1
|
Nikolic N, Anagnostidis V, Tiwari A, Chait R, Gielen F. Droplet-based methodology for investigating bacterial population dynamics in response to phage exposure. Front Microbiol 2023; 14:1260196. [PMID: 38075890 PMCID: PMC10703435 DOI: 10.3389/fmicb.2023.1260196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 10/23/2023] [Indexed: 02/12/2024] Open
Abstract
An alarming rise in antimicrobial resistance worldwide has spurred efforts into the search for alternatives to antibiotic treatments. The use of bacteriophages, bacterial viruses harmless to humans, represents a promising approach with potential to treat bacterial infections (phage therapy). Recent advances in microscopy-based single-cell techniques have allowed researchers to develop new quantitative methodologies for assessing the interactions between bacteria and phages, especially the ability of phages to eradicate bacterial pathogen populations and to modulate growth of both commensal and pathogen populations. Here we combine droplet microfluidics with fluorescence time-lapse microscopy to characterize the growth and lysis dynamics of the bacterium Escherichia coli confined in droplets when challenged with phage. We investigated phages that promote lysis of infected E. coli cells, specifically, a phage species with DNA genome, T7 (Escherichia virus T7) and two phage species with RNA genomes, MS2 (Emesvirus zinderi) and Qβ (Qubevirus durum). Our microfluidic trapping device generated and immobilized picoliter-sized droplets, enabling stable imaging of bacterial growth and lysis in a temperature-controlled setup. Temporal information on bacterial population size was recorded for up to 25 h, allowing us to determine growth rates of bacterial populations and helping us uncover the extent and speed of phage infection. In the long-term, the development of novel microfluidic single-cell and population-level approaches will expedite research towards fundamental understanding of the genetic and molecular basis of rapid phage-induced lysis and eco-evolutionary aspects of bacteria-phage dynamics, and ultimately help identify key factors influencing the success of phage therapy.
Collapse
Affiliation(s)
- Nela Nikolic
- Living Systems Institute, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
- Department of Physics and Astronomy, Faculty of Environment, Science and Economy, University of Exeter, Exeter, United Kingdom
- Translational Research Exchange @ Exeter, University of Exeter, Exeter, United Kingdom
| | - Vasileios Anagnostidis
- Living Systems Institute, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
- Department of Physics and Astronomy, Faculty of Environment, Science and Economy, University of Exeter, Exeter, United Kingdom
| | - Anuj Tiwari
- Living Systems Institute, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Remy Chait
- Living Systems Institute, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
- Department of Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Fabrice Gielen
- Living Systems Institute, Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
- Department of Physics and Astronomy, Faculty of Environment, Science and Economy, University of Exeter, Exeter, United Kingdom
| |
Collapse
|
2
|
Balcão VM, Belline BG, Silva EC, Almeida PFFB, Baldo DÂ, Amorim LRP, Oliveira Júnior JM, Vila MMDC, Del Fiol FS. Isolation and Molecular Characterization of Two Novel Lytic Bacteriophages for the Biocontrol of Escherichia coli in Uterine Infections: In Vitro and Ex Vivo Preliminary Studies in Veterinary Medicine. Pharmaceutics 2022; 14:2344. [PMID: 36365162 PMCID: PMC9692438 DOI: 10.3390/pharmaceutics14112344] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 10/23/2022] [Accepted: 10/27/2022] [Indexed: 09/18/2023] Open
Abstract
E. coli is one of the etiological agents responsible for pyometra in female dogs, with conventional treatment involving ovariohysterectomy. Here, we report the isolation and full characterization of two novel lytic phages, viz. vB_EcoM_Uniso11 (ph0011) and vB_EcoM_Uniso21 (ph0021). Both phages belong to the order Caudovirales and present myovirus-like morphotypes, with phage ph0011 being classified as Myoviridae genus Asteriusvirus and phage ph0021 being classified as Myoviridae genus Tequatrovirus, based on their complete genome sequences. The 348,288 bp phage ph0011 and 165,222 bp phage ph0021 genomes do not encode toxins, integrases or antimicrobial resistance genes neither depolymerases related sequences. Both phages were shown to be effective against at least twelve E. coli clinical isolates in in vitro antibacterial activity assays. Based on their features, both phages have potential for controlling pyometra infections caused by E. coli. Phage ph0011 (reduction of 4.24 log CFU/mL) was more effective than phage ph0021 (reduction of 1.90 log CFU/mL) after 12 h of incubation at MOI 1000. As a cocktail, the two phages were highly effective in reducing the bacterial load (reduction of 5.57 log CFU/mL) at MOI 100, after 12 h of treatment. Both phages were structurally and functionally stabilized in vaginal egg formulations.
