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Carrie McDougall

Keywords: Neurobiology, dinoflagellate, control mechanisms

I am interested in mechanisms of control in dinoflagellate bioluminescence, specifically in Pyrocystis fusiformis.

My ongoing and future projects include:

  • Cytoskeletal transport of bioluminescent organelles and chloroplasts
    In dinoflagellates, bioluminescence is emitted from discrete point sources within the cell. These point sources of light are densifications of the cytoplasm (i.e. not true organelles) and have been given the term scintillons. In Pyrocystis fusiformis scintillons change their location from day to night. When the cell is in dayphase, the scintillons are found in the perinuclear region. In nightphase, the scintillons are distributed along the periphery of the cell. If and how these pseudo-organelles are moved around the cell is unknown. By using various drugs to depolymerize individual components of the cytoskeleton, such as the actin and the microtubules, I am trying to isolate which component is responsible for these movements. I have localized the actin cytoskeleton using a confocal microscope. Currently, I am determining the location of the scintillons with a SIT camera attached to a compound scope, using acetic acid as stimulation.

  • Cytoskeletal involvement in bioluminescent flash
    After depolymerizing a component of the cytoskeleton, I will determine if the cells' ability to produce a mechanically stimulated flash has been affected.

  • Calcium and pH imaging of bioluminescent flash
    The signal transduction pathway for how a mechanical signal is transduced into a bioluminescent flash is poorly understood, particularly in P. fusiformis . Part of this pathway has been shown to involve an action potential that travels along the vacuolar membrane and triggers hydrogen ions to come out of the vacuole and into the scintillon, initiating the bioluminescent reaction. However, the events that lead up to the action potential are unknown. I am looking for ion fluxes that might be linked to the bioluminescent flash using various fluorescent ion indicators. With these indicators I will be able to determine which ions, as well as where and when, are fluxing. Initially, my focus will be on calcium and pH.

Submitted: 11 Sep 97

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Carrie McDougall |
Marine Science Institute | phone: (805) 893-3639
University of California |
Santa Barbara, CA 93106 |
    E-mail .