The Experts below are selected from a list of 62433 Experts worldwide ranked by ideXlab platform
Sean W Kennedy - One of the best experts on this subject based on the ideXlab platform.
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a luciferase reporter gene assay and aryl hydrocarbon receptor 1 genotype predict the ld50 of polychlorinated biphenyls in Avian Species
Toxicology and Applied Pharmacology, 2012Co-Authors: Gillian E Manning, Reza Farmahin, Doug Crump, Stephanie P Jones, Jeff Klein, Alex Konstantinov, Dave Potter, Sean W KennedyAbstract:: Birds differ in sensitivity to the embryotoxic effects of polychlorinated biphenyls (PCBs), which complicates environmental risk assessments for these chemicals. Recent research has shown that the identities of amino acid residues 324 and 380 in the Avian aryl hydrocarbon receptor 1 (AHR1) ligand binding domain (LBD) are primarily responsible for differences in Avian Species sensitivity to selected dibenzo-p-dioxins and furans. A luciferase reporter gene (LRG) assay was developed in our laboratory to measure AHR1-mediated induction of a cytochrome P450 1A5 reporter gene in COS-7 cells transfected with different Avian AHR1 constructs. In the present study, the LRG assay was used to measure the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and PCBs 126, 77, 105 and 118 on luciferase activity in COS-7 cells transfected with AHR1 constructs representative of 86 Avian Species in order to predict their sensitivity to PCB-induced embryolethality and the relative potency of PCBs in these Species. The results of the LRG assay indicate that the identity of amino acid residues 324 and 380 in the AHR1 LBD are the major determinants of Avian Species sensitivity to PCBs. The relative potency of PCBs did not differ greatly among AHR1 constructs. Luciferase activity was significantly correlated with embryolethality data obtained from the literature (R(2)≥0.87, p<0.0001). Thus, the LRG assay in combination with the knowledge of a Species' AHR1 LBD sequence can be used to predict PCB-induced embryolethality in potentially any Avian Species of interest without the use of lethal methods on a large number of individuals.
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a luciferase reporter gene assay and aryl hydrocarbon receptor 1 genotype predict the ld50 of polychlorinated biphenyls in Avian Species
Toxicology and Applied Pharmacology, 2012Co-Authors: Gillian E Manning, Reza Farmahin, Doug Crump, Stephanie P Jones, Jeff Klein, Alex Konstantinov, Dave Potter, Sean W KennedyAbstract:Abstract Birds differ in sensitivity to the embryotoxic effects of polychlorinated biphenyls (PCBs), which complicates environmental risk assessments for these chemicals. Recent research has shown that the identities of amino acid residues 324 and 380 in the Avian aryl hydrocarbon receptor 1 (AHR1) ligand binding domain (LBD) are primarily responsible for differences in Avian Species sensitivity to selected dibenzo-p-dioxins and furans. A luciferase reporter gene (LRG) assay was developed in our laboratory to measure AHR1-mediated induction of a cytochrome P450 1A5 reporter gene in COS-7 cells transfected with different Avian AHR1 constructs. In the present study, the LRG assay was used to measure the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and PCBs 126, 77, 105 and 118 on luciferase activity in COS-7 cells transfected with AHR1 constructs representative of 86 Avian Species in order to predict their sensitivity to PCB-induced embryolethality and the relative potency of PCBs in these Species. The results of the LRG assay indicate that the identity of amino acid residues 324 and 380 in the AHR1 LBD are the major determinants of Avian Species sensitivity to PCBs. The relative potency of PCBs did not differ greatly among AHR1 constructs. Luciferase activity was significantly correlated with embryolethality data obtained from the literature (R2 ≥ 0.87, p
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key amino acids in the aryl hydrocarbon receptor predict dioxin sensitivity in Avian Species
Environmental Science & Technology, 2008Co-Authors: Jessica A Head, Mark E Hahn, Sean W KennedyAbstract:Dioxin-like compounds are toxic to most vertebrates, but significant differences in sensitivity exist among Species. A recent study suggests that the amino acid residues corresponding to Ile324 and Ser380 in the chicken aryl hydrocarbon receptor 1 (AHR1) are important determinants of differential biochemical responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in chickens and common terns. Here, we investigate whether the identity of these amino acid residues can predict embryonic sensitivity to dioxin-like compounds in a wide range of birds. AHR1 sequences were determined in Species for which sensitivity data were available. Of all the Species surveyed, chickens were unique in having the Ile/Ser genotype and were also the most sensitive to dioxin-like compounds. Turkeys, ring-necked pheasants, and Eastern bluebirds (intermediate Ile/Ala genotype) were less sensitive than chickens but more sensitive than American kestrels, common terns, double-crested cormorants, Japanese quail, herring gulls, or ducks (Val/ Ala genotype). Our work suggests that key amino acids in the AHR1 ligand binding domain are predictive of broad categories of dioxin sensitivity in Avian Species. Given the large degree of variation in Species sensitivity and the paucity of Species-specific toxicity data, a genetic screen based on these findings could substantially improve risk assessment for dioxin-like compounds in wild birds.
