Biochemistry Commons^™

Comparison Between Tetrel Bonded Complexes Stabilized By Σ And Π Hole Interactions, Wiktor Zierkiewicz, Mariusz Michalczyk, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The σ-hole tetrel bonds formed by a tetravalent molecule are compared with those involving a π-hole above the tetrel atom in a trivalent bonding situation. The former are modeled by TH4, TH3F, and TH2F2 (T = Si, Ge, Sn) and the latter by TH2=CH2, THF=CH2, and TF2=CH2, all paired with NH3 as Lewis base. The latter π-bonded complexes are considerably more strongly bound, despite the near equivalence of the σ and π-hole intensities. The larger binding energies of the π-dimers are attributed to greater electrostatic attraction and orbital interaction. Each progressive replacement of H by F increases the strength of …

Synthesis Of Candidate Natural Killer T Cell Ligands, Teron Haynie, Shenglou Deng, Paul B. Savage

Undergraduate Honors Theses

Natural Killer T (NKT) cells are a subset of T cells that express an invariant T cell receptor (TCR) that recognizes lipid antigens in context of the CD1d molecule. CD1d presents both exogenous and endogenous glycolipids on the surface of antigen presenting cells (APCs). Multiple exogenous lipids capable of NKT cell stimulation have been characterized, but confirmed endogenous ligands are relatively few in number. Recently, a-galactosylceramides were shown to be endogenous NKT cell ligands. We have observed that a-galactosylceramides cyclize in acidic conditions. Since the biosynthetic pathway of lipid presentation via CD1d likely passes through the acidic lysosome, we propose …

Codon Usage Revisited: Lack Of Correlation Between Codon Usage And The Number Of Trna Genes In Enterobacteria, Joaquín Rojas, Gabriel Castillo, Lorenzo Eugenio Leiva, Sara Elgamal, Omar Orellana, Michael Ibba, Assaf Katz

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

It is widely believed that if a high number of genes are found for any tRNA in a rapidly replicating bacteria, then the cytoplasmic levels of that tRNA will be high and an open reading frame containing a higher frequency of the complementary codon will be translated faster. This idea is based on correlations between the number of tRNA genes, tRNA concentration and the frequency of codon usage observed in a limited number of strains as well as from the fact that artificially changing the number of tRNA genes alters translation efficiency and consequently the amount of properly folded protein …

Transcriptional Correlates Of Proximal-Distal Identify And Regeneration Timing In Axolotl Limbs, S. Randal Voss, David Murrugarra, Tyler B. Jensen, James R Monaghan

Neuroscience Faculty Publications

Cells within salamander limbs retain memories that inform the correct replacement of amputated tissues at different positions along the length of the arm, with proximal and distal amputations completing regeneration at similar times. We investigated the possibility that positional memory is associated with variation in transcript abundances along the proximal-distal limb axis. Transcripts were deeply sampled from Ambystoma mexicanum limbs at the time they were administered fore arm vs upper arm amputations, and at 19 post-amputation time points. After amputation and prior to regenerative outgrowth, genes typically expressed by differentiated muscle cells declined more rapidly in upper arms while cell …

Investigating The Role Of Gold Nanoparticle Shape And Size In Their Toxicities To Fungi, Kangze Liu, Zhonglei He, Hugh Byrne, James Curtin, Furong Tian Technological University Dublin

Articles

Gold nanoparticles (GNPs) are increasingly being used in a wide range of applications, and such they are being released in greater quantities into the environment. Consequently, the environmental effects of GNPs, especially toxicities to living organisms, have drawn great attention. However, their toxicological characteristics still remain unclear. Fungi, as the decomposers of the ecosystem, interact directly with the environment and critically control the overall health of the biosphere. Thus, their sensitivity to GNP toxicity is particularly important. The aim of this study was to evaluate the role of GNP shape and size in their toxicities to fungi, which could help …

Facially Amphiphilic Polyionene Biocidal Polymers Derived From Lithocholic Acid, Mitra S. Ganewatta, Md Anisur Rahman, Louis Mercado, Tinom Shokfai, Alan W. Decho, Theresa M. Reineke, Chuanbing Tang

Faculty Publications

Bacterial infections have become a global issue that requires urgent attention, particularly regarding to emergence of multidrug resistant bacteria. We developed quaternary amine-containing antimicrobial poly(bile acid)s that contain a hydrophobic core of lithocholic acid in the main-chain. Interestingly, by choosing appropriate monomers, these cationic polymers can form core-shell micelles. These polymers exhibited biocidal activity against both Gram-positive and Gram-negative bacterial species. It is demonstrated that the micelles can deliver hydrophobic antibiotics that functionally have dual antimicrobial activities. Cytotoxicity assays against HeLa cells showed dosage-dependent toxicity for polymers with longer linkers.

Pain And Stress In The Premature Infant, John Bryle Chong Tan

Loma Linda University Electronic Theses, Dissertations & Projects

Procedural pain and stress in premature neonates is currently assessed utilizing tools that lack objectivity and accuracy. This results in untreated or mismanaged pain. My dissertation utilized physiological methods and biochemical markers that identified pain in premature neonates and its effect on energy metabolism. The painful procedure that I examined is the retinopathy of premature (ROP) examination, a necessary and routine eye examination in the neonatal intensive care unit (NICU) that detects and identifies infants at risk for blindness due to retinal detachment. The effects of the ROP exam on peripheral and deep tissue oxyhemoglobin saturation and urinary purine degradation …

Multicomponent Analysis Using A Confocal Raman Microscope, Zhengyuan Tang, Sinead J. Barton, Thomas E. Ward, John P. Lowry, Michelle M. Doran, Hugh Byrne, Bryan M. Hennelly

Articles

Measuring the concentration of multiple chemical components in a low volume aqueous mixture by Raman spectroscopy has received significant interest in the literature. All of the contributions to date focus on the design of optical systems that facilitate the recording of spectra with high signal-to-noise ratio, by collecting as many Raman scattered photons as possible. In this study, the confocal Raman microscope set-up is investigated for multicomponent analysis. Partial Least Squares Regression is used to quantify physiologically relevant aqueous mixtures of glucose, lactic acid, and urea. The predicted error is 17.81 mg/dL for glucose, 10.6 mg/dL for lactic acid and …

An Introductory Study Of Solid Materials For Capture And Catalysis Of Waste Stream Chemicals, Steven Kyle Butler

Theses and Dissertations

Heterogeneous catalysts are key materials in research and industry. Herein we study two materials in different stages of development toward being applied as heterogeneous catalysts. First, MoO3SnO2 was synthesized and studied as a catalytic system similar to Sn-beta zeolites. While the Mo-based catalyst did not show similar activity to Sn-beta, it did show interesting reactivity in activating carbonyls and oxidizing organic substrates. Second, a method was developed for grafting amines onto carboxylic acid functionalized carbon nanotubes for CO2 capture. The method was successful for grafting monomer ethylamine groups onto CNT and can be further developed to allow for polymeric amine …

Fluorescent Probes And Functionalized Nanoparticles For Bioimaging: Synthesis, Photophysical Properties And Applications, Xinglei Liu

Dissertations

The development of new organic molecular probes with excellent photophysical properties and high fluorescence quantum yields is of considerable interest to many research areas including one- and two-photon fluorescence microscopy, fluorescence-based sensing methodologies, and cancer therapy. Series of organic linear-/non-linear optical molecules including squaraine derivatives, and fluorene derivatives as well as other bioconjugates are designed and synthesized during the doctoral study for the aim of ion detection (Chapter 5), photo dynamic therapy, and deep-tissue imaging (Chapter 4). These optical probes are capable of absorbing light in the near infrared (NIR) window and thus have deeper penetration and cause less photodamage …

