摘要:

The mycotoxin deoxynivalenol (DON) is produced by the mold Fusarium graminearum and is found worldwide on cereal grains, in particular wheat and maize. Each year this compound, also known as 'vomitoxin' causes substantial losses to agricultural productivity. Three monoclonal antibodies were developed following the immunization of mice with a conjugate of DON and ovalbumin. One of these antibodies, produced by clone #22, was selected for the development of a competitive direct ELISA (CD-ELISA). This format consists of competition between a DON horseradish peroxidase conjugate (DON-HRP) and free DON for antibody attached to microwell plates. Color development in the assay was inhibited 50% (IC50) by 18 ng DON/ml in phosphate-buffered saline (PBS). The antibody from this clone showed strong cross-reactivity to 3-acetyl deoxynivalenol (3-Ac-DON), with an IC50of 2.9 ng ml−1Cross-reactivity to 19 other trichothecene mycotoxins was low. The CD-ELISA was applied to wheat spiked with DON over the range 0.01-10 w g/g and extracted with a 10-fold excess of PBS. The midpoint for color development in the assay using this extraction was 0.27 w g DON/g wheat. Recoveries over the range 0.05-5 w g/g averaged 88.7% with a coefficient of variation of 10.9%. This assay is sufficiently sensitive and rapid to permit the screening of DON in wheat below the US Food and Drug Administration advisory level of 1 ppm in human food.

ISSN:0954-0105    

DOI:10.1080/09540100050140722

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

We report the generation of an anti-idiotypic antibody, clone 12E12, against antisulfamethazine (SMZ) as a surrogate ligand for SMZ in immunoassay procedures. This has been achieved by using the primary monoclonal anti-SMZ antibody as an immunogen in hybridoma technology followed by screening of the resulting hybridromas for binding to the SMZ site of the primary anti-SMZ antibody. Characterization of a strong anti-idiotypic antibody of the betatype, clone 12E12, capable of mimicking SMZ, permitted the development of immunoassay formats for SMZ based on the idiotypic and anti-idiotypic approach and the direct measurement of SMZ content in diluted pig urine. The availability of the strong betatypic anti-idiotypic antibody acting as a surrogate ligand for SMZ enables antibodies to be labeled instead of ligands and offers interesting possibilities for the development of competitive type non-isotopic immunoassays for SMZ.

ISSN:0954-0105    

DOI:10.1080/09540100050140731

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A method for immunoassay analysis of the organochlorine insecticide, hexachlorocyclohexane (HCH) has been developed, based upon alkaline conversion in standards and samples to trichlorobenzenes. The trichlorobenzenes were detected through antisera developed to haptens containing either a trichlorobenzene or trichlorpyridine moiety, developed using the herbicides, 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and triclopyr, respectively. An enzyme conjugate based on 2,4,5-trichlorophenol provided most sensitive and specific detection. Although the assays cross-reacted with the herbicides, they did not suffer from the major disadvantage of extremely strong cross-reaction with cyclodiene organochlorines reported for a commercial HCH assay. The most sensitive assay had a lower detection limit of 20 w g l−1in drinking water and was applied to water and soil matrices.

ISSN:0954-0105    

DOI:10.1080/09540100050140740

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The allergenicity of four hazelnut varieties (Runde Römer, Levantiner, Neapler, Contorta) and different types of heat treated and stored hazelnuts was examined and compared by SDSPAGE/immunoblotting and EAST-inhibition experiments using sera of 19 hazelnut allergic individuals. The immunoblot and EAST-inhibition investigations of the four varieties revealed only slight differences with regard to the allergenic activities. Heat treatment at 100°C for up to 90 min had no influence on the allergenicity of hazelnut prote ins. The IgE binding activity of the main hazelnut allergens decreased after 15 min heat treatment at temperatures between 100 and 185°C and was no longer detectable at 170°C. A protein < 14 kDa appeared to be very stable to heat and could be detected even after treatment at 185°C. Microwave treatment and storage of ground hazelnuts up to 19 weeks at room temperature had no influence on the allergenicity of hazelnut proteins.

ISSN:0954-0105    

DOI:10.1080/09540100050140759

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

We developed an anti-immune complex (IC) ELISA applicable to direct determination of trace amounts of microcystins (MCs) in tap water. Comparison of two assay formats revealed that the use of anti-immune complex monoclonal antibody (MAB) in the coating step to trap anti-MC MAB–MC complexes improved the sensitivity as well as precision. The detection limit and quantitative range of the IC ELISA was 2 pg ml−1and 2–100 pg ml−1of microcystinLR (MCLR), respectively, indicating the most sensitive of all the methods for detecting MCs reported to date. Additionally, the IC ELISA maintained good reliability through its quantitative range, as evidenced by low coefficients of variation (5.0–10.8 and 4.9–10.2% for intra- and interassay, respectively). The IC ELISA showed good cross-reactivity to microcystin-RR and microcystin-YR, suggesting major MCs found in the environment can be detected by this method. Recovery tests in which quantitative range of MCLR were added to tap water resulted in a mean recovery of 99%, with a mean standard deviation of 5.7%; therefore the IC ELISA performed well in the analysis of tap water samples. ELISA analysis of tap water samples collected in China and Japan revealed that, among 17 samples tested, two samples collected in China were positive for MCs at 4.9–14 pg ml−1. These results suggest that the newly developed IC ELISA can be used to monitor trace amounts of MCs in tap water.

ISSN:0954-0105    

DOI:10.1080/09540100050140768

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A dot blot enzyme immunoassay was developed for detection of peanut proteins in foods based on the use of polyester cloth as the solid phase. Samples were spotted on polyester cloth pre-coated with anti-peanut antibodies (chicken IgY), and bound peanut proteins were detected by sequential reactions with peroxidase-conjugated anti-peanut antibodies and chromogenic substrate. This assay detected peanut proteins in a variety of foods, in some instances giving positive results with samples containing less than 1 ppm peanut protein.

ISSN:0954-0105    

DOI:10.1080/09540100050140777

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor