Studies assessing insulin signaling dependent neuronal morphology and novel animal sorting methods in a C. elegans model

Abstract

The purpose of this work is two-part. The primary goal of this thesis is to identify a list of significant target insulin-like peptides (ILPs) that influence the maintenance of neuronal morphology in an aged animal model of Caenorhabditis elegans (C. elegans) and determine whether or not morphological changes have bearing on neuronal function. The second goal is to address and devise a solution for a common laboratory difficulty encountered within the research community, difficulty maintaining large age-synchronous populations of the model organism, C. elegans. Chapter 1 discusses the importance of insulin signaling and how it pertains to the morphology of aging neurons. A reverse genetic screen was conducted to knockdown the expression of individual ILPs in a C. elegans model. The results identify a subfamily of ILPs that play significant roles in maintaining regular morphology of aging mechanosensory neurons. These data corroborate previously published work demonstrating that aberrant morphology of mechanosensory neurons does not directly influence their function and that these two parameters, morphology and function, can be uncoupled and considered mutually exclusive. Chapter 2 describes a main difficulty associated with using C. elegans as a model organism; the problem of maintaining a large age-synchronous population on solid media. To address this difficulty a novel piece of equipment, named the Caenorhabditis Sieve, and an accompanying methodology for its application, were created to mechanically sort and clean C. elegans. The use of this new device facilitates the implementation of assays with animals cultivated on solid media that are normally cost and resource prohibitive. Presented with the protocol for device construction and implementation, are standard experiments that were conducted to verify "proof of concept" of the tool's efficacy. The results demonstrate that the Caenorhabditis Sieve effectively transfers animals from one culture plate to the next in a manner that does not influence common markers of physiological stress; thus validating the sieve's use in future experiments among the research community, as well as highlighting the success of creating a cost-effective, efficient, fast, and simple process to mitigate difficulties and ease progress in research fields using small model organisms.