• Proceedings of the PSK Conference
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• 2003.10b
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• pp.102.1-102.1
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• 2003

Phospholipase A$_2$(PLA$_2$) catalyzes the hydrolysis of the sn-2 position of membrane glycerophospholipids to liberate arachidonic acid(AA), a precursor of eicosanoids including prostaglandins(PGs) and leukotrienes (LTs). The same reaction also produces lyso-phospholipids. So far, at least 19 enzymes that possess PLA2 activity have been identified, consists of low-molecular-weight, Ca$\^$2+/-requiring, secretory enzymes that have been implicated in a number of biological processes, such as modification of eicosanoid generation, inflammation, host defense, and atherosclerosis. (omitted)

• Nutritional Sciences
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• v.7 no.3
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• pp.127-132
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• 2004

The current study examined the effects of mulberry fruit on the antioxidative defense systems and oxidative stress in the erythrocytes of diabetes-induced rats. Sprague-Dawley male rats were randomly assigned to one normal and three streptozotocin (STZ)-induced diabetic groups. 1be diabetic groups were fed a mulberry fruit-free diet (DM-group), 0.3% mulberry fruit diet (DM-F group) or 0.6% mulberry fruit diet (DM-2F group). Diabetes was induced with STZ after three weeks of the experimental diets. 1be rats were sacrificed 9 days later for examination of the antioxidative defense systems and oxidative stress in the erythrocytes. Means of cy-3-Ο-glucopyranoside, cy-3-Ο-rutinoside, rutin, isoquercitrin, quercetin, morin and dehydroquercetin contents were 230.45, 131.5, 142.5, 10.3, 5.8, 1.6 and 3.83mg per l00g dry weight, respectively, in the mulberry fruit. Mulberry fruit strengthened the antioxidative defense systems through increased activity of the antioxidant enzymes, such as glutathione peroxidase (GSH-px) and catalase (CAT), in the erythrocytes of the diabetes-induced rats. Accrdingly, mulberry fruit was found to reduce the accumulation of thiobarbituric acid reactive substance (WARS). Therefore, mulberry fruit was found to be excellent for strengthening the antioxidative defense system and reducing damaging oxidative substances in the erythrocytes of the diabetes-induced rats.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.10a
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• pp.71-74
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• 2003

Superoxide dismutase (SOD), one of the essential element of the antioxidant defense system, mainly removes $O^{-10}$ $_2$ and also prevents $O^{-10}$ $_2$ mediated reduction of iron and subsequent OH$^{-10}$ generation, which is highly toxic to the organism. Of these SOD enzymes, Cu, Zn-containing SOD (SODI) is an important component of the antioxidant defense system in eucaryotic cells. The SODI enzyme binds one copper and one zinc ion and displays the Greek Key $\beta$-barrel fuld. (omitted)

• Molecules and Cells
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• v.46 no.3
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• pp.133-141
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• 2023

Transcription factor NRF2 (NF-E2-related factor 2) is a master regulator of cellular responses against environmental stresses. NRF2 induces expression of detoxification and antioxidant enzymes and suppresses inductions of pro-inflammatory cytokine genes. KEAP1 (Kelch-like ECH-associated protein 1) is an adaptor subunit of CULLIN 3 (CUL3)-based E3 ubiquitin ligase. KEAP1 regulates the activity of NRF2 and acts as a sensor for oxidative and electrophilic stresses. NRF2 has been found to be activated in many types of cancers with poor prognosis. Therapeutic strategies to control NRF2-overeactivated cancers have been considered not only by targeting cancer cells with NRF2 inhibitors or NRF2 synthetic lethal chemicals, but also by targeting host defense with NRF2 inducers. Understanding precise molecular mechanisms how the KEAP1-NRF2 system senses and regulates the cellular response is critical to overcome intractable NRF2-activated cancers.

