Digital Commons Network^™

New Biologically Active Compounds From Kenyan Propolis, Assya Petrova, Milena Popova, Christina Kuzmanova, Iva Tsvetkova, Hristo Naydenski, Eliud Muli, Vassya Bankova

All Peer-Reviewed Publications

From propolis samples from Kenya, two new arylnaphtalene lignans were isolated, tetrahydrojusticidin B 1 and 6-methoxydiphyllin 2, along with four known phenolic compounds 5-8, found for the first time in propolis. The structures of the compounds were elucidated based on their spectral properties. The geranylstilbenes 7 and 8 demonstrated antibacterial activity against S. aureus, and the geranylflavon macarangin 6 possessed antiradical activity against DPPH radicals. © 2010 Elsevier B.V. All rights reserved.

Applications Of Molecular Dynamics Techniques And Spectroscopic Theories To Aqueous Interfaces, Anthony Green

USF Tampa Graduate Theses and Dissertations

The primary goal of spectroscopy is to obtain molecularly detailed information about the system under study. Sum frequency generation (SFG) vibrational spectroscopy is a nonlinear optical technique that is highly interface specific, and is therefore a powerful tool for understanding interfacial structure and dynamics. SFG is a second order, electronically nonresonant, polarization experiment and is consequently dipole forbidden in isotropic media such as a bulk liquid. Interfaces, however, serve to break the symmetry and produce a signal. Theoretical approximations to vibrational spectra of O-H stretching at aqueous interfaces are constructed using time correlation function (TCF) and instantaneous normal mode (INM) …

Design, Combinatorial Synthesis, And Biological Evaluation Of Novel Α-Helical Mimetics Based On Functionalized Piperazines As Antagonists Of P53/Mdm2 Interactions, Melissa Elizabeth Topper

USF Tampa Graduate Theses and Dissertations

The p53 protein promotes tumor eradication upon activation, making it an attractive target in cancer therapies. A reported 50% of all human cancers display aberrant activation of the MDM2 oncoprotein, which directly promotes tumorgenesis by inactivating the transcriptional activity of wild type p53, and is commonly associated with drug, chemo, and radio therapy resistance. Previously reported crystallographic analysis of the p53/MDM2 complex infers that the p53 protein forms a 2.5 turn amphipathic alpha helix whose hydrophobic face interacts within a deep hydrophobic cleft in the NH2-terminal domain of the globular MDM2. This suggests that the synthesis of small molecular antagonists …

Design And Combinatorial Synthesis Approach Of Non-Peptidic Trimeric Small Molecules Mimicking I, I + 4(3), I + 7 Positions Of Alpha-Helices, Mingzhou Zhou

USF Tampa Graduate Theses and Dissertations

Protein-protein interactions are key to several biological processes that facilitate signal transduction and many other processes. These interactions are involved in pathways that are critical to many human diseases. Targeting specific protein-protein interactions is a challenging goal because protein-protein interactions are predominately through hydrophobic interactions. Antagonists of the protein-protein interactions need to be perfectly fit into the binding pockets to ensure the activity. The -helical domain of the proteins behaves as the recognition motifs for numerous protein-protein, and protein-nucleic acid interactions. Research has shown that pathways of many diseases contain protein-protein interactions involving -helical domains, e.g. neurological disorders, bacterial infections, …

Frataxin And Mitochondrial Fes Cluster Biogenesis, Timothy L. Stemmler, Emmanuel Lesuisse, Debumar Pain, Andrew Dancis

Biochemistry and Molecular Biology Faculty Publications

Friedreich’s ataxia is an inherited neurodegenerative disease caused by frataxin deficiency. Frataxin is a conserved mitochondrial protein that plays a role in Fe-S cluster assembly in mitochondria. Fe-S clusters are modular cofactors that perform essential functions throughout the cell. They are synthesized by a multi-step and multi-subunit mitochondrial machinery that includes a scaffold protein Isu for assembling a protein bound Fe-S cluster intermediate. Frataxin interacts with Isu, iron, and with the cysteine desulfurase Nfs1 that supplies sulfur, thus placing it at the center of mitochondrial Fe-S cluster biosynthesis.

Novel Polymer Coupling Chemistry Based Upon Latent Cysteine-Like Residues And Thiazolidine Chemistry, Jospeh S. Carlson, Megan R. Hill, Taiga Young, Philip Costanzo

Chemistry and Biochemistry

Chain end functional polymers were prepared via reversible addition–fragmentation transfer (RAFT) polymerization techniques that were further chain extended with acrylonitrile. Under reducing conditions, latent cysteine-like residues were exposed at the chain ends. A variety of reduction conditions were explored and base polymers were then tethered together via thiazolidine chemistry.

