title: Gut-spilling in chordates: evisceration in the tropical ascidian Polycarpa mytiligera.
abstract: The ejection of internal organs, i.e., evisceration, is a well-known phenomenon in sea-cucumbers. We report the ability of a member of the Chordate phyla, the tropical ascidian Polycarpa mytiligera, to eviscerate and regenerate its gut within 12 days, and to rebuild its branchial sac within 19 days. Evisceration occurred within 4-43 seconds of gentle mechanical pressure exerted on the tunic in 47% of the tested P. mytiligera. Individuals were able to discard up to 3/4 of their digestive tract via the incurrent siphon by rupture of the branchial sac in this area. Although chemical analysis revealed no significant levels of toxic compounds, the eviscerated guts were unpalatable to the triggerfish and pufferfish on which they were tested, suggesting evisceration as a defense mechanism. Given the close affinity of ascidians to vertebrates, the regeneration pathway of the viscera and branchial sac of ascidians suggests its potential beneficial application in soft tissue regeneration research.
authors.affiliation: Zoology Department, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.
authors.forename: Noa
authors.initials: N
authors.lastname: Shenkar
authors.affiliation: Zoology Department, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.
authors.forename: Tal
authors.initials: T
authors.lastname: Gordon
mesh_terms: D000818:Animals; D041981:Gastrointestinal Tract / Q000737:chemistry / Q000473:pathology / Q000502:physiology*; D019216:Metals, Heavy / Q000032:analysis; D012038:Regeneration; D013314:Stress, Mechanical; D014561:Urochordata / Q000502:physiology*
chemical_list: D019216:Metals, Heavy