Digital Commons Network^™

The Lotus Japonicus Short Internodes/Stylish Gene Family And Its Role During Root Nodule Development, Arina Shrestha

Electronic Thesis and Dissertation Repository

The ability to host nitrogen-fixing bacteria, which convert atmospheric di-nitrogen to ammonia, inside root cells is a special adaptation of most leguminous and only some non-leguminous plants. It engenders the development of new, root-derived organs, called nodules. Significant research effort has been dedicated to understanding how these ultimate nitrogen-fixing plant organs are built. Nonetheless, important gaps with respect to pertinent knowledge still remain.

My thesis work has focused on deciphering the role of the SHORT INTERNODES/STYLISH (SHI/STY) transcription factor gene family during nodule formation in Lotus japonicus, a model legume plant. I show here that the SHI/STY …

Mass Spectrometry-Based Proteomics Analysis Of Bioactive Proteins In Emd That Modulate Adhesion Of Gingival Fibroblast To Improve Bio-Integration Of Dental Implants, David Zuanazzi Machado Jr

Electronic Thesis and Dissertation Repository

Titanium implants are used in dental practice to replace damaged or lost teeth. The implant needs to integrate with the surrounding gingiva to protect it against bacterial invasion that leads to implant loss. The biointegration is dependent on the implant surface that interacts with proteins from biological fluids to modulate tissues response. Tailoring the surface with specific proteins from the enamel matrix derivative (EMD) would be beneficial to improve the implant-gingiva interface since EMD can affect various cells including gingival fibroblasts. A surface-affinity approach using three different titanium surfaces and saliva was utilized as a model in combination with tandem …

Translational Control Of Stress Induced Breast Cancer Plasticity, Michael Jewer

Electronic Thesis and Dissertation Repository

Cancer cell plasticity, whereby stem-cell-like properties are acquired in response to stress, represents a major challenge in cancer treatment. Using cell line and patient-derived xenograft (PDX) models, we demonstrate that translational reprogramming occurs in response to stresses such as hypoxia and chemotherapy which elicits stem cell properties in breast cancer. Other stresses like chemotherapy demonstrate the translational inhibition that has been well characterized as an integral hypoxic cellular response. The inhibition of translation is primarily regulated at initiation by mTOR/4E-BP1 and PERK/eIF2α signalling. We identify previously undescribed 5’ untranslated regions (5’UTRs) of plasticity-associated genes like NANOG, SNAIL and NODAL. …

Cell Recruitment And Differentiation In Wound Repair, John Walker

Electronic Thesis and Dissertation Repository

Chronic wounds represent a major health problem primarily affecting patients with underlying pathologies including diabetes and vasculopathy. These wounds are characterized by an impaired transition from the inflammatory to the proliferative phase of healing. In this thesis, the complex relationship between cells and their microenvironment was explored in the context of wound healing by investigating how intrinsic differences in fibroblasts affect their response to external stimuli, and how extracellular matrix (ECM) proteins modify cellular responses during acute wound repair. First, it was hypothesized that different subpopulations of fibroblasts could be identified in cutaneous tissue based on divergent embryonic expression patterns …

Cortical Plasticity Following Adult-Onset Hearing Loss, Ashley L. Schormans

Electronic Thesis and Dissertation Repository

The consequences of hearing loss are not confined to how the central auditory system processes sound; crossmodal plasticity also occurs, which is characterized by an increased responsiveness of neurons in auditory areas to visual and/or tactile stimuli. In the primary auditory cortex, partial hearing loss causes a decrease in the number of auditory-responsive neurons, as well as an increase in multisensory neurons. However, it was relatively unknown how adult-onset hearing loss affected cortical areas that are already capable of integrating multisensory information, such as the lateral extrastriate visual cortex (V2L). Using a combination of in vivo electrophysiology, neuropharmacology and behavioural …

Partial Characterization Of Putative Cyp86a Genes From Soybean, Trish Tully

Electronic Thesis and Dissertation Repository

Soybean (Glycine max [L.] Merr.) is a globally cultivated crop that is important to the sustainability of many industries. However, like all plants, optimal cultivation of soybean is threatened by detrimental environmental factors. For example, high yield of soybean is threatened by soil-borne pathogens like Phytophthora sojae. Resistance against P. sojae was previously positively correlated with aliphatic suberin deposition in soybean. As such, a deeper understanding of the biosynthesis of suberin may assist in engineering a resistant form of soybean, based on enhanced suberin content. In soybean, the ω-OH fatty acid monomers are predominant and most strongly correlated …

Quantitative Proteome Analysis Of Alfalfa In Drought Stress Under The Influence Of Mir156, Alpa Puri

Electronic Thesis and Dissertation Repository

Medicago sativa is one of the most produced perennial forage crops in Canada. Drought stress is a major form of abiotic stress affecting the productivity and annual yield of alfalfa. A small noncoding RNA, miR156 has a role in abiotic stress tolerance, while regulating downstream SPL genes. In this study, whole leaf proteome and amino acid concentrations of miR156OE (A8) genotype of alfalfa under drought stress were quantified. In results, 3,000 proteins groups were identified using MaxQuant when searched against Medicago truncatula protein sequence database. Gene ontology analysis showed enriched proteins were involved in biological and molecular processes such as …

Contrasting Non-Breeding Ecology Of Swainson’S Thrush (Catharus Ustulatus) In Andean Forest And Shade-Grown Coffee Plantations, Sean Mcelaney

Electronic Thesis and Dissertation Repository

Shade-grown coffee plantations provide Neotropical migratory birds an alternative to primary growth forest which is disappearing throughout their non-breeding range. However, it remains unclear whether plantations can provide enough structure to maintain viable non-breeding populations of many species. I studied Swainson’s Thrush (Catharus ustulatus) in the Colombian Andes in a mixture of montane forest and shade-grown coffee plantation. In comparing the two habitats I looked at factors indicative of habitat quality, such as age/sex hierarchies, area of concentrated use, density, diet, and migration timing. My research aimed to determine whether Neotropical migrants benefit from this agroecosystem, and to …

The Group A Streptococci Bacteriocins Facilitate A Competitive Advantage During Nasopharyngeal Infection, Lana Estafanos

Electronic Thesis and Dissertation Repository

Pathogenic streptococci have evolved specific systems to eliminate bacterial competitors within their biological niche. In microbial environments, niche competition is often driven by the production of short antimicrobial peptides called bacteriocins; this provides a mechanism by which Streptococcus pyogenes may compete for ecological stability and establish infection. Recent findings from our laboratory have identified two novel Class IIb bacteriocin systems – Streptococcus pyogenes bacteriocin (Spb) JK and MN in the M18 serotype S. pyogenes strain MGAS8232 – that may contribute to nasopharyngeal infection. Here, we show that galactose and CO₂ are distinct regulatory cues which induce antimicrobial activity. Under …

Uncovering A Mystery Of The Isoflavonoid Metabolon: Identification And Characterization Of The Arogenate Dehydratase Gene Family In Soybean, Kelsey Pannunzio

Electronic Thesis and Dissertation Repository

Soybean (Glycine max) is a vastly important, multi-billion dollar global commodity; but this crop’s yields are under threat from the pathogen Phytophthora sojae, which causes extensive stem and root rot in soybean crops. Isoflavonoids, a metabolite class unique to legumes, are a promising research target to combat P. sojae. Isoflavonoids are released as phytoalexins in response to stress, and also facilitate interactions with nitrogen-fixing rhizobial bacteria through nodule formation. An isoflavonoid biosynthesis metabolon was discovered in soybean through co-immunoprecipitation, anchored to the endoplasmic reticulum by isoflavone synthase (IFS) and Cinnamate 4-hydroxylase, two cytochrome P450 enzymes. One of the …

Alpha-Synuclein Toxicity Is Caused By Mitochondrial Dysfunction, Michael G. Tauro

Electronic Thesis and Dissertation Repository

Parkinson’s disease (PD) is the second most common neurodegenerative disorder, affecting roughly 1% of the population over the age of sixty years. Alpha-synuclein (aSyn) is a protein implicated in both familial and idiopathic forms of PD, yet despite the wealth of data implicating aSyn as a causative agent in PD, the mechanisms underlying its toxicity remain mostly unknown. Mitochondrial dysfunction is a major hallmark of PD, yet there is only limited evidence linking aSyn toxicity to mitochondrial dysfunction. My study establishes a novel aSyn model in respiring yeast cells, which allows me to explore how aSyn affects mitochondrial homeostasis and …

Novel Insights Into The Genomic Integration Site Landscape Of Hiv-1 And Other Retrovirus Genera, Hinissan P. Kohio

Electronic Thesis and Dissertation Repository

An important event during infection by retroviruses such as human immunodeficiency virus type 1 (HIV-1) is the permanent integration of the viral genome into the host genome. This event leads to life-long infection and is accompanied by a period of quiescence/latency ranging from a few years to >10 years where HIV-1 expression is barely detectable or undetectable. Despite the use of combination antiretroviral therapy (cART) which controls HIV-1 infection, quiescent/latent virus presents a major obstacle towards a functional cure. Integration site location in the genome is thought to contribute to latent infections and has the potential to confound anti-latency treatments, …

The Leucine-Rich Domain Of Rgnef: A Modifier Of Tdp-43 Toxicity In Drosophila Melanogaster., Benjamin Martin Withers

Electronic Thesis and Dissertation Repository

Abstract

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the progressive degeneration of motor neurons. Rho Guanine Nucleotide Exchange factor (RGNEF) like other RNA-binding proteins, has been observed to form inclusions in the spinal cord motor neurons of both sporadic and familial cases of ALS. RGNEF has been determined to be a pro-survival factor under stress conditions. When comparing expression of different constructs of RGNEF in HEK293T cells, a Leucine-rich domain containing fragment of RGNEF (L-Rich) was found to form aggregates under metabolic stress that co-aggregated with TDP-43, another ALS-linked RNA-binding protein.

In this thesis, I used both …

The Role Of H3k4 Methyltransferases In Drosophila Memory, Nicholas Raun

Electronic Thesis and Dissertation Repository

Gene transcription required for long-term memory requires the modification of histones. However, there are still many uncertainties about the identity and spatial expression of genes regulated by histone modifications during memory related processes. In this project I examined the role of Drosophila melanogaster methyltransferases Set1 and trx in courtship memory. Genetic knockdown of Set1 and trx in the mushroom body (MB) revealed that Set1 was necessary for short- and long-term memory, while trx was only required for long-term memory. Transcriptional profiling of MBs following trx-knockdown revealed expression changes in MB-enriched genes and genes involved in RNA processing. Among the …

Investigating The Role Of Tp53inp1 And Tp53inp2 In Neuronal Autophagy And Mitophagy, Vidhyasree Shyam

Electronic Thesis and Dissertation Repository

Autophagy is highly conserved cellular process that functions in ensuring the turnover of proteins and organelles in a number of different cell types. Mitophagy is a selective form of autophagy which serves to target and rid the cell of damaged or superfluous mitochondria. The process is central to preventing the accumulation of defective mitochondria and is particularly important in neurons, which rely exclusively on mitochondria to sustain their immense metabolic needs. Dysregulation of autophagy is believed to contribute to the neurodegeneration seen in such disorders as Parkinson’s disease and cerebral ischemia. However, further understanding of the role of neuronal autophagy …