Integrated Affinity Column Capillary Electrophoresis Microdevices For Biomarker Analysis, Weichun Yang

Theses and Dissertations

In this dissertation, microfluidic systems that integrate antibody-based sample preparation methods with electrophoretic separation are developed to analyze multiple biomarkers in a point-of-care setting. To form an affinity column, both monolith materials and wall-coated channels were explored. I successfully demonstrated that monolith columns can be prepared in microfluidic devices via photopolymerization. The selectivity of monolith columns was improved by immobilizing antibodies on the surface. These affinity columns can selectively enrich target analytes and reduce the signal of contaminant proteins up to 25,000 fold after immunoaffinity extraction. These results clearly demonstrate that microchip affinity monoliths can selectively concentrate and purify target …

Trans-Excision-Splicing Ribozyme And Methods Of Use, Stephen M. Testa, Michael A. Bell

Chemistry Faculty Patents

A group I intron-derived ribozyme which binds RNA in trans, excises an internal segment from within the RNA, and splices the remaining 5′ and 3′ ends of the RNA back together (the trans-excision-splicing reaction) is disclosed. The excised segment can be as long as 28 nucleotides, or more, and as little as one nucleotide. The ribozymes of the invention are easily modified to alter their sequence specificity. Such ribozymes represent a new and potentially powerful class of generally adaptable genetic therapeutics.

Functional, Degradable Polyester Materials Synthesized From Poly(Epsilon-Caprolactone-Co-2-Oxepane-1,5-Dione): An Investigation Into The Derivatization, Self Assembly, And Degradation Behavior Of Poly(Epsilon-Caprolactone)-Based Materials, Rhiannon K. Iha

Arts & Sciences Graduate Student Theses and Dissertations

Biocompatible, degradable polymers possessing a high degree of complexity are an extremely desirable target for many applications. In order to further develop the range and utility of materials made from aliphatic polyesters, poly(epsilon-caprolactone-co-2-oxepane-1,5-dione) (P(CL-co-OPD)) was used as a polymeric precursor for the construction of a series of functional polyester-based materials. By taking advantage of the electrophilic ketone moieties characteristic of the OPD repeat unit, small molecule and polymer grafts were attached to the PCL backbone through the formation of both hydrazone and ketoxime ether linkages. This work has focused on both the synthesis and characterization of functional, degradable polyesters, including …

Synthesis And Characterization Of An Oligothiophene-Ruthenium Complex And Synthesis And Optical Properties Of Oligothiophene-Ruthenium Complexes Bound To Cdse Nanoparticles, Nathan A. Bair

Theses and Dissertations

Oligothiophenes are of increasing interest in organic based electronic devices in part due to their high electron and hole mobilities. In an organic photovoltaic (OPV) device, the electronic properties of oligothiophenes make them advantageous as charge transfer junctions. To serve as charge transfer junctions, oligothiophenes must be functionalized to bind to the donor and acceptor parts of the device. The donor and acceptor parts are different materials and the synthesis of asymmetric oligothiophenes is of great interest. Previous researchers in our lab synthesized four asymmetric oligothiophenes, two with two thiophene subunits and two with four. Each set of oligothiophenes contained …

Aspergillus Fumigatus Sida Is A Highly Specific Ornithine Hydroxylase With Bound Flavin Cofactor, Samuel W. Chocklett, Pablo Sobrado

Chemistry Faculty Research & Creative Works

Ferrichrome is a hydroxamate-containing siderophore produced by the pathogenic fungus Aspergillus fumigatus under iron-limiting conditions. This siderophore contains N5-hydroxylated l-ornithines essential for iron binding. A. fumigatus siderophore A (Af SidA) catalyzes the flavin- and NADPH-dependent hydroxylation of l-ornithine in ferrichrome biosynthesis. Af SidA was recombinantly expressed and purified as a soluble tetramer and is the first member of this class of flavin monooxygenases to be isolated with a bound flavin cofactor. The enzyme showed typical saturation kinetics with respect to l-ornithine while substrate inhibition was observed at high concentrations of NADPH and NADH. Increasing amounts of hydrogen peroxide were measured …

Synthesis Of Bis-Styrylbenzene Derivatives Via Wittig-Horner Reaction, Joseph K. Wray, Tae Soo Jo, Pradip K. Browmik

Undergraduate Research Opportunities Program (UROP)

Alzheimer’s Disease is now one of the most common diseases affecting the elderly population. Recently, bis-styrylbenzene derivatives have been shown to reduce the formation of Beta-amyloid plaques in the brain which are profoundly correlated with this disease. Finding new biologically active compounds which can reduce or prevent Alzheimer’s Disease has drawn much attention over the past few decades. Georg Wittig, Nobel Prize Winner in Chemistry, 1979.

