Some effects of the fungicide propiconazole on cytochrome P450 and glutathione S-transferase in brown trout (Salmo trutta) (original) (raw)
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In this study, the toxic effects of PCZ, a triazole fungicide present in aquatic environment, were studied in rainbow trout, Oncorhynchus mykiss, by an acute toxicity test. Compared to the control group, fish exposed to PCZ (96-h-LC50 , 5.04 mg/l) showed significantly higher (P < 0.05) plasma NH 3 and GLU concentration and the activities of plasma enzymes including CK, ALT, AST, LDH, but the TP content was not significantly different (P > 0.05). The oxidative stress indices (levels of LPO and CP) of brain and muscle in the experimental group were higher compared to the control group, especially for a significant change (P < 0.05) in the brain. SOD, CAT, GPx and GR activity in the brain of experimental groups was significantly lower (P < 0.05), however, an opposite tendency was found out in muscle. In addition, there are significant correlations between TBARS and CAT, TBARS and GPx, CP, and CAT, GR, and GPx in the fish brain. Thus, PCZ exposure changed the oxidative stress indices and plasma characteristics, and these changes may be used as potential bioindicators of the exposure and effect of PCZ in the controlled experiment. The use in monitoring of PCZ exposure under natural field conditions is possible, but it needs further investigations.
Agricultural Science Digest - A Research Journal
Tricyclazole, a systemic fungicide is recommended to treat of diseases in irrigated rice. Channa punctatus (Bloch) is a freshwater fish also found in paddy fields. This maiden study was designed to evaluate acute toxicity of tricyclazole and its responses of certain biomarker enzymes in Channa punctatus. By regression analysis method, 24, 48, 72 and 96hr-LC50 dose of tricyclazole was calculated 54.30, 36.76, 32.63 and 25.06 mg l-1 respectively. The range of LC50 dose indicates highly toxic nature of tricyclaozole. Fish were then exposed to 0.25 and 1.25 mg l-1 sublethal dose of tricyclazole for short term (24, 48 and 96 hours) and long term (15, 30 and 45 days) exposure and the alterations of enzyme activities were determined. Alkaline phosphatase activities exposed to 0.25 mg l-1 were increased insignificantly (p>0.05) after 24 hours but increased significantly (p less than 0.05) to 0.25 and 1.25 mg l-1 tricyclazole at all other treatments. Alanine transaminase and aspartate tra...
Aquatic Toxicology, 2008
This study focuses on effects of two classes of xenobiotics, azole fungicides and xenoestrogens, both of which have been detected in the aquatic environment. We hypothesize that azoles and estrogenic compounds are metabolized by cytochrome P450 (CYP) enzymes, and in particular CYP1A and CYP3A, to more readily excreted metabolites. We exposed rainbow trout (Oncorhynchus mykiss) to two different pharmaceutical representatives of theses two classes, such as the imidazole ketoconazole and the synthetic estrogen analogue, 17␣-ethynylestradiol (EE 2 ). Juvenile rainbow trout were i.p. injected with a single low dose of EE 2 (2.5 g/kg), alone or in combination with ketoconazole (100 mg/kg). Hepatic microsomal CYP1A and CYP3A protein expressions were analyzed in Western blots using polyclonal antibodies (PAb) and enhanced cheminoluminescence. CYP1A activities were analyzed using the ethoxyresorufin-O-deethylase (EROD) assay and CYP3A activities were analyzed using the benzyloxy-4-[trifluoromethyl]-coumarin-O-debenzyloxylase (BFCOD) assay. Plasma vitellogenin (vtg) and sex steroid hormones (i.e. 17-estradiol, testosterone and 11-keto-testosterone) were analyzed using commercially available ELISA-kits. The vtg mRNA expression was analyzed using quantitative (Q)-PCR. The dose of EE 2 selected had little or no effect on the estrogen receptor (ER) mediated vtg induction. However, in combination with ketoconazole this threshold-dose of EE 2 resulted in significantly elevated plasma vtg levels, 6 days post injection. Exposure to ketoconazole resulted in up to nine-fold induction of CYP1A after 3 days. However, this nine-fold induction was not reflected on the CYP1A catalytic activity, where exposure to ketoconazole resulted only in a two-fold increase in activity. Ketoconazole increased CYP3A protein levels 1.5-fold and decreased BFCOD activities by 80% at days 3 and 6. Treatment with ketoconazole and EE 2 alone and in combination had no significant effect on sex steroid hormones, compared to vehicle-treated fish. This study demonstrates that exposure to ketoconazole compromises the function of key enzymes involved in metabolic clearance of xenobiotics and steroids, and increases the sensitivity to EE 2 exposure in juvenile rainbow trout.
