1
|
Zhao H, Meng L, Hikida H, Ogata H. Eukaryotic genomic data uncover an extensive host range of mirusviruses. Curr Biol 2024; 34:2633-2643.e3. [PMID: 38806056 DOI: 10.1016/j.cub.2024.04.085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 04/10/2024] [Accepted: 04/30/2024] [Indexed: 05/30/2024]
Abstract
A recent marine metagenomic study has revealed the existence of a novel group of viruses designated mirusviruses, which are proposed to form an evolutionary link between two realms of double-stranded DNA viruses, Varidnaviria and Duplodnaviria. Metagenomic data suggest that mirusviruses infect microeukaryotes in the photic layer of the ocean, but their host range remains largely unknown. In this study, we investigated the presence of mirusvirus marker genes in 1,901 publicly available eukaryotic genome assemblies, mainly derived from unicellular eukaryotes, to identify potential hosts of mirusviruses. Mirusvirus marker sequences were identified in 915 assemblies spanning 227 genera across eight supergroups of eukaryotes. The habitats of the putative mirusvirus hosts included not only marine but also other diverse environments. Among the major capsid protein (MCP) signals in the genome assemblies, we identified 85 sequences that showed high sequence and structural similarities to reference mirusvirus MCPs. A phylogenetic analysis of these sequences revealed their distant evolutionary relationships with the seven previously reported mirusvirus clades. Most of the scaffolds with these MCP sequences encoded multiple mirusvirus homologs, suggesting that mirusviral infection contributes to the alteration of the host genome. We also identified three circular mirusviral genomes within the genomic data of the oil-producing thraustochytrid Schizochytrium sp. and the endolithic green alga Ostreobium quekettii. Overall, mirusviruses probably infect a wide spectrum of eukaryotes and are more diverse than previously reported.
Collapse
Affiliation(s)
- Hongda Zhao
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Lingjie Meng
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Hiroyuki Hikida
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Hiroyuki Ogata
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
| |
Collapse
|
2
|
Zhao H, Meng L, Hikida H, Ogata H. Eukaryotic genomic data uncover an extensive host range of mirusviruses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.18.576163. [PMID: 38293090 PMCID: PMC10827195 DOI: 10.1101/2024.01.18.576163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
A recent marine metagenomic study has revealed the existence of a novel group of viruses designated mirusviruses, which are proposed to form an evolutionary link between two realms of double-stranded DNA viruses, Varidnaviria and Duplodnaviria. Metagenomic data suggest that mirusviruses infect microeukaryotes in the photic layer of the ocean, but their host range remains largely unknown. In this study, we investigated the presence of mirusvirus marker genes in publicly available 1,901 eukaryotic genome assemblies, mainly derived from unicellular eukaryotes, to identify potential hosts of mirusviruses. Mirusvirus marker sequences were identified in 1,348 assemblies spanning 284 genera across eight supergroups of eukaryotes. The habitats of the putative mirusvirus hosts included not only marine but also other diverse environments. Among the major capsid protein (MCP) signals in the genome assemblies, we identified 85 sequences that showed high sequence and structural similarities to reference mirusvirus MCPs. A phylogenetic analysis of these sequences revealed their distant evolutionary relationships with the seven previously reported mirusvirus clades. Most of the scaffolds with these MCP sequences encoded multiple mirusvirus homologs, underscoring the impact of mirusviral infection on the evolution of the host genome. We also identified three circular mirusviral genomes within the genomic data of the oil producing thraustochytrid Schizochytrium sp. and the endolithic green alga Ostreobium quekettii. Overall, mirusviruses probably infect a wide spectrum of eukaryotes and are more diverse than previously reported.
Collapse
Affiliation(s)
- Hongda Zhao
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan
| | - Lingjie Meng
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan
| | - Hiroyuki Hikida
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan
| | - Hiroyuki Ogata
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan
| |
Collapse
|
3
|
Kuiper BP, Schöntag AMC, Oksanen HM, Daum B, Quax TEF. Archaeal virus entry and egress. MICROLIFE 2024; 5:uqad048. [PMID: 38234448 PMCID: PMC10791045 DOI: 10.1093/femsml/uqad048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 11/08/2023] [Accepted: 01/02/2024] [Indexed: 01/19/2024]
Abstract
Archaeal viruses display a high degree of structural and genomic diversity. Few details are known about the mechanisms by which these viruses enter and exit their host cells. Research on archaeal viruses has lately made significant progress due to advances in genetic tools and imaging techniques, such as cryo-electron tomography (cryo-ET). In recent years, a steady output of newly identified archaeal viral receptors and egress mechanisms has offered the first insight into how archaeal viruses interact with the archaeal cell envelope. As more details about archaeal viral entry and egress are unravelled, patterns are starting to emerge. This helps to better understand the interactions between viruses and the archaeal cell envelope and how these compare to infection strategies of viruses in other domains of life. Here, we provide an overview of recent developments in the field of archaeal viral entry and egress, shedding light onto the most elusive part of the virosphere.
Collapse
Affiliation(s)
- Bastiaan P Kuiper
- Biology of Archaea and Viruses, Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, Faculty for Science and Engineering, University of Groningen, 7th floor, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Anna M C Schöntag
- Biology of Archaea and Viruses, Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, Faculty for Science and Engineering, University of Groningen, 7th floor, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Hanna M Oksanen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 9, FI-00014 Helsinki, Finland
| | - Bertram Daum
- Living Systems Institute, Faculty of Health and Life Sciences, University of Exeter, Exeter EX4 4QD, United Kingdom
| | - Tessa E F Quax
- Biology of Archaea and Viruses, Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, Faculty for Science and Engineering, University of Groningen, 7th floor, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| |
Collapse
|
4
|
Alarcón-Schumacher T, Lücking D, Erdmann S. Revisiting evolutionary trajectories and the organization of the Pleolipoviridae family. PLoS Genet 2023; 19:e1010998. [PMID: 37831715 PMCID: PMC10599561 DOI: 10.1371/journal.pgen.1010998] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 10/25/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
Archaeal pleomorphic viruses belonging to the Pleolipoviridae family represent an enigmatic group as they exhibit unique genomic features and are thought to have evolved through recombination with different archaeal plasmids. However, most of our understanding of the diversity and evolutionary trajectories of this clade comes from a handful of isolated representatives. Here we present 164 new genomes of pleolipoviruses obtained from metagenomic data of Australian hypersaline lakes and publicly available metagenomic data. We perform a comprehensive analysis on the diversity and evolutionary relationships of the newly discovered viruses and previously described pleolipoviruses. We propose to classify the viruses into five genera within the Pleolipoviridae family, with one new genus represented only by virus genomes retrieved in this study. Our data support the current hypothesis that pleolipoviruses reshaped their genomes through recombining with multiple different groups of plasmids, which is reflected in the diversity of their predicted replication strategies. We show that the proposed genus Epsilonpleolipovirus has evolutionary ties to pRN1-like plasmids from Sulfolobus, suggesting that this group could be infecting other archaeal phyla. Interestingly, we observed that the genome size of pleolipoviruses is correlated to the presence or absence of an integrase. Analyses of the host range revealed that all but one virus exhibit an extremely narrow range, and we show that the predicted tertiary structure of the spike protein is strongly associated with the host family, suggesting a specific adaptation to the host S-layer glycoprotein organization.
Collapse
Affiliation(s)
| | - Dominik Lücking
- Max-Planck-Institute for Marine Microbiology, Bremen, Germany
| | - Susanne Erdmann
- Max-Planck-Institute for Marine Microbiology, Bremen, Germany
| |
Collapse
|
5
|
Mercier C, Thies D, Zhong L, Raftery MJ, Erdmann S. Characterization of an archaeal virus-host system reveals massive genomic rearrangements in a laboratory strain. Front Microbiol 2023; 14:1274068. [PMID: 37789858 PMCID: PMC10544981 DOI: 10.3389/fmicb.2023.1274068] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 09/04/2023] [Indexed: 10/05/2023] Open
Abstract
Halophilic archaea (haloarchaea) are known to exhibit multiple chromosomes, with one main chromosome and one or several smaller secondary chromosomes or megaplasmids. Halorubrum lacusprofundi, a model organism for studying cold adaptation, exhibits one secondary chromosome and one megaplasmid that include a large arsenal of virus defense mechanisms. We isolated a virus (Halorubrum tailed virus DL1, HRTV-DL1) infecting Hrr. lacusprofundi, and present an in-depth characterization of the virus and its interactions with Hrr. lacusprofundi. While studying virus-host interactions between Hrr. lacusprofundi and HRTV-DL1, we uncover that the strain in use (ACAM34_UNSW) lost the entire megaplasmid and about 38% of the secondary chromosome. The loss included the majority of virus defense mechanisms, making the strain sensitive to HRTV-DL1 infection, while the type strain (ACAM34_DSMZ) appears to prevent virus replication. Comparing infection of the type strain ACAM34_DSMZ with infection of the laboratory derived strain ACAM34_UNSW allowed us to identify host responses to virus infection that were only activated in ACAM34_UNSW upon the loss of virus defense mechanisms. We identify one of two S-layer proteins as primary receptor for HRTV-DL1 and conclude that the presence of two different S-layer proteins in one strain provides a strong advantage in the arms race with viruses. Additionally, we identify archaeal homologs to eukaryotic proteins potentially being involved in the defense against virus infection.
Collapse
Affiliation(s)
- Coraline Mercier
- Max Planck Institute for Marine Microbiology, Archaeal Virology, Bremen, Germany
| | - Daniela Thies
- Max Planck Institute for Marine Microbiology, Archaeal Virology, Bremen, Germany
| | - Ling Zhong
- Bioanalytical Mass Spectrometry Facility, The University of New South Wales, Sydney, NSW, Australia
| | - Mark J. Raftery
- Bioanalytical Mass Spectrometry Facility, The University of New South Wales, Sydney, NSW, Australia
| | - Susanne Erdmann
- Max Planck Institute for Marine Microbiology, Archaeal Virology, Bremen, Germany
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| |
Collapse
|
6
|
Diao K, Li G, Sun X, Yi H, Zhang S, Xiao W. Genomic Characterization of a Halovirus Representing a Novel Siphoviral Cluster. Viruses 2023; 15:1392. [PMID: 37376691 DOI: 10.3390/v15061392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 06/01/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
Salt mines are a special type of hypersaline environment. Current research mainly focuses on prokaryotes, and the understanding of viruses in salt mines remains limited. Understanding viruses in hypersaline environments is of great significance for revealing the formation and maintenance of microbial communities, energy flow and element cycling, and host ecological functions. A phage infecting Halomonas titanicae was isolated from Yipinglang Salt Mine in China, designated Halomonas titanicae phage vB_HtiS_YPHTV-1 (YPHTV-1). Transmission electron microscopy revealed that YPHTV-1 had an icosahedral head with a diameter of 49.12 ± 0.15 nm (n = 5) and a long noncontractile tail with a length of 141.7 ± 0.58 nm (n = 5), indicating that it was a siphovirus. The one-step growth curve showed that the burst size of YPHTV-1 was 69 plaque forming units (PFUs) cell-1. The genome of YPHTV-1 was 37,980 bp with a GC content of 36.2%. The phylogenetic analysis of the six conserved proteins indicated that YPHTV-1 formed a cluster with Bacillus phages and was separated from phages infecting Halomonas. The average nucleotide identity (ANI), phylogenetic, and network analyses indicated that the phage YPHTV-1 represented a new genus under Caudoviricetes. In total, 57 open reading frames (ORFs) were predicted in the YPHTV-1 genome, 30 of which could be annotated in the database. Notably, several auxiliary metabolic genes were encoded by YPHTV-1, such as ImmA/IrrE family metalloendopeptidase, mannose-binding lectin (MBL) folding metallohydrolase, M15 family of metal peptidases, MazG-like family protein, O antigen ligase, and acyltransferase. These genes potentially enabled the host bacterium to resist ionizing radiation, ultraviolet light (UV), mitomycin C, β-lactam antibiotic, high osmotic pressure, and nutritional deficiencies. These findings highlight the role of haloviruses in the life cycle of halobacteria.
Collapse
Affiliation(s)
- Kaixin Diao
- Yunnan Institute of Microbiology, Yunnan International Joint Laboratory of Virology & Immunology, Yunnan University, Kunming 650500, China
| | - Guohui Li
- Yunnan Institute of Microbiology, Yunnan International Joint Laboratory of Virology & Immunology, Yunnan University, Kunming 650500, China
| | - Xueqin Sun
- Yunnan Institute of Microbiology, Yunnan International Joint Laboratory of Virology & Immunology, Yunnan University, Kunming 650500, China
| | - Hao Yi
- Yunnan Institute of Microbiology, Yunnan International Joint Laboratory of Virology & Immunology, Yunnan University, Kunming 650500, China
| | - Shiying Zhang
- Yunnan Soil Fertilization and Pollution Remediation Engineering Research Center, Yunnan Agricultural University, Kunming 650201, China
| | - Wei Xiao
- Yunnan Institute of Microbiology, Yunnan International Joint Laboratory of Virology & Immunology, Yunnan University, Kunming 650500, China
| |
Collapse
|
7
|
Liu Y, Demina TA, Roux S, Aiewsakun P, Kazlauskas D, Simmonds P, Prangishvili D, Oksanen HM, Krupovic M. Diversity, taxonomy, and evolution of archaeal viruses of the class Caudoviricetes. PLoS Biol 2021; 19:e3001442. [PMID: 34752450 PMCID: PMC8651126 DOI: 10.1371/journal.pbio.3001442] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/07/2021] [Accepted: 10/17/2021] [Indexed: 11/19/2022] Open
Abstract
The archaeal tailed viruses (arTV), evolutionarily related to tailed double-stranded DNA (dsDNA) bacteriophages of the class Caudoviricetes, represent the most common isolates infecting halophilic archaea. Only a handful of these viruses have been genomically characterized, limiting our appreciation of their ecological impacts and evolution. Here, we present 37 new genomes of haloarchaeal tailed virus isolates, more than doubling the current number of sequenced arTVs. Analysis of all 63 available complete genomes of arTVs, which we propose to classify into 14 new families and 3 orders, suggests ancient divergence of archaeal and bacterial tailed viruses and points to an extensive sharing of genes involved in DNA metabolism and counterdefense mechanisms, illuminating common strategies of virus-host interactions with tailed bacteriophages. Coupling of the comparative genomics with the host range analysis on a broad panel of haloarchaeal species uncovered 4 distinct groups of viral tail fiber adhesins controlling the host range expansion. The survey of metagenomes using viral hallmark genes suggests that the global architecture of the arTV community is shaped through recurrent transfers between different biomes, including hypersaline, marine, and anoxic environments.
Collapse
Affiliation(s)
- Ying Liu
- Institut Pasteur, Université de Paris, Archaeal Virology Unit, Paris, France
| | - Tatiana A. Demina
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Simon Roux
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Pakorn Aiewsakun
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand
- Pornchai Matangkasombut Center for Microbial Genomics, Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Darius Kazlauskas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Peter Simmonds
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - David Prangishvili
- Institut Pasteur, Université de Paris, Archaeal Virology Unit, Paris, France
- Ivane Javakhishvili Tbilisi State University, Tbilisi, Georgia
| | - Hanna M. Oksanen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Mart Krupovic
- Institut Pasteur, Université de Paris, Archaeal Virology Unit, Paris, France
| |
Collapse
|
8
|
The Novel Halovirus Hardycor1, and the Presence of Active (Induced) Proviruses in Four Haloarchaea. Genes (Basel) 2021; 12:genes12020149. [PMID: 33498646 PMCID: PMC7911831 DOI: 10.3390/genes12020149] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 12/15/2022] Open
Abstract
The virus Hardycor1 was isolated in 1998 and infects the haloarchaeon Halorubrum coriense. DNA from a frozen stock (HC1) was sequenced and the viral genome found to be 45,142 bp of dsDNA, probably having redundant, circularly permuted termini. The genome showed little similarity (BLASTn) to known viruses. Only twenty-two of the 53 (41%) predicted proteins were significantly similar to sequences in the NCBI nr protein database (E-value ≤ 10-15). Six caudovirus-like proteins were encoded, including large subunit terminase (TerL), major capsid protein (Mcp) and tape measure protein (Tmp). Hardycor1 was predicted to be a siphovirus (VIRFAM). No close relationship to other viruses was found using phylogenetic tree reconstructions based on TerL and Mcp. Unexpectedly, the sequenced virus stock HC1 also revealed two induced proviruses of the host: a siphovirus (Humcor1) and a pleolipovirus (Humcor2). A re-examination of other similarly sequenced, archival virus stocks revealed induced proviruses of Haloferax volcanii, Haloferax gibbonsii and Haloarcula hispanica, three of which were pleolipoviruses. One provirus (Halfvol2) of Hfx. volcanii showed little similarity (BLASTn) to known viruses and probably represents a novel virus group. The attP sequences of many pleolipoproviruses were found to be embedded in a newly detected coding sequence, split in the provirus state, that spans between genes for integrase and a downstream CxxC-motif protein. This gene might play an important role in regulation of the temperate state.
Collapse
|
9
|
Wang J, Liu Y, Liu Y, Du K, Xu S, Wang Y, Krupovic M, Chen X. A novel family of tyrosine integrases encoded by the temperate pleolipovirus SNJ2. Nucleic Acids Res 2019; 46:2521-2536. [PMID: 29361162 PMCID: PMC5861418 DOI: 10.1093/nar/gky005] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 01/08/2018] [Indexed: 01/19/2023] Open
Abstract
Genomes of halophilic archaea typically contain multiple loci of integrated mobile genetic elements (MGEs). Despite the abundance of these elements, however, mechanisms underlying their site-specific integration and excision have not been investigated. Here, we identified and characterized a novel recombination system encoded by the temperate pleolipovirus SNJ2, which infects haloarchaeon Natrinema sp. J7-1. SNJ2 genome is inserted into the tRNAMet gene and flanked by 14 bp direct repeats corresponding to attachment core sites. We showed that SNJ2 encodes an integrase (IntSNJ2) that excises the proviral genome from its host cell chromosome, but requires two small accessory proteins, Orf2 and Orf3, for integration. These proteins were co-transcribed with IntSNJ2 to form an operon. Homology searches showed that IntSNJ2-type integrases are widespread in haloarchaeal genomes and are associated with various integrated MGEs. Importantly, we confirmed that SNJ2-like recombination systems are encoded by haloarchaea from three different genera and are critical for integration and excision. Finally, phylogenetic analysis suggested that IntSNJ2-type recombinases belong to a novel family of archaeal integrases distinct from previously characterized recombinases, including those from the archaeal SSV- and pNOB8-type families.
Collapse
Affiliation(s)
- Jiao Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yingchun Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Ying Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.,Unit of Molecular Biology of the Gene in Extremophiles, Department of Microbiology, Institut Pasteur, Paris 75015, France
| | - Kaixin Du
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Shuqi Xu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yuchen Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Mart Krupovic
- Unit of Molecular Biology of the Gene in Extremophiles, Department of Microbiology, Institut Pasteur, Paris 75015, France
| | - Xiangdong Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| |
Collapse
|
10
|
Martin‐Cuadrado A, Senel E, Martínez‐García M, Cifuentes A, Santos F, Almansa C, Moreno‐Paz M, Blanco Y, García‐Villadangos M, Cura MÁG, Sanz‐Montero ME, Rodríguez‐Aranda JP, Rosselló‐Móra R, Antón J, Parro V. Prokaryotic and viral community of the sulfate‐rich crust from Peñahueca ephemeral lake, an astrobiology analogue. Environ Microbiol 2019; 21:3577-3600. [DOI: 10.1111/1462-2920.14680] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/09/2019] [Accepted: 05/11/2019] [Indexed: 11/29/2022]
Affiliation(s)
| | - Ece Senel
- Department of Physiology, Genetics and MicrobiologyUniversity of Alicante Alicante Spain
- Department of BiologyGraduate School of Sciences, Eskisehir Technical University Yunusemre Campus, Eskisehir 26470 Turkey
| | - Manuel Martínez‐García
- Department of Physiology, Genetics and MicrobiologyUniversity of Alicante Alicante Spain
| | - Ana Cifuentes
- Department of Ecology and Marine Resources, Marine Microbiology GroupMediterranean Institute for Advanced Studies (IMEDEA, CSIC‐UIB) Esporles Spain
| | - Fernando Santos
- Department of Physiology, Genetics and MicrobiologyUniversity of Alicante Alicante Spain
| | - Cristina Almansa
- Research Technical Services (SSTTI), Microscopy UnitUniversity of Alicante Alicante Spain
| | - Mercedes Moreno‐Paz
- Department of Molecular EvolutionCentro de Astrobiología (INTA‐CSIC) Madrid Spain
| | - Yolanda Blanco
- Department of Molecular EvolutionCentro de Astrobiología (INTA‐CSIC) Madrid Spain
| | | | | | | | | | - Ramon Rosselló‐Móra
- Department of BiologyGraduate School of Sciences, Eskisehir Technical University Yunusemre Campus, Eskisehir 26470 Turkey
| | - Josefa Antón
- Department of Physiology, Genetics and MicrobiologyUniversity of Alicante Alicante Spain
| | - Víctor Parro
- Department of Molecular EvolutionCentro de Astrobiología (INTA‐CSIC) Madrid Spain
| |
Collapse
|
11
|
Rodela ML, Sabet S, Peterson A, Dillon JG. Broad Environmental Tolerance for a Salicola Host-Phage Pair Isolated from the Cargill Solar Saltworks, Newark, CA, USA. Microorganisms 2019; 7:E106. [PMID: 31010175 PMCID: PMC6518143 DOI: 10.3390/microorganisms7040106] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/13/2019] [Accepted: 04/17/2019] [Indexed: 11/29/2022] Open
Abstract
Phages greatly influence the ecology and evolution of their bacterial hosts; however, compared to hosts, a relatively low number of phages, especially halophilic phages, have been studied. This study describes a comparative investigation of physicochemical tolerance between a strain of the halophilic bacterium, Salicola, isolated from the Cargill Saltworks (Newark, CA, USA) and its associated phage. The host grew in media between pH 6-8.5, had a salinity growth optimum of 20% total salts (ranging from 10%-30%) and an upper temperature growth limit of 48 °C. The host utilized 61 of 190 substrates tested using BIOLOG Phenotype MicroArrays. The CGφ29 phage, one of only four reported Salicola phages, is a DNA virus of the Siphoviridae family. Overall, the phage tolerated a broader range of environmental conditions than its host (salinity 0-30% total salts; pH 3-9; upper thermal limit 80 °C) and is the most thermotolerant halophilic phage ever reported. This study is the most comprehensive investigation to date of a Salicola host-phage pair and provides novel insights into extreme environmental tolerances among bacteriophages.
Collapse
Affiliation(s)
- Meghan L Rodela
- Department of Biological Sciences, California State University, Long Beach, CA 90840, USA.
| | - Shereen Sabet
- Department of Biological Sciences, California State University, Long Beach, CA 90840, USA.
| | - Allison Peterson
- Department of Biological Sciences, California State University, Long Beach, CA 90840, USA.
| | - Jesse G Dillon
- Department of Biological Sciences, California State University, Long Beach, CA 90840, USA.
| |
Collapse
|
12
|
Mizuno CM, Prajapati B, Lucas‐Staat S, Sime‐Ngando T, Forterre P, Bamford DH, Prangishvili D, Krupovic M, Oksanen HM. Novel haloarchaeal viruses from Lake Retba infecting
Haloferax
and
Halorubrum
species. Environ Microbiol 2019; 21:2129-2147. [DOI: 10.1111/1462-2920.14604] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 03/15/2019] [Accepted: 03/21/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Carolina M. Mizuno
- Unité Biologie Moléculaire du Gène chez les ExtrêmophilesInstitut Pasteur, 25 rue du Docteur Roux 75015, Paris France
| | - Bina Prajapati
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental SciencesUniversity of Helsinki Finland
| | - Soizick Lucas‐Staat
- Unité Biologie Moléculaire du Gène chez les ExtrêmophilesInstitut Pasteur, 25 rue du Docteur Roux 75015, Paris France
| | - Telesphore Sime‐Ngando
- CNRS UMR 6023, Université Clermont‐AuvergneLaboratoire "Microorganismes: Génome et Environnement" (LMGE) F‐63000, Clermont‐Ferrand France
| | - Patrick Forterre
- Unité Biologie Moléculaire du Gène chez les ExtrêmophilesInstitut Pasteur, 25 rue du Docteur Roux 75015, Paris France
| | - Dennis H. Bamford
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental SciencesUniversity of Helsinki Finland
| | - David Prangishvili
- Unité Biologie Moléculaire du Gène chez les ExtrêmophilesInstitut Pasteur, 25 rue du Docteur Roux 75015, Paris France
| | - Mart Krupovic
- Unité Biologie Moléculaire du Gène chez les ExtrêmophilesInstitut Pasteur, 25 rue du Docteur Roux 75015, Paris France
| | - Hanna M. Oksanen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental SciencesUniversity of Helsinki Finland
| |
Collapse
|
13
|
Complete Genome Sequence of the Model Halovirus PhiH1 (ΦH1). Genes (Basel) 2018; 9:genes9100493. [PMID: 30322017 PMCID: PMC6210493 DOI: 10.3390/genes9100493] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 10/05/2018] [Accepted: 10/08/2018] [Indexed: 11/17/2022] Open
Abstract
The halophilic myohalovirus Halobacterium virus phiH (ΦH) was first described in 1982 and was isolated from a spontaneously lysed culture of Halobacterium salinarum strain R1. Until 1994, it was used extensively as a model to study the molecular genetics of haloarchaea, but only parts of the viral genome were sequenced during this period. Using Sanger sequencing combined with high-coverage Illumina sequencing, the full genome sequence of the major variant (phiH1) of this halovirus has been determined. The dsDNA genome is 58,072 bp in length and carries 97 protein-coding genes. We have integrated this information with the previously described transcription mapping data. PhiH could be classified into Myoviridae Type1, Cluster 4 based on capsid assembly and structural proteins (VIRFAM). The closest relative was Natrialba virus phiCh1 (φCh1), which shared 63% nucleotide identity and displayed a high level of gene synteny. This close relationship was supported by phylogenetic tree reconstructions. The complete sequence of this historically important virus will allow its inclusion in studies of comparative genomics and virus diversity.
Collapse
|
14
|
Krupovic M, Cvirkaite-Krupovic V, Iranzo J, Prangishvili D, Koonin EV. Viruses of archaea: Structural, functional, environmental and evolutionary genomics. Virus Res 2017; 244:181-193. [PMID: 29175107 DOI: 10.1016/j.virusres.2017.11.025] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 11/20/2017] [Accepted: 11/20/2017] [Indexed: 11/18/2022]
Abstract
Viruses of archaea represent one of the most enigmatic parts of the virosphere. Most of the characterized archaeal viruses infect extremophilic hosts and display remarkable diversity of virion morphotypes, many of which have never been observed among viruses of bacteria or eukaryotes. The uniqueness of the virion morphologies is matched by the distinctiveness of the genomes of these viruses, with ∼75% of genes encoding unique proteins, refractory to functional annotation based on sequence analyses. In this review, we summarize the state-of-the-art knowledge on various aspects of archaeal virus genomics. First, we outline how structural and functional genomics efforts provided valuable insights into the functions of viral proteins and revealed intricate details of the archaeal virus-host interactions. We then highlight recent metagenomics studies, which provided a glimpse at the diversity of uncultivated viruses associated with the ubiquitous archaea in the oceans, including Thaumarchaeota, Marine Group II Euryarchaeota, and others. These findings, combined with the recent discovery that archaeal viruses mediate a rapid turnover of thaumarchaea in the deep sea ecosystems, illuminate the prominent role of these viruses in the biosphere. Finally, we discuss the origins and evolution of archaeal viruses and emphasize the evolutionary relationships between viruses and non-viral mobile genetic elements. Further exploration of the archaeal virus diversity as well as functional studies on diverse virus-host systems are bound to uncover novel, unexpected facets of the archaeal virome.
Collapse
Affiliation(s)
- Mart Krupovic
- Department of Microbiology, Institut Pasteur, 25 rue du Dr. Roux, Paris 75015, Paris, France.
| | | | - Jaime Iranzo
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, USA
| | - David Prangishvili
- Department of Microbiology, Institut Pasteur, 25 rue du Dr. Roux, Paris 75015, Paris, France
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, USA
| |
Collapse
|
15
|
Paul VG, Mormile MR. A case for the protection of saline and hypersaline environments: a microbiological perspective. FEMS Microbiol Ecol 2017; 93:3950317. [DOI: 10.1093/femsec/fix091] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 07/09/2017] [Indexed: 11/12/2022] Open
|
16
|
Ahlgren NA, Chen Y, Needham DM, Parada AE, Sachdeva R, Trinh V, Chen T, Fuhrman JA. Genome and epigenome of a novel marine Thaumarchaeota strain suggest viral infection, phosphorothioation DNA modification and multiple restriction systems. Environ Microbiol 2017; 19:2434-2452. [PMID: 28418097 DOI: 10.1111/1462-2920.13768] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 04/08/2017] [Accepted: 04/11/2017] [Indexed: 11/29/2022]
Abstract
Marine Thaumarchaeota are abundant ammonia-oxidizers but have few representative laboratory-cultured strains. We report the cultivation of Candidatus Nitrosomarinus catalina SPOT01, a novel strain that is less warm-temperature tolerant than other cultivated Thaumarchaeota. Using metagenomic recruitment, strain SPOT01 comprises a major portion of Thaumarchaeota (4-54%) in temperate Pacific waters. Its complete 1.36 Mbp genome possesses several distinguishing features: putative phosphorothioation (PT) DNA modification genes; a region containing probable viral genes; and putative urea utilization genes. The PT modification genes and an adjacent putative restriction enzyme (RE) operon likely form a restriction modification (RM) system for defence from foreign DNA. PacBio sequencing showed >98% methylation at two motifs, and inferred PT guanine modification of 19% of possible TGCA sites. Metagenomic recruitment also reveals the putative virus region and PT modification and RE genes are present in 18-26%, 9-14% and <1.5% of natural populations at 150 m with ≥85% identity to strain SPOT01. The presence of multiple probable RM systems in a highly streamlined genome suggests a surprising importance for defence from foreign DNA for dilute populations that infrequently encounter viruses or other cells. This new strain provides new insights into the ecology, including viral interactions, of this important group of marine microbes.
Collapse
Affiliation(s)
- Nathan A Ahlgren
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Yangyang Chen
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, China.,Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao, China.,Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - David M Needham
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Alma E Parada
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Rohan Sachdeva
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Vickie Trinh
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Ting Chen
- Bioinformatics Division, TNLIST, Department of Computer Science and Technology, Tsinghua University, Beijing, China
| | - Jed A Fuhrman
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| |
Collapse
|
17
|
The Viral Gene ORF79 Encodes a Repressor Regulating Induction of the Lytic Life Cycle in the Haloalkaliphilic Virus ϕCh1. J Virol 2017; 91:JVI.00206-17. [PMID: 28202757 DOI: 10.1128/jvi.00206-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 02/06/2017] [Indexed: 11/20/2022] Open
Abstract
In this study, we describe the construction of the first genetically modified mutant of a halovirus infecting haloalkaliphilic Archaea By random choice, we targeted ORF79, a currently uncharacterized viral gene of the haloalkaliphilic virus ϕCh1. We used a polyethylene glycol (PEG)-mediated transformation method to deliver a disruption cassette into a lysogenic strain of the haloalkaliphilic archaeon Natrialba magadii bearing ϕCh1 as a provirus. This approach yielded mutant virus particles carrying a disrupted version of ORF79. Disruption of ORF79 did not influence morphology of the mature virions. The mutant virus was able to infect cured strains of N. magadii, resulting in a lysogenic, ORF79-disrupted strain. Analysis of this strain carrying the mutant virus revealed a repressor function of ORF79. In the absence of gp79, onset of lysis and expression of viral proteins occurred prematurely compared to their timing in the wild-type strain. Constitutive expression of ORF79 in a cured strain of N. magadii reduced the plating efficiency of ϕCh1 by seven orders of magnitude. Overexpression of ORF79 in a lysogenic strain of N. magadii resulted in an inhibition of lysis and total absence of viral proteins as well as viral progeny. In further experiments, gp79 directly regulated the expression of the tail fiber protein ORF34 but did not influence the methyltransferase gene ORF94. Further, we describe the establishment of an inducible promoter for in vivo studies in N. magadiiIMPORTANCE Genetic analyses of haloalkaliphilic Archaea or haloviruses are only rarely reported. Therefore, only little insight into the in vivo roles of proteins and their functions has been gained so far. We used a reverse genetics approach to identify the function of a yet undescribed gene of ϕCh1. We provide evidence that gp79, a currently unknown protein of ϕCh1, acts as a repressor protein of the viral life cycle, affecting the transition from the lysogenic to the lytic state of the virus. Thus, repressor genes in other haloviruses could be identified by sequence homologies to gp79 in the future. Moreover, we describe the use of an inducible promoter of N. magadii Our work provides valuable tools for the identification of other unknown viral genes by our approach as well as for functional studies of proteins by inducible expression.
Collapse
|
18
|
Crits-Christoph A, Gelsinger DR, Ma B, Wierzchos J, Ravel J, Davila A, Casero MC, DiRuggiero J. Functional interactions of archaea, bacteria and viruses in a hypersaline endolithic community. Environ Microbiol 2016; 18:2064-77. [DOI: 10.1111/1462-2920.13259] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 02/08/2016] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Bing Ma
- Institute for Genome Sciences, University of Maryland School of Medicine; Baltimore MD USA
| | - Jacek Wierzchos
- Department of Biochemistry and Microbial Ecology; Museo Nacional de Ciencias Naturales - Consejo Superior de Investigaciones Científicas; Madrid Spain
| | - Jacques Ravel
- Institute for Genome Sciences, University of Maryland School of Medicine; Baltimore MD USA
| | | | - M. Cristina Casero
- Department of Biochemistry and Microbial Ecology; Museo Nacional de Ciencias Naturales - Consejo Superior de Investigaciones Científicas; Madrid Spain
| | | |
Collapse
|
19
|
Roux S, Enault F, Ravet V, Colombet J, Bettarel Y, Auguet JC, Bouvier T, Lucas-Staat S, Vellet A, Prangishvili D, Forterre P, Debroas D, Sime-Ngando T. Analysis of metagenomic data reveals common features of halophilic viral communities across continents. Environ Microbiol 2015; 18:889-903. [PMID: 26472517 DOI: 10.1111/1462-2920.13084] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 09/28/2015] [Accepted: 10/08/2015] [Indexed: 12/31/2022]
Abstract
Microbial communities from hypersaline ponds, dominated by halophilic archaea, are considered specific of such extreme conditions. The associated viral communities have accordingly been shown to display specific features, such as similar morphologies among different sites. However, little is known about the genetic diversity of these halophilic viral communities across the Earth. Here, we studied viral communities in hypersaline ponds sampled on the coast of Senegal (8-36% of salinity) using metagenomics approach, and compared them with hypersaline viromes from Australia and Spain. The specificity of hyperhalophilic viruses could first be demonstrated at a community scale, salinity being a strong discriminating factor between communities. For the major viral group detected in all samples (Caudovirales), only a limited number of halophilic Caudovirales clades were highlighted. These clades gather viruses from different continents and display consistent genetic composition, indicating that they represent related lineages with a worldwide distribution. Non-tailed hyperhalophilic viruses display a greater rate of gene transfer and recombination, with uncharacterized genes conserved across different kind of viruses and plasmids. Thus, hypersaline viral communities around the world appear to form a genetically consistent community that are likely to harbour new genes coding for enzymes specifically adapted to these environments.
Collapse
Affiliation(s)
- Simon Roux
- Université Blaise Pascal, Laboratoire 'Microorganismes: Génome et Environnement', Clermont Université, Clermont-Ferrand, France.,CNRS UMR 6023, LMGE, Aubière, France
| | - Francois Enault
- Université Blaise Pascal, Laboratoire 'Microorganismes: Génome et Environnement', Clermont Université, Clermont-Ferrand, France.,CNRS UMR 6023, LMGE, Aubière, France
| | - Viviane Ravet
- Université Blaise Pascal, Laboratoire 'Microorganismes: Génome et Environnement', Clermont Université, Clermont-Ferrand, France.,CNRS UMR 6023, LMGE, Aubière, France
| | - Jonathan Colombet
- Université Blaise Pascal, Laboratoire 'Microorganismes: Génome et Environnement', Clermont Université, Clermont-Ferrand, France.,CNRS UMR 6023, LMGE, Aubière, France
| | - Yvan Bettarel
- IRD UMR 5119 ECOSYM, Université Montpellier 2, Montpellier, 34095, France
| | - Jean-Christophe Auguet
- Marine Biodiversity, Exploitation and Conservation (MARBEC), UMR CNRS 9190, Montpellier University, Place Eugéne Bataillon, Montpellier, France
| | - Thierry Bouvier
- IRD UMR 5119 ECOSYM, Université Montpellier 2, Montpellier, 34095, France
| | - Soizick Lucas-Staat
- Unité Biologie Moléculaire du Gène chez les Extrêmophiles, Département de Microbiologie, Institut Pasteur, Paris, France
| | - Agnès Vellet
- Université Blaise Pascal, Laboratoire 'Microorganismes: Génome et Environnement', Clermont Université, Clermont-Ferrand, France.,CNRS UMR 6023, LMGE, Aubière, France
| | - David Prangishvili
- Unité Biologie Moléculaire du Gène chez les Extrêmophiles, Département de Microbiologie, Institut Pasteur, Paris, France
| | - Patrick Forterre
- Unité Biologie Moléculaire du Gène chez les Extrêmophiles, Département de Microbiologie, Institut Pasteur, Paris, France.,Laboratoire de Biologie Moléculaire du Gène chez les Extrêmophiles, CNRS UMR 8621, Université Paris Sud, Institut de Génétique et Microbiologie, Orsay, France
| | - Didier Debroas
- Université Blaise Pascal, Laboratoire 'Microorganismes: Génome et Environnement', Clermont Université, Clermont-Ferrand, France.,CNRS UMR 6023, LMGE, Aubière, France
| | - Telesphore Sime-Ngando
- Université Blaise Pascal, Laboratoire 'Microorganismes: Génome et Environnement', Clermont Université, Clermont-Ferrand, France.,CNRS UMR 6023, LMGE, Aubière, France
| |
Collapse
|
20
|
Abstract
SUMMARY Research on archaeal extrachromosomal genetic elements (ECEs) has progressed rapidly in the past decade. To date, over 60 archaeal viruses and 60 plasmids have been isolated. These archaeal viruses exhibit an exceptional diversity in morphology, with a wide array of shapes, such as spindles, rods, filaments, spheres, head-tails, bottles, and droplets, and some of these new viruses have been classified into one order, 10 families, and 16 genera. Investigation of model archaeal viruses has yielded important insights into mechanisms underlining various steps in the viral life cycle, including infection, DNA replication and transcription, and virion egression. Many of these mechanisms are unprecedented for any known bacterial or eukaryal viruses. Studies of plasmids isolated from different archaeal hosts have also revealed a striking diversity in gene content and innovation in replication strategies. Highly divergent replication proteins are identified in both viral and plasmid genomes. Genomic studies of archaeal ECEs have revealed a modular sequence structure in which modules of DNA sequence are exchangeable within, as well as among, plasmid families and probably also between viruses and plasmids. In particular, it has been suggested that ECE-host interactions have shaped the coevolution of ECEs and their archaeal hosts. Furthermore, archaeal hosts have developed defense systems, including the innate restriction-modification (R-M) system and the adaptive CRISPR (clustered regularly interspaced short palindromic repeats) system, to restrict invasive plasmids and viruses. Together, these interactions permit a delicate balance between ECEs and their hosts, which is vitally important for maintaining an innovative gene reservoir carried by ECEs. In conclusion, while research on archaeal ECEs has just started to unravel the molecular biology of these genetic entities and their interactions with archaeal hosts, it is expected to accelerate in the next decade.
Collapse
|
21
|
Abstract
Hypersaline waters and salt crystals are known to contain high numbers of haloarchaeal cells and their viruses. Both culture-dependent and culture-independent studies indicate that these viruses represent a world-wide distributed reservoir of orphan genes and possibly novel virion morphotypes. To date, 90 viruses have been described for halophilic archaeal hosts, all belonging to the Halobacteriaceae family. This number is higher than that described for the members of any other archaeal family, but still very low compared to the viruses of bacteria and eukaryotes. The known haloarchaeal viruses represent icosahedral tailed, icosahedral internal membrane-containing, pleomorphic, and spindle-shaped virion morphotypes. This morphotype distribution is low, especially when compared to the astronomical number (>10(31)) of viruses on Earth. This strongly suggests that only certain protein folds are capable of making a functional virion. Viruses infecting cells belonging to any of the three domains of life are known to share similar major capsid protein folds which can be used to classify viruses into structure-based lineages. The latest observation supporting this proposal comes from the studies of icosahedral tailed haloarchaeal viruses which are the most abundant virus isolates from hypersaline environments. These viruses were shown to have the same major capsid protein fold (HK97-fold) with tailed bacteriophages belonging to the order Caudovirales and with eukaryotic herpes viruses. This proposes that these viruses have a common origin dating back to ancient times. Here we summarize the current knowledge of haloarchaeal viruses from the perspective of virus morphotypes.
Collapse
|
22
|
Tschitschko B, Williams TJ, Allen MA, Páez-Espino D, Kyrpides N, Zhong L, Raftery MJ, Cavicchioli R. Antarctic archaea-virus interactions: metaproteome-led analysis of invasion, evasion and adaptation. ISME JOURNAL 2015; 9:2094-107. [PMID: 26125682 DOI: 10.1038/ismej.2015.110] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 04/15/2015] [Accepted: 05/19/2015] [Indexed: 01/21/2023]
Abstract
Despite knowledge that viruses are abundant in natural ecosystems, there is limited understanding of which viruses infect which hosts, and how both hosts and viruses respond to those interactions-interactions that ultimately shape community structure and dynamics. In Deep Lake, Antarctica, intergenera gene exchange occurs rampantly within the low complexity, haloarchaea-dominated community, strongly balanced by distinctions in niche adaptation which maintain sympatric speciation. By performing metaproteomics for the first time on haloarchaea, genomic variation of S-layer, archaella and other cell surface proteins was linked to mechanisms of infection evasion. CRISPR defense systems were found to be active, with haloarchaea responding to at least eight distinct types of viruses, including those infecting between genera. The role of BREX systems in defending against viruses was also examined. Although evasion and defense were evident, both hosts and viruses also may benefit from viruses carrying and expressing host genes, thereby potentially enhancing genetic variation and phenotypic differences within populations. The data point to a complex inter-play leading to a dynamic optimization of host-virus interactions. This comprehensive overview was achieved only through the integration of results from metaproteomics, genomics and metagenomics.
Collapse
Affiliation(s)
- Bernhard Tschitschko
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, New South Wales, Australia
| | - Timothy J Williams
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, New South Wales, Australia
| | - Michelle A Allen
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, New South Wales, Australia
| | | | - Nikos Kyrpides
- Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Ling Zhong
- Bioanalytical Mass Spectrometry Facility, The University of New South Wales, Sydney, New South Wales, Australia
| | - Mark J Raftery
- Bioanalytical Mass Spectrometry Facility, The University of New South Wales, Sydney, New South Wales, Australia
| | - Ricardo Cavicchioli
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, New South Wales, Australia
| |
Collapse
|
23
|
Luk AWS, Williams TJ, Erdmann S, Papke RT, Cavicchioli R. Viruses of haloarchaea. Life (Basel) 2014; 4:681-715. [PMID: 25402735 PMCID: PMC4284463 DOI: 10.3390/life4040681] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 10/23/2014] [Accepted: 10/24/2014] [Indexed: 12/26/2022] Open
Abstract
In hypersaline environments, haloarchaea (halophilic members of the Archaea) are the dominant organisms, and the viruses that infect them, haloarchaeoviruses are at least ten times more abundant. Since their discovery in 1974, described haloarchaeoviruses include head-tailed, pleomorphic, spherical and spindle-shaped morphologies, representing Myoviridae, Siphoviridae, Podoviridae, Pleolipoviridae, Sphaerolipoviridae and Fuselloviridae families. This review overviews current knowledge of haloarchaeoviruses, providing information about classification, morphotypes, macromolecules, life cycles, genetic manipulation and gene regulation, and host-virus responses. In so doing, the review incorporates knowledge from laboratory studies of isolated viruses, field-based studies of environmental samples, and both genomic and metagenomic analyses of haloarchaeoviruses. What emerges is that some haloarchaeoviruses possess unique morphological and life cycle properties, while others share features with other viruses (e.g., bacteriophages). Their interactions with hosts influence community structure and evolution of populations that exist in hypersaline environments as diverse as seawater evaporation ponds, to hot desert or Antarctic lakes. The discoveries of their wide-ranging and important roles in the ecology and evolution of hypersaline communities serves as a strong motivator for future investigations of both laboratory-model and environmental systems.
Collapse
Affiliation(s)
- Alison W S Luk
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia.
| | - Timothy J Williams
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia.
| | - Susanne Erdmann
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia.
| | - R Thane Papke
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269-3125, USA.
| | - Ricardo Cavicchioli
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia.
| |
Collapse
|
24
|
Clokie MR, Millard AD, Letarov AV, Heaphy S. Phages in nature. BACTERIOPHAGE 2014; 1:31-45. [PMID: 21687533 DOI: 10.4161/bact.1.1.14942] [Citation(s) in RCA: 648] [Impact Index Per Article: 64.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 01/17/2011] [Accepted: 01/18/2011] [Indexed: 12/28/2022]
Abstract
Bacteriophages or phages are the most abundant organisms in the biosphere and they are a ubiquitous feature of prokaryotic existence. A bacteriophage is a virus which infects a bacterium. Archaea are also infected by viruses, whether these should be referred to as 'phages' is debatable, but they are included as such in the scope this article. Phages have been of interest to scientists as tools to understand fundamental molecular biology, as vectors of horizontal gene transfer and drivers of bacterial evolution, as sources of diagnostic and genetic tools and as novel therapeutic agents. Unraveling the biology of phages and their relationship with their hosts is key to understanding microbial systems and their exploitation. In this article we describe the roles of phages in different host systems and show how modeling, microscopy, isolation, genomic and metagenomic based approaches have come together to provide unparalleled insights into these small but vital constituents of the microbial world.
Collapse
Affiliation(s)
- Martha Rj Clokie
- Department of Infection, Immunity and Inflammation; Medical Sciences Building; University of Leicester; Leicester, UK
| | | | | | | |
Collapse
|
25
|
Raymann K, Forterre P, Brochier-Armanet C, Gribaldo S. Global phylogenomic analysis disentangles the complex evolutionary history of DNA replication in archaea. Genome Biol Evol 2014; 6:192-212. [PMID: 24398374 PMCID: PMC3914693 DOI: 10.1093/gbe/evu004] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The archaeal machinery responsible for DNA replication is largely homologous to that of eukaryotes and is clearly distinct from its bacterial counterpart. Moreover, it shows high diversity in the various archaeal lineages, including different sets of components, heterogeneous taxonomic distribution, and a large number of additional copies that are sometimes highly divergent. This has made the evolutionary history of this cellular system particularly challenging to dissect. Here, we have carried out an exhaustive identification of homologs of all major replication components in over 140 complete archaeal genomes. Phylogenomic analysis allowed assigning them to either a conserved and probably essential core of replication components that were mainly vertically inherited, or to a variable and highly divergent shell of extra copies that have likely arisen from integrative elements. This suggests that replication proteins are frequently exchanged between extrachromosomal elements and cellular genomes. Our study allowed clarifying the history that shaped this key cellular process (ancestral components, horizontal gene transfers, and gene losses), providing important evolutionary and functional information. Finally, our precise identification of core components permitted to show that the phylogenetic signal carried by DNA replication is highly consistent with that harbored by two other key informational machineries (translation and transcription), strengthening the existence of a robust organismal tree for the Archaea.
Collapse
Affiliation(s)
- Kasie Raymann
- Département de Microbiologie, Institut Pasteur, Unité Biologie Moléculaire du Gene chez les Extrêmophiles, Paris, France
| | | | | | | |
Collapse
|
26
|
Abstract
The Archaea-and their viruses-remain the most enigmatic of life's three domains. Once thought to inhabit only extreme environments, archaea are now known to inhabit diverse environments. Even though the first archaeal virus was described over 40 years ago, only 117 archaeal viruses have been discovered to date. Despite this small number, these viruses have painted a portrait of enormous morphological and genetic diversity. For example, research centered around the various steps of the archaeal virus life cycle has led to the discovery of unique mechanisms employed by archaeal viruses during replication, maturation, and virion release. In many instances, archaeal virus proteins display very low levels of sequence homology to other proteins listed in the public database, and therefore, structural characterization of these proteins has played an integral role in functional assignment. These structural studies have not only provided insights into structure-function relationships but have also identified links between viruses across all three domains of life.
Collapse
Affiliation(s)
- Nikki Dellas
- Thermal Biology Institute and Departments of.,Plant Sciences and
| | - Jamie C Snyder
- Thermal Biology Institute and Departments of.,Plant Sciences and
| | - Benjamin Bolduc
- Thermal Biology Institute and Departments of.,Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717;
| | - Mark J Young
- Thermal Biology Institute and Departments of.,Plant Sciences and
| |
Collapse
|
27
|
Aljarbou AN, Aljofan M. Genotyping, morphology and molecular characteristics of a lytic phage of Neisseria strain obtained from infected human dental plaque. J Microbiol 2014; 52:609-18. [PMID: 24879345 DOI: 10.1007/s12275-014-3380-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 03/03/2014] [Accepted: 03/12/2014] [Indexed: 11/26/2022]
Abstract
The lytic bacteriaphage (phage) A2 was isolated from human dental plaques along with its bacterial host. The virus was found to have an icosahedron-shaped head (60±3 nm), a sheathed and rigid long tail (∼175 nm) and was categorized into the family Siphoviridae of the order Caudovirales, which are dsDNA viral family, characterised by their ability to infect bacteria and are nonenveloped with a noncontractile tail. The isolated phage contained a linear dsDNA genome having 31,703 base pairs of unique sequence, which were sorted into three contigs and 12 single sequences. A latent period of 25 minutes and burst size of 24±2 particles was determined for the virus. Bioinformatics approaches were used to identify ORFs in the genome. A phylogenetic analysis confirmed the species inter-relationship and its placement in the family.
Collapse
Affiliation(s)
- Ahmed N Aljarbou
- Department of Pharmaceutics, College of Pharmacy, Qassim University, Qassim, Saudi Arabia,
| | | |
Collapse
|
28
|
Protein-protein interactions leading to recruitment of the host DNA sliding clamp by the hyperthermophilic Sulfolobus islandicus rod-shaped virus 2. J Virol 2014; 88:7105-8. [PMID: 24696494 DOI: 10.1128/jvi.00636-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Viruses infecting hyperthermophilic archaea typically do not encode DNA polymerases, raising questions regarding their genome replication. Here, using a yeast two-hybrid approach, we have assessed interactions between proteins of Sulfolobus islandicus rod-shaped virus 2 (SIRV2) and the host-encoded proliferating cell nuclear antigen (PCNA), a key DNA replication protein in archaea. Five SIRV2 proteins were found to interact with PCNA, providing insights into the recruitment of host replisome for viral DNA replication.
Collapse
|
29
|
Senčilo A, Roine E. A Glimpse of the genomic diversity of haloarchaeal tailed viruses. Front Microbiol 2014; 5:84. [PMID: 24659986 PMCID: PMC3950731 DOI: 10.3389/fmicb.2014.00084] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 02/17/2014] [Indexed: 11/13/2022] Open
Abstract
Tailed viruses are the most common isolates infecting prokaryotic hosts residing in hypersaline environments. Archaeal tailed viruses represent only a small portion of all characterized tailed viruses of prokaryotes. But even this small dataset revealed that archaeal tailed viruses have many similarities to their counterparts infecting bacteria, the bacteriophages. Shared functional homologs and similar genome organizations suggested that all microbial tailed viruses have common virion architectural and assembly principles. Recent structural studies have provided evidence justifying this thereby grouping archaeal and bacterial tailed viruses into a single lineage. Currently there are 17 haloarchaeal tailed viruses with entirely sequenced genomes. Nine viruses have at least one close relative among the 17 viruses and, according to the similarities, can be divided into three groups. Two other viruses share some homologs and therefore are distantly related, whereas the rest of the viruses are rather divergent (or singletons). Comparative genomics analysis of these viruses offers a glimpse into the genetic diversity and structure of haloarchaeal tailed virus communities.
Collapse
Affiliation(s)
- Ana Senčilo
- Department of Biosciences and Institute of Biotechnology, University of Helsinki Helsinki, Finland
| | - Elina Roine
- Department of Biosciences and Institute of Biotechnology, University of Helsinki Helsinki, Finland
| |
Collapse
|
30
|
Li M, Wang R, Zhao D, Xiang H. Adaptation of the Haloarcula hispanica CRISPR-Cas system to a purified virus strictly requires a priming process. Nucleic Acids Res 2013; 42:2483-92. [PMID: 24265226 PMCID: PMC3936756 DOI: 10.1093/nar/gkt1154] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The clustered regularly interspaced short palindromic repeat (CRISPR)-Cas system mediates adaptive immunity against foreign nucleic acids in prokaryotes. However, efficient adaptation of a native CRISPR to purified viruses has only been observed for the type II-A system from a Streptococcus thermophilus industry strain, and rarely reported for laboratory strains. Here, we provide a second native system showing efficient adaptation. Infected by a newly isolated virus HHPV-2, Haloarcula hispanica type I-B CRISPR system acquired spacers discriminatively from viral sequences. Unexpectedly, in addition to Cas1, Cas2 and Cas4, this process also requires Cas3 and at least partial Cascade proteins, which are involved in interference and/or CRISPR RNA maturation. Intriguingly, a preexisting spacer partially matching a viral sequence is also required, and spacer acquisition from upstream and downstream sequences of its target sequence (i.e. priming protospacer) shows different strand bias. These evidences strongly indicate that adaptation in this system strictly requires a priming process. This requirement, if validated also true for other CRISPR systems as implied by our bioinformatic analysis, may help to explain failures to observe efficient adaptation to purified viruses in many laboratory strains, and the discrimination mechanism at the adaptation level that has confused scientists for years.
Collapse
Affiliation(s)
- Ming Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China and University of Chinese Academy of Sciences, Beijing 100049, China
| | | | | | | |
Collapse
|
31
|
High level of intergenera gene exchange shapes the evolution of haloarchaea in an isolated Antarctic lake. Proc Natl Acad Sci U S A 2013; 110:16939-44. [PMID: 24082106 DOI: 10.1073/pnas.1307090110] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Deep Lake in Antarctica is a globally isolated, hypersaline system that remains liquid at temperatures down to -20 °C. By analyzing metagenome data and genomes of four isolates we assessed genome variation and patterns of gene exchange to learn how the lake community evolved. The lake is completely and uniformly dominated by haloarchaea, comprising a hierarchically structured, low-complexity community that differs greatly to temperate and tropical hypersaline environments. The four Deep Lake isolates represent distinct genera (∼85% 16S rRNA gene similarity and ∼73% genome average nucleotide identity) with genomic characteristics indicative of niche adaptation, and collectively account for ∼72% of the cellular community. Network analysis revealed a remarkable level of intergenera gene exchange, including the sharing of long contiguous regions (up to 35 kb) of high identity (∼100%). Although the genomes of closely related Halobacterium, Haloquadratum, and Haloarcula (>90% average nucleotide identity) shared regions of high identity between species or strains, the four Deep Lake isolates were the only distantly related haloarchaea to share long high-identity regions. Moreover, the Deep Lake high-identity regions did not match to any other hypersaline environment metagenome data. The most abundant species, tADL, appears to play a central role in the exchange of insertion sequences, but not the exchange of high-identity regions. The genomic characteristics of the four haloarchaea are consistent with a lake ecosystem that sustains a high level of intergenera gene exchange while selecting for ecotypes that maintain sympatric speciation. The peculiarities of this polar system restrict which species can grow and provide a tempo and mode for accentuating gene exchange.
Collapse
|
32
|
PH1: an archaeovirus of Haloarcula hispanica related to SH1 and HHIV-2. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2013; 2013:456318. [PMID: 23585730 PMCID: PMC3622292 DOI: 10.1155/2013/456318] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 01/07/2013] [Indexed: 11/24/2022]
Abstract
Halovirus PH1 infects Haloarcula hispanica and was isolated from an Australian salt lake. The burst size in single-step growth conditions was 50–100 PFU/cell, but cell density did not decrease until well after the rise (4–6 hr p.i.), indicating that the virus could exit without cell lysis. Virions were round, 51 nm in diameter, displayed a layered capsid structure, and were sensitive to chloroform and lowered salt concentration. The genome is linear dsDNA, 28,064 bp in length, with 337 bp terminal repeats and terminal proteins, and could transfect haloarchaeal species belonging to five different genera. The genome is predicted to carry 49 ORFs, including those for structural proteins, several of which were identified by mass spectroscopy. The close similarity of PH1 to SH1 (74% nucleotide identity) allowed a detailed description and analysis of the differences (divergent regions) between the two genomes, including the detection of repeat-mediated deletions. The relationship of SH1-like and pleolipoviruses to previously described genomic loci of virus and plasmid-related elements (ViPREs) of haloarchaea revealed an extensive level of recombination between the known haloviruses. PH1 is a member of the same virus group as SH1 and HHIV-2, and we propose the name halosphaerovirus to accommodate these viruses.
Collapse
|
33
|
Senčilo A, Jacobs-Sera D, Russell DA, Ko CC, Bowman CA, Atanasova NS, Österlund E, Oksanen HM, Bamford DH, Hatfull GF, Roine E, Hendrix RW. Snapshot of haloarchaeal tailed virus genomes. RNA Biol 2013; 10:803-16. [PMID: 23470522 DOI: 10.4161/rna.24045] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The complete genome sequences of archaeal tailed viruses are currently highly underrepresented in sequence databases. Here, we report the genomic sequences of 10 new tailed viruses infecting different haloarchaeal hosts. Among these, only two viral genomes are closely related to each other and to previously described haloviruses HF1 and HF2. The approximately 760 kb of new genomic sequences in total shows no matches to CRISPR/Cas spacer sequences in haloarchaeal host genomes. Despite their high divergence, we were able to identify virion structural and assembly genes as well as genes coding for DNA and RNA metabolic functions. Interestingly, we identified many genes and genomic features that are shared with tailed bacteriophages, consistent with the hypothesis that haloarchaeal and bacterial tailed viruses share common ancestry, and that a viral lineage containing archaeal viruses, bacteriophages and eukaryotic viruses predates the division of the three major domains of non-viral life. However, as in tailed viruses in general and in haloarchaeal tailed viruses in particular, there are still a considerable number of predicted genes of unknown function.
Collapse
Affiliation(s)
- Ana Senčilo
- Department of Biosciences and Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Abstract
Extremophilic archaea, both hyperthermophiles and halophiles, dominate in habitats where rather harsh conditions are encountered. Like all other organisms, archaeal cells are susceptible to viral infections, and to date, about 100 archaeal viruses have been described. Among them, there are extraordinary virion morphologies as well as the common head-tailed viruses. Although approximately half of the isolated archaeal viruses belong to the latter group, no three-dimensional virion structures of these head-tailed viruses are available. Thus, rigorous comparisons with bacteriophages are not yet warranted. In the present study, we determined the genome sequences of two of such viruses of halophiles and solved their capsid structures by cryo-electron microscopy and three-dimensional image reconstruction. We show that these viruses are inactivated, yet remain intact, at low salinity and that their infectivity is regained when high salinity is restored. This enabled us to determine their three-dimensional capsid structures at low salinity to a ∼10-Å resolution. The genetic and structural data showed that both viruses belong to the same T-number class, but one of them has enlarged its capsid to accommodate a larger genome than typically associated with a T=7 capsid by inserting an additional protein into the capsid lattice.
Collapse
|
35
|
Lim YW, Schmieder R, Haynes M, Willner D, Furlan M, Youle M, Abbott K, Edwards R, Evangelista J, Conrad D, Rohwer F. Metagenomics and metatranscriptomics: windows on CF-associated viral and microbial communities. J Cyst Fibros 2012; 12:154-64. [PMID: 22951208 DOI: 10.1016/j.jcf.2012.07.009] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 07/15/2012] [Accepted: 07/27/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND Samples collected from CF patient airways often contain large amounts of host-derived nucleic acids that interfere with recovery and purification of microbial and viral nucleic acids. This study describes metagenomic and metatranscriptomic methods that address these issues. METHODS Microbial and viral metagenomes, and microbial metatranscriptomes, were successfully prepared from sputum samples from five adult CF patients. RESULTS Contaminating host DNA was dramatically reduced in the metagenomes. Each CF patient presented a unique microbiome; in some Pseudomonas aeruginosa was replaced by other opportunistic bacteria. Even though the taxonomic composition of the microbiomes is very different, the metabolic potentials encoded by the community are very similar. The viral communities were dominated by phages that infect major CF pathogens. The metatranscriptomes reveal differential expression of encoded metabolic potential with changing health status. CONCLUSIONS Microbial and viral metagenomics combined with microbial transcriptomics characterize the dynamic polymicrobial communities found in CF airways, revealing both the taxa present and their current metabolic activities. These approaches can facilitate the development of individualized treatment plans and novel therapeutic approaches.
Collapse
Affiliation(s)
- Yan Wei Lim
- Department of Biology, San Diego State University, San Diego, CA, 92182, USA.
| | - Robert Schmieder
- Computational Science Research Center, San Diego State University, San Diego, CA, 92182, USA
| | - Matthew Haynes
- Department of Biology, San Diego State University, San Diego, CA, 92182, USA; DOE Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Dana Willner
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, QLD, Australia
| | - Mike Furlan
- Department of Biology, San Diego State University, San Diego, CA, 92182, USA
| | | | - Katelynn Abbott
- Department of Biology, San Diego State University, San Diego, CA, 92182, USA
| | - Robert Edwards
- Computational Science Research Center, San Diego State University, San Diego, CA, 92182, USA; Mathematics and Computer Science Division, Argonne National, Laboratory, Argonne, IL 60439, USA
| | - Jose Evangelista
- Department of Medicine, University of California San Diego, La Jolla, CA 92037, USA
| | - Douglas Conrad
- Department of Medicine, University of California San Diego, La Jolla, CA 92037, USA
| | - Forest Rohwer
- Department of Biology, San Diego State University, San Diego, CA, 92182, USA
| |
Collapse
|
36
|
Dynamic viral populations in hypersaline systems as revealed by metagenomic assembly. Appl Environ Microbiol 2012; 78:6309-20. [PMID: 22773627 DOI: 10.1128/aem.01212-12] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Viruses of the Bacteria and Archaea play important roles in microbial evolution and ecology, and yet viral dynamics in natural systems remain poorly understood. Here, we created de novo assemblies from 6.4 Gbp of metagenomic sequence from eight community viral concentrate samples, collected from 12 h to 3 years apart from hypersaline Lake Tyrrell (LT), Victoria, Australia. Through extensive manual assembly curation, we reconstructed 7 complete and 28 partial novel genomes of viruses and virus-like entities (VLEs, which could be viruses or plasmids). We tracked these 35 populations across the eight samples and found that they are generally stable on the timescale of days and transient on the timescale of years, with some exceptions. Cross-detection of the 35 LT populations in three previously described haloviral metagenomes was limited to a few genes, and most previously sequenced haloviruses were not detected in our samples, though 3 were detected upon reducing our detection threshold from 90% to 75% nucleotide identity. Similar results were obtained when we applied our methods to haloviral metagenomic data previously reported from San Diego, CA: 10 contigs that we assembled from that system exhibited a variety of detection patterns on a timescale of weeks to 1 month but were generally not detected in LT. Our results suggest that most haloviral populations have a limited or, possibly, a temporally variable global distribution. This study provides high-resolution insight into viral biogeography and dynamics and it places "snapshot" viral metagenomes, collected at a single time and location, in context.
Collapse
|
37
|
Reconstructing viral genomes from the environment using fosmid clones: the case of haloviruses. PLoS One 2012; 7:e33802. [PMID: 22479446 PMCID: PMC3316494 DOI: 10.1371/journal.pone.0033802] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Accepted: 02/22/2012] [Indexed: 12/26/2022] Open
Abstract
Background Metaviriomes, the viral genomes present in an environment, have been studied by direct sequencing of the viral DNA or by cloning in small insert libraries. The short reads generated by both approaches make it very difficult to assemble and annotate such flexible genomic entities. Many environmental viruses belong to unknown groups or prey on uncultured and little known cellular lineages, and hence might not be present in databases. Methodology and Principal Findings Here we have used a different approach, the cloning of viral DNA into fosmids before sequencing, to obtain natural contigs that are close to the size of a viral genome. We have studied a relatively low diversity extreme environment: saturated NaCl brines, which simplifies the analysis and interpretation of the data. Forty-two different viral genomes were retrieved, and some of these were almost complete, and could be tentatively identified as head-tail phages (Caudovirales). Conclusions and Significance We found a cluster of phage genomes that most likely infect Haloquadratum walsbyi, the square archaeon and major component of the community in these hypersaline habitats. The identity of the prey could be confirmed by the presence of CRISPR spacer sequences shared by the virus and one of the available strain genomes. Other viral clusters detected appeared to prey on the Nanohaloarchaea and on the bacterium Salinibacter ruber, covering most of the diversity of microbes found in this type of environment. This approach appears then as a viable alternative to describe metaviriomes in a much more detailed and reliable way than by the more common approaches based on direct sequencing. An example of transfer of a CRISPR cluster including repeats and spacers was accidentally found supporting the dynamic nature and frequent transfer of this peculiar prokaryotic mechanism of cell protection.
Collapse
|
38
|
Gorlas A, Koonin EV, Bienvenu N, Prieur D, Geslin C. TPV1, the first virus isolated from the hyperthermophilic genus Thermococcus. Environ Microbiol 2011; 14:503-16. [PMID: 22151304 DOI: 10.1111/j.1462-2920.2011.02662.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We describe a novel virus, TPV1 (Thermococcus prieurii virus 1), which was discovered in a hyperthermophilic euryarchaeote isolated from a deep-sea hydrothermal chimney sample collected at a depth of 2700 m at the East Pacific Rise. TPV1 is the first virus isolated and characterized from the hyperthermophilic euryarchaeal genus Thermococcus. TPV1 particles have a lemon-shaped morphology (140 nm × 80 nm) similar to the structures previously reported for Fuselloviruses and for the unclassified virus-like particle PAV1 (Pyrococcus abyssi virus 1). The infection with TPV1 does not cause host lysis and viral replication can be induced by UV irradiation. TPV1 contains a double-stranded circular DNA of 21.5 kb, which is also present in high copy number in a free form in the host cell. The TPV1 genome encompasses 28 predicted genes; the protein sequences encoded in 16 of these genes show no significant similarity to proteins in public databases. Proteins predicted to be involved in genome replication were identified as well as transcriptional regulators. TPV1 encodes also a predicted integrase of the tyrosine recombinase family. The only two genes that are homologous between TPV1 and PAV1 are TPV1-22 and TPV1-23, which encode proteins containing a concanavalin A-like lectin/glucanase domain that might be involved in virus-host recognition.
Collapse
Affiliation(s)
- Aurore Gorlas
- Laboratory of Microbiology of Extreme Environments, UMR 6197/CNRS/UBO IUEM, Place Nicolas Copernic, Technopôle Brest Iroise Plouzane, France
| | | | | | | | | |
Collapse
|
39
|
Krupovic M, Prangishvili D, Hendrix RW, Bamford DH. Genomics of bacterial and archaeal viruses: dynamics within the prokaryotic virosphere. Microbiol Mol Biol Rev 2011; 75:610-35. [PMID: 22126996 PMCID: PMC3232739 DOI: 10.1128/mmbr.00011-11] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Prokaryotes, bacteria and archaea, are the most abundant cellular organisms among those sharing the planet Earth with human beings (among others). However, numerous ecological studies have revealed that it is actually prokaryotic viruses that predominate on our planet and outnumber their hosts by at least an order of magnitude. An understanding of how this viral domain is organized and what are the mechanisms governing its evolution is therefore of great interest and importance. The vast majority of characterized prokaryotic viruses belong to the order Caudovirales, double-stranded DNA (dsDNA) bacteriophages with tails. Consequently, these viruses have been studied (and reviewed) extensively from both genomic and functional perspectives. However, albeit numerous, tailed phages represent only a minor fraction of the prokaryotic virus diversity. Therefore, the knowledge which has been generated for this viral system does not offer a comprehensive view of the prokaryotic virosphere. In this review, we discuss all families of bacterial and archaeal viruses that contain more than one characterized member and for which evolutionary conclusions can be attempted by use of comparative genomic analysis. We focus on the molecular mechanisms of their genome evolution as well as on the relationships between different viral groups and plasmids. It becomes clear that evolutionary mechanisms shaping the genomes of prokaryotic viruses vary between different families and depend on the type of the nucleic acid, characteristics of the virion structure, as well as the mode of the life cycle. We also point out that horizontal gene transfer is not equally prevalent in different virus families and is not uniformly unrestricted for diverse viral functions.
Collapse
Affiliation(s)
- Mart Krupovic
- Institut Pasteur, Unité Biologie Moléculaire du Gène chez les Extrêmophiles, Département de Microbiologie, 25 rue du Dr. Roux, 75015 Paris, France.
| | | | | | | |
Collapse
|
40
|
Dyall-Smith ML, Pfeiffer F, Klee K, Palm P, Gross K, Schuster SC, Rampp M, Oesterhelt D. Haloquadratum walsbyi: limited diversity in a global pond. PLoS One 2011; 6:e20968. [PMID: 21701686 PMCID: PMC3119063 DOI: 10.1371/journal.pone.0020968] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 05/14/2011] [Indexed: 12/03/2022] Open
Abstract
Background Haloquadratum walsbyi commonly dominates the microbial flora of hypersaline waters. Its cells are extremely fragile squares requiring >14%(w/v) salt for growth, properties that should limit its dispersal and promote geographical isolation and divergence. To assess this, the genome sequences of two isolates recovered from sites at near maximum distance on Earth, were compared. Principal Findings Both chromosomes are 3.1 MB in size, and 84% of each sequence was highly similar to the other (98.6% identity), comprising the core sequence. ORFs of this shared sequence were completely synteneic (conserved in genomic orientation and order), without inversion or rearrangement. Strain-specific insertions/deletions could be precisely mapped, often allowing the genetic events to be inferred. Many inferred deletions were associated with short direct repeats (4–20 bp). Deletion-coupled insertions are frequent, producing different sequences at identical positions. In cases where the inserted and deleted sequences are homologous, this leads to variant genes in a common synteneic background (as already described by others). Cas/CRISPR systems are present in C23T but have been lost in HBSQ001 except for a few spacer remnants. Numerous types of mobile genetic elements occur in both strains, most of which appear to be active, and with some specifically targetting others. Strain C23T carries two ∼6 kb plasmids that show similarity to halovirus His1 and to sequences nearby halovirus/plasmid gene clusters commonly found in haloarchaea. Conclusions Deletion-coupled insertions show that Hqr. walsbyi evolves by uptake and precise integration of foreign DNA, probably originating from close relatives. Change is also driven by mobile genetic elements but these do not by themselves explain the atypically low gene coding density found in this species. The remarkable genome conservation despite the presence of active systems for genome rearrangement implies both an efficient global dispersal system, and a high selective fitness for this species.
Collapse
Affiliation(s)
- Mike L Dyall-Smith
- Department of Membrane Biochemistry, Max-Planck-Institute of Biochemistry, Martinsried, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Abstract
Since their discovery in the early 1980s, viruses that infect the third domain of life, the Archaea, have captivated our attention because of their virions' unusual morphologies and proteins, which lack homologues in extant databases. Moreover, the life cycles of these viruses have unusual features, as revealed by the recent discovery of a novel virus egress mechanism that involves the formation of specific pyramidal structures on the host cell surface. The available data elucidate the particular nature of the archaeal virosphere and shed light on questions concerning the origin and evolution of viruses and cells. In this review, we summarize the current knowledge of archeoviruses, their interaction with hosts and plasmids and their role in the evolution of life.
Collapse
Affiliation(s)
- Mery Pina
- Institut Pasteur, Molecular Biology of the Gene in Extremophiles Unit, Paris, France
| | | | | | | |
Collapse
|
42
|
Gonnet M, Erauso G, Prieur D, Le Romancer M. pAMT11, a novel plasmid isolated from a Thermococcus sp. strain closely related to the virus-like integrated element TKV1 of the Thermococcus kodakaraensis genome. Res Microbiol 2010; 162:132-43. [PMID: 21144896 DOI: 10.1016/j.resmic.2010.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Accepted: 10/05/2010] [Indexed: 10/18/2022]
Abstract
A novel extrachromosomal element that we called pAMT11 was discovered in a deep-sea vent isolate belonging to the hyperthermophilic euryarchaeal order Thermococcales. It consists of a double-stranded DNA of 20,534bp which encodes 30 putative open reading frames (ORFs) of which six could be assigned to a putative function on the basis of sequence similarity to known genes or to protein domain families. Most of the ORFs of pAMT1 showed homology and synteny with a genomic island of Thermococcus kodakaraensis KOD1. This region, named TKV1, was previously described as a "virus-like integrated element" and assumed to integrate into the host chromosome by a site-specific recombination mechanism similar to that of Sulfolobus solfataricus virus 1. While most of the genes shared by pAMT11 and TKV1 encode putative membrane proteins presumably involved in virus particle formation, attempts to induce production of virus particles by mitomycin treatment of AMT11 cultures failed, suggesting that pAMT11 may represent the genome of a defective virus or a plasmid. Genomes of mobile elements usually contain two regions: a core of conserved genes mainly involved in replication, maintenance or spreading of the genetic element, and a variable set of accessory genes. Surprisingly, genes presumably implied in the replication process are quite divergent between TKV1 and pAMT11. Indeed, TKV1 possesses a MCM-like protein that may function as a replication initiator, while pAMT11 encodes a putative non-conventional protein distantly related to the Rep protein previously described in a small plasmid of Pyrococcus sp. strain JT1, assumed to replicate by a rolling-circle (RC) mechanism. However, in the case of pAMT11, this mode of plasmid replication could not be experimentally proven and is questionable given the lack of significant similarities with any other members of the RC-Rep superfamily and its unusual large size compared to other RC plasmids.
