ALBERT

Description: Microbes and their viruses drive myriad processes across ecosystems ranging from oceans and soils to bioreactors and humans. Despite this importance, microbial diversity is only now being mapped at scales relevant to nature, while the viral diversity associated with any particular host remains little researched. Here we quantify host-associated viral diversity using viral-tagged metagenomics, which links viruses to specific host cells for high-throughput screening and sequencing. In a single experiment, we screened 10(7) Pacific Ocean viruses against a single strain of Synechococcus and found that naturally occurring cyanophage genome sequence space is statistically clustered into discrete populations. These population-based, host-linked viral ecological data suggest that, for this single host and seawater sample alone, there are at least 26 double-stranded DNA viral populations with estimated relative abundances ranging from 0.06 to 18.2%. These populations include previously cultivated cyanophage and new viral types missed by decades of isolate-based studies. Nucleotide identities of homologous genes mostly varied by less than 1% within populations, even in hypervariable genome regions, and by 42-71% between populations, which provides benchmarks for viral metagenomics and genome-based viral species definitions. Together these findings showcase a new approach to viral ecology that quantitatively links objectively defined environmental viral populations, and their genomes, to their hosts.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Deng, Li -- Ignacio-Espinoza, J Cesar -- Gregory, Ann C -- Poulos, Bonnie T -- Weitz, Joshua S -- Hugenholtz, Philip -- Sullivan, Matthew B -- England -- Nature. 2014 Sep 11;513(7517):242-5. doi: 10.1038/nature13459. Epub 2014 Jul 13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85719, USA [2] Helmholtz Zentrum Munchen-German Research Center for Environmental Health, Institute of Groundwater Ecology, Neuherberg 85764, Germany. [3]. ; 1] Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85719, USA [2]. ; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85719, USA. ; 1] School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332, USA [2] School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA. ; Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences &Institute for Molecular Bioscience, The University of Queensland, St Lucia QLB 4072, Australia. ; 1] Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85719, USA [2] Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85719, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25043051" target="_blank"〉PubMed〈/a〉

Description: Viruses influence ecosystems by modulating microbial population size, diversity, metabolic outputs, and gene flow. Here, we use quantitative double-stranded DNA (dsDNA) viral-fraction metagenomes (viromes) and whole viral community morphological data sets from 43 Tara Oceans expedition samples to assess viral community patterns and structure in the upper ocean. Protein cluster cataloging defined pelagic upper-ocean viral community pan and core gene sets and suggested that this sequence space is well-sampled. Analyses of viral protein clusters, populations, and morphology revealed biogeographic patterns whereby viral communities were passively transported on oceanic currents and locally structured by environmental conditions that affect host community structure. Together, these investigations establish a global ocean dsDNA viromic data set with analyses supporting the seed-bank hypothesis to explain how oceanic viral communities maintain high local diversity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Brum, Jennifer R -- Ignacio-Espinoza, J Cesar -- Roux, Simon -- Doulcier, Guilhem -- Acinas, Silvia G -- Alberti, Adriana -- Chaffron, Samuel -- Cruaud, Corinne -- de Vargas, Colomban -- Gasol, Josep M -- Gorsky, Gabriel -- Gregory, Ann C -- Guidi, Lionel -- Hingamp, Pascal -- Iudicone, Daniele -- Not, Fabrice -- Ogata, Hiroyuki -- Pesant, Stephane -- Poulos, Bonnie T -- Schwenck, Sarah M -- Speich, Sabrina -- Dimier, Celine -- Kandels-Lewis, Stefanie -- Picheral, Marc -- Searson, Sarah -- Tara Oceans Coordinators -- Bork, Peer -- Bowler, Chris -- Sunagawa, Shinichi -- Wincker, Patrick -- Karsenti, Eric -- Sullivan, Matthew B -- New York, N.Y. -- Science. 2015 May 22;348(6237):1261498. doi: 10.1126/science.1261498.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. ; Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA. ; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. Environmental and Evolutionary Genomics Section, Institut de Biologie de l'Ecole Normale Superieure (IBENS), CNRS, UMR8197, INSERM U1024, 75230 Paris, France. ; Department of Marine Biology and Oceanography, Institute of Marine Sciences (ICM)-CSIC, Pg. Maritim de la Barceloneta 37-49, Barcelona, E08003, Spain. ; Genoscope, Commissariat a l'Energie Atomique (CEA)-Institut de Genomique, 2 rue Gaston Cremieux, 91057 Evry, France. ; Department of Microbiology and Immunology, Rega Institute, KU Leuven, Herestraat 49, 3000 Leuven, Belgium. Center for the Biology of Disease, VIB KU Leuven, Herestraat 49, 3000 Leuven, Belgium. Department of Applied Biological Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium. ; CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Sorbonne Universites, Universite Pierre et Marie Curie, Universite Paris 06, and UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. ; CNRS, UMR 7093, Laboratoire d'oceanographie de Villefranche (LOV), Observatoire Oceanologique, 06230 Villefranche-sur-mer, France. Sorbonne Universites, Uiversite Pierre et Marie Curie, Universite Paris 06, UMR 7093, Laboratoire d'oceanographie de Villefranche (LOV), Observatoire Oceanologique, 06230 Villefranche-sur-mer, France. ; Soil, Water, and Environmental Science, University of Arizona, Tucson, AZ 85721, USA. ; Aix Marseille Universite, CNRS IGS UMR 7256, 13288 Marseille, France. ; Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy. ; Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0001, Japan. ; PANGAEA, Data Publisher for Earth and Environmental Science, University of Bremen, 28359 Bremen, Germany. MARUM, Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany. ; Laboratoire de Physique des Oceans, Institut Universitaire Europeen de la Mer, Universite de Bretagne Occidentale (UBO-IUEM), Place Copernic, 29820 Plouzane, France. ; CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Sorbonne Universites, Universite Pierre et Marie Curie, Universite Paris 06, and UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France. Institut de Biologie de l'Ecole Normale Superieure (IBENS), and INSERM U1024, and CNRS UMR 8197, Paris, 75005, France. ; Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany. Directors' Research, European Molecular Biology Laboratory Meyerhofstrasse 1, 69117 Heidelberg, Germany. ; Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany. Max-Delbruck-Centre for Molecular Medicine, 13092 Berlin, Germany. ; Institut de Biologie de l'Ecole Normale Superieure (IBENS), and INSERM U1024, and CNRS UMR 8197, Paris, 75005, France. ; Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany. ; Genoscope, Commissariat a l'Energie Atomique (CEA)-Institut de Genomique, 2 rue Gaston Cremieux, 91057 Evry, France. CNRS, UMR 8030, CP5706, 91057 Evry, France. Universite d'Evry, UMR 8030, CP5706, 91057 Evry, France. ; Institut de Biologie de l'Ecole Normale Superieure (IBENS), and INSERM U1024, and CNRS UMR 8197, Paris, 75005, France. Directors' Research, European Molecular Biology Laboratory Meyerhofstrasse 1, 69117 Heidelberg, Germany. mbsulli@gmail.com karsenti@embl.de. ; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA. Soil, Water, and Environmental Science, University of Arizona, Tucson, AZ 85721, USA. mbsulli@gmail.com karsenti@embl.de.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25999515" target="_blank"〉PubMed〈/a〉

Description: Laser-driven high-harmonic generation provides the only demonstrated route to generating stable, tabletop attosecond x-ray pulses but has low flux compared to other x-ray technologies. We show that high-harmonic generation can produce higher photon energies and flux by using higher laser intensities than are typical, strongly ionizing the medium and creating plasma that reshapes the driving laser field. We obtain high harmonics capable of supporting attosecond pulses up to photon energies of 600 eV and a photon flux inside the water window (284 to 540 eV) 10 times higher than previous attosecond sources. We demonstrate that operating in this regime is key for attosecond pulse generation in the x-ray range and will become increasingly important as harmonic generation moves to fields that drive even longer wavelengths.

Description: Global biodiversity loss is unprecedented, and threats to existing biodiversity are growing. Given pervasive global change, a major challenge facing resource managers is a lack of scalable tools to rapidly and consistently measure Earth's biodiversity. Environmental genomic tools provide some hope in the face of this crisis, and DNA metabarcoding, in particular, is a powerful approach for biodiversity assessment at large spatial scales. However, metabarcoding studies are variable in their taxonomic, temporal, or spatial scope, investigating individual species, specific taxonomic groups, or targeted communities at local or regional scales. With the advent of modern, ultra-high throughput sequencing platforms, conducting deep sequencing metabarcoding surveys with multiple DNA markers will enhance the breadth of biodiversity coverage, enabling comprehensive, rapid bioassessment of all the organisms in a sample. Here, we report on a systematic literature review of 1,563 articles published about DNA metabarcoding and summarize how this approach is rapidly revolutionizing global bioassessment efforts. Specifically, we quantify the stakeholders using DNA metabarcoding, the dominant applications of this technology, and the taxonomic groups assessed in these studies. We show that while DNA metabarcoding has reached global coverage, few studies deliver on its promise of near-comprehensive biodiversity assessment. We then outline how DNA metabarcoding can help us move toward real-time, global bioassessment, illustrating how different stakeholders could benefit from DNA metabarcoding. Next, we address barriers to widespread adoption of DNA metabarcoding, highlighting the need for standardized sampling protocols, experts and computational resources to handle the deluge of genomic data, and standardized, open-source bioinformatic pipelines. Finally, we explore how technological and scientific advances will realize the promise of total biodiversity assessment in a sample—from microbes to mammals—and unlock the rich information genomics exposes, opening new possibilities for merging whole-system DNA metabarcoding with (1) abundance and biomass quantification, (2) advanced modeling, such as species occupancy models, to improve species detection, (3) population genetics, (4) phylogenetics, and (5) food web and functional gene analysis. While many challenges need to be addressed to facilitate widespread adoption of environmental genomic approaches, concurrent scientific and technological advances will usher in methods to supplement existing bioassessment tools reliant on morphological and abiotic data. This expanded toolbox will help ensure that the best tool is used for the job and enable exciting integrative techniques that capitalize on multiple tools. Collectively, these new approaches will aid in addressing the global biodiversity crisis we now face.

Description: Background: Genetic recombination is a driving force in genome evolution. Among viruses it has a dual role. For genomes with higher fitness, it maintains genome integrity in the face of high mutation rates. Conversely, for genomes with lower fitness, it provides immediate access to sequence space that cannot be reached by mutation alone. Understanding how recombination impacts the cohesion and dissolution of individual whole genomes within viral sequence space is poorly understood across double-stranded DNA bacteriophages (a.k.a phages) due to the challenges of obtaining appropriately scaled genomic datasets. Results: Here we explore the role of recombination in both maintaining and differentiating whole genomes of 142 wild double-stranded DNA marine cyanophages. Phylogenomic analysis across the 51 core genes revealed ten lineages, six of which were well represented. These phylogenomic lineages represent discrete genotypic populations based on comparisons of intra- and inter- lineage shared gene content, genome-wide average nucleotide identity, as well as detected gaps in the distribution of pairwise differences between genomes. McDonald-Kreitman selection tests identified putative niche-differentiating genes under positive selection that differed across the six well-represented genotypic populations and that may have driven initial divergence. Concurrent with patterns of recombination of discrete populations, recombination analyses of both genic and intergenic regions largely revealed decreased genetic exchange across individual genomes between relative to within populations. Conclusions: These findings suggest that discrete double-stranded DNA marine cyanophage populations occur in nature and are maintained by patterns of recombination akin to those observed in bacteria, archaea and in sexual eukaryotes. © 2016 The Author(s).