• Applied Biological Chemistry
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• v.34 no.2
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• pp.162-167
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• 1991

In an attempt to explore the mechanistic aspects of chilling injury in plants and their defensive measures against the low temperature stress, the time sequential measurements of pyruvate, superoxide radicals$(O_{\overline{2}})$ and antioxygenic enzymes during whole period of injury-inducing treatment were performed using mostly rice seedlings. Pyruvate was substantialy accumulated in leaf tissues during the exposure period to $5^{\circ}C$ of the seedlings ; the relative extent of the accumulation was increased with increasing time of the cold treatment. When the cold-treated plants were translocated to ambient temperature$({\sim}25^{\circ}C)$, the accumulation started to dissipate, concomitantly accompaning a remarkable increase in the $O_{\overline{2}}$ level of tissues. Superoxide dismutase(SOD) and catalase were also activated during post-chilling period, although they showed a considerable lag time for activation. In contrast, glutathione peroxidase, another antioxygenic enzyme in cells, was not activated at all by preceding cold treatment of plants. The uptake of exogenous $O_{\overline{2}}$ by the roots of rice seedlings resulted in increase in the activities of SOD and catalase in root tissues. The supply of $H_2O_2$ to plan st brought about the activation of catalase in situ, while failing to exert any effect on the activation state of glutathione peroxidase. The results obtained in this work suggest that pyruvate accumulation in cells is the direct cause of the overproduction of $O_{\overline{2}}$ and thereby other toxic activated oxygen species, and that SOD and catalase may play a crucial role in the protection of plant cells against active oxygen-mediated chilling injury.

• Archives of Pharmacal Research
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• v.27 no.8
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• pp.867-872
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• 2004

Oxidative stress due to reactive oxygen species (ROS) can cause oxidative damage to cells. Cells have a number of defense mechanisms to protect themselves from the toxicity of ROS. Mitochondria are especially important in the oxidative stress as ROS have been found to be constantly generated as an endogen threat. Mitochondrial defense depends mainly on super-oxide dismutase (SOD) and glutathione peroxidase (GPx), whereas microsomal defense depends on catalase (CAT), which is an enzyme abundant in microsomes. SOD removes superoxide anions by converting them to $H_2O$$_2$, which can be rapidly converted to water by CAT and GPx. Also, GPx converts hydroperoxide (ROOH) into oxidized-glutathione (GSSG). Ovariectomized (OVX) rats are used as an oxidative stress model. An ovariectomy increased the levels of MDA, one of the end-products in the lipid peroxidative process, and decreased levels of the antioxidative enzymes； SOD, CAT and GPx. However, Chondroitin sulfate (CS) decreased the levels of MDA, but increased the levels of SOD, CAT and GPx in a dose-depen-dent manner. Moreover, inflammation and cirrhosis of liver tissue in CS- treated rats were sig-nificantly decreased. These results suggest that CS might be a potential candidate as an anti oxidative reagent.

• Mycobiology
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• v.45 no.4
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• pp.409-420
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• 2017

Foliar sprays of three plant resistance inducers, including chitosan (CH), potassium sorbate (PS) ($C_6H_7kO_2$), and potassium bicarbonates (PB) ($KHCO_3$), were used for resistance inducing against Erysiphe cichoracearum DC (powdery mildew) infecting okra plants. Experiments under green house and field conditions showed that, the powdery mildew disease severity was significantly reduced with all tested treatments of CH, PS, and PB in comparison with untreated control. CH at 0.5% and 0.75% (w/v) plus PS at 1.0% and 2.0% and/or PB at 2.0% or 3.0% recorded as the most effective treatments. Moreover, the highest values of vegetative studies and yield were observed with such treatments. CH and potassium salts treatments reflected many compounds of defense singles which leading to the activation power defense system in okra plant. The highest records of reduction in powdery mildew were accompanied with increasing in total phenolic, protein content and increased the activity of polyphenol oxidase, peroxidase, chitinase, and ${\beta}$-1,3-glucanase in okra plants. Meanwhile, single treatments of CH, PS, and PB at high concentration (0.75%, 2.0%, and/or 3.0%) caused considerable effects. Therefore, application of CH and potassium salts as natural and chemical inducers by foliar methods can be used to control of powdery mildew disease at early stages of growth and led to a maximum fruit yield in okra plants.

• The Plant Pathology Journal
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• v.37 no.3
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• pp.205-214
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• 2021

The use of the supernatant from a Bacillus subtilis culture mixed with sodium bicarbonate was explored as a means of controlling stem brown spot disease in dragon fruit plants. In in vitro experiments, the B. subtilis supernatant used with sodium bicarbonate showed a strong inhibition effect on the growth of the fungus, Neoscytalidium dimidiatum, the agent causing stem brown spot disease and was notably effective in preventing fungal invasion of dragon fruit plant. This combination not only directly suppressed the growth of N. dimidiatum, but also indirectly affected the development of the disease by eliciting the dragon-fruit plant's defense response. Substantial levels of the pathogenesis-related proteins, chitinase and glucanase, and the phenylpropanoid biosynthetic pathway enzymes, peroxidase and phenyl alanine ammonia-lyase, were triggered. Significant lignin deposition was also detected in treated cladodes of injured dragon fruit plants in in vivo experiments. In summary, B. subtilis supernatant combined with sodium bicarbonate protected dragon fruit plant loss through stem brown spot disease during plant development in the field through pathogenic fungal inhibition and the induction of defense response mechanisms.

• Journal of Microbiology and Biotechnology
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• v.21 no.4
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• pp.379-386
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• 2011

The objective of this work was to investigate the ability of the plant growth-promoting rhizobacterium Pseudomonas aureofaciens 63-28 to induce plant defense systems, including defense-related enzyme levels and expression of defense-related isoenzymes, and isoflavone production, leading to improved resistance to the phytopathogen Rhizoctonia solani AG-4 in soybean seedlings. Seven-day-old soybean seedlings were inoculated with P. aureofaciens 63-28, R. solani AG-4, or P. aureofaciens 63-28 plus R. solani AG-4 (P+R), or not inoculated (control). After 7 days of incubation, roots treated with R. solani AG-4 had obvious damping-off symptoms, but P+R-treated soybean plants had less disease development, indicating suppression of R. solani AG-4 in soybean seedlings. Superoxide dismutase (SOD) and catalase (CAT) activities of R. solani AG-4-treated roots increased by 24.6% and 54.0%, respectively, compared with control roots. Ascorbate peroxidase (APX) and phenylalanine ammonia lyase (PAL) activities of R. solani AG-4-treated roots were increased by 75.1% and 23.6%, respectively. Polyphenol oxidase (PPO) activity in soybean roots challenged with P. aureofaciens 63-28 and P+R increased by 25.0% and 11.6%, respectively. Mn-SOD (S1 band on gel) and Fe-SOD (S2) were strongly induced in P+R-treated roots, whereas one CAT (C1) and one APX (A3) were strongly induced in R. solani AG-4- treated roots. The total isoflavone concentration in P+Rtreated shoots was 27.2% greater than the control treatment. The isoflavone yield of R. solani AG-4-treated shoots was 60.9% less than the control.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.1
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• pp.52-59
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• 2007

The present study was designed to assess whether dietary inorganic and organic selenium (Se) could affect antioxidant enzymes, including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and glutathione-S-transferase (GST), and the level of malondialdehyde (MDA), a marker of lipid peroxidation, in the intestine, serum, liver, and gastrocnemius muscle of Korean native goats. A total of eighteen Korean native goats was allotted into three dietary groups, consisting of basal diet (CON), or basal diet with either 0.25 ppm inorganic (IOSEL) or 0.25 ppm organic Se (ORSEL), and fed the corresponding diets for 5 wks. Growth performance, including body weight and total gain, and blood biochemical profiles, including GSH-Px, were not significantly different between the three dietary groups. Also, the specific activities of SOD, GSH-Px, and GST, and the level of MDA in the intestinal mucosa and liver from goats were not substantially affected by either inorganic Se or organic Se. However, goats fed the diet containing organic Se showed a significant increase in GSH-Px and GST activities in the gastrocnemius muscle compared with those fed the basal diet. In conclusion, increased muscle GSH-Px and GST activities suggest that dietary organic Se may affect, at least in part, the antioxidant defense system in muscle of Korean native goats under the conditions of our feeding regimen.