Application of deadenylase electrochemiluminescence assay for ricin to foods in a plate format.

A recently developed bead-based deadenylase electrochemiluminescence assay for ricin is simple and sensitive in its ability to detect ricin, based on the catalytic activity of the toxin subunit, ricin A chain. The assay was modified to work in a 96-well plate format and evaluated by using juice samples. The plate-based assay, unlike the bead-based assay, includes wash steps that enable the removal of food particles.

Identification of the RNA N-glycosidase activity of ricin in castor bean extracts by an electrochemiluminescence-based assay.

A simple electrochemiluminescence-based assay for RNA N-glycosidase activity has been modified to permit its use with authentic extracts of Ricinus communis (castor beans) and Abrus precatorius (jequirity seeds)--the natural sources of ricin and abrin. Modifications include the addition of an RNase inactivator to the reaction mixture, elimination of a signal-enhancing monoclonal antibody, and optimization of the incubation temperature. Concurrent testing with two substrates provides a diagnostic tool enabling castor bean toxins to be differentiated from a larger selection of N-glycosidase toxins than was previously examined.

An activity-dependent assay for ricin and related RNA N-glycosidases based on electrochemiluminescence.

Synthetic biotinylated RNA substrates were cleaved by the combined actions of ricin holotoxin and a chemical agent, N,N'-dimethylethylenediamine. The annealing of the product with a ruthenylated oligodeoxynucleotide resulted in the capture of ruthenium chelate onto magnetic beads, enabling the electrochemiluminescence (ECL)-based detection of RNA N-glycosidase activities of toxins. ECL immunoassays and the activity assay exhibited similar limits of detection just below signals with 0.

Rapid detection of Clostridium botulinum toxins A, B, E, and F in clinical samples, selected food matrices, and buffer using paramagnetic bead-based electrochemiluminescence detection.

Sensitive and specific electrochemiluminescence (ECL) assays were used to detect Clostridium botulinum neurotoxins serotypes A, B, E, and F in undiluted human serum, undiluted human urine, assay buffer, and selected food matrices (whole milk, apple juice, ground beef, pastry, and raw eggs). These novel assays used paramagnetic bead-based electrochemiluminescent technology in which biotinylated serotype-specific antibodies were bound to streptavidin-coated paramagnetic beads. The beads acted as the solid support and captured analyte from solution.

Activity-dependent fluorescent labeling of bacterial cells expressing the TOL pathway.

3-Ethynylbenzoate (3EB) functions as a novel, activity-dependent, fluorogenic, and chromogenic probe for bacterial strains expressing the TOL pathway, which degrade toluene via conversion to benzoate, followed by meta ring fission of the intermediate catechol. This direct physiological analysis allows the fluorescent labeling of cells whose toluene-degrading enzymes have been induced by an aromatic substrate.

Use of 3-hydroxyphenylacetylene for activity-dependent, fluorescent labeling of bacteria that degrade toluene via 3-methylcatechol.

3-hydroxyphenylacetylene (3-HPA) served as a novel, activity-dependent, fluorogenic and chromogenic probe for bacterial enzymes known to degrade toluene via meta ring fission of the intermediate, 3-methylcatechol. By this direct physiological analysis, cells grown with an aromatic substrate to induce the synthesis of toluene-degrading enzymes were fluorescently labeled.