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Contente D, Díaz-Formoso L, Feito J, Hernández PE, Muñoz-Atienza E, Borrero J, Poeta P, Cintas LM. Genomic and Functional Evaluation of Two Lacticaseibacillus paracasei and Two Lactiplantibacillus plantarum Strains, Isolated from a Rearing Tank of Rotifers ( Brachionus plicatilis), as Probiotics for Aquaculture. Genes (Basel) 2024; 15:64. [PMID: 38254954 PMCID: PMC10815930 DOI: 10.3390/genes15010064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/21/2023] [Accepted: 12/30/2023] [Indexed: 01/24/2024] Open
Abstract
Aquaculture plays a crucial role in meeting the increasing global demand for food and protein sources. However, its expansion is followed by increasing challenges, such as infectious disease outbreaks and antibiotic misuse. The present study focuses on the genetic and functional analyses of two Lacticaseibacillus paracasei (BF3 and RT4) and two Lactiplantibacillus plantarum (BF12 and WT12) strains isolated from a rotifer cultivation tank used for turbot larviculture. Whole-genome sequencing (WGS) and bioinformatics analyses confirmed their probiotic potential, the absence of transferable antibiotic resistance genes, and the absence of virulence and pathogenicity factors. Bacteriocin mining identified a gene cluster encoding six plantaricins, suggesting their role in the antimicrobial activity exerted by these strains. In vitro cell-free protein synthesis (IV-CFPS) analyses was used to evaluate the expression of the plantaricin genes. The in vitro-synthesized class IIb (two-peptide bacteriocins) plantaricin E/F (PlnE/F) exerted antimicrobial activity against three indicator microorganisms, including the well-known ichthyopathogen Lactococcus garvieae. Furthermore, MALDI-TOF MS on colonies detected the presence of a major peptide that matches the dimeric form of plantaricins E (PlnE) and F (PlnF). This study emphasizes the importance of genome sequencing and bioinformatic analysis for evaluating aquaculture probiotic candidates. Moreover, it provides valuable insights into their genetic features and antimicrobial mechanisms, paving the way for their application as probiotics in larviculture, which is a major bottleneck in aquaculture.
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Affiliation(s)
- Diogo Contente
- Grupo de Seguridad y Calidad de los Alimentos por Bacterias Lácticas, Bacteriocinas y Probióticos (SEGABALBP), Sección Departamental de Nutrición y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain; (D.C.); (L.D.-F.); (P.E.H.); (E.M.-A.); (J.B.); (L.M.C.)
| | - Lara Díaz-Formoso
- Grupo de Seguridad y Calidad de los Alimentos por Bacterias Lácticas, Bacteriocinas y Probióticos (SEGABALBP), Sección Departamental de Nutrición y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain; (D.C.); (L.D.-F.); (P.E.H.); (E.M.-A.); (J.B.); (L.M.C.)
| | - Javier Feito
- Grupo de Seguridad y Calidad de los Alimentos por Bacterias Lácticas, Bacteriocinas y Probióticos (SEGABALBP), Sección Departamental de Nutrición y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain; (D.C.); (L.D.-F.); (P.E.H.); (E.M.-A.); (J.B.); (L.M.C.)
| | - Pablo E. Hernández
- Grupo de Seguridad y Calidad de los Alimentos por Bacterias Lácticas, Bacteriocinas y Probióticos (SEGABALBP), Sección Departamental de Nutrición y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain; (D.C.); (L.D.-F.); (P.E.H.); (E.M.-A.); (J.B.); (L.M.C.)
| | - Estefanía Muñoz-Atienza
- Grupo de Seguridad y Calidad de los Alimentos por Bacterias Lácticas, Bacteriocinas y Probióticos (SEGABALBP), Sección Departamental de Nutrición y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain; (D.C.); (L.D.-F.); (P.E.H.); (E.M.-A.); (J.B.); (L.M.C.)
| | - Juan Borrero
- Grupo de Seguridad y Calidad de los Alimentos por Bacterias Lácticas, Bacteriocinas y Probióticos (SEGABALBP), Sección Departamental de Nutrición y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain; (D.C.); (L.D.-F.); (P.E.H.); (E.M.-A.); (J.B.); (L.M.C.)
| | - Patrícia Poeta
- Microbiology and Antibiotic Resistance Team (MicroART), Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal;
- Associate Laboratory for Animal and Veterinary Science (AL4AnimalS), University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal
| | - Luis M. Cintas
- Grupo de Seguridad y Calidad de los Alimentos por Bacterias Lácticas, Bacteriocinas y Probióticos (SEGABALBP), Sección Departamental de Nutrición y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain; (D.C.); (L.D.-F.); (P.E.H.); (E.M.-A.); (J.B.); (L.M.C.)
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Haudiquet M, de Sousa JM, Touchon M, Rocha EPC. Selfish, promiscuous and sometimes useful: how mobile genetic elements drive horizontal gene transfer in microbial populations. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210234. [PMID: 35989606 PMCID: PMC9393566 DOI: 10.1098/rstb.2021.0234] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Horizontal gene transfer (HGT) drives microbial adaptation but is often under the control of mobile genetic elements (MGEs) whose interests are not necessarily aligned with those of their hosts. In general, transfer is costly to the donor cell while potentially beneficial to the recipients. The diversity and plasticity of cell–MGEs interactions, and those among MGEs, result in complex evolutionary processes where the source, or even the existence of selection for maintaining a function in the genome, is often unclear. For example, MGE-driven HGT depends on cell envelope structures and defense systems, but many of these are transferred by MGEs themselves. MGEs can spur periods of intense gene transfer by increasing their own rates of horizontal transmission upon communicating, eavesdropping, or sensing the environment and the host physiology. This may result in high-frequency transfer of host genes unrelated to the MGE. Here, we review how MGEs drive HGT and how their transfer mechanisms, selective pressures and genomic traits affect gene flow, and therefore adaptation, in microbial populations. The encoding of many adaptive niche-defining microbial traits in MGEs means that intragenomic conflicts and alliances between cells and their MGEs are key to microbial functional diversification. This article is part of a discussion meeting issue ‘Genomic population structures of microbial pathogens’.
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Affiliation(s)
- Matthieu Haudiquet
- Institut Pasteur, Université de Paris Cité, CNRS UMR3525, Microbial Evolutionary Genomics, Paris 75015, France
| | - Jorge Moura de Sousa
- Institut Pasteur, Université de Paris Cité, CNRS UMR3525, Microbial Evolutionary Genomics, Paris 75015, France
| | - Marie Touchon
- Institut Pasteur, Université de Paris Cité, CNRS UMR3525, Microbial Evolutionary Genomics, Paris 75015, France
| | - Eduardo P C Rocha
- Institut Pasteur, Université de Paris Cité, CNRS UMR3525, Microbial Evolutionary Genomics, Paris 75015, France
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Mosley OE, Gios E, Close M, Weaver L, Daughney C, Handley KM. Nitrogen cycling and microbial cooperation in the terrestrial subsurface. THE ISME JOURNAL 2022; 16:2561-2573. [PMID: 35941171 PMCID: PMC9562985 DOI: 10.1038/s41396-022-01300-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 07/19/2022] [Accepted: 07/22/2022] [Indexed: 11/25/2022]
Abstract
The nitrogen cycle plays a major role in aquatic nitrogen transformations, including in the terrestrial subsurface. However, the variety of transformations remains understudied. To determine how nitrogen cycling microorganisms respond to different aquifer chemistries, we sampled groundwater with varying nutrient and oxygen contents. Genes and transcripts involved in major nitrogen-cycling pathways were quantified from 55 and 26 sites, respectively, and metagenomes and metatranscriptomes were analyzed from a subset of oxic and dysoxic sites (0.3-1.1 mg/L bulk dissolved oxygen). Nitrogen-cycling mechanisms (e.g. ammonia oxidation, denitrification, dissimilatory nitrate reduction to ammonium) were prevalent and highly redundant, regardless of site-specific physicochemistry or nitrate availability, and present in 40% of reconstructed genomes, suggesting that nitrogen cycling is a core function of aquifer communities. Transcriptional activity for nitrification, denitrification, nitrite-dependent anaerobic methane oxidation and anaerobic ammonia oxidation (anammox) occurred simultaneously in oxic and dysoxic groundwater, indicating the availability of oxic-anoxic interfaces. Concurrent activity by these microorganisms indicates potential synergisms through metabolite exchange across these interfaces (e.g. nitrite and oxygen). Fragmented denitrification pathway encoding and transcription was widespread among groundwater bacteria, although a considerable proportion of associated transcriptional activity was driven by complete denitrifiers, especially under dysoxic conditions. Despite large differences in transcription, the capacity for the final steps of denitrification was largely invariant to aquifer conditions, and most genes and transcripts encoding N2O reductases were the atypical Sec-dependant type, suggesting energy-efficiency prioritization. Results provide insights into the capacity for cooperative relationships in groundwater communities, and the richness and complexity of metabolic mechanisms leading to the loss of fixed nitrogen.
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de Korne-Elenbaas J, Bruisten SM, van Dam AP, Maiden MCJ, Harrison OB. The Neisseria gonorrhoeae Accessory Genome and Its Association with the Core Genome and Antimicrobial Resistance. Microbiol Spectr 2022; 10:e0265421. [PMID: 35604129 PMCID: PMC9241924 DOI: 10.1128/spectrum.02654-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 04/14/2022] [Indexed: 01/22/2023] Open
Abstract
The bacterial accessory genome provides the genetic flexibility needed to facilitate environment and host adaptation. In Neisseria gonorrhoeae, known accessory elements include plasmids which can transfer and mediate antimicrobial resistance (AMR); however, chromosomal accessory genes could also play a role in AMR. Here, the gonococcal accessory genome was characterized using gene-by-gene approaches and its association with the core genome and AMR were assessed. The gonococcal accessory gene pool consisted of 247 genes, which were mainly genes located on large mobile genetic elements, phage associated genes, or genes encoding putative secretion systems. Accessory elements showed similar synteny across genomes, indicating either a predisposition for particular genomic locations or ancestral inheritance that are conserved during strain expansion. Significant associations were found between the prevalence of accessory elements and core genome multi-locus sequence types (cgMLST), consistent with a structured gonococcal population despite frequent horizontal gene transfer (HGT). Increased prevalence of putative DNA exchange regulators was significantly associated with AMR, which included a putative secretion system, methyltransferases and a toxin-antitoxin system. Although frequent HGT results in high genetic diversity in the gonococcus, we found that this is mediated by a small gene pool. In fact, a highly organized genome composition was identified with a strong association between the accessory and core genome. Increased prevalence of DNA exchange regulators in antimicrobial resistant isolates suggests that genetic material exchange plays a role in the development or maintenance of AMR. These findings enhance our understanding of gonococcal genome architecture and have important implications for gonococcal population biology. IMPORTANCE The emergence of antimicrobial resistance (AMR) against third generation cephalosporins in Neisseria gonorrhoeae is a major public health concern, as these are antibiotics of last resort for the effective treatment of gonorrhea. Although the resistance mechanisms against this class of antibiotics have not been entirely resolved, resistance against other classes of antibiotics, such as tetracyclines, is known to be mediated through plasmids, which are known gonococcal extra-chromosomal accessory elements. A complete assessment of the chromosomal accessory genome content and its role in AMR has not yet been undertaken. Here, we comprehensively characterize the gonococcal accessory genome to better understand genome architecture as well as the evolution and mechanisms of AMR in this species.
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Affiliation(s)
- Jolinda de Korne-Elenbaas
- Public Health Laboratory, Department of Infectious Diseases, Public Health Service of Amsterdam, Amsterdam, the Netherlands
- Amsterdam UMC, University of Amsterdam, Department of Medical Microbiology, Amsterdam Institute for Infection and Immunity (AI&II), Academic Medical Center, Amsterdam, the Netherlands
| | - Sylvia M. Bruisten
- Public Health Laboratory, Department of Infectious Diseases, Public Health Service of Amsterdam, Amsterdam, the Netherlands
- Amsterdam UMC, University of Amsterdam, Amsterdam Institute for Infection and Immunity (AI&II), Amsterdam, the Netherlands
| | - Alje P. van Dam
- Public Health Laboratory, Department of Infectious Diseases, Public Health Service of Amsterdam, Amsterdam, the Netherlands
- Amsterdam UMC, University of Amsterdam, Department of Medical Microbiology, Amsterdam Institute for Infection and Immunity (AI&II), Academic Medical Center, Amsterdam, the Netherlands
| | - Martin C. J. Maiden
- Department of Zoology, Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Odile B. Harrison
- Department of Zoology, Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
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Richard D, Roumagnac P, Pruvost O, Lefeuvre P. A network approach to decipher the dynamics of Lysobacteraceae plasmid gene sharing. Mol Ecol 2022; 32:2660-2673. [PMID: 35593155 DOI: 10.1111/mec.16536] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 04/21/2022] [Accepted: 05/05/2022] [Indexed: 11/27/2022]
Abstract
Plasmids provide an efficient vehicle for gene sharing among bacterial populations, playing a key role in bacterial evolution. Network approaches are particularly suitable to represent multipartite relationships and are useful tools to characterize plasmid-mediated gene sharing events. The Lysobacteraceae bacterial family gathers plant commensal, plant pathogenic and opportunistic human pathogens for which plasmid mediated adaptation was reported. We searched for homologues of plasmid gene sequences from this family in all the diversity of available bacterial genome sequences and built a network of plasmid gene sharing from the results. While plasmid genes are openly shared between the bacteria of the Lysobacteraceae family, taxonomy strongly defined the boundaries of these exchanges, that only barely reached other families. Most inferred plasmid gene sharing events involved a few genes only, and evidence of full plasmid transfers were restricted to taxonomically close taxon. We detected multiple plasmid-chromosome gene transfers, among which the otherwise known sharing of a heavy metal resistance transposon. In the network, bacterial lifestyles shaped sub-structures of isolates colonizing specific ecological niches and harboring specific types of resistance genes. Genes associated to pathogenicity or antibiotic and metal resistance were among those that most importantly structured the network, highlighting the imprints of human-mediated selective pressure on pathogenic populations. A massive sequencing effort on environmental Lysobacteraceae is therefore required to refine our understanding on how this reservoir fuels the emergence and the spread of genes amongst this family and its potential impact on plant, animal and human health.
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Affiliation(s)
- D Richard
- Cirad, UMR PVBMT, F-97410 St Pierre, Réunion, France.,ANSES, Plant Health Laboratory, F-97410 St Pierre, Réunion, France.,Université de La Réunion, La Réunion, France
| | - P Roumagnac
- Montpellier, France.,PHIM Plant Health Institute, Univ Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France
| | - O Pruvost
- Cirad, UMR PVBMT, F-97410 St Pierre, Réunion, France
| | - P Lefeuvre
- Cirad, UMR PVBMT, F-97410 St Pierre, Réunion, France
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Bacterial Composition and Interactions in Raw Milk and Teat Skin of Dairy Cows. FERMENTATION 2022. [DOI: 10.3390/fermentation8050235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The microbiota in raw milk plays an important role in the health of dairy cows and the safety of dairy products, which might be influenced by that in teat skin. However, the microbiota composition in raw milk and teat skin, as well as the bacterial interaction between the two adjacent spatial locations, remains elusive. Here, we investigated the composition, diversity, and co-occurrence network of the bacterial communities in raw milk and on teat skin, as well as the shift of bacterial communities during the teat bath using 469 samples from 156 individual cows. We observed that raw milk and teat skin harbored significantly different bacterial communities according to an assessment of the genera numbers (p < 0.05) and PCoA analysis (ANOSIM p < 0.05). The microbiota in raw milk was dominated by Proteobacteria (58.5% in relative abundance) at the phylum level and by Pseudomonas (51.2%) at the genus level, while that in teat skin was dominated by Firmicutes (46.9%) at the phylum level and by Pseudomonas (11.0%) at the genus level. We observed a massive difference between the bacterial subnetworks in raw milk and teat, and the bacterial abundance in these two adjacent spatial locations was positively correlated (p < 0.05). Using Bayesian algorithms, we identified that 92.1% of bacteria in raw milk were transferred from teat skin, while 63.6% of bacteria on teat skin were transferred from raw milk. Moreover, microbiota composition in teat skin could be affected by the teat bath with iodine disinfectant, which tended to be more similar to that in raw milk after the teat bath (p < 0.05), while the abundance of the dominant genus Pseudomonas significantly increased (p < 0.05). These findings expand our knowledge on the microbiota composition in teat skin and raw milk, as well as the interaction between these two adjacent spatial locations.
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7
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Haraoui LP. Networked collective microbiomes and the rise of subcellular 'units of life'. Trends Microbiol 2021; 30:112-119. [PMID: 34696928 DOI: 10.1016/j.tim.2021.09.011] [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: 03/31/2021] [Revised: 09/21/2021] [Accepted: 09/27/2021] [Indexed: 10/20/2022]
Abstract
Microbiomes are generally conceived of as one element of a pair - their partner being the habitat they occupy. I call this common scientific practice 'pair-thinking'. Research into antimicrobial resistance and its underlying anthropogenic drivers highlights the growing footprint occupied by mobile genetic elements (MGEs). Furthermore, these MGEs are known to circulate widely between microbiomes. Using a pluralistic framework anchored within a processual microbial ontology, these observations point to a reframing of microbiomes as networked and collective, thus challenging pair-thinking. Such a shift has implications for the future of microbiome research, from conceptual and methodological perspectives, and exposes the impacts of anthropogenic forces on the evolution of microbiomes and the functions they carry out.
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Affiliation(s)
- Louis-Patrick Haraoui
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.
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Pilar AVC, Petronella N, Dussault FM, Verster AJ, Bekal S, Levesque RC, Goodridge L, Tamber S. Similar yet different: phylogenomic analysis to delineate Salmonella and Citrobacter species boundaries. BMC Genomics 2020; 21:377. [PMID: 32471418 PMCID: PMC7257147 DOI: 10.1186/s12864-020-06780-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 05/13/2020] [Indexed: 12/14/2022] Open
Abstract
Background Salmonella enterica is a leading cause of foodborne illness worldwide resulting in considerable public health and economic costs. Testing for the presence of this pathogen in food is often hampered by the presence of background microflora that may present as Salmonella (false positives). False positive isolates belonging to the genus Citrobacter can be difficult to distinguish from Salmonella due to similarities in their genetics, cell surface antigens, and other phenotypes. In order to understand the genetic basis of these similarities, a comparative genomic approach was used to define the pan-, core, accessory, and unique coding sequences of a representative population of Salmonella and Citrobacter strains. Results Analysis of the genomic content of 58 S. enterica strains and 37 Citrobacter strains revealed the presence of 31,130 and 1540 coding sequences within the pan- and core genome of this population. Amino acid sequences unique to either Salmonella (n = 1112) or Citrobacter (n = 195) were identified and revealed potential niche-specific adaptations. Phylogenetic network analysis of the protein families encoded by the pan-genome indicated that genetic exchange between Salmonella and Citrobacter may have led to the acquisition of similar traits and also diversification within the genera. Conclusions Core genome analysis suggests that the Salmonella enterica and Citrobacter populations investigated here share a common evolutionary history. Comparative analysis of the core and pan-genomes was able to define the genetic features that distinguish Salmonella from Citrobacter and highlight niche specific adaptations.
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Affiliation(s)
| | - Nicholas Petronella
- Bureau of Food Surveillance and Science Integration, Health Canada, Ottawa, Ontario, Canada
| | - Forest M Dussault
- Bureau of Food Surveillance and Science Integration, Health Canada, Ottawa, Ontario, Canada
| | - Adrian J Verster
- Bureau of Food Surveillance and Science Integration, Health Canada, Ottawa, Ontario, Canada
| | - Sadjia Bekal
- Laboratoire de santé publique du Québec, Ste-Anne-de-Bellevue, Quebec, Canada
| | - Roger C Levesque
- Institute for Integrative and Systems Biology (IBIS), Université Laval, Quebec, Quebec, Canada
| | - Lawrence Goodridge
- Department of Food Science and Agricultural Chemistry, Faculty of Agricultural and Environmental Sciences, McGill University, Ste-Anne-de-Bellevue, Quebec, Canada.,Food Science Department, University of Guelph, Guelph, Ontario, Canada
| | - Sandeep Tamber
- Bureau of Microbial Hazards, Health Canada, Ottawa, Ontario, Canada.
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Gysi DM, Nowick K. Construction, comparison and evolution of networks in life sciences and other disciplines. J R Soc Interface 2020; 17:20190610. [PMID: 32370689 PMCID: PMC7276545 DOI: 10.1098/rsif.2019.0610] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 04/09/2020] [Indexed: 12/12/2022] Open
Abstract
Network approaches have become pervasive in many research fields. They allow for a more comprehensive understanding of complex relationships between entities as well as their group-level properties and dynamics. Many networks change over time, be it within seconds or millions of years, depending on the nature of the network. Our focus will be on comparative network analyses in life sciences, where deciphering temporal network changes is a core interest of molecular, ecological, neuropsychological and evolutionary biologists. Further, we will take a journey through different disciplines, such as social sciences, finance and computational gastronomy, to present commonalities and differences in how networks change and can be analysed. Finally, we envision how borrowing ideas from these disciplines could enrich the future of life science research.
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Affiliation(s)
- Deisy Morselli Gysi
- Department of Computer Science, Interdisciplinary Center of Bioinformatics, University of Leipzig, 04109 Leipzig, Germany
- Swarm Intelligence and Complex Systems Group, Faculty of Mathematics and Computer Science, University of Leipzig, 04109 Leipzig, Germany
- Center for Complex Networks Research, Northeastern University, 177 Huntington Avenue, Boston, MA 02115, USA
| | - Katja Nowick
- Human Biology Group, Institute for Biology, Faculty of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Königin-Luise-Straβe 1-3, 14195 Berlin, Germany
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Antibiotic resistance in Pseudomonas aeruginosa - Mechanisms, epidemiology and evolution. Drug Resist Updat 2019; 44:100640. [PMID: 31492517 DOI: 10.1016/j.drup.2019.07.002] [Citation(s) in RCA: 233] [Impact Index Per Article: 46.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/11/2019] [Accepted: 07/12/2019] [Indexed: 12/13/2022]
Abstract
Antibiotics are powerful drugs used in the treatment of bacterial infections. The inappropriate use of these medicines has driven the dissemination of antibiotic resistance (AR) in most bacteria. Pseudomonas aeruginosa is an opportunistic pathogen commonly involved in environmental- and difficult-to-treat hospital-acquired infections. This species is frequently resistant to several antibiotics, being in the "critical" category of the WHO's priority pathogens list for research and development of new antibiotics. In addition to a remarkable intrinsic resistance to several antibiotics, P. aeruginosa can acquire resistance through chromosomal mutations and acquisition of AR genes. P. aeruginosa has one of the largest bacterial genomes and possesses a significant assortment of genes acquired by horizontal gene transfer (HGT), which are frequently localized within integrons and mobile genetic elements (MGEs), such as transposons, insertion sequences, genomic islands, phages, plasmids and integrative and conjugative elements (ICEs). This genomic diversity results in a non-clonal population structure, punctuated by specific clones that are associated with significant morbidity and mortality worldwide, the so-called high-risk clones. Acquisition of MGEs produces a fitness cost in the host, that can be eased over time by compensatory mutations during MGE-host coevolution. Even though plasmids and ICEs are important drivers of AR, the underlying evolutionary traits that promote this dissemination are poorly understood. In this review, we provide a comprehensive description of the main strategies involved in AR in P. aeruginosa and the leading drivers of HGT in this species. The most recently developed genomic tools that allowed a better understanding of the features contributing for the success of P. aeruginosa are discussed.
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Botelho J, Grosso F, Peixe L. WITHDRAWN: Antibiotic resistance in Pseudomonas aeruginosa – mechanisms, epidemiology and evolution. Drug Resist Updat 2019. [DOI: 10.1016/j.drup.2019.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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13
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Pillonel T, Bertelli C, Aeby S, de Barsy M, Jacquier N, Kebbi-Beghdadi C, Mueller L, Vouga M, Greub G. Sequencing the Obligate Intracellular Rhabdochlamydia helvetica within Its Tick Host Ixodes ricinus to Investigate Their Symbiotic Relationship. Genome Biol Evol 2019; 11:1334-1344. [PMID: 30949677 PMCID: PMC6490308 DOI: 10.1093/gbe/evz072] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2019] [Indexed: 12/15/2022] Open
Abstract
The Rhabdochlamydiaceae family is one of the most widely distributed within the phylum Chlamydiae, but most of its members remain uncultivable. Rhabdochlamydia 16S rRNA was recently reported in more than 2% of 8,534 pools of ticks from Switzerland. Shotgun metagenomics was performed on a pool of five female Ixodes ricinus ticks presenting a high concentration of chlamydial DNA, allowing the assembly of a high-quality draft genome. About 60% of sequence reads originated from a single bacterial population that was named "Candidatus Rhabdochlamydia helvetica" whereas only few thousand reads mapped to the genome of "Candidatus Midichloria mitochondrii," a symbiont normally observed in all I. ricinus females. The 1.8 Mbp genome of R. helvetica is smaller than other Chlamydia-related bacteria. Comparative analyses with other chlamydial genomes identified transposases of the PD-(D/E)XK nuclease family that are unique to this new genome. These transposases show evidence of interphylum horizontal gene transfers between multiple arthropod endosymbionts, including Cardinium spp. (Bacteroidetes) and diverse proteobacteria such as Wolbachia, Rickettsia spp. (Rickettsiales), and Caedimonas varicaedens (Holosporales). Bacterial symbionts were previously suggested to provide B-vitamins to hematophagous hosts. However, incomplete metabolic capacities including for B-vitamin biosynthesis, high bacterial density and limited prevalence suggest that R. helvetica is parasitic rather than symbiotic to its host. The identification of novel Rhabdochlamydia strains in different hosts and their sequencing will help understanding if members of this genus have become highly specialized parasites with reduced genomes, like the Chlamydiaceae, or if they could be pathogenic to humans using ticks as a transmission vector.
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Affiliation(s)
- Trestan Pillonel
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Claire Bertelli
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Sébastien Aeby
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Marie de Barsy
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Nicolas Jacquier
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Carole Kebbi-Beghdadi
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Linda Mueller
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Manon Vouga
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Gilbert Greub
- Center for Research on Intracellular Bacteria, Institute of Microbiology, Lausanne University Hospital, University of Lausanne, Switzerland
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14
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Corel E, Méheust R, Watson AK, McInerney JO, Lopez P, Bapteste E. Bipartite Network Analysis of Gene Sharings in the Microbial World. Mol Biol Evol 2019; 35:899-913. [PMID: 29346651 PMCID: PMC5888944 DOI: 10.1093/molbev/msy001] [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] [Indexed: 12/19/2022] Open
Abstract
Extensive microbial gene flows affect how we understand virology, microbiology, medical sciences, genetic modification, and evolutionary biology. Phylogenies only provide a narrow view of these gene flows: plasmids and viruses, lacking core genes, cannot be attached to cellular life on phylogenetic trees. Yet viruses and plasmids have a major impact on cellular evolution, affecting both the gene content and the dynamics of microbial communities. Using bipartite graphs that connect up to 149,000 clusters of homologous genes with 8,217 related and unrelated genomes, we can in particular show patterns of gene sharing that do not map neatly with the organismal phylogeny. Homologous genes are recycled by lateral gene transfer, and multiple copies of homologous genes are carried by otherwise completely unrelated (and possibly nested) genomes, that is, viruses, plasmids and prokaryotes. When a homologous gene is present on at least one plasmid or virus and at least one chromosome, a process of "gene externalization," affected by a postprocessed selected functional bias, takes place, especially in Bacteria. Bipartite graphs give us a view of vertical and horizontal gene flow beyond classic taxonomy on a single very large, analytically tractable, graph that goes beyond the cellular Web of Life.
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Affiliation(s)
- Eduardo Corel
- Unité Mixte de Recherche 7138 Evolution Paris-Seine, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Sorbonne Université, Université Pierre et Marie Curie, Paris, France
| | - Raphaël Méheust
- Unité Mixte de Recherche 7138 Evolution Paris-Seine, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Sorbonne Université, Université Pierre et Marie Curie, Paris, France
| | - Andrew K Watson
- Unité Mixte de Recherche 7138 Evolution Paris-Seine, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Sorbonne Université, Université Pierre et Marie Curie, Paris, France
| | - James O McInerney
- Chair in Evolutionary Biology, The University of Manchester, United Kingdom
| | - Philippe Lopez
- Unité Mixte de Recherche 7138 Evolution Paris-Seine, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Sorbonne Université, Université Pierre et Marie Curie, Paris, France
| | - Eric Bapteste
- Unité Mixte de Recherche 7138 Evolution Paris-Seine, Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Sorbonne Université, Université Pierre et Marie Curie, Paris, France
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15
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Watson AK, Lannes R, Pathmanathan JS, Méheust R, Karkar S, Colson P, Corel E, Lopez P, Bapteste E. The Methodology Behind Network Thinking: Graphs to Analyze Microbial Complexity and Evolution. Methods Mol Biol 2019; 1910:271-308. [PMID: 31278668 DOI: 10.1007/978-1-4939-9074-0_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In the post genomic era, large and complex molecular datasets from genome and metagenome sequencing projects expand the limits of what is possible for bioinformatic analyses. Network-based methods are increasingly used to complement phylogenetic analysis in studies in molecular evolution, including comparative genomics, classification, and ecological studies. Using network methods, the vertical and horizontal relationships between all genes or genomes, whether they are from cellular chromosomes or mobile genetic elements, can be explored in a single expandable graph. In recent years, development of new methods for the construction and analysis of networks has helped to broaden the availability of these approaches from programmers to a diversity of users. This chapter introduces the different kinds of networks based on sequence similarity that are already available to tackle a wide range of biological questions, including sequence similarity networks, gene-sharing networks and bipartite graphs, and a guide for their construction and analyses.
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Affiliation(s)
- Andrew K Watson
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France
| | - Romain Lannes
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France
| | - Jananan S Pathmanathan
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France
| | - Raphaël Méheust
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France
| | - Slim Karkar
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France
- Department of Ecology, Evolution, and Natural Resources, School of Environmental and Biological Sciences, Rutgers, The State University of NJ, New Brunswick, NJ, USA
| | - Philippe Colson
- Fondation Institut Hospitalo-Universitaire Méditerranée Infection, Pôle des Maladies Infectieuses et Tropicales Clinique et Biologique, Fédération de Bactériologie-Hygiène-Virologie, Centre Hospitalo-Universitaire Tione, Assistance Publique-Hôpitaux de Marseille, Marseille, France
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE) UM63, CNRS 7278, IRD 198, INSERM U1095, Aix-Marseille University, Marseille, France
| | - Eduardo Corel
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France
| | - Philippe Lopez
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France
| | - Eric Bapteste
- Sorbonne Universités, Institut de Biologie Paris-Seine, UPMC Université Paris 6, Paris, France.
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16
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Chen W, Mandali S, Hancock SP, Kumar P, Collazo M, Cascio D, Johnson RC. Multiple serine transposase dimers assemble the transposon-end synaptic complex during IS 607-family transposition. eLife 2018; 7:e39611. [PMID: 30289389 PMCID: PMC6188088 DOI: 10.7554/elife.39611] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 09/18/2018] [Indexed: 11/13/2022] Open
Abstract
IS607-family transposons are unusual because they do not have terminal inverted repeats or generate target site duplications. They encode two protein-coding genes, but only tnpA is required for transposition. Our X-ray structures confirm that TnpA is a member of the serine recombinase (SR) family, but the chemically-inactive quaternary structure of the dimer, along with the N-terminal location of the DNA binding domain, are different from other SRs. TnpA dimers from IS1535 cooperatively associate with multiple subterminal repeats, which together with additional nonspecific binding, form a nucleoprotein filament on one transposon end that efficiently captures a second unbound end to generate the paired-end complex (PEC). Formation of the PEC does not require a change in the dimeric structure of the catalytic domain, but remodeling of the C-terminal α-helical region is involved. We posit that the PEC recruits a chemically-active conformer of TnpA to the transposon end to initiate DNA chemistry.
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Affiliation(s)
- Wenyang Chen
- Department of Biological ChemistryDavid Geffen School of Medicine, University of California at Los AngelesLos AngelesUnited States
| | - Sridhar Mandali
- Department of Biological ChemistryDavid Geffen School of Medicine, University of California at Los AngelesLos AngelesUnited States
| | - Stephen P Hancock
- Department of Biological ChemistryDavid Geffen School of Medicine, University of California at Los AngelesLos AngelesUnited States
| | - Pramod Kumar
- Department of Biological ChemistryDavid Geffen School of Medicine, University of California at Los AngelesLos AngelesUnited States
| | - Michael Collazo
- Department of Energy Institute of Genomics and ProteomicsUniversity of California at Los AngelesLos AngelesUnited States
| | - Duilio Cascio
- Department of Energy Institute of Genomics and ProteomicsUniversity of California at Los AngelesLos AngelesUnited States
| | - Reid C Johnson
- Department of Biological ChemistryDavid Geffen School of Medicine, University of California at Los AngelesLos AngelesUnited States
- Molecular Biology InstituteUniversity of California at Los AngelesLos AngelesUnited States
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17
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Cheaib B, Le Boulch M, Mercier PL, Derome N. Taxon-Function Decoupling as an Adaptive Signature of Lake Microbial Metacommunities Under a Chronic Polymetallic Pollution Gradient. Front Microbiol 2018; 9:869. [PMID: 29774016 PMCID: PMC5943556 DOI: 10.3389/fmicb.2018.00869] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Accepted: 04/16/2018] [Indexed: 11/29/2022] Open
Abstract
Adaptation of microbial communities to anthropogenic stressors can lead to reductions in microbial diversity and disequilibrium of ecosystem services. Such adaptation can change the molecular signatures of communities with differences in taxonomic and functional composition. Understanding the relationship between taxonomic and functional variation remains a critical issue in microbial ecology. Here, we assessed the taxonomic and functional diversity of a lake metacommunity system along a polymetallic pollution gradient caused by 60 years of chronic exposure to acid mine drainage (AMD). Our results highlight three adaptive signatures. First, a signature of taxon—function decoupling was detected in the microbial communities of moderately and highly polluted lakes. Second, parallel shifts in taxonomic composition occurred between polluted and unpolluted lakes. Third, variation in the abundance of functional modules suggested a gradual deterioration of ecosystem services (i.e., photosynthesis) and secondary metabolism in highly polluted lakes. Overall, changes in the abundance of taxa, function, and more importantly the polymetallic resistance genes such as copA, copB, czcA, cadR, cCusA, were correlated with trace metal content (mainly Cadmium) and acidity. Our findings highlight the impact of polymetallic pollution gradient at the lowest trophic levels.
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Affiliation(s)
- Bachar Cheaib
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Quebec, QC, Canada
| | - Malo Le Boulch
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Quebec, QC, Canada.,GenPhySE, Institut National de la Recherche Agronomique, Université de Toulouse, INPT, ENVT, Castanet-Tolosan, France
| | - Pierre-Luc Mercier
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Quebec, QC, Canada
| | - Nicolas Derome
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Quebec, QC, Canada
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18
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Peccoud J, Loiseau V, Cordaux R, Gilbert C. Massive horizontal transfer of transposable elements in insects. Proc Natl Acad Sci U S A 2017; 114:4721-4726. [PMID: 28416702 PMCID: PMC5422770 DOI: 10.1073/pnas.1621178114] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Horizontal transfer (HT) of genetic material is central to the architecture and evolution of prokaryote genomes. Within eukaryotes, the majority of HTs reported so far are transfers of transposable elements (TEs). These reports essentially come from studies focusing on specific lineages or types of TEs. Because of the lack of large-scale survey, the amount and impact of HT of TEs (HTT) in eukaryote evolution, as well as the trends and factors shaping these transfers, are poorly known. Here, we report a comprehensive analysis of HTT in 195 insect genomes, representing 123 genera and 13 of the 28 insect orders. We found that these insects were involved in at least 2,248 HTT events that essentially occurred during the last 10 My. We show that DNA transposons transfer horizontally more often than retrotransposons, and unveil phylogenetic relatedness and geographical proximity as major factors facilitating HTT in insects. Even though our study is restricted to a small fraction of insect biodiversity and to a recent evolutionary timeframe, the TEs we found to be horizontally transferred generated up to 24% (2.08% on average) of all nucleotides of insect genomes. Together, our results establish HTT as a major force shaping insect genome evolution.
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Affiliation(s)
- Jean Peccoud
- UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, Université de Poitiers, Poitiers F-86073, France
| | - Vincent Loiseau
- UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, Université de Poitiers, Poitiers F-86073, France
| | - Richard Cordaux
- UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, Université de Poitiers, Poitiers F-86073, France
| | - Clément Gilbert
- UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, Université de Poitiers, Poitiers F-86073, France
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19
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Cuecas A, Kanoksilapatham W, Gonzalez JM. Evidence of horizontal gene transfer by transposase gene analyses in Fervidobacterium species. PLoS One 2017; 12:e0173961. [PMID: 28426805 PMCID: PMC5398504 DOI: 10.1371/journal.pone.0173961] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 03/01/2017] [Indexed: 11/25/2022] Open
Abstract
Horizontal Gene Transfer (HGT) plays an important role in the physiology and evolution of microorganisms above all thermophilic prokaryotes. Some members of the Phylum Thermotogae (i.e., Thermotoga spp.) have been reported to present genomes constituted by a mosaic of genes from a variety of origins. This study presents a novel approach to search on the potential plasticity of Fervidobacterium genomes using putative transposase-encoding genes as the target of analysis. Transposases are key proteins involved in genomic DNA rearrangements. A comprehensive comparative analysis, including phylogeny, non-metric multidimensional scaling analysis of tetranucleotide frequencies, repetitive flanking sequences and divergence estimates, was performed on the transposase genes detected in four Fervidobacterium genomes: F. nodosum, F. pennivorans, F. islandicum and a new isolate (Fervidobacterium sp. FC2004). Transposase sequences were classified in different groups by their degree of similarity. The different methods used in this study pointed that over half of the transposase genes represented putative HGT events with closest relative sequences within the phylum Firmicutes, being Caldicellulosiruptor the genus showing highest gene sequence proximity. These results confirmed a direct evolutionary relationship through HGT between specific Fervidobacterium species and thermophilic Firmicutes leading to potential gene sequence and functionality sharing to thrive under similar environmental conditions. Transposase-encoding genes represent suitable targets to approach the plasticity and potential mosaicism of bacterial genomes.
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Affiliation(s)
- Alba Cuecas
- Institute of Natural Resources and Agrobiology, Spanish Council for Research, IRNAS-CSIC, Avda. Rena Mercedes 10, Sevilla, Spain
| | - Wirojne Kanoksilapatham
- Department of Microbiology, Faculty of Science, Silpakorn University, Nakhon Pathom, Thailand
| | - Juan M. Gonzalez
- Institute of Natural Resources and Agrobiology, Spanish Council for Research, IRNAS-CSIC, Avda. Rena Mercedes 10, Sevilla, Spain
- * E-mail:
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20
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Fondi M, Karkman A, Tamminen MV, Bosi E, Virta M, Fani R, Alm E, McInerney JO. "Every Gene Is Everywhere but the Environment Selects": Global Geolocalization of Gene Sharing in Environmental Samples through Network Analysis. Genome Biol Evol 2016; 8:1388-400. [PMID: 27190206 PMCID: PMC4898794 DOI: 10.1093/gbe/evw077] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The spatial distribution of microbes on our planet is famously formulated in the Baas Becking hypothesis as “everything is everywhere but the environment selects.” While this hypothesis does not strictly rule out patterns caused by geographical effects on ecology and historical founder effects, it does propose that the remarkable dispersal potential of microbes leads to distributions generally shaped by environmental factors rather than geographical distance. By constructing sequence similarity networks from uncultured environmental samples, we show that microbial gene pool distributions are not influenced nearly as much by geography as ecology, thus extending the Bass Becking hypothesis from whole organisms to microbial genes. We find that gene pools are shaped by their broad ecological niche (such as sea water, fresh water, host, and airborne). We find that freshwater habitats act as a gene exchange bridge between otherwise disconnected habitats. Finally, certain antibiotic resistance genes deviate from the general trend of habitat specificity by exhibiting a high degree of cross-habitat mobility. The strong cross-habitat mobility of antibiotic resistance genes is a cause for concern and provides a paradigmatic example of the rate by which genes colonize new habitats when new selective forces emerge.
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Affiliation(s)
- Marco Fondi
- Laboratory of Microbial and Molecular Evolution, Department of Biology, University of Florence, Italy Computational Biology Group, University of Florence, Italy
| | - Antti Karkman
- Department of Food and Environmental Sciences, University of Helsinki, Finland
| | - Manu V Tamminen
- Department of Environmental Systems Science, ETH Zürich, Switzerland Department of Aquatic Ecology, Eawag, Switzerland
| | - Emanuele Bosi
- Laboratory of Microbial and Molecular Evolution, Department of Biology, University of Florence, Italy Computational Biology Group, University of Florence, Italy
| | - Marko Virta
- Department of Food and Environmental Sciences, University of Helsinki, Finland
| | - Renato Fani
- Laboratory of Microbial and Molecular Evolution, Department of Biology, University of Florence, Italy Computational Biology Group, University of Florence, Italy
| | - Eric Alm
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology
| | - James O McInerney
- Department of Biology, National University of Ireland Maynooth, County Kildare, Ireland Computational Evolutionary Biology, Faculty of Life Sciences, The University of Manchester, United Kingdom
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21
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Metagenomic analysis of rapid gravity sand filter microbial communities suggests novel physiology of Nitrospira spp. ISME JOURNAL 2016; 10:2569-2581. [PMID: 27128989 DOI: 10.1038/ismej.2016.63] [Citation(s) in RCA: 131] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 02/29/2016] [Accepted: 03/19/2016] [Indexed: 01/30/2023]
Abstract
Rapid gravity sand filtration is a drinking water production technology widely used around the world. Microbially catalyzed processes dominate the oxidative transformation of ammonia, reduced manganese and iron, methane and hydrogen sulfide, which may all be present at millimolar concentrations when groundwater is the source water. In this study, six metagenomes from various locations within a groundwater-fed rapid sand filter (RSF) were analyzed. The community gene catalog contained most genes of the nitrogen cycle, with particular abundance in genes of the nitrification pathway. Genes involved in different carbon fixation pathways were also abundant, with the reverse tricarboxylic acid cycle pathway most abundant, consistent with an observed Nitrospira dominance. From the metagenomic data set, 14 near-complete genomes were reconstructed and functionally characterized. On the basis of their genetic content, a metabolic and geochemical model was proposed. The organisms represented by draft genomes had the capability to oxidize ammonium, nitrite, hydrogen sulfide, methane, potentially iron and manganese as well as to assimilate organic compounds. A composite Nitrospira genome was recovered, and amo-containing Nitrospira genome contigs were identified. This finding, together with the high Nitrospira abundance, and the abundance of atypical amo and hao genes, suggests the potential for complete ammonium oxidation by Nitrospira, and a major role of Nitrospira in the investigated RSFs and potentially other nitrifying environments.
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22
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Hologenome analysis of two marine sponges with different microbiomes. BMC Genomics 2016; 17:158. [PMID: 26926518 PMCID: PMC4772301 DOI: 10.1186/s12864-016-2501-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 02/18/2016] [Indexed: 01/09/2023] Open
Abstract
Background Sponges (Porifera) harbor distinct microbial consortia within their mesohyl interior. We herein analysed the hologenomes of Stylissa carteri and Xestospongia testudinaria, which notably differ in their microbiome content. Results Our analysis revealed that S. carteri has an expanded repertoire of immunological domains, specifically Scavenger Receptor Cysteine-Rich (SRCR)-like domains, compared to X. testudinaria. On the microbial side, metatranscriptome analyses revealed an overrepresentation of potential symbiosis-related domains in X. testudinaria. Conclusions Our findings provide genomic insights into the molecular mechanisms underlying host-symbiont coevolution and may serve as a roadmap for future hologenome analyses. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2501-0) contains supplementary material, which is available to authorized users.
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23
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Transposase interaction with the β sliding clamp: effects on insertion sequence proliferation and transposition rate. Sci Rep 2015; 5:13329. [PMID: 26306550 PMCID: PMC4549789 DOI: 10.1038/srep13329] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 07/23/2015] [Indexed: 01/05/2023] Open
Abstract
Insertion sequences (ISs) are ubiquitous and abundant mobile genetic elements in prokaryotic genomes. ISs often encode only one protein, the transposase, which catalyzes their transposition. Recent studies have shown that transposases of many different IS families interact with the β sliding clamp, a DNA replication factor of the host. However, it was unclear to what extent this interaction limits or favors the ability of ISs to colonize a chromosome from a phylogenetically-distant organism, or if the strength of this interaction affects the transposition rate. Here we describe the proliferation of a member of the IS1634 family in Acidiphilium over ~600 generations of cultured growth. We demonstrate that the purified transposase binds to the β sliding clamp of Acidiphilium, Leptospirillum and E. coli. Further, we also demonstrate that the Acidiphilium IS1634 transposase binds to the archaeal sliding clamp (PCNA) from Methanosarcina, and that the transposase encoded by Methanosarcina IS1634 binds to Acidiphilium β. Finally, we demonstrate that increasing the strength of the interaction between β and transposase results in a higher transposition rate in vivo. Our results suggest that the interaction could determine the potential of ISs to be mobilized in bacterial populations and also their ability to proliferate within chromosomes.
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24
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Lo WS, Gasparich GE, Kuo CH. Found and Lost: The Fates of Horizontally Acquired Genes in Arthropod-Symbiotic Spiroplasma. Genome Biol Evol 2015; 7:2458-72. [PMID: 26254485 PMCID: PMC4607517 DOI: 10.1093/gbe/evv160] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Horizontal gene transfer (HGT) is an important mechanism that contributed to biological diversity, particularly in bacteria. Through acquisition of novel genes, the recipient cell may change its ecological preference and the process could promote speciation. In this study, we determined the complete genome sequence of two Spiroplasma species for comparative analyses and inferred the putative gene gains and losses. Although most Spiroplasma species are symbionts of terrestrial insects, Spiroplasma eriocheiris has evolved to be a lethal pathogen of freshwater crustaceans. We found that approximately 7% of the genes in this genome may have originated from HGT and these genes expanded the metabolic capacity of this organism. Through comparison with the closely related Spiroplasma atrichopogonis, as well as other more divergent lineages, our results indicated that these HGT events could be traced back to the most recent common ancestor of these two species. However, most of these horizontally acquired genes have been pseudogenized in S. atrichopogonis, suggesting that they did not contribute to the fitness of this lineage that maintained the association with terrestrial insects. Thus, accumulation of small deletions that disrupted these foreign genes was not countered by natural selection. On the other hand, the long-term survival of these horizontally acquired genes in the S. eriocheiris genome hinted that they might play a role in the ecological shift of this species. Finally, the implications of these findings and the conflicts among gene content, 16S rRNA gene sequencing, and serological typing, are discussed in light of defining bacterial species.
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Affiliation(s)
- Wen-Sui Lo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, NationalChung Hsing University and Academia Sinica, Taipei, Taiwan Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | | | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, NationalChung Hsing University and Academia Sinica, Taipei, Taiwan Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
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25
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Abstract
ABSTRACT
The family
Bacillaceae
constitutes a phenotypically diverse and globally ubiquitous assemblage of bacteria. Investigation into how evolution has shaped, and continues to shape, this family has relied on several widely ranging approaches from classical taxonomy, ecological field studies, and evolution in soil microcosms to genomic-scale phylogenetics, laboratory, and directed evolution experiments. One unifying characteristic of the
Bacillaceae
, the endospore, poses unique challenges to answering questions regarding both the calculation of evolutionary rates and claims of extreme longevity in ancient environmental samples.
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26
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Alphaproteobacteria species as a source and target of lateral sequence transfers. Trends Microbiol 2014; 22:147-56. [DOI: 10.1016/j.tim.2013.12.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 12/05/2013] [Accepted: 12/17/2013] [Indexed: 11/22/2022]
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27
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The quest for a unified view of bacterial land colonization. ISME JOURNAL 2014; 8:1358-69. [PMID: 24451209 PMCID: PMC4069389 DOI: 10.1038/ismej.2013.247] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 11/15/2013] [Accepted: 12/12/2013] [Indexed: 12/13/2022]
Abstract
Exploring molecular mechanisms underlying bacterial water-to-land transition represents a critical start toward a better understanding of the functioning and stability of the terrestrial ecosystems. Here, we perform comprehensive analyses based on a large variety of bacteria by integrating taxonomic, phylogenetic and metagenomic data, in the quest for a unified view that elucidates genomic, evolutionary and ecological dynamics of the marine progenitors in adapting to nonaquatic environments. We hypothesize that bacterial land colonization is dominated by a single-gene sweep, that is, the emergence of dnaE2 derived from an early duplication event of the primordial dnaE, followed by a series of niche-specific genomic adaptations, including GC content increase, intensive horizontal gene transfer and constant genome expansion. In addition, early bacterial radiation may be stimulated by an explosion of land-borne hosts (for example, plants and animals) after initial land colonization events.
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28
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Boon E, Meehan CJ, Whidden C, Wong DHJ, Langille MGI, Beiko RG. Interactions in the microbiome: communities of organisms and communities of genes. FEMS Microbiol Rev 2014; 38:90-118. [PMID: 23909933 PMCID: PMC4298764 DOI: 10.1111/1574-6976.12035] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 07/02/2013] [Accepted: 07/10/2013] [Indexed: 12/17/2022] Open
Abstract
A central challenge in microbial community ecology is the delineation of appropriate units of biodiversity, which can be taxonomic, phylogenetic, or functional in nature. The term 'community' is applied ambiguously; in some cases, the term refers simply to a set of observed entities, while in other cases, it requires that these entities interact with one another. Microorganisms can rapidly gain and lose genes, potentially decoupling community roles from taxonomic and phylogenetic groupings. Trait-based approaches offer a useful alternative, but many traits can be defined based on gene functions, metabolic modules, and genomic properties, and the optimal set of traits to choose is often not obvious. An analysis that considers taxon assignment and traits in concert may be ideal, with the strengths of each approach offsetting the weaknesses of the other. Individual genes also merit consideration as entities in an ecological analysis, with characteristics such as diversity, turnover, and interactions modeled using genes rather than organisms as entities. We identify some promising avenues of research that are likely to yield a deeper understanding of microbial communities that shift from observation-based questions of 'Who is there?' and 'What are they doing?' to the mechanistically driven question of 'How will they respond?'
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Affiliation(s)
- Eva Boon
- Department of Biology, Dalhousie University, Halifax, NS, Canada
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EGN: a wizard for construction of gene and genome similarity networks. BMC Evol Biol 2013; 13:146. [PMID: 23841456 PMCID: PMC3727994 DOI: 10.1186/1471-2148-13-146] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/05/2013] [Indexed: 01/11/2023] Open
Abstract
Background Increasingly, similarity networks are being used for evolutionary analyses of molecular datasets. These networks are very useful, in particular for the analysis of gene sharing, lateral gene transfer and for the detection of distant homologs. Currently, such analyses require some computer programming skills due to the limited availability of user-friendly freely distributed software. Consequently, although appealing, the construction and analyses of these networks remain less familiar to biologists than do phylogenetic approaches. Results In order to ease the use of similarity networks in the community of evolutionary biologists, we introduce a software program, EGN, that runs under Linux or MacOSX. EGN automates the reconstruction of gene and genome networks from nucleic and proteic sequences. EGN also implements statistics describing genetic diversity in these samples, for various user-defined thresholds of similarities. In the interest of studying the complexity of evolutionary processes affecting microbial evolution, we applied EGN to a dataset of 571,044 proteic sequences from the three domains of life and from mobile elements. We observed that, in Borrelia, plasmids play a different role than in most other eubacteria. Rather than being genetic couriers involved in lateral gene transfer, Borrelia’s plasmids and their genes act as private genetic goods, that contribute to the creation of genetic diversity within their parasitic hosts. Conclusion EGN can be used for constructing, analyzing, and mining molecular datasets in evolutionary studies. The program can help increase our knowledge of the processes through which genes from distinct sources and/or from multiple genomes co-evolve in lineages of cellular organisms.
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Dahle H, Roalkvam I, Thorseth IH, Pedersen RB, Steen IH. The versatile in situ gene expression of an Epsilonproteobacteria-dominated biofilm from a hydrothermal chimney. ENVIRONMENTAL MICROBIOLOGY REPORTS 2013; 5:282-290. [PMID: 23584970 DOI: 10.1111/1758-2229.12016] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 10/03/2012] [Accepted: 11/05/2012] [Indexed: 06/02/2023]
Abstract
The Epsilonproteobacteria, including members of the genus Sulfurovum, are regarded as important primary producers in hydrothermal systems. However, their in situ gene expression in this habitat has so far not been investigated. We report a metatranscriptomic analysis of a Sulfurovum-dominated biofilm from one of the chimneys at the Loki's Castle hydrothermal system, located at the Arctic Mid Ocean Ridge. Transcripts involved in hydrogen oxidation, oxidation of sulfur species, aerobic respiration and denitrification were abundant and mostly assigned to Sulfurovum, indicating that members of this genus utilize multiple chemical energy sources simultaneously for primary production. Sulfurovum also seemed to have a diverse expression of transposases, potentially involved in horizontal gene transfer. Other transcripts were involved in CO₂ fixation by the reverse TCA cycle, the CRISPR-Cas system, heavy metal resistance, and sensing and responding to changing environmental conditions. Through pyrosequencing of PCR amplified 16S rRNA genes, the Sulfurovum-dominated biofilm was compared with another biofilm from the same chimney, revealing a large shift in the community structure of Epsilonproteobacteria-dominated biofilms over a few metres.
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Affiliation(s)
- Håkon Dahle
- Department of Biology, Centre for Geobiology, University of Bergen, Norway.
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TnpPred: A Web Service for the Robust Prediction of Prokaryotic Transposases. Comp Funct Genomics 2012; 2012:678761. [PMID: 23251097 PMCID: PMC3506888 DOI: 10.1155/2012/678761] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 08/20/2012] [Accepted: 09/18/2012] [Indexed: 11/18/2022] Open
Abstract
Transposases (Tnps) are enzymes that participate in the movement of insertion sequences (ISs) within and between genomes. Genes
that encode Tnps are amongst the most abundant and widely distributed genes in nature. However, they are difficult to
predict bioinformatically and given the increasing availability of prokaryotic genomes and metagenomes, it is incumbent to develop
rapid, high quality automatic annotation of ISs. This need prompted us to develop a web service, termed TnpPred for Tnp
discovery. It provides better sensitivity and specificity for Tnp predictions than given by currently available programs as
determined by ROC analysis. TnpPred should be useful for improving genome annotation. The TnpPred web service is freely available for
noncommercial use.
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Elhai J, Liu H, Taton A. Detection of horizontal transfer of individual genes by anomalous oligomer frequencies. BMC Genomics 2012; 13:245. [PMID: 22702893 PMCID: PMC3497702 DOI: 10.1186/1471-2164-13-245] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 05/18/2012] [Indexed: 11/10/2022] Open
Abstract
Background Understanding the history of life requires that we understand the transfer of genetic material across phylogenetic boundaries. Detecting genes that were acquired by means other than vertical descent is a basic step in that process. Detection by discordant phylogenies is computationally expensive and not always definitive. Many have used easily computed compositional features as an alternative procedure. However, different compositional methods produce different predictions, and the effectiveness of any method is not well established. Results The ability of octamer frequency comparisons to detect genes artificially seeded in cyanobacterial genomes was markedly increased by using as a training set those genes that are highly conserved over all bacteria. Using a subset of octamer frequencies in such tests also increased effectiveness, but this depended on the specific target genome and the source of the contaminating genes. The presence of high frequency octamers and the GC content of the contaminating genes were important considerations. A method comprising best practices from these tests was devised, the Core Gene Similarity (CGS) method, and it performed better than simple octamer frequency analysis, codon bias, or GC contrasts in detecting seeded genes or naturally occurring transposons. From a comparison of predictions with phylogenetic trees, it appears that the effectiveness of the method is confined to horizontal transfer events that have occurred recently in evolutionary time. Conclusions The CGS method may be an improvement over existing surrogate methods to detect genes of foreign origin.
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Affiliation(s)
- Jeff Elhai
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA 23284, USA.
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Schmitz-Esser S, Penz T, Spang A, Horn M. A bacterial genome in transition--an exceptional enrichment of IS elements but lack of evidence for recent transposition in the symbiont Amoebophilus asiaticus. BMC Evol Biol 2011; 11:270. [PMID: 21943072 PMCID: PMC3196728 DOI: 10.1186/1471-2148-11-270] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 09/26/2011] [Indexed: 11/18/2022] Open
Abstract
Background Insertion sequence (IS) elements are important mediators of genome plasticity and are widespread among bacterial and archaeal genomes. The 1.88 Mbp genome of the obligate intracellular amoeba symbiont Amoebophilus asiaticus contains an unusually large number of transposase genes (n = 354; 23% of all genes). Results The transposase genes in the A. asiaticus genome can be assigned to 16 different IS elements termed ISCaa1 to ISCaa16, which are represented by 2 to 24 full-length copies, respectively. Despite this high IS element load, the A. asiaticus genome displays a GC skew pattern typical for most bacterial genomes, indicating that no major rearrangements have occurred recently. Additionally, the high sequence divergence of some IS elements, the high number of truncated IS element copies (n = 143), as well as the absence of direct repeats in most IS elements suggest that the IS elements of A. asiaticus are transpositionally inactive. Although we could show transcription of 13 IS elements, we did not find experimental evidence for transpositional activity, corroborating our results from sequence analyses. However, we detected contiguous transcripts between IS elements and their downstream genes at nine loci in the A. asiaticus genome, indicating that some IS elements influence the transcription of downstream genes, some of which might be important for host cell interaction. Conclusions Taken together, the IS elements in the A. asiaticus genome are currently in the process of degradation and largely represent reflections of the evolutionary past of A. asiaticus in which its genome was shaped by their activity.
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Affiliation(s)
- Stephan Schmitz-Esser
- Department of Microbial Ecology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
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Williams D, Fournier GP, Lapierre P, Swithers KS, Green AG, Andam CP, Gogarten JP. A rooted net of life. Biol Direct 2011; 6:45. [PMID: 21936906 PMCID: PMC3189188 DOI: 10.1186/1745-6150-6-45] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 09/21/2011] [Indexed: 01/29/2023] Open
Abstract
Abstract Phylogenetic reconstruction using DNA and protein sequences has allowed the reconstruction of evolutionary histories encompassing all life. We present and discuss a means to incorporate much of this rich narrative into a single model that acknowledges the discrete evolutionary units that constitute the organism. Briefly, this Rooted Net of Life genome phylogeny is constructed around an initial, well resolved and rooted tree scaffold inferred from a supermatrix of combined ribosomal genes. Extant sampled ribosomes form the leaves of the tree scaffold. These leaves, but not necessarily the deeper parts of the scaffold, can be considered to represent a genome or pan-genome, and to be associated with members of other gene families within that sequenced (pan)genome. Unrooted phylogenies of gene families containing four or more members are reconstructed and superimposed over the scaffold. Initially, reticulations are formed where incongruities between topologies exist. Given sufficient evidence, edges may then be differentiated as those representing vertical lines of inheritance within lineages and those representing horizontal genetic transfers or endosymbioses between lineages. Reviewers W. Ford Doolittle, Eric Bapteste and Robert Beiko.
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Affiliation(s)
- David Williams
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269-3125, USA.
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Skippington E, Ragan MA. Lateral genetic transfer and the construction of genetic exchange communities. FEMS Microbiol Rev 2011; 35:707-35. [DOI: 10.1111/j.1574-6976.2010.00261.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Burke C, Steinberg P, Rusch D, Kjelleberg S, Thomas T. Bacterial community assembly based on functional genes rather than species. Proc Natl Acad Sci U S A 2011; 108:14288-93. [PMID: 21825123 PMCID: PMC3161577 DOI: 10.1073/pnas.1101591108] [Citation(s) in RCA: 472] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The principles underlying the assembly and structure of complex microbial communities are an issue of long-standing concern to the field of microbial ecology. We previously analyzed the community membership of bacterial communities associated with the green macroalga Ulva australis, and proposed a competitive lottery model for colonization of the algal surface in an attempt to explain the surprising lack of similarity in species composition across different algal samples. Here we extend the previous study by investigating the link between community structure and function in these communities, using metagenomic sequence analysis. Despite the high phylogenetic variability in microbial species composition on different U. australis (only 15% similarity between samples), similarity in functional composition was high (70%), and a core of functional genes present across all algal-associated communities was identified that were consistent with the ecology of surface- and host-associated bacteria. These functions were distributed widely across a variety of taxa or phylogenetic groups. This observation of similarity in habitat (niche) use with respect to functional genes, but not species, together with the relative ease with which bacteria share genetic material, suggests that the key level at which to address the assembly and structure of bacterial communities may not be "species" (by means of rRNA taxonomy), but rather the more functional level of genes.
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Affiliation(s)
- Catherine Burke
- School of Biotechnology and Biomolecular Sciences
- The iThree Institute, University of Technology, Ultimo, New South Wales 2007, Australia
| | - Peter Steinberg
- School of Biological, Earth and Environmental Sciences, Centre for Marine Bio-Innovation, University of New South Wales, Sydney, New South Wales 2052, Australia
- Sydney Institute of Marine Science, Mosman, New South Wales 2088, Australia
| | - Doug Rusch
- The J. Craig Venter Institute, Rockville, MD 20850; and
| | - Staffan Kjelleberg
- School of Biotechnology and Biomolecular Sciences
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
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Popa O, Dagan T. Trends and barriers to lateral gene transfer in prokaryotes. Curr Opin Microbiol 2011; 14:615-23. [PMID: 21856213 DOI: 10.1016/j.mib.2011.07.027] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 07/19/2011] [Accepted: 07/25/2011] [Indexed: 11/19/2022]
Abstract
Gene acquisition by lateral gene transfer (LGT) is an important mechanism for natural variation among prokaryotes. Laboratory experiments show that protein-coding genes can be laterally transferred extremely fast among microbial cells, inherited to most of their descendants, and adapt to a new regulatory regime within a short time. Recent advance in the phylogenetic analysis of microbial genomes using networks approach reveals a substantial impact of LGT during microbial genome evolution. Phylogenomic networks of LGT among prokaryotes reconstructed from completely sequenced genomes uncover barriers to LGT in multiple levels. Here we discuss the kinds of barriers to gene acquisition in nature including physical barriers for gene transfer between cells, genomic barriers for the integration of acquired DNA, and functional barriers for the acquisition of new genes.
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Affiliation(s)
- Ovidiu Popa
- Institute of Molecular Evolution, Heinrich-Heine University of Düsseldorf, Universitätstr. 1 40225, Düsseldorf, Germany
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Phylogenomic networks. Trends Microbiol 2011; 19:483-91. [PMID: 21820313 DOI: 10.1016/j.tim.2011.07.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 07/04/2011] [Accepted: 07/08/2011] [Indexed: 01/15/2023]
Abstract
Phylogenomics is aimed at studying functional and evolutionary aspects of genome biology using phylogenetic analysis of whole genomes. Current approaches to genome phylogenies are commonly founded in terms of phylogenetic trees. However, several evolutionary processes are non tree-like in nature, including recombination and lateral gene transfer (LGT). Phylogenomic networks are a special type of phylogenetic network reconstructed from fully sequenced genomes. The network model, comprising genomes connected by pairwise evolutionary relations, enables the reconstruction of both vertical and LGT events. Modeling genome evolution in the form of a network enables the use of an extensive toolbox developed for network research. The structural properties of phylogenomic networks open up fundamentally new insights into genome evolution.
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Tarrío R, Ayala FJ, Rodríguez-Trelles F. The Vein Patterning 1 (VEP1) gene family laterally spread through an ecological network. PLoS One 2011; 6:e22279. [PMID: 21818306 PMCID: PMC3144213 DOI: 10.1371/journal.pone.0022279] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Accepted: 06/18/2011] [Indexed: 11/23/2022] Open
Abstract
Lateral gene transfer (LGT) is a major evolutionary mechanism in prokaryotes. Knowledge about LGT— particularly, multicellular— eukaryotes has only recently started to accumulate. A widespread assumption sees the gene as the unit of LGT, largely because little is yet known about how LGT chances are affected by structural/functional features at the subgenic level. Here we trace the evolutionary trajectory of VEin Patterning 1, a novel gene family known to be essential for plant development and defense. At the subgenic level VEP1 encodes a dinucleotide-binding Rossmann-fold domain, in common with members of the short-chain dehydrogenase/reductase (SDR) protein family. We found: i) VEP1 likely originated in an aerobic, mesophilic and chemoorganotrophic α-proteobacterium, and was laterally propagated through nets of ecological interactions, including multiple LGTs between phylogenetically distant green plant/fungi-associated bacteria, and five independent LGTs to eukaryotes. Of these latest five transfers, three are ancient LGTs, implicating an ancestral fungus, the last common ancestor of land plants and an ancestral trebouxiophyte green alga, and two are recent LGTs to modern embryophytes. ii) VEP1's rampant LGT behavior was enabled by the robustness and broad utility of the dinucleotide-binding Rossmann-fold, which provided a platform for the evolution of two unprecedented departures from the canonical SDR catalytic triad. iii) The fate of VEP1 in eukaryotes has been different in different lineages, being ubiquitous and highly conserved in land plants, whereas fungi underwent multiple losses. And iv) VEP1-harboring bacteria include non-phytopathogenic and phytopathogenic symbionts which are non-randomly distributed with respect to the type of harbored VEP1 gene. Our findings suggest that VEP1 may have been instrumental for the evolutionary transition of green plants to land, and point to a LGT-mediated ‘Trojan Horse’ mechanism for the evolution of bacterial pathogenesis against plants. VEP1 may serve as tool for revealing microbial interactions in plant/fungi-associated environments.
