Digital Commons Network^™

Anaerobic Biotransformation Of Environmental Pollutants Stimulated By Electric Field: Electron-Transfer Mechanisms And Application Examples, Chun-Hua Feng, Dao-Hai Xie, Yun-Meng Pang, Tao Han, Chao-Hai Wei

Journal of Electrochemistry

The ability of some microorganisms to accept electrons from an electrode for the reduction of terminal electron acceptors in anaerobic environments has attracted growing interest on the electric field-stimulated biological reduction technology, which may open new possibility for the sustainable wastewater treatment and bioremediation in the field of environmental engineering. Here, we reviewed the extracellular electron transfer mechanism which is thought to play a key role in determining the feasibility and efficiency for the anaerobic biotransformation of environmental pollutants. Possible mechanisms that may be involved in bioelectrochemical reactors (BERs) with biocathodes include indirect electron transfer via hydrogen generated from water …

Experimental Design Methodology Applied To The Oxidation Of Quinolines In Aqueous Medium By Electro-Fenton Process, Souhaila Trabelsi Souissi, Nihal Oturan, Nizar Bellakhal, Mehmet A. Oturan

Journal of Electrochemistry

The degradation behavior of 8-hydroxyquinoleine sulfate (8-HQS), a model molecule of quinolines, was studied in an aqueous medium by electro-Fenton process using a carbon felt cathode and a platinum anode. The great oxidation ability of this process is due to a large production of hydroxyl radical (OH) by electrochemically induced Fenton’s reagent (H₂O₂, Fe²⁺). Hydroxyl radicals are very powerful oxidizing agents which react on organics up to complete mineralization. A factorial experimental design was used for determining the operating parameters on the degradation of 8-HQS in an aqueous medium. The results showed that the …

Α-Hydroxyhippuric Acid Derivatives: Ph-Dependent Aqueous Kinetics And Buffer Catalysis., Kati Feken

Theses and Dissertations

Synthesis and kinetic investigations of the aqueous breakdown of α-hydroxyhippuric acid derivatives as a function of pH were performed to acquire an understanding of the reactivity of this biologically relevant carbinolamide functionality.

Reactive Pathways In The Chlorobenzene–Ammonia Dimer Cation Radical: New Insights From Experiment And Theory, Scott A. Reid

Chemistry Faculty Research and Publications

Building upon our recent studies of noncovalent interactions in chlorobenzene and bromobenzene clusters, in this work we focus on interactions of chlorobenzene (PhCl) with a prototypical N atom donor, ammonia (NH₃). Thus, we have obtained electronic spectra of PhCl···(NH₃)_n (n = 1–3) complexes in the region of the PhCl monomer S₀ −S₁ (ππ*) transition using resonant 2-photon ionization (R2PI) methods combined with time-of-flight mass analysis. Consistent with previous studies, we find that upon ionization the PhCl···NH₃ dimer cation radical reacts primarily via Cl atom loss. A second channel, HCl loss, is …

Development Of A New Sugar Receptor, William D. Thomas, Dr. Paul B. Savage

Journal of Undergraduate Research

Oligosaccharides are enormously rich in structural information. They are often branched and can be bonded together by a variety of different linkages, unlike polypeptides which contain identical peptide bonds.1 For this reason, polysaccharides play a crucial role in cell recognition.2 Although carbohydrate recognition is known to take place, the event is not well understood.3 In order to better understand the hydrophobic interactions that enhance binding between sugar based receptors and various small hydrophobic molecules in aqueous solvents, the synthesis of a glucose based cavity was attempted (see Fig. 3). The cavity was carefully designed to maximize hydrophobic interactions with small …

Synthesis And Characterization Of Novel Amino-Retinoid A4-Spermine, Jeffrey Swallow, Dr. Heidi Vollmer-Snarr

Journal of Undergraduate Research

Age Related Macular Degeneration (AMD) is the leading cause of vision loss in developed countries. The accumulation of lipofuscin in the eye causes death of the retinal pigment epithelium (RPE) leading to blindness (1,2). The lipofuscin chemical A2E has been shown to have cytotoxic effect in RPE, yet much of lipofuscin has remained uncharacterized (3). We have shown that other compounds exist in lipofuscin through preliminary mass spectroscopy (MS) and high-pressure liquid chromatography (HPLC) data collected from lipofuscin samples. Our lab is working to first characterize these lipofuscin compounds and then we will also study their oxidative products in order …

Production Of A Novel Anti-Tumor Chemotherapy Agent, Jeffrey Stephens, Dr. Merrit Andrus

Journal of Undergraduate Research

Cancer is a condition unlike any other known to man. It is one of the leading causes of death in the United States. In 2000, over 500,000 deaths resulted from various cancers.1 This has led to an extensive search for improved ways to treat cancer, and has left a daunting challenge to develop new ways to treat this condition. The natural product Geldanamycin (GA), the most potent of the benzoquinone absamycin antibiotics, has shown to have great promise as an anti-tumor agent. The analog of Geldanamycin, 17-Allylanino-GA, is currently in clinical trials2, and the first total synthesis of GA was …

Isolation, Structure Identification And Cytotoxic Studies Of Biologically Active Compounds In Carica Papaya Of Ghana, Kurtis S. Staples, Dr. Steven G. Wood

Journal of Undergraduate Research

Carica papaya, commonly known as the papaya plant, is found in large abundance throughout the tropical regions of the planet. The fruit of the plant has been extensively studied with papain, a protease, being the center of research. Preliminary studies showed that compounds found in the leaves of the plant possessed anti-cancer properties. As alternatives for cancer treatment are constantly being sought, plant extracts have risen to the forefront in this hunt.1 An understanding of the structure and mode of activity of the compounds in this plant will further knowledge of how to develop chemotherapeutic agents.

Synthesis Of Hiv Integrase Inhibitors, Carl Jones, Dr. Matt A. Peterson

Journal of Undergraduate Research

We have made significant progress toward the synthesis of one branch of the library of compounds that we plan to synthesize. The scheme we have followed is shown below. Once synthesized, we plan to have the compounds tested by expert collaborators to see how well they bind HTLV integrase. In addition, they will be tested against many viruses and cancers, as well as HIV. Because they are nucleoside based, it is impossible to predict exactly what type of biological activity these compounds will have. They could possibly treat a variety of diseases.

Preferential Infection Of Germinal Center T Cells By X4 Tropic Hiv, Christopher M. Cherry, Dr. Gregory F. Burton

Journal of Undergraduate Research

HIV infects CD4 T cells through binding to CD4 and an appropriate co-receptor. Two co-receptors of concern in HIV biology are CXCR4 and CCR5 because of their affect on disease progression. The majority of transmittable HIV strains use CCR5 as a co-receptor. However, during the latter stages of disease the virus may shift from using CCR5 to using CXCR4 as its co-receptor. This change is referred to as a shift in tropism, and it is of major concern because it leads to rapid disease progression (3). The site and mechanism by which this shift occurs still elude scientists. Recent findings …

Use Of Cationic Steroid Antibiotics To Fight Drug Resistance In Gram-Positive And Gram-Negative Bacteria, Thomas Orsak, Dr. Paul Savage

Journal of Undergraduate Research

Drug resistance has become an increasing problem for clinical anti-bacterial needs and a major human health threat. Drug resistance emerges through structural or biochemical pathway changes that antibacterial drugs specifically target. Bacteria have the ability to rapidly mutate and gain resistance to antibacterial drugs because of their ability to reproduce rapidly. However some parts of bacterial cells need to stay consistent. The need for consistency for these parts arises from their complexity and their essential biological activities. One of these parts is the bacterial membrane.

A2e-Dna Interaction: A Possible Mechanism For Dna Damage, Sierra Evelyn Dabell, Dr. Heidi R. Vollmer-Snarr

Journal of Undergraduate Research

A2E, a common fluorophore found in the retinal pigment epithelial cells of the eye has been shown to have phototoxic properties. For this reason A2E has been implicated in the progressive etiology of Age-related Macular Degeneration (AMD). If the mechanism of cell death can be understood, a possible intervention can be produced. Moreover, the benefits of researching A2E are two-fold. An understanding of bisoxirane-DNA interactions holds the possibility of revealing information about the pathology of AMD and presents itself as a possible chemotherapy through photo-dynamic therapy.

