| Grant number: | 11/52061-8 |
| Support Opportunities: | Program for Research on Bioenergy (BIOEN) - Regular Program Grants |
| Start date: | June 01, 2012 |
| End date: | May 31, 2014 |
| Field of knowledge: | Biological Sciences - Biochemistry - Metabolism and Bioenergetics |
| Principal Investigator: | Eduardo Alves de Almeida |
| Grantee: | Eduardo Alves de Almeida |
| Host Institution: | Instituto de Biociências, Letras e Ciências Exatas (IBILCE). Universidade Estadual Paulista (UNESP). Campus de São José do Rio Preto. São José do Rio Preto , SP, Brazil |
| City of the host institution: | São José do Rio Preto |
Abstract
This project aims to elucidate some mechanisms of toxicity of diuron and three of its main metabolites (dichlorophenylurea, DCPU, dichlorophenylmethylurea, DCPMU and dichloroaniline, DCA), singly or in mixtures of diuron with its metabolites, and diuron and its metabolites with two environmentally relevant alkylphenois, nonylphenol (NP) and octylphenol (OP). Experiments will be performed by exposing Nile tilapias for 2 and 7 days to single compounds and in combination, and then a series of biochemical biomarkers will be evaluated: biotransformation enzymes (cytochrome P450 isoform 1A, glutathione S-transferase), antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, glucose 6-phosphate dehydrogenase, glutathione reductase), levels of lipid peroxidation, reduced glutathione levels, quantification of micronuclei, and comet assays. To evaluate the estrogenic effect of diuron and its metabolites in combination with alkylphenois, it will be evaluated levels of testosterone, 11-ketotestosterone, 17 b-estradiol and vitellogenin in the plasma of fish, and activity of 17 b-hydroxy-steroid dehydrogenase and aromatase in the liver, in collaboration with Prof. Dr. Daniel Schlenk, from University of California (USA). Moreover, studies of in vitro and in vivo metabolism of the compounds by the fish will be carried out by measuring the presence of the compounds and their metabolites in plasma and bile of fish by U/HPLC coupled to a mass spectrometer, and incubation experiments of compounds with microsomal and cytosolic protein extracts and quantification of product formation by U/HPLC coupled to mass spectrometry. Similarly, the concentration of the compounds used in aquariums should be monitored. Studies of the inhibitory potential of compounds in the proposed enzymes will also be performed in vitro by incubating protein extracts of fish with increasing concentrations of the compounds and subsequent measurement of enzyme activity. We believe this project will bring a lot of new information regarding the mechanisms of action of diuron and alkylphenois in fish. In addition, this project will be also important in the establishment and consolidation of an international collaboration. (AU)
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