• 공업화학
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• 제26권1호
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• pp.86-91
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• 2015

BHT (2,6-di-tert-butyl-4-methylphenol), TBC (4-tert-butylcatechol), 스테아린산구리 등 여러 가지 중합방지제를 사용하여 MPPO (3-methyl-1-phenyl-2-phospholene-1-oxide)를 제조하였다. 제조한 시료에 대해 FTIR, $^1H$-NMR, GC/MS 등을 이용하여 분석한 결과 중합방지제의 종류에 관계없이 MPPO 합성이 확인되었다. 반응 시간이 증가하면 MPPO의 수율은 증가하지만, 순도는 약간 저하하는 경향을 보였다. 합성 온도가 높아지면 MPPO의 수율과 순도가 증가하였지만, 스테아린산구리를 사용한 경우 MPPO의 순도 변화는 나타나지 않았다. 중합방지제 양이 증가하면 MPPO의 수율은 변화가 나타나지 않았다. 순도는 중합방지제 양이 증가하면 증가하였지만, BHT를 사용한 경우에는 중합방지제 양에 따른 MPPO의 순도 변화가 없었다. Diphenylcarbodiimide 합성에 대한 MPPO의 촉매 활성은 스테아린산구리를 사용하여 제조한 MPPO가 가장 높았다.

• 공업화학
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• 제5권3호
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• pp.425-430
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• 1994

2-Hydroxyethyl methacrylate(2-HEMA)의 합성에 있어서 중합억제제와 촉매의 영향에 대해서 조사하였다. 촉매로서 triethylamine(TEA), $FeCl_3{\cdot}6H_2O$, $Cu(NO_3)_2$, $2H_2O$, $AlCl_3$, $Na_2Cr_2O_7$을 선택하였으며, 중합억제제로는 p-Methoxyphenol(PMP) 또는 $NaNO_3$ 수용액을 각각 사용하였다. $NaNO_3$ 수용액을 중합억제제로 사용한 경우, triethylamine(TEA), $FeCl_3{\cdot}6H_2O$, $Na_2Cr_2O_7$는 좋은 촉매 효과를 보여 주었다. p-Methoxyphenol(PMP)를 중합억제제로 사용한 경우, 반응은 매우 느렸고 PMP가 $Fe^{3+}$ 또는 $Cr^{6+}$ 이온을 환원시키기 때문에 효과적이지 못했다. 이와는 달리, $NaNO_3$ 수용액을 중합억제제로 사용한 경우, 반응은 매우 빨랐으며 금속 촉매의 비활성화도 없었다.

• International Journal of Oral Biology
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• 제46권3호
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• pp.99-104
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• 2021

Associations between periodontal infection and cardiovascular disease have been documented. Porphyromonas gingivalis is a well-established periodontal pathogen, and tissue factor (TF) is a key initiator of the coagulation cascade. In this context, P. gingivalis has been reported to enhance TF expression in human endothelial cells. The present study investigated the underlying mechanisms of TF induction by P. gingivalis in human umbilical vein endothelial cells. P. gingivalis increased TF expression in a dose- and time-dependent manner. Not only live bacteria but also glutaraldehyde-fixed bacteria increased TF expression to the same extent. However, sonicates of P. gingivalis did not induce TF expression. Cytochalasin D and SMIFH2, which are inhibitors of actin polymerization and actin nucleation, respectively, inhibited the TF expression induced by P. gingivalis. Finally, TF production was decreased or increased in the presence of various signaling inhibitors, including mitogen-activated protein kinases. These results suggest that P. gingivalis induces endothelial TF expression by a bacterial internalization-dependent mechanism and through diverse signal transduction mechanisms.

