Life Sciences Commons^™

The Role Of Human Endogenous Retroviruses In Renal Cell Carcinoma, Michele D. Tisdale

Biological Sciences Theses & Dissertations

Human endogenous retroviruses make up approximately 8-9% of the human genome. A number of expressed HERVs, those that are actively transcribing, have been associated with various cancers. Suppression mechanisms that control HERV expression often fail or become more permissive in tissues where expression should be restricted. Previous studies have identified HERV expression in breast cancer tissues, whereas normal tissue HERV expression remained suppressed. In addition, studies of DNA hypermethylation have correlated with the ability to contribute to cancer development. Hypermethylation of several tumor suppressor genes occurs frequently in cancers and alterations in promoter regions could contribute to the development of …

Changing Fecundity And Reproductive Output In Females Of A Chesapeake Bay Population Of Blue Crab, Callinectes Sapidus, Shannon L. Wells

OES Theses and Dissertations

The Chesapeake Bay blue crab, Callinectes sapidus, is an important species both ecologically and as a fishery. Fishery dependent and independent data indicate that the population declined abruptly in the mid-1990s and has remained low. Previous work prior to the decline in population abundance found a significant relationship between size and fecundity for mature females. As with many heavily fished populations, this population has experienced a reduction in the size at maturity. The objectives of this study were to reassess the fecundity of the population, determine the lipid and protein energy allocated for reproduction, and to examine the concentrations …

Inhibition Of Yeast Hexokinase By The Antimalarial Drug Artemisinin: Probing Mechanism Of Action With A Model Enzyme, Jennifer S. Spence

Biological Sciences Theses & Dissertations

A leading infectious cause of death, malaria threatens approximately half of the world's population, and drug-resistant strains of Plasmodium falciparum have created immense difficulty in chemotherapy of the disease. The artemisinin (ART) class of antimalarials may represent a powerful solution. In addition to their safety, effectiveness, and moderate cost, they are the only drugs in use for which there has been no widespread evidence of clinical resistance. The exact parasiticidal mechanism of ART is highly contested, but evidence suggests that protein alkylation may play a role in cytotoxicity. in vitro essays were performed using yeast hexokinase (HK) to demonstrate a …

Effect Of The Herbivorous Channel Clinging Crab (Mithrax Spinosissimus) On Patch Reef Algal Communities In The Florida Keys, Florida (Usa), Angela M. Mojica Osorio

Biological Sciences Theses & Dissertations

Coral reefs worldwide are undergoing dramatic habitat modification from coral to macroalgal dominance due to water pollution, coral diseases, global. warming, and the loss of herbivores. This phase-shift bas been particularly severe on Caribbean reefs due in large measure to the decline of piscine and echinoderm grazers, whose presence appears crucial for stemming the decline of coral reefs and enhancing their resilience. Virtually unknown, however, is the role of other macrograzers in coral reef ecosystems. This is the first study to examine the feeding ecology and grazer effect of the herbivorous West Indian spider crab (Mithrax spinosissimus) on inshore patch …

Prostate Cancer Biomarker Identification: A Comparative Study, Wenjuan Jiang

Computational Modeling & Simulation Engineering Theses & Dissertations

With the current development of proteomics techniques, the discovery of potential molecular biomarkers for early detection of prostate cancer has been greatly improved. In this thesis, we implemented five classifiers including the support vector machine (SVM), Bayesian Classifier, Decision Tree, Random Forest and the Multilayer perceptron (MLP) to test their effectiveness in prostate cancer biomarker identification using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) tissue imaging data. The classifiers were utilized to discriminate cancer mass spectra from normal ones for the data collected at the Eastern Virginia Medical School (EVMS). There are 94 7 spectra from normal tissues and 27 from …

Lipid Targets Of The Antimalarial Trioxanes In Plasmodium Falciparum, Carmony Leah Hartwig

Biological Sciences Theses & Dissertations

Malaria is among the most debilitating diseases of man. The protozoan parasite, Plasmodium falciparum, causes over a million annual fatalities. The antimalarial trioxanes, exemplified by artemisinin, are among the few pharmaceuticals for which clinical resistance has not become widespread. Artemisinin is a naturally occurring sesquiterpene lactone, containing a unique endoperoxide pharmacophore. Despite extensive study, the precise antimalarial mechanism of action of trioxanes remains elusive. Heme iron-mediated cleavage of the endoperoxide within the parasite digestive vacuole is hypothesized to generate cytotoxic metabolites capable of alkylating heme and damaging cellular macromolecules. The hypothesis of this research is that the endoperoxide pharmacophore …

Biotic And Abiotic Characteristics Influencing Nest Location And Trophic Relationships Of The Fungus-Growing Ant Trachymyrmex Septentrionalis (Formicidae: Attini), Jonathan Paul Howell

Biological Sciences Theses & Dissertations

Trachymyrmex septentrionalis represents the only species of fungus-growing ant in the southeastern United States. T. septentrionalis cultivates a symbiotic fungus on which the ants feed. Worker ants collect plant and animal debris to feed the fungus. These ants are common in Florida, but increasingly scarce as they near the northern extent of their range in New Jersey. Colonies of T. septentrionalis occur in patches throughout Blackwater Ecological Preserve, a longleaf pine forest in southeastern Virginia. Blackwater Ecologic Preserve is a 129 hectare tract of land, located in Isle of Wight county, that is undergoing a regimen of controlled burning to …

Mechanisms Of Regulation Of Proximal Tubule Sodium Transporters In Obesity-Induced Hypertension, Marta A. Ambrozewicz

Theses and Dissertations in Biomedical Sciences

Hypertension is one of the common complications of obesity. Using a rat model of diet induced obesity and hypertension we investigated some of the mechanisms that are involved in regulation of blood pressure in obesity. The first aim of this study was to determine the role of proximal tubule transporters on the renal sodium handling in obese hypertensive (OP) and lean normotensive (OR) rats. An acute increase in renal perfusion pressure resulted in a blunted natriuretic response in OP vs. OR rats and indicated that increased sodium reabsorption in the proximal tubule is casual, at least in part, for hypertension …

Phosphorylation Of The Estrogen Receptor Alpha (Erα) At Serine 118 By Phospho-P44/42 Mapk And Regulation By Estrogen And Progesterone In Human Uterine Leiomyoma Tissue And Cells, Tonia Lakisha Hermon

Theses and Dissertations in Biomedical Sciences

It is thought that the growth of uterine leiomyomas may be mediated by the interaction of estrogen receptor alpha (ERα) and growth factor pathways and that phosphorylation of ERα at serine 118 (ERα-phospho-Ser118) is important in this interaction. In tissue, immunoblotting and immunohistochemistry were used to investigate the expression of ERα-phospho-Ser118, phosphorylated p44/42 mitogen-activated protein kinase (phospho-p44/42 MAPK), and proliferating cell nuclear antigen (PCNA) in human leiomyoma and myometrial tissues during the proliferative and secretory phases of the menstrual cycle. In vitro studies to assess proliferation of uterine leiomyoma (UtLM) and uterine smooth muscle (UtSMC) cells and expression of ERα-phospho-Ser118 …

Role Of The Human Cytomegalovirus Ie2 Protein On Transcriptional Regulation Of Viral Promoters, Siabhon Michelle Harris

Theses and Dissertations in Biomedical Sciences

Human cytomegalovirus (HCMV) is a ubiquitous pathogen able to cause severe mortality and morbidity in immuno-compromised individuals. Successful infection by HCMV is dependent on expression of viral genes essential for replication. Immediate early (IE) gene products are the first subset of viral genes to be expressed during infection and function as key transcriptional regulators. IE2 is one the most predominantly expressed IE proteins and is essential for HCMV infection. IE2 transactivates several viral promoters, including those of the essential viral DNA polymerase (UL54) and UL112-113 gene regions. IE2 is also able to autoregulate is own expression and repress expression of …

Effects Of Hze Irradiation On Chemical Neurotransmission In Rodent Hippocampus, Mayumi Machida

Theses and Dissertations in Biomedical Sciences

Space radiation represents a significant risk to the CNS (central nervous system) during space missions. Most harmful are the HZE (high mass, highly charged (Z), high energy) particles, e.g. ⁵⁶Fe, which possess high ionizing ability, dense energy deposition pattern, and high penetrance.

Accumulating evidence suggests that radiation has significant impact on cognitive functions. In ground-base experiments, HZE radiation induces pronounced deficits in hippocampus dependent learning and memory in rodents. However, the mechanisms underlying these impairments are mostly unknown.

Exposure to HZE radiation elevates the level of oxidation, resulting in cell loss, tissue damage and functional deficits through direct ionization …

A Bio-Optical Model For Syringodium Filiforme Canopies, Margaret A. Stoughton

OES Theses and Dissertations

Seagrasses are significant ecological and biogeochemical agents in shallow water ecosystems throughout the world. In many regions, seagrass meadows occupy a sufficient fraction of the coastal zone, and generate optical signatures that can be observed from space. Bio-optical models of light absorption and scattering by submerged plant canopies for certain species such as Thalassia testudinum and Zostera marina have successfully modeled the plane irradiance distribution and photosynthesis within the submerged canopies. Syringodium filiforme differs &om T. testudinttm and Z marina, in leaf morphology and canopy architecture. The objective of this study was to develop a radiative transfer model that …

Characterization Of Antibiotic Resistance In Vibrio Cholerae Isolated From Ships' Ballast And Other Environmental Sources, Frank Kornegay Thomson Iii

OES Theses and Dissertations

Ships' ballast has been implicated as a vector in the dispersal of invasive species into new environments. Numerous cases have been documented for the introduction of macroorganisms via ballasting operations, but what is less known is the role of ballast water and residuals in the spread of potentially harmful microbes, especially with reference to novel genotypes. Of particular interest are the genes encoding for various forms of antibiotic resistance, many of which are carried on mobile genetic elements. A four-year sampling effort has yielded over 300 putative isolates of Vibrio cholerae from ships' ballast tanks and various environmental sources, of …

Study Of The Dna Damage Complexes Within The Htlv-1 Tax Oncoprotein Interactome, Sidi Mehdi Belgnaoui

Theses and Dissertations in Biomedical Sciences

Human T-cell leukemia virus type 1 (HTLV-1) is a transforming retrovirus that can give rise to adult T-cell leukemia (ATL) and HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP). Tax is a virally encoded oncoprotein that is involved in HTLV-1 mediated cellular transformation. It has been hypothesized that Tax induces genomic instability via repression of the cellular DNA damage repair response. Our laboratory has previously shown that the interaction between Tax and various proteins involved in the DNA-damage response pathway impairs the ability of these proteins to mount an efficient repair response. As part of these observations, we proposed that Tax induces …

Interdependent Regulation Of Cytomegalovirus Proteins In Complex, Lisa L. Bolin

Theses and Dissertations in Biomedical Sciences

Human cytomegalovirus (HCMV) is a ubiquitous herpesvirus that causes significant morbidity and mortality in the immune compromised. Using the mutine cytomegalovirus (MCMV) model, we identified two genes, M140 and M141, which are determinants of macrophage tropism. Monocytes/macrophages are a critical cell type for cytomegalovirus (CMV) pathogenesis as sites of viral latency and by supporting viral replication and disseminating virus throughout the body. We previously found that the localization of the M140/M141 gene products (pM140/pM141) is different when the proteins are co-expressed as compared to their individual expression. When the proteins are individually expressed pM141 localizes diffusely throughout the cytoplasm and, …

Comparison Of Immune Correlates, Age Related Changes And Proteomic Profiling Of Healthy Individuals Receiving Influenza Vaccines, Gaurav Basu

Theses and Dissertations in Biomedical Sciences

The burden of influenza related infections is substantial, both in terms of illness, lives lost and economic impact on society. The degree of impact of influenza related infections is much higher in the elderly population where it is a leading cause of catastrophic disability; greatly affecting the quality of life of elderly persons above 65 years of age. Vaccination is the mainstay for control and prevention of influenza infections. There are two vaccine formulations that are licensed for use at present. The inactivated influenza vaccines (TIIV) which have been used for 60 years in all age groups and the new …

Factors Affecting Adult Foraging And Chick Growth Of Adélie Penguins (Pygoscelis Adeliae) Off The Western Antarctic Peninsula: A Modeling Study, Erik W. Chapman

OES Theses and Dissertations

Coupled individual-based models that simulate Adélie penguin ( Pygoscelis adeliae) chick growth and adult foraging behavior during the chick growth period were developed and used to explore factors that influence chick fledging mass and adult foraging energetics off the western Antarctic Peninsula (WAP). Adélie penguin colonies in this region are undergoing changes in population size that have been correlated with climate-driven alteration of the marine and terrestrial environment. Simulations were selected to highlight possible mechanistic linkages between climate variability and chick growth and adult foraging processes. These processes were the focus of this study because chicks that fledge at …

Molecular Dynamics Study Of Single Stranded Peptide Nucleic Acids, Anna K. Manukyan

Theses and Dissertations in Biomedical Sciences

A PNA molecule is a DNA strand where the sugar-phosphate backbone has been replaced by a structurally homomorphous pseudopeptide chain consisting of N(2-aminoethyl)-glycine units. PNA binds strongly to both DNA and RNA. However, an analysis of the X-ray and NMR data show that the dihedral angles of PNA/DNA or PNA/DNA complexes are very different from those of DNA:DNA or RNA:RNA complexes. In addition, the PNA strand is very flexible. One way to improve the binding affinity of PNA for DNA/RNA is to design a more pre-organized PNA structure. An effective way to rigidify the PNA strand is to introduce …

Ecology And Molecular Phylogenetics Of Hydnora (Hydnoraceae) In Southern Africa, Jay Francis Bolin

Biological Sciences Theses & Dissertations

The Hydnoraceae are a clade of root holoparasitic angiosperms that contain two small genera, Hydnora and Prosopanche. This study, focused on Hydnora, presents novel data regarding the pollination biology, germination ecology, parasite-host nutritional relationships, and the molecular systematics of this group. Experimental addition of the primary pollinator, Dermestes maculatus to Hydnora africana chamber flowers demonstrated beetle imprisonment during the carpellate stage. Changes in the inner surfaces of the androecial chamber allowed beetle escape after pollen release. Most beetles escaped, dusted with viable pollen, three days after pollen release. To investigate germination ecology, aqueous root extracts of host and …

Ecology Of Neotropical Arboreal Snakes And Behavior Of New World Mollusk-Eating Snakes, Julie M. Ray

Biological Sciences Theses & Dissertations

The Neotropics is a biologically diverse region that provides man opportunities for ecological and behavioral studies. I utilized the speciose ophidian fauna of central Panama to explore the general ecology of arboreal snakes, the defensive behaviors of the snake community, and the diet of mollusk-eating snakes. I studied arboreal species to understand interspecilic relationships in several morphometric characters and to examine preferences in habitat. There were significant morphometric differences in relative length of jaw, mass, tail length, and size at midbody. The arboreal realm was partitioned among species by distance to ground, distance to water, and diameter of the perch. …

Analysis Of N-Linked Oligosaccharides Of Prostate-Specific Antigen And Prostatic Acid Phosphatase In Prostatic Fluids, Krista Yaudes White

Theses and Dissertations in Biomedical Sciences

Presently, prostate cancer is the most common cancer afflicting men in the United States, with serum PSA being the "gold standard" protein biomarker used in the clinic for detecting and diagnosing prostate cancer. Nonetheless, serum PSA levels can also be elevated in non-cancerous conditions as well, such as benign prostatic hyperplasia (BPH). Due to this overlap, many unnecessary biopsies and radical prostatectomies occur, leading to patient distress. Despite recent advances to clinical assays which consider other clinical parameters, there is still a great need for improved clinical detection methodologies for prostate cancer, including improved biomarkers. Therefore, this research project aims …

Computational Studies On R67 Dihydrofolate Reductase: An Investigation Into Its Unique Binding Patterns, Chuanyin Shi

Theses and Dissertations in Biomedical Sciences

R67 dihydrofolate reductase (R67 DHFR) is a plasmid encoded enzyme which catalyzes the reduction of dihydrofolate (DHF) to tetrahydrofolate (THF) using NADPH as a cofactor. R67 DHFR is a homo-tetramer and D2 symmetric. It contains only one active site, which spans the central channel of the enzyme. The active site can bind either two reactants (DHF), two cofactors (NADPH) or one of each (NADPH/DHF), which is the productive ternary complex (i.e. the complex which yields product). In order to favor formation of the productive complex, this enzyme exhibits binding cooperativity. Unlike other allosteric enzymes which achieve binding cooperativity through conformational …