• The Korean Journal of Food And Nutrition
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• v.11 no.1
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• pp.107-113
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• 1998

This experiment has conducted to evaluate whether single injection of red ginseng extract including 50% ethanol extract, crude saponin, and lipid soluble fraction can induce oxidative burst of mouse peritoneal macrophages with use of fluorescence spectrophotometer. To optimize conditions of fluorescent spectrophotometry, concentrations of DCFH-DA(2', 7' -dichlorofluorescin diacetate) was 1.6 ${\mu}{\textrm}{m}$ and control oxidative burst by Zymosan A and PMA(phorbol myristate acetate) were 100$\mu\textrm{g}$, 250ng, respectively. Though in vitro macrophages failed to induce increment of H2O2 production, but 50% ethanol extract group induced significant enhancement of H2O2 production when zymosan A triggered oxidative burst. On the other hand, lipid soluble fraction enhanced significantly H2O2 production than that of control group. These findings consisted with the other reports which showed ginsenosides inhibited nitric oxide production and lipid soluble fraction activated colony stimulating factor(granulocyte - monocyte) activity in bone marrow stem cells. As is well known, lipid soluble fraction contains phenol compound, polyacetylene compound and alkaloids. Further study would unravel which component of it can induce H2O2 production of macrophages. Key words : Red ginseng(Panax ginseng), H2O2 production, macrophages.

• ALGAE
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• v.27 no.1
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• pp.21-32
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• 2012

We report an oxidative burst triggered by prostaglandin $A_2(PGA_2)$ in the brown algal kelp Laminaria digitata, constituting the first such discovery in an alga and the second finding of an oxidative burst triggered by a prostaglandin in a living organism. The response is more powerful than the oxidative burst triggered by most other chemical elicitors in Laminaria. Also, it is dose-dependent and cannot be inhibited by diphenylene iodonium, suggesting that another source than NAD(P)H oxidase is operational in the production of reactive oxygen species. Despite the very strong oxidative response, rather few effects at other levels of signal transduction pathways could be identified. $PGA_2$ does not increase lipolysis (free fatty acids) in Laminaria, and only one oxylipin (15-hydroxyeicosatetraenoic acid; 15-HETE) was found to be upregulated in Laminaria. In a subsequent set of experiments in the genome model Ectocarpus siliculosus, none of 5 selected candidate genes, all established participants in various stress responses, showed any significant differences in their expression profiles.

• BLOOD RESEARCH
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• v.53 no.4
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• pp.299-306
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• 2018

Background IgG-mediated anaphylaxis occurs after infusion of certain monoclonal antibody-based therapeutics. New in vitro tests are urgently needed to diagnose such reactions. We investigated whether allergens trigger neutrophil oxidative burst (OB) and if neutrophil OB occurs due to allergen-specific IgG (sIgG). Methods Neutrophil OB was measured by dihydrorhodamine 123 flow cytometry using a leukocyte suspension spiked with a very small patch of the allergen crude extract, Dermatophagoides farinae (Der f). The mean fluorescence intensity ratio of stimulated to unstimulated samples was calculated as the neutrophil oxidative index (NOI). Results The Der f-specific NOI (Der f-sNOI) showed a time-dependent increase after Der f extract addition. At 15 min activation, higher Der f-sIgG levels were associated with lower Der f-sNOI values in 31 subjects (P<0.05). This inverse relationship occurs due to the initial blocking effect of free Der f-sIgG. Additionally, neutrophil OB was nearly absent (Der f-sNOI of -1) in two cases: a subject with undetectable Der f-sIgG levels and washed leukocyte suspensions deprived of Der f-sIgG. Conclusion Allergens can trigger neutrophil OB via preexisting allergen-sIgG. Neutrophil OB can be easily measured in a leukocyte suspension spiked with the allergen. This assay can be used to diagnose IgG-mediated anaphylaxis.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.64.1-64
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• 2003

Inoculation of primary pepper leaves with an avirulent strain of Xanthomonas campestris pv. vesicatoria induced systemic acquired resistance (SAR) in secondary leaves. This SAR response was accompanied by the systemic expression of defense-related genes, a systemic microoxidative burst generating H2O2, and the systemic induction of ion-leakage and callose deposition in the non-inoculated, secondary leaves. Some defense-related genes encoding PR-1, chitinase, peroxidase, PR10, thionin, defensin and zinc-finger protein were distiilctly induced in the systemic leaves. The systemically striking accumulation of H$_2$O$_2$and strong increase in peroxidase activity in pepper was suggested to contribute to the triggering of cell death In the systemic micro-HRs, leading to the induction of SAR. Treatment of non-inoculated, secondary leaves with diphenylene iodinium (DPI), an inhibitor of the oxidative burst, substantially reduced the induction of some defense-related genes and subsequently SAR.

• Journal of Veterinary Clinics
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• v.21 no.3
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• pp.236-242
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• 2004

1,2-benzopyrone can stimulate macrophages to increase the ability of phagocytosis. Peripheral blood polymorphonuclear cells (PMN) and macrophages destroy microbial organisms with reactive oxygen species (ROS), called oxidative burst activity (OBA). This study was undertaken to determine whether 1,2-benzopyrone affects the OBA on the phagocytic response of canine peripheral blood phagocytes. The OBA of phagocytes in the addition or absence of latex beads was analyzed by flow cytometry system using dihydrorhodamine 123 (DHR). The direct treatments of 1,2-benzopyrone have no effect on the OBA of peripheral blood mononuclear cells (PBMC), PMN and monocyte-rich cells regardless of addition of latex beads. When latex beads are added to PMN, the OBA of PMN was remarkably enhanced by culture supernatant from PBMC but not PMN treated with 1,2-benzopyrone. Similary, it was also enhanced by human recombinant (hr) $TNF-\alpha.$ However, when latex beads were not added to PMN, its OBA was not enhanced by culture supernatant from either PBMC or PMN treated with 1,2-benzopyrone. The OBA of latex beads-phagocytized PBMC and monocyte-rich cells was not enhanced by culture supernatant from either PBMC or PMN treated with 1,2-benzopyrone. These results strongly suggested that 1,2-benzopyrone has an immunoenhancing effect on the OBA of PMN when phagocytic response occurred only. This enhanced OBA may be mediated through active humoral substance(s), such as $TNF-\alpha,$ produced by PBMC stimulated with 1,2-benzopyrone.

• The Plant Pathology Journal
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• v.21 no.3
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• pp.283-287
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• 2005

Since the discovery of generation of $O_2^-$ in plant, many evidence for the oxidative burst (OXB) has been accumulated in various combinations of plant and pathogen or elicitor systems. $O_2^-$ generating system responsible for the OXB was coupled with oxidation of reduced nicotinamide adenine dinucleotide phosphate (NADPH) in microsomal fraction isolated from sliced aged potato tuber slices which were treated by hyphal wall components elicitor from Phytophthora infestans (HWC). We developed new assay method for quantitative measurement of oxygen radical $O_2^-$ by using electron spin resonance (ESR) analysis during elicitor­induced OXB on the surface of plant tissues. The ESR analysis using an $O_2^-$ trapper, Tiron (1,2-dihydroxy-3,5­benzenedisulfonic acid), provided a convenient assay for detecting only $O_2^-$ during elicitor-induced OXB producing various active oxygen species (AOS) on plant tissue surface. Tiron was oxidized to Tiron semiquinon radical by $O_2^-$. Quantity of the radical signal was measured by specific spectra on ESR spectroscopy. The level of $O_2^-$ was high in from surface of potato tuber tissue treated with hyphal cell wall elicitor (HWC) from Phytophthora infestans. There was no secondary OXB induction by $H_2O_2$ treatment in plant.

• Molecules and Cells
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• v.28 no.4
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• pp.321-329
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• 2009

Rapid production of nitric oxide (NO) and reactive oxygen species (ROS) has been implicated in the regulation of innate immunity in plants. A potato calcium-dependent protein kinase (StCDPK5) activates an NADPH oxidase StRBOHA to D by direct phosphorylation of N-terminal regions, and heterologous expression of StCDPK5 and StRBOHs in Nicotiana benthamiana results in oxidative burst. The transgenic potato plants that carry a constitutively active StCDPK5 driven by a pathogen-inducible promoter of the potato showed high resistance to late blight pathogen Phytophthora infestans accompanied by HR-like cell death and $H_2O_2$ accumulation in the attacked cells. In contrast, these plants showed high susceptibility to early blight necrotrophic pathogen Alternaria solani, suggesting that oxidative burst confers high resistance to biotrophic pathogen, but high susceptibility to necrotrophic pathogen. NO and ROS synergistically function in defense responses. Two MAPK cascades, MEK2-SIPK and cytokinesis-related MEK1-NTF6, are involved in the induction of NbRBOHB gene in N. benthamiana. On the other hand, NO burst is regulated by the MEK2-SIPK cascade. Conditional activation of SIPK in potato plants induces oxidative and NO bursts, and confers resistance to both biotrophic and necrotrophic pathogens, indicating the plants may have obtained during evolution the signaling pathway which regulates both NO and ROS production to adapt to wide-spectrum pathogens.

• Tuberculosis and Respiratory Diseases
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• v.48 no.2
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• pp.246-259
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• 2000

Background: As one of the etiologies of acute respiratory distress syndrome(ARDS), sepsis is one of the morbid causes of this cryptogenic malady. Even though many documents on the role of endotoxin(ETX) in the pathogenesis of ARDS have been issued, still the underlying mechanism associated with oxidative stress and activation of $PLA_2$ has been controversial. In the present study, the role of phospholipase $A_2(PLA_2)$ in the neutrophilic respiratory burst, which is presumed to cause acute lung injury during sepsis, was probed. Method: In glutathione-depleted Sprague-Dawley rats, lung leak, infiltration of neutrophils, $PLA_2$ activity and lipid peroxidation in the lung were measured after intratracheal instillation of endotoxin(delete). In addition, gamma glutamyl transferase(GGT) activity and the amount of pulmonary surfactant were measured. Morphologically, the changes in ultrastructure and cytochemical demonstration of oxidants were presented to confirm the neutrophilic oxidative stress and to elucidate the effects of $PLA_2$ activation on(delete) oxidative stress. Results: Instillation of ETX to glutathione-depleted rats intensified lung leak and lipid peroxidation when compared with non-glutathione depleted rats treated with the endotoxin. Moreover, oxidative stress was confirmed by the assay of GGT and malondialdehyde. Functionally, the depletion of glutathione altered the secretion of pulmonary surfactant from alveolar type II cells. Ultrastructurally and cytochemicaliy, oxidative stress was also confirmed after treatment of with ETX and diethylmaleate(DEM). Conclusion: The endotoxin-induced acute lung injury was mediated by oxidative stress, which in turn was provoked by the neutrophilic respiratory burst. The activation of $PLA_2$ in the lung seems to playa pivotal role in the oxidative stress of the lung.

• Molecules and Cells
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• v.39 no.5
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• pp.426-438
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• 2016

Plant disease resistance occurs as a hypersensitive response (HR) at the site of attempted pathogen invasion. This specific event is initiated in response to recognition of pathogen-associated molecular pattern (PAMP) and subsequent PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI). Both PTI and ETI mechanisms are tightly connected with reactive oxygen species (ROS) production and disease resistance that involves distinct biphasic ROS production as one of its pivotal plant immune responses. This unique oxidative burst is strongly dependent on the resistant cultivars because a monophasic ROS burst is a hallmark of the susceptible cultivars. However, the cause of the differential ROS burst remains unknown. In the study here, we revealed the plausible underlying mechanism of the differential ROS burst through functional understanding of the Magnaporthe oryzae (M. oryzae) AVR effector, AVR-Pii. We performed yeast two-hybrid (Y2H) screening using AVR-Pii as bait and isolated rice NADP-malic enzyme2 (Os-NADP-ME2) as the rice target protein. To our surprise, deletion of the rice Os-NADP-ME2 gene in a resistant rice cultivar disrupted innate immunity against the rice blast fungus. Malic enzyme activity and inhibition studies demonstrated that AVR-Pii proteins specifically inhibit in vitro NADP-ME activity. Overall, we demonstrate that rice blast fungus, M. oryzae attenuates the host ROS burst via AVR-Pii-mediated inhibition of Os-NADP-ME2, which is indispensable in ROS metabolism for the innate immunity of rice. This characterization of the regulation of the host oxidative burst will help to elucidate how the products of AVR genes function associated with virulence of the pathogen.

• Tuberculosis and Respiratory Diseases
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• v.51 no.6
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• pp.503-516
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• 2001

Background : The present study was carried out in association with neutrophilic respiratory burst in the lung in order to clarify the pathogenesis of acute respiratory distress syndrome(ARDS) following acute severe hemorrhage. Because oxidative stress has been suggested as one of the principal factors causing tissue injury, the role of free radicals from neutrophils was assessed in acute hemorrhage-induced lung injury. Method : In Sprague-Dawley rats, hemorrhagic shock was induced by withdrawing blood(20 ml/kg of B.W) for 5 min and the hypotensive state was sustained for 60 min. To determine the mechanism and role of oxidative stress associated with phospholipase A2(PLA2) by neutrophils, the level of lung leakage, pulmonary myeloperoxidase(MPO), and the pulmonary PLA2 were measured. In addition, the production of free radicals was assessed in isolated neutrophils by cytochemical electron microscopy in the lung. Results : In hypotensive shock-induced acute lung injury, the pulmonary MPO, the level of lung leakage and the production of free radicals were higher. The inhibition of PLA2 with mepacrine decreased the pulmonary MPO, level of lung leakage and the production of free radicals from neutrophils. Conclusion : A. neutrophilic respiratory burst is responsible for the oxidative stress causing acute lung injury followed by acute, severe hemorrhage. PLA2 activation is the principal cause of this oxidative stress.