euryhaline fish Cyprinodon variegatus variegatus is capable of tolerating ambient salinities ranging from 0.3 to 160 PSU, but is incapable of long-term survival in freshwater (<2 mmol l(-1) Na(+)). A population isolated in several freshwater (0.4-1 mmol l(-1) Na(+)) lakes in central Florida is now designated as a subspecies (Cyprinodon variegatus hubbsi). We conducted a comparative study of Na(+) transport kinetics in these two populations when acclimated to different ambient Na(+) concentrations. Results reveal that the two subspecies have qualitatively similar low affinity Na(+) uptake kinetics (K(m)=7000-38,000 μmol l(-1)) when acclimated to 2 or 7 mmol l(-1) Na(+), but C. v. hubbsi switches to a high affinity system (K(m)=100-140 μmol l(-1)) in low-Na(+) freshwater (≤1 mmol l(-1) Na(+)). Inhibitor experiments indicate that Na(+) uptake in both subspecies is EIPA-sensitive, but sensitivity decreases with increasing external Na(+). EIPA induced a 95% inhibition of Na(+) influx in C. v. hubbsi acclimated to 0.1 mmol l(-1) Na(+), suggesting that this subspecies is utilizing a Na(+)/H(+) exchanger to take up Na(+) in low-Na(+) environments despite theoretical thermodynamic constraints. Na(+) uptake in C. v. hubbsi acclimated to 0.1 mmol l(-1) Na(+) is phenamil-sensitive but not bafilomycin-sensitive, leading to uncertainty about whether this subspecies also utilizes Na(+) channels for Na(+) uptake. Experiments with both subspecies acclimated to 7 mmol l(-1) Na(+) also indicate that a Cl(-)-dependent Na(+) uptake pathway is present. This pathway is not metolazone-sensitive (NCC inhibitor) in either species but is bumetanide-sensitive in C. v. variegatus but not C. v. hubbsi. This suggests that an apical NKCC is increasingly involved with Na(+) uptake for this subspecies as external Na(+) increases. Finally, characterization of mitochondria-rich cell (MRC) size and density in fish acclimated to different ambient Na(+) concentrations revealed significant increases in the number and size of emergent MRCs with decreasing ambient Na(+). A linear relationship between the fractional area of emergent MRCs and Na(+) uptake rate was observed for both subspecies. However, C. v. variegatus have lower Na(+) uptake rates at a given MRC fractional area compared with C. v. hubbsi, indicating that the enhanced Na(+) uptake by C. v. hubbsi at low ambient Na(+) concentrations is not strictly a result of increased MRC fractional area, and other variables, such as differential expression of proteins involved in Na(+) uptake, must provide C. v. hubbsi with the ability to osmoregulate in dilute freshwater.
Das Krishna - One of the best experts on this subject based on the ideXlab platform.
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Post-embryonic development of sheepshead minnow Cyprinodon variegatus: a staging tool based on externally visible anatomical traits
'Springer Science and Business Media LLC', 2017Co-Authors: Schnitzler Joseph, Dussenne Mélanie, Frederich Bruno, Das KrishnaAbstract:peer reviewedThe sheepshead minnow Cyprinodon variegatus has become a favoured model for laboratory studies because of their small size, rapid development, and tolerance of laboratory conditions. Here, we analyse sheepshead minnow post-embryonic development with the goal of providing a generally useful method for staging fish after embryogenesis. Groups of three females and two males were placed in breeding chambers designed for this experiment. More than 100 eggs were collected and maintained in seawater. Embryos were selected under a dissection microscope and placed in incubation dishes (50 per dish) at 26 °C. On day six, embryos hatched and larvae were transferred to 1 L beakers. To define a simplified normalization table for sheepshead minnow development, we measured each fish for its standard length and examined the fish for four externally evident traits: pigmentation pattern, caudal fin morphology, anal fin morphology, and dorsal fin morphology. The four traits were chosen, because they are easily visualized with standard laboratory equipment such as the stereomicroscope and camera. We have provided criteria for staging sheepshead minnows in studies of post-embryonic development. Our data suggest that dorsal and anal fin morphology may serve as a useful phenotype for defining metamorphic climax stages throughout post-embryonic development in C. variegatus. The staging systems we propose should facilitate detailed anatomical and developmental analyses in relation to ecotoxicological studies on potential disruption of the thyroid axis by xenobiotics and endocrine-disrupting compounds
