The Development of a Quantitative ELISA for Aflatoxin B1 in Ground Peanuts Using Antibodies Isolated From the Yolk of a Laying Hen

Flagellin from Listeria monocytogenes is glycosylated with beta-O-linked N-acetylglucosamine

Glycan staining of purified flagellin from Listeria monocytogenes serotypes 1/2a, 1/2b, 1/2c, and 4b suggested that the flagellin protein from this organism is glycosylated. Mass spectrometry analysis demonstrated that the flagellin protein of L. monocytogenes is posttranslationally modified with O-linked N-acetylglucosamine (GlcNAc) at up to six sites/monomer. The sites of glycosylation are all located in the central, surface-exposed region of the protein monomer. Immunoblotting with a monoclonal antibody specific for beta-O-linked GlcNAc confirmed that the linkage was in the beta configuration, this residue being a posttranslational modification commonly observed in eukaryote nuclear and cytoplasmic proteins.

Aflatoxin B1and its interconverting metabolite aflatoxicol in milk: the situation in Mexico

Between 1996 and 1998, 580 litres of milk in Mexico were surveyed for aflatoxin B(1) (AFB(1)) and its metabolite aflatoxicol (AFL), which are mutagenic and carcinogenic mycotoxins that interconvert AFB(1)-AFL-AFB(1). The seven most consumed brands from different regions of Mexico included pasteurized and ultrapasteurized milk with four different fat levels: whole fat (28-33 g l(-1)), half-skimmed (10-20 g l(-1)), light (1-4 g l(-1)) and with vegetable oil (33 g l(-1)). Aflatoxins in each sample were concentrated with total aflatoxin immunoaffinity columns and quantitated by high-performance liquid chromatography. A milk sample was considered contaminated if it contained >/=0.05 microg l(-1) AFL. Pasteurization and ultrapasteurization of milk did not control contamination with AFL, which was present in 13% of samples at >/=0.05 microg l(-1) and in 8% at >/=0.5 microg l(-1), with a range of AFL from 0 to 12.4 microg l(-1). AFB(1) was present mainly in traces (0-0.4 microg l(-1)). The safest milk in relation to AFL contamination was imported milk powder with vegetable oil. There was a significant correlation between contamination of milk with AFL and the autumn (p<0.0002); the fat content was not significant.

Development of enzyme-immunoassays based on egg yolk antibodies for the detection of mycotoxins

Enzyme-linked immunosorbent assays (ELISA) proved to be a fast and simple method for the detection of mycotoxins and other undesired contaminants in food and feed. The present study is focused on the optimisation and exploitation of the egg yolk antibody technology in order to develop competitive ELISAs for the detection of mycotoxins in cereals. Due to its importance as one of the most relevant Fusarium mycotoxins, the trichothecene deoxynivalenol (DON) was selected as representative. Chickens were immunised with different protein conjugates performing varying booster intervals. The antibodies were isolated by the poly(ethylene glycol) precipitation method according to Polson. By use of these antibodies an indirect competitive ELISA was developed for the detection of DON. First investigations of naturally contaminated wheat samples showed a good correspondence with results obtained by GC-ECD when calibration in blank wheat extracts was performed.

Passive protection of specific pathogen free chicks against infectious bursal disease by in-ovo injection of semi-purified egg-yolk antiviral immunoglobulins

In order to develop an experimental model for passive immunity in SPF chickens, active neutralizing immunoglobulins (Ig) directed against infectious bursal disease virus (IBDV) were extracted from the yolk of eggs laid by conventional layers immunized against IBDV. Concentrated Ig extracts were inoculated via the intra-vitellin route into 7-day-old embryonated SPF hen eggs. Although detrimental to hatchability, Ig inoculation resulted in hatching two series of SPF chicks with passive immunity against IBDV. The neutralizing and ELISA antibody titres at 1 day-old (respectively 12.64 and 13.15 log2; and 4915 and 4277), the kinetics of decay of the anti-IBDV antibodies and the protection afforded by passive antibodies against highly virulent IBDV challenge proved highly consistent with data previously reported on conventional chicks. In-ovo inoculation of purified egg-yolk immunoglobulins may hence be a good experimental model for anti-IBDV maternally-transmitted immunity. This experimental model might possibly be adapted to other pathogens or vaccines for which interference with maternally derived antibodies is a matter of concern at 1 day-old.