Life Sciences Commons^™

Structural Studies Of Membrane-Assembled Popd And Popb, The Pseudomonas Aeruginosa Type 3 Secretion Translocators, Fabian B Romano Chernac

Doctoral Dissertations 1896 - February 2014

Transport of proteins across membranes is essential during many stages of pathogen infection and colonization of human cells. Many Gram-negative pathogens use a Type 3 Secretion (T3S) system to inject proteins into the target cell during infection. Substantial genetic and biochemical evidence suggest that proteins are translocated across the host plasma membrane through a proteinaceous pore or translocon formed by two bacterial secreted proteins: the T3S translocators. Despite its key role in pathogenesis, virtually nothing is known about the assembly mechanism, structure, and composition of this critical transmembrane complex.

To this end, a cell-free system for the structural and functional …

Factors Influencing The Stability Of Carotenoids In Oil-In-Water Emulsions, Caitlin Suzanne Boon

Doctoral Dissertations 1896 - February 2014

Lycopene has recently received interest as an antioxidant in human tissues. These same antioxidant properties present challenges in preventing oxidative degradation within food products. In this research, degradation of lycopene in model emulsion systems was examined to better understand the chemical stability of this potential functional food ingredient.

Lycopene in corn oil or hexadecane was used to make oil-in-water emulsions using small molecule surfactants. Emulsion color loss was used to estimate lycopene loss and was monitored using an integrating sphere. Lipid hydroperoxide and hexanal formation was used to monitor the development of lipid oxidation.

Oxidation and color loss were found …

Antioxidant Distribution And Effectiveness In A Model Muscle System, Ann T Ballesteros

Doctoral Dissertations 1896 - February 2014

Gallic acid esters (GAE) of varying alkyl chain length were used to determine how antioxidant physical location and partitioning influence hemoglobin-catalyzed lipid oxidation. Specific GAE used were propyl gallate (PG), octyl gallate (OG), and lauryl gallate (LG). GAE partitioning experiments were performed with either isolated cod muscle membranes or washed cod muscle, which primarily contain polar membrane lipids and myofibrillar proteins. Canola oil was used in some experiments to determine how neutral lipids impact partitioning behavior. GAE distribution was determined spectrophotometrically in the recovered membranes, aqueous phase, and oil layer after employing differential centrifugation. Oxidation was monitored by measuring thiobarbituric …

Landscape Ecology Of Large Fires In Southwestern Forests, Usa, Sandra L Haire

Doctoral Dissertations 1896 - February 2014

The recent increase in large fires in southwestern forests has prompted concern regarding their ecological consequences. Recognizing the importance of spatial patterns in influencing successional processes, I asked: (1) How do large fires change plant communities?; (2) What are the implications of these changes for ponderosa pine forests?; and (3) What is the relationship of fire severity to gradients of climate, fuels, and topography? To address the first two questions, I studied succession in the woody plant community at two sites that burned in high-severity fire: La Mesa fire in northern New Mexico (1977) and Saddle Mountain in northern Arizona …