Chemistry Commons^™

Structural Evidence For Rifampicin Monooxygenase Inactivating Rifampicin By Cleaving Its Ansa-Bridge, Li Kai Liu, Yumin Dai, Heba Abdelwahab, Pablo Sobrado, John J. Tanner

Chemistry Faculty Research & Creative Works

Rifampicin monooxygenase (RIFMO) decreases the potency of rifampicin (RIF) by converting it to oxidative products. Further decomposition of RIF has been observed in bacteria producing RIFMO and contributes to RIFMO-mediated drug resistance. Here we report the first crystal structure of RIFMO in complex with the hydroxylated RIF product. The 2.10 Å resolution structure reveals a breach of the ansa aliphatic chain of RIF between naphthoquinone C2 and amide N1. Our data suggest that RIFMO catalyzes the hydroxylation of RIF at the C2 atom followed by cleavage of the ansa linkage, which leads to inactivation of the antibiotic by preventing key …

Identification Of Significant E0 Strength In The 22+ → 21+ Transitions Of 58,60,62Ni, L. J. Evitts, A. B. Garnsworthy, T. Kibédi, J. Smallcombe, M. W. Reed, B. A. Brown, A. E. Stuchbery, G. J. Lane, T. K. Eriksen, A. Akber, B. Alshahrani, M. De Vries, M. S. M. Gerathy, J. D. Holt, B. Q. Lee, B. P. Mccormick, A. J. Mitchell, M. Moukaddam, Sharmistha Mukhopadhyay, N. Palalani, T. Palazzo, Erin E. Peters, Anthony Paul D. Ramirez, S. R. Stroberg, T. Tornyi, Steven W. Yates

Chemistry Faculty Publications

The E0 transition strength in the 2₂⁺ → 2₁⁺ transitions of ^58,60,62Ni have been determined for the first time following a series of measurements at the Australian National University (ANU) and the University of Kentucky (UK). The CAESAR Compton-suppressed HPGe array and the Super-e solenoid at ANU were used to measure the δ(E2/M1) mixing ratio and internal conversion coefficient of each transition following inelastic proton scattering. Level half-lives, δ(E2/M1) mixing ratios and γ-ray branching ratios were measured at UK following inelastic neutron scattering. …

Time-Dependent Efficiency Measurements Of Polymer Solar Cells With Dye Additives: Unexpected Initial Increase Of Efficiency, Kyle J. Bandaccari, Grace E. Chesmore, Mitchel Bugaj, Parisa Tajalli-Tehrani Valverde, Richard P. Barber Jr., Brian J. Mcnelis

Physics

We report the effects of the addition of two azo-dye additives on the time-dependent efficiency of polymer solar cells. Although the maximum efficiencies of devices containing different amounts of dye do not vary greatly over the selected concentration range, the time dependence results reveal a surprising initial increase in efficiency in some samples. We observe this effect to be correlated with a leakage current, although a specific mechanism is not yet identified. We also present the measured lifetimes of these solar cells, and find that variations in dye concentrations produce a small effect at most. Characterization of the bulk heterojunction …

Tuning The Hydrophobic Cores Of Self-Immolative Polyglyoxylate Assemblies, Bo Fan, Rebecca E. Yardley, John F. Trant, Aneta Borecki, Elizabeth R. Gillies

Chemistry Publications

Polyglyoxylates are a recently-introduced class of self-immolative polymers, that depolymerize to small molecules upon the cleavage of a stimuli-responsive end-cap from the polymer terminus. The incorporation of different pendant ester groups or other aldehyde monomers offers the potential to tune the polymer properties, but this remains largely unexplored. With the goal of tuning the self-assembly and drug-loading properties of polyglyoxylate block copolymers, we explored the polymerization and copolymerization of n-butyl glyoxylate, L-menthyl glyoxylate, and chloral with ethyl glyoxylate to form UV light-responsive polyglyoxylates. The resulting polymers were coupled to poly(ethylene glycol) to afford amphiphilic block copolymers. Self-assembly of the …

Reversibility Of The Catalytic Ketonization Of Carboxylic Acids And Of Beta-Keto Acids Decarboxylation, Alexey V. Ignatchenko, Andrew J. Cohen

Chemistry Faculty/Staff Publications

Decarboxylation of beta-keto acids in enzymatic and heterogeneous catalysis has been considered in the literature as an irreversible reaction due to a large positive entropy change. We report here experimental evidence for its reversibility in heterogeneous catalysis by solid metal oxide(s) surfaces. Ketones and carboxylic acids having 13C-labeled carbonyl group undergo 13C/12C exchange when heated in an autoclave in the presence of 12CO2 and ZrO2 catalyst. In the case of ketones, the carbonyl group exchange with CO2 serves as evidence for the reversibility of all steps of the catalytic mechanism of carboxylic acids ketonic decarboxylation, i.e. enolization, condensation, dehydration and …

Alkyne Combustion: Experimental And Computational Studies Of Formyl Radical Production, Matthew Charles Drummer

Theses and Dissertations

The United States consumed a total of 97.4 trillion BTUs of energy in 2016 with over 80% of that energy consumption source being fossil fuel combustion. Before a combustion reactions reaches its end products, a number of intermediate products form and may react with other abundant atmospheric species to form aerosol particles and acid rain, both of which have potentially negative impacts on both human-made structures and the natural environment.

In an effort to counteract the consequences of fossil fuel combustion, scientists are interested in understanding the reaction mechanisms of hydrocarbon combustion reactions to understand which intermediate products form and …

Syntheses, Raman Spectroscopy And Crystal Structures Of Alkali Hexa-Fluoridorhenates(Iv) Revisited, James Louis-Jean, Samundeeswari Mariappan Balasekaran, Dean Smith, Ashkan Salamat, Chien Thang Pham, Frederic Poineau

Chemistry and Biochemistry Faculty Research

The A2[ReF6] (A = K, Rb and Cs) salts are isotypic and crystallize in the trigonal space group type P\overline{3}m1, adopting the K2[GeF6] structure type. Common to all A2[ReF6] structures are slightly distorted octa­hedral [ReF6]2− anions with an average Re—F bond length of 1.951 (8) Å. In those salts, symmetry lowering on the local [ReF6]2− anions from Oh (free anion) to D3d (solid-state structure) occur. The distortions of the [ReF6]2− anions, as observed in their Raman spectra, are correlated to the size of the counter-cations.

Azamacrocyclic-Based Frameworks: Syntheses And Characterizations, Chavis Andrew Stackhouse

USF Tampa Graduate Theses and Dissertations

Research in metal-organic frameworks (MOFs) has risen greatly in recent decades Owing to their unequaled potential tunability and structural diversity. MOFs may be described as crystalline structures composed of metal cations or clusters of cations, commonly referred to as secondary building units (SBUs), and custom-designed organic ligands. The variety of structural motifs, ligands, and SBUs that may be incorporated promote the attainment of essentially countless potential MOFs and application in numerous areas of interest, such as gas adsorption, catalysis, gas separation, and sensing. Further functionalization of MOF materials by means of post-synthetic modification(PSM)33–37 of metal clusters or organic ligands, constructing …

From Florida To Antarctica: Dereplication Strategies And Chemical Investigations Of Marine Organisms, Matthew A. Knestrick

USF Tampa Graduate Theses and Dissertations

In the fight against disease and illness, nature has provided mankind some of our best therapeutics in the form of secondary metabolites. The plant, fungi and animal phyla inhabiting the Earth produce diverse and unique chemistry that can be used in our fight against disease. In the growing threat of drug resistance and pathogen evolution, the field of natural products chemistry strives to explore new biological and chemical diversity sources, and develop innovative methodology to identify and isolate new chemistry faster than ever.

The dissertation herein presented is one such effort to find new, bioactive chemistry from the marine environments. …

Synthesis Of Oxygenated Boronic Acid Substituted A-Cyanostilbenes For Use As Antibacterial, Yewon Kim

Honors Theses

Stilbenes are naturally occurring compounds that have exhibited antibacterial activity, although the biological effect of various stilbenes differs for Gram-positive and Gram-negative strains of bacteria. In prior research, cyanostilbenes have shown slight antibacterial activity (Brownlee, et al. 1943). This project aims to explore whether hybrid oxygenated a-cyanostilbenes possessing a boronic acid pharmacophore exhibits significant antibacterial activity (Das et al. 2013). The biological activity against Staphylocococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) was tested using the Kirby-Bauer text. No inhibition of E. coli growth was shown while S. aureus was partially inhibited.