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Triclosan exposure results in alterations of thyroid hormone status and retarded early development and metamorphosis in Cyprinodon variegatus
'Elsevier BV', 2016Co-Authors: Schnitzler Joseph, Dussenne Mélanie, Frederich Bruno, Silvestre Frédéric, Klaren Peter, Das KrishnaAbstract:peer reviewedaudience: researcher, professional, studentThyroid hormones are critically involved in somatic growth, development and metamorphosis of vertebrates. The structural similarity between thyroid hormones and triclosan, an antimicrobial compound widely employed in consumer personal care products, suggests triclosan can have adverse effects on the thyroid system. The sheepshead minnow, Cyprinodon variegatus, is now used in ecotoxicological studies that have recently begun to focus on potential disruption of the thyroid axis by endocrine disrupting compounds. Here, we investigate the in vivo effects of exposure to triclosan (20, 50, and 100 μg L−1) on the thyroid system and the embryonic and larval development of C. variegatus. Triclosan exposure did not affect hatching success, but delayed hatching time by 6–13 h compared to control embryos. Triclosan exposure affected the ontogenetic variations of whole body thyroid hormone concentrations during the larval phase. The T3 peak around 12–15 dph, described to be indicative for the metamorphosis climax in C. variegatus, was absent in triclosan-exposed larvae. Triclosan exposure did not produce any deformity or allometric repatterning, but a delayed development of 18–32 h was observed. We conclude that the triclosan-induced disruption of the thyroid system delays in vivo the start of metamorphosis in our experimental model. We observed a global developmental delay of 24–45 h, equivalent to 4–7% prolongation of the developmental time in C. variegatus. The costs of delayed metamorphosis can lead to reduction of juvenile fitness and could be a determining factor in the outcome of competitive interactions.FRFC n◦ 2.4635.1
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Triclosan exposure results in alterations of thyroid hormone status and retarded early development and metamorphosis in Cyprinodon variegatus
'Elsevier BV', 2016Co-Authors: Schnitzler Joseph, Dussenne Mélanie, Frederich Bruno, Silvestre Frédéric, Klaren Peter, Das KrishnaAbstract:Thyroid hormones are critically involved in somatic growth, development and metamorphosis of vertebrates. The structural similarity between thyroid hormones and triclosan, an antimicrobial compound widely employed in consumer personal care products, suggests triclosan can have adverse effects on the thyroid system. The sheepshead minnow, Cyprinodon variegatus, is now used in ecotoxicological studies that have recently begun to focus on potential disruption of the thyroid axis by endocrine disrupting compounds. Here, we investigate the in vivo effects of exposure to triclosan (20, 50, and 100 μg L−1) on the thyroid system and the embryonic and larval development of C. variegatus. Triclosan exposure did not affect hatching success, but delayed hatching time by 6–13 h compared to control embryos. Triclosan exposure affected the ontogenetic variations of whole body thyroid hormone concentrations during the larval phase. The T3 peak around 12–15 dph, described to be indicative for the metamorphosis climax in C. variegatus, was absent in triclosan-exposed larvae. Triclosan exposure did not produce any deformity or allometric repatterning, but a delayed development of 18–32 h was observed. We conclude that the triclosan-induced disruption of the thyroid system delays in vivo the start of metamorphosis in our experimental model. We observed a global developmental delay of 24–45 h, equivalent to 4–7% prolongation of the developmental time in C. variegatus. The costs of delayed metamorphosis can lead to reduction of juvenile fitness and could be a determining factor in the outcome of competitive interactions.Peer reviewe
