RESUMEN
A method of the competitive immunochromatographic assay of the pesticides 2,4-D (2,4-dichlorophenoxyacetic acid) and simazine (2-chloro-4,6-bis(N-ethylamino)-1,2,5-triazine) in aqueous samples was developed. Monoclonal antibodies to these pesticides labeled with colloidal gold were used to visualize the results. The sensitivity of the 2,4-D and simazine assay is 12 ng/ml, and the time of analysis is 3-7 min. The method does not differ in sensitivity from the competitive EIA using conjugates of monoclonal antibodies to the pesticides with horseradish peroxidase; however, the time of the EIA is 1.5 h. The immunochromatographic method of the pesticide detection is available and simple and may be recommended for the development of assays of any other low-molecular compounds. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 2; see also http://www.maik.ru.
Asunto(s)
Ácido 2,4-Diclorofenoxiacético/análisis , Anticuerpos Monoclonales/inmunología , Cromatografía/métodos , Oro Coloide/química , Simazina/análisis , Ácido 2,4-Diclorofenoxiacético/inmunología , Técnicas para Inmunoenzimas , Sensibilidad y Especificidad , Simazina/inmunologíaRESUMEN
A biosensor system based on total internal reflectance fluorescence (TIRF) was used to discriminate a mixture of the triazines atrazine and simazine. Only cross-reactive antibodies were available for these two analytes. The biosensor is fully automated and can be regenerated allowing several hundreds of measurements without any user input. Even a remote control for online monitoring in the field is possible. The multivariate calibration of the sensor signal was performed using artificial neural networks, as the relationship between the sensor signals and the concentration of the analytes is highly non-linear. For the development of a multi-analyte immunoassay consisting of two polyclonal antibodies with cross-reactivity to atrazine and simazine and different derivatives immobilised on the transducer surface, the binding characteristics between these substances like binding capacity and cross-reactivity were characterised. The examination of three different measurement procedures showed that a two-step measurement using only one antibody per step allows a quantification of both analytes in a mixture with limits of detection of 0.2 microg/l for atrazine and 0.3 microg/l for simazine. The biosensor is suitable for online monitoring in the field and remote control is possible.
Asunto(s)
Algoritmos , Anticuerpos/química , Atrazina/análisis , Atrazina/química , Técnicas Biosensibles/instrumentación , Fluoroinmunoensayo/instrumentación , Redes Neurales de la Computación , Simazina/análisis , Simazina/química , Anticuerpos/inmunología , Atrazina/inmunología , Técnicas Biosensibles/métodos , Calibración , Mezclas Complejas/análisis , Mezclas Complejas/química , Diseño de Equipo , Análisis de Falla de Equipo/métodos , Estudios de Factibilidad , Fluoroinmunoensayo/métodos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Simazina/inmunología , Triazinas/análisis , Triazinas/química , Triazinas/inmunologíaRESUMEN
Detecting labels based on water dispersions of colloidal textile dyes were developed that are useful in various analytical and diagnostic test systems for a simple visual assessment of the assay. Colored water-insoluble particles of dyes were used for the sorptional immobilization of streptavidin on their surface. The resulting streptavidin-dye (STR-DYE) complexes possessed a high visualizing capacity and were used for the combined detection of pesticides (simazine and 2,4-dichlorophenoxyacetic acid) by noninstrumental immunoassay (DYE-comb-assay, competitive dot-immunoassay in the comb format). The detection limits and the duration of our DYE-comb-assay (4 ng/ml, 20-25 min), HRP-comb-assay (competitive dot-immunoassay in the comb format using the enzymic conjugate of STR with horseradish peroxidase) (16 ng/ml), and the traditional competitive ELISA (12-16 ng/ml, 1.5 h) were compared. This DYE-comb-assay is simple enough and can be used under field conditions.
Asunto(s)
Ácido 2,4-Diclorofenoxiacético/análisis , Coloides , Inmunoensayo/métodos , Simazina/análisis , Ácido 2,4-Diclorofenoxiacético/inmunología , Sensibilidad y Especificidad , Simazina/inmunologíaAsunto(s)
Anticuerpos Monoclonales , Complejo Antígeno-Anticuerpo/análisis , Reacciones Antígeno-Anticuerpo , Ácido 2,4-Diclorofenoxiacético/inmunología , Técnicas Biosensibles , Peroxidasa de Rábano Silvestre/inmunología , Cinética , Mediciones Luminiscentes , Fotometría/instrumentación , Fotometría/métodos , Simazina/inmunologíaRESUMEN
Evaluated was the effect produced by some heavy metals and pesticides on the antigenic behaviour of Staphylococcus aureus strains isolated from cows and sheep with mastitis. The experiments were carried out with 9 strains, their antigenic structure being determined with the use of 16 factor sera prior to and after being gradually acted upon with lead acetate, copper sulfate, zinc sulfate, cadmium, and herbazin-50. It was found that under the effect of these chemical factors the capsule-resembling layer grew. In connection with this the staphylococci grew within the nutrient media, forming mucoid colonies. The serologic analysis revealed lower agglutinin ability due to the release of deeply set antigens. The growth of the capsular layer was associated with the increase in the virulence of staphylococci, which was established in the conditions of the practice on a dairy farm adjacent to a Copper producing Works.