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Biochemistry, Biophysics, and Structural Biology

2006

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Articles 31 - 60 of 206

Full-Text Articles in Life Sciences

Hyaluronidase Expression Induces Prostate Tumor Metastasis In An Orthotopic Mouse Model, Joy L. Kovar, Mark A. Johnson, William M. Volcheck, Jiyan Chen, Melanie A. Simpson Oct 2006

Hyaluronidase Expression Induces Prostate Tumor Metastasis In An Orthotopic Mouse Model, Joy L. Kovar, Mark A. Johnson, William M. Volcheck, Jiyan Chen, Melanie A. Simpson

Department of Biochemistry: Faculty Publications

Molecular mechanisms of prostate cancer progression are frequently studied in mice by orthotopic injection of aggressive cell lines, which yield primary tumors that spontaneously metastasize to lymph nodes. In this report, we characterized the human prostate carcinoma cell line 22Rv1 in an orthotopic system and evaluated the functional relevance of the hyaluronidase Hyal1, a correlate of invasive human prostate cancer, to progression in this model. To provide real-time insights into these processes, we first validated use of an epidermal growth factorconjugated fluorophore to illuminate orthotopic prostate tumors and their metastases in whole animal imaging. Animals receiving intraprostatic injections were tracked …

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Methods And Materials For Making And Using Transgenic Dicamba-Degrading Organisms, Donald P. Weeks, Xiao-Zhuo Wang, Patricia L. Herman Sep 2006

Methods And Materials For Making And Using Transgenic Dicamba-Degrading Organisms, Donald P. Weeks, Xiao-Zhuo Wang, Patricia L. Herman

Department of Biochemistry: Faculty Publications

The invention provides isolated and at least partially-purified dicamba-degrading enzymes, isolated DNA molecules coding for dicamba-degrading enzymes, DNA constructs coding for dicamba-degrading enzymes, transgenic host cells comprising DNA coding for dicamba-degrading enzymes, and transgenic plants and plant parts comprising one or more cells comprising DNA coding for dicamba-degrading enzymes. Expression of the dicamba-degrading enzymes results in the production of dicamba-degrading organisms, including dicamba-tolerant plants. The invention further provides a method of controlling weeds in a field containing the transgenic dicamba-tolerant plants of the invention and a method of decontaminating a material containing dicamba comprising applying an effective amount of a …

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Two Glucose-Sensing Pathways Converge On Rgt1 To Regulate Expression Of Glucose Transporter Genes In Saccharomyces Cerevisiae, Jeong-Ho Kim, Mark Johnston Sep 2006

Two Glucose-Sensing Pathways Converge On Rgt1 To Regulate Expression Of Glucose Transporter Genes In Saccharomyces Cerevisiae, Jeong-Ho Kim, Mark Johnston

Faculty Publications

The yeast Saccharomyces cerevisiae deploys two different types of glucose sensors on its cell surface that operate in distinct glucose signaling pathways: the glucose transporter-like Snf3 and Rgt2 proteins and the Gpr1 receptor that is coupled to Gpa2, a G-protein α subunit. The ultimate target of the Snf3/Rgt2 pathway is Rgt1, a transcription factor that regulates expression of HXT genes encoding glucose transporters. We have found that the cAMP-dependent protein kinase A (PKA), which is activated by the Gpr1/Gpa2 glucose-sensing pathway and by a glucose-sensing pathway that works through Ras1 and Ras2, catalyzes phosphorylation of Rgt1 and regulates its function. …

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The Structure Of Escherichia Coli Signal Recognition Particle Revealed By Scanning Transmission Electron Microscopy, Lain L. Mainprize, Daniel R. Beniac, Elena Falkovskaia, Robert M. Cleverley, Lila Gierasch, F. Peter Ottensmeyer, David W. Andrews Sep 2006

The Structure Of Escherichia Coli Signal Recognition Particle Revealed By Scanning Transmission Electron Microscopy, Lain L. Mainprize, Daniel R. Beniac, Elena Falkovskaia, Robert M. Cleverley, Lila Gierasch, F. Peter Ottensmeyer, David W. Andrews

