Date of Completion

2021

Thesis Type

College of Arts and Science Honors

Department

Biology

First Advisor

Brent Lockwood

Keywords

Mitochondria, membrane, fluidity, Drosophila, fluorescence anisotropy, thermal acclimation

Abstract

The fruit fly, Drosophila melanogaster, is an ectotherm with various populations occupying thermal environments across a wide latitudinal range. These populations are differentially thermally adapted to their natural environments, and thus have altered physiologies in response to thermal stress. It has been previously shown that populations of D. melanogaster alter the composition of their lipid constituents in response to thermal acclimation to preserve fluidity through a process known as homeoviscous adaptation (HA). The goals of this experiment were to determine if this process was occurring in the mitochondrial membranes of acclimated tropical and temperate genotypes of D. melanogaster. Mitochondrial membrane fluidity was measured through the use of the fluorescent probe 1-(4-Trimethylammoniumphenyl) -6-Phenyl-1,3,5-Hexatriene p-Toluenesulfonate (TMA-DPH) and fluorescence anisotropy. I predicted that the tropical genotype would have a more rigid membranes than the temperate genotype, the cold acclimation group would have more fluid membranes than the warm acclimation group, and that the temperate genotype would exhibit greater membrane plasticity across acclimation. For both genotypes, there was an increase in membrane fluidity with acclimation temperature, which is opposite to what would be expected if HA were occurring. Interestingly, genotypes exhibited greater plasticity when acclimated at temperatures that would be normally encountered in their natural environments but not outside that range. With global temperatures rising, it appears that neither genotype is especially better equipped to handle a rapidly changing environment. However, the greater plasticity shown by the tropical genotype at higher acclimation temperature could suggest that it is better suited to handle future increases in temperature.

Available for download on Wednesday, May 11, 2022

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