• Journal of Periodontal and Implant Science
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• 제35권2호
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• pp.427-436
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• 2005

Objective: MMP-8 is a neutrophil enzyme and its level increases in some inflammatory diseases, including periodontal disease. We knew that the lipopolysaccharide of E.coli(E-LPS) induced MMP-8 release from human neutrophils. E-LPS is known to induce the production and release of inflammatory cytokines through CD14, Toll-like receptor(TLR). In the present study, we investigated whether MMP-8 release by E-LPS is induced via CD14-TLR pathway and the cellular mechanism of MMP-8 release in human neutrophils. Material and methods: Human neutrophils were isolated from the peripheral blood of healthy donors and pre-incubated in medium containing antibodies against CD14, anti-TLR2 and anti-TLR4 or several inhibitors of microtubules and microfilaments and then incubated with E-LPS. The cells were treated TPCK and E-LPS simultaneously. The MMP-8amount in the culture medium was determined using ELISA. Results: E-LPS increased MMP-8release from neutrophils and its induction was inhibited by anti-CD14 and anti-TLR4 but not by anti-TLR2 antibodies. The inhibitors of microtubule and microfilament polymerization significantly decreased E-LPS-induced MMP-8release. TPCK inhibited E-LPS-induced MMP-8 release. Conclusion: These results suggest that MMP-8 release is induced by E-LPS via the CD14-TLR4 signal pathway in human neutrophils and may be depedent on microtubule and microfilament systems and $NF-{\kappa}B$ pathway.

• 생명과학회지
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• 제18권7호
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• pp.952-957
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• 2008

본 실험에서는 THP-1 세포의 PMA에 의하여 유도되는 초기 세포부착에 관한 메카니즘을 이해하기 위하여 다양한 요인(혈청, 신규 단백질의 합성, 세포 골격 저해제, 단백질 인신화 저해제)들의 효과를 조사하였다. 또한 본 실험에서는 이들 세포부착의 정도를 일반적으로 세포증식 분석에 사용되고 있는 SRB염색법을 도입하여 세포부착 분석에 간편한 방법의 조건을 확립하였다. PMA에 의한 초기 세포부착에는 배양액중의 혈청의 유무는 영향이 없었으나, 신규 단백질의 합성이 요구되는 것을 확인하였다. 또한 이들 초기 세포부착에 PMA처리에 의한 PKC의 활성화는 필수적이나, 그 하류 활성화 인자로 잘 알려진 MAP-kinase (erk1/2)의 인산화는 필요치 않음을 알 수 있었다. 흥미롭게도 액틴 중합 저해제인 cytochalasin D의 PMA와 공 처리는 오히려 세포부착을 PMA 단독 처리시 보다 증가시켰다. 또한 본 실험에서 사용된 SRB 염색법을 통한 세포부착 분석법은 최근 암 등 다양한 질환의 신약 표적 분자로 주목을 받고 있는 PKC 저해제의 초기 세포 기반 분석에 매우 유용하리라고 생각된다.

• International Journal of Oral Biology
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• 제39권3호
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• pp.131-136
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• 2014

Porphyromonas gingivalis is one of the most important periodontal pathogens and has been to known to invade various types of cells, including endothelial cells. The present study investigated the mechanisms involved in the internalization of P. gingivalis in human umbilical vein endothelial cells (HUVEC). P. gingivalis internalization was reduced by clathrin and lipid raft inhibitors, as well as a siRNA knockdown of caveolin-1, a principal molecule of lipid raft-related caveolae. The internalization was also reduced by perturbation of actin rearrangement, while microtubule polymerization was not required. Furthermore, we found that Src kinases are critical for the internalization of P. gingivalis into HUVEC, while neither Rho family GTPases nor phosphatidylinositol 3-kinase are required. Taken together, this study indicated that P. gingivalis internalization into endothelial cells involves clathrin and lipid rafts and requires actin rearrangement associated with Src kinase activation.

• Journal of Microbiology and Biotechnology
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• 제20권11호
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• pp.1513-1520
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• 2010

A bacterium capable of producing melanin pigment in the presence of L-tyrosine was isolated from a crop field soil sample and identified as Klebsiella sp. GSK based on morphological, biochemical, and 16S rDNA sequencing. The polymerization of this pigment occurs outside the cell wall, which has a granular structure as melanin ghosts. Chemical characterization of the pigment particles showed then to be acid resistant, alkali soluble, and insoluble in most of the organic solvents and water. The pigment got bleached when subjected to the action of oxidants as well as reductants. This pigment was precipitated with $FeCl_3$, ammoniacal silver nitrate, and potassium ferricynide. The pigment showed high absorbance in the UV region and decreased absorbance when shifted towards the visible region. The melanin pigment was further charecterized by FT-IR and EPR spectroscopies. A key enzyme, 4-hydroxyphenylacetic acid hydroxylase, that catalyzes the formation of melanin pigment by hydroxylation of L-tyrosine was detected in this bacterium. Inhibition studies with specific inhibitors, kojic acid and KCN, proved that melanin is synthesized by the DOPA-melanin pathway.

• Molecules and Cells
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• 제21권3호
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• pp.330-336
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• 2006

Since its identification in 1989, hepatitis C virus has been the subject of extensive research. The biology of the virus and the development of antiviral drugs are closely related. The RNA polymerase activity of nonstructural protein 5B was first demonstrated in 1996. NS5B is believed to localize to the perinuclear region, forming a replicase complex with other viral proteins. It has a typical polymerase structure with thumb, palm, and finger domains encircling the active site. A de novo replication initiation mechanism has been suggested. To date, many small molecule inhibitors are known including nucleoside analogues, non-nucleoside analogues, and pyrophosphate mimics. NS5B interacts with other viral proteins such as core, NS3, 4A, 4B, and 5A. The helicase activity of NS3 seems necessary for RNA strand unwinding during replication, with other nonstructural proteins performing modulatory roles. Cellular proteins interacting with NS5B include VAMP-associated proteins, heIF4AII, hPLIC1, nucleolin, PRK2, ${\alpha}$-actinin, and p68 helicase. The interactions of NS5B with these proteins might play roles in cellular trafficking, signal transduction, and RNA polymerization, as well as the regulation of replication/translation processes.

• Bulletin of the Korean Chemical Society
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• 제32권11호
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• pp.3893-3898
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• 2011

Cellular uptake of double-stranded DNA (dsDNA) triggers strong innate immune responses via activation of NF-${\kappa}B$ transcription factor. However, the detailed mechanism of dsDNA-mediated innate immune response remains yet to be elucidated. Here, we show that the expression of tazarotene-induced gene 3 (TIG3) is dramatically induced by dsDNA stimulation, and the siRNA-mediated down-regulation of TIG3 mRNA results in significant suppression of dsDNA-triggered cytokine expression. Because TIG3 has been previously shown to physically interact with transglutaminase (TG) 1 to activate TG activity, and TG2 has been shown to induce NF-${\kappa}B$ activity by inducing $I{\kappa}B{\alpha}$ polymerization, we tested whether TG also plays a role in dsDNA-mediated innate immune response. Pre-treatment of TG inhibitors dramatically reduces dsDNA-triggered cytokine induction. We also show that, in HeLa cells, TG2 is the major TG, and TIG3 physically interacts with TG2. Combined together, our results suggest a novel mechanism of dsDNA-triggered innate immune response which is critically dependent on TIG3 and TG2.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권5호
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• pp.339-344
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• 2004

A method for synthesizing branched fructo-oligosaccharides (BFOS) with a high concentration of sucrose ($1{\~}3$ M) was developed using levansucrase prepared from Leuconortoc mesenteroides B-1355C. The degree of polymerization of oligosaccharides synthesized according to the present method ranged from 2 to over 15. The synthesized BFOS were stable at a pH ranges of 2 to 4 under $120^{\circ}C$. The percentage of BFOS in the reaction digest was $95.7\%$ (excluding monosaccharides; $4.3\%$ was levan). BFOS reduced the insoluble glucan formation by Streptococcus sobrinus on the surfaces of glass vials or stainless steel wires in the presence of sucrose. They also reduced the growth and acid productions of S, sobrinus. Oligosaccharides can be used as sweeteners for foods such as beverages requiring thermo- and acid-stable properties and 3s potential inhibitors of dental caries.