211 research outputs found

    PHO1 Exports Phosphate from the Chalazal Seed Coat to the Embryo in Developing Arabidopsis Seeds.

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    Seed production requires the transfer of nutrients from the maternal seed coat to the filial endosperm and embryo. Because seed coat and filial tissues are symplasmically isolated, nutrients arriving in the seed coat via the phloem must be exported to the apoplast before reaching the embryo. Proteins implicated in the transfer of inorganic phosphate (Pi) from the seed coat to the embryo are unknown despite seed P content being an important agronomic trait. Here we show that the Arabidopsis Pi exporters PHO1 and PHOH1 are expressed in the chalazal seed coat (CZSC) of developing seeds. PHO1 is additionally expressed in developing ovules. Phosphorus (P) content and Pi flux between the seed coat and embryo were analyzed in seeds from grafts between WT roots and scions from either pho1, phoh1, or the pho1 phoh1 double mutant. Whereas P content and distribution between the seed coat and embryo in fully mature dry seeds of these mutants are similar to the WT, at the mature green stage of seed development the seed coat of the pho1 and pho1 phoh1 mutants, but not of the phoh1 mutant, retains approximately 2-fold more P than its WT control. Expression of PHO1 under a CZSC-specific promoter complemented the seed P distribution phenotype of the pho1 phoh1 double mutant. CZSC-specific down-expression of PHO1 also recapitulated the seed P distribution phenotype of pho1. Together, these experiments show that PHO1 expression in the CZSC is important for the transfer of P from the seed coat to the embryo in developing seeds

    Intrachromosomal excision of a hybrid Ds element induces large genomic deletions in Arabidopsis

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    Transposon activity is known to cause chromosome rearrangements in the host genome. Surprisingly, extremely little is known about Dissociation (Ds)-induced chromosome rearrangements in Arabidopsis, where Ds is intensively used for insertional mutagenesis. Here, we describe three Arabidopsis mutants with reduced fertility and propose that excision of a hybrid Ds element induced a large genomic deletion flanking Ds. In the mutants anat and haumea, the deletion mechanism consists of a local Ds transposition from replicated into unreplicated DNA followed by Ds excision, where one end of the newly transposed element and one end of the Ds transposon at the donor site served as substrate for transposase. Excision of this hybrid element reminiscent of a macrotransposon leads to loss of the chromosomal piece located between the two ends, including one full Ds element and the flanking genomic sequence. This mechanism was found to be responsible for several other deletions and occurs at a genetically trackable frequency. Thus, it could be applied to efficiently generate deletions of various sizes in the vicinity of any existing Ds element present in the genome. In the mutant tons missing, a mechanism that involves endogenous repetitive sequences caused a large flanking deletion at a position unlinked to the starter locus. Our study of Ds transposition in Arabidopsis revealed previously undescribed mechanisms that lead to large genomic deletions flanking Ds elements, which may contribute to genome dynamics and evolution

    Tsunami: a movie for the tsunami risk reduction in Italy

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    Italy is a country well known for the seismic and volcanic hazard. As a matter of fact the first seismological and volcanological observations were done in since the Roman times. However, a similarly great hazard, although not well recognized, is posed by the occurrence of tsunami waves along the Italian coastline. This is testified by a rich catalogue and by field evidence of deposits left over by pre- and historical tsunamis, even in places today considered safe. This observation is of great importance since many of the areas affected by tsunamis in the past are today touristic places. The Italian tsunamis can be caused by different sources: 1- off-shore or near coast in-land earthquakes (e.g. 1627, 1783 and 1908 events); 2- very large earthquakes on distant sources in the Mediterranean (e.g. the 365 Crete subduction zone earthquake); 3- submarine volcanic explosion in the Tyrrhenian sea; 4- submarine landslides triggered by earthquakes and volcanic activity (e.g. 2002 Stromboli landslide). The consequence of such a wide spectrum of sources is that an important part of the more than 7000 km long Italian coast line is exposed to the tsunami risk, and thousands of inhabitants (with numbers increasing during summer) live near hazardous coasts. In order to reduce this risk and following the emotional impact of the december 2004 Sumatra earthquake and tsunami, we developed an outreach program consisting in talks given by scientists and in a movie, both exploring the causes of the tsuanami waves, how do they propagate in deep and shallow waters, and what are the effects on the coasts. Hints are also given on the most dangerous Italian coasts (as deduced by scientific studies), and how to behave in the case of a tsunami approaching the coast. These seminars are open to the general publics, but special programs are developed with schools of all grades. In this talk we want to present the movie used during the seminars and scientific expositions, that was realized from a previous 3D version originally developed for science festivals

    Volcanoes: effusions and explosions. Interactive exhibits to understand how volcanoes work

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    The Educational & Outreach Group (EOG) of the Istituto Nazionale di Geofisica & Vulcanologia created a portable museum to provide educational opportunities in volcanology, volcanic risk and Earth science for students and visitors. The EOG developed this project for the "Festival della Scienza", organized in Genoa, Italy, in October - November, 2007, which was a parade of over 200 events, including scientific and technological exhibitions, workshops, meetings, lectures, books and video presentations. In this museum visitors can successively see many posters and movies and play with interactive exhibits. A little 3D-movie shows the Big Bang, the formation of Solar System and, in particular the formation of the Earth. Many interactive exhibits illustrate why, where and when earthquakes and volcanic eruptions occur around the world and allow to introduce the visitor to the plate tectonics theory. A 3D magnetic plate tectonic puzzle can be put down and reconstructed by visitors to understand the Earth’s surface configuration. Then two other 3D Earth models show what drives the plates and the inner Earth structure. An interactive program illustrates where and when earthquakes and volcanic eruptions occur in accelerated time on maps of various areas around the world. Playing with a block diagram it is possible to produce an earthquake along a 1 meter long strike slip fault in a destroying all the man-made constructions close to it. A little movie introduces to volcanoes’ world. Two small interactive exhibits allow visitors to understand the mechanism for the explosive and the effusive eruptions. Two other exciting interactive exhibits allow visitors to “create” two different eruptions: the explosive and the effusive ones. It is possible to get inside a volcano (a 2 meter high interactive exhibit) to attend an eruption from the magmatic chamber to the Earth surface. A big hall is completed dedicated to Italian volcanoes (Vesuvio, Campi Flegrei, Etna, Stromboli, Vulcano, Colli Albani); some of them are reproduced with 3D models or described by short movies. The museum finishes with the visit of the volcanic survey hall of Stromboli, seeing - in real time - seismic data, three different webcams, geochemical and strain data. The INGV Museum had remarkably successful, reaching more than 7,500 children and adults yet in 13 days, also thanks to 30 volcanologists as very special guides. The Educational & Outreach Group: M. Pignone, A. Tertulliani, M. De Lucia, M. Di Vito, P. Landi, P. Madonia, M. Martini, R. Nave, M. Neri, P. Scarlato, J. Taddeucci, R. Moschillo, S. Tarquini, G. Vilardo, A. Bonforte, L. Calderone, F. Cannavò, W. De Cesare, P. Ficeli, S. Inguaggiato, M. Mattia, G. Puglisi, S. Morici, D. Reitano, D. Richichi, G. Scarpato, B. Angioni, F. Di Laura, S. Palone, D. Riposati

    Whole-genome analysis of histone H3 lysine 27 trimethylation in Arabidopsis

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    Trimethylation of histone H3 lysine 27 (H3K27me3) plays critical roles in regulating animal development, and in several cases, H3K27me3 is also required for the proper expression of developmentally important genes in plants. However, the extent to which H3K27me3 regulates plant genes on a genome-wide scale remains unknown. In addition, it is not clear whether the establishment and spreading of H3K27me3 occur through the same mechanisms in plants and animals. We identified regions containing H3K27me3 in the genome of the flowering plant Arabidopsis thaliana using a high-density whole-genome tiling microarray. The results suggest that H3K27me3 is a major silencing mechanism in plants that regulates an unexpectedly large number of genes in Arabidopsis (~4,400), and that the maintenance of H3K27me3 is largely independent of other epigenetic pathways, such as DNA methylation or RNA interference. Unlike in animals, where H3K27m3 occupies large genomic regions, in Arabidopsis, we found that H3K27m3 domains were largely restricted to the transcribed regions of single genes. Furthermore, unlike in animals systems, H3K27m3 domains were not preferentially associated with low-nucleosome density regions. The results suggest that different mechanisms may underlie the establishment and spreading of H3K27me3 in plants and animals

    Vulcani: esplosioni ed effusioni

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    Si tratta dei pannelli realizzati per la mostraVulcani: Esplosioni ed effusioni Festival della Scienza di Genova 2007 Palazzo Ducale – Sottoporticato, Genova Una nuova mostra interattiva delll’Istituto Nazionale di Geofisica e Vucanologia, alla scoperta dei segreti del nostro pianeta e del mondo spettacolare dei vulcani. Organizzato come un “racconto”, è un lungo viaggio dalla nascita Terra ad oggi che aiuta a comprendere il ruolo fondamentale dei vulcani nella storia del nostro pianeta. Inizia con una proiezione 3d seguita da un filmato spettacolare e coinvolgente di eruzioni vulcaniche. Nella mostra si incontrano poi un grande modello di vulcano che può essere “acceso” in modalità interattiva, producendo un’eruzione esplosiva con gran fragore, sezioni di vulcano per scoprire “cosa c’è sotto”, plastici associati ad una speciale proiezione che permette di visualizzare sia l’eruzione sia l’interno del vulcano. E ancora rocce vulcaniche e un laboratorio per esperienze guidate, per capire il meccanismo che provoca l’eruzione, studiando il legame tra gas, pressione ed esplosione, anche utilizzando ulteriori modellini di vulcano. Il fatto che spesso le eruzioni vulcaniche siano accompagnate da attività sismica ci introduce alla parte finale della mostra, dedicata ai terremoti. L’obiettivo complessivo della mostra è quello di comunicare e far comprendere l’importanza del lavoro di ricerca e di controllo che svolge l’INGV e il riflesso che questo ha nella vita di ciascuno di noi. Si tratta, in sostanza, di “raccontare” le attività scientifiche svolte dall’Istituto inquadrandole dal punto di vista del visitatore.Con i contributi dell’Associazione per il Festival della Scienza e del Dipartimento della Protezione CivilePublished5.8. TTC - Formazione e informazionereserve

    Using earthquakes to uncover the Earth's inner secrets: interactive exhibits for geophysical education

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    The Educational &amp; Outreach Group (E&amp;O Group) of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) designed a portable museum to bring on the road educational activities focused on seismology, seismic hazard and Earth science. This project was developed for the first edition of the Science Festival organized in Genoa, Italy, in 2003. <P style=&quot;line-height: 20px;&quot;> The museum has been mainly focused to school students of all ages and explains the main topics of geophysics through posters, movie and slide presentations, and exciting interactive experiments. This new INGV museum has been remarkably successful, being visited by more than 8000 children and adults during the 10 days of the Science Festival. It is now installed at the INGV headquarters in Rome and represents the main attraction during the visits of the schools all year round

    Using earthquakes to uncover the Earth's inner secrets: interactive exhibits for geophysical education

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    International audienceThe Educational & Outreach Group (E&O Group) of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) designed a portable museum to bring on the road educational activities focused on seismology, seismic hazard and Earth science. This project was developed for the first edition of the Science Festival organized in Genoa, Italy, in 2003. The museum has been mainly focused to school students of all ages and explains the main topics of geophysics through posters, movie and slide presentations, and exciting interactive experiments. This new INGV museum has been remarkably successful, being visited by more than 8000 children and adults during the 10 days of the Science Festival. It is now installed at the INGV headquarters in Rome and represents the main attraction during the visits of the schools all year round

    Terremoti e Maremoti

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    Published1.1. TTC - Monitoraggio sismico del territorio nazionale5.9. Formazione e informazioneope
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