Life Sciences Commons^™

The Intracellular Behaviour Of Burkholderia Cenocepacia In Murine Macrophages, Jennifer S. Tolman

Electronic Thesis and Dissertation Repository

Burkholderia cenocepacia is an opportunistic pathogen causing life-threatening infections in cystic fibrosis and other immunocompromised patients. The bacterium survives within macrophages by interfering with typical endocytic trafficking, resulting in delayed maturation of a B. cenocepacia-containing phagosome. We hypothesize that B. cenocepacia alters gene expression after internalization by macrophages, inducing genes involved in intracellular survival and host adaptation. Furthermore, we hypothesize that specialized bacterial secretion systems are involved in the interactions between intracellular bacteria and macrophages. In this work, we characterize later-stage infection of macrophages by B. cenocepacia, showing replication within an acidified endosomal compartment suggestive of a phagolysosome. …

Brassinosteroid-Mediated Stress Tolerance In Arabidopsis Thaliana, Tawhidur Rahman

Electronic Thesis and Dissertation Repository

Brassinosteroids (BRs) are a group of steroidal plant hormones that are essential for proper plant development and also promote stress tolerance. Without BRs, plants are dwarfs and infertile. To understand the molecular mechanisms underlying BR-mediated stress tolerance, global gene expression analysis of untreated and 24-epibrassinolide (EBR)-treated Arabidopsis thaliana seedlings under non-stress and heat stress (HS) conditions was carried out. Microarray data analysis indicated that stress-related genes were predominant within the EBR up-regulated gene data set. Furthermore, several of these genes were abscisic acid (ABA) and jasmonic acid (JA) related. Measurements of endogenous hormones showed significant increases in the levels ABA …

Dha Supplemented In Peptamen Diet Offers No Advantage In Pathways To Amyloidosis: Is It Time To Evaluate Composite Lipid Diet?, Zareen Amtul, Mary Keet, Peter Merrifield, David Westaway, Richard F. Rozmahel

Anatomy and Cell Biology Publications

Numerous reports have documented the beneficial effects of dietary docosahexaenoic acid (DHA) on beta-amyloid production and Alzheimer's disease (AD). However, none of these studies have examined and compared DHA, in combination with other dietary nutrients, for its effects on plaque pathogenesis. Potential interactions of DHA with other dietary nutrients and fatty acids are conventionally ignored. Here we investigated DHA with two dietary regimes; peptamen (pep+DHA) and low fat diet (low fat+DHA). Peptamen base liquid diet is a standard sole-source nutrition for patients with gastrointestinal dysfunction. Here we demonstrate that a robust AD transgenic mouse model shows an increased tendency to …

Habituation And Prepulse Inhibition Of The Acoustic Startle In Rodents, Bridget Valsamis, Susanne Schmid

Anatomy and Cell Biology Publications

The acoustic startle response is a protective response, elicited by a sudden and intense acoustic stimulus. Facial and skeletal muscles are activated within a few milliseconds, leading to a whole body flinch in rodents. Although startle responses are reflexive responses that can be reliably elicited, they are not stereotypic. They can be modulated by emotions such as fear (fear potentiated startle) and joy (joy attenuated startle), by non-associative learning processes such as habituation and sensitization, and by other sensory stimuli through sensory gating processes (prepulse inhibition), turning startle responses into an excellent tool for assessing emotions, learning, and sensory gating. …

Metastatic Disease: Interactions Between Tumor Cells And Host Environment During Cancer Cell Spread, Jennifer M. Maclean

Electronic Thesis and Dissertation Repository

Tumor and metastasis formation are not cell autonomous phenomena, but rather an evolution of disease within and responding to the host environment. Metastatic spread from a primary tumor occurs as a result of a complex interplay between tumor cells and the host, wherein tumor cells must escape the primary tumor, enter the host vasculature, travel to and arrest in a distant tissue and survive and grow in that new organ. It is known that cells that progress through these stages must both escape and exploit host systems, yet the mechanisms used are not fully understood. Therefore, the goal of this …

The Regulation Of Cell Division And Neurogenesis By The Chromatin Remodeling Protein Atrx, Kieran L. Ritchie

Electronic Thesis and Dissertation Repository

Mutations in the ATRX gene cause alpha thalassemia mental retardation X-linked syndrome (ATR-X). Individuals with ATR-X syndrome show a broad range of developmental abnormalities including severe cognitive, behavioural, and learning deficits, seizures, and microcephaly, indicating that ATRX is essential for normal development of the central nervous system. Conditional inactivation of Atrx in the developing mouse forebrain leads to a reduction in cerebral cortical size, elevated levels of p53-dependent neuronal apoptosis, and dysgenesis of certain subcortical structures, including the hippocampus and dentate gyrus, confirming a requirement for Atrx in mammalian brain development. The mammalian ATRX gene encodes a member of the …

The Effects Of Superovulation And Embryo Culture On Genomic Imprinting In A Mouse Model System, Brenna A. M. Velker

Electronic Thesis and Dissertation Repository

Genomic imprinting is a specialized transcriptional mechanism resulting in the unequal expression of alleles based on their parent-of-origin. Imprinted genes are critical for embryonic and fetal development and their dysregulation is linked to a group of human diseases called imprinting disorders, including Beckwith-Wiedemann Syndrome, Angelman Syndrome and Silver-Russell Syndrome. Two critical phases of genomic imprinting exist. The acquisition phase occurs in developing germ cells, asynchronously for different imprinted loci, while the maintenance phase takes place during preimplantation development, while the rest of the genome is undergoing demethylation. Increased frequencies of human imprinting disorders are observed in children following the use …

Imaging Mass Spectrometry Detection Of Gangliosides Species Within The Mouse Brain Following Transient Focal Cerebral Ischemia, Shawn N. Whitehead, Kenneth H. N. Chan, Sandhya Gangaraju, Jacqueline Slinn, Jianjun Li, Sheng T. Hou

Anatomy and Cell Biology Publications

Gangliosides, a member of the glycosphingolipid family, are heterogeneously expressed in biological membranes and are particularly enriched within the central nervous system. Gangliosides consist of mono- or poly-sialylated oligosaccharide chains of variable lengths attached to a ceramide unit and are found to be intimately involved in brain disease development. The purpose of this study is to examine the spatial profile of ganglioside species using matrix-assisted laser desorption/ionization (MALDI) imaging (IMS) following middle cerebral artery occlusion (MCAO) reperfusion injury in the mouse. IMS is a powerful method to not only discriminate gangliosides by their oligosaccharide components, but also by their carbon …

Use Of Imaging Biomarkers To Assess Perfusion And Glucose Metabolism In The Skeletal Muscle Of Dystrophic Mice, Nabeel Ahmad, Ian Welch, Robert Grange, Jennifer Hadway, Savita Dhanvantari, David Hill, Ting-Yim Lee, Lisa M Hoffman

Robarts Imaging Publications

BACKGROUND: Duchenne muscular dystrophy (DMD) is a severe neuromuscular disease that affects 1 in 3500 boys. The disease is characterized by progressive muscle degeneration that results from mutations in or loss of the cytoskeletal protein, dystrophin, from the glycoprotein membrane complex, thus increasing the susceptibility of contractile muscle to injury. To date, disease progression is typically assessed using invasive techniques such as muscle biopsies, and while there are recent reports of the use of magnetic resonance, ultrasound and optical imaging technologies to address the issue of disease progression and monitoring therapeutic intervention in dystrophic mice, our study aims to validate …

Vacht Knock-Down Mice Show Normal Prepulse Inhibition But Disrupted Long-Term Habituation, S. Schmid, E. Azzopardi, X. De Jaeger, Marco Prado, V. F. Prado

Anatomy and Cell Biology Publications

The neurotransmitter acetylcholine (ACh) plays a crucial role in both the central and peripheral nervous system. Central cholinergic transmission is important for cognitive functions and cholinergic disruptions have been associated with different neural disorders. We here tested the role of cholinergic transmission in basic cognitive functions, i.e. in prepulse inhibition (PPI) and short-term habituation (STH) as well as long-term habituation (LTH) of startle using mice with a 65% knockdown (KD) of the vesicular ACh transporter (VAChT). These mice are slow in refilling cholinergic synaptic transmitter vesicles, leading to a reduced cholinergic tone. Prepulse inhibition has been assumed to be mediated …

Regional Specification Of The Xenopus Lateral Plate Mesoderm, Steven J. Deimling

Electronic Thesis and Dissertation Repository

@font-face { font-family: "Times"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }

Successful patterning of the embryo, from establishing the three primary axes to the regional specification of tissue progenitors is essential to generating a viable embryo. The three germ layers in the early embryo undergo patterning through slightly different mechanisms. The tissue of interest to this study is the lateral plate mesoderm (LPM), which will give rise to the lineages of the cardiovascular system and is essential for regional specification of adjacent germ layers. …

Ocular Pathology Relevant To Glaucoma In A Gja1(Jrt) Mouse Model Of Human Oculodentodigital Dysplasia, Edmund Tsui, Kathleen A. Hill, Alex M. Laliberte, Daniel Paluzzi, Ilia Kisilevksy, Qing Shao, Godfrey J. Heathcote, Dale W. Laird, Gerald M. Kidder, Cindy M. L. Hutnik

Anatomy and Cell Biology Publications

PURPOSE. Oculodentodigital dysplasia (ODDD) is a human disorder caused by mutations in the gap junction alpha 1 (GJA1) gene encoding the connexin43 (Cx43) gap junction protein. Causal links between GJA1 mutations and glaucoma are not understood. The purpose in this study was to examine the ocular phenotype for Gja1(Jrt/+) mice harboring a Cx43 G60S mutation. METHODS. In young Gja1(Jrt/+) mice, Cx43 abundance was assessed with a Western blot, and Cx43 localization was visualized using immunohistochemistry and confocal microscopy. Intraocular pressure (IOP) was measured by rebound tonometry, and eye anatomy was imaged using ocular coherence tomography (OCT). Hematoxylin and eosin (H&E)-stained …

Novel Strains Of Mice Deficient For The Vesicular Acetylcholine Transporter: Insights On Transcriptional Regulation And Control Of Locomotor Behavior, Christina Martins-Silva, Xavier De Jaeger, Monica S. Guzman, Ricardo D. F. Lima, Magda S. Santos, Christopher Kushmerick, Marcus V. Gomez, Marc G. Caron, Marco A. M. Prado, Vania F. Prado

Anatomy and Cell Biology Publications

Defining the contribution of acetylcholine to specific behaviors has been challenging, mainly because of the difficulty in generating suitable animal models of cholinergic dysfunction. We have recently shown that, by targeting the vesicular acetylcholine transporter (VAChT) gene, it is possible to generate genetically modified mice with cholinergic deficiency. Here we describe novel VAChT mutant lines. VAChT gene is embedded within the first intron of the choline acetyltransferase (ChAT) gene, which provides a unique arrangement and regulation for these two genes. We generated a VAChT allele that is flanked by loxP sequences and carries the resistance cassette placed in a ChAT …

The Life Cycle Of Pannexins: Trafficking, Cell Surface Dynamics, Turnover And Degradation, Ruchi Gehi

Electronic Thesis and Dissertation Repository

Pannexins (Panxs) are a recently identified family of channel-forming glycoproteins, comprised of three members: Panx1, Panx2 and Panx3. Panxs were classified as gap junction (GJ) proteins based on their shared sequence homology to the invertebrate GJ protein, innexins. While no sequence homology exist between Panxs and the GJ proteins, connexins (Cxs), they share similar topology with four transmembrane domains, two extracellular loops, an intracellular loop and cytoplasmic exposed amino and carboxy terminal tails. In this study, we investigated if Panx1 and Panx3 exhibit unique or shared properties of cell surface delivery, mobility, cytoskeletal dependency, internalization and degradation, to the well …