• Reproductive and Developmental Biology
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• v.35 no.1
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• pp.9-15
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• 2011

The functional cardiovascular system is comprised of distinct mesoderm-derived lineages including endothelial cells, vascular smooth muscle cells and other mesenchymal cells. Recent studies in the human embryonic stem cell differentiation model have provided evidence indicating that these cell lineages are developed from the common progenitors such as hemangioblasts and cardiovascular progenitor cells. Also, the studies have suggested that these progenitors have a common primordial progenitor, which expresses KDR (human Flk-1, also known as VEGFR2, CD309). We demonstrate here that sustained activation of BMP4 (bone morphogenetic protein 4) in hESC line, CHA15 hESC results in $KDR^+$ mesoderm specific differentiation. To determine whether the $KDR^+$ population derived from hESCs enhances potential to differentiate along multipotential mesodermal lineages than undifferentiated hESCs, we analyzed the development of the mesodermal cell types in human embryonic stem cell differentiation cultures. In embryoid body (EB) differentiation culture conditions, we identified an increased expression of $KDR^+$ population from BMP4-stimulated hESC-derived EBs. After induction with additional growth factors, the $KDR^+$ population sorted from hESCs-derived EBs displays mesenchymal, endothelial and vascular smooth muscle potential in matrix-coated monolayer culture systems. The populations plated in monolayer cultures expressed increased levels of related markers and exhibit a stable/homologous phenotype in culture terms. In conclusion, we demonstrate that the $KDR^+$ population is stably isolated from CHA15 hESC-derived EBs using BMP4 and growth factors, and sorted $KDR^+$ population can be utilized to generate multipotential mesodermal progenitors in vitro, which can be further differentiated into cardiovascular specific cells.

• Research in Plant Disease
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• v.14 no.2
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• pp.79-84
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• 2008

A wilt disease on lettuce was observed in 2006 and 2007 in commercial plastic house at main production areas of lettuce in Icheon, Yongin and Goyang of Gyeonggi Province. The disease was characterized by the wilting of lower leaves, accompanied by stunting symptoms of the whole plants. Old affected stems showed the black streak in the vascular system. The pathogen, Fusarium oxysporum f. sp. lactucae was isolated from stems and roots of diseased plants. Isolated pathogen also produced the microconidia and macroconidia with chlamydospores on carnation leaf agar medium. The pathogen easily invaded and made many chlamydospores on the roots of lettuce and also made dark streaking through the vascular in the lettuce stems. The density of Fusarium sp. in the severely diseased field soil was more higher populations than that in the healthy and less diseased field soil. The minimum population of pathogen would be above $10^3$cfu/g soil to induce the Fusarium wilt on lettuce in plastic house. The results of pathogenicity test showed 'Sunpung' and 'Mipungpochap' was high susceptible to Fusarium pathogen isolates while some cultivar 'Mihongjeokchukmyeon' and 'Jinjachukmyeon' showed moderate resistance. Disease development for some lettuce was related to treated temperature, so the symptom was more severe above $25^{\circ}C$. Selection of appropriate lettuce cultivar and planting time should be related for the successful control of Fusarium wilt.

• Korean Journal of Plant Resources
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• v.23 no.4
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• pp.274-292
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• 2010

The flora of resource plants in Middle and Northern region of Yangsan-si were investigated for 7 times from March to Sept., 2009. The study indicated that, based on voucher specimens, the flora of this area consist of 427 taxa in total; 90 families, 256 genera, 376 species, 4 subspecies, 41 varieties and 6 forms. The resource plants in this area were categorized by their use into 9 groups inclusive of 1 unidentified group. Resources plants which were investigated in this area were 167 edible, 132 pasturing, 118 medicinal, 98 stainable, 52 ornamental, 15 timber, 6 fiber, 2 industrial taxa and 101 unknown resource plants, respectively. Also, there were remarkable plants such as 16 taxa of Korean endemic plants and 36 taxa of specific plants which were designated by the Ministry of Environment. Furthermore, 22 taxa of naturalized plants were observed in this investigated area where Urban Indexn UI) was 8.9%. Although the ecological status of investigated area was comparatively well conserved, the degree of (UI) was relatively high. Based on the results of this investigation, UI has been rapidly increased due to urbanization and construction of recreation objects in this area.

• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.309-332
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• 2015

To investigate the distribution of vascular plants growing in Mt. Taebaeksan, a survey was conducted from April, 2014 to October, 2014. The flora of Mt. Taebaeksan was classified as a total of 406 taxa comprising of 79 families, 238 genus, 352 species, 4 subspecies, 43 varieties and 7 forma. Among them, 8 taxa were identified as endemic plants in Korea including Salix koriyanagi Kimura, Aconitum pseudolaeve Nakai, Anemone koraiensis Nakai, etc. 16 taxa of Korean rare plants species were identified including 4 taxa in the degree of VU (Asplenium spinulosum (Maxim.) Milde, etc.) and 12 taxa in the degree of LC (Clematis koreana Kom., Eranthis stellata Maxim., Aristolochia manshuriensis Kom., etc.) The floristic special plants were a total of 107 taxa which consist of 3 taxa in degree V(Polypodium virginianum L., etc.), 14 taxa in degree IV(Asplenium otophorum (Miq.) Koidz., etc.), 31 taxa in degree III (Abies nephrolepis (Trautv.) Maxim., etc.), 32 taxa in degree II(Lycopodium chinense H.Christ, etc.) and 27 taxa in degree I(Dryopteris crassirhizoma Nakai, etc.). For the naturalized plants, 16 taxa were identified (Fallopia dumetorum (L.) Holub, Rumex crispus L., Cerastium glomeratum Thuill). Also, the percentage of urbanization index was 5 %, and the naturalized plant index was 3.9 % respectively.

• Journal of Ecology and Environment
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• v.45 no.3
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• pp.143-151
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• 2021

Background: Plants are able to optimize defense responses induced by various herbivores, which have different feeding strategies. Local and systemic responses within a plant after herbivory are essential to modulate herbivore-specific plant responses. For instance, leaf-chewing herbivores elicit jasmonic acid signaling, which result in the inductions of toxic chemicals in the attacked leaf (tissue-specific responses) and also in the other unattacked parts of the plant (systemic responses). Root herbivory induces toxic metabolites in the attacked root and alters the levels of transcripts and metabolites in the unattacked shoot. However, we have little knowledge of the local and systemic responses against stem-boring herbivores. In this study, we examined the systemic changes in metabolites in the wild tobacco Nicotiana attenuata, when the stem-boring herbivore Trichobaris mucorea attacks. Results: To investigate the systemic responses of T. mucorea attacks, we measured the levels of jasmonic acid (JA), JA-dependent secondary metabolites, soluble sugars, and free amino acids in 7 distinct tissues of N. attenuata: leaf lamina with epidermis (LLE), leaf midrib (LM), stem epidermis (SE), stem pith (SP), stem vascular bundle (SV), root cortex with epidermis (RCE), and root vascular bundle (RV). The levels of JA were increased in all root tissues and in LM by T. mucorea attacks. The levels of chlorogenic acids (CGAs) and nicotine were increased in all stem tissues by T. mucorea. However, CGA was systematically induced in LM, and nicotine was systematically induced in LM and RCE. We further tested the resource allocation by measuring soluble sugars and free amino acids in plant tissues. T. mucorea attacks increased the level of free amino acids in all tissues except in LLE. The levels of soluble sugars were significantly decreased in SE and SP, but increased in RV. Conclusions: The results reveal that plants have local- and systemic-specific responses in response to attack from a stem-boring herbivore. Interestingly, the level of induced secondary metabolites was not consistent with the systemic inductions of JA. Spatiotemporal resolution of plant defense responses against stem herbivory will be required to understand how a plant copes with attack from herbivores from different feeding guilds.

• Journal of Life Science
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• v.33 no.9
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• pp.703-712
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• 2023

Angiogenesis, the formation of blood vessels from pre-existing vessels, is a multistep process regulated by modulators of angiogenesis. It is essential for various physiological processes, such as embryonic development, chronic inflammation, and wound repair. Dysregulation of angiogenesis causes many diseases, such as cancer, autoimmune diseases, rheumatoid arthritis, cardiovascular disease, and delayed wound healing. However, the number of effective anti-angiogenic drugs is limited. Recent research has focused on identifying potential drug candidates from natural sources. For example, marine natural products have been shown to have anti-cancer, anti-oxidant, anti-inflammatory, antiviral, and wound-healing effects. Thus, this study aimed to describe the angiogenesis inhibitory effect of Hizikia fusiforms (brown algae) extract. The hexane extract of H. fusiformis has shown inhibitory effects on in vitro angiogenesis assays, such as cell migration, invasion, and tube formation in human umbilical vein endothelial cells (HUVECs). The hexane extract of H. fusiformis (HFH) inhibited in vivo angiogenesis in a mouse Matrigel gel plug assay. In addition, the protein expression of vascular endothelial growth factor (VEGF), mitogen-activated protein kinase (MAPK)/extracellular signal kinase, and AKT serine/threonine kinase 1 decreased following treatment with H. fusiformis extracts. Our results demonstrated that the hexane extract of H. fusiformis (HFH) inhibits angiogenesis in vitro and in vivo.

• Journal of Life Science
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• v.34 no.6
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• pp.399-407
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• 2024

Angiogenesis is the process by which new blood vessels form from existing blood vessels. This phenomenon occurs during growth, healing, and menstrual cycle changes. Angiogenesis is a complex and multifaceted process that is important for the continued growth of primary tumors, metastasis promotion, the support of metastatic tumors, and cancer progression. Impaired angiogenesis can lead to cancer, autoimmune diseases, rheumatoid arthritis, cardiovascular disease, and delayed wound healing. Currently, there are only a handful of effective antiangiogenic drugs. Recent studies have shown that natural marine products exhibit antiangiogenic effects. In a previous study, we reported that the hexane extract of H. fusiformis (HFH) could inhibit the development of new blood vessels both in vitro and in vivo. The aim of this study was to describe the inhibitory effect of chloroform extracts of H. fusiformis on angiogenesis. To investigate how chloroform extract prevents blood vessel growth, we examined its effects on HUVEC, including cell migration, invasion, and tube formation. In a mouse Matrigel plug assay, H. fusiformis chloroform extract (HFC) also inhibited angiogenesis in vivo. Certain proteins associated with blood vessel growth were reduced after HFC treatment. These proteins include vascular endothelial growth factor (VEGF), mitogen-activated protein kinase (MAPK)/extracellular signal transduction kinase, and serine/threonine kinase 1 (AKT). These studies have shown that the chloroform extract of H. fusiformis can inhibit blood vessel growth both in vitro and in vivo.

• Journal of Life Science
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• v.29 no.1
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• pp.9-17
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• 2019

As tumors develop, they encounter microenvironmental stress, such as hypoxia and glucose depletion, due to poor vascular function, thereby leading to necrosis, which is observed in solid tumors. Necrotic cells are known to release cellular cytoplasmic contents, such as high mobility group box 1 (HMGB1), into the extracellular space. The release of HMGB1, a proinflammatory and tumor-promoting cytokine, plays an important role in promoting inflammation and metabolism during tumor development. Recently, HMGB1 was shown to induce the epithelial-mesenchymal transition (EMT) and metastasis. However, the underlying mechanism of the HMGB1-induced EMT, invasion, and metastasis is unclear. In this study, we showed that noninvasive breast cancer cells MCF-7 formed tightly packed, rounded spheroids and that the cells in the inner regions of a multicellular tumor spheroid (MTS), an in vitro model of a solid tumor, led to necrosis due to an insufficient supply of O2 and glucose. In addition, after 7 d of MTS culture, the EMT was induced via the transcription factor Snail. We also showed that HMGB1 receptors, including RAGE, TLR2, and TLR4, were induced by MTS culture. RAGE, TLR2, and TLR4 shRNA inhibited MTS growth, supporting the idea that RAGE/TLR2/TLR4 play critical roles in MTS growth. They also prevented MTS culture-induced Snail expression, pointing to RAGE/TLR2/TLR4-dependent Snail expression. RAGE, TLR2, and TLR4 shRNA suppressed the MTS-induced EMT. In human cancer tissues, high levels of RAGE, TLR2, and TLR4 were detected. These findings demonstrated that the HMGB-RAGE/TLR2/TLR4-Snail axis played a crucial role in the growth of the MTS and MTS culture-induced EMT.

• Reproductive and Developmental Biology
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• v.32 no.4
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• pp.223-227
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• 2008

Human embryonic stem (ES) cells retain the capacity for self-renewal, are pluripotent and differentiate into the three embryonic germ layer cells. The regulatory transcription factors Oct4, Nanog and Sox2 play an important role in maintaining the pluripotency of human ES cells. The aim of this research was to identify unknown genes upregulated in human ES cells along with Oct4, Nanog, and Sox2. This study characterizes an unknown gene, named chromosome 1 open reading frame 31 (C1orf31) mapping to chromosome 1q42.2. The product of C1orf31 is the hypothetical protein LOC388753 having a cytochrome c oxidase subunit VIb (COX6b) motif. In order to compare expression levels of C1orf31 in human ES cells, human embryoid body cells, vascular angiogenic progenitor cells (VAPCs), cord-blood endothelial progenitor cells (CB-EPCs) and somatic cell lines, we performed RT-PCR analysis. Interestingly, C1orf31 was highly expressed in human ES cells, cancer cell lines and SV40-immortalized cells. It has a similar expression pattern to the Oct4 gene in human ES cells and cancer cells. Also, the expression level of C1orf31 was shown to be upregulated in the S phase and early G2 phase of synchronized HeLa cells, leading us to purpose that it may be involved in the S/G2 transition process. For these reasons, we assume that C1orf31 may play a role in on differentiation of human ES cells and carcinogenesis.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.95-99
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• 2002

To investigate the manual procedure for custom fitting of ocular prosthesis and the cytotoxicity induced by extract solution of prosthetic eye, this study was performed. These procedures included the trial fitting of the wax model, impression molding, the an of iris color duplication, sclera mold made from the prosthetic wax model, scleral tints and vascular pattern, finishing and polishing. Inhibition of cell growth for extract solution was measured by MTT assay. Extract solution did not show the cytotoxicity. This study suggests that the manual procedure for custom fitting of ocular prosthesis is good for education of students.