• Korea Journal of Cosmetic Science
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• v.1 no.1
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• pp.1-9
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• 2019

The identification of compounds with anti-senescence activity in cell culture system is a first step in aging research. Given that pyruvate can be used energy source by conversion to acetyl-CoA in mitochondria, and protects cultured cell from various stress-induced cell damage and cell death, synthetic media (e.g., DMEM) often includes 1 mM pyruvate, which is very higher than the pyruvate concentration in human blood (approximately 30 ��M). However, the use of medium containing high concentration of pyruvate is not suitable for screening anti-senescence compounds, because pyruvate also protects against the cellular senescence of primary human dermal fibroblasts (NHDFs) through NAD+ generated during conversion to lactate. In this study, four extracts, i.e., Sprouted seed and fruit complex, Poncirus trifoliata fruit extract, Jaum balancing complex, and Prunus mume extract were used for evaluation of different anti-senescence effect in the absence or presence of 0.1 mM pyruvate, similar to the physiological pyruvate concentration. The senescence in NHDFs cultured with DMEM in the presence of 0.1 mM pyruvate (approximately the physiological concentration in human blood) is accelerated, as observed in pyruvate deprivation conditions. The cytotoxicity of the Poncirus trifoliata fruit extract was protected by pyruvate, and Jaum balancing complex and Prunus mume extract had anti-senescence activity in the presence of 0.1 mM pyruvate, but not in the absence of pyruvate. Given that pyruvate is a powerful protector against both cytotoxicity and cellular senescence, the screening of candidate agents for anti-senescence in high pyruvate conditions using an in vitro cell culture system is not valid. Therefore, we recommend the use of a low concentration of pyruvate to evaluate the anti-senescence effects of candidates, which is more similar to in vivo aging conditions than excessive stress-induced senescence models, to exclude the effect of excessive pyruvate in vitro.

• International Journal of Oral Biology
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• v.46 no.4
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• pp.190-199
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• 2021

Despite evidence that bacteria-sensing Toll-like receptors (TLRs) are activated in salivary gland tissues of Sjogren syndrome (SS) patients, the role of oral bacteria in SS etiopathogenesis is unclear. We previously reported that two SS-associated oral bacteria, Prevotella melaninogenica (Pm) and Rothia mucilagenosa (Rm), oppositely regulate the expression of major histocompatibility complex class I (MHC I) in human salivary gland (HSG) cells. Here, we elucidated the mechanisms underlying the differential regulation of MHC I expression by these bacteria. The ability of Pm and Rm to activate TLR2, TLR4, and TLR9 was examined using TLR reporter cells. HSG cells were stimulated by the TLR ligands, Pm, and Rm. The levels of MHC I expression, bacterial invasion, and viability of HSG cells were examined by flow cytometry. The hypoxic status of HSG cells was examined using Hypoxia Green. HSG cells upregulated MHC I expression in response to TLR2, TLR4, and TLR9 activation. Both Pm and Rm activated TLR2 and TLR9 but not TLR4. Rm-induced downregulation of MHC I strongly correlated with bacterial invasion and cell death. Rm-induced cell death was not rescued by inhibitors of the diverse cell death pathways but was associated with hypoxia. In conclusion, Pm upregulated MHC I likely through TLR2 and TLR9 activation, while Rm-induced hypoxia-associated cell death and the downregulation of MHC I, despite its ability to activate TLR2 and TLR9. These findings may provide new insight into how oral dysbiosis can contribute to salivary gland tissue damage in SS.

• Journal of the Korean Ceramic Society
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• v.33 no.3
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• pp.293-298
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• 1996

Room temperature Li+ ion conductivities of Li3xLa(2/3-x)TiO3 system with x=0.117~0.317 were measured by complex impedance method. ICP, SEM and XRD analysis were conducted to study the main factor which influence the Li+ ion conductivity. Li+ ion conductivity seems to have a close relationship with the crystal structure of primitive cell increase as the primitive cell as close to cubic.

• Biomolecules & Therapeutics
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• v.20 no.4
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• pp.371-379
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• 2012

Prebiotic oligosaccharides, with a degree of polymerization (DP) of mostly less than 10, exhibit diverse biological activities that contribute to human health. Currently available prebiotics are mostly derived from disaccharides and simple polysaccharides found in plants. Subtle differences in the structures of oligosaccharides can cause significant differences in their prebiotic properties. Therefore, alternative substances supplying polysaccharides that have more diverse and complex structures are necessary for the development of novel oligosaccharides that have actions not present in existing prebiotics. In this review, we show that structural polysaccharides found in plant cell walls, such as xylans and pectins, are particularly potential resources supplying broadly diverse polysaccharides to produce new prebiotics.

• Bulletin of the Korean Chemical Society
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• v.20 no.8
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• pp.925-928
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• 1999

The process of transcription is the major point at which gene expression is regulated. The jun and fos families of eukaryotic transcription factor heterodimerize to form complexes capable of binding 5'-TGAGTCA-3'DNA elements (AP-1 binding site). To search for the inhibitors of the jun-fos-DNA complex formation, several natural products extracts were screened and methanol extract of tanshen (the dried roots of Salvia miltiorrhiza Bunge) showed remarkable inhibitory activity. The active compounds of the extracts were purified using re-peated column chromatography and recrystallization. Their structures were identified as tanshinone I and tanshinone IIA. Through the electrophoresis mobility shift assay and cell cytotoxicity test, tanshinone I and tanshinone IIA were identified as inhibitors that suppress not only AP-1 function but also the cell proliferation. Tanshinone I also suppressed the jun-fos-DNA complex formation in TPA-induced NIH 3T3 cells.

