Digital Commons Network^™

Cholinergic Modulation Of Synaptic Plasticity In Vacht-Modified Mice, Rohit Kesarwani

Digitized Theses

The hippocampus is a region of the brain known for its role in learning and memory. The neural correlate of memory formation is believed to be changes in synaptic efficacy through processes broadly termed “synaptic plasticity”. Synaptic plasticity includes long term changes that increases (potentiation, LTP) or decreases (depression) synaptic strength. The hippocampus receives modulatory cholinergic afferents originating in the basal forebrain. This project investigates changes in bidirectional synaptic plasticity in gene-modified vesicular acetylcholine transporter protein-knockdown (VAChT-KD) mice, which express decreased acetylcholine secretion. Extracellular field recordings were performed on hippocampal slices to characterize synaptic physiology in the CA1- region glutamatergic …

Connexin36 Is A Negative Regulator Of Differentiation In Human Neuroblastoma Cells, Mandeep Sidhu

Digitized Theses

Gap junction channels permit intercellular communication through the passage of small molecules and metabolites between adjacent cells and are involved in regulating cellular processes such as homeostasis, differentiation, and proliferation. Connexins (Cx) are the constituent proteins of gap junctions and the neuronal connexin, Cx36, is highly expressed in the developing nervous system. In the present study, the effect of Cx36 on differentiation was investigated by manipulating Cx36 expression levels and inducing differentiation of SH-SY5Y cells. Following retinoic acid induced differentiation of SH- SY5Y cells, Cx36 mRNA expression increased, while Cx45 mRNA expression was unaffected. Cx36 overexpression resulted in diminished retinoic …

Do Brown-Headed Cowbirds Skew Host Offspring Sex Ratios Because They Are Large?, Robert Peter Decaire

Digitized Theses

Brood parasitism of song sparrow (Melospiza melodia) nests by brown-headed cowbirds (Molothrus ater) leads to a 50% reduction in the number of female offspring that survive to day 6 post-hatch and to fledging age. It has been proposed that this effect can be explained by size-based competition. The cowbird is larger than male sparrow nestlings, which are in turn larger than females. It is thought that the females cannot compete successfully against these two larger classes of nestling competitors, and suffer higher rates of mortality as a result. I tested this hypothesis by adding a large conspecific nestling to just-hatched …

Daily Flight Timing And Movement Strategies Of Migrating Landbirds: Importance Of Local Wind Patterns, Bethany Gloria Thurber

Digitized Theses

Although weather variation is known to affect migratory behaviours of landbirds, the specific effects of winds on flight timing and orientation at ecological barriers are not well understand. To assess seasonal effects of winds on flight timing at Long Point, Ontario, I compared estimates of daily arrival and departure to nocturnal radar counts. Landfall occurred later on nights with unfavourable versus favourable winds, and later on nights in spring versus fall. Daily arrival was positively associated with radar counts on nights with NE and SW winds, but variably associated otherwise. Departure timing could not be assessed. To investigate effects of …

Dna-Damage-Independent Mitochondrial Dysfunction Drives A Loss Of Retina Function Prior To Neuron Death In The Harlequin Mouse Model Of Aging, Alex Michael Laliberte

Digitized Theses

Although there are many aging-associated retinal diseases, the aging mechanisms which initiate retinal disease remain elusive. To investigate this problem, a model of premature aging, the harlequin mouse, was examined for deficits in retinal function, anatomy and histology, as well as changes in retinal oxidative stress, gene expression and mitochondrial DNA damage. Retinal function of the harlequin mouse, as assessed by electroretinography, was compromised in advance of change in retinal anatomy and histology. Functional deficits occurred in parallel with increased oxidative stress, assessed by in situ dihydroethidium staining. Furthermore, microarray transcriptome analysis of harlequin mice identified markers of mitochondrial stress, …

Enhancing The Maturation Of Dendritic Cells And Tracking Their Subsequent In Vivo Migration Using Cellular Magnetic Resonance Imaging, Sonali N. De Chickera

Digitized Theses

Dendritic cell (DC)-based cancer vaccines in clinical trials are promising, but their overall efficacy requires improvement. It is uncertain which DC subset, state of DC maturation/activation, and route of administration allow for optimum DC migration to lymph nodes (LNs) in vivo, thereby improving vaccine efficacy. A non-invasive imaging modality capable of tracking DC-based vaccine migration in patients would provide clinicians valuable information regarding these variables. A superparamagnetic iron oxide (SPIO) magnetic resonance imaging (MRI) contrast agent was used to label bone marrow-derived DCs (BMDCs) for tracking their subsequent migration using cellular MRI in a mouse model. Data indicate SPIO mechanically …

Investigating The In Vitro Effects Of Murine Clca3 On Ht29 Mucus And Goblet Cell Physiology, Evangelos Giakoumatos

Digitized Theses

The murine orthologue of the human calcium-activated chloride channel-1 protein (hCLCAl), mCLCA3, has been linked to regulating mucous properties due to its intimate association with mucin granule membranes of goblet cells. In particular, induced mCLCA3 expression via transgene introduction has been previously shown to significantly improve the intestinal Cystic Fibrosis (CF) phenotype in cystic fibrosis transmembrane conductance regulator- (Cftr) deficient mice, confirming its role as a modifier gene of CF. The specific biological or pathological function of the various CLCA members is unknown and their predicted role as ion channels has been disputed. The aim of this study was to …

Nicotine Has A Direct Effect On Brainstem Startle-Mediating Neurons, Farena S. Pinnock

Digitized Theses

Individuals with schizophrenia have impairments in prepulse inhibition of startle (PPI) which correlates with cognitive deficits. Nicotine improves the performance of patients and healthy individuals with PPI deficits on PPI tests. We hypothesized that nicotine directly affect startle-mediating neurons of the caudal pontine recticular nucleus (PnC) of the brainstem using electrophysiological recordings. The data revealed that nicotine (10 pM) increases leak current amplitude, reduces membrane resistance, and depolarizes the resting membrane potential. Nicotine had no significant effect on the EPSC amplitude for neither the trigeminal nor auditory stimulations. All effects were reversed only by a high dose (10 pM) of …

Natural History Of A Beetle-Yeast Association, Tanya E. Berkers

Digitized Theses

This project explores the ecology of the yeast Metschnikowia borealis, its relationship to the nitidulid beetle Conotelus obscurus and to nematodes found in the beetle. It was hypothesized that the yeasts parasitize the nematodes, and are therefore beneficial to the beetles. Adult beetle survival in the presence or absence of nematodes and M. borealis was assessed, as was larval yeast tolerance. Although the nematodes did decrease female beetles’ longevity, adult beetles with yeast did not survive longer than those without. Larvae require yeast but not specifically M. borealis. The adaptive value of the yeasts’ barbed spores therefore remains unclear. Previous …

Interactive Effects Of Warming And Nitrogen Deposition On Net Ecosystem Co2 Flux In A Temperate Old Field., Min Ku Kim

Digitized Theses

Global warming and increased atmospheric nitrogen deposition are expected to alter the carbon balances of ecosystems over the next century. My study measured net ecosystem CO2 exchange (NEE) in response to warming and nitrogen addition in a temperate old field using open system canopy chambers. Additionally, I assessed the indirect effects of warming and nitrogen addition on NEE caused by changes in aboveground productivity. In both 2009 and 2010, the study system was a net source of carbon, with the highest CO2 efflux during mid-summer. Warming and nitrogen addition did not affect NEE patterns in both years, notwithstanding a significant …

Thestudy Of Plume Ukaryotic Translation Initiation Factor 4e Genes For Plum Pox Virus Resistance, Xinhua Wang

Digitized Theses

Plum pox virus (PPV) causes the most economically-devastating viral disease in Prunus species, including fruit crops and ornamental species. Resistance through screening natural resistant germplasm has long been sought for the control of PPV but few natural resistance genes are available. Viruses encode only a limited number of proteins thus have to recruit host factors for their life cycles. This indicates that manipulating host factors is a potential approach for the development of virus resistance in plants. The present research focused on studying of plum (Prunus domestic L.) eukaryotic translation initiation factor 4E (eIF4E) and its isoform eIF(iso)4E genes for …

Control Of Muscle Fatty Acid Oxidation Capacity And Fatty Acid Transport Proteins In Migratory Birds: Effects Of . Photoperiod And Leptin, Daria M. Zajac

Digitized Theses

Avian migratory flights are fuelled by fatty acids. Fatty acid transporters and oxidative enzymes are seasonally upregulated in flight muscle to meet the demands of this intense exercise. The effect of photoperiod and leptin on fatty acid transporters and enzymes was studied in captive birds. Sparrows exposed to migratory photoperiods increased flight muscle FAT∕CD36 and H-FABP mRNA by 154% and 589% respectively, and had 32% higher H-FABP protein than birds in a non-migratory photoperiod. Migrants increased activities of flight muscle CPT, CS and HOAD by 57%, 23% and 74% respectively, and decreased LDH activity by 31%. Photoperiod manipulations did not …

Functional Characterization Of A Putative Wound-Induced P-Coumaro Yltyramine 3-Hydroxylase From Solanum Tuberosum, Stephanie Anderson

Digitized Theses

The conversion of p-coumaroyltyramine to caffeoyltyramine catalyzed by p-coumaroyltyramine 3-hydroxylase (CYP98A) appears to be specific to suberization and could serve as a marker for wound-inducible suberization. The expression of this enzyme could be used as a tool for future studies of suberin biosynthesis. Five potential candidate CYP98A genes from Solanum tuberosum EST databases were determined (designated pCT3Hl through pCT3H5). The pCT3H2 gene was sequenced, cloned into the pTrcHis2B expression vector and transformed into TOPlO E. coli. pCT3H2 expression was induced and the recombinant protein was tested for the catalytic conversion of p- coumaric acid, p-coumaroyltyramine, p-coumaroylshikimate, and p-coumaroylquinate using HPLC. …

Habitat Characteristics Correlated With The Settling Patterns Of Breeding Mallards And Canada Geese In The Mixed Woodland Plain Of Southern Ontario, David J. Messmer

Digitized Theses

Waterfowl produced on the mixed woodland plain (MWP) of southern Ontario contribute substantially to regional sport harvest and are economically important. I studied how habitat characteristics affected the distribution and abundance (settling patterns) of breeding mallards (Anas platyrhynchos) and Canada geese (Branta canadensis maxima) in the MWP. Additionally, I tested a hypothesis that Canada geese competitively exclude mallards from breeding habitat in the MWP. Aerial surveys, remote sensing, and geographic information systems (GIS) technology were used to assess these relationships at several spatial scales. Mallards had positive associations with the density of emergent, temporary open-water, and riverine wetlands and perennial …

Improved Algorithms For Alignment Between Rna Tertiary Structures, Qichan Ma

Digitized Theses

RNA is an important molecule which performs a wide range of functions in biological systems. The comparison between RNA secondary and tertiary structures has received much attention recently. It is a well known fact that structural features of RNAs are among the most significant factors in the molecular mechanisms involved in their functions. The presumption is that, to a preserved biological function there corresponds a preserved molecular structure. Therefore, the ability to compare RNA structures is useful. Furthermore, in many problems involving RNAs, it is required to have an alignment between RNA structures in addition to a similarity measure. Computing …

Promoter Analysis Of Potato (Solanum Tuberosum) Fatty Acid Ω- Hydroxylase (Faωhl), Daniel P. N. Lee

Digitized Theses

Suberin is a plant cell wall biopolymer that provides a protective barrier between its underground organs and the external environment and forms part of the wound healing response. With respect to the suberin associated poly-aliphatic domain (SPAD), the oxidation of oleic acid to produce ω-hydroxy-fatty acids is an important step to suberization, and can be used as a marker to study SPAD formation. In Solanum tuberosum one member of the CYP86A family [Fatty Acid ω-Hydroxylase 1 (FAωHl)] has been shown to have high levels of expression in suberizing root tissue. In the present study, a portion of the FAωHl promoter …

Maturational Changes And Effects Of Chronic Hypoxemia On Electrocortical Activity In The Ovine Fetus, Ashley Esther Keen

Digitized Theses

The development of electrocortical (ECoG) activity in humans and other mammals have been shown to be well-correlated with the neuroanatomical development of the brain, suggesting that ECoG activity may provide a functional role in brain development. Studies of ECoG state activity in utero, primarily in sheep, and of behavioural/sleep states in human newborns indicate that these states undergo maturational changes and are altered with hypoxic insults and adverse pregnancy conditions, such as fetal growth restriction. The purpose of the present study was firstly to design an automated computer analysis to comprehensively and objectively characterize ECoG activity, thereby providing a framework …

Plasticity In The Neuroendocrine Circuitry Responsible For Seasonal Breeding In The Ewe, Zamin Ladha

Digitized Theses

The neural circuitry underlying seasonal reproduction in sheep involves A15 dopamine neurons that undergo annual changes in synaptic inputs and dendritic complexity. Thyroidectomy (TH×) in late breeding season blocks both seasonal plasticity and the transition to anestrous.

To determine if neurotrophins regulate these morphological changes, we first examined the effects of TH× on the mRNA expression of neurotrophins, and their receptors, during the late breeding season. THX ewes had elevated TrkA expression in

the A15, and elevated NGF expression in the arcuate nucleus (ARC). The effects of TH× on seasonal alterations in glutamatergic inputs onto A15 neurons

were also examined. …

The Role Of Oxygen As A Regulator Of Nodal Expression In Poorly Metastatic Breast Cancer Cells, Meghan J. Taylor

Digitized Theses

Recently, the stem cell factor Nodal has been correlated with metastatic competence in breast cancer. We investigated hypoxia as a regulator of Nodal as it is an important feature of stem and cancer cell microenvironments. We hypothesized that hypoxia up-regulates Nodal in poorly metastatic T47D breast cancer cells through the Hypoxia-Inducible Factor-1 (HIF-1) and Notch signalling pathways. We exposed cells to decreasing concentrations of O2 for varying amounts of time. 0.5% O2 for 48 h experienced a maximal induction of Nodal mRNA expression and protein levels, which persisted for up to 72 h with reoxygenation. HIF-lα over-expression and knock down …

The Overwintering Physiology Of The Emerald Ash Borer, Agrilus Planipennis Fairmaire (Coleoptera: Buprestidae), Jill C. Crosthwaite

Digitized Theses

In order to understand potential for northward spread of the emerald ash borer in North America, the cold tolerance strategy and mechanisms involved in the cold tolerance of the emerald ash borer were investigated, and seasonal changes in these mechanisms monitored. Seasonal changes in energy stores were also measured. Emerald ash borers survive winter as freeze-intolerant prepupae. In winter, they have low supercooling points (~ 30 °C), which are achieved by accumulating high concentrations of glycerol (~4 M) in their body fluids and by the synthesis of antifreeze agents. Cuticular waxes help prevent inoculation from external ice. Triglyceride stores are …

The Role Of Antimicrobial Peptides In A Yeast-Beetle Association, Lulu Wang

Digitized Theses

Each species of Nitidulid beetle in the genus Conotelus is associated with a specific yeast species in the genus Metschnikowia. However, the reason for this selectivity is still unknown. Insects produce antimicrobial peptides (AMPs) that inhibit the growth of microorganisms. I hypothesized that Conotelus obscurus would produce specific AMPs that select in favor of its associated Metschnikowia species and that peptides produced by a particular Conotelus species can be induced by other yeast species. I investigated the antifungal activity of Conotelus obscurus larval extracts and compared their effect on three yeast species, Metschnikowia borealis, which is normally found in association …

Surface Modification By Fluorocarbon Plasma Deposition For Microscale Cellular Patterning, Amanda Marilyn Leclair

Digitized Theses

Cell micropatterning technology has made significant advances in recent years towards the miniaturization and organization of traditional cell culture systems. Surfaces are precisely engineered to present spatially controlled biological cues that direct cells into patterns. Large populations of living cells can therefore be probed under a variety of environments, and has inspired investigations in areas such as cell biology, cell-based biosensors, and tissue engineering. Herein, surface modification techniques were employed to chemically pattern transparent glass substrates and the biological response was assessed. The plasma deposition of a cell-inhibiting fluoropolymer material combined with photolithographic patterning generated a transparent substrate with cell …

Song As A Multi-Component Signal In Song Sparrows (Melospiza Melodia) As Measured Using An Acoustic Location System, Janet M. Lapierre

Digitized Theses

Birdsong is a complex, multi-component signal. The ‘multiple messages hypothesis’ proposes that each component conveys different information about male quality. If so, certain components may be preferentially advertised or provide different selective advantages. I examined three song components (complexity, sharing, and output) using an acoustic location system to record song sparrows (Melospiza melodia). First, I tested whether males preferentially advertise highly shared songs. I found no general pattern to overproduce such songs; however, older males preferentially sang highly shared dawn song before the onset of nesting. Additionally, daytime song contained more shared content when overall output was low. Second, I …

The Wrinkling Of Thin Elastic Sheets: Application To Cell Mechanics, Hamid Mohammadi

Digitized Theses

The wrinkling of thin sheets has been of great interest in various fields ranging from mechanics to biology. Despite significant progress in understanding the morphology and the dynamics of wrinkling patterns under static boundary conditions, little is known about how wrinkles behave when they are extremely driven. When in contact with an adhering particle, elastic sheets possess competing mechanically stable, wrinkled geometries if their thickness is below a critical value. In this thesis, molecular dynamics simulations are used to show that adhering particles moving laterally over a wrinkled elastic sheet induce instability transition of the wrinkles. These dynamics produce a …

Protein Structural Studies By Oxidative Labeling And Mass Spectrometry, Yalda Liaghati Mobarhan

Digitized Theses

Despite siginificant number of previous studies, the area of protein structure, folding and conformational dynamics remains a critical subject in biological chemistry. Oxidative labeling combined with electrospray ionization (ESI) mass spectrometry (MS) offers enormous opportunities for studying protein structures at the level of individual residues. Such high selectivity combined with excellent sensitivity makes ESI-MS a primary tool for the study of protein folding reactions. This approach is verified here by exploring the behavior of a model protein, myoglobin. Hydroxyl radicals (∙OH) are generated by laser

photolysis of H2O2 and react with the solvent exposed amino acids. In this way, information …

Reactive Oxygen Species Signaling In Extraembryonic Endoderm Differentiation, Jason W.H. Wen

Digitized Theses

Development of extraembryonic endoderm is essential for proper placenta formation and mammalian embryogenesis. Formation of primitive endoderm from cells of the inner cell mass is one of the earliest cell fate decisions made in the developing embryo. However, the signals and mechanisms involved in orchestrating this developmental process are not completely understood and are difficult to study in vivo. The mouse embryonic carcinoma (F9) cell line can be chemically re-programmed to mimic cells of the inner cell mass, thereby serving as an in vitro model to study extraembryonic endoderm differentiation. F9 cells treated with retinoic acid (RA) differentiate into primitive …

Synthesis And Characterization Of Ph Sensitive Hydrogel Based Nanocarriers For The Controlled Release Of Protein Drugs, Kazi Farida Akhter

Digitized Theses

Controlled drug delivery technology represents one of the frontier areas of science, which involves a multidisciplinary scientific approach and contributes to human health care. Hydrogel based nanoparticles (NPs) have gained considerable attention in recent years as one of the most promising nanoparticulate drug delivery systems, owing to their unique potentials by combining the characteristics of a hydrogel system, i.e. hydrophilicity and extremely high water content, with a nanoparticle i.e. very small size. In this research, hydrogel-based nanoparticles, i.e. gelatin NPs, were used as a carrier to encapsulate protein drug for controlled release in a prolonged manner. Bovine serum albumin (BSA) …

Secretion And Activity Of A Novel Cysteine-Rich Protein From Helicobacter Pylori, Hcpe, Sari Kichler

Digitized Theses

HcpE (HP0235) is a cysteine-rich protein that is specific to and highly conserved in Helicobacters. HcpE elicits strong antibody production in patients infected with H. pylori. We demonstrated that HcpE is secreted by H. pylori. Structural modeling demonstrated that HcpE is a solenoid protein that requires the formation of many disulphide bonds prior to secretion. Moreover, the presence of Sell-like repeat (SLR) motifs implies that protein-protein interactions are necessary for function of HcpE. Two experimental approaches were implemented to identify interacting partners for HcpE. Using mature folded HcpE, an interaction with HPOl 84, a protein of unknown function was identified. …

Proteomic Analysis Of Redox Sensitive Proteins In A Huntington’S Disease Cell Model, Andrea L. Pitts

Digitized Theses

No abstract provided.

The Impact Of Material Factors On Female Juvenile Delinquency Trends, Anne Marie Price

All-Inclusive List of Electronic Theses and Dissertations

This study examined the difference between female juvenile delinquents and nondelinquents in relationship to a combination of maternal factors (negative maternal behaviors, occupational stress, perceived social support, and maternal parenting stress). Participants were 128 biological mothers of daughters between the ages of 12 and 18 who were either mothers of clients or were clients themselves of a Midwest community health center in one of several clinics in Martinsville, Mooresville, Bedford, Bloomington, and Spencer, Indiana. Participants completed six questionnaires, including: the Demographics Questionnaire, the Maternal Behavior Index, the Adolescent Behavior Survey, the Occupational Crisis Survey, the Duke Social Support Inventory, and …