• The Journal of the Korean Society for Microbiology
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• v.22 no.2
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• pp.167-174
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• 1987

N-myc, a DNA sequence related to the oncogene c-myc, was found to be amplified in untreated primary neuroblastomas and the amplification appeared to be associated with advanced disease at diagnosis and rapid tumor progression. Synthetic peptides have been useful immunogens for generating antisera and monoclonal antibodies to a number of native proteins. In order to identify myc-related protein in the tumor cells, an antiserum against a synthetic hexapeptide (-Glu-Asp-Ile-Trp-Lys-Lys-), whose sequence corresponds to a part of the exon 2 of oncogene N-myc, was prepared by immunizing a rabbit with BSA-conjugated peptide. After ammonium sulfate precipitation and affinity column chromatography, it appeared to be specific to the peptide. Strong nuclear staining in immunoperoxidase method using this serum was observed in both human promyeloid leukemic cell line, HL-60(containing high c-myc copy number), and human neuroblastoma cell line, LA-N-5 (containing high N-myc copy number), whereas LA351 (human lymphoid cell line) cells did not react with the serum. This reaction was completely abrogated by incubating the antiserum with soluble excess peptide. These data suggest that the protein encoded by N-myc could be localized in the nucleus as c-myc protein and this antiserum can be used to detect myc-related tumor cells in clinical samples and to determine if the N-myc expression correlates with genomic amplification in cell lines, untreated primary tumors, and untreated metastases.

• Molecular & Cellular Toxicology
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• v.3 no.1
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• pp.11-18
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• 2007

Mechanisms of insecticide resistance found in insects may include three general categories. Modified behavioral mechanisms can let the insects avoid the exposure to toxic compounds. The second category is physiological mechanisms such as altered penetration, rapid excretion, lower rate transportation, or increased storage of insecticides by insects. The third category relies on biochemical mechanisms including the insensitivity of target sites to insecticides and enhanced detoxification rate by several detoxifying mechanisms. Insecticides metabolism usually results in the formation of more water-soluble and therefore more readily eliminated, and generally less toxic products to the host insects rather than the parent compounds. The representative detoxifying enzymes are general esterases and monooxygenases that catalyze the toxic compounds to be more water-soluble forms and then secondary metabolism is followed by conjugation reactions including those catalyzed by glutathione S-transferases (GSTs). However, a change in the resistant species is not easily determined and the levels of mRNAs do not necessarily predict the levels of the corresponding proteins in a cell. As genomics understands the expression of most of the genes in an organism after being stressed by toxic compounds, proteomics can determine the global protein changes in a cell. In this present review, it is suggested that the environmental proteomic application may be a good approach to understand the biochemical mechanisms of insecticide resistance in insects and to predict metabolomic changes leading to physiological changes of the resistant species.

• Toxicological Research
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• v.30 no.1
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• pp.33-38
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• 2014

The human cytochrome P450 2J2 catalyzes an epoxygenase reaction to oxidize various fatty acids including arachidonic acid. In this study, three recombinant enzyme constructs of P450 2J2 were heterologously expressed in Escherichia coli and their P450 proteins were successfully purified using a $Ni^{2+}$-NTA affinity column. Deletion of 34 amino acid residues in N-terminus of P450 2J2 enzyme (2J2-D) produced the soluble enzyme located in the cytosolic fraction. The enzymatic analysis of this truncated protein indicated the typical spectral characteristics and functional properties of P450 2J2 enzyme. P450 2J2-D enzymes from soluble fraction catalyzed the oxidation reaction of terfenadine to the hydroxylated product. However, P450 2J2-D enzymes from membrane fraction did not support the P450 oxidation reaction although it displayed the characteristic CO-binding spectrum of P450. Our finding of these features in the N-terminal modified P450 2J2 enzyme could help understand the biological functions and the metabolic roles of P450 2J2 enzyme and make the crystallographic analysis of the P450 2J2 structure feasible for future studies.

• Parasites, Hosts and Diseases
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• v.45 no.4
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• pp.287-293
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• 2007

The identification and characterization of antigens that elicit human T cell responses is an important step toward understanding of Leishmania major infection and ultimately in the development of a vaccine. Micropreparative SDS-PAGE followed by electro transfer to a PVDF membrane and elution of proteins from the PVDF, was used to separate 2 novel proteins from L. major promastigotes, which can induce antibodies of the IgG2a isotype in mice and also are recognized by antisera of recovered human cutaneous leishmaniasis subjects. Fractionation of the crude extract of L. major revealed that all detectable proteins of interest were present within the soluble Leishmania antigens (SLA). Quantitation of these proteins showed that their expression in promastigotes is relatively very low. Considering the molecular weight, immunoreactivity, chromatographic and electrophoretic behavior in reducing and non-reducing conditions, these proteins are probably 2 isoforms of a single protein. A digest of these proteins was resolved on Tricine-SDS-PAGE and immunoreactive fragments were identified by human sera. Two immunoreactive fragments (36.4 and 34.8 kDa) were only generated by endoproteinase Glu-C treatment. These immunoreactive fragments or their parent molecules may be ideal candidates for incorporation in a cocktail vaccine against cutaneous leishmaniasis.

