Biology Commons^™

Neuroinflammation In Alzheimer’S Disease Mouse Brain Following Repetitive Mild Traumatic Brain Injury, Lujain Almuhanna

Electronic Theses and Dissertations

Traumatic brain injuries (TBIs) are a common form of head injury, with mild TBIs (mTBIs) making up 75-90% of the TBI severity scale. It’s been suggested that repetitive mild TBIs (rmTBIs) may enhance effects of Alzheimer’s Disease (AD). With dementia linking TBI and AD together, we investigated the memory hub of the brain - the hippocampus. Astrocytes and microglia are two glial cells that respond to neuroinflammation and therefore imaged in hippocampal regions of the 3xTg-AD mouse brain. We hypothesized that AD brain pathology (i.e., neuroinflammation) would be accelerated in 3xTg-AD mice following rmTBIs early in life. Analyses revealed that …

Mechanisms Behind The Chaperone Activity Of Nucleic Acids, Theodore J. Litberg

Electronic Theses and Dissertations

Understanding the interplay between nucleic acids and protein aggregation is integral to the understanding of proteostasis, aging, and neurodegenerative disease progression. Nucleic acids are known to modulate the aggregation of PrP, tau, ⍺-synuclein, and other disease relevant proteins. Although the interactions between misfolded protein and nucleic acids can play a role in disease, this interaction may potentially be beneficial as well. Our group and others have shown nucleic acids can be powerful chaperones. Previous work has shown both RNA and DNA can prevent protein aggregation and RNA can pass off protein clients to the heat shock protein (Hsp) system. Here …

The Role Of Ehd2 In Endothelial Cells, Rachael Judson

Electronic Theses and Dissertations

The role of EHD2 in terms of Cav1 interaction had not been previously characterized and was the main goal of this research. Cav1 has been shown to lead to the ubiquitination of Rac1. Because of this, the role of EHD2 in Rac1 regulation was investigated. An increase in long-term migration in endothelial cells was observed and suggested that EHD2 impacts the RhoA pathway instead of the Rac1 pathway. This lead to the hypothesis that EHD2 controls a part of the RhoA pathway. This hypothesis is supported by the loss of filamentous actin and an increase in serrated junctions in cells …

Environmental Gradients Impact Key Leaf Traits In Riparian Trees, Amanda Malone

Electronic Theses and Dissertations

Specific leaf area (SLA) reflects a plant’s carbon investment per area and relates to generalized leaf economics spectrum growth strategies (LES). To fill gaps of knowledge about intraspecific SLA variation and why it is often inconsistent with the LES, we studied the response of two riparian tree species along the urban-rural gradient in Northeastern Colorado: an invasive, nitrogen-fixer with broad tolerances and a nitrogen-limited and shade-intolerant native. Despite these differences, the two species responded similarly, apart from the response to the urban-rural gradient, in which lower nitrogen in rural areas was associated with a more conservative strategy in the native …

Optimized Microbial Recombinant Production Of Hiv-1 Anti-Envelope Antibody Fragments With Applications To Single Particle Tracking Of Virus Assembly, Merissa Michelle Bruns

Electronic Theses and Dissertations

In my findings, I have established a set series of protocols to recombinantly produce, purify and apply various fluorescent probes in vitro for the fluorescent labeling and study of the human immunodeficiency virus type 1 (HIV-1) envelope (Env) protein during HIV viral assembly. There remains insufficient knowledge about the molecular dynamics and interactions of HIV-1 Env protein with its counterpart, Gag, on the inner host cell surface during assembly of a mature virus particle. There also remains an insufficient amount of data for the understanding and clarification of the mechanism of action of a known host cell HIV-1 restriction factor, …

Notch Regulates Vascular Collagen Iv Basement Membrane Through Modulation Of Lysyl Hydroxylase 3 Trafficking, Stephen J.B. Gross

Electronic Theses and Dissertations

Collagen type IV (Col IV) is a basement membrane protein associated with early blood vessel morphogenesis and is essential for blood vessel stability. Defects in vascular Col IV deposition are the basis of heritable disorders, such as small vessel disease, marked by cerebral hemorrhage and drastically shorten lifespan. To date, little is known about how endothelial cells regulate the intracellular transport and selective secretion of Col IV in response to angiogenic cues, leaving a void in our understanding of this process. Our aim was to identify trafficking pathways that regulate Col IV deposition during angiogenic blood vessel development. We have …

Understanding Patterns And Functional Impacts Of An Invasive Tree And Its Biological Control In A Riparian System, Annie L. Henry

Electronic Theses and Dissertations

Invasive species have become an inextricable part of the landscape, particularly in riparian plant communities, and removal is often a key component of restoration programs. Biological control (biocontrol) is a method of removal that is often both efficient and effective. However, the impact of biocontrol on target species and indirect effects from invasive species removal can be hard to predict. While monitoring the impact of invasive species removal usually involves some species-based assessment such as changes in diversity, historically dominant species or native species, these strategies do not typically provide insight into the mechanisms underlying plant community response to removal. …

Development Of Endoplasmic Reticulum Targeted Probes And Red Fluorescent Probes For Detecting Zinc, Drew Maslar

Electronic Theses and Dissertations

Zinc (Zn²⁺) is the second most abundant transition metal in the body and is important in various biological functions. Fluorescent sensors based on circularly permuted fluorescent proteins (cpFPs) have been previously made to detect labile, or unbound, Zn²⁺ within the cytoplasm of cells. These sensors have proven invaluable for studying Zn²⁺, however, these sensors are limited to their use in the cytoplasm and by the fact that only green cpFP have been utilized to create fluorescent Zn²⁺ sensors. In this thesis, we use a combination of peptide targeting sequences, site-directed mutagenesis, and rational design …

Cellular And Organismal Ramifications Of De Novo Purine Synthesis Dysregulation, Randall Craig Mazzarino

Electronic Theses and Dissertations

Purines are a class of nitrogenous bases and are essential small molecules to life. Purines are used within the cell as genetic information carriers, energy currency, signaling molecules, and cofactors for multiple processes. They are formed through de novo and salvage pathways found in cells across the phylogenetic tree. The substrates of enzymes within de novo purine synthesis are known to influence other processes within the cell, such as energy homeostasis. In humans, de novo purine synthesis disorders are rare, with around 100 people identified. These patients exhibit a range of phenotypes, with varying degrees of mental retardation, seizure activity, …

Actin Regulation And Furrow Dynamics During Early Drosophila Embryogenesis, Yi Xie

Electronic Theses and Dissertations

Drosophila embryogenesis starts with a single nucleus undergo 13 rounds of nuclear divisions called syncytial cycles. Staring at cycle 10 when nuclei migrate to the surface of the embryo, massive and dynamic cortical actin structures and cleavage furrow formations occur. How actin regulators coordinate into an organized network directing three-dimension actin structures in the developing organisms is an unsolved question. Here, I present an in-depth characterization of actin cap dynamics: the actin caps go through expansion, stabilization, elongation and fragmentation phases in each cycle. Arp2/3 is the major contributor to actin cap formation. The functions of 7 different actin and …

Characterization Of Vps41 And Its Role In The Regulated Secretory Pathway, Christian Henry Burns

Electronic Theses and Dissertations

Insulin secretory granules (SGs) mediate the regulated secretion of insulin, which is essential for glucose homeostasis. The basic machinery responsible for this regulated exocytosis consists of specific membrane proteins present both at the plasma membrane and on insulin SGs. The protein composition of insulin SGs thus dictates their release properties, yet the mechanisms controlling insulin SG formation, which determines this molecular composition, remain poorly understood. VPS41, a component of the endolysosomal tethering HOPS complex, was recently identified as a cytosolic factor involved in the formation of neuroendocrine/neuronal granules. We now find that a stable pool of VPS41 exists outside of …

Qualitative And Quantitative Fitness Consequences Of Advanced Maternal Age, Claudia Jean Hallagan

Electronic Theses and Dissertations

Parental age can affect offspring fitness across taxa and through various mechanisms. However, the effect(s) of advanced maternal age on offspring, particularly in insects, has not been comprehensively reviewed making it difficult to draw conclusions about the effects of advanced maternal age on offspring in insects. In my first chapter, I reviewed maternal age literature and found overall negative effects of advanced maternal age on offspring fitness. However, results vary depending on which fitness measures were used, the life stages at which offspring were measured, and the experimental design of the study. In my second chapter, I conducted an experiment …

Spg Directs Arp2/3 Mediated F-Actin Networks To Support Syncytial Furrow Ingression In Drosophila, Shannon M. Henry

Electronic Theses and Dissertations

In the Drosophila embryo, nuclear divisions 10-13 occur in a syncytium with transient membrane furrows separating neighboring nuclei before the occurrence of cellularization. This process is driven by cytoskeletal and membrane trafficking networks, and while RalA and Rab8 have been identified to drive membrane addition to furrows, less is known about the control of dynamic F-actin networks needed for furrow formation. Here, the role of the DOCK protein Sponge (Spg) in furrow formation is explored through shRNA knockdown and live-imaging of syncytial Drosophila embryos. I have found that Spg is required for furrow ingression and that without Spg, furrows can …

The Ecology Of Land Managers In Riparian Restoration, Lisa Buie Clark

Electronic Theses and Dissertations

While previous studies in restoration ecology have focused on the efficacy of direct management actions, the driving forces on management decisions (e.g., managers' characteristics or attitudes, environmental conditions) and the indirect impacts on restoration outcomes from management decisions (such as whether to collaborate) are quantified here for the first time. As a case study, I used data from 244 sites across the riparian Southwest US where the invasive shrubby tree Tamarix sp. was removed using various different methods. I surveyed and interviewed the 45 land managers who were responsible for the removal projects to determine their characteristics, attitudes, and …

Small Rho Gtpase Family Member Cdc42 And Its Role In Neuronal Survival And Apoptosis, Noelle Christine Punessen

Electronic Theses and Dissertations

Neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Alzheimer's and Parkinson's disease are caused by a progressive and aberrant destruction of neurons in the brain and spinal cord. These disorders lack effective long term treatments, and existing options focus primarily on either delaying disease onset or alleviating symptomology. Dysregulated programmed cell death, known as apoptosis, is one of the most significant contributors to neurodegeneration, and is controlled by a number of different factors. Rho GTPases are a protein class with recognized importance in proper neuronal development and migration, and have more recently emerged as regulators of apoptosis and neuronal survival. …

Ex-Vivo Slaughterhouse Porcine Crystalloid-Perfused Beating Heart Via Langendorff Method, Rahiemin Talukder

Electronic Theses and Dissertations

The objective of this study was to resuscitate isolated beating porcine hearts obtained from slaughterhouse swine for a minimum of 1 hour with a crystalloid buffer reperfusion instead of blood via an extracorporeal Langendorff apparatus. The isolated beating heart functions outside of the body under simulated physiologic conditions. Live functional anatomy was controlled under benchtop experimental settings. Porcine hearts (26 total) were topically cooled with saline. 300mL of 25°C cardioplegia with 20KU Streptokinase was preflushed via aortic root. WIT was less than 5 minutes. 1L 4°C cardioplegia was flushed antegrade with aortic cannula (Group 1) or coronary catheterization (Group 2). …

Metabolomics Of Mammalian And Cellular Models Of Aging, Nathan Gonzales Duval

Electronic Theses and Dissertations

Aging is often associated with impaired cognition and a progressive loss of organ function over time accompanied by an increased susceptibility for many disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), heart disease, osteoporosis, type II diabetes, and many forms of cancer. With a rapidly aging population, the negative impacts of aging and age-related disorders is a major cause of increased human suffering both for affected individuals and for families and caregivers. Metabolic changes are also apparent in normal aging, but may increase in magnitude or nature with accompanying disease states or with accelerated aging. Thus, studying aging in a …

Akap150 Dynamics In Anterior Pituitary Cells, Kristen E. Dew

Electronic Theses and Dissertations

Cellular communication occurs as a result of changes in signaling pathways. A well-studied signaling pathway is through G protein coupled receptors (GPCRs). In gonadotropes, GPCR stimulation by GnRH leads to the activation of protein kinase A (PKA). Activated PKA can phosphorylate ion channels, potentially causing an influx of calcium, depolarization and secretion of hormones. A scaffolding protein known as AKAP150 anchors PKA near L-type calcium channels. In addition, AKAP150 anchors phosphatases, which provides temporal control during signaling events. It was recently shown that AKAP150 is mobile in neuronal dendrites, providing regulation to where the signaling cascade occurs in the cell. …

Neuroprotection Comparison Of Different Nutraceutical Compounds Against Mechanistically Distinct Cell Death Inducing Agents, Faten I. Taram

Electronic Theses and Dissertations

Neurodegenerative diseases like Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), include the progressive loss of structure and function of neurons leading to neuronal death. All of these diseases are fatal, as there is no cure for them. The causes of these diseases are unknown; however, there are many proposed mechanisms that lead to neurodegenerative diseases. Oxidative stress is the leading cause of cell death in neurodegenerative diseases, in addition to other mechanisms including endoplasmic reticulum stress, proteasome inhibition, nitrosative stress, inflammation and excitotoxicity. More understanding of the death mechanisms at work in neurodegeneration is necessary to …

The Role Of P38 Mapk In Protein Homeostasis And Aging, Sarah Mae Ryan

Electronic Theses and Dissertations

Aging is characterized by a failure to maintain proper protein homeostasis, potentially leading to tissue dysfunction. Though a variety of genes have been found to regulate lifespan and age-related behaviors how these genetic factors contribute to protein homeostasis has not been fully explored. Here, we report that the evolutionarily conserved aging gene p38 MAPK (p38Kb) regulates age-dependent protein homeostasis. Over-expression of p38Kb results in reduced protein aggregation, while knockout of p38Kb leads to increased protein aggregation. Furthermore, we find that p38Kb regulates protein homeostasis, lifespan, and age-dependent locomotor functions through an interaction with the Chaperone Assisted Selective Autophagy complex; a …

Regulation Of Synaptogenesis By The Mirna Pathway And Fmr/P Bodies, Jacqueline Rochelle Furlong

Electronic Theses and Dissertations

Post-transcriptional regulation of mRNA is facilitated by different mechanisms, such as microRNA (miRNA) induced gene silencing or fragile X mental retardation protein (FMRP) mediated repression either independent of or acting through cytoplasmic RNA Processing bodies (P bodies). DPTP99A, Lar, and Wg have known functions during synaptogenesis and may be targets of miR-8. Here, we provide evidence that miR-8 regulates DPTP99A in vitro. Non-endogenous miR-8 expressed using an UAS driver regulates Lar. Endogenous miR-8 may regulate DPTP99A in vivo. Here we show that FMRP is capable of colocalizing with the P body components: DCP1, HPat, and Me31B, but not …

Gene Expression In The Choanoderm, Jesús Federico Peña

Electronic Theses and Dissertations

The body plan of sponges (phylum Porifera) is an outlier among modern animals and is thought to have special evolutionary significance. Sponges lack muscles, nerves and a gut. Instead, they are composed of few cell types and simple tissues that function to pump water through an internal canal network where bacterial prey are filtered by a specialized tissue called the choanoderm. The choanoderm is composed of cells with striking similarity to choanoflagellates, the unicellular relatives of animals. Thus, the traditional view is that the sponge choanoderm is a useful model of the first animal epithelial tissues. Using the freshwater sponge …

Development And Testing Of A Rapid Multiplex Assay For The Identification Of Biological Stains, Kevin M. Legg

Electronic Theses and Dissertations

While DNA profiling makes it possible to individualize biological stains, the identification of the stain itself can present forensic serologists with a significant challenge. Current antibody- and enzyme activity-based assays used by forensic practitioners for biological stain identification yield only presumptive results. Positive results with non-target body fluids or cross-reactivity with non-human sources has also been well documented. Some tests can consume unacceptable quantities of precious evidence while for some body fluids (vaginal fluid and menstrual blood) there are simply no available tests at all.

This research presented here aims to develop and rigorously test a fast, accurate, and sensitive …

Post-Transcriptional Shaping Of Neurons: The Role Of Mirnas And Fmrp-Interacting P-Body Components In Regulating Neuronal Structure, Breanna Symmes

Electronic Theses and Dissertations

Changes in synaptic structure in response to neuronal stimulation are believed to underlie the processes of learning and long-term memory. However, the mechanisms for these structural modifications are poorly understood. It is well-known that activity-dependent synaptic modifications rely upon new protein synthesis, and rapid new protein synthesis, at that. Therefore, it is widely believed that pools of messenger RNAs held in a state of translational repression are transcribed in a neuronal cell body prior to stimulation, and transported to the synapse, where they reside until stimulation occurs.

This study investigates the roles and interactions of translational repression mechanisms to better …

Activity-Regulated Micrornas: Modulators Of Synaptic Growth At The Drosophila Neuromuscular Junction, Katherine Ruth Nesler

Electronic Theses and Dissertations

It is well established that long-term changes in synaptic structure and function are mediated by rapid activity-dependent gene transcription and new protein synthesis. A growing body of evidence supports the involvement of the microRNA (miRNA) pathway in these processes. We have used the Drosophila neuromuscular junction (NMJ) as a model synapse to characterize activity-regulated miRNAs and their important mRNA targets. Here, we have identified five neuronal miRNAs (miRs-1, -8, -289, -314, and -958) that are significantly downregulated in response to neuronal activity. Furthermore we have discovered that neuronal misexpression of three of these miRNAs (miR-8, -289, and -958) is capable …

Rala And Rab8 Regulate Drosophila Embryogenesis, Zhongyuan Zuo

Electronic Theses and Dissertations

Pseudocleavage furrow dynamics initiate at cycle 10 to help with mitotic divisions that lack cytokinesis. Permanent furrows then form at the beginning of cellularization (cycle 14). Cytoskeletal networks such as F-actin and non-muscle Myosin II have been demonstrated to be required for furrow formation and provide anchor points for chromosomal segregation. However, what drives the onset of furrow formation and membrane addition remains largely unclear. In my thesis, I have explored RalA and Rab8 function during furrow formation at metaphase and cellularization stages. These furrows are critical for correct chromosomal segregation, while disruption of furrow formation results in severe developmental …

Role Of Camkii In Pancreatic Alpha Cells, Brooke A. Buckland

Electronic Theses and Dissertations

Calcium/calmodulin-dependent protein kinase II (CaMKII) has been identified as an important modulator in controlling electrical activity in neurons and the heart; however, a role for CaMKII in pancreatic alpha cell signaling has not been previously reported. Upon activation by calcium/calmodulin, CaMKII phosphorylates proteins involved in intracellular calcium homeostasis by inducing downstream effects such as an increase in AMPA-receptor single channel conductance, potentiation of L-type voltage dependent calcium channels, and enhanced surface expression of inhibitory GABA_A-receptors. In the pancreas, an increase in intracellular calcium drives secretion of glucagon from alpha cells within the Islets of Langerhans. α-cells contain many …

Vegetation Response After Invasive Tamarix Spp. Removal In The Riparian Zone And Semi-Arid Rangeland Ecosystems, Hisham Nagi El Waer

Electronic Theses and Dissertations

Removal of Tamarix spp. (a.k.a. tamarisk, saltcedar, Athel) invasion is often involved in restoration of Western, riparian habitat; however monitoring of vegetation after removal is often neglected and thus opportunity for adaptive management lost. To address this need, I have conducted three and half years of monitoring vegetation response after invasive Tamarix removal in twenty-five sites on the East and Western Colorado, starting fall 2009. I am also comparing six different methodologies: Point intercept, line transect, nearest neighbor, meter-square quadrats, nested Whittaker plots, and densitometer with the objective of developing monitoring protocols that can be used by …

Evolution Of Xenopus Tropicalis Mc2r: Expression And Activation, Perry Victoria Davis

Electronic Theses and Dissertations

The structure and functional relationship between the melanocortin-2 receptor (MC2R) and adrenocorticotropic hormone (ACTH) is the most complex of the melanocortin gene family. Prior studies had been done on amniote tetrapod MC2Rs (e.g., mammals); this study analyzed the expression and activation of MC2R by an anamniote tetrapod, Xenopus tropicalis (xtMC2R). An immunofluorescence approach, done on the expression of xtMC2R in Chinese Hamster Ovary cells (CHO cells), indicated that the trafficking of xtMC2R to the plasma membrane required co-expression with a tetrapod MRAP1(melanocortin-1 receptor accessory protein). A cAMP-reporter assay was used to show that xtMC2R can activated by human ACTH(1-24, but …

Mitochondrial Glutathione Transport: Implications For Bcl-2 And Neuronal Survival, Heather Marie Wilkins

Electronic Theses and Dissertations

Oxidative stress is a contributing factor to many neurodegenerative diseases. In particular, mitochondria are a key source of oxidative stress due to electron leakage at the level of the electron transport chain. To combat the endogenous production of reactive oxygen and reactive nitrogen species mitochondria are equipped with several redox-cycling systems, such as glutathione (GSH). Mitochondrial GSH has been shown to be a critical reservoir of this antioxidant, where selective depletion of mitochondrial GSH can induce apoptosis in several systems. Many studies have intricately linked Bcl-2 to cellular GSH status and it has been previously shown that Bcl-2 is a …