Ask A Scientist Molecular Biology Archive

name Kenneth 
status other 
grade other 
location PA 

Question - Hello, basically I have two related questions. 
1) I am working with Planaria in school(standard cut to see if they grow 
back stuff). Part of the assignment allows for us to run our own 
experiment and during class the teacher commented on how it is debated 
whether or not the worms regenerate along the cut line or if there is 
some reserve of undifferentiated cells in its body that migrate to the 
cut. Is it known where/how they regenerate? 
2) I have thought of three different experiments which both require 
dyeing a living worm. The 1st one would be to dye the worm at the cut 
point and see if the line moves forward as the worm regen or if the line 
stays in place. 2nd dye the worm several different colors (bands of 
colors) to see if it's possible to locate cells that migrate to the wound 
(I would think this would be difficult both dying multiple colors and 
actually seeing dyed cells that moved) 3rd dyeing a specific tissue type 
(such as nerves or skin) I think nerve tissue would be the best candidate 
as long as it divides relatively slow. 
For all these I would need a dye that would show up under a light 
microscope and would not kill the worm or retard growth. Is there such a 
thing?
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This is a very difficult project. I don't dyes would work because they will 
diffuse too much and they would have to be injected intra-cellularly.

Using a search engine, search under "planaria regeneration stem cells"

Ron Baker, Ph.D.
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