Life Sciences Commons^™

Pdz Protein Regulation Of Β-Arrestin Recruitment And Gpcr Trafficking, Sarah Gupta

Electronic Thesis and Dissertation Repository

β-arrestins are versatile adaptor proteins that play a vital role in regulation of G protein coupled receptor (GPCR) trafficking and signalling properties. PDZ proteins have previously been shown to modulate β-arrestin2 recruitment and receptor internalization for many GPCRs including Corticotropin-Releasing Factor Receptor 1 (CRFR1), a receptor whose antagonists have been shown to demonstrate both anxiolytic- and antidepressant-like effects. Further characterization of the interplay between β-arrestins and PDZ proteins may aid in determining a potential mechanism for PDZ protein regulation of GPCR trafficking. Our findings suggest that PDZ proteins PSD-95, MAGI1, and PDZK1 complex with β-arrestin2 by interacting via the PDZ …

New Insights Into Signal Detection Of The Effects Of Exposures During Pregnancy, Fatma Etwel

Electronic Thesis and Dissertation Repository

There is inadequate information on the fetal safety of drugs during pregnancy for the majority of marketed drugs. It is challenging to examine the safety and efficacy of drugs during pregnancy due to the ethical issues of exposing unborn babies to these chemicals. It often takes many years before associations between a drug and its safety, efficacy, and toxicity in pregnancy can be established. This thesis will examine strategies in signal detection of the effects of drug exposures during pregnancy.

Meta-analyses have become useful in the area of clinical teratology. Observational studies provide the main source of information in these …

Evidence Of A Role For G Protein Signaling Modulator 3 In Cell Division, Drew C. Wallace

Electronic Thesis and Dissertation Repository

Components of G protein-mediated signaling are associated with positioning and orienting the mitotic spindle in the process of cell division. However, a functional role for G protein signaling modulator 3 (GPSM3) in cell division has yet to be defined. The purpose of this study was to investigate a potential role for GPSM3 in cell division. Vascular smooth muscle cells (VSMCs) from Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats, that are known to express GPSM3, were used as a model system. Here I report that GPSM3 mRNA and protein levels varied during different stages of the cell cycle in SHR VSMCs. …

The Association Between Oxidative Stress, Cellular Differentiation And Galectins In Human Promyelocytic Leukemia Cells (Hl-60), James R. Vinnai

Electronic Thesis and Dissertation Repository

Galectins are a group of β-galactoside-binding proteins involved in different cellular processes including stress responses and differentiation. The role and expression of galectins under oxidative stress and during neutrophilic differentiation was examined in HL-60 cells. Galectin gene (LGALS), and galectin protein expression were determined using RT-qPCR and immunoblotting, respectively. Neutrophilic differentiation was measured via a spectrofluorometric assay. DNA methylation and JNK signaling were investigated as galectin regulatory mechanisms. Menadione-induced oxidative stress, DMSO-induced differentiation, DNA hypomethylation and JNK signaling all promoted similar galectin expression profiles. Antioxidant N-acetylcysteine attenuated the menadione-induced galectin expression but only partially attenuated DMSO-induced galectin expression. …

Producing A Subunit Vaccine For Porcine Epidemic Diarrhea Virus, Zayn Khamis

Electronic Thesis and Dissertation Repository

Porcine epidemic diarrhea virus (PEDv) causes disease and mortality to piglets worldwide. Most vaccines used to combat the disease have been ineffective live attenuated virus vaccines. The goal of this project was to produce a plant-made subunit vaccine based off the membrane protein of the virus. This is the first time this protein has been produced in plants. An elastin-like polypeptide fusion membrane protein accumulated up to 0.8 mg/g of fresh leaf weight when transiently expressed in Nicotiana benthamiana. Virus-like particles were also produced for the first time for PEDv, and were able to form with just the membrane …

Insights Into The Role Of Connexin26 And Connexin30 In Skin Health, Syndromic Disease, And Cutaneous Wound Healing, Eric R. Press

Electronic Thesis and Dissertation Repository

Connexin26 (Cx26) and Cx30 facilitate gap junctional intercellular communication (GJIC) in the epidermis and are linked to several syndromic skin diseases. We investigated 5 disease- linked Cx26 mutants and demonstrated that the severity and extent of disease can be predicted from the gain- or loss-of function properties of each mutant, as well as the ability to induce cell death. We also used transgenic mice expressing S17F Cx26 (linked to keratitis-ichthyosis- deafness syndrome) or A88V Cx30 (linked to Clouston Syndrome) to investigate the pathophysiology these skin diseases. We demonstrated that S17F Cx26, but not A88V Cx30, promotes palmoplantar keratoderma by disrupting …

Comprehensive Molecular Characterization Of Human Nodal, Scott D. Findlay

Electronic Thesis and Dissertation Repository

Nodal and related ligands are highly conserved members of the TGF-beta superfamily with well-established and essential roles in the early embryonic development of vertebrates, and in cell fate decisions in human embryonic stem (hES) cells. Aberrant NODAL signaling also generally promotes pro-tumourigenic phenotypes and the progression of a wide array of human cancers. Despite being pursued as a potential therapeutic target, many aspects of NODAL’s molecular biology remain poorly understood. This thesis provides a comprehensive characterization of gene expression from the human NODAL locus at multiple levels. First, an intronic NODAL SNP known as rs2231947 was found to be functional …

Riboregulation Of Bacterial Transposons, Michael J. Ellis

Electronic Thesis and Dissertation Repository

Bacterial transposons typically exist in a mutually beneficial relationship with the host cell. Limited transposition can benefit the host while also ensuring the survival of the element. An important component of this relationship is that transposition must be tightly regulated. In this thesis I explore ways that the host and transposon each control transposition in E. coli and provide evidence that a transposon can also control host gene expression in S. enterica Typhimurium. Post-transcriptional regulation with small non-coding RNAs (sRNA) has emerged as a key way that bacteria respond to stress and regulate many cellular processes. The RNA-binding protein Hfq …

The Impacts Of Climate Change On Communities Of Fungi In Boreal Peatlands, Asma Asemaninejad Hassankiadeh

Electronic Thesis and Dissertation Repository

Peatlands have an important role in global climate change through sequestration of atmospheric CO₂. Climate change is already affecting these ecosystems, including both above- and below- ground communities and their functions. Fungi play a central role in these communities. As a result, there is concern that altered fungal community function may turn peatlands from carbon sinks to carbon sources, greatly exacerbating the impacts of climate change. In order to gain a better insight into effects of climate change on the structure and function of these carbon sequestrating ecosystems, this thesis focuses on diversity and structure of fungal communities …

Effects Of Gut-Associated Yeasts On Drosophila Melanogaster Performance, Yanira Jiménez Padilla

Electronic Thesis and Dissertation Repository

I used Drosophila melanogaster as a model to study the role of the gut microbiota, specifically yeasts, in animal physiology. I used Saccharomyces cerevisiae, the yeast commonly included in Drosophila diet, and Lachancea kluyveri, isolated from some Drosophila in the wild, and generated axenic (germ-free) and gnotobiotic (yeast-fed) flies. I found that L. kluyveri persists in the crop, as ascospores and vegetative cells, longer than S. cerevisiae. Some L. kluyveri vegetative cells survive passage through the gut. Egg to adult development time is reduced by 14% in vials containing live L. kluyveri or S. cerevisiae, whereas …

Characterization Of Ranbpm Subcellular Localization And Function In Hdac6 Regulation, Louisa M. Salemi

Electronic Thesis and Dissertation Repository

RanBPM has been shown to interact with numerous proteins implicating it in a variety of cellular processes including apoptosis, transcription regulation, cell migration, adhesion and morphology and has been shown to have tumour suppressive functions. RanPBM has been hypothesized to be a scaffolding protein and is part of a large protein complex termed the CTLH complex. Although the homologous complex in yeast has been demonstrated to have E3 ubiquitin ligase activity, whether the evolutionarily conserved human complex retains this activity remains to be determined. In this work we aim to characterize the regions of RanBPM that regulate its subcellular localization …

Impact Of Extremely Low-Frequency Magnetic Fields On Human Postural Control, Alicia N. Allen

Electronic Thesis and Dissertation Repository

The general public and workers can be exposed to high-levels of power-line frequency magnetic fields (MFs - up to 10 mT). Although such time-varying MFs have the potential to modulate human postural control, no existing studies have explored MF exposure levels that possibly trigger acute sway responses. This work evaluates time-varying MF exposure (up to 100 mT) in the extremely low frequency range (ELF – up to 300 Hz) and its effects on human postural control. Twenty-two healthy participants were each exposed to randomized, 5-second MF and electric stimulations (0, 50 and 100 mT and 1.5 mA respectively) given at …

Species Pluralism: Conceptual, Ontological, And Practical Dimensions, Justin Bzovy

Electronic Thesis and Dissertation Repository

Species are central to biology, but there is currently no agreement on what the adequate species concept should be, and many have adopted a pluralist stance: different species concepts will be required for different purposes. This thesis is a multidimensional analysis of species pluralism. First I explicate how pluralism differs monism and relativism. I then consider the history of species pluralism. I argue that we must re-frame the species problem, and that re-evaluating Aristotle's role in the histories of systematics can shed light on pluralism. Next I consider different forms of pluralism: evolutionary and extra-evolutionary species pluralism, which differ in …

Regulation Of E2f1 In Keratinocytes During Uv-Damage And Differentiation, Randeep K. Singh

Electronic Thesis and Dissertation Repository

The E2F1 transcription factor regulates the expression of key genes involved in cell proliferation and differentiation to maintain skin homeostasis. The expression of E2F1 is tightly regulated during cell cycle progression and when cells are committed to differentiate, as well as in response to DNA damage. In keratinocytes, E2F1 protein and transcript levels increase following UV-induced DNA damage, whereas, in response to Ca2+-induced differentiation, both E2F1 protein and transcript levels decrease. In this thesis, I examined in detail the mechanism that modulates E2F1 stability following DNA damage and during keratinocyte differentiation. I show that E2F1 associates with hHR23 and together …

The Use Of P3b As An Indicator Of Neurophysiologic Change From Subconcussive Impacts In Football Players, Jeffrey S. Brooks

Electronic Thesis and Dissertation Repository

There is a growing appreciation in research that subconcussive impacts may affect cognitive functioning. Canadian University football players (n=45) were separated into three groups based on their position/skill (small skilled, big skilled and big unskilled). An impact measuring device (GForceTracker) was used to record the number of impacts that each player experienced in a season. Player groups were separated into two levels of impact exposure: low and high. Players completed baseline, midseason, postseason, and follow-up neurophysiological tests (four months later) to measure P3b amplitude in response to a visual oddball paradigm, and high versus low impact subgroups for each player …

A Rat Model Of Cognitive Bias And The Effect Of Acute Corticosterone, Kai Wang

Electronic Thesis and Dissertation Repository

In humans, affective states can influence cognitive processes, resulting in a phenomenon referred to as “cognitive bias”. Rodents exhibit similar biases during the interpretation of ambiguous cues. It has been shown that cognitive bias shifts towards the negative valence (pessimism) when animals are under chronic stress manipulations. However, the effects of acute stress on cognitive bias have not been well established in an animal model. Here, a non-operant appetitive task using fluid rewards and distinct visual/tactile cues was developed to examine cognitive bias in male rats. Corticosterone was used to mimic stress levels similar to acute restraint stress. It was …

Corticotropin Releasing Factor Receptor Type 1 Signaling In Epilepsy And Traumatic Brain Injury, V V Chakravarthi Narla

Electronic Thesis and Dissertation Repository

Stress increases the frequency by which epileptic seizures occur. Corticotropin-releasing factor (CRF) coordinates neuroendocrine, autonomic and behavioral response to stress. This thesis sought to study the cellular and molecular mechanisms by which CRF regulates the activity of neural circuits in the piriform cortex (PC) in normal and epileptic states. The PC is richly innervated by CRF and 5-HT containing axons arising from the central amygdala and raphe nucleus. CRFR₁ and 5-HT_2A/CRs have been shown to interact in a manner where CRFR activation subsequently potentiates the activity of 5-HT_2A/CRs. The first purpose of this thesis was …

Molecular Characterization Of Viruses Infecting Greenhouse Vegetables In Ontario, Bin Chen

Electronic Thesis and Dissertation Repository

Greenhouse vegetable production is a very important and successful agricultural sector in Ontario. However, newly emerging viral or virus-like diseases have become a major limiting factor in greenhouse vegetable production. To determine the identity of the viral pathogens in the three major greenhouse vegetables in Ontario, we conducted in-depth sequencing of small RNAs isolated from virally infected plants used next-generation sequencing technology. Subsequent bioinformatics analyses revealed six viral pathogens including Bell pepper endornavirus (BPEV), Parietaria mottle virus (PMoV), Cucumber green mottle mosaic virus (CGMMV), Tobacco streak virus (TSV), Pepper mild mottle virus (PMMoV), and Pepino mosaic virus (PepMV). The full-length …

The Role Of Cholinergic Neurotransmission In Sensory Filtering And Sensorimotor Gating, Erin Azzopardi

Electronic Thesis and Dissertation Repository

At every moment, our brain is bombarded with sensory information. How we filter and process sensory information is critical for daily functioning and cognition. Examples of sensory filtering include habituation (a progressive decrease in responding) and prepulse inhibition (PPI, gating of responding). Our aim is to understand the differential role acetylcholine (ACh) plays in these processes.

To study this we used both reflexive (acoustic startle response: ASR) and non-reflexive (locomotor) behaviours. PPI is hypothesized to occur via inhibitory cholinergic projections from the Pedunculopontine Tegmental Nucleus (PPT) to the startle pathway. The role of ACh in habituation of reflexive and non-reflexive …

The Effects Of Ice Hockey Goaltender Leg Pads On Safety And Performance, Ryan J. Frayne

Electronic Thesis and Dissertation Repository

Ice hockey goaltenders have the highest percentage of cam-type femoroacetabular impingement (FAI). The exact cause of these injuries in goaltenders remains unknown; however, it has been suggested that common goaltender movements and a goaltender’s underlying hip pathology may be contributing factors. The butterfly save technique, commonly used by goaltenders, has been linked to FAI. Simply stopping these movements would likely be detrimental to goaltender performance. Therefore, changing other aspects of goaltending, such as altering the goaltender equipment, should be considered. The overall objective of this thesis was to understand how ice hockey goaltender leg pads influence both the safety and …

Cell Signaling Crosstalk And Differentiation Of F9 Cells Into Extraembryonic Endoderm, Gurjoth Singh Deol

Electronic Thesis and Dissertation Repository

Mouse F9 cells differentiate into primitive endoderm (PrE) when treated with retinoic acid (RA). During PrE differentiation the canonical Wnt signaling pathway is known to play an integral role in the process. In addition to Wnt signaling, there have been implications that the Hedgehog (Hh) pathway may also be involved. Previous results show that the Indian Hedgehog (Ihh) gene is upregulated during RA-induced differentiation; however further details of Hh signaling during PrE differentiation have yet to be discovered. A Gli-luciferase construct indicated that Hh signaling increases during RA-induced differentiation, implicating that the pathway is involved in PrE formation. Inhibiting …

Identification And Characterization Of The Isoflavonoid-Specific Prenyltransferase Gene Family To Prevent Stem And Root Rot In Soybean, Arjun Sukumaran

Electronic Thesis and Dissertation Repository

Soybean is one of the most predominantly grown legumes worldwide, however, one deterrent to maximizing its yield is the pathogen, Phytophthora sojae, which causes stem and root rot disease. Many strategies have been implemented to combat this pathogen such as use of pesticides and certain agricultural practices. However, these have been largely ineffective in completely preventing P. sojae infection. An alternative strategy would be to improve the innate resistance of soybean by promoting increased glyceollin production. Glyceollins are soybean-specific antimicrobial agents which are derived from the isoflavonoid branch of the general phenylpropanoid pathway. Soybeans produce 3 forms of glyceollin: …

Development And Performance Evaluation Of An Antibody-Based Technology For Detection Of E. Coli O157 In Meat Samples And Its Potential Evolution Using Antibody Engineering, Yadira Tejeda Saldaña

Electronic Thesis and Dissertation Repository

Escherichia coli O157 is a persistent pathogen linked to food and waterborne infectious outbreaks with severe health consequences such as hemorrhagic colitis and hemolyticuremic syndrome (HUS). Because it is considered one of the major pathogens that contributes to the global burden of foodborne disease, its early detection within the food chain is an important milestone towards reducing foodborne diseases and economic losses due to contaminated food. Herein, the development and validation of a lateral flow immunoassay (LFIA) point-of-care (POC) device is described. Application of the LFIA test kit was focused on detection of E. coli O157 in raw meat products …

Hemolytic Activity In The Euryhaline Fish-Killing Phytoflagellate Prymnesium Parvum Under Environmental Stresses, Christine Dulal-Whiteway

Electronic Thesis and Dissertation Repository

Harmful algal blooms (HABs) are vast expanses of noxious or toxic phytoplankton that periodically dominate coastal ocean waters or freshwater systems. An especially damaging type of HAB are the species that kill fish. In this thesis, a potentially invasive marine fish-killing flagellate, Prymnesium parvum, was investigated for its tolerance to freshwater conditions. This species has invaded some freshwater systems in the southern United States. The thesis examines if the growth rate and toxicity of Prymnesium parvum remain high under low salinities similar to freshwater systems. A hemolytic lysis assay was used as a proxy for toxicity. The findings presented …

