Diversificación de especies ornamentales en un grupo de pequeños productores florícolas de la colectividad japonesa de Florencio Varela, Buenos Aires, Argentina

La actividad florícola en el área periurbana del Partido de Florencio Varela se caracteriza por fuertes procesos de reestructuración, ocurridos en las últimas décadas, impulsados por innovaciones tecnológicas (i.e., producción bajo cubierta, riego por goteo, utilización de agroquímicos) y comerciales (i.e., consolidación de la Gran distribución en los canales minoristas). Estos procesos inducen en forma ascendente el desarrollo de explotaciones comerciales de mayor escala, capitalizadas y una creciente heterogeneización del sector agropecuario. Sin embargo, la introducción de nuevas especies y variedades en la producción florícola se encuentra restringida debido al exiguo conocimiento, por parte de los actores sociales, de las técnicas de producción y al escaso acceso al material vegetal, herramienta fundamental para la innovación tecnológica. A partir de allí surgió la necesidad de generar un equipo interinstitucional de técnicos extensionistas de la Facultad de Ciencias Agrarias - UNLZ y del Instituto Fitotécnico de Santa Catalina de la Facultad de Ciencias Agrarias y Forestales - UNLP, para el abordaje de la problemática presente en un grupo de productores florícolas, pertenecientes a la colectividad japonesa de Florencio Varela y que han logrado constituir una Cooperativa de trabajo Ecoflor Ltda., referente a nivel local. A través de reuniones grupales, de talleres y jornadas de capacitación en producción florícola se seleccionaron de manera conjunta con los productores y los técnicos extensionistas, las especies ornamentales a propagar, basándose en las necesidades del mercado, de los consumidores y de las preferencias de los floricultores.Facultad de Ciencias Agrarias y Forestale

Effects of Intracellular Calcium and Actin Cytoskeleton on TCR Mobility Measured by Fluorescence Recovery

Background: The activation of T lymphocytes by specific antigen is accompanied by the formation of a specialized signaling region termed the immunological synapse, characterized by the clustering and segregation of surface molecules and, in particular, by T cell receptor (TCR) clustering. Methodology/Principal Findings: To better understand TCR motion during cellular activation, we used confocal microscopy and photo-bleaching recovery techniques to investigate the lateral mobility of TCR on the surface of human T lymphocytes under various pharmacological treatments. Using drugs that cause an increase in intracellular calcium, we observed a decrease in TCR mobility that was dependent on a functional actin cytoskeleton. In parallel experiments measurement of filamentous actin by FACS analysis showed that raising intracellular calcium also causes increased polymerization of the actin cytoskeleton. These in vitro results were analyzed using a mathematical model that revealed effective binding parameters between TCR and the actin cytoskeleton. Conclusion/Significance: We propose, based on our results, that increase in intracellular calcium levels leads to actin polymerization and increases TCR/cytoskeleton interactions that reduce the overall mobility of the TCR. In a physiological setting, this may contribute to TCR re-positioning at the immunological synapse

Systems Imaging of the Immune Synapse

Three-dimensional live cell imaging of the interaction of T cells with antigen presenting cells (APC) visualizes the subcellular distributions of signaling intermediates during T cell activation at thousands of resolved positions within a cell. These information-rich maps of local protein concentrations are a valuable resource in understanding T cell signaling. Here, we describe a protocol for the efficient acquisition of such imaging data and their computational processing to create four-dimensional maps of local concentrations. This protocol allows quantitative analysis of T cell signaling as it occurs inside live cells with resolution in time and space across thousands of cells

Dynamics of Membrane Trafficking Downstream of B and T Cell Receptor Engagement: Impact on Immune Synapses

The onset of an adaptive immune response requires the activation of T and B lymphocytes by antigen-presenting cells, through a specialized form of intercellular communication, known as the immunological synapse (IS). In B lymphocytes the IS promotes efficient recognition and acquisition of membrane-bound Ags, while in T cells, it modulates the T cell response upon exposure to peptide-major histocompatibility complexes. In this review, we highlight the similarities that determine B and T cell activation, focusing on immune receptor downstream signaling events that lead to synapse formation. We stress the notion that polarization of T and B lymphocytes characterized by global changes in cytoskeleton and membrane trafficking modulates synapse structure and function, thus determining lymphocyte effector functions and fate

Impact of ultrasound examination shortly after kidney transplantation

Background Ultrasound is routinely performed at our transplant unit within the first 48h of kidney transplantation (KTX). The objective of this study was to evaluate the association of ultrasound results and, in particular, elevated resistance indices (RIs) with the occurrence of surgical complications and allograft outcomes. Methods The study included all kidney allograft recipients undergoing transplantation at our center between January 2010 and December 2011 (N = 329). Ultrasound examination was performed on 315 recipients (95.7%). Results Delayed graft function was more common in subjects with a high RI (0.7) than in patients with an RI < 0.7 (47.2 vs. 28.2%; p = 0.032). A lack of arterial signal was detected in eight patients (2.5%), of whom five had a vascular complication that required surgical therapy. In 12 patients (3.8%), RI was 1 without any other signs of vascular impairment. Even though such values can be a sign of venous thrombosis, no case was observed in any of these patients. Conclusions The results of our study suggest that ultrasound evaluation of the transplanted kidney shortly after transplantation is a valuable tool not only for detecting vascular complications but also as a predictor of graft outcome regarding delayed graft function.(VLID)354420