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Identification Of The Functional Regions Of The Yeast Activator Adr1, Lynne Taylor Bemis

Doctoral Dissertations

ADR1, a transcriptional activator from the yeast Saccharomyces cerevisiae, is required for activation of the glucose-repressible alcohol dehydrogenase, ADH II (encoded by the ADH2 gene). The ADR1 gene encodes a protein which binds to an upstream activation sequence in the ADH2 promoter. Several methods were used to locate functional regions of the ADR1 protein.

The adr1-1 mutation was identified as a C to G transversion resulting in a nonsense codon at the eleventh codon of ADR1. tRNA-suppressors which substituted an amino acid at the eleventh codon of adr1-1 resulted in a functional adr1-1 protein, indicating that the translational start of …

The Effect Of Reagent Rotation On Gas Phase Reactions, Judith Agnes Harrison

Doctoral Dissertations

This dissertation examines the effect of reagent rotation in elementary gas phase reactions. Historically, the effect of rotational excitation of the reagents of a chemical reaction on the reactive cross section has been poorly understood. One of the major reasons for this was the lack of a simple model in which the dynamics could be visualized. In this work, such a model is developed and utilized in order to elucidate trends in reactivity observed upon rotational excitation. Within the context of this model, exact quantum mechanical scattering calculations are performed for a simple atom-diatom system. These exact quantum mechanical probabilities …

Remote In-Situ Detection Of 2,4,6-Trinitrotoluene And Other Explosives Using Fiber Optics, Yunke Zhang

Doctoral Dissertations

The goal of this research was to develop methods for the in-situ determination of 2,4,6-trinitrotoluene (TNT) and other polynitroaromatic compounds in groundwater. The first approach was to use an adsorbent to preconcentrate TNT for direct determination. Poly(vinyl alcohol) was crosslinked with glutaraldehyde to form a clear gel that is transparent into the ultraviolet. The volume and swelling of the gel can be controlled by varying the amount of glutaraldehyde. The coefficient for TNT partitioning between the gel and water is 1.4. The gel offers important advantages as a matrix for chemical sensor development, but is not suitable for determining TNT …

Synthesis And Reactions Of Phosphonito Polymetallic Complexes And Halogen Oxidation Of Cyclo-Tetraphosphoxane Molybdenum Cage Complexes, Carmen Valdez

Doctoral Dissertations

Mixed-valent tetrametallic complexes of the type Mo$\sb2\lbrack$M(CO)$\sb4$(PhPO$\sb2$)$\sb2\rbrack\sb2\sp{4-}$ (M = Cr, Mo, W) were synthesized by the nucleophilic attack of the phosphonito metallo-ligand cis-M(CO)$\sb4$(PhPO$\sb2$)$\sb2\sp{4-}$ on dimolybdenum tetraacetate. These complexes were characterized by elemental analyses and NMR, IR, and UV-Vis spectroscopy. The x-ray crystal structure for the tetra-molybdenum complex indicates a M-M bondlength of 2.186(2). Only weak interactions were found with potential axial ligands such as amines, phosphines and isonitriles. Oxidation with four equivalents of iodine occurred at the Mo(O) sites yielding Mo$\sb2\lbrack$Mo(CO)$\sb3$I$\sb2$(PhPO$\sb2$)$\sb2\rbrack\sb2\sp{4-}$ with new seven-coordinate Mo(II) sites. The phosphorus-31 NMR spectrum of this complex exhibits temperature-dependent behavior indicating rapid geometric isomerization …

Characterization Of Cell Cycle Changes In Polyamine-Depleted Hela Cells, Robert Anthony Koza

Doctoral Dissertations

HeLa cells were synchronized for S-phase DNA synthesis and simultaneously depleted of polyamines by the addition of the inhibitor of polyamine biosynthesis, $\alpha$-difluoromethylornithine (DFMO).

DFMO reacts catalytically with and irreversibly inhibits the enzyme ornithine decarboxylase (ODC) thereby preventing the biosynthesis of the polyamines putrescine, spermidine, and spermine.

The depletion of polyamines in HeLa cells inhibits cellular processes such as DNA synthesis and proliferation. These processes could be reversed by the addition of spermidine 10-12 hours before S-phase DNA synthesis was initiated.

Nuclear reconstitution procedures were utilized to determine the location of the deficiency in polyamine-depleted cell nuclei. It was shown …

Ring-Chain Tautomerism Studies In 2-(2-Hydroxyethoxy)-Benzaldehydes And 2-(5-Hydroxy-3-Oxa-Pentyloxy)-Benzaldehydes, Adam John Jaglowski

Doctoral Dissertations

The synthesis, characterization and ring-chain tautomerism studies of substituted 2-(2-hydroxyethoxy)-benzaldehydes and 2-(5-hydroxy-3-oxa-pentyloxy)-benzaldehydes are described. The benzaldehydes, substituted in the 3-, 5- or 3,5-positions with either nitro, bromo, chloro, iodo, phenyl or methyl groups, were studied by proton and carbon-13 Nuclear Magnetic Resonance spectroscopy as a means of determining their potential to exist as ring-chain tautomeric mixtures. The 2-(5-hydroxy-3-oxa-pentyloxy)-benzaldehydes and 5-substituted 2-(2-hydroxyethoxy)-benzaldehydes exist solely as the chain tautomers in solution, while 3- and 3,5-substituted 2-(2-hydroxyethoxy)-benzaldehydes are mixtures of ring and chain tautomers in solution. A correlation of K with substituents indicates that the size of the aromatic substituent in the 3-position …

Development Of A Glucose Sensor Based On Competitive Binding And Laser-Excited Fluorescence, Richard William Bauer

Doctoral Dissertations

An optical glucose sensor has been developed using competitive binding in conjunction with energy transfer. Sensor response is based on competition between glucose and dextran for a limited number of binding sites on the protein concanavalin A (conA). The system is optically monitored using fluorescent donor-acceptor dye pairs labeled to concanavalin A and dextran. When the dyes are sufficiently close, on the order of 50 A, energy is transferred from the donor emission band to the overlapping excitation band of the acceptor. This nonradiative, singlet-singlet transfer of energy enhances the acceptor emission at the expense of donor emission.

In absence …

Solvatochromic Indicators For Fiber Optic Chemical Sensors, Ziad Munib Shakhsher

Doctoral Dissertations

The goal of this thesis was to develop and evaluate solvatochromic indicators for fiber optic chemical sensors. Interaction with analyte modifies the polarity of the immobilized indicator environment leading to a shift in their fluorescence spectra. Three systems were studied.

In the first study a cationic fluorescent probe, 5-dimethylaminonaphthalene-1-sulfonamidoethyltrimethylammonium ion (DA$\sp+$), was equilibrated with unmodified- and hydrocarbon bonded-silicas. In solution and unmodified silica, maximum DA$\sp+$ fluorescence shifts to longer wavelengths with increasing percentages of methanol, tetrahydrofuran and acetonitrile in water. On hydrocarbon bonded silicas, however, DA$\sp+$ emission maxima in water occur at shorter wavelengths indicating a very nonpolar environment. This …

Development Of An Analytical Method For The Determination Of Extractable Nitroaromatics And Nitramines In Soils, Thomas F. Jenkins

Doctoral Dissertations

An analytical method was developed to determine the concentrations of HMX, RDX, TNB, DNB, tetryl, TNT and 2,4-DNT in soil. The method relies on solvent extraction with analysis by reversed-phase liquid chromatography.

The extraction step was studied in terms of process kinetics and recovery. Two solvents (acetonitrile and methanol) and four extraction techniques (Soxhlet, ultrasonic bath, mechanical shaker and homogenizer-sonicator) were compared. Ultrasonic bath extraction with acetonitrile was selected based on extraction kinetics, overall analyte recovery, sample throughput, and instability of analytes at elevated temperature. The rate of extraction of analytes from field-contaminated soil was shown to be much slower …

The Synthesis And Characterization Of Transition Metal Complexes Of Triazacyclododecane And Its Tri-N-Methyl And Orthoamide Derivatives, Steven Paul Vankouwenberg

Doctoral Dissertations

The comparative study of the mono- and tricyclic triamine complexes based on twelve-membered rings and the group 6 and group 10 metals has been initiated. The four ligands used in this study were 1,5,9-triazacyclododecane ( (12) aneN$\sb3$), 1,5,9-trimethyl-1,5,9-triazacyclododecane (Me$\sb3$ (12) aneN$\sb3$), 1,5,9-triazacyclododecane orthoformamide (orthoformamide) and 1,5,9-triazacyclododecane orthoacetamide (orthoacetamide). Complexes with zero-valent group 6 metal (Cr, Mo, W) tricarbonyls were characterized and the single-crystal X-ray structures determined for each ligand-molybdenum tricarbonyl complex. Complexes with nickel(II), palladium(II) and platinum(IV) have been characterized and the single-crystal X-ray structure of orthoacetamide PdCl$\sb2$ has been determined. The tricyclic orthoamides have been found to be less …

Deoxyribonucleases Expressed In Competence-Induced Com And Spo0 Mutants Of Bacillus Subtilis, Billy Robert Mcgrew

Doctoral Dissertations

The inclusion of 1% casein in buffer used to reactivate enzymes subjected to SDS-polyacrylamide electrophoresis resulted in faster and more complete restoration of nuclease and B-galactosidase enzyme activities. Enzyme activities which were absent from gels during longer wash procedures were detectable with this technique. The threshold of detection of two-dimensionally separated Deoxyribonuclease I was 1 picogram, tenfold lower than for previously reported wash procedures. Addition of BSA at concentrations above 50 ug/ml to nuclease gels was found to result in less effective detergent removal during wash procedures and reduced recovery of enzyme activity.

General and specific nuclease expression patterns were …