Reza Farmahin - One of the best experts on this subject based on the ideXlab platform.
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amino acid sequence of the ligand binding domain of the aryl hydrocarbon receptor 1 predicts sensitivity of wild birds to effects of dioxin like compounds
Toxicological Sciences, 2013Co-Authors: Gillian E Manning, Reza Farmahin, Doug Crump, Stephanie P Jones, Mark E Hahn, Lukas J Mundy, Sibel I KarchnerAbstract:The sensitivity of Avian Species to the toxic effects of dioxin-like compounds (DLCs) varies up to 1000-fold among Species, and this variability has been associated with interSpecies differences in aryl hydrocarbon receptor 1 ligand-binding domain (AHR1 LBD) sequence. We previously showed that LD 50 values, based on in ovo exposures to DLCs, were significantly correlated with in vitro EC 50 values obtained with a luciferase reporter gene (LRG) assay that measures AHR1-mediated induction of cytochrome P4501A in COS-7 cells transfected with Avian AHR1 constructs. Those findings suggest that the AHR1 LBD sequence and the LRG assay can be used to predict Avian Species sensitivity to DLCs. In the present study, the AHR1 LBD sequences of 86 Avian Species were studied, and differences at amino acid sites 256, 257, 297, 324, 337, and 380 were identified. Site-directed mutagenesis, the LRG assay, and homology modeling highlighted the importance of each amino acid site in AHR1 sensitivity to 2,3,7,8-tetrachlorodibenzo-p-dioxin and other DLCs. The results of the study revealed that (1) only amino acids at sites 324 and 380 affect the sensitivity of AHR1 expression constructs of the 86 Avian Species to DLCs and (2) in vitro luciferase activity of AHR1 constructs containing only the LBD of the Species of interest is significantly correlated (r 2 = 0.93, p < 0.0001) with in ovo toxicity
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a luciferase reporter gene assay and aryl hydrocarbon receptor 1 genotype predict the ld50 of polychlorinated biphenyls in Avian Species
Toxicology and Applied Pharmacology, 2012Co-Authors: Gillian E Manning, Reza Farmahin, Doug Crump, Stephanie P Jones, Jeff Klein, Alex Konstantinov, Dave Potter, Sean W KennedyAbstract:: Birds differ in sensitivity to the embryotoxic effects of polychlorinated biphenyls (PCBs), which complicates environmental risk assessments for these chemicals. Recent research has shown that the identities of amino acid residues 324 and 380 in the Avian aryl hydrocarbon receptor 1 (AHR1) ligand binding domain (LBD) are primarily responsible for differences in Avian Species sensitivity to selected dibenzo-p-dioxins and furans. A luciferase reporter gene (LRG) assay was developed in our laboratory to measure AHR1-mediated induction of a cytochrome P450 1A5 reporter gene in COS-7 cells transfected with different Avian AHR1 constructs. In the present study, the LRG assay was used to measure the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and PCBs 126, 77, 105 and 118 on luciferase activity in COS-7 cells transfected with AHR1 constructs representative of 86 Avian Species in order to predict their sensitivity to PCB-induced embryolethality and the relative potency of PCBs in these Species. The results of the LRG assay indicate that the identity of amino acid residues 324 and 380 in the AHR1 LBD are the major determinants of Avian Species sensitivity to PCBs. The relative potency of PCBs did not differ greatly among AHR1 constructs. Luciferase activity was significantly correlated with embryolethality data obtained from the literature (R(2)≥0.87, p<0.0001). Thus, the LRG assay in combination with the knowledge of a Species' AHR1 LBD sequence can be used to predict PCB-induced embryolethality in potentially any Avian Species of interest without the use of lethal methods on a large number of individuals.
