WorldWideScience

Sample records for dictyostelium discoideum progress

  1. Retrotransposon Domestication and Control in Dictyostelium discoideum

    Directory of Open Access Journals (Sweden)

    Marek Malicki

    2017-10-01

    Full Text Available Transposable elements, identified in all eukaryotes, are mobile genetic units that can change their genomic position. Transposons usually employ an excision and reintegration mechanism, by which they change position, but not copy number. In contrast, retrotransposons amplify via RNA intermediates, increasing their genomic copy number. Hence, they represent a particular threat to the structural and informational integrity of the invaded genome. The social amoeba Dictyostelium discoideum, model organism of the evolutionary Amoebozoa supergroup, features a haploid, gene-dense genome that offers limited space for damage-free transposition. Several of its contemporary retrotransposons display intrinsic integration preferences, for example by inserting next to transfer RNA genes or other retroelements. Likely, any retrotransposons that invaded the genome of the amoeba in a non-directed manner were lost during evolution, as this would result in decreased fitness of the organism. Thus, the positional preference of the Dictyostelium retroelements might represent a domestication of the selfish elements. Likewise, the reduced danger of such domesticated transposable elements led to their accumulation, and they represent about 10% of the current genome of D. discoideum. To prevent the uncontrolled spreading of retrotransposons, the amoeba employs control mechanisms including RNA interference and heterochromatization. Here, we review TRE5-A, DIRS-1 and Skipper-1, as representatives of the three retrotransposon classes in D. discoideum, which make up 5.7% of the Dictyostelium genome. We compile open questions with respect to their mobility and cellular regulation, and suggest strategies, how these questions might be addressed experimentally.

  2. Characterization of a 1,4-{beta}-D-glucan synthase from Dictyostelium discoideum. Progress report, May 1990--January 1992

    Energy Technology Data Exchange (ETDEWEB)

    Blanton, R.L.

    1992-01-15

    Various aspects of research concerning Dictyostelium discoideum are presented. The initial focus of this project was upon: the characterization of potential probes for the cellulose synthase (antibody and nucleic acid), the determination of the cultural induction conditions of cellulose synthesis, the solubilization of the enzyme activity, the development of a non-inhibitory disruption buffer, the generation and isolation of mutant strains deficient in cellulose synthesis, and the development of the capability to determine the degree of polymerization of the in vitro product. I have briefly summarized our most significant findings with only selected data sets being shown in this report in the interest of brevity.

  3. Analysis of Rheb in the cellular slime mold Dictyostelium discoideum

    Indian Academy of Sciences (India)

    2014-01-27

    Jan 27, 2014 ... lyse the caspase-independent cell death mechanism. It is a ..... we observed exclusive expression in the prespore region. (figure 5A). There were ..... disc formation in Dictyostelium discoideum is an early event in culmination.

  4. Arachidonic acid is a chemoattractant for Dictyostelium discoideum

    Indian Academy of Sciences (India)

    Arachidonic acid is a chemoattractant for Dictyostelium discoideum cells ... Arachidonic acid; chemotaxis; fatty acids; iplA ... Previously, we have shown that arachidonic acid (AA) induces an increase in the cytosolic Ca2+ concentration by causing the release of Ca2+ from intracellular stores and activating influx of ...

  5. Diffusion-Assisted Aggregation and Synchronization in Dictyostelium discoideum

    Science.gov (United States)

    Nagano, Seido

    1998-05-01

    In biological pattern formation, chemotaxis and cell adhesion are essential. However, we lack quantitative data and a theory to understand their coordination. The cellular dynamics theory presented can clarify how Dictyostelium discoideum amoebae use diffusible cyclic adenosine 3',5'-monophosphate, and coordinate chemotaxis and cell adhesion during aggregation.

  6. The genome of the social amoeba Dictyostelium discoideum

    DEFF Research Database (Denmark)

    Eichinger, L; Pachebat, J A; Glöckner, G

    2005-01-01

    The social amoebae are exceptional in their ability to alternate between unicellular and multicellular forms. Here we describe the genome of the best-studied member of this group, Dictyostelium discoideum. The gene-dense chromosomes of this organism encode approximately 12,500 predicted proteins,...

  7. Calcium regulates the expression of a Dictyostelium discoideum ...

    Indian Academy of Sciences (India)

    In a screen for calcium-regulated gene expression during growth and development of Dictyostelium discoideum we have identified an asparaginyl tRNA synthetase (ddAsnRS) gene, the second tRNA synthetase gene identified in this organism. The ddAsnRS gene shows many unique features. One, it is repressed by ...

  8. A secreted protein is an endogenous chemorepellant in Dictyostelium discoideum

    OpenAIRE

    Phillips, Jonathan E.; Gomer, Richard H.

    2012-01-01

    Chemorepellants may play multiple roles in physiological and pathological processes. However, few endogenous chemorepellants have been identified, and how they function is unclear. We found that the autocrine signal AprA, which is produced by growing Dictyostelium discoideum cells and inhibits their proliferation, also functions as a chemorepellant. Wild-type cells at the edge of a colony show directed movement outward from the colony, whereas cells lacking AprA do not. Cells show directed mo...

  9. Chemotaxis of Dictyostelium discoideum: collective oscillation of cellular contacts.

    Directory of Open Access Journals (Sweden)

    Edith Schäfer

    Full Text Available Chemotactic responses of Dictyostelium discoideum cells to periodic self-generated signals of extracellular cAMP comprise a large number of intricate morphological changes on different length scales. Here, we scrutinized chemotaxis of single Dictyostelium discoideum cells under conditions of starvation using a variety of optical, electrical and acoustic methods. Amebas were seeded on gold electrodes displaying impedance oscillations that were simultaneously analyzed by optical video microscopy to relate synchronous changes in cell density, morphology, and distance from the surface to the transient impedance signal. We found that starved amebas periodically reduce their overall distance from the surface producing a larger impedance and higher total fluorescence intensity in total internal reflection fluorescence microscopy. Therefore, we propose that the dominant sources of the observed impedance oscillations observed on electric cell-substrate impedance sensing electrodes are periodic changes of the overall cell-substrate distance of a cell. These synchronous changes of the cell-electrode distance were also observed in the oscillating signal of acoustic resonators covered with amebas. We also found that periodic cell-cell aggregation into transient clusters correlates with changes in the cell-substrate distance and might also contribute to the impedance signal. It turned out that cell-cell contacts as well as cell-substrate contacts form synchronously during chemotaxis of Dictyostelium discoideum cells.

  10. Chemotaxis of Dictyostelium discoideum: Collective Oscillation of Cellular Contacts

    Science.gov (United States)

    Schäfer, Edith; Tarantola, Marco; Polo, Elena; Westendorf, Christian; Oikawa, Noriko; Bodenschatz, Eberhard; Geil, Burkhard; Janshoff, Andreas

    2013-01-01

    Chemotactic responses of Dictyostelium discoideum cells to periodic self-generated signals of extracellular cAMP comprise a large number of intricate morphological changes on different length scales. Here, we scrutinized chemotaxis of single Dictyostelium discoideum cells under conditions of starvation using a variety of optical, electrical and acoustic methods. Amebas were seeded on gold electrodes displaying impedance oscillations that were simultaneously analyzed by optical video microscopy to relate synchronous changes in cell density, morphology, and distance from the surface to the transient impedance signal. We found that starved amebas periodically reduce their overall distance from the surface producing a larger impedance and higher total fluorescence intensity in total internal reflection fluorescence microscopy. Therefore, we propose that the dominant sources of the observed impedance oscillations observed on electric cell-substrate impedance sensing electrodes are periodic changes of the overall cell-substrate distance of a cell. These synchronous changes of the cell-electrode distance were also observed in the oscillating signal of acoustic resonators covered with amebas. We also found that periodic cell-cell aggregation into transient clusters correlates with changes in the cell-substrate distance and might also contribute to the impedance signal. It turned out that cell-cell contacts as well as cell-substrate contacts form synchronously during chemotaxis of Dictyostelium discoideum cells. PMID:23349816

  11. Excitable signal relay in Dictyostelium discoideum

    Science.gov (United States)

    Mestler, Troy; Schwab, David; Mehta, Pankaj; Gregor, Thomas

    2011-03-01

    The social amoeba D. discoideum transitions when starved from a collection of individual cells into a multicellular spore-complex. During this process, amoebae display several interesting phenomena including intercellular signaling, pattern formation, and cell differentiation. At the heart of these phenomena is the exchange of the signaling molecule cyclic-AMP, which has previously been extensively studied using a variety of indirect methods. Here we employ a sensor that uses a compound fluorescent protein whose emission spectrum changes in the presence of bound cyclic AMP to directly monitor, in real time and in vivo, intracellular cAMP concentrations. We use cells expressing this sensor in microchemostats to study intracellular cAMP concentrations at the single-cell level in response to precise, dynamically-controlled external cAMP stimulation. Specifically, we show that these cells display excitability much like that found in neurons and agree experimentally quite well with a modified FitzHugh-Nagumo dynamical systems model. This single-cell model sets groundwork for a comprehensive multicellular model that promises to explain emergent behavior in D. discoideum.

  12. The Dictyostelium discoideum cellulose synthase: Structure/function analysis and identification of interacting proteins

    Energy Technology Data Exchange (ETDEWEB)

    Richard L. Blanton

    2004-02-19

    OAK-B135 The major accomplishments of this project were: (1) the initial characterization of dcsA, the gene for the putative catalytic subunit of cellulose synthase in the cellular slime mold Dictyostelium discoideum; (2) the detection of a developmentally regulated event (unidentified, but perhaps a protein modification or association with a protein partner) that is required for cellulose synthase activity (i.e., the dcsA product is necessary, but not sufficient for cellulose synthesis); (3) the continued exploration of the developmental context of cellulose synthesis and DcsA; (4) the isolation of a GFP-DcsA-expressing strain (work in progress); and (5) the identification of Dictyostelium homologues for plant genes whose products play roles in cellulose biosynthesis. Although our progress was slow and many of our results negative, we did develop a number of promising avenues of investigation that can serve as the foundation for future projects.

  13. Evidence for a Messenger Function of Cyclic GMP During Phosphodiesterase Induction in Dictyostelium discoideum

    NARCIS (Netherlands)

    Haastert, Peter J.M. van; Pasveer, Frank J.; Meer, Rob C. van der; Heijden, Paul R. van der; Walsum, Hans van; Konijn, Theo M.

    1982-01-01

    Chemotactic stimulation of vegetative or aggregative Dictyostelium discoideum cells induced a transient elevation of cyclic GMP levels. The addition of chemoattractants to postvegetative cells by pulsing induced phosphodiesterase activity. The following lines of evidence suggest a messenger function

  14. Identification and characterization of peptide: N- glycanase from Dictyostelium discoideum

    Directory of Open Access Journals (Sweden)

    Gosain Anuradha

    2012-06-01

    Full Text Available Abstract Background Peptide: N- glycanase (PNGase enzyme cleaves oligosaccharides from the misfolded glycoproteins and prepares them for degradation. This enzyme plays a role in the endoplasmic reticulum associated degradation (ERAD pathway in yeast and mice but its biological importance and role in multicellular development remain largely unknown. Results In this study, the PNGase from the cellular slime mold, Dictyostelium discoideum (DdPNGase was identified based on the presence of a common TG (transglutaminase core domain and its sequence homology with the known PNGases. The domain architecture and the sequence comparison validated the presence of probable functional domains in DdPNGase. The tertiary structure matched with the mouse PNGase. Here we show that DdPNGase is an essential protein, required for aggregation during multicellular development and a knockout strain of it results in small sized aggregates, all of which did not form fruiting bodies. The in situ hybridization and RT-PCR results show higher level of expression during the aggregate stage. The expression gets restricted to the prestalk region during later developmental stages. DdPNGase is a functional peptide:N-glycanase enzyme possessing deglycosylation activity, but does not possess any significant transamidation activity. Conclusions We have identified and characterized a novel PNGase from D. discoideum and confirmed its deglycosylation activity. The results emphasize the importance of PNGase in aggregation during multicellular development of this organism.

  15. Crystallization and preliminary characterization of dihydropteridine reductase from Dictyostelium discoideum

    International Nuclear Information System (INIS)

    Chen, Cong; Seo, Kyung Hye; Kim, Hye Lim; Zhuang, Ningning; Park, Young Shik; Lee, Kon Ho

    2008-01-01

    The dihydropteridine reductase from D. discoideum has been crystallized. Diffraction data were collected from a rectangular-shaped crystal to 2.16 Å resolution. Dihydropteridine reductase from Dictyostelium discoideum (dicDHPR) can produce d-threo-BH 4 [6R-(1′R,2′R)-5,6,7,8-tetrahydrobiopterin], a stereoisomer of l-erythro-BH 4 , in the last step of tetrahydrobiopterin (BH 4 ) recycling. In this reaction, DHPR uses NADH as a cofactor to reduce quinonoid dihydrobiopterin back to BH 4 . To date, the enzyme has been purified to homogeneity from many sources. In this report, the dicDHPR–NAD complex has been crystallized using the hanging-drop vapour-diffusion method with PEG 3350 as a precipitant. Rectangular-shaped crystals were obtained. Crystals grew to maximum dimensions of 0.4 × 0.6 × 0.1 mm. The crystal belonged to space group P2 1 , with unit-cell parameters a = 49.81, b = 129.90, c = 78.76 Å, β = 100.00°, and contained four molecules in the asymmetric unit, forming two closely interacting dicDHPR–NAD dimers. Diffraction data were collected to 2.16 Å resolution using synchrotron radiation. The crystal structure has been determined using the molecular-replacement method

  16. Cheating by exploitation of developmental prestalk patterning in Dictyostelium discoideum.

    Directory of Open Access Journals (Sweden)

    Anupama Khare

    2010-02-01

    Full Text Available The cooperative developmental system of the social amoeba Dictyostelium discoideum is susceptible to exploitation by cheaters-strains that make more than their fair share of spores in chimerae. Laboratory screens in Dictyostelium have shown that the genetic potential for facultative cheating is high, and field surveys have shown that cheaters are abundant in nature, but the cheating mechanisms are largely unknown. Here we describe cheater C (chtC, a strong facultative cheater mutant that cheats by affecting prestalk differentiation. The chtC gene is developmentally regulated and its mRNA becomes stalk-enriched at the end of development. chtC mutants are defective in maintaining the prestalk cell fate as some of their prestalk cells transdifferentiate into prespore cells, but that defect does not affect gross developmental morphology or sporulation efficiency. In chimerae between wild-type and chtC mutant cells, the wild-type cells preferentially give rise to prestalk cells, and the chtC mutants increase their representation in the spore mass. Mixing chtC mutants with other cell-type proportioning mutants revealed that the cheating is directly related to the prestalk-differentiation propensity of the victim. These findings illustrate that a cheater can victimize cooperative strains by exploiting an established developmental pathway.

  17. Cheating by Exploitation of Developmental Prestalk Patterning in Dictyostelium discoideum

    Science.gov (United States)

    Khare, Anupama; Shaulsky, Gad

    2010-01-01

    The cooperative developmental system of the social amoeba Dictyostelium discoideum is susceptible to exploitation by cheaters—strains that make more than their fair share of spores in chimerae. Laboratory screens in Dictyostelium have shown that the genetic potential for facultative cheating is high, and field surveys have shown that cheaters are abundant in nature, but the cheating mechanisms are largely unknown. Here we describe cheater C (chtC), a strong facultative cheater mutant that cheats by affecting prestalk differentiation. The chtC gene is developmentally regulated and its mRNA becomes stalk-enriched at the end of development. chtC mutants are defective in maintaining the prestalk cell fate as some of their prestalk cells transdifferentiate into prespore cells, but that defect does not affect gross developmental morphology or sporulation efficiency. In chimerae between wild-type and chtC mutant cells, the wild-type cells preferentially give rise to prestalk cells, and the chtC mutants increase their representation in the spore mass. Mixing chtC mutants with other cell-type proportioning mutants revealed that the cheating is directly related to the prestalk-differentiation propensity of the victim. These findings illustrate that a cheater can victimize cooperative strains by exploiting an established developmental pathway. PMID:20195510

  18. A new social gene in Dictyostelium discoideum, chtB

    Directory of Open Access Journals (Sweden)

    Santorelli Lorenzo A

    2013-01-01

    Full Text Available Abstract Background Competitive social interactions are ubiquitous in nature, but their genetic basis is difficult to determine. Much can be learned from single gene knockouts in a eukaryote microbe. The mutants can be competed with the parent to discern the social impact of that specific gene. Dictyostelium discoideum is a social amoeba that exhibits cooperative behavior in the construction of a multicellular fruiting body. It is a good model organism to study the genetic basis of cooperation since it has a sequenced genome and it is amenable to genetic manipulation. When two strains of D. discoideum are mixed, a cheater strain can exploit its social partner by differentiating more spore than its fair share relative to stalk cells. Cheater strains can be generated in the lab or found in the wild and genetic analyses have shown that cheating behavior can be achieved through many pathways. Results We have characterized the knockout mutant chtB, which was isolated from a screen for cheater mutants that were also able to form normal fruiting bodies on their own. When mixed in equal proportions with parental strain cells, chtB mutants contributed almost 60% of the total number of spores. To do so, chtB cells inhibit wild type cells from becoming spores, as indicated by counts and by the wild type cells’ reduced expression of the prespore gene, cotB. We found no obvious fitness costs (morphology, doubling time in liquid medium, spore production, and germination efficiency associated with the cheating ability of the chtB knockout. Conclusions In this study we describe a new gene in D. discoideum, chtB, which when knocked out inhibits the parental strain from producing spores. Moreover, under lab conditions, we did not detect any fitness costs associated with this behavior.

  19. A secreted protein is an endogenous chemorepellant in Dictyostelium discoideum.

    Science.gov (United States)

    Phillips, Jonathan E; Gomer, Richard H

    2012-07-03

    Chemorepellants may play multiple roles in physiological and pathological processes. However, few endogenous chemorepellants have been identified, and how they function is unclear. We found that the autocrine signal AprA, which is produced by growing Dictyostelium discoideum cells and inhibits their proliferation, also functions as a chemorepellant. Wild-type cells at the edge of a colony show directed movement outward from the colony, whereas cells lacking AprA do not. Cells show directed movement away from a source of recombinant AprA and dialyzed conditioned media from wild-type cells, but not dialyzed conditioned media from aprA(-) cells. The secreted protein CfaD, the G protein Gα8, and the kinase QkgA are necessary for the chemorepellant activity of AprA as well as its proliferation-inhibiting activity, whereas the putative transcription factor BzpN is dispensable for the chemorepellant activity of AprA but necessary for inhibition of proliferation. Phospholipase C and PI3 kinases 1 and 2, which are necessary for the activity of at least one other chemorepellant in Dictyostelium, are not necessary for recombinant AprA chemorepellant activity. Starved cells are not repelled by recombinant AprA, suggesting that aggregation-phase cells are not sensitive to the chemorepellant effect. Cell tracking indicates that AprA affects the directional bias of cell movement, but not cell velocity or the persistence of cell movement. Together, our data indicate that the endogenous signal AprA acts as an autocrine chemorepellant for Dictyostelium cells.

  20. Subcellular localization of ammonium transporters in Dictyostelium discoideum

    Directory of Open Access Journals (Sweden)

    Davis Carter T

    2008-12-01

    Full Text Available Abstract Background With the exception of vertebrates, most organisms have plasma membrane associated ammonium transporters which primarily serve to import a source of nitrogen for nutritional purposes. Dictyostelium discoideum has three ammonium transporters, Amts A, B and C. Our present work used fluorescent fusion proteins to determine the cellular localization of the Amts and tested the hypothesis that the transporters mediate removal of ammonia generated endogenously from the elevated protein catabolism common to many protists. Results Using RFP and YFP fusion constructs driven by the actin 15 promoter, we found that the three ammonium transporters were localized on the plasma membrane and on the membranes of subcellular organelles. AmtA and AmtB were localized on the membranes of endolysosomes and phagosomes, with AmtB further localized on the membranes of contractile vacuoles. AmtC also was localized on subcellular organelles when it was stabilized by coexpression with either the AmtA or AmtB fusion transporter. The three ammonium transporters exported ammonia linearly with regard to time during the first 18 hours of the developmental program as revealed by reduced export in the null strains. The fluorescently tagged transporters rescued export when expressed in the null strains, and thus they were functional transporters. Conclusion Unlike ammonium transporters in most organisms, which import NH3/NH4+ as a nitrogen source, those of Dictyostelium export ammonia/ammonium as a waste product from extensive catabolism of exogenously derived and endogenous proteins. Localization on proteolytic organelles and on the neutral contractile vacuole suggests that Dictyostelium ammonium transporters may have unique subcellular functions and play a role in the maintenance of intracellular ammonium distribution. A lack of correlation between the null strain phenotypes and ammonia excretion properties of the ammonium transporters suggests that it is not

  1. Identification and recombinant expression of anandamide hydrolyzing enzyme from Dictyostelium discoideum

    Directory of Open Access Journals (Sweden)

    Neelamegan Dhamodharan

    2012-06-01

    Full Text Available Abstract Background Anandamide (Arachidonoyl ethanolamide is a potent bioactive lipid studied extensively in humans, which regulates several neurobehavioral processes including pain, feeding and memory. Bioactivity is terminated when hydrolyzed into free arachidonic acid and ethanolamine by the enzyme fatty acid amide hydrolase (FAAH. In this study we report the identification of a FAAH homolog from Dictyostelium discoideum and its function to hydrolyze anandamide. Results A putative FAAH DNA sequence coding for a conserved amidase signature motif was identified in the Dictyostelium genome database and the corresponding cDNA was isolated and expressed as an epitope tagged fusion protein in either E.coli or Dictyostelium. Wild type Dictyostelium cells express FAAH throughout their development life cycle and the protein was found to be predominantly membrane associated. Production of recombinant HIS tagged FAAH protein was not supported in E.coli host, but homologous Dictyostelium host was able to produce the same successfully. Recombinant FAAH protein isolated from Dictyostelium was shown to hydrolyze anandamide and related synthetic fatty acid amide substrates. Conclusions This study describes the first identification and characterisation of an anandamide hydrolyzing enzyme from Dictyostelium discoideum, suggesting the potential of Dictyostelium as a simple eukaryotic model system for studying mechanisms of action of any FAAH inhibitors as drug targets.

  2. Chemotaxis to cyclic AMP and folic acid is mediated by different G proteins in Dictyostelium discoideum

    NARCIS (Netherlands)

    Kesbeke, Fanja; Haastert, Peter J.M. van; Wit, René J.W. de; Snaar-Jagalska, B. Ewa

    1990-01-01

    Mutant Frigid A (fgdA) of Dictyostelium discoideum is defective in a functional Gα2 subunit of a G protein and is characterized by a complete blockade of the cyclic AMP-mediated sensory transduction steps, including cyclic AMP relay, chemotaxis and the cyclic GMP response. Folic acid-mediated

  3. Phototaxis during the slug stage of Dictyostelium discoideum: a model study

    NARCIS (Netherlands)

    Marée, A.F.M.; Panfilov, A.V.; Hogeweg, P.

    1999-01-01

    During the slug stage, the cellular slime mould Dictyostelium discoideum moves towards light sources. We have modelled this phototactic behaviour using a hybrid cellular automata/partial differential equation model. In our model, individual amoebae are not able to measure the direction from which

  4. Normal chemotaxis in Dictyostelium discoideum cells with a depolarized plasma membrane potential

    NARCIS (Netherlands)

    Duijn, Bert van; Vogelzang, Sake A.; Ypey, Dirk L.; Molen, Loek G. van der; Haastert, Peter J.M. van

    1990-01-01

    We examined a possible role for the plasma membrane potential in signal transduction during cyclic AMP-induced chemotaxis in the cellular slime mold Dictyostelium discoideum. Chemotaxis, cyclic GMP and cyclic AMP responses in cells with a depolarized membrane potential were measured. Cells can be

  5. Transient Kinetics of a cGMP-dependent cGMP-specific Phosphodiesterase from Dictyostelium discoideum

    NARCIS (Netherlands)

    Haastert, Peter J.M. van; Lookeren Campagne, Michiel M. van

    1984-01-01

    Chemotactic stimulation of Dictyostelium discoideum cells induces a fast transient increase of cGMP levels which reach a peak at 10 s. Prestimulation levels are recovered in ~30 s, which is achieved mainly by the action of a guanosine 3',5'-monophosphate cGMP-specific phosphodiesterase. This enzyme

  6. Regulation of TORC2 complex in Dictyostelium discoideum

    NARCIS (Netherlands)

    Khanna, Ankita

    2016-01-01

    Dictyostelium is an amoeba that lives in the soil where it feeds on bacteria. During scarcity of food, Dictyostelium cells undergo a highly regulated developmental process in which the cells aggregate by chemotaxing towards pulsatile emission of extracellular cAMP from a signaling center; the cells

  7. Arachidonic acid is a chemoattractant for Dictyostelium discoideum ...

    Indian Academy of Sciences (India)

    SEARCHU

    binding proteins and calmodulin-dependent phosphorylation linked to calmodulin-dependent chemotaxis to folic and cAMP in Dictyostelium; Cell Signal 13 575–584. Gerisch G and Hess B 1974 Cyclic-AMP-controlled oscillations in suspended Dictyostelium cells: Their relation to morphogenetic cell interactions; Proc. Natl.

  8. Dictyostelium discoideum as a novel host system to study the interaction between phagocytes and yeasts

    Directory of Open Access Journals (Sweden)

    Barbara Koller

    2016-10-01

    Full Text Available The social amoeba Dictyostelium discoideum is a well-established model organism to study the interaction between bacteria and phagocytes. In contrast, research using D. discoideum as a host model for fungi is rare. We describe a comprehensive study, which uses D. discoideum as a host model system to investigate the interaction with apathogenic (Saccharomyces cerevisiae and pathogenic (Candida sp. yeast. We show that Dictyostelium can be co-cultivated with yeasts on solid media, offering a convenient test to study the interaction between fungi and phagocytes. We demonstrate that a number of D. discoideum mutants increase (atg1-, kil1-, kil2- or decrease (atg6- the ability of the amoebae to predate yeast cells. On the yeast side, growth characteristics, reduced phagocytosis rate, as well as known virulence factors of C. albicans (EFG1, CPH1, HGC1, ICL1 contribute to the resistance of yeast cells against predation by the amoebae. Investigating haploid C. albicans strains, we suggest using the amoebae plate test for screening purposes after random mutagenesis. Finally, we discuss the potential of our adapted amoebae plate test to use D. discoideum for risk assessment of yeast strains.

  9. Functional characterisation of parvulin-type peptidyl prolyl cis-trans isomerase, PinA in Dictyostelium discoideum

    International Nuclear Information System (INIS)

    Haokip, Nemneineng; Naorem, Aruna

    2017-01-01

    Pin1-type parvulins are unique among PPIases that can catalyse an otherwise slow cis-trans isomerisation of phosphorylated peptide bond preceding proline in target proteins. This prolyl isomerisation process can regulate activity, stability and localisation of target proteins and thus control cellular processes like eukaryotic cell proliferation, cell cycle progression and gene regulation. Towards understanding the function of Pin1-type prolyl isomerisation in Dictyostelium discoideum, a slime mould with distinct growth and developmental phases, we identified PinA as a novel Pin1-type parvulin by its ability to complement the temperature sensitivity phenotype associated with a mutation in ESS1 in S. cerevisiae. In D. discoideum, pinA is temporally and spatially regulated during growth and development. PinA is both nuclear as well as cytoplasmic in the growing cells. We further show that loss of pinA (pinA − ) leads to decreased growth rate, reduced spore formation and abnormal prespore-prestalk patterning. We conclude that PinA is required for normal growth as well as development in D. discoideum. - Highlights: • PinA is a bona fide homologue of S. cerevisiae Ess1. • PinA is required for normal cell proliferation of D. discoideum. • PinA is spatially localised in developmental structures. • PinA is important for cell differentiation and patterning.

  10. Inorganic Polyphosphate Is Essential for Salmonella Typhimurium Virulence and Survival in Dictyostelium discoideum

    Directory of Open Access Journals (Sweden)

    Macarena A. Varas

    2018-01-01

    Full Text Available Inorganic polyphosphate (polyP deficiency in enteric bacterial pathogens reduces their ability to invade and establish systemic infections in different hosts. For instance, inactivation of the polyP kinase gene (ppk encoding the enzyme responsible for polyP biosynthesis reduces invasiveness and intracellular survival of Salmonella enterica serovar Typhimurium (S. Typhimurium in epithelial cells and macrophages in vitro. In addition, the virulence in vivo of a S. Typhimurium Δppk mutant is significantly reduced in a murine infection model. In spite of these observations, the role played by polyP during the Salmonella-host interaction is not well understood. The social amoeba Dictyostelium discoideum has proven to be a useful model for studying relevant aspects of the host-pathogen interaction. In fact, many intracellular pathogens can survive within D. discoideum cells using molecular mechanisms also required to survive within macrophages. Recently, we established that S. Typhimurium is able to survive intracellularly in D. discoideum and identified relevant genes linked to virulence that are crucial for this process. The aim of this study was to determine the effect of a polyP deficiency in S. Typhimurium during its interaction with D. discoideum. To do this, we evaluated the intracellular survival of wild-type and Δppk strains of S. Typhimurium in D. discoideum and the ability of these strains to delay the social development of the amoeba. In contrast to the wild-type strain, the Δppk mutant was unable to survive intracellularly in D. discoideum and enabled the social development of the amoeba. Both phenotypes were complemented using a plasmid carrying a copy of the ppk gene. Next, we simultaneously evaluated the proteomic response of both S. Typhimurium and D. discoideum during host-pathogen interaction via global proteomic profiling. The analysis of our results allowed the identification of novel molecular signatures that give insight into

  11. Scanning the available Dictyostelium discoideum proteome for O-linked GlcNAc glycosylation sitesusing neural networks

    DEFF Research Database (Denmark)

    Gupta, Ramneek; Jung, Eva; Gooley, Andrew A

    1999-01-01

    Dictyostelium discoideum has been suggested as a eukaryotic model organism for glycobiology studies. Presently, the characteristics of acceptor sites for the N-acetylglucosaminyl-transferases in Dictyostelium discoideum, which link GlcNAc in an alpha linkage to hydroxyl residues, are largely...... unknown. This motivates the development of a species specific method for prediction of O-linked GlcNAc glycosylation sites in secreted and membrane proteins of D. discoideum. The method presented here employs a jury of artificial neural networks. These networks were trained to recognize the sequence...... context and protein surface accessibility in 39 experimentally determined O-alpha-GlcNAc sites found in D. discoideum glycoproteins expressed in vivo. Cross-validation of the data revealed a correlation in which 97% of the glycosylated and nonglycosylated sites were correctly identified. Based...

  12. Variation, sex, and social cooperation: molecular population genetics of the social amoeba Dictyostelium discoideum.

    Directory of Open Access Journals (Sweden)

    Jonathan M Flowers

    2010-07-01

    Full Text Available Dictyostelium discoideum is a eukaryotic microbial model system for multicellular development, cell-cell signaling, and social behavior. Key models of social evolution require an understanding of genetic relationships between individuals across the genome or possibly at specific genes, but the nature of variation within D. discoideum is largely unknown. We re-sequenced 137 gene fragments in wild North American strains of D. discoideum and examined the levels and patterns of nucleotide variation in this social microbial species. We observe surprisingly low levels of nucleotide variation in D. discoideum across these strains, with a mean nucleotide diversity (pi of 0.08%, and no strong population stratification among North American strains. We also do not find any clear relationship between nucleotide divergence between strains and levels of social dominance and kin discrimination. Kin discrimination experiments, however, show that strains collected from the same location show greater ability to distinguish self from non-self than do strains from different geographic areas. This suggests that a greater ability to recognize self versus non-self may arise among strains that are more likely to encounter each other in nature, which would lead to preferential formation of fruiting bodies with clonemates and may prevent the evolution of cheating behaviors within D. discoideum populations. Finally, despite the fact that sex has rarely been observed in this species, we document a rapid decay of linkage disequilibrium between SNPs, the presence of recombinant genotypes among natural strains, and high estimates of the population recombination parameter rho. The SNP data indicate that recombination is widespread within D. discoideum and that sex as a form of social interaction is likely to be an important aspect of the life cycle.

  13. Characterization of a 1,4-. beta. -D-glucan synthase from Dictyostelium discoideum

    Energy Technology Data Exchange (ETDEWEB)

    Blanton, R.L.

    1992-01-15

    Various aspects of research concerning Dictyostelium discoideum are presented. The initial focus of this project was upon: the characterization of potential probes for the cellulose synthase (antibody and nucleic acid), the determination of the cultural induction conditions of cellulose synthesis, the solubilization of the enzyme activity, the development of a non-inhibitory disruption buffer, the generation and isolation of mutant strains deficient in cellulose synthesis, and the development of the capability to determine the degree of polymerization of the in vitro product. I have briefly summarized our most significant findings with only selected data sets being shown in this report in the interest of brevity.

  14. Identification of Pentatricopeptide Repeat Proteins in the Model Organism Dictyostelium discoideum

    Directory of Open Access Journals (Sweden)

    Sam Manna

    2013-01-01

    Full Text Available Pentatricopeptide repeat (PPR proteins are RNA binding proteins with functions in organelle RNA metabolism. They are found in all eukaryotes but have been most extensively studied in plants. We report on the identification of 12 PPR-encoding genes in the genome of the protist Dictyostelium discoideum, with potential homologs in other members of the same lineage and some predicted novel functions for the encoded gene products in protists. For one of the gene products, we show that it localizes to the mitochondria, and we also demonstrate that antisense inhibition of its expression leads to slower growth, a phenotype associated with mitochondrial dysfunction.

  15. Sociogenomics of self vs. non-self cooperation during development of Dictyostelium discoideum.

    Science.gov (United States)

    Li, Si I; Buttery, Neil J; Thompson, Christopher R L; Purugganan, Michael D

    2014-07-21

    Dictyostelium discoideum, a microbial model for social evolution, is known to distinguish self from non-self and show genotype-dependent behavior during chimeric development. Aside from a small number of cell-cell recognition genes, however, little is known about the genetic basis of self/non-self recognition in this species. Based on the key hypothesis that there should be differential expression of genes if D. discoideum cells were interacting with non-clone mates, we performed transcriptomic profiling study in this species during clonal vs. chimeric development. The transcriptomic profiles of D. discoideum cells in clones vs. different chimeras were compared at five different developmental stages using a customized microarray. Effects of chimerism on global transcriptional patterns associated with social interactions were observed. We find 1,759 genes significantly different between chimera and clone, 1,144 genes associated significant strain differences, and 6,586 genes developmentally regulated over time. Principal component analysis showed a small amount of the transcriptional variance to chimerism-related factors (Chimerism: 0.18%, Chimerism × Timepoint: 0.03%). There are 162 genes specifically regulated under chimeric development, with continuous small differences between chimera vs. clone over development. Almost 60% of chimera-associated differential genes were differentially expressed at the 4 h aggregate stage, which corresponds to the initial transition of D. discoideum from solitary life to a multicellular phase. A relatively small proportion of over-all variation in gene expression is explained by differences between chimeric and clonal development. The relatively small modifications in gene expression associated with chimerism is compatible with the high level of cooperation observed among different strains of D. discoideum; cells of distinct genetic backgrounds will co-aggregate indiscriminately and co-develop into fruiting bodies. Chimeric

  16. Caffeine sensitive repair and mutation induction in UV- or γ-ray-irradiated Dictyostelium discoideum

    International Nuclear Information System (INIS)

    Kanishi, Nobuji; Kinjo, Yasuhito; Watanabe, Makoto.

    1990-01-01

    It seems that certain kinds of chemical substances increase the distortion in molecules, change the high order microstructures of nuclei and chromosomes, and exert large variation to the function of repairing the damage of genes due to radiation and others, by coupling with DNA, protein or enzyme system. It has been well known that caffeine is one of such compounds, and by coupling with DNA, it increases the damage due to ultraviolet ray and gives the action of obstructing repair in addition to the action of inducing the abnormality of chromosomes and mutation. Dictyostelium discoideum has the simplest nuclear structure, and shows extremely high resistance to radiation by its high restoration ability. The authors have advanced the research by paying attention to its characteristics, and comparing the Dictyostelium discoideum as one model system with the lymphocyte system of higher animals. This time, the authors analyzed the characteristics of two kinds of sensitivity repair process of caffeine, and investigated into their relation with the occurrence of mutation. The experimental method and the results are reported. (K.I.)

  17. Caffeine sensitive repair and mutation induction in UV- or. gamma. -ray-irradiated Dictyostelium discoideum

    Energy Technology Data Exchange (ETDEWEB)

    Kanishi, Nobuji (Tokyo Metropolitan Research Lab. of Public Health (Japan)); Kinjo, Yasuhito; Watanabe, Makoto

    1990-01-01

    It seems that certain kinds of chemical substances increase the distortion in molecules, change the high order microstructures of nuclei and chromosomes, and exert large variation to the function of repairing the damage of genes due to radiation and others, by coupling with DNA, protein or enzyme system. It has been well known that caffeine is one of such compounds, and by coupling with DNA, it increases the damage due to ultraviolet ray and gives the action of obstructing repair in addition to the action of inducing the abnormality of chromosomes and mutation. Dictyostelium discoideum has the simplest nuclear structure, and shows extremely high resistance to radiation by its high restoration ability. The authors have advanced the research by paying attention to its characteristics, and comparing the Dictyostelium discoideum as one model system with the lymphocyte system of higher animals. This time, the authors analyzed the characteristics of two kinds of sensitivity repair process of caffeine, and investigated into their relation with the occurrence of mutation. The experimental method and the results are reported. (K.I.).

  18. Mitochondrial Stress Tests Using Seahorse Respirometry on Intact Dictyostelium discoideum Cells.

    Science.gov (United States)

    Lay, Sui; Sanislav, Oana; Annesley, Sarah J; Fisher, Paul R

    2016-01-01

    Mitochondria not only play a critical and central role in providing metabolic energy to the cell but are also integral to the other cellular processes such as modulation of various signaling pathways. These pathways affect many aspects of cell physiology, including cell movement, growth, division, differentiation, and death. Mitochondrial dysfunction which affects mitochondrial bioenergetics and causes oxidative phosphorylation defects can thus lead to altered cellular physiology and manifest in disease. The assessment of the mitochondrial bioenergetics can thus provide valuable insights into the physiological state, and the alterations to the state of the cells. Here, we describe a method to successfully use the Seahorse XF(e)24 Extracellular Flux Analyzer to assess the mitochondrial respirometry of the cellular slime mold Dictyostelium discoideum.

  19. An Autocrine Proliferation Repressor Regulates Dictyostelium discoideum Proliferation and Chemorepulsion Using the G Protein-Coupled Receptor GrlH

    OpenAIRE

    Yu Tang; Yuantai Wu; Sarah E. Herlihy; Francisco J. Brito-Aleman; Jose H. Ting; Chris Janetopoulos; Richard H. Gomer; Scott D. Emr

    2018-01-01

    In eukaryotic microbes, little is known about signals that inhibit the proliferation of the cells that secrete the signal, and little is known about signals (chemorepellents) that cause cells to move away from the source of the signal. Autocrine proliferation repressor protein A (AprA) is a protein secreted by the eukaryotic microbe Dictyostelium discoideum. AprA is a chemorepellent for and inhibits the proliferation of D. discoideum. We previously found that cells sense AprA using G proteins...

  20. Xpf and not the Fanconi anaemia proteins or Rev3 accounts for the extreme resistance to cisplatin in Dictyostelium discoideum.

    Directory of Open Access Journals (Sweden)

    Xiao-Yin Zhang

    2009-09-01

    Full Text Available Organisms like Dictyostelium discoideum, often referred to as DNA damage "extremophiles", can survive exposure to extremely high doses of radiation and DNA crosslinking agents. These agents form highly toxic DNA crosslinks that cause extensive DNA damage. However, little is known about how Dictyostelium and the other "extremophiles" can tolerate and repair such large numbers of DNA crosslinks. Here we describe a comprehensive genetic analysis of crosslink repair in Dictyostelium discoideum. We analyse three gene groups that are crucial for a replication-coupled repair process that removes DNA crosslinks in higher eukarya: The Fanconi anaemia pathway (FA, translesion synthesis (TLS, and nucleotide excision repair. Gene disruption studies unexpectedly reveal that the FA genes and the TLS enzyme Rev3 play minor roles in tolerance to crosslinks in Dictyostelium. However, disruption of the Xpf nuclease subcomponent results in striking hypersensitivity to crosslinks. Genetic interaction studies reveal that although Xpf functions with FA and TLS gene products, most Xpf mediated repair is independent of these two gene groups. These results suggest that Dictyostelium utilises a distinct Xpf nuclease-mediated repair process to remove crosslinked DNA. Other DNA damage-resistant organisms and chemoresistant cancer cells might adopt a similar strategy to develop resistance to DNA crosslinking agents.

  1. Effects of Nickel, Chlorpyrifos and Their Mixture on the Dictyostelium discoideum Proteome

    Science.gov (United States)

    Boatti, Lara; Robotti, Elisa; Marengo, Emilio; Viarengo, Aldo; Marsano, Francesco

    2012-01-01

    Mixtures of chemicals can have additive, synergistic or antagonistic interactions. We investigated the effects of the exposure to nickel, the organophosphate insecticide chlorpyrifos at effect concentrations (EC) of 25% and 50% and their binary mixture (Ec25 + EC25) on Dictyostelium discoideum amoebae based on lysosomal membrane stability (LMS). We treated D. discoideum with these compounds under controlled laboratory conditions and evaluated the changes in protein levels using a two-dimensional gel electrophoresis (2DE) proteomic approach. Nickel treatment at EC25 induced changes in 14 protein spots, 12 of which were down-regulated. Treatment with nickel at EC50 resulted in changes in 15 spots, 10 of which were down-regulated. Treatment with chlorpyrifos at EC25 induced changes in six spots, all of which were down-regulated; treatment with chlorpyrifos at EC50 induced changes in 13 spots, five of which were down-regulated. The mixture corresponding to EC25 of each compound induced changes in 19 spots, 13 of which were down-regulated. The data together reveal that a different protein expression signature exists for each treatment, and that only a few proteins are modulated in multiple different treatments. For a simple binary mixture, the proteomic response does not allow for the identification of each toxicant. The protein spots that showed significant differences were identified by mass spectrometry, which revealed modulations of proteins involved in metal detoxification, stress adaptation, the oxidative stress response and other cellular processes. PMID:23443088

  2. Nucleocytoplasmic protein translocation during mitosis in the social amoebozoan Dictyostelium discoideum.

    Science.gov (United States)

    O'Day, Danton H; Budniak, Aldona

    2015-02-01

    Mitosis is a fundamental and essential life process. It underlies the duplication and survival of all cells and, as a result, all eukaryotic organisms. Since uncontrolled mitosis is a dreaded component of many cancers, a full understanding of the process is critical. Evolution has led to the existence of three types of mitosis: closed, open, and semi-open. The significance of these different mitotic species, how they can lead to a full understanding of the critical events that underlie the asexual duplication of all cells, and how they may generate new insights into controlling unregulated cell division remains to be determined. The eukaryotic microbe Dictyostelium discoideum has proved to be a valuable biomedical model organism. While it appears to utilize closed mitosis, a review of the literature suggests that it possesses a form of mitosis that lies in the middle between truly open and fully closed mitosis-it utilizes a form of semi-open mitosis. Here, the nucleocytoplasmic translocation patterns of the proteins that have been studied during mitosis in the social amoebozoan D. discoideum are detailed followed by a discussion of how some of them provide support for the hypothesis of semi-open mitosis. © 2014 The Authors. Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.

  3. Influence of fast advective flows on pattern formation of Dictyostelium discoideum

    Science.gov (United States)

    Bae, Albert; Zykov, Vladimir; Bodenschatz, Eberhard

    2018-01-01

    We report experimental and numerical results on pattern formation of self-organizing Dictyostelium discoideum cells in a microfluidic setup under a constant buffer flow. The external flow advects the signaling molecule cyclic adenosine monophosphate (cAMP) downstream, while the chemotactic cells attached to the solid substrate are not transported with the flow. At high flow velocities, elongated cAMP waves are formed that cover the whole length of the channel and propagate both parallel and perpendicular to the flow direction. While the wave period and transverse propagation velocity are constant, parallel wave velocity and the wave width increase linearly with the imposed flow. We also observe that the acquired wave shape is highly dependent on the wave generation site and the strength of the imposed flow. We compared the wave shape and velocity with numerical simulations performed using a reaction-diffusion model and found excellent agreement. These results are expected to play an important role in understanding the process of pattern formation and aggregation of D. discoideum that may experience fluid flows in its natural habitat. PMID:29590179

  4. Binding and assembly of actin filaments by plasma membranes from dictyostelium discoideum

    International Nuclear Information System (INIS)

    Schwartz, M.A.; Luna, E.J.

    1986-01-01

    The binding of native, 125 I-Bolton-Hunter-labeled actin to purified Dictyostelium discoideum plasma membranes was measured using a sedimentation assay. Binding was saturable only in the presence of the actin capping protein, gelsolin. The binding curves were sigmoidal, indicating positive cooperativity at low actin concentrations. This cooperativity appeared to be due to actin-actin associations during polymerization, since phalloidin converted the curve to a hyperbolic shape. This membrane-bound actin stained with rhodamine-phalloidin and was cross-linked by m-maleimidobenzoyl succinimide ester, a bifunctional cross-linker, into multimers with the same pattern observed for cross-linked F-actin. The authors conclude that D. discoideum plasma membranes bind actin specifically and saturably and that these membranes organize actin into filaments below the normal critical concentration for polymerization. This interaction probably occurs between multiple binding sites on the membrane and the side of the actin filament, and may be related to the clustering of membrane proteins

  5. Evaluating Different Virulence Traits of Klebsiella pneumoniae Using Dictyostelium discoideum and Zebrafish Larvae as Host Models

    Directory of Open Access Journals (Sweden)

    Andrés E. Marcoleta

    2018-02-01

    Full Text Available Multiresistant and invasive hypervirulent Klebsiella pneumoniae strains have become one of the most urgent bacterial pathogen threats. Recent analyses revealed a high genomic plasticity of this species, harboring a variety of mobile genetic elements associated with virulent strains, encoding proteins of unknown function whose possible role in pathogenesis have not been addressed. K. pneumoniae virulence has been studied mainly in animal models such as mice and pigs, however, practical, financial, ethical and methodological issues limit the use of mammal hosts. Consequently, the development of simple and cost-effective experimental approaches with alternative host models is needed. In this work we described the use of both, the social amoeba and professional phagocyte Dictyostelium discoideum and the fish Danio rerio (zebrafish as surrogate host models to study K. pneumoniae virulence. We compared three K. pneumoniae clinical isolates evaluating their resistance to phagocytosis, intracellular survival, lethality, intestinal colonization, and innate immune cells recruitment. Optical transparency of both host models permitted studying the infective process in vivo, following the Klebsiella-host interactions through live-cell imaging. We demonstrated that K. pneumoniae RYC492, but not the multiresistant strains 700603 and BAA-1705, is virulent to both host models and elicits a strong immune response. Moreover, this strain showed a high resistance to phagocytosis by D. discoideum, an increased ability to form biofilms and a more prominent and irregular capsule. Besides, the strain 700603 showed the unique ability to replicate inside amoeba cells. Genomic comparison of the K. pneumoniae strains showed that the RYC492 strain has a higher overall content of virulence factors although no specific genes could be linked to its phagocytosis resistance, nor to the intracellular survival observed for the 700603 strain. Our results indicate that both zebrafish

  6. A retinoblastoma orthologue is required for the sensing of a chalone in Dictyostelium discoideum.

    Science.gov (United States)

    Bakthavatsalam, Deenadayalan; White, Michael J V; Herlihy, Sarah E; Phillips, Jonathan E; Gomer, Richard H

    2014-03-01

    Retinoblastoma-like proteins regulate cell differentiation and inhibit cell proliferation. The Dictyostelium discoideum retinoblastoma orthologue RblA affects the differentiation of cells during multicellular development, but it is unclear whether RblA has a significant effect on Dictyostelium cell proliferation, which is inhibited by the secreted proteins AprA and CfaD. We found that rblA⁻ cells in shaking culture proliferate to a higher density, die faster after reaching stationary density, and, after starvation, have a lower spore viability than wild-type cells, possibly because in shaking culture, rblA⁻ cells have both increased cytokinesis and lower extracellular accumulation of CfaD. However, rblA⁻ cells have abnormally slow proliferation on bacterial lawns. Recombinant AprA inhibits the proliferation of wild-type cells but not that of rblA⁻ cells, whereas CfaD inhibits the proliferation of both wild-type cells and rblA⁻ cells. Similar to aprA⁻ cells, rblA⁻ cells have a normal mass and protein accumulation rate on a per-nucleus basis, indicating that RblA affects cell proliferation but not cell growth. AprA also functions as a chemorepellent, and RblA is required for proper AprA chemorepellent activity despite the fact that RblA does not affect cell speed. Together, our data indicate that an autocrine proliferation-inhibiting factor acts through RblA to regulate cell density in Dictyostelium, suggesting that such factors may signal through retinoblastoma-like proteins to control the sizes of structures such as developing organs or tumors.

  7. A RabGAP regulates life-cycle duration via trimeric G-protein cascades in Dictyostelium discoideum.

    Directory of Open Access Journals (Sweden)

    Hidekazu Kuwayama

    Full Text Available BACKGROUND: The life-cycle of cellular slime molds comprises chronobiologically regulated processes. During the growth phase, the amoeboid cells proliferate at a definite rate. Upon starvation, they synthesize cAMP as both first and second messengers in signalling pathways and form aggregates, migrating slugs, and fruiting bodies, consisting of spores and stalk cells, within 24 h. In Dictyostelium discoideum, because most growth-specific events cease during development, proliferative and heterochronic mutations are not considered to be interrelated and no genetic factor governing the entire life-cycle duration has ever been identified. METHODOLOGY/PRINCIPAL FINDINGS: Using yeast 2-hybrid library screening, we isolated a Dictyostelium discoideum RabGAP, Dd Rbg-3, as a candidate molecule by which the Dictyostelium Gα2 subunit directs its effects. Rab GTPase-activating protein, RabGAP, acts as a negative regulator of Rab small GTPases, which orchestrate the intracellular membrane trafficking involved in cell proliferation. Deletion mutants of Dd rbg-3 exhibited an increased growth rate and a shortened developmental period, while an overexpression mutant demonstrated the opposite effects. We also show that Dd Rbg-3 interacts with 2 Gα subunits in an activity-dependent manner in vitro. Furthermore, both human and Caenorhabditis elegans rbg-3 homologs complemented the Dd rbg-3-deletion phenotype in D. discoideum, indicating that similar pathways may be generally conserved in multicellular organisms. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that Dd Rbg-3 acts as a key element regulating the duration of D. discoideum life-span potentially via trimeric G-protein cascades.

  8. Cytochemical study of the nucleolus of the slime mold Dictyostelium discoideum

    International Nuclear Information System (INIS)

    Benichou, J.C.; Quiviger, B.; Ryter, A.

    1983-01-01

    The nucleus of the slime mold Dictyostelium discoideum is characterized by the presence of several large dense masses which are all in tight contact with the nuclear membrane. These dense masses, considered as nucleoli, present a rather homogeneous texture, in which dense chromatin, fibrillar, and granular material are not easily detected. The autoradiographic study of [ 3 H]uridine pulse-labeled cells showed that the majority of the silver grains were located inside these masses. The use of EDTA regressive-staining, acetylation and enzymatic digestion indicated that they are mostly composed of RNP and are totally devoid of dense chromatin as the rest of the nucleus is. After treatment with actinomycin D, fibrillar and granular material segregated but no chromatin could be found. All these observations confirmed that the dense masses correspond to nucleoli despite their peculiar ultrastructure. It can also be concluded that this type of nucleoli cannot be considered as a taxonomic character of the slime molds because it does not exist in all slime molds and was observed in some dinoflagellates, and ascomycetes

  9. The human homologue of Dictyostelium discoideum phg1A is expressed by human metastatic melanoma cells.

    Science.gov (United States)

    Lozupone, Francesco; Perdicchio, Maurizio; Brambilla, Daria; Borghi, Martina; Meschini, Stefania; Barca, Stefano; Marino, Maria Lucia; Logozzi, Mariantonia; Federici, Cristina; Iessi, Elisabetta; de Milito, Angelo; Fais, Stefano

    2009-12-01

    Tumour cannibalism is a characteristic of malignancy and metastatic behaviour. This atypical phagocytic activity is a crucial survival option for tumours in conditions of low nutrient supply, and has some similarities to the phagocytic activity of unicellular microorganisms. In fact, Dictyostelium discoideum has been used widely as a model to study phagocytosis. Recently, phg1A has been described as a protein that is primarily involved in the phagocytic process of this microorganism. The closest human homologue to phg1A is transmembrane 9 superfamily protein member 4 (TM9SF4). Here, we report that TM9SF4 is highly expressed in human malignant melanoma cells deriving from metastatic lesions, whereas it is undetectable in healthy human tissues and cells. TM9SF4 is predominantly expressed in acidic vesicles of melanoma cells, in which it co-localizes with the early endosome antigens Rab5 and early endosome antigen 1. TM9SF4 silencing induced marked inhibition of cannibal activity, which is consistent with a derangement of intracellular pH gradients, with alkalinization of acidic vesicles and acidification of the cell cytosol. We propose TM9SF4 as a new marker of malignancy, representing a potential new target for anti-tumour strategies with a specific role in tumour cannibalism and in the establishment of a metastatic phenotype.

  10. Inhibitors of Mycobacterium marinum virulence identified in a Dictyostelium discoideum host model.

    Directory of Open Access Journals (Sweden)

    Hajer Ouertatani-Sakouhi

    Full Text Available Tuberculosis remains one of the major threats to public health worldwide. Given the prevalence of multi drug resistance (MDR in Mycobacterium tuberculosis strains, there is a strong need to develop new anti-mycobacterial drugs with modes of action distinct from classical antibiotics. Inhibitors of mycobacterial virulence might target new molecular processes and may represent a potential new therapeutic alternative. In this study, we used a Dictyostelium discoideum host model to assess virulence of Mycobacterium marinum and to identify compounds inhibiting mycobacterial virulence. Among 9995 chemical compounds, we selected 12 inhibitors of mycobacterial virulence that do not inhibit mycobacterial growth in synthetic medium. Further analyses revealed that 8 of them perturbed functions requiring an intact mycobacterial cell wall such as sliding motility, bacterial aggregation or cell wall permeability. Chemical analogs of two compounds were analyzed. Chemical modifications altered concomitantly their effect on sliding motility and on mycobacterial virulence, suggesting that the alteration of the mycobacterial cell wall caused the loss of virulence. We characterized further one of the selected compounds and found that it inhibited the ability of mycobacteria to replicate in infected cells. Together these results identify new antimycobacterial compounds that represent new tools to unravel the molecular mechanisms controlling mycobacterial pathogenicity. The isolation of compounds with anti-virulence activity is the first step towards developing new antibacterial treatments.

  11. Cooperation induces other cooperation: Fruiting bodies promote the evolution of macrocysts in Dictyostelium discoideum.

    Science.gov (United States)

    Shibasaki, Shota; Shirokawa, Yuka; Shimada, Masakazu

    2017-05-21

    Biological studies of the evolution of cooperation are challenging because this process is vulnerable to cheating. Many mechanisms, including kin discrimination, spatial structure, or by-products of self-interested behaviors, can explain this evolution. Here we propose that the evolution of cooperation can be induced by other cooperation. To test this idea, we used a model organism Dictyostelium discoideum because it exhibits two cooperative dormant phases, the fruiting body and the macrocyst. In both phases, the same chemoattractant, cyclic AMP (cAMP), is used to collect cells. This common feature led us to hypothesize that the evolution of macrocyst formation would be induced by coexistence with fruiting bodies. Before forming a mathematical model, we confirmed that macrocysts coexisted with fruiting bodies, at least under laboratory conditions. Next, we analyzed our evolutionary game theory-based model to investigate whether coexistence with fruiting bodies would stabilize macrocyst formation. The model suggests that macrocyst formation represents an evolutionarily stable strategy and a global invader strategy under this coexistence, but is unstable if the model ignores the fruiting body formation. This result indicates that the evolution of macrocyst formation and maintenance is attributable to coexistence with fruiting bodies. Therefore, macrocyst evolution can be considered as an example of evolution of cooperation induced by other cooperation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. RNA synthesis during germination of UV-irradiated Dictyostelium discoideum spores

    International Nuclear Information System (INIS)

    Okaichi, Kumio

    1987-01-01

    UV irradiation to the spores of Dictyostelium discoideum NC4 resulted in a more prolonged delay of amoeba-emergence from swollen spores with increasing UV fluence. During the germination, an inhibition of total RNA synthesis and a shift of stage of maximum RNA synthesis to the later period were observed. The maximum poly(A) + RNA synthetic activity was found on an early stage of amoeba-emergence prior about 1 h to the beginning of rRNA synthesis in unirradiated spore germination; but, in UV-irradiated spore germination, the stage of maximum poly(A) + RNA synthesis shifted to the later stage of germination with increasing UV fluence. A decreased synthesis of poly(A) + RNA and a severe inhibition of rRNA synthesis were observed on UV-irradiated and germinated spores, but no significant inhibition of 4 - 5 S RNA synthesis was detected. Actinomycin D suppressed almost completely the rRNA synthesis of emerged amoebae but the drug apparently did not affect the emergence of amoebae at any stage of germination. It was postulated that the delay of amoeba-emergence in UV-irradiated spore must be mainly due to the shift of the stage of maximum synthesis of poly(A) + RNA to the later stage of germination. (author)

  13. The rate and effects of spontaneous mutation on fitness traits in the social amoeba, Dictyostelium discoideum.

    Science.gov (United States)

    Hall, David W; Fox, Sara; Kuzdzal-Fick, Jennie J; Strassmann, Joan E; Queller, David C

    2013-07-08

    We performed a mutation accumulation (MA) experiment in the social amoeba Dictyostelium discoideum to estimate the rate and distribution of effects of spontaneous mutations affecting eight putative fitness traits. We found that the per-generation mutation rate for most fitness components is 0.0019 mutations per haploid genome per generation or larger. This rate is an order of magnitude higher than estimates for fitness components in the unicellular eukaryote Saccharomyces cerevisiae, even though the base-pair substitution rate is two orders of magnitude lower. The high rate of fitness-altering mutations observed in this species may be partially explained by a large mutational target relative to S. cerevisiae. Fitness-altering mutations also may occur primarily at simple sequence repeats, which are common throughout the genome, including in coding regions, and may represent a target that is particularly likely to give fitness effects upon mutation. The majority of mutations had deleterious effects on fitness, but there was evidence for a substantial fraction, up to 40%, being beneficial for some of the putative fitness traits. Competitive ability within the multicellular slug appears to be under weak directional selection, perhaps reflecting the fact that slugs are sometimes, but not often, comprised of multiple clones in nature. Evidence for pleiotropy among fitness components across MA lines was absent, suggesting that mutations tend to act on single fitness components.

  14. Overexpression of TOR (target of rapamycin) inhibits cell proliferation in Dictyostelium discoideum.

    Science.gov (United States)

    Swer, Pynskhem Bok; Mishra, Himanshu; Lohia, Rakhee; Saran, Shweta

    2016-05-01

    TOR (target of rapamycin) protein kinase acts as a central controller of cell growth and development of an organism. Present study was undertaken to find the expression pattern and role of TOR during growth and development of Dictyostelium discoideum. Failures to generate either knockout and/or knockdown mutants indicate that interference with its levels led to cellular defects. Thus, the effects of TOR (DDB_G0281569) overexpression specifically, cells expressing Dd(Δ211-TOR)-Eyfp mutant was analyzed. Elevated expression of (Δ211-TOR)-Eyfp reduced both cell size and cell proliferation. DdTOR was found to be closer to fungus. mRNA level of TOR was found maximally in the freshly starved/aggregate cells that gradually declined. This was also strengthened by the expression patterns observed by in situ and the analysis of β-galactosidase reporter driven by the putative TOR promoter. The TOR protein was found to be highest at the aggregate stage. The fusion protein, (Δ211-TOR)-Eyfp was localized to the cell membrane, cytosol, and the nucleus. We suggest, DdTOR to be an essential protein and high TOR expression inhibits cell proliferation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Yersinia outer protein YopE affects the actin cytoskeleton in Dictyostelium discoideum through targeting of multiple Rho family GTPases

    LENUS (Irish Health Repository)

    Vlahou, Georgia

    2009-07-14

    Abstract Background All human pathogenic Yersinia species share a virulence-associated type III secretion system that translocates Yersinia effector proteins into host cells to counteract infection-induced signaling responses and prevent phagocytosis. Dictyostelium discoideum has been recently used to study the effects of bacterial virulence factors produced by internalized pathogens. In this study we explored the potential of Dictyostelium as model organism for analyzing the effects of ectopically expressed Yersinia outer proteins (Yops). Results The Yersinia pseudotuberculosis virulence factors YopE, YopH, YopM and YopJ were expressed de novo within Dictyostelium and their effects on growth in axenic medium and on bacterial lawns were analyzed. No severe effect was observed for YopH, YopJ and YopM, but expression of YopE, which is a GTPase activating protein for Rho GTPases, was found to be highly detrimental. GFP-tagged YopE expressing cells had less conspicuous cortical actin accumulation and decreased amounts of F-actin. The actin polymerization response upon cAMP stimulation was impaired, although chemotaxis was unaffected. YopE also caused reduced uptake of yeast particles. These alterations are probably due to impaired Rac1 activation. We also found that YopE predominantly associates with intracellular membranes including the Golgi apparatus and inhibits the function of moderately overexpressed RacH. Conclusion The phenotype elicited by YopE in Dictyostelium can be explained, at least in part, by inactivation of one or more Rho family GTPases. It further demonstrates that the social amoeba Dictyostelium discoideum can be used as an efficient and easy-to-handle model organism in order to analyze the function of a translocated GAP protein of a human pathogen.

  16. Transcriptional down-regulation and rRNA cleavage in Dictyostelium discoideum mitochondria during Legionella pneumophila infection.

    Directory of Open Access Journals (Sweden)

    Chenyu Zhang

    2009-05-01

    Full Text Available Bacterial pathogens employ a variety of survival strategies when they invade eukaryotic cells. The amoeba Dictyostelium discoideum is used as a model host to study the pathogenic mechanisms that Legionella pneumophila, the causative agent of Legionnaire's disease, uses to kill eukaryotic cells. Here we show that the infection of D. discoideum by L. pneumophila results in a decrease in mitochondrial messenger RNAs, beginning more than 8 hours prior to detectable host cell death. These changes can be mimicked by hydrogen peroxide treatment, but not by other cytotoxic agents. The mitochondrial large subunit ribosomal RNA (LSU rRNA is also cleaved at three specific sites during the course of infection. Two LSU rRNA fragments appear first, followed by smaller fragments produced by additional cleavage events. The initial LSU rRNA cleavage site is predicted to be on the surface of the large subunit of the mitochondrial ribosome, while two secondary sites map to the predicted interface with the small subunit. No LSU rRNA cleavage was observed after exposure of D. discoideum to hydrogen peroxide, or other cytotoxic chemicals that kill cells in a variety of ways. Functional L. pneumophila type II and type IV secretion systems are required for the cleavage, establishing a correlation between the pathogenesis of L. pneumophila and D. discoideum LSU rRNA destruction. LSU rRNA cleavage was not observed in L. pneumophila infections of Acanthamoeba castellanii or human U937 cells, suggesting that L. pneumophila uses distinct mechanisms to interrupt metabolism in different hosts. Thus, L. pneumophila infection of D. discoideum results in dramatic decrease of mitochondrial RNAs, and in the specific cleavage of mitochondrial rRNA. The predicted location of the cleavage sites on the mitochondrial ribosome suggests that rRNA destruction is initiated by a specific sequence of events. These findings suggest that L. pneumophila specifically disrupts mitochondrial

  17. Characterization of PEBBLEs as a Tool for Real-Time Measurement of Dictyostelium discoideum Endosomal pH

    Directory of Open Access Journals (Sweden)

    Everett Moding

    2009-01-01

    Full Text Available The measurement of intracellular ion concentration change is important for understanding the cellular mechanisms for communication. Recently developed nanosensors, (Photonic Explorers for Biomedical use with Biologically Localized Embedding PEBBLEs, have a number of advantages for measuring ions in cells over established methods using microelectrodes, unbound fluorescent dyes, or NMR. PEBBLE sensors have been shown to work in principle for measuring dynamic ion changes, but few in vivo applications have been demonstrated. We modified the protocol for the fabrication of pH sensing PEBBLEs and developed a protocol for the utilization of these sensors for the monitoring of dynamic pH changes in the endosomes of slime mold Dictyostelium discoideum (D. discoideum. Oregon Green 514-CdSe Quantum Dot PEBBLEs were used to measure real-time pH inside D. discoideum endosomes during cAMP stimulation. Endosomal pH was shown to decrease during cAMP signaling, demonstrating a movement of protons into the endosomes of D. discoideum amoebae.

  18. Curcumin inhibits development and cell adhesion in Dictyostelium discoideum: Implications for YakA signaling and GST enzyme function

    Energy Technology Data Exchange (ETDEWEB)

    Garige, Mamatha; Walters, Eric, E-mail: ewalters@howard.edu

    2015-11-13

    The molecular basis for nutraceutical properties of the polyphenol curcumin (Curcuma longa, Turmeric) is complex, affecting multiple factors that regulate cell signaling and homeostasis. Here, we report the effect of curcumin on cellular and developmental mechanisms in the eukaryotic model, Dictyostelium discoideum. Dictyostelium proliferation was inhibited in the presence of curcumin, which also suppressed the prestarvation marker, discoidin I, members of the yakA-mediated developmental signaling pathway, and expression of the extracellular matrix/cell adhesion proteins (DdCAD and csA). This resulted in delayed chemotaxis, adhesion, and development of the organism. In contrast to the inhibitory effects on developmental genes, curcumin induced gstA gene expression, overall GST activity, and generated production of reactive oxygen species. These studies expand our knowledge of developmental and biochemical signaling influenced by curcumin, and lends greater consideration of GST enzyme function in eukaryotic cell signaling, development, and differentiation.

  19. Curcumin inhibits development and cell adhesion in Dictyostelium discoideum: Implications for YakA signaling and GST enzyme function

    International Nuclear Information System (INIS)

    Garige, Mamatha; Walters, Eric

    2015-01-01

    The molecular basis for nutraceutical properties of the polyphenol curcumin (Curcuma longa, Turmeric) is complex, affecting multiple factors that regulate cell signaling and homeostasis. Here, we report the effect of curcumin on cellular and developmental mechanisms in the eukaryotic model, Dictyostelium discoideum. Dictyostelium proliferation was inhibited in the presence of curcumin, which also suppressed the prestarvation marker, discoidin I, members of the yakA-mediated developmental signaling pathway, and expression of the extracellular matrix/cell adhesion proteins (DdCAD and csA). This resulted in delayed chemotaxis, adhesion, and development of the organism. In contrast to the inhibitory effects on developmental genes, curcumin induced gstA gene expression, overall GST activity, and generated production of reactive oxygen species. These studies expand our knowledge of developmental and biochemical signaling influenced by curcumin, and lends greater consideration of GST enzyme function in eukaryotic cell signaling, development, and differentiation.

  20. Regulation of Spatiotemporal Patterns by Biological Variability: General Principles and Applications to Dictyostelium discoideum.

    Directory of Open Access Journals (Sweden)

    Miriam Grace

    2015-11-01

    Full Text Available Spatiotemporal patterns often emerge from local interactions in a self-organizing fashion. In biology, the resulting patterns are also subject to the influence of the systematic differences between the system's constituents (biological variability. This regulation of spatiotemporal patterns by biological variability is the topic of our review. We discuss several examples of correlations between cell properties and the self-organized spatiotemporal patterns, together with their relevance for biology. Our guiding, illustrative example will be spiral waves of cAMP in a colony of Dictyostelium discoideum cells. Analogous processes take place in diverse situations (such as cardiac tissue, where spiral waves occur in potentially fatal ventricular fibrillation so a deeper understanding of this additional layer of self-organized pattern formation would be beneficial to a wide range of applications. One of the most striking differences between pattern-forming systems in physics or chemistry and those in biology is the potential importance of variability. In the former, system components are essentially identical with random fluctuations determining the details of the self-organization process and the resulting patterns. In biology, due to variability, the properties of potentially very few cells can have a driving influence on the resulting asymptotic collective state of the colony. Variability is one means of implementing a few-element control on the collective mode. Regulatory architectures, parameters of signaling cascades, and properties of structure formation processes can be "reverse-engineered" from observed spatiotemporal patterns, as different types of regulation and forms of interactions between the constituents can lead to markedly different correlations. The power of this biology-inspired view of pattern formation lies in building a bridge between two scales: the patterns as a collective state of a very large number of cells on the one hand

  1. Whole genome sequencing of mutation accumulation lines reveals a low mutation rate in the social amoeba Dictyostelium discoideum.

    Directory of Open Access Journals (Sweden)

    Gerda Saxer

    Full Text Available Spontaneous mutations play a central role in evolution. Despite their importance, mutation rates are some of the most elusive parameters to measure in evolutionary biology. The combination of mutation accumulation (MA experiments and whole-genome sequencing now makes it possible to estimate mutation rates by directly observing new mutations at the molecular level across the whole genome. We performed an MA experiment with the social amoeba Dictyostelium discoideum and sequenced the genomes of three randomly chosen lines using high-throughput sequencing to estimate the spontaneous mutation rate in this model organism. The mitochondrial mutation rate of 6.76×10(-9, with a Poisson confidence interval of 4.1×10(-9 - 9.5×10(-9, per nucleotide per generation is slightly lower than estimates for other taxa. The mutation rate estimate for the nuclear DNA of 2.9×10(-11, with a Poisson confidence interval ranging from 7.4×10(-13 to 1.6×10(-10, is the lowest reported for any eukaryote. These results are consistent with low microsatellite mutation rates previously observed in D. discoideum and low levels of genetic variation observed in wild D. discoideum populations. In addition, D. discoideum has been shown to be quite resistant to DNA damage, which suggests an efficient DNA-repair mechanism that could be an adaptation to life in soil and frequent exposure to intracellular and extracellular mutagenic compounds. The social aspect of the life cycle of D. discoideum and a large portion of the genome under relaxed selection during vegetative growth could also select for a low mutation rate. This hypothesis is supported by a significantly lower mutation rate per cell division in multicellular eukaryotes compared with unicellular eukaryotes.

  2. Down-regulation of Cell Surface Cyclic AMP Receptors and Desensitization of Cyclic AMP-stimulated Adenylate Cyclase by Cyclic AMP in Dictyostelium discoideum. Kinetics and Concentration Dependence

    NARCIS (Netherlands)

    Haastert, Peter J.M. van

    1987-01-01

    cAMP binds to Dictyostelium discoideum surface receptors and induces a transient activation of adenylate cyclase, which is followed by desensitization. cAMP also induces a loss of detectable surface receptors (down-regulation). Cells were incubated with constant cAMP concentrations, washed free of

  3. Effect of sodium fluoride on the amount of polyribosomes, single ribosomes and ribosomal subunits in a cellular slime mold, Dictyostelium discoideum

    Energy Technology Data Exchange (ETDEWEB)

    Sameshima, M; Ito, K; Iwabuchi, M

    1972-01-01

    In the slime mold, Dictyostelium discoideum, when the rate of protein synthesis was decreased by NaF, free 80-S ribosomes accumulated at the expense of polyribosomes, while 60-S and 40-S ribosomal subunits remained almost constant. The same level of ribosomal subunits was also maintained in cells after incubation with cycloheximide or at the stationary phase of growth.

  4. Specificity of the Cyclic GMP-Binding Activity and of a Cyclic GMP-Dependent Cyclic GMP Phosphodiesterase in Dictyostelium discoideum

    NARCIS (Netherlands)

    Haastert, Peter J.M. van; Walsum, Hans van; Meer, Rob C. van der; Bulgakov, Roman; Konijn, Theo M.

    1982-01-01

    The nucleotide specificity of the cyclic GMP-binding activity in a homogenate of Dictyostelium discoideum was determined by competition of cyclic GMP derivatives with [8-3H] cyclic GMP for the binding sites. The results indicate that cyclic GMP is bound to the binding proteins by hydrogen bonds at

  5. Structural and functional studies of a family of Dictyostelium discoideum developmentally regulated, prestalk genes coding for small proteins

    Directory of Open Access Journals (Sweden)

    Escalante Ricardo

    2008-01-01

    Full Text Available Abstract Background The social amoeba Dictyostelium discoideum executes a multicellular development program upon starvation. This morphogenetic process requires the differential regulation of a large number of genes and is coordinated by extracellular signals. The MADS-box transcription factor SrfA is required for several stages of development, including slug migration and spore terminal differentiation. Results Subtractive hybridization allowed the isolation of a gene, sigN (SrfA-induced gene N, that was dependent on the transcription factor SrfA for expression at the slug stage of development. Homology searches detected the existence of a large family of sigN-related genes in the Dictyostelium discoideum genome. The 13 most similar genes are grouped in two regions of chromosome 2 and have been named Group1 and Group2 sigN genes. The putative encoded proteins are 87–89 amino acids long. All these genes have a similar structure, composed of a first exon containing a 13 nucleotides long open reading frame and a second exon comprising the remaining of the putative coding region. The expression of these genes is induced at10 hours of development. Analyses of their promoter regions indicate that these genes are expressed in the prestalk region of developing structures. The addition of antibodies raised against SigN Group 2 proteins induced disintegration of multi-cellular structures at the mound stage of development. Conclusion A large family of genes coding for small proteins has been identified in D. discoideum. Two groups of very similar genes from this family have been shown to be specifically expressed in prestalk cells during development. Functional studies using antibodies raised against Group 2 SigN proteins indicate that these genes could play a role during multicellular development.

  6. An Autocrine Proliferation Repressor Regulates Dictyostelium discoideum Proliferation and Chemorepulsion Using the G Protein-Coupled Receptor GrlH

    Directory of Open Access Journals (Sweden)

    Yu Tang

    2018-02-01

    Full Text Available In eukaryotic microbes, little is known about signals that inhibit the proliferation of the cells that secrete the signal, and little is known about signals (chemorepellents that cause cells to move away from the source of the signal. Autocrine proliferation repressor protein A (AprA is a protein secreted by the eukaryotic microbe Dictyostelium discoideum. AprA is a chemorepellent for and inhibits the proliferation of D. discoideum. We previously found that cells sense AprA using G proteins, suggesting the existence of a G protein-coupled AprA receptor. To identify the AprA receptor, we screened mutants lacking putative G protein-coupled receptors. We found that, compared to the wild-type strain, cells lacking putative receptor GrlH (grlH{macron} cells show rapid proliferation, do not have large numbers of cells moving away from the edges of colonies, are insensitive to AprA-induced proliferation inhibition and chemorepulsion, and have decreased AprA binding. Expression of GrlH in grlH{macron} cells (grlH{macron}/grlHOE rescues the phenotypes described above. These data indicate that AprA signaling may be mediated by GrlH in D. discoideum.

  7. The actinome of Dictyostelium discoideum in comparison to actins and actin-related proteins from other organisms.

    Directory of Open Access Journals (Sweden)

    Jayabalan M Joseph

    Full Text Available Actin belongs to the most abundant proteins in eukaryotic cells which harbor usually many conventional actin isoforms as well as actin-related proteins (Arps. To get an overview over the sometimes confusing multitude of actins and Arps, we analyzed the Dictyostelium discoideum actinome in detail and compared it with the genomes from other model organisms. The D. discoideum actinome comprises 41 actins and actin-related proteins. The genome contains 17 actin genes which most likely arose from consecutive gene duplications, are all active, in some cases developmentally regulated and coding for identical proteins (Act8-group. According to published data, the actin fraction in a D. discoideum cell consists of more than 95% of these Act8-type proteins. The other 16 actin isoforms contain a conventional actin motif profile as well but differ in their protein sequences. Seven actin genes are potential pseudogenes. A homology search of the human genome using the most typical D. discoideum actin (Act8 as query sequence finds the major actin isoforms such as cytoplasmic beta-actin as best hit. This suggests that the Act8-group represents a nearly perfect actin throughout evolution. Interestingly, limited data from D. fasciculatum, a more ancient member among the social amoebae, show different relationships between conventional actins. The Act8-type isoform is most conserved throughout evolution. Modeling of the putative structures suggests that the majority of the actin-related proteins is functionally unrelated to canonical actin. The data suggest that the other actin variants are not necessary for the cytoskeleton itself but rather regulators of its dynamical features or subunits in larger protein complexes.

  8. Partial genetic suppression of a loss-of-function mutant of the neuronal ceroid lipofuscinosis-associated protease TPP1 in Dictyostelium discoideum

    Directory of Open Access Journals (Sweden)

    Jonathan E. Phillips

    2015-02-01

    Full Text Available Neuronal ceroid lipofuscinosis (NCL is the most common childhood-onset neurodegenerative disease. NCL is inevitably fatal, and there is currently no treatment available. Children with NCL show a progressive decline in movement, vision and mental abilities, and an accumulation of autofluorescent deposits in neurons and other cell types. Late-infantile NCL is caused by mutations in the lysosomal protease tripeptidyl peptidase 1 (TPP1. TPP1 cleaves tripeptides from the N-terminus of proteins in vitro, but little is known about the physiological function of TPP1. TPP1 shows wide conservation in vertebrates but it is not found in Drosophila, Caenorhabditis elegans or Saccharomyces cerevisiae. Here, we characterize ddTpp1, a TPP1 ortholog present in the social amoeba Dictyostelium discoideum. Lysates from cells lacking ddTpp1 show a reduced but not abolished ability to cleave a TPP1 substrate, suggesting that other Dictyostelium enzymes can perform this cleavage. ddTpp1 and human TPP1 localize to the lysosome in Dictyostelium, indicating conserved function and trafficking. Cells that lack ddTpp1 show precocious multicellular development and a reduced ability to form spores during development. When cultured in autophagy-stimulating conditions, cells lacking ddTpp1 rapidly decrease in size and are less viable than wild-type cells, suggesting that one function of ddTpp1 could be to limit autophagy. Cells that lack ddTpp1 exhibit strongly impaired development in the presence of the lysosome-perturbing drug chloroquine, and this phenotype can be suppressed through a secondary mutation in the gene that we name suppressor of tpp1− A (stpA, which encodes a protein with some similarity to mammalian oxysterol-binding proteins (OSBPs. Taken together, these results suggest that targeting specific proteins could be a viable way to suppress the effects of loss of TPP1 function.

  9. Fluorographic detection of tritiated glycopeptides and oligosaccharides separated on polyacrylamide gels: analysis of glycans from Dictyostelium discoideum glycoproteins

    International Nuclear Information System (INIS)

    Prem Das, O.; Henderson, E.J.

    1986-01-01

    Previous workers have shown that oligosaccharides and glycopeptides can be separated by electrophoresis in buffers containing borate ions. However, normal fluorography of tritium-labeled structures cannot be performed because the glycans are soluble and can diffuse during equilibration with scintillants. This problem has been circumvented by equilibration of the gel with 2,5-diphenyloxazole (PPO) prior to electrophoresis. The presence of PPO in the gel during electrophoresis does not alter mobility of the glycopeptides and oligosaccharides. After electrophoresis, the gel is simply dried and fluorography performed. This allows sensitive and precise comparisons of labeled samples in parallel lanes of a slab gel and, since mobilities are highly reproducible, between different gels. The procedure is preparative in that after fluorography the gel bands can be quantitatively eluted for further study, without any apparent modification by the procedure. In this report, the procedure is illustrated by fractionation of both neutral and anionic glycopeptides produced by the cellular slime mold Dictyostelium discoideum

  10. The TOM Complex of Amoebozoans: the Cases of the Amoeba Acanthamoeba castellanii and the Slime Mold Dictyostelium discoideum.

    Science.gov (United States)

    Wojtkowska, Małgorzata; Buczek, Dorota; Stobienia, Olgierd; Karachitos, Andonis; Antoniewicz, Monika; Slocinska, Małgorzata; Makałowski, Wojciech; Kmita, Hanna

    2015-07-01

    Protein import into mitochondria requires a wide variety of proteins, forming complexes in both mitochondrial membranes. The TOM complex (translocase of the outer membrane) is responsible for decoding of targeting signals, translocation of imported proteins across or into the outer membrane, and their subsequent sorting. Thus the TOM complex is regarded as the main gate into mitochondria for imported proteins. Available data indicate that mitochondria of representative organisms from across the major phylogenetic lineages of eukaryotes differ in subunit organization of the TOM complex. The subunit organization of the TOM complex in the Amoebozoa is still elusive, so we decided to investigate its organization in the soil amoeba Acanthamoeba castellanii and the slime mold Dictyostelium discoideum. They represent two major subclades of the Amoebozoa: the Lobosa and Conosa, respectively. Our results confirm the presence of Tom70, Tom40 and Tom7 in the A. castellanii and D. discoideum TOM complex, while the presence of Tom22 and Tom20 is less supported. Interestingly, the Tom proteins display the highest similarity to Opisthokonta cognate proteins, with the exception of Tom40. Thus representatives of two major subclades of the Amoebozoa appear to be similar in organization of the TOM complex, despite differences in their lifestyle. Copyright © 2015 The Authors. Published by Elsevier GmbH.. All rights reserved.

  11. Clues to γ-secretase, huntingtin and Hirano body normal function using the model organism Dictyostelium discoideum

    Directory of Open Access Journals (Sweden)

    Myre Michael A

    2012-04-01

    Full Text Available Abstract Many neurodegenerative disorders, although related by their destruction of brain function, display remarkable cellular and/or regional pathogenic specificity likely due to a deregulated functionality of the mutant protein. However, neurodegenerative disease genes, for example huntingtin (HTT, the ataxins, the presenilins (PSEN1/PSEN2 are not simply localized to neurons but are ubiquitously expressed throughout peripheral tissues; it is therefore paramount to properly understand the earliest precipitating events leading to neuronal pathogenesis to develop effective long-term therapies. This means, in no unequivocal terms, it is crucial to understand the gene's normal function. Unfortunately, many genes are often essential for embryogenesis which precludes their study in whole organisms. This is true for HTT, the β-amyloid precursor protein (APP and presenilins, responsible for early onset Alzheimer's disease (AD. To better understand neurological disease in humans, many lower and higher eukaryotic models have been established. So the question arises: how reasonable is the use of organisms to study neurological disorders when the model of choice does not contain neurons? Here we will review the surprising, and novel emerging use of the model organism Dictyostelium discoideum, a species of soil-living amoeba, as a valuable biomedical tool to study the normal function of neurodegenerative genes. Historically, the evidence on the usefulness of simple organisms to understand the etiology of cellular pathology cannot be denied. But using an organism without a central nervous system to understand diseases of the brain? We will first introduce the life cycle of Dictyostelium, the presence of many disease genes in the genome and how it has provided unique opportunities to identify mechanisms of disease involving actin pathologies, mitochondrial disease, human lysosomal and trafficking disorders and host-pathogen interactions. Secondly, I will

  12. dictyExpress: a Dictyostelium discoideum gene expression database with an explorative data analysis web-based interface

    Science.gov (United States)

    Rot, Gregor; Parikh, Anup; Curk, Tomaz; Kuspa, Adam; Shaulsky, Gad; Zupan, Blaz

    2009-01-01

    Background Bioinformatics often leverages on recent advancements in computer science to support biologists in their scientific discovery process. Such efforts include the development of easy-to-use web interfaces to biomedical databases. Recent advancements in interactive web technologies require us to rethink the standard submit-and-wait paradigm, and craft bioinformatics web applications that share analytical and interactive power with their desktop relatives, while retaining simplicity and availability. Results We have developed dictyExpress, a web application that features a graphical, highly interactive explorative interface to our database that consists of more than 1000 Dictyostelium discoideum gene expression experiments. In dictyExpress, the user can select experiments and genes, perform gene clustering, view gene expression profiles across time, view gene co-expression networks, perform analyses of Gene Ontology term enrichment, and simultaneously display expression profiles for a selected gene in various experiments. Most importantly, these tasks are achieved through web applications whose components are seamlessly interlinked and immediately respond to events triggered by the user, thus providing a powerful explorative data analysis environment. Conclusion dictyExpress is a precursor for a new generation of web-based bioinformatics applications with simple but powerful interactive interfaces that resemble that of the modern desktop. While dictyExpress serves mainly the Dictyostelium research community, it is relatively easy to adapt it to other datasets. We propose that the design ideas behind dictyExpress will influence the development of similar applications for other model organisms. PMID:19706156

  13. An Autocrine Proliferation Repressor Regulates Dictyostelium discoideum Proliferation and Chemorepulsion Using the G Protein-Coupled Receptor GrlH.

    Science.gov (United States)

    Tang, Yu; Wu, Yuantai; Herlihy, Sarah E; Brito-Aleman, Francisco J; Ting, Jose H; Janetopoulos, Chris; Gomer, Richard H

    2018-02-13

    In eukaryotic microbes, little is known about signals that inhibit the proliferation of the cells that secrete the signal, and little is known about signals (chemorepellents) that cause cells to move away from the source of the signal. Autocrine proliferation repressor protein A (AprA) is a protein secreted by the eukaryotic microbe Dictyostelium discoideum AprA is a chemorepellent for and inhibits the proliferation of D. discoideum We previously found that cells sense AprA using G proteins, suggesting the existence of a G protein-coupled AprA receptor. To identify the AprA receptor, we screened mutants lacking putative G protein-coupled receptors. We found that, compared to the wild-type strain, cells lacking putative receptor GrlH ( grlH¯ cells) show rapid proliferation, do not have large numbers of cells moving away from the edges of colonies, are insensitive to AprA-induced proliferation inhibition and chemorepulsion, and have decreased AprA binding. Expression of GrlH in grlH¯ cells ( grlH¯/grlH OE ) rescues the phenotypes described above. These data indicate that AprA signaling may be mediated by GrlH in D. discoideum IMPORTANCE Little is known about how eukaryotic cells can count themselves and thus regulate the size of a tissue or density of cells. In addition, little is known about how eukaryotic cells can sense a repellant signal and move away from the source of the repellant, for instance, to organize the movement of cells in a developing embryo or to move immune cells out of a tissue. In this study, we found that a eukaryotic microbe uses G protein-coupled receptors to mediate both cell density sensing and chemorepulsion. Copyright © 2018 Tang et al.

  14. 1H, 15N and 13C assignments of domain 5 of Dictyostelium discoideum gelation factor (ABP-120) in its native and 8M urea-denatured states.

    Science.gov (United States)

    Hsu, Shang-Te Danny; Cabrita, Lisa D; Christodoulou, John; Dobson, Christopher M

    2009-06-01

    The gelation factor from Dictyostelium discoideum (ABP-120) is an actin binding protein consisting of six immunoglobulin (Ig) domains in the C-terminal rod domain. We have recently used the pair of domains 5 and 6 of ABP-120 as a model system for studying multi-domain nascent chain folding on the ribosome. Here we present the NMR assignments of domain 5 in its native and 8M urea-denatured states.

  15. Loss of Cln3 Function in the Social Amoeba Dictyostelium discoideum Causes Pleiotropic Effects That Are Rescued by Human CLN3

    Science.gov (United States)

    Huber, Robert J.

    2014-01-01

    The neuronal ceroid lipofuscinoses (NCL) are a group of inherited, severe neurodegenerative disorders also known as Batten disease. Juvenile NCL (JNCL) is caused by recessive loss-of-function mutations in CLN3, which encodes a transmembrane protein that regulates endocytic pathway trafficking, though its primary function is not yet known. The social amoeba Dictyostelium discoideum is increasingly utilized for neurological disease research and is particularly suited for investigation of protein function in trafficking. Therefore, here we establish new overexpression and knockout Dictyostelium cell lines for JNCL research. Dictyostelium Cln3 fused to GFP localized to the contractile vacuole system and to compartments of the endocytic pathway. cln3− cells displayed increased rates of proliferation and an associated reduction in the extracellular levels and cleavage of the autocrine proliferation repressor, AprA. Mid- and late development of cln3− cells was precocious and cln3− slugs displayed increased migration. Expression of either Dictyostelium Cln3 or human CLN3 in cln3− cells suppressed the precocious development and aberrant slug migration, which were also suppressed by calcium chelation. Taken together, our results show that Cln3 is a pleiotropic protein that negatively regulates proliferation and development in Dictyostelium. This new model system, which allows for the study of Cln3 function in both single cells and a multicellular organism, together with the observation that expression of human CLN3 restores abnormalities in Dictyostelium cln3− cells, strongly supports the use of this new model for JNCL research. PMID:25330233

  16. Loss of Cln3 function in the social amoeba Dictyostelium discoideum causes pleiotropic effects that are rescued by human CLN3.

    Directory of Open Access Journals (Sweden)

    Robert J Huber

    Full Text Available The neuronal ceroid lipofuscinoses (NCL are a group of inherited, severe neurodegenerative disorders also known as Batten disease. Juvenile NCL (JNCL is caused by recessive loss-of-function mutations in CLN3, which encodes a transmembrane protein that regulates endocytic pathway trafficking, though its primary function is not yet known. The social amoeba Dictyostelium discoideum is increasingly utilized for neurological disease research and is particularly suited for investigation of protein function in trafficking. Therefore, here we establish new overexpression and knockout Dictyostelium cell lines for JNCL research. Dictyostelium Cln3 fused to GFP localized to the contractile vacuole system and to compartments of the endocytic pathway. cln3- cells displayed increased rates of proliferation and an associated reduction in the extracellular levels and cleavage of the autocrine proliferation repressor, AprA. Mid- and late development of cln3- cells was precocious and cln3- slugs displayed increased migration. Expression of either Dictyostelium Cln3 or human CLN3 in cln3- cells suppressed the precocious development and aberrant slug migration, which were also suppressed by calcium chelation. Taken together, our results show that Cln3 is a pleiotropic protein that negatively regulates proliferation and development in Dictyostelium. This new model system, which allows for the study of Cln3 function in both single cells and a multicellular organism, together with the observation that expression of human CLN3 restores abnormalities in Dictyostelium cln3- cells, strongly supports the use of this new model for JNCL research.

  17. Dictyostelium discoideum: mutants in the biosynthesis of the lipid-linked precursor of N-linked oligosaccharides

    International Nuclear Information System (INIS)

    Freeze, H.; Willies, L.; Hamilton, S.

    1986-01-01

    The lysosomal enzymes of Dictyostelium discoideum share highly immunogenic oligosaccharides which contain multiple Man-6-SO 4 residues. Two mutant strains which lack the shared antigenic determinant were analyzed in an attempt to identify the primary defect in each. [ 3 H]Man labelled N-linked oligosaccharides of secreted glycoproteins were released by Endo/PNGaseF digestion and analyzed. Both of the mutant strains produced smaller, less sulfated oligosaccharides compared to the wild-type, yet both still contained considerable amounts of Man-6-SO 4 . The size of the precursor lipid-linked oligosaccharide from the wild-type is consistent with a Glc 3 Man 9 GlcNAc 2 structure, while those from both of the mutants have an oligosaccharide the size of Man 5 GlcNAc 2 . The authors conclude that both of the mutants are defective in the biosynthesis of the precursor oligosaccharide. Both oligosaccharides from the mutants contain a tri-mannosyl core and are not glucosylated. Two of the five Man residues are released by a 1,2 specific α mannosidase. Based on the size and mannosidase digestions the authors conclude that 4/5 of the Man residues on the α1,6 branch of the β-linked Man residues are missing. Thus, these residues must be required to define the shared antigenic determinant

  18. Systematic Analysis of γ-Aminobutyric Acid (GABA) Metabolism and Function in the Social Amoeba Dictyostelium discoideum*

    Science.gov (United States)

    Wu, Yuantai; Janetopoulos, Chris

    2013-01-01

    While GABA has been suggested to regulate spore encapsulation in the social amoeba Dictyostelium discoideum, the metabolic profile and other potential functions of GABA during development remain unclear. In this study, we investigated the homeostasis of GABA metabolism by disrupting genes related to GABA metabolism and signaling. Extracellular levels of GABA are tightly regulated during early development, and GABA is generated by the glutamate decarboxylase, GadB, during growth and in early development. However, overexpression of the prespore-specific homologue, GadA, in the presence of GadB reduces production of extracellular GABA. Perturbation of extracellular GABA levels delays the process of aggregation. Cytosolic GABA is degraded by the GABA transaminase, GabT, in the mitochondria. Disruption of a putative vesicular GABA transporter (vGAT) homologue DdvGAT reduces secreted GABA. We identified the GABAB receptor-like family member GrlB as the major GABA receptor during early development, and either disruption or overexpression of GrlB delays aggregation. This delay is likely the result of an abolished pre-starvation response and late expression of several “early” developmental genes. Distinct genes are employed for GABA generation during sporulation. During sporulation, GadA alone is required for generating GABA and DdvGAT is likely responsible for GABA secretion. GrlE but not GrlB is the GABA receptor during late development. PMID:23548898

  19. Uncovering a role for the tail of the Dictyostelium discoideum SadA protein in cell-substrate adhesion.

    Science.gov (United States)

    Kowal, Anthony S; Chisholm, Rex L

    2011-05-01

    Previous work from our laboratory showed that the Dictyostelium discoideum SadA protein plays a central role in cell-substrate adhesion. SadA null cells exhibit a loss of adhesion, a disrupted actin cytoskeleton, and a cytokinesis defect. How SadA mediates these phenotypes is unknown. This work addresses the mechanism of SadA function, demonstrating an important role for the C-terminal cytoplasmic tail in SadA function. We found that a SadA tailless mutant was unable to rescue the sadA adhesion deficiency, and overexpression of the SadA tail domain reduced adhesion in wild-type cells. We also show that SadA is closely associated with the actin cytoskeleton. Mutagenesis studies suggested that four serine residues in the tail, S924/S925 and S940/S941, may regulate association of SadA with the actin cytoskeleton. Glutathione S-transferase pull-down assays identified at least one likely interaction partner of the SadA tail, cortexillin I, a known actin bundling protein. Thus, our data demonstrate an important role for the carboxy-terminal cytoplasmic tail in SadA function and strongly suggest that a phosphorylation event in this tail regulates an interaction with cortexillin I. Based on our data, we propose a model for the function of SadA.

  20. eIF2α Kinases Control Chalone Production in Dictyostelium discoideum

    Science.gov (United States)

    Bowman, Robert L.; Xiong, Yanhua; Kirsten, Janet H.; Singleton, Charles K.

    2011-01-01

    Growing Dictyostelium cells secrete CfaD and AprA, two proteins that have been characterized as chalones. They exist within a high-molecular-weight complex that reversibly inhibits cell proliferation, but not growth, via cell surface receptors and a signaling pathway that includes G proteins. How the production of these two proteins is regulated is unknown. Dictyostelium cells possess three GCN2-type eukaryotic initiation factor 2 α subunit (eIF2α) kinases, proteins that phosphorylate the translational initiation factor eIF2α and possess a tRNA binding domain involved in their regulation. The Dictyostelium kinases have been shown to function during development in regulating several processes. We show here that expression of an unregulated, activated kinase domain greatly inhibits cell proliferation. The inhibitory effect on proliferation is not due to a general inhibition of translation. Instead, it is due to enhanced production of a secreted factor(s). Indeed, extracellular CfaD and AprA proteins, but not their mRNAs, are overproduced in cells expressing the activated kinase domain. The inhibition of proliferation is not seen when the activated kinase domain is expressed in cells lacking CfaD or AprA or in cells that contain a nonphosphorylatable eIF2α. We conclude that production of the chalones CfaD and AprA is translationally regulated by eIF2α phosphorylation. Both proteins are upregulated at the culmination of development, and this enhanced production is lacking in a strain that possesses a nonphosphorylatable eIF2α. PMID:21278229

  1. Extracellular calmodulin regulates growth and cAMP-mediated chemotaxis in Dictyostelium discoideum

    International Nuclear Information System (INIS)

    O’Day, Danton H.; Huber, Robert J.; Suarez, Andres

    2012-01-01

    Highlights: ► Extracellular calmodulin is present throughout growth and development in Dictyostelium. ► Extracellular calmodulin localizes within the ECM during development. ► Extracellular calmodulin inhibits cell proliferation and increases chemotaxis. ► Extracellular calmodulin exists in eukaryotic microbes. ► Extracellular calmodulin may be functionally as important as intracellular calmodulin. -- Abstract: The existence of extracellular calmodulin (CaM) has had a long and controversial history. CaM is a ubiquitous calcium-binding protein that has been found in every eukaryotic cell system. Calcium-free apo-CaM and Ca 2+ /CaM exert their effects by binding to and regulating the activity of CaM-binding proteins (CaMBPs). Most of the research done to date on CaM and its CaMBPs has focused on their intracellular functions. The presence of extracellular CaM is well established in a number of plants where it functions in proliferation, cell wall regeneration, gene regulation and germination. While CaM has been detected extracellularly in several animal species, including frog, rat, rabbit and human, its extracellular localization and functions are less well established. In contrast the study of extracellular CaM in eukaryotic microbes remains to be done. Here we show that CaM is constitutively expressed and secreted throughout asexual development in Dictyostelium where the presence of extracellular CaM dose-dependently inhibits cell proliferation but increases cAMP mediated chemotaxis. During development, extracellular CaM localizes within the slime sheath where it coexists with at least one CaMBP, the matricellular CaM-binding protein CyrA. Coupled with previous research, this work provides direct evidence for the existence of extracellular CaM in the Dictyostelium and provides insight into its functions in this model amoebozoan.

  2. RNAi silenced Dd-grp94 (Dictyostelium discoideum glucose-regulated protein 94 kDa) cell lines in Dictyostelium exhibit marked reduction in growth rate and delay in development.

    Science.gov (United States)

    Baviskar, Sandhya N; Shields, Malcolm S

    2010-01-01

    Glucose-regulated 94 kDa protein (Grp94) is a resident of the endoplasmic reticulum (ER) of multicellular eukaryotes. It is a constitutively expressed protein that is overexpressed in certain abnormal conditions of the cell such as depletion of glucose and calcium, and low oxygen and pH. The protein is also implicated in diseased conditions like cancer and Alzheimer's disease. In this study, the consequences of downregulation of Grp94 were investigated at both unicellular and multicellular stages of Dictyostelium discoideum. Previous studies have shown the expression of Dd-Grp94 (Dictyostelium discoideum glucose-regulated 94 kDa protein) in wild-type cells varies during development, and overexpression of Dd-Grp94 leads to abnormal cell shape and inhibition of development (i.e., formation of fruiting bodies). Grp94 is a known calcium binding protein and an efficient calcium buffer. Therefore, in the present study we hypothesized that downregulation of Dd-Grp94 protein would affect Dictyostelium cell structure, growth, and development. We found that Dd-grp94 RNAi recombinants exhibited reduced growth rate, cell size, and a subtle change in cell motility compared to the parental cells. The recombinants also exhibited a delay in development and small fruiting bodies. These results establish that Dd-grp94 plays a crucial role in determining normal cell structure, growth and differentiation.

  3. Uncovering a Role for the Tail of the Dictyostelium discoideum SadA Protein in Cell-Substrate Adhesion ▿ †

    OpenAIRE

    Kowal, Anthony S.; Chisholm, Rex L.

    2011-01-01

    Previous work from our laboratory showed that the Dictyostelium discoideum SadA protein plays a central role in cell-substrate adhesion. SadA null cells exhibit a loss of adhesion, a disrupted actin cytoskeleton, and a cytokinesis defect. How SadA mediates these phenotypes is unknown. This work addresses the mechanism of SadA function, demonstrating an important role for the C-terminal cytoplasmic tail in SadA function. We found that a SadA tailless mutant was unable to rescue the sadA adhesi...

  4. The ROCO kinase QkgA is necessary for proliferation inhibition by autocrine signals in Dictyostelium discoideum.

    Science.gov (United States)

    Phillips, Jonathan E; Gomer, Richard H

    2010-10-01

    AprA and CfaD are secreted proteins that function as autocrine signals to inhibit cell proliferation in Dictyostelium discoideum. Cells lacking AprA or CfaD proliferate rapidly, and adding AprA or CfaD to cells slows proliferation. Cells lacking the ROCO kinase QkgA proliferate rapidly, with a doubling time 83% of that of the wild type, and overexpression of a QkgA-green fluorescent protein (GFP) fusion protein slows cell proliferation. We found that qkgA(-) cells accumulate normal levels of extracellular AprA and CfaD. Exogenous AprA or CfaD does not slow the proliferation of cells lacking qkgA, and expression of QkgA-GFP in qkgA(-) cells rescues this insensitivity. Like cells lacking AprA or CfaD, cells lacking QkgA tend to be multinucleate, accumulate nuclei rapidly, and show a mass and protein accumulation per nucleus like those of the wild type, suggesting that QkgA negatively regulates proliferation but not growth. Despite their rapid proliferation, cells lacking AprA, CfaD, or QkgA expand as a colony on bacteria less rapidly than the wild type. Unlike AprA and CfaD, QkgA does not affect spore viability following multicellular development. Together, these results indicate that QkgA is necessary for proliferation inhibition by AprA and CfaD, that QkgA mediates some but not all of the effects of AprA and CfaD, and that QkgA may function downstream of these proteins in a signal transduction pathway regulating proliferation.

  5. Lack of Ecological and Life History Context Can Create the Illusion of Social Interactions in Dictyostelium discoideum.

    Science.gov (United States)

    Martínez-García, Ricardo; Tarnita, Corina E

    2016-12-01

    Studies of social microbes often focus on one fitness component (reproductive success within the social complex), with little information about or attention to other stages of the life cycle or the ecological context. This can lead to paradoxical results. The life cycle of the social amoeba Dictyostelium discoideum includes a multicellular stage in which not necessarily clonal amoebae aggregate upon starvation to form a possibly chimeric (genetically heterogeneous) fruiting body made of dead stalk cells and spores. The lab-measured reproductive skew in the spores of chimeras indicates strong social antagonism that should result in low genotypic diversity, which is inconsistent with observations from nature. Two studies have suggested that this inconsistency stems from the one-dimensional assessment of fitness (spore production) and that the solution lies in tradeoffs between multiple life-history traits, e.g.: spore size versus viability; and spore-formation (via aggregation) versus staying vegetative (as non-aggregated cells). We develop an ecologically-grounded, socially-neutral model (i.e. no social interactions between genotypes) for the life cycle of social amoebae in which we theoretically explore multiple non-social life-history traits, tradeoffs and tradeoff-implementing mechanisms. We find that spore production comes at the expense of time to complete aggregation, and, depending on the experimental setup, spore size and viability. Furthermore, experimental results regarding apparent social interactions within chimeric mixes can be qualitatively recapitulated under this neutral hypothesis, without needing to invoke social interactions. This allows for simple potential resolutions to the previously paradoxical results. We conclude that the complexities of life histories, including social behavior and multicellularity, can only be understood in the appropriate multidimensional ecological context, when considering all stages of the life cycle.

  6. Structure, dynamics and folding of an immunoglobulin domain of the gelation factor (ABP-120) from Dictyostelium discoideum.

    Science.gov (United States)

    Hsu, Shang-Te Danny; Cabrita, Lisa D; Fucini, Paola; Dobson, Christopher M; Christodoulou, John

    2009-05-15

    We have carried out a detailed structural and dynamical characterisation of the isolated fifth repeat of the gelation factor (ABP-120) from Dictyostelium discoideum (ddFLN5) by NMR spectroscopy to provide a basis for studies of co-translational folding on the ribosome of this immunoglobulin-like domain. The isolated ddFLN5 can fold autonomously in solution into a structure that resembles very closely the crystal structure of the domain in a construct in which the adjacent sixth repeat (ddFLN6) is covalently linked to its C-terminus in tandem but deviates locally from a second crystal structure in which ddFLN5 is flanked by ddFLN4 and ddFLN6 at both N- and C-termini. Conformational fluctuations were observed via (15)N relaxation methods and are primarily localised in the interstrand loops that encompass the C-terminal hemisphere. These fluctuations are distinct in location from the region where line broadening is observed in ddFLN5 when attached to the ribosome as part of a nascent chain. This observation supports the conclusion that the broadening is associated with interactions with the ribosome surface [Hsu, S. T. D., Fucini, P., Cabrita, L. D., Launay, H., Dobson, C. M. & Christodoulou, J. (2007). Structure and dynamics of a ribosome-bound nascent chain by NMR spectroscopy. Proc. Natl. Acad. Sci. USA, 104, 16516-16521]. The unfolding of ddFLN5 induced by high concentrations of urea shows a low population of a folding intermediate, as inferred from an intensity-based analysis, a finding that differs from that of ddFLN5 as a ribosome-bound nascent chain. These results suggest that interesting differences in detail may exist between the structure of the domain in isolation and when linked to the ribosome and between protein folding in vitro and the folding of a nascent chain as it emerges from the ribosome.

  7. Quadruplexes in 'Dicty': crystal structure of a four-quartet G-quadruplex formed by G-rich motif found in the Dictyostelium discoideum genome.

    Science.gov (United States)

    Guédin, Aurore; Lin, Linda Yingqi; Armane, Samir; Lacroix, Laurent; Mergny, Jean-Louis; Thore, Stéphane; Yatsunyk, Liliya A

    2018-06-01

    Guanine-rich DNA has the potential to fold into non-canonical G-quadruplex (G4) structures. Analysis of the genome of the social amoeba Dictyostelium discoideum indicates a low number of sequences with G4-forming potential (249-1055). Therefore, D. discoideum is a perfect model organism to investigate the relationship between the presence of G4s and their biological functions. As a first step in this investigation, we crystallized the dGGGGGAGGGGTACAGGGGTACAGGGG sequence from the putative promoter region of two divergent genes in D. discoideum. According to the crystal structure, this sequence folds into a four-quartet intramolecular antiparallel G4 with two lateral and one diagonal loops. The G-quadruplex core is further stabilized by a G-C Watson-Crick base pair and a A-T-A triad and displays high thermal stability (Tm > 90°C at 100 mM KCl). Biophysical characterization of the native sequence and loop mutants suggests that the DNA adopts the same structure in solution and in crystalline form, and that loop interactions are important for the G4 stability but not for its folding. Four-tetrad G4 structures are sparse. Thus, our work advances understanding of the structural diversity of G-quadruplexes and yields coordinates for in silico drug screening programs and G4 predictive tools.

  8. The PsB glycoprotein complex is secreted as a preassembled precursor of the spore coat in Dictyostelium discoideum.

    Science.gov (United States)

    Watson, N; McGuire, V; Alexander, S

    1994-09-01

    The PsB glycoprotein in Dictyostelium discoideum is one of a diverse group of developmentally regulated, prespore-cell-specific proteins, that contain a common O-linked oligosaccharide. This post-translational modification is dependent on the wild-type modB allele. The PsB protein exists as part of a multiprotein complex of six different proteins, which have different post-translational modifications and are held together by both covalent and non-covalent interactions (Watson et al. (1993). J. Biol. Chem. 268, 22634-22641). In this study we have used microscopic and biochemical analyses to examine the cellular localization and function of the PsB complex during development. We found that the PsB complex first accumulates in prespore vesicles in slug cells and is secreted later during culmination and becomes localized to both the extracellular matrix of the apical spore mass of mature fruiting bodies and to the inner layer of the spore coat. The PsB associated with the spore coat is covalently bound by disulfide bridges. The PsB protein always exists in a multiprotein complex, but the composition of the PsB complex changes during secretion and spore maturation. Some of the PsB complex proteins have been identified as spore coat proteins. These data demonstrate that some of the proteins that form the spore coat exist as a preassembled precursor complex. The PsB complex is secreted in a developmentally regulated manner during the process of spore differentiation, at which time proteins of the complex, as well as additional spore coat proteins, become covalently associated in at least two forms of extracellular matrix: the interspore matrix and the spore coat. These and other studies show that proteins with modB dependent O-linked oligosaccharides are involved in a wide variety of processes underlying morphogenesis in this organism. These developmental processes are the direct result of cellular mechanisms regulating protein targeting, assembly and secretion, and the

  9. Immobilization of Deoxyadenosine Kinase from Dictyostelium discoideum (DddAK) and Its Application in the 5’-Phosphorylation of Arabinosyladenine and Arabinosyl-2-fluoroadenine

    DEFF Research Database (Denmark)

    Serra, Immacolata; Ubiali, Daniela; Piskur, Jure

    2017-01-01

    Deoxyadenosine kinase from Dictyostelium discoideum (DddAK) phosphorylates its natural substrate (2’‐deoxyadenosine, dAdo) as well as the arabinosyladenine analogues vidarabine (araA) and fludarabine (F‐araA) to their corresponding 5’‐monophosphates. DddAK has been here immobilized by ionic...... interaction on an aminated epoxy‐functionalized support (SepabeadsTM EC‐EP), and cross‐linked with oxidized dextran. The final activity recovery was 33–42 %, depending on the protein loading. Immobilization enhanced the stability of DddAK at pH 10 and, to a lesser extent, at 45 °C. Phosphorylation of d...

