UNT Libraries - 831 Matching Results

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Molecular and Kinetic Characterization of the Aspartate Transcarbamoylase Dihydroorotase Complex in Pseudomonas putida

Description: Aerobic Gram negative bacteria such as Pseudomonas putida were reported to possess class A ATCases and to have a M.W. of 360 kD. The nucleotide sequence of the P. putida pyrBC was determined to answer this question once and for all. The expected regulatory gene was not found. It is shown that the P. putida pyrB gene is overlapped by pyrC by 4 bp. The P.putida pyrB is 1005 bp (335 aa) in length and the pyrC is 1275 bp (425 aa) long. Both of these genes complement E. coli mutants with their respe… more
Date: May 1992
Creator: Schurr, Michael J. (Michael John)
Item Type: Refine your search to only Thesis or Dissertation
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Molecular Cloning and Functional Analysis of Transposable Mercury Resistance Genes Encoded by the OCT Plasmid

Description: Translocation of a 17.1 kilobase region of the OCT plasmid encoding mercury resistance (mer) in Pseudomonas putida was shown to occur in a recombination-deficient host with plasmid PP1 serving as a recipient replicon. The frequency of transposition in Pseudomonas was estimated at 10^3 -10 -^2, but undetectable in Escherichia soli. ' DNA comprising all of mr as well as subregions there of were cloned and subjected to DNA sequence analysis. Like other transposons, mer was found to contain inverte… more
Date: August 1991
Creator: Wang, Chien-Sao
Item Type: Refine your search to only Thesis or Dissertation
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Molecular Mechanism of Action of Steroid Hormone Receptors

Description: A novel bacterial expression system that is capable of producing high levels of soluble, stable, biologically active human vitamin D3 and estrogen receptors has been developed. The method utilizes ubiquitin fusion technology and a low temperature nalidixic acid induction of the lambda PL promoter. This system can produce large quantities of receptor antigen, but only a small fraction displays wild-type DNA and hormone binding properties. Therefore, the use of this system to overproduce receptor… more
Date: May 1992
Creator: Nawaz, Zafar
Item Type: Refine your search to only Thesis or Dissertation
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Molecular Phylogeny and Evolution of the American Woodrats, Genus Neotoma (Muridae)

Description: The evolutionary relationships of woodrats (Neotoma) were elulcidated through phylogenetic analyses of mitochondrial DNA restriction site and allozyme data. DNA samples from eleven nominal species from the genus Neotoma and two outgroup taxa, Ototylomys phyttotis and Xenomys nelsoni, were cleaved using a suite of 17 Type II restriction endonucleases. Mitochondrial DNA restriction profiles were visualized following electrophoresis of restriction digests via methods of Southern transfer and hybri… more
Date: August 1992
Creator: Planz, John Valentine
Item Type: Refine your search to only Thesis or Dissertation
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Molecular systematics of Baird's pocket gopher (Geomys breviceps)

Description: Baird's pocket gopher (Geomys breviceps) is found in eastern Texas, eastern Oklahoma, central and western Arkansas, and western Louisiana. The cytochrome-b gene was sequenced and analyzed for 16 pocket gophers from throughout the range of the species. Similar phylogenetic trees were obtained using maximum-parsimony, maximum-likelihood, neighbor-joining, and Bayesian analyses. Two major clades were formed with northern individuals belonging to clade I and southern individuals belonging to clade … more
Date: August 2010
Creator: Bodine, Deanna Martinez
Item Type: Refine your search to only Thesis or Dissertation
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Monitoring Monocyte Oxldl Phagocytosis As a Cardiovascular Disease Risk Factor Following a High-fat Meal

Description: Macrophage-derived foam cells play a predominant role in the deposition of arterial plaques during the early stages of atherosclerosis. The deposition of arterial plaques is known to be effected by several factors, including a person’s dietary habits. The consumption of a high-fat (>60% of calories from fat) meal is known to elevate serum LDL and triglycerides, which have been previously implicated in the formation pf foam cells. One limitation of current research models is that it is not possi… more
Date: December 2014
Creator: Henning, Andrea L.
Item Type: Refine your search to only Thesis or Dissertation
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Morphological and Hematological Responses to Hypoxia During Development in the Japanese quail, Coturnix coturnix

Description: Hypoxic responses in quail development differ depending upon stage, duration and level of oxygen partial pressure of embryo. Incubation was switched to/from 110mmHg partial pressure (hypoxia), to/from 150mmHg (normoxia) during different stages in development, and control was incubated in normoxia throughout. Hatchability and embryo survival resulted in no hatchlings in continuous hypoxia. Responses to various hypoxic exposures throughout development resulted in recovery/repair of hypoxic damage… more
Date: May 2003
Creator: Elmonoufy, Nourhan
Item Type: Refine your search to only Thesis or Dissertation
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Morphological and Immunological Characterization of Earthworm Lumbricus terrestris Coelomocytes

Description: This research defines the morphological characteristics of the immune cells, coelomocytes, of the earthworm, Lumbricus terrestris. Such a definition of coelomocyte morphology can be correlated with immune function which will be of value in the development of a nonmammalian surrogate system to assess the immunotoxic potential of a terrestrial xenobiotics. Earthworms exposed to artificial soil dilutions of two complex xenobiotic mixtures, refuse derived fuel fly ash and a Superfund sire soil demo… more
Date: August 1992
Creator: Hariri, Maryam Feili
Item Type: Refine your search to only Thesis or Dissertation
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Morphological and Physiological Changes in Micrococcus Pyogenes Var. Aureus during Development of its Resistance to Terramycin

Description: The problem in this investigation consists of, first, the procurement of several strains of Micrococcus pyogenes var. aureus; second, the comparison of the degree and rate of development of resistance of these organisms to terramycin; and, third, to study the morphological and physiological changes which occur during the development of resistance.
Date: August 1959
Creator: Watson, Gerald T.
Item Type: Refine your search to only Thesis or Dissertation
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Morphological and physiological developmental consequences of parental effects in the chicken embryo (Gallus gallus domesticus) and the zebrafish larva (Danio rerio).

Description: Cardiac, metabolic and growth response of early-stage chicken embryos to perturbations in yolk environment was investigated. Also, effects of parental hypoxia exposure on hypoxia resistance, thermal tolerance and body length of zebrafish larvae were investigated. In the first study, thyroxine, triiodothyronine and testosterone produced differential effects on heart rate and development rate of chicken embryos during the first 4 days of development. Triiodothyronine caused a dose-dependent inc… more
Date: August 2008
Creator: Ho, Dao H.
Item Type: Refine your search to only Thesis or Dissertation
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Mouse cortical cholinergic neurons: Ontogeny of phenotypes in vivo and in vitro.

Description: The development of cholinergic neurons in mouse frontal cortex was studied both in vivo and in vitro by immunocytochemistry with an antibody to choline acetyltransferase (ChAT), the enzyme responsible for acetylcholine synthesis. While cortical cholinergic neurons have previously been characterized in rat cortex, up until very recently, intrinsic cortical cholinergic neurons were considered to be absent in mouse, and little is known about their development or phenotypic characteristics. The pr… more
Date: August 2005
Creator: Coiculescu, Olivia Elena
Item Type: Refine your search to only Thesis or Dissertation
open access

Multi-Level Effects of Oxygen Exposure in Endothermic Insects

Description: This dissertation examined the phenotypic plasticity of endothermic, flight and respiratory physiology in response to developmental oxygen exposure in the moth Manduca sexta. Development in both 10% O2 hypoxia and 30% O2 hyperoxia treatments were used to look at the physiological consequence on both ends of the oxygen spectrum. Hypoxic insects reached smaller sizes as adults and had longer pupation lengths than controls. Hyperoxic insects were larger at the end of the larval stage, had increase… more
Date: August 2022
Creator: Wilmsen, Sara M
Item Type: Refine your search to only Thesis or Dissertation
open access

A Multiphasic Study of the Interaction Between the Branchiobdellid Cambarincola Vitrea and its Crayfish Host Procambarus Simulans

Description: The host-parasite interface between the branchiobdellid Cambarincola vitrea Ellis and its crayfish host is investigated along ecological, ultrastructural, serological, and endocrinological lines of evidence. Monthly analysis of a natural branchiobdellid from a vernal habitat demonstrates the annelid to be particularly sensitive to changes involving both the physical habitat as well as the host crayfish.
Date: August 1973
Creator: Koepp, Stephen John
Item Type: Refine your search to only Thesis or Dissertation

Multiple Dimensions of Fish Functional Traits, Trait Relationships, and Associations with Community Structure and Dynamics

Description: Trait-based approaches are useful in ecological research because of their potential ability to predict species responses from patterns present in the community and to infer mechanisms driving community assembly. Current approaches for fishes are lacking traits across all five fundamental niche dimensions (i.e. habitat, life history, trophic, metabolic and defense). This study quantified a broad range of fish functional traits across all five niche dimensions (commonly used traits and novel trai… more
Date: December 2021
Creator: Harried, Brittany Lee
Item Type: Refine your search to only Thesis or Dissertation
open access

Multivariate Analyses of Amphibian and Reptilian Distribution in Texas

Description: Presence-absence data for amphibians, chelonians, saurians, ophidians, and the terrestrial and aquatic ecological guilds of reptilians were analyzed using multivariate analyses. Geographically consistant distributional patterns were found for all faunal groupings. The correspondence between analyses of the different taxa and guilds was not perfect, but similarities were found. All analyses agreed on the presence of a distinctive region in east Texas. Most analyses also agreed on the presence of… more
Date: August 1988
Creator: Ward, Rocky
Item Type: Refine your search to only Thesis or Dissertation
open access

Museum education: Creation, implementation, and evaluation of a web-based Elm Fork Natural Heritage Museum

Description: Evaluation of museum audiences both in their physical and web-based spaces is a necessary component of museum education. For smaller museums without the personnel or knowledge to create a website and evaluate the on-line audience, using a web-based learning tool may be able to help these museums properly maintain an online site. A web-based Elm Fork Natural Heritage Museum (WBEFNHM) was created during the 2008 fall semester at the University of North Texas. The site included photographs and … more
Date: December 2010
Creator: Lundeen, Melissa
Item Type: Refine your search to only Thesis or Dissertation
open access

Mutagenic Potential of Tetramethylthiuram Disulfide (42-S Thiram) on the Germ Cell Stages of Drosophila melanogaster

Description: Tetramethylthiuram disulfide (42-S Thiram), a carbamate fungicide was studied for its mutagenic potential on the germ cell stages of wild-type male Drosophila melanogaster. The mutagenicity was tested using the sex-linked recessive lethal assay (SLRL). Any lethals induced in the F2 generation were evidenced by the absence of wild-type males. Although there was an increase in mutation rates in the 42-S Thiram treated wild-type males over the control wild-type males, it was not significantly high… more
Date: December 1990
Creator: Lowe-Chatham, Janice E. (Janice Elaine)
Item Type: Refine your search to only Thesis or Dissertation
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Mutation of Polaris, an Intraflagellar Transport Protein, Shortens Neuronal Cilia

Description: Primary cilia are non-motile organelles having 9+0 microtubules that project from the basal body of the cell. While the main purpose of motile cilia in mammalian cells is to move fluid or mucus over the cell surface, the purpose of primary cilia has remained elusive for the most part. Primary cilia are shortened in the kidney tubules of Tg737orpk mice, which have polycystic kidney disease due to ciliary defects. The product of the Tg737 gene is polaris, which is directly involved in a microtub… more
Date: August 2005
Creator: Mahato, Deependra
Item Type: Refine your search to only Thesis or Dissertation
open access

Nesting Ecology of the Dickcissel (Spiza americana) on a Tallgrass Prairie Relict in North Central Texas

Description: Eighty-three species of vascular plants were inventoried on the prairie relict during peak dickcissel nesting. Based on foliar cover and occurrence frequency, the five dominant plants were heath aster (Aster ericoides), eastern gammagrass (Tripsacum dactyloides), little bluestem (Schizachyrium scoparium), sensitive briar (Schrankia roemeriana) and meadow dropseed (Sporobolus asper). Sixty-one percent of dickcissel nests were constructed on or immediately next to three plant species: eastern gam… more
Date: May 1993
Creator: Steigman, Kenneth Lee
Item Type: Refine your search to only Thesis or Dissertation
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Neurological Responses to a Glucose Diet in Caenorhabditis elegans

Description: TRPV channels play a role in both mammalian insulin signaling, with TRPV1 expression in pancreatic beta-cells, and in C. elegans insulin-like signaling through expression of OSM-9, OCR-1, and OCR-2 in stress response pathways. In response to a glucose-supplemented diet, C. elegans are know to have sensitivity to anoxic stress, exhibit chemotaxis attraction, and display reduced egg-laying rate. Transcriptome analysis reveals that glucose stimulates nervous system activity with increased transcri… more
Date: August 2017
Creator: Dumesnil, Dennis
Item Type: Refine your search to only Thesis or Dissertation
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Neuronal Network Analyses in vitro of Acute Individual and Combined Responses to Fluoxetine and Ethanol

Description: Embryonic murine neuronal networks cultured on microelectrode arrays were used to quantify acute electrophysiological effects of fluoxetine and ethanol. Spontaneously active frontal cortex cultures showed highly repeatable, dose-dependent sensitivities to both compounds. Cultures began to respond to fluoxetine at 3 µM and were shut off at 10-16 µM. EC50s mean ± S.D. for spike and burst rates were 4.1 ± 1.5 µM and 4.5 ± 1.1 µM (n=14). The fluoxetine inhibition was reversible and without effect… more
Date: August 2002
Creator: Xia,Yun
Item Type: Refine your search to only Thesis or Dissertation
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Neuronal Survival After Dendrite Amputation: Investigation of Injury Current Blockage

Description: After dendrite transection, two primary injury current pathways may acount for cell death: (1) the lesion current at the site of injury and (2) the voltage sensitive calcium channels along the dendrite. Lesions were made with a laser microbeam in mouse spinal monolayer cell cultures. Polylysine was tried as a positively charged "molecular bandage" to block the lesion current. The calcium channel blockers, verapamil and nifedipine, were used to reduce the calcium channel current. Control toxicit… more
Date: December 1988
Creator: Shi, Ri Yi
Item Type: Refine your search to only Thesis or Dissertation
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Neuropharmacological Characteristics of Tolerance for Cocaine Used as a Discriminative Stimulus

Description: The main purpose of this research was to investigate the phenomenon of tolerance to cocaine. Tolerance is operationally defined as a decreased drug effect due to prior history of drug administration. The animal model that was chosen to investigate tolerance to cocaine was the drug discrimination model, which is an animal analogue of human subjective drug effects. In the drug discrimination procedure, animals are trained to emit one behavior when injected with saline. In the present experimen… more
Date: August 1987
Creator: Wood, Douglas M. (Douglas Michael)
Item Type: Refine your search to only Thesis or Dissertation
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