823 resultados para Mediterranea


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pt.1

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pt.2a

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Informe final. Ministerio de Educación y Ciencia, Dirección General de Investigación . Proyectos de I+D, Acciones Estratégicas y Eranets. 2006-2009.

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Background: Freshwater planarians are an attractive model for regeneration and stem cell research and have become a promising tool in the field of regenerative medicine. With the availability of a sequenced planarian genome, the recent application of modern genetic and high-throughput tools has resulted in revitalized interest in these animals, long known for their amazing regenerative capabilities, which enable them to regrow even a new head after decapitation. However, a detailed description of the planarian transcriptome is essential for future investigation into regenerative processes using planarians as a model system. Results: In order to complement and improve existing gene annotations, we used a 454 pyrosequencing approach to analyze the transcriptome of the planarian species Schmidtea mediterranea Altogether, 598,435 454-sequencing reads, with an average length of 327 bp, were assembled together with the ~10,000 sequences of the S. mediterranea UniGene set using different similarity cutoffs. The assembly was then mapped onto the current genome data. Remarkably, our Smed454 dataset contains more than 3 million novel transcribed nucleotides sequenced for the first time. A descriptive analysis of planarian splice sites was conducted on those Smed454 contigs that mapped univocally to the current genome assembly. Sequence analysis allowed us to identify genes encoding putative proteins with defined structural properties, such as transmembrane domains. Moreover, we annotated the Smed454 dataset using Gene Ontology, and identified putative homologues of several gene families that may play a key role during regeneration, such as neurotransmitter and hormone receptors, homeobox-containing genes, and genes related to eye function. Conclusions: We report the first planarian transcript dataset, Smed454, as an open resource tool that can be accessed via a web interface. Smed454 contains significant novel sequence information about most expressed genes of S. mediterranea. Analysis of the annotated data promises to contribute to identification of gene families poorly characterized at a functional level. The Smed454 transcriptome data will assist in the molecular characterization of S. mediterranea as a model organism, which will be useful to a broad scientific community.

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Background Freshwater planarians are an attractive model for regeneration and stem cell research and have become a promising tool in the field of regenerative medicine. With the availability of a sequenced planarian genome, the recent application of modern genetic and high-throughput tools has resulted in revitalized interest in these animals, long known for their amazing regenerative capabilities, which enable them to regrow even a new head after decapitation. However, a detailed description of the planarian transcriptome is essential for future investigation into regenerative processes using planarians as a model system. Results In order to complement and improve existing gene annotations, we used a 454 pyrosequencing approach to analyze the transcriptome of the planarian species Schmidtea mediterranea Altogether, 598,435 454-sequencing reads, with an average length of 327 bp, were assembled together with the ~10,000 sequences of the S. mediterranea UniGene set using different similarity cutoffs. The assembly was then mapped onto the current genome data. Remarkably, our Smed454 dataset contains more than 3 million novel transcribed nucleotides sequenced for the first time. A descriptive analysis of planarian splice sites was conducted on those Smed454 contigs that mapped univocally to the current genome assembly. Sequence analysis allowed us to identify genes encoding putative proteins with defined structural properties, such as transmembrane domains. Moreover, we annotated the Smed454 dataset using Gene Ontology, and identified putative homologues of several gene families that may play a key role during regeneration, such as neurotransmitter and hormone receptors, homeobox-containing genes, and genes related to eye function. Conclusions We report the first planarian transcript dataset, Smed454, as an open resource tool that can be accessed via a web interface. Smed454 contains significant novel sequence information about most expressed genes of S. mediterranea. Analysis of the annotated data promises to contribute to identification of gene families poorly characterized at a functional level. The Smed454 transcriptome data will assist in the molecular characterization of S. mediterranea as a model organism, which will be useful to a broad scientific community.

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Schmidtea mediterranea (Platyhelminthes, Tricladida, Continenticola) is found in scattered localities on a few islands and in coastal areas of the western Mediterranean. Although S. mediterranea is the object of many regeneration studies, little is known about its evolutionary history. Its present distribution has been proposed to stem from the fragmentation and migration of the Corsica-Sardinia microplate during the formation of the western Mediterranean basin, which implies an ancient origin for the species. To test this hypothesis, we obtained a large number of samples from across its distribution area. Using known and new molecular markers and, for the first time in planarians, a molecular clock, we analysed the genetic variability and demographic parameters within the species and between its sexual and asexual populations to estimate when they diverged. Results: A total of 2 kb from three markers (COI, CYB and a nuclear intron N13) was amplified from ~200 specimens. Molecular data clustered the studied populations into three groups that correspond to the west, central and southeastern geographical locations of the current distribution of S. mediterranea. Mitochondrial genes show low haplotype and nucleotide diversity within populations but demonstrate higher values when all individuals are considered. The nuclear marker shows higher values of genetic diversity than the mitochondrial genes at the population level, but asexual populations present lower variability than the sexual ones. Neutrality tests are significant for some populations. Phylogenetic and dating analyses show the three groups to be monophyletic, with the west group being the basal group. The time when the diversification of the species occurred is between ~20 and ~4 mya, although the asexual nature of the western populations could have affected the dating analyses. Conclusions: S. mediterranea is an old species that is sparsely distributed in a harsh habitat, which is probably the consequence of the migration of the Corsica-Sardinia block. This species probably adapted to temperate climates in the middle of a changing Mediterranean climate that eventually became dry and hot. These data also suggest that in the mainland localities of Europe and Africa, sexual individuals of S. mediterranea are being replaced by asexual individuals that are either conspecific or are from other species that are better adapted to the Mediterranean climate.

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Aquest segon volum de la revista Studia Ramazziniana mediterranea recull les Actes del Primer Congrés Català de Medicina del Treball, cel·lebrat a Barcelona del 4 al 7 d'abril de 1984.Les actes s'ordenen en quatre grups segons la temàtica tractada: Asbestosi, Invalideses, Dermatologia Laboral i Hepatitis.

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Aquest segon volum de la revista Studia Ramazziniana mediterranea recull les Actes del Primer Congrés Català de Medicina del Treball, cel·lebrat a Barcelona del 4 al 7 d'abril de 1984.Les actes s'ordenen en quatre grups segons la temàtica tractada: Asbestosi, Invalideses, Dermatologia Laboral i Hepatitis.

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Lista de especies de algas identificadas en los ambientes salobres constituidos por el Lago di Patria, una laguna salobre próxima a Nápoles y diversas zanjas y charcas próximas. El conjunto de la flora y las comunidades son comparables a las que se encuentran en lagunas análogas de las costas francesa y española.

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Se ha realizado un estudio de la comunidad de Cystoseira mediterránea a partir de ocho muestras recolectadas estacionalmente en dos localidades de la península del cabo de Creus (nordeste de España). Los resultados obtenidos se comentan en relación con las condiciones ambientales y se comparan con los obtenidos por otros autores.

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En 1945 J. BORJA, estudiando la flora de la Ribera valenciana, observó la presencia en los arrozales de varias especies particulares que, estudiadas detenidamente, fueron determinadas como Ammannia coccínea Rottb., A. verticillata Rottb., Bergia aquatica Roxb., etc. (v. FONT QUER, 1946; BORJA, 1950). Estas especies, alguna de las cuales era ya conocida de los arrozales de Portugal, no se habían indicado todavía de los que tan gran importancia alcanzan en el levante peninsular, en los cuales sin embargo deben existir desde tiempo algo antiguo, según acredita el hecho de que la indicada Bergia, por ejemplo, que los viejos campesinos conocen de toda la vida, posea incluso nombre popular (en Valencia la llaman alfabegueta, BORJA, 1. c ) .

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El estudio de ocho muestras recolectadas estacionalmente en dos localidades de la península del Cap de Creus (nordeste de España), ha permitido identificar un total de 81 táxones de algas epífitas de Cystoseira mediterranea Sauv. De éstas, Peyssonnelia rosa-marina í. saxicola Boudouresque y Denizot, Lithophyllum incrustans Phil., Pseudochlorodesmis furcellata (Zanardini) Boerg. y Feldmannophycus rayssiae (J. Feldmann y G. Feldmann) Augier y Boudouresque se encuentran exclusivamente sobre el disco basal del forófito, Jania rubens (L.) Lamour. es la especie más abundante en el estipe y Ceramium rubrum (Huds.) C. Agardh y Dermatolithon pustulatum (Lamour.) Foslie dominan sobre las ramas. Por otra parte, el supergrupo ecológico Fotófilo Infralitoral (FI) es el mejor representado en las tres partes del talo del forófito, si bien cabe señalar que sobre el disco basal se desarrolla un grupo de algas esciófilas muy característico.

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We performed a study on the specific composition, structure, and dynamics of two Cystoseira mediterranea communities from the north-western Mediterranean submitted to different degrees of pollution. The structural complexity (species richness, specific distribution, and species and pattern diversity) and biomass production were lower in the polluted site. In this station, opportunistic algae (mainly Ulva rigida) loomed, and Mesophyllum lichenoides and some encrusting brown algae increased their cover. Other species (Jania rubens, and some Ceramiales) decreased their abundance when compared with the polluted site

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Nimeketiedot nimiönkehyksissä

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