• Journal of Life Science
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• v.18 no.3
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• pp.304-310
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• 2008

Heat shock protein 70 (HSP70) is known as molecular chaperone, the fundamental protein participating in various processes, from nascent protein synthesis to protection of proteins during abiotic stresses and developmental programs. However, their biological functions in plants are not yet well known. Here, NtHSP70-1 (AY372069), HSP70 of Nicotiana tabacum induced by heat stress was investigated. To analyze the protective role of NtHSP70-1, transgenic tobacco plants, which constitutively overexpressed NtHSP70-1 as well as contained either the vector alone or having NtHSP70-1 in the antisense orientation, were constructed. The altered NtHSP70-1 levels in plants were confirmed by western blotting and transgenic sense lines exhibited tolerance to heat stress. Seedlings with the constitutively expressed NtHSP70-1 grew as green or healthy plants after heat stress. In contrast, transgenic vector or antisense lines exhibited yellowing of leaves or some delay in growth, which finally led to death. Evaluation of chlorophyll contents of heat-shocked transgenic tobacco seedlings indicated that NtHSP70-1 contributes to thermotolerance by preventing chlorophyll synthesis in plants.

• Biomolecules & Therapeutics
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• v.26 no.6
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• pp.568-575
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• 2018

In order to discover lifespan-extending compounds made from natural resources, activity-guided fractionation of Zingiber officinale Roscoe (Zingiberaceae) ethanol extract was performed using the Caenorhabditis elegans (C. elegans) model system. The compound 6-gingerol was isolated from the most active ethyl acetate soluble fraction, and showed potent longevity-promoting activity. It also elevated the survival rate of worms against stressful environment including thermal, osmotic, and oxidative conditions. Additionally, 6-gingerol elevated the antioxidant enzyme activities of C. elegans, and showed a dose-depend reduction of intracellular reactive oxygen species (ROS) accumulation in worms. Further studies demonstrated that the increased stress tolerance of 6-gingerol-mediated worms could result from the promotion of stress resistance proteins such as heat shock protein (HSP-16.2) and superoxide dismutase (SOD-3). The lipofuscin levels in 6-gingerol treated intestinal worms were decreased in comparison to the control group. No significant 6-gingerol-related changes, including growth, food intake, reproduction, and movement were noted. These results suggest that 6-gingerol exerted longevity-promoting activities independently of these factors and could extend the human lifespan.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.3
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• pp.237-242
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• 2016

Copper (Cu) is a necessary microelement for plants. However, high concentrations of Cu are toxic to plants that change the regulation of several stress-induced proteins. In this study, an annealing control primer (ACP) based approach was used to identify differentially expressed Cu-induced genes in alfalfa leaves. Two-week-old alfalfa plants (Medicago sativa L.) were exposed to Cu for 6 h. Total RNAs were isolated from treated and control leaves followed by ACP-based PCR technique. Using GeneFishing ACPs, we obtained several genes those expression levels were induced by Cu. Finally, we identified several genes including UDP-glucuronic acid decarboxylase, transmembrane protein, small heat shock protein, C-type cytochrome biogenesis protein, mitochondrial 2-oxoglutarate, and trans-2,3-enoyl-CoA reductase in alfalfa leaves. These identified genes have putative functions in cellular processes such as cell wall structural rearrangements, transduction, stress tolerance, heme transport, carbon and nitrogen assimilation, and lipid biosynthesis. Response of Cu-induced genes and their identification in alfalfa would be useful for molecular breeding to improve alfalfa with tolerance to heavy metals.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.10a
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• pp.56-56
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• 1999