  10. Crystallization and preliminary X-ray crystallographic analysis of the NmrA-like DDB-G0286605 protein from the social amoeba Dictyostelium discoideum

    International Nuclear Information System (INIS)

    Kim, Min-Kyu; Yim, Hyung-Soon; Kang, Sa-Ouk

    2010-01-01

    In order to investigate its structure and function, the NmrA-like domain-containing DDB-G0286605 protein from D. discoideum was expressed, purified and crystallized. X-ray diffraction analysis is reported to a resolution of 1.64 Å. The DDB-G0286605 gene product from Dictyostelium discoideum, an NmrA-like protein that belongs to the short-chain dehydrogenase/reductase family, has been crystallized by the hanging-drop vapour-diffusion method at 295 K. A 1.64 Å resolution data set was collected using synchrotron radiation. The DDB-G0286605 protein crystals belonged to space group P2 1 , with unit-cell parameters a = 67.598, b = 54.935, c = 84.219 Å, β = 109.620°. Assuming the presence of two molecules in the asymmetric unit, the solvent content was estimated to be about 43.25% with 99% probability. Molecular-replacement trials were attempted with three NmrA-like proteins, NmrA, HSCARG and QOR2, as search models, but failed. This may be a consequence of the low sequence identity between the DDB-G0286605 protein and the search models (DDB-G0286605 has a primary-sequence identity of 28, 32 and 19% to NmrA, HCARG and QOR2, respectively)

  11. MicroRNAs in Amoebozoa: deep sequencing of the small RNA population in the social amoeba Dictyostelium discoideum reveals developmentally regulated microRNAs.

    Science.gov (United States)

    Avesson, Lotta; Reimegård, Johan; Wagner, E Gerhart H; Söderbom, Fredrik

    2012-10-01

    The RNA interference machinery has served as a guardian of eukaryotic genomes since the divergence from prokaryotes. Although the basic components have a shared origin, silencing pathways directed by small RNAs have evolved in diverse directions in different eukaryotic lineages. Micro (mi)RNAs regulate protein-coding genes and play vital roles in plants and animals, but less is known about their functions in other organisms. Here, we report, for the first time, deep sequencing of small RNAs from the social amoeba Dictyostelium discoideum. RNA from growing single-cell amoebae as well as from two multicellular developmental stages was sequenced. Computational analyses combined with experimental data reveal the expression of miRNAs, several of them exhibiting distinct expression patterns during development. To our knowledge, this is the first report of miRNAs in the Amoebozoa supergroup. We also show that overexpressed miRNA precursors generate miRNAs and, in most cases, miRNA* sequences, whose biogenesis is dependent on the Dicer-like protein DrnB, further supporting the presence of miRNAs in D. discoideum. In addition, we find miRNAs processed from hairpin structures originating from an intron as well as from a class of repetitive elements. We believe that these repetitive elements are sources for newly evolved miRNAs.

  12. Assets of the non-pathogenic microorganism Dictyostelium discoideum as a model for the study of eukaryotic extracellular vesicles [v1; ref status: indexed, http://f1000r.es/pa

    Directory of Open Access Journals (Sweden)

    Irène Tatischeff

    2013-03-01

    Full Text Available Dictyostelium discoideum microvesicles have recently been presented as a valuable model for eukaryotic extracellular vesicles. Here, the advantages of D. discoideum for unraveling important biological functions of extracellular vesicles in general are detailed. D. discoideum, a non-pathogenic eukaryotic microorganism, belongs to a billion-year-old Amoeboza lineage, which diverged from the animal-fungal lineage after the plant animal-split. During growth and early starvation-induced development, it presents analogies with lymphocytes and macrophages with regard to motility and phagocytosis capability, respectively. Its 6-chromosome genome codes for about 12,500 genes, some showing analogies with human genes. The presence of extracellular vesicles during cell growth has been evidenced as a detoxification mechanism of various structurally unrelated drugs. Controls led to the discovery of constitutive extracellular vesicle secretion in this microorganism, which was an important point. It means that the secretion of extracellular vesicles occurs, in the absence of any drug, during both cell growth and early development. This constitutive secretion of D. discoideum cells is very likely to play a role in intercellular communication. The detoxifying secreted vesicles, which can transport drugs outside the cells, can also act as "Trojan horses", capable of transferring these drugs not only into naïve D. discoideum cells, but into human cells as well. Therefore, these extracellular vesicles were proposed as a new biological drug delivery tool. Moreover, Dictyostelium, chosen by the NIH (USA as a new model organism for biomedical research, has already been used for studying some human diseases. These cells, which are much easier to manipulate than human cells, can be easily designed in simple conditioned medium experiments. Owing to the increasing consensus that extracellular vesicles are probably important mediators of intercellular communication, D. discoideum

  13. Effect of drugs on lipid methylation, receptor-adenylate cyclase coupling and cyclic AMP secretion in Dictyostelium discoideum

    NARCIS (Netherlands)

    Van Waarde, Aren; Van Haastert, P.J.M.

    1986-01-01

    Intercellular communication in Dictyostelium discoldeum takes place by means of cyclic AMP-induced cyclic AMP-synthesis and secretion. Since phospholipid methylation has been suggested to play a role in receptor-adenylate cyclase coupling, we examined the effects of transmethylation inhibitors on

  14. Uncovering a Role for the Tail of the Dictyostelium discoideum SadA Protein in Cell-Substrate Adhesion ▿ †

    Science.gov (United States)

    Kowal, Anthony S.; Chisholm, Rex L.

    2011-01-01

    Previous work from our laboratory showed that the Dictyostelium discoideum SadA protein plays a central role in cell-substrate adhesion. SadA null cells exhibit a loss of adhesion, a disrupted actin cytoskeleton, and a cytokinesis defect. How SadA mediates these phenotypes is unknown. This work addresses the mechanism of SadA function, demonstrating an important role for the C-terminal cytoplasmic tail in SadA function. We found that a SadA tailless mutant was unable to rescue the sadA adhesion deficiency, and overexpression of the SadA tail domain reduced adhesion in wild-type cells. We also show that SadA is closely associated with the actin cytoskeleton. Mutagenesis studies suggested that four serine residues in the tail, S924/S925 and S940/S941, may regulate association of SadA with the actin cytoskeleton. Glutathione S-transferase pull-down assays identified at least one likely interaction partner of the SadA tail, cortexillin I, a known actin bundling protein. Thus, our data demonstrate an important role for the carboxy-terminal cytoplasmic tail in SadA function and strongly suggest that a phosphorylation event in this tail regulates an interaction with cortexillin I. Based on our data, we propose a model for the function of SadA. PMID:21441344

  15. The p21-activated kinase (PAK family member PakD is required for chemorepulsion and proliferation inhibition by autocrine signals in Dictyostelium discoideum.

    Directory of Open Access Journals (Sweden)

    Jonathan E Phillips

    Full Text Available In Dictyostelium discoideum, the secreted proteins AprA and CfaD function as reporters of cell density and regulate cell number by inhibiting proliferation at high cell densities. AprA also functions to disperse groups of cells at high density by acting as a chemorepellent. However, the signal transduction pathways associated with AprA and CfaD are not clear, and little is known about how AprA affects the cytoskeleton to regulate cell movement. We found that the p21-activated kinase (PAK family member PakD is required for both the proliferation-inhibiting activity of AprA and CfaD and the chemorepellent activity of AprA. Similar to cells lacking AprA or CfaD, cells lacking PakD proliferate to a higher cell density than wild-type cells. Recombinant AprA and CfaD inhibit the proliferation of wild-type cells but not cells lacking PakD. Like AprA and CfaD, PakD affects proliferation but does not significantly affect growth (the accumulation of mass on a per-nucleus basis. In contrast to wild-type cells, cells lacking PakD are not repelled from a source of AprA, and colonies of cells lacking PakD expand at a slower rate than wild-type cells, indicating that PakD is required for AprA-mediated chemorepulsion. A PakD-GFP fusion protein localizes to an intracellular punctum that is not the nucleus or centrosome, and PakD-GFP is also occasionally observed at the rear cortex of moving cells. Vegetative cells lacking PakD show excessive actin-based filopodia-like structures, suggesting that PakD affects actin dynamics, consistent with previously characterized roles of PAK proteins in actin regulation. Together, our results implicate PakD in AprA/CfaD signaling and show that a PAK protein is required for proper chemorepulsive cell movement in Dictyostelium.

  16. The p21-activated kinase (PAK) family member PakD is required for chemorepulsion and proliferation inhibition by autocrine signals in Dictyostelium discoideum.

    Science.gov (United States)

    Phillips, Jonathan E; Gomer, Richard H

    2014-01-01

    In Dictyostelium discoideum, the secreted proteins AprA and CfaD function as reporters of cell density and regulate cell number by inhibiting proliferation at high cell densities. AprA also functions to disperse groups of cells at high density by acting as a chemorepellent. However, the signal transduction pathways associated with AprA and CfaD are not clear, and little is known about how AprA affects the cytoskeleton to regulate cell movement. We found that the p21-activated kinase (PAK) family member PakD is required for both the proliferation-inhibiting activity of AprA and CfaD and the chemorepellent activity of AprA. Similar to cells lacking AprA or CfaD, cells lacking PakD proliferate to a higher cell density than wild-type cells. Recombinant AprA and CfaD inhibit the proliferation of wild-type cells but not cells lacking PakD. Like AprA and CfaD, PakD affects proliferation but does not significantly affect growth (the accumulation of mass) on a per-nucleus basis. In contrast to wild-type cells, cells lacking PakD are not repelled from a source of AprA, and colonies of cells lacking PakD expand at a slower rate than wild-type cells, indicating that PakD is required for AprA-mediated chemorepulsion. A PakD-GFP fusion protein localizes to an intracellular punctum that is not the nucleus or centrosome, and PakD-GFP is also occasionally observed at the rear cortex of moving cells. Vegetative cells lacking PakD show excessive actin-based filopodia-like structures, suggesting that PakD affects actin dynamics, consistent with previously characterized roles of PAK proteins in actin regulation. Together, our results implicate PakD in AprA/CfaD signaling and show that a PAK protein is required for proper chemorepulsive cell movement in Dictyostelium.

  17. Properties of a non-bioactive fluorescent derivative of differentiation-inducing factor-3, an anti-tumor agent found in Dictyostelium discoideum

    Directory of Open Access Journals (Sweden)

    Yuzuru Kubohara

    2014-03-01

    Full Text Available Differentiation-inducing factor-3 (DIF-3, found in the cellular slime mold Dictyostelium discoideum, and its derivatives, such as butoxy-DIF-3 (Bu-DIF-3, are potent anti-tumor agents. To investigate the activity of DIF-like molecules in tumor cells, we recently synthesized a green fluorescent DIF-3 derivative, BODIPY-DIF-3G, and analyzed its bioactivity and cellular localization. In this study, we synthesized a red (orange fluorescent DIF-3 derivative, BODIPY-DIF-3R, and compared the cellular localization and bioactivities of the two BODIPY-DIF-3s in HeLa human cervical cancer cells. Both fluorescent compounds penetrated the extracellular membrane within 0.5 h and localized mainly to the mitochondria. In formalin-fixed cells, the two BODIPY-DIF-3s also localized to the mitochondria, indicating that the BODIPY-DIF-3s were incorporated into mitochondria independently of the mitochondrial membrane potential. After treatment for 3 days, BODIPY-DIF-3G, but not BODIPY-DIF-3R, induced mitochondrial swelling and suppressed cell proliferation. Interestingly, the swollen mitochondria were stainable with BODIPY-DIF-3G but not with BODIPY-DIF-3R. When added to isolated mitochondria in vitro, BODIPY-DIF-3G increased dose-dependently the rate of O2 consumption, but BODIPY-DIF-3R did not. These results suggest that the bioactive BODIPY-DIF-3G suppresses cell proliferation, at least in part, by altering mitochondrial activity, whereas the non-bioactive BODIPY-DIF-3R localizes to the mitochondria but does not affect mitochondrial activity or cell proliferation.

  18. Mitochondria are the target organelle of differentiation-inducing factor-3, an anti-tumor agent isolated from Dictyostelium discoideum [corrected].

    Directory of Open Access Journals (Sweden)

    Yuzuru Kubohara

    Full Text Available Differentiation-inducing factor-3 (DIF-3, found in the cellular slime mold Dictyostelium discoideum, and its derivatives such as butoxy-DIF-3 (Bu-DIF-3 are potent anti-tumor agents. However, the precise mechanisms underlying the actions of DIF-3 remain to be elucidated. In this study, we synthesized a green fluorescent derivative of DIF-3, BODIPY-DIF-3, and a control fluorescent compound, Bu-BODIPY (butyl-BODIPY, and investigated how DIF-like molecules behave in human cervical cancer HeLa cells by using both fluorescence and electron microscopy. BODIPY-DIF-3 at 5-20 µ M suppressed cell growth in a dose-dependent manner, whereas Bu-BODIPY had minimal effect on cell growth. When cells were incubated with BODIPY-DIF-3 at 20 µM, it penetrated cell membranes within 0.5 h and localized mainly in mitochondria, while Bu-BODIPY did not stain the cells. Exposure of cells for 1-3 days to DIF-3, Bu-DIF-3, BODIPY-DIF-3, or CCCP (a mitochondrial uncoupler induced substantial mitochondrial swelling, suppressing cell growth. When added to isolated mitochondria, DIF-3, Bu-DIF-3, and BOIDPY-DIF-3, like CCCP, dose-dependently promoted the rate of oxygen consumption, but Bu-BODIPY did not. Our results suggest that these bioactive DIF-like molecules suppress cell growth, at least in part, by disturbing mitochondrial activity. This is the first report showing the cellular localization and behavior of DIF-like molecules in mammalian tumor cells.

  19. G-protein-mediated interconversions of cell-surface cAMP receptors and their involvement in excitation and desensitization of guanylate cyclase in Dictyostelium discoideum

    International Nuclear Information System (INIS)

    van Haastert, P.J.; de Wit, R.J.; Janssens, P.M.; Kesbeke, F.; DeGoede, J.

    1986-01-01

    In Dictyostelium discoideum cells, extracellular cAMP induces the rapid (within 2 s) activation of guanylate cyclase, which is followed by complete desensitization after about 10 s. cAMP binding to these cells is heterogeneous, showing a subclass of fast dissociating sites coupled to adenylate cyclase (A-sites) and a subclass of slowly dissociating sites coupled to guanylate cyclase (B-sites). The kinetics of the B-sites were further investigated on a seconds time scale. Statistical analysis of the association of [ 3 H]cAMP to the B-sites and dissociation of the complex revealed that the receptor can exist in three states which interconvert according to the following scheme. cAMP binds to the BF-state (off-rate 2.5 s) which rapidly (t1/2 = 3 s) converts to the BS-state (off-rate 15 s) and subsequently (without a detectable delay) into the BSS-state (off-rate 150 s). In membranes, both the BS- and BSS-states are converted to the BF-state by GTP and GDP, suggesting the involvement of a G-protein. Densensitized cells show a 80% reduction of the formation of the BSS-state, but no reduction of the BF- or BS-state. These data are combined into a model in which the transitions of the B-sites are mediated by a G-protein; activation of the G-protein and guanylate cyclase is associated with the transition of the BS- to the BSS-state of the receptor, whereas desensitization is associated with the inhibition of this transition

  20. TgrC1 mediates cell-cell adhesion by interacting with TgrB1 via mutual IPT/TIG domains during development of Dictyostelium discoideum.

    Science.gov (United States)

    Chen, Gong; Wang, Jun; Xu, Xiaoqun; Wu, Xiangfu; Piao, Ruihan; Siu, Chi-Hung

    2013-06-01

    Cell-cell adhesion plays crucial roles in cell differentiation and morphogenesis during development of Dictyostelium discoideum. The heterophilic adhesion protein TgrC1 (Tgr is transmembrane, IPT, IG, E-set, repeat protein) is expressed during cell aggregation, and disruption of the tgrC1 gene results in the arrest of development at the loose aggregate stage. We have used far-Western blotting coupled with MS to identify TgrB1 as the heterophilic binding partner of TgrC1. Co-immunoprecipitation and pull-down studies showed that TgrB1 and TgrC1 are capable of binding with each other in solution. TgrB1 and TgrC1 are encoded by a pair of adjacent genes which share a common promoter. Both TgrB1 and TgrC1 are type I transmembrane proteins, which contain three extracellular IPT/TIG (immunoglobulin, plexin, transcription factor-like/transcription factor immunoglobulin) domains. Antibodies raised against TgrB1 inhibit cell reassociation at the post-aggregation stage of development and block fruiting body formation. Ectopic expression of TgrB1 and TgrC1 driven by the actin15 promoter leads to heterotypic cell aggregation of vegetative cells. Using recombinant proteins that cover different portions of TgrB1 and TgrC1 in binding assays, we have mapped the cell-binding regions in these two proteins to Lys(537)-Ala(783) in TgrB1 and Ile(336)-Val(360) in TgrC1, corresponding to their respective TIG3 and TIG2 domain.

  1. The cellulose-binding activity of the PsB multiprotein complex is required for proper assembly of the spore coat and spore viability in Dictyostelium discoideum.

    Science.gov (United States)

    Srinivasan, S; Griffiths, K R; McGuire, V; Champion, A; Williams, K L; Alexander, S

    2000-08-01

    The terminal event of spore differentiation in the cellular slime mould Dictyostelium discoideum is the assembly of the spore coat, which surrounds the dormant amoeba and allows the organism to survive during extended periods of environmental stress. The spore coat is a polarized extracellular matrix composed of glycoproteins and cellulose. The process of spore coat formation begins by the regulated secretion of spore coat proteins from the prespore vesicles (PSVs). Four of the major spore coat proteins (SP96, PsB/SP85, SP70 and SP60) exist as a preassembled multiprotein complex within the PSVs. This complete complex has an endogenous cellulose-binding activity. Mutant strains lacking either the SP96 or SP70 proteins produce partial complexes that do not have cellulose-binding activity, while mutants lacking SP60 produce a partial complex that retains this activity. Using a combination of immunofluorescence microscopy and biochemical methods we now show that the lack of cellulose-binding activity in the SP96 and SP70 mutants results in abnormally assembled spore coats and spores with greatly reduced viability. In contrast, the SP60 mutant, in which the PsB complex retains its cellulose-binding activity, produces spores with apparently unaltered structure and viability. Thus, it is the loss of the cellulose-binding activity of the PsB complex, rather than the mere loss of individual spore coat proteins, that results in compromised spore coat structure. These results support the idea that the cellulose-binding activity associated with the complete PsB complex plays an active role in the assembly of the spore coat.

  2. PsB multiprotein complex of Dictyostelium discoideum. Demonstration of cellulose binding activity and order of protein subunit assembly.

    Science.gov (United States)

    McGuire, V; Alexander, S

    1996-06-14

    The differentiated spores of Dictyostelium are surrounded by an extracellular matrix, the spore coat, which protects them from environmental factors allowing them to remain viable for extended periods of time. This presumably is a major evolutionary advantage. This unique extracellular matrix is composed of cellulose and glycoproteins. Previous work has shown that some of these spore coat glycoproteins exist as a preassembled multiprotein complex (the PsB multiprotein complex) which is stored in the prespore vesicles (Watson, N., McGuire, V., and Alexander, S (1994) J. Cell Sci. 107, 2567-2579). Later in development, the complex is synchronously secreted from the prespore vesicles and incorporated into the spore coat. We now have shown that the PsB complex has a specific in vitro cellulose binding activity. The analysis of mutants lacking individual subunits of the PsB complex revealed the relative order of assembly of the subunit proteins and demonstrated that the protein subunits must be assembled for cellulose binding activity. These results provide a biochemical explanation for the localization of this multiprotein complex in the spore coat.

  3. Role of phospholipase C in Dictyostelium : Formation of inositol 1,4,5-trisphosphate and normal development in cells lacking phospholipase C activity

    NARCIS (Netherlands)

    Drayer, A. Lyndsay; Kaay, Jeroen van der; Mayr, Georg W.; Haastert, Peter J.M. van

    1994-01-01

    The micro-organism Dictyostelium uses extracellular cAMP to induce chemotaxis and cell differentiation. Signals are transduced via surface receptors, which activate G proteins, to effector enzymes. The deduced protein sequence of Dictyostelium discoideum phosphabidylinositol-specific phospholipase C

  4. Naringenin is a novel inhibitor of Dictyostelium cell proliferation and cell migration

    International Nuclear Information System (INIS)

    Russ, Misty; Martinez, Raquel; Ali, Hind; Steimle, Paul A.

    2006-01-01

    Naringenin is a flavanone compound that alters critical cellular processes such as cell multiplication, glucose uptake, and mitochondrial activity. In this study, we used the social amoeba, Dictyostelium discoideum, as a model system for examining the cellular processes and signaling pathways affected by naringenin. We found that naringenin inhibited Dictyostelium cell division in a dose-dependent manner (IC 5 ∼ 20 μM). Assays of Dictyostelium chemotaxis and multicellular development revealed that naringenin possesses a previously unrecognized ability to suppress amoeboid cell motility. We also found that naringenin, which is known to inhibit phosphatidylinositol 3-kinase activity, had no apparent effect on phosphatidylinositol 3,4,5-trisphosphate synthesis in live Dictyostelium cells; suggesting that this compound suppresses cell growth and migration via alternative signaling pathways. In another context, the discoveries described here highlight the value of using the Dictyostelium model system for identifying and characterizing the mechanisms by which naringenin, and related compounds, exert their effects on eukaryotic cells

  5. Deletion of Dictyostelium discoideum Sir2A impairs cell proliferation ...

    Indian Academy of Sciences (India)

    Rakhee Lohia

    2018-04-13

    Apr 13, 2018 ... Multicellular structures developed were collected, fixed and stained with X-gal as ... classification for Sirtuins (Fyre 2000), the above were clas- ... RNA, protein and lipid substrates (Klug 1999; Hall 2005;. Gamsjaeger et al.

  6. Cytoplasmic pH and the regulation of the dictyostelium cell cycle

    NARCIS (Netherlands)

    Aerts, R.J.; Durston, A.J.; Moolenaar, W.H.

    1985-01-01

    Cytoplasmic pH (pHl) was monitored during the cell cycle of synchronous populations of Dictyostelium discoideum by means of a pH “null point” method. There is a cycle of pHl that closely corresponds to the DNA replication cycle, with a minimum of pH 7.20 in interphase and a peak of pH 7.45 during S

  7. A flavin-dependent halogenase catalyzes the chlorination step in the biosynthesis of Dictyostelium differentiation-inducing factor 1

    OpenAIRE

    Neumann, Christopher S.; Walsh, Christopher T.; Kay, Robert R.

    2010-01-01

    Differentiation-inducing factor 1 (DIF-1) is a polyketide-derived morphogen which drives stalk cell formation in the developmental cycle of Dictyostelium discoideum. Previous experiments demonstrated that the biosynthetic pathway proceeds via dichlorination of the precursor molecule THPH, but the enzyme responsible for this transformation has eluded characterization. Our recent studies on prokaryotic flavin-dependent halogenases and insights from the sequenced Dd genome led us to a candidate ...

  8. Burkholderia bacteria infectiously induce the proto-farming symbiosis of Dictyostelium amoebae and food bacteria.

    Science.gov (United States)

    DiSalvo, Susanne; Haselkorn, Tamara S; Bashir, Usman; Jimenez, Daniela; Brock, Debra A; Queller, David C; Strassmann, Joan E

    2015-09-08

    Symbiotic associations can allow an organism to acquire novel traits by accessing the genetic repertoire of its partner. In the Dictyostelium discoideum farming symbiosis, certain amoebas (termed "farmers") stably associate with bacterial partners. Farmers can suffer a reproductive cost but also gain beneficial capabilities, such as carriage of bacterial food (proto-farming) and defense against competitors. Farming status previously has been attributed to amoeba genotype, but the role of bacterial partners in its induction has not been examined. Here, we explore the role of bacterial associates in the initiation, maintenance, and phenotypic effects of the farming symbiosis. We demonstrate that two clades of farmer-associated Burkholderia isolates colonize D. discoideum nonfarmers and infectiously endow them with farmer-like characteristics, indicating that Burkholderia symbionts are a major driver of the farming phenomenon. Under food-rich conditions, Burkholderia-colonized amoebas produce fewer spores than uncolonized counterparts, with the severity of this reduction being dependent on the Burkholderia colonizer. However, the induction of food carriage by Burkholderia colonization may be considered a conditionally adaptive trait because it can confer an advantage to the amoeba host when grown in food-limiting conditions. We observed Burkholderia inside and outside colonized D. discoideum spores after fruiting body formation; this observation, together with the ability of Burkholderia to colonize new amoebas, suggests a mixed mode of symbiont transmission. These results change our understanding of the D. discoideum farming symbiosis by establishing that the bacterial partner, Burkholderia, is an important causative agent of the farming phenomenon.

  9. The Dictyostelium Bcr/Abr-related protein DRG regulates both Rac- and Rab-dependent pathways

    OpenAIRE

    Knetsch, Menno L.W.; Schäfers, Nicole; Horstmann, Heinz; Manstein, Dietmar J.

    2001-01-01

    Dictyostelium discoideum DdRacGap1 (DRG) contains both Rho-GEF and Rho-GAP domains, a feature it shares with mammalian Bcr and Abr. To elucidate the physiological role of this multifunctional protein, we characterized the enzymatic activity of recombinant DRG fragments in vitro, created DRG-null cells, and studied the function of the protein in vivo by analysing the phenotypic changes displayed by DRG-depleted cells and DRG-null cells complemented with DRG or DRG fragments. Our results show t...

  10. The Parkinson's disease-associated protein DJ-1 plays a positive nonmitochondrial role in endocytosis in Dictyostelium cells

    Directory of Open Access Journals (Sweden)

    Suwei Chen

    2017-10-01

    Full Text Available The loss of function of DJ-1 caused by mutations in DJ1 causes a form of familial Parkinson's disease (PD. However, the role of DJ-1 in healthy and in PD cells is poorly understood. Even its subcellular localization in mammalian cells is uncertain, with both cytosolic and mitochondrial locations having been reported. We show here that DJ-1 is normally located in the cytoplasm in healthy Dictyostelium discoideum cells. With its unique life cycle, straightforward genotype-phenotype relationships, experimental accessibility and genetic tractability, D. discoideum offers an attractive model to investigate the roles of PD-associated genes. Furthermore, the study of mitochondrial biology, mitochondrial genome transcription and AMP-activated protein kinase-mediated cytopathologies in mitochondrial dysfunction have been well developed in this organism. Unlike mammalian systems, Dictyostelium mitochondrial dysfunction causes a reproducible and readily assayed array of aberrant phenotypes: defective phototaxis, impaired growth, normal rates of endocytosis and characteristic defects in multicellular morphogenesis. This makes it possible to study whether the underlying cytopathological mechanisms of familial PD involve mitochondrial dysfunction. DJ-1 has a single homologue in the Dictyostelium genome. By regulating the expression level of DJ-1 in D. discoideum, we show here that in unstressed cells, DJ-1 is required for normal rates of endocytic nutrient uptake (phagocytosis and, to a lesser extent, pinocytosis and thus growth. Reduced expression of DJ-1 had no effect on phototaxis in the multicellular migratory ‘slug’ stage of the life cycle, but resulted in thickened stalks in the final fruiting bodies. This pattern of phenotypes is distinct from that observed in Dictyostelium to result from mitochondrial dyfunction. Direct measurement of mitochondrial respiratory function in intact cells revealed that DJ-1 knockdown stimulates whereas DJ-1

  11. Targets downstream of Cdk8 in Dictyostelium development

    Directory of Open Access Journals (Sweden)

    Skelton Jason

    2011-01-01

    Full Text Available Abstract Background Cdk8 is a component of the mediator complex which facilitates transcription by RNA polymerase II and has been shown to play an important role in development of Dictyostelium discoideum. This eukaryote feeds as single cells but starvation triggers the formation of a multicellular organism in response to extracellular pulses of cAMP and the eventual generation of spores. Strains in which the gene encoding Cdk8 have been disrupted fail to form multicellular aggregates unless supplied with exogenous pulses of cAMP and later in development, cdk8- cells show a defect in spore production. Results Microarray analysis revealed that the cdk8- strain previously described (cdk8-HL contained genome duplications. Regeneration of the strain in a background lacking detectable gene duplication generated strains (cdk8-2 with identical defects in growth and early development, but a milder defect in spore generation, suggesting that the severity of this defect depends on the genetic background. The failure of cdk8- cells to aggregate unless rescued by exogenous pulses of cAMP is consistent with a failure to express the catalytic subunit of protein kinase A. However, overexpression of the gene encoding this protein was not sufficient to rescue the defect, suggesting that this is not the only important target for Cdk8 at this stage of development. Proteomic analysis revealed two potential targets for Cdk8 regulation, one regulated post-transcriptionally (4-hydroxyphenylpyruvate dioxygenase (HPD and one transcriptionally (short chain dehydrogenase/reductase (SDR1. Conclusions This analysis has confirmed the importance of Cdk8 at multiple stages of Dictyostelium development, although the severity of the defect in spore production depends on the genetic background. Potential targets of Cdk8-mediated gene regulation have been identified in Dictyostelium which will allow the mechanism of Cdk8 action and its role in development to be determined.

  12. Variation in the excitability of developed D. discoideum cells as a function of agar concentration in the substrate

    Science.gov (United States)

    Oikawa, Noriko; Bae, Albert; Amselem, Gabriel; Bodenschatz, Eberhard

    2010-03-01

    In the absence of nutrients, Dictyostelium discoideum cells enter a developmental cycle--they signal each other, aggregate, and ultimately form fruiting bodies. During the signaling stage, the cells relay waves of cyclic adenosine 3',5' monophosphate (cAMP). We observed a transition from spiral to circular patterns in the signaling wave, depending on the agar concentration of the substrate. In this talk we will present the changes in the times for the onset of signaling and synchronization versus agar concentration, as measured by spectral entropy. We also will discuss the origin of these effects.

  13. Predicting the distribution of spiral waves from cell properties in a developmental-path model of Dictyostelium pattern formation.

    Directory of Open Access Journals (Sweden)

    Daniel Geberth

    2009-07-01

    Full Text Available The slime mold Dictyostelium discoideum is one of the model systems of biological pattern formation. One of the most successful answers to the challenge of establishing a spiral wave pattern in a colony of homogeneously distributed D. discoideum cells has been the suggestion of a developmental path the cells follow (Lauzeral and coworkers. This is a well-defined change in properties each cell undergoes on a longer time scale than the typical dynamics of the cell. Here we show that this concept leads to an inhomogeneous and systematic spatial distribution of spiral waves, which can be predicted from the distribution of cells on the developmental path. We propose specific experiments for checking whether such systematics are also found in data and thus, indirectly, provide evidence of a developmental path.

  14. The ROCO Kinase QkgA Is Necessary for Proliferation Inhibition by Autocrine Signals in Dictyostelium discoideum▿

    OpenAIRE

    Phillips, Jonathan E.; Gomer, Richard H.

    2010-01-01

    AprA and CfaD are secreted proteins that function as autocrine signals to inhibit cell proliferation in Dictyostelium discoideum. Cells lacking AprA or CfaD proliferate rapidly, and adding AprA or CfaD to cells slows proliferation. Cells lacking the ROCO kinase QkgA proliferate rapidly, with a doubling time 83% of that of the wild type, and overexpression of a QkgA-green fluorescent protein (GFP) fusion protein slows cell proliferation. We found that qkgA− cells accumulate normal levels of ex...

  15. Two distinct sensing pathways allow recognition of Klebsiella pneumoniae by Dictyostelium amoebae.

    Science.gov (United States)

    Lima, Wanessa C; Balestrino, Damien; Forestier, Christiane; Cosson, Pierre

    2014-03-01

    Recognition of bacteria by metazoans is mediated by receptors that recognize different types of microorganisms and elicit specific cellular responses. The soil amoebae Dictyostelium discoideum feeds upon a variable mixture of environmental bacteria, and it is expected to recognize and adapt to various food sources. To date, however, no bacteria-sensing mechanisms have been described. In this study, we isolated a Dictyostelium mutant (fspA KO) unable to grow in the presence of non-capsulated Klebsiella pneumoniae bacteria, but growing as efficiently as wild-type cells in the presence of other bacteria, such as Bacillus subtilis. fspA KO cells were also unable to respond to K. pneumoniae and more specifically to bacterially secreted folate in a chemokinetic assay, while they responded readily to B. subtilis. Remarkably, both WT and fspA KO cells were able to grow in the presence of capsulated LM21 K. pneumoniae, and responded to purified capsule, indicating that capsule recognition may represent an alternative, FspA-independent mechanism for K. pneumoniae sensing. When LM21 capsule synthesis genes were deleted, growth and chemokinetic response were lost for fspA KO cells, but not for WT cells. Altogether, these results indicate that Dictyostelium amoebae use specific recognition mechanisms to respond to different K. pneumoniae elements. © 2013 John Wiley & Sons Ltd.

  16. Control of cyclin C levels during development of Dictyostelium.

    Directory of Open Access Journals (Sweden)

    David M Greene

    2010-05-01

    Full Text Available Cdk8 and its partner cyclin C form part of the mediator complex which links the basal transcription machinery to regulatory proteins. The pair are required for correct regulation of a subset of genes and have been implicated in control of development in a number of organisms including the social amoeba Dictyostelium discoideum. When feeding, Dictyostelium amoebae are unicellular but upon starvation they aggregate to form a multicellular structure which develops into a fruiting body containing spores. Cells in which the gene encoding Cdk8 has been deleted fail to enter aggregates due to a failure of early gene expression.We have monitored the expression levels of cyclin C protein during development and find levels decrease after the multicellular mound is formed. This decrease is triggered by extracellular cAMP that, in turn, is working in part through an increase in intracellular cAMP. The loss of cyclin C is coincident with a reduction in the association of Cdk8 with a high molecular weight complex in the nucleus. Overexpression of cyclin C and Cdk8 lead to an increased rate of early development, consistent with the levels being rate limiting.Overall these results show that both cyclin C and Cdk8 are regulated during development in response to extracellular signals and the levels of these proteins are important in controlling the timing of developmental processes. These findings have important implications for the role of these proteins in controlling development, suggesting that they are targets for developmental signals to regulate gene expression.

  17. Acanthamoeba and Dictyostelium as Cellular Models for Legionella Infection

    Science.gov (United States)

    Swart, A. Leoni; Harrison, Christopher F.; Eichinger, Ludwig; Steinert, Michael; Hilbi, Hubert

    2018-01-01

    Environmental bacteria of the genus Legionella naturally parasitize free-living amoebae. Upon inhalation of bacteria-laden aerosols, the opportunistic pathogens grow intracellularly in alveolar macrophages and can cause a life-threatening pneumonia termed Legionnaires' disease. Intracellular replication in amoebae and macrophages takes place in a unique membrane-bound compartment, the Legionella-containing vacuole (LCV). LCV formation requires the bacterial Icm/Dot type IV secretion system, which translocates literally hundreds of “effector” proteins into host cells, where they modulate crucial cellular processes for the pathogen's benefit. The mechanism of LCV formation appears to be evolutionarily conserved, and therefore, amoebae are not only ecologically significant niches for Legionella spp., but also useful cellular models for eukaryotic phagocytes. In particular, Acanthamoeba castellanii and Dictyostelium discoideum emerged over the last years as versatile and powerful models. Using genetic, biochemical and cell biological approaches, molecular interactions between amoebae and Legionella pneumophila have recently been investigated in detail with a focus on the role of phosphoinositide lipids, small and large GTPases, autophagy components and the retromer complex, as well as on bacterial effectors targeting these host factors. PMID:29552544

  18. Acanthamoeba and Dictyostelium as Cellular Models for Legionella Infection

    Directory of Open Access Journals (Sweden)

    A. Leoni Swart

    2018-03-01

    Full Text Available Environmental bacteria of the genus Legionella naturally parasitize free-living amoebae. Upon inhalation of bacteria-laden aerosols, the opportunistic pathogens grow intracellularly in alveolar macrophages and can cause a life-threatening pneumonia termed Legionnaires' disease. Intracellular replication in amoebae and macrophages takes place in a unique membrane-bound compartment, the Legionella-containing vacuole (LCV. LCV formation requires the bacterial Icm/Dot type IV secretion system, which translocates literally hundreds of “effector” proteins into host cells, where they modulate crucial cellular processes for the pathogen's benefit. The mechanism of LCV formation appears to be evolutionarily conserved, and therefore, amoebae are not only ecologically significant niches for Legionella spp., but also useful cellular models for eukaryotic phagocytes. In particular, Acanthamoeba castellanii and Dictyostelium discoideum emerged over the last years as versatile and powerful models. Using genetic, biochemical and cell biological approaches, molecular interactions between amoebae and Legionella pneumophila have recently been investigated in detail with a focus on the role of phosphoinositide lipids, small and large GTPases, autophagy components and the retromer complex, as well as on bacterial effectors targeting these host factors.

  19. Functional similarities between the dictyostelium protein AprA and the human protein dipeptidyl-peptidase IV.

    Science.gov (United States)

    Herlihy, Sarah E; Tang, Yu; Phillips, Jonathan E; Gomer, Richard H

    2017-03-01

    Autocrine proliferation repressor protein A (AprA) is a protein secreted by Dictyostelium discoideum cells. Although there is very little sequence similarity between AprA and any human protein, AprA has a predicted structural similarity to the human protein dipeptidyl peptidase IV (DPPIV). AprA is a chemorepellent for Dictyostelium cells, and DPPIV is a chemorepellent for neutrophils. This led us to investigate if AprA and DPPIV have additional functional similarities. We find that like AprA, DPPIV is a chemorepellent for, and inhibits the proliferation of, D. discoideum cells, and that AprA binds some DPPIV binding partners such as fibronectin. Conversely, rAprA has DPPIV-like protease activity. These results indicate a functional similarity between two eukaryotic chemorepellent proteins with very little sequence similarity, and emphasize the usefulness of using a predicted protein structure to search a protein structure database, in addition to searching for proteins with similar sequences. © 2016 The Protein Society.

  20. Functional similarities between the dictyostelium protein AprA and the human protein dipeptidyl‐peptidase IV

    Science.gov (United States)

    Herlihy, Sarah E.; Tang, Yu; Phillips, Jonathan E.

    2017-01-01

    Abstract Autocrine proliferation repressor protein A (AprA) is a protein secreted by Dictyostelium discoideum cells. Although there is very little sequence similarity between AprA and any human protein, AprA has a predicted structural similarity to the human protein dipeptidyl peptidase IV (DPPIV). AprA is a chemorepellent for Dictyostelium cells, and DPPIV is a chemorepellent for neutrophils. This led us to investigate if AprA and DPPIV have additional functional similarities. We find that like AprA, DPPIV is a chemorepellent for, and inhibits the proliferation of, D. discoideum cells, and that AprA binds some DPPIV binding partners such as fibronectin. Conversely, rAprA has DPPIV‐like protease activity. These results indicate a functional similarity between two eukaryotic chemorepellent proteins with very little sequence similarity, and emphasize the usefulness of using a predicted protein structure to search a protein structure database, in addition to searching for proteins with similar sequences. PMID:28028841

  1. dictyExpress: a web-based platform for sequence data management and analytics in Dictyostelium and beyond.

    Science.gov (United States)

    Stajdohar, Miha; Rosengarten, Rafael D; Kokosar, Janez; Jeran, Luka; Blenkus, Domen; Shaulsky, Gad; Zupan, Blaz

    2017-06-02

    Dictyostelium discoideum, a soil-dwelling social amoeba, is a model for the study of numerous biological processes. Research in the field has benefited mightily from the adoption of next-generation sequencing for genomics and transcriptomics. Dictyostelium biologists now face the widespread challenges of analyzing and exploring high dimensional data sets to generate hypotheses and discovering novel insights. We present dictyExpress (2.0), a web application designed for exploratory analysis of gene expression data, as well as data from related experiments such as Chromatin Immunoprecipitation sequencing (ChIP-Seq). The application features visualization modules that include time course expression profiles, clustering, gene ontology enrichment analysis, differential expression analysis and comparison of experiments. All visualizations are interactive and interconnected, such that the selection of genes in one module propagates instantly to visualizations in other modules. dictyExpress currently stores the data from over 800 Dictyostelium experiments and is embedded within a general-purpose software framework for management of next-generation sequencing data. dictyExpress allows users to explore their data in a broader context by reciprocal linking with dictyBase-a repository of Dictyostelium genomic data. In addition, we introduce a companion application called GenBoard, an intuitive graphic user interface for data management and bioinformatics analysis. dictyExpress and GenBoard enable broad adoption of next generation sequencing based inquiries by the Dictyostelium research community. Labs without the means to undertake deep sequencing projects can mine the data available to the public. The entire information flow, from raw sequence data to hypothesis testing, can be accomplished in an efficient workspace. The software framework is generalizable and represents a useful approach for any research community. To encourage more wide usage, the backend is open

  2. EDTA treatment alters protein glycosylation in the cellular slime mold Dictyostelium discoideum

    International Nuclear Information System (INIS)

    West, C.M.; Brownstein, S.A.

    1988-01-01

    The authors have found that treatment of cells with EDTA resulted in the accumulation of lower molecular weight forms of two cell-type-specific glycoproteins. These new glycoproteins lacked a developmentally regulated glycoantigen defined by monoclonal antibody 54.2. Since EDTA dissociated the cells, the possible involvement of cell separation was tested by immobilizing cells in soft agarose. Glycoantigen expression on these proteins was found to be dependent on cAMP and high oxygen tension but not on cell contact, and was reversibly sensitive to EDTA regardless of the state of cell association. The EDTA effect was mimicked by other soluble, but not particulate, membrane impermeable chelators, could be completed by Zn 2+ better than Mg 2+ , and appeared to involve an intracellular mechanism. Studies with [ 14 C]EDTA showed that EDTA equilibrated with a cellular compartment in a temperature-dependent, Zn 2+ -insensitive fashion with half-time kinetics of loading and unloading of 30-40 min. The data suggest that this step in glycosylation, which was found to be delayed 1 or more hours subsequent to protein synthesis, involves an intracellular, transition metal-ion-dependent process which can be modulated by chelators entering the cell through the endocytic pathway

  3. Evidence that a glycolipid tail anchors antigen 117 to the plasma membrane of Dictyostelium discoideum cells

    International Nuclear Information System (INIS)

    Sadeghi, H.; Da Silva, A.M.; Klein, C.

    1988-01-01

    The authors describe the biochemical features of the putative cell cohesion molecule antigen 117, indicating that it is anchored to the plasma membrane by a glycolipid tail. Antigen 117 can be radiolabeled with [ 3 H]myristate, [ 3 H]palmitate, and [ 14 C]ethanolamine. The fatty acid label is removed by periodate oxidation and nitrous acid deamination, indicating that the fatty acid is attached to the protein by a structure containing carbohydrate and an unsubstituted glucosamine. As cells develop aggregation competence, the antigen is released from the cell surface in a soluble form that can still be radiolabeled with [ 14 C]ethanolamine but not with [ 3 H]myristate of [ 3 H]-palmitate. The molecular weight of the released antigen is similar to that found in the plasma membrane, but it preferentially partitions in Triton X-114 as a hydrophilic, as opposed to a hydrophobic, protein. Plasma membranes contain the enzyme activity responsible for the release of the antigen in a soluble form

  4. Lithium ions induce prestalk-associated gene expression and inhibit prespore gene expression in Dictyostelium discoideum

    NARCIS (Netherlands)

    Peters, Dorien J.M.; Lookeren Campagne, Michiel M. van; Haastert, Peter J.M. van; Spek, Wouter; Schaap, Pauline

    1989-01-01

    We investigated the effect of Li+ on two types of cyclic AMP-regulated gene expression and on basal and cyclic AMP-stimulated inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) levels. Li+ effectively inhibits cyclic AMP-induced prespore gene expression, half-maximal inhibition occurring at about 2mM-LiCl.

  5. Effects of caffeine on DNA repair of UV-irradiated Dictyostelium discoideum

    International Nuclear Information System (INIS)

    Ohnishi, T.; Okaichi, K.; Ohashi, Y.; Nozu, K.

    1981-01-01

    Caffeine enhances the UV-killing of amoeboid cells of NC-4, but UV-irradiated γs-13 is insensitive to caffeine. UV-irradiated NC-4 becomes insensitive to the effect of caffeine during a postirradiation incubation in buffer for about 90 min, but γs-13 remains unchanged in the sensitivity to caffeine throughout the incubation for 180 min. Amoeboid cells of γs-13 can remove pyrimidine dimers as well as NC-4 even in the presence of caffeine. Caffeine inhibits rejoining of strand-breaks of DNA in UV-irradiated NC-4, but the rejoining in γs-13 is insensitive to caffeine. (author)

  6. Comparing the Dictyostelium and Entamoeba genomes reveals an ancient split in the Conosa lineage.

    Directory of Open Access Journals (Sweden)

    Jie Song

    2005-12-01

    Full Text Available The Amoebozoa are a sister clade to the fungi and the animals, but are poorly sampled for completely sequenced genomes. The social amoeba Dictyostelium discoideum and amitochondriate pathogen Entamoeba histolytica are the first Amoebozoa with genomes completely sequenced. Both organisms are classified under the Conosa subphylum. To identify Amoebozoa-specific genomic elements, we compared these two genomes to each other and to other eukaryotic genomes. An expanded phylogenetic tree built from the complete predicted proteomes of 23 eukaryotes places the two amoebae in the same lineage, although the divergence is estimated to be greater than that between animals and fungi, and probably happened shortly after the Amoebozoa split from the opisthokont lineage. Most of the 1,500 orthologous gene families shared between the two amoebae are also shared with plant, animal, and fungal genomes. We found that only 42 gene families are distinct to the amoeba lineage; among these are a large number of proteins that contain repeats of the FNIP domain, and a putative transcription factor essential for proper cell type differentiation in D. discoideum. These Amoebozoa-specific genes may be useful in the design of novel diagnostics and therapies for amoebal pathologies.

  7. A Dictyostelium secreted factor requires a PTEN-like phosphatase to slow proliferation and induce chemorepulsion.

    Directory of Open Access Journals (Sweden)

    Sarah E Herlihy

    Full Text Available In Dictyostelium discoideum, AprA and CfaD are secreted proteins that inhibit cell proliferation. We found that the proliferation of cells lacking CnrN, a phosphatase and tensin homolog (PTEN-like phosphatase, is not inhibited by exogenous AprA and is increased by exogenous CfaD. The expression of CnrN in cnrN cells partially rescues these altered sensitivities, suggesting that CnrN is necessary for the ability of AprA and CfaD to inhibit proliferation. Cells lacking CnrN accumulate normal levels of AprA and CfaD. Like cells lacking AprA and CfaD, cnrN cells proliferate faster and reach a higher maximum cell density than wild type cells, tend to be multinucleate, accumulate normal levels of mass and protein per nucleus, and form less viable spores. When cnrN cells expressing myc-tagged CnrN are stimulated with a mixture of rAprA and rCfaD, levels of membrane-associated myc-CnrN increase. AprA also causes chemorepulsion of Dictyostelium cells, and CnrN is required for this process. Combined, these results suggest that CnrN functions in a signal transduction pathway downstream of AprA and CfaD mediating some, but not all, of the effects of AprA and CfaD.

  8. A Dictyostelium secreted factor requires a PTEN-like phosphatase to slow proliferation and induce chemorepulsion.

    Science.gov (United States)

    Herlihy, Sarah E; Tang, Yitai; Gomer, Richard H

    2013-01-01

    In Dictyostelium discoideum, AprA and CfaD are secreted proteins that inhibit cell proliferation. We found that the proliferation of cells lacking CnrN, a phosphatase and tensin homolog (PTEN)-like phosphatase, is not inhibited by exogenous AprA and is increased by exogenous CfaD. The expression of CnrN in cnrN cells partially rescues these altered sensitivities, suggesting that CnrN is necessary for the ability of AprA and CfaD to inhibit proliferation. Cells lacking CnrN accumulate normal levels of AprA and CfaD. Like cells lacking AprA and CfaD, cnrN cells proliferate faster and reach a higher maximum cell density than wild type cells, tend to be multinucleate, accumulate normal levels of mass and protein per nucleus, and form less viable spores. When cnrN cells expressing myc-tagged CnrN are stimulated with a mixture of rAprA and rCfaD, levels of membrane-associated myc-CnrN increase. AprA also causes chemorepulsion of Dictyostelium cells, and CnrN is required for this process. Combined, these results suggest that CnrN functions in a signal transduction pathway downstream of AprA and CfaD mediating some, but not all, of the effects of AprA and CfaD.

  9. Gene discovery by chemical mutagenesis and whole-genome sequencing in Dictyostelium.

    Science.gov (United States)

    Li, Cheng-Lin Frank; Santhanam, Balaji; Webb, Amanda Nicole; Zupan, Blaž; Shaulsky, Gad

    2016-09-01

    Whole-genome sequencing is a useful approach for identification of chemical-induced lesions, but previous applications involved tedious genetic mapping to pinpoint the causative mutations. We propose that saturation mutagenesis under low mutagenic loads, followed by whole-genome sequencing, should allow direct implication of genes by identifying multiple independent alleles of each relevant gene. We tested the hypothesis by performing three genetic screens with chemical mutagenesis in the social soil amoeba Dictyostelium discoideum Through genome sequencing, we successfully identified mutant genes with multiple alleles in near-saturation screens, including resistance to intense illumination and strong suppressors of defects in an allorecognition pathway. We tested the causality of the mutations by comparison to published data and by direct complementation tests, finding both dominant and recessive causative mutations. Therefore, our strategy provides a cost- and time-efficient approach to gene discovery by integrating chemical mutagenesis and whole-genome sequencing. The method should be applicable to many microbial systems, and it is expected to revolutionize the field of functional genomics in Dictyostelium by greatly expanding the mutation spectrum relative to other common mutagenesis methods. © 2016 Li et al.; Published by Cold Spring Harbor Laboratory Press.

  10. Nanovesicles released by Dictyostelium cells: a potential carrier for drug delivery.

    Science.gov (United States)

    Lavialle, Françoise; Deshayes, Sophie; Gonnet, Florence; Larquet, Eric; Kruglik, Sergei G; Boisset, Nicolas; Daniel, Régis; Alfsen, Annette; Tatischeff, Irène

    2009-10-01

    Nanovesicles released by Dictyostelium discoideum cells grown in the presence of the DNA-specific dye Hoechst 33342 have been previously shown to mediate the transfer of the dye into the nuclei of Hoechst-resistant cells. The present investigation extends this work by conducting experiments in the presence of hypericin, a fluorescent therapeutic photosensitizer assayed for antitumoral photodynamic therapy. Nanovesicles released by Dictyostelium cells exhibit an averaged diameter between 50 and 150 nm, as measured by transmission cryoelectron microscopy. A proteomic analysis reveals a predominance of actin and actin-related proteins. The detection of a lysosomal membrane protein (LIMP II) indicates that these vesicles are likely generated in the late endosomal compartment. The use of the hypericin-containing nanovesicles as nanodevices for in vitro drug delivery was investigated by fluorescence microscopy. The observed signal was almost exclusively located in the perinuclear area of two human cell lines, skin fibroblasts (HS68) and cervix carcinoma (HeLa) cells. Studies by confocal microscopy with specific markers of cell organelles, provided evidence that hypericin was accumulated in the Golgi apparatus. All these data shed a new light on in vitro drug delivery by using cell-released vesicles as carriers.

  11. Determination of inositol 1,4,5-trisphosphate levels in Dictyostelium by isotope dilution assay

    International Nuclear Information System (INIS)

    Van Haastert, P.J.

    1989-01-01

    A commercial isotope dilution assay was used for the determination of Ins(1,4,5)P3 levels in the microorganism Dictyostelium discoideum. Cross-reactivity in the assay was detected with extracts from cells and the medium. The compound which induced this cross-reactivity was tentatively identified as Ins(1,4,5)P3 by (i) codegradation with authentic [ 32 P]Ins(1,4,5)P3 by three specific Ins(1,4,5)P3 phosphatases, and (ii) co-chromatography with authentic [ 32 P]Ins(1,4,5)P3 on HPLC columns. The cellular concentration was estimated as 165 +/- 42 pmol/10(8) cells, yielding a mean intracellular Ins(1,4,5)P3 concentration of 3.3 microM. Dictyostelium cells secrete large amounts of Ins(1,4,5)P3 at a rate of about 10% of the cellular content per minute, yielding about 0.13 microM extracellular Ins(1,4,5)P3 after 15 min in a suspension of 10(8) cells/ml. The chemoattractant cAMP induced a transient increase of the Ins(1,4,5)P3 concentration; the data suggest an intracacellular rise from 3.3 to 5.5 microM with a maximum at 6 s after stimulation

  12. Differentiation-inducing factor-1 and -2 function also as modulators for Dictyostelium chemotaxis.

    Directory of Open Access Journals (Sweden)

    Hidekazu Kuwayama

    Full Text Available BACKGROUND: In the early stages of development of the cellular slime mold Dictyostelium discoideum, chemotaxis toward cAMP plays a pivotal role in organizing discrete cells into a multicellular structure. In this process, a series of signaling molecules, such as G-protein-coupled cell surface receptors for cAMP, phosphatidylinositol metabolites, and cyclic nucleotides, function as the signal transducers for controlling dynamics of cytoskeleton. Differentiation-inducing factor-1 and -2 (DIF-1 and DIF-2 were originally identified as the factors (chlorinated alkylphenones that induce Dictyostelium stalk cell differentiation, but it remained unknown whether the DIFs had any other physiologic functions. METHODOLOGY/PRINCIPAL FINDINGS: To further elucidate the functions of DIFs, in the present study we investigated their effects on chemotaxis under various conditions. Quite interestingly, in shallow cAMP gradients, DIF-1 suppressed chemotaxis whereas DIF-2 promoted it greatly. Analyses with various mutants revealed that DIF-1 may inhibit chemotaxis, at least in part, via GbpB (a phosphodiesterase and a decrease in the intracellular cGMP concentration ([cGMP](i. DIF-2, by contrast, may enhance chemotaxis, at least in part, via RegA (another phosphodiesterase and an increase in [cGMP](i. Using null mutants for DimA and DimB, the transcription factors that are required for DIF-dependent prestalk differentiation, we also showed that the mechanisms for the modulation of chemotaxis by DIFs differ from those for the induction of cell differentiation by DIFs, at least in part. CONCLUSIONS/SIGNIFICANCE: Our findings indicate that DIF-1 and DIF-2 function as negative and positive modulators for Dictyostelium chemotaxis, respectively. To our knowledge, this is the first report in any organism of physiologic modulators (small molecules for chemotaxis having differentiation-inducing activity.

  13. BTG interacts with retinoblastoma to control cell fate in Dictyostelium.

    Directory of Open Access Journals (Sweden)

    Daniele Conte

    Full Text Available BACKGROUND: In the genesis of many tissues, a phase of cell proliferation is followed by cell cycle exit and terminal differentiation. The latter two processes overlap: genes involved in the cessation of growth may also be important in triggering differentiation. Though conceptually distinct, they are often causally related and functional interactions between the cell cycle machinery and cell fate control networks are fundamental to coordinate growth and differentiation. A switch from proliferation to differentiation may also be important in the life cycle of single-celled organisms, and genes which arose as regulators of microbial differentiation may be conserved in higher organisms. Studies in microorganisms may thus contribute to understanding the molecular links between cell cycle machinery and the determination of cell fate choice networks. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that in the amoebozoan D. discoideum, an ortholog of the metazoan antiproliferative gene btg controls cell fate, and that this function is dependent on the presence of a second tumor suppressor ortholog, the retinoblastoma-like gene product. Specifically, we find that btg-overexpressing cells preferentially adopt a stalk cell (and, more particularly, an Anterior-Like Cell fate. No btg-dependent preference for ALC fate is observed in cells in which the retinoblastoma-like gene has been genetically inactivated. Dictyostelium btg is the only example of non-metazoan member of the BTG family characterized so far, suggesting that a genetic interaction between btg and Rb predated the divergence between dictyostelids and metazoa. CONCLUSIONS/SIGNIFICANCE: While the requirement for retinoblastoma function for BTG antiproliferative activity in metazoans is known, an interaction of these genes in the control of cell fate has not been previously documented. Involvement of a single pathway in the control of mutually exclusive processes may have relevant implication in the

  14. An unusual protein kinase phosphorylates the chemotactic receptor of Dictystelium discoideum

    International Nuclear Information System (INIS)

    Meier, K.; Klein, C.

    1988-01-01

    The authors report the cAMP-dependent phosphorylation of the chemotactic receptor of Dictyostelium discoideum in partially purified plasma membranes. The protein kinase responsible for receptor phosphorylation is associated with this fraction and preferentially phosphorylates the ligand-occupied form of the receptor. 8-Azido[ 32 P]cAMP labeling of the cell surface has shown that the cAMP receptor exists in two forms. A 45-kDa protein is predominant on unstimulated cells. cAMP stimulation results in an increased receptor phosphorylation such that the receptor migrates on NaDodSO 4 /PAGE as a 47-kDa protein. Phosphorylation of the chemotactic receptor is not detected in membrane preparations unless cAMP is added to the incubation mixture. Only under those conditions is the phosphorylated 47-kDa form observed. The requirement for cAMP reflects the fact that the kinase involved preferentially uses the ligand-occupied receptor as a substrate. In vitro phosphorylation of the receptor does not involve tyrosine residues. The enzyme does not appear to be a cAMP- or cGMP-dependent protein kinase nor is it sensitive to guanine nucleotides, Ca 2+ /calmodulin, Ca 2+ /phospholipid, or EGTA. Similarities with the β-adrenergic receptor protein kinase are discussed

  15. A flavin-dependent halogenase catalyzes the chlorination step in the biosynthesis of Dictyostelium differentiation-inducing factor 1.

    Science.gov (United States)

    Neumann, Christopher S; Walsh, Christopher T; Kay, Robert R

    2010-03-30

    Differentiation-inducing factor 1 (DIF-1) is a polyketide-derived morphogen which drives stalk cell formation in the developmental cycle of Dictyostelium discoideum. Previous experiments demonstrated that the biosynthetic pathway proceeds via dichlorination of the precursor molecule THPH, but the enzyme responsible for this transformation has eluded characterization. Our recent studies on prokaryotic flavin-dependent halogenases and insights from the sequenced Dd genome led us to a candidate gene for this transformation. In this work, we present in vivo and in vitro evidence that chlA from Dd encodes a flavin-dependent halogenase capable of catalyzing both chlorinations in the biosynthesis of DIF-1. The results provide in vitro characterization of a eukaryotic oxygen-dependent halogenase and demonstrate a broad reach in biology for this molecular tailoring strategy, notably its involvement in the differentiation program of a social amoeba.

  16. Desynchronization of cells on the developmental path triggers the formation of spiral waves of cAMP during Dictyostelium aggregation.

    Science.gov (United States)

    Lauzeral, J; Halloy, J; Goldbeter, A

    1997-08-19

    Whereas it is relatively easy to account for the formation of concentric (target) waves of cAMP in the course of Dictyostelium discoideum aggregation after starvation, the origin of spiral waves remains obscure. We investigate a physiologically plausible mechanism for the spontaneous formation of spiral waves of cAMP in D. discoideum. The scenario relies on the developmental path associated with the continuous changes in the activity of enzymes such as adenylate cyclase and phosphodiesterase observed during the hours that follow starvation. These changes bring the cells successively from a nonexcitable state to an excitable state in which they relay suprathreshold cAMP pulses, and then to autonomous oscillations of cAMP, before the system returns to an excitable state. By analyzing a model for cAMP signaling based on receptor desensitization, we show that the desynchronization of cells on this developmental path triggers the formation of fully developed spirals of cAMP. Developmental paths that do not correspond to the sequence of dynamic transitions no relay-relay-oscillations-relay are less able or fail to give rise to the formation of spirals.

  17. The carboxy-terminal domain of Dictyostelium C-module-binding factor is an independent gene regulatory entity.

    Directory of Open Access Journals (Sweden)

    Jörg Lucas

    Full Text Available The C-module-binding factor (CbfA is a multidomain protein that belongs to the family of jumonji-type (JmjC transcription regulators. In the social amoeba Dictyostelium discoideum, CbfA regulates gene expression during the unicellular growth phase and multicellular development. CbfA and a related D. discoideum CbfA-like protein, CbfB, share a paralogous domain arrangement that includes the JmjC domain, presumably a chromatin-remodeling activity, and two zinc finger-like (ZF motifs. On the other hand, the CbfA and CbfB proteins have completely different carboxy-terminal domains, suggesting that the plasticity of such domains may have contributed to the adaptation of the CbfA-like transcription factors to the rapid genome evolution in the dictyostelid clade. To support this hypothesis we performed DNA microarray and real-time RT-PCR measurements and found that CbfA regulates at least 160 genes during the vegetative growth of D. discoideum cells. Functional annotation of these genes revealed that CbfA predominantly controls the expression of gene products involved in housekeeping functions, such as carbohydrate, purine nucleoside/nucleotide, and amino acid metabolism. The CbfA protein displays two different mechanisms of gene regulation. The expression of one set of CbfA-dependent genes requires at least the JmjC/ZF domain of the CbfA protein and thus may depend on chromatin modulation. Regulation of the larger group of genes, however, does not depend on the entire CbfA protein and requires only the carboxy-terminal domain of CbfA (CbfA-CTD. An AT-hook motif located in CbfA-CTD, which is known to mediate DNA binding to A+T-rich sequences in vitro, contributed to CbfA-CTD-dependent gene regulatory functions in vivo.

  18. Phospholipase Cδ regulates germination of Dictyostelium spores

    NARCIS (Netherlands)

    Dijken, Peter van; Haastert, Peter J.M. van

    2001-01-01

    Background: Many eukaryotes, including plants and fungi make spores that resist severe environmental stress. The micro-organism Dictyostelium contains a single phospholipase C gene (PLC); deletion of the gene has no effect on growth, cell movement and differentiation. In this report we show that PLC

  19. Dicty_cDB: AFM869 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available Dictyostelium discoideum slug cDNA, clone SLH341. 404 e-128 3 ( AF305060 ) Dictyostelium discoideum Wiscott-...ucing significant alignments: (bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott-

  20. A comparative sequence analysis reveals a common GBD/FH3-FH1-FH2-DAD architecture in formins from Dictyostelium, fungi and metazoa

    Directory of Open Access Journals (Sweden)

    Uyeda Taro QP

    2005-03-01

    Full Text Available Abstract Background Formins are multidomain proteins defined by a conserved FH2 (formin homology 2 domain with actin nucleation activity preceded by a proline-rich FH1 (formin homology 1 domain. Formins act as profilin-modulated processive actin nucleators conserved throughout a wide range of eukaryotes. Results We present a detailed sequence analysis of the 10 formins (ForA to J identified in the genome of the social amoeba Dictyostelium discoideum. With the exception of ForI and ForC all other formins conform to the domain structure GBD/FH3-FH1-FH2-DAD, where DAD is the Diaphanous autoinhibition domain and GBD/FH3 is the Rho GTPase-binding domain/formin homology 3 domain that we propose to represent a single domain. ForC lacks a FH1 domain, ForI lacks recognizable GBD/FH3 and DAD domains and ForA, E and J have additional unique domains. To establish the relationship between formins of Dictyostelium and other organisms we constructed a phylogenetic tree based on the alignment of FH2 domains. Real-time PCR was used to study the expression pattern of formin genes. Expression of forC, D, I and J increased during transition to multi-cellular stages, while the rest of genes displayed less marked developmental variations. During sexual development, expression of forH and forI displayed a significant increase in fusion competent cells. Conclusion Our analysis allows some preliminary insight into the functionality of Dictyostelium formins: all isoforms might display actin nucleation activity and, with the exception of ForI, might also be susceptible to autoinhibition and to regulation by Rho GTPases. The architecture GBD/FH3-FH1-FH2-DAD appears common to almost all Dictyostelium, fungal and metazoan formins, for which we propose the denomination of conventional formins, and implies a common regulatory mechanism.

  1. A comparative sequence analysis reveals a common GBD/FH3-FH1-FH2-DAD architecture in formins from Dictyostelium, fungi and metazoa.

    Science.gov (United States)

    Rivero, Francisco; Muramoto, Tetsuya; Meyer, Ann-Kathrin; Urushihara, Hideko; Uyeda, Taro Q P; Kitayama, Chikako

    2005-03-01

    Formins are multidomain proteins defined by a conserved FH2 (formin homology 2) domain with actin nucleation activity preceded by a proline-rich FH1 (formin homology 1) domain. Formins act as profilin-modulated processive actin nucleators conserved throughout a wide range of eukaryotes. We present a detailed sequence analysis of the 10 formins (ForA to J) identified in the genome of the social amoeba Dictyostelium discoideum. With the exception of ForI and ForC all other formins conform to the domain structure GBD/FH3-FH1-FH2-DAD, where DAD is the Diaphanous autoinhibition domain and GBD/FH3 is the Rho GTPase-binding domain/formin homology 3 domain that we propose to represent a single domain. ForC lacks a FH1 domain, ForI lacks recognizable GBD/FH3 and DAD domains and ForA, E and J have additional unique domains. To establish the relationship between formins of Dictyostelium and other organisms we constructed a phylogenetic tree based on the alignment of FH2 domains. Real-time PCR was used to study the expression pattern of formin genes. Expression of forC, D, I and J increased during transition to multi-cellular stages, while the rest of genes displayed less marked developmental variations. During sexual development, expression of forH and forI displayed a significant increase in fusion competent cells. Our analysis allows some preliminary insight into the functionality of Dictyostelium formins: all isoforms might display actin nucleation activity and, with the exception of ForI, might also be susceptible to autoinhibition and to regulation by Rho GTPases. The architecture GBD/FH3-FH1-FH2-DAD appears common to almost all Dictyostelium, fungal and metazoan formins, for which we propose the denomination of conventional formins, and implies a common regulatory mechanism.

  2. Activation of G-proteins by receptor-stimulated nucleoside diphosphate kinase in Dictyostelium.

    Science.gov (United States)

    Bominaar, A A; Molijn, A C; Pestel, M; Veron, M; Van Haastert, P J

    1993-01-01

    Recently, interest in the enzyme nucleoside diphosphate kinase (EC2.7.4.6) has increased as a result of its possible involvement in cell proliferation and development. Since NDP kinase is one of the major sources of GTP in cells, it has been suggested that the effects of an altered NDP kinase activity on cellular processes might be the result of altered transmembrane signal transduction via guanine nucleotide-binding proteins (G-proteins). In the cellular slime mould Dictyostelium discoideum, extracellular cAMP induces an increase of phospholipase C activity via a surface cAMP receptor and G-proteins. In this paper it is demonstrated that part of the cellular NDP kinase is associated with the membrane and stimulated by cell surface cAMP receptors. The GTP produced by the action of NDP kinase is capable of activating G-proteins as monitored by altered G-protein-receptor interaction and the activation of the effector enzyme phospholipase C. Furthermore, specific monoclonal antibodies inhibit the effect of NDP kinase on G-protein activation. These results suggest that receptor-stimulated NDP kinase contributes to the mediation of hormone action by producing GTP for the activation of GTP-binding proteins. Images PMID:8389692

  3. Three-dimensional structure of a glycosylated cell surface antigen from D. discoideum: a primordial adhesion motif

    International Nuclear Information System (INIS)

    Mabbutt, B.C.; Swarbrick, J.; Cubeddu, L.; Hill, A.

    1999-01-01

    Full text: We have determined the solution structure of pre-spore specific antigen (PsA), a predominant cell surface glycoprotein from the slime mould Dictyostelium discoideum. The structure and function of this protein suggests that it serves as a molecular signal for multicellular organisation, and that it may also be an adhesion motif mediating direct cell-cell contact. PsA consists of a 90-residue N-terminal globular domain tethered to the cell membrane via a heavily O-glycosylated stalk and a GPI anchor. No homologous sequences have been identified for the N-terminal domain. At Macquarie University, the D. discoideum organism has been well developed as a eukaryotic expression host for glycosylated proteins. For NMR, we have engineered a soluble form of PsA (residues 1-122) containing the globular 'head' and the glycopeptide linker. 15 N- and 15 N/ 13 C-labelled PsA was generated in this organism via a protocol that is readily adaptable for the cost-effective production of milligram quantities of other isotopically labelled recombinant proteins. Using 3D heteronuclear NMR, we have solved the three-dimensional structure of the PsA glycoprotein. It defines an eight stranded β-sandwich of five-on-three topology in a unique arrangement. A long loop is constrained by a cis proline residue and a disulphide bond to form an opening across one end of the sandwich, exposing portions of the hydrophobic interior. We postulate that this distortion of the sandwich fold structures a binding site. Structural and dynamics information was also obtained concerning the intact glycopeptide linker of the protein, which comprises a repeating P-T-V-T motif. In our recombinant form, each Thr residue is modified by a single GlcNAc sugar. This simple structure yields interpretable NMR spectra, which show the glycosylated linker to be in extended conformation, and undergoing distinctly different mobility from the globular domain. These same sugar residues provide an ideal attachment

  4. Evidence for nucleolar subcompartments in Dictyostelium

    International Nuclear Information System (INIS)

    Catalano, Andrew; O’Day, Danton H.

    2015-01-01

    Highlights: • Two nucleolar subcompartments (NoSC1, NoSC2) were found in Dictyostelium. • Specific nucleolar proteins localize to different nucleolar subcompartments. • Specific proteins exit NoSC1 and NoSC2 differently upon Actinomycin D treatment. • KRKR appears to function as an NoSC2 nucleolar subcompartment localization signal. - Abstract: The nucleolus is a multifunctional nuclear compartment usually consisting of two to three subcompartments which represent stages of ribosomal biogenesis. It is linked to several human diseases including viral infections, cancer, and neurodegeneration. Dictyostelium is a model eukaryote for the study of fundamental biological processes as well as several human diseases however comparatively little is known about its nucleolus. Unlike most nucleoli it does not possess visible subcompartments at the ultrastructural level. Several recently identified nucleolar proteins in Dictyostelium leave the nucleolus after treatment with the rDNA transcription inhibitor actinomycin-D (AM-D). Different proteins exit in different ways, suggesting that previously unidentified nucleolar subcompartments may exist. The identification of nucleolar subcompartments would help to better understand the nucleolus in this model eukaryote. Here, we show that Dictyostelium nucleolar proteins nucleomorphin isoform NumA1 and Bud31 localize throughout the entire nucleolus while calcium-binding protein 4a localizes to only a portion, representing nucleolar subcompartment 1 (NoSC1). SWI/SNF complex member Snf12 localizes to a smaller area within NoSC1 representing a second nucleolar subcompartment, NoSC2. The nuclear/nucleolar localization signal KRKR from Snf12 localized GFP to NoSC2, and thus also appears to function as a nucleolar subcompartment localization signal. FhkA localizes to the nucleolar periphery displaying a similar pattern to that of Hsp32. Similarities between the redistribution patterns of Dictyostelium nucleolar proteins during

  5. Evidence for nucleolar subcompartments in Dictyostelium

    Energy Technology Data Exchange (ETDEWEB)

    Catalano, Andrew, E-mail: acatalano@ccny.cuny.edu [Department of Biology, University of Toronto at Mississauga, 3359 Mississauga Rd. N., Mississauga, Ontario L5L 1C6 (Canada); O’Day, Danton H., E-mail: danton.oday@utoronto.ca [Department of Biology, University of Toronto at Mississauga, 3359 Mississauga Rd. N., Mississauga, Ontario L5L 1C6 (Canada); Department of Cell and Systems Biology, University of Toronto, 25 Harbord St., Toronto, Ontario M5S 3G5 (Canada)

    2015-01-24

    Highlights: • Two nucleolar subcompartments (NoSC1, NoSC2) were found in Dictyostelium. • Specific nucleolar proteins localize to different nucleolar subcompartments. • Specific proteins exit NoSC1 and NoSC2 differently upon Actinomycin D treatment. • KRKR appears to function as an NoSC2 nucleolar subcompartment localization signal. - Abstract: The nucleolus is a multifunctional nuclear compartment usually consisting of two to three subcompartments which represent stages of ribosomal biogenesis. It is linked to several human diseases including viral infections, cancer, and neurodegeneration. Dictyostelium is a model eukaryote for the study of fundamental biological processes as well as several human diseases however comparatively little is known about its nucleolus. Unlike most nucleoli it does not possess visible subcompartments at the ultrastructural level. Several recently identified nucleolar proteins in Dictyostelium leave the nucleolus after treatment with the rDNA transcription inhibitor actinomycin-D (AM-D). Different proteins exit in different ways, suggesting that previously unidentified nucleolar subcompartments may exist. The identification of nucleolar subcompartments would help to better understand the nucleolus in this model eukaryote. Here, we show that Dictyostelium nucleolar proteins nucleomorphin isoform NumA1 and Bud31 localize throughout the entire nucleolus while calcium-binding protein 4a localizes to only a portion, representing nucleolar subcompartment 1 (NoSC1). SWI/SNF complex member Snf12 localizes to a smaller area within NoSC1 representing a second nucleolar subcompartment, NoSC2. The nuclear/nucleolar localization signal KRKR from Snf12 localized GFP to NoSC2, and thus also appears to function as a nucleolar subcompartment localization signal. FhkA localizes to the nucleolar periphery displaying a similar pattern to that of Hsp32. Similarities between the redistribution patterns of Dictyostelium nucleolar proteins during

  6. Journal of Biosciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    A model for cell type localization in the migrating slug of Dictyostelium discoideum based on differential ... a progressive maturation of chemotactic properties during the transdifferentiation of slug cell types. ... Journal of Biosciences | News ...

  7. Phg1/TM9 proteins control intracellular killing of bacteria by determining cellular levels of the Kil1 sulfotransferase in Dictyostelium.

    Directory of Open Access Journals (Sweden)

    Marion Le Coadic

    Full Text Available Dictyostelium discoideum has largely been used to study phagocytosis and intracellular killing of bacteria. Previous studies have shown that Phg1A, Kil1 and Kil2 proteins are necessary for efficient intracellular killing of Klebsiella bacteria. Here we show that in phg1a KO cells, cellular levels of lysosomal glycosidases and lysozyme are decreased, and lysosomal pH is increased. Surprisingly, overexpression of Kil1 restores efficient killing in phg1a KO cells without correcting these lysosomal anomalies. Conversely, kil1 KO cells are defective for killing, but their enzymatic content and lysosomal pH are indistinguishable from WT cells. The killing defect of phg1a KO cells can be accounted for by the observation that in these cells the stability and the cellular amount of Kil1 are markedly reduced. Since Kil1 is the only sulfotransferase characterized in Dictyostelium, an (unidentified sulfated factor, defective in both phg1a and kil1 KO cells, may play a key role in intracellular killing of Klebsiella bacteria. In addition, Phg1B plays a redundant role with Phg1A in controlling cellular amounts of Kil1 and intracellular killing. Finally, cellular levels of Kil1 are unaffected in kil2 KO cells, and Kil1 overexpression does not correct the killing defect of kil2 KO cells, suggesting that Kil2 plays a distinct role in intracellular killing.

  8. Derivatives of Dictyostelium differentiation-inducing factors inhibit lysophosphatidic acid–stimulated migration of murine osteosarcoma LM8 cells

    Energy Technology Data Exchange (ETDEWEB)

    Kubohara, Yuzuru, E-mail: ykuboha@juntendo.ac.jp [Department of Molecular and Cellular Biology, Institute for Molecular and Cellular Regulation (IMCR), Gunma University, Maebashi 371-8512 (Japan); Department of Health Science, Juntendo University Graduate School of Health and Sports Science, Inzai 270-1695 (Japan); Komachi, Mayumi [Department of Molecular and Cellular Biology, Institute for Molecular and Cellular Regulation (IMCR), Gunma University, Maebashi 371-8512 (Japan); Department of Radiation Oncology, Gunma University Graduate School of Medicine, Maebashi 371-8511 (Japan); Homma, Yoshimi [Department of Biomolecular Science, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine, Fukushima 960-1295 (Japan); Kikuchi, Haruhisa; Oshima, Yoshiteru [Laboratory of Natural Product Chemistry, Tohoku University Graduate School of Pharmaceutical Sciences, Aoba-yama, Aoba-ku, Sendai 980-8578 (Japan)

    2015-08-07

    Osteosarcoma is a common metastatic bone cancer that predominantly develops in children and adolescents. Metastatic osteosarcoma remains associated with a poor prognosis; therefore, more effective anti-metastatic drugs are needed. Differentiation-inducing factor-1 (DIF-1), −2, and −3 are novel lead anti-tumor agents that were originally isolated from the cellular slime mold Dictyostelium discoideum. Here we investigated the effects of a panel of DIF derivatives on lysophosphatidic acid (LPA)-induced migration of mouse osteosarcoma LM8 cells by using a Boyden chamber assay. Some DIF derivatives such as Br-DIF-1, DIF-3(+2), and Bu-DIF-3 (5–20 μM) dose-dependently suppressed LPA-induced cell migration with associated IC{sub 50} values of 5.5, 4.6, and 4.2 μM, respectively. On the other hand, the IC{sub 50} values of Br-DIF-1, DIF-3(+2), and Bu-DIF-3 versus cell proliferation were 18.5, 7.2, and 2.0 μM, respectively, in LM8 cells, and >20, 14.8, and 4.3 μM, respectively, in mouse 3T3-L1 fibroblasts (non-transformed). Together, our results demonstrate that Br-DIF-1 in particular may be a valuable tool for the analysis of cancer cell migration, and that DIF derivatives such as DIF-3(+2) and Bu-DIF-3 are promising lead anti-tumor agents for the development of therapies that suppress osteosarcoma cell proliferation, migration, and metastasis. - Highlights: • LPA induces cell migration (invasion) in murine osteosarcoma LM8 cells. • DIFs are novel lead anti-tumor agents found in Dictyostelium discoideum. • We examined the effects of DIF derivatives on LPA-induced LM8 cell migration in vitro. • Some of the DIF derivatives inhibited LPA-induced LM8 cell migration.

  9. Loss of Cln3 impacts protein secretion in the social amoeba Dictyostelium.

    Science.gov (United States)

    Huber, Robert J

    2017-07-01

    Neuronal ceroid lipofuscinosis (NCL), also referred to as Batten disease, is the most common form of childhood neurodegeneration. Mutations in CLN3 cause the most prevalent subtype of the disease, which manifests during early childhood and is currently untreatable. The precise function of the CLN3 protein is still not known, which has inhibited the development of targeted therapies. In the social amoeba Dictyostelium discoideum, loss of the CLN3 homolog, Cln3, reduces adhesion during early development, which delays streaming and aggregation. The results of the present study indicate that this phenotype may be at least partly due to aberrant protein secretion in cln3 - cells. It is well-established that Cln3 localizes primarily to the contractile vacuole (CV) system in Dictyostelium, and to a lesser extent, compartments of the endocytic pathway. Intriguingly, the CV system has been linked to the secretion of proteins that do not contain a signal peptide for secretion (i.e., unconventional protein secretion). Proteins that do contain a signal peptide are secreted via a conventional mechanism involving the endoplasmic reticulum, transport through the Golgi, and secretion via vesicle release. In this study, Cln3 was observed to co-localize with the Golgi marker wheat germ agglutinin suggesting that Cln3 participates in both secretion mechanisms. Chimeras of wild-type (WT) and cln3 - cells displayed delayed streaming and aggregation, and interestingly, cln3 - cells starved in conditioned media (CM) harvested from starving WT cells showed near normal timing of streaming and aggregation suggesting aberrant protein secretion in Cln3-deficient cells. Based on these observations, LC-MS/MS was used to reveal the protein content of CM from starved cells (mass spectrometry data are available via ProteomeXchange with identifier PXD004897). A total of 450 proteins were detected in WT and cln3 - CM, of which 3 were absent in cln3 - CM. Moreover, 12 proteins that were present in

  10. Dispatch. Dictyostelium chemotaxis: fascism through the back door?

    Science.gov (United States)

    Insall, Robert

    2003-04-29

    Aggregating Dictyostelium cells secrete cyclic AMP to attract their neighbours by chemotaxis. It has now been shown that adenylyl cyclase is enriched in the rear of cells, and this localisation is required for normal aggregation.

  11. A Simple Retroelement Based Knock-Down System in Dictyostelium: Further Insights into RNA Interference Mechanisms.

    Science.gov (United States)

    Friedrich, Michael; Meier, Doreen; Schuster, Isabelle; Nellen, Wolfgang

    2015-01-01

    We have previously shown that the most abundant Dictyostelium discoideum retroelement DIRS-1 is suppressed by RNAi mechanisms. Here we provide evidence that both inverted terminal repeats have strong promoter activity and that bidirectional expression apparently generates a substrate for Dicer. A cassette containing the inverted terminal repeats and a fragment of a gene of interest was sufficient to activate the RNAi response, resulting in the generation of ~21 nt siRNAs, a reduction of mRNA and protein expression of the respective endogene. Surprisingly, no transitivity was observed on the endogene. This was in contrast to previous observations, where endogenous siRNAs caused spreading on an artificial transgene. Knock-down was successful on seven target genes that we examined. In three cases a phenotypic analysis proved the efficiency of the approach. One of the target genes was apparently essential because no knock-out could be obtained; the RNAi mediated knock-down, however, resulted in a very slow growing culture indicating a still viable reduction of gene expression. ADVANTAGES OF THE DIRS-1–RNAI SYSTEM: The knock-down system required a short DNA fragment (~400 bp) of the target gene as an initial trigger. Further siRNAs were generated by RdRPs since we have shown some siRNAs with a 5'-triphosphate group. Extrachromosomal vectors facilitate the procedure and allowed for molecular and phenotypic analysis within one week. The system provides an efficient and rapid method to reduce protein levels including those of essential genes.

  12. TRE5-A retrotransposition profiling reveals putative RNA polymerase III transcription complex binding sites on the Dictyostelium extrachromosomal rDNA element.

    Directory of Open Access Journals (Sweden)

    Thomas Spaller

    Full Text Available The amoeba Dictyostelium discoideum has a haploid genome in which two thirds of the DNA encodes proteins. Consequently, the space available for selfish mobile elements to expand without excess damage to the host genome is limited. The non-long terminal repeat retrotransposon TRE5-A maintains an active population in the D. discoideum genome and apparently adapted to this gene-dense environment by targeting positions ~47 bp upstream of tRNA genes that are devoid of protein-coding regions. Because only ~24% of tRNA genes are associated with a TRE5-A element in the reference genome, we evaluated whether TRE5-A retrotransposition is limited to this subset of tRNA genes. We determined that a tagged TRE5-A element (TRE5-Absr integrated at 384 of 405 tRNA genes, suggesting that expansion of the current natural TRE5-A population is not limited by the availability of targets. We further observed that TRE5-Absr targets the ribosomal 5S gene on the multicopy extrachromosomal DNA element that carries the ribosomal RNA genes, indicating that TRE5-A integration may extend to the entire RNA polymerase III (Pol III transcriptome. We determined that both natural TRE5-A and cloned TRE5-Absr retrotranspose to locations on the extrachromosomal rDNA element that contain tRNA gene-typical A/B box promoter motifs without displaying any other tRNA gene context. Based on previous data suggesting that TRE5-A targets tRNA genes by locating Pol III transcription complexes, we propose that A/B box loci reflect Pol III transcription complex assembly sites that possess a function in the biology of the extrachromosomal rDNA element.

  13. An evolutionarily significant unicellular strategy in response to starvation stress in Dictyostelium social amoebae [v1; ref status: indexed, http://f1000r.es/3hg

    Directory of Open Access Journals (Sweden)

    Darja Dubravcic

    2014-06-01

    Full Text Available The social amoeba Dictyostelium discoideum is widely studied for its multicellular development program as a response to starvation and constitutes a model of choice in microbial cooperation studies. Aggregates of up to 106 cells form fruiting bodies containing two cell types: (i dormant spores (~80% that can persist for months in the absence of nutrients, and (ii dead stalk cells (~20% that promote the dispersion of the spores towards nutrient-rich areas. It is often overlooked that not all cells aggregate upon starvation. Using a new quantitative approach based on time-lapse fluorescence microscopy and a low ratio of reporting cells, we have quantified this fraction of non-aggregating cells. In realistic starvation conditions, up to 15% of cells do not aggregate, which makes this third cell fate a significant component of the population-level response of social amoebae to starvation. Non-aggregating cells have an advantage over cells in aggregates since they resume growth earlier upon arrival of new nutrients, but have a shorter lifespan under prolonged starvation. We find that phenotypic heterogeneities linked to cell nutritional state bias the representation of cells in the aggregating vs. non-aggregating fractions, and thus regulate population partitioning. Next, we report that the fraction of non-aggregating cells depends on genetic factors that regulate the timing of starvation, signal sensing efficiency and aggregation efficiency. In addition, interactions between clones in mixtures of non-isogenic cells affect the partitioning of each clone into both fractions. We further test the evolutionary significance of the non-aggregating cell fraction. The partitioning of cells into aggregating and non-aggregating fractions is optimal in fluctuating environments with an unpredictable duration of starvation periods. D. discoideum thus constitutes a model system lying at the intersection of microbial cooperation and bet hedging, defining a new

  14. Biochemistry and genetics of inositol phosphate metabolism in Dictyostelium

    NARCIS (Netherlands)

    vanHaastert, PJM; van Dijken, P.

    1997-01-01

    Biochemical and genetic data on the metabolism of inositol phosphates in the microorganism Dictyostelium are combined in a scheme composed of in five subroutes. The first subroute is the inositol cycle as found in other organisms:inositol is incorporated into phospholipids that are hydrolysed by PLC

  15. Characterization of two unusual guanylyl cyclases from Dictyostelium

    NARCIS (Netherlands)

    Roelofs, Jeroen; Haastert, Peter J.M. van

    2002-01-01

    Guanylyl cyclase A (GCA) and soluble guanylyl cyclase (sGC) encode GCs in Dictyostelium and have a topology similar to 12-transmembrane and soluble adenylyl cyclase, respectively. We demonstrate that all detectable GC activity is lost in a cell line in which both genes have been inactivated. Cell

  16. Involvement of Sib Proteins in the Regulation of Cellular Adhesion in Dictyostelium discoideum▿ †

    OpenAIRE

    Cornillon, Sophie; Froquet, Romain; Cosson, Pierre

    2008-01-01

    Molecular mechanisms ensuring cellular adhesion have been studied in detail in Dictyostelium amoebae, but little is known about the regulation of cellular adhesion in these cells. Here, we show that cellular adhesion is regulated in Dictyostelium, notably by the concentration of a cellular secreted factor accumulating in the medium. This constitutes a quorum-sensing mechanism allowing coordinated regulation of cellular adhesion in a Dictyostelium population. In order to understand the mechani...

  17. The putative bZIP transcription factor BzpN slows proliferation and functions in the regulation of cell density by autocrine signals in Dictyostelium.

    Directory of Open Access Journals (Sweden)

    Jonathan E Phillips

    Full Text Available The secreted proteins AprA and CfaD function as autocrine signals that inhibit cell proliferation in Dictyostelium discoideum, thereby regulating cell numbers by a negative feedback mechanism. We report here that the putative basic leucine zipper transcription factor BzpN plays a role in the inhibition of proliferation by AprA and CfaD. Cells lacking BzpN proliferate more rapidly than wild-type cells but do not reach a higher stationary density. Recombinant AprA inhibits wild-type cell proliferation but does not inhibit the proliferation of cells lacking BzpN. Recombinant CfaD also inhibits wild-type cell proliferation, but promotes the proliferation of cells lacking BzpN. Overexpression of BzpN results in a reduced cell density at stationary phase, and this phenotype requires AprA, CfaD, and the kinase QkgA. Conditioned media from high-density cells stops the proliferation of wild-type but not bzpN(- cells and induces a nuclear localization of a BzpN-GFP fusion protein, though this localization does not require AprA or CfaD. Together, the data suggest that BzpN is necessary for some but not all of the effects of AprA and CfaD, and that BzpN may function downstream of AprA and CfaD in a signal transduction pathway that inhibits proliferation.

  18. The Putative bZIP Transcripton Factor BzpN Slows Proliferation and Functions in the Regulation of Cell Density by Autocrine Signals in Dictyostelium

    Science.gov (United States)

    Phillips, Jonathan E.; Huang, Eryong; Shaulsky, Gad; Gomer, Richard H.

    2011-01-01

    The secreted proteins AprA and CfaD function as autocrine signals that inhibit cell proliferation in Dictyostelium discoideum, thereby regulating cell numbers by a negative feedback mechanism. We report here that the putative basic leucine zipper transcription factor BzpN plays a role in the inhibition of proliferation by AprA and CfaD. Cells lacking BzpN proliferate more rapidly than wild-type cells but do not reach a higher stationary density. Recombinant AprA inhibits wild-type cell proliferation but does not inhibit the proliferation of cells lacking BzpN. Recombinant CfaD also inhibits wild-type cell proliferation, but promotes the proliferation of cells lacking BzpN. Overexpression of BzpN results in a reduced cell density at stationary phase, and this phenotype requires AprA, CfaD, and the kinase QkgA. Conditioned media from high-density cells stops the proliferation of wild-type but not bzpN− cells and induces a nuclear localization of a BzpN-GFP fusion protein, though this localization does not require AprA or CfaD. Together, the data suggest that BzpN is necessary for some but not all of the effects of AprA and CfaD, and that BzpN may function downstream of AprA and CfaD in a signal transduction pathway that inhibits proliferation. PMID:21760904

  19. The putative bZIP transcription factor BzpN slows proliferation and functions in the regulation of cell density by autocrine signals in Dictyostelium.

    Science.gov (United States)

    Phillips, Jonathan E; Huang, Eryong; Shaulsky, Gad; Gomer, Richard H

    2011-01-01

    The secreted proteins AprA and CfaD function as autocrine signals that inhibit cell proliferation in Dictyostelium discoideum, thereby regulating cell numbers by a negative feedback mechanism. We report here that the putative basic leucine zipper transcription factor BzpN plays a role in the inhibition of proliferation by AprA and CfaD. Cells lacking BzpN proliferate more rapidly than wild-type cells but do not reach a higher stationary density. Recombinant AprA inhibits wild-type cell proliferation but does not inhibit the proliferation of cells lacking BzpN. Recombinant CfaD also inhibits wild-type cell proliferation, but promotes the proliferation of cells lacking BzpN. Overexpression of BzpN results in a reduced cell density at stationary phase, and this phenotype requires AprA, CfaD, and the kinase QkgA. Conditioned media from high-density cells stops the proliferation of wild-type but not bzpN(-) cells and induces a nuclear localization of a BzpN-GFP fusion protein, though this localization does not require AprA or CfaD. Together, the data suggest that BzpN is necessary for some but not all of the effects of AprA and CfaD, and that BzpN may function downstream of AprA and CfaD in a signal transduction pathway that inhibits proliferation.

  20. A retinoblastoma orthologue is a major regulator of S-phase, mitotic, and developmental gene expression in Dictyostelium.

    Directory of Open Access Journals (Sweden)

    Kimchi Strasser

    Full Text Available The retinoblastoma tumour suppressor, Rb, has two major functions. First, it represses genes whose products are required for S-phase entry and progression thus stabilizing cells in G1. Second, Rb interacts with factors that induce cell-cycle exit and terminal differentiation. Dictyostelium lacks a G1 phase in its cell cycle but it has a retinoblastoma orthologue, rblA.Using microarray analysis and mRNA-Seq transcriptional profiling, we show that RblA strongly represses genes whose products are involved in S phase and mitosis. Both S-phase and mitotic genes are upregulated at a single point in late G2 and again in mid-development, near the time when cell cycling is reactivated. RblA also activates a set of genes unique to slime moulds that function in terminal differentiation.Like its mammalian counterpart Dictyostelium, RblA plays a dual role, regulating cell-cycle progression and transcriptional events leading to terminal differentiation. In the absence of a G1 phase, however, RblA functions in late G2 controlling the expression of both S-phase and mitotic genes.

  1. A secreted factor represses cell proliferation in Dictyostelium

    OpenAIRE

    Brock, Debra A.; Gomer, Richard H.

    2005-01-01

    Many cells appear to secrete factors called chalones that limit their proliferation, but in most cases the factors have not been identified. We found that growing Dictyostelium cells secrete a 60 kDa protein called AprA for autocrine proliferation repressor. AprA has similarity to putative bacterial proteins of unknown function. Compared with wild-type cells, aprA-null cells proliferate faster, while AprA overexpressing cells proliferate slower. Growing wild-type cells secrete a factor that i...

  2. External stimulation strength controls actin response dynamics in Dictyostelium cells

    Science.gov (United States)

    Hsu, Hsin-Fang; Westendorf, Christian; Tarantola, Marco; Zykov, Vladimir; Bodenschatz, Eberhard; Beta, Carsten

    2015-03-01

    Self-sustained oscillation and the resonance frequency of the cytoskeletal actin polymerization/depolymerization have recently been observed in Dictyostelium, a model system for studying chemotaxis. Here we report that the resonance frequency is not constant but rather varies with the strength of external stimuli. To understand the underlying mechanism, we analyzed the polymerization and depolymerization time at different levels of external stimulation. We found that polymerization time is independent of external stimuli but the depolymerization time is prolonged as the stimulation increases. These observations can be successfully reproduced in the frame work of our time delayed differential equation model.

  3. Dicty_cDB: CFC194 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available equences producing significant alignments: (bits) Value N AF305060 |AF305060.1 Dictyostelium discoideum Wiscott...nts: (bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott

  4. Dicty_cDB: AFE360 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available t alignments: (bits) Value N AF305060 |AF305060.1 Dictyostelium discoideum Wiscott-Aldrich syndrome protein ...(bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott-A..

  5. Dicty_cDB: AFF743 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available Sequences producing significant alignments: (bits) Value N AF305060 |AF305060.1 Dictyostelium discoideum Wiscott...oducing significant alignments: (bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott

  6. Dicty_cDB: AFG687 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ant alignments: (bits) Value N AF305060 |AF305060.1 Dictyostelium discoideum Wiscott...n Score E Sequences producing significant alignments: (bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott

  7. Dicty_cDB: SFC807 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available icant alignments: (bits) Value N AF305060 |AF305060.1 Dictyostelium discoideum Wiscott-Aldrich syndrome prot...ng significant alignments: (bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott

  8. A secreted factor represses cell proliferation in Dictyostelium.

    Science.gov (United States)

    Brock, Debra A; Gomer, Richard H

    2005-10-01

    Many cells appear to secrete factors called chalones that limit their proliferation, but in most cases the factors have not been identified. We found that growing Dictyostelium cells secrete a 60 kDa protein called AprA for autocrine proliferation repressor. AprA has similarity to putative bacterial proteins of unknown function. Compared with wild-type cells, aprA-null cells proliferate faster, while AprA overexpressing cells proliferate slower. Growing wild-type cells secrete a factor that inhibits the proliferation of wild-type and aprA- cells; this activity is not secreted by aprA- cells. AprA purified by immunoprecipitation also slows the proliferation of wild-type and aprA- cells. Compared with wild type, there is a higher percentage of multinucleate cells in the aprA- population, and when starved, aprA- cells form abnormal structures that contain fewer spores. AprA may thus decrease the number of multinucleate cells and increase spore production. Together, the data suggest that AprA functions as part of a Dictyostelium chalone.

  9. Differential Role of Poly(ADP-ribose polymerase in D. discoideum growth and development

    Directory of Open Access Journals (Sweden)

    Begum Rasheedunnisa

    2011-03-01

    Full Text Available Abstract Background Poly(ADP-ribose polymerase is evolutionarily conserved as a responder to various forms of stress. Though PARP's role in cell death is well addressed, its role in development and multicellularity is still an enigma. We have previously reported the role of PARP in oxidative stress induced delayed development of D. discoideum. Results In the current study we highlight the involvement of PARP during D. discoideum development. Oxidative stress affects expression of aca and cAR1 thus affecting aggregation. Although parp expression is not affected during oxidative stress but it is involved during normal development as confirmed by our PARP down-regulation studies. Constitutive PARP down-regulation resulted in blocked development while no effect was observed on D. discoideum growth. Interestingly, stage specific PARP down-regulation arrested development at the slug stage. Conclusion These results emphasize that PARP is essential for complex differentiation and its function may be linked to multicellularity. This is the first report where the involvement of PARP during normal multicellular development in D. discoideum, an ancient eukaryote, is established which could be of evolutionary significance. Thus our study adds one more role to the multitasking function of PARP.

  10. Dicty_cDB: Contig-U13443-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available lignments: (bits) Value N ( AF305060 ) Dictyostelium discoideum Wiscott-Aldrich syndrome... 529 0.0 10 ( BJ3... AF305060 ) Dictyostelium discoideum Wiscott-Aldrich syndrome protein (wasA) gene...icant alignments: (bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott...0_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott-Aldrich syndrome protein (wasA) gene, complete cds

  11. Mechano-chemical signaling maintains the rapid movement of Dictyostelium cells

    International Nuclear Information System (INIS)

    Lombardi, M.L.; Knecht, D.A.; Lee, J.

    2008-01-01

    The survival of Dictyostelium cells depends on their ability to efficiently chemotax, either towards food or to form multicellular aggregates. Although the involvement of Ca 2+ signaling during chemotaxis is well known, it is not clear how this regulates cell movement. Previously, fish epithelial keratocytes have been shown to display transient increases in intracellular calcium ([Ca 2+ ] i ) that are mediated by stretch-activated calcium channels (SACs), which play a role in retraction of the cell body [J. Lee, A. Ishihara, G. Oxford, B. Johnson, and K. Jacobson, Regulation of cell movement is mediated by stretch-activated calcium channels. Nature, 1999. 400(6742): p. 382-6.]. To investigate the involvement of SACs in Dictyostelium movement we performed high resolution calcium imaging in wild-type (NC4A2) Dictyostelium cells to detect changes in [Ca 2+ ] i . We observed small, brief, Ca 2+ transients in randomly moving wild-type cells that were dependent on both intracellular and extracellular sources of calcium. Treatment of cells with the SAC blocker gadolinium (Gd 3+ ) inhibited transients and decreased cell speed, consistent with the involvement of SACs in regulating Dictyostelium motility. Additional support for SAC activity was given by the increase in frequency of Ca 2+ transients when Dictyostelium cells were moving on a more adhesive substratum or when they were mechanically stretched. We conclude that mechano-chemical signaling via SACs plays a major role in maintaining the rapid movement of Dictyostelium cells

  12. NCBI nr-aa BLAST: CBRC-DDIS-01-0132 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-DDIS-01-0132 ref|XP_646256.1| cellulose synthase [Dictyostelium discoideum AX4...] gb|AAF00200.1|AF163835_1 cellulose synthase [Dictyostelium discoideum] gb|EAL71912.1| cellulose synthase [Dictyostelium discoideum AX4] XP_646256.1 0.0 99% ...

  13. NCBI nr-aa BLAST: CBRC-DDIS-01-0111 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-DDIS-01-0111 ref|XP_636760.1| alkaline dihydroceramidase [Dictyostelium discoi...deum AX4] gb|AAQ98884.1| alkaline dihydroceramidase [Dictyostelium discoideum] gb|EAL63276.1| alkaline dihydroceramidase [Dictyostelium discoideum AX4] XP_636760.1 7e-59 45% ...

  14. Heteromeric p97/p97R155C complexes induce dominant negative changes in wild-type and autophagy 9-deficient Dictyostelium strains.

    Directory of Open Access Journals (Sweden)

    Khalid Arhzaouy

    Full Text Available Heterozygous mutations in the human VCP (p97 gene cause autosomal-dominant IBMPFD (inclusion body myopathy with early onset Paget's disease of bone and frontotemporal dementia, ALS14 (amyotrophic lateral sclerosis with or without frontotemporal dementia and HSP (hereditary spastic paraplegia. Most prevalent is the R155C point mutation. We studied the function of p97 in the social amoeba Dictyostelium discoideum and have generated strains that ectopically express wild-type (p97 or mutant p97 (p97(R155C fused to RFP in AX2 wild-type and autophagy 9 knock-out (ATG9(KO cells. Native gel electrophoresis showed that both p97 and p97(R155C assemble into hexamers. Co-immunoprecipitation studies revealed that endogenous p97 and p97(R155C-RFP form heteromers. The mutant strains displayed changes in cell growth, phototaxis, development, proteasomal activity, ubiquitinylated proteins, and ATG8(LC3 indicating mis-regulation of multiple essential cellular processes. Additionally, immunofluorescence analysis revealed an increase of protein aggregates in ATG9(KO/p97(R155C-RFP and ATG9(KO cells. They were positive for ubiquitin in both strains, however, solely immunoreactive for p97 in the ATG9(KO mutant. A major finding is that the expression of p97(R155C-RFP in the ATG9(KO strain partially or fully rescued the pleiotropic phenotype. We also observed dose-dependent effects of p97 on several cellular processes. Based on findings in the single versus the double mutants we propose a novel mode of p97 interaction with the core autophagy protein ATG9 which is based on mutual inhibition.

  15. A Dictyostelium chalone uses G proteins to regulate proliferation

    Directory of Open Access Journals (Sweden)

    Hanson Nana E

    2009-07-01

    Full Text Available Abstract Background Several studies have shown that organ size, and the proliferation of tumor metastases, may be regulated by negative feedback loops in which autocrine secreted factors called chalones inhibit proliferation. However, very little is known about chalones, and how cells sense them. We previously identified two secreted proteins, AprA and CfaD, which act as chalones in Dictyostelium. Cells lacking AprA or CfaD proliferate faster than wild-type cells, and adding recombinant AprA or CfaD to cells slows their proliferation. Results We show here that cells lacking the G protein components Galpha8, Galpha9, and Gbeta proliferate faster than wild-type cells despite secreting normal or high levels of AprA and CfaD. Compared with wild-type cells, the proliferation of galpha8-, galpha9- and gbeta- cells are only weakly inhibited by recombinant AprA (rAprA. Like AprA and CfaD, Galpha8 and Gbeta inhibit cell proliferation but not cell growth (the rate of increase in mass and protein per nucleus, whereas Galpha9 inhibits both proliferation and growth. galpha8- cells show normal cell-surface binding of rAprA, whereas galpha9- and gbeta- cells have fewer cell-surface rAprA binding sites, suggesting that Galpha9 and Gbeta regulate the synthesis or processing of the AprA receptor. Like other ligands that activate G proteins, rAprA induces the binding of [3H]GTP to membranes, and GTPgammaS inhibits the binding of rAprA to membranes. Both AprA-induced [3H]GTP binding and the GTPgammaS inhibition of rAprA binding require Galpha8 and Gbeta but not Galpha9. Like aprA- cells, galpha8- cells have reduced spore viability. Conclusion This study shows that Galpha8 and Gbeta are part of the signal transduction pathway used by AprA to inhibit proliferation but not growth in Dictyostelium, whereas Galpha9 is part of a differealnt pathway that regulates both proliferation and growth, and that a chalone signal transduction pathway uses G proteins.

  16. A Dictyostelium chalone uses G proteins to regulate proliferation.

    Science.gov (United States)

    Bakthavatsalam, Deenadayalan; Choe, Jonathan M; Hanson, Nana E; Gomer, Richard H

    2009-07-27

    Several studies have shown that organ size, and the proliferation of tumor metastases, may be regulated by negative feedback loops in which autocrine secreted factors called chalones inhibit proliferation. However, very little is known about chalones, and how cells sense them. We previously identified two secreted proteins, AprA and CfaD, which act as chalones in Dictyostelium. Cells lacking AprA or CfaD proliferate faster than wild-type cells, and adding recombinant AprA or CfaD to cells slows their proliferation. We show here that cells lacking the G protein components Galpha8, Galpha9, and Gbeta proliferate faster than wild-type cells despite secreting normal or high levels of AprA and CfaD. Compared with wild-type cells, the proliferation of galpha8-, galpha9- and gbeta- cells are only weakly inhibited by recombinant AprA (rAprA). Like AprA and CfaD, Galpha8 and Gbeta inhibit cell proliferation but not cell growth (the rate of increase in mass and protein per nucleus), whereas Galpha9 inhibits both proliferation and growth. galpha8- cells show normal cell-surface binding of rAprA, whereas galpha9- and gbeta- cells have fewer cell-surface rAprA binding sites, suggesting that Galpha9 and Gbeta regulate the synthesis or processing of the AprA receptor. Like other ligands that activate G proteins, rAprA induces the binding of [3H]GTP to membranes, and GTPgammaS inhibits the binding of rAprA to membranes. Both AprA-induced [3H]GTP binding and the GTPgammaS inhibition of rAprA binding require Galpha8 and Gbeta but not Galpha9. Like aprA- cells, galpha8- cells have reduced spore viability. This study shows that Galpha8 and Gbeta are part of the signal transduction pathway used by AprA to inhibit proliferation but not growth in Dictyostelium, whereas Galpha9 is part of a differealnt pathway that regulates both proliferation and growth, and that a chalone signal transduction pathway uses G proteins.

  17. Mechanism of cAMP-induced H -efflux of Dictyostelium cells: a role ...

    Indian Academy of Sciences (India)

    Unknown

    2.1 Culture conditions and induction of the development of D. discoideum. Strain Ax-2 was grown ..... the H+-entry pathway for passive leakage of protons. Thus, the formation of any .... Universal Academy Press) pp 3–13. Maeda Y, Inouye K ...

  18. Ras proteins have multiple functions in vegetative cells of Dictyostelium.

    Science.gov (United States)

    Bolourani, Parvin; Spiegelman, George; Weeks, Gerald

    2010-11-01

    During the aggregation of Dictyostelium cells, signaling through RasG is more important in regulating cyclic AMP (cAMP) chemotaxis, whereas signaling through RasC is more important in regulating the cAMP relay. However, RasC is capable of substituting for RasG for chemotaxis, since rasG⁻ cells are only partially deficient in chemotaxis, whereas rasC⁻/rasG⁻ cells are totally incapable of chemotaxis. In this study we have examined the possible functional overlap between RasG and RasC in vegetative cells by comparing the vegetative cell properties of rasG⁻, rasC⁻, and rasC⁻/rasG⁻ cells. In addition, since RasD, a protein not normally found in vegetative cells, is expressed in vegetative rasG⁻ and rasC⁻/rasG⁻ cells and appears to partially compensate for the absence of RasG, we have also examined the possible functional overlap between RasG and RasD by comparing the properties of rasG⁻ and rasC⁻/rasG⁻ cells with those of the mutant cells expressing higher levels of RasD. The results of these two lines of investigation show that RasD is capable of totally substituting for RasG for cytokinesis and growth in suspension, whereas RasC is without effect. In contrast, for chemotaxis to folate, RasC is capable of partially substituting for RasG, but RasD is totally without effect. Finally, neither RasC nor RasD is able to substitute for the role that RasG plays in regulating actin distribution and random motility. These specificity studies therefore delineate three distinct and none-overlapping functions for RasG in vegetative cells.

  19. Overexpression of the cAMP Receptor 1 in Growing Dictyostelium Cells

    NARCIS (Netherlands)

    Johnson, Ronald L.; Vaughan, Roxanne A.; Caterina, Michael J.; Haastert, Peter J.M. van; Devreotes, Peter N.

    1991-01-01

    cAR1, the cAMP receptor expressed normally during the early aggregation stage of the Dictyostelium developmental program, has been expressed during the growth stage, when only low amounts of endogenous receptors are present. Transformants expressing cAR1 have 7-40 times over growth stage and

  20. Sensitization of Dictyostelium chemotaxis by phosphoinositide-3-kinase-mediated self-organizing signalling patches

    NARCIS (Netherlands)

    Postma, M.; Roelofs, J.; Goedhart, J.; Loovers, H.M.; Visser, A.J.W.G.; Haastert, van P.J.M.

    2004-01-01

    The leading edge of Dictyostelium cells in chemoattractant gradients can be visualized using green fluorescent protein (GFP) tagged to the pleckstrin-homology (PH) domain of cytosolic regulator of adenylyl cyclase (CRAC), which presumable binds phosphatidylinositol-(3,4,5)triphosphate

  1. Sensitization of Dictyostelium chemotaxis by phosphoinositide-3-kinase-mediated self-organizing signalling patches.

    NARCIS (Netherlands)

    Postma, M.; Roelofs, J.; Goedhart, J.; Loovers, H.M.; Visser, A.J.; van Haastert, P.J.

    2004-01-01

    The leading edge of Dictyostelium cells in chemoattractant gradients can be visualized using green fluorescent protein (GFP) tagged to the pleckstrin-homology (PH) domain of cytosolic regulator of adenylyl cyclase (CRAC), which presumable binds phosphatidylinositol-(3,4,5)triphosphate

  2. Multiple Degradation Pathways of Chemoattractant Mediated Cyclic GMP Accumulation in Dictyostelium

    NARCIS (Netherlands)

    Haastert, Peter J.M. van; Lookeren Campagne, Michiel M. van; Kesbeke, Fanja

    1983-01-01

    Chemoattractants induce a transient accumulation of cGMP levels in Dictyostelium. Intracellular cGMP levels reach a peak at 10 s and prestimulated cGMP levels are recovered at about 30 s. Intracellular and extracellular cGMP levels were detected simultaneously after stimulation of D. lacteum cells

  3. Pleckstrin Homology Domain Diffusion in Dictyostelium Cytoplasm Studied Using Fluorescence Correlation Spectroscopy

    NARCIS (Netherlands)

    Engel, Ruchira; Hink, Mark A.; Bosgraaf, Leonard; Haastert, Peter J.M. van; Visser, Antonie J.W.G.

    2004-01-01

    The translocation of pleckstrin homology (PH) domain-containing proteins from the cytoplasm to the plasma membrane plays an important role in the chemotaxis mechanism of Dictyostelium cells. The diffusion of three PH domain-green fluorescent protein (GFP) fusions (PH2-GFP, PH10-GFP, and PH-CRAC

  4. Pleckstrin homology domain diffusion in Dictyostelium cytoplasm studied using fluorescence correlation spectroscopy

    NARCIS (Netherlands)

    Ruchira, A.; Hink, M.A.; Bosgraaf, L.; Haastert, van P.J.M.; Visser, A.J.W.G.

    2004-01-01

    The translocation of pleckstrin homology (PH) domain-containing proteins from the cytoplasm to the plasma membrane plays an important role in the chemotaxis mechanism of Dictyostelium cells. The diffusion of three PH domain-green fluorescent protein (GFP) fusions (PH2-GFP, PH10-GFP, and PH-CRAC

  5. Dicty_cDB: SFF823 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available gy vs DNA Score E Sequences producing significant alignments: (bits) Value N AF305060 |AF305060.1 Dictyostelium discoideum Wiscott...id:none) Dictyostelium discoideum Wiscott-A... 83 3e-15 AC117076_18( AC117076 |pid:none) Dictyostelium disco

  6. Dicty_cDB: VFD730 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available omology vs DNA Score E Sequences producing significant alignments: (bits) Value N AF305060 |AF305060.1 Dictyostelium discoideum Wisco...otein Score E Sequences producing significant alignments: (bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wisco...tt-Aldrich syndrome protein (wasA) gene, complete cds. 4...tt-A... 83 3e-15 AC117076_18( AC117076 |pid:none) Dictyostelium discoideum chromoso

  7. Highlighting the role of Ras and Rap during Dictyostelium chemotaxis

    NARCIS (Netherlands)

    Kortholt, Arjan; van Haastert, Peter J. M.

    Chemotaxis, the directional movement towards a chemical compound, is an essential property of many cells and has been linked to the development and progression of many diseases. Eukaryotic chemotaxis is a complex process involving gradient sensing, cell polarity, remodelling of the cytoskeleton and

  8. Dictyostelium cells bind a secreted autocrine factor that represses cell proliferation

    OpenAIRE

    Choe, Jonathan M; Bakthavatsalam, Deenadayalan; Phillips, Jonathan E; Gomer, Richard H

    2009-01-01

    Abstract Background Dictyostelium cells secrete the proteins AprA and CfaD. Cells lacking either AprA or CfaD proliferate faster than wild type, while AprA or CfaD overexpressor cells proliferate slowly, indicating that AprA and CfaD are autocrine factors that repress proliferation. CfaD interacts with AprA and requires the presence of AprA to slow proliferation. To determine if CfaD is necessary for the ability of AprA to slow proliferation, whether AprA binds to cells, and if so whether the...

  9. Dicty_cDB: VHJ195 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available -B/AFN547Q.Seq.d/ 1342 0.0 SLE172 (SLE172Q) /CSM/SL/SLE1-C/SLE172Q.Seq.d/ 1102 0.0 SLD492 (SLD492Q) /CSM/SL/SLD4-D/SLD492...8502 ) Dictyostelium discoideum cDNA clone:dda28m11, 5' ... 839 0.0 2 ( AU052538 ) Dictyostelium discoideum slug cDNA, clone SLD492...2597 ) Dictyostelium discoideum slug cDNA, clone SLD569. 113 2e-20 1 ( AU061182 ) Dictyostelium discoideum slug cDNA, clone SLD492

  10. Cyclic AMP signalling in Dictyostelium : G-proteins activate separate Ras pathways using specific RasGEFs

    NARCIS (Netherlands)

    Kae, Helmut; Kortholt, Arjan; Rehmann, Holger; Insall, RobertH.; Van Haastert, Peter J. M.; Spiegelman, George B.; Weeks, Gerald

    In general, mammalian Ras guanine nucleotide exchange factors (RasGEFs) show little substrate specificity, although they are often thought to regulate specific pathways. Here, we provide in vitro and in vivo evidence that two RasGEFs can each act on specific Ras proteins. During Dictyostelium

  11. Nucleus-associated phosphorylation of Ins(1,4,5)P3 to InsP6 in Dictyostelium

    NARCIS (Netherlands)

    Kaay, Jeroen van der; Wesseling, Jelle; Haastert, Peter J.M. van

    1995-01-01

    Although many cells contain large amounts of InsP(6), its metabolism and function is still largely unknown. In Dictyostelium lysates, the formation of InsP(6) by sequential phosphorylation of inositol via Ins(3,4,6)P-3 has been described [Stevens and Irvine (1990) Nature (London) 346, 580-583]; the

  12. The role of cGMP and the rear of the cell in Dictyostelium chemotaxis and cell streaming

    NARCIS (Netherlands)

    Veltman, Douwe M.; van Haastert, Peter J. M.

    2008-01-01

    During chemotaxis, pseudopod extensions lead the cell towards the source of attractant. The role of actin-filled pseudopodia at the front of the cell is well recognized, whereas the function of the rear of the cell in chemotaxis and cell-cell interactions is less well known. Dictyostelium cell

  13. Selfish DNA: a pharmaceutical perspective.

    Science.gov (United States)

    Winckler, T

    2013-07-01

    Almost 25 years ago, Theo Dingermann published the discovery of a new mobile genetic element in the unicellular microbe Dictyostelium discoideum in the journal Science. An interesting property of this new molecular parasite, the Dictyostelium Repetitive Element (DRE), was that all integrations were found approximately 50 base pairs (bp) upstream of transfer RNA (tRNA) genes in the D. discoideum genome, thus implying an active targeting mechanism to avoid the disruption of host cell genes by the retrotransposition process. Since then, the facultative multicellular "social amoeba" D. discoideum has become a popular model for analyzing complex cellular functions such as cell movement, chemotaxis, phagocytosis, and cell differentiation, important areas of biomedical research that are often hard to investigate in cells from "higher organisms" including humans. Therefore, progress in the development of methods to study Dictyostelium biology has also provoked research on transposable elements in this organism. Early work on the DRE element suggested that studying its molecular mechanism of site-specific integration might promote human gene therapy technology through the design of integrating gene transfer vectors with low intrinsic genotoxic potential. In this review article, I will briefly review the original research performed on the DRE transposable element in the Dingermann lab and report on how the emergence of genomics technologies and the development of tools to analyze de novo retrotransposition events in D. discoideum cells will expand our knowledge of DRE biology in the future.

  14. An autoregulatory circuit for long-range self-organization in Dictyostelium cell populations.

    Science.gov (United States)

    Sawai, Satoshi; Thomason, Peter A; Cox, Edward C

    2005-01-20

    Nutrient-deprived Dictyostelium amoebae aggregate to form a multicellular structure by chemotaxis, moving towards propagating waves of cyclic AMP that are relayed from cell to cell. Organizing centres are not formed by founder cells, but are dynamic entities consisting of cores of outwardly rotating spiral waves that self-organize in a homogeneous cell population. Spiral waves are ubiquitously observed in chemical reactions as well as in biological systems. Although feedback control of spiral waves in spatially extended chemical reactions has been demonstrated in recent years, the mechanism by which control is achieved in living systems is unknown. Here we show that mutants of the cyclic AMP/protein kinase A pathway show periodic signalling, but fail to organize coherent long-range wave territories, owing to the appearance of numerous spiral cores. A theoretical model suggests that autoregulation of cell excitability mediated by protein kinase A acts to optimize the number of signalling centres.

  15. Dicty_cDB: SSG705 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available NA Score E Sequences producing significant alignments: (bits) Value N AF305060 |AF305060.1 Dictyostelium discoideum Wiscott...quences producing significant alignments: (bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott

  16. Dicty_cDB: SLH341 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 5 ( AF305060 ) Dictyostelium discoideum Wiscott-Aldrich syndrome... 404 0.0 5 ( B...ts) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott-A... 83 8e-15 AC117076_18( AC1170

  17. Dicty_cDB: SFJ736 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 060.1 Dictyostelium discoideum Wiscott-Aldrich syndrome protein (wasA) gene, complete cds. 470 e-129 2 BQ923...1( AF305060 |pid:none) Dictyostelium discoideum Wiscott-A... 81 1e-14 AC117076_18

  18. Dicty_cDB: VFN644 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available A clone:ddv28g12, 3' ... 404 0.0 5 ( AF305060 ) Dictyostelium discoideum Wiscott-...ng significant alignments: (bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott-A..

  19. Dicty_cDB: SFG565 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 5060.1 Dictyostelium discoideum Wiscott-Aldrich syndrome protein (wasA) gene, complete cds. 626 0.0 8 AC1170...bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott-A... 254 4e-77 AC117076_18( AC1

  20. Dicty_cDB: VFA863 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ore E Sequences producing significant alignments: (bits) Value N AF305060 |AF305060.1 Dictyostelium discoideum Wiscott...gnificant alignments: (bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott-A... 83

  1. Dicty_cDB: SFK712 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available deum cDNA clone:dda5o08, 3' e... 404 e-125 2 ( AF305060 ) Dictyostelium discoideum Wiscott-Aldrich syndrome....ore E Sequences producing significant alignments: (bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott

  2. Dicty_cDB: SHE721 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available E Sequences producing significant alignments: (bits) Value N AF305060 |AF305060.1 Dictyostelium discoideum Wiscott...305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott-A... 83 8e-15 AC117076_18( AC117076 |pid:none

  3. Dicty_cDB: SFC789 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ments: (bits) Value N AF305060 |AF305060.1 Dictyostelium discoideum Wiscott-Aldri...ne) Dictyostelium discoideum Wiscott-A... 34 0.031 protein update 2009. 1. 7 PSORT psg: 0.84 gvh: 0.42 alm:

  4. Dicty_cDB: VSJ735 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available |AF305060.1 Dictyostelium discoideum Wiscott-Aldrich syndrome protein (wasA) gene, complete cds. 436 0.0 5 A... AF305060 |pid:none) Dictyostelium discoideum Wiscott-A... 214 2e-54 BC087802_1( BC087802 |pid:none) Xenopus

  5. Dicty_cDB: VSC304 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 05060 |AF305060.1 Dictyostelium discoideum Wiscott-Aldrich syndrome protein (wasA) gene, complete cds. 622 0...bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott-A... 167 1e-44 AC117076_18( AC1

  6. Dicty_cDB: CFG253 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available Value N AF305060 |AF305060.1 Dictyostelium discoideum Wiscott-Aldrich syndrome protein (wasA) gene, complete...ences producing significant alignments: (bits) Value AF305060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott

  7. Dicty_cDB: CFG349 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available its) Value N AF305060 |AF305060.1 Dictyostelium discoideum Wiscott-Aldrich syndrome protein (wasA) gene, com...060_1( AF305060 |pid:none) Dictyostelium discoideum Wiscott-A... 247 4e-64 DQ985464_1( DQ985464 |pid:none) S

  8. NCBI nr-aa BLAST: CBRC-DDIS-03-0190 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-DDIS-03-0190 ref|XP_646956.1| ARID/BRIGHT DNA binding domain-containing protei...n [Dictyostelium discoideum AX4] gb|EAL72978.1| ARID/BRIGHT DNA binding domain-containing protein [Dictyostelium discoideum AX4] XP_646956.1 1e-06 23% ...

  9. Dicty_cDB: Contig-U12991-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ( AF272150 ) Dictyostelium discoideum deliriumA (dlrA) gene, c... 2022 0.0 3 ( BJ...39594 ) TT1EP48TV Tetrahymena thermophila SB210 cDNA libr... 38 10.0 2 >( AF272150 ) Dictyostelium discoideum delirium

  10. NCBI nr-aa BLAST: CBRC-DDIS-01-0111 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-DDIS-01-0111 ref|XP_646081.1| alkaline dihydroceramidase [Dictyostelium discoi...deum AX4] gb|EAL72137.1| alkaline dihydroceramidase [Dictyostelium discoideum AX4] XP_646081.1 1e-164 100% ...

  11. PKC-Mediated ZYG1 Phosphorylation Induces Fusion of Myoblasts as well as of Dictyostelium Cells

    Directory of Open Access Journals (Sweden)

    Aiko Amagai

    2012-01-01

    Full Text Available We have previously demonstrated that a novel protein ZYG1 induces sexual cell fusion (zygote formation of Dictyostelium cells. In the process of cell fusion, involvements of signal transduction pathways via Ca2+ and PKC (protein kinase C have been suggested because zygote formation is greatly enhanced by PKC activators. In fact, there are several deduced sites phosphorylated by PKC in ZYG1 protein. Thereupon, we designed the present work to examine whether or not ZYG1 is actually phosphorylated by PKC and localized at the regions of cell-cell contacts where cell fusion occurs. These were ascertained, suggesting that ZYG1 might be the target protein for PKC. A humanized version of zyg1 cDNA (mzyg1 was introduced into myoblasts to know if ZYG1 is also effective in cell fusion of myoblasts. Quite interestingly, enforced expression of ZYG1 in myoblasts was found to induce markedly their cell fusion, thus strongly suggesting the existence of a common signaling pathway for cell fusion beyond the difference of species.

  12. High fidelity information processing in folic acid chemotaxis of Dictyostelium amoebae.

    Science.gov (United States)

    Segota, Igor; Mong, Surin; Neidich, Eitan; Rachakonda, Archana; Lussenhop, Catherine J; Franck, Carl

    2013-11-06

    Living cells depend upon the detection of chemical signals for their existence. Eukaryotic cells can sense a concentration difference as low as a few per cent across their bodies. This process was previously suggested to be limited by the receptor-ligand binding fluctuations. Here, we first determine the chemotaxis response of Dictyostelium cells to static folic acid gradients and show that they can significantly exceed this sensitivity, responding to gradients as shallow as 0.2% across the cell body. Second, using a previously developed information theory framework, we compare the total information gained about the gradient (based on the cell response) to its upper limit: the information gained at the receptor-ligand binding step. We find that the model originally applied to cAMP sensing fails as demonstrated by the violation of the data processing inequality, i.e. the total information exceeds the information at the receptor-ligand binding step. We propose an extended model with multiple known receptor types and with cells allowed to perform several independent measurements of receptor occupancy. This does not violate the data processing inequality and implies the receptor-ligand binding noise dominates both for low- and high-chemoattractant concentrations. We also speculate that the interplay between exploration and exploitation is used as a strategy for accurate sensing of otherwise unmeasurable levels of a chemoattractant.

  13. Colchicine affects cell motility, pattern formation and stalk cell differentiation in Dictyostelium by altering calcium signaling.

    Science.gov (United States)

    Poloz, Yekaterina; O'Day, Danton H

    2012-04-01

    Previous work, verified here, showed that colchicine affects Dictyostelium pattern formation, disrupts morphogenesis, inhibits spore differentiation and induces terminal stalk cell differentiation. Here we show that colchicine specifically induces ecmB expression and enhances accumulation of ecmB-expressing cells at the posterior end of multicellular structures. Colchicine did not induce a nuclear translocation of DimB, a DIF-1 responsive transcription factor in vitro. It also induced terminal stalk cell differentiation in a mutant strain that does not produce DIF-1 (dmtA-) and after the treatment of cells with DIF-1 synthesis inhibitor cerulenin (100 μM). This suggests that colchicine induces the differentiation of ecmB-expressing cells independent of DIF-1 production and likely through a signaling pathway that is distinct from the one that is utilized by DIF-1. Depending on concentration, colchicine enhanced random cell motility, but not chemotaxis, by 3-5 fold (10-50 mM colchicine, respectively) through a Ca(2+)-mediated signaling pathway involving phospholipase C, calmodulin and heterotrimeric G proteins. Colchicine's effects were not due to microtubule depolymerization as other microtubule-depolymerizing agents did not have these effects. Finally normal morphogenesis and stalk and spore cell differentiation of cells treated with 10 mM colchicine were rescued through chelation of Ca2+ by BAPTA-AM and EDTA and calmodulin antagonism by W-7 but not PLC inhibition by U-73122. Morphogenesis or spore cell differentiation of cells treated with 50 mM colchicine could not be rescued by the above treatments but terminal stalk cell differentiation was inhibited by BAPTA-AM, EDTA and W-7, but not U-73122. Thus colchicine disrupts morphogenesis and induces stalk cell differentiation through a Ca(2+)-mediated signaling pathway involving specific changes in gene expression and cell motility. Copyright © 2011 International Society of Differentiation. Published by Elsevier B

  14. Correlated waves of actin filaments and PIP3 in Dictyostelium cells.

    Science.gov (United States)

    Asano, Yukako; Nagasaki, Akira; Uyeda, Taro Q P

    2008-12-01

    Chemotaxis-deficient amiB-null mutant Dictyostelium cells show two distinct movements: (1) they extend protrusions randomly without net displacements; (2) they migrate persistently and unidirectionally in a keratocyte-like manner. Here, we monitored the intracellular distribution of phosphatidylinositol (3,4,5)-trisphosphate (PIP(3)) to gain insight into roles PIP(3) plays in those spontaneous motilities. In keratocyte-like cells, PIP(3) showed convex distribution over the basal membrane, with no anterior enrichment. In stalled cells, as well as in wild type cells, PIP(3) repeated wave-like changes, including emergence, expansion and disappearance, on the basal membrane. The waves induced lamellipodia when they approached the cell edge, and the advancing speed of the waves was comparable to the migration speed of the keratocyte-like cells. LY294002, an inhibitor of PI3 kinase, abolished PIP(3) waves in stalled cells and stopped keratocyte-like cells. These results together suggested that keratocyte-like cells are "surfing" on the PIP(3) waves by coupling steady lamellipodial protrusions to the PIP(3) waves. Simultaneous live observation of actin filaments and PIP(3) in wild type or stalled amiB(-) cells indicated that the PIP(3) waves were correlated with wave-like distributions of actin filaments. Most notably, PIP(3) waves often followed actin waves, suggesting that PIP(3) induces local depolymerization of actin filaments. Consistent with this idea, cortical accumulation of PIP(3) was often correlated with local retraction of the periphery. We propose that the waves of PIP(3) and actin filaments are loosely coupled with each other and play important roles in generating spontaneous cell polarity. Copyright 2008 Wiley-Liss, Inc.

  15. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB593 (Link to dictyBase) - - - Contig-U02438-1 VFB593E (Link...) Clone ID VFB593 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U02438-1 Ori...0.009 6 AC116986 |AC116986.2 Dictyostelium discoideum chromosome 2 map 2234041-25...sequence. 46 0.031 2 AC115577 |AC115577.2 Dictyostelium discoideum chromosome 2 m...ap 4657875-4914984 strain AX4, complete sequence. 34 0.051 14 AC116960 |AC116960.2 Dictyostelium discoideum

  16. Dictyostelium cells bind a secreted autocrine factor that represses cell proliferation

    Directory of Open Access Journals (Sweden)

    Phillips Jonathan E

    2009-02-01

    Full Text Available Abstract Background Dictyostelium cells secrete the proteins AprA and CfaD. Cells lacking either AprA or CfaD proliferate faster than wild type, while AprA or CfaD overexpressor cells proliferate slowly, indicating that AprA and CfaD are autocrine factors that repress proliferation. CfaD interacts with AprA and requires the presence of AprA to slow proliferation. To determine if CfaD is necessary for the ability of AprA to slow proliferation, whether AprA binds to cells, and if so whether the binding requires the presence of CfaD, we examined the binding and effect on proliferation of recombinant AprA. Results We find that the extracellular accumulation of AprA increases with cell density and reaches a concentration of 0.3 μg/ml near a stationary cell density. When added to wild-type or aprA- cells, recombinant AprA (rAprA significantly slows proliferation at 0.1 μg/ml and higher concentrations. From 4 to 64 μg/ml, the effect of rAprA is at a plateau, slowing but not stopping proliferation. The proliferation-inhibiting activity of rAprA is roughly the same as that of native AprA in conditioned growth medium. Proliferating aprA- cells show saturable binding of rAprA to 92,000 ± 11,000 cell-surface receptors with a KD of 0.03 ± 0.02 μg/ml. There appears to be one class of binding site, and no apparent cooperativity. Native AprA inhibits the binding of rAprA to aprA- cells with a Ki of 0.03 μg/ml, suggesting that the binding kinetics of rAprA are similar to those of native AprA. The proliferation of cells lacking CrlA, a cAMP receptor-like protein, or cells lacking CfaD are not affected by rAprA. Surprisingly, both cell types still bind rAprA. Conclusion Together, the data suggest that AprA functions as an autocrine proliferation-inhibiting factor by binding to cell surface receptors. Although AprA requires CfaD for activity, it does not require CfaD to bind to cells, suggesting the possibility that cells have an AprA receptor and a Cfa

  17. Dictyostelium cells bind a secreted autocrine factor that represses cell proliferation.

    Science.gov (United States)

    Choe, Jonathan M; Bakthavatsalam, Deenadayalan; Phillips, Jonathan E; Gomer, Richard H

    2009-02-02

    Dictyostelium cells secrete the proteins AprA and CfaD. Cells lacking either AprA or CfaD proliferate faster than wild type, while AprA or CfaD overexpressor cells proliferate slowly, indicating that AprA and CfaD are autocrine factors that repress proliferation. CfaD interacts with AprA and requires the presence of AprA to slow proliferation. To determine if CfaD is necessary for the ability of AprA to slow proliferation, whether AprA binds to cells, and if so whether the binding requires the presence of CfaD, we examined the binding and effect on proliferation of recombinant AprA. We find that the extracellular accumulation of AprA increases with cell density and reaches a concentration of 0.3 microg/ml near a stationary cell density. When added to wild-type or aprA- cells, recombinant AprA (rAprA) significantly slows proliferation at 0.1 microg/ml and higher concentrations. From 4 to 64 microg/ml, the effect of rAprA is at a plateau, slowing but not stopping proliferation. The proliferation-inhibiting activity of rAprA is roughly the same as that of native AprA in conditioned growth medium. Proliferating aprA- cells show saturable binding of rAprA to 92,000 +/- 11,000 cell-surface receptors with a KD of 0.03 +/- 0.02 microg/ml. There appears to be one class of binding site, and no apparent cooperativity. Native AprA inhibits the binding of rAprA to aprA- cells with a Ki of 0.03 mug/ml, suggesting that the binding kinetics of rAprA are similar to those of native AprA. The proliferation of cells lacking CrlA, a cAMP receptor-like protein, or cells lacking CfaD are not affected by rAprA. Surprisingly, both cell types still bind rAprA. Together, the data suggest that AprA functions as an autocrine proliferation-inhibiting factor by binding to cell surface receptors. Although AprA requires CfaD for activity, it does not require CfaD to bind to cells, suggesting the possibility that cells have an AprA receptor and a CfaD receptor, and activation of both receptors is

  18. A novel Ras-interacting protein required for chemotaxis and cyclic adenosine monophosphate signal relay in Dictyostelium.

    Science.gov (United States)

    Lee, S; Parent, C A; Insall, R; Firtel, R A

    1999-09-01

    We have identified a novel Ras-interacting protein from Dictyostelium, RIP3, whose function is required for both chemotaxis and the synthesis and relay of the cyclic AMP (cAMP) chemoattractant signal. rip3 null cells are unable to aggregate and lack receptor activation of adenylyl cyclase but are able, in response to cAMP, to induce aggregation-stage, postaggregative, and cell-type-specific gene expression in suspension culture. In addition, rip3 null cells are unable to properly polarize in a cAMP gradient and chemotaxis is highly impaired. We demonstrate that cAMP stimulation of guanylyl cyclase, which is required for chemotaxis, is reduced approximately 60% in rip3 null cells. This reduced activation of guanylyl cyclase may account, in part, for the defect in chemotaxis. When cells are pulsed with cAMP for 5 h to mimic the endogenous cAMP oscillations that occur in wild-type strains, the cells will form aggregates, most of which, however, arrest at the mound stage. Unlike the response seen in wild-type strains, the rip3 null cell aggregates that form under these experimental conditions are very small, which is probably due to the rip3 null cell chemotaxis defect. Many of the phenotypes of the rip3 null cell, including the inability to activate adenylyl cyclase in response to cAMP and defects in chemotaxis, are very similar to those of strains carrying a disruption of the gene encoding the putative Ras exchange factor AleA. We demonstrate that aleA null cells also exhibit a defect in cAMP-mediated activation of guanylyl cyclase similar to that of rip3 null cells. A double-knockout mutant (rip3/aleA null cells) exhibits a further reduction in receptor activation of guanylyl cyclase, and these cells display almost no cell polarization or movement in cAMP gradients. As RIP3 preferentially interacts with an activated form of the Dictyostelium Ras protein RasG, which itself is important for cell movement, we propose that RIP3 and AleA are components of a Ras

  19. A model for cell type localization in the migrating slug of ...

    Indian Academy of Sciences (India)

    PRAKASH

    . Localization of the three major cell types within the migrating slug stage is a dynamic process (Sternfeld 1992;. A model for cell type localization in the migrating slug of Dictyostelium discoideum based on differential chemotactic sensitivity to ...

  20. Evidence for a functional link between Dd-STATa and Dd-PIAS, a Dictyostelium PIAS homologue.

    Science.gov (United States)

    Kawata, Takefumi; Hirano, Tatsunori; Ogasawara, Shun; Aoshima, Ryota; Yachi, Ayako

    2011-09-01

    Several mammalian protein families inhibit the activity of signal transducer and activator of transcription (STAT) proteins. The protein inhibitor of activated STAT (PIAS) was initially identified through its ability to interact with human STAT proteins. We isolated a gene (pisA) encoding a Dictyostelium orthologue of PIAS, Dd-PIAS, which possesses almost all the representative motifs and domains of mammalian PIAS proteins. A Dd-PIAS null mutant strain displays a normal terminal morphology but with accelerated development once cells are aggregated. In contrast, Dd-PIAS overexpressor strains demonstrate delayed aggregation, almost no slug phototaxis, impaired slug motility, and a prolonged slug migration period. This strain is a near phenocopy of the Dd-STATa null mutant, although it eventually forms a fruiting body, albeit inefficiently. The expression of several Dd-STATa-activated genes is upregulated in the Dd-PIAS null mutant and there is ectopic expression of pstAB makers. The concentration of a PIAS-green fluorescent protein (GFP) fusion protein, expressed under the PIAS promoter, is greatest in the pstO cells and gradually decreases with proximity to the tip of the slug and culminant: a pattern diametrically opposite to that of Dd-STATa. Our results suggest a functional interrelationship between Dd-PIAS and Dd-STATa that influences gene expression and development. © 2011 The Authors. Development, Growth & Differentiation © 2011 Japanese Society of Developmental Biologists.

  1. Dicty_cDB: SSL103 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available (bits) Value N AF305060 |AF305060.1 Dictyostelium discoideum Wiscott-Aldrich syndrome protein (wasA) gene, c...ctyostelium discoideum Wiscott-A... 306 4e-82 FN392319_1421( FN392319 |pid:none) Pichia pastoris GS115 chrom

  2. Dicty_cDB: VFE551 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available Value N AF305060 |AF305060.1 Dictyostelium discoideum Wiscott-Aldrich syndrome protein (wasA) gene, complet...ictyostelium discoideum Wiscott-A... 112 4e-24 AC117076_18( AC117076 |pid:none) D

  3. Autonomous and nonautonomous regulation of axis formation by antagonistic signaling via 7-span cAMP receptors and GSK3 in Dictyostelium.

    Science.gov (United States)

    Ginsburg, G T; Kimmel, A R

    1997-08-15

    Early during Dictyostelium development a fundamental cell-fate decision establishes the anteroposterior (prestalk/prespore) axis. Signaling via the 7-transmembrane cAMP receptor CAR4 is essential for creating and maintaining a normal pattern; car4-null alleles have decreased levels of prestalk-specific mRNAs but enhanced expression of prespore genes. car4- cells produce all of the signals required for prestalk differentiation but lack an extracellular factor necessary for prespore differentiation of wild-type cells. This secreted factor decreases the sensitivity of prespore cells to inhibition by the prestalk morphogen DIF-1. At the cell autonomous level, CAR4 is linked to intracellular circuits that activate prestalk but inhibit prespore differentiation. The autonomous action of CAR4 is antagonistic to the positive intracellular signals mediated by another cAMP receptor, CAR1 and/or CAR3. Additional data indicate that these CAR-mediated pathways converge at the serine/threonine protein kinase GSK3, suggesting that the anterior (prestalk)/posterior (prespore) axis of Dictyostelium is regulated by an ancient mechanism that is shared by the Wnt/Fz circuits for dorsoventral patterning during early Xenopus development and establishing Drosophila segment polarity.

  4. Vesicular Trafficking Defects, Developmental Abnormalities, and Alterations in the Cellular Death Process Occur in Cell Lines that Over-Express Dictyostelium GTPase, Rab2, and Rab2 Mutants

    Directory of Open Access Journals (Sweden)

    Katherine Maringer

    2014-08-01

    Full Text Available Small molecular weight GTPase Rab2 has been shown to be a resident of pre-Golgi intermediates and required for protein transport from the ER to the Golgi complex, however, the function of Rab2 in Dictyostelium has yet to be fully characterized. Using cell lines that over-express DdRab2, as well as cell lines over-expressing constitutively active (CA, and dominant negative (DN forms of the GTPase, we report a functional role in vesicular transport specifically phagocytosis, and endocytosis. Furthermore, Rab2 like other GTPases cycles between an active GTP-bound and an inactive GDP-bound state. We found that this GTP/GDP cycle for DdRab2 is crucial for normal Dictyostelium development and cell–cell adhesion. Similar to Rab5 and Rab7 in C. elegans, we found that DdRab2 plays a role in programmed cell death, possibly in the phagocytic removal of apoptotic corpses.

  5. TM9/Phg1 and SadA proteins control surface expression and stability of SibA adhesion molecules in Dictyostelium.

    Science.gov (United States)

    Froquet, Romain; le Coadic, Marion; Perrin, Jackie; Cherix, Nathalie; Cornillon, Sophie; Cosson, Pierre

    2012-02-01

    TM9 proteins form a family of conserved proteins with nine transmembrane domains essential for cellular adhesion in many biological systems, but their exact role in this process remains unknown. In this study, we found that genetic inactivation of the TM9 protein Phg1A dramatically decreases the surface levels of the SibA adhesion molecule in Dictyostelium amoebae. This is due to a decrease in sibA mRNA levels, in SibA protein stability, and in SibA targeting to the cell surface. A similar phenotype was observed in cells devoid of SadA, a protein that does not belong to the TM9 family but also exhibits nine transmembrane domains and is essential for cellular adhesion. A contact site A (csA)-SibA chimeric protein comprising only the transmembrane and cytosolic domains of SibA and the extracellular domain of the Dictyostelium surface protein csA also showed reduced stability and relocalization to endocytic compartments in phg1A knockout cells. These results indicate that TM9 proteins participate in cell adhesion by controlling the levels of adhesion proteins present at the cell surface.

  6. A long-range foresight for the medical application of apoptosis specifically induced by Dd-MRP4, Dictyostelium mitochondrial ribosomal protein S4, to cancer therapy.

    Science.gov (United States)

    Maeda, Yasuo

    2015-02-10

    Apoptosis (programmed cell death) is regarded as ultimate differentiation of the cell. We have recently demonstrated that a targeted delivery of Dd-MRP4 (Dictyostelium mitochondrial ribosomal protein S4) suppresses specifically the proliferation of the human cancer cells, by inducing their apoptotic cell death (Chida et al., 2014, doi:10.1186/1475-2867-14-56). This amazing fact was discovered, simply based on the finding that Dd-MRP4 expression is absolutely required for transition of Dictyostelium cells from growth to differentiation (Chida et al., 2008, doi:10.1186/1471-2156-9-25; Maeda et al., 2013, doi:10.3390/biom3040943). Dd-MRP4 protein has quite unique structural characters, in that it is highly basic (pI: about 11.5) and interestingly has several nuclear-localization signals within the molecule. In this review, we introduce briefly the efficacy of several apoptosis-inducing substances reported thus far for cancer therapy, and speculate the possible mechanisms, by which apoptosis is specifically induced by Dd-MRP4, on the basis of its structural uniqueness. We also discuss several issues to be solved for the medical application of ectopically expressed Dd-MRP4 in human cancer cells.

  7. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB752 (Link to dictyBase) - - - Contig-U14717-1 VFB752E (Link...) Clone ID VFB752 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U14717-1 Ori...s: (bits) Value N AC116984 |AC116984.2 Dictyostelium discoideum chromosome 2 map 2567470-3108875 strain AX4,... complete sequence. 1215 0.0 11 AC115594 |AC115594.2 Dictyostelium discoideum chr...omosome 2 map 4071862-4101005 strain AX4, complete sequence. 113 3e-47 8 AC116920 |AC116920.2 Dictyostelium

  8. Effectiveness of a dynein team in a tug of war helped by reduced load sensitivity of detachment: evidence from the study of bidirectional endosome transport in D. discoideum.

    Science.gov (United States)

    Bhat, Deepak; Gopalakrishnan, Manoj

    2012-08-01

    Bidirectional cargo transport by molecular motors in cells is a complex phenomenon in which the cargo (usually a vesicle) alternately moves in retrograde and anterograde directions. In this case, teams of oppositely pulling motors (e.g., kinesin and dynein) bind to the cargo, simultaneously, and 'coordinate' their activity such that the motion consists of spells of positively and negatively directed segments, separated by pauses of varying duration. A set of recent experiments have analyzed the bidirectional motion of endosomes in the amoeba D. discoideum in detail. It was found that in between directional switches, a team of five to six dyneins stall a cargo against a stronger kinesin in a tug of war, which lasts for almost a second. As the mean detachment time of a kinesin under its stall load was also observed to be ∼1 s, we infer that the collective detachment time of the dynein assembly must also be similar. Here, we analyze this inference from a modeling perspective, using experimentally measured single-molecule parameters as inputs. We find that the commonly assumed exponential load-dependent detachment rate is inconsistent with observations, as it predicts that a five-dynein assembly will detach under its combined stall load in less than a hundredth of a second. A modified model where the load-dependent unbinding rate is assumed to saturate at stall-force level for super-stall loads gives results which are in agreement with experimental data. Our analysis suggests that the load-dependent detachment of a dynein in a team is qualitatively different at sub-stall and super-stall loads, a conclusion which is likely to have implications in other situations involving collective effects of many motors.

  9. Progress Report

    DEFF Research Database (Denmark)

    Duer, Karsten

    1999-01-01

    Progress report describing the work carried out by the Danish participant in the ALTSET project in the period January 1999 to July 1999.......Progress report describing the work carried out by the Danish participant in the ALTSET project in the period January 1999 to July 1999....

  10. Progress Report

    Science.gov (United States)

    2018-05-16

    This report summarizes the annual progress of EPA’s Clean Air Markets Programs such as the Acid Rain Program (ARP) and the Cross-State Air Pollution Rule (CSAPR). EPA systematically collects data on emissions, compliance, and environmental effects, these data are highlighted in our Progress Reports.

  11. Progressive Business

    DEFF Research Database (Denmark)

    Christiansen, Christian O.

    2016-01-01

    Guest Post to the Society for U.S. Intellectual History Blog. Brief introduction to the book Progressive Business: An Intellectual History of the Role of Business in American Society, Oxford U.P., 2015.......Guest Post to the Society for U.S. Intellectual History Blog. Brief introduction to the book Progressive Business: An Intellectual History of the Role of Business in American Society, Oxford U.P., 2015....

  12. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB606 (Link to dictyBase) - - - Contig-U16382-1 VFB606E (Link...) Clone ID VFB606 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16382-1 Ori...ucing significant alignments: (bits) Value N X03281 |X03281.1 Dictyostelium discoideum gene for actin A8. 22...28 0.0 1 AC116957 |AC116957.2 Dictyostelium discoideum chromosome 2 map 1685067-2...2028 0.0 1 AC115579 |AC115579.2 Dictyostelium discoideum chromosome 2 map 4915084-5005461 strain AX4, comple

  13. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB770 (Link to dictyBase) - - - Contig-U16382-1 VFB770E (Link...) Clone ID VFB770 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16382-1 Ori...logy vs DNA Score E Sequences producing significant alignments: (bits) Value N X03281 |X03281.1 Dictyosteliu...m discoideum gene for actin A8. 2230 0.0 1 AC116957 |AC116957.2 Dictyostelium discoideum chromosome 2 map 16...deum actin 15 gene, complete cds. 2030 0.0 1 AC115579 |AC115579.2 Dictyostelium discoideum chromosome 2 map

  14. Measuring progress

    DEFF Research Database (Denmark)

    Wahlberg, Ayo

    2007-01-01

    In recent years, sociological examinations of genetics, therapeutic cloning, neuroscience and tissue engineering have suggested that 'life itself' is currently being transformed through technique with profound implications for the ways in which we understand and govern ourselves and others...... in much the same way that mortality rates, life expectancy or morbidity rates can. By analysing the concrete ways in which human progress has been globally measured and taxonomised in the past two centuries or so, I will show how global stratifications of countries according to their states...

  15. Progressivity Enhanced

    Directory of Open Access Journals (Sweden)

    Marko Hren

    2013-09-01

    Full Text Available Rather than a scientific text, the author contributes a concise memorandum from the originator of the idea who has managed the campaign for the conversion of the military barracks into a creative cluster between 1988 and 2002, when he parted ways with Metelkova due to conflicting views on the center’s future. His views shed light on a distant period of time from a perspective of a participant–observer. The information is abundantly supported by primary sources, also available online. However, some of the presented hypotheses are heavily influenced by his personal experiences of xenophobia, elitism, and predatorial behavior, which were already then discernible on the so-called alternative scene as well – so much so that they obstructed the implementation of progressive programs. The author claims that, in spite of the substantially different reality today, the myths and prejudices concerning Metelkova must be done away with in order to enhance its progressive nature. Above all, the paper calls for an objective view on internal antagonisms, mainly originating in deep class divisions between the users. These make a clear distinction between truly marginal ndividuals and the overambitious beau-bourgeois, as the author labels the large part of users of Metelkova of »his« time. On these grounds, he argues for a robust approach to ban all forms of xenophobia and self-ghettoization.

  16. Progress report

    International Nuclear Information System (INIS)

    Brumovsky, M.

    1979-01-01

    Progress Report, covering the period up to the end of 1979 year, was sent to the IAEA according to the research agreement No. 1971 /CF. This work covered the following fields: preparation and dummy irradiation experiments with a new experimental capsule of ''CHOUCA-M'' type; measurement of temperature fields and design of specimen holders; measurement of neutron energy spectrum in the irradiation place in our experimental reactor of VVR-S type (Nuclear Research Institute) using a set of activation detectors; unification and calibration of the measurement of neutron fluence with the use of Fe, Cu, Mn-Mg and Co-Al monitors; development and improvement of the measuring apparatus and technique for the dynamic testing of pre-cracked specimens with determination of dynamic parameters of fracture mechanics; preparation and manufacture of testing specimens from the Japanese steels - forging, plate and weld metal; preparation of the irradiation capsule for assembling

  17. An N-terminal nuclear localization sequence but not the calmodulin-binding domain mediates nuclear localization of nucleomorphin, a protein that regulates nuclear number in Dictyostelium

    International Nuclear Information System (INIS)

    Myre, Michael A.; O'Day, Danton H.

    2005-01-01

    Nucleomorphin is a novel nuclear calmodulin (CaM)-binding protein (CaMBP) containing an extensive DEED (glu/asp repeat) domain that regulates nuclear number. GFP-constructs of the 38 kDa NumA1 isoform localize as intranuclear patches adjacent to the inner nuclear membrane. The translocation of CaMBPs into nuclei has previously been shown by others to be mediated by both classic nuclear localization sequences (NLSs) and CaM-binding domains (CaMBDs). Here we show that NumA1 possesses a CaMBD ( 171 EDVSRFIKGKLLQKQQKIYKDLERF 195 ) containing both calcium-dependent-binding motifs and an IQ-like motif for calcium-independent binding. GFP-constructs containing only NumA1 residues 1-129, lacking the DEED and CaMBDs, still localized as patches at the internal periphery of nuclei thus ruling out a direct role for the CaMBD in nuclear import. These constructs contained the amino acid residues 48 KKSYQDPEIIAHSRPRK 64 that include both a putative bipartite and classical NLS. GFP-bipartite NLS constructs localized uniformly within nuclei but not as patches. As with previous work, removal of the DEED domain resulted in highly multinucleate cells. However as shown here, multinuclearity only occurred when the NLS was present allowing the protein to enter nuclei. Site-directed mutation analysis in which the NLS was changed to 48 EF 49 abolished the stability of the GFP fusion at the protein but not RNA level preventing subcellular analyses. Cells transfected with the 48 EF 49 construct exhibited slowed growth when compared to parental AX3 cells and other GFP-NumA1 deletion mutants. In addition to identifying an NLS that is sufficient for nuclear translocation of nucleomorphin and ruling out CaM-binding in this event, this work shows that the nuclear localization of NumA1 is crucial to its ability to regulate nuclear number in Dictyostelium

  18. Formation of the outer layer of the Dictyostelium spore coat depends on the inner-layer protein SP85/PsB.

    Science.gov (United States)

    Metcalf, Talibah; Kelley, Karen; Erdos, Gregory W; Kaplan, Lee; West, Christopher M

    2003-02-01

    The Dictyostelium spore is surrounded by a 220 microm thick trilaminar coat that consists of inner and outer electron-dense layers surrounding a central region of cellulose microfibrils. In previous studies, a mutant strain (TL56) lacking three proteins associated with the outer layer exhibited increased permeability to macromolecular tracers, suggesting that this layer contributes to the coat permeability barrier. Electron microscopy now shows that the outer layer is incomplete in the coats of this mutant and consists of a residual regular array of punctate electron densities. The outer layer is also incomplete in a mutant lacking a cellulose-binding protein associated with the inner layer, and these coats are deficient in an outer-layer protein and another coat protein. To examine the mechanism by which this inner-layer protein, SP85, contributes to outer-layer formation, various domain fragments were overexpressed in forming spores. Most of these exert dominant negative effects similar to the deletion of outer-layer proteins, but one construct, consisting of a fusion of the N-terminal and Cys-rich C1 domain, induces a dense mat of novel filaments at the surface of the outer layer. Biochemical studies show that the C1 domain binds cellulose, and a combination of site-directed mutations that inhibits its cellulose-binding activity suppresses outer-layer filament induction. The results suggest that, in addition to a previously described early role in regulating cellulose synthesis, SP85 subsequently contributes a cross-bridging function between cellulose and other coat proteins to organize previously unrecognized structural elements in the outer layer of the coat.

  19. Dicty_cDB: SSB373 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available SS (Link to library) SSB373 (Link to dictyBase) - G00609 DDB0216216 Contig-U04543-1...nk to library) Clone ID SSB373 (Link to dictyBase) Atlas ID - NBRP ID G00609 dictyBase ID DDB0216216 Link to... Contig Contig-U04543-1 Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/...Value N AB016728 |AB016728.1 Dictyostelium discoideum sapA mRNA for saposin A, co... 44 7e-04 12 AC116330 |AC116330.2 Dictyostelium discoideum chromosome 2 map 3191214-3323468 strain AX4, comp

  20. Dicty_cDB: CFE853 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available CF (Link to library) CFE853 (Link to dictyBase) - - - Contig-U16381-1 CFE853F (Link... to Original site) CFE853F 109 - - - - - - Show CFE853 Library CF (Link to library) Clone ID CFE853 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16381-1 Original site URL http://dict...uences producing significant alignments: (bits) Value N X51892 |X51892.1 Dictyost...elium discoideum SP60 gene for spore coat protein. 80 6e-21 2 X52105 |X52105.1 Dictyostelium discoideum SP60

  1. Dicty_cDB: CFH668 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available CF (Link to library) CFH668 (Link to dictyBase) - - - Contig-U13860-1 - (Link to Or...iginal site) - - CFH668Z 651 - - - - Show CFH668 Library CF (Link to library) Clone ID CFH668 (Link to dicty...Base) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U13860-1 Original site URL http://dictycdb.b...s) Value N AC116987 |AC116987.2 Dictyostelium discoideum chromosome 2 map 3527441-3568052 strain AX4, comple...te sequence. 58 1e-11 6 AC116305 |AC116305.2 Dictyostelium discoideum chromosome

  2. Dicty_cDB: AFL826 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available AF (Link to library) AFL826 (Link to dictyBase) - - - - AFL826P (Link to Original s...ite) AFL826F 588 AFL826Z 766 AFL826P 1334 - - Show AFL826 Library AF (Link to library) Clone ID AFL826 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig - Original site URL http://dictycdb.biol.t... Score E Sequences producing significant alignments: (bits) Value N ( BJ346543 ) Dictyostelium discoideum cD...NA clone:dda24d08, 3' ... 1100 0.0 1 ( BJ341682 ) Dictyostelium discoideum cDNA c

  3. Dicty_cDB: AFK740 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available AF (Link to library) AFK740 (Link to dictyBase) - - - Contig-U16381-1 AFK740F (Link... to Original site) AFK740F 107 - - - - - - Show AFK740 Library AF (Link to library) Clone ID AFK740 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16381-1 Original site URL http://dict...es producing significant alignments: (bits) Value N X51892 |X51892.1 Dictyosteliu...m discoideum SP60 gene for spore coat protein. 80 6e-21 2 X52105 |X52105.1 Dictyostelium discoideum SP60 gen

  4. Dicty_cDB: SLF689 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available SL (Link to library) SLF689 (Link to dictyBase) - - - Contig-U16284-1 SLF689Z (Link... to Original site) - - SLF689Z 320 - - - - Show SLF689 Library SL (Link to library) Clone ID SLF689 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16284-1 Original site URL http://dict...DNA Score E Sequences producing significant alignments: (bits) Value N ( AC116305 ) Dictyostelium discoideum... chromosome 2 map 1005175... 478 e-131 1 ( AU053477 ) Dictyostelium discoideum slug cDNA, clone SLI726. 478 e-131 1 ( AU053102 ) Dict

  5. Dicty_cDB: CFH744 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available CF (Link to library) CFH744 (Link to dictyBase) - - - Contig-U16381-1 - (Link to Or...iginal site) CFH744F 118 - - - - - - Show CFH744 Library CF (Link to library) Clone ID CFH744 (Link to dicty...Base) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16381-1 Original site URL http://dictycdb.b...ng significant alignments: (bits) Value N X51892 |X51892.1 Dictyostelium discoide...um SP60 gene for spore coat protein. 80 1e-23 3 AC115685 |AC115685.1 Dictyostelium discoideum chromosome 2 m

  6. Dicty_cDB: SLH678 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available SL (Link to library) SLH678 (Link to dictyBase) - - - Contig-U04159-1 SLH678E (Link... to Original site) - - - - - - SLH678E 373 Show SLH678 Library SL (Link to library) Clone ID SLH678 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U04159-1 Original site URL http://dict... producing significant alignments: (bits) Value N ( AU039970 ) Dictyostelium discoideum slug cDNA, clone SLG...865. 323 e-129 2 ( AU039381 ) Dictyostelium discoideum slug cDNA, clone SLH678. 3

  7. Dicty_cDB: SSC836 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available SS (Link to library) SSC836 (Link to dictyBase) - - - - SSC836E (Link to Original s...ite) - - - - - - SSC836E 502 Show SSC836 Library SS (Link to library) Clone ID SSC836 (Link to dictyBase) Atlas ID - NBRP ID - dict...yBase ID - Link to Contig - Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/...t alignments: (bits) Value N M77492 |M77492.1 Dictyostelium discoideum glycoprotein phosphorylase 2 (glpD) g...ene, complete cds. 779 0.0 1 AC116984 |AC116984.2 Dictyostelium discoideum chromo

  8. Dicty_cDB: VHI285 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VH (Link to library) VHI285 (Link to dictyBase) - - - Contig-U16073-1 - (Link to Or...iginal site) VHI285F 136 - - - - - - Show VHI285 Library VH (Link to library) Clone ID VHI285 (Link to dicty...Base) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16073-1 Original site URL http://dictycdb.b... DNA Score E Sequences producing significant alignments: (bits) Value N ( BJ423035 ) Dict...yostelium discoideum cDNA clone:ddv47i22, 5' ... 72 2e-27 3 ( BJ419916 ) Dictyostelium discoideum cD

  9. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB614 (Link to dictyBase) - - - Contig-U16382-1 VFB614Z (Link... to Original site) - - VFB614Z 219 - - - - Show VFB614 Library VF (Link to library) Clone ID VFB614 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16382-1 Original site URL http://dict...ments: (bits) Value N AC116957 |AC116957.2 Dictyostelium discoideum chromosome 2 ...tin mRNA ITL-1, 3' end. 339 9e-90 1 AC116986 |AC116986.2 Dictyostelium discoideum chromosome 2 map 2234041-2

  10. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFC191 (Link to dictyBase) - - - Contig-U16281-1 VFC191F (Link... to Original site) VFC191F 350 - - - - - - Show VFC191 Library VF (Link to library) Clone ID VFC191 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16281-1 Original site URL http://dict...ts) Value N AC116305 |AC116305.2 Dictyostelium discoideum chromosome 2 map 1005175-1418323 strain AX4, compl... 186 3e-46 AC116305_8( AC116305 |pid:none) Dictyostelium discoideum chromosom...

  11. Survival of the fattest

    DEFF Research Database (Denmark)

    Morgani, Sophie M; Brickman, Joshua M

    2013-01-01

    Experiments on the social amoeba Dictyostelium discoideum show that the origins of lineage bias in this system lie in the nutritional history of individual cells. Clues to the molecular basis for this process suggest similar forces may be at work in early mammalian development.......Experiments on the social amoeba Dictyostelium discoideum show that the origins of lineage bias in this system lie in the nutritional history of individual cells. Clues to the molecular basis for this process suggest similar forces may be at work in early mammalian development....

  12. The Amoebal MAP Kinase Response to Legionella pneumophila Is Regulated by DupA

    OpenAIRE

    Li, Zhiru; Dugan, Aisling S.; Bloomfield, Gareth; Skelton, Jason; Ivens, Alasdair; Losick, Vicki; Isberg, Ralph R.

    2009-01-01

    The amoeba Dictyostelium discoideum can support replication of Legionella pneumophila. Here we identify the dupA gene, encoding a putative tyrosine kinase/dual-specificity phosphatase, in a screen for D. discoideum mutants altered in allowing L. pneumophila intracellular replication. Inactivation of dupA resulted in depressed L. pneumophila growth and sustained hyperphosphorylation of the amoebal MAP kinase ERK1, consistent with loss of a phosphatase activity. Bacterial challenge of wild-type...

  13. Desynchronization of cells on the developmental path triggers the formation of spiral waves of cAMP during Dictyostelium aggregation

    OpenAIRE

    Lauzeral, Jacques; Halloy, José; Goldbeter, Albert

    1997-01-01

    Whereas it is relatively easy to account for the formation of concentric (target) waves of cAMP in the course of Dictyostelium discoideum aggregation after starvation, the origin of spiral waves remains obscure. We investigate a physiologically plausible mechanism for the spontaneous formation of spiral waves of cAMP in D. discoideum. The scenario relies on the developmental path associated with the continuous changes in the activity of enzymes such as adenylate cyclase and phosphodiesterase ...

  14. Dicty_cDB: SLE172 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available d/ 1126 0.0 VHJ195 (VHJ195Q) /CSM/VH/VHJ1-D/VHJ195Q.Seq.d/ 1102 0.0 SLD492 (SLD492Q) /CSM/SL/SLD4-D/SLD492... 0.0 1 ( AU052538 ) Dictyostelium discoideum slug cDNA, clone SLD492. 817 0.0 1 ( C83939 ) Dictyostelium dis

  15. Dicty_cDB: SSI468 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available SS (Link to library) SSI468 (Link to dictyBase) - - - Contig-U16310-1 SSI468Z (Link... to Original site) - - SSI468Z 300 - - - - Show SSI468 Library SS (Link to library) Clone ID SSI468 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16310-1 Original site URL http://dict...gnments: (bits) Value N AC116330 |AC116330.2 Dictyostelium discoideum chromosome 2 map 3191214-3323468 strai...NCING IN PROGRESS ***, 3 unordered pieces. 46 6.0 2 BM029242 |BM029242.1 IpSkn00196 Skin cDNA library Ictalu

  16. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFC265 (Link to dictyBase) - - - Contig-U16459-1 VFC265Z (Link... to Original site) - - VFC265Z 278 - - - - Show VFC265 Library VF (Link to library) Clone ID VFC265 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16459-1 Original site URL http://dict...ology vs DNA Score E Sequences producing significant alignments: (bits) Value N AC123513 |AC123513.1 Dictyos...telium discoideum chromosome 2 map 2779865-2840915 strain AX4, *** SEQUENCING IN PROGRESS ***. 159 9e-77 4 AC117070 |AC117070.2 Dict

  17. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB703 (Link to dictyBase) - - - Contig-U14188-1 VFB703Z (Link... to Original site) - - VFB703Z 680 - - - - Show VFB703 Library VF (Link to library) Clone ID VFB703 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U14188-1 Original site URL http://dict...ENCE, 18 unordered pieces. 36 0.038 5 AC115680 |AC115680.2 Dictyostelium discoideum chromosome 2 map 4415041...4-226K1, *** SEQUENCING IN PROGRESS ***, 52 unordered pieces. 46 0.31 5 AC116977 |AC116977.2 Dict

  18. Chemotaxis in the cellular slime molds : I. The effect of temperature

    NARCIS (Netherlands)

    Konijn, Theo M.

