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Sample records for preoccluded virion synthesis

  1. Mutations in the Primer Grip of Human Immunodeficiency Virus Type 1 Reverse Transcriptase Impair Proviral DNA Synthesis and Virion Maturation

    Science.gov (United States)

    Yu, Qiang; Ottmann, Michele; Pechoux, Christine; Le Grice, Stuart; Darlix, Jean-Luc

    1998-01-01

    This report describes the effects of mutating highly conserved residues in the primer grip domain of human immunodeficiency virus type 1 reverse transcriptase (RT) on virus formation and infectivity. Among a series of RT mutant viruses, three (M230A, L234D, and W239A) were found to be noninfectious or very poorly infectious. Our data indicate that these mutations in RT caused severe defects in proviral DNA synthesis. Interestingly, assembly and maturation of mutant virus M230A were similar to those of the wild type, while mutants L234D and W239A showed impaired maturation. The immature morphology of RT mutants L234D and W239A is due at least in part to premature cleavage of the gag-pol precursor, prior to virion budding, indicating that intracellular stability of Pr160gag-pol is of key importance during virus assembly. PMID:9696874

  2. Selective Inhibition of the Synthesis of Sindbis Virion Proteins by an Inhibitor of Chymotrypsin

    Science.gov (United States)

    Pfefferkorn, E. R.; Boyle, Mary K.

    1972-01-01

    Treatment of chick embryo fibroblasts infected with Sindbis virus with TPCK, the choloromethyl ketone derivative of tosyl-phenylalanine and an inhibitor of chymotrypsin, resulted in reduced synthesis of viral structural proteins and the accumulation of a high-molecular-weight polypeptide, thought to be a precursor. The analogous inhibitor of trypsin, TLCK, the chloromethyl ketone derivative of tosyllysine, had no such effect. PMID:5061988

  3. Herpes simplex virus mutants defective in the virion-associated shutoff of host polypeptide synthesis and exhibiting abnormal synthesis of alpha (immediate early) viral polypeptides.

    Science.gov (United States)

    Read, G S; Frenkel, N

    1983-05-01

    Six mutants isolated from herpes simplex virus type 1 were judged to be defective with respect to the virion-associated function acting to rapidly shut off host polypeptide synthesis in herpes simplex virus-infected cells. The mutants were capable of proper entry into the cells, but, unlike the parent wild-type virus, they failed to shut off host polypeptide syntehsis in the presence of actinomycin D. They were consequently designated as virion-associated host shutoff (vhs) mutants. In the presence of actinomycin D, three of the mutants, vhs1, -2, and -3, failed to shut off the host at both 34 and 39 degrees C, whereas vhs4, -5, and -6 exhibited a temperature-dependent vhs phenotype. Since the mutants were capable of growth at 34 degrees C, it appeared that the vhs function was not essential for virus replication in cultured cells. Temperature-shift experiments performed with the vhs4 mutant showed that an active vhs function was required throughout the shutoff process and that, once established, the translational shutoff could not be reversed. In the absence of actinomycin D, the mutants induced a generalized, secondary shutoff of host translation, which required the synthesis of beta (early) or gamma (late) viral polypeptide(s). The vhs mutants appeared to be defective also with respect to post-transcriptional shutoff of alpha (immediate early) viral gene expression, since (i) cells infected with mutant viruses overproduced alpha viral polypeptides, (ii) there was an increased functional stability of alpha mRNA in the vhs1 mutant virus-infected cells, and (iii) superinfection of vhs1-infected cells with wild-type virus, in the presence of actinomycin D, resulted in a more pronounced shutoff of alpha polypeptide synthesis from preformed alpha mRNA than equivalent superinfection with vhs1 virus. The data suggest that the synthesis of alpha polypeptides in wild-type virus infections is subject to a negative post-transcriptional control involving viral gene product

  4. Differentiation of the shutoff of protein synthesis by virion host shutoff and mutant gamma (1)34.5 genes of herpes simplex virus 1.

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    Poon, A P; Roizman, B

    1997-03-01

    vhs protein is the product of the UL41 open reading frame of herpes simplex virus 1. The protein, made late in infection, is packaged into virions and, in newly infected cells, shuts off host protein synthesis by degrading mRNA. gamma (1)34.5 gene encodes a protein which precludes total shutoff of protein synthesis after the onset of viral DNA synthesis in infected cells of human derivation. The experiments reported here were designed to test the hypothesis that in cells infected with gamma (1)34.5- mutant the total shutoff of protein synthesis reflects the failure to alter the function of vhs made late in infection. Hence, double mutants, vhs- and gamma (1)34.5 should not cause total shutoff of protein synthesis. The mutants constructed to test the hypothesis were (i) viruses lacking 1 kbp from the coding domain of gamma (1)34.5 and carrying lacZ inserted into the coding domain of UI41, (ii) viruses with deletions in gamma (1)34.5 genes, (iii) viruses with lacZ inserted into UL41, and (iv) viruses in which the sequences of the deleted or interrupted genes were restored. We report that viruses with wild-type UL41 gene shut off the synthesis of actin, whereas viruses with interrupted genes made amounts of actin comparable to those of mock-infected cells. However, late in infection, protein synthesis in human neuroblastoma cells infected with the gamma (1)34.5- mutants was shut off irrespective of the status of the UL41 gene. Conversely, the phenotype of UI41 viruses with wild-type gamma (1)34.5 gene could not be differentiated from those of wild-type virus in the same assays. These studies indicate that the functions of the UL41 and gamma (1)34.5 genes and their products are independent of each other.

  5. Herpes simplex virus virion host shutoff function.

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    Kwong, A D; Kruper, J A; Frenkel, N

    1988-03-01

    Herpes simplex virus (HSV) virions contain one or more functions which mediate the shutoff of host protein synthesis and the degradation of host mRNA. HSV type 1 (HSV-1) mutants deficient in the virion shutoff of host protein synthesis (vhs mutants) were isolated and were found to be defective in their ability to degrade host mRNA. Furthermore, it was found that viral mRNAs in cells infected with the vhs 1 mutant have a significantly longer functional half-life than viral mRNAs in wild-type virus-infected cells. In the present study we have mapped the vhs1 mutation affecting the virion shutoff of host protein synthesis to a 265-base-pair NruI-XmaIII fragment spanning map coordinates 0.604 to 0.606 of the HSV-1 genome. The mutation(s) affecting the functional half-lives of host mRNA as well as the alpha (immediate-early), beta (early), and gamma (late) viral mRNAs were also mapped within this 265-base-pair fragment. Thus, the shutoff of host protein synthesis is most likely mediated by the same function which decreases the half-life of viral mRNA. The shorter half-life of infected-cell mRNAs may allow a more rapid modulation of viral gene expression in response to changes in the transcription of viral genes. Interestingly, the vhs1 mutation of HSV-1 maps within a region which overlaps the Bg/II-N sequences of HSV-2 DNA shown previously to transform cells in culture. The possible relationship between the transformation and host shutoff functions are discussed.

  6. Kinetics of Incorporation of Structural Proteins into Sindbis Virions

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    Scheele, Christina M.; Pfefferkorn, E. R.

    1969-01-01

    The morphogenesis of Sindbis virus was studied by determining the kinetics with which newly synthesized nucleocapsid and envelope proteins appeared in virions released into the extracellular medium. Assembly of the nucleocapsid was more rapid than modification of the cellular membrane by the addition of the viral envelope protein. However, both viral structural proteins were efficiently incorporated into virions; a 0.5-hr pulse-labeling period resulted in the release of maximally labeled virus during the next hour. When protein synthesis was inhibited, release of virus soon declined even though large amounts of both viral structural proteins were present within the cell and ribonucleic acid replication was unaffected. PMID:5771964

  7. Retroviral Env Glycoprotein Trafficking and Incorporation into Virions

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    Tsutomu Murakami

    2012-01-01

    Full Text Available Together with the Gag protein, the Env glycoprotein is a major retroviral structural protein and is essential for forming infectious virus particles. Env is synthesized, processed, and transported to certain microdomains at the plasma membrane and takes advantage of the same host machinery for its trafficking as that used by cellular glycoproteins. Incorporation of Env into progeny virions is probably mediated by the interaction between Env and Gag, in some cases with the additional involvement of certain host factors. Although several general models have been proposed to explain the incorporation of retroviral Env glycoproteins into virions, the actual mechanism for this process is still unclear, partly because structural data on the Env protein cytoplasmic tail is lacking. This paper presents the current understanding of the synthesis, trafficking, and virion incorporation of retroviral Env proteins.

  8. Virion component of herpes simplex virus type 1 KOS interferes with early shutoff of host protein synthesis induced by herpes simplex virus type 2 186.

    OpenAIRE

    Hill, T M; Sadler, J R; Betz, J L

    1985-01-01

    Herpes simplex virus (HSV) strains HSV type 1 (HSV-1) KOS and HSV-2 186 are representative of delayed and early shutoff strains, respectively, with regard to their ability to inhibit protein synthesis in Friend erythroleukemia cells. When these cells were simultaneously infected with HSV-1 KOS and HSV-2 186, HSV-1 KOS interfered with the rapid suppression of globin synthesis induced by HSV-2 186. The observed interference was competitive and not due to exclusion of HSV-2 by HSV-1 at the level...

  9. Morphogenesis of the infectious HIV-1 virion

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    Jun-Ichi eSakuragi

    2011-12-01

    Full Text Available The virion of HIV-1 is spherical and viral glycoprotein spikes (gp120, gp41 protrude from its envelope. The characteristic cone-shaped core exists within the virion, caging the ribonucleoprotein (RNP complex, which is comprised of viral RNA, nucleocapsid (NC and viral enzymes. The HIV-1 virion is budded and released from the infected cell as an immature donut-shaped particle. During or immediately after release, viral protease (PR is activated and subsequently processes the viral structural protein Gag. Through this maturation process, virions acquire infectivity, but its mechanism and transition of morphology largely remain unclear. Recent technological advances in experimental devices and techniques have made it possible to closely dissect the viral production site on the cell, the exterior – or even the interior – of an individual virion, and many new aspects on virion morphology and maturation. In this manuscript, I review the morphogenesis of HIV-1 virions. I focus on several studies, including some of our recent findings, which examined virion formation and/or maturation processes. The story of novel compound, which inhibits virion maturation, and the importance of maturation research are also discussed.

  10. The herpes simplex virus virion host shutoff function.

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    Kwong, A D; Frenkel, N

    1989-11-01

    The virion host shutoff (vhs) function of herpes simplex virus (HSV) limits the expression of genes in the infected cells by destabilizing both host and viral mRNAs. vhs function mutants have been isolated which are defective in their ability to degrade host mRNA. Furthermore, the half-life of viral mRNAs is significantly longer in cells infected with the vhs-1 mutant virus than in cells infected with the wild-type (wt) virus. Recent data have shown that the vhs-1 mutation resides within the open reading frame UL41. We have analyzed the shutoff of host protein synthesis in cells infected with a mixture of the wt HSV-1 (KOS) and the vhs-1 mutant virus. The results of these experiments revealed that (i) the wt virus shutoff activity requires a threshold level of input virions per cell and (ii) the mutant vhs-1 virus protein can irreversibly block the wt virus shutoff activity. These results are consistent with a stoichiometric model in which the wt vhs protein interacts with a cellular factor which controls the half-life of cell mRNA. This wt virus interaction results in the destabilization of both host and viral mRNAs. In contrast, the mutant vhs function interacts with the cellular factor irreversibly, resulting in the increased half-life of both host and viral mRNAs.

  11. Structural lability of Barley stripe mosaic virus virions.

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    Valentin V Makarov

    Full Text Available Virions of Barley stripe mosaic virus (BSMV were neglected for more than thirty years after their basic properties were determined. In this paper, the physicochemical characteristics of BSMV virions and virion-derived viral capsid protein (CP were analyzed, namely, the absorption and intrinsic fluorescence spectra, circular dichroism spectra, differential scanning calorimetry curves, and size distributions by dynamic laser light scattering. The structural properties of BSMV virions proved to be intermediate between those of Tobacco mosaic virus (TMV, a well-characterized virus with rigid rod-shaped virions, and flexuous filamentous plant viruses. The BSMV virions were found to be considerably more labile than expected from their rod-like morphology and a distant sequence relation of the BSMV and TMV CPs. The circular dichroism spectra of BSMV CP subunits incorporated into the virions, but not subunits of free CP, demonstrated a significant proportion of beta-structure elements, which were proposed to be localized mostly in the protein regions exposed on the virion outer surface. These beta-structure elements likely formed during virion assembly can comprise the N- and C-terminal protein regions unstructured in the non-virion CP and can mediate inter-subunit interactions. Based on computer-assisted structure modeling, a model for BSMV CP subunit structural fold compliant with the available experimental data was proposed.

  12. Virion Proteomics of Large DNA Viruses

    Institute of Scientific and Technical Information of China (English)

    Ran-ran WANG; Zhi-hong HU; Hua-lin WANG; Fei DENG

    2009-01-01

    Large DNA viruses normally have complex structures with many of protein components derived from both viral and host origins. The development in proteomics, especially mass spectrometry identification techniques provide powerful tools for analyzing large viruses. In this review, we have summarized the recent achievements on proteomic studies of large DNA viruses, such as herpesvirus, poxvirus, nimavirus and baculoviruse. The proteomics of baculovirus occlusion-derived virions (ODV) were emphasized. Different mass spectrometry techniques used on ,carious baculoviruses were introduced, and the identified structurally associated proteins of baculoviruses are summarized.

  13. Scaling, crumpled wires, and genome packing in virions

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    de Holanda, V. H.; Gomes, M. A. F.

    2016-12-01

    The packing of a genome in virions is a topic of intense current interest in biology and biological physics. The area is dominated by allometric scaling relations that connect, e.g., the length of the encapsulated genome and the size of the corresponding virion capsid. Here we report scaling laws obtained from extensive experiments of packing of a macroscopic wire within rigid three-dimensional spherical and nonspherical cavities that can shed light on the details of the genome packing in virions. We show that these results obtained with crumpled wires are comparable to those from a large compilation of biological data from several classes of virions.

  14. RNA-Dependent RNA Polymerase Activity in Influenza Virions

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    Penhoet, Edward; Miller, Henry; Doyle, Michael; Blatti, Stanley

    1971-01-01

    An RNA-dependent RNA polymerase activity has been detected in purified preparations of influenza virus. In contrast to the replicase activity induced in influenza-infected cells, the virion-associated enzyme has an absolute requirement for Mn++. Most of the RNA synthesized in vitro is complementary to virion RNA. PMID:5288388

  15. Proteomic characterization of murid herpesvirus 4 extracellular virions.

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    Sarah Vidick

    Full Text Available Gammaherpesvirinae, such as the human Epstein-Barr virus (EBV and the Kaposi's sarcoma associated herpesvirus (KSHV are highly prevalent pathogens that have been associated with several neoplastic diseases. As EBV and KSHV are host-range specific and replicate poorly in vitro, animal counterparts such as Murid herpesvirus-4 (MuHV-4 have been widely used as models. In this study, we used MuHV-4 in order to improve the knowledge about proteins that compose gammaherpesviruses virions. To this end, MuHV-4 extracellular virions were isolated and structural proteins were identified using liquid chromatography tandem mass spectrometry-based proteomic approaches. These analyses allowed the identification of 31 structural proteins encoded by the MuHV-4 genome which were classified as capsid (8, envelope (9, tegument (13 and unclassified (1 structural proteins. In addition, we estimated the relative abundance of the identified proteins in MuHV-4 virions by using exponentially modified protein abundance index analyses. In parallel, several host proteins were found in purified MuHV-4 virions including Annexin A2. Although Annexin A2 has previously been detected in different virions from various families, its role in the virion remains controversial. Interestingly, despite its relatively high abundance in virions, Annexin A2 was not essential for the growth of MuHV-4 in vitro. Altogether, these results extend previous work aimed at determining the composition of gammaherpesvirus virions and provide novel insights for understanding MuHV-4 biology.

  16. From Crescent to Mature Virion: Vaccinia Virus Assembly and Maturation

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    Liang Liu

    2014-10-01

    Full Text Available Vaccinia virus (VACV has achieved unprecedented success as a live viral vaccine for smallpox which mitigated eradication of the disease. Vaccinia virus has a complex virion morphology and recent advances have been made to answer some of the key outstanding questions, in particular, the origin and biogenesis of the virion membrane, the transformation from immature virion (IV to mature virus (MV, and the role of several novel genes, which were previously uncharacterized, but have now been shown to be essential for VACV virion formation. This new knowledge will undoubtedly contribute to the rational design of safe, immunogenic vaccine candidates, or effective antivirals in the future. This review endeavors to provide an update on our current knowledge of the VACV maturation processes with a specific focus on the initiation of VACV replication through to the formation of mature virions.

  17. Acceleration of adenovirus replication and increased virion production by treatment with the steroid hormone 17 beta-estradiol.

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    James, C B; Vanderpool, E A; Roane, P

    1992-01-01

    We report here that concentration of an estrogen known to promote enhanced transformation and to increase oncogenicity of rat embryo cells, accelerate the production and increase the yield of progeny virions in adenovirus type 12 (Ad 12)-infected HEp-2 cells. Further, measurement of the incorporation of radioactive RNA and DNA precursors indicated that macromolecular synthesis in the estrogen-treated, infected cells was accelerated. Possible explanations for this observation are discussed.

  18. Protein Primary Structure of the Vaccinia Virion at Increased Resolution

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    Ngo, Tuan; Mirzakhanyan, Yeva; Moussatche, Nissin; Gershon, Paul David

    2016-11-01

    Here we examine the protein covalent structure of the vaccinia virus virion. Within two virion preparations, >88% of the theoretical vaccinia virus-encoded proteome was detected with high confidence, including the first detection of products from 27 open reading frames (ORFs) previously designated "predicted," "uncharacterized," "inferred," or "hypothetical" polypeptides containing as few as 39 amino acids (aa) and six proteins whose detection required nontryptic proteolysis. We also detected the expression of four short ORFs, each of which was located within an ORF ("ORF-within-ORF"), including one not previously recognized or known to be expressed. Using quantitative mass spectrometry (MS), between 58 and 74 proteins were determined to be packaged. A total of 63 host proteins were also identified as candidates for packaging. Evidence is provided that some portion of virion proteins are "nicked" via a combination of endoproteolysis and concerted exoproteolysis in a manner, and at sites, independent of virus origin or laboratory procedures. The size of the characterized virion phosphoproteome was doubled from 189 (J. Matson, W. Chou, T. Ngo, and P. D. Gershon, Virology 452-453:310-323, 2014, doi:http://dx.doi.org/10.1016/j.virol.2014.01.012) to 396 confident, unique phosphorylation sites, 268 of which were within the packaged proteome. This included the unambiguous identification of phosphorylation "hot spots" within virion proteins. Using isotopically enriched ATP, 23 sites of intravirion kinase phosphorylation were detected within nine virion proteins, all at sites already partially occupied within the virion preparations. The clear phosphorylation of proteins RAP94 and RP19 was consistent with the roles of these proteins in intravirion early gene transcription. In a blind search for protein modifications, cysteine glutathionylation and O-linked glycosylation featured prominently. We provide evidence for the phosphoglycosylation of vaccinia virus proteins.

  19. Incorporation of Spike and Membrane Glycoproteins into Coronavirus Virions

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    Makoto Ujike

    2015-04-01

    Full Text Available The envelopes of coronaviruses (CoVs contain primarily three proteins; the two major glycoproteins spike (S and membrane (M, and envelope (E, a non-glycosylated protein. Unlike other enveloped viruses, CoVs bud and assemble at the endoplasmic reticulum (ER-Golgi intermediate compartment (ERGIC. For efficient virion assembly, these proteins must be targeted to the budding site and to interact with each other or the ribonucleoprotein. Thus, the efficient incorporation of viral envelope proteins into CoV virions depends on protein trafficking and protein–protein interactions near the ERGIC. The goal of this review is to summarize recent findings on the mechanism of incorporation of the M and S glycoproteins into the CoV virion, focusing on protein trafficking and protein–protein interactions.

  20. Inhibition of protein kinase C phosphorylation of hepatitis B virus capsids inhibits virion formation and causes intracellular capsid accumulation.

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    Wittkop, Linda; Schwarz, Alexandra; Cassany, Aurelia; Grün-Bernhard, Stefanie; Delaleau, Mildred; Rabe, Birgit; Cazenave, Christian; Gerlich, Wolfram; Glebe, Dieter; Kann, Michael

    2010-07-01

    Capsids of hepatitis B virus and other hepadnaviruses contain a cellular protein kinase, which phosphorylates the capsid protein. Some phosphorylation sites are shown to be essential for distinct steps of viral replication as pregenome packaging or plus strand DNA synthesis. Although different protein kinases have been reported to phosphorylate the capsid protein, varying experimental approaches do not allow direct comparison. Furthermore, the activity of a specific protein kinase has not yet been correlated to steps in the hepadnaviral life cycle. In this study we show that capsids from various sources encapsidate active protein kinase Calpha, irrespective of hepatitis B virus genotype and host cell. Treatment of a virion expressing cell line with a pseudosubstrate inhibitor showed that inhibition of protein kinase C phosphorylation did not affect genome maturation but resulted in capsid accumulation and inhibited virion release to the medium. Our results imply that different protein kinases have distinct functions within the hepadnaviral life cycle.

  1. Mechanism of Human Influenza Virus RNA Persistence and Virion Survival in Feces: Mucus Protects Virions From Acid and Digestive Juices.

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    Hirose, Ryohei; Nakaya, Takaaki; Naito, Yuji; Daidoji, Tomo; Watanabe, Yohei; Yasuda, Hiroaki; Konishi, Hideyuki; Itoh, Yoshito

    2017-07-01

    Although viral RNA or infectious virions have been detected in the feces of individuals infected with human influenza A and B viruses (IAV/IBV), the mechanism of viral survival in the gastrointestinal tract remains unclear. We developed a model that attempts to recapitulate the conditions encountered by a swallowed virus. While IAV/IBV are vulnerable to simulated digestive juices (gastric acid and bile/pancreatic juice), highly viscous mucus protects viral RNA and virions, allowing the virus to retain its infectivity. Our results suggest that virions and RNA present in swallowed mucus are not inactivated or degraded by the gastrointestinal environment, allowing their detection in feces. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

  2. Virion-targeted viral inactivation: new therapy against viral infection.

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    Okui, N; Kitamura, Y; Kobayashi, N; Sakuma, R; Ishikawa, T; Kitamura, T

    2001-01-01

    Acquired immune deficiency syndrome (AIDS) is resistant to all current therapy. Gene therapy is an attractive alternative or additive to current, unsatisfactory AIDS therapy. To develop an antiviral molecule targeting viral integrase (HIV IN), we generated a single-chain antibody, termed scAb, which interacted with human immunodeficiency virus type 1 (HIV-1) IN and inhibited virus replication at the integration step when expressed intracellularly. To reduce infectivity from within the virus particles, we made expression plasmids (pC-scAbE-Vpr, pC-scAbE-CA, and pC-scAbE-WXXF), which expressed the anti-HIV IN scAb fused to the N-terminus of HIV-1-associated accessory protein R (Vpr), capsid protein (CA), and specific binding motif to Vpr (WXXF), respectively. All fusion proteins were tagged with a nine-amino acid peptide derived from influenza virus hemagglutinin (HA) at the C terminus. The fusion molecules, termed scAbE-Vpr, scAbE-CA, and scAbE-WXXF, interacted specifically with HIV IN immobilized on a nitrocellulose membrane. Immunoblot analysis showed that scAbE-Vpr, scAbE-CA, and scAbE-WXXF were incorporated into the virions produced by cotransfection of 293T cells with HIV-1 infectious clone DNA (pLAI) and pC-scAbE-Vpr, pC-scAbE-WXXF. A multinuclear activation galactosidase indicator (MAGI) assay revealed that the virions released from 293T cells cotransfected with pLAI and pC-scAbE-Vpr, pC-scAbE-WXXF had as little 1000-fold of the infectivity of the control wild-type virions, which were produced from the 293T cells transfected with pLAI alone. Furthermore, the virions produced from the 293T cells cotransfected with pLAI and an scAb expression vector (pC-scAb) showed only 1% of the infectivity of the control HIV-1 in a MAGI assay, although scAb was not incorporated into the virions. In either instance, the total quantity of the progeny virions released from the transfected 293T cells and the patterns of the virion proteins were hardly affected by the presence of

  3. Effect of host cell lipid metabolism on alphavirus replication, virion morphogenesis, and infectivity.

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    Ng, Ching G; Coppens, Isabelle; Govindarajan, Dhanasekaran; Pisciotta, John; Shulaev, Vladimir; Griffin, Diane E

    2008-10-21

    The alphavirus Sindbis virus (SINV) causes encephalomyelitis in mice. Lipid-containing membranes, particularly cholesterol and sphingomyelin (SM), play important roles in virus entry, RNA replication, glycoprotein transport, and budding. Levels of SM are regulated by sphingomyelinases (SMases). Acid SMase (ASMase) deficiency results in the lipid storage disease type A Niemann-Pick disease (NPD-A), mimicked in mice by interruption of the ASMase gene. We previously demonstrated that ASMase-deficient mice are more susceptible to fatal SINV encephalomyelitis, with increased viral replication, spread, and neuronal death. To determine the mechanisms by which ASMase deficiency enhances SINV replication, we compared NPD-A fibroblasts (NPAF) to normal human fibroblasts (NHF). NPAF accumulated cholesterol- and sphingolipid-rich late endosomes/lysosomes in the perinuclear region. SINV replication was faster and reached higher titer in NPAF than in NHF, and NPAF died more quickly. SINV RNA and protein synthesis was greater in NHF than in NPAF, but virions budding from NPAF were 26 times more infectious and were regular dense particles whereas virions from NHF were larger particles containing substantial amounts of CD63. Cellular regulation of alphavirus morphogenesis is a previously unrecognized mechanism for control of virus replication and spread.

  4. An Ensemble Method to Distinguish Bacteriophage Virion from Non-Virion Proteins Based on Protein Sequence Characteristics

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    Lina Zhang

    2015-09-01

    Full Text Available Bacteriophage virion proteins and non-virion proteins have distinct functions in biological processes, such as specificity determination for host bacteria, bacteriophage replication and transcription. Accurate identification of bacteriophage virion proteins from bacteriophage protein sequences is significant to understand the complex virulence mechanism in host bacteria and the influence of bacteriophages on the development of antibacterial drugs. In this study, an ensemble method for bacteriophage virion protein prediction from bacteriophage protein sequences is put forward with hybrid feature spaces incorporating CTD (composition, transition and distribution, bi-profile Bayes, PseAAC (pseudo-amino acid composition and PSSM (position-specific scoring matrix. When performing on the training dataset 10-fold cross-validation, the presented method achieves a satisfactory prediction result with a sensitivity of 0.870, a specificity of 0.830, an accuracy of 0.850 and Matthew’s correlation coefficient (MCC of 0.701, respectively. To evaluate the prediction performance objectively, an independent testing dataset is used to evaluate the proposed method. Encouragingly, our proposed method performs better than previous studies with a sensitivity of 0.853, a specificity of 0.815, an accuracy of 0.831 and MCC of 0.662 on the independent testing dataset. These results suggest that the proposed method can be a potential candidate for bacteriophage virion protein prediction, which may provide a useful tool to find novel antibacterial drugs and to understand the relationship between bacteriophage and host bacteria. For the convenience of the vast majority of experimental Int. J. Mol. Sci. 2015, 16 21735 scientists, a user-friendly and publicly-accessible web-server for the proposed ensemble method is established.

  5. Egress of budded virions of Autographa californica nucleopolyhedrovirus does not require activity of Spodoptera frugiperda HSP/HSC70 chaperones.

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    Lyupina, Yulia V; Orlova, Olga V; Abaturova, Svetlana B; Beljelarskaya, Svetlana N; Lavrov, Andrey N; Mikhailov, Victor S

    2014-11-04

    The induction of heat shock proteins in baculovirus infected cells is well documented. However a role of these chaperones in infection cycle remains unknown. The observation that HSP70s are associated with virions of different baculoviruses reported by several researchers suggests that HSPs might be structural components of viruses or involved in virion assembly. These hypotheses were examined by using a novel inhibitor of the ATPase and chaperoning activity of HSP/HSC70s, VER-155008. When VER-155008 was added early in infection, the synthesis of viral proteins, genome replication and the production of budded virions (BV) were markedly inhibited indicating the dependence of virus reproduction on host chaperones. However, BV production was unaffected when VER-155008 was added in the mid-replication phase which is after accumulation of products required for completion of the viral DNA replication. These results suggest that the final stages in assembly of BV and their egress from cells do not depend on chaperone activity of host HSP/HSC70s.

  6. Herpes simplex virus VP16 rescues viral mRNA from destruction by the virion host shutoff function.

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    Lam, Q; Smibert, C A; Koop, K E; Lavery, C; Capone, J P; Weinheimer, S P; Smiley, J R

    1996-05-15

    Herpes simplex virus (HSV) virions contain two regulatory proteins that facilitate the onset of the lytic cycle: VP16 activates transcription of the viral immediate-early genes, and vhs triggers shutoff of host protein synthesis and accelerated turnover of cellular and viral mRNAs. VP16 and vhs form a complex in infected cells, raising the possibility of a regulatory link between them. Here we show that viral protein synthesis and mRNA levels undergo a severe decline at intermediate times after infection with a VP16 null mutant, culminating in virtually complete translational arrest. This phenotype was rescued by a transcriptionally incompetent derivative of VP16 that retains vhs binding activity, and was eliminated by inactivating the vhs gene. These results indicate that VP16 dampens vhs activity, allowing HSV mRNAs to persist in infected cells. Further evidence supporting this hypothesis came from the demonstration that a stably transfected cell line expressing VP16 was resistant to host shutoff induced by superinfecting HSV virions. Thus, in addition to its well known function as a transcriptional activator, VP16 stimulates viral gene expression at a post-transcriptional level, by sparing viral mRNAs from degradation by one of the virus-induced host shutoff mechanisms.

  7. Fine structure of the vaccinia virion determined by controlled degradation and immunolocalization

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    Moussatche, Nissin, E-mail: nissin@ufl.edu; Condit, Richard C.

    2015-01-15

    The vaccinia virion is a membraned, slightly flattened, barrel-shaped particle, with a complex internal structure featuring a biconcave core flanked by lateral bodies. Although the architecture of the purified mature virion has been intensely characterized by electron microscopy, the distribution of the proteins within the virion has been examined primarily using biochemical procedures. Thus, it has been shown that non-ionic and ionic detergents combined or not with a sulfhydryl reagent can be used to disrupt virions and, to a limited degree, separate the constituent proteins in different fractions. Applying a controlled degradation technique to virions adsorbed on EM grids, we were able to immuno-localize viral proteins within the virion particle. Our results show after NP40 and DTT treatment, membrane proteins are removed from the virion surface revealing proteins that are associated with the lateral bodies and the outer layer of the core wall. Combined treatment using high salt and high DTT removed lateral body proteins and exposed proteins of the internal core wall. Cores treated with proteases could be disrupted and the internal components were exposed. Cts8, a mutant in the A3 protein, produces aberrant virus that, when treated with NP-40 and DTT, releases to the exterior the virus DNA associated with other internal core proteins. With these results, we are able to propose a model for the structure the vaccinia virion.

  8. Quantitative real-time single particle analysis of virions.

    Science.gov (United States)

    Heider, Susanne; Metzner, Christoph

    2014-08-01

    Providing information about single virus particles has for a long time been mainly the domain of electron microscopy. More recently, technologies have been developed-or adapted from other fields, such as nanotechnology-to allow for the real-time quantification of physical virion particles, while supplying additional information such as particle diameter concomitantly. These technologies have progressed to the stage of commercialization increasing the speed of viral titer measurements from hours to minutes, thus providing a significant advantage for many aspects of virology research and biotechnology applications. Additional advantages lie in the broad spectrum of virus species that may be measured and the possibility to determine the ratio of infectious to total particles. A series of disadvantages remain associated with these technologies, such as a low specificity for viral particles. In this review we will discuss these technologies by comparing four systems for real-time single virus particle analysis and quantification.

  9. Capillarity-induced disassembly of virions in carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Fan Xiaobin; Peng Wenchao; Li Yang; Li Xianyu; Zhang Guoliang; Zhang Fengbao [School of Chemical Engineering and Technology, Tianjin University, Tianjin (China); Barclay, J Elaine; Evans, David J [Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH (United Kingdom)], E-mail: fbzhang@tju.edu.cn

    2008-04-23

    Studying the transport and fate of viruses through nanochannels is of great importance. By using the nanochannel of a carbon nanotube (CNT) as an ideal model, we evaluated the possibility of capillarity-induced viral transport through a closely fitting nanochannel and explored the mechanisms involved. It is shown both experimentally and theoretically that Cowpea mosaic virus can enter CNTs by capillarity. However, when introduced into a nanotube the protein capsid may disassemble. During the initial capillary filling stage, anomalous needle-shaped high pressure exists in the centre of the nanotube's entrance. This high pressure, combining with the significant negative pressure within the nanotube, may account for the disassembly of the virions.

  10. Replication of Bovine Papillomavirus Type 1 (BPV-1) DNA in Saccharomyces cerevisiae following Infection with BPV-1 Virions

    OpenAIRE

    Zhao, Kong-Nan; Frazer, Ian H

    2002-01-01

    Saccharomyces cerevisiae protoplasts exposed to bovine papillomavirus type 1 (BPV-1) virions demonstrated uptake of virions on electron microscopy. S. cerevisiae cells looked larger after exposure to BPV-1 virions, and cell wall regeneration was delayed. Southern blot hybridization of Hirt DNA from cells exposed to BPV-1 virions demonstrated BPV-1 DNA, which could be detected over 80 days of culture and at least 13 rounds of division. Two-dimensional gel analysis of Hirt DNA showed replicativ...

  11. The vaccinia virus E6 protein influences virion protein localization during virus assembly

    Energy Technology Data Exchange (ETDEWEB)

    Condit, Richard C., E-mail: condit@mgm.ufl.edu; Moussatche, Nissin

    2015-08-15

    Vaccinia virus mutants in which expression of the virion core protein gene E6R is repressed are defective in virion morphogenesis. E6 deficient infections fail to properly package viroplasm into viral membranes, resulting in an accumulation of empty immature virions and large aggregates of viroplasm. We have used immunogold electron microscopy and immunofluorescence confocal microscopy to assess the intracellular localization of several virion structural proteins and enzymes during E6R mutant infections. We find that during E6R mutant infections virion membrane proteins and virion transcription enzymes maintain a normal localization within viral factories while several major core and lateral body proteins accumulate in aggregated virosomes. The results support a model in which vaccinia virions are assembled from at least three substructures, the membrane, the viroplasm and a “pre-nucleocapsid”, and that the E6 protein is essential for maintaining proper localization of the seven-protein complex and the viroplasm during assembly. - Highlights: • Mutation of E6 disrupts association of viral membranes with viral core proteins • Mutation of E6 does not perturb viral membrane biosynthesis • Mutation of E6 does not perturb localization of viral transcription enzymes • Mutation of E6 causes mis-localization and aggregation of viral core proteins • Vaccinia assembly uses three subassemblies: membranes, viroplasm, prenucleocapsid.

  12. Identification of bacteriophage virion proteins by the ANOVA feature selection and analysis.

    Science.gov (United States)

    Ding, Hui; Feng, Peng-Mian; Chen, Wei; Lin, Hao

    2014-08-01

    The bacteriophage virion proteins play extremely important roles in the fate of host bacterial cells. Accurate identification of bacteriophage virion proteins is very important for understanding their functions and clarifying the lysis mechanism of bacterial cells. In this study, a new sequence-based method was developed to identify phage virion proteins. In the new method, the protein sequences were initially formulated by the g-gap dipeptide compositions. Subsequently, the analysis of variance (ANOVA) with incremental feature selection (IFS) was used to search for the optimal feature set. It was observed that, in jackknife cross-validation, the optimal feature set including 160 optimized features can produce the maximum accuracy of 85.02%. By performing feature analysis, we found that the correlation between two amino acids with one gap was more important than other correlations for phage virion protein prediction and that some of the 1-gap dipeptides were important and mainly contributed to the virion protein prediction. This analysis will provide novel insights into the function of phage virion proteins. On the basis of the proposed method, an online web-server, PVPred, was established and can be freely accessed from the website (http://lin.uestc.edu.cn/server/PVPred). We believe that the PVPred will become a powerful tool to study phage virion proteins and to guide the related experimental validations.

  13. The 5' cap of tobacco mosaic virus (TMV) is required for virion attachment to the actin/endoplasmic reticulum network during early infection.

    Science.gov (United States)

    Christensen, Nynne; Tilsner, Jens; Bell, Karen; Hammann, Philippe; Parton, Richard; Lacomme, Christophe; Oparka, Karl

    2009-05-01

    Almost nothing is known of the earliest stages of plant virus infections. To address this, we microinjected Cy3 (UTP)-labelled tobacco mosaic virus (TMV) into living tobacco trichome cells. The Cy3-virions were infectious, and the viral genome trafficked from cell to cell. However, neither the fluorescent vRNA pool nor the co-injected green fluorescent protein (GFP) left the injected trichome, indicating that the synthesis of (unlabelled) progeny viral (v)RNA is required to initiate cell-to-cell movement, and that virus movement is not accompanied by passive plasmodesmatal gating. Cy3-vRNA formed granules that became anchored to the motile cortical actin/endoplasmic reticulum (ER) network within minutes of injection. Granule movement on actin/ER was arrested by actin inhibitors indicating actin-dependent RNA movement. The 5' methylguanosine cap was shown to be required for vRNA anchoring to the actin/ER. TMV vRNA lacking the 5' cap failed to form granules and was degraded in the cytoplasm. Removal of the 3' untranslated region or replicase both inhibited replication but did not prevent granule formation and movement. Dual-labelled TMV virions in which the vRNA and the coat protein were highlighted with different fluorophores showed that both fluorescent signals were initially located on the same ER-bound granules, indicating that TMV virions may become attached to the ER prior to uncoating of the viral genome.

  14. Architects of assembly: roles of Flaviviridae non-structural proteins in virion morphogenesis.

    Science.gov (United States)

    Murray, Catherine L; Jones, Christopher T; Rice, Charles M

    2008-09-01

    Viruses of the Flaviviridae family, including hepatitis C, dengue and bovine viral diarrhoea, are responsible for considerable morbidity and mortality worldwide. Recent advances in our understanding of virion assembly have uncovered commonalities among distantly related members of this family. We discuss the emerging hypothesis that physical virion components are not alone in forming the infectious particle, but that non-structural proteins are intimately involved in orchestrating morphogenesis. Pinpointing the roles of Flaviviridae proteins in virion production could reveal new avenues for antiviral therapeutics.

  15. Mutational analysis of the herpes simplex virus virion host shutoff protein: evidence that vhs functions in the absence of other viral proteins.

    Science.gov (United States)

    Jones, F E; Smibert, C A; Smiley, J R

    1995-08-01

    Herpes simplex virus (HSV) virions contain one or more factors that trigger rapid shutoff of host protein synthesis and accelerated decay of cellular and viral mRNAs in infected cells. HSV isolates bearing mutations at the virion host shutoff (vhs) locus (gene UL41) are defective for both processes, indicating that the vhs protein is required; however, it is not clear whether the role of vhs in shutoff is direct or indirect and if other virion components are also necessary. We therefore used a transient-cotransfection assay to determine if the vhs protein displays activity in the absence of other viral gene products. We found that a vhs expression vector strongly suppressed expression of a cotransfected lacZ reporter gene and that this effect was eliminated by the vhs1 point mutation that abolishes virion-induced host shutoff during HSV infection. Further evidence for the biological relevance of the transfection assay came from the demonstration that five vhs in-frame linker insertion mutations yielded concordant results when assayed in cotransfected cells and following transfer into the viral genome: three mutations eliminated activity in both assays, while two had no effect. On the basis of these results, we conclude that the vhs protein can trigger host shutoff in the absence of other HSV proteins. The cotransfection assay was used to rapidly assess the activities of a panel of linker insertion mutants spanning the vhs polypeptide. All mutations that mapped to regions conserved among the vhs homologs of alphaherpesvirus inactivated function; in contrast, four of five mutations that mapped to regions that are absent from several vhs homologs had no effect. These results further support the biological relevance of the transfection assay and begin to delineate functional domains of the vhs polypeptide.

  16. Mapping the small RNA content of simian immunodeficiency virions (SIV.

    Directory of Open Access Journals (Sweden)

    Markus Brameier

    Full Text Available Recent evidence indicates that regulatory small non-coding RNAs are not only components of eukaryotic cells and vesicles, but also reside within a number of different viruses including retroviral particles. Using ultra-deep sequencing we have comprehensively analyzed the content of simian immunodeficiency virions (SIV, which were compared to mock-control preparations. Our analysis revealed that more than 428,000 sequence reads matched the SIV mac239 genome sequence. Among these we could identify 12 virus-derived small RNAs (vsRNAs that were highly abundant. Beside known retrovirus-enriched small RNAs, like 7SL-RNA, tRNA(Lys3 and tRNA(Lys isoacceptors, we also identified defined fragments derived from small ILF3/NF90-associated RNA snaR-A14, that were enriched more than 50 fold in SIV. We also found evidence that small nucleolar RNAs U2 and U12 were underrepresented in the SIV preparation, indicating that the relative number or the content of co-isolated exosomes was changed upon infection. Our comprehensive atlas of SIV-incorporated small RNAs provides a refined picture of the composition of retrovirions, which gives novel insights into viral packaging.

  17. Packageable antiviral therapeutics against human immunodeficiency virus type 1: virion-targeted virus inactivation by incorporation of a single-chain antibody against viral integrase into progeny virions.

    Science.gov (United States)

    Okui, N; Sakuma, R; Kobayashi, N; Yoshikura, H; Kitamura, T; Chiba, J; Kitamura, Y

    2000-03-01

    To determine their activities as an antiviral agent packageable within virions and suitable for continued expression in cells, we tested a single-chain antibody (scAb) against human immunodeficiency virus type 1 (HIV-1) integrase and its three fusion proteins: fused to viral protein R (scab-Vpr), a double-cassette of the WXXF motif binding to Vpr (scAb-WXXF), and viral major capsid protein (scAb-CA), respectively. Cotransfection of human 293T cells with expression plasmid for scAb-Vpr or -WXXF along with HIV-1 clone pLAI resulted in the production of a normal amount of progeny virions with infectivity decreased by more than 10(3)-fold. Immunoblot analyses showed that scAb-Vpr or -WXXF was associated with virions, whereas scAb or scAb-CA was not, suggesting that scAb-Vpr or -WXXF was incorporated into virions. The incorporation of scAb-WXXF appeared to be Vpr dependent, because the fusion protein was associated with the wild-type but not with Vpr-truncated HIV-1 virions. Since G418-selected HeLa clones carrying expression plasmid for scAb-WXXF were obtained much more frequently than those for scAb-Vpr, scAb-WXXF was inferred to be less toxic to cells than scAb-Vpr. These results suggest that scAb-WXXF may serve as a novel class of antiviral therapeutic that inactivates progeny HIV virions from within.

  18. Endophilins interact with Moloney murine leukemia virus Gag and modulate virion production

    Directory of Open Access Journals (Sweden)

    De Camilli Pietro

    2003-12-01

    Full Text Available Abstract Background The retroviral Gag protein is the central player in the process of virion assembly at the plasma membrane, and is sufficient to induce the formation and release of virus-like particles. Recent evidence suggests that Gag may co-opt the host cell's endocytic machinery to facilitate retroviral assembly and release. Results A search for novel partners interacting with the Gag protein of the Moloney murine leukemia virus (Mo-MuLV via the yeast two-hybrid protein-protein interaction assay resulted in the identification of endophilin 2, a component of the machinery involved in clathrin-mediated endocytosis. We demonstrate that endophilin interacts with the matrix or MA domain of the Gag protein of Mo-MuLV, but not of human immunodeficiency virus, HIV. Both exogenously expressed and endogenous endophilin are incorporated into Mo-MuLV viral particles. Titration experiments suggest that the binding sites for inclusion of endophilin into viral particles are limited and saturable. Knock-down of endophilin with small interfering RNA (siRNA had no effect on virion production, but overexpression of endophilin and, to a lesser extent, of several fragments of the protein, result in inhibition of Mo-MuLV virion production, but not of HIV virion production. Conclusions This study shows that endophilins interact with Mo-MuLV Gag and affect virion production. The findings imply that endophilin is another component of the large complex that is hijacked by retroviruses to promote virion production.

  19. The choreography of HIV-1 proteolytic processing and virion assembly.

    Science.gov (United States)

    Lee, Sook-Kyung; Potempa, Marc; Swanstrom, Ronald

    2012-11-30

    HIV-1 has been the target of intensive research at the molecular and biochemical levels for >25 years. Collectively, this work has led to a detailed understanding of viral replication and the development of 24 approved drugs that have five different targets on various viral proteins and one cellular target (CCR5). Although most drugs target viral enzymatic activities, our detailed knowledge of so much of the viral life cycle is leading us into other types of inhibitors that can block or disrupt protein-protein interactions. Viruses have compact genomes and employ a strategy of using a small number of proteins that can form repeating structures to enclose space (i.e. condensing the viral genome inside of a protein shell), thus minimizing the need for a large protein coding capacity. This creates a relatively small number of critical protein-protein interactions that are essential for viral replication. For HIV-1, the Gag protein has the role of a polyprotein precursor that contains all of the structural proteins of the virion: matrix, capsid, spacer peptide 1, nucleocapsid, spacer peptide 2, and p6 (which contains protein-binding domains that interact with host proteins during budding). Similarly, the Gag-Pro-Pol precursor encodes most of the Gag protein but now includes the viral enzymes: protease, reverse transcriptase (with its associated RNase H activity), and integrase. Gag and Gag-Pro-Pol are the substrates of the viral protease, which is responsible for cleaving these precursors into their mature and fully active forms (see Fig. 1A).

  20. Herpes simplex virus virion host shutoff (vhs) activity alters periocular disease in mice.

    Science.gov (United States)

    Smith, T J; Ackland-Berglund, C E; Leib, D A

    2000-04-01

    During lytic infection, the virion host shutoff (vhs) protein of herpes simplex virus (HSV) mediates the rapid degradation of RNA and shutoff of host protein synthesis. In mice, HSV type 1 (HSV-1) mutants lacking vhs activity are profoundly attenuated. HSV-2 has significantly higher vhs activity than HSV-1, eliciting a faster and more complete shutoff. To examine further the role of vhs activity in pathogenesis, we generated an intertypic recombinant virus (KOSV2) in which the vhs open reading frame of HSV-1 strain KOS was replaced with that of HSV-2 strain 333. KOSV2 and a marker-rescued virus, KOSV2R, were characterized in cell culture and tested in an in vivo mouse eye model of latency and pathogenesis. The RNA degradation kinetics of KOSV2 was identical to that of HSV-2 333, and both showed vhs activity significantly higher than that of KOS. This demonstrated that the fast vhs-mediated degradation phenotype of 333 had been conferred upon KOS. The growth of KOSV2 was comparable to that of KOS, 333, and KOSV2R in cell culture, murine corneas, and trigeminal ganglia and had a reactivation frequency similar to those of KOS and KOSV2R from explanted latently infected trigeminal ganglia. There was, however, significantly reduced blepharitis and viral replication within the periocular skin of KOSV2-infected mice compared to mice infected with either KOS or KOSV2R. Taken together, these data demonstrate that heightened vhs activity, in the context of HSV-1 infection, leads to increased viral clearance from the skin of mice and that the replication of virus in the skin is a determining factor for blepharitis. These data also suggest a role for vhs in modulating host responses to HSV infection.

  1. Pathogenesis of herpes simplex virus type 2 virion host shutoff (vhs) mutants.

    Science.gov (United States)

    Smith, Tracy J; Morrison, Lynda A; Leib, David A

    2002-03-01

    During lytic infection, the virion host shutoff (vhs) protein mediates the rapid degradation of mRNA and the shutoff of host protein synthesis. In vivo, herpes simplex virus type 1 (HSV-1) mutants lacking vhs activity are profoundly attenuated. Homologs of vhs exist in all of the neurotropic herpesviruses, and the goal of this study was to determine the virulence of HSV-2 mutants lacking vhs. Two HSV-2 recombinants were used in this study: 333-vhsB, which has a lacZ cassette inserted into the N terminus of vhs, and 333d41, which has a 939-bp deletion in vhs. As expected, both 333-vhsB and 333d41 failed to induce the cellular RNA degradation characteristic of HSV. Corneal, vaginal, and intracerebral routes of infection were used to study pathogenesis. Both viruses grew to significantly lower titers in the corneas, trigeminal ganglia, vaginas, dorsal root ganglia, spinal cords, and brains of mice than wild-type and rescue viruses, with a correspondingly reduced induction of disease. Both viruses, however, reactivated efficiently from explanted trigeminal ganglia, showing that vhs is dispensable for reactivation. The lethality of 333d41 following peripheral infection of mice, however, was significantly higher than that of 333-vhsB, suggesting that some of the attenuation of 333-vhsB may be due to the presence of a lacZ cassette in the vhs locus. Taken together, these data show that vhs represents an important determinant of HSV-2 pathogenesis and have implications for the design of HSV-2 recombinants and vaccines.

  2. Properties of virion transactivator proteins encoded by primate cytomegaloviruses

    Directory of Open Access Journals (Sweden)

    Barry Peter A

    2009-05-01

    Full Text Available Abstract Background Human cytomegalovirus (HCMV is a betaherpesvirus that causes severe disease in situations where the immune system is immature or compromised. HCMV immediate early (IE gene expression is stimulated by the virion phosphoprotein pp71, encoded by open reading frame (ORF UL82, and this transactivation activity is important for the efficient initiation of viral replication. It is currently recognized that pp71 acts to overcome cellular intrinsic defences that otherwise block viral IE gene expression, and that interactions of pp71 with the cell proteins Daxx and ATRX are important for this function. A further property of pp71 is the ability to enable prolonged gene expression from quiescent herpes simplex virus type 1 (HSV-1 genomes. Non-human primate cytomegaloviruses encode homologs of pp71, but there is currently no published information that addresses their effects on gene expression and modes of action. Results The UL82 homolog encoded by simian cytomegalovirus (SCMV, strain Colburn, was identified and cloned. This ORF, named S82, was cloned into an HSV-1 vector, as were those from baboon, rhesus monkey and chimpanzee cytomegaloviruses. The use of an HSV-1 vector enabled expression of the UL82 homologs in a range of cell types, and permitted investigation of their abilities to direct prolonged gene expression from quiescent genomes. The results show that all UL82 homologs activate gene expression, and that neither host cell type nor promoter target sequence has major effects on these activities. Surprisingly, the UL82 proteins specified by non-human primate cytomegaloviruses, unlike pp71, did not direct long term expression from quiescent HSV-1 genomes. In addition, significant differences were observed in the intranuclear localization of the UL82 homologs, and in their effects on Daxx. Strikingly, S82 mediated the release of Daxx from nuclear domain 10 substructures much more rapidly than pp71 or the other proteins tested. All

  3. RAB1A promotes Vaccinia virus replication by facilitating the production of intracellular enveloped virions

    Energy Technology Data Exchange (ETDEWEB)

    Pechenick Jowers, Tali; Featherstone, Rebecca J.; Reynolds, Danielle K.; Brown, Helen K. [The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, Midlothian EH25 9RG, Scotland (United Kingdom); James, John; Prescott, Alan [Division of Cell Signalling and Immunology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland (United Kingdom); Haga, Ismar R. [The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, Midlothian EH25 9RG, Scotland (United Kingdom); Beard, Philippa M., E-mail: pip.beard@roslin.ed.ac.uk [The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, Midlothian EH25 9RG, Scotland (United Kingdom)

    2015-01-15

    Vaccinia virus (VACV) is a large double-stranded DNA virus with a complex cytoplasmic replication cycle that exploits numerous cellular proteins. This work characterises the role of a proviral cellular protein, the small GTPase RAB1A, in VACV replication. Using siRNA, we identified RAB1A as required for the production of extracellular enveloped virions (EEVs), but not intracellular mature virions (IMVs). Immunofluorescence and electron microscopy further refined the role of RAB1A as facilitating the wrapping of IMVs to become intracellular enveloped virions (IEVs). This is consistent with the known function of RAB1A in maintenance of ER to Golgi transport. VACV can therefore be added to the growing list of viruses which require RAB1A for optimal replication, highlighting this protein as a broadly proviral host factor. - Highlights: • Characterisation of the role of the small GTPase RAB1A in VACV replication. • RAB1A is not required for production of the primary virion form (IMV). • RAB1A is required for production of processed virion forms (IEVs, CEVs and EEVs). • Consistent with known role of RAB1A in ER to Golgi transport.

  4. Mixed genotype transmission bodies and virions contribute to the maintenance of diversity in an insect virus

    Science.gov (United States)

    Clavijo, Gabriel; Williams, Trevor; Muñoz, Delia; Caballero, Primitivo; López-Ferber, Miguel

    2010-01-01

    An insect nucleopolyhedrovirus naturally survives as a mixture of at least nine genotypes. Infection by multiple genotypes results in the production of virus occlusion bodies (OBs) with greater pathogenicity than those of any genotype alone. We tested the hypothesis that each OB contains a genotypically diverse population of virions. Few insects died following inoculation with an experimental two-genotype mixture at a dose of one OB per insect, but a high proportion of multiple infections were observed (50%), which differed significantly from the frequencies predicted by a non-associated transmission model in which genotypes are segregated into distinct OBs. By contrast, insects that consumed multiple OBs experienced higher mortality and infection frequencies did not differ significantly from those of the non-associated model. Inoculation with genotypically complex wild-type OBs indicated that genotypes tend to be transmitted in association, rather than as independent entities, irrespective of dose. To examine the hypothesis that virions may themselves be genotypically heterogeneous, cell culture plaques derived from individual virions were analysed to reveal that one-third of virions was of mixed genotype, irrespective of the genotypic composition of the OBs. We conclude that co-occlusion of genotypically distinct virions in each OB is an adaptive mechanism that favours the maintenance of virus diversity during insect-to-insect transmission. PMID:19939845

  5. Purification of infectious human herpesvirus 6A virions and association of host cell proteins

    Directory of Open Access Journals (Sweden)

    Garoff Henrik

    2007-10-01

    Full Text Available Abstract Background Viruses that are incorporating host cell proteins might trigger autoimmune diseases. It is therefore of interest to identify possible host proteins associated with viruses, especially for enveloped viruses that have been suggested to play a role in autoimmune diseases, like human herpesvirus 6A (HHV-6A in multiple sclerosis (MS. Results We have established a method for rapid and morphology preserving purification of HHV-6A virions, which in combination with parallel analyses with background control material released from mock-infected cells facilitates qualitative and quantitative investigations of the protein content of HHV-6A virions. In our iodixanol gradient purified preparation, we detected high levels of viral DNA by real-time PCR and viral proteins by metabolic labelling, silver staining and western blots. In contrast, the background level of cellular contamination was low in the purified samples as demonstrated by the silver staining and metabolic labelling analyses. Western blot analyses showed that the cellular complement protein CD46, the receptor for HHV-6A, is associated with the purified and infectious virions. Also, the cellular proteins clathrin, ezrin and Tsg101 are associated with intact HHV-6A virions. Conclusion Cellular proteins are associated with HHV-6A virions. The relevance of the association in disease and especially in autoimmunity will be further investigated.

  6. Palmitoylations on murine coronavirus spike proteins are essential for virion assembly and infectivity.

    Science.gov (United States)

    Thorp, Edward B; Boscarino, Joseph A; Logan, Hillary L; Goletz, Jeffrey T; Gallagher, Thomas M

    2006-02-01

    Coronavirus spike (S) proteins are palmitoylated at several cysteine residues clustered near their transmembrane-spanning domains. This is achieved by cellular palmitoyl acyltransferases (PATs), which can modify newly synthesized S proteins before they are assembled into virion envelopes at the intermediate compartment of the exocytic pathway. To address the importance of these fatty acylations to coronavirus infection, we exposed infected cells to 2-bromopalmitate (2-BP), a specific PAT inhibitor. 2-BP profoundly reduced the specific infectivities of murine coronaviruses at very low, nontoxic doses that were inert to alphavirus and rhabdovirus infections. 2-BP effected only two- to fivefold reductions in S palmitoylation, yet this correlated with reduced S complexing with virion membrane (M) proteins and consequent exclusion of S from virions. At defined 2-BP doses, underpalmitoylated S proteins instead trafficked to infected cell surfaces and elicited cell-cell membrane fusions, suggesting that the acyl chain adducts are more critical to virion assembly than to S-induced syncytial developments. These studies involving pharmacologic inhibition of S protein palmitoylation were complemented with molecular genetic analyses in which cysteine acylation substrates were mutated. Notably, some mutations (C1347F and C1348S) did not interfere with S incorporation into virions, indicating that only a subset of the cysteine-rich region provides the essential S-assembly functions. However, the C1347F/C1348S mutant viruses exhibited relatively low specific infectivities, similar to virions secreted from 2-BP-treated cultures. Our collective results indicate that the palmitate adducts on coronavirus S proteins are necessary in assembly and also in positioning the assembled envelope proteins for maximal infectivity.

  7. Complexes assembled from TMV-derived spherical particles and entire virions of heterogeneous nature.

    Science.gov (United States)

    Trifonova, Ekaterina; Nikitin, Nikolai; Gmyl, Anatoly; Lazareva, Ekaterina; Karpova, Olga; Atabekov, Joseph

    2014-01-01

    Previously, we described some structural features of spherical particles (SPs) generated by thermal remodelling of the tobacco mosaic virus. The SPs represent a universal platform that could bind various proteins. Here, we report that entire isometric virions of heterogeneous nature bind non-specifically to the SPs. Formaldehyde (FA) was used for covalent binding of a virus to the SPs surface for stabilizing the SP-virus complexes. Transmission and high resolution scanning electron microscopy showed that the SPs surface was covered with virus particles. The architecture of SP-virion complexes was examined by immunologic methods. Mean diameters of SPs and SP-human enterovirus C and SP-cauliflower mosaic virus (CaMV) compositions were determined by nanoparticle tracking analysis (NTA) in liquid. Significantly, neither free SPs nor individual virions were detected by NTA in either FA-crosslinked or FA-untreated compositions. Entirely, all virions were bound to the SPs surface and the SP sites within the SP-CaMV complexes were inaccessible for anti-SP antibodies. Likewise, the SPs immunogenicity within the FA-treated SPs-CaMV compositions was negligible. Apparently, the SP antigenic sites were hidden and masked by virions within the compositions. Previously, we reported that the SPs exhibited adjuvant activity when foreign proteins/epitopes were mixed with or crosslinked to SPs. We found that immunogenicity of entire CaMV crosslinked to SP was rather low which could be due to the above-mentioned masking of the SPs booster. Contrastingly, immunogenicity of the FA-untreated compositions increased significantly, presumably, due to partial release of virions and unmasking of some SPs-buster sites after animals immunization.

  8. Vaccinia virus virion membrane biogenesis protein A11 associates with viral membranes in a manner that requires the expression of another membrane biogenesis protein, A6.

    Science.gov (United States)

    Wu, Xiang; Meng, Xiangzhi; Yan, Bo; Rose, Lloyd; Deng, Junpeng; Xiang, Yan

    2012-10-01

    A group of vaccinia virus (VACV) proteins, including A11, L2, and A6, are required for biogenesis of the primary envelope of VACV, specifically, for the acquisition of viral membrane precursors. However, the interconnection among these proteins is unknown and, with the exception of L2, the connection of these proteins with membranes is also unknown. In this study, prompted by the findings that A6 coprecipitated A11 and that the cellular distribution of A11 was dramatically altered by repression of A6 expression, we studied the localization of A11 in cells by using immunofluorescence and cell fractionation analysis. A11 was found to associate with membranes and colocalize with virion membrane proteins in viral replication factories during normal VACV replication. A11 partitioned almost equally between the detergent and aqueous phases upon Triton X-114 phase separation, demonstrating an intrinsic affinity with lipids. However, in the absence of infection or VACV late protein synthesis, A11 did not associate with cellular membranes. Furthermore, when A6 expression was repressed, A11 did not colocalize with any viral membrane proteins or associate with membranes. In contrast, when virion envelope formation was blocked at a later step by repression of A14 expression or by rifampin treatment, A11 colocalized with virion membrane proteins in the factories. Altogether, our data showed that A11 associates with viral membranes during VACV replication, and this association requires A6 expression. This study provides a physical connection between A11 and viral membranes and suggests that A6 regulates A11 membrane association.

  9. Imaging real-time HIV-1 virion fusion with FRET-based biosensors

    Science.gov (United States)

    Jones, Daniel M.; Padilla-Parra, Sergi

    2015-01-01

    We have produced a novel, simple and rapid method utilising genetically encodable FRET-based biosensors to permit the detection of HIV-1 virion fusion in living cells. These biosensors show high sensitivity both spatially and temporally, and allow the real-time recovery of HIV-1 fusion kinetics in both single cells and cell populations simultaneously. PMID:26300212

  10. Kinetics of proton transport into influenza virions by the viral M2 channel.

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    Tijana Ivanovic

    Full Text Available M2 protein of influenza A viruses is a tetrameric transmembrane proton channel, which has essential functions both early and late in the virus infectious cycle. Previous studies of proton transport by M2 have been limited to measurements outside the context of the virus particle. We have developed an in vitro fluorescence-based assay to monitor internal acidification of individual virions triggered to undergo membrane fusion. We show that rimantadine, an inhibitor of M2 proton conductance, blocks the acidification-dependent dissipation of fluorescence from a pH-sensitive virus-content probe. Fusion-pore formation usually follows internal acidification but does not require it. The rate of internal virion acidification increases with external proton concentration and saturates with a pK(m of ∼4.7. The rate of proton transport through a single, fully protonated M2 channel is approximately 100 to 400 protons per second. The saturating proton-concentration dependence and the low rate of internal virion acidification derived from authentic virions support a transporter model for the mechanism of proton transfer.

  11. Functional importance of dengue virus maturation : infectious properties of immature virions

    NARCIS (Netherlands)

    Zybert, Izabela A.; van der Ende-Metselaar, Heidi; Wilschut, Jan; Smit, Jolanda M.

    2008-01-01

    Prior to the release of flavivirus particles from infected cells, the viral surface protein prM is cleaved to M by the cellular enzyme furin. For dengue virus (DENV), this maturation process appears to be very inefficient since a high proportion of progeny virions contain uncleaved prM. Furthermore,

  12. Virion Structure of Black Queen Cell Virus, a Common Honeybee Pathogen

    Science.gov (United States)

    Spurny, Radovan; Přidal, Antonín; Pálková, Lenka; Kiem, Hoa Khanh Tran; de Miranda, Joachim R.

    2017-01-01

    ABSTRACT Viral diseases are a major threat to honeybee (Apis mellifera) populations worldwide and therefore an important factor in reliable crop pollination and food security. Black queen cell virus (BQCV) is the etiological agent of a fatal disease of honeybee queen larvae and pupae. The virus belongs to the genus Triatovirus from the family Dicistroviridae, which is part of the order Picornavirales. Here we present a crystal structure of BQCV determined to a resolution of 3.4 Å. The virion is formed by 60 copies of each of the major capsid proteins VP1, VP2, and VP3; however, there is no density corresponding to a 75-residue-long minor capsid protein VP4 encoded by the BQCV genome. We show that the VP4 subunits are present in the crystallized virions that are infectious. This aspect of the BQCV virion is similar to that of the previously characterized triatoma virus and supports the recent establishment of the separate genus Triatovirus within the family Dicistroviridae. The C terminus of VP1 and CD loops of capsid proteins VP1 and VP3 of BQCV form 34-Å-tall finger-like protrusions at the virion surface. The protrusions are larger than those of related dicistroviruses. IMPORTANCE The western honeybee is the most important pollinator of all, and it is required to sustain the agricultural production and biodiversity of wild flowering plants. However, honeybee populations worldwide are suffering from virus infections that cause colony losses. One of the most common, and least known, honeybee pathogens is black queen cell virus (BQCV), which at high titers causes queen larvae and pupae to turn black and die. Here we present the three-dimensional virion structure of BQCV, determined by X-ray crystallography. The structure of BQCV reveals large protrusions on the virion surface. Capsid protein VP1 of BQCV does not contain a hydrophobic pocket. Therefore, the BQCV virion structure provides evidence that capsid-binding antiviral compounds that can prevent the

  13. Antibody-Mediated Internalization of Infectious HIV-1 Virions Differs among Antibody Isotypes and Subclasses.

    Science.gov (United States)

    Tay, Matthew Zirui; Liu, Pinghuang; Williams, LaTonya D; McRaven, Michael D; Sawant, Sheetal; Gurley, Thaddeus C; Xu, Thomas T; Dennison, S Moses; Liao, Hua-Xin; Chenine, Agnès-Laurence; Alam, S Munir; Moody, M Anthony; Hope, Thomas J; Haynes, Barton F; Tomaras, Georgia D

    2016-08-01

    Emerging data support a role for antibody Fc-mediated antiviral activity in vaccine efficacy and in the control of HIV-1 replication by broadly neutralizing antibodies. Antibody-mediated virus internalization is an Fc-mediated function that may act at the portal of entry whereby effector cells may be triggered by pre-existing antibodies to prevent HIV-1 acquisition. Understanding the capacity of HIV-1 antibodies in mediating internalization of HIV-1 virions by primary monocytes is critical to understanding their full antiviral potency. Antibody isotypes/subclasses differ in functional profile, with consequences for their antiviral activity. For instance, in the RV144 vaccine trial that achieved partial efficacy, Env IgA correlated with increased risk of HIV-1 infection (i.e. decreased vaccine efficacy), whereas V1-V2 IgG3 correlated with decreased risk of HIV-1 infection (i.e. increased vaccine efficacy). Thus, understanding the different functional attributes of HIV-1 specific IgG1, IgG3 and IgA antibodies will help define the mechanisms of immune protection. Here, we utilized an in vitro flow cytometric method utilizing primary monocytes as phagocytes and infectious HIV-1 virions as targets to determine the capacity of Env IgA (IgA1, IgA2), IgG1 and IgG3 antibodies to mediate HIV-1 infectious virion internalization. Importantly, both broadly neutralizing antibodies (i.e. PG9, 2G12, CH31, VRC01 IgG) and non-broadly neutralizing antibodies (i.e. 7B2 mAb, mucosal HIV-1+ IgG) mediated internalization of HIV-1 virions. Furthermore, we found that Env IgG3 of multiple specificities (i.e. CD4bs, V1-V2 and gp41) mediated increased infectious virion internalization over Env IgG1 of the same specificity, while Env IgA mediated decreased infectious virion internalization compared to IgG1. These data demonstrate that antibody-mediated internalization of HIV-1 virions depends on antibody specificity and isotype. Evaluation of the phagocytic potency of vaccine

  14. Electroporation facilitates introduction of reporter transgenes and virions into schistosome eggs.

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    Kristine J Kines

    2010-02-01

    Full Text Available The schistosome egg represents an attractive developmental stage at which to target transgenes because of the high ratio of germ to somatic cells, because the transgene might be propagated and amplified by infecting snails with the miracidia hatched from treated eggs, and because eggs can be readily obtained from experimentally infected rodents.We investigated the utility of square wave electroporation to deliver transgenes and other macromolecules including fluorescent (Cy3 short interference (si RNA molecules, messenger RNAs, and virions into eggs of Schistosoma mansoni. First, eggs were incubated in Cy3-labeled siRNA with and without square wave electroporation. Cy3-signals were detected by fluorescence microscopy in eggs and miracidia hatched from treated eggs. Second, electroporation was employed to introduce mRNA encoding firefly luciferase into eggs. Luciferase activity was detected three hours later, whereas luciferase was not evident in eggs soaked in the mRNA. Third, schistosome eggs were exposed to Moloney murine leukemia virus virions (MLV pseudotyped with vesicular stomatitis virus glycoprotein (VSVG. Proviral transgenes were detected by PCR in genomic DNA from miracidia hatched from virion-exposed eggs, indicating the presence of transgenes in larval schistosomes that had been either soaked or electroporated. However, quantitative PCR (qPCR analysis determined that electroporation of virions resulted in 2-3 times as many copies of provirus in these schistosomes compared to soaking alone. In addition, relative qPCR indicated a copy number for the proviral luciferase transgene of approximately 20 copies for 100 copies of a representative single copy endogenous gene (encoding cathepsin D.Square wave electroporation facilitates introduction of transgenes into the schistosome egg. Electroporation was more effective for the transduction of eggs with pseudotyped MLV than simply soaking the eggs in virions. These findings underscore the

  15. Transfer of UL41, the gene controlling virion-associated host cell shutoff, between different strains of herpes simplex virus.

    Science.gov (United States)

    Fenwick, M L; Everett, R D

    1990-02-01

    Studies with mutant viruses have suggested that the product of gene UL41 of herpes simplex virus type 1 (HSV-1) controls the virion-mediated inhibition of cellular protein synthesis as well as the rate of degradation of viral mRNAs. HSV-1 strain 17+ has a weak host shutoff function, whereas HSV-2 strain G shuts off strongly. A gene of HSV-2(G), judged from its position in the genome to be the probable analogue of gene UL41 of HSV-1, was inserted into the nonessential thymidine kinase gene of HSV-1(17+). The recombinant virus, 17G41, exhibited a strong shutoff function and its immediate early mRNA did not accumulate in the presence of cycloheximide. It resembled HSV-2(G) in these respects and not the parent, confirming the function of the transferred gene. Recombinant virus 17G41 carries the UL41 genes of both strains, 17+ and G, and in this situation the strong shutoff function was dominant. However, after mixed infection with equal multiplicities of 17G41 and HSV-1(17+) the weak shutoff function was dominant. The recombinant, 17G41, was further modified by insertion of a lacZ expression cassette into the coding region of the original gene UL41 (17+). The resulting virus, 17(41-)G41, also had a strong shutoff activity but grew poorly in tissue culture.

  16. Herpes simplex virus virion host shutoff protein requires a mammalian factor for efficient in vitro endoribonuclease activity.

    Science.gov (United States)

    Lu, P; Jones, F E; Saffran, H A; Smiley, J R

    2001-02-01

    The virion host shutoff protein (vhs) of herpes simplex virus (HSV) triggers global shutoff of host protein synthesis and accelerated mRNA turnover during virus infection and induces endoribonucleolytic cleavage of exogenous RNA substrates when it is produced in a rabbit reticulocyte (RRL) in vitro translation system. Although vhs induces RNA turnover in the absence of other HSV gene products, it is not yet known whether cellular factors are required for its activity. As one approach to addressing this question, we expressed vhs in the budding yeast Saccharomyces cerevisiae. Expression of vhs inhibited colony formation, and the severity of this effect varied with the carbon source. The biological relevance of this effect was assessed by examining the activity of five mutant forms of vhs bearing previously characterized in-frame linker insertions. The results indicated a complete concordance between the growth inhibition phenotype in yeast and mammalian host cell shutoff. Despite these results, expression of vhs did not trigger global mRNA turnover in vivo, and cell extracts of yeast expressing vhs displayed little if any vhs-dependent endoribonuclease activity. However, activity was readily detected when such extracts were mixed with RRL. These data suggest that the vhs-dependent endoribonuclease requires one or more mammalian macromolecular factors for efficient activity.

  17. Concanavalin A-mediated cell agglutinability induced by Vaccinia virions. [Uv radiation, /sup 125/I tracer technique

    Energy Technology Data Exchange (ETDEWEB)

    Mbuy, G.; Bubel, H.C.

    1978-12-01

    The induction of enhanced concanavalin A (Con A)-mediated cellular agglutinability by purified vaccinia virus was examined quantitatively. Increased HEp-2 cell agglutinability by the lectin occurred within the first hour of infection and persisted without further change throughout the virus infectious cycle. Ultraviolet, but not heat-inactivated, virus was as effective as infectious virus in causing increased Con A agglutinability. Inhibition of viral and host cell protein synthesis by Streptovitacin A failed to alter the lectin response to vaccinia virus infection. Fluorescein-labeled Con A was observed to form clusters and large fluorescent patches on the infected cell surface during the earliest stage of infection. Studies with /sup 125/I-labeled Con A revealed an early but minimal increase in lectin binding to infected cells. After the first hour of infection, no further increase in Con A binding was observed. When cells were exposed to purified vaccinia virus surface tubules increased Con A agglutinability comparable to that obtained with native virus was demonstrated. Con A-mediated agglutinability of cells was temperature-dependent and displayed a higher temperature transition in infected cells. These data suggest that upon contact with the host cell, vaccinia virions or surface tubules induce alterations in the plasma membrane which are reflected in an enhanced agglutinability by Con A.

  18. Virion stability is important for the circulative transmission of tomato yellow leaf curl sardinia virus by Bemisia tabaci, but virion access to salivary glands does not guarantee transmissibility.

    Science.gov (United States)

    Caciagli, Piero; Medina Piles, Vicente; Marian, Daniele; Vecchiati, Manuela; Masenga, Vera; Mason, Giovanna; Falcioni, Tania; Noris, Emanuela

    2009-06-01

    The capsid protein (CP) of the monopartite begomovirus Tomato yellow leaf curl Sardinia virus (TYLCSV), family Geminiviridae, is indispensable for plant infection and vector transmission. A region between amino acids 129 and 152 is critical for virion assembly and insect transmissibility. Two previously described mutants, one with a double Q129P Q134H mutation (PNHD) and another with a further D152E change (PNHE), were found nontransmissible (NT). Another NT mutant with a single N130D change (QDQD) was retrieved from a new mutational analysis. In this study, these three NT mutants and the wild-type (wt) virus were compared in their relationships with the whitefly vector Bemisia tabaci and the nonvector Trialeurodes vaporariorum. Retention kinetics of NT mutants were analyzed by quantitative dot blot hybridization in whiteflies fed on infected plants. The QDQD mutant, whose virions appeared nongeminate following purification, was hardly detectable in either whitefly species at any sampling time. The PNHD mutant was acquired and circulated in both whitefly species for up to 10 days, like the wt virus, while PNHE circulated in B. tabaci only. Using immunogold labeling, both PNHD and PNHE CPs were detected in B. tabaci salivary glands (SGs) like the wt virus, while no labeling was found in any whitefly tissue with the QDQD mutant. Significant inhibition of transmission of the wt virus was observed after prior feeding of the insects on plants infected with the PNHE mutant, but not on plants infected with the other mutants. Virion stability and ability to cross the SG barrier are necessary for TYLCSV transmission, but interactions with molecular components inside the SGs are also critical for transmissibility.

  19. Immunoelectron microscopic evidence for Tetherin/BST2 as the physical bridge between HIV-1 virions and the plasma membrane.

    Directory of Open Access Journals (Sweden)

    Jason Hammonds

    2010-02-01

    Full Text Available Tetherin/BST2 was identified in 2008 as the cellular factor responsible for restricting HIV-1 replication at a very late stage in the lifecycle. Tetherin acts to retain virion particles on the plasma membrane after budding has been completed. Infected cells that express large amounts of tetherin display large strings of HIV virions that remain attached to the plasma membrane. Vpu is an HIV-1 accessory protein that specifically counteracts the restriction to virus release contributed by tetherin. Tetherin is an unusual Type II transmembrane protein that contains a GPI anchor at its C-terminus and is found in lipid rafts. The leading model for the mechanism of action of tetherin is that it functions as a direct physical tether bridging virions and the plasma membrane. However, evidence that tetherin functions as a physical tether has thus far been indirect. Here we demonstrate by biochemical and immunoelectron microscopic methods that endogenous tetherin is present on the viral particle and forms a bridge between virion particles and the plasma membrane. Endogenous tetherin was found on HIV particles that were released by partial proteolytic digestion. Immunoelectron microscopy performed on HIV-infected T cells demonstrated that tetherin forms an apparent physical link between virions and connects patches of virions to the plasma membrane. Linear filamentous strands that were highly enriched in tetherin bridged the space between some virions. We conclude that tetherin is the physical tether linking HIV-1 virions and the plasma membrane. The presence of filaments with which multiple molecules of tetherin interact in connecting virion particles is strongly suggested by the morphologic evidence.

  20. The vhs1 mutant form of herpes simplex virus virion host shutoff protein retains significant internal ribosome entry site-directed RNA cleavage activity.

    Science.gov (United States)

    Lu, P; Saffran, H A; Smiley, J R

    2001-01-01

    The virion host shutoff (vhs) protein of herpes simplex virus (HSV) triggers global shutoff of host protein synthesis and accelerated turnover of host and viral mRNAs during HSV infection. As well, it induces endoribonucleolytic cleavage of RNA substrates when produced in a rabbit reticulocyte lysate (RRL) in vitro translation system. The vhs1 point mutation (Thr 214-->Ile) eliminates vhs function during virus infection and in transiently transfected mammalian cells and was therefore previously considered to abolish vhs activity. Here we demonstrate that the vhs1 mutant protein induces readily detectable endoribonuclease activity on RNA substrates bearing the internal ribosome entry site of encephalomyocarditis virus in the RRL assay system. These data document that the vhs1 mutation does not eliminate catalytic activity and raise the possibility that the vhs-dependent endoribonuclease employs more than one mode of substrate recognition.

  1. Incorporation of mouse APOBEC3 into murine leukemia virus virions decreases the activity and fidelity of reverse transcriptase.

    Science.gov (United States)

    Boi, Stefano; Kolokithas, Angelo; Shepard, Joyce; Linwood, Rebecca; Rosenke, Kyle; Van Dis, Erik; Malik, Frank; Evans, Leonard H

    2014-07-01

    APOBEC3 proteins are restriction factors that induce G→A hypermutation in retroviruses during replication as a result of cytidine deamination of minus-strand DNA transcripts. However, the mechanism of APOBEC inhibition of murine leukemia viruses (MuLVs) does not appear to be G→A hypermutation and is unclear. In this report, the incorporation of mA3 in virions resulted in a loss in virion reverse transcriptase (RT) activity and RT fidelity that correlated with the loss of virion-specific infectivity.

  2. [Analysis of core virion polypeptides from the pathogen causing chicken egg-drop syndrome].

    Science.gov (United States)

    Iurov, G K; Dadykov, V A; Neugodova, G L; Naroditskiĭ, B S

    1998-01-01

    The cores of egg-drop syndrome virus (EDS-76) were isolated by the pyridine technique. EDS-76 proved to be much more resistant to pyridine disruption than other adenoviruses and treatment with 10% pyridine did not lead to complete dissociation of capsid and cores; only increase of pyridine concentration to 20% produced satisfactory results. At least three polypeptides (24, 10.5, and 6.5 kDa) were found in the core by SDS-PAGE, whereas the 40 kDa reacting with the core is most probably not a core component. Much more intensive reactions of the core with EDS-76 virion capsid suggest that its virion structure differs from that of other adenoviruses.

  3. Structure of Hepatitis E Virion-Sized Particle Reveals an RNA-Dependent Viral Assembly Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Xing, L.; Wall, J.; Li, T.-C.; Mayazaki, N.; Simon, M. N.; Moore, M.; Wang, C.-Y.; Takeda, N.; Wakita, T.; Miyamura, T.; Cheng, R. H.

    2010-10-22

    Hepatitis E virus (HEV) induces acute hepatitis in humans with a high fatality rate in pregnant women. There is a need for anti-HEV research to understand the assembly process of HEV native capsid. Here, we produced a large virion-sized and a small T=1 capsid by expressing the HEV capsid protein in insect cells with and without the N-terminal 111 residues, respectively, for comparative structural analysis. The virion-sized capsid demonstrates a T=3 icosahedral lattice and contains RNA fragment in contrast to the RNA-free T=1 capsid. However, both capsids shared common decameric organization. The in vitro assembly further demonstrated that HEV capsid protein had the intrinsic ability to form decameric intermediate. Our data suggest that RNA binding is the extrinsic factor essential for the assembly of HEV native capsids.

  4. Virology: The Next Generation from Digital PCR to Single Virion Genomics

    Energy Technology Data Exchange (ETDEWEB)

    White, Richard A.; Brazelton De Cardenas, Jessica N.; Hayden, Randall T.

    2015-10-01

    In the past 25 years, virology has had major technology breakthroughs stemming first from the introduction of nucleic acid amplification testing, but more recently from the use of next-generation sequencing, digital PCR, and the possibility of single virion genomics. These technologies have and will improve diagnosis and disease state monitoring in clinical settings, aid in environmental monitoring, and reveal the vast genetic potential of viruses. Using the principle of limiting dilution, digital PCR amplifies single molecules of DNA in highly partitioned endpoint reactions and reads each of those reactions as either positive or negative based on the presence or absence of target fluorophore. In this review, digital PCR will be highlighted along with current studies, advantages/disadvantages, and future perspectives with regard to digital PCR, viral load testing, and the possibility of single virion genomics.

  5. The murine gammaherpesvirus-68 gp150 acts as an immunogenic decoy to limit virion neutralization.

    Directory of Open Access Journals (Sweden)

    Laurent Gillet

    Full Text Available Herpesviruses maintain long-term infectivity without marked antigenic variation. They must therefore evade neutralization by other means. Immune sera block murine gammaherpesvirus-68 (MHV-68 infection of fibroblasts, but fail to block and even enhance its infection of IgG Fc receptor-bearing cells, suggesting that the antibody response to infection is actually poor at ablating virion infectivity completely. Here we analyzed this effect further by quantitating the glycoprotein-specific antibody response of MHV-68 carrier mice. Gp150 was much the commonest glycoprotein target and played a predominant role in driving Fc receptor-dependent infection: when gp150-specific antibodies were boosted, Fc receptor-dependent infection increased; and when gp150-specific antibodies were removed, Fc receptor-dependent infection was largely lost. Neither gp150-specific monoclonal antibodies nor gp150-specific polyclonal sera gave significant virion neutralization. Gp150 therefore acts as an immunogenic decoy, distorting the MHV-68-specific antibody response to promote Fc receptor-dependent infection and so compromise virion neutralization. This immune evasion mechanism may be common to many non-essential herpesvirus glycoproteins.

  6. Modification of Turnip yellow mosaic virus coat protein and its effect on virion assembly

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    Hyun-Il Shin

    2013-10-01

    Full Text Available Turnip yellow mosaic virus (TYMV is a positive strand RNAvirus. We have modified TYMV coat protein (CP by inserting ac-Myc epitope peptide at the N- or C-terminus of the CP, andhave examined its effect on assembly. We introduced therecombinant CP constructs into Nicotiana benthamiana leavesby agroinfiltration. Examination of the leaf extracts by agarosegel electrophoresis and Western blot analysis showed that theCP modified at the N-terminus produced a band co-migratingwith wild-type virions. With C-terminal modification, however,the detected bands moved faster than the wild-type virions. Tofurther examine the effect, TYMV constructs producing themodified CPs were prepared. With N-terminal modification,viral RNAs were protected from RNase A. In contrast, the viralRNAs were not protected with C-terminal modification.Overall, the results suggest that virion assembly and RNApackaging occur properly when the N-terminus of CP ismodified, but not when the C-terminus is modified. [BMBReports 2013; 46(10: 495-500

  7. Virion-incorporated alpha-enolase suppresses the early stage of HIV-1 reverse transcription.

    Science.gov (United States)

    Kishimoto, Naoki; Iga, Nozomi; Yamamoto, Kengo; Takamune, Nobutoki; Misumi, Shogo

    2017-03-04

    Human immunodeficiency virus type-1 (HIV-1) particles contain not only viral-encoded but also host-encoded proteins. Interestingly, several studies showed that host proteins play a critical role in viral infectivity, replication and/or immunoreactivity in the next target cells. Here, we show that alpha-enolase (ENO1) is incorporated into HIV-1 virions and the virion-incorporated ENO1 prevents the early stage of HIV-1 reverse transcription. We found that viral particles contain two isoforms of ENO1 with different isoelectric points by two-dimensional electrophoresis. Suppression of ENO1 expression by RNA interference in the HIV-1 producer cells decreased ENO1 incorporation into virions without altering the packaging of viral structural proteins and viral production but increased viral infectivity. Although the low-level-ENO1-packaging virus maintained comparable levels of reverse transcriptase activity, viral genomic RNA and tRNA(Lys3) packaging to the control virus, its levels of early cDNA products of reverse transcription were higher than those of the control virus. In contrast, the high-level-ENO1-packaging virus, which was produced from ENO1-overexpressing cells, showed decreased infectivity and the levels of early cDNA products. Taken together, these findings reveal a novel function of ENO1 as a negative regulation factor targeting HIV-1 reverse transcription.

  8. Identification of the Nucleocapsid, Tegument, and Envelope Proteins of the Shrimp White Spot Syndrome Virus Virion

    Science.gov (United States)

    Tsai, Jyh-Ming; Wang, Han-Ching; Leu, Jiann-Horng; Wang, Andrew H.-J.; Zhuang, Ying; Walker, Peter J.; Kou, Guang-Hsiung; Lo, Chu-Fang

    2006-01-01

    The protein components of the white spot syndrome virus (WSSV) virion have been well established by proteomic methods, and at least 39 structural proteins are currently known. However, several details of the virus structure and assembly remain controversial, including the role of one of the major structural proteins, VP26. In this study, Triton X-100 was used in combination with various concentrations of NaCl to separate intact WSSV virions into distinct fractions such that each fraction contained envelope and tegument proteins, tegument and nucleocapsid proteins, or nucleocapsid proteins only. From the protein profiles and Western blotting results, VP26, VP36A, VP39A, and VP95 were all identified as tegument proteins distinct from the envelope proteins (VP19, VP28, VP31, VP36B, VP38A, VP51B, VP53A) and nucleocapsid proteins (VP664, VP51C, VP60B, VP15). We also found that VP15 dissociated from the nucleocapsid at high salt concentrations, even though DNA was still present. These results were confirmed by CsCl isopycnic centrifugation followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and liquid chromatography-nanoelectrospray ionization-tandem mass spectrometry, by a trypsin sensitivity assay, and by an immunogold assay. Finally, we propose an assembly process for the WSSV virion. PMID:16501111

  9. The virion of Cafeteria roenbergensis virus (CroV) contains a complex suite of proteins for transcription and DNA repair.

    Science.gov (United States)

    Fischer, Matthias G; Kelly, Isabelle; Foster, Leonard J; Suttle, Curtis A

    2014-10-01

    Cafeteria roenbergensis virus (CroV) is a giant virus of the Mimiviridae family that infects the marine phagotrophic flagellate C. roenbergensis. CroV possesses a DNA genome of ~730 kilobase pairs that is predicted to encode 544 proteins. We analyzed the protein composition of purified CroV particles by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and identified 141 virion-associated CroV proteins and 60 host proteins. Data are available via ProteomeXchange with identifier PXD000993. Predicted functions could be assigned to 36% of the virion proteins, which include structural proteins as well as enzymes for transcription, DNA repair, redox reactions and protein modification. Homologs of 36 CroV virion proteins have previously been found in the virion of Acanthamoeba polyphaga mimivirus. The overlapping virion proteome of CroV and Mimivirus reveals a set of conserved virion protein functions that were presumably present in the last common ancestor of the Mimiviridae. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Virus-producing cells determine the host protein profiles of HIV-1 virion cores

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    Santos Steven

    2012-08-01

    Full Text Available Abstract Background Upon HIV entry into target cells, viral cores are released and rearranged into reverse transcription complexes (RTCs, which support reverse transcription and also protect and transport viral cDNA to the site of integration. RTCs are composed of viral and cellular proteins that originate from both target and producer cells, the latter entering the target cell within the viral core. However, the proteome of HIV-1 viral cores in the context of the type of producer cells has not yet been characterized. Results We examined the proteomic profiles of the cores purified from HIV-1 NL4-3 virions assembled in Sup-T1 cells (T lymphocytes, PMA and vitamin D3 activated THP1 (model of macrophages, mMΦ, and non-activated THP1 cells (model of monocytes, mMN and assessed potential involvement of identified proteins in the early stages of infection using gene ontology information and data from genome-wide screens on proteins important for HIV-1 replication. We identified 202 cellular proteins incorporated in the viral cores (T cells: 125, mMΦ: 110, mMN: 90 with the overlap between these sets limited to 42 proteins. The groups of RNA binding (29, DNA binding (17, cytoskeleton (15, cytoskeleton regulation (21, chaperone (18, vesicular trafficking-associated (12 and ubiquitin-proteasome pathway-associated proteins (9 were most numerous. Cores of the virions from SupT1 cells contained twice as many RNA binding proteins as cores of THP1-derived virus, whereas cores of virions from mMΦ and mMN were enriched in components of cytoskeleton and vesicular transport machinery, most probably due to differences in virion assembly pathways between these cells. Spectra of chaperones, cytoskeletal proteins and ubiquitin-proteasome pathway components were similar between viral cores from different cell types, whereas DNA-binding and especially RNA-binding proteins were highly diverse. Western blot analysis showed that within the group of overlapping proteins

  11. Prostaglandin E2 reduces the release and infectivity of new cell-free virions and cell-to-cell HIV-1 transfer.

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    María Isabel Clemente

    Full Text Available BACKGROUND: The course of human immunodeficiency virus type-1 (HIV-1 infection is influenced by a complex interplay between viral and host factors. HIV infection stimulates several proinflammatory genes, such as cyclooxigense-2 (COX-2, which leads to an increase in prostaglandin (PG levels in the plasma of HIV-1-infected patients. These genes play an indeterminate role in HIV replication and pathogenesis. The effect of prostaglandin E2 (PGE2 on HIV infection is quite controversial and even contradictory, so we sought to determine the role of PGE2 and the signal transduction pathways involved in HIV infection to elucidate possible new targets for antiretrovirals. RESULTS: Our results suggest that PGE2 post-infection treatment acts in the late stages of the viral cycle to reduce HIV replication. Interestingly, viral protein synthesis was not affected, but a loss of progeny virus production was observed. No modulation of CD4 CXCR4 and CCR5 receptor expression, cell proliferation, or activation after PGE2 treatment was detected. Moreover, PGE2 induced an increase in intracellular cAMP (cyclic AMP levels through the EP2/EP4 receptors. PGE2 effects were mimicked by dbcAMP and by a specific Epac (exchange protein directly activated by cyclic AMP agonist, 8-Cpt-cAMP. Treatment with PGE2 increased Rap1 activity, decreased RhoA activity and subsequently reduced the polymerization of actin by approximately 30% compared with untreated cells. In connection with this finding, polarized viral assembly platforms enriched in Gag were disrupted, altering HIV cell-to-cell transfer and the infectivity of new virions. CONCLUSIONS: Our results demonstrate that PGE2, through Epac and Rap activation, alters the transport of newly synthesized HIV-1 components to the assembly site, reducing the release and infectivity of new cell-free virions and cell-to-cell HIV-1 transfer.

  12. A targeted spatial-temporal proteomics approach implicates multiple cellular trafficking pathways in human cytomegalovirus virion maturation.

    Science.gov (United States)

    Moorman, Nathaniel J; Sharon-Friling, Ronit; Shenk, Thomas; Cristea, Ileana M

    2010-05-01

    The assembly of infectious virus particles is a complex event. For human cytomegalovirus (HCMV) this process requires the coordinated expression and localization of at least 60 viral proteins that comprise the infectious virion. To gain insight into the mechanisms controlling this process, we identified protein binding partners for two viral proteins, pUL99 (also termed pp28) and pUL32 (pp150), which are essential for HCMV virion assembly. We utilized HCMV strains expressing pUL99 or pUL32 carboxyl-terminal green fluorescent protein fusion proteins from their native location in the HCMV genome. Based on the presence of ubiquitin in the pUL99 immunoisolation, we discovered that this viral protein colocalizes with components of the cellular endosomal sorting complex required for transport (ESCRT) pathway during the initial stages of virion assembly. We identified the nucleocapsid and a large number of tegument proteins as pUL32 binding partners, suggesting that events controlling trafficking of this viral protein in the cytoplasm regulate nucleocapsid/tegument maturation. The finding that pUL32, but not pUL99, associates with clathrin led to the discovery that the two viral proteins traffic via distinct pathways during the early stages of virion assembly. Additional investigation revealed that the majority of the major viral glycoprotein gB initially resides in a third compartment. Analysis of the trafficking of these three viral proteins throughout a time course of virion assembly allowed us to visualize their merger into a single large cytoplasmic structure during the late stages of viral assembly. We propose a model of HCMV virion maturation in which multiple components of the virion traffic independently of one another before merging.

  13. Ebola virion attachment and entry into human macrophages profoundly effects early cellular gene expression.

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    Victoria Wahl-Jensen

    2011-10-01

    Full Text Available Zaire ebolavirus (ZEBOV infections are associated with high lethality in primates. ZEBOV primarily targets mononuclear phagocytes, which are activated upon infection and secrete mediators believed to trigger initial stages of pathogenesis. The characterization of the responses of target cells to ZEBOV infection may therefore not only further understanding of pathogenesis but also suggest possible points of therapeutic intervention. Gene expression profiles of primary human macrophages exposed to ZEBOV were determined using DNA microarrays and quantitative PCR to gain insight into the cellular response immediately after cell entry. Significant changes in mRNA concentrations encoding for 88 cellular proteins were observed. Most of these proteins have not yet been implicated in ZEBOV infection. Some, however, are inflammatory mediators known to be elevated during the acute phase of disease in the blood of ZEBOV-infected humans. Interestingly, the cellular response occurred within the first hour of Ebola virion exposure, i.e. prior to virus gene expression. This observation supports the hypothesis that virion binding or entry mediated by the spike glycoprotein (GP(1,2 is the primary stimulus for an initial response. Indeed, ZEBOV virions, LPS, and virus-like particles consisting of only the ZEBOV matrix protein VP40 and GP(1,2 (VLP(VP40-GP triggered comparable responses in macrophages, including pro-inflammatory and pro-apoptotic signals. In contrast, VLP(VP40 (particles lacking GP(1,2 caused an aberrant response. This suggests that GP(1,2 binding to macrophages plays an important role in the immediate cellular response.

  14. Thermal conversion of filamentous potato virus X into spherical particles with different properties from virions.

    Science.gov (United States)

    Nikitin, Nikolai; Ksenofontov, Alexander; Trifonova, Ekaterina; Arkhipenko, Marina; Petrova, Ekaterina; Kondakova, Olga; Kirpichnikov, Mikhail; Atabekov, Joseph; Dobrov, Evgeny; Karpova, Olga

    2016-05-01

    We developed a method for the fast transformation of virions of tobacco mosaic virus (TMV) in so-called spherical particles (SPs) of different sizes. These SPs turned out to be highly useful for the preparation of different kinds of important biotechnological products. In this communication, we report that a representative of the flexuous helical virus group-potato virus X (PVX), produces SPs as well, but these SPs differ from TMV SPs in several important aspects. PVX SPs may be useful biotechnological devices.

  15. Exocytosis of Varicella-Zoster Virus Virions Involves a Convergence of Endosomal and Autophagy Pathways

    Science.gov (United States)

    Buckingham, Erin M.; Jarosinski, Keith W.; Jackson, Wallen; Carpenter, John E.

    2016-01-01

    ABSTRACT Varicella-zoster virus (VZV) is an extremely cell-associated herpesvirus with limited egress of viral particles. The induction of autophagy in VZV-infected monolayers is easily detectable; inhibition of autophagy leads to decreased VZV glycoprotein biosynthesis and diminished viral titers. To explain how autophagic flux could exert a proviral effect on the VZV infectious cycle, we postulated that the VZV exocytosis pathway following secondary envelopment may converge with the autophagy pathway. This hypothesis depended on known similarities between VZV gE and autophagy-related (Atg) Atg9/Atg16L1 trafficking pathways. Investigations were carried out with highly purified fractions of VZV virions. When the virion fraction was tested for the presence of autophagy and endosomal proteins, microtubule-associated protein 1 light chain (MAP1LC3B) and Ras-like GTPase 11 (Rab11) were detected. By two-dimensional (2D) and 3D imaging after immunolabeling, both proteins also colocalized with VZV gE in a proportion of cytoplasmic vesicles. When purified VZV virions were enumerated after immunoelectron microscopy, gold beads were detected on viruses following incubation with antibodies to VZV gE (∼100%), Rab11 (50%), and LC3B (30%). Examination of numerous electron micrographs demonstrated that enveloped virions were housed in single-membraned vesicles; viral particles were not observed in autophagosomes. Taken together, our data suggested that some viral particles after secondary envelopment accumulated in a heterogeneous population of single-membraned vesicular compartments, which were decorated with components from both the endocytic pathway (Rab11) and the autophagy pathway (LC3B). The latter cytoplasmic viral vesicles resembled an amphisome. IMPORTANCE VZV infection leads to increased autophagic flux, while inhibition of autophagy leads to a marked reduction in virus spread. In this investigation of the proviral role of autophagy, we found evidence for an

  16. Newly synthesized APOBEC3G is incorporated into HIV virions, inhibited by HIV RNA, and subsequently activated by RNase H.

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    Vanessa B Soros

    2007-02-01

    Full Text Available APOBEC3G (A3G is a potent antiretroviral deoxycytidine deaminase that, when incorporated into HIV virions, hypermutates nascent viral DNA formed during reverse transcription. HIV Vif counters the effect of A3G by depleting intracellular stores of the enzyme, thereby blocking its virion incorporation. Through pulse-chase analyses, we demonstrate that virion A3G is mainly recruited from the cellular pool of newly synthesized enzyme compared to older "mature" A3G already residing in high-molecular-mass RNA-protein complexes. Virion-incorporated A3G forms a large complex with viral genomic RNA that is clearly distinct from cellular HMM A3G complexes, as revealed by both gel filtration and biochemical fractionation. Unexpectedly, the enzymatic activity of virion-incorporated A3G is lost upon its stable association with HIV RNA. The activity of the latent A3G enzyme is ultimately restored during reverse transcription by the action of HIV RNase H. Degradation of the viral genomic RNA by RNase H not only generates the minus-strand DNA substrate targeted by A3G for hypermutation but also removes the inhibitory RNA bound to A3G, thereby enabling its function as a deoxycytidine deaminase. These findings highlight an unexpected interplay between host and virus where initiation of antiviral enzymatic activity is dependent on the action of an essential viral enzyme.

  17. Target-dependent enrichment of virions determines the reduction of high-throughput sequencing in virus discovery.

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    Randi Holm Jensen

    Full Text Available Viral infections cause many different diseases stemming both from well-characterized viral pathogens but also from emerging viruses, and the search for novel viruses continues to be of great importance. High-throughput sequencing is an important technology for this purpose. However, viral nucleic acids often constitute a minute proportion of the total genetic material in a sample from infected tissue. Techniques to enrich viral targets in high-throughput sequencing have been reported, but the sensitivity of such methods is not well established. This study compares different library preparation techniques targeting both DNA and RNA with and without virion enrichment. By optimizing the selection of intact virus particles, both by physical and enzymatic approaches, we assessed the effectiveness of the specific enrichment of viral sequences as compared to non-enriched sample preparations by selectively looking for and counting read sequences obtained from shotgun sequencing. Using shotgun sequencing of total DNA or RNA, viral targets were detected at concentrations corresponding to the predicted level, providing a foundation for estimating the effectiveness of virion enrichment. Virion enrichment typically produced a 1000-fold increase in the proportion of DNA virus sequences. For RNA virions the gain was less pronounced with a maximum 13-fold increase. This enrichment varied between the different sample concentrations, with no clear trend. Despite that less sequencing was required to identify target sequences, it was not evident from our data that a lower detection level was achieved by virion enrichment compared to shotgun sequencing.

  18. Orsay virus utilizes ribosomal frameshifting to express a novel protein that is incorporated into virions

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    Jiang, Hongbing; Franz, Carl J.; Wu, Guang; Renshaw, Hilary; Zhao, Guoyan [Departments of Molecular Microbiology and Pathology and Immunology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110 (United States); Firth, Andrew E. [Department of Pathology, University of Cambridge, Cambridge CB2 1QP (United Kingdom); Wang, David, E-mail: davewang@borcim.wustl.edu [Departments of Molecular Microbiology and Pathology and Immunology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110 (United States)

    2014-02-15

    Orsay virus is the first identified virus that is capable of naturally infecting Caenorhabditis elegans. Although it is most closely related to nodaviruses, Orsay virus differs from nodaviruses in its genome organization. In particular, the Orsay virus RNA2 segment encodes a putative novel protein of unknown function, termed delta, which is absent from all known nodaviruses. Here we present evidence that Orsay virus utilizes a ribosomal frameshifting strategy to express a novel fusion protein from the viral capsid (alpha) and delta ORFs. Moreover, the fusion protein was detected in purified virus fractions, demonstrating that it is most likely incorporated into Orsay virions. Furthermore, N-terminal sequencing of both the fusion protein and the capsid protein demonstrated that these proteins must be translated from a non-canonical initiation site. While the function of the alpha–delta fusion remains cryptic, these studies provide novel insights into the fundamental properties of this new clade of viruses. - Highlights: • Orsay virus encodes a novel fusion protein by a ribosomal frameshifting mechanism. • Orsay capsid and fusion protein is translated from a non-canonical initiation site. • The fusion protein is likely incorporated into Orsay virions.

  19. Proteomic analysis of the herpes simplex virus 1 virion protein 16 transactivator protein in infected cells.

    Science.gov (United States)

    Suk, Hyung; Knipe, David M

    2015-06-01

    The herpes simplex virus 1 virion protein 16 (VP16) tegument protein forms a transactivation complex with the cellular proteins host cell factor 1 (HCF-1) and octamer-binding transcription factor 1 (Oct-1) upon entry into the host cell. VP16 has also been shown to interact with a number of virion tegument proteins and viral glycoprotein H to promote viral assembly, but no comprehensive study of the VP16 proteome has been performed at early times postinfection. We therefore performed a proteomic analysis of VP16-interacting proteins at 3 h postinfection. We confirmed the interaction of VP16 with HCF-1 and a large number of cellular Mediator complex proteins, but most surprisingly, we found that the major viral protein associating with VP16 is the infected cell protein 4 (ICP4) immediate-early (IE) transactivator protein. These results raise the potential for a new function for VP16 in associating with the IE ICP4 and playing a role in transactivation of early and late gene expression, in addition to its well-documented function in transactivation of IE gene expression. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Immunogenicity Studies of Bivalent Inactivated Virions of EV71/CVA16 Formulated with Submicron Emulsion Systems

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    Chih-Wei Lin

    2014-01-01

    Full Text Available We assessed two strategies for preparing candidate vaccines against hand, foot, and mouth disease (HFMD caused mainly by infections of enterovirus (EV 71 and coxsackievirus (CV A16. We firstly design and optimize the potency of adjuvant combinations of emulsion-based delivery systems, using EV71 candidate vaccine as a model. We then perform immunogenicity studies in mice of EV71/CVA16 antigen combinations formulated with PELC/CpG. A single dose of inactivated EV71 virion (0.2 μg emulsified in submicron particles was found (i to induce potent antigen-specific neutralizing antibody responses and (ii consistently to elicit broad antibody responses against EV71 neutralization epitopes. A single dose immunogenicity study of bivalent activated EV71/CVA16 virion formulated with either Alum or PELC/CpG adjuvant showed that CVA16 antigen failed to elicit CVA16 neutralizing antibody responses and did not affect EV71-specific neutralizing antibody responses. A boosting dose of emulsified EV71/CVA16 bivalent vaccine candidate was found to be necessary to achieve high seroconversion of CVA16-specific neutralizing antibody responses. The current results are important for the design and development of prophylactic vaccines against HFMD and other emerging infectious diseases.

  1. Expression of Aedes trypsin-modulating oostatic factor on the virion of TMV: A potential larvicide.

    Science.gov (United States)

    Borovsky, Dov; Rabindran, Shailaja; Dawson, William O; Powell, Charles A; Iannotti, Donna A; Morris, Timothy J; Shabanowitz, Jeffry; Hunt, Donald F; DeBondt, Hendrik L; DeLoof, Arnold

    2006-12-12

    We report the engineering of the surface of the tobacco mosaic virus (TMV) virion with a mosquito decapeptide hormone, trypsin-modulating oostatic factor (TMOF). The TMV coat protein (CP) was fused to TMOF at the C terminus by using a read-through, leaky stop codon that facilitated expression of CP and chimeric CP-TMOF (20:1 ratio) that were coassembled into virus particles in infected Nicotiana tabacum. Plants that were infected with the hybrid TMV RNA accumulated TMOF to levels of 1.3% of total soluble protein. Infected tobacco leaf discs that were fed to Heliothis virescens fourth-instar larvae stunted their growth and inhibited trypsin and chymotrypsin activity in their midgut. Purified CP-TMOF virions fed to mosquito larvae stopped larval growth and caused death. Because TMV has a wide host range, expressing TMV-TMOF in plants can be used as a general method to protect them against agricultural insect pests and to control vector mosquitoes.

  2. Gp120 on HIV-1 Virions Lacks O-Linked Carbohydrate.

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    Elizabeth Stansell

    Full Text Available As HIV-1-encoded envelope protein traverses the secretory pathway, it may be modified with N- and O-linked carbohydrate. When the gp120s of HIV-1 NL4-3, HIV-1 YU2, HIV-1 Bal, HIV-1 JRFL, and HIV-1 JRCSF were expressed as secreted proteins, the threonine at consensus position 499 was found to be O-glycosylated. For SIVmac239, the corresponding threonine was also glycosylated when gp120 was recombinantly expressed. Similarly-positioned, highly-conserved threonines in the influenza A virus H1N1 HA1 and H5N1 HA1 envelope proteins were also found to carry O-glycans when expressed as secreted proteins. In all cases, the threonines were modified predominantly with disialylated core 1 glycans, together with related core 1 and core 2 structures. Secreted HIV-1 gp140 was modified to a lesser extent with mainly monosialylated core 1 O-glycans, suggesting that the ectodomain of the gp41 transmembrane component may limit the accessibility of Thr499 to glycosyltransferases. In striking contrast to these findings, gp120 on purified virions of HIV-1 Bal and SIV CP-MAC lacked any detectable O-glycosylation of the C-terminal threonine. Our results indicate the absence of O-linked carbohydrates on Thr499 as it exists on the surface of virions and suggest caution in the interpretation of analyses of post-translational modifications that utilize recombinant forms of envelope protein.

  3. Quantitative Determination of Cucumber Mosaic Virus Genome RNAs in Virions by Real-Time Reverse Transcription-Polymerase Chain Reaction

    Institute of Scientific and Technical Information of China (English)

    Jun-Li FENG; Shao-Ning CHEN; Xiang-Shan TANG; Xian-Feng DING; Zhi-You DU; Ji-Shuang CHEN

    2006-01-01

    A real-time RT-PCR procedure using the green fluorescent dye SYBR Green I was developed for determining the absolute and relative copies of cucumber mosaic virus (CMV) genomic RNAs contained in purified virions. Primers specific to each CMV ORF were designed and selected. Sequences were then amplified with length varying from 61 to 153 bp. Using dilution series of CMV genome RNAs prepared by in vitro transcription as the standard samples, a good linear correlation was observed between their threshold cycle (Ct)values and the logarithms of the initial template amounts. The copies of genomic RNA 1, RNA 2,RNA 3 and the subgenomic RNA 4 in CMV virions were quantified by this method, and the ratios were about Our work is the first report concerning the relative amounts of different RNA fragments in CMV virions as a virus with tripartite genome.

  4. Human Cytomegalovirus gH/gL Forms a Stable Complex with the Fusion Protein gB in Virions.

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    Adam L Vanarsdall

    2016-04-01

    Full Text Available Human cytomegalovirus (HCMV is a ubiquitous virus that is a major pathogen in newborns and immunocompromised or immunosuppressed patients. HCMV infects a wide variety of cell types using distinct entry pathways that involve different forms of the gH/gL glycoprotein: gH/gL/gO and gH/gL/UL128-131 as well as the viral fusion glycoprotein, gB. However, the minimal or core fusion machinery (sufficient for cell-cell fusion is just gH/gL and gB. Here, we demonstrate that HCMV gB and gH/gL form a stable complex early after their synthesis and in the absence of other viral proteins. gH/gL can interact with gB mutants that are unable to mediate cell-cell fusion. gB-gH/gL complexes included as much as 16-50% of the total gH/gL in HCMV virus particles. In contrast, only small amounts of gH/gL/gO and gH/gL/UL128-131 complexes were found associated with gB. All herpesviruses express gB and gH/gL molecules and most models describing herpesvirus entry suggest that gH/gL interacts with gB to mediate membrane fusion, although there is no direct evidence for this. For herpes simplex virus (HSV-1 it has been suggested that after receptor binding gH/gL binds to gB either just before, or coincident with membrane fusion. Therefore, our results have major implications for these models, demonstrating that HCMV gB and gH/gL forms stable gB-gH/gL complexes that are incorporated virions without receptor binding or membrane fusion. Moreover, our data is the best support to date for the proposal that gH/gL interacts with gB.

  5. Human Cytomegalovirus gH/gL Forms a Stable Complex with the Fusion Protein gB in Virions.

    Science.gov (United States)

    Vanarsdall, Adam L; Howard, Paul W; Wisner, Todd W; Johnson, David C

    2016-04-01

    Human cytomegalovirus (HCMV) is a ubiquitous virus that is a major pathogen in newborns and immunocompromised or immunosuppressed patients. HCMV infects a wide variety of cell types using distinct entry pathways that involve different forms of the gH/gL glycoprotein: gH/gL/gO and gH/gL/UL128-131 as well as the viral fusion glycoprotein, gB. However, the minimal or core fusion machinery (sufficient for cell-cell fusion) is just gH/gL and gB. Here, we demonstrate that HCMV gB and gH/gL form a stable complex early after their synthesis and in the absence of other viral proteins. gH/gL can interact with gB mutants that are unable to mediate cell-cell fusion. gB-gH/gL complexes included as much as 16-50% of the total gH/gL in HCMV virus particles. In contrast, only small amounts of gH/gL/gO and gH/gL/UL128-131 complexes were found associated with gB. All herpesviruses express gB and gH/gL molecules and most models describing herpesvirus entry suggest that gH/gL interacts with gB to mediate membrane fusion, although there is no direct evidence for this. For herpes simplex virus (HSV-1) it has been suggested that after receptor binding gH/gL binds to gB either just before, or coincident with membrane fusion. Therefore, our results have major implications for these models, demonstrating that HCMV gB and gH/gL forms stable gB-gH/gL complexes that are incorporated virions without receptor binding or membrane fusion. Moreover, our data is the best support to date for the proposal that gH/gL interacts with gB.

  6. Understanding the Process of Envelope Glycoprotein Incorporation into Virions in Simian and Feline Immunodeficiency Viruses

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    José L. Affranchino

    2014-01-01

    Full Text Available The lentiviral envelope glycoproteins (Env mediate virus entry by interacting with specific receptors present at the cell surface, thereby determining viral tropism and pathogenesis. Therefore, Env incorporation into the virions formed by assembly of the viral Gag polyprotein at the plasma membrane of the infected cells is a key step in the replication cycle of lentiviruses. Besides being useful models of human immunodeficiency virus (HIV infections in humans and valuable tools for developing AIDS therapies and vaccines, simian and feline immunodeficiency viruses (SIV and FIV, respectively are relevant animal retroviruses; the study of which provides important information on how lentiviral replication strategies have evolved. In this review, we discuss the molecular mechanisms underlying the incorporation of the SIV and FIV Env glycoproteins into viral particles.

  7. Electron cryotomography of measles virus reveals how matrix protein coats the ribonucleocapsid within intact virions.

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    Liljeroos, Lassi; Huiskonen, Juha T; Ora, Ari; Susi, Petri; Butcher, Sarah J

    2011-11-01

    Measles virus is a highly infectious, enveloped, pleomorphic virus. We combined electron cryotomography with subvolume averaging and immunosorbent electron microscopy to characterize the 3D ultrastructure of the virion. We show that the matrix protein forms helices coating the helical ribonucleocapsid rather than coating the inner leaflet of the membrane, as previously thought. The ribonucleocapsid is folded into tight bundles through matrix-matrix interactions. The implications for virus assembly are that the matrix already tightly interacts with the ribonucleocapsid in the cytoplasm, providing a structural basis for the previously observed regulation of RNA transcription by the matrix protein. Next, the matrix-covered ribonucleocapsids are transported to the plasma membrane, where the matrix interacts with the envelope glycoproteins during budding. These results are relevant to the nucleocapsid organization and budding of other paramyxoviruses, where isolated matrix has been observed to form helices.

  8. Nuclear Factor kappa B is required for the production of infectious human herpesvirus 8 virions

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    Negin N Blattman

    2014-04-01

    Full Text Available Human herpesvirus 8 (HHV8 infection leads to potent activation of nuclear factor kappa B (NFB in primary and transformed cells. We used recombinant HHV8 (rKSHV.219 expressing green fluorescent protein under the constitutive cellular promoter elongation factor 2 and red fluorescent protein under an early HHV8 lytic gene promoter T1.1, to monitor replication during infection of human foreskin fibroblasts (HF, noting changes in NFB activity. In primary HF, NFB levels do not affect HHV8 ability to establish infection or maintain latency. Furthermore, there was no effect on the percent of cells undergoing reactivation from latency, and there were similar numbers of released and cell associated HHV8 viral particles following reactivation in the presence of inhibitors. Reactivation of HHV8 in latently infected HF in the presence of NFB inhibitors resulted in production of viral particles that did not efficiently establish infection, due to deficiencies in binding and/or entry into normally permissive cells. Exogenous expression of glycoprotein M, an envelope protein involved in viral binding and entry was able to partially overcome the deficiency induced by NFB inhibitors. Our data indicate that in primary cells, NFB is not required for infection, establishment of latency, or entry into the lytic cycle, but is required for the expression of virion associated genes involved in the initial steps of virion infectivity. These studies suggest that strategies to inhibit NFB may prevent HHV8 spread and should be considered as a potential therapeutic target for preventing HHV8 associated diseases.

  9. Localization of the Houdinisome (Ejection Proteins inside the Bacteriophage P22 Virion by Bubblegram Imaging

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    Weimin Wu

    2016-08-01

    Full Text Available The P22 capsid is a T=7 icosahedrally symmetric protein shell with a portal protein dodecamer at one 5-fold vertex. Extending outwards from that vertex is a short tail, and putatively extending inwards is a 15-nm-long α-helical barrel formed by the C-terminal domains of portal protein subunits. In addition to the densely packed genome, the capsid contains three “ejection proteins” (E-proteins [gp7, gp16, and gp20] destined to exit from the tightly sealed capsid during the process of DNA delivery into target cells. We estimated their copy numbers by quantitative SDS-PAGE as approximately 12 molecules per virion of gp16 and gp7 and 30 copies of gp20. To localize them, we used bubblegram imaging, an adaptation of cryo-electron microscopy in which gaseous bubbles induced in proteins by prolonged irradiation are used to map the proteins’ locations. We applied this technique to wild-type P22, a triple mutant lacking all three E-proteins, and three mutants each lacking one E-protein. We conclude that all three E-proteins are loosely clustered around the portal axis, in the region displaced radially inwards from the portal crown. The bubblegram data imply that approximately half of the α-helical barrel seen in the portal crystal structure is disordered in the mature virion, and parts of the disordered region present binding sites for E-proteins. Thus positioned, the E-proteins are strategically placed to pass down the shortened barrel and through the portal ring and the tail, as they exit from the capsid during an infection.

  10. Structural evolution of the P22-like phages: Comparison of Sf6 and P22 procapsid and virion architectures

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    Parent, Kristin N. [University of California, San Diego, Department of Chemistry and Biochemistry, La Jolla, CA 92093 (United States); Gilcrease, Eddie B. [University of Utah School of Medicine, Division of Microbiology and Immunology, Department of Pathology, Salt Lake City, UT 84112 (United States); Casjens, Sherwood R., E-mail: sherwood.casjens@path.utah.edu [University of Utah School of Medicine, Division of Microbiology and Immunology, Department of Pathology, Salt Lake City, UT 84112 (United States); Baker, Timothy S., E-mail: tsb@ucsd.edu [University of California, San Diego, Department of Chemistry and Biochemistry, La Jolla, CA 92093 (United States); University of California, San Diego, Division of Biological Sciences, La Jolla, CA 92093 (United States)

    2012-06-05

    Coat proteins of tailed, dsDNA phages and in herpesviruses include a conserved core similar to the bacteriophage HK97 subunit. This core is often embellished with other domains such as the telokin Ig-like domain of phage P22. Eighty-six P22-like phages and prophages with sequenced genomes share a similar set of virion assembly genes and, based on comparisons of twelve viral assembly proteins (structural and assembly/packaging chaperones), these phages are classified into three groups (P22-like, Sf6-like, and CUS-3-like). We used cryo-electron microscopy and 3D image reconstruction to determine the structures of Sf6 procapsids and virions ({approx} 7 A resolution), and the structure of the entire, asymmetric Sf6 virion (16-A resolution). The Sf6 coat protein is similar to that of P22 yet it has differences in the telokin domain and in its overall quaternary organization. Thermal stability and agarose gel experiments show that Sf6 virions are slightly less stable than those of P22. Finally, bacterial host outer membrane proteins A and C were identified in lipid vesicles that co-purify with Sf6 particles, but are not components of the capsid.

  11. The plant host can affect the encapsidation of brome mosaic virus (BMV) RNA: BMV virions are surprisingly heterogeneous.

    Science.gov (United States)

    Ni, Peng; Vaughan, Robert C; Tragesser, Brady; Hoover, Haley; Kao, C Cheng

    2014-03-01

    Brome mosaic virus (BMV) packages its genomic and subgenomic RNAs into three separate viral particles. BMV purified from barley, wheat, and tobacco have distinct relative abundances of the encapsidated RNAs. We seek to identify the basis for the host-dependent differences in viral RNA encapsidation. Sequencing of the viral RNAs revealed recombination events in the 3' untranslated region of RNA1 of BMV purified from barley and wheat, but not from tobacco. However, the relative amounts of the BMV RNAs that accumulated in barley and wheat are similar and RNA accumulation is not sufficient to account for the difference in RNA encapsidation. Virions purified from barley and wheat were found to differ in their isoelectric points, resistance to proteolysis, and contacts between the capsid residues and the RNA. Mass spectrometric analyses revealed that virions from the three hosts had different post-translational modifications that should impact the physiochemical properties of the virions. Another major source of variation in RNA encapsidation was due to the purification of BMV particles to homogeneity. Highly enriched BMV present in lysates had a surprising range of sizes, buoyant densities, and distinct relative amounts of encapsidated RNAs. These results show that the encapsidated BMV RNAs reflect a combination of host effects on the physiochemical properties of the viral capsids and the enrichment of a subset of virions. The previously unexpected heterogeneity in BMV should influence the timing of the infection and also the host innate immune responses.

  12. Aqueous extracts from peppermint, sage and lemon balm leaves display potent anti-HIV-1 activity by increasing the virion density

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    Baumann Ingo

    2008-03-01

    Full Text Available Abstract Background Aqueous extracts from leaves of well known species of the Lamiaceae family were examined for their potency to inhibit infection by human immunodeficiency virus type 1 (HIV-1. Results Extracts from lemon balm (Melissa officinalis L., peppermint (Mentha × piperita L., and sage (Salvia officinalis L. exhibited a high and concentration-dependent activity against the infection of HIV-1 in T-cell lines, primary macrophages, and in ex vivo tonsil histocultures with 50% inhibitory concentrations as low as 0.004%. The aqueous Lamiaceae extracts did not or only at very high concentrations interfere with cell viability. Mechanistically, extract exposure of free virions potently and rapidly inhibited infection, while exposure of surface-bound virions or target cells alone had virtually no antiviral effect. In line with this observation, a virion-fusion assay demonstrated that HIV-1 entry was drastically impaired following treatment of particles with Lamiaceae extracts, and the magnitude of this effect at the early stage of infection correlated with the inhibitory potency on HIV-1 replication. Extracts were active against virions carrying diverse envelopes (X4 and R5 HIV-1, vesicular stomatitis virus, ecotropic murine leukemia virus, but not against a non-enveloped adenovirus. Following exposure to Lamiaceae extracts, the stability of virions as well as virion-associated levels of envelope glycoprotein and processed Gag protein were unaffected, while, surprisingly, sucrose-density equilibrium gradient analyses disclosed a marked increase of virion density. Conclusion Aqueous extracts from Lamiaceae can drastically and rapidly reduce the infectivity of HIV-1 virions at non-cytotoxic concentrations. An extract-induced enhancement of the virion's density prior to its surface engagement appears to be the most likely mode of action. By harbouring also a strong activity against herpes simplex virus type 2, these extracts may provide a basis

  13. Antigenic properties of the human immunodeficiency virus envelope glycoprotein gp120 on virions bound to target cells.

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    Meron Mengistu

    2015-03-01

    Full Text Available The HIV-1 envelope glycoprotein, gp120, undergoes multiple molecular interactions and structural rearrangements during the course of host cell attachment and viral entry, which are being increasingly defined at the atomic level using isolated proteins. In comparison, antigenic markers of these dynamic changes are essentially unknown for single HIV-1 particles bound to target cells. Such markers should indicate how neutralizing and/or non-neutralizing antibodies might interdict infection by either blocking infection or sensitizing host cells for elimination by Fc-mediated effector function. Here we address this deficit by imaging fluorescently labeled CCR5-tropic HIV-1 pseudoviruses using confocal and superresolution microscopy to track the exposure of neutralizing and non-neutralizing epitopes as they appear on single HIV-1 particles bound to target cells. Epitope exposure was followed under conditions permissive or non-permissive for viral entry to delimit changes associated with virion binding from those associated with post-attachment events. We find that a previously unexpected array of gp120 epitopes is exposed rapidly upon target cell binding. This array comprises both neutralizing and non-neutralizing epitopes, the latter being hidden on free virions yet capable of serving as potent targets for Fc-mediated effector function. Under non-permissive conditions for viral entry, both neutralizing and non-neutralizing epitope exposures were relatively static over time for the majority of bound virions. Under entry-permissive conditions, epitope exposure patterns changed over time on subsets of virions that exhibited concurrent variations in virion contents. These studies reveal that bound virions are distinguished by a broad array of both neutralizing and non-neutralizing gp120 epitopes that potentially sensitize a freshly engaged target cell for destruction by Fc-mediated effector function and/or for direct neutralization at a post-binding step

  14. Low-energy electron holographic imaging of individual tobacco mosaic virions

    Energy Technology Data Exchange (ETDEWEB)

    Longchamp, Jean-Nicolas, E-mail: longchamp@physik.uzh.ch; Latychevskaia, Tatiana; Escher, Conrad; Fink, Hans-Werner [Physics Department, University of Zurich, Winterthurerstrasse 190, 8057 Zurich (Switzerland)

    2015-09-28

    Modern structural biology relies on Nuclear Magnetic Resonance (NMR), X-ray crystallography, and cryo-electron microscopy for gaining information on biomolecules at nanometer, sub-nanometer, or atomic resolution. All these methods, however, require averaging over a vast ensemble of entities, and hence knowledge on the conformational landscape of an individual particle is lost. Unfortunately, there are now strong indications that even X-ray free electron lasers will not be able to image individual molecules but will require nanocrystal samples. Here, we show that non-destructive structural biology of single particles has now become possible by means of low-energy electron holography. As an example, individual tobacco mosaic virions deposited on ultraclean freestanding graphene are imaged at 1 nm resolution revealing structural details arising from the helical arrangement of the outer protein shell of the virus. Since low-energy electron holography is a lens-less technique and since electrons with a deBroglie wavelength of approximately 1 Å do not impose radiation damage to biomolecules, the method has the potential for Angstrom resolution imaging of single biomolecules.

  15. Herpes simplex virus 1 counteracts tetherin restriction via its virion host shutoff activity.

    Science.gov (United States)

    Zenner, Helen L; Mauricio, Rui; Banting, George; Crump, Colin M

    2013-12-01

    The interferon-inducible membrane protein tetherin (Bst-2, or CD317) is an antiviral factor that inhibits enveloped virus release by cross-linking newly formed virus particles to the producing cell. The majority of viruses that are sensitive to tetherin restriction appear to be those that acquire their envelopes at the plasma membrane, although many viruses, including herpesviruses, envelope at intracellular membranes, and the effect of tetherin on such viruses has been less well studied. We investigated the tetherin sensitivity and possible countermeasures of herpes simplex virus 1 (HSV-1). We found that overexpression of tetherin inhibits HSV-1 release and that HSV-1 efficiently depletes tetherin from infected cells. We further show that the virion host shutoff protein (Vhs) is important for depletion of tetherin mRNA and protein and that removal of tetherin compensates for defects in replication and release of a Vhs-null virus. Vhs is known to be important for HSV-1 to evade the innate immune response in vivo. Taken together, our data suggest that tetherin has antiviral activity toward HSV-1 and that the removal of tetherin by Vhs is important for the efficient replication and dissemination of HSV-1.

  16. Gammaherpesviral gene expression and virion composition are broadly controlled by accelerated mRNA degradation.

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    Emma Abernathy

    2014-01-01

    Full Text Available Lytic gammaherpesvirus infection restricts host gene expression by promoting widespread degradation of cytoplasmic mRNA through the activity of the viral endonuclease SOX. Though generally assumed to be selective for cellular transcripts, the extent to which SOX impacts viral mRNA stability has remained unknown. We addressed this issue using the model murine gammaherpesvirus MHV68 and, unexpectedly, found that all stages of viral gene expression are controlled through mRNA degradation. Using both comprehensive RNA expression profiling and half-life studies we reveal that the levels of the majority of viral mRNAs but not noncoding RNAs are tempered by MHV68 SOX (muSOX activity. The targeting of viral mRNA by muSOX is functionally significant, as it impacts intracellular viral protein abundance and progeny virion composition. In the absence of muSOX-imposed gene expression control the viral particles display increased cell surface binding and entry as well as enhanced immediate early gene expression. These phenotypes culminate in a viral replication defect in multiple cell types as well as in vivo, highlighting the importance of maintaining the appropriate balance of viral RNA during gammaherpesviral infection. This is the first example of a virus that fails to broadly discriminate between cellular and viral transcripts during host shutoff and instead uses the targeting of viral messages to fine-tune overall gene expression.

  17. Virion polypeptide heterogeneity among virulent and avirulent strains of eastern equine encephalitis (EEE) virus.

    Science.gov (United States)

    Walder, R; Rosato, R R; Eddy, G A

    1981-01-01

    Comparative analysis of structural virion polypeptides of 24 selected EEE virus strains, representing North and South American types, was performed by one-dimensional discontinuous sodium dodecyl sulfate (SDS)-polyacrylamide-gel electrophoresis (PAGE). The structural proteins of different EEE virus isolates, resolved by this method, exhibited mol.wts. values in the range of 57-60 X 10(3) for (E-1), 51-54 X 10(3) for (E-2) and 35-38 X 10(3) daltons for the core (NP) nucleocapsid. The exception was the South American human lethal virus, TRVL-89287 strain, which was shown to possess only a single envelope glycoprotein. The high molecular weight envelope (E-1) glycoprotein species was absent or co-migrated adjacent to the smaller envelope (E-2) glycoprotein. Results indicated similarities in the core (NP) proteins, however greater variability in the envelope (E-/ and/or E-2) glycoproteins. Based on these variations seven distinct profiles could be observed among the EEE virus strain studied. The classification based on the patterns of structural polypeptides obtained by SDS-PAGE of these strains does not correlate well with any other previously reported in vitro characteristics (antigenic subtypes, HTP elution profiles) nor with the in vivo virulence markers.

  18. The stable association of virion with the triple-gene-block protein 3-based complex of Bamboo mosaic virus.

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    Yuan-Lin Chou

    Full Text Available The triple-gene-block protein 3 (TGBp3 of Bamboo mosaic virus (BaMV is an integral endoplasmic reticulum (ER membrane protein which is assumed to form a membrane complex to deliver the virus intracellularly. However, the virus entity that is delivered to plasmodesmata (PD and its association with TGBp3-based complexes are not known. Results from chemical extraction and partial proteolysis of TGBp3 in membrane vesicles revealed that TGBp3 has a right-side-out membrane topology; i.e., TGBp3 has its C-terminal tail exposed to the outer surface of ER. Analyses of the TGBp3-specific immunoprecipitate of Sarkosyl-extracted TGBp3-based complex revealed that TGBp1, TGBp2, TGBp3, capsid protein (CP, replicase and viral RNA are potential constituents of virus movement complex. Substantial co-fractionation of TGBp2, TGBp3 and CP, but not TGBp1, in the early eluted gel filtration fractions in which virions were detected after TGBp3-specific immunoprecipitation suggested that the TGBp2- and TGBp3-based complex is able to stably associate with the virion. This notion was confirmed by immunogold-labeling transmission electron microscopy (TEM of the purified virions. In addition, mutational and confocal microscopy analyses revealed that TGBp3 plays a key role in virus cell-to-cell movement by enhancing the TGBp2- and TGBp3-dependent PD localization of TGBp1. Taken together, our results suggested that the cell-to-cell movement of potexvirus requires stable association of the virion cargo with the TGBp2- and TGBp3-based membrane complex and recruitment of TGBp1 to the PD by this complex.

