Induction Of Alternative Pathway Respiration By Nitrate In Chlamydomonas, Shanmugasundaram Pakkiriswami

Electronic Thesis and Dissertation Repository

Abstract

Besides the ubiquitous cytochrome pathway of mitochondrial respiration, the green algae Chlamydomonas reinhardtii possesses an alternative pathway of respiration, which is comprised of a single protein, alternative oxidase (AOX). AOX is induced when C. reinhardtii cells are shifted from a growth medium containing ammonium as the nitrogen source to one with nitrate. The primary aim of this thesis was to understand the metabolic connections between nitrate assimilation and the induction of the alternative pathway. That these two metabolic processes are closely linked is supported by the fact that a gene encoding AOX (AOX1) is clustered with the …

The Neural Mechanisms Underlying The Perception And Production Of Learned Vocalizations In Songbirds, Shannon Katie Mischler

Electronic Thesis and Dissertation Repository

Songbirds produce a wide array of vocalizations, including song, and learned and innate calls. Songs and calls can be functionally defined. Songs are typically used to attract potential mates and defend one’s territory, whereas calls are used for everything else, such as advertising the presence of a predator, or location of a food source, and maintaining contact with members of one’s flock. The purpose of this thesis was to better understand the neural mechanisms underlying call production and perception in two songbird species; the black-capped chickadee (Poecile atricapillus) and the zebra finch (Taeniopygia guttata). My objectives …

Role Of High Molecular Weight Hyaluronan In Ultraviolet B Light-Induced Transformation, Katelyn Cousteils

Electronic Thesis and Dissertation Repository

Keratinocyte carcinomas (KCs) are the most common cancers globally. Ultraviolet light is the key risk factor for these cancers but sunscreen has proven ineffective in their prevention, indicating a need for new prophylactic agents. Chronic elevation of high molecular weight (HMW) tissue hyaluronan (HA) in skin is linked to tumor resistance in the naked mole rat. To directly assess the role of this polysaccharide in resistance to keratinocyte tumors, a HMW HA phosphatidylethanolamine (HA-PE) formulation that penetrates skin and accumulates as coats around keratinocytes was prepared. The tumor resistance properties of the HA-PE formulation were tested in a mouse model …

Characterization Of Plant-Spider Mite Interactions And Establishment Of Tools For Spider Mite Functional Genetic Studies, Nicolas Bensoussan

Electronic Thesis and Dissertation Repository

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most polyphagous herbivores feeding on cell contents of over 1100 plant species including more than 150 crops. However, despite its important pest status and a growing understanding of the molecular basis of its interactions with plant hosts, knowledge of the way mites interface with the plant while feeding and the plant damage directly inflicted by mites is lacking. Likewise, while the use of the reverse genetic tools in plants facilitated our understanding of the establishment of defense mechanisms against spider mite herbivory, such tools are lacking for …

The Mystery Of Nuclear Localization Of Arogenate Dehydratase5 From Arabidopsis Thaliana, Sara Abolhassani Rad

Electronic Thesis and Dissertation Repository

Arogenate dehydratases (ADTs) have been identified to catalyze the last step of phenylalanine (Phe) biosynthesis in plants. All ADTs have a transit peptide sequence that targets them into the chloroplasts where the biosynthesis of Phe happens. Subcellular localization studies using fluorescently tagged Arabidopsis thaliana ADTs demonstrated that all six ADTs localize to chloroplast stromules (stroma filled tubules). However, one member of this family, ADT5, was also detected in the nucleus. As dual targeting of proteins to different cell compartments is an indication of multifunctionality, ADT5 nuclear localization suggests that this member of the ADT protein family is a moonlighting protein …

A Pilot Study On The Affective Responses To Watching Consecutive Episodes Of A Television Show During Aerobic Exercise Below The Ventilatory Threshold, Lauren Crutchlow

Electronic Thesis and Dissertation Repository

A quasi-experimental pilot study determined whether restricting television-watching to treadmill walking below the ventilatory threshold improved affective valence, perceived activation, enjoyment, attentional focus, and intention to bundle television-watching with exercise. Eleven inactive, young adults (21.18 + 1.47 years) in post-secondary education performed two 40-minute exercise tests, wherein aforementioned outcomes were repeatedly assessed. Participants in the experimental group (n=4) watched the first episode of a television show between exercise tests and the second episode of the same television show during the second exercise test. Analyses revealed large, non-significant multivariate intervention effects on affect and attention outcomes, a large, significant univariate intervention …

Behaviour Change Intervention Strategies To Prevent Excessive Gestational Weight Gain In Pregnant Women Using A Nutrition And Exercise Lifestyle Intervention Program (Nelip), Karishma Hosein

Electronic Thesis and Dissertation Repository

Maternal obesity and excessive gestational weight gain (EGWG) are associated with adverse maternal and fetal outcomes. To evaluate the effectiveness of different behaviour change intervention strategies, it was hypothesized that the introduction of a single behaviour change, followed by a second, would be more effective at preventing early and total EGWG in pregnant women compared to the early simultaneous introduction of both behaviour changes. Eighteen pregnant women were block randomized into one of 3 Nutrition and Exercise Lifestyle Intervention Program (NELIP) strategies (full NELIP, Nutrition followed by Exercise N+E, Exercise followed by Nutrition E+N) and were followed at weekly face-to-face …

Characterization Of Acaricide Resistance, Plant-Mediated Rnai Against Two-Spotted Spider Mites (Tetranychus Urticae Koch), And Assessing Off- And Non-Target Effects, Hooman Hosseinzadeh Namin

Electronic Thesis and Dissertation Repository

The two-spotted spider mite (TSSM), Tetranychus urticae (Koch), is one of the most damaging agricultural pests in the world. It feeds on over 150 crops, causing considerable yield losses in greenhouses and agricultural fields. Currently, using synthetic acaricides is the main method to control TSSM. However, it can develop resistance to acaricides with repeated exposure, and typically resistance can occur within two to four years. To understand the underlying mechanisms of spider mite adaptation to acaricides is an essential part of resistance management strategy. The resistance ratio of the pyridaben-selected strain compared with the pre-selection strain was estimated at greater …

Urea As An Effective Nitrogen Source For Cyanobacteria, Kevin J. Erratt

Electronic Thesis and Dissertation Repository

Urea use has grown substantially in the past half-century, with urea now accounting for > 50% of nitrogen fertilizer applications worldwide. The shift from inorganic nitrogen fertilizers to urea-based sources has coincided with the reappearance of cyanobacteria blooms in freshwaters. Here, we examined urea as a nitrogen source for three bloom-forming cyanobacteria species. We found that (1) urea was consumed more rapidly relative to inorganic nitrogen substrates, suggesting that cyanobacteria exhibit a preference for urea; (2) urea was consumed in excess of cellular requirements; and (3) urea may offer cyanobacteria a competitive edge over eukaryotic algae by enhancing light absorption capabilities. …

Ccn Proteins In Metastatic Melanoma, James Hutchenreuther

Electronic Thesis and Dissertation Repository

Melanoma cells recruit host tissue to become a part of the activated tumour stroma. This stromal microenvironment is similar to that seen in fibrotic tissue. CCN1 and CCN2 are tightly spatiotemporally regulated matricellular proteins involved in development and wound healing, and are abberantly expressed in fibrosis. Additionally they have been seen to be abnormally highly expressed in several cancers, including melanoma. Recent evidence has shown that deletion of CCN2 in the fibroblasts renders mice resistant to several models of fibrosis. Given this, I tested the hypothesis that deletion of CCN1 and CCN2 from fibroblasts could similarly impede the formation of …

An Investigation Of The Ck2-Dependent Phosphoproteome Using Inhibitor Refractory Ck2-Alpha, Edward Cruise

Electronic Thesis and Dissertation Repository

Protein kinase CK2 is a constitutively active serine/threonine kinase that is overexpressed in several human cancers, and by virtue of the vast number of putative substrates in the phosphoproteome, is implicated in the regulation of numerous cellular processes. Consequently, CK2 is an emerging therapeutic target with many CK2 inhibitors having been developed. An example of one such inhibitor is the clinical stage compound CX-4945. Although highly selective for CK2, the ATP competitive CX-4945 has demonstrated affinity for other kinases. Unique features of the catalytic pocket of CK2 have allowed for the development of inhibitor refractory mutants, which have since been …

No Evidence That Binocular Vision Enhances Online Corrections For Reaches In The Lower-Visual Field, Jennifer N. Campbell

Electronic Thesis and Dissertation Repository

Some work has proposed that an increased density of retinal ganglion cells in the superior hemiretina elicits a functional advantage for goal-directed reaches in the lower visual field (i.e., loVF). Furthermore, reaches performed with binocular stereo-cues exhibit optimized feedback-based trajectory corrections (i.e., online control). The present study examined whether the purported loVF advantage is restricted to binocular reaches implemented via a primarily online mode of control. Participants completed binocular and monocular reaches to loVF and upper-visual field (i.e., upVF) targets. Separate groups were provided vision during response planning and control (i.e., closed-loop group: CL), or during response planning only (i.e., …

The Effect Of Diet On Midgut And Resulting Changes In Infectiousness Of Acmnpv Baculovirus In Trichoplusia Ni, Elizabeth Chen

Electronic Thesis and Dissertation Repository

The cabbage looper, Trichoplusia ni, a global generalist lepidopteran pest, has developed resistance to many synthetic and biological insecticides, requiring effective and environmentally acceptable alternatives. One possibility is the Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV). This baculovirus is highly infectious for T. ni, with potential as a biocontrol agent, however, its effectiveness is strongly influenced by dietary context. In this study, microscopy and transcriptomics were used to examine how the efficacy of this virus was affected when T. ni larvae were raised on different diets. Larvae raised on potato host plants had lower chitinase and chitin deacetylase transcript levels …

The Lasting Effects Of Perceived Predation Risk On The Avian Brain And Behaviour, Lauren E. Witterick

Electronic Thesis and Dissertation Repository

Predators affect prey populations not only through direct killing, but also through perceived predation risk – the ‘fear’ of predators. Responding to predation risk is critical for prey survival, however perceived predation risk can have lasting effects ranging from individual changes in neurobiology up to population level effects. I manipulated perceived predation risk using auditory playbacks of predators or non-predators in wild caught black-capped chickadees (Poecile atricapillus) in acoustic isolation and wild caught brown-headed cowbirds (Molothrus ater) in large outdoor aviaries. I found changes in dendritic morphology and inhibited neurogenesis in response to increased perceived predation risk lasting at …

Regulation Of C-Raf Stability By The Ranbpm/Ctlh Complex, Christina J. Mctavish

Electronic Thesis and Dissertation Repository

RanBPM is an evolutionarily conserved multi-domain protein that has been implicated in the regulation of several cellular process, including protein stability, cell migration, gene transcription, and apoptosis. RanBPM is identified as a key member of the CTLH complex, an orthologous complex to a yeast E3 ubiquitin ligase complex, the exact function of which remains unknown. Previously, our laboratory identified RanBPM as an inhibitor of the ERK1/2 pathway through the modulation of C-RAF protein levels. This study shows that RanBPM-mediated degradation of C-RAF occurs through the proteasome and the entire CRA domain of RanBPM is necessary for direct interaction with C-RAF …

Bioinformatics And Next Generation Sequencing: Applications Of Arthropod Genomes, Zaichao Zhang

Electronic Thesis and Dissertation Repository

Over the past decade, the Next Generation Sequencing (NGS) technology has been broadly applied in many areas such as genomics, medical diagnosis, biotechnology, virology, biological systematics, forensic biology, and anthropology. Taken together, it has offered us brilliant insights into life sciences. Most of the work presented in this thesis describes NGS applications on genome assembly, genome annotation, and comparative genomics, using arthropods as case studies: (1) by sequencing and analyzing the genomes of three Tetranychus spider mites with three completely different feeding behaviors, we uncovered genomic signature variations and indicative of pest adaptations; (2) we sequenced, assembled and annotated five …

Role Of The Swi/Snf Chromatin Remodelling Complex In The Axon Development Of The Drosophila Mushroom Body, Melissa C. Chubak

Electronic Thesis and Dissertation Repository

The SWI/SNF complex is an evolutionarily conserved ATP-dependent chromatin remodelling complex that has been implicated in the aetiology of intellectual disability (ID). Among the dominant ID genes, the SWI/SNF complex is the most highly enriched protein complex. However, its role in the nervous system is not yet understood. I systematically investigated the role of this complex in the development of the Drosophila mushroom body (MB), a complex brain structure required for learning and memory. Gross MB morphology was assessed using confocal microscopy to identify morphological defects following RNAi-mediated knockdown of the 15 individual SWI/SNF genes in the MB. Knockdown of …

The Genetic And Environmental Basis For Chc Biosynthesis In Drosophila, Heather Ke Ward

Electronic Thesis and Dissertation Repository

Cuticular hydrocarbons (CHCs) are produced by insects and primarily used to prevent desiccation. In Drosophila, certain compounds have secondary roles as infochemicals that may act during courtship to influence mate choice. Certain CHCs may stimulate courtship with heterospecifics or act to repel conspecifics. The CHC profile produced by an individual is the result of the interaction between its genetic background and the environment, though the genes that underlie species differences in CHC production and how the environment can modulate the abundance of individual compounds within a species is not well known. Here, candidate gene CG5946 was found to be …

Differential Functional Roles Of Aldh1a1 And Aldh1a3 In Mediating Metastatic Behavior And Therapy Resistance Of Human Breast Cancer Cells, Alysha K. Croker, Mauricio Rodriguez-Torres, Ying Xia, Hon Sing Leong, Siddika Pardhan, John D. Lewis, Alison L. Allan

Anatomy and Cell Biology Publications

Previous studies indicate that breast cancer cells with high aldehyde dehydrogenase (ALDH) activity and CD44 expression (ALDHhiCD44+ ) contribute to metastasis and therapy resistance, and that ALDH1 correlates with poor outcome in breast cancer patients. The current study hypothesized that ALDH1 functionally contributes to breast cancer metastatic behavior and therapy resistance. Expression of ALDH1A1 or ALDH1A3 was knocked down in MDA-MB-468 and SUM159 human breast cancer cells using siRNA. Resulting impacts on ALDH activity (Aldefluor® assay); metastatic behavior and therapy response in vitro (proliferation/adhesion/migration/colony formation/chemotherapy and radiation) and extravasation/metastasis in vivo (chick choroiallantoic membrane assay) was assessed. Knockdown of ALDH1A3 …

Elevated Temperature And Co2 Concentrations Affect Carbon Flux In Two Boreal Conifers, Sasha Madhavji

Electronic Thesis and Dissertation Repository

Elevated temperatures and CO₂ will alter carbon flux in two dominant boreal tree species Picea mariana (black spruce) and Larix laricina (tamarack). Trees were grown in three temperature treatments (ambient, ambient +4 °C, and ambient +8 °C) at either 400 ppm or 750 ppm CO₂, to simulate climate conditions between now and the year 2100. Spruce acclimated to increasing temperature detractively; warming scenarios reduced spruce net carbon gain. Tamarack maintained comparable levels of net photosynthesis (A_net) across warming treatments and both species acclimated respiration (R_dark) with increasing growth temperature. Elevated CO₂-grown …

Identifying Electrophysiological Components Of Covert Awareness In Patients With Disorders Of Consciousness, Geoffrey Laforge

Electronic Thesis and Dissertation Repository

Naturalistic stimuli evoke synchronous patterns of neural activity between individuals in sensory and higher cognitive, “executive” networks of the brain. fMRI paradigms developed to measure this inter-subject synchronization have been extended to test for executive processing in behaviourally non-responsive patients as a neural marker of awareness. This thesis adapted one such paradigm for use in EEG, a low-cost, portable neuroimaging technique that can be administered at a patient’s bedside. Healthy participants listened to a suspenseful auditory narrative during EEG recording. Significant inter-subject synchronization was found throughout the audio but was significantly reduced during a scrambled control condition. This paradigm was …

Expedited Radiation Biodosimetry By Automated Dicentric Chromosome Identification (Adci) And Dose Estimation, Peter Rogan, Ben Shirley, Yanxin Li, Joan Knoll

Biochemistry Publications

Biological radiation dose can be estimated from dicentric chromosome frequencies in metaphase cells. Performing these cytogenetic dicentric chromosome assays is traditionally a manual, labor-intensive process not well suited to handle the volume of samples which may require examination in the wake of a mass casualty event. Automated Dicentric Chromosome Identifier and Dose Estimator (ADCI) software automates this process by examining sets of metaphase images using machine learning-based image processing techniques. The software selects appropriate images for analysis by removing unsuitable images, classifies each object as either a centromere-containing chromosome or non-chromosome, further distinguishes chromosomes as monocentric chromosomes (MCs) or dicentric …

Phosphorylation Of Tau Protein At Thr175 Is A Toxic Event Associated With Neurodegeneration, Alexander Moszczynski

Electronic Thesis and Dissertation Repository

Aberrant phosphorylation and pathological deposition of the microtubule associated protein tau (tau protein) is associated with toxicity and cellular death in a number of neurodegenerative diseases (tauopathies). Specific phosphorylation sites are of interest in the processes leading to tau protein toxicity. One site of interest on tau protein is Thr¹⁷⁵ (pThr¹⁷⁵), which has been identified in diseased brain tissue from individuals with amyotrophic lateral sclerosis with cognitive impairment (ALSci) and Alzheimer’s disease. In vitro, pseudophosphorylation at this residue has been shown to induce the formation of pathological tau fibrils and, apoptotic cell death.

In my thesis, …

Examination Of Bcaa Transport And Synthesis In Staphylococcus Aureus, Julienne Kaiser

Electronic Thesis and Dissertation Repository

Staphylococcus aureus is a human pathogen capable of causing infections that range from mild skin and soft tissue infections to severe infections of the bone, muscle, heart, and lung. To survive and thrive in such diverse host environments, S. aureus must maintain sufficient levels of metabolites and cofactors to support virulence determinant production and replication. The branched-chain amino acids (BCAAs; Ile, Leu, Val) represent an important group of nutrients for S. aureus metabolism, as they are required for protein synthesis and synthesis of membrane branched-chain fatty acids (BCFAs), which are important for S. aureus environmental adaptation. Moreover, the BCAAs are …

Spatial And Temporal Epithelial Ovarian Cancer Cell Heterogeneity Impacts Maraba Virus Oncolytic Potential, Jessica G. Tong, Yudith Ramos Valdes, Milani Sivapragasam, John W. Barrett, John C. Bell, David Stojdl, Gabriel E. Dimattia, Trevor G. Shepherd

Anatomy and Cell Biology Publications

Background: Epithelial ovarian cancer exhibits extensive interpatient and intratumoral heterogeneity, which can hinder successful treatment strategies. Herein, we investigated the efficacy of an emerging oncolytic, Maraba virus (MRBV), in an in vitro model of ovarian tumour heterogeneity. Methods: Four ovarian high-grade serous cancer (HGSC) cell lines were isolated and established from a single patient at four points during disease progression. Limiting-dilution subcloning generated seven additional subclone lines to assess intratumoral heterogeneity. MRBV entry and oncolytic efficacy were assessed among all 11 cell lines. Low-density receptor (LDLR) expression, conditioned media treatments and co-cultures were performed to determine factors impacting MRBV oncolysis. …

Deciphering Sulfur Amino Acid Metabolism In Developing Seeds Of Common Bean, Jaya Joshi

Electronic Thesis and Dissertation Repository

With increasing food insecurity in the populated world, the number of people affected by chronic undernourishment is also increasing. Alone, protein energy malnutrition is linked to 6 million deaths annually. Despite being a good source of protein and dietary fibre, the quality of bean protein is limited because of sub optimal levels of essential sulfur amino acids: methionine and cysteine. Levels of cysteine and methionine in developing seeds have an inverse relationship with the non-protein sulfur amino acid S-methyl-cysteine (S-methylCys) and dipeptide g-glutamyl-S-methyl-cysteine (g-Glu-S-methylCys).

One of the strategies to improve protein quality in …

The Genetic Improvement Of Protein Quality In Common Bean (Phaseolus Vulgaris L.), Rosa Cecilia Viscarra Torrico

Electronic Thesis and Dissertation Repository

Abstract

The common bean (Phaseolus vulgaris L.) has a high seed protein content, between 20 and 30%. The protein quality in common is considered low because of the suboptimal levels of methionine and cysteine in the seed. Phaseolin, the main seed storage protein, accounts for 30-50% of the total seed protein content. Phaseolin only contains about 0.5 to 0.80% methionine. The suggested nutritional requirements for methionine-cysteine in the human diet are between 2.5 and 2.6 %. Previous studies on the germplasm SMARC1N-PN1 showed that deficiency in phaseolin and lectins leads to increased methionine-cysteine up to 2.6% in the bean …

Modelling Walleye Population And Its Cannibalism Effect, Quan Zhou

Electronic Thesis and Dissertation Repository

Walleye is a very common recreational fish in Canada with a strong cannibalism tendency, such that walleyes with larger sizes will consume their smaller counterparts when food sources are limited or a surplus of adults is present. Cannibalism may be a factor promoting population oscillation. As fish reach a certain age or biological stage (i.e. biological maturity), the number of fish achieving that stage is known as fish recruitment. The objective of this thesis is to model the walleye population with its recruitment and cannibalism effect. A matrix population model has been introduced to characterize the walleye population into three …

Amelioration Of Prenatal Alcohol Effects By Environmental Enrichment In A Mouse Model Of Fasd, Aniruddho Chokroborty-Hoque

Electronic Thesis and Dissertation Repository

Maternal alcohol consumption during pregnancy results in a spectrum of behavioural and cognitive deficits collectively known as Fetal Alcohol Spectrum Disorders (FASD). Currently, little is know about if and how the external environment may modulate these deficits. I have used C57BL/6 mice to study this interaction between prenatal alcohol exposure and the postnatal environment. Alcohol exposure during synaptogenesis produces high levels of anxiety-like traits and decreased memory performance. Alcohol-exposed mice (and matched unexposed controls) were put in 'environmentally-enriched' conditions of voluntary exercise, physical activities and cognitive stimulation to ascertain the effects of a positive postnatal environment. The results show that …

Expression And Characterization Of A Putative Βeta-Glycosidase From The Ginseng Pathogen Pythium Irregulare, Scarlett Puebla Barragan

Electronic Thesis and Dissertation Repository

A putative ginsenosidase (PiGH1-x) from the oomycete pathogen of American Ginseng, Pythium irregulare, was expressed in E. coli DH5α to assess its capability to partially deglycosylate ginsenosides. The recombinant protein was extracted using non-denaturing and denaturing conditions and purified using gel filtration chromatography and nickel affinity purification. Glycosidase activity was tested using p-nitrophenyl β-D-glucopyranoside (pNPG) as the substrate and measured through spectrophotometry. Ginsenosidase activity was tested using ginsenoside Rb1 as the substrate, reaction products were identified using LC-MS. Recombinant PiGH1-x cleaved glucose from pNPG, and converted ginsenoside Rb1 into Rd and Gypenoside XVII, demonstrating both (12) and (16) glycosidase activity. …