• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1520-1526
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• 2009

We have identified the iscR (PA3815) gene encoding an iron-sulfur cluster assembly regulator homolog as one of the genes required for peroxide resistance in Pseudomonas aeruginosa PA14. Here, we present the phenotypic characterization of an iscR deletion mutant in terms of KatA expression, stress responses, and virulence. The iscR null mutant exhibited reduced KatA activity at the posttranslational level, hypersensitivity to hydrogen peroxide, and virulence-attenuation in Drosophila melanogaster and mouse peritonitis models. These phenotypes were fully restored by multicopy-based expression of katA. These results suggest that the requirement of IscR in P. aeruginosa is related to the proper activity of KatA, which is crucial for peroxide resistance and full virulence of this bacterium.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04a
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• pp.111-116
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• 2002

• Environmental Analysis Health and Toxicology
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• v.23 no.1
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• pp.23-32
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• 2008

In the present study, ROS detection of L5178Y cells that were treated with twenty test compounds in order to find out hydrogen peroxide ($H_2O_2$) induction for genotoxicity and carcinogenic toxicity. Twenty test compounds were consist of four classes, such as genotoxic carcinogens, genotoxic noncarcinogens, nongenotoxic carcinogens, and nongenotoxic noncarcinogens. Genotoxic carcinogens are 1,2-dibromoethane, glycidol, melphalan, diethylstilbestrol and urethane. Genotoxic noncarcinogens are 8-hydroxyquinoline, emodin, acetonitrile and diallylphthalate, L-ascorbic acid. Nongenotoxic carcinogens are methyl carbamate, O-nitrotoluene, 1,4-dioxane, tetrachloroethylene and 2,3,7,8-tetrachlorodibenzo-p-dioxin. And nongenotoxic noncarcinogens are D-mannitol, 1,2-dichlorobenzene, caprolactam, bisphenol A and chlorpheniramine maleate.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.05a
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• pp.91-92
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• 2003

Oxidative stress induced by reactive oxygen intermediates (ROIs) has been implicated in a variety of human diseases including cancer, diabetes, rheumatoid arthritis and neurodegenerative disorders. Hydrogen peroxide ($H_2O$$_2$), a representative ROI which is produced during the cellular redox process, can cause cell death via apoptosis and/or necrosis depending on its concentrations. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.153.1-153.1
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• 2003

Oxidative stress induced by reactive oxygen intermediates (ROIs) has been implicated in a variety of human diseases including cancer, diabetes, rheumatoid arthritis and neurodegenerative disorders. Hydrogen peroxide ($H_2O_2$), a representative ROI which is produced during the cellular redox process, can cause cell death via apoptosis and/or necrosis depending on its concentrations. l5-Deoxy-$D^{12, 14}$ prostaglandin $J_2$ (15d-$PGJ_2$), a dehydration product of prostaglandin $D_2$, has been reportd to possess a number of biological activities such as anti-inflammatory, anticarcinogenic, and antioxidative properties. (omitted)

• Journal of Applied Biological Chemistry
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• v.63 no.4
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• pp.357-363
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• 2020

Oxidative stress caused by the overproduction of reactive oxygen species (ROS) is known as an etiology of neurodegenerative diseases. Populus tomentiglandulosa (PT), a member of the Salicaceae family, is widely grown in Korea and has been reported to exert protective effects on cerebral ischemia by attenuating of oxidative stress and neuronal damage. In the present study, we investigated the antioxidant activity and neuroprotective effects of an ethanol extract and four fractions [n-butanol, ethyl acetate (EtOAc), chloroform, and n-hexane] of PT under in vitro and cellular systems. The extract and four fractions of PT showed 1,1-diphenyl-2-picrylhydrazyl (DPPH), •OH, and O2- radical scavenging activities in a dose-dependent manner. In particular, the EtOAc fraction of PT had the strongest DPPH, •OH, and O2- radical scavenging activities among the extract and other fractions. Therefore, we further investigated the neuroprotective effect of the EtOAc fraction of PT against oxidative stress in H2O2-induced SH-SY5Y cells. Treatment with H2O2 significantly decreased cell viability and lactate dehydrogenase (LDH) release, and it also increased the ROS levels compared to the normal group. However, treatment with the EtOAc fraction of PT significantly increased cell viability. Moreover, the EtOAc fraction of PT-treated group significantly suppressed ROS production and LDH release compared to the H2O2-induced control group. In conclusion, our findings indicated that PT had in vitro antioxidant activity and neuroprotective effects against oxidative stress. Therefore, PT could be used as a natural agent for protection against oxidative stress.

• Journal of Microbiology and Biotechnology
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• v.30 no.12
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• pp.1876-1884
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• 2020

Ethanol often accumulates during the process of wine fermentation, and mitophagy has critical role in ethanol output. However, the relationship between mitophagy and ethanol stress is still unclear. In this study, the expression of ATG11 and ATG32 genes exposed to ethanol stress was accessed by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). The result indicated that ethanol stress induced expression of the ATG11 and ATG32 genes. The colony sizes and the alcohol yield of atg11 and atg32 were also smaller and lower than those of wild type strain under ethanol whereas the mortality of mutants is higher. Furthermore, compared with wild type, the membrane integrity and the mitochondrial membrane potential of atg11 and atg32 exhibited greater damage following ethanol stress. In addition, a greater proportion of mutant cells were arrested at the G1/G0 cell cycle. There was more aggregation of peroxide hydrogen (H2O2) and superoxide anion (O2•-) in mutants. These changes in H2O2 and O2•- in yeasts were altered by reductants or inhibitors of scavenging enzyme by means of regulating the expression of ATG11 and ATG32 genes. Inhibitors of the mitochondrial electron transport chain (mtETC) also increased production of H2O2 and O2•- by enhancing expression of the ATG11 and ATG32 genes. Further results showed that activator or inhibitor of autophagy also activated or inhibited mitophagy by altering production of H2O2 and O2•. Therefore, ethanol stress induces mitophagy which improves yeast the tolerance to ethanol and the level of mitophagy during ethanol stress is regulated by ROS derived from mtETC.

• Plant Biotechnology Reports
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• v.5 no.3
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• pp.225-234
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• 2011

Arabidopsis mutants with T-DNA insertion in seven calmodulin genes (CAM) were used to determine the specific role of CAM in the tolerance of plants to oxidative stress induced by paraquat and hydrogen peroxide ($H_2O_2$) treatments. Arabidopsis calmodulin mutants (cam) were screened for seedling growth, seed germination, induced oxidative damage, and levels of ${\gamma}$-aminobutyric acid (GABA) shunt metabolites. Only the cam5-4 and cam6-1 mutants exhibited an increased sensitivity to paraquat and $H_2O_2$ during seed germination and seedling growth. In response to treatments with $3{\mu}M$ paraquat and 1 mM $H_2O_2$, only the cam5-4, cam6-1 mutants showed significant changes in malonaldehyde (MDA) levels in root and shoot tissues, with highly increased levels of MDA. In terms of the GABA shunt metabolites, GABA was significantly elevated in root and shoot tissues in response to the paraquat treatments in comparison to alanine and glutamate, while the levels of all shunt metabolites increased in root tissue but not in the shoot tissue following the $H_2O_2$ treatments. GABA, alanine and glutamate levels were significantly increased in root and shoot of the cam1, cam4, cam5-4, and cam6-1 mutants in response to paraquat (0.5, 1 and $3{\mu}M$), while they were increased only in the root tissue of the cam1, cam4, cam5-4, and cam6-1 mutants in response to $H_2O_2$ (200 and $500{\mu}M$, 1 mM). These data show that the cam5-4 and cam6-1 mutants were sensitive to the induced oxidative stress treatments in terms of seed germination, seedling growth, and oxidative damage. The accumulation of GABA shunt metabolites as a consequence of the induced oxidative stress treatments (paraquat and $H_2O_2$ treatments) suggests that the GABA shunt pathway and the accumulation of GABA metabolites may contribute in antioxidant machinery associated with reactive oxygen species and in the acquisition of tolerance in response to induced oxidative stress in Arabidopsis seedlings.

• Journal of Applied Biological Chemistry
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• v.63 no.4
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• pp.327-334
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• 2020

Oxidative stress is common cause of neurodegenerative diseases. The purpose of this study is to investigate the in vitro free radical scavenging activity and protective effect of three Glycyrrhiza species including Glycyrrhiza uralensis, G. glabra, and a new variety of Glycyrrihza (Shinwongam, SW) against hydrogen peroxide-induced oxidative stress in C6 glial cells. In vitro assays, radical scavenging activities of G. uralensis, G. glabra, and SW against 2,2-diphenyl-1-picrylhydrazyl, ·OH, and O2- increased as concentration-dependent manner. In addition, the SW was found to contain the highest polyphenol and flavonoid contents. The treatment of H2O2 to C6 glial cell induced oxidative stress, whereas G. uralensis, G. glabra, and SW significantly increased the cell viability as dose-dependent manner. In particular, SW exerted stronger protective effect on H2O2-induced cytotoxicity, than G. uralensis and G. glabra. Furthermore, reactive oxygen species (ROS) formation was significantly elevated by H2O2 in C6 glial cells. However, treatments of G. uralensis, G. glabra, and SW decreased ROS formation. In addition, SW decreased pro-inflammatory related protein expression levels such as inducible nitric oxide synthase and cyclooxygenase-2, compared to H2O2-treated control group. These results indicated that G. uralensis and G. glavra, especially SW, may be useful for preventing from oxidative stress-induced neuronal damage by regulating inflammatory reaction.

• Journal of Society of Preventive Korean Medicine
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• v.19 no.3
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• pp.141-154
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• 2015

Objective : In this paper, we investigated the anti-oxidative capacities and protective effects of water extract of palmul-tang (PMT) against Ultraviolet B(UVB)-induced oxidative damage in human keratinocytes(HaCaT). Method : To evaluate the anti-oxidative activities of PMT, we measured scavenging activities on 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical, hydroxyl radical, hydrogen peroxide, superoxide anion, lipid peroxidation and reducing power of PMT. To give an oxidative stress to HaCaT cells, UVB was irradiated with $40mJ/cm^2$ to HaCaT cells. To detect the protective effects of PMT against UVB, we measured cell viability, apoptotic bodies and reactive oxygen species(ROS) generation. Results : PMT showed the anti-oxidative activities by scavenging DPPH radical, hydroxyl radical, hydrogen peroxide, superoxide anion, lipid peroxidation. Also PMT showed high reducing values. The UVB-induced oxidative conditions led to the cell apoptosis. However, treatment with PMT reduced oxidative stress conditions, including inhibition of cell apoptosis and expression of ROS. Conclusion : PMT had anti-oxidative activities and exhibited protective effects against UVB on HaCaT cells. PMT would be useful for the development of cosmetics treating UVB-induced skin aging.