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Ionescu D, Volland JM, Contarini PE, Gros O. Genomic Mysteries of Giant Bacteria: Insights and Implications. Genome Biol Evol 2023; 15:evad163. [PMID: 37708391 PMCID: PMC10519445 DOI: 10.1093/gbe/evad163] [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: 03/27/2023] [Revised: 08/18/2023] [Accepted: 09/01/2023] [Indexed: 09/16/2023] Open
Abstract
Bacteria and Archaea are traditionally regarded as organisms with a simple morphology constrained to a size of 2-3 µm. Nevertheless, the history of microbial research is rich in the description of giant bacteria exceeding tens and even hundreds of micrometers in length or diameter already from its early days, for example, Beggiatoa spp., to the present, for example, Candidatus Thiomargarita magnifica. While some of these giants are still being studied, some were lost to science, with merely drawings and photomicrographs as evidence for their existence. The physiology and biogeochemical role of giant bacteria have been studied, with a large focus on those involved in the sulfur cycle. With the onset of the genomic era, no special emphasis has been given to this group, in an attempt to gain a novel, evolutionary, and molecular understanding of the phenomenon of bacterial gigantism. The few existing genomic studies reveal a mysterious world of hyperpolyploid bacteria with hundreds to hundreds of thousands of chromosomes that are, in some cases, identical and in others, extremely different. These studies on giant bacteria reveal novel organelles, cellular compartmentalization, and novel mechanisms to combat the accumulation of deleterious mutations in polyploid bacteria. In this perspective paper, we provide a brief overview of what is known about the genomics of giant bacteria and build on that to highlight a few burning questions that await to be addressed.
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Affiliation(s)
- Danny Ionescu
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Neuglobsow, Germany
| | - Jean-Marie Volland
- Laboratory for Research in Complex Systems, Menlo Park, California, USA
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Paul-Emile Contarini
- Laboratory for Research in Complex Systems, Menlo Park, California, USA
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d’Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Pointe-à-Pitre, France
| | - Olivier Gros
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d’Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Pointe-à-Pitre, France
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Santer M, Kupczok A, Dagan T, Uecker H. Fixation dynamics of beneficial alleles in prokaryotic polyploid chromosomes and plasmids. Genetics 2022; 222:6663764. [PMID: 35959975 PMCID: PMC9526072 DOI: 10.1093/genetics/iyac121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 07/20/2022] [Indexed: 11/15/2022] Open
Abstract
Theoretical population genetics has been mostly developed for sexually reproducing diploid and for monoploid (haploid) organisms, focusing on eukaryotes. The evolution of bacteria and archaea is often studied by models for the allele dynamics in monoploid populations. However, many prokaryotic organisms harbor multicopy replicons—chromosomes and plasmids—and theory for the allele dynamics in populations of polyploid prokaryotes remains lacking. Here, we present a population genetics model for replicons with multiple copies in the cell. Using this model, we characterize the fixation process of a dominant beneficial mutation at 2 levels: the phenotype and the genotype. Our results show that depending on the mode of replication and segregation, the fixation of the mutant phenotype may precede genotypic fixation by many generations; we term this time interval the heterozygosity window. We furthermore derive concise analytical expressions for the occurrence and length of the heterozygosity window, showing that it emerges if the copy number is high and selection strong. Within the heterozygosity window, the population is phenotypically adapted, while both alleles persist in the population. Replicon ploidy thus allows for the maintenance of genetic variation following phenotypic adaptation and consequently for reversibility in adaptation to fluctuating environmental conditions.
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Affiliation(s)
- Mario Santer
- Research group Stochastic Evolutionary Dynamics, Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
| | - Anne Kupczok
- Institute of General Microbiology, Kiel University, 24118 Kiel, Germany.,Bioinformatics group, Department of Plant Sciences, Wageningen University & Research, 6708PB Wageningen, Netherlands
| | - Tal Dagan
- Institute of General Microbiology, Kiel University, 24118 Kiel, Germany
| | - Hildegard Uecker
- Research group Stochastic Evolutionary Dynamics, Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
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Genomic attributes of thermophilic and hyperthermophilic bacteria and archaea. World J Microbiol Biotechnol 2022; 38:135. [PMID: 35695998 DOI: 10.1007/s11274-022-03327-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/31/2022] [Indexed: 10/18/2022]
Abstract
Thermophiles and hyperthermophiles are immensely useful in understanding the evolution of life, besides their utility in environmental and industrial biotechnology. Advancements in sequencing technologies have revolutionized the field of microbial genomics. The massive generation of data enhances the sequencing coverage multi-fold and allows to analyse the entire genomic features of microbes efficiently and accurately. The mandate of a pure isolate can also be bypassed where whole metagenome-assembled genomes and single cell-based sequencing have fulfilled the majority of the criteria to decode various attributes of microbial genomes. A boom has, therefore, been seen in analysing the extremophilic bacteria and archaea using sequence-based approaches. Due to extensive sequence analysis, it becomes easier to understand the gene flow and their evolution among the members of bacteria and archaea. For instance, sequencing unveiled that Thermotoga maritima shares around 24% of genes of archaeal origin. Comparative and functional genomics provide an analytical view to understanding the microbial diversity of thermophilic bacteria and archaea, their interactions with other microbes, their adaptations, gene flow, and evolution over time. In this review, the genomic features of thermophilic bacteria and archaea are dealt with comprehensively.
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Ionescu D, Zoccarato L, Zaduryan A, Schorn S, Bizic M, Pinnow S, Cypionka H, Grossart HP. Heterozygous, Polyploid, Giant Bacterium, Achromatium, Possesses an Identical Functional Inventory Worldwide across Drastically Different Ecosystems. Mol Biol Evol 2021; 38:1040-1059. [PMID: 33169788 PMCID: PMC7947748 DOI: 10.1093/molbev/msaa273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Achromatium is large, hyperpolyploid and the only known heterozygous bacterium. Single cells contain approximately 300 different chromosomes with allelic diversity far exceeding that typically harbored by single bacteria genera. Surveying all publicly available sediment sequence archives, we show that Achromatium is common worldwide, spanning temperature, salinity, pH, and depth ranges normally resulting in bacterial speciation. Although saline and freshwater Achromatium spp. appear phylogenetically separated, the genus Achromatium contains a globally identical, complete functional inventory regardless of habitat. Achromatium spp. cells from differing ecosystems (e.g., from freshwater to saline) are, unexpectedly, equally functionally equipped but differ in gene expression patterns by transcribing only relevant genes. We suggest that environmental adaptation occurs by increasing the copy number of relevant genes across the cell's hundreds of chromosomes, without losing irrelevant ones, thus maintaining the ability to survive in any ecosystem type. The functional versatility of Achromatium and its genomic features reveal alternative genetic and evolutionary mechanisms, expanding our understanding of the role and evolution of polyploidy in bacteria while challenging the bacterial species concept and drivers of bacterial speciation.
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Affiliation(s)
- Danny Ionescu
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Neuglobsow, Germany
- Berlin Brandenburg Institute of Biodiversity, Berlin, Germany
| | - Luca Zoccarato
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Neuglobsow, Germany
| | - Artur Zaduryan
- Department of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Sina Schorn
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Mina Bizic
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Neuglobsow, Germany
- Berlin Brandenburg Institute of Biodiversity, Berlin, Germany
| | - Solvig Pinnow
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Neuglobsow, Germany
| | - Heribert Cypionka
- Institute for Chemistry and Biology of the Marine Environment, Oldenburg, Germany
| | - Hans-Peter Grossart
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Neuglobsow, Germany
- Berlin Brandenburg Institute of Biodiversity, Berlin, Germany
- Institute of Biochemistry and Biology, Potsdam University, Potsdam, Germany
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Blesa A, Baquedano I, González-de la Fuente S, Mencía M, Berenguer J. Integrative and Conjugative Element ICETh1 Functions as a Pangenomic DNA Capture Module in Thermus thermophilus. Microorganisms 2020; 8:microorganisms8122051. [PMID: 33371442 PMCID: PMC7767461 DOI: 10.3390/microorganisms8122051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/18/2020] [Accepted: 12/18/2020] [Indexed: 11/16/2022] Open
Abstract
Transjugation is an unconventional conjugation mechanism in Thermus thermophilus (Tth) that involves the active participation of both mating partners, encompassing a DNA secretion system (DSS) in the donor and an active natural competence apparatus (NCA) in the recipient cells. DSS is encoded within an integrative and conjugative element (ICETh1) in the strain Tth HB27, whereas the NCA is constitutively expressed in both mates. Previous experiments suggested the presence of multiple origins of transfer along the genome, which could generate genomic mosaicity among the progeny. Here, we designed transjugation experiments between two closely related strains of Tth with highly syntenic genomes, containing enough single nucleotide polymorphisms to allow precise parenthood analysis. Individual clones from the progeny were sequenced, revealing their origin as derivatives of our ICETh1-containing intended “donor” strain (HB27), which had acquired separate fragments from the genome of the ICETh1-free HB8 cells, which are our intended recipient. Due to the bidirectional nature of transjugation, only assays employing competence-defective HB27 derivatives as donors allowed the recovery of HB8-derived progeny. These results show a preference for a retrotransfer mechanism in transjugation in ICETh1-bearing strains, supporting an inter-strain gene-capture function for ICETh1. This function could benefit the donor-capable host by facilitating the acquisition of adaptive traits from external sources, ultimately increasing the open pangenome of Thermus, maximizing the potential repertoire of physiological and phenotypical traits related to adaptation and speciation.
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Affiliation(s)
- Alba Blesa
- Department of Biotechnology, Faculty of Experimental Sciences, Universidad Francisco de Vitoria, 28223 Madrid, Spain
- Correspondence: (A.B.); (J.B.); Tel.: +34-91194498 (J.B.)
| | - Ignacio Baquedano
- Centro de Biología Molecular Severo Ochoa (CBMSO), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; (I.B.); (S.G.-d.l.F.); (M.M.)
| | - Sandra González-de la Fuente
- Centro de Biología Molecular Severo Ochoa (CBMSO), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; (I.B.); (S.G.-d.l.F.); (M.M.)
| | - Mario Mencía
- Centro de Biología Molecular Severo Ochoa (CBMSO), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; (I.B.); (S.G.-d.l.F.); (M.M.)
| | - José Berenguer
- Centro de Biología Molecular Severo Ochoa (CBMSO), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; (I.B.); (S.G.-d.l.F.); (M.M.)
- Correspondence: (A.B.); (J.B.); Tel.: +34-91194498 (J.B.)
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Li H, Gao T. MreB and MreC act as the geometric moderators of the cell wall synthetic machinery in Thermus thermophiles. Microbiol Res 2020; 243:126655. [PMID: 33279728 DOI: 10.1016/j.micres.2020.126655] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/15/2020] [Accepted: 11/18/2020] [Indexed: 11/29/2022]
Abstract
How cell morphology is maintained in thermophilic bacteria is unknown. In this study, the functions and mechanisms of the potential cell shape determinants (e.g. MreB, MreC, MreD and RodA homologues) of the model extremely thermophilic bacterium Thermus thermophilus were initially analyzed. Deletion of mreC, mreD or rodA only resulted in heterozygous mutants indicating that these genes are all essential. In the MreB-inhibited (by A22) strain and the heterozygous mreC, mreD or rodA mutant, cell morphologies were drastically changed, and enlarged spherical cells were eventually dead indicating that they are vital for cell shape maintenance. When fused to sGFP, MreB, MreC, MreD, RodA, and the enzymes involved in peptidoglycan synthesis (e.g. PBP2 and MurG) exhibited similar subcellular localization pattern, appearing as patches, or bands slightly angled to the cell length. The localizations and functions of all the 6 proteins required a natural peptidoglycan synthesis pattern, additionally those of MreD, RodA and MurG were dependent on MreB polymerization. Consistently, through comprehensive bacterial two-hybrid analyses, it was revealed that MreB could interact with itself, MreC, MreD, RodA and MurG, and MreC could associate with PBP2. In conclusion, in T. thermophilus, MreB, MreC, MreD, RodA and the peptidoglycan synthesis enzymes probably form a network of interactions centered with MreB and bridged with MreC, thereby maintaining cell morphology.
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Affiliation(s)
- Haijuan Li
- College of Biological and Environmental Engineering, Xi'an University, No. 168 South Taibai Road, Xi'an, 710065, China.
| | - Tianpeng Gao
- College of Biological and Environmental Engineering, Xi'an University, No. 168 South Taibai Road, Xi'an, 710065, China
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Jolly SM, Gainetdinov I, Jouravleva K, Zhang H, Strittmatter L, Bailey SM, Hendricks GM, Dhabaria A, Ueberheide B, Zamore PD. Thermus thermophilus Argonaute Functions in the Completion of DNA Replication. Cell 2020; 182:1545-1559.e18. [PMID: 32846159 PMCID: PMC7502556 DOI: 10.1016/j.cell.2020.07.036] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 06/25/2020] [Accepted: 07/24/2020] [Indexed: 01/06/2023]
Abstract
In many eukaryotes, Argonaute proteins, guided by short RNA sequences, defend cells against transposons and viruses. In the eubacterium Thermus thermophilus, the DNA-guided Argonaute TtAgo defends against transformation by DNA plasmids. Here, we report that TtAgo also participates in DNA replication. In vivo, TtAgo binds 15- to 18-nt DNA guides derived from the chromosomal region where replication terminates and associates with proteins known to act in DNA replication. When gyrase, the sole T. thermophilus type II topoisomerase, is inhibited, TtAgo allows the bacterium to finish replicating its circular genome. In contrast, loss of gyrase and TtAgo activity slows growth and produces long sausage-like filaments in which the individual bacteria are linked by DNA. Finally, wild-type T. thermophilus outcompetes an otherwise isogenic strain lacking TtAgo. We propose that the primary role of TtAgo is to help T. thermophilus disentangle the catenated circular chromosomes generated by DNA replication.
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Affiliation(s)
- Samson M Jolly
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Howard Hughes Medical Institute and RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Ildar Gainetdinov
- Howard Hughes Medical Institute and RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Karina Jouravleva
- Howard Hughes Medical Institute and RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Han Zhang
- Howard Hughes Medical Institute and RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Lara Strittmatter
- Department of Radiology, Division of Cell Biology and Imaging, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Shannon M Bailey
- Howard Hughes Medical Institute and RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Gregory M Hendricks
- Department of Radiology, Division of Cell Biology and Imaging, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Avantika Dhabaria
- Proteomics Laboratory, Division of Advanced Research Technologies, New York University School of Medicine, New York, NY 10016, USA
| | - Beatrix Ueberheide
- Proteomics Laboratory, Division of Advanced Research Technologies, New York University School of Medicine, New York, NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA; Center for Cognitive Neurology, Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
| | - Phillip D Zamore
- Howard Hughes Medical Institute and RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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Abstract
Proper chromosome segregation during cell division is essential in all domains of life. In the majority of bacterial species, faithful chromosome segregation is mediated by the tripartite ParABS system, consisting of an ATPase protein ParA, a CTPase and DNA-binding protein ParB, and a centromere-like parS site. The parS site is most often located near the origin of replication and is segregated first after chromosome replication. ParB nucleates on parS before binding to adjacent non-specific DNA to form a multimeric nucleoprotein complex. ParA interacts with ParB to drive the higher-order ParB–DNA complex, and hence the replicating chromosomes, to each daughter cell. Here, we review the various models for the formation of the ParABS complex and describe its role in segregating the origin-proximal region of the chromosome. Additionally, we discuss outstanding questions and challenges in understanding bacterial chromosome segregation.
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Affiliation(s)
- Adam S B Jalal
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Tung B K Le
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom
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Kawalek A, Wawrzyniak P, Bartosik AA, Jagura-Burdzy G. Rules and Exceptions: The Role of Chromosomal ParB in DNA Segregation and Other Cellular Processes. Microorganisms 2020; 8:E105. [PMID: 31940850 PMCID: PMC7022226 DOI: 10.3390/microorganisms8010105] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/07/2020] [Accepted: 01/09/2020] [Indexed: 12/11/2022] Open
Abstract
The segregation of newly replicated chromosomes in bacterial cells is a highly coordinated spatiotemporal process. In the majority of bacterial species, a tripartite ParAB-parS system, composed of an ATPase (ParA), a DNA-binding protein (ParB), and its target(s) parS sequence(s), facilitates the initial steps of chromosome partitioning. ParB nucleates around parS(s) located in the vicinity of newly replicated oriCs to form large nucleoprotein complexes, which are subsequently relocated by ParA to distal cellular compartments. In this review, we describe the role of ParB in various processes within bacterial cells, pointing out interspecies differences. We outline recent progress in understanding the ParB nucleoprotein complex formation and its role in DNA segregation, including ori positioning and anchoring, DNA condensation, and loading of the structural maintenance of chromosome (SMC) proteins. The auxiliary roles of ParBs in the control of chromosome replication initiation and cell division, as well as the regulation of gene expression, are discussed. Moreover, we catalog ParB interacting proteins. Overall, this work highlights how different bacterial species adapt the DNA partitioning ParAB-parS system to meet their specific requirements.
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Affiliation(s)
| | | | | | - Grazyna Jagura-Burdzy
- Department of Microbial Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; (A.K.); (P.W.); (A.A.B.)
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