Life Sciences Commons^™

Characterization Of The Catalytic Ck2 Subunits With Substitutions At Residues Involved In Inhibitor Binding, Paul Desormeaux

Electronic Thesis and Dissertation Repository

CK2 is a constitutively active, ubiquitously expressed and pleiotropic serine/threonine protein kinase that is implicated in many cellular functions including tumorigenesis. CK2 has two catalytic subunits, CK2a and CK2a’, that carry out its function in the cell. Previous studies have indicated that inhibitor-refractory mutants have been effective in recovering residual CK2 activity, in the presence of inhibitors, when compared to wild type CK2. Based on these observations, inhibitor-refractory mutants were created for both CK2a and CK2a’ and tested with various concentrations with two CK2-specific inhibitors, CX-4945 and inhibitor VIII. The CK2a triple mutant (V66A/I174A/H160D) was tested in inducible U2OS Flp-In …

Effect Of Terminal Haptic Feedback On The Sensorimotor Control Of Visually And Tactile-Guided Grasping, Shirin Davarpanah Jazi

Electronic Thesis and Dissertation Repository

When grasping a physical object, the sensorimotor system is able to specify grip aperture via absolute sensory information. In contrast, grasping to a location previously occupied by (no-target pantomime-grasp) or adjacent to (spatially dissociated pantomime-grasp) an object results in the specification of grip aperture via relative sensory information. It is important to recognize that grasping a physical object and pantomime-grasping differ not only in terms of their spatial properties but also with respect to the availability of haptic feedback. Thus, the objective of this dissertation was to investigate how terminal haptic feedback influences the underlying mechanisms that support goal-directed grasping …

Contribution Of The Primate Frontal Cortex To Eye Movements And Neuronal Activity In The Superior Colliculus, Tyler R. Peel

Electronic Thesis and Dissertation Repository

Humans and non-human primates must precisely align the eyes on an object to view it with high visual acuity. An important role of the oculomotor system is to generate accurate eye movements, such as saccades, toward a target. Given that each eye has only six muscles that rotate the eye in three degrees of freedom, this relatively simple volitional movement has allowed researchers to well-characterize the brain areas involved in their generation. In particular, the midbrain Superior Colliculus (SC), is recognized as having a primary role in the generation of visually-guided saccades via the integration of sensory and cognitive information. …

The Role Of Gaba Signalling In Lung Macrophage Immune Response, Jacob W. Poirier

Electronic Thesis and Dissertation Repository

Lung macrophages (LMϕs) play a key role in pulmonary innate immunity. They polarize into different phenotypes adapting to the needs of the immediate pulmonary environment. Studies in our laboratory suggest that murine LMϕs are endowed with an autocrine gamma-aminobutyric acid (GABA) signaling system. My honors thesis study found that antagonizing the autocrine GABA signaling in alveolar macrophages (AMϕs) increased secretion of the M1 cytokine tumor necrosis factor-alpha (TNF-α), suggesting a role for GABA signaling in immune response. This project explored whether GABA signaling plays a role in LMϕ polarization. Results from this study confirmed that bacterial toxin lipopolysaccharide (LPS) and …

Using Mutual Information To Reprogram Dna Specificity Of Laglidadg Endonucleases, Marcon Laforet

Electronic Thesis and Dissertation Repository

A systematic approach to reprogram protein-DNA interactions has yet to be discovered. This study investigates the ability of co-variation analyses to identify potential protein-DNA contacts that regulate specificity. Here, 27 LAGLIDADG Homing Endonucleases (LHEs) and their 22-basepair DNA targets were collated into a Multiple Sequence Alignment (MSA) that was subjected to pairwise co-variation calculations. Using the LHE I-OnuI as a reference, an amino acid-DNA pair, lysine (K) 231 and adenine +3, generated the highest score. To test if the K231/A3 score was biologically relevant we tested protein mutants for altered nuclease specificity at +3 DNA point mutants. Randomizing the 231 …

Abe Fermentation From Low Cost Substrates, Kai Gao

Electronic Thesis and Dissertation Repository

The high cost of substrate and product inhibition in the fermentation broth remains two major problems associated with bio-butanol production. This thesis aims to solve these problems by examining abundant lignocellulosic biomass as potential feedstocks and exploring novel substrates such as carbohydrates derived from microalgae for ABE fermentation. The commonly observed toxic effect after pretreatment of lignocelluslosic biomass was removed by resin adsorption, where the resin could also serve as an in-situ butanol recvoery devices.

Corn cobs (an agricultural waste), switchgrass (an energy crop) and phragmites (an invasive plant in North America) were investigated as substrates for ABE fermentation by …

A Model-Based Test Of The Efficacy Of A Simple Rule For Predicting Adaptive Sex Allocation, Joshua D. Dunn

Electronic Thesis and Dissertation Repository

The division of resources between male and female reproductive function is defined as sex allocation. The usefulness of simple rules to predict adaptive sex-allocation decisions has been a contentious topic. Simple rules are difficult to apply when the biological details of the life cycle are complex, as is the case in many vertebrates. We build a mathematical-computational model to investigate the usefulness of a simple rule that predicts adaptive sex-allocation decisions. We find that the simple rule is a better predictor of adaptive sex-allocation decisions when more features of an organism's life cycle are assumed to evolve. Even though the …

The Neuroprotective Effects Of Endurance Training On The Aging Brain, Katelyn Norton

Electronic Thesis and Dissertation Repository

Dysregulation of autonomic control often develops with advancing age, favoring a chronic state of heightened sympathetic outflow with parasympathetic withdrawal. However, the mechanisms of this age-related autonomic impairment are not known and may relate to alterations in brain structure (e.g. cortical atrophy) and/or altered neural function, particularly in regions related to the cortical autonomic network, namely, the medial prefrontal cortex (MPFC), insula cortex (IC), and hippocampus (HC). Exercise exerts beneficial effects on brain structure and, in the case of cognition, neurologic function; however, how exercise affects regions of the brain related to autonomic function are not known. This thesis tested …

Gait Real-Time Analysis Interactive Lab: Reliability And Validity Of Knee Angles And Moments In Patients With Knee Osteoarthritis, Ryan Pinto

Electronic Thesis and Dissertation Repository

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Abstract

Objectives: 1) Estimate test-retest reliability of knee angles and moments during gait in patients with knee osteoarthritis (OA) using the Gait Real-Time Analysis Interactive Lab (GRAIL); 2) Examine concurrent validity of knee angles and moments using the GRAIL and overground system (gold standard); and 3) Examine known-groups validity of knee angles and moments in patients with knee OA and healthy ontrols.

Methods: Patients and controls walked using both systems to produce knee angle and moment waveforms during stance, enabling discrete measure comparisons. atients completed a second session within one week.

Results: Intraclass correlation coefficients ranged from 0.52-to-0.93 for …

Indicator Amino Acid Derived Estimates Of Dietary Protein Requirement In Exercise-Trained Individuals, Arash Bandegan

Electronic Thesis and Dissertation Repository

Despite a number of nitrogen balance (NB) studies indicating increased dietary protein needs in Endurance (ET) and strength (ST) trained athletes, the Institute of Medicine (2005) has concluded, based largely on methodological concerns, that “no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise”. Indicator amino acid oxidation method (IAAO) has been recently used for determination of protein requirement in humans. This method is based on the concept that when one indispensable amino acid (AA) is deficient for protein synthesis, then all other AA, including the indicator, will be considered excess and oxidized. With increasing intakes …

An Investigation Of The Plant Growth Promoting Abilities Of Pseudomonas Fluorescens Uw4 Under Toxic Metal Stress, Joshua J. Frank

Electronic Thesis and Dissertation Repository

I investigated plant-microbe-metal interactions under metal stress. In theory, plant growth promoting rhizobacteria (PGPR) promote plant growth by reducing stress ethylene and synthesizing indole-3-acetic acid (IAA). The putative PGPR Pseudomonas fluorescens UW4 and a mutant strain that lacked an enzyme critical to the reduction of plant ethylene were studied to determine if they could promote Arabidopsis thaliana growth under cadmium and copper stress conditions. Both strains of P. fluorescens UW4 adhered to roots and synthesized IAA, and the wild-type lowered metal stress-induced ethylene in Arabidopsis, but neither strain enhanced plant growth. Wildtype P. fluorescens UW4 and its mutant had …

Telomere Length Variation In Preschool Children: Associations With Chronic Family Stress, Maternal Depression, And Cortisol Reactivity, Aditi Thakur

Electronic Thesis and Dissertation Repository

Telomeres are repetitive nucleotide repeats of TTAGGG sequences located at the two ends of each chromosome. Telomeres protect DNA from degradation and maintain genomic stability. Shorter telomeres are implicated in different diseases and disorders including psychiatric disorders. I measured buccal cell telomere length (TL) in 384 pre-school children (3-4 years), from Southwestern Ontario using monochrome multiplex qPCR method. I assessed the associations between TL and family, child-specific variables. I did not find a significant correlation between TL and maternal depression, chronic family stress, or age and sex of the children. However, I found a significant positive correlation between TL and …

Using An Aerial Drone To Examine Lateral Movement In Sweep Rowers, Joseph S. Munn

Electronic Thesis and Dissertation Repository

Rowing is a sport that is performed on the water, because of this there are many challenges associated with studying rowing. The primary challenges are an inability to control the environment and limitations with the equipment that can be used to collect data on the water. In order to try and overcome some of these challenges an aerial drone fitted with a high resolution camera was used to examine an understudied element of the rowing stroke, lateral movement in sweep rowers. Oar and shoulder angles and lateral movement of the shoulders and hands were calculated and compared between five different …

Evaluating The Interaction Between Buckwheat, Fagopyrum Esculentum (Polygonaceae) And Wireworm Agriotes Sputator L. (Coleoptera: Elateridae), Yeritza L. Bohorquez

Electronic Thesis and Dissertation Repository

Laboratory experiments were carried out to determine if buckwheat, Fagopyrum esculentum, produces phytochemicals that act as deterrents, anti-feedants, or toxins against Agriotes sputator wireworms. Choice assays were conducted to test the attractiveness of germinating, branching and flowering buckwheat, red spring wheat (Triticum spp) and island barley (Hordeum vulgare) to the larvae. There was no evidence that the wireworms were deterred by buckwheat and the germinating stage of all three crops was the most attractive. Twenty-one day, no choice feeding assays were conducted to determine change in mass and mortality of A. sputator larvae when fed buckwheat or …

First Major Appearance Of Brachiopod-Dominated Benthic Shelly Communities In The Reef Ecosystem During The Early Silurian, Cale A.C. Gushulak

Electronic Thesis and Dissertation Repository

The early Silurian reefs of the Attawapiskat Formation in the Hudson Bay Basin preserved the oldest record of major invasion of the coral-stromatoporoid skeletal reefs by brachiopods and other marine shelly benthos, providing an excellent opportunity for studying the early evolution, functional morphology, and community organization of the rich and diverse reef-dwelling brachiopods. Biometric and multivariate analysis demonstrate that the reef-dwelling Pentameroides septentrionalis evolved from the level-bottom-dwelling Pentameroides subrectus to develop a larger and more globular shell. The reef-dwelling brachiopods in the paleoequatorial Hudson Bay Basin were more diverse than contemporaneous higher latitude reef-dwelling brachiopod faunas, with ten distinct …

Multi-Gene Resistance To Neonicotinoids In The Colorado Potato Beetle, Leptinotarsa Decemlineata, Emine Kaplanoglu

Electronic Thesis and Dissertation Repository

The Colorado potato beetle, Leptinotarsa decemlineata, is a significant pest of potato, and its impact on agriculture is measured on a global scale. The beetle is mainly controlled by neonicotinoid insecticides, however, resistance development is a growing concern. Resistance to neonicotinoids is thought to involve elevated activity of detoxifying enzymes and xenobiotic transporters that break-down and excrete insecticide molecules. Here, using mRNA sequencing, I identified multiple detoxifying enzyme and xenobiotic transporter genes transcriptionally up-regulated in a neonicotinoid resistant strain of beetles. I then used RNA interference to knock down the transcript levels of the ten most promising genes in …

Iron Acquisition Strategies Employed By Staphylococcus Lugdunensis, Jeremy R. Brozyna

Electronic Thesis and Dissertation Repository

Iron is crucial for many cellular processes including DNA synthesis and respiration. The majority of iron in mammals is in heme within hemoproteins, inside cells, or transported through circulation by the glycoprotein transferrin, which constitutes the greatest iron source in serum. Limiting iron availability is an important facet of nutritional immunity to help prevent infection.

Staphylococcus lugdunensis is a human skin commensal and opportunistic pathogen capable of causing a variety of infections, including particularly aggressive endocarditis. It is an emerging pathogen with elevated virulence compared to other species of coagulase-negative staphylococci. The versatility of S. lugdunensis to infect multiple niches …

Constraining Kinematics During Single-Leg Squats And Step-Ups Can Reduce Quadratus Lumborum Activation And Facilitate Gluteal Activation, Shaylyn Kowalchuk

Electronic Thesis and Dissertation Repository

Increased quadratus lumborum activation and decreased gluteal activation may lead to lateral pelvic drop and increased hip adduction and internal rotation during single-leg exercises. These activation patterns and motions are associated with low back pain or lower extremity injuries. The purpose of this study was to evaluate if mechanically restricting hip adduction and internal rotation of the femur affected muscle activation. Twenty female track and field athletes performed single-leg squats and step-ups, and the quadratus lumborum, gluteus medius and maximus muscles activations were measured with surface electromyography. This study tested the hypothesis that mechanically restricted exercises would decrease quadratus lumborum …

The Cardiovascular Benefits Of Regular Exercise In Type 1 Diabetes Mellitus And The Risk Of Exercise-Induced Hypoglycemia, Matthew W. Mcdonald

Electronic Thesis and Dissertation Repository

Type 1 diabetes mellitus (T1DM) is associated with compromised glycemic control and a heightened risk for cardiovascular disease. The common treatment of T1DM with strict glycemic control through intensive insulin therapy can be problematic (weight gain, insulin resistance, hypoglycemia). Regular exercise is known to improve cardiovascular health, yet most individuals with T1DM remain sedentary, and identify the risk of exercise-induced hypoglycemia as a significant barrier. The investigation into the use of different forms of exercise (higher intensity, resistance) for preventing exercise-induced hypoglycemia in populations with T1DM has been promising, however, little work has investigated their cardiovascular benefit or whether the …

Insights Into Chibby's Structural Elements And Their Interplay In Wnt Signaling Protein-Protein Interactions, Ryan C Killoran

Electronic Thesis and Dissertation Repository

The Wnt/b-catenin signaling pathway is critical to embryonic development and adult tissue homeostasis. Mutations to Wnt signaling components can cause dysregulation of the pathway, leading to various human diseases such as cancer. The partially disordered protein Chibby (Cby) is a conserved nuclear protein that acts as an antagonist in the Wnt/b-catenin signaling pathway. Cby’s antagonism is accomplished via two mechanisms. First, by competing with the Tcf/Lef family of transcription factors, Cby abrogates the b-catenin-mediated transcription of Wnt signaling genes. Moreover, upon phosphorylation on serine 20 by the kinase Akt, Cby forms a complex with the protein 14-3-3 to facilitate the …

Modulating Parkin E3 Ubiquitin Ligase Activity Using Phospho-Ubiquitin Variants, Susanna George

