Mostrando recursos 4,701 - 4,720 de 12,572

  1. Inteligencia para la alimentación, alimentación para la inteligencia

    Oscar Prospéro-García; Mónica Méndez Díaz; Ilia Alvarado Capuleño; Marcel Pérez Morales; Jehú López Juárez; Alejandra E. Ruiz Contreras
    Comer es una conducta dirigida a conseguir la energía para llevar a cabo las funciones que mantienen al organismo y le permiten contender contra las demandas del medio. Debido a que nuestro organismo evolucionó dentro de un ambiente con escasez de alimentos, los genes que nos adaptaron al medio fueron los que promueven el almacenamiento y optimización de los nutrientes, así como aquellos que promueven la habilidad de generar estrategias de cacería y otras conductas orientadas a ese objetivo. Estos mecanismos fisiológicos y bioquímicos incluyen una amplia variedad de genes, desde aquellos que codifican para enzimas que almacenan el glucógeno...

  2. Participación de los sistemas endógenos de péptidos opioides en los mecanismos de reforzamiento y dependencia al alcohol

    Milagros Méndez
    Evidencias bioquímicas y conductuales indican que el sistema dopa- minérgico mesolímbico cumple un papel fundamental en los meca- nismos de reforzamiento y recompensa del alcohol (etanol) y otras drogas de abuso. Se ha propuesto también que la actividad de la vía dopaminérgica nigroestriatal determina la sensibilidad cerebral a etanol, lo que parece estar directamente relacionado con los procesos de adicción a la droga. Además de la dopamina, varios neurotrans- misores y neuromoduladores están implicados en los mecanismos de reforzamiento del etanol, entre ellos, el ácido gama-aminobutírico (GABA), el glutamato, la serotonina, la acetilcolina y los péptidos opioides (encefalinas, endorfinas y...

  3. Molecular and functional characterization of the HP1c complex in Drosophila melanogaster

    Kessler, Roman, 1983-
    Unlike characteristic HP1 proteins, the HP1c isoform of Drosophila melanogaster is a euchromatic protein. HP1c forms a complex with the zinc finger proteins ROW and WOC, which are crucial for HP1c function. In the present work, we aimed to further characterize the HP1c complex. We purified several novel factors that are associated with the complex. In particular, we characterize the ubiquitin receptor Dsk2 as an intrinsic subunit of the HP1c complex. Further, we show that the HP1c complex binds to TSS of actively transcribed genes and contributes positively to their transcription. The HP1c complex promotes an active chromatin state at...

  4. El perfil de los propietarios: el origen molecular del cáncer humano en la historia

    Wulff Barreiro, Enrique
    De 1977 a 1980, se introdujo con éxito la búsqueda de genes capaces de inducir la alteración del genotipo y del fenotipo en base a experiencias de transferencia de genes mediada por ADN. El paso siguiente fue la purificación del primer gen de mamífero por vía genética, en 1980. Y en 1981, tuvo lugar el primer clonaje de un oncogén humano. De hecho, cuando en 1982 se descubrió que la activación funcional de un oncogén humano estaba causada por la mutación en un único nucleótido, la importancia de la presencia de científicos españoles en este trabajo pionero adquirió perspectiva histórica....

  5. EFFECT OF HUMIC SUBSTANCES AND WEATHER CONDITIONS ON LEAF BIOCHEMICAL CHANGES OF FERTIGATED GUAVA TREE,

    During Orchard Establishment; Bárbara França Dantas; Maiane Santos Pereira; Luciana De; Sá Ribeiro; Joselanne Luiza; Trajano Maia; Luis Henrique Bassoi; Efeito De; Substâncias Húmicas; E Condições Meteorológicas; Nas Alterações; Bioquímicas Foliares; Em Goiabeiras Fertirrigada; Durante A Formação; Do Pomar
    its improvements on soil conditions and in plant nutrient uptake, metabolism and growth, reported from different growing places and crops. Nevertheless, little information about plant response to humic substance usage for local soil, weather and cropping system conditions is known. Hence, the metabolic response of guava tree during the orchard establishment to fertigation with humic substances and its correlation to the weather conditions were evaluated in Petrolina, State of Pernambuco. The treatments were manure application in soil combined with mineral fertilizers and humic substances applied through irrigation water. The results showed that the fertigation treatments and plant age did not...

  6. Electrochemical Behavior of Fe3Al Modified with Ni in Hank´s Solution

    Depto De; Ingeniería Química Bioquímica
    An investigation about the corrosion resistance of Fe3Al-type intermetallic alloys in Hank´s solution was carried out via electrochemical techniques. The Fe3Al intermetallic alloy was modified with additions of Ni and evaluated in the as cast and thermal treated conditions. For comparison, Titanium and 316-L stainless steel were also evaluated. For evaluation purposes, electrochemical techniques included potentiodynamic polarization curves, open circuit potential measurements, linear polarization resistance curves and cyclic polarization curves were employed. Results shown that the 316-L stainless steel and titanium are the materials with greater corrosion resistance in chloride-rich environments showing an active-passive behavior and are susceptible to pitting...

  7. Instituto de Genetica e Bioquimica, Universidade Federal de Uberlandia, P.O.Box 38400-902

    Electrochemical Biosensors; Rodrigo M. Iost; João M. Madurro; Ana G. Brito-madurro; Iseli L. Nantes; Frank N. Crespilho; Minas Gerais
    3

  8. Avaliação da toxicidade aguda pré-clínica do extrato metanólico das cascas do caule de Parahancornia amapa (Apocynaceae)

    SILVA,Simoni Lobato da; NASCIMENTO,Alessandra Azevedo do; RIBEIRO,Edson Fábio Brito; RIBEIRO,Renata Barbosa; ALVES,Cleiziane Melo; SANTOS,André Mendonça dos; BURMANN,Aurélio Pinheiro Rodrigues; MIRA NETO,Raimundo de Almeida
    RESUMOParahancornia amapa é uma espécie endêmica do Estado do Amapá, na região Amazônica. Este estudo teve como objetivo avaliar a toxicidade aguda do extrato metanólico das cascas do caule de P. amapa. Diferentes concentrações do extrato foram adicionadas aos camarões de salmoura (Artemia salina) e a concentração letal média (CL50) foi avaliada. Os resultados desse ensaio indicaram que o extrato não era tóxico. A toxicidade aguda foi estudada em ratos Wistar (machos e fêmeas) após dose única (2000 mg kg-1) por gavagem. Ingestão de água e comida, peso corporal, alterações comportamentais e mortalidade foram anotados. Amostras de sangue foram coletadas...

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    Clara M. S. Camargo; José M. B. Duarte; José J. Fagliari; André M. Santana; Kalina M. M. G. Simplício; Aureo E. Santana
    RESUMO.- [Efeito do sexo e estações do ano sobre as variáveis hematológicas e bioquímico-séricas de ve-ados-catingueiro (Mazama gouazoubira) criados em cativeiro.] O veado-catingueiro (Mazama gouazoubira) é o cervídeo de vida livre mais comum na América do Sul, es-pecialmente no Brasil, e tem grande importância ecológica e científica. No entanto, dados sobre parâmetros hemato-lógicos e bioquímicos nesta espécie animal são escassos. O Effect of sex and seasons of the year on hematologic and serum biochemical variables of captive brown brocket deer (Mazama gouazoubira)1

  10. Estudio mediante técnicas no invasivas del efecto de la programación fetal sobre el crecimiento postnatal en el cerdo ibérico

    Barbero Fernández, Alicia
    La investigación en ganado porcino se caracteriza por su doble utilidad en Producción Animal y como modelo para Medicina Humana. El cerdo es uno de los modelos de obesidad más empleados en nvestigación biomédica. Entre las diferentes razas porcinas, el cerdo Ibérico se caracteriza por presentar un polimorfismo en el gen que codifica el receptor de la leptina, que constituye un síndrome de resistencia a la leptina¿ similar al encontrado en humanos y que condiciona su elevada tendencia al engrasamiento y desarrollo de obesidad. Estudios recientes realizados en otras especies animales confirman que los síndromes de obesidad y alteraciones metabólicas...

  11. Estudio de la expresión génica durante la diferenciaciónde células de neuroblastoma SH-SY5Y inducida con Acido Retinoico

    Meseguer, Salvador; Ruíz, Nuria; Barettino, Domingo
    Póster original, presentado al XXXI Congreso de la Sociedad Española de Bioquímica y Biología Molecular. Bilbao, del 10 al 13 de Septiembre de 2008.

  12. FLRT3: mecanismes moleculars de senyalització en el desenvolupament dels axons talamocorticals

    Menal Castellote, Maria José
    En aquest estudi hem trobat que FLRT3 (Fibronectin Leucine-Rich Transmembrane protein) interacciona amb el receptor de Slit, Robo1, de forma independent lligand. En cèl•lules HEK293T hem vist que FLRT3 i Robo1 interaccionen mitjançant els seus dominis intracel•lulars, que la co-expressió de FLRT3 amb Robo1 indueix el processament del receptor i que FLRT3 interacciona amb el fragment intracel•lular generat amb major afinitat i el segresta a la membrana. En presència de Slit, es produeix un increment en el processament de Robo1 i el fragment intracel•lular generat és captat per FLRT3. La interacció entre FLRT3-Robo1 i entre FLRT3-Robo1ICD es dóna en neurones talàmiques...

  13. Mecanismos moleculares y funcionales asociados a la activación de los Receptores X del hígado (LXR) en modelos de enfermedad de Alzheimer

    Sandoval Hernández, Adrián Gabriel
    La enfermedad de Alzheimer (EA) es una patología de etiología desconocida y la demencia más común. La activación farmacológica de los receptores X del hígado (LXR) produce mejoría cognitiva asociada al incremento de los niveles de ApoE. Objetivo: Describir mecanismo de acción implicados en la mejoría cognitiva de la activación farmacológica de LXR. Métodos: Se realizaron tratamientos farmacológicos con un agonista de LXR (GW3965) en animales triple transgénicos de Enfermedad de Alzheimer (3xTg-AD) y se evaluaron cambios cognitivos, histopatológicos, bioquímicos, epigenéticos. Adicionalmente, se estudió el mecanismo de acción de LXR in-vitro en cultivos de líneas celulares, cultivos primarios de neuronas...

  14. Production and Characterization of the Ectodomain of E2 Envelope Glycoprotein of Hepatitis C Virus Folded in the Presence of Full-length E1 glycoprotein

    Ortega-Atienza, Sara; Lombana, Laura; Gómez-Gutiérrez, Julián; Yélamos, Belén; Peterson, Darrell L.; Gavilanes, Francisco
    Hepatitis C virus (HCV) envelope glycoproteins, E1 and E2, are involved in the first steps of virus infection. The E2 ectodomain can be produced as an isolated form (E2661). However, there is some concern about its proper conformation and the role that E1 can play as a chaperone for the folding of E2. In order to verify this fact we have expressed a chimeric protein (E1tmbE2) based on the full-length E1 sequence followed by the E2 ectodomain using the baculovirus-insect cells system. The E2 ectodomain is folded in the presence of the E1, proteolytically processed by cellular proteases and secreted...

  15. Expression and structural properties of a chimeric protein based on the ectodomains of E1 and E2 hepatitis C virus envelope glycoproteins

    Tello, Daniel; Rodríguez-Rodríguez, Mar; Yélamos, Belén; Gómez-Gutiérrez, Julián; Ortega, Sara; Pacheco, Beatriz; Peterson, Darrell L.; Gavilanes, Francisco
    Hepatitis C virus encodes two enveloped glycoproteins, E1 and E2, which are involved in viral attachment and entry into target cells. We have obtained in insect cells infected by recombinant baculovirus a chimeric secreted recombinant protein, E1341E2661, containing the ectodomains of E1 and E2. The described procedure allows the purification of approximately 2 mg of protein from 1 L of culture media. Sedimentation velocity experiments and SDS-PAGE in the absence of reducing agents indicate that the protein has a high tendency to self-associate, the dimer being the main species observed. All the oligomeric forms observed maintain a conformation which is...

