Life Sciences Commons^™

Identification Of Inhibitors Of The Glutaminyl And Prolyl Trna Synthetases From Pseudomonas Aeruginosa, Yaritza Escamilla

Theses and Dissertations

Antibiotic resistance is a growing global threat and bacterial infections caused by antibiotic resistant bacteria have become increasingly difficult and expensive to treat with most current antibiotics. Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen and a leading cause of nosocomial infections and is the leading cause of mortality in cystic fibrosis patients. Aminoacyl-tRNA synthetases (aaRSs) are a class of enzymes that catalyze the covalent attachment of amino acids to their cognate tRNAs during protein biosynthesis. The glutaminyl- tRNA synthetase from P. aeruginosa was over-expressed, enzymatically characterized and developed into a screening platform for the discovery of chemical compounds that inhibit …

Applications Of Side Scan And Parametric Echosounders For Mapping Shallow Seagrass Habitats And Their Associated Organic Carbon, Austin L. Greene

Theses and Dissertations

Despite a global valuation of $1.9 trillion seagrass habitats world-wide are in decline—directly impacting the large soil carbon stocks associated with seagrasses. Many methods exist to measure the health of seagrass habitats, yet few apply to shallow coastal ecosystems. Those that do lack spatial resolution (satellite surveys) or do not provide continuous data across large areas (point-based surveys). Furthermore, carbon content of these ecosystems is largely limited to destructive and time-consuming soil core sampling. Side scan and parametric acoustics represent a unique technological opportunity to study habitat coverage and carbon content of vegetated coastal habitats (< 3 m depth). This study presents proof of concept for applications of recreational side scan and parametric sub-bottom profiling sonars in mapping both habitat coverage and organic carbon distribution in shallow seagrass habitats, and explores how these methods might be improved in future applications.

Interaction Graphs Derived From Activation Functions And Their Application To Gene Regulation, Simon Joyce

Graduate Dissertations and Theses

Interaction graphs are graphic representations of complex networks of mutually interacting components. Their main application is in the field of gene regulatory networks, where they are used to visualize how the expression levels of genes activate or inhibit the expression levels of other genes.

First we develop a natural transformation of activation functions and their derived interaction graphs, called conjugation, that is related to a natural transformation of signed digraphs called switching isomorphism. This is a useful tool for the analysis of interaction graphs used throughout the rest of the dissertation.

We then discuss the question of what restrictions, if …

Functional And Structural Characterization Of The Mevalonate Diphosphate Decarboxylase And The Isopentenyl Diphosphate Isomerase From Enterococcus Faecalis, Chun-Liang Chen

Open Access Dissertations

Enterococcus faecalis causes a diverse range of nosocomial infections (in wounds, the gastrointestinal tract, the blood stream and the endocardium), and multidrug-resistant strains have become a serious issue across countries. Vancomycin, a FDA-approved drug for the disruption of the bacterial cell wall biosynthesis, has been utilized to treat infectious diseases caused by Enterococci; however, the prevalence of vancomycin-resistant enterococci (VRE) threatens communities all over the world. We aim at developing novel therapeutic strategies to control bacterial growth of Enterococci, and we focus on targeting two essential enzymes involved in poly-isoprenoid biosynthesis in Enterococcus faecalis; one is the mevalonate diphosphate decarboxylase …

Synthesis And Performance Of Novel Supramolecular Tools For Single-Particle Cryogenic Electron Microscopy And Drug And Gene Delivery, Kyle J. Wright

Open Access Dissertations

High-resolution biomacromolecular structure elucidation is fundamentally important to structure-based drug design and basic research into complex biochemical processes. Cryo-EM is an emerging alternative to XRD and NMR that is complementary in many ways relative to XRD and NMR. Materials approaches to cryo-EM are anticipated to greatly facilitate the cryo-EM process, allowing progress toward a more high-throughput application of cryo-EM to address challenges in structural biology. ^ Various affinity-based approaches inspired by approaches previously introduced for 2D crystallization were developed for facilitation of cryo-EM. A library of affinity lipopolymer constructs were synthesized consisting of lipopolymers of various PEG molecular weights conjugated …

The Role Of Hif1alpha And Hif2alpha In Muscle Development And Satellite Cell Function, Shiqi Yang

Open Access Theses

Hypoxia inducible factors (HIFs) are central mediators of cellular responses to fluctuations of oxygen, an environmental regulator of stem cell activity. Muscle satellite cells are myogenic stem cells whose quiescence, activation, self-renewal and differentiation are influenced by microenvironment oxygen levels. However, the in vivo roles of HIFs in quiescent satellite cells and activated satellite cells (myoblasts) are poorly understood. Expression analyses indicate that HIF1α and HIF2α are preferentially expressed in pre- and post-differentiation myoblasts, respectively. Interestingly, double knockout of HIF1α and HIF2α (HIF1α/2α dKO) in embryonic myoblasts results in apparently normal muscle development and growth. However, HIF1α/2α dKO in postnatal …

The Effect Of Manganese (Mn) On Cell Proliferation And Migration In The Michigan Cancer Foundation-7 (Mcf-7) Human Breast Cancer Cell Line In Vitro, Justin Lloyd Wendel

Theses and Dissertations

Manganese (Mn) is a common environmental element necessary for mammalian physiological processes. However, dietary excess or deficiency can lead to detrimental health effects. Therefore, I investigated the effect Mn has on breast cancer progression in vitro. Utilizing MCF-7 breast cancer cells an MTT assay was performed to identify proliferative potential. After 5 days, results showed 100 nM manganese chloride (MnCl2) had a significant (p<0.01) increase in cell number over control. Using a scratch wound-healing assay, 100 nM MnCl2 was found to increase cellular motility as well as induce a possible change in morphology and cytoskeletal organization. Given Mn was shown to localize in the mitochondrial, we investigated Mn-induced ROS expression. 500 nM Mn significantly decreased (p<0.05) ROS levels. Collectively, I provide evidence that Mn may potentially drive less aggressive cancer cells towards a more invasive phenotype.

Mutlifunctional Platforms For Gene And Drug Delivery For Cancer Therapy, Jeffery J. Ambrose Jr.

Doctoral Dissertations

The National Cancer Institute and the American Cancer Society estimate that 1.6 million new cancer incidences and over half a million cancer related deaths occur annually [1][2]. Cancer the second most common cause of death in the United States [1], [2]. Although the causes of cancer can vary depending on cell type, all or almost all instances of cancer arise from a mutation or from an abnormal activation of the cellular genes that control cell growth and mitosis [3].

Treatment of a given cancer type depends on the subtype, stage and progression of the cancer. Varieties of cancer therapy include …

Validating Side Scan Sonar As A Fish Survey Tool, Michael A. Bollinger

Theses and Dissertations

Hydroacoustic methods can be used to answer a variety of questions regarding fish populations and behavior. In this study, side scan sonar methodology was developed to quantify abundance and biomass and compared to established visual observation methods on SCUBA over artificial reef structures in the western Gulf of Mexico. Side scan sonar methods were equivalent to SCUBA surveys for measuring fish abundance over the same reef areas, however, abundances were significantly higher when the larger area sampled by side scan was utilized. Side scan sonar methods were also more time efficient than SCUBA, ROV and long line fishing methods (66.7%, …

Dlipin-A Link Between Lipid Metabolism, Glucose Homeostasis And Growth In Drosophila Melanogaster, Sandra Schmitt

Graduate Theses and Dissertations

Lipins are a family of highly conserved proteins found from yeasts to humans. Lipins have dual functions, serving as phosphatidate phosphatase enzymes (PAP) in the synthesis of neutral fats (triacylglycerols, TAG) and as transcriptional co-regulators that affect the expression of genes involved in lipid and fatty acid metabolism. Thus, they play central roles in metabolic control. Disruption of Lipin function has been implicated in lipodystrophy, obesity and insulin resistance. Using dLipin, the Drosophila homolog of Lipin, as a model, I aimed to elucidate the relationship between the two biochemical functions of Lipin and metabolic homeostasis. I discovered there is a …

Characterization Of Caxck31, A Bacterial Calcium/Proton Antiporter, Marc Robert Ridilla

Open Access Dissertations

To better understand a class of transporters known as Calcium/Cation Antiporters (CaCAs), the bacterial calcium/proton antiporter CAXCK31 was purified and characterized. New methods were developed for its heterologous overexpression and purification. These methods help to define stress responses to toxic membrane overproduction in E. coli and may be broadly applicable to studies of membrane proteins. The results from a variety of biochemical and biophysical experiments demonstrated that CAXCK31 exists as a dimer in the membrane and can be purified in the dimeric state. The methods used include chemical cross-linking, FRET, and SEC-MALS. In addition, various transport properties of CAXCK31, including …

A Comprehensive Uncertainty Analysis And Method Of Geometric Calibration For A Circular Scanning Airborne Lidar, Michael Oliver Gonsalves

Dissertations

This dissertation describes an automated technique for ascertaining the values of the geometric calibration parameters of an airborne lidar. A least squares approach is employed that adjusts the point cloud to a single planar surface which could be either a narrow airport runway or a dynamic sea surface. Going beyond the customary three boresight angles, the proposed adjustment can determine up to eleven calibration parameters to a precision that renders a negligible contribution to the point cloud’s positional uncertainty.

Presently under development is the Coastal Zone Mapping and Imaging Lidar (CZMIL), which, unlike most contemporary systems that use oscillating mirrors …

Folate Receptor-Targeted Delivery Of Small Interfering Rna To Cancer Cells, Yilin Zhang

Dissertations

The vitamin folic acid (folate, FA) has been extensively explored as a targeting ligand to deliver a variety of diagnostic/prognostic/therapeutic agents into various tumors through the assistance of its receptor – the folate receptor (FR). FR is over-expressed in many types of human cancer and can mediate internalization of FA-conjugates through an endocytic pathway. The discovery of small interfering RNA (siRNA), which is cable of inducing potent gene silencing in a sequence-specific manner, provides an excellent molecular tool to suppress aberrant gene expression in malignancies, and therefore siRNA has the potential to revolutionize cancer therapeutics. Towards the goal of developing …

Ethnobotanical History And Seed Oil Chemistry Of The Physic Nut, Jatropha Curcas, Nathan M. Leclear

Theses and Dissertations - UTB/UTPA

Jatropha curcas L., Euphorbiaceae, is a small tree native to the neotropics. Despite renewed economic interests in Physic Nut, mainly for biodiesel production, a comprehensive analysis of the ethnobotanical history of J. curcas is lacking. An account of the pre-Columbian neotropical distribution of this species and its historical uses are presented. Using capillary gas chromatography, studies were conducted to quantify the natural variation in seed oil content and fatty acid composition of the seed oil from several species of Jatropha, including assessment of how these parameters change during seed maturation. Natural variation in seed oil content was detected (F7,93 = …

Effect Of Myristicin, A Constituent Of Parsley, On Levels Of Glutathione And Glutathione S-Transferase In Mice Tissues, Maria Theresa Tijerina

Theses and Dissertations - UTB/UTPA

Glutathione (GSH) and related enzymes interact as a ubiquitous and efficient detoxification system in biological organisms. Several naturally occurring, as well as synthetic compounds, are known to increase the levels of glutathione/glutathione S-transferases (GST). One of the natural compounds includes myristicin, which is a constituent of parsley leaf oil as well as other natural foods. The extent to which the levels of the GSH/GST system can be induced appears to be dependent on the specific tissue type and the amount of myristicin administered. Our results show that increased amounts of myristicin exhibited beneficial effects within a certain range for each …