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A Novel Mechanism for Site-Directed Mutagenesis of Large Catabolic Plasmids Using Natural Transformation

Description: Natural transformation is the process by which cells take up DNA from the surrounding medium under physiological conditions, altering the genotype in a heritable fashion. This occurs without chemical or physical treatment of the cells. Certain Acinetobacter strains exhibit a strong tendency to incorporate homologous DNA into their chromosomes by natural transformation. Transformation in Acinetobacter exhibits several unique properties that indicate this system's superiority as a model for tra… more
Date: August 2001
Creator: Williamson, Phillip C.
Item Type: Refine your search to only Thesis or Dissertation
open access

Nucleotide Sequence Determination, Subcloning, Expression and Characterization of the xy1LT Region of the Pseudomonas putida TOL Plasmid pDK1

Description: The complete nucleotide sequence of the region encoding the DHCDH function of the pDK1 lower operon was determined. DNA analysis has shown the presence of two open reading frames, one gene consisting of 777 nucleotides encoding a polypeptide of 27.85 kDa and another gene of 303 nucleotides encoding a polypeptide of 11.13 kDa. The results of enzymatic expression studies suggest that DHCDH activity is associated only with xy1L. However although the addition of xy1T cell-free extracts to xy1L cell… more
Date: December 1992
Creator: Baker, Ronald F. (Ronald Fredrick)
Item Type: Refine your search to only Thesis or Dissertation
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Origin and Role of Factor Viia

Description: Factor VII, the initiator of the extrinsic coagulation cascade, circulates in human plasma mainly in its zymogen form, Factor VII and in small amounts in its activated form, Factor VIIa. However, the mechanism of initial generation of Factor VIIa is not known despite intensive research using currently available model systems. Earlier findings suggested serine proteases Factor VII activating protease, and hepsin play a role in activating Factor VII, however, it has remained controversial. In thi… more
Date: December 2013
Creator: Khandekar, Gauri
Item Type: Refine your search to only Thesis or Dissertation
open access

Phytoestrogens in Two Dioecious Species: Isolation, Characterization and Role in Plant Reproduction

Description: A highly specific steroid regulated transcription system system in Saccharomyces cerevisae was used to screen for phytoestrogens indioecious plants. Yeast cells were co-transformed with a human estrogen receptor expression plasmid and a reporter plasmid containing the E. coli β-galactosidase gene.
Date: May 1996
Creator: Maier, Camelia G. A. (Camelia Gabriela-Anca)
Item Type: Refine your search to only Thesis or Dissertation
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Postsynthetic Modifications of Glycolytic Enzymes of the Geriatric Immune System and in Fibroblasts from Premature Aging Diseases

Description: During mitogen-induced transformation of human lymphocytes, phosphoglycerate kinase (PGK) exhibits new electrophoretic forms (pl=8.5-8.9). Electrophoresis and electrofocusing showed that the new forms are not due to expression of the autosomally linked isozyme found in semen (PGK-B; pl=9.7). The multiple electrophoretic forms are the result of protease modification of sex-linked PGK-A isozyme.When peripheral lymphocytes from young persons are stimulated in vitro with phytohemagglutinin, a selec… more
Date: August 1982
Creator: Tollefsbol, Trygve O.
Item Type: Refine your search to only Thesis or Dissertation
open access

Posttranslational Modification of Proteins by ADP-ribosylation

Description: This work presents the development of a highly sensitive and selective chemical assay for mono(ADP-ribose) residues covalently bound to proteins in vivo. An extensive review of the literature is presented in the introduction of this work. The physiological.functions of mono(ADP-ribosyl)transferase activities associated with certain bacterial toxins (e.g., diphtheria, cholera and pertussis toxins) are well established. However, the roles of endogenous vertebrate transferases are unknown. The elu… more
Date: December 1984
Creator: Payne, David M. (David Michael)
Item Type: Refine your search to only Thesis or Dissertation
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Purification and Characterization of Proteolytic Aspartate Transcarbamoylase (ATCase) from Burkholderia cepacia 25416 and Construction of a pyrB1 Knock-out Mutant

Description: Burkholderia cepacia is a common soil bacterium of significance in agriculture and bioremediation. B. cepacia is also an opportunistic pathogen of humans causing highly communicable pulmonary infections in cystic fibrosis and immunocompromized patients. The pyrB gene encoding ATCase was cloned and ATCase was purified by the glutathione S-transferase gene fusion system. The ATCase in B. cepacia has been previously classified as a class A enzyme by Bethell and Jones. ATCase activity gels show… more
Date: December 2004
Creator: Kim, Seongcheol
Item Type: Refine your search to only Thesis or Dissertation
open access

Regulation, Evolution, and Properties of the ato Qperon and its Gene Products in Escherichia coli

Description: The regulation of short chain fatty acid metabolism has been examined. Metabolism of acetoacetate, and short chain fatty acids such as butyrate and valerate, is predicated upon the expression of genes of the ato operon. Acetoacetate induces expression of a CoA transferase (encoded by the atoDA genes) and expression of a thiolase (encoded by the atoB gene). Metabolism of saturated short chain fatty acids requires the activities of the transferase and thiolase and enzymes of 6-oxidation as well. … more
Date: August 1993
Creator: Chen, Chaw-Yuan
Item Type: Refine your search to only Thesis or Dissertation
open access

Regulation of Colony-Stimulating Factor-1 Biosynthesis

Description: Recent studies suggest that synthesis of the Colony-stimulating factor (CSF) is a well regulated process. However, the molecular mechanisms of the signal transduction of the various inducers of CSF such as monokines and lymphokines are not well understood. Using Interleukin 1 (IL-1) stimulation of CSF-1 in the MIA PaCa-2 cell line as a model system, the involvement of G-protein has been studied. The IL-1 induction of CSF-1 synthesis can be inhibited by both Pertussis toxin and Cholera toxin, wh… more
Date: May 1990
Creator: Ku, Chun-Ying
Item Type: Refine your search to only Thesis or Dissertation
open access

Regulation of pyrimidine biosynthesis and virulence factor production in wild type, Pyr- and Crc- mutants in Pseudomonas aeruginosa.

Description: Previous research in our laboratory established that pyrB, pyrC or pyrD knock-out mutants in Pseudomonas aeruginosa required pyrimidines for growth. Each mutant was also discovered to be defective in the production of virulence factors. Moreover, the addition of exogenous uracil did not restore the mutant to wild type virulence levels. In an earlier study using non-pathogenic P. putida, mutants blocked in one of the first three enzymes of the pyrimidine pathway produced no pyoverdine pigment w… more
Date: May 2006
Creator: Asfour, Hani
Item Type: Refine your search to only Thesis or Dissertation
open access

A regulatory role for N-acylethanolamine metabolism in Arabidopsis thaliana seeds and seedlings.

Description: N-Acylethanolamines (NAEs) are bioactive acylamides that are present in a wide range of organisms. Because NAE levels in seeds decline during imbibition similar to ABA, a physiological role was predicted for these metabolites in Arabidopsis thaliana seed germination and seedling development. There is also a corresponding increase of AtFAAH (fatty acid amide hydrolase), transcript levels and activity, which metabolizes NAE to ethanolamine and free fatty acids. Based on whole genome microarray s… more
Date: May 2009
Creator: Teaster, Neal D.
Item Type: Refine your search to only Thesis or Dissertation
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The regulatory roles of PyrR and Crc in pyrimidine metabolism in Pseudomonas aeruginosa

Description: The regulatory gene for pyrimidine biosynthesis has been identified and designated pyrR. The pyrR gene product was purified to homogeneity and found to have a monomeric molecular mass of 19 kDa. The pyrR gene is located directly upstream of the pyrBC' genes in the pyrRBC' operon. Insertional mutagenesis of pyrR led to a 50- 70% decrease in the expression of pyrBC', pyrD, pyrE and pyrF while pyrC was unchanged. This suggests that PyrR is a positive activator. The upstream regions of the pyrD, py… more
Date: August 2001
Creator: Patel, Monal V.
Item Type: Refine your search to only Thesis or Dissertation
open access

Stress Response by Alternative σ-factor, RpoH, and Analysis of Posttranslational Modification of the Heat Shock Protein, Dnak, in Escherichia coli

Description: Bacteria have developed specialized responses that involve the expression of particular genes present in a given regulon. Sigma factors provide regulatory mechanisms to respond to stress by acting as transcriptional initiation factors. This work focuses on σ32 during oxidative stress in Escherichia coli. The differential response of key heat shock (HS) genes was investigated during HS and oxidative stress using qPCR techniques. While groEL and dnaJ experienced increases in transcriptional respo… more
Date: May 2015
Creator: Martinez, Sarah N.
Item Type: Refine your search to only Thesis or Dissertation

Structural Analysis of the TOL pDK1 xylGFJQK Region and Partial Characterization of the xylF and xylG Gene Products

Description: TOL plasmids encode enzymes responsible for utilization of toluene and related aromatic compounds by Pseudomonas putida, ultimately converting them to central metabolic intermediates. The nucleotide sequence for the 5.6 kb xylGFJQK region of the pDK1 TOL meta operon was determined. DNA sequence analysis revealed the presence of five open reading frames corresponding to xylG (1458 bp), xylF (846 bp), xylJ (783 bp), xylQ (936 bp) and xylK (1047 bp), encoding predicted protein products of 51.6, 3… more
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Date: December 1999
Creator: Poulter, Melinda D.
Item Type: Refine your search to only Thesis or Dissertation

Structure-Function Studies on Aspartate Transcarbamoylase and Regulation of Pyrimidine Biosynthesis by a Positive Activator Protein, PyrR in Pseudomonas putida

Description: The regulation of pyrimidine biosynthesis was studied in Pseudomonas putida. The biosynthetic and salvage pathways provide pyrimidine nucleotides for RNA, DNA, cell membrane and cell wall biosynthesis. Pyrimidine metabolism is intensely studied because many of its enzymes are targets for chemotheraphy. Four aspects of pyrimidine regulation are described in this dissertation. Chapter I compares the salvage pathways of Escherichia coli and P. putida. Surprisingly, P. putida lacks several salvag… more
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Date: December 2003
Creator: Kumar, Alan P.
Item Type: Refine your search to only Thesis or Dissertation
open access

Studies on Plant-aphid Interactions: a Novel Role for Trehalose Metabolism in Arabidopsis Defense Against Green Peach Aphid

Description: Myzus persicae (Sülzer), commonly known as the green peach aphid (GPA), is a polyphagous insect that can infest over 100 families of economically important plants and is major pest for vegetable crops. This study utilizes the Arabidopsis-GPA model system with the aim to elucidate the role of the plant disaccharide trehalose in providing defense against GPA. This study demonstrates a novel role for TPS11 in providing defense against GPA. TPS11 expression was found to be transiently induced in Ar… more
Date: May 2012
Creator: Singh, Vijay
Item Type: Refine your search to only Thesis or Dissertation
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A Study of the Interaction of Co-Insult Treatments with Methylmercuric Chloride and X-Irradiation and Demonstration of a Peroxide Induced Protective Mechanism

Description: The initial purpose of this work was to investigate the interaction of methylmercuric chloride (MMC) and X-irradiation given as a co-insult upon the rat blood-brain barrier (BBB). The indicators used to determine BBB alterations were mortality and the in vivo tissue uptake of radioactive sulfate administered as 3 5S-sodium sulfate. The results of the interaction studies indicated a neutralization of effects when MMC and X-irradiation were given together. X-irradiation as a single insult general… more
Date: August 1975
Creator: Earhart, James M.
Item Type: Refine your search to only Thesis or Dissertation
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Subcloning and Nucleotide Sequence of Two Positive Acting Regulatory Genes, xy1R and xy1S, from the Pseudomonas putida HS1 TOL Plasmid PDK1

Description: TOL plasmids of Pseudomonas putida encode enzymes for the degradation of toluene and related aromatics. These genes are organized into two operons regulated by the Xy1R and Xy1S transcriptional activators. Previous analysis of the TOL pDK1 catechol-2,3-dioxygenase gene (xy1E) and a comparison of this gene to xy1E from the related TOL plasmid pWW0, revealed the existance of a substantial level of sequence homology (82%).
Date: May 1992
Creator: Chang, Teh-Tsai
Item Type: Refine your search to only Thesis or Dissertation
open access

Zebrafish Von Willebrand Factor

Description: In humans, von Willebrand factor (vWF) is a key component in hemostasis and acts as a 'cellular adhesive' by letting the circulating platelets bind to exposed subendothelium. It also acts as a carrier and stabilizer of factor VIII (FVIII). A dysfunction or reduction of vWF leads to von Willebrand disease (vWD), resulting in bleeding phenotype which affects 1% of the population. Currently there are a variety of animal models used for the study of vWF and vWD; however, they do not possess the … more
Date: August 2012
Creator: Carrillo, Maira M.
Item Type: Refine your search to only Thesis or Dissertation
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