University Honors Program
Recent Submissions
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Patel, Bhavini Narendrakumar (March 20, 2008)[more][less]
Abstract: Salmonella typhimurium is a bacterium that causes many food-borne illnesses such as gastrointestinal infections, diarrhea, and abdominal cramps. It affects 700,000 to 3.8 million people each year. The SseB protein, a part of the Salmonella Pathogenicity Island II (SPI2), plays a critical role in the pathogenesis of gastrointestinal infections. It is part of the Type III Secretion System (TTSS) that is involved in translocating proteins from the bacteria to the host gastro intestinal-epithelial cells. The aim of the research project is to clone, purify the SseB protein from Salmonella typhimurium and obtain a diffracting-quality crystal that will give high resolution data so that the structure of the protein can be determined using x-ray diffraction patterns. The SseB gene was amplified and cloned into pET30b vector and transformed into E. coli novablue cells. The SseB protein is then expressed into E. coli BL21 cells and purified using various chromatographic methods. Purified protein was used for crystallization and diffracting quality crystals were obtained using grid screening method. SseB protein crystallized in P-orthorhombic space group (P 21 21 21) and diffracted to 3.8Å. Further optimization is underway to get a good diffracting quality crystal. It is important to determine the crystal structure of SseB since this will reveal its role in the interaction with other translocation complex such as (SseC and SseD). Based on the structural information, potential drug targets can be designed for translocon complex, which can further prevent diseases caused by the bacterium Salmonella and other closely related bacteria. URI: http://hdl.handle.net/1969.1/6431 Files in this item: 0
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Catanach, Therese A. (August 29, 2007)[more][less]
Abstract: Based on museum-held and field-collected specimens new data are presented regarding the distribution, adult phenology and first-instar larva of the uncommon green lacewing Abachrysa eureka. It was found that this species is broadly distributed across the southeastern United States, from Texas to the east coast south to Florida and north to South Carolina. There are multiple short duration emergence periods which vary with latitude. This species appears to be a typical chrysopid in various biological aspects, such as the occurrence of a stalked egg and placement of debris on the backs of larva. URI: http://handle.tamu.edu/1969.1/5709 Files in this item: 0
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Mohedas, Agustin (August 22, 2007)[more][less]
Abstract: Circumferential distension of the arterial wall during the cardiac cycle regulates endothelial cell (EC) morphology and function. We have previously shown that cyclic stretching of ECs leads to activation of signaling events relevant to atherosclerosis, but that this signaling subsides when the cells align perpendicular to stretch. We hypothesized that the purpose of this cellular response is to maintain a homeostatic stress level within the cell. Stresses within the cell are both born and created by cytoskeletal components. Stress fibers create tension that is transmitted to substratum via integrin connections. To test if this alignment response affects the forces applied to the substratum by stretching the ECs, we are developing a system to quantify substrate deformation caused by stretching ECs. The technique uses a poly(ethylene glycol) diacrylate hydrogel having an elastic modulus appropriate for traction microscopy and embedded with fluorescent beads. The traction microscopy system was comprised of computer controlled actuators and a clamping mechanism used to stretch the fluorescent bead embedded hydrogels under a confocal microscope objective. Image analysis via cross-correlation of bead displacements was used to generate the displacement field of the hydrogel immediately below and surrounding the cell. The preliminary results obtained indicate a successful proof of concept and show the method to be sound in principle. The system provides for the development of unique experimental conditions including the ability to perform uniaxial and biaxial stretching. In conclusion, the development of a novel method for the characterization of endothelial cell mechanics appears to be possible. However, the technique must be further developed and refined in order to increase efficacy and repeatability. URI: http://handle.tamu.edu/1969.1/5703 Files in this item: 0
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Population structure of the gray snapper, Lutjanus griseus, in the U.S. waters of the Gulf of MexicoEbelt, Nancy D (August 3, 2007)[more][less]
Abstract: Gray snapper, Lutjanus griseus, comprise an important recreational fishery in U.S waters of the Gulf of Mexico (hereafter Gulf). Currently, gray snapper in the Gulf are managed as a single stock; however, there are no data on the population structure of the species. Population structure of gray snapper in the Gulf was assessed via homogeneity testing of allele and genotype distributions at 13 nuclear-encoded microsatellites and a 590 base-pair fragment of mitochondrial DNA. No significant differences in allele or haplotype distributions of either microsatellite or mitochondrial DNA were found in samples from five localities in the Gulf and one locality from the western Atlantic. These data are consistent with a single-stock hypothesis for gray snapper in the Gulf. Levels of genetic variation were comparatively low and analysis of demographic history revealed a two to three order-of-magnitude decrease in effective population size occurring over the past 5,000 years. The low genetic variation combined with the significant decrease in effective population size is compatible with the hypothesis that colonization of the Gulf by gray snapper occurred following the reduction in effective size, and that there has been insufficient time for genetic divergence to occur. Although there was no evidence of multiple stocks, the low levels of genetic variation and decline in effective population size may have implications for management of the gray snapper resource. URI: http://handle.tamu.edu/1969.1/5701 Files in this item: 0
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Kolb, Frances Bailey (August 3, 2007)[more][less]
Abstract: This paper examines the influence of colonial policy and intercultural relations on the development of Acadian settlement in Louisiana between 1765 and 1785, spanning a portion of both French and Spanish colonial periods. Research has included an array of secondary sources, books, articles and maps, as well as a variety of primary sources, including published collections and archival material. Analysis of sources reveals two stages of Acadian settlement: the determination of physical location of settlements, and the characteristics, such as economic, demographic, and social, pertaining to the settlements. Political and social forces within colonial Louisiana affected the two stages of Acadian settlement differently. Colonial settlement and defense policies and Acadian culture influenced the location of settlements most strongly, while Acadian relations with other groups in Louisiana shaped the characteristics that the settlements developed during the 1770s. Acadian settlement indicates the imperial policies of France and Spain and the effect of these policies on the colonial population of Louisiana. URI: http://handle.tamu.edu/1969.1/5700 Files in this item: 0
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