Search results for "Hapten"
showing 10 items of 92 documents
Development of competitive enzyme-linked immunosorbent assays for boscalid determination in fruit juices
2012
Abstract Boscalid is a modern, broad-spectrum carboxamide pesticide highly efficient against most fungal diseases affecting valuable crops. In this study, a boscalid-mimicking derivative with a six-carbon spacer arm replacing the chlorine atom at the pyridine ring of the target molecule was synthesized and coupled to carrier proteins. Following rabbit immunization, antibodies against this agrochemical were obtained for the first time, and they were characterised in terms of affinity and specificity, tolerance to solvents, and robustness to changes in buffer pH and ionic strength, using two assay formats. Both of the optimised immunoassays showed limits of detection below 0.1 μg/L. Moreover,…
The use of metallocenic esters of n-hydroxysuccinimide for metallohapten synthesis
1991
Different organometallic markers have been described in a new technique for the labelling of many drugs. Thus metallocenic esters of [M = (;CO)3CrC6H5; (;CO)3CrC6H5(;CH2)3; η-C5H5FeC5H4; (;CO)3MnηC5H4; (;CO)3MnηC5H4COCH2CH2; ηC5H4(;ηC5H5)Co+PF−6] react with primary or secondary amine drugs [DRUGNHR] for a psychostimulant drug: amphetamine; tricyclic antidepressants—desipramine and nortriptyline; a vasodilator—histamine; an adrenergic substance—norfenefrine; and for a central stimulant—meth-amphetamine, to give the metallohaptens MCON(;R)—DRUG. All these compounds have been fully characterized by different analytical methods and have potentialities for biological assays. This synthetic route…
Hemocyanin from the keyhole limpetMegathura crenulata(KLH) carries a novel type of N-glycans with Gal(β1-6)Man-motifs
2002
Keyhole limpet (Megathura crenulata) hemocyanin (KLH), an extracellular respiratory protein, is widely used as hapten carrier and immune stimulant. Although it is generally accepted that the sugar constituents of this glycoprotein are likely to be implicated in the antigenicity and biomedical properties of KLH, knowledge of its carbohydrate structure is still limited. Therefore, we have investigated the N-linked oligosaccharides of KLH. Glycan chains were enzymatically liberated from tryptic glycopeptides, pyridylaminated and separated by two-dimensional HPLC. Only neutral oligosaccharides were obtained and characterized by carbohydrate constituent and methylation analyses, MALDI-TOF-MS, ES…
Desarrollo de métodos inmunoquímicos para el análisis en alimentos de fungicidas inhibidores de la succinato deshidrogenasa
2017
El uso de plaguicidas constituye una forma eficaz y hoy por hoy necesaria para combatir gran parte de las plagas que afectan a los cultivos agrícolas. Sin embargo, su uso puede dar lugar a la aparición de residuos en los alimentos que llegan al consumidor, lo que puede derivar en un problema de seguridad alimentaria. Por ello, es necesario el desarrollo de métodos analíticos altamente sensibles y selectivos para la monitorización de dichos residuos, que permitan la detección de concentraciones lo más bajas posibles. En este contexto, en esta Tesis Doctoral se ha abordado el desarrollo de métodos inmunoquímicos de elevada sensibilidad y selectividad para el análisis en muestras de alimentos …
Estrategias alternativas para la bioconjugación de ocratoxina A y su aplicación en inmunodiagnóstico alimentario
2020
Ocratoxina A (OTA) es un metabolito secundario producido por hongos del género Aspergillus y Penicillium. Esta micotoxina puede encontrarse en una gran variedad de alimentos, entre los que se encuentran cereales, café o vino. OTA es un potente carcinógeno en roedores, motivo por el que se encuentra clasificado en el grupo 2B (posible carcinógeno para humanos) por la Agencia Internacional de Investigación sobre el Cáncer. Con el objetivo de reducir la exposición de los consumidores a esta micotoxina, la Comisión Europea ha establecido concentraciones máximas en varias matrices alimentarias, siendo este límite de 2 µg/L en el caso de vino y zumo de uva. Entre las diferentes técnicas analítica…
Hapten Design and Antibody Generation for Immunoanalysis of Spirotetramat and Spirotetramat-enol
2018
Spirotetramat - a tetramic acid insecticide - is rapidly metabolized or degraded to give spirotetramat-enol; so, common residue definitions include the sum of both compounds. In the present study, two spirotetramat-functionalized derivatives (haptens) have been designed to generate immunoreagents to these molecules for rapid immunochemical analysis. Haptens have been synthesized with alternative linker tethering sites and, for the first time, high-affinity antibodies have been generated with different specificities to these active principles. Two sensitive assays have been developed using the same antibody in different formats, and by using linker-site heterologous haptens, the selectivity …
Rationally designed haptens for highly sensitive monoclonal antibody-based immunoanalysis of fenhexamid.
2018
Immunochemical methods have been consolidated during the last few years as complementary analytical strategies for chemical contaminant and residue determination. However, generation of suitable immunoreagents for small organic molecules demands adequate hapten design. In this study, fenhexamid was considered as a model compound and novel haptens were designed and synthesized in order to evaluate the influence of the linker tethering site on antibody binding properties and immunoassay parameters. Haptens were conceived with the spacer arm at different positions, while the more antigenic aromatic moiety was kept free. The synthesis of these functionalized compounds was accomplished by total …
Generation of anti-azoxystrobin monoclonal antibodies from regioisomeric haptens functionalized at selected sites and development of indirect competi…
2012
Azoxystrobin is a modern strobilurin fungicide used around the world to combat prime diseases affecting highly valuable crops. Accordingly, residues of this chemical are frequently found in food, even though mostly under maximum tolerated levels. We herein describe the development of an indirect competitive immunoassay for the determination of azoxystrobin residues. A panel of monoclonal antibodies displaying subnanomolar affinity to azoxystrobin was generated using, as immunizing haptens in mice, four functionalized derivatives carrying the same spacer arm located at different rationally chosen positions. This collection of antibodies was thoroughly characterized with homologous and hetero…
Evaluation of the concept of heterology in a monoclonal antibody-based ELISA utilizing direct hapten linkage to polystyrene microtiter plates.
2005
A series of new heterologous haptens has been synthesized and used as coating haptens in an antigen-immobilized immunoassay with a monoclonal antibody against atrazine. Coating was achieved by covalently linking the different haptens to a glutaraldehyde network directly bound to the polystyrene surface of a standard 96-well microtiter plate. With the assay designed in the antigen-immobilized format with direct chemical linkage of the hapten to the solid polystyrene surface well-defined hapten densities were achieved in all experiments. The results of different experiments with different coating haptens were comparable. Using different heterologous haptens it appears that the concept of hete…
Synthesis of azoxystrobin transformation products and selection of monoclonal antibodies for immunoassay development
2012
The use of agrochemicals for crop protection may result in the presence of toxic residues in soils and aquatic environments, besides in foodstuffs. Most often just the parent compound is included in the definition of pesticide residue, even though chemicals resulting from biotransformation and degradation routes might also be of toxicological relevance. Azoxystrobin is a broad-spectrum systemic fungicide widely used worldwide to combat pathogenic fungi affecting plants. We herein report the synthesis and detailed chemical characterization of several of the most relevant metabolites and degradates of azoxystrobin. These compounds were further employed as ligands for screening a collection of…