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 Department: Department of Biology
 Collection: UNT Theses and Dissertations
A Comparative Study of the D Cells of Certain Mammalian Islets of Langerhans

A Comparative Study of the D Cells of Certain Mammalian Islets of Langerhans

Date: August 1954
Creator: O'Brien, Larry Joe
Description: The purpose of this study is to describe and compare the D cells of the islets of Langerhans in six different species of mammals.
Contributing Partner: UNT Libraries
Comparative Ultrastructural Study between Young and Adult forms of Trypanosoma Lewisi

Comparative Ultrastructural Study between Young and Adult forms of Trypanosoma Lewisi

Date: August 1973
Creator: Abdul-Salam, Jasem M.
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.
Contributing Partner: UNT Libraries
A Comparison of Predicted and Actual Trophic Status of Lake Ray Roberts, TX Based on Chlorophyll A

A Comparison of Predicted and Actual Trophic Status of Lake Ray Roberts, TX Based on Chlorophyll A

Date: May 1999
Creator: Lytle, Lili Lisa
Description: Two years before impoundment, the trophic status of Lake Ray Roberts was predicted by applying the total phosphorus input into the Organization for Economic Cooperation and Development (OECD) eutrophication model. Predicted mean summer epilimnetic (MSE) chlorophyll a of Elm Fork arm, Isle duBois arm and Main Body were in the eutrophic category of the OECD model. Observed MSE chlorophyll a two years after impoundment of Elm Fork arm, Isle duBois and Main Body had not reached their predicted means and were at the mesotrophic-eutrophic boundary of the OECD model. Six years after impoundment, observed MSE chlorophyll a for Main Body, was closer to its predicted mean and in the eutrophic category of the OECD model. Six years after impoundment, Elm Fork arm was the most productive area of Lake Ray Roberts. Observed means of chlorophyll a, total phosphates, suspended solids and turbidity were often highest in the Elm Fork arm. Wastewater effluent from Gainesville and Valley View, TX, had an impact on productivity in Elm Fork arm.
Contributing Partner: UNT Libraries
A Comparison of Specificity of Passive Transfer of Chemical Contact Hypersensitivity Following Different Methods of Sensitization

A Comparison of Specificity of Passive Transfer of Chemical Contact Hypersensitivity Following Different Methods of Sensitization

Date: June 1967
Creator: Foster, Terry L.
Description: This thesis compares the specificity of passive transfer of chemical contact hypersensitivity following various methods of sensitization.
Contributing Partner: UNT Libraries
A Comparison of the Carbon Dioxide and Oxygen Rate of Change Methods for Measuring Primary Productivity

A Comparison of the Carbon Dioxide and Oxygen Rate of Change Methods for Measuring Primary Productivity

Date: May 1969
Creator: Trotter, Dennis M.
Description: The purpose of this study was to demonstrate the variability of oxygen and carbon dioxide rate of change methods for measuring primary productivity and respiration in an aquatic environment.
Contributing Partner: UNT Libraries
Composition and Distribution of the Vegetation in Farm Pastures in Denton County, Texas

Composition and Distribution of the Vegetation in Farm Pastures in Denton County, Texas

Date: 1946
Creator: Parker, Robert S.
Description: This investigation has for its aim the determination and the evaluation of the vegetational composition in certain farm pastures in Denton County, Texas.
Contributing Partner: UNT Libraries
Construction of a  Pseudomonas aeruginosa Dihydroorotase Mutant and the Discovery of a Novel Link between Pyrimidine Biosynthetic Intermediates and the Ability to Produce Virulence Factors

Construction of a Pseudomonas aeruginosa Dihydroorotase Mutant and the Discovery of a Novel Link between Pyrimidine Biosynthetic Intermediates and the Ability to Produce Virulence Factors

Date: August 2003
Creator: Brichta, Dayna Michelle
Description: The ability to synthesize pyrimidine nucleotides is essential for most organisms. Pyrimidines are required for RNA and DNA synthesis, as well as cell wall synthesis and the metabolism of certain carbohydrates. Recent findings, however, indicate that the pyrimidine biosynthetic pathway and its intermediates maybe more important for bacterial metabolism than originally thought. Maksimova et al., 1994, reported that a P. putida M, pyrimidine auxotroph in the third step of the pathway, dihydroorotase (DHOase), failed to produce the siderophore pyoverdin. We created a PAO1 DHOase pyrimidine auxotroph to determine if this was also true for P. aeruginosa. Creation of this mutant was a two-step process, as P. aeruginosa has two pyrC genes (pyrC and pyrC2), both of which encode active DHOase enzymes. The pyrC gene was inactivated by gene replacement with a truncated form of the gene. Next, the pyrC2 gene was insertionally inactivated with the aacC1 gentamicin resistance gene, isolated from pCGMW. The resulting pyrimidine auxotroph produced significantly less pyoverdin than did the wild type. In addition, the mutant produced 40% less of the phenazine antibiotic, pyocyanin, than did the wild type. As both of these compounds have been reported to be vital to the virulence response of P. aeruginosa, ...
Contributing Partner: UNT Libraries
Correlation of C'4 and Antibody Response to Antigen-Adjuvant Injections

Correlation of C'4 and Antibody Response to Antigen-Adjuvant Injections

Date: June 1962
Creator: Foster, Billy G.
Description: This paper will attempt to determine whether the increased C'4 previously shown following antigen and adjuvant injection could be correlated to antibody increase following antigen injection.
Contributing Partner: UNT Libraries
A correlation of the Edaphic Factors with the Vegetation of the Woodbine sands, Denton County, Texas

A correlation of the Edaphic Factors with the Vegetation of the Woodbine sands, Denton County, Texas

Date: August 1936
Creator: Graham, H. L.
Description: The purpose of this study was to correlate the Vegetation of the Woodbine Sands with the edaphic factors. In the laboratory an analysis of the edephic factors was made of the twenty-two soil types collected from the three formations. The results of these and other analysis are shown in tables and graphs. The results indicate that the vegetational cover of an area that is uniform in its origin and in its resident soil factors is determined by the edaphic factors present.
Contributing Partner: UNT Libraries
A Correlation of the Habitat Factors with the Quantity of Bacterial Colonies as Observed by the Direct Microscopic Method on Twenty Soils of Denton County, Texas

A Correlation of the Habitat Factors with the Quantity of Bacterial Colonies as Observed by the Direct Microscopic Method on Twenty Soils of Denton County, Texas

Date: August 1937
Creator: Roach, Cornelia Ann
Description: The aim of this study is to determine what factors are most important in controlling the number of bacterial colonies found in twent represntative Denton County (Texas) soils during the growing season.
Contributing Partner: UNT Libraries