Collapse
Affiliation(s)
- Victor M. Balcão
- PhageLab, Laboratory of Biofilms and Bacteriophages, University of Sorocaba, Sorocaba 18023-000, Brazil
- Department of Biology and CESAM, Campus Universitário de Santiago, University of Aveiro, P-3810-193 Aveiro, Portugal
| | - Bianca G. Belline
- PhageLab, Laboratory of Biofilms and Bacteriophages, University of Sorocaba, Sorocaba 18023-000, Brazil
| | - Erica C. Silva
- PhageLab, Laboratory of Biofilms and Bacteriophages, University of Sorocaba, Sorocaba 18023-000, Brazil
| | - Pablo F. F. B. Almeida
- PhageLab, Laboratory of Biofilms and Bacteriophages, University of Sorocaba, Sorocaba 18023-000, Brazil
| | - Denicezar Â. Baldo
- PhageLab, Laboratory of Biofilms and Bacteriophages, University of Sorocaba, Sorocaba 18023-000, Brazil
| | - Lara R. P. Amorim
- Department of Education, Faculty of Sciences, University of Porto, P-4169-007 Porto, Portugal
| | - José M. Oliveira Júnior
- PhageLab, Laboratory of Biofilms and Bacteriophages, University of Sorocaba, Sorocaba 18023-000, Brazil
| | - Marta M. D. C. Vila
- PhageLab, Laboratory of Biofilms and Bacteriophages, University of Sorocaba, Sorocaba 18023-000, Brazil
| | - Fernando S. Del Fiol
- PhageLab, Laboratory of Biofilms and Bacteriophages, University of Sorocaba, Sorocaba 18023-000, Brazil
| |
Collapse
|
3
|
Jin T, Yin J. Patterns of virus growth across the diversity of life. Integr Biol (Camb) 2021; 13:44-59. [PMID: 33616184 DOI: 10.1093/intbio/zyab001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/24/2020] [Accepted: 01/04/2021] [Indexed: 01/14/2023]
Abstract
Although viruses in their natural habitats add up to less than 10% of the biomass, they contribute more than 90% of the genome sequences [1]. These viral sequences or 'viromes' encode viruses that populate the Earth's oceans [2, 3] and terrestrial environments [4, 5], where their infections impact life across diverse ecological niches and scales [6, 7], including humans [8-10]. Most viruses have yet to be isolated and cultured [11-13], and surprisingly few efforts have explored what analysis of available data might reveal about their nature. Here, we compiled and analyzed seven decades of one-step growth and other data for viruses from six major families, including their infections of archaeal, bacterial and eukaryotic hosts [14-191]. We found that the use of host cell biomass for virus production was highest for archaea at 10%, followed by bacteria at 1% and eukarya at 0.01%, highlighting the degree to which viruses of archaea and bacteria exploit their host cells. For individual host cells, the yield of virus progeny spanned a relatively narrow range (10-1000 infectious particles per cell) compared with the million-fold difference in size between the smallest and largest cells. Furthermore, healthy and infected host cells were remarkably similar in the time they needed to multiply themselves or their virus progeny. Specifically, the doubling time of healthy cells and the delay time for virus release from infected cells were not only correlated (r = 0.71, p < 10-10, n = 101); they also spanned the same range from tens of minutes to about a week. These results have implications for better understanding the growth, spread and persistence of viruses in complex natural habitats that abound with diverse hosts, including humans and their associated microbes.