Lila Gierasch

Structural studies on various domains of the ribonucleoprotein signal recognition particle (SRP) have not converged on a single complete structure of bacterial SRP consistent with the biochemistry of the particle. We obtained a three-dimensional structure for Escherichia coli SRP by cryoscanning transmission electron microscopy and mapped the internal RNA by electron spectroscopic imaging. Crystallographic data were fit into the SRP reconstruction, and although the resulting model differed from previous models, they could be rationalized by movement through an interdomain linker of Ffh, the protein component of SRP. Fluorescence resonance energy transfer experiments determined interdomain distances that were consistent with our …

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Erv26p Directs Pro-Alkaline Phosphatase Into Endoplasmic Reticulum–Derived Coat Protein Complex Ii Transport Vesicles, Catherine A. Bue, Christine M. Bentivoglio, Charles Barlowe Sep 2006

Erv26p Directs Pro-Alkaline Phosphatase Into Endoplasmic Reticulum–Derived Coat Protein Complex Ii Transport Vesicles, Catherine A. Bue, Christine M. Bentivoglio, Charles Barlowe

Dartmouth Scholarship

Secretory proteins are exported from the endoplasmic reticulum (ER) in transport vesicles formed by the coat protein complex II (COPII). We detected Erv26p as an integral membrane protein that was efficiently packaged into COPII vesicles and cycled between the ER and Golgi compartments. The erv26Δ mutant displayed a selective secretory defect in which the pro-form of vacuolar alkaline phosphatase (pro-ALP) accumulated in the ER, whereas other secretory proteins were transported at wild-type rates. In vitro budding experiments demonstrated that Erv26p was directly required for packaging of pro-ALP into COPII vesicles. Moreover, Erv26p was detected in a specific complex with pro-ALP …

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In Vivo Mature Immunological Synapses Forming Smacs Mediate Clearance Of Virally Infected Astrocytes From The Brain, Carlos Barcia, Clare Thomas, James Curtin, Gwendalyn King, Kolja Wawrowsky, Marianela Candolfi, Weidong Xiong, Chunyan Liu, Kurt Kroeger, Olivier Boyer, Jerzy Kupiec-Weglinski, David Klatzmann, Maria Castro, Pedro Lowenstein Sep 2006

In Vivo Mature Immunological Synapses Forming Smacs Mediate Clearance Of Virally Infected Astrocytes From The Brain, Carlos Barcia, Clare Thomas, James Curtin, Gwendalyn King, Kolja Wawrowsky, Marianela Candolfi, Weidong Xiong, Chunyan Liu, Kurt Kroeger, Olivier Boyer, Jerzy Kupiec-Weglinski, David Klatzmann, Maria Castro, Pedro Lowenstein

Articles

The microanatomy of immune clearance of infected brain cells remains poorly understood. Immunological synapses are essential anatomical structures that channel information exchanges between T cell–antigen-presenting cells (APC) during the priming and effector phases of T cells' function, and during natural killer–target cell interactions. The hallmark of immunological synapses established by T cells is the formation of the supramolecular activation clusters (SMACs), in which adhesion molecules such as leukocyte function-associated antigen 1 segregate to the peripheral domain of the immunological synapse (p-SMAC), which surrounds the T cell receptor–rich or central SMAC (c-SMAC). The inability so far to detect SMAC formation in …

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Peroxidase-Dependent Apoplastic Oxidative Burst In Arabidopsis Required For Pathogen Resistance, Laurence V. Bindschedler, Julia Dewdney, Kris A. Blee, Julie M. Stone, Tsuneaki Asai, Julia Plotnikov, Carine Denoux, Tezni Hayes, Chris Gerrish, Dewi R. Davies, Frederick M. Ausubel, G. Paul Bolwell Sep 2006

Peroxidase-Dependent Apoplastic Oxidative Burst In Arabidopsis Required For Pathogen Resistance, Laurence V. Bindschedler, Julia Dewdney, Kris A. Blee, Julie M. Stone, Tsuneaki Asai, Julia Plotnikov, Carine Denoux, Tezni Hayes, Chris Gerrish, Dewi R. Davies, Frederick M. Ausubel, G. Paul Bolwell

Department of Biochemistry: Faculty Publications

The oxidative burst is an early response to pathogen attack leading to the production of reactive oxygen species (ROS) including hydrogen peroxide. Two major mechanisms involving either NADPH oxidases or peroxidases that may exist singly or in combination in different plant species have been proposed for the generation of ROS. We identified an Arabidopsis thaliana azide-sensitive but diphenylene iodonium-insensitive apoplastic oxidative burst that generates H2O2 in response to a Fusarium oxysporum cell-wall preparation. Transgenic Arabidopsis plants expressing an anti-sense cDNA encoding a type III peroxidase, French bean peroxidase type 1 (FBP1) exhibited an impaired oxidative burst and …

