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Master's Dissertation
DOI
https://doi.org/10.11606/D.11.2008.tde-14032008-153857
Document
Author
Full name
Giselle de Carvalho
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Piracicaba, 2007
Supervisor
Committee
Azevedo, Ricardo Antunes de (President)
Molina, Silvia Maria Guerra
Pileggi, Marcos
Title in Portuguese
Estudo da resposta antioxidativa de linhagens bacterianas na presença do herbicida Acetochlor
Keywords in Portuguese
Bactéria - metabolismo
Estresse oxidativo
Herbicidas - toxidade.
Abstract in Portuguese
Atualmente existe uma grande preocupação com relação aos efeitos a curto e longo prazo que muitos herbicidas podem ter sobre a saúde pública e o meio ambiente. Estes podem causar sérios danos ao metabolismo celular, levando geralmente a inibição do crescimento em microrganismos. Em exposição a herbicidas, esses microrganismos aumentam significativamente a geração de EAOs (Espécies Ativas de Oxigênio), causando estado de estresse oxidativo. O objetivo desse trabalho foi estudar a relação entre o efeito do herbicida acetochlor e a resposta do sistema antioxidante. Três linhagens de Klebsiella oxytoca foram submetidas ao crescimento em meio nutritivo com este herbicida nas concentrações de 0, 62 e 620 mM. O perfil protéico foi avaliado em SDS-PAGE, o qual revelou diferenças de intensidade das bandas, bem como a presença e ausência das mesmas em meio com herbicida. O herbicida causou estresse oxidativo nas três linhagens, o qual foi avaliado através da peroxidação de lipídeos, observado principalmente na concentração de 620 mM. As atividades da Catalase (CAT) e Superóxido Dismutase (SOD) foram altas para as três linhagens na concentração de 62 mM seguida de queda em 620 mM. Para a atividade da Glutationa Redutase (GR) foi observado decréscimo gradativo da atividade com o respectivo aumento da concentração de herbicida para as três linhagens. Porém para a atividade da Glutationa-S-transferase (GST), as três linhagens apresentaram comportamento diferencial para os mesmos tratamentos. O estudo da resposta antioxidativa de microrganismos na presença de xenobióticos são importantes para a compreensão de mecanismos de tolerância, biodegradação bem como para aplicação na biorremediação de ambientes contaminados.
Title in English
Study of the response antioxidative of bacterial strains in the presence of herbicide Acetochlor
Keywords in English
Acetochlor
Antioxidative enzymes.
Bacteria
Herbicide
Oxidative stress
Abstract in English
Currently there is a great concern with respect to short and long term effects that many herbicides may cause on public health and the environment. They may seriously damage the cellular metabolism, generally leading to inhibition of the microbial growth. With the exposure to herbicides, these microorganisms significantly increase the generation of EAOs (Active Oxygen Species), generating a state of oxidative stress. The aim of this work was to study the effect of acetochlor herbicide in the response of antioxidant system. Three strains of the bacteria Klebsiella oxytoca were grown in a nutritional media containing the herbicide in concentrations of 0, 62 and 620 mM. The protein profile was evaluated in SDS-PAGE, which showed differences in the intensity of the bands, as well as the presence and absence in the media with herbicide. The oxidative stress was evaluated through the lipid peroxidation, and herbicide caused stress in all the three strains, mainly at the concentration of 620 mM. The activities of Catalase (CAT) and Superoxide Dismutase (SOD) were higher for the three strains in the concentration of 62 mM followed by a decrease at the concentration of 620 mM. For Glutathione Reductase (GR) it was observed a gradual reduction in its activity with the increase of herbicide concentration for all the three strains. However, in the case of Glutathione-S-transferase (GST) activity, the three strains showed differential behavior for the same treatments. The study of the antioxidative response of microorganisms in the presence of xenobiotics is important for the understanding of tolerance mechanisms, biodegradation as well as for application in the bioremediation of contaminated environments.
 
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giselledecarvalho.pdf (1.97 Mbytes)
Publishing Date
2008-03-20
 
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