Biology Commons^™

Floral Symmetry Genes Elucidate The Development And Evolution Of Oil-Bee Pollinated Flowers Of Malpighiaceae And Krameriaceae, Farahnoz N. Khojayori

Theses and Dissertations

Specialization on insect and animal pollinators is thought to be the driving force for the evolution of floral traits. Specifically in the New World (NW), the oil-bee pollination syndrome has led to the convergence of floral characters in two distantly related families of core eudicots, Malpighiaceae and Krameriaceae. Both families display a flag-like structure that establishes a zygomorphic flower and floral oil rewards in epithelial elaiophores. These traits work concomitantly to attract and reward female oil-bees that help fertilize these flowers and in return receive oils. The underlying genetics of floral zygomorphy were studied in several clades of core eudicots, …

Exogenous Fniii 12-14 Regulates Tgf-Β1-Induced Markers, Hilmi M. Humeid

Theses and Dissertations

The extracellular matrix protein Fibronectin (FN) plays an important role in cell contractility, differentiation, growth, adhesion, and migration. The 12th -14th Type III repeats of FN (FNIII 12-14), also referred to as the Heparin-II domain, comprise a highly promiscuous growth factor (GF) binding region. This binding domain aids in cellular signaling initiated from the ECM. Additionally, FN has the ability to assemble into fibrils under certain conditions, mostly observed during cell contractile processes such as those that initiate due to upregulation of Transforming Growth Factor Beta 1 (TGF-β1) [1], [2]. Previous work from our lab has shown that self-assembly of …

A Bronchiolitis Study: The Overuse Of Bronchiolitis Therapies In Children Admitted Into The Hospital, Jocelyn S. Canedo

Theses and Dissertations

Bronchiolitis is prevalent among infants of 0 to 12 months, and usually caused by a variation of viruses. Signs and symptoms consist of coughing, rapid breathing, and an occasional fever in some infants. Bronchiolitis is not treated with antibiotics, but rather with proper medical examination and other procedures. Chest radiographs, steroids, and certain bronchodilators are considered ineffective treatments. This study identified the amount of ineffective procedures being used in infants admitted into the pediatric emergency room, and the effect it had on the patient’s average hospital stay. Past medical records were used in this clinical study. Statistical analyses and graphs …

Linking Physiology, Temperature, And Recruitment: A Classic Competitive Story Rewritten By Climate, Maeve Kerrigan Snyder

Theses and Dissertations

Climatic changes have the potential to alter population and community dynamics, ultimately influencing the biogeographic distributions of species. For many organisms, reproduction is physiologically tied to temperature. We tested the hypothesis that a physiological mechanism for reproductive failure in the acorn barnacle, Semibalanus balanoides, would result in predictable patterns of larval recruitment over broad geographic scales. Recruitment density was predicted to be dependent on the duration of permissive temperatures (< 10oC). for successful reproduction in adult populations of S. balanoides. We found that temperature was a reliable predictive variable for recruitment densities throughout our study region. Post-recruitment processes were also considered, specifically the competition between Semibalanus balanoides and Chthamalus montagui, described in Joseph Connell’s 1961 experiment. The competitive hierarchy outlined in this experiment is not consistently observed throughout the range overlap of the two species. Growth and mortality were found to differ dependent on species and latitude, indicating that climate mediates this classic ecological system. Our results provide useful knowledge for refining models of biogeographic shifts. A consistent failure of larval supply and a breakdown of competitive advantage could accelerate the pace of predicted range contraction for S. balanoides. Further investigation of how environmental variables interact with physiology and ecological processes is necessary for accurate predictions of climate change effects

Interactive Effects Of Domoic Acid Allelopathy, Salinity, And Eutrophication On Estuarine Phytoplankton Community Structure, Elise Van Meerssche

Theses and Dissertations

Coastal regions and estuaries are particularly sensitive to the increase in nutrient loading and river runoff, threatening the ecosystems with possible spreads in harmful algal blooms (HABs). As an example, blooms of toxic Pseudo-nitzschia species can release acute concentrations of the neurotoxin domoic acid (DA) in the water column. When ingested at concentrations higher than 20 ppm, DA can cause the death of marine birds, marine mammals and even humans. The main objectives of my research were to determine the drivers of Pseudo-nitzschia abundance and toxicity and to assess how these drivers influenced the phytoplankton community structure and DA allelopathy. …

Migratory Patterns And Population Genetic Structure In A Declining Wetland-Dependent Songbird, Matthew G. Desaix

Theses and Dissertations

Understanding migratory connectivity is essential for assessing the drivers behind population dynamics and for implementing effective management in migratory species. Genetic markers provide a means to describe migratory connectivity, as well as incorporate population genetic analyses, however genetic markers can be uninformative for species with weak genetic structure. In this study, we evaluate range-wide population genetic structure and migratory connectivity in the prothonotary warbler, Protonotaria citrea, a wetland-dependent neotropical migratory songbird, using high-resolution genetic markers. We reveal regional genetic structure between sampling sites in the Mississippi River Valley and the Atlantic Seaboard with overall weak genetic differentiation among populations …

Novel Insights Into The Contribution Of Cellular Senescence To Cancer Therapy: Reversibility, Dormancy And Senolysis., Tareq Saleh

Theses and Dissertations

Cellular senescence a specialized form of growth arrest that contributes to the pathogenesis of several aging-related disorders including cancer. While by definition tumor cells are considered immortalized, they can undergo senescence when exposed to conventional and targeted cancer therapy. Therapy-Induced Senescence (TIS) represents a fundamental response to therapy and impacts its outcomes. However, TIS has been considered a positive therapeutic goal since senescent tumor cells are expected to enter a state of permanent growth abrogation. In this work we examined the hypothesis that a subpopulation of senescent cells can re-acquire proliferative potential after a state of senescent dormancy, indicating that …

Effects Of Diabetes On Ovarian Cancer: Data Analysis And Modeling Study, Claire Belay

Theses and Dissertations

Ovarian cancer has one of the highest mortality rates of all gynecological cancers [13]. Further knowledge of risk factors for the growth of ovarian tumors would be beneficial in both the treatment and prevention of this type of cancer. Previous research has shown a positive correlation between diabetes and prostate tumor growth [22], The first aim of this study was to determine the effect of diabetes of ovarian tumor growth. The second aim was to develop a model to predict ovarian tumor growth based on the microenvironment within a patient’s body. The hypothesis was that there would be a positive …

Natural And Anthropogenic Drivers Of Tree Evolutionary Dynamics, Brandon M. Lind

Theses and Dissertations

Species of trees inhabit diverse and heterogeneous environments, and often play important ecological roles in such communities. As a result of their vast ecological breadth, trees have become adapted to various environmental pressures. In this dissertation I examine various environmental factors that drive evolutionary dynamics in threePinusspecies in California and Nevada, USA. In chapter two, I assess the role of management influence of thinning, fire, and their interaction on fine-scale gene flow within fire-suppressed populations of Pinus lambertiana, a historically dominant and ecologically important member of mixed-conifer forests of the Sierra Nevada, California. Here, I find evidence …

Patterns Of Molecular Population Genetic And Phenotypic Variation Associated With Urbanization In The Western Black Widow Spider, Lindsay Miles

Theses and Dissertations

In urban population genetic studies, the "urban fragmentation model" predicts that urbanization acts as a barrier that isolates native populations, and can lead to reduced gene flow and increased genetic drift between populations. The “urban facilitation model” predicts urban areas act as corridors to increase dispersal among urban areas, and can lead to higher genetic diversity within and lower differentiation between urban areas.

In a review of the current literature, we found that there is no consistent signature of reduced within-population genetic diversity or increased between-population genetic differentiation. Analyses that investigate the urban barriers to gene flow also found no …

Evaluation And Adaptation Of Live-Cell Interferometry For Applications In Basic, Translational, And Clinical Research, Kevin A. Leslie

Theses and Dissertations

Cell mass is an important indicator of cell health and status. A diverse set of techniques have been developed to precisely measure the masses of single cells, with varying degrees of technical complexity and throughput. Here, the development of a non-invasive, label-free optical technique, termed Live-Cell Interferometry (LCI), is described. Several applications are presented, including an evaluation of LCI’s utility for assessing drug response heterogeneity in patient-derived melanoma lines and the measurement of CD3+ T cell kinetics during hematopoietic stem cell transplantation. The characterization of mast cells during degranulation, the measurement of viral reactivation kinetics in Kaposi’s Sarcoma, and drug …

Genetic Diversity Of Kemp's Ridley (Lepidochelys Kempii) Sea Turtles On South Padre Island, Texas, Hilary R. Frandsen

Theses and Dissertations

In 2010, researchers observed an abrupt decline in nesting numbers of the Kemp’s ridley following 35 years of positive growth. In wake of this halt, and subsequent lowered nesting averages, evaluation of the genetic diversity of remaining individuals is relevant to investigate the plausibility of a genetic bottleneck, and determine the reproductive stability of the Kemp’s ridley.