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Detection Of Proteins By Two-Photon Excitation Of Native Fluorescence, Li Li Aug 2006

Detection Of Proteins By Two-Photon Excitation Of Native Fluorescence, Li Li

Theses and Dissertations

Proteins are of primary importance to the structure and function of all living cells. Study of proteins relies on the ability to separate a complex mixture so that individual proteins can be more easily processed by other techniques. Since protein samples often exist at low concentration in a small volume, the trend in chemical analysis is toward micro total analysis systems (µTAS) or lab-on-a-chip devices. Among µTAS separation methods, the relatively new electric field gradient focusing (EFGF) technique has shown potential. It focuses and separates analytes based on their electrophoretic migration in an opposing hydrodynamic flow. The detection principles that …

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Perchlorate And Nitrate Remediation Efficiency And Microbial Diversity In A Containerized Wetland Bioreactor, Paula Krauter, Bill Daily Jr., Valerie Dibley, Holly Pinkart, Tina Legler Aug 2006

Perchlorate And Nitrate Remediation Efficiency And Microbial Diversity In A Containerized Wetland Bioreactor, Paula Krauter, Bill Daily Jr., Valerie Dibley, Holly Pinkart, Tina Legler

All Faculty Scholarship for the College of the Sciences

We have developed a method to remove perchlorate (14–27 μg/L) and nitrate (48 mg/L) from contaminated groundwater using a wetland bioreactor. The bioreactor has operated continuously in a remote field location for more than 2 yr with a stable ecosystem of indigenous organisms. This study assesses the bioreactor for long-term perchlorate and nitrate remediation by evaluating influent and effluent groundwater for oxidation-reduction conditions and nitrate and perchlorate concentrations. Total community DNA was extracted and purified from 10-g sediment samples retrieved from vertical coring of the bioreactor during winter. Analysis by denaturing gradient gel electrophoresis of short, 16S rDNA, polymerase-chain-reaction products …

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Selenium Metabolism In Trypanosoma: Characterization Of Selenoproteomes And Identification Of A Kinetoplastida-Specific Selenoprotein, Alexey V. Lobanov, Stephan Gromer, Gustavo Salinas, Vadim Gladyshev Aug 2006

Selenium Metabolism In Trypanosoma: Characterization Of Selenoproteomes And Identification Of A Kinetoplastida-Specific Selenoprotein, Alexey V. Lobanov, Stephan Gromer, Gustavo Salinas, Vadim Gladyshev

Vadim Gladyshev Publications

Proteins containing the 21st amino acid selenocysteine (Sec) are present in the three domains of life. However, within lower eukaryotes, particularly parasitic protists, the dependence on the trace element selenium is variable as many organisms lost the ability to utilize Sec. Herein, we analyzed the genomes of Trypanosoma and Leishmania for the presence of genes coding for Sec-containing proteins. The selenoproteomes of these flagellated protozoa have three selenoproteins, including distant homologs of mammalian SelK and SelT, and a novel multidomain selenoprotein designated SelTryp. In SelK and SelTryp, Sec is near the C-terminus, and in all three selenoproteins, it is within …

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Characterization Of Alternative Cytosolic Forms And Cellular Targets Of Mouse Mitochondrial Thioredoxin Reductase, Anton A. Turanov, Dan Su, Vadim N. Gladyshev Aug 2006

Characterization Of Alternative Cytosolic Forms And Cellular Targets Of Mouse Mitochondrial Thioredoxin Reductase, Anton A. Turanov, Dan Su, Vadim N. Gladyshev

Vadim Gladyshev Publications

Thioredoxin reductase (TR) and thioredoxin (Trx) define a major cellular redox system that maintains cysteine residues in numerous proteins in the reduced state. Both cytosolic (TR1 and Trx1) and mitochondrial (TR3 and Trx2) enzymes are essential in mammals, but the function of the mitochondrial system is less understood. In this study, we characterized subcellular localization of three TR3 forms that are generated by alternative first exon splicing and that differ in their N-terminal sequences. Only one of these forms resides in mitochondria, whereas the two other isoforms are cytosolic. Consistent with this finding, TR3 did not have catalytic preferences for …

