• Journal of Applied Biological Chemistry
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• 제43권4호
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• pp.211-217
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• 2000

Oxidative stress is implicated in a number of diseases, in ageing of organisms, and in damage to plants that have been exposed to freezing and thawing or water stress. From the perspective of yeast as a model eukaryotic system, this article reviews the systems that are involved in the cellular responses to exposure to reactive oxygen species (ROS) generated during aerobic growth of the organism. The discussion includes the defense systems involved, the ability of cells to adapt to ROS treatment, cell-division cycle delay and the systems regulating gene expression that are activated by oxidative stress.

• Genomics & Informatics
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• 제3권3호
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• pp.63-67
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• 2005

Adaptive responses to diverse microbial pathogens might be limited in relatively few types. Host cell responses to pathogens are believed to be patterned or stereotyped along with species or class. We tried to compose the host response to Mycoplasma in terms of cellular gene expression. Although gene expression profile of two host HeLa and 293 cells were quite different each other, 30 genes were differentially expressed by mycoplasma infection in both of HeLa and 293 cells. Six of them (PR48, MADH4, MKPX, CRK, RBM7, NEK3) were related to cell cycle or proliferation. Another category of genes like IL1 HY1, KLRF1, TNFSF14, GBP1 were host defense to elicit immune responses. With this set of genes, we establish the prediction model for mycoplasma contamination.

• IMMUNE NETWORK
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• 제9권2호
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• pp.46-52
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• 2009

Although tuberculosis poses a significant health threat to the global population, it is a challenge to develop new and effective therapeutic strategies. Nitric oxide (NO) and inducible NO synthase (iNOS) are important in innate immune responses to various intracellular bacterial infections, including mycobacterial infections. It is generally recognized that reactive nitrogen intermediates play an effective role in host defense mechanisms against tuberculosis. In a murine model of tuberculosis, NO plays a crucial role in antimycobacterial activity; however, it is controversial whether NO is critically involved in host defense against Mycobacterium tuberculosis in humans. Here, we review the roles of NO in host defense against murine and human tuberculosis. We also discuss the specific roles of NO in the central nervous system and lung epithelial cells during mycobacterial infection. A greater understanding of these defense mechanisms in human tuberculosis will aid in the development of new strategies for the treatment of disease.

• The Plant Pathology Journal
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• 제22권3호
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• pp.271-277
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• 2006

The interaction effects of ozone $(O_3)$ and anthracnose (Colletotrichum acutatum) disease were examined in green fruits and seedlings of pepper (Capsicum annuum). Pre-treatment with $(O_3)$ as a factor causing predisposition to the disease prior to infection was investigated in green fruits and stems using an $(O_3)$ concentration of 150 nL/L, which is easily reached in summer in Korea. $(O_3)$ treatment increased antioxidative responses in pepper foliar tissues, and defense against anthracnose was examined in fruits and stems. Anthracnose severity on stems of the $O_3-treated$, ozone-sensitive 'Dabotop' cultivar was always lower than that on untreated plants, but the difference was not always significant (p=0.147). Significantly lower anthracnose severity was found on $O_3-treated$ green 'Dabotop' fruits as compared to untreated green fruits in three of eight replicate experiments. In contrast, hypersensitive responses in 03treated seedlings were significantly accelerated compared to those in untreated seedlings by about 7.8 h (p<0.001). This confirmed previous evidence of increased transcription of plant defense genes with $(O_3)$ treatment. $(O_3)$ treatment significantly decreased chlorophyll concentrations in the leaves in four replicate experiments (p<0.01). $(O_3)$ increased hypersensitive responses in the leaves of pepper seedlings, but this increase did not contribute to the control of anthracnose severity on fruits. Antioxidant reactions to $(O_3)$ were limited to chlorosis and changes in hypersensitive responses in leaves.

• Journal of Microbiology and Biotechnology
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• 제18권2호
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• pp.270-282
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• 2008

The yeast Saccharomyces cerevisiae has defense mechanisms identical to higher eukaryotes. It offers the potential for genome-wide experimental approaches owing to its smaller genome size and the availability of the complete sequence. It therefore represents an ideal eukaryotic model for studying cellular redox control and oxidative stress responses. S. cerevisiae Yap1 is a well-known transcription factor that is required for $H_2O_2$-dependent stress responses. Yap1 is involved in various signaling pathways in an oxidative stress response. The Gpx3 (Orp1/PHGpx3) protein is one of the factors related to these signaling pathways. It plays the role of a transducer that transfers the hydroperoxide signal to Yap1. In this study, using extensive proteomic and bioinformatics analyses, the function of the Gpx3 protein in an adaptive response against oxidative stress was investigated in wild-type, gpx3-deletion mutant, and gpx3-deletion mutant overexpressing Gpx3 protein strains. We identified 30 proteins that are related to the Gpx3-dependent oxidative stress responses and 17 proteins that are changed in a Gpx3-dependent manner regardless of oxidative stress. As expected, $H_2O_2$-responsive Gpx3-dependent proteins include a number of antioxidants related with cell rescue and defense. In addition, they contain a variety of proteins related to energy and carbohydrate metabolism, transcription, and protein fate. Based upon the experimental results, it is suggested that Gpx3-dependent stress adaptive response includes the regulation of genes related to the capacity to detoxify oxidants and repair oxidative stress-induced damages affected by Yap1 as well as metabolism and protein fate independent from Yap1.

• IMMUNE NETWORK
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• 제11권5호
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• pp.245-252
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• 2011

Antimicrobial peptides/proteins are ancient and naturally-occurring antibiotics in innate immune responses in a variety of organisms. Additionally, these peptides have been recognized as important signaling molecules in regulation of both innate and adaptive immunity. During mycobacterial infection, antimicrobial peptides including cathelicidin, defensin, and hepcidin have antimicrobial activities against mycobacteria, making them promising candidates for future drug development. Additionally, antimicrobial peptides act as immunomodulators in infectious and inflammatory conditions. Multiple crucial functions of cathelicidins in antimycobacterial immune defense have been characterized not only in terms of direct killing of mycobacteria but also as innate immune regulators, i.e., in secretion of cytokines and chemokines, and mediating autophagy activation. Defensin families are also important during mycobacterial infection and contribute to antimycobacterial defense and inhibition of mycobacterial growth both in vitro and in vivo. Hepcidin, although its role in mycobacterial infection has not yet been characterized, exerts antimycobacterial effects in activated macrophages. The present review focuses on recent efforts to elucidate the roles of host defense peptides in innate immunity to mycobacteria.

• Toxicological Research
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• 제30권2호
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• pp.77-81
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• 2014

In contrast to animals, plants do not have a circulatory system as well as mobile immune cells that allow them to protect themselves against pathogens. Instead, plants exclusively depend on the innate immune system to defend against pathogens. As typically observed in the animal innate immunity, plant immune responses are composed of pathogen detection, defense signaling which includes transcriptional reprogramming, and secretion of antimicrobial compounds. Although knowledge on recognition and subsequent signaling of pathogen-derived molecules called elicitors is now expanding, the mechanisms of how these immune molecules are excreted are yet poorly understood. Therefore, current understandings of how plants secrete defense products especially via exocytosis will be discussed in this review.

• Journal of Ginseng Research
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• 제46권6호
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• pp.790-800
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• 2022

Background: Panax ginseng Meyer is one of the most valuable medicinal plants which is enriched in anti-microbe secondary metabolites and widely used in traditional medicine. Botrytis cinerea is a necrotrophic fungus that causes gray mold disease in a broad range of hosts. B. cinerea could overcome the ginseng defense and cause serious leaf and root diseases with unknown mechanism. Methods: We conducted simultaneous transcriptomic and metabolomic analysis of the host to investigate the defense response of ginseng affected by B. cinerea. The gene deletion and replacement were then performed to study the pathogenic gene in B. cinerea during ginseng - fungi interaction. Results: Upon B. cinerea infection, ginseng defense responses were switched from the activation to repression, thus the expression of many defense genes decreased and the biosynthesis of antifungal metabolites were reduced. Particularly, ginseng metabolites like kaempferol, quercetin and luteolin which could inhibit fungi growth were decreased after B. cinerea infection. B. cinerea quercetin dioxygenase (Qdo) involved in catalyzing flavonoids degradation and ∆BcQdo mutants showed increased substrates accumulation and reduced disease development. Conclusion: This work indicates the flavonoids play a role in ginseng defense and BcQdo involves in B. cinerea virulence towards the P. ginseng. B. cinerea promotes disease development in ginseng by suppressing of defense related genes expression and reduction of antifungal metabolites biosynthesis.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 1999년도 임시총회 및 추계 학술발표회
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• pp.39.2-39
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• 1999

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 1999년도 춘계학술발표논문집 논문집
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• pp.221-230
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• 1999

Automobile horn's psychoacoustic characteristic and significance as a anturalistic signal of danger makes it a valuable auditory stimulus to study such psychophysiological responses as startle, orienting and defense reactions. However, comparison and differentiation of physiological responses to commercially available horns is a complicated task due to small contrast of technical features of horns and influence of such processes as habituation on physiological outcome with increased number of auditory stimulation trials. In the study on 10 college students we performed comparative analysis of tonic and phasic reactivity of physiological responses mediated by autonomic nervous system in order to identify role of habituation and decrement of autonomic responsivity, as well as possibility o differentiate subjectively most and least preferred and subjectively more appropriate horns according to physiological manifestations. It was showed that electrodermal and cardiovascular reactivity have concurrent patterns of adaptation to repeated stimulation, namely skin conductance variables habituated, cardiac reactivity failed to show signs of habituation, while vascular component of response were facilitated demonstrating marked sensitization. Differentiation of Physiological responses to horns with respect to their subjective rating scores was possible, however electrodermal reactivity was effective only at the first block of trials, while phasic and tonic cardiovascular reactivity differentiate responses during whole course of experiment. There are discussed possible autonomic mechanisms involved in mediation of observed results.