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https://www.readbyqxmd.com/read/28605718/diversity-classification-and-evolution-of-crispr-cas-systems
#1
REVIEW
Eugene V Koonin, Kira S Makarova, Feng Zhang
The bacterial and archaeal CRISPR-Cas systems of adaptive immunity show remarkable diversity of protein composition, effector complex structure, genome locus architecture and mechanisms of adaptation, pre-CRISPR (cr)RNA processing and interference. The CRISPR-Cas systems belong to two classes, with multi-subunit effector complexes in Class 1 and single-protein effector modules in Class 2. Concerted genomic and experimental efforts on comprehensive characterization of Class 2 CRISPR-Cas systems led to the identification of two new types and several subtypes...
June 9, 2017: Current Opinion in Microbiology
https://www.readbyqxmd.com/read/28572664/mapping-refrigerant-gases-in-the-new-york-city-skyline
#2
Masoud Ghandehari, Milad Aghamohamadnia, Gregory Dobler, Andreas Karpf, Kerry Buckland, Jun Qian, Steven Koonin
Cities are now home to more than 50% of the world's population and emit large quantities of pollutants from sources such as fossil fuel combustion and the leakage of refrigerants. We demonstrate the utility of persistent synoptic longwave hyperspectral imaging to study the ongoing leakage of refrigerant gases in New York City, compounds that either deplete the stratosphere ozone or have significant global warming potential. In contrast to current monitoring programs that are based on country-level reporting or aggregate measures of emissions, we present the identification of gaseous plumes with high spatial and temporal granularity in real-time over the skyline of Manhattan...
June 1, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28555626/discovery-of-extremely-halophilic-methyl-reducing-euryarchaea-provides-insights-into-the-evolutionary-origin-of-methanogenesis
#3
Dimitry Y Sorokin, Kira S Makarova, Ben Abbas, Manuel Ferrer, Peter N Golyshin, Erwin A Galinski, Sergio Ciordia, María Carmen Mena, Alexander Y Merkel, Yuri I Wolf, Mark C M van Loosdrecht, Eugene V Koonin
Methanogenic archaea are major players in the global carbon cycle and in the biotechnology of anaerobic digestion. The phylum Euryarchaeota includes diverse groups of methanogens that are interspersed with non-methanogenic lineages. So far, methanogens inhabiting hypersaline environments have been identified only within the order Methanosarcinales. We report the discovery of a deep phylogenetic lineage of extremophilic methanogens in hypersaline lakes and present analysis of two nearly complete genomes from this group...
May 30, 2017: Nature Microbiology
https://www.readbyqxmd.com/read/28545555/the-complex-domain-architecture-of-samd9-family-proteins-predicted-stand-like-ntpases-suggests-new-links-to-inflammation-and-apoptosis
#4
Sergei L Mekhedov, Kira S Makarova, Eugene V Koonin
We report a comprehensive computational dissection of the domain architecture of the SAMD9 family proteins that are involved in antivirus and antitumor response in humans. We show that the SAMD9 protein family is represented in most animals and also, unexpectedly, in bacteria, in particular actinomycetes. From the N to C terminus, the core SAMD9 family architecture includes DNA/RNA-binding AlbA domain, a variant Sir2-like domain, a STAND-like P-loop NTPase, an array of TPR repeats and an OB-fold domain with predicted RNA-binding properties...
May 25, 2017: Biology Direct
https://www.readbyqxmd.com/read/28545255/frozen-accident-pushing-50-stereochemistry-expansion-and-chance-in-the-evolution-of-the-genetic-code
#5
Eugene V Koonin
Nearly 50 years ago, Francis Crick propounded the frozen accident scenario for the evolution of the genetic code along with the hypothesis that the early translation system consisted primarily of RNA. Under the frozen accident perspective, the code is universal among modern life forms because any change in codon assignment would be highly deleterious. The frozen accident can be considered the default theory of code evolution because it does not imply any specific interactions between amino acids and the cognate codons or anticodons, or any particular properties of the code...
May 23, 2017: Life
https://www.readbyqxmd.com/read/28544876/principles-of-systems-biology-no-17
#6
(no author information available yet)
This month: understanding spatial arrangements (Süel/Laue/Schweisguth/de Lorenzo), a giant virus sheds light on evolution (Koonin), synthetic systems (Comtet, Wang, Pósfai), and omics tools (Siuzdak, Kim).
May 24, 2017: Cell Systems
https://www.readbyqxmd.com/read/28514948/demystification-of-animal-symmetry-symmetry-is-a-response-to-mechanical-forces
#7
Gábor Holló
ᅟ: Symmetry is an eye-catching feature of animal body plans, yet its causes are not well enough understood. The evolution of animal form is mainly due to changes in gene regulatory networks (GRNs). Based on theoretical considerations regarding fundamental GRN properties, it has recently been proposed that the animal genome, on large time scales, should be regarded as a system which can construct both the main symmetries - radial and bilateral - simultaneously; and that the expression of any of these depends on functional constraints...
May 17, 2017: Biology Direct
https://www.readbyqxmd.com/read/28472712/casposons-mobile-genetic-elements-that-gave-rise-to-the-crispr-cas-adaptation-machinery
#8
REVIEW
Mart Krupovic, Pierre Béguin, Eugene V Koonin
A casposon, a member of a distinct superfamily of archaeal and bacterial self-synthesizing transposons that employ a recombinase (casposase) homologous to the Cas1 endonuclease, appears to have given rise to the adaptation module of CRISPR-Cas systems as well as the CRISPR repeats themselves. Comparison of the mechanistic features of the reactions catalyzed by the casposase and the Cas1-Cas2 heterohexamer, the CRISPR integrase, reveals close similarity but also important differences that explain the requirement of Cas2 for integration of short DNA fragments, the CRISPR spacers...
May 1, 2017: Current Opinion in Microbiology
https://www.readbyqxmd.com/read/28457865/novel-abundant-oceanic-viruses-of-uncultured-marine-group-ii-euryarchaeota
#9
Alon Philosof, Natalya Yutin, José Flores-Uribe, Itai Sharon, Eugene V Koonin, Oded Béjà
Marine group II Euryarchaeota (MG-II) are among the most abundant microbes in oceanic surface waters [1-4]. So far, however, representatives of MG-II have not been cultivated, and no viruses infecting these organisms have been described. Here, we present complete genomes for three distinct groups of viruses assembled from metagenomic sequence datasets highly enriched for MG-II. These novel viruses, which we denote magroviruses, possess double-stranded DNA genomes of 65 to 100 kilobases in size that encode a structural module characteristic of head-tailed viruses and, unusually for archaeal and bacterial viruses, a nearly complete replication apparatus of apparent archaeal origin...
May 8, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28451057/a-network-perspective-on-the-virus-world
#10
COMMENT
Jaime Iranzo, Mart Krupovic, Eugene V Koonin
Viral evolution is characterized by high rates of horizontal gene transfer and fast sequence divergence. Furthermore, there are no universal genes shared by all viruses. As a result, distant relationships among viruses are better represented by a network than by a tree. Here we discuss 3 network representations of the virus world with decreasing levels of complexity, from a multilayer network that integrates sequence conservation and patterns of gene sharing to a classic genome similarity network. As new tools for network analysis are developed, we expect that novel insights into virus evolution will result from the study of more complex representations of the virus world...
2017: Communicative & Integrative Biology
https://www.readbyqxmd.com/read/28408723/nucleic-acid-detection-with-crispr-cas13a-c2c2
#11
Jonathan S Gootenberg, Omar O Abudayyeh, Jeong Wook Lee, Patrick Essletzbichler, Aaron J Dy, Julia Joung, Vanessa Verdine, Nina Donghia, Nichole M Daringer, Catherine A Freije, Cameron Myhrvold, Roby P Bhattacharyya, Jonathan Livny, Aviv Regev, Eugene V Koonin, Deborah T Hung, Pardis C Sabeti, James J Collins, Feng Zhang
Rapid, inexpensive, and sensitive nucleic acid detection may aid point-of-care pathogen detection, genotyping, and disease monitoring. The RNA-guided, RNA-targeting clustered regularly interspaced short palindromic repeats (CRISPR) effector Cas13a (previously known as C2c2) exhibits a "collateral effect" of promiscuous ribonuclease activity upon target recognition. We combine the collateral effect of Cas13a with isothermal amplification to establish a CRISPR-based diagnostic (CRISPR-Dx), providing rapid DNA or RNA detection with attomolar sensitivity and single-base mismatch specificity...
April 28, 2017: Science
https://www.readbyqxmd.com/read/28386012/giant-viruses-with-an-expanded-complement-of-translation-system-components
#12
Frederik Schulz, Natalya Yutin, Natalia N Ivanova, Davi R Ortega, Tae Kwon Lee, Julia Vierheilig, Holger Daims, Matthias Horn, Michael Wagner, Grant J Jensen, Nikos C Kyrpides, Eugene V Koonin, Tanja Woyke
The discovery of giant viruses blurred the sharp division between viruses and cellular life. Giant virus genomes encode proteins considered as signatures of cellular organisms, particularly translation system components, prompting hypotheses that these viruses derived from a fourth domain of cellular life. Here we report the discovery of a group of giant viruses (Klosneuviruses) in metagenomic data. Compared with other giant viruses, the Klosneuviruses encode an expanded translation machinery, including aminoacyl transfer RNA synthetases with specificities for all 20 amino acids...
April 7, 2017: Science
https://www.readbyqxmd.com/read/28376755/reconstruction-of-the-evolution-of-microbial-defense-systems
#13
Pere Puigbò, Kira S Makarova, David M Kristensen, Yuri I Wolf, Eugene V Koonin
BACKGROUND: Evolution of bacterial and archaeal genomes is a highly dynamic process that involves intensive loss of genes as well as gene gain via horizontal transfer, with a lesser contribution from gene duplication. The rates of these processes can be estimated by comparing genomes that are linked by an evolutionary tree. These estimated rates of genome dynamics events substantially differ for different functional classes of genes. The genes involved in defense against viruses and other invading DNA are among those that are gained and lost at the highest rates...
April 4, 2017: BMC Evolutionary Biology
https://www.readbyqxmd.com/read/28356531/homologous-capsid-proteins-testify-to-the-common-ancestry-of-retroviruses-caulimoviruses-pseudoviruses-and-metaviruses
#14
Mart Krupovic, Eugene V Koonin
Reverse-transcribing viruses are classified into 5 different families, Retroviridae, Metaviridae, Pseudoviridae, Caulimoviridae and Hepadnaviridae (1).….
March 29, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28265094/multiple-origins-of-viral-capsid-proteins-from-cellular-ancestors
#15
Mart Krupovic, Eugene V Koonin
Viruses are the most abundant biological entities on earth and show remarkable diversity of genome sequences, replication and expression strategies, and virion structures. Evolutionary genomics of viruses revealed many unexpected connections but the general scenario(s) for the evolution of the virosphere remains a matter of intense debate among proponents of the cellular regression, escaped genes, and primordial virus world hypotheses. A comprehensive sequence and structure analysis of major virion proteins indicates that they evolved on about 20 independent occasions, and in some of these cases likely ancestors are identifiable among the proteins of cellular organisms...
March 21, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28245845/adaptive-multiscapes-an-up-to-date-metaphor-to-visualize-molecular-adaptation
#16
EDITORIAL
Pablo Catalán, Clemente F Arias, Jose A Cuesta, Susanna Manrubia
BACKGROUND: Wright's metaphor of the fitness landscape has shaped and conditioned our view of the adaptation of populations for almost a century. Since its inception, and including criticism raised by Wright himself, the concept has been surrounded by controversy. Among others, the debate stems from the intrinsic difficulty to capture important features of the space of genotypes, such as its high dimensionality or the existence of abundant ridges, in a visually appealing two-dimensional picture...
February 28, 2017: Biology Direct
https://www.readbyqxmd.com/read/28187792/evolution-of-rna-and-dna-guided-antivirus-defense-systems-in-prokaryotes-and-eukaryotes-common-ancestry-vs-convergence
#17
REVIEW
Eugene V Koonin
Complementarity between nucleic acid molecules is central to biological information transfer processes. Apart from the basal processes of replication, transcription and translation, complementarity is also employed by multiple defense and regulatory systems. All cellular life forms possess defense systems against viruses and mobile genetic elements, and in most of them some of the defense mechanisms involve small guide RNAs or DNAs that recognize parasite genomes and trigger their inactivation. The nucleic acid-guided defense systems include prokaryotic Argonaute (pAgo)-centered innate immunity and CRISPR-Cas adaptive immunity as well as diverse branches of RNA interference (RNAi) in eukaryotes...
February 10, 2017: Biology Direct
https://www.readbyqxmd.com/read/28134265/consensus-statement-virus-taxonomy-in-the-age-of-metagenomics
#18
Peter Simmonds, Mike J Adams, Mária Benkő, Mya Breitbart, J Rodney Brister, Eric B Carstens, Andrew J Davison, Eric Delwart, Alexander E Gorbalenya, Balázs Harrach, Roger Hull, Andrew M Q King, Eugene V Koonin, Mart Krupovic, Jens H Kuhn, Elliot J Lefkowitz, Max L Nibert, Richard Orton, Marilyn J Roossinck, Sead Sabanadzovic, Matthew B Sullivan, Curtis A Suttle, Robert B Tesh, René A van der Vlugt, Arvind Varsani, F Murilo Zerbini
The number and diversity of viral sequences that are identified in metagenomic data far exceeds that of experimentally characterized virus isolates. In a recent workshop, a panel of experts discussed the proposal that, with appropriate quality control, viruses that are known only from metagenomic data can, and should be, incorporated into the official classification scheme of the International Committee on Taxonomy of Viruses (ICTV). Although a taxonomy that is based on metagenomic sequence data alone represents a substantial departure from the traditional reliance on phenotypic properties, the development of a robust framework for sequence-based virus taxonomy is indispensable for the comprehensive characterization of the global virome...
March 2017: Nature Reviews. Microbiology
https://www.readbyqxmd.com/read/28115717/profile-of-eugene-v-koonin
#19
Paul Gabrielsen
No abstract text is available yet for this article.
January 31, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28111461/diversity-and-evolution-of-class-2-crispr-cas-systems
#20
Sergey Shmakov, Aaron Smargon, David Scott, David Cox, Neena Pyzocha, Winston Yan, Omar O Abudayyeh, Jonathan S Gootenberg, Kira S Makarova, Yuri I Wolf, Konstantin Severinov, Feng Zhang, Eugene V Koonin
Class 2 CRISPR-Cas systems are characterized by effector modules that consist of a single multidomain protein, such as Cas9 or Cpf1. We designed a computational pipeline for the discovery of novel class 2 variants and used it to identify six new CRISPR-Cas subtypes. The diverse properties of these new systems provide potential for the development of versatile tools for genome editing and regulation. In this Analysis article, we present a comprehensive census of class 2 types and class 2 subtypes in complete and draft bacterial and archaeal genomes, outline evolutionary scenarios for the independent origin of different class 2 CRISPR-Cas systems from mobile genetic elements, and propose an amended classification and nomenclature of CRISPR-Cas...
March 2017: Nature Reviews. Microbiology
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