• Microbiology and Biotechnology Letters
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• v.22 no.4
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• pp.430-435
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• 1994

In order to develop an enzyme-linked immunosorbent assay (ELISA) for zearalenone (ZEA) in corn, we produced antisera by immunizing rabbits with ZEA-6'-carboxymethyloxime-BSA, purified polyclonal anti ZEA antibodies, and subsequently established a competitive indirect ELISA. The antibodies showed low cross-reactivity of 9.6~1.4% against ZEA analogues such as $\alpha$-zearalenol, $\beta$-zearalenol, $\alpha$-zearalanol, and $\beta$-zearalanol. From the standard curve of the ELISA for ZEA in corn, the detection range was found to be 0.3~1, 000 ng/ml. When artificially contaminated corns were assayed by the ELISA, the average recovery of ZEA spiked to 30~1, 000 ng/g was 109% (96~123%), although that of ZEA spiked to 10 ng/g was somewhat high (258%). The average coefficient of variation (CV) of the recovery was 18.0% (0.9~28.3%). When 9 corn samples naturally contaminated were assayed 3 times, the average CV of the determinitions was 27.7% (9.3~52.4%). Therefore, the ELISA was elucidated to be a practical tool for the detection of ZEA of 30 ng/g and more from corn.

• Journal of Food Hygiene and Safety
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• v.8 no.4
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• pp.205-214
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• 1993

The monoclonal antibody to chloramphenicol(CAP) was produced to develop an enzyme-linked immunosorbent assay(ELISA) for residual CAP. An immunogen(CAP-BSA) was prepared by immunogen, antibody titer was measured by indirect ELISA. Spleen cells form the immunized mouse were fused with SP2/OAg14 myeloma cells. Among hybridomas selected in HAT media, 6 clones shown high antibody titer to CAP were subjected to cloning by limit dilution, and all of the monoclonal antibodies(MCA1, 2, 3, 4, 5, 7 and 9) produced by each clone were identified as IgG1 by ELISA isotyping analysis. Competitive ELISA condition was established by using the purified monoclonal antibody MCA1 as primary antibody and CAP-HSA conjugate as coating antigen. Standard curve of CAP(n=28) showed that the lowest detection limit of CAP is 20ng/ml level. The cross-reactivities of the 6 monoclonal antibodies showed that CAP sodium succinate. CAP base, P-nitrophenol, and p-nitrobenzyl alcohol were 89∼178, 0.050∼2.237, 0.056∼0.794 and 0.013∼7.939%, respectively. No cross-reactivities were observed with phenylalanine, tyrosine, glutamine, thiamphenicol, neomycin, streptomycin, gentamicin, sulfamethazine, sulfathiazole, chlortetracycline and p-aminobenzoic acid.

• BMB Reports
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• v.30 no.5
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• pp.326-331
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• 1997

To construct a competitive ELISA standard curve for the detection of glucose-6-phosphate debydrogenase (G6PD), we used highly purified native G6PD (nG6PD) as both immobilized and soluble antigens and anti-G6PD serum raised against nG6PD as antibody. The polystyrene cuvettes coated with nG6PD were challenged with a mixture of a limiting amount of anti-G6PD serum and various doses of nG6PD as competitors followed by incubation with alkaline phosphatase-anti-IgG conjugate. The competitive ELISA did not exhibit the typical sigmoidal dose-response curve characteristic of competition immunoassays under the optimal concentrations of antigen and antibody. The soluble nG6PD used as competitor failed to effectively inhibit the binding of antibodies to the immobilized nG6PD. The addition of NADP, a cofactor of G6PD enzyme, to coating buffer used for immobilizing nG6PD to the cuvettes and PBS-Tween-BSA buffer for diluting competitors did not improve the inhibition of antibody binding to immobilized nG6PD by soluble n/G6PD. The addition of BSA to coating buffer did not increase inhibition, either. Surprisingly, when partially active G6PD (paG6PD), obtained by repeated freeze-thawing, was used as competitor, the antibody binding to either immobilized nG6PD or immobilized paG6PD was inhibited 49-58%. We conclude that an effective competitive ELISA system with nG6PD enzyme and anti-G6PD serum for the detection of G6PD may not be established due to the poor inhibition of antibody binding to immobilized nG6PD by soluble nG6PD under the present assay conditions and that the inhibition may be improved by using an inactivated enzyme as competitor regardless of the type of immobilized antigen used. These results imply that the immobilized nG6PD may undergo denaturation upon binding to the polystyrene cuvettes and that our anti-G6PD serum may recognize denatured enzyme better than active enzyme.

• Korean Journal of Veterinary Research
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• v.37 no.3
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• pp.613-618
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• 1997

Direct competitive enzyme linked immunosorbent assay(ELISA) with monoclonal antibodies have been studied for quantitative determination of T-2 toxin from the mold corn. The T-2HS, T-2HS-BSA, T-2HS-HRP and monoclonal antibodies against T-2 toxin produced in the studies were qualified for quantitative ELISA test of T-2 toxin. The mean recovery rate from ground com spiked T-2 toxin was 83%. The meaning range of the T-2 test was 60ng to $2{\mu}g$. According to the recovery results with the com spiked T-2, the tests proved to be suitable in the screening of the moldy feed samples for the presence of T-2 toxin and will be able to become the basis of the ELISA test for the quantitative screening kits of T-2 toxin.

• Journal of Microbiology and Biotechnology
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• v.17 no.4
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• pp.681-684
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• 2007

An immunoassay method was developed to quantitatively detect phosphinothricin-N-acetyltransferase (PAT) encoded by the Bialaphos resistance (bar) gene in genetically modified (GM) pepper. The histidine-tagged PAT was overexpressed in Escherichia coli M15 (pQE3l-bar) and efficiently purified by $Ni^{2+}$ affinity chromatography. A developed sandwich enzyme-linked immunosorbent assay (S-ELISA) method (detection limit: $0.01{\mu}g/ml$) was 100-fold more sensitive than a competitive indirect ELISA (CI-ELISA) method or Western blot analysis in detecting the recombinant PAT. In real sample tests, PAT in genetically modified herbicide-tolerant (GMHT) peppers was successfully quantified [$4.9{\pm}0.4{\mu}g/g$ of sample (n=6)] by the S-ELISA method. The S-ELISA method developed here could be applied to other GMHT crops and vegetables producing PAT.

• Bulletin of the Korean Chemical Society
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• v.23 no.8
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• pp.1116-1119
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• 2002

Monoclonal antibodies have been generated against a generic hapten, ο,ο-diethyl ο-(5-carboxy-2-fluorophenyl) phosphorothioate, for the determination of organophosphorus (OP) pesticides in a class-specific manner. In an indirect competitive enzyme-linked immunosorbent assay (ELISA) format, employing a heterologous coating antigen, these monoclonal antibodies showed desirable properties for use in the class-specific determination, i.e., broad specificity and high sensitivity. The IC50 values of four commonly used ο,ο-diethyl OP pesticides were fairly uniform ranging from 0.1 to 0.3 ㎛/mL. The IC50 values of three ο,ο-dimethyl derivatives were between 0.3 and 1.4 ㎛/mL. These values, together with the limits of detection (LOD), were better, in terms of the specificity and sensitivity, compared with the values obtained previously with polyclonal antibodies.