For advanced TFT-LCD manufacturing processes, dry etching of thin-film layers(a-Si, $SiN_x$, SID & gate electrodes, ITO etc.) is increasingly preferred instead of conventional wet etching processes. To dry etch Al gate electrode which is advantageous for reducing propagation delay time of scan signals, high etch rate, slope angle control, and etch uniformity are required. For the Al gate electrode, some metals such as Ti and Nd are added in Al to prevent hillocks during post-annealing processes in addition to gaining low-resistivity($<10u{\Omega}{\cdot}cm$), high performance to heat tolerance and corrosion tolerance of Al thin films. In the case of AI-Nd alloy films, however, low etch rate and poor selectivity over photoresist are remained as a problem. In this study, to enhance the etch rates together with etch uniformity of AI-Nd alloys, magnetized inductively coupled plasma(MICP) have been used instead of conventional ICP and the effects of various magnets and processes conditions have been studied. MICP was consisted of fourteen pairs of permanent magnets arranged along the inside of chamber wall and also a Helmholtz type axial electromagnets was located outside the chamber. Gas combinations of $Cl_2,{\;}BCl_3$, and HBr were used with pressures between 5mTorr and 30mTorr, rf-bias voltages from -50Vto -200V, and inductive powers from 400W to 800W. In the case of $Cl_2/BCl_3$ plasma chemistry, the etch rate of AI-Nd films and etch selectivity over photoresist increased with $BCl_3$ rich etch chemistries for both with and without the magnets. The highest etch rate of $1,000{\AA}/min$, however, could be obtained with the magnets(both the multi-dipole magnets and the electromagnets). Under an optimized electromagnetic strength, etch uniformity of less than 5% also could be obtained under the above conditions.

• Journal of Plant Biotechnology
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• v.43 no.3
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• pp.302-310
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• 2016

A study aimed at identifying putative drought responsive genes that confer tolerance to water stress deficit in tea plants was conducted in a 'rain-out shelter' using potted plants. Eighteen months old drought tolerant and susceptible tea cultivars were each separately exposed to water stress or control conditions of 18 or 34% soil moisture content, respectively, for three months. After the treatment period, leaves were harvested from each treatment for isolation of RNA and cDNA synthesis. The cDNA libraries were sequenced on Roche 454 high-throughput pyrosequencing platform to produce 232,853 reads. After quality control, the reads were assembled into 460 long transcripts (contigs). The annotated contigs showed similarity with proteins in the Arabidopsis thaliana proteome. Heat shock proteins (HSP70), superoxide dismutase (SOD), catalase (cat), peroxidase (PoX), calmodulinelike protein (Cam7) and galactinol synthase (Gols4) droughtrelated genes were shown to be regulated differently in tea plants exposed to water stress. HSP70 and SOD were highly expressed in the drought tolerant cultivar relative to the susceptible cultivar under drought conditions. The genes and pathways identified suggest efficient regulation leading to active adaptation as a basal defense response against water stress deficit by tea. The knowledge generated can be further utilized to better understand molecular mechanisms underlying stress tolerance in tea.

• Journal of Life Science
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• v.22 no.11
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• pp.1515-1522
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• 2012

The phytohormone abscisic acid (ABA) plays an important role in the adaptive response of plants to abiotic stresses. ABA also regulates many important processes, including seed dormancy, germination, inhibition of cell division, and stomatal closure. OsABF2 (Oryza sativa ABRE binding factor2) is one of the bZIP type transcription factors, which are involved in abiotic stress response and ABA signaling in rice. Expression of OsABF2 is induced by ABA and various stress treatments. Findings show that survival rates of OsABF2 over-expressing Arabidopsis lines were increased under drought, salt, and heat stress conditions. The germination ratio of OsABF2 over-expressing Arabidopsis lines was decreased in the presence of ABA. Results indicate that OsABF2 over-expressing Arabidopsis lines have enhanced abiotic stress tolerance and have increased ABA sensitivity.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.106.1-106.1
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• 2013

