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open access

Mutation Rate Analysis of the Human Mitochondrial D-loop and its Implications for Forensic Identity Testing

Description: To further facilitate mitochondrial DNA (mtDNA) sequence analysis for human identity testing, a better understanding of its mutation rate is needed. Prior to the middle 1990's the mutation rate applied to a forensic or evolutionary analysis was determined by phylogenetic means, This method involved calculating genetic distances as determined by amino acid or DNA sequence variability within or between species. The mutation rate as determined by this method ranged from 0.025-0.26 nucleotide subst… more
Date: May 2000
Creator: Warren, Joseph E.
open access

Isolation and analysis of cotton genomic clones encompassing a fatty acid desaturase (FAD2) gene

Description: Polyunsaturated fatty acids are major structural components of plant chloroplast and endoplasmic reticulum membranes. Two fatty acid desaturases (designated FAD2 and FAD3) desaturate 75% of the fatty acids in the endoplasmic reticulum. The w -6 fatty acid desaturase (FAD2) may be responsible for cold acclimation response, since polyunsaturated phospholipids are important in helping maintain plant viability at lowered temperatures. To study regulation of FAD2 gene expression in cotton, a FAD2 g… more
Date: May 2001
Creator: Kongcharoensuntorn, Wisatre
open access

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.
open access

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.
open access

A Possible Role of Ascorbate in Boron Deficient Radish (Raphanus sativa L. cv. Cherry Belle)

Description: The most apparent symptom of boron deficiency in higher plants is a cessation of growth. Deficiency causes a reduction in ascorbate concentration and the absorption of nutrient ions. Addition of ascorbate temporarily relieves deficiency symptoms. In boron sufficient plants the addition of ascorbate to media causes an increased uptake of nutrients. In an attempt to discover if ascorbate addition to deficient plants causes increased ion uptake, radish plants were grown hydroponically in four dif… more
Date: August 2001
Creator: Sedlacek, Theresa D.
open access

Purification of Aspartate Transcarbamoylase from Moraxella (Branhamella) catarrhalis

Description: The enzyme, aspartate transcarbamoylase (ATCase) from Moraxella (Branhamella) catarrhalis, has been purified. The holoenzyme has a molecular mass of approximately 510kDa, harbors predominantly positive charges and is hydrophobic in nature. The holoenzyme possesses two subunits, a smaller one of 40 kDa and a larger one of 45 kDa. A third polypeptide has been found to contribute to the overall enzymatic activity, having an approximate mass of 55 kDa. The ATCase purification included the generati… more
Date: August 2001
Creator: Stawska, Agnieszka A.

Characterization of Moraxella bovis Aspartate Transcarbamoylase

Description: Aspartate transcarbamoylase (ATCase) catalyzes the first committed step in the pyrimidine biosynthetic pathway. Bacterial ATCases have been divided into three classes, class A, B, and C, based on their molecular weight, holoenzyme architecture, and enzyme kinetics. Moraxella bovis is a fastidious organism, the etiologic agent of infectious bovine keratoconjunctivitis (IBK). The M. bovis ATCase was purified and characterized for the first time. It is a class A enzyme with a molecular mass of 4… more
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Date: December 2001
Creator: Hooshdaran, Sahar
open access

Molecular cloning and analysis of the genes for cotton palmitoyl-acyl carrier protein thioesterase (PATE) and Δ-12 fatty acid desaturase (FAD2-3) and construction of sense and anti-sense PATE plasmid vectors for altering oilseed composition of transgenic cotton plants.

Description: A cotton PATE cDNA clone has a 1.7-kb insert with an coding region for 410 amino acids, lacking codons for the three N-terminal amino acids. The predicted amino acid sequence of the PATE preprotein has a characteristic stromal-targeting domain and a 63% identity to the Arabidopsis FatB1 thioesterase sequence. A cotton genomic clone containing a 17.4-kb DNA segment was found to encompass a palmitoyl-ACP thioesterase (FatB1) gene. The gene spans 3.6 kb with six exons and five introns. The six… more
Date: May 2002
Creator: Nampaisansuk, Mongkol
open access

Dna Profiling of Captive Roseate Spoonbill (Ajaia Ajaja) Populations As a Mechanism of Determining Lineage in Colonial Nesting Birds.

Description: Roseate spoonbills are colonial nesting birds with breeding grounds extending from the United States Gulf coast to the pampas of Argentina. The U.S. population suffered a severe bottleneck from 1890 to 1920. The population's recovery was slow and partially credited to migrations from Mexican rookeries, but a gene pool reduction would be expected. Five polymorphic Spoonbill autosomal short tandem repeat (STR) loci [three (GAT)n, one (AAAG)n and one (GT)n] and one Z/W-linked microsatellite exhibi… more
Date: May 2002
Creator: Sawyer, Gregory M.

Characterization of cDNA and Genomic Clones for a Palmitoyl-acyl Carrier Protein Thioesterase and an Osmotin-Like PR5 Protein in Gossypium Hirsutum.

Description: Putative cotton cDNA clones and cognate genomic clones for a palmitoyl-acyl carrier protein (ACP) thioesterase (PATE) and an osmotin-like pathogenesis-related 5 (PR5) protein have been isolated and characterized. PATE is a class B fatty acid thioesterase with specificity for saturated long-chain fatty acids such as palmitate, and is implicated as a key enzyme to be targeted for regulation of fatty acid synthesis in order to alter cotton seed oil profiles. A nearly full-length 1.7-kb cDNA clon… more
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Date: May 2002
Creator: Yoder, David W.
open access

Map-based cloning of the NIP gene in model legume Medicago truncatula.

Description: Large amounts of industrial fertilizers are used to maximize crop yields. Unfortunately, they are not completely consumed by plants; consequently, this leads to soil pollution and negative effects on aquatic systems. An alternative to industrial fertilizers can be found in legume plants that provide a nitrogen source that is not harmful for the environment. Legume plants, through their symbiosis with soil bacteria called rhizobia, are able to reduce atmospheric nitrogen into ammonia, a biologic… more
Date: May 2007
Creator: Morris, Viktoriya
open access

Analysis of the Expression Profiles of Two Isoforms of the Antifungal Protein Osmotin from Gossypium hirsutum

Description: The expression of two cotton osmotin genes was evaluated in terms of the mRNA and protein expression patterns in response to chemical inducers such as ethylene, hydrogen peroxide, and sodium chloride. Reverse transcriptase-polymerase chain reactions (RT-PCR) indicated that osmotin mRNAs are expressed constitutively in root tissues of cotton plants, and that they are rapidly induced in leaf and stem tissues upon ethylene treatment. Real time RT-PCR indicated that osmotin transcript levels were… more
Date: May 2007
Creator: Spradling, Kimberly Diane
open access

Evaluation of Zinc Toxicity Using Neuronal Networks on Microelectrode Arrays: Response Quantification and Entry Pathway Analysis

Description: Murine neuronal networks, derived from embryonic frontal cortex (FC) tissue grown on microelectrode arrays, were used to investigate zinc toxicity at concentrations ranging from 20 to 2000 mM total zinc acetate added to the culture medium. Continual multi-channel recording of spontaneous action potential generation allowed a quantitative analysis of the temporal evolution of network spike activity generation at specific zinc acetate concentrations. Cultures responded with immediate concentratio… more
Date: August 2007
Creator: Parviz, Maryam
open access

Construction of a Pseudomonas aeruginosa Dihydroorotase Mutant and the Discovery of a Novel Link between Pyrimidine Biosynthetic Intermediates and the Ability to Produce Virulence Factors

Description: The ability to synthesize pyrimidine nucleotides is essential for most organisms. Pyrimidines are required for RNA and DNA synthesis, as well as cell wall synthesis and the metabolism of certain carbohydrates. Recent findings, however, indicate that the pyrimidine biosynthetic pathway and its intermediates maybe more important for bacterial metabolism than originally thought. Maksimova et al., 1994, reported that a P. putida M, pyrimidine auxotroph in the third step of the pathway, dihydroorot… more
Date: August 2003
Creator: Brichta, Dayna Michelle
open access

Pyrimidine Genes in Pseudomonas Species

Description: This thesis is a comparative study of gene arrangements in Pseudomonas species, and is organized into three major sections. The first section compares gene arrangements for different pathways in Pseudomonas aeruginosa PAO1 to determine if the gene arrangements are similar to previous studies. It also serves as a reference for pyrimidine gene arrangements in P. aeruginosa. The second part compares the physical, and genetic maps of P. aeruginosa PAO1 with the genome sequence. The final secti… more
Date: December 2003
Creator: Roush, Wendy A.

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.
open access

Analysis of a Cotton Gene Cluster for the Antifungal Protein Osmotin

Description: Three overlapping genomic clones covering 29.0 kilobases of cotton DNA were found to encompass a cluster of two presumptive osmotin genes (OSMI and OSMII) and two osmotin pseudogenes (OSMIII and OSMIV). A segment of 16,007 basepairs of genomic DNA was sequenced from the overlapping genomic clones (GenBank Accessions AY303690 and AF304007). The two cotton osmotin genes were found to have open reading frames of 729 basepairs without any introns, and would encode presumptive osmotin preproteins o… more
Date: December 2003
Creator: Wilkinson, Jeffery Roland
open access

Bacterial Cyanide Assimilation: Pterin Cofactor and Enzymatic Requirements for Substrate Oxidation

Description: Utilization of cyanide as the sole nitrogen source by Pseudomonas fluorescens NCIMB 11764 (Pf11764) occurs via oxidative conversion to carbon dioxide and ammonia, the latter satisfying the nitrogen requirement. Substrate attack is initiated oxygenolytically by an enzyme referred to as cyanide oxygenase (CNO), which exhibits properties of a pterin-dependent hydroxylase. The pterin requirement for Pf11764 CNO was satisfied by supplying either the fully (tetrahydro) or partially (dihydro) reduced … more
Date: May 2004
Creator: Dolghih, Elena
open access

Isolation of a Pseudomonas aeruginosa Aspartate Transcarbamoylase Mutant and the Investigation of Its Growth Characteristics, Pyrimidine Biosynthetic Enzyme Activities, and Virulence Factor Production

Description: The pyrimidine biosynthetic pathway is an essential pathway for most organisms. Previous research on the pyrimidine pathway in Pseudomonas aeruginosa (PAO1) has shown that a block in the third step of the pathway resulted in both a requirement for exogenous pyrimidines and decreased ability to produce virulence factors. In this work an organism with a mutation in the second step of the pathway, aspartate transcarbamoylase (ATCase), was created. Assays for pyrimidine intermediates, and virule… more
Date: December 2004
Creator: Hammerstein, Heidi Carol
open access

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

Callus Development and Organogenesis in Cultured Explants of Cowpea (Vigna unguiculata (L.) Walp

Description: Cowpea, Vigna unguiculata (L.) Walp is an excellent source of protein, vitamins and minerals and a major food crop many parts of Africa. Optimal production levels are hampered by insect pests and diseases. Biotechnological techniques such as tissue culture and genetic engineering can aid in the development of varieties with resistance to insect pests and diseases. The objective of this study was to investigate conditions necessary for the development of a reproducible tissue culture system tha… more
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Date: December 2004
Creator: Omwenga, George Isanda
open access

Microsatellite-based genetic profiling for the management of wild and captive flamingo populations.

Description: Flamingo species generate tremendous interest whether they are small captive groups or wild populations numbering in the thousands. Genetic pedigrees are invaluable for maintaining maximum genetic diversity in captive, as well as wild, populations. However, presently there is a general lack of genetic data for flamingo populations. Microsatellites are loci composed of 2-6 base pair tandem repeats, scattered throughout higher eukaryotic genomes, often exhibiting high levels of polymorphism an… more
Date: December 2005
Creator: Kapil, Richa
open access

Impaired virulence factor production in a dihydroorotate dehydrogenase mutant (pyrD) of Pseudomonas aeruginosa.

Description: Previous research in our laboratory showed that when knockout mutations were created in the pyrB and pyrC genes of the pyrimidine pathway in Pseudomonas aeruginosa, not only were the resultant mutants auxotrophic for pyrimidines but they were also impaired in virulence factor production. Such a correlation had not been previously reported for P. aeruginosa, a ubiquitous opportunistic pathogen in humans. In an earlier study it was reported that mutants blocked in one of the first three enzymes … more
Date: December 2005
Creator: Ralli, Pooja

Isolation and Characterization of Polymorphic Loci from the Caribbean Flamingo (Phoenicopterus ruber ruber): New Tools for Wildlife Management

Description: Methods to determine genetic diversity and relatedness within populations are essential tools for proper wildlife management. Today the approach of choice is polymerase chain reaction-based microsatellite analysis. Seven new polymorphic loci were isolated from a microsatellite-enriched Caribbean flamingo genomic library and used to characterize survey populations of Caribbean and African greater flamingos. In addition, four of these loci were used to verify parentage relationships within a cap… more
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Date: December 2005
Creator: Preston, E. Lynn
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