• Molecules and Cells
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• v.27 no.5
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• pp.577-582
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• 2009

The development of a high-throughput functional genomic screening provides a novel and expeditious approach in identifying critical genes involved in specific biological processes. Here we describe a cell-based cDNA screening system to identify the transcription activators of BiP, an endoplasmic reticulum (ER) chaperone protein. BiP promoter contains the ER stress element which is commonly present in the genes involved in unfolded protein response (UPR) that regulates protein secretion in cells. Therefore, the positive regulators of BiP may also be utilized to improve the recombinant protein production through modulation of UPR. Four BiP activators, including human UDP-glucose:glycoprotein glucosyltransferase 1 (HUGT1), are identified by the cDNA screening. Overexpression of HUGT1 leads to a significant increase in the production of recombinant erythropoietin, interferon ${\gamma}$, and monoclonal antibody in HEK293 cells. Our results demonstrate that the cDNA screening for BiP activators may be effective to identify the novel BiP regulators and HUGT1 may serve as an ideal target gene for improving the recombinant protein production in mammalian cells.

• Journal of Sensor Science and Technology
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• v.19 no.6
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• pp.456-461
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• 2010

The detection of C-reactive protein(CRP) using self-assembled monolayer(SAM) was investigated by a portable surface plasmon resonance(SPR) sensor system. The CRP is a biomarker for the possible cardiovascular disease. The SAM was formed on gold(Au) surface to anchor the monoclonal antibody of CRP(anti-CRP) for detection of CRP. Sequence injection of the anti-CRP and bovine serum albumin(BSA) into the sensor system has been carried out immobilize the antibody and to prevent non-specific binding. The portable SPR system has two flow channels: one for the sample measurements and the other for the reference. The output SPR signal was increased with the injection of the anti-CRP, BSA and CRP due to binding of the proteins on the sensor chip. The valid output SPR signals was linearly related to the critical range of the CRP concentration. The experimental results showed the feasibility of the portable SPR system with newly developed SAM to diagnose a risk of the future cardiovascular events.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.2
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• pp.130-135
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• 2000

The characteristics of two different modes of perfusion culture, intermittent and continuous bleedings, were investigated by culturing the hybridoma cells producing von Willebrand Factor (vWF) monoclonal antibody (McAb) in a 15 L bioreactor without clogging the filter. Both culture methods exhibited similar profiles of cell density and metabolite concentrations during the culture period at the cell concentration of around 1${\times}$107 cells/mL. When the perfusion rate was increased, the intermittrnt bleeding culture showed problems of ammonia accumulation and decrease of cell viability. The continuous bleeding culture in terms of nutrient consumption and metabolite production kinetics. But the analysis of specific oxygen consumption rate showed that the specific oxygen consumption rate of intermittent bleeding culture was similar to that of exponential growth phase. The continuous bleeding culture showed higher specific oxygen consumption rate of intermittent bleeding culture. finally we proved the possibility of long-term operation of continuous bleeding culture and produced approximately 40 g of vWF McAb in a 15L bioreactor after one-month operation.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.4
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• pp.2383-2386
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• 2013

Senescence marker protein 30 (SMP30), a hepatocellular carcinoma (HCC) associated antigen, was earlier shown by our research group to be highly expressed in HCC paracancerous tissues, but have low levels in HCC tissues. In order to detect anti-SMP30 antibody in serum of HCC patients, we established pET30a-SMP30 and pColdIII-SMP30 expression systems in Escherichia coli. However, the expression product was mainly in the form of inclusion bodies. In this research, we used several combinations of chaperones, four molecular chaperone plasmids with pET30a-SMP30 and five molecular chaperone plasmids with pColdIII-SMP30 to increase the amount of soluble protein. Results showed that co-expression of HIS-SMP30 with pTf16, combined with the addition of osmosis-regulator, and a two-step expression resulted in the highest enhancement of solubility. A total of 175 cases of HCC serum were studied by ELISA to detect anti-SMP30 antibody with recombinant SMP30 protein. Some 22 were positive and x2 two-sided tests all showed P>0.05, although it remained unclear whether there was a relationship between positive cases and clinical diagnostic data.

• Microbiology and Biotechnology Letters
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• v.17 no.1
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• pp.19-23
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• 1989

A sequential system composed of hydroxylapatite chromatography and gel permeation chromatography was developed to purify the IgM type monoclonal antibody against the colon cancer cell SC-1 from the ascitic fluid of mice injected with the murine hybridoma CH07E02. In the hydroxylapatite chromatographic step the band dilution could be reduced by controlling the gradient and flow rate of the eluent, the sodium phospate buffer, the optimum values for these variables being 5.82$\times$10$^{-3}$M/cm and 0.2$m\ell/\textrm{cm}^2$/min, respectively. A degree of purity better than 99.99% as judged from silverstaining of the SDS-PAGE bands, was obtained by adding the gel permeation chromatographic step in tandem.

• Journal of Microbiology and Biotechnology
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• v.23 no.8
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• pp.1047-1054
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• 2013

Witches' broom of lime is a disease caused by Candidatus Phytoplasma aurantifolia, which represents the most significant global threat to the production of lime trees (Citrus aurantifolia). Conventional disease management strategies have shown little success, and new approaches based on genetic engineering need to be considered. The expression of recombinant antibodies and fragments thereof in plant cells is a powerful approach that can be used to suppress plant pathogens. We have developed a single-chain variable fragment antibody (scFvIMP6) against the immunodominant membrane protein (IMP) of witches' broom phytoplasma and expressed it in different plant cell compartments. We isolated scFvIMP6 from a naïve scFv phage display library and expressed it in bacteria to demonstrate its binding activity against both recombinant IMP and intact phytoplasma cells. The expression of scFvIMP6 in plants was evaluated by transferring the scFvIMP6 cDNA to plant expression vectors featuring constitutive or phloem specific promoters in cassettes with or without secretion signals, therefore causing the protein to accumulate either in the cytosol or apoplast. All constructs were transiently expressed in Nicotiana benthamiana by agroinfiltration, and antibodies of the anticipated size were detected by immunoblotting. Plant-derived scFvIMP6 was purified by affinity chromatography, and specific binding to recombinant IMP was demonstrated by enzyme-linked immunosorbent assay. Our results indicate that scFvIMP6 binds with high activity and can be used for the detection of Ca. Phytoplasma aurantifolia and is also a suitable candidate for stable expression in lime trees to suppress witches' broom of lime.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.2
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• pp.273-279
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• 2015

Leptospiral lipopolysaccharide (L-LPS) has shown potency in activating toll-like receptor 2 (TLR2) in pig fibroblasts (PEFs_NCC1), and causes the expression of proinflammatory cytokines. However, the stimulation by L-LPS was weak eliciting the function of TLR2 sufficiently in pig innate immunity responses during Leptospira infection. In this study, the immune response of pig embryonic fibroblast cell line (PEFs_SV40) was investigated and was found to be the high immune response, thus TLR2 is the predominate receptor of L-LPS in pig cells. Further, we found a strategy using the antibody against L-LPS, to prevent L-LPS interaction with TLR2 in pig cells which could impact on immune activation.

• Archives of Pharmacal Research
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• v.21 no.2
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• pp.128-134
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• 1998

Nitric oxide synthase, NOS (EC.1.14.13.39), was purified from bovine pancreas over 5,500-fold with a 7.6% yield using 30% ammonium sulfate precipitation, and $2^1$,$5^1$-ADP-agarose and calmodulin-agarose affinity chromatography. The purified bovine pancreatic NOS (bpNOS) showed a single band on SDS-PAGE corresponding to an apparent molecular mass of 160 kDa, whereas it was 320 kDa on non-denaturating gel-filtration. This indicated a homodimeric nature of the enzyme. The specific activity of the purified bpNOS was 31.67 nmol L-citrulline fored/mtn/mg protein and an apparent $K\textrm{m}$ for L-arginine was 15.72 $\mu\textrm{M}$, The enzyme activity was dependent on $Ca^{2+}$ and calmodulin, and to a lesser extent on NADPH, FAD and FMN. $H_4B$ was not required as a cofactor for the activity. In an inhibition experiment with L-arginine analogues, $N^G$-nitro-L-arginine (NNA) had the most potent inhibitory effect on bpNOS, and $N^{G}$, $N^{G1}$-dimethyl-L-arginine (symmetric; sDMA) did not have any inhibitory effect. Immunohistochemical analysis of the bovine pancreas using brain type NOS antibody (anti-bNOS antibody) revealed that acinar cells showed strong immunoreactivity against the antibody.

• Journal of Microbiology and Biotechnology
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• v.9 no.3
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• pp.376-380
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• 1999

Constructs, encoding a single-chain variable fragment of a catalytic antibody 4f4f (scFv-4f4f) with glycosidase activity, were made by combining the coding sequences for the heavy and light chain variable domains with a sequence encoding a linker (GGGGS). Using three different plasmid systems, single-chain antibodies were expressed separately in Escherichia coli, demonstrating significant differences in the expression level and amounts in soluble form of the recombinant protein. The protein expression from pET3a-scFv-4f4f was up to 20% of the total soluble proteins and, more importantly, the proteins were mostly found in a soluble form. An SDS-PAGE analysis of the purified single-chain proteins, yielding higher than 5mg from a 1-1 culture, showed a single band corresponding to its molecular weight of 29,100. A preliminary study shows that the expressed scFv-4f4f is catalytically active. The catalytic parameters for the hydrolysis of p-nitrophenyl-$\beta$-D-glucopyranoside by scFv-4f4f are being investigated.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.286-290
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• 2011

Ginsenoside Rg3 was reported to have important biological activities. We demonstrate conjugation and quantification procedures of ginsenoside Rg3 to gold nanoparticles for future biological and medical applications. Ginsenoside Rg3 was conjugated to spherical gold nanoparticles using a bifunctional heptaethylene glycol linker. The sulfhydryl group of heptaethylene glycol was adsorbed onto gold nanoparticles, and carboxylic acid end of heptaethylene glycol was bonded through a hydroxyl group of Rg3 via ester bond formation. The conjugation of Rg3 was characterized with various spectroscopic techniques, high resolution-transmission electron microscopy, and using Rg3 monoclonal antibody. The Rg3- functionalized gold nanoparticles were $4.7{\pm}1.0$ nm in diameter with a surface charge of -4.12 mV. The total number of Rg3 molecules conjugated to a 3.6 mL solution of gold nanoparticle was determined to be $9.5{\times}10^{14}$ corresponding to ~6 molecules of Rg3/gold nanoparticle. These results suggest that ginsenoside Rg3 is successfully conjugated to gold nanoparticles via heptaethylene glycol linker. The quantification was performed by using Rg3 monoclonal antibody without interference of gold's intrinsic color.