• Molecules and Cells
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• v.44 no.5
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• pp.328-334
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• 2021

The advent of the major histocompatibility complex (MHC) multimer technology has led to a breakthrough in the quantification and analysis of antigen-specific T cells. In particular, this technology has dramatically advanced the measurement and analysis of CD8 T cells and is being applied more widely. In addition, the scope of application of MHC multimer technology is gradually expanding to other T cells such as CD4 T cells, natural killer T cells, and mucosal-associated invariant T cells. MHC multimer technology acts by complementing the T-cell receptor-MHC/peptide complex affinity, which is relatively low compared to antigen-antibody affinity, through a multivalent interaction. The application of MHC multimer technology has expanded to include various functions such as quantification and analysis of antigen-specific T cells, cell sorting, depletion, stimulation to replace antigen-presenting cells, and single-cell classification through DNA barcodes. This review aims to provide the latest knowledge of MHC multimer technology, which is constantly evolving, broaden understanding of this technology, and promote its widespread use.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.132.1-132.1
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• 2003

Novel trans-ditrifluoroacetato, malonato-1, 4-butanediamine Pt(IV) complex, K104 was synthesized as a chemotherpeutic. The cytotoxicity of K104 against various human cancer cell lines were evaluated by MTS assay in vitro. The IC50 values of K104 ranged 15.83-25.83 $\mu\textrm{M}$, compared to CBCDA ranged 23.24-69.6 $\mu\textrm{M}$. Among several cancer cell lines, K104 showed more potent than CBCDA in colon cancer cell lines. (omitted)

• Molecules and Cells
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• v.27 no.6
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• pp.697-701
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• 2009

We previously identified cancer-upregulated gene 2 (CUG2) as a commonly up-regulated gene in various human cancer tissues, especially in ovary, liver, and lung (Lee et al., 2007a). CUG2 was determined to be a nuclear protein that exhibited high proto-oncogenic activities when overexpressed in NIH3T3 mouse fibroblast cells. To identify other cellular functions of CUG2, we performed yeast two-hybrid screening and identified CENP-T, a component of CENP-A nucleosome complex in the centromere, as an interacting partner of CUG2. Moreover, CENP-A, the principle centromeric determinant, was also found in complex with CENP-T/CUG2. Immunofluorescent staining revealed the co-localization of CUG2 with human centromeric markers. Inhibition of CUG2 expression drastically affected cell viability by inducing aberrant cell division. We propose that CUG2 is a new component of the human centromeric complex that is required for proper chromosome segregation during mitosis.

• Macromolecular Research
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• v.14 no.3
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• pp.267-271
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• 2006

Polyelectrolyte complex films were prepared with two compounds, chitosan and poly(ethylene glycol)-monosuccinate, using a casting in order to synthesize a polyelectrolyte complex film with various mole ratios of chitosan and poly(ethylene glycol)-monosuccinate. The solution properties of isolated PEC were investigated for the effects of FTIR, pH value, Brookfield viscosity and cell viability assay using MTT staining. The PEC films were evaluated for mechanical properties by typical stress-strain curve, far thermal properties by DSC and TGA and for surface morphology Properties by SEM. Furthermore, the surface resistance, moisture regain and water content of the films were characterized. The solution properties were affected by several factors including the chitosan content in the PEC, the mixing ratio of PEG and chitosan, and pH. Several PEC in acidic conditions exhibited film formation under appropriate conditions of mixing ratio and chitosan concentration in the mixing process. These PEC films were found to have sufficiently flexible and stable properties due to their hydrophilic structure, which was farmed by the oppositely charged interaction between PEG-MS and chitosan matrix. The results showed the potential applicability of chitosan and poly(ethylene glycol)-monosuccinate films as a biocompatible polymer.

• Biodesign
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• v.6 no.4
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• pp.96-99
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• 2018

The gram-positive bacterium Staphylococcus aureus is a common cause of abscesses, sinusitis and food poisoning. The emergence of antibiotic-resistant strains has caused significant clinical issues worldwide. The HslU-HslV complex was first identified as a prokaryotic homolog of eukaryotic proteasomes. HslU is an unfoldase that mediates the unfolding of the substrate proteins, and it works with the protease HslV in the complex. To date, the protein complex has been mostly studied in gram-negative bacteria. In this study, we report the purification and crystallization of the full-length HslU from S. aureus. The crystal diffracted X-rays to a $3.5{\AA}$ resolution, revealing that the crystals belong to space group $P2_1$, with unit cell parameters of a = 166.5, b = 189.6, $c=226.6{\AA}$, and ${\beta}=108.1^{\circ}$. We solved the phage problem by molecular replacement using the structure of HslU from Haemophilus influenzae as a search model. The cell content analysis with this molecular replacement solution revealed that 24 molecules are contained in the asymmetric unit. This structure provides insight into the structural and mechanistic difference of the HslUV complex of gram-positive bacteria.