Coelomocyte motility.
We have utilized a video-enhanced contrast system coupled to a DIC-equipped microscope to examine the motility of both whole coelomocytes and individual filopodia. When the cells are left in diluted coelomic fluid, they exhibit a fibroblast-like mode of translocation across the substrate. These cells extend lamellipodia at their advancing margin and develop retraction fibers at the trailing edge. Filopodia are actively extended from the lamellipodia of the advancing margin. Cells that are washed free of the coelomic fluid and placed in an isotonic buffer lose their ability to translocate. Filopodia on these stationary cells are seen to undergo a series of waving and bending motions. These motions are rapid and result in a filopodium folding back upon itself only to re-extended later. Both forms of motility are discussed in light of the existing structural and biochemical knowledge of this and other cell types.
D000818:Animals; D002465:Cell Movement; D009040:Motion Pictures; D012617:Sea Urchins / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure