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  Partner: UNT Libraries
 Degree Discipline: Biology
 Collection: UNT Theses and Dissertations
Aspartate transcarbamoylase of Aeromonas hydrophila

Aspartate transcarbamoylase of Aeromonas hydrophila

Date: December 2000
Creator: Higginbotham, Leah
Description: This study focused on the enzyme, aspartate transcarbamoylase (ATCase) from A. hydrophila, a Gram-negative bacterium found in fresh water. The molecular mass of the ATCase holoenzyme from A. hydrophila is 310 kDa. The enzyme is likely composed of 6 catalytic polypeptides of 34 kDa each and 6 regulatory polypeptides of 17 kDa each. The velocity-substrate curve for A. hydrophila ATCase is sigmoidal for both aspartate and carbamoylphosphate. The Km for aspartate was the highest to date for an enteric bacterium at 97.18 mM. The Km for carbamoylphosphate was 1.18 mM. When heated to 60 ºC, the specific activity of the enzyme dropped by more than 50 %. When heated to 100 ºC, the enzyme showed no activity. The enzyme's activity was inhibited by ATP, CTP or UTP.
Contributing Partner: UNT Libraries
Assimilation of Inorganic Nitrogen by Aquatic Actinomycetes

Assimilation of Inorganic Nitrogen by Aquatic Actinomycetes

Date: August 1962
Creator: Davis, Ernst M.
Description: It was the purpose of this investigation to present laboratory data concerning the assimilation of inorganic nitrogen by the aquatic actinomycetes. The strains of aquatic actinomycetes under consideration represented a cross section of those currently under culture at North Texas State University.
Contributing Partner: UNT Libraries
Assimilation of Organic Carbon by Aquatic Actinomycetes

Assimilation of Organic Carbon by Aquatic Actinomycetes

Date: August 1963
Creator: Shao, Yi-min
Description: There were two purposes of this investigation: the first was to develop a method for studying spore germination, hyphal growth and mycelial development of the aquatic actinomycetes under the microscope so that the life cycle of this organism could be continuously followed. The second purpose was to determine the rate of carbon utilization from various types of nutritional sources, and to correlate this with the colony development and spore formation.
Contributing Partner: UNT Libraries
The Autecology of Celtis Laevigata in Flood Plain Forests of Denton County, Texas

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

Date: January 1970
Creator: Hander, Lecil B.
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.
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Autoimmunity of Periodontitis

Autoimmunity of Periodontitis

Date: August 1963
Creator: Miller, Katy Jo Coyle
Description: The purpose of this investigation is to determine if auto-antibodies are demonstrable in inflammatory periodontal disease using methods other than those of Novotny.
Contributing Partner: UNT Libraries
Automated Low-cost Instrument for Measuring Total Column Ozone

Automated Low-cost Instrument for Measuring Total Column Ozone

Access: Use of this item is restricted to the UNT Community.
Date: May 2006
Creator: Nebgen, Gilbert Bernard
Description: 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 ...
Contributing Partner: UNT Libraries
Autoradiographic localization of carbachol-induced second messenger response in the rat spinal cord following inflammation.

Autoradiographic localization of carbachol-induced second messenger response in the rat spinal cord following inflammation.

Date: May 2002
Creator: Moore, Jack
Description: This study examined central mechanisms of persistent pain using an autoradiographic technique to localize phosphoinositide hydrolysis (PI) in the rat spinal cord dorsal horn. The lateral half of laminae I-II showed the highest levels of baseline PI turnover and carbachol-stimulated PI turnover in normal animals as well as after inflammation. Inflammation resulted in increased baseline PI turnover in this region of the ipsilateral (76%) and contralateral (65%) dorsal horns. Carbachol increased PI turnover in this region in normal rats (55%) and following inflammation (ipsilateral: 46%, contralateral: 45%). The absolute magnitudes of these increases were 1.85, 2.71, and 2.51 nCi/mg, respectively. The results of this study demonstrate the involvement of PI turnover in neural mechanisms of persistent pain, and provide evidence for the involvement of cholinergic systems in this process. Because spinal cholinergic systems have been reported to be anti-nociceptive, the present results appear to reflect an upregulation of anti-nociceptive activity in response to inflammation. Thus, the spinal cholinergic system may be a regulatory site within the anti-nociceptive pathway, and may provide an attractive target for the development of new therapeutic agents.
Contributing Partner: UNT Libraries
Bacterial Antibiotic Properties of the Oleoresins of Thirty Summer Flowering Spermatophytes

Bacterial Antibiotic Properties of the Oleoresins of Thirty Summer Flowering Spermatophytes

Date: 1950
Creator: Marnock, Edna Leotah
Description: The purpose of this investigation is to add to the present day knowledge concerning the presence of antibiotics in additional members of the spermatophyte group of plants.
Contributing Partner: UNT Libraries
Bacterial challenge in Lumbricus terrestris: A terrestrial invertebrate immunotoxicity model.

Bacterial challenge in Lumbricus terrestris: A terrestrial invertebrate immunotoxicity model.

Date: May 2007
Creator: McDonald, Jennifer C.
Description: A bacterial challenge assay was developed utilizing the earthworm, Lumbricus terrestris, in order to assess potential immunotoxic effects from exposure to specific polychlorinated biphenyl congeners. Earthworms were inoculated with Aeromonous hydrophila, establishing a 10-day LD50. In vitro assays for effects of PCBs on phagocytosis agreed with mammalian studies, demonstrating potent suppression of phagocytosis by the non-coplanar PCB congener 138 and no suppression by the coplanar congener 126. However, when the effects of the two PCB congeners were evaluated for suppression of resistance to a whole animal infection challenge assay, coplanar PCB 126 decreased the ability of L. terrestris to withstand infection while non-coplanar PCB 138 did not.
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A Bacterial Spectrum of Antibiotic "S"

A Bacterial Spectrum of Antibiotic "S"

Date: 1949
Creator: Matthews, J. Les (James Les), 1926-
Description: This thesis is an investigation of Antibiotic "S" with the purpose of determining which organisms it has a marked effect on, the amount required to cause inhibition, its action in blood, and its therapeutic effect and toxicity in laboratory animals.
Contributing Partner: UNT Libraries