Approaches Toward Novel 1,2,3-Triazole Sensors For The Detection Of Anions And Heavy Metal Cations,
2017
Georgia Southern University
Approaches Toward Novel 1,2,3-Triazole Sensors For The Detection Of Anions And Heavy Metal Cations, Richard D. Govan
College of Graduate Studies: Theses & Dissertations
Cations and anions play pivotal roles in biological and physiological processes, however an imbalance in concentration of any ion can be detrimental. Therefore, research into the selective recognition of anions and heavy metal cations has acquired much attention. One approach involves the use of chemosensors. Upon interaction with targeted analytes, chemosensors produce a distinct response, in some cases a fluorescent or colorimetric signal. The 1,2,3-triazole unit has much potential as a chemical sensor due to its unique photophysical properties. The specificity, selectivity, and signaling mechanism of triazole sensors can be tuned with conjugation in the motif and choice and placement …
Investigation Of Host-Sensitized Luminescence Of Trivalent Lanthanide Doped Yttrium Phosphate Using Vuv Spectroscopy,
2017
Central Washington University
Investigation Of Host-Sensitized Luminescence Of Trivalent Lanthanide Doped Yttrium Phosphate Using Vuv Spectroscopy, Zachary Way
All Master's Theses
Host-sensitized luminescence of yttrium phosphate doped with trivalent lanthanide elements prepared via two synthetic approaches was studied using VUV spectroscopy. A correlation between an unusually intense 150 nm excitation intensity and the ground state energy level of select trivalent lanthanide elements was proposed. Using spectroscopy, the host-to-activator transfer efficiencies of YPO4:Ln3+ (Ln3+ = Sm3+, Eu3+ and Tb3+) were evaluated for two synthetic approaches. Electron-hole pair trapping efficiencies and Sloss values were calculated using published kinetic models.
Detecting Haloacetic Acids Using Chromatography,
2017
University of Alabama in Huntsville
Detecting Haloacetic Acids Using Chromatography, Nathan Perinovic
Summer Community of Scholars Posters (RCEU and HCR Combined Programs)
No abstract provided.
Amino Acid Catabolism In
Staphylococcus Aureus And The Function
Of Carbon Catabolite Repression,
2017
University of Nebraska Medical Center
Amino Acid Catabolism In Staphylococcus Aureus And The Function Of Carbon Catabolite Repression, Cortney R. Halsey, Shulei Lei, Jacqueline K. Wax, Mckenzie K. Lehman, Austin S. Nuxoll, Laurey Steinke, Marat Sadykov, Robert Powers, Paul D. Fey
Department of Chemistry: Faculty Publications
Staphylococcus aureus must rapidly adapt to a variety of carbon and nitrogen sources during invasion of a host. Within a staphylococcal abscess, preferred carbon sources such as glucose are limiting, suggesting that S. aureus survives through the catabolism of secondary carbon sources. S. aureus encodes pathways to catabolize multiple amino acids, including those that generate pyruvate, 2-oxoglutarate, and oxaloacetate. To assess amino acid catabolism, S. aureus JE2 and mutants were grown in complete defined medium containing 18 amino acids but lacking glucose (CDM). A mutation in the gudB gene, coding for glutamate dehydrogenase, which generates 2-oxoglutarate from glutamate, significantly reduced …
Laterally Extended Atomically Precise Graphene Nanoribbons With Improved Electrical Conductivity For Efficient Gas Sensing,
2017
University of Nebraska - Lincoln
Laterally Extended Atomically Precise Graphene Nanoribbons With Improved Electrical Conductivity For Efficient Gas Sensing, Mohammad Mehdi Pour, Andrey Lashkov, Adrian Radocea, Ximeng Liu, Tao Sun, Alexey Lipatov, Rafal A. Korlacki, Mikhail Shekhirev, Narayana R. Aluru, Joseph W. Lyding, Victor Sysoev, Alexander Sinitskii
Department of Chemistry: Faculty Publications
Narrow atomically precise graphene nanoribbons hold great promise for electronic and optoelectronic applications, but the previously demonstrated nanoribbon-based devices typically suffer from low currents and mobilities. In this study, we explored the idea of lateral extension of graphene nanoribbons for improving their electrical conductivity. We started with a conventional chevron graphene nanoribbon, and designed its laterally extended variant. We synthesized these new graphene nanoribbons in solution and found that the lateral extension results in decrease of their electronic bandgap and improvement in the electrical conductivity of nanoribbon-based thin films. These films were employed in gas sensors and an electronic nose …
Nanomaterials As Stationary Phases And Supports In Liquid Chromatography: A Review,
2017
University of Nebraska–Lincoln
Nanomaterials As Stationary Phases And Supports In Liquid Chromatography: A Review, Sandya Beeram, Elliott Rodriguez, Suresh Doddavenkatanna, Zhao Li, Allegra Pekarek, Darin Peev, Kathryn Goerl, Gianfranco Trovato, Tino Hofmann, David S. Hage
Department of Chemistry: Faculty Publications
The development of various nanomaterials over the last few decades has led to many applications for these materials in liquid chromatography (LC). This review will look at the types of nanomaterials that have been incorporated into LC systems and the applications that have been explored for such systems. A number of carbon-based nanomaterials and inorganic nanomaterials have been considered for use in LC, ranging from carbon nanotubes, fullerenes and nanodiamonds to metal nanoparticles and nanostructures based on silica, alumina, zirconia and titanium dioxide. Many ways have been described for incorporating these nanomaterials into LC systems. These methods have included covalent …
A Surface-Stabilized Ozonide Triggers Bromide Oxidation At The Aqueous Solution-Vapour Interface,
2017
Paul Scherrer Institut
A Surface-Stabilized Ozonide Triggers Bromide Oxidation At The Aqueous Solution-Vapour Interface, Luca Artiglia, Jacinta Edebeli, Fabrizio Orlando, Shuzhen Chen, Ming-Tao Lee, Pablo Corral Arroyo, Anina Gilgen, Thorsten Bartels-Rausch, Armin Kleibert, Mario Vazdar, Marcelo Andrea Carignano, Joseph S. Francisco, Paul B. Shepson, Ivan Gladich, Markus Ammann
Department of Chemistry: Faculty Publications
Oxidation of bromide in aqueous environments initiates the formation of molecular halogen compounds, which is important for the global tropospheric ozone budget. In the aqueous bulk, oxidation of bromide by ozone involves a [Br•OOO−] complex as intermediate. Here we report liquid jet X-ray photoelectron spectroscopy measurements that provide direct experimental evidence for the ozonide and establish its propensity for the solution-vapor interface. Theoretical calculations support these findings, showing that water stabilizes the ozonide and lowers the energy of the transition state at neutral pH. Kinetic experiments confirm the dominance of the heterogeneous oxidation route established by this precursor …
Cytotoxic Polyketides With An Oxygen-Bridged Cyclooctadiene Core Skeleton From The Mangrove Endophytic Fungus Phomosis Sp. A818,
2017
University of Nebraska - Lincoln
Cytotoxic Polyketides With An Oxygen-Bridged Cyclooctadiene Core Skeleton From The Mangrove Endophytic Fungus Phomosis Sp. A818, Wei Zhang, Baobing Zhao, Liangcheng Du, Yuemao Shen
Department of Chemistry: Faculty Publications
Plant endophytic microorganisms represent a largely untapped resource for new bioactive natural products. Eight polyketide natural products were isolated from a mangrove endophytic fungus Phomosis sp. A818. The structural elucidation of these compounds revealed that they share a distinct feature in their chemical structures, an oxygen-bridged cyclooctadiene core skeleton. The study on their structure–activity relationship showed that the α,β-unsaturated δ-lactone moiety, as exemplified in compounds 1 and 2, was critical to the cytotoxic activity of these compounds. In addition, compound 4 might be a potential agonist of AMPK (5'-adenosine monophosphate-activated protein kinase).
