Life Sciences Commons^™

Synthesis And Characterization Of Targeted Bar Encapsulated Polylactic-Co-Glycolic Acid Nanoparticles To Inhibit Porphyromonas Gingivalis Biofilm Formation., Ranjith Radha Krishnan

Electronic Theses and Dissertations

Periodontal disease is one of the most prevalent infectious diseases worldwide. Between 30-50% of the global adult population suffers from periodontal disease. Some form of periodontitis is present in 46% of American adults, corresponding to annual expenditures in excess of 14 billion dollars for treatment and prevention. Current treatments for periodontal diseases involve mechanical removal of plaque, correction of risk factors, gingival surgery and/or antibiotic therapy. To our knowledge there is no effective therapeutic approach that aims to limit pathogen colonization of the oral biofilm or re-colonization after treatment. Interaction of the pathogen Porphyromonas gingivalis with oral streptococci is critical …

Particulate Hexavalent Chromium Does Not Induce Centrosome Amplification In Sperm Whale And Bowhead Whale Cells., Jennifer Haruka Toyoda

Electronic Theses and Dissertations

Hexavalent chromium [Cr(VI)] is a widespread environmental and occupational carcinogen. The mechanism of carcinogenesis remains poorly understood, but chromosome instability (CIN) is the dominant theory. How numerical CIN arises is unclear, but it correlates with centrosome amplification. Both phenotypes are hallmarks of cancers, early events in carcinogenesis, and have been shown to occur after Cr(VI) exposure to human skin and lung fibroblasts. In this study, we investigate numerical CIN and centrosome amplification in whale cells. Whales are our closest marine relatives, have long lifespans, and are exposed to environmental Cr(VI). Importantly, they have low cancer rates and cell culture studies …

Neural Correlates Relating To Executive Function, Intelligence, And Anxiety., Sarah K L'Heureux

College of Arts & Sciences Senior Honors Theses

The human brain is a complex organ responsible for not only perceiving and sensing information in one’s environment, but also integrating and analyzing these details in a way that will allow an individual to comprehend the material. Scientists for centuries have been curious as to why people process their emotions and thoughts differently, resulting in unique and varied behavior. The manner in which a person comprehends information and whether or not they feel anxious as a result, may be connected to their intellectual and functional capacity. Human intelligence and the ability to function at a high level may be related …

Cd11b Regulation Of B Cell Receptor Signaling In Health And Systemic Lupus Erythematosus., Paul Lorenzo Dascani

Electronic Theses and Dissertations

Loss of function mutation in CD11b has been associated with incidence of systemic lupus erythematosus (SLE), a disease driven by B cell production of pathogenic autoimmune antibody. Our previous work has revealed the ability of CD11b to regulate B cell receptor (BCR) signaling and control autoimmune disease in mice. However, how CD11b regulates the immune response under normal conditions remains unknown. Through the use of a CD11b knockout model, we demonstrated that CD11b-deficient mice have an elevated antigen-specific humoral response in a Th2 type immunization. Deletion of CD11b resulted in elevated serum IgM and IgG antibody, increases in antigen-specific germinal …

Identification And Functional Characterization Of Effectors From An Anther Smut Fungus, Microbotryum Lychnidis-Dioicae., Venkata Swathi Kuppireddy

Electronic Theses and Dissertations

Microbotryum lychnidis-dioicae causes anther smut fungus in its host plant, Silene latifolia. The goal of this work is to identify and characterize the virulence determinants of this pathogen to better understand the molecular basis behind this host-pathogen interaction. This work studied for the first time the key effectors in the mechanism of infection by this fungal species. Using, yeast two-hybrid screens, I have identified the host plant interaction partners for the effector, MVLG_01732. A second effector MVLG_05720, interacts with other fungal proteins that appear to facilitate the fungal establishment and colonization during the infection. Our findings indicate that a …

Impacts Of Ammonia And Temperature On Freshwater Snail Behavior And Physiology., Megan Christine Dewhatley

Electronic Theses and Dissertations

Gastropods are one of the most imperiled groups of animals in North America, yet there are major gaps in the literature pertaining to pollutants and climate change, and especially sublethal impacts. This dissertation assesses the effects of climate warming and unionized ammonia (NH₃), one of the most abundant water pollutants, on the behavior and physiology of two caenogastropod snails: fine-ridged elimia (Elimia semicarinata) and Shawnee rocksnails (Lithasia obovata) (Gastropoda: Neotaenioglossa: Pleuroceridae). Righting behavior, or the movement used by snails to turn themselves right-side-up, was used as the main endpoint; delays in this behavior compromise …

Coagulation Factor Xiiia: Biochemical Properties Underlying Physiological Function., Boris Anokhin

Electronic Theses and Dissertations

Factor XIIIA (FXIIIA) is a transglutaminase that crosslinks intra- and extracellular protein substrates. The oligomeric state of active FXIIIA remains controversial, and the present work commenced with addressing this issue. The results of size exclusion chromatography and analytical ultracentrifugation confirmed a dimeric state for zymogen and, for the first time, indicated a monomeric state for the active FXIIIA in solution. Comparing sedimentation properties of proteolytically and nonproteolytically activated FXIIIA suggested conformational and functional differences between the two forms. Those differences were further assessed in a series of catalytic activity studies. Kinetic analysis revealed affinity for the glutamine substrate was higher …

Functional Consequence Of Psat1 Association On Pkm2'S Inherent Enzymatic Activity., Alexis Avidan Vega

Electronic Theses and Dissertations

Pyruvate kinase M2 (PKM2) is predominantly found in tumors, where it allows the cancer cell to adapt to metabolic conditions through allosteric regulation of its activity. We recently discovered that phosphoserine aminotransferase 1 (PSAT1) associates with and activates PKM2. Here, I sought to affirm PSAT1's ability to increase PKM2 activity through kinetic and association studies of wild-type or mutant PKM2 enzymes. I demonstrate that His-tagged WT and mutant PKM2 enzymes are active, exhibit different kinetics, yet cannot be activated by PSAT1. Comparison studies using untagged WT PKM2 suggest that inclusion of the His-tag disrupts PSAT1 association. In support, pull-down strategies …

Epidermal Growth Factor-Like Ligands Regulate Dimer Selection., Jamie S. Rush

Electronic Theses and Dissertations

There are thirteen known endogenous EGF-like ligands. We previously reported that Betacellulin (BTC) increases ligand-mediated corneal wound healing more than Epidermal Growth Factor (EGF) [Peterson et al. (2014) IOVS 55(5):2870-80], although the molecular reason for this is unknown. Despite being better at promoting wound healing via enhanced cell migration, BTC has reduced receptor affinity and weaker induction of EGFR phosphorylation. These data indicate that BTC’s response is not due to enhanced affinity or EGFR-kinase activity. Receptor phosphorylation and proximity ligation assays indicate that BTC treatment significantly increases ErbB3 phosphorylation and EGFR:ErbB3 heterodimers. BTC traffics EGFR at a faster rate than …

Role Of Trkb-Signaling In Taste Development And Function., Jennifer Rios-Pilier

Electronic Theses and Dissertations

In the geniculate ganglion, taste neurons likely differentiate into subtypes during development, but very little is known about how these neurons are defined molecularly or how they differentiate. Embryonically, geniculate neuron development is regulated by the growth factor, brain ­derived neurotrophic factor (BDNF). Postnatally, BDNF becomes restricted to subpopulations of taste receptor cells with specific functions, primarily sour responding. I hypothesized that during development, the receptor for BDNF, tropomyosin kinase B receptor (TrkB), also becomes restricted to a neuronal subset. I used transgenic mouse models to label and quantify both geniculate sensory neurons (Phox2b+), and those expressing TrkB (GFP) across …

Egfr Signaling From The Early Endosome., Julie A. Gosney

Electronic Theses and Dissertations

The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that is an integral component of proliferative signaling. When activated by a ligand at the plasma membrane, EGFR dimerizes with another ErbB family receptor, leading to kinase domain activation and transphosphorylation of C-terminus tyrosine residues. These phosphotyrosines act as crucial regulators of EGFR signaling as effector proteins dock to the receptor at these sites. The receptor undergoes clathrin-mediated endocytosis into early endosomes, where it can then be trafficked to a lysosome for degradation. However, the kinase domain of EGFR retains its activity during trafficking, suggesting that EGFR can continue …

The N-Terminal Methyltransferase Homologs Nrmt1 And Nrmt2 Exhibit Novel Regulation Of Activity Through Heterotrimer Formation., Jon David Faughn

Electronic Theses and Dissertations

Protein, DNA, and RNA methyltransferases have an ever-expanding list of novel substrates and catalytic activities. Even within families and between homologs, it is becoming clear the intricacies of methyltransferase specificity and regulation are far more diverse than originally thought. In addition to specific substrates and distinct methylation levels, methyltransferase activity can be altered through formation of complexes with close homologs. This work involves the N-terminal methyltransferase homologs NRMT1 and NRMT2. NRMT1 is a ubiquitously expressed distributive trimethylase. NRMT2 is a monomethylase expressed at low levels and in a tissue-specific manner. They are both nuclear methyltransferases with overlapping target consensus sequences …

Unfolded Protein Response Pathways In Skeletal Muscle Homeostasis., Kyle R. Bohnert

Electronic Theses and Dissertations

Skeletal muscle mass, contractile properties, and metabolic function are regulated through the coordinated activation of multiple intracellular signaling pathways and genetic reprogramming. The endoplasmic reticulum (ER) plays a pivotal role in protein folding and calcium homeostasis in many cell types, including skeletal muscle. Disruption of calcium levels or accumulation of misfolded proteins in the ER lumen leads to stress, which results in the activation of a signaling network called the unfolded protein response (UPR). Further, recent studies have suggested that in certain conditions, UPR pathways can be activated independent of ER stress. However, the role of ER stress and the …

The Population Ecology And Behavior Of The Cave Salamander, Eurycea Lucifuga (Rafinesque, 1822)., Joseph Gavin Bradley

Electronic Theses and Dissertations

The Cave Salamander, Eurycea lucifuga (Rafinesque, 1822), is a little-known species, yet a common inhabitant of caves in the eastern United States. Salamanders are often important components of ecological communities and ecosystems, influencing critical processes such as nutrient cycling and community composition through their predation on invertebrates. Cave-dwelling salamanders such as E. lucifuga may thus appreciably influence the relatively simple ecosystems and communities of caves. Any such influence may be particularly important because these habitats and the organisms that reside in them are often of conservation concern. I used non-invasive methods to study the demographics, movements, and habitat selection of …

Evaluation Of Drug-Loaded Gold Nanoparticle Cytotoxicity As A Function Of Tumor Tissue Heterogeneity., Hunter Allan Miller

Electronic Theses and Dissertations

The inherent heterogeneity of tumor tissue presents a major challenge to nanoparticle-medicated drug delivery. This heterogeneity spans from the molecular to the cellular (cell types) and to the tissue (vasculature, extra-cellular matrix) scales. Here we employ computational modeling to evaluate therapeutic response as a function of vascular-induced tumor tissue heterogeneity. Using data with three-layered gold nanoparticles loaded with cisplatin, nanotherapy is simulated with different levels of tissue heterogeneity, and the treatment response is measured in terms of tumor regression. The results show that tumor vascular density non-trivially influences the nanoparticle uptake and washout, and the associated tissue response. The drug …

Dead Wood And Decomposition In A Tropical Forest : Vertical Patterns, Long-Term Processes, And The Role Of Lightning., Evan Matthew Gora

Electronic Theses and Dissertations

This dissertation investigates the distribution, production, and decomposition of dead wood (or woody debris) in a lowland tropical forest within the Barro Colorado Nature Monument in Panama. Although the importance of woody debris is widely accepted, information describing components of WD pools and fluxes is generally separated in both time and space, particularly in understudied tropical forests. Here I provide a comprehensive inventory of woody debris in a lowland tropical forest (Chapter 1). Woody debris is highly aggregated and difficult to quantify, and this study demonstrates that historic estimates of woody debris pools and fluxes underestimate their uncertainty. In a …

Wnt/Β-Catenin Mediated Cancer Stem Cell Activation In Hepatocellular Carcinoma., Harshulkumar M. Pandit

Electronic Theses and Dissertations

Hepatocellular carcinoma (HCC) is one of the deadliest cancers, with variable presentation, high chemotherapy resistance and early tumor recurrence. In this dissertation, we have systematically enriched, identified and characterized HCC cancer stem cells (CSCs) from 3 different HCC cell lines (Hepa1-6, HepG2, and Hep3B) using in vitro serum-free culture method. Enriched spheroids acquired CSC properties, primarily self-renewal capability, spheroid formation ability, and drug resistance. Heterogeneous CSCs enriched from Hepa1-6 cells demonstrated higher tumor initiation and proliferation capability in vivo, compared to control HCC cells in orthotopic immunocompetent mouse model. EpCAM+ CSCs were significantly enriched within heterogeneous Hepa1-6 CSC spheroids. Consequently, …

A Novel Fibroblast Growth Factor 1 Variant Reverses Nonalcoholic Fatty Liver Disease In Type 2 Diabetes., Qian Lin

Electronic Theses and Dissertations

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder and is strongly associated with type 2 diabetes (T2D). Our recently engineered FGF1 partial agonist, carrying triple mutations (FGF1^△HBS) exhibits greatly reduced proliferative potential, while preserving the full metabolic activity of wild-type FGF1. This study tests the preventive and therapeutic effects of FGF1^△HBS on NAFLD in db/db T2D and explores potential mechanisms. The results showed that administration of FGF1^△HBS to 2-month-old db/db mice for 2 months constantly lowered blood glucose levels, improved insulin sensitivity, and lowered liver weight, lipid deposition, and …

Bayesian Analytical Approaches For Metabolomics : A Novel Method For Molecular Structure-Informed Metabolite Interaction Modeling, A Novel Diagnostic Model For Differentiating Myocardial Infarction Type, And Approaches For Compound Identification Given Mass Spectrometry Data., Patrick J. Trainor

Electronic Theses and Dissertations

Metabolomics, the study of small molecules in biological systems, has enjoyed great success in enabling researchers to examine disease-associated metabolic dysregulation and has been utilized for the discovery biomarkers of disease and phenotypic states. In spite of recent technological advances in the analytical platforms utilized in metabolomics and the proliferation of tools for the analysis of metabolomics data, significant challenges in metabolomics data analyses remain. In this dissertation, we present three of these challenges and Bayesian methodological solutions for each. In the first part we develop a new methodology to serve a basis for making higher order inferences in metabolomics, …

Deciphering The Role Of Human Arylamine N-Acetyltransferase 1 (Nat1) In Breast Cancer Cell Metabolism Using A Systems Biology Approach., Samantha Marie Carlisle

Electronic Theses and Dissertations

Background: Human arylamine N-acetyltransferase 1 (NAT1) is a phase II xenobiotic metabolizing enzyme found in almost all tissues. NAT1 can additionally hydrolyze acetyl-coenzyme A (acetyl-CoA) in the absence of an arylamine substrate. NAT1 expression varies inter-individually and is elevated in several cancers including estrogen receptor positive (ER+) breast cancers. Additionally, multiple studies have shown the knockdown of NAT1, by both small molecule inhibition and siRNA methods, in breast cancer cells leads to decreased invasive ability and proliferation and decreased anchorage-independent colony formation. However, the exact mechanism by which NAT1 expression affects cancer risk and progression remains unclear. Additionally, consequences …

Organization And Development Of Cholinergic Input To The Mouse Visual Thalamus., Guela Sokhadze

Electronic Theses and Dissertations

Cholinergic signaling plays a vital role in modulating the flow of sensory information through thalamic circuits in a state-dependent manner. In the dorsal lateral geniculate nucleus (dLGN), the thalamic visual relay, release of acetylcholine (ACh) contributes to enhanced thalamocortical transfer of retinal signal during behavioral states of arousal, wakefulness, and sleep/wake transitions. Moreover, ACh modulates activity of the thalamic reticular nucleus (TRN), a structure which provides inhibitory input to dLGN. While several cholinergic nuclei have been shown to innervate dLGN and TRN, it is unclear how projections from each area are organized. Furthermore, little is known of how or when …

Canonical Nuclear Factor-Κb Signaling In Satellite Stem Cell Homeostasis And Function., Alex R. Straughn

Electronic Theses and Dissertations

Satellite cells are adult stem cells that are required for the regeneration of skeletal muscle following injury. However, the signaling mechanisms that regulate satellite stem cell homeostasis and function in adult animals remain less understood. Nuclear factor-kappa B (NF-kB) is a major nuclear transcription factor that regulates the gene expression of a plethora of molecules involved in cellular proliferation, differentiation, survival, and the inflammatory immune response. NF-kB can be activated through a canonical or non-canonical pathway. However, the role of canonical NF-kB signaling in the regulation of satellite stem cell function during skeletal muscle regeneration has not been yet investigated …

Enhancement Of Nafld Risk By Vinyl Chloride : Role Of Adipose Tissue In A Mouse Model., Brenna R. Kaelin

College of Arts & Sciences Senior Honors Theses

Background: Vinyl chloride (VC), an environmental contaminant, is directly hepatotoxic at high concentrations. However, our group has recently demonstrated that VC and the VC metabolite chloroethanol (CE), at concentrations that are not considered hepatotoxic, enhanced liver injury caused by high-fat diet (HFD). These data therefore suggest that the impact of VC exposure on hepatic tissue may be enhanced with underlying metabolic syndrome and/or liver injury. It is known that there is an axis between adipose and hepatic tissue in non-alcoholic fatty liver disease (NAFLD), with the former impacting pathology in the hepatic tissue via release of pro-inflammatory cytokines and/or lipolysis. …

Dsba-L Protein Levels In White Adipose Tissue In An Obesity Model., Madison E. Kerley

College of Arts & Sciences Senior Honors Theses

Adiponectin is an adipose tissue-secreted protein found in three isoforms. Disulfide bond A oxidoreductase-like protein (DsbA-L) is thought to assist with protomeric disulfide bonding to generate the HMW (high molecular weight) isoform, which regulates insulin sensitivity. Both adiponectin and DsbA-L were previously found to negatively correlate with obesity.

Immunoblots were conducted on adipose tissue samples from male mice fed a high or low-fat diet for 6, 10, or 16 weeks. Immunoblots from high-fat diet-fed mice revealed double bands for DsbA-L. High and low molecular weight bands were analyzed together, revealing significantly higher relative band densities with 10 and 16-week high-fat …

The Role Of Ferric Reduction Oxidases In Plant Anti-Herbivore Defense., Virginia C. Nunamaker

College of Arts & Sciences Senior Honors Theses

Iron is an essential element required for plants to carry out metabolic functions such as photosynthesis, heme biosynthesis, and chlorophyll biosynthesis. Within Arabidopsis thaliana, eight ferric reduction oxidase (FRO) genes function in iron uptake and homeostasis with tissue specific expression. However, little else is known regarding the biological role of FROs. Recent studies identify the FRO gene family as particularly responsive to the green leaf plant derived volatile (GLV) cis-3-hexenyl acetate (z3HAC). Since z3HAC acts as a wound signal and cues unaffected parts of the plant to prime defenses prior to herbivory, an increase in FRO activity in response …

Antibiotic Resistant Bacteria In Water Environments In Louisville, Kentucky., Amy Priest

College of Arts & Sciences Senior Honors Theses

Antibiotic resistant bacterial strains are an increasing problem, particularly in clinical health care settings. As a result, bacterial infections are becoming increasingly challenging to treat with more cases becoming life threatening. Aquatic environments facilitate microbial diversity and the transfer of genetic elements and thus may serve as a reservoir for antibiotic resistant microbes. Human misuse of antibiotics may further facilitate the spread of resistance in water environments. With little known about the bacteria communities in local water environments, this study aimed to learn more about these populations through the following aims: 1) identify the microbial community composition from water environments …

Photonic Tools For Advanced Sensing And Imaging At The Nanoscale., Jafar Hamed Ghithan

Electronic Theses and Dissertations

This dissertation reports a novel bio-sensing strategy based on single-mode, electro-active, integrated optical waveguide (SM-EA-IOW) platforms. It also reports the development of a super-resolved far-field optical imaging tool to enable optical, electronic, and spectroelectrochemical investigations at the nanoscale. SM-EA-IOW platforms with its outstanding sensitivity for spectroelectrochemical interrogation was combined with a sandwich bioassay for the development of a novel immunosensing based strategy for label-free detection of infectious pathogens. The strategy begins with the functionalization of the electroactive waveguide surface with a capturing antibody aimed at a specific target analyte. Once the target analyte is bound to the photonic interface, it …

Vinyl Chloride Enhances Diet-Induced Liver Injury Via Metabolic Dyshomeostasis : Critical Role Of Mitochondria., Anna L. Lang

Electronic Theses and Dissertations

Background. Vinyl chloride (VC) is an environmental toxicant and has been shown to be directly hepatotoxic at high exposures. However, recent studies suggest low-level toxicant exposure can cause subtle changes to the liver. Given the high prevalence of non-alcoholic fatty liver disease (NAFLD) in the United States, it is important to determine the impact of low-level toxicant exposure on the progression of underlying liver injury when combined with other factors. Therefore, the overarching goal of this dissertation was to develop a model of VC co-exposure with high-fat diet (HFD) and to determine the mechanisms by which VC contributes to the …

The Effects Of Habitat And Connectivity On Tropical Ant Ecology And Behavior., Benjamin Jacob Adams

Electronic Theses and Dissertations

This dissertation explores the role that physical connections among and within habitats play in determining the local diversity and behaviors of cursorial organisms. Understanding the processes that regulate local community assembly and that contribute to the maintenance of species diversity is a cornerstone of community ecology. Ants are a useful model for studies of local communities because they are abundant and fulfill a variety of ecological roles. Chapter one of the dissertation examines the how lianas (woody vines) function as connective structures among tree crowns and how these connections affect arboreal ant community structure within a tropical forest canopy. Trees …

Characterization Of Type Ii Toxin Anti-Toxin Systems In Aggregatibacter Actinomycetemcomitans., Blair W. Schneider

Electronic Theses and Dissertations

Microbes express many protective mechanisms in response to environmental stress. Toxin/anti-toxin systems encode a biologically active toxin and a labile anti-toxin that inhibits the toxin’s activity. These systems are known to contribute to persister cell and biofilm formation. A. actinomycetemcomitans thrives in the complex oral microbial community and is subjected to continual environmental flux. Little is known regarding the presence and function of TA systems in this organism or their contribution survival in the oral environment. Using BLAST searches and other informatics tools, we identified 11 intact TA systems that are conserved across all seven serotypes of A. actinomycetemcomitans and …