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Suzanne Trudeau - One of the best experts on this subject based on the ideXlab platform.

  • hepatic erod activity is not a useful biomarker of polychlorinated biphenyl exposure in the adult herring gull larus argentatus
    Ecotoxicology, 2003
    Co-Authors: Sean W. Kennedy, Glen A Fox, Stephanie P Jones, Suzanne Trudeau
    Abstract:

    Liver concentrations of polychlorinated biphenyls (PCBs) and chicken embryo hepatocyte (CEH) bioassay-derived 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQs) were measured in livers of adult herring gulls (Larus argentatus) collected from several locations on the Great Lakes and two reference sites. Total PCB concentrations (sum of 42 congeners) and TCDD-EQ concentrations were compared with hepatic Ethoxyresorufin-O-Deethylase (EROD) activity, mEthoxyresorufin-O-Deethylase (MROD) activity and immunodetectable cytochrome P4501A (CYP1A) protein concentration. EROD and MROD activity were not significantly correlated with total PCB concentration or TCDD-EQ concentration in liver tissue. CYP1A protein concentration was significantly correlated with total PCB concentration, but the linear relationship had little predictive power. We conclude that EROD is not a useful biomarker of PCB exposure in the adult herring gull.

  • reproductive success and biochemical effects in tree swallows tachycineta bicolor exposed to chlorinated hydrocarbon contaminants in wetlands of the great lakes and st lawrence river basin usa and canada
    Environmental Toxicology and Chemistry, 1999
    Co-Authors: Christine A Bishop, Nancy A. Mahony, Suzanne Trudeau, Karen E Pettit
    Abstract:

    Reproduction and biochemical indicators (vitamin A, Ethoxyresorufin-O-Deethylase [EROD], highly carboxylated porphyrins) of contaminant effects, and concentrations of organochlorine residues were measured in tree swallows from wetlands within the watersheds of the Great Lakes and the St. Lawrence River, USA and Canada. To assess the vitamin A sources in the tree swallow diets, insects were collected, by ligature, from nestlings at four of these sites. Diet samples were analyzed for retinol and α- and β-carotene. Marked differences were found in chlorinated hydrocarbon residues in eggs and nestlings among sites; however, we did not find any significant differences in hatching or fledging success. The maximum polychlorinated biphenyl (PCB) concentration found was 11.1 μg/g in eggs from Akwesasne Reserve, New York, USA, on the St. Lawrence River, whereas the highest p, p′-DDE concentration of 2.57 μg/g was found in eggs from Mud Creek, Ontario, Canada, in the Lake Erie watershed. Concentrations of other organochlorine pesticides and chlorobenzenes were low and not variable among sites. Significant differences in hepatic EROD activity, retinol and retinyl palmitate, and uroporphyrin in nestling birds existed among sites. Ethoxyresorufin O-deethylase activity was highest and retinol and retinyl palmitate were lowest at Cornwall Island, Ontario, Canada, in the St. Lawrence River, whereas porphyrins were highest at Toronto and Hamilton harbors, Ontario, Canada, in Lake Ontario. Ethoxyresorufin O-deethylase induction was significantly and negatively correlated with nestling hepatic retinol concentrations, whereas uroporphyrin concentrations were positively correlated with PCB congener 118 in nestlings. In contrast, few differences occurred in vitamin A concentrations in diet samples among sites. Together, these findings suggest that depressed hepatic vitamin A and elevated highly carboxylated porphyrin concentrations are strongly associated with sites with the highest organochlorine exposure in tree swallows.

Ximei Liang - One of the best experts on this subject based on the ideXlab platform.

  • effects of norfloxacin on hepatic genes expression of p450 isoforms cyp1a and cyp3a gst and p glycoprotein p gp in swordtail fish xiphophorus helleri
    Ecotoxicology, 2015
    Co-Authors: Ximei Liang, Xiangping Nie, Lan Wang, Yufeng Yang, Fang Wang
    Abstract:

    The presence of antibiotics including norfloxacin in the aquatic environment may cause adverse effects in non-target organisms. But the toxic mechanisms of fluoroquinolone to fish species are still not completely elucidated. Thus, it is essential to investigate the response of fish to the exposure of fluoroquinolone at molecular or cellular level for better and earlier prediction of these environmental pollutants toxicity. The sub-chronic toxic effects of norfloxacin (NOR) on swordtail fish (Xiphophoru s helleri) were investigated by measuring mRNA expression of cytochrome P450 1A (CYP1A), cytochrome P450 3A (CYP3A), glutathione S-transferase (GST) and P-glycoprotein (P-gp) and their corresponding enzyme activities (including ethoxyresorufin O-deethylase, erythromycin N-demethylase and GST. Results showed that NOR significantly affected the expression of CYP1A, CYP3A, GST and P-gp genes in swordtails. The gene expressions were more responsive to NOR exposure than their corresponding enzyme activities. Moreover, sexual differences were found in gene expression and enzyme activities of swordtails exposed to NOR. Females displayed more dramatic changes than males. The study further demonstrated that the combined biochemical and molecular parameters were considered as useful biomarkers to improve our understanding of potential ecotoxicological risks of NOR exposure to aquatic organisms.

