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Babar TK, Glare TR, Hampton JG, Hurst MRH, Narciso J. Biochemical characterisation and production kinetics of high molecular-weight (HMW) putative antibacterial proteins of insect pathogenic Brevibacillus laterosporus isolates. BMC Microbiol 2024; 24:259. [PMID: 38997685 PMCID: PMC11245835 DOI: 10.1186/s12866-024-03340-2] [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: 08/15/2023] [Accepted: 05/16/2024] [Indexed: 07/14/2024] Open
Abstract
BACKGROUND Bacterial genomes often encode structures similar to phage capsids (encapsulins) and phage tails which can be induced spontaneously or using genotoxic compounds such as mitomycin C. These high molecular-weight (HMW) putative antibacterial proteins (ABPs) are used against the competitive strains under natural environment. Previously, it was unknown whether these HMW putative ABPs originating from the insect pathogenic Gram-positive, spore-forming bacterium Brevibacillus laterosporus (Bl) isolates (1821L, 1951) are spontaneously induced during the growth and pose a detrimental effect on their own survival. Furthermore, no prior work has been undertaken to determine their biochemical characteristics. RESULTS Using a soft agar overlay method with polyethylene glycol precipitation, a narrow spectrum of bioactivity was found from the precipitated lysate of Bl 1951. Electron micrographs of mitomycin C- induced filtrates showed structures similar to phage capsids and contractile tails. Bioactivity assays of cell free supernatants (CFS) extracted during the growth of Bl 1821L and Bl 1951 suggested spontaneous induction of these HMW putative ABPs with an autocidal activity. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of spontaneously induced putative ABPs showed appearance of ~ 30 kDa and ~ 48 kDa bands of varying intensity across all the time intervals during the bacterial growth except in the initial hours. Statistically, spontaneously induced HMW putative ABPs of Bl 1951 exhibited a significant decrease in the number of viable cells of its producer strain after 18 h of growth in liquid. In addition, a significant change in pH and prominent bioactivity of the CFS of this particular time period was noted. Biochemically, the filtered supernatant derived from either Bl 1821L or Bl 1951 maintained bioactivity over a wide range of pH and temperature. CONCLUSION This study reports the spontaneous induction of HMW putative ABPs (bacteriocins) of Bl 1821L and Bl 1951 isolates during the course of growth with potential autocidal activity which is critically important during production as a potential biopesticide. A narrow spectrum of putative antibacterial activity of Bl 1951 precipitate was found. The stability of HMW putative ABPs of Bl 1821L and Bl 1951 over a wide range of pH and temperature can be useful in expanding the potential of this useful bacterium beyond the insecticidal value.
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Affiliation(s)
- Tauseef K Babar
- Bioprotection Research Centre, Lincoln University, Lincoln, Canterbury, 7647, New Zealand.
- Department of Entomology, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan, 60000, Pakistan.
| | - Travis R Glare
- Bioprotection Research Centre, Lincoln University, Lincoln, Canterbury, 7647, New Zealand
- Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln, Canterbury, 7647, New Zealand
| | - John G Hampton
- Bioprotection Research Centre, Lincoln University, Lincoln, Canterbury, 7647, New Zealand
- Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln, Canterbury, 7647, New Zealand
| | - Mark R H Hurst
- Resilient agriculture, AgResearch, Lincoln Research Centre, Christchurch, New Zealand
| | - Josefina Narciso
- Bioprotection Research Centre, Lincoln University, Lincoln, Canterbury, 7647, New Zealand
- Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln, Canterbury, 7647, New Zealand
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2
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Hanke DM, Wang Y, Dagan T. Pseudogenes in plasmid genomes reveal past transitions in plasmid mobility. Nucleic Acids Res 2024; 52:7049-7062. [PMID: 38808675 PMCID: PMC11229322 DOI: 10.1093/nar/gkae430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 04/23/2024] [Accepted: 05/08/2024] [Indexed: 05/30/2024] Open
Abstract
Evidence for gene non-functionalization due to mutational processes is found in genomes in the form of pseudogenes. Pseudogenes are known to be rare in prokaryote chromosomes, with the exception of lineages that underwent an extreme genome reduction (e.g. obligatory symbionts). Much less is known about the frequency of pseudogenes in prokaryotic plasmids; those are genetic elements that can transfer between cells and may encode beneficial traits for their host. Non-functionalization of plasmid-encoded genes may alter the plasmid characteristics, e.g. mobility, or their effect on the host. Analyzing 10 832 prokaryotic genomes, we find that plasmid genomes are characterized by threefold-higher pseudogene density compared to chromosomes. The majority of plasmid pseudogenes correspond to deteriorated transposable elements. A detailed analysis of enterobacterial plasmids furthermore reveals frequent gene non-functionalization events associated with the loss of plasmid self-transmissibility. Reconstructing the evolution of closely related plasmids reveals that non-functionalization of the conjugation machinery led to the emergence of non-mobilizable plasmid types. Examples are virulence plasmids in Escherichia and Salmonella. Our study highlights non-functionalization of core plasmid mobility functions as one route for the evolution of domesticated plasmids. Pseudogenes in plasmids supply insights into past transitions in plasmid mobility that are akin to transitions in bacterial lifestyle.
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Affiliation(s)
- Dustin M Hanke
- Institute of General Microbiology, Kiel University, Kiel, Germany
| | - Yiqing Wang
- Institute of General Microbiology, Kiel University, Kiel, Germany
| | - Tal Dagan
- Institute of General Microbiology, Kiel University, Kiel, Germany
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3
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Yang Y, Wang P, Qaidi SE, Hardwidge PR, Huang J, Zhu G. Loss to gain: pseudogenes in microorganisms, focusing on eubacteria, and their biological significance. Appl Microbiol Biotechnol 2024; 108:328. [PMID: 38717672 PMCID: PMC11078800 DOI: 10.1007/s00253-023-12971-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/26/2023] [Accepted: 12/01/2023] [Indexed: 05/12/2024]
Abstract
Pseudogenes are defined as "non-functional" copies of corresponding parent genes. The cognition of pseudogenes continues to be refreshed through accumulating and updating research findings. Previous studies have predominantly focused on mammals, but pseudogenes have received relatively less attention in the field of microbiology. Given the increasing recognition on the importance of pseudogenes, in this review, we focus on several aspects of microorganism pseudogenes, including their classification and characteristics, their generation and fate, their identification, their abundance and distribution, their impact on virulence, their ability to recombine with functional genes, the extent to which some pseudogenes are transcribed and translated, and the relationship between pseudogenes and viruses. By summarizing and organizing the latest research progress, this review will provide a comprehensive perspective and improved understanding on pseudogenes in microorganisms. KEY POINTS: • Concept, classification and characteristics, identification and databases, content, and distribution of microbial pseudogenes are presented. • How pseudogenization contribute to pathogen virulence is highlighted. • Pseudogenes with potential functions in microorganisms are discussed.
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Affiliation(s)
- Yi Yang
- College of Veterinary Medicine, Yangzhou University, 12 East Wenhui Road, Yangzhou, 225009, Jiangsu, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China
- Joint Laboratory of International Cooperation On Prevention and Control Technology of Important Animal Diseases and Zoonoses of Jiangsu Higher Education Institutions, Yangzhou, 225009, China
| | - Pengzhi Wang
- College of Veterinary Medicine, Yangzhou University, 12 East Wenhui Road, Yangzhou, 225009, Jiangsu, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China
- Joint Laboratory of International Cooperation On Prevention and Control Technology of Important Animal Diseases and Zoonoses of Jiangsu Higher Education Institutions, Yangzhou, 225009, China
| | - Samir El Qaidi
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
| | - Philip R Hardwidge
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
| | - Jinlin Huang
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China.
- Jiangsu Key Lab of Zoonosis, Yangzhou University, Yangzhou, 225009, Jiangsu, China.
- College of Bioscience and Biotechnology, Yangzhou University, 12 East Wenhui Road Yangzhou, Jiangsu, 225009, China.
| | - Guoqiang Zhu
- College of Veterinary Medicine, Yangzhou University, 12 East Wenhui Road, Yangzhou, 225009, Jiangsu, China.
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China.
- Joint Laboratory of International Cooperation On Prevention and Control Technology of Important Animal Diseases and Zoonoses of Jiangsu Higher Education Institutions, Yangzhou, 225009, China.
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4
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Gucwa K, Wons E, Wisniewska A, Jakalski M, Dubiak Z, Kozlowski LP, Mruk I. Lethal perturbation of an Escherichia coli regulatory network is triggered by a restriction-modification system's regulator and can be mitigated by excision of the cryptic prophage Rac. Nucleic Acids Res 2024; 52:2942-2960. [PMID: 38153127 PMCID: PMC11014345 DOI: 10.1093/nar/gkad1234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 12/08/2023] [Accepted: 12/13/2023] [Indexed: 12/29/2023] Open
Abstract
Bacterial gene regulatory networks orchestrate responses to environmental challenges. Horizontal gene transfer can bring in genes with regulatory potential, such as new transcription factors (TFs), and this can disrupt existing networks. Serious regulatory perturbations may even result in cell death. Here, we show the impact on Escherichia coli of importing a promiscuous TF that has adventitious transcriptional effects within the cryptic Rac prophage. A cascade of regulatory network perturbations occurred on a global level. The TF, a C regulatory protein, normally controls a Type II restriction-modification system, but in E. coli K-12 interferes with expression of the RacR repressor gene, resulting in de-repression of the normally-silent Rac ydaT gene. YdaT is a prophage-encoded TF with pleiotropic effects on E. coli physiology. In turn, YdaT alters expression of a variety of bacterial regulons normally controlled by the RcsA TF, resulting in deficient lipopolysaccharide biosynthesis and cell division. At the same time, insufficient RacR repressor results in Rac DNA excision, halting Rac gene expression due to loss of the replication-defective Rac prophage. Overall, Rac induction appears to counteract the lethal toxicity of YdaT. We show here that E. coli rewires its regulatory network, so as to minimize the adverse regulatory effects of the imported C TF. This complex set of interactions may reflect the ability of bacteria to protect themselves by having robust mechanisms to maintain their regulatory networks, and/or suggest that regulatory C proteins from mobile operons are under selection to manipulate their host's regulatory networks for their own benefit.
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Affiliation(s)
- Katarzyna Gucwa
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
| | - Ewa Wons
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
| | - Aleksandra Wisniewska
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
| | - Marcin Jakalski
- 3P-Medicine Laboratory, Medical University of Gdansk, Debinki 7, 80-211 Gdansk, Poland
| | - Zuzanna Dubiak
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
| | - Lukasz Pawel Kozlowski
- Institute of Informatics, Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland
| | - Iwona Mruk
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
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Sudhakari PA, Ramisetty BCM. An Eco-evolutionary Model on Surviving Lysogeny Through Grounding and Accumulation of Prophages. MICROBIAL ECOLOGY 2023; 86:3068-3081. [PMID: 37843655 DOI: 10.1007/s00248-023-02301-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 09/14/2023] [Indexed: 10/17/2023]
Abstract
Temperate phages integrate into the bacterial genomes propagating along with the bacterial genomes. Multiple phage elements, representing diverse prophages, are present in most bacterial genomes. The evolutionary events and the ecological dynamics underlying the accumulation of prophage elements in bacterial genomes have yet to be understood. Here, we show that the local wastewater had 7% of lysogens (hosting mitomycin C-inducible prophages), and they showed resistance to superinfection by their corresponding lysates. Genomic analysis of four lysogens and four non-lysogens revealed the presence of multiple prophages (belonging to Myoviridae and Siphoviridae) in both lysogens and non-lysogens. For large-scale comparison, 2180 Escherichia coli genomes isolated from various sources across the globe and 523 genomes specifically isolated from diverse wastewaters were analyzed. A total of 15,279 prophages were predicted among 2180 E. coli genomes and 2802 prophages among 523 global wastewater isolates, with a mean of ~ 5 prophages per genome. These observations indicate that most putative prophages are relics of past bacteria-phage conflicts; they are "grounded" prophages that cannot excise from the bacterial genome. Prophage distribution analysis based on the sequence homology suggested the random distribution of E. coli prophages within and between E. coli clades. The independent occurrence pattern of these prophages indicates extensive horizontal transfers across the genomes. We modeled the eco-evolutionary dynamics to reconstruct the events that could have resulted in the prophage accumulation accounting for infection, superinfection immunity, and grounding. In bacteria-phage conflicts, the bacteria win by grounding the prophage, which could confer superinfection immunity.
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Affiliation(s)
- Pavithra Anantharaman Sudhakari
- Laboratory of Molecular Biology and Evolution, School of Chemical and Biotechnology, SASTRA Deemed University, 312@ASK1, Thanjavur, India
| | - Bhaskar Chandra Mohan Ramisetty
- Laboratory of Molecular Biology and Evolution, School of Chemical and Biotechnology, SASTRA Deemed University, 312@ASK1, Thanjavur, India.
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6
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Liu P, Li Y, Ye Y, Chen J, Li R, Zhang Q, Li Y, Wang W, Meng Q, Ou J, Yang Z, Sun W, Gu W. The genome and antigen proteome analysis of Spiroplasma mirum. Front Microbiol 2022; 13:996938. [PMID: 36406404 PMCID: PMC9666726 DOI: 10.3389/fmicb.2022.996938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023] Open
Abstract
Spiroplasma mirum, small motile wall-less bacteria, was originally isolated from a rabbit tick and had the ability to infect newborn mice and caused cataracts. In this study, the whole genome and antigen proteins of S. mirum were comparative analyzed and investigated. Glycolysis, pentose phosphate pathway, arginine metabolism, nucleotide biosynthesis, and citrate fermentation were found in S. mirum, while trichloroacetic acid, fatty acids metabolism, phospholipid biosynthesis, terpenoid biosynthesis, lactose-specific PTS, and cofactors synthesis were completely absent. The Sec systems of S. mirum consist of SecA, SecE, SecDF, SecG, SecY, and YidC. Signal peptidase II was identified in S. mirum, but no signal peptidase I. The relative gene order in S. mirum is largely conserved. Genome analysis of available species in Mollicutes revealed that they shared only 84 proteins. S. mirum genome has 381 pseudogenes, accounting for 31.6% of total protein-coding genes. This is the evidence that spiroplasma genome is under an ongoing genome reduction. Immunoproteomics, a new scientific technique combining proteomics and immunological analytical methods, provided the direction of our research on S. mirum. We identified 49 proteins and 11 proteins (9 proteins in common) in S. mirum by anti-S. mirum serum and negative serum, respectively. Forty proteins in S. mirum were identified in relation to the virulence. All these proteins may play key roles in the pathogeny and can be used in the future for diagnoses and prevention.
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Affiliation(s)
- Peng Liu
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Yuxin Li
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Youyuan Ye
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Jiaxin Chen
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Rong Li
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Qinyi Zhang
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Yuan Li
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Wen Wang
- Key Laboratory for Aquatic Crustacean Diseases, College of Marine Science and Engineering, Nanjing Normal University, Nanjing, China
| | - Qingguo Meng
- Key Laboratory for Aquatic Crustacean Diseases, College of Marine Science and Engineering, Nanjing Normal University, Nanjing, China
| | - Jingyu Ou
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Zhujun Yang
- Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Basic Medical School, Hengyang Medical School, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Wei Sun
- Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, China
| | - Wei Gu
- Key Laboratory for Aquatic Crustacean Diseases, College of Marine Science and Engineering, Nanjing Normal University, Nanjing, China
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7
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Martinez-Gutierrez CA, Aylward FO. Genome size distributions in bacteria and archaea are strongly linked to evolutionary history at broad phylogenetic scales. PLoS Genet 2022; 18:e1010220. [PMID: 35605022 PMCID: PMC9166353 DOI: 10.1371/journal.pgen.1010220] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 06/03/2022] [Accepted: 04/26/2022] [Indexed: 12/30/2022] Open
Abstract
The evolutionary forces that determine genome size in bacteria and archaea have been the subject of intense debate over the last few decades. Although the preferential loss of genes observed in prokaryotes is explained through the deletional bias, factors promoting and preventing the fixation of such gene losses often remain unclear. Importantly, statistical analyses on this topic typically do not consider the potential bias introduced by the shared ancestry of many lineages, which is critical when using species as data points because of the potential dependence on residuals. In this study, we investigated the genome size distributions across a broad diversity of bacteria and archaea to evaluate if this trait is phylogenetically conserved at broad phylogenetic scales. After model fit, Pagel’s lambda indicated a strong phylogenetic signal in genome size data, suggesting that the diversification of this trait is influenced by shared evolutionary histories. We used a phylogenetic generalized least-squares analysis (PGLS) to test whether phylogeny influences the predictability of genome size from dN/dS ratios and 16S copy number, two variables that have been previously linked to genome size. These results confirm that failure to account for evolutionary history can lead to biased interpretations of genome size predictors. Overall, our results indicate that although bacteria and archaea can rapidly gain and lose genetic material through gene transfers and deletions, respectively, phylogenetic signal for genome size distributions can still be recovered at broad phylogenetic scales that should be taken into account when inferring the drivers of genome size evolution. The evolutionary forces driving genome size in bacteria and archaea have been subject to debate during the last decades. Typically, independent comparative analyses have suggested that unique variables, such as the strength of selection, environmental complexity, and mutation rate, are the main drivers of this trait, without considering for potential biases derived from shared ancestry. Here, we applied a phylogeny-based statistical approach to assess how tightly genome size in bacteria and archaea is linked to evolutionary history. Moreover, we also evaluated the predictability of genome size from the strength of purifying selection and ecological strategy on a broad diversity of bacteria and archaea genomes under a phylogenetic comparative framework. Our approach indicates that despite the ability of bacteria and archaea to rapidly exchange genes, a strong phylogenetic signal to genome size distributions can be recovered at broad phylogenetic scales.
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Affiliation(s)
| | - Frank O. Aylward
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
- Center for Emerging, Zoonotic, and Arthropod-borne Pathogens, Virginia Tech, Blacksburg, Virginia, United States of America
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Marques AT, Tanoeiro L, Duarte A, Gonçalves L, Vítor JMB, Vale FF. Genomic Analysis of Prophages from Klebsiella pneumoniae Clinical Isolates. Microorganisms 2021; 9:2252. [PMID: 34835377 PMCID: PMC8617712 DOI: 10.3390/microorganisms9112252] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/15/2021] [Accepted: 10/25/2021] [Indexed: 12/15/2022] Open
Abstract
Klebsiella pneumoniae is an increasing threat to public health and represents one of the most concerning pathogens involved in life-threatening infections. The resistant and virulence determinants are coded by mobile genetic elements which can easily spread between bacteria populations and co-evolve with its genomic host. In this study, we present the full genomic sequences, insertion sites and phylogenetic analysis of 150 prophages found in 40 K. pneumoniae clinical isolates obtained from an outbreak in a Portuguese hospital. All strains harbored at least one prophage and we identified 104 intact prophages (69.3%). The prophage size ranges from 29.7 to 50.6 kbp, coding between 32 and 78 putative genes. The prophage GC content is 51.2%, lower than the average GC content of 57.1% in K. pneumoniae. Complete prophages were classified into three families in the order Caudolovirales: Myoviridae (59.6%), Siphoviridae (38.5%) and Podoviridae (1.9%). In addition, an alignment and phylogenetic analysis revealed nine distinct clusters. Evidence of recombination was detected within the genome of some prophages but, in most cases, proteins involved in viral structure, transcription, replication and regulation (lysogenic/lysis) were maintained. These results support the knowledge that prophages are diverse and widely disseminated in K. pneumoniae genomes, contributing to the evolution of this species and conferring additional phenotypes. Moreover, we identified K. pneumoniae prophages in a set of endolysin genes, which were found to code for proteins with lysozyme activity, cleaving the β-1,4 linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in the peptidoglycan network and thus representing genes with the potential for lysin phage therapy.
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Affiliation(s)
- Andreia T. Marques
- Pathogen Genome Bioinformatics and Computational Biology, Research Institute for Medicines (iMed-ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal; (L.T.); (J.M.B.V.)
| | - Luís Tanoeiro
- Pathogen Genome Bioinformatics and Computational Biology, Research Institute for Medicines (iMed-ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal; (L.T.); (J.M.B.V.)
| | - Aida Duarte
- Faculty of Pharmacy, Universidade de Lisboa, Av. Gama Pinto, 1649-003 Lisboa, Portugal;
- Centro de Investigação Interdisciplinar Egas Moniz, Instituto Universitário Egas Moniz, 2829-511 Monte da Caparica, Portugal
| | - Luisa Gonçalves
- Clinical Pathology Unit, Hospital SAMS, Cidade de Gabela, 1849-017 Lisboa, Portugal;
| | - Jorge M. B. Vítor
- Pathogen Genome Bioinformatics and Computational Biology, Research Institute for Medicines (iMed-ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal; (L.T.); (J.M.B.V.)
| | - Filipa F. Vale
- Pathogen Genome Bioinformatics and Computational Biology, Research Institute for Medicines (iMed-ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal; (L.T.); (J.M.B.V.)
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9
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Goodall DJ, Jameson KH, Hawkins M, Rudolph CJ. A Fork Trap in the Chromosomal Termination Area Is Highly Conserved across All Escherichia coli Phylogenetic Groups. Int J Mol Sci 2021; 22:ijms22157928. [PMID: 34360694 PMCID: PMC8347550 DOI: 10.3390/ijms22157928] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 12/26/2022] Open
Abstract
Termination of DNA replication, the final stage of genome duplication, is surprisingly complex, and failures to bring DNA synthesis to an accurate conclusion can impact genome stability and cell viability. In Escherichia coli, termination takes place in a specialised termination area opposite the origin. A 'replication fork trap' is formed by unidirectional fork barriers via the binding of Tus protein to genomic ter sites. Such a fork trap system is found in some bacterial species, but it appears not to be a general feature of bacterial chromosomes. The biochemical properties of fork trap systems have been extensively characterised, but little is known about their precise physiological roles. In this study, we compare locations and distributions of ter terminator sites in E. coli genomes across all phylogenetic groups, including Shigella. Our analysis shows that all ter sites are highly conserved in E. coli, with slightly more variability in the Shigella genomes. Our sequence analysis of ter sites and Tus proteins shows that the fork trap is likely to be active in all strains investigated. In addition, our analysis shows that the dif chromosome dimer resolution site is consistently located between the innermost ter sites, even if rearrangements have changed the location of the innermost termination area. Our data further support the idea that the replication fork trap has an important physiological role that provides an evolutionary advantage.
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Affiliation(s)
- Daniel J. Goodall
- Division of Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK;
| | - Katie H. Jameson
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK; (K.H.J.); (M.H.)
| | - Michelle Hawkins
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK; (K.H.J.); (M.H.)
| | - Christian J. Rudolph
- Division of Biosciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK;
- Correspondence:
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10
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Touchon M, Perrin A, de Sousa JAM, Vangchhia B, Burn S, O’Brien CL, Denamur E, Gordon D, Rocha EPC. Phylogenetic background and habitat drive the genetic diversification of Escherichia coli. PLoS Genet 2020; 16:e1008866. [PMID: 32530914 PMCID: PMC7314097 DOI: 10.1371/journal.pgen.1008866] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 06/24/2020] [Accepted: 05/18/2020] [Indexed: 12/15/2022] Open
Abstract
Escherichia coli is mostly a commensal of birds and mammals, including humans, where it can act as an opportunistic pathogen. It is also found in water and sediments. We investigated the phylogeny, genetic diversification, and habitat-association of 1,294 isolates representative of the phylogenetic diversity of more than 5,000 isolates from the Australian continent. Since many previous studies focused on clinical isolates, we investigated mostly other isolates originating from humans, poultry, wild animals and water. These strains represent the species genetic diversity and reveal widespread associations between phylogroups and isolation sources. The analysis of strains from the same sequence types revealed very rapid change of gene repertoires in the very early stages of divergence, driven by the acquisition of many different types of mobile genetic elements. These elements also lead to rapid variations in genome size, even if few of their genes rise to high frequency in the species. Variations in genome size are associated with phylogroup and isolation sources, but the latter determine the number of MGEs, a marker of recent transfer, suggesting that gene flow reinforces the association of certain genetic backgrounds with specific habitats. After a while, the divergence of gene repertoires becomes linear with phylogenetic distance, presumably reflecting the continuous turnover of mobile element and the occasional acquisition of adaptive genes. Surprisingly, the phylogroups with smallest genomes have the highest rates of gene repertoire diversification and fewer but more diverse mobile genetic elements. This suggests that smaller genomes are associated with higher, not lower, turnover of genetic information. Many of these genomes are from freshwater isolates and have peculiar traits, including a specific capsule, suggesting adaptation to this environment. Altogether, these data contribute to explain why epidemiological clones tend to emerge from specific phylogenetic groups in the presence of pervasive horizontal gene transfer across the species. Previous large scale studies on the evolution of E. coli focused on clinical isolates emphasizing virulence and antibiotic resistance in medically important lineages. Yet, most E. coli strains are either human commensals or not associated with humans at all. Here, we analyzed a large collection of non-clinical isolates of the species to assess the mechanisms of gene repertoire diversification in the light of isolation sources and phylogeny. We show that gene repertoires evolve so rapidly by the high turnover of mobile genetic elements that epidemiologically indistinguishable strains can be phenotypically extremely heterogeneous, illustrating the velocity of bacterial adaptation and the importance of accounting for the information on the whole genome at the epidemiological scale. Phylogeny and habitat shape the genetic diversification of E. coli to similar extents. Surprisingly, freshwater strains seem specifically adapted to this environment, breaking the paradigm that E. coli environmental isolates are systematically fecal contaminations. As a consequence, the evolution of this species is also shaped by environmental habitats, and it may diversify by acquiring genes and mobile elements from environmental bacteria (and not just from gut bacteria). This may facilitate the acquisition of virulence factors and antibiotic resistance in the strains that become pathogenic.
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Affiliation(s)
- Marie Touchon
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, 25-28 rue Dr Roux, Paris, 75015, France
- * E-mail:
| | - Amandine Perrin
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, 25-28 rue Dr Roux, Paris, 75015, France
- Sorbonne Université, Collège doctoral, F-75005 Paris, France
| | - Jorge André Moura de Sousa
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, 25-28 rue Dr Roux, Paris, 75015, France
| | - Belinda Vangchhia
- Ecology and Evolution, Research School of Biology, The Australian National University, Acton, ACT, Australia
- Department of Veterinary Microbiology, College of Veterinary Sciences & Animal Husbandry, Central Agricultural University, Selesih, Aizawl, Mizoram, India
| | - Samantha Burn
- Ecology and Evolution, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Claire L. O’Brien
- School of Medicine, University of Wollongong, Northfields Ave Wollongong, Australia
| | - Erick Denamur
- Université de Paris, IAME, UMR 1137, INSERM, Paris, 75018, France
- AP-HP, Laboratoire de Génétique Moléculaire, Hôpital Bichat, 75018, Paris, France
| | - David Gordon
- Ecology and Evolution, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Eduardo PC Rocha
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, 25-28 rue Dr Roux, Paris, 75015, France
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11
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Goodhead I, Blow F, Brownridge P, Hughes M, Kenny J, Krishna R, McLean L, Pongchaikul P, Beynon R, Darby AC. Large-scale and significant expression from pseudogenes in Sodalis glossinidius - a facultative bacterial endosymbiont. Microb Genom 2020; 6:e000285. [PMID: 31922467 PMCID: PMC7067036 DOI: 10.1099/mgen.0.000285] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 07/10/2019] [Indexed: 01/30/2023] Open
Abstract
The majority of bacterial genomes have high coding efficiencies, but there are some genomes of intracellular bacteria that have low gene density. The genome of the endosymbiont Sodalis glossinidius contains almost 50 % pseudogenes containing mutations that putatively silence them at the genomic level. We have applied multiple 'omic' strategies, combining Illumina and Pacific Biosciences Single-Molecule Real-Time DNA sequencing and annotation, stranded RNA sequencing and proteome analysis to better understand the transcriptional and translational landscape of Sodalis pseudogenes, and potential mechanisms for their control. Between 53 and 74 % of the Sodalis transcriptome remains active in cell-free culture. The mean sense transcription from coding domain sequences (CDSs) is four times greater than that from pseudogenes. Comparative genomic analysis of six Illumina-sequenced Sodalis isolates from different host Glossina species shows pseudogenes make up ~40 % of the 2729 genes in the core genome, suggesting that they are stable and/or that Sodalis is a recent introduction across the genus Glossina as a facultative symbiont. These data shed further light on the importance of transcriptional and translational control in deciphering host-microbe interactions. The combination of genomics, transcriptomics and proteomics gives a multidimensional perspective for studying prokaryotic genomes with a view to elucidating evolutionary adaptation to novel environmental niches.
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Affiliation(s)
- Ian Goodhead
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
- School of Science, Engineering and Environment, Peel Building, University of Salford, M5 4WT, UK
| | - Frances Blow
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
- Department of Entomology, Cornell University, Ithaca 14853, NY, USA
| | - Philip Brownridge
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
| | - Margaret Hughes
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
- Centre for Genomic Research, Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
| | - John Kenny
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
- Centre for Genomic Research, Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
| | - Ritesh Krishna
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
- IBM Research UK, STFC Daresbury Laboratory, Warrington, WA4 4AD, UK
| | - Lynn McLean
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
| | - Pisut Pongchaikul
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
| | - Rob Beynon
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
| | - Alistair C. Darby
- Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
- Centre for Genomic Research, Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK
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12
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Chavarro-Portillo B, Soto CY, Guerrero MI. Mycobacterium leprae's evolution and environmental adaptation. Acta Trop 2019; 197:105041. [PMID: 31152726 DOI: 10.1016/j.actatropica.2019.105041] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 05/28/2019] [Accepted: 05/28/2019] [Indexed: 11/24/2022]
Abstract
Leprosy is an ancient disease caused by the acid-fast bacillus Mycobacterium leprae, also known as Hansen's bacillus. M. leprae is an obligate intracellular microorganism with a marked Schwann cell tropism and is the only human pathogen capable of invading the superficial peripheral nerves. The transmission mechanism of M. leprae is not fully understood; however, the nasal mucosa is accepted as main route of M. leprae entry to the human host. The complete sequencing and the comparative genome analysis show that M. leprae underwent a genome reductive evolution process, as result of lifestyle change and adaptation to different environments; some of lost genes are homologous to those of host cells. Thus, M. leprae reduced its genome size to 3.3 Mbp, contributing to obtain the lowest GC content (approximately 58%) among mycobacteria. The M. leprae genome contains 1614 open reading frames coding for functional proteins, and 1310 pseudogenes corresponding to 41% of the genome, approximately. Comparative analyses to different microorganisms showed that M. leprae possesses the highest content of pseudogenes among pathogenic and non-pathogenic bacteria and archaea. The pathogen adaptation into host cells, as the Schwann cells, brought about the reduction of the genome and induced multiple gene inactivation. The present review highlights the characteristics of genome's reductive evolution that M. leprae experiences in the genetic aspects compared with other pathogens. The possible mechanisms of pseudogenes formation are discussed.
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13
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Ramisetty BCM, Sudhakari PA. Bacterial 'Grounded' Prophages: Hotspots for Genetic Renovation and Innovation. Front Genet 2019; 10:65. [PMID: 30809245 PMCID: PMC6379469 DOI: 10.3389/fgene.2019.00065] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 01/24/2019] [Indexed: 01/07/2023] Open
Abstract
Bacterial genomes are highly plastic allowing the generation of variants through mutations and acquisition of genetic information. The fittest variants are then selected by the econiche thereby allowing the bacterial adaptation and colonization of the habitat. Larger genomes, however, may impose metabolic burden and hence bacterial genomes are optimized by the loss of frivolous genetic information. The activity of temperate bacteriophages has acute consequences on the bacterial population as well as the bacterial genome through lytic and lysogenic cycles. Lysogeny is a selective advantage as the prophage provides immunity to the lysogen against secondary phage attack. Since the non-lysogens are eliminated by the lytic phages, lysogens multiply and colonize the habitat. Nevertheless, all lysogens have an imminent risk of lytic cycle activation and cell lysis. However, a mutation in the attachment sites or in the genes that encode the specific recombinase responsible for prophage excision could result in 'grounding' of the prophage. Since the lysogens with grounded prophage are immune to respective phage infection as well as dodge the induction of lytic cycle, we hypothesize that the selection of these mutant lysogens is favored relative to their normal lysogenic counterparts. These grounded prophages offer several advantages to the bacterial genome evolution through propensity for genetic variations including inversions, deletions, and insertions via horizontal gene transfer. We propose that the grounded prophages expedite bacterial genome evolution by acting as 'genetic buffer zones' thereby increasing the frequency as well as the diversity of variations on which natural selection favors the beneficial variants. The grounded prophages are also hotspots for horizontal gene transfer wherein several ecologically significant genes such as those involved in stress tolerance, antimicrobial resistance, and novel metabolic pathways, are integrated. Moreover, the high frequency of genetic changes within prophages also allows proportionate probability for the de novo genesis of genetic information. Through sequence analyses of well-characterized E. coli prophages we exemplify various roles of grounded prophages in E. coli ecology and evolution. Therefore, the temperate prophages are one of the most significant drivers of bacterial genome evolution and sites of biogenesis of genetic information.
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Affiliation(s)
- Bhaskar Chandra Mohan Ramisetty
- Laboratory of Molecular Biology and Evolution, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, India
| | - Pavithra Anantharaman Sudhakari
- Laboratory of Molecular Biology and Evolution, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, India
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14
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Anand A, Olson CA, Yang L, Sastry AV, Catoiu E, Choudhary KS, Phaneuf PV, Sandberg TE, Xu S, Hefner Y, Szubin R, Feist AM, Palsson BO. Pseudogene repair driven by selection pressure applied in experimental evolution. Nat Microbiol 2019; 4:386-389. [DOI: 10.1038/s41564-018-0340-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 12/05/2018] [Indexed: 11/09/2022]
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15
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Yao J, Guo Y, Wang P, Zeng Z, Li B, Tang K, Liu X, Wang X. Type II toxin/antitoxin system ParE SO /CopA SO stabilizes prophage CP4So in Shewanella oneidensis. Environ Microbiol 2018; 20:1224-1239. [PMID: 29411516 DOI: 10.1111/1462-2920.14068] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 02/03/2018] [Accepted: 02/04/2018] [Indexed: 12/15/2022]
Abstract
Toxin/antitoxin (TA) loci are commonly found in mobile genetic elements such as plasmids and prophages. However, the physiological functions of these TA loci in prophages and cross-regulation among these TA loci remain largely unexplored. Here, we characterized a newly discovered type II TA pair, ParESO /CopASO , in the CP4So prophage in Shewanella oneidensis. We demonstrated that ParESO /CopASO plays a critical role in the maintenance of CP4So in host cells after its excision. The toxin ParESO inhibited cell growth, resulting in filamentous growth and eventually cell death. The antitoxin CopASO neutralized the toxicity of ParESO through direct protein-protein interactions and repressed transcription of the TA operon by binding to a DNA motif in the promoter region containing two inverted repeats [5'-GTANTAC (N)3 GTANTAC-3']. CopASO also repressed transcription of another TA system PemKSO /PemISO in megaplasmid pMR-1 of S. oneidensis through binding to a highly similar DNA motif in its promoter region. CopASO homologs are widely spread in Shewanella and other Proteobacteria, either as a component of a TA pair or as orphan antitoxins. Our study thus illustrated the cross-regulation of the TA systems in different mobile genetic elements and expanded our understanding of the physiological function of TA systems.
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Affiliation(s)
- Jianyun Yao
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, People's Republic of China.,University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yunxue Guo
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, People's Republic of China
| | - Pengxia Wang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, People's Republic of China
| | - Zhenshun Zeng
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, People's Republic of China
| | - Baiyuan Li
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, People's Republic of China
| | - Kaihao Tang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, People's Republic of China
| | - Xiaoxiao Liu
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, People's Republic of China
| | - Xiaoxue Wang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, People's Republic of China
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16
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Sharmin D, Guo Y, Nishizawa T, Ohshima S, Sato Y, Takashima Y, Narisawa K, Ohta H. Comparative Genomic Insights into Endofungal Lifestyles of Two Bacterial Endosymbionts, Mycoavidus cysteinexigens and Burkholderia rhizoxinica. Microbes Environ 2018. [PMID: 29540638 PMCID: PMC5877345 DOI: 10.1264/jsme2.me17138] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Endohyphal bacteria (EHB), dwelling within fungal hyphae, markedly affect the growth and metabolic potential of their hosts. To date, two EHB belonging to the family Burkholderiaceae have been isolated and characterized as new taxa, Burkholderia rhizoxinica (HKI 454T) and Mycoavidus cysteinexigens (B1-EBT), in Japan. Metagenome sequencing was recently reported for Mortierella elongata AG77 together with its endosymbiont M. cysteinexigens (Mc-AG77) from a soil/litter sample in the USA. In the present study, we elucidated the complete genome sequence of B1-EBT and compared it with those of Mc-AG77 and HKI 454T. The genomes of B1-EBT and Mc-AG77 contained a higher level of prophage sequences and were markedly smaller than that of HKI 454T. Although the B1-EBT and Mc-AG77 genomes lacked the chitinolytic enzyme genes responsible for invasion into fungal cells, they contained several predicted toxin-antitoxin systems including an insecticidal toxin complex and PIN domain imposing an addiction-like mechanism essential for endohyphal growth control during host colonization. Despite the different host fungi, the alignment of amino acid sequences showed that the HKI 454T genome consisted of 1,265 (32.6%) and 1,221 (31.5%) orthologous coding sequences (CDSs) with those of B1-EBT and Mc-AG77, respectively. This comparative study of three phylogenetically associated endosymbionts has provided insights into their origin and evolution, and suggests the later bacterial invasion and adaptation of B1-EBT to its host metabolism.
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Affiliation(s)
- Dilruba Sharmin
- Ibaraki University College of Agriculture, Department of Bioresource Science
| | - Yong Guo
- Ibaraki University College of Agriculture, Department of Bioresource Science
| | - Tomoyasu Nishizawa
- Ibaraki University College of Agriculture, Department of Bioresource Science.,United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology
| | - Shoko Ohshima
- Ibaraki University College of Agriculture, Department of Bioresource Science
| | - Yoshinori Sato
- Center for Conservation and Restoration Techniques, Tokyo National Research Institute for Cultural Properties
| | - Yusuke Takashima
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology
| | - Kazuhiko Narisawa
- Ibaraki University College of Agriculture, Department of Bioresource Science.,United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology
| | - Hiroyuki Ohta
- Ibaraki University College of Agriculture, Department of Bioresource Science.,United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology
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17
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Gilcrease EB, Casjens SR. The genome sequence of Escherichia coli tailed phage D6 and the diversity of Enterobacteriales circular plasmid prophages. Virology 2018; 515:203-214. [PMID: 29304472 PMCID: PMC5800970 DOI: 10.1016/j.virol.2017.12.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 12/15/2017] [Accepted: 12/17/2017] [Indexed: 11/29/2022]
Abstract
The temperate Escherichia coli bacteriophage D6 can exist as a circular plasmid prophage, and we report here its 91,159bp complete genome sequence. It is a distant relative of the well-studied phage P1, but it is sufficiently different that it typifies a previously undescribed tailed phage type or cluster. Examination of the database of bacterial genome sequences revealed that phage P1 and D6 prophage plasmids are common in the Enterobacteriales, and in addition, previously described Salmonella phage SSU5 represents a different type of temperate tailed phage with a circular plasmid prophage that is also very common in this host order. This analysis also discovered additional divergent clusters of putative circular plasmid prophages within the two larger P1 and SSU5 groups (superclusters) that inhabit the Enterobacteriales as well as bacteria in several other orders in the Gamma-proteobacteria class. Very few of these sequences are annotated as putative prophages.
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Affiliation(s)
- Eddie B Gilcrease
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Sherwood R Casjens
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Biology Department, University of Utah, Salt Lake City, UT 84112, USA.
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18
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Shakya M, Soucy SM, Zhaxybayeva O. Insights into origin and evolution of α-proteobacterial gene transfer agents. Virus Evol 2017; 3:vex036. [PMID: 29250433 PMCID: PMC5721377 DOI: 10.1093/ve/vex036] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Several bacterial and archaeal lineages produce nanostructures that morphologically resemble small tailed viruses, but, unlike most viruses, contain apparently random pieces of the host genome. Since these elements can deliver the packaged DNA to other cells, they were dubbed gene transfer agents (GTAs). Because many genes involved in GTA production have viral homologs, it has been hypothesized that the GTA ancestor was a virus. Whether GTAs represent an atypical virus, a defective virus, or a virus co-opted by the prokaryotes for some function, remains to be elucidated. To evaluate these possibilities, we examined the distribution and evolutionary histories of genes that encode a GTA in the α-proteobacterium Rhodobacter capsulatus (RcGTA). We report that although homologs of many individual RcGTA genes are abundant across bacteria and their viruses, RcGTA-like genomes are mainly found in one subclade of α-proteobacteria. When compared with the viral homologs, genes of the RcGTA-like genomes evolve significantly slower, and do not have higher %A+T nucleotides than their host chromosomes. Moreover, they appear to reside in stable regions of the bacterial chromosomes that are generally conserved across taxonomic orders. These findings argue against RcGTA being an atypical or a defective virus. Our phylogenetic analyses suggest that RcGTA ancestor likely originated in the lineage that gave rise to contemporary α-proteobacterial orders Rhizobiales, Rhodobacterales, Caulobacterales, Parvularculales, and Sphingomonadales, and since that time the RcGTA-like element has co-evolved with its host chromosomes. Such evolutionary history is compatible with maintenance of these elements by bacteria due to some selective advantage. As for many other prokaryotic traits, horizontal gene transfer played a substantial role in the evolution of RcGTA-like elements, not only in shaping its genome components within the orders, but also in occasional dissemination of RcGTA-like regions across the orders and even to different bacterial phyla.
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Affiliation(s)
- Migun Shakya
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03755, USA
| | - Shannon M Soucy
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03755, USA
| | - Olga Zhaxybayeva
- Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03755, USA.,Department of Computer Science, Dartmouth College, 6211 Sudikoff Lab, Hanover, NH 03755, USA
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19
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Abedon ST, LeJeune JT. Why Bacteriophage Encode Exotoxins and other Virulence Factors. Evol Bioinform Online 2017. [DOI: 10.1177/117693430500100001] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This study considers gene location within bacteria as a function of genetic element mobility. Our emphasis is on prophage encoding of bacterial virulence factors (VFs). At least four mechanisms potentially contribute to phage encoding of bacterial VFs: (i) Enhanced gene mobility could result in greater VF gene representation within bacterial populations. We question, though, why certain genes but not others might benefit from this mobility. (ii) Epistatic interactions—between VF genes and phage genes that enhance VF utility to bacteria—could maintain phage genes via selection acting on individual, VF-expressing bacteria. However, is this mechanism sufficient to maintain the rest of phage genomes or, without gene co-regulation, even genetic linkage between phage and VF genes? (iii) Phage could amplify VFs during disease progression by carrying them to otherwise commensal bacteria colocated within the same environment. However, lytic phage kill bacteria, thus requiring assumptions of inclusive fitness within bacterial populations to explain retention of phage-mediated VF amplification for the sake of bacterial utility. Finally, (iv) phage-encoded VFs could enhance phage Darwinian fitness, particularly by acting as ecosystem-modifying agents. That is, VF-supplied nutrients could enhance phage growth by increasing the density or by improving the physiology of phage-susceptible bacteria. Alternatively, VF-mediated break down of diffusion-inhibiting spatial structure found within the multicellular bodies of host organisms could augment phage dissemination to new bacteria or to environments. Such phage-fitness enhancing mechanisms could apply particularly given VF expression within microbiologically heterogeneous environments, ie, ones where phage have some reasonable potential to acquire phage-susceptible bacteria.
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Affiliation(s)
| | - Jeffrey T. LeJeune
- Food Animal Health Research Program, Ohio State University, Wooster, Ohio
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20
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Murungi EK, Kariithi HM. Genome-Wide Identification and Evolutionary Analysis of Sarcocystis neurona Protein Kinases. Pathogens 2017; 6:pathogens6010012. [PMID: 28335576 PMCID: PMC5371900 DOI: 10.3390/pathogens6010012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/10/2017] [Accepted: 03/17/2017] [Indexed: 02/07/2023] Open
Abstract
The apicomplexan parasite Sarcocystis neurona causes equine protozoal myeloencephalitis (EPM), a degenerative neurological disease of horses. Due to its host range expansion, S. neurona is an emerging threat that requires close monitoring. In apicomplexans, protein kinases (PKs) have been implicated in a myriad of critical functions, such as host cell invasion, cell cycle progression and host immune response evasion. Here, we used various bioinformatics methods to define the kinome of S. neurona and phylogenetic relatedness of its PKs to other apicomplexans. We identified 97 putative PKs clustering within the various eukaryotic kinase groups. Although containing the universally-conserved PKA (AGC group), S. neurona kinome was devoid of PKB and PKC. Moreover, the kinome contains the six-conserved apicomplexan CDPKs (CAMK group). Several OPK atypical kinases, including ROPKs 19A, 27, 30, 33, 35 and 37 were identified. Notably, S. neurona is devoid of the virulence-associated ROPKs 5, 6, 18 and 38, as well as the Alpha and RIO kinases. Two out of the three S. neurona CK1 enzymes had high sequence similarities to Toxoplasma gondii TgCK1-α and TgCK1-β and the Plasmodium PfCK1. Further experimental studies on the S. neurona putative PKs identified in this study are required to validate the functional roles of the PKs and to understand their involvement in mechanisms that regulate various cellular processes and host-parasite interactions. Given the essentiality of apicomplexan PKs in the survival of apicomplexans, the current study offers a platform for future development of novel therapeutics for EPM, for instance via application of PK inhibitors to block parasite invasion and development in their host.
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Affiliation(s)
- Edwin K Murungi
- Department of Biochemistry and Molecular Biology, Egerton University, P.O. Box 536, 20115 Njoro, Kenya.
| | - Henry M Kariithi
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, P.O. Box 57811, Kaptagat Rd, Loresho, 00200 Nairobi, Kenya.
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Owen SV, Wenner N, Canals R, Makumi A, Hammarlöf DL, Gordon MA, Aertsen A, Feasey NA, Hinton JCD. Characterization of the Prophage Repertoire of African Salmonella Typhimurium ST313 Reveals High Levels of Spontaneous Induction of Novel Phage BTP1. Front Microbiol 2017; 8:235. [PMID: 28280485 PMCID: PMC5322425 DOI: 10.3389/fmicb.2017.00235] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 02/02/2017] [Indexed: 01/30/2023] Open
Abstract
In the past 30 years, Salmonella bloodstream infections have become a significant health problem in sub-Saharan Africa and are responsible for the deaths of an estimated 390,000 people each year. The disease is predominantly caused by a recently described sequence type of Salmonella Typhimurium: ST313, which has a distinctive set of prophage sequences. We have thoroughly characterized the ST313-associated prophages both genetically and experimentally. ST313 representative strain D23580 contains five full-length prophages: BTP1, Gifsy-2D23580, ST64BD23580, Gifsy-1D23580, and BTP5. We show that common S. Typhimurium prophages Gifsy-2, Gifsy-1, and ST64B are inactivated in ST313 by mutations. Prophage BTP1 was found to be a functional novel phage, and the first isolate of the proposed new species "Salmonella virus BTP1", belonging to the P22virus genus. Surprisingly, ∼109 BTP1 virus particles per ml were detected in the supernatant of non-induced, stationary-phase cultures of strain D23580, representing the highest spontaneously induced phage titer so far reported for a bacterial prophage. High spontaneous induction is shown to be an intrinsic property of prophage BTP1, and indicates the phage-mediated lysis of around 0.2% of the lysogenic population. The fact that BTP1 is highly conserved in ST313 poses interesting questions about the potential fitness costs and benefits of novel prophages in epidemic S. Typhimurium ST313.
