• Journal of Microbiology and Biotechnology
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• v.17 no.11
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• pp.1841-1847
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• 2007

We previously identified the origin of replication of p703/5, a small cryptic plasmid from the KBL703 strain of Enterococcus faecalis. The origin of replication contains putative regulatory cis-elements required for replication and a replication initiator (RepA) gene. The replicon of p703/5 is similar in its structural organization to theta-type plasmids, and RepA is homologous to a family of Rep proteins identified in several plasmids from Gram-positive bacteria. Here, we report molecular interactions between RepA and the replication origin of p703/5. DNase I footprinting using recombinant RepA together with electrophoretic mobility shift assays confirmed the binding of RepA to the replication origin of p703/5 via iterons and an inverted repeat. We also demonstrated the formation of RepA dimers and the different binding of RepA to the iteron and the inverted repeat using gel filtration chromatographic analysis, a chemical crosslinking assay, and electrophoretic mobility shift assays in the presence of guanidine hydrochloride. Our results suggest that RepA plays a regulatory role in the replication of the enterococcal plasmid p703/5 via mechanisms similar to those of typical iteroncarrying theta-type plasmids.

• BMB Reports
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• v.43 no.11
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• pp.744-749
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• 2010

The aim of this work was to determine whether intrinsically bent DNA sites are present at, or close to, the mammalian replication origins oriGNAI3 and oriB in the Chinese hamster AMPD2 locus. Using an electrophoretic mobility shift assay and in silico analysis, we located four intrinsically bent DNA sites (b1 to b4) in a fragment that contains the oriGNAI3 and one site (b5) proximal to oriB. The helical parameters show that each bent DNA site is curved in a left-handed superhelical writhe. A 2D projection of 3D fragment trajectories revealed that oriGNAI3 is located in a relatively straight segment flanked by bent sites b1 and b2, which map in previously identified Scaffold/Matrix Attachment Region. Sites b3 and b4 are located approximately 2 kb downstream and force the fragment into a strong closed loop structure. The b5 site is also located in an S/MAR that is found just downstream of oriB.

• Journal of Life Science
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• v.22 no.12
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• pp.1712-1717
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• 2012

Oxidation of low density lipoprotein (LDL) plays an important role in the development and progression of atherosclerotic disease. In this study, human LDL was isolated and oxidized using $CuSO_4$ in the presence or absence of S-allylmercaptocysteine. Oxidative modification of the LDL fraction was monitored by both the appearance of thiobarbituric acid substances (TBARS), an increase in electrophoretic mobility, and conjugated diene formation. The addition of S-allylmercaptocysteine reduced lipid peroxide formation, indicating it to be an effective antioxidant. The inhibition of LDL oxidation by $5{\sim}20{\mu}g/ml$ S-allylmercaptocysteine occurred in a dose-dependent manner, as assessed by the TBARS assay. S-allylmercaptocysteine at $20{\mu}g/ml$ almost completely inhibited the $Cu^{2+}$ induced increases in electrophoretic mobility of LDL and almost completely inhibited conjugated diene formation. A more potent antioxidative activity was observed for S-allylmercaptocysteine than for either Vitamin C or $d{\ell}-{\alpha}$-tocopherol. Thus, S-allylmercaptocysteine aid in preventing the development and progression of atherosclerotic disease.

• Preventive Nutrition and Food Science
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• v.3 no.2
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• pp.143-151
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• 1998

Protein -surfactant interactions have been investigate by measuring ζ-potential of $\beta$-lactoglobulin-coated emulsion droplets and $\beta$-lactoglobulin in solution in the rpesenceof surfactant, with particular emphasis on the effect of protein heat treatment(7$0^{\circ}C$, 30min). When ionic surfactant (SDS or DATEM) is added to the protein solution, the ζ-potential of the mixture is found to increase with increasing surfactant concentration, indicating surfactant binding to the protein molecules. For heat-denatured protein,it has been observed that the ζ-potential tends to be lower than that of the native protein. The effect of surfactant on emulsions is rather complicated .With SDS, small amounts of surfactant addition induce a sharp increase in zeta potential arising from the specific interaction of surfactant with protein. With further surfacant addition, there is a gradual reductio in the ζ-potential, presumably caused by the displacement of adsorped protein (and protein-surfactant complex) from the emulsion droplet surfac by the excess of SDS molecules. At even higher surfactant concentrations, the measured zeta potential appears to increase slightly, possibly due to the formation of a surfactant measured zeta potential appears to increase slightly, possibly due to the formation of surfactant micellar structure at the oil droplet surface. This behaviour contrastswith the results of the corresponding systems containing the anionic emulsifier DATEM, in which the ζ-potential of the system is found to increase continuously with R, particularly at very low surfactant concentration. Overall, such behaviour is consisten with a combination of complexation and competitive displacement between surfactant and protein occurring at the oil-water interface. In addition, it has also been found that above the CMC, there is a time-dependent increase in the negative ζ-potential of emulsion droplets in solutions of SDS, possibly due to the solublization of oil droplets into surfactant micelles in the aqueous bulk phase.

