• Journal of Microbiology and Biotechnology
• /
• v.14 no.3
• /
• pp.466-469
• /
• 2004

The recombinant bioluminescent Escherichia coli strains, DPD2511 and TV 1061 containing the katG and grpE promoters, respectively, from Vibrio fischeri fused to luxCDABE, were used to detect the adaptive and repair responses to oxidative damage caused by hydrogen peroxide $(H_2O_2)$, and protein damage due to phenol. The response ratio, represented as the bioluminescence induced in subsequent inductions of DPD2511 and TV1061 with the mother cells previously induced by each chemical, i.e., $H_2O_2$ and phenol during the previous induction stage, decreased suddenly compared with the ratio of the control culture of each strain, meaning there is a possible adaptive response to stress caused by chemicals. Protein damage due to phenol was completely repaired by the second culturing after the initial induction, as was oxidative damage caused by $H_2O_2$ which was also rapidly repaired, as detected by the recovery of bioluminescence level. This result suggests that E. coli promptly adapt and repair oxidative and protein damage by $H_2O_2$ and phenol completely.

• Journal of Microbiology and Biotechnology
• /
• v.24 no.8
• /
• pp.1118-1122
• /
• 2014

The present study shows that DR1114 (Hsp20), a small heat shock protein of the radiation-resistant bacterium Deinococcus radiodurans, enhances tolerance to hydrogen peroxide ($H_2O_2$) stress when expressed in Escherichia coli. A protein profile comparison showed that E. coli cells overexpressing D. radiodurans Hsp20 (EC-pHsp20) activated the redox state proteins, thus maintaining redox homeostasis. The cells also showed increased expression of pseudouridine (psi) synthases, which are important to the stability and proper functioning of structural RNA molecules. We found that the D. radiodurans mutant strain, which lacks a psi synthase (DR0896), was more sensitive to $H_2O_2$ stress than wild type. These suggest that an increased expression of proteins involved in the control of redox state homeostasis along with more stable ribosomal function may explain the improved tolerance of EC-pHsp20 to $H_2O_2$ stress.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.50 no.5
• /
• pp.520-526
• /
• 2017

Carnosine was recently reported to protect against the DNA damage induced by oxidative stress. In this study, we investigated the protective effect of eel Anguilla japonica carnosine extracts prepared using different methods (heat treatment extracts, HTEs; ion exchange chromatography, IEC; ultrafiltration permeation, UFP) on leukocyte DNA damage using the comet assay. Human leukocytes were incubated with extracts of eel carnosine at concentrations (of 10, 50, $100{\mu}g/mL$), and then subjected to an oxidative stimulus [$200{\mu}M$ hydrogen peroxide ($H_2O_2$)]. Pretreatment of the cells for 30 min with carnosine significantly reduced the genotoxicity of $H_2O_2$ measured as DNA strand breaks. The protective effects of the three types of extract (HTE, IEC, and UFP) increased with concentration. At the highest concentration (100 g/mL). there were no statistical differences in oxidative damage between each extract treatment and PBS-treated negative controls. When leukocytes were incubated with carnosine for 30 min after exposure to $H_2O_2$. the protective ability of each extract changed. Therefore, eel carnosine inhibits the $H_2O_2$ induced damage to cellular DNA in human leukocytes, supporting the protective effect of this compound against oxidative damage.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.7
• /
• pp.1224-1233
• /
• 2016

The present study assessed the effects of an aqueous extract of Acanthopanax koreanum root (AE) and of AE following fermentation by lactic acid bacteria (Lactobacillus plantarum and Bifidobacterium bifidum) (AEF) on human skin fibroblast HS68 cells exposed to ultraviolet B (UVB) irradiation and oxidative stress. AEF effectively antagonized the senescence-associated β-galactosidase staining and upregulation of p53 and p21^Cip1/WAF1 induced by UVB or H₂O₂ treatment in HS68 cells. It also exhibited excellent antioxidant activities in radical scavenging assays and reduced the intracellular level of reactive oxygen species induced by UVB or H₂O₂ treatment. The antioxidant and antisenescent activities of AEF were greater than those of nonfermented A. koreanum extract. AEF significantly repressed the UVB- or H₂O₂-induced activities of matrix metalloproteinase (MMP)-1 and -3, overexpression of MMP-1, and nuclear factor κB (NF-κB) activation. This repression of NF-κB activation and MMP-1 overexpression was attenuated by a mitogen-activated protein kinase activator, suggesting that this AEF activity was dependent on this signaling pathway. Taken together, these data indicated that AEF-mediated antioxidant and anti-photoaging activities may produce anti-wrinkle effects on human skin.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.7
• /
• pp.605-609
• /
• 2005

Chemical mechanical polishing (CMP) of Ni was performed by the various ratios of four kinds of oxidizers and an addition of alumina powders as an abrasive in each slurry with the different oxidizers. Moreover, the interaction between the Ni and the each oxidizer was discussed by potentiodynamic polarization measurement, in order to compare the effects of Ni-CMP and electrochemical characteristics on the Ni with the different oxidizers. As an experimental result, the removal rate of Ni reached a maximum at 1 $vol\%$ of $H_2O_2$. Also the removal rates of Ni increased with the audition of alumina abrasives in each slurry. The potentiodynamic polarization of Ni under dynamic condition showed a significant difference in electrochemical behavior by addition of $H_2O_2$ in solutions. Ni showed the perfect passivation behavior in solution without $H_2O_2$ under potentiodynamic polarization condition, while active dissolution dominates in solution with the addition of $H_2O_2$. The results indicate that the surface chemistry and electrochemical characteristics of Ni play an important role in controlling the polishing behavior of Ni.