Here, I evaluate the genetic diversity within a sampling of the Kemp’s ridleys on South Padre Island using two methods: targeting the mitochondrial control region and targeting the complete mitochondrial genome. Opportunistic samples were donated from juvenile ridleys on the East coast, and …

Foxo3 Regulation Of Stem Cell Markers Oct4 And Sox2 In Pten-Null Glioblastomas, Eduardo Martinez

Theses and Dissertations

The PI3K pathway controls many cellular processes such as cell growth, survival, metabolism, apoptosis, and differentiation. Canonically, PI3K activates AKT leading to subsequent nuclear exportation of FOXO transcription factors. Dysregulation of the PI3K pathway is a hallmark in many cancers and often is attributable to a null mutation in PTEN. PTEN is a phosphatase that reverses the reactions catalyzed by PI3K. Loss of PTEN leads to constitutive inactivation of tumor suppressor FOXO proteins. However, there is increasing evidence that FOXO may still reside and promote transcriptional activity in the nucleus despite high PI3K output within certain advance cancers and …

Phylogeography Of An Estuarian Calanoid Copepod; Acartia Tonsa In The Texas Gulf Of Mexico, Nicole J. Figueroa

Theses and Dissertations

The calanoid copepod, Acartia tonsa is one of the most abundant and well-studied estuarian species. However, the idea that this cosmopolitan species has unrestricted dispersal and high gene flow has been challenged. In this study, a more holistic picture of the phylogeography of A. tonsa was developed using the mitochondrial gene cytochrome oxidase one (mtCOI). Multiple new lineages were found in the Texas Gulf of Mexico that are basal to Northeastern Atlantic lineages. Connectivity was also observed between Brazil and the Texas Gulf of Mexico. The revised phylogeny shows a clear pattern of cryptic speciation as the species made a …

Understanding Community And Ecophysiology Of Plant Species On The Colorado Plateau, Hannah Elizabeth Yokum

Theses and Dissertations

The intensification of aridity due to anthropogenic climate change is likely to have a large impact on the growth and survival of plant species in the southwestern U.S. where species are already vulnerable to high temperatures and limited precipitation. Global climate change impacts plants through a rising temperature effect, CO2 effect, and land management. In order to forecast the impacts of global climate change, it is necessary to know the current conditions and create a baseline for future comparisons and to understand the factors and players that will affect what happens in the future. The objective of Chapter 1 is …

Utilizing Accelerometer Telemetry Tags To Compare Red Snapper (Lutjanus Campechanus) Behavior On Artificial And Natural Reefs, Ethan T. Getz

Theses and Dissertations

The Texas Parks and Wildlife Department Artificial Reef Program has deployed over 2,800 hectares of reefing area composed of petroleum platforms, steel vessels, and concrete. Artificial reefs have been shown to support many important reef fishes such as red snapper (Lutjanus campechanus), however, few studies have compared fish behavior on artificial reefs and natural habitats. We examined activity levels, behavioral patterns and habitat preferences of red snapper over natural reefs, oil platforms and submerged ships. Telemetry tags (Sonotronics model MTT) with tri-axial acceleration range, average depth, and average temperature were programmed to optimize data collection and tag life. …

Predatory Capacity Of King Crabs In Antarctica, Brittan V. Steffel

Theses and Dissertations

For millions of years, cold water temperatures have excluded shell-crushing (durophagous) predators from continental-shelf environments off the western Antarctic Peninsula. Recently, however, king crabs, Paralomis birsteini, have been found in dense, reproductively viable populations on the upper continental slope, and rapid warming might enable them to expand to the shelf. King crabs are crushing shelled invertebrates on the slope, but calcification of sturdy, shell-crushing chelae is likely inhibited by the low saturation state of high-Mg calcite in the deep Southern Ocean. The objectives of this study were to better understand the predatory capacity of P. birsteini by estimating the potential …

Age And Growth Of Bonefish, Albula Species Among Cuban Habitats, Jacob Joseph Rennert

Theses and Dissertations

Bonefish (Albula spp.) are a prized sportfish among avid anglers worldwide. Two morphologically indistinguishable species of bonefish (Albula vulpes and Albula goreensis) exist in the circumtropical waters of the western Atlantic. A. vulpes grows faster and reaches larger sizes in the Florida Keys than in the Bahamas and other insular regions, but the mechanisms driving this variation have not been identified. Cuba supports large populations of bonefish, but their age, growth rate, and reproductive biology has not previously been examined. I obtained specimens from fish markets and local research staff in 3 regions around the periphery of Cuba from November …