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Supplementary Material For: Secis Elements In The Coding Regions Of Selenoprotein Transcripts Are Functional In Higher Eukaryotes, Heiko Mix, Alexey V. Lobanov, Vadim Gladyshev Aug 2006

Supplementary Material For: Secis Elements In The Coding Regions Of Selenoprotein Transcripts Are Functional In Higher Eukaryotes, Heiko Mix, Alexey V. Lobanov, Vadim Gladyshev

Vadim Gladyshev Publications

Figure S1. Nucleotide sequence alignment of GPx4 sequences.
For: M. musculus, H. sapiens, G. gallus, A. thaliana, Fowlpox virus, and Canarypox virus

Figure S2. Alignment of GPx4 SECIS elements.
For: H. sapiens, M. musculus, G. gallus, Fowlpox, Canarypox, and MCV

Supplementary Table S1. Viral genome sequences used in a computational analysis
From Abelson murine leukemia virus through Zygosaccharomyces bailii virus Z

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Agswe1p Regulates Mitosis In Response To Morphogenesis And Nutrients In Multinucleated Ashbya Gossypii Cells, Hanspeter Helfer, Amy S. Gladfelter Aug 2006

Agswe1p Regulates Mitosis In Response To Morphogenesis And Nutrients In Multinucleated Ashbya Gossypii Cells, Hanspeter Helfer, Amy S. Gladfelter

Dartmouth Scholarship

Nuclei in the filamentous, multinucleated fungus Ashbya gossypii divide asynchronously. We have investigated what internal and external signals spatially direct mitosis within these hyphal cells. Mitoses are most common near cortical septin rings found at growing tips and branchpoints. In septin mutants, mitoses are no longer concentrated at branchpoints, suggesting that the septin rings function to locally promote mitosis near new branches. Similarly, cells lacking AgSwe1p kinase (a Wee1 homologue), AgHsl1p (a Nim1-related kinase), and AgMih1p phosphatase (the Cdc25 homologue that likely counteracts AgSwe1p activity) also have mitoses distributed randomly in the hyphae as opposed to at branchpoints. Surprisingly, however, …

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Biophotonics: Electrochemiluminescence At Microelectrodes During Pcr Amplification Of Dna, Rosemary L. Smith, Scott Collins Aug 2006

Biophotonics: Electrochemiluminescence At Microelectrodes During Pcr Amplification Of Dna, Rosemary L. Smith, Scott Collins

University of Maine Office of Research Administration: Grant Reports

This project investigates a new technique for in situ quantification of Polymerase Chain Reaction (PCR) amplification products using electrochemiluminescence (ECL). The technique implements the highly sensitive, ECL detection and quantification of tris(2,2'bipyridyl) ruthenium (II) labeled DNA. This method is expected to yield significant improvement in speed, cost and performance over existing quantitative PCR methods, by reducing the number and quantity of reagents, reducing the number of sample preparation steps, increasing sensitivity, and shortening analysis time.

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Ferritin: Mechanistic Studies And Electron Transfer Properties, Bo Zhang Aug 2006

Ferritin: Mechanistic Studies And Electron Transfer Properties, Bo Zhang

Theses and Dissertations

Ferritins are ubiquitous iron storage proteins in living systems. Although much is known about the iron deposition process in ferritin and a mechanism has been developed, several important issues still remain unknown. One lingering question is the less than stoichiometric quantities of hydrogen peroxide detected in previous studies on animal ferritins. Extensive experimental data on identifying the species in competition for peroxide equivalents point to a surprising conclusion that H2O2 generated in the ferroxidase reaction is consumed by amine buffers that are commonly employed in in vitro ferritin studies, while non-nitrogen containing buffers, such as acetate, phosphate, and carbonate, do …

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Cell Edge Features Affected By Microtubule Inhibitor Combinations, Sonal Uppal, Nancy Boudreau, Elizabeth Wendt, Carol Heckman Aug 2006

Cell Edge Features Affected By Microtubule Inhibitor Combinations, Sonal Uppal, Nancy Boudreau, Elizabeth Wendt, Carol Heckman

Applied Statistics and Operations Research Faculty Publications

The tumor promoter, phorbol 12-myristate 13-acetate (PMA), enhances tumor yield through an epigenetic mechanism. PMA, like another promoter, phosphatase inhibitor okadaic acid, works by maintaining proteins in a phosphorylated state. In order to identify chemicals with promoter and antipromoter effects, this laboratory has developed a standard curve of morphogenetic changes using data from precancerous cell lines that eventually became neoplastic. Using the curve as a basis of comparison, we defined the “signature” phenotype as that adopted when a cell line became neoplastic. The results of solving for signature type disclosed that the microtubule-depolymerizing compound, colchicine, had a promoter-like effect [2]. …

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Semi-Global Analysis Of The Early Cold Stress Response Transcriptome Of Developing Seedlings Of Rice (Oryzasativa L.,Japonica), Chen Cheng Aug 2006

Semi-Global Analysis Of The Early Cold Stress Response Transcriptome Of Developing Seedlings Of Rice (Oryzasativa L.,Japonica), Chen Cheng

Electronic Theses and Dissertations

Plants are either sensitive or insensitive to low temperatures. Cool-season species acclimate to chilling and develop tolerance to freezing. Warm-season species vary in the degree of sensitivity to chilling and are not capable of acclimation. Both freezing and chilling tolerance involve the activity of an intricately coordinated network of genes. The regulatory network that defines cold acclimation and freezing tolerance is well understood in Arabidopsis. The centerpiece of this network is a group of transcriptional activators that coordinate a battery of downstream defense-related genes. In contrast, little is known about the corresponding regulon in non-acclimating species. This study utilized …

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Myod Synergizes With The E-Protein Heb Beta To Induce Myogenic Differentiation, Maura H. Parker, Robert L.S. Perry, Melanie C. Fauteux, Charlotte A. Berkes, Michael A. Rudnicki Aug 2006

Myod Synergizes With The E-Protein Heb Beta To Induce Myogenic Differentiation, Maura H. Parker, Robert L.S. Perry, Melanie C. Fauteux, Charlotte A. Berkes, Michael A. Rudnicki

Biology Faculty Publications

The MyoD family of basic helix-loop-helix transcription factors function as heterodimers with members of the E-protein family to induce myogenic gene activation. The E-protein HEB is alternatively spliced to generate alpha and beta isoforms. While the function of these molecules has been studied in other cell types, questions persist regarding the molecular functions of HEB proteins in skeletal muscle. Our data demonstrate that HEB alpha expression remains unchanged in both myoblasts and myotubes, whereas HEB beta is upregulated during the early phases of terminal differentiation. Upon induction of differentiation, a MyoD-HEB beta complex bound the E1 E-box of the myogenin …

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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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Structure-Activity Studies Of Glycosphingolipids As Antigens Of Natural Killer T Cells, Randal Donald Goff Jul 2006

Structure-Activity Studies Of Glycosphingolipids As Antigens Of Natural Killer T Cells, Randal Donald Goff

Theses and Dissertations

Glycosphingolipids (GSLs), composed of a polar saccharide head and a lipophilic ceramide tail, are ubiquitous components of the plasma membrane of eukaryotic cells. They serve in many regulatory capacities and have antigenic properties towards natural killer T (NKT) cells of the innate immune system. Critical to the recognition of glycosylceramides by NKT cells are antigen presenting cells (APC), such as dendritic cells, which are responsible for binding, processing, and delivery of ligands to these lymphocytes. This event is mediated by CD1d, a major histocompatibility complex-like protein expressed on the surface of APCs, which binds GSL antigens by the ceramide moiety …

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Accumulation Of Phycotoxins In The Mussel Mytilus Galloprovincialis From The Central Adriatic Sea, Maja Pavela-Vrančić, Ivana Ujević, Živana Ninčević Gladan, Ambrose Furey Jul 2006

Accumulation Of Phycotoxins In The Mussel Mytilus Galloprovincialis From The Central Adriatic Sea, Maja Pavela-Vrančić, Ivana Ujević, Živana Ninčević Gladan, Ambrose Furey

Physical Sciences Publications

Surveys of DSP (Diarrheic Shellfish Poisoning) toxin profiles in the mussel Mytilus galloprovincialis from coastal waters of the central Adriatic Sea, over the years 1995 to 2001, demonstrate that incidents of shellfish toxicity in this area are dominated by the occurrence of okadaic acid (OA) and a PTX derivative, 7-epi-pectenotoxin-2-seco acid (7-epi-PTX-2SA). Toxin composition and the relative ratio of toxic components in shellfish is in correlation with the occurrence of DSP producing organisms from the Dinophysis species along with Prorocentrum micans and Lingulodinium polyedrum. The occurrence of D. sacculus shortly before the appearance of OA in shellfish implicates its possible …

