摘要:

Monoclonal antibodies (MAbs) against lactucin and lactucopicrin (two of the bitter principles of chicory;Cichorium intybusL.) have been prepared. In competitive ELISA, the sera from mice immunized with keyhole limpet haemocyanin (KLH)‐lactucin and KLH‐ lactucopicrin have been screened for cross‐reactivity to various sesquiterpene lactones with a guaiane skeleton that are present in chicory, such as lactucin, 8‐deoxylactucin, and their 11β,13‐dihydro derivatives, and lactucopicrin. Mice showing low cross‐reactivity were used to produce hybridomas that were screened for cross‐reactivity in the same way. The screening resulted in a lactucopicrin‐specific hybridoma (no. 4H10) showing a low cross‐reactivity (≪1%)for lactucin, 8‐deoxylactucin and their 11β,13‐dihydro derivatives. From KLH‐lactucin immunized mice, hybridoma no. 9F12 showed the best characteristics, i.e. 25% cross‐reactivity to 8‐deoxylactucin and its 11β,13‐dihydro derivative, and a 10% cross‐reactivity to lactucopicrin. The affinity constants of MAbs nos 9F12 and 4H10 were 2.2X104and 2.8X105M‐1respectively. Chicory extracts spiked with free sesquiterpene lactones showed an inhibition level equal to the sum of the inhibition level of the extract and the level of sesquiterpene lactones added.

ISSN:0954-0105    

DOI:10.1080/09540109609354913

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Screening for residues of anabolic steroids frequently requires extraction from tissues and fluids before analysis. Chemical procedures for these extractions can be complicated, expensive to perform and not ideal for the simultaneous extraction of analytes with different solubilities. Extraction by multi‐immunoaffinity chromatography (MIAC) may be used as an alternative. Samples are passed through a column containing a range of antibodies immobilized on an inert support. The desired analytes are bound to their respective antibodies, washed and then eluted by a suitable solvent The purified extracts can then be incorporated into the analytical tests. The analytes that can be extracted presently are α‐nortestosterone, zeranol, trenbolone, diethylstilboestrol, boldenone and dexamethasone. Manually, the MIAC procedure is limited to about six columns per operator but by automating the process using a robotic sample processor (RSP), 48 columns can be run simultaneously during the day or night. The RSP has also been adapted to transfer extracts and reagents on to ELISA plates. The automated system has proved to be a robust and reliable means of screening large numbers of samples for anabolic agents with minimal manual input.

ISSN:0954-0105    

DOI:10.1080/09540109609354914

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Immunoassays based on microwells (for laboratory assay) and polystyrene tubes (for field assay) have been applied to the analysis of the herbicides, molinate and diuron, in field water samples. Development of a new immunoassay format for molinate, with detection limits of 0.5–1 ppb, enabled, for the first time, the direct analysis of molinate in water samples across the full range of usual field residue levels, without need for pre‐concen‐tration. A highly sensitive field assay for urea herbicides (diuron limit of detection of 0.15 ppb) has also been developed, based on a double‐layer coating with protein A and urea herbicide‐specific antibody. Each assay was only slightly affected by ions and turbidity, which are often problems in subsurface and surface water matrices respectively. For both formats of the molinate and diuron immunoassays, close correlations were obtained between herbicide levels determined by the immunoassay and by instrumental analysis, using field water samples.

ISSN:0954-0105    

DOI:10.1080/09540109609354915

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Brown trout (Salmo trutta) were captured from a headwater stream contaminated with moth‐proofing agents. Synthetic pyrethroid residues within the tissues were obtained by ultrasonic extraction and examined by gas chromatography‐mass spectrometry operated in the negative ion chemical ionization mode (GC/NCI‐MS). Both permethrin and cyfluthrin had been bioaccumulated by the fish and the mean concentrations ( ± standard deviation) recorded were 2046 ( ± 203) μg kg‐1and 25.4 ( ± 46.9) μg kg‐1respectively. The concentrations of these pyrethroids are the highest recorded for freshwater fish captured from a natural ecosystem. At the time of sampling, permethrin could be detected within the stream water (0.034 μg l‐1) while cyfluthrin could not. A mean relative bioconcentration factor of approximately 60 000 was derived for the brown trout which was also greater than any previously determined for freshwater fish. The fish tissue extracts were also analyzed through use of an ELISA for permethrin. The ELISA reported consistently lower concentrations than those obtained by GC/NCI‐MS. This was attributed to analyte losses during preparation of the sample extracts in a form suitable for incorporation into the ELISA. The concentrations obtained by ELISA were significantly correlated with those obtained by GC/NCI‐MS (R2= 0.985, n = 5). Overall, the ELISA appeared to be suitable for the detection of permethrin in fish when present at concentrations in excess of the maximum residue level suggested for many foods by the Commission of the European Economic Community.

ISSN:0954-0105    

DOI:10.1080/09540109609354916

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Gliadin quantification is of essential importance in foods for coeliac patients. Quantification of gliadins is affected by the thermal treatments usually employed in food processing. In order to study the influence of heating on immunochemical detection of gliadin, samples of wheat flour and dough were heated under different time‐temperature conditions (20 min at 100, 130 or 160°C). Ethanolic extracts (70%, ethanol/water, v/v) of treated samples were analyzed by electrophoresis in polyacrylamide gel at pH 3.1 (A‐PAGE) and the protein content quantified. Gliadin was measured by a competitive ELISA. Flour samples suffered no changes in the amount of protein extracted with 70% ethanol nor in the electrophoretic pattern of the extracts after treatments. A rise of 40% in immunochemical reactivity was observed when flour samples heated at 100 and 130°C were analyzed. Higher temperatures produced a drop in reactivity (20% below the original levels). When dough samples were analyzed, an important decrease in extracted protein was observed after the 130 and 160°C treatments. The electrophoretic pattern remained unchanged. A decrease of almost 90% in immunochemical reactivity was also observed after the 130 and 160°C treatments. Our results show that changes in the solubility and immunochemical reactivity of prolamins can lead to an over‐ or under‐estimation of the gliadin content depending on the thermal history and the nature of the sample.

ISSN:0954-0105    

DOI:10.1080/09540109609354917

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The performance of an immunoaffinity phase for the purification of cattle liver extracts containing clenbuterol or salbutamol is described. The capacities of the immunoaffinity phase were found to be 440 ng of clenbuterol and 270 ng of salbutamol per g solid phase when measured in phosphate‐buffered saline. The phase yielded greater than 75% recovery of clenbuterol from cattle liver extracts fortified at concentrations equivalent to 12 ng g‐1The capacity for salbutamol was found to be markedly affected by buffer type and the presence of sample matrix components in cattle liver extracts. Immunoaffinity‐purified cattle liver extracts were analyzed by high‐performance liquid chromatography with UV and fluorescence detection. The presence of matrix co‐extractives in the purified extracts was the main factor limiting the applicability of this procedure to the determination of these analytes at residue levels. The achievable detection limits were estimated to be more than 5 ng g‐1for both analytes. The behaviour of salbutamol on this immunoaffinity phase was rather more complex than the high capacity value alone indicates. The data reported here suggest that such capacity values, derived under ideal conditions, should be treated with caution unless supported by recovery data determined for real samples. This consideration may be more important for cross‐reacting analytes than for the primary antigen.

ISSN:0954-0105    

DOI:10.1080/09540109609354918

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Immunology: A comparative approach

ISSN:0954-0105    

DOI:10.1080/09540109609354919

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0954-0105    

DOI:10.1080/09540109609354912

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor