• Nutrition Research and Practice
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• 제11권5호
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• pp.430-434
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• 2017

BACKGROUND/OBJECTIVE: Chronic hyperglycemia induces oxidative stress via accumulation of reactive oxygen species (ROS) and contributes to diabetic complications. Hyperglycemia induces mitochondrial superoxide anion production through the increased activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. This study aimed to determine whether fisetin and luteolin treatments suppress the oxidative stress by modulating the expression of sirtuins (SIRTs) and forkhead box O3a (FOXO3a) under hyperglycemic conditions in human monocytes. MATERIALS/METHODS: Human monocytic cells (THP-1) were cultured under osmotic control (14.5 mmol/L mannitol), normoglycemic (NG, 5.5 mmol/L glucose), or hyperglycemic (HG, 20 mmol/L glucose) conditions, in the absence or presence of fisetin and luteolin for 48 h. To determine the effect of fisetin and luteolin treatments on high glucose-induced oxidative stress, western blotting and intracellular staining were performed. RESULTS: Hyperglycemic conditions increased the ROS production, as compared to normoglycemic condition. However, fisetin and luteolin treatments inhibited ROS production under hyperglycemia. To obtain further insight into ROS production in hyperglycemic conditions, evaluation of p47phox expression revealed that fisetin and luteolin treatments inhibited p47phox expression under hyperglycemic conditions. Conversely, the expression levels of SIRT1, SIRT3, SIRT6, and FOXO3a were decreased under high glucose conditions compared to normal glucose conditions, but exposure to fisetin and luteolin induced the expression of SIRT1, SIRT3, SIRT6, and FOXO3a. The above findings suggest that fisetin and luteolin inhibited high glucose-induced ROS production in monocytes through the activation of SIRTs and FOXO3a. CONCLUSIONS: The results of our study supports current researches that state fisetin and luteolin as potential agents for the development of novel strategies for diabetes.

• Ocean and Polar Research
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• 제26권3호
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• pp.433-438
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• 2004

Stress response to the seawater acclimation in coho salmon (Oncorhynchus kisutch) smolt was investigated. Salt concentration of rearing water was gradually increased for 3 days from freshwater to seawater (30 ppt salt level). The changes of serum concentrations of cortisol as a primary stress indicator, and as secondary indicators, glucose (GLC), lactate (LAC), triglyce.ide (TG), cholesterol (CHOL), sodium ion $(Na^+)$, chloride ion $(Cl^-)$ and enzyme activities (alanine aminotransferase, ALT: aspartate aminotrasferase, AST; lactate dehydrogenase, LDH) were quantified during the acclimation experiment. Among them, cortisol, LAC, TG, CHOL, ALT, AST concentrations showed rapid increase at the first exposure to the 10ppt salt level (day 1), and began to decrease to the constant values after day 2 of adaptation at 20ppt salt level. However, LDH concentration tended to decrease during the whole experimental period. $Na^+\;and\;Cl^-$ showed slight decrease at day 1, and increased to a little bit higher values after day 2 rather than those in freshwater. All the fishes started on taking a food after day 4 of seawater adaptation. From these results, to reduce osmotic shock inducible stress to fish in seawater acclimation, gradual increase of salt levels is recommended.

• BMB Reports
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• 제38권4호
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• pp.432-439
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• 2005

