摘要:

A monoclonal antibody was obtained from a Balb/c mouse immunized with a conjugate prepared by the direct coupling of diazotized clenbuterol to bovine serum albumin. The antibody, characterized by γ1,κ isotype and an affinity constant of 3.5 × 108l mol‐1, is highly specific as its cross‐reactivity to structurally related molecules is less than 1%. A competitive ELISA for the detection of clenbuterol in horse and human urine was developed using this antibody.

ISSN:0954-0105    

DOI:10.1080/09540109609354898

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Halofuginone (Hal) is a coccidiostat used worldwide as a feed additive at a level of 3 ppm in the feed of broiler chickens. The analytical methods described in the literature to determine the levels of Hal in liver are very lengthy and time consuming. This study evaluated the usefulness of determining Hal in chicken serum with a competitive ELISA (cELISA). If a 4‐day withdrawal time could be determined by serum Hal levels, the method would greatly improve on the high‐performance liquid chromatography (HPLC) methods currently used for Hal detection in liver tissue. A modification of a previously developed HPLC method was used to validate the cELISA analysis of Hal in chicken serum. A serum matrix effect that afforded a higher sensitivity by the cELISA for the detection of Hal in chicken serum than in assay buffer or in highly diluted serum was observed. The sensitivity of the cELISA method improved when used in more concentrated serum. The chicken serum samples were evaluated by cELISA using a standard curve obtained in control chicken serum diluted two‐fold with assay buffer. Incurred levels of Hal in broiler chickens fed Hal‐HBr‐treated feed were detected in serum at withdrawal times of 2 and 6 h. At and after 24 h, the residues were not detected by immunoassay with a detection limit of 0.52 ppb or by HPLC with detection limit of 0.86 ppb. The instability of Hal in acidified serum and its potential for methanolysis in the HPLC method were overcome by using the cELISA methodology. Although the determination of Hal in chicken serum by immunoassay is fast, requiring no clean‐up steps, chicken serum cannot be used to determine the required 4‐day withdrawal time in broiler chickens because of the lack of residues in the serum at and after 24 h.

ISSN:0954-0105    

DOI:10.1080/09540109609354899

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The antigen‐binding domain of an antibody specific for the herbicide atrazine was cloned from hybridoma 4063–21–1 and expressed as a single‐chain antibody (scAb) in the vector pPM1‐His. The observed heavy and light chain gene sequences were consistent with those in subgroup VH I (B) and VK TV, as defined by the Kabat database of sequences. Subsequent expression in Escherichia coli strain XL‐1 Blue produced up to 0.3 μg of functional single‐chain antibody, from periplasmic protein preparations, per millilitre of culture. The scAb was purified as a monomer by immobilized metal chelate affinity chromatography via a hexa‐histidine tail or as a dimer by antibody affinity chromatography. The functionality and specificity of the recombinant antibody was confirmed by binding to an atrazine‐bovine serum albumin conjugate and free atrazine and simazine in a competition ELISA. This is the first example of the production and purification of a recombinant antibody that retains antigen binding for a triazine herbicide.

ISSN:0954-0105    

DOI:10.1080/09540109609354900

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The aim of this study was to develop a method to identify cows illegally treated with bovine somatotropin (BST). Using the Western ligand blotting technique, BST treatment was shown to cause a dramatic decrease of IGF‐BP‐2 in the serum of treated cows. Measurement of the insulin‐like growth factor‐binding protein‐2 (IGF‐BP‐2) concentration in cow plasma could thus be a good way to identify BST‐treated animals. In order to develop an immunoassay specific for bovine IGF‐BP‐2, polyclonal antibodies against synthetic peptides of bovine IGF‐BP‐2 were produced. Three peptides were chosen in the [150–190] region of the molecule, which display no identity with other IGF‐BPs in serum: [154–165], [171–184] and [163–176]. Two antisera were obtained which reacted specifically with the entire bovine IGF‐BP‐2 molecule, both of which came from rabbits immunized with the [163–176] peptide.

