• Genomics & Informatics
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• v.2 no.2
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• pp.67-74
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• 2004

Cells consistently face stressful conditions, which cause them to modulate a variety of intracellular processes and adapt to these environmental changes via regulation of gene expression. Hyperosmotic and oxidative stresses are significant stressors that induce cellular damage, and finally cell death. In this study, oligonucleotide microarrays were employed to investigate mRNA level changes in cells exposed to hyperosmotic or oxidative conditions. In addition, since heat shock protein 70 (HSP70) is one of the most inducible stress proteins and plays pivotal role to protect cells against stressful condition, we performed microarray analysis in HSP70-overexpressing cells to identify the genes expressed in a HSP70-dependent manner. Under hyperosmotic or oxidative stress conditions, a variety of genes showed altered expression. Down­regulation of protein phosphatase1 beta (PP1 beta) and sphingosine-1-phosphate phosphatase 1 (SPPase1) was detected in both stress conditions. Microarray analysis of HSP70-overexpressing cells demonstrated that diverse mRNA species depend on the level of cellular HSP70. Genes encoding Iysyl oxidase, thrombospondin 1, and procollagen displayed altered expression in all tested conditions. The results of this study will be useful to construct networks of stress response genes.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.50.2-51
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• 2021

Stars form exclusively in cold and dense molecular clouds. To fully understand star formation processes, it is hence a key to investigate how molecular clouds form out of the surrounding diffuse atomic gas. With an aim of shedding light in the process of the atomic-to-molecular transition in the interstellar medium, we analyze Arecibo HI emission and absorption spectral pairs along with TRAO/PMO 12CO(1-0) emission spectra toward 58 lines of sight probing in and around molecular clouds in the solar neighborhood, i.e., Perseus, Taurus, and California. 12CO(1-0) is detected from 19 out of 58 lines of sight, and we report the physical properties of HI (e.g., central velocity, spin temperature, and column density) in the vicinity of CO. Our preliminary results show that the velocity difference between the cold HI (Cold Neutral Medium or CNM) and CO (median ~ 0.7 km/s) is on average more than a factor of two smaller than the velocity difference between the warm HI (Warm Neutral Medium or WNM) and CO (median ~ 1.7 km/s). In addition, we find that the CNM tends to become colder (median spin temperature ~ 43 K) and abundant (median CNM fraction ~ 0.55) as it gets closer to CO. These results hints at the evolution of the CNM in the vicinity of CO, implying a close association between the CNM and molecular gas. Finally, in order to examine the role of HI in the formation of molecular gas, we compare the observed CNM properties to the theoretical model by Bialy & Sternberg (2016), where the HI column density for the HI-to-H2 transition point is predicted as a function of density, metallicity, and UV radiation field. Our comparison shows that while the model reproduces the observations reasonably well on average, the observed CNM components with high column densities are much denser than the model prediction. Several sources of this discrepancy, e.g., missing physical and chemical ingredients in the model such as the multi-phase ISM, non-equilibrium chemistry, and turbulence, will be discussed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.6
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• pp.616-621
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• 2008

Osseointegration is a result of bone formation and bone regeneration processes, which takes place at the interface between bone and implant, and it indicates a rigid fixation that can be stably maintained while functional loading is applied inside the oral cavity as well as after implant placement. Although many researches were carried out about osseointegration mechanism, but cellular and molecular events have not been clarified. With recent development of molecular biology, some researches have examined biological determinants, such as cytokine, growth factors, bone matrix proteins, during osseointegration between bone and implant surface, other researches attempted to study the ways to increase bone formation by adhering protein to implant surface or by inserting growth factors during implant placement. Cellular research on the reaction of osteoblast especially to surface morphology (e.g. increased roughness) has been carried out and found that the surface roughness of titanium implant affects the growth of osteoblast, cytokine formation and mineralization. While molecular biological research in dental implant is burgeoning. Yet, its results are insignificant. We have been studying the roles of growth factors during osseointegration, comparing different manifestations of growth factors by studying the effect of osseointegration that varied by implant surface. Of many growth factors, $TGF-{\beta}$, IGF-I, BMP2, and BMP4, which plays a significant role in bone formation, were selected, and examined if these growth factors are manifested during osseointegration. The purpose of this article is to present result of our researches and encourage molecular researches in dental implant.

• Proceedings of the Botanical Society of Korea Conference
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• 1995.07a
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• pp.57-86
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• 1995

Molecular mapping of plant genomes has progressed rapidly since Bostein et al.(1980) introduced the idea of constructing linkage maps of human genome based on restriction fragment length polymorphism (RFLP) markers. In recent years, the development of protein and DNA markers has stimulated interest for the new approaches to plant improvement. While classical maps based on morphological mutant markers have provided important insights into the plant genetics and cytology, the molecular maps based on molecular markers have a number of inherent advatages over classical genetic maps for the applications in genetic studies and/or breeding schemes. Isozymes and DNA markers are numerous, discrete, non-deleterious, codominant, and almost entirely free of environmental and epistatic interactions. For these reasons, they are widely used in constructing detailed linkage maps in a number of plant species. Plant breeders improve crops by selecting plants with desirable phenotypes. However a plant's phenotyes is often under genetic control, positioning at different "quantitative trait loci" (QTLs) together with environmental effects. Molecular maps provide a possible way to determine the effect of the individual gene that combines to produce a quantitative trait because the segregation of a large number of markers can be followed in a single genetic cross. Using market-assisted selection, plants that contain several favorable genes for the trait and do not contain unfavourable segments can be obtained during early breeding processes. Providing molecular maps are available, valuable data relevant to the taxonomic relationships and chromosome evolution can be accumulated by comparative mapping and also the structural relationships between linkage map and physical map can be identified by cDNA sequencing. After constructing high density maps, it will be possible to clone genes, whose products are unknown, such as semidwarf and disease resistance genes. However, much attention has to be paid to level-up the basic knowledge of genetics, physiology, biochemistry, plant pathology, entomology, microbiology, and so on. It must also be kept in mind that scientists in various fields will have to make another take off by intensive cooperation together for early integration and utilization of these newly emerging high-techs in practical breeding. breeding.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.300-300
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• 2006

Nondestructive nanostructural analysis is indispensable in the development of nano-materials and nano-fabrication processes for use in nanotechnology applications. In this paper, we demonstrate for the first time a quantitative, nondestructive analysis of nanostructured thin films supported on substrates and their templated nanopores by using grazing incidence X-ray scattering and data analysis with a derived scattering theory. Our analysis disclosed that vertically oriented nanodomain cylinders had formed in 20-100 nm thick films supported on substrates consisting of a mixture of poly(styrene-b-methyl methacrylate) (PS-b-PMMA) and PMMA homopolymer, and that the PMMA nanodomains were selectively etched out by ultraviolet light exposure and a subsequent rinse with acetic acid, resulting in a structure consisting of hexagonally packed cylindrical nanopores.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.41.1-41.1
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• 2012

Interactions between the galactic interstellar medium (ISM) and the intra cluster medium (ICM) are believed to be one of the main processes affecting galaxy evolution in cluster environments. The aim of our research is to study the molecular gas properties of a galaxy under the ICM pressure in the cluster environment. It has been well known that cluster galaxies are deficient in atomic hydrogen gas (HI gas) compared to their field counterparts and now there is much evidence that low density ISM is being removed by ram pressure due to ICM wind. Meanwhile, no significant molecular gas deficiency of the cluster galaxy population has been found yet they show overall lower star formation rate than galaxies in the field, and it is still puzzling how the star formation could decrease without stripping of dense molecular gas. To address this issue, we probe the detailed molecular gas properties of NGC 4402, located near the cluster center, as part of a study of four spiral galaxies in the Virgo Cluster. NGC 4402 is well known undergoing ram pressure stripping with a truncated HI disk($D_{HI}/D_{opt}$ - 0.75 and only 36% of HI gas compare to field galaxies of a similar size) and a disturbed gas morphology. Comparing the high resolution 12CO and 13CO data of NGC 4402 from the Sub Millimeter Array (SMA) with existing other wavelength data, we probe the spatial distribution and a physical condition of molecular gas under strong ICM pressure. We discuss the star formation activity might have been altered and hence how the global color of NGC4402 would change in the future.

• BMB Reports
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• v.40 no.3
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• pp.349-357
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• 2007

The ubiquitous family of 14-3-3 proteins functions as regulators in a variety of physiological processes. Eight rice 14-3-3 genes, designated OsGF14a through h, were identified from an exhaustive search of the genome database. Comparisons of deduced amino acid sequences reveal a high degree of identity among members of the OsGF14 family and reported Arabidopsis 14-3-3 proteins. A phylogenetic study indicates that OsGF14s contain both $\varepsilon$ and non-$\varepsilon$ forms, which is also confirmed by a structural analysis of OsGF14 genes. Furthermore, transcripts of OsGF14b, OsGF14c, OsGF14d, OsGF14e, OsGF14f and OsGF14g were detected in rice tissues. Their different expression patterns, the different effects of environmental stresses and plant hormones on their transcription levels, and the different complementary phenotypes in yeast 14-3-3 mutants not only indicates that OsGF14s are responsive to various stress conditions and regulated by multiple signaling pathways, but also suggests that functional similarity and diversity coexist among the members of OsGF14 family.

• Molecular & Cellular Toxicology
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• v.5 no.3
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• pp.179-186
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• 2009

Hexachlorobenzene (HCB) is a bioaccumulative, persistent, and toxic pollutant. HCB is one of the 12 priority of Persistent Organic Pollutants (POPs) intended for global action by the United Nations Environment Program (UNEP) Governing Council. POPs are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Some of HCB is ubiquitous in air, water, soil, and biological matrices, as well as in major environmental compartments. HCB has effects on various organs such as thyroid, bone, skin, kidneys and blood cells and especially, revealed strong toxicity to liver. In this study, we identified genes related to hepatotoxiciy induced by HCB in human hepatocellular carcinoma (HepG2) cells using microarray and gene ontology (GO) analysis. Through microarray analysis, we identified 96 up- and 617 down-regulated genes changed by more than 1.5-fold by HCB. And after GO analysis, we determined several key pathways which known as related to hepatotoxicity such as metabolism of xenobiotics by cytochrome P450, complement and coagulation cascades, and tight junction. Thus, our present study suggests that genes expressed by HCB may provide a clue for hepatotoxic mechanism of HCB and gene expression profiling by toxicogenomic analysis also affords promising opportunities to reveal potential new mechanistic markers of toxicity.

• Molecules and Cells
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• v.38 no.1
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• pp.40-50
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• 2015

In the interaction between plants and pathogens, carbon (C) resources provide energy and C skeletons to maintain, among many functions, the plant immune system. However, variations in C availability on pathogen associated molecular pattern (PAMP) triggered immunity (PTI) have not been systematically examined. Here, three types of starch mutants with enhanced susceptibility to Pseudomonas syringae pv. tomato DC3000 hrcC were examined for PTI. In a dark period-dependent manner, the mutants showed compromised induction of a PTI marker, and callose accumulation in response to the bacterial PAMP flagellin, flg22. In combination with weakened PTI responses in wild type by inhibition of the TCA cycle, the experiments determined the necessity of C-derived energy in establishing PTI. Global gene expression analyses identified flg22 responsive genes displaying C supply-dependent patterns. Nutrient recycling-related genes were regulated similarly by C-limitation and flg22, indicating re-arrangements of expression programs to redirect resources that establish or strengthen PTI. Ethylene and NAC transcription factors appear to play roles in these processes. Under C-limitation, PTI appears compromised based on suppression of genes required for continued biosynthetic capacity and defenses through flg22. Our results provide a foundation for the intuitive perception of the interplay between plant nutrition status and pathogen defense.

• BMB Reports
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• v.53 no.5
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• pp.241-247
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• 2020

As an intracellular degradation system, autophagy is an essential and defensive cellular program required for cell survival and cellular metabolic homeostasis in response to various stresses, such as nutrient deprivation and the accumulation of damaged organelles. In general, autophagy flux consists of four steps: (1) initiation (formation of phagophore), (2) maturation and completion of autophagosome, (3) fusion of autophagosomes with lysosomes (formation of autolysosome), and (4) degradation of intravesicular components within autolysosomes. The number of genes and reagents that modulate autophagy is increasing. Investigation of their effect on autophagy flux is critical to understanding the roles of autophagy in many physiological and pathological processes. In this review, we summarize and discuss ways to analyze autophagy flux quantitatively and qualitatively with the use of imaging tools. The suggested imaging method can help estimate whether each modulator is an inhibitor or a promoter of autophagy and elucidate the mode of action of specific genes and reagents on autophagy processes.