Physical Sciences and Mathematics Commons^™

Glyco-Modification Of Protein With O-Cyanate Chain-End Functionalized Glycopolymer Via Isourea Bond Formation, Valentinas Gruzdys, Hailong Zhang, Xue-Long Sun

Chemistry Faculty Publications

Glycoengineering aimed at addition of carbohydrates to proteins is an attractive approach to alter pharmacokinetic properties of proteins such as enhancing stability and prolonging the duration of action. We report a novel protein glyco-modification of BSA and recombinant thrombomodulin with O-cyanate chain-end functionalized glycopolymer via isourea bond formation. The protein glycoconjugates were confirmed by SDS-PAGE, western blot, and MALDI-TOF Mass Spectrometry. Protein C activation activity of the glyco-modified recombinant thrombomodulin was confirmed, proving no interference to activity from the glycopolymer modification. The isourea bond formation under mild conditions was demonstrated as an alternative method for protein modification with polymers.

Synthesis And Evaluation Of Some New Aza-B-Homocholestane Derivatives As Anticancer Agents, Yanmin Huang, Jianguo Cui, Sijing Chen, Qifu Lin, Huacan Song, Chunfang Gan, Bin Su, Aimin Zhou

Chemistry Faculty Publications

Using analogues of some marine steroidal oximes as precursors, a series of aza-B-homocholestane derivatives possessing different substituted groups at the 3-position of the steroidal nucleus were synthesized. Their biological activity against cancer cell proliferation was determined with multiple cancer cell lines. Aza-B-homocholestane derivatives possessing 3-hydroxyl, 3-hydroximino and 3-thiosemicarbazone groups displayed remarkable cytotoxicity to cancer cells via apoptosis inducing mechanism. Compounds 5, 10, 12, 15 and 18 exhibited better potency to inhibit cancer cell proliferation. In addition, compound 15 was further evaluated with three dimensional (3D) multicellular spheroids assay to determine its potency against spheroid growth. The structure-activity relationship (SAR) generated …

Metabolomic Analysis Of Liver Tissue From The Vx2 Rabbit Model Of Secondary Liver Tumors, R. Ibarra, J. E. Dazard, Y. Sandlers, F. Rehman, R. Abbas, R. Kombu, G. F. Zhang, H. Brunengraber, J. Sanabria

Chemistry Faculty Publications

Purpose. The incidence of liver neoplasms is rising in USA. The purpose of this study was to determine metabolic profiles of liver tissue during early cancer development. Methods. We used the rabbit VX2 model of liver tumors (LT) and a control group consisting of sham animals implanted with Gelfoam into their livers (LG). After two weeks from implantation, liver tissue from lobes with and without tumor was obtained from experimental animals (LT+/LT-) as well as liver tissue from controls (LG+/LG-). Peaks obtained by Gas Chromatography-Mass Spectrometry were subjected to identification. 56 metabolites were identified and their profiles compared between groups …

A Kinetic Analysis Of The Inhibition Of Fox-4 Β-Lactamase, A Plasmid-Mediated Ampc Cephalosporinase, By Monocyclic Β-Lactams And Carbapenems, Krisztina M. Papp-Wallace, Susana Mallo, Christopher R. Bethel, Magdalena A. Taracila, Andrea M. Hujer, Ana Fernandez, Julian A. Gatta, Kerri M. Smith, Yan Xu, Malcolm G.P. Page, Eric Desarbre, German Bou, Robert A. Bonomo

Chemistry Faculty Publications

Abstract: Objectives: Class C β-lactamases are prevalent among Enterobacteriaceae; however, these enzymes are resistant to inactivation by commercially available β-lactamase inhibitors. In order to find novel scaffolds to inhibit class C β-lactamases, the comparative efficacy of monocyclic β-lactam antibiotics (aztreonam and the siderophore monosulfactam BAL30072), the bridged monobactam β-lactamase inhibitor BAL29880, and carbapenems (imipenem, meropenem, doripenem and ertapenem) were tested in kinetic assays against FOX-4, a plasmid-mediated class C β-lactamase (pmAmpC). Methods: The FOX-4 β-lactamase was purified. Steady-state kinetics, electrospray ionization mass spectrometry (ESI-MS) and ultraviolet difference (UVD) spectroscopy were conducted using the β-lactam scaffolds described. Results: The Ki values …

