Dealing with a deadly diet : molecular mechanisms of alkaloid sequestration in poison frogs
Abstract/Contents
- Abstract
- Chemical defense is a widespread phenomenon where organisms employ toxic compounds as a means of protection against predators. Poison frogs (family Dendrobatidae) sequester an array of alkaloid toxins onto their skin from their diet for chemical defense, and often possess aposematic signals warning potential predators of their toxicity. Although the skin alkaloids, coloration, and dietary resources of poison frogs have been rich areas of research in the last 40 years, little is known about the molecular mechanisms involved in their ability to uptake alkaloids from their diet. My dissertation focused on applying comparative biochemical and genetic approaches to better understand the molecular processes involved in toxin sequestration, metabolism, and autoresistance. In Chapter 2 I investigate the effects of dietary pumiliotoxin 251D (PTX) on gene expression and identify a candidate cytochrome P450 protein involved in PTX hydroxylation. Chapter 3 focuses on an unlikely member of the serine protease inhibitor family, alkaloid binding globulin (ABG), as a transporter of alkaloids in poison frog plasma. In Chapter 4 I compare the alkaloid and transcriptomic profiles of toxic, moderately toxic, and non-toxic poison frogs, unraveling the molecular correlates of toxicity and autoresistance. This work expands our understanding of PTX metabolism, identifies potential candidate enzymes involved in alkaloid hydroxylation, and sheds light on the multifaceted physiological roles played by serpin proteins, exemplified by ABG. Furthermore, we challenge the conventional notion of toxicity as a binary trait and suggest that gene expression plasticity may be a key aspect of poison frog evolution. Potential avenues for future work include testing poison frog cytochrome P450 proteins for metabolic activity, exploring the functional diversity of serpin proteins, and more comprehensive analyses of poison frog genomes, transcriptomes, and alkaloid profiles. Overall, we applied experimental techniques to better understand the molecular underpinnings of chemical defense in poison frogs, paving the way for future work in poison frog physiology.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2023; ©2023 |
| Publication date | 2023; 2023 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Alvarez-Buylla, Aurora |
|---|---|
| Degree supervisor | O'Connell, Lauren |
| Thesis advisor | O'Connell, Lauren |
| Thesis advisor | Cyert, Martha |
| Thesis advisor | Du Bois, Justin |
| Thesis advisor | Long, Jonathan |
| Degree committee member | Cyert, Martha |
| Degree committee member | Du Bois, Justin |
| Degree committee member | Long, Jonathan |
| Associated with | Stanford University, School of Humanities and Sciences |
| Associated with | Stanford University, Department of Biology |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Aurora Alvarez-Buylla. |
|---|---|
| Note | Submitted to the Department of Biology. |
| Thesis | Thesis Ph.D. Stanford University 2023. |
| Location | https://purl.stanford.edu/sg549rd3140 |
Access conditions
- Copyright
- © 2023 by Aurora Alvarez-Buylla
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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