The actin cytoskeleton organization and disorganization properties of the photosynthetic dinoflagellate Symbiodinium kawagutii in culture.

The actin cytoskeleton organization in symbiotic marine dinoflagellates is largely undescribed; most likely, due to their intense pigment autofluorescence and cell walls that block fluorescent probe access. Using a freeze-fracture and fixation procedure, we observed the actin cytoskeleton of Symbiodinium kawagutii cultured in vitro with fluorescently labeled phalloidin and by indirect immunofluorescence with monoclonal antibodies specific for actin. The cytoskeleton appeared as an organized network with interconnected cortical and cytoplasmic thick filaments, along with some intertwined fine filaments.