  19. BST2/CD317 counteracts human coronavirus 229E productive infection by tethering virions at the cell surface

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shiu-Mei [Department of Medical Research and Education, Taipei Veterans General Hospital and Institute of Clinical Medicine, Taipei 11217, Taiwan (China); Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan (China); Huang, Kuo-Jung [Department of Medical Research and Education, Taipei Veterans General Hospital and Institute of Clinical Medicine, Taipei 11217, Taiwan (China); Wang, Chin-Tien, E-mail: chintien@ym.edu.tw [Department of Medical Research and Education, Taipei Veterans General Hospital and Institute of Clinical Medicine, Taipei 11217, Taiwan (China); Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan (China)

    2014-01-20

    Bone marrow stromal antigen 2 (BST2), an interferon-inducible antiviral factor, has been shown to block the release of various enveloped viruses from cells. It has also been identified as an innate immune system component. Most enveloped viruses subject to BST2 restriction bud at the plasma membrane. Here we report our findings that (a) the production of human coronavirus 229E (HCoV-229E) progeny viruses, whose budding occurs at the ER-Golgi intermediate compartment (ERGIC), markedly decreases in the presence of BST2; and (b) BST2 knockdown expression results in enhanced HCoV-229E virion production. Electron microscopy analyses indicate that HCoV-229E virions are tethered to cell surfaces or intracellular membranes by BST2. Our results suggest that BST2 exerts a broad blocking effect against enveloped virus release, regardless of whether budding occurs at the plasma membrane or intracellular compartments. - Highlights: • BST2 knockdown expression results in enhanced HCoV-229E egress. • HCoV-229E virions are tethered to cell surfaces or intracellular membranes by BST2. • HCoV-229E infection at high MOI can significantly downregulate HeLa BST2 and rescue HIV-1 egress.

  20. Rift Valley fever virus incorporates the 78 kDa glycoprotein into virions matured in mosquito C6/36 cells.

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    Hana M Weingartl

    Full Text Available Rift Valley fever virus (RVFV, genus Phlebovirus, family Bunyaviridae is a zoonotic arthropod-borne virus able to transition between distant host species, causing potentially severe disease in humans and ruminants. Viral proteins are encoded by three genomic segments, with the medium M segment coding for four proteins: nonstructural NSm protein, two glycoproteins Gn and Gc and large 78 kDa glycoprotein (LGp of unknown function. Goat anti-RVFV polyclonal antibody and mouse monoclonal antibody, generated against a polypeptide unique to the LGp within the RVFV proteome, detected this protein in gradient purified RVFV ZH501 virions harvested from mosquito C6/36 cells but not in virions harvested from the mammalian Vero E6 cells. The incorporation of LGp into the mosquito cell line - matured virions was confirmed by immune-electron microscopy. The LGp was incorporated into the virions immediately during the first passage in C6/36 cells of Vero E6 derived virus. Our data indicate that LGp is a structural protein in C6/36 mosquito cell generated virions. The protein may aid the transmission from the mosquitoes to the ruminant host, with a possible role in replication of RVFV in the mosquito host. To our knowledge, this is a first report of different protein composition between virions formed in insect C6/36 versus mammalian Vero E6 cells.

  1. UV-Sensitivity of Shiga Toxin-Converting Bacteriophage Virions Φ24B, 933W, P22, P27 and P32

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    Sylwia Bloch

    2015-09-01

    Full Text Available Shiga toxin-converting bacteriophages (Stx phages are present as prophages in Shiga toxin-producing Escherichia coli (STEC strains. Theses phages can be transmitted to previously non-pathogenic E. coli cells making them potential producers of Shiga toxins, as they bear genes for these toxins in their genomes. Therefore, sensitivity of Stx phage virions to various conditions is important in both natural processes of spreading of these viruses and potential prophylactic control of appearance of novel pathogenic E. coli strains. In this report we provide evidence that virions of Stx phages are significantly more sensitive to UV irradiation than bacteriophage λ. Following UV irradiation of Stx virions at the dose of 50 J/m2, their infectivity dropped by 1–3 log10, depending on the kind of phage. Under these conditions, a considerable release of phage DNA from virions was observed, and electron microscopy analyses indicated a large proportion of partially damaged virions. Infection of E. coli cells with UV-irradiated Stx phages resulted in significantly decreased levels of expression of N and cro genes, crucial for lytic development. We conclude that inactivation of Stx virions caused by relatively low dose of UV light is due to damage of capsids that prevents effective infection of the host cells.

  2. Structural Characterization of H-1 Parvovirus: Comparison of Infectious Virions to Empty Capsids

    Science.gov (United States)

    Halder, Sujata; Nam, Hyun-Joo; Govindasamy, Lakshmanan; Vogel, Michèle; Dinsart, Christiane; Salomé, Nathalie; McKenna, Robert

    2013-01-01

    The structure of single-stranded DNA (ssDNA) packaging H-1 parvovirus (H-1PV), which is being developed as an antitumor gene delivery vector, has been determined for wild-type (wt) virions and noninfectious (empty) capsids to 2.7- and 3.2-Å resolution, respectively, using X-ray crystallography. The capsid viral protein (VP) structure consists of an α-helix and an eight-stranded anti-parallel β-barrel with large loop regions between the strands. The β-barrel and loops form the capsid core and surface, respectively. In the wt structure, 600 nucleotides are ordered in an interior DNA binding pocket of the capsid. This accounts for ∼12% of the H-1PV genome. The wt structure is identical to the empty capsid structure, except for side chain conformation variations at the nucleotide binding pocket. Comparison of the H-1PV nucleotides to those observed in canine parvovirus and minute virus of mice, two members of the genus Parvovirus, showed both similarity in structure and analogous interactions. This observation suggests a functional role, such as in capsid stability and/or ssDNA genome recognition for encapsulation. The VP structure differs from those of other parvoviruses in surface loop regions that control receptor binding, tissue tropism, pathogenicity, and antibody recognition, including VP sequences reported to determine tumor cell tropism for oncotropic rodent parvoviruses. These structures of H-1PV provide insight into structural features that dictate capsid stabilization following genome packaging and three-dimensional information applicable for rational design of tumor-targeted recombinant gene delivery vectors. PMID:23449783

  3. Enterovirus 71 virion-associated galectin-1 facilitates viral replication and stability.

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    Pei-Huan Lee

    Full Text Available Enterovirus 71 (EV71 infection causes a myriad of diseases from mild hand-foot-and-mouth disease or herpangina to fatal brain stem encephalitis complicated with pulmonary edema. Several severe EV71 endemics have occurred in Asia-Pacific region, including Taiwan, and have become a serious threat to children's health. EV71 infection is initiated by the attachment of the virion to the target cell surface. Although this process relies primarily upon interaction between viruses and cell surface receptors, soluble factors may also influence the binding of EV71 to host cells. Galectin-1 has been reported to participate in several virus infections, but is not addressed in EV71. In this study, we found that the serum levels of galectin-1 in EV71-infected children were higher than those in non-infected people. In EV71 infected cells, galectin-1 was found to be associated with the EV71 VP1 and VP3 via carbohydrate residues and subsequently released and bound to another cell surface along with the virus. EV71 propagated from galectin-1 knockdown SK-N-SH cells exhibited lower infectivity in cultured cells and less pathogenicity in mice than the virus propagated from parental cells. In addition, this galectin-1-free EV71 virus was sensitive to high temperature and lost its viability after long-term storage, which could be restored following supplement of recombinant galectin-1. Taken together, our findings uncover a new role of galectin-1 in facilitating EV71 virus infection.

  4. Evidence for translational regulation by the herpes simplex virus virion host shutoff protein.

    Science.gov (United States)

    Saffran, Holly A; Read, G Sullivan; Smiley, James R

    2010-06-01

    The herpes simplex virus (HSV) virion host shutoff protein (vhs) encoded by gene UL41 is an mRNA-specific RNase that triggers accelerated degradation of host and viral mRNAs in infected cells. We report here that vhs is also able to modulate reporter gene expression without greatly altering the levels of the target mRNA in transient-transfection assays conducted in HeLa cells. We monitored the effects of vhs on a panel of bicistronic reporter constructs bearing a variety of internal ribosome entry sites (IRESs) located between two test cistrons. As expected, vhs inhibited the expression of the 5' cistrons of all of these constructs; however, the response of the 3' cistron varied with the IRES: expression driven from the wild-type EMCV IRES was strongly suppressed, while expression controlled by a mutant EMCV IRES and the cellular ApaF1, BiP, and DAP5 IRES elements was strongly activated. In addition, several HSV type 1 (HSV-1) 5' untranslated region (5' UTR) sequences also served as positive vhs response elements in this assay. IRES activation was also observed in 293 and HepG2 cells, but no such response was observed in Vero cells. Mutational analysis has yet to uncouple the ability of vhs to activate 3' cistron expression from its shutoff activity. Remarkably, repression of 5' cistron expression could be observed under conditions where the levels of the reporter RNA were not correspondingly reduced. These data provide strong evidence that vhs can modulate gene expression at the level of translation and that it is able to activate cap-independent translation through specific cis-acting elements.

  5. The T7-related Pseudomonas putida phage φ15 displays virion-associated biofilm degradation properties.

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    Anneleen Cornelissen

    Full Text Available Formation of a protected biofilm environment is recognized as one of the major causes of the increasing antibiotic resistance development and emphasizes the need to develop alternative antibacterial strategies, like phage therapy. This study investigates the in vitro degradation of single-species Pseudomonas putida biofilms, PpG1 and RD5PR2, by the novel phage ϕ15, a 'T7-like virus' with a virion-associated exopolysaccharide (EPS depolymerase. Phage ϕ15 forms plaques surrounded by growing opaque halo zones, indicative for EPS degradation, on seven out of 53 P. putida strains. The absence of haloes on infection resistant strains suggests that the EPS probably act as a primary bacterial receptor for phage infection. Independent of bacterial strain or biofilm age, a time and dose dependent response of ϕ15-mediated biofilm degradation was observed with generally a maximum biofilm degradation 8 h after addition of the higher phage doses (10(4 and 10(6 pfu and resistance development after 24 h. Biofilm age, an in vivo very variable parameter, reduced markedly phage-mediated degradation of PpG1 biofilms, while degradation of RD5PR2 biofilms and ϕ15 amplification were unaffected. Killing of the planktonic culture occurred in parallel with but was always more pronounced than biofilm degradation, accentuating the need for evaluating phages for therapeutic purposes in biofilm conditions. EPS degrading activity of recombinantly expressed viral tail spike was confirmed by capsule staining. These data suggests that the addition of high initial titers of specifically selected phages with a proper EPS depolymerase are crucial criteria in the development of phage therapy.

  6. Herpes simplex virus types 1 and 2 induce shutoff of host protein synthesis by different mechanisms in Friend erythroleukemia cells.

    Science.gov (United States)

    Hill, T M; Sinden, R R; Sadler, J R

    1983-01-01

    Herpes simplex virus type 1 (HSV-1) and HSV-2 disrupt host protein synthesis after viral infection. We have treated both viral types with agents which prevent transcription of the viral genome and used these treated viruses to infect induced Friend erythroleukemia cells. By measuring the changes in globin synthesis after infection, we have determined whether expression of the viral genome precedes the shutoff of host protein synthesis or whether the inhibitor molecule enters the cells as part of the virion. HSV-2-induced shutoff of host protein synthesis was insensitive to the effects of shortwave (254-nm) UV light and actinomycin D. Both of the treatments inhibited HSV-1-induced host protein shutoff. Likewise, treatment of HSV-1 with the cross-linking agent 4,5',8-trimethylpsoralen and longwave (360-nm) UV light prevented HSV-1 from inhibiting cellular protein synthesis. Treatment of HSV-2 with 4,5',8-trimethylpsoralen did not affect the ability of the virus to interfere with host protein synthesis, except at the highest doses of longwave UV light. It was determined that the highest longwave UV dosage damaged the HSV-2 virion as well as cross-linking the viral DNA. The results suggest that HSV-2 uses a virion-associated component to inhibit host protein synthesis and that HSV-1 requires the expression of the viral genome to cause cellular protein synthesis shutoff.

  7. Lymphotropic Virions Affect Chemokine Receptor-Mediated Neural Signaling and Apoptosis: Implications for Human Immunodeficiency Virus Type 1-Associated Dementia

    Science.gov (United States)

    Zheng, Jialin; Ghorpade, Anuja; Niemann, Douglas; Cotter, Robin L.; Thylin, Michael R.; Epstein, Leon; Swartz, Jennifer M.; Shepard, Robin B.; Liu, Xiaojuan; Nukuna, Adeline; Gendelman, Howard E.

    1999-01-01

    Chemokine receptors pivotal for human immunodeficiency virus type 1 (HIV-1) infection in lymphocytes and macrophages (CCR3, CCR5, and CXCR4) are expressed on neural cells (microglia, astrocytes, and/or neurons). It is these cells which are damaged during progressive HIV-1 infection of the central nervous system. We theorize that viral coreceptors could effect neural cell damage during HIV-1-associated dementia (HAD) without simultaneously affecting viral replication. To these ends, we studied the ability of diverse viral strains to affect intracellular signaling and apoptosis of neurons, astrocytes, and monocyte-derived macrophages. Inhibition of cyclic AMP, activation of inositol 1,4,5-trisphosphate, and apoptosis were induced by diverse HIV-1 strains, principally in neurons. Virions from T-cell-tropic (T-tropic) strains (MN, IIIB, and Lai) produced the most significant alterations in signaling of neurons and astrocytes. The HIV-1 envelope glycoprotein, gp120, induced markedly less neural damage than purified virions. Macrophage-tropic (M-tropic) strains (ADA, JR-FL, Bal, MS-CSF, and DJV) produced the least neural damage, while 89.6, a dual-tropic HIV-1 strain, elicited intermediate neural cell damage. All T-tropic strain-mediated neuronal impairments were blocked by the CXCR4 antibody, 12G5. In contrast, the M-tropic strains were only partially blocked by 12G5. CXCR4-mediated neuronal apoptosis was confirmed in pure populations of rat cerebellar granule neurons and was blocked by HA1004, an inhibitor of calcium/calmodulin-dependent protein kinase II, protein kinase A, and protein kinase C. Taken together, these results suggest that progeny HIV-1 virions can influence neuronal signal transduction and apoptosis. This process occurs, in part, through CXCR4 and is independent of CD4 binding. T-tropic viruses that traffic in and out of the brain during progressive HIV-1 disease may play an important role in HAD neuropathogenesis. PMID:10482576

  8. Extensive in silico analysis of Mimivirus coded Rab GTPase homolog suggests a possible role in virion membrane biogenesis

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    Amrutraj eZade

    2015-09-01

    Full Text Available Rab GTPases are the key regulators of intracellular membrane trafficking in eukaryotes. Many viruses and intracellular bacterial pathogens have evolved to hijack the host Rab GTPase functions, mainly through activators and effector proteins, for their benefit. Acanthamoeba polyphaga mimivirus (APMV is one of the largest viruses and belongs to the monophyletic clade of nucleo-cytoplasmic large DNA viruses (NCLDV. The inner membrane lining is integral to the APMV virion structure. APMV assembly involves extensive host membrane modifications, like vesicle budding and fusion, leading to the formation of a membrane sheet that is incorporated into the virion. Intriguingly, APMV and all group I members of the Mimiviridae family code for a putative Rab GTPase protein. APMV is the first reported virus to code for a Rab GTPase (encoded by R214 gene. Our thorough in silico analysis of the subfamily specific (SF region of Mimiviridae Rab GTPase sequences suggests that they are related to Rab5, a member of the group II Rab GTPases, of lower eukaryotes. Because of their high divergence from the existing three isoforms, A, B and C of the Rab5-family, we suggest that Mimiviridae Rabs constitute a new isoform, Rab5D. Phylogenetic analysis indicated probable horizontal acquisition from a lower eukaryotic ancestor followed by selection and divergence. Furthermore, interaction network analysis suggests that vps34 (a Class III P13K homolog, coded by APMV L615, Atg-8 and dynamin (host proteins are recruited by APMV Rab GTPase during capsid assembly. Based on these observations, we hypothesize that APMV Rab plays a role in the acquisition of inner membrane during virion assembly.

  9. Fusion between perinuclear virions and the outer nuclear membrane requires the fusogenic activity of herpes simplex virus gB.

    Science.gov (United States)

    Wright, Catherine C; Wisner, Todd W; Hannah, Brian P; Eisenberg, Roselyn J; Cohen, Gary H; Johnson, David C

    2009-11-01

    Herpesviruses cross nuclear membranes (NMs) in two steps, as follows: (i) capsids assemble and bud through the inner NM into the perinuclear space, producing enveloped virus particles, and (ii) the envelopes of these virus particles fuse with the outer NM. Two herpes simplex virus (HSV) glycoproteins, gB and gH (the latter, likely complexed as a heterodimer with gL), are necessary for the second step of this process. Mutants lacking both gB and gH accumulate in the perinuclear space or in herniations (membrane vesicles derived from the inner NM). Both gB and gH/gL are also known to act directly in fusing the virion envelope with host cell membranes during HSV entry into cells, i.e., both glycoproteins appear to function directly in different aspects of the membrane fusion process. We hypothesized that HSV gB and gH/gL also act directly in the membrane fusion that occurs during virus egress from the nucleus. Previous studies of the role of gB and gH/gL in nuclear egress involved HSV gB and gH null mutants that could potentially also possess gross defects in the virion envelope. Here, we produced recombinant HSV-expressing mutant forms of gB with single amino acid substitutions in the hydrophobic "fusion loops." These fusion loops are thought to play a direct role in membrane fusion by insertion into cellular membranes. HSV recombinants expressing gB with any one of four fusion loop mutations (W174R, W174Y, Y179K, and A261D) were unable to enter cells. Moreover, two of the mutants, W174Y and Y179K, displayed reduced abilities to mediate HSV cell-to-cell spread, and W174R and A261D exhibited no spread. All mutant viruses exhibited defects in nuclear egress, enveloped virions accumulated in herniations and in the perinuclear space, and fewer enveloped virions were detected on cell surfaces. These results support the hypothesis that gB functions directly to mediate the fusion between perinuclear virus particles and the outer NM.

  10. Secretion of genome-free hepatitis B virus--single strand blocking model for virion morphogenesis of para-retrovirus.

    OpenAIRE

    Xiaojun Ning; David Nguyen; Laura Mentzer; Christina Adams; Hyunwook Lee; Robert Ashley; Susan Hafenstein; Jianming Hu

    2011-01-01

    As a para-retrovirus, hepatitis B virus (HBV) is an enveloped virus with a double-stranded (DS) DNA genome that is replicated by reverse transcription of an RNA intermediate, the pregenomic RNA or pgRNA. HBV assembly begins with the formation of an “immature” nucleocapsid (NC) incorporating pgRNA, which is converted via reverse transcription within the maturing NC to the DS DNA genome. Only the mature, DS DNA-containing NCs are enveloped and secreted as virions whereas immature NCs containing...

  11. Single particle analysis of herpes simplex virus: comparing the dimensions of one and the same virions via atomic force and scanning electron microscopy.

    Science.gov (United States)

    Kämmer, Evelyn; Götz, Isabell; Bocklitz, Thomas; Stöckel, Stephan; Dellith, Andrea; Cialla-May, Dana; Weber, Karina; Zell, Roland; Dellith, Jan; Deckert, Volker; Popp, Jürgen

    2016-06-01

    Currently, two types of direct methods to characterize and identify single virions are available: electron microscopy (EM) and scanning probe techniques, especially atomic force microscopy (AFM). AFM in particular provides morphologic information even of the ultrastructure of viral specimens without the need to cultivate the virus and to invasively alter the sample prior to the measurements. Thus, AFM can play a critical role as a frontline method in diagnostic virology. Interestingly, varying morphological parameters for virions of the same type can be found in the literature, depending on whether AFM or EM was employed and according to the respective experimental conditions during the AFM measurements. Here, an inter-methodological proof of principle is presented, in which the same single virions of herpes simplex virus 1 were probed by AFM previously and after they were measured by scanning electron microscopy (SEM). Sophisticated chemometric analyses then allowed a calculation of morphological parameters of the ensemble of single virions and a comparison thereof. A distinct decrease in the virions' dimensions was found during as well as after the SEM analyses and could be attributed to the sample preparation for the SEM measurements. Graphical abstract The herpes simplex virus is investigated with scanning electron and atomic force microscopy in view of varying dimensions.

  12. Modeling of Virion Collisions in Cervicovaginal Mucus Reveals Limits on Agglutination as the Protective Mechanism of Secretory Immunoglobulin A.

    Science.gov (United States)

    Chen, Alex; McKinley, Scott A; Shi, Feng; Wang, Simi; Mucha, Peter J; Harit, Dimple; Forest, M Gregory; Lai, Samuel K

    2015-01-01

    Secretory immunoglobulin A (sIgA), a dimeric antibody found in high quantities in the gastrointestinal mucosa, is broadly associated with mucosal immune protection. A distinguishing feature of sIgA is its ability to crosslink pathogens, thereby creating pathogen/sIgA aggregates that are too large to traverse the dense matrix of mucin fibers in mucus layers overlying epithelial cells and consequently reducing infectivity. Here, we use modeling to investigate this mechanism of "immune exclusion" based on sIgA-mediated agglutination, in particular the potential use of sIgA to agglutinate HIV in cervicovaginal mucus (CVM) and prevent HIV transmission. Utilizing reported data on HIV diffusion in CVM and semen, we simulate HIV collision kinetics in physiologically-thick mucus layers-a necessary first step for sIgA-induced aggregation. We find that even at the median HIV load in semen of acutely infected individuals possessing high viral titers, over 99% of HIV virions will penetrate CVM and reach the vaginal epithelium without colliding with another virion. These findings imply that agglutination is unlikely to be the dominant mechanism of sIgA-mediated protection against HIV or other sexually transmitted pathogens. Rather, we surmise that agglutination is most effective against pathogens either present at exceedingly high concentrations or that possess motility mechanisms other than Brownian diffusion that significantly enhance encounter rates.

  13. Abortive replication of Bombyx mori nucleopolyhedrovirus in Sf9 and High Five cells: defective nuclear transport of the virions.

    Science.gov (United States)

    Katou, Yasuhiro; Ikeda, Motoko; Kobayashi, Michihiro

    2006-04-10

    Despite close genetic relationship, Bombyx mori nucleopolyhedrovirus (BmNPV) and Autographa californica multicapsid NPV (AcMNPV) display a distinct host range property. Here, BmNPV replication was examined in Sf9 and High Five cells that were nonproductive for BmNPV infection but supported high titers of AcMNPV replication. Recombinant BmNPV, vBm/gfp/lac, containing bm-ie1 promoter-driven egfp showed that few Sf9 and High Five cells infected with vBm/gfp/lac expressed EGFP, while large proportion of EGFP-expressing cells was observed when transfected with vBm/gfp/lac DNA. Immunocytochemical analysis showed that BmNPV was not imported into the nucleus of these two cell lines, while recombinant BmNPV, vBmDelta64/ac-gp64 possessing AcMNPV gp64 was imported into the nucleus, yielding progeny virions in High Five cells, but not Sf9 cells. These results indicate that the defective nuclear import of infected virions due to insufficient BmNPV GP64 function is involved in the restricted BmNPV replication in Sf9 and High Five cells.

  14. Differential Expression of HERV-K (HML-2) Proviruses in Cells and Virions of the Teratocarcinoma Cell Line Tera-1

    Science.gov (United States)

    Bhardwaj, Neeru; Montesion, Meagan; Roy, Farrah; Coffin, John M.

    2015-01-01

    Human endogenous retrovirus (HERV-K (HML-2)) proviruses are among the few endogenous retroviral elements in the human genome that retain coding sequence. HML-2 expression has been widely associated with human disease states, including different types of cancers as well as with HIV-1 infection. Understanding of the potential impact of this expression requires that it be annotated at the proviral level. Here, we utilized the high throughput capabilities of next-generation sequencing to profile HML-2 expression at the level of individual proviruses and secreted virions in the teratocarcinoma cell line Tera-1. We identified well-defined expression patterns, with transcripts emanating primarily from two proviruses located on chromosome 22, only one of which was efficiently packaged. Interestingly, there was a preference for transcripts of recently integrated proviruses, over those from other highly expressed but older elements, to be packaged into virions. We also assessed the promoter competence of the 5’ long terminal repeats (LTRs) of expressed proviruses via a luciferase assay following transfection of Tera-1 cells. Consistent with the RNASeq results, we found that the activity of most LTRs corresponded to their transcript levels. PMID:25746218

  15. Differential expression of HERV-K (HML-2) proviruses in cells and virions of the teratocarcinoma cell line Tera-1.

    Science.gov (United States)

    Bhardwaj, Neeru; Montesion, Meagan; Roy, Farrah; Coffin, John M

    2015-03-04

    Human endogenous retrovirus (HERV-K (HML-2)) proviruses are among the few endogenous retroviral elements in the human genome that retain coding sequence. HML-2 expression has been widely associated with human disease states, including different types of cancers as well as with HIV-1 infection. Understanding of the potential impact of this expression requires that it be annotated at the proviral level. Here, we utilized the high throughput capabilities of next-generation sequencing to profile HML-2 expression at the level of individual proviruses and secreted virions in the teratocarcinoma cell line Tera-1. We identified well-defined expression patterns, with transcripts emanating primarily from two proviruses located on chromosome 22, only one of which was efficiently packaged. Interestingly, there was a preference for transcripts of recently integrated proviruses, over those from other highly expressed but older elements, to be packaged into virions. We also assessed the promoter competence of the 5' long terminal repeats (LTRs) of expressed proviruses via a luciferase assay following transfection of Tera-1 cells. Consistent with the RNASeq results, we found that the activity of most LTRs corresponded to their transcript levels.

  16. Estimating the fraction of progeny virions that must incorporate APOBEC3G for suppression of productive HIV-1 infection

    Energy Technology Data Exchange (ETDEWEB)

    Thangavelu, Pulari U.; Gupta, Vipul; Dixit, Narendra M., E-mail: narendra@chemeng.iisc.ernet.in

    2014-01-20

    The contest between the host factor APOBEC3G (A3G) and the HIV-1 protein Vif presents an attractive target of intervention. The extent to which the A3G–Vif interaction must be suppressed to tilt the balance in favor of A3G remains unknown. We employed stochastic simulations and mathematical modeling of the within-host dynamics and evolution of HIV-1 to estimate the fraction of progeny virions that must incorporate A3G to render productive infection unsustainable. Using three different approaches, we found consistently that a transition from sustained infection to suppression of productive infection occurred when the latter fraction exceeded ∼0.8. The transition was triggered by A3G-induced hypermutations that led to premature stop codons compromising viral production and was consistent with driving the basic reproductive number, R{sub 0}, below unity. The fraction identified may serve as a quantitative guideline for strategies targeting the A3G–Vif axis. - Highlights: • We perform simulations and mathematical modeling of the role of APOBEC3G in suppressing HIV-1 infection. • In three distinct ways, we estimate that when over 80% of progeny virions carry APOBEC3G, productive HIV-1 infection would be suppressed. • Our estimate of this critical fraction presents quantitative guidelines for strategies targeting the APOBEC3G–Vif axis.

  17. Liposomal leakage induced by virus-derived peptides, viral proteins, and entire virions: rapid analysis by chip electrophoresis.

    Science.gov (United States)

    Weiss, Victor U; Bilek, Gerhard; Pickl-Herk, Angela; Subirats, Xavier; Niespodziana, Katarzyna; Valenta, Rudolf; Blaas, Dieter; Kenndler, Ernst

    2010-10-01

    Permeabilization of model lipid membranes by virus-derived peptides, viral proteins, and entire virions of human rhinovirus was assessed by quantifying the release of a fluorescent dye from liposomes via a novel chip electrophoretic assay. Liposomal leakage readily occurred upon incubation with the pH-sensitive synthetic fusogenic peptide GALA and, less efficiently, with a 24mer peptide (P1-N) derived from the N-terminus of the capsid protein VP1 of human rhinovirus 2 (HRV2) at acidic pH. Negative stain transmission electron microscopy showed that liposomes incubated with the rhinovirus-derived peptide remained largely intact. At similar concentrations, the GALA peptide caused gross morphological changes of the liposomes. On a molar basis, the leakage-inducing efficiency of the P1 peptide was by about 2 orders of magnitude inferior to that of recombinant VP1 (from HRV89) and entire HRV2. This underscores the role in membrane destabilization of VP1 domains remote from the N-terminus and the arrangement of the peptide in the context of the icosahedral virion. Our method is rapid, requires tiny amounts of sample, and allows for the parallel determination of released and retained liposomal cargo.

  18. Differential Expression of HERV-K (HML-2 Proviruses in Cells and Virions of the Teratocarcinoma Cell Line Tera-1

    Directory of Open Access Journals (Sweden)

    Neeru Bhardwaj

    2015-03-01

    Full Text Available Human endogenous retrovirus (HERV-K (HML-2 proviruses are among the few endogenous retroviral elements in the human genome that retain coding sequence. HML-2 expression has been widely associated with human disease states, including different types of cancers as well as with HIV-1 infection. Understanding of the potential impact of this expression requires that it be annotated at the proviral level. Here, we utilized the high throughput capabilities of next-generation sequencing to profile HML-2 expression at the level of individual proviruses and secreted virions in the teratocarcinoma cell line Tera-1. We identified well-defined expression patterns, with transcripts emanating primarily from two proviruses located on chromosome 22, only one of which was efficiently packaged. Interestingly, there was a preference for transcripts of recently integrated proviruses, over those from other highly expressed but older elements, to be packaged into virions. We also assessed the promoter competence of the 5’ long terminal repeats (LTRs of expressed proviruses via a luciferase assay following transfection of Tera-1 cells. Consistent with the RNASeq results, we found that the activity of most LTRs corresponded to their transcript levels.

  19. A viable simian virus 40 variant with a deletion in the overlapping genes for virion proteins VP1, VP2 and VP3.

    Science.gov (United States)

    Norkin, L C; Piatak, M

    1982-12-01

    Nucleotide sequence analysis was used to determine the exact location of a deletion in the late region of the SP2 mutant of simian virus 40 (SV40), a viable small-plaque variant isolated from a persistent infection of rhesus monkey kidney cells. The results indicate that six base pairs are deleted from that part of the SV40 genome in which the coding regions for the three virion proteins, VP1, VP2 and VP3, overlap. This implies that all three virion proteins are affected by the deletion. This finding is discussed with respect to the viability of SP2.

  20. Myristoylation of the Arenavirus Envelope Glycoprotein Stable Signal Peptide Is Critical for Membrane Fusion but Dispensable for Virion Morphogenesis

    Science.gov (United States)

    York, Joanne

    2016-01-01

    ABSTRACT Arenaviruses are responsible for severe and often fatal hemorrhagic disease. In the absence of effective antiviral therapies and vaccines, these viruses pose serious threats to public health and biodefense. Arenaviruses enter the host cell by fusion of the viral and endosomal membranes, a process mediated by the virus envelope glycoprotein GPC. Unlike other class I viral fusion proteins, GPC retains its stable signal peptide (SSP) as an essential third subunit in the mature complex. SSP spans the membrane twice and is myristoylated at its cytoplasmic N terminus. Mutations that abolish SSP myristoylation have been shown to reduce pH-induced cell-cell fusion activity of ectopically expressed GPC to ∼20% of wild-type levels. In order to examine the role of SSP myristoylation in the context of the intact virus, we used reverse genetics to generate Junín viruses (Candid #1 isolate) in which the critical glycine-2 residue in SSP was either replaced by alanine (G2A) or deleted (ΔG2). These mutant viruses produced smaller foci of infection in Vero cells and showed an ∼5-fold reduction in specific infectivity, commensurate with the defect in cell-cell fusion. However, virus assembly and GPC incorporation into budded virions were unaffected. Our findings suggest that the myristate moiety is cryptically disposed in the prefusion GPC complex and may function late in the fusion process to promote merging of the viral and cellular membranes. IMPORTANCE Hemorrhagic fever arenaviruses pose significant threats to public health and biodefense. Arenavirus entry into the host cell is promoted by the virus envelope glycoprotein GPC. Unlike other viral envelope glycoproteins, GPC contains a myristoylated stable signal peptide (SSP) as an essential third subunit. Myristoylation has been shown to be important for the membrane fusion activity of recombinantly expressed GPC. Here, we use reverse genetics to study the role of SSP myristoylation in the context of the intact

  1. A new approach for sequencing virion genome of Chinese HIV-1 strains subtype B and BC from plasma

    Institute of Scientific and Technical Information of China (English)

    MENG Zhe-feng; ZHANG Xiao-yan; XIN Ruo-lei; XING Hui; HE Xiang; XU Jian-qing; SHAO Yi-ming

    2011-01-01

    Background Although it was widely accepted that full-length HIV genome sequences is important in studying virus genetic evolution and variation as well as developing vaccine candidate,to directly sequencing HIV-1 genome of virion RNA remains as a challenge worldwide.Up to date,no published genomic sequences from virion RNA are available for Chinese prevalent HIV-1 strains due to the absence of specialized protocol and appropriate lab equipments.In this study we developed a straightforward approach for amplifying and sequencing HIV virion RNA from plasma by modifying published protocols and further confirmed it is suitable to process Chinese samples.Methods The methods for viral RNA extraction and gene amplification was modified and optimized as could be widely used in most Chinese labs.Gene alignment of Chinese HIV-1 strains was employed for designing specialized primer sets for Thai-B and BC recombinant strains.Based on comprehensively consideration of high variable gene region and recombinant breakpoints in BC recombinant strains,a three-amplicon strategy (including 4.3-kb gag-pol,2.9-kb pol-env and 2.7-kb env-ne) was developed.In addition,one amplicon (9 kb near full-length genome) was also used in 32 samples with varied viral loads.All amplicons were directly sequenced by DNA automated sequencer.Results Twenty-five percent(8/32) amplification efficiency was achieved by the one-amplicon strategy and 65.6%(21/32) by three-amplicon strategy.For one amplicon strategy,none of complete near full-length genome sequences was obtained by DNA sequencing.For three-amplicon strategy,75% sequences were achieved in DNA sequencing.Amplification efficiency but not sequencing efficiency was closely associated with viral loads.Conclusion Three-amplicon strategy covering all encoding regions of HIV-1 is suitable for Thai-B and BC recombinant strains and could be potentially employed in less-well equipped Chinese labs.

  2. The UL41-encoded virion host shutoff (vhs) protein and vhs-independent mechanisms are responsible for down-regulation of MHC class I molecules by bovine herpesvirus 1.

    Science.gov (United States)

    Koppers-Lalic, D; Rijsewijk, F A; Verschuren, S B; van Gaans-Van den Brink, J A; Neisig, A; Ressing, M E; Neefjes, J; Wiertz, E J

    2001-09-01

    The virion host shutoff (vhs) protein of alphaherpesviruses causes a rapid shutoff of host cell protein synthesis. We constructed a bovine herpesvirus 1 (BHV1) deletion mutant in which the putative vhs gene, UL41, has been disrupted. Whereas protein synthesis is inhibited within 3 h after infection with wild-type BHV1, no inhibition was observed after infection with the BHV1(vhs-) deletion mutant. These results indicate that the BHV1 UL41 gene product is both necessary and sufficient for shutoff of host cell protein synthesis at early times post-infection. Using the vhs deletion mutant, we investigated the mechanism of BHV1-induced down-regulation of MHC class I cell surface expression. In contrast to BHV1 wild-type infection, the BHV1(vhs-) mutant allows detection of MHC class I molecules at much later time-points after infection. This illustrates the role the vhs protein plays in MHC class I down-regulation. However, even after infection with BHV1(vhs-), MHC class I cell surface expression is impaired. In BHV1(vhs-)-infected cells, MHC class I molecules are retained within the endoplasmic reticulum (ER). Moreover, the transporter associated with antigen presentation (TAP) is still blocked. Temporal control of viral protein expression using chemical inhibitors shows that viral protein(s) expressed within the early phase of BHV1 infection are responsible for ER retention of MHC class I molecules. These results indicate that multiple mechanisms are responsible for down-regulation of MHC class I molecules in BHV1-infected cells.

  3. y Human herpesvirus 6 envelope components enriched in lipid rafts: evidence for virion-associated lipid rafts

    Directory of Open Access Journals (Sweden)

    Yamanishi Koichi

    2009-08-01

    Full Text Available Abstract In general, enveloped viruses are highly dependent on their lipid envelope for entry into host cells. Here, we demonstrated that during the course of virus maturation, a significant proportion of human herpesvirus 6 (HHV-6 envelope proteins were selectively concentrated in the detergent-resistant glycosphingolipid- and cholesterol-rich membranes (rafts in HHV-6-infected cells. In addition, the ganglioside GM1, which is known to partition preferentially into lipid rafts, was detected in purified virions, along with viral envelope glycoproteins, gH, gL, gB, gQ1, gQ2 and gO indicating that at least one raft component was included in the viral particle during the assembly process.

  4. Solubilization of matrix protein M1/M from virions occurs at different pH for orthomyxo- and paramyxoviruses.

    Science.gov (United States)

    Zhirnov, O P

    1990-05-01

    Enveloped viruses, of which the orthomyxo- and paramyxoviruses are members, are known to be uncoated by nonionic detergents in a salt concentration-dependent manner. In this study we have shown that detergent uncoating of myxoviruses depends not only on salt concentration but also on pH. Treatment of orthomyxoviruses with Nonidet-P40 or Triton N-101 at low salt concentrations results in solubilization of surface virion glycopolypeptides in alkaline and neutral pH (9.0-6.5), but in acidic pH (6.0-5.0) the viral matrix protein M1 is also removed, and the viral ribonucleoprotein complex is released. Conversely, the paramyxovirus matrix protein M is more completely solubilized in alkaline pH (pH 9.0) than in neutral and acidic pH 7.4-5.0. The described pH-dependent differences are discussed in terms of orthomyxo- and paramyxovirus uncoating in target cells.

  5. Dextran Sulfate Suppression of Viruses in the HIV Family: Inhibition of Virion Binding to CD4+ Cells

    Science.gov (United States)

    Mitsuya, Hiroaki; Looney, David J.; Kuno, Sachiko; Ueno, Ryuji; Wong-Staal, Flossie; Broder, Samuel

    1988-04-01

    The first step in the infection of human T lymphocytes by human immunodeficiency virus type 1 (HIV-1) is attachment to the target cell receptor, the CD4 antigen. This step may be vulnerable to attack by antibodies, chemicals, or small peptides. Dextran sulfate (molecular weight approximately 8000), which has been given to patients as an anticoagulant or antilipemic agent for more than two decades, was found to block the binding of virions to various target T lymphocytes, inhibit syncytia formation, and exert a potent inhibitory effect against HIV-1 in vitro at concentrations that may be clinically attainable in human beings. This drug also suppressed the replication of HIV-2 in vitro. These observations could have theoretical and clinical implications in the strategy to develop drugs against HIV types 1 and 2.

  6. Detection of Receptor-Induced Glycoprotein Conformational Changes on Enveloped Virions by Using Confocal Micro-Raman Spectroscopy

    Science.gov (United States)

    Lu, Xiaonan; Liu, Qian; Benavides-Montano, Javier A.; Nicola, Anthony V.; Aston, D. Eric; Rasco, Barbara A.

    2013-01-01

    Conformational changes in the glycoproteins of enveloped viruses are critical for membrane fusion, which enables viral entry into cells and the pathological cell-cell fusion (syncytia) associated with some viral infections. However, technological capabilities for identifying viral glycoproteins and their conformational changes on actual enveloped virus surfaces are generally scarce, challenging, and time-consuming. Our model, Nipah virus (NiV), is a syncytium-forming biosafety level 4 pathogen with a high mortality rate (40 to 75%) in humans. Once the NiV attachment glycoprotein (G) (NiV-G) binds the cell receptor ephrinB2 or -B3, G triggers conformational changes in the fusion glycoprotein (F) that result in membrane fusion and viral entry. We demonstrate that confocal micro-Raman spectroscopy can, within minutes, simultaneously identify specific G and F glycoprotein signals and receptor-induced conformational changes in NiV-F on NiV virus-like particles (VLPs). First, we identified reproducible G- and F-specific Raman spectral features on NiV VLPs containing M (assembly matrix protein), G, and/or F or on NiV/vesicular stomatitis virus (VSV) pseudotyped virions via second-derivative transformations and principal component analysis (PCA). Statistical analyses validated our PCA models. Dynamic temperature-induced conformational changes in F and G or receptor-induced target membrane-dependent conformational changes in F were monitored in NiV pseudovirions in situ in real time by confocal micro-Raman spectroscopy. Advantageously, Raman spectroscopy can identify specific protein signals in relatively impure samples. Thus, this proof-of-principle technological development has implications for the rapid identification and biostability characterization of viruses in medical, veterinary, and food samples and for the analysis of virion glycoprotein conformational changes in situ during viral entry. PMID:23283947

  7. Vaccinia protein F12 has structural similarity to kinesin light chain and contains a motor binding motif required for virion export.

    Directory of Open Access Journals (Sweden)

    Gareth W Morgan

    2010-02-01

    Full Text Available Vaccinia virus (VACV uses microtubules for export of virions to the cell surface and this process requires the viral protein F12. Here we show that F12 has structural similarity to kinesin light chain (KLC, a subunit of the kinesin-1 motor that binds cargo. F12 and KLC share similar size, pI, hydropathy and cargo-binding tetratricopeptide repeats (TPRs. Moreover, molecular modeling of F12 TPRs upon the crystal structure of KLC2 TPRs showed a striking conservation of structure. We also identified multiple TPRs in VACV proteins E2 and A36. Data presented demonstrate that F12 is critical for recruitment of kinesin-1 to virions and that a conserved tryptophan and aspartic acid (WD motif, which is conserved in the kinesin-1-binding sequence (KBS of the neuronal protein calsyntenin/alcadein and several other cellular kinesin-1 binding proteins, is essential for kinesin-1 recruitment and virion transport. In contrast, mutation of WD motifs in protein A36 revealed they were not required for kinesin-1 recruitment or IEV transport. This report of a viral KLC-like protein containing a KBS that is conserved in several cellular proteins advances our understanding of how VACV recruits the kinesin motor to virions, and exemplifies how viruses use molecular mimicry of cellular components to their advantage.

  8. Urokinase plasminogen activator inhibits HIV virion release from macrophage-differentiated chronically infected cells via activation of RhoA and PKCε.

    Directory of Open Access Journals (Sweden)

    Francesca Graziano

    Full Text Available BACKGROUND: HIV replication in mononuclear phagocytes is a multi-step process regulated by viral and cellular proteins with the peculiar feature of virion budding and accumulation in intra-cytoplasmic vesicles. Interaction of urokinase-type plasminogen activator (uPA with its cell surface receptor (uPAR has been shown to favor virion accumulation in such sub-cellular compartment in primary monocyte-derived macrophages and chronically infected promonocytic U1 cells differentiated into macrophage-like cells by stimulation with phorbol myristate acetate (PMA. By adopting this latter model system, we have here investigated which intracellular signaling pathways were triggered by uPA/uPAR interaction leading the redirection of virion accumulation in intra-cytoplasmic vesicles. RESULTS: uPA induced activation of RhoA, PKCδ and PKCε in PMA-differentiated U1 cells. In the same conditions, RhoA, PKCδ and PKCε modulated uPA-induced cell adhesion and polarization, whereas only RhoA and PKCε were also responsible for the redirection of virions in intracellular vesicles. Distribution of G and F actin revealed that uPA reorganized the cytoskeleton in both adherent and polarized cells. The role of G and F actin isoforms was unveiled by the use of cytochalasin D, a cell-permeable fungal toxin that prevents F actin polymerization. Receptor-independent cytoskeleton remodeling by Cytochalasin D resulted in cell adhesion, polarization and intracellular accumulation of HIV virions similar to the effects gained with uPA. CONCLUSIONS: These findings illustrate the potential contribution of the uPA/uPAR system in the generation and/or maintenance of intra-cytoplasmic vesicles that actively accumulate virions, thus sustaining the presence of HIV reservoirs of macrophage origin. In addition, our observations also provide evidences that pathways controlling cytoskeleton remodeling and activation of PKCε bear relevance for the design of new antiviral strategies aimed

  9. Herpesvirus gB-induced fusion between the virion envelope and outer nuclear membrane during virus egress is regulated by the viral US3 kinase.

    Science.gov (United States)

    Wisner, Todd W; Wright, Catherine C; Kato, Akihisa; Kawaguchi, Yasushi; Mou, Fan; Baines, Joel D; Roller, Richard J; Johnson, David C

    2009-04-01

    Herpesvirus capsids collect along the inner surface of the nuclear envelope and bud into the perinuclear space. Enveloped virions then fuse with the outer nuclear membrane (NM). We previously showed that herpes simplex virus (HSV) glycoproteins gB and gH act in a redundant fashion to promote fusion between the virion envelope and the outer NM. HSV mutants lacking both gB and gH accumulate enveloped virions in herniations, vesicles that bulge into the nucleoplasm. Earlier studies had shown that HSV mutants lacking the viral serine/threonine kinase US3 also accumulate herniations. Here, we demonstrate that HSV gB is phosphorylated in a US3-dependent manner in HSV-infected cells, especially in a crude nuclear fraction. Moreover, US3 directly phosphorylated the gB cytoplasmic (CT) domain in in vitro assays. Deletion of gB in the context of a US3-null virus did not add substantially to defects in nuclear egress. The majority of the US3-dependent phosphorylation of gB involved the CT domain and amino acid T887, a residue present in a motif similar to that recognized by US3 in other proteins. HSV recombinants lacking gH and expressing either gB substitution mutation T887A or a gB truncated at residue 886 displayed substantial defects in nuclear egress. We concluded that phosphorylation of the gB CT domain is important for gB-mediated fusion with the outer NM. This suggested a model in which the US3 kinase is incorporated into the tegument layer (between the capsid and envelope) in HSV virions present in the perinuclear space. By this packaging, US3 might be brought close to the gB CT tail, leading to phosphorylation and triggering fusion between the virion envelope and the outer NM.

  10. Role of the virion host shutoff protein in neurovirulence of monkey B virus (Macacine herpesvirus 1).

    Science.gov (United States)

    Black, Darla; Ritchey, Jerry; Payton, Mark; Eberle, Richard

    2014-10-01

    Monkey B virus (Macacine herpesvirus 1; BV) is noted for its extreme neurovirulence in humans. Since the vhs protein encoded by the UL41 gene has been shown to be a neurovirulence factor in the related human herpes simplex viruses, the role of the UL41 gene in BV neurovirulence was investigated. BV mutants were constructed that lacked the entire UL41 ORF (Δ41) or had the RNase active site mutated (Δ41A). Neither mutant shut off host protein synthesis, degraded β-actin mRNA, or prevented an IFN-β response, indicating that the vhs protein and its RNase activity are both necessary for these activities. Replication of both mutants in primary mouse cells was impaired and they exhibited a prolonged disease course in mice. Whereas Δ41 infected mice were euthanized for symptoms related to central nervous system (CNS) infection, Δ41A infected mice were euthanized primarily for symptoms of autonomic nervous system dysfunction. While neuroinvasiveness was not affected, lesions in the CNS were more limited in size, anatomical distribution, and severity than for wild-type virus. These results indicate that the vhs protein affects the general replicative efficiency of BV in vivo rather than being a specific neurovirulence factor critical for invasion of or preferential replication in the CNS.

  11. The use of Nanotrap particles technology in capturing HIV-1 virions and viral proteins from infected cells.

    Directory of Open Access Journals (Sweden)

    Elizabeth Jaworski

    Full Text Available HIV-1 infection results in a chronic but incurable illness since long-term HAART can keep the virus to an undetectable level. However, discontinuation of therapy rapidly increases viral burden. Moreover, patients under HAART frequently develop various metabolic disorders and HIV-associated neuronal disease. Today, the main challenge of HIV-1 research is the elimination of the residual virus in infected individuals. The current HIV-1 diagnostics are largely comprised of serological and nucleic acid based technologies. Our goal is to integrate the nanotrap technology into a standard research tool that will allow sensitive detection of HIV-1 infection. This study demonstrates that majority of HIV-1 virions in culture supernatants and Tat/Nef proteins spiked in culture medium can be captured by nanotrap particles. To determine the binding affinities of different baits, we incubated target molecules with nanotrap particles at room temperature. After short sequestration, materials were either eluted or remained attached to nanotrap particles prior to analysis. The unique affinity baits of nanotrap particles preferentially bound HIV-1 materials while excluded albumin. A high level capture of Tat or Tat peptide by NT082 and NT084 particles was measured by western blot (WB. Intracellular Nef protein was captured by NT080, while membrane-associated Nef was captured by NT086 and also detected by WB. Selective capture of HIV-1 particles by NT073 and NT086 was measured by reverse transcriptase assay, while capture of infectious HIV-1 by these nanoparticles was demonstrated by functional transactivation in TZM-bl cells. We also demonstrated specific capture of HIV-1 particles and exosomes-containing TAR-RNA in patients' serum by NT086 and NT082 particles, respectively, using specific qRT-PCR. Collectively, our data indicate that certain types of nanotrap particles selectively capture specific HIV-1 molecules, and we propose to use this technology as a

  12. The Use of Nanotrap Particles Technology in Capturing HIV-1 Virions and Viral Proteins from Infected Cells

    Science.gov (United States)

    Sampey, Gavin; Shafagati, Nazly; Van Duyne, Rachel; Iordanskiy, Sergey; Kehn-Hall, Kylene; Liotta, Lance; Petricoin, Emanuel; Young, Mary; Lepene, Benjamin; Kashanchi, Fatah

    2014-01-01

    HIV-1 infection results in a chronic but incurable illness since long-term HAART can keep the virus to an undetectable level. However, discontinuation of therapy rapidly increases viral burden. Moreover, patients under HAART frequently develop various metabolic disorders and HIV-associated neuronal disease. Today, the main challenge of HIV-1 research is the elimination of the residual virus in infected individuals. The current HIV-1 diagnostics are largely comprised of serological and nucleic acid based technologies. Our goal is to integrate the nanotrap technology into a standard research tool that will allow sensitive detection of HIV-1 infection. This study demonstrates that majority of HIV-1 virions in culture supernatants and Tat/Nef proteins spiked in culture medium can be captured by nanotrap particles. To determine the binding affinities of different baits, we incubated target molecules with nanotrap particles at room temperature. After short sequestration, materials were either eluted or remained attached to nanotrap particles prior to analysis. The unique affinity baits of nanotrap particles preferentially bound HIV-1 materials while excluded albumin. A high level capture of Tat or Tat peptide by NT082 and NT084 particles was measured by western blot (WB). Intracellular Nef protein was captured by NT080, while membrane-associated Nef was captured by NT086 and also detected by WB. Selective capture of HIV-1 particles by NT073 and NT086 was measured by reverse transcriptase assay, while capture of infectious HIV-1 by these nanoparticles was demonstrated by functional transactivation in TZM-bl cells. We also demonstrated specific capture of HIV-1 particles and exosomes-containing TAR-RNA in patients' serum by NT086 and NT082 particles, respectively, using specific qRT-PCR. Collectively, our data indicate that certain types of nanotrap particles selectively capture specific HIV-1 molecules, and we propose to use this technology as a platform to enhance HIV-1

  13. Deletion of the Vaccinia Virus I2 Protein Interrupts Virion Morphogenesis, Leading to Retention of the Scaffold Protein and Mislocalization of Membrane-Associated Entry Proteins.

    Science.gov (United States)

    Hyun, Seong-In; Weisberg, Andrea; Moss, Bernard

    2017-08-01

    The I2L open reading frame of vaccinia virus (VACV) encodes a conserved 72-amino-acid protein with a putative C-terminal transmembrane domain. Previous studies with a tetracycline-inducible mutant demonstrated that I2-deficient virions are defective in cell entry. The purpose of the present study was to determine the step of replication or entry that is affected by loss of the I2 protein. Fluorescence microscopy experiments showed that I2 colocalized with a major membrane protein of immature and mature virions. We generated a cell line that constitutively expressed I2 and allowed construction of the VACV I2L deletion mutant vΔI2. As anticipated, vΔI2 was unable to replicate in cells that did not express I2. Unexpectedly, morphogenesis was interrupted at a stage after immature virion formation, resulting in the accumulation of dense spherical particles instead of brick-shaped mature virions with well-defined core structures. The abnormal particles retained the D13 scaffold protein of immature virions, were severely deficient in the transmembrane proteins that comprise the entry fusion complex (EFC), and had increased amounts of unprocessed membrane and core proteins. Total lysates of cells infected with vΔI2 also had diminished EFC proteins due to instability attributed to their hydrophobicity and failure to be inserted into viral membranes. A similar instability of EFC proteins had previously been found with unrelated mutants blocked earlier in morphogenesis that also accumulated viral membranes retaining the D13 scaffold. We concluded that I2 is required for virion morphogenesis, release of the D13 scaffold, and the association of EFC proteins with viral membranes.IMPORTANCE Poxviruses comprise a large family that infect vertebrates and invertebrates, cause disease in both in humans and in wild and domesticated animals, and are being engineered as vectors for vaccines and cancer therapy. In addition, investigations of poxviruses have provided insights into many

  14. A positive-strand RNA virus uses alternative protein-protein interactions within a viral protease/cofactor complex to switch between RNA replication and virion morphogenesis

    Science.gov (United States)

    Rey, Félix A.

    2017-01-01

    The viruses of the family Flaviviridae possess a positive-strand RNA genome and express a single polyprotein which is processed into functional proteins. Initially, the nonstructural (NS) proteins, which are not part of the virions, form complexes capable of genome replication. Later on, the NS proteins also play a critical role in virion formation. The molecular basis to understand how the same proteins form different complexes required in both processes is so far unknown. For pestiviruses, uncleaved NS2-3 is essential for virion morphogenesis while NS3 is required for RNA replication but is not functional in viral assembly. Recently, we identified two gain of function mutations, located in the C-terminal region of NS2 and in the serine protease domain of NS3 (NS3 residue 132), which allow NS2 and NS3 to substitute for uncleaved NS2-3 in particle assembly. We report here the crystal structure of pestivirus NS3-4A showing that the NS3 residue 132 maps to a surface patch interacting with the C-terminal region of NS4A (NS4A-kink region) suggesting a critical role of this contact in virion morphogenesis. We show that destabilization of this interaction, either by alanine exchanges at this NS3/4A-kink interface, led to a gain of function of the NS3/4A complex in particle formation. In contrast, RNA replication and thus replicase assembly requires a stable association between NS3 and the NS4A-kink region. Thus, we propose that two variants of NS3/4A complexes exist in pestivirus infected cells each representing a basic building block required for either RNA replication or virion morphogenesis. This could be further corroborated by trans-complementation studies with a replication-defective NS3/4A double mutant that was still functional in viral assembly. Our observations illustrate the presence of alternative overlapping surfaces providing different contacts between the same proteins, allowing the switch from RNA replication to virion formation. PMID:28151973

  15. Palmitoylation of the feline immunodeficiency virus envelope glycoprotein and its effect on fusion activity and envelope incorporation into virions

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    Gonzalez, Silvia A.; Paladino, Monica G. [Laboratorio de Virologia, CONICET-Universidad de Belgrano (UB), Villanueva 1324 (C1426BMJ), Buenos Aires (Argentina); Affranchino, Jose L., E-mail: jose.affranchino@comunidad.ub.edu.ar [Laboratorio de Virologia, CONICET-Universidad de Belgrano (UB), Villanueva 1324 (C1426BMJ), Buenos Aires (Argentina)

    2012-06-20

    The feline immunodeficiency virus (FIV) envelope glycoprotein (Env) possesses a short cytoplasmic domain of 53 amino acids containing four highly conserved cysteines at Env positions 804, 811, 815 and 848. Since palmitoylation of transmembrane proteins occurs at or near the membrane anchor, we investigated whether cysteines 804, 811 and 815 are acylated and analyzed the relevance of these residues for Env functions. Replacement of cysteines 804, 811 and 815 individually or in combination by serine residues resulted in Env glycoproteins that were efficiently expressed and processed. However, mutations C804S and C811S reduced Env fusogenicity by 93% and 84%, respectively, compared with wild-type Env. By contrast, mutant C815S exhibited a fusogenic capacity representing 50% of the wild-type value. Remarkably, the double mutation C804S/C811S abrogated both Env fusion activity and Env incorporation into virions. Finally, by means of Click chemistry assays we demonstrated that the four FIV Env cytoplasmic cysteines are palmitoylated.

  16. Incorporation of the influenza A virus NA segment into virions does not require cognate non-coding sequences

    Science.gov (United States)

    Crescenzo-Chaigne, Bernadette; Barbezange, Cyril V. S.; Léandri, Stéphane; Roquin, Camille; Berthault, Camille; van der Werf, Sylvie

    2017-01-01

    For each influenza virus genome segment, the coding sequence is flanked by non-coding (NC) regions comprising shared, conserved sequences and specific, non-conserved sequences. The latter and adjacent parts of the coding sequence are involved in genome packaging, but the precise role of the non-conserved NC sequences is still unclear. The aim of this study is to better understand the role of the non-conserved non-coding sequences in the incorporation of the viral segments into virions. The NA-segment NC sequences were systematically replaced by those of the seven other segments. Recombinant viruses harbouring two segments with identical NC sequences were successfully rescued. Virus growth kinetics and serial passages were performed, and incorporation of the viral segments was tested by real-time RT-PCR. An initial virus growth deficiency correlated to a specific defect in NA segment incorporation. Upon serial passages, growth properties were restored. Sequencing revealed that the replacing 5′NC sequence length drove the type of mutations obtained. With sequences longer than the original, point mutations in the coding region with or without substitutions in the 3′NC region were detected. With shorter sequences, insertions were observed in the 5′NC region. Restoration of viral fitness was linked to restoration of the NA segment incorporation. PMID:28240311

  17. Transcriptome analysis of rainbow trout in response to non-virion (NV) protein of viral haemorrhagic septicaemia virus (VHSV).

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    Chinchilla, Blanca; Encinas, Paloma; Estepa, Amparo; Coll, Julio M; Gomez-Casado, Eduardo

    2015-02-01

    The non-virion (NV) protein of viral haemorrhagic septicaemia virus (VHSV), an economically important fish novirhabdovirus, has been implicated in the interference of some host innate mechanisms (i.e. apoptosis) in vitro. This work aimed to characterise the immune-related transcriptome changes in rainbow trout induced by NV protein that have not yet been established in vivo. For that purpose, immune-targeted microarrays were used to analyse the transcriptomes from head kidney and spleen of rainbow trout (Oncorhynchus mykiss) after injection of recombinant NV (rNV). Results showed the extensive downregulation (and in some cases upregulation) of many innate and adaptive immune response genes not related previously to VHSV infection. The newly identified genes belonged to VHSV-induced genes (vigs), tumour necrosis factors, Toll-like receptors, antigen processing and presentation, immune co-stimulatory molecules, interleukins, macrophage chemotaxis, transcription factors, etc. Classification of differentially downregulated genes into rainbow trout immune pathways identified stat1 and jun/atf1 transcription factor genes as the most representative of the multipath gene targets of rNV. Altogether, these results contribute to define the role and effects of NV in trout by orchestrating an immunosuppression of the innate immune responses for favouring viral replication upon VHSV infection. Finally, these transcriptome results open up the possibility to find out new strategies against VHSV and better understand the interrelationships between some immune pathways in trout.

  18. Incomplete but infectious vaccinia virions are produced in the absence of oncolysis in feline SCCF1 cells.

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    Parviainen, Suvi; Autio, Karoliina; Vähä-Koskela, Markus; Guse, Kilian; Pesonen, Sari; Rosol, Thomas J; Zhao, Fang; Hemminki, Akseli

    2015-01-01

    Vaccinia virus is a large, enveloped virus of the poxvirus family. It has broad tropism and typically virus replication culminates in accumulation and lytic release of intracellular mature virus (IMV), the most abundant form of infectious virus, as well as release by budding of extracellular enveloped virus (EEV). Vaccinia viruses have been modified to replicate selectively in cancer cells and clinically tested as oncolytic agents. During preclinical screening of relevant cancer targets for a recombinant Western Reserve strain deleted for both copies of the thymidine kinase and vaccinia growth factor genes, we noticed that confluent monolayers of SCCF1 cat squamous carcinoma cells were not destroyed even after prolonged infection. Interestingly, although SCCF1 cells were not killed, they continuously secreted virus into the cell culture supernatant. To investigate this finding further, we performed detailed studies by electron microscopy. Both intracellular and secreted virions showed morphological abnormalities on ultrastructural inspection, suggesting compromised maturation and morphogenesis of vaccinia virus in SCCF1 cells. Our data suggest that SCCF1 cells produce a morphologically abnormal virus which is nevertheless infective, providing new information on the virus-host cell interactions and intracellular biology of vaccinia virus.

  19. Incomplete but infectious vaccinia virions are produced in the absence of oncolysis in feline SCCF1 cells.

    Directory of Open Access Journals (Sweden)

    Suvi Parviainen

    Full Text Available Vaccinia virus is a large, enveloped virus of the poxvirus family. It has broad tropism and typically virus replication culminates in accumulation and lytic release of intracellular mature virus (IMV, the most abundant form of infectious virus, as well as release by budding of extracellular enveloped virus (EEV. Vaccinia viruses have been modified to replicate selectively in cancer cells and clinically tested as oncolytic agents. During preclinical screening of relevant cancer targets for a recombinant Western Reserve strain deleted for both copies of the thymidine kinase and vaccinia growth factor genes, we noticed that confluent monolayers of SCCF1 cat squamous carcinoma cells were not destroyed even after prolonged infection. Interestingly, although SCCF1 cells were not killed, they continuously secreted virus into the cell culture supernatant. To investigate this finding further, we performed detailed studies by electron microscopy. Both intracellular and secreted virions showed morphological abnormalities on ultrastructural inspection, suggesting compromised maturation and morphogenesis of vaccinia virus in SCCF1 cells. Our data suggest that SCCF1 cells produce a morphologically abnormal virus which is nevertheless infective, providing new information on the virus-host cell interactions and intracellular biology of vaccinia virus.

  20. Salmonid alphavirus glycoprotein E2 requires low temperature and E1 for virion formation and induction of protective immunity.

    Science.gov (United States)

    Hikke, Mia C; Braaen, Stine; Villoing, Stephane; Hodneland, Kjartan; Geertsema, Corinne; Verhagen, Lisa; Frost, Petter; Vlak, Just M; Rimstad, Espen; Pijlman, Gorben P

    2014-10-29

    Salmonid alphavirus (SAV; also known as Salmon pancreas disease virus; family Togaviridae) causes pancreas disease and sleeping disease in Atlantic salmon and rainbow trout, respectively, and poses a major burden to the aquaculture industry. SAV infection in vivo is temperature-restricted and progeny virus is only produced at low temperatures (10-15 °C). Using engineered SAV replicons we show that viral RNA replication is not temperature-restricted suggesting that the viral structural proteins determine low-temperature dependency. The processing/trafficking of SAV glycoproteins E1 and E2 as a function of temperature was investigated via baculovirus vectors in Sf9 insect cells and by transfection of CHSE-214 fish cells with DNA constructs expressing E1 and E2. We identified SAV E2 as the temperature determinant by demonstrating that membrane trafficking and surface expression of E2 occurs only at low temperature and only in the presence of E1. Finally, a vaccination-challenge model in Atlantic salmon demonstrates the biological significance of our findings and shows that SAV replicon DNA vaccines encoding E2 elicit protective immunity only when E1 is co-expressed. This is the first study that identifies E2 as the critical determinant of SAV low-temperature dependent virion formation and defines the prerequisites for induction of a potent immune response in Atlantic salmon by DNA vaccination.

  1. Gp120 V3-dependent impairment of R5 HIV-1 infectivity due to virion-incorporated CCR5.

    Science.gov (United States)

    Monde, Kazuaki; Maeda, Yosuke; Tanaka, Yuetsu; Harada, Shinji; Yusa, Keisuke

    2007-12-21

    Entry of R5 human immunodeficiency virus type 1 (HIV-1) into target cells requires sequential interactions of the envelope glycoprotein gp120 with the receptor CD4 and the coreceptor CCR5. We investigated replication of 45 R5 viral clones derived from the HIV-1JR-FLan library carrying 0-10 random amino acid substitutions in the gp120 V3 loop. It was found that 6.7% (3/45) of the viruses revealed >or=10-fold replication suppression in PM1/CCR5 cells expressing high levels of CCR5 compared with PM1 cells expressing low levels of CCR5. In HIV-1V3L#08, suppression of replication was not associated with entry events and viral production but with a marked decrease in infectivity of nascent progeny virus. HIV-1V3L#08, generated from infected PM1/CCR5 cells, was 98% immunoprecipitated by anti-CCR5 monoclonal antibody T21/8, whereas the other infectious viruses were only partially precipitated, suggesting that incorporation of larger amounts of CCR5 into the virions caused impairment of viral infectivity in HIV-1V3L#08. The results demonstrate the implications of an alternative influence of CCR5 on HIV-1 replication.

  2. Probing the HIV-1 genomic RNA trafficking pathway and dimerization by genetic recombination and single virion analyses.

    Directory of Open Access Journals (Sweden)

    Michael D Moore

    2009-10-01

    Full Text Available Once transcribed, the nascent full-length RNA of HIV-1 must travel to the appropriate host cell sites to be translated or to find a partner RNA for copackaging to form newly generated viruses. In this report, we sought to delineate the location where HIV-1 RNA initiates dimerization and the influence of the RNA transport pathway used by the virus on downstream events essential to viral replication. Using a cell-fusion-dependent recombination assay, we demonstrate that the two RNAs destined for copackaging into the same virion select each other mostly within the cytoplasm. Moreover, by manipulating the RNA export element in the viral genome, we show that the export pathway taken is important for the ability of RNA molecules derived from two viruses to interact and be copackaged. These results further illustrate that at the point of dimerization the two main cellular export pathways are partially distinct. Lastly, by providing Gag in trans, we have demonstrated that Gag is able to package RNA from either export pathway, irrespective of the transport pathway used by the gag mRNA. These findings provide unique insights into the process of RNA export in general, and more specifically, of HIV-1 genomic RNA trafficking.

  3. Vaccinia virus protein A3 is required for the production of normal immature virions and for the encapsidation of the nucleocapsid protein L4.

    Science.gov (United States)

    Jesus, Desyree Murta; Moussatche, Nissin; McFadden, Baron B D; Nielsen, Casey Paulasue; D'Costa, Susan M; Condit, Richard C

    2015-07-01

    Maturation of the vaccinia virion is an intricate process that results in the organization of the viroplasm contained in immature virions into the lateral bodies, core wall and nucleocapsid observed in the mature particles. It is unclear how this organization takes place and studies with mutants are indispensable in understanding this process. By characterizing an inducible mutant in the A3L gene, we revealed that A3, an inner core wall protein, is important for formation of normal immature viruses and also for the correct localization of L4, a nucleocapsid protein. L4 did not accumulate in the viral factories in the absence of A3 and was not encapsidated in the particles that do not contain A3. These data strengthen our previously suggested hypothesis that A3 and L4 interact and that this interaction is critical for proper formation of the core wall and nucleocapsid.

  4. Three-dimensional visualization of the Autographa californica multiple nucleopolyhedrovirus occlusion-derived virion envelopment process gives new clues as to its mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yang; Li, Kunpeng [State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou (China); Tang, Peiping [State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou (China); Hefei National Laboratory for Physical Sciences at the Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui (China); Li, Yinyin; Zhou, Qiang; Yang, Kai [State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou (China); Zhang, Qinfen, E-mail: lsszqf@mail.sysu.edu.cn [State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou (China)

    2015-02-15

    Baculoviruses produce two virion phenotypes, occlusion-derived virion (ODV) and budded virion (BV). ODV envelopment occurs in the nucleus. Morphogenesis of the ODV has been studied extensively; however, the mechanisms underlying microvesicle formation and ODV envelopment in nuclei remain unclear. In this study, we used electron tomography (ET) together with the conventional electron microscopy to study the envelopment of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ODV. Our results demonstrate that not only the inner but also the outer nuclear membrane can invaginate and vesiculate into microvesicles and that intranuclear microvesicles are the direct source of the ODV membrane. Five main events in the ODV envelopment process are summarized, from which we propose a model to explain this process. - Highlights: • Both the inner and outer nuclear membranes could invaginate. • Both the inner and outer nuclear membranes could vesiculate into microvesicles. • Five main events in the ODV envelopment process are summarized. • A model is proposed to explain this ODV envelopment.

  5. CD4+ T cell-mediated presentation of non-infectious HIV-1virion antigens to HIV-specific CD8+ T cells

    Institute of Scientific and Technical Information of China (English)

    XU Jian-qing; Franco Lori; Julianna Lisziewicz

    2006-01-01

    Background The mechanism of chronic immune activation and impairment of HIV-specific immune responses during chronic infection is not fully understood. However, it is known that high immune activation leads to more rapid progression to AIDS. We hypothesize that CD4+ T cell-mediated viral antigen presentation contributes to this pathologic immune activation in HIV-infected individuals.Methods HIV-specific T cells, responding to noninfectious HIV-1 virions as antigen, were measured by flow cytometric assays. These experimental conditions reflect the in vivo condition where noninfectious HIV-1 represents more than 99% of the antigens.Results CD4+ T cells purified from HIV-infected individuals were capable of cross presenting exogenous noninfectious HIV-1 virions to HIV-1-specific CD8+ T cells. Cross presentation required the entry of HIV-1 to CD4+ T cells and antigen translocation from endoplasmic reticulum to the Golgi complex. Blocking CD4+mediated activation of HIV-specific CD8+ T cells and redirecting the viral antigens to antigen presenting cells improved HIV-specific T cell responses.Conclusions One possible cause of chronic immune activation and impairment of HIV-1 specific T cell responses is represented by HIV-1 harboring CD4+ T cells cross presenting HIV-1 antigen to activate CD8+ T cells. This new mechanism provides the first evidence that cross presentation of noninfectious HIV-1. Virions play a role in the immunopathogenesis of HIV-1 infection.

  6. Herpes simplex virus glycoproteins gB and gH function in fusion between the virion envelope and the outer nuclear membrane.

    Science.gov (United States)

    Farnsworth, Aaron; Wisner, Todd W; Webb, Michael; Roller, Richard; Cohen, Gary; Eisenberg, Roselyn; Johnson, David C

    2007-06-12

    Herpesviruses must traverse the nuclear envelope to gain access to the cytoplasm and, ultimately, to exit cells. It is believed that herpesvirus nucleocapsids enter the perinuclear space by budding through the inner nuclear membrane (NM). To reach the cytoplasm these enveloped particles must fuse with the outer NM and the unenveloped capsids then acquire a second envelope in the trans-Golgi network. Little is known about the process by which herpesviruses virions fuse with the outer NM. Here we show that a herpes simplex virus (HSV) mutant lacking both the two putative fusion glycoproteins gB and gH failed to cross the nuclear envelope. Enveloped virions accumulated in the perinuclear space or in membrane vesicles that bulged into the nucleoplasm (herniations). By contrast, mutants lacking just gB or gH showed only minor or no defects in nuclear egress. We concluded that either HSV gB or gH can promote fusion between the virion envelope and the outer NM. It is noteworthy that fusion associated with HSV entry requires the cooperative action of both gB and gH, suggesting that the two types of fusion (egress versus entry) are dissimilar processes.

  7. Cell-Free, De Nova Synthesis of Poliovirus

    Science.gov (United States)

    Molla, Akhteruzzaman; Paul, Aniko V.; Wimmer, Eckard

    1991-12-01

    Cell-free translation of poliovirus RNA in an extract of uninfected human (HeLa) cells yielded viral proteins through proteolysis of the polyprotein. In the extract, newly synthesized proteins catalyzed poliovirus-specific RNA synthesis, and formed infectious poliovirus de novo. Newly formed virions were neutralized by type-specific antiserum, and infection of human cells with them was prevented by poliovirus receptor-specific antibodies. Poliovirus synthesis was increased nearly 70-fold when nucleoside triphosphates were added, but it was abolished in the presence of inhibitors of translation or viral genome replication. The ability to conduct cell-free synthesis of poliovirus will aid in the study of picornavirus proliferation and in the search for the control of picornaviral disease.

  8. Potential of the virion-associated peptidoglycan hydrolase HydH5 and its derivative fusion proteins in milk biopreservation.

    Directory of Open Access Journals (Sweden)

    Lorena Rodríguez-Rubio

    Full Text Available Bacteriophage lytic enzymes have recently attracted considerable interest as novel antimicrobials against Gram-positive bacteria. In this work, antimicrobial activity in milk of HydH5 [a virion-associated peptidoglycan hydrolase (VAPGH encoded by the Staphylococcus aureus bacteriophage vB_SauS-phiIPLA88], and three different fusion proteins created between HydH5 and lysostaphin has been assessed. The lytic activity of the five proteins (HydH5, HydH5Lyso, HydH5SH3b, CHAPSH3b and lysostaphin was confirmed using commercial whole extended shelf-life milk (ESL in challenge assays with 10(4 CFU/mL of the strain S. aureus Sa9. HydH5, HydH5Lyso and HydH5SH3b (3.5 µM kept the staphylococcal viable counts below the control cultures for 6 h at 37°C. The effect is apparent just 15 minutes after the addition of the lytic enzyme. Of note, lysostaphin and CHAPSH3b showed the highest staphylolytic protection as they were able to eradicate the initial staphylococcal challenge immediately or 15 min after addition, respectively, at lower concentration (1 µM at 37°C. CHAPSH3b showed the same antistaphyloccal effect at room temperature (1.65 µM. No re-growth was observed for the remainder of the experiment (up to 6 h. CHAPSH3b activity (1.65 µM was also assayed in raw (whole and skim and pasteurized (whole and skim milk. Pasteurization of milk clearly enhanced CHAPSH3b staphylolytic activity in both whole and skim milk at both temperatures. This effect was most dramatic at room temperature as this protein was able to reduce S. aureus viable counts to undetectable levels immediately after addition with no re-growth detected for the duration of the experiment (360 min. Furthermore, CHAPSH3b protein is known to be heat tolerant and retained some lytic activity after pasteurization treatment and after storage at 4°C for 3 days. These results might facilitate the use of the peptidoglycan hydrolase HydH5 and its derivative fusions, particularly CHAPSH3b, as

  9. Role of herpes simplex virus ICP27 in the degradation of mRNA by virion host shutoff RNase.

    Science.gov (United States)

    Taddeo, Brunella; Zhang, Weiran; Roizman, Bernard

    2010-10-01

    The virion host shutoff (VHS) RNase tegument protein released into cells by infecting virus has two effects. Preexisting stable mRNAs (e.g., GAPDH [glyceraldehyde-3-phosphate dehydrogenase]) are rapidly degraded. Stress response RNAs containing AU-rich elements (AREs) in the 3' untranslated region (3'UTR) are deadenylated and cleaved, but the cleavage products persist for hours, in contrast to the short half-lives of ARE-containing mRNAs in uninfected cells. At late times, the VHS RNase is neutralized by the viral structural proteins VP16 and VP22. A recent study (J. A. Corcoran, W. L. Hsu, and J. R. Smiley, J. Virol. 80:9720-9729, 2006) reported that, at relatively late times after infection, ARE RNAs are rapidly degraded in cells infected with DeltaICP27 mutant virus and concluded that ICP27 "stabilizes" ARE mRNAs. We report the following. (i) The rates of degradation of ARE mRNA at early times (3 h) after infection with the wild type or the DeltaICP27 mutant virus are virtually identical, and hence ICP27 plays no role in this process. (ii) In noncomplementing cells, VHS RNase or VP22 is not synthesized. Therefore, the only VHS that is active is brought into cells by the DeltaICP27 mutant. (ii) The VHS RNase brought into the cells by the DeltaICP27 virus is reduced in potency relative to that of wild-type virus. Hence the rapid degradation of ARE mRNAs noted in DeltaICP27 mutant-infected cells at late times is similar to that taking place in mock-infected or in DeltaVHS RNase mutant-virus-infected cells and does not by itself support the hypothesis that ICP27 stabilizes ARE mRNAs. (iii) Concurrently, we present the first evidence that VHS RNase interacts with ICP27 most likely when bound to cap- and poly(A)-binding proteins, respectively.

  10. Disassembly and reassembly of human papillomavirus virus-like particles produces more virion-like antibody reactivity

    Directory of Open Access Journals (Sweden)

    Zhao Qinjian

    2012-02-01

    Full Text Available Abstract Background Human papillomavirus (HPV vaccines based on major capsid protein L1 are licensed in over 100 countries to prevent HPV infections. The yeast-derived recombinant quadrivalent HPV L1 vaccine, GARDASIL(R, has played an important role in reducing cancer and genital warts since its introduction in 2006. The L1 proteins self-assemble into virus-like particles (VLPs. Results VLPs were subjected to post-purification disassembly and reassembly (D/R treatment during bioprocessing to improve VLP immunoreactivity and stability. The post-D/R HPV16 VLPs and their complex with H16.V5 neutralizing antibody Fab fragments were visualized by cryo electron microscopy, showing VLPs densely decorated with antibody. Along with structural improvements, post-D/R VLPs showed markedly higher antigenicity to conformational and neutralizing monoclonal antibodies (mAbs H16.V5, H16.E70 and H263.A2, whereas binding to mAbs recognizing linear epitopes (H16.J4, H16.O7, and H16.H5 was greatly reduced. Strikingly, post-D/R VLPs showed no detectable binding to H16.H5, indicating that the H16.H5 epitope is not accessible in fully assembled VLPs. An atomic homology model of the entire HPV16 VLP was generated based on previously determined high-resolution structures of bovine papillomavirus and HPV16 L1 pentameric capsomeres. Conclusions D/R treatment of HPV16 L1 VLPs produces more homogeneous VLPs with more virion-like antibody reactivity. These effects can be attributed to a combination of more complete and regular assembly of the VLPs, better folding of L1, reduced non-specific disulfide-mediated aggregation and increased stability of the VLPs. Markedly different antigenicity of HPV16 VLPs was observed upon D/R treatment with a panel of monoclonal antibodies targeting neutralization sensitive epitopes. Multiple epitope-specific assays with a panel of mAbs with different properties and epitopes are required to gain a better understanding of the immunochemical

  11. Mapping in vitro local material properties of intact and disrupted virions at high resolution using multi-harmonic atomic force microscopy

    Science.gov (United States)

    Cartagena, Alexander; Hernando-Pérez, Mercedes; Carrascosa, José L.; de Pablo, Pedro J.; Raman, Arvind

    2013-05-01

    Understanding the relationships between viral material properties (stiffness, strength, charge density, adhesion, hydration, viscosity, etc.), structure (protein sub-units, genome, surface receptors, appendages), and functions (self-assembly, stability, disassembly, infection) is of significant importance in physical virology and nanomedicine. Conventional Atomic Force Microscopy (AFM) methods have measured a single physical property such as the stiffness of the entire virus from nano-indentation at a few points which severely limits the study of structure-property-function relationships. We present an in vitro dynamic AFM technique operating in the intermittent contact regime which synthesizes anharmonic Lorentz-force excited AFM cantilevers to map quantitatively at nanometer resolution the local electro-mechanical force gradient, adhesion, and hydration layer viscosity within individual φ29 virions. Furthermore, the changes in material properties over the entire φ29 virion provoked by the local disruption of its shell are studied, providing evidence of bacteriophage depressurization. The technique significantly generalizes recent multi-harmonic theory (A. Raman, et al., Nat. Nanotechnol., 2011, 6, 809-814) and enables high-resolution in vitro quantitative mapping of multiple material properties within weakly bonded viruses and nanoparticles with complex structure that otherwise cannot be observed using standard AFM techniques.Understanding the relationships between viral material properties (stiffness, strength, charge density, adhesion, hydration, viscosity, etc.), structure (protein sub-units, genome, surface receptors, appendages), and functions (self-assembly, stability, disassembly, infection) is of significant importance in physical virology and nanomedicine. Conventional Atomic Force Microscopy (AFM) methods have measured a single physical property such as the stiffness of the entire virus from nano-indentation at a few points which severely limits the

  12. Corneal replication is an interferon response-independent bottleneck for virulence of herpes simplex virus 1 in the absence of virion host shutoff.

    Science.gov (United States)

    Pasieka, Tracy Jo; Menachery, Vineet D; Rosato, Pamela C; Leib, David A

    2012-07-01

    Herpes simplex viruses lacking the virion host shutoff function (Δvhs) are avirulent and hypersensitive to type I and type II interferon (IFN). In this study, we demonstrate that even in the absence of IFN responses in AG129 (IFN-αβγR(-/-)) mice, Δvhs remains highly attenuated via corneal infection but is fully virulent via intracranial infection. The data demonstrate that the interferon-independent inherent replication defect of Δvhs has a significant impact upon peripheral replication and neuroinvasion.

  13. Demonstration of non-infectious hemagglutinating particles of rabies virus and isolation of the hemagglutinin by disruption of the virion with Nonidet P-40.

    Science.gov (United States)

    Arai, Y T; Kondo, A; Suzuki, K

    1976-01-01

    Non-infectious hemagglutinating particles of rabies virus accumulated in the fluid phase of chick embryo cell cultures at 6 days post-infection, though they were undetectable at 4 days. They were characterized as looped filaments resembling viral envelope as revealed by electron microscopy. Another form of hemagglutinin (HAnin) was obtained by solubilization of partially purified virions with Nonidet P-40 (NP-40) followed by successive high speed and CsCl density gradient centrifugations. The density of the isolated HAnin averaged 1.28 g/cm3. SDS-polyacrylamide gel electrophoresis of the HAnin demonstrated that it was mainly composed of a glycoprotein (G) with a molecular weight of 83,000. Electron microscopically, it differed from the above non-infectious hemagglutinating particles, being much smaller in size and showing a star- or rosette-like appearance with a diameter of about 25 nm, composed of a central particle surrounded by particles resembling envelope-spikes. Virus-neutralizing (VN) and hemagglutination inhibiting (HI) antibodies were produced in rabbits immunized with the HAnin isolated from virions.

  14. A Leucine Residue in the C Terminus of Human Parainfluenza Virus Type 3 Matrix Protein Is Essential for Efficient Virus-Like Particle and Virion Release

    Science.gov (United States)

    Zhang, Guangyuan; Zhang, Shengwei; Ding, Binbin; Yang, Xiaodan; Chen, Longyun; Yan, Qin; Jiang, Yanliang; Zhong, Yi

    2014-01-01

    ABSTRACT Paramyxovirus particles, like other enveloped virus particles, are formed by budding from membranes of infected cells, and matrix (M) proteins are critical for this process. To identify the M protein important for this process, we have characterized the budding of the human parainfluenza virus type 3 (HPIV3) M protein. Our results showed that expression of the HPIV3 M protein alone is sufficient to initiate the release of virus-like particles (VLPs). Electron microscopy analysis confirmed that VLPs are morphologically similar to HPIV3 virions. We identified a leucine (L302) residue within the C terminus of the HPIV3 M protein that is critical for M protein-mediated VLP production by regulating the ubiquitination of the M protein. When L302 was mutated into A302, ubiquitination of M protein was defective, the release of VLPs was abolished, and the membrane binding and budding abilities of M protein were greatly weakened, but the ML302A mutant retained oligomerization activity and had a dominant negative effect on M protein-mediated VLP production. Furthermore, treatment with a proteasome inhibitor also inhibited M protein-mediated VLP production and viral budding. Finally, recombinant HPIV3 containing the ML302A mutant could not be rescued. These results suggest that L302 acts as a critical regulating signal for the ubiquitination of the HPIV3 M protein and virion release. IMPORTANCE Human parainfluenza virus type 3 (HPIV3) is an enveloped virus with a nonsegmented negative-strand RNA genome. It can cause severe respiratory tract diseases, such as bronchiolitis, pneumonia, and croup in infants and young children. However, no valid antiviral therapy or vaccine is currently available. Thus, further elucidation of its assembly and budding will be helpful in the development of novel therapeutic approaches. Here, we show that a leucine residue (L302) located at the C terminus of the HPIV3 M protein is essential for efficient production of virus-like particles

  15. Hepatitis B virus genotype C isolates with wild-type core promoter sequence replicate less efficiently than genotype B isolates but possess higher virion secretion capacity.

    Science.gov (United States)

    Qin, Yanli; Tang, Xiaoli; Garcia, Tamako; Hussain, Munira; Zhang, Jiming; Lok, Anna; Wands, Jack; Li, Jisu; Tong, Shuping

    2011-10-01

    Infection by hepatitis B virus (HBV) genotype C is associated with a prolonged viremic phase, delayed hepatitis B e antigen (HBeAg) seroconversion, and an increased incidence of liver cirrhosis and hepatocellular carcinoma compared with genotype B infection. Genotype C is also associated with the more frequent emergence of core promoter mutations, which increase genome replication and are independently associated with poor clinical outcomes. We amplified full-length HBV genomes from serum samples from Chinese and U. S. patients with chronic HBV infection and transfected circularized genome pools or dimeric constructs of individual clones into Huh7 cells. The two genotypes could be differentiated by Western blot analysis due to the reactivities of M and L proteins toward a monoclonal pre-S2 antibody and slightly different S-protein mobilities. Great variability in replication capacity was observed for both genotypes. The A1762T/G1764A core promoter mutations were prevalent in genotype C isolates and correlated with increased replication capacity, while the A1752G/T mutation frequently found in genotype B isolates correlated with a low replication capacity. Importantly, most genotype C isolates with wild-type core promoter sequence replicated less efficiently than the corresponding genotype B isolates due to less efficient transcription of the 3.5-kb RNA. However, genotype C isolates often displayed more efficient virion secretion. We propose that the low intracellular levels of viral DNA and core protein of wild-type genotype C delay immune clearance and trigger the subsequent emergence of A1762T/G1764A core promoter mutations to upregulate replication; efficient virion secretion compensates for the low replication capacity to ensure the establishment of persistent infection by genotype C.

  16. Binding of herpes simplex virus type-1 virions leads to the induction of intracellular signalling in the absence of virus entry.

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    Iain J MacLeod

    Full Text Available The envelope of HSV-1 contains a number of glycoproteins, four of which are essential for virus entry. Virus particles lacking gB, gD, gH or gL are entry-defective, although these viruses retain the ability to bind to the plasma membrane via the remaining glycoproteins. Soluble forms of gD have been shown to trigger the nuclear translocation of the NF-kappaB transcriptional complex in addition to stimulating the production of Type I interferon. By taking advantage of the entry-defective phenotype of glycoprotein-deficient HSV-1 virus particles, the results presented here show that binding of virions to cellular receptors on the plasma membrane is sufficient to stimulate a change in cellular gene expression. Preliminary microarray studies, validated by quantitative real-time PCR, identified the differential expression of cellular genes associated with the NF-kappaB, PI3K/Akt, Jak/Stat and related Jak/Src pathways by virions lacking gB or gH but not gD. Gene induction occurred at a few particles per cell, corresponding to physiological conditions during primary infection. Reporter assay studies determined that NF-kappaB transcriptional activity is stimulated within an hour of HSV-1 binding, peaks between two and three hours post-binding and declines to background levels by five hours after induction. The immediate, transient nature of these signalling events suggests that HSV-1 glycoproteins, particularly gD, may alter the cellular environment pre-entry so as to condition the cell for viral replication.

  17. Effect of the deletion of genes encoding proteins of the extracellular virion form of vaccinia virus on vaccine immunogenicity and protective effectiveness in the mouse model.

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    Clement A Meseda

    Full Text Available Antibodies to both infectious forms of vaccinia virus, the mature virion (MV and the enveloped virion (EV, as well as cell-mediated immune response appear to be important for protection against smallpox. EV virus particles, although more labile and less numerous than MV, are important for dissemination and spread of virus in infected hosts and thus important in virus pathogenesis. The importance of the EV A33 and B5 proteins for vaccine induced immunity and protection in a murine intranasal challenge model was evaluated by deletion of both the A33R and B5R genes in a vaccine-derived strain of vaccinia virus. Deletion of either A33R or B5R resulted in viruses with a small plaque phenotype and reduced virus yields, as reported previously, whereas deletion of both EV protein-encoding genes resulted in a virus that formed small infection foci that were detectable and quantifiable only by immunostaining and an even more dramatic decrease in total virus yield in cell culture. Deletion of B5R, either as a single gene knockout or in the double EV gene knockout virus, resulted in a loss of EV neutralizing activity, but all EV gene knockout viruses still induced a robust neutralizing activity against the vaccinia MV form of the virus. The effect of elimination of A33 and/or B5 on the protection afforded by vaccination was evaluated by intranasal challenge with a lethal dose of either vaccinia virus WR or IHD-J, a strain of vaccinia virus that produces relatively higher amounts of EV virus. The results from multiple experiments, using a range of vaccination doses and virus challenge doses, and using mortality, morbidity, and virus dissemination as endpoints, indicate that the absence of A33 and B5 have little effect on the ability of a vaccinia vaccine virus to provide protection against a lethal intranasal challenge in a mouse model.

  18. A new virion precipitation test for oncovirus envelope antigens which detects common antigenic determinants in mammalian type-C viruses and Mason-Pfizer monkey virus.

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    Altstein, A D; Zakharova, L G; Zhdanov, V M

    1979-03-15

    A method for the study of oncovirus envelope antigens was developed, bases on the precipitation of intact virions by a double antibody technique. The amount of precipitated virus was then measured as reverse transcriptase activity. The method was designated the virion precipitation test (VPT). It has been used for titration of antibodies to envelope antigens of oncoviruses. The study of envelop antigens of 11 different oncoviruses permitted their differentiation into the following groups: (1) murine type-C viruses: (2) feline type-C viruses; (3) simian type-C viruses; (4) the RD-114/BEV group; (5) Mason-Pfizer monkey virus (M-PMV); (6) bovine leukemia virus; (7) avian type-C viruses; (8) mouse mammary tumor virus. No common antigenic determinants were detected in the last three groups. Mammalian type-C viruses (RD-114, NIH-MuLV, G-MuLV) had common antigenic determinants in the envelope, as demonstrated with an anti-RD-114 serum. Mammalian type-C viruses also shared antigenic determinants with M-PMV. The relationship of type-C viruses to M-PMV decreased in the following order: RD-114--NIH-MuLV--G-MuLV. It was also shown that the endogenous xenotropic feline RD-114 virus was more closely related to xenotropic NIH-MuLV than to ecotropic G-MuLV. The nature of the common antigenic determinants, as demonstrated by VPT on the surface of mammalian type-C viruses and M-PMV, and their significance for the concept of oncovirus evolution are discussed.

  19. Multi-faceted proteomic characterization of host protein complement of Rift Valley fever virus virions and identification of specific heat shock proteins, including HSP90, as important viral host factors.

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    Nuss, Jonathan E; Kehn-Hall, Kylene; Benedict, Ashwini; Costantino, Julie; Ward, Michael; Peyser, Brian D; Retterer, Cary J; Tressler, Lyal E; Wanner, Laura M; McGovern, Hugh F; Zaidi, Anum; Anthony, Scott M; Kota, Krishna P; Bavari, Sina; Hakami, Ramin M

    2014-01-01

    Rift Valley fever is a potentially fatal disease of humans and domestic animals caused by Rift Valley fever virus (RVFV). Infection with RVFV in ruminants can cause near 100% abortion rates and recent outbreaks in naïve human populations have suggested case fatality rates of greater than thirty percent. To elucidate the roles that host proteins play during RVFV infection, proteomic analysis of RVFV virions was conducted using complementary analytical approaches, followed by functional validation studies of select identified host factors. Coupling the more traditional Gel LC/MS/MS approach (SDS PAGE followed by liquid chromatography tandem mass spectrometry) with an alternative technique that preserves protein complexes allowed the protein complement of these viral particles to be thoroughly examined. In addition to viral proteins present within the virions and virion-associated host proteins, multiple macromolecular complexes were identified. Bioinformatic analysis showed that host chaperones were among over-represented protein families associated with virions, and functional experiments using siRNA gene silencing and small molecule inhibitors identified several of these heat shock proteins, including heat shock protein 90 (HSP90), as important viral host factors. Further analysis indicated that HSP inhibition effects occur during the replication/transcription phase of the virus life cycle, leading to significant lowering of viral titers without compromising the functional capacity of released virions. Overall, these studies provide much needed further insight into interactions between RVFV and host cells, increasing our understanding of the infection process and suggesting novel strategies for anti-viral development. In particular, considering that several HSP90 inhibitors have been advancing through clinical trials for cancer treatment, these results also highlight the exciting potential of repurposing HSP90 inhibitors to treat RVF.

  20. Multi-faceted proteomic characterization of host protein complement of Rift Valley fever virus virions and identification of specific heat shock proteins, including HSP90, as important viral host factors.

    Directory of Open Access Journals (Sweden)

    Jonathan E Nuss

    Full Text Available Rift Valley fever is a potentially fatal disease of humans and domestic animals caused by Rift Valley fever virus (RVFV. Infection with RVFV in ruminants can cause near 100% abortion rates and recent outbreaks in naïve human populations have suggested case fatality rates of greater than thirty percent. To elucidate the roles that host proteins play during RVFV infection, proteomic analysis of RVFV virions was conducted using complementary analytical approaches, followed by functional validation studies of select identified host factors. Coupling the more traditional Gel LC/MS/MS approach (SDS PAGE followed by liquid chromatography tandem mass spectrometry with an alternative technique that preserves protein complexes allowed the protein complement of these viral particles to be thoroughly examined. In addition to viral proteins present within the virions and virion-associated host proteins, multiple macromolecular complexes were identified. Bioinformatic analysis showed that host chaperones were among over-represented protein families associated with virions, and functional experiments using siRNA gene silencing and small molecule inhibitors identified several of these heat shock proteins, including heat shock protein 90 (HSP90, as important viral host factors. Further analysis indicated that HSP inhibition effects occur during the replication/transcription phase of the virus life cycle, leading to significant lowering of viral titers without compromising the functional capacity of released virions. Overall, these studies provide much needed further insight into interactions between RVFV and host cells, increasing our understanding of the infection process and suggesting novel strategies for anti-viral development. In particular, considering that several HSP90 inhibitors have been advancing through clinical trials for cancer treatment, these results also highlight the exciting potential of repurposing HSP90 inhibitors to treat RVF.

  1. Role of the virion host shutoff protein in neurovirulence of monkey B virus(Macacine herpesvirus 1)

    Institute of Scientific and Technical Information of China (English)

    Darla; Black; Jerry; Ritchey; Mark; Payton; Richard; Eberle

    2014-01-01

    Monkey B virus(Macacine herpesvirus 1; BV) is noted for its extreme neurovirulence in humans. Since the vhs protein encoded by the UL41 gene has been shown to be a neurovirulence factor in the related human herpes simplex viruses, the role of the UL41 gene in BV neurovirulence was investigated. BV mutants were constructed that lacked the entire UL41 ORF(Δ41) or had the RNase active site mutated(Δ41A). Neither mutant shut off host protein synthesis, degraded β-actin mRNA, or prevented an IFN-β response, indicating that the vhs protein and its RNase activity are both necessary for these activities. Replication of both mutants in primary mouse cells was impaired and they exhibited a prolonged disease course in mice. Whereas Δ41 infected mice were euthanized for symptoms related to central nervous system(CNS) infection, Δ41A infected mice were euthanized primarily for symptoms of autonomic nervous system dysfunction. While neuroinvasiveness was not affected, lesions in the CNS were more limited in size, anatomical distribution, and severity than for wild-type virus. These results indicate that the vhs protein affects the general replicative efficiency of BV in vivo rather than being a specific neurovirulence factor critical for invasion of or preferential replication in the CNS.

  2. Lytic activity of the virion-associated peptidoglycan hydrolase HydH5 of Staphylococcus aureus bacteriophage vB_SauS-phiIPLA88

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    Donovan David M

    2011-06-01

    Full Text Available Abstract Background Staphylococcus aureus is a food-borne pathogen and the most common cause of infections in hospitalized patients. The increase in the resistance of this pathogen to antibacterials has made necessary the development of new anti-staphylococcal agents. In this context, bacteriophage lytic enzymes such as endolysins and structural peptidoglycan (PG hydrolases have received considerable attention as possible antimicrobials against gram-positive bacteria. Results S. aureus bacteriophage vB_SauS-phiIPLA88 (phiIPLA88 contains a virion-associated muralytic enzyme (HydH5 encoded by orf58, which is located in the morphogenetic module. Comparative bioinformatic analysis revealed that HydH5 significantly resembled other peptidoglycan hydrolases encoded by staphylococcal phages. The protein consists of 634 amino acid residues. Two putative lytic domains were identified: an N-terminal CHAP (cysteine, histidine-dependent amidohydrolase/peptidase domain (135 amino acid residues, and a C-terminal LYZ2 (lysozyme subfamily 2 domain (147 amino acid residues. These domains were also found when a predicted three-dimensional structure of HydH5 was made which provided the basis for deletion analysis. The complete HydH5 protein and truncated proteins containing only each catalytic domain were overproduced in E. coli and purified from inclusion bodies by subsequent refolding. Truncated and full-length HydH5 proteins were all able to bind and lyse S. aureus Sa9 cells as shown by binding assays, zymogram analyses and CFU reduction analysis. HydH5 demonstrated high antibiotic activity against early exponential cells, at 45°C and in the absence of divalent cations (Ca2+, Mg2+, Mn2+. Thermostability assays showed that HydH5 retained 72% of its activity after 5 min at 100°C. Conclusions The virion-associated PG hydrolase HydH5 has lytic activity against S. aureus, which makes it attractive as antimicrobial for food biopreservation and anti

  3. The virion host shut-off (vhs protein blocks a TLR-independent pathway of herpes simplex virus type 1 recognition in human and mouse dendritic cells.

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    Christopher R Cotter

    Full Text Available Molecular pathways underlying the activation of dendritic cells (DCs in response to Herpes Simplex Virus type 1 (HSV-1 are poorly understood. Removal of the HSV virion host shut-off (vhs protein relieves a block to DC activation observed during wild-type infection. In this study, we utilized a potent DC stimulatory HSV-1 recombinant virus lacking vhs as a tool to investigate the mechanisms involved in the activation of DCs by HSV-1. We report that the release of pro-inflammatory cytokines by conventional DC (cDC during HSV-1 infection is triggered by both virus replication-dependent and replication-independent pathways. Interestingly, while vhs is capable of inhibiting the release of cytokines during infection of human and mouse cDCs, the secretion of cytokines by plasmacytoid DC (pDC is not affected by vhs. These data prompted us to postulate that infection of cDCs by HSV triggers a TLR independent pathway for cDC activation that is susceptible to blockage by the vhs protein. Using cDCs isolated from mice deficient in both the TLR adaptor protein MyD88 and TLR3, we show that HSV-1 and the vhs-deleted virus can activate cDCs independently of TLR signaling. In addition, virion-associated vhs fails to block cDC activation in response to treatment with TLR agonists, but it efficiently blocked cDC activation triggered by the paramyxoviruses Sendai Virus (SeV and Newcastle Disease Virus (NDV. This block to SeV- and NDV-induced activation of cDC resulted in elevated SeV and NDV viral gene expression indicating that infection with HSV-1 enhances the cell's susceptibility to other pathogens through the action of vhs. Our results demonstrate for the first time that a viral protein contained in the tegument of HSV-1 can block the induction of DC activation by TLR-independent pathways of viral recognition.

  4. Herpes simplex virus 1 induces de novo phospholipid synthesis

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    Sutter, Esther [Electron Microscopy, Institute of Veterinary Anatomy, University of Zuerich (Switzerland); Oliveira, Anna Paula de; Tobler, Kurt [Electron microscopy, Institute of Virology, University of Zuerich (Switzerland); Schraner, Elisabeth M. [Electron Microscopy, Institute of Veterinary Anatomy, University of Zuerich (Switzerland); Sonda, Sabrina [Institute of Parasitology, University of Zuerich (Switzerland); Kaech, Andres [Center for Microscopy and Image Analysis, University of Zuerich (Switzerland); Lucas, Miriam S. [Electron Microscopy ETH Zuerich (EMEZ), Swiss Federal Institute of Technology, Zuerich (Switzerland); Ackermann, Mathias [Electron microscopy, Institute of Virology, University of Zuerich (Switzerland); Wild, Peter, E-mail: pewild@access.uzh.ch [Electron Microscopy, Institute of Veterinary Anatomy, University of Zuerich (Switzerland)

    2012-08-01

    Herpes simplex virus type 1 capsids bud at nuclear membranes and Golgi membranes acquiring an envelope composed of phospholipids. Hence, we measured incorporation of phospholipid precursors into these membranes, and quantified changes in size of cellular compartments by morphometric analysis. Incorporation of [{sup 3}H]-choline into both nuclear and cytoplasmic membranes was significantly enhanced upon infection. [{sup 3}H]-choline was also part of isolated virions even grown in the presence of brefeldin A. Nuclei expanded early in infection. The Golgi complex and vacuoles increased substantially whereas the endoplasmic reticulum enlarged only temporarily. The data suggest that HSV-1 stimulates phospholipid synthesis, and that de novo synthesized phospholipids are inserted into nuclear and cytoplasmic membranes to i) maintain membrane integrity in the course of nuclear and cellular expansion, ii) to supply membrane constituents for envelopment of capsids by budding at nuclear membranes and Golgi membranes, and iii) to provide membranes for formation of transport vacuoles.

  5. Elimination of contaminating cap genes in AAV vector virions reduces immune responses and improves transgene expression in a canine gene therapy model.

    Science.gov (United States)

    Wang, Z; Halbert, C L; Lee, D; Butts, T; Tapscott, S J; Storb, R; Miller, A D

    2014-04-01

    Animal and human gene therapy studies utilizing AAV vectors have shown that immune responses to AAV capsid proteins can severely limit transgene expression. The main source of capsid antigen is that associated with the AAV vectors, which can be reduced by stringent vector purification. A second source of AAV capsid proteins is that expressed from cap genes aberrantly packaged into AAV virions during vector production. This antigen source can be eliminated by the use of a cap gene that is too large to be incorporated into an AAV capsid, such as a cap gene containing a large intron (captron gene). Here, we investigated the effects of elimination of cap gene transfer and of vector purification by CsCl gradient centrifugation on AAV vector immunogenicity and expression following intramuscular injection in dogs. We found that both approaches reduced vector immunogenicity and that combining the two produced the lowest immune responses and highest transgene expression. This combined approach enabled the use of a relatively mild immunosuppressive regimen to promote robust micro-dystrophin gene expression in Duchenne muscular dystrophy-affected dogs. Our study shows the importance of minimizing AAV cap gene impurities and indicates that this improvement in AAV vector production may benefit human applications.

  6. Cleavage of the HPV16 Minor Capsid Protein L2 during Virion Morphogenesis Ablates the Requirement for Cellular Furin during De Novo Infection

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    Linda Cruz

    2015-11-01

    Full Text Available Infections by high-risk human papillomaviruses (HPV are the causative agents for the development of cervical cancer. As with other non-enveloped viruses, HPVs are taken up by the cell through endocytosis following primary attachment to the host cell. Through studies using recombinant pseudovirus particles (PsV, many host cellular proteins have been implicated in the process. The proprotein convertase furin has been demonstrated to cleave the minor capsid protein, L2, post-attachment to host cells and is required for infectious entry by HPV16 PsV. In contrast, using biochemical inhibition by a furin inhibitor and furin-negative cells, we show that tissue-derived HPV16 native virus (NV initiates infection independent of cellular furin. We show that HPV16 L2 is cleaved during virion morphogenesis in differentiated tissue. In addition, HPV45 is also not dependent on cellular furin, but two other alpha papillomaviruses, HPV18 and HPV31, are dependent on the activity of cellular furin for infection.

  7. Enhanced expression of HIV and SIV vaccine antigens in the structural gene region of live attenuated rubella viral vectors and their incorporation into virions.

    Science.gov (United States)

    Virnik, Konstantin; Ni, Yisheng; Berkower, Ira

    2013-04-19

    Despite the urgent need for an HIV vaccine, its development has been hindered by virus variability, weak immunogenicity of conserved epitopes, and limited durability of the immune response. For other viruses, difficulties with immunogenicity were overcome by developing live attenuated vaccine strains. However, there is no reliable method of attenuation for HIV, and an attenuated strain would risk reversion to wild type. We have developed rubella viral vectors, based on the live attenuated vaccine strain RA27/3, which are capable of expressing important HIV and SIV vaccine antigens. The rubella vaccine strain has demonstrated safety, immunogenicity, and long lasting protection in millions of children. Rubella vectors combine the growth and immunogenicity of live rubella vaccine with the antigenicity of HIV or SIV inserts. This is the first report showing that live attenuated rubella vectors can stably express HIV and SIV vaccine antigens at an insertion site located within the structural gene region. Unlike the Not I site described previously, the new site accommodates a broader range of vaccine antigens without interfering with essential viral functions. In addition, antigens expressed at the structural site were controlled by the strong subgenomic promoter, resulting in higher levels and longer duration of antigen expression. The inserts were expressed as part of the structural polyprotein, processed to free antigen, and incorporated into rubella virions. The rubella vaccine strain readily infects rhesus macaques, and these animals will be the model of choice for testing vector growth in vivo and immunogenicity.

  8. A conserved genetic module that encodes the major virion components in both the coliphage T4 and the marine cyanophage S-PM2.

    Science.gov (United States)

    Hambly, E; Tétart, F; Desplats, C; Wilson, W H; Krisch, H M; Mann, N H

    2001-09-25

    Sequence analysis of a 10-kb region of the genome of the marine cyanomyovirus S-PM2 reveals a homology to coliphage T4 that extends as a contiguous block from gene (g)18 to g23. The order of the S-PM2 genes in this region is similar to that of T4, but there are insertions and deletions of small ORFs of unknown function. In T4, g18 codes for the tail sheath, g19, the tail tube, g20, the head portal protein, g21, the prohead core protein, g22, a scaffolding protein, and g23, the major capsid protein. Thus, the entire module that determines the structural components of the phage head and contractile tail is conserved between T4 and this cyanophage. The significant differences in the morphology of these phages must reflect the considerable divergence of the amino acid sequence of their homologous virion proteins, which uniformly exceeds 50%. We suggest that their enormous diversity in the sea could be a result of genetic shuffling between disparate phages mediated by such commonly shared modules. These conserved sequences could facilitate genetic exchange by providing partially homologous substrates for recombination between otherwise divergent phage genomes. Such a mechanism would thus expand the pool of phage genes accessible by recombination to all those phages that share common modules.

  9. Herpes simplex virus type 2 virion host shutoff protein suppresses innate dsRNA antiviral pathways in human vaginal epithelial cells.

    Science.gov (United States)

    Yao, Xiao-Dan; Rosenthal, Kenneth Lee

    2011-09-01

    Viruses that establish persistent infections have evolved numerous strategies to evade host innate antiviral responses. We functionally assessed the role of herpes simplex virus type 2 (HSV-2) virion host shutoff (vhs) protein on innate immune sensing pathways in human vaginal epithelial cells (VK2 ECs). Infection of cells with wild-type (WT) HSV-2 significantly decreased expression of innate immune sensors of viral infection, Toll-like receptor (TLR)2, TLR3, retinoic acid inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (Mda-5), relative to cells infected with a mutant that lacks vhs (vhsB) or mock-infected cells. Transfection with HSV-2 vhs similarly decreased expression of TLR2, TLR3, RIG-I and Mda-5, which was also confirmed in human embryonic kidney (HEK) 293 cells. vhsB infection of VK2 cells caused robust increases in the active form of interferon regulatory factor (IRF)3 and its translocation to the nucleus compared with the WT. Additionally, IRF3 activation by Sendai virus and polyinosinic : polycytidylic acid-induced stimulation of beta interferon (IFN-β) was significantly inhibited in vhs-transfected cells. Overall, our findings provide the first evidence that HSV-2 vhs plays roles in selectively inhibiting TLR3 and RIG-I/Mda-5, as well as TLR2-mediated antiviral pathways for sensing dsRNA and effectively suppresses IFN-β antiviral responses in human vaginal ECs.

  10. The virion host shutoff RNase plays a key role in blocking the activation of protein kinase R in cells infected with herpes simplex virus 1.

    Science.gov (United States)

    Sciortino, Maria Teresa; Parisi, Tiziana; Siracusano, Gabriel; Mastino, Antonio; Taddeo, Brunella; Roizman, Bernard

    2013-03-01

    Earlier studies have shown that active MEK blocks the activation of protein kinase R (PKR), a component of antiviral innate immune responses. In this report we show that the herpes simplex virus 1 virion host shutoff (VHS) RNase protein and MEK (mitogen-activated protein kinase kinase) act cooperatively in blocking the activation of PKR. This conclusion is based on the following. (i) In contrast to viral gene expression in the parental cell line or a cell line expressing a constitutively active MEK, the replication of a VHS mutant is particularly impaired in cells expressing dominant negative MEK. In this cell line PKR is activated by phosphorylation, and the accumulation of several viral proteins is delayed. (ii) In transfected cells, wild-type VHS blocked the activation of PKR, whereas PKR was activated in cells transfected with a mutant VHS or with plasmids encoding the VHS RNase and VP16 and VP22, the two viral proteins that neutralize the RNase activity of VHS. The results suggest that early in infection the VHS RNase degrades RNAs that activate PKR. Coupled with published data, the results suggest that inhibition of activation of PKR or its effect on viral replication is staged early in infection by VHS, postsynthesis of VP16 and VP22 by the γ(1)34.5 protein, and very late in infection by the U(S)11 protein.

  11. Antiviral effects of single-stranded polynucleotide inhibitors of the influenza virion-associated transcriptase against influenza virus infection of hamsters and ferrets.

    Science.gov (United States)

    Round, E M; Stebbing, N

    1981-11-01

    Administration of a single-stranded polynucleotide copolymer containing 9% cytidine residues and 91% 4-thiouridine residues [poly(C,S4U10)], a known potent inhibitor of the virion transcriptase of influenza viruses, suppressed the amount of virus recoverable from the nasal washes of influenza virus-infected hamsters and ferrets. The incidence of sneezing and nasal discharge in infected ferrets was also reduced. In hamsters, poly(C,S4U10) was more effective than amantadine-HCl or Virazole. Polyinosinic acid in combination with poly-5-hydroxy cytidylic acid also had anti-influenza effects. Poly(C,S4U10) annealed to polyadenylic acid was not effective, nor was the double-stranded polymer (polyinosinic acid) . (polycytidylic acid) even when complexed with carboxymethylcellulose and polylysine. No toxic effects of poly(C,S4U10) were apparent in the treated hamsters and ferrets, and high doses (greater than or equal to 2.86 g/kg) administered intraperitoneally to mice produced no adverse effects.

  12. HIV-1 Infection of T Cells and Macrophages Are Differentially Modulated by Virion-Associated Hck: A Nef-Dependent Phenomenon

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    Gilda Tachedjian

    2013-09-01

    Full Text Available The proline repeat motif (PxxP of Nef is required for interaction with the SH3 domains of macrophage-specific Src kinase Hck. However, the implication of this interaction for viral replication and infectivity in macrophages and T lymphocytes remains unclear. Experiments in HIV-1 infected macrophages confirmed the presence of a Nef:Hck complex which was dependent on the Nef proline repeat motif. The proline repeat motif of Nef also enhanced both HIV-1 infection and replication in macrophages, and was required for incorporation of Hck into viral particles. Unexpectedly, wild-type Hck inhibited infection of macrophages, but Hck was shown to enhance infection of primary T lymphocytes. These results indicate that the interaction between Nef and Hck is important for Nef-dependent modulation of viral infectivity. Hck-dependent enhancement of HIV-1 infection of T cells suggests that Nef-Hck interaction may contribute to the spread of HIV-1 infection from macrophages to T cells by modulating events in the producer cell, virion and target cell.

  13. Three-dimensional reconstructions of the bacteriophage CUS-3 virion reveal a conserved coat protein I-domain but a distinct tailspike receptor-binding domain

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    Parent, Kristin N., E-mail: kparent@msu.edu [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0378 (United States); Tang, Jinghua; Cardone, Giovanni [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0378 (United States); Gilcrease, Eddie B. [University of Utah School of Medicine, Division of Microbiology and Immunology, Department of Pathology, Salt Lake City, UT 84112 (United States); Janssen, Mandy E.; Olson, Norman H. [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0378 (United States); Casjens, Sherwood R., E-mail: sherwood.casjens@path.utah.edu [University of Utah School of Medicine, Division of Microbiology and Immunology, Department of Pathology, Salt Lake City, UT 84112 (United States); Baker, Timothy S., E-mail: tsb@ucsd.edu [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0378 (United States); University of California, San Diego, Division of Biological Sciences, La Jolla, CA, 92093 (United States)

    2014-09-15

    CUS-3 is a short-tailed, dsDNA bacteriophage that infects serotype K1 Escherichia coli. We report icosahedrally averaged and asymmetric, three-dimensional, cryo-electron microscopic reconstructions of the CUS-3 virion. Its coat protein structure adopts the “HK97-fold” shared by other tailed phages and is quite similar to that in phages P22 and Sf6 despite only weak amino acid sequence similarity. In addition, these coat proteins share a unique extra external domain (“I-domain”), suggesting that the group of P22-like phages has evolved over a very long time period without acquiring a new coat protein gene from another phage group. On the other hand, the morphology of the CUS-3 tailspike differs significantly from that of P22 or Sf6, but is similar to the tailspike of phage K1F, a member of the extremely distantly related T7 group of phages. We conclude that CUS-3 obtained its tailspike gene from a distantly related phage quite recently. - Highlights: • Asymmetric and symmetric three-dimensional reconstructions of phage CUS-3 are presented. • CUS-3 major capsid protein has a conserved I-domain, which is found in all three categories of “P22-like phage”. • CUS-3 has very different tailspike receptor binding domain from those of P22 and Sf6. • The CUS-3 tailspike likely was acquired by horizontal gene transfer.

  14. Targeting of arenavirus RNA synthesis by a carboxamide-derivatized aromatic disulfide with virucidal activity.

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    Claudia S Sepúlveda

    Full Text Available Several arenaviruses can cause severe hemorrhagic fever (HF in humans, representing a public health threat in endemic areas of Africa and South America. The present study characterizes the potent virucidal activity of the carboxamide-derivatized aromatic disulfide NSC4492, an antiretroviral zinc finger-reactive compound, against Junín virus (JUNV, the causative agent of Argentine HF. The compound was able to inactivate JUNV in a time and temperature-dependent manner, producing more than 99 % reduction in virus titer upon incubation with virions at 37 °C for 90 min. The ability of NSC4492-treated JUNV to go through different steps of the multiplication cycle was then evaluated. Inactivated virions were able to bind and enter into the host cell with similar efficiency as control infectious particles. In contrast, treatment with NSC4492 impaired the capacity of JUNV to drive viral RNA synthesis, as measured by quantitative RT-PCR, and blocked viral protein expression, as determined by indirect immunofluorescence. These results suggest that the disulfide NSC4492 targets on the arenavirus replication complex leading to impairment in viral RNA synthesis. Additionally, analysis of VLP produced in NSC4492-treated cells expressing JUNV matrix Z protein revealed that the compound may interact with Z resulting in an altered aggregation behavior of this protein, but without affecting its intrinsic self-budding properties. The potential perspectives of NSC4492 as an inactivating vaccinal compound for pathogenic arenaviruses are discussed.

  15. Targeting of arenavirus RNA synthesis by a carboxamide-derivatized aromatic disulfide with virucidal activity.

    Science.gov (United States)

    Sepúlveda, Claudia S; García, Cybele C; Levingston Macleod, Jesica M; López, Nora; Damonte, Elsa B

    2013-01-01

    Several arenaviruses can cause severe hemorrhagic fever (HF) in humans, representing a public health threat in endemic areas of Africa and South America. The present study characterizes the potent virucidal activity of the carboxamide-derivatized aromatic disulfide NSC4492, an antiretroviral zinc finger-reactive compound, against Junín virus (JUNV), the causative agent of Argentine HF. The compound was able to inactivate JUNV in a time and temperature-dependent manner, producing more than 99 % reduction in virus titer upon incubation with virions at 37 °C for 90 min. The ability of NSC4492-treated JUNV to go through different steps of the multiplication cycle was then evaluated. Inactivated virions were able to bind and enter into the host cell with similar efficiency as control infectious particles. In contrast, treatment with NSC4492 impaired the capacity of JUNV to drive viral RNA synthesis, as measured by quantitative RT-PCR, and blocked viral protein expression, as determined by indirect immunofluorescence. These results suggest that the disulfide NSC4492 targets on the arenavirus replication complex leading to impairment in viral RNA synthesis. Additionally, analysis of VLP produced in NSC4492-treated cells expressing JUNV matrix Z protein revealed that the compound may interact with Z resulting in an altered aggregation behavior of this protein, but without affecting its intrinsic self-budding properties. The potential perspectives of NSC4492 as an inactivating vaccinal compound for pathogenic arenaviruses are discussed.

  16. Interaction of poxvirus intracellular mature virion proteins with the TPR domain of kinesin light chain in live infected cells revealed by two-photon-induced fluorescence resonance energy transfer fluorescence lifetime imaging microscopy.

    Science.gov (United States)

    Jeshtadi, Ananya; Burgos, Pierre; Stubbs, Christopher D; Parker, Anthony W; King, Linda A; Skinner, Michael A; Botchway, Stanley W

    2010-12-01

    Using two-photon-induced fluorescence lifetime imaging microscopy, we corroborate an interaction (previously demonstrated by yeast two-hybrid domain analysis) of full-length vaccinia virus (VACV; an orthopoxvirus) A36 protein with the cellular microtubule motor protein kinesin. Quenching of enhanced green fluorescent protein (EGFP), fused to the C terminus of VACV A36, by monomeric red fluorescent protein (mDsRed), fused to the tetratricopeptide repeat (TPR) domain of kinesin, was observed in live chicken embryo fibroblasts infected with either modified vaccinia virus Ankara (MVA) or wild-type fowlpox virus (FWPV; an avipoxvirus), and the excited-state fluorescence lifetime of EGFP was reduced from 2.5 ± 0.1 ns to 2.1 ± 0.1 ns due to resonance energy transfer to mDsRed. FWPV does not encode an equivalent of intracellular enveloped virion surface protein A36, yet it is likely that this virus too must interact with kinesin to facilitate intracellular virion transport. To investigate possible interactions between innate FWPV proteins and kinesin, recombinant FWPVs expressing EGFP fused to the N termini of FWPV structural proteins Fpv140, Fpv168, Fpv191, and Fpv198 (equivalent to VACV H3, A4, p4c, and A34, respectively) were generated. EGFP fusions of intracellular mature virion (IMV) surface protein Fpv140 and type II membrane protein Fpv198 were quenched by mDsRed-TPR in recombinant FWPV-infected cells, indicating that these virion proteins are found within 10 nm of mDsRed-TPR. In contrast, and as expected, EGFP fusions of the IMV core protein Fpv168 did not show any quenching. Interestingly, the p4c-like protein Fpv191, which demonstrates late association with preassembled IMV, also did not show any quenching.

  17. Essential role of the unordered VP2 n-terminal domain of the parvovirus MVM capsid in nuclear assembly and endosomal enlargement of the virion fivefold channel for cell entry

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Martinez, Cristina; Grueso, Esther [Centro de Biologia Molecular Severo Ochoa (CSIC-UAM), Universidad Autonoma de Madrid, 28049 Cantoblanco, Madrid (Spain); Carroll, Miles [Health Protection Agency, Centre for Emergency Preparedness and Response, Porton Down, Salisbury SP4 OJG, Wilts (United Kingdom); Rommelaere, Jean [Deutsches Krebsforschungszentrum Division F010, Im Neuenheimer Feld 242, D-69120 Heidelberg (Germany); Almendral, Jose M., E-mail: jmalmendral@cbm.uam.es [Centro de Biologia Molecular Severo Ochoa (CSIC-UAM), Universidad Autonoma de Madrid, 28049 Cantoblanco, Madrid (Spain)

    2012-10-10

    The unordered N-termini of parvovirus capsid proteins (Nt) are translocated through a channel at the icosahedral five-fold axis to serve for virus traffick. Heterologous peptides were genetically inserted at the Nt of MVM to study their functional tolerance to manipulations. Insertion of a 5T4-single-chain antibody at VP2-Nt (2Nt) yielded chimeric capsid subunits failing to enter the nucleus. The VEGFR2-binding peptide (V1) inserted at both 2Nt and VP1-Nt efficiently assembled in virions, but V1 disrupted VP1 and VP2 entry functions. The VP2 defect correlated with restricted externalization of V1-2Nt out of the coat. The specific infectivity of MVM and wtVP-pseudotyped mosaic MVM-V1 virions, upon heating and/or partial 2Nt cleavage, demonstrated that some 2Nt domains become intracellularly translocated out of the virus shell and cleaved to initiate entry. The V1 insertion defines a VP2-driven endosomal enlargement of the channel as an essential structural rearrangement performed by the MVM virion to infect.

  18. Study on the Safety of Influenza A/H1N1 Split- virion Vaccine%甲型H1N1流行性感冒病毒裂解疫苗的安全性研究

    Institute of Scientific and Technical Information of China (English)

    李瑞芳; 李建坡; 李琦; 张连山; 张富斌; 尹增慧

    2012-01-01

    Objective To evaluate the safety of influenza A/H1N1 split -virion vaccine. Methods Active surveillance sites were set up. AEFI cases with influenza A/H1N1 split - virion vaccine and seasonal influenza vaccine in Handan City were collected through National Surveillance System for Suspected Adverse Events Following Immunization (AEFI). The related data were analyzed epidemiologically using descriptive methods. Results The incidence rate of reported AEFI cases with influenza A/H1N1 split- virion vaccine in Handan City was 14. 64/100,000, and the general reactions were dominant, accounting for 88.57%. The predominant symptom was fever below 38.5 degrees C. No serious adverse reactions and preventive inoculation accidents occurred. The incidence rale of AEFI cases with influenza A/H1N1 split - virion vaccine reported by the surveillance sites was 752.63/100,000, all clinical symptoms were general reactions and the major manifestation was fever. The incidence rate of AEFI cases with seasonal influenza vaccine reported by the surveillance sites was 203.14/100,000, all clinical symptoms and the major manifestation were the same as above. Conclusions The incidence rate of AEFI cases with influenza A/H1N1 split -virion vaccine is higher than that of AEFI cases with seasonal influenza vaccine, but the rates are both lower than the EU standards. General reactions dominate over AEFI cases with influenza A/H1N1 split - virion vaccine, and moreover, fever is the main manifestation. Influenza A/H1N1 split - virion vaccine is safe.%目的 评价甲型H1N1流行性感冒裂解疫苗(简称甲流疫苗)的安全性.方法 设立主动监测点,通过全国疑似预防接种异常反应信息管理系统,收集全市接种甲流疫苗和主动监测点接种季节性流感疫苗后的AEFI个案信息,采用描述性方法对相关指标进行流行病学分析.结果 邯郸市常规报告接种甲流疫苗后AEFI发生率14.64/10万,以一般反应为主,占88.57%,症状主要为38

  19. Comparative analysis of the mosaic genomes of tailed archaeal viruses and proviruses suggests common themes for virion architecture and assembly with tailed viruses of bacteria.

    Science.gov (United States)

    Krupovic, Mart; Forterre, Patrick; Bamford, Dennis H

    2010-03-19

    Tailed double-stranded DNA viruses (order Caudovirales) represent the dominant morphotype among viruses infecting bacteria. Analysis and comparison of complete genome sequences of tailed bacterial viruses provided insights into their origin and evolution. Structural and genomic studies have unexpectedly revealed that tailed bacterial viruses are evolutionarily related to eukaryotic herpesviruses. Organisms from the third domain of life, Archaea, are also infected by viruses that, in their overall morphology, resemble tailed viruses of bacteria. However, high-resolution structural information is currently unavailable for any of these viruses, and only a few complete genomes have been sequenced so far. Here we identified nine proviruses that are clearly related to tailed bacterial viruses and integrated into chromosomes of species belonging to four different taxonomic orders of the Archaea. This more than doubled the number of genome sequences available for comparative studies. Our analyses indicate that highly mosaic tailed archaeal virus genomes evolve by homologous and illegitimate recombination with genomes of other viruses, by diversification, and by acquisition of cellular genes. Comparative genomics of these viruses and related proviruses revealed a set of conserved genes encoding putative proteins similar to virion assembly and maturation, as well as genome packaging proteins of tailed bacterial viruses and herpesviruses. Furthermore, fold prediction and structural modeling experiments suggest that the major capsid proteins of tailed archaeal viruses adopt the same topology as the corresponding proteins of tailed bacterial viruses and eukaryotic herpesviruses. Data presented in this study strongly support the hypothesis that tailed viruses infecting archaea share a common ancestry with tailed bacterial viruses and herpesviruses.

  20. Molecular epizootiology and evolution of the glycoprotein and non-virion protein genes of infectious hematopoietic necrosis virus, a fish rhabdovirus

    Science.gov (United States)

    Nichol, Stuart T.; Rowe, Joan E.; Winton, James R.

    1995-01-01

    Infectious hematopoietic necrosis virus (IHNV) causes a highly lethal, economically important disease of salmon and trout. The virus is enzootic throughout western North America, and has been spread to Asia and Europe. The nucleotide sequences of the glycoprotein (G) and non-virion (NV) genes of 12 diverse IHNV isolates were determined in order to examine the molecular epizootiology of IHN, the primary structure and conservation of NV, and the evolution of the virus. The G and NV genes and their encoded proteins were highly conserved, with a maximum pairwise nucleotide divergence of 3.6 and 4.4.%, and amino acid divergence of 3.7 and 6.2%, respectively. Conservation of NV protein sequence (111 amino acids in length) confirms that the protein is functional and plays an important role in virus replication. The phylogenetic relationship of viruses was found to correlate with the geographic origin of virus isolates rather than with host species or time of isolation. These data are consistent with stable maintenance of virus in enzootic foci. Two main IHNV genetic lineages were identified; one in the Columbia River Basin (Oregon, Washington and Idaho), the other in the Sacramento River Basin (California). The first major IHNV outbreak in chinook salmon in 1973 in the Columbia River was genetically linked to importation of virus-infected fish eggs from the Sacramento River where outbreaks in chinook salmon are common. However, the introduced virus apparently did not persist, subsequent virus outbreaks in Columbia River chinook salmon being associated with Columbia River genetic lineages. In general, virus monoclonal antibody reactivity profiles and phylogenetic relationships correlated well.

  1. Amphipathic alpha-helices and putative cholesterol binding domains of the influenza virus matrix M1 protein are crucial for virion structure organisation.

    Science.gov (United States)

    Tsfasman, Tatyana; Kost, Vladimir; Markushin, Stanislav; Lotte, Vera; Koptiaeva, Irina; Bogacheva, Elena; Baratova, Ludmila; Radyukhin, Victor

    2015-12-02

    The influenza virus matrix M1 protein is an amphitropic membrane-associated protein, forming the matrix layer immediately beneath the virus raft membrane, thereby ensuring the proper structure of the influenza virion. The objective of this study was to elucidate M1 fine structural characteristics, which determine amphitropic properties and raft membrane activities of the protein, via 3D in silico modelling with subsequent mutational analysis. Computer simulations suggest the amphipathic nature of the M1 α-helices and the existence of putative cholesterol binding (CRAC) motifs on six amphipathic α-helices. Our finding explains for the first time many features of this protein, particularly the amphitropic properties and raft/cholesterol binding potential. To verify these results, we generated mutants of the A/WSN/33 strain via reverse genetics. The M1 mutations included F32Y in the CRAC of α-helix 2, W45Y and W45F in the CRAC of α-helix 3, Y100S in the CRAC of α-helix 6, M128A and M128S in the CRAC of α-helix 8 and a double L103I/L130I mutation in both a putative cholesterol consensus motif and the nuclear localisation signal. All mutations resulted in viruses with unusual filamentous morphology. Previous experimental data regarding the morphology of M1-gene mutant influenza viruses can now be explained in structural terms and are consistent with the pivotal role of the CRAC-domains and amphipathic α-helices in M1-lipid interactions.

  2. Clostridium perfringens bacteriophages ΦCP39O and ΦCP26F: genomic organization and proteomic analysis of the virions.

    Science.gov (United States)

    Seal, Bruce S; Fouts, Derrick E; Simmons, Mustafa; Garrish, Johnna K; Kuntz, Robin L; Woolsey, Rebekah; Schegg, Kathleen M; Kropinski, Andrew M; Ackermann, Hans-W; Siragusa, Gregory R

    2011-01-01

    Poultry intestinal material, sewage and poultry processing drainage water were screened for virulent Clostridium perfringens bacteriophages. Viruses isolated from broiler chicken offal washes (O) and poultry feces (F), designated ΦCP39O and ΦCP26F, respectively, produced clear plaques on host strains. Both bacteriophages had isometric heads of 57 nm in diameter with 100-nm non-contractile tails characteristic of members of the family Siphoviridae in the order Caudovirales. The double-strand DNA genome of bacteriophage ΦCP39O was 38,753 base pairs (bp), while the ΦCP26F genome was 39,188 bp, with an average GC content of 30.3%. Both viral genomes contained 62 potential open reading frames (ORFs) predicted to be encoded on one strand. Among the ORFs, 29 predicted proteins had no known similarity while others encoded putative bacteriophage capsid components such as a pre-neck/appendage, tail, tape measure and portal proteins. Other genes encoded a predicted DNA primase, single-strand DNA-binding protein, terminase, thymidylate synthase and a transcription factor. Potential lytic enzymes such as a fibronectin-binding autolysin, an amidase/hydrolase and a holin were encoded in the viral genomes. Several ORFs encoded proteins that gave BLASTP matches with proteins from Clostridium spp. and other Gram-positive bacterial and bacteriophage genomes as well as unknown putative Collinsella aerofaciens proteins. Proteomics analysis of the purified viruses resulted in the identification of the putative pre-neck/appendage protein and a minor structural protein encoded by large open reading frames. Variants of the portal protein were identified, and several mycobacteriophage gp6-like protein variants were detected in large amounts relative to other virion proteins. The predicted amino acid sequences of the pre-neck/appendage proteins had major differences in the central portion of the protein between the two phage gene products. Based on phylogenetic analysis of the large

  3. Inactivated split-virion seasonal influenza vaccine (Fluarix): a review of its use in the prevention of seasonal influenza in adults and the elderly.

    Science.gov (United States)

    Curran, Monique P; Leroux-Roels, Isabel

    2010-08-20

    Fluarix is a trivalent, inactivated, split-virion influenza vaccine containing 15 microg haemagglutinin from each of the three influenza virus strains (including an H1N1 influenza A virus subtype, an H3N2 influenza A virus subtype and an influenza B virus) that are expected to be circulating in the up-coming influenza season. Fluarix is highly immunogenic in healthy adults and elderly, and exceeds the criteria that make it acceptable for licensure in various regions (including the US and Europe). In a large, phase III, placebo-controlled, double-blind trial conducted in the US (2004/2005) in subjects aged 18-64 years, postvaccination seroconversion rates against the H1N1, H3N2 and B antigens were 60-78% and respective postvaccination seroprotection rates were 97-99% in Fluarix recipients. Another phase III trial conducted in the US (2005/2006) established the noninferiority of Fluarix versus another trivalent inactivated influenza virus vaccine in subjects aged >or=18 years, including a subgroup of elderly subjects. In annual European registration trials, Fluarix has consistently exceeded the immunogenicity criteria set by the EU Committee for Medicinal Products for Human Use for adults and the elderly. Fluarix demonstrated immunogenicity in small, open-label studies in at-risk subjects. During a year when the vaccine was well matched to the circulating strain, Fluarix demonstrated efficacy against culture-confirmed influenza A and/or B in a placebo-controlled trial in adults aged 18-64 years. In addition, Fluarix vaccination of pregnant women demonstrated efficacy in reducing the rate of laboratory-confirmed influenza in the infants and reducing febrile respiratory illnesses in the mothers and their new-born infants in a randomized trial. Fluarix was generally well tolerated in adults and the elderly in well designed clinical trials and in the annual European registration trials, with most local and general adverse events being transient and mild to moderate in

  4. The research and development of quadrivalent influenza vaccine (split virion), inactivated%四价流感病毒裂解灭活疫苗的研制

    Institute of Scientific and Technical Information of China (English)

    吴建华; 路福平; 赵越; 王剑飞; 帅旗; 张赟; 朱实惠; 缪小翠; 赵静

    2015-01-01

    Objective To research and development of quadrivalent influenza vaccine,improve the ability of the vaccine to protect people.Methods Using the influenza vaccine strains recommended by WHO,adopt zone centrifugation and molecular sieve chromatography purification process to produce influenza vaccines and verify the vaccine in accordance with the requirements of Chinese Pharmacopoeia (2010 Edition 3),and then continue to test the immunogenicity and animal allergy reaction.Results The indicators are in line with the "China Pharmacopoeia"2010 three edition" influenza vaccine (split virion)" under the registration standard.Immunogenicity test results show that adding a B virus antigen in the trivalent influenza vaccine,the new increased antigen and original antigen have no antagonistic effect and does not affect the related antibody;allergen test showed that the increase in antigen kinds and amounts does not aggravate the local and systemic adverse reactions.Conclusions This production technology is mature,stable and reliable,and can produce high quality suitable for people with safe and effective vaccine.%目的 研制四价流感疫苗,提高疫苗对人群的保护能力.方法 用WHO推荐的流感疫苗株采用先区带离心再分子筛层析纯化的工艺制备流感疫苗,按中国药典(2010年版三部)的要求进行全项检定,并进行免疫原性试验和动物过敏性试验.结果 各项指标均符合《中国药典》2010年版三部《流感病毒裂解疫苗》项下申报注册标准.免疫原性试验结果表明在现有三价流感疫苗中增加一个B型病毒抗原后,新增抗原与原有抗原无拮抗作用,不影响相关抗体的产生.过敏原性试验表明抗原种类和总量的增加,不会加重局部和全身的副作用反应.结论 本生产工艺成熟、稳定、可靠,可制备高质量适合人用的安全、有效的流感疫苗.

  5. Rapid dissociation of HIV-1 from cultured cells severely limits infectivity assays, causes the inactivation ascribed to entry inhibitors, and masks the inherently high level of infectivity of virions.

    Science.gov (United States)

    Platt, Emily J; Kozak, Susan L; Durnin, James P; Hope, Thomas J; Kabat, David

    2010-03-01

    By using immunofluorescence microscopy to observe and analyze freshly made HIV-1 virions adsorbed onto cells, we found that they are inherently highly infectious, rather than predominantly defective as previously suggested. Surprisingly, polycations enhance titers 20- to 30-fold by stabilizing adsorption and preventing a previously undescribed process of rapid dissociation, strongly implying that infectivity assays for many viruses are limited not only by inefficient virus diffusion onto cells but also by a postattachment race between entry and dissociation. This kinetic competition underlies inhibitory effects of CCR5 antagonists and explains why adaptive HIV-1 mutations overcome many cell entry limitations by accelerating entry.

  6. Site-Directed Mutagenesis of the Virion Host Shutoff Gene (UL41) of Herpes Simplex Virus (HSV): Analysis of Functional Differences between HSV Type 1 (HSV-1) and HSV-2 Alleles

    OpenAIRE

    Everly, David N.; Read, G. Sullivan

    1999-01-01

    During lytic herpes simplex virus (HSV) infections, the HSV virion host shutoff protein (UL41) accelerates the turnover of host and viral mRNAs. Although the UL41 polypeptides from HSV type 1 (HSV-1) strain KOS and HSV-2 strain 333 are 87% identical, HSV-2 strains generally shut off the host more rapidly and completely than HSV-1 strains. In a previous study, we identified three regions of the HSV-2 UL41 polypeptide (amino acids 1 to 135, 208 to 243, and 365 to 492) that enhance the activity ...

  7. Comparative Analysis of gO Isoforms Reveals that Strains of Human Cytomegalovirus Differ in the Ratio of gH/gL/gO and gH/gL/UL128-131 in the Virion Envelope

    Science.gov (United States)

    Zhou, Momei; Yu, Qin; Wechsler, Anya

    2013-01-01

    Herpesvirus glycoprotein complex gH/gL provides a core entry function through interactions with the fusion protein gB and can also influence tropism through receptor interactions. The Epstein-Barr virus gH/gL and gH/gL/gp42 serve both functions for entry into epithelial and B cells, respectively. Human cytomegalovirus (HCMV) gH/gL can be bound by the UL128-131 proteins or gO. The phenotypes of gO and UL128-131 mutants suggest that gO-gH/gL interactions are necessary for the core entry function on all cell types, whereas the binding of UL128-131 to gH/gL likely relates to a distinct receptor-binding function for entry into some specific cell types (e.g., epithelial) but not others (e.g., fibroblasts and neurons). There are at least eight isoforms of gO that differ by 10 to 30% of amino acids, and previous analysis of two HCMV strains suggested that some isoforms of gO function like chaperones, disassociating during assembly to leave unbound gH/gL in the virion envelope, while others remain bound to gH/gL. For the current report, we analyzed the gH/gL complexes present in the virion envelope of several HCMV strains, each of which encodes a distinct gO isoform. Results indicate that all strains of HCMV contain stable gH/gL/gO trimers and gH/gL/UL128-131 pentamers and little, if any, unbound gH/gL. TR, TB40/e, AD169, and PH virions contained vastly more gH/gL/gO than gH/gL/UL128-131, whereas Merlin virions contained mostly gH/gL/UL128-131, despite abundant unbound gO remaining in the infected cells. Suppression of UL128-131 expression during Merlin replication dramatically shifted the ratio toward gH/gL/gO. These data suggest that Merlin gO is less efficient than other gO isoforms at competing with UL128-131 for binding to gH/gL. Thus, gO diversity may influence the pathogenesis of HCMV through effects on the assembly of the core versus tropism gH/gL complexes. PMID:23804643

  8. Early shutoff of host protein synthesis in cells infected with herpes simplex viruses.

    Science.gov (United States)

    Matis, J; Kúdelová, M

    2001-01-01

    Herpes simplex viruses 1 (HSV-1) and 2 (HSV-2) are capable of suppressing the host cell protein synthesis even without viral gene expression. This phenomenon is known as the early shutoff or as the virion-associated host shutoff (vhs) to emphasize that it is mediated by a component of infecting virions which is a product of the UL41 (vhs) gene. The UL41 encoded protein is a functional tegument protein also present in light (L) particles and is not essential for virus replication. The major product of UL41 gene is a 58 K phosphoprotein. At least two forms of UL41 protein differing in the extent of phosphorylation are present in HSV-1-infected cells. HSV-2 compared to HSV-1 strains display a stronger vhs phenotype. However, in superinfection experiments the less strong vhs phenotype is dominant. UL41 protein triggers disruption of polysomes and rapid degradation of all host and viral mRNAs and blocks a reporter gene expression without other HSVs proteins. The available evidence suggests that UL41 protein is either itself a ribonuclease (RNase) or a subunit of RNase that contains also one or more cellular subunits. UL41 protein is capable of interacting with a transactivator of an alpha-gene, the alpha-transinducing factor (alpha-TIF). Interaction of UL41 protein with alpha-TIF down regulates the UL41 (vhs) gene activity during lytic infection. The possible role of other viral proteins in the shutoff is discussed.

  9. Lifestyle-related diseases of the digestive system: a new in vitro model of hepatitis C virion production: application of basic research on hepatitis C virus to clinical medicine.

    Science.gov (United States)

    Saito, Satoru; Heller, Theo; Yoneda, Masato; Takahashi, Hirokazu; Nakajima, Atsushi; Liang, Jake T

    2007-10-01

    The hepatitis C virus (HCV) is an enveloped virus with a single positive-strand RNA genome of about 9.6 kb. It is a major cause of liver disease worldwide. Clear understanding of the viral life cycle has been hampered by the lack of a robust cell culture system. While the development of the HCV replicon system was a major breakthrough, infectious virions could not be produced with the replicon system. Recently, several groups have reported producing HCV virions using in vitro systems. One of these is a replicon system, but with the special genotype 2a strain JFH-1. Another is a DNA transfection system, with the construct containing the cDNA of the known infectious HCV genotype 1b flanked by two ribozymes. The development of these models further extends the repertoire of tools available for the study of HCV biology, and in particular, they may help to elucidate the molecular details of hepatitis C viral assembly and release. This review discusses the progression of experimental strategies related to HCV and how these strategies may be applied to clinical medicine.

  10. Organic Synthesis

    OpenAIRE

    Romea, Pedro

    2014-01-01

    Organic Synthesis is a one-semester course of the fourth year of the Chemistry Degree at the Universitat de Barcelona. This course covers the most important transformations in Organic Chemistry, including a short introduction to the Retrosynthetic Analysis. The aim is to provide a solid knowledge of the main reactions and their mechanism, which could later be improved during Master studies.

  11. Mechanisms of metal mineralization on virus templates for nanorod synthesis

    Science.gov (United States)

    Adigun, Oluwamayowa O.

    Solution synthesis of nanorods is currently an important area of study due to the precision required to engender advantages in a wide range of fields. Viruses provide a template for synthesis in order to form uniform metal nanorods at mild operating conditions, without the use of expensive technology. In recent years, many materials involving the Tobacco mosaic virus (TMV) and its variants have been synthesized in attempts to produce high quality nanomaterials. However, the underlying processes involved in virion mineralization have not been sufficiently studied to allow for directed synthesis. The fundamental study of the hydrothermal synthesis of palladium on biotemplates, which produces uniform, controllable, monodisperse palladium nanorods, is of interest in this thesis. Three different experimental studies are outlined in this thesis. In situ X-ray absorption spectroscopy (XAS) was employed in order to characterize the reduction and growth mechanisms of palladium (Pd) on the surface of genetically engineered TMV. XAS, via XANES and EXAFS analysis was combined with TEM to confirm an autocatalytic reduction, mediated by the TMV1Cys surface. This reduction interestingly proceeds via two first order regimes, which result in two linear growth regimes as spherical palladium nanoparticles are formed. Results in this project served as an entryway into fundamentally understanding virus-mediated reduction and the relationship between the underlying reduction and growth processes governing mineralization. Pd biomineralization was further elucidated by reframing it within commonly known molecular processes. These included the individual adsorption, reduction, and nanocrystal growth processes, which simultaneously occur during the hydrothermal synthesis on TMV. The adsorption of precursor and reduction of palladium were decoupled through UV-Vis Spectroscopy and in situ XAS studies. The role of additional cysteine (Cys) residues, ionic strength, and coating density on the

  12. Genetic mutation analysis of HBV covalently closed circular DNA in peripheral blood mononuclear cells from chronic hepatitis B patients with nucleos(tide analog-resistant mutations in serum virions

    Directory of Open Access Journals (Sweden)

    Zhong-bin LI

    2012-06-01

    Full Text Available Objective  To analyze the characteristics of genetic mutations in reverse-transcriptase (RT domain of HBV covalently closed circular DNA (cccDNA in peripheral blood mononuclear cells (PBMCs obtained from chronic hepatitis B (CHB patients with drug-resistant mutations in serum virions during nucleoside/nucleotide analog (NA therapy. Methods  A total of 30 CHB patients admitted to 302 Hospital of PLA from July 2010 to August 2011 were included in this study. All the patients were confirmed to harbor the drug-resistant mutations in serum virions during an NA therapy longer than 6 months. Total DNA was extracted from PBMCs isolated from 30 whole blood samples at the same time point as that of serum analysis. Plasmid-safe ATP-dependent DNase (PSAD digestion in combination with rolling circle amplification and gap-spanning semi-nested PCR were used to amplify the RT region of HBV cccDNA. NA-resistant-associated mutations were analyzed at nine sites. Results  HBV cccDNA was efficiently amplified in 16 out of 30 (53.3% PBMC samples, and the detection rate was not correlated with HBeAg-positive rate, serum ALT level or HBV DNA load. Five of 16 (31.3% patients were sustained to have genotype B HBV infection, and 11 of 16 (68.8% were of genotype C HBV infection, and the result was consistent with the genotyping results using serum HBV. Different from drug-resistant mutations detected in the serum virions, the viruses detected in HBV cccDNA of 16 PBMC samples were all wild-type viruses without NA-resistant-associated mutations in RT region. Conclusions  During NA antiviral treatment, if drug-resistant mutations occur in serum HBV DNA of CHB patients, the dominant species of HBV cccDNA in PBMCs from the same patient is still the original wild-type strains. It is speculated that PBMCs might be the potential "repository" of HBV wild-type strain in vivo.

  13. Vaccinia mature virus fusion regulator A26 protein binds to A16 and G9 proteins of the viral entry fusion complex and dissociates from mature virions at low pH.

    Science.gov (United States)

    Chang, Shu-Jung; Shih, Ao-Chun; Tang, Yin-Liang; Chang, Wen

    2012-04-01

    Vaccinia mature virus enters cells through either endocytosis or plasma membrane fusion, depending on virus strain and cell type. Our previous results showed that vaccinia virus mature virions containing viral A26 protein enter HeLa cells preferentially through endocytosis, whereas mature virions lacking A26 protein enter through plasma membrane fusion, leading us to propose that A26 acts as an acid-sensitive fusion suppressor for mature virus (S. J. Chang, Y. X. Chang, R. Izmailyan R, Y. L. Tang, and W. Chang, J. Virol. 84:8422-8432, 2010). In the present study, we investigated the fusion suppression mechanism of A26 protein. We found that A26 protein was coimmunoprecipitated with multiple components of the viral entry-fusion complex (EFC) in infected HeLa cells. Transient expression of viral EFC components in HeLa cells revealed that vaccinia virus A26 protein interacted directly with A16 and G9 but not with G3, L5 and H2 proteins of the EFC components. Consistently, a glutathione S-transferase (GST)-A26 fusion protein, but not GST, pulled down A16 and G9 proteins individually in vitro. Together, our results supported the idea that A26 protein binds to A16 and G9 protein at neutral pH contributing to suppression of vaccinia virus-triggered membrane fusion from without. Since vaccinia virus extracellular envelope proteins A56/K2 were recently shown to bind to the A16/G9 subcomplex to suppress virus-induced fusion from within, our results also highlight an evolutionary convergence in which vaccinia viral fusion suppressor proteins regulate membrane fusion by targeting the A16 and G9 components of the viral EFC complex. Finally, we provide evidence that acid (pH 4.7) treatment induced A26 protein and A26-A27 protein complexes of 70 kDa and 90 kDa to dissociate from mature virions, suggesting that the structure of A26 protein is acid sensitive.

  14. Dynamic Analysis of an HIV Model with Delayed Immune Response and Virions%一类具有免疫时滞和病毒颗粒的HIV 模型的动力学性态分析

    Institute of Scientific and Technical Information of China (English)

    王海彬; 李云飞; 刘云

    2013-01-01

    Considering the cure of the infected cells and absorption effects of the uninfected cells, an HIV infection model with delayed immune response and virions is investigated.The local sta-bility of each equilibrium is discussed by analyzing the corresponding characteristic equations. Based on the normal form theory and center manifold,the formulas for determining the direction of Hopf bifurcation and the stability of bifurcated periodic solutions are confirmed.Moreover,by constructing proper Lyapunov functional,the global stability of the infection-free equilibrium is discussed.%考虑感染细胞的治愈和未感染细胞吸收作用的影响,研究一类具有免疫时滞和病毒颗粒的 HIV 模型,通过分析特征方程研究平衡点的局部稳定性,利用规范型理论和中心流行定理得到确定 Hopf 分支方向和分支周期解稳定性的计算公式,并通过构造 Lyapunov 泛函,讨论未感染平衡点的全局稳定性。

  15. Processing, fusogenicity, virion incorporation and CXCR4-binding activity of a feline immunodeficiency virus envelope glycoprotein lacking the two conserved N-glycosylation sites at the C-terminus of the V3 domain.

    Science.gov (United States)

    González, Silvia A; Affranchino, José L

    2016-07-01

    The process of feline immunodeficiency virus (FIV) entry into its target cells is initiated by the association of the surface (SU) subunit of the viral envelope glycoprotein (Env) with the cellular receptors CD134 and CXCR4. This event is followed by the fusion of the viral and cellular membranes, which is mediated by the transmembrane (TM) subunit of Env. We and others have previously demonstrated that the V3 domain of the SU subunit of Env is essential for CXCR4 binding. Of note, there are two contiguous and highly conserved potential N-glycosylation sites ((418)NST(420) and (422)NLT(424)) located at the C-terminal side of the V3 domain. We therefore decided to study the relevance for Env functions of these N-glycosylation motifs and found that disruption of both of them by introducing the N418Q/N422Q double amino acid substitution drastically impairs Env processing into the SU and TM subunits. Moreover, the simultaneous mutation of these N-glycosylation sites prevents Env incorporation into virions and Env-mediated cell-to-cell fusion. Notably, a recombinant soluble version of the SU glycoprotein carrying the double amino acid replacement N418Q/N422Q at the V3 C-terminal side binds to CXCR4 with an efficiency similar to that of wild-type SU.

  16. Generation of H9 T-cells stably expressing a membrane-bound form of the cytoplasmic tail of the Env-glycoprotein: lack of transcomplementation of defective HIV-1 virions encoding C-terminally truncated Env

    Directory of Open Access Journals (Sweden)

    Bosch Valerie

    2006-05-01

    Full Text Available Abstract H9-T-cells do not support the replication of mutant HIV-1 encoding Env protein lacking its long cytoplasmic C-terminal domain (Env-CT. Here we describe the generation of a H9-T-cell population constitutively expressing the HIV-1 Env-CT protein domain anchored in the cellular membrane by it homologous membrane-spanning domain (TMD. We confirmed that the Env-TMD-CT protein was associated with cellular membranes, that its expression did not have any obvious cytotoxic effects on the cells and that it did not affect wild-type HIV-1 replication. However, as measured in both a single-round assay as well as in spreading infections, replication competence of mutant pNL-Tr712, lacking the Env-CT, was not restored in this H9 T-cell population. This means that the Env-CT per se cannot transcomplement the replication block of HIV-1 virions encoding C-terminally truncated Env proteins and suggests that the Env-CT likely exerts its function only in the context of the complete Env protein.

  17. Binding of HIV-1 virions to α4β7 expressing cells and impact of antagonizing α4β7 on HIV-1 infection of primary CD4+ T cells

    Institute of Scientific and Technical Information of China (English)

    Chang; Li; Wei; Jin; Tao; Du; Biao; Wu; Yalan; Liu; Robin; J; Shattock; Qinxue; Hu

    2014-01-01

    HIV-1 envelope glycoprotein is reported to interact with α4β7, an integrin mediating the homing of lymphocytes to gut-associated lymphoid tissue, but the significance of α4β7 in HIV-1 infection remains controversial. Here, using HIV-1 strain Ba L, the gp120 of which was previously shown to be capable of interacting with α4β7, we demonstrated that α4β7 can mediate the binding of whole HIV-1 virions to α4β7-expressing transfectants. We further constructed a cell line stably expressing α4β7 and confirmed the α4β7-mediated HIV-1 binding. In primary lymphocytes with activated α4β7 expression, we also observed significant virus binding which can be inhibited by an anti-α4β7 antibody. Moreover, we investigated the impact of antagonizing α4β7 on HIV-1 infection of primary CD4+ T cells. In α4β7-activated CD4+ T cells, both anti-α4β7 antibodies and introduction of shorthairpin RNAs specifically targeting α4β7 resulted in a decreased HIV-1 infection. Our findings indicate that α4β7 may serve as an attachment factor at least for some HIV-1 strains. The established approach provides a promising means for the investigation of other viral strains to understand the potential roles of α4β7 in HIV-1 infection.

  18. Cyclin F/FBXO1 interacts with HIV-1 Vif and restricts progeny virion infectivity by ubiquitination and proteasomal degradation of Vif through SCF (Cyclin F) E3 ligase machinery.

    Science.gov (United States)

    Augustine, Tracy; Chaudhary, Priyanka; Gupta, Kailash; Islam, Sehbanul; Ghosh, Payel; Santra, Manas Kumar; Mitra, Debashis

    2017-02-09

    Cyclin F, also known as FBXO1, is the largest among all cyclins which oscillates in the cell cycle like other cyclins. Apart from being a G2/M cyclin, Cyclin F functions as the substrate binding subunit of SCFCyclin F E3 ubiquitin ligase. In a gene expression analysis performed to identify novel gene modulations associated with cell cycle dysregulation during HIV-1 infection in CD4+ T cells, we observed down-regulation of Cyclin F (CCNF) gene. Later, using gene over expression and knockdown studies, we identified that Cyclin F negatively influences HIV-1 viral infectivity without any significant impact on virus production. Subsequently, we found that Cyclin F negatively regulates the expression of viral protein, Vif (Viral infectivity factor), at the protein level. We also identified a novel host-pathogen interaction between Cyclin F and Vif protein in T cells during HIV-1 infection. Mutational analysis of a Cyclin F-specific amino acid motif in the C-terminal region of Vif shows rescue of the protein from Cyclin F-mediated down-regulation. Subsequently, we have shown that Vif is a novel substrate of the SCFCyclin F E3 ligase, where Cyclin F mediates ubiquitination and proteasomal degradation of Vif through physical interaction. Finally, we have shown that Cyclin F augments APOBEC3G expression through degradation of Vif to regulate infectivity of progeny virions. Taken together, our results demonstrate Cyclin F as a novel F-box protein which functions as an intrinsic cellular regulator of HIV-1 Vif and imparts a negative regulatory effect on maintenance of viral infectivity by restoring APOBEC3G expression.

  19. An MDCK cell culture-derived formalin-inactivated influenza virus whole-virion vaccine from an influenza virus library confers cross-protective immunity by intranasal administration in mice.

    Science.gov (United States)

    Haredy, Ahmad M; Takenaka, Nobuyuki; Yamada, Hiroshi; Sakoda, Yoshihiro; Okamatsu, Masatoshi; Yamamoto, Naoki; Omasa, Takeshi; Ohtake, Hisao; Mori, Yasuko; Kida, Hiroshi; Yamanishi, Koichi; Okamoto, Shigefumi

    2013-07-01

    It is currently impossible to predict the next pandemic influenza virus strain. We have thus established a library of influenza viruses of all hemagglutinin and neuraminidase subtypes and their genes. In this article, we examine the applicability of a rapid production model for the preparation of vaccines against emerging pandemic influenza viruses. This procedure utilizes the influenza virus library, cell culture-based vaccine production, and intranasal administration to induce a cross-protective immune response. First, an influenza virus reassortant from the library, A/duck/Hokkaido/Vac-3/2007 (H5N1), was passaged 22 times (P22) in Madin-Darby canine kidney (MDCK) cells. The P22 virus had a titer of >2 ×10(8) PFU/ml, which was 40 times that of the original strain, with 4 point mutations, which altered amino acids in the deduced protein sequences encoded by the PB2 and PA genes. We then produced a formalin-inactivated whole-virion vaccine from the MDCK cell-cultured A/duck/Hokkaido/Vac-3/2007 (H5N1) P22 virus. Intranasal immunization of mice with this vaccine protected them against challenges with lethal influenza viruses of homologous and heterologous subtypes. We further demonstrated that intranasal immunization with the vaccine induced cross-reactive neutralizing antibody responses against the homotypic H5N1 influenza virus and its antigenic variants and cross-reactive cell-mediated immune responses to the homologous virus, its variants within a subtype, and even an influenza virus of a different subtype. These results indicate that a rapid model for emergency vaccine production may be effective for producing the next generation of pandemic influenza virus vaccines.

  20. mRNA decay during herpes simplex virus (HSV) infections: mutations that affect translation of an mRNA influence the sites at which it is cleaved by the HSV virion host shutoff (Vhs) protein.

    Science.gov (United States)

    Shiflett, Lora A; Read, G Sullivan

    2013-01-01

    During lytic infections, the herpes simplex virus (HSV) virion host shutoff (Vhs) endoribonuclease degrades many host and viral mRNAs. Within infected cells it cuts mRNAs at preferred sites, including some in regions of translation initiation. Vhs binds the translation initiation factors eIF4H, eIF4AI, and eIF4AII, suggesting that its mRNA degradative function is somehow linked to translation. To explore how Vhs is targeted to preferred sites, we examined the in vitro degradation of a target mRNA in rabbit reticulocyte lysates containing in vitro-translated Vhs. Vhs caused rapid degradation of mRNAs beginning with cleavages at sites in the first 250 nucleotides, including a number near the start codon and in the 5' untranslated region. Ligation of the ends to form a circular mRNA inhibited Vhs cleavage at the same sites at which it cuts capped linear molecules. This was not due to an inability to cut any circular RNA, since Vhs cuts circular mRNAs containing an encephalomyocarditis virus (EMCV) internal ribosome entry site (IRES) at the same sites as linear molecules with the IRES. Cutting linear mRNAs at preferred sites was augmented by the presence of a 5' cap. Moreover, mutations that altered the 5' proximal AUG abolished Vhs cleavage at nearby sites, while mutations that changed sequences surrounding the AUG to improve their match to the Kozak consensus sequence enhanced Vhs cutting near the start codon. The results indicate that mutations in an mRNA that affect its translation affect the sites at which it is cut by Vhs and suggest that Vhs is directed to its preferred cut sites during translation initiation.

  1. The virion host shutoff protein of herpes simplex virus 1 blocks the replication-independent activation of NF-κB in dendritic cells in the absence of type I interferon signaling.

    Science.gov (United States)

    Cotter, Christopher R; Kim, Won-keun; Nguyen, Marie L; Yount, Jacob S; López, Carolina B; Blaho, John A; Moran, Thomas M

    2011-12-01

    Immune evasion is a defining feature of the virus-host relationship. During infection, herpes simplex virus type 1 (HSV-1) utilizes multiple proteins to manipulate the host immune response. In the present study, we investigated the mechanism by which the virion host shutoff (vhs) protein blocks the activation of dendritic cells (DCs). Previously, we found that coinfection of wild-type HSV-1 with a panel of RNA viruses resulted in a block to DC activation that was attributable to vhs. These observations led us to hypothesize that the vhs-mediated inhibition was dependent on signaling through the RIG-I-like receptor (RLR) signaling pathway. By examining DCs generated from MAVS (IPS-1) knockout (KO) mice, we determined that RLR/MAVS signaling is not essential for the DC response to HSV-1. We also evaluated the requirement for the type I interferon (IFN) signaling pathway in DC activation following infection with HSV-1 and found that stimulation of DCs with wild-type HSV-1 required intact type I IFN signaling for the production of cytokines, whereas the vhs deletion (vhs(-)) mutant virus activated DCs without the need for exogenous IFN signaling. Comparisons of transcription factor activation in DCs infected with wild-type HSV and the vhs(-) mutant virus revealed that NF-κB activation was inhibited by vhs in the early phase of the infection. In contrast, IRF3 activation was not influenced by vhs. In these studies, measurement of proinflammatory cytokines and type I IFN release from the infected DCs reflected the activation status of these transcription factors. Taken together, the work presented here (i) describes a novel role for the vhs protein as an inhibitor of the early activation of NF-κB during HSV-1 infection of DCs and (ii) offers a mechanistic explanation of how this protein interferes with DC activation.

  2. Technology transfer of oil-in-water emulsion adjuvant manufacturing for pandemic influenza vaccine production in Romania: Preclinical evaluation of split virion inactivated H5N1 vaccine with adjuvant.

    Science.gov (United States)

    Stavaru, Crina; Onu, Adrian; Lupulescu, Emilia; Tucureanu, Catalin; Rasid, Orhan; Vlase, Ene; Coman, Cristin; Caras, Iuliana; Ghiorghisor, Alina; Berbecila, Laurentiu; Tofan, Vlad; Bowen, Richard A; Marlenee, Nicole; Hartwig, Airn; Bielefeldt-Ohmann, Helle; Baldwin, Susan L; Van Hoeven, Neal; Vedvick, Thomas S; Huynh, Chuong; O'Hara, Michael K; Noah, Diana L; Fox, Christopher B

    2016-04-02

    Millions of seasonal and pandemic influenza vaccine doses containing oil-in-water emulsion adjuvant have been administered in order to enhance and broaden immune responses and to facilitate antigen sparing. Despite the enactment of a Global Action Plan for Influenza Vaccines and a multi-fold increase in production capabilities over the past 10 years, worldwide capacity for pandemic influenza vaccine production is still limited. In developing countries, where routine influenza vaccination is not fully established, additional measures are needed to ensure adequate supply of pandemic influenza vaccines without dependence on the shipment of aid from other, potentially impacted first-world countries. Adaptation of influenza vaccine and adjuvant technologies by developing country influenza vaccine manufacturers may enable antigen sparing and corresponding increases in global influenza vaccine coverage capacity. Following on previously described work involving the technology transfer of oil-in-water emulsion adjuvant manufacturing to a Romanian vaccine manufacturing institute, we herein describe the preclinical evaluation of inactivated split virion H5N1 influenza vaccine with emulsion adjuvant, including immunogenicity, protection from virus challenge, antigen sparing capacity, and safety. In parallel with the evaluation of the bioactivity of the tech-transferred adjuvant, we also describe the impact of concurrent antigen manufacturing optimization activities. Depending on the vaccine antigen source and manufacturing process, inclusion of adjuvant was shown to enhance and broaden functional antibody titers in mouse and rabbit models, promote protection from homologous virus challenge in ferrets, and facilitate antigen sparing. Besides scientific findings, the operational lessons learned are delineated in order to facilitate adaptation of adjuvant technologies by other developing country institutes to enhance global pandemic influenza preparedness.

  3. Herpes simplex virus type 1 (HSV-1) strain HSZP host shutoff gene: nucleotide sequence and comparison with HSV-1 strains differing in early shutoff of host protein synthesis.

    Science.gov (United States)

    Vojvodová, A; Matis, J; Kúdelová, M; Rajcáni, J

    1997-01-01

    The UL41 gene of the HSZP strain of herpes simplex virus type 1 (HSV-1) defective with respect to the early shutoff of host protein synthesis was sequenced and compared with the corresponding HSV-1 strain KOS and 17 gene sequences. In comparison with strain 17, nine mutations (base changes) were HSZP specific, five KOS specific and four were common for both strains. Nine mutations caused codon changes. Three of these mapped to the nonconserved regions and the others to the conserved regions of the functional map of UL41 gene. One KOS specific mutation mapped to the region responsible for the binding of the virion host shutoff (vhs) protein to the alpha-transinducing factor (VP16). The possible relationship between mutations and host shutoff function is discussed. The nucleotide sequence data of the UL41 gene of HSZP and KOS have been submitted to the Genbank nucleotide database and have been assigned the accession numbers Z72337 and Z72338.

  4. Total Synthesis of (-)-Conolutinine.

    Science.gov (United States)

    Feng, Xiangyang; Jiang, Guangde; Xia, Zilei; Hu, Jiadong; Wan, Xiaolong; Gao, Jin-Ming; Lai, Yisheng; Xie, Weiqing

    2015-09-18

    The first enantioselective synthesis of (-)-conolutinine was achieved in 10 steps. The synthesis featured a catalytic asymmetric bromocyclization of tryptamine to forge the tricycle intermediate. Hydration of an alkene catalyzed by Co(acac)2 was also employed as a key step to diastereoselectively introduce the tertiary alcohol moiety. The absolute configuration of (-)-conolutinine was established to be (2S,5aS,8aS,13aR) based on this asymmetric total synthesis.

  5. Graphene Synthesis and Characterization

    Science.gov (United States)

    2015-04-08

    AFRL-OSR-VA-TR-2015-0086 Graphene Synthesis and Characterization 130060 Andrea Cortes UNIVERSIDAD TECNICA FEDERICO SANTA MARIA Final Report 04/08...AND SUBTITLE Grant: Graphene synthesis and characterizatión 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-13-1-0060 5c. PROGRAM ELEMENT NUMBER 6...13. SUPPLEMENTARY NOTES 14. ABSTRACT Here is reported graphene synthesis by two methods, Chemical Vapor Deposition (CVD) using Acetylene as a

  6. Synthesis of Mechanisms

    DEFF Research Database (Denmark)

    Hansen, John Michael

    1999-01-01

    These notes describe an automated procedure for analysis and synthesis of mechanisms. The analysis method is based on the body coordinate formulation, and the synthesis is based on applying optimization methods, used to minimize the difference between an actual and a desired behaviour......These notes describe an automated procedure for analysis and synthesis of mechanisms. The analysis method is based on the body coordinate formulation, and the synthesis is based on applying optimization methods, used to minimize the difference between an actual and a desired behaviour...

  7. Synthesis of oligonucleotide phosphorodithioates

    DEFF Research Database (Denmark)

    Beaton, G.; Brill, W. K D; Grandas, A.;

    1991-01-01

    The synthesis of DNA containing sulfur at the two nonbonding internucleotide valencies is reported. Several different routes using either tervalent or pentavalent mononucleotide synthons are described. © 1991....

  8. Synthesis of Psychrophilin E.

    Science.gov (United States)

    Ngen, Sarah T Y; Kaur, Harveen; Hume, Paul A; Furkert, Daniel P; Brimble, Margaret A

    2016-09-02

    The first total synthesis of psychrophilin E, a potent antiproliferative cyclic tripeptide isolated from Aspergillus versicolor ZLN-60, is reported herein. Key features of the synthesis include the installation of an amide bond between the indole-nitrogen of tryptophan and an anthranilic acid residue, and a high yielding macrolactamization of the linear tripeptide to the desired macrocycle.

  9. Programing Structural Synthesis System

    Science.gov (United States)

    Rogers, James L., Jr.

    1986-01-01

    Program aids research in analysis and optimization. Programing Structural Synthesis System (PROSSS2) developed to provide structural-synthesis capability by combining access to SPAR with CONMIN program and set of interface procedures. SPAR is large general-purpose finite-element structural-analysis program, and CONMIN is large general-purpose optimization program. PROSSS2 written in FORTRAN IV for batch execution.

  10. Hamiltonian Algorithm Sound Synthesis

    OpenAIRE

    大矢, 健一

    2013-01-01

    Hamiltonian Algorithm (HA) is an algorithm for searching solutions is optimization problems. This paper introduces a sound synthesis technique using Hamiltonian Algorithm and shows a simple example. "Hamiltonian Algorithm Sound Synthesis" uses phase transition effect in HA. Because of this transition effect, totally new waveforms are produced.

  11. Formal synthesis of (+)-discodermolide.

    Science.gov (United States)

    Francavilla, Charles; Chen, Weichun; Kinder, Frederick R

    2003-04-17

    [structure: see text] Herein we report the formal total synthesis of (+)-discodermolide in 21 steps (longest linear sequence) from commercially available Roche ester. This synthesis features the assembly of C(9-18) and C(19-24) fragments via a metal-chelated aldol coupling reaction.

  12. Synthesis of Isoiminosugars

    DEFF Research Database (Denmark)

    Hyldtoft, Lene; Godskesen, Michael Anders; Lundt, Inge

    1998-01-01

    A short synthesis of isoiminosugars have been developed. Bromolactones are diastereoselectively alkylated at C-2 followed by ring closure to the corresponding lactams. Reduction of these then gives isoiminosugars......A short synthesis of isoiminosugars have been developed. Bromolactones are diastereoselectively alkylated at C-2 followed by ring closure to the corresponding lactams. Reduction of these then gives isoiminosugars...

  13. Synthesis of oligonucleotide phosphorodithioates

    DEFF Research Database (Denmark)

    Beaton, G.; Brill, W. K D; Grandas, A.

    1991-01-01

    The synthesis of DNA containing sulfur at the two nonbonding internucleotide valencies is reported. Several different routes using either tervalent or pentavalent mononucleotide synthons are described.......The synthesis of DNA containing sulfur at the two nonbonding internucleotide valencies is reported. Several different routes using either tervalent or pentavalent mononucleotide synthons are described....

  14. Synthesis of zeolite membranes

    Institute of Scientific and Technical Information of China (English)

    JIANG Haiyang; ZHANG Baoquan; Y. S. Lin; LI Yongdan

    2004-01-01

    Zeolite membranes offer great application potentials in membrane separation and/or reaction due to their excellent separation performance and catalytic ability. Up to present, various synthesis methods of zeolite membranes have been developed, including embedded method,in-situ hydrothermal synthesis method, and secondary growth method etc. Compared with the in-situ hydrothermal synthesis method, the secondary growth method possesses a variety of advantages such as easier operation, higher controllability in crystal orientation, microstructure and film thickness, leading to much better reproducibility. This review provides a concise summary and analysis of various synthesis methods reported in the literature. In particular, the secondary growth method was discussed in detail in terms of crystal orientation, defects and crystal grain layers. Some critical issues were also highlighted, which were conducive to the improvement in the synthesis technology of zeolite membranes.

  15. VHDL for logic synthesis

    CERN Document Server

    Rushton, Andrew

    2011-01-01

    Many engineers encountering VHDL (very high speed integrated circuits hardware description language) for the first time can feel overwhelmed by it. This book bridges the gap between the VHDL language and the hardware that results from logic synthesis with clear organisation, progressing from the basics of combinational logic, types, and operators; through special structures such as tristate buses, register banks and memories, to advanced themes such as developing your own packages, writing test benches and using the full range of synthesis types. This third edition has been substantially rewritten to include the new VHDL-2008 features that enable synthesis of fixed-point and floating-point hardware. Extensively updated throughout to reflect modern logic synthesis usage, it also contains a complete case study to demonstrate the updated features. Features to this edition include: * a common VHDL subset which will work across a range of different synthesis systems, targeting a very wide range of technologies...

  16. 病毒感染因子在APOBEC3G抗病毒中的拮抗作用%Antagonistic Effect of Virion Infectivity Factor and APOBEC3G in the Intrinsic Antiretroviral Defense

    Institute of Scientific and Technical Information of China (English)

    王运华; 张耀洲

    2008-01-01

    病毒感染因子(virion infectivity factor, Vif)是人免疫缺陷病毒(human im_mu_n_o_de_fi_cien_cy virus, HIV)的6个辅助蛋白之一, 是病毒进行有效复制所必需的.由于Vif功能的复杂性以及对相应复合物体系的不了解, 一直以来, 对Vif的研究进展缓慢.直到2002年发现载脂蛋白B mRNA编辑酶催化多肽样蛋白3G (apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G, APOBEC3G)是存在于细胞内的一种天然抗病毒因子后, Vif的功能才被逐步阐明.APOBEC3G主要通过嘧啶脱氨基活性使HIV-1的负链DNA在逆转录过程中发生致死性超突变, 从而起到抗病毒作用.HIV-1基因编码Vif来拮抗APOBEC3G, 二者在宿主细胞内达到动态平衡.Vif通过介导APOBEC3G降解、减少在胞内的表达、阻碍其向病毒粒子的包装以及促使其装配成无活性的高分子质量复合体等多种途径起到中和作用.对Vif/APOBEC3G相互作用及其调节机制的进一步研究, 将为新型抗HIV-1病毒药物的研制与开发提供理论依据.

  17. APOBEC3G induces a hypermutation gradient: purifying selection at multiple steps during HIV-1 replication results in levels of G-to-A mutations that are high in DNA, intermediate in cellular viral RNA, and low in virion RNA

    Directory of Open Access Journals (Sweden)

    Pathak Vinay K

    2009-02-01

    Full Text Available Abstract Background Naturally occurring Vif variants that are unable to inhibit the host restriction factor APOBEC3G (A3G have been isolated from infected individuals. A3G can potentially induce G-to-A hypermutation in these viruses, and hypermutation could contribute to genetic variation in HIV-1 populations through recombination between hypermutant and wild-type genomes. Thus, hypermutation could contribute to the generation of immune escape and drug resistant variants, but the genetic contribution of hypermutation to the viral evolutionary potential is poorly understood. In addition, the mechanisms by which these viruses persist in the host despite the presence of A3G remain unknown. Results To address these questions, we generated a replication-competent HIV-1 Vif mutant in which the A3G-binding residues of Vif, Y40RHHY44, were substituted with five alanines. As expected, the mutant was severely defective in an A3G-expressing T cell line and exhibited a significant delay in replication kinetics. Analysis of viral DNA showed the expected high level of G-to-A hypermutation; however, we found substantially reduced levels of G-to-A hypermutation in intracellular viral RNA (cRNA, and the levels of G-to-A mutations in virion RNA (vRNA were even further reduced. The frequencies of hypermutation in DNA, cRNA, and vRNA were 0.73%, 0.12%, and 0.05% of the nucleotides sequenced, indicating a gradient of hypermutation. Additionally, genomes containing start codon mutations and early termination codons within gag were isolated from the vRNA. Conclusion These results suggest that sublethal levels of hypermutation coupled with purifying selection at multiple steps during the early phase of viral replication lead to the packaging of largely unmutated genomes, providing a mechanism by which mutant Vif variants can persist in infected individuals. The persistence of genomes containing mutated gag genes despite this selection pressure indicates that dual

  18. Asymmetric synthesis v.4

    CERN Document Server

    Morrison, James

    1984-01-01

    Asymmetric Synthesis, Volume 4: The Chiral Carbon Pool and Chiral Sulfur, Nitrogen, Phosphorus, and Silicon Centers describes the practical methods of obtaining chiral fragments. Divided into five chapters, this book specifically examines initial chiral transmission and extension. The opening chapter describes the so-called chiral carbon pool, the readily available chiral carbon fragments used as building blocks in synthesis. This chapter also provides a list of 375 chiral building blocks, along with their commercial sources, approximate prices, and methods of synthesis. Schemes involving

  19. Mechanochemical organic synthesis.

    Science.gov (United States)

    Wang, Guan-Wu

    2013-09-21

    Recently, mechanical milling using a mixer mill or planetary mill has been fruitfully utilized in organic synthesis under solvent-free conditions. This review article provides a comprehensive overview of various solvent-free mechanochemical organic reactions, including metal-mediated or -catalyzed reactions, condensation reactions, nucleophilic additions, cascade reactions, Diels-Alder reactions, oxidations, reductions, halogenation/aminohalogenation, etc. The ball milling technique has also been applied to the synthesis of calixarenes, rotaxanes and cage compounds, asymmetric synthesis as well as the transformation of biologically active compounds.

  20. Hydrothermal organic synthesis experiments

    Science.gov (United States)

    Shock, Everett L.

    1992-01-01

    Ways in which heat is useful in organic synthesis experiments are described, and experiments on the hydrothermal destruction and synthesis of organic compounds are discussed. It is pointed out that, if heat can overcome kinetic barriers to the formation of metastable states from reduced or oxidized starting materials, abiotic synthesis under hydrothermal conditions is a distinct possibility. However, carefully controlled experiments which replicate the descriptive variables of natural hydrothermal systems have not yet been conducted with the aim of testing the hypothesis of hydrothermal organic systems.

  1. Experimental Aspects of Synthesis

    CERN Document Server

    Ehlers, Rüdiger

    2011-01-01

    We discuss the problem of experimentally evaluating linear-time temporal logic (LTL) synthesis tools for reactive systems. We first survey previous such work for the currently publicly available synthesis tools, and then draw conclusions by deriving useful schemes for future such evaluations. In particular, we explain why previous tools have incompatible scopes and semantics and provide a framework that reduces the impact of this problem for future experimental comparisons of such tools. Furthermore, we discuss which difficulties the complex workflows that begin to appear in modern synthesis tools induce on experimental evaluations and give answers to the question how convincing such evaluations can still be performed in such a setting.

  2. Generalised Rabin(1) synthesis

    CERN Document Server

    Ehlers, Ruediger

    2010-01-01

    We present a novel method for the synthesis of finite state systems that is a generalisation of the generalised reactivity(1) synthesis approach by Piterman, Pnueli and Sa'ar. In particular, we describe an efficient method to synthesize systems from linear-time temporal logic specifications for which all assumptions and guarantees have a Rabin index of one. We show how to build a parity game with at most five colours that captures all solutions to the synthesis problem from such a specification. This parity game has a structure that is amenable to symbolic implementations. We furthermore show that the results obtained are in some sense tight, i.e., that there does not exist a similar synthesis method for assumptions and specifications of higher Rabin index, unless P=NP.

  3. Catalytic Synthesis Lactobionic Acid

    Directory of Open Access Journals (Sweden)

    V.G. Borodina

    2014-07-01

    Full Text Available Gold nanoparticles are obtained, characterized and deposited on the carrier. Conducted catalytic synthesis of lactobionic acid from lactose. Received lactobionic acid identify on the IR spectrum.

  4. Synthesis of Acetylhomoagmatine

    Directory of Open Access Journals (Sweden)

    Carmenza Duque

    2006-08-01

    Full Text Available Abstract: The first total synthesis of acetylhomoagmatine, a natural product isolated form the methanolic extracts from the sponge Cliona celata, is performed in four steps in a very high yield.

  5. Synthesis of Tacaribe virus polypeptides in an in vitro coupled transcription and translation system.

    Science.gov (United States)

    Boersma, D P; Compans, R W

    1985-04-01

    We have analyzed polypeptides synthesized in a coupled in vitro transcription and translation system in response to detergent-disrupted Tacaribe virus. Analysis of the major Tacaribe virus-specified product by two-dimensional polyacrylamide gel electrophoresis indicated that it had an isoelectric point similar to that of the Tacaribe nucleocapsid polypeptide N; however, the in vitro product had an approximate mol. wt. of 73 000, compared to a mol. wt. of 68 000 for the N protein. The 73 000 dalton product was found to yield proteolytic cleavage products with similar electrophoretic mobilities to those obtained from the virion P and N proteins. These results, as well as pulse-chase experiments in Tacaribe virus-infected cells, suggest that a 73 000 dalton polypeptide may be processed to yield the N polypeptide. The polypeptides synthesized in the coupled system depended on the amount and type of virus added; addition of purified Shark River (SR) virus, a member of the Patois group of bunyaviruses, resulted in synthesis of a polypeptide of mol. wt. 22 000 which corresponds to the SR nucleocapsid protein.

  6. Speech Compression and Synthesis

    Science.gov (United States)

    1980-10-01

    phonological rules combined with diphone improved the algorithms used by the phonetic synthesis prog?Im for gain normalization and time... phonetic vocoder, spectral template. i0^Th^TreprtTörc"u’d1sTuV^ork for the past two years on speech compression’and synthesis. Since there was an...from Block 19: speech recognition, pnoneme recogmtion. initial design for a phonetic recognition program. We also recorded ana partially labeled a

  7. Instrument Modeling and Synthesis

    Science.gov (United States)

    Horner, Andrew B.; Beauchamp, James W.

    During the 1970s and 1980s, before synthesizers based on direct sampling of musical sounds became popular, replicating musical instruments using frequency modulation (FM) or wavetable synthesis was one of the “holy grails” of music synthesis. Synthesizers such as the Yamaha DX7 allowed users great flexibility in mixing and matching sounds, but were notoriously difficult to coerce into producing sounds like those of a given instrument. Instrument design wizards practiced the mysteries of FM instrument design.

  8. Parallelizing quantum circuit synthesis

    OpenAIRE

    Di Matteo, Olivia; Mosca, Michele

    2016-01-01

    Quantum circuit synthesis is the process in which an arbitrary unitary operation is decomposed into a sequence of gates from a universal set, typically one which a quantum computer can implement both efficiently and fault-tolerantly. As physical implementations of quantum computers improve, the need is growing for tools which can effectively synthesize components of the circuits and algorithms they will run. Existing algorithms for exact, multi-qubit circuit synthesis scale exponentially in t...

  9. Detonation-synthesis nanodiamonds: synthesis, structure, properties and applications

    Energy Technology Data Exchange (ETDEWEB)

    Dolmatov, Valerii Yu [Federal State Unitary Enterprise Special Design-Technology Bureau (FSUE SDTB) ' ' Tekhnolog' ' at the St Petersburg State Institute of Technology (Technical University) (Russian Federation)

    2007-04-30

    The review outlines the theoretical foundations and industrial implementations of modern detonation synthesis of nanodiamonds and chemical purification of the nanodiamonds thus obtained. The structure, key properties and promising fields of application of detonation-synthesis nanodiamonds are considered.

  10. Behavioral synthesis of asynchronous circuits

    DEFF Research Database (Denmark)

    Nielsen, Sune Fallgaard

    2005-01-01

    This thesis presents a method for behavioral synthesis of asynchronous circuits, which aims at providing a synthesis flow which uses and tranfers methods from synchronous circuits to asynchronous circuits. We move the synchronous behavioral synthesis abstraction into the asynchronous handshake...... is idle. This reduces unnecessary switching activity in the individual functional units and therefore the energy consumption of the entire circuit. A collection of behavioral synthesis algorithms have been developed allowing the designer to perform time and power constrained design space exploration...

  11. Direct Dimethyl Ether Synthesis

    Institute of Scientific and Technical Information of China (English)

    Takashi Ogawa; Norio Inoue; Tutomu Shikada; Yotaro Ohno

    2003-01-01

    Dimethyl ether (DME) is a clean and economical alternative fuel which can be produced from natural gas through synthesis gas. The properties of DME are very similar to those of LP gas. DME can be used for various fields as a fuel such as power generation, transportation, home heating and cooking,etc. It contains no sulfur or nitrogen. It is not corrosive to any metal and not harmful to human body. An innovative process of direct synthesis of DME from synthesis gas has been developed. Newly developed catalyst in a slurry phase reactor gave a high conversion and high selectivity of DME production. One and half year pilot scale plant (5 tons per day) testing, which was supported by METI, had successfully finished with about 400 tons DME production.

  12. Synthesis of taurospongin A.

    Science.gov (United States)

    Wu, Boshen; Mallinger, Aurélie; Robertson, Jeremy

    2010-06-18

    Two new routes to the C(1-10) carboxylic acid core of taurospongin A are presented. In the first route, overall asymmetric hydration of a C(2)-C(3) alkene is achieved by Sharpless AD and selective deoxygenation at C(2); in the second route, the C(3) stereogenic center is set by Tietze asymmetric allylation. A short synthesis of the C(1'-25') fatty acid combines with the product from the first route to complete the total synthesis of taurospongin A.

  13. Reversible Logic Circuit Synthesis

    CERN Document Server

    Shende, V V; Markov, I L; Prasad, A K; Hayes, John P.; Markov, Igor L.; Prasad, Aditya K.; Shende, Vivek V.

    2002-01-01

    Reversible, or information-lossless, circuits have applications in digital signal processing, communication, computer graphics and cryptography. They are also a fundamental requirement for quantum computation. We investigate the synthesis of reversible circuits that employ a minimum number of gates and contain no redundant input-output line-pairs (temporary storage channels). We propose new constructions for reversible circuits composed of NOT, Controlled-NOT, and TOFFOLI gates (the CNT gate library) based on permutation theory. A new algorithm is given to synthesize optimal reversible circuits using an arbitrary gate library. We also describe much faster heuristic algorithms. We also pursue applications of the proposed techniques to the synthesis of quantum circuits.

  14. Synthesis of carbon nanotubes.

    Science.gov (United States)

    Awasthi, Kalpana; Srivastava, Anchal; Srivastava, O N

    2005-10-01

    Carbon nanotubes play a fundamental role in the rapidly developing field of nanoscience and nanotechnology because of their unique properties and high potential for applications. In this article, the different synthesis methods of carbon nanotubes (both multi-walled and single-walled) are reviewed. From the industrial point of view, the chemical vapor deposition method has shown advantages over laser vaporization and electric arc discharge methods. This article also presents recent work in the controlled synthesis of carbon nanotubes with ordered architectures. Special carbon nanotube configurations, such as nanocoils, nanohorns, bamboo-shaped and carbon cylinder made up from carbon nanotubes are also discussed.

  15. Supercritical Synthesis of Biodiesel

    Directory of Open Access Journals (Sweden)

    Michel Vaultier

    2012-07-01

    Full Text Available The synthesis of biodiesel fuel from lipids (vegetable oils and animal fats has gained in importance as a possible source of renewable non-fossil energy in an attempt to reduce our dependence on petroleum-based fuels. The catalytic processes commonly used for the production of biodiesel fuel present a series of limitations and drawbacks, among them the high energy consumption required for complex purification operations and undesirable side reactions. Supercritical fluid (SCF technologies offer an interesting alternative to conventional processes for preparing biodiesel. This review highlights the advances, advantages, drawbacks and new tendencies involved in the use of supercritical fluids (SCFs for biodiesel synthesis.

  16. Stereoselective Synthesis of (+)-Boronolide

    Institute of Scientific and Technical Information of China (English)

    HU,Shou-Gang; HU,Tai-Shan; WU,Yu-Lin

    2004-01-01

    @@ (+)-Boronolide (1) and its deacetylated products have attracted much attention of synthetic chemists due to their diverse biological properties as well as their structural complexities.[1] Many of these reported synthesis involved dehydrogenation of δ-lactone by using benzeneseleninic anhydride or ring-closing olefin metathesis (RCM) to introduce the requisite α,β-unsaturated δ-lactone in boronolide. Here, we report the synthesis of boronolide with diastereoselective propargylation of α-hydroxy aldehyde as the key step and D-gluconolactone as the starting material.

  17. An Approach to Interface Synthesis

    DEFF Research Database (Denmark)

    Madsen, Jan; Hald, Bjarne

    1995-01-01

    may contain the re-use of existing modules). The interface synthesis approach describes the basic transformations needed to transform the server interface description into an interface description on the client side of the communication medium. The synthesis approach is illustrated through a point......Presents a novel interface synthesis approach based on a one-sided interface description. Whereas most other approaches consider interface synthesis as optimizing a channel to existing client/server modules, we consider the interface synthesis as part of the client/server module synthesis (which......-to-point communication, but is applicable to synthesis of a multiple client/server environment. The interface description is based on a formalization of communication events....

  18. Synthesis of macrocyclic polyazomethines

    OpenAIRE

    Elizbarashvili,Elizbar; Matitaishvili,Tea; Topuria,Khatuna

    2007-01-01

    The synthesis of 20-membered macrocyclic polyazomethine dyes 3a and 3b from 4,4'-dihydroxybiphenyl-3,3'-dicarbaldehyde (2a) and 5,5'-diamino-4,4'-dihydroxybiphenyl-3,3'-dicarbaldehyde (2b) and macrocyclic polyazomethine pigments 4 and 5 from 3a is described.

  19. Synthesis beyond the molecule

    NARCIS (Netherlands)

    Reinhoudt, D.N.; Crego-Calama, M.

    2002-01-01

    Weak, noncovalent interactions between molecules control many biological functions. In chemistry, noncovalent interactions are now exploited for the synthesis in solution of large supramolecular aggregates. The aim of these syntheses is not only the creation of a particular structure, but also the i

  20. SYNTHESIS, CHARACTERIZATION AND ANTIBACTERIAL ...

    African Journals Online (AJOL)

    B. S. Chandravanshi

    conductance measurements, elemental analysis, infrared, UV/Vis, nuclear ... antipyretic properties [1, 2] and also used in the design and development of ... All chemicals used for the preparation of the complexes were of analytical ...... complexes also disturb the respiration process of the cell and thus block the synthesis of.

  1. Interval-based Synthesis

    Directory of Open Access Journals (Sweden)

    Angelo Montanari

    2014-08-01

    Full Text Available We introduce the synthesis problem for Halpern and Shoham's modal logic of intervals extended with an equivalence relation over time points, abbreviated HSeq. In analogy to the case of monadic second-order logic of one successor, the considered synthesis problem receives as input an HSeq formula phi and a finite set Sigma of propositional variables and temporal requests, and it establishes whether or not, for all possible evaluations of elements in Sigma in every interval structure, there exists an evaluation of the remaining propositional variables and temporal requests such that the resulting structure is a model for phi. We focus our attention on decidability of the synthesis problem for some meaningful fragments of HSeq, whose modalities are drawn from the set A (meets, Abar (met by, B (begins, Bbar (begun by, interpreted over finite linear orders and natural numbers. We prove that the fragment ABBbareq is decidable (non-primitive recursive hard, while the fragment AAbarBBbar turns out to be undecidable. In addition, we show that even the synthesis problem for ABBbar becomes undecidable if we replace finite linear orders by natural numbers.

  2. Enzymatic synthesis of vanillin

    NARCIS (Netherlands)

    van den Heuvel, RHH; Fraaije, MW; Laane, C; van Berkel, WJH; Heuvel, Robert H.H. van den; Berkel, Willem J.H. van

    2001-01-01

    Due to increasing interest in natural vanillin, two enzymatic routes for the synthesis of vanillin were developed. The flavoprotein vanillyl alcohol oxidase (VAO) acts on a wide range of phenolic compounds and converts both creosol and vanillylamine to vanillin with high yield. The VAO-mediated conv

  3. Sizing up surfactant synthesis.

    Science.gov (United States)

    Han, SeungHye; Mallampalli, Rama K

    2014-08-01

    Phosphatidylcholine is generated through de novo synthesis and remodeling involving a lysophospholipid. In this issue of Cell Metabolism, research from the Shimizu lab (Harayama et al., 2014) demonstrates the highly selective enzymatic behavior of lysophospholipid acyltransferases. The authors present an enzymatic model for phosphatidylcholine molecular species diversification that impacts surfactant formation.

  4. Total synthesis of aquatolide

    NARCIS (Netherlands)

    Saya, J.M.; Vos, K.; Klein Nijenhuis, R.A.; van Maarseveen, J.H.; Ingemann, S.; Hiemstra, H.

    2015-01-01

    A total synthesis of the sesquiterpene lactone aquatolide has been accomplished. The central step is an intramolecular [2 + 2]-photocycloaddition of an allene onto an alpha,beta-unsaturated delta-lactone. Other key steps are an intramolecular Horner-Wadsworth-Emmons reaction to close the lactone and

  5. The Synthesis of Glycoglycerolipids

    Institute of Scientific and Technical Information of China (English)

    Chun Xia LI; Ying Xia LI; Ling Bo YU; Hua ZHANG; Shi Dong CHU; Hua Shi GUAN

    2003-01-01

    A convenient synthetic route was developed for the synthesis of the novel glycolipids: 1, 2-di-O-acyl-3-O-(2'-acylamide-2'-deoxy-α-D-glucopyranosyl)-sn-glycerols. 10 new compounds of glycolipids with different acyl groups were obtained.

  6. Total Synthesis of Naloxone

    Institute of Scientific and Technical Information of China (English)

    HU Wen-Xiang; WANG Jian-Ying; XU Ming

    2003-01-01

    @@ Naloxone (1) is one of the 14-hydroxyl substituted opium antagonists which are valuable medications for treat ment of opiate abuse, opiate overdose, and alcohol addiction. Here, the total synthesis of naloxone was described. We selected 2,6-dihydroxynaphalene (2) as the starting material.

  7. Distributed Priority Synthesis

    Directory of Open Access Journals (Sweden)

    Harald Ruess

    2012-11-01

    Full Text Available Given a set of interacting components with non-deterministic variable update and given safety requirements, the goal of priority synthesis is to restrict, by means of priorities, the set of possible interactions in such a way as to guarantee the given safety conditions for all possible runs. In distributed priority synthesis we are interested in obtaining local sets of priorities, which are deployed in terms of local component controllers sharing intended next moves between components in local neighborhoods only. These possible communication paths between local controllers are specified by means of a communication architecture. We formally define the problem of distributed priority synthesis in terms of a multi-player safety game between players for (angelically selecting the next transition of the components and an environment for (demonically updating uncontrollable variables. We analyze the complexity of the problem, and propose several optimizations including a solution-space exploration based on a diagnosis method using a nested extension of the usual attractor computation in games together with a reduction to corresponding SAT problems. When diagnosis fails, the method proposes potential candidates to guide the exploration. These optimized algorithms for solving distributed priority synthesis problems have been integrated into the VissBIP framework. An experimental validation of this implementation is performed using a range of case studies including scheduling in multicore processors and modular robotics.

  8. Regioselective Synthesis of Indanones

    NARCIS (Netherlands)

    van Leeuwen, Thomas; Neubauer, Thomas M.; Feringa, Ben L.

    2014-01-01

    The degree of hydrolysis of polyphosphoric acid (PPA) has a crucial effect on the regioselectivity of the PPA-mediated synthesis of indanones. It was found that the regioselectivity can be switched by employing PPA with either a high or low content of P2O5. This methodology was used for the regiosel

  9. SHORT COMMUNICATION SYNTHESIS AND ...

    African Journals Online (AJOL)

    a

    The synthesis and characterization of zinc(II) and copper(II) complexes of ... fairly good catalytic activity for the reduction of molecular oxygen. In this ... washed with 150 mL methanol, followed by 100 mL acetone and finally 50 mL diethyl ether.

  10. Industrial scale gene synthesis.

    Science.gov (United States)

    Notka, Frank; Liss, Michael; Wagner, Ralf

    2011-01-01

    The most recent developments in the area of deep DNA sequencing and downstream quantitative and functional analysis are rapidly adding a new dimension to understanding biochemical pathways and metabolic interdependencies. These increasing insights pave the way to designing new strategies that address public needs, including environmental applications and therapeutic inventions, or novel cell factories for sustainable and reconcilable energy or chemicals sources. Adding yet another level is building upon nonnaturally occurring networks and pathways. Recent developments in synthetic biology have created economic and reliable options for designing and synthesizing genes, operons, and eventually complete genomes. Meanwhile, high-throughput design and synthesis of extremely comprehensive DNA sequences have evolved into an enabling technology already indispensable in various life science sectors today. Here, we describe the industrial perspective of modern gene synthesis and its relationship with synthetic biology. Gene synthesis contributed significantly to the emergence of synthetic biology by not only providing the genetic material in high quality and quantity but also enabling its assembly, according to engineering design principles, in a standardized format. Synthetic biology on the other hand, added the need for assembling complex circuits and large complexes, thus fostering the development of appropriate methods and expanding the scope of applications. Synthetic biology has also stimulated interdisciplinary collaboration as well as integration of the broader public by addressing socioeconomic, philosophical, ethical, political, and legal opportunities and concerns. The demand-driven technological achievements of gene synthesis and the implemented processes are exemplified by an industrial setting of large-scale gene synthesis, describing production from order to delivery.

  11. Benzoylurea Chitin Synthesis Inhibitors.

    Science.gov (United States)

    Sun, Ranfeng; Liu, Chunjuan; Zhang, Hao; Wang, Qingmin

    2015-08-12

    Benzoylurea chitin synthesis inhibitors are widely used in integrated pest management (IPM) and insecticide resistance management (IRM) programs due to their low toxicity to mammals and predatory insects. In the past decades, a large number of benzoylurea derivatives have been synthesized, and 15 benzoylurea chitin synthesis inhibitors have been commercialized. This review focuses on the history of commercial benzolyphenylureas (BPUs), synthetic methods, structure-activity relationships (SAR), action mechanism research, environmental behaviors, and ecotoxicology. Furthermore, their disadvantages of high risk to aquatic invertebrates and crustaceans are pointed out. Finally, we propose that the para-substituents at anilide of benzoylphenylureas should be the functional groups, and bipartite model BPU analogues are discussed in an attempt to provide new insight for future development of BPUs.