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Affiliation(s)
- Siân V Owen
- Institute of Integrative Biology, University of Liverpool Liverpool, UK
| | - Nicolas Wenner
- Institute of Integrative Biology, University of Liverpool Liverpool, UK
| | - Rocío Canals
- Institute of Integrative Biology, University of Liverpool Liverpool, UK
| | - Angela Makumi
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, KU Leuven Leuven, Belgium
| | - Disa L Hammarlöf
- Department of Cell and Molecular Biology, Uppsala University Uppsala, Sweden
| | - Melita A Gordon
- Institute of Infection and Global Health, University of LiverpoolLiverpool, UK; Malawi-Liverpool-Wellcome Trust Clinical Research ProgrammeBlantyre, Malawi
| | - Abram Aertsen
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, KU Leuven Leuven, Belgium
| | | | - Jay C D Hinton
- Institute of Integrative Biology, University of Liverpool Liverpool, UK
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Patel S. Drivers of bacterial genomes plasticity and roles they play in pathogen virulence, persistence and drug resistance. INFECTION GENETICS AND EVOLUTION 2016; 45:151-164. [DOI: 10.1016/j.meegid.2016.08.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 08/26/2016] [Accepted: 08/27/2016] [Indexed: 12/11/2022]
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Esposito LA, Gupta S, Streiter F, Prasad A, Dennehy JJ. Evolutionary interpretations of mycobacteriophage biodiversity and host-range through the analysis of codon usage bias. Microb Genom 2016; 2:e000079. [PMID: 28348827 PMCID: PMC5359403 DOI: 10.1099/mgen.0.000079] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 07/18/2016] [Indexed: 12/31/2022] Open
Abstract
In an genomics course sponsored by the Howard Hughes Medical Institute (HHMI), undergraduate students have isolated and sequenced the genomes of more than 1,150 mycobacteriophages, creating the largest database of sequenced bacteriophages able to infect a single host, Mycobacterium smegmatis, a soil bacterium. Genomic analysis indicates that these mycobacteriophages can be grouped into 26 clusters based on genetic similarity. These clusters span a continuum of genetic diversity, with extensive genomic mosaicism among phages in different clusters. However, little is known regarding the primary hosts of these mycobacteriophages in their natural habitats, nor of their broader host ranges. As such, it is possible that the primary host of many newly isolated mycobacteriophages is not M. smegmatis, but instead a range of closely related bacterial species. However, determining mycobacteriophage host range presents difficulties associated with mycobacterial cultivability, pathogenicity and growth. Another way to gain insight into mycobacteriophage host range and ecology is through bioinformatic analysis of their genomic sequences. To this end, we examined the correlations between the codon usage biases of 199 different mycobacteriophages and those of several fully sequenced mycobacterial species in order to gain insight into the natural host range of these mycobacteriophages. We find that UPGMA clustering tends to match, but not consistently, clustering by shared nucleotide sequence identify. In addition, analysis of GC content, tRNA usage and correlations between mycobacteriophage and mycobacterial codon usage bias suggests that the preferred host of many clustered mycobacteriophages is not M. smegmatis but other, as yet unknown, members of the mycobacteria complex or closely allied bacterial species.
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Affiliation(s)
| | - Swati Gupta
- Biology Department, Queens College, Queens, NY 11367, USA
| | | | - Ashley Prasad
- Biology Department, Queens College, Queens, NY 11367, USA
| | - John J. Dennehy
- Biology Department, Queens College, Queens, NY 11367, USA
- Biology PhD Program, The Graduate Center of the City University of New York, New York, NY 10016, USA
- Correspondence John J. Dennehy ()
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Abstract
Almost all cellular life forms are hosts to diverse genetic parasites with various levels of autonomy including plasmids, transposons and viruses. Theoretical modeling of the evolution of primordial replicators indicates that parasites (cheaters) necessarily evolve in such systems and can be kept at bay primarily via compartmentalization. Given the (near) ubiquity, abundance and diversity of genetic parasites, the question becomes pertinent: are such parasites intrinsic to life? At least in prokaryotes, the persistence of parasites is linked to the rate of horizontal gene transfer (HGT). We mathematically derive the threshold value of the minimal transfer rate required for selfish element persistence, depending on the element duplication and loss rates as well as the cost to the host. Estimation of the characteristic gene duplication, loss and transfer rates for transposons, plasmids and virus-related elements in multiple groups of diverse bacteria and archaea indicates that most of these rates are compatible with the long term persistence of parasites. Notably, a small but non-zero rate of HGT is also required for the persistence of non-parasitic genes. We hypothesize that cells cannot tune their horizontal transfer rates to be below the threshold required for parasite persistence without experiencing highly detrimental side-effects. As a lower boundary to the minimum DNA transfer rate that a cell can withstand, we consider the process of genome degradation and mutational meltdown of populations through Muller's ratchet. A numerical assessment of this hypothesis suggests that microbial populations cannot purge parasites while escaping Muller's ratchet. Thus, genetic parasites appear to be virtually inevitable in cellular organisms.
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Affiliation(s)
- Jaime Iranzo
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda
| | - Pere Puigbò
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda Present address: Department of Biology, University of Turku, Finland
| | - Alexander E Lobkovsky
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda
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Locating and Activating Molecular 'Time Bombs': Induction of Mycolata Prophages. PLoS One 2016; 11:e0159957. [PMID: 27487243 PMCID: PMC4972346 DOI: 10.1371/journal.pone.0159957] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 07/11/2016] [Indexed: 11/23/2022] Open
Abstract
Little is known about the prevalence, functionality and ecological roles of temperate phages for members of the mycolic acid producing bacteria, the Mycolata. While many lytic phages infective for these organisms have been isolated, and assessed for their suitability for use as biological control agents of activated sludge foaming, no studies have investigated how temperate phages might be induced for this purpose. Bioinformatic analysis using the PHAge Search Tool (PHAST) on Mycolata whole genome sequence data in GenBank for members of the genera Gordonia, Mycobacterium, Nocardia, Rhodococcus, and Tsukamurella revealed 83% contained putative prophage DNA sequences. Subsequent prophage inductions using mitomycin C were conducted on 17 Mycolata strains. This led to the isolation and genome characterization of three novel Caudovirales temperate phages, namely GAL1, GMA1, and TPA4, induced from Gordonia alkanivorans, Gordonia malaquae, and Tsukamurella paurometabola, respectively. All possessed highly distinctive dsDNA genome sequences.
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Abstract
Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g., Lactococcus lactis), probiotic (e.g., several Lactobacillus spp.), and pathogenic (e.g., Enterococcus and Streptococcus spp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the "stressome" of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance.
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Casjens SR, Grose JH. Contributions of P2- and P22-like prophages to understanding the enormous diversity and abundance of tailed bacteriophages. Virology 2016; 496:255-276. [PMID: 27372181 DOI: 10.1016/j.virol.2016.05.022] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 05/25/2016] [Accepted: 05/26/2016] [Indexed: 11/24/2022]
Abstract
We identified 9371 tailed phage prophages of 20 known types in reported complete genome sequences of 3298 bacteria in the Salmonella genus. These include 4758 P2 type and 744 P22 type prophages. The latter prophage types were found in the genome sequences of 127 and 24 bacterial host genera, increasing the known host ranges of phages in these groups by 114 and 20 genera, respectively. These prophage nucleotide sequences displayed much more diversity than was previously known from the 48 P2 and 24 P22 type authentic phages whose genomes have been sequenced. More detailed analysis of these prophage sequences indicated that major capsid protein (MCP) gene exchange between tailed phage clusters or types is extremely rare and that P22 prophage-encoded tailspikes correspond perfectly with their hosts' surface polysaccharide structure; thus, MCP and tailspike sequences accurately predict tailed phage type (and thus lifestyle) and host cell surface polysaccharide structure, respectively.
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Affiliation(s)
- Sherwood R Casjens
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, University of Utah, Salt Lake City, UT 84112, United States; Department of Biology, University of Utah, Salt Lake City, UT 84112, United States.
| | - Julianne H Grose
- Microbiology and Molecular Biology Department, Brigham Young University, Provo, UT 84602, United States.
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Obeng N, Pratama AA, Elsas JDV. The Significance of Mutualistic Phages for Bacterial Ecology and Evolution. Trends Microbiol 2016; 24:440-449. [DOI: 10.1016/j.tim.2015.12.009] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/11/2015] [Accepted: 12/21/2015] [Indexed: 12/16/2022]
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Uhlich GA, Chen CY, Cottrell BJ, Hofmann CS, Yan X, Nguyen L. Stx1prophage excision inEscherichia colistrain PA20 confers strong curli and biofilm formation by restoring nativemlrA. FEMS Microbiol Lett 2016; 363:fnw123. [DOI: 10.1093/femsle/fnw123] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2016] [Indexed: 01/01/2023] Open
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Bisch G, Ogier JC, Médigue C, Rouy Z, Vincent S, Tailliez P, Givaudan A, Gaudriault S. Comparative Genomics between Two Xenorhabdus bovienii Strains Highlights Differential Evolutionary Scenarios within an Entomopathogenic Bacterial Species. Genome Biol Evol 2016; 8:148-60. [PMID: 26769959 PMCID: PMC4758244 DOI: 10.1093/gbe/evv248] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria of the genus Xenorhabdus are symbionts of soil entomopathogenic nematodes of the genus Steinernema. This symbiotic association constitutes an insecticidal complex active against a wide range of insect pests. Within Xenorhabdus bovienii species, the X. bovienii CS03 strain (Xb CS03) is nonvirulent when directly injected into lepidopteran insects, and displays a low virulence when associated with its Steinernema symbiont. The genome of Xb CS03 was sequenced and compared with the genome of a virulent strain, X. bovienii SS-2004 (Xb SS-2004). The genome size and content widely differed between the two strains. Indeed, Xb CS03 had a large genome containing several specific loci involved in the inhibition of competitors, including a few NRPS-PKS loci (nonribosomal peptide synthetases and polyketide synthases) producing antimicrobial molecules. Consistently, Xb CS03 had a greater antimicrobial activity than Xb SS-2004. The Xb CS03 strain contained more pseudogenes than Xb SS-2004. Decay of genes involved in the host invasion and exploitation (toxins, invasins, or extracellular enzymes) was particularly important in Xb CS03. This may provide an explanation for the nonvirulence of the strain when injected into an insect host. We suggest that Xb CS03 and Xb SS-2004 followed divergent evolutionary scenarios to cope with their peculiar life cycle. The fitness strategy of Xb CS03 would involve competitor inhibition, whereas Xb SS-2004 would quickly and efficiently kill the insect host. Hence, Xenorhabdus strains would have widely divergent host exploitation strategies, which impact their genome structure.
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Affiliation(s)
- Gaëlle Bisch
- Diversité, Génomes Et Interactions Microorganismes-Insectes (DGIMI), Institut National De La Recherche Agronomique, Montpellier Cedex, France Diversité, Génomes Et Interactions Microorganismes-Insectes (DGIMI), Université Montpellier, France
| | - Jean-Claude Ogier
- Diversité, Génomes Et Interactions Microorganismes-Insectes (DGIMI), Institut National De La Recherche Agronomique, Montpellier Cedex, France Diversité, Génomes Et Interactions Microorganismes-Insectes (DGIMI), Université Montpellier, France
| | - Claudine Médigue
- CEA, Genoscope & CNRS-UMR 8030, Laboratoire D'analyse Bioinformatique En Génomique Et Métabolisme, Evry Cedex, France
| | - Zoé Rouy
- CEA, Genoscope & CNRS-UMR 8030, Laboratoire D'analyse Bioinformatique En Génomique Et Métabolisme, Evry Cedex, France
| | - Stéphanie Vincent
- CEA, Genoscope & CNRS-UMR 8030, Laboratoire D'analyse Bioinformatique En Génomique Et Métabolisme, Evry Cedex, France
| | - Patrick Tailliez
- Diversité, Génomes Et Interactions Microorganismes-Insectes (DGIMI), Institut National De La Recherche Agronomique, Montpellier Cedex, France Diversité, Génomes Et Interactions Microorganismes-Insectes (DGIMI), Université Montpellier, France
| | - Alain Givaudan
- Diversité, Génomes Et Interactions Microorganismes-Insectes (DGIMI), Institut National De La Recherche Agronomique, Montpellier Cedex, France Diversité, Génomes Et Interactions Microorganismes-Insectes (DGIMI), Université Montpellier, France
| | - Sophie Gaudriault
- Diversité, Génomes Et Interactions Microorganismes-Insectes (DGIMI), Institut National De La Recherche Agronomique, Montpellier Cedex, France Diversité, Génomes Et Interactions Microorganismes-Insectes (DGIMI), Université Montpellier, France
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Abstract
ABSTRACT
The number and diversity of known prokaryotic insertion sequences (IS) have increased enormously since their discovery in the late 1960s. At present the sequences of more than 4000 different IS have been deposited in the specialized ISfinder database. Over time it has become increasingly apparent that they are important actors in the evolution of their host genomes and are involved in sequestering, transmitting, mutating and activating genes, and in the rearrangement of both plasmids and chromosomes. This review presents an overview of our current understanding of these transposable elements (TE), their organization and their transposition mechanism as well as their distribution and genomic impact. In spite of their diversity, they share only a very limited number of transposition mechanisms which we outline here. Prokaryotic IS are but one example of a variety of diverse TE which are being revealed due to the advent of extensive genome sequencing projects. A major conclusion from sequence comparisons of various TE is that frontiers between the different types are becoming less clear. We detail these receding frontiers between different IS-related TE. Several, more specialized chapters in this volume include additional detailed information concerning a number of these.
In a second section of the review, we provide a detailed description of the expanding variety of IS, which we have divided into families for convenience. Our perception of these families continues to evolve and families emerge regularly as more IS are identified. This section is designed as an aid and a source of information for consultation by interested specialist readers.
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Hertel R, Rodríguez DP, Hollensteiner J, Dietrich S, Leimbach A, Hoppert M, Liesegang H, Volland S. Genome-based identification of active prophage regions by next generation sequencing in Bacillus licheniformis DSM13. PLoS One 2015; 10:e0120759. [PMID: 25811873 PMCID: PMC4374763 DOI: 10.1371/journal.pone.0120759] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 01/26/2015] [Indexed: 11/18/2022] Open
Abstract
Prophages are viruses, which have integrated their genomes into the genome of a bacterial host. The status of the prophage genome can vary from fully intact with the potential to form infective particles to a remnant state where only a few phage genes persist. Prophages have impact on the properties of their host and are therefore of great interest for genomic research and strain design. Here we present a genome- and next generation sequencing (NGS)-based approach for identification and activity evaluation of prophage regions. Seven prophage or prophage-like regions were identified in the genome of Bacillus licheniformis DSM13. Six of these regions show similarity to members of the Siphoviridae phage family. The remaining region encodes the B. licheniformis orthologue of the PBSX prophage from Bacillus subtilis. Analysis of isolated phage particles (induced by mitomycin C) from the wild-type strain and prophage deletion mutant strains revealed activity of the prophage regions BLi_Pp2 (PBSX-like), BLi_Pp3 and BLi_Pp6. In contrast to BLi_Pp2 and BLi_Pp3, neither phage DNA nor phage particles of BLi_Pp6 could be visualized. However, the ability of prophage BLi_Pp6 to generate particles could be confirmed by sequencing of particle-protected DNA mapping to prophage locus BLi_Pp6. The introduced NGS-based approach allows the investigation of prophage regions and their ability to form particles. Our results show that this approach increases the sensitivity of prophage activity analysis and can complement more conventional approaches such as transmission electron microscopy (TEM).
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Affiliation(s)
- Robert Hertel
- Georg-August University Göttingen, Institute of Microbiology and Genetics, Department of Genomic and Applied Microbiology, Göttingen, Germany
| | - David Pintor Rodríguez
- Georg-August University Göttingen, Institute of Microbiology and Genetics, Department of Genomic and Applied Microbiology, Göttingen, Germany
| | - Jacqueline Hollensteiner
- Georg-August University Göttingen, Institute of Microbiology and Genetics, Department of Genomic and Applied Microbiology, Göttingen, Germany
| | - Sascha Dietrich
- Georg-August University Göttingen, Institute of Microbiology and Genetics, Department of Genomic and Applied Microbiology, Göttingen, Germany
| | - Andreas Leimbach
- Georg-August University Göttingen, Institute of Microbiology and Genetics, Department of Genomic and Applied Microbiology, Göttingen, Germany
| | - Michael Hoppert
- Georg-August University Göttingen, Institute of Microbiology and Genetics, Department of Genomic and Applied Microbiology, Göttingen, Germany
| | - Heiko Liesegang
- Georg-August University Göttingen, Institute of Microbiology and Genetics, Department of Genomic and Applied Microbiology, Göttingen, Germany
| | - Sonja Volland
- Georg-August University Göttingen, Institute of Microbiology and Genetics, Department of Genomic and Applied Microbiology, Göttingen, Germany
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Jung J, Park W. Acinetobacter species as model microorganisms in environmental microbiology: current state and perspectives. Appl Microbiol Biotechnol 2015; 99:2533-48. [PMID: 25693672 DOI: 10.1007/s00253-015-6439-y] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 01/23/2015] [Accepted: 01/26/2015] [Indexed: 01/11/2023]
Abstract
Acinetobacter occupies an important position in nature because of its ubiquitous presence in diverse environments such as soils, fresh water, oceans, sediments, and contaminated sites. Versatile metabolic characteristics allow species of this genus to catabolize a wide range of natural compounds, implying active participation in the nutrient cycle in the ecosystem. On the other hand, multi-drug-resistant Acinetobacter baumannii causing nosocomial infections with high mortality has been raising serious concerns in medicine. Due to the ecological and clinical importance of the genus, Acinetobacter was proposed as a model microorganism for environmental microbiological studies, pathogenicity tests, and industrial production of chemicals. For these reasons, Acinetobacter has attracted significant attention in scientific and biotechnological fields, but only limited research areas such as natural transformation and aromatic compound degradation have been intensively investigated, while important physiological characteristics including quorum sensing, motility, and stress response have been neglected. The aim of this review is to summarize the recent achievements in Acinetobacter research with a special focus on strain DR1 and to compare the similarities and differences between species or other genera. Research areas that require more attention in future research are also suggested.
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Affiliation(s)
- Jaejoon Jung
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 136-713, Republic of Korea
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Abstract
Microbes produce a huge array of secondary metabolites endowed with important ecological functions. These molecules, which can be catalogued as natural products, have long been exploited in medical fields as antibiotics, anticancer and anti-infective agents. Recent years have seen considerable advances in elucidating natural-product biosynthesis and many drugs used today are natural products or natural-product derivatives. The major contribution to recent knowledge came from application of genomics to secondary metabolism and was facilitated by all relevant genes being organised in a contiguous DNA segment known as gene cluster. Clustering of genes regulating biosynthesis in bacteria is virtually universal. Modular gene clusters can be mixed and matched during evolution to generate structural diversity in natural products. Biosynthesis of many natural products requires the participation of complex molecular machines known as polyketide synthases and non-ribosomal peptide synthetases. Discovery of new evolutionary links between the polyketide synthase and fatty acid synthase pathways may help to understand the selective advantages that led to evolution of secondary-metabolite biosynthesis within bacteria. Secondary metabolites confer selective advantages, either as antibiotics or by providing a chemical language that allows communication among species, with other organisms and their environment. Herewith, we discuss these aspects focusing on the most clinically relevant bioactive molecules, the thiotemplated modular systems that include polyketide synthases, non-ribosomal peptide synthetases and fatty acid synthases. We begin by describing the evolutionary and physiological role of marine natural products, their structural/functional features, mechanisms of action and biosynthesis, then turn to genomic and metagenomic approaches, highlighting how the growing body of information on microbial natural products can be used to address fundamental problems in environmental evolution and biotechnology.
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Medema MH, Cimermancic P, Sali A, Takano E, Fischbach MA. A systematic computational analysis of biosynthetic gene cluster evolution: lessons for engineering biosynthesis. PLoS Comput Biol 2014; 10:e1004016. [PMID: 25474254 PMCID: PMC4256081 DOI: 10.1371/journal.pcbi.1004016] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 10/31/2014] [Indexed: 01/04/2023] Open
Abstract
Bacterial secondary metabolites are widely used as antibiotics, anticancer drugs, insecticides and food additives. Attempts to engineer their biosynthetic gene clusters (BGCs) to produce unnatural metabolites with improved properties are often frustrated by the unpredictability and complexity of the enzymes that synthesize these molecules, suggesting that genetic changes within BGCs are limited by specific constraints. Here, by performing a systematic computational analysis of BGC evolution, we derive evidence for three findings that shed light on the ways in which, despite these constraints, nature successfully invents new molecules: 1) BGCs for complex molecules often evolve through the successive merger of smaller sub-clusters, which function as independent evolutionary entities. 2) An important subset of polyketide synthases and nonribosomal peptide synthetases evolve by concerted evolution, which generates sets of sequence-homogenized domains that may hold promise for engineering efforts since they exhibit a high degree of functional interoperability, 3) Individual BGC families evolve in distinct ways, suggesting that design strategies should take into account family-specific functional constraints. These findings suggest novel strategies for using synthetic biology to rationally engineer biosynthetic pathways. Bacterial secondary metabolites mediate a broad range of microbe-microbe and microbe-host interactions, and are widely used in human medicine, agriculture and manufacturing. Despite recent advances in synthetic biology, efforts to engineer their biosynthetic genes for the production of unnatural variants are frustrated by a high failure rate. In an effort to better understand what types of genetic changes are most likely to lead to successful improvements, we systematically analyzed the ways in which biosynthetic genes naturally evolve to generate new compounds. We show that large gene clusters appear to evolve through the merger of sub-clusters, which function independently, and are promising units for cluster engineering. Moreover, a subset of gene clusters evolve by concerted evolution, which generates sets of interoperable domains that may enable predictable domain swapping. Finally, many biosynthetic gene clusters evolve in family-specific modes that differ greatly from each other. Overall, this quantitative perspective on the ways in which gene clusters naturally evolve suggests novel strategies for using synthetic biology to engineer the production of unnatural metabolites.
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Affiliation(s)
- Marnix H. Medema
- Department of Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
- Groningen Bioinformatics Centre, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Peter Cimermancic
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, United States of America
- California Institute for Quantitative Biosciences, San Francisco, California, United States of America
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, United States of America
- California Institute for Quantitative Biosciences, San Francisco, California, United States of America
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, United States of America
| | - Eriko Takano
- Manchester Institute of Biotechnology, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Michael A. Fischbach
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, United States of America
- California Institute for Quantitative Biosciences, San Francisco, California, United States of America
- * E-mail:
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Lytic activity by temperate phages of Pseudomonas aeruginosa in long-term cystic fibrosis chronic lung infections. ISME JOURNAL 2014; 9:1391-8. [PMID: 25461970 PMCID: PMC4351911 DOI: 10.1038/ismej.2014.223] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 09/09/2014] [Accepted: 10/23/2014] [Indexed: 11/08/2022]
Abstract
Pseudomonas aeruginosa is the most common bacterial pathogen infecting the lungs of cystic fibrosis (CF) patients. The transmissible Liverpool epidemic strain (LES) harbours multiple inducible prophages (LESϕ2; LESϕ3; LESϕ4; LESϕ5; and LESϕ6), some of which are known to confer a competitive advantage in an in vivo rat model of chronic lung infection. We used quantitative PCR (Q-PCR) to measure the density and dynamics of all five LES phages in the sputa of 10 LES-infected CF patients over a period of 2 years. In all patients, the densities of free-LES phages were positively correlated with the densities of P. aeruginosa, and total free-phage densities consistently exceeded bacterial host densities 10–100-fold. Further, we observed a negative correlation between the phage-to-bacterium ratio and bacterial density, suggesting a role for lysis by temperate phages in regulation of the bacterial population densities. In 9/10 patients, LESϕ2 and LESϕ4 were the most abundant free phages, which reflects the differential in vitro induction properties of the phages. These data indicate that temperate phages of P. aeruginosa retain lytic activity after prolonged periods of chronic infection in the CF lung, and suggest that temperate phage lysis may contribute to regulation of P. aeruginosa density in vivo.