• Analytical Science and Technology
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• v.34 no.4
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• pp.143-152
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• 2021

Capillary electrophoresis (CE) is an effective technique to study chiral recognition because it offers flexibility in adjusting vital factors. Currently, various available cyclodextrins (CDs) can be employed for the chiral separation of numerous analytes. Herein, we investigate the enantioseparation behavior of lipoic acid enantiomers in various types of single and dual CD systems through CE. Additionally, several impacted CE parameters were optimized through the systematic investigation based on the design of experiment (DoE) concept for a single system comprising a heptakis (2,3,6-tri-O-methyl)-β-CD and a dual system containing the combination of the single CD with a sulfated-β-CD. Consequently, absolute enantioresolution was obtained within 15 min on a common standard bare fused-silica capillary (64.5/56 cm in total/effective length, 50/365 ㎛ inner/outer diameter), maintained at 15 ℃ and at an applied voltage of 24 kV. The optimal background electrolyte consisted of 6 mM heptakis (2,3,6-tri-O-methyl)-β-CD dissolved in the solution of 58 mM borate buffer at pH 10. Furthermore, the results of apparent binding constant experiments indicated that the S-enantiomer-heptakis (2,3,6-tri-O-methyl)-β-CD complex exhibited a stronger affinity than its R-enantiomer counterpart. The obtained electrophoretic mobility values could be utilized to interpret the resolution achieved at various CD concentrations and the mobility behavior of the complexes elucidated the migration order of the enantiomers in an electropherogram.

• Applied Chemistry for Engineering
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• v.34 no.1
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• pp.45-50
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• 2023

Microfluidic preconcentration technologies, which collect or extract low-abundance analytes in a specific location, have been spotlighted in various applications such as medical and bio-engineering. Here, we conducted extensive studies on the variables to be considered when concentrating target samples based on electrophoresis in an electromembrane system utilizing an ion exchange membrane. Using negatively charged Alexa Fluor 488 and positively charged Rhodamine 6G as fluorescent dyes, we examined the effects of flow velocity of the main channel, channel electrolyte concentration, and applied voltage on sample preconcentration. As a result, it was found that the preconcentration of the target sample occurs much better when the flow velocity is slow and the concentration of the main channel containing the sample is high, given that the channel concentration ratio (main and buffer) is constant. In addition, based on the experimental data acquired in this study, the electrophoretic mobility values of Alexa Fluor 488 and Rhodamine 6G were experimentally calculated and compared.

• Tuberculosis and Respiratory Diseases
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• v.46 no.2
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• pp.185-194
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• 1999

Background: NF-$\kappa$B is a characteristic transcriptional factor whose functional activity is determined by post-translational modification of protein and subsequent change of subcellular localization. The involvement of the NF-$\kappa$B family of the transcription factors in the control of such vital cellular functions as immune response, acute phase reaction, replication of certain viruses and development and differentiation of cells has been clearly documented in many previous studies. Several recent observations have suggested that the NF-$\kappa$B might also be involved in the carcinogenesis of some hematological and solid tumors. Investigating the possibility that members of the NF-$\kappa$B family participate in the molecular control of malignant cell transformation could provide invaluable information on both molecular pathogenesis and cancer-related gene therapy. Method: To determine the expression patterns and functional roles of NF-$\kappa$B family transcription factors in human lung cancer cell lines NCI-H792, NCI-H709, NCI-H226 and NCI-H157 were analysed by western blot, using their respective antibodies. The nuclear and the cytoplasmic fraction of protein extract of these cell lines were subsequently obtained and NF-$\kappa$B expression in each fraction was again determined by western blot analysis. The type of NF-$\kappa$B complex present in the cells was determined by immunoprecipitation. To detect the binding ability of cell-line nuclear extracts to the KB consensus oligonucleotide, electrophoretic mobility shift assay(EMSA) was performed. Results: In the cultured human lung cancer cell lines tested, transcription factors of the NF-$\kappa$B family, namely the p50 and p65 subunit were expressed and localized in the nuclear fraction of the cellular extract by western blot analysis and immunocytochemistry. Immunoprecipitation assay showed that in the cell, the p50 and p65 subunits made NF-$\kappa$B complex. Finally it was shown by Electrophoretic Mobility Shift Assay(EMSA) that nuclear extracts of lung cancer cell lines are able to bind to NF-$\kappa$B consensus DNA sequences. Conclusion: These data suggest that in human lung cancer cell lines the NF-$\kappa$B p50/p65 complex might be activated. and strengthen the hypothesis that NF-$\kappa$B family transcription factors might be involved in the carcinogenesis of human lung cancer.

• Journal of Life Science
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• v.15 no.2 s.69
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• pp.253-260
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• 2005

Mitotic centromere-associated kinesin (MCAK), which is a member of the Kin I (internal motor domain) subfamily of kinesin-related proteins, is known to play a role in mitotic segregation of chromosome during M phase of the cell cycle. In the present study, we have produced a rat polyclonal antibody using human MCAK (HsMCAK) expressed in E. coli as the antigen. The antibody specifically recognized the HsMCAK protein (81 kDa), and could detect its nuclear localization in human Jurkat T cells and 293T cells by Western blot analysis. The specific stage of the cell cycle was obtained through blocking by either hydroxyl urea or nocodazole and subsequent releasing from each blocking for 2, 4, and 7 h. While the protein level of HsMCAK reached a maximum level in the S phase with slight decline in the $G_{2}-M$ phase, the electrophoretic mobility shift from $p81^{MCAK}\;to\;p84^{MCAK}$ began to be induced in the late S phase and reached a maximum level in the $G_{2}/M $ phase, and then it disappeared as the cells enter into the $G_{1}$ phase. Immunocytochemical analysis revealed that HsMCAK protein localized to centrosome and nucleus at the interphase, whereas it appeared to localize to the spindle pole, centromere of the condensed mitotic DNA, spindle fiber, or midbody, depending on the specific stage of the M phase. These results demonstrate that a rat polyclonal antibody raised against recombinant HsMCAK expressed in E. coli specifically detects human MCAK, and indicate that the electrophoretic mobility shift from $p81^{MCAK}\;to\;p84^{MCAK}$, which may be associated with its differential intracellular localization during the cell cycle, fluctuates with a maximum level of the shift at the $G_{2}-M$ phase.

• YAKHAK HOEJI
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• v.22 no.2
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• pp.72-82
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• 1978

This study was undertaken establish the relationship between trypsin inhibitor in raw soybean and antinutritional effect of raw legumes. 1) Among legumes produced in Korea, Glycine max contains a relatively high amount of protein(higher than 40%) compared with kindey bean, sword bean and mung bean and, furthermore, soybean which contains a high amount of protein possesses high trypsin inhibitory activity. 2) Disc electrophoretic pattern exhibited pattern exhibited that the crude protein preparation from Glycine max produced about 9-12 protein bands, and the pattern of electrophoretic mobility was very similar to each other. However, only a few protein bands were observed from the crude protein preparation of yard long bean, sword bean, adzuki bean, mung bean and rice adzuki. From the eluate of the sliced gel, it was confirmed that among those bands, only the fastest moving band contains trypsin inhibitory activity. 3) In chicks fed the normal diet the body weight was increased steady from one week and reached to 40% increase for three weeks but in chick fed raw bean diet, there was no body weight gain until two weeks feeding and only 10-20% of body weight gain was observed at the end of three week feeding. On the other hand, in chicks fed raw bean diet the weight of pancreatic tissue per 100g body weight was increased to about two-fold for two or three weeks but there was no change in liver weight. 4) In the case of amylase secretion from the pancreatic fragment, very strong stimulation on amylase secretion from pancreatic tissue of chicks fed a normal diet was produced by one unit of cholecystokin-pancreozymin. However, no stimulation was observed from pancreatic fragment of chick fed raw bean diet.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.7
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• pp.1-8
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• 2008

We fabricated flexible electrophoretic display(EPD) driven by organic thin film transistors(OTFTs) on plastic substrate. We designed the W/L of OTFT to be 15, considering EPD's transient characteristics. The OTFTs employed bottom contact structure and used Al for gate electrode, the cross-linked polyvinylphenol for gate insulator, pentacene for active layer. The plastic substrate was coated by PVP barrier layer in order to remove the islands which were formed after pre-shrinkage process and caused the electrical short between bottom scan and top data metal lines. Pentacene active layer was confined within the gate electrodes so that the off current was controlled and reduced by gate electrodes. Especially, PVA/Acryl double layers were inserted between EPD panel and OTFT-backplane in order to protect OTFT-backplane from the damages created by lamination process of EPD panel on the backplane and also accommodate pixel electrodes through via holes. From the OTFT-backplane the mobility was $0.21cm^2/V.s$, Ion/Ioff current ratio $10^5$. The OTFT-EPD panel worked successfully and demonstrated to display some patterns.