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  Partner: UNT Libraries
 Department: Department of Biological Sciences
 Collection: UNT Theses and Dissertations
Evaluation of the Use of the Bivalves Ischadium recurvum Rafinesque, 1820 and Corbicula fluminea Muller, 1774 as Biological Indicators of Relative Water Quality in Terms of Growth and Upper Temperature Tolerance

Evaluation of the Use of the Bivalves Ischadium recurvum Rafinesque, 1820 and Corbicula fluminea Muller, 1774 as Biological Indicators of Relative Water Quality in Terms of Growth and Upper Temperature Tolerance

Date: December 1997
Creator: Hemming, Jon Michael
Description: Growth of mussels under laboratory conditions was examined under various food regimes in different water types and temperatures. Growth was less than would be useful as an indicator and comparisons with field exposures were of minimal value. The effects of organophosphates on bivalves were examined via toxicity tests, tissue concentration, and by controlling exposure through the use of physical constraints. Upper temperature tolerance of both bivalve species was examined with respect to different acclimation temperatures and organophosphate exposures. Deviations from control exposures occurred at some temperatures. Copper effectively lowered the mean heat coma temperatures of C. fluminea at some concentrations, however, chlorine exposures did not alter heat coma temperature.
Contributing Partner: UNT Libraries
The Removal of Linseed Oil Vapors by Biodegradation

The Removal of Linseed Oil Vapors by Biodegradation

Date: August 1996
Creator: Sukplang, Patamaporn
Description: Linseed oil is very important in industry but its use is limited due to noxious vapors produced by oxidation on exposure to air. Since some of the products are toxic, release of linseed oil vapors to the environment is normally prohibited. In order to remove the odorous compounds, a biofilter system based on bacterial metabolism was designed and the major premises of bioremediation were studied. A total of five bacterial strains capable of using linseed oil vapors as their sources of carbon and energy were isolated from soil. The individual organisms were also mixed to form a bacterial consortium. The mixed population was able to degrade linseed oil vapors with more than 99 per cent efficiency. According to this research, a successful biodegradation system was designed and, theoretically, this system could be applied to the removal of linseed oil vapors in any industrial plant air stream.
Contributing Partner: UNT Libraries
Cottonseed Microsomal N-Acylphosphatidylethanolamine Synthase: Identification, Purification and Biochemical Characterization of a Unique Acyltransferase

Cottonseed Microsomal N-Acylphosphatidylethanolamine Synthase: Identification, Purification and Biochemical Characterization of a Unique Acyltransferase

Date: December 1998
Creator: McAndrew, Rosemary S. (Rosemary Smith)
Description: N-Acylphosphatidylethanoiamine (NAPE) is synthesized in the microsomes of cotton seedlings by a mechanism that is possibly unique to plants, the ATP-, Ca2+-, and CoA-independent acylation ofphosphatidylethanolamine (PE) with unesterified free fatty acids (FFAs), catalyzed by NAPE synthase. A photoreactive free fatty acid analogue, 12-[(4- azidosalicyl)amino]dodecanoic acid (ASD), and its 125I-labeled derivative acted as substrates for the NAPE synthase enzyme.
Contributing Partner: UNT Libraries
The Role of Gabergic Inhibition in Modulating Receptive Field Size of Cuneate Neurons

The Role of Gabergic Inhibition in Modulating Receptive Field Size of Cuneate Neurons

Date: August 1997
Creator: Tennison, Cullen F.
Description: A blockade of GABAergic inhibition increases the receptive field(RF) size of most somatosensory cortex (SI) and some ventrobasal thalamus (VB) neurons. The results suggest RF size of cuneate neurons may be modulated through GABAa and GABAb receptors, independent of firing frequency.
Contributing Partner: UNT Libraries
Attenuation of Escherichia Coli Aspartate Transcarbamoylase Expressed in Pseudomonas Aeruginosa Mutant and Wild Type Strains

Attenuation of Escherichia Coli Aspartate Transcarbamoylase Expressed in Pseudomonas Aeruginosa Mutant and Wild Type Strains

Date: December 1994
Creator: Liu, Haiyan, 1966-
Description: No apparent repression of pyr gene expression in Pseudomonas aeruginosa is observed upon addition of exogenous pyrimidines to the growth medium. Upon introduction of the subcloned Escherichia coli pyrBI genes for aspartate transcarbamoylase (ATCase) into a P. aeruginosa pyrB mutant strain, repression was observed in response to exogenously fed pyrimidine compounds. The results proved that it is possible to bring about changes in pyrimidine nucleotide pool levels and changes in transcriptional regulation of gene expression as a result. Thus, the lack of regulatory control in P. aeruginosa pyr gene expression is not due to an inability to take up and incorporate pyrimidine compounds into metabolic pools, or to an inability of the RNA polymerase to respond to regulatory sequences in the DNA but is probably due to a lack of specific regulatory signals in the promoter of the genes themselves.
Contributing Partner: UNT Libraries
Quantitative Analysis of the Gabaergic System in Cat Primary Somatosensory Cortex and Its Relation to Receptive Field Properties

Quantitative Analysis of the Gabaergic System in Cat Primary Somatosensory Cortex and Its Relation to Receptive Field Properties

Date: May 1995
Creator: Li, Jianying
Description: Sensory neocortex contains a significant number of inhibitory neurons that use gamma-aminobutyric acid (GABA) as their neurotransmitter. Functional roles for these neurons have been identified in physiological studies. For example, in primary somatosensory cortex (SI), blockade of GABAa receptors with bicuculline leads to expansion of receptive fields (RFs). The magnitude of RF enlargement varies between SIpopulations of GABAergic neurons were identified by labeling specific calcium binding proteins.
Contributing Partner: UNT Libraries
Construction of a Physical Map of Moraxella (Branhamella) catarrhalis Strain ATCC25238

Construction of a Physical Map of Moraxella (Branhamella) catarrhalis Strain ATCC25238

Date: May 1999
Creator: Nguyen, Kim Thuy
Description: In order to gain a better understanding of this microorganismand its role in human pathogenesis, a physical map of Moraxella catarrhalis type strain ATCC25238 was constructed using pulsed field gel electrophoresis (PFGE) in combination with Southern hybridization techniques. Restriction endonucleases Not I, Rsr II, and Sma I were used to digest the chromosomal DNA. An overlapping circular map was generated by cross-hybridization of isolated radiolabeled fragments of Moraxella catarrhalis genomic DNA to dried PFGE gels. The number and location of the 16S and 23S ribosomal RNA genes were determined by digestion with l-Ceul enzyme and by Southern hybridization. Virulence-associated genes, the gene for β-lactamase, and housekeeping genes were also placed onto the physical map.
Contributing Partner: UNT Libraries
Temporal and Spatial Comparisons of Ambient Toxicity of the Trinity River in Relationship to an Effluent

Temporal and Spatial Comparisons of Ambient Toxicity of the Trinity River in Relationship to an Effluent

Date: December 1993
Creator: Hall, David B., 1958-
Description: A toxicological study was initiated because of concerns about allegations that the Texas Water Commission that effluent from the Dallas Central Wastewater Treatment Plant, which discharges into the Trinity River, was affecting downstream water quality. Monthly, flow-weighted composite effluent samples were collected. Grab samples were also collected upstream and downstream from the effluent from April 1989 to August 1991. Toxicity tests were conducted on these samples using Ceriodaphnia dubia as the test organism. Samples were collected four times during this study in which rainfall occurred prior to sampling. In every instance, this "first flush" of the watershed during a rising hydrograph was toxic to C. dubia upstream. Analyzing toxicity by season resulted in a statistically significantly lower neonate production in the effluent than in the river samples during the months of June, July, and August. This impact on neonate production was suspected of being caused by organic pesticides which are used for insect control on lawns. The effluent was never acutely toxic to C. dubia. Primarily, toxic occurrences in either the effluent or the river samples were primarily of a chronic nature. Overall, survival of C. dubia was affected more frequently at the upstream site than in the effluent or ...
Contributing Partner: UNT Libraries
Nesting Ecology of the Dickcissel (Spiza americana) on a Tallgrass Prairie Relict in North Central Texas

Nesting Ecology of the Dickcissel (Spiza americana) on a Tallgrass Prairie Relict in North Central Texas

Date: May 1993
Creator: Steigman, Kenneth Lee
Description: Eighty-three species of vascular plants were inventoried on the prairie relict during peak dickcissel nesting. Based on foliar cover and occurrence frequency, the five dominant plants were heath aster (Aster ericoides), eastern gammagrass (Tripsacum dactyloides), little bluestem (Schizachyrium scoparium), sensitive briar (Schrankia roemeriana) and meadow dropseed (Sporobolus asper). Sixty-one percent of dickcissel nests were constructed on or immediately next to three plant species: eastern gammagrass, sensitive briar and green milkweed.
Contributing Partner: UNT Libraries
Isolation and Characterization of the Operon Containing Aspartate Transcarbamoylase and Dihydroorotase from Pseudomonas aeruginosa

Isolation and Characterization of the Operon Containing Aspartate Transcarbamoylase and Dihydroorotase from Pseudomonas aeruginosa

Date: May 1993
Creator: Vickrey, John F. (John Fredrick), 1959-
Description: The Pseudomonas aeruginosa ATCase was cloned and sequenced to determine the correct size, subunit composition and architecture of this pivotal enzyme in pyrimidine biosynthesis. During the course of this work, it was determined that the ATCase of Pseudomonas was not 360,000 Da but rather present in a complex of 484,000 Da consisting of two different polypeptides (36,000 Da and 44,000 Da) with an architecture similar to that of E. coli ATCase, 2(C3):3(r2). However, there was no regulatory polypeptide found in the Pseudomonas ATCase.
Contributing Partner: UNT Libraries