Evaluating Mutagenicity Of Burned Arginine-Based Heterocyclic Amines And Anti-Mutagenicity Effect Of Chinese Medicinal Herbs, Rayford C. Alva

Honors Theses

From the unexpected finding that cooked grains and meat substitutes elicit a mutagenic response in Salmonella typhimurium TA98, our work has been aimed at deconstructing this finding via a survey of heated binary amino acid combinations, involving arginine, a plant-based amino acid. secondly, our work has looked towards sing phytochemical extracts from traditional Chinese medicinal herbs to inhibit the mutagenic activity of heterocyclic amines (main culprit for mutagenicity in meat). Two fractions from the burned products of arginine and phenylalanine (RF-HCA-06 and -07) were statistically significant inducers of mutagenesis; Scutellaria barbata and Oldenlandia diffusa, both separately and together, were statistically …

Temporal Changes In Dissolved Calcium In Stream And River Waters In Western Kentucky Watershed, Adam Martin

Scholars Week

Temporal Changes in Dissolved Calcium in Stream and River Waters in Western Kentucky Watershed

Effect Of Electron Withdrawing And Electron Donating Substituents On The Synthesis Of 1,3,4-Oxadiazoles Using Dibromotriphenylphosphorane, Emily Bliss

Undergraduate Distinction Papers

The goal of this project was to determine the effects that electron withdrawing and electron donating substituents have on the synthesis of 1,3,4-oxadiazoles using a hydrazide starting material and dibromotriphenylphosphorane. This investigation involved the synthesis of hydrazide starting material followed by the synthesis of the oxadiazole with electron donating, withdrawing, or neutral substituents. Through this study, one neutral, three electron donating, two electron withdrawing substituents were investigated. Reactions were analyzed through nuclear magnetic resonance spectroscopy. Neutral electronegative substituents were deemed to be more successful through their percent yield and nuclear magnetic resonance spectroscopy data than both electron donating and withdrawing …

Epoxy Phosphonate Ester As A Coupling Agent For Transition Metal And Metal Oxide Surfaces, Thomas P. Schuman

Chemistry Faculty Research & Creative Works

A method for surface modification of a substrate comprising surface oxide and/or hydroxy groups, with a compound comprising an ester group and an epoxy ring, wherein the epoxy group remains intact after the reacting. A method for surface modification of a substrate comprising surface oxide and/or hydroxy groups, with a compound comprising an ester group and a functionalized epoxy ring, wherein the functionalized epoxy group remains intact after the reacting. A composite material comprising surface-modified metal oxide nanoparticles dispersed within a polymeric material, wherein the surface modification comprises a compound comprising an ester group and an epoxy ring is also …

Workflows For X-Ray And Neutron Interferometry/Tomography As Applied To Additive Manufacturing, Jumao Yuan

LSU Doctoral Dissertations

Grating-based interferometry/tomography is being rapidly developed for non-destructive evaluation of additive manufacturing test articles. An application requiring an efficient workflow is extremely necessary for stress and fatigue testing samples.

At present, scientific workflows play an important role for computational experiments in additive manufacturing 3D printing and interferometry/tomography imaging analysis. A clear workflow template allows scientists to process experiments easier and faster. Work flow library grows, but to find an appropriate workflow for their task is challenging. In our research, there are mainly three portions in the workflow, interferometry analysis, image reconstruction and 3D visualization. Currently, the hierarchy of workflows in …

Characterization Of Nylon-12 In A Novel Additive Manufacturing Technology, And The Rheological And Spectroscopic Analysis Of Peg-Starch Matrix Interactions, Garrett Michael Craft

USF Tampa Graduate Theses and Dissertations

In this work differential scanning calorimetry, dynamic mechanical analysis, Fourier-Transformed Infrared Spectroscopy [FT-IR] and polarized light microscopy will be employed to characterize polymeric systems. The first chapter broadly covers polymer synthesis and important characterization methods.

In the second chapter, a polyamide (PA12) will be sintered via a novel additive manufacturing (AM) technology developed here at USF termed LAPS (Large Area Projection Sintering). LAPS uses extended sintering timespans to ensure complete melting and densification of the polymer powder over the entire two-dimensional area of the part’s footprint. Further, it allows for the printed layer to crystallize and shrink in its entirety …

Eating Crickets? Nutrient Mineral Content Of Two Cricket Species And Chapul Cricket Protein Bars Using Mp-Aes, Nathan Hopkins

Student Scholar Showcase

Global agriculture is beset by numerous challenges which must be surmounted to feed a developing world, from combating climate change to the cultivation of sustainable food products. This, in addition to protein and nutrient deficiencies in the developing world, makes considering alternative protein sources, such as a crickets, an attractive option. Crickets use a fraction of the land and water that protein sources like beef cattle do, and can be cultivated in urban environments in stacked boxes. This research investigation aims to quantify the nutrient mineral content (Iron, Sodium, Potassium, Calcium, and Magnesium) of two cricket species (Acheta domesticus …

Elemental Analysis Of Beer Manufactured In Virginia Satellite Breweries, Jennifer Wiliams

Student Scholar Showcase

Financial incentives from the state and wider distribution potential have lured many west coast brewers to open satellite breweries in Virginia. Quality control is crucial for any brewery and especially important in satellite breweries that need to imitate the standard set by the parent brewery. Zinc, magnesium, iron, sodium manganese, and calcium are trace elements found in wort and are essential for enzymes that catalyze fermentation reactions. These elements protect against cell stress, play a crucial role in flocculation, and can affect the flavoring and coloration of beer. Barley, water, and hops are the sources of these elements in beer. …

Elastin-Like Polypeptide Fusion Tag As A Protein-Dependent Solubility Enhancer Of Cysteine-Knot Growth Factors, Tamina L. Johnson

USF Tampa Graduate Theses and Dissertations

Elastin-like peptide (ELP) fusions promote therapeutic delivery and efficacy. Recombinant proteins, like neurotrophins, lack bioavailability, have short in vivo half-lives, and require high manufacturing costs. Fusing recombinant proteins with genetically encodable ELPs will increase bioavailability, enhance in vivo solubilization, as well as provide a cost-effective method for purification without the need for chromatography. During expression of neurotrophin-ELP (N-ELP) fusions, dense water-insoluble aggregates known as inclusion bodies (IBs) are formed. Inclusion bodies are partially and misfolded proteins that usually require denaturants like Urea for solubilization. Strong denaturants arrest ELPs stimuli-responsive property and increase unwanted aggregation, making purification difficult, yet possible. The …

Metabolism-Driven High-Throughput Cancer Identification With Glut5-Specific Molecular Probes, Srinivas Kannan, Vagarshak Begoyan, Joseph Fedie, Shuai Xia, Łukasz J. Weseliński, Marina Tanasova, Smitha Rao

Michigan Tech Publications, Part 1

Point-of-care applications rely on biomedical sensors to enable rapid detection with high sensitivity and selectivity. Despite advances in sensor development, there are challenges in cancer diagnostics. Detection of biomarkers, cell receptors, circulating tumor cells, gene identification, and fluorescent tagging are time-consuming due to the sample preparation and response time involved. Here, we present a novel approach to target the enhanced metabolism in breast cancers for rapid detection using fluorescent imaging. Fluorescent analogs of fructose target the fructose-specific transporter GLUT5 in breast cancers and have limited to no response from normal cells. These analogs demonstrate a marked difference in adenocarcinoma and …

Reaction Of Formation Of Difurfurilidenacetone – Difa, M. Axmadaliev

Scientific journal of the Fergana State University

Reaction of formation of difurfurilidenacetone – DIFA

Problems Of Providing The Population With Quality Fat And Oil Products, A. Ibragimov,, R. Karabayeva

Scientific journal of the Fergana State University

Problems of providing the population with quality fat and oil products

Reaction Of Formation Of Difurfurilidenacetone – Difa, M. Axmadaliev

Scientific journal of the Fergana State University

Reaction of formation of difurfurilidenacetone – DIFA

Problems Of Providing The Population With Quality Fat And Oil Products, A. Ibragimov,, R. Karabayeva

Scientific journal of the Fergana State University

Problems of providing the population with quality fat and oil products

An Integrated Approach To Studying And Engineering Bacterial Type Ii Polyketide Core Structure Biosynthesis, Xuechen Zhu

Chemistry and Chemical Biology ETDs

Natural products including alkaloids, phenylpropanoids, polyketides, terpenoids and antibiotics provide abundant resources for drugs and drug leads. Type II polyketides (PK-IIs) are a large array of aromatic polyketides that have exhibited various bioactivities including anti-tumor, anti-cancer, anti-fungal and anti-bacteria. Based on the lengths of carbon chains and the cyclization patterns in their core structures, most bacterial PK-IIs have been classified into 6 typical classes: benzoisochromanequinone (BIQ), anthracycline (ANT), angucycline (ANG), tetracycline (TET), tetracenomycin (TCM) and pentangular (PEN). Bioengineering for diversification of PK-II core structures will generate libraries of bioactivities, which can serve the drug discovery in this family of compounds. …

Effects Of Enhanced Efficiency Nitrogen Fertilizers On Agronomic Parameters And Loss Pathways In The Subtropical Mississippi Delta Region, Scott Michael Pensky

LSU Master's Theses

Minimizing nitrogen (N) loss is critical for improving N use efficiency (NUE) in crop production and reducing its effects on the environment. Management practices such as seasonal application timing of N fertilizers and the addition of enhanced efficiency N fertilizers (EENFs) were investigated for the high N requirement of the two most common cereal crops globally, corn (Zea mays L.) and wheat (Triticum aestivum L.), in the subtropical climate of Louisiana. Field research was established during the 2016 and 2017 seasons at the LSU Agricultural Center’s Dean Lee and Central research stations to examine the effect of different EENFs and …

Evaluation Of Controlled-Release Nitrogen And Potassium Fertilizer In Louisiana Sugarcane Production, Samuel Kwakye

LSU Master's Theses

Sugarcane (Saccharum spp) production is an integral part of Louisiana's economy. Proper fertilizer management, particularly nitrogen (N) and potassium (K), optimizes sugarcane production. An experiment was established in 2015 at the LSU AgCenter Sugar Research Station in St. Gabriel, Louisiana to: (1) assess the effect of N and K fertilizer sources on sugarcane yield and quality parameters, and (2) monitor the changes in inorganic N and K levels in the soil at different sugarcane growth stages. The experiment was arranged in a randomized complete block design on a Sharkey clay soil and complete randomized design on a Commerce …

Characterization Of Polymers Containing Ferrocene And Imidazole With Density Functional Theory, Eric Mullins

Electronic Theses & Dissertations

Electrochemical and UV-Vis studies on these polymers in the presence of aqueous solutions containing metal ions have revealed significant modifications in the electrochemical properties and absorption spectra. These modifications in electrochemical properties could be attributed to the ability of the imidazole to coordinate with metal ions, increasing its electron deficiency and enhancing oxidization of the nearby ferrocene moiety if it is in close proximity with imidazole. However, the mechanism of interaction between the imidazole and metal ions, as well as the equilibrium geometry of the resulting polymer-metal ion complex is unknown.

In this thesis, density functional theory (DFT) was used …

Synthesis Of Novel Agents For The Treatment Of Infectious And Neurodegenerative Diseases, Benjamin Joe Eduful

USF Tampa Graduate Theses and Dissertations

Infectious and neurodegenerative diseases continue to be a major concern worldwide. In spite of the great advances in drug therapy for treating various infectious and neurodegenerative diseases, there is still an urgent need for new and improved drugs due to increasing drug resistance among pathogens, emergence of new pathogens, ease of transmission of infections, ineffective available treatments, toxicity associated with current standard of care, aging populations and the lack of better alternative treatment options.

The first part of this manuscript (chapters 1 - 5) describes the synthesis of novel agents active against Leishmania donovani. According to the World Health Organization …

The Preparation Of Diaryliodonium Salts For Application In Arylation Chemistry, Thomas Ludwig Seidl

Dissertations and Theses

Diaryliodonium salts offer potential as novel reagents for arylation chemistry. An overall goal and successful outcome of this work has been to further understanding of diaryliodonium salt chemistry by developing practical methods that enable chemists more convenient access to these reagents, for the purpose of reaction development. To this end a robust and convenient preparation method has been developed and resulted in novel commercially available diaryliodonium salts. The remainder of the work described, has focused on understanding the parameters important to diaryliodonium mediated arylation and has resulted in a solid framework that multiple future development efforts can build upon.

A …