764 research outputs found

    Functional Diversification after Gene Duplication: Paralog Specific Regions of Structural Disorder and Phosphorylation in p53, p63, and p73

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    Conformational and functional flexibility promote protein evolvability. High evolvability allows related proteins to functionally diverge and perhaps to neostructuralize. p53 is a multifunctional protein frequently referred to as the Guardian of the Genome–a hub for e.g. incoming and outgoing signals in apoptosis and DNA repair. p53 has been found to be structurally disordered, an extreme form of conformational flexibility. Here, p53, and its paralogs p63 and p73, were studied for further insights into the evolutionary dynamics of structural disorder, secondary structure, and phosphorylation. This study is focused on the post gene duplication phase for the p53 family in vertebrates, but also visits the origin of the protein family and the early domain loss and gain events. Functional divergence, measured by rapid evolutionary dynamics of protein domains, structural properties, and phosphorylation propensity, is inferred across vertebrate p53 proteins, in p63 and p73 from fish, and between the three paralogs. In particular, structurally disordered regions are redistributed among paralogs, but within clades redistribution of structural disorder also appears to be an ongoing process. Despite its deemed importance as the Guardian of the Genome, p53 is indeed a protein with high evolvability as seen not only in rearranged structural disorder, but also in fluctuating domain sequence signatures among lineages

    Protein evolution along phylogenetic histories under structurally constrained substitution models

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    Motivation: Models of molecular evolution aim at describing the evolutionary processes at the molecular level. However, current models rarely incorporate information from protein structure. Conversely, structure-based models of protein evolution have not been commonly applied to simulate sequence evolution in a phylogenetic framework, and they often ignore relevant evolutionary processes such as recombination. A simulation evolutionary framework that integrates substitution models that account for protein structure stability should be able to generate more realistic in silico evolved proteins for a variety of purposes. Results: We developed a method to simulate protein evolution that combines models of protein folding stability, such that the fitness depends on the stability of the native state both with respect to unfolding and misfolding, with phylogenetic histories that can be either specified by the user or simulated with the coalescent under complex evolutionary scenarios, including recombination, demographics and migration. We have implemented this framework in a computer program called ProteinEvolver. Remarkably, comparing these models with empirical amino acid replacement models, we found that the former produce amino acid distributions closer to distributions observed in real protein families, and proteins that are predicted to be more stable. Therefore, we conclude that evolutionary models that consider protein stability and realistic evolutionary histories constitute a better approximation of the real evolutionary process.Ministerio de Ciencia e Innovación | Ref. BFU2011-24595Ministerio de Economía y Competitividad | Ref. BFU2012-40020Ministerio de Ciencia e Innovación | Ref. JCI-2011-1045

    Paralog-Specific Patterns of Structural Disorder and Phosphorylation in the Vertebrate SH3–SH2–Tyrosine Kinase Protein Family

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    One of the largest multigene families in Metazoa are the tyrosine kinases (TKs). These are important multifunctional proteins that have evolved as dynamic switches that perform tyrosine phosphorylation and other noncatalytic activities regulated by various allosteric mechanisms. TKs interact with each other and with other molecules, ultimately activating and inhibiting different signaling pathways. TKs are implicated in cancer and almost 30 FDA-approved TK inhibitors are available. However, specific binding is a challenge when targeting an active site that has been conserved in multiple protein paralogs for millions of years. A cassette domain (CD) containing SH3–SH2–Tyrosine Kinase domains reoccurs in vertebrate nonreceptor TKs. Although part of the CD function is shared between TKs, it also presents TK specific features. Here, the evolutionary dynamics of sequence, structure, and phosphorylation across the CD in 17 TK paralogs have been investigated in a large-scale study. We establish that TKs often have ortholog-specific structural disorder and phosphorylation patterns, while secondary structure elements, as expected, are highly conserved. Further, domain-specific differences are at play. Notably, we found the catalytic domain to fluctuate more in certain secondary structure elements than the regulatory domains. By elucidating how different properties evolve after gene duplications and which properties are specifically conserved within orthologs, the mechanistic understanding of protein evolution is enriched and regions supposedly critical for functional divergence across paralogs are highlighted

    Serpa PDO cheese: towards identification of chemical markers involved in organoleptic attributes

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    Serpa is a PDO cheese manufactured using raw ovine milk and extracts of C. cardunculus L. as rennet, without addition of starter cultures and followed by a minimum (but safe) ripening period. Both the processing technology and ingredients used result in a high microbial biodiversity that allows the development of a unique flavor. Variations in the manufacture process and distinct milk composition among producers result in a considerably heterogeneous cheese. The present study aimed at screening some groups of sensorial related compounds during two consecutive months of production, towards the identification of chemical markers involved in the specificity of Serpa cheese. The results suggested a high diversity and heterogenous chemical composition according to the producer and month. The free amino acids (FAAs) profile suggested the presence of almost all amino acids in the analyzed cheeses, being glutamic acid, alanine, leucine, valine and phenylalanine the most prevalent ones. Regarding the organic acid profile, lactic and acetic acids were the dominant groups. The volatile analysis suggested a high diversity and variability of volatile composition between cheeses, including several chemical groups, namely, ethyl esters, aldehydes and alcohols. The identification of sensorial chemical markers will be crucial to guide the selection and development of an autochthonous starter culture to improve Serpa’s quality and safety..info:eu-repo/semantics/publishedVersio

    Guillain-Barré syndrome in temporal association with influenza A vaccine

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    OBJECTIVE: To report a case of Guillain-Barré syndrome following influenza A (H1N1) 2009 vaccine. CASE DESCRIPTION: A four-year-old boy presented right thigh pain and ascending muscular weakness 15 days after the second dose of influenza A (H1N1) 2009 vaccine. The neurological examination revealed tetraparesis and areflexia. Electroneuromyography showed lower velocity and conduction blockage with small secondary axonal loss. Treated with intravenous immunoglobulin, the patient reached a plateau in the 4th day, followed by progressive muscular strength improvement. COMMENTS: The employment of large-scale influenza A (H1N1) 2009 vaccination and the preliminary reports from the American Surveillance Program suggest a significant association between Guillain-Barré syndrome and influenza A H1N1 2009 vaccination. All suspected cases of this association should be published for further evaluation. Vaccination remains the most effective method to prevent serious illness and death related to influenza.OBJETIVO: Descrever um caso de síndrome de Guillain-Barré em associação temporal com a vacina influenza A (H1N1) 2009. DESCRIÇAO DO CASO: Menino de quatro anos com queixa inicial de dor em coxa direita e perda de força muscular ascendente 15 dias após a segunda dose da vacina influenza A (H1N1) 2009. Ao exame neurológico apresentava tetraparesia e arreflexia, com predomínio em membros inferiores. A eletroneuromiografia evidenciou redução da velocidade e bloqueio de condução neuronal, com discreta perda axonal secundária. Foi tratado com imunoglobulina por via intravenosa, atingiu platô no quarto dia de evolução da doença e, depois, houve melhora progressiva da força muscular. COMENTÁRIOS: Com o emprego em larga escala da vacina influenza A (H1N1) 2009 em nosso meio e os dados preliminares do sistema de vigilância norte-americano mostrando associação temporal significante com a síndrome de Guillain-Barré, recomenda-se a descrição dos casos suspeitos dessa associação. A vacina continua sendo o método mais efetivo para prevenir doença grave e morte por influenza.Universidade Federal de São Paulo (UNIFESP)UNIFESPSciEL

    Metformin, but not glimepiride, improves carotid artery diameter and blood flow in patients with type 2 diabetes mellitus

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    OBJECTIVE: To compare the effects of glimepiride and metformin on vascular reactivity, hemostatic factors and glucose and lipid profiles in patients with type 2 diabetes. METHODS: A prospective study was performed in 16 uncontrolled patients with diabetes previously treated with dietary intervention. The participants were randomized into metformin or glimepiride therapy groups. After four months, the patients were crossed over with no washout period to the alternative treatment for an additional four-month period on similar dosage schedules. The following variables were assessed before and after four months of each treatment: 1) fasting glycemia, insulin, catecholamines, lipid profiles and HbA1 levels; 2) t-PA and PAI-1 (antigen and activity), platelet aggregation and fibrinogen and plasminogen levels; and 3) the flow indices of the carotid and brachial arteries. In addition, at the end of each period, a 12-hour metabolic profile was obtained after fasting and every 2 hours thereafter. RESULTS: Both therapies resulted in similar decreases in fasting glucose, triglyceride and norepinephrine levels, and they increased the fibrinolytic factor plasminogen but decreased t-PA activity. Metformin caused lower insulin and pro-insulin levels and higher glucagon levels and increased systolic carotid diameter and blood flow. Neither metformin nor glimepiride affected endothelial-dependent or endothelial-independent vasodilation of the brachial artery. CONCLUSIONS: Glimepiride and metformin were effective in improving glucose and lipid profiles and norepinephrine levels. Metformin afforded more protection against macrovascular diabetes complications, increased systolic carotid artery diameter and total and systolic blood flow, and decreased insulin levels. As both therapies increased plasminogen levels but reduced t-PA activity, a coagulation process was likely still ongoing