$Ca^{2+}$/calmodulin transduction pathways have been implicated in mediating stress response and tolerance in plants. Here, three genes encoding calmodulin (Cam) members of the EF-hand family of $Ca^{2+}$-binding proteins were identified from Oryza sativa L. databases. Complementary DNA for each of the calmodulin genes, OsCam1, OsCam2, and OsCam3 were sequenced. OsCam1 and OsCam2 encode a conventional 148-amino acid calmodulin protein that contains four characteristic $Ca^{2+}$-binding motifs. OsCam3 encode a similar protein with a 38-amino-acid extension containing a putative prenylation site (CVIL) at the carboxyl terminus. RT-PCR showed that each of the genes is expressed in leaves and roots of 2-week old rice seedlings. By RNA gel blot analysis, OsCam1 mRNA levels strongly increased in response to NaCl, mannitol and wounding treatments. In contrast, OsCam2 mRNA levels were relatively unchanged under all conditions investigated. NaCl treatment and wounding also increased the OsCam3 mRNA level, but in a more transient manner. Our results indicate that although the expression of genes encoding different calmodulin isoforms is ubiquitous, they are differentially regulated by various stress signals. In addition, we have demonstrated that the calcium-channel blocker lanthanum chloride inhibited the induction of OsCam1 gene expression by both NaCl and mannitol treatments. These results suggest that osmotic stress induced expression of OsCam1 gene requires the $[Ca^{2+}]_{cyt}$ elevation that is known to occur in response to these stimuli.

• Clinical and Experimental Pediatrics
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• 제63권8호
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• pp.314-320
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• 2020

Background: The accumulation of unpaired α-globin chains in patients with β-thalassemia major may clinically create ineffective erythropoiesis, hemolysis, and chronic anemia. Multiple blood transfusions and iron overload cause cellular oxidative damage. However, α-tocopherol, an antioxidant, is a potent scavenger of lipid radicals in the membranes of red blood cells (RBCs) of patients with β-thalassemia major. Purpose: To evaluate the effects of α-tocopherol on hemolysis and oxidative stress markers on the RBC membranes of patients with β-thalassemia major. Methods: Forty subjects included in this randomized controlled trial were allocated to the placebo and α-tocopherol groups. Doses of α-tocopherol were based on Institute of Medicine recommendations: 4-8 years old, 200 mg/day; 9-13 years old, 400 mg/day; 14-18 years old, 600 mg/day. Hemolysis, oxidative stress, and antioxidant variables were evaluated before and after 4-week α-tocopherol or placebo treatment, performed before blood transfusions. Results: Significant enhancements in plasma haptoglobin were noted in the α-tocopherol group (3.01 mg/dL; range, 0.60-42.42 mg/dL; P=0.021). However, there was no significant intergroup difference in osmotic fragility test results; hemopexin, malondialdehyde, reduced glutathione (GSH), or oxidized glutathione (GSSG) levels; or GSH/GSSG ratio. Conclusion: Use of α-tocopherol could indirectly improve hemolysis and haptoglobin levels. However, it played no significant role in oxidative stress or as an endogen antioxidant marker in β-thalassemia major.

• Natural Product Sciences
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• 제22권3호
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• pp.201-208
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• 2016

Here in this study, we investigated the lifespan-extending effect and underlying mechanism of methanolic extract of Moringa olelifa leaves (MML) using Caenorhabditis elegans (C. elegans) model system. To define the longevity properties of MML we conducted lifespan assay and MML showed significant increase in lifespan under normal culture condition. In addition, MML elevated stress tolerance of C. elegans to endure against thermal, oxidative and osmotic stress conditions. Our data also revealed that increased activities of antioxidant enzymes and expressions of stress resistance proteins were attributed to MML-mediated enhanced stress resistance. We further investigated the involvement of MML on the aging-related factors such as growth, food intake, fertility, and motility. Interestingly, MML significantly reduced growth and egg-laying, suggesting these factors were closely linked with MML-mediated longevity. We also observed the movement of aged worms to estimate the effects of MML on the health span. Herein, MML efficiently elevated motility of aged worms, indicating MML may affect health span as well as lifespan. Our genetic analysis using knockout mutants showed that lifespan-extension activity of MML was interconnected with several genes such as skn-1, sir-2.1, daf-2, age-1 and daf-16. Based on these results, we could conclude that MML prolongs the lifespan of worms via activation of SKN-1 and SIR-2.1 and inhibition of insulin/IGF pathway, followed by DAF-16 activation.

• 한국작물학회지
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• 제42권6호
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• pp.693-698
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• 1997

1. 삼투 potential($\Psi_\pi$=-10 bar)이 같은 P.E.G.와 NaCl 용액을 사용하여 유묘의 한해와 염해를 비교한 결과 초장, 유묘건물중, 엽록소 함량 그리고 엽수분 potential의 감소와 유리 proline 함량의 증가는 NaCl 처리보다는 P.E.G. 처리구에서 더 심하였다. 2. 유리 아미노산은 무처리(호그랜드 용액)보다 한해유발처리(P.E.G.)에서 2.6배 그리고 염해유발처리(NaCl)에서 3.6배 증가하였으나 유리 proline은 전 아미노산 함량 중 한해과 염해에서 각각 66%와 61%를 차지하였다. 3. P.E.G. 처리구에서는 phenylalanine이 그리고 NaCl 처리에서는 phenylalanine, alanine 및 asparagine이 현저히 증가한 경향이었다. 4. 보리 유묘기의 한해와 염해반응은 전반적으로 볼 때 비교적 동질적이고 유사한 경향이었다.

• Journal of Plant Biotechnology
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• 제37권4호
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• pp.483-493
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• 2010

Knock-out of a gene by insertional mutagenesis is a direct way to address its function through the mutant phenotype. Among ca. 15,000 gene-trapped Ds insertion lines of rice, we identified one line from selected sensitive lines in highly salt stress. We conducted gene tagging by TAIL-PCR, and DNA gel blot analysis from salt sensitive mutant. A gene encoding an oligopeptide transporter (OPT family) homologue was disrupted by the insertion of a Ds transposon into the OsOPT10 gene that was located shot arm of chromosome 8. The OsOPT10 gene (NP_001062118.) has 6 exons and encodes a protein (752 aa) containing the OPT family domain. RT-PCR analysis showed that the expression of OsOPT10 gene was rapidly and strongly induced by stresses such as high-salinity (250 mM), osmotic, drought, $100\;{\mu}M$ ABA. The subcellular localization assay indicated that OsOPT10 was localized specifically in the plasma membrane. Overexpression of OsOPT10 in Arabidopsis thaliana and rice conferred tolerance of transgenic plants to salt stress. Further we found expression levels of some stress related genes were inhibited in OsOPT10 transgenic plants. These results suggested that OsOPT10 might play crucial but differential roles in plant responses to various abiotic stresses.

• The Plant Pathology Journal
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• 제35권5호
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• pp.445-458
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• 2019

The lipopolysaccharide (LPS) composed of lipid A, core, and O-antigen is the fundamental constituent of the outer membrane in gram-negative bacteria. This study was conducted to investigate the roles of LPS in Burkholderia glumae, the phytopathogen causing bacterial panicle blight and seedling rot in rice. To study the roles of the core oligosaccharide (OS) and the O-antigen region, mutant strains targeting the waaC and the wbiFGHI genes were generated. The LPS profile was greatly affected by disruption of the waaC gene and slight reductions were observed in the O-antigen region following wbiFGHI deletions. The results indicated that disruption in the core OS biosynthesis-related gene, waaC, was associated with increased sensitivity to environmental stress conditions including acidic, osmotic, saline, and detergent stress, and to polymyxin B. Moreover, significant impairment in the swimming and swarming motility and attenuation of bacterial virulence to rice were also observed in the waaC-defective mutant. The motility and virulence of O-antigen mutants defective in any gene of the wbiFGHI operon, were not significantly different from the wild-type except in slight decrease in swimming and swarming motility with wbiH deletion. Altogether, the results of present study indicated that the LPS, particularly the core OS region, is required for tolerance to environmental stress and full virulence in B. glumae. To our knowledge, this is the first functional study of LPS in a plant pathogenic Burkholderia sp. and presents a step forward toward full understanding of B. glumae pathogenesis.

• 생물환경조절학회지
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• 제19권4호
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• pp.266-274
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• 2010

본 연구는 토마토의 토양 수분결핍조건에서의 생장과 생리적인 반응을 근본적으로 조사하기 위하여 수행되었다. 토양에 두가지 수분조건, 심한 수분결핍(-100kPa)과, 대조구인 약한 수분결핍 처리(-25kPa)는 실시간 토양수분함량을 모니터링을 할 수 있는 토양센서와 관수 모듈을 갖춘 micro-irrigation 시스템을 고안, 온실에서 유지되었다. 토양수분함량은 30일동안 변동되었으며, -25kPa로 맞춰진 처리구는 평균 -47kPa, -100kPa 처리구는 평균 -119kPa로 차이를 나타냈다. 이 두 가지 다른 토양수분상태에서 자란 식물체 사이의 생육을 비교해 본 결과 수분결핍상태(-100kPa)에서 자란 식물체가 대조구인 약한 수분결핍(-25kPa) 처리구에 비해 절간수의 차이없이 신장이 유의하게 감소하였으며 건물중의 축적은 더 높게 나타났다. 또한 건물중 당 엽면적의 차이 없이, 엽면적과 엽건중이 수분 결핍이 약한 처리구에 비해 수분결핍이 심한 처리구가 더 높게 나타났다. 이러한 생육상의 차이는 심한 수분스트레스가 엽두께의 변화없이 생체중의 증가와 엽면적 확보를 통해 토마토의 수분스트레스에 적응을 야기시킬 수 있음을 제시했다. 수분결핍에 따른 토마토 생육기간동안, 생리적변화를 조사한 결과, -100kPa 처리구에서 자란 토마토가 대조구인 -25kPa 처리구에 비해 엽의 상대수분함량의 증가와 잎의 삼투압이 낮게 나타났다. 이는 수분스트레스아래서 토마토의 더 나은 수분상태를 유지하기 위한 생리적인 적응을 설명해준다. 아울러 심한 수분스트레스는 대조구에 비해 PSII 활성과 수분활용도를 증가되었으며, 낮은 기공저항도를 나타내었다. 처리간의 광합성의 차이는 없었으며, 토마토 과실의 수와 생육량의 차이는 없었다. 이러한 결과는 토마토 'Picco'가 엽형태의 변형과 삼투압, 수분활용도와 PSII의 활성을 통해 수분결핍상태에서 적응할 수 있게 만들 능력을 보여준다. 본 연구결과에서 나타난 토마토의 수분스트레스 적응 메커니즘은 토마토의 가뭄저항성 스크린에 있어서 고려되어져야 할 것으로 보인다.

• KSBB Journal
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• 제10권1호
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• pp.46-54
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• 1995

당근 모상근의 생리학적 특성을 기존의 현탁 배양세포와 영양 요구성의 관점에서 비교, 고찰 하였다. 인산염과 질소원 등 무기 영양분의 영 향은 당근현탁세포에서와 통일하였고 모상근 성 장의 최 척 sucrose 농도는 7%로, 3 % sucrose 농도에서 최대 성장을 보인 현탁세포와는 다른 결과를 나타내였다. 이는 현탁배양세포는 미분 화된 상태로 세포 각각이 외부 환경과 접촉하고 있으므로, 분화되어 기관 스스로 세포 성장에 적합한 환경을 만드는 모상근보다 외부 환경에 민감하게 작용하여 나타나는 현상으로 해석되었다. Sucrose가 모상근의 성장에 미 치는 기작을 밝히기 위하여 삼투압 조절제인 mannitol을 배 지에 첨가하여 sucrose 농도가 생체중량과 건조 중량 각각에 미치는 영향을 고찰하였다. 모상근의 성장은 배지 내 sucrose 농도에 영향을 받았 고, sucrose 농도가 통 일할 때 건조중량 증가는 생체중량 증가보다 크게 나타났다. 따라서 모상 근 배양계에서 sucrose는 삼투압 조절제로서의 역할보다 주로 에너지원의 역할을 하는 것으로 판단되 었다.