• The Journal of Internal Korean Medicine
• /
• v.19 no.1
• /
• pp.442-451
• /
• 1998

This study was carried out to examine mechanisms by which Holotrichia (HTC) produces protective effect against renal cell injury. HTC extraction (5%) prevented $H_2O_2(50mM)$-induced LDH release and lipid peroxidation in renal cortical slices. When slices were treated with 5% HTC extraction, cellular glutathione content and the superoxide dismutase activity were not altered in control and $H_2O_2$-treated tissues. When slices were treated with 50 mM $H_2O_2$, the catalase activity was significantly inhibited, which was completely restored by addition of 5% HTC. Treatment of slices with 5% HTC extraction increased the glutation peroxidase activity in $H_2O_2$-treated tissues. These results suggest that HTC prevents oxidant-induced cell injury and lipid peroxidation by increasing the activities of catalase and glutathione peroxidase in renal cortical slices.

• Journal of Korean Society on Water Environment
• /
• v.30 no.6
• /
• pp.653-657
• /
• 2014

Effects of $H_2O_2$ addition for fenton oxidation on iron coagulation for treatment of phosphorus species, such as orthophosphate, metaphosphate, pyrophosphate, organic phosphate, were investigated. The effects of coagulant dosage, hydrogen peroxide dosage and the combined sequence ferric coagulation and $H_2O_2$ addition for fenton oxidation and coagulation were studied. The characteristics of floc growth rate were monitored using the PDA. The removal efficiencies of phosphorus species by iron coagulation were increased as Fe/P molar ratio increased. However, the removal efficiencies of metaphosphate, pyrophosphate, organic phosphate by a ferric coagulation were not increased as Fe/P molar ratio increased. The removal efficiency of metaphosphate, pyrophosphate, organic phosphate was increased by using iron coagulation and $H_2O_2$ addition for fenton oxidation. The result indicated that non-reactive phosphorus after iron coagulation was changed to reactive phosphorus by $H_2O_2$ addition for fenton oxidation and the oxidized iron enhanced the coagulation efficiencies.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.18 no.6
• /
• pp.515-520
• /
• 2005

CMP(chemical mechanical polishing) process has been attracted as an essential technology of multi-level interconnection. Also CMP process got into key process for global planarization in the chip manufacturing process. In this study, potentiodynamic polarization was carried out to investigate the influences of $H_2O_2$ concentration and metal oxide formation through the passivation on tungsten and titanium. Fortunately, the electrochemical behaviors of tungsten and titanium are similar, an one may expect. As an experimental result, electrochemical corrosion of the $5\;vol\%\;H_2O_2$ concentration of tungsten and titanium films was higher than the other concentrations. According to the analysis, the oxidation state and microstructure of surface layer were strongly influenced by different oxidizer concentration. Moreover, the oxidation kinetics and resulting chemical state of oxide layer played critical roles in determining the overall CMP performance. Therefore, we conclude that the CMP characteristics tungsten and titanium metal layer including surface roughness were strongly dependent on the amounts of hydrogen peroxide oxidizer.

• Journal of the Korean Wood Science and Technology
• /
• v.28 no.4
• /
• pp.17-24
• /
• 2000

The peroxidase activity was localized cytochemically to get an insight into its precise function in lignin biosynthesis. In this work, cerium chloride ($CeCl_3$) was used as a trapping agent for hydrogen peroxide ($H_2O_2$) generated from peroxidase. Seasonal variation of peroxidase activities in cambial region of Populus, Pinus, and Ginkgo was investigated at subcellular levels. Under transmission electron microscopy, electron dense deposits of cerium perhydroxide formed by reaction with $H_2O_2$ were observed in cambium and its immediate derivatives. The staining with $CeCl_3$ in cambium varied with growth seasons. The strongest $H_2O_2$ accumulation, regardless of tree species, appeared in May. Staining pattern of $CeCl_3$ in the cambium of poplar indicated that the production of peroxidase started in March before the opening of buds and reached the highest in May and then declined in August. Ginkgo and Pinus showed relatively late generation of $H_2O_2$ production when compared with Populus. Although Ginkgo and Pinus are classified into gymnosperms, however, the generation of peroxidase production and its duration was different from each other. Little staining appeared in all the tree samples collected in September before falling the leaves.

• Proceedings of the KIEE Conference
• /
• 2006.10a
• /
• pp.93-94
• /
• 2006

In this research, the enhancement of electron-transfer activity of hemoglobin (Hb) in dodecanoic acid film was investigated for the first time. This type of composite film was made on glassy carbon electrode by casting method. Cyclic voltammetric result of the modified electrode displays a well defined redox peaks which was attributed to the direct electrochemical response of Rb. Our results illustrate that Rb exchange electrons directly with electrode and exhibits the characteristics of peroxidase. When we apply this modified electrode as a biosensor, it gives excellent performances in the electrocatalytic reduction of hydrogen peroxide ($H_{2}O_{2}$). Through the optimal conditions, the proposed biosensor shows the linear range for H2O2 determination was from $1{\times}10^{-5}$ to $1.25{\times}10^{-4}mol/L$ with a detection limit of $1{\times}10^{-7}mol/L$. The biosensor retained more than 90% of the initial response after 14 days.