Physical Sciences and Mathematics Commons^™

Fluorescence Of Supported Phospholipid Bilayers Recorded In A Conventional Horizontal-Beam Spectrofluorometer, Elizaveta A. Kovrigina, Evgeni L. Kovrigin

Chemistry Faculty Research and Publications

Supported phospholipid bilayers are a convenient model of cellular membranes in studies of membrane biophysics and protein-lipid interactions. Traditionally, supported lipid bilayers are formed on a flat surface of a glass slide to be observed through fluorescence microscopes. This paper describes a method to enable fluorescence detection from the supported lipid bilayers using standard horizontal-beam spectrofluorometers instead of the microscopes. In the proposed approach, the supported lipid bilayers are formed on the inner optical surfaces of the standard fluorescence microcell. To enable observation of the bilayer absorbed on the cell wall, the microcell is placed in a standard fluorometer cell …

Studies On Hydroxyl Radical Formation And Correlated Photoflocculation Process Using Degraded Wood Leachate As A Cdom Source, Luni Sun, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

In this study, we examined hydroxyl radical (•OH) formation with respect to photoreactivity of colored dissolved organic matter (CDOM), the Fenton reaction, and photoflocculation using leachate from decaying wood. The relationship between •OH photoproduction rate and leachate optical properties (UV-visible absorption and fluorescence excitation-emission matrices (EEMS)) was studied during irradiation using a UV solar simulator. The results showed that the •OH photochemical formation rate is strongly related to humic-like fluorescence as characterized by parallel factor analysis (PARAFAC), and that these fluorescence components are more photolabile than most of the other CDOM components. Fourier transform infrared spectroscopy (FT-IR) indicated the photodegradation …

The Nicotine Metabolite, Cotinine, Alters The Assembly And Trafficking Of A Subset Of Nicotinic Acetylcholine Receptors, Ashley M. Fox, Faruk H. Moonschi, Christopher I. Richards

Chemistry Faculty Publications

Exposure to nicotine alters the trafficking and assembly of nicotinic receptors (nAChRs), leading to their up-regulation on the plasma membrane. Although the mechanism is not fully understood, nicotine-induced up-regulation is believed to contribute to nicotine addiction. The effect of cotinine, the primary metabolite of nicotine, on nAChR trafficking and assembly has not been extensively investigated. We utilize a pH-sensitive variant of GFP, super ecliptic pHluorin, to differentiate between intracellular nAChRs and those expressed on the plasma membrane to quantify changes resulting from cotinine and nicotine exposure. Similar to nicotine, exposure to cotinine increases the number of α4β2 receptors on the …

A Structurally-Tunable 3-Hydroxyflavone Motif For Visible Light-Induced Carbon Monoxide-Releasing Molecules (Corms), Stacey N. Anderson, Jason M. Richards, Hector J. Esquer, Abby D. Benninghoff, Atta M. Arif, Lisa M. Berreau

Chemistry and Biochemistry Faculty Publications

Molecules that can be used to deliver a controlled amount of carbon monoxide (CO) have the potential to facilitate investigations into the roles of this gaseous molecule in biology and advance therapeutic treatments. This has led to the development of light-induced CO-releasing molecules (photoCORMs). A goal in this field of research is the development of molecules that exhibit a combination of controlled CO release, favorable biological properties (e.g., low toxicity and trackability in cells), and structural tunability to affect CO release. Herein, we report a new biologically-inspired organic photoCORM motif that exhibits several features that are desirable in a next-generation …

Synthetic Approaches To Flexible Fluorescent Conjugated Polymers, Tereza Vokata

FIU Electronic Theses and Dissertations

Conjugated polymers (CPs) are intrinsically fluorescent materials that have been used for various biological applications including imaging, sensing, and delivery of biologically active substances. The synthetic control over flexibility and biodegradability of these materials aids the understanding of the structure-function relationships among the photophysical properties, the self-assembly behaviors of the corresponding conjugated polymer nanoparticles (CPNs), and the cellular behaviors of CPNs, such as toxicity, cellular uptake mechanisms, and sub-cellular localization patterns.