Identification Of A Novel Interaction Between Integrin-Linked Kinase And Beta-Arrestin 1, Hannah E. Murphy-Marshman

Electronic Thesis and Dissertation Repository

Integrin-linked kinase (ILK) is a ubiquitous scaffold protein essential for the development of front-rear polarity and directional migration of epidermal keratinocytes. β-arrestin 1 is another adaptor protein which has recently emerged as a key factor in modulating proliferation and migration of various cell types. Previous studies have demonstrated an association between β-arrestin 2 and ILK in cerebellar granule precursor cells. I have now identified a novel interaction between ILK and β-arrestin 1 in primary keratinocytes that occurs directly and without post-translational modifications. The N-terminal 67 residues of ILK and multiple regions in β-arrestin 1 are important for this interaction. This …

The Neural Mechanisms Of Musical Rhythm Processing: Cross-Cultural Differences And The Stages Of Beat Perception, Daniel J. Cameron

Electronic Thesis and Dissertation Repository

Music is a universal human behaviour, is fundamentally temporal, and has unique temporal properties. This thesis presents research on the cognitive neuroscience of the temporal aspects of music: rhythm, beat, and metre. Specifically, this work investigates how cultural experience influences behavioural and neural measures of rhythm processing, and the different neural mechanisms (with particular interest in the role of the striatum) that underlie different stages of beat perception, as musical rhythms unfold.

Chapter 1 presents an overview of the existing literature on the perceptual, cognitive, and neural processing of rhythm, including the entrainment of neural oscillations to rhythm and the …

Evapotranspiration From Extensive Green Roofs: Influence Of Climatological Conditions, Vegetation Type, And Substrate Depth, Maria Eloisa Sia

Electronic Thesis and Dissertation Repository

Green roofs are gaining popularity worldwide as a low impact development tool to mitigate increasing stormwater runoff within dense urban areas. Evapotranspiration (ET) is the key hydrologic process governing the capacity of a green roof to retain rainfall as it regenerates available water storage space in the green roof substrate (soil) between rainfall events. To date, there are limited data on how the interaction between different climatological conditions and design parameters (e.g., vegetation type, substrate depth) affect ET rates. This currently limits the ability to optimize green roof design for stormwater management. In this field study, the impact of climatological …

Role Of Anterior Cingulate Cortex In Saccade Control, Sahand Babapoor-Farrokhran

Electronic Thesis and Dissertation Repository

Cognitive control is referred to the guidance of behavior based on internal goals rather than external stimuli. It has been postulated that prefrontal cortex is mainly involved in higher order cognitive functions. Specifically, anterior cingulate cortex (ACC), which is part of the prefrontal cortex, is suggested to be involved in performance monitoring and conflict monitoring that are considered to be cognitive control functions.

Saccades are the fast eye movements that align the fovea on the objects of interest in the environment. In this thesis, I have explored the role of ACC in control of saccadic eye movements. First, I performed …

Algorithms For Glycan Structure Identification With Tandem Mass Spectrometry, Weiping Sun

Electronic Thesis and Dissertation Repository

Glycosylation is a frequently observed post-translational modification (PTM) of proteins. It has been estimated over half of eukaryotic proteins in nature are glycoproteins. Glycoprotein analysis plays a vital role in drug preparation. Thus, characterization of glycans that are linked to proteins has become necessary in glycoproteomics. Mass spectrometry has become an effective analytical technique for glycoproteomics analysis because of its high throughput and sensitivity. The large amount of spectral data collected in a mass spectrometry experiment makes manual interpretation impossible and requires effective computational approaches for automated analysis. Different algorithmic solutions have been proposed to address the challenges in glycoproteomics …

A Test Of The Effects Of Androgens On Immunity: No Relationship Between 11-Keto Testosterone And Immune Performance In Bluegill Sunfish (Lepomis Macrochirus), John W. Loggie

Electronic Thesis and Dissertation Repository

The posited immunosuppressive effects of androgens are a key component of the immunocompetence handicap hypothesis (ICHH). My thesis uses bluegill sunfish (Lepomis macrochirus) to test two predictions arising from this hypothesis: (1) natural concentrations of the androgen 11-keto testosterone (11-KT) will be negatively related with immunity, and (2) an immunochallenge will lower 11-KT concentration. I found no evidence for a relationship between natural 11-KT concentration and measures of immunity (leukocyte counts, respiratory burst, cytokine gene expression), and an immunochallenge with Vibrio vaccine did not affect 11-KT concentration. I performed a meta-analysis of immunochallenge studies to help interpret my …