738 research outputs found

    CTCF: A Crucial Regulator of Gene Expression in Lymphocytes

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    In vertebrates, the immune system is responsible for the protection against pathogens such as viruses, bacteria, fungi or parasites. This remarkably effective defense system depends upon the white blood cells or leukocytes, which mediate both innate and adaptive immune responses. Innate immunity provides an immediate but non-specific front line of host defense against many pathogens and involves granulocytes (neutrophils, eosinophils and basophils), mast cells, macrophages and natural killer (NK) cells. Germ lineencoded surface receptors to common pathogens constituents on innate effector cells trigger the elimination of pathogens by phagocytosis and the release of inflammatory mediators, such as cytokines and chemokines. These receptors are referred to as pattern recognition receptors (PRRs), which recognize a limited set of molecules that are broadly shared by pathogens but distinguishable from host molecules, collectively referred to as pathogen-associated molecular patterns (PAMPs). Acquired or adaptive immunity is characterized by gradual, though highly specific and effective immune responses against pathogens. Three major cell types are involved in adaptive immunity: B-lymphocytes, T-lymphocytes and antigen presenting cells (APCs), the most potent of which are dendritic cells (DCs). DCs act as messengers between the innate and adaptive immune system. Their main function is to take up, process and present pathogen constituents (also called antigens) with major histocompatibility complex (MHC) proteins to T lymphocytes. B- and T-lymphocytes are considered to be the central players of the adaptive immune system. Their unique and virtually limitless capacity to specifically recognize antigens relies on the generation of a wide repertoire of antigen receptors – B-cell receptor (BCR) in B-lymphocytes and T-cell receptor (TCR) in T-lymphocytes –

    Lentiviral-mediated delivery of mutant huntingtin in the striatum of rats induces a selective neuropathology modulated by polyglutamine repeat size, huntingtin expression levels, and protein length.

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    A new strategy based on lentiviral-mediated delivery of mutant huntingtin (htt) was used to create a genetic model of Huntington's disease (HD) in rats and to assess the relative contribution of polyglutamine (CAG) repeat size, htt expression levels, and protein length on the onset and specificity of the pathology. Lentiviral vectors coding for the first 171, 853, and 1520 amino acids of wild-type (19 CAG) or mutant htt (44, 66, and 82 CAG) driven by either the phosphoglycerate kinase 1 (PGK) or the cytomegalovirus (CMV) promoters were injected in rat striatum. A progressive pathology characterized by sequential appearance of ubiquitinated htt aggregates, loss of dopamine- and cAMP-regulated phosphoprotein of 32 kDa staining, and cell death was observed over 6 months with mutant htt. Earlier onset and more severe pathology occurred with shorter fragments, longer CAG repeats, and higher expression levels. Interestingly, the aggregates were predominantly located in the nucleus of PGK-htt171-injected rats, whereas they were present in both the nucleus and processes of CMV-htt171-injected animals expressing lower transgene levels. Finally, a selective sparing of interneurons was observed in animals injected with vectors expressing mutant htt. These data demonstrate that lentiviral-mediated expression of mutant htt provides a robust in vivo genetic model for selective neural degeneration that will facilitate future studies on the pathogenesis of cell death and experimental therapeutics for HD

    Estado Da Arte Da Literatura Científica Sobre Hancornia Speciosa: Tendências E Lacunas

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    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The economic and scientific interest in Hancornia speciosa (mangabeira) has been growing in recent years, mainly due to the marketing of fruit and extraction of natural compounds with high pharmacological potential. In this study, a scientometric survey about mangabeira was carried out in order to promote and direct future studies on the species. As a result, low scientific productivity associated with this species was found, with only 131 articles published in the last 69 years. In addition, this study identified some trends in bibliographic production on mangabeira, among them: the increasing number of articles over the years; scientific dissemination in nationwide journals; the main focus of this study is associated with agronomic studies; the experimental approach is more frequent and usually associated with populations of restricted geographical distribution; and the scientific production is mainly from education institutions. Furthermore, this study also allowed the identification of some gaps in knowledge about mangabeira, among them the difficulty in describing and characterizing botanical lines; lack of analysis of the genetic diversity of widely distributed populations; lack of management and conservation projects for the species; lack of description of cultivation, collection and preservation techniques of fruits; and lack of identification of natural compounds responsible for its pharmacological activity. It is expected that the data generated in this study will serve to direct future studies on H. speciosa. © 2016, Sociedade Brasileira de Fruticultura. All rights reserved.384CAPES, Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorCNPq, Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPEG, Fundação de Amparo à Pesquisa do Estado de GoiásFINEP, Financiadora de Estudos e ProjetosCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Magnetic And Superconducting Properties Of Ru Sr2 Gd1.5 Ce0.5 Cu2 O10-δ Samples: Dependence On The Oxygen Content And Aging Effects

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    The magnetic and superconducting properties of Ru Sr2 Gd1.5 Ce0.5 Cu2 O10-δ polycrystalline samples with different oxygen-doping levels are presented. A strong suppression of the superconducting temperature (Tc), as well as a reduction in the superconducting fraction, occurs as the oxygen content is reduced by annealing the samples in oxygen-deprived atmospheres. Drastic changes in the electrical resistivity are observed above Tc, possibly associated with oxygen removal, mainly from grain boundaries. However, the magnetic ordering is relatively less affected by the changes in oxygen content of the samples. The spin-glass transition is enhanced and shifted to higher temperatures with the reduction in oxygen content. This could be correlated with an increase in the spin disorder and frustration for the oxygen-depleted samples. Also, the same oxygen-vacancy-induced disorder could explain the reduction in the fraction of the sample showing antiferromagnetic order. We also report significant changes in the measured properties of the samples as a function of time. © 2005 The American Physical Society.7113Felner, I., Asaf, U., Levi, Y., Millo, O., (1997) Phys. Rev. B, 55, p. 3374. , PRBMDO 0163-1829 10.1103/PhysRevB.55.R3374Bernhard, C., Tallon, J.L., Niedermayer, Ch., Blasius, Th., Golnik, A., Brücher, E., Kremer, R.K., Ansaldo, E.J., (1999) Phys. Rev. B, 59, p. 14099. , PRBMDO. 0163-1829. 10.1103/PhysRevB.59.14099Awana, V.P.S., Karppinen, M., Yamauchi, H., (2003) Studies of High Tc Superconductors, 46, p. 77. , edited by A. V. Narlikar (Nova Science Publishers, New YorkMatvejeff, M., Awana, V.P.S., Jang, L.-Y., Liu, R.S., Yamauchi, H., Karppinen, M., (2003) Physica C, 392-396, p. 87. , PHYCE6 0921-4534Cardoso, C.A., Araujo-Moreira, F.M., Awana, V.P.S., Kishan, H., Takayama-Muromachi, E., De Lima, O.F., (2004) Physica C, 405, p. 212. , PHYCE6 0921-4534Cardoso, C.A., Araujo-Moreira, F.M., Awana, V.P.S., Takayama-Muromachi, E., De Lima, O.F., Yamauchi, H., Karppinen, M., (2003) Phys. Rev. B, 67, p. 020407. , PRBMDO 0163-1829 10.1103/PhysRevB.67.020407Shi, L., Li, G., Fan, X.J., Feng, S.J., Li, X.-G., (2003) Physica C, 399, p. 69. , PHYCE6 0921-4534Felner, I., Asaf, U., Ritter, F., Klamut, P.W., Dabrowski, B., (2001) Physica C, 364-365, p. 368. , PHYCE6 0921-4534Felner, I., Asaf, U., Galstyan, E., (2002) Phys. Rev. B, 66, p. 024503. , PRBMDO 0163-1829 10.1103/PhysRevB.66.024503Felner, I., Asaf, U., Levi, Y., Millo, O., (2000) Physica C, 334, p. 141. , PHYCE6 0921-4534 10.1016/S0921-4534(00)00250-1Awana, V.P.S., Ansari, M.A., Gupta, A., Saxena, R.B., Kishan, H., Buddhikot, D., Malik, S.K., (2004) Phys. Rev. B, 70, p. 104520. , PRBMDO 0163-1829 10.1103/PhysRevB.70.104520Yoshizawa, H., Mitsuda, S., Aruga, H., Ito, A., (1987) Phys. Rev. Lett., 59, p. 2364. , PRLTAO 0031-9007 10.1103/PhysRevLett.59.2364Binder, K., Young, A.P., (1986) Rev. Mod. Phys., 58, p. 801. , RMPHAT 0034-6861 10.1103/RevModPhys.58.801Mydosh, J.A., (1993) Spin Glasses An Experimental Introduction, , Taylor & Francis, LondonFelner, I., Galstyan, E., Herber, R.H., Nowik, I., (2004) Phys. Rev. B, 70, p. 094504. , PRBMDO 0163-1829 10.1103/PhysRevB.70.094504Shengelaya, A., Khasanov, R., Eschenko, D.G., Felner, I., Asaf, U., Savić, I.M., Keller, H., Müller, K.A., (2004) Phys. Rev. B, 69, p. 024517. , PRBMDO. 0163-1829. 10.1103/PhysRevB.69.024517Xue, Y.Y., Cao, D.H., Lorenz, B., Chu, C.W., (2002) Phys. Rev. B, 65, p. 020511. , PRBMDO 0163-1829 10.1103/PhysRevB.65.02051

