摘要:

A new monoclonal antibody with specificity for s-triazine herbicides was prepared using a tertbutyl-s-triazine hapten. An assay was developed, employing covalently immobilized hapten and monoclonal antibody labeled with horseradish peroxidase. This assay system had a detection limit of 0.01 w gl−1cyanazine, with a coefficient of variation less than 3%. Analysis on three different spiked water types showed an average recovery of 101% at 0.1 w gl−1cyanazine. Cross-reactions were found for atrazine, terbuthylazine and propazine in the range 18-62%. This immunoassay is therefore capable of detecting four different s-triazine herbicides at concentrations well below the limit value for drinking water of 0.1 w gl−1stipulated by the EEC Council Directive on drinking water.

ISSN:0954-0105    

DOI:10.1080/09540100020008128

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The effect of non-reducing sugars (sucrose, lactose and trehalose), complex carbohydrates (cyclodextrin and dextran), infant formula or egg yolk on the stability of purified chicken IgY was evaluated under different conditions. Regardless of the protectant that was used, about 20% of the activity of IgY was lost during freeze-drying except in the presence of infant formula where the loss of IgY activity was approximately 75%. The lowest loss of activity (10%) was observed when no protectant was used. Trehalose was the best protectant followed by cyclodextrin and infant formula when IgY was stored for 6 or 14 weeks at different temperatures. Sucrose, lactose and dextran were not effective as protectants under these conditions. IgY activity was completely lost after pepsin treatment in the presence of sugars or complex carbohydrates while 34 and 40% of its activity was recovered when treated in the presence of infant formula and egg yolk, respectively. IgY was fairly stable after trypsin treatment with the recovery of residual activity being between 75–100% depending on the protectant. Finally, the effect of heat treatment on the stability of aqueous solutions of IgY was evaluated. IgY was stable at 50, 60 or 70°C while complete loss of IgY activity was observed at 80 and 90°C in the presence of all protectants except infant formula and egg yolk were about 5% residual activity was observed. These results demonstrate that the addition of different compounds to IgY during freeze-drying or storage at different temperatures or subjecting them to enzyme treatments provided varying and in most cases considerable protection against loss of biological activity.

ISSN:0954-0105    

DOI:10.1080/09540100020008137

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Sandwich ELISAs have been produced capable of detecting 1250 ppm ruminant and porcine heat stable proteins, which have been heated to 130°C, 2.7 bar (absolute pressure), for 30 min and incorporated into compound animal feedstuffs (CAFs). Removal of most of the proteins derived from CAFs and rendered animal material by ammonium sulphate precipitation, followed by concentration of the specific heat stable proteins for species testing, proved to be of considerable benefit in amplifying test sensitivity (GB Patent 9317199.9, 18 August 1993; World Patent PCT/GB94/01715, 4 August 1994). Increased sensitivity was also achieved by both pre-heating the sample prior to protein extraction to overcome problems attributed to the presence of oils or fats, and optimising ELISA incubation stages. Occasional false positives, resulting from non-specific binding of lectins in plant material such as salseed, are identified through the use of a separate ELISA utilising non-immune sera.

ISSN:0954-0105    

DOI:10.1080/09540100020008146

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Sandwich ELISAs have been produced to detect ruminant and porcine heat stable proteins which have been heated to 130°C, 2.7 bar (absolute pressure), for 30 mins and incorporated into compound animal feedstuffs (CAFs). Sample preparation involves heat treatment, removal of CAF proteins and analyte concentration. The test system incorporates a separate ELISA to detect non-specific binding of certain plant derived CAF components, each of which are identified. Both ruminant and porcine heat stable antigens are detected at a concentration of 1250 ppm. %CVs obtained within assay were 6.97% and between assay 9.07%. The maximum calculated false negative rate over 3 years of routine operation of the ELISAs was <1%. Each assay plate incorporates 12 negative controls permitting an additional 3SD calculation to overcome any in-plate variation.

ISSN:0954-0105    

DOI:10.1080/09540100020008155

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

PCR amplification analysis with pediocin PA-1 (pedA1) specific primers, a gene probe covering the pedA1 structural gene, and an immunological probe based on anti-peptide antibodies with predetermined specificity for pedA1, have been evaluated for pedA1 structural gene detection and quantification of bacteriocin production in Pediococcus acidilactici strains of meat origin. PCR products were obtained from colonies and purified plasmid DNA. The gene probe was used in dot-blot and colony-blot hybridization analysis. The production of pedA1 was evaluated by a non-competitive indirect ELISA (NCI-ELISA), a competive indirect ELISA (CI-ELISA), a competitive direct ELISA (CD-ELISA), and by immunoblotting. The approaches taken in the generation and performance of the reported probes could be useful for the rapid detection and identification of other bacteriocin-producing lactic acid bacteria (LAB) from many substrates and reservoirs and for quantification of bacteriocin production in food and environmental isolates and heterologous hosts.

ISSN:0954-0105    

DOI:10.1080/09540100020008164

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Thirty-six Holstein bull calves were fed experimental milk replacers (454 g/day–1) containing 20% crude protein and 20% fat. Milk replacers contained no additives, antibiotics (800 mg neomycin (as neomycin sulfate) and 400 mg oxytetracycline daily replacing dried whey, or 3.3% spray dried bovine plasma replacing whey protein concentrate. Calves were orally challenged with approximately 108 colony forming units (CFU) of enterotoxigenic Escherichia coli on day 3. No veterinary treatments or supportive therapy were provided during the study. Calf body weight (BW) was determined weekly and average daily BW gain was calculated. Clinical scores were determined daily for fecal consistency, attitude and hydration. All clinical scores responded to oral E. coli challenge. Provision of antibiotics and animal plasma had no effect on fecal consistency but improved attitude and hydration scores, body weight gain and tended to reduce overall mortality. Spray dried animal plasma appears to be a viable alternative to antibiotics in calf milk replacer applications.

ISSN:0954-0105    

DOI:10.1080/09540100020008173

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor