• Journal of Life Science
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• v.20 no.6
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• pp.853-860
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• 2010

The DevSR two-component system is a major regulatory system involved in redox sensing in Mycobacterium smegmatis. The DevSR system consists of the DevS histidine kinase and its cognate DevR response regulator. When exposed to hypoxic conditions, the DevS histidine kinase is activated to phosphorylate the DevR response regulator, leading to the transcriptional activation of the DevR regulation. The ligand-binding state of the heme embedded in the N-terminal GAF domain of DevS determines the kinase activity of DevS. In this study, we demonstrated that the redox-responsive cysteine (C547) in the C-terminal kinase domain is involved in the redox-dependent control of DevS kinase activity. The formation of an intersubunit disulfide bond between the C547 residues in the presence of $O_2$ led to inactivation of DevS kinase activity. The reduction of the oxidized DevS with reductants such as $\beta$-mercaptoethanol and dithiothreitol resulted in the restoration of DevS kinase activity. It was demonstrated in vivo by complementation test that the substitution of C547 to alanine partially impaired the sensory function of DevS in M. smegmatis.

• Journal of Life Science
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• v.24 no.1
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• pp.54-60
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• 2014

Aromatic hydrocarbons are toxic environmental pollutants that are detrimental to the ecosystem and human health. Among them, chlorotoluene and nitrotoluene are toxic to hydrobios and irritate the skin, eyes, and respiratory organs of humans. We herein report the development of recombinant microbial biosensors for cheap and rapid monitoring of chlorotoluene and nitrotoluene compounds. Plasmids were constructed by inserting the xylR regulatory gene for BTEX (benzene, toluene, ethylbenzene, and xylene) degradation into upstream of Po' (the DmpR activator promoter Po with the deletion of its own upstream activating sequences) or Pu (the cognate promoter of XylR)::lacZ (the ${\beta}$-galactosidase gene) and transformed into Escherichia coli $DH5{\alpha}$. In the presence of inducers, the biosensor cells immobilized in agarose developed a red color in 1-2 h due to the hydrolysis of chlorophenol red ${\beta}$-D-galactopyranoside (CPRG), a substrate of ${\beta}$-galactosidase that was expressed by the inducers. Among BTEX, high responses were specifically observed with o-, m-, p-chlorotoluene ($0.1{\mu}M-100 mM$) and o-, m-, p-nitrotoluene (0.1 mM-100 mM). Po' demonstrated higher responses than those with Pu. The biosensors immobilized in agarose showed good stability after 21 days' storage at $4^{\circ}C$, and responses in untreated wastewater spiked with chlorotoluene and nitrotoluene, suggesting they can be used to detect compounds in wastewater.

• Korean Journal of Environment and Ecology
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• v.27 no.4
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• pp.449-461
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• 2013

This study is contributed to examine the vegetation characteristics of the Quercus mongolica which are located in between two summits, hyangnobong and gitdaebaggybong, with dividing two regions(I, II). A total of 63 Quercus mongolica communities were enrolled in this survey. A~E, 5 communities were the result of analysed classification by TWINSPAN. Spatial distribution of the communities; 'A' community is concentrated at an altitude of about 1,300 meters in Mt. Taebaek(II region). 'B' and 'C' communities are concentrated at an altitude of between 700 and 1500 meters in Mt. Seorak and Odae(Iregion). 'D' and 'E' communities are concentrated at an altitude of below 1,100 meters in Mt. Cheongok and geumdaebong(II region), and also Mt. Seorak and Odae(Iregion). Arboral and shrub populations, maximum species diversity and height of arboral of each communities have a characteristic of decreasing according to increasing altitude gradually. And the result of studying on arboreal growth increment with up to 40-year-old trees, there is no special tendency with growth increment in the altitude of subnormal 1,100 meters, but there is a tendency that growth increment becomes lower in the altitude of more than 1,100 meters. In correlation analysis, it is -0.53 in the Quercus mongolica and Betula costata community at an altitude of over 1,000 meters, the correlation shows negative(-). It is +0.59 in the Quercus mongolica and Rubus crataegifolius community at an altitude of less than 1,000 meters, the correlation shows positive(+). And those are cognate trees with the correlation of Betula costata, Betula costata Trautv., Tripterygium regelii Sprague&Takeda., Acer barbinerve Maxim. With a summary of the results, the changes in the environment according to the elevation affect Quercus mongolica community.

• Journal of Life Science
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• v.17 no.6 s.86
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• pp.783-790
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• 2007

G protein coupled receptors (GPCRs) transmit various extracellular signals into the cells. Upon binding of the ligands, conformational changes in the extracellular and/or transmembrane (TM) domains of CPCRs were propagated into the cytoplasmic (CP) domain of the molecule leading to the activation of their cognate heterotrimeric C proteins and kinases. Constitutively active GPCR mutants causing the activation of C Protein signaling even in the absence of ligand binding are of interest for the study of activation mechanism of GPCRs. Two classes of constitutively active mutations, categorized by their effects on the salt bridge between Ell3 and K296, were found in the TM domain of rhodopsin. Opsin mutants containing combinations of the mutations were constructed to study the conformational changes required for the activation of rhodopsin. Rhodopsin chromophore regenerated with 11-cis-retinal showed a thermal stability inversely correlated with its constitutive activity. In contrast, rhodopsin mutants exhibited a binding affinity to an agonist, all-trans-retinal, in a constitutive activity-dependent manner. In order to test whether the conformational changes responsible for the activation of trans-ducin (Gt) are the same as the conformation required for the recognition of rhodopsin kinase, analysis of the mutants were carried out with phosphorylation by rhodopsin kinase. Rhodopsin mutants containing combinations of different classes of the mutations showed a strong synergistic effect on the phosphorylation of the mutants in the dark as similar to that of Gt activation. The results suggest that at least two or three kinds of segmental and independent conformational changes are required for the activation of rhodopsin and the conformational changes responsible for activating rhodopsin kinase and Gt are similar to each other.

• Journal of the Mineralogical Society of Korea
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• v.18 no.1
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• pp.33-43
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• 2005

Three types of clinopyroxenes in alkali basaltic rocks from Jeju Island can be identified on the basis of geochemical and textural data. Type Ⅰ is Cr-rich diopside in spinel peridotites from the upper mantle. Type Ⅱ is augite in fine-grained pyroxenites which are possibly either magmatic vein or metamorphic segregations owing to anatexis of the upper mantle. The augite of Type Ⅱ contains high Ca and Mg and relatively low Ti. Type Ⅲ is thought to be either cumulates or cognate phenocrysts and can be subdivided into Ⅲa, Ⅲb, and Ⅲc based on their occurrence mode. Clinopyroxenes of Type Ⅰ have the highest Mg# and Si and the lowest Ti, whereas those of Type Ⅲhave lower Mg#와 Si and higher Ti. These geochemical characteristics indicate that (Ti+Al/sup Ⅵ/)/Si and Al/sup Ⅵ//Al/sup Ⅵ/ increase from Type Ⅰ to Type Ⅲ. It is possibly interpreted that Type Ⅰ is of the highest pressure origin and Type Ⅲ of the lowest. Fractionation of high-pressure clinopyroxenes would result in evolved undersaturated alkali-enriched liquids, probably producing the alkali-enriched host basaltic rocks in Jeju Island.

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.281-288
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• 2011

To screen downstream genes of Aspergillus nidulans MsnA showing amino acid sequence similarity to the zinc finger region of Msn2/4 stress response transcription factors in Saccharomyces cerevisiae, differentially expressed genes (DEG) in MsnA overexpressed or msnA null mutant strains compared to wild type have been isolated. The cognate gene IDs were identified by DNA sequencing of the selected DEGs. Among those, DEG6 was known as mstB encoding a putative monosaccharide transporter. Expression level of mstB mRNA was increased in MsnA overproducing strains and MsnA bound directly to the promoter region of mstB in vitro. MstB containing twelve transmembrane domains exhibited 80% of amino acid sequence identities to A. niger MstA a high-affinity monosaccharide transporter. A null mutant of mstB was phenotypically undistinguishable to wild type. On the other hand, forced overexpression of MstB caused the increased formation of sexual structure cleistothecia in 0.1% glucose condition where wild type showed almost no cleistothecia. This result implies that mstB is involved in transport of monosaccharide required for sexual differentiation.

• Journal of Life Science
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• v.23 no.11
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• pp.1409-1414
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• 2013

Lymph node (LN) is the sites where mature lymphocytes become stimulated to respond to invading pathogens in the body. Lymphocytes screen the surfaces of pathogen-carrying antigen-presenting cells for cognate antigens, while moving along stromal structural back bone. Fibroblastic reticular cells (FRC) is stromal cell forming the 3 dimensional structure networks of the T cell rich zones in LN, and provide a guidance path for immigrating T lymphocytes. In these cooperative environments, the cell to cell bidirectional interactions between FRC and T cells in LN are therefore essential to the normal functioning of these tissues. Not only do FRCs physically construct LN architecture but they are essential for regulating T cell biology within these domains. FRC interact closely with T lymphocytes, is providing scaffolds, secreting soluble factors including cytokine in which FRCs influence T cell immune response. More recently, FRC have been found to induce peripheral T cell tolerance and regulate the extent to which newly activated T cells proliferate within LN. Thus, FRC-T cell crosstalk has important consequences for regulating immune cell function within LN. In addition, FRC have profound effects on innate immune response by secreting anti-microbial peptides and complement, etc in the inflammatory milieu. In summary, we propose a model in which FRC engage in a bidirectional touch to increase the T cell biological efficiency between FRC and T cells. This collaborative feedback loop may help to maintain tissue function during inflammation response.

• The Journal of the Petrological Society of Korea
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• v.25 no.3
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• pp.299-310
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• 2016

The Stele for Buddhist Monk Wonjong at Godalsa Temple Site was destroyed a long time ago. Only the tortoise-shaped pedestal and the ornamental capstone in the form of a hornless dragon remain at the site and the broken stele body is stored at the National Museum of Korea today. The stele is made of two kinds of rocks that are coarse-grained biotite granite for the pedestal and the capstone, and fine-grained biotite granite including hornblende assemblages and feldspar phenocrysts for the stele body. The coarse-grained biotite granite of the pedestal and capstone showed same magnetic susceptibility and lithological characteristics with biotite granite outcrops in Yeoju area, whereas the fine-grained granite of the stele body did not. To find a provenance of the stele body stone, we investigated Korean granites in terms of magnetic susceptibility, lithology and old recordings about construction process of the stele. As a result, Haeju granite is the most likely to be a cognate rock of the stele body stone as it has same texture and lithological characteristics like color, hornblende assemblages, mineral composition and magnetic susceptibility. It is imported from Haeju (North Korea) to South Korea via China commercially, and the most suitable for a replica stone of the stele body.

• Cross-Cultural Studies
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• v.50
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• pp.425-451
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• 2018

In this paper, we examined the issues of the discussions on the subject of doublets. In general, as a definition, the use of doublets refer to a pair of words which have a common etymon, but also to a pair of words or grammatical morphemes that have the same meaning and similar forms of the word. In this paper, we have seen that a typical pairing word is a pair of words with a common etymology. Generally speaking, it is possible to divide doublets into subtypes depending on the identified similarities or differences in the meaning or form. The most distant type from the typical type of doublets is a pair of words that do not have a common etymon, but have the same meaning and are similar in form. The second issue about doublets is whether doublets include only words. For example, if some josas (postpositions or particles) have a common etymon, then it is noted that they can be accepted as a kind of doublets. In the case of suffixes, it may be possible to recognize the suffixes as doublets if they have a common etymon. In other words, it is not necessary to recognize the suffixes as doublets because the derivatives which are derived by the suffixes can be accepted as doublets. In the case of endings, it may be possible to recognize a pair of endings which have the same meaning and the common etymon as a doublet. Otherwise, the word forms to which the endings are combined can be accepted likewise as doublets. However, considering the fact that the endings typically in use in the Korean language may have syntactic properties, the endings should be considered as doublets rather than the words which have the endings. Finally, we conclude that there may be some debate as to whether stem doublets or ending doublets belong to a lexical item in the lexicon. It can be said that they are plural underlying forms and may be deserving of further research.

• Cross-Cultural Studies
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• v.46
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• pp.355-377
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• 2017

Compared with other Altaic languages, Japanese and Korean languages are much closer to each other in grammar, and also to Ryukyuan language. According to the literature, Korean people are the first foreigners to record Ryukyuan language in a written form. In the passage "pronunciation interpreting the Ryukyuan Kingdom" from A Journey to the Eastern Countries (1512), Korean people perfectly preserved the pronunciation and meanings of words and sentences in Ryukyuan language in both Korean and Chinese languages, which is an extremely valuable material. Unfortunately, the later time period witnessed stagnation after a prominent beginning. In order to clarify the language family to which Korean belongs to, it is necessary to thoroughly compare Korean language with Japanese and Ryukyuan languages. Different from lexis, grammar underwent a slow and gradual process of variation. A comparative study of the three languages can provide strong evidence for defining the language family of Korean. Based on this rationale, this paper starts from the comparison of grammar elements of these three languages, aiming at case markers including the nominative case markers and the accusative case markers, and observes the procedures and functions diachronically. Based on the examples from the medieval data, it is found that the nominative case markers and the accusative case markers of these three languages vary from each other in forms and origins. Although they show some similarities in functions, it can be conjectured that there is no cognate for the three languages in the history.