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Articles 61 - 90 of 91

Full-Text Articles in Biochemistry

Comparative Genomics Of Cluster O Mycobacteriophages, Steven G. Cresawn, Welkin H. Pope, Deborah Jacobs-Sera, Charles A. Bowman, Daniel A. Russell, Rebekah M. Dedrick, Tamarah Adair, Kirk R. Anders, Sarah Ball, David Bollivar, Caroline Breitenberger, Sandra H. Burnett, Kristen Butela, Deanna Byrnes, Sarah Carzo, Dr. Kathleen Cornely, Trevor Cross, Richard L. Daniels, David Dunbar, Ann M. Findley, Chris R. Gissendanner, Urszula P. Golebiewska, Grant A. Hartzog, J. Robert Hatherill, Lee E. Hughes, Chernoh S. Jalloh, Carla De Los Santos, Kevin Ekanem, Sphindile L. Khambule, Rodney A. King, Christina King-Smith, Karen Klyczek, Greg P. Krukonis, Christian Laing, Jonathan S. Lapin, A. Javier Lopez, Sipho M. Mkhwanazi, Sally D. Molloy, Deborah Moran, Vanisha Munsamy, Eddie Pacey, Ruth Plymale, Marianne Poxleitner, Nathan Reyna, Joel F. Schildbach, Joseph Stukey, Sarah E. Taylor, Vassie C. Ware, Amanda L. Wellmann, Daniel Westholm, Donna Wodarski, Michelle Zajko, Thabiso S. Zikalala, Roger W. Hendrix, Graham F. Hatfull Mar 2015

Comparative Genomics Of Cluster O Mycobacteriophages, Steven G. Cresawn, Welkin H. Pope, Deborah Jacobs-Sera, Charles A. Bowman, Daniel A. Russell, Rebekah M. Dedrick, Tamarah Adair, Kirk R. Anders, Sarah Ball, David Bollivar, Caroline Breitenberger, Sandra H. Burnett, Kristen Butela, Deanna Byrnes, Sarah Carzo, Dr. Kathleen Cornely, Trevor Cross, Richard L. Daniels, David Dunbar, Ann M. Findley, Chris R. Gissendanner, Urszula P. Golebiewska, Grant A. Hartzog, J. Robert Hatherill, Lee E. Hughes, Chernoh S. Jalloh, Carla De Los Santos, Kevin Ekanem, Sphindile L. Khambule, Rodney A. King, Christina King-Smith, Karen Klyczek, Greg P. Krukonis, Christian Laing, Jonathan S. Lapin, A. Javier Lopez, Sipho M. Mkhwanazi, Sally D. Molloy, Deborah Moran, Vanisha Munsamy, Eddie Pacey, Ruth Plymale, Marianne Poxleitner, Nathan Reyna, Joel F. Schildbach, Joseph Stukey, Sarah E. Taylor, Vassie C. Ware, Amanda L. Wellmann, Daniel Westholm, Donna Wodarski, Michelle Zajko, Thabiso S. Zikalala, Roger W. Hendrix, Graham F. Hatfull

Chemistry & Biochemistry Faculty Publications

Mycobacteriophages – viruses of mycobacterial hosts – are genetically diverse but morphologically are all classified in the Caudovirales with double-stranded DNA and tails. We describe here a group of five closely related mycobacteriophages – Corndog, Catdawg, Dylan, Firecracker, and YungJamal – designated as Cluster O with long flexible tails but with unusual prolate capsids. Proteomic analysis of phage Corndog particles, Catdawg particles, and Corndog-infected cells confirms expression of half of the predicted gene products and indicates a non-canonical mechanism for translation of the Corndog tape measure protein. Bioinformatic analysis identifies 8–9 strongly predicted SigA promoters and all five Cluster O …

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Redox-Dependent Stability, Protonation, And Reactivity Of Cysteine-Bound Heme Proteins, Fangfang Zhong, George P. Lisi, Daniel P. Collins, John H. Dawson, Ekaterina V. Pletneva Jan 2014

Redox-Dependent Stability, Protonation, And Reactivity Of Cysteine-Bound Heme Proteins, Fangfang Zhong, George P. Lisi, Daniel P. Collins, John H. Dawson, Ekaterina V. Pletneva

Dartmouth Scholarship

Cysteine-bound hemes are key components of many enzymes and biological sensors. Protonation (deprotonation) of the Cys ligand often accompanies redox transformations of these centers. To characterize these phenomena, we have engineered a series of Thr78Cys/Lys79Gly/Met80X mutants of yeast cytochrome c (cyt c) in which Cys78 becomes one of the axial ligands to the heme. At neutral pH, the protonation state of the coordinated Cys differs for the ferric and ferrous heme species, with Cys binding as a thiolate and a thiol, respectively. Analysis of redox-dependent stability and alkaline transitions of these model proteins, as well as comparisons to Cys …

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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 Jan 2014

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 …

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Killerflip: A Novel Lytic Peptide Specifically Inducing Cancer Cell Death, B Pennarun, G. Gaidos, O Bucur, A Tinari Oct 2013

Killerflip: A Novel Lytic Peptide Specifically Inducing Cancer Cell Death, B Pennarun, G. Gaidos, O Bucur, A Tinari

Dartmouth Scholarship

One of the objectives in the development of effective cancer therapy is induction of tumor-selective cell death. Toward this end, we have identified a small peptide that, when introduced into cells via a TAT cell-delivery system, shows a remarkably potent cytoxicity in a variety of cancer cell lines and inhibits tumor growth in vivo, whereas sparing normal cells and tissues. This fusion peptide was named killer FLIP as its sequence was derived from the C-terminal domain of c-FLIP, an anti-apoptotic protein. Using structure activity analysis, we determined the minimal bioactive core of killerFLIP, namely killerFLIP-E. Structural analysis of cells using …

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Bioengineered Lysozyme Reduces Bacterial Burden And Inflammation In A Murine Model Of Mucoid Pseudomonas Aeruginosa Lung Infection, Charlotte C. Teneback, Thomas C. Scanlon, Matthew J. Wargo, Jenna L. Bement, Karl E. Griswold, Laurie W. Leclair Aug 2013

Bioengineered Lysozyme Reduces Bacterial Burden And Inflammation In A Murine Model Of Mucoid Pseudomonas Aeruginosa Lung Infection, Charlotte C. Teneback, Thomas C. Scanlon, Matthew J. Wargo, Jenna L. Bement, Karl E. Griswold, Laurie W. Leclair

Dartmouth Scholarship

The spread of drug-resistant bacterial pathogens is a growing global concern and has prompted an effort to explore potential adjuvant and alternative therapies derived from nature's repertoire of bactericidal proteins and peptides. In humans, the airway surface liquid layer is a rich source of antibiotics, and lysozyme represents one of the most abundant and effective antimicrobial components of airway secretions. Human lysozyme is active against both Gram-positive and Gram-negative bacteria, ac

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Synthesis And Immunological Evaluation Of Type I, Type Ii, And Gamma Delta Nkt Cell Antigens, Brian L. Anderson May 2013

Synthesis And Immunological Evaluation Of Type I, Type Ii, And Gamma Delta Nkt Cell Antigens, Brian L. Anderson

Theses and Dissertations

The purpose of the immune system is to protect our bodies from infection. One way it accomplishes this task is through the presentation of foreign pathogens to NKT cells. After an antigen is presented to the T cell receptor, activated NKT cells quickly release soluble chemical signals, termed chemokines and cytokines, that modulate the response of the immune system. Due to the immunological relevance of NKT cell activation, we developed and synthesised non-natural analogs of immunostimulatory type I, II, and gamma delta NKT cell antigens. The immunological evaluations of these analogs resulted in identification of sulfatide as a gamma delta …

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Integrating Art And Science In Undergraduate Education, Daniel Gurnon Feb 2013

Integrating Art And Science In Undergraduate Education, Daniel Gurnon

Chemistry & Biochemistry Faculty Publications

The prevailing vision for undergraduate science education includes increased collaboration among teachers of science, technology, engineering and math (STEM) and an overhaul of introductory courses [1]–[4]. But by staying within the borders of STEM, are we overlooking connections between the arts and innovative science? Likewise, are we missing an important opportunity to inspire and inform nonscientists? Here we explore how weaving the visual arts into a science curriculum can both help develop scientific imagination and engage nonscientists. As an example, we describe a recent collaboration between artists and scientists to create a series of science-inspired sculptures.

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Membrane Surface Charges Attracted Protons Are Not Relevant To Proton Motive Force, James Weifu Lee Jan 2013

Membrane Surface Charges Attracted Protons Are Not Relevant To Proton Motive Force, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

[First Paragraph] Only a half-century ago, British scientist Peter Mitchell proposed the conceptual scheme known as "chemiosmotic theory" that identified the role of proton coupling in the formation of ATP in cells [1,2]. Mitchell's delocalized proton-coupling chemiosmotic theory was initially quite controversial. But it would win for him the Nobel Prize in Chemistry in 1978. However, questions about Mitchell's chemiosmotic hypothesis have never gone away and a number of credible studies indicated the full extent of Mitchell's idea didn't always hold up to experience.

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N-Terminal Domain Of Vacuolar Snare Vam7p Promotes Trans-Snare Complex Assembly, Hao Xu, William T. Wickner Sep 2012

N-Terminal Domain Of Vacuolar Snare Vam7p Promotes Trans-Snare Complex Assembly, Hao Xu, William T. Wickner

Dartmouth Scholarship

SNARE-dependent membrane fusion in eukaryotic cells requires that the heptad-repeat SNARE domains from R- and Q-SNAREs, anchored to apposed membranes, assemble into four-helix coiled-coil bundles. In addition to their SNARE and transmembrane domains, most SNAREs have N-terminal domains (N-domains), although their functions are unclear. The N-domain of the yeast vacuolar Qc-SNARE Vam7p is a binding partner for the homotypic fusion and vacuole protein sorting complex (a master regulator of vacuole fusion) and has Phox homology, providing a phosphatidylinositol 3-phosphate (PI3P)-specific membrane anchor. We now report that this Vam7p N-domain has yet another role, one that does not depend on its …

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Planning Combinatorial Disulfide Cross-Links For Protein Fold Determination, Fei Xiong, Alan M Friedman, Chris Bailey-Kellogg Nov 2011

Planning Combinatorial Disulfide Cross-Links For Protein Fold Determination, Fei Xiong, Alan M Friedman, Chris Bailey-Kellogg

Dartmouth Scholarship

Fold recognition techniques take advantage of the limited number of overall structural organizations, and have become increasingly effective at identifying the fold of a given target sequence. However, in the absence of sufficient sequence identity, it remains difficult for fold recognition methods to always select the correct model. While a native-like model is often among a pool of highly ranked models, it is not necessarily the highest-ranked one, and the model rankings depend sensitively on the scoring function used. Structure elucidation methods can then be employed to decide among the models based on relatively rapid biochemical/biophysical experiments.

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A Lipid-Anchored Snare Supports Membrane Fusion, Hao Xu, Michael Zick, William T. Wickner, Youngsoo Jun Oct 2011

A Lipid-Anchored Snare Supports Membrane Fusion, Hao Xu, Michael Zick, William T. Wickner, Youngsoo Jun

Dartmouth Scholarship

Intracellular membrane fusion requires R-SNAREs and Q-SNAREs to assemble into a four-helical parallel coiled-coil, with their hydrophobic anchors spanning the two apposed membranes. Based on the fusion properties of chemically defined SNARE- proteoliposomes, it has been proposed that the assembly of this helical bundle transduces force through the entire bilayer via the transmembrane SNARE anchor domains to drive fusion. However, an R-SNARE, Nyv1p, with a genetically engineered lipid anchor that spans half of the bilayer suffices for the fusion of isolated vacuoles, although this organelle has other R-SNAREs. To demonstrate unequivocally the fusion activity of lipid-anchored Nyv1p, we reconstituted proteoliposomes …

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Characterization Of Esterase Activity From The Bacteria, Francisella Tularensis, The Causative Agent Of Tularemia, Leigh Anna Weston May 2011

Characterization Of Esterase Activity From The Bacteria, Francisella Tularensis, The Causative Agent Of Tularemia, Leigh Anna Weston

Undergraduate Honors Thesis Collection

Francisella tularensis is the bacteria responsible for causing the disease tularemia and is listed as one of the top three-biowarfare agents. Among the proteins essential to the virulence and infectivity of F.tularensis are multiple esterases, which are enzymes that break down various ester, thioester, and amide bonds. In this project, the catalytic activity, substrate speci fi city, and structure of a putative esterase from F.tularensis was studied. Latent fluorophores based on the molecule, fluorescein, were unmasked by the enzymatic activity of the esterase and the increase in fluorescence was measured over time to determine how well the e tcrase recognized …

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An Assessment Of Stable Hydrogen-Isotope Analysis Methods To Assign Geographic Origin To Migratory Red-Tailed Hawks (Buteo Jamaicensis), Carla Marie Ahlschwede May 2011

An Assessment Of Stable Hydrogen-Isotope Analysis Methods To Assign Geographic Origin To Migratory Red-Tailed Hawks (Buteo Jamaicensis), Carla Marie Ahlschwede

Department of Environmental Studies: Undergraduate Student Theses

Stable-hydrogen isotopes are becoming an increasingly popular method of studying migratory birds, though sample preparation methods may affect results.  In this study I examined feathers from red-tailed hawks (Buteo jamaicensis) to determine the relationship between measure of δD due to inter-feather variation or drying methods, assessed the accuracy of results by using two birds of known-origin and estimated possible natal origins of migratory red-tailed hawks.  Two feathers per individual were taken from 81 wild hawks caught at Hitchcock Nature Center near Crescent IA and from 2 rescued red-tailed hawks, Raptor Recovery Nebraska near Eagle, NE. 119 of the …

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Advanced Statistical Methods For Biochemical And Forensic Applications Of Raman Spectroscopy, Vitali Sikirzhytski Jan 2011

Advanced Statistical Methods For Biochemical And Forensic Applications Of Raman Spectroscopy, Vitali Sikirzhytski

Legacy Theses & Dissertations (2009 - 2024)

This work is dedicated to the development and application of advanced statistical methods for biochemical and forensic applications of Raman spectroscopy. We developed a new concept of multidimensional Raman signatures for forensic identification of body fluid traces, which was successfully applied to the study of dried blood, semen, saliva, sweat and vaginal fluid stains. Several alternative advanced chemometric techniques were also successfully tested for the problems of pure body fluids discrimination and mixture analysis. Studies of body fluid mixtures with low blood and semen concentrations indicated that the detection limit of a minor contributor was as low as a few …

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Conformation And Ion Transport Of Neuronal Uncoupling Proteins: Ucp2, Ucp4, And Ucp5, Tuan Hoang Jan 2011

Conformation And Ion Transport Of Neuronal Uncoupling Proteins: Ucp2, Ucp4, And Ucp5, Tuan Hoang

Theses and Dissertations (Comprehensive)

Located in the inner mitochondrial membrane of brown adipose tissue, uncoupling protein -1 (UCP1) dissipates the proton electrochemical gradient, causing reduction in the rate of ATP synthesis, and generates heat by non-shivering thermogenesis. Three other UCP homologs (UCP2, UCP4 and UCP5), expressed in neurons, are suggested to have potential roles in the function and protection of the central nervous system (CNS). Up to date, structural information for UCPs still remains limited. Extensive biochemical studies on UCP2 have provided adequate evidence for its participation in proton and anion transport. So far, no functional studies in proteoliposome systems have been performed on …

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Physical Interaction Between Vivid And White Collar Complex Regulates Photoadaptation In Neurospora, Chen-Hui H. Chen, Bradley S. Demay, Amy S. Gladfelter, Jay Dunlap, Jennifer J. Loros Sep 2010

Physical Interaction Between Vivid And White Collar Complex Regulates Photoadaptation In Neurospora, Chen-Hui H. Chen, Bradley S. Demay, Amy S. Gladfelter, Jay Dunlap, Jennifer J. Loros

Dartmouth Scholarship

Photoadaptation, the ability to attenuate a light response on prolonged light exposure while remaining sensitive to escalating changes in light intensity, is essential for organisms to decipher time information appropriately, yet the underlying molecular mechanisms are poorly understood. In Neurospora crassa, VIVID (VVD), a small LOV domain containing blue-light photoreceptor protein, affects photoadaptation for most if not all light-responsive genes. We report that there is a physical interaction between VVD and the white collar complex (WCC), the primary blue-light photoreceptor and the transcription factor complex that initiates light-regulated transcriptional responses in Neurospora. Using two previously characterized VVD mutants, we show …

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Genetic And Molecular Characterization Of A Cryptochrome From The Filamentous Fungus Neurospora Crassa, Allan C. Froehlich, Chen-Hui Chen, William J. Belden, Cornelia Madeti Mar 2010

Genetic And Molecular Characterization Of A Cryptochrome From The Filamentous Fungus Neurospora Crassa, Allan C. Froehlich, Chen-Hui Chen, William J. Belden, Cornelia Madeti

Dartmouth Scholarship

In plants and animals, cryptochromes function as either photoreceptors or circadian clock components. We have examined the cryptochrome from the filamentous fungus Neurospora crassa and demonstrate that Neurospora cry encodes a DASH-type cryptochrome that appears capable of binding flavin adenine dinucleotide (FAD) and methenyltetrahydrofolate (MTHF). The cry transcript and CRY protein levels are strongly induced by blue light in a wc-1-dependent manner, and cry transcript is circadianly regulated, with a peak abundance opposite in phase to frq. Neither deletion nor overexpression of cry appears to perturb the free-running circadian clock. However, cry disruption knockout mutants show a small phase delay …

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Photocycloaddition Of Allenes, Crystal Ward Nov 2008

Photocycloaddition Of Allenes, Crystal Ward

Theses and Dissertations

For the past ten years the Fleming research group has been involved in the research of allene compounds. We have explored the synthesis of allenes as well as several reactions involving allenes, such as oxidation and nitrene addition. Recently, we have explored the synthesis and photochemistry of allenic alcohols tethered to silicon. There are literature examples using allenes in synthesis, but very few examples exist using allenes in photochemical cycloaddition reactions. We have found that a diisopropylallenyloxy(cinnamyloxy)silane derivative undergoes [2+2] photochemical cycloaddition to produce a cyclobutylsilane product when irradiated for 60-75 minutes.

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A Conserved Cam- And Radial Spoke–Associated Complex Mediates Regulation Of Flagellar Dynein Activity, Erin E. Dymek, Elizabeth F. Smith Nov 2007

A Conserved Cam- And Radial Spoke–Associated Complex Mediates Regulation Of Flagellar Dynein Activity, Erin E. Dymek, Elizabeth F. Smith

Dartmouth Scholarship

For virtually all cilia and eukaryotic flagella, the second messengers calcium and cyclic adenosine monophosphate are implicated in modulating dynein- driven microtubule sliding to regulate beating. Calmodulin (CaM) localizes to the axoneme and is a key calcium sensor involved in regulating motility. Using immunoprecipitation and mass spectrometry, we identify members of a CaM-containing complex that are involved in regulating dynein activity. This complex includes flagellar-associated protein 91 (FAP91), which shares considerable sequence similarity to AAT-1, a protein originally identified in testis as an A-kinase anchor protein (AKAP)- binding protein. FAP91 directly interacts with radial spoke protein 3 (an AKAP), which …

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The Development Of A Gc/Ms Protocol For The Analysis Of Polysaccharides In Echinacea Purpurea, Michaela Knapp Apr 2007

The Development Of A Gc/Ms Protocol For The Analysis Of Polysaccharides In Echinacea Purpurea, Michaela Knapp

Undergraduate Theses and Capstone Projects

Echinacea purpurea is an herbal supplement used to reduce symptoms of common colds and flu-like illnesses. As of right now, it is not well understood what chemical components in the plant are immunologically active. The four main potentially immunologically active chemical components in E. purpurea are caffeic acid derivatives, alkamides, polyacetylenes, and polysaccharides. In this investigation, a protocol was developed in an attempt to identify polysaccharides present in Puritan’s Pride E. purpurea (aerial) “non-irradiated” herbal supplement First, an estimate of the crude total polysaccharide content in Puritan’s Pride and in a ChromaDex certified botanical standard (E. purpurea -powdered root) was …

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Dna-Templated Nanomaterials, Hector Alejandro Becerril-Garcia Apr 2007

Dna-Templated Nanomaterials, Hector Alejandro Becerril-Garcia

Theses and Dissertations

Nanomaterials display interesting physical and chemical properties depending on their shape, size and composition. Self assembly is an intriguing route to producing nanomaterials with controllable compositions and morphologies. DNA has been used to guide the self assembly of materials, resulting in: (1) metal nanowires; (2) metal or semiconductor nanorods; (3) carbon nanotubes; and (4) semiconductor, metal or biological nanoparticles. My work expands the range of DNA templated nanomaterials and develops novel ways of using DNA to pattern nanostructures on surfaces. I have performed the first synthesis of silver nanorods on single stranded DNA, an attractive material for localizing DNA coupled …

