Life Sciences Commons^™

The Prevalence Of Ontario Undergraduate University Students Meeting The 24-Hour Movement Guidelines And The Role Of Perceived Social Support, Nia Contini

Electronic Thesis and Dissertation Repository

The extensive physical and mental health implications of physical activity, sedentary behaviour, and sleep are irrefutable. The COVID-19 pandemic has had drastic consequences on university students and their already poor movement behaviours. Recommendations for a healthful distribution of physical activity, sedentary behaviour, and sleep were presented in the Canadian 24-Hour Movement Guidelines for Adults. The current research sought to report the prevalence of Ontario undergraduate university students meeting the Guidelines approximately two and a half years into the pandemic and assess the association between meeting the Guidelines and perceived social support. A total of 508 undergraduate students registered at 19 …

Mining Sars-Cov-2 Phylogenetic Trees To Estimate Circulating Infections And Patterns Of Migration, Erin V. Brintnell

Electronic Thesis and Dissertation Repository

The SARS-CoV-2 pandemic led to the formation of very large databases of genomic viral data. These databases contain information on transmission dynamics, emergence and evolution of SARS-CoV-2. However, extracting this information from sequences is difficult, as most methods of analyzing viral genomes were developed for smaller data sets. Therefore, my objective was to develop new fast estimators of the number of infections (I) and the rate of migration based on simple features of SARS-CoV-2 phylogenies.

I simulated pathogen evolution using a susceptible-exposed-infectious-recovered (SEIR) model of pathogen spread, reconstructing evolution using CoVizu. For simulations of I, I varied the total number …

Elucidating The Neural Circuitry Underlying Social Spacing In Drosophila Melanogaster Through The Lens Of Neuroligin 3, Abigail T. Bechard

Electronic Thesis and Dissertation Repository

Social interactions among animals can be complex, and abnormal social behaviours may result in negative fitness consequences for both the individual displaying them, and the entire group. To understand the neural basis of complex social behaviour, we can study simpler behaviours that precede and mediate them. Social spacing, the typical distance between individuals in a group, is an easily quantifiable behaviour in Drosophila melanogaster. Here, I investigated the neural circuitry underlying social spacing through the lens of Autism-candidate gene neuroligin 3. Based on the Nlg3 enrichment pattern in adult fly brains, I hypothesized that nlg3-expressing neurons, along …

Msspl9 Modulates Nodulation Under Nitrate Sufficiency Condition In Medicago Sativa, Vida Nasrollahi, Gamalat Allam, Susanne E. Kohalmi, Abdelali Hannoufa

Biology Publications

Nodulation in Leguminous spp. is induced by common environmental cues, such as low nitrogen availability conditions, in the presence of the specific Rhizobium spp. in the rhizosphere. Medicago sativa (alfalfa) is an important nitrogen-fixing forage crop that is widely cultivated around the world and relied upon as a staple source of forage in livestock feed. Although alfalfa’s relationship with these bacteria is one of the most efficient between rhizobia and legume plants, breeding for nitrogen-related traits in this crop has received little attention. In this report, we investigate the role of Squamosa-Promoter Binding Protein-Like 9 (SPL9), a target of miR156, …

Development Of Reverse Genetics Tools In The Two-Spotted Spider Mite Tetranychus Urticae, Nivitha Bhaskar

Electronic Thesis and Dissertation Repository

Tetranychus urticae, commonly known as the two-spotted spider mite, poses a significant threat to agriculture due to its ability to feed on a diverse range of plant hosts and its strong detoxification abilities in overcoming xenobiotic response. With global warming projected to increase spider mite infestations, it is vital to study the detoxification genes that enable the mite to adapt and survive. The spider mite genome sequence reveals a unique set of detoxification genes that can be studied using RNAi as a promising reverse genetic tool. However, the current genetic toolkit requires improvement. This study examined the effectiveness of …

Post-Breeding Survival Of Adult And Hatch-Year Bank Swallows (Riparia Riparia) In The Great Lakes Region: A Radio Telemetry Study, Christian M.M Buchanan-Fraser

Electronic Thesis and Dissertation Repository

The post-breeding period poses significant threats to newly fledged birds due to predation, starvation, exposure to inclement weather, and collision risk prior to their first southward migration. I used automated radio telemetry to track 100 adult and 100 hatch-year Bank Swallows (Riparia riparia) in the Great Lakes ecoregion during the 2021 post-breeding period. Additionally, 74 hatch-year birds tracked in 2018 by Mitchell et al. were included. In 2021, daily apparent survival probability was higher for adults compared to hatch-years; we estimated that ~10% of hatch-year birds die within two weeks post-fledging but high rates of tag loss in …

The Neural Control Of Force Production In Response To Directional Force Challenges, Joshua W. Cohen

Electronic Thesis and Dissertation Repository

Maintenance of upright standing posture is fundamental to human mobility and requires muscular control of the body’s centre of mass over the base of support. Force production, necessary for standing, is achieved by neural activation of populations of motor units (MUs). The possibility of preferentially activating different MUs within or across synergists has been debated in the motor control literature. Accordingly, the overall objective of this dissertation was to examine the neural control of standing balance in response to different directional force challenges. High Density Surface-Electromyography (HD-sEMG) was used to observe the location of muscle activity, and signal decomposition techniques …

Combining Exercise With Cognitive Training And Vitamin D, Nick W Bray, Frederico Pieruccini-Faria, Suzanne T Witt, Robert Bartha, Timothy J Doherty, Lindsay S Nagamatsu, Quincy J Almeida, Teresa Liu-Ambrose, Laura E Middleton, Louis Bherer, Manuel Montero-Odasso

Kinesiology Publications

Changes in functional brain connectivity (FBC) may indicate how lifestyle modifications can prevent the progression to dementia; FBC identifies areas that are spatially separate but temporally synchronized in their activation and is altered in those with mild cognitive impairment (MCI), a prodromal state between healthy cognitive aging and dementia. Participants with MCI were randomly assigned to one of five study arms. Three times per week for 20-weeks, participants performed 30-min of (control) cognitive training, followed by 60-min of (control) physical exercise. Additionally, a vitamin D

A Review Of The Neural Basis Underlying The Acoustic Startle Response With A Focus On Recent Developments In Mammals, Alice Zheng, Susanne Schmid

Anatomy and Cell Biology Publications

The startle response consists of whole-body muscle contractions, eye-blink, accelerated heart rate, and freezing in response to a strong, sudden stimulus. It is evolutionarily preserved and can be observed in any animal that can perceive sensory signals, indicating the important protective function of startle. Startle response measurements and its alterations have become a valuable tool for exploring sensorimotor processes and sensory gating, especially in the context of pathologies of psychiatric disorders. The last reviews on the neural substrates underlying acoustic startle were published around 20 years ago. Advancements in methods and techniques have since allowed new insights into acoustic startle …

Mouse Genotyping Array-Based Analysis Of Variation At Single Nucleotide Polymorphic Loci In The Context Of Macro- And Micro-Environments, Freda Qi

Electronic Thesis and Dissertation Repository

Comparing genetic variation between populations can provide insight into selective pressures in the environment. The Mouse Diversity Genotyping Array (MDGA) is a low-cost, high-throughput tool developed to capture and analyze variation at single nucleotide polymorphic (SNP) loci in inbred mouse strains. However, its ability to assess genetic variation in non-inbred mice and associate SNPs with the environment has not been extensively studied. First, SNPs between laboratory inbred and wild-caught mice were compared. No SNPs were associated with either macroenvironment. Instead, SNPs reflected genealogy and inbreeding strategies, consistent with the MDGA’s intended use. Second, mutations at SNP loci were compared between …

Evaluating The Role Of Gras And Fadxdeba In Promoting Staphylococcus Aureus Adaptation To Host-Derived Fatty Acids Encountered At Sites Of Colonization And Infection, Robert C. Kuiack

Electronic Thesis and Dissertation Repository

Staphylococcus aureus is an opportunistic pathogen that asymptomatically colonizes 30% of humans, where it is well adapted to survive on the skin in the presence of innate defense mechanisms such as antimicrobial free fatty acids (FFA). While antimicrobial FFA function to inhibit the growth of S. aureus, they also provide a valuable source of lipids for membrane synthesis and energy production. We hypothesized that S. aureus possesses a novel antimicrobial FFA resistance pathway that is activated under conditions found on human skin, and that under these conditions, S. aureus can metabolize exogenous fatty acids to fuel growth and virulence …

Age And Sex Differences In Stopover Behaviours And Flight Performance In Black-Throated Blue Warblers, Patricia Rokitnicki

Electronic Thesis and Dissertation Repository

Differential migration by sex and age is commonly observed in passerines. Previous studies have found differences in wing morphology between sex and age classes which could affect their movement ecology. In this thesis, I examine whether migratory stopover duration and nocturnal flight speeds differed between age and sex classes in 89 Black-throated Blue Warblers (Setophaga caerulescens) using movement data obtained by Motus Wildlife Tracking System and meteorological data from the NCEP/NCAR Reanalysis II project. Second year birds (hatched during the previous breeding season) had longer stopovers but similar post-departure movements to after second year birds (hatched before the last breeding …

A Highly Charged Topic: Intrinsically Disordered Proteins And Protein Pka Values, Carter J. Wilson

Electronic Thesis and Dissertation Repository

Intrinsically disordered proteins (IDPs) are known not only for their roles in disease but also for their conformational flexibility, which makes them elusive for experimentation. We consider the role played by theory and simulation in resolving important questions pertaining to IDP structure and dynamics, as well as the nature of the charged residues (e.g., glutamate, lysine, etc.) that enrich them. Specifically, we investigated how the deep learning trained AlphaFold2 (AF2) predictor estimates disorder content, revealing both strong performance in relation to conventional approaches and an important relationship between the AF2 confidence metric and IDP dynamics. We also assessed how modern …

Genetic Tools Towards A Synthetic Biology Approach For Whole Mitochondrial Genome Engineering, Ryan R. Cochrane

Electronic Thesis and Dissertation Repository

Synthetic biology is an interdisciplinary research field that standardizes and repurposes biological components to better understand life and solve complex problems. As synthetic biology has developed, the goal has become to generate fully controllable biological systems through whole genome engineering (WGE), the cumulation of standardized genome engineering, and DNA delivery methods. In eukaryotes, genetic tools for WGE are limited to the nucleus and present a need to expand to include mitochondria, which maintains its own unique genome. The work presented here begins developing the resources needed to enable whole mitochondrial genome engineering.

First, to standardize mitochondrial genome engineering protocols, I …

Maturation Of Default Mode Network Functional Connectivity Strength In Utero And The Association With Subcortical Macrostructure: Mapping Brain Ontogeny Supporting Early Cognitive Processing, Susana Correa

Electronic Thesis and Dissertation Repository

The third trimester of gestation is scarcely studied despite this being a key window for the development of learning and memory systems. In a prospective cohort study, 30 pregnant women participated in one or two fetal MR imaging sessions between 28- and 39 weeks of gestational age. Activation time courses were extracted from the default mode (DMN), medial temporal lobe (MTL), and thalamocortical (TCN) networks of the fetal brain. Generalized estimating equations were used to examine the association between the DMN-MTL, DMN-TCV connectivity strength, and subcortical volumes. Increased functional connectivity strength between the DMN-MTL networks was negatively associated with smaller …

Development Of A High-Throughput Approach For Testing Optimal Fecal Microbiota Transplant Material, Shaeley Jae Gibbons

Electronic Thesis and Dissertation Repository

Historically used to treat Clostridioides difficile infection, fecal microbiota transplants (FMT) are now being tested to treat gut and systemic diseases, including (but not limited to) autoimmune, liver, and cardiovascular. Successful FMT relies on components within the donor sample, which may have specific conserved properties that vary greatly between individuals. Screening donors for potentially transmittable conditions is a well-established practice, however, screening material for the likeliness of a successful clinical outcome or finding the best match of material for patients has not been undertaken. We hypothesized an optimal donor may be selected by high-throughput in vitro screening of fecal microbiota. …

Plantar Flexor Dynamic Contractile Rates Are Not Dependent On Calcaneal Tendon Stiffness, Sohum Kulkarni

Electronic Thesis and Dissertation Repository

The ability to rapidly generate muscular torque and velocity is important in specialized activities and daily tasks of living. Tendon stiffness is one factor in the neuromuscular system that influences musculoskeletal torque transmission. Previous studies have reported weak-to-moderate correlations between tendon stiffness and rate of torque development (RTD). However, these correlations have been reported only for isometric contractions which may not be relevant to contractions involving joint rotation (i.e., dynamic). The purpose was to investigate the effect of calcaneal tendon stiffness on the dynamic rates of torque (RTD) and velocity (RVD) development in plantar flexor muscles. Young adult males (n=13) …

Spatiotemporally Dynamic Electric Fields For Brain Cancer Treatment: An In Vitro Investigation, Erin Iredale, Abdulla Elsaleh, Hu Xu, Paul Christiaans, Andrew Deweyert, John Ronald, Susanne Schmid, Matthew O Hebb, Terry M Peters, Eugene Wong

Anatomy and Cell Biology Publications

Objective. The treatment of glioblastoma (GBM) using low intensity electric fields (∼1 V cm^-1) is being investigated using multiple implanted bioelectrodes, which was termed intratumoral modulation therapy (IMT). Previous IMT studies theoretically optimized treatment parameters to maximize coverage with rotating fields, which required experimental investigation. In this study, we employed computer simulations to generate spatiotemporally dynamic electric fields, designed and purpose-built an IMT device for in vitro experiments, and evaluated the human GBM cellular responses to these fields. Approach. After measuring the electrical conductivity of the in vitro culturing medium, we designed experiments to evaluate the …

Developmental Changes In Electrophysiological Properties Of Auditory Cortical Neurons In The Cntnap2 Knockout Rat, Rajkamalpreet S Mann, Brian L Allman, Susanne Schmid

Anatomy and Cell Biology Publications

Disruptions in the CNTNAP2 gene are known to cause language impairments and symptoms associated with autism spectrum disorder (ASD). Importantly, knocking out this gene in rodents results in ASD-like symptoms that include auditory processing deficits. This study used in vitro patch-clamp electrophysiology to examine developmental alterations in auditory cortex pyramidal neurons of Cntnap2^-/- rats, hypothesizing that CNTNAP2 is essential for maintaining intrinsic neuronal properties and synaptic wiring in the developing auditory cortex. Whole cell patch-clamp recordings were conducted in wildtype and Cntnap2^-/- littermates at three postnatal age ranges (P8-12, P18-21, and …

Novel 129xe Magnetic Resonance Imaging And Spectroscopy Measurements Of Pulmonary Gas-Exchange, Alexander M. Matheson

Electronic Thesis and Dissertation Repository

Gas-exchange is the primary function of the lungs and involves removing carbon dioxide from the body and exchanging it within the alveoli for inhaled oxygen. Several different pulmonary, cardiac and cardiovascular abnormalities have negative effects on pulmonary gas-exchange. Unfortunately, clinical tests do not always pinpoint the problem; sensitive and specific measurements are needed to probe the individual components participating in gas-exchange for a better understanding of pathophysiology, disease progression and response to therapy.

In vivo Xenon-129 gas-exchange magnetic resonance imaging (¹²⁹Xe gas-exchange MRI) has the potential to overcome these challenges. When participants inhale hyperpolarized ¹²⁹Xe gas, it …

De Novo Sequencing Of Multiple Tandem Mass Spectra Of Peptide Containing Silac Labeling, Fang Han

Electronic Thesis and Dissertation Repository

The systematic studies of proteins has gradually become fundamental in the research related to molecular biology. Shotgun proteomics use bottom-up proteomics techniques in identifying proteins contained in complex mixtures using a combination of high performance liquid chromatography coupled with mass spectrometry technology. Current mass spectrometers equipped with high sensitivity and accuracy can produce thousands of tandem mass spectrometry (MS/MS) spectra in a single run. The large amount of data collected in a single LC-MS/MS run requires effective computational approaches to automate the process of spectra interpretation. De novo peptide sequencing from tandem mass spectrometry (MS/MS) has emerged as an important …

Molecular Characterization Of The Antiviral Properties Of The Small Herc Family Of Proteins, Ermela Paparisto

Electronic Thesis and Dissertation Repository

Although viruses are obligate intracellular parasites, they have their own evolutionary trajectory, their genomes are in a constant battle to overcome the defenses of the host. This thesis investigates the role of the small HERC family of proteins in the battle against two deadly viruses: Human Immunodeficiency Virus -1 (HIV) and Zaire ebolavirus (EBOV). Although their discovery occurred decades ago, little knowledge is available about the small HERC family, their functions, and modes of interactions with other cellular proteins. In the first chapter, the structural evolution of the small HERC family and related functional changes that have occurred over time …

Multi-View Contrastive Learning For Unsupervised Domain Adaptation In Brain-Computer Interfaces, Sepehr Asgarian

Electronic Thesis and Dissertation Repository

Electroencephalography (EEG) has been widely used to record electromagnetic fields for motor imagery (MI)-based brain-computer interfaces (BCIs). However, collecting MI signals is often time-consuming and challenging to classify due to the inter-subject variability of EEG signals. To address these issues, we propose a novel framework MACNet, which stands for Multi-view Adversarial Contrastive Network. MACNet employs a contrastive learning approach to learn spatial and temporal features in two views, using Riemannian and Euclidean encoders. By jointly extracting underlying features and learning domain-invariant representations in both source and target features, MACNet improves the alignment and accuracy. In addition, we propose a domain …

Transferring Organelles Into Native Neurons: A Disease-Modifying Therapy For Neurodegenerative Disorders, Lohiny Balendran

Electronic Thesis and Dissertation Repository

Currently, there are no disease-modifying therapies to counter the progression of neurodegenerative diseases that are associated with mitochondrial dysfunction in the early stages. In this study, we have used a novel strategy of cell fusion to transfer mitochondria from one cell to another using fusogens (syncytin 1 and syncytin 2). Syncytins are placental proteins encoded by endogenous retroviral envelope genes that promote cellular fusion. In this study, we have proposed that donor cells engineered to stably express syncytin when cocultured with recipient cells will allow fusion and facilitate the transfer of mitochondria into recipient cells. Syncytin-mediated systems revealed about 16.6-18.5% …

The Synthesis And Characterization Studies Of Modified Nucleobase In Pna And Dna, Gyeongsu Park

Electronic Thesis and Dissertation Repository

Nucleic acids have been extensively studied not only for their importance in biological systems as the medium of genetic information but also for their potential uses in therapeutic, diagnostic and other biological applications. As such, modified oligonucleotides and oligonucleotide analogues have drawn the attention of researchers from various disciplines. Modification of oligonucleotides can enhance their desired characteristics and engender unique properties, such as fluorescence, giving rise to a variety of applications. Peptide nucleic acid (PNA) is an oligonucleotide mimic with a pseudo-peptide backbone based on N-(2-aminoethyl)glycine that is renowned for high target binding affinity and resistance to enzyme degradation. …

Vertebral Endplate Structural Defects: Measurement, Prevalence And Associated Factors, Aliyu Lawan

Electronic Thesis and Dissertation Repository

Objective: To synthesize current knowledge on the association of endplate structural defects (EPSD) with back pain (BP), improve EPSD measurement, and investigate EPSD prevalence, distribution, and association with age and body mass index (BMI).

Methods: In study 1, a systematic review was conducted on five databases for studies reporting on the association between EPSD and BP. Studies 2 and 3 used CTs and mCTs of 19 embalmed cadavers to examine the diagnostic accuracy of common EPSD assessment methods, and to develop and validate a novel method. Study 4 used the novel method on 200 adult males’ MRI to estimate EPSD …

Sarcopenia In Head And Neck Cancer: A Prognostic Analysis, Nedeljko Jovanovic

Electronic Thesis and Dissertation Repository

Introduction: In head and neck cancer (HNC), loss of skeletal muscle mass (SMM), or sarcopenia, is a strong prognostic factor for outcomes. However, inconsistencies in its assessment limit our understanding of the relationship between sarcopenia and nutrition-related outcomes. This project evaluated the significance of sarcopenia as described in the literature and as demonstrated in a cohort of HNC patients.

Methods: A scoping review was first conducted followed by a retrospective cohort study with data collected from 194 oropharyngeal carcinoma patients treated with definitive radiation/chemoradiation. Sarcopenia was assessed from computed tomography (CT) imaging at the third cervical vertebra (C3) and the …

Differences In Startle And Prepulse Inhibition In Contactin-Associated Protein-Like 2 Knock-Out Rats Are Associated With Sex-Specific Alterations In Brainstem Neural Activity, Alice Zheng, Kaela E Scott, Ashley L Schormans, Rajkamalpreet Mann, Brian L Allman, Susanne Schmid

Anatomy and Cell Biology Publications

The contactin-associated protein-like 2 (CNTNAP2) gene encodes for the CASPR2 protein, which plays an essential role in neurodevelopment. Mutations in CNTNAP2 are associated with neurodevelopmental disorders, including autism spectrum disorder and schizophrenia. Rats with a loss of function mutation in the Cntnap2 gene show increased acoustic startle response (ASR) and decreased prepulse inhibition (PPI). The neural basis of this altered auditory processing in Cntnap2 knock-out rats is currently unknown. Auditory brainstem recordings previously revealed no differences between the genotypes. The next step is to investigate brainstem structures outside of the primary auditory pathway that mediate ASR and PPI, which are …

A Comparison Of Methods To Identify The Mean Response Time Of Ramp-Incremental Exercise For Exercise Prescription, Nikan Behboodpour

Electronic Thesis and Dissertation Repository

Introduction: The oxygen uptake (V̇O₂) vs power output (PO) relationship from ramp incremental exercise (RAMP) is used to prescribe aerobic exercise. As PO increases, there is a delay in V̇O₂ that contributes to a misalignment of V̇O₂ from PO making precise prescription of exercise PO untenable. Three methods of determining Mean Response Time (exponential modeling (MRT_EXP), linear modeling (MRT_LIN), and the steady-state method (MRT_SS)) were compared and evaluated for their accuracy at predicting the V̇O₂ associated with two PO below estimated lactate threshold (q_LT) and one …

Characterizing Maternal Isolation-Induced Ultrasonic Vocalizations In A Gene-Environment Interaction Rat Model For Autism., Dorit Möhrle, Megan Yuen, Alice Zheng, Faraj L Haddad, Brian L Allman, Susanne Schmid

Anatomy and Cell Biology Publications

Deficits in social communication and language development belong to the earliest diagnostic criteria of autism spectrum disorders. Of the many risk factors for autism spectrum disorder, the contactin-associated protein-like 2 gene, CNTNAP2, is thought to be important for language development. The present study used a rat model to investigate the potential compounding effects of autism spectrum disorder risk gene mutation and environmental challenges, including breeding conditions or maternal immune activation during pregnancy, on early vocal communication in the offspring. Maternal isolation-induced ultrasonic vocalizations from Cntnap2 wildtype and knockout rats at selected postnatal days were analyzed for their acoustic, temporal and …