Date: 2014/08/18

Venue: Room E131, 1st Floor, Building E, School of Science

Time: 14:00 - 15:30

Speaker: Prof. Alex Costa (Department of Biosciences, University of Milan, Italy)

Title: Molecular and Technical advances for in vivo analysis of Ca2+ dynamics in plant cells

Abstract:
In plants, rises in cytosolic Ca2+ concentration ([Ca2+]cyt) occur in response to both biotic and abiotic stimuli. These rises can, depending on the stimulus, display the form of a single transient or repetitive Ca2+ oscillations and are commonly designated as "Ca2+ signatures". Generation and shaping of [Ca2+]cyt signatures depends on fine-tuning of Ca2+ influxes and effluxes occurring at both the plasma membrane (PM) and membranes of the different subcellular compartments. The opening of Ca2+-permeable influx channels in response to a stimulus will release Ca2+ into the cytosol and cause the generation of a Ca2+ spike, while activity of Ca2+ efflux transporters (H+-Ca2+ antiporters and Ca2+-ATPases) will return the [Ca2+]cyt to resting concentrations. In order to understand how the cytosolic Ca2+ dynamics are generated and shaped in different cell types, two issues need to be addressed: i) the study of how do organelles participate in these processes and ii) the possibility to perform single cell Ca2+ analyses in complex tissues and organs, in natural context and in closer physiological conditions. The first part of the seminar will be dedicated to show in the planta use of the genetically encoded FRET (Förster Resonance Energy Transfer)-based Ca2+ Chameleon sensor. Particular attention will be given to the development of Chameleon probes for the analyses of Ca2+ dynamics in several subcellular compartments such as: cytosol, nucleus, mitochondria, peroxisomes and endoplasmic reticulum. In the second part of the seminar the development of a new microscopy solution, based on Selective Plane Illumination Microscopy (SPIM), for FRET-based Ca2+ imaging analyses in Arabidopsis root cells will be presented.

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