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Deep Brain Stimulation And Its Effects On Parkinson Disease Spatiotemporal Gait Parameters., Greydon Gilmore

Electronic Thesis and Dissertation Repository

Subthalamic (STN) deep brain stimulation (DBS) alleviates common appendicular PD symptoms, such as: tremor, rigidity and bradykinesia. However, the effect STN-DBS has on modulating axial gait features has not been properly quantified objectively. The purpose of the present thesis was to investigate the role STN-DBS plays in modulating specific gait features such as pace, asymmetry, variability, rhythm and postural control. It is hypothesized that axial gait function is regulated predominantly by non-dopaminergic control systems. In the acute immediate post-operative phase a surgical effect, named the microlesion effect (MLE), is thought to produce a transient improvement of appendicular and axial symptoms. …

Feasibility Of Using Arterial Spin Labeling For Detecting Longitudinal Changes In Cerebral Blood Flow, Tracy Ssali

Electronic Thesis and Dissertation Repository

The ability of the perfusion MRI technique, arterial spin labeling (ASL), to quantify cerebral blood flow (CBF) makes it attractive for longitudinal studies of changes in brain function, such as those related to chronic pain. However, ASL's poor spatial resolution makes image alignment between sessions difficult, leading to increased variance and greater Type-I errors. In addition, variability due to differences in basal blood flow between sessions and confounding effects such as the arterial transit time (ATT) have the potential to reduce reproducibility over time. The focus of this thesis is to investigate the ability of ASL to detect long-term changes …

Iron Acquisition Mechanisms And Their Role In Staphylococcus Aureus Survival And Virulence, Jessica R. Sheldon

Electronic Thesis and Dissertation Repository

To microbes and humans alike, iron is both essential, and potentially toxic, where homeostatic concentrations must be stringently maintained. Within the iron-restricted host, the survival and proliferation of microbial invaders is contingent upon exploiting the host iron pool. Staphylococcus aureus is a formidable pathogen, whose success is partly attributable to its multiple, and often redundant mechanisms for acquiring iron. A decade of research in staphylococcal iron acquisition has identified several uptake mechanisms, including, but not limited to, the elaboration of high-affinity iron scavenging siderophores (staphyloferrins A (SA) and B (SB)) and the expression of an iron-regulated surface determinant (Isd) pathway …

Interdomain Interactions Of The Transactive Response Dna Binding Protein 43 Kda (Tdp-43), Karen M. Dunkerley

Electronic Thesis and Dissertation Repository

Transactive response DNA binding protein, 43 kDa (TDP-43) is 416-residue RNA processing and transport protein, observed in insoluble cytoplasmic aggregates within affected neurons in neurodegenerative diseases. TDP-43 has three domains: the N-terminal (N), RNA-binding (R) and unstructured C-terminal domains (G). Unstructured domains often form intramolecular interactions regulating other domains; our goal was to determine if such an interaction occurs in TDP-43. In Far Western blots, tagged NR was observed to bind to G. A 10 residue C-terminal truncation of G virtually abolished binding and introduction of phosphomimetics at Ser409/Ser410 also reduced binding. Sedimentation velocity ultracentrifugation with tagged NR and G …

Chemical Biology Approaches To Investigate The Activity And Substrate Specificity Of Protein Kinase Ck2, Michelle A. Gabriel

Electronic Thesis and Dissertation Repository

Protein kinase CK2 is a constitutively active, acidophilic protein serine/threonine kinase with an extensive array of protein substrates that have been implicated in the regulation of many cellular events including those that maintain the delicate balance between proliferation and survival. Although numerous substrates of CK2 have been identified, bioinformatic analysis predicts that 20% of the phosphoproteome can be attributed to CK2, suggesting that our understanding of CK2 is greatly underappreciated. Not surprisingly, CK2 levels are elevated in multiple cancers, and therapeutics targeting CK2 are in development. In order to realize the full potential of these therapies, it is essential to …

Hyperpolarized 129xe Magnetic Resonance Imaging Of Radiation-Induced Lung Injury, Ozkan Doganay

Electronic Thesis and Dissertation Repository

Lung cancer is the largest contributor to cancer-related mortality worldwide. Only 20% of stage III non-small cell lung cancer patients survive after 5-years post radiation therapy (RT). Although RT is an important treatment modality for lung cancer, it is limited by Radiation-Induced Lung Injury (RILI). RILI develops in two phases: (i) the early phase (days-weeks) referred to radiation pneumonitis (RP), and (ii) the late phase (months). There is a strong interest in early detection of RP using imaging to improve outcomes of RT for lung cancer. This thesis describes a promising approach based on ¹²⁹Xe gas as a contrast …

Cardiomyocyte Polarity And Embryonic Heart Development: Role Of Rac1, Carmen Leung

Electronic Thesis and Dissertation Repository

Congenital heart defects (CHDs) are the most common human birth defect and the leading cause of death from a birth defect in the first year of life. Thus, a further understanding of the mechanisms underlying CHDs, which could lead to improved diagnosis and treatment, is crucial. The small GTPase, Rac1, acts as a pleiotropic effector of numerous cellular processes; however, little is known about its role in embryonic heart development. The aim of this thesis was to investigate the role of Rac1 signaling in cardiac development. Using the Cre/loxP system, mouse models with an anterior second heart field (SHF) or …

The Effects Of Fatigue On The Reactive Agility Test: Looking At The Difference Between Normal Game Play And The Hurry-Up Offense In Football Game Simulations, Kristine E. Walker

Electronic Thesis and Dissertation Repository

Purpose: The purpose of this study was to assess the effects of fatigue on performance of the Reactive Agility Test (RAT) by University Football players. This test assesses the athlete’s ability to change direction in response to a visual stimulus, somewhat like responding to the actions of an opponent in a game. Two fatiguing conditions were compared, simulations of normal game play and hurry-up offense in football. Methods: Following a warm-up and baseline RAT testing the athletes performed 10 high intensity, sprints on a specialized treadmill, with a 1:5 work to rest ratio to simulate regular game pace. This was …

Light Up The Fly: Drosophila As A Non-Social Model In Insect Sociobiology, Alison L. Camiletti

Electronic Thesis and Dissertation Repository

Eusocial breeding systems are characterized by a reproductive division of labour. For many social taxa, the queen signals her fecundity to her daughters via a pheromone, which renders them sterile. Solitary insects, in contrast, lack social organization and their personal reproduction is not regulated by social cues. Despite these radically different breeding habits between these two taxa, one prediction from sociogenomic theory is that eusocial taxa evolved their complex caste system through co-option of pathways already present in solitary ancestors. In this thesis, I present a series of comparative experiments that provide support for these conserved genes and gene pathways …

Evolution Of Mobile Promoters In Prokaryotic Genomes., Mahnaz Rabbani

Electronic Thesis and Dissertation Repository

Mobile genetic elements are important factors in evolution, and greatly influence the structure of genomes, facilitating the development of new adaptive characteristics. The dynamics of these mobile elements can be described using various mathematical and statistical models. In this thesis, we focus on a specific category of mobile genetic elements, i.e. mobile promoters, which are mobile regions of DNA that initiate the transcription of genes. We present a class of mathematical models for the evolution of mobile promoters in prokaryotic genomes, based on data obtained from available sequenced genomes. Our novel location-based model incorporates two biologically meaningful regions of the …

Laminar Fmri In Auditory Cortex At 7t, Jacob Jl Matthews

Electronic Thesis and Dissertation Repository

Auditory cortex is involved in the perception, attention, memory and imagery of sounds. Neuroimaging has been a rich source of information on which cortical areas are recruited for different tasks. However, a more detailed understanding has been confined to animal studies using invasive imaging modalities, and high-resolution functional descriptions of auditory cortex, including columnar/laminar specific activity, topographical organization within layers, and the way these representations transfer between processing structures remain poorly understood in humans. We present 7T fMRI as a non-invasive tool for high-resolution functional imaging of human auditory cortex on the laminar scale. We describe MATLAB tools for optimizing …

Application Of 3d Printing Technology In Porous Anode Fabrication For Enhanced Power Output Of Microbial Fuel Cells, Bin Bian

Electronic Thesis and Dissertation Repository

Microbial fuel cells (MFCs) are widely researched for application in wastewater treatment. However, the current anodes used in MFCs often suffer from high fabrication cost and uncontrollable pore sizes. In this thesis, three-dimensional printing technique was utilized to fabricate anodes with different micro pore sizes for MFCs. Copper coating and carbonization were applied to the printed polymer anodes to increase the conductivity and specific surface area. Voltages of MFCs with various anodes were measured as well as other electrochemical tests such as linear sweep voltammetry and electrochemical impedance spectroscopy. 3D copper porous anode produced higher maximum voltages and power densities …

A Unified Framework For The Prioritization Of Variants Of Uncertain Significance In Hereditary Breast And Ovarian Cancer Patients, Natasha G. Caminsky

Electronic Thesis and Dissertation Repository

A significant proportion of hereditary breast and ovarian cancer (HBOC) patients receive uninformative genetic testing results, an issue exacerbated by the overwhelming quantity of variants of uncertain significance identified. This thesis describes a framework where, aside from protein coding changes, information theory (IT)-based sequence analysis identifies and prioritizes pathogenic variants occurring within sequence elements predicted to be recognized by proteins involved in mRNA splicing, transcription, and untranslated region binding and structure. To support the utilization of IT analysis, we established IT-based variant interpretation accuracy by performing a comprehensive review of mutations altering mRNA splicing in rare and common diseases.

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Determining Attention Deficits In Mouse Models Of Alzheimer’S Disease Using Touchscreen Systems, Talal Masood

Electronic Thesis and Dissertation Repository

Behavioural testing in mouse models of Alzheimer’s disease (AD) suffers from lack of standardization and reproducibility issues between laboratories. In order to solve this, a touchscreen system has been developed for mice based on the CANTAB. There are several cognitive dysfunctions that occur due to AD, including deficits in attention that can be tested using the touchscreens. In this study, we tested two mouse models of familial AD (5xFAD and 3xTG) with mutations that lead to an accelerated rate of amyloidosis. Both male and female mice were tested at two separate locations in order to test for the reproducibility of …

Isolation And Characterisation Of Relaxed Specificity I-Tevi Nuclease Domain Mutants, Alexander C. Roy

Electronic Thesis and Dissertation Repository

Engineering nucleases is important to the advancement of genetic engineering and gene therapy approaches. Engineering requires a knowledge of which residues are contributing to each function of the nuclease. The residues which contribute to cleavage specificity of the I-TevI nuclease domain (ND) are unknown. I suspect that some of these contributions derive from the ND, thus my null hypothesis is that mutation of the ND will not alter the substrates this enzyme can cut. I have mutagenised the I-TevI nuclease domain and using directed evolution I have isolated mutations which were characterised in vivo and in vitro. These mutations permit …

Molybdenum And Iron Interactions As Micronutrients For Growth Of A Freshwater Cyanobacterium, Microcystis Aeruginosa, Yan Xu

Electronic Thesis and Dissertation Repository

The cyanobacterium M. aeruginosa is an important bloom former in freshwater environments. We investigated the growth, photosynthesis and toxin contents of two toxic strains of M. aeruginosa, CPCC 299 and CPCC 300, under a combination of nitrogen supply (nitrate or ammonium) and depleted or replete Molybdenum (Mo) and/or Iron (Fe) concentrations. When Mo and Fe were supplied at growth-replete levels, M. aeruginosa grew equally well on nitrate and ammonium. Reducing Fe dramatically reduced growth rate efficiency when the cells were supplied with nitrate, but not with ammonium. In contrast, the removal of Mo from the medium did not impair …

Quinone Reductase 2 Is A Flavin Redox Switch, Kevin Ka Ki Leung

Electronic Thesis and Dissertation Repository

Quinone reductase 2 (NQO2) is a mammalian enzyme that catalyzes the reduction of quinone using an unusual co-substrate, dihydronicotinamide riboside (NRH). In addition, NQO2 has a secondary function, which is to modulate the 20S proteasomal degradation of p53 in a redox-dependent manner. This alternate function has been characterized in its sister enzyme quinone reductase 1 (NQO1) and yeast quinone reductase Lot6p, but relatively few studies have investigated the role of NQO2 beyond quinone catalysis. From studies of Lot6p, it was proposed that quinone reductases could be categorized as flavin redox switches. In this thesis, the how NQO2 functions as a …

Structure-Function Relationship Of The Brain: A Comparison Between The 2d Classical Ising Model And The Generalized Ising Model, Pubuditha M. Abeyasinghe

Electronic Thesis and Dissertation Repository

There is evidence that the functional patterns of the brain observed at rest using fMRI are sustained by a structural architecture of axonal fiber bundles. As neuroimaging techniques advance with time, the relationship between structure and function has become the object of many studies in neuroscience. As recently suggested, the well defined connectivity structure found in the brain can be used to understand the self organization of the brain at rest, as well as to infer the functional connectivity patterns of the brain using different models, such as the Kuramoto model which studies synchronization, and the 2-dimensional classical Ising model, …

Wnt Signalling During F9 Cell Differentiation, Gregory M. Golenia

Electronic Thesis and Dissertation Repository

Mouse F9 cells differentiate into primitive endoderm (PrE) when treated with retinoic acid (RA) and this is accompanied by the upregulation of Wnt6 and activation of the canonical WNT/β-catenin pathway. Previous studies have demonstrated the necessity of β-catenin-TCF/LEF transcription for primitive endoderm differentiation, however the Frizzled (FZD) receptor responsible for binding WNT6 and activating the canonical WNT pathway is not known. It was hypothesized that FZD7 is responsible for binding and transducing the WNT6 signal. Fzd7 mRNA was detected in undifferentiated and primitive endoderm cells, and its expression does not change significantly in response to RA. Moreover and contrary to …

Characterization Of Fatty Acid Resistant Staphylococcus Aureus Mutants Containing Snps In Cvfa, Melissa N. Loyzer

Electronic Thesis and Dissertation Repository

Upon colonization, Staphylococcus aureus must withstand the actions of many host defense mechanisms, including the unsaturated free fatty acids (uFFAs) secreted in sebum. Linoleic acid, a representative uFFA, is toxic to S. aureus at concentrations ≥50 µM; however, we selected for mutants capable of growing at elevated concentrations of linoleic acid. Five mutants had single nucleotide polymorphisms (SNPs) in the cvfA gene encoding an RNase that is a component of the RNA degradosome, and expression of the SNP-containing cvfA genes from a plasmid engendered S. aureus with high level resistance to linoleic acid. The SNPs were located within a region …

Characterizing The C-Terminal Region Of Human Adenovirus E1a: An Undiscovered Country, Michael J. Cohen

Electronic Thesis and Dissertation Repository

Human Adenovirus (HAdV) E1A is the first protein expressed during viral infection. The primary function of E1A is to reprogram the cell for viral replication, but it is additionally capable of transforming primary rodent cells in co-operation with other oncogenes such as HAdV E1B. Despite extensive study, little is known about the function and cellular targets of the C-terminal region of E1A. Importantly, this region is required for the transforming ability of E1A with E1B, but can also suppress transformation with Ras. Previous studies showed that interaction with the C-terminal Binding Protein (CtBP) plays a role in both functions described …

Reactions Between Zinc Metallothionein And Carbonic Anhydrase, Tyler B. J. Pinter

Electronic Thesis and Dissertation Repository

More than 25% of proteins require metal ion cofactors for structure or function. The interactions between metalloproteins have largely been overlooked, though these interactions ultimately govern metal localization and control metal ion homeostasis. Mammalian metallothionein (MT) is a small, cysteine-rich metalloprotein that binds numerous metal ions per protein strand. Up to seven divalent metals, such as zinc or cadmium, are wrapped into a clustered two-domain structure. This unusually high metal content places MT as an attractive candidate for studying interactions with other metal-binding proteins. This present study investigates the metal transfer reactions between MTs and other metalloproteins, using carbonic anhydrase …

Degrees Of Damage: Quantifying Male Vs. Female Exercise-Induced Muscle Damage Through Magnetization Transfer Ratios, Nicholai Michael Clausius Crawford

Electronic Thesis and Dissertation Repository

No direct, quantitative, and non-invasive markers presently exist to assess exercise-induced muscle damage (EIMD). However, magnetization transfer ratios (MTR), an emerging measurement quantified via magnetic resonance imagery, provide more direct indication of muscle integrity following EIMD. This study compares and correlates the temporal pattern of the MTR to alternative indirect markers of EIMD in male vs. female populations, and subsequently establishes whether there are sex differences in biochemical activity during recovery. The antioxidant properties of estrogen hypothetically minimize muscle trauma, maintain membrane stability, and limit swelling resulting in heightened tissue integrity and resilience to EIMD. Six males and three females …

Exploring Cross-Sectional Associations Between Unhealthy Food Outlet Exposure And Bmi Z-Score In Elementary School Children In London, Canada, Krista Cook

Electronic Thesis and Dissertation Repository

The food environment has been implicated in the continuing epidemic of childhood obesity in Canada. The purpose of this thesis is to examine associations between the food environment, childhood weight, and unhealthy diets using data collected by the Spatial Temporal Environmental and Activity Monitoring (STEAM) project conducted among children (N=852) aged 9 to 14 years in Southwestern Ontario between 2010 and 2013. Global Positioning System (GPS) monitors and Geographic Information Systems (GIS) were used to determine the time children spent within 100m of an unhealthy food outlet on weekdays. Structural equation modeling was used to assess the effect of exposure …

Clinical And Experimental Importance Of Circulating Tumor Cells In Prostate Cancer, Lori Lowes

Electronic Thesis and Dissertation Repository

Prostate cancer (PCa) remains a leading cause of death in men, primarily due to ineffective treatment in the metastatic setting. During this phase of PCa, circulating tumor cells (CTCs) are shed into the bloodstream and their presence and number are important in patient prognosis. The CellSearch® system (CSS) is the only U.S. Food and Drug Administration (FDA) and Health Canada approved instrument for detection of CTCs, making it the current clinical gold standard in CTC technology. Although the CSS provides a minimally invasive means of patient monitoring in the metastatic setting, little is known about the role of CTCs in …

A Plant-Made Vaccine Candidate To Protect Ruminants Against Shiga Toxin-Producing Escherichia Coli, Sean Miletic

Electronic Thesis and Dissertation Repository

Shiga toxin-producing Escherichia coli (STEC) are enteropathogens colonizing the digestive tracts of humans and animals worldwide. STEC are shed in the manure of cattle and frequently contaminate beef products, vegetables, and drinking water. Immunizing cattle herds against STEC is a promising strategy to reduce STEC colonization in cattle and therefore decrease contamination in the food supply. The goal of this project is to produce a plant-made vaccine to protect ruminants against STEC. Several recombinant proteins were designed as vaccine candidates and expressed transiently in Nicotiana benthamiana and transplastomically Nicotiana tabacum. One vaccine candidate, an E. coli secreted protein A (EspA) …

Neural And Behavioural Responses To Rewards And Losses In Early Development: A Functional Magnetic Resonance Imaging Study, Niki Hosseini-Kamkar

Electronic Thesis and Dissertation Repository

Functional magnetic resonance imaging (fMRI) was used to investigate the neural and behavioural correlates of learning from rewards and losses in children. Greater blood-oxygen-level dependent (BOLD) responses in the ventral striatum (VS) and the ventromedial prefrontal cortex (VMPFC) were found when participants received rewards compared to when they missed out on an opportunity to receive rewards. In contrast, greater BOLD responses in the anterior insula (AI) and the anterior cingulate cortex (ACC) were found when participants received losses compared to when they avoided losing. The BOLD response to rewards in the VS and VMPFC correlated positively with the tendency to …

Inferring Plastid Metabolic Pathways Within The Nonphotosynthetic Free-Living Green Algal Genus Polytomella, Sara Asmail

Electronic Thesis and Dissertation Repository

The advent of photosynthesis facilitated the evolution of aerobic life on Earth. However, species such as Prototheca wickerhamii and Plasmodium falciparum, among many others, have lost photosynthesis and opted for a free-living/parasitic lifestyle. Despite this loss, these species have retained the plastid for its metabolic pathways, without which they would die. Polytomella is a nonphotosynthetic free-living alga, closely related to the photosynthetic model organism Chlamydomonas reinhardtii, and has been shown to lack a plastid genome. I set out to determine Polytomella plastid metabolic pathways using bioinformatics to look for mRNA and DNA homologous sequences matching pathway enzymes in model organisms. …

Characterization Of The Atsr/Atst Global Regulatory Pathway In Burkholderia Ceocepacia, Maryam Khodai-Kalaki

Electronic Thesis and Dissertation Repository

Phosphorylation cascades governed by two-component signal transduction systems provide key signalling mechanisms in bacteria, simple eukaryotes and higher plants, allowing them to translate signals into adaptive responses. These regulatory pathways consist of a transmembrane sensor protein that responds to an environmental cue leading to autophosphorylation, followed by the transfer of the phosphate to a cytoplasmic response regulator. Here, I study AtsR, a membrane-bound hybrid sensor kinase of Burkholderia cenocepacia, that negatively regulates quorum sensing related virulence factors such as biofilm, type 6-secretion and protease secretion. B. cenocepacia is a Gram-negative opportunistic pathogen which causes severe, chronic respiratory infections in …

Engineered Cx26 Variant Established Functional Heterotypic Cx26/Cx43 And Cx26/Cx40 Gap Junction Channels, Levent Berk Karademir

Electronic Thesis and Dissertation Repository

Two hexameric connexin hemichannels dock together to from a whole gap junction (GJ) channel. The mechanisms of docking specificity in forming homotypic and heterotypic GJ channels are not fully clear. To reveal the key differences between Cx26 and Cx43 (or Cx40) in their docking residues, we aligned and analyzed ten well studied connexin sequences. Five of them are docking compatible with Cx26 and the rest (including Cx43 and Cx40) are not. According to Cx26 crystal structure at the docking interface, we identified two putative docking residues on the second extracellular domain (E2) that are well conserved within docking compatible connexins, …