Encapsulation Of Inositol Hexakisphosphate To Facilitate Cellular Entry And Programmed Cell Death In Breast Cancer Cells, Ilham Hassoon Kadhim

Theses and Dissertations

There are more than 60 isoforms of InsPs generated by phosphorylation and de-phosphorylation of inositol 1, 4, 5-trisphosphate (InsP3), a key cell-signaling molecule produced during G-protein-coupled receptor activation. Among InsPs, inositol hexakisphosphate (InsP6), also known as phytic acid (IP6), is the most abundant InsPs present in most cells. It plays a critical role in cellular differentiation, cell proliferation and apoptosis involving the PI3K/Akt signaling pathway. Several lines of studies have indicated the inhibitory activity of InsP6 in human and animal cancer cells via the inhibition of PI3K/Akt pathway. Increasing cellular contents of InsP6 is likely to inhibit cell proliferation and …

Modeling The Niche Space Of Coral Assemblages Along The Florida Reef Tract, Kelly Renee Mccaffrey

Theses and Dissertations

Quantifying the niche space of organisms is critical for conservation and restoration purposes. Yet, with warming oceans, we cannot assume that the localities that were optimal for species in the past remain so today or will be optimal for that species in the future. Over the next century, the climate is predicted to drive sea-surface temperatures to even higher levels, consequently increasing the risk of mass coral bleaching and disease outbreaks, and potentially reducing the niche space available to corals. Yet, there is considerable temporal and spatial variation in coral bleaching, disease prevalence, and mortality. Using data collected from 2398 …

Chlamydomonas Reinhardtii, A Model For Quorum Sensing At The Interkingdom Interface, Timothy Charles Haire

Theses and Dissertations

Microbial communities significantly impact the processes of the eukaryotic hosts they colonize. In many cases, symbiotic organisms both pathogenic and mutualistic coordinate their efforts through a process called quorum sensing (QS). QS is driven by low-molecular weight signals that regulate gene expression at threshold inducer concentrations, allowing phenotypic switching to be driven by cell density. These quorum sensing signals are subject to eukaryotic perception, and quorum associated phenotypes can directly influence the growth and development of eukaryotes. Eukaryotic perception of quorum sensing signals has been chiefly studied in plants, and to a lesser extent mammalian systems, yet no delineated model …

Response To Drought Of A Stream Fish Assemblage In A High Elevation Stream In The Intermountain West, Richard M. Simkins

Theses and Dissertations

One of the most influential disturbances for stream fish assemblages is large-scale declines in flow caused by periods of drought. Although stream characteristics are known to influence the response of stream fishes to drought, we asked if ecological traits of stream fishes determine, in part, their population level response to drought. To test for ecological trait-based responses to drought in a stream fish assemblage, we quantified species abundances over a period of 5 years that represented a wet to dry period. We sampled stream fishes in Yellow Creek, Wyoming, USA, a high elevation stream dependent on snow-storage for most of …

Role Of Terrestrial Organic Matter In Food Webs Of The Rocky Intertidal Zone, Douglas O. Fairbanks

Theses and Dissertations

Terrestrial organic matter (TOM) constitutes an important source of energy in many aquatic environments (streams, lakes, wetlands). This is the first study to examine the role of TOM in food webs of the rocky intertidal zone. We compared the consumption of red alder leaves (Alnus rubra) to common marine sources of drifting detritus along the southern Oregon coast (Nereocystis luetkeana, Phyllospadix spp., and Fucus gardneri). We used short term (hours to days) and long term (months) feeding experiments to compare the rate of consumption among each plant species during the Spring and Fall of 2014 …

Oxidative Insults Disrupt Mitochondrial Dynamics, Iraselia A. Garcia

Theses and Dissertations

Mitochondria form an organellar network to provide ATP to the cell. Mitochondrial DNA (mtDNA) combines with nuclear DNA to encode polypeptides critical to forming the complexes of oxidative phosphorylation in the mitochondrial inner membrane, which generate a transmembrane potential (ΔΨm) to synthesize ATP. This ΔΨm is required to maintain mitochondria fission/fusion dynamics: organellar fusion (mediated by OPA1) and fission events (mediated by DRP1) coordinately regulate mitochondrial dynamics. While oxidative stress correlates with mitochondrial dysfunction, it is unclear how oxidants affect mitochondrial structure/function homeostasis. This project seeks to establish and examine the impact of reactive oxygen species (ROS) on mitochondrial dynamics. …