    Failure of sexing by developmental arrest of bovine embryos in vitro produced with H-Y antisera

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    Embriões bovinos produzidos in vitro, em estádio de mórula, foram cultivados em meio contendo anticorpos anti H-Y de alto título proveniente de ratos por 24h e, após este tempo, classificados em dois grupos: 1) embriões inibidos em estádio de mórula (classificados como machos) e 2) embriões que se desenvolveram e formaram a blastocele (classificados como fêmeas). O sexo de 311 embriões, distribuídos em três grupos de concentração dos anticorpos, 3%, 5% ou 7%, foi identificado pela reação em cadeia da polimerase. Não houve desvio da proporção entre machos e fêmeas (P>0,05) nos grupos em que se utilizaram os anticorpos anti H-Y, quando comparadas ao grupo-controle, sem adição de anticorpos anti H-Y. Diferentemente dos resultados obtidos utilizando-se embriões bovinos produzidos in vivo, a sexagem com anticorpos anti H-Y de alto título em embriões produzidos in vitro não propiciou sucesso.In vitro produced bovine embryos at morula stage were cultured in medium containing high titer of rat H-Y antisera for 24h. The embryos were classified in two groups: 1) embryos arrested at morula stage (classified as males); and 2) embryos that developed and formed a blastocoele (classified as female). The sex of 311 embryos, divided in three groups of concentration of H-Y antisera, 3%, 5% or 7%, was identified by polimerase chain reaction. The results showed no difference (P>0.05) on sexual deviation in groups in which the H-Y antisera was added, in relation to control group, in which no H-Y antisera was added. In contrast with results obtained with in vivo produced bovine embryos, the sexing of in vitro produced bovine embryos with high H-Y antisera titer did not succed.CNP

    Travelling waves for the Gross-Pitaevskii equation II

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    The purpose of this paper is to provide a rigorous mathematical proof of the existence of travelling wave solutions to the Gross-Pitaevskii equation in dimensions two and three. Our arguments, based on minimization under constraints, yield a full branch of solutions, and extend earlier results, where only a part of the branch was built. In dimension three, we also show that there are no travelling wave solutions of small energy.Comment: Final version accepted for publication in Communications in Mathematical Physics with a few minor corrections and added remark