Chemoselective Alteration Of Fluorophore Scaffolds As A Strategy For The Development Of Ratiometric Chemodosimeters,
2017
University of Nebraska - Lincoln
Chemoselective Alteration Of Fluorophore Scaffolds As A Strategy For The Development Of Ratiometric Chemodosimeters, Xinqi Zhou, Lauren Lesiak, Rui Lai, Jon R. Beck, Jia Zhao, Christian Elowsky, Hui Li, Cliff I. Stains
Department of Chemistry: Faculty Publications
Ratiometric sensors generally couple binding events or chemical reactions at a distal site to changes in the fluorescence of a core fluorophore scaffold. However, such approaches are often hindered by spectral overlap of the product and reactant species. We provide a strategy to design ratiometric sensors that display dramatic spectral shifts by leveraging the chemoselective reactivity of novel functional groups inserted within fluorophore scaffolds. As a proof-of-principle, fluorophores containing a borinate (RF620) or silanediol (SiOH2R) functionality at the bridging position of the xanthene ring system are developed as endogenous H2O2 sensors. Both …
The Future Of Nmr-Based Metabolomics,
2017
University of Wisconsin-Madison
The Future Of Nmr-Based Metabolomics, John L. Markley, Rafael Bruschweiler, Arthur S. Edison, Hamid R. Eghbalnia, Robert Powers, Daniel Raftery, David S. Wishart
Department of Chemistry: Faculty Publications
The two leading analytical approaches to metabolomics are mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. Although currently overshadowed by MS in terms of numbers of compounds resolved, NMR spectroscopy offers advantages both on its own and coupled with MS. NMR data are highly reproducible and quantitative over a wide dynamic range and are unmatched for determining structures of unknowns. NMR is adept at tracing metabolic pathways and fluxes using isotope labels. Moreover, NMR is non-destructive and can be utilized in vivo. NMR results have a proven track record of translating in vitro findings to in vivo clinical …
Resolving The Cofactor-Binding Site In The Proline
Biosynthetic Enzyme Human Pyrroline-5-Carboxylate
Reductase 1,
2017
University of Missouri
Resolving The Cofactor-Binding Site In The Proline Biosynthetic Enzyme Human Pyrroline-5-Carboxylate Reductase 1, Emily M. Christensen, Sagar M. Patel, David A. Korasick, Ashley C. Campbell, Kurt L. Krause, Donald F. Becker, John J. Tanner
Department of Chemistry: Faculty Publications
Pyrroline-5-carboxylate reductase (PYCR) is the final enzyme in proline biosynthesis, catalyzing the NAD(P)H-dependent reduction of [?]1-pyrroline-5-carboxylate (P5C) to proline. Mutations in the PYCR1 gene alter mitochondrial function and cause the connective tissue disorder cutis laxa. Furthermore, PYCR1 is overexpressed in multiple cancers, and the PYCR1 knock-out suppresses tumorigenic growth, suggesting that PYCR1 is a potential cancer target. However, inhibitor development has been stymied by limited mechanistic details for the enzyme, particularly in light of a previous crystallographic study that placed the cofactor-binding site in the C-terminal domain rather than the anticipated Rossmann fold of the N-terminal domain. To fill this …
Indole-Induced Reversion Of Intrinsic
Multiantibiotic Resistance In Lysobacter
Enzymogenes,
2017
Shandong University
Indole-Induced Reversion Of Intrinsic Multiantibiotic Resistance In Lysobacter Enzymogenes, Yong Han, Yan Wang, Yameng Yu, Haotong Chen, Yuemao Shen, Liangcheng Du
Department of Chemistry: Faculty Publications
Lysobacter species are a group of environmental bacteria that are emerging as a new source of antibiotics. One characteristic of Lysobacter is intrinsic resistance to multiple antibiotics, which had not been studied. To understand the resistance mechanism, we tested the effect of blocking two-component regulatory systems (TCSs) on the antibiotic resistance of Lysobacter enzymogenes, a prolific producer of antibiotics. Upon treatment with LED209, an inhibitor of the widespread TCS QseC/QseB, L. enzymogenes produced a large amount of an unknown metabolite that was barely detectable in the untreated culture. Subsequent structural elucidation by nuclear magnetic resonance (NMR) unexpectedly revealed that …
Synthesis Of Cerium Oxide
