ABSTRACT
It is well established the beneficial role of silicon (Si) in alleviating abiotic stress. However, it remains poorly understood the mechanisms of the Si-mediated protection against metal deficiency, especially the zinc (Zn) one. Recently, it has been proposed that Si may act by an interaction with this biometal in the root apoplast contributing to its movement through the plant, as in the case of Fe deficiency. In the present work, the effect of initial or continuous Si doses in soybean Zn deficient plants has been studied. For that purpose, plants grown in hydroponic culture were treated with different Si doses (0.0, 0.5 and 1.0 mM) under Zn limiting conditions. SPAD index in leaves, several growth parameters, mineral content in the whole plant and the formation of Zn pools in roots were determined. An initial addition of 0.5 mM of Si to the nutrient solution led to an enhancement of plants growth, Zn and Si content in leaves, and a higher storage of Zn in the root apoplast. The results suggest that this treatment enhanced Zn accumulation on roots and its movement to shoots when needed, mitigating Zn deficiency symptoms.
Subject(s)
Glycine max/drug effects , Silicon/pharmacology , Zinc/deficiency , Dose-Response Relationship, Drug , Plant Leaves/drug effects , Plant Leaves/metabolism , Plant Roots/drug effects , Plant Roots/metabolism , Silicon/administration & dosage , Silicon/pharmacokinetics , Glycine max/metabolism , Tissue Distribution , Zinc/pharmacokineticsABSTRACT
En algunos pacientes con dermatitis atópica se ha demostrado que la aplicación directa de aeroalergenos sobre la piel es capaz de reproducir las lesiones características de la enfermedad. Por ello, si las pruebas epicutáneas fueran una técnica bien estandarizada, podrían constituir el modelo ideal de estudio alergológico en estos pacientes. El objetivo de este estudio fue determinar la concentración óptima para pruebas epicutáneas con varios aeroalergenos. Material y métodos: Se seleccionaron 137 pacientes con dermatitis atópica y 32 controles atópicos > 12 años en los 10 centros participantes en el estudio. Se realizaron pruebas del prick y pruebas epicutáneas con extractos de D. pteronyssinus, P. pratense, O. europaea, Alternaria alternata y epitelio de gato en concentraciones de 10, 5 y 1 HEP (Laboratorios DIATER®) y se determinó la IgE específica en el suero frente a aquellos alergenos positivos en el prick. Resultados: Los grupos de pacientes y controles fueron homogéneos. Obtuvimos un 25,7% y 9% de parches positivos con 10 HEP de D. pteronyssinus en pacientes y controles, respectivamente. Con O. europaea sólo hubo un 3% de pacientes y controles con un parche positivo. Con el resto de los alergenos la frecuencia de parches positivos en los pacientes fue del 11,2%, 8,8% y 7,5% frente a P. pratense, A. alternata y gato, respectivamente, y del 3% en los controles. Conclusión: La concentración más alta utilizada de 10 HEP con D. pteronyssinus puede considerarse adecuada para las pruebas epicutáneas. Respecto a los otros alergenos, esta concentración parece encontrarse por debajo de la óptima, sobre todo en el caso de O. europaea
In some patients with atopic dermatitis, characteristic eczematous skin lesions can be induced by patch testing with aeroallergens. However, atopy patch test is not well standardised. The aim of this study was to stablish the optimal concentration of aeroallergens for patch testing. Material and methods: We selected 137 patients with atopic dermatitis and 32 atopic controls in the 10 participant centres. Prick test and atopy patch test with D. pteronyssinus, P. pratense, O. europaea, A. alternata and cat dander extracts at 10, 5 and 1 HEP (DIATER S.A.) as well as specific IgE determination were performed. Results: The groups of patients and controls were homogeneous. A 25,7% and 9% of patients and controls, respectively, had a positive result when patch testing with D. pteronyssinus extract at 10 HEP. Only a 3% of positive patch tests were obtained with O. europaea in patients and controls. The frequency of positive patch tests with the other allergens in patients was 11,2%, 8,8% y 7,5% for P. pratense, A. alternata and cat dander, respectively, and 3% in controls. Conclusions: The highest concentration of 10 HEP could be considered optimal for the atopy patch test with D. pteronyssinus. Such concentration seems to be lower than the optimal one when patch testing the other allergens
