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Remodulation of central carbon metabolic pathway in response to arsenite exposure in Rhodococcus sp. strain NAU-1.

Jain R, Adhikary H, Jha S, Jha A, Kumar GN - Microb Biotechnol (2012)

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).

View Article: PubMed Central - PubMed

Affiliation: Department of Biotechnology, ASPEE College of Horticulture and Forestry, Navsari Agricultural University, Navsari, Gujarat 396456, India.

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Arsenite oxidase and arsenate reductase activity in Rhodococcus sp. NAU‐1. CF, cytoplasmic fraction; MF, membrane fraction. The activities have been estimated in late log phase, without adding arsenite and after adding 1, 5 and 10 mM arsenite in the amended M9 minimal medium. All enzyme activities are expressed in μM min−1 mg−1 total protein. The values are depicted as mean ± SEM of three independent observations. ***P < 0.001, **P < 0.01. All parameters are compared with the control, i.e. culture without arsenite in medium.
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f3: Arsenite oxidase and arsenate reductase activity in Rhodococcus sp. NAU‐1. CF, cytoplasmic fraction; MF, membrane fraction. The activities have been estimated in late log phase, without adding arsenite and after adding 1, 5 and 10 mM arsenite in the amended M9 minimal medium. All enzyme activities are expressed in μM min−1 mg−1 total protein. The values are depicted as mean ± SEM of three independent observations. ***P < 0.001, **P < 0.01. All parameters are compared with the control, i.e. culture without arsenite in medium.

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.


Remodulation of central carbon metabolic pathway in response to arsenite exposure in Rhodococcus sp. strain NAU-1.

Jain R, Adhikary H, Jha S, Jha A, Kumar GN - Microb Biotechnol (2012)

Arsenite oxidase and arsenate reductase activity in Rhodococcus sp. NAU‐1. CF, cytoplasmic fraction; MF, membrane fraction. The activities have been estimated in late log phase, without adding arsenite and after adding 1, 5 and 10 mM arsenite in the amended M9 minimal medium. All enzyme activities are expressed in μM min−1 mg−1 total protein. The values are depicted as mean ± SEM of three independent observations. ***P < 0.001, **P < 0.01. All parameters are compared with the control, i.e. culture without arsenite in medium.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3815897&req=5

f3: Arsenite oxidase and arsenate reductase activity in Rhodococcus sp. NAU‐1. CF, cytoplasmic fraction; MF, membrane fraction. The activities have been estimated in late log phase, without adding arsenite and after adding 1, 5 and 10 mM arsenite in the amended M9 minimal medium. All enzyme activities are expressed in μM min−1 mg−1 total protein. The values are depicted as mean ± SEM of three independent observations. ***P < 0.001, **P < 0.01. All parameters are compared with the control, i.e. culture without arsenite in medium.
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.

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).

View Article: PubMed Central - PubMed

Affiliation: Department of Biotechnology, ASPEE College of Horticulture and Forestry, Navsari Agricultural University, Navsari, Gujarat 396456, India.

Show MeSH