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2012

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Articles 1 - 30 of 42

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

Advanced Molecular Biologic Techniques In Toxicologic Disease, Jeanine Ward, Gyongyi Szabo, David Mcmanus, Edward Boyer Oct 2012

Advanced Molecular Biologic Techniques In Toxicologic Disease, Jeanine Ward, Gyongyi Szabo, David Mcmanus, Edward Boyer

Gyongyi Szabo

The advancement of molecular biologic techniques and their capabilities to answer questions pertaining to mechanisms of pathophysiologic events have greatly expanded over the past few years. In particular, these opportunities have provided researchers and clinicians alike the framework from with which to answer clinical questions not amenable for elucidation using previous, more antiquated methods. Utilizing extremely small molecules, namely microRNA, DNA, protein, and nanoparticles, we discuss the background and utility of these approaches to the progressive, practicing physician. Finally, we consider the application of these tools employed as future bedside point of care tests, aiding in the ultimate goal of …

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Circulating Micrornas In Exosomes Indicate Hepatocyte Injury And Inflammation In Alcoholic, Drug-Induced, And Inflammatory Liver Diseases, Shashi Bala, Jan Petrasek, Shiv Mundkur, Donna Catalano, Ivan Levin, Jeanine Ward, Hawau Alao, Karen Kodys, Gyongyi Szabo Oct 2012

Circulating Micrornas In Exosomes Indicate Hepatocyte Injury And Inflammation In Alcoholic, Drug-Induced, And Inflammatory Liver Diseases, Shashi Bala, Jan Petrasek, Shiv Mundkur, Donna Catalano, Ivan Levin, Jeanine Ward, Hawau Alao, Karen Kodys, Gyongyi Szabo

Gyongyi Szabo

MicroRNAs are fine tuners of diverse biological responses and are expressed in various cell types of the liver. Here we hypothesized that circulating microRNAs (miRNAs) may serve as biomarkers of liver damage and inflammation. We studied miRNA-122, which is abundant in hepatocytes, and miR-155, -146a, and -125b, which regulate inflammation in immune cells in mouse models of alcoholic liver disease (ALD), drug (acetaminophen, APAP)-induced liver injury (DILI), and Toll-like receptor (TLR) 9+4 ligand-induced inflammatory cell-mediated liver damage. We found that serum/plasma miR-122 correlated with alanine aminotransferase (ALT) increases in the liver damage caused by alcohol, APAP, and TLR9 (CpG)+4 (LPS) …

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Consumption Of High Ω-3 Fatty Acid Diet Suppressed Prostate Tumorigenesis In C3(1) Tag Mice, Juliana Akinsete, Gabriela Ion, Theodore Witte, W. Hardman Oct 2012

Consumption Of High Ω-3 Fatty Acid Diet Suppressed Prostate Tumorigenesis In C3(1) Tag Mice, Juliana Akinsete, Gabriela Ion, Theodore Witte, W. Hardman

Gabriela Ion

Prostate cancer incidence and mortality are high in the Western world and high ω-6/ω-3 PUFA in the Western diet may be a contributing factor. We investigated whether changing from a diet that approximates ω-6 fat content of the Western diet to a high ω-3 fat diet at adulthood might reduce prostate cancer risk. Female SV 129 mice that had consumed a high ω-6 diet containing corn oil for 2 weeks were bred with homozygous C3(1)Tag transgenic male mice. All male offspring were weaned to the corn oil diet (CO) until postpuberty when half of the male offspring were transferred to …

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Quantitative Comparison Of Errors In 15n Transverse Relaxation Rates Measured Using Various Cpmg Phasing Schemes, Wazo Myint, Yufeng Cai, Celia Schiffer, Rieko Ishima Oct 2012

Quantitative Comparison Of Errors In 15n Transverse Relaxation Rates Measured Using Various Cpmg Phasing Schemes, Wazo Myint, Yufeng Cai, Celia Schiffer, Rieko Ishima