  16. High-yield production of a chimeric glycoprotein based on permuted E1 and E2 HCV envelope ectodomains

    Tello, Daniel; Rodríguez-Rodríguez, Mar; Yélamos, Belén; Gómez-Gutiérrez, Julián; Peterson, Darrell L.; Gavilanes, Francisco
    In this report it is described for the first time the expression and purification of large quantities of a oluble and correctly folded chimeric recombinant protein, E2661E1340, containing the permuted Hepatitis C virus (HCV) glycoprotein ectodomains E1 (amino acids 192-340) and E2 (amino acids 384-661). Using the baculovirus/insect cell expression system, 8mg of secreted protein were purified from 1L of culture media, a yield 4 times higher than the described for its counterpart E1341E2661. This permuted chimeric protein is glycosylated and possesses a high tendency to self-associate. The fluorescence emission spectrum indicates that Trp residues occupy a relatively low hydrophobic...

  17. Fusogenic properties of the ectodomains of hepatitis C virus envelope proteins

    Tello, Daniel; Rodríguez-Rodríguez, Mar; Ortega, Sara; Lombana, Laura; Yélamos, Belén; Gómez-Gutiérrez, Julián; Peterson, Darrell L.; Gavilanes, Francisco
    We have used an isolated chimeric protein E1340E2661 that includes the ectodomains of the envelope proteins of epatitis C virus to study its interaction with model membranes. E1340E2661 has some of the membrane destabilization properties, vesicle aggregation, lipid mixing and the release of internal aqueous content, which have previously been ascribed to fusion proteins. The effects are preferentially produced on vesicles of acidic phospholipids which would indicate the importance of the electrostatic interactions. In fact, an increase of the ionic strength of the buffer induced a considerable decrease of the destabilizing properties. Moreover, fluorescence polarization studies show that the recombinant...

  18. Study of the Putative Fusion Regions of the preS Domain of Hepatitis B Virus

    Delgado, Carmen L.; Núñez, Elena; Yélamos, Belén; Gómez-Gutiérrez, Julián; Peterson, Darrell L.; Gavilanes, Francisco
    In a previous study, it was shown that purified preS domains of hepatitis B virus (HBV) could interact with acidic phospholipid vesicles and induce aggregation, lipid mixing and leakage of internal contents which could be indicative of their involvement in the fusion of the viral and cellular membranes (Núñez, E. et al. 2009. Interaction of preS domains of hepatitis B virus with phospholipid vesicles. Biochim. Biophys. Acta 17884:417-424). In order to locate the region responsible for the fusogenic properties of preS, five mutant proteins have been obtained from the preS1 domain of HBV, in which 40 amino acids have been...

  19. Interaction of preS domains of Hepatitis B Virus with phospholipid vesicles

    Núñez, Elena; Yélamos, Belén; Delgado, Carmen; Gómez-Gutiérrez, Julián; Peterson, Darrell L.; Gavilanes, Francisco
    The role of preS domains of the hepatitis B virus (HBV) envelope proteins in the first steps of viral infection has been restricted to their implication in virus attachment to a putative hepatocyte receptor. In order to explore a fusion activity in these regions, we used recombinant preS domains to characterize their interaction with liposomes. Binding experiments carried out with NBD-labeled proteins indicated that preS were able to interact in a monomeric way with acidic phospholipid vesicles, being the partition coefficient similar to that described for peptides which can insert deeply into bilayers. Fluorescence depolarization of DPH-labeled vesicles confirmed the...

  20. Membrane-perturbing properties of three peptides corresponding to the ectodomain of hepatitis C virus E2 envelope protein

    Pacheco, Beatriz; Gómez-Gutiérrez, Julián; Yélamos, Belén; Delgado, Carmen; Roncal, Fernando; Albar, Juan P.; Peterson, Darrell; Gavilanes, Francisco
    Based on the predicted capacity to interact with membranes at the interface, we have found three regions in the ectodomain of the hepatitis C virus envelope glycoprotein E2 (430-449, 543-560 and 603-624) with the ability to destabilize membranes. Three peptides corresponding to the sequence of these regions have been synthesized and their interaction with liposomes have been characterized. The three peptides were able to insert deeply into the hydrophobic core of negatively charged phospholipids as stated by fluorescence depolarization of the probe 1,6-diphenyl-1,3,5- hexatriene. Peptides E2430-449 and E2603-624 were able to induce aggregation of phosphatidylglycerol vesicles in a concentration-dependent manner...

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