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Search Results: 1 - 10 of 570 matches for " Agata Rybarska "
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GLS-1, a Novel P Granule Component, Modulates a Network of Conserved RNA Regulators to Influence Germ Cell Fate Decisions
Agata Rybarska,Martin Harterink,Britta Jedamzik,Adam P. Kupinski,Mark Schmid,Christian R. Eckmann
PLOS Genetics , 2009, DOI: 10.1371/journal.pgen.1000494
Abstract: Post-transcriptional regulatory mechanisms are widely used to influence cell fate decisions in germ cells, early embryos, and neurons. Many conserved cytoplasmic RNA regulatory proteins associate with each other and assemble on target mRNAs, forming ribonucleoprotein (RNP) complexes, to control the mRNAs translational output. How these RNA regulatory networks are orchestrated during development to regulate cell fate decisions remains elusive. We addressed this problem by focusing on Caenorhabditis elegans germline development, an exemplar of post-transcriptional control mechanisms. Here, we report the discovery of GLS-1, a new factor required for many aspects of germline development, including the oocyte cell fate in hermaphrodites and germline survival. We find that GLS-1 is a cytoplasmic protein that localizes in germ cells dynamically to germplasm (P) granules. Furthermore, its functions depend on its ability to form a protein complex with the RNA-binding Bicaudal-C ortholog GLD-3, a translational activator and P granule component important for similar germ cell fate decisions. Based on genetic epistasis experiments and in vitro competition experiments, we suggest that GLS-1 releases FBF/Pumilio from GLD-3 repression. This facilitates the sperm-to-oocyte switch, as liberated FBF represses the translation of mRNAs encoding spermatogenesis-promoting factors. Our proposed molecular mechanism is based on the GLS-1 protein acting as a molecular mimic of FBF/Pumilio. Furthermore, we suggest that a maternal GLS-1/GLD-3 complex in early embryos promotes the expression of mRNAs encoding germline survival factors. Our work identifies GLS-1 as a fundamental regulator of germline development. GLS-1 directs germ cell fate decisions by modulating the availability and activity of a single translational network component, GLD-3. Hence, the elucidation of the mechanisms underlying GLS-1 functions provides a new example of how conserved machinery can be developmentally manipulated to influence cell fate decisions and tissue development.
In Vivo Colocalisation of oskar mRNA and Trans-Acting Proteins Revealed by Quantitative Imaging of the Drosophila Oocyte
Musa M. Mhlanga, Diana P. Bratu, Auguste Genovesio, Agata Rybarska, Nicolas Chenouard, Ulf Nehrbass, Jean-Christophe Olivo-Marin
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0006241
Abstract: Efficient mRNA transport in eukaryotes requires highly orchestrated relationships between nuclear and cytoplasmic proteins. For oskar mRNA, the Drosophila posterior determinant, these spatio-temporal requirements remain opaque during its multi-step transport process. By in vivo covisualization of oskar mRNA with Staufen, its putative trafficking protein, we find oskar mRNA to be present in particles distinct from Staufen for part of its transport. oskar mRNA stably associated with Staufen near the posterior pole. We observe oskar mRNA to oligomerize as hundreds of copies forming large particles which are necessary for its long range transport and localization. We show the formation of these particles occurs in the nurse cell nucleus in an Hrp48-dependent manner. We present a more refined model of oskar mRNA transport in the Drosophila oocyte.
Dijet correlations in $pp$ collisions at RHIC
Szczurek, A.;Rybarska, A.;Slipek, G.
High Energy Physics - Phenomenology , 2007,
Abstract: We compare results of $k_t$-factorization approach and next-to-leading order collinear-factorization approach for dijet correlations in proton-proton collisions at RHIC energies. We discuss correlations in azimuthal angle as well as correlations in two-dimensional space of transverse momenta of two jets. Some $k_t$-factorization subprocesses are included for the first time in the literature. Different unintegrated gluon/parton distributions are used in the $k_t$-factorization approach. The results depend on UGDF/UPDF used. Limitations due to leading jet condition are discussed.
Exclusive J/psi photoproduction in pp and ppbar collisions
Rybarska, Anna;Sch fer, Wolfgang;Szczurek, Antoni
High Energy Physics - Phenomenology , 2008,
Abstract: We report on a detailed investigation of exclusive J/psi production in proton--proton and proton-antiproton collisions. Predictions for Tevatron and LHC energies are included.