ISSN:0954-0105    

DOI:10.1080/09540109609354901

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Polyclonal antibodies against the 68 kDa esterase ofFusarium sporotrichioideswere produced by immunizing rabbits with the enzyme, which had been partially purified by ammonium sulfate precipitation, DEAE‐Sephadex anion exchange chromatography and gel electroelution. The antiserum was further purified by passage through an affinity column armed with proteins obtained from the affinity chromatography step, having immunoreactivity but containing no enzyme activity. Immunoblot analysis revealed that the antibodies obtained after the subtractive affinity chromatography purification reacted primarily with one protein band corresponding to esterase type III, at around 68 KDa, and some other minor protein bands when large amounts of the crude extracts were used. Using the purified antibodies, an indirect ELISA for the quantification of esterase type III was established. A good correlation (r = 0.8P =0.04) was found between the ELISA data of esterase III amount and the enzyme activities in the crude extracts. The increased activities of fungal esterase with the prolonged incubation from 5 to 35 days were found to be due to an increase in esterase production. High temperature (25°C) was preferred for the enzyme production and enhanced esterase activity.

ISSN:0954-0105    

DOI:10.1080/09540109609354902

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In the food, particularly the feed, industry, large quantities of soya bean protein products are used for the formulation of end‐products destined for human or animal consumption. These basic ingredients and the final end products often have to fulfill specific requirements regarding the presence of antinutritional compounds (ANCs) and their allergenic potential. Therefore, a special need exists for the identification and characterization of ANCs and the causative factors behind allergy and hyper sensitivity. This paper describes the results of a comparative study of a previously identified unknown antigenic soya bean P22–25 protein with the first, recently describedGly mI (or P34) soya bean allergen. Sodium dodecyl sulphate polyacrylamide gel electrophoresis and Western blotting analysis were carried out using calf anti‐soya protein sera and a murine anti‐Gly mI (or P34) monoclonal antibody in order to detect the antigenic soya bean P22–25 protein and the allergenGly m(or P34) respectively. The results showed that these proteins were different. In addition, a number of industrial soya bean products were analyzed for the presence of both apparent antigenicity (essentially ß‐conglycinin and P22–25) using calf anti‐soya protein sera and the allergenGly mI (or P34), and both ß‐conglycinin, P22–25 and P34 could be detected to a varying extent in the products analyzed.

ISSN:0954-0105    

DOI:10.1080/09540109609354903

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The effect of bovine milk casein digests on the ability of thioglycollate‐elicited mouse peritoneal macrophages to produce nitrite and to ingest latex beads was investigated. Intactαs1‐casein and κ‐casein significantly inhibited nitrite production by the macrophages. The inhibitory activity of the latter was little influenced by trypsin or chymotrypsin digestion, while that of the former decreased with increasing proteinase digestion time. In contrast, pepsin digestion changed the inhibitory activity of a s1‐casein and κ‐casein into an enhancing activity. Intact ß‐casein, however, had an enhancing effect on nitrite production, and its activity increased noticeably when the protein was digested with pepsin. The enhancing activity of pepsin digests of each casein component reduced when the digest was treated with carboxypeptidase A. Moreover, a trypsin or chymotrypsin digest of α s1‐casein and κ‐casein inhibited ingestion of latex beads by the macrophages, while a pepsin digest of each casein component enhanced it. These results suggest that the neonate ingestion of infant formula made with bovine milk might reduce resistance to infection via suppression of macrophage functions, such as antimicrobial nitrogen intermediate production and phagocytosis in their gut mucosa, since it is known that gastric secretion and pepsin activity are weak in neonates and the major portion of the caseins ingested by neonates leaves the stomach after minimal digestion.

ISSN:0954-0105    

DOI:10.1080/09540109609354904

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0954-0105    

DOI:10.1080/09540109609354897

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor