• The Korean Journal of Ecology
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• v.26 no.3
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• pp.115-121
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• 2003

Leaves of two-week old seedlings of tomato (Lycopersicon esculentum) were treated with various concentrations (0∼100 M) of $CdCl_2$ for up to 9 days and subsequent growth of seedlings, symptoms of oxidative stress and isozyme activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POX) were investigated. Compared with the non-treated control, Cd exposure decreased biomass but increased Cd accumulation, hydrogen peroxide production and lipid peroxidation as malondialdehyde (MDA) formation in leaves and roots. Further studies on the developmental changes of isozyme activities showed that Fe-SOD, Cu/Zn-SOD and one of three APX isozymes decreased and CAT and one of four POX isozymes increased in leaves, whereas Fe-SOD, one of three POX isozymes and two of four APX isozymes decreased and CAT increased in roots, showing different expression of isozymes in leaves and roots with Cd exposure level and time. Based on our results, we suggest that the reduction of seedling growth by Cd exposure is the oxidative stress resulting from the over production of $H_2O_2$ and the insufficient activities of antioxidant enzymes particularly involved in the scavenging of $H_2O_2$. Further, the decreased activities of SOD and APX isozymes of chloroplast origin, the increased activities of CAT and POX and high $H_2O_2$ contents with Cd exposure might indicate that Cd-induced oxidative stress starts outside chloroplast.

• Journal of Ecology and Environment
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• v.30 no.3
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• pp.257-264
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• 2007

Over-expression of a copper/zinc superoxide dismutase (Cu/ZnSOD) resulted in substantially increased tolerance to cadmium exposure in Arabidopsis thaliana. Lower lipid peroxidation and $H_2O_2$ accumulation and the higher activities of $H_2O_2$ scavenging enzymes, including catalase (CAT) and ascorbate peroxidase (APX) in transformants (CuZnSOD-tr) compared to untransformed controls (wt) indicated that oxidative stress was the key factor in cadmium tolerance. Although progressive reductions in the dark-adapted photochemical efficiency (Fv/Fm) and quantum efficiency yield were observed with increasing cadmium levels, the chlorophyll fluorescence parameters were less marked in CuZnSOD-tr than in wi. These observations indicate that oxidative stress in the photosynthetic apparatus is a principal cause of Cd-induced phytotoxicity, and that Cu/ZnSOD plays a critical role in protection against Cd-induced oxidative stress.

• The Korean Journal of Mycology
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• v.47 no.3
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• pp.219-232
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• 2019

Chemicals related to hydrogen peroxide ($H_2O_2$) and nitric oxide (NO) generations were exogenously applied to Fusarium oxysporum f. sp. fragariae (Fof) causing Fusarium wilt disease in strawberry plants, and regulations of in vitro conidial germination and mycelial growth of the fungus by the chemical treatments were evaluated. $H_2O_2$ drastically reduced the conidial germination of Fof in a dose-dependent manner, and treatment with 3-amino-1,2,4-triazole (3-AT) catalase inhibitor also led to dose-dependent inhibition of conidial germination but relatively moderately. Gradual decreases in mycelial growth of Fof were found by high concentrations of $H_2O_2$, whilst exogenous 3-AT slightly increased the mycelial growth. Increasing sodium nitroprusside (SNP) NO donor, $N^G$-nitro-l-arginine methyl ester (L-NAME) NO synthase (NOS)-inhibitor and tungstate nitrate reductase (NR) inhibitor led to dose-dependent reductions in conidial germination of Fof in quite different levels. SNP conversely increased the mycelial growth but increasing L-NAME moderately decreased the mycelial growth. Tungstate strongly enhanced mycelial growth. Differentially regulated in vitro mycelial growths of Fof were demonstrated by SNP, L-NAME and tungstate with or without $H_2O_2$ supplement. Superoxide anion production was also regulated during the mycelial growth of Fof by nitric oxide. These results show that $H_2O_2$ and NO-associated enzymes can be suggested as fungal growth regulators of Fof as well as eco-friendly disease-managing agents in strawberry production fields.

• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.923-929
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• 2016

The purpose of this study was to evaluate the protective effect of $PineXol^{(R)}$ on $H_2O_2$-induced cell death in SK-N-MC cells, and in early stage focal ischemia rodent model. SK-N-MC cells were pre-treated with $200{\mu}M$ $H_2O_2$ or various concentrations of $PineXol^{(R)}$ (10, 30, and 50 pg/mL) for 24 h, and then exposed to $H_2O_2$ for 3 h. Cell death was assessed by the CCK-8 assay, reactive oxygen species (ROS) assay, and lactate and dehydrogenase (LDH) release assay. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) expressions were also analyzed by western blotting. Focal ischemia rodent model was used as the in vivo model, and different concentrations of $PineXol^{(R)}$ (1, 10, and 100 mg/kg) were administered. One week after administration, reduction of infarct volume was analyzed by TTC staining. Cell viability of $H_2O_2$-treated SK-N-MC cells significantly increased by pre-treatment of $PineXol^{(R)}$ (p<0.05). $PineXol^{(R)}$ pre-treatment also induced significant decrease of ROS and LDH expressions. However, $PineXol^{(R)}$ did not affect the infarct volume. These results suggest that $PineXol^{(R)}$ has significant neuroprotective effect in vitro, but statistical significance was not confirmed in the in vivo focal ischemia model.

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.223.2-224
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• 2000

No Abstract, See Full Text

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.2
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• pp.233-239
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• 2017

Intracellular calcium ($Ca^{2+}$) oscillation is an initial event in digestive enzyme secretion of pancreatic acinar cells. Reactive oxygen species are known to be associated with a variety of oxidative stress-induced cellular disorders including pancreatitis. In this study, we investigated the effect of hydrogen peroxide ($H_2O_2$) on intracellular $Ca^{2+}$ accumulation in mouse pancreatic acinar cells. Perfusion of $H_2O_2$ at $300{\mu}M$ resulted in additional elevation of intracellular $Ca^{2+}$ levels and termination of oscillatory $Ca^{2+}$ signals induced by carbamylcholine (CCh) in the presence of normal extracellular $Ca^{2+}$. Antioxidants, catalase or DTT, completely prevented $H_2O_2$-induced additional $Ca^{2+}$ increase and termination of $Ca^{2+}$ oscillation. In $Ca^{2+}$-free medium, $H_2O_2$ still enhanced CCh-induced intracellular $Ca^{2+}$ levels and thapsigargin (TG) mimicked $H_2O_2$-induced cytosolic $Ca^{2+}$ increase. Furthermore, $H_2O_2$-induced elevation of intracellular $Ca^{2+}$ levels was abolished under sarco/endoplasmic reticulum $Ca^{2+}$ ATPase-inactivated condition by TG pretreatment with CCh. $H_2O_2$ at $300{\mu}M$ failed to affect store-operated $Ca^{2+}$ entry or $Ca^{2+}$ extrusion through plasma membrane. Additionally, ruthenium red, a mitochondrial $Ca^{2+}$ uniporter blocker, failed to attenuate $H_2O_2$-induced intracellular $Ca^{2+}$ elevation. These results provide evidence that excessive generation of $H_2O_2$ in pathological conditions could accumulate intracellular $Ca^{2+}$ by attenuating refilling of internal $Ca^{2+}$ stores rather than by inhibiting $Ca^{2+}$ extrusion to extracellular fluid or enhancing $Ca^{2+}$ mobilization from extracellular medium in mouse pancreatic acinar cells.

• Korean Journal of Food Science and Technology
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• v.19 no.6
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• pp.471-474
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• 1987

The formation of superoxide anion (${\cdot}O^{-}_2$)and hydrogen peroxide ($H_2O_2$) during linoleic acid peroxidation were investigated in linoleic acid-aqueous system at $37^{\circ}C$. Superoxide anion was rapidly generated in the early stage of peroxidation, marked to 0.375 (absorbance at 560mm) in the 12mM linoleic acid (POV below 80millieq./kg) incubated for 1 day and then decreased with time-elapsed. Hydrogen peroxide was also rapidly generated in the early stage of peroxidation regardless of linoleic acid concentration. And, superoxide dismutase(SOD) and catalase greatly inhibited the formation of superoxide anion and hydrogen peroxide, respectively.

• Journal of Environmental Science International
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• v.21 no.12
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• pp.1435-1447
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• 2012

The present study was conducted to determine the effect of hexaconazole (HEX), a triazole fungicide, on the growth, yield, photosynthetic response and antioxidant potential in cucumber (Cucumis sativus L.) plants subjected to UV-B stress. UV-B radiation and HEX were applied separately or in combination to cucumber seedlings. The growth parameters were significantly reduced under UV-B treatment, however, this growth inhibition was less in HEX treated plants. HEX caused noticeable changes in plant morphology such as reduced shoot length and leaf area, and increased leaf thickness. HEX was quite persistent in inhibiting shoot growth by causing a reduction in shoot fresh and dry weight. HEX noticeably recovered the UV-B induced inhibition of biomass production. Significant accumutation in anthocyanin and flavonoid pigments in the leaves occurred as a result of HEX or UV-B treatments. HEX permitted the survival of more green leaf tissue preventing chlorophyll content reduction and higher quantum yield for photosystemII under UV-B exposure. HEX treatment induced a transient rise in ABA levels in the leaves, and combined application of HEX and UV-B showed a significant enhancement of ABA content which activates $H_2O_2$ generation. UV-B exposure induced accumulation of $H_2O_2$ in the leaves, while HEX prevented UV-B induced increase in $H_2O_2$, indicating that HEX serves as an antioxidant agent able to scavenge $H_2O$ to protect cells from oxidative damage. An increase in the ascorbic acid was observed in the HEX treated cucumber leaves affecting many enzyme activities by removing $H_2O_2$ during photosynthetic processes. The activities of antioxidant enzymes including catalase(CAT), ascorbate peroxidase(APX), superoxide dismutase(SOD) and peroxidase(POD) in the leaves in the presence of HEX under UV-B stress were higher than those under UV-B stress alone. These findings suggest that HEX may participate in the enhanced tolerance to oxidative stress. From these results it can be concluded that HEX moderately ameliolate the effect of UV-B stress in cucumber by improving the components of antioxidant defense system.

• Journal of Microbiology and Biotechnology
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• v.7 no.5
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• pp.356-359
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• 1997

To study the relationship between oxygen tolerance and enzyme activity in the oxygen metabolism of bifidobacteria, the activities of catalase, superoxide dismutase (SOD), NADH oxidase and NADH peroxidase from six typical bifidobacteria and other bacteria were assayed by spectrophotometry. Catalase activity was hardly detected in any of the bifidobacteria tested. SOD activity was detected in every species including the Clostridium species. In particular SOD activity was notably high in the aerosensitive Bifidobacterium adolescentis. This fact indicates that SOD activity is not a critical factor to ensure aerotolerance. Aerosensitive B. adolescentis showed very low NADH oxidative enzyme activity whereas other aerotolerant bifidobacteria exhibited considerable activity for the enzymes. It seems that detoxification of $H_2O_2$ by NADH oxidative enzymes might be an important factor in improving for aerotolerant bifidobacteria survival rates in an oxygen environment.

• KSBB Journal
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• v.8 no.4
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• pp.397-404
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• 1993

Two strains were isolated from the vinegar of Korean traditional fermented rice wine and the vine gar of fermented persimmon, respectively. These strains, designated as KM and BPV, were identified as the genus Acetobacter with respect to morphological, physiological, and biochemical characteristics. The Isolates oxidized ethanol to acetate and over-oxidized acetate or lactate to CO2 and H2O. They were positive in catalase test, while being negative in oxidase, gelatin liquefaction, VP test, H2O production and indole formation tests. No ${\gamma}$-pyrones ware produced from glucose and fructose. KM was tolerant of 11% ethanol while BPV was relatively sensitive to ethanol at a higher concentration than 5%. The guanine-plus-cytosine contents of the DNA of KM and BPV strains were 53.8 and 56.6 mol%, respectively. The cellular fatty acid compositions contained in these isolates were saturated straightchain C14:0 and C16:0,, and unsaturated straight-chain C18:1. Major ubiquinone system of KM was Q-9, but that of BPV was Q-10. In morphophysiological and biochemical aspects, KM strain was similar to Acetobacter pasteurianus. However, BPV strain was different from other Acetobacter type strains.