• Title/Summary/Keyword: environmental stress response

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Upregulation of thiamine (vitamin B1) biosynthesis gene upon stress application in Anabaena sp. and Nannochloropsis oculata

  • Fern, Lee Li;Abidin, Aisamuddin Ardi Zainal;Yusof, Zetty Norhana Balia
    • Journal of Plant Biotechnology
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    • v.44 no.4
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    • pp.462-471
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    • 2017
  • Thiamine pyrophosphate (TPP), the active form of thiamine is a cofactor for enzymes involved in central metabolism pathways. However, it is also known to have a role as a stress signaling molecule in response to environmental changes. Anabaena sp. and N. oculata are microorganisms which are abundantly found in Malaysia's freshwater and marine ecosystem. However, not much studies have been done especially in regards to thiamine biosynthesis. This work aimed to amplify of gene transcripts coding for thiamine biosynthesis enzymes besides looking at the expression of thiamine biosynthesis genes upon stress application. Various stress inducers were applied to the cultures and RNA was extracted at different time points. The first two genes, ThiC and ThiG/Thi4 encoding enzymes of the pyrimidine and thiazole branch respectively in the thiamine biosynthesis pathway were identified and amplified. The expression of the genes were analysed via RT-PCR and the intensity of bands were analysed using ImageJ software. The results showed up to 4-fold increase in the expression of ThiC and ThiG gene transcript as compared to control sample in Anabaena sp. ThiC gene in N. oculata showed an expression of 6-fold higher as compared to control sample. In conclusion, stresses induced the expression of the gene coding for one of the most important enzymes in thiamine biosynthesis pathway. This is an agreement with the hypothesis that overexpression of thiamine is crucial in assisting plants to combat abiotic stresses.

Characterizing Salt Stress Response in a Rice Variety and Its Salt Tolerant Lines Derived from In Vitro Mutagenesis

  • Lee In Sok;Kim Dong Sub;Kang Si Yong;Wi Seung Gon;Jin Hua;Yun PiI-Yong;Lim Yong Pyo;Lee Young Il
    • Journal of Plant Biotechnology
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    • v.6 no.4
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    • pp.205-212
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    • 2004
  • The objectives were to compare the salt tolerance levels in the parental rice cultivar, Dongjinbyeo, and induced mutagenesis derived its lines for plant height, MDA, ATPase, POD, and 2-dimensional protein electrophoresis pattern in NaCl-containing hydroponic nutrient solutions. Rice plants isolated from a population of rice (Oryza sativa L. cv. Dongjinbyeo) mutation lines, which were generated in combination with in vitro selection and gamma-ray, exhibited salt tolerance. Line No. 18 had the longest plant, whereas NaCl-sensitive line (No. 25) had the shortest plant. The parent, and the sensitive line showed severe damage from salt stress. Tolerant lines (No. 18, 50) had a lower malonaldehyde (MDA) content than the sensitive one (Dongjinbyeo, No. 25) during salt stress. Several proteins showed significant quantitative variation through 2DE; phosphoribulokinase, peroxidase, oxygen evolving enhancer 1 and the $H^+-ATPase$, which are known to be involved in salt tolerance. The effect of salt on peroxidase and $H^+-ATPase$ activity in the seedlings of two groups with contrasting genotypes of rice was studied. A greater activity was recorded in the tolerant lines as compared to the sensitive ones (P<0.05, Duncan's test). The results indicate that salt tolerant lines expressed more salt stress-inducible proteins associated with salt tolerance than the sensitive lines during salt stress.

Effect of exercise and diet intervention on endoplasmic reticulum (ER) stress in rat skeletal muscle and adipose tissue (운동부하가 고지방식이 유도 비만흰쥐의 골격근 및 지방조직의 ER (Endoplasmic Reticulum)스트레스에 미치는 영향)

  • Kim, Gi Chool;Park, Kyung Sil;Kim, Hyun Kook;Kim, Ki Hoon
    • Journal of Nutrition and Health
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    • v.45 no.5
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    • pp.420-428
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    • 2012
  • The purpose of this study is to investigate the effects of eight weeks high fat intake and regular exercise in skeletal muscle and adipose tissue for Endoplasmic Reticulum (ER) stress in rats. This experiment involved 32 subjects (sprague-dawley rats) divided into four groups as follows: chow group (Chow, n = 8), chow and exercise group (Chow + EX, n = 8), high fat diet-induced hyperlipidemia group (HF, n = 8), and HF and exercise group (HF + EX, n = 8). As a result, there were significant decrease in body weight and abdominal fat, and blood lipid level was significantly improved by exercise for eight weeks (p < .05). There were variables changed about the skeletal muscle and ER stress in GRP78, XBP-1, ATF4, CHOP and JNK mRNA. There increased in mRNA factor by exercise, especially GRP78, and ATF4 mRNA were significantly increased in exercise (p < .05). However, there were increased in adipose tissue by exercise and there were significantly decreased in mRNA factor by high fat diet (p < .05). Consequently, this study suggests that the consistent exercise was more improved of obesity factor, such as dyslipidemia, hyperlipidemia, hyperglycemia, as well as body weight or abdominal fat. The response of ER stress in adipose tissue and skeletal muscle were more sensitive in exercise than high fat diet feed.

Metabolic profiling reveals an increase in stress-related metabolites in Arabidopsis thaliana exposed to honeybees

  • Baek, Seung-A;Kim, Kil Won;Kim, Ja Ock;Kim, Tae Jin;Ahn, Soon Kil;Choi, Jaehyuk;Kim, Jinho;Ahn, Jaegyoon;Kim, Jae Kwang
    • Journal of Applied Biological Chemistry
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    • v.64 no.2
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    • pp.141-151
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    • 2021
  • Insects affect crop harvest yield and quality, making plant response mechanisms to insect herbivores a heavily studied topic. However, analysis of plant responses to honeybees is rare. In this study, comprehensive metabolic profiling of Arabidopsis thaliana exposed to honeybees was performed to investigate which metabolites were changed by the insect. A total of 85 metabolites-including chlorophylls, carotenoids, glucosinolates, policosanols, tocopherols, phytosterols, β-amyrin, amino acids, organic acids, sugars, and starch-were identified using high performance liquid chromatography, gas chromatography-mass spectrometry, and gas chromatography-time-of-flight mass spectrometry. The metabolite profiling analysis of Arabidopsis exposed to honeybees showed higher levels of stress-related metabolites. The levels of glucosinolates (glucoraphanin, 4-methoxyglucobrassicin), policosanols (eicosanol, docosanol, tricosanol, tetracosanol), tocopherols (β-tocopherol, γ-tocopherol), putrescine, lysine, and sugars (arabinose, fructose, glucose, mannitol, mannose, raffinose) in Arabidopsis exposed to honeybees were higher than those in unexposed Arabidopsis. Glucosinolates act as defensive compounds against herbivores; policosanols are components of plant waxes; tocopherols act as an antioxidant; and putrescine, lysine, and sugars contribute to stress regulation. Our results suggest that Arabidopsis perceives honeybees as a stress and changes its metabolites to overcome the stress. This is the first step to determining how Arabidopsis reacts to exposure to honeybees.

Alteration of cellular events in tooth development by chemical chaperon, Tauroursodeoxycholic acid treatment

  • Lee, Eui-Seon;Aryal, Yam Prasad;Kim, Tae-Young;Pokharel, Elina;Kim, Harim;Sung, Shijin;Sohn, Wern-Joo;Lee, Youngkyun;An, Chang-Hyeon;Kim, Jae-Young
    • International Journal of Oral Biology
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    • v.45 no.4
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    • pp.190-196
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    • 2020
  • Several factors, including genetic and environmental insults, impede protein folding and secretion in the endoplasmic reticulum (ER). Accumulation of unfolded or mis-folded protein in the ER manifests as ER stress. To cope with this morbid condition of the ER, recent data has suggested that the intracellular event of an unfolded protein response plays a critical role in managing the secretory load and maintaining proteostasis in the ER. Tauroursodeoxycholic acid (TUDCA) is a chemical chaperone and hydrophilic bile acid that is known to inhibit apoptosis by attenuating ER stress. Numerous studies have revealed that TUDCA affects hepatic diseases, obesity, and inflammatory illnesses. Recently, molecular regulation of ER stress in tooth development, especially during the secretory stage, has been studied. Therefore, in this study, we examined the developmental role of ER stress regulation in tooth morphogenesis using in vitro organ cultivation methods with a chemical chaperone treatment, TUDCA. Altered cellular events including proliferation, apoptosis, and dentinogenesis were examined using immunostaining and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. In addition, altered localization patterns of the formation of hard tissue matrices related to molecules, including amelogenin and nestin, were examined to assess their morphological changes. Based on our findings, modulating the role of the chemical chaperone TUDCA in tooth morphogenesis, especially through the modulation of cellular proliferation and apoptosis, could be applied as a supporting data for tooth regeneration for future studies.

Nonlinear dynamic analysis of RC frames using cyclic moment-curvature relation

  • Kwak, Hyo-Gyoung;Kim, Sun-Pil;Kim, Ji-Eun
    • Structural Engineering and Mechanics
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    • v.17 no.3_4
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    • pp.357-378
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    • 2004
  • Nonlinear dynamic analysis of a reinforced concrete (RC) frame under earthquake loading is performed in this paper on the basis of a hysteretic moment-curvature relation. Unlike previous analytical moment-curvature relations which take into account the flexural deformation only with the perfect-bond assumption, by introducing an equivalent flexural stiffness, the proposed relation considers the rigid-body-motion due to anchorage slip at the fixed end, which accounts for more than 50% of the total deformation. The advantage of the proposed relation, compared with both the layered section approach and the multi-component model, may be the ease of its application to a complex structure composed of many elements and on the reduction in calculation time and memory space. Describing the structural response more exactly becomes possible through the use of curved unloading and reloading branches inferred from the stress-strain relation of steel and consideration of the pinching effect caused by axial force. Finally, the applicability of the proposed model to the nonlinear dynamic analysis of RC structures is established through correlation studies between analytical and experimental results.

