Comparison of Planarian (Dugesia tigrina) Regeneration Rate in Caffeine and Aloe

vera Solutions

Diane Kwon and Joel TatumBiology 3B

Department of Biological SciencesSaddleback 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 verao Caffeine

Stimulant May inhibit cell growth

o Aloe vera Succulent plant Stimulate cell growth

and healing Mucilage tissue (Aloe

vera gel)

HypothesisPlanarian regeneration rate will decrease in caffeine and Aloe verasolutions compared to that of spring water.

Materials and Methodso 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 Methodso Transverse cut anterior to

pharynxo Observed transected tail

portion Head development more

distinct

o Experiment duration - 23 days Oct 26, 2015 to Nov 18, 2015

Planarian Regeneration1. Stage 1: wound healing

• Neoblasts: population of stem cells

2. Stage 2: blastema formation• Cell proliferation

1

2

Planarian Regeneration3. Stage 3: growth

4. Stage 4: differentiation

3

4

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

Resultso Single-factor ANOVA

Bonferroni Correction post-hoc test

o No significant difference (p=0.0726)

Discussiono Caffeine diverts energy from regenerationo 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

AcknowledgmentsThank 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…)