Celia A. Schiffer

Nitrogen-15 Carr-Purcell-Meiboom-Gill (CPMG) transverse relaxation experiment are widely used to characterize protein backbone dynamics and chemical exchange parameters. Although an accurate value of the transverse relaxation rate, R(2), is needed for accurate characterization of dynamics, the uncertainty in the R(2) value depends on the experimental settings and the details of the data analysis itself. Here, we present an analysis of the impact of CPMG pulse phase alternation on the accuracy of the (15)N CPMG R(2). Our simulations show that R(2) can be obtained accurately for a relatively wide spectral width, either using the conventional phase cycle or using phase alternation …

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Extreme Entropy-Enthalpy Compensation In A Drug-Resistant Variant Of Hiv-1 Protease, Nancy King, Moses Prabu-Jeyabalan, Rajintha Bandaranayake, Madhavi Nalam, Ellen Nalivaika, Aysegul Ozen, Turkan Haliloglu, Nese Yilmaz, Celia Schiffer Oct 2012

Extreme Entropy-Enthalpy Compensation In A Drug-Resistant Variant Of Hiv-1 Protease, Nancy King, Moses Prabu-Jeyabalan, Rajintha Bandaranayake, Madhavi Nalam, Ellen Nalivaika, Aysegul Ozen, Turkan Haliloglu, Nese Yilmaz, Celia Schiffer

Celia A. Schiffer

The development of HIV-1 protease inhibitors has been the historic paradigm of rational structure-based drug design, where structural and thermodynamic analyses have assisted in the discovery of novel inhibitors. While the total enthalpy and entropy change upon binding determine the affinity, often the thermodynamics are considered in terms of inhibitor properties only. In the current study, profound changes are observed in the binding thermodynamics of a drug-resistant variant compared to wild-type HIV-1 protease, irrespective of the inhibitor bound. This variant (Flap+) has a combination of flap and active site mutations and exhibits extremely large entropy-enthalpy compensation compared to wild-type protease, …

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Decomposing The Energetic Impact Of Drug-Resistant Mutations: The Example Of Hiv-1 Protease-Drv Binding, Yufeng Cai, Celia Schiffer Oct 2012

Decomposing The Energetic Impact Of Drug-Resistant Mutations: The Example Of Hiv-1 Protease-Drv Binding, Yufeng Cai, Celia Schiffer

Celia A. Schiffer

HIV-1 protease is a major drug target for AIDS therapy. With the appearance of drug-resistant HIV-1 protease variants, understanding the mechanism of drug resistance becomes critical for rational drug design. Computational methods can provide more details about inhibitor-protease binding than crystallography and isothermal titration calorimetry. The latest FDA-approved HIV-1 protease inhibitor is Darunavir (DRV). Herein, each DRV atom is evaluated by free energy component analysis for its contribution to the binding affinity with wild-type protease and ACT, a drug-resistant variant. This information can contribute to the rational design of new HIV-1 protease inhibitors.

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Mass Spectrometry Tools For Analysis Of Intermolecular Interactions, Jared Auclair, Mohan Somasundaran, Karin Green, James Evans, Celia Schiffer, Dagmar Ringe, Gregory Petsko, Jeffrey Agar Oct 2012

Mass Spectrometry Tools For Analysis Of Intermolecular Interactions, Jared Auclair, Mohan Somasundaran, Karin Green, James Evans, Celia Schiffer, Dagmar Ringe, Gregory Petsko, Jeffrey Agar

Celia A. Schiffer

The small quantities of protein required for mass spectrometry (MS) make it a powerful tool to detect binding (protein-protein, protein-small molecule, etc.) of proteins that are difficult to express in large quantities, as is the case for many intrinsically disordered proteins. Chemical cross-linking, proteolysis, and MS analysis, combined, are a powerful tool for the identification of binding domains. Here, we present a traditional approach to determine protein-protein interaction binding sites using heavy water ((18)O) as a label. This technique is relatively inexpensive and can be performed on any mass spectrometer without specialized software.

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The Molecular Basis Of Drug Resistance Against Hepatitis C Virus Ns3/4a Protease Inhibitors, Keith Romano, Akbar Ali, Cihan Aydin, Djade Soumana, Aysegul Ozen, Laura Deveau, Casey Silver, Hong Cao, Alicia Newton, Christos Petropoulos, Wei Huang, Celia Schiffer Oct 2012

The Molecular Basis Of Drug Resistance Against Hepatitis C Virus Ns3/4a Protease Inhibitors, Keith Romano, Akbar Ali, Cihan Aydin, Djade Soumana, Aysegul Ozen, Laura Deveau, Casey Silver, Hong Cao, Alicia Newton, Christos Petropoulos, Wei Huang, Celia Schiffer

Celia A. Schiffer

Hepatitis C virus (HCV) infects over 170 million people worldwide and is the leading cause of chronic liver diseases, including cirrhosis, liver failure, and liver cancer. Available antiviral therapies cause severe side effects and are effective only for a subset of patients, though treatment outcomes have recently been improved by the combination therapy now including boceprevir and telaprevir, which inhibit the viral NS3/4A protease. Despite extensive efforts to develop more potent next-generation protease inhibitors, however, the long-term efficacy of this drug class is challenged by the rapid emergence of resistance. Single-site mutations at protease residues R155, A156 and D168 confer …

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Context Surrounding Processing Sites Is Crucial In Determining Cleavage Rate Of A Subset Of Processing Sites In Hiv-1 Gag And Gag-Pro-Pol Polyprotein Precursors By Viral Protease, Sook-Kyung Lee, Marc Potempa, Madhavi Kolli, Aysegul Ozen, Celia Schiffer, Ronald Swanstrom Oct 2012

Context Surrounding Processing Sites Is Crucial In Determining Cleavage Rate Of A Subset Of Processing Sites In Hiv-1 Gag And Gag-Pro-Pol Polyprotein Precursors By Viral Protease, Sook-Kyung Lee, Marc Potempa, Madhavi Kolli, Aysegul Ozen, Celia Schiffer, Ronald Swanstrom

Celia A. Schiffer

Processing of the human immunodeficiency virus type 1 (HIV-1) Gag and Gag-Pro-Pol polyproteins by the HIV-1 protease (PR) is essential for the production of infectious particles. However, the determinants governing the rates of processing of these substrates are not clearly understood. We studied the effect of substrate context on processing by utilizing a novel protease assay in which a substrate containing HIV-1 matrix (MA) and the N-terminal domain of capsid (CA) is labeled with a FlAsH (fluorescein arsenical hairpin) reagent. When the seven cleavage sites within the Gag and Gag-Pro-Pol polyproteins were placed at the MA/CA site, the rates of …

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Structural, Kinetic, And Thermodynamic Studies Of Specificity Designed Hiv-1 Protease, Oscar Alvizo, Seema Mittal, Stephen Mayo, Celia Schiffer Oct 2012

Structural, Kinetic, And Thermodynamic Studies Of Specificity Designed Hiv-1 Protease, Oscar Alvizo, Seema Mittal, Stephen Mayo, Celia Schiffer

Celia A. Schiffer

HIV-1 protease recognizes and cleaves more than 12 different substrates leading to viral maturation. While these substrates share no conserved motif, they are specifically selected for and cleaved by protease during viral life cycle. Drug resistant mutations evolve within the protease that compromise inhibitor binding but allow the continued recognition of all these substrates. While the substrate envelope defines a general shape for substrate recognition, successfully predicting the determinants of substrate binding specificity would provide additional insights into the mechanism of altered molecular recognition in resistant proteases. We designed a variant of HIV protease with altered specificity using positive computational …

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Methyl- And Normal-Cytosine Deamination By The Foreign Dna Restriction Enzyme Apobec3a, Michael Carpenter, Ming Li, Anurag Rathore, Lela Lackey, Emily Law, Allison Land, Brandon Leonard, Shivender Shandilya, Markus-Frederik Bohn, Celia Schiffer, William Brown, Reuben Harris Oct 2012

Methyl- And Normal-Cytosine Deamination By The Foreign Dna Restriction Enzyme Apobec3a, Michael Carpenter, Ming Li, Anurag Rathore, Lela Lackey, Emily Law, Allison Land, Brandon Leonard, Shivender Shandilya, Markus-Frederik Bohn, Celia Schiffer, William Brown, Reuben Harris

Celia A. Schiffer

Multiple studies have indicated that the TET oxidases and, more controversially, the AID/APOBEC deaminases have the capacity to convert genomic DNA 5-methylcytosine (MeC) into altered nucleobases that provoke excision repair and culminate in the replacement of the original MeC with a normal cytosine (C). We show that human APOBEC3A (A3A) efficiently deaminates both MeC to thymine (T) and normal C to uracil (U) in single-stranded DNA substrates. In comparison, the related enzyme APOBEC3G (A3G) has undetectable MeC-to-T activity and 10-fold less C-to-U activity. Upon 100-fold induction of endogenous A3A by interferon, the MeC status of bulk chromosomal DNA is unaltered …

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Design, Synthesis, And Biological And Structural Evaluations Of Novel Hiv-1 Protease Inhibitors To Combat Drug Resistance, Maloy Parai, David Huggins, Hong Cao, Madhavi Nalam, Akbar Ali, Celia Schiffer, Bruce Tidor, Tariq Rana Oct 2012

Design, Synthesis, And Biological And Structural Evaluations Of Novel Hiv-1 Protease Inhibitors To Combat Drug Resistance, Maloy Parai, David Huggins, Hong Cao, Madhavi Nalam, Akbar Ali, Celia Schiffer, Bruce Tidor, Tariq Rana

Celia A. Schiffer

A series of new HIV-1 protease inhibitors (PIs) were designed using a general strategy that combines computational structure-based design with substrate-envelope constraints. The PIs incorporate various alcohol-derived P2 carbamates with acyclic and cyclic heteroatomic functionalities into the (R)-hydroxyethylamine isostere. Most of the new PIs show potent binding affinities against wild-type HIV-1 protease and three multidrug resistant (MDR) variants. In particular, inhibitors containing the 2,2-dichloroacetamide, pyrrolidinone, imidazolidinone, and oxazolidinone moieties at P2 are the most potent with K(i) values in the picomolar range. Several new PIs exhibit nanomolar antiviral potencies against patient-derived wild-type viruses from HIV-1 clades A, B, and C …

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Hydrophobic Core Flexibility Modulates Enzyme Activity In Hiv-1 Protease, Seema Mittal, Yufeng Cai, Madhavi Nalam, Daniel Bolon, Celia Schiffer Oct 2012

Hydrophobic Core Flexibility Modulates Enzyme Activity In Hiv-1 Protease, Seema Mittal, Yufeng Cai, Madhavi Nalam, Daniel Bolon, Celia Schiffer

Celia A. Schiffer

Human immunodeficiency virus Type-1 (HIV-1) protease is crucial for viral maturation and infectivity. Studies of protease dynamics suggest that the rearrangement of the hydrophobic core is essential for enzyme activity. Many mutations in the hydrophobic core are also associated with drug resistance and may modulate the core flexibility. To test the role of flexibility in protease activity, pairs of cysteines were introduced at the interfaces of flexible regions remote from the active site. Disulfide bond formation was confirmed by crystal structures and by alkylation of free cysteines and mass spectrometry. Oxidized and reduced crystal structures of these variants show the …

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Characterization Of The Monomer-Dimer Equilibrium Of Recombinant Histo-Aspartic Protease From Plasmodium Falciparum, Huogen Xiao, Lee-Ann Briere, Stanley Dunn, Rickey Yada Oct 2012

Characterization Of The Monomer-Dimer Equilibrium Of Recombinant Histo-Aspartic Protease From Plasmodium Falciparum, Huogen Xiao, Lee-Ann Briere, Stanley Dunn, Rickey Yada

Stanley D Dunn

Histo-aspartic protease (HAP) from Plasmodium falciparum is an intriguing aspartic protease due to its unique structure. Our previous study reported the first recombinant expression of soluble HAP, in its truncated form (lys77p-Leu328) (p denotes prosegment), as a thioredoxin (Trx) fusion protein Trx-tHAP. The present study found that the recombinant Trx-tHAP fusion protein aggregated during purification which could be prevented through the addition of 0.2% CHAPS. Trx-tHAP fusion protein was processed into a mature form of tHAP (mtHAP) by both autoactivation, and activation with either enterokinase or plasmepsin II. Using gel filtration chromatography as well as sedimentation velocity and equilibrium ultracentrifugation, …

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The B Subunits In The Peripheral Stalk Of F1f0 Atp Synthase Preferentially Adopt An Offset Relationship, Shane Claggett, Mac O'Neil Plancher, Stanley Dunn, Brian Cain Oct 2012

The B Subunits In The Peripheral Stalk Of F1f0 Atp Synthase Preferentially Adopt An Offset Relationship, Shane Claggett, Mac O'Neil Plancher, Stanley Dunn, Brian Cain

Stanley D Dunn

The peripheral stalk of F1F0 ATP synthase is essential for the binding of F1 to FO and for proper transfer of energy between the two sectors of the enzyme. The peripheral stalk of Escherichia coli is composed of a dimer of identical b subunits. In contrast, photosynthetic organisms express two b-like genes that form a heterodimeric peripheral stalk. Previously we generated chimeric peripheral stalks in which a portion of the tether and dimerization domains of the E. coli b subunits were replaced with homologous sequences from the b and b' subunits of Thermosynechococcus elongatus (Claggett, S. B., Grabar, T. B., …

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Functionally Compensating Coevolving Positions Are Neither Homoplasic Nor Conserved In Clades, Gregory Gloor, Gaurav Tyagi, Dana Abrassart, Andrew Kingston, Andrew Fernandes, Stanley Dunn, Christopher Brandl Oct 2012

Functionally Compensating Coevolving Positions Are Neither Homoplasic Nor Conserved In Clades, Gregory Gloor, Gaurav Tyagi, Dana Abrassart, Andrew Kingston, Andrew Fernandes, Stanley Dunn, Christopher Brandl

Stanley D Dunn

We demonstrated that a pair of positions in phosphoglycerate kinase that score highly by three nonparametric covariation measures are important for function even though the positions can be occupied by aliphatic, aromatic, or charged residues. Examination of these pairs suggested that the majority of the covariation scores could be explained by within-clade conservation. However, an analysis of diversity showed that the conservation within clades of covarying pairs was indistinguishable from pairs of positions that do not covary, thus ruling out both clade conservation and extensive homoplasy as means to identify covarying positions. Mutagenesis showed that the residues in the covarying …

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36 Degrees Step Size Of Proton-Driven C-Ring Rotation In Fof1-Atp Synthase, Monika Düser, Nawid Zarrabi, Daniel Cipriano, Stefan Ernst, Gary Glick, Stanley Dunn, Michael Börsch Oct 2012

36 Degrees Step Size Of Proton-Driven C-Ring Rotation In Fof1-Atp Synthase, Monika Düser, Nawid Zarrabi, Daniel Cipriano, Stefan Ernst, Gary Glick, Stanley Dunn, Michael Börsch

Stanley D Dunn

Synthesis of adenosine triphosphate ATP, the 'biological energy currency', is accomplished by F(o)F(1)-ATP synthase. In the plasma membrane of Escherichia coli, proton-driven rotation of a ring of 10 c subunits in the F(o) motor powers catalysis in the F(1) motor. Although F(1) uses 120 degrees stepping during ATP synthesis, models of F(o) predict either an incremental rotation of c subunits in 36 degrees steps or larger step sizes comprising several fast substeps. Using single-molecule fluorescence resonance energy transfer, we provide the first experimental determination of a 36 degrees sequential stepping mode of the c-ring during ATP synthesis.

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Re-Introduction Of Transmembrane Serine Residues Reduce The Minimum Pore Diameter Of Channelrhodopsin-2, Robert Dempski, Ryan Richards Sep 2012

Re-Introduction Of Transmembrane Serine Residues Reduce The Minimum Pore Diameter Of Channelrhodopsin-2, Robert Dempski, Ryan Richards

Robert E. Dempski

Channelrhodopsin-2 (ChR2) is a microbial-type rhodopsin found in the green algae Chlamydomonas reinhardtii. Under physiological conditions, ChR2 is an inwardly rectifying cation channel that permeates a wide range of mono- and divalent cations. Although this protein shares a high sequence homology with other microbial-type rhodopsins, which are ion pumps, ChR2 is an ion channel. A sequence alignment of ChR2 with bacteriorhodopsin, a proton pump, reveals that ChR2 lacks specific motifs and residues, such as serine and threonine, known to contribute to non-covalent interactions within transmembrane domains. We hypothesized that reintroduction of the eight transmembrane serine residues present in bacteriorhodopsin, but …

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First-In-Class Small Molecule Inhibitors Of The Single-Strand Dna Cytosine Deaminase Apobec3g, Ming Li, Shivender Shandilya, Michael Carpenter, Anurag Rathore, William Brown, Angela Perkins, Daniel Harki, Jonathan Solberg, Derek Hook, Krishan Pandey, Michael Parniak, Jeffrey Johnson, Nevan Krogan, Mohan Somasundaran, Akbar Ali, Celia Schiffer, Reuben Harris Sep 2012

First-In-Class Small Molecule Inhibitors Of The Single-Strand Dna Cytosine Deaminase Apobec3g, Ming Li, Shivender Shandilya, Michael Carpenter, Anurag Rathore, William Brown, Angela Perkins, Daniel Harki, Jonathan Solberg, Derek Hook, Krishan Pandey, Michael Parniak, Jeffrey Johnson, Nevan Krogan, Mohan Somasundaran, Akbar Ali, Celia Schiffer, Reuben Harris

Celia A. Schiffer

APOBEC3G is a single-stranded DNA cytosine deaminase that comprises part of the innate immune response to viruses and transposons. Although APOBEC3G is the prototype for understanding the larger mammalian polynucleotide deaminase family, no specific chemical inhibitors exist to modulate its activity. High-throughput screening identified 34 compounds that inhibit APOBEC3G catalytic activity. Twenty of 34 small molecules contained catechol moieties, which are known to be sulfhydryl reactive following oxidation to the orthoquinone. Located proximal to the active site, C321 was identified as the binding site for the inhibitors by a combination of mutational screening, structural analysis, and mass spectrometry. Bulkier substitutions …

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Structural Insights Into Neuronal K+ Channel-Calmodulin Complexes, Karen Mruk, Shivender Shandilya, Robert Blaustein, Celia Schiffer, William Kobertz Sep 2012

Structural Insights Into Neuronal K+ Channel-Calmodulin Complexes, Karen Mruk, Shivender Shandilya, Robert Blaustein, Celia Schiffer, William Kobertz

Celia A. Schiffer

Calmodulin (CaM) is a ubiquitous intracellular calcium sensor that directly binds to and modulates a wide variety of ion channels. Despite the large repository of high-resolution structures of CaM bound to peptide fragments derived from ion channels, there is no structural information about CaM bound to a fully folded ion channel at the plasma membrane. To determine the location of CaM docked to a functioning KCNQ K(+) channel, we developed an intracellular tethered blocker approach to measure distances between CaM residues and the ion-conducting pathway. Combining these distance restraints with structural bioinformatics, we generated an archetypal quaternary structural model of …

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Morphology And Fracture Of Enamel, Sangwon Myoung, James Lee, Paul Constantino, Peter Lucas, Herzl Chai, Brian Law Sep 2012

Morphology And Fracture Of Enamel, Sangwon Myoung, James Lee, Paul Constantino, Peter Lucas, Herzl Chai, Brian Law

Paul J. Constantino

This study examines the inter-relation between enamel morphology and crack resistance by sectioning extracted human molars after loading to fracture. Cracks appear to initiate from tufts, hypocalcified defects at the enamel–dentin junction, and grow longitudinally around the enamel coat to produce failure. Microindentation corner cracks placed next to the tufts in the sections deflect along the tuft interfaces and occasionally penetrate into the adjacent enamel. Although they constitute weak interfaces, the tufts are nevertheless filled with organic matter, and appear to be stabilized against easy extension by self-healing, as well as by mutual stress-shielding and decussation, accounting at least in …

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Microwear, Mechanics And The Feeding Adaptations Of Australopithecus Africanus, Paul Constantino, Craig Byron, Paul Dechow, Ian Gross, Peter Lucas, Brian Richmond, Callum Ross, Dennis Slice, Mark Spencer, Dennis Strait, Qian Wang, Gerhard Weber, Bernard Wood, Barth Wright Sep 2012

Microwear, Mechanics And The Feeding Adaptations Of Australopithecus Africanus, Paul Constantino, Craig Byron, Paul Dechow, Ian Gross, Peter Lucas, Brian Richmond, Callum Ross, Dennis Slice, Mark Spencer, Dennis Strait, Qian Wang, Gerhard Weber, Bernard Wood, Barth Wright

Paul J. Constantino

Recent studies of dental microwear and craniofacial mechanics have yielded contradictory interpretations regarding the feeding ecology and adaptations of Australopithecus africanus. As part of this debate, the methods used in the mechanical studies have been criticized. In particular, it has been claimed that finite element analysis has been poorly applied to this research question. This paper responds to some of these mechanical criticisms, highlights limitations of dental microwear analysis, and identifies avenues of future research.