Synthetic approaches towards two classes of flexible CPs with well-preserved fluorescent properties are described. The synthesis of flexible poly(p-phenylenebutadiynylene)s (PPBs) uses competing Sonogashira and Glaser coupling reactions …

Sequence-Specific, Nanomolar Peptide Binding Via Cucurbit[8]Uril-Induced Folding And Inclusion Of Neighboring Side Chains, Lauren C. Smith, David G. Leach, Brittney E. Blaylock, Omar A. Ali, Adam R. Urbach

Chemistry Faculty Research

This paper describes the molecular recognition of the tripeptide Tyr-Leu-Ala by the synthetic receptor cucurbit[8]uril (Q8) in aqueous buffer with nanomolar affinity and exceptional specificity. This combination of characteristics, which also applies to antibodies, is desirable for applications in biochemistry and biotechnology but has eluded supramolecular chemists for decades. Building on prior knowledge that Q8 binds to peptides with N-terminal aromatic residues, a library screen of 105 peptides was designed to test the effects of residues adjacent to N-terminal Trp, Phe, or Tyr. The screen used tetramethylbenzobis(imidazolium) (MBBI) as a fluorescent indicator and resulted in the unexpected discovery that MBBI …

Grazing Incidence X-Ray Fluorescence Measurements Of Genesis Sample 30580 For Determination Of Manganese And Nickel Fluences, Martina Schmeling, J. Davidson, P.J. Eng, J.E. Stubbs, A.J.G. Jurewicz, D.S. Burnett

Chemistry: Faculty Publications and Other Works

Genesis flight sample 30580 was analyzed by grazing incidence X-ray fluorescence spectrometry for subsequent calculation of Mn and Ni fluences.

Wavelength Dependent Specific Plasmon Resonance Coupling Of Single Silver Nanoparticles With Egfp, Kerry J. Lee, Tao Huang, Prakash D. Nallathamby

Chemistry & Biochemistry Faculty Publications

Noble metal nanoparticles (NPs) possess unique plasmonic properties, enabling them to serve as sub-diffraction light sources and nano-antennae for a wide range of applications. Here we report the specific interaction of single Ag NPs with single EGFP molecules and a high dependence of their interaction upon localized-surface-plasmon-resonance (LSPR) spectra of single Ag NPs and EGFP. The LSPR spectra of single red Ag NPs show a stunning 60 nm blue-shift during their incubation with EGFP, whereas they remain unchanged during their incubation with bovine serum albumin (BSA). Interestingly, the peak wavelengths of the LSPR spectra of green and blue Ag NPs …

Characterization And Photodegradation Of Dissolved Organic Matter (Dom) From A Tropical Lake And Its Dominant Primary Producer, The Cyanobacteria Microcystis Aeruginosa, Thais B. Bittar, Aron Stubbins, Armando A. H. Vieira, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

This study investigates optical and high-resolution molecular signatures and photochemical degradation of DOM from the Barra Bonita Reservoir (BB-DOM), a tropical eutrophic lake, as well as from its dominant phytoplankton species, the cyanobacteria Microcystis aeruginosa (Microcystis-DOM). Consistent with a predominantly autotrophic source, BB-DOM and Microcystis-DOM exhibited high protein-like fluorescence and contained a large number of aliphatics. Microcystis-DOM was enriched in peptide-like formulae, while BB-DOM had higher chromophoric and fluorescent DOM(CDOM and FDOM) and was enriched in moderately unsaturated formulae, indicating additions of terrigenous DOM and/or in situ processing of autochthonous material in the lake. Consistent with …

Fluorescence Monitoring And Parallel Factor Analysis Of Contaminant Mixtures In Water, Nina M. Caputo

