Life Sciences Commons^™

Roles Of Siphon Flows In Suspension Feeding, Kevin Du Clos

Electronic Theses and Dissertations

Benthic marine suspension feeders provide an important link between benthic and pelagic ecosystems. The strength of this link is determined by suspension-feeding rates. Many studies have measured suspension-feeding rates using indirect clearance-rate methods, which are based on the depletion of suspended particles. Direct methods that measure the flow of water itself are less common, but they can be more broadly applied because clearance-rate measurements are affected by properties of the cleared particles. We present pumping rates for three species of suspension feeders, the clams Mya arenaria and Mercenaria mercenaria and the tunicate Ciona intestinalis, calculated using a direct method …

Structural And Functional Analysis Of Grapefruit Flavonol-Specific-3-O-Gt Mutant P145t, Sangam Kandel Mr

Electronic Theses and Dissertations

This research is focused on the study of the effect of mutating proline 145 to threonine on the substrate and regiospecificity of flavonol specific 3-O-glucosyltransferase (Cp3GT). While the mutant P145T enzyme did not glucosylate anthocyanidins, it did glucosylate flavanones and flavones in addition to retaining activity with flavonols. HPLC was used for product identification and showed mutant P145T glucosylated naringenin at the 7-OH position forming naringenin-7-O-glucoside and flavonols at the 3-OH position. Homology modeling and docking was done to predict the acceptor substrate recognition pattern and models were validated by experimental results. In other related work, …

Pharmacokinetics, Tissue Distribution, Synergistic Activity, And Antitumor Activity Of Two Isomeric Flavones, Crystal L. Whitted

Electronic Theses and Dissertations

Flavonoids are polyphenolic secondary metabolites found in plants that have bioactive properties including antiviral, antioxidant, and anticancer. Two isomeric flavone were extracted from Gnaphalium elegans and Achyrocline bogotensis, plants used by the people from the Andean region of South America as remedies for cancer. 5,7-dihydroxy-3,6,8-trimethoxy-2-phenyl-4H-chromen-4-one (5, 7–dihydroxy- 3, 6, 8 trimethoxy flavone/ flavone A) and 3,5-dihydroxy-6,7,8-trimethoxy-2-phenyl-4H-chromen-4-one (3, 5–dihydroxy-6, 7, 8–trimethoxy flavone/ flavone B) have shown antineoplastic activity against colon cancer cell lines dependent upon their differentiation status. Pharmacokinetic studies reported herein were used to determine dosing for antitumor assays, as well as determine target tissue concentration. These included the …

Transient Receptor Potential Cation Channel, Subfamilies V, Member 1 (Trpv1) And M, Member 1 (Trpm1) Contribute To Neural Signaling In Mouse Retina., Jennifer Noel

Electronic Theses and Dissertations

The retina processes light information through parallel pathways in order to extract and encode the visual scene. Light information is transmitted to the brain through approximately 30 ganglion cells (GCs), the retinal output neurons. Trp channels modulate the responses of retinal neurons within specific pathways. The study of the expression and function of the majority of Trp channels in the retina is largely in its infancy. My dissertation first investigated the expression and function of the transient receptor potential vanilloid-1 (TRPV1) receptor/channel in the retina. TRPV1, the first cloned and most highly studied Trp channel in the peripheral nervous system, …

Examination Of The Relevance Of Pi3k And Pten Pathway In Ustilago Maydis., Nathaniel Edward Dalton

Electronic Theses and Dissertations

Ustilago maydis is a fungal pathogen that is an obligate parasite on Zea mays (Corn) in order to undergo and complete its sexual life cycle. The cells grow as a haploid form until they meet a compatible partner and undergo a dimorphic switch from a budding yeast-like cell type to a filamentous dikaryon. Infection of the host plant is characterized by leaf chlorosis, anthocyanin content, and formation of large galls that develop on the stem, leaves, cobs, and flowers. Many signaling cascades such as MAPK and PKA are involved in the regulation of the infection lifecycle. The Phosphatidylinosotiol 3 Kinase/ …

Identification And Characterization Of Genes Involved In Metabolism Of N5 Monoene Precursors To N5 Anacardic Acids In The Trichomes Of Pelargonium X Hortorum., Richa A. Singhal

Electronic Theses and Dissertations

Unusual monoenoic fatty acids (UMFA’s) and specialized metabolites called anacardic acids (AnAc) are produced in glandular trichomes of Pelargonium ´ hortorum (geranium). The UMFA’s, 16:1^∆11 and 18:1^∆13 are precursors for the synthesis of unsaturated AnAc 22:1n5and 24:1n5 that contribute to pest resistance in geraniums. UMFAs and their derived AnAc metabolites not only provide a useful biological marker that differentiates the biosynthetic pathway for unusual mononenes from the common fatty acids (i.e. stearic, palmitic, oleic, linoleic and linolenic) but also have industrial, medical and agricultural applications. Fatty acid biosynthesis enzymes like acyl carrier proteins (ACPs); thioesterases (TEs) and β-ketoacyl-ACP …

Spreading Speeds Along Shifting Resource Gradients In Reaction-Diffusion Models And Lattice Differential Equations., Jin Shang

Electronic Theses and Dissertations

A reaction-diffusion model and a lattice differential equation are introduced to describe the persistence and spread of a species along a shifting habitat gradient. The species is assumed to grow everywhere in space and its growth rate is assumed to be monotone and positive along the habitat region. We show that the persistence and spreading dynamics of a species are dependent on the speed of the shifting edge of the favorable habitat, c, as well as c^*(∞) and c^*(−∞), which are formulated in terms of the dispersal kernel and species growth rates in both directions. When …

Dietary Resource Utilization Patterns And Head Morphology Among Three Sympatric Watersnake Species., Micah Warren Perkins

Electronic Theses and Dissertations

The coexistence of similar species may be related to a variety of resource utilization differences. Dietary resource utilization variation may be the most important difference allowing for the coexistence of sympatric snake species. Many watersnakes (Nerodia spp.) live in sympatry and use similar aquatic habitats feeding on similar prey. While these sympatric watersnakes may have different general foraging patterns, snake diet may be affected by a variety of factors. Therefore, I initiated an investigation to understand the coexistence of sympatric plain-bellied (N. erythrogaster), diamondback (N. rhombifer) and northern (N. sipedon) watersnakes by addressing …

Shortnose Sturgeon (Acipenser Brevirostrum) Spawning Potential In The Penobscot River, Maine: Considering Dam Removals And Emerging Threats, Catherine Johnston

Electronic Theses and Dissertations

Dam removals from the Penobscot River in Maine restored access to freshwater habitat critical for the life cycle of endangered shortnose sturgeon. Prior to the dam removals, shortnose sturgeon spawning activity had not been documented. Instead, evidence suggested that individuals emigrated from the Penobscot River to spawn in the Kennebec complex, 140 km away. A central question of this thesis was whether spawning activity would commence in the first two years following dam removal. Consistent with pre-dam removal movement patterns determined using acoustic telemetry, the majority (78%) of tagged individuals emigrated from the Penobscot River at some point over the …

Characterization Of Sip470, A Family 1 Lipid Transfer Protein And Its Role In Plant Stress Signaling, Timothy Ndagi Audam

Electronic Theses and Dissertations

SIP470, a putative tobacco lipid transfer protein, was identified in a yeast two-hybrid screen to interact with SABP2. SABP2 is a critical role in SA-mediated signaling in tobacco and other plants. In vitro studies using purified recombinant SIP470 confirmed that it is a lipid binding protein. In an attempt to determine its role in mediating stress responses, Arabidopsis T-DNA insertion knockout lines lacking SIP470 homolog were used for the analysis. These mutant plants were defective in basal resistance against microbial pathogens. Expression of defense gene PR-1 was also delayed in these mutant plants. Interestingly, these mutant plants were not defective …

Venom Peptides Lasioglossin Ii And Mastoparan B As Escherichia Coli Atp Synthase Inhibitors, Rafiat Ajoke Bello

Electronic Theses and Dissertations

The inhibitory effects on Escherichia coli ATPase activity by two venom peptides, lasioglossin II and mastoparan B. Membrane bound F₁F_O ATP synthase was isolated from E. coli strain pBWU13.4/DK8 and treated with varied concentrations of lasioglossin II and mastoparan B. Lasioglossin II caused very low inhibition of ATPase activity, but the inhibition profile of mastoparan B was suggestive of an interesting biological effect. A relatively shorter total length, a smaller net positive charge, and a reduced amphipathic character of both peptides, as compared to previously tested antimicrobial peptides, may account for the limited degree of inhibition observed …

Effects Of Acclimation On Temperature Tolerance And Oxidative Damage In Daphnia Magna, Kailea J. Holbrook Ms.

Electronic Theses and Dissertations

Freshwater zooplankton crustacean Daphnia frequently face strong temperature fluctuations in its natural environment, which necessitates adaptive plastic responses. This study focuses on changes in lipid peroxidation and total oxidative capacity in Daphnia tissues in response to long-term and short-term temperature changes.

Long-term acclimation to 28ºC helped Daphnia survive longer at lethally high temperatures. This difference, however, was not accompanied by changes in lipid peroxidation, indicating that it isn’t a good measure of damage or predictor of temperature tolerance.

On the other hand, total oxidation capacity was lower 28ºC- than in 18ºC-acclimated Daphnia, suggesting that acclimation resulted in higher amounts …

Insights Into The Introduction Histories And Population Genetic Dynamics Of The Nile Monitor (Varanus Niloticus) And Argentine Black And White Tegu (Salvator Merianae) In Florida., Jared Price Wood

Electronic Theses and Dissertations

This dissertation examines the population genetic dynamics of two Florida invasives: the Nile monitor (Varanus niloticus) and Argentine black and white tegu (Salvator merianae). I also provide insights into the introduction histories of both species. This study was developed as part of a collaborative effort with the Florida Wildlife Commission to expand our knowledge of these highly detrimental, invasive lizards. All research activities involving animals and animal tissues were approved by the University of Louisville’s Institutional Animal Care and Use Committee (IACUC Proposal #: 12024). I start with a brief introduction into what makes invasive species …

Sources Of Ecologically Important Trait Variation In Mosquitofish (Gambusia Affinis And Gambusia Holbrooki), Heather Ann Arnett

Electronic Theses and Dissertations

The study of contemporary evolution and eco-evolutionary dynamics is classically defined in terms of genetic evolution, but the actual suite of processes driving contemporary trait change is likely much more complex than often credited. This dissertation considers additional mechanisms of trait change that might be important to an emerging model system for study of contemporary evolution and eco-evolutionary dynamics. Specifically, the research focuses on phenotypically plastic and demographic trait variation in Eastern and Western Mosquitofish (Gambusia affinis and G. holbrooki) facing the major ecological gradient of predation risk. Plasticity experiments employed a common-garden rearing design to manipulate fish …

Habitat Distribution And Abundance Of Crayfishes In Two Florida Spring-Fed Rivers, Tiffani Manteuffel

Electronic Theses and Dissertations

Crayfish are an economically and ecologically important invertebrate, however, research on crayfish in native habitats is patchy at best, including in Florida, even though the Southeastern U.S. is one of the most speciose areas globally. This study investigated patterns of abundance and habitat distribution of two crayfishes (Procambarus paeninsulanus and P. fallax) in two Florida spring-fed rivers (Wakulla River and Silver River, respectively). Study sites were surveyed once each season from April 2015 to March 2016 with baited minnow traps checked every other day, four times each survey. Habitat and environmental parameters evaluated included dominant vegetation or bottom type, percent …

Pyroglutamylated Amyloid Beta Peptides Enhance Non-Fibrillogenic Aggregation Of The Unmodified Peptide, Gregory Goldblatt

Electronic Theses and Dissertations

Alzheimer's disease (AD) is accompanied by abnormal extracellular deposition of amyloid b (Ab) peptide. This has led to the amyloid cascade hypothesis, causatively relating Ab with AD. While Ab deposits assume a fibrillar cross-b structure, prefibrillar oligomers of Ab have been identified as the main cytotoxic agents in AD. Pyroglutamylated amyloid beta (AbpE) peptides are N-terminally truncated and pyroglutamylated (at Glu3 or Glu11) Ab molecules that display enhanced cytotoxicity and represent up to 50% of total Ab in AD brains. AbpE significantly enhances the toxicity of unmodified Ab by an unknown mechanism. Although in situ Ab populations are heterogeneous, the …

Assessment Of Staphylococcus Aureus Genetics: Clinical Versus Community Epidemiology, Matthew Lawrance

Electronic Theses and Dissertations

Staphylococcus aureus has an historical relationship with anthropogenic environments, particularly hospitals, where infection characteristics differ from community-acquired disease. This has promoted a designation of strains as healthcare or community associated. Despite this affiliation, genetic approaches have failed to support these groupings. In order to establish the genetic relationship between S. aureus from differing anthropogenic environments, I have analyzed the relatedness between three cohorts of S. aureus: nasal carriage isolates from community participants, infectious isolates from hospitals, and a cohort from an uninvestigated environment, an ambulatory clinic. Multilocus Sequence Typing (MLST) and Staphylococcus aureus protein a (spa) repeat regions were analyzed …

Transforming The Aquatic Urban Landscape: Nutrient Status And Management Of Stormwater Basins, Lindsay Skovira

