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2010

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Articles 1 - 30 of 531

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Enhancement Of Reactive Oxygen Species Production And Chlamydial Infection By The Mitochondrial Nod-Like Family Member Nlrx1, Ali A. Abdul-Sater, Najwene Saïd-Sadier, Verissa M. Lam, Bhavni Singh, Matthew A. Pettengill, Fraser Soares, Ivan Tattoli, Simone Lipinski, Stephen E. Girardin, Philip Rosenstiel, David M. Ojcius Dec 2010

Enhancement Of Reactive Oxygen Species Production And Chlamydial Infection By The Mitochondrial Nod-Like Family Member Nlrx1, Ali A. Abdul-Sater, Najwene Saïd-Sadier, Verissa M. Lam, Bhavni Singh, Matthew A. Pettengill, Fraser Soares, Ivan Tattoli, Simone Lipinski, Stephen E. Girardin, Philip Rosenstiel, David M. Ojcius

Dugoni School of Dentistry Faculty Articles

Chlamydia trachomatis infections cause severe and irreversible damage that can lead to infertility and blindness in both males and females. Following infection of epithelial cells, Chlamydia induces production of reactive oxygen species (ROS). Unconventionally, Chlamydiae use ROS to their advantage by activating caspase-1, which contributes to chlamydial growth. NLRX1, a member of the Nod-like receptor family that translocates to the mitochondria, can augment ROS production from the mitochondria following Shigella flexneri infections. However, in general, ROS can also be produced by membrane-bound NADPH oxidases. Given the importance of ROS-induced caspase-1 activation in growth of the chlamydial vacuole, we investigated the ...


Characterization Of The Role Of Nicotine And Delta 9-Thc In Modulation Of Neuroinflammation, Jared Ehrhart Dec 2010

Characterization Of The Role Of Nicotine And Delta 9-Thc In Modulation Of Neuroinflammation, Jared Ehrhart

Graduate Theses and Dissertations

Neuroinflammation is a major driving force in the progression of neurodegenerative disorders. Nicotinic acetylcholine receptors, as well as cannabinoid CB2 receptors, have been shown to have strong anti-inflammatory properties when activated. These effects are shown, in vivo, to be a result of stimulation of α7 nAChRs and CB2 cannabinoid receptors. Microglia cells, an immune cell in the brain, are shown to express both of these receptor subtypes. The studies detailed herein, investigated the ability of two compounds, nicotine and Δ9-THC, in modulation of inflammatory processes. Stimulation of these receptors on microglia using nicotine and Δ9-THC blocked the activation of these ...


Strategies To Resolve The Three-Dimensional Structure Of The Genome Of Small Single-Stranded Icosahedral Viruses, Eduardo Sanz Garcia Dec 2010

Strategies To Resolve The Three-Dimensional Structure Of The Genome Of Small Single-Stranded Icosahedral Viruses, Eduardo Sanz Garcia

Theses and Dissertations

The aim of this study is the three-dimensional structural characterization of the genome packaging inside viral capsids via cryo-electron microscopy and three-dimensional reconstruction. The genome of some single-stranded viruses can be densely packaged within their capsid shells. Several stretches of the genome are known to adopt stable secondary structures, however, to date, little is known about the three-dimensional organization of the genome inside their capsid shells. Two techniques have been developed to facilitate the structural elucidation of genome packaging: the asymmetric random-model method, and the symmetry-mismatch, random model method. Both techniques were successfully tested with model and experimental data. The ...


Structure-Based Design Of Inhibitors Targeting Influenza A Virus M2 Proton Channel (A/M2), Jun Wang Dec 2010

Structure-Based Design Of Inhibitors Targeting Influenza A Virus M2 Proton Channel (A/M2), Jun Wang

Publicly Accessible Penn Dissertations

Influenza A virus M2 (A/M2) forms a homotetrameric channel in viral membranes that is highly selective for protons. A/M2 has been extensively studied by electrophysiologists, biophysicists, structural biologists and biochemists in order to understand the mechanism and selectivity of proton conductance from the structural basis. Medicinal chemists have also studied A/M2 as therapeutic target for anti-flu drugs. However, research on A/M2 drug binding lead to entirely different binding sites of two very similar anti-flu drugs. In light of the urgency in developing novel antivirals against drug resistant A/M2 mutants, it is imperative to solve this ...


Nucleoside Modifications Suppress Rna Activation Of Cytoplasmic Rna Sensors, Bart R. Anderson Dec 2010

Nucleoside Modifications Suppress Rna Activation Of Cytoplasmic Rna Sensors, Bart R. Anderson

Publicly Accessible Penn Dissertations

Multiple innate defense pathways exist to recognize and defend against foreign nucleic acids. Unlike innate immune receptors that recognize structures specific for pathogens that are not shared by mammalian hosts — for example, toll-like receptor (TLR)4-lipopolysaccharide, TLR5-flagellin, NOD1 and 2-peptidoglycan — all nucleic acids are made from four components that are identical from bacteria to man. Nucleoside modifications are prevalent in nature but vary greatly in their distribution and frequency, and therefore could serve as patterns for recognition of pathogenic nucleic acids. The presence of modified nucleosides in RNA reduces the activation of RNA-sensing TLRs and retinoic acid inducible gene I ...


The Tumor Suppressor Protein P53 And The Antagonizing Oncoprotein E6 From Human Papillomavirus Type 16, Kimberly A. Malecka Dec 2010

The Tumor Suppressor Protein P53 And The Antagonizing Oncoprotein E6 From Human Papillomavirus Type 16, Kimberly A. Malecka

Publicly Accessible Penn Dissertations

The tumor suppressor protein p53 transactivates genes involved in cell cycle arrest and apoptosis in response to DNA damage, cellular stress and some oncogenic proteins. The wild type polypeptide chain of p53 has four distinct domains, including the sequence specific DNA binding core domain and the C terminal tetramerization domain. p53 must retain its ability to oligomerize and bind DNA targets in vivo to fulfill its function. Using X-ray crystallography and a crosslinking strategy, the structure of a wild type tetrameric p53 core domain bound to its consensus sequence was solved. This structure gives insight into DNA bend, core domain-DNA ...


A Study Of Molecular Adsorption And Transport At Cell Membrane And Biologically Relevant Surfaces By Second Harmonic Generation, Jia Zeng Dec 2010

A Study Of Molecular Adsorption And Transport At Cell Membrane And Biologically Relevant Surfaces By Second Harmonic Generation, Jia Zeng

Publicly Accessible Penn Dissertations

Most of the biological processes in living systems involve molecular adsorption and transport at biomembranes. It is highly desired to study the time-resolved transport kinetics through living cell membranes. In this thesis, an experimental means based on a nonlinear optical phenomenon, Second Harmonic Generation (SHG) has been demonstrated to detect the molecular adsorption and transport through living cell membranes in real time and to evaluate the salt ion effects on adsorption processes in biologically relevant colloidal systems. In the case of gram-negative bacteria, E.coli, a hydrophobic cation, Malachite Green (MG) has been observed to adsorb onto the cell surface ...


Characterization Of Thap10 And Thap11 As Transcriptional Repressors In Dna Damage And Colon Cancer Progression, James B. Parker Dec 2010

Characterization Of Thap10 And Thap11 As Transcriptional Repressors In Dna Damage And Colon Cancer Progression, James B. Parker

Publicly Accessible Penn Dissertations

The THAP (Thanatos associated protein) domain is an evolutionarily conserved zinc-finger motif highly similar to the sequence specific DNA binding domain of Drosophila P element transposase. Emerging data suggest THAP proteins may function in DNA and chromatin dependent processes, including transcription. However, the transcriptional regulatory function, mechanisms of action, and role of most THAP proteins in normal and aberrant cellular processes remain largely unknown.

In this thesis, we demonstrate that several human THAP proteins contain transcriptional repressor activity and specifically identify THAP10 and THAP11 as differentially expressed in human DNA damage and colon cancer progression, respectively. THAP10 and THAP11 repressed ...


Utilizing Genetically Engineered Mouse Models Of Pancreatic Cancer: Evaluating The Role Of Cathepsin B And The Efficacy Of Farnesyl Thiosalicylic Acid, Aarthi Gopinathan Dec 2010

Utilizing Genetically Engineered Mouse Models Of Pancreatic Cancer: Evaluating The Role Of Cathepsin B And The Efficacy Of Farnesyl Thiosalicylic Acid, Aarthi Gopinathan

Publicly Accessible Penn Dissertations

I have utilized genetically engineered mouse models of pancreatic cancer to identify a potential new therapeutic target, and to test the efficacy of a putative ras inhibitor. In the first part, I show that cathepsin B is upregulated during disease progression in the mouse pancreas, as is overall cathepsin activity. Loss of cathepsin B decreases preinvasive disease burden and imparts a significant survival benefit, with a consistent decrease in proliferation. In addition, lack of cathepsin B also decreases the burden of liver metastasis. Phospho-Erk localization appears to be affected by cathepsin B loss, which may account for the defect in ...


Ku Can Contribute To Telomere Lengthening In Yeast At Multiple Positions In The Telomerase Rnp, David C. Zappulla, Karen J. Goodrich, Julian R. Arthur, Lisa A. Gurski, Elizabeth M. Denham, Anne E. Stellwagen, Thomas R. Cech Dec 2010

Ku Can Contribute To Telomere Lengthening In Yeast At Multiple Positions In The Telomerase Rnp, David C. Zappulla, Karen J. Goodrich, Julian R. Arthur, Lisa A. Gurski, Elizabeth M. Denham, Anne E. Stellwagen, Thomas R. Cech

Chemistry & Biochemistry Faculty Contributions (1986-2018)

Unlike ribonucleoprotein complexes that have a highly ordered overall architecture, such as the ribosome, yeast telomerase appears to be much more loosely constrained. Here, we investigate the importance of positioning of the Ku subunit within the 1157-nt yeast telomerase RNA (TLC1). Deletion of the 48-nt Ku-binding hairpin in TLC1 RNA (tlc1Δ48) reduces telomere length, survival of cells with gross chromosomal rearrangements, and de novo telomere addition at a broken chromosome end. To test the function of Ku at novel positions in the telomerase RNP, we reintroduced its binding site into tlc1Δ48 RNA at position 446 or 1029. We found that ...


Distinct Functions For The Drosophila Pirna Pathway In Genome Maintenance And Telomere Protection, Jaspreet S. Khurana, Jia Xu, Zhiping Weng, William E. Theurkauf Dec 2010

Distinct Functions For The Drosophila Pirna Pathway In Genome Maintenance And Telomere Protection, Jaspreet S. Khurana, Jia Xu, Zhiping Weng, William E. Theurkauf

Open Access Articles

Transposons and other selfish DNA elements can be found in all phyla, and mobilization of these elements can compromise genome integrity. The piRNA (PIWI-interacting RNA) pathway silences transposons in the germline, but it is unclear if this pathway has additional functions during development. Here we show that mutations in the Drosophila piRNA pathway genes, armi, aub, ago3, and rhi, lead to extensive fragmentation of the zygotic genome during the cleavage stage of embryonic divisions. Additionally, aub and armi show defects in telomere resolution during meiosis and the cleavage divisions; and mutations in lig-IV, which disrupt non-homologous end joining, suppress these ...


Isolation Of Class Ii Shsp 17.0 From Zea Maize For Future Studies In Chaperone Activity And Subunit Exchange, Michele Schleich, Hannah Tims Dec 2010

Isolation Of Class Ii Shsp 17.0 From Zea Maize For Future Studies In Chaperone Activity And Subunit Exchange, Michele Schleich, Hannah Tims

Honors Projects and Presentations: Undergraduate

Small heat shock proteins (sHsps) are ubiquitous proteins that act as molecular chaperones under heat stress in a vast range of organisms. These proteins bind and hold in a stable conformation partially unfolded or heat-denatured intracellular proteins. Under non-stressful conditions, sHsps can be found in oligomeric assemblies with the oligomers acting as storage units for dimers and monomers. As temperatures increase to stressful levels, these oligomers dissociate into suboligomeric species, the dimer being the preferred species, to permit binding of substrate. Following substrate binding, oligomeric species may reform, and contain a variable number of sHsp:substrate complexes depending on the ...


Chemical Vapor Deposition Of Silanes And Patterning On Silicon, Feng Zhang Dec 2010

Chemical Vapor Deposition Of Silanes And Patterning On Silicon, Feng Zhang

Theses and Dissertations

Self assembled monolayers (SAMs) are widely used for surface modification. Alkylsilane monolayers are one of the most widely deposited and studied SAMs. My work focuses on the preparation, patterning, and application of alkysilane monolayers. 3-aminopropyltriethoxysilane (APTES) is one of the most popular silanes used to make active surfaces for surface modification. To possibly improve the surface physical properties and increase options for processing this material, I prepared and studied a series of amino silane surfaces on silicon/silicon dioxide from APTES and two other related silanes by chemical vapor deposition (CVD). I also explored CVD of 3-mercaptopropyltrimethoxysilane on silicon and ...


The Role Of The Mcm2 Subunit In Regulating The Activities Of The Mcm2-7 Helicase, Brent E. Stead Dec 2010

The Role Of The Mcm2 Subunit In Regulating The Activities Of The Mcm2-7 Helicase, Brent E. Stead

Electronic Thesis and Dissertation Repository

The transmission of genetic information from parental to daughter cells requires the faithful duplication of an organism’s genome. Uncontrolled DNA replication can result in proliferative diseases, such as cancer. DNA replication requires a single-stranded DNA template to be produced from duplex DNA. In eukaryotes, DNA unwinding for replication is performed by the heterohexameric replicative helicase complex comprised of the minichromosome maintenance proteins 2 through 7.

Each of the Mcm2-7 subunits likely has a unique role in DNA binding and unwinding by the Mcm2-7 complex. The present study examines the role of the Saccharomyces cerevisiae Mcm2 subunit in regulating the ...


Identification Of Regions Responsible For The Open Conformation Of S100a10 Using Chimaeric S100a11/S100a10 Proteins, Liliana Santamaria-Kisiel Dec 2010

Identification Of Regions Responsible For The Open Conformation Of S100a10 Using Chimaeric S100a11/S100a10 Proteins, Liliana Santamaria-Kisiel

Electronic Thesis and Dissertation Repository

S100A11 is a dimeric, EF-hand calcium-binding protein. Calcium binding to S100A11 results in a large conformational change that uncovers a broad hydrophobic surface used to interact with phospholipid-binding proteins (annexins A1 and A2), and facilitate membrane vesiculation events. In contrast to other S100 proteins, S100A10 is unable to bind calcium due to deletion and substitution of calcium-ligating residues. Despite this, calcium-free S100A10 assumes an “open” conformation that is very similar to S100A11 in its calcium-bound state (Ca2+-S100A11). To understand how S100A10 is able to adopt an open conformation in the absence of calcium, seven chimeric proteins were constructed where ...


10th Annual Senior Research Symposium Of The Department Of Biological Sciences, Chemistry And Biochemistry, Messiah College Dec 2010

10th Annual Senior Research Symposium Of The Department Of Biological Sciences, Chemistry And Biochemistry, Messiah College

School of Science, Engineering & Health (SEH) Symposium

No abstract provided.


Structural Insights Into Dna Replication And Lesion Bypass By Y Family Dna Polymerases, Kevin N. Kirouac Dec 2010

Structural Insights Into Dna Replication And Lesion Bypass By Y Family Dna Polymerases, Kevin N. Kirouac

Electronic Thesis and Dissertation Repository

Y family DNA polymerases are specialized enzymes for replication through sites of DNA damage in the genome. Although the DNA damage bypass activity of these enzymes is important for genome maintenance and integrity, it is also responsible for DNA mutagenesis due to the error-prone nature of the Y family. Understanding how these enzymes select incoming nucleotides during DNA replication will give insight into their role in cancer formation, aging, and evolution. This work attempts to mechanistically explain, primarily through X-ray crystallography and enzymatic activity assays, how Y family polymerases select incoming nucleotides in various DNA replication contexts. Initially, we sought ...


Drug Resistance Against Hcv Ns3/4a Inhibitors Is Defined By The Balance Of Substrate Recognition Versus Inhibitor Binding, Keith P. Romano, Akbar Ali, William E. Royer, Celia A. Schiffer Dec 2010

Drug Resistance Against Hcv Ns3/4a Inhibitors Is Defined By The Balance Of Substrate Recognition Versus Inhibitor Binding, Keith P. Romano, Akbar Ali, William E. Royer, Celia A. Schiffer

Biochemistry and Molecular Pharmacology Publications and Presentations

Hepatitis C virus infects an estimated 180 million people worldwide, prompting enormous efforts to develop inhibitors targeting the essential NS3/4A protease. Resistance against the most promising protease inhibitors, telaprevir, boceprevir, and ITMN-191, has emerged in clinical trials. In this study, crystal structures of the NS3/4A protease domain reveal that viral substrates bind to the protease active site in a conserved manner defining a consensus volume, or substrate envelope. Mutations that confer the most severe resistance in the clinic occur where the inhibitors protrude from the substrate envelope, as these changes selectively weaken inhibitor binding without compromising the binding ...


