• BMB Reports
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• v.32 no.1
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• pp.45-50
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• 1999

We previously found three transcription factor-binding motifs in the rat p53 promoter. They are two recognition motifs of NF1-like protein (NF1-like element 1: -296 ~ -312, NF1-like element 2: -195 ~ -219) and a bHLH protein binding element (-142 ~ -146). In this study, we investigated the DNA-protein complex formation of the three elements with nuclear extracts from both normal and regenerating liver to find the element involved in the induced transcription of p53. The level of each DNA-protein complex on NF1-like and bHLH motifs was not changed. Instead, a new element located at -264 ~ -284 was detected in the DNase I footprinting assay with regenerating nuclear extract. This element has partial homology to the AP1 consensus motif. However, the competition studies with diverse oligonucleotides suggest that the binding protein is not AP1. An in vitro transcription assay shows that this element is important for the transcriptional activation of the rat p53 promoter. Therefore, for the induced transcription of the rat p53 promoter, the-264 ~ -284 region is required in addition to two NF1-like and one bHLH motif.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2263-2270
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• 2014

Solvolysis rate constants of 2-phenylethyl-(2-$PhCH_2CH_2OCOCl$, 1) and 2,2-diphenylethyl chloroformate (2,2-$Ph_2CHCH_2OCOCl$, 2), together with the previously studied solvolyses of ${\alpha}$- and ${\beta}$-substituted chloroformate ester derivatives, are reported in pure and binary solvents at $40.0^{\circ}C$. The linear free energy relationship (LFER) and sensitivities (l and m) to changes in solvent nucleophilicity ($N_T$) and solvent ionizing power ($Y_{Cl}$) of the solvolytic reactions are analyzed using the Grunwald-Winstein equation. The kinetic solvent isotope effects (KSIEs) in methanol and activation parameter values in various solvents are investigated for 1 and 2. These results support well the bimolecular pathway with same aspects. Furthermore, the small negative values of the entropies of activation of solvolysis of 1 and 2 in the highly ionizing aqueous fluoroalcohols are consistent with the ionization character of the rate-determining step, and the KSIE values of 1.78 and 2.10 in methanol-d indicate that one molecule of solvent acts as a nucleophile and the other acts as a general-base catalyst. It is found that the ${\beta}$-substituents in alkyl chloroformate are not the important factor to decide the solvolysis reaction pathway.

• Bulletin of the Korean Chemical Society
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• v.27 no.2
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• pp.231-236
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• 2006

A novel sample pretreatment technique, headspace hanging drop liquid phase microextraction (HS-LPME) was studied and applied to the determination of flavors from solid clove buds by gas chromatography-mass spectrometry (GC-MS). Several parameters affecting on HS-LPME such as organic solvent drop volume, extraction time, extraction temperature and phase ratio were investigated. 1-Octanol was selected as the extracting solvent, drop size was fixed to 0.6 $\mu$L. 60 min extraction time at 25 ${^{\circ}C}$ was chosen. HS-LPME has the good efficiency demonstrated by the higher partition equilibrium constant ($K_{lh}$) values and concentration factor (CF) values. The limits of detection (LOD) were 1.5-3.2 ng. The amounts of eugenol, $\beta$-caryophyllene and eugenol acetate from the clove bud sample were 1.90 mg/g, 1.47 mg/g and 7.0 mg/g, respectively. This hanging drop based method is a simple, fast and easy sample enrichment technique using minimal solvent. HSLPME is an alternative sample preparation method for the analysis of volatile aroma compounds by GC-MS.

• Journal of Applied Biological Chemistry
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• v.64 no.4
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• pp.323-331
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• 2021

Lincomycin is a lincosamide antibiotic isolated from the actinomycete Streptomyces lincolnensis. Moreover, it has been found to be effective against infections caused by Staphylococcus, Streptococcus, and Bacteroides fragillis. To identify the melanin-inducing properties of lincomycin, we used B16F10 melanoma cells in this study. The melanin content and intracellular tyrosinase activity in the cells were increased by lincomycin, without any cytotoxicity. Western blot analysis indicated that the protein expressions of tyrosinase, tyrosinase related protein 1 (TRP1) and TRP2 increased after lincomycin treatment. In addition, lincomycin enhanced the expression of master transcription regulator of melanogenesis, a microphthalmia-associated transcription factor (MITF). Lincomycin also increased the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and decreased the AKT phosphorylation. Moreover, the activation of tyrosinase activity by lincomycin was inhibited by the treatment with SB203580, which is p38 inhibitor. Furthermore, we also found that lincomycin-induced tyrosinase expression was reduced by H-89, a specific protein kinase A (PKA) inhibitor. These results indicate that lincomycin stimulate melanogenesis via MITF activation via p38 MAPK, AKT, and PKA signal pathways. Thus, lincomycin can potentially be used for treatment of hypopigmentation disorders.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.878-883
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• 2018

A circulating fluidized bed (CFB) has been used in various chemical industries because of good heat and mass transfer. In addition, the methanol to olefins (MTO) process requiring the CFB reactor has attracted a great deal of interest due to steep increase of oil price. To design a CFB reactor for MTO pilot process, therefore, we has examined the hydrodynamic properties of spherical catalysts with different particle size and developed a correlation equation to predict catalyst holdup in a riser of CFB reactor. The hydrodynamics of micro-spherical catalysts with average particle size of 53, 90 and 140 mm was evaluated in a $0.025m-ID{\times}4m-high$ CFB riser. We also developed a model described by a decay coefficient to predict solid hold-up distribution in the riser. The decay coefficient developed in this study could be expressed as a function of Froude number and dimensionless velocity ratio. This model could predict well the experimental data obtained from this work.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 1996.04a
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• pp.27-27
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• 1996

• Korean Journal of Environmental Agriculture
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• v.13 no.2
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• pp.209-215
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• 1994

Absorption, translocation, and metabolism of the herbicide alachlor in soybean, Chinese cabbage, and barnyard grass seedlings were examined and compared with each other using [phenyl-U-$^{14}C$] alachlor in search of a primary factor contributing to the selectivity of alachlor. When root of each seedling was immersed into the solution containing [$^{14}C$]alachlor, the amount of absorbed radioactivity/mg dry matter of seedling which was suggested to be correlated with the susceptibility of plants to alachlor decreased in the order of soybean ${\gg}$ Chinese cabbage ${\geq}$ barnyard grass and the rate of translocation to shoot was Chinese cabbage ${\geq}$ barnyard grass ${\gg}$ soybean. These orders did not consistently explain the selective phytotoxicity of alachlor. Analyses of extracts by reverse phase chromatography showed that alachlor was detoxified by conjugation with glutathione in all three plants and the rate of glutathione conjugation of soybean, the resistant species to alachlor, was the greatest, while that of barnyard grass, the susceptible, was the lowest among three plants. This result explained well the selective phytotoxicity of alachlor. Both absorption and translocation contribute undoubtedly to the selectivity by influencing the active internal concentration of alachlor. However, neither of them appeared to be a primary factor. It was concluded that the most important primary factor was the rate of glutathione conjugation, which detoxifies alachlor and plays an important role in selectivity.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.2
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• pp.229-237
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• 2008

Hazardous air pollutants emitted from the oil refinery plant were surveyed from 1993 US and 2005 Korean TRI data. Toluene, xylene, methanol, MTBE and n-hexane, relatively large in amount of fugitive emission, are considered as candidates of newly designated HAPs in Korea. The sealed oil pump, one of equipments among fugitive sources in the crude oil distillation tower was examined for the estimation of amounts of annual HAPs emissions according to several calculation methods using registered emission factors. Emission rates showed to be decreased with following calculation factors; average emission factor>pegged emission factor>concentration emission factor>correlation equation. Annual emission amounts of benzene, toluene, xylene. ethyl benzene and nhexane from the distillation tower were estimated and amounts of these HAPs calculated with TVOC concentrations obtained from LDAR program and correlation equations showed only 6% of those from using concentration factors.

• Journal of Applied Biological Chemistry
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• v.65 no.2
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• pp.93-99
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• 2022

Lysosome organelle extract (LOE) was derived from egg whites. The lysosome is an intracellular organelle that contains several hydrolysis enzymes. Previous studies have reported that LOE performs important functions, such as melanin de-colorization and anti-melanin production in B16F10 melanoma cells. However, its principal molecular and cellular mechanisms have not been elucidated till date. In non-cytotoxic conditions, LOE significantly inhibited α-MSH induced melanin synthesis of murine B16F10 cells. The anti-melanogenic activity of LOE was mediated by suppressing the mRNA expression of tyrosinase enzyme, tyrosinase related protein-1/2 (TRP-1/2), and microphthalmia-associated transcription factor (MITF) genes. By performing western blot analysis, we found that LOE significantly attenuated melanogenesis. In this case, LOE helped in increasing extracellular receptor kinase (ERK) phosphorylation in α-MSH induced B16F10 cells. Furthermore, MITF is found to be a key regulatory transcription factor in melanin synthesis; it was down-regulated by LOE through ERK phosphorylation. In this experiment, PD98059 (MEK inhibitor) was used to check whether LOE directly regulated the activity of ERK. Although LOE exerted inhibitory effect on melanin synthesis, we could not observe this effect in PD98059-treated α-MSH induced B16F10. These results strongly indicate that LOE is related to ERK activation and MITF degradation in anti-skin pigmentation. Hence, LOE should be utilized as a whitening agent of skin in the near future.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2001.11b
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• pp.96-96
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• 2001