Atividade antioxidante do exopolissacarídeo bacteriano extraído de Gluconacetobacter diazotrophicus

• Ano de defesa: 2014
• Autor(a) principal: Gonçalves, Talyta Thereza
• Orientador(a): Meneses, Carlos Henrique Salvino Gadelha
• Banca de defesa: Lima, Liziane Maria de , Araújo, Demétrius Antônio Machado de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual da Paraíba
• Programa de Pós-Graduação: Mestrado em Ciências Agrárias
• Departamento: Ciências Agrárias
• País: BR
• Palavras-chave em Português: Bactéria endofítica; Fixação biológica de nitrogênio; Bioquímica; Exopolímero
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS
• Link de acesso: http://tede.bc.uepb.edu.br/tede/jspui/handle/tede/2024

The Biological Nitrogen Fixation (BNF) is a process of high energy demand dependent on environmental factors such as oxygen and fixed nitrogen levels, which are detected by proteins that are part of signal transduction systems. The need to monitor the concentrations of fixed nitrogen and external oxygen and provide enough energy to sustain the BNF imposed regulatory principles that differ between diazotrophic organisms and depend on the physiology of the plant host. Although several studies have been conducted on the physiology and BNF of G. diazotrophicus, it has not been possible to make a broad physiological characterization for the plant-microbe association. G. diazotrophicus requires exopolysaccharides to form an endophytic interaction, nitrogen fixing, success with sugar cane and other grasses. In addition, during the initial stages of interaction, G. diazotrophicus is faced with an oxidative burst, caused by the plant, which should be overcome. In this study, levels of exopolysaccharides were positively correlated with survival in hydrogen peroxide (H 2 O 2 ). Damage caused by H were mitigated when the EPS was the co-cultured with cells deficient in EPS production. The purified EPS is able to reduce in vitro the levels of H 2 O 2 2 . This suggests a potential as an additional protective function against H 2 O 2 O 2 exopolysaccharide during the early interaction of bacteria with the plant