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Identification and Characterization of Genes Required for Symbiotic Nitrogen Fixation in Medicago truncatula Tnt1 Insertion Mutants

Description: In this dissertation I am using M. truncatula as a model legume that forms indeterminate nodules with rhizobia under limited nitrogen conditions. I take advantage of an M. truncatula Tnt1 mutant population that provides a useful resource to uncover and characterize novel genes. Here, I focused on several objectives. First, I carried out forward and reverse genetic screening of M. truncatula Tnt1 mutant populations to uncover novel genes involved in symbiotic nitrogen fixation. Second, I focused… more
This item is restricted from view until August 1, 2028.
Date: July 2023
Creator: Cai, Jingya
Item Type: Refine your search to only Thesis or Dissertation
open access

Identification and Characterization of the Pyrimidine Biosynthetic Operon in Streptomyces griseus

Description: To further understand the ATCase/DHOase bifunctional complex formed in Streptomyces, the genes encoding these and other pyrimidine enzymes were identified and characterized. Polymerase chain reaction (PCR) was utilized in this effort. Primers were constructed by selecting conserved regions of pyrimidine genes from known gene and protein sequences of a wide variety of organisms. These sequences were then optimized to Streptomyces codon usage. PCR products were obtained from internal sites within… more
Date: May 1998
Creator: Hooten, Jody J. (Jody Jeran)
Item Type: Refine your search to only Thesis or Dissertation

Identification and Characterization of Two Putative Sulfate Transporters Essential for Symbiotic Nitrogen Fixation in Medicago truncatula

Description: The process of symbiotic nitrogen fixation (SNF) in legume root nodules requires the channeling and exchange of nutrients within and between the host plant cells and between the plant cells and their resident rhizobia. Using a forward genetics approach in the Medicago truncatula Tnt1 mutant population followed by whole genome sequencing, two putative sulfate transporter genes, MtSULTR3;5 and MtSULTR3;4b, were identified. To support the hypothesis that the defective putative sulfate transporter … more
This item is restricted from view until January 1, 2025.
Date: December 2022
Creator: Pradhan, Rajashree
Item Type: Refine your search to only Thesis or Dissertation
open access

Identification and quantification of lipid metabolites in cotton fibers: Reconciliation with metabolic pathway predictions from DNA databases.

Description: The lipid composition of cotton (Gossypium hirsutum, L) fibers was determined. Fatty acid profiles revealed that linolenate and palmitate were the most abundant fatty acids present in fiber cells. Phosphatidylcholine was the predominant lipid class in fiber cells, while phosphatidylethanolamine, phosphatidylinositol and digalactosyldiacylglycerol were also prevalent. An unusually high amount of phosphatidic acid was observed in frozen cotton fibers. Phospholipase D activity assays revealed that… more
Date: May 2004
Creator: Wanjie, Sylvia W.
Item Type: Refine your search to only Thesis or Dissertation

Identification, Characterization and Engineering of UDP-Glucuronosyltransferases for Synthesis of Flavonoid Glucuronides

Description: Flavonoids are polyphenolics compounds that constitute a major group of plant specialized metabolites, biosynthesized via the phenylpropanoid/polymalonate pathways. The resulting specialized metabolites can be due to decoration of flavonoid compounds with sugars, usually glucose, by the action of regiospecific UDP-glycosyltransferase (UGT) enzymes. In some cases, glycosylation can involve enzymatic attachment of other sugar moieties, such as glucuronic acid, galactose, rhamnose or arabinose. Th… more
Date: December 2020
Creator: Adiji, Olubu Adeoye
Item Type: Refine your search to only Thesis or Dissertation
open access

Identification of a Potential Factor Affecting Graduation Rates in STEM for Hispanic Students at the University of North Texas, via Analysis of Nonfiction Science Books in Spanish Language for ELLs in the Dallas ISD Schools

Description: Latinos are the largest minority group in the U.S.; however despite the continuous growth of the Hispanic population, Latinos are severely underrepresented in STEM fields. One of the reasons that might explain why Latinos do not major in STEM is the way they encounter science curriculum in primary school. Students' limited proficiency in English may constrain their science achievement when instruction is delivered exclusively in English. A quantitative analysis with graduation rates in STEM fro… more
Date: August 2016
Creator: Garcia Colin, Monica
Item Type: Refine your search to only Thesis or Dissertation
open access

Identification of Genes Involved in Flocculation by Whole Genome Sequencing of Thauera aminoaromatica Strain MZ1T Floc-defective Mutants

Description: Thauera aminoaromatica MZ1T, a floc-forming bacterium isolated from an industrial activated sludge wastewater treatment plant, overproduces exopolysaccharide (EPS) leading to viscous bulking. This phenomenon results in poor sludge settling and dewatering during the clarification process. To identify genes responsible for bacterial flocculation, a whole genome phenotypic sequencing technique was applied. Genomic DNA of MZ1T flocculation-deficient mutants were subjected to massively parallel sequ… more
Date: December 2015
Creator: Prombutara, Pinidphon
Item Type: Refine your search to only Thesis or Dissertation
open access

Identification of Glycine as the Factor in Peptone Which Induces Pleomorphism in Azotobacter Vinelandii

Description: The rigid peptidoglycan layer of the cell wall is responsible for maintaining the structural integrity of bacteria. Antibiotics such as penicillin exert their anti-bacterial effect by inhibiting synthesis of peptodoglycan, and enzymes such as lysozyme destroy cell integrity by hydrolyzing specific bonds in the interior of this macromolecule. Defective cells can no longer withstand the high turgor pressure within the cell because they are no longer protected by a rigid wall and tend to become fr… more
Date: December 1972
Creator: Rosenthal, Raoul Simon
Item Type: Refine your search to only Thesis or Dissertation
open access

Identification of Hox Genes Controlling Thrombopoiesis in Zebrafish

Description: Thrombocytes are functional equivalents of mammalian platelets and also possess megakaryocyte features. It has been shown earlier that hox genes play a role in megakaryocyte development. Our earlier microarray analysis showed five hox genes, hoxa10b, hoxb2a, hoxc5a, hoxc11b and hoxd3a, were upregulated in zebrafish thrombocytes. However, there is no comprehensive study of genome wide scan of all the hox genes playing a role in megakaryopoiesis. I first measured the expression levels of each of … more
Date: December 2015
Creator: Sundaramoorthi, Hemalatha
Item Type: Refine your search to only Thesis or Dissertation
open access

Identification of the Neurobiological Basis of Hemodynamic Responses Correlated with Cognitive Stroop Task Performance After an Acute Bout of Aerobic Exercise

Description: Cardiovascular activities may increase the brain blood flow improving neuronal activities leading to improved cognition. Consequently, the effects of an acute bout of moderate intensity aerobic exercise on brain hemodynamics and its correlation with cognitive color-word Stroop task performance were tested. The Stroop tasks were congruent (color matches word) and incongruent (color does not match word). Prefrontal (PFC) and motor cortex (MC) blood flow was recorded by fNIRS (functional near-infr… more
Date: May 2018
Creator: Pal, Amrita
Item Type: Refine your search to only Thesis or Dissertation
open access

Identification of Three Symbiosome Targeting Domains in the MtENOD8 Protein and Cell-to-cell MtENOD8 mRNA Movement in Nodules

Description: The model legume, Medicago truncatula, is able to enter into a symbiotic relationship with soil bacteria, known as rhizobia. This relationship involves a carbon for nitrogen exchange in which the plant provides reduced carbon from photosynthesis in exchange for reduced, or “fixed” atmospheric nitrogen, which allows the plant to thrive in nitrogen depleted soils. Rhizobia infect and enter plant root organs, known as nodules, where they reside inside the plant cell in a novel organelle, known a… more
Date: May 2012
Creator: Meckfessel, Matthew Harold
Item Type: Refine your search to only Thesis or Dissertation
open access

Identifying genetic interactions of the spindle checkpoint in Caenorhabditis elegans.

Description: Faithful segregation of chromosomes is ensured by the spindle checkpoint. If a kinetochore does not correctly attach to a microtubule the spindle checkpoint stops cell cycle progression until all chromosomes are attached to microtubules or tension is experienced while pulling the chromosomes. The C. elegans gene, san-1, is required for spindle checkpoint function and anoxia survival. To further understand the role of san-1 in the spindle checkpoint, an RNAi screen was conducted to identify gen… more
Date: May 2009
Creator: Stewart, Neil
Item Type: Refine your search to only Thesis or Dissertation
open access

Immune Response of the Rat to Outer Membrane Proteins of Legionella Pneumophila

Description: Outer membrane proteins (OMPs) were recovered from eleven strains (eight serogroups) of Legionella pneumophila by sequential treatment with Tris buffer (pH 8), citrate buffer(pH 2.75) and Tris buffer (pH 8). Transmission electron microscopy revealed clearly the separation of the outer membrane from the bacteria. The development of delayed hypersensitivity was also noted by measuring the area of arythema and induration produced by intradermal injections of the MPSs from Chicago 8 strain. The adj… more
Date: August 1985
Creator: Ahanotu, Ejemihu Ndu
Item Type: Refine your search to only Thesis or Dissertation
open access

Immunocompetence in the AKR Mouse

Description: A model for the study of the relationship of immunity to cancer is found in AKR mice which harbor Gross virus. This genetically transmitted virus is present in a latent form for months before it spontaneously induces leukemia. Many investigators have demonstrated near normal humoral responses, but abnormal cellular immunity in the preleukemic animal. With increasing age, pathology of the disease is expressed, reflecting diminished immunity. In this study, the ontogeny of humoral antibodies of A… more
Date: August 1976
Creator: Dunton, Helen
Item Type: Refine your search to only Thesis or Dissertation
open access

Immunohistochemical characterization of neuronal cilia in the rat central nervous system.

Description: An anti-G"11 antibody was used to label neuronal cilia throughout the rat central nervous system. Immunoreactive cilia were observed in every examined region of the rat CNS, but not in monkey or mouse tissue. Antibodies to G"q and G"q/11 failed to label cilia. Immunoreactive cilia were observed as early as postnatal day 0 in spinal tissue, and postnatal day 3 in hypothalamic tissue. There was a statistically significant negative correlation between a region's mean cilium length and that region… more
Date: May 2002
Creator: Hughes, Rhome
Item Type: Refine your search to only Thesis or Dissertation
open access

Immunohistochemistry of the Gills of the Channel Catfish Ictalurus Punctatus: Cells and Neurochemicals That May Be Involved in the Control of Cardioventilatory Reflexes

Description: In teleost fishes the neurochemicals involved in sensing and responding to hypoxia are unresolved. Serotonergic branchial neuroepithelial cells (NECs) are putative O2 chemoreceptors believed to be homologous to the neural crest (NC) derived APUD (amine-precursor uptake and decarboxylation) pulmonary NECs and carotid body type-1 glomus cells. Branchial NECs contain serotonin (5-HT), thought to be central to the induction of the hypoxic cardioventilatory reflexes. However, application of 5-HT … more
Date: December 2013
Creator: Oden, David S.
Item Type: Refine your search to only Thesis or Dissertation
open access

An Immunological Study of Adults with Down Syndrome

Description: The high susceptibility to infection in persons with Down Syndrome (DS) has led some investigators to explore the possibility of a defect in the immune system. Studies to date indicate no defect in humoral immunity suggesting that the defect might be in the cellular immune functions, but no specific defect has been found. Our investigation of the cellular immune system of adult DS patients was conducted by examining (1) the number and function of T-lymphocytes, (2) the phagocytic function of gr… more
Date: August 1983
Creator: White, Olivia Masih
Item Type: Refine your search to only Thesis or Dissertation
open access

Immunotoxicity of Chromium Contaminated Soil in the Earthworm, Lumbricus Terrestris

Description: Objective was to assess the toxicity of chromium (Cr) contaminated soil (CS) using the earthworm Lumbricus terrestris. Specific aims were to determine: (1) survival (LC50); .(2) immunotoxicity as indicated by lysozyme activity, coelomocyte counts, secretory (SR) and erythrocyte rosette (ER) formation, and phagocytosis; and (3) compare effects of CS exposure with those of Cr spiked artificial soil (AS) . CS Cr concentration was 8.78 mg/g with 98.2% being Cr^3+ and 1.8% being Cr^6+. Using 14 d AS… more
Date: May 1993
Creator: Mohammadian, Gholamreza
Item Type: Refine your search to only Thesis or Dissertation

Impact of Anti-S2 Peptides on a Variety of Muscle Myosin S2 Isoforms and Hypertrophic Cardiomyopathy Mutants Revealed by Fluorescence Resonance Energy Transfer and Gravitational Force Spectroscopy

Description: Myosin subfragment-2 (S2) is an intrinsically unstable coiled coil. This dissertation tests if the mechanical stability of myosin S2 would influence the availability of myosin S1 heads to actin thin filaments. The elevated instability in myosin S2 coiled coil could be one of the causes for hypercontractility in Familial Hypertrophic Cardiomyopathy (FHC). As hypothesized FHC mutations, namely E924K and E930del, in myosin S2 displayed an unstable myosin S2 coiled coil compared to wild type as mea… more
Date: August 2020
Creator: Aboonasrshiraz, Negar
Item Type: Refine your search to only Thesis or Dissertation
open access

The impact of climate and flooding on tree ring growth of Fraxinus pennsylvanica in north-central Texas.

Description: Tree cores of Fraxinus pennsylvanica were used in a dendrochronological analysis investigating the species' responses to climate and flooding. The objective was to develop a model that incorporates the effects of precipitation, temperature, and flooding on radial growth in this species in north-central Texas. The trees exhibited strong climatic signals. The study clearly shows that all three factors have significant impacts on tree ring growth both prior to and during growth; however, the natur… more
Date: December 2009
Creator: Komperod, Mari
Item Type: Refine your search to only Thesis or Dissertation

The Impact of Invasive Salmonids on Ecosystem Functioning in South America's Sub-Antarctic Inland and Marine Waters

Description: Invasions from coho salmon were first reported in the Cape Horn Biosphere Reserve (CHBR) in 2019 which is the most southern distribution registered to date. The CHBR is known for its high number of endemic species and unique biodiversity, such as the native fishes Galaxias maculatus and Aplochiton taeniatus. There are now three invasive salmonid species in the rivers of CHBR and are a potential threat to the native fish taxa. Stable isotope and gut content analysis were used to understand resou… more
This item is restricted from view until June 1, 2025.
Date: May 2023
Creator: Moore, Sabrina
Item Type: Refine your search to only Thesis or Dissertation
open access

The impact of invertebrates to four aquatic macrophytes: Potamogeton nodosus, P. illinoensis, Vallisneria americana and Nymphaea mexicana.

Description: This research investigated the impact of invertebrates to four species of native aquatic macrophytes: V. americana, P. nodosus, P. illinoensis, and N. mexicana. Two treatments were utilized on each plant species, an insecticide treatment to remove most invertebrates and a non-treated control. Ten herbivore taxa were collected during the duration of the study including; Synclita, Paraponyx, Donacia, Rhopalosiphum, and Hydrellia. Macrophyte biomass differences between treatments were not measu… more
Date: August 2008
Creator: Nachtrieb, Julie Graham
Item Type: Refine your search to only Thesis or Dissertation
open access

Impaired virulence factor production in a dihydroorotate dehydrogenase mutant (pyrD) of Pseudomonas aeruginosa.

Description: Previous research in our laboratory showed that when knockout mutations were created in the pyrB and pyrC genes of the pyrimidine pathway in Pseudomonas aeruginosa, not only were the resultant mutants auxotrophic for pyrimidines but they were also impaired in virulence factor production. Such a correlation had not been previously reported for P. aeruginosa, a ubiquitous opportunistic pathogen in humans. In an earlier study it was reported that mutants blocked in one of the first three enzymes … more
Date: December 2005
Creator: Ralli, Pooja
Item Type: Refine your search to only Thesis or Dissertation
open access

Implications of Diet in Cardiovascular Disease Risk: Postprandial Changes in Circulating Monocytes and Endotoxemia

Description: It is well established that continual consumption of a diet high in fat leads to the development of chronic conditions such as obesity, cardio metabolic syndrome, and atherosclerosis that are associated with high incidence of cardiovascular disease. Recent studies have identified endotoxin-derived inflammation as a major diving force for the development of these conditions. Our laboratory has recently demonstrated that consumption of a single high-fat meal results in acute postprandial endotoxe… more
Date: August 2018
Creator: Venable, Andrea Henning
Item Type: Refine your search to only Thesis or Dissertation
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