Comparison of Planarian ( Dugesia tigrina ) Regeneration Rate in - PowerPoint PPT Presentation

Comparison of Planarian ( Dugesia tigrina ) Regeneration Rate in Caffeine and Aloe vera Solutions Diane Kwon and Joel Tatum Biology 3B Department of Biological Sciences Saddleback College Mission Viejo, CA 92692

Planarians (Dugesia tigrina) o Planarians regenerate after cut 279 cuts  2 new planarians identical  to original planarian  Same memories o Planarians sensitive to concentrated solutions Spring water only  Tap and DI water may kill  planarians

Caffeine and Aloe vera o Caffeine Stimulant  May inhibit cell growth  o Aloe vera Succulent plant  Stimulate cell growth  and healing Mucilage tissue (Aloe  vera gel)

Hypothesis Planarian regeneration rate will decrease in caffeine and Aloe vera solutions compared to that of spring water.

Materials and Methods o Planarians purchased from Carolina Biological Supplies (n=30) o 3 solutions Arrowhead spring water (control)  Caffeine (0.00001 M)  Aloe vera (0.00019%)  o Planarians fed 3 days before experiment but not during Proportion-readjustment  regeneration  Cells self-destruct to provide energy/nutrients for regeneration

Materials and Methods o Transverse cut anterior to pharynx o Observed transected tail portion  Head development more distinct o Experiment duration - 23 days  Oct 26, 2015 to Nov 18, 2015

Planarian Regeneration 1 1. Stage 1: wound healing Neoblasts: population of • stem cells 2. Stage 2: blastema formation 2 Cell proliferation •

Planarian Regeneration 3. Stage 3: growth 3 4. Stage 4: differentiation 4

Image from: http://www.extremetech.com/extreme/161092-decapitated-worms-can-regenerate-their-brains-and-the-memories-stored-inside

Results o Single-factor ANOVA Bonferroni Correction post-hoc test o No significant difference (p=0.0726)

Discussion o Caffeine diverts energy from regeneration o Healing properties of caffeine and Aloe vera in lower concentrations Below lethal limit  Potential for growth stimulation  Sensitivity of planarians to higher concentration of solutes  o Inconsistent regeneration rate through stages of regeneration

Acknowledgments Thank you, Professor Teh, for supplies and guidance. Thank you, Saddleback College Department of Biological Sciences, for providing necessary resources. Thank you, caffeine, for getting us through the project, even though it inhibited planarian regeneration. (Poor little guys…)