Dual Inhibition Of Sodium-Mediated Proton And Calcium Efflux Triggers Non-Apoptotic Cell Death In Malignant Gliomas, William Harley, Candace Floyd, Tamara Dunn, Xiao-Dong Zhang, Tsung-Yu Chen, Manu Hegde, Hasan Palandoken, Michael H. Nantz, Leonardo Leon, K.L. Carraway Iii, Bruce Lyeth, Fredric A. Gorin Dec 2010

Dual Inhibition Of Sodium-Mediated Proton And Calcium Efflux Triggers Non-Apoptotic Cell Death In Malignant Gliomas, William Harley, Candace Floyd, Tamara Dunn, Xiao-Dong Zhang, Tsung-Yu Chen, Manu Hegde, Hasan Palandoken, Michael H. Nantz, Leonardo Leon, K.L. Carraway Iii, Bruce Lyeth, Fredric A. Gorin

Chemistry and Biochemistry

Malignant glioma cells maintain an elevated intracellular pH (pHi) within hypoxic–ischemic tumormicroenvironments through persistent activation of sodium–proton transport (McLean et al., 2000). Amiloride has been reported to selectively kill human malignant glioma cell lines but not primary astrocytes (Hegde et al., 2004). While amiloride reduces pHi of malignant gliomas by inhibiting isoform 1 of sodium–proton exchange (NHE1), direct acidification was shown to be cytostatic rather than cytotoxic. At cytotoxic concentrations, amiloride has multiple drug targets including inhibition of NHE1 and sodium–calciumexchange. Amiloride's glioma cytotoxicity can be explained, at least in part, by dual ...


Measurements Of Gas‐Phase Inorganic And Organic Acids From Biomass Fires By Negative‐Ion Proton‐Transfer Chemical‐Ionization Mass Spectrometry, P. Veres, James M. Roberts, I. R. Burling, C. Warneke, Joost De Gouw, Robert J. Yokelson Dec 2010

Measurements Of Gas‐Phase Inorganic And Organic Acids From Biomass Fires By Negative‐Ion Proton‐Transfer Chemical‐Ionization Mass Spectrometry, P. Veres, James M. Roberts, I. R. Burling, C. Warneke, Joost De Gouw, Robert J. Yokelson

Chemistry and Biochemistry Faculty Publications

[1] Emissions from 34 laboratory biomass fires were investigated at the combustion facility of the U.S. Department of Agriculture Fire Sciences Laboratory in Missoula, Montana. Gas-phase organic and inorganic acids were quantified using negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS), open-path Fourier transform infrared spectroscopy (OP-FTIR), and proton-transfer-reaction mass spectrometry (PTR-MS). NI-PT-CIMS is a novel technique that measures the mass-to-charge ratio (m/z) of ions generated from reactions of acetate (CH3C(O)O) ions with inorganic and organic acids. The emission ratios for various important reactive acids with respect to CO were determined. Emission ratios for isocyanic acid ...


Nicholas Reactions In The Construction Of Cyclohepta[De]Naphthalenes And Cyclohepta[De]Naphthalenones. The Total Synthesis Of Microstegiol, Rafiq Taj, James R. Green Dec 2010

Nicholas Reactions In The Construction Of Cyclohepta[De]Naphthalenes And Cyclohepta[De]Naphthalenones. The Total Synthesis Of Microstegiol, Rafiq Taj, James R. Green

Chemistry and Biochemistry Publications

The application of the Nicholas reaction chemistry of 2,7-dioxygenated naphthalenes in the synthesis of cyclohepta[de]napthalenes and in the synthesis of (±)-microstegiol (1) is presented. The substitution profile of Nicholas monosubstitution (predominantly C-1) and disubstitution reactions (predominantly 1,6-) on 2,7-dioxygenated napthalenes is reported. Application of a 1,8-dicondensation product and selected C-1 monocondensation products to the construction of cyclohepta[de]naphthalenes by way of ring closing metathesis and intramolecular Friedel−Crafts reactions, respectively, is described. Deprotection of the C-7 oxygen function to the corresponding naphthol allows tautomerization to cyclohepta[de]naphthalene-1-ones upon seven-membered-ring closure in most ...


