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Greenrod STE, Cazares D, Johnson S, Hector TE, Stevens EJ, MacLean RC, King KC. Warming alters life-history traits and competition in a phage community. Appl Environ Microbiol 2024; 90:e0028624. [PMID: 38624196 PMCID: PMC11107170 DOI: 10.1128/aem.00286-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 03/26/2024] [Indexed: 04/17/2024] Open
Abstract
Host-parasite interactions are highly susceptible to changes in temperature due to mismatches in species thermal responses. In nature, parasites often exist in communities, and responses to temperature are expected to vary between host-parasite pairs. Temperature change thus has consequences for both host-parasite dynamics and parasite-parasite interactions. Here, we investigate the impact of warming (37°C, 40°C, and 42°C) on parasite life-history traits and competition using the opportunistic bacterial pathogen Pseudomonas aeruginosa (host) and a panel of three genetically diverse lytic bacteriophages (parasites). We show that phages vary in their responses to temperature. While 37°C and 40°C did not have a major effect on phage infectivity, infection by two phages was restricted at 42°C. This outcome was attributed to disruption of different phage life-history traits including host attachment and replication inside hosts. Furthermore, we show that temperature mediates competition between phages by altering their competitiveness. These results highlight phage trait variation across thermal regimes with the potential to drive community dynamics. Our results have important implications for eukaryotic viromes and the design of phage cocktail therapies.IMPORTANCEMammalian hosts often elevate their body temperatures through fevers to restrict the growth of bacterial infections. However, the extent to which fever temperatures affect the communities of phages with the ability to parasitize those bacteria remains unclear. In this study, we investigate the impact of warming across a fever temperature range (37°C, 40°C, and 42°C) on phage life-history traits and competition using a bacterium (host) and bacteriophage (parasite) system. We show that phages vary in their responses to temperature due to disruption of different phage life-history traits. Furthermore, we show that temperature can alter phage competitiveness and shape phage-phage competition outcomes. These results suggest that fever temperatures have the potential to restrict phage infectivity and drive phage community dynamics. We discuss implications for the role of temperature in shaping host-parasite interactions more widely.
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Affiliation(s)
| | - Daniel Cazares
- Department of Biology, University of Oxford, Oxford, United Kingdom
| | - Serena Johnson
- Department of Biology, University of Oxford, Oxford, United Kingdom
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Tobias E. Hector
- Department of Biology, University of Oxford, Oxford, United Kingdom
| | - Emily J. Stevens
- Department of Biology, University of Oxford, Oxford, United Kingdom
| | - R. Craig MacLean
- Department of Biology, University of Oxford, Oxford, United Kingdom
| | - Kayla C. King
- Department of Biology, University of Oxford, Oxford, United Kingdom
- Department of Zoology, University of British Columbia, Vancouver, Canada
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
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2
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Daugelavičius R, Daujotaitė G, Bamford DH. Lysis Physiology of Pseudomonas aeruginosa Infected with ssRNA Phage PRR1. Viruses 2024; 16:645. [PMID: 38675985 PMCID: PMC11054506 DOI: 10.3390/v16040645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 04/28/2024] Open
Abstract
The phage PRR1 belongs to the Leviviridae family, a group of ssRNA bacteriophages that infect Gram-negative bacteria. The variety of host cells is determined by the specificity of PRR1 to a pilus encoded by a broad host range of IncP-type plasmids that confer multiple types of antibiotic resistance to the host. Using P. aeruginosa strain PAO1 as a host, we analyzed the PRR1 infection cycle, focusing on cell lysis. PRR1 infection renders P. aeruginosa cells sensitive to lysozyme approximately 20 min before the start of a drop in suspension turbidity. At the same time, infected cells start to accumulate lipophilic anions. The on-line monitoring of the entire infection cycle showed that single-gene-mediated lysis strongly depends on the host cells' physiological state. The blockage of respiration or a reduction in the intracellular ATP concentration during the infection resulted in the inhibition of lysis. The same effect was observed when the synthesis of PRR1 lysis protein was induced in an E. coli expression system. In addition, lysis was strongly dependent on the level of aeration. Dissolved oxygen concentrations sufficient to support cell growth did not ensure efficient lysis, and a coupling between cell lysis initiation and aeration level was observed. However, the duration of the drop in suspension turbidity did not depend on the level of aeration.
