• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.43-43
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• 2014

The rice blast disease caused by of Magnaporthe oryzae is one of the most destructive diseases of rice. By the microarray analysis, we profiled expression changes of genes during conidiation and found out many putative genes that are up-regulated. Among those, we first selected MGG_06399 encoding a dual-specificity tyrosine-regulated protein kinase (DYRK), homologous to YAK1 in yeast. To investigate functional roles of MoYAK1, We made ${\Delta}Moyak1$ mutants by homology dependent gene replacement. The deletion mutant showed a remarkable reduction in conidiation and produced abnormally shaped conidia smaller than those of wild type. The conidia form ${\Delta}Moyak1$ were able to develop a germ tube, but failed to form apppressoria on a hydrophobic coverslip. The ${\Delta}Moyak1$ formed appressria on a hydrophobic cover slip when exogenous cAMP was induced, but the appressoria shape was abnormal. The ${\Delta}Moyak1$ also formed appressoria abberent in shape on onion epidermis and rice sheaths and failed to penetrate the surface of the plants. These data indicate that MoYAK1 is associated with cAMP/PKA pathway and important for conidiation, appressorial formation and pathogenic development in Magnaporthe oryzae. Detailed characterization of MoYAK1 will be presented.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6541-6548
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• 2013

Pigmented rice is mainly black, red, and dark purple, and contains a variety of flavones, tannin, polyphenols, sterols, tocopherols, ${\gamma}$-oryzanols, amino acids, and essential oils. The present study evaluated the cytotoxic effects of purple rice extracts (PREs) combined with chemotherapeutic drugs on human cancer cells and mechanisms of cell death. Methanolic (MeOH) and dichloromethane (DCM) extracts of three cultivars of purple rice in Thailand: Doisaket (DSK), Nan and Payao (PYO), were tested and compared with white rice (KK6). Cytotoxicity was determined by 3-(4, 5-dimethyl)-2, 5-diphenyltetrazolium bromide (MTT) assay in human hepatocellular carcinoma HepG2, prostate cancer LNCaP and murine normal fibroblast NIH3T3 cells. MeOH-PYO-PRE was the most cytotoxic and inhibited HepG2 cell growth more than that of LNCaP cells but was not toxic to NIH3T3 cells. When PREs were combined with paclitaxel or vinblastine, they showed additive cytotoxic effects on HepG2 and LNCaP cells, except for MeOH-PYO-PRE which showed synergistic effects on HepG2 cells when combined with vinblastine. MeOH-PYO-PRE plus vinblastine induced HepG2 cell apoptosis with loss of mitochondrial transmembrane potential (MTP) but no ROS production. MeOH-PYO-PRE-treated HepG2 cells underwent apoptosis via caspase-9 and-3 activation. The level of ${\gamma}$-oryzanol was highest in DCM-PYO-PRE (44.17 mg/g) whereas anthocyanin content was high in MeOH-PYO-PRE (5.80 mg/g). In conclusion, methanolic Payao purple rice extract was mostly toxic to human HepG2 cells and synergistically enhanced the cytotoxicity of vinblastine. Human HepG2 cell apoptosis induced by MeOH-PYO-PRE and vinblastine was mediated through a mitochondrial pathway.

• Journal of Crop Science and Biotechnology
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• v.10 no.4
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• pp.281-286
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• 2007

Gibberellins are growth hormones that play a pivotal role in the growth and development of plants. Present investigations were carried to check the effect of nitrogen(N) and silicon(Si) on bioactive $GA_1$ and its immediate precursor $GA_{20}$ at different growth stages of two rice cultivars with different maturity traits. It was observed that the endogenous bioactive $GA_1$ level gradually increased during vegetative stage and anthesis stage of both Junghwabyeo(early flowering cultivar) and Daesanbyeo(late flowering cultivar). However, the $GA_1$ and $GA_{20}$ content start decreasing during the seed filling stage in both rice cultivars, which indicated a possible relationship of bioactive $GA_1$ and floral development. Our results also confirmed that early 13-hydroxylation pathway was operated at all developmental stages of rice plant. Variation in the levels of the endogenous gibberellins in rice shoots were measured by GCMS-SIM using $^2H_2$-labeled gibberellins as internal standards. Combined application of N and Si enhanced growth parameters and reduced lodging index of both rice cultivars. It was thus concluded that the level of physiologically active $GA_1$ increased during vegetative and early reproductive stage, but starts declining at seed filling stage.

• Journal of Life Science
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• v.12 no.3
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• pp.274-280
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• 2002

The metabolites related to phenylpropanoid pathway play an important role in the self-defense of plants and induced by environmental stress like wounding, pathogen attack, UV-irradiation and so on. The mRNA level of rite phenylalanine ammonia lyase (PAL) was increased at 12 h to 48 h, however it was gradually decreased 48 h to 60 h after UV irradiation. The PAL enzyme activities in rice were peaked at the time of 24 h after UV irradiation, on the other hand, it was not affected by wounding. The PAL enzyme activities in pepper were raised high at 24 h and 10 h by UV irradiation and wounding respectively. The cinnamic acid 4-hydroxylase (C4H) activities were increased by wounding treatment and were detected from 12 h to end time point of experiment, while UV-irradiation didn't affect the C4H activity in rice and pepper. These results were assumed that the action of isoflavonid has an alternative effect on the defenses which include wounding and UV irradiation and on the diverse roles in rice and hot pepper.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.121-121
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• 2017

The productivity of rice has been influenced by various abiotic factors including temperature which cause to limitations to rice yield and quality. Rice yield and quality are adversely affected by high temperature globally. In the present study, four Korean four cultivars such as Dongan, Ilpum, Samkwang, Chucheong were investigated in order to explore molecular mechanisms of high temperature at seedling stage. Rice seedlings grown at $28/20^{\circ}C$ (day/night) were subjected to 7-day exposure to $38/28^{\circ}C$ for high-temperature stress, followed by 2-D based proteomic analysis on biological triplicates of each treatment. The growth characteristics demonstrated that Dongan is tolerant while Ilpum is sensitive to high-temperature stress. High temperature has an adverse effect in the seedling stage both in high temperature sensitive and tolerant cultivar. Two-dimensional gels stained with silver staining, a total of 722 differential expressed protein spots (${\geq}1.5-fold$) were identified using Progenesis SameSpot software. However, a total of 38 differentially expressed protein spots were analyzed by LTQ-FT-ICR MS. Of these, 9 proteins were significantly increased while 10 decreased under high-temperature treatment. Significant changes were associated with the proteins involved in the carbohydrate metabolism, photosynthesis, and stress responses. Proteome results revealed that high-temperature stress had an inhibitory effect on carbon fixation, ATP production, and photosynthetic machinery pathway. The expression level of mRNA is significantly correlated with the results obtained in the proteome investigation. Taken together, these findings provide a better understanding of the high-temperature resistance by proteomic approaches, providing valuable insight into improving the high-temperature stress tolerance in the global warming epoch.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.10
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• pp.51-56
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• 1971

To make certain of the white tip infection on rice, nematodes isolated from the rice seeds grown at Chongdo-goon Isu-myun and Kimje-goon Chooksan-myun were artificially inoculated and their pathway was studied. Also, studies were made for the hot water seed treatment as a measure of white tip control at different levels of water temperature and their germinablity was checked. The results are summarized as follows; 1. Causal nematodes survive in the paddy soil and cause white tip year after year. 2. Causal nematodes can survive in the rice seeds as long as the seeds loose their germinability. 3. Causal nematodes can disseminate throught the irrigation water. 4. Causal nematodes can disseminate through the soil move from a place to other place. 5. Causal nematodes can infect all of the parts of the rice and they can disseminate through any of the parts of rice. 6. The hot water treatment at 5$0^{\circ}C$ for 60 minutes were not effective controlling causal nematodes. But, either treatment of at 55$^{\circ}C$ for 15-20 minutes or at 6$0^{\circ}C$ for 10-15 minutes were effective and germination of seeds was not affected.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.179-179
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• 2005

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3249-3252
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• 2013

We have explored the potential energy surface for the isomerization of the aniline (AN) radical cation to the 2-, 3-, and 4-methylpyridine (picoline, MP) radical cations using G3 model calculations. The isomerization may occur through the 1H-azepine (7-aza-cycloheptatriene) radical cation. A quantitative kinetic analysis has been performed using the Rice-Ramsperger-Kassel-Marcus theory, based on the potential energy surface. The result shows that isomerization between $AN^{+\bullet}$ and each $MP^{+\bullet}$ hardly occurs before their dissociations.

• Molecules and Cells
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• v.19 no.2
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• pp.212-218
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• 2005

A full-length 1.1 kb cDNA, designated Oryza sativa Dehydrin 1 (OsDhn1), was isolated from the seed coat of rice. The deduced protein is hydrophilic and has three K-type and one S-type motifs (SK3-type), indicating that OsDhn1 belongs to the acidic dehydrin family, which includes wheat WCOR410 and Arabidopsis COR47. Expression of OsDhn1 was strongly induced by low temperature as well as by drought. Induction of OsDhn1 by cold stress was clearcut in the roots of seedlings and the epidermis of palea and lemma. OsDhn1 was also up-regulated in UBI::CBF1/DREB1b transgenic plants indicating that it is regulated by the CBF/DREB stress signaling pathway.

• Natural Product Sciences
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• v.26 no.3
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• pp.221-229
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• 2020

This study was undertaken to investigate the protective effect of rice bran oil (RBO) on amyloid β protein (Aβ) (25-35)-induced memory impairment and brain damage in an ICR mouse model. Memory impairment was produced by intracerebroventricular microinjection of 15 nmol Aβ (25-35) and assessed using the passive avoidance test. Treatment with RBO at 0.1, 0.5, or 1 mL/kg (p.o. daily for 8 days) protected against Aβ (25-35)-induced memory impairment. Furthermore, Aβ (25-35)-induced decreases in glutathione and increases in lipid peroxidation and cholinesterase activity in brain tissue were inhibited by RBO, and Aβ (25-35)-induced increases of phosphorylated mitogen-activated protein kinases (MAPKs) and inflammatory factors, and changes in the levels of apoptosis-related proteins were significantly inhibited by RBO. Furthermore, Aβ (25-35) suppressed the PI3K/Akt pathway and the phosphorylation of CREB, but increased phosphorylation of tau (p-tau) in mice brain; these effects were significantly inhibited by administration of RBO. These results suggest that RBO inhibits Aβ (25-35)-induced memory impairment by inducing anti-apoptotic and anti-inflammatory effects, promoting PI3K/Akt/CREB signaling, and thus, inhibiting p-tau formation.