176 research outputs found
PARĂSITOS INTESTINALES Y SU DIAGNĂSTICO
Las técnicas moleculares, como la reacción en cadena de la polimerasa (PCR) pueden ser aplicadas al campo de las ciencias médicas para diagnosticar la presencia de agentes infecciosos
Functional evolution of the Colony Stimulating Factor 1 Receptor (CSF1R) and its ligands in birds
Macrophage colonyâstimulating factor (CSF1 or MâCSF) and interleukin 34 (IL34) are secreted cytokines that control macrophage survival and differentiation. Both act through the CSF1 receptor (CSF1R), a type III transmembrane receptor tyrosine kinase. The functions of CSF1R and both ligands are conserved in birds. We have analyzed proteinâcoding sequence divergence among avian species. The intracellular tyrosine kinase domain of CSF1R was highly conserved in bird species as in mammals but the extracellular domain of avian CSF1R was more divergent in birds with multiple positively selected amino acids. Based upon crystal structures of the mammalian CSF1/IL34 receptorâligand interfaces and structureâbased alignments, we identified amino acids involved in avian receptorâligand interactions. The contact amino acids in both CSF1 and CSF1R diverged among avian species. Ligandâbinding domain swaps between chicken and zebra finch CSF1 confirmed the function of variants that confer species specificity on the interaction of CSF1 with CSF1R. Based upon genomic sequence analysis, we identified prevalent amino acid changes in the extracellular domain of CSF1R even within the chicken species that distinguished commercial broilers and layers and tropically adapted breeds. The rapid evolution in the extracellular domain of avian CSF1R suggests that at least in birds this ligandâreceptor interaction is subjected to pathogen selection. We discuss this finding in the context of expression of CSF1R in antigenâsampling and antigenâpresenting cells.UK Government's Department for International Development. Grant Number: OPP112728
VariaciĂłn intraespecĂfica e individual de los pelos de mamĂferos del Estado de MĂ©xico: implicaciones en la identificaciĂłn interespecĂfica
Se determinĂł la variaciĂłn del pelo de guardia dorsal entre individuos de la misma especie y se comparĂł la variaciĂłn de un individuo en diferentes regiones. Se midiĂł la longitud total y diĂĄmetro de la mĂ©dula, ademĂĄs se determinĂł el patrĂłn de tonalidad y tipo de mĂ©dula. En la comparaciĂłn intraespecĂfica se caracterizaron 530 pelos de guardia dorsales de 53 organismos. A pesar de las variaciones en la longitud y diĂĄmetro de la mĂ©dula, puede realizarse una identificaciĂłn exitosa de los organismos en un plano especĂfico utilizando la guĂa de identificaciĂłn de mamĂferos terrestres a partir del pelo de guardia, excepto para Canis latrans y Liomys irroratus. En la comparaciĂłn individual se describieron 560 pelos de guardia de 14 especies. Se encontraron diferencias en la longitud total del pelo, en el diĂĄmetro de la mĂ©dula y en la coloraciĂłn; el Ășnico carĂĄcter que permaneciĂł constante fue la mĂ©dula.Se determinĂł la variaciĂłn del pelo de guardia dorsal entre individuos de la misma especie y se comparĂł la variaciĂłn de un individuo en diferentes regiones. Se midiĂł la longitud total y diĂĄmetro de la mĂ©dula, ademĂĄs se determinĂł el patrĂłn de tonalidad y tipo de mĂ©dula. En la comparaciĂłn intraespecĂfica se caracterizaron 530 pelos de guardia dorsales de 53 organismos. A pesar de las variaciones en la longitud y diĂĄmetro de la mĂ©dula, puede realizarse una identificaciĂłn exitosa de los organismos en un plano especĂfico utilizando la guĂa de identificaciĂłn de mamĂferos terrestres a partir del pelo de guardia, excepto para Canis latrans y Liomys irroratus. En la comparaciĂłn individual se describieron 560 pelos de guardia de 14 especies. Se encontraron diferencias en la longitud total del pelo, en el diĂĄmetro de la mĂ©dula y en la coloraciĂłn; el Ășnico carĂĄcter que permaneciĂł constante fue la mĂ©dula
Klhl31 attenuates ÎČ-catenin dependent Wnt signaling and regulates embryo myogenesis
Klhl31 is a member of the Kelch-like family in vertebrates, which are characterized by an amino-terminal broad complex tram-track, bric-a-brac/poxvirus and zinc finger (BTB/POZ) domain, carboxy-terminal Kelch repeats and a central linker region (Back domain). In developing somites Klhl31 is highly expressed in the myotome downstream of myogenic regulators (MRF), and it remains expressed in differentiated skeletal muscle. In vivo gain- and loss-of-function approaches in chick embryos reveal a role of Klhl31 in skeletal myogenesis. Targeted mis-expression of Klhl31 led to a reduced size of dermomyotome and myotome as indicated by detection of relevant myogenic markers, Pax3, Myf5, myogenin and myosin heavy chain (MF20). The knock-down of Klhl31 in developing somites, using antisense morpholinos (MO), led to an expansion of Pax3, Myf5, MyoD and myogenin expression domains and an increase in the number of mitotic cells in the dermomyotome and myotome. The mechanism underlying this phenotype was examined using complementary approaches, which show that Klhl31 interferes with ÎČ-catenin dependent Wnt signaling. Klhl31 reduced the Wnt-mediated activation of a luciferase reporter in cultured cells. Furthermore, Klhl31 attenuated secondary axis formation in Xenopus embryos in response to Wnt1 or ÎČ-catenin. Klhl31 mis-expression in the developing neural tube affected its dorso-ventral patterning and led to reduced dermomyotome and myotome size. Co-transfection of a Wnt3a expression vector with Klhl31 in somites or in the neural tube rescued the phenotype and restored the size of dermomyotome and myotome. Thus, Klhl31 is a novel modulator of canonical Wnt signaling, important for vertebrate myogenesis. We propose that Klhl31 acts in the myotome to support cell cycle withdrawal and differentiation
Functional evolution of the colonyâstimulating factor 1 receptor (CSF1R) and its ligands in birds