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The Yeast Orthologue Of Grasp65 Forms A Complex With A Coiled-Coil Protein That Contributes To Er To Golgi Traffic, Rudy Behnia, Francis A. Barr, John J. Flanagan, Charles Barlowe, Sean Munro Jan 2007

The Yeast Orthologue Of Grasp65 Forms A Complex With A Coiled-Coil Protein That Contributes To Er To Golgi Traffic, Rudy Behnia, Francis A. Barr, John J. Flanagan, Charles Barlowe, Sean Munro

Dartmouth Scholarship

The mammalian Golgi protein GRASP65 is required in assays that reconstitute cisternal stacking and vesicle tethering. Attached to membranes by an N-terminal myristoyl group, it recruits the coiled-coil protein GM130. The relevance of this system to budding yeasts has been unclear, as they lack an obvious orthologue of GM130, and their only GRASP65 relative (Grh1) lacks a myristoylation site and has even been suggested to act in a mitotic checkpoint. In this study, we show that Grh1 has an N-terminal amphipathic helix that is N-terminally acetylated and mediates association with the cis-Golgi. We find that Grh1 forms a complex with …

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Photoreductive Dissolution Of Ferrihydrite By Methanesulfinic Acid: Evidence Of A Direct Link Between Dimethylsulfide And Iron-Bioavailability, Anne M. Johansen, Jennifer M. Key Jul 2006

Photoreductive Dissolution Of Ferrihydrite By Methanesulfinic Acid: Evidence Of A Direct Link Between Dimethylsulfide And Iron-Bioavailability, Anne M. Johansen, Jennifer M. Key

All Faculty Scholarship for the College of the Sciences

Within open‐ocean regions where excess macronutrients are present, phytoplankton growth is limited by the bioavailability of iron supplied to these areas primarily within atmospheric aerosols of crustal origin. However, processes that control the abundance of biologically accessible iron in these aerosols are largely unknown. Here we show that dissolution of ferrihydrite, a surrogate iron(oxy)hydroxide phase found in atmospheric waters, is enhanced in the presence of methanesulfinic acid (MSIA, CH3SO2H, a dimethylsulfide (DMS) oxidation intermediate) in laboratory irradiation experiments with aqueous suspensions that simulate marine aerosol particles. The increased release of soluble Fe(II) is attributed to a …

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Examination Of Technologies For Student-Generated Work In A Peer-Led, Peer-Review Instructional Environment, Brian P. Coppola, Alan L. Kiste Aug 2004

Examination Of Technologies For Student-Generated Work In A Peer-Led, Peer-Review Instructional Environment, Brian P. Coppola, Alan L. Kiste

Chemistry and Biochemistry

There is a growing literature demonstrating the effectiveness of using computer environments to assist students’ in visualizing science and mathematics concepts. However, with many of these computerized learning environments, students do not have the option of manipulating the environment. Instead, they are presented with pre-made visualizations. Enabling students to display their understanding through multiple representational forms is more interesting. In our peer-led, peer-review environment, students generate a complex, literature-based, multimedia text on which their final examination is based. However, there are great time and personnel costs in this design. Collaborating with SRI Inc., we are addressing these demands via the …

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Disulfide Bond Formation Involves A Quinhydrone-Type Charge–Transfer Complex, James Regeimbal, Stefan Gleiter, Bernard L. Trumpower, Chang-Ang Yu Nov 2003

Disulfide Bond Formation Involves A Quinhydrone-Type Charge–Transfer Complex, James Regeimbal, Stefan Gleiter, Bernard L. Trumpower, Chang-Ang Yu

Dartmouth Scholarship

The chemistry of disulfide exchange in biological systems is well studied. However, the detailed mechanism of how oxidizing equivalents are derived to form disulfide bonds in proteins is not clear. In prokaryotic organisms, it is known that DsbB delivers oxidizing equivalents through DsbA to secreted proteins. DsbB becomes reoxidized by reducing quinones that are part of the membrane-bound electron-transfer chains. It is this quinone reductase activity that links disulfide bond formation to the electron transport system. We show here that purified DsbB contains the spectral signal of a quinhydrone, a charge-transfer complex consisting of a hydroquinone and a quinone in …

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A Novel Iron-Regulated Metal Transporter From Plants Identified By Functional Expression In Yeast., David Eide, Margaret Broderius, Jeanette Fett, Mary Lou Guerinot May 1996

