Date of Award

Spring 2018

Document Type

Thesis Restricted

Degree Name

Master of Science (MS)

Department

Biology

Committee Chairperson

Oné R. Pàgan, PhD

Committee Member

Josh R. Auld, PhD

Committee Member

Gustave Mbuy, PhD

Abstract

The purpose of this study was to determine the effects of ethanol (EtOH) on the planarian Dugesia tigrina’s behavior and regeneration. EtOH is a teratogen which studies have shown affect brain function and regeneration time in planarians. Planarian regeneration experiments were carried out in order to gain insight in how EtOH affects their regeneration process.

The experiments carried out in this study were to observe motility, c-like movements, regeneration, and light/dark preference. The concentrations used in the motility experiments ranged from 2 to .125% EtOH. Results show that as the concentration of EtOH increases, motility decreases. To observe if size made a difference in motility when exposed to EtOH, each worm was measured. This set of trials only uses 1% EtOH. Results demonstrated that size does not make a difference. C-like movements experiments used EtOH concentrations from 2.5 to .0625% EtOH. C-like movements occurs when the planarian forms a c shape with its body when exposed to a stressor. As the concentration of EtOH increases, more c-like movements were observed. Size of the worm was also observed in this experiment and it was found that length of the worm did not difference.

In the regeneration experiments, results indicated that as EtOH concentration increases, regeneration time increases. The concentrations used ranged from 2 to .125%.

The control worms kept in artificial pond water (APW) regenerated completely by days 5 and 6. The ones in EtOH were completely regenerated by days 6-11, depending in the concentration of EtOH they were incubated in.

In order to observe if the central nervous system (CNS) development is affected by EtOH, worms were regenerated in APW and exposed to cytisine on days 0, 3, 7, and 10. The controls in this experiment were intact worms incubated in APW. When an intact worm is exposed to cytisine, it reacts by twitching (c-like movement). Cytisine was used in this experiment in order to see if the planarian’s brain regained full function even though it was regenerated in EtOH.

Results demonstrated that by day 10, planarian seizure-like movements caused by cytisine were observed but in a lesser degree as compared with the intact worms. Therefore, EtOH appears to affects CNS development. EtOH was also tested to see if it alters the worm’s negative phototaxis. The results show that as the concentrations of EtOH increases, the more time the worm spends in the light than the dark. This thesis provides evidence pointing at the harmful effects of EtOH in planarian regeneration and behavior.

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