Stefanie F. Kühn, Colin Brownlee
Membrane organisation and dynamics in the marine diatom Coscinodiscus wailesii (Bacillariophyceae)
The membrane dye FM1-43 was used to visualise membrane internalisation in living cells of the marine centric diatoms Coscinodiscus wailesii and Thalassiosira punctigera. The results revealed dynamic and selective membrane trafficking and several cellular structures which have not been described in light microscopical studies. Intimate and regular contacts were found between the plasma membrane and the labiate processes and the inner face of the frustule in C. wailesii. The central cytoplasmic region close to the tonoplast and growing parts of the silica deposition vesicles became labelled, indicating that they were involved in membrane recycling. We never observed labelling of chloroplasts, nucleus or the vacuolar contents. These studies also revealed a novel perinuclear region that appeared not to show significant membrane turnover. When the cytoplasm was impaled with a micropipette, membranous material rapidly accumulated at the tip of the micropipette, presumably expelling it from the protoplast. This could be an effective defence mechanism against certain invasive pathogens, and further illustrates the highly dynamic nature of the endomembrane system.
Botanica Marina, Walter de Gruyter
Print ISSN: 0006-8055
Volume: 48, 10/2005
Pages: 297 - 305
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