Undergraduate Research Opportunities Program 2010, University Of Nevada, Las Vegas

Undergraduate Research Opportunities Program (UROP)

The Undergraduate Research Opportunities Program (UROP) cultivates and supports research partnerships and invites undergraduates to work as the junior colleagues of faculty. The program offers the opportunity to work on cutting edge research—whether you join established research projects or pursue your own ideas. As participants, undergraduates engage in each phase of standard research activity: developing research plans, writing proposals, conducting research, analyzing data. and presenting research results in oral and written form. The projects take place over the summer, and research can be done in any academic department or interdisciplinary laboratory. Projects can last for an entire semester, and many …

Synthesis, Kinetic And Photocatalytic Studies Of Porphyrin-Ruthenium-Oxo Complexes, Yan Huang

Masters Theses & Specialist Projects

Macrocyclic ligand-complexed transition metal-oxo intermediates are the active oxidizing species in a variety of important biological and catalytic oxidation reactions. Many transition metal catalysts have been designed to mimic the predominant oxidation catalysts in Nature, namely the cytochrome P450 enzymes. Ruthenium porphyrin complexes have been the center of the research and have successfully been utilized, as catalysts, in major oxidation reactions such as the hydroxylation of alkanes. This study focuses on kinetic and photocatalytic studies of oxidation reactions with wellcharacterized high-valent ruthenium-oxo porphyrin complexes.
The trans-dioxoruthenium(VI) porphyrins have been among the best characterized metal-oxo intermediates and their involvement as …

High Pressure Liquid Chromatography Studies Of The Reaction Of Platinum Complexes With Peptides, Khaja Muneeruddin

Masters Theses & Specialist Projects

Platinum complexes (cisplatin, carboplatin and oxaliplatin) are effective anticancer agents. However the major drawbacks of platinum chemotherapy are toxic side effects and resistance. The affinity of platinum complexes to sulfur donor ligands of side chains of methionine and cysteine amino acids was assumed to be responsible for toxicity and resistance. Recently, it was found that the reaction of platinum complex with proteins containing sulfur donor ligands could actually favor its anticancer activity. Copper transporter 1 (Ctr 1), a protein involved in the transport of copper into the cell, also helps in the influx of cisplatin by binding to N-terminal domain …

Exploring Zirconia As A Column Packing Material, Tushar Ghugare

Masters Theses & Specialist Projects

Zirconia is one of the most promising column packing materials for High Performance Liquid Chromatography (HPLC). The perfect HPLC support material should be energetically homogenous, have a high surface area on which different chemical species can reversibly attach and be physically and chemically stable over a wide range of pH, temperature and solvent conditions. Most existing supports do not have all of these properties. This project is also focused on a proteomics study. Zirconia, hafnium oxide and titanium oxide which are some of the more promising materials currently available, can be used for the separation and analysis of phosphorylated proteins. …

Isu Chem-Letter, Fall 2010, Illinois State University, Department Of Chemistry

Chem Letter

Newsletter of the Illinois State University Department of Chemistry

52nd Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 52nd annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Snowmass, Colorado, August 1-5, 2010.

Design, Synthesis, And Polymerization Of Novel Heterocyclic Monomers As Precursors For Functional Polyester, Poly(Ester Amide)S And Polyamides, Eylem Tarkin-Tas

Dissertations

The research presented in this dissertation involves the synthesis and polymerization of heterocyclic monomers which pave the way to biodegradable polyester nanocomposites, functional polyesters or poly(ester amide)s, functional polyamides and supramolecular polymers. The key monomers are ε-caprolactone, γ-acetamido-ε- caprolactone, γ-ethylene ketal-ε-caprolactam and α-amino-ε-caprolactam.

Poly(ε-caprolactone) organo-modified montmorillonite nanocomposites were prepared by in-situ polymerization using dibutyltin dimethoxide as initiator/catalyst. The montmorillonite was first modified with 1-decyl-2-methyl-3-(11-hydroxyundecyl)- imidazolium cation. The hydroxyl functionality was used for not only initiating polymer chains from the surface of the clay platelets but also for grafting polymer chains to the surface by acting as a reversible chain transfer …

Study On Energy Absorption Behaviors Of Hydrophobic Mesoporous Materials, Zhongyuan Sun

Theses and Dissertations - UTB/UTPA

Nanoporous energy absorption system has been developed tremendously as an advanced energy storage system in recent years. This research is to optimize the mesoporous energy absorption matrixes via surface treatment to find out the optimum conditions for higher energy conversion efficiency. Five mesoporous silica matrixes with pore size in a range of 3 to 31.6 nm were investigated. Six alkylchlorosilanes were used as the modification reagents. The results showed that the energy absorption density via pressure-induced infiltration is as high as 8.0 J/g which is 100 times larger than that of conventional energy absorption materials. The controllability of the energy …

Noninvasive, In-Vivo, Tissue Modulated Near Infrared Spectroscopy Of Fingertips: Resonance Raman Spectrum Of Human Hemoglobin, Bin Deng, Jerry Goodisman, George Shaheen, Rebecca J. Bussjager, Joseph Chaiken

Chemistry - All Scholarship

Tissue modulation refers to using external stimuli such as mechanical pressure and temperature to produce various spatiotemporal distributions of blood and conceivably other fluids in tissues. Having the capacity to execute tissue modulation¹ allows forms of difference spectroscopy to be used to isolate spectroscopic signals from specific components of the tissues noninvasively and in vivo. In the case of human fingertips we can think of the tissues present in the probed volume as being static tissue, plasma and red blood cells (RBCs). Static tissues deform under mechanical pressure based tissue modulation and the only possible fluid motions2 involve plasma …

Theoretical And Experimental Studies In Nuclear Magnetic Resonance, Adrienne M. Roehrich

Department of Chemistry: Dissertations, Theses, and Student Research

Nuclear magnetic resonance (NMR) is a tool used to probe the physical and chemical environments of specific atoms in molecules. This research explored small molecule analogues to biological materials to determine NMR parameters using ab initio computations, comparing the results with solid-state NMR measurements. Models, such as dimethyl phosphate (DMP) for oligonucleotides or CuCl for the active site of the protein azurin, represented computationally unwieldy macromolecules. ³¹P chemical shielding tensors were calculated for DMP as a function of torsion angles, as well as for the phosphate salts, ammonium dihydrogen phosphate (ADHP), diammonium hydrogen phosphate, and magnesium dihydrogen phosphate. The …

Isotropic And Anisotropic Metallic And Bimetallic Nanoparticles And Their Potential Applications In Biology, Minghong Liu

Dissertations

The development of synthetic procedures that produce nanoscale materials with controlled morphology is a significant area of investigation in nanotechnology. We have developed new synthetic procedures for fabrication of isotropic and/or anisotropic nanomaterials composed of palladium, ruthenium, nickel and alloys of palladium-ruthenium. The nanomaterials were fully characterized and were found to display unique size dependent properties. The electrochemical properties of isotropic palladium, ruthenium and palladium-ruthenium nanoparticles were investigated and the results showed that the particles were capable of charge storage and charge transfer on demand. Anisotropic palladium, ruthenium and palladium ruthenium nanoparticles were also fabricated and fully characterized. The nanoparticles …

Gold Nanoparticle - Modified Zinc Oxide Nanoparticles As Novel Photocatalytic Materials, Nayane Udawatte

Dissertations

The current study entails the construction of a novel nano-composite catalyst based on ZnO and Au nanoparticles and demonstrates its distinctive photocatalytic characteristics. Monodisperse gold nanoparticles (GNPs) passivated with monolayers of tiopronin or glutathione were synthesized via facile methods, and they were assembled on ZnO nanoparticles to form the nanocatalyst.

