151
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Durão P, Balbontín R, Gordo I. Evolutionary Mechanisms Shaping the Maintenance of Antibiotic Resistance. Trends Microbiol 2018; 26:677-691. [DOI: 10.1016/j.tim.2018.01.005] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/05/2018] [Accepted: 01/24/2018] [Indexed: 01/10/2023]
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152
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Evolution of Plasmid-Mediated Antibiotic Resistance in the Clinical Context. Trends Microbiol 2018; 26:978-985. [PMID: 30049587 DOI: 10.1016/j.tim.2018.06.007] [Citation(s) in RCA: 228] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 06/11/2018] [Accepted: 06/27/2018] [Indexed: 12/29/2022]
Abstract
Antibiotic-resistant infections are an urgent problem in clinical settings because they sharply increase mortality risk in critically ill patients. The horizontal spread of antibiotic resistance genes among bacteria is driven by bacterial plasmids, promoting the evolution of resistance. Crucially, particular associations exist between resistance plasmids and bacterial clones that become especially successful in clinical settings. However, the factors underlying the success of these associations remain unknown. Recent in vitro evidence reveals (i) that plasmids produce fitness costs in bacteria, and (ii) that these costs are alleviated over time through compensatory mutations. I argue that plasmid-imposed costs and subsequent compensatory adaptation may determine the success of associations between plasmids and bacteria in clinical settings, shaping the in vivo evolution of antibiotic resistance.
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153
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Abstract
Any two lineages, no matter how distant they are now, began their divergence as one population splitting into two lineages that could coexist indefinitely. The rate of origin of higher-level taxa is therefore the product of the rate of speciation times the probability that two new species coexist long enough to reach a particular level of divergence. Here I have explored these two parameters of disparification in bacteria. Owing to low recombination rates, sexual isolation is not a necessary milestone of bacterial speciation. Rather, irreversible and indefinite divergence begins with ecological diversification, that is, transmission of a bacterial lineage to a new ecological niche, possibly to a new microhabitat but at least to new resources. Several algorithms use sequence data from a taxon of focus to identify phylogenetic groups likely to bear the dynamic properties of species. Identifying these newly divergent lineages allows us to characterize the genetic bases of speciation, as well as the ecological dimensions upon which new species diverge. Speciation appears to be least frequent when a given lineage has few new resources it can adopt, as exemplified by photoautotrophs, C1 heterotrophs, and obligately intracellular pathogens; speciation is likely most rapid for generalist heterotrophs. The genetic basis of ecological divergence may determine whether ecological divergence is irreversible and whether lineages will diverge indefinitely into the future. Long-term coexistence is most likely when newly divergent lineages utilize at least some resources not shared with the other and when the resources themselves will coexist into the remote future.
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154
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Vasileva D, Suzuki-Minakuchi C, Kosono S, Yoshida M, Okada K, Nojiri H. Proteome and acylome analyses of the functional interaction network between the carbazole-degradative plasmid pCAR1 and host Pseudomonas putida KT2440. ENVIRONMENTAL MICROBIOLOGY REPORTS 2018; 10:299-309. [PMID: 29573367 DOI: 10.1111/1758-2229.12639] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 03/08/2018] [Accepted: 03/10/2018] [Indexed: 06/08/2023]
Abstract
Understanding the interplay between a plasmid and its host system is a bottleneck towards prediction of the fate of plasmid-harbouring strains in the natural environments. Here, we studied the impact of the conjugative plasmid pCAR1, involved in carbazole degradation, on the proteome of Pseudomonas putida KT2440 using SILAC method. Furthermore, we investigated two acyl lysine modifications (acetylation and succinylation) that respond to the metabolic status of the cell and are implicated in regulation of various cellular processes. The total proteome analysis revealed that the abundance of key proteins involved in metabolism, signal transduction and motility was affected by pCAR1 carriage. In total, we identified 1359 unique acetylation sites on 637 proteins and 567 unique succinylation sites on 259 proteins. Changes in the acylation status of proteins involved in metabolism and translation by pCAR1 carriage were detected. Remarkably, acylation was identified on proteins involved in important plasmid functions, including partitioning and carbazole degradation, and on nucleoid-associated proteins that play a key role in the functional interaction with the chromosome. This study provides a novel insight on the functional consequences of plasmid carriage and improves our understanding of the plasmid-host cross-talk.
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Affiliation(s)
- Delyana Vasileva
- Biotechnology Research Center, The University of Tokyo, Tokyo, Japan
| | | | - Saori Kosono
- Biotechnology Research Center, The University of Tokyo, Tokyo, Japan
- RIKEN Center for Sustainable Resource Science Wako, Saitama, Japan
| | - Minoru Yoshida
- RIKEN Center for Sustainable Resource Science Wako, Saitama, Japan
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Kazunori Okada
- Biotechnology Research Center, The University of Tokyo, Tokyo, Japan
| | - Hideaki Nojiri
- Biotechnology Research Center, The University of Tokyo, Tokyo, Japan
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155
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Hendrickson HL, Barbeau D, Ceschin R, Lawrence JG. Chromosome architecture constrains horizontal gene transfer in bacteria. PLoS Genet 2018; 14:e1007421. [PMID: 29813058 PMCID: PMC5993296 DOI: 10.1371/journal.pgen.1007421] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 06/08/2018] [Accepted: 05/16/2018] [Indexed: 11/19/2022] Open
Abstract
Despite significant frequencies of lateral gene transfer between species, higher taxonomic groups of bacteria show ecological and phenotypic cohesion. This suggests that barriers prevent panmictic dissemination of genes via lateral gene transfer. We have proposed that most bacterial genomes have a functional architecture imposed by Architecture IMparting Sequences (AIMS). AIMS are defined as 8 base pair sequences preferentially abundant on leading strands, whose abundance and strand-bias are positively correlated with proximity to the replication terminus. We determined that inversions whose endpoints lie within a single chromosome arm, which would reverse the polarity of AIMS in the inverted region, are both shorter and less frequent near the replication terminus. This distribution is consistent with the increased selection on AIMS function in this region, thus constraining DNA rearrangement. To test the hypothesis that AIMS also constrain DNA transfer between genomes, AIMS were identified in genomes while ignoring atypical, potentially laterally-transferred genes. The strand-bias of AIMS within recently acquired genes was negatively correlated with the distance of those genes from their genome’s replication terminus. This suggests that selection for AIMS function prevents the acquisition of genes whose AIMS are not found predominantly in the permissive orientation. This constraint has led to the loss of at least 18% of genes acquired by transfer in the terminus-proximal region. We used completely sequenced genomes to produce a predictive road map of paths of expected horizontal gene transfer between species based on AIMS compatibility between donor and recipient genomes. These results support a model whereby organisms retain introgressed genes only if the benefits conferred by their encoded functions outweigh the detriments incurred by the presence of foreign DNA lacking genome-wide architectural information. The potential success of horizontal gene transfer events is historically equated to the benefits conferred by encoded products. Here we show that gene transfer events are observed less frequently if the introduced genes disrupt important patterns of genomic information, suggesting that this disruption would confer an unacceptable cost. As a result, gene transfer events are less likely to be successful if the potential donor genomes have incompatible genome architecture. Because more distantly-related genes are less compatible, chromosome architecture serves as a mechanism to bias gene transfer events to those involving closer relatives, thereby providing a mechanism for the genotypic and phenotypic cohesion of higher taxonomic groups.
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Affiliation(s)
- Heather L. Hendrickson
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Institute of Natural and Mathematical Sciences, Massey University, Auckland, New Zealand
| | - Dominique Barbeau
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Robin Ceschin
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Jeffrey G. Lawrence
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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156
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Liakopoulos A, van der Goot J, Bossers A, Betts J, Brouwer MSM, Kant A, Smith H, Ceccarelli D, Mevius D. Genomic and functional characterisation of IncX3 plasmids encoding bla SHV-12 in Escherichia coli from human and animal origin. Sci Rep 2018; 8:7674. [PMID: 29769695 PMCID: PMC5955891 DOI: 10.1038/s41598-018-26073-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 05/03/2018] [Indexed: 01/09/2023] Open
Abstract
The blaSHV-12 β-lactamase gene is one of the most prevalent genes conferring resistance to extended-spectrum β-lactams in Enterobacteriaceae disseminating within and between reservoirs, mostly via plasmid-mediated horizontal gene transfer. Yet, studies regarding the biology of plasmids encoding blaSHV-12 are very limited. In this study, we revealed the emergence of IncX3 plasmids alongside IncI1α/γ in blaSHV-12 in animal-related Escherichia coli isolates. Four representative blaSHV-12-encoding IncX3 plasmids were selected for genome sequencing and further genetic and functional characterization. We report here the first complete sequences of IncX3 plasmids of animal origin and show that IncX3 plasmids exhibit remarkable synteny in their backbone, while the major differences lie in their blaSHV-12-flanking region. Our findings indicate that plasmids of this subgroup are conjugative and highly stable, while they exert no fitness cost on their bacterial host. These favourable features might have contributed to the emergence of IncX3 amongst SHV-12-producing E. coli in the Netherlands, highlighting the epidemic potential of these plasmids.
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Affiliation(s)
- Apostolos Liakopoulos
- Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, The Netherlands. .,Institute of Biology, University of Leiden, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.
| | - Jeanet van der Goot
- Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Alex Bossers
- Department of Infection Biology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Jonathan Betts
- Department of Bacteriology, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Michael S M Brouwer
- Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Arie Kant
- Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Hilde Smith
- Department of Infection Biology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Daniela Ceccarelli
- Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Dik Mevius
- Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, The Netherlands.,Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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157
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Li X, Tong W, Wang L, Rahman SU, Wei G, Tao S. A Novel Strategy for Detecting Recent Horizontal Gene Transfer and Its Application to Rhizobium Strains. Front Microbiol 2018; 9:973. [PMID: 29867876 PMCID: PMC5968381 DOI: 10.3389/fmicb.2018.00973] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/25/2018] [Indexed: 11/13/2022] Open
Abstract
Recent horizontal gene transfer (HGT) is crucial for enabling microbes to rapidly adapt to their novel environments without relying upon rare beneficial mutations that arise spontaneously. For several years now, computational approaches have been developed to detect HGT, but they typically lack the sensitivity and ability to detect recent HGT events. Here we introduce a novel strategy, named RecentHGT. The number of genes undergoing recent HGT between two bacterial genomes was estimated by a new algorithm derived from the expectation-maximization algorithm and is based on the theoretical sequence-similarity distribution of orthologous genes. We tested the proposed strategy by applying it to a set of 10 Rhizobium genomes, and detected several large-scale recent HGT events. We also found that our strategy was more sensitive than other available HGT detection methods. These HGT events were mainly mediated by symbiotic plasmids. Our new strategy can provide clear evidence of recent HGT events and thus it brings us closer to the goal of detecting these potentially adaptive evolution processes in rhizobia as well as pathogens.
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Affiliation(s)
- Xiangchen Li
- College of Life Sciences and State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, China.,Bioinformatics Center, Northwest A&F University, Yangling, China
| | - Wenjun Tong
- College of Life Sciences and State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, China
| | - Lina Wang
- College of Life Sciences and State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, China.,Bioinformatics Center, Northwest A&F University, Yangling, China
| | - Siddiq Ur Rahman
- College of Life Sciences and State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, China.,Bioinformatics Center, Northwest A&F University, Yangling, China
| | - Gehong Wei
- College of Life Sciences and State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, China
| | - Shiheng Tao
- College of Life Sciences and State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Yangling, China.,Bioinformatics Center, Northwest A&F University, Yangling, China
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158
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Hochberg ME, Marquet PA, Boyd R, Wagner A. Innovation: an emerging focus from cells to societies. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0414. [PMID: 29061887 DOI: 10.1098/rstb.2016.0414] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2017] [Indexed: 12/20/2022] Open
Abstract
Innovations are generally unexpected, often spectacular changes in phenotypes and ecological functions. The contributions to this theme issue are the latest conceptual, theoretical and experimental developments, addressing how ecology, environment, ontogeny and evolution are central to understanding the complexity of the processes underlying innovations. Here, we set the stage by introducing and defining key terms relating to innovation and discuss their relevance to biological, cultural and technological change. Discovering how the generation and transmission of novel biological information, environmental interactions and selective evolutionary processes contribute to innovation as an ecosystem will shed light on how the dominant features across life come to be, generalize to social, cultural and technological evolution, and have applications in the health sciences and sustainability.This article is part of the theme issue 'Process and pattern in innovations from cells to societies'.
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Affiliation(s)
- Michael E Hochberg
- Institut des Sciences de l'Evolution, Université de Montpellier, 34095 Montpellier, France .,Santa Fe Institute, Santa Fe, NM 87501, USA.,Institute for Advanced Study in Toulouse, 31015 Toulouse, France
| | - Pablo A Marquet
- Santa Fe Institute, Santa Fe, NM 87501, USA.,Departamento de Ecologı́a, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.,Instituto de Ecología y Biodiversidad (IEB), Casilla 653, Santiago, Chile.,Instituto de Sistemas Complejos de Valparaíso (ISCV), Artillería 4780, Valparaíso, Chile
| | - Robert Boyd
- Santa Fe Institute, Santa Fe, NM 87501, USA.,School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287, USA
| | - Andreas Wagner
- Santa Fe Institute, Santa Fe, NM 87501, USA.,Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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159
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Hall JPJ, Brockhurst MA, Harrison E. Sampling the mobile gene pool: innovation via horizontal gene transfer in bacteria. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0424. [PMID: 29061896 DOI: 10.1098/rstb.2016.0424] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2017] [Indexed: 12/26/2022] Open
Abstract
In biological systems, evolutionary innovations can spread not only from parent to offspring (i.e. vertical transmission), but also 'horizontally' between individuals, who may or may not be related. Nowhere is this more apparent than in bacteria, where novel ecological traits can spread rapidly within and between species through horizontal gene transfer (HGT). This important evolutionary process is predominantly a by-product of the infectious spread of mobile genetic elements (MGEs). We will discuss the ecological conditions that favour the spread of traits by HGT, the evolutionary and social consequences of sharing traits, and how HGT is shaped by inherent conflicts between bacteria and MGEs.This article is part of the themed issue 'Process and pattern in innovations from cells to societies'.
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Affiliation(s)
- James P J Hall
- Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Michael A Brockhurst
- Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Ellie Harrison
- P3 Institute, Department of Animal and Plant Sciences, Arthur Willis Environment Centre, University of Sheffield, 1 Maxfield Avenue, Sheffield S10 1AE, UK
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160
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Lo WS, Kuo CH. Horizontal Acquisition and Transcriptional Integration of Novel Genes in Mosquito-Associated Spiroplasma. Genome Biol Evol 2018; 9:3246-3259. [PMID: 29177479 PMCID: PMC5726471 DOI: 10.1093/gbe/evx244] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2017] [Indexed: 12/20/2022] Open
Abstract
Genetic differentiation among symbiotic bacteria is important in shaping biodiversity. The genus Spiroplasma contains species occupying diverse niches and is a model system for symbiont evolution. Previous studies have established that two mosquito-associated species have diverged extensively in their carbohydrate metabolism genes despite having a close phylogenetic relationship. Notably, although the commensal Spiroplasma diminutum lacks identifiable pathogenicity factors, the pathogenic Spiroplasma taiwanense was found to have acquired a virulence factor glpO and its associated genes through horizontal transfer. However, it is unclear if these acquired genes have been integrated into the regulatory network. In this study, we inferred the gene content evolution in these bacteria, as well as examined their transcriptomes in response to glucose availability. The results indicated that both species have many more gene acquisitions from the Mycoides-Entomoplasmataceae clade, which contains several important pathogens of ruminants, than previously thought. Moreover, several acquired genes have higher expression levels than the vertically inherited homologs, indicating possible functional replacement. Finally, the virulence factor and its functionally linked genes in S. taiwanense were up-regulated in response to glucose starvation, suggesting that these acquired genes are under expression regulation and the pathogenicity may be a stress response. In summary, although differential gene losses are a major process for symbiont divergence, gene gains are critical in counteracting genome degradation and driving diversification among facultative symbionts.
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Affiliation(s)
- Wen-Sui Lo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.,Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan.,Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.,Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan.,Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
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161
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Inter-replicon Gene Flow Contributes to Transcriptional Integration in the Sinorhizobium meliloti Multipartite Genome. G3-GENES GENOMES GENETICS 2018; 8:1711-1720. [PMID: 29563186 PMCID: PMC5940162 DOI: 10.1534/g3.117.300405] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Integration of newly acquired genes into existing regulatory networks is necessary for successful horizontal gene transfer (HGT). Ten percent of bacterial species contain at least two DNA replicons over 300 kilobases in size, with the secondary replicons derived predominately through HGT. The Sinorhizobium meliloti genome is split between a 3.7 Mb chromosome, a 1.7 Mb chromid consisting largely of genes acquired through ancient HGT, and a 1.4 Mb megaplasmid consisting primarily of recently acquired genes. Here, RNA-sequencing is used to examine the transcriptional consequences of massive, synthetic genome reduction produced through the removal of the megaplasmid and/or the chromid. Removal of the pSymA megaplasmid influenced the transcription of only six genes. In contrast, removal of the chromid influenced expression of ∼8% of chromosomal genes and ∼4% of megaplasmid genes. This was mediated in part by the loss of the ETR DNA region whose presence on pSymB is due to a translocation from the chromosome. No obvious functional bias among the up-regulated genes was detected, although genes with putative homologs on the chromid were enriched. Down-regulated genes were enriched in motility and sensory transduction pathways. Four transcripts were examined further, and in each case the transcriptional change could be traced to loss of specific pSymB regions. In particularly, a chromosomal transporter was induced due to deletion of bdhA likely mediated through 3-hydroxybutyrate accumulation. These data provide new insights into the evolution of the multipartite bacterial genome, and more generally into the integration of horizontally acquired genes into the transcriptome.
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162
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Abstract
Plasmids mediate the horizontal transmission of genetic information between bacteria, facilitating their adaptation to multiple environmental conditions. An especially important example of the ability of plasmids to catalyze bacterial adaptation and evolution is their instrumental role in the global spread of antibiotic resistance, which constitutes a major threat to public health. Plasmids provide bacteria with new adaptive tools, but they also entail a metabolic burden that, in the absence of selection for plasmid-encoded traits, reduces the competitiveness of the plasmid-carrying clone. Although this fitness reduction can be alleviated over time through compensatory evolution, the initial cost associated with plasmid carriage is the main constraint on the vertical and horizontal replication of these genetic elements. The fitness effects of plasmids therefore have a crucial influence on their ability to associate with new bacterial hosts and consequently on the evolution of plasmid-mediated antibiotic resistance. However, the molecular mechanisms underlying plasmid fitness cost remain poorly understood. Here, we analyze the literature in the field and examine the potential fitness effects produced by plasmids throughout their life cycle in the host bacterium. We also explore the various mechanisms evolved by plasmids and bacteria to minimize the cost entailed by these mobile genetic elements. Finally, we discuss potential future research directions in the field.
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163
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Chu HY, Sprouffske K, Wagner A. Assessing the benefits of horizontal gene transfer by laboratory evolution and genome sequencing. BMC Evol Biol 2018; 18:54. [PMID: 29673327 PMCID: PMC5909237 DOI: 10.1186/s12862-018-1164-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 03/22/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Recombination is widespread across the tree of life, because it helps purge deleterious mutations and creates novel adaptive traits. In prokaryotes, it often takes the form of horizontal gene transfer from a donor to a recipient bacterium. While such transfer is widespread in natural communities, its immediate fitness benefits are usually unknown. We asked whether any such benefits depend on the environment, and on the identity of donor and recipient strains. To this end, we adapted Escherichia coli to two novel carbon sources over several hundred generations of laboratory evolution, exposing evolving populations to various DNA donors. RESULTS At the end of these experiments, we measured fitness and sequenced the genomes of 65 clones from 34 replicate populations to study the genetic changes associated with adaptive evolution. Furthermore, we identified candidate de novo beneficial mutations. During adaptive evolution on the first carbon source, 4-Hydroxyphenylacetic acid (HPA), recombining populations adapted better, which was likely mediated by acquiring the hpa operon from the donor. In contrast, recombining populations did not adapt better to the second carbon source, butyric acid, even though they suffered fewer extinctions than non-recombining populations. The amount of DNA transferred, but not its benefit, strongly depended on the donor-recipient strain combination. CONCLUSIONS To our knowledge, our study is the first to investigate the genomic consequences of prokaryotic recombination and horizontal gene transfer during laboratory evolution. It shows that the benefits of recombination strongly depend on the environment and the foreign DNA donor.
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Affiliation(s)
- Hoi Yee Chu
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Kathleen Sprouffske
- The Swiss Institute of Bioinformatics, Quartier Sorge – Batiment Genopode, 1015 Lausanne, Switzerland
| | - Andreas Wagner
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- The Swiss Institute of Bioinformatics, Quartier Sorge – Batiment Genopode, 1015 Lausanne, Switzerland
- Santa Fe Institute, Santa Fe, New Mexico USA
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164
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Garbisu C, Garaiyurrebaso O, Lanzén A, Álvarez-Rodríguez I, Arana L, Blanco F, Smalla K, Grohmann E, Alkorta I. Mobile genetic elements and antibiotic resistance in mine soil amended with organic wastes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 621:725-733. [PMID: 29207350 DOI: 10.1016/j.scitotenv.2017.11.221] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 11/19/2017] [Accepted: 11/19/2017] [Indexed: 06/07/2023]
Abstract
Metal resistance has been associated with antibiotic resistance due to co- or cross-resistance mechanisms. Here, metal contaminated mine soil treated with organic wastes was screened for the presence of mobile genetic elements (MGEs). The occurrence of conjugative IncP-1 and mobilizable IncQ plasmids, as well as of class 1 integrons, was confirmed by PCR and Southern blot hybridization, suggesting that bacteria from these soils have gene-mobilizing capacity with implications for the dissemination of resistance factors. Moreover, exogenous isolation of MGEs from the soil bacterial community was attempted under antibiotic selection pressure by using Escherichia coli as recipient. Seventeen putative transconjugants were identified based on increased antibiotic resistance. Metabolic traits and metal resistance of putative transconjugants were investigated, and whole genome sequencing was carried out for two of them. Most putative transconjugants displayed a multi-resistant phenotype for a broad spectrum of antibiotics. They also displayed changes regarding the ability to metabolise different carbon sources, RNA: DNA ratio, growth rate and biofilm formation. Genome sequencing of putative transconjugants failed to detect genes acquired by horizontal gene transfer, but instead revealed a number of nonsense mutations, including in ubiH, whose inactivation was linked to the observed resistance to aminoglycosides. Our results confirm that mine soils contain MGEs encoding antibiotic resistance. Moreover, they point out the role of spontaneous mutations in achieving low-level antibiotic resistance in a short time, which was associated with a trade-off in the capability to metabolise specific carbon sources.
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Affiliation(s)
- Carlos Garbisu
- NEIKER-Tecnalia, Department of Conservation of Natural Resources, Soil Microbial Ecology Group, Berreaga 1, 48160 Derio, Spain
| | - Olatz Garaiyurrebaso
- Instituto BIOFISIKA (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, P.O. Box 644, 48080 Bilbao, Spain
| | - Anders Lanzén
- NEIKER-Tecnalia, Department of Conservation of Natural Resources, Soil Microbial Ecology Group, Berreaga 1, 48160 Derio, Spain
| | - Itxaso Álvarez-Rodríguez
- Instituto BIOFISIKA (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, P.O. Box 644, 48080 Bilbao, Spain
| | - Lide Arana
- Instituto BIOFISIKA (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, P.O. Box 644, 48080 Bilbao, Spain
| | - Fernando Blanco
- NEIKER-Tecnalia, Department of Conservation of Natural Resources, Soil Microbial Ecology Group, Berreaga 1, 48160 Derio, Spain
| | - Kornelia Smalla
- Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11-12, 38104 Braunschweig, Germany
| | - Elisabeth Grohmann
- Beuth University of Applied Sciences, Life Sciences and Technology, Department of Microbiology, Seestraße 64, 13347 Berlin, Germany
| | - Itziar Alkorta
- Instituto BIOFISIKA (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, P.O. Box 644, 48080 Bilbao, Spain.
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165
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Dietel AK, Kaltenpoth M, Kost C. Convergent Evolution in Intracellular Elements: Plasmids as Model Endosymbionts. Trends Microbiol 2018; 26:755-768. [PMID: 29650391 DOI: 10.1016/j.tim.2018.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 03/14/2018] [Accepted: 03/21/2018] [Indexed: 11/29/2022]
Abstract
Endosymbionts are organisms that live inside the cells of other species. This lifestyle is ubiquitous across the tree of life and is featured by unicellular eukaryotes, prokaryotes, and by extrachromosomal genetic elements such as plasmids. Given that all of these elements dwell in the cytoplasm of their host cell, they should be subject to similar selection pressures. Here we show that strikingly similar features have evolved in both bacterial endosymbionts and plasmids. Since host and endosymbiont are often metabolically tightly intertwined, they are difficult to disentangle experimentally. We propose that using plasmids as tractable model systems can help to solve this problem, thus allowing fundamental questions to be experimentally addressed about the ecology and evolution of endosymbiotic interactions.
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Affiliation(s)
- Anne-Kathrin Dietel
- Experimental Ecology and Evolution Research Group, Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
| | - Martin Kaltenpoth
- Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg-University, 55128 Mainz, Germany
| | - Christian Kost
- Experimental Ecology and Evolution Research Group, Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany; Current address: Department of Ecology, School of Biology/Chemistry, University of Osnabrück, 49069 Osnabrück, Germany.
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166
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Physiological and transcriptome changes induced by Pseudomonas putida acquisition of an integrative and conjugative element. Sci Rep 2018; 8:5550. [PMID: 29615803 PMCID: PMC5882942 DOI: 10.1038/s41598-018-23858-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 03/21/2018] [Indexed: 12/27/2022] Open
Abstract
Integrative and conjugative elements (ICEs) comprise ubiquitous large mobile regions in prokaryotic chromosomes that transmit vertically to daughter cells and transfer horizontally to distantly related lineages. Their evolutionary success originates in maximized combined ICE-host fitness trade-offs, but how the ICE impacts on the host metabolism and physiology is poorly understood. Here we investigate global changes in the host genetic network and physiology of Pseudomonas putida with or without an integrated ICEclc, a model ICE widely distributed in proteobacterial genomes. Genome-wide gene expression differences were analyzed by RNA-seq using exponentially growing or stationary phase-restimulated cultures on 3-chlorobenzoate, an aromatic compound metabolizable thanks to specific ICEclc-located genes. We found that the presence of ICEclc imposes a variety of changes in global pathways such as cell cycle and amino acid metabolism, which were more numerous in stationary-restimulated than exponential phase cells. Unexpectedly, ICEclc stimulates cellular motility and leads to more rapid growth on 3-chlorobenzoate than cells carrying only the integrated clc genes. ICEclc also concomitantly activates the P. putida Pspu28-prophage, but this in itself did not provoke measurable fitness effects. ICEclc thus interferes in a number of cellular pathways, inducing both direct benefits as well as indirect costs in P. putida.
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167
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Abstract
Plasmids are extrachromosomal DNA elements that can be found throughout bacteria, as well as in other domains of life. Nonetheless, the evolutionary processes underlying the persistence of plasmids are incompletely understood. Bacterial plasmids may encode genes for traits that are sometimes beneficial to their hosts, such as antimicrobial resistance, virulence, heavy metal tolerance, and the catabolism of unique nutrient sources. In the absence of selection for these traits, however, plasmids generally impose a fitness cost on their hosts. As such, plasmid persistence presents a conundrum: models predict that costly plasmids will be lost over time or that beneficial plasmid genes will be integrated into the host genome. However, laboratory and comparative studies have shown that plasmids can persist for long periods, even in the absence of positive selection. Several hypotheses have been proposed to explain plasmid persistence, including host-plasmid co-adaptation, plasmid hitchhiking, cross-ecotype transfer, and high plasmid transfer rates, but there is no clear evidence that any one model adequately resolves the plasmid paradox.
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Affiliation(s)
- Amanda C Carroll
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada.,Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | - Alex Wong
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada.,Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
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168
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Liakopoulos A, van den Bunt G, Geurts Y, Bootsma MCJ, Toleman M, Ceccarelli D, van Pelt W, Mevius DJ. High Prevalence of Intra-Familial Co-colonization by Extended-Spectrum Cephalosporin Resistant Enterobacteriaceae in Preschool Children and Their Parents in Dutch Households. Front Microbiol 2018. [PMID: 29515562 PMCID: PMC5826366 DOI: 10.3389/fmicb.2018.00293] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Extended-spectrum cephalosporin-resistant (ESCR) Enterobacteriaceae pose a serious infection control challenge for public health. The emergence of the ESCR phenotype is mostly facilitated by plasmid-mediated horizontal extended-spectrum β-lactamases (ESBLs) and AmpC gene transfer within Enterobacteriaceae. Current data regarding the plasmid contribution to this emergence within the Dutch human population is limited. Hence, the aim of this study was to gain insight into the role of plasmids in the dissemination of ESBL/AmpC genes inside Dutch households with preschool children and precisely delineate co-colonization. In 87 ESCREnterobacteriaceae from fecal samples of parents and preschool children within 66 Dutch households, genomic localization, plasmid type and insertion sequences linked to ESBL/AmpC genes were determined. Chromosomal location of ESBL/AmpC genes was confirmed when needed. An epidemiologically relevant subset of the isolates based on household co-carriage was assessed by Multilocus Sequence Typing and Pulsed-Field Gel Electrophoresis for genetic relatedness. The narrow-host range I1α and F plasmids were the major facilitators of ESBL/AmpC-gene dissemination. Interestingly, we documented a relatively high occurrence of chromosomal integration of typically plasmid-encoded ESBL/AmpC-genes. A high diversity of non-epidemic Escherichia coli sequence types (STs) was revealed; the predominant STs belonged to the pandemic lineages of extraintestinal pathogenic E. coli ST131 and ST69. Intra-familiar co-carriage by identical ESCREnterobacteriaceae was documented in 7 households compared to 14 based on sole gene typing, as previously reported. Co-carriage was more frequent than expected based on pure chance, suggesting clonal transmission between children and parents within the household.
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Affiliation(s)
- Apostolos Liakopoulos
- Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, Netherlands
| | - Gerrita van den Bunt
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, Netherlands.,Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
| | - Yvon Geurts
- Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, Netherlands
| | - Martin C J Bootsma
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, Netherlands.,Department of Mathematics, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Mark Toleman
- Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Daniela Ceccarelli
- Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, Netherlands
| | - Wilfrid van Pelt
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
| | - Dik J Mevius
- Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Lelystad, Netherlands.,Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
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169
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Watson BNJ, Staals RHJ, Fineran PC. CRISPR-Cas-Mediated Phage Resistance Enhances Horizontal Gene Transfer by Transduction. mBio 2018; 9:e02406-17. [PMID: 29440578 PMCID: PMC5821089 DOI: 10.1128/mbio.02406-17] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 01/17/2018] [Indexed: 12/27/2022] Open
Abstract
A powerful contributor to prokaryotic evolution is horizontal gene transfer (HGT) through transformation, conjugation, and transduction, which can be advantageous, neutral, or detrimental to fitness. Bacteria and archaea control HGT and phage infection through CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins) adaptive immunity. Although the benefits of resisting phage infection are evident, this can come at a cost of inhibiting the acquisition of other beneficial genes through HGT. Despite the ability of CRISPR-Cas to limit HGT through conjugation and transformation, its role in transduction is largely overlooked. Transduction is the phage-mediated transfer of bacterial DNA between cells and arguably has the greatest impact on HGT. We demonstrate that in Pectobacterium atrosepticum, CRISPR-Cas can inhibit the transduction of plasmids and chromosomal loci. In addition, we detected phage-mediated transfer of a large plant pathogenicity genomic island and show that CRISPR-Cas can inhibit its transduction. Despite these inhibitory effects of CRISPR-Cas on transduction, its more common role in phage resistance promotes rather than diminishes HGT via transduction by protecting bacteria from phage infection. This protective effect can also increase transduction of phage-sensitive members of mixed populations. CRISPR-Cas systems themselves display evidence of HGT, but little is known about their lateral dissemination between bacteria and whether transduction can contribute. We show that, through transduction, bacteria can acquire an entire chromosomal CRISPR-Cas system, including cas genes and phage-targeting spacers. We propose that the positive effect of CRISPR-Cas phage immunity on enhancing transduction surpasses the rarer cases where gene flow by transduction is restricted.IMPORTANCE The generation of genetic diversity through acquisition of DNA is a powerful contributor to microbial evolution and occurs through transformation, conjugation, and transduction. Of these, transduction, the phage-mediated transfer of bacterial DNA, is arguably the major route for genetic exchange. CRISPR-Cas adaptive immune systems control gene transfer by conjugation and transformation, but transduction has been mostly overlooked. Our results indicate that CRISPR-Cas can impede, but typically enhances the transduction of plasmids, chromosomal genes, and pathogenicity islands. By limiting wild-type phage replication, CRISPR-Cas immunity increases transduction in both phage-resistant and -sensitive members of mixed populations. Furthermore, we demonstrate mobilization of a chromosomal CRISPR-Cas system containing phage-targeting spacers by generalized transduction, which might partly account for the uneven distribution of these systems in nature. Overall, the ability of CRISPR-Cas to promote transduction reveals an unexpected impact of adaptive immunity on horizontal gene transfer, with broader implications for microbial evolution.
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Affiliation(s)
- Bridget N J Watson
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Raymond H J Staals
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Bio-Protection Research Centre, University of Otago, Dunedin, New Zealand
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170
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Boto L. Are There Really Too Many Eukaryote LGTs? A Reply To William Martin. Bioessays 2018; 40. [DOI: 10.1002/bies.201800001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 01/10/2018] [Indexed: 11/12/2022]
Affiliation(s)
- Luis Boto
- Departamento de Biodiversidad y Biología Evolutiva, Museo Nacional de Ciencias Naturales (CSIC); C/ José Gutierrez Abascal 2 28006 Madrid Spain
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171
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Porse A, Schou TS, Munck C, Ellabaan MMH, Sommer MOA. Biochemical mechanisms determine the functional compatibility of heterologous genes. Nat Commun 2018; 9:522. [PMID: 29410400 PMCID: PMC5802803 DOI: 10.1038/s41467-018-02944-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 01/09/2018] [Indexed: 11/28/2022] Open
Abstract
Elucidating the factors governing the functional compatibility of horizontally transferred genes is important to understand bacterial evolution, including the emergence and spread of antibiotic resistance, and to successfully engineer biological systems. In silico efforts and work using single-gene libraries have suggested that sequence composition is a strong barrier for the successful integration of heterologous genes. Here we sample 200 diverse genes, representing >80% of sequenced antibiotic resistance genes, to interrogate the factors governing genetic compatibility in new hosts. In contrast to previous work, we find that GC content, codon usage, and mRNA-folding energy are of minor importance for the compatibility of mechanistically diverse gene products at moderate expression. Instead, we identify the phylogenetic origin, and the dependence of a resistance mechanism on host physiology, as major factors governing the functionality and fitness of antibiotic resistance genes. These findings emphasize the importance of biochemical mechanism for heterologous gene compatibility, and suggest physiological constraints as a pivotal feature orienting the evolution of antibiotic resistance. Sequence composition is thought to be a major factor governing the functionality of horizontally transferred genes. In contrast, Porse et al. show that phylogenetic origin, and the type of resistance mechanism, are major factors affecting the functionality of horizontally transferred antibiotic resistance genes.
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Affiliation(s)
- Andreas Porse
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, DK-2800, Denmark
| | - Thea S Schou
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, DK-2800, Denmark
| | - Christian Munck
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, DK-2800, Denmark
| | - Mostafa M H Ellabaan
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, DK-2800, Denmark
| | - Morten O A Sommer
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, DK-2800, Denmark.
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172
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Bengtsson-Palme J, Kristiansson E, Larsson DGJ. Environmental factors influencing the development and spread of antibiotic resistance. FEMS Microbiol Rev 2018; 42:4563583. [PMID: 29069382 PMCID: PMC5812547 DOI: 10.1093/femsre/fux053] [Citation(s) in RCA: 496] [Impact Index Per Article: 82.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/19/2017] [Indexed: 11/25/2022] Open
Abstract
Antibiotic resistance and its wider implications present us with a growing healthcare crisis. Recent research points to the environment as an important component for the transmission of resistant bacteria and in the emergence of resistant pathogens. However, a deeper understanding of the evolutionary and ecological processes that lead to clinical appearance of resistance genes is still lacking, as is knowledge of environmental dispersal barriers. This calls for better models of how resistance genes evolve, are mobilized, transferred and disseminated in the environment. Here, we attempt to define the ecological and evolutionary environmental factors that contribute to resistance development and transmission. Although mobilization of resistance genes likely occurs continuously, the great majority of such genetic events do not lead to the establishment of novel resistance factors in bacterial populations, unless there is a selection pressure for maintaining them or their fitness costs are negligible. To enable preventative measures it is therefore critical to investigate under what conditions and to what extent environmental selection for resistance takes place. In addition, understanding dispersal barriers is not only key to evaluate risks, but also to prevent resistant pathogens, as well as novel resistance genes, from reaching humans.
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Affiliation(s)
- Johan Bengtsson-Palme
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Box 440, SE-40530, Gothenburg, Sweden
- Department of Infectious Diseases, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Guldhedsgatan 10, SE-413 46, Gothenburg, Sweden
| | - Erik Kristiansson
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Box 440, SE-40530, Gothenburg, Sweden
- Department of Mathematical Sciences, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - D G Joakim Larsson
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Box 440, SE-40530, Gothenburg, Sweden
- Department of Infectious Diseases, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Guldhedsgatan 10, SE-413 46, Gothenburg, Sweden
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173
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Wu D, Dolfing J, Xie B. Bacterial perspectives on the dissemination of antibiotic resistance genes in domestic wastewater bio-treatment systems: beneficiary to victim. Appl Microbiol Biotechnol 2017; 102:597-604. [DOI: 10.1007/s00253-017-8665-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 11/16/2017] [Accepted: 11/17/2017] [Indexed: 11/24/2022]
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174
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Ambur OH, Engelstädter J, Johnsen PJ, Miller EL, Rozen DE. Steady at the wheel: conservative sex and the benefits of bacterial transformation. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0528. [PMID: 27619692 PMCID: PMC5031613 DOI: 10.1098/rstb.2015.0528] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2016] [Indexed: 12/25/2022] Open
Abstract
Many bacteria are highly sexual, but the reasons for their promiscuity remain obscure. Did bacterial sex evolve to maximize diversity and facilitate adaptation in a changing world, or does it instead help to retain the bacterial functions that work right now? In other words, is bacterial sex innovative or conservative? Our aim in this review is to integrate experimental, bioinformatic and theoretical studies to critically evaluate these alternatives, with a main focus on natural genetic transformation, the bacterial equivalent of eukaryotic sexual reproduction. First, we provide a general overview of several hypotheses that have been put forward to explain the evolution of transformation. Next, we synthesize a large body of evidence highlighting the numerous passive and active barriers to transformation that have evolved to protect bacteria from foreign DNA, thereby increasing the likelihood that transformation takes place among clonemates. Our critical review of the existing literature provides support for the view that bacterial transformation is maintained as a means of genomic conservation that provides direct benefits to both individual bacterial cells and to transformable bacterial populations. We examine the generality of this view across bacteria and contrast this explanation with the different evolutionary roles proposed to maintain sex in eukaryotes. This article is part of the themed issue 'Weird sex: the underappreciated diversity of sexual reproduction'.
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Affiliation(s)
- Ole Herman Ambur
- Department of Life Sciences and Health, Oslo and Akershus University College of Applied Sciences, 1478 Oslo, Norway
| | - Jan Engelstädter
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Pål J Johnsen
- Faculty of Health Sciences, Department of Pharmacy, UiT-The Arctic University of Norway, 9037 Tromsø, Norway
| | - Eric L Miller
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PL, UK
| | - Daniel E Rozen
- Institute of Biology, Leiden University, 2333 BE Leiden, The Netherlands
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175
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Ren Q, Wang C, Jin M, Lan J, Ye T, Hui K, Tan J, Wang Z, Wyckoff GJ, Wang W, Han GZ. Co-option of bacteriophage lysozyme genes by bivalve genomes. Open Biol 2017; 7:rsob.160285. [PMID: 28100665 PMCID: PMC5303276 DOI: 10.1098/rsob.160285] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 12/14/2016] [Indexed: 01/08/2023] Open
Abstract
Eukaryotes have occasionally acquired genetic material through horizontal gene transfer (HGT). However, little is known about the evolutionary and functional significance of such acquisitions. Lysozymes are ubiquitous enzymes that degrade bacterial cell walls. Here, we provide evidence that two subclasses of bivalves (Heterodonta and Palaeoheterodonta) acquired a lysozyme gene via HGT, building on earlier findings. Phylogenetic analyses place the bivalve lysozyme genes within the clade of bacteriophage lysozyme genes, indicating that the bivalves acquired the phage-type lysozyme genes from bacteriophages, either directly or through intermediate hosts. These bivalve lysozyme genes underwent dramatic structural changes after their co-option, including intron gain and fusion with other genes. Moreover, evidence suggests that recurrent gene duplication occurred in the bivalve lysozyme genes. Finally, we show the co-opted lysozymes exhibit a capacity for antibacterial action, potentially augmenting the immune function of related bivalves. This represents an intriguing evolutionary strategy in the eukaryote–microbe arms race, in which the genetic materials of bacteriophages are co-opted by eukaryotes, and then used by eukaryotes to combat bacteria, using a shared weapon against a common enemy.
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Affiliation(s)
- Qian Ren
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing 210046, People's Republic of China
| | - Chunyang Wang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing 210046, People's Republic of China.,State Key Laboratory of Crop Biology, College of Agronomy, Shandong Agricultural University, Tai'an, Shandong 271018, People's Republic of China
| | - Min Jin
- State Key Laboratory Breeding Base of Marine Genetic Resource, Third Institute of Oceanography, SOA, Xiamen 361005, People's Republic of China
| | - Jiangfeng Lan
- College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China
| | - Ting Ye
- College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, People's Republic of China
| | - Kaimin Hui
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing 210046, People's Republic of China
| | - Jingmin Tan
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing 210046, People's Republic of China
| | - Zheng Wang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing 210046, People's Republic of China
| | - Gerald J Wyckoff
- Divison of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 5100 Rockhill Rd., Kansas City, MO 64110, USA
| | - Wen Wang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing 210046, People's Republic of China
| | - Guan-Zhu Han
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing 210046, People's Republic of China
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176
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177
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Antibiotics Promote Escherichia coli-Pseudomonas aeruginosa Conjugation through Inhibiting Quorum Sensing. Antimicrob Agents Chemother 2017; 61:AAC.01284-17. [PMID: 28993333 DOI: 10.1128/aac.01284-17] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 09/30/2017] [Indexed: 12/19/2022] Open
Abstract
The effect of antibiotics on horizontal gene transfer (HGT) is controversial, and the underlying mechanism remains poorly understood. Here, using Escherichia coli SM10λπ as the donor strain, which carries a chromosomally integrated RP4 plasmid, we investigated the effect of antibiotics on conjugational transfer of a mobilizable gentamicin (Gm) resistance plasmid. The results showed that an exposure to gentamicin that restricted the survival of recipient cells significantly enhanced SM10λπ-Pseudomonas aeruginosa PAO1 conjugation, which was attenuated by a deficiency of lasI-rhlI, genes associated with the generation of the quorum sensing signals N-acyl homoserine lactones (AHLs) in PAO1, or the deletion of the AHL receptor SdiA in SM10λπ. Subsequent mechanistic investigations revealed that a treatment with Gm repressed the mRNA expression of lasI and rhlI in PAO1 and upregulated traI expression in SM10λπ. Moreover, PAO1 treated with other quorum sensing (QS)-inhibiting antibiotics such as azithromycin or chloramphenicol also showed a conjugation-promoting ability. On the other hand, when using non-AHL-producing E. coli strain EC600 as the recipient cells, the promoting effect of Gm on conjugation could not be observed. These data suggest that AHL-SdiA contributes to the effectiveness of antibiotics on plasmid conjugation. Collectively, our findings highlight the HGT-promoting effect of antibiotics and suggest quorum sensing as a promising target for controlling antibiotic resistance dissemination. These findings have implications for assessing the risks of antibiotic use and developing advisable antibiotic treatment protocols.
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178
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Michael CA, Franks AE, Labbate M. The antimicrobial resistance crisis: management through gene monitoring. Open Biol 2017; 6:rsob.160236. [PMID: 27831476 PMCID: PMC5133444 DOI: 10.1098/rsob.160236] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 10/14/2016] [Indexed: 12/13/2022] Open
Abstract
Antimicrobial resistance (AMR) is an acknowledged crisis for humanity. Its genetic origins and dire potential outcomes are increasingly well understood. However, diagnostic techniques for monitoring the crisis are currently largely limited to enumerating the increasing incidence of resistant pathogens. Being the end-stage of the evolutionary process that produces antimicrobial resistant pathogens, these measurements, while diagnostic, are not prognostic, and so are not optimal in managing this crisis. A better test is required. Here, using insights from an understanding of evolutionary processes ruling the changing abundance of genes under selective pressure, we suggest a predictive framework for the AMR crisis. We then discuss the likely progression of resistance for both existing and prospective antimicrobial therapies. Finally, we suggest that by the environmental monitoring of resistance gene frequency, resistance may be detected and tracked presumptively, and how this tool may be used to guide decision-making in the local and global use of antimicrobials.
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Affiliation(s)
- Carolyn A Michael
- School of Life Sciences, University of Technology Sydney, Sydney 2007, Australia
| | - Ashley E Franks
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Victoria, Australia
| | - Maurizio Labbate
- School of Life Sciences, University of Technology Sydney, Sydney 2007, Australia.,ithree institute, University of Technology Sydney, Sydney 2007, Australia
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179
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Garbisu C, Garaiyurrebaso O, Epelde L, Grohmann E, Alkorta I. Plasmid-Mediated Bioaugmentation for the Bioremediation of Contaminated Soils. Front Microbiol 2017; 8:1966. [PMID: 29062312 PMCID: PMC5640721 DOI: 10.3389/fmicb.2017.01966] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 09/25/2017] [Indexed: 11/29/2022] Open
Abstract
Bioaugmentation, or the inoculation of microorganisms (e.g., bacteria harboring the required catabolic genes) into soil to enhance the rate of contaminant degradation, has great potential for the bioremediation of soils contaminated with organic compounds. Regrettably, cell bioaugmentation frequently turns into an unsuccessful initiative, owing to the rapid decrease of bacterial viability and abundance after inoculation, as well as the limited dispersal of the inoculated bacteria in the soil matrix. Genes that encode the degradation of organic compounds are often located on plasmids and, consequently, they can be spread by horizontal gene transfer into well-established, ecologically competitive, indigenous bacterial populations. Plasmid-mediated bioaugmentation aims to stimulate the spread of contaminant degradation genes among indigenous soil bacteria by the introduction of plasmids, located in donor cells, harboring such genes. But the acquisition of plasmids by recipient cells can affect the host’s fitness, a crucial aspect for the success of plasmid-mediated bioaugmentation. Besides, environmental factors (e.g., soil moisture, temperature, organic matter content) can play important roles for the transfer efficiency of catabolic plasmids, the expression of horizontally acquired genes and, finally, the contaminant degradation activity. For plasmid-mediated bioaugmentation to be reproducible, much more research is needed for a better selection of donor bacterial strains and accompanying plasmids, together with an in-depth understanding of indigenous soil bacterial populations and the environmental conditions that affect plasmid acquisition and the expression and functioning of the catabolic genes of interest.
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Affiliation(s)
- Carlos Garbisu
- Soil Microbial Ecology Group, Department of Conservation of Natural Resources, Neiker Tecnalia, Derio, Spain
| | - Olatz Garaiyurrebaso
- Instituto Biofisika (UPV/EHU, CSIC), Department of Biochemistry and Molecular Biology, University of the Basque Country, Bilbao, Spain
| | - Lur Epelde
- Soil Microbial Ecology Group, Department of Conservation of Natural Resources, Neiker Tecnalia, Derio, Spain
| | | | - Itziar Alkorta
- Soil Microbial Ecology Group, Department of Conservation of Natural Resources, Neiker Tecnalia, Derio, Spain
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180
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diCenzo GC, Finan TM. The Divided Bacterial Genome: Structure, Function, and Evolution. Microbiol Mol Biol Rev 2017; 81:e00019-17. [PMID: 28794225 PMCID: PMC5584315 DOI: 10.1128/mmbr.00019-17] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Approximately 10% of bacterial genomes are split between two or more large DNA fragments, a genome architecture referred to as a multipartite genome. This multipartite organization is found in many important organisms, including plant symbionts, such as the nitrogen-fixing rhizobia, and plant, animal, and human pathogens, including the genera Brucella, Vibrio, and Burkholderia. The availability of many complete bacterial genome sequences means that we can now examine on a broad scale the characteristics of the different types of DNA molecules in a genome. Recent work has begun to shed light on the unique properties of each class of replicon, the unique functional role of chromosomal and nonchromosomal DNA molecules, and how the exploitation of novel niches may have driven the evolution of the multipartite genome. The aims of this review are to (i) outline the literature regarding bacterial genomes that are divided into multiple fragments, (ii) provide a meta-analysis of completed bacterial genomes from 1,708 species as a way of reviewing the abundant information present in these genome sequences, and (iii) provide an encompassing model to explain the evolution and function of the multipartite genome structure. This review covers, among other topics, salient genome terminology; mechanisms of multipartite genome formation; the phylogenetic distribution of multipartite genomes; how each part of a genome differs with respect to genomic signatures, genetic variability, and gene functional annotation; how each DNA molecule may interact; as well as the costs and benefits of this genome structure.
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Affiliation(s)
- George C diCenzo
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Turlough M Finan
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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181
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Gama JA, Zilhão R, Dionisio F. Conjugation efficiency depends on intra and intercellular interactions between distinct plasmids: Plasmids promote the immigration of other plasmids but repress co-colonizing plasmids. Plasmid 2017; 93:6-16. [PMID: 28842132 DOI: 10.1016/j.plasmid.2017.08.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 08/17/2017] [Accepted: 08/18/2017] [Indexed: 12/13/2022]
Abstract
Conjugative plasmids encode the genes responsible for the synthesis of conjugative pili and plasmid transfer. Expression of the conjugative machinery (including conjugative pili) may be costly to bacteria, not only due to the energetic/metabolic cost associated with their expression but also because they serve as receptors for certain viruses. Consequently, the presence of two plasmids in the same cell may be disadvantageous to each plasmid, because they may impose a higher fitness cost on the host. Therefore, plasmids may encode mechanisms to cope with co-resident plasmids. Moreover, it is possible that the transfer rate of a plasmid is affected by the presence of a distinct plasmid in the recipient cell. In this work, we measured transfer rates of twelve natural plasmids belonging to seven incompatibility groups in three situations, namely when: (i) donor cells contain a plasmid and recipient cells are plasmid-free; (ii) donor cells contain two unrelated plasmids and recipient cells are plasmid-free; and (iii) half of the cells contain a given plasmid and the other half contain another, unrelated, plasmid. In the third situation, recipient cells of a plasmid are the donor cells of the other plasmid. We show that there are more negative interactions (reduction of a plasmid's conjugative efficiency) between plasmids if they reside in the same cell than if they reside in different cells. However, if plasmids interacted intercellularly, the transfer rate of one of the plasmids was often higher (when the unrelated conjugative plasmid was present in the recipient cell) than if the recipient cell was plasmid-free - a positive effect. Experimental data retrieved from the study of mutant plasmids not expressing conjugative pili on the cell surface suggest that positive effects result from a higher efficiency of mating pair formation. Overall, our results suggest that negative interactions are significantly more frequent when plasmids occupy the same cell. Such interactions may determine how antibiotic resistance disseminates in bacterial populations.
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Affiliation(s)
- João Alves Gama
- cE3c-Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal; Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Rita Zilhão
- Departamento de Biologia Vegetal, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Francisco Dionisio
- cE3c-Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal; Instituto Gulbenkian de Ciência, Oeiras, Portugal; Departamento de Biologia Vegetal, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal.
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182
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Grinberg A, Biggs PJ, Zhang J, Ritchie S, Oneroa Z, O'Neill C, Karkaba A, Velathanthiri NS, Coombs GW. Genomic epidemiology of methicillin-susceptible Staphylococcus aureus across colonisation and skin and soft tissue infection. J Infect 2017; 75:326-335. [PMID: 28782565 DOI: 10.1016/j.jinf.2017.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 07/29/2017] [Indexed: 12/24/2022]
Abstract
OBJECTIVES Staphylococcus aureus skin and soft tissue infection (Sa-SSTI) places a significant burden on healthcare systems. New Zealand has a high incidence of Sa-SSTI, and here most morbidity is caused by a polyclonal methicillin-susceptible (MSSA) bacterial population. However, MSSA also colonise asymptomatically the cornified epithelia of approximately 20% of the population, and their divide between commensalism and pathogenicity is poorly understood. We aimed to see whether MSSA are genetically differentiated across colonisation and SSTI; and given the close interactions between people and pets, whether strains isolated from pets differ from human strains. METHODS We compared the genomes of contemporaneous colonisation and clinical MSSA isolates obtained in New Zealand from humans and pets. RESULTS Core and accessory genome comparisons revealed a homogeneous bacterial population across colonisation, disease, humans, and pets. The rate of MSSA colonisation in dogs was comparatively low (5.4%). CONCLUSIONS In New Zealand, most Sa-SSTI morbidity is caused by a random sample of the colonising MSSA population, consistent with the opportunistic infection model rather than the paradigm distinguishing strains according to their pathogenicity. Thus, studies of the factors determining colonisation and immune-escape may be more beneficial than comparative virulence studies. Contact with house-hold pets may pose low zoonotic risk.
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Affiliation(s)
- Alex Grinberg
- Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Private Bag 11,222, Palmerston North, 4442, New Zealand.
| | - Patrick J Biggs
- Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Private Bag 11,222, Palmerston North, 4442, New Zealand
| | - Ji Zhang
- Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Private Bag 11,222, Palmerston North, 4442, New Zealand
| | - Stephen Ritchie
- University of Auckland, Faculty of Medical and Health Sciences, Molecular Medicine and Pathology, 85 Park Rd, Grafton, Auckland, 1023, New Zealand
| | - Zachary Oneroa
- Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Private Bag 11,222, Palmerston North, 4442, New Zealand
| | - Charlotte O'Neill
- Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Private Bag 11,222, Palmerston North, 4442, New Zealand
| | - Ali Karkaba
- Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Private Bag 11,222, Palmerston North, 4442, New Zealand
| | - Niluka S Velathanthiri
- Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Private Bag 11,222, Palmerston North, 4442, New Zealand
| | - Geoffrey W Coombs
- School of Veterinary and Life Sciences, Murdoch University, 90 South Street, Murdoch, WA, Australia
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183
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Hall JPJ, Williams D, Paterson S, Harrison E, Brockhurst MA. Positive selection inhibits gene mobilisation and transfer in soil bacterial communities. Nat Ecol Evol 2017; 1:1348-1353. [PMID: 28890938 PMCID: PMC5584672 DOI: 10.1038/s41559-017-0250-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- James P J Hall
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK. .,Department of Biology, University of York, York, YO10 5DD, UK.
| | - David Williams
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Liverpool, L69 7ZB, UK
| | - Steve Paterson
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Liverpool, L69 7ZB, UK
| | - Ellie Harrison
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Michael A Brockhurst
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
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184
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Abstract
Bacteria gain antibiotic resistance genes by horizontal acquisition of mobile genetic elements (MGE) from other lineages. Newly acquired MGEs are often poorly adapted causing intragenomic conflicts, resolved by compensatory adaptation of the chromosome, the MGE or reciprocal coadaptation. The footprints of such intragenomic coevolution are present in bacterial genomes, suggesting an important role promoting genomic integration of horizontally acquired genes, but direct experimental evidence of the process is limited. Here we show adaptive modulation of tetracycline resistance via intragenomic coevolution between Escherichia coli and the multi-drug resistant (MDR) plasmid RK2. Tetracycline treatments, including monotherapy or combination therapies with ampicillin, favoured de novo chromosomal resistance mutations coupled with mutations on RK2 impairing the plasmid-encoded tetracycline efflux-pump. These mutations together provided increased tetracycline resistance at reduced cost. Additionally, the chromosomal resistance mutations conferred cross-resistance to chloramphenicol. Reciprocal coadaptation was not observed under ampicillin-only or no antibiotic selection. Intragenomic coevolution can create genomes comprised of multiple replicons that together provide high-level, low-cost resistance, but the resulting co-dependence may limit the spread of coadapted MGEs to other lineages.
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185
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Chu HY, Sprouffske K, Wagner A. The role of recombination in evolutionary adaptation of Escherichia coli to a novel nutrient. J Evol Biol 2017; 30:1692-1711. [PMID: 28612351 DOI: 10.1111/jeb.13132] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/11/2017] [Accepted: 06/05/2017] [Indexed: 12/11/2022]
Abstract
The benefits and detriments of recombination for adaptive evolution have been studied both theoretically and experimentally, with conflicting predictions and observations. Most pertinent experiments examine recombination's effects in an unchanging environment and do not study its genomewide effects. Here, we evolved six replicate populations of either highly recombining R+ or lowly recombining R- E. coli strains in a changing environment, by introducing the novel nutrients L-arabinose or indole into the environment. The experiment's ancestral strains are not viable on these nutrients, but 130 generations of adaptive evolution were sufficient to render them viable. Recombination conferred a more pronounced advantage to populations adapting to indole. To study the genomic changes associated with this advantage, we sequenced the genomes of 384 clones isolated from selected replicates at the end of the experiment. These genomes harbour complex changes that range from point mutations to large-scale DNA amplifications. Among several candidate adaptive mutations, those in the tryptophanase regulator tnaC stand out, because the tna operon in which it resides has a known role in indole metabolism. One of the highly recombining populations also shows a significant excess of large-scale segmental DNA amplifications that include the tna operon. This lineage also shows a unique and potentially adaptive combination of point mutations and DNA amplifications that may have originated independently from one another, to be joined later by recombination. Our data illustrate that the advantages of recombination for adaptive evolution strongly depend on the environment and that they can be associated with complex genomic changes.
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Affiliation(s)
- H-Y Chu
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - K Sprouffske
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - A Wagner
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,The Swiss Institute of Bioinformatics, Quartier Sorge, Batiment Genopode, Lausanne, Switzerland.,The Santa Fe Institute, Santa Fe, NM, USA
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186
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Delavat F, Miyazaki R, Carraro N, Pradervand N, van der Meer JR. The hidden life of integrative and conjugative elements. FEMS Microbiol Rev 2017; 41:512-537. [PMID: 28369623 PMCID: PMC5812530 DOI: 10.1093/femsre/fux008] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 02/20/2017] [Indexed: 01/01/2023] Open
Abstract
Integrative and conjugative elements (ICEs) are widespread mobile DNA that transmit both vertically, in a host-integrated state, and horizontally, through excision and transfer to new recipients. Different families of ICEs have been discovered with more or less restricted host ranges, which operate by similar mechanisms but differ in regulatory networks, evolutionary origin and the types of variable genes they contribute to the host. Based on reviewing recent experimental data, we propose a general model of ICE life style that explains the transition between vertical and horizontal transmission as a result of a bistable decision in the ICE-host partnership. In the large majority of cells, the ICE remains silent and integrated, but hidden at low to very low frequencies in the population specialized host cells appear in which the ICE starts its process of horizontal transmission. This bistable process leads to host cell differentiation, ICE excision and transfer, when suitable recipients are present. The ratio of ICE bistability (i.e. ratio of horizontal to vertical transmission) is the outcome of a balance between fitness costs imposed by the ICE horizontal transmission process on the host cell, and selection for ICE distribution (i.e. ICE 'fitness'). From this emerges a picture of ICEs as elements that have adapted to a mostly confined life style within their host, but with a very effective and dynamic transfer from a subpopulation of dedicated cells.
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Affiliation(s)
- François Delavat
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne Switzerland
| | - Ryo Miyazaki
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8566, Japan
| | - Nicolas Carraro
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne Switzerland
| | - Nicolas Pradervand
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne Switzerland
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187
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Klahn P, Brönstrup M. Bifunctional antimicrobial conjugates and hybrid antimicrobials. Nat Prod Rep 2017; 34:832-885. [PMID: 28530279 DOI: 10.1039/c7np00006e] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Covering: up to the end of 2016Novel antimicrobial drugs are continuously needed to counteract bacterial resistance development. An innovative molecular design strategy for novel antibiotic drugs is based on the hybridization of an antibiotic with a second functional entity. Such conjugates can be grouped into two major categories. In the first category (antimicrobial hybrids), both functional elements of the hybrid exert antimicrobial activity. Due to the dual targeting, resistance development can be significantly impaired, the pharmacokinetic properties can be superior compared to combination therapies with the single antibiotics, and the antibacterial potency is often enhanced in a synergistic manner. In the second category (antimicrobial conjugates), one functional moiety controls the accumulation of the other part of the conjugate, e.g. by mediating an active transport into the bacterial cell or blocking the efflux. This approach is mostly applied to translocate compounds across the cell envelope of Gram-negative bacteria through membrane-embedded transporters (e.g. siderophore transporters) that provide nutrition and signalling compounds to the cell. Such 'Trojan Horse' approaches can expand the antibacterial activity of compounds against Gram-negative pathogens, or offer new options for natural products that could not be developed as standalone antibiotics, e.g. due to their toxicity.
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Affiliation(s)
- P Klahn
- Department for Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany. and Institute for Organic Chemistry, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany.
| | - M Brönstrup
- Department for Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany.
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188
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Harrison E, Hall JPJ, Paterson S, Spiers AJ, Brockhurst MA. Conflicting selection alters the trajectory of molecular evolution in a tripartite bacteria-plasmid-phage interaction. Mol Ecol 2017; 26:2757-2764. [PMID: 28247474 PMCID: PMC5655702 DOI: 10.1111/mec.14080] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 02/08/2017] [Accepted: 02/08/2017] [Indexed: 01/21/2023]
Abstract
Bacteria engage in a complex network of ecological interactions, which includes mobile genetic elements (MGEs) such as phages and plasmids. These elements play a key role in microbial communities as vectors of horizontal gene transfer but can also be important sources of selection for their bacterial hosts. In natural communities, bacteria are likely to encounter multiple MGEs simultaneously and conflicting selection among MGEs could alter the bacterial evolutionary response to each MGE. Here, we test the effect of interactions with multiple MGEs on bacterial molecular evolution in the tripartite interaction between the bacterium, Pseudomonas fluorescens, the lytic bacteriophage, SBW25φ2, and conjugative plasmid, pQBR103, using genome sequencing of experimentally evolved bacteria. We show that individually, both plasmids and phages impose selection leading to bacterial evolutionary responses that are distinct from bacterial populations evolving without MGEs, but that together, plasmids and phages impose conflicting selection on bacteria, constraining the evolutionary responses observed in pairwise interactions. Our findings highlight the likely difficulties of predicting evolutionary responses to multiple selective pressures from the observed evolutionary responses to each selective pressure alone. Understanding evolution in complex microbial communities comprising many species and MGEs will require that we go beyond studies of pairwise interactions.
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Affiliation(s)
- Ellie Harrison
- Department of Animal and Plant SciencesUniversity of SheffieldSheffieldS10 2TNUK
| | - James P. J. Hall
- Department of Animal and Plant SciencesUniversity of SheffieldSheffieldS10 2TNUK
| | - Steve Paterson
- Institute of Integrative BiologyUniversity of LiverpoolLiverpoolL69 7ZBUK
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189
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Werisch M, Berger U, Berendonk TU. Conjugative plasmids enable the maintenance of low cost non-transmissible plasmids. Plasmid 2017; 91:96-104. [PMID: 28461122 DOI: 10.1016/j.plasmid.2017.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 04/27/2017] [Accepted: 04/27/2017] [Indexed: 11/27/2022]
Abstract
Some plasmids can be transferred by conjugation to other bacterial hosts. But almost half of the plasmids are non-transmissible. These plasmid types can only be transmitted to the daughter cells of their host after bacterial fission. Previous studies suggest that non-transmissible plasmids become extinct in the absence of selection of their encoded traits, as plasmid-free bacteria are more competitive. Here, we aim to identify mechanisms that enable non-transmissible plasmids to persist, even if they are not beneficial. For this purpose, an individual-based model for plasmid population dynamics was set up and carefully tested for structural consistency and plausibility. Our results demonstrate that non-transmissible plasmids can be stably maintained in a population, even if they impose a substantial burden on their host cells growth. A prerequisite is the co-occurrence of an incompatible and costly conjugative plasmid type, which indirectly facilitates the preservation of the non-transmissible type. We suggest that this constellation might be considered as a potential mechanism maintaining plasmids and associated antibiotic resistances. It should be investigated in upcoming laboratory experiments.
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Affiliation(s)
- Martin Werisch
- Technische Universität Dresden, Department of Forest Sciences, Institute of Forest Growth and Forest Computer Sciences, Tharandt 01735, Germany.
| | - Uta Berger
- Technische Universität Dresden, Department of Forest Sciences, Institute of Forest Growth and Forest Computer Sciences, Tharandt 01735, Germany
| | - Thomas U Berendonk
- Technische Universität Dresden, Department of Hydro Sciences, Institute of Hydrobiology, Dresden 01217, Germany
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190
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Blokesch M. In and out-contribution of natural transformation to the shuffling of large genomic regions. Curr Opin Microbiol 2017; 38:22-29. [PMID: 28458094 DOI: 10.1016/j.mib.2017.04.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 04/01/2017] [Accepted: 04/06/2017] [Indexed: 01/28/2023]
Abstract
Naturally competent bacteria can pull free DNA from their surroundings. This incoming DNA can serve various purposes, ranging from acting as a source of nutrients or DNA stretches for repair to the acquisition of novel genetic information. The latter process defines the natural competence for transformation as a mode of horizontal gene transfer (HGT) and led to its discovery almost a century ago. However, although it is widely accepted that natural competence can contribute to the spread of genetic material among prokaryotes, the question remains whether this mode of HGT can foster the transfer of larger DNA regions or only transfers shorter fragments, given that extracellular DNA is often heavily fragmented. Here, I outline examples of competence-mediated movement of large genomic segments. Moreover, I discuss a recent proposition that transformation is used to cure bacteria of selfish mobile genetic elements. Such a transformation-mediated genome maintenance mechanism could indeed be an important and underappreciated function of natural competence.
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Affiliation(s)
- Melanie Blokesch
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
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191
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192
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Bedhomme S, Perez Pantoja D, Bravo IG. Plasmid and clonal interference during post horizontal gene transfer evolution. Mol Ecol 2017; 26:1832-1847. [PMID: 28206693 DOI: 10.1111/mec.14056] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 01/31/2017] [Accepted: 02/08/2017] [Indexed: 01/12/2023]
Abstract
Plasmids are nucleic acid molecules that can drive their own replication in a living cell. They can be transmitted horizontally and can thrive in the host cell to high-copy numbers. Plasmid replication and gene expression consume cellular resources and cells carrying plasmids incur fitness costs. But many plasmids carry genes that can be beneficial under certain conditions, allowing the cell to endure in the presence of antibiotics, toxins, competitors or parasites. Horizontal transfer of plasmid-encoded genes can thus instantaneously confer differential adaptation to local or transient selection conditions. This conflict between cellular fitness and plasmid spread sets the scene for multilevel selection processes. We have engineered a system to study the short-term evolutionary impact of different synonymous versions of a plasmid-encoded antibiotic resistance gene. Applying experimental evolution under different selection conditions and deep sequencing allowed us to show rapid local adaptation to the presence of antibiotic and to the specific version of the resistance gene transferred. We describe the presence of clonal interference at two different levels: at the within-cell level, because a single cell can carry several plasmids, and at the between-cell level, because a bacterial population may contain several clones carrying different plasmids and displaying different fitness in the presence/absence of antibiotic. Understanding the within-cell and between-cell dynamics of plasmids after horizontal gene transfer is essential to unravel the dense network of mobile elements underlying the worldwide threat to public health of antibiotic resistance.
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Affiliation(s)
- S Bedhomme
- Centre d'Ecologie Fonctionnelle et Evolutive, UMR CNRS 5175, 34293, Montpellier, France.,Laboratory MIVEGEC, UMR CNRS 5290, IRD 224, UM, Centre National de la Recherche Scientifique, 911 avenue Agropolis, BP64501, 34394, Montpellier Cedex 05, France
| | - D Perez Pantoja
- Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación, Universidad Tecnológica Metropolitana, Ignacio Valdivieso 2409, P.O. Box 8940577, San Joaquín, Santiago, Chile
| | - I G Bravo
- Laboratory MIVEGEC, UMR CNRS 5290, IRD 224, UM, Centre National de la Recherche Scientifique, 911 avenue Agropolis, BP64501, 34394, Montpellier Cedex 05, France
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193
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Choudoir MJ, Panke-Buisse K, Andam CP, Buckley DH. Genome Surfing As Driver of Microbial Genomic Diversity. Trends Microbiol 2017; 25:624-636. [PMID: 28283403 DOI: 10.1016/j.tim.2017.02.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/03/2017] [Accepted: 02/10/2017] [Indexed: 01/20/2023]
Abstract
Historical changes in population size, such as those caused by demographic range expansions, can produce nonadaptive changes in genomic diversity through mechanisms such as gene surfing. We propose that demographic range expansion of a microbial population capable of horizontal gene exchange can result in genome surfing, a mechanism that can cause widespread increase in the pan-genome frequency of genes acquired by horizontal gene exchange. We explain that patterns of genetic diversity within Streptomyces are consistent with genome surfing, and we describe several predictions for testing this hypothesis both in Streptomyces and in other microorganisms.
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Affiliation(s)
- Mallory J Choudoir
- School of Integrative Plant Science, Cornell University, Ithaca, NY 14850 USA
| | - Kevin Panke-Buisse
- School of Integrative Plant Science, Cornell University, Ithaca, NY 14850 USA
| | - Cheryl P Andam
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham NH 03824, USA
| | - Daniel H Buckley
- School of Integrative Plant Science, Cornell University, Ithaca, NY 14850 USA.
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194
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Lu Y, Zeng J, Wu B, E S, Wang L, Cai R, Zhang N, Li Y, Huang X, Huang B, Chen C. Quorum Sensing N-acyl Homoserine Lactones-SdiA Suppresses Escherichia coli- Pseudomonas aeruginosa Conjugation through Inhibiting traI Expression. Front Cell Infect Microbiol 2017; 7:7. [PMID: 28164039 PMCID: PMC5247672 DOI: 10.3389/fcimb.2017.00007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/05/2017] [Indexed: 01/03/2023] Open
Abstract
Conjugation is a key mechanism for horizontal gene transfer and plays an important role in bacterial evolution, especially with respect to antibiotic resistance. However, little is known about the role of donor and recipient cells in regulation of conjugation. Here, using an Escherichia coli (SM10λπ)-Pseudomonas aeruginosa (PAO1) conjugation model, we demonstrated that deficiency of lasI/rhlI, genes associated with generation of the quorum sensing signals N-acyl homoserine lactones (AHLs) in PAO1, or deletion of the AHLs receptor SdiA in the donor SM10λπ both facilitated conjugation. When using another AHLs-non-producing E. coli strain EC600 as recipient cells, deficiency of sdiA in donor SM10λπ hardly affect the conjugation. More importantly, in the presence of exogenous AHLs, the conjugation efficiency between SM10λπ and EC600 was dramatically decreased, while deficiency of sdiA in SM10λπ attenuated AHLs-inhibited conjugation. These data suggest the conjugation suppression function of AHLs-SdiA chemical signaling. Further bioinformatics analysis, β-galactosidase reporter system and electrophoretic mobility shift assays characterized the binding site of SdiA on the promoter region of traI gene. Furthermore, deletion of lasI/rhlI or sdiA promoted traI mRNA expression in SM10λπ and PAO1 co-culture system, which was abrogated by AHLs. Collectively, our results provide new insight into an important contribution of quorum sensing system AHLs-SdiA to the networks that regulate conjugation.
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Affiliation(s)
- Yang Lu
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese MedicineGuangzhou, China; Postdoctoral Mobile Station, Guangzhou University of Chinese MedicineGuangzhou, China
| | - Jianming Zeng
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine Guangzhou, China
| | - Binning Wu
- The Second Clinical College, Guangzhou University of Chinese Medicine Guangzhou, China
| | - Shunmei E
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine Guangzhou, China
| | - Lina Wang
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine Guangzhou, China
| | - Renxin Cai
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine Guangzhou, China
| | - Ni Zhang
- Clinical Microbiology Laboratory, Guangdong Academy of Medical Science and Guangdong General Hospital Guangzhou, China
| | - Youqiang Li
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine Guangzhou, China
| | - Xianzhang Huang
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese MedicineGuangzhou, China; Postdoctoral Mobile Station, Guangzhou University of Chinese MedicineGuangzhou, China
| | - Bin Huang
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University Guangzhou, China
| | - Cha Chen
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine Guangzhou, China
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195
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Horizontally acquired AT-rich genes in Escherichia coli cause toxicity by sequestering RNA polymerase. Nat Microbiol 2017; 2:16249. [PMID: 28067866 DOI: 10.1038/nmicrobiol.2016.249] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 11/08/2016] [Indexed: 11/09/2022]
Abstract
Horizontal gene transfer permits rapid dissemination of genetic elements between individuals in bacterial populations. Transmitted DNA sequences may encode favourable traits. However, if the acquired DNA has an atypical base composition, it can reduce host fitness. Consequently, bacteria have evolved strategies to minimize the harmful effects of foreign genes. Most notably, xenogeneic silencing proteins bind incoming DNA that has a higher AT content than the host genome. An enduring question has been why such sequences are deleterious. Here, we showed that the toxicity of AT-rich DNA in Escherichia coli frequently results from constitutive transcription initiation within the coding regions of genes. Left unchecked, this causes titration of RNA polymerase and a global downshift in host gene expression. Accordingly, a mutation in RNA polymerase that diminished the impact of AT-rich DNA on host fitness reduced transcription from constitutive, but not activator-dependent, promoters.
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196
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Vazquez-Gutierrez P, Stevens MJA, Gehrig P, Barkow-Oesterreicher S, Lacroix C, Chassard C. The extracellular proteome of two Bifidobacterium species reveals different adaptation strategies to low iron conditions. BMC Genomics 2017; 18:41. [PMID: 28061804 PMCID: PMC5219805 DOI: 10.1186/s12864-016-3472-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 12/26/2016] [Indexed: 12/30/2022] Open
Abstract
Background Bifidobacteria are among the first anaerobic bacteria colonizing the gut. Bifidobacteria require iron for growth and their iron-sequestration mechanisms are important for their fitness and possibly inhibit enteropathogens. Here we used combined genomic and proteomic analyses to characterize adaptations to low iron conditions of B. kashiwanohense PV20-2 and B. pseudolongum PV8-2, 2 strains isolated from the feces of iron-deficient African infants and selected for their high iron-sequestering ability. Results Analyses of the genome contents revealed evolutionary adaptation to low iron conditions. A ferric and a ferrous iron operon encoding binding proteins and transporters were found in both strains. Remarkably, the ferric iron operon of B. pseudolongum PV8-2 is not found in other B. pseudolongum strains and likely acquired via horizontal gene transfer. The genome B. kashiwanohense PV20-2 harbors a unique region encoding genes putatively involved in siderophore production. Additionally, the secretomes of the two strains grown under low-iron conditions were analyzed using a combined genomic-proteomic approach. A ferric iron transporter was found in the secretome of B. pseudolongum PV8-2, while ferrous binding proteins were detected in the secretome of B. kashiwanohense PV20-2, suggesting different strategies to take up iron in the strains. In addition, proteins such as elongation factors, a glyceraldehyde-3-phosphate dehydrogenase, and the stress proteins GroEL and DnaK were identified in both secretomes. These proteins have been previously associated with adhesion of lactobacilli to epithelial cells. Conclusion Analyses of the genome and secretome of B. kashiwanohense PV20-2 and B. pseudolongum PV8-2 revealed different adaptations to low iron conditions and identified extracellular proteins for iron transport. The identified extracellular proteins might be involved in competition for iron in the gastrointestinal tract. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3472-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Pamela Vazquez-Gutierrez
- Laboratory of Food Biotechnology, ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 7, 8092, Zurich, Switzerland
| | - Marc J A Stevens
- Laboratory of Food Biotechnology, ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 7, 8092, Zurich, Switzerland
| | - Peter Gehrig
- Functional Genomics Center Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | | | - Christophe Lacroix
- Laboratory of Food Biotechnology, ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 7, 8092, Zurich, Switzerland.
| | - Christophe Chassard
- Laboratory of Food Biotechnology, ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 7, 8092, Zurich, Switzerland.,Present Address: Institut National de la Recherche Agronomique, UR 545 URF, 15000, Aurillac, France
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197
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The effect of competition and horizontal trait inheritance on invasion, fixation, and polymorphism. J Theor Biol 2016; 411:48-58. [DOI: 10.1016/j.jtbi.2016.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 09/19/2016] [Accepted: 10/06/2016] [Indexed: 11/19/2022]
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198
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San Millan A, Escudero JA, Gifford DR, Mazel D, MacLean RC. Multicopy plasmids potentiate the evolution of antibiotic resistance in bacteria. Nat Ecol Evol 2016; 1:10. [PMID: 28812563 DOI: 10.1038/s41559-016-0010] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 08/10/2016] [Indexed: 12/11/2022]
Abstract
Plasmids are thought to play a key role in bacterial evolution by acting as vehicles for horizontal gene transfer, but the role of plasmids as catalysts of gene evolution remains unexplored. We challenged populations of Escherichia coli carrying the blaTEM-1 β-lactamase gene on either the chromosome or a multicopy plasmid (19 copies per cell) with increasing concentrations of ceftazidime. The plasmid accelerated resistance evolution by increasing the rate of appearance of novel TEM-1 mutations, thereby conferring resistance to ceftazidime, and then by amplifying the effect of TEM-1 mutations due to the increased gene dosage. Crucially, this dual effect was necessary and sufficient for the evolution of clinically relevant levels of resistance. Subsequent evolution occurred by mutations in a regulatory RNA that increased the plasmid copy number, resulting in marginal gains in ceftazidime resistance. These results uncover a role for multicopy plasmids as catalysts for the evolution of antibiotic resistance in bacteria.
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Affiliation(s)
- Alvaro San Millan
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.,Department of Microbiology, Hospital Universitario Ramon y Cajal (IRYCIS), 28034 Madrid, Spain
| | - Jose Antonio Escudero
- Institut Pasteur, Unité de Plasticité du Génome Bactérien, Département Génomes et Génétique, 28 Rue du Dr. Roux, 75015 Paris, France.,CNRS, UMR3525, 28 Rue du Dr. Roux, 75015 Paris, France
| | - Danna R Gifford
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK
| | - Didier Mazel
- Institut Pasteur, Unité de Plasticité du Génome Bactérien, Département Génomes et Génétique, 28 Rue du Dr. Roux, 75015 Paris, France.,CNRS, UMR3525, 28 Rue du Dr. Roux, 75015 Paris, France
| | - R Craig MacLean
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK
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199
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Gillings MR. Lateral gene transfer, bacterial genome evolution, and the Anthropocene. Ann N Y Acad Sci 2016; 1389:20-36. [DOI: 10.1111/nyas.13213] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 07/20/2016] [Accepted: 07/28/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Michael R. Gillings
- Genes to Geoscience Research Centre, Department of Biological Sciences Macquarie University Sydney New South Wales Australia
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200
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Booth A, Mariscal C, Doolittle WF. The Modern Synthesis in the Light of Microbial Genomics. Annu Rev Microbiol 2016; 70:279-97. [DOI: 10.1146/annurev-micro-102215-095456] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Austin Booth
- Department of Philosophy, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada;
| | - Carlos Mariscal
- Department of Philosophy, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada;
- Department of Philosophy, University of Nevada, Reno, Nevada 89557
| | - W. Ford Doolittle
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax B3H 4R2, Nova Scotia, Canada;
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