The Role Of A2e In Amd And Chemotherapy, D. Joshua Cameron, Dr. Heidi Vollmer-Snarr

Journal of Undergraduate Research

A2E is implicated in the etiology of AMD. We have found significant concentrations of A2E present in both lipofuscin and melanolipofuscin of human retinal pigment epithelial (RPE) cells, meaning that A2E is likely more involved in AMD than originally thought. Evidence shows that A2E, in small concentrations, is not cytotoxic alone, but becomes toxic when exposed to blue light. The light mechanism involved in A2E toxicity can be controlled and used to trigger cytotoxicity in cancer cell lines. The implications of A2E in AMD and the applications of A2E’s light triggered cytotoxicity as a possible chemotherapeutic treatment were further elucidated …

An Ab-Initio Study Of Pyrrole And Imidazole Arylamides, Abramyan Ara, Zhiwei Liu, Vojislava Pophristic

College of Science & Mathematics Departmental Research

Arylamide foldamers have been shown to have a number of biological and medicinal applications. For example, a class of pyrrole-imidazole polyamide foldamers is capable of binding specific DNA sequences and preventing development of various gene disorders, most importantly cancer. Molecular dynamics (MD) simulations can provide crucial details in understanding the atomic level events related to foldamer/DNA binding. An important first step in the accurate simulation of these foldamer/DNA systems is the reparametrization of force field parameters for torsion around the aryl-amide bonds. Here we highlight our Density Functional Theory (DFT) potential energy profiles and derived force field parameters for four …

Isolation Of A 55 Kd Protein That Specifically Binds The 3′ Au-Rich Element Of Interleukin-1b Messenger Rna, David Emergy Skarda, Dr. Roger L. Kaspar

Journal of Undergraduate Research

The polypeptide Interleukin- 1(IL-1) is one of the key mediators of the body’s response to microbial invasion, inflammation, immunological reactions, and tissue injury.1 IL- 1gene expression regulation occurs at many steps. One of the steps currently being researched is translation. Recent research indicates that the translational regulation mechanisms of IL- 1include an AU-rich element in the 3′ untranslated region (Fig. 1).2 In this mechanism, an induced protein binds to the AU-rich element (ARE) causing a decrease in translation efficiency. Isolation and subsequent identification of the ARE binding protein may lead to effective new drugs that induce the ARE binding protein …

Function And Distribution Of Apolipoprotein A1 In The Artery Wall Are Markedly Distinct From Those In Plasma, Joseph A. Didonato, Ying Huang, Kulwant S. Aulak, Orli Even-Or, Gary Gerstenecker, Valentin Gogonea, Yuping Wu, Paul L. Fox, W.H. Wilson Tang, Edward F. Plow, Jonathan D. Smith, Edward A. Fisher, Stanley L. Hazen

Chemistry Faculty Publications

Background—Prior studies show that apolipoprotein A1 (apoA1) recovered from human atherosclerotic lesions is highly oxidized. Ex vivo oxidation of apoA1 or high-density lipoprotein (HDL) cross-links apoA1 and impairs lipid binding, cholesterol efflux, and lecithin-cholesterol acyltransferase activities of the lipoprotein. Remarkably, no studies to date directly quantify either the function or HDL particle distribution of apoA1 recovered from the human artery wall. Methods and Results—A monoclonal antibody (10G1.5) was developed that equally recognizes lipid-free and HDL-associated apoA1 in both native and oxidized forms. Examination of homogenates of atherosclerotic plaque–laden aorta showed >100-fold enrichment of apoA1 compared with normal aorta (P<0.001). Surprisingly, buoyant density fractionation revealed that only a minority (<3% of total) of apoA1 recovered from either lesions or normal aorta resides within an HDL-like particle (1.063≤d≤1.21). In contrast, the majority (>90%) …

A Green Chemoselective And Practical Approach Toward N-(2-Azetidinonyl) 25-Disubstituted Pyrroles, Debasish Bandyopadhyay, Elvira Rhodes, Bimal K. Banik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Pyrrole and 2-azetidinone are two essential heterocyclic scaffolds, which are being broadly used in medicinal chemistry and drug discovery field. A green and practical method to synthesize novel N-(2-azetidinonyl) 2,5-disubstituted pyrroles, which are comprised of both pyrrole and 2-azetidinone moieties, has been developed. The classical Paal–Knorr reaction is one of the simplest and most economical methods for the synthesis of biologically important and pharmacologically useful pyrrole derivatives. The present procedure for the synthesis of N-(2-azetidinonyl) 2,5-disubstituted pyrroles (1,2,5-trisubstituted pyrroles) has been accomplished by reacting 3-amino β-lactams and 2,5-hexanedione in the presence of bismuth nitrate pentahydrate as an ecofriendly …

Improving The Sweeping Efficiency Of Permanganate Into Low Permeable Zones To Treat Tce: Experimental Results And Model Development, Chanat Chokejaroenrat, Negin Kananizadeh, Chainarong Sakulthaew, Steve D. Comfort, Yusong Li

Nebraska Water Center: Faculty Publications

The residual buildup and treatment of dissolved contaminants in low permeable zones (LPZs) is a particularly challenging issue for injection-based remedial treatments. Our objective was to improve the sweeping efficiency of permanganate into LPZs to treat dissolved-phase TCE. This was accomplished by conducting transport experiments that quantified the ability of xanthan-MnO₄⁻ solutions to penetrate and cover (i.e., sweep) an LPZ that was surrounded by transmissive sands. By incorporating the non-Newtonian fluid xanthan with MnO₄⁻, penetration of MnO₄⁻ into the LPZ improved dramatically and sweeping efficiency reached 100% in fewer pore volumes. To quantify …

Raman Spectroscopy As A Teaching Tool In The Forensic Science And Chemistry Courses, Zhaohua Dai, Elmer-Rico E. Mojico

Cornerstone 3 Reports : Interdisciplinary Informatics

No abstract provided.

Synthesis Of Orthogonally Protected 1,2-Diaminopropanoic Acids By Ring-Opening Of 3-Unsubstituted N-Activated Aziridine 2-Carboxylates With Para-Methoxybenzylamine: A Study Of The Regioselectivity Of The Reaction, Fintan Kelleher, Keith O'Brien

Articles

Orthogonally protected 1,2-diaminopropanoic acids (DAPs) have been synthesised in good yields by the ring-opening of 3-unsubstituted N-activated aziridine 2-carboxylates with para-methoxybenzylamine. The choice of both the N-activating group and ester alkyl group had a significant influence on the ratio of attack at the a or b positions of the aziridine. However, the regiochemical outcome is not predictable.

Influence Of Cholesterol And Bilayer Asymmetry On Membrane Protein Distribution In Polymer-Tethered Raft-Mimicking Lipid Membranes, Noor Fueza Hussain

Open Access Dissertations

It is now widely recognized that lipid rafts, which are membrane domains enriched in cholesterol (CHOL) and sphingolipids (SL), play a significant functional role in the plasma membrane. Raft domains particularly affect membrane functionality by causing sequestering of membrane proteins. Underlying mechanisms of raft-associated membrane protein sequestration remain elusive, due to the complexity, transient nature, and small size of raft domains in cellular membranes. To address these challenges, this dissertation unveils the relationship between lipid raft composition and membrane protein sequestration and function using raft-mimicking model membrane mixtures comprised of coexisting liquid-ordered (lo) and liquid-disordered (ld) domains with reconstituted membrane …

Development Of A Field-Portable Miniature Mass Spectrometer Designed For In-Situ Analysis And Ion Trap Miniaturization, Paul Isaac Hendricks

Open Access Dissertations

Chemical analysis by mass spectrometry has become the gold standard due to the sensitivity, selectivity, and short analysis times that are afforded by the method. Advances in miniaturized vacuum systems, mass analyzers, electronics, and ionization sources have allowed for the development of field-portable mass spectrometers. The performance of portable instruments has received much attention for their utility in the detection of illicit drugs, explosives, environmental contaminants, therapeutic drugs, and more recently, biological tissues. Furthermore, detection of the aforementioned compounds can be completed at atmospheric pressures and in the presence of complex matrices and sample surfaces when used in conjunction with …

Acquisition Of An Electrochemical System Instrument For The Development Of Sensors, Elmer-Rico E. Mojico

Cornerstone 1 Reports : Expansion and Enhancements of the Thinkfinity Platform

No abstract provided.

Suspended Lipid Bilayer For Optical And Electrical Measurements Of Single Ion Channel Proteins, Suneth P. Rajapaksha, Xuefei Wang, H. Peter Lu

Chemistry Faculty Publications

Making and holding an artificial lipid bilayer horizontally in an aqueous solution within the microscopic working distance of similar to 100 mu m are essential for simultaneous single molecule imaging and single ion-channel electrical current recording. However, preparation of such a lipid bilayer without a solid support is technically challenging. In a typical supported lipid bilayer, the asymmetric local environments and the strong perturbation of the underneath solid or dense surface can diverge the normal behavior of membrane proteins and lipids. On the other hand, the suspended lipid bilayers can provide a native local environment for the membrane proteins and …

Development Of Isotags For Nmr Based Metabolite Profiling And Applications, Fariba Tayyari

