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- 저자 : Yi-Chang He (검색결과 22 건)
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He, Xi-Biao,Kim, Mirang,Kim, Seon-Young,Yi, Sang-Hoon,Rhee, Yong-Hee,Kim, Taeho,Lee, Eun-Hye,Park, Chang-Hwan,Dixit, Shilpy,Harrison, Fiona E,Lee, Sang-Hun AlphaMed Press 2015 Stem Cells Vol.33 No.4
<P>Intracellular Vitamin C (VC) is maintained at high levels in the developing brain by the activity of sodium-dependent VC transporter 2 (Svct2), suggesting specific VC functions in brain development. A role of VC as a cofactor for Fe(II)-2-oxoglutarate-dependent dioxygenases has recently been suggested. We show that VC supplementation in neural stem cell cultures derived from embryonic midbrains greatly enhanced differentiation toward midbrain-type dopamine (mDA) neurons, the neuronal subtype associated with Parkinson's disease. VC induced gain of 5-hydroxymethylcytosine (5hmC) and loss of H3K27m3 in DA phenotype gene promoters, which are catalyzed by Tet1 and Jmjd3, respectively. Consequently, VC enhanced DA phenotype gene transcriptions in the progenitors by Nurr1, a transcription factor critical for mDA neuron development, to be more accessible to the gene promoters. Further mechanism studies including Tet1 and Jmjd3 knockdown/inhibition experiments revealed that both the 5hmC and H3K27m3 changes, specifically in the progenitor cells, are indispensible for the VC-mediated mDA neuron differentiation. We finally show that in Svct2 knockout mouse embryos, mDA neuron formation in the developing midbrain decreased along with the 5hmC/H3k27m3 changes. These findings together indicate an epigenetic role of VC in midbrain DA neuron development. Stem Cells2015;33:1320-1332</P>
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Ellagitannins from Camellia oleifera Fruit Shell Extractives
Yi-Chang He,Wei Gao,Jie-Fang Yang,Young-Soo Bae,Chun-Xia Yang,Wei Ding,Zhen-Jun Gu,Mei-Jie Wu,Dong-Bo Yu,Hwang Gao,Cheng Zhou,Chun Gong 강원대학교 산림과학연구소 2022 강원대학교 산림과학연구소 학술대회 Vol.2022 No.10
Camellia is valued not only for its aesthetic contribution as ornament but also for its economic importance as it provides the beverage, tea, and edible oil in some countries, notably China. Apart from its use for ornamental purposes and production of tea, it is one of the four main oil-bearing trees (palm, coconut, olive, and tea) in the world. Camellia oleifera C. Abel, which originated in southern China, is notable as an important source of edible oil obtained from its seeds. It is commonly known as the oil-seed camellia or tea oil camellia, though to a lesser extent other species of Camellia are used in oil production too. Camellia japonica, one of the other tea trees, is distributed in Korea, China, Taiwan, and Japan. Previous studies have revealed that Camellia oleifera has significant biological activities and includes various kinds of chemical constituents such as terpenoids and flavonoids in its leaves, roots, seeds and fruit shells. The others also have reported the recent advances in the utilization of Camellia oleifera C. Abel through a review of nutritional constituents, bio-functional properties, and potential industrial applications. However, there was no study on nut shell extractives of Camellia oleifera even in China and moreover, hydrolysable tannins of the nut shell have never been reported yet. A phytochemical study of fruit shell of Camellia oleifera C. Abel led to the isolation of two ellagitannins, tellimagrandinⅠ(3) and tellimagrandin Ⅱ(4), including gallic acid (1) and ellagic acid (2). The structures of the isolated compounds were unambiguously elucidated on the basis of comprehensive spectroscopic data, especially 2D NMR such as HSQC and HMBC and MS data. Compounds 3 and 4 were first isolated from the extractives of Camellia oleifera fruit shell.
