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  Partner: UNT Libraries
 Degree Discipline: Biology
 Collection: UNT Theses and Dissertations
The Effect of Geosmin on the Growth of Bacillus cereus

The Effect of Geosmin on the Growth of Bacillus cereus

Date: August 1972
Creator: Barnes, Randall D.
Description: The purpose of this study was to determine the effect of varying concentrations of geosmin on the growth of Bacillus cereus.
Contributing Partner: UNT Libraries
Degradation of Homologous Polymerized Deoxyribonucleic Acid by Azotobacter Vinelandii ATCC 12837

Degradation of Homologous Polymerized Deoxyribonucleic Acid by Azotobacter Vinelandii ATCC 12837

Date: August 1972
Creator: Barnes, Wayne Riley
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.
Contributing Partner: UNT Libraries
Comparison of Aspartate Transcarbamoylase and Pyrimidine Salvage in Sporosarcina urea, Sprolactobacillus inulinus, Lactobacillus fermentum, and Micrococcus luteus

Comparison of Aspartate Transcarbamoylase and Pyrimidine Salvage in Sporosarcina urea, Sprolactobacillus inulinus, Lactobacillus fermentum, and Micrococcus luteus

Date: August 1994
Creator: Barron, Vincent N. (Vincent Neal)
Description: The enzyme that catalyzes the committed step in pyrimidine biosynthesis, aspartate transcarbamoylase, has been compared in selected endospore-forming organisms and in morphologically similar control organisms. The ATCases and pyrimidine salvage from Sporosarcina ureae, Sporolactobacillus inulinus, Lactobacillus fermentum, and Micrococcus luteus were compared to those of Bacillus subtilis. While the ATCases from Sporosarcina ureae, Sporolactobacillus inulinus, and L. fermentum were found to exhibit characteristics to that of Bacillus with respect to molecular weight and kinetics, M. luteus ATCase was larger at approximately 480 kDa. Furthermore, pyrimidine salvage in Sporosarcina ureae and M. luteus was identical to those of B. subtilis, while pyrimidine salvage of Sporolactobacillus inulinus and L. fermentum resembled that of the pseudomonads.
Contributing Partner: UNT Libraries
Evaluating Fish Impingement and Entrainment at the Comanche Peak Steam Electric Station

Evaluating Fish Impingement and Entrainment at the Comanche Peak Steam Electric Station

Date: May 1996
Creator: Bauml, George A. (George Arthur)
Description: This study was designed to determine if impingement and entrainment by cooling water intake at the Comanche Peak Steam Electric Station have an adverse impact upon the Squaw Creek Reservoir fish population. The yearly impingement of fish was estimated to be 262,994 of 14 species. The threadfin shad (Dorosoma petenense) accounted for 96% of this total. Entrainment of eggs and larvae for a five month period was estimated to be 15,989,987 and 42,448,794 respectively. Two fish population studies were performed on Squaw Creek Reservoir to help assess impact. It was determined that the losses due to impingement and entrainment have no adverse impact upon the fish population of Squaw Creek Reservoir.
Contributing Partner: UNT Libraries
A Study of a Selected Group of Science Related Characteristics of Non-Science Majors

A Study of a Selected Group of Science Related Characteristics of Non-Science Majors

Date: August 1957
Creator: Bearden, Bennie Paul
Description: The purpose of this study is to gather information related to the characteristics of two groups of undergraduate non-science majors; namely, those students who once considered science as a career and subsequently changed to a non-science major and those who have never considered a career in science. It is frequently observed that children in the elementary school have an intense interest in science. One of the principal concerns of this study is how and for what reasons has the interest in science changed between elementary school and college? It is also the purpose of this study to gather information related to the attitudes of these college students toward the science courses they have had in high school and toward their science teachers. In attempting to arrive at an answer, the group who once considered a science career and those who have never considered an occupational choice in a field of science will be compared in the following areas: 1. General information such as sex, age, size of high school attended, rank within their graduating classes, college classification and military experiences. 2. Occupations and hobbies of parents. 3. Experiences which may influence attitudes toward science such as elementary school science, high ...
Contributing Partner: UNT Libraries
Pyrimidine Salvage Enzymes in Microorganisms: Labyrinths of Enzymatic Diversity

Pyrimidine Salvage Enzymes in Microorganisms: Labyrinths of Enzymatic Diversity

Date: December 1995
Creator: Beck, Debrah A. (Debrah Ann)
Description: Pyrimidine salvage pathways are essential to all cells. They provide a balance of RNA synthesis with the biosynthetic pathway in pyrimidine prototrophs and supply all the pyrimidine requirements in auxotrophs. While the pyrimidine biosynthetic pathway is found in almost all organisms and is nearly identical throughout nature, the salvage pathway often differs from species to species, with aspects of salvage seen in every organism. Thus significant taxonomic value may be ascribed to the salvage pathway. The pyrimidine salvage pathways were studied in 55 microorganisms. Nine different salvage motifs, grouped I-IX, were identified in this study based on the presence of different combinations of the following enzymes: cytidine deaminase (Cdd), cytosine deaminase (Cod), uridine phosphorylase (Udp), uracil phosphoribosyltransferase (Upp), uridine hydrolase (Udh), nucleoside hydrolase (Nuh), uridine/cytidine kinase (Udk), 5'-nucleotidase and CMP kinase (Cmk).
Contributing Partner: UNT Libraries
Some Physiological Effects of Chlorine upon Two Chlorine Resistant Algae

Some Physiological Effects of Chlorine upon Two Chlorine Resistant Algae

Date: June 1966
Creator: Beddow, David G.
Description: This research is concerned specifically with the growth of two selected algae found surviving in chlorinated water in outdoor swimming pools. Unialgal cultures were used to determine the free chlorine residuals that these algae were able to tolerate.
Contributing Partner: UNT Libraries
A morphological study of the avian (Gallus domesticus) ductus arteriosi during hatching.

A morphological study of the avian (Gallus domesticus) ductus arteriosi during hatching.

Access: Use of this item is restricted to the UNT Community.
Date: May 2006
Creator: Belanger, Candace
Description: The ductus arteriosi (DA) are two blood vessels connecting the pulmonary arteries to the descending aorta in the avian embryo. Following hatching, the DA closes, separation of the systemic and pulmonary circulation. I present the morphological changes that occur in the chicken DA during prepipping, internal pipping, external pipping, and hatching. The avian DA consists of two distinct tissue types, a proximal and a distal portion. Histological examination shows developmental differences between the proximal and distal portions of the DA with regard to lumen occlusion, endothelial cells, smooth muscle and elastin. Endothelial cell proliferation begins to occur as early as external pipping, with the lumen almost completely occluded by the 3rd day of post-hatching life. Expression of vascular endothelial growth factor (VEGF) increases in avian endothelial cells during hatching. I provide a morphological timeline of changes in the DA as the chicken develops from embryo to hatchling.
Contributing Partner: UNT Libraries
Evidentiary Value of Condoms: Comparison of Durable Physical and Chemical Characteristics of Condoms

Evidentiary Value of Condoms: Comparison of Durable Physical and Chemical Characteristics of Condoms

Access: Use of this item is restricted to the UNT Community.
Date: May 2000
Creator: Belcher, Kelly Leigh
Description: Condom trace evidence must not be overlooked in sexual assault cases; understanding the chemical and physical characteristics of condoms is imperative if condoms are to be useful evidence. Previous research shows that condom identification is possible, but it is equally important to evaluate durability of condom residues versus time. Using FT-IR, this study examined vaginal swabs from subjects who self-sampled at intervals for up to 72 hours after having intercourse with a condom. This study investigated whether age and the stage of the menstrual cycle affected the durability of residues in the vagina over time. This study revealed that condoms containing nonoxynol-9, silicone-based lubricants, and particulates provide valuable information for identification, and that nonoxynol-9 specifically withstands the vaginal environment for up to 72 hours. Additionally, age and menstrual cycle both appeared to have an effect on the durability of residues although larger sample size is desirable.
Contributing Partner: UNT Libraries
The Adaptability and Present Status of Andropogon Ischaemum L. in Denton County, Texas

The Adaptability and Present Status of Andropogon Ischaemum L. in Denton County, Texas

Date: 1951
Creator: Belders, Floyd William
Description: This investigation has been made with reference to the adaptability of Andropogon ischaemum, King Ranch bluestem, to various soils, various slopes, and various erosion conditions in Denton County.
Contributing Partner: UNT Libraries