Life Sciences Commons^™

Expression Of Hepatic Cytochrome P450 Drug Metabolizing Enzymes In Diabetes And Diabetic Nephropathy, Cheng Jay Fang

Electronic Thesis and Dissertation Repository

The prevalence of diabetes worldwide is rapidly increasing. Polypharmacy, along with a high risk of adverse drug reactions, is common in diabetic patients. Cytochrome P450 (CYP) 3A and 2C drug metabolizing enzymes are reduced in chronic kidney disease (CKD), altering drug pharmacokinetics and contributing to adverse drug reactions. A large fraction of commonly prescribed drugs are metabolized by CYP3A and CYP2C. Approximately 40% of all CKD cases are attributed to diabetic nephropathy (DN) and early DN presents as mild kidney disease. This study aims to evaluate the impact of diabetes and DN on levels and activity of hepatic CYP3A and ...

Hitchhiker's Guide To Migration: Effects Of Experimental Parasitic Infection And Other Immune Challenges On Migratory Traits Of Sparrows, Tosha R. Kelly

Electronic Thesis and Dissertation Repository

Seasonal migration exposes animals to a variety of habitats and parasites, and if infected migratory birds migrate successfully there is great potential for birds to transport infectious diseases long distances. Our current understanding of whether birds contribute to the spread of disease relies upon observational field studies that are limited in their ability to discern cause from effect. Using captive and field-based experiments for my doctoral research, I answered three research questions: (1) are nocturnal migratory restlessness (Zugunruhe) and body condition affected by mounting an acute phase immune response during migration; (2) what are the impacts of parasitic infection on ...

The Effect Of Multiple Environmental Stressors On The Growth And Toxicity Of The Red Tide Alga Heterosigma Akashiwo, Malihe Mehdizadeh Allaf

Electronic Thesis and Dissertation Repository

Heterosigma akashiwo (Y.Hada) Y.Hada ex Y.Hara & M.Chihara is a golden-brown phytoflagellate with high potential to kill fish. These cells create large, nearly mono-specific blooms that persist from weeks to months. Although bloom persistence and frequency remain a mystery, environmental factors such as light, temperature, salinity and CO₂ level are proposed as drivers for both bloom initiation and toxicity. As timing and locations of nature blooms are difficult to predict, most of the information on this species comes from laboratory experiments on isolated cells. In this age, when multiple stressors occur simultaneously the traditional “One-factor-at-a-time” (OFAT ...

Predicting Response To Platin Chemotherapy Agents With Biochemically-Inspired Machine Learning, Peter Rogan, Eliseos J. Mucaki, Dan Lizotte

Biochemistry Publications

Selection of effective genes that accurately predict chemotherapy response could improve cancer outcomes. We compare optimized gene signatures for cisplatin, carboplatin, and oxaliplatin response in the same cell lines, and respectively validate each with cancer patient data. Supervised support vector machine learning was used to derive gene sets whose expression was related to cell line GI₅₀ values by backwards feature selection with cross-validation. Specific genes and functional pathways distinguishing sensitive from resistant cell lines are identified by contrasting signatures obtained at extreme vs. median GI₅₀ thresholds. Ensembles of gene signatures at different thresholds are combined to reduce dependence ...

Growth And Toxicity Of Geographically-Distinct Isolates Of The Fish-Killing Phytoflagellate, Heterosigma Akashiwo, Veerta Singh

Electronic Thesis and Dissertation Repository

Harmful Algal Blooms (HABs)—an accumulation of toxic phytoplankton—often result from environmental changes reflecting the increasing global human footprint and climate change. One HAB species drawing attention is Heterosigma akashiwo, a fish-killing flagellate that can cause extensive fish loss or be benign, depending on location or environmental conditions. Here, I investigate if this difference in toxicity is regulated by environmental conditions or differences in cellular physiology. Six strains were examined. Three originate from the Salish Sea, where fish-kills are common, and three from Japan, where blooms of Heterosigma are common but fish-kills are rare. By measuring growth and toxicity ...

Immunization With Recombinant Myelin Oligodendrocyte Glycoprotein Identifies Autoreactive T Cells As A Limiting Factor In Autoreactive Germinal Center Maintenance, Rajiv William Jain

Electronic Thesis and Dissertation Repository

Germinal center (GC) responses are responsible for the protection provided by immunizations but can also drive autoimmunity. B and T cells collaborate in the GC to target the same antigen (Ag) to inform B cell differentiation; however, the properties of Ags differ substantially in autoimmunity and foreign-Ag driven immunity. Currently, it is not well understood how properties of the Ag itself influence the initiation or progression of GC responses, limiting our ability to develop effective vaccinations and predict the progression of autoimmune responses. The purpose of this thesis is to assess how GC responses initiate and progress when immunizing with ...

Cardiodynamic Associations With Resilience In Undergraduate Students And The Effect Of A Mentorship Intervention, Rachel J. Knetsch

Electronic Thesis and Dissertation Repository

The National College Health Assessment (NCHA) indicates that a majority of Canadian university students report feeling overwhelmed, stressed, and anxious during their undergraduate studies. Resilience refers to positive adaptation, or the ability to maintain or regain mental health, despite experiencing adversity (Herrman et al., 2011). While autonomic indices have been used to describe chronic physiological stress, the role of heart rate variability (HRV) as an index of resilience remains unclear. This research tested the hypotheses that (1) there is a relationship between HRV and resilience scoresand (2) a mentorship intervention will improve HRV and resilience outcomes. Fifty-seven first year students ...

A Comprehensive Catalog Of Post-Translational Modifications Of Drosophila Melanogaster Hox Protein, Sex Combs Reduced, Anirban Banerjee

Electronic Thesis and Dissertation Repository

During formation of the anterior-posterior axis, Homeotic selector (HOX) proteins determine the identity of Drosophila body segments. HOX proteins are transcription factors that regulate gene expression during development. Besides a highly conserved DNA-binding homeodomain (HD), HOX proteins also contain functionally important, evolutionarily conserved small motifs. These short motifs found in HOX proteins may be Short Linear Motifs (SLiMs). SLiMs are proposed to be sites of phosphorylation and this may regulate the activity of HOX proteins. The primary aim of this work was to develop a comprehensive catalogue of the sites of phosphorylation and other post-translational modifications (PTMs) for Fushi tarazu ...

The Effects Of Perceived Predation Threat On Stress Response And Memory In Birds, Chlöe S. N. Carter

Electronic Thesis and Dissertation Repository

This study examined how perception of predator cues, across three sensory modalities, affects physiology and behaviour of songbirds. I hypothesized that the perception of predator threat would elicit physiological and behavioural responses in both acute and chronic exposure conditions. My first study examined the responses of wild-caught black-capped chickadees (Poecile atricapillus) and house sparrows (Passer domesticus), as well as lab-bred zebra finches (Taeniopygia guttata), to acute predation cue exposure by coding video recorded behaviour and corticosterone analysis. My second study examined changes in black-capped chickadees’ foraging behaviour and memory retention after chronic exposure to acoustic predation cues. There were no ...

Effects Of Maternal Protein Restriction On The Pulmonary Surfactant System During The Early Life And Adulthood, Reza Khazaee

Electronic Thesis and Dissertation Repository

Fetal growth restriction (FGR) is defined by low birth weight and contributes to a variety of adult-onset diseases with different severities between males and females. However, the effects of FGR on the pulmonary surfactant are not fully elucidated. In this thesis, first, we investigated the FGR effects on the lung function and the surfactant system at the early postnatal life. It was hypothesized that FGR contributes to alterations of lung mechanics and the surfactant system during the neonatal period. Second, we assessed the FGR effects on the surfactant system in response to sepsis in adulthood. It was hypothesized that FGR ...

Adaptation Mechanisms Of Two-Spotted Spider Mite, Tetranychus Urticae, To Arabidopsis Indole Glucosinolates, Golnaz Salehipourshirazi

Electronic Thesis and Dissertation Repository

The two-spotted spider mite Tetranychus urticae Koch is a key agricultural pest that causes significant yield losses in a wide range of economically important crops. Rapid development of resistance to several classes of pesticides in T. urticae necessitates introduction of alternative management strategies to control this pest. Indole glucosinolates (IGs) are secondary metabolites found in Brassicaceae plants (including Arabidopsis thaliana) that have been shown to be effective against T. urticae and could be potential candidates to control spider mites. However, a laboratory population selected on IG-containing Arabidopsis was able to evolve adaptation to this plant. The overall objective of this ...

Cannabinoid Transmission In The Basolateral Amygdala Modulates Prefrontal Cortex And Ventral Hippocampal Activity, Brian J. Pereira

Electronic Thesis and Dissertation Repository

The cannabinoid system is important for maintaining neuron-to-neuron communication within the mammalian brain. One of the most commonly used substances to alter the cannabinoid system is cannabis. Individuals who are exposed to cannabis report having dissociable effects; both positive and negative. High amounts of THC have been commonly associated with the negative effects of cannabis, whereas CBD can be used to counter these. Pre-clinical evidence suggests that the combination of the two compounds can produce a therapeutic benefit for individuals who are susceptible to the effects of THC. The present study investigates whether the combination of THC+CBD can prevent ...

Dna Sequence Classification: It’S Easier Than You Think: An Open-Source K-Mer Based Machine Learning Tool For Fast And Accurate Classification Of A Variety Of Genomic Datasets, Stephen Solis-Reyes

Electronic Thesis and Dissertation Repository

Supervised classification of genomic sequences is a challenging, well-studied problem with a variety of important applications. We propose an open-source, supervised, alignment-free, highly general method for sequence classification that operates on k-mer proportions of DNA sequences. This method was implemented in a fully standalone general-purpose software package called Kameris, publicly available under a permissive open-source license. Compared to competing software, ours provides key advantages in terms of data security and privacy, transparency, and reproducibility. We perform a detailed study of its accuracy and performance on a wide variety of classification tasks, including virus subtyping, taxonomic classification, and human haplogroup assignment ...

The Post-Fledging Survival And Movements Of Juvenile Barn Swallows (Hirundo Rustica): An Automated Telemetry Approach, Dean R. Evans

Electronic Thesis and Dissertation Repository

For migratory songbirds, population dynamics are primarily influenced by juvenile or first year survival, but survival between fledging and fall migration is particularly important. Unfortunately, our knowledge of this post-fledging period is largely limited due to the difficulty of tracking juveniles outside the nest. For this thesis, I used automated radio telemetry to track the survival and post-fledging movements of 216 juvenile Barn Swallows (Hirundo rustica) from fledging up until departure for autumn migration in 2016-2017. Average apparent survival was 42% for both broods and nestlings in better body condition had higher survival. Nestlings from second broods migrated 21 days ...

Hierarchical Variation In Cellulose Decomposition Across Southern Ontario Reference Streams, Jenna R. Webb

Electronic Thesis and Dissertation Repository

The cotton strip assay (CSA) has been promoted as a method of incorporating functional indicators into standardized river assessments by study of organic-matter decomposition. However, operationalization of the CSA as an indicator requires testing the spatial and temporal controls of variance associated with decomposition of cotton strips at regional reference sites. I conducted a hierarchically structured study of decomposition rates in Ontario, Canada. Cotton strips were deployed during the spring, summer and fall in pool and riffle habitats of 22 streams located in three distinct physiographic regions. Partitioning of variation among hierarchical scales associated with rates of decomposition were examined ...

Overwintering Biology Of The Brown Marmorated Stink Bug, Halyomorpha Halys (Hemiptera: Pentatomidae), John Ciancio

Electronic Thesis and Dissertation Repository

The invasive crop pest Halyomorpha halys has been established in Ontario since 2012 and poses a significant threat to Canadian agriculture. I investigated the tolerance of H. halys to three stressors - low temperatures, desiccation, and energy depletion - in addition to investigating the role of lab-induced diapause in enhancing stress tolerance. Overwintering H. halys depress their supercooling point to -15.4 °C and LT₅₀ to -17.5 °C after acute (1 h) exposure, however they do not encounter these temperatures while overwintering indoors. Moreover, overwintering H. halys maintain their water balance through a reduction of water loss rates, while conserving ...

Measuring The Impact Of A Weeklong Fall Break On Stress Physiology In First Year Engineering Students, Ayesha Khan, Heather Poole, Elliott A. Beaton

The Canadian Journal for the Scholarship of Teaching and Learning

Canadian post-secondary institutions are increasingly introducing a fall break into their term calendars, with the stated goal of reducing student stress and improving academic success. We conducted a pilot study around the time of this fall break during which we collected saliva samples to measure the ratio of two metabolic hormones (cortisol and dehydroepiandrosterone (DHEA)) from first-year male engineering students in order to document possible changes in their stress levels before and after the break. Participants self-identified a particular day in the week prior to the break that they considered to be most stressful, followed by a day in the ...

Endothelial Glycocalyx Shedding In Pediatric Diabetic Ketoacidosis, Rufina Ning

Electronic Thesis and Dissertation Repository

Diabetic ketoacidosis (DKA) is a state of severe insulin deficiency resulting in hyperglycemia, ketoacidosis, and inflammation. Children with DKA have an increased risk of microvascular complications (e.g. stroke). The glycocalyx maintains the anti-thrombotic properties of endothelial cells (ECs), however the glycocalyx status is unknown in DKA. We quantified major glycocalyx components: hyaluronic acid (HA), heparan sulfate (HS), chondroitin sulfate (CS), and syndecan-1 in DKA plasma and correlated them with DKA severity. HA/HS were significantly increased in the plasma of DKA patients in comparison to insulin-controlled type-1 diabetics, but only HA correlated to DKA severity. Exogenous addition or removal ...

Characterizing The Cortical Contributions To Working Memory-Guided Obstacle Locomotion, Carmen Wong

Electronic Thesis and Dissertation Repository

While walking in complex environments, the ability to acquire information about objects in our surroundings is essential for successful obstacle negotiation. Furthermore, the ease with which most animals can traverse cluttered terrain while grazing, exploring, or hunting is facilitated by the capacity to store obstacle information in working memory (WM). However, the underlying neural substrates supporting such complex behaviours are poorly understood. Therefore, the goal of this thesis is to examine the neural underpinnings of WM-guided obstacle negotiation in the walking cat.

Obstacle locomotion was studied in two main paradigms, characterized by whether obstacle presence was detected via vision or ...

Effects Of Water Temperature, Rearing Temperature And Population On Swimming Performance And Temperature Preference In Atlantic Salmon (Salmo Salar), Nicole Zathey

Electronic Thesis and Dissertation Repository

Understanding how animals respond to environmental temperatures is important for the survival and reintroduction of species. My objectives were to determine how swim performance responds across water temperatures, and how rearing temperature or population would affect this performance and temperature preference. Juvenile Atlantic salmon (Salmo salar) from two populations that are currently used for stocking in Lake Ontario (LaHave, Sebago) were reared at two temperatures (11°C, 19°C). I measured critical swim speed and burst swim speed across eight water temperatures (11 – 25°C). Water temperature had no effect on burst speed, while critical swim speed increased with increased ...

Operant Conditioning Of Human Upper-Limb Stretch Reflexes, Ehsan Abolhasani

Electronic Thesis and Dissertation Repository

Operant conditioning of short-latency reflex (SLR) and H-reflex have been investigated in animals and humans. We modified previously established protocols for conditioning lower limb H-reflexes to up-condition the SLR in brachioradialis muscle and to investigate the effect of such conditioning on the long-latency response (LLR) of synergistic muscles. Our study included 12 healthy participants. Each participant took part in 3 baseline and 27 conditioning sessions in 6 weeks, followed by two additional sessions one month and two months after the last conditioning session. We found an increase in SLR magnitude in 50% of participants (by 15%±2.50). However, there ...

Developing A Sustainable Insect Pest Management System By Manipulating Plant Volatile Emissions, Scott R. Hughes

Electronic Thesis and Dissertation Repository

Herbivorous insects are a constant problem for farmers and growers globally, who rely on insecticides to control pest populations. Alternative measures are required due to insects developing resistance to chemical insecticides, along with increasing pressure from consumers. Integrated pest management (IPM) programs are a popular alternative. IPM uses a multifaceted approach to reduce pest populations below economic injury thresholds. Many plant-insect interactions are modulated by plant volatile organic compound (VOC) emissions. Manipulating this communication channel by producing transgenic plants with modified VOC emissions could provide another tool for use in IPM programs. I developed tomato Solanum lycopersicum (L.) plants expressing ...

The Effect Of Shelter Availability On Foraging In Atlantic Salmon (Salmo Salar), Christian A. Therrien

Electronic Thesis and Dissertation Repository

Shelter is an environmental feature that provides protection from danger and its use is an important anti-predator behavior for juvenile Atlantic salmon (Salmo salar). However, how shelter availability influences the foraging of these fish in the wild is not well documented. I predicted that juvenile Atlantic salmon would alter their foraging behavior in a low shelter environment and that this effect would differ between individuals from two populations that are targeted for reintroduction into Lake Ontario. I measured the foraging activity of juvenile Atlantic salmon from the two populations while they were held in pens in a Lake Ontario tributary ...

Mechanisms Underlying Freeze Tolerance In The Spring Field Cricket, Gryllus Veletis, Jantina Toxopeus

Electronic Thesis and Dissertation Repository

Freeze tolerance has evolved repeatedly across insects, facilitating survival in low temperature environments. Internal ice formation poses several challenges, but the mechanisms that mitigate these challenges in freeze-tolerant insects are not well understood. To better understand how insects survive freezing, I describe a novel laboratory model, the spring field cricket Gryllus veletis (Orthoptera: Gryllidae). Following acclimation to six weeks of decreasing temperature and photoperiod (mimicking autumn), G. veletis juveniles becomes moderately freeze-tolerant, surviving freezing at -8 °C for up to one week, and surviving temperatures as low as -12 °C. Acclimation is associated with increased control of the temperature and ...

Phylogeny, Heat-Stress And Enzymatic Heat-Sensitivity In The Antarctic Psychrophile, Chlamydomonas Sp. Uwo 241, Marc Possmayer

Electronic Thesis and Dissertation Repository

Psychrophilic species, micro-organisms which are unable to grow at temperatures of or above 20°C, are abundant in perennially cold ecosystems across the globe. Intensifying scientific investigation of these organisms from ecological to molecular scales has underscored the ability of life on Earth to adapt to environments which seem inhospitable due to high or low temperatures, high salinity, pressure and light, and ultra-low nutrient availability. Psychrophilic organisms that are also photosynthetic represent a much more limited group than psychrophiles generally, as their habitats must be well buffered against the warming influence of the infra-red energy accompanying sunlight. Photosynthetic psychrophiles face ...

Comparative Study Of Beat And Temporal Pattern Perception In A Songbird, Brendon Samuels

Electronic Thesis and Dissertation Repository

When humans listen to musical rhythms they sense a beat, the regular pulse that one might tap their foot to. Much about the functions, evolution and neural substrates of beat perception remains unclear. Research has considered whether other species perceive beat, yet more empirical data is needed. Songbirds produce learned rhythmic vocalizations, but can they perceive a beat? To answer this question, I developed a behavioural task that tested whether humans could discriminate rhythms that contained or lacked a beat. I applied an equivalent procedure to test European starlings. I found that humans learned the task with minimal instructions, but ...

Performance Impact Of Different Lower-Limb Setup Positions In The Backstroke Swimming Start, Gordon E. Barkwell

Electronic Thesis and Dissertation Repository

The performance impact of different knee extension angles in the setup position for a backstroke start was evaluated using an instrumented starting surface. Ten backstroke swimmers completed maximum-effort starts in each of two setup positions: one with the knees flexed, and one with the knees extended. The start handles and touchpad were instrumented with tri-axial force plates. Activity of major hip and knee extensors was measured using surface electromyography. Body position was recorded throughout the start using two high-speed cameras. There was no difference in time to 10 m between the two conditions, indicating there is likely no advantage in ...

Motor Variability In Rowing, Maude Potvin-Gilbert

Electronic Thesis and Dissertation Repository

The aim of the study was to analyze the impact of environment, intensity and distance rowed on temporal variability of strokes and on knee angle variability. 11 participants rowed 2,000 m at high and low intensities on an ergometer and at high intensity in a single on-water. Data were collected at the beginning and at the end of each exercise. All the factors influenced significantly the temporal variability (respectively beta=-0.013 and p .007=; beta= 0.007 and p=.021; beta=0.06 and p=.028). The difference of visual information and the need of the rower to ...

Characterizing The Cognitive And Emotional Effects Of Delta-9-Tetrahydrocannabinol In Distinct Hippocampal Sub-Regions, Dinat Khan

Electronic Thesis and Dissertation Repository

The objective of this study is to determine the potential differential effects of THC in the DH or VH sub-regions, as well as the upstream effects on PFC neuronal activity and oscillations. Rodents used for electrophysiology were infused with THC or vehicle in the DH or VH regions, combined with PFC recordings. Additionally, a battery of behavioural paradigms was performed. Deficits in short-term memory when THC was infused into both regions was observed, however working memory was impaired with VH infusions only. This could be due to THC-induced dysregulation in the PFC, as beta oscillations were significantly decreased selectively in ...

Elucidation Of The Signaling Pathway Of Mertk, Kyle Taruc

Electronic Thesis and Dissertation Repository

Mer tyrosine kinase (MERTK) is a receptor tyrosine kinase which mediates efferocytosis-the recognition and uptake of apoptotic cells. MERTK serves as the predominant efferocytic receptor in several tissues, including in the heart, with single nucleotide polymorphisms associated with up to a 75% increased risk of atherosclerosis in humans. MERTK facilitates the internalization of apoptotic cells via a MERTK/integrin pathway that involves, in part, PI-3-kinase signaling and signaling via Src-family kinases. While these elements of the MERTK signaling pathway have been identified, much of MERTK’s signaling mechanisms remain to be elucidated. Pharmacological inhibitors were used to block signaling through ...