• BMB Reports
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• v.42 no.7
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• pp.439-443
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• 2009

Dehydrins are group II, late embryogenesis abundant proteins that act putatively as chaperones in stressed plants. To elucidate the function of dehydrins in poplar, we isolated the $SK_2$-type dehydrin gene Podhn from Populus alba $\times$ P. tremula var. glandulosa suspension cells and analyzed its expression following treatments of abiotic stress, wounding and plant growth regulator. Sequence homology and phylogenetic analyses indicate Podhn encodes an acidic dehydrin (pI 5.14, 277 amino acids, predicted size 25.6 kDa) containing two lysine-rich "K-segments" and a 7-serine residue "S-segment", both characteristic of $SK_2$-type dehydrins. Southern blots show Podhn genes form a small gene family in poplar. Podhn was expressed in all tissues examined under unstressed conditions, but most strongly in cell suspensions (especially in the stationary phase). Drought, salt, cold and exogenous abscisic acid (ABA) treatments enhanced Podhn expression, while wounding and jasmonic acid caused its reduction. Therefore, Podhn might be involved in ABA or stress response.

• Journal of Microbiology and Biotechnology
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• v.20 no.7
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• pp.1156-1162
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• 2010

During ethanol fermentation, bacterial strains may encounter various stresses, such as ethanol and acid shock, which adversely affect cell viability and the production of ethanol. Therefore, ethanologenic strains that tolerate abiotic stresses are highly desirable. Bacteria of the genus Deinococcus are extremely resistant to ionizing radiation, ultraviolet light, and desiccation, and therefore constitute an important pool of extreme resistance genes. The irrE gene encodes a general switch responsible for the extreme radioresistance of D. radiodurans. Here, we present evidence that IrrE, acting as a global regulator, confers high stress tolerance to a Zymomonas mobilis strain. Expression of the gene protected Z. mobilis cells against ethanol, acid, osmotic, and thermal shocks. It also markedly improved cell viability, the expression levels and enzyme activities of pyruvate decarboxylase and alcohol dehydrogenase, and the production of ethanol under both ethanol and acid stresses. These data suggest that irrE is a potentially promising gene for improving the abiotic stress tolerance of ethanologenic bacterial strains.

• Journal of Environmental Science International
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• v.11 no.11
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• pp.1165-1172
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• 2002

The effects of salicylic acid(SA) and water deficit on growth and proline accumulation were investigated in cucumber(Cucurmis sativus L.) seedlings. Exogenous application of SA(100 $\mu$M-1 mM) led to a noticeable decrease in root and shoot growth, and dry weight of seedlings. Anatomical observation on leaf of cucumber revealed that the thickness of all leaf tissue components decreased in SA-treated plants. The effect was most pronounced on the width of the adaxial epidermis. In the separate effects of SA(0, 100, 500 and 1000 $\mu$M) and water deficit induced by PEG(0, 4.4, 7.0 and 9.6 %) on growth, the water deficit treatments had greater effects on growth traits than SA. Combinations of SA and PEG(SA+PEG) decreased shoot and root dry matter, and root length. Proline increased slightly in SA-treated seedlings, but exhibited a marked increase in water deficit application. Combinations of SA+PEG induced higher proline in both shoots and roots than SA stress alone. Shoots had higher proline than roots. Our data support a role of SA potentiating the osmotic stress response of germinating cucumber seedling.

• Journal of Aquaculture
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• v.20 no.4
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• pp.205-211
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• 2007

Stress-inducible proteins may function in part as molecular chaperones, protecting cells from damage due to various stresses and helping to maintain homeostasis. We examined the mRNA expression patterns of a 68-kDa heat shock protein (HSP68) and 78-kDa glucose-regulated protein (GRP78) in relation to physiological changes in Pacific oyster Crassostrea gigas under osmotic stress. Expression of HSP68 and GRP78 mRNA in the gill significantly increased until 48 h in a hypersaline environment (HRE) and 72 h in a hyposaline environment (HOE), and then decreased. Osmolality and the concentrations of $Na^+$, $Cl^-$, and $Ca^{2+}$ in the hemolymph of HRE oysters significantly increased until 72 h (the highest value) and then gradually decreased; in HOE oysters, these values significantly decreased until 72 h (the lowest value), and then increased. These results suggest that osmolality and $Na^+$, $Cl^-$, and $Ca^{2+}$ concentrations were stabilized by HSP68 and GRP78, and indicate that these two stress-induced proteins play an important role in regulating the metabolism and protecting the cells of the Pacific oysters exposed to salinity changes.

• Journal of Plant Biotechnology
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• v.39 no.3
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• pp.175-181
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• 2012

Drought and high salinity stresses often imposes adverse effects on crop yield. MYB transcription factors have been shown to be an important regulator in defense responses to these environmental stresses. In this study, we have cloned and characterized a soybean gene GmMYB184 (Glycine max MYB transcription factor 184). Deduced amino acid sequences of GmMYB184 show highest homology with that from Vitis vinifera legume plant (75%). Different expression patterns of GmMYB184 mRNA were observed subjected to drought, cold, high salinity stress and abscisic acid treatment, suggesting its role in the signaling events in the osmotic stress-related defense response. Subcellular localization studies demonstrated that the GFP-GmMYB184 fusion protein was localized in the nucleus. Using the yeast assay system, the C-terminal region of GmMYB184 was found to be essential for the transactivation activity. These results indicate that the GmMYB184 may play a role in abiotic stress tolerance in plant.

• Journal of Microbiology and Biotechnology
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• v.21 no.3
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• pp.277-283
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• 2011

Glyoxalase I catalyzes the conversion of methylglyoxal to S-D-lactoylglutathione in the presence of glutathione. The structural gene of glyoxalase I (GLO1) was cloned from an osmotolerant yeast, Candida magnoliae, which produces a functional sweetener, erythritol, from sucrose. DNA sequence analysis revealed that the uninterrupted open reading frame (ORF) of C. magnoliae GLO1 (CmGLO1) spans 945 bp, corresponding to 315 amino acid residues, and shares 45.2% amino acid sequence identity to Saccharomyces cerevisiae Glo1. The cloned ORF in a multicopy constitutive expression plasmid complemented the glo1 mutation of S. cerevisiae, confirming that it encodes Glo1 in C. magnoliae. The responses of CmGLO1 to environmental stresses were different from those of S. cerevisiae, which only responds to osmotic stress. An enzyme activity assay and reverse transcription polymerase chain reaction revealed that the expression of CmGLO1 is induced by stress inducers such as methylglyoxal, $H_2O_2$, KCl, and NaCl. The GenBank Accession No. for CmGLO1 is HM000001.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.5
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• pp.676-684
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• 2021

Euryhaline teleost have extraordinary ability to deal with a wide range of salinity changes. To study the seawater adaptability of rainbow trout Oncorhynchus mykiss (body weight 638±54 g, length 38.6±2 cm) to salinity increase fish were transferred from freshwater to 7, 14, 21, 28 and 32 psu and checked for mortality over 5 days. No mortality was observed in 0-32 psu. In fish transferred to 0-32 psu, blood osmolality was maintained within physiological range. The changes of serum enzyme activities (aspartate transaminase, AST and alanine transaminase, ALT) showed no significant level during experimental period. To explore the underlying molecular physiology of gill and kidney responsible for body fluid regulation, we measured mRNA expression of five genes, Na⁺/K⁺/2Cl^- cotransporter1 (NKCC1), aquaporin3 (AQP3), cystic fibrosis transmembrane conductance regulator (CFTR), glucocorticoid receptor (GR) and growth hormone receptor (GHR) in response to salt stress. Based on our result, rainbow trout could tolerate gradual transfer up to 32 psu for 5 days without mortality under physiological stress. This study suggests to alleviate osmotic stress to fish, a gradually acclimation to increasing salinity is recommended.