• Microbiology and Biotechnology Letters
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• v.36 no.4
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• pp.260-267
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• 2008

The choice of expression vector is very important for industrial production of proteins. Therefore, the systematic mining of promoters over a wider range of genetic resource and/or host is required. We previously reported a novel bidirectional reporting system (pBGR) for the isolation of promoters from metagenome and screened useful promoters that functioned constitutively in E. coli under general culture conditions. Among them, three promoter sequences including each upstream region were amplified by PCR and used to construct new expression vectors. To facilitate subcloning, a multi-cloning site was incorporated into the downstream region of the revere primer sequence. At these sites, GFP, esterase and $\beta$-glucosidase were subcloned and analyzed the constitutive expression ability of new promoter in terms of protein solubility and expression level. As a result, these vectors expressed the proteins constitutively to a level of $2{\sim}3%$ of the total cell protein in soluble fraction (>80 %). This study suggested that excavation of metagenomic promoters for construction of expression vector in a certain strain could provide a way for the development of the expression systems.

• Korean Journal of Acupuncture
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• v.29 no.2
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• pp.260-270
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• 2012

Objectives : Hippocampus, a region of temporal lobe, plays an important role in the pathogenic mechanisms of brain diseases such as Alzheimer's disease, depression and temporal lobe epilepsy. This research is designed to investigate hippocampal changes after acupuncture stimulation at Shinmun(HT7) using 2-dimensional gel electrophoresis(2-DE). Methods : On postnatal-day 15, rat pups were randomly devided into Normal(NOR) or HT7 group. All of Pups kept with their mothers for 7 days, but pups in HT7 group received acupuncture stimulation at HT7 daily. On postnatal-day 21, hippocampus of each rat pup was dissceted 30 minutes after last acupuncture stimulation and the protein expressions were investigated using 2-DE. Results : After acupuncture stimulation at HT7, expression of 20 proteins were significantly increased. Succinate semialdehyde dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase-like, transketolase, aconitate hydratase and phosphoglucomutase-1 were related to glucose methabolism. Eukaryotic initiation factor(eIF) 4A-II, eIF 4A-III, mitochondrial Tu translation elongation factor and chain A of crystal structure of the 70-Kda heat shock cognate protein involve in the protein synthesis in ribosome. Tubulin ${\beta}$-4 chain, tubulin T ${\beta}$-15 and tubulin ${\alpha}$-1B chain comprise cytoskeleton. Glutathione S-transferase(GST) ${\omega}$-1, GST P and GST Yb-3 can reduce oxidative stress. ${\beta}$-soluble N-ethylmaleimide-sensitive fusion protein attachment protein is required for vesicular transport between the endoplasmic reticulum and the Golgi apparatus, glycerol-3-phosphate dehydrogenase plays a major role in lipid biosynthesis, creatine kinase U-type catalyses the conversion of creatine and consumes adenosine triphosphate to create phosphocreatine and adenosine diphosphate. Platelet-activating factor acetylhydrolase IB subunit alpha and voltage depedent anion-selective channel protein 2 were also increased. Conclusions : The results suggest that acupuncture stimulation at HT7 may enhance glucose and lipid metabolism, protein synthesis, cytoskeletal substance and anti-oxidative stress in hippocampus.

• Parasites, Hosts and Diseases
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• v.54 no.4
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• pp.385-391
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• 2016

The discovery and understanding of antigenic proteins are essential for development of a vaccine against malaria. In Plasmodium falciparum, Pf92 have been characterized as a merozoite surface protein, and this protein is expressed at the late schizont stage, but no study of Pv92, the orthologue of Pf92 in P. vivax, has been reported. Thus, the protein structure of Pv92 was analyzed, and the gene sequence was aligned with that of other Plasmodium spp. using bioinformatics tools. The recombinant Pv92 protein was expressed and purified using bacterial expression system and used for immunization of mice to gain the polyclonal antibody and for evaluation of antigenicity by protein array. Also, the antibody against Pv92 was used for subcellular analysis by immunofluorescence assay. The Pv92 protein has a signal peptide and a sexual stage s48/45 domain, and the cysteine residues at the N-terminal of Pv92 were completely conserved. The N-terminal of Pv92 was successfully expressed as soluble form using a bacterial expression system. The antibody raised against Pv92 recognized the parasites and completely merged with PvMSP1-19, indicating that Pv92 was localized on the merozoite surface. Evaluation of the human humoral immune response to Pv92 indicated moderate antigenicity, with 65% sensitivity and 95% specificity by protein array. Taken together, the merozoite surface localization and antigenicity of Pv92 implicate that it might be involved in attachment and invasion of a merozoite to a new host cell or immune evasion during invasion process.

