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        검색결과 181

        161.
        2014.07 서비스 종료(열람 제한)
        The perturbation of the steady state of reactive oxygen species due to biotic and abiotic stresses in a plant could lead to protein denaturation through the modification of amino acid residues, including the oxidation of methionine residues. Methionine sulfoxide reductases (MSRs) catalyze the reduction of methionine sulfoxide back to the methionine residue. To assess the role of this enzyme, we generated transgenic rice using a pepper CaMSRB2 gene under the control of the rice Rab21 promoter with/without a selection marker, the bar gene. A drought resistance test on transgenic plants showed that CaMSRB2 confers drought tolerance to rice, as evidenced by less oxidative stress symptoms and a strengthened PSII quantum yield under stress conditions, and increased survival rate and chlorophyll index after the re-watering. The results from immunoblotting using a methionine sulfoxide antibody and nano-LC-MS/MS spectrometry suggest that porphobilinogen deaminase (PBGD), which is involved in chlorophyll synthesis, is a putative target of CaMSRB2. The oxidized methionine content of PBGD expressed in E. coli increased in the presence of H2O2, and the Met-95 and Met-227 residues of PBGD were reduced by CaMSRB2 in the presence of dithiothreitol. An expression profiling analysis of the overexpression lines also suggested that photosystems are less severely affected by drought stress. Our results indicate that CaMSRB2 might play an important functional role in chloroplasts for conferring drought stress tolerance in rice
        162.
        2013.07 서비스 종료(열람 제한)
        Phosphorus is one of the macronutrients essential for plant growth and development, as well as crop productivity. Many soils around the world are deficient in phosphate (Pi) that plants can utilize. To cope with the stress of Pi starvation, plants have evolved many adaptive strategies, such as changes of root architecture and enhanced Pi acquisition form soil. To understand molecular mechanism underlying Pi starvation stress signaling, we characterized the activation-tagged mutant showing altered responses to Pi deficiency compared to wild type Arabidopsis and named hsp3 (hypersensitive to Pi starvation3). hsp3 mutant exhibits enhanced phosphate transporter activity, resulting in higher Pi content than wild type. However, in root architectural change under Pi starvation, hsp3 shows hyposensitive responses than wild type, such as longer primary root elongation, lower lateral root density. Histochemical analysis using hsp3 mutant expressing auxin-responsive DR5::GUS reporter gene, indicated that auxin allocation from primary to lateral roots under Pi starvation is aborted in hsp3 mutant. Molecular genetic analysis of hsp3 mutant revealed that the mutant phenotype is caused by the lesion in ENHANCED SILENCING PHENOTYPE4 (ESP4) gene whose function is proposed in mRNA 3’ end processing. Here, we propose that mRNA processing plays a crucial role in Pi homeostasis in Arabidopsis.
        163.
        2013.07 서비스 종료(열람 제한)
        In order to adapt to various environmental stresses, plants have employed diverse regulatory mechanisms of gene expression. Epigenetic changes, such as DNA methylation and histone modifications play an important role in gene expression regulation under stress condition. It has been known that some of epigenetic modifications are stably inherited after mitotic and meiotic cell divisions, which is known as stress memory. To understand molecular mechanisms underlying stress memory mediated by epigenetic modifications, we developed Arabidopsis suspension-cultured cell lines adapted to high salt by stepwise increases in the NaCl concentration up to 120 mM. Adapted cell line to 120 mM NaCl, named A120, exhibited enhanced salt tolerance compared to unadapted control cells (A0). Moreover, the salt tolerance of A120 cell line was stably maintained even in the absence of added NaCl, indicating that the salt tolerance of A120 cell line was memorized even after the stress is relieved. By using salt adapted and stress memorized cell lines, we intend to analyze the changes of DNA methylation, histone modification, transcriptome, and proteome to understand molecular mechanisms underlying stress adaptation as well as stress memory in plants.
        164.
        2013.02 KCI 등재 서비스 종료(열람 제한)
        Since most merchant vessels are mainly influenced by the added resistance in an actual sea, they could be navigated more efficiently if this added resistance could be precisely predicted and then effectively reduced. In this paper, we have computed the effective horsepower based on the resistance performance in still water and then calculated the added resistance in regular wave in order to estimate a ship's propulsion performance on a voyage. Firstly, we have performed experiments using a model of KCS in a circulating water channel to estimate the flow characteristics around a container ship and the ship's resistance in still water. Then we have calculated the motion response function in regular wave as well as the values for the increase in resistance, and evaluated the ship's motion performance in waves according to the calculated response function. It was found that the resistance in waves increased because the ship's motion response value became larger as the ship's speed increased in the case of head sea. The effect of the added resistance could be reduced by maneuvering the ship to the encounter angle of 120˚ in areas of long wavelengths and to head sea in areas of short wavelengths.
