Physiology and morphology of epithelia in the freshwater demosponge, Spongilla lacustris

• Author / Creator

  Adams, Emily

• Epithelia form protective barriers and regulate molecule transport between the mesenchyme and environment. Amongst all metazoans, only sponges are said to lack 'true' epithelia however the physiology of sponge cell layers are rarely studied empirically. Aggregates and gemmules of a freshwater demosponge, Spongilla lacustris, were used to grow confluent tissue over permeable culture wells which are required for transepithelial recordings. The transepithelial potential (TEP) of S. lacustris was slightly negative (-3mV), indicating possible control of ion transport. Transepithelial resistance (TER) was recorded between 1-2 k Ωcm2, the same order of magnitude as many vertebrate epithelia. Cultures with high resistance blocked the passage of the small tracer molecules 14C-PEG, 3H-Inulin and ruthenium red. Pinacocytes were spatially stable over time and epithelial layers were morphologically similar in freshwater and marine species. These results suggest that sponge cell layers are able to control solute and ion transport, the physiological attributes of functional epithelia.

• Subjects / Keywords

  • Epithelia
  • Occusion junctions
  • Evolution
  • Sponge
  • Metazoa
  • Invertebrate
  • Transepithelial Resistance
  • Porifera
  • Spongilla lacustris

• Graduation date

  Fall 2010

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3X98C

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.