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Brodersen KE, Mosshammer M, Bittner MJ, Hallstrøm S, Santner J, Riemann L, Kühl M. Seagrass-mediated rhizosphere redox gradients are linked with ammonium accumulation driven by diazotrophs. Microbiol Spectr 2024; 12:e0333523. [PMID: 38426746 DOI: 10.1128/spectrum.03335-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 01/24/2024] [Indexed: 03/02/2024] Open
Abstract
Seagrasses can enhance nutrient mobilization in their rhizosphere via complex interactions with sediment redox conditions and microbial populations. Yet, limited knowledge exists on how seagrass-derived rhizosphere dynamics affect nitrogen cycling. Using optode and gel-sampler-based chemical imaging, we show that radial O2 loss (ROL) from rhizomes and roots leads to the formation of redox gradients around below-ground tissues of seagrass (Zostera marina), which are co-localized with regions of high ammonium concentrations in the rhizosphere. Combining such chemical imaging with fine-scale sampling for microbial community and gene expression analyses indicated that multiple biogeochemical pathways and microbial players can lead to high ammonium concentration within the oxidized regions of the seagrass rhizosphere. Symbiotic N2-fixing bacteria (Bradyrhizobium) were particularly abundant and expressed the diazotroph functional marker gene nifH in Z. marina rhizosphere areas with high ammonium concentrations. Such an association between Z. marina and Bradyrhizobium can facilitate ammonium mobilization, the preferred nitrogen source for seagrasses, enhancing seagrass productivity within nitrogen-limited environments. ROL also caused strong gradients of sulfide at anoxic/oxic interfaces in rhizosphere areas, where we found enhanced nifH transcription by sulfate-reducing bacteria. Furthermore, we found a high abundance of methylotrophic and sulfide-oxidizing bacteria in rhizosphere areas, where O2 was released from seagrass rhizomes and roots. These bacteria could play a beneficial role for the plants in terms of their methane and sulfide oxidation, as well as their formation of growth factors and phytohormones. ROL from below-ground tissues of seagrass, thus, seems crucial for ammonium production in the rhizosphere via stimulation of multiple diazotrophic associations. IMPORTANCE Seagrasses are important marine habitats providing several ecosystem services in coastal waters worldwide, such as enhancing marine biodiversity and mitigating climate change through efficient carbon sequestration. Notably, the fitness of seagrasses is affected by plant-microbe interactions. However, these microscale interactions are challenging to study and large knowledge gaps prevail. Our study shows that redox microgradients in the rhizosphere of seagrass select for a unique microbial community that can enhance the ammonium availability for seagrass. We provide first experimental evidence that Rhizobia, including the symbiotic N2-fixing bacteria Bradyrhizobium, can contribute to the bacterial ammonium production in the seagrass rhizosphere. The release of O2 from rhizomes and roots also caused gradients of sulfide in rhizosphere areas with enhanced nifH transcription by sulfate-reducing bacteria. O2 release from seagrass root systems thus seems crucial for ammonium production in the rhizosphere via stimulation of multiple diazotrophic associations.
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Affiliation(s)
| | - Maria Mosshammer
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Meriel J Bittner
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Søren Hallstrøm
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Jakob Santner
- Department of Crop Sciences, Institute of Agronomy, University of Natural Resources and Life Sciences Vienna, Tulln an der Donau, Austria
| | - Lasse Riemann
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
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Pedersen TR, Wessman M, Lindegaard M, Hallstrøm S, Westergaard C, Brock I, Dzajic E, Holmgaard DB, Jensen CS, Justesen US, Kornum JB, Søndergaard TS, Thomsen MK, Westh H, Østergaard C, Hoffmann S, Stegger M. Gonorrhoea on the rise in Denmark since 2022: distinct clones drive increase in heterosexual individuals. Euro Surveill 2024; 29:2400059. [PMID: 38362625 PMCID: PMC10986658 DOI: 10.2807/1560-7917.es.2024.29.7.2400059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 02/14/2024] [Indexed: 02/17/2024] Open
Abstract
A surge in gonorrhoea in Denmark has occurred since 2022, a 46% increase from 2021. National surveillance, leveraging mandatory reporting and epidemiological data, highlights three distinct clades linked to heterosexual transmission. Despite the rise, these exhibit high susceptibility, contrasting MSM-associated strains. Geographical hotspots and age-specific patterns further illuminate transmission dynamics. The combination of genomic and epidemiological data provides novel insights into the evolving landscape of gonorrhoea, indicating potential shifts in infection dynamics and transmissibility.
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Affiliation(s)
- Thomas Roland Pedersen
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Maria Wessman
- Department of Infectious Disease Epidemiology and Prevention, Statens Serum Institut, Copenhagen, Denmark
| | - Mikkel Lindegaard
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Søren Hallstrøm
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Casper Westergaard
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Inger Brock
- Department of Clinical Microbiology, Herlev and Gentofte Hospital, Herlev, Denmark
| | - Esad Dzajic
- Clinical Diagnostic Department, University Hospital of Southern Denmark, Esbjerg, Denmark
| | | | - Christian Salgård Jensen
- Department of Clinical Microbiology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Ulrik Stenz Justesen
- Department of Clinical Microbiology, Odense University Hospital, Odense, Denmark
| | | | | | - Marianne Kragh Thomsen
- Department of Clinical Microbiology, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Henrik Westh
- Department of Clinical Microbiology, Copenhagen University Hospital, Hvidovre, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Claus Østergaard
- Department of Clinical Microbiology, University Hospital of Southern Denmark, Vejle, Denmark
| | - Steen Hoffmann
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Marc Stegger
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
- Antimicrobial Resistance and Infectious Diseases Laboratory, Harry Butler Institute, Murdoch University, Perth, Australia
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Fernández-Juárez V, Hallstrøm S, Pacherres CO, Wang J, Coll-Garcia G, Kühl M, Riemann L. Biofilm formation and cell plasticity drive diazotrophy in an anoxygenic phototrophic bacterium. Appl Environ Microbiol 2023; 89:e0102723. [PMID: 37882569 PMCID: PMC10686084 DOI: 10.1128/aem.01027-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 09/14/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE The contribution of non-cyanobacterial diazotrophs (NCDs) to total N2 fixation in the marine water column is unknown, but their importance is likely constrained by the limited availability of dissolved organic matter and low O2 conditions. Light could support N2 fixation and growth by NCDs, yet no examples from bacterioplankton exist. In this study, we show that the phototrophic NCD, Rhodopseudomonas sp. BAL398, which is a member of the diazotrophic community in the surface waters of the Baltic Sea, can utilize light. Our study highlights the significance of biofilm formation for utilizing light and fixing N2 under oxic conditions and the role of cell plasticity in regulating these processes. Our findings have implications for the general understanding of the ecology and importance of NCDs in marine waters.
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Affiliation(s)
- Víctor Fernández-Juárez
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Søren Hallstrøm
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Cesar O. Pacherres
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jiaqi Wang
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Guillem Coll-Garcia
- Microbiology, Biology Department, University of the Balearic Islands, Palma de Mallorca, Spain
- Environmental Microbiology Group, Mediterranean Institute for Advanced Studies (CSIC-UIB), Esporles, Spain
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Lasse Riemann
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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Johannesen TB, Munkstrup C, Edslev SM, Baig S, Nielsen S, Funk T, Kristensen DK, Jacobsen LH, Ravn SF, Bindslev N, Gubbels S, Voldstedlund M, Jokelainen P, Hallstrøm S, Rasmussen A, Kristinsson KG, Fuglsang-Damgaard D, Dessau RB, Olsén AB, Jensen CS, Skovby A, Ellermann-Eriksen S, Jensen TG, Dzajic E, Østergaard C, Lomborg Andersen S, Hoffmann S, Andersen PH, Stegger M. Increase in invasive group A streptococcal infections and emergence of novel, rapidly expanding sub-lineage of the virulent Streptococcus pyogenes M1 clone, Denmark, 2023. Euro Surveill 2023; 28:2300291. [PMID: 37382884 PMCID: PMC10311951 DOI: 10.2807/1560-7917.es.2023.28.26.2300291] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 06/29/2023] [Indexed: 06/30/2023] Open
Abstract
A highly virulent sub-lineage of the Streptococcus pyogenes M1 clone has been rapidly expanding throughout Denmark since late 2022 and now accounts for 30% of the new invasive group A streptococcal infections. We aimed to investigate whether a shift in variant composition can account for the high incidence rates observed over winter 2022/23, or if these are better explained by the impact of COVID-19-related restrictions on population immunity and carriage of group A Streptococcus.
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Affiliation(s)
| | - Charlotte Munkstrup
- Infectious Disease Epidemiology and Prevention, Statens Serum Institut, Copenhagen, Denmark
| | - Sofie Marie Edslev
- Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Sharmin Baig
- Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Stine Nielsen
- Infectious Disease Epidemiology and Prevention, Statens Serum Institut, Copenhagen, Denmark
| | - Tjede Funk
- Infectious Disease Epidemiology and Prevention, Statens Serum Institut, Copenhagen, Denmark
| | | | | | - Signe Fischer Ravn
- Data Integration and Analysis, Statens Serum Institut, Copenhagen, Denmark
| | - Niels Bindslev
- Data Integration and Analysis, Statens Serum Institut, Copenhagen, Denmark
| | - Sophie Gubbels
- Data Integration and Analysis, Statens Serum Institut, Copenhagen, Denmark
| | | | - Pikka Jokelainen
- Infectious Disease Preparedness, Statens Serum Institut, Copenhagen, Denmark
| | - Søren Hallstrøm
- Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Astrid Rasmussen
- Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Karl Gústaf Kristinsson
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- Department of Clinical Microbiology, Landspitali - the National University Hospital, Reykjavik, Iceland
| | | | - Ram B Dessau
- Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
- Department of Clinical Microbiology, Zealand University Hospital, Slagelse, Denmark
| | - Agnieszka Barbara Olsén
- Department of Clinical Microbiology, Herlev and Gentofte Hospital - University Hospital, Herlev, Denmark
| | | | - Annette Skovby
- Copenhagen University Hospital - Amager and Hvidovre, Hvidovre, Denmark
| | | | - Thøger Gorm Jensen
- Department of Clinical Microbiology, Odense University Hospital and Research Unit of Clinical Microbiology, Odense, Denmark
| | - Esad Dzajic
- Clinical Diagnostic Department, Clinical Microbiology, Hospital South West Jutland, University Hospital of Southern Denmark, Esbjerg, Denmark
| | - Claus Østergaard
- Department of Clinical Microbiology, Lillebælt Hospital, University Hospital of Southern Denmark, Vejle, Denmark
| | - Steen Lomborg Andersen
- Department of Clinical Microbiology, Sønderjylland Hospital, University Hospital of Southern Denmark, Aabenraa, Denmark
| | - Steen Hoffmann
- Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Peter Henrik Andersen
- Infectious Disease Epidemiology and Prevention, Statens Serum Institut, Copenhagen, Denmark
| | - Marc Stegger
- Antimicrobial Resistance and Infectious Diseases Laboratory, Harry Butler Institute, Murdoch University, Perth, Australia
- Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
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Hallstrøm S, Raina JB, Ostrowski M, Parks DH, Tyson GW, Hugenholtz P, Stocker R, Seymour JR, Riemann L. Chemotaxis may assist marine heterotrophic bacterial diazotrophs to find microzones suitable for N 2 fixation in the pelagic ocean. ISME J 2022; 16:2525-2534. [PMID: 35915168 PMCID: PMC9561647 DOI: 10.1038/s41396-022-01299-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 06/05/2023]
Abstract
Heterotrophic bacterial diazotrophs (HBDs) are ubiquitous in the pelagic ocean, where they have been predicted to carry out the anaerobic process of nitrogen fixation within low-oxygen microenvironments associated with marine pelagic particles. However, the mechanisms enabling particle colonization by HBDs are unknown. We hypothesized that HBDs use chemotaxis to locate and colonize suitable microenvironments, and showed that a cultivated marine HBD is chemotactic toward amino acids and phytoplankton-derived DOM. Using an in situ chemotaxis assay, we also discovered that diverse HBDs at a coastal site are motile and chemotactic toward DOM from various phytoplankton taxa and, indeed, that the proportion of diazotrophs was up to seven times higher among the motile fraction of the bacterial community compared to the bulk seawater community. Finally, three of four HBD isolates and 16 of 17 HBD metagenome assembled genomes, recovered from major ocean basins and locations along the Australian coast, each encoded >85% of proteins affiliated with the bacterial chemotaxis pathway. These results document the widespread capacity for chemotaxis in diverse and globally relevant marine HBDs. We suggest that HBDs could use chemotaxis to seek out and colonize low-oxygen microenvironments suitable for nitrogen fixation, such as those formed on marine particles. Chemotaxis in HBDs could therefore affect marine nitrogen and carbon biogeochemistry by facilitating nitrogen fixation within otherwise oxic waters, while also altering particle degradation and the efficiency of the biological pump.
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Affiliation(s)
- Søren Hallstrøm
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Jean-Baptiste Raina
- Climate Change Cluster, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
| | - Martin Ostrowski
- Climate Change Cluster, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
| | - Donovan H Parks
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD, Australia
| | - Gene W Tyson
- Centre for Microbiome Research, School of Biomedical Science, Translational Research Institute, Queensland University of Technology, Woolloongabba, QLD, Australia
| | - Philip Hugenholtz
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD, Australia
| | - Roman Stocker
- Institute of Environmental Engineering, Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zurich, Switzerland
| | - Justin R Seymour
- Climate Change Cluster, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
| | - Lasse Riemann
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark.
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6
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Benavides M, Bonnet S, Le Moigne FAC, Armin G, Inomura K, Hallstrøm S, Riemann L, Berman-Frank I, Poletti E, Garel M, Grosso O, Leblanc K, Guigue C, Tedetti M, Dupouy C. Sinking Trichodesmium fixes nitrogen in the dark ocean. ISME J 2022; 16:2398-2405. [PMID: 35835942 PMCID: PMC9478103 DOI: 10.1038/s41396-022-01289-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/29/2022] [Accepted: 07/05/2022] [Indexed: 01/04/2023]
Abstract
The photosynthetic cyanobacterium Trichodesmium is widely distributed in the surface low latitude ocean where it contributes significantly to N2 fixation and primary productivity. Previous studies found nifH genes and intact Trichodesmium colonies in the sunlight-deprived meso- and bathypelagic layers of the ocean (200-4000 m depth). Yet, the ability of Trichodesmium to fix N2 in the dark ocean has not been explored. We performed 15N2 incubations in sediment traps at 170, 270 and 1000 m at two locations in the South Pacific. Sinking Trichodesmium colonies fixed N2 at similar rates than previously observed in the surface ocean (36-214 fmol N cell-1 d-1). This activity accounted for 40 ± 28% of the bulk N2 fixation rates measured in the traps, indicating that other diazotrophs were also active in the mesopelagic zone. Accordingly, cDNA nifH amplicon sequencing revealed that while Trichodesmium accounted for most of the expressed nifH genes in the traps, other diazotrophs such as Chlorobium and Deltaproteobacteria were also active. Laboratory experiments simulating mesopelagic conditions confirmed that increasing hydrostatic pressure and decreasing temperature reduced but did not completely inhibit N2 fixation in Trichodesmium. Finally, using a cell metabolism model we predict that Trichodesmium uses photosynthesis-derived stored carbon to sustain N2 fixation while sinking into the mesopelagic. We conclude that sinking Trichodesmium provides ammonium, dissolved organic matter and biomass to mesopelagic prokaryotes.
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Affiliation(s)
- Mar Benavides
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France.
- Turing Center for Living Systems, Aix-Marseille University, 13009, Marseille, France.
| | - Sophie Bonnet
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Frédéric A C Le Moigne
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
- LEMAR, Laboratoire des Sciences de l'Environnement Marin, UMR6539, CNRS, UBO, IFREMER, IRD, 29280, Plouzané, Technopôle Brest-Iroise, France
| | - Gabrielle Armin
- Graduate School of Oceanography, University of Rhode Island, South Kingstown, RI, USA
| | - Keisuke Inomura
- Graduate School of Oceanography, University of Rhode Island, South Kingstown, RI, USA
| | - Søren Hallstrøm
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Lasse Riemann
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Ilana Berman-Frank
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Mt, Carmel, Haifa, Israel
| | - Emilie Poletti
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Marc Garel
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Olivier Grosso
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Karine Leblanc
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Catherine Guigue
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Marc Tedetti
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Cécile Dupouy
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
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7
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Han W, Li Y, Deng L, Feng M, Peng W, Hallstrøm S, Zhang J, Peng N, Liang YX, White MF, She Q. A type III-B CRISPR-Cas effector complex mediating massive target DNA destruction. Nucleic Acids Res 2017; 45:1983-1993. [PMID: 27986854 PMCID: PMC5389615 DOI: 10.1093/nar/gkw1274] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 12/07/2016] [Indexed: 12/26/2022] Open
Abstract
The CRISPR (clustered regularly interspaced short palindromic repeats) system protects archaea and bacteria by eliminating nucleic acid invaders in a crRNA-guided manner. The Sulfolobus islandicus type III-B Cmr–α system targets invading nucleic acid at both RNA and DNA levels and DNA targeting relies on the directional transcription of the protospacer in vivo. To gain further insight into the involved mechanism, we purified a native effector complex of III-B Cmr–α from S. islandicus and characterized it in vitro. Cmr–α cleaved RNAs complementary to crRNA present in the complex and its ssDNA destruction activity was activated by target RNA. The ssDNA cleavage required mismatches between the 5΄-tag of crRNA and the 3΄-flanking region of target RNA. An invader plasmid assay showed that mutation either in the histidine-aspartate acid (HD) domain (a quadruple mutation) or in the GGDD motif of the Cmr–2α protein resulted in attenuation of the DNA interference in vivo. However, double mutation of the HD motif only abolished the DNase activity in vitro. Furthermore, the activated Cmr–α binary complex functioned as a highly active DNase to destroy a large excess DNA substrate, which could provide a powerful means to rapidly degrade replicating viral DNA.
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Affiliation(s)
- Wenyuan Han
- Archaea Centre, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, Copenhagen Biocenter, DK-2200 Copenhagen N, Denmark
| | - Yingjun Li
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
| | - Ling Deng
- Archaea Centre, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, Copenhagen Biocenter, DK-2200 Copenhagen N, Denmark
| | - Mingxia Feng
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
| | - Wenfang Peng
- Archaea Centre, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, Copenhagen Biocenter, DK-2200 Copenhagen N, Denmark
| | - Søren Hallstrøm
- Archaea Centre, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, Copenhagen Biocenter, DK-2200 Copenhagen N, Denmark
| | - Jing Zhang
- Biomedical Sciences Research Complex, University of St Andrews, Fife KY16 9ST, UK
| | - Nan Peng
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
| | - Yun Xiang Liang
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
| | - Malcolm F White
- Biomedical Sciences Research Complex, University of St Andrews, Fife KY16 9ST, UK
| | - Qunxin She
- Archaea Centre, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, Copenhagen Biocenter, DK-2200 Copenhagen N, Denmark.,State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, 430070 Wuhan, China
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8
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Peng W, Li H, Hallstrøm S, Peng N, Liang YX, She Q. Genetic determinants of PAM-dependent DNA targeting and pre-crRNA processing in Sulfolobus islandicus. RNA Biol 2013; 10:738-48. [PMID: 23392249 PMCID: PMC3737332 DOI: 10.4161/rna.23798] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Bacteria and Archaea encode clustered, regularly interspaced, short palindromic repeat (CRISPR) systems to confer adaptive immunity to invasive viruses and plasmids. Recent studies of CRISPR systems revealed that diverse CRISPR-associated (Cas) interference modules often coexist in different organisms but functions of cas genes have not been dissected in any of these systems. The crenarchaeon Sulfolobus islandicus encodes three distinct CRISPR interference modules, including a type IA system and two type IIIB systems: Cmr-α and Cmr-β. To study the genetic determinants of protospacer-adjacent motif (PAM)-dependent DNA targeting activity and mature CRISPR RNA (crRNA) production in this organism, mutants deleting individual genes of the type IA system or removing each of other Cas modules were constructed. Characterization of these mutants revealed that Cas7, Cas5, Cas6, Cas3′ and Cas3” are essential for PAM-dependent DNA targeting activity, whereas Csa5, along with all other Cas modules, is dispensable for the targeting in the crenarchaeon. Cas6 is implicated as the only enzyme for pre-crRNA processing and the crRNA maturation is independent of the DNA targeting activity. Importantly, we show that Cas7 and Cas5 are essential for stabilizing the processing intermediates and mature crRNAs, respectively, and that depleting the helicase or nuclease domain of Cas3 leads to the accumulation of processing intermediates. This demonstrates that in addition to Cas6, other Cas proteins of an archaeal type IA system also contribute to crRNA processing.
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Affiliation(s)
- Wenfang Peng
- State Key Laboratory of Agricultural Microbiology and College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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