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a luciferase reporter gene assay and aryl hydrocarbon receptor 1 genotype predict the ld50 of polychlorinated biphenyls in Avian Species
Toxicology and Applied Pharmacology, 2012Co-Authors: Gillian E Manning, Reza Farmahin, Doug Crump, Stephanie P Jones, Jeff Klein, Alex Konstantinov, Dave Potter, Sean W KennedyAbstract:Abstract Birds differ in sensitivity to the embryotoxic effects of polychlorinated biphenyls (PCBs), which complicates environmental risk assessments for these chemicals. Recent research has shown that the identities of amino acid residues 324 and 380 in the Avian aryl hydrocarbon receptor 1 (AHR1) ligand binding domain (LBD) are primarily responsible for differences in Avian Species sensitivity to selected dibenzo-p-dioxins and furans. A luciferase reporter gene (LRG) assay was developed in our laboratory to measure AHR1-mediated induction of a cytochrome P450 1A5 reporter gene in COS-7 cells transfected with different Avian AHR1 constructs. In the present study, the LRG assay was used to measure the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and PCBs 126, 77, 105 and 118 on luciferase activity in COS-7 cells transfected with AHR1 constructs representative of 86 Avian Species in order to predict their sensitivity to PCB-induced embryolethality and the relative potency of PCBs in these Species. The results of the LRG assay indicate that the identity of amino acid residues 324 and 380 in the AHR1 LBD are the major determinants of Avian Species sensitivity to PCBs. The relative potency of PCBs did not differ greatly among AHR1 constructs. Luciferase activity was significantly correlated with embryolethality data obtained from the literature (R2 ≥ 0.87, p
Stephanie P Jones - One of the best experts on this subject based on the ideXlab platform.
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amino acid sequence of the ligand binding domain of the aryl hydrocarbon receptor 1 predicts sensitivity of wild birds to effects of dioxin like compounds
Toxicological Sciences, 2013Co-Authors: Gillian E Manning, Reza Farmahin, Doug Crump, Stephanie P Jones, Mark E Hahn, Lukas J Mundy, Sibel I KarchnerAbstract:The sensitivity of Avian Species to the toxic effects of dioxin-like compounds (DLCs) varies up to 1000-fold among Species, and this variability has been associated with interSpecies differences in aryl hydrocarbon receptor 1 ligand-binding domain (AHR1 LBD) sequence. We previously showed that LD 50 values, based on in ovo exposures to DLCs, were significantly correlated with in vitro EC 50 values obtained with a luciferase reporter gene (LRG) assay that measures AHR1-mediated induction of cytochrome P4501A in COS-7 cells transfected with Avian AHR1 constructs. Those findings suggest that the AHR1 LBD sequence and the LRG assay can be used to predict Avian Species sensitivity to DLCs. In the present study, the AHR1 LBD sequences of 86 Avian Species were studied, and differences at amino acid sites 256, 257, 297, 324, 337, and 380 were identified. Site-directed mutagenesis, the LRG assay, and homology modeling highlighted the importance of each amino acid site in AHR1 sensitivity to 2,3,7,8-tetrachlorodibenzo-p-dioxin and other DLCs. The results of the study revealed that (1) only amino acids at sites 324 and 380 affect the sensitivity of AHR1 expression constructs of the 86 Avian Species to DLCs and (2) in vitro luciferase activity of AHR1 constructs containing only the LBD of the Species of interest is significantly correlated (r 2 = 0.93, p < 0.0001) with in ovo toxicity
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a luciferase reporter gene assay and aryl hydrocarbon receptor 1 genotype predict the ld50 of polychlorinated biphenyls in Avian Species
Toxicology and Applied Pharmacology, 2012Co-Authors: Gillian E Manning, Reza Farmahin, Doug Crump, Stephanie P Jones, Jeff Klein, Alex Konstantinov, Dave Potter, Sean W KennedyAbstract:: Birds differ in sensitivity to the embryotoxic effects of polychlorinated biphenyls (PCBs), which complicates environmental risk assessments for these chemicals. Recent research has shown that the identities of amino acid residues 324 and 380 in the Avian aryl hydrocarbon receptor 1 (AHR1) ligand binding domain (LBD) are primarily responsible for differences in Avian Species sensitivity to selected dibenzo-p-dioxins and furans. A luciferase reporter gene (LRG) assay was developed in our laboratory to measure AHR1-mediated induction of a cytochrome P450 1A5 reporter gene in COS-7 cells transfected with different Avian AHR1 constructs. In the present study, the LRG assay was used to measure the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and PCBs 126, 77, 105 and 118 on luciferase activity in COS-7 cells transfected with AHR1 constructs representative of 86 Avian Species in order to predict their sensitivity to PCB-induced embryolethality and the relative potency of PCBs in these Species. The results of the LRG assay indicate that the identity of amino acid residues 324 and 380 in the AHR1 LBD are the major determinants of Avian Species sensitivity to PCBs. The relative potency of PCBs did not differ greatly among AHR1 constructs. Luciferase activity was significantly correlated with embryolethality data obtained from the literature (R(2)≥0.87, p<0.0001). Thus, the LRG assay in combination with the knowledge of a Species' AHR1 LBD sequence can be used to predict PCB-induced embryolethality in potentially any Avian Species of interest without the use of lethal methods on a large number of individuals.
