• Journal of Food Hygiene and Safety
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• v.28 no.3
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• pp.267-271
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• 2013

A survey of aflatoxin $B_1$ and ochratoxin A was conducted on dried red pepper and red pepper powder. Total number of 193 samples were collected from local markets in Incheon. The presence of aflatoxin $B_1$ and ochratoxin A was determined by high performance liquid chromatography (HPLC) with fluorescence detector using immunoaffinity column clean-up. The recovery rate of aflatoxin $B_1$ and ochratoxin A were more than 80% and the limits of quantification were 0.13 ${\mu}g/kg$ for aflatoxin $B_1$ and 0.30 ${\mu}g/kg$ for ochratoxin A. Aflatoxin $B_1$ was detected in 33 samples (17.1%) with a range of 0.14~9.67 ${\mu}g/kg$ and ochratoxin A was detected in 40 samples (20.7%) with a range of 0.31~3.31 ${\mu}g/kg$. These results show that the occurrence of aflatoxin $B_1$ and ochratoxin A in dried red pepper and red pepper powder tested in this study is low compared with the standard in Korea Food Code (10 ${\mu}g/kg$ as aflatoxin $B_1$ and 7 ${\mu}g/kg$ as ochratoxin A).

• Korean Journal of Food Science and Technology
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• v.41 no.3
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• pp.258-264
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• 2009

The principal objective of this study was to estimate the measurement uncertainty associated with determination of deoxynivalenol (DON), a mycotoxin generated by Fusarium strain, in food. In service of this goal, wheat as a food matrix was analyzed via high performance liquid chromatography-ultraviolet (HPLC-UV) detection using an immunoaffinity column for clean-up. The uncertainty sources in the measurement process were identified by sample weight, final volume, and sample concentration in extraction volume with components including standard stock solution, working standard solution, 5 standard solutions, calibration curve, matrix, and instrument. The expanded uncertainty for DON at a concentration of 300 ${\mu}g/kg$ was estimated as 71.62 ${\mu}g/kg$ using a coverage factor of two, which provides a confidence level of approximately 95%. The most influential component in the uncertainty sources was the recovery of the wheat matrix, followed by the calibration curve. These results indicate that all efforts may be directed toward reducing the uncertainties of the recovery of the wheat matrix and the calibration curve to obtain a reliable HPLC-UV method for DON analysis in wheat.

• Korean Journal of Food Science and Technology
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• v.45 no.3
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• pp.312-316
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• 2013

The objective of this study was to establish an analytical method to detect zearalenone (ZEA) in herbal medicines and their decoctions and investigate the ZEA transfer rate from raw materials of herbal medicines to their decoctions. Herbal medicines (Trichosanthis Semenm, Eucommiae Cortex, Rubi Fructus) spiked with a known concentration of ZEA were presoaked or unsoaked (as a pretreatment) and boiled for 3 h at $100^{\circ}C$ or autoclaved for 1 h at $121^{\circ}C$. The decoction and the remnants were separated, cleaned up with an immunoaffinity column, and analyzed using HPLC. Recoveries for decoctions and remnants were 68.39-83.68% and 72.91-80.25%, respectively. ZEA was not detected in the decoction, whereas it was found in the remnants. Although ZEA in the raw material of herbal medicines was not transferred into the decoction during heating and autoclaving, the continuous monitoring for ZEA in raw herbal medicines should be carried out for the safe ingestion and utilization of herbal medicines.

• Archives of Pharmacal Research
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• v.20 no.5
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• pp.396-403
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• 1997

In order to direct the form of the immune response in an antigen-specific manner, we constructed a fusion protein (OVA/IL12) that contained the T cell-dependent antigen, ovalbumin (OVA), covalently linked to murine interleukin-12 (IL-12). The OVA/IL12 protein was produced in a baculovirus expression system and was purified by anti-OVA immunoaffinity chromatography. The purified OVA/ILI2 protein displayed potent IL-12 bioactivity in an IL-12 proliferation assay. BALB/c mice immunized with the OVA/IL12 protein produced increased quantities of anti-OVA IgG2a antibody compared with mice immunized with recombinant OVA alone. Lymph node cells from the immunized mice with the OVA/IL12 protein produced large amounts of IFN-,Y when restimulated in vitro with OVA, while those from mice immunized with the OVA protein produced little or no IFN-.gamma.. In contrast, immunization with a mixture of OVA and free recombinant IL-12 also induced IFN-.gamma. production, which was not OVA-specific. These studies indicate that the OVA/IL12 fusion protein can induce OVA-specific, Th1-dominated immune responses, and that the covalent linkage of OVA and IL-12 confines the effect of IL-12 to OVA-specific cells.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.93-93
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• 1997

Analysis of protein is often frustrated by the inability to isolate large amounts of purified protein from a native source. To overcome this problem, fusion protein expression systems such as pGEX system have been widely used. Using pGEX system, the desired protein could be easily obtained in a large amount in E. coli, and then the fusion protein could be used for the study of the function of the given protein. To analyze and purify the GST fusion protein, anti-GST antibody could be used as one of the system of choice. However, the production and characterization of monoclonal anti-GST antibody has not been studied extensively yet. To produce monoclonal anti-GST antibody, GST was purified from E. coli transformed with pGEX-cs, one of the pGEX system and was used as an antigen. The monoclonal antibody was produced by fusion of the immunized spleen cells with SP2-0 myeloma cells. The antibody was characterized by ELISA, western blotting, etc. The monoclonal antibody produced in this study (mAb-GSTA) showed strong and specific immunoreactivity against not only GST but also GST-fusion proteins. Also, mAb-GSTA was successfully used for the immunoaffinity purification of the GST ${\beta}$-Rc.-third intracellular-loop fusion protein. The results of the present study suggest that mAb-GSTA may be used for the identification and purification of GST fusion proteins.

• Journal of Sensor Science and Technology
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• v.28 no.6
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• pp.355-359
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• 2019

Exosomes, known as nanoscale extracellular vesicles in the range of 30-150 nm, are known to contain clinically significant information. However, there is still insufficient information on exosomal membrane proteins for cancer diagnosis. In this work, we investigated the characteristics of the membrane proteins of exosomes shed by cultured breast cancer cell lines using a surface plasmon resonance (SPR) spectroscopy and pre-activated alkanethiols modified sensor chips. The antibodies of breast cancer biomarkers such as MCU-16, EpCAM, CD24, ErbB2, and CA19-9 were immobilized on the pre-activated alkanethiols surfaces without any activation steps. The purified exosomes were loaded onto each antibody surface. The affinity rank of the antibody surfaces was decided by the relative capture efficiency factors for the exosomes. In addition, an antibody with a relative capture efficiency close to 100% was tested with exosome concentration levels of 10⁴/µl, 10⁵/µl, and 10⁶/µl for quantitative analysis.

• BMB Reports
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• v.40 no.6
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• pp.959-965
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• 2007

Two isolectins (KML-IIU and the KML-IIL) were individually isolated from the previously reported Korean mistletoe lectin, KML-C, by using an immunoaffinity column. Molecular weights of the KML-IIU and the KML-IIL were 64 kDa and 60 kDa respectively. Both of the lectins were composed of heterogeneous A and B subunits linked with a disulfide bond, and showed the same carbohydrate-binding specificities for Gal and GalNAc. However, they are different not only in biophysical properties (glycosylation and amino acid compositions) but also bioactivities (cell killing and cytokine induction). The KML-IIL showed 17-145 times stronger in cytotoxicities to various human and mouse cancer cell lines than the KML-IIU. The KML-IIL also induced TNF-$\alpha$ secretion from mouse peritoneal macrophages 4.5 times better than the KML-IIU. The results demonstrated isolectins in Korean mistletoe were varied in bioactivities and the KML-IIL may be developed as an anti-cancer agent.

