• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.261-270
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• 2009

Oxidative stress is a major damaging factor for plants exposed to environmental stresses. In order to develop transgenic rice plants with enhanced tolerance to various environmental stresses, PsAPX1, the gene of ascorbate peroxidase isolated from Pisum sativum was expressed in chloroplast under the control of an oxidative stress inducible sweet potato peroxidase2 (SWPA2) promoter (referred to as PsAPX1 plants). PsAPX1 transgenic plants showed enhanced tolerance to various environmental stresses, such as 170 mM NaCl, UV-B, ozone, 20% PEG, and drought in compared with non-transgenic (NT) plants. These results suggest that chloroplast-targeted over-expression of PsAPX1 gene could be very useful strategy for developing transgenic rice plants with increased tolerance to environmental stresses.

• Microbiology and Biotechnology Letters
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• v.25 no.3
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• pp.240-247
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• 1997

Bacillary is the most common form of H. pylori observed during human infection. However, it is known that the morphology change of H. pylori from bacillary to coccoid can be occurred with a response to the environmental stresses such as the nutrient depletion, accumulation of toxic metabolites, pH alteration, and exposure to antimicrobial agents. The coccoid form of H. pylori, which is viable but non-culturable in vitro, seems to be the major cause of antibiotic resistancy and high reinfectability of H. pylori. In this regard, we studied the environmental factors that can induce the morphological change in vitro of H. pylori, and the change of fatty acid composition of plasma membrane. The morphological change from bacillary to coccoid could be observed with the depletion of nutrients, pH variation and reactive oxygen species added in the culture media. This morphologic conversion was paralleled by a dramatic decrease in unsaturated fatty acids and an increase in saturated fattv acids of plasma membrane. The change in composition of membrane fatty acid seems to be a kind of protection mechanism of H. pylori against these environmental stresses.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04a
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• pp.41-47
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• 2002

Adverse environmental conditions such as drought, high salt and cold/freezing are major factors that reduces crop productivity worldwide. According to a survey, $50-80\%$ of the maximum potential yield is lost by these 'environmental or abiotic stresses', which is approximately ten times higher than the loss by biotic stresses. Thus, Improving stress-tolerance of crop plants is an important way to improve agricultural productivity. In order to develop such stress-tolerant crop plants, we set out to identify key stress signaling components that can be used to develop commercially viable crop varieties with enhanced stress tolerance. Our primary focus so far has been on the identification of transcription factors that regulate stress responsive gene expression, especially those involved in ABA-mediated stress response. Be sessile, plants have the unique capability to adapt themselves to the abiotic stresses. This adaptive capability is largely dependent on the plant hormone abscisic acid (ABA), whose level increases under various stress conditions, triggering adaptive response. Central to the response is ABA-regulated gene expression, which ultimately leads to physiological changes at the whole plant level. Thus, once identified, it would be possible to enhance stress tolerance of crop plants by manipulating the expression of the factors that mediate ABA-dependent stress response. Here, we present our work on the isolation and functional characterization of the transcription factors.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04b
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• pp.41-47
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• 2002

Adverse environmental conditions such as drought, high salt and cold/freezing are major factors that reduces crop productivity worldwide. According to a survey, 50-80% of the maximum potential yield is lost by these 'environmental or abiotic stresses', which is approximately ten times higher than the loss by biotic stresses. Thus, improving stress-tolerance of crop plants is an important way to improve agricultural productivity. In order to develop such stress-tolerant crop plants, we set out to identify key stress signaling components that can be used to develop commercially viable crop varieties with enhanced stress tolerance. Our primary focus so far has been on the identification of transcription factors that regulate stress responsive gene expression, especially those involved in ABA-mediated stress response. Be sessile, plants have the unique capability to adapt themselves to the abiotic stresses. This adaptive capability is largely dependent on the plant hormone abscisic acid (ABA), whose level increases under various stress conditions, triggering adaptive response. Central to the response is ABA-regulated gene expression, which ultimately leads to physiological changes at the whole plant level. Thus, once identified, it would be possible to enhance stress tolerance of crop plants by manipulating the expression of the factors that mediate ABA-dependent stress response. Here, we present our work on the isolation and functional characterization of the transcription factors.

• Journal of Plant Biotechnology
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• v.35 no.2
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• pp.95-100
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• 2008

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a main enzyme in the glycolytic pathway, is involved in cellular energy production and regarded as a housekeeping gene. Previously, cytosolic GAPDH was selected as the most significantly abundant gene in EST library of sweetpotato suspension cells. In this study, a full-length of cDNA clone (IbGAPDH) encoding GAPDH was isolated from suspension-cultured cells of sweetpotato (Ipomoea babatas), and its expression was investigated with a view to understanding the physiological function of GAPDH in relation to environmental stresses. IbGAPDH encoded a 36.9 kDa polypeptide consisting of 337 amino acids. When the deduced amino acid of IbGAPDH was compared with other higher plants, IbGAPDH showed high homology with cytosolic GAPDH. The mRNA level of IbGAPDH significantly increased under environmental stresses, such as $H_2O_2$, MV and cold treatments. Among them, the transcript level of IbGAPDH gene was the highest under cold stress. Further investigation of the transcription level under $10^{\circ}C$ or $15^{\circ}C$ was performed with different tissues of sweetpotato. The transcription of IbGAPDH was increased by cold stress with tissue-specificity, moreover, showed different patterns according to temperature.

• Journal of Plant Biotechnology
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• v.43 no.3
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• pp.281-292
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• 2016

Plants can recognize and respond in various ways to diverse environmental stresses, including pathogenic microorganisms, salt, drought, and low temperature. Salicylic acid (SA) is one phytohormone that plays important roles in the regulation of plant growth and development. Nonexpressor of pathogenesis-related genes 1 (NPR1) was originally identified as a core protein that could function as a transcriptional co-regulator and SA receptor during systemic acquired resistance (SAR), a plant immune response that could activate PR genes after pre-exposure of a pathogen. Although the function of NPR1 in plant defense response and the role of SA hormone in the regulation of plant physiological processes have been well characterized, the biological role of NPR1 in plant abiotic stress responses is largely unknown. In this review, we will summarize and discuss the current understanding of NPR1 function in response to plant environmental stresses.

• Earthquakes and Structures
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• v.20 no.2
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• pp.161-173
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• 2021

The structural behavior of a tensile fabric structure, known as hypar, is investigated. Seismic-induced stresses in the fabric and axial forces in masts and cables are obtained using accelerograms recorded at different regions of the world. Time-history analysis using each recording are performed for the hypar by using finite element simulation. It is found that while the seismic stresses in the fabric are not critical for design, the seismic tensile forces in cables and the seismic compressive forces in masts should not be disregarded by designers. This is important, because the seismic design is usually not considered so relevant, as compared for instance with wind design, for these types ofstructures. The most relevant findings of this study are: 1) dynamic axial forces can have an increase of up to twice the static loading when the TFS is subjected to seismic demands, 2) large peak ground accelerations seem to be the key parameter for significant seismic-induced axial forces, but not clear trend is found to relate such forces with earthquakes and site characteristics and, 3) the inclusion or exclusion of the form-finding in the analysis procedure importantly affects results ofseismic stresses in the fabric, but not in the frame.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2003.06a
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• pp.82-89
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• 2003

• Interaction and multiscale mechanics
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• v.1 no.1
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• pp.123-142
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• 2008

Current methodologies used for the inference of thin film stresses through curvature measurements are strictly restricted to stress and curvature states which are assumed to remain uniform over the entire film/substrate system. These methodologies have recently been extended to non-uniform stress and curvature states for the thin film subject to non-uniform, isotropic misfit strains. In this paper we study the same thin film/substrate system but subject to non-uniform, anisotropic misfit strains. The film stresses and system curvatures are both obtained in terms of the non-uniform, anisotropic misfit strains. For arbitrarily non-uniform, anisotropic misfit strains, it is shown that a direct relation between film stresses and system curvatures cannot be established. However, such a relation exists for uniform or linear anisotropic misfit strains, or for the average film stresses and average system curvatures when the anisotropic misfit strains are arbitrarily non-uniform.

• Steel and Composite Structures
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• v.18 no.3
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• pp.583-601
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• 2015

In the present study, the combined effects of thermal and mechanical loadings on the interlaminar shear stresses of both moderately thin and thick composite laminated beams are numerically analyzed. The finite element modelling of laminated composite beams and analysis of interlaminar stresses are performed using the commercially available software package MSC NASTRAN/PATRAN. The validity of the finite element analysis (FEA) is demonstrated by comparing the experimental test results obtained due to mechanical loadings under the influence of thermal environment with those derived using the present FEA. Various parametric studies are also performed to investigate the effect of thermal loading on interlaminar stresses generated in symmetric, anti-symmetric, asymmetric, unidirectional, cross-ply, and balanced composite laminated beams of different stacking sequences with identical mechanical loadings and various boundary conditions. It is shown that the elevated thermal environment lead to higher interlaminar shear stresses varying with the stacking sequence, length to thickness ratio, ply orientations under identical mechanical loading and boundary conditions of the composite laminated beams. It is realized that the magnitude of the interlaminar stresses along xz plane is always much higher than those of along yz plane irrespective of the ply-orientation, length to thickness ratios and boundary conditions of the composite laminated beams. It is also observed that the effect of thermal environment on the interlaminar shear stresses in carbon-epoxy fiber reinforced composite laminated beams are increasing in the order of symmetric cross-ply laminate, unidirectional laminate, asymmetric cross-ply laminate and anti-symmetric laminate. The interlaminar shear stresses are higher in thinner composite laminated beams compared to that in thicker composite laminated beams under all environmental temperatures irrespective of the laminate stacking sequence, ply-orientation and boundary conditions.