• Biomedical Science Letters
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• v.3 no.2
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• pp.115-123
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• 1997

$\alpha$-Fetoprotein (AFP) has been a useful marker in screening and/or monitoring patients with hepatocellular carcinoma, gonadal germ cell tumor, gastric carcinoma and neural tube defects. In the present study, it was attempted to produce anti-human AFP polyclonal antibodies and to develop a competitive enzyme-linked immunosorbent assay (ELISA) for the measurement of AFP in human plasma and amniotic fluid. AFP was isolated from amniotic fluid using an isolation procedure consisting of affinity chromatography and preparative polyacrylamide gel electrophoresis. The antibody directed against AFP was raised in rabbits. Double immunodiffusion and Western blotting methods showed that the antiserum was highly specific, reacting with only AFP-containing samples. Standard curve was obtained by using purified AFP and specific antiserum. The assay sensitivity was 5ng/ml and the working range was 5~l,000ng/ml. The within-assay and between-assay coefficient of variance (CV) was 4.5% and 8.5%, respectively. These results indicate that the assay is valuable for the measurement of AFP and found to be simple, reproducible, and accurate.

• Korean Journal of Veterinary Research
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• v.38 no.2
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• pp.297-303
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• 1998

For the extraction and measurement of zearalenone in the corn, bean, wheat and barley contaminated with Fusarium graminearum, the zearalenone-oxime, zearalenone-oxime BSA and zearalenone monoclonal antibodies were studied to develop and apply the direct competitive enzyme linked immunosorbent assay (ELISA). The extraction range of zearalenone with the monoclonal antibodies produced in this experiment was 10ng to 500ng/g feed and the 50% inhibition value was 50ng/ml. The mean recoveries of zearalenone artificially spiked in the ground corn were 89%. The specificity of F-2 monoclonal antibody for the analogues was favorable for the direct competitive ELISA. The result of the experiment showed the zearalenone in the corn, bean, wheat and barely naturally contaminated with the mold would be suitable for extraction and measurement with the monoclonal antibodies.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.922-926
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• 2013

3,3',4,4'-Tetrachlorobiphenyl (IUPAC PCB77) is one of seven indicative polychlorinated biphenyls (PCBs) in the surface sediments. The current study presents a novel polyclonal antibody for the determination of the PCB77 using indirect competitive enzyme-linked immunosorbent assay. Under optimum conditions, PCB77 was determined within the concentration range of 0.01-100 ${\mu}g\;L^{-1}$, with a detection limit of 0.057 ${\mu}g\;L^{-1}$. The assays were tested for their cross-reactivity profiles using 3 selected congeners and 4 Aroclor products. The assays were highly specific for coplanar PCB congeners, but less specific for Aroclor1248. The spiked recoveries from five sediment samples were 86%-114% for PCB77 from ELISA, which were satisfactory. The current study demonstrated that the developed antiserum and immunoassay procedure can be used to detect PCB77 in environmental samples. The results of the sediment analysis were confirmed by conventional GC/ECD.

• Journal of Microbiology and Biotechnology
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• v.33 no.2
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• pp.228-234
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• 2023

In this study, the performance of a gold biosensor combined with light microscope imaging system (GB-LMIS) was comparatively evaluated against enzyme-linked immunosorbent assay (ELISA) for detecting Salmonella under simulated chilling condition. The optimum concentration of antiSalmonella polyclonal antibodies (pAbs) was determined to be 12.5 and 100 ㎍/ml for ELISA and GBLMIS, respectively. GB-LMIS exhibited a sufficient and competitive specificity toward three tested Salmonella among only. To mimic a real-world situation, chicken was inoculated with Salmonella cocktail and stored under chilling condition for 48 h. The overall growth of Salmonella under chilling condition was significantly lower than that under non-exposure to the chilling condition (p < 0.05). No significant differences in bacterial growth were observed between brain heart infusion and brilliant green broth during the enrichment period (p > 0.05). Finally, both GB-LMIS and ELISA were employed to detect Salmonella at every 2-h interval. GB-LMIS detected Salmonella with a competitive specificity by the direct observation of bacteria on the sensor using a charge-coupled device camera within a detection time of ~2.5 h. GB-LMIS is a feasible, novel, and rapid method for detecting Salmonella in poultry facilities.