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a luciferase reporter gene assay and aryl hydrocarbon receptor 1 genotype predict the ld50 of polychlorinated biphenyls in Avian Species
Toxicology and Applied Pharmacology, 2012Co-Authors: Gillian E Manning, Reza Farmahin, Doug Crump, Stephanie P Jones, Jeff Klein, Alex Konstantinov, Dave Potter, Sean W KennedyAbstract:Abstract Birds differ in sensitivity to the embryotoxic effects of polychlorinated biphenyls (PCBs), which complicates environmental risk assessments for these chemicals. Recent research has shown that the identities of amino acid residues 324 and 380 in the Avian aryl hydrocarbon receptor 1 (AHR1) ligand binding domain (LBD) are primarily responsible for differences in Avian Species sensitivity to selected dibenzo-p-dioxins and furans. A luciferase reporter gene (LRG) assay was developed in our laboratory to measure AHR1-mediated induction of a cytochrome P450 1A5 reporter gene in COS-7 cells transfected with different Avian AHR1 constructs. In the present study, the LRG assay was used to measure the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and PCBs 126, 77, 105 and 118 on luciferase activity in COS-7 cells transfected with AHR1 constructs representative of 86 Avian Species in order to predict their sensitivity to PCB-induced embryolethality and the relative potency of PCBs in these Species. The results of the LRG assay indicate that the identity of amino acid residues 324 and 380 in the AHR1 LBD are the major determinants of Avian Species sensitivity to PCBs. The relative potency of PCBs did not differ greatly among AHR1 constructs. Luciferase activity was significantly correlated with embryolethality data obtained from the literature (R2 ≥ 0.87, p
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cytochrome p4501a induction by 2 3 7 8 tetrachlorodibenzo p dioxin and two chlorinated dibenzofurans in primary hepatocyte cultures of three Avian Species
Toxicological Sciences, 2010Co-Authors: Jessica C Herve, John P. Giesy, Doug Crump, Stephanie P Jones, Lukas J Mundy, Matthew J Zwiernik, Steven J Bursian, Paul D Jones, Steve WisemanAbstract:Relative potencies of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), and 2,3,7, 8-tetrachlorodibenzofuran (TCDF) were determined in vitro in primary hepatocyte cultures of chicken (Gallus gallus), ring-necked pheasant (Phasianus colchicus), and Japanese quail (Coturnix japonica) embryos. Concentration-dependent effects on ethoxyresorufin O-deethylase (EROD) activity and expression of cytochrome P4501A4 and cytochrome P4501A5 (CYP1A4 and CYP1A5) messenger RNA (mRNA) were determined in hepatocytes exposed to serial dilutions of TCDD, PeCDF, or TCDF for 24 h. In chicken hepatocytes, the three compounds were equipotent inducers of EROD activity and CYP1A4/CYP1A5 mRNA expression. However, in ring-necked pheasant and Japanese quail hepatocytes, PeCDF was more potent than TCDD (3- to 5-fold in ring-necked pheasant and 13- to 30-fold in Japanese quail). Among Species, the rank order of sensitivity (most to least) to EROD and CYP1A4/CYP1A5 mRNA induction for TCDD and TCDF was chicken > ring-necked pheasant > Japanese quail. In contrast, the three Species were approximately equisensitive to EROD and CYP1A4/CYP1A5 mRNA induction by PeCDF. It has generally been assumed that TCDD is the most potent "dioxin-like compound" (DLC) and that the chicken is the most sensitive Avian Species to CYP1A induction by all DLCs. This study indicates that PeCDF is more potent than TCDD in ring-necked pheasant and Japanese quail hepatocytes and that ring-necked pheasant, Japanese quail, and chicken hepatocytes are equally sensitive to CYP1A induction by PeCDF.
