UNT Libraries - 128 Matching Results

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Aryl Hydrocarbon Hydroxylase and Sixteen Alpha Hydroxylase in Cultured Human Lymphocytes

Description: Cultured human lymphocytes may be assayed for aryl hydrocarbon hydroxylase (AHH) in whole cell preparations. The optimum assay conditions are pH 8.5, and 1.5 mM Mg++. The reaction is linear with time and cell number, and is inhibited by CO. Estradiol may inhibit induction of AHH by 3-methylcholanthrene, but is a poor competitor for the enzyme. A Caucasian population was assayed for AHH activity. The distribution was lognormal; no difference was found in cultured cells from males and females or smokers and nonsmokers. Cells from relatives of lung cancer patients showed higher activity. An American Indian population showed no difference from the Caucasian population in enzyme level. No linkage was found between AHH and 16a-hydroxylase.
Date: December 1975
Creator: Coomes, Marguerite L.

An Assay Method for Determining Extra-Cellular Lipases from Pseudomonas aeruginosa

Description: The applicability of an isotopically labelled assay system to determine the lipase production in Pseudomonas aeruginosa was evaluated. Supernatant from cultures of Pseudomonas aeruginosa grown in a medium containing olive oil was incubated with a substrate containing labelled trioleate. Fatty acids were isolated by means of a liquid-liquid partition system. Enzyme activity was determined by measuring the amounts of free fatty acid by liquid scintillation counting. Findings indicate that the isotopicallylabelled, liquid-liquid partitioning assay is reliable, sensitive and adaptable to rapid assay conditions. It was also determined that different strains of Pseudomonas aeruginosa produce varying amounts of lipase. Partial purification of supernatant by gel filtration produced two protein peaks showing enzymatic activity.
Date: May 1978
Creator: Christensen, John N.

The Autecology of Celtis Laevigata in Flood Plain Forests of Denton County, Texas

Description: This thesis describes the present nature of one facet of some of the flood plain forest stands in Denton County, Texas. The specific purpose was to demonstrate the presence or absence of difference between the Celtis laevigata (commonly known as the hackberry, southern hackberry or sugarberry) populations in stands on Denton Creek and Elm Fork of the Trinity River.
Date: January 1970
Creator: Hander, Lecil B.

Biochemical Genetics of Certain Species of the Blackbird Family Icteridae

Description: Starch gel electrophoresis was used to compare 14 proteins encoded by 15 loci for seven species of the family Icteridae. A close genetic relationship among these species was classified into three groups. The Agelaiine group contained Agelaius phoeniceus, Sturnella magna, and S. neglecta. The Quiscaline group contained Euphagus cyanocephalus, Cassidix mexicanus, and Quiscalus quiscula. Molothrus ater, the most divergent, was placed in a separate group. Divergence times for the seven species were compared to the literature. Heterozygosity of the seven populations of the two species of Sturnella were compared to determine factors influencing their divergence. Two factors proposed were heterosis in S. neglecta and possible hybridization between S. neglect and S. magna.
Date: December 1974
Creator: Smith, Jackson Kelly

Biological Nitrogen Fixation in Two Southwestern Reservoirs

Description: This investigation has determined the presence of biological nitrogen fixation in two reservoirs in the southwestern United States: Lake Arlington and Lake Ray Hubbard. Subsequent tests have gathered baseline data on the effects of various biological, chemical, and physical parameters on in situ nitrogen fixation in these reservoirs. Of specific importance is the relationship between nitrogen fixation arid occasional blooms of blue-green algae which produce such problems as testes and odors in these water-supply impoundments.
Date: August 1973
Creator: Lawley, Gary G.

Biosystematic Study of a Desmodium Complex

Description: An examination of the Desmodium canescens complex (D. canescens; D. tweedyi; D. illinoense) has resulted in the delimitation of a previously unreported alliance between D. canescens and D. tweedyi. The following points support this view: (a) morphological data taken from herbarium and garden specimens indicate that for many characters, the mean values of D. canescens and D. tweedy are not significantly different (b) breeding experiments have shown that artificial interspecific hybridization is possible between D. canescens and D. tweedyi (c) cytological studies have shown that D. canescens and D. tweedyi have a base number of x = 11, while D. illinoense has a base number of x = 10. A new combination is suggested: Desmodium canescens var. tweedyi (Britt.) Williams.
Date: December 1977
Creator: Williams, John G., 1949-

Capillary Permeability to Narrow-Range Macromolecular Dextrans at Normal and Hypobaric Pressures

Description: In view of its varied concepts and interpretations, and because of the discrepancies produced by the previous utilization of polydispersed dextrans, a study using extremely narrow-range molecular weight dextran fractions was initiated to reevaluate and consolidate some of the aspects of capillary permeability. A portion of the study was performed under decreased barometric pressure in order to clarify further some of the mechanisms involved in particulate transfer across the capillary endothelial membranes. Gel filtration procedures augmented the study as an assessment of the polydispersity effects of the dextrans employed.
Date: December 1972
Creator: Norris, John Anthony

Carbon Flux in Reservoir Sediments

Description: The central objective of the study was to fractionate sedimenting organic materials according to their source (allochthonous or autochthonous) and ultimately to determine the degree of biodegradability of contributions from either source with particular reference to activities at the mud-water interface.
Date: May 1973
Creator: Newton, Charles Eugene

Cigarette Residues Affect Steroidogenesis in Cultured Y-1 Mouse Adrenal Tumor Cells

Description: This study (1) quantitatively compared steroid production in cultured Y-l mouse adrenal tumor cells exposed to Camel and Carlton-smoke derived residues, and (2) localized the effects in the cell. Basal steroid production was increased by Camel residues but not by Carlton, while ACTH stimulation was interfered with by both residues. Camel basal stimulation was comparable to that of cAMP, and was abolished by Cytochalasin D. The stimulation was also comparable to that of cholera toxin, which activates adenyl cyclase. Results indicate that residue components dissolve in the membrane stimulating adenyl cyclase at a point similar to or before that utilized by cholera toxin for its stimulating effect.
Date: December 1979
Creator: Morris, Paula D.

Comparative Chemistry of Thermally Stressed North Lake and Its Water Source, Elm Fork Trinity River

Description: To better understand abiotic dynamics in Southern reservoirs receiving heated effluents, water was analyzed before and after impoundment in 330 ha North Lake. Macronutrients, metals, and chlorinated hydrocarbons were measured. Concentrations of nutrients and metals in sediments were quantified in this 2 yr study. River water prior to impoundment contained 16 times more total phosphorus, and supported 23 times more Selenastrum capricornutum cells in an algal assay than reservoir water. The reservoir has essentially no drainage and since evaporation is high, the concentrations of many dissolved solids have increased since the reservoir was filled in 1958. North Lake is now phosphorus limited. Apparently altered chemical equilibria have caused precipitation or adsorption of phosphorus with calcium and iron.
Date: December 1976
Creator: Sams, Barry L.

Comparative Ultrastructural Study between Young and Adult forms of Trypanosoma Lewisi

Description: 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.
Date: August 1973
Creator: Abdul-Salam, Jasem M.

Degradation of Homologous Polymerized Deoxyribonucleic Acid by Azotobacter Vinelandii ATCC 12837

Description: The purpose of this study was twofold. The first was to isolate, purify, and characterize the deoxyribonucleic acid (DNA) of Azotobacter vinelandii ATCO 12837. The second was to determine if there was irreversible binding of homologous 32P labeled DNA to recipient A. vinelandii cells.
Date: August 1972
Creator: Barnes, Wayne Riley

Differences in Protein Constituents of Some Azotobacter Species

Description: This study used polyacrylamide gel electrophoresis to study the acid-phenol soluble proteins of five strains (A. vinelandii 12837, A. vinelandii 0, A. chroococcum 8004, A. macrocytogenes 8702, A. tumefaciens) of bacteria grown on Burk's nitrogen-free media, Trypticase Soy Broth, and 0.3% butanol medium. The results showed that the protein patterns can be used for the identification and possibly the taxonomic classification of the Azotobacter. The change of phenotype of the bacteria in different media followed the change of protein quantity and quality. There was no absolute similarity between any two of the species studied and this suggests a genetically heterogenous group of organisms while the amount of common proteins suggests close genetic relationships. Further studies are necessary to confirm the status of A. tumefaciens.
Date: August 1975
Creator: Hsu, Li-Chu Yao

Diphenyloxazole Metabolism by Aryl Hydrocarbon Hydroxylase

Description: 2,5-Diphenyloxazole (PPO) was tested as a potential alternate inducer for the aryl hydrocarbon hydroxylase (AHH) system. Its apparent lack. of carcinogenicity and toxicity provide a possible system for investigation of enzyme systems related to chemical carcinogenesis without exposure of the researcher to potent carcinogenic compounds. These studies found PPO to be an inducer of AHH in cultured human lymphocytes. When PPO was utilized as a substrate for the AHH assay system, the major metabolites produced were strongly fluorescent. A simple fluorometric assay was developed which employed PPO as the substrate and which measured constitutive activity more efficiently than similar assays using benzo(a)pyrene as the substrate. Quantitation of both basal and induced lymphocyte AHH metabolism of PPO may be applicable to human population studies and may provide a tool to determine possible genetic variables with respect to carcinogen metabolism related to cancer risk.
Date: December 1976
Creator: Abreu, Mary E.

Distribution, Abundance, and Food Habits of Larval Fish in a Cooling Reservoir

Description: Analysis of larval fish collected at four stations in a 330-ha cooling reservoir indicated Dorosoma spp. were most numerous at all stations, followed by Lepomis spp. and Percina Macrolepida. Largest numbers and greatest diversity of larval fish were found at the station least affected by thermal effluent; the mid-lake station provided the smallest numbers and least diversity. The two warmwater stations were intermediate, with similar numbers and diversity. Diversity and abundance of zooplankton between stations were similar to those of fish. The most abundant zooplankter (Bosmina) was generally selected against by Dorosoma, Lepomis and Micropterus spp. larvae except when the larvae were quite small ((10mm). Cyclopoid copepods were most often selected by all larvae.
Date: December 1978
Creator: Mitterer, Lana Gayle

The Distribution of Pathogenic Pseudomonas aeruginosa in Sewage

Description: The purpose of this study was to extend our understanding of the ecological relationships of P. aeruginosa by investigating the differences or similarities between the strains of this organism found in sewage and those found as pathogens in human infections. This research was approached by comparing the serological types of P. aeruginosa isolated from sewage contaminated waters in Argentina (South America) to those isolated from sewage contaminated waters in Texas. They were typed with sera obtained using P. aeruginosa isolated from human infections. The data obtained revealed that bacteria isolated from sewage in Texas and from soil and water in Argentina are antigenically similar to those isolated from human infections.
Date: May 1974
Creator: Labay, Joseph Edward

Distribution, Size, Condition, and Food Habits of Selected Fishes in a Reservoir Receiving Heated Effluent from a Power Plant

Description: This study was undertaken in order to provide further insight into the effects of artificial heating on the fisheries of a small reservoir in the Southwest. The following specific objectives were established: (1) to map the reservoir for the distribution of heated water, (2) to determine the distribution of selected species of sports, rough, and forage fish in areas affected by the effluent and in areas not affected, (3) to compare size and condition of selected species of fish from areas affected by the effluent to size and condition of fish from areas not affected, and (4) to compare food habits of channel catfish in areas affected by the effluent to the food habits of channel catfish in areas not affected.
Date: December 1972
Creator: McNeely, David L.