Piston (subcellular structure)

Light micrograph of a cell, translucent pink with darkly pigmented ocelloid retinal body at upper left and light, straight piston projection at bottom center.
An isolate of Erythropsidinium. The arrow indicates the piston; the double arrowhead indicates the ocelloid. Scale bar 20 μm.[1]

A piston (also known as a dart, prod, or tentacle) is a complex contractile organelle found in some dinoflagellates, namely the Erythropsidinium and Greuetodinium genera of the family Warnowiaceae. This group is also well known for possessing other unusually complex subcellular structures such as the ocelloid and nematocyst. Observations of Erythropsidinium samples reveal that the length of the piston is highly variable across specimens. The piston is known to be capable of repetitive and dramatic contractile motion; although its function is unknown, roles in locomotion, prey capture, and defense have been suggested.[1][2]

  1. ^ a b Hoppenrath, M; Bachvaroff, TR; Handy, SM; Delwiche, CF; Leander, BS (25 May 2009). "Molecular phylogeny of ocelloid-bearing dinoflagellates (Warnowiaceae) as inferred from SSU and LSU rDNA sequences". BMC Evolutionary Biology. 9: 116. doi:10.1186/1471-2148-9-116. PMC 2694157. PMID 19467154.
  2. ^ Gómez, Fernando (November 2008). "Erythropsidinium (Gymnodiniales, Dinophyceae) in the Pacific Ocean, a unique dinoflagellate with an ocelloid and a piston". European Journal of Protistology. 44 (4): 291–298. doi:10.1016/j.ejop.2008.03.002. PMID 18550346.