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Goodhead I, Darby AC. Taking the pseudo out of pseudogenes. Curr Opin Microbiol 2014; 23:102-9. [PMID: 25461580 DOI: 10.1016/j.mib.2014.11.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 11/11/2014] [Accepted: 11/12/2014] [Indexed: 12/23/2022]
Abstract
Pseudogenes are defined as fragments of once-functional genes that have been silenced by one or more nonsense, frameshift or missense mutations. Despite continuing increases in the speed of sequencing and annotating bacterial genomes, the identification and categorisation of pseudogenes remains problematic. Even when identified, pseudogenes are considered to be rare and tend to be ignored. On the contrary, pseudogenes are surprisingly prevalent and can persist for long evolutionary time periods, representing a record of once-functional genetic characteristics. Most importantly, pseudogenes provide an insight into prokaryotic evolutionary history as a record of phenotypic traits that have been lost. Focusing on the intracellular and symbiotic bacteria in which pseudogenes predominate, this review discusses the importance of identifying pseudogenes to fully understand the abilities of bacteria, and to understand prokaryotes within their evolutionary context.
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Affiliation(s)
- Ian Goodhead
- Functional and Comparative Genomics, School of Biological Sciences, University of Liverpool, Crown St., Liverpool L69 7ZB, UK
| | - Alistair C Darby
- Functional and Comparative Genomics, School of Biological Sciences, University of Liverpool, Crown St., Liverpool L69 7ZB, UK
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38
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Touchon M, Bobay LM, Rocha EPC. The chromosomal accommodation and domestication of mobile genetic elements. Curr Opin Microbiol 2014; 22:22-9. [DOI: 10.1016/j.mib.2014.09.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 09/17/2014] [Indexed: 11/17/2022]
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Nuñez PA, Romero H, Farber MD, Rocha EPC. Natural selection for operons depends on genome size. Genome Biol Evol 2014; 5:2242-54. [PMID: 24201372 PMCID: PMC3845653 DOI: 10.1093/gbe/evt174] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In prokaryotes, genome size is associated with metabolic versatility, regulatory complexity, effective population size, and horizontal transfer rates. We therefore analyzed the covariation of genome size and operon conservation to assess the evolutionary models of operon formation and maintenance. In agreement with previous results, intraoperonic pairs of essential and of highly expressed genes are more conserved. Interestingly, intraoperonic pairs of genes are also more conserved when they encode proteins at similar cell concentrations, suggesting a role of cotranscription in diminishing the cost of waste and shortfall in gene expression. Larger genomes have fewer and smaller operons that are also less conserved. Importantly, lower conservation in larger genomes was observed for all classes of operons in terms of gene expression, essentiality, and balanced protein concentration. We reached very similar conclusions in independent analyses of three major bacterial clades (α- and β-Proteobacteria and Firmicutes). Operon conservation is inversely correlated to the abundance of transcription factors in the genome when controlled for genome size. This suggests a negative association between the complexity of genetic networks and operon conservation. These results show that genome size and/or its proxies are key determinants of the intensity of natural selection for operon organization. Our data fit better the evolutionary models based on the advantage of coregulation than those based on genetic linkage or stochastic gene expression. We suggest that larger genomes with highly complex genetic networks and many transcription factors endure weaker selection for operons than smaller genomes with fewer alternative tools for genetic regulation.
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Affiliation(s)
- Pablo A Nuñez
- Instituto de Biotecnología, Instituto Nacional de Tecnología Agropecuaria (CICVyA-INTA), Buenos Aires, Argentina
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Wang GH, Niu LM, Ma GC, Xiao JH, Huang DW. Large proportion of genes in one cryptic WO prophage genome are actively and sex-specifically transcribed in a fig wasp species. BMC Genomics 2014; 15:893. [PMID: 25311369 PMCID: PMC4201733 DOI: 10.1186/1471-2164-15-893] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 10/03/2014] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Cryptic prophages are genetically defective in their induction and propagation, and are simply regarded as genetic remnants. There are several putative cryptic WO prophages in the sequenced Wolbachia genomes. Whether they are lytic is unclear and their functions are poorly understood. Only three open reading frames (ORFs) in cryptic WO prophages have been reported to be actively transcribed. RESULTS In this study, we comprehensively examined the transcription of the only cryptic WO prophage (WOSol) in a Wolbachia strain that infects a fig wasp, Ceratosolen solmsi (Agaonidae, Chalcidoidea). By analyzing the transcriptions of all the ORFs of WOSol in both sexes of C. solmsi, using qualitative and quantitative methods, we demonstrated that i) a high percentage of ORFs are actively transcribed (59%, 17/29); ii) the expression of these ORFs is highly sex-specific, with a strong male bias (three in females and 15 in males); iii) an ank (ankyrin-domain-containing) gene actively transcribed in both wasp sexes is more highly expressed in males. CONCLUSIONS A large proportion of the genes in the cryptic WO prophage WOSol are expressed, which overturns the concept that cryptic prophages are simply genetically defective. The highly sex-specific expression patterns of these genes in the host suggest that they play important roles in Wolbachia biology and its reproductive manipulation of its insect host, particularly through the males.
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Affiliation(s)
| | | | | | - Jin-Hua Xiao
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
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Sun M, Wang Y, Chen Z, Zhu X, Tian L, Sun Z. The first report of the vanC₁ gene in Enterococcus faecium isolated from a human clinical specimen. Mem Inst Oswaldo Cruz 2014; 109:712-5. [PMID: 25317698 PMCID: PMC4238761 DOI: 10.1590/0074-0276140019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 06/20/2014] [Indexed: 11/21/2022] Open
Abstract
The vanC1 gene, which is chromosomally located, confers resistance to vancomycin and
serves as a species marker for Enterococcus gallinarum. Enterococcus
faecium TJ4031 was isolated from a blood culture and harbours the
vanC1gene. Polymerase chain reaction (PCR) assays were performed to
detect vanXYc and vanTc genes. Only the
vanXYc gene was found in the E. faecium TJ4031 isolate. The
minimum inhibitory concentrations ofvancomycin and teicoplanin were 2 µg/mL and 1 µg/mL, respectively. Real-time
reversetranscription-PCR results revealed that the vanC1and vanXYc genes were not expressed.Pulsed-field gel electrophoresis and southern hybridisation results showed
that the vanC1 gene was encoded in the chromosome. E. faecalis isolated
from animals has been reportedto harbour vanC1gene. However, this study is the first to report the presence of the
vanC1gene in E. faecium of human origin. Additionally, our
research showed the vanC1gene cannot serve as a species-specific gene of E. gallinarum
and that it is able to be transferredbetween bacteria. Although the resistance marker is not expressed in the
strain, ourresults showed that E. faecium could acquire the
vanC1gene from different species.
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Affiliation(s)
- Mingyue Sun
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yue Wang
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zhongju Chen
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xuhui Zhu
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Lei Tian
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ziyong Sun
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
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Abstract
Integrated phages (prophages) are major contributors to the diversity of bacterial gene repertoires. Domestication of their components is thought to have endowed bacteria with molecular systems involved in secretion, defense, warfare, and gene transfer. However, the rates and mechanisms of domestication remain unknown. We used comparative genomics to study the evolution of prophages within the bacterial genome. We identified over 300 vertically inherited prophages within enterobacterial genomes. Some of these elements are very old and might predate the split between Escherichia coli and Salmonella enterica. The size distribution of prophage elements is bimodal, suggestive of rapid prophage inactivation followed by much slower genetic degradation. Accordingly, we observed a pervasive pattern of systematic counterselection of nonsynonymous mutations in prophage genes. Importantly, such patterns of purifying selection are observed not only on accessory regions but also in core phage genes, such as those encoding structural and lysis components. This suggests that bacterial hosts select for phage-associated functions. Several of these conserved prophages have gene repertoires compatible with described functions of adaptive prophage-derived elements such as bacteriocins, killer particles, gene transfer agents, or satellite prophages. We suggest that bacteria frequently domesticate their prophages. Most such domesticated elements end up deleted from the bacterial genome because they are replaced by analogous functions carried by new prophages. This puts the bacterial genome in a state of continuous flux of acquisition and loss of phage-derived adaptive genes.
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43
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Iranzo J, Gómez MJ, López de Saro FJ, Manrubia S. Large-scale genomic analysis suggests a neutral punctuated dynamics of transposable elements in bacterial genomes. PLoS Comput Biol 2014; 10:e1003680. [PMID: 24967627 PMCID: PMC4072520 DOI: 10.1371/journal.pcbi.1003680] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 05/08/2014] [Indexed: 11/18/2022] Open
Abstract
Insertion sequences (IS) are the simplest and most abundant form of transposable DNA found in bacterial genomes. When present in multiple copies, it is thought that they can promote genomic plasticity and genetic exchange, thus being a major force of evolutionary change. The main processes that determine IS content in genomes are, though, a matter of debate. In this work, we take advantage of the large amount of genomic data currently available and study the abundance distributions of 33 IS families in 1811 bacterial chromosomes. This allows us to test simple models of IS dynamics and estimate their key parameters by means of a maximum likelihood approach. We evaluate the roles played by duplication, lateral gene transfer, deletion and purifying selection. We find that the observed IS abundances are compatible with a neutral scenario where IS proliferation is controlled by deletions instead of purifying selection. Even if there may be some cases driven by selection, neutral behavior dominates over large evolutionary scales. According to this view, IS and hosts tend to coexist in a dynamic equilibrium state for most of the time. Our approach also allows for a detection of recent IS expansions, and supports the hypothesis that rapid expansions constitute transient events—punctuations—during which the state of coexistence of IS and host becomes perturbated. Insertion sequences (IS) are mobile genetic elements found in most prokaryotic genomes. They are able to autonomously change position and proliferate in chromosomes. The nature of the coevolutionary dynamics of IS with the genome that hosts them is a matter of debate: Do IS proliferate to the point of causing the extinction of the host? Is it possible that IS and hosts stably coexist? Can environmental perturbations cause IS expansions? What is the role of selection in controlling IS copy number? In this study, we have analysed abundance patterns of IS families to test two different evolutionary hypotheses: in the first one IS evolve neutrally, while in the second case they are affected by selection. Our results indicate that, most of the time, IS and their hosts coexist stably in a neutral scenario where the proliferation of IS through duplications and lateral gene transfer is balanced by regular deletions. Occasionally, though, this balance may be disrupted, causing temporary explosions of IS abundance.
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Affiliation(s)
- Jaime Iranzo
- Centro de Astrobiología (CAB), INTA-CSIC, Torrejón de Ardoz, Madrid, Spain
| | - Manuel J. Gómez
- Centro de Astrobiología (CAB), INTA-CSIC, Torrejón de Ardoz, Madrid, Spain
| | | | - Susanna Manrubia
- Centro de Astrobiología (CAB), INTA-CSIC, Torrejón de Ardoz, Madrid, Spain
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Madrid, Spain
- * E-mail:
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44
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Utter B, Deutsch DR, Schuch R, Winer BY, Verratti K, Bishop-Lilly K, Sozhamannan S, Fischetti VA. Beyond the chromosome: the prevalence of unique extra-chromosomal bacteriophages with integrated virulence genes in pathogenic Staphylococcus aureus. PLoS One 2014; 9:e100502. [PMID: 24963913 PMCID: PMC4070920 DOI: 10.1371/journal.pone.0100502] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 05/27/2014] [Indexed: 02/07/2023] Open
Abstract
In Staphylococcus aureus, the disease impact of chromosomally integrated prophages on virulence is well described. However, the existence of extra-chromosomal prophages, both plasmidial and episomal, remains obscure. Despite the recent explosion in bacterial and bacteriophage genomic sequencing, studies have failed to specifically focus on extra-chromosomal elements. We selectively enriched and sequenced extra-chromosomal DNA from S. aureus isolates using Roche-454 technology and uncovered evidence for the widespread distribution of multiple extra-chromosomal prophages (ExPΦs) throughout both antibiotic-sensitive and -resistant strains. We completely sequenced one such element comprised of a 43.8 kbp, circular ExPΦ (designated ФBU01) from a vancomycin-intermediate S. aureus (VISA) strain. Assembly and annotation of ФBU01 revealed a number of putative virulence determinants encoded within a bacteriophage immune evasion cluster (IEC). Our identification of several potential ExPΦs and mobile genetic elements (MGEs) also revealed numerous putative virulence factors and antibiotic resistance genes. We describe here a previously unidentified level of genetic diversity of stealth extra-chromosomal elements in S. aureus, including phages with a larger presence outside the chromosome that likely play a prominent role in pathogenesis and strain diversity driven by horizontal gene transfer (HGT).