Macrophage colony-stimulating factor (CSF1 or M-CSF) and interleukin 34 (IL34) are secreted cytokines that control macrophage survival and differentiation. Both act through the CSF1 receptor (CSF1R), a type III transmembrane receptor tyrosine kinase. The functions of CSF1R and both ligands are conserved in birds. We have analyzed protein-coding sequence divergence among avian species. The intracellular tyrosine kinase domain of CSF1R was highly conserved in bird species as in mammals but the extracellular domain of avian CSF1R was more divergent in birds with multiple positively selected amino acids. Based upon crystal structures of the mammalian CSF1/IL34 receptor-ligand interfaces and structure-based alignments, we identified amino acids involved in avian receptor-ligand interactions. The contact amino acids in both CSF1 and CSF1R diverged among avian species. Ligand-binding domain swaps between chicken and zebra finch CSF1 confirmed the function of variants that confer species specificity on the interaction of CSF1 with CSF1R. Based upon genomic sequence analysis, we identified prevalent amino acid changes in the extracellular domain of CSF1R even within the chicken species that distinguished commercial broilers and layers and tropically adapted breeds. The rapid evolution in the extracellular domain of avian CSF1R suggests that at least in birds this ligand-receptor interaction is subjected to pathogen selection. We discuss this finding in the context of expression of CSF1R in antigen-sampling and antigen-presenting cells
Functional evolution of the colonyâstimulating factor 1 receptor (CSF1R) and its ligands in birds
Macrophage colony-stimulating factor (CSF1 or M-CSF) and interleukin 34 (IL34) are secreted cytokines that control macrophage survival and differentiation. Both act through the CSF1 receptor (CSF1R), a type III transmembrane receptor tyrosine kinase. The functions of CSF1R and both ligands are conserved in birds. We have analyzed protein-coding sequence divergence among avian species. The intracellular tyrosine kinase domain of CSF1R was highly conserved in bird species as in mammals but the extracellular domain of avian CSF1R was more divergent in birds with multiple positively selected amino acids. Based upon crystal structures of the mammalian CSF1/IL34 receptor-ligand interfaces and structure-based alignments, we identified amino acids involved in avian receptor-ligand interactions. The contact amino acids in both CSF1 and CSF1R diverged among avian species. Ligand-binding domain swaps between chicken and zebra finch CSF1 confirmed the function of variants that confer species specificity on the interaction of CSF1 with CSF1R. Based upon genomic sequence analysis, we identified prevalent amino acid changes in the extracellular domain of CSF1R even within the chicken species that distinguished commercial broilers and layers and tropically adapted breeds. The rapid evolution in the extracellular domain of avian CSF1R suggests that at least in birds this ligand-receptor interaction is subjected to pathogen selection. We discuss this finding in the context of expression of CSF1R in antigen-sampling and antigen-presenting cells
Cell-Autonomous Sex Differences in Gene Expression in Chicken Bone Marrow-Derived Macrophages
We have identified differences in gene expression in macrophages grown from the bone marrow of male and female chickens in recombinant chicken M-CSF (CSF1). Cells were profiled with or without treatment with bacterial LPS for 24 h. Approximately 600 transcripts were induced by prolonged LPS stimulation to an equal extent in the male and female macrophages. Many transcripts encoded on the Z chromosome were expressed âŒ1.6-fold higher in males, reflecting a lack of dosage compensation in the homogametic sex. A smaller set of W chromosome-specific genes was expressed only in females. LPS signaling in mammals is associated with induction of type 1 IFN-responsive genes. Unexpectedly, because IFNs are encoded on the Z chromosome of chickens, unstimulated macrophages from the female birds expressed a set of known IFN-inducible genes at much higher levels than male cells under the same conditions. To confirm that these differences were not the consequence of the actions of gonadal hormones, we induced gonadal sex reversal to alter the hormonal environment of the developing chick and analyzed macrophages cultured from male, female, and female sex-reversed embryos. Gonadal sex reversal did not alter the sexually dimorphic expression of either sex-linked or IFN-responsive genes. We suggest that female birds compensate for the reduced dose of inducible IFN with a higher basal set point of IFN-responsive genes
Standalone vertex ïŹnding in the ATLAS muon spectrometer
A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at âs = 7 TeV collected with the ATLAS detector at the LHC during 2011
Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC
Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H âÎł Îł, H â Z Zâ â4l and H âW Wâ âlÎœlÎœ. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of âs = 7 TeV and âs = 8 TeV, corresponding to an integrated luminosity of about 25 fbâ1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined ïŹts probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson
Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV
A measurement of the production cross-section for top quark pairs(\ttbar)
in collisions at \sqrt{s}=7 \TeV is presented using data recorded with
the ATLAS detector at the Large Hadron Collider. Events are selected in two
different topologies: single lepton (electron or muon ) with large
missing transverse energy and at least four jets, and dilepton (,
or ) with large missing transverse energy and at least two jets. In a
data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton
topology and 9 events in the dilepton topology. The corresponding expected
backgrounds from non-\ttbar Standard Model processes are estimated using
data-driven methods and determined to be events and events, respectively. The kinematic properties of the selected events are
consistent with SM \ttbar production. The inclusive top quark pair production
cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where
the first uncertainty is statistical and the second systematic. The measurement
agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables,
CERN-PH number and final journal adde
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