Collapse
Affiliation(s)
- Mathieu Gonnet
- Unité d'Epidémiologie Animale, UR356, INRA centre de Clermont-Ferrand Theix, Route de Theix, 63122 Saint Genès Champanelle, France.
| | | | | | | |
Collapse
|
43
|
|
44
|
Grant WD, Heaphy S. Metagenomics and recovery of enzyme genes from alkaline saline environments. ENVIRONMENTAL TECHNOLOGY 2010; 31:1135-1143. [PMID: 20718296 DOI: 10.1080/09593331003646661] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Enzymes functioning at alkaline pH are widely used in the detergent industry as additives to improve the stain removal properties of domestic and industrial cleaning products. This industry provides by far the major mass market for enzymes. With constantly changing formulations in detergents and concerns over energy demands, new and improved enzymes are constantly in demand. Soda lakes host dense populations of alkali-loving microbes and, as such, provide vast reservoirs of potentially useful enzymes for such an industry. Traditional recovery methods for new enzymes have involved the isolation of microbes, preferably from a compatible chemical environment such as a soda lake, followed by screening of the isolates for useful enzymic activity. At least two commercially significant enzymes originating from soda lake microbes have been marketed following this route. However, the failure to cultivate more than a small percentage of microbes from most environments necessarily markedly reduces the recovery of new enzymes. In recent years, interest has focussed on more comprehensive recovery methods based around detecting appropriate enzyme genes in nucleic acids extracted from potentially useful sites, thus maximizing coverage of the whole genetic resource in a particular biotope. Here we review progress to date in soda lake biotopes and discuss ways the field may develop in the future.
Collapse
Affiliation(s)
- William D Grant
- Department of Infection, Immunity and Inflammation, The University of Leicester, Leicester LE1 9HN, UK.
| | | |
Collapse
|
45
|
Sime-Ngando T, Lucas S, Robin A, Tucker KP, Colombet J, Bettarel Y, Desmond E, Gribaldo S, Forterre P, Breitbart M, Prangishvili D. Diversity of virus-host systems in hypersaline Lake Retba, Senegal. Environ Microbiol 2010; 13:1956-72. [PMID: 20738373 DOI: 10.1111/j.1462-2920.2010.02323.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Remarkable morphological diversity of virus-like particles was observed by transmission electron microscopy in a hypersaline water sample from Lake Retba, Senegal. The majority of particles morphologically resembled hyperthermophilic archaeal DNA viruses isolated from extreme geothermal environments. Some hypersaline viral morphotypes have not been previously observed in nature, and less than 1% of observed particles had a head-and-tail morphology, which is typical for bacterial DNA viruses. Culture-independent analysis of the microbial diversity in the sample suggested the dominance of extremely halophilic archaea. Few of the 16S sequences corresponded to known archeal genera (Haloquadratum, Halorubrum and Natronomonas), whereas the majority represented novel archaeal clades. Three sequences corresponded to a new basal lineage of the haloarchaea. Bacteria belonged to four major phyla, consistent with the known diversity in saline environments. Metagenomic sequencing of DNA from the purified virus-like particles revealed very few similarities to the NCBI non-redundant database at either the nucleotide or amino acid level. Some of the identifiable virus sequences were most similar to previously described haloarchaeal viruses, but no sequence similarities were found to archaeal viruses from extreme geothermal environments. A large proportion of the sequences had similarity to previously sequenced viral metagenomes from solar salterns.
Collapse
Affiliation(s)
- Télesphore Sime-Ngando
- Laboratoire Microorganismes: Génome et Environnement, Université Blaise Pascal (Clermont-Ferrand II), UMR CNRS 6023, F-63177, Aubière Cedex, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Krupovic M, Gribaldo S, Bamford DH, Forterre P. The evolutionary history of archaeal MCM helicases: a case study of vertical evolution combined with hitchhiking of mobile genetic elements. Mol Biol Evol 2010; 27:2716-32. [PMID: 20581330 DOI: 10.1093/molbev/msq161] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Genes encoding DNA replication proteins have been frequently exchanged between cells and mobile elements, such as viruses or plasmids. This raises potential problems to reconstruct their history. Here, we combine phylogenetic and genomic context analyses to study the evolution of the replicative minichromosome maintenance (MCM) helicases in Archaea. Several archaeal genomes encode more than one copy of the mcm gene. Genome context analysis reveals that most of these additional copies are encoded within mobile elements. Exhaustive analysis of these elements reveals diverse groups of integrated archaeal plasmids or viruses, including several head-and-tail proviruses. Some MCMs encoded by mobile elements are structurally distinct from their cellular counterparts, with one case of novel domain organization. Both genome context and phylogenetic analysis indicate that MCM encoded by mobile elements were recruited from cellular genomes. An accelerated evolution and a dramatic expansion of methanococcal MCMs suggest a host-to-virus-to-host transfer loop, possibly triggered by the loss of the archaeal initiator protein Cdc6 in Methanococcales. Surprisingly, despite extensive transfer of mcm genes between viruses, plasmids, and cells, the topology of the MCM tree is strikingly congruent with the consensus archaeal phylogeny, indicating that mobile elements encoding mcm have coevolved with their hosts and that DNA replication proteins can be also useful to reconstruct the history of the archaeal domain.
Collapse
Affiliation(s)
- Mart Krupovic
- Department of Biosciences and Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | | | | | | |
Collapse
|
47
|
Krupovič M, Forterre P, Bamford DH. Comparative Analysis of the Mosaic Genomes of Tailed Archaeal Viruses and Proviruses Suggests Common Themes for Virion Architecture and Assembly with Tailed Viruses of Bacteria. J Mol Biol 2010; 397:144-60. [DOI: 10.1016/j.jmb.2010.01.037] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 01/12/2010] [Accepted: 01/19/2010] [Indexed: 10/19/2022]
|
48
|
Particle assembly and ultrastructural features associated with replication of the lytic archaeal virus sulfolobus turreted icosahedral virus. J Virol 2009; 83:5964-70. [PMID: 19357174 DOI: 10.1128/jvi.02668-08] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Little is known about the replication cycle of archaeal viruses. We have investigated the ultrastructural changes of Sulfolobus solfataricus P2 associated with infection by Sulfolobus turreted icosahedral virus (STIV). A time course of a near synchronous STIV infection was analyzed using both scanning and transmission electron microscopy. Assembly of STIV particles, including particles lacking DNA, was observed within cells, and fully assembled STIV particles were visible by 30 h postinfection (hpi). STIV was determined to be a lytic virus, causing cell disruption beginning at 30 hpi. Prior to cell lysis, virus infection resulted in the formation of pyramid-like projections from the cell surface. These projections, which have not been documented in any other host-virus system, appeared to be caused by the protrusion of the cell membrane beyond the bordering S-layer. These structures are thought to be sites at which progeny virus particles are released from infected cells. Based on these observations of lysis, a plaque assay was developed for STIV. From these studies we propose an overall assembly model for STIV.
Collapse
|
49
|
Pietilä MK, Roine E, Paulin L, Kalkkinen N, Bamford DH. An ssDNA virus infecting archaea: a new lineage of viruses with a membrane envelope. Mol Microbiol 2009; 72:307-19. [PMID: 19298373 DOI: 10.1111/j.1365-2958.2009.06642.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Archaeal organisms are generally known as diverse extremophiles, but they play a crucial role also in moderate environments. So far, only about 50 archaeal viruses have been described in some detail. Despite this, unusual viral morphotypes within this group have been reported. Interestingly, all isolated archaeal viruses have a double-stranded DNA (dsDNA) genome. To further characterize the diversity of archaeal viruses, we screened highly saline water samples for archaea and their viruses. Here, we describe a new haloarchaeal virus, Halorubrum pleomorphic virus 1 (HRPV-1) that was isolated from a solar saltern and infects an indigenous host belonging to the genus Halorubrum. Infection does not cause cell lysis, but slightly retards growth of the host and results in high replication of the virus. The sequenced genome (7048 nucleotides) of HRPV-1 is single-stranded DNA (ssDNA), which makes HRPV-1 the first characterized archaeal virus that does not have a dsDNA genome. In spite of this, similarities to another archaeal virus were observed. Two major structural proteins were recognized in protein analyses, and by lipid analyses it was shown that the virion contains a membrane. Electron microscopy studies indicate that the enveloped virion is pleomorphic (approximately 44 x 55 nm). HRPV-1 virion may represent commonly used virion architecture, and it seems that structure-based virus lineages may be extended to non-icosahedral viruses.
Collapse
Affiliation(s)
- Maija K Pietilä
- Institute of Biotechnology and Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | | | | | | | | |
Collapse
|
50
|
Porter K, Dyall-Smith ML. Transfection of haloarchaea by the DNAs of spindle and round haloviruses and the use of transposon mutagenesis to identify non-essential regions. Mol Microbiol 2009; 70:1236-45. [PMID: 19006816 DOI: 10.1111/j.1365-2958.2008.06478.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Spindle-shaped halovirus His2 and spherical halovirus SH1 represent ecologically dominant virus morphotypes in high-salt environments. Both have linear dsDNA genomes with inverted terminal repeat sequences and terminal proteins, and probably replicate using protein priming. As a first step towards conventional genetic analyses on these viruses, we show that purified viral DNAs can transfect host cells. Intact terminal proteins were essential for this process. Despite the narrow host ranges of these viruses, at least under laboratory conditions, their DNAs were able to transfect a wide range of haloarchaeal species, demonstrating that the cytoplasms of diverse haloarchaea possess all the factors necessary for viral DNA synthesis and virion assembly. Transposon mutagenesis of viral DNAs was then used in conjunction with transfection to produce recombinant viruses, and to then map the insertion sites to identify non-essential genes. The inserts in 34 His2 mutants were mapped precisely, and most clustered in a few, specific regions, particularly in the inverted terminal repeats and near the ends of ORFs. The results are consistent with the small genome size and densely packed, often overlapping ORFs that are transcribed as long operons. This study is the first demonstration of transfection and transposon mutagenesis in protein-primed archaeal viruses.
Collapse
Affiliation(s)
- Kate Porter
- Biota Holdings Ltd., 10/585 Blackburn Road, Notting Hill, Victoria 3168, Australia
| | | |
Collapse
|