• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1093-1098
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• 2001

The gene coding for a Lepidoptera-specific insecticidal crystalline (or control) protein (ICP), recognized as cryIAc, from Bacillus thuringiensis subsp. kurstaki HD-73, was cloned into the vector pBluscript ll SK-, and then transformed in Escherichia coli $DH5{\alpha}$. The clone was named EBtIAc and the chimeric phagemid, as pEBtIAc. Hyperexpression of CryIAc protoxin was observed in the extract of the culture of E. coli harboring pEBtIAc. Crystalline protoxin was purified by differential solubility. It was dissolved in alkaline pH, and exposed to trypsin to be activated. The molecular weights of the pro- and activated toxins on SDS-PAGE were estimated to be ca. 130 kDa and 60 kDa, respectively. The toxicity was tested by force-feeding larvae of gypsi moth (Lymantria diapar) with trypsinized protoxin. Using the batch of biologically active form of the toxin as an immunogen, anti-CryIAc antiserum was raised in a New Zealand white rabbit. Immunoglobulin G was fractionated from the seam by Protein-A sepharose affinity chromatography. Immunoreactivity of the antibody was examined by dot and Westerns blottings. It has been found that the anti- CryIAc antibody recognized the purified toxin at a level below a nanogram in terms of quantity. Using the antibody some of Bt-corns were able to be differentiated from tons of corn kernels which were imported from America as forage crops.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.10
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• pp.1498-1504
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• 2005

Competitive direct ELISA was developed to detect gentamicin residues. Mice immunized with gentamicin-keyhole limpet hemocyanin (KLH) conjugate developed good antiserum titers, which gradually increased with booster injections, indicating immunization was successfully processed. Monoclonal antibody against gentamicin was prepared using hybridoma cells cloned by limit dilution of fused cells. IgG was purified from ascites fluid of hybridoma cell-injected mice through ammonium sulfate precipitation and Sephadex G-25 gel filtration. After the gel filtration, fractions of high antibody titer were further purified through affinity chromatography on protein A/G column. Monoclonal antibody against gentamicin was confirmed as IgG1, which has kappa light chain. Cross-reactivities ($CR_{50}$) of gentamicin monoclonal antibody to other aminoglycosides (kanamycin, neomycin, and streptomycin) were less than 0.005%, indicating the monoclonal antibody was highly specific for gentamicin. Standard curve constructed through competitive direct ELISA showed measurement range (from 80 to 20% of B/$B_0$ ratio) of gentamicin was between 1 and 40 ng/ml, and 50% of B/$B_0$ ratio was about 4 ng/ml. The gentamicin concentration rapidly increased to 1,300 ng/ml after the intramuscular administration up to 2 h, then sharply decreased to less than 300 ng/ml after 4 h of withdrawal, during which the elimination half-life ($t_{1/2}$) of gentamicin in the rabbit plasma was estimated to be 1.8 h. Competitive direct ELISA method developed in this study using the prepared monoclonal antibody is highly sensitive for gentamicin, and could be useful for detecting gentamicin residues in plasma of live animals.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.112-112
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• 2003

Voltage-gated $K^{+}$ (Kv) channels represent a structurally and functionally diverse group of membrane proteins. These channels play an important role in determining the length of the cardiac action potential and are the targets for antiarrhythmic drugs. Many $K^{+}$ channel genes have been cloned from human myocardium and functionally contribute to its electrical activity. One of these channels, Kv1.5, is one of the more cardiovascular-specific $K^{+}$ channel isoforms identified to date and forms the molecular basis for an ultra-rapid delayed rectifier $K^{＋}$ current found in human atrium. Thus, the blocker of hKv1.5 is expected to be an ideal antiarrhythmic drug for atrial fibrillation. Chelidonine was isolated from Chelidonium majus L. We examined the effect of chelidonine on the hKv1.5 current expressed in Ltk-cells using whole cell mode of patch clamp techniques. Chelidonine selectively inhibited the hKv1.5 current expressed in Ltk-cells in a concentration-dependent manner, whereas did not affect the HERG current expressed in HEK-293 cells. Additionally, chelidonine reduced the tail current amplitude recorded at -50 mV after 250 ms depolarizing pulses to +60 mV, and slowed the deactivation time course resulting in a 'crossover' phenomenon when the tail currents recorded under control conditions and in the presence of chelidonine were superimposed. We found that chelidonine also inhibited the $K^{+}$ current in isolated human atrial myocytes where hKv1.5 channels were predominantly expressed. Furthermore, we examined the effects of chelidonine on the action potentials in rabbit hearts using conventional microelectrode technique. Chelidonine prolonged the action potential durations (APD) of atrial, ventricular myocytes and Purkinje fibers in a dose-dependent manner. However, the effect of chelidonine on atrial APD was frequency-dependent whereas the effect of chelidonine on the APDs of ventricular myocytes and Purkinje fibers was not frequency- dependent. Also, the selective action of chelidonine on heart was more potent than dofetilide, $K^{+}$ channel blocker.

