Date of Award
Timothy Sherman, Ph.D.
There are many costs associated with increased body size and longevity in animals, including the accumulation of genotoxic and cytotoxic damage that comes with having more cells and living longer. Yet, some species have overcome these barriers and have evolved remarkably large body sizes and long lifespans. Organisms with these unique phenotypes have come under recent genomic scrutiny to discover mechanisms of healthy aging and tumor suppression but little physiological work to validate these mechanisms has been conducted outside of mammals. Here I propose that reptiles, especially testudines (turtles), would be an excellent system to investigate the topics of size and longevity. I also show that reptile cells are amenable to physiological assays used in recent mammalian studies. Turtle fibroblasts were treated with the cytotoxic compounds tunicamycin, paraquat, and etoposide to mimic damage cells may occur over time. Then apoptotic responses were analyzed using Promega’s RealTime-Glo and ApoTox-Glo assays. Preliminary results indicate that turtle cells, in general, are resistant to oxidative stress related to aging, while Galapagos giant tortoise cells, specifically, are sensitive to endoplasmic reticulum stress causing an enhanced apoptotic response, which may give this species an ability to mitigate the effects of cellular stress associated with increased body size and longevity.
Bulls, Stephanie E., "Methods for Assessing Cellular Phenotypes Related to Aging and Longevity in Turtles" (2022). Theses and Dissertations. 61.