Conditional Synergism between Cryptochrome 1 and Phytochrome B Is Shown by the Analysis of phyA, phyB, and hy4 Simple, Double, and Triple Mutants in Arabidopsis

Wild-type or phyA, phyB, or hy4 mutant Arabidopsis seedlings lacking phytochrome A (phyA), phytochrome B (phyB), or cryptochrome 1 (cry1), respectively, and the double and triple mutants were used in combination with blue-light treatments given simultaneously with red or far-red light. We investigated the interaction between phytochromes and cry1 in the control of hypocotyl growth and cotyledon unfolding. Under conditions deficient for cry1 (short exposures to blue light) or phyB (far-red background), these photoreceptors acted synergistically: Under short exposures to blue light (3 h/d) added to a red-light background, cry1 activity required phyB (e.g. the hy4 mutant was taller than the wild type but the phyBhy4 mutant was not taller than the phyB mutant). Under prolonged exposures to blue light (24 h/d) added to a far-red light background, phyB activity required cry1 (e.g. the phyAphyB mutant was taller than the phyA mutant but the phyAphyBhy4 mutant was not taller than the phyAhy4 mutant). Under more favorable light inputs, i.e. prolonged exposures to blue light added to a red-light background, the effects of cry1 and phyB were independent. Thus, the synergism between phyB and cry1 is conditional. The effect of cry1 was not reduced by the phyA mutation under any tested light condition. Under continuous blue light the triple mutant phyAphyBhy4 showed reduced hypocotyl growth inhibition and cotyledon unfolding compared with the phyAphyB mutant. The action of cry1 in the phyAphyB double mutant was higher under the red-light than the far-red-light background, indicating a synergistic interaction between cry1 and phytochromes C, D, or E; however, a residual action of cry1 independent of any phytochrome is likely to occur.

Different Phototransduction Kinetics of Phytochrome A and Phytochrome B in Arabidopsis thaliana1

The kinetics of phototransduction of phytochrome A (phyA) and phytochrome B (phyB) were compared in etiolated Arabidopsis thaliana seedlings. The responses of hypocotyl growth, cotyledon unfolding, and expression of a light-harvesting chlorophyll a/b-binding protein of the photosystem II gene promoter fused to the coding region of β-glucuronidase (used as a reporter enzyme) were mediated by phyA under continuous far-red light (FR) and by phyB under continuous red light (R). The seedlings were exposed hourly either to n min of FR followed by 60 minus n min in darkness or to n min of R, 3 min of FR (to back-convert phyB to its inactive form), and 57 minus n min of darkness. For the three processes investigated here, the kinetics of phototransduction of phyB were faster than that of phyA. For instance, 15 min R h−1 (terminated with a FR pulse) were almost as effective as continuous R, whereas 15 min of FR h−1 caused less than 30% of the effect of continuous FR. This difference is interpreted in terms of divergence of signal transduction pathways downstream from phyA and phyB.

Identification of novel genes in Drosophila reveals the complex regulation of early gene activity in the mesoderm.

Two zygotic genes, twist and snail, are indispensable for the correct establishment of the mesoderm primordium in the early Drosophila embryo. They are also needed for morphogenesis and differentiation of the mesoderm. Both genes code for transcription factors with different, albeit complementary, functions. Therefore, to understand the early development of the mesoderm, it will be necessary to identify and study the genes regulated by twist and snail. We have searched for downstream genes using a subtractive cDNA library enriched in sequences expressed in the mesoderm. We have isolated sequences that correspond to 13 novel early mesoderm genes. These novel genes show a variety of expression patterns and also differ in their dependence on twist and snail functions. This indicates that the regulation of early gene activity in the mesoderm is more complex than previously thought.

La organización de los juegos olímpicos como elemento de configuración de regímenes urbanos: Barcelona 1992 como estudio de caso

The games were an opportunity for Spain to show to the world as a modern, wealthy and democratic country of Western Europe, that successfully accomplished 15 years of political transition and dealt with identity issues. But the games also were a window of opportunity for the complete “reinvention” of Barcelona at all levels (political, economical, social and urbanistic) and laid the foundations for the development of the city in the next decades. This research argues that this process of “reinvention of the city” can be explained for three factors: 1) A policy coalition involving key economic and social actors under the leadership of Barcelona‟s Major, which led to a new urban regime. 2) An intergovernmental game that privileged the cooperation between the federal and urban government, as well as the international sports institutions 3) An understanding of the Olympic infrastructures not only as a guarantee for the success of the event, but as the starting point for a new model of urban and identity development regarding to the XXI siècle. The main objective of the research is to analyze the possible application of urban regime approach to different local government systems of the US by analyzing a case study, Barcelona...

La basílica y el baptisterio de Tolmo de Minateda (Hellín, Albacete)

Se presenta el complejo religioso exhumado en la parte alta de la ciudad altomedieval del Tolmo de Minateda (Hellín, Albacete), correspondiente a la Madînat Iyih de las fuentes árabes y, en opinión de los autores, a la sede episcopal Eiotana/Elotana creada a principios del siglo VII. El conjunto religioso está compuesto por una basílica de tres naves con ábside semicircular y un baptisterio anexo situado a los pies del edificio, también con distribución tripartita. En este artículo se estudia detalladamente el baptisterio, así como las distintas remodelaciones de la piscina bautismal, y se propone una restitución del espacio litúrgico.

Tres décadas de proyectos e investigaciones arqueológicas en la Universidad de Alicante

En las últimas décadas, la Arqueología de investigación realizada desde el Área de Arqueología de la Universidad de Alicante ha realizado considerables aportaciones en el ámbito transversal de la Arqueología, desde el convencimiento de que esta disciplina no debe estar atada a ningún periodo histórico concreto. Así, se ha propuesto una nueva visión urbanística de los primeros tiempos de la cultura ibérica y de su relación con la fenicia; se han identificado y estudiado ciudades romanas hasta ahora desconocidas y se han desarrollado modelos del cambio cultural que desde la tardía Antigüedad lleva al Medievo.

Fibrose quística : fenótipo e genótipo : descrição de caso clínico

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Disfunção erétil

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Cielos y llanuras, poesías.

Mode of access: Internet.

Humildad, poesías.

Mode of access: Internet.