• Animal cells and systems
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• 제2권1호
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• pp.117-122
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• 1998

D-raf, a Drosophila homolog of the human c-raf-1, is known as a signal transducer in cell proliferation and differentiation. A previous study found that the D-raf gene expression is regulated by the DNA replication-related element (DRE)/DRE-binding factor (DREF) system. In this study, we found the sequences homologous to transcription factor C/EBP, MyoD, STAT and Myc recognition sites in the D-raf promoter. We have generated various base substitutional mutations in these recognition sites and subsequently examined their effects on D-raf promoter activity through transient CAT assays in Kc cells with reporter plasmids p5'-878DrafCAT carrying the mutations in these binding sites. Through gel mobility shift assay using nuclear extracts of Kc cells, we detected factors binding to these recognition sites. Our results show that transcription factor C/EBP, STAT and Myc binding sites in D-raf promoter region play a positive role in transcriptional regulation of the D-raf gene and the Myo D binding site plays a negative role.

• Journal of Microbiology
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• 제35권4호
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• pp.323-326
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• 1997

Toxin protein from Ustilago maydis virus SH14 isolated in Korea was purified using ethanol precipitation, cation exchange, gel filtration and anion exchange chromatography. The molecular weight of the purified protein was estimated to be 8.3 kDa by SDS-PAGE analysis. The Nterminal sequence of the protein is L-G-I-N-C(K)-R-G-S-S-Q--C(K)-G-L-S-G which is highly homologous with that of P4 toxin, but the amino acid composition and electrophoretic mobility in a native PAGE of the toxin protein were totally different from those of P4 toxin respectively. The SH14 toxin was shown to have immunological cross-reactivity about 50% with P4 toxin when examined by Western hybridization.

• Biotechnology and Bioprocess Engineering:BBE
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• 제8권2호
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• pp.117-125
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• 2003

Experimental and theoretical works were performed for the separation of large polyelectrolyte, such as DNA, in a column packed with gel particles under the influence of an electric field. Since DNA quickly orient in the field direction through the pores, this paper presents how intraparticle convection affects the residence time distribution of DNAs in the column. The concept is further illustrated with examples from solid -liquid systems, for example, from chromatography Showing how the column efficiency is improved by the use of a n electric field. Dimensionless transient mass balance equations were derived, taking into consideration both diffusion and electrophoretic convection. The separation criteria are theoretically studied using two different Peclet numbers in the fluid and solid phases. These criteria were experimentally verified using two different DNAs via electrophoretic mobility measurements. which showed how the separation position of the DNAs varies in the column in relation to the Peg/Pef values of an individual DNA. The residence time distribution was solved by an operator theory and the characteristic method to yield the column response.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.14-14
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• 2003

Potato virus X (PVX), the type member of Potexvirus genus, is a flexuous rod-shaped virus containing a single-stranded (＋) RNA. Infection by PVX produces genomic plus- and minus-strand RNAs and two major subgenomic RNAs (sgRNAs). To understand the mechanism for PVX replication, we are studying the cis- and/or trans-acting elements required for RNA replication. Previous studies have shown that the conserved sequences located upstream of two major sgRNAs, as well as elements in the 5' non-translated region (NTR) affect accumulation of genomic and sg RNAs. Complementarity between sequences at the 5' NTR and those located upstream of two major sgRNAs and the binding of host protein(s) to the 5' NTR have shown to be important for PVX RNA replication. The 5 NTR of PVX contains single-stranded AC-rich sequence and stem-loop structure. The potential role(s) of these cis-elements on virus replication, assembly, and their interaction with viral and host protein(s) during virus infection will be discussed based on the data obtained by in vitro binding, in vitro assembly, gel shift mobility assay, host gene expression profiling using various mutants at these regions.

• 미생물학회지
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• 제29권5호
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• pp.270-277
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• 1991

A mutational alteration in the signal sequence of ribose-binding protein (RBP) of Escherichia coli, rbsB103, completely blocks the export of the protein to the periplasm. Intragenic suppressors for this mutation have been selected on minimal medium with ribose as a sole carbon source. Six suppressor mutations were characterized in detail and were found to have single amino acid wubstitution in the mature portion of RBP, which resulted in the mobility shift of the proteins on SDS polyacrylamide gel. Amino acid changes of these suppressors were localized in several peptides which are packed to form the N terminal domain of typical bilobate conformation of RBP. The involvement of SecB, a molecular chaperone, was investigated in the suppression of signal sequence mutation. Translocation efficency was found to be increased by the presence of SecB for all suppressors. It is likely that the folding characteristics of RBP altered by the suppressor mutations affect the affinity of interaction between SecB and RBP.

• BMB Reports
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• 제38권6호
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• pp.690-694
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• 2005

Transcription termination of the human mitochondrial genome requires specific binding to termination factor mTERF. In this study, mTERF was produced in E. coli and purified by two-step chromatography. mTERF-binding DNA sequences were isolated from a pool of randomized sequences by the repeated selection of bound sequences by gel-mobility shift assay and polymerase chain reaction. Sequencing and comparison of the 23 isolated clones revealed a 16-bp consensus sequence of 5'-GTG$\b{TGGC}$AGANCCNGG-3' in the light-strand (underlined residues were absolutely conserved), which nicely matched the genomic 13-bp terminator sequence 5'-$\b{TGGC}$AGAGCCCGG-3'. Moreover, mTERF binding assays of heteroduplex and single-stranded DNAs showed mTERF recognized the light strand in preference to the heavy strand. The preferential binding of mTERF with the light-strand may explain its distinct orientation-dependent termination activity.

• 생약학회지
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• 제27권3호
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• pp.267-273
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• 1996

The methanol extract of Taraxacum coreanum Nakai (Compositae) was examined on the in vitro oxidation of human low density lipoprotein (LDL). It is well known that LDL oxidation induced artherosclerosis, if we can protect LDL oxidation process, excess plasma lipoprotein accumulation into the arterial lesion prone areas can be blocked. The methanol extract was treated with oxidized LDL which was incubated with $16\;{\mu}M$ $Cu^{2+}$ for metal catalyzed oxidation and TBA value, mobility on agarose gel and formation of conjugated diene and change of vitamin E were determined for the evaluation. The extract showed antioxidative effect at concentration $200\;{\mu}g/ml$ on LDL oxidation.

• The Plant Pathology Journal
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• 제20권2호
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• pp.155-157
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• 2004

We isolated Rice dwarf virus (RDV) from infected plants in rice fields (Korea, Japan, China, the Philippines and Nepal) and analyzed their genomic dsRNAs by polyacrylamide gel eletrophoresis. The genomic dsRNAs of the isolates showed distinct electrophoretic mobility profiles. The S12 coding to nonstructural protein of Korean isolate (RDV-Kr) was further analyzed by sequencing. The S12 of RDV-Kr was 1,066bp long and coded for a protein composed of 312 amino acids including three open reading frames of P12, P120Pa and P120Pb. The sequence identities were 96% and 98.6% with Japanese isolates (H, AN), 94.7% with Nepalese isolate (NEL), 94% with Chinese isolate (CK) and the Philippines isolate (P).

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권5호
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• pp.366-371
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• 2000

The aim of this study was to investigate the efficiency of the pentagalloic acid compound in inhibiting the metal ions and cell lines that mediate in low density lipoprotein (LDL) oxidation. Pentagalloic acid prolonged the lag time preceeding the onset of conjugated diene formation. In chemically induced LDL oxidation by Cu$^2$(sup)+ plus hydrogen peroxide or peroxyl radical generated by 2, 2-azo-vis (2-amidino propane) hydrochloride (AAPH), pentagalloic acid inhibited LDL oxidation as monitored by measuring the thiobarbituric acid reactive substances(TBARS), malondialdehyde(MDA), and gel electrophoretic mobility. The physiological relevance of the antioxidative activity was validated at the cellular level where pentagalloic acid inhibited mouse macrophage J774 and endothelial cell-mediated LDL oxidation. When compared with several other antioxidants, pentagalloic acid showed a much higher ability than naturally occuring antioxidants, ${\alpha}$-tocopherol and ascorbic acid, and the synthetic antioxidant, probucol.

• 한국동물학회지
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• 제30권3호
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• pp.211-221
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• 1987

Starch gel electrophoresis was used to estimate the degree of genic variation and genetic relatedness among twelve populations of the Cat-Sanke(Elaphe diene) in Korea. Out of the 17 loci examined 9 loci (Mdh-2, Ldh-1, Ldh-2, Idh-1, Idh-2, Adh, Aco-3, ep, Got-1) were monomorphic with identical mobility in all populations, 4 loci (Pgm, Mpi, Pept-1, Got-2) were nearly identical with minor allele frequency differences, and 4 loci (Mdh-1, Fgi, Est-2, 6psd) showed moderate variation. Levels of genic variation were similar to those found for other reptilian species. The mean genetic similarity value(S) among twelve populations is 0.966. Chechu population was slightly remote genetically from the mainland populations.