Aquatic Toxicology, 2008
This study focuses on effects of two classes of xenobiotics, azole fungicides and xenoestrogens, both of which have been detected in the aquatic environment. We hypothesize that azoles and estrogenic compounds are metabolized by cytochrome P450 (CYP) enzymes, and in particular CYP1A and CYP3A, to more readily excreted metabolites. We exposed rainbow trout (Oncorhynchus mykiss) to two different pharmaceutical representatives of theses two classes, such as the imidazole ketoconazole and the synthetic estrogen analogue, 17␣-ethynylestradiol (EE 2 ). Juvenile rainbow trout were i.p. injected with a single low dose of EE 2 (2.5 g/kg), alone or in combination with ketoconazole (100 mg/kg). Hepatic microsomal CYP1A and CYP3A protein expressions were analyzed in Western blots using polyclonal antibodies (PAb) and enhanced cheminoluminescence. CYP1A activities were analyzed using the ethoxyresorufin-O-deethylase (EROD) assay and CYP3A activities were analyzed using the benzyloxy-4-[trifluoromethyl]-coumarin-O-debenzyloxylase (BFCOD) assay. Plasma vitellogenin (vtg) and sex steroid hormones (i.e. 17-estradiol, testosterone and 11-keto-testosterone) were analyzed using commercially available ELISA-kits. The vtg mRNA expression was analyzed using quantitative (Q)-PCR. The dose of EE 2 selected had little or no effect on the estrogen receptor (ER) mediated vtg induction. However, in combination with ketoconazole this threshold-dose of EE 2 resulted in significantly elevated plasma vtg levels, 6 days post injection. Exposure to ketoconazole resulted in up to nine-fold induction of CYP1A after 3 days. However, this nine-fold induction was not reflected on the CYP1A catalytic activity, where exposure to ketoconazole resulted only in a two-fold increase in activity. Ketoconazole increased CYP3A protein levels 1.5-fold and decreased BFCOD activities by 80% at days 3 and 6. Treatment with ketoconazole and EE 2 alone and in combination had no significant effect on sex steroid hormones, compared to vehicle-treated fish. This study demonstrates that exposure to ketoconazole compromises the function of key enzymes involved in metabolic clearance of xenobiotics and steroids, and increases the sensitivity to EE 2 exposure in juvenile rainbow trout.
International Journal of Fisheries and Aquatic Studies, 2019
This maiden study was designed to evaluate acute toxicity of tricyclazole and its responses on certain biomarker in a freshwater fish Channa punctatus (Bloch). By Reed-Muench method, mean 96hr-LC50 dose of tricyclazole for this fish was calculated 25.0 mg l. The LC50 dose indicates highly toxic nature of tricyclaozole. Fish were then treated to 0.25 and 1.25 mg l sublethal dose of tricyclazole for short term long term exposure and the alterations in activities of glucose, protein, urea and cholesterol were determined in serum. Levels of glucose, urea and cholesterol in fish exposed to tricyclazole increased significantly (p<0.05) at all durations of short-term and long-term exposure. Conversely, protein decreased significantly (p<0.05) in response to tricyclazole at both the concentration and all exposure periods. Therefore, exposure to tricyclazole at sub-lethal concentrations induces severe serum biochemical alterations in Channa punctatus that may potentially disrupt their ...
The cytochrome P-450 system in fish, aquatic toxicology and environmental monitoring
Aquatic Toxicology, 1992
Aquatic toxicology has been defined as the qualitative and quantitative study of adverse or toxic effects of chemicals and other anthropogenic materials on aquatic organisms. The subject also includes the study of transport, distribution, transformation and ultimate fate of chemicals in the aquatic environment. Within this multidisciplinary field of science, studies of the biochemistry and function of biotransformation enzymes in aquatic organisms hold a central role. Metabolism or biotransformation through the phase 1 (cytochrome P-450 monooxygenase enzymes) and phase 11 (conjugating enzymes) pathway is a requisite for detoxification and excretion of lipophilic chemicals. In addition, such a transformation is also responsible for the activation of foreign chemicals to the intermediates that ultimately result in toxicity, carcinogenicity, and other adverse effects. The dual role of many of these enzyme systems, being involved in both xenobiotic and endogenous metabolism, furthermore makes interactions between foreign chemicals and physiological processes possible. Lastly, the response of some of these enzyme systems, in particular the cytochrome P-450 I Al subfamily, to organic xenobiotics such as oil hydrocarbons, PCBs, dioxins and dibenzofurens. makes analysis of enzyme levels by catalytic or immunochemical methods a potent way to monitor pollution effects at the molecular level. Several of these aspects will be discussed with special reference to fish.