A Novel Iron-Regulated Metal Transporter From Plants Identified By Functional Expression In Yeast., David Eide, Margaret Broderius, Jeanette Fett, Mary Lou Guerinot

Dartmouth Scholarship

Iron is an essential nutrient for virtually all organisms. The IRT1 (iron-regulated transporter) gene of the plant Arabidopsis thaliana, encoding a probable Fe(II) transporter, was cloned by functional expression in a yeast strain defective for iron uptake. Yeast expressing IRT1 possess a novel Fe(II) uptake activity that is strongly inhibited by Cd. IRT1 is predicted to be an integral membrane protein with a metal-binding domain. Data base comparisons and Southern blot analysis indicated that IRT1 is a member of a gene family in Arabidopsis. Related sequences were also found in the genomes of rice, yeast, nematodes, and humans. In Arabidopsis, …

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Binding Of Matrix Attachment Regions To Lamin Polymers Involves Single-Stranded Regions And The Minor Groove., M. E. Eva Ludérus, Jan L. Den Blaauwen, Oncko J. De Smit, Duane A. Compton, Roel Van Driel Jan 1994

Binding Of Matrix Attachment Regions To Lamin Polymers Involves Single-Stranded Regions And The Minor Groove., M. E. Eva Ludérus, Jan L. Den Blaauwen, Oncko J. De Smit, Duane A. Compton, Roel Van Driel

Dartmouth Scholarship

Chromatin in eukaryotic nuclei is thought to be partitioned into functional loop domains that are generated by the binding of defined DNA sequences, named MARs (matrix attachment regions), to the nuclear matrix. We have previously identified B-type lamins as MAR-binding matrix components (M. E. E. Ludérus, A. de Graaf, E. Mattia, J. L. den Blaauwen, M. A. Grande, L. de Jong, and R. van Driel, Cell 70:949-959, 1992). Here we show that A-type lamins and the structurally related proteins desmin and NuMA also specifically bind MARs in vitro. We studied the interaction between MARs and lamin polymers in molecular detail …

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Hepatic Lipase Treatment Of Chylomicron Remnants Increases Exposure Of Apolipoprotein E, Dawn L. Brasaemle, Kathleen Cornely-Moss, André Bensadoun Mar 1993

Hepatic Lipase Treatment Of Chylomicron Remnants Increases Exposure Of Apolipoprotein E, Dawn L. Brasaemle, Kathleen Cornely-Moss, André Bensadoun

Chemistry & Biochemistry Faculty Publications

The consequences of hepatic lipase treatment of chylomicron remnants were studied. Rats were fed corn oil to induce production and secretion of chylomicrons and were then injected with polyclonal antiserum raised against hepatic lipase to specifically and quantitatively inhibit hepatic lipase activity in vivo. A fraction enriched in chylomicron remnants was isolated from rat plasma by a brief centrifugation step that preferentially isolates triglyceride-rich apolipoprotein (apo) B-48-containing lipoproteins. The chylomicron remnants were then treated with hepatic lipase in vitro, or incubated under identical conditions in the absence of enzyme (control incubations). Hepatic lipase-treated and control chylomicron remnants were isolated by …

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The Enzymatic Oxidation Of Aldehydes By Xanthine Oxidase, Duane Beal Gregory Jun 1970

The Enzymatic Oxidation Of Aldehydes By Xanthine Oxidase, Duane Beal Gregory

All Master's Theses

As early as sixty years ago, the existence of an enzyme from mammalian tissues which catalyzed the oxidation of xanthine and hypoxanthine was recognized. The name given the enzyme was derived from its earliest recognized action, hence xanthine oxidase. Although little is known about the biological functions of the enzyme, the high affinity shown for xanthine and hypoxanthine may indicate that these are the most significant substrates biologically.

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Pigments And Neurogenic Secretions Of Dermasterias Imbricata, Stephen Edward Davis Aug 1969

Pigments And Neurogenic Secretions Of Dermasterias Imbricata, Stephen Edward Davis

All Master's Theses

Identification of the compound from the asteroid Dermasterias imbricata that evokes the swimming response in the sea anemone Stomphia coccinea was attempted. Although the compound was not identified, it was postulated to be a low molecular weight highly polar molecule of possible carbohydrate origin.

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