Doug Crump - One of the best experts on this subject based on the ideXlab platform.
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amino acid sequence of the ligand binding domain of the aryl hydrocarbon receptor 1 predicts sensitivity of wild birds to effects of dioxin like compounds
Toxicological Sciences, 2013Co-Authors: Gillian E Manning, Reza Farmahin, Doug Crump, Stephanie P Jones, Mark E Hahn, Lukas J Mundy, Sibel I KarchnerAbstract:The sensitivity of Avian Species to the toxic effects of dioxin-like compounds (DLCs) varies up to 1000-fold among Species, and this variability has been associated with interSpecies differences in aryl hydrocarbon receptor 1 ligand-binding domain (AHR1 LBD) sequence. We previously showed that LD 50 values, based on in ovo exposures to DLCs, were significantly correlated with in vitro EC 50 values obtained with a luciferase reporter gene (LRG) assay that measures AHR1-mediated induction of cytochrome P4501A in COS-7 cells transfected with Avian AHR1 constructs. Those findings suggest that the AHR1 LBD sequence and the LRG assay can be used to predict Avian Species sensitivity to DLCs. In the present study, the AHR1 LBD sequences of 86 Avian Species were studied, and differences at amino acid sites 256, 257, 297, 324, 337, and 380 were identified. Site-directed mutagenesis, the LRG assay, and homology modeling highlighted the importance of each amino acid site in AHR1 sensitivity to 2,3,7,8-tetrachlorodibenzo-p-dioxin and other DLCs. The results of the study revealed that (1) only amino acids at sites 324 and 380 affect the sensitivity of AHR1 expression constructs of the 86 Avian Species to DLCs and (2) in vitro luciferase activity of AHR1 constructs containing only the LBD of the Species of interest is significantly correlated (r 2 = 0.93, p < 0.0001) with in ovo toxicity
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a luciferase reporter gene assay and aryl hydrocarbon receptor 1 genotype predict the ld50 of polychlorinated biphenyls in Avian Species
Toxicology and Applied Pharmacology, 2012Co-Authors: Gillian E Manning, Reza Farmahin, Doug Crump, Stephanie P Jones, Jeff Klein, Alex Konstantinov, Dave Potter, Sean W KennedyAbstract:: Birds differ in sensitivity to the embryotoxic effects of polychlorinated biphenyls (PCBs), which complicates environmental risk assessments for these chemicals. Recent research has shown that the identities of amino acid residues 324 and 380 in the Avian aryl hydrocarbon receptor 1 (AHR1) ligand binding domain (LBD) are primarily responsible for differences in Avian Species sensitivity to selected dibenzo-p-dioxins and furans. A luciferase reporter gene (LRG) assay was developed in our laboratory to measure AHR1-mediated induction of a cytochrome P450 1A5 reporter gene in COS-7 cells transfected with different Avian AHR1 constructs. In the present study, the LRG assay was used to measure the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and PCBs 126, 77, 105 and 118 on luciferase activity in COS-7 cells transfected with AHR1 constructs representative of 86 Avian Species in order to predict their sensitivity to PCB-induced embryolethality and the relative potency of PCBs in these Species. The results of the LRG assay indicate that the identity of amino acid residues 324 and 380 in the AHR1 LBD are the major determinants of Avian Species sensitivity to PCBs. The relative potency of PCBs did not differ greatly among AHR1 constructs. Luciferase activity was significantly correlated with embryolethality data obtained from the literature (R(2)≥0.87, p<0.0001). Thus, the LRG assay in combination with the knowledge of a Species' AHR1 LBD sequence can be used to predict PCB-induced embryolethality in potentially any Avian Species of interest without the use of lethal methods on a large number of individuals.
