• Journal of Microbiology and Biotechnology
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• v.21 no.4
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• pp.438-447
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• 2011

Deinococcus radiodurans is extremely resistant to various genotoxic conditions and chemicals. In this study, we characterized the effect of a sublethal concentration (100 ${\mu}M$) of cadmium (Cd) on D. radiodurans using a whole-genome DNA microarray. Time-course global gene expression profiling showed that 1,505 genes out of 3,116 total ORFs were differentially expressed more than 2-fold in response to Cd treatment for at least one timepoint. The majority of the upregulated genes are related to iron uptake, cysteine biosynthesis, protein disulfide stress, and various types of DNA repair systems. The enhanced upregulation of genes involved in cysteine biosynthesis and disulfide stress indicate that Cd has a high affinity for sulfur compounds. Provocation of iron deficiency and growth resumption of Cd-treated cells by iron supplementation also indicates that CdS forms in iron-sulfur-containing proteins such as the [Fe-S] cluster. Induction of base excision, mismatch, and recombinational repair systems indicates that various types of DNA damage, especially base excision, were enhanced by Cd. Exposure to sublethal Cd stress reduces the growth rate, and many of the downregulated genes are related to cell growth, including biosynthesis of cell membrane, translation, and transcription. The differential expression of 52 regulatory genes suggests a dynamic operation of complex regulatory networks by Cd-induced stress. These results demonstrate the effect of Cd exposure on D. radiodurans and how the related genes are expressed by this stress.

• Journal of Microbiology and Biotechnology
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• v.23 no.10
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• pp.1365-1371
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• 2013

The Streptomyces coelicolor wblA gene is known to play a negative role in both antibiotic biosynthesis and the expression of genes responding to oxidative stress. Recently, WhcA, a WblA ortholog protein, was confirmed to interact with dioxygenase-encoding SpiA ($\underline{s}$tress $\underline{p}$rotein $\underline{i}$nteracting with Whc$\underline{A}$) in Corynebacterium glutamicum. We describe here the identification of a SpiA ortholog SCO2553 protein ($SpiA_{sc}$) that interacts with WblA in S. coelicolor. Using heterologous expression in E. coli and in vitro pull-down assays, we show that WblA specifically binds $SpiA_{sc}$, and is influenced by oxidants such as diamide. These data indicate that the interaction between WblA and $SpiA_{sc}$ is not only specific but also modulated by the redox status of the cell. Moreover, a $spiA_{sc}$-disruption mutant exhibited a less sensitive response to the oxidative stress induced by diamide present in solid plate culture. Real-time RT-PCR analysis also showed that transcription levels of oxidative stress response genes (sodF, sodF2, and trxB) were higher in the $spiA_{sc}$-deletion mutant than in wild-type S. coelicolor. These results show that $SpiA_{sc}$ negatively regulates WblA during oxidative stress responses in S. coelicolor.

• BMB Reports
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• v.53 no.11
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• pp.576-581
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• 2020

Dimethylation of the histone H3 protein at lysine residue 9 (H3K9) is mediated by euchromatin histone methyltransferase II (EHMT2) and results in transcriptional repression of target genes. Recently, chemical inhibition of EHMT2 was shown to induce various physiological outcomes, including endoplasmic reticulum stress-associated genes transcription in cancer cells. To identify genes that are transcriptionally repressed by EHMT2 during apoptosis, and cell stress responses, we screened genes that are upregulated by BIX-01294, a chemical inhibitor of EHMT2. RNA sequencing analyses revealed 77 genes that were upregulated by BIX-01294 in all four hepatic cell carcinoma (HCC) cell lines. These included genes that have been implicated in apoptosis, the unfolded protein response (UPR), and others. Among these genes, the one encoding the stress-response protein Ras-related GTPase C (RRAGC) was upregulated in all BIX-01294-treated HCC cell lines. We confirmed the regulatory roles of EHMT2 in RRAGC expression in HCC cell lines using proteomic analyses, chromatin immune precipitation (ChIP) assay, and small guide RNA-mediated loss-of-function experiments. Upregulation of RRAGC was limited by the reactive oxygen species (ROS) scavenger N-acetyl cysteine (NAC), suggesting that ROS are involved in EHMT2-mediated transcriptional regulation of stress-response genes in HCC cells. Finally, combined treatment of cells with BIX-01294 and 5-Aza-cytidine induced greater upregulation of RRAGC protein expression. These findings suggest that EHMT2 suppresses expression of the RRAGC gene in a ROS-dependent manner and imply that EHMT2 is a key regulator of stress-responsive gene expression in liver cancer cells.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.294-301
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• 2005

Ground response analysis is one of the most important and most commonly encountered problems in geotechnical earthquake engineering. It is a prerequisite step for liquefaction assessment of saturated soil or the pseudo-static and dynamic analysis of geotechnical structures. A number of techniques have been developed for ground response analysis. In this study, ground response analyses were performed using the computer programs that are currently being used domestically. From these analyses, the analysis techniques applied to the programs were compared and analyzed. The results of ground response analyses were compared as follows: 1) 1-dimensional analysis vs. 2-dimensional analysis; 2) equivalent linear analysis vs. nonlinear analysis.