• BMB Reports
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• v.33 no.4
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• pp.337-343
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• 2000

The human immunodeficiency virus type 1 (HIV-1), transactivator of transcription (Tat), is one of the viral gene products that is essential for HIV-1 replication. The HIV-l Tat protein regulates transcription from an HIV-1 long terminal repeat (LTR) and affects the gene expression of cellular proteins during infection. In order to develop an expression system to overexpress and simply purify HIV-1 Tat proteins, the HIV-1 Tat coding sequences that contain one or two exons were amplified using PCR and cloned into a pET vector, which contains a consecutive stretch of six histidine residues at the amino-terminus. The reconstituted vectors were overexpressed in the E. coli strain and the soluble recombinant proteins were purified to be homogeneity in a single step by $Ni^{+2}-nitrilotriacetic$ acid Sepharose chromatography under nondenaturing conditions. Recombinant HIV-1 Tat proteins were shown to transactivate the HIV-1 LTR promoter in a dose-dependent manner when introduced into mammalian cells. In addition, treatment of human endothelial cells with purified Tat proteins resulted in a significant increase in the level of vascular cell adhesion molecule-1 (VCAM-1) expression. These results indicate that the recombinant HIV-1 Tat proteins are active in transactivating viral and cellular promoters. The expression and purification system described in this study will facilitate in characterizing the biological functions of the Tat proteins.

• Biomolecules & Therapeutics
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• v.19 no.1
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• pp.70-76
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• 2011

Bone remodeling is a dynamic process involving a constant balance between osteoclast-induced bone resorption and osteoblast-induced bone formation. Osteoclasts play a crucial homeostatic role in skeletal modeling and remodeling, and destroy bone in many pathological conditions. Previously, we reported that the hexane soluble fraction of Ficus carica inhibited osteoclast differentiation. Poly unsaturated fatty acids, such as ethyl docosahexaenoate (E-DHA), docosahexaenoic acid (DHA), cis-11,14-eicosadienoic acid (EDA) and eicosapentaenoic acid (EPA), were identified from the hexane soluble fraction of Ficus carica. Among them, E-DHA most potently inhibited osteoclastogenesis in RAW264.7 cells. E-DHA reduced the activities of JNK and NF-$\kappa}B$. E-DHA suppressed the expression of c-Fos and nuclear factor of activated T cells c1 (NFATc1). Interestingly, DHA increased the activity of alkaline phosphatase and expression of bone morphogenetic protein 2 (BMP2) more than E-DHA in MC3T3-E1 cells, suggesting that DHA may induce osteoblast differentiation. The data suggests that a combination of E-DHA and DHA has potential use in the treatment of diseases involving abnormal bone lysis, such as osteoporosis, rheumatoid arthritis and periodontal bone erosion.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.3
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• pp.141-146
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• 2004

Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) proteins, composed of two presynaptic membrane proteins [synaptosomal-associated protein of 25 kDa (SNAP-25) and syntaxin] and a presynaptic vesicular protein [vesicle-associated membrane protein (VAMP)], serve as a core of exocytotic fusion machinery, which can be affected by ischemia. Synaptic protein in core region, striatum and cortex has been shown to alter after focal ischemia, however, little is known in hippocampus. Hippocampus is remote from ischemic core, but it is one of the most vulnerable regions. Using immunohistochemistry, the present study was undertaken to investigate the alteration of expression of SNAP-25, syntaxin, and VAMP in the hippocampus of rats which were subjected to middle cerebral artery occlusion (MCAO) for 2h and allowed to reperfuse. At 2 weeks of reperfusion, the SNAP-25 and syntaxin immunoreactivity was increased in the stratum oriens of the CA1 and the stratum lucidum of the CA3 in the ipsilateral hippocampus. However, VAMP immunoreactivity didn't show significant change. These results demonstrate that the level of the presynatpic plasma membrane proteins (SNAP-25 and syntaxin) in the rat hippocampus is more sensitively affected by focal ischemia than that of the synaptic vesicle protein (VAMP).