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a luciferase reporter gene assay and aryl hydrocarbon receptor 1 genotype predict the ld50 of polychlorinated biphenyls in Avian Species
Toxicology and Applied Pharmacology, 2012Co-Authors: Gillian E Manning, Reza Farmahin, Doug Crump, Stephanie P Jones, Jeff Klein, Alex Konstantinov, Dave Potter, Sean W KennedyAbstract:Abstract Birds differ in sensitivity to the embryotoxic effects of polychlorinated biphenyls (PCBs), which complicates environmental risk assessments for these chemicals. Recent research has shown that the identities of amino acid residues 324 and 380 in the Avian aryl hydrocarbon receptor 1 (AHR1) ligand binding domain (LBD) are primarily responsible for differences in Avian Species sensitivity to selected dibenzo-p-dioxins and furans. A luciferase reporter gene (LRG) assay was developed in our laboratory to measure AHR1-mediated induction of a cytochrome P450 1A5 reporter gene in COS-7 cells transfected with different Avian AHR1 constructs. In the present study, the LRG assay was used to measure the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and PCBs 126, 77, 105 and 118 on luciferase activity in COS-7 cells transfected with AHR1 constructs representative of 86 Avian Species in order to predict their sensitivity to PCB-induced embryolethality and the relative potency of PCBs in these Species. The results of the LRG assay indicate that the identity of amino acid residues 324 and 380 in the AHR1 LBD are the major determinants of Avian Species sensitivity to PCBs. The relative potency of PCBs did not differ greatly among AHR1 constructs. Luciferase activity was significantly correlated with embryolethality data obtained from the literature (R2 ≥ 0.87, p
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cytochrome p4501a induction by 2 3 7 8 tetrachlorodibenzo p dioxin and two chlorinated dibenzofurans in primary hepatocyte cultures of three Avian Species
Toxicological Sciences, 2010Co-Authors: Jessica C Herve, John P. Giesy, Doug Crump, Stephanie P Jones, Lukas J Mundy, Matthew J Zwiernik, Steven J Bursian, Paul D Jones, Steve WisemanAbstract:Relative potencies of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), and 2,3,7, 8-tetrachlorodibenzofuran (TCDF) were determined in vitro in primary hepatocyte cultures of chicken (Gallus gallus), ring-necked pheasant (Phasianus colchicus), and Japanese quail (Coturnix japonica) embryos. Concentration-dependent effects on ethoxyresorufin O-deethylase (EROD) activity and expression of cytochrome P4501A4 and cytochrome P4501A5 (CYP1A4 and CYP1A5) messenger RNA (mRNA) were determined in hepatocytes exposed to serial dilutions of TCDD, PeCDF, or TCDF for 24 h. In chicken hepatocytes, the three compounds were equipotent inducers of EROD activity and CYP1A4/CYP1A5 mRNA expression. However, in ring-necked pheasant and Japanese quail hepatocytes, PeCDF was more potent than TCDD (3- to 5-fold in ring-necked pheasant and 13- to 30-fold in Japanese quail). Among Species, the rank order of sensitivity (most to least) to EROD and CYP1A4/CYP1A5 mRNA induction for TCDD and TCDF was chicken > ring-necked pheasant > Japanese quail. In contrast, the three Species were approximately equisensitive to EROD and CYP1A4/CYP1A5 mRNA induction by PeCDF. It has generally been assumed that TCDD is the most potent "dioxin-like compound" (DLC) and that the chicken is the most sensitive Avian Species to CYP1A induction by all DLCs. This study indicates that PeCDF is more potent than TCDD in ring-necked pheasant and Japanese quail hepatocytes and that ring-necked pheasant, Japanese quail, and chicken hepatocytes are equally sensitive to CYP1A induction by PeCDF.
Gillian E Manning - One of the best experts on this subject based on the ideXlab platform.
