• The Plant Pathology Journal
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• v.40 no.3
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• pp.235-250
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• 2024

During the infection process, plant pathogenic fungi encounter plant-derived oxidative stress, and an appropriate response to this stress is crucial to their survival and establishment of the disease. Plant pathogenic fungi have evolved several mechanisms to eliminate oxidants from the external environment and maintain cellular redox homeostasis. When oxidative stress is perceived, various signaling transduction pathways are triggered and activate the downstream genes responsible for the oxidative stress response. Despite extensive research on antioxidant systems and their regulatory mechanisms in plant pathogenic fungi, the specific functions of individual antioxidants and their impacts on pathogenicity have not recently been systematically summarized. Therefore, our objective is to consolidate previous research on the antioxidant systems of plant pathogenic fungi. In this review, we explore the plant immune responses during fungal infection, with a focus on the generation and function of reactive oxygen species. Furthermore, we delve into the three antioxidant systems, summarizing their functions and regulatory mechanisms involved in oxidative stress response. This comprehensive review provides an integrated overview of the antioxidant mechanisms within plant pathogenic fungi, revealing how the oxidative stress response contributes to their pathogenicity.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.677-686
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• 2013

Edible canna is a productive starch source in some tropical and semitropical regions. In these regions, water deficit stress is one of factors that limit the crop yield. In the present study, we investigated seven physiological indexes and photosynthetic responses of three edible canna (Canna edulis Ker.) cultivars ('PLRF', 'Xingyu-1', and 'Xingyu-2') under 35 days drought stress. Our results indicated that drought treatment caused visible wilting symptoms in all cultivars, especially in 'Xingyu-1'. Coupled with the increase of wilting symptoms, relative water content (RWC) and chlorophyll content decreased progressively, malondialdehyde (MDA) content gradually increased, and key antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) activities increased first and then decreased in all three cultivars. The effect of water stress was more pronounced in 'Xingyu-1' than in 'PLRF' and 'Xingyu-2', and in lower leaves than in upper leaves. In addition, 35 days drought stress also significantly reduced the photosynthetic capacity. Consistent with antioxidant parameters, photosynthetic changes of 'Xingyu-2' were less than those of the other cultivars under water deficit stress. Drought stress caused a significant increase of water use efficiency (WUE) in 'Xingyu-2', but little in 'PLRF', and obvious decrease in 'Xingyu-1'. These results indicated that 'Xingyu-2' was more tolerant to drought stress than 'PLRF' and 'Xingyu-1' by maintaining lower lipid peroxidation and higher antioxidant enzyme activities.

• Journal of fish pathology
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• v.24 no.2
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• pp.141-152
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• 2011

Growth, oxidative stress and antioxidant capacity of Fucus serratus exposed to high doses of Cd were examined. Two sites in Southwest England (Restronguet Point and Bantham Quay) were selected since they had different histories of metal contamination. 1~10 mg Cd $L^{-1}$ were treated to Aquil medium for up to 14 days. Similar levels of lipid peroxidation but different values of relative growth rates, cupric ion reducing antioxidant capacity (CUPRAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging capacity indicated that F. serratus has population-dependent antioxidant strategies. F. serratus demonstrated cadmium resistance with no visual symptoms for 14 days and the population from the polluted area seemed to have more powerful antioxidant strategies. However Fucus from the conserved area also showed protective anti oxidative mechanism.

• CELLMED
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• v.4 no.4
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• pp.26.1-26.9
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• 2014

Reactive oxygen species are known to mediate various pathological conditions associated with malaria. In this study, the antioxidant potential of Clerodendrum violaceum leaf extracts, an indigenous antimalarial remedy, was evaluated. Total phenol, flavonoid, selenium, vitamins C and E contents of Clerodendrum violaceum leaf extracts were determined. The free radical scavenging activities of the extracts against DPPH, superoxide anion and hydrogen peroxide coupled with their reducing power were also evaluated in vitro. Moreover, responses of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) in a rodent malaria model to a 4-day administration of Clerodendrum violaceum leaf extracts were also evaluated. The methanolic extract was found to contain the highest amounts of antioxidant compounds/element and also demonstrated the highest free radical scavenging activity in vitro. The results showed a significant decrease (p < 0.05) in SOD and CAT activities with a concurrent significant (p < 0.05) increase in GPx and GR activities in both erythrocytes and liver of untreated Plasmodium berghei NK65-infected animals compared to the uninfected animals. The extracts were able to significantly increase (p < 0.05) SOD and CAT activities and significantly reduce (p < 0.05) GPx and GR activities in both the liver and erythrocytes compared to those observed in the untreated infected animals. The results suggest the augmentation of the antioxidant system as one of the possible mechanisms by which Clerodendrum violaceum extract ameliorates secondary effects of malaria infection, alongside its antiplasmodial effect in subjects.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.31-31
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• 2022