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Affiliation(s)
| | - Greta Daujotaitė
- Department of Biochemistry, Vytautas Magnus University, LT-44248 Kaunas, Lithuania;
- Molecular and Integrative Biosciences Research Programme, Department of Biological and Environmental Sciences and Institute of Biotechnology, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Dennis H. Bamford
- Molecular and Integrative Biosciences Research Programme, Department of Biological and Environmental Sciences and Institute of Biotechnology, University of Helsinki, FIN-00014 Helsinki, Finland
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Bull JJ, Wichman HA, Krone SM, Molineux IJ. Controlling Recombination to Evolve Bacteriophages. Cells 2024; 13:585. [PMID: 38607024 PMCID: PMC11011186 DOI: 10.3390/cells13070585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/07/2024] [Accepted: 03/26/2024] [Indexed: 04/13/2024] Open
Abstract
Recombination among different phages sometimes facilitates their ability to grow on new hosts. Protocols to direct the evolution of phage host range, as might be used in the application of phage therapy, would then benefit from including steps to enable recombination. Applying mathematical and computational models, in addition to experiments using phages T3 and T7, we consider ways that a protocol may influence recombination levels. We first address coinfection, which is the first step to enabling recombination. The multiplicity of infection (MOI, the ratio of phage to cell concentration) is insufficient for predicting (co)infection levels. The force of infection (the rate at which cells are infected) is also critical but is more challenging to measure. Using both a high force of infection and high MOI (>1) for the different phages ensures high levels of coinfection. We also apply a four-genetic-locus model to study protocol effects on recombinant levels. Recombinants accumulate over multiple generations of phage growth, less so if one phage outgrows the other. Supplementing the phage pool with the low-fitness phage recovers some of this 'lost' recombination. Overall, fine tuning of phage recombination rates will not be practical with wild phages, but qualitative enhancement can be attained with some basic procedures.
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Affiliation(s)
- James J. Bull
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA;
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, ID 83844, USA;
| | - Holly A. Wichman
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA;
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, ID 83844, USA;
| | - Stephen M. Krone
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, ID 83844, USA;
- Department of Mathematics and Statistical Science, University of Idaho, Moscow, ID 83844, USA
| | - Ian J. Molineux
- Institute for Cell and Molecular Biology, Department of Molecular Biosciences, LaMontagne Center for Infectious Diseases, The University of Texas, Austin, TX 78712, USA;
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Chae D. Phage-host-immune system dynamics in bacteriophage therapy: basic principles and mathematical models. Transl Clin Pharmacol 2023; 31:167-190. [PMID: 38196997 PMCID: PMC10772058 DOI: 10.12793/tcp.2023.31.e17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/17/2023] [Accepted: 10/19/2023] [Indexed: 01/11/2024] Open
Abstract
Phage therapy is progressively being recognized as a viable alternative to conventional antibiotic treatments, particularly in the context of multi-drug resistant bacterial challenges. However, the intricacies of the pharmacokinetics and pharmacodynamics (PKPD) pertaining to phages remain inadequately elucidated. A salient characteristic of phage PKPD is the inherent ability of phages to undergo replication. In this review, I proffer mathematical models that delineate the intricate dynamics encompassing the phage, the host organism, and the immune system. Fundamental tenets associated with proliferative and inundation thresholds are explored, and distinctions between active and passive therapies are accentuated. Furthermore, I present models that aim to illuminate the multifaceted interactions amongst diverse phage strains and bacterial subpopulations, each possessing distinct sensitivities to phages. The synergistic relationship between phages and the immune system is critically examined, demonstrating how the host's immunological function can influence the requisite phage dose for an optimal therapeutic outcome. A profound understanding of the presented modeling methodologies is paramount for researchers in the realms of clinical pharmacology and PKPD modeling interested in phage therapy. Such insights facilitate a more nuanced interpretation of dose-response relationships, enable the selection of potent phages, and aid in the optimization of phage cocktails.