Nanorods,
2017
University of Nebraska at Lincoln
Synthesis Of Cerium Oxide Nanorods, Chin Li Cheung, Zane Charles Gernhart
Department of Chemistry: Faculty Publications
Cerium oxide nanorods having a variety of aspect ratios can be produced by providing a first mixture that includes a cerium precursor material, and using microwave to heat the first mixture to a first temperature for a period of time to produce first plurality of cerium oxide nanorods having a first range of aspect ratios. A second mixture that includes a cerium precursor material heated using microwave to a second temperature for a period of time to produce second plurality of cerium oxide nanorods having a second range of aspect ratios. The first plurality of cerium oxide nanorods and the …
Human Serine Racemase Structure/Activity Relationship
Studies Provide Mechanistic Insight And Point To Position 84
As A Hot Spot For Β-Elimination Function,
2017
University of Nebraska - Lincoln
Human Serine Racemase Structure/Activity Relationship Studies Provide Mechanistic Insight And Point To Position 84 As A Hot Spot For Β-Elimination Function, David L. Nelson, Greg A. Applegate, Matthew L. Beio, Danielle L. Graham, David B. Berkowitz
Department of Chemistry: Faculty Publications
There is currently great interest in human serine racemase, the enzyme responsible for producing the NMDA co-agonist D-serine. Reported correlation of D-serine levels with disorders including Alzheimer’s disease, ALS, and ischemic brain damage (elevated D-serine) and schizophrenia (reduced D-serine) has further piqued this interest. Reported here is a structure/activity relationship study of position Ser84, the putative re-face base. In the most extreme case of functional reprogramming, the S84D mutant displays a dramatic reversal of β-elimination substrate specificity in favor of L-serine over the normally preferred L-serine-O-sulfate (~1200-fold change in kcat/Km …
Assessment Of Metabolic Changes In Mycobacterium Smegmatis Wild Type And Alr Mutant Strains: Evidence For A New Pathway Of D-Alanine Biosynthesis.,
2017
University of Nebraska - Lincoln
Assessment Of Metabolic Changes In Mycobacterium Smegmatis Wild Type And Alr Mutant Strains: Evidence For A New Pathway Of D-Alanine Biosynthesis., Darrell D. Marshall, Steven Halouska, Denise K. Zinniel, Robert J. Fenton, Katie Kenealy, Harpreet K. Chahal, Govardhan Rathnaiah, Raul G. Barletta, Robert Powers
Department of Chemistry: Faculty Publications
In mycobacteria, D-alanine is an essential precursor for peptidoglycan biosynthesis. The only confirmed enzymatic pathway to form D-alanine is through the racemization of L-alanine by alanine racemase (Alr, EC 5.1.1.1). Nevertheless, the essentiality of Alr in Mycobacterium tuberculosis and Mycobacterium smegmatis for cell survivability in the absence of D-alanine has been a point of controversy with contradictory results reported in the literature. To address this issue, we examined the effects of alr inactivation on the cellular metabolism of M. smegmatis. The M. smegmatis alr insertion mutant TAM23 exhibited essentially identical growth to wild type mc2155 in the …
Transcriptional And Antagonistic Responses Of Biocontrol Strain Lysobacter Enzymogenes Oh11 To The Plant Pathogenic Oomycete Pythium Aphanidermatum,
2017
iangsu Academy of Agricultural Sciences, Nanjing
Transcriptional And Antagonistic Responses Of Biocontrol Strain Lysobacter Enzymogenes Oh11 To The Plant Pathogenic Oomycete Pythium Aphanidermatum, Yangyang Zhao, Guoliang Qian, Yuan Chen, Liangcheng Du, Fengquan Liu
Department of Chemistry: Faculty Publications
Lysobacter enzymogenes is a ubiquitous, beneficial, plant-associated bacterium emerging as a novel biological control agent. It has the potential to become a new source of antimicrobial secondary metabolites such as the Heat-Stable Antifungal Factor (HSAF), which is a broad-spectrum antimycotic with a novel mode of action. However, very little information about how L. enzymogenes detects and responds to fungi or oomycetes has been reported. An in vitro confrontation bioassay between the pathogenic oomycete Pythium aphanidermatum and the biocontrol bacterial strain L. enzymogenes OH11 was used to analyze the transcriptional changes in the bacteria that were induced by the oomycetes. Analysis …
