Canvia el paradigma del rellotge intern de les plantes

Una investigació dirigida per investigadors del Consell Superior d'Investigacions Científiques (CSIC), al Centre de Recerca en Agrigenòmica (CRAG) -consorci del CSIC, l'Institut de Recerca i Tecnologies Agroalimentàries (IRTA) i la UAB-, canvia radicalment el marc teòric que explicava com funciona el rellotge intern de les plantes que regula el seu cicle diari, l'anomenat rellotge circadiari. Els investigadors han demostrat un nou mecanisme de regulació pel qual una proteïna essencial del rellotge, coneguda amb el nom de TOC1, regula la ritmicitat en les plantes. El treball, que es publica a Science, canvia el model que explicava el funcionament del rellotge en plantes vigent al llarg dels últims 10 anys.Una investigación dirigida por investigadores del Consejo Superior de Investigaciones Científicas (CSIC), en el Centre de Recerca en Agrigenòmica (CRAG) -consorcio del CSIC, del Institut de Recerca i Tecnologies Agroalimentàries (IRTA) y la UAB-, cambia radicalmente el marco teórico que explicaba cómo funcionaba el reloj interno de las plantas que regula su ciclo diario, el llamado reloj circadiano. Los investigadores han demostrado un nuevo mecanismo de regulación por el cual una proteína esencial del reloj, conocida con el nombre de TOC1, regula la ritmicidad en las plantas. El trabajo, que se publica en Science, cambia el modelo que explicaba el funcionamiento del reloj en plantas vigente a lo largo de los últimos 10 años

Circadian clock signaling in Arabidopsis thaliana : From gene expression to physiology and development

The daily rotation of the earth on its axis leads to predictable periodic fluctuations of environmental conditions. Accordingly, most organisms have evolved an internal timing mechanism, the circadian clock, which is able to recognize these 24-hour rhythmic oscillations. In plants, the temporal synchronization of physiology with the environment is essential for successful plant growth and development. The intimate connection between light signaling pathways and the circadian oscillator allows the anticipation of the environmental transitions and the measurement of day-length as an indicator of changing seasons. In recent years, significant advances have been made in the genetic and molecular dissection of the plant circadian system, mostly in Arabidopsis thaliana. The overall plant clock organization is highly complex; the system seems to include several input pathways, tightly regulated central oscillators and a myriad of outputs. The molecular cloning and characterization of a number of clock components has greatly improved our view of the plant central oscillator and additional players will most likely come into place very soon. Molecular mechanisms underlying circadian clock function are also beginning to be characterized. The emerging model relies on negative feedback loops at the core of the oscillator. Additional levels of post-transcriptional and post-translational regulation also contribute to the generation and maintenance of the rhythms. Globally, these studies have shed new light on how the clock coordinates plant physiology and development with the daily and seasonal environmental cycles

Modelling the widespread effects of TOC1 signalling on the plant circadian clock and its outputs

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This work was supported by the European Commission FP7 Collaborative Project TiMet (project 245143). SynthSys is a Centre for Integrative and Systems Biology supported by BBSRC and EPSRC award D019621. Work in P.M. laboratory is supported by grants from the Ramón Areces Foundation, from the Spanish Ministry of Science and Innovation (MICINN) (BIO2010-16483) and from EUROHORCS (European Heads Of Research Councils) and the European Science Foundation (ESF) through the EURYI Award.Peer reviewedPublisher PD

El sincretismo lingúístico-cultural sefardí a la luz de dos textos aljamiados.

Sin resume

El romancero, entre la tradición oral y la imprenta popular

Se ofrece una panorámica sobre la historia y difusión del romancero como género de poesía narrativa, con especial atención a su éxito editorial en el siglo XVIPeer reviewe

Chromatin dynamics and transcriptional control of circadian rhythms in arabidopsis

Circadian rhythms pervade nearly all aspects of plant growth, physiology, and development. Generation of the rhythms relies on an endogenous timing system or circadian clock that generates 24-hour oscillations in multiple rhythmic outputs. At its bases, the plant circadian function relies on dynamic interactive networks of clock components that regulate each other to generate rhythms at specific phases during the day and night. From the initial discovery more than 13 years ago of a parallelism between the oscillations in chromatin status and the transcriptional rhythms of an Arabidopsis clock gene, a number of studies have later expanded considerably our view on the circadian epigenome and transcriptome landscapes. Here, we describe the most recent identification of chromatin-related factors that are able to directly interact with Arabidopsis clock proteins to shape the transcriptional waveforms of circadian gene expression and clock outputs. We discuss how changes in chromatin marks associate with transcript initiation, elongation, and the rhythms of nascent RNAs, and speculate on future interesting research directions in the field

El reloj circadiano de Arabidopsis thaliana: ¡las plantas siguen el ritmo!

The circadian clock perceives the environmental changes and measures the pass of time to generate rhythms in multiple biological processes. The clock plays a key role in sessile organisms like plants that need very precise and efficient responses to the environmental changes.El reloj circadiano percibe los cambios medioambientales y mide el paso del tiempo para generar ritmos en múltiples procesos biológicos. El reloj juega un papel particularmente importante en plantas, pues al ser organismos sésiles necesitan responder y adaptarse a los cambios medioambientales de forma muy precisa y eficiente

The EC-HDA9 complex rhythmically regulates histone acetylation at the TOC1 promoter in Arabidopsis

Circadian clocks are conserved time-keeper mechanisms in some prokaryotes and higher eukaryotes. Chromatin modification is emerging as key regulatory mechanism for refining core clock gene expression. Rhythmic changes in histone marks are closely associated to the TIMING OF CAB EXPRESSION 1 (TOC1) Arabidopsis clock gene. However, the chromatin-related modifiers responsible for these marks remain largely unknown. Here, we uncover that the chromatin modifier HISTONE DEACETYLASE 9 (HDA9) and the Evening complex (EC) component EARLY FLOWERING 3 (ELF3) directly interact to regulate the declining phase of TOC1 after its peak expression. We found that HDA9 specifically binds to the TOC1 promoter through the interaction with ELF3. The EC-HDA9 complex promotes H3 deacetylation at the TOC1 locus, contributing to suppressing TOC1 expression during the night, the time of EC function. Therefore, we have identified the mechanism by which the circadian clock intertwines with chromatin-related components to shape the circadian waveforms of gene expression in Arabidopsis

Una edición crítica de la quiná sefardí de La destrucción del Templo

The aim of this article is to offer a critical and annotated edition of the Sephardic dirge La destrucción del Templo ('the destruction of Jerusalem Jewish Temple') based on three sources written in Hebrew characters: two chapbooks printed in 1753 and ca. 1900, and a manuscript dated to the nineteenth century.En este artículo se presenta una edición crítica y detalladamente anotada de la endecha en lengua sefardí La destrucción del Templo, tomando como base los tres testimonios aljamiados en que nos ha llegado: dos libritos impresos en 1753 y ha. 1900, y un manuscrito del siglo XIX