Honors College

Pharmaceuticals and Personal Care Products (PPCPs) pollute our water systems regularly by entering the environment through inefficient methods of water treatment, ineffective sanitation and unregulated industrial and agricultural runoff. Currently, the most common methods of identifying PCPPs are expensive, time consuming and often require the aid of a trained expert. This project aims to further the methodology of utilizing fluorescence spectroscopy as a means of pollutant detection with a focus on contaminant mixtures. Four non-regulated EPA contaminants were fluoresced at compound specific EEM parameters and then again in two component mixtures to determine their limits of detection (LOD). The results …

Optical Characterization And Distribution Of Chromophoric Dissolved Organic Matter (Cdom) In Soil Porewater From A Salt Marsh Ecosystem, Catherine D. Clark, Paige Aiona, Jason K. Keller, Warren J. De Bruyn

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

To characterize chromophoric dissolved organic matter (CDOM) in marsh porewaters and its contribution as a carbon source, optical properties (absorbance, fluorescence indices, 3-dimensional excitation-emission matrices [EEMs]) of soil porewater and surface water were measured in a southern Californian salt marsh. Absorption coefficients and fluorescence intensities were higher in porewater than in overlying surface waters, consistent with higher CDOM concentration at depth. Humic-type peaks A and C were observed in EEMs in all samples, and peak M was observed in surface waters and shallow porewater to -5 cm depth. Fluorescence:absorbance (flu:abs) ratios and spectral slopes (S) decreased across the surface interface, …

Analysis Of Genesis Sample 60234 By Laboratory Total Reflection X-Ray Fluorescence Spectrometry And Synchrotron Grazing Incidence X-Ray Fluorescence, Martina Schmeling, E. Hwang, Y. Choi, P.J. Eng, J.E. Stubbs, I.V. Veryovkin

Chemistry: Faculty Publications and Other Works

Genesis sample 60234 was characterized by laboratory TXRF and synchrotron GI-XRF. Surface contaminants were identified as well as elements within the bulk.

On Readout Of Vibrational Qubits Using Quantum Beats, Dmytro Shyshlov, Eduardo Berrios, Martin Gruebele, Dmitri Babikov

Chemistry Faculty Research and Publications

Readout of the final states of qubits is a crucial step towards implementing quantum computation in experiment. Although not scalable to large numbers of qubits per molecule, computational studies show that molecular vibrations could provide a significant (factor 2–5 in the literature) increase in the number of qubits compared to two-level systems. In this theoretical work, we explore the process of readout from vibrational qubits in thiophosgene molecule, SCCl₂, using quantum beat oscillations. The quantum beats are measured by first exciting the superposition of the qubit-encoding vibrational states to the electronically excited readout state with variable time-delay pulses. …

Molecular Level Interaction Of Human Fibroblast Growth Factor-1 (Hfgf-1) With Phloridzin, Rammohan Paripelly

Masters Theses & Specialist Projects

Fibroblast growth factors (FGFs) are a family of growth factors which includes twenty three proteins. FGFs work as modulators for various cellular activities like mitosis, differentiation and survival. Among the FGF family, human fibroblast growth factor-1 (hFGF-1), which is also known as acidic fibroblast growth factor, is a potent angiogenic agent, involved in the formation of new blood vessels in various tissues. hFGF-1 is regarded as a prototype of the FGF family. It serves as one of the potential targets in tumor inhibition and obesity due to its involvement in new blood vessel formation in cancerous regions and adipose tissues. …

Bcl-2 Promoter Sequence G-Quadruplex Interactions With Three Planar And Non-Planar Cationic Porphyrins: Tmpyp4, Tmpyp3, And Tmpyp2., Vu H. Le, Narayana Nagesh, Edwin A. Lewis

College of Arts and Sciences Publications and Scholarship

The interactions of three related cationic porphyrins, TMPyP4, TMPyP3 and TMPyP2, with a WT 39-mer Bcl-2 promoter sequence G-quadruplex were studied using Circular Dichroism, ESI mass spectrometry, Isothermal Titration Calorimetry, and Fluorescence spectroscopy. The planar cationic porphyrin TMPyP4 (5, 10, 15, 20-meso-tetra (N-methyl-4-pyridyl) porphine) is shown to bind to a WT Bcl-2 G-quadruplex via two different binding modes, an end binding mode and a weaker mode attributed to intercalation. The related non-planar ligands, TMPyP3 and TMPyP2, are shown to bind to the Bcl-2 G-quadruplex by a single mode. ESI mass spectrometry experiments confirmed that the saturation stoichiometry is 4:1 for …