Electronic Thesis and Dissertation Repository

Parkin is a Parkinson’s disease-linked E3 ubiquitin (Ub) ligase that promotes mitophagy by ubiquitination of mitochondrial outer membrane proteins. Phosphorylation of Ub at Ser65 by the PTEN-induced putative kinase 1 activates parkin. The role of other Ub phosphorylation sites and the associated kinases remain unknown. We optimized genetic code expansion to produce pure site-specfically phosphorylated Ub (pUb) variants (pUb^S7, pUb^S12, pUb^S20, pUb^S65) and investigated their activity in a key neurodegenerative pathway. Purification of pUb^S7 revealed a +3 frameshifted protein (Ub ∆7) that was successfully purified away from the pUb. Parkin was …

Is Online Motor Control Really Impaired In Parkinson's Disease?, Kate E. Merritt

Electronic Thesis and Dissertation Repository

Patients with Parkinson’s disease (PD) are thought to be selectively impaired in consciously-mediated online automatic motor control, whereas the ability to perform subconscious online adjustments remains intact. This present study evaluates the hypothesis that the previously alleged deficits in online motor control in PD are not due to the consciousness of the correction, but rather are attributable to aspects of the prior experimental designs disproportionately penalizing patients for PD-related bradykinesia. Here, we implemented a modified traditional double-step paradigm to investigate consciously-mediated online motor control in PD, in a manner that would be unconfounded by disease-related bradykinesia. Further, we investigated the …

Evaluation Of Mertk Evolution And Efferocytosis Signalling, Amanda L. Evans

Electronic Thesis and Dissertation Repository

The TAM (TYRO3, AXL, and MERTK) family of receptor tyrosine kinases allow phagocytes to engage in the phagocytic removal of apoptotic cells. Although all three members of the TAM family are structurally homologous and function in a similar fashion, both human genome-wide association studies and knockout mice models have demonstrated that MERTK is the critical member of the TAM family for maintaining homeostasis. In this thesis, an evolutionary analysis was used to provide insight into the function of MERTK. Selection analysis in primates unexpectedly revealed a high degree of recent positive selection in MERTK’s signal peptide and transmembrane domain, …

Decomposition Dynamics Under Climate Change Conditions In Boreal Peat, Rosa Del Giudice

Electronic Thesis and Dissertation Repository

Boreal peatlands currently act as carbon sinks, but are projected to become carbon sources under climate change. Shifts in plant community composition alongside increased decomposition rates are potential mechanisms precipitating this change. My objective was to determine the decomposition potential of different peatland plant litters (Sphagnum magellanicum (peat moss), Carex magellanica (graminoid) and Chamaedaphne calyculata (woody shrub)) during short-term (48 hour) leaching and microbial decomposition (20 week) phases. The 48-hour leaching experiment measured mass loss and leachate chemistry of litters grown under ambient and elevated CO₂, while the 20-week experiment measured heterotrophic respiration and mass loss of …

Cal And Magi Pdz Protein Regulation Of Crfr1 And 5-Ht2ar Trafficking And Signaling, Maha Mahmoud Hammad

Electronic Thesis and Dissertation Repository

PDZ (PSD95/Disc Large/Zona Occludens) domain-containing proteins are scaffolding proteins that play important roles in regulating the activity of G protein-coupled receptors. Corticotropin Releasing Factor Receptor 1 (CRFR1) and Serotonin 2A Receptor (5-HT_2AR) are two GPCRs that are commonly associated with mental disorders. Both receptors also contain a class I PDZ-binding motif at the carboxyl terminal tail. In the first chapter, we investigate the effects of CAL (CFTR-associated ligand) on regulating the trafficking and signaling of CRFR1. We demonstrate a role for CAL in inhibiting CRFR1 endocytosis, cell surface expression, and CRF-mediated ERK1/2 signaling via the CRFR1 PDZ-binding motif. …