When strong static magnetic field is applied to the TMP, it is expected that the presence of the magnetic field might retard the velocity of the blades which results in the change of the pumping speed of the TMP. However, such effect of the magnetic field on the TMP has not been well characterized. Thus, under the strong magnetic field, monitoring pumping speed as well as generated heat, pressure, and vibration of the TMP may be an important issue to understand the magnetic field tolerance of the TMP and the development of magnetic shielding technique for the key components of the pump. For this purpose, magnetic field generation system to the vertical direction by a circular current source was firstly designed and suggested [K. Baik et al., 44th Annual Conf. KVS, 22(1), 153, (2012)]. In the current study, another magnetic field generation systems are presented to apply the magnetic field to the horizontal and radial directions by the rectangular current sources and the permanent magnets respectively. Such systems were made to generate at least 50 Gauss of magnetic field along the vertical direction and at least 25 Gauss of magnetic field along the horizontal or radial direction. Current study introduces the evaluation system of the magnetic field along the vertical, horizontal, and radial directions and presents the measured experimental results of the magnetic field when such systems are combined with the equipment where TMP will be installed.

• Food Engineering Progress
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• v.21 no.4
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• pp.403-408
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• 2017

Acetic acid bacteria strains were isolated from a variety of fermented foods and fallen fruits. Among them, the strain MAK88, whose acetic acid fermentation ability, acid-tolerance, and alcohol-tolerance were high, was selected and identified as Acetobacter orientalis. A seed culture of A. orientalis MAK88 was inoculated into onion juice, and the optimum conditions of acetic acid fermentation was investigated. The optimum initial concentration of ethanol in onion juice was 5% (v/v) and in that condition, acidity was 4.31% at 144 h of fermentation. The optimum initial concentration of acetic acid was 1% and the final acidity was 5.32%. The optimum fermentation temperature was determined to be $28^{\circ}C$. The most appropriate preparation method of onion juice was to heat the onion at $121^{\circ}C$ for 15 min and produce juice with pressure followed by filtering, and then sterilization at $121^{\circ}C$ for 15 min. Prepared onion juice was used for fermentation without dilution.

• Transactions of Materials Processing
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• v.31 no.2
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• pp.51-56
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• 2022

In this study, finite element analyses were performed by applying a stress ring and split die design to relieve the tensile stress acting on the die due to high surface pressure during warm-closed forging. The applied material was a yield-ratio-control-steel (YRCS). It was used without quenching or tempering after forging. In the case of stress rings design, the number of stress rings and the tolerance for shrink fit were different. Vertical and horizontal splits were applied for insert die split design. Case 5 die with three stress rings, 0.2 % shrink fit tolerance, and vertical split was selected as an effective die design for tensile stress reduction. Based on die stress reduction analyses, Case 5 die for warm-closed forging was produced and smooth forgeability was secured, making it possible to manufacture forging product of yoke with the required geometry. In addition, controlled cooling using warm forging heat was applied to secure mechanical properties of yokes. When oil cooling was used for direct controlled cooling after warm-closed forging, a relatively uniform Rockwell hardness distribution and high mechanical properties could be obtained.

• Journal of Microbiology and Biotechnology
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• v.33 no.11
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• pp.1420-1427
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• 2023

The forkhead domain genes are important for development and morphogenesis in fungi. Six forkhead genes fkhA-fkhF have been found in the genome of the model filamentous Ascomycete Aspergillus nidulans. To identify the fkh gene(s) associated with fungal development, we examined mRNA levels of these six genes and found that the level of fkhB and fkhD mRNA was significantly elevated during asexual development and in conidia. To investigate the roles of FkhB and FkhD, we generated fkhB and fkhD deletion mutants and complemented strains and investigated their phenotypes. The deletion of fkhB, but not fkhD, affected fungal growth and both sexual and asexual development. The fkhB deletion mutant exhibited decreased colony size with distinctly pigmented (reddish) asexual spores and a significantly lower number of conidia compared with these features in the wild type (WT), although the level of sterigmatocystin was unaffected by the absence of fkhB. Furthermore, the fkhB deletion mutant produced sexual fruiting bodies (cleistothecia) smaller than those of WT, implying that the fkhB gene is involved in both asexual and sexual development. In addition, fkhB deletion reduced fungal tolerance to heat stress and decreased trehalose accumulation in conidia. Overall, these results suggest that fkhB plays a key role in proper fungal growth, development, and conidial stress tolerance in A. nidulans.