Collapse
Affiliation(s)
- Tianyi Jin
- Chemical and Biological Engineering, Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - John Yin
- Chemical and Biological Engineering, Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| |
Collapse
|
4
|
Simulation of the M13 life cycle I: Assembly of a genetically-structured deterministic chemical kinetic simulation. Virology 2016; 500:259-274. [PMID: 27644585 DOI: 10.1016/j.virol.2016.08.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/16/2016] [Accepted: 08/18/2016] [Indexed: 11/22/2022]
Abstract
To expand the quantitative, systems level understanding and foster the expansion of the biotechnological applications of the filamentous bacteriophage M13, we have unified the accumulated quantitative information on M13 biology into a genetically-structured, experimentally-based computational simulation of the entire phage life cycle. The deterministic chemical kinetic simulation explicitly includes the molecular details of DNA replication, mRNA transcription, protein translation and particle assembly, as well as the competing protein-protein and protein-nucleic acid interactions that control the timing and extent of phage production. The simulation reproduces the holistic behavior of M13, closely matching experimentally reported values of the intracellular levels of phage species and the timing of events in the M13 life cycle. The computational model provides a quantitative description of phage biology, highlights gaps in the present understanding of M13, and offers a framework for exploring alternative mechanisms of regulation in the context of the complete M13 life cycle.
Collapse
|
5
|
Paff ML, Nuismer SL, Ellington A, Molineux IJ, Bull JJ. Virus wars: using one virus to block the spread of another. PeerJ 2016; 4:e2166. [PMID: 27413636 PMCID: PMC4933091 DOI: 10.7717/peerj.2166] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 06/02/2016] [Indexed: 12/22/2022] Open
Abstract
The failure of traditional interventions to block and cure HIV infections has led to novel proposals that involve treating infections with therapeutic viruses-infectious viruses that specifically inhibit HIV propagation in the host. Early efforts in evaluating these proposals have been limited chiefly to mathematical models of dynamics, for lack of suitable empirical systems. Here we propose, develop and analyze an empirical system of a therapeutic virus that protects a host cell population against a lethal virus. The empirical system uses E. coli bacteria as the host cell population, an RNA phage as the lethal virus and a filamentous phage as the therapeutic virus. Basic dynamic properties are established for each virus alone and then together. Observed dynamics broadly agree with those predicted by a computer simulation model, although some differences are noted. Two cases of dynamics are contrasted, differing in whether the therapeutic virus is introduced before the lethal virus or after the lethal virus. The therapeutic virus increases in both cases but by different mechanisms. With the therapeutic virus introduced first, it spreads infectiously without any appreciable change in host dynamics. With the therapeutic virus introduced second, host abundance is depressed at the time therapy is applied; following an initial period of therapeutic virus spread by infection, the subsequent rise of protection is through reproduction by hosts already protected. This latter outcome is due to inheritance of the therapeutic virus state when the protected cell divides. Overall, the work establishes the feasibility and robustness to details of a viral interference using a therapeutic virus.
Collapse
Affiliation(s)
- Matthew L Paff
- Department of Integrative Biology, University of Texas, Austin, TX, United States; The Institute for Cellular and Molecular Biology, University of Texas, Austin, TX, United States
| | - Scott L Nuismer
- Department of Biological Sciences, University of Idaho , Moscow , ID , United States
| | - Andrew Ellington
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, United States; The Institute for Cellular and Molecular Biology, University of Texas, Austin, TX, United States; Center for Systems, Biology, University of Texas at Austin, Austin, TX, United States
| | - Ian J Molineux
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, United States; The Institute for Cellular and Molecular Biology, University of Texas, Austin, TX, United States
| | - James J Bull
- Department of Integrative Biology, University of Texas, Austin, TX, United States; The Institute for Cellular and Molecular Biology, University of Texas, Austin, TX, United States; Center for Computational Biology and Bioinformatics, University of Texas, Austin, TX, United States
| |
Collapse
|
6
|
Abstract
UNLABELLED Changes in protein function and other biological properties, such as RNA structure, are crucial for adaptation of organisms to novel or inhibitory environments. To investigate how mutations that do not alter amino acid sequence may be positively selected, we performed a thermal adaptation experiment using the single-stranded RNA bacteriophage Qβ in which the culture temperature was increased from 37.2°C to 41.2°C and finally to an inhibitory temperature of 43.6°C in a stepwise manner in three independent lines. Whole-genome analysis revealed 31 mutations, including 14 mutations that did not result in amino acid sequence alterations, in this thermal adaptation. Eight of the 31 mutations were observed in all three lines. Reconstruction and fitness analyses of Qβ strains containing only mutations observed in all three lines indicated that five mutations that did not result in amino acid sequence changes but increased the amplification ratio appeared in the course of adaptation to growth at 41.2°C. Moreover, these mutations provided a suitable genetic background for subsequent mutations, altering the fitness contribution from deleterious to beneficial. These results clearly showed that mutations that do not alter the amino acid sequence play important roles in adaptation of this single-stranded RNA virus to elevated temperature. IMPORTANCE Recent studies using whole-genome analysis technology suggested the importance of mutations that do not alter the amino acid sequence for adaptation of organisms to novel environmental conditions. It is necessary to investigate how these mutations may be positively selected and to determine to what degree such mutations that do not alter amino acid sequences contribute to adaptive evolution. Here, we report the roles of these silent mutations in thermal adaptation of RNA bacteriophage Qβ based on experimental evolution during which Qβ showed adaptation to growth at an inhibitory temperature. Intriguingly, four synonymous mutations and one mutation in the untranslated region that spread widely in the Qβ population during the adaptation process at moderately high temperature provided a suitable genetic background to alter the fitness contribution of subsequent mutations from deleterious to beneficial at a higher temperature.