Plant-derived antioxidants are used as a healthy diet and are known to inhibit various human diseases. In this study, we investigated free radical scavenging and antioxidant activity of extracts from three plants (Ammannia multiflora, Ammannia coccinea and Salix gracilistyla) with the most DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity from 196 plant extracts inhabiting along Nakdong River in Republic of Korea. The three extracts also have strong total antioxidant activity. Moreover, the extracts inhibited hydrogen peroxide (H₂O₂)-induced reactive oxygen species production and depolarized mitochondrial membrane potential in RAW264.7 macrophages. In zebrafish larvae, 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) fluorescent intensity, induced by H₂O₂, was markedly reduced by the extracts of A. multiflora, A. coccinea and S. gracilistyla. Meanwhile, the extracts were upregulated Nrf2 and HO-1 expression, and an HO-1 inhibitor reversed the extract-induced oxidative responses both in vivo and in vitro. The data suggest that the extracts of A. multiflora, A. coccinea, and S. gracilistyla exert potential free radical scavenging and antioxidant capacities both in vivo and in vitro by activating the Nrf2/HO-1 signaling pathway.

• International Journal of Industrial Entomology and Biomaterials
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• v.40 no.1
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• pp.16-21
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• 2020

Humans use insects as food and traditional medicine for many years. Hemolymph is the circulating fluid of insects and is a key component of their immune system. However, limited information is available regarding hemolymph identification, development, and differentiation, as well as the related cellular immune responses. In a previous study, hemolymph extracts prepared from Bombyx mori larvae were found to exert anti-inflammatory effects. In this study, we aimed to identify and compare the antioxidant activity of immune-challenged and unchallenged B. mori hemolymph extracts in vitro. For this purpose, human epithelial Caco-2 cells were first exposed to oxidative stress and then treated with various concentrations and incubation times of either immune-challenged or unchallenged B. mori hemolymph extracts. Next, we determined the effect of treatment on the relative expression of GPX-1, SOD-1, and SOD-2 antioxidant marker genes. We found that the expression rates of the three marker genes were markedly higher at a immune-challenged hemolymph extract concentration of 80 ppm compared to those at other concentrations, and the antioxidant effects were enhanced after treatment for 48 hr. Thus, B. mori hemolymph extracts showed antioxidant activity within the limited time and dose. Especially, the immune-challenged B. mori hemolymph extracts showed higher the antioxidant activities than unchallenged one. The activity of silkworm hemolymph extracts could facilitate the development of new types of functional foods, feed additives, and biomaterials with antioxidant properties.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.368-368
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• 2005

• Proceedings of the Korean Society of Crop Science Conference
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• 2006.04a
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• pp.190-191
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• 2006

• Forest Science and Technology
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• v.14 no.4
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• pp.153-159
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• 2018

Seedlings of Pterocarpus indicus were grown in both well-watered and drought stress conditions in phytotron. Seedlings grown under well-watered and drought stress conditions were exposed to either combined or without ozone of 200 ppb for one month. First, the physiological responses to elevated ozone levels indicated a decreased biomass. The seedlings grown in arid soil and exposed to ozone showed less biomass than those grown in arid soil but not exposed to ozone. Moreover, all the seedlings except the well-watered and unexposed ones showed a significantly lower photosynthetic rate ($P_N$) over time. However, with the accumulation of ozone injuries, the antioxidant enzyme activities increased overall. In the study results, when exposed to ozone, the well-watered seedlings exhibited more antioxidative enzyme activity than did the seedlings grown in arid soil. Generally, P. indicus in arid soil suffered less damage from elevated ozone than did the well-watered plants.

• Molecular & Cellular Toxicology
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• v.5 no.4
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• pp.273-282
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• 2009

Cadmium (Cd) and tributyltin (TBT) are common contaminants of marine and freshwater ecosystems, and can induce the formation of reactive oxygen species (ROS). These ROS can, in turn, cause oxidative stress. In the present study, we investigated time-related effects of Cd (0.05 and 0.1 ppm) and TBT (5 and 10 ppb) treatment on antioxidant enzyme activity, i.e., the activity of superoxide dismutase (SOD) and catalase (CAT) in the gills and digestive glands of the ark shell, Scapharca broughtonii. In addition, hydrogen peroxide ($H_2O_2$) concentrations, lysozyme activity, and glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) levels were measured in the hemolymph. We found that Cd and TBT treatment significantly increased antioxidant enzyme mRNA expression and activity in the digestive glands and gills in a time-dependent manner. In response to the Cd and TBT treatments, antioxidant enzymes mRNA expression and activity increased up to day 5 in the digestive glands and then decreased by day 7. In the gills, antioxidant enzymes mRNA expression and activity increased up to day 3 and then decreased by day 5. Likewise, $H_2O_2$ concentrations significantly increased up to day 5 and then decreased by day 7. Finally, lysozyme activity decreased during the experimental period, whereas GOT and GPT levels were significantly increased in a time-dependent manner. These results suggest that antioxidant enzymes play an important role in decreasing ROS levels and oxidative stress in ark shells exposed to Cd and TBT.