Steady state and time resolved photoluminescent studies on the nanocomposite revealed interesting charge transfer characteristics within the nanocomposite. Enhanced photooxidation of rhodamine 6G was observed for the nano-composite over bare ZnO, and modulation of photoactivity with the extent of GNP loading was illustrated. Photoreduction of thionine over the nanocomposite was …

Aryl Boronic Acid Inhibition Of Synthetic Melanin Polymerization, Jason M. Belitsky

Faculty & Staff Scholarship

Inhibitors of melanin formation are sought after for a range of applications. Boronophenylalanine is known to inhibit melanogenesis via boronic acid-catechol interactions. A spectroscopic assay was developed to study the polymerization of L-dopa to synthetic melanin in the presence of para-substituted aryl boronic acids. The best inhibition was observed for aryl boronic acids with electron-withdrawing substituents. The IC50 values exhibit a correlation with the Hammett sigma(p) parameter (rho = 0.97, r(2) = 0.92).

Spectroelectrochemical Studies Of Metalloporphyrins In Room Temperature Ionic Liquid, Yong Soo Hoo

Master's Theses (2009 -)

The oxidation/reduction reactions of porphyrins and metalloporphyrins play an important role in medicinal, industrial and biochemical reactions. Metalloporphyrins are particularly useful as potential catalysts for a variety of processes including catalytic oxidations. The unique properties of metalloporphyrins make them good candidates as electrocatalysts for fuel cells. Metalloporphyrins also play some important roles in biological functions.

By incorporating spectroscopic experiments such as UV-visible or infra-red spectroscopy along with electrochemical experiments such as cyclic voltammetry, one is able to determine the structural changes of the molecule when oxidation or reduction reaction is carried out.

Chemical Modification And Biological Activity Exploration Of The Natural Product-Gossypol, Juanjuan Yin

All Dissertations

Gossypol is a naturally occurring, highly colored yellow pigment indigenous to the small intercellular pigment glands of the cotton plant genus Gossypium, which is proposed to be part of plant's defense system. Gossypol is characterized by wide contraceptive, antiviral, anticancer and antifungal properties. However, the relatively high toxicity of gossypol precludes its application in medical therapy. For this reason the syntheses and tests of gossypol derivatives, have been tried to enable their application as drugs. In our study, gossypol based methylation, glycosylation and nanoconjugate reactions were explored. The gossypol derivatives were all fully characterized by NMR, MS, FT-IR, UV spectrometry, …

Synthesis And Characterization Of Monolayer Protected Gold Nanoparticles And A Gold-Titanium Dioxide Nanocomposite Intended For Photocatalytic Degradation Of Environmental Pollutants, Piyadarsha Amaratunga

Dissertations

Semiconductor and metal clusters in the nanometer size regime display interesting optical, electronic and chemical properties that are size dependant. Highly monodisperse gold nanoparticles of different sizes have been synthesized and isolated by newly developed methodologies, using tiopronin as the capping ligand. Titanium dioxide nanoparticles (Ti0₂) have been used as the photocatalytic center and gold nanoparticles have been attached on Ti0₂ to make a nanocomposite. According to the findings, gold nanoparticles play a vital role in enhancing the photocatalytic activity of Ti0₂, by facilitating the charge separation. Further, the photocatalytic activity also can be tuned …

Peroxisomal Plant 3-Ketoacyl-Coa Thiolase Structure And Activity Are Regulated By A Sensitive Redox Switch, Valerie E. Pye, Caspar E. Christensen, Jim Dyer, Susan Arent, Anette Henriksen

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

The breakdown of fatty acids, performed by the β-oxidation cycle, is crucial for plant germination and sustainability. β-Oxidation involves four enzymatic reactions. The final step, in which a two-carbon unit is cleaved from the fatty acid, is performed by a 3-ketoacyl-CoA thiolase (KAT). The shortened fatty acid may then pass through the cycle again (until reaching acetoacetyl-CoA) or be directed to a different cellular function. Crystal structures of KAT from Arabidopsis thaliana and Helianthus annuus have been solved to 1.5 and 1.8 Å resolution, respectively. Their dimeric structures are very similar and exhibit a typical thiolase-like fold; dimer formation and …

Ribosomal Synthesis Of N-Methylated Peptides, Sara Ahadi

Theses and Dissertations

Natural peptide products isolated from various organisms often contain N-methylated backbones. Such a modification of backbone of the peptide changes its conformational rigidity. This modification improves the biological properties of the peptide, such as improved target affinity, proteolytic stability or membrane permeability. Therefore synthesis of N-methylated peptide libraries is valuable in screening for drug-like peptides suitable for therapeutic uses. Protein synthesis using recombinant elements (PURE) and Flexizyme were used in order to reassign specific codons to N-methyl amino acids. mRNA-dependent translation system enable us to make our desired peptides with N-methyl amino acids. This technology is a convenient tool for …