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UNT Theses and Dissertations - Browse

Nicotinic Acetylcholine Receptor α3 mRNA in Rat Visual System After Monocular Deprivation
In situ hybridization was used to examine effects of monocular enucleation on nicotinic acetylcholine receptor subunit cc3 mRNA in the rat dLGNand visual cortex. After 28 days postoperative, there were no significant differences in α3 mRNA density between the contralateral (deprived) and ipsilateral (non-deprived) sides. The lack of obvious effects of visual deprivation on α3 mRNA density suggests that other factors, possibly intrinsic to dLGNand visual cortex, govern the postnatal expression of α3 mRNA.
Unique applications of cultured neuronal networks in pharmacology, toxicology, and basic neuroscience
This dissertation research explored the capabilities of neuronal networks grown on substrate integrated microelectrode arrays in vitro with emphasis on utilizing such preparations in three specific application domains: pharmacology and drug development, biosensors and neurotoxicology, and the study of burst and synaptic mechanisms. Chapter 1 details the testing of seven novel AChE inhibitors, demonstrating that neuronal networks rapidly detect small molecular differences in closely related compounds, and reveal information about their probable physiological effects that are not attainable through biochemical characterization alone. Chapter 2 shows how neuronal networks may be used to classify and characterize an unknown compound. The compound, trimethylol propane phosphate (TMPP) elicited changes in network activity that resembled those induced by bicuculline, a known epileptogenic. Further work determined that TMPP produces its effects on network activity through a competitive inhibition of the GABAA receptor. This demonstrates that neuronal networks can provide rapid, reliable warning of the presence of toxic substances, and from the manner in which the spontaneous activity changes provide information on the class of compound present and its potential physiological effects. Additional simple pharmacological tests can provide valuable information on primary mechanisms involved in the altered neuronal network responses. Chapter 3 explores the effects produced by a radical simplification of synaptic driving forces. With all synaptic interactions pharmacologically limited to those mediated through the NMDA synapse, spinal cord networks exhibited an extremely regular burst oscillation characterized by a period of 2.9 ± 0.3 s, with mean coefficients of variation of 3.7, 4.7, and 4.9 % for burst rate, burst duration, and inter-burst interval, respectively (16 separate cultures). The reliability of expression of this oscillation suggests that it may represent a fundamental mechanism of importance during periods of NMDA receptor dominated activity, such as embryonic and early postnatal development. NMDA synapse mediated activity produces a precise ...
Light Spectra Distributions in Temperate Conifer-Forest Canopy Gaps, Oregon and in Tropical Cloud-Forest Canopy, Venezuela
Light spectra distributions were measured in two different montane forests: temperate and tropical. Spectral light measurements were made in different sized canopy gaps in the conifer forest at H. J. Andrews Experimental Forest in Oregon, USA. Researchers at Oregon State University created these gaps of 20 m, 30 m, and 50 m in diameter. In the tropical cloud forest, spectral light measurements were made in two plots that were permanently established at La Mucuy Parque Nacional in Venezuela, in collaboration with researchers at Universidad de Los Andes. In both studies, spectra and distributions of physiologically active light were analyzed: red, far-red, R/FR ratio, and blue light.
Analysis of Phytoplankton Responses to Water Chemistry Dynamics in a Moderately Eutrophic North Texas Reservoir
Canonical correspondence analysis (CCA) was used to explore relationships between measured environmental variables and in situ phytoplankton communities in a moderately eutrophic North Texas Reservoir.
Advanced Molecular and Microbial Techniques: a Complete Laboratory Notebook
The purpose of this project is to produce a complete and thorough notebook that may be used to supplement laboratory coursework. Its intent is to be used primarily by the students to aid them in understanding background information and the proper laboratory procedures involved in various types of experiments. The laboratory notebook is a summation of all the experiments and procedures used in the six-credit hour Advanced Microbial and Molecular Biology (BIOL 5160) course offered during the summer semester at the University of North Texas. This class is a team taught effort by Professors O'Donovan and Kunz. The course is constructed as an intensive practice exercise to teach the student about gene mutations, biosynthetic pathways, preparation and analysis of plasmid DNA, and many other topics included in the notebook.
Regulation of Escherichia coli pyrBI Gene Expression in Pseudomonas fluorescens
Pseudomonas fluorescens does not appear to regulate the enzymes of de novo pyrimidine biosynthesis at the level of gene expression. Little or no apparent repression of pyr gene expression is observed upon addition of exogenous pyrimidines to the growth medium. The Escherichia coli pyrBI genes for aspartate transcarbamoylase (ATCase) were sized down and cloned into the broad host range plasmid, pKT230. Upon introduction into a P.fluorescenspyrB mutant strain, ATCase showed repression in response to exogenously fed pyrimidine compounds. Thus, it was possible to bring about changes in pyrimidine nucleotide pool levels and in transcriptional regulation of gene expression at the same time.
Age-Dependent Effects Of Chronic GABAA Receptor Blockade In Barrel Cortex
GABAA receptor binding is transiently increased in rat whisker barrels during the second postnatal week, at a time when neurons in the developing rat cortex are vulnerable to excitotoxic effects. To test whether these GABAA receptors might serve to protect neurons from excessive excitatory input, polymer implants containing the GABAA receptor antagonist bicuculline were placed over barrel cortex for a 4-day period in young (postnatal days 8 - 12) and adult rats. In the cortex of young, but not adult rats, the chronic blockade of GABAA receptors resulted in substantial tissue loss and neuron loss. The greater loss of neurons in young rats supports the hypothesis that a high density of GABAA receptors protects neurons from excessive excitatory input during a sensitive period in development.
Automated Low-cost Instrument for Measuring Total Column Ozone
Networks of ground-based and satellite borne instruments to measure ultraviolet (UV) sunlight and total column ozone have greatly contributed to an understanding of increased amounts of UV reaching the surface of the Earth caused by stratospheric ozone depletion. Increased UV radiation has important potential effects on human health, and agricultural and ecological systems. Observations from these networks make it possible to monitor total ozone decreases and to predict ozone recovery trends due to global efforts to curb the use of products releasing chemicals harmful to the ozone layer. Thus, continued and expanded global monitoring of ozone and UV is needed. However, existing automatic stratospheric ozone monitors are complex and expensive instruments. The main objective of this research was the development of a low-cost fully automated total column ozone monitoring instrument which, because of its affordability, will increase the number of instruments available for ground-based observations. The new instrument is based on a high-resolution fiber optic spectrometer, coupled with fiber optics that are precisely aimed by a pan and tilt positioning mechanism and with controlling programs written in commonly available software platforms which run on a personal computer. This project makes use of novel low-cost fiber optic spectrometer technology. A cost advantage is gained over available units by placing one end of the fiber outdoors to collect sunlight and convey it indoors, thereby allowing the spectrometer and computer to be placed in a controlled environment. This reduces the cost of weatherproofing and thermal compensation. Cost savings also result from a simplified sun targeting system, because only a small pan and tilt device is required to aim the lightweight fiber optic ends. Precision sun-targeting algorithms, optical filter selection, and software to derive ozone from spectral measurements by the spectrometer are a major contribution of this project. This system is a flexible platform ...
The Use of Genetic Polymorphisms and Discriminant Analysis in Evaluating Genetic Polymorphisms as a Predictor of Population
Discriminant analysis is a procedure for identifying the relationships between qualitative criterion variables and quantitative predictor variables. Data bases of genetic polymorphisms are currently available that group such polymorphisms by ethnic origin or nationality. Such information could be useful to entities that base financial determinations upon predictions of disease or to medical researchers who wish to target prevention and treatment to population groups. While the use of genetic information to make such determinations is unlawful in states and confidentiality and privacy concerns abound, methods for human “redlining” may occur. Thus, it is necessary to investigate the efficacy of the relationship of certain genetic information to ethnicity to determine if a statistical analysis can provide information concerning such relationship. The use of the statistical technique of discriminant analysis provides a tool for examining such relationship.
Neuronal Network Analyses in vitro of Acute Individual and Combined Responses to Fluoxetine and Ethanol
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 on action potential wave shapes. Ethanol showed initial inhibition at 20 mM, with spike and burst rate EC50s at 52.0 ± 17.4 mM and 56.0 ± 17.0 mM (n=15). Ethanol concentrations above 100 -140 mM led to cessation of activity. Although ethanol did not change the shape and amplitude of action potentials, unit specific effects were found. The combined application of ethanol and fluoxetine was additive. Ethanol did not potentiate the effect of fluoxetine.
Functional Neural Toxicity and Endocrine Responses in Mice Following Naphthalene Exposure
Polycyclic aromatic hydrocarbons (PAHs) are a well studied and diverse class of environmental toxicants. PAHs act via the aryl hydrocarbon receptor (AhR), and studies have suggested that PAHs may elicit neurological and estrogenic effects. Doses of PAHs between 50 to 150 ppm may elicit neurotoxicity in rodent models. The present study investigated the effects of naphthalene on in vivo steroidogenesis in Swiss Webster male mice, and in vitro neural function of Balb-C/ICR mice frontal cortex neurons. These data suggest that naphthalene may not elicit steroidogenic effects at concentrations ranging from 0.2 to 25 mg/kg/day, following a 7 day subcutaneous dosing regime. In addition, naphthalene may cause functional toxicity of frontal cortex neurons at concentrations of 32 to 160 ppm naphthalene.
A Physiological Age-Grading System for Female Hydrellia pakistanae Deonier (Diptera: Ephydridae)
Conflicting opinions about the effectiveness of H. pakistanae as a biological control agent for hydrilla prompt researchers to find a method for assessing the fly's success. Developing a physiological age-grading system for the fly using ovarian morphology to detect changes in reproductive activity is useful for evaluating reproductive status of the fly in field populations. Changes in the appearance of follicular relics in ovaries with oviposition provide a reliable method to estimate fecundity. Characteristics of follicular relics were used to develop a system with eight physiological age classes, three nulliparous and five parous. Changes that occur in the fat body were used to assist in classification of nulliparous females or those with low egg counts.
Population Dynammics in Mixed Cultures of Microorganisms
The purpose of this study was to determine the effect of substrate levels and different types of substrates on population changes of mixed cultures of Serratia marcescens and Saccharomyces cerevisiae, as compared to pure cultures.
Factors Affecting Pigment Production in Mycobacterium rhodocrous
This study was undertaken in order to isolate and identify the pigment, if possible, and to determine the effect of substrate, substrate concentration, light exposure, and pH on pigment production in this organism.
Individual, Social, and Seasonal Behavior of the Thirteen-Lined Ground Squirrel (Spermophilus tridecemlineatus)
The purpose of this study is to provide a qualitative, detailed description of individual and social behavior in a free-living population of thirteen-lined ground squirrels. Behavioral differences in relation to various periods of the annual cycle are also evaluated.
Antibody Adsorption Used in Identification of Similar Streptomyces Species
This investigation involved the production of specific antisera against known International Streptomyces project strains of Streptomyces.
Metabolism of Methylglyoxal by Scenedesmus Quadricauda
The purpose of this study was to investigate the metabolic pathways of methylglyoxal in S. quadricauda.
Studies on Microorganisms in Jet Aircraft Fuel Systems
Laboratory and field investigations during the past ten years have demonstrated that certain microorganisms can cause deleterious effects in jet fuel tank systems. These investigations have brought about new concepts concerning the mechanisms of utilization of certain constituents in jet fuel tanks by microorganisms. Since the presence of microorganisms is inevitable in fuel systems, research efforts have been directed towards identification and determination of the types of microorganisms which can utilize jet fuel hydrocarbons, fuel additives, polyurethane foam structural materials, and particular hydrocarbons present in the fuel.
Terrestrial Vertebrates of Fannin County, Texas
The purposes of this thesis were (1) to provide some knowledge of the herptiles and mammals of this area, (2) to clarify the distribution of many of these animals in this section of Texas, and (3) to provide additional ecological information about the area.
An Ecological Survey of the Reptiles and Amphibians of Wise county, Texas
The purpose of this study was to record the relationships between the reptiles and amphibians of Wise County and the ecological subdivisions of the area. Wise County was chosen because of the heterogenity of the area and because of its proximity to other counties which have been previously and similarly studied.
Growth Inhibition of Chlorella Pyrenoidosa TX71105 by an Unknown Soil Bacillus
The purpose of this paper is to present data on the nature of mixed cultures of algae and bacteria and to report new evidence of growth inhibition of Chlorella by a bacterial contaminant isolated from a soil environment.
The Effects of Simulated Altitude on the Intestinal Flora of Guinea Pigs
The purpose of this paper is to report the results of studies on the aerobic, mesophilic intestinal flora of guinea pigs subjected to conditions similar to those encountered by man in spacecraft.
Distribution of Phosphates in a Sewage Plant and its Receiving Waters
The purpose of this paper is to detail the distribution and quantity of soluble phosphates in an activated sludge plant, its discharge creek, and receiving reservoir. The resultant analyses and comparison of data should provide some better understanding of the fate of phosphorus in a Southwestern waterway system.
Transferrin Inheritance in the Pigeon, Columba livia
This study investigated transferrin inheritance in homing pigeons (Columba livia), using discontinuous acrylamide gel electrophoresis on rivanol treated serum.
Effects of X-irradiation on Ion Flux in Desheathed Toad Sciatic Nerves
The purpose of this thesis is to determine the effects of x-irradiation on the efflux of potassium, sodium and calcium ions from stimulated and unstimulated desheathed sciatic nerves.
Effects of n-Decenylsuccinic Acid (n-DSA) and It's Monomethyl Ester (m-MDSA) on Water and Ion Flux in Isolated Roots
The purpose of this study was (1) to measure the changes in water flux in isolated roots exposed to n-DSA and its mono-methly ester (m-MDSA) using a photometric technique in the absence of an externally applied suction and (2) to measure the flux of Na and K in similarly treated roots using a flame photometric method.
Growing Earthworms in Artificial Environments
This study is intended to investigate the artificial environment conditions that would favor the most effective propagation of the African night crawler.
The Inheritance of Serum Alkaline Phosphatase in the Pigeon (Columba livia)
The purpose of this work was to determine the manner of inheritance of serum alkaline phosphatase in the racing pigeon, (Columba livia). The evidence indicates that the electrophoretic patterns of serum alkaline phosphatase in the pigeon are inherited as codominant genes.
Parasites of the Cricket Frog, Acris Crepitans, of Denton County, Texas
The purpose of this study was threefold. The literature concerning parasites of A. crepitans was to be brought up to date. Contributions to the general body of knowledge pertaining to the parasitic fauna of host specimens of A. crepitans and specifically those found in Denton County, Texas, were to be made. Finally, specimens found parasitizing host specimens of A. crepitans were to be preserved and classified.
Rectal Temperatures of the Cotton Rat, Sigmodon Hispidus (Rodentia : Cricetidae)
This investigation has been concerned with determining the extent to which a small mammal, the cotton rat, may become acclimated to environmental temperatures, and the influence acclimation has upon a population. The study was also designed to determine if acclimation effects on a population can be seen in individual rats.
A Bacteriological Survey of a Freshwater Reservoir
In this study organisms that can be subcultured from lake water, using a prescribed procedure, limit, to an extent, the population, or portions of the population, that can be monitored. In essence, what is taking place is that a set of conditions is set forth and a study is made of the bacteria that will grow under these prescribed conditions.
The Effects of Hexadecanol on the Microbiota of Lake Hefner
It seemed desirable to investigate more fully the effect of hexadecanol on the microbial population of a reservoir. It was the purpose of this investigation to determine the effect of hexadecanol on the micro-biota of Lake Hefner, to ascertain which organisms were stimulated by hexadecanol both in the laboratory and the reservoir, and to investigate the degradation of hexadecanol by microorganisms selected from Lake Hefner.
Some Physiological Characteristics of Vitreoscilla stercoraria
The purpose of this study was to elucidate some of the physiological characteristics of V. stercoraria with regard to oxygen requirements, growth, nutritional requirements, pH effects on growth and growth factors.
Bacterial Utilization of Volatile Substances Produced by Streptomyces Lavendulae
The purpose of this investigation is to attempt to learn something of the biochemical ecology of volatile substances produced by actinomycetes.
Chronic Acceleration and Osteogenesis
The effect of excess gravity on bone-forming elements of the growing perichondrial shaft of embryonic chicks was investigated through the use of the transmission electron microscope and various cytochemical techniques.
Experimental Trichinosis in Birds
This work concerns itself with essentially four experiments: (1) the cecum-injective-infection experiment; (2) the anus-injective-infection experiment; (3) the mouth ingestive-infection with larvae, and (4) the mouth ingestive-infection with the flesh of infected rats.
Comparative Ultrastructural Study between Young and Adult forms of Trypanosoma Lewisi
The purpose of this study was to examine the ultrastructure of both young (dividing form) and adult (stationary form) of Trypanosoma lewisi. Changes observed between the two forms of the organism were related directly to data obtained from previous comparative biochemical studies conducted on these forms of Trypanosoma lewisi.
