Remodulation of central carbon metabolic pathway in response to arsenite exposure in Rhodococcus sp. strain NAU-1.
Bottom Line: Assays confirmed the presence of membrane bound arsenite oxidase and cytoplasmic arsenate reductase in NAU-1.Specific activities of antioxidant enzymes (catalase, ascorbate peroxidase, superoxide dismutase and glutathione S-transferase) increased in dose-dependent manner with arsenite, whereas glutathione reductase activity decreased with increase in As(III) concentration.Enzyme assays revealed the increase in direct oxidative and glyoxylate pathway in Rhodococcus NAU-1 in the presence of As(III).
Affiliation: Department of Biotechnology, ASPEE College of Horticulture and Forestry, Navsari Agricultural University, Navsari, Gujarat 396456, India.Show MeSH
Mentions: Biotransformation potential of arsenic‐tolerant Rhodococcus sp. strain NAU‐1 was analysed by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP‐OES). In intracellular samples the G6PDH enzyme activity was found to be 4.94 ± 0.38 whereas in extracellular sample only 0.04 ± 0.00 μM min−1 mg−1 total protein. In the study, intracellular and extracellular AsIII concentrations were found to be 0.054 ± 0.003 mM and 1.14 ± 0.12 mM respectively. Similarly, intracellular and extracellular concentrations of AsV were 0.051 ± 0.007 mM and 2.56 ± 0.09 mM respectively. Arsenite oxidase activity was localized mainly in the membrane fraction compared with cytosolic fraction. Also, a positive correlation between membrane bound specific arsenite oxidase activity and AsIII concentration was observed (Fig. 3). Unlike arsenite oxidase, arsenate reductase activity was more prominent in cytoplasmic fraction (10.5 ± 0.13 μM min−1 mg−1 total protein) than the membrane fraction (0.12 ± 0.01 μM min−1 mg−1 total protein) at 5 mM AsV (Fig. 3). No arsenite oxidase and arsenate reductase activities were detected in any of heat‐killed controls.
Affiliation: Department of Biotechnology, ASPEE College of Horticulture and Forestry, Navsari Agricultural University, Navsari, Gujarat 396456, India.