Undergraduate Honors Theses

Thesis Defended

Spring 2011

Document Type

Thesis

Department

Integrative Physiology

First Advisor

James R. Cypser

Abstract

The ability of an organism to respond to environmental stress is an important indicator of how it will age. Two life-extension protocols, dietary restriction (DR) and hormesis, are thought to extend life by placing stress on an organism which then up-regulates its own stress- response systems. Because many researchers believe that DR is a form of hormesis, it is important to determine whether the genetic pathways behind these two protocols overlap. To answer this question, this study tested 14 candidate genes for requirement in either DR or hormesis. While there was little genetic overlap between DR and hormesis, two genes in the insulin- signaling pathway, daf-16 and daf-18, were partially required for both protocols. Moreover, the mitochondrial ribosomal protein B0261.4 was required for heat-induced hormesis, although the components of the electron transport chain tested were not required. The results of this study indicate two mostly-separate stress- response pathways and suggest that hormesis and DR might not function through the same mechanism. The most interesting result of this thesis is the possible requirement of mitochondrial ribosomal function in heat-induced hormesis. Further investigation into the role of mitochondrial ribosomal genes should be undertaken to determine the extent of requirement of mitochondrial protein translation in heat-induced hormesis.

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