Search results for "CYP1A1"
showing 10 items of 42 documents
Do historical sediments of pulp and paper industry contribute to the exposure of fish caged in receiving waters?
2011
Field experiments were conducted in early summer 2004 by caging brown trout (Salmo trutta m. lacustris) in Southern Lake Saimaa (SE Finland) for 10 days. Cages were positioned into two depths at four distances (5 to 17 km) from the pulp and paper mill; one set with direct contact to the sediment and other locating at the three meters' depth from the water surface. Resin acids were measured from sediment, water, and fish bile. Possible toxicities were investigated by measuring liver EROD-activity, HSP70-protein, and gene expression profiles by microarray. The concentration of resin acids in the sediment showed clear gradient along the distance from the mill, and their concentrations in water…
The capacity of liver microsomes to form benzo[a]pyrene-diolepoxide-DNA adducts and induction of cytochrome P450 1A in feral fish exposed to pulp mil…
1996
An investigation was made of cytochrome P4501A (CYP1A) induction, determined by the activity of EROD (7-ethoxyresorufin O-deethylase), and formation of benzo[a]pyrene-diolepoxide-DNA (BPDE-DNA) adducts, measured by synchronous fluorescence spectrophotometry, in liver microsomes of perch (Perca fluviatilis), bream (Abramis brama), and roach (Rutilus rutilus). Fish were collected from the southern part of Lake Saimaa (Finland), an area polluted by effluents from the pulp and paper industry. In addition, two conjugation enzymes (UDP-glucuronosyltransferase and glutathione S-transferase) were determined. Overall, when compared to an upstream reference, EROD activity was higher in fish at waters…
Biological effects of high molecular weight lignin derivatives
2010
Abstract A number of high molecular weight (HMW) lignin derivatives possessing varied chemical properties were screened for their biological effects in order to obtain more information on the possible structural features of HMW lignin-related effects. The studied compounds were both commercial and in-house extracted lignin derivatives. Bioassays used include reverse electron transport (RET), Vibrio fischeri, Daphnia magna , and juvenile rainbow trout ( Oncorhynchus mykiss) hepatocytes. The studied lignin derivatives inhibited the in vitro systems and luminescence of V. fischeri bacteria to some extent–daphnids were not affected. It seems that, at least in the RET assay, certain pH-dependent…
Effects of Acute Handling Stress on Whitefish Coregonus lavaretus After Prolonged Exposure to Biologically Treated and Untreated Bleached Kraft Mill …
2000
Exposure of fish to water of impaired quality has been shown to disrupt the function of the hypothalamo-pituitary-interrenal (HPI) axis and alter the interpretation of data from field studies due to the varying effects of handling and delayed sampling on exposed and reference animals. In the present study, juvenile whitefish, Coregonus lavaretus, were exposed for 6 weeks to diluted (4-8%) untreated and biologically treated bleached kraft mill effluent (BKME) and their response to acute handling was investigated. Liver microsomal EROD activity and glycogen phosphorylase (GPase) activity, in addition to gill Na+-K+-ATPase activity, and blood hemoglobin and hematocrit levels were increased in …
Epoxidation of benzo[a]pyrene-7,8-dihydrodiol by human CYP1A1 in reconstituted membranes. Effects of charge and nonbilayer phase propensity of the me…
2002
Human cytochrome P4501A1 (CYP1A1) is one of the key enzymes in the bioactivation of environmental pollutants such as benzo[a]pyrene (B[a]P) and other polycyclic aromatic hydrocarbons. To evaluate the effect of membrane properties and distinct phospholipids on the activity of human CYP1A1 purified insect cell-expressed human CYP1A1 and of human NADPH-P450 reductase were reconstituted into phospholipid vesicle membranes. Conversion rates of up to 36 pmol x min(-1) x pmol(-1) CYP1A1 of the enantiomeric promutagens (-)- and (+)-trans-7,8-dihydroxy-7,8-dihydro-B[a]P (7,8-diol) to the genotoxic diolepoxides were achieved. The highest rates were obtained when negatively charged lipids such as phos…
Effects of garlic powders with varying alliin contents on hepatic drug metabolizing enzymes in rats
2003
International audience; The anticarcinogenic effect of garlic has been demonstrated in both epidemiologic and experimental studies. In this study, possible mechanisms involved in the anticarcinogenic effect of garlic consumption were assessed by determining its capacity to alter drug metabolizing enzymes, in relation with its alliin content. Rats were fed a diet for 2 weeks containing 5% garlic powders produced from bulbs grown on soils with different levels of sulfate fertilization and therefore containing differing amounts of alliin. Activities of several hepatic enzymes, which are important in carcinogen metabolism such cytochromes P450 (CYP) and phase II enzymes, were determined. Garlic…
More accuracy to the EROD measurements—The resorufin fluorescence differs between species and individuals
2012
Ethoxyresorufin-O-deethylase (EROD) activity is a biomarker of exposure to planar aromatic hydrocarbons, and it is often measured from the S9 fraction. The effect of the liver S9 fraction of seven boreal freshwater fish species on the fluorescence of resorufin was studied. The S9 fractions diminished resorufin fluorescence by 40–80%, and there were large differences between species. Thus, using a resorufin standard curve without the S9 fraction leads to a large underestimation of the EROD activity. Therefore a microwell plate EROD method was developed that takes into account the effect of each sample on resorufin fluorescence. At least two mechanisms were involved in the decrease of the flu…
Metabolic activation of dibenzo[a,l]pyrene by human cytochrome P450 1A1 and P450 1B1 expressed in V79 Chinese hamster cells.
1999
Metabolic activation of the strongly carcinogenic polycyclic aromatic hydrocarbon (PAH) dibenzo[a,l]pyrene (DB[a,l]P) and its trans-8,9-dihydrodiol (trans-8,9-diol) catalyzed by human cytochromes P450 (P450) 1A1 and 1B1 was investigated. DNA binding of DB[a,l]P in mammalian cell lines has previously been shown to be preferentially mediated by fjord region DB[a,l]P-11,12-dihydrodiol 13,14-epoxides (DB[a,l]PDE). In order to elucidate different capabilities of both P450 enzymes for metabolic activation of DB[a, l]P V79 Chinese hamster cells, stably expressing human P450s 1A1 or 1B1 have been exposed to the parent PAH or its racemic trans-8, 9-diol. For this purpose, synthesis and spectroscopic…
Targeting the aryl hydrocarbon receptor with a novel set of triarylmethanes
2020
International audience; The aryl hydrocarbon receptor (AhR) is a chemical sensor upregulating the transcription of responsive genes associated with endocrine homeostasis, oxidative balance and diverse metabolic, immunological and inflammatory processes, which have raised the pharmacological interest on its modulation. Herein, a novel set of 32 unsymmetrical triarylmethane (TAM) class of structures has been synthesized, characterized and their AhR transcriptional activity evaluated using a cell-based assay. Eight of the assayed TAM compounds (14, 15, 18, 19, 21, 22, 25, 28) exhibited AhR agonism but none of them showed antagonist effects. TAMs bearing benzotrifluoride, naphthol or heteroarom…
Tissue bioaccumulation patterns, xenobiotic biotransformation and steroid hormone levels in Atlantic salmon (Salmo salar) fed a diet containing perfl…
2011
In the present study, groups of juvenile Atlantic salmon (Salmo salar) were fed gelatine capsules containing fish-food spiked with PFOA or PFOS (0.2 mg kg(-1) fish) and solvent (methanol). The capsules were given at days 0, 3 and 6. Blood, liver and whole kidney samples were collected prior to exposure (no solvent control), and at days 2, 5, 8 and 14 after exposure (Note: that day 14 after exposure is equal to 7d recovery period). We report on the differences in the tissue bioaccumulation patterns of PFOS and PFOA, in addition to tissue and compound differences in modulation pattern of biotransformation enzyme genes. We observed that the level of PFOS and PFOA increased in the blood, liver …