  • Assessment of toxic effects of triclosan on the swordtail fish (Xiphophorus helleri) by a multi-biomarker approach
    Chemosphere, 2012
    Co-Authors: Ximei Liang, Xiangping Nie, Guang-guo Ying
    Abstract:

    Abstract The toxic effects of triclosan (TCS) on the swordtail fish ( Xiphophorus helleri ) were assessed based on various biomarkers including enzymatic activities of ethoxyresorufin O-deethylase (EROD), erythromycin N-demethylase (ERND) and glutathione-s-transferase (GST) and mRNA expression levels of CYP1A, CYP3A, glutathione S-transferase (GST) and P-glycoprotein (P-gp). The acute toxicity test showed the LC 50 value of 1.47 mg L −1 for TCS. The mRNA expressions of CYP1A, CYP3A, GST and P-gp showed dose–effect relationships in female swordtail fish when exposed to TCS, These mRNA expression levels were found more sensitive to TCS exposure than the enzymatic activities of EROD, ERND and GST do. In addition, the male fish displayed higher gene expression levels and more dramatic changes in enzyme activities than the females did. Our data further demonstrated that TCS was a typical inducer to Phase I and Phase II metabolism enzymes and genes, suggesting it is a potential ecotoxicological risk to aquatic ecosystems.

Pingkun Chan - One of the best experts on this subject based on the ideXlab platform.

  • effects of amitraz on cytochrome p450 dependent monooxygenases and estrogenic activity in mcf 7 human breast cancer cells and immature female rats
    Food and Chemical Toxicology, 2004
    Co-Authors: Tzuuhuei Ueng, Chiachi Hung, Huiwu Wang, Pingkun Chan
    Abstract:

    Abstract This study investigated the ability of amitraz, a formamidine insecticide, to induce cytochrome P450-dependent monooxygenases and to disrupt estrogenic activity in human breast cancer MCF-7 cells and immature female rats. In MCF-7 cells, treatment with 10 μM amitraz for 24 h increased 7-ethoxyresorufin O-deethylase activity in cell homogenate. Treatment of MCF-7 cells with 1 and 10 μM amitraz for 3 h replaced previously bound [3H]17β-estradiol (E2) from estrogen receptors. Treatment with 0.1 and 1 μM amitraz for 2 days inhibited [3H]thymidine incorporation into the DNA of MCF-7 cells while the inhibition was blocked in cells co-treated with 1 nM E2 and amitraz. In immature female rats, treatment with 50 mg/kg amitraz intraperitoneally for 3 days increased cytochrome P450 content, 7-ethoxyresorufin, methoxyresorufin and pentoxyresorufin O-dealkylases, and benzo[a]pyrene hydroxylase activities in liver microsomes. The results of immunoblot analysis revealed that amitraz induced liver microsomal CYP1A1/2, 2B1/2B2, and 3A proteins. Treatment with 10 and 25 mg/kg amitraz for 3 days dose-dependently decreased uterine weight and peroxidase activity in immature female rats while the decreases were blocked in rats co-treated with 10 μg/kg E2 and 10 or 25 mg/kg amitraz. These in vitro and in vivo findings suggest that amitraz induces multiple forms of P450 and exerts weak antiestrogenic activity.

Jiayin Dai - One of the best experts on this subject based on the ideXlab platform.

  • effects of pentachlorophenol on the quail coturnix japonica liver detoxification pathway
    Chemosphere, 2017
    Co-Authors: Peng Jiang, Jianshe Wang, Nan Sheng, Dongbing Wei, Jiayin Dai
    Abstract:

    Pentachlorophenol (PCP), an extensively used pesticide and biocide, is of critical environmental concern due to its toxicity and recalcitrance to degradation. In this study, the effect of PCP on induction of transcription factors, cytochrome P450 (CYP450) genes, and the antioxidative enzyme system were investigated in the quail liver. A total of 60 (4- to 6-week-old) male quails (Coturnix japonica) were administered 0, 0.05, 0.5, and 5 mg/kg/d PCP orally for 42 d. Following exposure, both absolute and relative liver weights were significantly lower than those of the control. Using gas chromatography-mass spectrometry, PCP accumulation was, from highest to lowest, kidney > liver > muscle for all exposure groups. The expressions of CYP1A5, CYP1B1, CYP2C18, nuclear translocator 1 (ARNT1), and aryl hydrocarbon receptor 1 (AHR1) were induced after PCP treatment, and increases were found in the activities of hepatic superoxide dismutase (SOD) and catalase (CAT), and the content of hepatic malondialdehyde (MDA). In addition, exposure to PCP induced an increase in liver 8-hydroxydeoxyguanosine (8-OHdG) and significantly elevated ethoxyresorufin O-deethylase (EROD), methoxyresorufin O-demethylase (MROD), and 7-ethoxycoumarin-O-deethylase (ECOD) activity, but decreased that of glutathione peroxidase (GSH-Px), benzyloxyresorufin O-debenzylase (BROD), pentoxyresorufin O-depentylase (PROD), and erythromycin N-demethylase (END). No significant responses were observed for benzyloxy-trifluoromethyl-coumarin (BFC). The protein level of liver nuclear factor κB (NF-κB) was higher, whereas that of nuclear factor E2-related factor 2 (Nrf2) was lower for exposed quail. These results suggest that PCP affects quail oxidative stress by modulating CYP450 enzymes and nuclear transcription factors.

Sean W. Kennedy - One of the best experts on this subject based on the ideXlab platform.