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The Effect Of Protein Dielectric Coefficient On The Ionic Selectivity Of A Calcium Channel, Douglas Henderson, Dezso Boda, Monika Valisko, Bob Eisenberg, Wolfgang Nonner, Dirk Gillespie Jul 2006

The Effect Of Protein Dielectric Coefficient On The Ionic Selectivity Of A Calcium Channel, Douglas Henderson, Dezso Boda, Monika Valisko, Bob Eisenberg, Wolfgang Nonner, Dirk Gillespie

Faculty Publications

Calcium-selective ion channels are known to have carboxylate-rich selectivity filters, a common motif that is primarily responsible for their high Ca2+ affinity. Different Ca2+ affinities ranging from micromolar (the L-type Ca channel) to millimolar (the ryanodine receptor channel) are closely related to the different physiological functions of these channels. To understand the physical mechanism for this range of affinities given similar amino acids in their selectivity filters, we use grand canonical Monte Carlo simulations to assess the binding of monovalent and divalent ions in the selectivity filter of a model Ca channel. We use a reduced model where the electrolyte …

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Dna-Templated Surface Alignment And Characterization Of Carbon Nanotubes., Huijun Xin Jul 2006

Dna-Templated Surface Alignment And Characterization Of Carbon Nanotubes., Huijun Xin

Theses and Dissertations

Carbon nanotubes are appealing materials for nanofabrication due to their unique properties and structures. However, for carbon nanotubes to be used in mass-fabricated devices, precise control of nanotube orientation and location on surfaces is critical. I have developed a technique to align single-walled carbon nanotubes (SWNTs) on surfaces from a droplet of nanotube suspension under gas flow. Fluid motion studies indicate that alignment is likely due to circulation of SWNTs in the droplet. My work provides a facile method for generating oriented nanotubes for nanodevice applications. I have also devised an approach for localizing SWNTs onto 1-pyrenemethylamine-decorated DNA on surfaces. …

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Development Of An In Vitro Protocol To Study The Effect Of Estrogen On Osteoblast Activity, Sourik Ganguly Jul 2006

Development Of An In Vitro Protocol To Study The Effect Of Estrogen On Osteoblast Activity, Sourik Ganguly

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science & Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Sourik Ganguly on July 7, 2006.

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Enhanced Electrospray Ionization For Mass Spectrometry And Ion Mobility Spectrometry, Li Zhou Jul 2006

Enhanced Electrospray Ionization For Mass Spectrometry And Ion Mobility Spectrometry, Li Zhou

Theses and Dissertations

Electrospray ionization (ESI) has become one of the most commonly used ionization techniques for mass spectrometry (MS) and ion mobility spectrometry (IMS), and efforts continue to improve its performance. ESI-MS is most recognized for its wide application to biomacromolecules where high sensitivity is of paramount importance. However, the major limitation in sensitivity with ESI-MS is due to its low ion transmission efficiency from the ESI source into the sampling orifice and through any stages utilized for transfer of ions from atmosphere to vacuum in the MS. A series of atmospheric pressure ion focusing interfaces were designed and implemented to enhance …

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Electric Field Gradient Focusing-Uv Detection For Protein Analysis, Shu-Ling Lin Jul 2006

Electric Field Gradient Focusing-Uv Detection For Protein Analysis, Shu-Ling Lin

Theses and Dissertations

Electric field gradient focusing (EFGF) utilizes a hydrodynamic flow and an electric field gradient to focus and concentrate charged analytes and order them in a separation channel according to electrophoretic mobility. Elution can be achieved by decreasing the applied voltage or increasing the hydrodynamic flow. EFGF has the advantages of concentrating a large volume (100 micro-L) of target proteins without significant band broadening and simultaneously removing unwanted components from the sample. Two types of EFGF devices have been investigated to concentrate and separate proteins: a fiber-based EFGF device and a hydrogel-based EFGF device. Using fiber-based EFGF with UV detection, a …