        165.
        2012.07 서비스 종료(열람 제한)
        Phosphorus is one of the macronutrients essential for plant growth and development, as well as crop productivity. Many soils around the world are deficient in phosphate (Pi) that plants can utilize. To cope with the stress of Pi starvation, plants have evolved many adaptive strategies, such as changes of root architecture and enhanced Pi acquisition form soil. To understand molecular mechanism underlying Pi starvation stress signaling, we characterized the activation-tagged mutant showing altered responses to Pi deficiency compared to wild type Arabidopsis and named hsp3 (hypersensitive to Pi starvation3). hsp3 mutant exhibits enhanced phosphate transporter activity, resulting in higher Pi content than wild type. However, in root architectural change under Pi starvation, hsp3 shows hyposensitive responses than wild type, such as longer primary root elongation, lower lateral root density. Histochemical analysis using hsp3 mutant expressing auxin-responsive DR5::GUS reporter gene, indicated that auxin allocation from primary to lateral roots under Pi starvation is aborted in hsp3 mutant. Molecular genetic analysis of hsp3 mutant revealed that the mutant phenotype is caused by the lesion in ENHANCED SILENCING PHENOTYPE4 (ESP4) gene whose function is proposed in mRNA 3’ end processing. Here, we propose that mRNA processing plays a crucial role in Pi homeostasis in Arabidopsis.
        166.
        2012.07 서비스 종료(열람 제한)
        In order to adapt to various environmental stresses, plants have employed diverse regulatory mechanisms of gene expression. Epigenetic changes, such as DNA methylation and histone modifications play an important role in gene expression regulation under stress condition. It has been known that some of epigenetic modifications are stably inherited after mitotic and meiotic cell divisions, which is known as stress memory. To understand molecular mechanisms underlying stress memory mediated by epigenetic modifications, we developed Arabidopsis suspension-cultured cell lines adapted to high salt by stepwise increases in the NaCl concentration up to 120 mM. Adapted cell line to 120 mM NaCl, named A120, exhibited enhanced salt tolerance compared to unadapted control cells (A0). Moreover, the salt tolerance of A120 cell line was stably maintained even in the absence of added NaCl, indicating that the salt tolerance of A120 cell line was memorized even after the stress is relieved. By using salt adapted and stress memorized cell lines, we intend to analyze the changes of DNA methylation, histone modification, transcriptome, and proteome to understand molecular mechanisms underlying stress adaptation as well as stress memory in plants.
        167.
        2012.03 KCI 등재 서비스 종료(열람 제한)
        In order to get information on tocopherol content and composition in fifty-six soybean germplasms were evaluated by HPLC. From the principle component analysis, the first three components accounted for 71.6% of the total variance of tocopherol content in the germplasms. Principal component 1 showed significant correlations with all the morphological markers except 100-seed weight. Soybean germplasms were divided into three groups by the first two principal components. The highest content of α -tocopherol was 38.6~mug per g in Tanner, while that of ~gamma -tocopherol was 195.6~mug in PI 91073. In case of δ -tocopherol, IT 105622 showed the highest value as 29.8~mug . The contents of tocopherol were gradually increased from the late August to late September, which was 10 days before maturity, in Alchankong and PI 96322. The tocopherol content was higher in seeds from the plants sown early than those sown late. Total tocopherol contents of PI 96188, Geomjeongkong 2, and Suwon 183 grown in Gimje were higher than those grown in Iksan, but the difference was not observed in PI 96322. These results suggest that the contents of tocopherol in soybean were affected not only by the genotypes but also by environment.
        168.
        2010.04 KCI 등재 서비스 종료(열람 제한)
        The characteristics of rice starch by sampling six rice cultivars for making rice bread were examined. Six rice varieties exhibited different level of amylose content and the ratio of chain length distribution within the amylopectin cluster. Especially, examination by colorimetric measurement of starch-I2 complex showed the maximum absorption wavelength was the highest in Goamibyeo. The X-ray diffraction patterns of starch granules showed the traditional "A" type, except in Goami 2 and Goami 3 and there was difference in crystalline of rice starch. There were significant difference in the changes of swelling power of rice starches through temperature. We could also found that the six rice cultivars had different levels of the hydrolysis rate by 5% glucoamylase. These results could suggest that properties of rice starch impact on the level of loaf formation and specific gravity of rice bread after baking.
        169.
        2010.04 KCI 등재 서비스 종료(열람 제한)
        To investigate the possibility of brown rice and germinated brown rice as a functional food, the present study evaluates bio-active components of 70% ethanol extracts from brown rice and germinated brown rice of each 7 varieties. Reducing power have been used to investigate the relative antioxidant activities of extract. The contents of r-oryzanol was measured by spectrophotometric methods and vitamin E was carried out by HPLC. The mineral contents was also determined by ICP (Inductive Coupled Plasma) analysis method. In an anticancer test using NCl-H460 and MCF7 cell lines, the 70% EtOH extracts of brown rice and germinated brown rice showed inhibitory effect of approximately 30% against MCF cell lines (Breast cancer) at 100 ㎍/mL concentration. The extraction yield of tested brown rice and germinated brown rice were 2.05~3.80% and 1.36~3.32%, respectively. The r-oryzanol content from some germinated brown rice showed slightly higher than brown rice. The mean contents of most minerals were also higher in germinated brown rice than brown rice. However, vitamin E contents showed higher in brown rice than germinated brown rice except Keunnun, Hongjinju, Nokmi.
        170.
        2010.04 KCI 등재 서비스 종료(열람 제한)
        Corn (Zea mays.L) is the second leading cereal in Myanmar and an important commodity in earning farmers’ income and foreign currencies. To increase productivity, development of locally adapted better hybrid is strongly needed. For upgrading the hybrid corn research and development program, Department of Agricultural Research (DAR) invited the International Corn Foundation (ICF)/Kyungpook National University (KNU) in 2005. Under this collaborative program, research on genetic potential of exotic germplasm introduced from Nepal, Hawaii, Korea, China and IITA has been carried out in 2009 rainy season. Yield trials of 108 and 80 combinations of Myanmar lines and exotic germplasm (Normal × Normal crosses, Normal × Super-sweet) were carried out in Tatkone, Yezin (central zone), Nyaung Mon (north zone), Aung Ban (highland zone) research stations, respectively. These experimental crosses are produced in Korea and Cambodia, 2008. Two to five outstanding hybrids have been selected for three respective zones. Selected hybrids yielded 50-100% more than the best commercial hybrid, CP888 imported from Thailand.The hybrids are tolerant to Rhizoctonia blight in the Tatkone, Exserohilum turcicum blight in Aung Ban, and E. turcicum and stem borers in the Nyaung Mon. A couple of normal super-sweet corn hybrids were selected for nutrition, sugar and vitamin A+. These results point out that introgression of exotic alleles has a potential to increase the heterotic response in yield and biotic resistance. Thus, an understanding of the heterotic relationship between adapted and exotic is needed to exploit exotic germplasm intelligently.
        171.
        2009.12 KCI 등재 서비스 종료(열람 제한)
        Road and maritime transport which connecting main cities in the world is already fully saturated, and the loss cost caused by recent high oil prices is getting bigger. Transportation by inland waterway is rising as an alternative method of them. Concerning this, the GI Waterway is on construction to connect the Yellow sea and Seoul. Nevertheless, there are no existing aids to navigation around the area and no studies have been carried out for them. As the construction progresses, installation of proper aids to navigation should be considered and profound studies need to be carried out. This study focused on introduction of the cases and the systems of other countries inland waterway aids to navigation and suggested a suitable navigation aids system along the inland waterways in Korea and a way of installation for that system.
        172.
        2008.06 KCI 등재 서비스 종료(열람 제한)
        Recently it was known that the problems of nearshore processes and damage of berth and counter facilities frequently had appeared at the small fishery port, such as Daebang near Samcheonpo city, Korea. Here we try to analyze the impact of the rearrangement of counter facilities and berth layout adopted for tranquility of its inner harbor. Because this harbor is being connected to Daebang channel, the rearrangement of the structures might affect to the current speed and direction and wave height, so do to the sea bottom undulation. Therefore, we made model test for the several layouts of the berth and breakwater in this area. Numerical model result shows that the bottom was eroded by 1m by tidal currents and the speed of flow did not shrink, even after the construction work was completed. The direction of the sand movement was downdrift. Although the model study gave reasonable description of beach processes and approach channel sedimentation mechanism, it is necessary to compare with the field history, including the records of waves, tides and bottom materials, etc. for better prediction.
        179.
        2007.03 KCI 등재 서비스 종료(열람 제한)
        A new single cross waxy corn (Zea mays L.) hybrid, “Miheugchal” with black kernel was developed by the Maize Experiment Station (MES), Gangwon-do Agricultural Research and Extension Services (GARES) in 2004. This hybrid, which has good eating quality and
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