    1965-01-01

    The effect of temperature on chemotaxis in the cellular slime mold Dictyostelium discoideum has been studied by incubating small populations of washed myxamoebae at different temperatures. Droplets containing a cell suspension of known density were deposited on a hydrophobic agar surface. The

  19. Dicty_cDB: VHK596 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 34 4.7 AY698035_1( AY698035 |pid:none) Desmognathus marmoratus isolate 69... 33 6.1 AC116957_68( AC116957 |p...id:none) Dictyostelium discoideum chromoso... 33 8.0 AY612344_1( AY612344 |pid:none) Desmognathus marmoratus

  20. Dicty_cDB: VHA340 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available _1( AY698035 |pid:none) Desmognathus marmoratus isolate 69... 33 5.9 AC116957_68( AC116957 |pid:none) Dictyo...stelium discoideum chromoso... 33 7.6 AY612344_1( AY612344 |pid:none) Desmognathus marmoratus voucher KH...

  1. Dicty_cDB: VHI760 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 7( AC116551 |pid:none) Dictyostelium discoideum chromoso... 79 3e-13 AJ575138_1( AJ575138 |pid:none) Sorda...ria macrospora app gene for a... 50 1e-04 BX571864_113( BX571864 |pid:none) Photorh

  2. Dicty_cDB: SSH868 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 5 k... 329 5e-89 AC116551_17( AC116551 |pid:none) Dictyostelium discoideum chromoso... 95 2e-18 AJ575138_1( AJ575138 |pid:none) Sorda...ria macrospora app gene for a... 58 3e-07 BX571864_113(

  3. Dicty_cDB: SSI186 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available daria macrospora app gene for a... 58 3e-07 BX571864_113... 25 k... 359 e-102 AC116551_17( AC116551 |pid:none) Dictyostelium discoideum chromoso... 98 2e-19 AJ575138_1( AJ575138 |pid:none) Sor

  4. Journal of Biosciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    pp 157-166 Articles. Ammonia differentially suppresses the cAMP chemotaxis of anterior-like cells and prestalk cells in Dictyostelium discoideum · Ira N Feit Erika J Medynski Michael J Rothrock · More Details Abstract Fulltext PDF. A drop assay for chemotaxis to cAMP confirms that both anterior-like cells (ALC) and prestalk ...

  5. Autonomous and non-autonomous traits mediate social cooperation ...

    Indian Academy of Sciences (India)

    2011-07-08

    Jul 8, 2011 ... In the trishanku (triA−) mutant of the social amoeba Dictyostelium discoideum, aggregates are smaller than usual and the spore mass is located mid-way up the stalk, not at the apex. We have monitored aggregate territory size, spore allocation and fruiting body morphology in chimaeric groups of ...

  6. Dicty_cDB: Contig-U16102-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 0 6 ( BJ408668 ) Dictyostelium discoideum cDNA clone:dds46g14, 3' ... 44 3.0 2 ( CV162186 ) CS_hyp_01d11_M13Reverse Blue crab hypoder...08_M13Reverse Blue crab hypodermis, nor... 42 3.6 2 ( AM474408 ) Vitis vinifera contig VV78X173370.5, whole

  7. Dicty_cDB: Contig-U01715-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 0 2 ( AC116924 ) Dictyostelium discoideum chromosome 2 map 6357117... 50 0.17 1 ( FG297596 ) 1108793288766 New World... Screwworm Larvae 9387 EST... 42 0.20 2 ( FG295480 ) 1108770732782 New World...57227 Global-Ocean-Sampling_GS-27-01-01-1... 38 0.71 2 ( FG297390 ) 1108793286096 New World

  8. Dicty_cDB: Contig-U04404-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available lone:VS... 498 e-176 2 ( AU266939 ) Dictyostelium discoideum vegetative cDNA clone:VS... 68 5e-07 1 ( FG2946...24 ) 1108770716152 New World Screwworm Larvae 9387 EST... 42 0.027 2 ( CU469174 ) Pig DNA sequence *** SEQUE

  9. Dicty_cDB: Contig-U05076-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available Dictyostelium discoideum slug cDNA, clone SSF125. 767 0.0 2 ( FG291554 ) 1108793348415 New World Screwworm E...CF-24-HW liver cDNA li... 48 0.34 1 ( FG284835 ) 1108770682807 New World Screwworm Egg 9261 ESTs C... 36 0.9

  10. Dicty_cDB: Contig-U15153-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 42 ) Dictyostelium discoideum gamete cDNA, clone FC-AU21. 400 e-170 4 ( BV426376 ) S237P6125FG3.T0 Portugu...eseWaterDog Canis familiar... 52 0.020 1 ( AC068970 ) Homo sapiens BAC clone RP11-8

  11. Eukaryotic cell flattening

    Science.gov (United States)

    Bae, Albert; Westendorf, Christian; Erlenkamper, Christoph; Galland, Edouard; Franck, Carl; Bodenschatz, Eberhard; Beta, Carsten

    2010-03-01

    Eukaryotic cell flattening is valuable for improving microscopic observations, ranging from bright field to total internal reflection fluorescence microscopy. In this talk, we will discuss traditional overlay techniques, and more modern, microfluidic based flattening, which provides a greater level of control. We demonstrate these techniques on the social amoebae Dictyostelium discoideum, comparing the advantages and disadvantages of each method.

  12. Dicty_cDB: Contig-U04690-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available scauevk mixed_tissue Sebastes... 34 9.9 2 >( AU071707 ) Dictyostelium discoideum slug cDNA, clone SSC319. L... ( AP006852 ) Candida albicans genomic DNA, chromosome 7, compl... 32 9.3 2 ( GE799624 ) EST_scau_evk_888927

  13. Journal of Biosciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    What history tells us XXXVII. ... Classification and expression analyses of homeobox genes from Dictyostelium discoideum .... TORC2 and eisosomes are spatially interdependent, requiring optimal level of phosphatidylinositol .... A sample of 14 schizophrenia patients and 14 healthy control subjects matched for age, sex and ...

  14. NCBI nr-aa BLAST: CBRC-DDIS-02-0043 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-DDIS-02-0043 gb|AAL92369.2| similar to Homo sapiens (Human). Testis intercellular mediator... Peas (Sortilin 1) (Hypothetical protein) (Testis intracellular mediator protein) [Dictyostelium discoideum] AAL92369.2 1e-178 98% ...

  15. Fulltext PDF

    Indian Academy of Sciences (India)

    SEARCHU

    Molecular mechanisms underlying thermal adaptation of xeric animals. 489. Specific and unspecific responses of plants to cold and drought stress. 501. Adaptive ... Arachidonic Acid is a chemoattractant for Dictyostelium discoideum cells. 1281 .... Contribution of root to soil respiration and carbon balance in disturbed and ...

  16. Dicty_cDB: Contig-U14279-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available Dictyostelium discoideum cDNA clone:ddc30k04, 5' ... 200 6e-48 1 ( EW967860 ) LS_13_N05_T7 Headlice composite...tobia irritans 1st Instar Larvae H... 42 3.5 1 ( EW966307 ) SFHL_01_A10_T7 Headlice composite library with a

  17. Dicty_cDB: CFG822 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 115581 |pid:none) Dictyostelium discoideum chromosom... 119 4e-26 BC077988_1( BC077988 |pid:none) Xenopus laevis achalasia...none) Homo sapiens mRNA for achalasia, a... 36 0.47 (Q9NRG9) RecName: Full=Aladin; AltName: Full=Adracalin;

  18. Geothermal progress monitor. Progress report No. 1

    Energy Technology Data Exchange (ETDEWEB)

    1979-12-01

    Progress is reported on the following: electrical uses, direct-heat uses, drilling activities, leases, geothermal loan guarantee program, general activities, and legal, institutional, and regulatory activites. (MHR)

  19. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB886 (Link to dictyBase) - - - Contig-U16382-1 VFB886E (Link...) Clone ID VFB886 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16382-1 Ori...t alignments: (bits) Value N X03281 |X03281.1 Dictyostelium discoideum gene for actin A8. 2234 0.0 1 AC116957 |AC116957.2 Dict...4, complete sequence. 2107 0.0 3 M14146 |M14146.1 D.discoideum actin 15 gene, complete cds. 2034 0.0 1 AC115579 |AC115579.2 Dict...4 0.0 2 AC116986 |AC116986.2 Dictyostelium discoideum chromosome 2 map 2234041-25

  20. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFC115 (Link to dictyBase) - - - Contig-U16382-1 VFC115E (Link...) Clone ID VFC115 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16382-1 Ori...ant alignments: (bits) Value N X03281 |X03281.1 Dictyostelium discoideum gene for actin A8. 954 0.0 7 AC116957 |AC116957.2 Dict...X4, complete sequence. 906 0.0 9 M14146 |M14146.1 D.discoideum actin 15 gene, complete cds. 890 0.0 7 AC115579 |AC115579.2 Dict...0.0 7 U25660 |U25660.1 Dictyostelium discoideum actin gene, partial cds. 866 0.0

  1. Dicty_cDB: CHD534 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available CH (Link to library) CHD534 (Link to dictyBase) - - - Contig-U15540-1 CHD534E (Link...) Clone ID CHD534 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U15540-1 Ori...nts: (bits) Value N AC114263 |AC114263.2 Dictyostelium discoideum chromosome 2 ma...p 215673-367476 strain AX4, complete sequence. 40 1e-05 6 AC117081 |AC117081.2 Dictyostelium discoideum chro...mosome 2 map 5862124-6045772 strain AX4, complete sequence. 40 2e-05 5 AJ277590 |AJ277590.1 Dictyostelium di

  2. Progressive Pigmentary Purpura

    Science.gov (United States)

    ... Category: Share: Yes No, Keep Private Progressive Pigmentary Purpura Share | Progressive pigmentary purpura (we will call it PPP) is a group ... conditions ( Schamberg's disease , Lichenoid dermatitis of Gourgerot-Blum, purpura annularis telangiectodes of Majocchi and Lichen aureus). Schamberg's ...

  3. Primary Progressive Aphasia

    Science.gov (United States)

    ... which cause different symptoms. Semantic variant primary progressive aphasia Symptoms include these difficulties: Comprehending spoken or written ... word meanings Naming objects Logopenic variant primary progressive aphasia Symptoms include: Having difficulty retrieving words Frequently pausing ...

  4. The progressive tax

    OpenAIRE

    Estrada, Fernando

    2010-01-01

    This article describes the argumentative structure of Hayek on the relationship between power to tax and the progressive tax. It is observed throughout its work giving special attention to two works: The Constitution of Liberty (1959) and Law, Legislation and Liberty, vol3; The Political Order of Free People, 1979) Hayek describes one of the arguments most complete information bout SFP progressive tax systems (progressive tax). According to the author the history of the tax progressive system...

  5. Progressive Multifocal Leukoencephalopathy

    Science.gov (United States)

    ... SEARCH Definition Treatment Prognosis Clinical Trials Organizations Publications Definition Progressive multifocal leukoencephalopathy (PML) is a disease of the white matter of the brain, caused by a virus infection ...

  6. Progressive geometric algorithms

    NARCIS (Netherlands)

    Alewijnse, S.P.A.; Bagautdinov, T.M.; de Berg, M.T.; Bouts, Q.W.; ten Brink, Alex P.; Buchin, K.A.; Westenberg, M.A.

    2015-01-01

    Progressive algorithms are algorithms that, on the way to computing a complete solution to the problem at hand, output intermediate solutions that approximate the complete solution increasingly well. We present a framework for analyzing such algorithms, and develop efficient progressive algorithms

  7. Progressive geometric algorithms

    NARCIS (Netherlands)

    Alewijnse, S.P.A.; Bagautdinov, T.M.; Berg, de M.T.; Bouts, Q.W.; Brink, ten A.P.; Buchin, K.; Westenberg, M.A.

    2014-01-01

    Progressive algorithms are algorithms that, on the way to computing a complete solution to the problem at hand, output intermediate solutions that approximate the complete solution increasingly well. We present a framework for analyzing such algorithms, and develop efficient progressive algorithms

  8. White matter lesion progression

    DEFF Research Database (Denmark)

    Hofer, Edith; Cavalieri, Margherita; Bis, Joshua C

    2015-01-01

    10 cohorts. To assess the relative contribution of genetic factors to progression of WML, we compared in 7 cohorts risk models including demographics, vascular risk factors plus single-nucleotide polymorphisms that have been shown to be associated cross-sectionally with WML in the current......BACKGROUND AND PURPOSE: White matter lesion (WML) progression on magnetic resonance imaging is related to cognitive decline and stroke, but its determinants besides baseline WML burden are largely unknown. Here, we estimated heritability of WML progression, and sought common genetic variants...... associated with WML progression in elderly participants from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium. METHODS: Heritability of WML progression was calculated in the Framingham Heart Study. The genome-wide association study included 7773 elderly participants from...

  9. Progress test utopia.

    Science.gov (United States)

    van der Vleuten, Cees; Freeman, Adrian; Collares, Carlos Fernando

    2018-04-01

    This paper discusses the advantages of progress testing. A utopia is described where medical schools would work together to develop and administer progress testing. This would lead to a significant reduction of cost, an increase in the quality of measurement and phenomenal feedback to learner and school. Progress testing would also provide more freedom and resources for more creative in-school assessment. It would be an educationally attractive alternative for the creation of cognitive licensing exams. A utopia is always far away in the future, but by formulating a vision for that future we may engage in discussions on how to get there.

  10. Waste management progress report

    International Nuclear Information System (INIS)

    1997-06-01

    During the Cold War era, when DOE and its predecessor agencies produced nuclear weapons and components, and conducted nuclear research, a variety of wastes were generated (both radioactive and hazardous). DOE now has the task of managing these wastes so that they are not a threat to human health and the environment. This document is the Waste Management Progress Report for the U.S. Department of Energy dated June 1997. This progress report contains a radioactive and hazardous waste inventory and waste management program mission, a section describing progress toward mission completion, mid-year 1997 accomplishments, and the future outlook for waste management

  11. Progressive Finland sees progress with nuclear projects

    Energy Technology Data Exchange (ETDEWEB)

    Dalton, David [NucNet, Brussels (Belgium)

    2016-02-15

    The Finnish Hanhikivi-1 reactor project is firmly on track and a licence has been granted for construction of a final disposal facility for spent nuclear fuel - the first final repository in the world to enter the construction phase. Significant progress has been made with plans for Finland to build its sixth nuclear reactor unit at Hanhikivi. Fennovoima's licensing manager Janne Liuko said the company expects to receive the construction licence for the Generation III+ Hanhikivi-1 plant in late 2017. The application was submitted to the Finnish Ministry of Employment and the Economy in June 2015.

  12. Progression of Liver Disease

    Science.gov (United States)

    ... Legacy Society Make Gifts of Stock Donate Your Car Personal Fundraising Partnership & Support Share Your Story Spread the Word Give While You Shop Contact Us Donate Now The Progression of Liver ...

  13. Progression of Liver Disease

    Science.gov (United States)

    ... Liver Function Tests Clinical Trials Liver Transplant FAQs Medical Terminology Diseases of the Liver Alagille Syndrome Alcohol-Related ... the Liver The Progression of Liver Disease FAQs Medical Terminology HOW YOU CAN HELP Sponsorship Ways to Give ...

  14. Progress report for '89

    International Nuclear Information System (INIS)

    Podest, M.

    1990-08-01

    The 1989 Progress Report presents the most important scientific and technical achievements of the Nuclear Research Institute's research work. Some specialized products prepared at or fabricated by the NRI are mentioned as well. (author). 24 figs., 8 tabs., 101 refs

  15. Progress report, Physics Division

    International Nuclear Information System (INIS)

    1986-03-01

    This report reviews events and progress in the following areas: development of the TASCC facility; experimental and theoretical nuclear physics research; radionuclide standardization; condensed matter research; applied mathematics; and computer facility operation

  16. Progress for the Paralyzed

    Science.gov (United States)

    ... Contents Latest Advances Help People Regain Function and Independence Founded in 2000, the National Institute for Biomedical ... More "NIBIB Robotics" Articles Progress for the Paralyzed / College Athlete Stands Again…On His Own! / Coffee to ...

  17. Progress report 1979

    International Nuclear Information System (INIS)

    1979-01-01

    Progress report on the meetings and working groups of DAF in 1979, e.g. engineering and industry, public and press, law and administration, business and industry, international cooperation in Europe and with the USA. (GL) [de

  18. Progress report 1985

    International Nuclear Information System (INIS)

    1986-01-01

    This progress report of the nuclear physics institute includes five basic subjects: theoretical physics, high energy and intermediate energy physics, nuclear physics, combined research physics and instrumentation (microelectronics, imaging, multidetectors, scintillators,...) [fr

  19. Modeling Progress in AI

    OpenAIRE

    Brundage, Miles

    2015-01-01

    Participants in recent discussions of AI-related issues ranging from intelligence explosion to technological unemployment have made diverse claims about the nature, pace, and drivers of progress in AI. However, these theories are rarely specified in enough detail to enable systematic evaluation of their assumptions or to extrapolate progress quantitatively, as is often done with some success in other technological domains. After reviewing relevant literatures and justifying the need for more ...

  20. [Progressive visual agnosia].

    Science.gov (United States)

    Sugimoto, Azusa; Futamura, Akinori; Kawamura, Mitsuru

    2011-10-01

    Progressive visual agnosia was discovered in the 20th century following the discovery of classical non-progressive visual agnosia. In contrast to the classical type, which is caused by cerebral vascular disease or traumatic injury, progressive visual agnosia is a symptom of neurological degeneration. The condition of progressive visual loss, including visual agnosia, and posterior cerebral atrophy was named posterior cortical atrophy (PCA) by Benson et al. (1988). Progressive visual agnosia is also observed in semantic dementia (SD) and other degenerative diseases, but there is a difference in the subtype of visual agnosia associated with these diseases. Lissauer (1890) classified visual agnosia into apperceptive and associative types, and it in most cases, PCA is associated with the apperceptive type. However, SD patients exhibit symptoms of associative visual agnosia before changing to those of semantic memory disorder. Insights into progressive visual agnosia have helped us understand the visual system and discover how we "perceive" the outer world neuronally, with regard to consciousness. Although PCA is a type of atypical dementia, its diagnosis is important to enable patients to live better lives with appropriate functional support.

  1. The cAMP-induced G protein subunits dissociation monitored in live Dictyostelium cells by BRET reveals two activation rates, a positive effect of caffeine and potential role of microtubules.

    Science.gov (United States)

    Tariqul Islam, A F M; Yue, Haicen; Scavello, Margarethakay; Haldeman, Pearce; Rappel, Wouter-Jan; Charest, Pascale G

    2018-08-01

    To study the dynamics and mechanisms controlling activation of the heterotrimeric G protein Gα2βγ in Dictyostelium in response to stimulation by the chemoattractant cyclic AMP (cAMP), we monitored the G protein subunit interaction in live cells using bioluminescence resonance energy transfer (BRET). We found that cAMP induces the cAR1-mediated dissociation of the G protein subunits to a similar extent in both undifferentiated and differentiated cells, suggesting that only a small number of cAR1 (as expressed in undifferentiated cells) is necessary to induce the full activation of Gα2βγ. In addition, we found that treating cells with caffeine increases the potency of cAMP-induced Gα2βγ activation; and that disrupting the microtubule network but not F-actin inhibits the cAMP-induced dissociation of Gα2βγ. Thus, microtubules are necessary for efficient cAR1-mediated activation of the heterotrimeric G protein. Finally, kinetics analyses of Gα2βγ subunit dissociation induced by different cAMP concentrations indicate that there are two distinct rates at which the heterotrimeric G protein subunits dissociate when cells are stimulated with cAMP concentrations above 500 nM versus only one rate at lower cAMP concentrations. Quantitative modeling suggests that the kinetics profile of Gα2βγ subunit dissociation results from the presence of both uncoupled and G protein pre-coupled cAR1 that have differential affinities for cAMP and, consequently, induce G protein subunit dissociation through different rates. We suggest that these different signaling kinetic profiles may play an important role in initial chemoattractant gradient sensing. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. Physicians’ Progress Notes

    DEFF Research Database (Denmark)

    Bansler, Jørgen; Havn, Erling C.; Mønsted, Troels

    2013-01-01

    in patient care, they have not dealt specifically with the role, structure, and content of the progress notes. As a consequence, CSCW research has not yet taken fully into account the fact that progress notes are coordinative artifacts of a rather special kind, an open-ended chain of prose texts, written...... sequentially by cooperating physicians for their own use as well as for that of their colleagues. We argue that progress notes are the core of the medical record, in that they marshal and summarize the overwhelming amount of data that is available in the modern hospital environment, and that their narrative...... format is uniquely adequate for the pivotal epistemic aspect of cooperative clinical work: the narrative format enables physicians to not only record ‘facts’ but also—by filtering, interpreting, organizing, and qualifying information—to make sense and act concertedly under conditions of uncertainty...

  3. Chronic progressive multiple sclerosis

    International Nuclear Information System (INIS)

    Buffoli, A.; Micheletti, E.; Capra, R.; Mattioli, F.; Marciano', N.

    1991-01-01

    A long-lasting immunological suppression action seems to be produced by total lymphoid irradiation; some authors emphasize the favorable effect of this treatment on chronic progressive multiple sclerosis. In order to evaluate the actual role of TLI, 6 patients affected with chronic progressive multiple sclerosis were submitted to TLI with shaped and personalized fields at the Istituto del Radio, University of Brescia, Italy. The total dose delivered was 19.8 Gy in 4 weeks, 1.8 Gy/day, 5d/w; a week elapsed between the first and the second irradiation course. Disability according to Kurtzke scale was evaluated, together with blood lymphocyte count and irradiation side-effects, over a mean follow-up period of 20.8 months (range: 13-24). Our findings indicate that: a) disease progression was not markedly reduced by TLI; b) steroid hormones responsivity was restored after irradiation, and c) side-effects were mild and tolerable

  4. Progress in physical chemistry

    CERN Document Server

    Hempelmann, Rolf

    2008-01-01

    Progress in Physical Chemistry is a collection of recent ""Review Articles"" published in the ""Zeitschrift für Physikalische Chemie"". The second volume of Progress in Physical Chemistry is a collection of thematically closely related minireview articles written by the members of the Collaborative Research Centre (SFB) 277 of the German Research Foundation (DFG). These articles are based on twelve years of intense coordinated research efforts. Central topics are the synthesis and the characterization of interface-dominated, i.e. nanostructured materials, mainly in the solid state but also as

  5. Progress report 1981

    International Nuclear Information System (INIS)

    Chalupka, A.; Dirninger, G.

    1982-01-01

    The progress report describes the scientific work and research results of the institute for radium research and nuclear physics of the Austrian Academy of Sciences for the period of 1981. The progress report covers the subject areas of nuclear theory, nuclear model calculations, experimental nuclear physics and neutron involved reactions, medium energy physics, instrumentation and detectors, evaluation of nuclear data and numerical data processing, dating, applications in medicine, dosimetry and environmental studies. A list of publications of this institute is given. (A.N.)

  6. Annual progress report 1981

    International Nuclear Information System (INIS)

    1982-01-01

    This annual progress report of the CEA Protection and Nuclear Safety Institut outlines a brief description of the progress made in each section of the Institut. Research activities of the Protection department include, radiation effects on man, radioecology and environment radioprotection techniques. Research activities of the Nuclear Safety department include, reactor safety analysis, fuel cycle facilities safety analysis, safety research programs. The third section deals with nuclear material security including security of facilities, security of nuclear material transport and monitoring of nuclear material management [fr

  7. Progress report 1982

    International Nuclear Information System (INIS)

    Chalupka, A.; Wild, E.; Dirninger, G.

    1983-01-01

    The progress report describes the scientific work and research results of the institute for radium research and nuclear physics of the Austrian Academy of Sciences for the period of 1982. The progress report covers the subject areas of nuclear theory, nuclear model calculations, experimental nuclear physics and neutron involved reactions, medium energy physics, instrumentation and detectors, evaluation of nuclear data and numerical data processing, dating, applications in medicine, dosimetry and environmental studies. A list of publications of this institute is given. (A.N.)

  8. 1985. Annual progress report

    International Nuclear Information System (INIS)

    1986-01-01

    This annual progress report of the CEA Protection and Nuclear Safety Institut outlines a description of the progress made in each sections of the Institut Research activities of the different departments include: reactor safety analysis, fuel cycle facilities analysis; and associated safety research programs (criticality, sites, transport ...), radioecology and environmental radioprotection techniques; data acquisition on radioactive waste storage sites; radiation effects on man, studies on radioprotection techniques; nuclear material security including security of facilities, security of nuclear material transport, and monitoring of nuclear material management; nuclear facility decommissioning; and finally the public information [fr

  9. Dicty_cDB: AFL289 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available AF (Link to library) AFL289 (Link to dictyBase) - - - - AFL289F (Link to Original s...ite) AFL289F 123 - - - - - - Show AFL289 Library AF (Link to library) Clone ID AFL289 (Link to dictyBase) Atlas ID - NBRP ID - dict...yBase ID - Link to Contig - Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/... E Sequences producing significant alignments: (bits) Value N X51892 |X51892.1 Dict...yostelium discoideum SP60 gene for spore coat protein. 82 5e-29 2 X52105 |X52105.1 Dictyostelium discoideu

  10. Dicty_cDB: SLD420 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available SL (Link to library) SLD420 (Link to dictyBase) - - - Contig-U16325-1 SLD420E (Link... to Original site) - - - - - - SLD420E 434 Show SLD420 Library SL (Link to library) Clone ID SLD420 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16325-1 Original site URL http://dict... 7 Homology vs DNA Score E Sequences producing significant alignments: (bits) Value N ( AF066071 ) Dict...yostelium discoideum SP85 (pspB) gene, comple... 860 0.0 1 ( AC117075 ) Dictyostelium

  11. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB585 (Link to dictyBase) - - - Contig-U09875-1 VFB585Z (Link... to Original site) - - VFB585Z 664 - - - - Show VFB585 Library VF (Link to library) Clone ID VFB585 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U09875-1 Original site URL http://dict...Score E Sequences producing significant alignments: (bits) Value N AC116551 |AC116551.2 Dictyostelium discoi...ces producing significant alignments: (bits) Value AC116551_43( AC116551 |pid:none) Dictyostelium discoideum

  12. Dicty_cDB: Contig-U15060-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 000227 |pid:none) Bacillus cereus Q1, complete ge... 114 3e-23 B83991( B83991 ) glycolate oxidase subunit BH2730 [imported...ana interm... 56 2e-15 5 ( AF211126 ) Carsonella ruddii natural-host Bactericera cocker....psnkfvpqrlfqq*fvf tiqrkln*vllgnqvkvl*vnsqvqwlksifitfvplisrmfvslslvskvqrrl*isie lqfsissprmlplv*vlllvklgpkkdmi... la... 1074 0.0 1 ( AB000109 ) Dictyostelium discoideum mitochondrial DNA, compl... 1074 0.0 1 ( BJ412759 ) Dictyosteli...7, 3' ... 731 0.0 1 ( DQ336395 ) Dictyostelium citrinum mitochondrion, complete ge... 456 0.0 3 ( BJ387435 ) Dictyosteli

  13. BARC progress report - 1998

    Energy Technology Data Exchange (ETDEWEB)

    Kalyane, V L [comp.; Library and Information Services Div., Bhabha Atomic Research Centre, Mumbai (India)

    1999-04-01

    This report is a compilation of the progress in various major activities and Research and Development programmes of the different Divisions of the Bhabha Atomic Research Centre, Mumbai. The list of publications and papers presented at the various conferences, symposia, workshops and papers published in journal by the staff members of the Divisions are also given. (author) figs., tabs.

  14. BARC progress report - 1998

    International Nuclear Information System (INIS)

    Kalyane, V.L.

    1999-04-01

    This report is a compilation of the progress in various major activities and Research and Development programmes of the different Divisions of the Bhabha Atomic Research Centre, Mumbai. The list of publications and papers presented at the various conferences, symposia, workshops and papers published in journal by the staff members of the Divisions are also given. (author)

  15. Internationalisering og progression

    DEFF Research Database (Denmark)

    Wilken, Lisanne; Tange, Hanne

    2014-01-01

    means that programs can attract students from outside Denmark, and these students often come from different academic backgrounds. To investigate how these changes are affecting the way professors who teach on interdisciplinary international masters programs conceive student progress, we carried out semi...

  16. Progress report of CJD

    International Nuclear Information System (INIS)

    2002-01-01

    This paper is the progress report of the Russian Nuclear Data Center at F.E.I., Obninsk. Evaluations have been made for dosimetry reactions and neutron reactions. Analysis of the spectra and the production cross sections were made. (a.n.)

  17. Progress report 1982

    International Nuclear Information System (INIS)

    Paul, H.

    1983-01-01

    This progress report describes the scientific work and research results done by the institute for experimental physics, atom and nuclear physics of the Johannes-Kepler-Universitaet Linz in the period of 1982. The covered subject areas are ionization by cations, investigations of surface areas by light ions, measurement of stopping power in solids, data acquisition and aerosol physics. (A.N.)

  18. Recent progress in Biophysics

    International Nuclear Information System (INIS)

    Bemski, G.

    1980-03-01

    Recent progress in biophysics is reviewed, and three examples of the use of physical techniques and ideas in biological research are given. The first one deals with the oxygen transporting protein-hemoglobin, the second one with photosynthesis, and the third one with image formation, using nuclear magnetic resonance. (Author) [pt

  19. MCNP Progress & Performance Improvements

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Forrest B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bull, Jeffrey S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rising, Michael Evan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-04-14

    Twenty-eight slides give information about the work of the US DOE/NNSA Nuclear Criticality Safety Program on MCNP6 under the following headings: MCNP6.1.1 Release, with ENDF/B-VII.1; Verification/Validation; User Support & Training; Performance Improvements; and Work in Progress. Whisper methodology will be incorporated into the code, and run speed should be increased.

  20. Scales of Progress

    Science.gov (United States)

    Jung, Lee Ann

    2018-01-01

    What is Goal Attainment Scaling? In this article, Lee Ann Jung defines it as a way to measure a student's progress toward an individualized goal. Instead of measuring a skill at a set time (for instance, on a test or other assignment), Goal Attainment Scaling tracks the steps a student takes over the course of a year in a targeted skill. Together,…

  1. Progressive Retirement Programme

    CERN Document Server

    HR Department

    2009-01-01

    Following the Standing Concertation Committee meeting of 2 December 2008, please note that the Progressive Retirement Programme has been extended by one year, i.e. until 31 March 2010. Further information is available on : https://hr-services.web.cern.ch/hr-services/services-Ben/prp/prp.asp HR Department, tel. 73903

  2. Progress Report 1994

    International Nuclear Information System (INIS)

    1995-01-01

    This document is the 1994 annual progress report of the CEA-Direction of Waste Management (DGD). It comprises four chapters. The first chapter is a general presentation of radioactive wastes, of the management of liquid effluents, solid wastes, sealed sources, of the relations with the ANDRA (The French Agency for the Management of Radioactive Wastes), and of the research and development studies in progress for the improvement of waste management. The second chapter concerns the spent fuels and their reprocessing, in particular AGR and PWR type reactor fuels, the ''Caramel'' fuel from Osiris reactor and the cover elements from the Rapsodie reactor core. The long time storage of ancient fuels is also discussed. The third chapter concerns the dismantling of decommissioned installations, the actions in progress and the planning of dismantling actions up to the year 2000. Chapter four is devoted to the management of wastes from the Direction of Military Applications (DAM), the actions in progress in the different DAM centers and the cleansing projects at Marcoule plant. (J.S.). 5 figs., 28 tabs., 21 photos., 3 appendix

  3. Progress report 1979

    International Nuclear Information System (INIS)

    1980-12-01

    This progress report deals with technical and research work done at the AAEC Research Establishment in the twelve month period ending September 30, 1979. Work done in the following research divisions is reported: Applied Maths and Computing, Chemical Technology, Engineering Research, Environmental Science, Instrumentation and Control, Isotope, Materials and Physics

  4. Progress in optics

    CERN Document Server

    Wolf, Emil

    2015-01-01

    The Progress in Optics series contains more than 300 review articles by distinguished research workers, which have become permanent records for many important developments, helping optical scientists and optical engineers stay abreast of their fields. Comprehensive, in-depth reviewsEdited by the leading authority in the field

  5. Progress in inertial fusion

    International Nuclear Information System (INIS)

    Hogan, W.; Storm, E.

    1985-10-01

    The requirements for high gain in inertial confinement are given in terms of target implosion requirements. Results of experimental studies of the laser/target interaction and of the dynamics of laser implosion. A report of the progress of advanced laser development is also presented. 3 refs., 8 figs., 1 tab

  6. Progress report 1978

    International Nuclear Information System (INIS)

    1979-01-01

    The Studsvik Science Research Laboratory herewith presents its progress report for 1978. The report summarizes the current projects carried out by the research groups working at the laboratory. Projects within the following fields are presented: neutron physics, neutron absorption and scattering, radiation chemistry, radiation damage studies, radioactivity and theoretical studies of condensed matter. (E.R.)

  7. Progress report 1981

    International Nuclear Information System (INIS)

    After giving a brief description of operations of an improvements to the University of Alberta nuclear physics facilities, this report summarizes the principal research programs. These include work on neutron scattering, thorium 232 fission, iodine 123 production. Progress towards the construction of MARIA, the Medical Accelerator Research Institute in Alberta, is described, and research on relativistic heavy ions is summarized

  8. BARC progress report - 1997

    Energy Technology Data Exchange (ETDEWEB)

    Kalyane, V L [comp.; Library and Information Services Div., Bhabha Atomic Research Centre, Mumbai (India)

    1998-07-01

    This report is a compilation of the progress in various major activities and Research and Development programmes of the different Divisions of the Bhabha Atomic Research Centre, Mumbai. The list of publications and papers presented at the various conferences, symposia, workshops and papers published in journal by the staff members of the Divisions are also given. (author) figs., tabs.

  9. BARC progress report - 1997

    International Nuclear Information System (INIS)

    Kalyane, V.L.

    1998-07-01

    This report is a compilation of the progress in various major activities and Research and Development programmes of the different Divisions of the Bhabha Atomic Research Centre, Mumbai. The list of publications and papers presented at the various conferences, symposia, workshops and papers published in journal by the staff members of the Divisions are also given. (author)

  10. Response: Progress Takes Time.

    Science.gov (United States)

    Rist, Marilee C.

    1984-01-01

    Although declining enrollment and administrative seniority have hampered efforts to eliminate sex discrimination in employment practices in three Long Island, New York, school systems (Commack, Smithtown, and Bay Shore), progress is being made. Because of the Reagan administration's lack of support for affirmative action, however, litigation…

  11. Progressive Web applications

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    Progressive Web Applications are native-like applications running inside of a browser context. In my presentation I would like describe their characteristics, benchmarks and building process using a quick and simple case study example with focus on Service Workers api.

  12. "Paideia," Progress, Puzzlement

    Science.gov (United States)

    Hrachovec, Herbert

    2018-01-01

    Platonic "paideia" is a mainstream concept in traditional philosophy and humanistic circles generally. It is closely connected with social progress brought about by the dynamics of enlightenment and self-fulfillment, symbolized by the allegory of the cave. The main contention of this paper is that the philosophical grammar of this simile…

  13. Are Forecast Updates Progressive?

    NARCIS (Netherlands)

    C-L. Chang (Chia-Lin); Ph.H.B.F. Franses (Philip Hans); M.J. McAleer (Michael)

    2010-01-01

    textabstractMacro-economic forecasts typically involve both a model component, which is replicable, as well as intuition, which is non-replicable. Intuition is expert knowledge possessed by a forecaster. If forecast updates are progressive, forecast updates should become more accurate, on average,

  14. Progress report 1979

    International Nuclear Information System (INIS)

    1980-12-01

    This progress report deals with service oriented work performed at the AAEC Research Establishment in the twelve month period ending September 30, 1979. Services provided by the Engineering Services Division, the Safety Department, Site Information Services Department and Commercial Applications are described

  15. Progression og underviserkompetencer

    Directory of Open Access Journals (Sweden)

    Lene Tortzen Bager

    2014-03-01

    Full Text Available På baggrund af en kvalitativ interviewundersøgelse af undervisere ved Aarhus Universitet lavet i 2012, tematiserer artiklen, hvordan undervisere udvikler deres faglige og pædagogiske kompetencer i forhold til at kunne skabe progression inden for innovation og entreprenørskab forstået enten som didaktik, arbejdsformer i faglige forløb eller som fag på universitetet. I arbejdet med progression er det en udfordring at integrere de nye faglige dimensioner i det kernefaglige felt. Den seneste model for progression inden for innovation og entreprenør-skab siger, at det er den lærendes generelle erfaringsniveau, der er den afgørende progressionsskabende faktor (Progressionsmodellen, Fonden for Entreprenørskab, 2013b. Samtidig skelner international forskning inden for studiekompetenceområdet mellem niveauer, hvor indlejret viden er det mest avancerede kompetenceniveau (Barrie, 2002.Ifølge progressionsmodellen og den nævnte kompetenceforskning er erfaring og dybt integreret læring altså centrale dimensioner i progression. Men hvad er underviserens rolle heri? Underviserens professionelle udviklingsarbejde forekommer at være underbelyst i forhold til, at underviseren er den legitime garant for integrationen af nye faglige dimensioner og for den studerendes kompetenceniveau. Interviewundersøgelsen forholder sig til spørgsmålet om progression gennem de deltagende underviseres beskrivelse af betydningslag i entreprenørskabsbegrebet koblet til de praksisformer i undervisningen, der knytter sig hertil samt et indblik i undervisernes refleksioner over deres kompetenceudviklingsprocesser. Artiklens bidrag til progression er at se underviserens motivation og kompetenceudvikling som forudsætninger herfor.     Based on a qualitative study of five teachers in the Faculty of Arts at Aarhus University that took place during 2012, the article thematizes how teachers develop their professional and educational qualifications in innovation and

  16. Evaluation of keratoconus progression.

    Science.gov (United States)

    Shajari, Mehdi; Steinwender, Gernot; Herrmann, Kim; Kubiak, Kate Barbara; Pavlovic, Ivana; Plawetzki, Elena; Schmack, Ingo; Kohnen, Thomas

    2018-06-01

    To define variables for the evaluation of keratoconus progression and to determine cut-off values. In this retrospective cohort study (2010-2016), 265 eyes of 165 patients diagnosed with keratoconus underwent two Scheimpflug measurements (Pentacam) that took place 1 year apart ±3 months. Variables used for keratoconus detection were evaluated for progression and a correlation analysis was performed. By logistic regression analysis, a keratoconus progression index (KPI) was defined. Receiver-operating characteristic curve (ROC) analysis was performed and Youden Index calculated to determine cut-off values. Variables used for keratoconus detection showed a weak correlation with each other (eg, correlation r=0.245 between RPImin and Kmax, pKPI). KPI was defined by logistic regression and consisted of a Pachymin coefficient of -0.78 (p=0.001), a maximum elevation of back surface coefficient of 0.27 and coefficient of corneal curvature at the zone 3 mm away from the thinnest point on the posterior corneal surface of -12.44 (both pKPI: D-index had a cut-off of 0.4175 (70.6% sensitivity) and Youden Index of 0.606. Cut-off for KPI was -0.78196 (84.7% sensitivity) and a Youden Index of 0.747; both 90% specificity. Keratoconus progression should be defined by evaluating parameters that consider several corneal changes; we suggest D-index and KPI to detect progression. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  17. Progressive posterior cortical dysfunction

    Directory of Open Access Journals (Sweden)

    Fábio Henrique de Gobbi Porto

    Full Text Available Abstract Progressive posterior cortical dysfunction (PPCD is an insidious syndrome characterized by prominent disorders of higher visual processing. It affects both dorsal (occipito-parietal and ventral (occipito-temporal pathways, disturbing visuospatial processing and visual recognition, respectively. We report a case of a 67-year-old woman presenting with progressive impairment of visual functions. Neurologic examination showed agraphia, alexia, hemispatial neglect (left side visual extinction, complete Balint's syndrome and visual agnosia. Magnetic resonance imaging showed circumscribed atrophy involving the bilateral parieto-occipital regions, slightly more predominant to the right . Our aim was to describe a case of this syndrome, to present a video showing the main abnormalities, and to discuss this unusual presentation of dementia. We believe this article can contribute by improving the recognition of PPCD.

  18. Progressive posterior cortical dysfunction

    Science.gov (United States)

    Porto, Fábio Henrique de Gobbi; Machado, Gislaine Cristina Lopes; Morillo, Lilian Schafirovits; Brucki, Sonia Maria Dozzi

    2010-01-01

    Progressive posterior cortical dysfunction (PPCD) is an insidious syndrome characterized by prominent disorders of higher visual processing. It affects both dorsal (occipito-parietal) and ventral (occipito-temporal) pathways, disturbing visuospatial processing and visual recognition, respectively. We report a case of a 67-year-old woman presenting with progressive impairment of visual functions. Neurologic examination showed agraphia, alexia, hemispatial neglect (left side visual extinction), complete Balint’s syndrome and visual agnosia. Magnetic resonance imaging showed circumscribed atrophy involving the bilateral parieto-occipital regions, slightly more predominant to the right. Our aim was to describe a case of this syndrome, to present a video showing the main abnormalities, and to discuss this unusual presentation of dementia. We believe this article can contribute by improving the recognition of PPCD. PMID:29213665

  19. ISABELLE: a progress report

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, H

    1980-01-01

    This paper discusses the ISABELLE project, which has the objective of constructing a high-energy proton colliding beam facility at Brookhaven National Laboratory. The major technical features of the intersecting storage accelerators with their projected performance are described. Application of over 1000 superconducting magnets in the two rings represents the salient characteristic of the machine. The status of the entire project, the technical progress made so far, and difficulties encountered are reviewed.

  20. ISABELLE: a progress report

    International Nuclear Information System (INIS)

    Hahn, H.

    1980-01-01

    This paper discusses the ISABELLE project, which has the objective of constructing a high-energy proton colliding beam facility at Brookhaven National Laboratory. The major technical features of the intersecting storage accelerators with their projected performance are described. Application of over 1000 superconducting magnets in the two rings represents the salient characteristic of the machine. The status of the entire project, the technical progress made so far, and difficulties encountered are reviewed

  1. Progress in optics

    CERN Document Server

    Wolf, Emil

    2009-01-01

    In the fourty-seven years that have gone by since the first volume of Progress in Optics was published, optics has become one of the most dynamic fields of science. The volumes in this series which have appeared up to now contain more than 300 review articles by distinguished research workers, which have become permanent records for many important developments.- Backscattering and Anderson localization of light- Advances in oliton manipulation in optical lattices- Fundamental quantum noise in optical amplification- Invisibility cloaks

  2. Progress in optics

    CERN Document Server

    Wolf, Emil

    2008-01-01

    In the fourty-six years that have gone by since the first volume of Progress in Optics was published, optics has become one of the most dynamic fields of science. The volumes in this series which have appeared up to now contain more than 300 review articles by distinguished research workers, which have become permanent records for many important developments.- Metamaterials- Polarization Techniques- Linear Baisotropic Mediums- Ultrafast Optical Pulses- Quantum Imaging- Point-Spread Funcions- Discrete Wigner Functions

  3. Recent progress in microcalorimetry

    CERN Document Server

    Calvet, E; Skinner, H A

    2013-01-01

    Recent Progress in Microcalorimetry focuses on the methodologies, processes, and approaches involved in microcalorimetry, as well as heat flow, temperature constancy, and chemistry of alumina and cements.The selection first offers information on the different types of calorimeters; measurement of the heat flow between the calorimeter and jacket boundaries by means of a thermoelectric pile; and constructional details of the microcalorimeter. Discussions focus on classification of calorimeters, use of thermoelectric piles as thermometers, correct measurement of heat flow from a calorimeter conta

  4. Clean Energy Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    For the past several years, the IEA and others have been calling for a clean energy revolution to achieve global energy security, economic growth and climate change goals. This report analyses for the first time progress in global clean energy technology deployment against the pathways that are needed to achieve these goals. It provides an overview of technology deployment status, key policy developments and public spending on RDD&D of clean energy technologies.

  5. Progress in nanophotonics 1

    CERN Document Server

    Ohtsu, Motoichi

    2011-01-01

    This book focuses on the recent progress in nanophotonics technology to be used to develop novel nano-optical devices, fabrication technology, and security systems. It begins with a review of the concept of dressed photons and applications to devices, fabrication, and systems; principles and applications. Further topics include: DNA process for quantum dot chain, photon enhanced emission microscopy, near field spectroscopy of metallic nanostructure, self-organized fabrication of composite semiconductor quantum dots, formation of metallic nanostructure, and nanophotonic information systems with

  6. Three year progress report

    International Nuclear Information System (INIS)

    1977-07-01

    Progress is reported on the following studies: x-ray and uv effects in photosynthetic organisms; effects of alcohols and oxygen concentration on transforming DNA; free radical studies; sensitization by metal ions; role of the solvated electron in radiation damage to cells; effectiveness of organic and inorganic compounds in sensitizing bacterial spores to high energy radiation; oxygen effects; radiosensitivity of enzyme systems in Chlorella; and effects of pre-irradiation of solutions on spores

  7. Progressive pseudorheumatoid dysplasia

    International Nuclear Information System (INIS)

    Mampaey, S.; De Schepper, A.; Vanhoenacker, F.; Boven, K.; Hul, W. van

    2000-01-01

    A rare case of progressive pseudorheumatoid dysplasia (PPD) in a 9-year-old girl is presented. Clinically, chronic painless swollen joints, accompanied by progressive motion restriction and progressive walking difficulties, were found. Radiologically, there was enlargement of the epimetaphyseal portions of the large joints, metacarpal heads, and phalanges, and generalized platyspondyly with irregular delineation of the endplates of the vertebral bodies. The radioclinical features at the peripheral joints were originally misdiagnosed as juvenile rheumatoid arthritis (JRA), and the structural spinal abnormalities were neglected and interpreted as Scheuermann's disease. However, the absence of active inflammatory parameters argues against JRA, whereas the low age of onset of the irregularities at the vertebral endplates is an argument against the diagnosis of Scheuermann's disease. The combination of the dysplastic abnormalities of the spine, with platyspondyly and Scheuermann-like lesions at an unusually low age of onset, and radiological features mimicking JRA of the peripheral joints, is the clue to the diagnosis of this rare autosomal-recessive disease. This case is the first to document the MRI features of PPD of the spine. (orig.)

  8. Dicty_cDB: CFH244 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available CF (Link to library) CFH244 (Link to dictyBase) - - - Contig-U16381-1 CFH244F (Link... to Original site) CFH244F 124 - - - - - - Show CFH244 Library CF (Link to library) Clone ID CFH244 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16381-1 Original site URL http://dict...ts) Value N AC115685 |AC115685.1 Dictyostelium discoideum chromosome 2 map 4718821-4752388 strain AX4, compl...ete sequence. 82 2e-29 3 X51892 |X51892.1 Dictyostelium discoideum SP60 gene for spore coat protein. 82 4e-29 2 X52105 |X52105.1 Dict

  9. Dicty_cDB: FC-IC0102 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC-IC (Link to library) FC-IC0102 (Link to dictyBase) - - - Contig-U16527-1 FC-IC01...02F (Link to Original site) FC-IC0102F 434 - - - - - - Show FC-IC0102 Library FC-IC (Link to library) Clone ...ID FC-IC0102 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16527-1 Original site URL http://dict... (bits) Value N AB088483 |AB088483.1 Dictyostelium discoideum gene for gamete and mating-type specific prote...oducing significant alignments: (bits) Value AB088483_1( AB088483 |pid:none) Dictyostelium discoideum gmsA g

  10. Dicty_cDB: SLB690 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available r Dp87... 45 9e-04 AC117267_7( AC117267 |pid:none) Dictyostelium discoideum chromosom... 40 0.037 AY574051_1( AY574051 |pid:none) Ict...SL (Link to library) SLB690 (Link to dictyBase) - - - Contig-U16325-1 SLB690Z (Link... to Original site) - - SLB690Z 481 - - - - Show SLB690 Library SL (Link to library) Clone ID SLB690 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16325-1 Original site URL http://dict...t alignments: (bits) Value N ( AF066071 ) Dictyostelium discoideum SP85 (pspB) gene, comple... 831 0.0 1 ( AC117075 ) Dict

  11. Dicty_cDB: CHD405 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available CH (Link to library) CHD405 (Link to dictyBase) - - - Contig-U15984-1 CHD405E (Link... Clone ID CHD405 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U15984-1 Original site URL http://dict...ts) Value N AC115599 |AC115599.2 Dictyostelium discoideum chromosome 2 map 422909...8-4354721 strain AX4, complete sequence. 42 3e-11 9 AC115598 |AC115598.2 Dictyostelium discoideum chromosome... 2 map 581427-735498 strain AX4, complete sequence. 50 4e-11 11 CK417372 |CK417372.1 AUF_IpInt_56_d19 Intestine cDNA library Ict

  12. Dicty_cDB: SSC474 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available SS (Link to library) SSC474 (Link to dictyBase) - - - Contig-U07719-1 SSC474P (Link... to Original site) SSC474F 368 SSC474Z 238 SSC474P 606 - - Show SSC474 Library SS (Link to library) Clone ID SSC474 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U07719-1 Original site URL http://dict...logy vs DNA Score E Sequences producing significant alignments: (bits) Value N ( AU071762 ) Dictyostelium di...scoideum slug cDNA, clone SSC474. 448 e-121 1 ( AU060185 ) Dictyostelium discoideum slug cDNA, clone SLA535.

