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Carbachol- and ACPD-Induced Phosphoinositide Responses in the Developing Rat Neocortex (open access)

Carbachol- and ACPD-Induced Phosphoinositide Responses in the Developing Rat Neocortex

Signal transduction via the phosphoinositide (PI) second messenger system has key roles in the development and plasticity of the neocortex. The present study localized PI responses to individual cortical layers in slices of developing rat somatosensory cortex. The acetylcholine agonist carbachol and the glutamate agonist trans-1-amino-1,3-cyclopentanedicarboxylic acid (ACPD) were used to stimulate PI turnover. The PI responses were compared to the distribution of the corresponding PI-linked receptors in order to investigate the regional ontogeny of PI coupling to receptors in relation to neural development. The method for assessing PI turnover was modified from Hwang et al. (1990). This method images the PI response autoradiographically through the localizaton of [3H]cytidine that has been incorporated into the membrane-bound intermediate, cytidine diphosphate diacylglycerol. In each age group (postnatal days 4-30), carbachol resulted in more overall labeling than ACPD. For both agonists, the response peaked on postnatal day 10 (P10) and was lowest in the oldest age group. The laminar distribution of the carbachol PI response from P4-P16 corresponded fairly well with the laminar distribution of [3H]quinuclidinyl benzilate binding (Fuchs, 1995). However, in the subplate layer the carbachol response was strong while receptor binding was minimal. The carbachol response decreased after postnatal day 10, …
Date: August 2000
Creator: Hartgraves, Morri D.
System: The UNT Digital Library
Characterization of the Aspartate Transcarbamoylase that is Found in the pyrBCÂ’ Complex of Bordetella Pertussis (open access)

Characterization of the Aspartate Transcarbamoylase that is Found in the pyrBCÂ’ Complex of Bordetella Pertussis

An aspartate transcarbamoylase (ATCase) gene from Bordetella pertussis was amplified by PCR and ligated into pT-ADV for expression in Escherichia coli. This particular ATCase (pyrB) was an inactive gene found adjacent to an inactive dihydroorotase (DHOase) gene (pyrC'). This experiment was undertaken to determine whether this pyrB gene was capable of expression alone or if it was capable of expression only when cotransformed with a functional pyrC'. When transformed into E. coli TB2 pyrB-, the gene did not produce any ATCase activity. The gene was then co-transformed into E. coli TB2 pyrB- along with a plasmid containing the pyrC' gene from Pseudomonas aeruginosa and assayed for ATCase activity. Negative results were again recorded.
Date: December 2001
Creator: Dill, Michael T
System: The UNT Digital Library
Degradation of Humic Substances by Aquatic Bacteria (open access)

Degradation of Humic Substances by Aquatic Bacteria

A variety of aquatic bacteria were isolated and tested for their ability to degrade humic substances and their aromatic residues/monomers which serve as precursors of the trihalomethanes (THMs) found in chlorinated drinking waters. The majority of them were Gram-negative, oxidative types dominated by pseudomonads. Most of the 146 isolates were found to utilize as their sole source of carbon several or more of ten aromatic compounds known to be products of degradation of humus and also to be precursors of THMs. The aromatics tested, with percent of the isolates utilizing the compound in parentheses, were: p-hydroxybenzoate (49), vanillic acid (48), 3,5-dihydroxybenzoic acid (16), syringic acid (19), vanillin (30), benzoic acid (27), ferulic acid (34), resorcinol (9), catechol (8) and protocatechuic acid (27).
Date: August 1985
Creator: Baiu, Saleh Hamed Salem
System: The UNT Digital Library
L-asparaginase II Production by Escherichia coli (open access)

L-asparaginase II Production by Escherichia coli

Growth of Escherichia coli A-l under aerobic conditions in an enriched medium with a total amount of 0.2 per cent glucose was biphasic and asparaginase II activity was detected after depletion of ammonia from the growth medium in the second phase of growth. Glucose was exhausted two hours before ammonia and three hours before asparaginase II activity was detected. The concentration of 3',5'-cyclic adenosine monophosphate was found to fluctuate when the dissolved oxygen in the medium reached a low level, when glucose and ammonia were exhausted, and when the cells entered the second stationary phase of growth. Culture tube studies of the growth of E_j_ coli A-l in three per cent nutrient broth with varied concentrations of ammonium chloride and potassium nitrate gave lower specific activity of asparaginase II when this was compared to that seen in three per cent nutrient broth alone. The addition of glucose to the same medium before asparaginase II activity was detected resulted in the production of acid by E. coli A-l with cessation of growth; however, addition after L-asparaginase synthesis had started did not affect the specific activity of the enzyme. The addition of ammonium chloride suppressed L-asparaginase synthesis, but addition after enzyme synthesis …
Date: May 1985
Creator: Johnson, Terrance L. (Terrance Lewyne), 1950-
System: The UNT Digital Library
Biodegradation of Certain Petroleum Product Contaminants in Soil and Water By Selected Bacteria (open access)

Biodegradation of Certain Petroleum Product Contaminants in Soil and Water By Selected Bacteria

Soil contamination by gasoline underground storage tanks is a critical environmental problem. The results herein show that in situ bioremediation using indigenous soil microorganisms is the method of choice. Five sites were selected for bioremediation based on the levels of benzene, toluene, ethylbenzene and xylene and the amount of total petroleum hydrocarbons in the soil. Bacteria capable of degrading these contaminants were selected from the contaminated sites and grown in 1,200 I mass cultures. These were added to the soil together with nutrients, water and air via PVC pipes.
Date: December 1995
Creator: Nevárez-Moorillón, Guadalupe Virginia
System: The UNT Digital Library
Scientific Considerations of Olestra as a Fat Substitute (open access)

Scientific Considerations of Olestra as a Fat Substitute

Olestra is, a sucrose polyester, a noncaloric fat substitute, made from sucrose and several fatty acid esters. It has been approved by the FDA as a food additive used in preparing low-fat deep-frying foods such as savory snacks. Available literature on olestra was evaluated that had both positive and negative connotations. Clinical trials in numerous species of animals including humans were conducted to determine if olestra would affect the utilization and absorption of macro- and micronutrients; the effects of olestra on growth, reproduction, or its toxicity were also examined. The roles of olestra as a fat substitute, how it could effect on humans and the environment, and the potential impacts from its use in large amounts were assessed. Olestra can be removed from the environment by aerobic bacteria and fungi which may be isolated from activated sludge and soils.
Date: December 1999
Creator: Rattagool, Kullakan
System: The UNT Digital Library
Requirements for Cell-Free Cyanide Oxidation by Pseudomonas Fluorescens NCIMB 11764 (open access)

Requirements for Cell-Free Cyanide Oxidation by Pseudomonas Fluorescens NCIMB 11764

The involvement of cyanide oxygenase in the metabolism of pyruvate and a-ketoglutarate-cyanohydrin was investigated and shown to occur indirectly by the consumption of free cyanide arising from the cyanohydrins via chemical dissociation. Thus, free cyanide remains the substrate, for which the enzyme displays a remarkably high affinity (Kmapp,4 mM). A model for cyanide utilization is therefore envisioned in which the substrate is initially detoxified by complexation to an appropriate ligand followed by enzymatic oxidation of cyanide arising at sublethal levels via chemical dissociation. Putative cyanide oxygenase in cell extracts consumed both oxygen and NADH in equimolar proportions during cyanide conversion to CO2 and NH3 and existed separately from an unknown heat-stable species responsible for the nonenzymatic cyanide-catalyzed consumption of oxygen. Evidence of cyanide inhibition and nonlinear kinetics between enzyme activity and protein concentration point to a complex mechanism of enzymatic substrate conversion.
Date: August 2000
Creator: Parab, Preeti
System: The UNT Digital Library

BioInformatics, Phylogenetics, and Aspartate Transcarbamoylase

Access: Use of this item is restricted to the UNT Community
In this research, the necessity of understanding and using bioinformatics is demonstrated using the enzyme aspartate transcarbamoylase (ATCase) as the model enzyme. The first portion of this research focuses on the use of bioinformatics. A partial sequence of the pyrB gene found in Enterococcus faecalis was submitted to GenBank and was analyzed against the contiguous sequence from its own genome project. A BLAST (Basic Local Alignment Search Tool; Atschul, et al., 1990) was performed in order to hypothesize the remaining portion of the gene from the contiguous sequence. This allowed a global comparison to other known aspartate transcarbamoylases (ATCases) and once deduced, a translation of the sequence gave the stop codon and thus the complete sequence of the open reading frame. When this was complete, upstream and downstream primers were designed in order to amplify the gene from genomic DNA. The amplified product was then sequenced and used later in phylogenetic analyses concerning the evolution of ATCase. The second portion of this research involves taking multiple ATCase nucleotide sequences and performing phenetic and phylogenetic analyses of the archaea and eubacter families. From these analyses, ancestral relationships which dictate both structure and function were extrapolated from the data and discussed.
Date: August 2000
Creator: Cooke, Patrick Alan
System: The UNT Digital Library

Adherence and Haemagglutination of Moraxella Catarrhalis.

Access: Use of this item is restricted to the UNT Community
M. catarrhalis is a gram-negative diplococci frequently associated with infections of the upper respiratory tract. During the past decade, some preliminary studies have attempted to elucidate mechanisms of adherence and haemagglutination of M. catarrhalis. These studies have reported, in many cases, inconsistent results. There are two purposes of this research. First, identify mechanisms that may potentially be associated with the adherence and haemagglutination of M. catarrhalis. Second, suggest research directions that may be fruitful in clarifying these mechanisms.
Date: August 2000
Creator: Kosterman, Edward, III
System: The UNT Digital Library
Comparative Biochemistry and Evolution of Aspartate Transcarbamoylase from Diverse Bacteria (open access)

Comparative Biochemistry and Evolution of Aspartate Transcarbamoylase from Diverse Bacteria

Aspartate transcarbamoylase (ATCase) catalyzes the first committed step in pyrimidine biosynthesis. Bacterial ATCases are divided into three classes, A, B and C. Class A ATCases are largest at 450-500, are. dodecamers and represented by Pseudomonas ATCase. The overlapping pyrBC' genes encode the Pseudomonases ATCase, which is active only as a 480 kDa dodecamer and requires an inactive pyrC'-encoded DHOase for ATCase activity. ATCase has been studied in two non-pathogenic members of Mycobacterium, M. smegmatis and M. phlei. Their ATCases are dodecamers of molecular weight 480 kDa, composed of six PyrB and six PyrC polypeptides. Unlike the Pseudomonas ATCase, the PyrC polypeptide in these mycobacteria encodes an active DHOase. Moreover, the ATCase: DHOase complex in M. smegmatis is active both as the native 480 kDa and as a 390 kDa complex. The latter lacks two PyrC polypeptides yet retains ATCase activity. The ATCase from M. phlei is similar, except that it is active as the native 480 kDa form but also as 450,410 and 380 kDa forms. These complexes lack one, two, and three PyrC polypeptides, respectively. By contrast,.ATCases from pathogenic mycobacteria are active only at 480 kDa. Mycobacterial ATCases contain active DHOases and accordingly. are placed in class A1 . …
Date: May 1999
Creator: Hooshdaran, Massoumeh Ziba
System: The UNT Digital Library
A Study of the Water-Soluble Antigens from Virulent and Attenuated Biotypes of Brucella abortus (open access)

A Study of the Water-Soluble Antigens from Virulent and Attenuated Biotypes of Brucella abortus

Through chemical analysis and ion exchange chromatography of watersoluble antigens, this investigation supports the view that the majority of differences between the biotypes are quantitative. It was also found that strains demonstrate distinct, qualitative differences when compared to the attenuated strain 19 by immunodiffusion and thin-layer polyacrylamide gel, isoelectric focusing. These differences include the presence of antigens on virulent strains that are absent on strain 19. In addition, one antigen absent on strain 19, was found common to each virulent biotype. Finally, the results from immunodiffusion experiments, employing adsorbed and non-adsorbed immune globulins, indicate that at least some water-soluble antigens are exposed on the cell surface and that their distribution among the biotypes varies.
Date: May 1977
Creator: Brodeur, Richard D.
System: The UNT Digital Library
Aquatic Heterotrophic Bacteria Active in the Biotransformation of Anthracene and Pentachlorophenol (open access)

Aquatic Heterotrophic Bacteria Active in the Biotransformation of Anthracene and Pentachlorophenol

Dominant genera of bacteria were isolated from three river waters during anthracene and pentachlorophenol biotransformation studies. The genera Pseudomonas, Acinetobacter, Micrococcus, Chromobacterium, Alcaligenes, Azomonos, Bacillus, and Flavobacterium were capable of biotransforming one or both of these compounds. These isolates were subjected to further biotransformation tests, including river water and a basal salt medium with and without additional glucose. The results of these experiments were evaluated statistically. It was concluded that only a limited number of the bacteria identified were able to transform these chemicals in river water. The addition of glucose to the growth medium significantly affected the biotransformation of these chemicals. It was also determined that the size of the initial bacterial population is not a factor in determining whether biotransformation of anthracene or pentachlorophenol can occur.
Date: August 1985
Creator: Entezami, Azam A. (Azam Alsadat)
System: The UNT Digital Library
Intracellular Location of Carotenoid Pigments in Yeast-Phase Cells of Wangiella Dermatitidis and Cell Wall Morphology After Enzyme Treatment (open access)

Intracellular Location of Carotenoid Pigments in Yeast-Phase Cells of Wangiella Dermatitidis and Cell Wall Morphology After Enzyme Treatment

Carotenoid pigments in W. dermatitidis, the first pathogenic, dematiaceous fungus in which carotenoid pigments nave been reported, are located primarily (81%) in lipid organelles which floated on the surface of the supernatant fraction of lysed cells. Pigment in this fraction could be extracted with ethyl ether without prior treatment with acetone indicating the pigment is unbound in the lipid organelle. Eight percent remains after exhaustive ether extraction and is recovered after the sample is treated with acetone indicating this fraction is non-covalently bound to proteins in the membranes associated with the lipid organelle. The remaining pigment (about 12%) represents contamination of the supernatant with the lipid organelles.
Date: December 1991
Creator: Foster, Linda Ann
System: The UNT Digital Library
Induction of Interferon Messenger RNA and Expression of Cellular Oncogenes in Human Lymphoblastoid Cells (open access)

Induction of Interferon Messenger RNA and Expression of Cellular Oncogenes in Human Lymphoblastoid Cells

The purposes of this study was to demonstrate the induction of alpha interferon mRNA in Sendai virus-induced Namalava cells, to follow the level of alpha interferon mRNA synthesis at the transcriptional level, and to determine whether the Namalava cell line expresses the c-myc oncogene and to what degree. The amount of c-myc message deteted in Namalva cell RNA was about one-tenth that of Daudi cell RNA, whereas no difference in the amount of the c-Ha-ras message was observed between the two cell lines.
Date: December 1986
Creator: Mahmoudi, Massoud
System: The UNT Digital Library
The Detection of Poliovirus in Denton Sewage by Immunofluorescence and Immunodiffusion Techniques (open access)

The Detection of Poliovirus in Denton Sewage by Immunofluorescence and Immunodiffusion Techniques

Several final sewage effluents from the Denton Disposal Plant were demonstrated to contain Poliovirus types II and III. Pleated encapsulated filters at pH3.5 enhanced the recovery of the Poliovirus at a higher tier in comparison with nitrocellulose filter (Millipore) and glass fiber filter of pore size 0.45u. This thesis explores problems that face us today in our quest to eliminate viral pathogens from the natural and waste water needed for human, domestic, and industrial consumption. Preliminary experiments concern the use of immunofluorescence, and immunodiffusion techniques as a means of poliovirus identification, which invariably suggests that these techniques may be useful as rapid screening procedures of water samples for presence of potentially pathogenic viruses.
Date: August 1975
Creator: Olaiya, Felix Ayodele
System: The UNT Digital Library
Studies of the Membrane and DNA Gyrase Inhibiting Antibiotics on Pigment Synthesis in Corynebacterium Poinsettiae (open access)

Studies of the Membrane and DNA Gyrase Inhibiting Antibiotics on Pigment Synthesis in Corynebacterium Poinsettiae

The purpose of this study was (1) to determine whether a correlation exists among the protein profiles, extracted from cell membranes of mutants belonging to five pigment cluster groups, (2) to locate the protein moiety and cartenoprotein complex in the membranes of wild type and colorless mutant (designated W-19) of C. poinsettae and to show whether there are any structural differences between cell membranes of the wild type and a colorless mutant, (3) to determine the effect of six antibiotics on cartenoid gene expression.
Date: August 1988
Creator: Tabarya, Daniel
System: The UNT Digital Library
Immune Response of the Rat to Outer Membrane Proteins of Legionella Pneumophila (open access)

Immune Response of the Rat to Outer Membrane Proteins of Legionella Pneumophila

Outer membrane proteins (OMPs) were recovered from eleven strains (eight serogroups) of Legionella pneumophila by sequential treatment with Tris buffer (pH 8), citrate buffer(pH 2.75) and Tris buffer (pH 8). Transmission electron microscopy revealed clearly the separation of the outer membrane from the bacteria. The development of delayed hypersensitivity was also noted by measuring the area of arythema and induration produced by intradermal injections of the MPSs from Chicago 8 strain. The adjuvants enhanced greatly both active and cell-meditated immunity (CMI). Transient lymphocytopenia with a slight rise in neutrophils was noted in each of the immunized groups. Intraperitoneal challenge, seven days after the OMP booster, of one LD (1.5 x10^6) of legionellae resulted in lymphocytopenia with elevated neutrophils. All immunized rats survived the challenge, although those in the saline-OMP group were clearly the sickest. Post-challenge, legionella antibody titers rose greatly and CMI was heightened. Passive immunization (homologous and heterologous) was found to protect the rats from a challenge of on LD. Actively-immunized rats retained their immunity for at least six months as determined by their resistance to a second challenge.
Date: August 1985
Creator: Ahanotu, Ejemihu Ndu
System: The UNT Digital Library
Discovery of a Thermophilic Nitrogen Fixing Bacterium (open access)

Discovery of a Thermophilic Nitrogen Fixing Bacterium

The thermophilic bacterium designated NT-7 was shown to reduce acetylene to ethylene at 35 C. It was found that the organism does not reduce acetylene when it is grown in Burk's medium with 0.3 per cent (w/v) NH4 N0 3 . Reduction of acetylene at 55 C could not be demonstrated due to insolubility of acetylene in Burk's medium at this temperature. It was shown that the bacterium NT-7 can not grow in the absence of atmospheric nitrogen at 55 C when combined nitrogen is not supplied with the nutrient medium. All these characteristics were used to prove that NT-7 is a nitrogen fixing bacterium. Identification procedures confirmed a previous finding that the organisms are rod shaped cells possessing endoepores. Further tests showed that NT-7 is obligately aerobic and motile.
Date: August 1977
Creator: Tabarya, Daniel
System: The UNT Digital Library
Characterization of the Pigment-Protein and Pigment-ester of Xanthomonas Campestris Pv. Juglandis (open access)

Characterization of the Pigment-Protein and Pigment-ester of Xanthomonas Campestris Pv. Juglandis

The objectives of this project were to develop a high performance liquid chromatographic method for separating the pigment esters mixture, to determine the locations of the pigment moiety in the isolated esters using pholosiphases, and to characterize the pigment-protein complex and determine its distribution in other bacteria. Saponification of the two pigment esters 1 and 2 with aqueous KOH yielded two free pigments on TLC plates developed by two solvent systems. The fasters moving of these two free pigments co-chromatographed with the one free pigment produced from each pigment ester by phospholipase A2 treatment. This suggests that the pigment molecule is a methoxy derivative of xanthomonadin and is esterified to the 2-position of the glycerol moiety of each pigment ester. No free pigment was released from phospholipases C and D treatment of the two pigment esters, indicating that pigment is not esterified to the sorbitol or phosphate moiety of pigment esters 1 or 2.
Date: May 1987
Creator: Lawani, Leonard Olu
System: The UNT Digital Library
Characterization of the Pigment-Protein Complex in Corynebacterium Poinsettiae (open access)

Characterization of the Pigment-Protein Complex in Corynebacterium Poinsettiae

The purpose of this study was to completely characterize the protein moiety in the caroteno complex in C. poinsettae, determine if the distribution and level of protein in the pigment-protein complex in membranes of the wild type and in a colorless mutant could account for the differences in the stability of the membrane, and to determine if this protein is common to other pigmented and non-pigmented organisms. Also, electron microscopy of cell membranes of C. poinsettiae which had been exposed to gold-labelled antibody against the protein moitey of the pigment-protein complex, demonstrating that the protein is randomly distributed in the membranes of both wild type and colorless mutant.
Date: May 1986
Creator: Ebadati, Nasrollah D.
System: The UNT Digital Library