Effectiveness Of The Flipped Classroom Model In Anatomy And Physiology Laboratory Courses At A Hispanic Serving Institution, Gerardo Sanchez

Theses and Dissertations

A flipped laboratory model involves significant preparation by the students on lab material prior to entry to the laboratory. This allows laboratory time to be focused on active learning through experiments. The aim of this study was to observe changes in student performance through the transition from a traditional laboratory format, to a flipped format. The data showed that for both Anatomy and Physiology (I and II) laboratories a more normal distribution of grades was observed once labs were flipped and lecture grade averages increased. Chi square and analysis of variance tests showed grade changes to a statistically significant degree, …

Bacterial Community Ecology Of The Colon In Mus Musculus, Rachel Marie Nettles

Theses and Dissertations

The gut microbiome is a community of closely interacting microbes living in the gastrointestinal tract. Its structure has direct relevance to health. Disturbances to the microbiome, such as due to antibiotic use, have been implicated in various diseases. The goal of this study was to determine how the gut microbiome reacts to and recovers from disturbance caused by antibiotics. Because diet also influences the microbiome, this study included the interaction between diet and antibiotics. Half of the mice in each diet treatment were given antibiotics to disturb their microbiomes. After cessation of antibiotics, mice were paired in combinations within diets …

Central Precocious Puberty Alters The Mammary Gland Epithelial Landscape In Female Rats, Alina M. Hamilton

Theses and Dissertations

Precocious puberty (PP) is a serious endocrine disorder associated with an increased risk for development of breast cancer (BC) later in life. However, the lack of a strong in vivo model has made it difficult to study this relationship. Our group has established manganese (Mn) as a non-toxic activator of the pubertal process. Recently we demonstrated that Mn-induced precocious puberty (MnPP) accelerates E2-regulated mammary gland (MG) development in prepubertal female rats, resulting in persistent proliferation and adult hyperplasia. Using this model, I demonstrate that precocious puberty alters steroidal regulation of proliferation in both the prepubertal and adult virgin MG, altering …

The Roles Of Diffusion And Bulk Flow In Neural Function And Alzheimer's Disease, Wade N. Dauberman

Theses and Dissertations

Alzheimer’s disease (AD) is a neurodegenerative disorder affecting close to 5.1 million Americans and its incidence is expected to rise with the higher number of people in the aging population. A hallmark of the disease is the production of the amyloid-beta (Aß) peptides and eventual self-assembly of these peptides into fibrils and extracellular Aß plaques. Both plaques and oligomers are proposed to be the direct cause of AD, but it remains unclear how these structures affect neuronal function and pathogenesis. While a direct toxic effect is currently the favored hypothesis, biomolecule aggregation is also known to play a role in …

Exploring The Biogeography Of South American Rainforest Understory Birds Using Morphological Variation In The Wedge-Billed Woodcreeper ( Glyphorynchus Spirurus ), Gregory Tito

Theses and Dissertations

Tropical rainforests in the Amazon Basin show an extraordinarily high degree of biodiversity, the reasons for which are poorly understood. A number of biogeographical models have been proposed to account for the variation present within and among species, including birds. This study tests the predictive ability of six major historical vicariant biogeographical models (Andean uplift, marine incursion, Amazonian lake, river barrier, refuge, and river refuge) using a large data set of morphological characters in the Wedge-billed Woodcreeper (Glyphorynchus spirurus), a small understory songbird found mostly in terra firme tropical rain forest. It also characterizes variation in key morphological characters and …

Integrative Analysis To Evaluate Similarity Between Brcaness Tumors And Brca Tumors, Weston Reed Bodily

Theses and Dissertations

The term "BRCAness" is used to describe breast-cancer patients who lack a germline mutation in BRCA1 or BRCA2, yet who are believed to express characteristics similar to patients who do have a germline mutation in BRCA1 or BRCA2. Although it is hypothesized that BRCAness is related to deficiency in the homologous recombination repair (HRR) pathways, relatively little is understood about what drives BRCAness or what criteria should be used to assign patients to this category. We hypothesized that patients whose tumor carries a genomic or epigenomic aberration in BRCA1 or BRCA2 should be classified under the BRCAness category and that …