• Journal of Ocean Engineering and Technology
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• v.37 no.6
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• pp.273-281
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• 2023

Recently, offshore structures for eco-friendly energy, such as wind and solar power, have been developed to address the problem of insufficient land space; in the case of energy generation, they are designed on a considerable scale. Therefore, the scalability of offshore structures is crucial. The Korea Research Institute of Ships & Ocean Engineering (KRISO) developed multi-linked floating offshore structures composed of floating bodies and connection beams for floating photovoltaic systems. Large-scale floating photovoltaic systems are mainly designed in a manner that expands through the connection between modules and demonstrates a difference in structural response with connection conditions. A fluid-structure coupled analysis was performed for the multi-linked floating offshore structures. First, the wave load acting on the multi-linked offshore floating structures was calculated through wave load analysis for various wave load conditions. The response amplitude operators (RAOs) for the motions and structural response of the unit structure were calculated by performing finite element analysis. The effects of connection conditions were analyzed through comparative studies of RAOs and the response's maximum magnitude and occurrence location. Hence, comparing the cases of a hinge connection affecting heave and pitch motions and a fixed connection, the maximum bending stress of the structure decreased by approximately 2.5 times, while the mooring tension increased by approximately 20%, confirmed to be the largest change in bending stress and mooring tension compared to fixed connection. Therefore, the change in structural response according to connection condition makes it possible to design a higher structural safety of the structural member through the hinge connection in the construction of a large-scale multi-linked floating offshore structure for large-scale photovoltaic systems in which some unit structures are connected. However, considering the tension of the mooring line increases, a safety evaluation of the mooring line must be performed.

• Korean Journal of Psychosomatic Medicine
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• v.6 no.2
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• pp.126-135
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• 1998

The object of this study was to investigate the relationship between stress and the extent of coronary artery stenosis in 101 patients with coronary artery diseases. Global assessment of recent stress(GARS) scale and perceived stress response inventory were used to measure perception for stressors and stress responses. Biological variables such as the extent of coronary artery stenosis, the number of the affected lesions on coronary angiography, serum Low Density Lipoprotein(LDL)-cholesterol, High Density Lipoprotein(HDL)-cholesterol, and total cholesterol were measured in all the subjects. Scores of perceived stress related to changes in relationship and overall global scores on GARS scale had significantly positive correlation with the extent of coronary artery stenosis. On the other hand, scores of percieved stress related to changes in relationship and changes or no changes in routine had significantly positive correlation with the number of the lesions. Scores of perceived stress related to change or no change in routine also positively correlated with serum level of LDL-cholesterol and total cholesterol. In contrast, general somatic symptoms negatively correlated with the extent of coronary artery stenosis. Impulsive-aggressive behavior negatively correlated with the number of the lesions. However, impulsive-aggressive thinking positively correlated with LDL-cholesterol. The above results suggest that perception for stressors may negatively affect the extent of coronary artery stenosis, the number of the lesions, serum LDL-cholesterol and total cholesterol. However, some stress responses showed inconsistent effect on the above biological variables. Thus, strategies designed to modify perception for stressors and some stress responses are likely to help the patients minimize the extent of coronary artery stenosis and prevent the diseases.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.3
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• pp.77-86
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• 2018

Stress is the main source of a human error or can potentially contribute to it. Recently, the rate of accidents which is associated with human factors among the total aircraft accidents is showing a tendency of gradual increase. In order to prevent the accidents related to human factors, stress mitigation of the mission personnel is highly required. In this study, a 'stress cognitive alteration' technique, which is one of the stress relief methods, is applied to the Air Force pilots to verify if the technique is effective in reducing stress. The 'stress cognitive alteration' technique is comprised of two parts: a positive function of stress and a process to positively alter the physical, psychological response to stress. As a result of the application, it is found that this technique has an effect of reducing stress of the pilots under a relatively high level of stress.

