UNT Theses and Dissertations - 25 Matching Results

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L-asparaginase II Production by Escherichia coli

Description: Growth of Escherichia coli A-l under aerobic conditions in an enriched medium with a total amount of 0.2 per cent glucose was biphasic and asparaginase II activity was detected after depletion of ammonia from the growth medium in the second phase of growth. Glucose was exhausted two hours before ammonia and three hours before asparaginase II activity was detected. The concentration of 3',5'-cyclic adenosine monophosphate was found to fluctuate when the dissolved oxygen in the medium reached a l… more
Date: May 1985
Creator: Johnson, Terrance L. (Terrance Lewyne), 1950-
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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The Reproductive Consequences of Carriers of Methylenebisacrylamide-Induced Balanced Reciprocal Translocations in Mus Musculus

Description: N,N'-methylenebisacrylamide (MBA) was studied because of its effectiveness in inducing heritable translocations in germ cells of male mice. The health impact of translocations was studied through anatomical analysis of the progeny of semisterile translocation carriers. As expected, the semisterility of translocation carriers resulted primarily from embryonic death during periimplantation stages due to unbalanced chromosome sperm segregants. Among conceptuses that survived to mid- and late-gesta… more
Date: May 1989
Creator: Kile, Joanna L. (Joanna Le)
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Characterization of the OCT Plasmid-Encoded Mercury Resistance Genetic Locus in Pseudomonas putida

Description: A 17.1 Kb genetic element encoding for mercury resistance (OCT-Hg^r) was shown to translocate from its original location on the OCT plasmid to the resistance plasmid, RPl, in Pseudomonas putida. Analysis of RPl-Hg^r recombinant plasmids revealed that insertion of mercury resistance genes into RPl could occur at a variety of sites, with all recombinants having common EcoRI restriction fragments of 9.4, 3.8, 2.3, and 1.6 Kb, derived from the insertion. Hybridization analysis suggested the existen… more
Date: May 1989
Creator: Armbruster, Steven C. (Steven Christopher)
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Partner: UNT Libraries
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An Evaluation of the Short-Term Embryo-Larval and Seven-Day Larval Test Methods for Estimating Chronic Toxicity of Zinc to the Fathead Minnow (Pimephales promelas)

Description: Chronic toxicity of zinc to Pimephales promelas was estimated by conducting replicate static and static-renewal short-term embryo-larval tests and static-renewal seven-day larval tests. The two test methods were highly reproducible. Daily renewal of test solutions had little effect on the toxicity of zinc, however, the stage of development at which exposure was initiated affected the sensitivity of the toxic endpoints measured. The most sensitive and reproducible endpoint in the embryo-larval t… more
Date: May 1987
Creator: Stewart, Susan Michels
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Partner: UNT Libraries
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Predicting the Site-Specific Bioavailability of Zinc Using the Indicator Species Procedure: A Case Study

Description: National Water Quality Criteria intended to protect aquatic life and their uses from the adverse effects of pollutants may not be appropriate due to site-specific factors that alter chemical bioavailability. The Indicator Species Procedure may be used to derive site-specific criteria in order to account for differences in site-specific bioavailability. This procedure was implemented using zinc for three chemically different site (river) waters. The purpose of this study was to quantify the bioa… more
Date: May 1987
Creator: Parkerton, Thomas F.
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Partner: UNT Libraries
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Genetic Variation in a Population of the Plains Woodrat Neotoma micropus

Description: Neotoma micropus from Jack County, Texas, were studied over a 9-month period. Loci from blood and saliva were used to determine genetic variation within the population. Deviations from Hardy-Weinberg equilibrium were found at one locus. The average temporal F over all seven loci was 0.040. Genetic structuring was subtle, fluctuated on a seasonal basis, and was due to differential migration or predation on genotypes. Heterozygotes tended to move more than homozygotes, and a greater proportion of… more
Date: August 1988
Creator: Stewart, John E. B. (John Edward Bakos)
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Partner: UNT Libraries
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Adenylate Energy Charge Determinations of Soil Bacteria Grown in Soil Extract Medium

Description: The adenylate energy charge values of twenty bacteria isolated from soil and cultured in a medium consisting of soil and distilled water were determined by the luciferin-luciferase bioluminescense method. The purpose of this study was to examine the growth and energy charge values of these organisms in soil extract medium, and to determine what effect the addition of glucose has on their energy charge values. Three of the organisms employed in this study showed energy charge values similar to t… more
Date: August 1988
Creator: Rodriguez, Luis A. (Luis Antonio)
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Partner: UNT Libraries
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A New LC Column for the Separation and the Quantitation of Nucleotides

Description: A new column, Dionex AS4A, (polystyrenedivinylbenzene matrix) used for the separation of ribonucleotides and deoxyribonucleotides for the first time, and previously used for ion analysis was found superior to conventional silica columns because it separates ribonucleotides and deoxyribonucleotides. Resolution of dGTP was not possible with the Dionex column and CTP and GDP often co-eluted. Using conventional silica columns, monophosphates separated from diphosphates and diphosphates from triphos… more
Date: December 1987
Creator: Brock, Patricia C. (Patricia Charlene)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Effects of Long-Term Moderate Ethanol Intake on the Stress Response in Rats

Description: The effect of ethanol on the stress response in rats was examined. Experimental animals were given 0.25 ml of 28 percent ethanol or 0.25 ml of water orally once a day, five days a week, for a period of twelve months and were then subjected to fifteen minute cold stress. Corticosterone levels in ethanol-treated males following stress were significantly lower (22 percent) than in the sham group. Adrenal weights in sham-treated females were significantly higher (15 percent) than in the ethanol gro… more
Date: December 1984
Creator: Williams, Judy L. (Judy Lee)
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Partner: UNT Libraries
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Biological Control of the Red Imported Fire Ant by the Entomopathogenic Nematode, Steinernema Carpocapsae (Weiser)

Description: Field trials were conducted in 1988 to evaluate the effectiveness of Steinernema (=Neoaplectana) carpocapsae (Weiser) in controlling the fire ant. Infective juveniles (IJ) of the nematode were applied as drench on 235 and 422 mounds, respectively for 2-month summer and 6-week fall evaluation periods. In comparative trials, amidinohydrazone (Amdro) was applied to 249 (summer) and 65 (fall) active mounds, with 245 (summer) and 78 (fall) untreated active as controls. Nematode treatments resulted i… more
Date: August 1989
Creator: Morris, John R. (John Robert), 1949-
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Partner: UNT Libraries
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Brain Activity in Rats Exposed to Short-Term External Electrical Fields

Description: The effects of external electric fields (EEF) on brain activity in anesthetized rats were studied. The field strengths used, 9 kV/m and 5 kV/m, both D.C. and A.C. (60Hz) were in the range of those measured beneath current overhead transmission lines. Brain activity was monitored from surface electrodes and from electrodes stereotaxically implanted in the posterior-lateral portion of the hypothalamus. It was found that 9 kV/m and 5 kV/m EEF's both D.C. and A.C. brought about statistically signif… more
Date: May 1985
Creator: Hines, Gregory M. (Gregory Manuel)
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Partner: UNT Libraries
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Nutritional Requirements of Corynebacterium poinsettiae

Description: In a minimal medium supplemented with glucose and yeast extract, the optimum pH for the growth of C. poinsettias was found to be 7.5. The organism requires thiamine, biotin, and pantothenic acid for growth. No absolute requirement was found for any amino acid, purine or pyrimidine although an amino acid mixture was stimulatory. Casamino acids could be substituted for the synthetic amino acid mixture. Yeast extract provided an additional factor(s) necessary for maximal growth. The results sugges… more
Date: December 1983
Creator: Hooshdaran, Farideh
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Partner: UNT Libraries
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Plasma Ion Concentrations in Selected Fishes from Four North Central Texas Reservoirs with Different Salinities

Description: Mean salinity concentrations in the four reservoirs (Moss, Ray Hubbard, Texoma and Possum Kingdom) ranged from 0.2 ppt in Moss Lake to 2.01 ppt in Possum Kingdom Lake. Reservoir sodium and chloride concentrations were hypotonic to hypertonic to plasma levels in all species. Interspecific differences were seen in ionic concentrations within each reservoir. Total osmotic and sodium concentrations in carp, Cyprinus carpio, were correlated to their concentrations in the reservoirs. No such relation… more
Date: December 1983
Creator: Del Regno, Kenneth J. (Kenneth Joseph)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Properties of Normal Rat Kidney Cells Transformed by a Temperature-Sensitive Mutant (LA31) of Rous Sarcoma Virus

Description: The basis of this investigation is to characterize growth property differences in normal versus virally transformed cells. Using a temperature-sensitive mutant of Rous sarcoma virus, the cells' transformation state is regulated by the growth temperature; at 33°C the cells are transformed, while at 39°C the cells have normal characteristics. The morphology of NRK cells is elongated and fibroblastic; when transformed the cells are rounded. Normal cells grow to a monolayer and stop, while transfor… more
Date: August 1983
Creator: Connolly, John R. (John Robert)
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Partner: UNT Libraries
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Ethylbromo Acetate as an Olfactory Probe

Description: Olfactory transduction mechanisms are best studied when specific blocking agents are available with which to modify cellular responses to odorant stimulation. This study is an electrophysiological investigation of functional group-specific olfactory acceptor mechanisms using ethylbromo acetate (EtBrAc), a World War I war gas which inhibits olfactory responses to odorant stimulation. The major findings of this investigation show that (1) vaporous EtBrAc is found to be a quick and effective inhib… more
Date: August 1980
Creator: McClure, Fred Leland
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Studies on the Purification and Phosphorylation of Phosphofructokinase from Ascaris suum

Description: A new procedure has been developed to concentrate the phosphofructokinase from muscle of Ascaris suum with minimum loss of activity. By utilizing this method, 50 ml fraction was concentrated to a final volume of 3 ml in about 1.5 h without loss in enzyme activity. The concentrated enzyme had a specific activity of 64 units per mg. Ascaris muscle-cuticle was incubated in 50 1M solutions of either acetylcholine, serotonin, y-aminobutyric acid, levamisole, or saline alone. Phosphate analysis of th… more
Date: August 1983
Creator: Kaeini, Mohammad R. (Mohammad Reza)
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Partner: UNT Libraries
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Aquatic Vegetation Nutrient Budgets and Sedimentation in a Southwestern Reservoir

Description: During four growing seasons, aquatic vascular plant production and distribution were studied in Pat Mayse Lake, Texas, a 2425 hectare oligo-mesotrophic reservoir. The dominant macrophyte population was Myriophyllum spicatum L. Growth rates and regrowth rates of mechanically harvested Myriophyllum beds were found to be dissimilar. Based on estimates of watermilfoil nutrient content, there were insufficient nutrients in the entire population to alter the trophic status of this reservoir should al… more
Date: May 1986
Creator: Clifford, Philip A. (Philip Alan)
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Effects of N⁶,O²'-Dibutyryl Cyclic Adenosine 3' ,5' Monophosphate on Transformation of Rat Kidney Cells and Chick Embryo Fibroblasts by Wild-Type and Temperature-Sensitive Rous Sarcoma Virus

Description: N^6,O^2' -Dibutyryl cyclic adenosine 3',5'-monophosphate (Bt_2cAMP) was investigated for its effects on various tissue culture cells infected with temperature-sensitive (ts) mutant, LA31 and Bratislava 77 (B77), a wild-type Rous sarcoma virus. Specifically, known parameters of transformation were investigated and a possible site of action has been tenably proposed. The drug Bt_2cAMP was found to have little effect on the transformation related properties of primary chick embryo fibroblasts (CEF… more
Date: December 1983
Creator: Marshall, David A. (David Allen)
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Isolation and Partial Characterization of Pigment Mutants of Corynebacterium poinsettie ATCC 9682

Description: Carotenoid pigments were extracted from Corynebacteriuma poinsettiae (wild type) ATCC 9682, and from 108 mutants obtained by exposure of a streptomycin resistant strain of C. poinsettiae to ultra-violet light irradiation and N-methyl- N'-nitro-N-nitrosoguanidine. The pigments were characterized by their absorption maxima, Rf-values, and partition ratios in petroleum ether and methanol. Thin layer chromatography was used to compare pigments of the wild type with those of the mutants. Possible bi… more
Date: August 1980
Creator: Wariso, Benjamin A.
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Effects of Pulp and Paper Mill Effluent on Stream Primary Productivity in the Lower Sulphur River, Texas

Description: Responses of periphyton and phytoplankton productivity in the lower Sulphur River (Texas-Arkansas) to bleach-kraft mill effluent (BKME) were monitored using in situ ¹⁴C incubation. Carbon assimilation rates measured downstream of mill discharge were substantially reduced from upstream levels. Periphyton and phytoplankton chlorophyll a concentrations remained relatively unchanged by the presence of BKME. Periphyton ash-free dry weight increased near the mill outfall, but decreased further downst… more
Date: August 1982
Creator: Davis, Terrence Marvin
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Failure of Azotobacter Vinelandii to Fix Nitrogen in Soil

Description: It was found that Azotobacter vinelandii grown in a dialyzed soil medium did not fix nitrogen and had a much lower rate of respiration than when grown in Burk's nitrogen-free medium. When para-hydroxybenzoic acid served as the added oxidizable organic carbon source in dialyzed soil medium, the azotobacter grown in it were found to be unable to fix nitrogen. On the other hand, A. vinelandii fixed nitrogen when grown in soil supplemented with glucose. It was concluded that natural conditions in t… more
Date: August 1983
Creator: Taeed-Kashani, Taraneh
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A Computer Assisted Micro-Dye Uptake Interferon Assay System

Description: A new rapid computer assisted micro-titer plate interferon assay system was developed and characterized for use in high capacity clinical and research applications. The biological aspect of the assay was a modification of the assay methods of Finter, Armstrong and McManus. It was an application of spectrophotometric quantification of the reduction of viral cytopathic effect (CPE) as reflected by neutral red dye uptake by viable cells. A computer program was developed for the extrapolation of ra… more
Date: August 1981
Creator: Duvall, John C.
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The Determination of Uptake and Depuration Rate Kinetics and Bioconcentration Factor of Naphthalene and Lindane in Bluegill Sunfish, Lepomis macrochirus

Description: Bluegill were exposed to 3 and 30 pg/L lindane and 20 and 200 pg/L naphthalene to determine uptake rate constants, K1 depuration rate constants, K2, and bioconcentration factors, BCF. Correlations were determined between lipid normalized and non-lipid normalized BCFs, and between observed Kl, K2 and BCFs and predicted values. The K1 values for both chemicals and concentrations were similar. The K2 values were different (1.04 day~1, 0.46 day 1). Naphthalene was more rapid. BCFs for lindane (315)… more
Date: August 1981
Creator: DeFoer, Marguerite J.
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Determination of Biotransformation and Biodegradation Rate Constants for Naphthalene, Lindane and Phenol

Description: Biotransformation and biodegradation rate constants were determined for naphthalene, lindane, and phenol in water samples from three different sources. Rate constants produced from monitoring disappearance of the parent chemical (biotransformation) were compared to those obtained from mineralization of the chemical (ultimate biodegradation) by ¹⁴CO₂ evolution as well as acidification of the residual ¹⁴C-labeled compound (primary biodegradation). Rate constants were statistically different for t… more
Date: December 1981
Creator: Crawford, Judith Chase
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Partner: UNT Libraries
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