    Erythropoietin reduces the expression of myostatin in mdx dystrophic mice

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    Erythropoietin (EPO) has been well characterized as a renal glycoprotein hormone regulating red blood cell production by inhibiting apoptosis of erythrocyte progenitors in hematopoietic tissues. EPO exerts regulatory effects in cardiac and skeletal muscles. Duchenne muscular dystrophy is a lethal degenerative disorder of skeletal and cardiac muscle. in this study, we tested the possible therapeutic beneficial effect of recombinant EPO (rhEPO) in dystrophic muscles in mdx mice. Total strength was measured using a force transducer coupled to a computer. Gene expression for myostatin, transforming growth factor-beta 1 (TGF-beta 1), and tumor necrosis factor-alpha (TNF-alpha) was determined by quantitative real time polymerase chain reaction. Myostatin expression was significantly decreased in quadriceps from mdx mice treated with rhEPO (rhEPO = 0.60 +/- 0.11, control= 1.07 +/- 0.11). On the other hand, rhEPO had no significant effect on the expression of TGF-beta 1 (rhEPO = 0.95 +/- 0.14, control= 1.05 +/- 0.16) and TNF-alpha (rhEPO = 0.73 +/- 0.20, control= 1.01 +/- 0.09). These results may help to clarify some of the direct actions of EPO on skeletal muscle.Fac Med ABC, BR-09060650 Santo Andre, SP, BrazilUniv São Paulo, Inst Ciencias Biomed, BR-05508 São Paulo, BrazilUniversidade Federal de São Paulo, Inst Ciencias Quim Ambientais & Farmaceut, Diadema, SP, BrazilUniversidade Federal de São Paulo, Inst Ciencias Quim Ambientais & Farmaceut, Diadema, SP, BrazilWeb of Scienc

    EVOLUÇÃO DAS POLÍTICAS RELACIONADAS À SAÚDE DA CRIANÇA NO ÂMBITO DA ATENÇÃO PRIMÁRIA BRASILEIRA

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    Introdução: As políticas públicas são essenciais para reduzir a morbimortalidade infantil. Este estudo descreve a evolução das políticas relacionadas à atenção à criança no âmbito da Atenção Primária à Saúde (APS) no Brasil, implementadas desde a criação do Sistema Único de Saúde (SUS). Metodologia: Revisão narrativa da literatura com base nos principais marcos regulatórios com influência direta ou indireta na Atenção à Saúde da Criança (ACS) na APS, publicados entre 1990 e 2017. Resultados: Foram analisados ​​31 documentos oficiais, organizados em uma linha do tempo e classificados em três categorias: I) Normas do SUS e da APS; II) diretrizes para os serviços de saúde materno-infantil no âmbito da APS; e, III) políticas intersetoriais. Conclusão:A evolução das políticas de CSC no Brasil é marcada por uma série de conquistas em prol da ampliação dos direitos sociais e da garantia do direito à saúde que ampliou o acesso aos serviços de saúde e contribuiu para a melhoria das condições de vida e de vida das crianças. No entanto, as desigualdades sociais e os desafios no acesso e qualidade da atenção na APS são persistentes, com retrocessos causados ​​pela implementação de medidas de austeridade desde 2016.Introdução: Políticas públicas são fundamentais para a redução da morbimortalidade na infância. O presente estudo descreve uma evolução política relacionada à Atenção Primária à Saúde da Criança no âmbito da Atenção Primária Saúde (APS) no Brasil, desde a criação do Sistema Único de Saúde (SUS). Metodologia: Revisão narrativa da literatura com base nos principais marcos normativos com influência na Atenção à Saúde da Criança no âmbito da APS, publicados entre 1990 e 2017. Resultados: Foram analisados 31 documentos oficiais, distribuídos numa linha do tempo, classificados em: I) normatização do SUS e da APS; II) orientação aos serviços de saúde materno-infantil no âmbito da APS e III) políticas intersetoriais. Conclusão: A evolução das políticas pensadas no Brasil está marcada para serviços e como soluções da série de direitos sociais e como possibilidades de vistas da vida. Porém, além das desigualdades sociais, desafios no acesso e na qualidade do cuidado na APS se fazem persistentes, com retrocessos são persistentes agravados com a capacidade de trabalhar1 em medidas de austeridade curso desde 206
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