  12. Prebiotic synthesis of histidine

    Science.gov (United States)

    Shen, C.; Yang, L.; Miller, S. L.; Oro, J.

    1990-01-01

    The prebiotic formation of histidine (His) has been accomplished experimentally by the reaction of erythrose with formamidine followed by a Strecker synthesis. In the first step of this reaction sequence, the formation of imidazole-4-acetaldehyde took place by the condensation of erythrose and formamidine, two compounds that are known to be formed under prebiotic conditions. In a second step, the imidazole-4-acetaldehyde was converted to His, without isolation of the reaction products by adding HCN and ammonia to the reaction mixture. LC, HPLC, thermospray liquid chromatography-mass spectrometry, and tandem mass spectrometry were used to identify the product, which was obtained in a yield of 3.5% based on the ratio of His/erythrose. This is a new chemical synthesis of one of the basic amino acids which had not been synthesized prebiotically until now.

  13. Toleration, Synthesis or Replacement?

    DEFF Research Database (Denmark)

    Holtermann, Jakob v. H.; Madsen, Mikael Rask

    2016-01-01

    to have considerable problems keeping a clear focus on the key question: What are the implications of this empirical turn in terms of philosophy of legal science, of the social understanding of IL, and, not least, of the place of doctrinal scholarship after the alleged Wende? What is needed, we argue......, in order to answer is not yet another partisan suggestion, but rather an attempt at making intelligible both the oppositions and the possibilities of synthesis between normative and empirical approaches to law. Based on our assessment and rational reconstruction of current arguments and positions, we...... therefore outline a taxonomy consisting of the following three basic, ideal-types in terms of the epistemological understanding of the interface of law and empirical studies: toleration, synthesis and replacement. This tripartite model proves useful with a view to teasing out and better articulating...

  14. Control of protein synthesis in herpesvirus-infected cells: analysis of the polypeptides induced by wild type and sixteen temperature-sensitive mutants of HSV strain 17.

    Science.gov (United States)

    Marsden, H S; Crombie, I K; Subak-Sharpe, J H

    1976-06-01

    The polypeptides induced in cells infected with a Glasgow isolate of HSV-I (17 syn+) have been characterized by SDS polyacrylamide gel electrophoresis. Study of the kinetics of synthesis in three cell lines has detected a total of 52 polypeptides, 33 of which can be identified in polypeptide profiles of purified virions. These include six low mol. wt. polypeptides that have not been previously reported. Several polypeptides were labelled with glucosamine in infected BHK cells. The different polypeptide patterns obtained at permissive (31 degrees C) and nonpermissive (38 degrees C) temperature in cells infected with 16 temperature-sensitive (ts) mutants are reported. The effect of multiplicity of infection (m.o.i.) on the polypeptide profile has been examined for two of the DNA -ve mutants: below ten, the profile varied with the m.o.i. whereas above ten it was constant. All mutants were therefore examined at an m.o.i. of approx. 20. Mutants from the same complementation group showed very similar profiles. A number of general conclusions concerning control of protein synthesis in HSV infected cells can be made: (I) As most of the 16 ts mutants affected the synthesis of several or many polypeptides it follows that a large proportion of genome specifies controlling functions. (2) The high frequency with which some polypeptides were affected suggests they are at or near the terminus of biosynthetic pathways which are under multiple control. (3) Conversely, some polypeptides were affected with a low frequency suggesting that their synthesis is not dependent on the expression of many virus functions. (4) Several individual ts mutations lead to the synthesis of increased amounts of different large polypeptides. (5) Analysis of every band detectably affected by at least one ts mutation has disclosed nine classes of dependence relationship between polypeptide synthesis and the DNA phenotype of the mutants, illustrating that this relationship is complex and different for

  15. The total synthesis of psymberin.

    Science.gov (United States)

    Huang, Xianhai; Shao, Ning; Palani, Anandan; Aslanian, Robert; Buevich, Alexei

    2007-06-21

    The total synthesis of a new member of the pederin family of natural products, psymberin 1, was accomplished. Using a recently reported novel and efficient PhI(OAc)2 mediated oxidative entry to 2-(N-acylaminal)-substituted tetrahydropyrans as the key step, this total synthesis was executed in a convergent and efficient manner. The longest linear sequence of this synthesis was 22 steps starting from known 6.

  16. PROTEIN SYNTHESIS GAME

    Directory of Open Access Journals (Sweden)

    J.C.Q. Carvalho

    2004-05-01

    Full Text Available The theoretical explanation of biological concepts, associated with the use of teaching games andmodels, intensify the comprehension and increase students interest, stimulating them to participateactively on the teaching-learning process. The sta of dissemination from Centro de BiotecnologiaMolecular Estrutural (CBME, in partnership with the Centro de Divulgac~ao Cientca e Cultural(CDCC, presents, in this work, a new educational resource denoted: Protein Synthesis Game. Theapproach of the game involves the cytological aspects of protein synthesis, directed to high schoolstudents. Students are presented to day-by-day facts related to the function of a given protein in thehuman body. Such task leads players to the goal of solving out a problem through synthesizing aspecied protein. The game comprises: (1 a board illustrated with the transversal section of animalcell, with its main structures and organelles and sequences of hypothetical genes; (2 cards with thedescription of steps and other structures required for protein synthesis in eukaryotic cells; (3 piecesrepresenting nucleotides, polynucleotides, ribosome, amino acids, and polypeptide chains. In order toplay the game, students take cards that sequentially permit them to acquire the necessary pieces forproduction of the protein described in each objective. Players must move the pieces on the board andsimulate the steps of protein synthesis. The dynamic of the game allows students to easily comprehendprocesses of transcription and translation. This game was presented to dierent groups of high schoolteachers and students. Their judgments have been heard and indicated points to be improved, whichhelped us with the game development. Furthermore, the opinions colleted were always favorable forthe application of this game as a teaching resource in classrooms.

  17. Phase contrast image synthesis

    DEFF Research Database (Denmark)

    Glückstad, J.

    1996-01-01

    A new method is presented for synthesizing arbitrary intensity patterns based on phase contrast imaging. The concept is grounded on an extension of the Zernike phase contrast method into the domain of full range [0; 2 pi] phase modulation. By controlling the average value of the input phase...... function and by choosing appropriate phase retardation at the phase contrast filter, a pure phase to intensity imaging is accomplished. The method presented is also directly applicable in dark field image synthesis....

  18. Total synthesis of (+/-)-cytisine.

    Science.gov (United States)

    O'Neill, B T; Yohannes, D; Bundesmann, M W; Arnold, E P

    2000-12-28

    [reaction:see text] The nicotine partial agonist cytisine was prepared in five steps featuring an "in situ" Stille or Suzuki biaryl pyridine coupling. Differentiation of the pyridyl rings was accomplished via selective benzylation and then reduction of a pyridinium ring. The penultimate diazabicyclo[3.3.1]nonane intermediate was obtained with high diastereoselectivity. A similar sequence has been employed for the synthesis of novel derivative 9-methoxycytisine.

  19. Total synthesis of teixobactin

    Science.gov (United States)

    Jin, Kang; Sam, Iek Hou; Po, Kathy Hiu Laam; Lin, Du'an; Ghazvini Zadeh, Ebrahim H.; Chen, Sheng; Yuan, Yu; Li, Xuechen

    2016-08-01

    To cope with the global bacterial multidrug resistance, scientific communities have devoted significant efforts to develop novel antibiotics, particularly those with new modes of actions. Teixobactin, recently isolated from uncultured bacteria, is considered as a promising first-in-class drug candidate for clinical development. Herein, we report its total synthesis by a highly convergent Ser ligation approach and this strategy allows us to prepare several analogues of the natural product.

  20. Microwave Multicomponent Synthesis

    Directory of Open Access Journals (Sweden)

    Helmut M. Hügel

    2009-12-01

    Full Text Available In the manner that very important research is often performed by multidisciplinary research teams, the applications of multicomponent reactions involving the combination of multiple starting materials with different functional groups leading to the higher efficiency and environmentally friendly construction of multifunctional/complex target molecules is growing in importance. This review will explore the advances and advantages in microwave multicomponent synthesis (MMS that have been achieved over the last five years.

  1. Synthesis of phenoxyamines

    Energy Technology Data Exchange (ETDEWEB)

    Castellino, A.J.; Rapoport, H.

    1984-04-20

    Treatment of phenols with 2,4-dinitrophenoxyamine leads to the synthesis of phenoxyamines through an amine exchange reaction. Yields for this reaction are sensitive to the pK/sub a/ of the phenol in a manner explainable in terms of a competing bimolecular decomposition reaction involving the 2,4-dinitrophenoxyamine. By use of an appropriately substituted phenol, this phenomenon can be exploited to give high yields of phenoxyamines having oxygenated substitution patterns that were unattainable by previous methods.

  2. Gold Nanoparticle Microwave Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Kelsie E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Christian, Jonathan H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coopersmith, Kaitlin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Murph, Simona H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  3. Bayesian Face Sketch Synthesis.

    Science.gov (United States)

    Wang, Nannan; Gao, Xinbo; Sun, Leiyu; Li, Jie

    2017-03-01

    Exemplar-based face sketch synthesis has been widely applied to both digital entertainment and law enforcement. In this paper, we propose a Bayesian framework for face sketch synthesis, which provides a systematic interpretation for understanding the common properties and intrinsic difference in different methods from the perspective of probabilistic graphical models. The proposed Bayesian framework consists of two parts: the neighbor selection model and the weight computation model. Within the proposed framework, we further propose a Bayesian face sketch synthesis method. The essential rationale behind the proposed Bayesian method is that we take the spatial neighboring constraint between adjacent image patches into consideration for both aforementioned models, while the state-of-the-art methods neglect the constraint either in the neighbor selection model or in the weight computation model. Extensive experiments on the Chinese University of Hong Kong face sketch database demonstrate that the proposed Bayesian method could achieve superior performance compared with the state-of-the-art methods in terms of both subjective perceptions and objective evaluations.

  4. Chemistry of Ammonothermal Synthesis

    Directory of Open Access Journals (Sweden)

    Theresia M. M. Richter

    2014-02-01

    Full Text Available Ammonothermal synthesis is a method for synthesis and crystal growth suitable for a large range of chemically different materials, such as nitrides (e.g., GaN, AlN, amides (e.g., LiNH2, Zn(NH22, imides (e.g., Th(NH2, ammoniates (e.g., Ga(NH33F3, [Al(NH36]I3 · NH3 and non-nitrogen compounds like hydroxides, hydrogen sulfides and polychalcogenides (e.g., NaOH, LiHS, CaS, Cs2Te5. In particular, large scale production of high quality crystals is possible, due to comparatively simple scalability of the experimental set-up. The ammonothermal method is defined as employing a heterogeneous reaction in ammonia as one homogenous fluid close to or in supercritical state. Three types of milieus may be applied during ammonothermal synthesis: ammonobasic, ammononeutral or ammonoacidic, evoked by the used starting materials and mineralizers, strongly influencing the obtained products. There is little known about the dissolution and materials transport processes or the deposition mechanisms during ammonothermal crystal growth. However, the initial results indicate the possible nature of different intermediate species present in the respective milieus.

  5. Gold Nanoparticle Microwave Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Kelsie E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Christian, Jonathan H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coopersmith, Kaitlin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Murph, Simona H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, a reduction in reaction time from 10 minutes to 1 minute, maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  6. Green Chemistry for Chemical Synthesis

    National Research Council Canada - National Science Library

    Chao-Jun Li; Barry M. Trost

    2008-01-01

    Green chemistry for chemical synthesis addresses our future challenges in working with chemical processes and products by inventing novel reactions that can maximize the desired products and minimize...

  7. Hydrothermal organic synthesis experiments

    Science.gov (United States)

    Shock, Everett L.

    1992-01-01

    The serious scientific debate about spontaneous generation which raged for centuries reached a climax in the nineteenth century with the work of Spallanzani, Schwann, Tyndall, and Pasteur. These investigators demonstrated that spontaneous generation from dead organic matter does not occur. Although no aspects of these experiments addressed the issue of whether organic compounds could be synthesized abiotically, the impact of the experiments was great enough to cause many investigators to assume that life and its organic compounds were somehow fundamentally different than inorganic compounds. Meanwhile, other nineteenth-century investigators were showing that organic compounds could indeed be synthesized from inorganic compounds. In 1828 Friedrich Wohler synthesized urea in an attempt to form ammonium cyanate by heating a solution containing ammonia and cyanic acid. This experiment is generally recognized to be the first to bridge the artificial gap between organic and inorganic chemistry, but it also showed the usefulness of heat in organic synthesis. Not only does an increase in temperature enhance the rate of urea synthesis, but Walker and Hambly showed that equilibrium between urea and ammonium cyanate was attainable and reversible at 100 C. Wohler's synthesis of urea, and subsequent syntheses of organic compounds from inorganic compounds over the next several decades dealt serious blows to the 'vital force' concept which held that: (1) organic compounds owe their formation to the action of a special force in living organisms; and (2) forces which determine the behavior of inorganic compounds play no part in living systems. Nevertheless, such progress was overshadowed by Pasteur's refutation of spontaneous generation which nearly extinguished experimental investigations into the origins of life for several decades. Vitalism was dealt a deadly blow in the 1950's with Miller's famous spark-discharge experiments which were undertaken in the framework of the Oparin

  8. Total Synthesis of Bryostatin 9

    OpenAIRE

    Wender, Paul A.; Schrier, Adam J.

    2011-01-01

    The total synthesis of bryostatin 9 was accomplished using a uniquely step economical and convergent Prins-driven macrocyclization strategy. At 25 linear and 42 total steps, this is currently the most concise and convergent (5 steps post fragment coupling) synthesis of a potent bryostatin.

  9. Total synthesis of bryostatin 9.

    Science.gov (United States)

    Wender, Paul A; Schrier, Adam J

    2011-06-22

    The total synthesis of bryostatin 9 was accomplished using a uniquely step-economical and convergent Prins-driven macrocyclization strategy. At 25 linear and 42 total steps, this is currently the most concise and convergent synthesis of a potent bryostatin.

  10. SYNTHESIS OF MYCOPHENOLIC ACID (MPA)

    DEFF Research Database (Denmark)

    2008-01-01

    The present invention relates to novel tools for improving MPA production. In particular, the present invention relates tofungal enzymes that are specific for MPA synthesis.......The present invention relates to novel tools for improving MPA production. In particular, the present invention relates tofungal enzymes that are specific for MPA synthesis....

  11. Memory-based logic synthesis

    CERN Document Server

    Sasao, Tsutomu

    2011-01-01

    This book describes the synthesis of logic functions using memories. It is useful to design field programmable gate arrays (FPGAs) that contain both small-scale memories, called look-up tables (LUTs), and medium-scale memories, called embedded memories. This is a valuable reference for both FPGA system designers and CAD tool developers, concerned with logic synthesis for FPGAs.

  12. Stepwise decomposition in controlpath synthesis

    NARCIS (Netherlands)

    Berg, ten A.J.W.M.

    1990-01-01

    A method is presented for the synthesis of the microarchitecture of controlpaths. This method is called stepwise decomposition. It focuses primarily on controlpaths of instruction set processors, however it is also applicable for more general Finite State Machine synthesis. Many of the current contr

  13. Chemical synthesis on SU-8

    DEFF Research Database (Denmark)

    Qvortrup, Katrine; Taveras, Kennedy; Thastrup, Ole

    2011-01-01

    In this paper we describe a highly effective surface modification of SU-8 microparticles, the attachment of appropriate linkers for solid-supported synthesis, and the successful chemical modification of these particles via controlled multi-step organic synthesis leading to molecules attached...

  14. Stepwise decomposition in controlpath synthesis

    NARCIS (Netherlands)

    ten Berg, A.J.W.M.; ten Berg, A.J.W.M.

    1990-01-01

    A method is presented for the synthesis of the microarchitecture of controlpaths. This method is called stepwise decomposition. It focuses primarily on controlpaths of instruction set processors, however it is also applicable for more general Finite State Machine synthesis. Many of the current contr

  15. Chemical synthesis on SU-8.

    Science.gov (United States)

    Qvortrup, Katrine; Taveras, Kennedy M; Thastrup, Ole; Nielsen, Thomas E

    2011-01-28

    In this paper we describe a highly effective surface modification of SU-8 microparticles, the attachment of appropriate linkers for solid-supported synthesis, and the successful chemical modification of these particles via controlled multi-step organic synthesis leading to molecules attached in an unambiguous manner to the support surface.

  16. On the synthesis of plasmalogens

    NARCIS (Netherlands)

    Slotboom, A.J.; Haas, Gerard H. de; Deenen, L.L.M. van

    1967-01-01

    The chemical synthesis is described of (rac)-trans-1-(n-hexadec-1′-enyloxy)-2-oleoylglycerol-3-phosphorylcholine (plasmalogen). This synthesis made use of a specific degradation of (rac)-trans-1-(n-hexadec-1′-enyloxy)-2,3-dioleoyl glycerol with pancreatic lipase (EC 3.1.1.3). This enzyme, which cata

  17. Synthesis of reduced collagen crosslinks

    NARCIS (Netherlands)

    Nieuwendijk, A.M.C.H. van den; Benningshof, J.C.J.; Wegmann, V.; Bank, R.A.; Koppele, J.M. te; Brussee, J.; Gen, A. van der

    1999-01-01

    A new synthetic route to reduced collagen crosslinks (LNL and HLNL) is described in this report. It enables an enantioselective synthesis of LNL. HLNL was obtained as a mixture of two diastereoisomers. This method also provides the possibility to introduce radio-labels during the synthesis.

  18. A novel synthesis of hemispherands

    NARCIS (Netherlands)

    Ostaszewski, Ryszard; Verboom, Willem; Reinhoudt, David N.

    1992-01-01

    A novel, flexible synthesis of hemispherands {2,5,8-trioxa[9](3,3″) m-terphenylophanes 5a-d} with different central aromatic groups is described. The key step comprises the introduction of the central aromatic ring in the last step of the synthesis via a Suzuki cross-coupling reaction using palladiu

  19. Synthesis of reduced collagen crosslinks

    NARCIS (Netherlands)

    Nieuwendijk, A.M.C.H. van den; Benningshof, J.C.J.; Wegmann, V.; Bank, R.A.; Koppele, J.M. te; Brussee, J.; Gen, A. van der

    1999-01-01

    A new synthetic route to reduced collagen crosslinks (LNL and HLNL) is described in this report. It enables an enantioselective synthesis of LNL. HLNL was obtained as a mixture of two diastereoisomers. This method also provides the possibility to introduce radio-labels during the synthesis.

  20. Radiochemical synthesis of etomoxir

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Hafiz G. [Institute of Nuclear Medicine and Oncology (INMOL), New Campus Road, Lahore (Pakistan); Yunus, M. [University of the Punjab, New Campus Road, Lahore (Pakistan); Feinendegen, Ludwig E., E-mail: feinendegen@gmx.ne [Department of Nuclear Medicine, Heinrich-Heine University Duesseldorf, Wannental 45, 88131 Lindau (Germany)

    2011-02-15

    Sodium 2-{l_brace}6-(4-chlorophenoxy)hexyl{r_brace}oxirane-2-carboxylate (Etomoxir) inhibits transport of fatty acids via the carnitine shuttle into mitochondria of muscle cells and prevents long chain fatty acids from providing energy through {beta}-oxidation especially for muscle contraction. The objective of this synthesis is to develop a method for radioiodination of Etomoxir in order to explore its potential in diagnostic metabolic studies and molecular imaging. Thus, a method is described for the radiochemical synthesis and purification of ethyl 2-{l_brace}6-(4-[{sup 131}I]iodophenoxy)hexyl{r_brace}oxirane-2-carboxylate (3) and 2-{l_brace}6-(4-[{sup 131}I]iodo-phenoxy)hexyl{r_brace}oxirane-2-carboxylic acid (4). For the synthesis of these new agents, ethyl 2-{l_brace}6-(4-bromophenoxy)hexyl{r_brace}oxirane-2-carboxylate (1) and 2-{l_brace}6-(4-bromophenoxy)hexyl{r_brace}oxirane-2-carboxylic acid (2) were refluxed with [{sup 131}I]NaI in the presence of anhydrous acetone at a temperature of 80 {sup o}C and 90 {sup o}C for a period of 3-4 hours, respectively. The method of radiolabeling, based on the nucleophilic exchange reaction, resulted in a radiochemical yield of 43% and 67% for compounds 3 and 4, respectively. This paper reports on the labeling of etomoxir with radioiodine as {sup 124}I labeled etomoxir may be of great importance in molecular imaging.

  1. Asymmetric synthesis of (-)-adaline.

    Science.gov (United States)

    Itoh, Toshimasa; Yamazaki, Naoki; Kibayashi, Chihiro

    2002-07-25

    [reaction: see text] An enantioselective total synthesis of (-)-adaline has been achieved starting from a chiral 6,6-disubstituted piperidone derivative previously prepared by diastereoselective allylation of a chiral tricyclic N-acyl-N,O-acetal. The key steps include lithium ion-activated SN2-type alkynylation of the tricyclic N,O-acetal leading to exclusive formation of the (6S)-ethynylpiperidine and ring-closing olefin metathesis of the (2R,6S)-cis-2,6-dialkenylpiperidine for constructing the bridged azabicyclononane.

  2. Synthesis of plant arabinogalactans

    Institute of Scientific and Technical Information of China (English)

    Fanzuo KONG

    2009-01-01

    Plant arabinogalactans consisting of a β-(1→6)-linked D-galactopyranosyl oligosaccharide back-synthesized based on the 1,2-anhydro galactopyranose technique, orthogonal (methoxydimethyl)methyl (MIP) and (2-naphthyl)methyl (NAP) protection strategy, and selective acylation or glycosylation method. The third method is the most simple and effective and it is also used for the synthesis of arabinogalactans composed of a β-(1→6)-linked D-galactopyranosyl oligosaccharide back-bone with α-(→3)-L-arabinofuranosyl branches.

  3. [New synthesis empathogenic agents].

    Science.gov (United States)

    Velea, D; Hautefeuille, M; Vazeille, G; Lantran-Davoux, C

    1999-01-01

    The use of synthesis drugs is the object of numerous written articles and TV programs in the last, decade. These synthesis drugs or "designer drugs", are well known for their ability to enhance, reinforce or appease social difficulties and relationships. In the research for empathetic and entactogenic relations one discover an obvious lack of communication and "warmth" in personal or professional relationship. An image of chemical "well being" has become a frequent stereotype of a society with an atrophying of performance and values while supposedly dedicating itself to individual performance. The youths are the first victims of these new drugs, the economical and social environment are the main reinforcing factors of this behaviour. The main characteristic of these drugs, is the non-recognition of their danger, some users go so far as to describe this category of substances as "drugs which are not drugs". As a characteristic, the use of a these synthesis drugs is almost recreative, during the week-end and holiday. The drug addiction is different than that of opiates or cocaine. One can observe some cases of real dependence--corresponding to the DSW IV criterion--when the personality of the users is the main characteristic (narcissic failure, immature personality, family and school problems). Many adverse effects--hypertension, kidney failure, psychoses--were declared. The mass-media has presented many articles concerning Ecstasy (MDMA). This is the most used drug during the rave parties. Its adverse effects are well known and proven. The authors would like to present other more recent synthesis drugs, also known as "analogs". These drugs, a kind of mixture between amphetamine-like (MDMA, MBDB, MDA) and misused medicines (ketamine, gamma OH, atropine) represent a real danger. GHB, 2 CB, HMB, are some of these recent substances. The possibility to procure them on the Web, or to produce them by oneself, add to their danger because of the lack of controls on toxicity

  4. Learning via Query Synthesis

    KAUST Repository

    Alabdulmohsin, Ibrahim Mansour

    2017-05-07

    Active learning is a subfield of machine learning that has been successfully used in many applications. One of the main branches of active learning is query synthe- sis, where the learning agent constructs artificial queries from scratch in order to reveal sensitive information about the underlying decision boundary. It has found applications in areas, such as adversarial reverse engineering, automated science, and computational chemistry. Nevertheless, the existing literature on membership query synthesis has, generally, focused on finite concept classes or toy problems, with a limited extension to real-world applications. In this thesis, I develop two spectral algorithms for learning halfspaces via query synthesis. The first algorithm is a maximum-determinant convex optimization method while the second algorithm is a Markovian method that relies on Khachiyan’s classical update formulas for solving linear programs. The general theme of these methods is to construct an ellipsoidal approximation of the version space and to synthesize queries, afterward, via spectral decomposition. Moreover, I also describe how these algorithms can be extended to other settings as well, such as pool-based active learning. Having demonstrated that halfspaces can be learned quite efficiently via query synthesis, the second part of this thesis proposes strategies for mitigating the risk of reverse engineering in adversarial environments. One approach that can be used to render query synthesis algorithms ineffective is to implement a randomized response. In this thesis, I propose a semidefinite program (SDP) for learning a distribution of classifiers, subject to the constraint that any individual classifier picked at random from this distributions provides reliable predictions with a high probability. This algorithm is, then, justified both theoretically and empirically. A second approach is to use a non-parametric classification method, such as similarity-based classification. In this

  5. Microemulsion Synthesis of Nanoparticles

    Directory of Open Access Journals (Sweden)

    Gotić, M.

    2013-11-01

    Full Text Available Nanoparticles and nanomaterials have wide applications in electronics, physics, material design, being also utilized as sensors, catalysts, and more and more in biomedicine. Microemulsions are an exceptionally suitable medium for the synthesis of nanoparticles due to their thermodynamical stability, great solubility of both polar and nonpolar components, as well as their ability to control the size, dispersity and shape of the particles. This review presents microemulsion techniques for the synthesis of inorganic nanoparticles. It takes place in water-in-oil microemulsions by mixing one microemulsion with a cationic precursor, and the other with a precipitating or reducing agent, or by direct addition of reducing agents or gas (O2, NH3 ili CO2 into microemul sion (Fig. 1. Metal nanoparticles are used as catalysts, sensors, ferrofluids etc. They are produced by reducing the metal cation with a suitable reducing agent. In a similar way, one can prepare nanoparticles of alloys from the metal salts, provided that the metals are mutually soluble. The microemulsion technique is also suitable for depositing nanoparticles onto various surfaces. Highly active catalysts made from nanoparticles of Pt, Pd, Rh and other noble metals may be obtained in this way. Metal oxides and hydroxides may be prepared by hydrolysis or precipitation in the water core of microemulsion. Precipitation can be initiated by adding the base or precipitating agent into the microemulsion with water solution of metal ions. Similarly, nanoparticles may be prepared of sulphides, halogenides, cyanides, carbonates, sulphates and other insoluble metal salts. To prevent oxidation of nanoparticles, especially Fe, the particles are coated with inert metals, oxides, various polymers etc. Coating may provide additional functionality; e.g. coating with gold allows subsequent functionalization with organic compounds containing sulphur, due to the strong Au–S bond. Polymer coatings decrease

  6. 乙酰丙酮比色法在流感病毒裂解疫苗游离甲醛含量测定中的应用%The application of acetylacetone colorimetric method for determination of free formaldehyde content in influenza vaccine (split virion)

    Institute of Scientific and Technical Information of China (English)

    方曼莉; 马雷钧; 郁佳俊; 封向明; 沈坚; 程鹏飞

    2014-01-01

    目的 验证乙酰丙酮比色法测定流感病毒裂解疫苗游离甲醛含量的可行性,并确认该法测定游离甲醛含量优于品红亚硫酸法. 方法 对乙酰丙酮比色法进行准确度、精密度、专属性、线性、耐用性验证,并将该法与品红亚硫酸法进行比较.结果 乙酰丙酮比色法的标准曲线具有可靠性,甲醛回收率为100.3%~100.9%,相对标准偏差(relative standard deviation,RSD)为0.49%.该法的精密度和专属性良好,实验间和实验内RSD均<5.0%,甲醛加样回收率均>99.0%.与品红亚硫酸法相比,该法的线性更好,偏差更小.结论 乙酰丙酮比色法可用于流感病毒裂解疫苗游离甲醛含量测定.%Objective To validate feasibility of using acetylacetone colorimetric method for determination of free formaldehyde content in influenza vaccine (split virion),and to confirm the acetylacetone colorimetric method was better than the magenta sulphurous acid colorimetric method.Methods The accuracy,precision,specificity,linearity and durability of the acetylacetone colorimetric method were validated.The acetylacetone colorimetric method was compared with the magenta sulphurous acid colorimetric method.Results The standard curve of the acetylacetone colorimetric method was reliable,recoveries of formaldehyde were 100.3%-100.9% and relative standard deviation (RSD) was 0.49%.The precision and specificity of the acetylacetone colorimetric method were good,RSDs of intra-assay and inter-assay were both <5.0% and recoveries of formaldehyde were >99.0%.The acetylacetone method had better linearity and lower deviation as compared with the magenta sulphurous acid colorimetric method.Conclusion The acetylacetone colorimetric method for the determination of free formaldehyde content in influenza vaccine (split virion) is feasible.

  7. Exploring and Implementing Participatory Action Synthesis

    Science.gov (United States)

    Wimpenny, Katherine; Savin-Baden, Maggi

    2012-01-01

    This article presents participatory action synthesis as a new approach to qualitative synthesis which may be used to facilitate the promotion and use of qualitative research for policy and practice. The authors begin by outlining different forms of qualitative research synthesis and then present participatory action synthesis, a collaborative…

  8. Exploring and Implementing Participatory Action Synthesis

    Science.gov (United States)

    Wimpenny, Katherine; Savin-Baden, Maggi

    2012-01-01

    This article presents participatory action synthesis as a new approach to qualitative synthesis which may be used to facilitate the promotion and use of qualitative research for policy and practice. The authors begin by outlining different forms of qualitative research synthesis and then present participatory action synthesis, a collaborative…

  9. Transition Texture Synthesis

    Institute of Scientific and Technical Information of China (English)

    Yueh-Yi Lai; Wen-Kai Tai

    2008-01-01

    Synthesis of transition textures is essential for displaying visually acceptable appearances on a terrain. This investigation presents a modified method for synthesizing the transition texture to be tiled on a terrain. All transition pattern types are recognized for a number of input textures. The proposed modified patch-based sampling texture synthesis approach, using the extra feature map of the input source and target textures for patch matching, can synthesize any transition texture on a succession pattern by initializing the output texture using a portion of the source texture enclosed in a transition cut. The transition boundary is further enhanced to improve the visual effect by tracing out the integral texture elements. Either the Game of Life model or Wang tiles method are exploited to present a good-looking profile of successions on a terrain for tiling transition textures. Experimental results indicate that the proposed method requires few input textures, yet synthesizes numerous tileable transition textures, which are useful for obtaining a vivid appearance of a terrain.

  10. Synthesis of Methylaluminoxane

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Methylaluminoxane (MAO) is the most important cocatalyst of metallocene catalysts. In order to raise the hydrolysis reactions repeatability and the yield,we used the pretreated A12(SO4)3 18H2O to synthesize MAO. A few factors which influence the yield and the cocatalytic activity of MAO were discussed. The optimum condition of the reaction was obtained. The yield of MAO was raised from 40% to 49%. Synthesis of MAO: All the apparatus used was oven dried overnight and cooled under highly pure nitrogen atmosphere before use. The synthesis of MAO is carried out according to the procedure described below. 2M TMA/toluene solution was placed in a 200ml pressure balanced funnel. In a tluee necked 500ml round bottomed flask equipped with a teflon magnetic bar, the pretreated A12(SO4)3.18H2O was dispersed in dry toluene. The first neck was fitted with the pressure balanced funnel with a nitrogen outlet. The second neck was connected to nitrogen inlet. The third neck was connected to a thermowell.

  11. Synthesis of Methylaluminoxane

    Institute of Scientific and Technical Information of China (English)

    ZHU; BoChao

    2001-01-01

    Methylaluminoxane (MAO) is the most important cocatalyst of metallocene catalysts. In order to raise the hydrolysis reactions repeatability and the yield,we used the pretreated A12(SO4)3 18H2O to synthesize MAO. A few factors which influence the yield and the cocatalytic activity of MAO were discussed. The optimum condition of the reaction was obtained. The yield of MAO was raised from 40% to 49%.  Synthesis of MAO: All the apparatus used was oven dried overnight and cooled under highly pure nitrogen atmosphere before use. The synthesis of MAO is carried out according to the procedure described below.   2M TMA/toluene solution was placed in a 200ml pressure balanced funnel. In a tluee necked 500ml round bottomed flask equipped with a teflon magnetic bar, the pretreated A12(SO4)3.18H2O was dispersed in dry toluene. The first neck was fitted with the pressure balanced funnel with a nitrogen outlet. The second neck was connected to nitrogen inlet. The third neck was connected to a thermowell.  ……

  12. Organic Synthesis in Space

    Science.gov (United States)

    Sandford, Scott A.; DeVincenzi, Donald (Technical Monitor)

    2002-01-01

    This talk will review our current understanding of the synthesis of organic molecules in space, with particular emphasis on the synthesis of those compounds that may be of prebiotic interest. The talk will address the possibility that molecules created in the interstellar medium may play a role in the origin and evolution of life on planetary surfaces. The various organic and volatile compounds that are now known or suspected to exist in a variety of space environments (stellar outflows, the diffuse interstellar medium, dense molecular clouds, protostellar nebulae, and planetesimal parent bodies in planetary systems) will be reviewed. This information comes largely from the combined applications of observational infrared and radio spectroscopy, laboratory astrophysical simulations, and theoretical astrochemistry. This will be followed by a discussion of the evidence, largely gathered from the laboratory isotopic study of extraterrestrial materials (meteorites and cosmic dust), that interstellar materials, including organics, can and do survive the transition from the interstellar space into forming stellar systems. Once there, some of this material can be delivered largely unaltered to planetary surfaces where it can play key roles in the origin and subsequent evolution of life.

  13. Synthesis Gas Biorefinery.

    Science.gov (United States)

    Dahmen, N; Henrich, E; Henrich, T

    2017-03-23

    Synthesis gas or syngas is an intermediate, which can be produced by gasification from a variety of carbonaceous feedstocks including biomass. Carbon monoxide and hydrogen, the main constituents of syngas, can be subjected to a broad range of chemical and microbial synthesis processes, leading to gaseous and liquid hydrocarbon fuels as well as to platform and fine chemicals. Gasification of solid biomass differs from coal gasification by chemical composition, heating value, ash behavior, and other technical and biomass related issues. By thermochemical pre-treatment of lignocellulose as the most abundant form of biomass, for example, by torrefaction or fast pyrolysis, energy dense fuels for gasification can be obtained, which can be used in the different types of gasifiers available today. A number of pilot and demonstration plants exist, giving evidence of the broad technology portfolio developed so far. Therefore, a syngas biorefinery is highly flexible in regard to feedstock and product options. However, the technology is complex and does not result in competitive production costs today. Added value can be generated by suitable integration of thermochemical, biochemical, and chemical processes.

  14. Oxygenates vs. synthesis gas

    Energy Technology Data Exchange (ETDEWEB)

    Kamil Klier; Richard G. Herman; Alessandra Beretta; Maria A. Burcham; Qun Sun; Yeping Cai; Biswanath Roy

    1999-04-01

    Methanol synthesis from H{sub 2}/CO has been carried out at 7.6 MPa over zirconia-supported copper catalysts. Catalysts with nominal compositions of 10/90 mol% and 30/70 mol% Cu/ZrO{sub 2} were used in this study. Additionally, a 3 mol% cesium-doped 10/90 catalyst was prepared to study the effect of doping with heavy alkali, and this promoter greatly increased the methanol productivity. The effects of CO{sub 2} addition, water injection, reaction temperature, and H{sub 2}/C0 ratio have been investigated. Both CO{sub 2} addition to the synthesis gas and cesium doping of the catalyst promoted methanol synthesis, while inhibiting the synthesis of dimethyl ether. Injection of water, however, was found to slightly suppress methanol and dimethyl ether formation while being converted to CO{sub 2} via the water gas shift reaction over these catalysts. There was no clear correlation between copper surface area and catalyst activity. Surface analysis of the tested samples revealed that copper tended to migrate and enrich the catalyst surface. The concept of employing a double-bed reactor with a pronounced temperature gradient to enhance higher alcohol synthesis was explored, and it was found that utilization of a Cs-promoted Cu/ZnO/Cr{sub 2}O{sub 3} catalyst as a first lower temperature bed and a Cs-promoted ZnO/Cr{sub 2}O{sub 3} catalyst as a second high-temperature bed significantly promoted the productivity of 2-methyl-1-propanol (isobutanol) from H{sub 2}/CO synthesis gas mixtures. While the conversion of CO to C{sub 2+} oxygenates over the double-bed configuration was comparable to that observed over the single Cu-based catalyst, major changes in the product distribution occurred by the coupling to the zinc chromite catalyst; that is, the productivity of the C{sub 1}-C{sub 3} alcohols decreased dramatically, and 2-methyl branched alcohols were selectively formed. The desirable methanol/2-methyl oxygenate molar ratios close to 1 were obtained in the present double

  15. Organic Synthesis in Space

    Science.gov (United States)

    Sandford, Scott A.; DeVincenzi, Donald (Technical Monitor)

    2002-01-01

    This talk will review our current understanding of the synthesis of organic molecules in space, with particular emphasis on the synthesis of those compounds that may be of prebiotic interest. The talk will address the possibility that molecules created in the interstellar medium may play a role in the origin and evolution of life on planetary surfaces. The various organic and volatile compounds that are now known or suspected to exist in a variety of space environments (stellar outflows, the diffuse interstellar medium, dense molecular clouds, protostellar nebulae, and planetesimal parent bodies in planetary systems) will be reviewed. This information comes largely from the combined applications of observational infrared and radio spectroscopy, laboratory astrophysical simulations, and theoretical astrochemistry. This will be followed by a discussion of the evidence, largely gathered from the laboratory isotopic study of extraterrestrial materials (meteorites and cosmic dust), that interstellar materials, including organics, can and do survive the transition from the interstellar space into forming stellar systems. Once there, some of this material can be delivered largely unaltered to planetary surfaces where it can play key roles in the origin and subsequent evolution of life.

  16. Synthesis of Enantiomerically Pure Anthracyclinones

    Science.gov (United States)

    Achmatowicz, Osman; Szechner, Barbara

    The anthracycline antibiotics are among the most important clinical drugs used in the treatment of human cancer. The search for new agents with improved therapeutic efficacy and reduced cardiotoxicity stimulated considerable efforts in the synthesis of new analogues. Since the biological activity of anthracyclines depends on their natural absolute configuration, various strategies for the synthesis of enantiomerically pure anthracyclinones (aglycones) have been developed. They comprise: resolution of racemic intermediate, incorporation of a chiral fragment derived from natural and non-natural chiral pools, asymmetric synthesis with the use of a chiral auxiliary or a chiral reagent, and enantioselective catalysis. Synthetic advances towards enantiopure anthracyclinones reported over the last 17 years are reviewed.

  17. The Effect of Synthesis Parameters on the Catalytic Synthesis of ...

    African Journals Online (AJOL)

    NJD

    Since the synthesis of carbon nanotubes (CNTs) by Iijima in. 1991 ... emission sources, scanning probes and supports in catalysis.3–5. Several .... powder X-ray spectroscopy (PXRD) were used to confirm the el- emental ... electron beam.

  18. Combinatorial materials synthesis

    Directory of Open Access Journals (Sweden)

    Ichiro Takeuchi

    2005-10-01

    Full Text Available The pace at which major technological changes take place is often dictated by the rate at which new materials are discovered, and the timely arrival of new materials has always played a key role in bringing advances to our society. It is no wonder then that the so-called combinatorial or high-throughput strategy has been embraced by practitioners of materials science in virtually every field. High-throughput experimentation allows simultaneous synthesis and screening of large arrays of different materials. Pioneered by the pharmaceutical industry, the combinatorial method is now widely considered to be a watershed in accelerating the discovery and optimization of new materials1–5.

  19. Isobutanol synthesis from syngas

    Energy Technology Data Exchange (ETDEWEB)

    Falter, W.; Finkeldei, C.H.; Jaeger, B.; Keim, W.; Verkerk, K.A.N. [Institut fuer Technische Chemie und Petrolchemie der Rheinisch-Westfaelischen Technischen Hochschule Aachen, Aachen (Germany)

    1998-12-31

    The increased demand for MTBE (methyl-t-butyl ether) as gasoline additive has attracted attention to alternative pathways for their production. Within this respect the synthesis of higher alcohols by CO hydrogenation has gained new interest, since the selective production of isobutanol-methanol mixtures could offer a possible route. Using a Zr/Zn/Mn/K/Pd catalyst at 400-450 C, 250 bar pressure, 20.000 GHSV/h{sup -1} space time yields of 700-750 g {center_dot} 1{sup -1} {center_dot} h{sup -1} of isobutanol could be obtained. A comparison was made using a fixed bed (tubular) and a CSTR reactor system. 3 refs.

  20. Fiber draw synthesis

    Science.gov (United States)

    Orf, Nicholas D.; Shapira, Ofer; Sorin, Fabien; Danto, Sylvain; Baldo, Marc A.; Joannopoulos, John D.; Fink, Yoel

    2011-01-01

    The synthesis of a high-melting temperature semiconductor in a low-temperature fiber drawing process is demonstrated, substantially expanding the set of materials that can be incorporated into fibers. Reagents in the solid state are arranged in proximate domains within a fiber preform. The preform is fluidized at elevated temperatures and drawn into fiber, reducing the lateral dimensions and bringing the domains into intimate contact to enable chemical reaction. A polymer preform containing a thin layer of selenium contacted by tin–zinc wires is drawn to yield electrically contacted crystalline ZnSe domains of sub-100-nm scales. The in situ synthesized compound semiconductor becomes the basis for an electronic heterostructure diode of arbitrary length in the fiber. The ability to synthesize materials within fibers while precisely controlling their geometry and electrical connectivity at submicron scales presents new opportunities for increasing the complexity and functionality of fiber structures.

  1. Environment Assumptions for Synthesis

    CERN Document Server

    Chatterjee, Krishnendu; Jobstmann, Barbara

    2008-01-01

    The synthesis problem asks to construct a reactive finite-state system from an $\\omega$-regular specification. Initial specifications are often unrealizable, which means that there is no system that implements the specification. A common reason for unrealizability is that assumptions on the environment of the system are incomplete. We study the problem of correcting an unrealizable specification $\\phi$ by computing an environment assumption $\\psi$ such that the new specification $\\psi\\to\\phi$ is realizable. Our aim is to construct an assumption $\\psi$ that constrains only the environment and is as weak as possible. We present a two-step algorithm for computing assumptions. The algorithm operates on the game graph that is used to answer the realizability question. First, we compute a safety assumption that removes a minimal set of environment edges from the graph. Second, we compute a liveness assumption that puts fairness conditions on some of the remaining environment edges. We show that the problem of findi...

  2. Synthesis of superhard materials

    Directory of Open Access Journals (Sweden)

    Vladimir L. Solozhenko

    2005-11-01

    Full Text Available The study of solids at high pressures and temperatures is an important area of modern condensed matter physics, chemistry, and materials science. The last decade has seen revolutionary developments in the field of high-pressure experimentation: new types of cells allow a wider range of experiments at higher pressures, and third-generation synchrotrons have brought the possibility of conducting X-ray diffraction experiments that were unthinkable only 10 years ago. In this review, we give some recent examples to illustrate how modern high-pressure tools, such as the diamond anvil cell (DAC, multianvil press, and shock compression, can be used to answer questions relevant to the synthesis of new advanced materials. Our examples will be related mostly to superhard materials.

  3. De Novo Glutamine Synthesis

    Directory of Open Access Journals (Sweden)

    Qiao He MD

    2016-04-01

    Full Text Available Purpose: The aim of this study was to investigate the role of de novo glutamine (Gln synthesis in the proliferation of C6 glioma cells and its detection with 13N-ammonia. Methods: Chronic Gln-deprived C6 glioma (0.06C6 cells were established. The proliferation rates of C6 and 0.06C6 cells were measured under the conditions of Gln deprivation along with or without the addition of ammonia or glutamine synthetase (GS inhibitor. 13N-ammonia uptake was assessed in C6 cells by gamma counting and in rats with C6 and 0.06C6 xenografts by micro–positron emission tomography (PET scanning. The expression of GS in C6 cells and xenografts was assessed by Western blotting and immunohistochemistry, respectively. Results: The Gln-deprived C6 cells showed decreased proliferation ability but had a significant increase in GS expression. Furthermore, we found that low concentration of ammonia was sufficient to maintain the proliferation of Gln-deprived C6 cells, and 13N-ammonia uptake in C6 cells showed Gln-dependent decrease, whereas inhibition of GS markedly reduced the proliferation of C6 cells as well as the uptake of 13N-ammoina. Additionally, microPET/computed tomography exhibited that subcutaneous 0.06C6 xenografts had higher 13N-ammonia uptake and GS expression in contrast to C6 xenografts. Conclusion: De novo Gln synthesis through ammonia–glutamate reaction plays an important role in the proliferation of C6 cells. 13N-ammonia can be a potential metabolic PET tracer for Gln-dependent tumors.

  4. CLEAN CHEMICAL SYNTHESIS IN WATER

    Science.gov (United States)

    Newer green chemistry approach to accomplish chemical synthesis in water is summarized. Recent global developments pertaining to C-C bond forming reactions using metallic reagents and direct use of the renewable materials such as carbohydrates without derivatization are described...

  5. Synthesis in land change science

    DEFF Research Database (Denmark)

    Magliocca, Nicholas R.; Rudel, Thomas K.; Verburg, Peter H.

    2015-01-01

    Global and regional economic and environmental changes are increasingly influencing local land-use, livelihoods, and ecosystems. At the same time, cumulative local land changes are driving global and regional changes in biodiversity and the environment. To understand the causes and consequences...... of these changes, land change science (LCS) draws on a wide array synthetic and meta-study techniques to generate global and regional knowledge from local case studies of land change. Here, we review the characteristics and applications of synthesis methods in LCS and assess the current state of synthetic research...... based on a meta-analysis of synthesis studies from 1995 to 2012. Publication of synthesis research is accelerating, with a clear trend toward increasingly sophisticated and quantitative methods, including meta-analysis. Detailed trends in synthesis objectives, methods, and land change phenomena...

  6. Green chemistry for nanoparticle synthesis.

    Science.gov (United States)

    Duan, Haohong; Wang, Dingsheng; Li, Yadong

    2015-08-21

    The application of the twelve principles of green chemistry in nanoparticle synthesis is a relatively new emerging issue concerning the sustainability. This field has received great attention in recent years due to its capability to design alternative, safer, energy efficient, and less toxic routes towards synthesis. These routes have been associated with the rational utilization of various substances in the nanoparticle preparations and synthetic methods, which have been broadly discussed in this tutorial review. This article is not meant to provide an exhaustive overview of green synthesis of nanoparticles, but to present several pivotal aspects of synthesis with environmental concerns, involving the selection and evaluation of nontoxic capping and reducing agents, the choice of innocuous solvents and the development of energy-efficient synthetic methods.

  7. Cellular proliferation and hypusine synthesis.

    Science.gov (United States)

    Torrelio, B M; Paz, M A; Gallop, P M

    1984-10-01

    Hypusine (N(-)-(4-amino-2-hydroxybutyl) lysine), a spermidine-dependent post-translational protein modification, is synthesized by various mammalian cells in culture. Experiments described in this paper demonstrated a relationship between rates of cellular growth and the synthesis of hypusine. Cells that divide at fast rates have a high rate of hypusine synthesis. In kinetic experiments, a positive relationship is evident between the rates of protein, DNA and hypusine synthesis. Cells seeded at high density, growing non-exponentially, synthesized less hypusine than logarithmically growing cells seeded at low density. Slowing the growth rate of cells by modification of the external milieu also results in a decreased rate of hypusine synthesis. These results provide additional evidence of the association of hypusine with cell proliferation in cultured cell lines and suggest a possible role for this unusual post-translational modification in the complex macromolecular events leading to cellular growth.

  8. Vanillin Synthesis from 4-Hydroxybenzaldehyde

    Science.gov (United States)

    Taber, Douglass F.; Patel, Shweta; Hambleton, Travis M.; Winkel, Emma E.

    2007-01-01

    A regioselective, safe and efficient method for the synthesis of vanillin from 4-hydroxybenzaldehyde is being described. The vanillin derived from the process is cheap and can be used as a flavor or in the paper industry.

  9. Comparison of genome size and synthesis of structural proteins of Hirame Rhabdovirus, infectious hematopoietic necrosis virus, and viral hemorrhagic Septicemia virus

    Science.gov (United States)

    Nishizawa, Toyohiko; Yoshimizu, Mamoru; Winton, James R.; Kimura, Takahisa

    1991-01-01

    Genomic RNA was extracted from purified virions of hirame rhabdovirus (HRV), infectious hematopoietic necrosis virus (IHNV), and viral hemorrhagic septicemia virus (VHSV). The full-length RNA was analyzed using formaldehyde agarose gel electrophoresis followed by ethidium bromide staining. Compared with an internal RNA size standard, all three viral genomic RNAs appeared to have identical relative mobilities and were estimated to be approximately 10.7 kilobases in length or about 3.7 megadaltons in molecular mass. Structural protein synthesis of HRV, IHNV, and VHSV was studied using cell cultures treated with actinomycin D. At 2 h intervals, proteins were labeled with 35S-methionine, extracted, and analyzed by SDS-polyacrylamide gel electrophoresis and autoradiography. The five structural proteins of each of the three viruses appeared in the following order : nucleoprotein (N), matrix protein 1 (M1), matrix protein 2 (M2), glycoprotein (G), and polymerase (L) reflecting both the approximate relative abundance of each protein within infected cells and the gene order within the viral genome.

  10. Essentials of inorganic materials synthesis

    CERN Document Server

    Rao, C N R

    2015-01-01

    This compact handbook describes all the important methods of synthesis employed today for synthesizing inorganic materials. Some features: Focuses on modern inorganic materials with applications in nanotechnology, energy materials, and sustainability Synthesis is a crucial component of materials science and technology; this book provides a simple introduction as well as an updated description of methods Written in a very simple style, providing references to the literature to get details of the methods of preparation when required

  11. Molybdenum oxide nanowires: synthesis & properties

    Directory of Open Access Journals (Sweden)

    Liqiang Mai

    2011-07-01

    Full Text Available Molybdenum oxide nanowires have been found to show promise in a diverse range of applications, ranging from electronics to energy storage and micromechanics. This review focuses on recent research on molybdenum oxide nanowires: from synthesis and device assembly to fundamental properties. The synthesis of molybdenum oxide nanowires will be reviewed, followed by a discussion of recent progress on molybdenum oxide nanowire based devices and an examination of their properties. Finally, we conclude by considering future developments.

  12. Diamond Synthesis Employing Nanoparticle Seeds

    Science.gov (United States)

    Uppireddi, Kishore (Inventor); Morell, Gerardo (Inventor); Weiner, Brad R. (Inventor)

    2014-01-01

    Iron nanoparticles were employed to induce the synthesis of diamond on molybdenum, silicon, and quartz substrates. Diamond films were grown using conventional conditions for diamond synthesis by hot filament chemical vapor deposition, except that dispersed iron oxide nanoparticles replaced the seeding. This approach to diamond induction can be combined with dip pen nanolithography for the selective deposition of diamond and diamond patterning while avoiding surface damage associated to diamond-seeding methods.

  13. Principles of digital image synthesis

    CERN Document Server

    Glassner, Andrew S

    1995-01-01

    Image synthesis, or rendering, is a field of transformation: it changesgeometry and physics into meaningful images. Because the most popularalgorithms frequently change, it is increasingly important for researchersand implementors to have a basic understanding of the principles of imagesynthesis. Focusing on theory, Andrew Glassner provides a comprehensiveexplanation of the three core fields of study that come together to formdigital image synthesis: the human visual system, digital signalprocessing, and the interaction of matter and light. Assuming no more thana basic background in calculus,

  14. Synthesis of ferroelectric nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Roervik, Per Martin

    2008-12-15

    The increasing miniaturization of electric and mechanical components makes the synthesis and assembly of nanoscale structures an important step in modern technology. Functional materials, such as the ferroelectric perovskites, are vital to the integration and utility value of nanotechnology in the future. In the present work, chemical methods to synthesize one-dimensional (1D) nanostructures of ferroelectric perovskites have been studied. To successfully and controllably make 1D nanostructures by chemical methods it is very important to understand the growth mechanism of these nanostructures, in order to design the structures for use in various applications. For the integration of 1D nanostructures into devices it is also very important to be able to make arrays and large-area designed structures from the building blocks that single nanostructures constitute. As functional materials, it is of course also vital to study the properties of the nanostructures. The characterization of properties of single nanostructures is challenging, but essential to the use of such structures. The aim of this work has been to synthesize high quality single-crystalline 1D nanostructures of ferroelectric perovskites with emphasis on PbTiO3 , to make arrays or hierarchical nanostructures of 1D nanostructures on substrates, to understand the growth mechanisms of the 1D nanostructures, and to investigate the ferroelectric and piezoelectric properties of the 1D nanostructures. In Paper I, a molten salt synthesis route, previously reported to yield BaTiO3 , PbTiO3 and Na2Ti6O13 nanorods, was re-examined in order to elucidate the role of volatile chlorides. A precursor mixture containing barium (or lead) and titanium was annealed in the presence of NaCl at 760 degrees Celsius or 820 degrees Celsius. The main products were respectively isometric nanocrystalline BaTiO3 and PbTiO3. Nanorods were also detected, but electron diffraction revealed that the composition of the nanorods was

  15. Synthesis of ferroelectric nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Roervik, Per Martin

    2008-12-15

    The increasing miniaturization of electric and mechanical components makes the synthesis and assembly of nanoscale structures an important step in modern technology. Functional materials, such as the ferroelectric perovskites, are vital to the integration and utility value of nanotechnology in the future. In the present work, chemical methods to synthesize one-dimensional (1D) nanostructures of ferroelectric perovskites have been studied. To successfully and controllably make 1D nanostructures by chemical methods it is very important to understand the growth mechanism of these nanostructures, in order to design the structures for use in various applications. For the integration of 1D nanostructures into devices it is also very important to be able to make arrays and large-area designed structures from the building blocks that single nanostructures constitute. As functional materials, it is of course also vital to study the properties of the nanostructures. The characterization of properties of single nanostructures is challenging, but essential to the use of such structures. The aim of this work has been to synthesize high quality single-crystalline 1D nanostructures of ferroelectric perovskites with emphasis on PbTiO3 , to make arrays or hierarchical nanostructures of 1D nanostructures on substrates, to understand the growth mechanisms of the 1D nanostructures, and to investigate the ferroelectric and piezoelectric properties of the 1D nanostructures. In Paper I, a molten salt synthesis route, previously reported to yield BaTiO3 , PbTiO3 and Na2Ti6O13 nanorods, was re-examined in order to elucidate the role of volatile chlorides. A precursor mixture containing barium (or lead) and titanium was annealed in the presence of NaCl at 760 degrees Celsius or 820 degrees Celsius. The main products were respectively isometric nanocrystalline BaTiO3 and PbTiO3. Nanorods were also detected, but electron diffraction revealed that the composition of the nanorods was

  16. Gold-Catalyzed Synthesis of Heterocycles

    Science.gov (United States)

    Arcadi, Antonio

    2014-04-01

    The following sections are included: * Introduction * Synthesis of Heterocycles via Gold-Catalyzed Heteroatom Addition to Unsaturated C-C Bonds * Synthesis of Heterocyclic Derivatives through Gold-Catalyzed Cyclization of Polyunsaturated Compounds * Synthesis of Heterocyclic Compounds via α-Oxo Gold Carbenoid * Synthesis of Heterocyclic Derivatives through Gold-Catalyzed Cycloaddition Reactions * Synthesis of Heterocyclic Derivatives through Gold-Catalyzed Activation of Carbonyl Groups and Alcohols * Synthesis of Heterocyclic Compounds through Gold-Mediated C-H Bond Functionalization * Gold-Catalyzed Domino Cyclization/Oxidative Coupling Reactions * Conclusions * References

  17. Synthesis of nanostructured polyaniline

    Science.gov (United States)

    Surwade, Sumedh P.

    The organization of my thesis is as follows: (a) Chapter III describes the synthesis of bulk quantities of polyaniline nanofibers in one step using a simple and versatile high ionic strength aqueous system (HCl/NaCl) that permits the use of pure H2O2 as a mild oxidant without any added metal or enzyme catalyst. Polyaniline nanofibers obtained are highly conducting, sigma˜1--5 S/cm, and spectroscopically similar to conventional polyaniline synthesized using stronger oxidants. The synthesis method is further extended to the synthesis of oligoanilines of controlled molecular weight, e.g., aniline tetramer, octamer, and hexadecamer. Microns long tetramer nanofibers are synthesized using this method. (b) Chapter IV describes the mechanism of nanofiber formation in polyaniline. It is proposed that the surfaces such as the walls of the reaction vessel and/or intentionally added surfaces play a dramatic role in the evolution of nanofibrillar morphology. Nucleation sites on surfaces promote the accumulation of aniline dimer that reacts further to yield aniline tetramer, which (surprisingly) is entirely in form of nanofibers and whose morphology is transcribed to the bulk by a double heterogeneous nucleation mechanism. This unexpected phenomenon could form the basis of nanofiber formation in all classes of precipitation polymerization systems. (c) Chapter V is the mechanistic study on the formation of oligoanilines during the chemical oxidation of aniline in weakly acidic, neutral or basic media using peroxydisulfate oxidant. It is proposed that the reaction proceeds via the intermediacy of benzoquinone monoimine that is formed as a result of a Boyland-Sims rearrangement of aniline. The initial role of peroxydisulfate is to provide a pathway for the formation of benzoquinone monoimine intermediate that is followed by a conjugate Michael-type addition reaction with aniline or sulfated anilines. The products isolated in pH 2.5--10.0 buffers are intermediate species at various

  18. Synthesis of Modified Methylaluminoxane

    Institute of Scientific and Technical Information of China (English)

    Zhu Bo-chao; Zhao Xu-tao; Yin Yuan-qi; Wei Shao-yi

    2004-01-01

    Methylaluminoxane (MAO) is one of the most important cocatalysts of metallocene catalysts. The yield and activity of MAO is low when using Al2(SO4)3 nH2O and other inorganic hydrates to synthesize methylaluminoxane. The repeatability of this reaction is not good. The product cost is very high because one of the raw materials (Trimethylaluminium, TMA) to prepare MAO is very expensive. In addition, on standing, MAO toluene solution tends to gel. Gelled MAO can not be used to prepare supported metallocene catalyets.With the development of gas phase and slurry polymerization of olefine by metallocene catalysts,the application of supported metallocene catalysts becomes more and more important.This paper relates to the use of trimethylaluminium (TMA), tri-isobutylaluminium(TIBA) and silica gel containing from about 4 to about 22 percent by weight absorbed water to synthesize modified methylaluminoxane (MMAO). This method, which integrates synthesis and supporting of MMAO, simplify the preparing process of metallocene catalysts. By using this method, the yield and activity of modified methylaluminoxane is higher than using Al2(SO4)3 nH2O and other inorganic hydrates, and what is more, not only the product cost is lowered, but also gelled MAO is avoided. In addition, the repeatability of this reaction is much better because TIBA is stabler than TMA.Synthesis of Modified MAO: A one liter three neck flask equipped with a magnetic stirring bar and a constant pressure funnel was charged with 250ml of dried and degassed toluene. 60g of undehydrated silica gel (Davison 955) which contains 12 weight percent absorbed water was added into the flask. The resulting mixture was stirred at -10℃ for 30 minutes. Thereafter 90ml of trimethylaluminum/toluene solution (2.0M) was dropped slowly into the flask in 60 minutes. The resulting mixture was allowed to react under stirring at -10℃ for 1hours, then at 0℃ for 1 hours,then at ambient temperature for 1 hours and finally at 40

  19. Arctic freshwater synthesis: Introduction

    Science.gov (United States)

    Prowse, T.; Bring, A.; Mârd, J.; Carmack, E.

    2015-11-01

    In response to a joint request from the World Climate Research Program's Climate and Cryosphere Project, the International Arctic Science Committee, and the Arctic Council's Arctic Monitoring and Assessment Program, an updated scientific assessment has been conducted of the Arctic Freshwater System (AFS), entitled the Arctic Freshwater Synthesis (AFSΣ). The major reason for joint request was an increasing concern that changes to the AFS have produced, and could produce even greater, changes to biogeophysical and socioeconomic systems of special importance to northern residents and also produce extra-Arctic climatic effects that will have global consequences. Hence, the key objective of the AFSΣ was to produce an updated, comprehensive, and integrated review of the structure and function of the entire AFS. The AFSΣ was organized around six key thematic areas: atmosphere, oceans, terrestrial hydrology, terrestrial ecology, resources and modeling, and the review of each coauthored by an international group of scientists and published as separate manuscripts in this special issue of Journal of Geophysical Research-Biogeosciences. This AFSΣ—Introduction reviews the motivations for, and foci of, previous studies of the AFS, discusses criteria used to define the domain of the AFS, and details key characteristics of the definition adopted for the AFSΣ.

  20. Synthesis of P005091

    Directory of Open Access Journals (Sweden)

    Ping YU

    2016-06-01

    Full Text Available To improve the synthesis method of P005091 (1-(5-((2,3-dichlorophenyl thio-4-nitro-2-thienyl ethanone, with 2-chlorothiophene as the starting material, acetyl chloride as the acetylation reagent and aluminium trichloride as the catalyst, acetyl is introduced in the 5th position of 2-chlorothiophene to get 2-acetyl-5-chlorothiophene (compound 2, and the yield is 91%; then with concentrated sulfuric acid as solvent and mixed acid as nitrating agent, 5-acetyl-2-chloro-3-nitrothiophene (compound 3 is obtained by nitration reaction with compound 2, and the yield is 64%; thioetherfication reaction of compound 3 and 2,3-dichlorobenzenethiol in DMF solution under the function of potassium carbonate takes place to obtain the target product P005091, and the yield is 76%. The structure of P005091 is confirmed by mp, 1H-NMR, 13C-NMR and MS, and the overall yield is 44%. The improved method has the advantages of low cost, simple operation, and a milder reaction condition compared with the former references, avoiding using the reagent with higher toxicity, and high yield on the premise that the product purity is assured.

  1. Steroidal Triterpenes of Cholesterol Synthesis

    Directory of Open Access Journals (Sweden)

    Damjana Rozman

    2013-04-01

    Full Text Available Cholesterol synthesis is a ubiquitous and housekeeping metabolic pathway that leads to cholesterol, an essential structural component of mammalian cell membranes, required for proper membrane permeability and fluidity. The last part of the pathway involves steroidal triterpenes with cholestane ring structures. It starts by conversion of acyclic squalene into lanosterol, the first sterol intermediate of the pathway, followed by production of 20 structurally very similar steroidal triterpene molecules in over 11 complex enzyme reactions. Due to the structural similarities of sterol intermediates and the broad substrate specificity of the enzymes involved (especially sterol-Δ24-reductase; DHCR24 the exact sequence of the reactions between lanosterol and cholesterol remains undefined. This article reviews all hitherto known structures of post-squalene steroidal triterpenes of cholesterol synthesis, their biological roles and the enzymes responsible for their synthesis. Furthermore, it summarises kinetic parameters of enzymes (Vmax and Km and sterol intermediate concentrations from various tissues. Due to the complexity of the post-squalene cholesterol synthesis pathway, future studies will require a comprehensive meta-analysis of the pathway to elucidate the exact reaction sequence in different tissues, physiological or disease conditions. A major reason for the standstill of detailed late cholesterol synthesis research was the lack of several steroidal triterpene standards. We aid to this efforts by summarizing commercial and laboratory standards, referring also to chemical syntheses of meiosis-activating sterols.

  2. synthesis, characterization, thermal behavior and antimicrobial ...

    African Journals Online (AJOL)

    The design and synthesis of ... The double distilled water was used for the preparation and chemical analyses. ... Synthesis of 3-methyl benzoate complexes of transition metal with hydrazine. Bull. Chem. Soc. ..... hinder the respiration process of the cell and thus block the synthesis of the proteins, restricting further growth of ...

  3. Collaboration and Productivity in Scientific Synthesis

    Science.gov (United States)

    Hampton, Stephanie E.; Parker, John N.

    2011-01-01

    Scientific synthesis has transformed ecological research and presents opportunities for advancements across the sciences; to date, however, little is known about the antecedents of success in synthesis. Building on findings from 10 years of detailed research on social interactions in synthesis groups at the National Center for Ecological Analysis…

  4. Spectral Synthesis of SDSS Galaxies

    CERN Document Server

    Sodre, J; Mateus, A; Stasinska, G; Gomes, J M

    2005-01-01

    We investigate the power of spectral synthesis as a mean to estimate physical properties of galaxies. Spectral synthesis is nothing more than the decomposition of an observed spectrum in terms of a superposition of a base of simple stellar populations of various ages and metallicities (here from Bruzual & Charlot 2003), producing as output the star-formation and chemical histories of a galaxy, its extinction and velocity dispersion. We discuss the reliability of this approach and apply it to a volume limited sample of 50362 galaxies from the SDSS Data Release 2, producing a catalog of stellar population properties. A comparison with recent estimates of both observed and physical properties of these galaxies obtained by other groups shows good qualitative and quantitative agreement, despite substantial differences in the method of analysis. The confidence in the method is further strengthened by several empirical and astrophysically reasonable correlations between synthesis results and independent quantiti...

  5. Sustainable Process Synthesis-Intensification

    DEFF Research Database (Denmark)

    Babi, Deenesh Kavi

    . Therefore sustainable process design can be achieved by performing process syn-thesis and process intensification together. The main contribution of this work is the development of a systematic computer-aided multi-scale, multi-level framework for performing process synthesis-intensification that aims...... operations scale a conceptual base case design is synthesized through the sequencing of unit operations. The base case is then designed and analysed for identifying process limitations or bottlenecks (hot-spots) using a comprehensive analysis consisting of economic, life cycle and sustainability analyses...... that are translated into design targets. These hot-spots are associated with tasks that may be targeted for overall process improvement. Next an integrated task-phenomena-based synthesis method is applied, where the involved phenomena in various tasks are identified, manipulated and recombined using combination rules...

  6. Synthesis and Characterization of Multithiouracils

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; LIU Hui-Min; ZHANG Wei; ZHANG Wen-Qin

    2003-01-01

    @@ Alkylation of bases group of nucleic acid, thymine and uracil, has attracted great attention. In order to investigate the intermolecular interactions, [1,2] and the photoreactions[3,4] between bases group of nucleic acid, many studies were focused on the synthesis of bisbases in the formation of B-(CH2)n-B (B′) in which trimethylene was commonly used as linker. Thiouracil is an important derivative of nucleic acid bases, and it can interfere with the synthesis of thyroxine, especially in the treatment of hyperthyroidism and angina. However, to our knowledge, the synthesis of bisthiouracils, even trithiouracils, using flexible or rigid linkers has not been reported. Herein, we have synthesized eight thiouracil derivatives by nucleophilic reaction between thiouracil and varied bromides. All the compounds have been characterized by IR, 1H NMR and element analysis.

  7. Electrochemical synthesis of electroconducting polymers

    Directory of Open Access Journals (Sweden)

    Gvozdenović Milica M.

    2014-01-01

    Full Text Available Electroconducting polymers from the group of synthetic metals are extensively investigated due to numerous properties perspective in practical application. These materials may be synthesized by both chemical and electrochemical procedures. Chemical synthesis is suitable when bulk quantities of the polymer are needed and up to date it presents dominant commercial method of producing electroconducting polymers. Nevertheless, electrochemical synthesis has its advantages; it avoids usage of oxidants since conducting polymeric material is obtained at anode upon application of positive potential, leading to increased purity. On the other hand, since the polymer is deposited onto electrode, further electrochemical characterization is facilitated. Owing to actuality of the research in the field this texts aims to describe important aspects of electrochemical synthesis of electroconducting polymers, with special emphasis to polyaniline and polypyrrole. [Projekat Ministarstva nauke Republike Srbije, br. 172046

  8. A Short Synthesis of (+)-Cyclophellitol

    DEFF Research Database (Denmark)

    Hansen, Flemming Gundorph; Bundgaard, Eva; Madsen, Robert

    2005-01-01

    A new synthesis of (+)-cyclophellitol, a potent b-glucosidase inhibitor, has been completed in nine steps from D-xylose. The key transformations involve a zinc-mediated fragmentation of benzyl-protected methyl 5-deoxy-5-iodo-xylofuranoside followed by a highly diastereoselective indium-mediated c......A new synthesis of (+)-cyclophellitol, a potent b-glucosidase inhibitor, has been completed in nine steps from D-xylose. The key transformations involve a zinc-mediated fragmentation of benzyl-protected methyl 5-deoxy-5-iodo-xylofuranoside followed by a highly diastereoselective indium......-mediated coupling with ethyl 4-bromocrotonate. Subsequent ring-closing olefin metathesis, ester reduction, olefin epoxidation, and deprotection then afford the natural product. This constitutes the shortest synthesis of (+)-cyclophellitol reported to date....

  9. Structural synthesis of parallel robots

    CERN Document Server

    Gogu, Grigore

    This book represents the fifth part of a larger work dedicated to the structural synthesis of parallel robots. The originality of this work resides in the fact that it combines new formulae for mobility, connectivity, redundancy and overconstraints with evolutionary morphology in a unified structural synthesis approach that yields interesting and innovative solutions for parallel robotic manipulators.  This is the first book on robotics that presents solutions for coupled, decoupled, uncoupled, fully-isotropic and maximally regular robotic manipulators with Schönflies motions systematically generated by using the structural synthesis approach proposed in Part 1.  Overconstrained non-redundant/overactuated/redundantly actuated solutions with simple/complex limbs are proposed. Many solutions are presented here for the first time in the literature. The author had to make a difficult and challenging choice between protecting these solutions through patents and releasing them directly into the public domain. T...

  10. Synthesis metal nanoparticle

    Science.gov (United States)

    Bunge, Scott D.; Boyle, Timothy J.

    2005-08-16

    A method for providing an anhydrous route for the synthesis of amine capped coinage-metal (copper, silver, and gold) nanoparticles (NPs) using the coinage-metal mesityl (mesityl=C.sub.6 H.sub.2 (CH.sub.3).sub.3 -2,4,6) derivatives. In this method, a solution of (Cu(C.sub.6 H.sub.2 (CH.sub.3).sub.3).sub.5, (Ag(C.sub.6 H.sub.2 (CH.sub.3).sub.3).sub.4, or (Au(C.sub.6 H.sub.2 (CH.sub.3).sub.3).sub.5 is dissolved in a coordinating solvent, such as a primary, secondary, or tertiary amine; primary, secondary, or tertiary phosphine, or alkyl thiol, to produce a mesityl precursor solution. This solution is subsequently injected into an organic solvent that is heated to a temperature greater than approximately 100.degree. C. After washing with an organic solvent, such as an alcohol (including methanol, ethanol, propanol, and higher molecular-weight alcohols), oxide free coinage NP are prepared that could be extracted with a solvent, such as an aromatic solvent (including, for example, toluene, benzene, and pyridine) or an alkane (including, for example, pentane, hexane, and heptane). Characterization by UV-Vis spectroscopy and transmission electron microscopy showed that the NPs were approximately 9.2.+-.2.3 nm in size for Cu.degree., (no surface oxide present), approximately 8.5.+-.1.1 nm Ag.degree. spheres, and approximately 8-80 nm for Au.degree..

  11. Sterol Synthesis in Diverse Bacteria.

    Science.gov (United States)

    Wei, Jeremy H; Yin, Xinchi; Welander, Paula V

    2016-01-01

    Sterols are essential components of eukaryotic cells whose biosynthesis and function has been studied extensively. Sterols are also recognized as the diagenetic precursors of steranes preserved in sedimentary rocks where they can function as geological proxies for eukaryotic organisms and/or aerobic metabolisms and environments. However, production of these lipids is not restricted to the eukaryotic domain as a few bacterial species also synthesize sterols. Phylogenomic studies have identified genes encoding homologs of sterol biosynthesis proteins in the genomes of several additional species, indicating that sterol production may be more widespread in the bacterial domain than previously thought. Although the occurrence of sterol synthesis genes in a genome indicates the potential for sterol production, it provides neither conclusive evidence of sterol synthesis nor information about the composition and abundance of basic and modified sterols that are actually being produced. Here, we coupled bioinformatics with lipid analyses to investigate the scope of bacterial sterol production. We identified oxidosqualene cyclase (Osc), which catalyzes the initial cyclization of oxidosqualene to the basic sterol structure, in 34 bacterial genomes from five phyla (Bacteroidetes, Cyanobacteria, Planctomycetes, Proteobacteria, and Verrucomicrobia) and in 176 metagenomes. Our data indicate that bacterial sterol synthesis likely occurs in diverse organisms and environments and also provides evidence that there are as yet uncultured groups of bacterial sterol producers. Phylogenetic analysis of bacterial and eukaryotic Osc sequences confirmed a complex evolutionary history of sterol synthesis in this domain. Finally, we characterized the lipids produced by Osc-containing bacteria and found that we could generally predict the ability to synthesize sterols. However, predicting the final modified sterol based on our current knowledge of sterol synthesis was difficult. Some bacteria

  12. Combustion synthesis method and products

    Science.gov (United States)

    Holt, J.B.; Kelly, M.

    1993-03-30

    Disclosed is a method of producing dense refractory products, comprising: (a) obtaining a quantity of exoergic material in powder form capable of sustaining a combustion synthesis reaction; (b) removing absorbed water vapor therefrom; (c) cold-pressing said material into a formed body; (d) plasma spraying said formed body with a molten exoergic material to form a coat thereon; and (e) igniting said exoergic coated formed body under an inert gas atmosphere and pressure to produce self-sustained combustion synthesis. Also disclosed are products produced by the method.

  13. Ferroic materials synthesis and applications

    CERN Document Server

    Virk, Hardev Singh

    2015-01-01

    Ferroics is the generic name given to the study of ferromagnets, ferroelectrics, and ferroelastics. The basis of this study is to understand the large changes in physical characteristics that occur over a very narrow temperature range. In recent years, a new class of ferroic materials has been attracting increased interest. These multiferroics exhibit more than one ferroic property simultaneously in a single phase. The present volume: ""Ferroic Materials: Synthesis and Applications"" has ten Chapters, spread over areas as diverse as Magnetic Oxide Nanomaterials, Ferrites Synthesis, Hexaferrite

  14. Developments of VLBI synthesis mapping.

    Science.gov (United States)

    Jiang, Dongrong; Wan, Tongshan

    1992-12-01

    The authors review the developments of VLBI synthesis mapping. First they give a brief history of VLBI techniques and a summary of some technical parameters frequently used in VLBI synthesis mapping. They then mention problems, namely, (u,v) coverage, correction of errors in visibility data, image quality, GFF (Global Fringe Fitting), field of view, etc. The new developments which are presented include the improvements of (u,v) coverage and angular resolution, Mk III GFF, phase reference mapping, wide field mapping, difference mapping, the potential of space VLBI mapping, mosaicing and non-linear deconvolution.

  15. Heterogeneous photocatalysts in organic synthesis

    Science.gov (United States)

    Cherevatskaya, M.; König, B.

    2014-03-01

    The review deals with the application of inorganic semiconductors in organic synthesis. Although the majority of reported reactions still aim at the photocatalytic decomposition of organic compounds, the number of examples in synthetic applications is growing. The principal mechanisms of heterogeneous semiconductor photocatalysis are considered and examples illustrating the use of inorganic semiconductors in organic synthesis are given. The discussion is arranged according to the required excitation wavelength (UV or visible light) and to the new bond that is formed (carbon-carbon or carbon-heteroatom bond). The bibliography includes 47 references.

  16. Technology of Iron Carbide Synthesis

    Institute of Scientific and Technical Information of China (English)

    M.Bahgat

    2006-01-01

    Iron carbides are very promising metallurgical products and can be used for steelmaking process, where it plays as an alternative raw material with significant economic advantages. Also it has many other applications,e.g. catalysts, magnets, sensors. The present review investigates the different properties and uses of the iron carbides. The commercial production and the different varieties for the iron carbides synthesis (gaseous carburization, mechanochemical synthesis, laser pyrolysis, plasma pyrolysis, chemical vapor deposition and ion implantation) were reviewed. Also the effect of different factors on the carburization process like gas composition, raw material, temperature, reaction time, catalyst presence and sulfur addition was indicated.

  17. Synthesis in land change science

    DEFF Research Database (Denmark)

    Magliocca, Nicholas R.; Rudel, Thomas K.; Verburg, Peter H.

    2015-01-01

    of these changes, land change science (LCS) draws on a wide array synthetic and meta-study techniques to generate global and regional knowledge from local case studies of land change. Here, we review the characteristics and applications of synthesis methods in LCS and assess the current state of synthetic research...... and world regions most commonly studied are presented. Significant challenges to successful synthesis research in LCS are also identified, including issues of interpretability and comparability across case-studies and the limits of and biases in the geographic coverage of case studies. Nevertheless...

  18. Solid-phase peptide synthesis

    DEFF Research Database (Denmark)

    Jensen, Knud Jørgen

    2013-01-01

    This chapter provides an introduction to and overview of peptide chemistry with a focus on solid-phase peptide synthesis. The background, the most common reagents, and some mechanisms are presented. This chapter also points to the different chapters and puts them into perspective.......This chapter provides an introduction to and overview of peptide chemistry with a focus on solid-phase peptide synthesis. The background, the most common reagents, and some mechanisms are presented. This chapter also points to the different chapters and puts them into perspective....

  19. First total synthesis of Boehmenan

    Indian Academy of Sciences (India)

    Yamu Xia; Xiaoli Dai; Haixin Liu; Chen Chai

    2014-05-01

    The first total synthesis of dilignan Boehmenan has been achieved. A biomimetic oxidative coupling of the ferulic acid methyl ester in the presence of silver oxide is the crucial step in the synthesis sequence, generating the dihydrobenzofuran skeleton. Hydroxyl group was protected with DHP and reducted with LiAlH4 to afford the intermediate diol. The diol was condensated with the derivative of ferulic acid, then removed the protecting groups, to get Boehmenan. Meanwhile, a study on the ring-opening reaction of the intermediate dihydrobenzofuran neolignan under base conditions was described.

  20. Insolubilized enzymes for food synthesis

    Science.gov (United States)

    Marshall, D. L.

    1972-01-01

    Cellulose matrix with numerous enzyme-coated silica particles of colloidal size permanently bound at various sites within matrix was produced that has high activity and possesses requisite physical characteristics for filtration or column operations. Product also allows coupling step in synthesis of edible food to proceed under mild conditions.

  1. SYNTHESIS OF ALLENIC NAPHTHALENE DERIVATIVES ...

    African Journals Online (AJOL)

    the synthesis of allenes, reduction of propargylic halides, ethers, or esters with the ... solution, 2-propanol and Pd (PPh3)4 yielded the methyl allene 5b and acetylene ..... by column flash chromatography over silica gel (hexane) affording pure ...

  2. Synthesis and biosynthesis of isocordoin.

    Science.gov (United States)

    Vitali, A; Ferrari, F; Monache, G D; Bombardelli, E; Botta, B

    2001-07-01

    In the search of a convenient synthesis for isocordoin (1), a potential anticancer natural product, 2',4'-dihydroxychalcone was inoculated in cell suspension cultures of Morus nigra, which were expected to contain an active prenyltransferase. After 24 hours the target compound was easily isolated from the metabolite extract. Optimization of the biotransformation resulted in a 85% yield of the prenyl derivative.

  3. Organic chemistry: Streamlining drug synthesis

    Science.gov (United States)

    Hawkins, Joel M.

    2015-04-01

    Drug manufacture can benefit from flow synthesis, in which raw materials are fed into a sequence of reactors, producing the drug as a continuous output. A flow strategy that capitalizes on solid catalysts has now been realized. See Letter p.329

  4. Synthesis of noble metal nanoparticles

    Science.gov (United States)

    Bahadory, Mozhgan

    Improved methods were developed for the synthesis of noble metal nanoparticles. Laboratory experiments were designed for introducing of nanotechnology into the undergraduate curriculum. An optimal set of conditions for the synthesis of clear yellow colloidal silver was investigated. Silver nanoparticles were obtained by borohydride reduction of silver nitrate, a method which produces particles with average size of 12+/-2 nm, determined by Transmission Electron Microscopy (TEM). The plasmon absorbance is at 397 nm and the peak width at half maximum (PWHM) is 70-75 nm. The relationship between aggregation and optical properties was determined along with a method to protect the particles using polyvinylpyrrolidone (PVP). A laboratory experiment was designed in which students synthesize yellow colloidal silver, estimate particle size using visible spectroscopy, and study aggregation effects. The synthesis of the less stable copper nanoparticles is more difficult because copper nanopaticles are easily oxidized. Four methods were used for the synthesis of copper nanoparticles, including chemical reduction with sodium borohydride, sodium borohydride with potassium iodide, isopropyl alcohol with cetyltrimethylammonium bormide (CTAB) and reducing sugars. The latter method was also the basis for an undergraduate laboratory experiment. For each reaction, the dependence of stability of the copper nanoparticles on reagent concentrations, additives, relative amounts of reactants, and temperature is explored. Atomic force microscopy (AFM), TEM and UV-Visible Spectroscopy were used to characterize the copper nanoparticles. A laboratory experiment to produce copper nanoparticles from household chemicals was developed.

  5. Solventless synthesis of ruthenium nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    García-Peña, Nidia G. [Departmento de Tecnociencias, Universidad Nacional Autónoma de México, Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Cd. Universitaria A.P. 70-186, C.P. 04510 Coyoacán, México D.F. (Mexico); Redón, Rocío, E-mail: rredon@unam.mx [Departmento de Tecnociencias, Universidad Nacional Autónoma de México, Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Cd. Universitaria A.P. 70-186, C.P. 04510 Coyoacán, México D.F. (Mexico); Herrera-Gomez, Alberto [Estudios Avanzados del Instituto Politécnico Nacional, Campus Juriquilla, Querétaro (Mexico); Fernández-Osorio, Ana Leticia [FES-Cuautitlán, Universidad Nacional Autónoma de México, Edo. de Mexico (Mexico); Bravo-Sanchez, Mariela; Gomez-Sosa, Gustavo [Estudios Avanzados del Instituto Politécnico Nacional, Campus Juriquilla, Querétaro (Mexico)

    2015-06-15

    Graphical abstract: - Highlights: • Successful synthesis of Ru nanoparticles by a cheap, fast and solventless approach was achieved. • The zero-valent state as well as the by-product/impurity free of the mechanochemical obtained Ru nanoparticles was proven by XPS, TEM and XRD. • Compared to two other synthesis strategies, the above-mentioned synthesis was more suitable to obtain smaller particles with fewer impurities in shorter time. - Abstract: This paper presents a novel solventless method for the synthesis of zero-valent ruthenium nanoparticles Ru(0). The proposed method, although not entirely new in the nanomaterials world, was used for the first time to synthesize zero-valent ruthenium nanoparticles. This new approach has proved to be an environmentally friendly, clean, cheap, fast, and reproducible technique which employs low amounts of solvent. It was optimized through varying amounts of reducing salt on a determined quantity of precursor and measuring the effect of this variation on the average particle size obtained. The resulting products were fully characterized by powder XRD, TEM, HR-TEM, and XPS studies, all of which corroborated the purity of the nanoparticles achieved. In order to verify the advantages of our method over other techniques, we compared our nanoparticles with two common colloidal-synthesized ruthenium nanoparticles.

  6. Digital filter synthesis computer program

    Science.gov (United States)

    Moyer, R. A.; Munoz, R. M.

    1968-01-01

    Digital filter synthesis computer program expresses any continuous function of a complex variable in approximate form as a computational algorithm or difference equation. Once the difference equation has been developed, digital filtering can be performed by the program on any input data list.

  7. Methanol synthesis beyond chemical equilibrium

    NARCIS (Netherlands)

    van Bennekom, J. G.; Venderbosch, R. H.; Winkelman, J. G. M.; Wilbers, E.; Assink, D.; Lemmens, K. P. J.; Heeres, H. J.

    2013-01-01

    In commercial methanol production from syngas, the conversion is thermodynamically limited to 0.3-0.7 leading to large recycles of non-converted syngas. This problem can be overcome to a significant extent by in situ condensation of methanol during its synthesis which is possible nowadays due to the

  8. Catalysis and prebiotic RNA synthesis

    Science.gov (United States)

    Ferris, James P.

    1993-01-01

    The essential role of catalysis for the origins of life is discussed. The status of the prebiotic synthesis of 2',5'- and 3'5'-linked oligomers of RNA is reviewed. Examples of the role of metal ion and mineral catalysis in RNA oligomer formation are discussed.

  9. Compositional synthesis of safety controllers

    NARCIS (Netherlands)

    Kuijper, Wouter

    2012-01-01

    In my thesis I investigate compositional techniques for synthesis of safety controllers. A safety controller, in this context, is a state machine that gives the set of safe control outputs for every possible sequence of observations from the plant under control. Compositionality, in this context, re

  10. SOLID PHASE SYNTHESIS OF ISOXAZOLINES

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The solid-phase synthesis of isoxazolines on 2-polystyrylsulfonamidoethanol resin isreported. 2-Polystyrylsuifonamidoethanol resin 1 was reacted with acryloyl chloride to afford2-polystyrylsulfonylamidoethyl acrylate resin 2, which was further reacted with brominatedaldoximes by [3+2] cycioaddition to give isoxazoline resin 4. Resin 4 was treated with aqueous 6mol/L HCI solution to obtain isoxazolines in good yield and purity.

  11. Synthesis through Trans-disciplinarity

    DEFF Research Database (Denmark)

    Hansen, Hanne Tine Ring

    2006-01-01

    ,and that architects are general regarded as the person responsible for synthesising the different architectural elements that influence spatial and haptic perception. An exemplar of this is Peter Zumthor's thermal baths in Vals, Switzerland, where synthesis between spatiality and tactility, materials and colours...... of the room, colour, tactility and smell of materials, and lighting....

  12. Green chemistry for chemical synthesis

    OpenAIRE

    Li, Chao-Jun; Trost, Barry M.

    2008-01-01

    Green chemistry for chemical synthesis addresses our future challenges in working with chemical processes and products by inventing novel reactions that can maximize the desired products and minimize by-products, designing new synthetic schemes and apparati that can simplify operations in chemical productions, and seeking greener solvents that are inherently environmentally and ecologically benign.

  13. Green chemistry for chemical synthesis

    Science.gov (United States)

    Li, Chao-Jun; Trost, Barry M.

    2008-01-01

    Green chemistry for chemical synthesis addresses our future challenges in working with chemical processes and products by inventing novel reactions that can maximize the desired products and minimize by-products, designing new synthetic schemes and apparati that can simplify operations in chemical productions, and seeking greener solvents that are inherently environmentally and ecologically benign. PMID:18768813

  14. Chronology of a Difficult Synthesis

    Science.gov (United States)

    Menger, Fredric M.; Sorrells, Jennifer L.

    2009-01-01

    This article describes a short synthesis and many of the difficulties experienced while carrying it out (e.g., low yields, impurities, racemization, nonrepeatable literature preps, etc.). As such, students will be educated in aspects of synthetic organic chemistry that are often down-played, or even not mentioned, in published syntheses. (Contains…

  15. A short synthesis of (+/-)-cytisine.

    Science.gov (United States)

    Botuha, Candice; Galley, Carl M S; Gallagher, Timothy

    2004-07-07

    The synthesis of racemic cytisine has been completed using (i)N-selective alkylation of 6-bromopyridone with bromide and (ii) Pd(0) mediated intramolecular alpha-arylation of lactam as key steps to achieve rapid assembly of the tricyclic core skeleton of the lupin alkaloids.

  16. CAPTURED End Evaluation Synthesis Report

    NARCIS (Netherlands)

    Brouwers, J.H.A.M.

    2012-01-01

    This report provides the findings of the Synthesis Study of the CAPTURED Evaluation and is produced as part of the overall CAPTURED End Evaluation. After five years of support by the CAPTURED project the three CAPTURED partners have achieved commendable results. Ten lessons learned are formulated th

  17. Analysis and synthesis of laughter

    Science.gov (United States)

    Sundaram, Shiva; Narayanan, Shrikanth

    2004-10-01

    There is much enthusiasm in the text-to-speech community for synthesis of emotional and natural speech. One idea being proposed is to include emotion dependent paralinguistic cues during synthesis to convey emotions effectively. This requires modeling and synthesis techniques of various cues for different emotions. Motivated by this, a technique to synthesize human laughter is proposed. Laughter is a complex mechanism of expression and has high variability in terms of types and usage in human-human communication. People have their own characteristic way of laughing. Laughter can be seen as a controlled/uncontrolled physiological process of a person resulting from an initial excitation in context. A parametric model based on damped simple harmonic motion to effectively capture these diversities and also maintain the individuals characteristics is developed here. Limited laughter/speech data from actual humans and synthesis ease are the constraints imposed on the accuracy of the model. Analysis techniques are also developed to determine the parameters of the model for a given individual or laughter type. Finally, the effectiveness of the model to capture the individual characteristics and naturalness compared to real human laughter has been analyzed. Through this the factors involved in individual human laughter and their importance can be better understood.

  18. SHORT COMMUNICATION SYNTHESIS AND CRYSTAL ...

    African Journals Online (AJOL)

    Preferred Customer

    In the present contribution the synthesis of the title compound has been performed according to the scheme shown ... to literature [4]. The title compound was synthesized according to following method: 2,2- ... 0.1498, wR2 = 0.1774. Goof value.

  19. Gestural Control Of Wavefield synthesis

    DEFF Research Database (Denmark)

    Grani, Francesco; Di Carlo, Diego; Portillo, Jorge Madrid

    2016-01-01

    Wi- iMote game controller to “throw” sounding objects towards them. Aim of this project was to create a gestural interface for a game based on auditory cues only, and to investigate how convolution reverberation can affects people’s percep- tion of distance in a wavefield synthesis setup environment....

  20. Total synthesis of (-)- and (+)-tedanalactam

    Digital Repository Service at National Institute of Oceanography (India)

    Majik, M.S.; Parameswaran, P.S.; Tilve, S.G.

    -66%); (b) 1. TFA, CH 2 Cl 2 , 0 0 C to room temp, 2h; 2. aq NH 3 (72-77%) Having secured the route in terms of relative stereochemistry, we focused our effort on completing an enantioselective synthesis of tedanalactam. To this end, the diol 7a...

  1. The Total Synthesis of 14-Deoxycrassin and Pseudoplexaurol: A Convergent Synthesis of Cyclization Precursor

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The synthesis of epoxy aldehyde 4, a cyclization precursor for the total synthesis of 14-deoxycrassin and pseudoplexaurol, starting from geraniol in a convergent and stereoselective manner, is described.

  2. Flow “Fine” Synthesis: High Yielding and Selective Organic Synthesis by Flow Methods

    Science.gov (United States)

    2015-01-01

    Abstract The concept of flow “fine” synthesis, that is, high yielding and selective organic synthesis by flow methods, is described. Some examples of flow “fine” synthesis of natural products and APIs are discussed. Flow methods have several advantages over batch methods in terms of environmental compatibility, efficiency, and safety. However, synthesis by flow methods is more difficult than synthesis by batch methods. Indeed, it has been considered that synthesis by flow methods can be applicable for the production of simple gasses but that it is difficult to apply to the synthesis of complex molecules such as natural products and APIs. Therefore, organic synthesis of such complex molecules has been conducted by batch methods. On the other hand, syntheses and reactions that attain high yields and high selectivities by flow methods are increasingly reported. Flow methods are leading candidates for the next generation of manufacturing methods that can mitigate environmental concerns toward sustainable society. PMID:26337828

  3. Physical synthesis of quantum circuits using templates

    Science.gov (United States)

    Mirkhani, Zahra; Mohammadzadeh, Naser

    2016-10-01

    Similar to traditional CMOS circuits, quantum circuit design flow is divided into two main processes: logic synthesis and physical design. Addressing the limitations imposed on optimization of the quantum circuit metrics because of no information sharing between logic synthesis and physical design processes, the concept of " physical synthesis" was introduced for quantum circuit flow, and a few techniques were proposed for it. Following that concept, in this paper a new approach for physical synthesis inspired by template matching idea in quantum logic synthesis is proposed to improve the latency of quantum circuits. Experiments show that by using template matching as a physical synthesis approach, the latency of quantum circuits can be improved by more than 23.55 % on average.

  4. Stereoselective Halogenation in Natural Product Synthesis.

    Science.gov (United States)

    Chung, Won-jin; Vanderwal, Christopher D

    2016-03-24

    At last count, nearly 5000 halogenated natural products have been discovered. In approximately half of these compounds, the carbon atom to which the halogen is bound is sp(3) -hybridized; therefore, there are an enormous number of natural products for which stereocontrolled halogenation must be a critical component of any synthesis strategy. In this Review, we critically discuss the methods and strategies used for stereoselective introduction of halogen atoms in the context of natural product synthesis. Using the successes of the past, we also attempt to identify gaps in our synthesis technology that would aid the synthesis of halogenated natural products, as well as existing methods that have not yet seen application in complex molecule synthesis. The chemistry described herein demonstrates yet again how natural products continue to provide the inspiration for critical advances in chemical synthesis.

  5. Papain-specific activating esters in aqueous dipeptide synthesis.

    NARCIS (Netherlands)

    Beer, R.J. de; Zarzycka, B.; Mariman, M.; Amatdjais-Groenen, H.; Mulders, M.J.; Quaedflieg, P.J.L.M.; Delft, F.L. van; Nabuurs, S.B.; Rutjes, F.P.J.T.

    2012-01-01

    Enzymatic peptide synthesis has the potential to be a viable alternative for chemical peptide synthesis. Because of the increasing commercial interest in peptides, new and improved enzymatic synthesis methods are desirable. In recently developed enzymatic strategies such as substrate mimetic

  6. Stereocontrolled Total Synthesis of (-)-Stemaphylline.

    Science.gov (United States)

    Varela, Ana; Garve, Lennart K B; Leonori, Daniele; Aggarwal, Varinder K

    2017-02-13

    Homologation of readily available α-boryl pyrrolidines with metal carbenoids is especially challenging even when good leaving groups (Cl(-) ) are employed. By performing a solvent switch from Et2 O to CHCl3 , efficient 1,2-metalate rearrangement of the intermediate boronate occurs with both halide and ester leaving groups. The methodology was used in the total synthesis of the Stemona alkaloid (-)-stemaphylline in just 11 steps (longest linear sequence), with high stereocontrol (>20:1 d.r.) and 11 % overall yield. The synthesis also features a late-stage lithiation-borylation reaction with a tertiary amine containing carbenoid. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Polyurethane synthesis reactions in asphalts

    Energy Technology Data Exchange (ETDEWEB)

    Bukowski, A.; Gretkiewicz, J.

    1982-04-01

    A series of asphalt-polyurethane composites was prepared by means of polyurethane synthesis in asphalt and carried out in melt. The applied materials were asphalts of differentiated group components content, polyester polyols of chain structure from linear to strongly branched, 2,4-tolylene diisocyanate, 4,4-methylenebis(phenyl isocyanate), and tinorganic catalyst. The asphalt components react with isocyanates to a minimal degree. The influence of the applied substrates, temperature, and polyurethane content in the system on the basic kinetic relations characterizing the process is presented. Polyurethane synthesis in asphalts does not differ in a fundamental way from the obtaining of polyurethanes, especially when their content in the composition is significant, 20 wt% and more.

  8. Synthesis of Polycyclic Natural Products

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Tuan Hoang [Iowa State Univ., Ames, IA (United States)

    2003-01-01

    With the continuous advancements in molecular biology and modern medicine, organic synthesis has become vital to the support and extension of those discoveries. The isolations of new natural products allow for the understanding of their biological activities and therapeutic value. Organic synthesis is employed to aid in the determination of the relationship between structure and function of these natural products. The development of synthetic methodologies in the course of total syntheses is imperative for the expansion of this highly interdisciplinary field of science. In addition to the practical applications of total syntheses, the structural complexity of natural products represents a worthwhile challenge in itself. The pursuit of concise and efficient syntheses of complex molecules is both gratifying and enjoyable.

  9. Hydrothermal Synthesis of Metal Silicates

    Institute of Scientific and Technical Information of China (English)

    Lii Kwang-Hwa

    2004-01-01

    Organically templated metal phosphates have been extensively studied because of interesting structural chemistry and potential applications in catalysis. However, in most cases the organic templates cannot be removed without collapse of the frameworks. This is in contrast to the high thermal stability and extensive applications of zeolites in refinery and petrochemical processes.Therefore, studies have been directed to the synthesis of transition metal silicates to produce more stable frameworks. Our synthetic methods are twofold, namely mild hydrothermal reactions in Teflon-lined autoclaves at 100-200 ℃ using organic amines as templates and high-temperature,high-pressure hydrothermal reactions in gold ampoules contained in a high-pressure reaction vessel at ca. 550 ℃ and 150 Mpa using alkali metal cations as templates. In this presentation I will report the high-temperature, high-pressure hydrothermal synthesis, crystal structures, and solid-state NMR spectroscopy of a number of new silicates of indium, uranium, and transition metals.

  10. Sustainable Process Synthesis-Intensification

    DEFF Research Database (Denmark)

    Babi, Deenesh Kavi; Holtbruegge, Johannes; Lutze, Philip

    2014-01-01

    Sustainable process design can be achieved by performing process synthesis and process intensification together. This approach first defines a design target through a sustainability analysis and then finds design alternatives that match the target through process intensification. A systematic...... concepts and the framework are presented together with the results from a case study highlighting the application of the framework to the sustainable design of a production process for dimethyl carbonate......., multi-stage framework for process synthesis- intensification that identifies more sustainable process designs has been developed. At stages 1-2, the working scale is at the level of unit operations, where a base case design is identified and analyzed with respect to sustainability metrics. At stages 3...

  11. Mechanism Studies of LCP Synthesis

    Directory of Open Access Journals (Sweden)

    Anne Buyle Padias

    2011-05-01

    Full Text Available The LCP (Liquid Crystal Polymer known as Vectra is synthesized by acidolysis of 4-hydroxybenzoic acid with 6-hydroxy-2-naphthoic acid. The apparently simple acidolysis mechanism for LCP polycondensation is in fact a complex blend of mechanisms. Kinetics of model reactions and of actual polycondensations followed second-order kinetics and their rate constants were comparable. In the latter stages, ketene loss leads to phenolic ends, while decarboxylation provides phenyl ester ends. Accordingly, the mechanism changes to phenolysis. A quinone methide intermediate may also intervene, as revealed by kinetics studies and MALDI-TOF spectroscopy. Tailor-made matrices and synthesis of alternating well-defined oligomers assisted our studies. Nucleophilic aromatic substitutions may play a role, and we speculate on possible chain polycondensation. Esterolysis may be a useful alternative to LCP synthesis. Complications caused by ketene loss can be averted by the use of methoxycarbonyloxy monomers.

  12. Synthesis of Polycyclic Natural Products

    Energy Technology Data Exchange (ETDEWEB)

    Tuan Hoang Nguyen

    2003-05-31

    With the continuous advancements in molecular biology and modern medicine, organic synthesis has become vital to the support and extension of those discoveries. The isolations of new natural products allow for the understanding of their biological activities and therapeutic value. Organic synthesis is employed to aid in the determination of the relationship between structure and function of these natural products. The development of synthetic methodologies in the course of total syntheses is imperative for the expansion of this highly interdisciplinary field of science. In addition to the practical applications of total syntheses, the structural complexity of natural products represents a worthwhile challenge in itself. The pursuit of concise and efficient syntheses of complex molecules is both gratifying and enjoyable.

  13. Automatic Synthesis of Multilevel Combinational Logic

    DEFF Research Database (Denmark)

    Andersen, Anders C.; Madsen, Jan; Madsen, J.R.

    1989-01-01

    This paper describes a system for the synthesis of multilevel combinational logic, transforming functional description into mask layout. The system includes a logic synthesis part, partly consisting of tools developed at Eindhoven University of Technology, which has been interfaced to the layout...... synthesis part in the CATOE-system, developed at the DesignCenter of Electronics Institute. The various steps in the transformation are presented together with a complete design example, implementing a multi-output combinational decoder function....

  14. A survey of modal synthesis methods.

    Science.gov (United States)

    Hart, G. C.; Hurty, W. C.; Collins, J. D.

    1971-01-01

    Several modal synthesis procedures for the dynamic analysis of largy composite structural systems are surveyed. The matrix formulation of the free-free modal synthesis procedures is presented. Also given are schematic flow charts of the analysis procedure used in three prominent methods. The advantages and disadvantages of several modal synthesis methods for different classes of structural problems are presented in order to enable the engineer to select the best procedure for his particular type of problem.

  15. Population Synthesis for Mira Variables

    Institute of Scientific and Technical Information of China (English)

    Chun-Hua Zhu; Chao-Zheng Zha

    2005-01-01

    By means of a population synthesis code, we investigate the Mira variables. Their birth rate (over 0.65yr-1) and their number (~ 130000) in the Galaxy are estimated. For all possible Mira variables, ranges of their initial masses,pulsating periods, mass losses and lifetimes are given. We check our model with the observed Mira variables near the Sun and our results prove to be valid.

  16. SOLID PHASE SYNTHESIS OF ISOXAZOLINES

    Institute of Scientific and Technical Information of China (English)

    SUNWeimin; LUOJuntao; 等

    2002-01-01

    The solid-phase synthesis of isoxazolines on 2-polystyrylsulfonamidoethanol resin is reported.2-Polystyrylsulfonamidoethanol resin 1 was reacted with acryloyl chloride to afford 2-polystyrylsulfonylamidoethyl acrylate resin 2,which was further reacted with brominated aldoximes by [3+2] cycloaddition to give isoxazoline resin 4.Resin 4 was treated with aqueous 6 mol/L HCl solution to obtain isoxazolines in good yield and purity.

  17. Synthesis and Modification of Clinoptilolite

    OpenAIRE

    Pavlina Ambrozova; Jindrich Kynicky; Tomas Urubek; Vinh Dinh Nguyen

    2017-01-01

    Clinoptilolite is a natural mineral with exceptional physical characteristics resulting from its special crystal structure, mainstreamed into a large zeolite group called heulandites. An overall view of the research related to the synthesis, modification and application of synthetic clinoptilolite is presented. A single phase of clinoptilolite can be hydrothermally synthesized for 1–10 days in an autoclave from various silica, alumina, and alkali sources with initial Si/Al ratio from 3.0 to 5...

  18. Artificial Intelligence A New Synthesis

    CERN Document Server

    Nilsson, Nils J

    1998-01-01

    Intelligent agents are employed as the central characters in this new introductory text. Beginning with elementary reactive agents, Nilsson gradually increases their cognitive horsepower to illustrate the most important and lasting ideas in AI. Neural networks, genetic programming, computer vision, heuristic search, knowledge representation and reasoning, Bayes networks, planning, and language understanding are each revealed through the growing capabilities of these agents. The book provides a refreshing and motivating new synthesis of the field by one of AI's master expositors and leading re

  19. Synthesis of tritium labelled sparsomycin

    Energy Technology Data Exchange (ETDEWEB)

    Broek, L.A.G.M. van den (Katholieke Univ. Nijmegen (Netherlands)); Willemsen, K.C.M.W.; Schlachter, I.H.G.; Ottenheijm, H.C.J.; Kaspersen, F.M. (Organon International B.V., Oss (Netherlands). Scientific Development Group)

    1989-05-01

    The synthesis is described of tritiated sparsomycin (5), a broad-spectrum antitumor antibiotic, with high specific activity (31.4 Ci/mmol, 1/16 TBq/mmol). The radiolabel was introduced by reduction of the cysteine methyl ester 1 with lithium borotritide, [sup 3]H NMR analysis of the final product showed the concomitant formation of the mono-and ditritiated compound in a ratio of 2:1. (Author).

  20. Multiview synthesis for autostereoscopic displays

    Science.gov (United States)

    Dane, Gökçe.; Bhaskaran, Vasudev

    2013-09-01

    Autostereoscopic (AS) displays spatially multiplex multiple views, providing a more immersive experience by enabling users to view the content from different angles without the need of 3D glasses. Multiple views could be captured from multiple cameras at different orientations, however this could be expensive, time consuming and not applicable to some applications. The goal of multiview synthesis in this paper is to generate multiple views from a stereo image pair and disparity map by using various video processing techniques including depth/disparity map processing, initial view interpolation, inpainting and post-processing. We specifically emphasize the need for disparity processing when there is no depth information is available that is associated with the 2D data and we propose a segmentation based disparity processing algorithm to improve disparity map. Furthermore we extend the texture based 2D inpainting algorithm to 3D and further improve the hole-filling performance of view synthesis. The benefit of each step of the proposed algorithm is demonstrated with comparison to state of the art algorithms in terms of visual quality and PSNR metric. Our system is evaluated in an end-to-end multi view synthesis framework where only stereo image pair is provided as input to the system and 8 views are outputted and displayed in 8-view Alioscopy AS display.

  1. New frontiers in design synthesis

    Science.gov (United States)

    Goldin, D. S.; Venneri, S. L.; Noor, A. K.

    1999-01-01

    The Intelligent Synthesis Environment (ISE), which is one of the major strategic technologies under development at NASA centers and the University of Virginia, is described. One of the major objectives of ISE is to significantly enhance the rapid creation of innovative affordable products and missions. ISE uses a synergistic combination of leading-edge technologies, including high performance computing, high capacity communications and networking, human-centered computing, knowledge-based engineering, computational intelligence, virtual product development, and product information management. The environment will link scientists, design teams, manufacturers, suppliers, and consultants who participate in the mission synthesis as well as in the creation and operation of the aerospace system. It will radically advance the process by which complex science missions are synthesized, and high-tech engineering Systems are designed, manufactured and operated. The five major components critical to ISE are human-centered computing, infrastructure for distributed collaboration, rapid synthesis and simulation tools, life cycle integration and validation, and cultural change in both the engineering and science creative process. The five components and their subelements are described. Related U.S. government programs are outlined and the future impact of ISE on engineering research and education is discussed.

  2. Plasmenylethanolamine synthesis in Leishmania major.

    Science.gov (United States)

    Pawlowic, Mattie C; Hsu, Fong-Fu; Moitra, Samrat; Biyani, Neha; Zhang, Kai

    2016-07-01

    Ethanolamine glycerophospholipids are ubiquitous cell membrane components. Trypanosomatid parasites of the genus Leishmania synthesize the majority of their ethanolamine glycerophospholipids as 1-O-alk-1'-enyl-2-acyl-sn-glycero-3-phosphoethanolamine or plasmenylethanolamine (PME) through the Kennedy pathway. PME is a subtype of ether phospholipids also known as ethanolamine plasmalogen whose functions are not well characterized. In this study, we investigated the role of PME synthesis in Leishmania major through the characterization of an ethanolamine phosphotransferase (EPT) mutant. EPT-null parasites are largely devoid of PME and fully viable in regular medium but fail to proliferate in the absence of fetal bovine serum. They exhibit significant abnormalities in the synthesis and localization of GPI-anchored surface molecules. EPT-null mutants also show attenuated virulence in BALB/c mice. Furthermore, in addition to PME synthesis, ethanolamine also contributes to the production of phosphatidylcholine, the most abundant class of lipids in Leishmania. Together, these findings suggest that ethanolamine production is likely required for Leishmania promastigotes to generate bulk phospholipids, to handle stress, and to control the expression of membrane bound virulence factors. © 2016 John Wiley & Sons Ltd.

  3. Enantioselective Synthesis of (−)-Acetylapoaranotin

    Science.gov (United States)

    2017-01-01

    The first enantioselective total synthesis of the epipolythiodiketopiperazine (ETP) natural product (−)-acetylapoaranotin (3) is reported. The concise synthesis was enabled by an eight-step synthesis of a key cyclohexadienol-containing amino ester building block. The absolute stereochemistry of both amino ester building blocks used in the synthesis is set through catalytic asymmetric (1,3)-dipolar cycloaddition reactions. The formal syntheses of (−)-emethallicin E and (−)-haemotocin are also achieved through the preparation of a symmetric cyclohexadienol-containing diketopiperazine. PMID:28349698

  4. Type synthesis to design variable camber mechanisms

    Directory of Open Access Journals (Sweden)

    Gang Li

    2016-08-01

    Full Text Available This article proposes multiple hinges’ type spectrum that provides an effective description of the multiple hinges of planar kinematic chains. The relationships between characteristic invariants are established and applied into type synthesis methods. A type synthesis method for planar kinematic chains, which is called the characteristic spectrum analysis type synthesis method, is proposed. A systematic design method for variable camber mechanisms is proposed. Using the results of the type synthesis and the systematic design method, three design schemes are proposed and the mathematic models are set up. Some simulation analysis has been done. All these analyses can verify the deformation performance of the proposed mechanism.

  5. Modulation of protein synthesis by polyamines.

    Science.gov (United States)

    Igarashi, Kazuei; Kashiwagi, Keiko

    2015-03-01

    Polyamines are ubiquitous small basic molecules that play important roles in cell growth and viability. Since polyamines mainly exist as a polyamine-RNA complex, we looked for proteins whose synthesis is preferentially stimulated by polyamines at the level of translation, and thus far identified 17 proteins in Escherichia coli and 6 proteins in eukaryotes. The mechanisms of polyamine stimulation of synthesis of these proteins were investigated. In addition, the role of eIF5A, containing hypusine formed from spermidine, on protein synthesis is described. These results clearly indicate that polyamines and eIF5A contribute to cell growth and viability through modulation of protein synthesis.

  6. Solar synthesis: prospects in visible light photocatalysis

    National Research Council Canada - National Science Library

    Schultz, Danielle M; Yoon, Tehshik P

    2014-01-01

    .... Nevertheless, the use of visible light in photochemical synthesis is fundamentally challenging because organic molecules tend not to interact with the wavelengths of visible light that are most...

  7. [Constitutive synthesis of cellulase by Trichoderma lignorum].

    Science.gov (United States)

    Lobanok, A G; Pavlovskaia, Zh I

    1977-01-01

    The induction of cellulase synthesis by lactose was studied in the resting cells of Trichoderma lignorum OM 534. The effect depended on the concentration of lactose, pH, and the age of the mycelium. The induction of the enzyme synthesis by lactose is supressed by glucose and its metabolites. The repression by glucose is partly eliminated by Cyk 3'-5'-AMP, theophylline, and coffeine. The induction of cellulase by lactose is regarded as a derepression of the synthesis of this enzyme as a result of slow assimilation of the disaccharide. The synthesis of cellulase in T. lignorum is presumed to be constitutive.

  8. Synthesis centers as critical research infrastructure

    Science.gov (United States)

    Baron, Jill; Specht, Alison; Garnier, Eric; Bishop, Pamela; Campbell, C. Andrew; Davis, Frank W.; Fady, Bruno; Field, Dawn; Gross, Louis J.; Guru, Siddeswara M.; Halpern, Benjamin S; Hampton, Stephanie E.; Leavitt, Peter R.; Meagher, Thomas R.; Ometto, Jean; Parker, John N.; Price, Richard; Rawson, Casey H.; Rodrigo, Allen; Sheble, Laura A.; Winter, Marten

    2017-01-01

    Demand for the opportunity to participate in a synthesis-center activity has increased in the years since the US National Science Foundation (NSF)–funded National Center for Ecological Analysis and Synthesis (NCEAS) opened its doors in 1995 and as more scientists across a diversity of scientific disciplines have become aware of what synthesis centers provide. The NSF has funded four synthesis centers, and more than a dozen new synthesis centers have been established around the world, some following the NSF model and others following different models suited to their national funding environment (http://synthesis-consortium.org).Scientific synthesis integrates diverse data and knowledge to increase the scope and applicability of results and yield novel insights or explanations within and across disciplines (Pickett et al. 2007, Carpenter et al. 2009). The demand for synthesis comes from the pressing societal need to address grand challenges related to global change and other issues that cut across multiple societal sectors and disciplines and from recognition that substantial added scientific value can be achieved through the synthesis-based analysis of existing data. Demand also comes from groups of scientists who see exciting opportunities to generate new knowledge from interdisciplinary and transdisciplinary collaboration, often capitalizing on the increasingly large volume and variety of available data (Kelling et al. 2009, Bishop et al. 2014, Specht et al. 2015b). The ever-changing nature of societal challenges and the availability of data with which to address them suggest there will be an expanding need for synthesis.However, we are now entering a phase in which government support for some existing synthesis centers has ended or will be ending soon, forcing those centers to close or develop new operational models, approaches, and funding streams. We argue here that synthesis centers play such a unique role in science that continued long-term public

  9. Novel synthesis of substituted benzylidenecyclohexanone by microwave assisted organic synthesis

    Science.gov (United States)

    Handayani, Sri; Budimarwanti, Cornelia; Haryadi, Winarto

    2017-03-01

    Benzylidenecyclohexanone derivatives are compounds with wide bioactivity. Usually, it was synthesized from cyclohexanones and benzaldehyde derivatives under base condition. This research presents a rapid and simple method to synthesis substituted benzylidenecyclohexanone. Cyclohexanone was mixed with 4-hydroxybenzaldehyde in acid condition under MAOS for 2 minutes, then it was left to cooled. Brownish purple powder in 81.47% yield was obtained. The product was identified by gas chromatography, then followed by structure elucidation by using NMR spectrophotometer. The novel compound is confirmed as 4-((E)-((1E,3'E)-3'-(4-hydroxybenzylidene)-2'-oxo-[1,1'-bi(cyclohexylidene)]-2,5-dienylidene-4-ylidene) me-thoxy)benzaldehyde.

  10. SCMC for SLA: A Research Synthesis

    Science.gov (United States)

    Sauro, Shannon

    2011-01-01

    This research synthesis explores the role of synchronous computer-mediated communication (SCMC) for second language acquisition (SLA). Using Hymes' (1971) notion of communicative competence and Canale and Swain's (1980; Canale, 1983) subsequent framework for communicative language teaching, the synthesis examines the research trends, methods, and…

  11. Standardized chemical synthesis of Pseudomonas aeruginosa pyocyanin

    Directory of Open Access Journals (Sweden)

    Rajkumar Cheluvappa

    2014-01-01

    As we have extracted pyocyanin both from P. aeruginosa cultures, and via chemical synthesis; we know the procedural and product-quality differences. We endorse the relative ease, safety, and convenience of using the chemical synthesis described here. Crucially, our “naturally endotoxin-free” pyocyanin can be extracted easily without using infectious bacteria.

  12. The Synthesis and Characterization of Several Corroles

    African Journals Online (AJOL)

    NICO

    Preliminary results towards the synthesis of a corrole-based vitamin B12 analogue are reported. The synthesis of ..... petroleum ether (1:4 v/v) containing 1 % triethylamine; ethyl acetate ... by column chromatography on flash silica gel with ethyl.

  13. Total Synthesis of (±)-Celaphanol A

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The first total synthesis of (±)-Celaphanol A was accomplished starting from α-cyclocitral and 3,4-dimethoxy benzyl chloride via a six-step process, in which the intramolecular cyclization of ketone 4 with BF3@Et2O afforded an all-cis isomer intermediate for synthesis of aromatic tricyclic diterpenes.

  14. The total synthesis of cannabisin G

    Directory of Open Access Journals (Sweden)

    YAMU XIA

    2010-12-01

    Full Text Available A convenient method for the synthesis of lignanamide cannabisin G, starting from vanillin, was developed. The convergent synthesis was based on the Stobbe reaction as C–C bond-forming steps to give the skeleton of lignan, which was condensed with a derivative of tyramine to obtain synthetic cannabisin G for the first time.

  15. Synthesis of a jojoba bean disaccharide.

    Science.gov (United States)

    Kornienko, A; Marnera, G; d'Alarcao, M

    1998-08-01

    A synthesis of the disaccharide recently isolated from jojoba beans, 2-O-alpha-D-galactopyranosyl-D-chiro-inositol, has been achieved. The suitably protected chiro-inositol unit was prepared by an enantiospecific synthesis from L-xylose utilizing SmI2-mediated pinacol coupling as a key step.

  16. Synthesis of melamine-glucose resin adhesive

    Institute of Scientific and Technical Information of China (English)

    CHEN Shuanhu; ZHANG Lei

    2005-01-01

    The synthesis of a novel melamine-glucose adhesive that is similar to urea-formaldehyde adhesive is reported in this paper. The conditions of synthesis, such as the initial pH, the quantity of catalyst, the temperature of reaction, the percentage of each reactant and the time of reaction, were optimized by using the orthogonal experimental method.

  17. Urea synthesis in patients with chronic pancreatitis

    DEFF Research Database (Denmark)

    Hamberg, Ole; Sonne, J; Larsen, S

    2001-01-01

    Up-regulation of urea synthesis by amino acids and dietary protein intake may be impaired in patients with chronic pancreatitis (CP) due to the reduced glucagon secretion. Conversely, urea synthesis may be increased as a result of the chronic inflammation. The aims of the study were to determine...

  18. SCMC for SLA: A Research Synthesis

    Science.gov (United States)

    Sauro, Shannon

    2011-01-01

    This research synthesis explores the role of synchronous computer-mediated communication (SCMC) for second language acquisition (SLA). Using Hymes' (1971) notion of communicative competence and Canale and Swain's (1980; Canale, 1983) subsequent framework for communicative language teaching, the synthesis examines the research trends, methods, and…

  19. Synthesis and Photocatalytic Reactivity of Vinylsulfonium Ylides.

    Science.gov (United States)

    Klose, Immo; Misale, Antonio; Maulide, Nuno

    2016-08-19

    Although sulfur ylides are textbook reagents in organic synthesis, surprisingly little variation of substituents on sulfur is usually observed. In particular, vinylsulfonium ylides have been neglected so far. Herein, we present a study on their synthesis and reactivity, including interesting behavior under photocatalytic conditions.

  20. Design and synthesis of multifunctional phospholipids

    NARCIS (Netherlands)

    Drakopoulou, E; Tsivgoulis, GM; Mukhopadhyay, A; Brisson, A

    2000-01-01

    The synthesis of a bifunctionalized phosholipid capable of binding streptavidin or poly-histidine-tagged proteins is reported for the first time. The head group containing both a biotin and an NTA chelator is synthesized via a new approach using solid phase synthesis. (C) 2000 Elsevier Science Ltd.

  1. Synthesizing Evidence: Synthesis Methods for Evidence Clearinghouses

    Science.gov (United States)

    Valentine, Jeff; Lau, Timothy

    2015-01-01

    Following the theme of the first two presentations, this presentation will focus on the choices available for research synthesis when summarizing research evidence. The presenters will describe the current research synthesis practice of the What Works Clearinghouse (WWC) as well as several alternative models, including inverse-variance weighted…

  2. A concise and stereoselective synthesis of squalamine.

    Science.gov (United States)

    Zhang, Dong-Hui; Cai, Feng; Zhou, Xiang-Dong; Zhou, Wei-Shan

    2003-09-04

    [reaction: see text] A short and highly stereoselective synthesis of the novel steroid squalamine (1) was accomplished in nine steps from easily available methyl chenodeoxylcholanate 2. Our synthesis featured improved dehydrogenation of 4 followed by conjugate reduction to construct the trans AB-ring system and efficient asymmetric isopropylation of aldehyde 6 to introduce the C-24R-hydroxyl group.

  3. Synthesis and antimicrobial activity of squalamine analogue.

    Science.gov (United States)

    Kim, H S; Choi, B S; Kwon, K C; Lee, S O; Kwak, H J; Lee, C H

    2000-08-01

    Synthesis and antimicrobial activity of squalamine analogue 2 are reported. The synthesis of 2 was accomplished from bisnoralcohol 3. The spermidine moiety was introduced via reductive amination of an appropriately functionalized 3beta-aminosterol with spermidinyl aldehyde 17 utilizing sodium triacetoxyborohydride as the reducing agent. Compound 2 shows weaker antimicrobial activity than squalamine.

  4. Novel Synthesis of Aluminium Oxide Nanofibers

    Science.gov (United States)

    2001-11-01

    UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP012177 TITLE: Novel Synthesis of Aluminium Oxide Nanofibers DISTRIBUTION...ADP012174 thru ADP012259 UNCLASSIFIED Mat. Res. Soc. Symp. Proc. Vol. 703 © 2002 Materials Research Society V1.8 Novel Synthesis of Aluminium Oxide Nanofibers

  5. Providing Guided Practice in Discourse Synthesis

    Science.gov (United States)

    Numrich, Carol; Kennedy, Alan S.

    2017-01-01

    In this article, the authors discuss the importance of the skill of synthesis in university-level writing. They outline specific challenges faced by students of English as a second language with synthesis as a writing skill. They then describe a lesson that they created for an English for academic purposes class for graduate students in the field…

  6. Lactobacillus assisted synthesis of titanium nanoparticles

    Science.gov (United States)

    Prasad, K.; Jha, Anal K.; Kulkarni, A. R.

    2007-05-01

    An eco-friendly lactobacillus sp. (microbe) assisted synthesis of titanium nanoparticles is reported. The synthesis is performed at room temperature. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of Ti nanoparticles. Individual nanoparticles as well as a number of aggregates almost spherical in shape having a size of 40 60 nm are found.

  7. Web-Mediated Knowledge Synthesis for Educators

    Science.gov (United States)

    DeSchryver, Michael

    2015-01-01

    Ubiquitous and instant access to information on the Web is challenging what constitutes 21st century literacies. This article explores the notion of Web-mediated knowledge synthesis, an approach to integrating Web-based learning that may result in generative synthesis of ideas. This article describes the skills and strategies that may support…

  8. Accelerate synthesis in ecology and environmental sciences

    Science.gov (United States)

    Synthesis of diverse knowledge is a central part of all sciences, but especially those such as ecology and environmental sciences which draw information from many disciplines. Research and education in ecology are intrinsically synthetic, and synthesis is increasingly needed to find solutions for en...

  9. Heteropolyacids in synthesis of benzoyl hydrazone derivatives

    Directory of Open Access Journals (Sweden)

    Sodeh Sadjadi

    2009-12-01

    Full Text Available Keggin type of heteropolyacids as green reusable and efficient catalyst was used in the synthesis of benzoyl hydrazones from reaction of benzoic acid hydrazide and aldehyde and ketone derivatives. The synthesis of N-acetyl and N-benzoyl derivatives has also been performed by the reaction of obtained benzoyl hydrazones with acylcholorides in presence of this kind of heteropolyacids.

  10. A modified total synthesis of cystothiazole A

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A modified total synthesis of cystothiazole A is described. In this synthetic strategy, a one-step transformation of acylated oxazolidinone to β-ketoester has been successfully applied, thus making the synthetic route more efficient. This method may also be potentially applied in synthesis of other related β-substituted-β-methoxyl acrylates (bb-MOAs).

  11. A modified total synthesis of cystothiazole A

    Institute of Scientific and Technical Information of China (English)

    BAI YueXia; BAO JiLai; REN Jun; WANG ZhongWen

    2009-01-01

    A modified total synthesis of cystothiazole A is described.In this synthetic strategy,a one-step transformation of acylated oxazolidinone to β-ketoester has been successfully applied,thus making the synthetic route more efficient.This method may also be potentially applied in synthesis of other related β-substituted-β-methoxyl acrylates (bb-MOAs).

  12. HMM Adaptation for child speech synthesis

    CSIR Research Space (South Africa)

    Govender, Avashna

    2015-09-01

    Full Text Available Hidden Markov Model (HMM)-based synthesis in combination with speaker adaptation has proven to be an approach that is well-suited for child speech synthesis. This paper describes the development and evaluation of different HMM-based child speech...

  13. Microwave Hydrothermal Synthesis PZT of Nanometer Crystal

    Institute of Scientific and Technical Information of China (English)

    Hongxing LIU; Hong DENG; Yan LI; Yanrong LI

    2004-01-01

    It was focused on the applications and developments of microwave hydrothermal synthesis piezoelectric ceramic powder. The microwave hydrothermal vessel was designed and manufactured. The microwave hydrothermal synthesis system was established and the PZT piezoelectric ceramic powder was synthesized. XRD and TEM have been used to characterize the products in detail. The diameter of the PZT powder particle is from 40 to 60 nm.

  14. Synthesis of benzofurans from oxygenated phenoxyamines

    Energy Technology Data Exchange (ETDEWEB)

    Castellino, A.J.; Rapoport, H.

    1984-11-16

    O-Aryloximes having various oxygenated substitution patterns have been converted to benzofurans, with implications toward natural product synthesis, through an extension of the Fischer indole type of synthesis. The effect of the substituent pattern in the benzene ring and the nature of the carbonyl derived portion of the oxime on benzofuranization were explored. 11 references, 4 tables.

  15. Astrobiology - The New Synthesis

    Science.gov (United States)

    Sik, A.; Simon, T.

    á vált sötétebb helyekre való költöztetése: mélyen a föld alá helyezik, a forró vulkáni kőzetek hasadékaiba, ahol bőségesen találhatott magának ként, vasat, hidrogént és szenet. A genetikai bizonyítékok alapján a hő- és mélységkedvelők es- 4 nek legközelebb az egyetemes őshöz. [16]. The synthesis Mindezek alapján a földi extremofilek vizsgálata során deríthetjük ki, hogy más égitesteken (egyelőre a Naprendszerben) hol kell keresnünk az életet, és mit kell keresnünk a planetológiai kutatások során egyre jobban megismert szélsőséges környezetekben. Segítségükkel megtudhatjuk, melyek azok az alak- tani, geokémiai, esetleg biokémiai jegyek, amelyek életre utalhatnak; melyek az élet azon alapvető jellemzői, amelyek elég általánosak és biztonsággal kimu- tathatók, milyen műszerekkel kell felszerelnünk a jövő űrszondáit, milyen módszereket kell alkalmaznunk, hogy sikerrel kutathassunk a Földön kívüli élet után. References [1] H. Hargitai et. al., XXXIII. LPSC (2002), Houston, #1261; [2] Origins Roadmap, 2000, JPL; [3] http://www.obspm.fr/encycl/catalog.html [4] http://www.physics.sfsu.edu/~gmarcy/planetsearch/ upsand/upsand.html [5] http://tpf.jpl.nasa.gov/ [6] A. Kereszturi, and A. Sik, XXXI. LPSC (2000), Houston, #1216; [7] S. W. Squyres et. al. (1992) in H. H. Kieffer, et. al.: Mars, University of Arizona Press, Tucson, 523-554; [8] http://www.jpl.nasa.gov/europaorbiter/ [9] www.nineplanets.org [10] http://www.jpl.nasa.gov/cassini/ [11] http://www- curator.jsc.nasa.gov/curator/antmet/ marsmets/alh84001/sample.htm [12] P. Davies: The fifth miracle - The search for the origin of life (1998), Orion; [13] M. T. Madigan and B. L. Marrs: Extremophiles, Scientific American (1997), 276, 82-87; [14] J. A. Lake et al.: Methanococcus Genome, Science (1996), 274, 901-905; [15] N. C. Kyrpides and G. J. Olsen: Archaeal and bacterial hyperthermophiles: Horizontal gene exchange or common ancestry?, Trends in

  16. Synthesis of nanoparticles and nanomaterials biological approaches

    CERN Document Server

    Abdullaeva, Zhypargul

    2017-01-01

    This book covers biological synthesis approaches for nanomaterials and nanoparticles, including introductory material on their structure, phase compositions and morphology, nanomaterials chemical, physical, and biological properties. The chapters of this book describe in sequence the synthesis of various nanoparticles by microorganisms, bacteria, yeast, algae, and actynomycetes; plant and plant extract-based synthesis; and green synthesis methods. Each chapter provides basic knowledge on the synthesis of nanomaterials, defines fundamental terms, and aims to build a solid foundation of knowledge, followed by explanations, examples, visual photographs, schemes, tables and illustrations. Each chapter also contains control questions, problem drills, as well as case studies that clarify theory and the explanations given in the text. This book is ideal for researchers and advanced graduate students in materials engineering, biotechnology, and nanotechnology fields. As a reference book this work is also appropriate ...

  17. Protein chemical synthesis in drug discovery.

    Science.gov (United States)

    Liu, Fa; Mayer, John P

    2015-01-01

    The discovery of novel therapeutics to combat human disease has traditionally been among the most important goals of research chemists. After a century of innovation, state-of-the-art chemical protein synthesis is now capable of efficiently assembling proteins of up to several hundred residues in length from individual amino acids. By virtue of its unique ability to incorporate non-native structural elements, chemical protein synthesis has been seminal in the recent development of several novel drug discovery technologies. In this chapter, we review the key advances in peptide and protein chemistry which have enabled our current synthetic capabilities. We also discuss the synthesis of D-proteins and their applications in mirror image phage-display and racemic protein crystallography, the synthesis of enzymes for structure-based drug discovery, and the direct synthesis of homogenous protein pharmaceuticals.

  18. Small Molecule Library Synthesis Using Segmented Flow

    Directory of Open Access Journals (Sweden)

    Christina M. Thompson

    2011-11-01

    Full Text Available Flow chemistry has gained considerable recognition as a simple, efficient, and safe technology for the synthesis of many types of organic and inorganic molecules ranging in scope from large complex natural products to silicon nanoparticles. In this paper we describe a method that adapts flow chemistry to the synthesis of libraries of compounds using a fluorous immiscible solvent as a spacer between reactions. The methodology was validated in the synthesis of two small heterocycle containing libraries. The reactions were performed on a 0.2 mmol scale, enabling tens of milligrams of material to be generated in a single 200 mL reaction plug. The methodology allowed library synthesis in half the time of conventional microwave synthesis while maintaining similar yields. The ability to perform multiple, potentially unrelated reactions in a single run is ideal for making small quantities of many different compounds quickly and efficiently.

  19. Depth-optimized reversible circuit synthesis

    Science.gov (United States)

    Arabzadeh, Mona; Saheb Zamani, Morteza; Sedighi, Mehdi; Saeedi, Mehdi

    2013-04-01

    In this paper, simultaneous reduction of circuit depth and synthesis cost of reversible circuits in quantum technologies with limited interaction is addressed. We developed a cycle-based synthesis algorithm which uses negative controls and limited distance between gate lines. To improve circuit depth, a new parallel structure is introduced in which before synthesis a set of disjoint cycles are extracted from the input specification and distributed into some subsets. The cycles of each subset are synthesized independently on different sets of ancillae. Accordingly, each disjoint set can be synthesized by different synthesis methods. Our analysis shows that the best worst-case synthesis cost of reversible circuits in the linear nearest neighbor architecture is improved by the proposed approach. Our experimental results reveal the effectiveness of the proposed approach to reduce cost and circuit depth for several benchmarks.

  20. System Synthesis for Networks of Programmable Blocks

    CERN Document Server

    Mannion, Ryan; Cotterell, Susan; Vahid, Frank

    2011-01-01

    The advent of sensor networks presents untapped opportunities for synthesis. We examine the problem of synthesis of behavioral specifications into networks of programmable sensor blocks. The particular behavioral specification we consider is an intuitive user-created network diagram of sensor blocks, each block having a pre-defined combinational or sequential behavior. We synthesize this specification to a new network that utilizes a minimum number of programmable blocks in place of the pre-defined blocks, thus reducing network size and hence network cost and power. We focus on the main task of this synthesis problem, namely partitioning pre-defined blocks onto a minimum number of programmable blocks, introducing the efficient but effective PareDown decomposition algorithm for the task. We describe the synthesis and simulation tools we developed. We provide results showing excellent network size reductions through such synthesis, and significant speedups of our algorithm over exhaustive search while obtaining...

  1. Assessment of structural diversity in combinatorial synthesis.

    Science.gov (United States)

    Fergus, Suzanne; Bender, Andreas; Spring, David R

    2005-06-01

    This article covers the combinatorial synthesis of small molecules with maximal structural diversity to generate a collection of pure compounds that are attractive for lead generation in a phenotypic, high-throughput screening approach. Nature synthesises diverse small molecules, but there are disadvantages with using natural product sources. The efficient chemical synthesis of structural diversity (and complexity) is the aim of diversity-oriented synthesis, and recent progress is reviewed. Specific highlights include a discussion of strategies to obtain structural diversity and an analysis of molecular descriptors used to classify compounds. The assessment of how successful one synthesis is versus another is subjective, therefore we test-drive software to assess structural diversity in combinatorial synthesis, which is freely available via a web interface.

  2. Feature-aware natural texture synthesis

    KAUST Repository

    Wu, Fuzhang

    2014-12-04

    This article presents a framework for natural texture synthesis and processing. This framework is motivated by the observation that given examples captured in natural scene, texture synthesis addresses a critical problem, namely, that synthesis quality can be affected adversely if the texture elements in an example display spatially varied patterns, such as perspective distortion, the composition of different sub-textures, and variations in global color pattern as a result of complex illumination. This issue is common in natural textures and is a fundamental challenge for previously developed methods. Thus, we address it from a feature point of view and propose a feature-aware approach to synthesize natural textures. The synthesis process is guided by a feature map that represents the visual characteristics of the input texture. Moreover, we present a novel adaptive initialization algorithm that can effectively avoid the repeat and verbatim copying artifacts. Our approach improves texture synthesis in many images that cannot be handled effectively with traditional technologies.

  3. Combustion synthesis of advanced composite materials

    Science.gov (United States)

    Moore, John J.

    1993-01-01

    Self-propagating high temperature (combustion) synthesis (SHS), has been investigated as a means of producing both dense and expanded (foamed) ceramic and ceramic-metal composites, ceramic powders and whiskers. Several model exothermic combustion synthesis reactions were used to establish the importance of certain reaction parameters, e.g., stoichiometry, green density, combustion mode, particle size, etc. on the control of the synthesis reaction, product morphology and properties. The use of an in situ liquid infiltration technique and the effect of varying the reactants and their stoichiometry to provide a range of reactant and product species i.e., solids, liquids and gases, with varying physical properties e.g., volatility and thermal conductivity, on the microstructure and morphology of synthesized composite materials is discussed. Conducting the combustion synthesis reaction in a reactive gas environment to take advantage of the synergistic effects of combustion synthesis and vapor phase transport is also examined.

  4. Lithium synthesis in microquasar accretion.

    Science.gov (United States)

    Iocco, Fabio; Pato, Miguel

    2012-07-13

    We study the synthesis of lithium isotopes in the hot tori formed around stellar mass black holes by accretion of the companion star. We find that sizable amounts of both stable isotopes 6Li and 7Li can be produced, the exact figures varying with the characteristics of the torus and reaching as much as 10(-2) M⊙ for each isotope. This mass output is enough to contaminate the entire Galaxy at a level comparable with the original, pregalactic amount of lithium and to overcome other sources such as cosmic-ray spallation or stellar nucleosynthesis.

  5. New synthesis of. beta. -lactams

    Energy Technology Data Exchange (ETDEWEB)

    Wong, P.K.; Madhavarao, M.; Marten, D.F.; Rosenblum, M.M.

    1977-04-13

    The authors recently reported the regiospecific addition of heteroatomic nucleophiles to a number of Fp(olefin) cations (Fp = eta/sup 5/-C/sub 5/H/sub 5/Fe(CO)/sub 2/). Furthermore, it has been shown that oxidatively induced ligand transfer in FpR complexes (R-Fe-CO ..-->.. FeCOR) leads to carboxylation of R with retention of configuration at the migrating carbon center. It is now shown that an appropriate combination of these processes provides a facile and stereospecific synthesis of mono- and bicyclic ..beta..-lactams from olefins.

  6. Synthesis of (±)-kigelin

    OpenAIRE

    SAEED, Aamer; Ehsan,Somia

    2005-01-01

    A simple synthesis of racemic 8-hydroxy-6,7-dimethoxy-3-methyl-3,4-dihydroisocoumarin or kigelin, a metabolite of Aspergillus terreus and Kigelia pinnata, exhibiting several bioactivities, is described. 3,4,5-Trimethoxyhomophthalic acid was refluxed with acetic anhydride in dry pyridine to afford 2,3,4-trimethoxy-6-(2-oxopropyl)benzoic acid. Reduction of the latter followed by cyclodehydration yielded 6,7,8-trimethoxy-3-methyl-3,4-dihydroisocoumarin which on regioselective demethylation furni...

  7. Cellulose Synthesis in Agrobacterium tumefaciens

    Energy Technology Data Exchange (ETDEWEB)

    Alan R. White; Ann G. Matthysse

    2004-07-31

    We have cloned the celC gene and its homologue from E. coli, yhjM, in an expression vector and expressed the both genes in E. coli; we have determined that the YhjM protein is able to complement in vitro cellulose synthesis by extracts of A. tumefaciens celC mutants, we have purified the YhjM protein product and are currently examining its enzymatic activity; we have examined whole cell extracts of CelC and various other cellulose mutants and wild type bacteria for the presence of cellulose oligomers and cellulose; we have examined the ability of extracts of wild type and cellulose mutants including CelC to incorporate UDP-14C-glucose into cellulose and into water-soluble, ethanol-insoluble oligosaccharides; we have made mutants which synthesize greater amounts of cellulose than the wild type; and we have examined the role of cellulose in the formation of biofilms by A. tumefaciens. In addition we have examined the ability of a putative cellulose synthase gene from the tunicate Ciona savignyi to complement an A. tumefaciens celA mutant. The greatest difference between our knowledge of bacterial cellulose synthesis when we started this project and current knowledge is that in 1999 when we wrote the original grant very few bacteria were known to synthesize cellulose and genes involved in this synthesis were sequenced only from Acetobacter species, A. tumefaciens and Rhizobium leguminosarum. Currently many bacteria are known to synthesize cellulose and genes that may be involved have been sequenced from more than 10 species of bacteria. This additional information has raised the possibility of attempting to use genes from one bacterium to complement mutants in another bacterium. This will enable us to examine the question of which genes are responsible for the three dimensional structure of cellulose (since this differs among bacterial species) and also to examine the interactions between the various proteins required for cellulose synthesis. We have carried out one

  8. The synthesis paradigm in genetics.

    Science.gov (United States)

    Rice, William R

    2014-02-01

    Experimental genetics with model organisms and mathematically explicit genetic theory are generally considered to be the major paradigms by which progress in genetics is achieved. Here I argue that this view is incomplete and that pivotal advances in genetics--and other fields of biology--are also made by synthesizing disparate threads of extant information rather than generating new information from experiments or formal theory. Because of the explosive expansion of information in numerous "-omics" data banks, and the fragmentation of genetics into numerous subdisciplines, the importance of the synthesis paradigm will likely expand with time.

  9. Automated synthesis of sialylated oligosaccharides

    Directory of Open Access Journals (Sweden)

    Davide Esposito

    2012-09-01

    Full Text Available Sialic acid-containing glycans play a major role in cell-surface interactions with external partners such as cells and viruses. Straightforward access to sialosides is required in order to study their biological functions on a molecular level. Here, automated oligosaccharide synthesis was used to facilitate the preparation of this class of biomolecules. Our strategy relies on novel sialyl α-(2→3 and α-(2→6 galactosyl imidates, which, used in combination with the automated platform, provided rapid access to a small library of conjugation-ready sialosides of biological relevance.

  10. EXOPOLYSACCHARIDES SYNTHESIS ON INDUSTRIAL WASTES

    Directory of Open Access Journals (Sweden)

    T.P.

    2016-04-01

    Full Text Available Data from the literature and our own studies on the synthesis of microbial exopolysaccharides on various industrial waste (food industry, agricultural sector, biodiesel production, etc. are reviewed here. Utilization of industrial waste to obtain exopolysaccharides will solve not only the problem of secondary raw materials accumulation, but also will reduce the costs of the biosynthesis of practically valuable metabolites. In addition, some kinds of waste have a number of advantages compared to traditional carbohydrate substrates: aside from environmental health benefits, there are technological ones, like the presence of growth factors. There is also no need to use anti-foam substances and substrate sterilization in the latter case.

  11. Synthesis of new nanocrystal materials

    Science.gov (United States)

    Hassan, Yasser Hassan Abd El-Fattah

    Colloidal semiconductor nanocrystals (NCs) have sparked great excitement in the scientific community in last two decades. NCs are useful for both fundamental research and technical applications in various fields owing to their size and shape-dependent properties and their potentially inexpensive and excellent chemical processability. These NCs are versatile fluorescence probes with unique optical properties, including tunable luminescence, high extinction coefficient, broad absorption with narrow photoluminescence, and photobleaching resistance. In the past few years, a lot of attention has been given to nanotechnology based on using these materials as building blocks to design light harvesting assemblies. For instant, the pioneering applications of NCs are light-emitting diodes, lasers, and photovoltaic devices. Synthesis of the colloidal stable semiconductor NCs using the wet method of the pyrolysis of organometallic and chalcogenide precursors, known as hot-injection approach, is the chart-topping preparation method in term of high quality and monodisperse sized NCs. The advancement in the synthesis of these artificial materials is the core step toward their applications in a broad range of technologies. This dissertation focuses on exploring various innovative and novel synthetic methods of different types of colloidal nanocrystals, both inorganic semiconductors NCs, also known as quantum dots (QDs), and organic-inorganic metal halide-perovskite materials, known as perovskites. The work presented in this thesis focuses on pursuing fundamental understanding of the synthesis, material properties, photophysics, and spectroscopy of these nanostructured semiconductor materials. This thesis contains 6 chapters and conclusions. Chapters 1?3 focus on introducing theories and background of the materials being synthesized in the thesis. Chapter 4 demonstrates our synthesis of colloidal linker--free TiO2/CdSe NRs heterostructures with CdSe QDs grown in the presence of Ti

  12. Combinatorial synthesis of natural products

    DEFF Research Database (Denmark)

    Nielsen, John

    2002-01-01

    for preparation of combinatorial libraries. In other examples, natural products or intermediates have served as building blocks or scaffolds in the synthesis of complex natural products, bioactive analogues or designed hybrid molecules. Finally, structural motifs from the biologically active parent molecule have......Combinatorial syntheses allow production of compound libraries in an expeditious and organized manner immediately applicable for high-throughput screening. Natural products possess a pedigree to justify quality and appreciation in drug discovery and development. Currently, we are seeing a rapid...

  13. Ibuprofen: Synthesis, production and properties

    Directory of Open Access Journals (Sweden)

    Mijin Dušan Ž.

    2003-01-01

    Full Text Available Since its introduction in 1969, ibuprofen has become one of the most common painkillers in the world. Ibuprofen in an NSAID (non-steroidal anti-inflammatory drug and like other drugs of its class it possesses analgetic, antipyretic and anti-inflammatory properties. While ibuprofen is a relatively simple molecule, there is still sufficient structural complexity to ensure that a large number of different synthetic approaches are possible. Since the introduction of pharmaceutical products containing ibuprofen, industrial and academic scientists have developed many potential production processes. This paper describes the history, synthesis and production, as well as the properties and stability of ibuprofen.

  14. Verified OS Interface Code Synthesis

    Science.gov (United States)

    2016-12-01

    5c.  PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Gerwin Klein, Toby Murray 5d.  PROJECT NUMBER 5e.  TASK NUMBER 5f.  WORK UNIT NUMBER 7. PERFORMING...llisapi.dll Verified OS Interface Code Synthesis Final Report for AFOSR AOARD Grant FA2386-14-1-4093 Gerwin Klein, Ramana Kumar, Toby Murray gerwin.klein... Murray t +61 2 8306 0550 e gerwin.klein@data61.csiro.au w trustworthy.systems DISTRIBUTION A. Approved for public release: distribution unlimited.

  15. Synthesis of deuterium labelled lorazepam

    Energy Technology Data Exchange (ETDEWEB)

    Koeves, G.J. (Centre of Forensic Sciences, Toronto, ON (Canada))

    1991-01-01

    Synthesis of {sup 2}H{sub 3}-lorazepam was achieved by modification of literature procedures for the unlabelled drug. The key step in the seven step procedure was the initial one where upon selective exchange of 2-amino-5,2'-dichloro-benzophenone was obtained in deuterated acids. Purifications were carried out by preparative HPLC. The {sup 2}H{sub 3}-lorazepam is suitable for use as an internal standard in GC-MS-NICI-SIM quantitative analysis in forensic case work. (author).

  16. Stereoselective Total Synthesis of Mycalamides

    Institute of Scientific and Technical Information of China (English)

    Masahiro Toyota

    2005-01-01

    @@ 1Introduction Mycalamides A (1a) and B (1b) are potent antiviral compounds from a New Zealand sponge of the genus Mycale. Apart from their antitumor property, mycalamide A (1a) exhibits immunosuppressive action by blocking T-cell activation in mice and is significantly more potent than FK-506 and cyclosporine A. Because of their intriguing biological activity, unique structures and scarce supply of these natural products, mycalamides A (1a) and B (1b) have attracted considerable attention as target molecules for total synthesis, and total, formal, or partial syntheses of this family of compounds have been reported[1,2].

  17. Synthesis of elusive chloropnictenium ions.

    Science.gov (United States)

    Hering-Junghans, Christian; Thomas, Max; Villinger, Alexander; Schulz, Axel

    2015-04-27

    This work describes the synthesis and full characterization of elusive chloropnictenium ion salts of the type [(R)Ar*N(SiMe)ECl][A] ((R)Ar* = 2,6-(CHPh2)-4-R-C6H2, R = Me, tBu; E = Sb, Bi; A(-) = GaCl4, Al(OCH(CF3)2)4). In these species the cation is significantly stabilized by weak arene interactions to flanking phenyl groups of the (R)Ar* moiety. In this context the bonding situation has been studied by computational means and the reactivity towards the Lewis base 4-dimethylaminopyridine (dmap) was investigated.

  18. The total synthesis of (-)-nitidasin.

    Science.gov (United States)

    Hog, Daniel T; Huber, Florian M E; Mayer, Peter; Trauner, Dirk

    2014-08-01

    Nitidasin is a pentacyclic sesterterpenoid with a rare 5-8-6-5 carbon skeleton that was isolated from the Peruvian folk medicine "Hercampuri". It belongs to a small class of sesterterpenoids that feature an isopropyl trans-hydrindane moiety fused to a variety of other ring systems. As a first installment of our general approach toward these natural products, we report the total synthesis of the title compound. Our stereoselective, convergent route involves the addition of a complex alkenyl lithium compound to a trans-hydrindanone, followed by chemoselective epoxidation, ring-closing olefin metathesis, and redox adjustment.

  19. Microwave Plasma Synthesis of Nanopowders

    Institute of Scientific and Technical Information of China (English)

    Joseph; Lik; Hang; Chau

    2007-01-01

    1 Results and Discussion Nanopowders were synthesized by using microwave plasma synthesis technique.The microwave plasma was operated in atmospheric pressure at a frequency of 2.45 GHz.The reaction temperature is directly related to the power of the microwave generator that can be controlled by adjusting the actual operating current.Firstly,ionization and dissociation of precursor species will be occurred in the plasma,nucleus can then be formed by the collision of these molecules,followed by the growth...

  20. Computer Music Synthesis and Composition

    Science.gov (United States)

    Ayers, Lydia

    What is computer music composition? Composers are using the computer for everything from MIDI instruments communicating with computer sequencers, pitch trackers analyzing the sounds of acoustic instruments and converting them to pitch information, live performers with recorded music, performers with interactive computer programs, computer music produced by dancers using sensors, automatic music composition with the computer programs composing the music, composing with sounds or parts of sounds rather than notes, how to structure the use of time, composing with timbres, or the colors of sounds, and timbre morphing, such as a gong morphing to a voice, composing with textures and texture morphing, such as fluttertonguing morphing to pitch, granular synthesis, trills and convolution.

  1. Indenylmetal Catalysis in Organic Synthesis.

    Science.gov (United States)

    Trost, Barry M; Ryan, Michael C

    2017-03-06

    Synthetic organic chemists have a long-standing appreciation for transition metal cyclopentadienyl complexes, of which many have been used as catalysts for organic transformations. Much less well known are the contributions of the benzo-fused relative of the cyclopentadienyl ligand, the indenyl ligand, whose unique properties have in many cases imparted differential reactivity in catalytic processes toward the synthesis of small molecules. In this Review, we present examples of indenylmetal complexes in catalysis and compare their reactivity to their cyclopentadienyl analogues, wherever possible. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Frontiers and Approaches to Chemical Synthesis of Oligodeoxyribonucleotides

    OpenAIRE

    2013-01-01

    The advantages and disadvantages of existing approaches to the synthesis of oligodeoxyribonucleotides (ODN) are discussed focusing on large-scale methods. The liquid phase and solid supported synthesis and the synthesis on soluble polymers are discussed. Different problems concerning the methods and implementation of the ODN synthesis are outlined depending on goals of using target oligomers.

  3. RPython high-level synthesis

    Science.gov (United States)

    Cieszewski, Radoslaw; Linczuk, Maciej

    2016-09-01

    The development of FPGA technology and the increasing complexity of applications in recent decades have forced compilers to move to higher abstraction levels. Compilers interprets an algorithmic description of a desired behavior written in High-Level Languages (HLLs) and translate it to Hardware Description Languages (HDLs). This paper presents a RPython based High-Level synthesis (HLS) compiler. The compiler get the configuration parameters and map RPython program to VHDL. Then, VHDL code can be used to program FPGA chips. In comparison of other technologies usage, FPGAs have the potential to achieve far greater performance than software as a result of omitting the fetch-decode-execute operations of General Purpose Processors (GPUs), and introduce more parallel computation. This can be exploited by utilizing many resources at the same time. Creating parallel algorithms computed with FPGAs in pure HDL is difficult and time consuming. Implementation time can be greatly reduced with High-Level Synthesis compiler. This article describes design methodologies and tools, implementation and first results of created VHDL backend for RPython compiler.

  4. Protein synthesis regulation by leucine

    Directory of Open Access Journals (Sweden)

    Daiana Vianna

    2010-03-01

    Full Text Available In vivo and in vitro studies have demonstrated that high protein diets affect both protein synthesis and regulation of several cellular processes. The role of amino acids as substrate for protein synthesis has been established in the literature. However, the mechanism by which these amino acids modulate transcription and regulate the mRNA translation via mTOR-dependent signaling pathway has yet to be fully determined. It has been verified that mTOR is a protein responsible for activating a cascade of biochemical intracellular events which result in the activation of the protein translation process. Of the aminoacids, leucine is the most effective in stimulating protein synthesis and reducing proteolysis. Therefore, it promotes a positive nitrogen balance, possibly by favoring the activation of this protein. This amino acid also directly and indirectly stimulates the synthesis and secretion of insulin, enhancing its anabolic cellular effects. Therefore, this review aimed to identify the role of leucine in protein synthesis modulation and to discuss the metabolic aspects related to this aminoacid.Estudos in vivo e in vitro verificaram que dietas hiperprotéicas influenciam a síntese protéica e regulam vários processos celulares. O papel dos aminoácidos como substrato para a síntese de proteínas já está bem evidenciado na literatura, porém as formas como esses aminoácidos modulam a etapa da transcrição e regulam a tradução do RNAm, pela via de sinalização dependente da mTOR, ainda não estão totalmente esclarecidas. Tem-se verificado que a mTOR é uma proteína responsável por ativar uma cascata de eventos bioquímicos intracelulares que culminam na ativação do processo de tradução protéica. Dentre todos os aminoácidos, a leucina é a mais eficaz em estimular a síntese protéica, reduzir a proteólise e, portanto, favorecer o balanço nitrogenado positivo, possivelmente por favorecer a ativação desta proteína. Al

  5. Abiogenic synthesis on terrestrial orbit

    Science.gov (United States)

    Simakov, Michael B.; Kuzicheva, Evgenia; Gontareva, Natalia

    Meteorites probably played a central role in the evolution of life. Due to the structure, they tend to adsorb organic compounds and catalyze a variety of organic reactions critical to scenarios of life’s origins. We have shown experimentally that extraterrestrial minerals can catalyze the formation of peptides and nucleotides. The present study was performed onboard different Russian space stations (BION, COSMOS, and MIR) with various duration, altitude, and radiation conditions. Irradiation of solid samples, free or admixed with certain minerals, was the major task of future space flight experiments, planned for performing onboard Russian space satellite Bion-M. The «simulated space ice conditions» experiments have shown the synthesis of simple biochemical compounds in the form of amino acid’s precursors and pyrimidine bases (uracil, cyrosine and thymine) of the nucleic acids. Our investigation dealt with further reaction of nucleic acid components to nucleotides - main components of RNA and DNA, and single aminoacids to oligopeptides. We investigated two types of reactions: (1) abiogenic synthesis of nucleotides from mixtures of nucleoside + inorganic phosphate; (2) abiogenic synthesis of dipeptides from mixtures of simple amino acids. The reaction mixture in the form of a solid film contains (1) nucleoside and dihydrogen phosphate; (2) two different amino acids. Seven different nucleosides (thymidine, cytidine, uracil, adenosine or deoxyadenosine, guanosine or deoxyguanosine) and four mixtures of aromatic (tyrosine or triptophan) and aliphatic (glycine or alanine) amino acids were investigated. Mixtures were irradiated as solid films with different sources of energy: (1) VUV-light of 145 nm; (2) high energy protons (2-6 MeV); and (3) were installed on the surface of biosputnik in outstanding container when they were exposed to the action of all spectra of the open space energy sources during the entire time of flight. We have shown experimentally that the

  6. Bioinspired synthesis of magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    David, Anand [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    The synthesis of magnetic nanoparticles has long been an area of active research. Magnetic nanoparticles can be used in a wide variety of applications such as magnetic inks, magnetic memory devices, drug delivery, magnetic resonance imaging (MRI) contrast agents, and pathogen detection in foods. In applications such as MRI, particle uniformity is particularly crucial, as is the magnetic response of the particles. Uniform magnetic particles with good magnetic properties are therefore required. One particularly effective technique for synthesizing nanoparticles involves biomineralization, which is a naturally occurring process that can produce highly complex nanostructures. Also, the technique involves mild conditions (ambient temperature and close to neutral pH) that make this approach suitable for a wide variety of materials. The term 'bioinspired' is important because biomineralization research is inspired by the naturally occurring process, which occurs in certain microorganisms called 'magnetotactic bacteria'. Magnetotactic bacteria use biomineralization proteins to produce magnetite crystals having very good uniformity in size and morphology. The bacteria use these magnetic particles to navigate according to external magnetic fields. Because these bacteria synthesize high quality crystals, research has focused on imitating aspects of this biomineralization in vitro. In particular, a biomineralization iron-binding protein found in a certain species of magnetotactic bacteria, magnetospirillum magneticum, AMB-1, has been extracted and used for in vitro magnetite synthesis; Pluronic F127 gel was used to increase the viscosity of the reaction medium to better mimic the conditions in the bacteria. It was shown that the biomineralization protein mms6 was able to facilitate uniform magnetite synthesis. In addition, a similar biomineralization process using mms6 and a shorter version of this protein, C25, has been used to synthesize cobalt ferrite

  7. Understanding Synthesis Across Disciplines to Improve Nursing Education.

    Science.gov (United States)

    Blondy, Laurie C; Blakeslee, Ann M; Scheffer, Barbara K; Rubenfeld, M Gaie; Cronin, Brenda M; Luster-Turner, Rose

    2016-06-01

    Nursing students must learn higher-order thinking skills of analysis and synthesis to manage complex data for decision making in healthcare. Teaching synthesis, however, is challenging and elusive due to lack of understanding of the concept and an explicit pedagogy for teaching it. A qualitative, multi-phased research project was designed to gain understanding of what synthesis is, how professionals acquire synthesis skills, and how to best teach synthesis. The first phase explored interdisciplinary descriptions of synthesis. Three focus groups were conducted, and interdisciplinary participants responded to several questions. Several themes emerged suggesting that synthesis depends on cognitive skills and competencies, situational and contextual factors, preparation and knowledge acquisition skills, interpersonal and interaction skills, and personal qualities. Participants also supported use of multi-modal teaching strategies to reinforce students' use of synthesis in learning. This project provided a beginning understanding of the synthesis process, revealing striking similarities in synthesis across professional disciplines. © The Author(s) 2015.

  8. "Best fit" framework synthesis: refining the method.

    Science.gov (United States)

    Carroll, Christopher; Booth, Andrew; Leaviss, Joanna; Rick, Jo

    2013-03-13

    Following publication of the first worked example of the "best fit" method of evidence synthesis for the systematic review of qualitative evidence in this journal, the originators of the method identified a need to specify more fully some aspects of this particular derivative of framework synthesis. We therefore present a second such worked example in which all techniques are defined and explained, and their appropriateness is assessed. Specified features of the method include the development of new techniques to identify theories in a systematic manner; the creation of an a priori framework for the synthesis; and the "testing" of the synthesis. An innovative combination of existing methods of quality assessment, analysis and synthesis is used to complete the process. This second worked example was a qualitative evidence synthesis of employees' views of workplace smoking cessation interventions, in which the "best fit" method was found to be practical and fit for purpose. The method is suited to producing context-specific conceptual models for describing or explaining the decision-making and health behaviours of patients and other groups. It offers a pragmatic means of conducting rapid qualitative evidence synthesis and generating programme theories relating to intervention effectiveness, which might be of relevance both to researchers and policy-makers.

  9. Novel Flame-Based Synthesis of Nanowires for Multifunctional Application

    Science.gov (United States)

    2015-05-13

    laser-based diagnostics for in-situ Raman characterization of as- synthesized nanomaterials, (iv) flame synthesis of graphene , (v) flame synthesis of...laser- based diagnostics for in-situ Raman characterization of as-synthesized nanomaterials, (iv) flame synthesis of graphene , (v) flame synthesis of...Stephen D. Tse, Manish Chhowalla, Bernard H. Kear. Role of substrate, temperature, and hydrogen on the flame synthesis of graphene films, Proceedings

  10. Synthesis of nano anatase for titanosilicate ETS-10 synthesis

    Science.gov (United States)

    Shafeque, Shihara

    Functionalized textiles present a vast and growing niche in the global textile market at US $400 billion [1, 2]. Engelhard Titanium Silicate 10 (ETS-10), a photocatalytic zeo-type material if coated on textiles, is expected to impart useful properties similar to TiO2, such as stain-resistant, odor repellant, bactericidal and enhanced UV protection [3, 4]. Typically, small ETS-10 crystals of size ˜300-800 nm are synthesized using solid titania (e.g., anatase or P25) sources [5, 6, 7]. However, smaller ETS-10 crystals are required for a uniform surface coating with highly effective surface area. The dissolution of titania particles (i.e., their size) is hypothesized to be important in small ETS-10 crystal formation [5, 6, 7]. Nano anatase was synthesized by modification of two methods: direct precipitation [7] and sol-gel synthesis [3]. Analysis by XRD confirmed that both methods produced nano anatase of crystallite size ˜4-5 nm. However, FE-SEM analysis showed that product from direct precipitation, existed as intergrown spheroidal particles with size ˜1.0 mum. These particles dispersed poorly in deionized water. Therefore, the best nano anatase samples were from sol-gel synthesis in two forms, dry powder and colloidal anatase. ETS-10 synthesis was investigated using two methods adopted from literature [6, 7]. The method of Yoon and co-workers [7], with nano anatase in a molar composition of 5.5TEOS: TiO2: 8.4NaOH: 1.43KF: 350H2O: 2.2H2SO4 produced unknown phase(s) with some ETS-10 and quartz. Using colloidal anatase with molar composition 5.5TEOS:1.0TiO 2:8.4NaOH:1.43KF:400H2O:2.2H2SO4 also produced unknown phase(s). The method of Anderson and co-workers [6] with nano anatase powder in a molar composition of 5.5SiO2: TiO 2: 5.2Na2O: 0.5K2O: 113H2O produced quartz with ETS-10 impurity. When colloidal anatase was used, with molar composition TiO2:5.5SiO2:5.2Na2O:0.5K2O:332H 2O, unreacted anatase and quartz were formed. It was hypothesized that the very low

  11. Synthesis of cyanopyridine based conjugated polymer

    Directory of Open Access Journals (Sweden)

    B. Hemavathi

    2016-06-01

    Full Text Available This data file contains the detailed synthetic procedure for the synthesis of two new cyanopyridine based conjugated polymer P1 and P2 along with the synthesis of its monomers. The synthesised polymers can be used for electroluminescence and photovoltaic (PV application. The physical data of the polymers are provided in this data file along with the morphological data of the polymer thin films. The data provided here are in association with the research article entitled ‘Cyanopyridine based conjugated polymer-synthesis and characterisation’ (Hemavathi et al., 2015 [3].

  12. Sonochemical Synthesis of Cobalt Ferrite Nanoparticles

    Directory of Open Access Journals (Sweden)

    Partha P. Goswami

    2013-01-01

    Full Text Available Cobalt ferrite being a hard magnetic material with high coercivity and moderate magnetization has found wide-spread applications. In this paper, we have reported the sonochemical synthesis of cobalt ferrite nanoparticles using metal acetate precursors. The ferrite synthesis occurs in three steps (hydrolysis of acetates, oxidation of hydroxides, and in situ microcalcination of metal oxides that are facilitated by physical and chemical effects of cavitation bubbles. The physical and magnetic properties of the ferrite nano-particles thus synthesized have been found to be comparable with those reported in the literature using other synthesis techniques.

  13. Recent advances on virtual human synthesis

    Institute of Scientific and Technical Information of China (English)

    XIA ShiHong; WANG ZhaoQi

    2009-01-01

    Virtual human is a digital representation of the geometric and behavioral property of human beings in the virtual environment generated by computer. The research goal of virtual human synthesis is to gen-erate realistic human body models and natural human motion behavior. This paper introduces the devel-opment of the related researches on these two topics, and some progresses on example based human modeling and motion synthesis, and their applications In Chinese sign language teaching, computer-aided sports training and public safety problem studying. Finally, some hot research topics in virtual human synthesis are presented.

  14. Improved Synthesis of Nefazodone from Phenol

    Institute of Scientific and Technical Information of China (English)

    LI Aijun; ZHOU Xueqin; LIU Dongzhi

    2006-01-01

    A route for the synthesis of nefazodone is reported. Nefazodone was obtained with an overall yield of 37.2% from phenol. The key steps involve the improved synthesis of 5-ethyl-4-(2-phenoxyethyl)-1, 2, 4-triazol-3(2H)-one, a key intermediate in the synthesis of nefazodone. The phenol was etherified with 1, 2-dichloroethane (75%), followed by iodination-amination with Nal and CH3OH-NH3(85.7%), acylation with ethyl chloroformate (95.7%) and cyclization with propionyl hydrazine (83.6%).

  15. Parameterized Synthesis Case Study: AMBA AHB

    Directory of Open Access Journals (Sweden)

    Roderick Bloem

    2014-07-01

    Full Text Available We revisit the AMBA AHB case study that has been used as a benchmark for several reactive synthesis tools. Synthesizing AMBA AHB implementations that can serve a large number of masters is still a difficult problem. We demonstrate how to use parameterized synthesis in token rings to obtain an implementation for a component that serves a single master, and can be arranged in a ring of arbitrarily many components. We describe new tricks - property decompositional synthesis, and direct encoding of simple GR(1 - that together with previously described optimizations allowed us to synthesize a component model with 14 states in about 1 hour.

  16. Green chemistry oriented organic synthesis in water.

    Science.gov (United States)

    Simon, Marc-Olivier; Li, Chao-Jun

    2012-02-21

    The use of water as solvent features many benefits such as improving reactivities and selectivities, simplifying the workup procedures, enabling the recycling of the catalyst and allowing mild reaction conditions and protecting-group free synthesis in addition to being benign itself. In addition, exploring organic chemistry in water can lead to uncommon reactivities and selectivities complementing the organic chemists' synthetic toolbox in organic solvents. Studying chemistry in water also allows insight to be gained into Nature's way of chemical synthesis. However, using water as solvent is not always green. This tutorial review briefly discusses organic synthesis in water with a Green Chemistry perspective.

  17. Coinage Metal Hydrides: Synthesis, Characterization, and Reactivity.

    Science.gov (United States)

    Jordan, Abraham J; Lalic, Gojko; Sadighi, Joseph P

    2016-08-10

    Hydride complexes of copper, silver, and gold encompass a broad array of structures, and their distinctive reactivity has enabled dramatic recent advances in synthesis and catalysis. This Review summarizes the synthesis, characterization, and key stoichiometric reactions of isolable or observable coinage metal hydrides. It discusses catalytic processes in which coinage metal hydrides are known or probable intermediates, and presents mechanistic studies of selected catalytic reactions. The purpose of this Review is to convey how developments in coinage metal hydride chemistry have led to new organic transformations, and how developments in catalysis have in turn inspired the synthesis of reactive new complexes.

  18. Synthesis

    DEFF Research Database (Denmark)

    2017-01-01

    is challenging, and focus on the different nature of the challenges for consumption poverty line estimation and multidimensional poverty measurement. The six case studies uniformly indicate that the process of drawing appropriate absolute poverty lines is not straightforward and cannot be done mechanically......, and are, almost by definition, vulnerable to shocks....

  19. Synthesis,

    Directory of Open Access Journals (Sweden)

    Ganesan Vanangamudi

    2017-02-01

    Full Text Available Twelve 2,5-dimethyl-3-thienyl chalcones [E-1-(2,5-dimethyl-3-thienyl-3-(substituted phenyl-2-propen-1-ones] have been synthesized by Claisen–Schmidt condensation of 3-acetyl-2,5-dimethyl furon and substituted benzaldehydes. Yields of the chalcones are more than 80%. These chalcones were characterized by their physical constants and spectral data. The group frequencies of infrared ν(cm−1 of CO s-cis and s-trans, CH in-plane and out of plane, CHCH out of plane, >CC< out of plane modes, NMR chemical shifts δ(ppm of Hα, Hβ, CO, Cα and Cβ of these chalcones were correlated with Hammett substituent constants, F and R parameters using single and multi-regression analyses. From the results of statistical analyses, the effects of substituents on the group frequencies are explained. Antibacterial, antifungal, antioxidant and insect antifeedant activities of these chalcones have been studied.

  20. Synthesis

    Directory of Open Access Journals (Sweden)

    Akshay Kumar

    2013-12-01

    Full Text Available Driven by the increased demand of pyrazolines exhibiting biological activities like antioxidant, anti-inflammatory, antidepressant, antimicrobial, antitumor, and antitubercular drug activity as a stable fragment in biological moieties, lead us to synthesize 2-pyrazolines by the condensation of various substituted chalcones and hydrazine hydrate in the presence of ethanol. The structure of the synthesized molecules was confirmed on the basis of physical data and extensive spectral studies. All the 13 compounds have been screened for antioxidant activity using DPPH radical scavenging method, NO scavenging assay, superoxide radical scavenging assay and hydrogen peroxide radical scavenging assay. All the compounds showed good free radical scavenging activity which is comparable to that of the standard ascorbic acid, out of which ATP-1, ATP-2 and ATP-3 come out to be the best molecules with an IC50 less than 40 mcg/ml. The results indicated that 2-pyrazolines could be the potential candidates eliciting antioxidant activity, and further studies can be conducted using molecular modeling tools for designing 2-pyrazolines having better activity.

  1. Synthesis of the Enantiomers of Tedanalactam and the First Total Synthesis and Configurational Assignment of (+)-Piplaroxide.

    Science.gov (United States)

    Romero-Ibañez, Julio; Xochicale-Santana, Leonardo; Quintero, Leticia; Fuentes, Lilia; Sartillo-Piscil, Fernando

    2016-04-22

    Highlighting the recently established methodology for the direct synthesis of glycidic amides from tertiary allyl amines, the synthesis of the enantiomers of tedanalactam were completed in two steps from the corresponding chiral dihydropiperidine. Additionally, the (+)- and (-)-enantiomers of piplaroxide were obtained from their respective tedanalactam precursor, and the absolute configuration of the naturally occurring (+)-piplaroxide was determined. The present approach represents not only the shortest synthesis of (-)-tedanalactam but also the first total synthesis of (+)-piplaroxide, a repellent against the leafcutter ant Atta cephalotes.

  2. Synthesis of Reliable Telecommunication Networks

    Directory of Open Access Journals (Sweden)

    Dusan Trstensky

    2005-01-01

    Full Text Available In many application, the network designer may to know to senthesise a reliable telecommunication network. Assume that a network, denoted Gm,e has the number of nodes n and the number of edges e, and the operational probability of each edge is known. The system reliability of the network is defined to be the reliability that every pair of nodes can communicate with each other. A network synthesis problem considered in this paper is to find a network G*n,e, that maximises system reliability over the class of all networks for the classes of networks Gn,n-1, Gn,m and Gn,n+1 respectively. In addition an upper bound of maximum reliability for the networks with n-node and e-edge (e>n+2 is derived in terms of node. Computational experiments for the reliability upper are also presented. the results show, that the proposed reliability upper bound is effective.

  3. GASP- GENERAL AVIATION SYNTHESIS PROGRAM

    Science.gov (United States)

    Galloway, T. L.

    1994-01-01

    The General Aviation Synthesis Program, GASP, was developed to perform tasks generally associated with the preliminary phase of aircraft design. GASP gives the analyst the capability of performing parametric studies in a rapid manner during preliminary design efforts. During the development of GASP, emphasis was placed on small fixed-wing aircraft employing propulsion systems varying from a single piston engine with a fixed pitch propeller through twin turboprop/turbofan systems as employed in business or transport type aircraft. The program is comprised of modules representing the various technical disciplines of design, integrated into a computational flow which ensures that the interacting effects of design variables are continuously accounted for in the aircraft sizing procedures. GASP provides a useful tool for comparing configurations, assessing aircraft performance and economics, and performing tradeoff and sensitivity studies. By utilizing GASP, the impact of various aircraft requirements and design factors may be studied in a systematic manner, with benefits being measured in terms of overall aircraft performance and economics. The GASP program consists of a control module and six "technology" submodules which perform the various independent studies required in the design of general aviation or small transport type aircraft. The six technology modules include geometry, aerodynamics, propulsion, weight and balance, mission analysis, and economics. The geometry module calculates the dimensions of the synthesized aircraft components based on such input parameters as number of passengers, aspect ratio, taper ratio, sweep angles, and thickness of wing and tail surfaces. The aerodynamics module calculates the various lift and drag coefficients of the synthesized aircraft based on inputs concerning configuration geometry, flight conditions, and type of high lift device. The propulsion module determines the engine size and performance for the synthesized aircraft

  4. Total synthesis of bryostatin 1.

    Science.gov (United States)

    Keck, Gary E; Poudel, Yam B; Cummins, Thomas J; Rudra, Arnab; Covel, Jonathan A

    2011-02-02

    Bryostatin 1 is a marine natural product that is a very promising lead compound because of the potent biological activity it displays against a variety of human disease states. We describe herein the first total synthesis of this agent. The synthetic route adopted is a highly convergent one in which the preformed, heavily functionalized pyran rings A and C are united by "pyran annulation", the TMSOTf-promoted reaction between a hydroxyallylsilane appended to the A-ring fragment and an aldehyde contained in the C-ring fragment, with concomitant formation of the B ring. Further elaborations of the resulting very highly functionalized intermediate include macrolactonization and selective cleavage of just one of five ester linkages present.

  5. Synthesis of B6 vitamin

    Directory of Open Access Journals (Sweden)

    Vučijak Nevena Ž.

    2009-01-01

    Full Text Available The importance of vitamin B6 has been known since its discovery in the 1940's. Chemical tests, elestrometric titration determinations, and absorption spectrum studies showed that this vitamin exists in three major chemical forms: pyridoxine (an alcohol, pyridoxal (an aldehyde, and pyridoxamine (a primary amine. Vitamin B6 is needed for more than 100 enzymes involved in protein metabolism, and it is assumed that this vitamin is cofactor of metabolic processes more important than any other substance. A deficiency of vitamin B6 in the human diet leads to severe disorders. Vitamin B6 is necessary for the proper function of the immune and nervous system, and helps the body convert protein to energy. This paper describes the history, properties and applications of vitamin B6, elucidation of chemical structure, and different procedures for synthesis of pyridoxine and pyridoxamine.

  6. Triboluminescence theory, synthesis, and application

    CERN Document Server

    Okoli, Okenwa; Fontenot, Ross; Hollerman, William

    2016-01-01

    This book expounds on progress made over the last 35 years in the theory, synthesis, and application of triboluminescence for creating smart structures. It presents in detail the research into utilization of the triboluminescent properties of certain crystals as new sensor systems for smart engineering structures, as well as triboluminescence-based sensor systems that have the potential to enable wireless, in-situ, real time and distributed (WIRD) structural health monitoring of composite structures. The sensor component of any structural health monitoring (SHM) technology — measures the effects of the external load/event and provides the necessary inputs for appropriate preventive/corrective action to be taken in a smart structure — sits at the heart of such a system. This volume explores advances in materials properties and structural behavior underlying creation of smart composite structures and sensor systems for structural health monitoring of critical engineering structures, such as bridges, aircraf...

  7. Mechanochemical synthesis of cerium orthophosphate

    Institute of Scientific and Technical Information of China (English)

    A.Matraszek; I.Szczygiei; L.Macalik; J.Hanuza

    2009-01-01

    A facile,simple and rapid preparation method of cerium orthophosphate was presented.The synthesis of low-crystalline CePO4 occurred upon mixing of cerium (Ⅲ) nitrate and sodium phosphate,and was an exchange-type reaction.The phase composition of the obtained powder was checked by the XRD and FTIR methods,indicating the presence of cerium phosphate.Further investigations on thermal behavior of the synthesized cerium salt had shown that the obtained onhophosphate crystallized at first in rhabdophane-type structure.It convetted to monazite (monoclinic symmetry) during heating at the temperatures of above 600 ℃.Oxidation of Ce3+ to Ce4+ was avoided during the syntheses,as confirmed by the XPS experiments.

  8. Synthesis of nanoparticles using ethanol

    Science.gov (United States)

    Wang, Jia Xu

    2017-01-24

    The present disclosure relates to methods for producing nanoparticles. The nanoparticles may be made using ethanol as the solvent and the reductant to fabricate noble-metal nanoparticles with a narrow particle size distributions, and to coat a thin metal shell on other metal cores. With or without carbon supports, particle size is controlled by fine-tuning the reduction power of ethanol, by adjusting the temperature, and by adding an alkaline solution during syntheses. The thickness of the added or coated metal shell can be varied easily from sub-monolayer to multiple layers in a seed-mediated growth process. The entire synthesis of designed core-shell catalysts can be completed using metal salts as the precursors with more than 98% yield; and, substantially no cleaning processes are necessary apart from simple rinsing. Accordingly, this method is considered to be a "green" chemistry method.

  9. Zeolite synthesis: an energetic perspective.

    Science.gov (United States)

    Zwijnenburg, Martijn A; Bromley, Stefan T

    2010-11-21

    Taking |D(H(2)O)(x)|[AlSiO(4)] based materials (where D is Li, Na, K, Rb or Cs) as an archetypal aluminosilicate system, we use accurate density functional theory calculations to demonstrate how the substitution of silicon cations in silica, with pairs of aluminium and (alkali metal) cations, changes the energetic ordering of different competing structure-types. For large alkali metal cations we further show that the formation of porous aluminosilicate structures, the so-called zeolites, is energetically favored. These findings unequivocally demonstrate that zeolites can be energetic preferred reaction products, rather than being kinetically determined, and that the size of the (hydrated) cations in the pore, be it inorganic or organic, is critical for directing zeolite synthesis.

  10. Silica Aerogel: Synthesis and Applications

    Directory of Open Access Journals (Sweden)

    Jyoti L. Gurav

    2010-01-01

    Full Text Available Silica aerogels have drawn a lot of interest both in science and technology because of their low bulk density (up to 95% of their volume is air, hydrophobicity, low thermal conductivity, high surface area, and optical transparency. Aerogels are synthesized from molecular precursors by sol-gel processing. Special drying techniques must be applied to replace the pore liquid with air while maintaining the solid network. Supercritical drying is most common; however, recently developed methods allow removal of the liquid at atmospheric pressure after chemical modification of the inner surface of the gels, leaving only a porous silica network filled with air. Therefore, by considering the surprising properties of aerogels, the present review addresses synthesis of silica aerogels by the sol-gel method, as well as drying techniques and applications in current industrial development and scientific research.

  11. Synthesis of nanoparticles using ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jia Xu

    2017-01-24

    The present disclosure relates to methods for producing nanoparticles. The nanoparticles may be made using ethanol as the solvent and the reductant to fabricate noble-metal nanoparticles with a narrow particle size distributions, and to coat a thin metal shell on other metal cores. With or without carbon supports, particle size is controlled by fine-tuning the reduction power of ethanol, by adjusting the temperature, and by adding an alkaline solution during syntheses. The thickness of the added or coated metal shell can be varied easily from sub-monolayer to multiple layers in a seed-mediated growth process. The entire synthesis of designed core-shell catalysts can be completed using metal salts as the precursors with more than 98% yield; and, substantially no cleaning processes are necessary apart from simple rinsing. Accordingly, this method is considered to be a "green" chemistry method.

  12. A Prebiotic Synthesis of Pterins.

    Science.gov (United States)

    Marín-Yaseli, Margarita R; Mompeán, Cristina; Ruiz-Bermejo, Marta

    2015-09-21

    The genesis of life on Earth is a hypothesis of evolutionary science that can be, at least partially, tested experimentally. The prebiotic synthesis of cofactors or coenzymes is a poorly explored issue, likely because their formation under plausible prebiotic conditions is not clear. In this sense, it has been proposed that the cofactors are "molecular fossils" of an early phase of life. In contrast, Eschenmoser and Loewenthal suggested a prebiotic hydrocyanic origin of cofactor building blocks. In the present paper, the formation of a set of pterins from cyanide polymerizations is demonstrated, showing that the main structure of some cofactors can be prebiotically formed. Indeed, it was observed that aqueous aerosols additionally increase the relative composition for pterins in the insoluble NH4CN polymers synthesized. The novel identification of pterins in NH4CN polymers, together with the previous detection of other important biomonomers, indicates that cyanide polymerizations were essential in the early state of prebiotic chemistry.

  13. Synthesis and characterization of Taurine

    Directory of Open Access Journals (Sweden)

    B Bayarmaa

    2014-10-01

    Full Text Available Have been obtained 2-aminoethanesulfonic acid (taurine from ethanolamine, sulfuric acid and sodium sulfite during the synthesis in laboratory condition. The process involves two steps of reactions, the first was esterification of ethanolamine with sulfuric acid to produce the intermediate product of 2-aminoethyl ester which than was extended to the second step by sulfonation with sodium sulfite to produce 2-aminoethanesulfonic acid. Resulting product was analyzed using 1H-NMR, IR, FAB-MS analysis and examined purity characterizations of the synthesized products. DOI: http://dx.doi.org/10.5564/mjc.v14i0.200 Mongolian Journal of Chemistry 14 (40, 2013, p57-60

  14. Energy management and vehicle synthesis

    Science.gov (United States)

    Czysz, P.; Murthy, S. N. B.

    1995-01-01

    The major drivers in the development of launch vehicles for the twenty-first century are reduction in cost of vehicles and operations, continuous reusability, mission abort capability with vehicle recovery, and readiness. One approach to the design of such vehicles is to emphasize energy management and propulsion as being the principal means of improvements given the available industrial capability and the required freedom in selecting configuration concept geometries. A methodology has been developed for the rational synthesis of vehicles based on the setting up and utilization of available data and projections, and a reference vehicle. The application of the methodology is illustrated for a single stage to orbit (SSTO) with various limits for the use of airbreathing propulsion.

  15. Algorithmic synthesis using Python compiler

    Science.gov (United States)

    Cieszewski, Radoslaw; Romaniuk, Ryszard; Pozniak, Krzysztof; Linczuk, Maciej

    2015-09-01

    This paper presents a python to VHDL compiler. The compiler interprets an algorithmic description of a desired behavior written in Python and translate it to VHDL. FPGA combines many benefits of both software and ASIC implementations. Like software, the programmed circuit is flexible, and can be reconfigured over the lifetime of the system. FPGAs have the potential to achieve far greater performance than software as a result of bypassing the fetch-decode-execute operations of traditional processors, and possibly exploiting a greater level of parallelism. This can be achieved by using many computational resources at the same time. Creating parallel programs implemented in FPGAs in pure HDL is difficult and time consuming. Using higher level of abstraction and High-Level Synthesis compiler implementation time can be reduced. The compiler has been implemented using the Python language. This article describes design, implementation and results of created tools.

  16. Control synthesis of switched systems

    CERN Document Server

    Zhao, Xudong; Niu, Ben; Wu, Tingting

    2017-01-01

    This book offers its readers a detailed overview of the synthesis of switched systems, with a focus on switching stabilization and intelligent control. The problems investigated are not only previously unsolved theoretically but also of practical importance in many applications: voltage conversion, naval piloting and navigation and robotics, for example. The book considers general switched-system models and provides more efficient design methods to bring together theory and application more closely than was possible using classical methods. It also discusses several different classes of switched systems. For general switched linear systems and switched nonlinear systems comprising unstable subsystems, it introduces novel ideas such as invariant subspace theory and the time-scheduled Lyapunov function method of designing switching signals to stabilize the underlying systems. For some typical switched nonlinear systems affected by various complex dynamics, the book proposes novel design approaches based on inte...

  17. Diversity-Oriented Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    J. Wu

    2005-01-01

    @@ 1Introduction A goal of chemical genetics is to find small molecules that modulate the individual functions of gene products with high potency and high specificity[1,2]. Natural products and natural product-derived compounds provide many of the most striking examples, particularly in terms of their specificity. It seems unlikely that natural products alone will provide the hypothetical "complete" set of small molecules that would allow the functions of all proteins, as well as their individual domains, to be determined. For chemistry to have its maximal effect on biology, efficient methods based on diversity-oriented organic synthesis for discovering this set of small molecules are in great demand(See Fig. 1).

  18. Synthesis gas method and apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Sean M.; Kromer, Brian R.; Litwin, Michael M.; Rosen, Lee J.; Christie, Gervase Maxwell; Wilson, Jamie; Kosowski, Lawrence W; Robinson, Charles

    2015-11-06

    A method and apparatus for producing a synthesis gas product having one or more oxygen transport membrane elements thermally coupled to one or more catalytic reactors such that heat generated from the oxygen transport membrane element supplies endothermic heating requirements for steam methane reforming reactions occurring within the catalytic reactor through radiation and convention heat transfer. A hydrogen containing stream containing no more than 20 percent methane is combusted within the oxygen transport membrane element to produce the heat and a heated combustion product stream. The heated combustion product stream is combined with a reactant stream to form a combined stream that is subjected to the reforming within the catalytic reactor. The apparatus may include modules in which tubular membrane elements surround a central reactor tube.

  19. Combustion synthesis of bulk nanocrystalline iron alloys

    Directory of Open Access Journals (Sweden)

    Licai Fu

    2016-02-01

    Full Text Available The controlled synthesis of large-scale nanocrystalline metals and alloys with predefined architecture is in general a big challenge, and making full use of these materials in applications still requires greatly effort. The combustion synthesis technique has been successfully extended to prepare large-scale nanocrystalline metals and alloys, especially iron alloy, such as FeC, FeNi, FeCu, FeSi, FeB, FeAl, FeSiAl, FeSiB, and the microstructure can be designed. In this issue, recent progress on the synthesis of nanocrystalline metals and alloys prepared by combustion synthesis technique are reviewed. Then, the mechanical and tribological properties of these materials with microstructure control are discussed.

  20. Copper catalysed synthesis of indolylquinazolinone alkaloid bouchardatine

    Indian Academy of Sciences (India)

    Mayavan Viji; Rajagopal Nagarajan

    2014-07-01

    We describe the total synthesis of indolylquinazolinone alkaloid bouchardatine and some of the quinazolinone derivatives. The aerobic oxidation induced by copper(I) bromide, followed by Vilsmeier-Haack formylation gives the natural product bouchardatine alkaloid in good yield.

  1. Synthesis of exemestane labelled with (13)C.

    Science.gov (United States)

    Fontana, Erminia; Pignatti, Alberto; Giribone, Danilo; Di Salle, Enrico

    2008-08-01

    The synthesis of exemestane Aromasin, an irreversible steroidal aromatase inhibitor, specifically labelled with (13)C is reported. The preparation of [(13)C(3)]exemestane was achieved according to an eight-step procedure starting from the commercially available testosterone.

  2. Solvent-Free Synthesis of New Coumarins

    Directory of Open Access Journals (Sweden)

    Redah I. Al-Bayati

    2012-01-01

    Full Text Available A solvent-free synthesis of five series of coumarin derivatives using microwave assistant is presented herein. The synthesized compounds are fully characterized by UV-VIS, FT-IR, and NMR spectroscopy.

  3. Enzymic synthesis of labelled chiral substances.

    Science.gov (United States)

    Battersby, A R

    1985-01-01

    The enzymic synthesis of chiral substances in which one hydrogen atom of a methylene group has been replaced by deuterium or tritium is illustrated. Such labelled products can be used to determine the stereochemistry of other enzyme-catalysed reactions.

  4. Regional Synthesis for State Wildlife Action Plans

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The North Atlantic LCC and Northeast states are developing a synthesis of regional conservation information for State Wildlife Action Plan (SWAP) revisions. Compiled...

  5. Iridium catalysed synthesis of piperazines from diols

    DEFF Research Database (Denmark)

    Nordstrøm, Lars Ulrik Rubæk; Madsen, Robert

    2007-01-01

    A green and atom-economical method has been developed for the synthesis of piperazines by cyclocondensation of diols and amines in aqueous media in the presence of a catalytic amount of [Cp*IrCl2]2....

  6. Solving fault diagnosis problems linear synthesis techniques

    CERN Document Server

    Varga, Andreas

    2017-01-01

    This book addresses fault detection and isolation topics from a computational perspective. Unlike most existing literature, it bridges the gap between the existing well-developed theoretical results and the realm of reliable computational synthesis procedures. The model-based approach to fault detection and diagnosis has been the subject of ongoing research for the past few decades. While the theoretical aspects of fault diagnosis on the basis of linear models are well understood, most of the computational methods proposed for the synthesis of fault detection and isolation filters are not satisfactory from a numerical standpoint. Several features make this book unique in the fault detection literature: Solution of standard synthesis problems in the most general setting, for both continuous- and discrete-time systems, regardless of whether they are proper or not; consequently, the proposed synthesis procedures can solve a specific problem whenever a solution exists Emphasis on the best numerical algorithms to ...

  7. Synthesis of substituted 2-cyanoarylboronic esters

    DEFF Research Database (Denmark)

    Lysén, Morten; Hansen, Henriette M; Begtrup, Mikael

    2006-01-01

    The synthesis of substituted 2-cyanoarylboronic esters is described via lithiation/in situ trapping of the corresponding methoxy-, trifluoromethyl-, fluoro-, chloro-, and bromobenzonitriles. The crude arylboronic esters were obtained in high yields and purities and with good regioselectivities....

  8. Catalytic Asymmetric Synthesis of Phosphine Boronates

    NARCIS (Netherlands)

    Hornillos, Valentin; Vila, Carlos; Otten, Edwin; Feringa, Ben L.

    2015-01-01

    The first catalytic enantioselective synthesis of ambiphilic phosphine boronate esters is presented. The asymmetric boration of ,-unsaturated phosphine oxides catalyzed by a copper bisphosphine complex affords optically active organoboronate esters that bear a vicinal phosphine oxide group in good y

  9. Combustion synthesis of bulk nanocrystalline iron alloys

    Institute of Scientific and Technical Information of China (English)

    Licai Fu; Jun Yang; Weimin Liu

    2016-01-01

    The controlled synthesis of large-scale nanocrystalline metals and alloys with predefined architecture is in general a big challenge, and making full use of these materials in applications still requires greatly effort. The combustion synthesis technique has been successfully extended to prepare large-scale nanocrystalline metals and alloys, especially iron alloy, such as FeC, FeNi, FeCu, FeSi, FeB, FeAl, FeSiAl, FeSiB, and the microstructure can be designed. In this issue, recent progress on the synthesis of nanocrystalline metals and alloys prepared by combustion synthesis technique are reviewed. Then, the mechanical and tribological properties of these materials with microstructure control are discussed.

  10. Anthrax carbohydrates, synthesis and uses thereof

    Science.gov (United States)

    Carlson, Russell W.; Boons, Geert-Jan; Quinn, Conrad; Vasan, Mahalakshmi; Wolfert, Margreet A.; Choudhury, Biswa; Kannenberg, Elmar; Leoff, Christine; Mehta, Alok; Saile, Elke; Rauvolfova, Jana; Wilkins, Patricia; Harvey, Alex J.

    2013-04-16

    The present invention presents the isolation, characterization and synthesis of oligosaccharides of Bacillus anthracis. Also presented are antibodies that bind to such saccharide moieties and various methods of use for such saccharide moieties and antibodies.

  11. Novel Green Synthesis and Characterization of Nanopolymer ...

    African Journals Online (AJOL)

    1King Abdullah Institute for Nanotechnology, 2Department of Chemical Engineering, ... Methods: Green synthesis of nano-polymer porous gold oxide nanoparticles ... UV (ultraviolet (UV) visible spectroscopy and dynamic light scattering (DLS) ...

  12. A Convergent Total Synthesis of Methoxatin

    NARCIS (Netherlands)

    Hendrickson, James B.; Vries, Johannes G. de

    1982-01-01

    We report a convergent total synthesis of the coenzyme methoxatin (1) by linking a pyrrole subunit with an uvitonic acid derivative and oxidative photocyclization to a deoxymethoxatin triester, followed by seven refunctionalization steps to 1.

  13. Plant cellulose synthesis: CESA proteins crossing kingdoms.

    Science.gov (United States)

    Kumar, Manoj; Turner, Simon

    2015-04-01

    Cellulose is a biopolymer of considerable economic importance. It is synthesised by the cellulose synthase complex (CSC) in species ranging from bacteria to higher plants. Enormous progress in our understanding of bacterial cellulose synthesis has come with the recent publication of both the crystal structure and biochemical characterisation of a purified complex able to synthesis cellulose in vitro. A model structure of a plant CESA protein suggests considerable similarity between the bacterial and plant cellulose synthesis. In this review article we will cover current knowledge of how plant CESA proteins synthesise cellulose. In particular the focus will be on the lessons learned from the recent work on the catalytic mechanism and the implications that new data on cellulose structure has for the assembly of CESA proteins into the large complex that synthesis plant cellulose microfibrils.

  14. Synthesis of novel spiro--lactams

    Indian Academy of Sciences (India)

    Renu Arora; P Venugopalan; S S Bari

    2010-03-01

    A new synthetic approach for spiro--lactams by cyclization of cis-3-allyl-3-benzylthio--lactams is presented. The reaction involves step-wise electrophilic addition-dealkylation sequence giving stereospecific synthesis of C-3-spiro--lactams.

  15. Structured synthesis of MEMS using evolutionary approaches

    DEFF Research Database (Denmark)

    Fan, Zhun; Wang, Jiachuan; Achiche, Sofiane

    2008-01-01

    In this paper, we discuss the hierarchy that is involved in a typical MEMS design and how evolutionary approaches can be used to automate the hierarchical synthesis process for MEMS. The paper first introduces the flow of a structured MEMS design process and emphasizes that system-level lumped......-parameter model synthesis is the first step of the MEMS synthesis process. At the system level, an approach combining bond graphs and genetic programming can lead to satisfactory design candidates as system-level models that meet the predefined behavioral specifications for designers to trade off....... Then at the physical layout synthesis level, the selection of geometric parameters for component devices and other design variables is formulated as a constrained optimization problem and addressed using a constrained genetic algorithm approach. A multiple-resonator microsystem design is used to illustrate...

  16. Chronological protein synthesis in regenerating rat liver.

    Science.gov (United States)

    He, Jinjun; Hao, Shuai; Zhang, Hao; Guo, Fuzheng; Huang, Lingyun; Xiao, Xueyuan; He, Dacheng

    2015-07-01

    Liver regeneration has been studied for decades; however, its regulation remains unclear. In this study, we report a dynamic tracing of protein synthesis in rat regenerating liver with a new proteomic technique, (35) S in vivo labeling analysis for dynamic proteomics (SiLAD). Conventional proteomic techniques typically measure protein alteration in accumulated amounts. The SiLAD technique specifically detects protein synthesis velocity instead of accumulated amounts of protein through (35) S pulse labeling of newly synthesized proteins, providing a direct way for analyzing protein synthesis variations. Consequently, protein synthesis within short as 30 min was visualized and protein regulations in the first 8 h of regenerating liver were dynamically traced. Further, the 3.5-5 h post partial hepatectomy (PHx) was shown to be an important regulatory turning point by acute regulation of many proteins in the initiation of liver regeneration.

  17. Protein Synthesis--An Interactive Game.

    Science.gov (United States)

    Clements, Lee Ann J.; Jackson, Karen E.

    1998-01-01

    Describes an interactive game designed to help students see and understand the dynamic relationship between DNA, RNA, and proteins. Appropriate for either a class or laboratory setting, following a lecture session about protein synthesis. (DDR)

  18. The First Total Synthesis of Isoliquiritin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A first total synthesis of isoliquiritin was accomplished starting from p-hydroxy- benzaldehyde and 2,4-dihydroxyacetylphenone. The key step is condensation reaction. In synthetic process need not protect the hydroxy group of reacting substance.

  19. Behavioral program synthesis with genetic programming

    CERN Document Server

    Krawiec, Krzysztof

    2016-01-01

    Genetic programming (GP) is a popular heuristic methodology of program synthesis with origins in evolutionary computation. In this generate-and-test approach, candidate programs are iteratively produced and evaluated. The latter involves running programs on tests, where they exhibit complex behaviors reflected in changes of variables, registers, or memory. That behavior not only ultimately determines program output, but may also reveal its `hidden qualities' and important characteristics of the considered synthesis problem. However, the conventional GP is oblivious to most of that information and usually cares only about the number of tests passed by a program. This `evaluation bottleneck' leaves search algorithm underinformed about the actual and potential qualities of candidate programs. This book proposes behavioral program synthesis, a conceptual framework that opens GP to detailed information on program behavior in order to make program synthesis more efficient. Several existing and novel mechanisms subs...

  20. Green Synthesis of Nanocrystals and Nanocomposites

    Science.gov (United States)

    Metal nanomaterials have attracted considerable attention because of their unique magnetic, optical, electrical, and catalytic properties and their potential applications in nanoelectronics as well as in various wet chemical synthesis methods. There is also great interest in synt...