Collapse
|
7
|
Reed CA, Langlais C, Wang IN, Young R. A(2) expression and assembly regulates lysis in Qβ infections. MICROBIOLOGY (READING, ENGLAND) 2013; 159:507-514. [PMID: 23329676 PMCID: PMC3709820 DOI: 10.1099/mic.0.064790-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 12/29/2012] [Accepted: 01/05/2013] [Indexed: 01/19/2023]
Abstract
The capsids of ssRNA phages comprise a single copy of an ~45 kDa maturation protein that serves to recognize the conjugative pilus as receptor, to protect the ends of the viral RNA and also to escort the genomic RNA into the host cytoplasm. In the Alloleviviridae, represented by the canonical phage Qβ, the maturation protein A(2) also causes lysis. This is achieved by inhibiting the activity of MurA, which catalyses the first committed step of murein biosynthesis. Previously, it was shown that Qβ virions, with a single copy of A(2), inhibit MurA activity. This led to a model for lysis timing in which, during phage infection, A(2) is not active as a MurA inhibitor until assembled into virion particles, thus preventing premature lysis before a sufficient yield of viable progeny has accumulated. Here we report that MurA inactivates purified Qβ particles, casting doubt on the notion that A(2) must assemble into particles prior to MurA inhibition. Furthermore, quantification of A(2) protein induced from a plasmid indicated that lysis is entrained when the amount of the lysis protein is approximately equimolar to that of cellular MurA. Qβ por mutants, isolated as suppressors that overcome a murA(rat) mutation that reduces the affinity of MurA for A(2), were shown to be missense mutations in A(2) that increase the translation of the maturation protein. Because of the increased production of A(2), the por mutants have an attenuated infection cycle and reduced burst size, indicating that a delicate balance between assembled and unassembled A(2) levels regulates lysis timing.
Collapse
Affiliation(s)
- Catrina A Reed
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843-2128, USA
| | - Carrie Langlais
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843-2128, USA
| | - Ing-Nang Wang
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843-2128, USA
| | - Ry Young
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843-2128, USA
| |
Collapse
|
8
|
García-Villada L, Drake JW. The three faces of riboviral spontaneous mutation: spectrum, mode of genome replication, and mutation rate. PLoS Genet 2012; 8:e1002832. [PMID: 22844250 PMCID: PMC3405988 DOI: 10.1371/journal.pgen.1002832] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 05/31/2012] [Indexed: 11/19/2022] Open
Abstract
Riboviruses (RNA viruses without DNA replication intermediates) are the most abundant pathogens infecting animals and plants. Only a few riboviral infections can be controlled with antiviral drugs, mainly because of the rapid appearance of resistance mutations. Little reliable information is available concerning i) kinds and relative frequencies of mutations (the mutational spectrum), ii) mode of genome replication and mutation accumulation, and iii) rates of spontaneous mutation. To illuminate these issues, we developed a model in vivo system based on phage Qß infecting its natural host, Escherichia coli. The Qß RT gene encoding the Read-Through protein was used as a mutation reporter. To reduce uncertainties in mutation frequencies due to selection, the experimental Qß populations were established after a single cycle of infection and selection against RT− mutants during phage growth was ameliorated by plasmid-based RT complementation in trans. The dynamics of Qß genome replication were confirmed to reflect the linear process of iterative copying (the stamping-machine mode). A total of 32 RT mutants were detected among 7,517 Qß isolates. Sequencing analysis of 45 RT mutations revealed a spectrum dominated by 39 transitions, plus 4 transversions and 2 indels. A clear template•primer mismatch bias was observed: A•C>C•A>U•G>G•U> transversion mismatches. The average mutation rate per base replication was ≈9.1×10−6 for base substitutions and ≈2.3×10−7 for indels. The estimated mutation rate per genome replication, μg, was ≈0.04 (or, per phage generation, ≈0.08), although secondary RT mutations arose during the growth of some RT mutants at a rate about 7-fold higher, signaling the possible impact of transitory bouts of hypermutation. These results are contrasted with those previously reported for other riboviruses to depict the current state of the art in riboviral mutagenesis. Viral disease is a subject of major concern in public health. Diseases produced by