1 / 18

Plenty of Planaria Laboratory Investigation

The Science and Ethics of Stem Cell Research. Plenty of Planaria Laboratory Investigation. What are Planaria?. Freshwater flatworms (phylum: Platyhelminthes) Live in freshwater under leaves and stones Avoid light (“negative phototaxis”) Free living – not parasites

mead
Download Presentation

Plenty of Planaria Laboratory Investigation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Science and Ethics of Stem Cell Research Plenty of Planaria Laboratory Investigation

  2. What are Planaria? • Freshwater flatworms (phylum: Platyhelminthes) • Live in freshwater under leaves and stones • Avoid light (“negative phototaxis”) • Free living – not parasites • Carnivores – eat decaying meat, insects and larvae (egg yolks or liver in the lab) • 1-20 mm in size • Long lived • Use sexual or asexual reproduction This picture has been released it into the public domain.

  3. Overview of Brown PlanariaDugesia tigrina

  4. Planaria are complex organisms Gastrovascular System

  5. Nervous System

  6. Reproductive System

  7. Excretory/Osmoregulatory System

  8. Planaria have an amazing ability to regenerate parts of themselves Planaria regeneration is a great model for demonstrating stem cell function and complexity of tissue regeneration They can grow easily in the lab Why study Planaria to learn about stem cells? 1/279th

  9. Neoblast = Planaria Stem Cell • 20-30% of all the cells in a planaria are Neoblasts. • Neoblasts divide by mitosis and can make more of themselves. They are the only dividing cells in planaria. • When a planaria is wounded, neoblasts migrate to the site and begin dividing • Neoblasts can become ANY cell the planaria needs—nerve cells, flame cells, reproductive cells… Ann. Rev. Cell. Dev. Biol. 20:725-757, 2004

  10. Three types of planaria with their neoblasts labeled with BrdU BrdU (bromodeoxyuridine) is substituted for thymine during DNA replication. Only dividing cells—in this case the neoblasts—will show detectible amounts of BrdU. A. Phagocata sp. B. Girardia dorotocephala C. Schmidtea mediterranea Dugesia sp. • (Dev. Biol 220: 142-153, 2000)

  11. “Totipotent” Stem Cell can become: Extra Embryonic Blood Nerve Skin They can become any cell type in the body In Humans: Totipotent cells are limited to early embryonic division In Planaria: Neoblasts are always present Neoblasts and Stem Cells are Totipotent

  12. Regeneration requires… turning on the right genes at the right time in the cells that come from the dividing stem cells (neoblast).

  13. Care and Feeding of Planaria • The water is very important! Fresh water from a pond, stream or lake is best; spring water is adequate • Keep cultures in a cool, dark place • Feed planaria at least once a week • Change the water twice a week, especially after feeding • After cutting them, the cultures should not be fed

  14. Plenty of Planaria

  15. Planaria Regeneration, Days 1 - 14 Slide courtesy of Dr. Sánchez Alvarado and Dr. Kyle Gurley

  16. Slide courtesy of Dr. Sánchez Alvarado and Dr. Kyle Gurley

  17. Slide courtesy of Dr. Sánchez Alvarado and Dr. Kyle Gurley

More Related