Electronic Theses and Dissertations

Urbanization is a largely irreversible anthropogenic change that degrades environmental quality, including aquatic ecosystems. Stormwater ponds are a popular best management practice (BMP) to mitigate the effects of urban land use on downstream water bodies and contribute significantly to the total area of aquatic ecosystems in some urban watersheds. My research investigated the distribution of stormwater ponds and examined how different urban land uses influenced biophysicochemical conditions and management of those ponds in a rapidly developing suburban watershed in the Econlockhatchee River basin in Florida, USA. I evaluated limnological and ecological parameters in randomly-selected ponds distributed among three urban land-use …

Role Of Kruppel-Like Factor 8 (Klf8) In Cancer And Cardiomyopathy, Satadru Lahiri

Electronic Theses and Dissertations

Cancer and cardiovascular diseases are two most fatal diseases causing innumerable death each year. Understanding the mechanisms underlying these diseases is critical for developing proper therapeutic approach. Kruppel-like factor 8 (KLF8) is a member of Kruppel-like family transcription factors that is overexpressed in many types of cancers. There is no report on role of KLF8 in cardiovascular diseases to date. KLF8 transcriptionally activates or represses a host of target genes to promote cancer cell proliferation, migration, invasion and epithelial to mesenchymal transition during tumor progression. Studies proposed in this thesis identified a novel posttranslational modification of KLF8 essential for its …

Involvement Of Mirnas In The Development Of Androgen Independent Prostate Cancer, Richard Ottman

Electronic Theses and Dissertations

Development of resistance to androgen deprivation therapy (ADT) is a major obstacle for the management of advanced prostate cancer. Therapies with androgen receptor (AR) antagonists and androgen withdrawal initially result in tumor regression but development of compensatory mechanisms including AR bypass signaling leads to tumor re-growth, independent of circulating androgens. The result is the emergence of castration resistant prostate cancer (CRPC), a highly morbid disease exhibiting aberrant expression of many protein-coding and non-coding genes. Under the umbrella of non-coding RNAs is a class of small regulatory RNAs referred to as microRNAs (miRNAs). MicroRNAs are believed to function in the maintenance …

Macgillivray's Seaside Sparrow (Ammodramus Maritimus Macgillivraii) Breeding Biology & Population Density At Tom Yawkey Wildlife Center, Yianni P. Laskaris

Electronic Theses and Dissertations

MacGillivray's Seaside Sparrow (Ammodramus maritimus macgillivraii) is a coastal marsh species sensitive to habitat alteration and threatened by coastal wetland loss. Data on seaside sparrow distribution, breeding success, and critical habitats are lacking in South Carolina. To better understand the demographics and incubation behavior of the species, I monitored breeding success, densities, song output, and presence of predators at three 7-hectare plots at the densest known population in the state. I also placed temperature data-loggers in a subset of nests to discern any links between incubation behavior and nest fate. Densities varied from a low of 5 birds/ha in a …

Analysis Of Starch Branching Enzyme 1 (Sbe1) Gene In Maize, Abiskar Gyawali

Electronic Theses and Dissertations

A previous study revealed a quantitative trait locus (QTL) in maize on the short arm of chromosome 5 (5S) for endosperm amylose content. In that original study, both low and high amylose parental lines, H99ae and GEMS-0067 respectively, were homozygous recessive for amylose extender 1 (ae1) and the polymorphism responsible for this QTL was additive (semi-dominant). Located within the QTL interval is starch branching enzyme 1 (sbe1), which makes it a candidate gene. In order to test whether a polymorphism in sbe1 is the source of this QTL, we crossed a plant homozygous for ae1 and sbe1-Mu onto a …

Flying Under The Lidar: Relating Forest Structure To Bat Community Diversity, Anna Schneider Swanson

Electronic Theses and Dissertations

Bats are important to many ecological processes such as pollination, insect (and by proxy, disease) control, and seed dispersal and can be used to monitor ecosystem health. However, they are facing unprecedented extinction risks from habitat degradation as well as pressures from pathogens (e.g., white-nose syndrome) and wind turbines. LiDAR allows ecologists to measure structural variables of forested landscapes with increased precision and accuracy at broader spatial scales than previously possible. This study used airborne LiDAR to classify forest habitat/canopy structure at the Ordway-Swisher Biological Station (OSBS) in north central Florida. LiDAR data were acquired by the National Ecological Observatory …

Pasture Management, The Red Imported Fire Ant (Solenopsis Invicta) And Dung Beetle Mediated Ecosystem Services, Christen Steele

Electronic Theses and Dissertations

Grazing animals in Florida deposit over 20 million metric tons of dung per year, making dung a significant non-point source of pollution (extrapolated from Fincher, 1981). Degradation of this dung occurs naturally, primarily due to a diverse group of beetles (Order Coleoptera) primarily in the families Scarabaeidae and Geotrupidae(hereafter dung beetles). Dung that is not degraded becomes a non-point source of pollutants and may be leached into water bodies. Additionally, dung provides an incubation site for the pests and parasites of both humans and livestock. Thus, as dung beetles consume and degrade dung, they provide a multitude of ecosystem services …