• Journal of Plant Biotechnology
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• v.33 no.1
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• pp.11-18
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• 2006

Salt stress is one of major environmental factors influencing plant growth and development. To identify salt tolerance determinants in higher plants, a large-scale screen was conducted with a bialaphos marker-based T-DNA insertional collection of Arabidopsis ecotype C24 mutants. One line for salt stress-sensitive mutant (referred to as ssm1) exhibited increased sensitivity to both ionic (NaCl) and nonionic (mannitol) osmotic stress in a root growth assay. This result suggests that ssm1 mutant is involved in ion homeostasis and osmotic compensation in plant. Molecular cloning of the genomic DNA flanking T-DNA insert of ssm1 mutant was achieved by mutant genomic DNA library screening. T-DNA insertion appeared in the first exon of an open reading frame on F3M18.7, which is the same as AtSYP61. SSM1 is SYP61/OSM1 that is a member of the SNARE superfamily of proteins required for vesicular/target membrane fusions and factor related to abiotic stress.

• Genomics & Informatics
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• v.2 no.2
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• pp.67-74
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• 2004

Cells consistently face stressful conditions, which cause them to modulate a variety of intracellular processes and adapt to these environmental changes via regulation of gene expression. Hyperosmotic and oxidative stresses are significant stressors that induce cellular damage, and finally cell death. In this study, oligonucleotide microarrays were employed to investigate mRNA level changes in cells exposed to hyperosmotic or oxidative conditions. In addition, since heat shock protein 70 (HSP70) is one of the most inducible stress proteins and plays pivotal role to protect cells against stressful condition, we performed microarray analysis in HSP70-overexpressing cells to identify the genes expressed in a HSP70-dependent manner. Under hyperosmotic or oxidative stress conditions, a variety of genes showed altered expression. Down­regulation of protein phosphatase1 beta (PP1 beta) and sphingosine-1-phosphate phosphatase 1 (SPPase1) was detected in both stress conditions. Microarray analysis of HSP70-overexpressing cells demonstrated that diverse mRNA species depend on the level of cellular HSP70. Genes encoding Iysyl oxidase, thrombospondin 1, and procollagen displayed altered expression in all tested conditions. The results of this study will be useful to construct networks of stress response genes.

• Journal of Ecology and Environment
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• v.47 no.3
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• pp.103-116
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• 2023

Background: This study analyzed the physiological adaptations of a woody plant, Vitex rotundifolia, in Goraebul coastal sand dunes from May to September 2022. Environmental factors and physiological of plants growing under field and controlled (pot) conditions were compared. Results: Photosynthesis in plants growing in the coastal sand dunes and pots was the highest in June 2022 and July 2022, respectively. Chlorophyll fluorescence indicated the presence of stress in the coastal sand dune environment. The net photosynthesis rate (P_N) and Y(II) were highest in June in the coastal sand dune environment and July in the pot environment. In August and September, Y(NPQ) increased in the plants in the coastal sand dune environment, showing their photoprotective mechanism. Chlorophyll a and b contents in the pot plant leaves were higher than those in the coastal sand dune plant leaves; however, chlorophyll-a/b ratio was higher in the coastal sand dune plant leaves than in the pot plant leaves, suggesting a relatively high photosynthetic efficiency. Carotenoid content in the coastal sand dune plant leaves was higher in August and September 2022 than that in the pot plant leaves. Leaf water and soluble carbohydrate contents of the coastal sand dune plant leaves decreased in September 2022, leading to rapid leaf abscission. Diurnal variations in photosynthesis and chlorophyll fluorescence in both environments showed peak activity at 12:00 hour; however, the coastal sand dune plants had lower growth rates and Y(II) than the pot plants. Plants in the coastal sand dunes had higher leaf water and ion contents, indicating that they adapted to water stress through osmotic adjustments. However, plants growing in the coastal sand dunes exhibited reduced photosynthetic activity and accelerated decline due to seasonal temperature decreases. These findings demonstrate the adaptation mechanisms of V. rotundifolia to water stress, poor soils, and high temperature conditions in coastal sand dunes. Conclusions: The observed variations indicate the responses of the V. rotundifolia to environmental stress, and may reveal its survival strategies and adaptation mechanisms to stress. The results provide insights into the ecophysiological characteristics of V. rotundifolia and a basis for the conservation and restoration of damaged coastal sand dunes.