  13. Dicty_cDB: CFH809 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available CF (Link to library) CFH809 (Link to dictyBase) - - - Contig-U16381-1 - (Link to Or...iginal site) CFH809F 135 - - - - - - Show CFH809 Library CF (Link to library) Clone ID CFH809 (Link to dicty...Base) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16381-1 Original site URL http://dictycdb.b...ce. 82 2e-29 3 X51892 |X51892.1 Dictyostelium discoideum SP60 gene for spore coat protein. 82 5e-29 2 X52105 |X52105.1 Dict...yostelium discoideum SP60 gene for spore coat protein. 80 9e-27 2 AC116977 |AC116977.2 Dict

  14. Dicty_cDB: VSH207 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VS (Link to library) VSH207 (Link to dictyBase) - - - Contig-U12548-1 VSH207P (Link... to Original site) VSH207F 228 VSH207Z 107 VSH207P 335 - - Show VSH207 Library VS (Link to library) Clone ID VSH207 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U12548-1 Original site URL http://dict...ents: (bits) Value N ( AU267072 ) Dictyostelium discoideum vegetative cDNA clone:VS... 206 2e-58 2 ( AC116982 ) Dict...yostelium discoideum chromosome 2 map 3622643... 206 4e-49 1 ( AU267073 ) Dict

  15. Dicty_cDB: VHK278 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VH (Link to library) VHK278 (Link to dictyBase) - - - Contig-U16260-1 - (Link to Original site) VHK2...78F 533 - - - - - - Show VHK278 Library VH (Link to library) Clone ID VHK278 (Link to dicty...iol.tsukuba.ac.jp/CSM/VH/VHK2-D/VHK278Q.Seq.d/ Representative seq. ID - (Link to ...Original site) Representative DNA sequence >VHK278 (VHK278Q) /CSM/VH/VHK2-D/VHK278Q.Seq.d/ AACTCTCGAGTGCAAAA...BJ427875 ) Dictyostelium discoideum cDNA clone:ddv63k24, 5' ... 997 0.0 1 ( BJ427874 ) Dictyostelium discoideum cDNA clone:ddv63k2

  16. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFC154 (Link to dictyBase) - - - Contig-U16363-1 VFC154Z (Link... to Original site) - - VFC154Z 551 - - - - Show VFC154 Library VF (Link to library) Clone ID VFC154 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16363-1 Original site URL http://dict...s: (bits) Value N U82513 |U82513.1 Dictyostelium discoideum random slug cDNA25 protein (rsc25) mRNA, partial...producing significant alignments: (bits) Value U82513_1( U82513 |pid:none) Dictyostelium discoideum random s

  17. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB489 (Link to dictyBase) - - - Contig-U16382-1 VFB489P (Link... to Original site) VFB489F 178 VFB489Z 501 VFB489P 679 - - Show VFB489 Library VF (Link to library) Clone ID VFB489 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16382-1 Original site URL http://dict...: (bits) Value N AC116986 |AC116986.2 Dictyostelium discoideum chromosome 2 map 2...e cds. 783 0.0 3 AC115579 |AC115579.2 Dictyostelium discoideum chromosome 2 map 4915084-5005461 strain AX4,

  18. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB788 (Link to dictyBase) - - - Contig-U14924-1 VFB788P (Link... to Original site) VFB788F 158 VFB788Z 768 VFB788P 926 - - Show VFB788 Library VF (Link to library) Clone ID VFB788 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U14924-1 Original site URL http://dict... (bits) Value N AC115592 |AC115592.2 Dictyostelium discoideum chromosome 2 map 1-...2_6( AC115592 |pid:none) Dictyostelium discoideum chromosom... 520 e-146 CU459003_2449( CU459003 |pid:none)

  19. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFC129 (Link to dictyBase) - - - Contig-U16543-1 VFC129F (Link... to Original site) VFC129F 276 - - - - - - Show VFC129 Library VF (Link to library) Clone ID VFC129 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16543-1 Original site URL http://dict... vs DNA Score E Sequences producing significant alignments: (bits) Value N M91382 |M91382.1 Dictyostelium di...scoideum thioredoxin (TRX2) mRNA, 5' end. 281 2e-96 3 M91384 |M91384.1 Dictyostelium discoideum thioredoxin

  20. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFC101 (Link to dictyBase) - - - Contig-U16544-1 VFC101Z (Link... to Original site) - - VFC101Z 556 - - - - Show VFC101 Library VF (Link to library) Clone ID VFC101 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16544-1 Original site URL http://dict...t alignments: (bits) Value N AY164994 |AY164994.1 Dictyostelium discoideum RTNLC (RTNLC) mRNA, complete cds.... 969 0.0 2 AY164656 |AY164656.1 Dictyostelium discoideum RTNLC (RTNLC) gene, complete cds. 565 0.0 3 AL71386

  1. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB645 (Link to dictyBase) - - - Contig-U16382-1 VFB645P (Link... to Original site) VFB645F 619 VFB645Z 413 VFB645P 1032 - - Show VFB645 Library VF (Link to library) Clone ID VFB645 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16382-1 Original site URL http://dict...mology vs DNA Score E Sequences producing significant alignments: (bits) Value N X03281 |X03281.1 Dictyostel...ium discoideum gene for actin A8. 1174 0.0 2 AC116957 |AC116957.2 Dictyostelium discoideum chromosome 2 map

  2. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFC187 (Link to dictyBase) - - - Contig-U12289-1 VFC187P (Link... to Original site) VFC187F 411 VFC187Z 678 VFC187P 1089 - - Show VFC187 Library VF (Link to library) Clone ID VFC187 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U12289-1 Original site URL http://dict... N AC117176 |AC117176.2 Dictyostelium discoideum chromosome 2 map 5018074-5200947... strain AX4, complete sequence. 36 0.008 12 AC114263 |AC114263.2 Dictyostelium discoideum chromosome 2 map 2

  3. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB837 (Link to dictyBase) - - - Contig-U14985-1 VFB837P (Link... to Original site) VFB837F 606 VFB837Z 689 VFB837P 1295 - - Show VFB837 Library VF (Link to library) Clone ID VFB837 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U14985-1 Original site URL http://dict... 13 AC116986 |AC116986.2 Dictyostelium discoideum chromosome 2 map 2234041-256737...0 strain AX4, complete sequence. 38 2e-05 15 AC116984 |AC116984.2 Dictyostelium discoideum chromosome 2 map

  4. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB733 (Link to dictyBase) - - - Contig-U16279-1 VFB733P (Link... to Original site) VFB733F 608 VFB733Z 663 VFB733P 1271 - - Show VFB733 Library VF (Link to library) Clone ID VFB733 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16279-1 Original site URL http://dict...es producing significant alignments: (bits) Value N U23957 |U23957.1 Dictyostelium discoideum P52D mRNA, com...15 e-114 U23957_1( U23957 |pid:none) Dictyostelium discoideum P52D mRNA, co... 41

  5. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB862 (Link to dictyBase) - - - Contig-U16311-1 VFB862P (Link... to Original site) VFB862F 624 VFB862Z 720 VFB862P 1344 - - Show VFB862 Library VF (Link to library) Clone ID VFB862 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16311-1 Original site URL http://dict...s) Value N U72746 |U72746.1 Dictyostelium discoideum cysteine proteinase (cprG) m...RNA, complete cds. 1209 0.0 5 U72745 |U72745.1 Dictyostelium discoideum cysteine proteinase (cprF) mRNA, com

  6. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFC138 (Link to dictyBase) - - - Contig-U15456-1 VFC138P (Link... to Original site) VFC138F 411 VFC138Z 440 VFC138P 851 - - Show VFC138 Library VF (Link to library) Clone ID VFC138 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U15456-1 Original site URL http://dict...ducing significant alignments: (bits) Value N Y16962 |Y16962.1 Dictyostelium discoideum mRNA for cathepsin D.... 815 0.0 4 AJ243946 |AJ243946.1 Dictyostelium discoideum ctsD gene for cathepsin D, exons 1 to 2. 815 0.0 5

  7. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB662 (Link to dictyBase) - - - Contig-U15118-1 VFB662E (Link...) Clone ID VFB662 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U15118-1 Ori... significant alignments: (bits) Value N AF039211 |AF039211.1 Dictyostelium discoideum ADP/ATP translocase mR...NA, complete cds. 1011 0.0 2 AF100676 |AF100676.1 Dictyostelium discoideum ADP/ATP translocase gene, complet...drial 4.0 %: extracellular, including cell wall 4.0 %: vacuolar 4.0 %: vesicles of secretory system >> predict

  8. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB769 (Link to dictyBase) - - - Contig-U15456-1 VFB769P (Link... to Original site) VFB769F 625 VFB769Z 690 VFB769P 1315 - - Show VFB769 Library VF (Link to library) Clone ID VFB769 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U15456-1 Original site URL http://dict...roducing significant alignments: (bits) Value N Y16962 |Y16962.1 Dictyostelium discoideum mRNA for cathepsin... D. 1257 0.0 3 AJ243946 |AJ243946.1 Dictyostelium discoideum ctsD gene for cathep

  9. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB843 (Link to dictyBase) - - - Contig-U15729-1 VFB843F (Link... to Original site) VFB843F 566 - - - - - - Show VFB843 Library VF (Link to library) Clone ID VFB843 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U15729-1 Original site URL http://dict...roducing significant alignments: (bits) Value N U64830 |U64830.1 Dictyostelium discoideum AX2 protein tyrosi...ne kinase gene, complete cds. 1114 0.0 1 U01064 |U01064.1 Dictyostelium discoideum AX2 protein tyrosine kina

  10. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB741 (Link to dictyBase) - - - Contig-U16382-1 VFB741P (Link... to Original site) VFB741F 545 VFB741Z 675 VFB741P 1220 - - Show VFB741 Library VF (Link to library) Clone ID VFB741 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16382-1 Original site URL http://dict...bits) Value N X03281 |X03281.1 Dictyostelium discoideum gene for actin A8. 1166 0....0 2 AC116957 |AC116957.2 Dictyostelium discoideum chromosome 2 map 1685067-2090751 strain AX4, complete seq

  11. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB829 (Link to dictyBase) - - - - VFB829Z (Link to Original s...ite) - - VFB829Z 600 - - - - Show VFB829 Library VF (Link to library) Clone ID VFB829 (Link to dictyBase) Atlas ID - NBRP ID - dict...yBase ID - Link to Contig - Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/... long chain poly-unsaturated fatty acids. 1189 0.0 1 AB029311 |AB029311.1 Dictyostelium discoideum Dd des5 g...ene for fatty acid desaturase, complete cds. 823 0.0 2 AB022097 |AB022097.1 Dictyostelium discoideum mRNA fo

  12. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB710 (Link to dictyBase) - - - Contig-U16382-1 VFB710P (Link... to Original site) VFB710F 123 VFB710Z 689 VFB710P 812 - - Show VFB710 Library VF (Link to library) Clone ID VFB710 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16382-1 Original site URL http://dict... significant alignments: (bits) Value N X03281 |X03281.1 Dictyostelium discoideum... gene for actin A8. 1308 0.0 2 AC116957 |AC116957.2 Dictyostelium discoideum chromosome 2 map 1685067-209075

  13. Dicty_cDB: Contig-U16423-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 65776 ) Dictyostelium discoideum cDNA clone:ddc36f16, 5' ... 74 3e-22 2 ( FG288312 ) 1108793266221 New World... 4e-19 3 ( FI057728 ) CHO_OF6610xh18r1.ab1 CHO_OF6 Nicotiana tabacum ge... 64 6e-19 3 ( FG286148 ) 1108770713996 New World...9c24,... 90 7e-18 3 ( CJ411606 ) Molgula tectiformis cDNA, larva clone:mtlv010d03,... 90 7e-18 3 ( FG288831 ) 1108793284713 New World...e-13 2 ( FG299437 ) 1108793335742 New World Screwworm Larvae 9387 EST... 80 2e-13 2 ( DV613229 ) EST1216225 ...BJ379331 ) Dictyostelium discoideum cDNA clone:ddc34c13, 3' ... 90 5e-13 1 ( FG300027 ) 1108793358668 New World

  14. Dicty_cDB: SLC455 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available SL (Link to library) SLC455 (Link to dictyBase) - - - Contig-U16584-1 SLC455Z (Link... to Original site) - - SLC455Z 379 - - - - Show SLC455 Library SL (Link to library) Clone ID SLC455 (Link to...ycdb.biol.tsukuba.ac.jp/CSM/SL/SLC4-C/SLC455Q.Seq.d/ Representative seq. ID SLC45...5Z (Link to Original site) Representative DNA sequence >SLC455 (SLC455Q) /CSM/SL/SLC4-C/SLC455Q.Seq.d/ XXXXX...57 ) Dictyostelium discoideum slug cDNA, clone SLC469. 468 e-177 3 ( AU034549 ) Dictyostelium discoideum slug cDNA, clone SLC4

  15. ARGUS progress report 1982

    International Nuclear Information System (INIS)

    Darden, C.W. III.

    1982-01-01

    On September 7th, 1982, following four years of planning and construction, the magnetic solenoid detector ARGUS was moved into one of the two interaction regions of the electron-positron storage ring DORIS. A month later the ring started delivering luminosity for physics research, specifically, the study of the formation and decay of members of the Upsilon family of mesons. These mesons are bound states, b anti b, of the heaviest of the five known quarks and therefore of considerable interest. This report describes the progress made during the year from March 1982 to March 1983 with emphasis on the experience gained during the first running period

  16. HSX progress report

    International Nuclear Information System (INIS)

    1994-01-01

    Brief statements on the progress of the design and construction of the HSX experiment are reported. Topics covered include the modular and auxiliary coil systems, the coil support structure, vacuum vessel, the ECH system, the magnet power supply and site. The proposed budget for Year 2 (August 1, 1994 through July 31, 1995) is presented. The effects of a flat funding profile (based on Year 2 budget level of $1137K) on out-years and the HSX project schedule are discussed. The stretching out of the program to accommodate the reduced funding profile should result in only a slight delay in HSX operations

  17. Progress in optics

    CERN Document Server

    Wolf, Emil

    1977-01-01

    In the thirty-seven years that have gone by since the first volume of Progress in Optics was published, optics has become one of the most dynamic fields of science. At the time of inception of this series, the first lasers were only just becoming operational, holography was in its infancy, subjects such as fiber optics, integrated optics and optoelectronics did not exist and quantum optics was the domain of only a few physicists. The term photonics had not yet been coined. Today these fields are flourishing and have become areas of specialisation for many science and engineering students and n

  18. [Research progress on fascioliasis].

    Science.gov (United States)

    Liu, Qian; Cheng, Na; Zhou, Yan; Xu, Xue-Nian

    2013-06-01

    Fascioliasis is an important zoonosis caused by Fasciola spp. It can cause pathological damages to human liver and gallbladder, as well as economic loss in animal husbandry. Fascioliasis can be easily misdiagnosed with other hepatobiliary diseases. The appearance of resistance to triclabendazole is an issue problem for fascioliasis control. Therefore, research for better diagnostic methods, effective drugs and vaccines become to the focus of fascioliasis control. This article summarizes the progress on epidemiological status, diagnostic method, therapy, drug resistance, vaccine and omics of fascioliasis.

  19. Mathieu Progressive Waves

    Science.gov (United States)

    Andrei, B. Utkin

    2011-10-01

    A new family of exact solutions to the wave equation representing relatively undistorted progressive waves is constructed using separation of variables in the elliptic cylindrical coordinates and one of the Bateman transforms. The general form of this Bateman transform in an orthogonal curvilinear cylindrical coordinate system is discussed and a specific problem of physical feasibility of the obtained solutions, connected with their dependence on the cyclic coordinate, is addressed. The limiting case of zero eccentricity, in which the elliptic cylindrical coordinates turn into their circular cylindrical counterparts, is shown to correspond to the focused wave modes of the Bessel-Gauss type.

  20. Mathieu Progressive Waves

    International Nuclear Information System (INIS)

    Utkin, Andrei B.

    2011-01-01

    A new family of exact solutions to the wave equation representing relatively undistorted progressive waves is constructed using separation of variables in the elliptic cylindrical coordinates and one of the Bateman transforms. The general form of this Bateman transform in an orthogonal curvilinear cylindrical coordinate system is discussed and a specific problem of physical feasibility of the obtained solutions, connected with their dependence on the cyclic coordinate, is addressed. The limiting case of zero eccentricity, in which the elliptic cylindrical coordinates turn into their circular cylindrical counterparts, is shown to correspond to the focused wave modes of the Bessel-Gauss type. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  1. TASCC Division progress report

    International Nuclear Information System (INIS)

    Hardy, J.C.

    1992-10-01

    The TASCC (Tandem Accelerator-Superconducting Cyclotron) facility is devoted to developing and providing beams for an experimental program of basic nuclear research. Beam was on target for 2901 hours during the period of interest. The cyclotron provided beam for 524 hours, and tandem beams were used for a total of 3940 hours. The most exciting experimental result was the first evidence of a rotational band with the characteristics of hyperdeformation: a ridge-valley structure in 152 Dy. This progress report details experimental results and instrumentation and facility development over the period. (L.L.) (refs., tabs., figs.)

  2. Progress in optics

    CERN Document Server

    Wolf, Emil

    2006-01-01

    In the thirty-seven years that have gone by since the first volume of Progress in Optics was published, optics has become one of the most dynamic fields of science. At the time of inception of this series, the first lasers were only just becoming operational, holography was in its infancy, subjects such as fiber optics, integrated optics and optoelectronics did not exist and quantum optics was the domain of only a few physicists. The term photonics had not yet been coined. Today these fields are flourishing and have become areas of specialisation for many science and engineering students and n

  3. Progress in nanophotonics 1

    Energy Technology Data Exchange (ETDEWEB)

    Ohtsu, Motoichi (ed.) [Tokyo Univ. (Japan). Graduate School of Engineering

    2011-07-01

    This book focuses on the recent progress in nanophotonics technology to be used to develop novel nano-optical devices, fabrication technology, and security systems. It begins with a review of the concept of dressed photons and applications to devices, fabrication, and systems; principles and applications. Further topics include: DNA process for quantum dot chain, photon enhanced emission microscopy, near field spectroscopy of metallic nanostructure, self-organized fabrication of composite semiconductor quantum dots, formation of metallic nanostructure, and nanophotonic information systems with security. These topics are reviewed by seven leading scientists. This overview is a variable resource for engineers and scientists working in the field of nanophotonics. (orig.)

  4. Dicty_cDB: SLA508 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available e-101 SLD569 (SLD569Q) /CSM/SL/SLD5-C/SLD569Q.Seq.d/ 250 1e-65 SLD492 (SLD492Q) /CSM/SL/SLD4-D/SLD492...oideum slug cDNA, clone SLD569. 250 2e-62 1 ( AU052538 ) Dictyostelium discoideum slug cDNA, clone SLD492. 7

  5. Dicty_cDB: [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFB595 (Link to dictyBase) - - - Contig-U09552-1 VFB595E (Link...) Clone ID VFB595 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U09552-1 Ori...KLLKSDNWISTCQNLIQEYEPQ IIAVVEGFMAPSELCQKIKFCSSSSSTNDFDFIGSSTTDCEICTFISGYAENFLEENKTL EDIIKVVDDFCKILPAAYKTDCVA...A: VEGSGECLVCEFISEKIVTYLEANQTETQILQYLDNDCKLLKSDNWISTCQNLIQEYEPQ IIAVVEGFMAPSELCQKIKFCSSSSSTNDFDFIGSSTTDCEICT... Sequences producing significant alignments: (bits) Value N U66367 |U66367.1 Dictyostelium discoideum SapA (

  6. Dicty_cDB: CFG115 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available CF (Link to library) CFG115 (Link to dictyBase) - - - Contig-U03237-1 CFG115E (Link...) Clone ID CFG115 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U03237-1 Ori...k*NNMNGFLKSQLENKTNATTTTTTRYCNNDESCNDENLCTN EMCDPVIGCIYENISCDDDNGCTKDFCDPLTGCFHKRVVCDDNDKCTDNICNPETGTCSF RRRICT...TTTRYCNNDESCNDENLCTN EMCDPVIGCIYENISCDDDNGCTKDFCDPLTGCFHKRVVCDDNDKCTDNICNPETGTCSF RRRICTDNNDCTMDWCNQLTGECVYQ...ng significant alignments: (bits) Value N AC116984 |AC116984.2 Dictyostelium discoideum chromosome 2 map 256

  7. Dicty_cDB: VFH641 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VF (Link to library) VFH641 (Link to dictyBase) - - - Contig-U16151-1 VFH641E (Link... Clone ID VFH641 (Link to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U16151-1 Original site URL http://dict...KLLGVQTQAKQTRATWKIVVGDGAGAVTFKLATNGGTTEGDFTTTLTSKVLS GSDPKEVGTYYMDVTVPTGTTCTGTNGICT...KLLGVQTQAKQTRATWKIVVGDGAGAVTFKLATNGGTTEGDFTTTLTSKVLS GSDPKEVGTYYMDVTVPTGTTCTGTNGICT...nificant alignments: (bits) Value N AC116984 |AC116984.2 Dictyostelium discoideum

  8. 3' : 5'-Cyclic AMP-dependent 3'

    NARCIS (Netherlands)

    Mato, José M.; Krens, Frans A.; Haastert, Peter J.M. van; Konijn, Theo M.

    1977-01-01

    Suspensions of 3':5'-cyclic AMP (cAMP)-sensitive cells of Dictyostelium discoideum responded to a cAMP pulse with increased 3':5'-cyclic GMP (cGMP) levels. Under the assay conditions used (2 × 10^8 cells per ml in 10 mM phosphate buffer, pH 6.0) cAMP (5 × 10-8 M final concentration) increased cGMP

  9. Dicty_cDB: FC-AM13 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available in (NS35) gene, complete cds. 52 0.006 1 AB022770 |AB022770.1 Human rotavirus mRNA for NSP2, complete cds. 5...9.2 Dictyostelium discoideum chromosome 2 map 4229098-4354721 strain AX4, complete sequence. 34 0.004 7 X57944 |X57944.1 Human rotavi...rus segment 7 gp33 gene. 52 0.006 1 L04534 |L04534.1 Rotavirus non-structural prote

  10. Progressive pseudorheumatoid dysplasia misdiagnosed as ...

    African Journals Online (AJOL)

    Progressive pseudorheumatoid dysplasia misdiagnosed as seronegative juvenile idiopathic arthritis. Ozgur Taspinar, Fatih Kelesoglu, Yasar Keskin, Murat Uludag. Abstract. Background: Progressive pseudorheumatoid dysplasia (PPD) is a rare spondylo- epi-metaphyseal dysplasia (SEMD). It can be confused with juvenile ...

  11. Slowly progressive fluent aphasia

    International Nuclear Information System (INIS)

    Sakurai, Yasuhisa; Momose, Toshimitsu; Watanabe, Toshiaki; Ishikawa, Takashi; Iwata, Makoto; Bando, Mitsuaki.

    1991-01-01

    Three patients with slowly progressive fluent aphasia are reported. One of the patients presented with memory disturbance. They were characterized clinically by having selective deficits in vocabulary, which resulted in impairment of confrontation naming, and auditory comprehension. MRI showed an atrophy not only in the left temporal lobe (including the superior, middle and inferior temporal gyri), hippocampus, parahippocampual gyrus, and fusiform gyrus, but also in the left parietal lobe. I-123 IMP SPECT and F-18 FDG PET were used to determine regional cerebral blood flow and regional cerebral metabolic rate, respectively. In addition to the decreased tracer uptake in the left temporal and/or parietal lobe, a decreased uptake was seen in the bilateral basal ganglia, the inner side of the temporal lobe (including the bilateral hippocampus), the right anterior temporal lobe, and the left thalamus. These findings may deny the previous thought that lesions are localized in slowly progressive fluent aphasia. Furthermore, noticeable difficulty in naming, i.e., patients unable to recognize the right answer, are considered attributable to widespread lesions from the whole left temporal lobe, including the hippocampus, to the right temporal lobe. (N.K.)

  12. Progress in computational toxicology.

    Science.gov (United States)

    Ekins, Sean

    2014-01-01

    Computational methods have been widely applied to toxicology across pharmaceutical, consumer product and environmental fields over the past decade. Progress in computational toxicology is now reviewed. A literature review was performed on computational models for hepatotoxicity (e.g. for drug-induced liver injury (DILI)), cardiotoxicity, renal toxicity and genotoxicity. In addition various publications have been highlighted that use machine learning methods. Several computational toxicology model datasets from past publications were used to compare Bayesian and Support Vector Machine (SVM) learning methods. The increasing amounts of data for defined toxicology endpoints have enabled machine learning models that have been increasingly used for predictions. It is shown that across many different models Bayesian and SVM perform similarly based on cross validation data. Considerable progress has been made in computational toxicology in a decade in both model development and availability of larger scale or 'big data' models. The future efforts in toxicology data generation will likely provide us with hundreds of thousands of compounds that are readily accessible for machine learning models. These models will cover relevant chemistry space for pharmaceutical, consumer product and environmental applications. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Annual progress report

    International Nuclear Information System (INIS)

    Russek, A.

    1975-06-01

    Progress has been made in calculation of cross-sections for dielectronic and radiative recombination when hot electrons are incident on partially stripped impurity ions. Calculations were completed for the cases of 1 keV and 10 keV electrons incident on ions of arbitrary Z with ionization state consistent with a 1 keV plasma temperature. It was found that dielectronic recombination dominates radiative recombination by a factor of 100 at 1 keV incident electron energy to a factor of 1000 at 10 keV incident electron energy. The work is now being extended to other plasma temperatures and is being improved by more accurate calculation of the matrix elements involved. Progress was also made in the calculation of accurate bremsstrahlung and higher order radiative processes which also occur when hot electrons are incident on partially stripped impurity ions. Formal expressions for the matrix elements have been obtained for cross-sections in a fully relativistic partial wave analysis for bremsstrahlung radiation both with and without electron excitation of the target ion. Final evaluation now awaits the evaluation of the relativistic radial integrals involved in these matrix elements. (U.S.)

  14. Ghrelin and cancer progression.

    Science.gov (United States)

    Lin, Tsung-Chieh; Hsiao, Michael

    2017-08-01

    Ghrelin is a small peptide with 28 amino acids, and has been characterized as the ligand of the growth hormone secretagogue receptor (GHSR). In addition to its original function in stimulating pituitary growth hormone release, ghrelin is multifunctional and plays a role in the regulation of energy balance, gastric acid release, appetite, insulin secretion, gastric motility and the turnover of gastric and intestinal mucosa. The discovery of ghrelin and GHSR expression beyond normal tissues suggests its role other than physiological function. Emerging evidences have revealed ghrelin's function in regulating several processes related to cancer progression, especially in metastasis and proliferation. We further show the relative GHRL and GHSR expression in pan-cancers from The Cancer Genome Atlas (TCGA), suggesting the potential pathological role of the axis in cancers. This review focuses on ghrelin's biological function in cancer progression, and reveals its clinical significance especially the impact on cancer patient outcome. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Annual progress report 1980

    International Nuclear Information System (INIS)

    1981-01-01

    The technical support activities of the IPSN to competent administrations in 1980 has been marked: namely by the authorizations of divergence for 9 units EdF-PWR of 900 MW, the authorization project of creation and extension of reprocessing plant of COGEMA at the Hague UP 2 -800 and the authorization of starting up of the third unit of production of the EURODIF enrichment plant at Tricastin. On the other hand, IPSN has participated at the elaboration of a certain number of legislative and regulation texts relative to the control of nuclear matter, to radioprotection standards and to criteria of safety. For the safety of breeder, the test made at CABRI pile, in the international research program has given confirmation of the validity of theoretical models used in accidents calculations, hypothetical accidents which has allowed to reactualize safety criteria which have to be used for the development of this type of reactor. In worker radioprotection the results obtained in laboratory on the effect of radon, the progress made in personal dosimetry and the action of radioprotection undertaken in uranium mines constitutes a coherent effort. The deep drilling in granit (1000 m) and the experimental associated program which has finished the indispensable scientific data for the future policy in matter of storage of radioactives wastes. IPSN has contributed to progress made in the rules of exploitation of reactors, in the definition of wastes containment -specially at the output of reprocessing plant- in handling machines in hazardeous areas and in the study of environment [fr

  16. Association for Progressive Communication : Institutional ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Monitoring Progress Toward the Information Society : Digital Divide Index. Orbicom's Digital Divide Index is a rigorous statistical tool for benchmarking access to and use of information and communication technologies (ICT), and monitoring progress toward the... View moreMonitoring Progress Toward the Information ...

  17. Progress report 1998

    International Nuclear Information System (INIS)

    1999-01-01

    The O.P.R.I. is in charge of environmental general surveillance and follow-up of natural exposures; To monitor the nuclear installations, it carries out samples campaigns. The technical follow-up of medical installations concerns it too. The workers radiation protection as well as the public protection are in its attributions. We find in particular, three sanitary studies: about the North Cotentin, (the question of excess of leukemia or not, and due or not to the facility of La hague) Nogent-sur-Marne (the case of a nursery school built on a old factory using radium), and the situation of populations living in French Polynesia, areas that have worried the public with alarmist announcements published in newspapers. All the results relative to the radiations measurements for 1998 appear in this progress report. (N.C.)

  18. Progress report 1981 - 1983

    International Nuclear Information System (INIS)

    Eder, G.; Rauch, H.; Balcar, E.; Buchtela, K.; Schwertfuehrer, W.; Vana, N.

    1984-06-01

    This progress report describes the research activities of the Atom-institute of the Austrian Universities of the period 1981-1983. The chapter headings are: (1) Electron- and X-ray physics, thermoluminescence and archeometry. (2) Nuclear physics. (3) Nuclear techniques, electronics and EDP. (4) Neutron- and solid state physics with neutron scattering, low temperature physics, theoretical solid state physics and preparation technique. (5) Radiation chemistry. (6) Radiation protection and dosimetry. Each chapter gives a comprimated overview about the research work done in the described period, illustrated by diagrams and tables, a comprehensive list of publications, each citation provided with an (mostly English) Abstract and a comprehensive list of thesis, which are completed or under preparation in the corresponding working group. Additional chapters give lists of educational work, verbal presentation, cooperations with other institutions and personnel. An annex of photos gives an additional impression of the institute. (A.N.)

  19. Progressing batch hydrolysis process

    Science.gov (United States)

    Wright, J.D.

    1985-01-10

    A progressive batch hydrolysis process is disclosed for producing sugar from a lignocellulosic feedstock. It comprises passing a stream of dilute acid serially through a plurality of percolation hydrolysis reactors charged with feed stock, at a flow rate, temperature and pressure sufficient to substantially convert all the cellulose component of the feed stock to glucose. The cooled dilute acid stream containing glucose, after exiting the last percolation hydrolysis reactor, serially fed through a plurality of pre-hydrolysis percolation reactors, charged with said feedstock, at a flow rate, temperature and pressure sufficient to substantially convert all the hemicellulose component of said feedstock to glucose. The dilute acid stream containing glucose is cooled after it exits the last prehydrolysis reactor.

  20. Progressive amusia and aprosody.

    Science.gov (United States)

    Confavreux, C; Croisile, B; Garassus, P; Aimard, G; Trillet, M

    1992-09-01

    We report a case of slowly progressive amusia and aprosody in association with orofacial and eyelid apraxias. The patient was independent in daily living activities. Insight, judgment, and behavior were intact. Her language was normal, and she demonstrated no limb, dressing, or constructional apraxia. She had no prosopagnosia, no visuospatial disturbances, and no memory impairment. Imaging studies (computed tomography, magnetic resonance imaging, single photon emission computed tomography) indicated a selective disorder of the right frontal and temporal regions. Review of the literature shows an increasing number of reports of this degenerative syndrome affecting the left dominant hemisphere and language areas, whereas cases of the syndrome affecting the right hemisphere are rare. To our knowledge, this is the first case in which aprosody and amusia were associated with a focal cortical degeneration.

  1. 1985. Progress annual report

    International Nuclear Information System (INIS)

    1986-06-01

    Tore Supra construction has been vigorously continued. The whole cryogenic system has been entirely delivered. On TFR priority has been given to electron cyclotron resonance heating; but also neutral heating mechanisms, pellet injection, plasma-wall interaction in the presence of pumped limiter, impurity transport and plasma turbulence have been studied and progress on diagnostics have been made. On Petula, with lower hybrid wave, the numerous results on ion heating, current drive, plasma stability in the presence of non-inductive current and on Tore Supra technical problems are important. At last, theoretical and numerical results are concerned with plasma equilibrium macroscopic evolution of plasma, RF heating, plasma instabilities, magnetic islands, turbulence, transport coefficients and spectroscopy [fr

  2. Vivitron - Progress report 1990

    International Nuclear Information System (INIS)

    1991-01-01

    The 1990 activity report of the Strasbourg Nuclear Research, concerning the Vivitron project, is presented. After having mounted all the Van de Graaff elements of the Vivitron needed for the generator tests, the tank was closed in July 1990. It was then put under vacuum, leaks were searched for and repaired. Voltage tests started in December and a voltage of 17.6 MV was reached in February. Modifications on the charging system and to improvement of the column protection against sparks are necessary before the voltage tests can be carried on. Great progress has been made in the setting up of the new Vivitron injector and analysing magnet. In this report are included the description of project different development steps, the Vivitron budget and the list of publications, congress contributions and internal reports. 18 figs

  3. Progressive brain compression

    International Nuclear Information System (INIS)

    Thuomas, K.AA.; Inst. of Surgical Research, National Hospital, Oslo; Vlajkovic, S.; Inst. of Surgical Research, National Hospital, Oslo; Ganz, J.C.; Inst. of Surgical Research, National Hospital, Oslo; Nilsson, P.; Inst. of Surgical Research, National Hospital, Oslo; Bergstroem, K.; Inst. of Surgical Research, National Hospital, Oslo; Ponten, U.; Inst. of Surgical Research, National Hospital, Oslo; Zwetnow, N.N.; Inst. of Surgical Research, National Hospital, Oslo

    1993-01-01

    Continuous recording of vital physiological variables and sequential MR imaging were performed simultaneously during continuous expansion of an epidural rubber balloon over the left hemisphere in anaesthetised dogs. Balloon expansion led to a progressive and slgithly nonlinear rise in intracranial CSF pressures and a full in local perfusion pressures. Changes in systemic arterial pressure, pulse rate, and respiration rate usually appeared at a balloon volume of 4% to 5% of the intracranial volume (reaction volume), together with a marked transtentorial pressure gradient and MR imaging changes consistent with tentorial herniation. Respiratory arrest occurred at a balloon volume of approximately 10% of the intracranial volume (apnoea volume), which was associated with occulsion of the cisterna magna, consistent with some degree of foramen magnum herniation. Increase in tissue water was observed beginning at approximately the reaction volume, presumably due to ischaemic oedema, due to the fall in perfusion pressures. (orig.)

  4. Muon collider progress

    Energy Technology Data Exchange (ETDEWEB)

    Noble, Robert J. FNAL

    1998-08-01

    Recent progress in the study of muon colliders is presented. An international collaboration consisting of over 100 individuals is involved in calculations and experiments to demonstrate the feasibility of this new type of lepton collider. Theoretical efforts are now concentrated on low-energy colliders in the 100 to 500 GeV center-of-mass energy range. Credible machine designs are emerging for much of a hypothetical complex from proton source to the final collider. Ionization cooling has been the most difficult part of the concept, and more powerful simulation tools are now in place to develop workable schemes. A collaboration proposal for a muon cooling experiment has been presented to the Fermilab Physics Advisory Committee, and a proposal for a targetry and pion collection channel experiment at Brookhaven National Laboratory is in preparation. Initial proton bunching and space-charge compensation experiments at existing hadron facilities have occurred to demonstrate proton driver feasibility.

  5. Progress in nanophotonics 3

    CERN Document Server

    Yatsui, Takashi

    2015-01-01

    This book focuses on the recent progress in nanophotonics technology to be used to develop novel nano-optical devices, fabrication technology and advanced systems. It reviews light-emitting diodes and lasers made of silicon bulk crystals in which the light emission principle is based on dressed-photon-phonons. Further topics include: theoretical studies of optoelectronic properties of molecular condensates for organic solar cells and light-emitting devices, the basics of topological light beams together with their important properties for laser spectroscopy, spatially localized modes emerging in nonlinear discrete dynamic systems and theoretical methods to explore the dynamics of nanoparticles by the light-induced force of tailored light fields under thermal fluctuations. These topics are reviewed by leading scientists. This overview is a variable resource for engineers and scientists working in the field of nanophotonics.

  6. Progress in nanophotonics 4

    CERN Document Server

    Yatsui, Takashi

    2017-01-01

    This book presents the recent progress in the field of nanophotonics. It contains review-like chapters focusing on various but mutually related topics in nanophotonics written by the world’s leading scientists. Following the elaboration of the idea of nanophotonics, much theoretical and experimental work has been carried out, and several novel photonic devices, high-resolution fabrication, highly efficient energy conversion, and novel information processing have been developed in these years. Novel theoretical models describing the nanometric light-matter interaction, nonequilibrium statistical mechanical models for photon breeding processes and near-field‐assisted chemical reactions as well as light‐matter interaction are also explained in this book. It describes dressed photon technology and its applications, including implementation of nanophotonic devices and systems, fabrication methods and performance characteristics of ultrathin, ultraflexible organic light‐emitting diodes, organic solar cells ...

  7. Dynamically prioritized progressive transmission

    Science.gov (United States)

    Blanford, Ronald

    1992-04-01

    Retrieval of image data from a centralized database may be subject to bandwidth limitations, whether due to a low-bandwidth communications link or to contention from simultaneous accesses over a high-bandwidth link. Progressive transmission can alleviate this problem by encoding image data so that any prefix of the data stream approximates the complete image at a coarse level of resolution. The longer the prefix, the finer the resolution. In many cases, as little at 1 percent of the image data may be sufficient to decide whether to discard the image, to permit the retrieval to continue, or to restrict retrieval to a subsection of the image. Our approach treats resolution not as a fixed attribute of the image, but rather as a resource which may be allocated to portions of the image at the direction of a user-specified priority function. The default priority function minimizes error by allocating more resolution to regions of high variance. The user may also point to regions of interest requesting priority transmission. More advanced target recognition strategies may be incorporated at the user's discretion. Multispectral imagery is supported. The user engineering implications are profounded. There is immediate response to a query that might otherwise take minutes to complete. The data is transmitted in small increments so that no single user dominates the communications bandwidth. The user-directed improvement means that bandwidth is focused on interesting information. The user may continue working with the first coarse approximations while further image data is still arriving. The algorithm has been implemented in C on Sun, Silicon Graphics, and NeXT workstations, and in Lisp on a Symbolics. Transmission speeds reach as high as 60,000 baud using a Sparc or 68040 processor when storing data to memory; somewhat less if also updating a graphical display. The memory requirements are roughly five bytes per image pixel. Both computational and memory costs may be reduced

  8. IPY Progress and Prospects

    Science.gov (United States)

    Carlson, D.

    2008-12-01

    We can summarize the IPY goals as: (a) make major advances in polar knowledge and understanding; (b) leave a legacy of new or enhanced observational systems, facilities and infrastructure; (c) excite a new generation of polar scientists and engineers, and (d) elicit exceptional interest and participation from polar residents, schoolchildren, the general public, and decision-makers, worldwide. This talk reports on the progress and prospects in each of those areas from an overall international view; separate talks will describe details of future researcher and the IPY outreach efforts. To achieve major advances in knowledge, IPY has entrained the intellectual resources of thousands of scientists, many more than expected, often from 'non- polar' nations, and representing an unprecedented breadth of scientific specialties; integration of those efforts across disciplines to achieve integrated system-level understanding remains a substantial challenge. Many national and international organizations prepare plans to sustain new and improved observational systems, but clear outcomes and the necessary resources remain elusive. International outreach networks gradually build breadth and strength, largely through IPY Polar Science Days and other internationally- coordinated IPY events. A new Association of Polar Early Career Scientists (APECS) devotes talent and energy to shaping the future of polar research. These activities and networks may, with time and with continued international coordination, achieve an exceptional level of interest and participation. In all areas, much work remains.

  9. CERN: LHC progress

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    The push for CERN's next major project, the LHC proton collider to be built in the 27-kilometre LEP tunnel, is advancing on a wide front. For the machine itself, there has been considerable progress in the detailed design. While the main thrust is for proton-proton collisions, heavy ions are also on the LHC collision menu. On the experimental side, proposals are coming into sharper focus. For the machine, the main aim is for the highest possible proton collision energies and collision rates in the confines of the existing LEP tunnel, and the original base design looked to achieve these goals in three collision regions. Early discussions on the experimental programme quickly established that the most probable configuration would have two collision regions rather than three. This, combined with hints that the electronics of several detectors would have to handle several bunch crossings at a time, raised the question whether the originally specified bunch spacing of 15 ns was still optimal

  10. Progress in neuromorphic photonics

    Science.gov (United States)

    Ferreira de Lima, Thomas; Shastri, Bhavin J.; Tait, Alexander N.; Nahmias, Mitchell A.; Prucnal, Paul R.

    2017-03-01

    As society's appetite for information continues to grow, so does our need to process this information with increasing speed and versatility. Many believe that the one-size-fits-all solution of digital electronics is becoming a limiting factor in certain areas such as data links, cognitive radio, and ultrafast control. Analog photonic devices have found relatively simple signal processing niches where electronics can no longer provide sufficient speed and reconfigurability. Recently, the landscape for commercially manufacturable photonic chips has been changing rapidly and now promises to achieve economies of scale previously enjoyed solely by microelectronics. By bridging the mathematical prowess of artificial neural networks to the underlying physics of optoelectronic devices, neuromorphic photonics could breach new domains of information processing demanding significant complexity, low cost, and unmatched speed. In this article, we review the progress in neuromorphic photonics, focusing on photonic integrated devices. The challenges and design rules for optoelectronic instantiation of artificial neurons are presented. The proposed photonic architecture revolves around the processing network node composed of two parts: a nonlinear element and a network interface. We then survey excitable lasers in the recent literature as candidates for the nonlinear node and microring-resonator weight banks as the network interface. Finally, we compare metrics between neuromorphic electronics and neuromorphic photonics and discuss potential applications.

  11. Progress report, 1982

    International Nuclear Information System (INIS)

    1982-01-01

    The report describes a number of areas of research at the TRIUMPH facility. Substantial progress has been made in the experiment to measure charge symmetry breaking in the n-p system. The investigations on polarized nucleon radiative capture on light nuclei have been ongoing with results of the excitation function for p + d→γ + 3 He reaction being published. Studies of the n + p→d + γ reactions are continuing. Results have been obtained in the determination of structure in the three nucleon system by studying the reaction anti d + p using tensor polarized deuterons. The Wolfenstein R-parameter in proton - 4 He elastic scattering has been measured at 500 MeV from 15 to 50 degrees (lab.) using the focal plane polarimeter on the MRS. Other experiments involving quasi-elastic scattering of polarized protons at 300 MeV, fission evaporation competition in heavy nuclei and proton-proton bremsstrahlung have been carried out. The status of the Bevelac heavy ion collaboration and the MWPC facility is also included

  12. Progressive myoclonic epilepsies

    Science.gov (United States)

    Michelucci, Roberto; Canafoglia, Laura; Striano, Pasquale; Gambardella, Antonio; Magaudda, Adriana; Tinuper, Paolo; La Neve, Angela; Ferlazzo, Edoardo; Gobbi, Giuseppe; Giallonardo, Anna Teresa; Capovilla, Giuseppe; Visani, Elisa; Panzica, Ferruccio; Avanzini, Giuliano; Tassinari, Carlo Alberto; Bianchi, Amedeo; Zara, Federico

    2014-01-01

    Objective: To define the clinical spectrum and etiology of progressive myoclonic epilepsies (PMEs) in Italy using a database developed by the Genetics Commission of the Italian League against Epilepsy. Methods: We collected clinical and laboratory data from patients referred to 25 Italian epilepsy centers regardless of whether a positive causative factor was identified. PMEs of undetermined origins were grouped using 2-step cluster analysis. Results: We collected clinical data from 204 patients, including 77 with a diagnosis of Unverricht-Lundborg disease and 37 with a diagnosis of Lafora body disease; 31 patients had PMEs due to rarer genetic causes, mainly neuronal ceroid lipofuscinoses. Two more patients had celiac disease. Despite extensive investigation, we found no definitive etiology for 57 patients. Cluster analysis indicated that these patients could be grouped into 2 clusters defined by age at disease onset, age at myoclonus onset, previous psychomotor delay, seizure characteristics, photosensitivity, associated signs other than those included in the cardinal definition of PME, and pathologic MRI findings. Conclusions: Information concerning the distribution of different genetic causes of PMEs may provide a framework for an updated diagnostic workup. Phenotypes of the patients with PME of undetermined cause varied widely. The presence of separate clusters suggests that novel forms of PME are yet to be clinically and genetically characterized. PMID:24384641

  13. Technical progress report

    International Nuclear Information System (INIS)

    1996-01-01

    This report summarizes experimental and theoretical work in basic nuclear physics carried out between October 1, 1995, the closing of our last Progress Report, and September 30, 1996 at the Nuclear Physics Laboratory of the University of Colorado, Boulder, under contracts DE-FG03-93ER-40774 and DE-FG03-95ER-40913 with the United States Department of Energy. The experimental contract supports broadly-based experimental research in intermediate energy nuclear physics. This report includes results from studies of Elementary Systems involving the study of the structure of the nucleon via polarized high-energy positron scattering (the HERMES experiment) and lower energy pion scattering from both polarized and unpolarized nucleon targets. Results from pion- and kaon-induced reactions in a variety of nuclear systems are reported under the section heading Meson Reactions; the impact of these and other results on understanding the nucleus is presented in the Nuclear Structure section. In addition, new results from scattering of high-energy electrons (from CEBAF/TJNAF) and pions (from KEK) from a broad range of nuclei are reported in the section on Incoherent Reactions. Finally, the development and performance of detectors produced by the laboratory are described in the section titled Instrumentation

  14. Resistance to technological progress

    International Nuclear Information System (INIS)

    Isensee, J.

    1983-01-01

    This article deals with the tolerance test the constitutional system (Basic Law) of the Federal Republic of Germany is currently put to as a consequence of the resistance to the power structure of this country, which is expressed in the name of protection and defense for the environment and world peace. This biopacifistic resistance movment, the author says, has nothing to do with the legal right to resist, as laid down in art. 20 (4) of the Basic Law. According to the author, this attitude is an offspring of fear of the hazards of technological progress, primarily of nuclear hazards. Practical resistance, the author states, is preceded by theoretical resistance in speech: De-legitimation of the democratic legality, of the parliamentary functions, of the supreme power of the government, and denial of the citizens duty of obedience. The author raises the question as to whether this attitude of disobedience on ecological grounds marks the onset of a fourth stage of development of the modern state, after we have passed through stages characterised by fear of civil war, of tyranny, and of social privation and suffering. There are no new ideas brought forward by the ecologically minded movement, the author says, for re-shaping our institutions or constitutional system. (HP) [de

  15. Dictyostelium Chemotaxis studied with fluorescence fluctuation spectroscopy

    NARCIS (Netherlands)

    Ruchira, A.

    2005-01-01

    The movement of cells in the direction of a chemical gradient, also known as chemotaxis, is a vital biological process. During chemotaxis, minute extracellular signals are translated into complex cellular responses such as change in morphology and motility. To understand the chemotaxis mechanism at

  16. Progress in fusion

    International Nuclear Information System (INIS)

    1959-01-01

    thermonuclear research, the work was being conducted on more or less similar lines, the basic problems encountered were the same and the results obtained were strikingly similar. Commenting on this fact, Professor Edward Teller of the United States said: 'it is remarkable how closely parallel the developments are. This is of course due to the fact that we all live in the same world and all obey the same laws of nature'. And this underlined, more than ever before, the need for a wide exchange of knowledge and experience so that duplication of effort could be avoided and progress made quicker by a pooling of information on the latest experimental results and theoretical deductions. A major concrete step in this direction has been taken by the Scientific Advisory Committee of the International Atomic Energy Agency, which recommended that the Agency should serve as the world focal point for the exchange of information on progress in thermonuclear research and plasma physics. Among the Committee's specific recommendations was that the Agency should start a scientific journal devoted exclusively to this subject. The proposed journal is expected to make its first appearance next year. It will contain, among other things, original papers on theoretical and applied research as well as on related engineering developments. Also the need arises for a permanent forum need will be met in large measure by IAEA's programme of work in this field

  17. The Thermochronologist's Progress

    Science.gov (United States)

    Zeitler, P. K.

    2011-12-01

    We owe our current understanding of thermochronology less to a series of revolutionary insights than to a somewhat uneven intellectual pilgrimage that over fifty years has progressed in fits and starts. Though hampered at times by overenthusiasm, oversimplification, and misunderstandings, on balance the field advanced thanks to a blend of curiosity-driven research, tool-building motivated by new ideas about Earth science, and improvements in technology. But now that we've exploited most radiogenic systems and the major minerals that host them, and now that our models can devour CPU time along with the best of them, are we done? Have we reached peak thermochron? The answer of course is no, and papers in this session will demonstrate what new technologies and techniques might have to offer in the coming years. However, I will argue that the discipline as a whole has matured to a point where if thermochronology is to remain a mainstream tool as opposed to a weekend sport, we need to get serious about several challenges. The most fundamental challenge is that current geodynamic models (and even more complex models we can envision coding) have outpaced our meagre stockpile of kinetic calibrations, our understanding of detailed isotope systematics, and our ability to generate data with sufficient throughput. These issues will not be addressed adequately through the business-as-usual approach that brought us to our current knowledge, and some community effort will probably be needed to coordinate the hard work that will be required. But any serious attempt to answer important questions with accurate thermal histories that have low and well-defined uncertainties will require that we actually know the kinetics for the specific samples we are analyzing, that we fully understand scatter in the data, that we work with the large sample numbers that are required for some problems like landscape evolution, and that inversion tools fully explore the important aspects of both the

  18. Medulloblastoma: progress over time

    International Nuclear Information System (INIS)

    Smee, Robert I.; Williams, Janet R.; De-loyde, Katie J.; Meagher, Nicola S.; Cohn, Richard

    2012-01-01

    Medulloblastoma is the most common central nervous system tumour in children aged 0–4 years, with 75% of cases occurring in patients <16 years, and rare in adults. The intent of this audit is to review a single centre's experience and to compare outcomes with other centres' outcomes. This Ethics approved retrospective audit evaluates the paediatric population aged <16 years who received radiotherapy as their initial or salvage treatment at the Prince of Wales Hospital Cancer Centre between 1972 and 2007. The primary and secondary end-points were progression-free survival (PFS) and cancer-specific survival (CSS), with comparisons made between patients treated before and after 1990, and the impact of high- and low-risk disease. There were 80 eligible patients, 78 who had radiotherapy at initial presentation, and 2 at the time of recurrence. Median age was 6.5 years, 52 were boys and 28 were girls. Seventy-eight patients had a surgical procedure and ultimately received craniospinal radiotherapy. Of these 78 patients, 32 (40%) had a macroscopically complete resection. The 5-year PFS was 69.7%. The 5-year PFS for patients treated pre and post 1990 was 66.1% and 71.8%, respectively. The 5-year CSS for high- and low-risk patients was 61.1% and 78.4%, respectively. Ultimately, 33% of patients were dead due to disease. This audit demonstrates those children referred to this facility for treatment have comparable survival to that of other major centres.

  19. 2004 Progress Report

    International Nuclear Information System (INIS)

    Batistoni, Paola; De Marco, Francesco; Pieroni, Leonardo

    2005-01-01

    Fusion research is undertaken all over the world with the objective of realising an environmentally responsible source of energy with essentially unlimited and widely distributed fuel reserves. The results of the worldwide efforts made in recent years are now embodied in ITER, the International Thermonuclear Experimental Reactor, designed to produce at least 500 MW of fusion power with a power gain of ten. ITER will test for the first time the interaction of fusion plasma physics with power station technology. In this international framework, during 2004 Fusion Technical and Scientific Unit of ENEA obtained important results in several keys areas. At the Frascati Tokamak Upgrade the lower hybrid microwave system was fully exploited to study the generation and control of the plasma current, and the electron cyclotron heating system reached full power (1.5 MW). With the simultaneous injection of the two waves, good energy confinement regimes with internal transport barriers were obtained at the highest plasma densities ever achieved. Advanced scenario regimes were also addressed in the activities of ENEA at JET. The engineering design of the IGNITOR machine was finalised, and significant progress was made in understanding the plasma physics regimes. Among the technology activities, the qualification of the deposition process of a copper liner on carbon fibre composite (CFC) hollow tiles may be mentioned as the most important achievement. This innovative pre brazed casting process is a competitive candidate for the fabrication of the CFCbased ITER divertor components. ENEA participated in the European activity for the definition and production on an industrial scale of an advanced Nb3Sn strand for the ITER superconducting central solenoid and toroidal field coils. Contributions were also made to the design of the final conductor layout and the characterisation tests. Inertial fusion studies continued along the previous lines, namely, the study of the implosion

  20. 1997 Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Cecchini, M.; Crescentini, L.; Ghezzi, L. [ENEA, Centro Ricerche Frascati, Rome (Italy). Nuclear fusion division

    1997-12-31

    1997 was another year of intense activity for the ENEA Nuclear Fusion Division in the evolving scenario of fusion research. With respect to the International Thermonuclear Experimental Reactor (ITER), a major review process has started, originate by the wide perception that the difficult financial situation affecting some of the parties would make it very difficult, practically impossible, to secure funding for the project as it stands. To scale down the size and cost of the machine by reducing the technical objectives, while keeping to the programmatic goal of constructing a demonstration reactor (DEMO) as the following step, appears achievable. Progress in physics was substantial during 1997. Analysis of the huge existing database, complemented by the latest results, had led to a better, more accurate scaling for the confinement time on which to base extrapolation to ITER. Studies of the very promising advanced regimes have been pursued on many tokamaks. The Frascati Tokamak Upgrade (FTU) is well placed in this respect since it is equipped with the right tools, lower hybrid and electron cyclotron radiofrequency heating and current drive systems, to explore the new promised land of low transport from the plasma core. The main highlights of FTU operation in 1997 were related to providing information relevant to these future developments. Transient production of low transport regimes with electron temperatures of 8-9 keV at the plasma center was obtained by taking advantage of the plasma skin effect and precise electron cyclotron power deposition. High-efficiency current drive at high density using lower hybrid waves was demonstrated. High-confinement pellet-enhanced modes of operation and good ion Bernstein wave coupling through the waveguide-type coupler were also achieved. Concerning the IGNITOR experiment, funds were made available only for continuation of the engineering design activities, and nothing has been released so far for manufacturing the additional

  1. 2004 Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Batistoni, Paola; De Marco, Francesco; Pieroni, Leonardo [ed.

    2005-07-01

    Fusion research is undertaken all over the world with the objective of realising an environmentally responsible source of energy with essentially unlimited and widely distributed fuel reserves. The results of the worldwide efforts made in recent years are now embodied in ITER, the International Thermonuclear Experimental Reactor, designed to produce at least 500 MW of fusion power with a power gain of ten. ITER will test for the first time the interaction of fusion plasma physics with power station technology. In this international framework, during 2004 Fusion Technical and Scientific Unit of ENEA obtained important results in several keys areas. At the Frascati Tokamak Upgrade the lower hybrid microwave system was fully exploited to study the generation and control of the plasma current, and the electron cyclotron heating system reached full power (1.5 MW). With the simultaneous injection of the two waves, good energy confinement regimes with internal transport barriers were obtained at the highest plasma densities ever achieved. Advanced scenario regimes were also addressed in the activities of ENEA at JET. The engineering design of the IGNITOR machine was finalised, and significant progress was made in understanding the plasma physics regimes. Among the technology activities, the qualification of the deposition process of a copper liner on carbon fibre composite (CFC) hollow tiles may be mentioned as the most important achievement. This innovative pre brazed casting process is a competitive candidate for the fabrication of the CFCbased ITER divertor components. ENEA participated in the European activity for the definition and production on an industrial scale of an advanced Nb3Sn strand for the ITER superconducting central solenoid and toroidal field coils. Contributions were also made to the design of the final conductor layout and the characterisation tests. Inertial fusion studies continued along the previous lines, namely, the study of the implosion

  2. 1997 Progress report

    International Nuclear Information System (INIS)

    Cecchini, M.; Crescentini, L.; Ghezzi, L.

    1997-01-01

    1997 was another year of intense activity for the ENEA Nuclear Fusion Division in the evolving scenario of fusion research. With respect to the International Thermonuclear Experimental Reactor (ITER), a major review process has started, originate by the wide perception that the difficult financial situation affecting some of the parties would make it very difficult, practically impossible, to secure funding for the project as it stands. To scale down the size and cost of the machine by reducing the technical objectives, while keeping to the programmatic goal of constructing a demonstration reactor (DEMO) as the following step, appears achievable. Progress in physics was substantial during 1997. Analysis of the huge existing database, complemented by the latest results, had led to a better, more accurate scaling for the confinement time on which to base extrapolation to ITER. Studies of the very promising advanced regimes have been pursued on many tokamaks. The Frascati Tokamak Upgrade (FTU) is well placed in this respect since it is equipped with the right tools, lower hybrid and electron cyclotron radiofrequency heating and current drive systems, to explore the new promised land of low transport from the plasma core. The main highlights of FTU operation in 1997 were related to providing information relevant to these future developments. Transient production of low transport regimes with electron temperatures of 8-9 keV at the plasma center was obtained by taking advantage of the plasma skin effect and precise electron cyclotron power deposition. High-efficiency current drive at high density using lower hybrid waves was demonstrated. High-confinement pellet-enhanced modes of operation and good ion Bernstein wave coupling through the waveguide-type coupler were also achieved. Concerning the IGNITOR experiment, funds were made available only for continuation of the engineering design activities, and nothing has been released so far for manufacturing the additional

  3. HYLIFE-2 progress report

    International Nuclear Information System (INIS)

    Moir, R.W.; Adamson, M.G.; Bangerter, R.O.; Bieri, R.L.; Condit, R.H.; Hartman, C.W.; House, P.A.; Langdon, A.B.; Logan, B.G.; Orth, C.D.; Petzoldt, R.W.; Pitts, J.H.; Post, R.F.; Sacks, R.A.; Tobin, M.T.; Williams, W.H.; Dolan, T.J.; Longhurst, G.R.; Hoffman, M.A.; Meier, W.R.

