ORCID Identifier(s)

0000-0002-5428-7137

Graduation Semester and Year

2017

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Quantitative Biology

Department

Biology

First Advisor

Todd Castoe

Abstract

Snakes represent an emerging model in biological research and provide a valuable system for studying multiple extreme phenotypes unparallel to those seen in mammals. Recently, snakes have become increasingly used in studies of extreme organ regenerative growth due to the ability of some species to rapidly and reversibly upregulate organ form and function upon feeding. The predominant model used to study this feeding response has been the Burmese python (Python molurus bivittatus) because of the particulalry extreme nature of this post-feeding response in this species. Specifically, the wet masses of major organs increase by 50-100% within just 48 hours post-feeding with rapid spikes in metabolism greater than those seen in any other vertebrate. Once digestion is complete, organs rapidly atrophy back to fasted levels. My transcriptome analyses have implicated the differential expression of thousands of genes during this feeding response, and many of these genes are involved in key cellular pathways, including cell cycling, apoptosis, and WNT signaling. Post-feeding organ regenerative growth has also been demonstrated in other species of snakes, including the vipers. By leveraging comparative transcriptomic data from species that do and do not regenerate their organs upon feeding, my dissertation work has uncovered several key growth and stress response pathway that appear to regulate regenerative growth in the Burmese python and rattlesnake. Specifically, it seems that mTOR interacts with several growth pathways, including PI3K-AKT, MAPK, and lipid signaling pathways to coordinate this growth response across time. Additionally, consistent activation of the NRF2-mediated oxidative stress response during growth likely leads to protection of the cells against apoptosis during extreme functional and metabolic fluctuations.

Keywords

Burmese python, Snakes, Organ regeneration, Pathway analysis, Transcriptomics, Gene expression

Disciplines

Biology | Life Sciences

Comments

Degree granted by The University of Texas at Arlington

Included in

Biology Commons

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