• Plant Biotechnology Reports
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• v.5 no.3
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• pp.225-234
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• 2011

Arabidopsis mutants with T-DNA insertion in seven calmodulin genes (CAM) were used to determine the specific role of CAM in the tolerance of plants to oxidative stress induced by paraquat and hydrogen peroxide ($H_2O_2$) treatments. Arabidopsis calmodulin mutants (cam) were screened for seedling growth, seed germination, induced oxidative damage, and levels of ${\gamma}$-aminobutyric acid (GABA) shunt metabolites. Only the cam5-4 and cam6-1 mutants exhibited an increased sensitivity to paraquat and $H_2O_2$ during seed germination and seedling growth. In response to treatments with $3{\mu}M$ paraquat and 1 mM $H_2O_2$, only the cam5-4, cam6-1 mutants showed significant changes in malonaldehyde (MDA) levels in root and shoot tissues, with highly increased levels of MDA. In terms of the GABA shunt metabolites, GABA was significantly elevated in root and shoot tissues in response to the paraquat treatments in comparison to alanine and glutamate, while the levels of all shunt metabolites increased in root tissue but not in the shoot tissue following the $H_2O_2$ treatments. GABA, alanine and glutamate levels were significantly increased in root and shoot of the cam1, cam4, cam5-4, and cam6-1 mutants in response to paraquat (0.5, 1 and $3{\mu}M$), while they were increased only in the root tissue of the cam1, cam4, cam5-4, and cam6-1 mutants in response to $H_2O_2$ (200 and $500{\mu}M$, 1 mM). These data show that the cam5-4 and cam6-1 mutants were sensitive to the induced oxidative stress treatments in terms of seed germination, seedling growth, and oxidative damage. The accumulation of GABA shunt metabolites as a consequence of the induced oxidative stress treatments (paraquat and $H_2O_2$ treatments) suggests that the GABA shunt pathway and the accumulation of GABA metabolites may contribute in antioxidant machinery associated with reactive oxygen species and in the acquisition of tolerance in response to induced oxidative stress in Arabidopsis seedlings.

• Korean Journal of Environment and Ecology
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• v.32 no.6
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• pp.658-666
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• 2018

The purpose of this study is to verify the effects of yoga and meditation-focused forest healing programs on profiles of mood states and stress reactions of adults. We tested 17 adults who agreed to participate in the experiments that were conducted for 2 nights and 3 days between September 8 to 10, 2017 in the healing forest located at Hongcheon-gun, Gangwon-do. The test used the simplified version of the inventory for the profile of mood states (K-POMS-B: Korean version of Profile of Mood States-Brief) and the stress response inventory as the measuring tools. For data analysis, we examined the differences in the profile of mood states and stress response of subjects before and after participation in the program through the paired T-tests with the SPSS 24.0 program. The analysis of the impact of the yoga and meditation-focused forest healing program on the profile of mood states of the test subjects showed the statistically significant reduction of the total score of the profile of mood states. Although the vigor among sub-level inventories increased, it was not statistically significant. But the tension, depression, anger, fatigue, and confusion showed a statistically significant reduction. The analysis of the impact of the yoga and meditation-focused forest healing program on the stress response of the test subjects showed a statistically significant reduction. Among sub-level inventories, the tension, somatization, anger, depression, fatigue, and frustration showed a statistically significant reduction, but the aggressiveness did not. It is expected that the results of this study can be utilized in the future as reference data for clarifying the effects of yoga and meditation-focused forest healing programs.

• Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.179-184
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• 2009

Hemibarbus mylodon (Cypriniformes) is an endemic freshwater fish species in the Korean peninsula, for which urgent conservation efforts are needed. To understand their stress responses in relation to metal toxicity and thermal elevation, we performed a real-time RT-PCR-based expression assay of hepatic copper/zinc-superoxide dismutase (Cu/Zn-SOD), a key antioxidant enzyme, in response to experimental heavy metal exposure or heat treatment. The transcription of hepatic Cu/Zn-SOD was differentially modulated by acute exposure to Cu, cadmium (Cd), or Zn. Exposure to each metal at $5{\mu}M$ for 24 h revealed that Cu stimulated the mRNA expression of Cu/Zn-SOD to a greater extent than the other two heavy metals. The elevation in Cu/Zn-SOD transcripts in response to Cu exposure was dose-dependent (0.5 to $5{\mu}M$). Time course analysis of Cu/Zn-SOD expression in response to Cd exposure ($5{\mu}M$) revealed a transient pattern up to day 7. Exposure to thermal stress (an increase from 22 to $30^{\circ}C$ at a rate of $1^{\circ}C/h$ followed by $30^{\circ}C$ for 18 h) did not significantly alter SOD transcription, although heat shock protein 90 kDa (HSP90) transcription was positively correlated with an increase in temperature.