    1991-12-01

    LIFE-II inertial confinement fusion power plant design study uses a liquid fall, in the form of jets to protect the first structural wall from neutron damage, x rays, and blast to provide a 30-y lifetime. This is a progress report of an incomplete and ongoing study. HYLIFE-I used liquid lithium. HYLIFE-11 avoids the fire hazard of lithium by using a molten salt composed of fluorine, lithium, and beryllium (Li 2 Be 4 ) called Flibe. Access for heavy-ion beams is provided. Calculations for assumed heavy-ion beam performance show a nominal gain of 70 at 5 MJ producing 350 MJ, about 5.2 times less yield than the 1.8 GJ from a driver energy of 4.5 MJ with gain of 400 for HYLIFE-I. The nominal 1 GWe of power can be maintained by increasing the repetition rate by a factor of about 5.2, from 1.5 to 8 Hz. A higher repetition rate requires faster re-establishment of the jets after a shot, which can be accomplished in part by decreasing the jet fall height and increasing the jet flow velocity. Multiple chambers may be required.In addition, although not considered for HYLIFE-I there is undoubtedly liquid splash that must be forcibly cleared because gravity is too slow, especially at high repetition rates. Splash removal can be accomplished by either pulsed or oscillating jet flows. The cost of electricity is estimated to be 0.10 $/kW· in constant 1990 dollars, about twice that of future coal and light water reactor nuclear power. The driver beam cost is about one-half the total cost

  4. Progress report 2000

    International Nuclear Information System (INIS)

    2001-01-01

    Clean Air Hamilton is the new name of the Hamilton-Wentworth Air Quality Initiative and its implementation committee, which began in 1995 as a collaborative, multi-sectoral effort to identify and examine important air quality issues and to implement strategies to reduce many of the harmful emissions that endanger human health. During the year 2000 Clean Air Hamilton focused on nine program areas. Strategies were initiated to (1) reduce single occupancy auto trips, (2) purchase low emission vehicles, (3) model transportation emissions, (4) reduce smog-causing emissions, (5) plant trees, (6) provide advice on air quality related land use and transportation issues for consideration in city-wide planning, (7) promote public awareness through social marketing, (8) study fugitive road dust, and (9) reduce transboundary air pollution. A number of indicators to measure progress in efforts to improve air quality have been developed; many of these indicators show significant improvements which, taken collectively, show a positive trend toward cleaner air. The report highlights major accomplishment of Clean Air Hamilton; reports trends in ambient air quality data; assesses human health impacts of air quality, and recommends strategies for further improvements. Among major improvements, inhalable particulate (PM10) levels have decreased by about 20 per cent since 1991; sulphur dioxide levels dropped by 40 per cent since 1989 at industrial sampling sites and 20 per cent at the downtown sampling site; the air pollution index has remained under the advisory level of 32 at all API stations in Hamilton since June 1996. Benzene levels in air decreased by over 50 per cent near the Dofasco plant compared to the five-year composite average from 1994-1998. Given these accomplishments, participants in Clean Air Hamilton believe that while there is much room for improvement, the efforts to date have been worthwhile and provide encouragement for the future. 14 figs., 4 appendices

  5. 1997 Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Cecchini, M; Crescentini, L; Ghezzi, L [ENEA, Centro Ricerche Frascati, Rome (Italy). Nuclear fusion division

    1998-12-31

    1997 was another year of intense activity for the ENEA Nuclear Fusion Division in the evolving scenario of fusion research. With respect to the International Thermonuclear Experimental Reactor (ITER), a major review process has started, originate by the wide perception that the difficult financial situation affecting some of the parties would make it very difficult, practically impossible, to secure funding for the project as it stands. To scale down the size and cost of the machine by reducing the technical objectives, while keeping to the programmatic goal of constructing a demonstration reactor (DEMO) as the following step, appears achievable. Progress in physics was substantial during 1997. Analysis of the huge existing database, complemented by the latest results, had led to a better, more accurate scaling for the confinement time on which to base extrapolation to ITER. Studies of the very promising advanced regimes have been pursued on many tokamaks. The Frascati Tokamak Upgrade (FTU) is well placed in this respect since it is equipped with the right tools, lower hybrid and electron cyclotron radiofrequency heating and current drive systems, to explore the new promised land of low transport from the plasma core. The main highlights of FTU operation in 1997 were related to providing information relevant to these future developments. Transient production of low transport regimes with electron temperatures of 8-9 keV at the plasma center was obtained by taking advantage of the plasma skin effect and precise electron cyclotron power deposition. High-efficiency current drive at high density using lower hybrid waves was demonstrated. High-confinement pellet-enhanced modes of operation and good ion Bernstein wave coupling through the waveguide-type coupler were also achieved. Concerning the IGNITOR experiment, funds were made available only for continuation of the engineering design activities, and nothing has been released so far for manufacturing the additional

  6. Scientific Progress in Strategic Management

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul

    Does the RBV represent a case of scientific progress? And has it emerged as the dominant approach to the analysis of competitive advantage for this reason? Conventional criteria for scientific progress, notably those of the growth of knowledge literature, are not particularly helpful for understa...

  7. Periodic progress report, 6 months

    DEFF Research Database (Denmark)

    Juhl, Thomas Winther; Nielsen, Jakob Skov

    This is the first progress report of the BriteEuram project named "High Power Laser Cutting for Heavy Industry" ("Powercut"). The report contains a summary of the objectives of the first period, an overview of the technical progress, a comparison between the planed and the accomplished work...

  8. Progress report. P6

    International Nuclear Information System (INIS)

    Manokhin, V.N.; Maev, S.A.

    2001-01-01

    In CJD the current work continued concerning EXFOR compilation and fulfillment of NRDC-2000 Recommendations and Actions. Much efforts were applied for restoring CJD Web page. Evaluation works were also in process. Compilation into EXFOR continues on steadily. Since March 2000 up to April 2001 four TRANS tapes containing 69 Entries were prepared and sent to other centers. 25 new EXFOR Entries were compiled. An analysis and an evaluation are made for the threshold reactions cross sections leading to production of the long-lived radioactive nuclides on the irradiation of steel by thermonuclear neutron spectrum. Fifty excitation functions were evaluated. Many of them are considerably different from available evaluations of other libraries. During two years, together with JAERI, comparative analysis was performed of (n,2n) and (n,3n) reactions for 150 fission products from available evaluated data libraries. The result of analysis will be published this year. The joint work on consistent evaluation of some (n,2n) and (n,np) excitation functions for even-even isotopes was made on the basis of empirical systematics. The work was completed on evaluation of the spectra and production cross sections of gamma-rays in inelastic interactions of 14-Mev neutrons with the number of nuclei: Li-6, Li-7, Al, Ti, Cr, Fe, Cu, Pb, Bi, U-235. CJD continues the work on evaluation of neutron data for minor actinides. This year Am-242m will be evaluated, and Np-237, Am-241, Am-243, Cm-243, Cm-244 will be tested and improved. Full file of Bi was prepared. Full files for Pb isotopes are in process of preparation. There exist a plan to analyze full files for isotopes of Cr, Fe, Ni from existing evaluated data libraries, to select more reliable cross sections, and to create improved files for these isotopes. Together with the Theoretical Department the work is in progress on the determination of uncertainties of existing evaluated data and development of covariance matrices for some important

  9. CBM progress report 2007

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, N.; Rami, F.; Roehrich, D.; Stroth, J.; Wessels, J.; Zaitsev, Yu

    2008-02-15

    This report documents the activities within the CBM project in 2007. Significant progress has been made in the optimization of the simulation software, the layout and development of detectors, the design of front-end electronics, and the concepts for data acquisition. The simulation and analysis routines have been completely integrated into the software framework (FAIRoot and CBMroot), and can be used now easily by users outside GSI. A breakthrough has been achieved in the development of fast algorithms for track and vertex reconstruction which have been improved in speed by a factor of 10{sup 5}. These fast routines permit to perform high-statistics simulations for detailed detector layout optimization. Full event reconstruction based on realistic detector properties and particle multiplicities as given by microscopic transport models are routinely used in the feasibility studies. A version of the Silicon Tracking System is now implemented in the simulation software comprising 8 detector layers based on microstrip technology only, including the readout cables, and the mechanical detector structure. The studies of open charm detection have been extended to D{sub s}{sup +} and {lambda}{sub c}, taking into account a realistic layout of the Silicon Pixel Microvertex detector. The identification of electrons has been optimized by improved ring recognition algorithms and transition radiation simulations. The Ring Imaging Cherenkov (RICH) detector has been redesigned, resulting in a reduction by a factor of two in mirror size and number of readout channels without reducing the pion rejection capability. The muon detection system has been optimized with respect to the number of detector layers. The muon simulations take into account detector inefficiencies and a segmentation of the muon chambers into pads according to a nominal occupancy of 5% for central Au+Au collisions. Studies for a dimuon trigger show promising results. Radiation dose simulations using the FLUKA

  10. CBM progress report 2007

    International Nuclear Information System (INIS)

    Herrmann, N.; Rami, F.; Roehrich, D.; Stroth, J.; Wessels, J.; Zaitsev, Yu

    2008-02-01

    This report documents the activities within the CBM project in 2007. Significant progress has been made in the optimization of the simulation software, the layout and development of detectors, the design of front-end electronics, and the concepts for data acquisition. The simulation and analysis routines have been completely integrated into the software framework (FAIRoot and CBMroot), and can be used now easily by users outside GSI. A breakthrough has been achieved in the development of fast algorithms for track and vertex reconstruction which have been improved in speed by a factor of 10 5 . These fast routines permit to perform high-statistics simulations for detailed detector layout optimization. Full event reconstruction based on realistic detector properties and particle multiplicities as given by microscopic transport models are routinely used in the feasibility studies. A version of the Silicon Tracking System is now implemented in the simulation software comprising 8 detector layers based on microstrip technology only, including the readout cables, and the mechanical detector structure. The studies of open charm detection have been extended to D s + and Λ c , taking into account a realistic layout of the Silicon Pixel Microvertex detector. The identification of electrons has been optimized by improved ring recognition algorithms and transition radiation simulations. The Ring Imaging Cherenkov (RICH) detector has been redesigned, resulting in a reduction by a factor of two in mirror size and number of readout channels without reducing the pion rejection capability. The muon detection system has been optimized with respect to the number of detector layers. The muon simulations take into account detector inefficiencies and a segmentation of the muon chambers into pads according to a nominal occupancy of 5% for central Au+Au collisions. Studies for a dimuon trigger show promising results. Radiation dose simulations using the FLUKA transport code have been

  11. Psychological functioning in primary progressive versus secondary progressive multiple sclerosis

    DEFF Research Database (Denmark)

    Vleugels, L; Pfennings, L E; Pouwer, F

    1998-01-01

    Psychological functioning in two types of multiple sclerosis (MS) patients is assessed: primary progressive (PP) and secondary progressive (SP) patients. On the basis of differences in clinical course and underlying pathology we hypothesized that primary progressive patients and secondary...... progressive patients might have different psychological functioning. Seventy patients treated in an MS centre were examined cross-sectionally. Forty had an SP course of MS and 30 a PP course. The 33 male and 37 female patients had a mean age of 48.4 years (SD 11.2) and mean age of onset of MS of 30.7 years...... (SD 11.1). Patients completed questionnaires measuring among others the following aspects of psychological functioning: depression (BDI, SCL-90), anxiety (STAI, SCL-90), agoraphobia (SCL-90), somatic complaints (SCL-90), hostility (SCL-90) and attitude towards handicap (GHAS). Patients with a PP...

  12. Federal Facility Agreement progress report

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-01

    The (SRS) Federal Facility Agreement (FFA) was made effective by the US. Environmental Protection Agency Region IV (EPA) on August 16, 1993. To meet the reporting requirements in Section XXV of the Agreement, the FFA Progress Report was developed. The FFA Progress Report is the first of a series of quarterly progress reports to be prepared by the SRS. As such this report describes the information and action taken to September 30, 1993 on the SRS units identified for investigation and remediation in the Agreement. This includes; rubble pits, runoff basins, retention basin, seepage basin, burning pits, H-Area Tank 16, and spill areas.

  13. Progressive Taxation and Tax Morale

    OpenAIRE

    Philipp Doerrenberg; Andreas Peichl

    2010-01-01

    As the link between tax compliance and tax morale is found to be robust, finding the determinants of tax morale can help to understand and fight tax evasion. In this paper we analyze the effect of progressive taxation on tax morale in a cross-country approach - which has not been investigated before. Our theoretical analysis leads to two testable predictions. First, an individual's tax morale is higher, the more progressive the tax schedule is. Second, the impact of tax progressivity on tax m...

  14. Federal Facility Agreement progress report

    International Nuclear Information System (INIS)

    1993-10-01

    The (SRS) Federal Facility Agreement (FFA) was made effective by the US. Environmental Protection Agency Region IV (EPA) on August 16, 1993. To meet the reporting requirements in Section XXV of the Agreement, the FFA Progress Report was developed. The FFA Progress Report is the first of a series of quarterly progress reports to be prepared by the SRS. As such this report describes the information and action taken to September 30, 1993 on the SRS units identified for investigation and remediation in the Agreement. This includes; rubble pits, runoff basins, retention basin, seepage basin, burning pits, H-Area Tank 16, and spill areas

  15. Early detection of emphysema progression

    DEFF Research Database (Denmark)

    Gorbunova, Vladlena; Jacobs, Sander S A M; Lo, Pechin

    2010-01-01

    Emphysema is one of the most widespread diseases in subjects with smoking history. The gold standard method for estimating the severity of emphysema is a lung function test, such as forced expiratory volume in first second (FEV1). However, several clinical studies showed that chest CT scans offer...... more sensitive estimates of emphysema progression. The standard CT densitometric score of emphysema is the relative area of voxels below a threshold (RA). The RA score is a global measurement and reflects the overall emphysema progression. In this work, we propose a framework for estimation of local...... emphysema progression from longitudinal chest CT scans. First, images are registered to a common system of coordinates and then local image dissimilarities are computed in corresponding anatomical locations. Finally, the obtained dissimilarity representation is converted into a single emphysema progression...

  16. Zolpidem in Progressive Supranuclear Palsy

    Directory of Open Access Journals (Sweden)

    Sandip K. Dash

    2013-01-01

    Full Text Available Progressive supranuclear palsy (PSP is a progressive neurodegenerative disorder, characterized by motor symptoms, postural instability, personality changes, and cognitive impairment. There is no effective treatment for this disorder. Reduced neurotransmission of GABA in the striatum and globus pallidus may contribute to the symptoms of motor and cognitive symptoms seen in PSP. Zolpidem is a GABA agonist of the benzodiazepine subreceptor BZ1. Here a nondiabetic, normotensive case of PSP is (Progressive Supranuclear Palsy described, which showed improvement in swallowing, speech, and gaze paresis after zolpidem therapy and possible mechanism of actions are discussed. However, more trials are needed with large number of patients to confirm the effectiveness of zolpidem in progressive supranuclear palsy.

  17. Progresses in proton radioactivity studies

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, L. S., E-mail: flidia@ist.utl.pt [Center of Physics and Engineering of Advanced Materials, CeFEMA and Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, P1049-001 Lisbon (Portugal); Maglione, E. [Dipartimento di Fisica e Astronomia “G. Galilei”, Via Marzolo 8, I-35131 Padova, Italy and Istituto Nazionale di Fisica Nucleare, Padova (Italy)

    2016-07-07

    In the present talk, we will discuss recent progresses in the theoretical study of proton radioactivity and their impact on the present understanding of nuclear structure at the extremes of proton stability.

  18. Nitrate | Cancer Trends Progress Report

    Science.gov (United States)

    The Cancer Trends Progress Report, first issued in 2001, summarizes our nation's advances against cancer in relation to Healthy People targets set forth by the Department of Health and Human Services.

  19. Sunburn | Cancer Trends Progress Report

    Science.gov (United States)

    The Cancer Trends Progress Report, first issued in 2001, summarizes our nation's advances against cancer in relation to Healthy People targets set forth by the Department of Health and Human Services.

  20. Preventing Breast Cancer: Making Progress

    Science.gov (United States)

    ... Navigation Bar Home Current Issue Past Issues Preventing Breast Cancer: Making Progress Past Issues / Fall 2006 Table of ... 000 women will have been diagnosed with invasive breast cancer, and nearly 41,000 women will die from ...

  1. Defining active progressive multiple sclerosis

    DEFF Research Database (Denmark)

    Sellebjerg, Finn; Börnsen, Lars; Ammitzbøll, Cecilie

    2017-01-01

    BACKGROUND: It is unknown whether disease activity according to consensus criteria (magnetic resonance imaging activity or clinical relapses) associate with cerebrospinal fluid (CSF) changes in progressive multiple sclerosis (MS). OBJECTIVE: To compare CSF biomarkers in active and inactive...

  2. Annual Progress report - General Task

    International Nuclear Information System (INIS)

    Wesnousky, S.G.

    1993-01-01

    This report provides a summary of progress for the project open-quotes Evaluation of the Geologic Relations and Seismotectonic Stability of the Yucca Mountain Area, Nevada Nuclear Waste Site Investigation (NNWSI).close quotes A similar report was previously provided for the period of 1 October 1991 to 30 September 1992. The report initially covers the activities of the General Task and is followed by sections that describe the progress of the other ongoing tasks

  3. Progressive technologies in furniture design

    OpenAIRE

    Šebková, Martina

    2014-01-01

    Šebková, M. Progressive technologies in furniture design. Diploma thesis, Brno, Mendel University in Brno, 2014 Diploma thesis 'Progressive technologies in furniture design' is focused on the use of modern technologies in furniture production. The theoretical part explains the basic terms, technology and material options. It focuses mainly on the production of 3D printed furniture and possibilities of virtual testing, measurements, scanning and rapid prototyping. Practical part of diploma the...

  4. Targeting ECM Disrupts Cancer Progression

    DEFF Research Database (Denmark)

    Venning, Freja A; Wullkopf, Lena; Erler, Janine T

    2015-01-01

    , the extracellular matrix (ECM). Many ECM proteins are significantly deregulated during the progression of cancer, causing both biochemical and biomechanical changes that together promote the metastatic cascade. In this review, the influence of several ECM proteins on these multiple steps of cancer spread...... is summarized. In addition, we highlight the promising (pre-)clinical data showing benefits of targeting these ECM macromolecules to prevent cancer progression....

  5. Scientific progress as increasing verisimilitude.

    Science.gov (United States)

    Niiniluoto, Ilkka

    2014-06-01

    According to the foundationalist picture, shared by many rationalists and positivist empiricists, science makes cognitive progress by accumulating justified truths. Fallibilists, who point out that complete certainty cannot be achieved in empirical science, can still argue that even successions of false theories may progress toward the truth. This proposal was supported by Karl Popper with his notion of truthlikeness or verisimilitude. Popper's own technical definition failed, but the idea that scientific progress means increasing truthlikeness can be expressed by defining degrees of truthlikeness in terms of similarities between states of affairs. This paper defends the verisimilitude approach against Alexander Bird who argues that the "semantic" definition (in terms of truth or truthlikeness alone) is not sufficient to define progress, but the "epistemic" definition referring to justification and knowledge is more adequate. Here Bird ignores the crucial distinction between real progress and estimated progress, explicated by the difference between absolute (and usually unknown) degrees of truthlikeness and their evidence-relative expected values. Further, it is argued that Bird's idea of returning to the cumulative model of growth requires an implausible trick of transforming past false theories into true ones.

  6. Progression of chronic renal failure.

    Science.gov (United States)

    Hakim, R M; Lazarus, J M

    1989-11-01

    Rates of progression of renal failure were calculated for a group of 277 patients who had five or more clinic visits. The goals of therapy in the absence of ongoing immunological processes were control of blood pressure to diastolic pressures less than 85 mm Hg and serum phosphate less than 1.60 mmol/L (5 mg/dL). The mean rate of progression expressed as the slope of the reciprocal creatinine versus time was -0.0054 +/- 0.0009 dL/mg/mo (mean +/- SEM), and the median was -0.00315 dL/mg/mo. Approximately 25% of these patients had rates of progression less than -0.001 dL/mg/mo. The rate of progression was inversely correlated with the creatinine concentration at entry (P less than 0.004) and with the frequency of clinic visits (P less than 0.01). The "renal survival" time from a creatinine of 880 mumol/L (10 mg/dL) to dialysis was 10.0 +/- 1.2 months (mean +/- SEM). These data provide rates of progression for a group of patients without specific dietary intervention but with vigorous control of blood pressure and phosphorus.

  7. Tracking Clean Energy Progress 2013

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-06-01

    Tracking Clean Energy Progress 2013 (TCEP 2013) examines progress in the development and deployment of key clean energy technologies. Each technology and sector is tracked against interim 2020 targets in the IEA Energy Technology Perspectives 2012 2°C scenario, which lays out pathways to a sustainable energy system in 2050. Stark message emerge: progress has not been fast enough; large market failures are preventing clean energy solutions from being taken up; considerable energy efficiency remains untapped; policies need to better address the energy system as a whole; and energy-related research, development and demonstration need to accelerate. Alongside these grim conclusions there is positive news. In 2012, hybrid-electric vehicle sales passed the 1 million mark. Solar photovoltaic systems were being installed at a record pace. The costs of most clean energy technologies fell more rapidly than anticipated.

  8. Building a progressive vertical integration

    International Nuclear Information System (INIS)

    Charette, D.

    2008-01-01

    AAER Inc. is a Quebec-based company that manufactures turbines using proven European designs. This presentation discussed the company's business model. The company places an emphasis on identifying strategic and key components currently available for its turbines. Market analyses are performed in order to determine ideal suppliers and define business strategies and needs. The company invests in long-term relationships with its suppliers. Business partners for AAER are of a similar size and have a mutual understanding and respect for the company's business practices. Long-term agreements with suppliers are signed in order to ensure reliability and control over costs. Progressive vertical integration has been achieved by progressively manufacturing key components and integrating a North American supply chain. The company's secure supply chain and progressive vertical integration has significantly reduced financial costs and provided better quality control. It was concluded that vertical integration has also allowed AAER to provide better customer service and reduce transportation costs. tabs., figs

  9. Rapidly Progressive Quadriplegia and Encephalopathy.

    Science.gov (United States)

    Wynn, DonRaphael; McCorquodale, Donald; Peters, Angela; Juster-Switlyk, Kelsey; Smith, Gordon; Ansari, Safdar

    2016-11-01

    A woman aged 77 years was transferred to our neurocritical care unit for evaluation and treatment of rapidly progressive motor weakness and encephalopathy. Examination revealed an ability to follow simple commands only and abnormal movements, including myoclonus, tongue and orofacial dyskinesias, and opsoclonus. Imaging study findings were initially unremarkable, but when repeated, they demonstrated enhancement of the cauda equina nerve roots, trigeminal nerve, and pachymeninges. Cerebrospinal fluid examination revealed mildly elevated white blood cell count and protein levels. Serial electrodiagnostic testing demonstrated a rapidly progressive diffuse sensory motor axonopathy, and electroencephalogram findings progressed from generalized slowing to bilateral periodic lateralized epileptiform discharges. Critical details of her recent history prompted a diagnostic biopsy. Over time, the patient became completely unresponsive with no further abnormal movements and ultimately died. The differential diagnosis, pathological findings, and diagnosis are discussed with a brief review of a well-known yet rare diagnosis.

  10. World progress toward fusion energy

    International Nuclear Information System (INIS)

    Davies, N.A.

    1989-01-01

    The author discusses international progress in fusion research during the last three years. Much of the technical progress has been achieved through international collaboration in magnetic fusion research. This progress has stimulated political interest in a multinational effort, aimed at designing and possibly constructing the world's first experimental fusion reactor. This interest was reflected in recent summit-level discussions involving President Mitterand, General Secretary Gorbachev, and President Reagan. Most recently, the European Community (EC), Japan, the United States, and the U.S.S.R. have decided to begin serious preparation for taking the next step toward practical fusion energy. These parties have agreed to begin the design and supporting R and D for an International Thermonuclear Experimental Reactor (ITER) under the auspices of the International Atomic Energy Agency (IAEA). The initiation of this international program to prepare for a fusion test reactor is discussed

  11. Biogas Opportunities Roadmap Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2015-12-01

    In support of the Obama Administration's Climate Action Plan, the U.S. Department of Energy, the U.S. Environmental Protection Agency, and U.S. Department of Agriculture jointly released the Biogas Opportunities Roadmap Progress Report, updating the federal government's progress to reduce methane emissions through biogas systems since the Biogas Opportunities Roadmap was completed by the three agencies in July 2014. The report highlights actions taken, outlines challenges and opportunities, and identifies next steps to the growth of a robust biogas industry.

  12. Communication of nuclear data progress

    International Nuclear Information System (INIS)

    2001-01-01

    This is the 26th issue of Communication of Nuclear Data Progress (CNDP), in which the progress and achievements in nuclear data field from the last year up to now in China are carried. It includes the measurements of 71 Ga, 94 Zn, 191 Ir, 174 Hf(n, γ) and 114 Cd(n, 2n) cross sections, fission product yields of n + 235,238 U, DPA cross section calculated with UNF code, fission barrier parameter evaluation of some nuclides, production and transmission of covariance in the evaluation processing of fission yield data and transition analysis of Ne-like Ge XXIII

  13. Progressive macular hypomelanosis: an overview

    NARCIS (Netherlands)

    Relyveld, Germaine N.; Menke, Henk E.; Westerhof, Wiete

    2007-01-01

    Progressive macular hypomelanosis (PMH) is a common skin disorder that is often misdiagnosed. Various authors have written about similar skin disorders, referring to them by different names, but we believe that all these similar disorders are part of the same entity.PMH is characterized by

  14. Progress Report 1985-1986

    International Nuclear Information System (INIS)

    1987-01-01

    The research directions in the Physics Institute of Universidade Federal do Rio Grande do Sul are presented. The progress reports cavied out in the follow areas are presented: perturbed angular correlation; Moessbauer spectroscopy; ion implantation; magnetism and electronic transport; microelectronics; condensed matter theory; quantum field theory; plasma physics; nuclear physics; astronomy and astrophysics; and instrumentation. (M.C.K.) [pt

  15. Technological Progress, Exit and Trade

    DEFF Research Database (Denmark)

    Schröder, Philipp; Sørensen, Allan

    productivity exporters are more likely to continue to export, and market exit is typically preceded by periods of contracting market shares. We show that the simple inclusion of exogenous economy wide technological progress into the standard Melitz (2003) model generates a tractable dynamic framework...

  16. Progress in color night vision

    NARCIS (Netherlands)

    Toet, A.; Hogervorst, M.A.

    2012-01-01

    We present an overview of our recent progress and the current state-of-the-art techniques of color image fusion for night vision applications. Inspired by previously developed color opponent fusing schemes, we initially developed a simple pixel-based false color-mapping scheme that yielded fused

  17. Recent progress in sodium technology

    Energy Technology Data Exchange (ETDEWEB)

    Hallett, W. J.

    1963-10-15

    Progress over the past year in U. S. laboratories studying some of the materials and engineering problems that must be resolved in bringing the technology of sodium to an economically and technically attractive point is reviewed. The status of sodium cooled power reactors in the U. S. is described. (P.C.H.)

  18. Progress report 1971/72

    International Nuclear Information System (INIS)

    1972-01-01

    The progress report comprises reports from interdisciplinary task groups on radiation protection, isotope application and radiation measurement technique, microscopy, linear accelerators, process computers, biophysics and nuclear physics. The last task group reports on work with the electron linear accelerator, nuclear spectroscopy, neutron physics, work with polarized particles, and experiments with the GSI heavy ion accelerator. (orig./AK) [de

  19. Popular support for progressive taxation

    OpenAIRE

    Marhuenda Hurtado, Francisco; Ortuño Ortín, Ignacio Isidro

    1995-01-01

    The popular support obtained by two parties who propose two qualitatively different tax schernes is analyzed. We show that if the median voter is below the mean, then any progressive proposal always wins over a regressive one, provided it leaves the poorest agent at least as well off as the latter does.

  20. Progress at the Shanghai EBIT

    International Nuclear Information System (INIS)

    He Mianhong; Liu Yong; Yang Yang; Wu Shimin; Chen Weidong; Hu Wei; Guo, Panlin; Lu Di; Fu Yunqing; Huang Min; Zhang Xuemei; Hutton, Roger; Liljeby, Leif; Zou Yaming

    2007-01-01

    In this report, a brief description of the progress of the Shanghai EBIT project is presented. This is followed by short discussions on the X ray spectra at several electron beam energies and the ion densities in the EBIT at a specific running condition

  1. Progress in semiconductor drift detectors

    International Nuclear Information System (INIS)

    Rehak, P.; Walton, J.; Gatti, E.

    1985-01-01

    Progress in testing semiconductor drift detectors is reported. Generally better position and energy resolutions were obtained than resolutions published previously. The improvement is mostly due to new electronics better matched to different detectors. It is shown that semiconductor drift detectors are becoming versatile and reliable detectors for position and energy measurements

  2. Annual progress report FY 1977

    International Nuclear Information System (INIS)

    Hansen, K.F.; Henry, A.F.

    1977-07-01

    Progress is summarized in a project directed toward development of numerical methods suitable for the computer solution of problems in reactor dynamics and safety. Specific areas of research include methods of integration of the time-dependent diffusion equations by finite difference and finite element methods; representation of reactor properties by various homogenization procedures; application of synthesis methods; and development of response matrix techniques

  3. Minority Student Progress Report, 1991.

    Science.gov (United States)

    Diaz, Porfirio R.; Luan, Jing

    This report offers a consolidated systemwide analysis of key issues and recommendations for improvement of minority recruitment and retention at Arizona State Universities and an evaluation of progress toward achieving Arizona Board of Regents (ABOR) approved recruitment and graduation goals. A description of ABOR system goals notes three goals:…

  4. Nuclear Physics Division progress report

    International Nuclear Information System (INIS)

    West, D.; Cookson, J.A.; Findlay, D.J.S.

    1984-06-01

    The 1983 progress report of the Nuclear Physics Division, UKAEA Harwell, is divided into four main topics. These are a) nuclear data and technology for nuclear power; b) nuclear studies; c) applications of nuclear and associated techniques, including ion beam techniques and moessbauer spectroscopy; and d) accelerator operation, maintenance and development. (U.K.)

  5. Progress in pulsed power fusion

    Energy Technology Data Exchange (ETDEWEB)

    Quintenz, J P; Adams, R G; Bailey, J E [Sandia Labs., Albuquerque, NM (United States); and others

    1997-12-31

    Pulsed power offers an efficient, high energy, economical source of x-rays for inertial confinement fusion (ICF) research. Two main approaches to ICF driven with pulsed power accelerators are pursued: intense light ion beams and z-pinches. Recent progress in each approach and plans for future development is described. (author). 2 figs., 10 refs.

  6. Ultrasonic flowmeters. Progress report II

    International Nuclear Information System (INIS)

    Wittekind, W.D.

    1980-01-01

    This progress report presents results of in-plant testing of the prototype ultrasonic flowmeter and describes modifications to the prototype as a result of these tests. The modified prototype, designated MOD-I, is described in detail including the principle of operation, equipment used and the results of both laboratory and in-plant demonstrations

  7. Progress: Its Glories and Pitfalls.

    Science.gov (United States)

    Callahan, Daniel

    2018-03-01

    Steven Pinker, a cognitive psychologist and linguist at Harvard and a savant of big ideas, is one of the latest to take on the idea of progress. He does it under the aegis of "enlightenment," which comes down to a kind of holy trinity of reason, science, and humanism. His new book, Enlightenment Now: The Case for Reason, Science, Humanism, and Progress, is ambitious and cantankerous and heady with hope. On the whole, Pinker makes a good case for the benefits of progress, but with an overdose of feel-good prose. His greatest failure comes in exaggerating the threats to science and in avoiding some problems altogether. He ignores its complexity, its shadows, its creation of new problems raised by its solutions to old ones. Pinker has a particular animus against bioethics, and he misses what has been, I would argue, at the heart of bioethics from its beginning fifty or so years ago. Bioethics was prompted by a new class of medical dilemmas that require a difficult balancing of harms and benefits. Most of them are still with us, and most of them are the result of the progress of postwar medical research and fast-changing clinical practices. © 2018 The Hastings Center.

  8. Progress in pulsed power fusion

    International Nuclear Information System (INIS)

    Quintenz, J.P.; Adams, R.G.; Bailey, J.E.

    1996-01-01

    Pulsed power offers an efficient, high energy, economical source of x-rays for inertial confinement fusion (ICF) research. Two main approaches to ICF driven with pulsed power accelerators are pursued: intense light ion beams and z-pinches. Recent progress in each approach and plans for future development is described. (author). 2 figs., 10 refs

  9. FMIT Test assemblies. Progress report

    International Nuclear Information System (INIS)

    Nygren, R.E.; Opperman, E.K.

    1978-08-01

    This progress report is a reference document for a number of inter-related tasks supporting the Fusion Materials Irradiation Test (FMIT) Facility being developed by the Hanford Engineering Development Laboratory. The report describes the basic configuration of test assemblies and supporting rationale based on the neutron flux distribution. Perturbed and unperturbed flux profiles are discussed as well as heating rates and cooling requirements

  10. Monitoring Students' Academic & Disciplinary Progression.

    Science.gov (United States)

    McDonald, Fred; Kellogg, Larry J.

    This document outlines the objectives and procedures of a program at a New Mexico school district whose purpose is to enable school personnel to systematically monitor students' academic and disciplinary progression. The objectives of the program are to diagnose academic or disciplinary problems and prescribe remedies, to establish an oncampus…

  11. Geothermal Progress Monitor report No. 5. Progress report, June 1981

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    Updated information is presented on activities and progress in the areas of electric power plants, direct heat applications, deep well drilling, leasing of federal lands, legislative and regulatory actions, research and development, and others. Special attention is given in this report to 1980 highlights, particularly in the areas of electric and direct heat uses, drilling, and the Federal lands leasing program. This report also includes a summary of the DOE FY 1982 geothermal budget request to Congress.

  12. The Efficient Side of Progressive Income Taxation

    OpenAIRE

    Corneo, Giacomo

    2000-01-01

    This paper examines the allocative implications of progressive income taxation when individuals care about their relative income. It shows that tax progressivity might improve efficiency, and the more so in egalitarian economies. Introducing a progressive income tax can yield a Pareto improvement if pre-tax income is evenly distributed. Implementing undistorted choices of working hours requires a progressive tax schedule, and the optimal degree of progressivity decreases with pre-tax income i...

  13. Progress of MICE RFCC Module

    Energy Technology Data Exchange (ETDEWEB)

    Li, D.; Bowring, D.; DeMello, A.; Gourlay, S.; Green, M.; Li, N.; Niinikoski, T.; Pan, H.; Prestemon, S.; Virostek, S.; Zisman, M.; Bross, A.; Carcagno, R.; Kashikhin, V.; Sylvester, C.; Chen, A. B.; Guo, Bin; Li, Liyi; Xu, Fengyu; Cao, Y.; Sun, S.; Wang, Li; Yin, Lixin; Luo, Tianhuan; Summers, Don; Smith, B.; Radovinsky, A.; Zhukovsky, A.; Kaplan, D.

    2012-05-20

    Recent progress on the design and fabrication of the RFCC (RF and superconducting Coupling Coil) module for the international MICE (Muon Ionization Cooling Experiment) are reported. The MICE ionization cooling channel has two RFCC modules, each having four 201- MHz normal conducting RF cavities surrounded by one superconducting coupling coil (solenoid) magnet. The magnet is designed to be cooled by three cryocoolers. Fabrication of the RF cavities is complete; preparation for the cavity electro-polishing, low power RF measurements, and tuning are in progress at Lawrence Berkeley National Laboratory (LBNL). Fabrication of the cold mass of the first coupling coil magnet has been completed in China and the cold mass arrived at LBNL in late 2011. Preparations for testing the cold mass are currently under way at Fermilab. Plans for the RFCC module assembly and integration are being developed and are described.

  14. Progress on alternative energy resources

    Science.gov (United States)

    Couch, H. T.

    1982-03-01

    Progress in the year 1981 toward the development of energy systems suitable for replacing petroleum products combustion and growing in use to fulfill a near term expansion in energy use is reviewed. Coal is noted to be a potentially heavy pollution source, and the presence of environmentally acceptable methods of use such as fluidized-bed combustion and gasification and liquefaction reached the prototype stage in 1981, MHD power generation was achieved in two U.S. plants, with severe corrosion problems remaining unsolved for the electrodes. Solar flat plate collectors sales amounted to 20 million sq ft in 1981, and solar thermal electric conversion systems with central receivers neared completion. Solar cells are progressing toward DOE goals of $.70/peak W by 1986, while wind energy conversion sales were 2000 machines in 1981, and the industry is regarded as maturing. Finally, geothermal, OTEC, and fusion systems are reviewed.

  15. Infrastructures of progress and dispossession

    DEFF Research Database (Denmark)

    Andersen, Astrid Oberborbeck

    2016-01-01

    and organizational infrastructural arrangements, it is argued, can open up for understanding how local and beyond-local processes tangle in complex ways and are productive of new subjectivities; how relations are reconfi gured in neoliberal landscapes of progress and dispossession. Such an approach makes evident how...... to reposition small and medium-scale farmers as backward. Th is article analyzes how farmers struggle to fi nd their place within a neoliberal urban ecology where diff erent conceptions of what constitutes progress in contemporary Peru infl uence the landscape. Using an analytical lens that takes material...... and organizational infrastructures and practices into account, and situates these in specifi c historical processes, the article argues that farmers within the urban landscape of Arequipa struggle to reclaim land and water, and reassert a status that they experience to be losing. Such a historical focus on material...

  16. Communication of nuclear data progress

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-15

    This is the 30th issue of Communication of Nuclear Data Progress (CNDP), in which the progress and achievements in nuclear data field in China during 2004 are carried. It includes the evaluations and model calculations of neutron data for n+{sup 31}P, {sup 59}Co, {sup 92-106}Mo, {sup Nat-116}Cd, {sup 233}U and the covariance data evaluation of experimental data for {sup 27}Al, update the decay data for radionuclide {sup 7}Be. Some results of studies for nuclear evaluation tool and model are also included in this issue, i.e. reaction mechanism studies of {sup 5}He, a new method of evaluating the discrepant data, linear fit of correlative data by least squared method et al. (authors)

  17. Progress in Heavy Ion Fusion

    International Nuclear Information System (INIS)

    Herrmannsfeldt, W.B.

    1988-09-01

    The progress of the field of Heavy Ion Fusion has been documented in the proceedings of the series of International Symposia that, in recent years, have occurred every second year. The latest of these conferences was hosted by Gesellshaft fuer Schwerionenforshung (GSI) in Darmstadt, West Germany, June 28-30, 1988. For this report, a few highlights from the conference are selected, stressing experimental progress and prospects for future advances. A little extra time is devoted to report on the developments at the Lawrence Berkeley Laboratory (LBL) which is the center for most of the HIFAR program. The Director of the HIFAR program at LBL is Denis Keefe, who presented the HIF report at the last two of the meetings in this series, and in whose place the author is appearing now. 4 refs., 1 fig

  18. Progressive Supranuclear Palsy: an Update.

    Science.gov (United States)

    Armstrong, Melissa J

    2018-02-17

    Progressive supranuclear palsy (PSP) is a 4R tau neuropathologic entity. While historically defined by the presence of a vertical supranuclear gaze palsy and falls in the first symptomatic year, clinicopathologic studies identify alternate presenting phenotypes. This article reviews the new PSP diagnostic criteria, diagnostic approaches, and treatment strategies. The 2017 International Parkinson and Movement Disorder Society PSP criteria outline 14 core clinical features and 4 clinical clues that combine to diagnose one of eight PSP phenotypes with probable, possible, or suggestive certainty. Evidence supports the use of select imaging approaches in the classic PSP-Richardson syndrome phenotype. Recent trials of putative disease-modifying agents showed no benefit. The new PSP diagnostic criteria incorporating the range of presenting phenotypes have important implications for diagnosis and research. More work is needed to understand how diagnostic evaluations inform phenotype assessment and identify expected progression. Current treatment is symptomatic, but tau-based therapeutics are in active clinical trials.

  19. Communication of nuclear data progress

    International Nuclear Information System (INIS)

    2006-07-01

    This is the 30th issue of Communication of Nuclear Data Progress (CNDP), in which the progress and achievements in nuclear data field in China during 2004 are carried. It includes the evaluations and model calculations of neutron data for n+ 31 P, 59 Co, 92-106 Mo, Nat-116 Cd, 233 U and the covariance data evaluation of experimental data for 27 Al, update the decay data for radionuclide 7 Be. Some results of studies for nuclear evaluation tool and model are also included in this issue, i.e. reaction mechanism studies of 5 He, a new method of evaluating the discrepant data, linear fit of correlative data by least squared method et al. (authors)

  20. PROGRESS IN ACUTE MYELOID LEUKEMIA

    Science.gov (United States)

    Kadia, Tapan M.; Ravandi, Farhad; O’Brien, Susan; Cortes, Jorge; Kantarjian, Hagop M.

    2014-01-01

    Significant progress has been made in the treatment of acute myeloid leukemia (AML). Steady gains in clinical research and a renaissance of genomics in leukemia have led to improved outcomes. The recognition of tremendous heterogeneity in AML has allowed individualized treatments of specific disease entities within the context of patient age, cytogenetics, and mutational analysis. The following is a comprehensive review of the current state of AML therapy and a roadmap of our approach to these distinct disease entities. PMID:25441110

  1. Progress in advanced accelerator concepts

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1994-08-01

    A review is given of recent progress in this field, drawing heavily upon material presented at the Workshop on Advanced Accelerator Concepts, The Abbey, June 12--18, 1994. Attention is addressed to (1) plasma based concepts, (2) photo-cathodes, (3) radio frequency sources and Two-Beam Accelerators, (4) near and far-field schemes (including collective accelerators), (5) beam handling and conditioning, and (6) exotic collider concepts (such as photon colliders and muon colliders)

  2. Revolution and progress in medicine.

    Science.gov (United States)

    Goodwin, William

    2015-02-01

    This paper adapts Kuhn's conceptual framework to developmental episodes in the theory and practice of medicine. Previous attempts to understand the reception of Ignaz Semmelweis's work on puerperal fever in Kuhnian terms are used as a starting point. The author identifies some limitations of these attempts and proposes a new way of understanding the core Kuhnian notions of "paradigm," "progress," and "revolution" in the context of a socially embedded technoscience such as medicine.

  3. Progress in light cone physics

    International Nuclear Information System (INIS)

    Preparata, G.

    1973-01-01

    A very brief review is given of the progress made in the physics of the light cone in the past year. Included are the light cone expansion, gauge invariance and the consequences of precocious scaling near threshold, the light cone description of the muon pair experiment, light cone expansions, and the assessment and exploitation of analyticity properties in both mass and energy of light cone amplitudes. (U.S.)

  4. Gammasphere software development. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Piercey, R.B.

    1994-01-01

    This report describes the activities of the nuclear physics group at Mississippi State University which were performed during 1993. Significant progress has been made in the focus areas: chairing the Gammasphere Software Working Group (SWG); assisting with the porting and enhancement of the ORNL UPAK histogramming software package; and developing standard formats for Gammasphere data products. In addition, they have established a new public ftp archive to distribute software and software development tools and information.

  5. Progress Report. Teilinstitut Nukleare Festkoerperphysik

    International Nuclear Information System (INIS)

    Kaefer, K.

    1978-10-01

    This Progress Report of the Teilinstitut Nukleare Festkoerperphysik covers the work done at the Institute during the period from June 1, 1977 to May 31, 1978. The main research areas presently under investigation are underlined by the arrangement of the report: structure and dynamics of solids, electronic structure and magnetism of solids, and the development and investigation of novel materials. Some technical developments important in carrying out this research are included as well. (orig.) [de

  6. Progress in food irradiation: Australia

    Energy Technology Data Exchange (ETDEWEB)

    Wills, P A

    1982-11-01

    Progress in food irradiation treatment of Australian commodities, such as meat, pepper, honey, fruit is described. Irradiation took place with /sup 60/Co gamma radiation while testing for radiation sensitivity of Staphyllococcus in meat, of Bacillus aureus in pepper, of Streptococcus plutin and Bacillus larvae in honey, and of the fruitfly Dacus tryoni infesting fruit. So far, two State Health Commissions in Australia have authorised irradiation of shrimps with their sale being restricted to the State authorising treatment.

  7. Progress in food irradiation: Australia

    International Nuclear Information System (INIS)

    Wills, P.A.

    1982-01-01

    Progress in food irradiation treatment of Australian commodities, such as meat, pepper, honey, fruit is described. Irradiation took place with 60 Co gamma radiation while testing for radiation sensitivity of Staphyllococcus in meat, of Bacillus aureus in pepper, of Streptococcus plutin and Bacillus larvae in honey, and of the fruitfly Dacus tryoni infesting fruit. Sofar, two State Health Commissions in Australia have authorised irradiation of shrimps with their sale being restricted to the State authorising treatment. (AJ) [de

  8. The 1989 progress report: Mathematics

    International Nuclear Information System (INIS)

    Demazure, M.

    1989-01-01

    The 1989 progress report of the laboratory of Mathematics of the Polytechnic School (France) is presented. The investigations reported were performed in the following fields: analysis of nonlinear partial differential equations, quantum mechanics, scattering, fluid dynamics and homogenization, equations, varieties with negative curvature, elliptical problems on surfaces, Dirac operator, geometry of algorithms and formal calculus, singularities, Lie groups, dynamics systems. The published papers, the conferences and the Laboratory staff are listed [fr

  9. Progressive Taxes and Firm Births

    OpenAIRE

    Hans Ulrich Bacher; Marius Brülhart

    2013-01-01

    Tax reform proposals in the spirit of the 'flat tax' model typically aim to reduce three parameters: the average tax burden, the progressivity of the tax schedule, and the complexity of the tax code. We explore the implications of changes in these three parameters on entrepreneurial activity, measured by counts of firm births. The Swiss fiscal system offers sufficient intra-national variation in tax codes to allow us to estimate these effects with considerable precision. We find that high ave...

  10. NADPH Oxidases: Progress and Opportunities

    OpenAIRE

    San Martin, Alejandra; Griendling, Kathy K.

    2014-01-01

    From the initial discovery in 1999 that NADPH oxidases comprise a family of enzymes to our current focus on drug development to treat multiple pathologies related to this enzyme family, progress has been swift and impressive. We have expanded our understanding of the extent of the family, the basic enzymatic biochemistry, the multiple cellular functions controlled by NADPH oxidases, and their varied roles in physiology and diseases. We have developed numerous cell culture tools, animal models...

  11. Progress Toward Heavy Ion IFE

    International Nuclear Information System (INIS)

    Meier, W.R.; Logan, B.G.; Waldron, W.L.; Sabbi, G.L.; Callahan-Miller, D.A.; Peterson, P.F.; Goodin, D.T.

    2002-01-01

    Successful development of Heavy Ion Fusion (HIF) will require scientific and technology advances in areas of targets, drivers and chambers. Design work on heavy ion targets indicates that high gain (60-130) may be possible with a -3-6 MJ driver depending on the ability to focus the beams to small spot sizes. Significant improvements have been made on key components of heavy ion drivers, including sources, injectors, insulators and ferromagnetic materials for long-pulse induction accelerator cells, solid-state pulsers, and superconducting quadrupole magnets. The leading chamber concept for HIF is the thick-liquid-wall HYLEE-II design, which uses an array of flibe jets to protect chamber structures from x-ray, debris, and neutron damage. Significant progress has been made in demonstrating the ability to create and control the types of flow needed to form the protective liquid blanket. Progress has also been made on neutron shielding for the final focus magnet arrays with predicted lifetimes now exceeding the life of the power plant. Safety analyses have been completed for the HYLEE-II design using state-of-the-art codes. Work also continues on target fabrication and injection for HE. A target injector experiment capable of > 5 Hz operation has been designed and construction will start in 2002. Methods for mass production of hohlraum targets are being evaluated with small-scale experiments and analyses. Progress in these areas will be reviewed

  12. Information Loss from Technological Progress

    International Nuclear Information System (INIS)

    Townsend, P D

    2014-01-01

    Progress in electronics and optics offers faster computers, and rapid communication via the internet that is matched by ever larger and evolving storage systems. Instinctively one assumes that this must be totally beneficial. However advances in software and storage media are progressing in ways which are frequently incompatible with earlier systems and the economics and commercial pressures rarely guarantee total compatibility with earlier systems. Instead, the industries actively choose to force the users to purchase new systems and software. Thus we are moving forward with new technological variants that may have access to only the most recent systems and we will have lost earlier alternatives. The reality is that increased processing speed and storage capacity are matched by an equally rapid decline in the access and survival lifetime of older information. This pattern is not limited to modern electronic systems but is evident throughout history from writing on stone and clay tablets to papyrus and paper. It is equally evident in image systems from painting, through film, to magnetic tapes and digital cameras. In sound recording we have variously progressed from wax discs to vinyl, magnetic tape and CD formats. In each case the need for better definition and greater capacity has forced the earlier systems into oblivion. Indeed proposed interactive music systems could similarly relegate music CDs to specialist collections. The article will track some of the examples and discuss the consequences as well as noting that this information loss is further compounded by developments in language and changes in cultural views of different societies

  13. Information Loss from Technological Progress

    Science.gov (United States)

    Townsend, P. D.

    2014-12-01

    Progress in electronics and optics offers faster computers, and rapid communication via the internet that is matched by ever larger and evolving storage systems. Instinctively one assumes that this must be totally beneficial. However advances in software and storage media are progressing in ways which are frequently incompatible with earlier systems and the economics and commercial pressures rarely guarantee total compatibility with earlier systems. Instead, the industries actively choose to force the users to purchase new systems and software. Thus we are moving forward with new technological variants that may have access to only the most recent systems and we will have lost earlier alternatives. The reality is that increased processing speed and storage capacity are matched by an equally rapid decline in the access and survival lifetime of older information. This pattern is not limited to modern electronic systems but is evident throughout history from writing on stone and clay tablets to papyrus and paper. It is equally evident in image systems from painting, through film, to magnetic tapes and digital cameras. In sound recording we have variously progressed from wax discs to vinyl, magnetic tape and CD formats. In each case the need for better definition and greater capacity has forced the earlier systems into oblivion. Indeed proposed interactive music systems could similarly relegate music CDs to specialist collections. The article will track some of the examples and discuss the consequences as well as noting that this information loss is further compounded by developments in language and changes in cultural views of different societies.

  14. Demyelination versus remyelination in progressive multiple sclerosis

    DEFF Research Database (Denmark)

    Bramow, Stephan; Frischer, Josa M; Lassmann, Hans

    2010-01-01

    The causes of incomplete remyelination in progressive multiple sclerosis are unknown, as are the pathological correlates of the different clinical characteristics of patients with primary and secondary progressive disease. We analysed brains and spinal cords from 51 patients with progressive...... multiple sclerosis by planimetry. Thirteen patients with primary progressive disease were compared with 34 with secondary progressive disease. In patients with secondary progressive multiple sclerosis, we found larger brain plaques, more demyelination in total and higher brain loads of active demyelination...... compared with patients with primary progressive disease. In addition, the brain density of plaques with high-grade inflammation and active demyelination was highest in secondary progressive multiple sclerosis and remained ~18% higher than in primary progressive multiple sclerosis after adjustments...

  15. White Matter Lesion Progression in LADIS

    DEFF Research Database (Denmark)

    Schmidt, Reinhold; Berghold, Andrea; Jokinen, Hanna

    2012-01-01

    BACKGROUND AND PURPOSE: White matter lesion (WML) progression has been advocated as a surrogate marker in intervention trials on cerebral small vessel disease. We assessed the rate of visually rated WML progression, studied correlations between lesion progression and cognition, and estimated sample...... sizes for clinical trials with pure WML progression vs combined WML progression-cognitive outcomes. METHODS: Those 394 participants of the Leukoaraiosis and Disability Study (LADIS) study with magnetic resonance imaging scanning at baseline and 3-year follow-up were analyzed. WML progression rating...

  16. Nuclear theory. 1998 progress report

    International Nuclear Information System (INIS)

    1998-01-01

    Summaries of progress made on the following topics are given: (1) nonresonant contributions to inelastic N→Δ(1232) parity violation; (2) neutron distribution effects in elastic nuclear parity violation; (3) Wilson RG for scalar-plus-fermion field theories at finite density; (4) Perturbation theory for spin ladders using angular momentum coupled bases; (5) mean-field theory for spin ladders using angular momentum density; (6) finite temperature renormalization group effective potentials for the linear Sigma model; (7) negative-parity baryon resonances from lattice QCD; (8) the N→Δ electromagnetic transition amplitudes from QCD sum rules; and (9) higher nucleon resonances in exclusive reactions (γ, πN) on nuclei

  17. Progress of JPDR decommissioning project

    International Nuclear Information System (INIS)

    Kiyota, M.; Yanagihara, S.

    1995-01-01

    The Japan Power Demonstration Reactor (JPDR) decommissioning project is progressively achieving its final goal; the project will be finished by March 1996 to release the JPDR's site into unrestricted use in a green field condition. The new techniques which developed or improved in R and D, the first phase of this program, have been successfully applied to the actual dismantling activities. Some decommissioning wastes have been managed as the first case of onsite shallow land burial based on the new regulatory frame of radioactive waste management. The experiences and the data obtained from the JPDR dismantling activities are expected to contribute to future decommissioning of commercial nuclear power plants. (author)

  18. Nuclear spectroscopic studies. Progress report

    International Nuclear Information System (INIS)

    Bingham, C.R.; Riedinger, L.L.; Sorensen, S.P.

    1996-01-01

    This report describes progress in the experimental nuclear physics program of the University of Tennessee, Knoxville. It presents findings related to properties of high-spin states, low-energy levels of nuclei far from stability, and high-energy heavy-ion physics, as well as a brief description of the Joint Institute of Heavy Ion Research (a collaboration between the University of Tennessee, Vanderbilt University, and Oak Ridge National Laboratory) and its activities (particularly those of the last few years), and a list of publications. 89 refs., 18 figs., 5 tabs

  19. 1995-1996 progress report

    International Nuclear Information System (INIS)

    1997-09-01

    This progress report is mainly devoted to the scientific activity of the LLB or carried out in collaboration with external laboratories. The activity of the LLB is split in several chapters dealing with: magnetism, superconductivity, structures (including lattice dynamics), phase transitions, C 60 , quasi-crystal systems, disordered systems (amorphous, liquids, crystal solid solutions), biology, soft matter (polymers and colloids), physical metallurgy and materials science. Neutron scattering is the main tool used in all these topics but other techniques are also used such as: polarized neutron reflectivity, cold neutrons diffraction, NMR, synchrotron radiation etc. (J.S.)

  20. Biobehavioral Influences on Cancer Progression

    Science.gov (United States)

    Costanzo, Erin S.; Sood, Anil K.; Lutgendorf, Susan K.

    2010-01-01

    Synopsis This review focuses on the contributions of stress-related behavioral factors to cancer growth and metastasis and the biobehavioral mechanisms underlying these relationships. We describe behavioral factors that are important in modulation of the stress response and the pivotal role of neuroendocrine regulation in the downstream alteration of physiological pathways relevant to cancer control, including the cellular immune response, inflammation, and tumor angiogenesis, invasion, and cell-signaling pathways. Consequences for cancer progression and metastasis, as well as quality of life, are delineated. Finally, behavioral and pharmacological interventions for cancer patients with the potential to alter these biobehavioral pathways are discussed. PMID:21094927