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Gallotannins from Nut Shell Extractives of Camellia oleifera
( Yi-chang He ),( Mei-jie Wu ),( Xiao-lin Lei ),( Jie-fang Yang ),( Wei Gao ),( Young-soo Bae ),( Tae-hee Kim ),( Sun-eun Choi ),( Bao-tong Li ) 한국목재공학회 2021 목재공학 Vol.49 No.3
Camellia nut shell was collected, dried at room temperature and ground to get fine powder. The powder was extracted three times with 95% EtOH, combined, evaporated, and then freeze dried. The crude powder was dissolved in H<sub>2</sub>O and then sequentially fractionated with n-hexane, CH<sub>2</sub>Cl<sub>2</sub>, EtOAc and n-BuOH. A part of EtOAc fraction was chromatographed on a silica gel and on a Sephadex LH-20 columns using MeOH, aqueous MeOH, EtOAc-n-hexane and EtOH-n-hexane to isolate gallotannins. Three gallotannins, 1,2-di-O-galloyl-β-D-glucopyranoside (2), 1,2,6-tri-Ogalloyl- β-D-glucopyranoside (3) and 1,2,3,6-tetra-O-galloyl-β-D-glucopyranoside (4), including gallic acid (1), were isolated and elucidated by NMR and Mass spectroscopies. Although nothing new, these gallotannins were first reported from the nut shell extractives of camellia tree (Camellia oleifera C. Abel). This study was to investigate the chemical constituents, especially hydrolysable tannins, of nut shell extractives of Camellia oleifera and to provide basic information for the future chemical utilization of this species.
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Multifunctional Natural Polysaccharides as Promising Composites for Emerging Intelligent Packaging
Yaxuan Wang,Yaxin Duan,Yi-Chang He,Chun Gong,Ying Xu,Young-Soo Bae,Ting Xu,Chuanling Si 강원대학교 산림과학연구소 2022 강원대학교 산림과학연구소 학술대회 Vol.2022 No.10
Traditionally, food packaging is used to enhance food quality and provide consumers with product descriptions. As a new type of food packaging technology, the new generation of intelligent packaging can sensitively sense changes in the environmental atmosphere of stored food, so as to make a visual response to monitor the quality and freshness of food. This work summarizes the latest research on the development, properties and applications of natural polysaccharide-based smart food packaging materials. Firstly, the intelligent packaging system and polysaccharide-based intelligent packaging are summarized, and several representative polysaccharides are introduced. Secondly, different sensing methods that can be used to detect changes in food properties, such as those based on changes in time, temperature, humidity, oxygen levels, pH, chemical composition, or microbial contamination, are described. Then, the application of polysaccharide-based intelligent packaging materials in the food industry is discussed. Finally, the challenges and future directions of polysaccharide-based intelligent food packaging are discussed.
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Yi, Sang-Hoon,He, Xi-Biao,Rhee, Yong-Hee,Park, Chang-Hwan,Takizawa, Takumi,Nakashima, Kinichi,Lee, Sang-Hun The Company of Biologists Limited 2014 Development (Cambridge) Vol.141 No.4
<P>Understanding how dopamine (DA) phenotypes are acquired in midbrain DA (mDA) neuron development is important for bioassays and cell replacement therapy for mDA neuron-associated disorders. Here, we demonstrate a feed-forward mechanism of mDA neuron development involving Nurr1 and Foxa2. Nurr1 acts as a transcription factor for DA phenotype gene expression. However, Nurr1-mediated DA gene expression was inactivated by forming a protein complex with CoREST, and then recruiting histone deacetylase 1 (Hdac1), an enzyme catalyzing histone deacetylation, to DA gene promoters. Co-expression of Nurr1 and Foxa2 was established in mDA neuron precursor cells by a positive cross-regulatory loop. In the presence of Foxa2, the Nurr1-CoREST interaction was diminished (by competitive formation of the Nurr1-Foxa2 activator complex), and CoREST-Hdac1 proteins were less enriched in DA gene promoters. Consequently, histone 3 acetylation (H3Ac), which is responsible for open chromatin structures, was strikingly increased at DA phenotype gene promoters. These data establish the interplay of Nurr1 and Foxa2 as the crucial determinant for DA phenotype acquisition during mDA neuron development.</P>
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He, Xi-Biao,Yi, Sang-Hoon,Rhee, Yong-Hee,Kim, Hyemin,Han, Yong-Mahn,Lee, Suk-Ho,Lee, Hyunsu,Park, Chang-Hwan,Lee, Yong-Sung,Richardson, Eric,Kim, Byung-Woo,Lee, Sang-Hun AlphaMed Press 2011 Stem cells Vol.29 No.11
