• Horticultural Science & Technology
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• v.33 no.5
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• pp.625-632
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• 2015

Drought is a severe abiotic stress that affects global crop production. A drought model was created for 'Toyonoka' Fragaria ${\times}$ ananassa, and the effects of drought stress on contents of proline, sugars, and antioxidant enzyme activities were investigated. Strawberry transplants with identical growth were chosen for the experiments and the randomized design included four replications (10 plants per block). The experimental sets differed in the moisture level of the culture medium relative to the range of moisture content as follows: control, 70-85%; mild drought stress, 50-60%; moderate drought stress, 40-50%; and severe drought stress, 30-40%. Drought stress was imposed by limiting irrigation. Plants were sampled and physiological parameters w ere measured on 0, 2, 4, 6, 8, and 10 days after the commencement of droughts tress. The water potential of strawberry leaves decreased in the plants under mild, moderate, and severe stress during the course of the water stress treatment and exhibited a significant difference from the control. Strawberry leaves subjected to drought stress had higher accumulation of proline, sugars, and malondialdehyde, and higher activities of superoxide dismutase, peroxidase, and catalase than leaves of control plants. Malondialdehyde levels increased in parallel with the severity and duration of drought stress. By contrast, antioxidant enzyme activity displayed dynamic responses to drought stress, first increasing and subsequently decreasing as the severity and duration of drought stress increased. These results suggest that strawberry plants respond to drought stress by altering the activities of antioxidant enzymes and the levels of osmotically active metabolites. These biochemical response changes may confer adaptation to drought stress and improve the capacity of plants to withstand water-deficit conditions.

• Animal cells and systems
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• v.8
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• pp.23-23
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• 2004

• Journal of Applied Biological Chemistry
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• v.64 no.1
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• pp.39-48
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• 2021

Droughts are one of the abiotic stresses that hinders the growth and productivity of crop plants. Coping with abiotic stress is necessary to understand the molecular regulatory networks that makes plants respond to adverse environmental conditions. In our experiment to find a combination that can cope with abiotic stress (respond to drought), we screened 5 stress-inducible promoters that are expressed only under stress conditions. This founded 36 cis-elements in stress-inducible promoters. With the result we designed 2 synthetic promoters (BL1, BL2) for fine-controlled regulation by assembling cis-elements from the native promoters, which are expressed only under stress caused by droughts. Analysis of the transgenic plant (BL1-GUS, BL2-GUS) showed that the synthetic promoters increased the expression of β-glucuronidase (GUS) in transgenic plants under desiccation. Also in the transient activation assay demonstrated that synthetic promoters induced the co-transformation of effector DREB1A and DREB2C. These results expect that the synthetic promoter with a combination of drought-specific elements can be used to respond to various abiotic stress and is resistant to stress without causing growth retardation.

• The Plant Pathology Journal
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• v.31 no.4
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• pp.323-333
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• 2015

As sessile organisms, plants are exposed to persistently changing stresses and have to be able to interpret and respond to them. The stresses, drought, salinity, chemicals, cold and hot temperatures, and various pathogen attacks have interconnected effects on plants, resulting in the disruption of protein homeostasis. Maintenance of proteins in their functional native conformations and preventing aggregation of non-native proteins are important for cell survival under stress. Heat shock proteins (HSPs) functioning as molecular chaperones are the key components responsible for protein folding, assembly, translocation, and degradation under stress conditions and in many normal cellular processes. Plants respond to pathogen invasion using two different innate immune responses mediated by pattern recognition receptors (PRRs) or resistance (R) proteins. HSPs play an indispensable role as molecular chaperones in the quality control of plasma membrane-resident PRRs and intracellular R proteins against potential invaders. Here, we specifically discuss the functional involvement of cytosolic and endoplasmic reticulum (ER) HSPs/chaperones in plant immunity to obtain an integrated understanding of the immune responses in plant cells.

• Journal of the Korea Safety Management & Science
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• v.12 no.4
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• pp.31-39
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• 2010

The purpose of this study was to examine the effects of stress response on safety behavior and to explore moderating effect of safety climate between stress response and safety behavior. 224 workers were asked to respond to the questionnaires that measured various demographic variables, stress response, safety climates and safety behaviors. A hierarchical regression was conducted to identify variables that had significant relationships with safety behavior and to examine moderating effect of safety climate between stress response and safety behavior. Results indicated that the depression response significantly predicted safety behavior. It was found that the safety climate was also a significant predictor for safety behavior. In addition, safety climate had a moderating effect on the relation between depression and anger responses and safety behavior.