Dijet correlations at RHIC, leading-order $k_t$-factorization approach versus next-to-leading order collinear approach
Szczurek, Antoni;Rybarska, Anna;Slipek, Gabriela
High Energy Physics - Phenomenology , 2007, DOI: 10.1103/PhysRevD.76.034001
Abstract: We compare results of $k_t$-factorization approach and next-to-leading order collinear-factorization approach for dijet correlations in proton-proton collisions at RHIC energies. We discuss correlations in azimuthal angle as well as correlations in two-dimensional space of transverse momenta of two jets. Some $k_t$-factorization subprocesses are included for the first time in the literature. Different unintegrated gluon/parton distributions are used in the $k_t$-factorization approach. The results depend on UGDF/UPDF used. For collinear NLO case the situation depends significantly on whether we consider correlations of any two jets or correlations of leading jets only. In the first case the $2 \to 2$ contributions associated with soft radiations summed up in the $k_t$-factorization approach dominate at $\phi \sim \pi$ and at equal moduli of jet transverse momenta. The collinear NLO $2 \to 3$ contributions dominate over $k_t$-factorization cross section at small relative azimuthal angles as well as for asymmetric transverse momentum configurations. In the second case the NLO contributions vanish at small relative azimuthal angles and/or large jet transverse-momentum disbalance due to simple kinematical constraints. There are no such limitations for the $k_t$-factorization approach. All this makes the two approaches rather complementary. The role of several cuts is discussed and quantified.
Exclusive Upsilon-photoproduction: from HERA to Tevatron
Rybarska, Anna;Sch fer, Wolfgang;Szczurek, Antoni
High Energy Physics - Phenomenology , 2008,
Abstract: The amplitude for photoproduction gamma p -> \Upsilon p is calculated in a pQCD k_\perp-factorization approach. The total cross section for diffractive \Upsilon's is compared to recent HERA data. The amplitude is used to predict the cross section for exclusive ppbar \to ppbar \Upsilon(1S,2S) process in hadronic reactions at Tevatron energies. We also included absorption effects.
Decomposition of Topologies Which Characterize the Upper and Lower Semicontinuous Limits of Functions
Agata Caserta
Abstract and Applied Analysis , 2011, DOI: 10.1155/2011/857278
Abstract: We present a decomposition of two topologies which characterize the upper and lower semicontinuity of the limit function to visualize their hidden and opposite roles with respect to the upper and lower semicontinuity and consequently the continuity of the limit. We show that (from the statistical point of view) there is an asymmetric role of the upper and lower decomposition of the pointwise convergence with respect to the upper and lower decomposition of the sticking convergence and the semicontinuity of the limit. This role is completely hidden if we use the whole pointwise convergence. Moreover, thanks to this mirror effect played by these decompositions, the statistical pointwise convergence of a sequence of continuous functions to a continuous function in one of the two symmetric topologies, which are the decomposition of the sticking topology, automatically ensures the convergence in the whole sticking topology. 1. Introduction Since the end of the nineteenth century several outstanding papers appeared to formulate a set of conditions, which are both necessary and sufficient, to be added to pointwise convergence of a sequence of continuous functions, to preserve continuity of the limit. Indeed, all classical kinds of convergences of sequences of functions between metric spaces (Dini, Arzelà, Alexandroff) are based on the pointwise convergence assumption that has been always considered a preliminary one. Recently, in [1, 2], Caserta et al. proposed a new model to investigate convergences in function spaces: the statistical one. Actually, they obtained results parallel to the classical ones, concerning the continuity of the limit, in spite of the fact that statistical convergence has a minor control of the whole set of functions. In [2] they proved that continuity of the limit of a sequence of functions is equivalent to several modes of statistical convergence which are similar, but weaker than the classical ones. A parallel to the classical results is expected since, after all, in [3] the authors found the statistical convergence to be the same as a very special regular triangular matrix summability method for bounded (and some unbounded) sequences. Thus many new results concerning statistical convergence follow from the corresponding known results for matrix summability. In 1969 Bouleau [4, 5] defined the sticking topology as the weakest topology finer than pointwise convergence to preserve continuity. In [6], Beer presented two new topologies on , finer than the topology of pointwise convergence, which are indeed the decomposition of the sticking
Book Review: Medicina, historia y género. 130 a os de investigación feminista, by Teresa Ortiz Gómez
Agata Ignaciuk
Graduate Journal of Social Science , 2010,
Abstract:
