Thu. 1 Oct, 2009 15:00 - 16:00
Prof. Conrad Mullineaux, School of Biological and Chemical Sciences, Queen Mary, University of London, UK.
Title: Intercellular communication in filamentous cyanobacteria
Filamentous, heterocyst-forming cyanobacteria are multicellular prokaryotes in which different cell types must communicate and co-operate. In particular, heterocysts and vegetative cells must exchange signals and metabolites. We have used a technique involving fluorescent tracer dyes, confocal microscopy and Fluorescence Recovery after Photobleaching to demonstrate that there are channels allowing the rapid, non-selective of diffusion of small molecules from cell to cell in the filament. These channels are probably the "microplasmodesmata":tiny protein structures observed long ago in electron micrographs that appear to link the cytoplasms of adjacent cells. We have identified a protein known as FraG as the key component of the channels. The activity of the channels is strongly regulated, and this regulation sheds new light on the relationship between the different cells in the filament