• Human Ecology Research
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• v.57 no.2
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• pp.295-305
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• 2019

This study examined the effects of social comparison orientation and stress coping styles on job-seeking stress experienced by university students. The participants of this study were 324 junior and senior students (151 males and 173 females) from six universities located in Seoul who were preparing for employment. They were asked to respond to a written questionnaire to measure research variables for the Job-Seeking Stress Scale, the Social Comparison Orientation Scale, and the Ways of Coping Checklist. The data were analyzed by means of descriptive statistics and a hierarchical multiple regression. The major findings of this study were as follows. First, social comparison orientation had a positive effect on job-seeking stress of university students, revealing that students with a high level of social comparison orientation were more likely to experience job-seeking stress. Second, both emotion-alleviation coping style and wishful thinking coping style increased level of job-seeking stress. In addition, problem-focused coping style had a negative influence on job-seeking stress, whereas social support seeking coping style had no significant effect on it. The results suggested that it would be possible to reduce job-seeking stress of university students by changing either social comparison or stress coping style.

• Human Ecology Research
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• v.52 no.3
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• pp.313-324
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• 2014

This study investigated the effects of acculturative stress and resilience on the depression of university students from North Korea, and examined the moderating effect of resilience on the relation between acculturative stress and depression. The participants of this study were 116 university students from North Korea (53 males and 63 females) aged between 20 and 35 years. The participants were asked to respond either to a written questionnaire or to an online survey system designed to measure research variables. The data were analyzed by using descriptive statistics and a hierarchical regression. The moderating effect of resilience was examined by means of a hierarchical regression. The major findings were as follows: first, an increase in the level of acculturative stress increased that of depression, whereas an increase in the level of resilience decreased that of depression. Second, the moderating effect of resilience on the relation between acculturative stress and depression was statistically significant. That is, the negative influence of acculturative stress on depression was greater when the level of resilience was low, compared to when it was high. In summary, both acculturative stress and resilience had significant effects on the depression of university students from North Korea. Moreover, resilience buffered the detrimental effect of acculturative stress on their depression.

• BMB Reports
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• v.33 no.4
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• pp.344-348
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• 2000

The logarithmically growing Schizosaccharomyces pombe cells were subjected to high heat ($40^{\circ}C$), hydrogen peroxide, and heavy metals such as mercuric chloride and cadmium chloride. Then, the stress responses of catalase, glutathione S-transferase and thioltransferase were investigated. The high heat and cadmium chloride enhanced the catalase activity. The glutathione S-transferase activity of S. pombe cells was increased after treatments with heavy metals. The thioltransferase activity of S. pombe cells was completely abolished by mercuric chloride. Hydrogen peroxide caused no effect on the activities of glutathione S-transferase and thioltransferase. These results suggest that the response of S. pombe cells against oxidative stress is very complicated.

• Molecules and Cells
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• v.37 no.6
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• pp.435-440
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• 2014

Hemodynamic shear stress, the frictional force acting on vascular endothelial cells, is crucial for endothelial homeostasis under normal physiological conditions. When discussing blood flow effects on various forms of endothelial (dys)function, one considers two flow patterns: steady laminar flow and disturbed flow because endothelial cells respond differently to these flow types both in vivo and in vitro. Laminar flow which exerts steady laminar shear stress is atheroprotective while disturbed flow creates an atheroprone environment. Emerging evidence has provided new insights into the cellular mechanisms of flowdependent regulation of vascular function that leads to cardiovascular events such as atherosclerosis, atherothrombosis, and myocardial infarction. In order to study effects of shear stress and different types of flow, various models have been used. In this review, we will summarize our current views on how disturbed flow-mediated signaling pathways are involved in the development of atherosclerosis.

• Journal of Microbiology and Biotechnology
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• v.25 no.1
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• pp.50-56
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• 2015

During pretreatment of lignocellulosic biomass, a variety of fermentation inhibitors, including acetic acid and vanillin, are released. Using DNA microarray analysis, this study explored genes of the budding yeast Saccharomyces cerevisiae that respond to vanillin-induced stress. The expression of 273 genes was upregulated and that of 205 genes was downregulated under vanillin stress. Significantly induced genes included MCH2, SNG1, GPH1, and TMA10, whereas NOP2, UTP18, FUR1, and SPR1 were down regulated. Sequence analysis of the 5'-flanking region of upregulated genes suggested that vanillin might regulate gene expression in a stress response element (STRE)-dependent manner, in addition to a pathway that involved the transcription factor Yap1p. Retardation in the cell growth of mutant strains indicated that MCH2, SNG1, and GPH1 are intimately involved in vanillin stress response. Deletion of the genes whose expression levels were decreased under vanillin stress did not result in a notable change in S. cerevisiae growth under vanillin stress. This study will provide the basis for a better understanding of the stress response of the yeast S. cerevisiae to fermentation inhibitors.