Date of Award

Spring 2013

Document Type

Restricted Thesis

Terms of Use

© 2013 Curran K. Bice. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts


Biology Department

First Advisor

Elizabeth Ann Vallen


The symbiotic sea anemone Aiptasia pallida and its algal symbiont Symbiodinium are a model system for other symbiotic cnidarians such as corals. Because corals are important to biodiversity and to economics world wide, and because coral bleaching, the loss of symbionts, is harmful to corals, a better understanding of the cnidarian-symbiont relationship is of interest. In this study we investigate the role of the collagen modifying protein prolyl-4-hydroxylase (P4HD) in the Symbiodinium trafficking process and in the symbiotic state in general. We investigated the effects of the prolyl-4-hydroxylase inhibitor ethyl-3,4-dihydroxybenzoate on the ability of a bleached anemone to traffic newly acquired symbionts. Anemones treated with the inhibitor trafficked significantly fewer symbionts from their stalk to their tentacles after 6 days. We also analyzed the transcription of three P4HD gene homologues. We used semiquantitative RT-PCR to compare transcript levels between aposymbiotic and symbiotic anemones. We found one P4HD gene that is downregulated in symbiotic anemones, but none that were upregulated in symbiotic anemones. Taken together, these suggest the importance of collagen processing, and perhaps the anemones' collagenous mesoglea, in the onset and stable state of symbiosis.