• The Plant Pathology Journal
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• v.16 no.2
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• pp.110-117
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• 2000

Potato virus X (PVX-KO) showing mild mosaic and stunting symptoms on potato (Solanum tuberosum) in Kangwon area has been isolated and characterized. EM observation of the purified virus particles showed flexuous rod shape of about 520 nm in length. The coat protein (CP) of the virus had a molecular weight of 31 kDa in SDS-PAGE analysis, and the viral RNA was approximately 6.4 kb in size in denatured agarose gel electro-phoresis. In gel-immunodiffusion tests, it reacted strongly with an antiserum to common PVX from BIOREABAAG (USA). A rabbit antiserum was produced using purified virus and used for routine PVX detection by ELISA. Cultivated potatoes in Kangwon and other areas were frequently infected with PVX-KO. Both Datura stramonium and Nicotiana tabaccum cultivars developed necrotic local lesions 5 days after inoculation, and systemic mosaic symptoms with vein clearing 2 weeks after inoculation. All the features agree with the description of other PVX strains. To confirm and determine PVX strains, reverse transcription-polymerase chain reaction experiment was conducted using specific primers for viral CP. Amplified DNA fragments were cloned and sequenced. Results showed nucleotide sequence homologies of about 88 to 99% to other PVX strains. Based on CP amino acid sequence deduced from nucleotide sequences and host range studies PVX-KO is considered a member of the type X subgroup of PVX.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.116-120
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• 2004

The medicinal properties of Ganoderma lucidum have been recognized in China for many centuries. Active pharmaceutical components include triterpenes. To elucidate the molecular regulation of triterpene biosynthesis in this mushroom, a 57-base pair DNA fragment encoding the fourth conserved domain SQ-4 (SMGLFLQKTNIIRDYNEDL) of squalene synthase was synthesized and cloned into the expression vector pET-32a(＋). The recombinant fusion protein induced by IPTG (isopropyl-$\beta$-D-thiogalactopyranoside) was overexpressed in the Escherichia coli. Using the purified recombinant fusion protein of 20.9 kDa, a specific polyclonal antibody was obtained from immunized rabbit. Expression of squalene synthase at different development stages of Ganoderma lucidum was analyzed.

• Development and Reproduction
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• v.11 no.3
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• pp.253-261
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• 2007

Lactadherin is a glycoprotein of human milk fat globule membrane that binds to mucin and butyrophilin forming the protein complex. Especially, mucin and lactadherin in human milk efficiently protect infants with poor immune functions right after birth from infections by microorganisms and play important roles for their early survival, growth and development. Lactadherin inhibits the propagation and growth of rotavirus that is a global pathogen causing infants' diarrhea. Recently this protein was known to promote neovascularization and its deficiency related to develop Alzheimer's disease. In this study, the basic biochemical and physiological aspects of lactadherin were investigated. Messenger RNAs were isolated from mammary tissues from Korean women patients to clone a 1.2 kb cDNA and sequenced its DNA to determine its amino acid sequences. The cDNA was cloned to express its 43 kD protein in E. coli, which was confirmed by Western blot. The recombinant protein was purified and injected to 2 rabbits to raise antibodies against it. The semi-purified milk fat globule membrane proteins from Korean women was analyzed by Western blot using the rabbit antibody to give 70, 55, 46, 30 kD bands. Also several polymorphism and SNPs of lactadherin gene from Korean women were observed compared with those of Caucasian women.

• Journal of fish pathology
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• v.22 no.2
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• pp.137-146
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• 2009

The black rockfish Sebastes schlegelii neutrophil cytosolic factor components p47 phox (phagocyte oxidase) cDNA was cloned. The sequence of the cDNA showed that rockfish p47 phox cDNA consisted of 1,952 bp contained open reading frame encoding predicted polypeptide of 420 amino acids. Additionally analysis of the p47 phox amino acid sequence showed two potential SH3 domains. The functional domains are highly conserved in many animals, though the sequence of the components of the black rockfish showed low homology with that of mammals. The deduced amino acid sequence of the black rockfish p47 phox was similar to those of the carp (60.4%), zebrafish (59,2%), rainbow trout (68.5%), xenopus (55.2%), mouse (54.2%), rabbit (54.5%), rat (53.7%), and chicken (50.9%). The expression of the rockfish p47 phox molecule was induced in peripheral blood leukocytes (PBLs) from 1 to 12 h following LPS stimulation, with a peak at 6 h after the stimulation, and which increased at 1, 3, and 12 h after treated with Poly I:C compared with the control. The rockfish p47 phox gene was expressed in various tissues of healthy fish. The level of p47 phox expression was high in the PBLs, kidney and spleen.

• Parasites, Hosts and Diseases
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• v.54 no.1
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• pp.21-29
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• 2016

The sodium hydrogen exchanger 1 (NHE1), which functions in maintaining the ratio of $Na^+$ and $H^+$ ions, is widely distributed in cell plasma membranes. It plays a prominent role in pH balancing, cell proliferation, differentiation, adhesion, and migration. However, its exact subcellular location and biological functions in Toxoplasma gondii are largely unclear. In this study, we cloned the C-terminal sequence of T. gondii NHE1 (TgNHE1) incorporating the C-terminal peptide of NHE1 (C-NHE1) into the pGEX4T-1 expression plasmid. The peptide sequence was predicted to have good antigenicity based on the information obtained from an immune epitope database. After induction of heterologous gene expression with isopropyl-b-D-thiogalactoside, the recombinant C-NHE1 protein successfully expressed in a soluble form was purified by glutathione sepharose beads as an immunogen for production of a rabbit polyclonal antiserum. The specificity of this antiserum was confirmed by western blotting and immunofluorescence. The antiserum could reduce T. gondii invasion into host cells, indicated by the decreased TgNHE1 expression in T. gondii parasites that were pre-incubated with antiserum in the process of cell entry. Furthermore, the antiserum reduced the virulence of T. gondii parasites to host cells in vitro, possibly by blocking the release of $Ca^{2+}$. In this regard, this antiserum has potential to be a valuable tool for further studies of TgNHE1.

• Journal of Life Science
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• v.21 no.10
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• pp.1487-1493
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• 2011

E. tarda, a fish pathogen, can survive in seawater under relatively high salt conditions as well as in fish under physiological salt conditions. Bacterial growth under different salt concentrations may influence the expression of genes involved in bacterial structure and physiology. The growth rate of E. tarda culture in high salt (3.5% NaCl) was similar to that in low salt (1.0% NaCl, physiological salt concentration). Interestingly, the strain moved much faster in low salt conditions than in high salt conditions. Electron microscopic observation demonstrated that the bacterial cells grown in high salt had less or no flagellation. Obvious flagellation was observed in the parental strain E. tarda CK41 grown in low-salt condition. Two putative genes coding flagellin were identified in the E. tarda genome sequences. The amino acid sequence comparison of each gene revealed 93% identities. A flagellin gene was PCR amplified and cloned into a cloning vector. Using an E. coli protein expression system, a part of flagellin protein was overexpressed. Using the purified protein, an anti-flagellin antibody was raised in the rabbit. Immunoblot analyses with flagellin specific antibody demonstrated that E. tarda CK41 expressed falgellin in low salt conditions, which is consistent with the results seen in motility assay and microscopic observation. This is the first report of salt regulated flagella expression in E. tarda.

• Korean Journal of Plant Tissue Culture
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• v.24 no.1
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• pp.63-69
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• 1997

Erythropoietin (EPO) is a glycoprotein that mediates the growth and differentiation of erythroid progenitors. In order to produce recombinant human erythropoietin in tobacco plant, the EPO genomic DNA (5.4 kb) was cloned into plant expression vectors, pBI$\Delta$GUS121, pBD$\Delta$GUS121 and pPEV-1, and introduced in Nicotiana tabacum (var. Xanthi) via Agrobacterium tumefaciens-mediated transformation. After selection on MS media containing kanamycin (Km), 10 Km-resistant plants were obtained per each construct. The correct integration of EPO genomic DNA in the genome of transgenic plant was confirmed by polymerase chain reaction (PCR). Northern blot showed that transcripts of 1.8 kb length were produced in leaves of the plants, but there was no difference of mRNA amount according to promoter number and 5'-untranslated sequence (UTS). The proteins obtained from leaves of transgenic plants were immunologically detected by Western blot using rabbit anti-human EPO polyclonal antibody. The expressed protein appeared as smaller band of apparent mass of 30 kDa as compared to the EPO protein from human urine (37 kDa), suggesting that the modification (glycosylation) system in tobacco plant might be different from that of mammalian cells.