The role of the hyaline spheres in sea cucumber metamorphosis: lipid storage via transport cells in the blastocoel.

Show simple item record Peters-Didier, Josefina en Sewell, Mary en 2019-06-13T02:45:59Z en 2019-01 en
dc.identifier.citation EvoDevo 10:8 Jan 2019 en
dc.identifier.issn 2041-9139 en
dc.identifier.uri en
dc.description.abstract Background:For echinoderms with feeding larvae, metamorphic and post-settlement success may be highly dependent on larval nutrition and the accumulation of energetic lipids from the diet. In contrast to the sea urchins, starfish and brittle stars within the Phylum Echinodermata, sea cucumber metamorphosis does not involve formation of a juvenile rudiment, but instead there is a rearrangement of the entire larval body. Successful metamorphosis in sea cucumbers is often associated with the presence in the late auricularia stage of an evolutionary novelty, the hyaline spheres (HS), which form in the base of the larval arms. Known since the 1850s the function of these HS has remained enigmatic-suggestions include assistance with flotation, as an organizer for ciliary band formation during metamorphosis and as a nutrient store for metamorphosis. Results:Here using multiple methodologies (lipid mapping, resin-section light microscopy, lipid and fatty acid analyses) we show definitively that the HS are used to store neutral lipids that fuel the process of metamorphosis in Australostichopus mollis. Neutral lipids derived from the phytoplankton diet are transported by secondary mesenchyme cells ("lipid transporting cells", LTC), likely as free fatty acids or lipoproteins, from the walls of the stomach and intestine through the blastocoel to the HS; here, they are converted to triacylglycerol with a higher saturated fatty acid content. During metamorphosis the HS decreased in size as the triacylglycerol was consumed and LTC again transported neutral lipids within the blastocoel. Conclusion:The HS in A. mollis functions as a nutrient storage structure that separates lipid stores from the major morphogenic events that occur during the metamorphic transition from auricularia-doliolaria-pentactula (settled juvenile). The discovery of LTC within the blastocoel of sea cucumbers has implications for other invertebrate larvae with a gel-filled blastocoel and for our understanding of lipid use during metamorphosis in marine invertebrates. en
dc.format.medium Electronic-eCollection en
dc.language eng en
dc.relation.ispartofseries EvoDevo en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights.uri en
dc.rights.uri en
dc.title The role of the hyaline spheres in sea cucumber metamorphosis: lipid storage via transport cells in the blastocoel. en
dc.type Journal Article en
dc.identifier.doi 10.1186/s13227-019-0119-4 en
pubs.begin-page 8 en
pubs.volume 10 en
dc.rights.holder Copyright: The authors en
pubs.publication-status Published en
dc.rights.accessrights en
pubs.subtype research-article en
pubs.subtype Journal Article en
pubs.elements-id 769303 en Science en Biological Sciences en
dc.identifier.eissn 2041-9139 en
pubs.record-created-at-source-date 2019-04-23 en
pubs.dimensions-id 31007889 en

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