• Mycobiology
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• v.42 no.4
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• pp.339-345
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• 2014

During 2011~2013, a total of 729 samples for 19 types of medicinal plant were collected from Seoulyekryungsi in Seoul, Korea, and investigated for the presence of aflatoxins. The samples were analyzed using immunoaffinity column cleanup and high-performance liquid chromatography coupled to a fluorescence detector after post-column derivatization. Aflatoxins were found in 124 out of the 729 analyzed samples: 65 containing aflatoxin B1 (AFB1), 24 with aflatoxin B2 (AFB2), 15 with aflatoxin G1 (AFG1), and 20 samples with aflatoxin G2 (AFG2). The ranges for positive samples were $0.1{\sim}404.7{\mu}g/kg$ for AFB1, $0.1{\sim}10.0{\mu}g/kg$ for AFB2, $0.1{\sim}635.3{\mu}g/kg$ for AFG1, $0.1{\sim}182.5{\mu}g/kg$ for AFG2, and $0.1{\sim}1,043.9{\mu}g/kg$ for total aflatoxins. Most of the medicinal plant samples (721, 98.9%) were below legal limits, but 8 samples exceeded the legal limits of 10 and $15{\mu}g/kg$ established by the Korean standard for AFB1 and total aflatoxins (the sum of AFB1, AFB2, AFG1 and AFG2), respectively.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.472-477
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• 1996

Natural human epidermal growth factor (nhEGF) was purified from pregnant human urine by benzoic acid adsorption, DEAE-Sepharose ion exchange, and immunoaffinity chromatography. The purified nhEGF was further separated into four fractions using Bondapak C$_{18}$ HPLC system. Following characterization by Western blot analysis and double immu- nodiffusion, we found that each fraction corresponds to four derivatives of the nhEGF. For biological analysis of nhEGF, we optimized the labeling time and serum concentration for the incorporatioin of 5-bromo-2'-deoxy uridine (BrdU), a non-radioactive alternative for [$^{3}$H]-thymidine uptake, into NIH 3T3 cells. The DNA synthesis of NIH 3T3 cells was gradually increased at the nhEGF concentrations between 0.1 - 10 ng/ml in the Dulbecco's Modified Eagles Medium (DMEM) containing 0.2% Fetal calf serum (FCS). When we assayed the biological activity of four fractions, the activity of the second fraction was superior to that of the others. Based on the results from the HPLC analysis spiked with recombinant human epidermal growth factor (rhEGF) and amino acid sequencing, we concluded that the second fraction was nhEGF and the other three fractions were the derivatives of nhEGF. In addition, the proportion of nhEGF was approximately 46% is compared with that of the other three derivatives.

• BMB Reports
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• v.28 no.6
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• pp.504-508
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• 1995

The electrophoretic patterns of plasma membrane surface proteins of normal rat liver cells and rat hepatomas were compared in 10% non-denaturing and 7-15% gradient non-denaturing gel. Chemical carcinogens, 2-Me DAB (2-methyl-4-dimethylaminoazobenzene) and DENA (diethylnitrosamine), were used to induce hepatoma in rats. One protein which disappeared in hepatoma was identified in normal rat liver by non-denaturing gel electrophoresis. Rabbit antisera were raised against this specific protein, and the protein was purified by Sephacryl S-200 column and immunoaffinity chromatography using the purified antibody. The purified protein showed two bands of molecular weights approximately 50 $kD_{\alpha}$ and 52 $kD_{\alpha}$ by SDS-polyacrylamide gel electrophoresis, which reacted specifically with the antibody. However only one band was observed in non-denaturing gel and also in isoelectric focusing with a pI value of 6.6. This study showed the existence of an unique protein on the plasma membrane surface of normal rat liver cells which disappeared in rat hepatomas induced by chemical carcinogens.