Aquatic Toxicology, 2006
We have developed a gill-filament based ethoxyresorufin O-deethylase (EROD) assay to be used as a tool to monitor cytochrome P4501A (CYP1A) induction in caged fish. The present study aimed to compare temporal patterns of EROD induction in gills and liver of rainbow trout (Oncorhynchus mykiss) exposed in the laboratory to readily metabolized and persistent CYP1A inducers, i.e. indigo, benzo[a]pyrene (BaP), and 3,3 ,4,4 ,5-pentachlorobiphenyl (PCB#126). Branchial and hepatic EROD activities were examined in fish exposed for 6, 12, or 24 h and in fish exposed for 24 h and then held in clean water for 2 or 14 days. Furthermore, branchial CYP1A protein expression was localized by immunohistochemistry. All compounds strongly induced branchial EROD activity within 6 h. The highest EROD inductions observed for indigo, BaP, and PCB#126 were roughly similar in gills (52-, 76-, and 74-fold), but differed considerably in liver (11-, 78-, and 200-fold). In indigo-and BaP-exposed fish, both hepatic and branchial EROD activities decreased rapidly in clean water. In PCB#126-exposed fish, decreased branchial and increased hepatic EROD activities were observed following transfer to clean water. The substances gave rise to immunostaining for CYP1A at different cellular sites. All inducers increased the CYP1A-immunostaining in the gill filament secondary lamellae, but PCB#126 also induced a pronounced CYP1A immunoreactivity in cells near the basal membrane of the epithelium of the primary lamellae. The observation that the low BaP and indigo concentrations induced EROD activity markedly in the gills but only slightly or not at all in the liver, supports the contention that readily metabolized AhR agonists may escape detection when hepatic EROD activity is used for environmental monitoring. The results show that gill filament EROD activity is a sensitive biomarker both for persistent and readily metabolized AhR agonists in polluted water.
Fish Physiol Biochem, 2000
Liver, kidney, gill and olfactory epithelium cytosolic fractions of rainbow trout (Oncorhynchus mykiss) were examined for glutathione S-transferase (GST) contents. Proteins retained on a glutathione (GSH)-affinity matrix were separated as monomers by reversed-phase HPLC and characterized by immunoblotting, mass spectrometry and partial amino acid sequence. For each organ concerned, a specific pattern of these proteins was determined and appeared similar for liver and kidney on one hand, and for gill and olfactory epithelium on the other hand. It was confirmed that the prominent hepatic GST is a class π enzyme, also constitutively expressed as a major isoform in the four organs studied. Moreover, a class π variant and two new class µ GST subunits were characterized in minor fractions. An unknown protein, which was found major in gills and olfactory epithelium, exhibited some characteristics of class θ GSTs. Occurrence of possible GSH-adduct formation observed on two distinct monomers in specific experimental conditions is discussed. These results and methods were used to investigate the effect of 3,3 ,4,4-tetrachlorobiphenyl (TCB), a polychlorinated biphenyl (PCB), on GST expression in trout liver. From HPLC-profiling, significant co-induction of the major class π and the two minor class µ GST subunits was observed in trout after waterborne exposure to TCB which was followed by a slight increase in 1-chloro-2,4-dinitrobenzene (CDNB) activity. The present work allows qualitative evaluation of the specific detoxification potential of rainbow trout. The use of HPLC-profiling of GSTs as a possible tool for the biomonitoring of polluted aquatic environment is suggested.
Toxicology in Vitro, 2005
A variety of aquatic pollutants are able to induce cytochrome P4501A (CYP1A) in fish by ligand binding to the aryl hydrocarbon receptor (AhR). High-affinity AhR ligands are planar aromatic polycyclic molecules such as the prototypical ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The present work investigates the ability of the imidazole derivative, Prochloraz (PRO), to induce CYP1A. Computational studies on the molecular structure of
Ecotoxicology and Environmental Safety, 2006
Pharmaceutical and personal care products (PPCPs) are found in municipal effluents and represent the major source of contamination for the aquatic environment. A preliminary chemical analysis of wastewater identified several compounds associated with PPCPs, including caffeine, ibuprofen, naproxen, oxytetracycline, novobiocin, carbamazepine, gemfibrozil, bezafibrate, trimethoprim, sulfamethoxazole and sulfapyridine. The purpose of this study was to examine the cytotoxic and oxidative effects of these products and other wastewater-related products (i.e. coprostanol, cotinine, estradiol-17β, nonylphenol and cholesterol) in primary cultures of rainbow trout hepatocytes. The redox activity of various PPCPs in trout (Oncorhynchus mykiss) liver microsomes was investigated in vitro by tracking the rate of oxidation of NADPH and the formation of lipid peroxidation (LPO) after a 60-min incubation period. In addition, primary cultures of rainbow trout hepatocytes were exposed to various drugs identified in the municipal effluent for 48h at 15 o C. Our results show that most PPCPs (83%) accelerated the rate of NADPH oxidation in the presence of microsomes and 72% of them increased LPO in microsomal Ecotoxicol Environ Saf (2006) 64, 329-336 membranes. LPO levels were significantly correlated (R = 0.5; p < 0.05) with the number of functional groups on the molecule's backbone (i.e. number of O, S, N, P/number of C