101 research outputs found

    Primer design for the amplification of the ammonium transporter genes from the uncultured haptophyte algal species symbiotic with the marine nitrogen-fixing cyanobacterium UCYN-A1

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    The multiple symbiotic partnerships between closely related species of the haptophyte algae Braarudosphaera bigelowii and the nitrogen-fixing cyanobacteria Candidatus Atelocyanobacterium thalassa (UCYN-A) contribute importantly to the nitrogen and carbon cycles in vast areas of the ocean. The diversity of the eukaryotic 18S rDNA phylogenetic gene marker has helped to identify some of these symbiotic haptophyte species, yet we still lack a genetic marker to assess its diversity at a finer scale. One of such genes is the ammonium transporter (amt) gene, which encodes the protein that might be involved in the uptake of ammonium from UCYN-A in these symbiotic haptophytes. Here, we designed three specific PCR primer sets targeting the amt gene of the haptophyte species (A1-Host) symbiotic with the open ocean UCYN-A1 sublineage, and tested them in samples collected from open ocean and near-shore environments. Regardless of the primer pair used at Station ALOHA, which is where UCYN-A1 is the pre-dominant UCYN-A sublineage, the most abundant amt amplicon sequence variant (ASV) was taxonomically classified as A1-Host. In addition, two out of the three PCR primer sets revealed the existence of closely-related divergent haptophyte amt ASVs (>95% nucleotide identity). These divergent amt ASVs had higher relative abundances than the haptophyte typically associated with UCYN-A1 in the Bering Sea, or co-occurred with the previously identified A1-Host in the Coral Sea, suggesting the presence of new diversity of closely-related A1-Hosts in polar and temperate waters. Therefore, our study reveals an overlooked diversity of haptophytes species with distinct biogeographic distributions partnering with UCYN-A, and provides new primers that will help to gain new knowledge of the UCYN-A/haptophyte symbiosis

    Delineating ecologically significant taxonomic units from global patterns of marine picocyanobacteria

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    Prochlorococcus and Synechococcus are the two most abundant and widespread phytoplankton in the global ocean. To better understand the factors controlling their biogeography, a reference database of the high-resolution taxonomic marker petB, encoding cytochrome b6, was used to recruit reads out of 109 metagenomes from the Tara Oceans expedition. An unsuspected novel genetic diversity was unveiled within both genera, even for the most abundant and well-characterized clades, and 136 divergent petB sequences were successfully assembled from metagenomic reads, significantly enriching the reference database. We then defined Ecologically Significant Taxonomic Units (ESTUs)—that is, organisms belonging to the same clade and occupying a common oceanic niche. Three major ESTU assemblages were identified along the cruise transect for Prochlorococcus and eight for Synechococcus. Although Prochlorococcus HLIIIA and HLIVA ESTUs codominated in irondepleted areas of the Pacific Ocean, CRD1 and the yet-to-be cultured EnvB were the prevalent Synechococcus clades in this area, with three different CRD1 and EnvB ESTUs occupying distinct ecological niches with regard to iron availability and temperature. Sharp community shifts were also observed over short geographic distances—for example, around the Marquesas Islands or between southern Indian and Atlantic Oceans—pointing to a tight correlation between ESTU assemblages and specific physico-chemical parameters. Together, this study demonstrates that there is a previously overlooked, ecologically meaningful, fine-scale diversity within some currently defined picocyanobacterial ecotypes, bringing novel insights into the ecology, diversity, and biology of the two most abundant phototrophs on Earth

    Viral to metazoan marine plankton nucleotide sequences from the Tara Oceans expedition

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    A unique collection of oceanic samples was gathered by the Tara Oceans expeditions (2009–2013), targeting plankton organisms ranging from viruses to metazoans, and providing rich environmental context measurements. Thanks to recent advances in the field of genomics, extensive sequencing has been performed for a deep genomic analysis of this huge collection of samples. A strategy based on different approaches, such as metabarcoding, metagenomics, single-cell genomics and metatranscriptomics, has been chosen for analysis of size-fractionated plankton communities. Here, we provide detailed procedures applied for genomic data generation, from nucleic acids extraction to sequence production, and we describe registries of genomics datasets available at the European Nucleotide Archive (ENA, www.ebi.ac.uk/ena). The association of these metadata to the experimental procedures applied for their generation will help the scientific community to access these data and facilitate their analysis. This paper complements other efforts to provide a full description of experiments and open science resources generated from the Tara Oceans project, further extending their value for the study of the world’s planktonic ecosystems

    Global diversity and biogeography of deep-sea pelagic prokaryotes

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    The deep-sea is the largest biome of the biosphere, and contains more than half of the whole ocean/'s microbes. Uncovering their general patterns of diversity and community structure at a global scale remains a great challenge, as only fragmentary information of deep-sea microbial diversity exists based on regional-scale studies. Here we report the first globally comprehensive survey of the prokaryotic communities inhabiting the bathypelagic ocean using high-throughput sequencing of the 16S rRNA gene. This work identifies the dominant prokaryotes in the pelagic deep ocean and reveals that 50{\%} of the operational taxonomic units (OTUs) belong to previously unknown prokaryotic taxa, most of which are rare and appear in just a few samples. We show that whereas the local richness of communities is comparable to that observed in previous regional studies, the global pool of prokaryotic taxa detected is modest (\~{}3600 OTUs), as a high proportion of OTUs are shared among samples. The water masses appear to act as clear drivers of the geographical distribution of both particle-attached and free-living prokaryotes. In addition, we show that the deep-oceanic basins in which the bathypelagic realm is divided contain different particle-attached (but not free-living) microbial communities. The combination of the aging of the water masses and a lack of complete dispersal are identified as the main drivers for this biogeographical pattern. All together, we identify the potential of the deep ocean as a reservoir of still unknown biological diversity with a higher degree of spatial complexity than hitherto considered.En prensa8,951

    Towards precision medicine: defining and characterizing adipose tissue dysfunction to identify early immunometabolic risk in symptom-free adults from the GEMM family study

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    Interactions between macrophages and adipocytes are early molecular factors influencing adipose tissue (AT) dysfunction, resulting in high leptin, low adiponectin circulating levels and low-grade metaflammation, leading to insulin resistance (IR) with increased cardiovascular risk. We report the characterization of AT dysfunction through measurements of the adiponectin/leptin ratio (ALR), the adipo-insulin resistance index (Adipo-IRi), fasting/postprandial (F/P) immunometabolic phenotyping and direct F/P differential gene expression in AT biopsies obtained from symptom-free adults from the GEMM family study. AT dysfunction was evaluated through associations of the ALR with F/P insulin-glucose axis, lipid-lipoprotein metabolism, and inflammatory markers. A relevant pattern of negative associations between decreased ALR and markers of systemic low-grade metaflammation, HOMA, and postprandial cardiovascular risk hyperinsulinemic, triglyceride and GLP-1 curves was found. We also analysed their plasma non-coding microRNAs and shotgun lipidomics profiles finding trends that may reflect a pattern of adipose tissue dysfunction in the fed and fasted state. Direct gene differential expression data showed initial patterns of AT molecular signatures of key immunometabolic genes involved in AT expansion, angiogenic remodelling and immune cell migration. These data reinforce the central, early role of AT dysfunction at the molecular and systemic level in the pathogenesis of IR and immunometabolic disorders

    Salud de los trabajadores

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    Actividad física y su relación con los factores de riesgo cardiovascular de carteros chilenosAnálisis de resultados: riesgos psicosociales en el trabajo Suceso-Istas 21 en Cesfam QuellónAusentismo laboral por enfermedades oftalmológicas, Chile 2009Brote de diarreas por norovirus, posterremoto-tsunami, Constitución, Región del MauleCalidad de vida en profesionales de la salud pública chilenaCaracterización del reposo laboral en personal del SSMN durante el primer semestre de 2010Concentración de nicotina en pelo en trabajadores no fumadores expuestos a humo de tabaco ambientalCondiciones de trabajo y bienestar/malestar docente en profesores de enseñanza media de SantiagoDisfunción auditiva inducida por exposición a xilenoErgonomía aplicada al estudio del síndrome de dolor lumbar en el trabajoEstimación de la frecuencia de factores de riesgo cardiovascular en trabajadores de una empresa mineraExposición a plaguicidas inhibidores de la acetilcolinesterasa en Colombia, 2006-2009Factores de riesgo y daños de salud en conductores de una empresa peruana de transporte terrestre, 2009Las consecuencias de la cultura en salud y seguridad ocupacional en una empresa mineraPercepción de cambios en la práctica médica y estrategias de afrontamientoPercepción de la calidad de vida en la Universidad del BiobíoPesos máximos aceptables para tareas de levantamiento manual de carga en población laboral femeninaRiesgo coronario en trabajadores mineros según la función de Framingham adaptada para la población chilenaTrastornos emocionales y riesgo cardiovascular en trabajadores de la salu

    Viral to metazoan marine plankton nucleotide sequences from the Tara Oceans expedition

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    A unique collection of oceanic samples was gathered by the Tara Oceans expeditions (2009-2013), targeting plankton organisms ranging from viruses to metazoans, and providing rich environmental context measurements. Thanks to recent advances in the field of genomics, extensive sequencing has been performed for a deep genomic analysis of this huge collection of samples. A strategy based on different approaches, such as metabarcoding, metagenomics, single-cell genomics and metatranscriptomics, has been chosen for analysis of size-fractionated plankton communities. Here, we provide detailed procedures applied for genomic data generation, from nucleic acids extraction to sequence production, and we describe registries of genomics datasets available at the European Nucleotide Archive (ENA, www.ebi.ac.uk/ena). The association of these metadata to the experimental procedures applied for their generation will help the scientific community to access these data and facilitate their analysis. This paper complements other efforts to provide a full description of experiments and open science resources generated from the Tara Oceans project, further extending their value for the study of the world's planktonic ecosystems

    Diversity, ecology and evolution of marine diazotrophic microorganisms

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    Memoria de tesis doctoral presentada por Francisco Miguel Cornejo Castillo para optar al grado de Doctor en Ciencias del Mar por la Universitat Politècnica de Catalunya (UPC), realizada bajo la dirección de la Dra. Silvia González Acinas del Institut de Ciències del Mar (ICM-CSIC).-- 177 pages[EN] Biological N2 fixation, the reduction of dinitrogen (N2) gas to biologically available nitrogen, is a fundamental process since it represents a source of new nitrogen for marine life in areas where this important element can be limiting, supporting primary productivity and thus biological carbon export to the deep ocean. This process is performed by the nitrogen-fixing prokaryotic microorganisms (the so-called diazotrophs). However, very little is still known about the identity and ecology of diazotrophs, which largely limits our capacity to understand the global significance of this process, and to predict potential variations in nitrogen fixation upon changes in environmental conditions. In this thesis, we aimed at improving the knowledge on the diversity, ecology and evolution of the marine nitrogen-fixing microorganisms in the open ocean. [...][ES] La fijación biológica de nitrógeno, es decir, la reducción del nitrógeno (N2) a amonio, es un proceso fundamental ya que representa una fuente de nitrógeno para la vida marina en áreas donde este elemento es limitante, posibilitando la producción primaria y por tanto la exportación de carbono al océano profundo. Este proceso se lleva a cabo por microorganismos procariotas, los llamados diazotrofos. Sin embargo, aún sabemos muy poco sobre la identidad y la ecología de estos microorganismos, lo que limita enormemente nuestra comprensión de la importancia global de este proceso, y nuestra capacidad de predecir cambios en la fijación de N2 ligados a cambios en el ambiente. El objetivo de esta tesis, por tanto, fue ahondar en el conocimiento de la diversidad, ecología y evolución de los microorganismos diazotrofos en el océano. [...]Peer Reviewe
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