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Concurrent Expression Of Hyaluronan Biosynthetic And Processing Enzymes Promotes Growth And Vascularization Of Prostate Tumors In Mice, Melanie A. Simpson Jul 2006

Concurrent Expression Of Hyaluronan Biosynthetic And Processing Enzymes Promotes Growth And Vascularization Of Prostate Tumors In Mice, Melanie A. Simpson

Department of Biochemistry: Faculty Publications

Aggressive cells in prostate cancer secrete extracellular hyaluronan (HA) as a result of up-regulated HA synthase enzymes HAS2 and HAS3. Combined detection of HA and the HA processing hyaluronidase enzyme Hyal1 in prostate tumors correlates with poor outcome. HA oligomers produced by hyaluronidases are potent angiogenic stimuli. We investigated the respective roles of HAS2 and Hyal1 using 22Rv1 human prostate tumor cells that lack both enzyme activities. Stable transfectants were selected for overexpression of Hyal1 or HAS2 and for coexpression of Hyal1 and HAS2. HAS2 overexpression elevated HA production and excess pericellular HA retention. However, HAS2-transfected tumor cell growth in …

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A Comprehensive Structure–Function Analysis Of Arabidopsis Sni1 Defines Essential Regions And Transcriptional Repressor Activity, Rebecca A. Mosher, Wendy E. Durrant, Dong Wang, Jungi Song, Xinnian Dong Jul 2006

A Comprehensive Structure–Function Analysis Of Arabidopsis Sni1 Defines Essential Regions And Transcriptional Repressor Activity, Rebecca A. Mosher, Wendy E. Durrant, Dong Wang, Jungi Song, Xinnian Dong

Dong Wang

The expression of systemic acquired resistance (SAR) in plants involves the upregulation of many Pathogenesis-Related (PR) genes, which work in concert to confer resistance to a broad spectrum of pathogens. Because SAR is a costly process, SAR-associated transcription must be tightly regulated. Arabidopsis thaliana SNI1 (for Suppressor of NPR1, Inducible) is a negative regulator of SAR required to dampen the basal expression of PR genes. Whole genome transcriptional profiling showed that in the sni1 mutant, Nonexpresser of PR genes (NPR1)–dependent benzothiadiazole S-methylester–responsive genes were specifically derepressed. Interestingly, SNI1 also repressed transcription when expressed in yeast, suggesting that it functions as …

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Visualization Of Intracellular Transport Of Vesicular Stomatitis Virus Nucleocapsids In Living Cells, Subash C. Das, Debasis Nayak, You Zhou, Asit K. Pattnaik Jul 2006

Visualization Of Intracellular Transport Of Vesicular Stomatitis Virus Nucleocapsids In Living Cells, Subash C. Das, Debasis Nayak, You Zhou, Asit K. Pattnaik

School of Veterinary and Biomedical Sciences: Faculty Publications

The phosphoprotein (P) of vesicular stomatitis virus (VSV) is a subunit of the viral RNA polymerase. In previous studies, we demonstrated that insertion of 19 amino acids in the hinge region of the protein had no significant effect on P protein function. In the present study, we inserted full-length enhanced green fluorescent protein (eGFP) in frame into the hinge region of P and show that the fusion protein (PeGFP) is functional in viral genome transcription and replication, albeit with reduced activity. A recombinant vesicular stomatitis virus encoding PeGFP in place of the P protein (VSV-PeGFP), which possessed reduced growth kinetics …

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Is There A Twenty Third Amino Acid In The Genetic Code?, Alexey V. Lobanov, Gregory V. Kryukov, Dolph L. Hatfield, Vadim Gladyshev Jul 2006

Is There A Twenty Third Amino Acid In The Genetic Code?, Alexey V. Lobanov, Gregory V. Kryukov, Dolph L. Hatfield, Vadim Gladyshev

Vadim Gladyshev Publications

The universal genetic code includes 20 common amino acids. In addition, selenocysteine (Sec) and pyrrolysine (Pyl), known as the twenty first and twenty second amino acids, are encoded by UGA and UAG, respectively, which are the codons that usually function as stop signals. The discovery of Sec and Pyl suggested that the genetic code could be further expanded by reprogramming stop codons. To search for the putative twenty third amino acid, we employed various tRNA identification programs that scanned 16 archaeal and 130 bacterial genomes for tRNAs with anticodons corresponding to the three stop signals. Our data suggest that the …

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