• Microbiology and Biotechnology Letters
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• v.26 no.2
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• pp.167-172
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• 1998

In batch cultures of Brevibacterium ketoglutamicum for the L-ornithine production in which the pH and dissolved oxygen concentration were regulated constant, the profiles of redox potential were observed in parallel with the profiles of state variables such as cell, glucose, and ornithine concentrations. It was found that the redox potential had a close relationship with cell concentration and was also affected by ornithine concentration. The effects of ornithine and glucose on redox potential were examined in a separate series of experiments. Based on the experimental results, a correlation of redox potential to glucose, cell and ornithine concentrations has been proposed. The proposed correlation can be used for on-line estimation of ornithine concentration from on-line data of redox potential, glucose concentration, and cell concentration.

• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.76-81
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• 1991

- The effect of redox potential (ORP) on lysine production by a leucine auxotrophic regulatory mutant of Corynebacterium glutclmicum on molasses medium was investigated in a 2-1 jar fermentor at pH 6.9 and $32^{\circ}C$. At a dilution rate of D=O.l $h ^1$, a maximum yield of Yr,,s=0.24 was obtained in either carbon- or leucine-limited chemostat where the redox potential was between -60 mV and - 100 mV. This level of redox potential corresponded to moderate oxygen deficiency. Under a high oxygen deficient condition of the redox potential of - 130 rnV (oxygen-limited chemostat), all the kinetic parameters such as $Y_[p/s}, q_s\; and \; q_p$ were decreased significantly and significant amounts of byproducts including glycine, alanine and valine were accumulated in the culture, indicating that the control of redox potential is important in lysine fermentation. At the redox potential of - 40 mV, on the other hand, large quantities of arginine (up to 0.38g/l) and glutamic acid (up to 0.12 g/l) were produced. A maximum lysine productivity of 2.41 g/l/h was achieved at - 66 mV under a carbon-limited condition.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.1043-1046
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• 2004

The stability and electrochemical properties of a self-assembled layer of spinach ferredoxin on a quartz substrate and on a highly oriented pyrolytic graphite electrode were investigated. To fabricate the ferredoxin self-assembly layer, dimyristoylphosphatidylcholine was first deposited onto a substrate for ferredoxin immobilization. Surface analysis of the ferredoxin layer was carried out by atomic force microscopy to verify the ferredoxin immobilization. To verify ferredoxin immobilization on the lipid layer and to confirm the maintenance of redox activity, absorption spectrum measurement was carried out. Finally, cyclic-voltammetry measurements were performed on the ferredoxin layers and the redox potentials were obtained. The redox potential of immobilized ferredoxin had a formal potential value of -540 mV. It is suggested that the redox-potential measurement of self-assembled ferredoxin molecules could be used to construct a biosensor and biodevice.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.10 no.S_2
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• pp.65-71
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• 2001

The chemical behavior and properties related to the redox state of environmental pollutants were investigated using electrochemical methods. Measurements were taken of variations in the redox potential and cyclic polarization current. The results established the influence of various factors, including concentration, temperature, salt, and pH, on the redox potential and current. These factors were determined to effect the result of the redox reaction. Optimum conditions were also established for each case. It was clearly established that the electrode reaction was from a reversible to an irreversible process, plus it was also mixing reaction current controlled.

• Journal of Wetlands Research
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• v.6 no.2
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• pp.65-71
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• 2004

The most significant effect of excess water in wetlands is the isolation of the soil from the atmosphere and the prevention of O2 from diffusing into soil. The blockage of atmospheric O2 induces biological and chemical processes that change soil from oxidized into reduced state. When dry soil develop into hydric soil, redox potential is dropping. The redox potential is a indicator of hydric soil and affect chemical function of wetlands. To reveal characteristics of wetland soil, redox potential was measured in Jinkwannaedong ecological conservation area from May in 2003 to March in 2004. Redox potentials in May ranged from 5 mV at 25 cm depth to 200 mV at 10 cm depth. It decreased to about -200 m V at all depths and continued until October. In winter, redox potential was slowly increased; it was the highest at 5 cm depth and lowest at 20 cm depth. Annual variations of redox potential in 20 cm depth showed the same pattern at 5 sites; low in growing season and high in non-growing season. This results indicates that soils of study sites are in hydric state and methanogenesis is occurring in Jinkwannaedong ecological conservation area.