Mechanistic Analysis of Geogrid Base Reinforcement in Flexible Pavements Considering Unbound Aggregate Quality

  • Kwon Jay-Hyun;Tutumluer Erol;Kim Min-Kwan
    • International Journal of Highway Engineering
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    • v.8 no.2 s.28
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    • pp.37-47
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    • 2006
  • The structural response and performance of a flexible pavement can be improved through the use of geogrids as base course reinforcement. Current ongoing research at the University of illinois has focused on the development of a geogrid base reinforcement mechanistic model for the analysis of reinforced pavements. This model is based on the finite element methodology and considers not only the nonlinear stress-dependent pavement foundation but also the isotropic and anisotropic behavior of base/subbase aggregates for predicting pavement critical responses. An axisymmetric finite element model was developed to employ a three-noded axisymmetric membrane element for modeling geogrid reinforcement. The soil/aggregate-geogrid interface was modeled by the three-noded membrane element and the neighboring six-noded no thickness interface elements. To validate the developed mechanistic model, the commercial finite element program $ABAQUS^{TM}$ was used to generate pavement responses as analysis results for simple cases with similar linear elastic material input properties. More sophisticated cases were then analyzed using the mechanistic model considering the nonlinear and anisotropic modulus property inputs in the base/subbase granular layers. This paper will describe the details of the developed mechanistic model and the effectiveness of geogrid reinforcement when used in different quality unbound aggregate base/subbase layers.

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The Possible Participation of the Mesophyll on Stomatal Opening

  • Lee, Joon-Sang
    • Korean Journal of Environmental Biology
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    • v.19 no.1
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    • pp.1-6
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    • 2001
  • Many researchers have been studied with guard cell protoplasts and detached epidermis as they think that properly stabilized protoplasts and detached epidermis retain many of the properties of intact guard cells. However, some studies have shown that stomata in detached epidermis behave differently, both quantitatively and qualitatively, from those in the intact leaf. Stomata in the intact leaf are very sensitive to environmental factors such as light, $CO_2$ and osmotic stress, but stomata in detached epidermis are less sensitive to these factors than those in the intact leaf. The clearest evidence to suggest the different response between detached epidermis and intact leaf obtained from the experiments with heavy metal, cadmium. 3-weeks old Commelina. communis was transferred to and grown in Hoagland solution in the presence or absence of 5 mM $Cd^{2+}$ for 4 days. The application of $Cd^{2+}$ showed about 70% inhibition of stomatal conductance when measured at various light intensity (100-1,000 $\mu$mole $m^{-2}s^{-1}). However, stomata in detached epidermis floated on an incubation medium containing 100 $\mu$M $Cd^{2+}$ opened to a degree of about 8.38 fm, but the stomata treated with no cadmium opened to 3.74 ${\mu}{\textrm}{m}$. These results were unexpected as the intact leaf grown in a Hoagland solution containing cadmium showed very negative physiological responses. These results showed that stomata in detached epidermis and in the intact leaf could respond reversely. Therefore, it is possible that we now misunderstand how stomata open in real natural condition.

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Crack mapping in RC members using distributed coaxial cable crack sensors: modeling and application

  • Greene, Gary Jr.;Belarbi, Abdeldjelil;Chen, Genda
    • Smart Structures and Systems
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    • v.1 no.4
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    • pp.385-404
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    • 2005
  • The paper presents a model to calculate reinforcement strain using measured crack width in members under applied tension, flexure, and/or shear stress. Crack mapping using a new type of distributed coaxial cable sensors for health monitoring of large-scale civil engineering infrastructure was recently proposed and developed by the authors. This paper shows the results and performance of such sensors mounted on near surface of two flexural beams and a large scale reinforced concrete box girder that was subjected to cyclic combined shear and torsion. The main objectives of this health monitoring study was to correlate the sensor's response to strain in the member, and show that magnitude of the signal's reflection coefficient is related to increases in applied load, repeated cycles, cracking, and reinforcement yielding. The effect of multiple adjacent cracks, and signal loss was also investigated. The results shown in this paper are an important step in using the sensors for crack mapping and determining reinforcement strain for in-situ structures.

Analysis of Response Change of Structure due to Tunnel Excavation Conditions in Sand Ground (모래지반에서 터널 굴착조건들을 반영한 상부 블록구조물의 거동변화 분석)

  • Son, Moorak
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.4
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    • pp.1541-1549
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    • 2013
  • This study investigates the response of structures to tunnelling-induced ground movements in sand ground, varying tunnel excavation condition (tunnel depth and diameter), tunnel construction condition (ground loss), ground condition (loose sand and dense sand). Four-story block-bearing structures have been used because the structueres can easily be characterized of the extent of dmages with crack size and distribution. Numerical parametric studies have been used to investigae of the response of structures to varying tunnelling conditions. Numerical analysis has been conducted using Discrete Element Method (DEM) to have real cracks when the shear and tensile stress exceed the maximum shear and tensile strength. The results of structure responses from various parametric studies have been integrated to consider tunnel excavation condition, tunnel construction condition, and ground condition and provided as a relationship chart. Using the chart, the response of structures to tunnelling can easily be evaluated in practice in sand ground.