• Journal of Microbiology and Biotechnology
• /
• v.13 no.5
• /
• pp.794-799
• /
• 2003

Enzyme-linked immunosorbent assay (ELISA) was developed for the rapid detection of Fusarium species, known as harmful fungi in food. One of the hybridoma cell lines (lB8) which produced a monoclonal antibody (Mab) specific to Fusarium extracellular polysaccharide (EPS) was screened and the Mab was produced and purified. A detection limit of the sandwich ELISA against F. moniliforme EPS was $0.001\;\mu\textrm{g}/ml$ in the standard curve. Among the 59 strains tested, most Fusarium species showed hight reactivity with Mab lB8, even when the culture broths were diluted 100,000 times. On the other hand, the other genera, except A. versicolor and Trichoderma viride, had no reactivity. When 1 to $100\;\mu\textrm{g}$ of F. moniliforme EPS was spiked into rice, potato, and mandarine orange, the average recoveries were 151%, 84%, and 94%, respectively, determined by sandwich ELISA. The correlation coefficients between the EPS levels determined by sandwich ELISA and the dry mycelial weight of the liquid culture of F. moniliforme, as well as between the EPS and colony forming unit in solid culture of potato, were 0.97 and 0.91, respectively.

• Journal of Microbiology and Biotechnology
• /
• v.9 no.6
• /
• pp.764-772
• /
• 1999

To develop an enzyme-linked immunosorbent assay (ELISA) for detecting mold, we produced anti-mold polyclonal antibodies by immunizing extracellular polysaccharide (EPS) of Aspergillus flavus or Penicillium citrinum in rabbits subcutaneously. Using the purified antibody (Ab) and Ab-HRP conjugate, a sandwich ELISA for EPS was established. The standard curve of the ELISA showed the detection limit for P citrinum EPS to be $0.003{\;}\mu\textrm{g}/ml$. The cross-reactivities of the anti-P citrinum EPS Ab toward components of P citrinum such as EPS, liquid, and solid culture mycelium were 100, 10.5, and 0.58%, respectively, and those toward components of A. flavus such as EPS, liquid and solid culture mycelium, and spore were 300, 0.67, 0.29, and 0%, respectively. When the reactivities toward culture broths of 59 mold strains were tested by the sandwich ELISA, most of the Aspergillus (16 of 18) and Penicillium (14 of 16) strains along with one of the two Cladosporium strains gave positive signals in the culture broths even when diluted 1,000 fold, while the rest of species such as Fusarium, Absidia, Alternaria, and Candida gave negative signals. When the water extracts of 30 corn samples were analyzed by the sandwich ELISA, the EPS in the com could be detected in the concentration range of $0.1-1.6{\;}\mu\textrm{g}/g$.

• BMB Reports
• /
• v.29 no.3
• /
• pp.192-199
• /
• 1996

A rapid and sensitive method has been developed to detect a-fetoprotein (AFP) in human serum by a two-site sandwich enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies (MAbs) for human AFP within 1 h. To obtain the most sensitive and reliable MAbs. 12 kinds of MAbs (HPJ1 to HPJ12) as a capture antibody and 4 kinds of horseradish peroxidase (HRP) conjugated MAbs as a tracer antibody were investigated. Among these, only HPJ 10-HRP conjugated HPJ 1 (HPJ 10-HPJ $1^*$) and HPJ 11-HRP conjugated HPJ 10 (HPJ 11-HPJ $10^*$) were chosen as candidates based on the linearity of the standard curve and the sensitivity of the assay. To further characterize these two pairs. MAbs against human AFP were purified from hybridoma cells. conjugated with HRP. and then characterized to optimize the two-site sandwich ELISA The HPJ 10-HPJ $1^*$ pair showed a sensitivity of 1 ng/ml and a better reproducibility than the HPJ 11-HPJ $10^*$ pair when the human sera were incubated at $37^{\circ}C$ for 30 min. The results obtained for 480 randomly selected human sera showed 0~20 ng/ml of AFP values for the normal human sera. To test the utility of our kit, AFP concentrations were determined for 951 human sera (including 85 normal sera, 480 random blood sera, 213 HBsAg-positives. 50 anti-HCV antibody positives. and 47 malignant diseases) and compared with other commercially available AFP detecting kits. These results show that the present two-site sandwich ELISA method is a rapid, sensitive, and reliable procedure for detecting AFP in human serum.

• BMB Reports
• /
• v.30 no.6
• /
• pp.390-396
• /
• 1997

A sandwich-type enzyme-linked immunosorbent assay (ELISA) for the quantification of human apolipoprotein A-I (apoA-I) was developed using monoclonal antibodies. For this assay, we used three monoclonal antibodies to trap and detect apo A-I. HDAI16 and HDA15 monoclonal antibodies were used for trapping apoA-I and HDAI8 monoclonal antibody was for detecting apoA-I. These three monoclonal antibodies were produced by immunizing mice with high density lipoprotein (HDL) isolated from human plasma. By immunoblot analysis, these three monoclonal antibodies were specific to apoA-I and showed no cross-reactivities with other plasma proteins. The results of competition assays for epitope cross-reactivity test also verified that these monoclonal antibodies identified separate and distinct epitopes on HDL and apoA-I. Affinity constants of monoclonal antibodies were measured by ELISA. Their association constants ranged from $10^7$ to $10^8$ $M^{-1}$. For this assay, pure apoA-I was isolated by affinity chromatography using monoclonal antibodies. In this sandwich assay, the amount of HRP-labeled HDAI8 bound to apoA-I trapped by HDAI16 and HDAI5 was proportional to apoA-I concentration in the range of 0 to 500ng/ml. ApoA-I concentration in plasma was calculated from the linear regression equation of standard curve. The precision and reliability of the assays are reflected in the low intra-and interassay coefficients of variation that averaged 3.25% and 4.30%, respectively. This assay is sensitive, simple, reproducible, convenient in incubation interval, and does not use radioisotope: thus it can be widely applied in clinical laboratories.

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

• Applied Chemistry for Engineering
• /
• v.25 no.5
• /
• pp.544-547
• /
• 2014

In this study, an enzyme-linked immunosorbent assay (ELISA) and immuno-chromatographic technique were combined to fabricate immuno-strip sensors for the detection of Legionella pneumophila. The immuno-strip sensor was manufactured with four different membranes. A nitrocellulose membrane was used to immobilize capture antibody and generate signals due to the high affinity to antibodies, and glass fiber membranes were used as a conjugate release pad and a sample application pad. A cellulose membrane was used as an absorption pad to induce sample flow by the capillarity. Colorimetric signals produced by sandwich immuno-reaction and enzyme reaction could be analyzed qualitatively and quantitatively within 30 min. Under the given experimental conditions, sensor signals with L. pneumophila samples were observed qualitatively by naked eyes and measured quantitatively in a range of $1.3{\times}10^3-1.3{\times}10^6CFU/mL$ with a digital camera and home-made image analysis software.

• Journal of Microbiology and Biotechnology
• /
• v.14 no.2
• /
• pp.385-389
• /
• 2004

The antibody-mix sandwich enzyme-linked immunosorbent assay (Ab-mix sELlS A) system was developed in order to simultaneously detect the extracellular polysaccharide (FPS) of Aspergillus, Penicillium, or Fusarium species using one detection system. The detection limit and detection range of the Ab-mix sELISA towards EPS of Penicilliun citrinum were not changed, and those towards Fusarium moniliforme EPS were changed a little compared to that of individual sandwich ELISA [9, 10]. The fungal culture filtrates of Aspergillus and Penicillium species showed nearly similar reactivity towards Ab-mix sELISA as that of sELISA using the MAb lB8 alone [9]. Also, the fungal culture filtrates of Fusarium species showed nearly the same reactivity towards Ab-mix sELISA as that of sELISA using the MAb lB8 alone [10]. Thus, this ELISA system showed that the three genera of molds, Aspergillus, Penicillium, or Fusarium, which are three major important molds producing mycotoxins in food or agricultural commodities, could be detected at the same time, using one detection system.

