摘要:

The mechanism for the hypo‐responsiveness of mammary gland mononuclear cells (MGMCs) to mitogen stimulation is poorly understood. It has been hypothesized that hypo‐responsiveness of MGMCs may be due to interference by lactoferrin or other whey proteins present in mammary secretions with lymphocyte proliferation stimulated by interleukin‐2 (IL‐2). To address this hypothesis, an experiment was designed to evaluate proliferation of an IL‐2‐dependent bovine cytotoxic T‐lymphocyte cell line (BT‐2) in the presence of apo‐ and iron‐saturated lactoferrin (APOLF and FELF) and transferrin (APOTF and FETF), immunoglobulin G (IgG) and serum albumin (SA) at concentrations ranging from 0.02 to 2.5 mg ml‐1. The lowest concentration of APOLF and FELF increased BT‐2 cell proliferation. Conversely, increasing concentrations of LF significantly inhibited BT‐2 cell proliferation. Only the highest concentrations of APOTF, FETF and IgG negatively influenced BT‐2 cell proliferation. Serum albumin had no effect. These data suggest that LF has a dose‐dependent bimodal influence on a bovine IL‐2‐dependent cytotoxic T‐lymphocyte cell line, and high concentrations of LF and other mammary secretion whey proteins may be associated with MGMC hypo‐responsiveness during the non‐lactating period, possibly through interference with IL‐2‐stimulated lymphocyte proliferation.

ISSN:0954-0105    

DOI:10.1080/09540109309354791

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An improved immunoassay for chlorpyrifos‐methyl (Reldan) in grain has been developed, based on an immobilized polyclonal antibody. This assay had greater sensitivity (limit of detection of 0.02 ppm in grain, or 0.05–0.1 ppb in buffer), was less susceptible to interference from methanol (used to extract residue from the grain) and was of greater precision than the earlier monoclonal antibody assay (Skerrittet al.,1992b). The polyclonal antibody exhibited greater cross‐reaction with chlorpyrifos‐ethyl (not used as a grain protectant), but less with fenchlorphos and bromophos (used occasionally as grain protectants), and employed a more stable peroxidase conjugate than the monoclonal antibody assay. Good correlations were obtained between chlorpyrifos‐methyl residue levels in wheat grain determined by the improved immunoassay and by gas chromatogra‐phy. The properties of the polyclonal antibody should also allow its use in a rapid field assay.

ISSN:0954-0105    

DOI:10.1080/09540109309354792

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Polyclonal antibodies against an aldrin/dieldrin immunogen have been raised in rabbits and used as the basis of an enzyme‐linked immunosorbent assay (ELISA). This assay can detect dieldrin in milk in the range 5 μg ml‐1to Ing ml‐1reliably. This range differs in skimmed and semi‐skimmed milk, and in cream, reflecting the differences in fat content between these samples.

ISSN:0954-0105    

DOI:10.1080/09540109309354793

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Polyclonal antibodies against the 40 kDa sterigmatocystin O‐methyltransferase (ST‐OMT) were produced after immunizing rabbits with the purified enzyme. Immunoblot analysis of the crude enzyme preparation fromAspergillus parasiticusstrain 163 revealed one band corresponding to ST‐OMT (∼40 kDa) as well as several other protein bands without enzymatic activity. The antiserum was further purified by passing the ammonium sulfate precipitation‐cut IgG through a column that was armed with proteins isolated from DEAE‐Sephadex gel filtration fraction with immunoreactivity but containing no enzyme activity. Immunoblot analysis revealed that the purified antibodies, after the subtractive affinity chromatography, reacted primarily with one major (∼ 40 kDa) and two minor protein bands of 40–46 kDa size proteins when large amounts of the crude extracts were used. At low protein concentration, only one immunoreactive band of 40 kDa was observed for the crude enzyme preparation. Using the purified antiserum, an indirect ELISA was established for the enzyme detection. Analysis of various fungal extracts showed that the purified antiserum was highly specific for the enzyme. The purified antiserum has also been used successfully for screening the cDNA library in cloning the gene for the enzyme and in monitoring the enzyme produced inEscherichia coliin which this gene(omt‐1)was expressed.

ISSN:0954-0105    

DOI:10.1080/09540109309354794

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A species‐specific ELISA has been developed for quantitatively detecting the presence of the granary weevilSitophilus granariusin grain. The assay is based on the use of monoclonal antibodies (MAb) and polyclonal antibodies (PAb) directed against a 59 500 Da protein fromS. granarius.This protein, tentatively termed the W protein, has an isoelectric point of 6–0. Two MAb to the W protein were obtained that exhibited clear specificity and did not react by ELISA with closely related species. Both MAb and PAb against the Wprotein were used to develop a specific sandwich ELISA immunoassay to estimate the proportion ofS. granariusin an infesting insect population in wheat. The assay reported here also lays a foundation for the further development of MAb‐based ELISA techniques for detecting specific insect species in contaminated grain.

ISSN:0954-0105    

DOI:10.1080/09540109309354795

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A detailed toxicity analysis was performed on the top minnow utilizing the stick‐enzyme immunoassay (S‐EIA), the mouse bioassay, the guinea pig atrium assay and fluorometric HPLC. The S‐EIA test indicated 96% of the samples tested contained polyether toxins. Mice injected with acetone extractions from top minnow displayed symptoms of toxicity while the guinea pig atrium assay demonstrated the presence of a polar, Na+channel inhibitor.

ISSN:0954-0105    

DOI:10.1080/09540109309354796

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0954-0105    

DOI:10.1080/09540109309354790

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor