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EVALUATION OF TOXICITY, GENOTOXICITY AND MUTAGENICITY OF THE FIPRONIL AND THIAMETHOXAM INSECTICIDES, USING CYTOLOGICAL TECHNIQUES IN Allium cepa TEST SYSTEM, AND GENE EXPRESSION AND OXIDATIVE STRESS ASSAYS IN MAMMALIAN CELL CULTURES.

Grant number: 11/02511-7
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): October 01, 2011
Effective date (End): January 31, 2014
Field of knowledge:Biological Sciences - Genetics - Mutagenesis
Principal Investigator:Maria Aparecida Marin Morales
Grantee:Bruna de Campos Ventura Camargo
Home Institution: Instituto de Biociências (IB). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil

Abstract

Agriculture is one of the sectors that promotes environmental contamination by toxic substances entering the environment. Among them, one can mention two important groups of insecticides, neonicotinoids, such as thiamethoxam, and phenylpyrazole, such as fipronil. Biological toxicity tests, performed with different methodos and test systems, are indispensable for evaluating the responses of organisms to environmental pollution and is therefore suitable for evaluating the genotoxic effects of chemicals in general. Tests with cell cultures bring reliable information and insightful, in short periods. The CHO and HTC cell lines will be cultured and exposed to the different concentrations of thiamethoxam and fipronil, in order to assess whether these substances have cytotoxic effects (MTT test) and genotoxic (tests of gene expression: cDNA microarrays and PCR real time) tests in these organisms. With these same cells, tests to evaluate the antioxidant potential of insecticides (test of oxidative stress) will also be performed. Allium cepa is also considered an efficient body standard for mutagenicity tests. Seeds of A. cepa will be submitted to germination in different concentrations of thiamethoxam to evaluate their possible cytotoxic effects (analysis of mitotic index and cell death), genotoxic and mutagenic (analysis of chromosomal aberrations in meristematic cells, and micronuclei in meristematic cells and F1) before and after periods of recovery. The widespread use of fipronil and thiamethoxam in Brazilian agriculture and the dangers they cause in the exposed biota, this study aims to determine the genotoxicity and the mechanisms of action of these compounds, using methods of gene expression and oxidative stress in mammal cells, as well as testing for chromosomal aberrations and micronuclei in A. cepa. It is important to consider that this project will allow the deployment, at the Laboratory of Mutagenesis, UNESP - Rio Claro, of 2 new techniques that emerge in environmental mutagenesis: PCR real-time and cDNA microarrays to assess the genotoxic potential of insecticides in mammal cells. This will be possible by the partnership established between the supervisor of the project with the Laboratory of Genetic Toxicology UEL - Londrina, and the Institute of Environmental Assessment y Estudios del Agua - IDAEA - Spain.