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Triclosan retardes development of Sheepshead minnow (Cyprinodon variegatus)
2015Co-Authors: Dussenne Mélanie, Frederich Bruno, Das Krishna, Schnitzler JosephAbstract:The aquatic environment represents the final sink for many chemicals, including bactericidal agents. Among them Triclosan (TCS), with his chemical structure similar to thyroid hormones (THs), may have adverse effects on the thyroid system. The study we carried out aims to evaluate the effects of TCS exposure on development of Cyprinodon variegatus, a fish model used in ecotoxicological studies. We investigated the potential effects of TCS on C. variegatus during two key periods; embryonic development and metamorphosis. We exposed eggs and larvae to environmental relevant concentrations. We showed that TCS had no effect on reproduction parameters, such as egg fertility or survival rate of larvae. However, we highlighted the fact that hatching of exposed larvae was delayed of around 6 to 13 hours compared to control embryos. During the larval phase, measurements of THs levels were performed. We showed that TCS affected the typical ontogenic variations of the whole body thyroid hormones concentrations during metamorphosis. As THs are known to control somatic growth and development, we tested the effects of TCS exposure on morphological development. We observed no deformity or malformation, but we revealed a developmental retardation in larvae exposed to TCS, of around 18 to 32 hours. Such a developmental delay had never been highlighted in previous studies on TCS exposed fish. We hypothesize that the disruption of THs homeostasis affects the timing of the start of metamorphosis. As a consequence, exposed larvae showed an extended larval phase compared to the control group. The harmful effects of TCS on physiology and development are a major concern, as marine organisms are constantly exposed to it. Furthermore, strong connections exist between thyroid and reproductive system, which might have deleterious effects on population dynamics.Peer reviewe
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Triclosan retardes development of Sheepshead minnow (Cyprinodon variegatus)
2015Co-Authors: Dussenne Mélanie, Frederich Bruno, Das Krishna, Schnitzler JosephAbstract:peer reviewedaudience: researcher, professional, studentThe aquatic environment represents the final sink for many chemicals, including bactericidal agents. Among them Triclosan (TCS), with his chemical structure similar to thyroid hormones (THs), may have adverse effects on the thyroid system. The study we carried out aims to evaluate the effects of TCS exposure on development of Cyprinodon variegatus, a fish model used in ecotoxicological studies. We investigated the potential effects of TCS on C. variegatus during two key periods; embryonic development and metamorphosis. We exposed eggs and larvae to environmental relevant concentrations. We showed that TCS had no effect on reproduction parameters, such as egg fertility or survival rate of larvae. However, we highlighted the fact that hatching of exposed larvae was delayed of around 6 to 13 hours compared to control embryos. During the larval phase, measurements of THs levels were performed. We showed that TCS affected the typical ontogenic variations of the whole body thyroid hormones concentrations during metamorphosis. As THs are known to control somatic growth and development, we tested the effects of TCS exposure on morphological development. We observed no deformity or malformation, but we revealed a developmental retardation in larvae exposed to TCS, of around 18 to 32 hours. Such a developmental delay had never been highlighted in previous studies on TCS exposed fish. We hypothesize that the disruption of THs homeostasis affects the timing of the start of metamorphosis. As a consequence, exposed larvae showed an extended larval phase compared to the control group. The harmful effects of TCS on physiology and development are a major concern, as marine organisms are constantly exposed to it. Furthermore, strong connections exist between thyroid and reproductive system, which might have deleterious effects on population dynamics
Schnitzler Joseph - One of the best experts on this subject based on the ideXlab platform.
