Submission Date

4-26-2015

Document Type

Paper- Restricted to Campus Access

Department

Biology

Adviser

Dr. Rebecca Kohn

Committee Member

Dr. Rebecca Kohn

Committee Member

Dr. Dale Cameron

Committee Member

Prof. Jeanine McCain

Department Chair

Dr. Peter Small

Project Description

Reactive oxygen species (ROS) may cause oxidative stress in cells if insufficient antioxidants are present to neutralize them. When this occurs in neurons it may result in neurodegeneration due to apoptosis or necrosis, which can contribute to the progression of Alzheimer’s and Parkinson’s diseases. Increased neural activity may have a protective effect against oxidative stress and progression of these disorders, however the presence of dopamine may result in higher levels of neurodegeneration due to the ease of dopamine oxidation and the damage this may cause. In order to determine the mode of neurodegeneration, apoptosis or necrosis, caused by oxidative stress, strains of the nematode Caenorhabditis elegans were exposed to hydrogen peroxide to induce oxidative stress. The dopaminergic neurons of all strains were labeled with green fluorescent protein (GFP) driven by the dat-1 promoter. Trial strains also contained mutations in unc-13, ced-3, or dat-1 which cause paralysis due to reduced neural activity, a defective apoptotic pathway, and defective dopamine reuptake transporters respectively. Neurons were viewed using fluorescence microscopy to assess neurodegeneration. Loss of GFP-labeled neurons increased following hydrogen peroxide exposure in both wild-type and unc-13 strains. ced-3 mutants exposed to hydrogen peroxide showed decreased loss of GFP compared to both wild type and unc-13 strains, suggesting that apoptosis is the method of cell death in some dopaminergic neurons exposed to ROS. The strain containing the dat-1 mutation has not been completed at this time, however primers have been designed to detect both the mutant allele of the gene and the wild-type allele.

Comments

Partially funded by the HHMI grant for the Ursinus College Center for Science and the Common Good and the FUTURE program

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