Intramolecular Nicholas Reactions In The Synthesis Of Dibenzocycloheptanes. Synthesis Of Allocolchicine Nsc 51046 And Analogues And The Formal Synthesis Of (−)-Allocolchicine, Sinisa Djurdjevic, Fei Yang, James R. Green Dec 2010

Intramolecular Nicholas Reactions In The Synthesis Of Dibenzocycloheptanes. Synthesis Of Allocolchicine Nsc 51046 And Analogues And The Formal Synthesis Of (−)-Allocolchicine, Sinisa Djurdjevic, Fei Yang, James R. Green

Chemistry and Biochemistry Publications

The preparation of dibenzocycloheptyne-Co2(CO)6 complexes by intramolecular Nicholas reactions of biaryl-2-propargyl alcohol-Co2(CO)6 derivatives is described. Reductive decomplexation of the dibenzocycloheptyne-Co2(CO)6 complexes affords the corresponding dibenzocycloheptenes, individual members of which have been employed in a formal total synthesis of (−)-allocolchicine, the preparation of 6,7-dihydro-3,4,9,10,11-pentamethoxy-5H-dibenzo[a,c]cyclohepten-5-one, and the enantioselective total syntheses of NSC 51046 and its 3,8,9,10-tetramethoxy regioisomer.


The In Situ Function Of A Microbial Community Profiled By Ft-Ir: A Snapshot In Time, Ryan Roberts Dec 2010

The In Situ Function Of A Microbial Community Profiled By Ft-Ir: A Snapshot In Time, Ryan Roberts

Theses and Dissertations in Biochemistry

Photographs of an ecosystem are an important tool in macro-community ecology. The photograph is a permanent record of species phenotype. In microbiology, biochemical activity provides the most descriptive information of an organism’s phenotype. A method for fingerprinting all biochemical activities occurring within a microbial community is analogous to a photograph. Infrared spectroscopy in the region between wavelengths 2500 to 20,000 nm (mid-IR) is a well established instrumental method for fingerprinting the total biochemical profile of axenic cultures. Spectra are complex and sensitive as demonstrated by the ability to discriminate between strains of bacteria, fungi, and algae. This thesis ...


The Role Of The Suppressor Of Hairy-Wing Insulator Protein In Chromatin Organization And Expression Of Transposable Elements In Drosophila Melanogaster, Heather Anne Wallace Dec 2010

The Role Of The Suppressor Of Hairy-Wing Insulator Protein In Chromatin Organization And Expression Of Transposable Elements In Drosophila Melanogaster, Heather Anne Wallace

Doctoral Dissertations

ABSTRACT Chromatin insulators are required for proper temporal and spatial expression of genes in metazoans. Insulators are thought to play an important role in the regulation of gene expression through the formation of higher-order chromatin structures. One of the best characterized insulators is the Drosophila gypsy insulator, which is located in the gypsy retrovirus. Several proteins are required for gypsy insulator function, including Su(Hw), Mod(mdg4), and CP190. In addition to the gypsy insulator, these proteins are located throughout the genome at sites which are thought to correspond to endogenous insulators. Analysis of the distribution of insulator proteins across ...


Applications Of Site-Specific Recombination Systems In Transgene Expression And Marker Gene Removal, Mehmet Aydin Akbudak Dec 2010

Applications Of Site-Specific Recombination Systems In Transgene Expression And Marker Gene Removal, Mehmet Aydin Akbudak

Theses and Dissertations

Site Specific Recombination systems, such as FLP-FRT and Cre-lox, have been successfully used for site-specific gene integration and marker-gene deletion in plant systems. They are very useful tools in the integration of single-copy full-length transgene cassettes into the genome because the transgene integration via conventional methods often generate multi-copy locus. Such complex locus containing direct and inverted repeats of full-length and truncated copies of the transgene cassette generate aberrant RNA resulting in gene silencing. Therefore, for stable gene expression, a single copy transgene locus is preferred. However, even single copy locus sometimes succumbs to gene silencing. Although the mechanism is ...


Novel Constitutively Active Point Mutations In The Nh2 Domain Of Cxcr2 Capture The Receptor In Different Activation States, Giljun Park Dec 2010

Novel Constitutively Active Point Mutations In The Nh2 Domain Of Cxcr2 Capture The Receptor In Different Activation States, Giljun Park

Doctoral Dissertations

Chemokines are structurally and functionally related 8-10 kDa proteins defined by four conserved cysteine residues. They consist of a superfamily of proinflammatory mediators that promote the recruitment of various kinds of leukocytes and other cell types through binding to their respective chemokine receptor, a member of the GPCR family. Abnormal control of this system results in various diseases including tumorigenesis and cancer metastasis. Deregulation can occur when constitutively active mutant (CAM) chemokine receptors are locked in the “on” position. This can lead to cellular transformation/tumorigenesis. A viral CAM receptor, ORF74, that can cause tumors in humans, also has homology ...


Lateral Blood Flow Velocity Estimation Based On Ultrasound Speckle Size Change With Scan Velocity, Tiantian Xu, Gregory R. Bashford Dec 2010

Lateral Blood Flow Velocity Estimation Based On Ultrasound Speckle Size Change With Scan Velocity, Tiantian Xu, Gregory R. Bashford

Biomedical Imaging and Biosignal Analysis Laboratory

Conventional (Doppler-based) blood flow velocity measurement methods using ultrasound are capable of resolving the axial component (i.e., that aligned with the ultrasound propagation direction) of the blood flow velocity vector. However, these methods are incapable of detecting blood flow in the direction normal to the ultrasound beam. In addition, these methods require repeated pulse-echo interrogation at the same spatial location. A new method has been introduced which estimates the lateral component of blood flow within a single image frame using the observation that the speckle pattern corresponding to blood reflectors (typically red blood cells) stretches (i.e., is smeared ...


Genotype And Breed Trend Influences On Citric Acid And Coagulation Times Of Raw Milk, Melissa Looney Dec 2010

Genotype And Breed Trend Influences On Citric Acid And Coagulation Times Of Raw Milk, Melissa Looney

Dairy Science

The objective of the study was to determine if citric acid levels measured in milk was related to genetic variants identified in Holstein and Jersey cows. The data used were milk samples collected from both Holstein and Jersey cows at Cal Poly, San Luis Obispo. Citric acid levels and other constituents were measured using FTIR methods with the FOSS MilkoscanTM FT2 on each sample. Genotypes were obtained for the DGAT 1 locus using polymerase chain reaction and an enzymatic digestion using the MWO I restriction enzyme. Observations were obtained on 13 Holsteins and 12 Jersey cows. Results indicated that citric ...


Manganese Superoxide Dismutase (Mnsod) 3'-Untranslated Region: A Novel Molecular Sensor For Environmental Stress, Leena Chaudhuri Dec 2010

Manganese Superoxide Dismutase (Mnsod) 3'-Untranslated Region: A Novel Molecular Sensor For Environmental Stress, Leena Chaudhuri

Theses and Dissertations

Eukaryotic gene expression is a complex process and can be controlled at the level of transcription, post-transcription or translation and post-translation. In recent years, there is a growing interest in understanding the role of 3'-untranslated region (UTR) in regulating mRNA turnover and translation. The 3'-UTR harbors the poly(A) signal and post-transcriptional regulatory sequences like miRNA and AU-rich elements (AREs). The presence of multiple poly(A) sites often results in multiple transcripts; shorter transcripts correlating with more protein abundance. Manganese superoxide dismutase (MnSOD) is a nuclear encoded and mitochondrial matrix localized antioxidant enzyme that converts mitochondrial generated superoxide ...


The Role Of Ubiquitination Within The Endocytic Pathway, Daniel Kenneth Stringer Dec 2010

The Role Of Ubiquitination Within The Endocytic Pathway, Daniel Kenneth Stringer

Theses and Dissertations

Ubiquitination is a post-translational modification tht mediates sorting of integral membrane proteins to lysosomes for their degradation. ESCRTs (Endosomal Sorting Complex Required For Transport) bind and sequester ubiquitinated membrane proteins and direct them into multivesicular bodies (MVBs). ESCRTs themselves become covalently ubiquitinated, simply by virtue of non-covalently binding Ub. However, it is unclear whether this regulates a critical aspect of ESCRT function. In yeast, many MVB cargo proteins are ubiquitinated by the HECT-type Ub-ligase Rsp5, sometimes via the action of Rsp5 adaptor proteins. While many Rsp5 targets are modified by polyubiquitination, it remains unclear whether polyubiquitination is a necessary signal ...