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Luan T, Commichaux S, Hoffmann M, Jayeola V, Jang JH, Pop M, Rand H, Luo Y. Benchmarking short and long read polishing tools for nanopore assemblies: achieving near-perfect genomes for outbreak isolates. BMC Genomics 2024; 25:679. [PMID: 38978005 PMCID: PMC11232133 DOI: 10.1186/s12864-024-10582-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 07/01/2024] [Indexed: 07/10/2024] Open
Abstract
BACKGROUND Oxford Nanopore provides high throughput sequencing platforms able to reconstruct complete bacterial genomes with 99.95% accuracy. However, even small levels of error can obscure the phylogenetic relationships between closely related isolates. Polishing tools have been developed to correct these errors, but it is uncertain if they obtain the accuracy needed for the high-resolution source tracking of foodborne illness outbreaks. RESULTS We tested 132 combinations of assembly and short- and long-read polishing tools to assess their accuracy for reconstructing the genome sequences of 15 highly similar Salmonella enterica serovar Newport isolates from a 2020 onion outbreak. While long-read polishing alone improved accuracy, near perfect accuracy (99.9999% accuracy or ~ 5 nucleotide errors across the 4.8 Mbp genome, excluding low confidence regions) was only obtained by pipelines that combined both long- and short-read polishing tools. Notably, medaka was a more accurate and efficient long-read polisher than Racon. Among short-read polishers, NextPolish showed the highest accuracy, but Pilon, Polypolish, and POLCA performed similarly. Among the 5 best performing pipelines, polishing with medaka followed by NextPolish was the most common combination. Importantly, the order of polishing tools mattered i.e., using less accurate tools after more accurate ones introduced errors. Indels in homopolymers and repetitive regions, where the short reads could not be uniquely mapped, remained the most challenging errors to correct. CONCLUSIONS Short reads are still needed to correct errors in nanopore sequenced assemblies to obtain the accuracy required for source tracking investigations. Our granular assessment of the performance of the polishing pipelines allowed us to suggest best practices for tool users and areas for improvement for tool developers.
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Affiliation(s)
- Tu Luan
- Department of Computer Science, University of Maryland, College Park, MD, 20742, USA
| | - Seth Commichaux
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, Laurel, MD, 20708, USA.
| | - Maria Hoffmann
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD, 20740, USA
| | - Victor Jayeola
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD, 20740, USA
| | - Jae Hee Jang
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD, 20740, USA
| | - Mihai Pop
- Department of Computer Science, University of Maryland, College Park, MD, 20742, USA
| | - Hugh Rand
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD, 20740, USA
| | - Yan Luo
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD, 20740, USA
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2
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Ludwig J, Mrázek J. OrthoRefine: automated enhancement of prior ortholog identification via synteny. BMC Bioinformatics 2024; 25:163. [PMID: 38664637 PMCID: PMC11044567 DOI: 10.1186/s12859-024-05786-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 04/15/2024] [Indexed: 04/29/2024] Open
Abstract
BACKGROUND Identifying orthologs continues to be an early and imperative step in genome analysis but remains a challenging problem. While synteny (conservation of gene order) has previously been used independently and in combination with other methods to identify orthologs, applying synteny in ortholog identification has yet to be automated in a user-friendly manner. This desire for automation and ease-of-use led us to develop OrthoRefine, a standalone program that uses synteny to refine ortholog identification. RESULTS We developed OrthoRefine to improve the detection of orthologous genes by implementing a look-around window approach to detect synteny. We tested OrthoRefine in tandem with OrthoFinder, one of the most used software for identification of orthologs in recent years. We evaluated improvements provided by OrthoRefine in several bacterial and a eukaryotic dataset. OrthoRefine efficiently eliminates paralogs from orthologous groups detected by OrthoFinder. Using synteny increased specificity and functional ortholog identification; additionally, analysis of BLAST e-value, phylogenetics, and operon occurrence further supported using synteny for ortholog identification. A comparison of several window sizes suggested that smaller window sizes (eight genes) were generally the most suitable for identifying orthologs via synteny. However, larger windows (30 genes) performed better in datasets containing less closely related genomes. A typical run of OrthoRefine with ~ 10 bacterial genomes can be completed in a few minutes on a regular desktop PC. CONCLUSION OrthoRefine is a simple-to-use, standalone tool that automates the application of synteny to improve ortholog detection. OrthoRefine is particularly efficient in eliminating paralogs from orthologous groups delineated by standard methods.
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Affiliation(s)
- J Ludwig
- Institute of Bioinformatics, The University of Georgia, Athens, GA, 30602, USA.
| | - J Mrázek
- Department of Microbiology and Institute of Bioinformatics, The University of Georgia, Athens, GA, 30602, USA
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3
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Hwang Y, Cornman AL, Kellogg EH, Ovchinnikov S, Girguis PR. Genomic language model predicts protein co-regulation and function. Nat Commun 2024; 15:2880. [PMID: 38570504 PMCID: PMC10991518 DOI: 10.1038/s41467-024-46947-9] [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: 05/30/2023] [Accepted: 03/13/2024] [Indexed: 04/05/2024] Open
Abstract
Deciphering the relationship between a gene and its genomic context is fundamental to understanding and engineering biological systems. Machine learning has shown promise in learning latent relationships underlying the sequence-structure-function paradigm from massive protein sequence datasets. However, to date, limited attempts have been made in extending this continuum to include higher order genomic context information. Evolutionary processes dictate the specificity of genomic contexts in which a gene is found across phylogenetic distances, and these emergent genomic patterns can be leveraged to uncover functional relationships between gene products. Here, we train a genomic language model (gLM) on millions of metagenomic scaffolds to learn the latent functional and regulatory relationships between genes. gLM learns contextualized protein embeddings that capture the genomic context as well as the protein sequence itself, and encode biologically meaningful and functionally relevant information (e.g. enzymatic function, taxonomy). Our analysis of the attention patterns demonstrates that gLM is learning co-regulated functional modules (i.e. operons). Our findings illustrate that gLM's unsupervised deep learning of the metagenomic corpus is an effective and promising approach to encode functional semantics and regulatory syntax of genes in their genomic contexts and uncover complex relationships between genes in a genomic region.
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Affiliation(s)
- Yunha Hwang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA.
| | | | - Elizabeth H Kellogg
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Sergey Ovchinnikov
- John Harvard Distinguished Science Fellowship Program, Harvard University, Cambridge, MA, USA.
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Peter R Girguis
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA.
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4
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Genetic and Structural Diversity of Prokaryotic Ice-Binding Proteins from the Central Arctic Ocean. Genes (Basel) 2023; 14:genes14020363. [PMID: 36833289 PMCID: PMC9957290 DOI: 10.3390/genes14020363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 02/01/2023] Open
Abstract
Ice-binding proteins (IBPs) are a group of ecologically and biotechnologically relevant enzymes produced by psychrophilic organisms. Although putative IBPs containing the domain of unknown function (DUF) 3494 have been identified in many taxa of polar microbes, our knowledge of their genetic and structural diversity in natural microbial communities is limited. Here, we used samples from sea ice and sea water collected in the central Arctic Ocean as part of the MOSAiC expedition for metagenome sequencing and the subsequent analyses of metagenome-assembled genomes (MAGs). By linking structurally diverse IBPs to particular environments and potential functions, we reveal that IBP sequences are enriched in interior ice, have diverse genomic contexts and cluster taxonomically. Their diverse protein structures may be a consequence of domain shuffling, leading to variable combinations of protein domains in IBPs and probably reflecting the functional versatility required to thrive in the extreme and variable environment of the central Arctic Ocean.
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5
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Botas J, Rodríguez Del Río Á, Giner-Lamia J, Huerta-Cepas J. GeCoViz: genomic context visualisation of prokaryotic genes from a functional and evolutionary perspective. Nucleic Acids Res 2022; 50:W352-W357. [PMID: 35639770 PMCID: PMC9252766 DOI: 10.1093/nar/gkac367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/14/2022] [Accepted: 05/05/2022] [Indexed: 11/14/2022] Open
Abstract
Synteny conservation analysis is a well-established methodology to investigate the potential functional role of unknown prokaryotic genes. However, bioinformatic tools to reconstruct and visualise genomic contexts usually depend on slow computations, are restricted to narrow taxonomic ranges, and/or do not allow for the functional and interactive exploration of neighbouring genes across different species. Here, we present GeCoViz, an online resource built upon 12 221 reference prokaryotic genomes that provides fast and interactive visualisation of custom genomic regions anchored by any target gene, which can be sought by either name, orthologous group (KEGGs, eggNOGs), protein domain (PFAM) or sequence. To facilitate functional and evolutionary interpretation, GeCoViz allows to customise the taxonomic scope of each analysis and provides comprehensive annotations of the neighbouring genes. Interactive visualisation options include, among others, the scaled representations of gene lengths and genomic distances, and on the fly calculation of synteny conservation of neighbouring genes, which can be highlighted based on custom thresholds. The resulting plots can be downloaded as high-quality images for publishing purposes. Overall, GeCoViz offers an easy-to-use, comprehensive, fast and interactive web-based tool for investigating the genomic context of prokaryotic genes, and is freely available at https://gecoviz.cgmlab.org.
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Affiliation(s)
- Jorge Botas
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Campus de Montegancedo-UPM, Madrid, 28223, Spain
| | - Álvaro Rodríguez Del Río
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Campus de Montegancedo-UPM, Madrid, 28223, Spain
| | - Joaquín Giner-Lamia
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Campus de Montegancedo-UPM, Madrid, 28223, Spain.,Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), Madrid, 28040, Spain
| | - Jaime Huerta-Cepas
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Campus de Montegancedo-UPM, Madrid, 28223, Spain
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Javier RA, Matías R, Alonso F, Renato C, Gloria L. A novel gene from the acidophilic bacterium Leptospirillum sp. CF-1 and its role in oxidative stress and chromate tolerance. Biol Res 2022; 55:19. [PMID: 35525996 PMCID: PMC9080137 DOI: 10.1186/s40659-022-00388-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 04/15/2022] [Indexed: 11/16/2022] Open
Abstract
Background Acidophilic microorganisms like Leptospirillum sp. CF-1 thrive in environments with extremely low pH and high concentrations of dissolved heavy metals that can induce the generation of reactive oxygen species (ROS). Several hypothetical genes and proteins from Leptospirillum sp. CF-1 are known to be up-regulated under oxidative stress conditions. Results In the present work, the function of hypothetical gene ABH19_09590 from Leptospirillum sp. CF-1 was studied. Heterologous expression of this gene in Escherichia coli led to an increase in the ability to grow under oxidant conditions with 5 mM K2CrO4 or 5 mM H2O2. Similarly, a significant reduction in ROS production in E. coli transformed with a plasmid carrying ABH19_09590 was observed after exposure to these oxidative stress elicitors for 30 min, compared to a strain complemented with the empty vector. A co-transcriptional study using RT-PCR showed that ABH19_09590 is contained in an operon, here named the “och” operon, that also contains ABH19_09585, ABH19_09595 and ABH19_09600 genes. The expression of the och operon was significantly up-regulated in Leptospirillum sp. CF-1 exposed to 5 mM K2CrO4 for 15 and 30 min. Genes of this operon potentially encode a NADH:ubiquinone oxidoreductase, a CXXC motif-containing protein likely involved in thiol/disulfide exchange, a hypothetical protein, and a di-hydroxy-acid dehydratase. A comparative genomic analysis revealed that the och operon is a characteristic genetic determinant of the Leptospirillum genus that is not present in other acidophiles. Conclusions Altogether, these results suggest that the och operon plays a protective role against chromate and hydrogen peroxide and is an important mechanism required to face polyextremophilic conditions in acid environments.
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Affiliation(s)
- Rivera-Araya Javier
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile
| | - Riveros Matías
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile
| | - Ferrer Alonso
- Núcleo de Química y Bioquímica, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Chávez Renato
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile
| | - Levicán Gloria
- Biology Department, Faculty of Chemistry and Biology, University of Santiago of Chile (USACH), Santiago, Chile.
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7
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Genomic Characterization Provides an Insight into the Pathogenicity of the Poplar Canker Bacterium Lonsdalea populi. Genes (Basel) 2021; 12:genes12020246. [PMID: 33572241 PMCID: PMC7914447 DOI: 10.3390/genes12020246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 01/28/2021] [Accepted: 02/04/2021] [Indexed: 11/17/2022] Open
Abstract
An emerging poplar canker caused by the gram-negative bacterium, Lonsdalea populi, has led to high mortality of hybrid poplars Populus × euramericana in China and Europe. The molecular bases of pathogenicity and bark adaptation of L. populi have become a focus of recent research. This study revealed the whole genome sequence and identified putative virulence factors of L. populi. A high-quality L. populi genome sequence was assembled de novo, with a genome size of 3,859,707 bp, containing approximately 3434 genes and 107 RNAs (75 tRNA, 22 rRNA, and 10 ncRNA). The L. populi genome contained 380 virulence-associated genes, mainly encoding for adhesion, extracellular enzymes, secretory systems, and two-component transduction systems. The genome had 110 carbohydrate-active enzyme (CAZy)-coding genes and putative secreted proteins. The antibiotic-resistance database annotation listed that L. populi was resistant to penicillin, fluoroquinolone, and kasugamycin. Analysis of comparative genomics found that L. populi exhibited the highest homology with the L. britannica genome and L. populi encompassed 1905 specific genes, 1769 dispensable genes, and 1381 conserved genes, suggesting high evolutionary diversity and genomic plasticity. Moreover, the pan genome analysis revealed that the N-5-1 genome is an open genome. These findings provide important resources for understanding the molecular basis of the pathogenicity and biology of L. populi and the poplar-bacterium interaction.
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8
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Contributions of Microbial “Contact Leaching” to Pyrite Oxidation under Different Controlled Redox Potentials. MINERALS 2020. [DOI: 10.3390/min10100856] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The function of microbial contact leaching to pyrite oxidation was investigated by analyzing the differences of residue morphologies, leaching rates, surface products, and microbial consortia under different conditions in this study. This was achieved by novel equipment that can control the redox potential of the solution and isolate pyrite from microbial contact oxidation. The morphology of residues showed that the corrosions were a little bit severer in the presence of attached microbes under 750 mV and 850 mV (vs. SHE). At 650 mV, the oxidation of pyrite was undetectable even in the presence of attached microbes. The pyrite dissolution rate was higher with attached microbes than that without attached microbes at 750 mV and 850 mV. The elemental sulfur on the surface of pyrite residues with sessile microorganisms was much less than that without attached microbes at 750 mV and 850 mV, showing that sessile acidophiles may accelerate pyrite leaching by reducing the elemental sulfur inhibition. Many more sulfur-oxidizers were found in the sessile microbial consortium which also supported the idea. The results suggest that the microbial “contact leaching” to pyrite oxidation is limited and relies on the elimination of elemental sulfur passivation by attached sulfur-oxidizing microbes rather than the contact oxidation by EPS-Fe.
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9
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Guan Y, Ngugi DK, Vinu M, Blom J, Alam I, Guillot S, Ferry JG, Stingl U. Comparative Genomics of the Genus Methanohalophilus, Including a Newly Isolated Strain From Kebrit Deep in the Red Sea. Front Microbiol 2019; 10:839. [PMID: 31068917 PMCID: PMC6491703 DOI: 10.3389/fmicb.2019.00839] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 04/02/2019] [Indexed: 01/25/2023] Open
Abstract
Halophilic methanogens play an important role in the carbon cycle in hypersaline environments, but are under-represented in culture collections. In this study, we describe a novel Methanohalophilus strain that was isolated from the sulfide-rich brine-seawater interface of Kebrit Deep in the Red Sea. Based on physiological and phylogenomic features, strain RSK, which is the first methanogenic archaeon to be isolated from a deep hypersaline anoxic brine lake of the Red Sea, represents a novel species of this genus. In order to compare the genetic traits underpinning the adaptations of this genus in diverse hypersaline environments, we sequenced the genome of strain RSK and compared it with genomes of previously isolated and well characterized species in this genus (Methanohalophilus mahii, Methanohalophilus halophilus, Methanohalophilus portucalensis, and Methanohalophilus euhalobius). These analyses revealed a highly conserved genomic core of greater than 93% of annotated genes (1490 genes) containing pathways for methylotrophic methanogenesis, osmoprotection through salt-out strategy, and oxidative stress response, among others. Despite the high degree of genomic conservation, species-specific differences in sulfur and glycogen metabolisms, viral resistance, amino acid, and peptide uptake machineries were also evident. Thus, while Methanohalophilus species are found in diverse extreme environments, each genotype also possesses adaptive traits that are likely relevant in their respective hypersaline habitats.
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Affiliation(s)
- Yue Guan
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - David K. Ngugi
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Manikandan Vinu
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Jochen Blom
- Bioinformatik und Systembiologie, Justus-Liebig-Universität Giessen, Giessen, Germany
| | - Intikhab Alam
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Sylvain Guillot
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - James G. Ferry
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
| | - Ulrich Stingl
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Department of Microbiology and Cell Science, UF/IFAS Fort Lauderdale Research and Education Center, University of Florida, Davie, FL, United States
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10
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Freese HM, Sikorski J, Bunk B, Scheuner C, Meier-Kolthoff JP, Spröer C, Gram L, Overmann J. Trajectories and Drivers of Genome Evolution in Surface-Associated Marine Phaeobacter. Genome Biol Evol 2018; 9:3297-3311. [PMID: 29194520 PMCID: PMC5730936 DOI: 10.1093/gbe/evx249] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2017] [Indexed: 12/19/2022] Open
Abstract
The extent of genome divergence and the evolutionary events leading to speciation of marine bacteria have mostly been studied for (locally) abundant, free-living groups. The genus Phaeobacter is found on different marine surfaces, seems to occupy geographically disjunct habitats, and is involved in different biotic interactions, and was therefore targeted in the present study. The analysis of the chromosomes of 32 closely related but geographically spread Phaeobacter strains revealed an exceptionally large, highly syntenic core genome. The flexible gene pool is constantly but slightly expanding across all Phaeobacter lineages. The horizontally transferred genes mostly originated from bacteria of the Roseobacter group and horizontal transfer most likely was mediated by gene transfer agents. No evidence for geographic isolation and habitat specificity of the different phylogenomic Phaeobacter clades was detected based on the sources of isolation. In contrast, the functional gene repertoire and physiological traits of different phylogenomic Phaeobacter clades were sufficiently distinct to suggest an adaptation to an associated lifestyle with algae, to additional nutrient sources, or toxic heavy metals. Our study reveals that the evolutionary trajectories of surface-associated marine bacteria can differ significantly from free-living marine bacteria or marine generalists.
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Affiliation(s)
- Heike M Freese
- Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig, Germany
| | - Johannes Sikorski
- Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig, Germany
| | - Boyke Bunk
- Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig, Germany
| | - Carmen Scheuner
- Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig, Germany
| | - Jan P Meier-Kolthoff
- Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig, Germany
| | - Cathrin Spröer
- Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig, Germany
| | - Lone Gram
- Department of Biotechnology and Bioengineering, Technical University of Denmark, Lyngby, Denmark
| | - Jörg Overmann
- Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig, Germany.,Institute of Microbiology, University Braunschweig, Germany
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11
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Jun SR, Nookaew I, Hauser L, Gorin A. Assessment of genome annotation using gene function similarity within the gene neighborhood. BMC Bioinformatics 2017; 18:345. [PMID: 28724412 PMCID: PMC5517811 DOI: 10.1186/s12859-017-1761-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 07/13/2017] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Functional annotation of bacterial genomes is an obligatory and crucially important step of information processing from the genome sequences into cellular mechanisms. However, there is a lack of computational methods to evaluate the quality of functional assignments. RESULTS We developed a genome-scale model that assigns Bayesian probability to each gene utilizing a known property of functional similarity between neighboring genes in bacteria. CONCLUSIONS Our model clearly distinguished true annotation from random annotation with Bayesian annotation probability >0.95. Our model will provide a useful guide to quantitatively evaluate functional annotation methods and to detect gene sets with reliable annotations.
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Affiliation(s)
- Se-Ran Jun
- Department of Biomedical Informatics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205 USA
| | - Intawat Nookaew
- Department of Biomedical Informatics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205 USA
| | - Loren Hauser
- Comparative Genomics Group, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Andrey Gorin
- Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
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12
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Wegner CE, Liesack W. Unexpected Dominance of Elusive Acidobacteria in Early Industrial Soft Coal Slags. Front Microbiol 2017; 8:1023. [PMID: 28642744 PMCID: PMC5462947 DOI: 10.3389/fmicb.2017.01023] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 05/22/2017] [Indexed: 11/19/2022] Open
Abstract
Acid mine drainage (AMD) and mine tailing environments are well-characterized ecosystems known to be dominated by organisms involved in iron- and sulfur-cycling. Here we examined the microbiology of industrial soft coal slags that originate from alum leaching, an ecosystem distantly related to AMD environments. Our study involved geochemical analyses, bacterial community profiling, and shotgun metagenomics. The slags still contained high amounts of alum constituents (aluminum, sulfur), which mediated direct and indirect effects on bacterial community structure. Bacterial groups typically found in AMD systems and mine tailings were not present. Instead, the soft coal slags were dominated by uncharacterized groups of Acidobacteria (DA052 [subdivision 2], KF-JG30-18 [subdivision 13]), Actinobacteria (TM214), Alphaproteobacteria (DA111), and Chloroflexi (JG37-AG-4), which have previously been detected primarily in peatlands and uranium waste piles. Shotgun metagenomics allowed us to reconstruct 13 high-quality Acidobacteria draft genomes, of which two genomes could be directly linked to dominating groups (DA052, KF-JG30-18) by recovered 16S rRNA gene sequences. Comparative genomics revealed broad carbon utilization capabilities for these two groups of elusive Acidobacteria, including polysaccharide breakdown (cellulose, xylan) and the competence to metabolize C1 compounds (ribulose monophosphate pathway) and lignin derivatives (dye-decolorizing peroxidases). Equipped with a broad range of efflux systems for metal cations and xenobiotics, DA052 and KF-JG30-18 may have a competitive advantage over other bacterial groups in this unique habitat.
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Affiliation(s)
- Carl-Eric Wegner
- Department of Biogeochemistry, Max Planck Institute for Terrestrial MicrobiologyMarburg, Germany
- Aquatic Geomicrobiology, Institute of Ecology, Friedrich Schiller University JenaJena, Germany
| | - Werner Liesack
- Department of Biogeochemistry, Max Planck Institute for Terrestrial MicrobiologyMarburg, Germany
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13
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Yelton AP, Acinas SG, Sunagawa S, Bork P, Pedrós-Alió C, Chisholm SW. Global genetic capacity for mixotrophy in marine picocyanobacteria. THE ISME JOURNAL 2016; 10:2946-2957. [PMID: 27137127 PMCID: PMC5148188 DOI: 10.1038/ismej.2016.64] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 03/02/2016] [Accepted: 03/22/2016] [Indexed: 12/12/2022]
Abstract
The assimilation of organic nutrients by autotrophs, a form of mixotrophy, has been demonstrated in the globally abundant marine picocyanobacterial genera Prochlorococcus and Synechococcus. However, the range of compounds used and the distribution of organic compound uptake genes within picocyanobacteria are unknown. Here we analyze genomic and metagenomic data from around the world to determine the extent and distribution of mixotrophy in these phototrophs. Analysis of 49 Prochlorococcus and 18 Synechococcus isolate genomes reveals that all have the transporters necessary to take up amino acids, peptides and sugars. However, the number and type of transporters and associated catabolic genes differ between different phylogenetic groups, with low-light IV Prochlorococcus, and 5.1B, 5.2 and 5.3 Synechococcus strains having the largest number. Metagenomic data from 68 stations from the Tara Oceans expedition indicate that the genetic potential for mixotrophy in picocyanobacteria is globally distributed and differs between clades. Phylogenetic analyses indicate gradual organic nutrient transporter gene loss from the low-light IV to the high-light II Prochlorococcus. The phylogenetic differences in genetic capacity for mixotrophy, combined with the ubiquity of picocyanobacterial organic compound uptake genes suggests that mixotrophy has a more central role in picocyanobacterial ecology than was previously thought.
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Affiliation(s)
- Alexis P Yelton
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Silvia G Acinas
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar-CMIMA, CSIC, Barcelona, Spain
| | - Shinichi Sunagawa
- European Molecular Biology Laboratory Heidelberg, Heidelberg, Germany
| | - Peer Bork
- European Molecular Biology Laboratory Heidelberg, Heidelberg, Germany
| | - Carlos Pedrós-Alió
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar-CMIMA, CSIC, Barcelona, Spain
| | - Sallie W Chisholm
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
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14
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Zaslavsky L, Ciufo S, Fedorov B, Tatusova T. Clustering analysis of proteins from microbial genomes at multiple levels of resolution. BMC Bioinformatics 2016; 17 Suppl 8:276. [PMID: 27586436 PMCID: PMC5009818 DOI: 10.1186/s12859-016-1112-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Background Microbial genomes at the National Center for Biotechnology Information (NCBI) represent a large collection of more than 35,000 assemblies. There are several complexities associated with the data: a great variation in sampling density since human pathogens are densely sampled while other bacteria are less represented; different protein families occur in annotations with different frequencies; and the quality of genome annotation varies greatly. In order to extract useful information from these sophisticated data, the analysis needs to be performed at multiple levels of phylogenomic resolution and protein similarity, with an adequate sampling strategy. Results Protein clustering is used to construct meaningful and stable groups of similar proteins to be used for analysis and functional annotation. Our approach is to create protein clusters at three levels. First, tight clusters in groups of closely-related genomes (species-level clades) are constructed using a combined approach that takes into account both sequence similarity and genome context. Second, clustroids of conservative in-clade clusters are organized into seed global clusters. Finally, global protein clusters are built around the the seed clusters. We propose filtering strategies that allow limiting the protein set included in global clustering. The in-clade clustering procedure, subsequent selection of clustroids and organization into seed global clusters provides a robust representation and high rate of compression. Seed protein clusters are further extended by adding related proteins. Extended seed clusters include a significant part of the data and represent all major known cell machinery. The remaining part, coming from either non-conservative (unique) or rapidly evolving proteins, from rare genomes, or resulting from low-quality annotation, does not group together well. Processing these proteins requires significant computational resources and results in a large number of questionable clusters. Conclusion The developed filtering strategies allow to identify and exclude such peripheral proteins limiting the protein dataset in global clustering. Overall, the proposed methodology allows the relevant data at different levels of details to be obtained and data redundancy eliminated while keeping biologically interesting variations. Electronic supplementary material The online version of this article (doi:10.1186/s12859-016-1112-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Leonid Zaslavsky
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, 20894, MD, USA.
| | - Stacy Ciufo
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, 20894, MD, USA
| | - Boris Fedorov
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, 20894, MD, USA
| | - Tatiana Tatusova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, 20894, MD, USA
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15
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Lu S, Peiffer S, Lazar CS, Oldham C, Neu TR, Ciobota V, Näb O, Lillicrap A, Rösch P, Popp J, Küsel K. Extremophile microbiomes in acidic and hypersaline river sediments of Western Australia. ENVIRONMENTAL MICROBIOLOGY REPORTS 2016; 8:58-67. [PMID: 26524974 DOI: 10.1111/1758-2229.12351] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 07/30/2015] [Accepted: 10/27/2015] [Indexed: 06/05/2023]
Abstract
We investigated the microbial community compositions in two sediment samples from the acidic (pH ∼3) and hypersaline (>4.5% NaCl) surface waters, which are widespread in Western Australia. In West Dalyup River, large amounts of NaCl, Fe(II) and sulfate are brought by the groundwater into the surface run-off. The presence of K-jarosite and schwertmannite minerals in the river sediments suggested the occurrence of microbial Fe(II) oxidation because chemical oxidation is greatly reduced at low pH. 16S rRNA gene diversity analyses revealed that sequences affiliated with an uncultured archaeal lineage named Aplasma, which has the genomic potential for Fe(II) oxidation, were dominant in both sediment samples. The acidophilic heterotrophs Acidiphilium and Acidocella were identified as the dominant bacterial groups. Acidiphilium strain AusYE3-1 obtained from the river sediment tolerated up to 6% NaCl at pH 3 under oxic conditions and cells of strain AusYE3-1 reduced the effects of high salt content by forming filamentous structure clumping as aggregates. Neither growth nor Fe(III) reduction by strain AusYE3-1 was observed in anoxic salt-containing medium. The detection of Aplasma group as potential Fe(II) oxidizers and the inhibited Fe(III)-reducing capacity of Acidiphilium contributes to our understanding of the microbial ecology of acidic hypersaline environments.
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Affiliation(s)
- Shipeng Lu
- Chair of Aquatic Geomicrobiology, Friedrich Schiller University Jena, Jena, Germany
- The German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Stefan Peiffer
- Department of Hydrology, University of Bayreuth, Bayreuth, Germany
| | - Cassandre Sara Lazar
- The German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Carolyn Oldham
- School of Civil, Environmental and Mining Engineering, The University of Western Australia, Crawley, Australia
| | - Thomas R Neu
- Department of River Ecology, Helmholtz Centre for Environmental Research-UFZ, Magdeburg, Germany
| | - Valerian Ciobota
- Institute of Physical Chemistry and Abbe School of Photonics, Friedrich Schiller University Jena, Jena, Germany
| | - Olga Näb
- Department of Hydrology, University of Bayreuth, Bayreuth, Germany
| | - Adam Lillicrap
- School of Civil, Environmental and Mining Engineering, The University of Western Australia, Crawley, Australia
| | - Petra Rösch
- Institute of Physical Chemistry and Abbe School of Photonics, Friedrich Schiller University Jena, Jena, Germany
| | - Jürgen Popp
- Institute of Physical Chemistry and Abbe School of Photonics, Friedrich Schiller University Jena, Jena, Germany
- Institute of Photonic Technology, Jena, Germany
| | - Kirsten Küsel
- Chair of Aquatic Geomicrobiology, Friedrich Schiller University Jena, Jena, Germany
- The German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
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16
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Ngugi DK, Blom J, Stepanauskas R, Stingl U. Diversification and niche adaptations of Nitrospina-like bacteria in the polyextreme interfaces of Red Sea brines. ISME JOURNAL 2015; 10:1383-99. [PMID: 26657763 PMCID: PMC5029188 DOI: 10.1038/ismej.2015.214] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 10/05/2015] [Accepted: 10/25/2015] [Indexed: 11/22/2022]
Abstract
Nitrite-oxidizing bacteria (NOB) of the genus Nitrospina have exclusively been found in marine environments. In the brine–seawater interface layer of Atlantis II Deep (Red Sea), Nitrospina-like bacteria constitute up to one-third of the bacterial 16S ribosomal RNA (rRNA) gene sequences. This is much higher compared with that reported in other marine habitats (~10% of all bacteria), and was unexpected because no NOB culture has been observed to grow above 4.0% salinity, presumably due to the low net energy gained from their metabolism that is insufficient for both growth and osmoregulation. Using phylogenetics, single-cell genomics and metagenomic fragment recruitment approaches, we document here that these Nitrospina-like bacteria, designated as Candidatus Nitromaritima RS, are not only highly diverged from the type species Nitrospina gracilis (pairwise genome identity of 69%) but are also ubiquitous in the deeper, highly saline interface layers (up to 11.2% salinity) with temperatures of up to 52 °C. Comparative pan-genome analyses revealed that less than half of the predicted proteome of Ca. Nitromaritima RS is shared with N. gracilis. Interestingly, the capacity for nitrite oxidation is also conserved in both genomes. Although both lack acidic proteomes synonymous with extreme halophiles, the pangenome of Ca. Nitromaritima RS specifically encodes enzymes with osmoregulatory and thermoprotective roles (i.e., ectoine/hydroxyectoine biosynthesis) and of thermodynamic importance (i.e., nitrate and nitrite reductases). Ca. Nitromaritima RS also possesses many hallmark traits of microaerophiles and high-affinity NOB. The abundance of the uncultured Ca. Nitromaritima lineage in marine oxyclines suggests their unrecognized ecological significance in deoxygenated areas of the global ocean.
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Affiliation(s)
- David Kamanda Ngugi
- Red Sea Research Centre, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus Liebig University Giessen, Germany
| | | | - Ulrich Stingl
- Red Sea Research Centre, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
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17
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Jun SR, Robeson MS, Hauser LJ, Schadt CW, Gorin AA. PanFP: pangenome-based functional profiles for microbial communities. BMC Res Notes 2015; 8:479. [PMID: 26409790 PMCID: PMC4584126 DOI: 10.1186/s13104-015-1462-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 09/21/2015] [Indexed: 11/30/2022] Open
Abstract
Background For decades there has been increasing interest in understanding the relationships between microbial communities and ecosystem functions. Current DNA sequencing technologies allows for the exploration of microbial communities in two principle ways: targeted rRNA gene surveys and shotgun metagenomics. For large study designs, it is often still prohibitively expensive to sequence metagenomes at both the breadth and depth necessary to statistically capture the true functional diversity of a community. Although rRNA gene surveys provide no direct evidence of function, they do provide a reasonable estimation of microbial diversity, while being a very cost-effective way to screen samples of interest for later shotgun metagenomic analyses. However, there is a great deal of 16S rRNA gene survey data currently available from diverse environments, and thus a need for tools to infer functional composition of environmental samples based on 16S rRNA gene survey data. Results We present a computational method called pangenome-based functional profiles (PanFP), which infers functional profiles of microbial communities from 16S rRNA gene survey data for Bacteria and Archaea. PanFP is based on pangenome reconstruction of a 16S rRNA gene operational taxonomic unit (OTU) from known genes and genomes pooled from the OTU’s taxonomic lineage. From this lineage, we derive an OTU functional profile by weighting a pangenome’s functional profile with the OTUs abundance observed in a given sample. We validated our method by comparing PanFP to the functional profiles obtained from the direct shotgun metagenomic measurement of 65 diverse communities via Spearman correlation coefficients. These correlations improved with increasing sequencing depth, within the range of 0.8–0.9 for the most deeply sequenced Human Microbiome Project mock community samples. PanFP is very similar in performance to another recently released tool, PICRUSt, for almost all of survey data analysed here. But, our method is unique in that any OTU building method can be used, as opposed to being limited to closed-reference OTU picking strategies against specific reference sequence databases. Conclusions We developed an automated computational method, which derives an inferred functional profile based on the 16S rRNA gene surveys of microbial communities. The inferred functional profile provides a cost effective way to study complex ecosystems through predicted comparative functional metagenomes and metadata analysis. All PanFP source code and additional documentation are freely available online at GitHub (https://github.com/srjun/PanFP). Electronic supplementary material The online version of this article (doi:10.1186/s13104-015-1462-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Se-Ran Jun
- Comparative Genomics Group, Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA. .,Joint Institute for Computational Sciences, University of Tennessee, Knoxville, TN, USA.
| | - Michael S Robeson
- Systems Genetics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA. .,Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, CO, USA.
| | - Loren J Hauser
- Comparative Genomics Group, Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
| | - Christopher W Schadt
- Systems Genetics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA. .,Department of Microbiology, University of Tennessee, Knoxville, TN, USA.
| | - Andrey A Gorin
- Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
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18
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Gasc C, Ribière C, Parisot N, Beugnot R, Defois C, Petit-Biderre C, Boucher D, Peyretaillade E, Peyret P. Capturing prokaryotic dark matter genomes. Res Microbiol 2015; 166:814-30. [PMID: 26100932 DOI: 10.1016/j.resmic.2015.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 06/02/2015] [Accepted: 06/03/2015] [Indexed: 11/18/2022]
Abstract
Prokaryotes are the most diverse and abundant cellular life forms on Earth. Most of them, identified by indirect molecular approaches, belong to microbial dark matter. The advent of metagenomic and single-cell genomic approaches has highlighted the metabolic capabilities of numerous members of this dark matter through genome reconstruction. Thus, linking functions back to the species has revolutionized our understanding of how ecosystem function is sustained by the microbial world. This review will present discoveries acquired through the illumination of prokaryotic dark matter genomes by these innovative approaches.
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Affiliation(s)
- Cyrielle Gasc
- Clermont Université, Université d'Auvergne, EA 4678 CIDAM, BP 10448, F-63001 Clermont-Ferrand, France.
| | - Céline Ribière
- Clermont Université, Université d'Auvergne, EA 4678 CIDAM, BP 10448, F-63001 Clermont-Ferrand, France.
| | - Nicolas Parisot
- Biologie Fonctionnelle Insectes et Interactions, UMR203 BF2I, INRA, INSA-Lyon, Université de Lyon, Villeurbanne, France.
| | - Réjane Beugnot
- Clermont Université, Université d'Auvergne, EA 4678 CIDAM, BP 10448, F-63001 Clermont-Ferrand, France.
| | - Clémence Defois
- Clermont Université, Université d'Auvergne, EA 4678 CIDAM, BP 10448, F-63001 Clermont-Ferrand, France.
| | - Corinne Petit-Biderre
- Université Blaise Pascal, Laboratoire Microorganismes, Génome et Environnement, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 6023, F-63171 Aubière, France.
| | - Delphine Boucher
- Clermont Université, Université d'Auvergne, EA 4678 CIDAM, BP 10448, F-63001 Clermont-Ferrand, France.
| | - Eric Peyretaillade
- Clermont Université, Université d'Auvergne, EA 4678 CIDAM, BP 10448, F-63001 Clermont-Ferrand, France.
| | - Pierre Peyret
- Clermont Université, Université d'Auvergne, EA 4678 CIDAM, BP 10448, F-63001 Clermont-Ferrand, France.
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19
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Méndez-García C, Peláez AI, Mesa V, Sánchez J, Golyshina OV, Ferrer M. Microbial diversity and metabolic networks in acid mine drainage habitats. Front Microbiol 2015; 6:475. [PMID: 26074887 PMCID: PMC4448039 DOI: 10.3389/fmicb.2015.00475] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 04/29/2015] [Indexed: 11/13/2022] Open
Abstract
Acid mine drainage (AMD) emplacements are low-complexity natural systems. Low-pH conditions appear to be the main factor underlying the limited diversity of the microbial populations thriving in these environments, although temperature, ionic composition, total organic carbon, and dissolved oxygen are also considered to significantly influence their microbial life. This natural reduction in diversity driven by extreme conditions was reflected in several studies on the microbial populations inhabiting the various micro-environments present in such ecosystems. Early studies based on the physiology of the autochthonous microbiota and the growing success of omics-based methodologies have enabled a better understanding of microbial ecology and function in low-pH mine outflows; however, complementary omics-derived data should be included to completely describe their microbial ecology. Furthermore, recent updates on the distribution of eukaryotes and archaea recovered through sterile filtering (herein referred to as filterable fraction) in these environments demand their inclusion in the microbial characterization of AMD systems. In this review, we present a complete overview of the bacterial, archaeal (including filterable fraction), and eukaryotic diversity in these ecosystems, and include a thorough depiction of the metabolism and element cycling in AMD habitats. We also review different metabolic network structures at the organismal level, which is necessary to disentangle the role of each member of the AMD communities described thus far.
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Affiliation(s)
| | - Ana I. Peláez
- Department of Functional Biology-IUBA, Universidad de OviedoOviedo, Spain
| | - Victoria Mesa
- Department of Functional Biology-IUBA, Universidad de OviedoOviedo, Spain
| | - Jesús Sánchez
- Department of Functional Biology-IUBA, Universidad de OviedoOviedo, Spain
| | | | - Manuel Ferrer
- Department of Applied Biocatalysis, Consejo Superior de Investigaciones Científicas, Institute of CatalysisMadrid, Spain
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20
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Sharon I, Kertesz M, Hug LA, Pushkarev D, Blauwkamp TA, Castelle CJ, Amirebrahimi M, Thomas BC, Burstein D, Tringe SG, Williams KH, Banfield JF. Accurate, multi-kb reads resolve complex populations and detect rare microorganisms. Genome Res 2015; 25:534-43. [PMID: 25665577 PMCID: PMC4381525 DOI: 10.1101/gr.183012.114] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 02/06/2015] [Indexed: 01/18/2023]
Abstract
Accurate evaluation of microbial communities is essential for understanding global biogeochemical processes and can guide bioremediation and medical treatments. Metagenomics is most commonly used to analyze microbial diversity and metabolic potential, but assemblies of the short reads generated by current sequencing platforms may fail to recover heterogeneous strain populations and rare organisms. Here we used short (150-bp) and long (multi-kb) synthetic reads to evaluate strain heterogeneity and study microorganisms at low abundance in complex microbial communities from terrestrial sediments. The long-read data revealed multiple (probably dozens of) closely related species and strains from previously undescribed Deltaproteobacteria and Aminicenantes (candidate phylum OP8). Notably, these are the most abundant organisms in the communities, yet short-read assemblies achieved only partial genome coverage, mostly in the form of short scaffolds (N50 = ∼ 2200 bp). Genome architecture and metabolic potential for these lineages were reconstructed using a new synteny-based method. Analysis of long-read data also revealed thousands of species whose abundances were <0.1% in all samples. Most of the organisms in this "long tail" of rare organisms belong to phyla that are also represented by abundant organisms. Genes encoding glycosyl hydrolases are significantly more abundant than expected in rare genomes, suggesting that rare species may augment the capability for carbon turnover and confer resilience to changing environmental conditions. Overall, the study showed that a diversity of closely related strains and rare organisms account for a major portion of the communities. These are probably common features of many microbial communities and can be effectively studied using a combination of long and short reads.
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Affiliation(s)
- Itai Sharon
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, California 94720, USA
| | - Michael Kertesz
- Department of Bioengineering, Stanford University and Howard Hughes Medical Institute, Stanford University, Stanford, California 94305, USA
| | - Laura A Hug
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, California 94720, USA
| | - Dmitry Pushkarev
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | | | - Cindy J Castelle
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, California 94720, USA
| | - Mojgan Amirebrahimi
- Department of Energy, Joint Genome Institute, Walnut Creek, California 94598, USA
| | - Brian C Thomas
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, California 94720, USA
| | - David Burstein
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, California 94720, USA
| | - Susannah G Tringe
- Department of Energy, Joint Genome Institute, Walnut Creek, California 94598, USA
| | | | - Jillian F Banfield
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, California 94720, USA; Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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21
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Lacroix T, Loux V, Gendrault A, Hoebeke M, Gibrat JF. Insyght: navigating amongst abundant homologues, syntenies and gene functional annotations in bacteria, it's that symbol! Nucleic Acids Res 2014; 42:gku867. [PMID: 25249626 PMCID: PMC4245967 DOI: 10.1093/nar/gku867] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 08/28/2014] [Accepted: 09/10/2014] [Indexed: 11/14/2022] Open
Abstract
High-throughput techniques have considerably increased the potential of comparative genomics whilst simultaneously posing many new challenges. One of those challenges involves efficiently mining the large amount of data produced and exploring the landscape of both conserved and idiosyncratic genomic regions across multiple genomes. Domains of application of these analyses are diverse: identification of evolutionary events, inference of gene functions, detection of niche-specific genes or phylogenetic profiling. Insyght is a comparative genomic visualization tool that combines three complementary displays: (i) a table for thoroughly browsing amongst homologues, (ii) a comparator of orthologue functional annotations and (iii) a genomic organization view designed to improve the legibility of rearrangements and distinctive loci. The latter display combines symbolic and proportional graphical paradigms. Synchronized navigation across multiple species and interoperability between the views are core features of Insyght. A gene filter mechanism is provided that helps the user to build a biologically relevant gene set according to multiple criteria such as presence/absence of homologues and/or various annotations. We illustrate the use of Insyght with scenarios. Currently, only Bacteria and Archaea are supported. A public instance is available at http://genome.jouy.inra.fr/Insyght. The tool is freely downloadable for private data set analysis.
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Affiliation(s)
- Thomas Lacroix
- INRA, UR 1077 Mathématique Informatique et Génome, 78352 Jouy-en-Josas, France
| | - Valentin Loux
- INRA, UR 1077 Mathématique Informatique et Génome, 78352 Jouy-en-Josas, France
| | - Annie Gendrault
- INRA, UR 1077 Mathématique Informatique et Génome, 78352 Jouy-en-Josas, France
| | - Mark Hoebeke
- CNRS, UPMC, FR2424, ABiMS, Station Biologique, 29680 Roscoff, France
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22
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Jimenez-Infante F, Ngugi DK, Alam I, Rashid M, Baalawi W, Kamau AA, Bajic VB, Stingl U. Genomic differentiation among two strains of the PS1 clade isolated from geographically separated marine habitats. FEMS Microbiol Ecol 2014; 89:181-97. [PMID: 24785133 DOI: 10.1111/1574-6941.12348] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 03/20/2014] [Accepted: 04/12/2014] [Indexed: 12/18/2022] Open
Abstract
Using dilution-to-extinction cultivation, we isolated a strain affiliated with the PS1 clade from surface waters of the Red Sea. Strain RS24 represents the second isolate of this group of marine Alphaproteobacteria after IMCC14465 that was isolated from the East (Japan) Sea. The PS1 clade is a sister group to the OCS116 clade, together forming a putatively novel order closely related to Rhizobiales. While most genomic features and most of the genetic content are conserved between RS24 and IMCC14465, their average nucleotide identity (ANI) is < 81%, suggesting two distinct species of the PS1 clade. Next to encoding two different variants of proteorhodopsin genes, they also harbor several unique genomic islands that contain genes related to degradation of aromatic compounds in IMCC14465 and in polymer degradation in RS24, possibly reflecting the physicochemical differences in the environment they were isolated from. No clear differences in abundance of the genomic content of either strain could be found in fragment recruitment analyses using different metagenomic datasets, in which both genomes were detectable albeit as minor part of the communities. The comparative genomic analysis of both isolates of the PS1 clade and the fragment recruitment analysis provide first insights into the ecology of this group.
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Affiliation(s)
- Francy Jimenez-Infante
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
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23
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Thrash JC, Temperton B, Swan BK, Landry ZC, Woyke T, DeLong EF, Stepanauskas R, Giovannoni SJ. Single-cell enabled comparative genomics of a deep ocean SAR11 bathytype. ISME JOURNAL 2014; 8:1440-51. [PMID: 24451205 DOI: 10.1038/ismej.2013.243] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 11/07/2013] [Accepted: 12/10/2013] [Indexed: 11/09/2022]
Abstract
Bacterioplankton of the SAR11 clade are the most abundant microorganisms in marine systems, usually representing 25% or more of the total bacterial cells in seawater worldwide. SAR11 is divided into subclades with distinct spatiotemporal distributions (ecotypes), some of which appear to be specific to deep water. Here we examine the genomic basis for deep ocean distribution of one SAR11 bathytype (depth-specific ecotype), subclade Ic. Four single-cell Ic genomes, with estimated completeness of 55%-86%, were isolated from 770 m at station ALOHA and compared with eight SAR11 surface genomes and metagenomic datasets. Subclade Ic genomes dominated metagenomic fragment recruitment below the euphotic zone. They had similar COG distributions, high local synteny and shared a large number (69%) of orthologous clusters with SAR11 surface genomes, yet were distinct at the 16S rRNA gene and amino-acid level, and formed a separate, monophyletic group in phylogenetic trees. Subclade Ic genomes were enriched in genes associated with membrane/cell wall/envelope biosynthesis and showed evidence of unique phage defenses. The majority of subclade Ic-specfic genes were hypothetical, and some were highly abundant in deep ocean metagenomic data, potentially masking mechanisms for niche differentiation. However, the evidence suggests these organisms have a similar metabolism to their surface counterparts, and that subclade Ic adaptations to the deep ocean do not involve large variations in gene content, but rather more subtle differences previously observed deep ocean genomic data, like preferential amino-acid substitutions, larger coding regions among SAR11 clade orthologs, larger intergenic regions and larger estimated average genome size.
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Affiliation(s)
- J Cameron Thrash
- 1] Department of Microbiology, Oregon State University, Corvallis, OR, USA [2] Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Ben Temperton
- Department of Microbiology, Oregon State University, Corvallis, OR, USA
| | - Brandon K Swan
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, USA
| | - Zachary C Landry
- Department of Microbiology, Oregon State University, Corvallis, OR, USA
| | - Tanja Woyke
- DOE Joint Genome Institute, Walnut Creek, CA, USA
| | - Edward F DeLong
- 1] Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA [2] Center for Microbial Ecology: Research and Education, Honolulu, HI, USA
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Chen YL, Chen CM, Pai TW, Leong HW, Chong KF. Homologous synteny block detection based on suffix tree algorithms. J Bioinform Comput Biol 2014; 11:1343004. [PMID: 24372033 DOI: 10.1142/s021972001343004x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A synteny block represents a set of contiguous genes located within the same chromosome and well conserved among various species. Through long evolutionary processes and genome rearrangement events, large numbers of synteny blocks remain highly conserved across multiple species. Understanding distribution of conserved gene blocks facilitates evolutionary biologists to trace the diversity of life, and it also plays an important role for orthologous gene detection and gene annotation in the genomic era. In this work, we focus on collinear synteny detection in which the order of genes is required and well conserved among multiple species. To achieve this goal, the suffix tree based algorithms for efficiently identifying homologous synteny blocks was proposed. The traditional suffix tree algorithm was modified by considering a chromosome as a string and each gene in a chromosome is encoded as a symbol character. Hence, a suffix tree can be built for different query chromosomes from various species. We can then efficiently search for conserved synteny blocks that are modeled as overlapped contiguous edges in our suffix tree. In addition, we defined a novel Synteny Block Conserved Index (SBCI) to evaluate the relationship of synteny block distribution between two species, and which could be applied as an evolutionary indicator for constructing a phylogenetic tree from multiple species instead of performing large computational requirements through whole genome sequence alignment.
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Affiliation(s)
- Yu-Lun Chen
- Department of Computer Science and Engineering and Center of Excellence for the Oceans, National Taiwan Ocean University, No. 2 Peining Road, Keelung, Taiwan 20224, Republic of China
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25
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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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Comparative and phylogenomic evidence that the alphaproteobacterium HIMB59 is not a member of the oceanic SAR11 clade. PLoS One 2013; 8:e78858. [PMID: 24223857 PMCID: PMC3815206 DOI: 10.1371/journal.pone.0078858] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 09/05/2013] [Indexed: 11/19/2022] Open
Abstract
SAR11 is a globally abundant group of Alphaproteobacteria in the oceans that is taxonomically not well defined. It has been suggested SAR11 should be classified into the novel order Pelagibacterales. Features such as conservation of gene content and synteny have been taken as evidence that also the divergent member HIMB59 should be included in the order. However, this proposition is controversial since phylogenetic analyses have questioned the monophyly of this grouping. Here, we performed phylogenetic analyses and reinvestigated the genomic similarity of SAR11 and HIMB59. Our phylogenetic analysis confirmed that HIMB59 is not a sister group to the other SAR11 strains. By placing the comparison in the context of the evolution of the Alphaproteobacteria, we found that none of the measures of genomic similarity supports a clustering of HIMB59 and SAR11 to the exclusion of other Alphaproteobacteria. First, pairwise sequence similarity measures for the SAR11 and HIMB59 genomes were within the range observed for unrelated pairs of Alphaproteobacteria. Second, pairwise comparisons of gene contents revealed a higher similarity of SAR11 to several other alphaproteobacterial genomes than to HIMB59. Third, the SAR11 genomes are not more similar in gene order to the HIMB59 genome than what they are to several other alphaproteobacterial genomes. Finally, in contrast to earlier reports, we observed no sequence similarity between the hypervariable region HVR2 in the SAR11 genomes and the region located at the corresponding position in the HIMB59 genome. Based on these observations, we conclude that the alphaproteobacterium HIMB59 is not monophyletic with the SAR11 strains and that genome streamlining has evolved multiple times independently in Alphaproteobacteria adapted to the upper surface waters of the oceans.
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27
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Yelton AP, Comolli LR, Justice NB, Castelle C, Denef VJ, Thomas BC, Banfield JF. Comparative genomics in acid mine drainage biofilm communities reveals metabolic and structural differentiation of co-occurring archaea. BMC Genomics 2013; 14:485. [PMID: 23865623 PMCID: PMC3750248 DOI: 10.1186/1471-2164-14-485] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 07/15/2013] [Indexed: 11/10/2022] Open
Abstract
Background Metal sulfide mineral dissolution during bioleaching and acid mine drainage (AMD) formation creates an environment that is inhospitable to most life. Despite dominance by a small number of bacteria, AMD microbial biofilm communities contain a notable variety of coexisting and closely related Euryarchaea, most of which have defied cultivation efforts. For this reason, we used metagenomics to analyze variation in gene content that may contribute to niche differentiation among co-occurring AMD archaea. Our analyses targeted members of the Thermoplasmatales and related archaea. These results greatly expand genomic information available for this archaeal order. Results We reconstructed near-complete genomes for uncultivated, relatively low abundance organisms A-, E-, and Gplasma, members of Thermoplasmatales order, and for a novel organism, Iplasma. Genomic analyses of these organisms, as well as Ferroplasma type I and II, reveal that all are facultative aerobic heterotrophs with the ability to use many of the same carbon substrates, including methanol. Most of the genomes share genes for toxic metal resistance and surface-layer production. Only Aplasma and Eplasma have a full suite of flagellar genes whereas all but the Ferroplasma spp. have genes for pili production. Cryogenic-electron microscopy (cryo-EM) and tomography (cryo-ET) strengthen these metagenomics-based ultrastructural predictions. Notably, only Aplasma, Gplasma and the Ferroplasma spp. have predicted iron oxidation genes and Eplasma and Iplasma lack most genes for cobalamin, valine, (iso)leucine and histidine synthesis. Conclusion The Thermoplasmatales AMD archaea share a large number of metabolic capabilities. All of the uncultivated organisms studied here (A-, E-, G-, and Iplasma) are metabolically very similar to characterized Ferroplasma spp., differentiating themselves mainly in their genetic capabilities for biosynthesis, motility, and possibly iron oxidation. These results indicate that subtle, but important genomic differences, coupled with unknown differences in gene expression, distinguish these organisms enough to allow for co-existence. Overall this study reveals shared features of organisms from the Thermoplasmatales lineage and provides new insights into the functioning of AMD communities.
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Affiliation(s)
- Alexis P Yelton
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, USA
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28
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Chen Y, Yang L, Ding Y, Zhang S, He T, Mao F, Zhang C, Zhang H, Huo C, Liu P. Tracing evolutionary footprints to identify novel gene functional linkages. PLoS One 2013; 8:e66817. [PMID: 23825567 PMCID: PMC3692504 DOI: 10.1371/journal.pone.0066817] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 05/13/2013] [Indexed: 11/19/2022] Open
Abstract
Systematic determination of gene function is an essential step in fully understanding the precise contribution of each gene for the proper execution of molecular functions in the cell. Gene functional linkage is defined as to describe the relationship of a group of genes with similar functions. With thousands of genomes sequenced, there arises a great opportunity to utilize gene evolutionary information to identify gene functional linkages. To this end, we established a computational method (called TRACE) to trace gene footprints through a gene functional network constructed from 341 prokaryotic genomes. TRACE performance was validated and successfully tested to predict enzyme functions as well as components of pathway. A so far undescribed chromosome partitioning-like protein ro03654 of an oleaginous bacteria Rhodococcus sp. RHA1 (RHA1) was predicted and verified experimentally with its deletion mutant showing growth inhibition compared to RHA1 wild type. In addition, four proteins were predicted to act as prokaryotic SNARE-like proteins, and two of them were shown to be localized at the plasma membrane. Thus, we believe that TRACE is an effective new method to infer prokaryotic gene functional linkages by tracing evolutionary events.
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Affiliation(s)
- Yong Chen
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- * E-mail: (PL); (YC)
| | - Li Yang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yunfeng Ding
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Shuyan Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Tong He
- School of Applied Mathematics, Central University of Finance and Economics, Beijing, China
| | - Fenglou Mao
- Computational Systems Biology Laboratory, Department of Biochemistry and Molecular Biology, Institute of Bioinformatics, University of Georgia, Athens, Georgia, United States of America
| | - Congyan Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Huina Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Chaoxing Huo
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Pingsheng Liu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- * E-mail: (PL); (YC)
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29
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Handley KM, VerBerkmoes NC, Steefel CI, Williams KH, Sharon I, Miller CS, Frischkorn KR, Chourey K, Thomas BC, Shah MB, Long PE, Hettich RL, Banfield JF. Biostimulation induces syntrophic interactions that impact C, S and N cycling in a sediment microbial community. THE ISME JOURNAL 2013; 7:800-16. [PMID: 23190730 PMCID: PMC3603403 DOI: 10.1038/ismej.2012.148] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 09/28/2012] [Accepted: 10/08/2012] [Indexed: 11/09/2022]
Abstract
Stimulation of subsurface microorganisms to induce reductive immobilization of metals is a promising approach for bioremediation, yet the overall microbial community response is typically poorly understood. Here we used proteogenomics to test the hypothesis that excess input of acetate activates complex community functioning and syntrophic interactions among autotrophs and heterotrophs. A flow-through sediment column was incubated in a groundwater well of an acetate-amended aquifer and recovered during microbial sulfate reduction. De novo reconstruction of community sequences yielded near-complete genomes of Desulfobacter (Deltaproteobacteria), Sulfurovum- and Sulfurimonas-like Epsilonproteobacteria and Bacteroidetes. Partial genomes were obtained for Clostridiales (Firmicutes) and Desulfuromonadales-like Deltaproteobacteria. The majority of proteins identified by mass spectrometry corresponded to Desulfobacter-like species, and demonstrate the role of this organism in sulfate reduction (Dsr and APS), nitrogen fixation and acetate oxidation to CO2 during amendment. Results indicate less abundant Desulfuromonadales, and possibly Bacteroidetes, also actively contributed to CO2 production via the tricarboxylic acid (TCA) cycle. Proteomic data indicate that sulfide was partially re-oxidized by Epsilonproteobacteria through nitrate-dependent sulfide oxidation (using Nap, Nir, Nos, SQR and Sox), with CO2 fixed using the reverse TCA cycle. We infer that high acetate concentrations, aimed at stimulating anaerobic heterotrophy, led to the co-enrichment of, and carbon fixation in Epsilonproteobacteria. Results give an insight into ecosystem behavior following addition of simple organic carbon to the subsurface, and demonstrate a range of biological processes and community interactions were stimulated.
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Affiliation(s)
- Kim M Handley
- Department of Earth and Planetary Science,
University of California, Berkeley, CA,
USA
| | - Nathan C VerBerkmoes
- Chemical Sciences and Biosciences Divisions,
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN,
USA
| | - Carl I Steefel
- Earth Science Division, Lawrence Berkeley
National Laboratory (LBNL), Berkeley, CA,
USA
| | - Kenneth H Williams
- Earth Science Division, Lawrence Berkeley
National Laboratory (LBNL), Berkeley, CA,
USA
| | - Itai Sharon
- Department of Earth and Planetary Science,
University of California, Berkeley, CA,
USA
| | - Christopher S Miller
- Department of Earth and Planetary Science,
University of California, Berkeley, CA,
USA
| | - Kyle R Frischkorn
- Department of Earth and Planetary Science,
University of California, Berkeley, CA,
USA
| | - Karuna Chourey
- Chemical Sciences and Biosciences Divisions,
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN,
USA
| | - Brian C Thomas
- Department of Earth and Planetary Science,
University of California, Berkeley, CA,
USA
| | - Manesh B Shah
- Chemical Sciences and Biosciences Divisions,
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN,
USA
| | - Philip E Long
- Earth Science Division, Lawrence Berkeley
National Laboratory (LBNL), Berkeley, CA,
USA
| | - Robert L Hettich
- Chemical Sciences and Biosciences Divisions,
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN,
USA
| | - Jillian F Banfield
- Department of Earth and Planetary Science,
University of California, Berkeley, CA,
USA
- Earth Science Division, Lawrence Berkeley
National Laboratory (LBNL), Berkeley, CA,
USA
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30
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Justice NB, Pan C, Mueller R, Spaulding SE, Shah V, Sun CL, Yelton AP, Miller CS, Thomas BC, Shah M, VerBerkmoes N, Hettich R, Banfield JF. Heterotrophic archaea contribute to carbon cycling in low-pH, suboxic biofilm communities. Appl Environ Microbiol 2012; 78:8321-30. [PMID: 23001646 PMCID: PMC3497393 DOI: 10.1128/aem.01938-12] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 09/13/2012] [Indexed: 11/20/2022] Open
Abstract
Archaea are widely distributed and yet are most often not the most abundant members of microbial communities. Here, we document a transition from Bacteria- to Archaea-dominated communities in microbial biofilms sampled from the Richmond Mine acid mine drainage (AMD) system (∼pH 1.0, ∼38°C) and in laboratory-cultivated biofilms. This transition occurs when chemoautotrophic microbial communities that develop at the air-solution interface sink to the sediment-solution interface and degrade under microaerobic and anaerobic conditions. The archaea identified in these sunken biofilms are from the class Thermoplasmata, and in some cases, the highly divergent ARMAN nanoarchaeal lineage. In several of the sunken biofilms, nanoarchaea comprise 10 to 25% of the community, based on fluorescent in situ hybridization and metagenomic analyses. Comparative community proteomic analyses show a persistence of bacterial proteins in sunken biofilms, but there is clear evidence for amino acid modifications due to acid hydrolysis. Given the low representation of bacterial cells in sunken biofilms based on microscopy, we infer that hydrolysis reflects proteins derived from lysed cells. For archaea, we detected ∼2,400 distinct proteins, including a subset involved in proteolysis and peptide uptake. Laboratory cultivation experiments using complex carbon substrates demonstrated anaerobic enrichment of Ferroplasma and Aplasma coupled to the reduction of ferric iron. These findings indicate dominance of acidophilic archaea in degrading biofilms and suggest that they play roles in anaerobic nutrient cycling at low pH.
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Affiliation(s)
| | - Chongle Pan
- Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Ryan Mueller
- University of California–Berkeley, Berkeley, California, USA
| | | | - Vega Shah
- University of California–Berkeley, Berkeley, California, USA
| | | | | | | | - Brian C. Thomas
- University of California–Berkeley, Berkeley, California, USA
| | - Manesh Shah
- Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | | | - Robert Hettich
- Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
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Abstract
SAR11 is an ancient and diverse clade of heterotrophic bacteria that are abundant throughout the world’s oceans, where they play a major role in the ocean carbon cycle. Correlations between the phylogenetic branching order and spatiotemporal patterns in cell distributions from planktonic ocean environments indicate that SAR11 has evolved into perhaps a dozen or more specialized ecotypes that span evolutionary distances equivalent to a bacterial order. We isolated and sequenced genomes from diverse SAR11 cultures that represent three major lineages and encompass the full breadth of the clade. The new data expand observations about genome evolution and gene content that previously had been restricted to the SAR11 Ia subclade, providing a much broader perspective on the clade’s origins, evolution, and ecology. We found small genomes throughout the clade and a very high proportion of core genome genes (48 to 56%), indicating that small genome size is probably an ancestral characteristic. In their level of core genome conservation, the members of SAR11 are outliers, the most conserved free-living bacteria known. Shared features of the clade include low GC content, high gene synteny, a large hypervariable region bounded by rRNA genes, and low numbers of paralogs. Variation among the genomes included genes for phosphorus metabolism, glycolysis, and C1 metabolism, suggesting that adaptive specialization in nutrient resource utilization is important to niche partitioning and ecotype divergence within the clade. These data provide support for the conclusion that streamlining selection for efficient cell replication in the planktonic habitat has occurred throughout the evolution and diversification of this clade. The SAR11 clade is the most abundant group of marine microorganisms worldwide, making them key players in the global carbon cycle. Growing knowledge about their biochemistry and metabolism is leading to a more mechanistic understanding of organic carbon oxidation and sequestration in the oceans. The discovery of small genomes in SAR11 provided crucial support for the theory that streamlining selection can drive genome reduction in low-nutrient environments. Study of isolates in culture revealed atypical organic nutrient requirements that can be attributed to genome reduction, such as conditional auxotrophy for glycine and its precursors, a requirement for reduced sulfur compounds, and evidence for widespread cycling of C1 compounds in marine environments. However, understanding the genetic variation and distribution of such pathways and characteristics like streamlining throughout the group has required the isolation and genome sequencing of diverse SAR11 representatives, an analysis of which we provide here.
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32
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Weinberger AD, Sun CL, Pluciński MM, Denef VJ, Thomas BC, Horvath P, Barrangou R, Gilmore MS, Getz WM, Banfield JF. Persisting viral sequences shape microbial CRISPR-based immunity. PLoS Comput Biol 2012; 8:e1002475. [PMID: 22532794 PMCID: PMC3330103 DOI: 10.1371/journal.pcbi.1002475] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 02/29/2012] [Indexed: 12/26/2022] Open
Abstract
Well-studied innate immune systems exist throughout bacteria and archaea, but a more recently discovered genomic locus may offer prokaryotes surprising immunological adaptability. Mediated by a cassette-like genomic locus termed Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR), the microbial adaptive immune system differs from its eukaryotic immune analogues by incorporating new immunities unidirectionally. CRISPR thus stores genomically recoverable timelines of virus-host coevolution in natural organisms refractory to laboratory cultivation. Here we combined a population genetic mathematical model of CRISPR-virus coevolution with six years of metagenomic sequencing to link the recoverable genomic dynamics of CRISPR loci to the unknown population dynamics of virus and host in natural communities. Metagenomic reconstructions in an acid-mine drainage system document CRISPR loci conserving ancestral immune elements to the base-pair across thousands of microbial generations. This 'trailer-end conservation' occurs despite rapid viral mutation and despite rapid prokaryotic genomic deletion. The trailer-ends of many reconstructed CRISPR loci are also largely identical across a population. 'Trailer-end clonality' occurs despite predictions of host immunological diversity due to negative frequency dependent selection (kill the winner dynamics). Statistical clustering and model simulations explain this lack of diversity by capturing rapid selective sweeps by highly immune CRISPR lineages. Potentially explaining 'trailer-end conservation,' we record the first example of a viral bloom overwhelming a CRISPR system. The polyclonal viruses bloom even though they share sequences previously targeted by host CRISPR loci. Simulations show how increasing random genomic deletions in CRISPR loci purges immunological controls on long-lived viral sequences, allowing polyclonal viruses to bloom and depressing host fitness. Our results thus link documented patterns of genomic conservation in CRISPR loci to an evolutionary advantage against persistent viruses. By maintaining old immunities, selection may be tuning CRISPR-mediated immunity against viruses reemerging from lysogeny or migration.
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Affiliation(s)
- Ariel D. Weinberger
- Biophysics Graduate Group, University of California, Berkeley, California, United States of America
- Departments of Ophthalmology and Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Christine L. Sun
- Department of Plant and Microbial Biology, University of California, Berkeley, California, United States of America
| | - Mateusz M. Pluciński
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California, United States of America
- Division of Epidemiology, School of Public Health, University of California, Berkeley, California, United States of America
| | - Vincent J. Denef
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California, United States of America
| | - Brian C. Thomas
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California, United States of America
| | | | - Rodolphe Barrangou
- DuPont Nutrition and Health, Madison, Wisconsin, United States of America
| | - Michael S. Gilmore
- Departments of Ophthalmology and Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Microbial Sciences Initiative, Harvard University, Cambridge, Massachusetts, United States of America
| | - Wayne M. Getz
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California, United States of America
| | - Jillian F. Banfield
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California, United States of America
- Department of Earth and Planetary Sciences, University of California, Berkeley, California, United States of America
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