Papers by berenice miranda
PLOS Genetics, 2011
The molecular mechanisms of plant recognition, colonization, and nutrient exchange between diazot... more The molecular mechanisms of plant recognition, colonization, and nutrient exchange between diazotrophic endophytes and plants are scarcely known. Herbaspirillum seropedicae is an endophytic bacterium capable of colonizing intercellular spaces of grasses such as rice and sugar cane. The genome of H. seropedicae strain SmR1 was sequenced and annotated by The Paraná State Genome Programme-GENOPAR. The genome is composed of a circular chromosome of 5,513,887 bp and contains a total of 4,804 genes. The genome sequence revealed that H. seropedicae is a highly versatile microorganism with capacity to metabolize a wide range of carbon and nitrogen sources and with possession of four distinct terminal oxidases. The genome contains a multitude of protein secretion systems, including type I, type II, type III, type V, and type VI secretion systems, and type IV pili, suggesting a high potential to interact with host plants. H. seropedicae is able to synthesize indole acetic acid as reflected by the four IAA biosynthetic pathways present. A gene coding for ACC deaminase, which may be involved in modulating the associated plant ethylene-signaling pathway, is also present. Genes for hemagglutinins/ hemolysins/adhesins were found and may play a role in plant cell surface adhesion. These features may endow H. seropedicae with the ability to establish an endophytic life-style in a large number of plant species.
Nutritional Neuroscience, 2009
The antiperoxidative properties of alpha-mangostin, a xanthone isolated from mangosteen fruit, we... more The antiperoxidative properties of alpha-mangostin, a xanthone isolated from mangosteen fruit, were tested for the first time in nerve tissue exposed to different toxic insults. Two reliable biological preparations (rat brain homogenates and synaptosomal P2 fractions) were exposed to the toxic actions of a free radical generator (ferrous sulfate), an excitotoxic agent (quinolinate), and a mitochondrial toxin (3-nitropropionate). alpha-Mangostin decreased the lipoperoxidative action of FeSO(4) in both preparations in a concentration-dependent manner, and completely abolished the peroxidative effects of quinolinate, 3-nitropropionate and FeSO(4) + quinolinate at all concentrations tested. Interestingly, when tested alone in brain homogenates, alpha-mangostin significantly decreased the lipoperoxidation even below basal levels. alpha-Mangostin also prevented the decreased reductant capacity of mitochondria in synaptosomal fractions. Our results suggest that alpha-mangostin exerts a robust antiperoxidative effect in brain tissue preparations probably through its properties as a free radical scavenger. In light of these findings, this antioxidant should be tested in other neurotoxic models involving oxidative stress.
Archives of Clinical Neuropsychology, 2009
Planta, 2004
Plant genes that are induced during the formation and function of a root nodule are called noduli... more Plant genes that are induced during the formation and function of a root nodule are called nodulin genes. Cloning and functional analysis of nodule-specific gene products are of valuable help in establishing the role and requirements of the host plant for the specificity and effectiveness of the symbiosis. A cDNA clone (nod22) was isolated from Phaseolus vulgaris L. (common bean) cDNA library derived from Rhizobium -infected roots. Nodulin 22 (Nod22) transcripts are accumulated from early to late stages in root nodule development. RT-PCR in situ studies indicated that Nod22 transcripts are highly accumulated in cortical, vascular bundle and infected cells. The deduced Nod22 protein contains a highly hydrophobic N-terminus, with signal peptide characteristics, and a C-terminal extension with high identity to the α-crystallin domains found in α-crystallin lens chaperone, and other small heat-shock proteins. These domains have not been previously described in other known nodulins, but have been observed in small heat-shock proteins found in plant tissues exposed to elevated temperature and oxidative stress. Nod22, when it is over-expressed in Escherichia coli, cells confers protection against oxidative stress suggesting its possible role in plant host protection from oxidative toxicity during the Rhizobium-legume symbiosis.
Systematic Parasitology, 1990
The genus Genarchella Travassos, Artigas & Pereira, 1928 is reinstated for some species from Sout... more The genus Genarchella Travassos, Artigas & Pereira, 1928 is reinstated for some species from South American fishes previously attributed to Halipegus Looss, 1899. Aspects of the morphology of G. genarchella Travassos, Artigas & Pereira, 1928 and G. parva Travassos, Artigas & Pereira, 1928 are redescribed. Astyanax bimaculatus, Moenkhausia doceana, Oligosarcus robustus and Salminus maxillosus are recorded as new hosts of G. parva, and H. cryptorchis Mané-Garzon & Gascón, 1973 and H. szidati Yamaguti, 1971 [= G. tropica of Szidat (1954)] are listed amongst new synonyms of this species. Aspects of the morphology of Thometrema magnifica (Szidat, 1954) and T. overstreeti (Brooks, Mayes & Thorson, 1979) are redescribed. T. rioplatense Lunaschi, 1989 is considered a synonym of T. overstreeti. New host-records of T. overstreeti are Pimelodus maculatus and Rhamdia sp. G. genarchella of Hamann (1986) is considered as synonym of T. overstreeti. Paravitellotrema Watson, 1976, Caballeroiella Lamothe-Argumedo, 1977 and Quadripaludus Jimenez, Guajardo & Briseno, 1981 are considered synonyms of Genarchella. The features distinguishing Halipegus, Genarchella and Thometrema Amato, 1968 are discussed.
Arquivos Brasileiros De Cardiologia, 2004
Cuando nacieron los gemelos, sus padres celebraron una fiesta en el templo de Apolo Timbreo, en l... more Cuando nacieron los gemelos, sus padres celebraron una fiesta en el templo de Apolo Timbreo, en las afueras de Troya. Al anochecer, regresaron al hogar, pero olvidaron a los bebés en el templo. A la mañana regresaron a recogerlos, los pequeños dormían sin percatarse que dos serpientes lamían sus órganos de los sentidos para purificarlos. Esta escena provocó la desesperación de los padres, que comenzaron a gritar angustiados, ocasionando que las serpientes huyeran. De este modo, Casandra y Héleno adquirieron el don de la profecía. La mitología no tiene una única versión acerca de la pitonisa y también le atribuyen la concesión del don a Apolo, quien se había enamorado de la joven por su gran belleza. El dios habría prometido concederle el don de la profecía, si ella aceptaba entregársele. La muchacha aceptó el trato, pero cuando estuvo iniciada en las artes adivinatorias, se negó a cumplir con su parte. Esto enfureció a Apolo, el que le escupió en la boca, retirándole el don de la persuasión, por lo que, sin importar lo que la adivina dijera, nadie podía creerle. Así pasaría sus días, viendo avecinarse las catástrofes sin poder hacer nada al respecto. Otras versiones de la mitología, afirmaban que cada vez que Casandra emitía una profecía, Apolo tomaba posesión de ella, provocándole convulsiones terribles. Las principales profecías de Casandra advertían sobre los peligros que su ciudad corría, y de haber sido oídas, habrían evitado los terribles sucesos que acontecieron. La pitonisa salvó de la muerte a su hermano Paris, cuando durante su juicio lo reconoció como hijo de Príamo. Cuando Helena llega a Troya con Paris, toda la ciudad está encantada con ella, menos Casandra, que vaticina que traerá la ruina para todos. La joven preconizó los peligros de la introducción del caballo de madera a la ciudad, al igual que el adivino Laoconte. Pero como era natural, nadie creyó en la muchacha. Para detener a Laoconte, que sí gozaba de credibilidad, Apolo envió unas serpientes para que lo devoraran junto a sus hijos. Esto permitió que los aqueos tomaran la ciudad. Durante el saqueo de Troya, Casandra se refugia en el templo de Palas Atenea, hasta donde es perseguida por Ayax, quien captura a la joven. Cuando los aqueos se reparten el botín de guerra, Agamanón recibe a Casandra, de la que se enamora locamente y se la lleva de regreso a Micenas. Cuando llegan, la esposa de Agamenón, Clitemnestra, en un rapto de celos mata a su marido y a la amante, ayudada por su propio amante, Egisto.
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Papers by berenice miranda