Objawy laryngologiczne choroby refluksowej prze yku u dzieci w wieku szkolnym
Agata Szlachcic
Pediatria Wspó?czesna , 2010,
Abstract: Wprowadzenie: Choroba refluksowa prze yku u dzieci mo e przybiera tzw. mask laryngologiczn i w ramach tej postaci objawy ze strony przewodu pokarmowego mog nie wyst powa . Cel pracy: Okre lenie cz sto ci wyst powania wybranych objawów laryngologicznych u dzieci w wieku szkolnym z chorob refluksow prze yku, ich zale no ci od nasilenia refluksu kwa nego i jego obecno ci w dolnej i górnej cz ci prze yku oraz ocena zmian zapalnych krtani w badaniu wideostroboskopowym. Materia i metody: Analiz obj to 194 dzieci w wieku od 6 do 18 lat hospitalizowanych w klinice z podejrzeniem choroby refluksowej prze yku. U ka dego pacjenta przeprowadzono dok adny wywiad dotycz cy objawów laryngologicznych oraz wykonano 24-godzinn pH-metri prze yku, na podstawie której pacjentów podzielono na 3 grupy z ró nym nasileniem patologicznego refluksu kwa nego oraz na grup kontroln z prawid owym wynikiem badania. Ponadto wyodr bniono grupy z obecno ci i bez kwa nego refluksu w górnej cz ci prze yku. Ponadto u 34 dzieci wykonano badanie wideostroboskopowe krtani. Wykorzystuj c metody statystyczne porównano wyst powanie objawów laryngologicznych w wymienionych grupach. Wyniki: Najcz stszymi objawami laryngologicznymi zg aszanymi przez pacjentów z chorob refluksow prze yku by y: chrypka (31,8%), chrz kanie (28,6%), bóle gard a (27,4%). Wraz z nasileniem choroby refluksowej prze yku wzrasta a cz sto wyst powania chrz kania u dzieci z 25% w postaci agodnej, do 31,5% przy ci kim refluksie. Na bóle gard a i uczucie cia a obcego w gardle znamiennie cz ciej skar yli si pacjenci z mniejszym nasileniem choroby refluksowej, ni z jej ci sz postaci . U pacjentów, u których stwierdzono obecno refluksu w górnej cz ci prze yku (podgrupa B) cz ciej wyst powa y takie objawy z uk adu oddechowego, jak: chrz kanie, chrypka, suchy kaszel, uczucie cia a obcego w gardle. Zmiany zapalne krtani w postaci obrz ku strun g osowych oraz owrzodzenia kontaktowego stwierdzono jedynie u dzieci z chorob refluksow prze yku. Obecno kwa nego refluksu w górnej cz ci prze yku sprzyja a cz stszemu wyst powaniu obrz ku strun g osowych, owrzodzenia kontaktowego w obr bie krtani oraz zapaleniu tchawicy. Wnioski: 1. Objawy laryngologiczne cz sto wyst puj w przebiegu choroby refluksowej prze yku u dzieci w wieku szkolnym. 2. Najcz stszymi objawami by y: chrypka, chrz kanie, bóle gard a. 3. Cz sto wyst powania objawów laryngologicznych wzrasta przy obecno ci wysokiego refluksu o dkowo-prze ykowego. 4. Obrz k strun g osowych oraz owrzodzenia kontaktowe w badaniu wideostroboskopowym obserwowa
Wp yw choroby refluksowej prze yku na wyst powanie nawracaj cych infekcji dróg oddechowych oraz astmy oskrzelowej u dzieci w wieku szkolnym
Agata Szlachcic
Pediatria Wspó?czesna , 2010,
Abstract: Wprowadzenie: W ostatnich latach coraz wi ksz rol w obrazie klinicznym choroby refluksowej prze yku odgrywaj objawy pozaprze ykowe, a szczególnie objawy pochodz ce z uk adu oddechowego. Cel pracy: Okre lenie rodzaju i cz sto ci wyst powania nawracaj cych infekcji dróg oddechowych oraz astmy oskrzelowej u dzieci w wieku szkolnym z chorob refluksow prze yku, ich zale no ci od nasilenia patologicznego refluksu kwa nego i jego obecno ci w dolnej i górnej cz ci prze yku. Materia i metodyka: Analiz obj to 194 dzieci w wieku od 6 do 18 lat hospitalizowanych w Klinice z podejrzeniem choroby refluksowej prze yku. U ka dego pacjenta przeprowadzono dok adny wywiad dotycz cy chorób uk adu oddechowego oraz wykonano 24-godzinn pH-metri prze yku, na podstawie której pacjentów podzielono na 3 grupy z ró nym nasileniem patologicznego refluksu kwa nego oraz na grup kontroln z prawid owym wynikiem badania. Ponadto wyodr bniono grupy z obecno ci i bez kwa nego refluksu w górnej cz ci prze yku. Wykorzystuj c metody statystyczne porównano wyst powanie infekcji dróg oddechowych i astmy oskrzelowej w wymienionych grupach. Wyniki: Dzieci z chorob refluksow prze yku najcz ciej chorowa y na nawracaj ce zapalenia oskrzeli (25,5%) oraz gard a (24,2%). Wraz z nasileniem choroby refluksowej prze yku u dzieci wzrasta a cz sto wyst powania nawracaj cych zapaleń gard a oraz zatok obocznych nosa. Pacjenci, u których stwierdzono obecno refluksu w górnej cz ci prze yku znamiennie cz ciej chorowali na nawracaj ce zapalenia zatok obocznych nosa, zapalenia oskrzeli oraz astm oskrzelow . Pacjenci z prawid owym badaniem pH-metrycznym istotnie cz ciej chorowali na nawracaj ce zapalenia gard a i ucha rodkowego, co sugeruje inn ni choroba refluksowa przyczyn tych infekcji. Wnioski: 1. Badane dzieci najcz ciej chorowa y na nawracaj ce zapalenia oskrzeli oraz gard a. 2. Stopień nasilenia choroby refluksowej prze yku istotnie wp ywa na cz ste wyst powanie zapaleń gard a u dzieci. 3. Obecno patologicznego refluksu w górnej cz ci prze yku znamiennie wp ywa a na wyst powanie nawracaj cych zapaleń zatok, oskrzeli oraz astmy oskrzelowej u badanych dzieci. 4. Choroba refluksowa prze yku by a tylko jedn z przyczyn nawracaj cych zapaleń gard a i ucha rodkowego.
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