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amino acid sequence of the ligand binding domain of the aryl hydrocarbon receptor 1 predicts sensitivity of wild birds to effects of dioxin like compounds
Toxicological Sciences, 2013Co-Authors: Gillian E Manning, Reza Farmahin, Doug Crump, Stephanie P Jones, Mark E Hahn, Lukas J Mundy, Sibel I KarchnerAbstract:The sensitivity of Avian Species to the toxic effects of dioxin-like compounds (DLCs) varies up to 1000-fold among Species, and this variability has been associated with interSpecies differences in aryl hydrocarbon receptor 1 ligand-binding domain (AHR1 LBD) sequence. We previously showed that LD 50 values, based on in ovo exposures to DLCs, were significantly correlated with in vitro EC 50 values obtained with a luciferase reporter gene (LRG) assay that measures AHR1-mediated induction of cytochrome P4501A in COS-7 cells transfected with Avian AHR1 constructs. Those findings suggest that the AHR1 LBD sequence and the LRG assay can be used to predict Avian Species sensitivity to DLCs. In the present study, the AHR1 LBD sequences of 86 Avian Species were studied, and differences at amino acid sites 256, 257, 297, 324, 337, and 380 were identified. Site-directed mutagenesis, the LRG assay, and homology modeling highlighted the importance of each amino acid site in AHR1 sensitivity to 2,3,7,8-tetrachlorodibenzo-p-dioxin and other DLCs. The results of the study revealed that (1) only amino acids at sites 324 and 380 affect the sensitivity of AHR1 expression constructs of the 86 Avian Species to DLCs and (2) in vitro luciferase activity of AHR1 constructs containing only the LBD of the Species of interest is significantly correlated (r 2 = 0.93, p < 0.0001) with in ovo toxicity
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a luciferase reporter gene assay and aryl hydrocarbon receptor 1 genotype predict the ld50 of polychlorinated biphenyls in Avian Species
Toxicology and Applied Pharmacology, 2012Co-Authors: Gillian E Manning, Reza Farmahin, Doug Crump, Stephanie P Jones, Jeff Klein, Alex Konstantinov, Dave Potter, Sean W KennedyAbstract:: Birds differ in sensitivity to the embryotoxic effects of polychlorinated biphenyls (PCBs), which complicates environmental risk assessments for these chemicals. Recent research has shown that the identities of amino acid residues 324 and 380 in the Avian aryl hydrocarbon receptor 1 (AHR1) ligand binding domain (LBD) are primarily responsible for differences in Avian Species sensitivity to selected dibenzo-p-dioxins and furans. A luciferase reporter gene (LRG) assay was developed in our laboratory to measure AHR1-mediated induction of a cytochrome P450 1A5 reporter gene in COS-7 cells transfected with different Avian AHR1 constructs. In the present study, the LRG assay was used to measure the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and PCBs 126, 77, 105 and 118 on luciferase activity in COS-7 cells transfected with AHR1 constructs representative of 86 Avian Species in order to predict their sensitivity to PCB-induced embryolethality and the relative potency of PCBs in these Species. The results of the LRG assay indicate that the identity of amino acid residues 324 and 380 in the AHR1 LBD are the major determinants of Avian Species sensitivity to PCBs. The relative potency of PCBs did not differ greatly among AHR1 constructs. Luciferase activity was significantly correlated with embryolethality data obtained from the literature (R(2)≥0.87, p<0.0001). Thus, the LRG assay in combination with the knowledge of a Species' AHR1 LBD sequence can be used to predict PCB-induced embryolethality in potentially any Avian Species of interest without the use of lethal methods on a large number of individuals.
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a luciferase reporter gene assay and aryl hydrocarbon receptor 1 genotype predict the ld50 of polychlorinated biphenyls in Avian Species
Toxicology and Applied Pharmacology, 2012Co-Authors: Gillian E Manning, Reza Farmahin, Doug Crump, Stephanie P Jones, Jeff Klein, Alex Konstantinov, Dave Potter, Sean W KennedyAbstract:Abstract Birds differ in sensitivity to the embryotoxic effects of polychlorinated biphenyls (PCBs), which complicates environmental risk assessments for these chemicals. Recent research has shown that the identities of amino acid residues 324 and 380 in the Avian aryl hydrocarbon receptor 1 (AHR1) ligand binding domain (LBD) are primarily responsible for differences in Avian Species sensitivity to selected dibenzo-p-dioxins and furans. A luciferase reporter gene (LRG) assay was developed in our laboratory to measure AHR1-mediated induction of a cytochrome P450 1A5 reporter gene in COS-7 cells transfected with different Avian AHR1 constructs. In the present study, the LRG assay was used to measure the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and PCBs 126, 77, 105 and 118 on luciferase activity in COS-7 cells transfected with AHR1 constructs representative of 86 Avian Species in order to predict their sensitivity to PCB-induced embryolethality and the relative potency of PCBs in these Species. The results of the LRG assay indicate that the identity of amino acid residues 324 and 380 in the AHR1 LBD are the major determinants of Avian Species sensitivity to PCBs. The relative potency of PCBs did not differ greatly among AHR1 constructs. Luciferase activity was significantly correlated with embryolethality data obtained from the literature (R2 ≥ 0.87, p