Enhanced Lifetime Of Excitons In Nonepitaxial Au/Cds Core/Shell Nanocrystals, Scott Lambright, Evgeniia Butaeva, Natalia Razgoniaeva, Thomas Hopkins, Bryan Smith, Dimuthu Perera, Jonathan Corbin, Elena Khon, Rebekah Thomas, Pavel Moroz, Andrey Mereshchenko, Alexander N. Tarnovsky, Mikhail Zamkov

Chemistry Faculty Publications

The ability of metal nanoparticles to capture light through plasmon excitations offers an opportunity for enhancing the optical absorption of plasmon-coupled semiconductor materials via energy transfer. This process, however, requires that the semiconductor component is electrically insulated to prevent a "backward" charge flow into metal and interfacial states, which causes a premature dissociation of excitons. Here we demonstrate that such an energy exchange can be achieved on the nanoscale by using nonepitaxial Au/CdS core/shell nanocomposites. These materials are fabricated via a multistep cation exchange reaction, which decouples metal and semiconductor phases leading to fewer interfacial defects. Ultrafast transient absorption measurements …

The Mechanism Of Galvanic/Metal-Assisted Etching Of Silicon, Kurt W. Kolasinski

Chemistry Faculty Publications

No abstract provided.

Science Classics, Mark Masthay

Chemistry Faculty Publications

An essay on the impact of the works in the Imprints and Impressions: Milestones in Human Progress, an exhibition of rare books from the collection of Stuart Rose. Exhibition was held Sept. 29-Nov. 9, 2014, at the University of Dayton.

Novel Complex Mad Phasing And Rnase H Structural Insights Using Selenium Oligonucleotides, Zhen Huang, Rob Abdur, Oksana Gerlits, Jianhua Gan, Jozef Salon, Andrey Y. Kovalevsky, Alexander A. Chumanevich, Irene Weber

Chemistry Faculty Publications

No abstract provided.

Glycan Based Detection And Drug Susceptibility Of Influenza Virus, Hieu Dinh, Xiaohu Zhang, Joyce Sweeney, Yang Yang, Yun He, Abasaheb Dhawane, Suri S. Iyer

Chemistry Faculty Publications

ABSTRACT: We have developed a panel of synthetic glycans as receptor mimics for the specific capture of influenza viruses. The glycans were printed onto commercial glass slides using a free amine at the end of a spacer to generate a small focused microarray. The microarray was evaluated for its ability to capture three different strains of influenza A virus, two H1N1, A/Brisbane/59/2007 and A/Solomon Islands/3/2006 and one H3N2, A/Aichi/2/1968. We observed an excellent detection ability with some compounds exhibiting clinically relevant (101 plaque forming units) limit of detection. We also tested the drug susceptibility of current antivirals, Zanamivir and Ostelamivir …

Myoplasmic Resting Ca2+ Regulation By Ryanodine Receptors Is Under The Control Of A Novel Ca2+-Binding Region Of The Receptor, Yanyi Chen, Shenghui Xue, Juan Zou, Jose Lopez, Jenny J. Yang, Claudio Perez

Chemistry Faculty Publications

Passive SR (sarcoplasmic reticulum) Ca2+ leak through the RyR (ryanodine receptor) plays a critical role in the mechanisms that regulate [Ca2+ ]rest (intracellular resting myoplasmic free Ca2+ concentration) in muscle. This process appears to be isoform-specific as expression of either RyR1 or RyR3 confers on myotubes different [Ca2+ ]rest. Using chimaeric RyR3–RyR1 receptors expressed in dyspedic myotubes, we show that isoformdependent regulation of [Ca2+ ]rest is primarily defined by a small region of the receptor encompassing amino acids 3770– 4007 of RyR1 (amino acids 3620–3859 of RyR3) named as the CLR (Ca2+ leak regulatory) region. [Ca2+ ]rest regulation by the …

Identification Of An L-Phenylalanine Binding Site Enhancing The Cooperative Responses Of The Calcium Sensing Receptor To Calcium, Chen Zhang, Yun Huang, Yusheng Jiang, Nagaraju Mulpuri, Ling Wei, Donald Hamelberg, Edward M. Brown, Jenny J. Yang

Chemistry Faculty Publications

Functional positive cooperative activation of the extracellular calcium ([Ca2+]o)-sensing receptor (CaSR), a member of the family C G protein-coupled receptors (GPCRs), by [Ca2+]o or amino acids elicits intracellular Ca2+ ([Ca2+]i) oscillations. Here, we report the central role of predicted Ca2+-binding Site 1 within the hinge region of the extracellular domain (ECD) of CaSR and its interaction with other Ca2+-binding sites within the ECD in tuning functional positive homotropic cooperativity caused by changes in [Ca2+]o. Next, we identify an adjacent L-Phe-binding pocket that is responsible for positive heterotropic cooperativity between [Ca2+]o and L- Phe in eliciting CaSR-mediated [Ca2+]i oscillations. The hetero-communication …

Design And Synthesis Of Heterocyclic Cations For Specific Dna Recognition: From At-Rich To Mixed-Base-Pair Dna Sequences, Yun Chai, Ananya Paul, Michael Rettig, W. David Wilson, David Boykin

Chemistry Faculty Publications

The compounds synthesized in this research were designed with the goal of establishing a new paradigm for mixed-base-pair DNA sequence-specific recognition. The design scheme starts with a cell-permeable heterocyclic cation that binds to AT base pair sites in the DNA minor groove. Modifications were introduced in the original compound to include an Hbond accepting group to specifically recognize the G-NH that projects into the minor groove. Therefore, a series of heterocyclic cations substituted with an azabenzimidazole ring has been designed and synthesized for mixed-base-pair DNA recognition. The most successful compound, 12a, had an azabenzimidazole to recognize G and additional modifications …

Spectrophotometric And Spectrofluorimetric Studies On Azilsartan Medoxomil And Chlorthalidone To Be Utilized In Their Determination In Pharmaceuticals, Walid M. Ebeid, Ehab F. Elkady, Asmaa A. El-Zaher, Ramzia I. El-Bagary, Gabor Patonay

Chemistry Faculty Publications

The recently approved angiotensin II receptor blocker, azilsartan medoxomil (AZL), was determined spectrophotometrically and spectrofluorimetrically in its combination with chlorthalidone (CLT) in their combined dosage form. The UV-spectrophotometric technique depends on simultaneous measurement of the first derivative spectra for AZL and CLT at 286 and 257 nm, respectively, in methanol. The spectrofluorimetric technique depends on measurement of the fourth derivative of the synchronous spectra intensities of AZL in presence of CLT at 298 nm in methanol. The effects of different solvents on spectrophotometric and spectrofluorimetric responses were studied. For, the spectrofluorimetric study, the effect of pH and micelle-assisted fluorescence enhancement …

Design And Synthesis Of A Novel Alpha-Methylene Lactone Chemotherapeutic Agent, Mark F. Mechelke, Jason T. Brethorst, Carina Crookston, Courthney Klinkhammer, Brittany N. Miller, Curtis Payne, Makenzie Pillsbury, Christina R. Ringsmuth, Moriah Traut

Chemistry Faculty Publications

Goniothalamin, a natural product isolated from the dried stem bark of Malaysian plants of the genus Goniothalamus, has been shown to induce apoptosis in cancer cells. The bioactivity of this molecule is though to be due to its ability to react with thiols. One mechanism involves its reaction with glutathione, a natural antioxidant found in all cells. Using a four step synthetic sequence, a novel gamma-lactone analogue of goniothalamin has been prepared that replaces the endocylic double bond in goniothalamin's lactone core with an exocyclic double bond. It is anticipated that this alteration will allow the compound to react …

Bubbles: A Review Of Their Relationship To The Formation Of Thin Films And Porous Materials, Kurt W. Kolasinski

Chemistry Faculty Publications

No abstract provided.

