title: Antioxidant defense system responses and role of nitrate reductase in the redox balance maintenance in Bradyrhizobium japonicum strains exposed to cadmium.
abstract: In this work, we evaluated the effects of cadmium (Cd) on the antioxidant defense system responses and the role of nitrate reductase (NR) in the redox balance maintenance in Bradyrhizobium japonicum strains. For that, B. japonicum USDA110 and its NR defective mutant strain (GRPA1) were used. Results showed that the addition of 10μM Cd did not modify the aerobic growth of the wild type strain while the mutant strain was strongly affected. Anaerobic growth revealed that only the parental strain was able to grow under this condition. Cd reduced drastically the NR activity in B. japonicum USDA110 and increased lipid peroxide content in both strains. Cd decreased reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio in B. japonicum USDA110 although, a significant increased was observed in the mutant GRPA1. GSH-related enzymes were induced by Cd, being more evident the increase in the mutant strain. This different behavior observed between strains suggests that NR enzyme plays an important role in the redox balance maintenance in B. japonicum USDA 110 exposed to Cd.
authors.affiliation: Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta 36 Km 601, 5800 Río Cuarto, Córdoba, Argentina. Electronic address: elianabianucci@yahoo.com.ar.
authors.forename: Eliana
authors.initials: E
authors.lastname: Bianucci
authors.forename: Cynthia
authors.initials: C
authors.lastname: Fullana
authors.forename: Ana
authors.initials: A
authors.lastname: Furlan
authors.forename: Stella
authors.initials: S
authors.lastname: Castro
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D020369:Bradyrhizobium / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D002104:Cadmium / Q000633:toxicity*; D005978:Glutathione / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D009154:Mutation; D050901:Nitrate Reductase / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects
chemical_list: D000975:Antioxidants; D002104:Cadmium; D050901:Nitrate Reductase; D005978:Glutathione
keywords: Bradyrhizobium japonicum; Cadmium; Glutathione; Nitrate reductase