Detalhes bibliográficos
Ano de defesa: |
2013 |
Autor(a) principal: |
Steckling, Bruna
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Orientador(a): |
Pileggi, Marcos
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Banca de defesa: |
Não Informado pela instituição |
Tipo de documento: |
Dissertação
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Tipo de acesso: |
Acesso aberto |
Idioma: |
por |
Instituição de defesa: |
UNIVERSIDADE ESTADUAL DE PONTA GROSSA
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Programa de Pós-Graduação: |
Programa de Pós-Graduação em Ciências Biológicas
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Departamento: |
Biologia Evolutiva
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País: |
BR
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Palavras-chave em Português: |
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Palavras-chave em Inglês: |
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Área do conhecimento CNPq: |
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Link de acesso: |
http://tede2.uepg.br/jspui/handle/prefix/973
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Resumo: |
Agrochemicals have become necessary to improve crops yields and provide the increasing demand for foods. Nevertheless, pesticides can persist in the environment and be harmful to non target organisms. Mesotrione, the active ingredient of Callisto, is a selective herbicide recommended for pre and post-emergent weed control in corn culture, with high leaching potential, and it has the ability to inhibit the activity of HPPD enzyme, interfering with the synthesis of carotenoids in target plants. The aim of this work was to evaluate the strategies used by the strain Bacillus megaterium Mes13 to avoid toxic effects of Callisto and its active substance, mesotrione, by analyzing the differential expression of antioxidative enzymes, mesotrione degradation, and changes in membrane structure. There were no specific responses from isozymes to herbicides. Catalase activity at Callisto treatment was lower than control, suggestingother mechanisms affecting cellular defense. Lipid peroxidation (MDA), which depends on saturation degree of membrane fatty acids, was lower at Callisto treatment, and changes in bacterial membrane were observed at Callisto treatment, probably protecting membrane against lipid peroxidation. Mesotrione was used neither as C nor N source for growing of Bacillus megaterium, although degradation of mesotrione was higher at minimal medium with no N source, suggesting that herbicide degradation occurs as a cometabolism. Probably the membrane modifications and mesotrione degradation made this bacteria able to tolerate the herbicides at experimental conditions. |