<P>Understanding midbrain dopamine (DA) neuron differentiation is of importance, because of physiological and clinical implications of this neuronal subtype. We show that prolonged membrane depolarization induced by KCl treatment promotes DA neuron differentiation from neural precursor cells (NPCs) derived from embryonic ventral midbrain (VM). Interestingly, the depolarization-induced increase of DA neuron yields was not abolished by L-type calcium channel blockers, along with no depolarization-mediated change of intracellular calcium level in the VM-derived NPCs (VM-NPCs), suggesting that the depolarization effect is due to a calcium-independent mechanism. Experiments with labeled DA neuron progenitors indicate that membrane depolarization acts at the differentiation fate determination stage and promotes the expression of DA phenotype genes (tyrosine hydroxylase [TH] and DA transporter [DAT]). Recruitment of Nurr1, a transcription factor crucial for midbrain DA neuron development, to the promoter of TH gene was enhanced by depolarization, along with increases of histone 3 acetylation (H3Ac) and trimethylation of histone3 on lysine 4 (H3K4m3), and decreases of H3K9m3 and H3K27m3 in the consensus Nurr1 binding regions of TH promoter. Depolarization stimuli on differentiating VM-NPCs also induced dissociation of methyl CpG binding protein 2 and related repressor complex molecules (repressor element-1 silencing transcription factor corepressor and histone deacetylase 1) from the CpG sites of TH and DAT promoters. Based on these findings, we suggest that membrane depolarization promotes DA neuron differentiation by opening chromatin structures surrounding DA phenotype genes and inhibiting the binding of corepressors, thus allowing transcriptional activators such as Nurr1 to access DA neuron differentiation gene promoter regions.</P>
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Chemical constituents of Lotus Seed Epicarp
Jing Wu,Yi-Chang He,Yu Zhang,Lei Wu,Young-Soo Bae,Se-Yeong Park,Sun-Eun Choi,Chun Gong 강원대학교 산림과학연구소 2022 강원대학교 산림과학연구소 학술대회 Vol.2022 No.10
Lotus (Nelumbo nucifera Gaertn.) is an important aquatic economic crop in China, and it has been widely cultivated in Asia. Almost every part of lotus (roots, leaves, flowers, and seeds) not only can be used as a food-stuff, but also have multiple medicinal functions [1]. In China, lotus leaves and seeds are publicly identified as both food and medicine resources. There is much research concerned with lotus leaves and seeds. It has been reported that the extract from lotus leaves and seeds have multiple bioactivities, such as being anti-oxidant, anti-inflammatory, immuno-modulatory, and anti-obesity [3-5] etc. The bioactivities of lotus are due to the functional components in lotus including polysaccharides, polyphenols, flavonoids etc. As an inedible part of lotus, lotus seed epicarp also has attracted additional attention. Lotus seed epicarp, the main by-product of lotus seed processing, is also abundant in polyphenols and worthy to be used as a functional food. Lotus seed epicarp extract has been used as a potential antioxidant and anti-obesity additive in Chinese Cantonese Sausage, which was the first use of lotus seed epicarp extract in meat product. However, little is known about the purification and identification of the key compounds from lotus seed epicarp. The aim of this study on the titled plant led to the isolation and purification of eleven known compounds. Eleven compounds ethyl linoleate (1), (e)-9-octadecenoic acid ethyl ester (2), 7β-hydroxy betulinic acid (3), Betulinic acid (4), α-amyrin (5), β-amyrin (6), Kaempferol-3-rutinoside (7), Isorhamnetin-3-O-β-gentiobioside (8), Quercetin (9), Rutin (10), Quercetin-3-O-β-Dgalactopyranoside (11) were isolated from the 95% ethanol extract of lotus seed epicarp. Their structures were elucidated spectroscopically. To the best of our knowledge, It is worth nothing that compounds 1, 2, 3, 4, 5, 6, 7, 8 and 11 were never isolated from this plant.
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Preparation and Properties of CNF/PMMA Composite Film
Yaxin Duan,Jianing Chen,Yi-Chang He,Chun Gong,Hongxiang Xie,Young-Soo Bae,Chuanling Si 강원대학교 산림과학연구소 2022 강원대학교 산림과학연구소 학술대회 Vol.2022 No.10
Nanocellulose has great potential for application as an environmentally friendly new nanomaterial. Polymethyl methacrylate (PMMA), a vitrified polymer with excellent transparency and ease of processing, has also been used as a model polymer for the preparation of nanofiller-reinforced transparent nanocomposites. In this study, aerogels prepared by freeze-drying of cellulose nanofibrils (CNF) hydrogels are used as the basic materials of composite materials, which were impregnated in methyl methacrylate prepolymer. By heat-initiating polymerization and adjusting the concentration of CNF, a CNF/PMMA composite membrane material with excellent mechanical properties, optical properties and thermodynamic properties was prepared. The results showed that the surface of the prepared composites is smooth, the thermodynamic properties of the composite are improved compared with PMMA. Overall, a simple, green and environmentally friendly preparation method of CNF/PMMA composite membrane was developed in this work, which improves the limitations of the preparation of existing lignocellulose-polymer composites.
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