From Pet To Pest? The Potential Global Range And Food Web Effects Of A Generalist Carnivore, Hannah Bevan

Electronic Theses and Dissertations

The Nile monitor lizard [Varanus niloticus (Linnaeus, 1766)] is a generalist carnivore, native to Sub-Saharan Africa and the Nile River but now established in North America as a result of the pet trade. Once introduced, they are a potential invasive threat to native wildlife. Here, I create ensemble species distribution models (SDMs) to predict the global distribution of this generalist carnivore given current and future climate conditions. I then quantify the monitor's potential effects on 85 food webs representing >900 different species within the projected regions based on stomach content data. Climate, vegetation, and elevation data are used for 507 …

Ex-Vivo Slaughterhouse Porcine Crystalloid-Perfused Beating Heart Via Langendorff Method, Rahiemin Talukder

Electronic Theses and Dissertations

The objective of this study was to resuscitate isolated beating porcine hearts obtained from slaughterhouse swine for a minimum of 1 hour with a crystalloid buffer reperfusion instead of blood via an extracorporeal Langendorff apparatus. The isolated beating heart functions outside of the body under simulated physiologic conditions. Live functional anatomy was controlled under benchtop experimental settings. Porcine hearts (26 total) were topically cooled with saline. 300mL of 25°C cardioplegia with 20KU Streptokinase was preflushed via aortic root. WIT was less than 5 minutes. 1L 4°C cardioplegia was flushed antegrade with aortic cannula (Group 1) or coronary catheterization (Group 2). …

Metabolomics Of Mammalian And Cellular Models Of Aging, Nathan Gonzales Duval

Electronic Theses and Dissertations

Aging is often associated with impaired cognition and a progressive loss of organ function over time accompanied by an increased susceptibility for many disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), heart disease, osteoporosis, type II diabetes, and many forms of cancer. With a rapidly aging population, the negative impacts of aging and age-related disorders is a major cause of increased human suffering both for affected individuals and for families and caregivers. Metabolic changes are also apparent in normal aging, but may increase in magnitude or nature with accompanying disease states or with accelerated aging. Thus, studying aging in a …

The Role Of P38 Mapk In Protein Homeostasis And Aging, Sarah Mae Ryan

Electronic Theses and Dissertations

Aging is characterized by a failure to maintain proper protein homeostasis, potentially leading to tissue dysfunction. Though a variety of genes have been found to regulate lifespan and age-related behaviors how these genetic factors contribute to protein homeostasis has not been fully explored. Here, we report that the evolutionarily conserved aging gene p38 MAPK (p38Kb) regulates age-dependent protein homeostasis. Over-expression of p38Kb results in reduced protein aggregation, while knockout of p38Kb leads to increased protein aggregation. Furthermore, we find that p38Kb regulates protein homeostasis, lifespan, and age-dependent locomotor functions through an interaction with the Chaperone Assisted Selective Autophagy complex; a …

Neuroprotection Comparison Of Different Nutraceutical Compounds Against Mechanistically Distinct Cell Death Inducing Agents, Faten I. Taram

Electronic Theses and Dissertations

Neurodegenerative diseases like Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), include the progressive loss of structure and function of neurons leading to neuronal death. All of these diseases are fatal, as there is no cure for them. The causes of these diseases are unknown; however, there are many proposed mechanisms that lead to neurodegenerative diseases. Oxidative stress is the leading cause of cell death in neurodegenerative diseases, in addition to other mechanisms including endoplasmic reticulum stress, proteasome inhibition, nitrosative stress, inflammation and excitotoxicity. More understanding of the death mechanisms at work in neurodegeneration is necessary to …

Akap150 Dynamics In Anterior Pituitary Cells, Kristen E. Dew

Electronic Theses and Dissertations

Cellular communication occurs as a result of changes in signaling pathways. A well-studied signaling pathway is through G protein coupled receptors (GPCRs). In gonadotropes, GPCR stimulation by GnRH leads to the activation of protein kinase A (PKA). Activated PKA can phosphorylate ion channels, potentially causing an influx of calcium, depolarization and secretion of hormones. A scaffolding protein known as AKAP150 anchors PKA near L-type calcium channels. In addition, AKAP150 anchors phosphatases, which provides temporal control during signaling events. It was recently shown that AKAP150 is mobile in neuronal dendrites, providing regulation to where the signaling cascade occurs in the cell. …