Electronic Effects In Oxidation Reactions Utilizing Dinuclear Copper Complexes With The Bis[3-(2-Hydroxybenzylideneamino)Phenyl] Sulfone Ligand, Armando M. Guidote Jr, Ronald L. Reyes, Riyo Kashihara, Yasuhiko Kurusu, Yoshihiro Masuyama

Chemistry Faculty Publications

Copper acetate and the ligands bis[3-(3-tert-butyl-2-hydroxy-5-methoxybenzylideneamino)phenyl] sulfone and bis[3-(3,5-di-tert-butyl-2-hydroxybenzylideneamino)phenyl] sulfone were reacted to form the complexes with 2:1 copper:ligand ratio, Cu2[B(t-Bu) (OMe)BAPS](µ-OCH3)2 (4) and with 2:2 copper:ligand ratio, Cu2[B(t-Bu)2BAPS]2 (5), respectively. Structures of 4 and 5 were determined based on IR, UV-Vis, and FAB-MS data in comparison with previously characterized related copper complexes. The two complexes 4 and 5 were utilized in the oxidation of the substrates 2,4- and 2,6-di-tertbutylphenol (dtbp) at -50C with H2O2 in CH2Cl2. The coupling products are preferred in both cases. For 2,4-dtbp, yields of 4,600% and 7,200% of 3,3’,5,5’-tetra-tert-butyl-2,2’- biphenol were achieved with the use …

Novel Tuberculostatic Agents Suitable For Treatment Of Mycobacterium Tuberculosis Infections Of The Central Nervous System, Ronald Bartzatt, Preeti Sule, Suat L.G. Cirillo, Jeffrey D. Cirillo

Chemistry Faculty Publications

Aims: To demonstrate the efficacy of five small molecule compounds for inhibiting the growth of Mycobacterium tuberculosis. To present evidence that these compounds will penetrate into the central nervous system.

Study Design: Five small molecule compounds bearing a hydrazide group were synthesized utilizing microwave excitation. These compounds were then placed into tissue culture with Mycobacterium tuberculosis at various concentrations for evaluation of bacterial growth inhibition.

Place and Duration of Study: The compounds to be tested were prepared at the University of Nebraska Chemistry Department August 2013. The evaluation of antibacterial activity was determined at the Texas A&M Health Science …

Polyaniline In Situ Grafted To Graphene Sheets, Erwin P. Enriquez, Elliard Roswell S. Yanza, Geoffrey Matthew C. Tan, Christine Joy Querebilo, Armando Somintac, Arnel Salvador

Chemistry Faculty Publications

Graphene is one of the most promising allotropes of carbon with wide applications in nanotechnology. Modification of graphene by chemical means can further expand its uses. Here, liquid-exfoliated graphene is functionalized with p-aminophenyl moiety using p-nitrophenyl diazonium salts which were diazotized in situ then reduced by tin(II) chloride. The aminophenyl-graphene thus produced is further modified to form polyaniline-graphene (PANI-GNH) by in situ oxidative graft polymerization of aniline using ammonium peroxydisulfate as oxidizing agent. The properties of the PANI-GNH were compared with polyaniline/graphene blends by Raman, infrared and UV-Visible spectroscopy, and cyclic voltammetry. Indeed, PANI-GNH registered different spectrochemical and electrochemical properties …

A Loose Domain Swapping Organization Confers A Remarkable Stability To The Dimeric Structure Of The Arginine Binding Protein From Thermotoga Maritima, Alessia Ruggiero, Jonathan D. Dattelbaum, Maria Staiano, Rita Berisio, Sabato D'Auria, Luigi Vitagliano

Chemistry Faculty Publications

The arginine binding protein from Thermatoga maritima (TmArgBP), a substrate binding protein (SBP) involved in the ABC system of solute transport, presents a number of remarkable properties. These include an extraordinary stability to temperature and chemical denaturants and the tendency to form multimeric structures, an uncommon feature among SBPs involved in solute transport. Here we report a biophysical and structural characterization of the TmArgBP dimer. Our data indicate that the dimer of the protein is endowed with a remarkable stability since its full dissociation requires high temperature as well as SDS and urea at high concentrations. In order to elucidate …

Stop Rotating! One Substitution Halts The B19- Motor, Francisco Cervantes-Navarro, Gerarso Martínez-Guajardo, Edison Osorio, Diego Moreno, William Tiznado, Rafael Islas, Kelling J. Donald, Gabriel Merino

Chemistry Faculty Publications

The B₁₉^- anion and other boron species have been dubbed ‘Wankel motors’ for the almost barrierless rotation of inner and outer concentric rings relative to each other in these compounds. A single substitution in B₁₉^- is shown to shut down the well-established fluxionality in the anion. A carbon atom substituted in the structure to give a neutral CB₁₈ species is shown computationally to enforce bond localization.