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 …

Interaction Of Extracellular Domain 2 Of The Human Retina-Specific Atp-Binding Cassette Transporter (Abca4) With All-Trans-Retinal., Esther E Biswas-Fiss, Deepa S Kurpad, Kinjalben Joshi, Subhasis B Biswas

Department of Medical Laboratory Sciences & Biotechnology Faculty Papers

The retina-specific ATP-binding cassette (ABC) transporter, ABCA4, is essential for transport of all-trans-retinal from the rod outer segment discs in the retina and is associated with a broad range of inherited retinal diseases, including Stargardt disease, autosomal recessive cone rod dystrophy, and fundus flavimaculatus. A unique feature of the ABCA subfamily of ABC transporters is the presence of highly conserved, long extracellular loops or domains (ECDs) with unknown function. The high degree of sequence conservation and mapped disease-associated mutations in these domains suggests an important physiological significance. Conformational analysis using CD spectroscopy of purified, recombinant ECD2 protein demonstrated that it …

Ultrafast Optical Study Of Small Gold Monolayer Protected Clusters: A Closer Look At Emission, S. Hei Yau, O. Varnavski, John D. Gilbertson, Bert D. Chandler, G. Ramakrishna, T. Goodson

Chemistry Faculty Research

Monolayer-protected metal nanoclusters (MPCs) were investigated to probe their fundamental excitation and emission properties. In particular, gold MPCs were probed by steady-state and time-resolved spectroscopic measurements; the results were used to examine the mechanism of emission in relation to the excited states in these systems. In steady-state measurements, the photoluminescence of gold clusters in the range of 25 to 140 atoms was considerably stronger relative to larger particle analogues. The increase in emission efficiency (for Au₂₅, Au₅₅, and Au₁₄₀ on the order of 10^-5) over bulk gold may arise from a different mechanism …

Construction, Figures Of Merit And Testing Of A Single-Cell Fluorescence Excitation Spectroscopy System, Laura S. Hill, Tammi L. Richardson, Louisa T.M. Profeta, Timothy J. Shaw, Christopher J. Hintz, Benjamin S. Twining, Evelyn Lawrenz, Micheal L. Myrick

Faculty Publications

Characterization of phytoplankton community composition is critical to understanding the ecology and biogeochemistry of the oceans. One approach to taxonomic characterization takes advantage of differing pigmentation between algal taxa and thus differences in fluorescence excitation spectra. Analyses of bulk water samples, however, may be confounded by interference from chromophoric dissolved organic matter or suspended particulate matter. Here, we describe an instrument that uses a laser trap based on a Nikon TE2000-U microscope to position individual phytoplankton cells for confocal fluorescence excitation spectroscopy, thus avoiding interference from the surrounding medium. Quantitative measurements of optical power give data in the form of …

Mutational Studies Uncover Non-Native Structure In The Dimeric Kinetic Intermediate Of The H2a–H2b Heterodimer, Matthew R. Stump, Lisa M. Gloss

Faculty Publications - Department of Biological & Molecular Science

The folding pathway of the histone H2A–H2B heterodimer minimally includes an on-pathway, dimeric, burst-phase intermediate, I2. The partially folded H2A and H2B monomers populated at equilibrium were characterized as potential monomeric kinetic intermediates. Folding kinetics were compared for initiation from isolated, folded monomers and the heterodimer unfolded in 4 M urea. The observed rates were virtually identical above 0.4Murea, exhibiting a log-linear relationship on the final denaturant concentration. Below ∼0.4 M urea (concentrations inaccessible from the 4-M urea unfolded state), a rollover in the rates was observed; this suggests that a component of the I2 ensemble contains non-native structure that …

Patterning High Surface Area Silica With Lysozyme: Adsorption Kinetics, Fluorescence Quenching, And Protein Readsorption Studies To Evaluate The Templated Surface, Rachel M. Greer, Brittni A. Scruggs, R Alan May, Bert D. Chandler

Chemistry Faculty Research

A method was developed for using an inexpensive and widely available protein, hen egg white lysozyme, as a patterning agent for commercial high surface area silicas. The basic patterning methodology involved spontaneous adsorption of the protein from aqueous solution, alkylation of the uncovered surface with an alkylsiloxane, and protein desorption in a slightly alkaline solution of morpholine. Adsorption kinetic studies using Bradford assays assisted in determining protein deposition conditions. These studies were generally consistent with results on more planar silica surfaces and indicated that the protein quickly and strongly adsorbs along its long axis at low surface coverages. A modified …

Fluorescence Characteristics Of Triazine-Manufacturing Wastewater, Lin Huang, Shuyan Qiu, Neissa Pinzon, Li-Ta Lien, Lu-Kwang Ju

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

Samples taken at different points in the wastewater treatment process of a triazine-manufacturing plant were scanned by fluorescence spectroscopy, in the wavelength range of 200-900 nm. Reproducibly, the fluorescence spectra revealed one single major peak at excitation and emission wavelengths of 258 and 370 nm respectively. Aqueous solutions of purified active compounds, including Atrazine, Propazine, Simazine, Terbuthylazine, Metolachlor, and Benoxacor, were also scanned. No significant fluorescence was observed in these standard solutions at concentrations up to 100 mg/L. Selected plant samples as well as standard solutions of Atrazine, Metolachlor, and toluene were further analyzed using high-performance liquid chromatography with absorbance …

Determination Of Enantiomeric Compositions Of Analytes Using Novel Fluorescent Chiral Molecular Micelles And Steady State Fluorescence Measurements, Alicia A. Williams, Sayo O. Fakayode, Onur Alptürk, Christina M. Jones, Mark Lowry, Robert M. Strongin, Isiah M. Warner

Chemistry Faculty Publications and Presentations

Novel fluorescent chiral molecular micelles (FCMMs) were synthesized, characterized, and employed as chiral selectors for enantiomeric recognition of non-fluorescent chiral molecules using steady state fluorescence spectroscopy. The sensitivity of the fluorescence technique allowed for investigation of low concentrations of chiral selector (3.0 x 10(-5) M) and analyte (5.0 x 10(-6) M) to be used in these studies. The chiral interactions of glucose, tartaric acid, and serine in the presence of FCMMs poly(sodium N-undecanoyl-L-tryptophanate) [poly-L-SUW], poly(sodium N-undecanoyl-L-tyrosinate) [poly-L-SUY], and poly(sodium N-undecanoyl-L-phenylalininate) [poly-SUF] were based on diastereomeric complex formation. Poly-L-SUW had a significant fluorescence emission spectral difference as compared to poly-L-SUY and …

Mutational Analysis Of The Stability Of The H2a And H2b Histone Monomers, Matthew R. Stump, Lisa M. Gloss

Faculty Publications - Department of Biological & Molecular Science

The eukaryotic histone heterodimer H2A–H2B folds through an obligatory dimeric intermediate that forms in a nearly diffusion-limited association reaction in the stopped-flow dead time. It is unclear whether there is partial folding of the isolated monomers before association. To address the possible contributions of structure in the monomers to the rapid association, we characterized H2A and H2B monomers in the absence of their heterodimeric partner. By far-UV circular dichroism, the H2A and H2B monomers are 15% and 31% helical, respectively—significantly less than observed in X-ray crystal structures. Acrylamide quenching of the intrinsic Tyr fluorescence was indicative of tertiary structure. The …

Charge-Mediated Recognition Of N-Terminal Tryptophan In Aqueous Solution By A Synthetic Host, Meghan E. Bush, Nicole D. Bouley, Adam R. Urbach

Chemistry Faculty Research

The molecular recognition of peptides and proteins in aqueous solution by designed molecules remains an elusive goal with broad implications for basic biochemical research and for sensors and separations technologies. This paper describes the recognition of N-terminal tryptophan in aqueous solution by the synthetic host cucurbit[8]uril (Q8). Q8 is known to form 1:1:1 heteroternary complexes with methyl viologen (MV) and a second aromatic guest. Here, the complexes of Q8·MV with (i) the four natural aromatic α-amino acids, (ii) four singly charged tryptophan derivatives, and (iii) four tryptophan-containing tripeptides were characterized by isothermal titration calorimetry, mass spectrometry, and UV−visible, fluorescence, and …

The Association Of Nadph With The Guanine Nucleotide Exchange Factor From Rabbit Reticulocytes: A Role Of Pyridine Dinucleotides In Eukaryotic Polypeptide Chain Initiation, Jaydev N. Dholakia, Timothy C. Muesser, Charles L. Woodley, Lawrence J. Parkhurst, Albert J. Wahba

Chemistry Department: Faculty Publications

The guanine nucleotide exchange factor (GEF) was purified to apparent homogeneity from postribosomal supernatants of rabbit reticulocytes by chromatography on DEAE-celiulose and phosphocellulose, fractionation by glycerol gradients, and chromatography on Mono S and Mono Q (Pharmacia). At the Mono S step GEF is isolated as a complex with the eukaryotic polypeptide chain initiation factor 2 (eIF-2) and is separated from this factor by column chromatography on Mono Q. An emission spectrum characteristic of a reduced pyridine dinucleotide was observed when GEF was subjected to fluorescence analysis. By both coupled enzymatic analysis and chromatography on reverse-phase or Mono Q columns, the …

Pressure Dependence Of Fluorescent And Photolytic Interferences In Ho Detection By Laser-Excited Fluorescence, Thomas M. Hard, Robert J. O'Brien, T. B. Cook

Chemistry Faculty Publications and Presentations

In the measurement of HO concentrations by laser-excited fluorescence, expansion of the sampled air offers a way to reduce fluorescent and photolytic interference by other species. The decrease in [HO] upon expansion is balanced by an increase in HO fluorescence yield over a wide range of pressures. Background air fluorescence is reduced if the responsible species have fluorescence yields higher than those of HO. Preliminary experiments indicate that most of the fluorescence observed in laboratory air is due to such species. Upon expansion, the suppression of fluorescent interference can be no greater than the reduction in pressure, whereas the suppression …

The Kinetics Of Solvent Reorientation In Hydroxylated Solvents From The Exciting-Wavelength Dependence Of Chromophore Emission Spectra, John Milton, Robert M. Purkey, William C. Galley

WM Keck Science Faculty Papers

The disappearance of the exciting-wavelength dependence of the phosphorescence spectra of polar, aromatic chromophores in supercooled glycol–water mixtures is utilized to monitor the kinetics of solvent reorientation. Reorientation times in the nanosecond to second range are obtained for (3:2 v/v) glycerol–water and (1:1 v/v) ethylene glycol–water at 140–240 °K. The results suggest that the process is one involving a cluster of solvent molecules and in which the chromophore plays a relatively passive role. Steady-state data and direct measurements of phosphorescence shifts as a function of time indicate that the solvent reorientation process is nonexponential in nature. The decay function derived …

Petroleum Hydrocarbons From Effluents: Detection In Marine Environment, John T. Tanacredi Ph.D.

Faculty Works: CERCOM

The marine environment has become the primary disposa ground for an increasing quantity of petroleum wastes. Mushrooming demands for petroleum products and the lack of economic incentive to recycle waste oil will increase the concentrations of detrimental petroleum hydrocarbons in the marine environment

Although a continuous, low-level discharge of waste petroleum hydrocarbons into the marine environment may not be as dramatic as a major oil spill, the consequences could be more devastating over an extended period. As noted by Blumer, earlier interpretations of the environmental effects of oil must not be reevaluated in the light of recent evidence of its …