摘要:

Polyclonal antisera against streptomycin were prepared by using a streptomycin‐oxime derivative coupled to bovine serum albumin for the immunization of rabbits. The specificity and sensitivity of these antibodies were tested in a competitive assay using a streptomycinenzyme conjugate (prepared by coupling a streptomycin‐hydrazone derivative to horseradish peroxidase) in a double antibody solid phase technique. The only detectable cross‐reactivity of the assay system with other aminoglycoside antibiotics and other substances similar in structure was shown to be with dihydrostreptomycin of about 148.7%. The detection limit in buffer solution was 0.6 ng ml‐1for streptomycin and 0–4 ng ml‐1for dihydrostreptomycin. Employing rapid sample preparation procedures, streptomycin and dihydrostreptomycin were detected in milk at levels as low as 6 and 0.8 ng ml‐1respectively.

ISSN:0954-0105    

DOI:10.1080/09540109309354785

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Among three newly prepared monoclonal anti‐aflatoxin M1antibodies, named AM.1, AM.2 and AM.3, both AM.1 and AM.3 possessed high specificity and sensitivity towards aflatoxin M1, while AM.2 exhibited lower specificity. Employing AM.3 and horseradish peroxidase‐labelled second antibody, an improved ELISA was developed with a detection limit of 1.0 pg ml‐1of aflatoxin M1in solution. The contents of aflatoxin M1in powdered milks suspended in water were assayed by the indirect ELISA. The detection limit was 5 pg g‐1dry weight, and no clean‐up procedures were required. The reliability of the present ELISA with monoclonal antibody AM.3 was confirmed with reference powdered milks for aflatoxin M1. A limited ELISA survey showed the presence of aflatoxin M1in commercial milk powders sampled in France, the US and Thailand at levels of 30–418 pg g‐1, and it was confirmed by an improved HPLC analysis.

ISSN:0954-0105    

DOI:10.1080/09540109309354786

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Infants who do not receive adequate amounts of breast milk are particularly susceptible to infections by intestinal pathogens. The milk of humans and domestic animals carries protective factors such as immunoglobulins and oligosaccharides that provide a significant amount of protection to the recipient. It has been proposed that the diet of infants at risk of intestinal infections could be supplemented with protective factors found in cows ‘ milk or eggs, particularly immunoglobulins. The evidence in support of supplementation of infant formula is reviewed, as well as some of the work in progress.

ISSN:0954-0105    

DOI:10.1080/09540109309354787

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Apple allergy, as well as allergies to nuts, stone fruits and other fruits and vegetables, is very common in patients with hay fever caused by birch pollen. The observed clustering of hypersensitivities is due to cross‐reactions of allergen‐specific IgE antibodies. In the case of apple allergy, patients frequently report that the symptoms are more severe after ingestion of mature fruits. We therefore investigated whether changes of IgE binding properties arose during the development of Boskoop and Golden Delicious apples. Using one tree for each strain, extracts were prepared from fruits at different states of maturity. Sera of patients allergic to birch pollen and apples were studied by means of non‐competitive and competitive ELISA (EAST and EAST inhibition) as well as by immunoblotting followed by absorption/reflection densitometry. The results of the three methods agreed closely and revealed that the allergenic potency increased strongly during maturation of Golden Delicious apples and to a lesser degree during ripening of Boskoop apples. The extract with the highest allergenic activity was obtained from mature Golden Delicious. The differences in the potency of IgE binding were due to the occurrence of an 18 kD allergen in Golden Delicious apples, whereas only very low amounts of this protein were detected even in extracts of mature Boskoop.

ISSN:0954-0105    

DOI:10.1080/09540109309354788

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

For the easy and rapid detection of staphylococcal enterotoxins (SE) A, B, C1, D and E, a sandwich ELISA (enzyme‐linked immunosorbent assay) was developed using an activated nylon membrane with covalently bound antibodies as a solid phase. Strips coated with antibodies against one SE type were incubated with culture supernatants of strains of Staphylococcus aureus as well as with the extracts of food previously contaminated with SE. The assay of bound toxin was performed using horseradish peroxidase labelled antibodies which were partly purified by affinity chromatography. After addition of 3,3’,5,5'‐tetramethylbenzidine, a distinct blue dot developed in the case of positive samples. The detection limit for individual SE is in the range of 0.5 ng ml‐1to 1 ng ml‐1. A semi‐quantitative evaluation is possible without any special reading equipment. The test can be done within 2 h, sample preparation excluded. While milk needed no extraction, in the case of minced meat or noodles, homogenization with 1.5 or 2 volumes of phosphatebuffered saline followed by centrifugation for 20 min at 10 000 ×gand 4° C proved to be adequate. Interferences by constituents of the food extracts were not observed. The results showed good agreement with those of the microtiter plate ELISA and also with those of a commercially available SE ELISA kit.

ISSN:0954-0105    

DOI:10.1080/09540109309354789

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0954-0105    

DOI:10.1080/09540109309354784

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor