Scholar Profiles
Jenessa
Andrzejewski
2006 - 2007 University Scholar
Mentor: David
Julian
College of Liberal Arts and Sciences
"Through my mentor’s guidance and support, I am learning to navigate through research dilemmas and reevaluate experimental designs. I am also gaining valuable knowledge of managing and conducting an independent research project."
Jenessa Andrzejewski is a senior majoring in integrative biology. She is interested in veterinary science, animal physiology, and the stress tolerance and adaptation of animals living in extreme environments. She will be attending veterinary school at North Carolina State University starting Fall 2007. At UF, Jenessa was a member of the University of Florida Preview Orientation Staff and Pre-Vet Club. As a lab assistant to zoologist David Julian, she worked on functional responses to high temperature, hypoxia and hyposalinity in the clam Merceneria merceneria. In April 2005, she was named University of Florida Resident Assistant of the Month. In her free time, she enjoys spending quality time with her family and friends, hiking and visiting national and state parks.
Research Description:
Sulfide-Induced Autophagy in the Sulfide-Adapted Annelid Glycera Dibranchiata
A variety of annelid worms live in marine environments where they are exposed to the toxin hydrogen sulfide. The epithelial cells of these worms typically contain electron-dense organelles (EDOs), but the origin and function of these organelles are unknown. One possible mechanism for EDO formation is that sulfide damages mitochondria, which initiates a signaling cascade that stimulates mitochondrial autophagy. The resulting autophagosome thereby sequesters damaged mitochondria into EDOs. Based on this model, I have the following hypotheses:
1) sulfide exposure will increase the number of EDOs in a concentration dependent manner
2) the number of EDOs will decrease upon recovery from the sulfide exposure
3) damaged mitochondria will be detected in EDOs following sulfide exposure, and
4) sulfide exposure will increase the expression levels of proteins involved in autophagosome formation and autophagy signaling cascades.
For my experiments, I will investigate the response of the sulfide-adapted annelid Glycera dibranchiata to seven sub-lethal sulfide concentrations. In order to determine the presence of EDOs, a piece of epithelial tissue from each worm will be fixed and stained using enzyme histochemistry for autophagosome-related proteins. The tissues will then be ultra-sectioned and examined using transmission electron microscopy. Expression levels of proteins involved in autophagosome formation and autophagy signaling will be determined by western blotting using up to five specific antibodies.
Although it has been proposed that autophagy is involved in numerous cellular processes in all animals, the regulation of autophagy is not fully understood. By studying sulfide-induced EDOs in G. dibranchiata, and autophagy in general, I hope to gain a better understanding of how autophagy aids organisms living in extreme environments.
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