Life Sciences Commons^™

Physiological And Evolutionary Implications Of The Pattern Of Expression Of Oxygen-Binding Hemoproteins In Antarctic Notothenioid Fishes, Kimberly Borley

Electronic Theses and Dissertations

Antarctic icefish do not express hemoglobin (Hb). Icefishes possess cardiovascular modifications including increased densities of blood vessels, larger ventricles and increased blood volume compared to red-blooded relatives. In addition to delivering oxygen to tissues, Hb degrades nitric oxide (NO), a small signaling molecule. To investigate the mechanism driving development of icefish cardiovascular characteristics, I present and test the hypothesis that loss of Hb results in increased steady-state levels of NO, triggering downstream signaling pathways such as angiogenesis. I measured NO breakdown products, as a proxy for NO, and found that icefish have higher steady-state levels of NO metabolites in their …

Alteration Of Nucleotide Excision Repair By Estrogens: Implications For Carcinogenesis, Emily Glynn Notch

Electronic Theses and Dissertations

Estrogens and estrogen mimics represent a wide range of aquatic contaminants that elicit deleterious effects on exposed organisms. Despite well-characterized reproductive effects of environmental estrogens, less is known about non-reproductive impacts of exogenous estrogen exposure. Additionally, estrogens are known carcinogens, implicated in multiple human cancers. Little or no research has examined the effects of xenoestrogens on DNA repair despite being known carcinogens. The goal of this research was to test the hypothesis that aquatic estrogens enhance the effects of environmental mutagens by altering DNA repair. Of particular interest is nucleotide excision repair (NER), the only repair pathway to remove structurally …

Mechanistic Importance Of Redox Potentials And Conformational Flexibility In Electron-Transferring Flavoproteins, Michael Anthony Swanson

Electronic Theses and Dissertations

The mitochondrial matrix flavoproteins electron transfer flavoprotein (ETF) and electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO) are responsible for linking fatty acid β-oxidation with the main mitochondrial respiratory chain. Electrons derived from flavoprotein dehydrogenases are transferred sequentially through ETF and ETF-QO to ubiquinone and then into the respiratory chain via complex III. In this study, the effects of changes in ETF-QO redox potentials on its activity and the conformational flexibility of ETF were investigated.

ETF-QO contains one [4Fe-4S]^2+,1+ and one flavin adenine dinucleotide (FAD). In the porcine protein, threonine 367 is hydrogen bonded to N1 and O2 of the flavin ring …