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Post-embryonic development of sheepshead minnow Cyprinodon variegatus: a staging tool based on externally visible anatomical traits
'Springer Science and Business Media LLC', 2017Co-Authors: Schnitzler Joseph, Dussenne Mélanie, Frederich Bruno, Das KrishnaAbstract:peer reviewedThe sheepshead minnow Cyprinodon variegatus has become a favoured model for laboratory studies because of their small size, rapid development, and tolerance of laboratory conditions. Here, we analyse sheepshead minnow post-embryonic development with the goal of providing a generally useful method for staging fish after embryogenesis. Groups of three females and two males were placed in breeding chambers designed for this experiment. More than 100 eggs were collected and maintained in seawater. Embryos were selected under a dissection microscope and placed in incubation dishes (50 per dish) at 26 °C. On day six, embryos hatched and larvae were transferred to 1 L beakers. To define a simplified normalization table for sheepshead minnow development, we measured each fish for its standard length and examined the fish for four externally evident traits: pigmentation pattern, caudal fin morphology, anal fin morphology, and dorsal fin morphology. The four traits were chosen, because they are easily visualized with standard laboratory equipment such as the stereomicroscope and camera. We have provided criteria for staging sheepshead minnows in studies of post-embryonic development. Our data suggest that dorsal and anal fin morphology may serve as a useful phenotype for defining metamorphic climax stages throughout post-embryonic development in C. variegatus. The staging systems we propose should facilitate detailed anatomical and developmental analyses in relation to ecotoxicological studies on potential disruption of the thyroid axis by xenobiotics and endocrine-disrupting compounds
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Triclosan exposure results in alterations of thyroid hormone status and retarded early development and metamorphosis in Cyprinodon variegatus
'Elsevier BV', 2016Co-Authors: Schnitzler Joseph, Dussenne Mélanie, Frederich Bruno, Silvestre Frédéric, Klaren Peter, Das KrishnaAbstract:peer reviewedaudience: researcher, professional, studentThyroid hormones are critically involved in somatic growth, development and metamorphosis of vertebrates. The structural similarity between thyroid hormones and triclosan, an antimicrobial compound widely employed in consumer personal care products, suggests triclosan can have adverse effects on the thyroid system. The sheepshead minnow, Cyprinodon variegatus, is now used in ecotoxicological studies that have recently begun to focus on potential disruption of the thyroid axis by endocrine disrupting compounds. Here, we investigate the in vivo effects of exposure to triclosan (20, 50, and 100 μg L−1) on the thyroid system and the embryonic and larval development of C. variegatus. Triclosan exposure did not affect hatching success, but delayed hatching time by 6–13 h compared to control embryos. Triclosan exposure affected the ontogenetic variations of whole body thyroid hormone concentrations during the larval phase. The T3 peak around 12–15 dph, described to be indicative for the metamorphosis climax in C. variegatus, was absent in triclosan-exposed larvae. Triclosan exposure did not produce any deformity or allometric repatterning, but a delayed development of 18–32 h was observed. We conclude that the triclosan-induced disruption of the thyroid system delays in vivo the start of metamorphosis in our experimental model. We observed a global developmental delay of 24–45 h, equivalent to 4–7% prolongation of the developmental time in C. variegatus. The costs of delayed metamorphosis can lead to reduction of juvenile fitness and could be a determining factor in the outcome of competitive interactions.FRFC n◦ 2.4635.1
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Triclosan exposure results in alterations of thyroid hormone status and retarded early development and metamorphosis in Cyprinodon variegatus
'Elsevier BV', 2016Co-Authors: Schnitzler Joseph, Dussenne Mélanie, Frederich Bruno, Silvestre Frédéric, Klaren Peter, Das KrishnaAbstract:Thyroid hormones are critically involved in somatic growth, development and metamorphosis of vertebrates. The structural similarity between thyroid hormones and triclosan, an antimicrobial compound widely employed in consumer personal care products, suggests triclosan can have adverse effects on the thyroid system. The sheepshead minnow, Cyprinodon variegatus, is now used in ecotoxicological studies that have recently begun to focus on potential disruption of the thyroid axis by endocrine disrupting compounds. Here, we investigate the in vivo effects of exposure to triclosan (20, 50, and 100 μg L−1) on the thyroid system and the embryonic and larval development of C. variegatus. Triclosan exposure did not affect hatching success, but delayed hatching time by 6–13 h compared to control embryos. Triclosan exposure