Vesicle transport and the cytoskeleton in the unicellular red alga Glaucosphaera vacuolata

Vesicles are continually transported from the perinuclear region to the cell's exterior in the unicellular red alga Glaucosphaera vacuolata Korshikov. This phenomenon is recorded here with time-lapse videomicroscopy. The mechanism governing this intracellular motility is unknown but the cytoskeleton is believed to be involved. Microtubules and actin filaments are located in Glaucosphaera using fluorescently conjugated antibodies and FITC-phallicidin, respectively. Microtubules radiate in all planes from the perinuclear region to the periphery whereas actin filaments form rings around migrating vesicles. This pattern of location might indicate that both microtubules and actin filaments are involved in vesicle transport. However, this conclusion is not confirmed directly because the thick mucilaginous wall material seemed to prevent the entry of cytoskeletal inhibitors. A video clip of vesicle movement is available at http://www.cytographics.com/.