• Biomolecules & Therapeutics
• /
• v.2 no.2
• /
• pp.120-125
• /
• 1994

We obtained the total protein antibodies of Saccharomyces cerevisiae KCTC 1720 and Escherichia coli K-12 from the rabbit and the guinea pig to determine the host-derived proteins which may be remained in biotechnological products. The protein concentration of rabbit antibodies was 4.05 mg/mι in the case of yeast, 7.14 mg/mι in the case of E. coli and that of guinea pig antibodies was 1.90 mg/mι in the case of yeast, 7.17 mg/mι in the case of E. coli, respectively. To determine remained host-derived proteins in biotechnological products which produced by the hosts, S. cerevisiae or E. coli, we used a sandwich enzyme linked immunosorbent assay method in 96 well microplate. When the method applied to determine the remained host-derived proteins in commercial biotechnological products, it detected less than 3.5 ng/vial in human growth hormone, less than 1 ng/vial in hepatitis B vaccine and interferon-${\gamma}$ and 2~23 ng/vial in interferon-$\alpha$. The method can be used to determine the remained host-derived protein in biotechnological products.

• Microbiology and Biotechnology Letters
• /
• v.10 no.3
• /
• pp.205-209
• /
• 1982

The enzyme-linked immunosorbent assay using the so-called "double-sandwich"technique was applied to determine Clostridium botulinum type F toxin. Polystyrene tubes were coated with horse anti-type F toxin serum and then toxin sample was added. The tubes were subsequently treated with rabbit anti-type F toxin IgG and sheep anti-rabbit serum IgG-horseradish peroxidase conjugate. By this technique, about 10 mouse intraperitoneal 50% lethal doses (ip LD/50/) of type F toxin could be detected. Low back-ground reading was achieved with the use of phosphate-buffered saline containing 0.05% Tween 20 and 1% bovine serum albumin as diluents of rabbit IgG and conjugate. Addition of EDTA in the diluents of toxin increased ELISA extinction value significantly. No cross-reaction was observed with botulinum type A and B toxin, but type E toxin gave sleight cross-reaction.

• Environmental Analysis Health and Toxicology
• /
• v.28
• /
• pp.16.1-16.8
• /
• 2013

Objectives Fish vitellogenin (VTG) is produced in the female liver during oogenesis through the estradiol cycle and produced in the male liver by endocrine disrupting chemicals (EDCs) such as alkylphenols. In this study, we propose that the VTG concentration in the pale chub could be detected using monoclonal antibodies and polyclonal antibodies against vitellin (Vn) in a VTG enzyme-linked immunosorbent assay (ELISA) system. Methods Monoclonal antibodies and polyclonal antibodies were produced using the Vn extracted from the matured ovum of the ovary. The VTG was extracted from the plasma of the male pale chub. The Vn and VTG were confirmed by measuring the molecular weight of their proteins using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the specificity of the antibodies was checked through western blotting methods. The assay system was validated with respect to optimal assay concentrations, specificity, recovery, and intra- and inter-assay variations. Results The Vn consisted of two protein bands with apparent molecular weights of 64 and 37 kDa. The SDS-PAGE indicated protein weights of 146 and 77 kDa in the VTG. The assay range was 15.6 ng/mL to 2,000 ng/mL, and the value of the intra- and inter-assay variations were within 10.0% and 14.7%, respectively. The recovery rate was $99.5{\pm}5.5%$. Conclusions A sandwich ELISA was developed that could be used to qualify the VTG of pale chub in screening for EDCs. Pale chub is an ideal species for observing estrogen activity in the environment because of its extensive habitat and extensive food chain. The ELISA developed here would be more favorable than those for other species for determining the effect of long-term food chain accumulation of EDCs in aquatic environments.