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Affiliation(s)
- Bryan Utter
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, New York, United States of America
- * E-mail:
| | - Douglas R. Deutsch
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, New York, United States of America
| | - Raymond Schuch
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, New York, United States of America
| | - Benjamin Y. Winer
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, New York, United States of America
| | - Kathleen Verratti
- Henry M. Jackson Foundation, Bethesda, Maryland, United States of America
- Naval Medical Research Center-Frederick, Fort Detrick, Maryland, United States of America
| | - Kim Bishop-Lilly
- Henry M. Jackson Foundation, Bethesda, Maryland, United States of America
- Naval Medical Research Center-Frederick, Fort Detrick, Maryland, United States of America
| | - Shanmuga Sozhamannan
- Henry M. Jackson Foundation, Bethesda, Maryland, United States of America
- Naval Medical Research Center-Frederick, Fort Detrick, Maryland, United States of America
| | - Vincent A. Fischetti
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, New York, United States of America
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45
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Fernandes GDC, Trarbach LJ, de Campos SB, Beneduzi A, Passaglia LMP. Alternative nitrogenase and pseudogenes: unique features of the Paenibacillus riograndensis nitrogen fixation system. Res Microbiol 2014; 165:571-80. [PMID: 24956360 DOI: 10.1016/j.resmic.2014.06.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/13/2014] [Accepted: 06/14/2014] [Indexed: 10/25/2022]
Abstract
Biological nitrogen fixation (BNF) is a tightly regulated process that is carried out by diazotrophic microorganisms. The regulatory mechanisms of BNF-related genes are well characterized in Gram-negative models, but they are poorly understood in Gram-positive bacteria. Paenibacillus riograndensis SBR5(T) is a Gram-positive, endospore-forming facultative aerobic diazotroph. Three clusters of BNF-related genes with dissimilar phylogenetic histories were identified in the P. riograndensis genome, and no regulatory genes were recognized. P. riograndensis nifH2 was considered inactive based on transcript and promoter analyses, whereas transcripts of nifH1 and anfH were induced upon nitrogen-limited conditions. The functionality of the alternative nitrogenase system was also validated by enzymatic activity analysis. Fragments upstream of the two active clusters seem to harbor primary functional promoter sequences, producing a constitutive expression pattern in Escherichia coli. Sequences upstream of the anf genes were not recognized by this heterologous host, indicating a very distinct promoter pattern. These results shed light upon the evolutionary history of nitrogen fixation genes in this Gram-positive bacterium and highlight the presence of novel regulatory elements that are yet to be described.
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Affiliation(s)
- Gabriela de C Fernandes
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul. Av. Bento Gonçalves, 9500, Caixa Postal 15.053, 91501-970 Porto Alegre, RS, Brazil.
| | - Laura J Trarbach
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul. Av. Bento Gonçalves, 9500, Caixa Postal 15.053, 91501-970 Porto Alegre, RS, Brazil.
| | - Samanta B de Campos
- Department of Genetics of Prokaryotes, Bielefeld University, Universitätsstraße 25, 33594 Bielefeld, Germany.
| | - Anelise Beneduzi
- Fundação Estadual de Pesquisa Agropecuária (FEPAGRO), Rua Gonçalves Dias 570, 90130-060, Porto Alegre, RS, Brazil.
| | - Luciane M P Passaglia
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul. Av. Bento Gonçalves, 9500, Caixa Postal 15.053, 91501-970 Porto Alegre, RS, Brazil.
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46
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Siguier P, Gourbeyre E, Chandler M. Bacterial insertion sequences: their genomic impact and diversity. FEMS Microbiol Rev 2014; 38:865-91. [PMID: 24499397 PMCID: PMC7190074 DOI: 10.1111/1574-6976.12067] [Citation(s) in RCA: 373] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 01/19/2014] [Accepted: 01/22/2014] [Indexed: 01/06/2023] Open
Abstract
Insertion sequences (ISs), arguably the smallest and most numerous autonomous transposable elements (TEs), are important players in shaping their host genomes. This review focuses on prokaryotic ISs. We discuss IS distribution and impact on genome evolution. We also examine their effects on gene expression, especially their role in activating neighbouring genes, a phenomenon of particular importance in the recent upsurge of bacterial antibiotic resistance. We explain how ISs are identified and classified into families by a combination of characteristics including their transposases (Tpases), their overall genetic organisation and the accessory genes which some ISs carry. We then describe the organisation of autonomous and nonautonomous IS‐related elements. This is used to illustrate the growing recognition that the boundaries between different types of mobile element are becoming increasingly difficult to define as more are being identified. We review the known Tpase types, their different catalytic activities used in cleaving and rejoining DNA strands during transposition, their organisation into functional domains and the role of this in regulation. Finally, we consider examples of prokaryotic IS domestication. In a more speculative section, we discuss the necessity of constructing more quantitative dynamic models to fully appreciate the continuing impact of TEs on prokaryotic populations.
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Affiliation(s)
- Patricia Siguier
- Laboratoire de Microbiologie et Génétique Moléculaires, Unité Mixte de Recherche 5100, Centre National de Recherche Scientifique, Toulouse Cedex, France
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47
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Nielsen KM, Bøhn T, Townsend JP. Detecting rare gene transfer events in bacterial populations. Front Microbiol 2014; 4:415. [PMID: 24432015 PMCID: PMC3882822 DOI: 10.3389/fmicb.2013.00415] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 12/16/2013] [Indexed: 11/23/2022] Open
Abstract
Horizontal gene transfer (HGT) enables bacteria to access, share, and recombine genetic variation, resulting in genetic diversity that cannot be obtained through mutational processes alone. In most cases, the observation of evolutionary successful HGT events relies on the outcome of initially rare events that lead to novel functions in the new host, and that exhibit a positive effect on host fitness. Conversely, the large majority of HGT events occurring in bacterial populations will go undetected due to lack of replication success of transformants. Moreover, other HGT events that would be highly beneficial to new hosts can fail to ensue due to lack of physical proximity to the donor organism, lack of a suitable gene transfer mechanism, genetic compatibility, and stochasticity in tempo-spatial occurrence. Experimental attempts to detect HGT events in bacterial populations have typically focused on the transformed cells or their immediate offspring. However, rare HGT events occurring in large and structured populations are unlikely to reach relative population sizes that will allow their immediate identification; the exception being the unusually strong positive selection conferred by antibiotics. Most HGT events are not expected to alter the likelihood of host survival to such an extreme extent, and will confer only minor changes in host fitness. Due to the large population sizes of bacteria and the time scales involved, the process and outcome of HGT are often not amenable to experimental investigation. Population genetic modeling of the growth dynamics of bacteria with differing HGT rates and resulting fitness changes is therefore necessary to guide sampling design and predict realistic time frames for detection of HGT, as it occurs in laboratory or natural settings. Here we review the key population genetic parameters, consider their complexity and highlight knowledge gaps for further research.
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Affiliation(s)
- Kaare M Nielsen
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø Tromsø, Norway ; GenØk-Centre for Biosafety, The Science Park Tromsø, Norway
| | - Thomas Bøhn
- Department of Pharmacy, Faculty of Health Sciences, University of Tromsø Tromsø, Norway ; GenØk-Centre for Biosafety, The Science Park Tromsø, Norway
| | - Jeffrey P Townsend
- Department of Biostatistics, Yale University New Haven, CT, USA ; Program in Computational Biology and Bioinformatics, Yale University New Haven, CT, USA ; Program in Microbiology, Yale University New Haven, CT, USA
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48
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Castillo D, Espejo R, Middelboe M. Genomic structure of bacteriophage 6H and its distribution as prophage in Flavobacterium psychrophilum strains. FEMS Microbiol Lett 2013; 351:51-58. [PMID: 24267868 DOI: 10.1111/1574-6968.12342] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 11/16/2013] [Accepted: 11/17/2013] [Indexed: 02/02/2023] Open
Abstract
Flavobacterium psychrophilum is currently one of the most devastating fish pathogens worldwide causing considerable economic losses in salmonid aquaculture. Recently, attention has been drawn to the use of phages for controlling F. psychrophilum, and phages infecting the pathogen have been isolated. Here, we present the genome sequence of F. psychrophilum bacteriophage 6H and its distribution as prophage in F. psychrophilum isolates. The DNA sequence revealed a genome of 46 978 bp containing 63 predicted ORFs, of which 13% was assigned a putative function, including an integrase. Sequence analysis showed > 80% amino acid similarity to a specific region found in the virulent F. psychrophilum strain JIP02/86 (ATCC 49511), suggesting that a prophage similar to phage 6H was present in this strain. Screening for a collection of 49 F. psychrophilum strains isolated in Chile, Denmark, and USA for the presence of four phage 6H genes (integrase, tail tape protein and two hypothetical proteins) by PCR showed the presence of these prophage genes in 80% of the isolates. In conclusion, we hypothesize that bacteriophage 6H belongs to an abundant group of temperate phages which has lysogenized a large fraction of the global F. psychrophilum community.
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Affiliation(s)
- Daniel Castillo
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark; Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Macul, Santiago, Chile
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49
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Peng X, Xu H, Jones B, Chen S, Zhou H. Silicified virus-like nanoparticles in an extreme thermal environment: implications for the preservation of viruses in the geological record. GEOBIOLOGY 2013; 11:511-526. [PMID: 24102946 DOI: 10.1111/gbi.12052] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 07/20/2013] [Indexed: 06/02/2023]
Abstract
Biofilms that grow around Gumingquan hot spring (T = 71 °C, pH = 9.2) in the Rehai geothermal area, Tengchong, China, are formed of various cyanobacteria, Firmicutes, Aquificae, Thermodesulfobacteria, Desulfurococcales, and Thermoproteales. Silicified virus-like nanoparticles, 40-200 nm in diameter, are common inside the microbial cells and the extracellular polymeric substances around the cells. These nanoparticles, which are formed of a core encased by a silica cortex, are morphologically akin to known viruses and directly comparable to silicified virus-like particles that were produced in biofilms cultured in the laboratory. The information obtained from examination of the natural and laboratory-produced samples suggests that viruses can be preserved by silicification, especially while they are still encased in their host cells. These results expand our views of virus-host mineral interaction in extreme thermal environments and imply that viruses can be potentially preserved and identified in the geological record.
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Affiliation(s)
- X Peng
- State Key Laboratory of Marine Geology, Tongji University, Shanghai, China; Sanya Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China
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50
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Moura TMD, Cassenego APV, Campos FS, Ribeiro AML, Franco AC, d'Azevedo PA, Frazzon J, Frazzon APG. Detection of vanC1 gene transcription in vancomycin-susceptible Enterococcus faecalis. Mem Inst Oswaldo Cruz 2013; 108:453-6. [PMID: 23828012 PMCID: PMC3970631 DOI: 10.1590/s0074-0276108042013009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 04/02/2013] [Indexed: 11/22/2022] Open
Abstract
Here we report the presence and expression levels of the vanC1 and vanC(2/3) genes in vancomycin-susceptible strains of Enterococcus faecalis. The vanC1 and vanC(2/3) genes were located in the plasmid DNA and on the chromosome, respectively. Specific mRNA of the vanC1 gene was detected in one of these strains. Additionally, analysis of the vanC gene sequences showed that these genes are related to the vanC genes of Enterococcus gallinarum and Enterococcus casseliflavus. The presence of vanC genes is useful for the identification of E. gallinarum and E. casseliflavus. Moreover, this is the first report of vanC mRNA in E. faecalis.
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Affiliation(s)
- Tiane Martin de Moura
- Programa de Pós-Graduação em Microbiologia Agrícola e do Ambiente, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil.
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