Isolation and Partial Characterization of a Bacterium Which Gives Off Filtrable Cells
The present study was on the isolation of a bacterium capable of producing filtrable forms which passed through the 0.45µ filter membrane and regenerated the parental form; the testing of the true filtrability of the isolate; the relationship between growth of the isolate and appearance of filtrability; partial characterization of the isolate and visualization of the elements that passed through the membrane filter with electron microscopy and shadow casting technique.
Studies of Odor-Producing Actinomycete Response to Selected Geosmin Concentrations
The purpose of this investigation was to explore how geosmin, an odorous compound produced by certain algae and actinomycetes, may affect the growth of a selected, odor producing actinomycete of the genus Streptomyces.
Influence of Sublethal Pesticide Levels of Repiratory Activity of Selected Aquatic Animals
The respiratory activity of three aquatic animals selected from different pollution index classifications is examined in the presence of sublethal concentrations of Dibrom, a commonly used, broad-spectrum, organophosphate insecticide.
Studies on the Morphology and Biology of Cotton Rats (Sigmodon hispidus) from Northern Mexico to Southern Nebraska
This investigation was designed to evaluate the need for retaining both Sigmodon hispidus texianus and Sigmodon hispidus berlandieri as subspecific designations. An attempt was made to demonstrate bioclimatic variation and reproductive seasonality in cotton rats. The validity of applying the results of isolated studies of cotton rat populations to the species as a whole was examined.
Phosphatides of Atypical Mycobacteria
The purpose of this investigation was to extract, separate, partially characterize and compare the individual phospholipids of the atypical mycobacteria.
Heat Resistance in Vegetative Cells and Cysts of Azotobacter
The purpose of the current study is to determine something of the nature of the heat resistance in Azotobacter, if in fact this is found to exist. An attempt is made to determine the specific physiological state associated with heat resistance as well as to resolve this resistance quantitatively.
Isolation, Purification, and Characterization of Aldolase from Human Heart
Aldolase from human heart has been purified 128-fold to a final specific activity of 11.52 units per mg. The purification procedure employed column chromatography on phosphocellulose.
Observations on the Life History of the Brown Spider, Loxosceles Reclusa Gertsch and Muliak
This research was undertaken primarily to further elucidate the life history of this medically important spider. Special attention was given to rearing experimental spiders under as near-natural environmental conditions as possible.
Pleomorphism in Selected Genera of Algae
It is the purpose of this study to ascertain what environmental factors might cause morphological changes exhibited by certain algae, also to determine if this variation in morphology is vegetative, reproductive, or artifactual in nature, and to show what effects these changes in morpohology might have on classification of the organisms in question.
Some Effects of X-Irradiaion on the Adrenal Response to Hypothalamic Stimulation in Rats
Exactly where in the hypothalamus is the adrenal-pituitary response to X-irradiation "triggered" or initiated? Moreover, does ionizing radiation act directly on specific centers in the brain or does it act indirectly via the production of some humoral agents? Finally, what role does the hypothalamus play in the radiation-syndrome? The purpose of the present study was to attempt to answer these questions by determining the effects of two stressor agents, X-irradiation and electrical stimulation applied either singly or together, on the activity of the adrenal-pituitary axis. The parameters measured were changes in plasma corticosterone, in circulating eosinopihils, and in adrenal gland weight.
Serological Characteristics of Morphologically and Biochemically Similar Streptomyces Species
It is the purpose of this investigation to test for serological characteristics of six Streptomyces species which exhibit identical and/or very closely similar morphological and biochemical characteristics.
The Production of Fragile Cysts by an Aberrant Strain of Azotobacter Chroococcum Isolated from Soil
The purpose of this study is to determine if a strain of Azotobacter chroococcum isolated from the soil in northern Louisiana produces cysts which are as resistant to deleterious agents as those produced by previously reported strains os Azotobacter.
A Screening of Fungi for Metabolites Inhibitory to the Growth of Bloom-Forming Blue-Green Algae
Since many approaches to dealing with algal blooms are inefficient, expensive, or harmful, it was concluded that a biologically-synthesized chemical agent, specifically inhibitory to pre-bloom algal cells, might prove helpful in controlling algal blooms. Fungi were chosen as the biological entities to investigate for such a chemical.