affected the ontogenetic variations of whole body thyroid hormone concentrations during the larval phase. The T3 peak around 12–15 dph, described to be indicative for the metamorphosis climax in C. variegatus, was absent in triclosan-exposed larvae. Triclosan exposure did not produce any deformity or allometric repatterning, but a delayed development of 18–32 h was observed. We conclude that the triclosan-induced disruption of the thyroid system delays in vivo the start of metamorphosis in our experimental model. We observed a global developmental delay of 24–45 h, equivalent to 4–7% prolongation of the developmental time in C. variegatus. The costs of delayed metamorphosis can lead to reduction of juvenile fitness and could be a determining factor in the outcome of competitive interactions.Peer reviewe
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Triclosan retardes development of Sheepshead minnow (Cyprinodon variegatus)
2015Co-Authors: Dussenne Mélanie, Frederich Bruno, Das Krishna, Schnitzler JosephAbstract:The aquatic environment represents the final sink for many chemicals, including bactericidal agents. Among them Triclosan (TCS), with his chemical structure similar to thyroid hormones (THs), may have adverse effects on the thyroid system. The study we carried out aims to evaluate the effects of TCS exposure on development of Cyprinodon variegatus, a fish model used in ecotoxicological studies. We investigated the potential effects of TCS on C. variegatus during two key periods; embryonic development and metamorphosis. We exposed eggs and larvae to environmental relevant concentrations. We showed that TCS had no effect on reproduction parameters, such as egg fertility or survival rate of larvae. However, we highlighted the fact that hatching of exposed larvae was delayed of around 6 to 13 hours compared to control embryos. During the larval phase, measurements of THs levels were performed. We showed that TCS affected the typical ontogenic variations of the whole body thyroid hormones concentrations during metamorphosis. As THs are known to control somatic growth and development, we tested the effects of TCS exposure on morphological development. We observed no deformity or malformation, but we revealed a developmental retardation in larvae exposed to TCS, of around 18 to 32 hours. Such a developmental delay had never been highlighted in previous studies on TCS exposed fish. We hypothesize that the disruption of THs homeostasis affects the timing of the start of metamorphosis. As a consequence, exposed larvae showed an extended larval phase compared to the control group. The harmful effects of TCS on physiology and development are a major concern, as marine organisms are constantly exposed to it. Furthermore, strong connections exist between thyroid and reproductive system, which might have deleterious effects on population dynamics.Peer reviewe
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Triclosan retardes development of Sheepshead minnow (Cyprinodon variegatus)
2015Co-Authors: Dussenne Mélanie, Frederich Bruno, Das Krishna, Schnitzler JosephAbstract:peer reviewedaudience: researcher, professional, studentThe aquatic environment represents the final sink for many chemicals, including bactericidal agents. Among them Triclosan (TCS), with his chemical structure similar to thyroid hormones (THs), may have adverse effects on the thyroid system. The study we carried out aims to evaluate the effects of TCS exposure on development of Cyprinodon variegatus, a fish model used in ecotoxicological studies. We investigated the potential effects of TCS on C. variegatus during two key periods; embryonic development and metamorphosis. We exposed eggs and larvae to environmental relevant concentrations. We showed that TCS had no effect on reproduction parameters, such as egg fertility or survival rate of larvae. However, we highlighted the fact that hatching of exposed larvae was delayed of around 6 to 13 hours compared to control embryos. During the larval phase, measurements of THs levels were performed. We showed that TCS affected the typical ontogenic variations of the whole body thyroid hormones concentrations during metamorphosis. As THs are known to control somatic growth and development, we tested the effects of TCS exposure on morphological development. We observed no deformity or malformation, but we revealed a developmental retardation in larvae exposed to TCS, of around 18 to 32 hours. Such a developmental delay had never been highlighted in previous studies on TCS exposed fish. We hypothesize that the disruption of THs homeostasis affects the timing of the start of metamorphosis. As a consequence, exposed larvae showed an extended larval phase compared to the control group. The harmful effects of TCS on physiology and development are a major concern, as marine organisms are constantly exposed to it. Furthermore, strong connections exist between thyroid and reproductive system, which might have deleterious effects on population dynamics
K V Brix - One of the best experts on this subject based on the ideXlab platform.
