Planaria regeneration lab
- Page ID
- 70084
Learning Objectives
- State reasons why model organisms are used in biological research.
- Explain why planaria is a useful model to study regeneration.
- Design an experiment to test planarian regeneration.
Pre-Lab
Planarians are flatworms with a remarkable ability to regenerate lost tissues.
Pre-Lab Questions
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What is regeneration?
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How is regeneration important in not only Planaria but within the broader animal kingdom? Include examples of regeneration in other organisms.
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What are neoblasts and what is their significance?
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How does the study of mitosis relate to the study of regeneration? Is mitosis sufficient for regeneration? Why or why not?
Week 1
- Observe the planaria and answer the questions in Table 1.
- To observe the anatomy on low power on the compound scope, place a ring of petroleum jelly on a coverslip. Place a planarian in the center with a drop of spring water, place a second coverslip on top and gently press flat. Observe both dorsal and ventral surfaces in this way.
Table 1: Planaria Observations
| Are the planaria moving? If so, describe the movement. |
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|---|---|
| Are the dorsal and ventral sides evenly pigmented? If not, what are the differences? |
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| What features, structures or organs can you identify? |
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| Do planaria respond to movement of the dish or to touch (like a gentle touch with a paintbrush)? If yes, how could you measure this movement? |
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| Do planaria respond to light? If yes, how could you measure this response? |
|
Experimental Design
1. Propose a cut pattern that you think might introduce abnormal regeneration (see examples in http://people.physics.illinois.edu/Selvin/PRS/498IBR/Planarian%20Regeneration_annurev.cellbio.2004.Reddien.pdf)
2. Explain what you will measure and how you will measure it each week.
Examples: length, response to touch, speed/movement, response to light etc.
Create a data table (on paper or in a Excel/Sheets etc) to show how you will collect your observations.
3. Draw the cut you intend to make and the expected pattern of regeneration.
4. Show your plans to your Instructor
Dissection procedure
1. Photograph the planarians “pre-dissection.”
Think about what your final photos will look like. What orientation do you want them to be in? How bright is the light? What magnification? You could consider taking several different versions of an image.
2. To prepare for dissections, Label dishes fill each dish with approximately 9mL of spring water.
3. Obtain a prepared ice box, remove the lid. Wait for it …. until a layer of water appears on the top of the box.
○ You don’t want to place the worm directly onto the ice. Why not?
4. Use a paintbrush to transfer one planarian onto the box. Wait for it to slow its movement.
5. Use a scalpel to make your cut.
6. Transfer the pieces to the dishes with spring water. Label each dish and document with a photograph.
7. Repeat steps 5-10 if needed for all of your planaria.
8. If your control is an uncut planaria, you should still put it on ice and then remove it without cutting.
9. Observe each cut piece every few minutes. You should be able to view muscular contractions that close the wound within about 10 minutes, followed by the epithelial cells spreading.
10. An unpigmented region called a blastema will form at the cut site over the next 1-2 days.
Week 2
Photograph your planaria.
Collect the measurements you planned and record in your table.
Week 3
Photograph your planaria.
Collect the measurements you planned and record in your table.
Post-Lab Report
Guidelines will be provided by your instructor.