991 resultados para Oxidase alternativa
Resumo:
Basophils are primarily associated with a proinflammatory and immunoregulatory role in allergic diseases and parasitic infections. Recent studies have shown that basophils can also bind various bacteria both in the presence and the absence of opsonizing Abs. In this report, we show that both human and mouse basophils are able to produce mitochondrial reactive oxygen species and to form extracellular DNA traps upon IL-3 priming and subsequent activation of the complement factor 5 a receptor or FcεRI. Such basophil extracellular traps (BETs) contain mitochondrial, but not nuclear DNA, as well as the granule proteins basogranulin and mouse mast cell protease 8. BET formation occurs despite the absence of any functional NADPH oxidase in basophils. BETs can be found in both human and mouse inflamed tissues, suggesting that they also play a role under in vivo inflammatory conditions. Taken together, these findings suggest that basophils exert direct innate immune effector functions in the extracellular space.
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The ba3-type cytochrome c oxidase from Thermus thermophilus is a membrane-bound protein complex that couples electron transfer to O2 to proton translocation across the membrane. To elucidate the mechanism of the redox-driven proton pumping, we investigated the kinetics of electron and proton transfer in a structural variant of the ba3 oxidase where a putative "pump site" was modified by replacement of Asp372 by Ile. In this structural variant, proton pumping was uncoupled from internal electron transfer and O2 reduction. The results from our studies show that proton uptake to the pump site (time constant ∼65 μs in the wild-type cytochrome c oxidase) was impaired in the Asp372Ile variant. Furthermore, a reaction step that in the wild-type cytochrome c oxidase is linked to simultaneous proton uptake and release with a time constant of ∼1.2 ms was slowed to ∼8.4 ms, and in Asp372Ile was only associated with proton uptake to the catalytic site. These data identify reaction steps that are associated with protonation and deprotonation of the pump site, and point to the area around Asp372 as the location of this site in the ba3 cytochrome c oxidase.
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The bioelectrocatalytic (oxygen reduction reaction, ORR) properties of the multicopper oxidase CueO immobilized on gold electrodes were investigated. Macroscopic electrochemical techniques were combined with in situ scanning tunneling microscopy (STM) and surface-enhanced Raman spectroscopy at the ensemble and at the single-molecule level. Self-assembled monolayer of mercaptopropionic acid, cysteamine, and p-aminothiophenol were chosen as redox mediators. The highest ORR activity was observed for the protein attached to amino-terminated adlayers. In situ STM experiments revealed that the presence of oxygen causes distinct structure and electronic changes in the metallic centers of the enzyme, which determine the rate of intramolecular electron transfer and, consequently, affect the rate of electron tunneling through the protein. Complementary Raman spectroscopy experiments provided access for monitoring structural changes in the redox state of the type 1 copper center of the immobilized enzyme during the CueO-catalyzed oxygen reduction cycle. These results unequivocally demonstrate the existence of a direct electronic communication between the electrode substrate and the type 1 copper center.
Resumo:
Correction of human myeloid cell function is crucial for the prevention of inflammatory and allergic reactions as well as leukaemia progression. Caffeine, a naturally occurring food component, is known to display anti-inflammatory effects which have previously been ascribed largely to its inhibitory actions on phosphodiesterase. However, more recent studies suggest an additional role in affecting the activity of the mammalian target of rapamycin (mTOR), a master regulator of myeloid cell translational pathways, although detailed molecular events underlying its mode of action have not been elucidated. Here, we report the cellular uptake of caffeine, without metabolisation, by healthy and malignant hematopoietic myeloid cells including monocytes, basophils and primary acute myeloid leukaemia mononuclear blasts. Unmodified caffeine downregulated mTOR signalling, which affected glycolysis and the release of pro-inflammatory/pro-angiogenic cytokines as well as other inflammatory mediators. In monocytes, the effects of caffeine were potentiated by its ability to inhibit xanthine oxidase, an enzyme which plays a central role in human purine catabolism by generating uric acid. In basophils, caffeine also increased intracellular cyclic adenosine monophosphate (cAMP) levels which further enhanced its inhibitory action on mTOR. These results demonstrate an important mode of pharmacological action of caffeine with potentially wide-ranging therapeutic impact for treating non-infectious disorders of the human immune system, where it could be applied directly to inflammatory cells.
Resumo:
Non-pregnant, female adult rats pretreated with either phenobarbital (PB) or (beta)-naphthoflavone ((beta)NF) through short-course intraperitoneal injections were shown by sodium dithionite-reduced carbon monoxide difference spectroscopy and NADPH-cytochrome c in vitro assay to contain cytochrome P-450 and NADPH-dependent reductase associated with the microsomal fraction of colon mucosa. These two protein components of the mixed function oxidase system were released from the microsomal membrane, resolved from each other, and partially purified by using a combination of techniques including solubilization in nonionic detergent followed by ultracentrifugation, anion exchange and adsorption column chromatographies, native gel electrophoresis, polyethylene glycol fractionation and ultrafiltration.^ In vitro reconstitution assays demonstrated the cytochrome P-450 fraction as the site of substrate and molecular oxygen binding. By the use of immunochemical techniques including radial immunodiffusion, Ouchterlony double diffusion and protein electroblotting, the cytochrome P-450 fraction was shown to contain at least 5 forms of the protein, having molecular weights as determined by SDS gel electrophoresis identical to the corresponding hepatic cytochrome P-450. Estimation of total cytochrome P-450 content confirmed the preferential induction of particular forms in response to the appropriate drug pretreatment.^ The colonic NADPH-dependent reductase was isolated from native gel electrophoresis and second dimensional SDS gel electrophoresis was performed in parallel to that for purified reductase from liver. Comparative electrophoretic mobilities together with immunochemical analysis, as with the cytochrome P-450s, reconstitution assays, and kinetic characterization using artificial electron acceptors, gave conclusive proof of the structural and functional homology between the colon and liver sources of the enzyme.^ Drug metabolism was performed in the reconstituted mixed function oxidase system containing a particular purified liver cytochrome P-450 form or partially pure colon cytochrome P-450 fraction plus colon or liver reductase and synthetic lipid vesicles. The two drugs, benzo{(alpha)}pyrene and benzphetamine, which are most representative of the action of system in liver, lung and kidney, were tested to determine the specificity of the reconstituted system. The kinetics of benzo{(alpha)}pyrene hydroxylation were followed fluorimetrically for 3-hydroxybenzo{(alpha)}pyrene production. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI ^
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Caenorhabditis elegans has recently been developed as a model system to study both pathogen virulence mechanisms and host defense responses. We have shown that C. elegans produces reactive oxygen species (ROS) in response to exposure to the important Gram-positive, noscomial pathogen, Enterococcus faecalis. We have also shown evidence of oxidative stress and upregulation of stress response after exposure to the pathogen. As in mammalian systems, this work shows that production of ROS for innate immune functions occurs via an NADPH oxidase. Specifically, reducing expression of a dual oxidase, Ce-duox1/BLI-3 causes a decrease in ROS production in response to E. faecalis. We also present evidence that reduction of expression of Ce-duox1/BLI-3 increases susceptibility to this pathogen, specifically when expression is reduced in the intestine and the hypodermis. This dual oxidase has previously been localized to the hypodermis, but we show that it is additionally localized to the intestine of C. elegans. To further demonstrate the protective effects of the pathogen-induced ROS production, we demonstrate that antioxidants that scavenge ROS, increase the sensitivity of the nematode to the infection, in stark contrast to their longevity-promoting effects under non-pathogenic conditions. In conclusion, we postulate that the generation of ROS by NADPH oxidases in the barrier epithelium is an ancient, highly conserved innate immune defense mechanism.^
Resumo:
Arsenic trioxide (ATO) is an inorganic arsenic derivative that is very effective against relapsed acute promyelocytic leukemia. It is being investigated as therapy for other cancers, but the risk/benefit ratio is questionable due to significant side effects. In contrast, organic arsenic derivatives (OAD) are known to be much less toxic than ATO. Based on high activity, we selected GMZ27 (dipropil-s-glycerol arsenic) for further study and have confirmed its potent activity against human acute leukemia cell lines. This anti-leukemic activity is significantly higher than that of ATO. Both in vivo and in vitro tests have shown that GMZ27 is significantly less toxic to normal bone marrow mononuclear cells and normal mice. Therefore, further study of the biological activity of GMZ27 was undertaken. ^ GMZ27, in contrast to ATO, can only marginally induce maturation of leukemic cells. GMZ27 has no effect on cell cycle. The anti-leukemic activity of GMZ27 against acute myeolocytic leukemia cells is not dependent upon degradation of PML-RARα fusion protein. GMZ27 causes dissipation of mitochondrial transmembrane potential, cleavage of caspase 9, caspase 3 activation. Further studies indicated that GMZ27 induces intracellular reactive oxygen species (ROS) production, and modification of intracellular ROS levels had profound effect on its potential to inhibit proliferation of leukemic cells. Therefore ROS production plays a major role in the anti-leukemic activity of GMZ27. ^ To identify how GMZ27 induces ROS, our studies focused on mitochondria and NADPH oxidase. The results indicated that the source of ROS generation induced by GMZ27 is dose dependent. At the low dose (0.3 uM) GMZ27 induces NADPH oxidase activity that leads to late ROS production, while at the high dose (2.0 uM) mitochondria function is disrupted and early ROS production is induced leading to dramatic cell apoptosis. Therefore, late, ROS production can be detected in mitochondria are depleted Rho-0 cells. Our work not only delineates a major biologic pathway for the anti-leukemic activity of GMZ27, but also discusses possible ways of enhancing the effect by the co-application of NADPH oxidase activator. Further study of this interaction may lead to achieving better therapeutic index.^
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Pregnant Sprague-Dawley rats were gavaged with vehicle (olive oil) or 37.5, 75, 150 or 300 mg/kg of (DELTA)('9)-Tetrahydrocannabinol (THC) on days 18 or 19 of gestation. Male offspring as well as a group of hypophysectomized rats (positive control) were sacrificed at 35 days of age, while females and hypophysectomized control were sacrificed at 36 days of age. The sex-differences in ethylmorphine-N-demethylase and aniline hydroxylase liver activities were evaluated.^ Ethylmorphine-N-demethylase activity showed a significant difference between males and females from control and 37.5, 75 and 150 mg/kg THC dosed groups. Female offspring exposed prenatally to 300 mg/kg THC had a significant increase (p < .01) in N-demethylation activity, while their male counterparts had similar enzyme activity to those found in the male groups from control and 37.5 to 150 mg/kg THC dosed. Moreover, the percent increase in the 300 mg/kg THC dosed females was similar to that detected in the hypophysectomized female rats (positive control). As expected no sex difference in aniline hydroxylase activity was detected in control as well as exposed groups, including the 300 mg/kg THC dosed group.^ It is concluded that (DELTA)('9)-Tetrahydrocannabinol administered once by gavage in days 18 or 19 of gestation alters the liver Mixed Function Oxidase (MFO) sexual dimorphism imprinting process of the rat. ^
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Las políticas sociales actuales cuentan con la participación activa de la población antes considerada objeto u objetivo de los planes y programas. Configurando un nuevo modelo que busca apartarse de las viejas prácticas asistencialistas y dar lugar a las denominadas políticas de inclusión social, que aparecen como alternativas ante la falta de empleo, la precarización laboral y las dificultades de inserción en el mercado de trabajo formal. Uno de los programas que tuvo surgimiento luego de la crisis generalizada de 2001 fue el programa de microcréditos, Banco Popular de la Buena Fe. El cual tiene sus cimientos en la Economía Social y Solidaria y el protagonismo creciente de las organizaciones de la sociedad civil. El Banco Popular de la Buena Fe es uno de los programas con mayor alcance a nivel nacional, y este artículo lleva a la reflexión de si se trata de una mera política social o si estamos ante la presencia de una incipiente política de empleo.
Resumo:
Este trabajo intenta definir un modelo de desarrollo turístico en el espacio rural que permita la reactivación socioeconómica del área de estudio (Departamentos Guaraní y San Pedro de la provincia de Misiones) y que se constituya en un marco de referencia para el desarrollo de otras áreas similares de la provincia. Para ello se propone una planificación - participativa, que partiendo de previsiones de demanda y oferta culmina en el diseño de líneas de acción.
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Presentamos una experiencia y comentarios sobre neuromodulación y vejiga neurogénica. Evaluamos 32 pacientes con estimulación percutánea previa (PNE), positiva en 20 casos y negativa en 12. Los diagnósticos en las PNE negativas fueron: 7 vejigas hiperrrefléxicas, 3 vejigas neurógenas atónicas no obstructivas, 1 síndrome cortical con vejiga neurógena no inhibida y un síndrome doloroso vesical. Los mejores resultados son en vejigas hiperrrefléxicas con mejoría del 60-70%, con un seguimiento de hasta 4 años.
Resumo:
El presente trabajo ha sido realizado en el marco de la asignatura Proyecto de Tesis de la carrera Ingeniería en Recursos Naturales Renovables de la Facultad de Ciencias Agrarias (FCA), perteneciente a la Universidad Nacional de Cuyo (UNCuyo). El mismo se focaliza en el análisis y sistematización de los datos obtenidos, a partir del estudio de caso de la escuela de Permacultura “El Jardín de los Presentes" ubicada en el barrio La Toma, perteneciente al municipio de Capilla Del Monte, provincia de Córdoba, la cual se estructura en torno a los principios y de esta cosmovisión general como modo de vida. Frente al actual modelo dominante de degradación ambiental y el escenario de crisis energética que atraviesa la humanidad, provocada por el uso irracional de recursos naturales, la degradación de ecosistemas naturales, la desvinculación creciente de las personas con la naturaleza y la estructura individualista que engloba a las sociedades actuales; desde esta investigación se busca contribuir al conocimiento y la difusión de los principios de la Permacultura, como principio rector tendiente a restablecer un vínculo racional de la sociedad con la naturaleza, a partir del estudio de una comunidad sustentada en dichos principios. A través de ello, se propende dar a conocer prácticas efectivas y reales que hacen a la sustentabilidad, fundamentadas en la necesidad y la revalorización de principios de reciprocidad entre los miembros de la sociedad y con la naturaleza, lo cual en el estudio de caso propuesto, se traduce en el significado de la vida en comunidad. En este sentido, resulta interesante destacar el auge que en la última década ha tenido la emergencia de espacios similares a lo largo y a lo ancho de Argentina, ya sea bajo la denominación de “ecoaldeas" o sitios-escuelas de Permacultura y las diferentes estrategias de difusión de la mencionada corriente, que en el caso del Jardín de los Presentes consiste en un proyecto denominado “Caravana de Permacultura y arte", el cual, en líneas generales, implica una escuela nómade para la difusión de la práctica permacultural como filosofía de vida . Acorde con ello, este trabajo constituye un aporte a su conocimiento, a partir de la sistematización de experiencias desarrolladas en uno de estos sitios, lo cual se espera contribuya al conocimiento de las diversas experiencias que existen en nuestro país.
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La podredumbre morena de los frutales de carozo causada por Monilinia spp. es una de las enfermedades más importantes a nivel mundial, tanto en cultivo como poscosecha. Para su control se emplean habitualmente fungicidas de síntesis. La tendencia mundial a exigir alimentos de óptima calidad que no perjudiquen a la salud ni al ambiente ha llevado a tratar de disminuir el empleo de este tipo de sustancias. El uso de productos naturales, no nocivos para el ser humano y obtenidos por metodologías sencillas podría representar una alternativa de manejo fitosanitario de los cultivos válida. Los extractos vegetales han sido reconocidos como agentes antimicrobianos desde la antigüedad y recientemente han atraído el interés científico. Éstos presentan una importante producción de metabolitos secundarios, que eventualmente podrían poseer efecto fungitóxico. El objetivo de la presente tesis, es por ello, estudiar la bioactividad de los extractos vegetales de distintas especies de la flora autóctona o presente desde antaño (chañar, jarilla, pájaro bobo, retortuño y aguaribay) hacia Monilinia fructicola, responsable de las principales pérdidas en cultivo y poscosecha de frutales de carozo. Para ello se determinó el efecto de los extractos sobre la germinación de conidios y el crecimiento miceliar de M. fructicola. La actividad sobre la germinación fue determinada agregando concentraciones crecientes del extracto a una suspensión de conidios de Monilinia fructicola. Luego se observó su efecto al microscopio óptico. La actividad sobre el crecimiento miceliar fue determinada por medio de la técnica de terreno envenenado y por el efecto de los compuestos volátiles del extracto a diferentes concentraciones. Todos los extractos estudiados presentaron en menor o mayor medida un efecto inhibitorio sobre la germinación y el crecimiento de tubo germinativo de conidios de M. fructicola. El extracto de jarilla (Larrea divaricata) fue el más efectivo a las concentraciones estudiadas registrándose un efecto dosis-dependiente. En los ensayos de crecimiento miceliar se observó que a bajas concentraciones de extracto de jarilla, este se vio estimulado, mientras que a concentraciones elevadas del extracto se registró inhibición del crecimiento miceliar del hongo. Por todo lo mencionado anteriormente, podría decirse que el extracto de jarilla permite inhibir al hongo M. fructicola in vitro.
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Los odontólogos que nos dedicamos a la atención de pacientes especiales sabemos que la técnica odontológica no es lo único que debemos conocer, ya que el manejo de distintas situaciones relacionadas con la discapacidad hace que nuestra tarea sea más compleja para Ilegar al logro de la salud bucal. Nos vamos a referir a una de esas situaciones en particular: la barrera que encontramos para el desarrollo de la comunicación a partir de la privación sensorial (visual o auditiva) o de dificultades motrices o intelectuales que presenta el paciente. La comunicación no tiene por qué ser solamente a través de la palabra oral o escrita, y debemos conocer la existencia de los sistemas alternativos de comunicación (SAAC). El término comunicación aumentativa describe las formas que usan las personas para comunicarse cuando no pueden hablar suficientemente claro, mientras que comunicación alternativa se refiere a métodos de comunicación usados para reemplazar completamente el habla.
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Presentación en el Seminario Acceso al aborto para mujeres sobrevivientes de violencia sexual. Guatemala, el 28 y 29 de octubre de 2014.