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Purification And Characterization Of Novel Nucleases From A Thermophilic Fungus, Kyle Landry Sep 2012

Purification And Characterization Of Novel Nucleases From A Thermophilic Fungus, Kyle Landry

Kyle S Landry

A thermophilic fungus was isolated from composted horse manure. The organism was as a Chaetomium sp. by sequencing the highly conserved ITS region of the fungus and comparing to known regions in a genomic database and was referred to as TM-417. TM-417 was found to have an optimal growth temperature of 45 oC and an optimal pH of 7.0. An extracellular DNase and RNase was found to be produced by the isolate and were purified 145.58-fold and 127.6-fold respectively using a combination of size exclusion chromatography and a novel affinity membrane purification system. The extent of purification was determined …

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Non-Helicobacter Pylori Related Duodenal Ulcer Disease In Children, Yoram Elitsur, Zandra Lawrence Sep 2012

Non-Helicobacter Pylori Related Duodenal Ulcer Disease In Children, Yoram Elitsur, Zandra Lawrence

Yoram Elitsur

Background. In spite of the worldwide distribution of Helicobacter pylori infection, recent data have reported an increased rate of non-H. pylori, non-NSAIDs-duodenal ulcer disease in adults. The estimated rate of these ulcers in children is unknown. We aimed to investigate the prevalence of non-H. pylori, non-NSAIDs-peptic ulcer disease in our pediatric patients who undergo upper endoscopic procedures. Methods. A retrospective analysis of 622 upper endoscopic reports was performed. Reports that documented mucosal ulcerations were included in our study. The demographic, clinical, endoscopic, and histological data were retrieved. The H. pylori-negative, duodenal/gastric ulcer-positive patients were compared with H. pylori-positive, duodenal/gastric ulcer-positive …

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Is Sudden Infant Death Syndrome Associated With Helicobacter Pylori Infection In Children?, Yoram Elitsur, William Btriest, Zia Sabet, Cheryl Neace, Chuancang Jiang, Eapen Thomas Sep 2012

Is Sudden Infant Death Syndrome Associated With Helicobacter Pylori Infection In Children?, Yoram Elitsur, William Btriest, Zia Sabet, Cheryl Neace, Chuancang Jiang, Eapen Thomas

Yoram Elitsur

Helicobacter pylori infection has recently been implicated in the pathogenesis of sudden infant death syndrome (SIDS). We investigated this association. Twenty-five pairs of gastric and tracheal tissue specimens obtained from autopsies of 25 children with previous diagnoses of SIDS were available for this study. The presence of H. pylori organisms was evaluated by three different methods: histology (hematoxylin-eosin or Giemsa staining), immunohistochemistry, and nested polymerase chain reaction technique. We were unable to confirm the presence of H. pylori organisms by the first two methods. H. pylori DNA was identified by nested polymerase chain reaction in six different tissue specimens (stomach, …

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Global Analysis Of Gene Expression Changes During Retinoic Acid-Induced Growth Arrest And Differentiation Of Melanoma: Comparison To Differentially Expressed Genes In Melanocytes Vs Melanoma, Mary Estler, Goran Boskovic, James Denvir, Sarah Miles, Donald Primerano, Richard Niles Sep 2012

Global Analysis Of Gene Expression Changes During Retinoic Acid-Induced Growth Arrest And Differentiation Of Melanoma: Comparison To Differentially Expressed Genes In Melanocytes Vs Melanoma, Mary Estler, Goran Boskovic, James Denvir, Sarah Miles, Donald Primerano, Richard Niles

James Denvir

BACKGROUND: The incidence of malignant melanoma has significantly increased over the last decade. Some of these malignancies are susceptible to the growth inhibitory and pro-differentiating effects of all-trans-retinoic acid (RA). The molecular changes responsible for the biological activity of RA in melanoma are not well understood. RESULTS: In an analysis of sequential global gene expression changes during a 4-48 h RA treatment of B16 mouse melanoma cells, we found that RA increased the expression of 757 genes and decreased the expression of 737 genes. We also compared the gene expression profile (no RA treatment) between non-malignant melan-a mouse melanocytes and …

