Date of Graduation

5-2024

Document Type

Thesis

Degree Name

Bachelor of Science in Biology

Degree Level

Undergraduate

Department

Biological Sciences

Advisor/Mentor

Paré, Adam

Committee Member/Reader

Girodat, Dylan

Committee Member/Second Reader

Bailey, Tameka

Committee Member/Third Reader

Stauss, Kim

Abstract

Mitochondria are not static organelles, but instead are dynamic networks that undergo rapid changes in subcellular distribution, organization, and activity in response to external stimuli. Notably, mitochondria can undergo fission and fusion, collectively known as mitochondrial dynamics. Mitochondrial fusion creates assembled networks of mitochondria that are maximally efficient at generating ATP through oxidative phosphorylation. Conversely, mitochondrial fission leads to network fragmentation and a shift towards glycolysis, which is the dominant mode of ATP generation in oxygen-limiting and stressed conditions. While mitochondrial dynamics have been intensively studied in isolated cells under stressful conditions, much less is known about how mitochondria behave during normal development in healthy tissues. The resulting system is an adaptable network, able to adjust to different physiological demands and mechanical stressors. Mitochondrial dynamics are thought to be an integral component of embryonic development, but they have only been well described in a few contexts. Drosophila melanogaster (the fruit fly) is a potentially excellent model organism for studying mitochondrial networks during embryonic development, as they develop rapidly and are amenable to microscope-based studies. However, the intricacies of mitochondrial behavior and networking during early Drosophila gastrulation and head-to-tail axis elongation (convergent extension) are poorly characterized. The overall goal of this project is to characterize mitochondrial networking prior to and during convergent extension in Drosophila melanogaster early embryogenesis to increase our knowledge of the importance of mitochondrial dynamics during normal development. To address this gap, I performed live and fixed-tissue analyses using fluorescent molecular tags and laser-scanning confocal microscopy to visualize mitochondrial networks over time in wild-type Drosophila embryos. In particular, I developed a detailed timeline of how mitochondrial networks are organized prior to and during convergent extension. Second, I tested the effects of disrupting mitochondrial fission by knocking down levels of Drp1. Future experiments will build on these findings by quantifying three-dimensional network organization in embryos in which mitochondrial dynamics have been disrupted.

Keywords

mitochondrial dynamics; mitochondria; characterization; Drosophila

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