Open Access Dissertations

NMR spectroscopy is a powerful analytical tool for both qualitative and quantitative metabolite profiling analysis. However, accurate quantitative analysis of biological systems especially using one dimensional NMR has been challenging due to signal overlap. In contrast, the enhanced resolution and sensitivity offered by chemoselective isotope tags have enabled new and enhanced methods for detecting hundreds of quantifiable metabolites in biofluids using NMR spectroscopy or mass spectrometry. In this thesis we show improved sensitivity and resolution of NMR experiments imparted by 15N and 13C isotope tagging which enables the accurate analysis of plasma metabolites. To date, isotope tagging has been used …

Construction And Demonstration Of A Tandem Mass Spectrometer Based Instrument For Cold Ion Spectroscopy, James Gerhardt Redwine

Open Access Dissertations

A new instrument incorporating ion trap based tandem mass spectrometry and cold ion UV and UV-IR double resonance spectroscopy has been developed at Purdue University for the study of gas phase, biologically relevant ions. The instrument incorporates multiple quadrupole linear ion trap mass analyzers to prepare and isolate the precursor ions as well as to analyze the resultant photofragments. A 22-pole ion trap cooled to 5 K via a closed cycle helium cryostat is used to cool the ions for spectroscopic interrogation. Results show the vibrational and rotational temperature of a wide assortment of ions to be 12±2 K.

The …

Utilization Of Biomass Derived Furans In Value-Added Organics And Heterogeneous Oxorhenium Catalysts For Deoxydehydration Of Diols, Benjamin L. Wegenhart

Open Access Dissertations

As fossil fuels are depleted, there is a growing focus on renewable chemicals based on biomass materials, including both fuels and chemical feedstocks. Current methods for biomass utilization include biological conversion to produce ethanol and various thermochemical routes (gasification, pyrolysis, liquefaction, hydrothermal treatment, etc.). Furfural is one particular chemical that can be obtained from lignocellulosic biomass in good yields through the dehydration of sugar residues. It can be used as a feedstock for chemicals such as furan and THF, or as a platform molecule for making liquid fuels. The objective of this research is to investigate new pathways for the …

Gas-Phase Covalent And Non-Covalent Ion/Ion Chemistry Of Biological Macromolecules, John Robert Stutzman

Open Access Dissertations

Gas-phase ion/ion chemistry involves the interaction of oppositely charged ions inside of the mass spectrometer. During this gas-phase chemistry, particle transfer (i.e., proton and electron) or synthesis can occur at rapid reaction rates. Particle transfer represents a mature area of ion/ion chemistry, while selective covalent modification represents a fairly new area of gas-phase chemistry. Gas-phase covalent chemistry is based on traditional solution phase organic chemistry.

The work demonstrated in this dissertation greatly involves gas-phase covalent and non-covalent Schiff base chemistry on peptide and protein ions. The reagent dianion, 4-formyl 1,3-benzene disulfonic acid, has been used to covalently modify unprotonated primary …

Design, Synthesis, And Evaluation Of Molecular Inhibitors For Biologically Relevant Enzymes, Sarah Emma St. John

Open Access Dissertations

The work in this thesis details the design, synthesis, and biological evaluation of molecular inhibitors for the inhibition of biologically relevant enzymes. The first three chapters of this thesis concern the polyphenol resveratrol and its inhibition of the quinone reductase 2 (QR2) enzyme. The work on this subject resulted in the complete design, synthesis, biological and structural evaluation of a second generation library of resveratrol analogues. From this work we identified a novel resveratrol analogue that inhibits QR2 in a previously unknown binding orientation. The fourth chapter of this thesis details the de novo design of molecules for the inhibition …

Synthesis Of Novel Isoprenoid Diphosphate Analogs As Chemical Tools To Investigate Protein Geranylgeranylation, Kayla Jo Temple

Open Access Dissertations

Many proteins require prenylation in order to be biologically functional. Some such proteins include the small Ras and Rho GTPase superfamilies, nuclear lamins A and B, and the kinesin motor proteins CENP-E and F. Prenyltransferase (PTase) inhibition is currently being explored as a possible treatment not only for cancer but for a wide variety of other diseases.

Clinical studies revealed that the effectiveness of farnesyltransferase inhibitors (FTIs) to treat Ras-dependent tumors is determined by which isoform of Ras is overactive. Unfortunately the majority of Ras-dependent tumors have a mutation in either the N- or K-Ras isoforms; both of these isoforms …