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Affiliation(s)
- Rosa Tarrío
- Universidad de Santiago de Compostela, CIBERER, Genome Medicine Group, Santiago de Compostela, Spain
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, California, United States of America
| | - Francisco J. Ayala
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, California, United States of America
| | - Francisco Rodríguez-Trelles
- Grup de Biologia Evolutiva, Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Barcelona, Spain
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, California, United States of America
- * E-mail:
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Everything at once: comparative analysis of the genomes of bacterial pathogens. Vet Microbiol 2011; 153:13-26. [PMID: 21764529 DOI: 10.1016/j.vetmic.2011.06.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Revised: 06/15/2011] [Accepted: 06/16/2011] [Indexed: 12/12/2022]
Abstract
The sum of unique genes in all genomes of a bacterial species is referred to as the pan-genome and is comprised of variably absent or present accessory genes and universally present core genes. The accessory genome is an important source of genetic variability in bacterial populations, allowing sub-populations of bacteria to better adapt to specific niches. Such subgroups may themselves have a relatively stable core genome that may influence host preference, virulence, or an association with specific disease syndromes. The core genome provides a useful means of phylogenetic reconstruction as well as contributing to phenotypic heterogeneity. Variation within the pan-genome forms the basis of comparative genotyping techniques, which have evolved alongside technology. Current high-throughput sequencing platforms have created an unprecedented opportunity for comparisons among multiple, closely related genomes. The computer algorithms and software for such comparisons continue to evolve and promise exciting advances in the world of bacterial comparative genomics. We review genotyping techniques based upon phenotypic traits, both core and accessory genomes, and look at some of the software programs currently available to perform whole-genome comparative analyses.
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Liu X, Wan L, Li J, Reinert G, Waterman MS, Sun F. New powerful statistics for alignment-free sequence comparison under a pattern transfer model. J Theor Biol 2011; 284:106-16. [PMID: 21723298 DOI: 10.1016/j.jtbi.2011.06.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 05/30/2011] [Accepted: 06/17/2011] [Indexed: 12/15/2022]
Abstract
Alignment-free sequence comparison is widely used for comparing gene regulatory regions and for identifying horizontally transferred genes. Recent studies on the power of a widely used alignment-free comparison statistic D2 and its variants D*2 and D(s)2 showed that their power approximates a limit smaller than 1 as the sequence length tends to infinity under a pattern transfer model. We develop new alignment-free statistics based on D2, D*2 and D(s)2 by comparing local sequence pairs and then summing over all the local sequence pairs of certain length. We show that the new statistics are much more powerful than the corresponding statistics and the power tends to 1 as the sequence length tends to infinity under the pattern transfer model.
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Affiliation(s)
- Xuemei Liu
- School of Physics, South China University of Technology, Guangzhou, PR China
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Schliep K, Lopez P, Lapointe FJ, Bapteste E. Harvesting evolutionary signals in a forest of prokaryotic gene trees. Mol Biol Evol 2010; 28:1393-405. [PMID: 21172835 DOI: 10.1093/molbev/msq323] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Phylogenomic studies produce increasingly large phylogenetic forests of trees with patchy taxonomical sampling. Typically, prokaryotic data generate thousands of gene trees of all sizes that are difficult, if not impossible, to root. Their topologies do not match the genealogy of lineages, as they are influenced not only by duplication, losses, and vertical descent but also by lateral gene transfer (LGT) and recombination. Because this complexity in part reflects the diversity of evolutionary processes, the study of phylogenetic forests is thus a great opportunity to improve our understanding of prokaryotic evolution. Here, we show how the rich evolutionary content of such novel phylogenetic objects can be exploited through the development of new approaches designed specifically for extracting the multiple evolutionary signals present in the forest of life, that is, by slicing up trees into remarkable bits and pieces: clans, slices, and clips. We harvested a forest of 6,901 unrooted gene trees comprising up to 100 prokaryotic genomes (41 archaea and 59 bacteria) to search for evolutionary events that a species tree would not account for. We identified 1) trees and partitions of trees that reflected the lifestyle of organisms rather than their taxonomy, 2) candidate lifestyle-specific genetic modules, used by distinct unrelated organisms to adapt to the same environment, 3) gene families, nonrandomly distributed in the functional space, that were frequently exchanged between archaea and bacteria, sometimes without major changes in their sequences. Finally, 4) we reconstructed polarized networks of genetic partnerships between archaea and bacteria to describe some of the rules affecting LGT between these two Domains.
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Affiliation(s)
- Klaus Schliep
- UMR CNRS 7138 Systématique, Adaptation, Evolution, Muséum National d'Histoire Naturelle, Paris, France
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Fondi M, Fani R. The horizontal flow of the plasmid resistome: clues from inter-generic similarity networks. Environ Microbiol 2010; 12:3228-42. [DOI: 10.1111/j.1462-2920.2010.02295.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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45
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The delta subunit of RNA polymerase, RpoE, is a global modulator of Streptococcus mutans environmental adaptation. J Bacteriol 2010; 192:5081-92. [PMID: 20675470 DOI: 10.1128/jb.00653-10] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The delta subunit of RNA polymerase, RpoE, is widespread in low-G+C Gram-positive bacteria and is thought to play a role in enhancing transcriptional specificity by blocking RNA polymerase binding at weak promoter sites and stimulating RNA synthesis by accelerating core enzyme recycling. Despite the well-studied biochemical properties of RpoE, a role for this protein in vivo has not been defined in depth. In this study, we show that inactivation of rpoE in the human dental caries pathogen Streptococcus mutans causes impaired growth and loss of important virulence traits, including biofilm formation, resistance to antibiotics, and tolerance to environmental stresses. Complementation of the mutant with rpoE expressed in trans restored its phenotype to wild type. The luciferase fusion reporter showed that rpoE was highly transcribed throughout growth and that acid and hydrogen peroxide stresses repressed rpoE expression. Transcriptome profiling of wild-type and ΔrpoE cells in the exponential and early stationary phase of growth, under acid and hydrogen peroxide stress and under both stresses combined, revealed that genes involved in histidine synthesis, malolactic fermentation, biofilm formation, and antibiotic resistance were downregulated in the ΔrpoE mutant under all conditions. Moreover, the loss of RpoE resulted in dramatic changes in transport and metabolism of carbohydrates and amino acids. Interestingly, differential expression, mostly upregulation, of 330 noncoding regions was found. In conclusion, this study demonstrates that RpoE is an important global modulator of gene expression in S. mutans which is required for optimal growth and environmental adaptation.
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46
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Aziz RK, Breitbart M, Edwards RA. Transposases are the most abundant, most ubiquitous genes in nature. Nucleic Acids Res 2010; 38:4207-17. [PMID: 20215432 PMCID: PMC2910039 DOI: 10.1093/nar/gkq140] [Citation(s) in RCA: 198] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Genes, like organisms, struggle for existence, and the most successful genes persist and widely disseminate in nature. The unbiased determination of the most successful genes requires access to sequence data from a wide range of phylogenetic taxa and ecosystems, which has finally become achievable thanks to the deluge of genomic and metagenomic sequences. Here, we analyzed 10 million protein-encoding genes and gene tags in sequenced bacterial, archaeal, eukaryotic and viral genomes and metagenomes, and our analysis demonstrates that genes encoding transposases are the most prevalent genes in nature. The finding that these genes, classically considered as selfish genes, outnumber essential or housekeeping genes suggests that they offer selective advantage to the genomes and ecosystems they inhabit, a hypothesis in agreement with an emerging body of literature. Their mobile nature not only promotes dissemination of transposable elements within and between genomes but also leads to mutations and rearrangements that can accelerate biological diversification and—consequently—evolution. By securing their own replication and dissemination, transposases guarantee to thrive so long as nucleic acid-based life forms exist.
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Affiliation(s)
- Ramy K Aziz
- Computation Institute, University of Chicago, Chicago, IL 60637, USA.
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47
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Freilich S, Kreimer A, Meilijson I, Gophna U, Sharan R, Ruppin E. The large-scale organization of the bacterial network of ecological co-occurrence interactions. Nucleic Acids Res 2010; 38:3857-68. [PMID: 20194113 PMCID: PMC2896517 DOI: 10.1093/nar/gkq118] [Citation(s) in RCA: 174] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In their natural environments, microorganisms form complex systems of interactions. Understating the structure and organization of bacterial communities is likely to have broad medical and ecological consequences, yet a comprehensive description of the network of environmental interactions is currently lacking. Here, we mine co-occurrences in the scientific literature to construct such a network and demonstrate an expected pattern of association between the species' lifestyle and the recorded number of co-occurring partners. We further focus on the well-annotated gut community and show that most co-occurrence interactions of typical gut bacteria occur within this community. The network is then clustered into species-groups that significantly correspond with natural occurring communities. The relationships between resource competition, metabolic yield and growth rate within the clusters correspond with the r/K selection theory. Overall, these results support the constructed clusters as a first approximation of a bacterial ecosystem model. This comprehensive collection of predicted communities forms a new data resource for further systematic characterization of the ecological design principals shaping communities. Here, we demonstrate its utility for predicting cooperation and inhibition within communities.
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Affiliation(s)
- Shiri Freilich
- Blavatnik School of Computer Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel.
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