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A High Omega-3 Fatty Acid Diet Has Different Effects On Early And Late Stage Myeloid Progenitors, Melinda Varney, James Buchanan, Yulia Dementieva, W. Hardman, Vincent Sollars Aug 2012

A High Omega-3 Fatty Acid Diet Has Different Effects On Early And Late Stage Myeloid Progenitors, Melinda Varney, James Buchanan, Yulia Dementieva, W. Hardman, Vincent Sollars

Elaine Hardman Ph.D.

The effects of the polyunsaturated omega-3 (n-3) and omega-6 (n-6) fatty acids (FA) on hematopoiesis are complex in that both FA forms are processed into leukotrienes, eicosanoids, and prostaglandins, which can have independent effects. These FA have antagonistic effects in that n-6 FA prostaglandins tend to be pro-proliferative and pro-inflammatory, while the effects of n-3 FA prostaglandins are the opposite. We have previously shown that diets high in n-3 FA reduce the size of the middle to later stage myeloid progenitor compartment in FVB X sv129 F1hybrid mice. To assay the effects of high n-3 FA diets on earlier stages …

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Analysis Of Expansion Of Myeloid Progenitors In Mice To Identify Leukemic Susceptibility Genes, Vincent Sollars, Ed Pequignot, Jay Rothstein, Arthur Buchberg Aug 2012

Analysis Of Expansion Of Myeloid Progenitors In Mice To Identify Leukemic Susceptibility Genes, Vincent Sollars, Ed Pequignot, Jay Rothstein, Arthur Buchberg

Vincent E Sollars

The myeloid progenitor cell compartment (MPC) exhibits pronounced expansion in human myeloid leukemias. It is becoming more apparent that progression of myelodysplastic syndromes and myeloproliferative diseases to acute myelogenous leukemia is the result of defects in progenitor cell maturation. The MPC of bone marrow was analyzed in mice using a cell culture assay for measuring the relative frequency of proliferative myeloid progenitors. Response to the cytokines SCF, IL-3, and GMCSF was determined by this assay for the leukemic mouse strain BXH-2 and ten other inbred mouse strains. Significant differences were found to exist among ten inbred mouse strains in the …

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Epigenetic Modification As An Enabling Mechanism For Leukemic Transformation, Vincent Sollars Aug 2012

Epigenetic Modification As An Enabling Mechanism For Leukemic Transformation, Vincent Sollars

Vincent E Sollars

Cancer is now thought of as a fundamentally genetic disease, in that changes in the genome result in aberrant gene expression of oncogenes and tumor suppressor genes to promote oncogenesis. However, with our increasing knowledge of gene regulation, it is becoming obvious that changes in nucleotide sequence are not the sole mechanism for eliciting changes in transcription. An additional layer of regulation of gene expression, called epigenetics, is now being realized as increasingly important in oncogenesis. Epigenetics is defined as non-sequence based changes in chromatin that elicit changes in gene expression that are propagated through mitosis and/or meiosis. The alleles …

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Membrane Fusion Proteins Are Required For Oskar Mrna Localization In The Drosophila Egg Chamber, Douglas Ruden, Vincent Sollars, Xiaoyan Wang, Daisuke Mori, Marina Alterman, Xiangyi Lu Aug 2012

Membrane Fusion Proteins Are Required For Oskar Mrna Localization In The Drosophila Egg Chamber, Douglas Ruden, Vincent Sollars, Xiaoyan Wang, Daisuke Mori, Marina Alterman, Xiangyi Lu

Vincent E Sollars

We used a genetic screen in Drosophila to identify mutations which disrupt the localization of oskar mRNA during oogenesis. Based on the hypothesis that some cytoskeletal components which are required during the mitotic divisions will also be required for oskar mRNA localization during oogenesis, we designed the following genetic screen. We screened for P-element insertions in genes which slow down the blastoderm mitotic divisions. A secondary genetic screen was to generate female germ-line clones of these potential cell division cycle genes and to identify those which cause the mislocalization of oskar mRNA. We identified mutations in ter94 which disrupt the …

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