title: Metabolic Interference of sod gene mutations on catalase activity in Escherichia coli exposed to Gramoxone® (paraquat) herbicide.
abstract: Herbicides are continuously used to minimize the loss of crop productivity in agricultural environments. They can, however, cause damage by inhibiting the growth of microbiota via oxidative stress, due to the increased production of reactive oxygen species (ROS). Cellular responses to ROS involve the action of enzymes, including superoxide dismutase (SOD) and catalase (CAT). The objective of this study was to evaluate adaptive responses in Escherichia coli K-12 to paraquat, the active ingredient in the herbicide Gramoxone®. Mutant bacterial strains carrying deletions in genes encoding Mn-SOD (sodA) and Fe-SOD (sodB) were used and resulted in distinct levels of hydrogen peroxide production, interference in malondialdehyde, and viability. Mutations also resulted in different levels of interference with the activity of CAT isoenzymes and in the inactivation of Cu/Zn-SOD activity. These mutations may be responsible for metabolic differences among the evaluated strains, resulting in different patterns of antioxidative responses, depending on mutation background. While damage to the ΔsodB strain was minor at late log phase, the reverse was true at mid log phase for the ΔsodA strain. These results demonstrate the important role of these genes in defense against oxidative stress in different periods of growth. Furthermore, the lack of Cu/Zn-SOD activity in both mutant strains indicated that common metal cofactors likely interfere in SOD activity regulation. These results also indicate that E. coli K-12, a classical non-environmental strain, constitutes a model of phenotypic plasticity for adaptation to a redox-cycling herbicide through redundancy of different isoforms of SOD and CAT enzymes.
authors.affiliation: Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Campus Universitário de Uvaranas, Av. Carlos Cavalcanti, 4748, 84030-900 Ponta Grossa, Paraná, Brazil.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Gravina
authors.affiliation: Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Campus Universitário de Uvaranas, Av. Carlos Cavalcanti, 4748, 84030-900 Ponta Grossa, Paraná, Brazil.
authors.forename: Tatiane
authors.initials: T
authors.lastname: Dobrzanski
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, 05508-000 São Paulo, Brazil.
authors.forename: Luiz R
authors.initials: LR
authors.lastname: Olchanheski
authors.affiliation: Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Campus Universitário de Uvaranas, Av. Carlos Cavalcanti, 4748, 84030-900 Ponta Grossa, Paraná, Brazil.
authors.forename: Carolina W
authors.initials: CW
authors.lastname: Galvão
authors.affiliation: Departamento de Enfermagem e Saúde Pública, Universidade Estadual de Ponta Grossa, Campus Universitário de Uvaranas, Av. Carlos Cavalcanti, 4748, 84030-900 Ponta Grossa, Paraná, Brazil.
authors.forename: Péricles M
authors.initials: PM
authors.lastname: Reche
authors.affiliation: Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Campus Universitário de Uvaranas, Av. Carlos Cavalcanti, 4748, 84030-900 Ponta Grossa, Paraná, Brazil.
authors.forename: Sonia A
authors.initials: SA
authors.lastname: Pileggi
authors.affiliation: Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Av. Pádua Dias, 11, 13418-900 Piracicaba, São Paulo, Brazil.
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Azevedo
authors.affiliation: Department of Soil, Water, and Climate, and The BioTechnology Institute, University of Minnesota, St. Paul, MN 55108, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Sadowsky
authors.affiliation: Departamento de Biologia Estrutural, Molecular e Genética, Universidade Estadual de Ponta Grossa, Campus Universitário de Uvaranas, Av. Carlos Cavalcanti, 4748, 84030-900 Ponta Grossa, Paraná, Brazil. Electronic address: pileggimarcos@gmail.com.
authors.forename: Marcos
authors.initials: M
authors.lastname: Pileggi
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002374:Catalase / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D048168:Escherichia coli K12 / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D006540:Herbicides / Q000633:toxicity*; D006861:Hydrogen Peroxide / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D009154:Mutation / Q000187:drug effects; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects; D010269:Paraquat / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism
chemical_list: D000975:Antioxidants; D006540:Herbicides; D017382:Reactive Oxygen Species; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D010269:Paraquat
keywords: Knockout mutation; Malondialdehyde; Oxidative stress; Peroxide; Superoxide dismutase