    Cissus Sicyoides: Pharmacological Mechanisms Involved In The Anti-inflammatory And Antidiarrheal Activities

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    The objective of this study was to evaluate the pharmacological mechanisms involved in anti-inflammatory and antidiarrheal actions of hydroalcoholic extract obtained from the leaves of Cissus sicyoides (HECS). The anti-inflammatory effect was evaluated by oral administration of HECS against acute model of edema induced by xylene, and the mechanisms of action were analysed by involvement of arachidonic acid (AA) and prostaglandin E2 (PGE2). The antidiarrheal effect of HECS was observed and we analyzed the motility and accumulation of intestinal fluid. We also analyzed the antidiarrheal mechanisms of action of HECS by evaluating the role of the opioid receptor, α2 adrenergic receptor, muscarinic receptor, nitric oxide (NO) and PGE2. The oral administration of HECS inhibited the edema induced by xylene and AA and was also able to significantly decrease the levels of PGE2. The extract also exhibited significant anti-diarrheal activity by reducing motility and intestinal fluid accumulation. This extract significantly reduced intestinal transit stimulated by muscarinic agonist and intestinal secretion induced by PGE2. Our data demonstrate that the mechanism of action involved in the anti-inflammatory effect of HECS is related to PGE2. The antidiarrheal effect of this extract may be mediated by inhibition of contraction by acting on the intestinal smoothmuscle and/or intestinal transit. © 2016 by the authors; licensee MDPI, Basel, Switzerland.17

    Pre-B Cell Receptor Signaling Induces Immunoglobulin κ Locus Accessibility by Functional Redistribution of Enhancer-Mediated Chromatin Interactions

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    During B cell development, the precursor B cell receptor (pre-BCR) checkpoint is thought to increase immunoglobulin κ light chain (Igκ) locus accessibility to the V(D)J recombinase. Accordingly, pre-B cells lacking the pre-BCR signaling molecules Btk or Slp65 showed reduced germline Vκ transcription. To investigate whether pre-BCR signaling modulates Vκ accessibility through enhancer-mediated Igκ locus topology, we performed chromosome conformation capture and sequencing analyses. These revealed that already in pro-B cells the κ enhancers robustly interact with the ∼3.2 Mb Vκ region and its flanking sequences. Analyses in wild-type, Btk, and Slp65 single- and double-deficient pre-B cells demonstrated that pre-BCR signaling reduces interactions of both enhancers with Igκ locus flanking sequences and increases interactions of the 3′κ enhancer with Vκ genes. Remarkably, pre-BCR signaling does not significantly affect interactions between the intronic enhancer and Vκ genes, which are already robust in pro-B cells. Both enhancers interact most frequently with highly used Vκ genes, which are often marked by transcription factor E2a. We conclude that the κ enhancers interact with the Vκ region already in pro-B cells and that pre-BCR signaling induces accessibility through a functional redistribution of long-range chromatin interactions within the Vκ region, whereby the two enhancers play distinct roles

    Traveling waves for nonlinear Schr\"odinger equations with nonzero conditions at infinity, II

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    We prove the existence of nontrivial finite energy traveling waves for a large class of nonlinear Schr\"odinger equations with nonzero conditions at infinity (includindg the Gross-Pitaevskii and the so-called "cubic-quintic" equations) in space dimension N2 N \geq 2. We show that minimization of the energy at fixed momentum can be used whenever the associated nonlinear potential is nonnegative and it gives a set of orbitally stable traveling waves, while minimization of the action at constant kinetic energy can be used in all cases. We also explore the relationship between the families of traveling waves obtained by different methods and we prove a sharp nonexistence result for traveling waves with small energy.Comment: Final version, accepted for publication in the {\it Archive for Rational Mechanics and Analysis.} The final publication is available at Springer via http://dx.doi.org/10.1007/s00205-017-1131-

    Estimating the global conservation status of more than 15,000 Amazonian tree species

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    Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict thatmost of the world’s >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century
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