Design And Assessment Of Small Molecules As Free Radical Scavengers And Potential Multi-Target Therapeutic Agents Against Alzheimer’S Disease, Diabetes And Cancer, William Horton

Graduate Doctoral Dissertations

Complex diseases such as Alzheimer’s disease (AD), diabetes and cancer are difficult to manage with single target treatment approaches and unfortunately, they are wide-spread. For example, over 16 million people are expected to have AD in the US by 2050, thus new therapeutic approaches have to be developed. Multi-functional drug candidates have gained increasing popularity in treating complex diseases. The impact of oxidative stress in almost every disease progression makes them essential components in therapies for complex diseases. Endogenous systems typically maintain redox homeostasis within the cell, but in the diseased state these systems fail to alleviate oxidative stress. Supplementation …

Identification Of A Tola Protein Binding Site For Bacterial Toxins, Monica Ferrante

Honors Projects

Group A colicins are proteinaceous bacteriocins encoded by plasmids that exploit the cellular envelope protein TolA to translocate the cell wall barrier and cellular envelope of the bacterium Escherichia coli. These colicins offer protocols for studying certain protein-protein interactions involved in such membrane transport functions. Previous experimentations suggest the carboxyl-terminal domain of TolA protein contains specific amino acid binding regions required for the translocation of group A colicins into E. coli. The amino acid sequence of this domain varies between E. coli and other gram-negative bacterial species. It has been suggested that this diversity could be utilized to …

Cyclic Urethane: A Versatile Handle For Synthetic Peptide Applications, Hader E. Elashal

Seton Hall University Dissertations and Theses (ETDs)

While peptides have impeccable potential due to their biological and therapeutic abilities, they are inherently limited in clinical practice due to their instability towards proteolysis and poor bioavailability. In the past few years peptidomimetics have emerged as a powerful class of compounds that overcomes the shortcomings associated with peptides. Peptidomimetics essentially mimic a natural peptide or protein in its chemical composition, structure and its ability to perform a biologically relevant role. In addition to increased stability and bioavailability, peptidomimetics can also have increased receptor binding affinity and selectivity, thereby making these mimics lead compounds in the field of drug design …

Effect Of Bmp Treatment On Periostin Gene Expression In Pre-Osteoblastic Mc3t3-E1 Mouse Cells, Vincent Lee Khang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Periostin is a secreted, extracellular matrix (ECM) protein widely expressed within collagen-rich fibrous connective tissues of the body including the periodontal ligament (PDL), bone, skin, heart, and cornea. Periostin has been shown to serve many important regulatory functions including cell adhesion, cell motility, wound healing and of particular importance to the dental field, differentiation of osteoblasts. The deletion of periostin compromises osteoblast attachment to bone matrix and induces a reduction in mineralization and expression of bone markers, including type I collagen, osteocalcin, osteopontin and alkaline phosphatase. Periostin has also been shown to play a significant role in collagen fibrillogenesis by …

Characterization Of A Catalyst-Based Conversion Technique To Measure Total Particulate Nitrogen And Organic Carbon And Comparison To A Particle Mass Measurement Instrument, Chelsea E. Stockwell, Agnieszka Kupc, Bartlomiej Witkowski, Ranajit K. Talukdar, Yong Liu, Vanessa Selimovic, Kyle J. Zarzana, Kanako Sekimoto, Carsten Warneke, Rebecca A. Washenfelder, Robert J. Yokelson, Ann M. Middlebrook, James M. Roberts

Chemistry and Biochemistry Faculty Publications

The chemical composition of aerosol particles is a key aspect in determining their impact on the environment. For example, nitrogen-containing particles impact atmospheric chemistry, air quality, and ecological N deposition. Instruments that measure total reactive nitrogen (Nr Combining double low line all nitrogen compounds except for N2 and N2O) focus on gas-phase nitrogen and very few studies directly discuss the instrument capacity to measure the mass of Nr-containing particles. Here, we investigate the mass quantification of particle-bound nitrogen using a custom Nr system that involves total conversion to nitric oxide (NO) across platinum and molybdenum catalysts followed by NOĝ'O3 chemiluminescence …

Organic Compound Emissions From A Landfarm Used For Oil And Gas Solid Waste Disposal, Seth N. Lyman, Marc L. Mansfield

Chemistry and Biochemistry Faculty Publications

Solid or sludgy hydrocarbon waste is a byproduct of oil and gas exploration and production. One commonly-used method of disposing of this waste is landfarming. Landfarming involves spreading hydrocarbon waste on soils, tilling it into the soil, and allowing it to biodegrade. We used a dynamic flux chamber to measure fluxes of methane, a suite of 54 non-methane hydrocarbons, and light alcohols from an active and a remediated landfarm in eastern Utah, U.S.A. Fluxes from the remediated landfarm were not different from a PTFE sheet or from undisturbed soils in the region. Fluxes of methane, total non-methane hydrocarbons, and alcohols …

Synthetic Routes To Bromo-Terminated Phosphonate Films And Alkynyl Pyridine Compounds For Click Coupling, Poornima Sunder

Departmental Honors & Graduate Capstone Projects

Click reactions are a highly versatile class of reactions that produce a diverse range of products. Copper-catalyzed azide-alkyne cycloaddition (CuAAC) click reactions require an azide and a terminal alkyne and produce a coupled product that is “clicked” through a triazole ring that can have a variety of substituents. In this work, bromo-terminated phosphonate films on copper oxide surfaces were explored as the platform for click coupling, as the terminal azide needed for the reaction can be generated through an in situ SN2 reaction with a terminal bromo group. The reactions were characterized using model reactions in solution before being conducted …

An N-Terminal Acidic Domain In Β-Amylase2 Is Required For K+ Regulation., Jillian Breault

Senior Honors Projects, 2010-2019

In the chloroplasts of leaf mesophyll cells, β-amylase proteins (BAMs) are responsible for breaking down starch into maltose when the plant cannot undergo photosynthesis. BAM2, which was previously considered inactive, was recently shown to be active under stromal-like levels of salt and has optimal activity at 80mM KCl. In addition, BAM2 is active as a tetramer in vivo and displays sigmoidal kinetics due to a secondary binding site that is responsible for activating BAM2 when bound to starch. A hypothesized tetramer model was created using a homology model of a BAM2 monomer and the configuration of a crystallized sweet potato …

Molecular Mechanism Of Early Amyloid Self-Assembly Revealed By Computational Modeling, Mohtadin Hashemi

Theses & Dissertations

Protein misfolding followed by the formation of aggregates, is an early step in the cascade of conformational changes in a protein that underlie the development of several neurodegenerative diseases, including Alzheimer’s and Parkinson’s diseases. Efforts aimed at understanding this process have produced little clarity and the mechanism remains elusive.

Here, we demonstrate that the hairpin fold, a structure found in the early folding intermediates of amyloid b, induces morphological and stability changes in the aggregates of Aβ(14-23) peptide. We structurally characterized the interactions of monomer and hairpin using extended molecular dynamics (MD) simulations, which revealed a novel intercalated type complex. …

Elucidation Of The Functions Of Neuropilin 2 In Osteoclasts In Promoting Prostate Cancer Bone Metastasis., Navatha S. Polavaram

Theses & Dissertations

Bone metastasis is one of the major clinical concerns that causes skeletal related malignancies and increased mortality. Bone is one of the preferred sites for metastatic prostate cancer. The metastatic prostate cancer cells interact with bone cells (osteoblasts and osteoclasts) resulting in an imbalance in the bone homeostasis leading to increased activation of osteoblasts over osteoclasts. Our preliminary data indicated a non-tyrosine kinase receptor Neuropilin 2 (NRP2) is expressed in osteoclasts induced by metastatic prostate cancer cells and acts as a negative regulator of osteoclast differentiation and function. We hypothesize that prostate cancer -induced NRP2 expression in osteoclasts is necessary …