riboviruses (RNA viruses sensu stricto) represent a special urgency, because these viruses display an exceptional capability to generate resistance mutations against antiviral drugs. Unfortunately, little is known about the rate and nature of spontaneous mutation in riboviruses. Thus, characterization of their mutation process may be helpful in the development of improved ways to counteract riboviral diseases. In this study, we investigated the mutation process in vivo of a model ribovirus, the bacteriophage Qß, focusing on three key aspects: i) the kinds and relative frequencies of mutations, ii) the mode of genome replication, and iii) the rate of spontaneous mutation. Our results, combined with other information about riboviral mutagenesis, depict a ribovirus mutation spectrum largely dominated by transitions, a predominantly linear mode of genome replication, and a mutation rate per genome replication on the order of 0.04 for bacteriophages and plant viruses but perhaps an order of magnitude higher for mammalian riboviruses.
Collapse
Affiliation(s)
| | - John W. Drake
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
- * E-mail:
| |
Collapse
|
9
|
Inomata T, Kimura H, Hayasaka H, Shiozaki A, Fujita Y, Kashiwagi A. Quantitative comparison of the RNA bacteriophage Qβ infection cycle in rich and minimal media. Arch Virol 2012; 157:2163-9. [DOI: 10.1007/s00705-012-1419-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Accepted: 06/04/2012] [Indexed: 02/02/2023]
|
10
|
Smith MT, Varner CT, Bush DB, Bundy BC. The incorporation of the A2 protein to produce novel Qβ virus-like particles using cell-free protein synthesis. Biotechnol Prog 2011; 28:549-55. [PMID: 22125293 DOI: 10.1002/btpr.744] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 10/19/2011] [Indexed: 12/22/2022]
Abstract
Virus-like particles (VLPs) have been employed for a number of nanometric applications because they self-assemble, exhibit a high degree of symmetry, and can be genetically and chemically modified. However, high symmetry does not allow for a single unique modification site on the VLP. Here, we demonstrate the co-expression of the cytotoxic A2 protein and the coat protein of the bacteriophage Qβ to form a nearly monodispersed population of novel VLPs. Cell-free protein synthesis allows for direct access and optimization of protein-synthesis and VLP-assembly. The A2 is shown to be incorporated at high efficiency, approaching a theoretical maximum of one A2 per VLP. This work demonstrates de novo production of a novel VLP, which contains a unique site that has the potential for future nanometric engineering applications.
Collapse
Affiliation(s)
- Mark T Smith
- Dept. of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
| | | | | | | |
Collapse
|
11
|
Kashiwagi A, Yomo T. Ongoing phenotypic and genomic changes in experimental coevolution of RNA bacteriophage Qβ and Escherichia coli. PLoS Genet 2011; 7:e1002188. [PMID: 21829387 PMCID: PMC3150450 DOI: 10.1371/journal.pgen.1002188] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 06/01/2011] [Indexed: 01/21/2023] Open
Abstract
According to the Red Queen hypothesis or arms race dynamics, coevolution drives continuous adaptation and counter-adaptation. Experimental models under simplified environments consisting of bacteria and bacteriophages have been used to analyze the ongoing process of coevolution, but the analysis of both parasites and their hosts in ongoing adaptation and counter-adaptation remained to be performed at the levels of population dynamics and molecular evolution to understand how the phenotypes and genotypes of coevolving parasite–host pairs change through the arms race. Copropagation experiments with Escherichia coli and the lytic RNA bacteriophage Qβ in a spatially unstructured environment revealed coexistence for 54 days (equivalent to 163–165 replication generations of Qβ) and fitness analysis indicated that they were in an arms race. E. coli first adapted by developing partial resistance to infection and later increasing specific growth rate. The phage counter-adapted by improving release efficiency with a change in host specificity and decrease in virulence. Whole-genome analysis indicated that the phage accumulated 7.5 mutations, mainly in the A2 gene, 3.4-fold faster than in Qβ propagated alone. E. coli showed fixation of two mutations (in traQ and csdA) faster than in sole E. coli experimental evolution. These observations suggest that the virus and its host can coexist in an evolutionary arms race, despite a difference in genome mutability (i.e., mutations per genome per replication) of approximately one to three orders of magnitude. To examine the ongoing changes driven by host–parasite interactions, we have constructed a coevolution model consisting of Escherichia coli and the lytic RNA bacteriophage Qβ (Qβ) in a spatially unstructured environment. In coevolution through 54 daily copropagations of the parasite and its host, E. coli first evolved partial resistance to infection and later accelerated its specific growth rate, while the phage counter-adapted by improving release efficiency with a change in host specificity and a decrease in virulence. Whole-genome analysis of E. coli and Qβ revealed accelerated molecular evolution in comparison with Qβ propagation in this study and E. coli sole passage reported previously. The results of the present study indicated that, despite the large difference in mutability of their genomes (approximately one to three orders of magnitude difference), a host with larger genome size (4.6 Mbp) and a lower spontaneous mutation rate (5.4×10−10 per bp per replication) and a parasite with a smaller genome size (4,217 bases) and a higher mutation rate (1.5×10−3 to 1.5×10−5 per base per replication) were capable of changing their phenotypes to coexist in an arms race.
Collapse
Affiliation(s)
- Akiko Kashiwagi
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori, Japan
- * E-mail: (AK); (TY)
| | - Tetsuya Yomo
- Graduate School of Information Science and Technology, Osaka University, Osaka, Japan
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Dynamical Micro-Scale Reaction Environment Project, Exploratory Research for Advanced Technology, Japan Science and Technology Agency, Osaka, Japan
- * E-mail: (AK); (TY)
| |
Collapse
|
12
|
Ichihashi N, Matsuura T, Hosoda K, Yomo T. Identification of two forms of Q{beta} replicase with different thermal stabilities but identical RNA replication activity. J Biol Chem 2010; 285:37210-7. [PMID: 20858892 DOI: 10.1074/jbc.m110.117846] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The enzyme Qβ replicase is an RNA-dependent RNA polymerase, which plays a central role in infection by the simple single-stranded RNA virus bacteriophage Qβ. This enzyme has been used in a number of applications because of its unique activity in amplifying RNA from an RNA template. Determination of the thermal stability of Qβ replicase is important to gain an understanding of its function and potential applications, but data reported to date have been contradictory. Here, we provide evidence that these previous inconsistencies were due to the heterogeneous forms of the replicase with different stabilities. We purified two forms of replicase expressed in Escherichia coli, which differed in their thermal stability but showed identical RNA replication activity. Furthermore, we found that the replicase undergoes conversion between these forms due to oxidation, and the Cys-533 residue in the catalytic β subunit and Cys-82 residue in the EF-Tu subunit of the replicase are essential prerequisites for this conversion to occur. These results strongly suggest that the thermal stable replicase contains the intersubunit disulfide bond between these cysteines. The established strategies for isolating and purifying a thermally stable replicase should increase the usefulness of Qβ replicase in various applications, and the data regarding thermal stability obtained in this study may yield insight into the precise mechanism of infection by bacteriophage Qβ.
Collapse
Affiliation(s)
- Norikazu Ichihashi
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Yamadaoka 1-5, Suita, Osaka 565-0871, Japan
| | | | | | | |
Collapse
|
13
|
Urabe H, Ichihashi N, Matsuura T, Hosoda K, Kazuta Y, Kita H, Yomo T. Compartmentalization in a Water-in-Oil Emulsion Repressed the Spontaneous Amplification of RNA by Qβ Replicase. Biochemistry 2010; 49:1809-13. [PMID: 20108973 DOI: 10.1021/bi901805u] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hiroya Urabe
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University
| | - Norikazu Ichihashi
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University
| | - Tomoaki Matsuura
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University
| | - Kazufumi Hosoda
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University
| | - Yasuaki Kazuta
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University
| | - Hiroshi Kita
- Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency (JST)
| | - Tetsuya Yomo
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University
- Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency (JST)
- Graduate School of Frontier Biosciences, Osaka University
| |
Collapse
|