Ion Mobility-Resolved Collision-Induced Dissociation And Electron Transfer Dissociation Of N-Glycopeptides: Gathering Orthogonal Connectivity Information From A Single Mass- Selected Precursor Ion Population,
2017
University of Nebraska-Lincoln
Ion Mobility-Resolved Collision-Induced Dissociation And Electron Transfer Dissociation Of N-Glycopeptides: Gathering Orthogonal Connectivity Information From A Single Mass- Selected Precursor Ion Population, Venkata Kolli, Katherine N. Schumacher, Eric Dodds
Department of Chemistry: Faculty Publications
Glycopeptide-level mass spectrometry (MS) and tandem mass spectrometry (MS/MS) analyses are commonly performed to establish site-specific protein glycosylation profiles that are of central importance to gaining structure-function insights on glycoproteins. Confoundingly, the complete characterization of glycopeptide connectivity usually requires the acquisition of multiple MS/MS fragmentation spectra. Complementary ion fragmentation techniques such as collision-induced dissociation (CID) and electron transfer dissociation (ETD) are often applied in concert to address this need. While structurally informative, the requirement for acquisition of two MS/MS spectra per analyte places considerable limitations upon the breadth and depth of large-scale glycoproteomic inquiry. Here, a previously developed method of …
Phage Display To Identify Functional Resistance Mutations To Rigosertib,
2017
Claremont McKenna College
Phage Display To Identify Functional Resistance Mutations To Rigosertib, Nedim Filipovic
CMC Senior Theses
In vitro protein selection has had major impacts in the field of protein engineering. Traditional screens assay individual proteins for specific function. Selection, however, analyzes a pool of mutants and yields the best variants. Phage display, a successful selection technique, also provides a reliable link between variant phenotype and genotype. It can also be coupled with high throughput sequencing to map protein mutations; potentially highlighting vital mutations in variants. We propose to apply this technique to cancer therapy. RAF, a serine/threonine kinase, is critical for cell regulation in mammals. RAF can be activated by oncogenic RAS, found in over 30% …
Assessment Of Short-Term Toxicity Of Titanium Dioxide Nano Fiber (Tdnf) In Sprague Dawley Rats,
2017
Georgia Southern University
Assessment Of Short-Term Toxicity Of Titanium Dioxide Nano Fiber (Tdnf) In Sprague Dawley Rats, Daniel A. Hunter
College of Graduate Studies: Theses & Dissertations
Nanotechnology is easily becoming one of the fastest growing markets around the globe. Synthetic nanomaterials have many unique chemical and physical properties, mainly due to their huge specific surface area and chemical makeup. Specifically, titanium dioxide (TiO2) nanomaterials have high stability, anticorrosive and photocatalytic properties. These nanomaterials have applications for semiconductor photocatalysis, treatment of water, as a photoactive material in nanocrystalline solar cells, and medicine. However, not much is known about the toxicity of TiO2 in the nanofiber form. The objective of the present study is to investigate the adverse effects associated with acute ingestion of TiO …
Infusion Of Essentail Oils In Agarose Gels To Create Antimicrobial Surfaces,
2017
Honors College, Pace University
Infusion Of Essentail Oils In Agarose Gels To Create Antimicrobial Surfaces, Simran Guron
Honors College Theses
The current use of antibiotics is very excessive in multiple settings, from treating patients to being present in cleaning products. This overuse of antibiotics is resulting in multiple consequences, ranging from having a negative impact on human health to breeding antibiotic-resistant strains of microorganisms. Antimicrobial surfaces are useful today to aid in sterilization, especially in the medical setting. This would help prevent the spread of infection of microorganisms in these settings. In our research, agarose acts as the antimicrobial surface and essential oils would act as the solution incorporated into the surface that has the antimicrobial properties. Agarose is a …