Agaricomycetes Of Ontario Tallgrass Prairies, Christopher R. J. Hay

Electronic Thesis and Dissertation Repository

This study provides the first characterization of the Agaricomycetes of Ontario tallgrass prairies, assesses the influence of various environmental factors, and compares results of aboveground mushroom surveys with belowground high-throughput DNA sequencing. Overall, the Mycenaceae, Ceratobasidiaceae and Polyporaceae were the most abundant, and the Clavariaceae, Entolomataceae and Sebacinaceae the richest in species. Position along a transect (geographic region) was the primary factor differentiating Agaricomycete composition of sites whereas tillage history and soil organic carbon content were secondary. The Hygrophoraceae and Clavariaceae were associated with pristine sites, and Minimedusa spp. associated with tillage. The belowground method captured most of the minor …

The Differential Effects Of Connexin26 And Connexin43 In Modulating Epidermal Health In Response To Uv Injury, Katanya C. Alaga

Electronic Thesis and Dissertation Repository

Using two disease-linked connexin mutant mice that possess significantly reduced connexin function (Cx43^I130T/+ and Cx26^K14-S17F/+) this investigation is the first to address the roles of Cx26 and Cx43 in modulating epidermal health in response to UV radiation. Viable Cx26^K14-S17F/+ mice were successfully created in-house to express the mutant Cx26 S17F protein in keratinocytes and possess scaly skin, rapidly develop epidermal desquamation, and die soon after UV exposure. Conversely, Cx43^I130T/+ mice did not possess any skin abnormalities before or after UV exposure. We also identified that primary murine melanocytes are not homocellularly coupled and do not …

A Long-Term Neuroepigenomic Profile Of Prenatal Alcohol Exposure, Benjamin I. Laufer

Electronic Thesis and Dissertation Repository

Fetal Alcohol Spectrum Disorders (FASD) represent the largest preventable cause of cognitive deficits in the western world. The mechanism(s) of how prenatal alcohol exposure (PAE) results in FASD remain unknown. Towards this end, mouse models of PAE have successfully recreated endophenotypes that are characteristic of FASD. This doctoral thesis examines the long-term epigenomic alterations associated with PAE. I have examined both mice with PAE and human patients with FASD.

In the first set of experiments, mice with PAE and matched controls were raised to adulthood and then their whole brains were examined for alterations to gene expression, non-coding RNA (ncRNA) …

Glycosylation On Stromal Interaction Molecule-1 Ca2+ Sensing Region Enhances Store Operated Ca2+ Entry, Yoo Jung Choi

Electronic Thesis and Dissertation Repository

A major intracellular calcium (Ca²⁺) uptake pathway in excitable and non-excitable eukaryotic cells is store-operated Ca²⁺ entry (SOCE). Stromal interaction molecule-1 (STIM1) is the key regulator of SOCE and responds to changes in endoplasmic reticulum (ER)-stored Ca²⁺ through luminal sensing machinery composed of EF-hand and SAM domains (EFSAM). EFSAM can undergo N-glycosylation at Asn131 and Asn171 sites; however, the exact molecular and functional effects of N-glycosylation are unclear. By establishing a site-specific chemical approach to covalently linking glucose to EFSAM and subsequently examining EFSAM biophysical properties, I found that this modification enhances STIM1 activation …

Evolutionary History And Biological Regulation Of Cd93, Jack W D Blackburn

Electronic Thesis and Dissertation Repository

CD93 is a transmembrane C-type lectin expressed on myeloid, endothelial, and B cells. First identified as a developmental B cell marker and a phagocytic C1q receptor, little is known about the role and mechanism of CD93 in efferocytosis (the phagocytosis of apoptotic cells). CD93 knockout mice develop chronic inflammatory diseases characterized by a lack of efferocytosis such as atherosclerosis and a lupus-like autoimmune disease. In humans, a cleaved form of CD93 (sCD93) is elevated during inflammation and autoimmune responses, and CD93 polymorphisms are associated with enhanced susceptibility to atherosclerosis and lupus. Despite these clinical associations, no comprehensive bioinformatic analysis of …