• Molecules and Cells
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• v.39 no.1
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• pp.72-76
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• 2016

Cell death pathways such as apoptosis can be activated in response to oxidative stress, enabling the disposal of damaged cells. In contrast, controlled intracellular redox events are proposed to be a significant event during apoptosis signaling, regardless of the initiating stimulus. In this scenario oxidants act as second messengers, mediating the post-translational modification of specific regulatory proteins. The exact mechanism of this signaling is unclear, but increased understanding offers the potential to promote or inhibit apoptosis through modulating the redox environment of cells. Peroxiredoxins are thiol peroxidases that remove hydroperoxides, and are also emerging as important players in cellular redox signaling. This review discusses the potential role of peroxiredoxins in the regulation of apoptosis, and also their ability to act as biomarkers of redox changes during the initiation and progression of cell death.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.10 no.S_4
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• pp.173-179
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• 2001

The chemical behavior and properties of the redox state of environmental pollutants was investigated using electrochemical methods. The purpose was to measure the variations in the redox reaction of differential pulse polarograms and cyclic voltammograms. The results observed the influences on redox potential and current of various factors including concentration, temperature, salt, and pH. These were established factors as the effect of the redox reaction. It can be clearly recognized that the electrode reaction are from reversible to irreversible processes. Also, it was mixing with reaction current controlled.

• Journal of Environmental Science International
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• v.11 no.2
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• pp.131-137
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• 2002

The chemical behavior and properties on the redox state of environmental pollutant has been investigated by electrochemical methods. We carried out to measure the variations in the redox reaction of differential pulse polarogram and cyclic voltammogram. The results observed the influences on redox potential and current of various factors with temperature and pH. These were established factors as the effect of the redox reaction. It can be clearly recognized that the electrode reaction are from qusi-reversible to irreversible processes. Also, it was mixing with reaction current controlled. The bits-phenol A in the waste water was made to compound with cobalt ion and it take away from the separation into compound. The $Co(BPA)_2$ compound was not found to be dissociation in waste water. However, this compound is avery unstable(K=1.02) and for a while, it was to be a dissociation. Therefore, we believed that it was likely to a toxic substance.

• Journal of the Korean Ceramic Society
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• v.48 no.3
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• pp.205-210
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• 2011

The dependence of sulfur redox behavior and its diffusivity on temperature and composition was studied in mixed alkali silicate melts by means of square wave voltammetry (SWV) at different frequencies in a temperature range of $1000^{\circ}C$ to $1400^{\circ}C$. The voltammograms showed two reduction peaks at high frequency but only one peak at low frequency. Irrespective of $K_2O/(Na_2O+K_2O)$, each peak potential due to reduction of $S^{6+}$ to $S^{4+}$ and $S^{4+}$ to $S^0$ moved toward a negative direction with temperature decrease, and the peak current showed a strong dependence on frequency at a constant temperature. However, the compositional dependence of the peak potential showed an inconsistent behavior with an increase of $K_2O$. The mixed alkali effect was not observed in sulfur diffusion. This inconsistency of both peak potential and diffusion for compositional dependence may be derived from the strong volatilization of sulfur in melts.

• BMB Reports
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• v.35 no.2
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• pp.194-198
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• 2002

Eukaryotic replication protein A (RPA) is a single-stranded(ss) DNA binding protein with multiple functions in DNA replication, repair, and genetic recombination. The 70-kDa subunit of eukaryotic RPA contains a conserved four cysteine-type zinc-finger motif that has been implicated in the regulation of DNA replication and repair. Recently, we described a novel function for the zinc-finger motif in the regulation of human RPA's ssDNA binding activity through reduction-oxidation (redox). Here, we show that yeast RPA's ssDNA binding activity is regulated by redox potential through its RPA32 and/or RPA14 subunits. Yeast RPA requires a reducing agent, such as dithiothreitol (DTT), for its ssDNA binding activity. Also, under non-reducing conditions, its DNA binding activity decreases 20 fold. In contrast, the RPA 70 subunit does not require DTT for its DNA binding activity and is not affected by the redox condition. These results suggest that all three subunits are required for the regulation of RPA's DNA binding activity through redox potential.