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evaluation of pre and post zygotic mating barriers hybrid fitness and phylogenetic relationship between Cyprinodon variegatus variegatus and Cyprinodon variegatus hubbsi Cyprinodontiformes teleostei
Journal of Evolutionary Biology, 2013Co-Authors: K V Brix, M GrosellAbstract:The euryhaline fish Cyprinodon variegatus variegatus (Cvv) is capable of tolerating ambient salinities ranging from 0.3 to 167 g l 1 , but incapable of longterm survival in freshwater (< 2m M Na + ). However, a population of this species, now designated as a subspecies (Cyprinodon variegatus hubbsi; Cvh), has been isolated in several freshwater (0.4– 1m M Na + ) lakes in central Florida for the past ~150 ky. We previously demonstrated that Cvh has a significantly higher affinity for Na + uptake suggesting that it has adapted to its dilute freshwater environment. We here evaluate whether Cvh should be considered a separate species by characterizing pre- and post-zygotic isolation, Na + transport characteristics of the two populations and their hybrids, and developing a molecular phylogeny of Cvv and Cvh populations in Florida using mtDNA sequence data. We found evidence of partial prezygotic isolation with Cvv females mating almost exclusively (89%) with con-specific males in choice mating experiments. Partial post-zygotic isolation was also observed with significant (59–89%) reductions in hatching success of hybrid embryos compared with con-specific embryos. Na + uptake kinetics in hybrids (both Cvv x Cvh and Cvh x Cvv) bred and raised under common garden conditions were intermediate to Cvh (high affinity) and Cvv (low affinity) indicating that observed differences are genetically based. Similar observations were made with respect to short-term (96 h) survival of juveniles acutely transferred from 7 mM Na + to a range of more dilute (0.1– 2m M Na + ) freshwater. Finally, although phylogenetic analysis of Cvv and Cvh populations using mtDNA sequence for ND2 were unable to fully resolve a polytomy between Cvh and Cvv populations from northeastern Florida, these data do not falsify the hypothesis that Cvh is of monophyletic origin. Overall, the available data suggest that Cvh should be considered a separate species or at a minimum an evolutionarily significant unit.
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Evaluation of pre‐ and post‐zygotic mating barriers, hybrid fitness and phylogenetic relationship between Cyprinodon variegatus variegatus and Cyprinodon variegatus hubbsi (Cyprinodontiformes, Teleostei)
Journal of evolutionary biology, 2013Co-Authors: K V Brix, M GrosellAbstract:The euryhaline fish Cyprinodon variegatus variegatus (Cvv) is capable of tolerating ambient salinities ranging from 0.3 to 167 g l 1 , but incapable of longterm survival in freshwater (< 2m M Na + ). However, a population of this species, now designated as a subspecies (Cyprinodon variegatus hubbsi; Cvh), has been isolated in several freshwater (0.4– 1m M Na + ) lakes in central Florida for the past ~150 ky. We previously demonstrated that Cvh has a significantly higher affinity for Na + uptake suggesting that it has adapted to its dilute freshwater environment. We here evaluate whether Cvh should be considered a separate species by characterizing pre- and post-zygotic isolation, Na + transport characteristics of the two populations and their hybrids, and developing a molecular phylogeny of Cvv and Cvh populations in Florida using mtDNA sequence data. We found evidence of partial prezygotic isolation with Cvv females mating almost exclusively (89%) with con-specific males in choice mating experiments. Partial post-zygotic isolation was also observed with significant (59–89%) reductions in hatching success of hybrid embryos compared with con-specific embryos. Na + uptake kinetics in hybrids (both Cvv x Cvh and Cvh x Cvv) bred and raised under common garden conditions were intermediate to Cvh (high affinity) and Cvv (low affinity) indicating that observed differences are genetically based. Similar observations were made with respect to short-term (96 h) survival of juveniles acutely transferred from 7 mM Na + to a range of more dilute (0.1– 2m M Na + ) freshwater. Finally, although phylogenetic analysis of Cvv and Cvh populations using mtDNA sequence for ND2 were unable to fully resolve a polytomy between Cvh and Cvv populations from northeastern Florida, these data do not falsify the hypothesis that Cvh is of monophyletic origin. Overall, the available data suggest that Cvh should be considered a separate species or at a minimum an evolutionarily significant unit.
