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Thermal Ecology Of Urosaurus Ornatus (Ornate Tree Lizard), In The Northern Chihuahuan Desert On Indio Mountains Research Station, Texas, Julia Sandoval Alva

Open Access Theses & Dissertations

The main goal of this study was to determine the thermal ecology of the small tree lizard Urosaurus ornatus in a Chihuahuan Desert landscape. The study site was located at Indio Mountains Research Station (IMRS), Hudspeth County, Texas. We obtained body temperature (Tb) data on 385 lizards collected from April 2007 to June 2014 during the active period using a cloacal thermometer. Additionally, we recorded air temperature (Ta) and substrate temperature (Ts) of lizard microhabitats at the time of capture, and the operative temperature of lizard models left in the sun and shade from May to September 2014. My results …

Biochemical Characterization Of Four Distinct Proteins, Gustavo A. Avila

Open Access Theses & Dissertations

Proteins are ubiquitous in all living organisms, executing the majority of cellular functions in distinct ways. Understanding a protein's role necessitates investigating its structure and function, which are closely related. My research couples these two aspects by delving into the biochemical and structural characterization of proteins in four distinct systems, all playing central roles in numerous significant disease progressions. These four original research endeavors were all targeted for structural studies with a unifying relationship to establish our new structural biochemistry lab. These four systems are: (1) Gam1, an early adenovirus protein globally inhibiting host SUMOylation; (2) Anthrax toxin complexed with …

The Sumoylation Of The Non-Structural Protein 1 Of The Influenza A Virus Plays A Dual Role During Viral Infection, Jason Michael Chacon

Open Access Theses & Dissertations

The potential for a highly pathogenic influenza pandemic remains a concern for global health. The ability of the influenza virus to undergo antigenic shift and genetic drift give circulating strains of influenza the high probability of developing resistance to current antiviral therapies. Emerging strains of higher virulence, to which the infected person has not had any previous exposure to viral antigens, pose a greater threat of serious illness and death. Currently, there is no antiviral therapy that is effective against all strains of influenza, emphasizing the need to develop new strategies that target cellular systems required for viral replication to …

Furthering Our Understanding And Assessing The Effectiveness Of Scaling Patterns And Controls Of Land-Atmosphere Carbon Exchange In A Shrubland Of The Chihuahuan Desert With Novel Cyberinfrastructure, Aline Jaimes

Open Access Theses & Dissertations

Over the last century, arid and semiarid regions have undergone intense desertification and in many regions, vegetation has shifted from grassland to shrubland dominated ecosystems. This land cover change has important implications for how desert ecosystems function - especially with regards to land-atmosphere exchange of carbon, water, and energy. Although the extent of desertified landscapes is expected to expand over the next 30 to 40 years, there is a relatively poor understanding of how this state transition will impact ecosystem function and feedbacks to other components of the earth system. Key to addressing this challenge is an improved understanding of …

Glycine Transporter 2: Expression And Interactions In The Central Nervous System., Shweta Lavania

Open Access Theses & Dissertations

Glycine is an important inhibitory neurotransmitter that is localized in the caudal areas of the nervous system and plays an important role in mediating many important functions related to breathing, spinal reflexes, nociception etc. Termination of neurotransmission is achieved by the re-uptake of glycine back into the pre- synaptic neuron and neighboring glial cells by the two glycine transporters namely Glycine transporter 1 (GlyT1) and Glycine transporter 2 (GlyT2). These transporters play an essential role in regulating glycinergic inhibition in the central nervous system by controlling the duration and intensity of neurotransmission and therefore the efficacy of synaptic inhibition as …

Sumoylation Affects Ns1'S Ability To Neutralize The Interferon Response, Jeanette Cecilia Gonzalez

Open Access Theses & Dissertations

It is of huge concern the possibility that at some point in the future we may face a new pandemic involving a highly pathogenic virus due to our current preventive and treatment options to fight this viral disease. The main reason for such limitations is the ability of the virus to go over constant antigenic shifts and drifts on its viral surface proteins HA and NA. The constant mutations that affect this virus cause the need of developing new vaccines for each influenza season. Periodically, the World Health Organization (WHO) reports that around 10% of the world population gets infected …

Gbetagamma-Microtubule Mediated Mechanism Of Neuronal Differentiation, Jorge Anibal Sierra Fonseca

Open Access Theses & Dissertations

Neurodegeneration, a progressive loss of nerve cells (neurons), occurs in many neurological disorders, including Alzheimer's and Parkinson's diseases, as well as in the aging brain. Disruption of microtubules in neurons and the aggregation of proteins associated with them is the hallmark of neurodegeneration. Nevertheless, the cause of this disorder is largely unknown, and no effective drugs are available to treat the disease processes. Therefore, there is a need to understand the molecular mechanisms that drive the assembly and disassembly of microtubules during neurite outgrowth and differentiation. Evidence suggests that nerve growth factor (NGF) induces neurite outgrowth from PC12 cells by …

Effects Of The Cellular Sumoylation System On The Influenza Nuclear Export Protein (Nep), Karla Prieto

Open Access Theses & Dissertations

The high genetic compatibility between the 2009 H1N1 pandemic "swine flu" and the highly pathogenic H5N1 "bird flu" viruses indicates that the odds of a deadly bird flu strain mingling its genetic material with a human virus and becoming easily transmissible among humans are at an all-time high. This fact stresses the urgent need for new treatment and prevention methods to combat influenza. Our current anti-influenza weapons include vaccination and two type of antivirals that

target specific viral components (the so-called M2 ion channel inhibitors and the neuraminidase inhibitors). However, the high genetic variability of the virus enables it to …

Il-2rβ T450 Phosphorylation Is A Positive Regulator For Receptor Complex Stability And Activation Of Signaling Molecules, Blanca Estela Ruiz-Medina

Open Access Theses & Dissertations

Homeostasis of the immune system is required for proper defense against pathogenic insult. Cells of the innate and adaptive compartments provide a strictly regulated response to clear infections while allowing for self-tolerance. Dysregulation of the components of the immune system can lead to immunodeficiency, autoimmunity, and cancer. Key players of the immune response are T, B, and NK cells, which become strongly activated by IL2 through its receptor. The β subunit of the receptor becomes tyrosine, serine, and threonine phosphorylated upon induction with IL2. Phosphorylation of tyrosine residues has been extensively studied, however, the putative regulatory role of serine and …

Identification And Characterization Of Novel Anti-Leukemia And Anti-Lymphoma Compounds, Yahaira Santiago

Open Access Theses & Dissertations

The anti-cancer properties of curcumin, the natural yellow pigment in the roots of turmeric (Curcuma longa), have been extensively described over the last century. It has been shown to interfere with multiple cell signaling pathways, including execution of apoptosis, anti-proliferation, anti-angiogenic, and anti-inflammatory properties. However, curcumin's cytotoxic potential is limited when administered in vivo. With the idea of preserving curcumin's characteristics, but improving its bioavailability, analogues have been developed and evaluated in the last decade. Most of the analogues have shown very good anti-cancer activity in various cell lines and one analogue is now in a clinical trial. Nonetheless, this …

An Avian Survey Conducted At Five Water Sources Within The Northern Chihuahuan Desert On Indio Mountains Research Station, Texas, Geoffrey Hugh Wiseman

Open Access Theses & Dissertations

The objective of this study was to conduct an avian survey of five water sources (four ephemeral former cattle tanks and one perennial spring), determine how many species inhabit or use Indio Mountains Research Station, and show a hierarchal similarity between the survey sites. This survey was conducted in a Chihuahuan Desert scrub landscape on Indio Mountains Research Station (IMRS) in Hudspeth County, Texas. There have been no previous formal studies of the avifauna at IMRS. All species accounts or sightings have been from casual sightings.

Eighty-five avian species were recorded during this project bringing the total of avian species …

Characterization Of The Disulfide In The Ectodomain Of Anthrax Toxin Receptor 2, Pedro Raymundo Jacquez

Open Access Theses & Dissertations

Anthrax toxin receptors act as molecular clamps or switches that control anthrax toxin entry, pH-dependent pore formation, and translocation of enzymatic moieties across the endosomal membranes. The ectodomain of anthrax toxin receptor 2 (ANTXR2) is composed of a von Willebrand factor A (VWA) domain that binds to anthrax toxin protective antigen (PA) and a newly defined immunoglobulin-like (Ig) domain, in which the disulfide bonds are required for PA pore formation and for the folding of ANTXR2. While the VWA domain has been well characterized, the structure and function of the whole ectodomain (VWA-Ig) are poorly defined, this is mainly due …

Evaluation Of Static And Dynamic Postural Control In Athletes With Concussions During Recovery, Nicholas Murray

Open Access Theses & Dissertations

Approximately seventy-six percent of individuals with a sport-related concussion present with reduced balance. Current Return-to-Play (RTP) protocols rely heavily on measures of static balance that are not environmentally relevant. However, due to the variable nature of symptom presentation, research has not clearly defined a requisite time for balance recovery following a sport-related concussion. The use of novel procedures such as monitoring postural control during an environmentally relevant dynamic balance tasks could refine the timeline for recovery of postural control and aid in mitigating the potential severe consequences of Second Impact Syndrome. Therefore, the purpose of this study was to investigate …

Effects Of Cerium Oxide Nanoparticles In Cereals: Insights Into The Toxicity Mechanisms And Macromolecular Modifications, Cyren Mendoza Rico

Open Access Theses & Dissertations

Despite the inundation of studies on the interaction of engineered nanomaterials (ENMs) with plants, investigations involving complete life cycle (i.e from seedling establishment to full maturity) are still lacking. Assessments on the nutritional value of plants cultivated to full maturity in ENMs-treated soil are also missing. Cerium oxide nanoparticles (nCeO2) have significant interactions with plants; however, there are no life cycle studies yet on their implications in cereals like rice (Oryza sativa L.), wheat (Triticum aestivum L.), and barley (Hordeum vulgare L.). These cereals are globally important crops that support the economic activity, and nutritional and health needs of billions …

Two-Photon Microscopy For Biomedical Studies, Yassel Acosta

Open Access Theses & Dissertations

Fluorescence optical microscopy is one of the most important tools to investigate biological samples and to observe structures in living cells. Based on the principle of the simultaneous absorption of two-photons and subsequent emission of fluorescent light we have developed a Two-Photon Laser Scanning Fluorescence Microscope that allow us to perform optical sectioning and three-dimensional reconstructions of structures in biological samples such as dopaminergic clusters of neurons and tracheal branches in Drosophila brain. The spatial confinement of the excitation light to the focal plane combined with the temporal compression of photons into short packets during femtosecond pulses make our system …

Examining The Role Of Attention In Steering Using A Dual Task Paradigm, Venkata Naga Pradeep Ambati

Open Access Theses & Dissertations

Changing the direction of locomotion, often referred to as "steering", is an integral component of human locomotion. Steering requires maintaining dynamic balance while translating and rotating the body in the new travel direction. Given the level of sensation thought to be involved in sub serving goal directed modifications in steering, it is highly likely that steering control may require attention. Since attention resources decline with increasing age, we may see the influence of age on steering performance when attention resources are limited. Therefore, this study sought to investigate the role of attention in steering using a dual task paradigm in …

Effects Of Electrical Pulse Stimulation On In Vitro Measurement Of Mitochondrial Content And Lipid In Human Myotubes, Daniel Alberto Conde

Open Access Theses & Dissertations

It has been previously shown that human myotubes retain certain in vivo characteristics of the donors. Furthermore, we have shown that Electrical pulse stimulation (EPS), an in vitro exercise mimetic, increases mitochondrial and lipid content in cultured human myotubes after 24 hr. of stimulation. Purpose: We aimed to examine the EPS induced adaptations to lipid, mitochondrial, and Glucose transporter 4 (GLUT4) content using human myotubes. Methods: EPS was applied to myotubes for 60 min (bipolar pulses of 100 Hz, 30V, every 5 seconds), 24 hr. or 48 hr. (single bipolar pulses of 1 Hz for 2 ms; 30V) and were …

Global Sphingolipid Profile Of Giardia Lamblia During Stage Differentiation: The Influence Of Sphingomyelin Abundance On Viable Cyst Production, Trevor Thomas Duarte

Open Access Theses & Dissertations

Giardia lamblia is a protozoan parasite and a major cause of the waterborne-illness, giardiasis, worldwide. Giardiasis is endemic in developing countries and is a leading cause of non-viral- and non-bacterial-associated intestinal disorders. Acute symptoms of giardiasis include diarrhea, cramps, and malabsorption. The disease is often self-limiting, although the infection can result in long-term disorders such as chronic fatigue, stunted cognitive skills, and failure to thrive even after the parasite has been cleared.

This parasite exists in two morphologic forms--infective trophozoites and transmissible, water-resistant cyst, which is passed by the fecal-oral route and is likely to be spread by contaminated drinking …

A Comparative Approach To Assessing The Functional And Structural Characteristics Of Human Fkbp52 In The Regulation Of Steroid Hormone Receptor Signaling Pathway, Diondra Crystal Harris

Open Access Theses & Dissertations

The 52 kDa FK506 binding protein (h52) is a key positive regulator of Androgen Receptor (AR) in cellular and animal models and is an attractive target for the treatment of prostate cancer. Human FKBP52 is a known regulatory protein and co-chaperone that has been shown to play an important role in the regulation of the AR signaling pathway, and in the development of the male sexual phenotype. Cellular studies in mammalian and yeast cells reveal that FKBP52 is a positive regulator of AR, glucocorticoid receptor (GR), and progesterone receptor (PR), potentiating receptor-mediated gene expression up to 60-fold in some systems. …

Revision Of The Ant Genus Bothroponera (Hymenoptera: Formicidae: Ponerinae) From The African Continent, Abdulmeneem Joma

Open Access Theses & Dissertations

Abstract (chapter 1)

The Afrotropical ants in the genus Bothroponera include the pumicosa, talpa, and sulcata species complexes. Species in the Bothroponera pumicosa species complex are mainly distributed in the southern part of Africa. This group of ants is characterized by having coarsely foveolate sculpture and by having either a raised a "v" or "u" shaped anterior medial area of the clypeus (anteclypeus), with or without a carina. The mandibles have 7 teeth in the majority of species and 8 teeth in the others. The eyes are relatively large. The scapes usually do not reach the posterior lateral corner of …

Characterization Of Membrane Interaction Of Mycobacterium Tuberculosis Esat-6, Yue Ma

Open Access Theses & Dissertations

Mycobacterium tuberculosis (Mtb) targets alveolar macrophages and has a high tolerance to the macrophage's antimicrobial effectors, such as low pH, reactive oxygen species, and reactive nitrogen species. It has been reported and widely accepted that Mtb disarms macrophages through arresting the normal maturation process of the phagosomes. Inhibition of phagosome-lysosome fusion and phagosome acidification is an effective survival strategy at the early stage of infection. This behavior allows Mtb to remain and replicate within the phagosomes of macrophages. At the later stage of infection, the pathogen translocates from the phagolysosomal compartments into the cytosol of host cells by phagolysosomal rupture. …

Functional Genomic And Proteomic Analysis Of Highly Drug Resistant Chronic Myeloid Leukemia, Derrick Matthew Oaxaca

Open Access Theses & Dissertations

Chronic Myeloid Leukemia (CML) has served as a model for how cancer can be selectively targeted with advanced forms of chemotherapies known as kinase inhibitors. Such new therapies have significantly altered the field of oncology and have led to monumental increases in both survival rates and quality of life for cancer patients. However, approximately one-third of CML patients will go on to develop drug resistance against major kinase inhibitors. Along with this, other cancers are showing increased incidences of drug resistance. Understanding how these cancers, such as CML, overcome drug sensitivity is of major importance within the clinic. To predict …

Spingolipid Metabolism In A Reptillian Protozoan, Entamoeba Invadens, Duran Dogan Debons

Open Access Theses & Dissertations

Entamoeba invadens (hereinafter E. invadens) is an anaerobic parasitic protozoan that can be found in water and soil. Although the host organisms for this parasite are snakes, lizards, and other reptile species, the parasite is morphologically identical to Entamoeba histolytica, a causative agent of human amebiasis. Entamoeba inavdens exists in two morphological forms--(1) a replicative trophozoite, and (2) a relatively dormant cyst. While the transformation of cyst to trophozoites (called "excystation") takes place in the stomach, the differentiation of trophozoites to cyst (known as "encystation"), occurs in the small intestine. Unlike the cyst, a trophozoite is unable to survive …

Characterization Of Ns1 Sumoylation And Its Effect On Influenza A Viral Infection, Katherine Anne Meraz

Open Access Theses & Dissertations

Influenza virus is a contagious respiratory virus responsible for seasonal epidemics and several catastrophic pandemics in the last century. Its genome is comprised of negative sense, single-stranded RNA and, after entering the cell, it is capable of hijacking the host cellular machinery for reproducing its own genetic material. The activation of cellular defenses against influenza viral infection are triggered upon viral entry and help regulate the course of viral infection. This study focused on the interplay between the influenza A virus and the cellular SUMOylation system during viral infection. The first part of this Dissertation deals with the relevance of …

Impact Of Zinc Oxide Nanoparticles On Green Pea Plant & Seed Quality And Effects On Physiological Traits Of Green Peas, Corn, And Zucchini By Silver Nanoparticles, Arnab Mukherjee

Open Access Theses & Dissertations

The production and use of numerous engineered nanomaterials (ENMs) have increased exponentially over the past decade. Nanoparticles (NPs), ENMs possessing diameter between 1-100 nm, (NPs), are widely used in many applications. Worldwide consumption of NPs has increased their possible release into the environment. This, in turn, has elevated the extent of the potential impacts of NP exposure to living and non-living organisms. This is why the assessment of the impact of NPs on different environmental components, especially on plants, the producer in the food web, has become a very important aspect of nano-ecotoxicology. However, studies focusing on phytotoxicity and effects …

Mechanisms To Mitigate Neurodegeneration By Maintaining Mitochondrial Health, Parijat Kabiraj

Open Access Theses & Dissertations

Cerebral accumulation of amyloidogenic protein aggregates is most frequently observed in the pathogenesis of neurodegenerative diseases. Recent studies showed prion like spreading of beta amyloid (A beta) in Alzheimer's disease (AD) and alpha synuclein protein in Parkinson's disease (PD) brain. Failure or compromise to the chaperone activity of protein disulfide isomerase (PDI) is also been reported as a major factor of aggregate formation. Nitrosative stress mediated S-nitrosylation (SNO) of protein disulfide isomerase (PDI), a housekeeping oxidoreductase, has been implicated in the pathogenesis of sporadic PD and AD. Mitochondrial dysfunction, leading to elevated levels of reactive oxygen species (ROS), is associated …

Modulation Of Vestibular Evoked Reflexes In Postural Muscles During Self-Motion Experiences In Virtual Environments, Fabricio Saucedo

Open Access Theses & Dissertations

BACKGROUND & AIM: Maintaining posture requires the input from three primary sensory systems. These systems include somatosensory, visual, and vestibular components. Of these three systems, the visual and vestibular systems work closest to maintain balance and posture due to visual-vestibular interactions that take place during static and dynamic activities. They are mainly responsible for identifying stimuli and using sensory information to orient the body in space. Thus, understanding how visual and vestibular components integrate may be critical to understand how visual and vestibular sensory information is weighted to control balance. The purpose of this investigation was to determine if visual …