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Affiliation(s)
- Dongwoo Chae
- Department of Pharmacology, Yonsei University College of Medicine, Seoul 03722, Korea
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Smith NM, Nguyen TD, Chin WH, Sanborn JT, de Souza H, Ho BM, Luong T, Roach DR. A mechanism-based pathway toward administering highly active N-phage cocktails. Front Microbiol 2023; 14:1292618. [PMID: 38045026 PMCID: PMC10690594 DOI: 10.3389/fmicb.2023.1292618] [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: 09/11/2023] [Accepted: 10/24/2023] [Indexed: 12/05/2023] Open
Abstract
Bacteriophage (phage) therapy is being explored as a possible response to the antimicrobial resistance public health emergency. Administering a mixture of different phage types as a cocktail is one proposed strategy for therapeutic applications, but the optimal method for formulating phage cocktails remains a major challenge. Each phage strain has complex pharmacokinetic/pharmacodynamic (PK/PD) properties which depend on the nano-scale size, target-mediated, self-dosing nature of each phage strain, and rapid selection of resistant subpopulations. The objective of this study was to explore the pharmacodynamics (PD) of three unique and clinically relevant anti-Pseudomonas phages after simulation of dynamic dosing strategies. The Hollow Fiber Infection Model (HFIM) is an in vitro system that mimics in vivo pharmacokinetics (PK) with high fidelity, providing an opportunity to quantify phage and bacteria concentration profiles over clinical time scales with rich sampling. Exogenous monotherapy-bolus (producing max concentrations of Cmax = 7 log10 PFU/mL) regimens of phages LUZ19, PYO2, and E215 produced Pseudomonas aeruginosa nadirs of 0, 2.14, or 2.99 log10 CFU/mL after 6 h of treatment, respectively. Exogenous combination therapy bolus regimens (LUZ19 + PYO2 or LUZ19 + E215) resulted in bacterial reduction to <2 log10 CFU/mL. In contrast, monotherapy as a continuous infusion (producing a steady-state concentration of Css,avg = 2 log10PFU/mL) was less effective at reducing bacterial densities. Specifically, PYO2 failed to reduce bacterial density. Next, a mechanism-based mathematical model was developed to describe phage pharmacodynamics, phage-phage competition, and phage-dependent adaptive phage resistance. Monte Carlo simulations supported bolus dose regimens, predicting lower bacterial counts with bolus dosing as compared to prolonged phage infusions. Together, in vitro and in silico evaluation of the time course of phage pharmacodynamics will better guide optimal patterns of administration of individual phages as a cocktail.
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Affiliation(s)
- Nicholas M. Smith
- Division of Clinical and Translational Therapeutics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, New York, NY, United States
| | - Thomas D. Nguyen
- Division of Clinical and Translational Therapeutics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, New York, NY, United States
| | - Wai Hoe Chin
- Department of Biology, San Diego State University, San Diego, CA, United States
| | - Jacob T. Sanborn
- Division of Clinical and Translational Therapeutics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, New York, NY, United States
| | - Harriet de Souza
- Division of Clinical and Translational Therapeutics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, New York, NY, United States
| | - Brian M. Ho
- Division of Clinical and Translational Therapeutics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, New York, NY, United States
| | - Tiffany Luong
- Department of Biology, San Diego State University, San Diego, CA, United States
| | - Dwayne R. Roach
- Department of Biology, San Diego State University, San Diego, CA, United States
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Laguna-Castro M, Rodríguez-Moreno A, Llorente E, Lázaro E. The balance between fitness advantages and costs drives adaptation of bacteriophage Qβ to changes in host density at different temperatures. Front Microbiol 2023; 14:1197085. [PMID: 37303783 PMCID: PMC10248866 DOI: 10.3389/fmicb.2023.1197085] [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: 03/30/2023] [Accepted: 05/12/2023] [Indexed: 06/13/2023] Open
Abstract
Introduction Host density is one of the main factors affecting the infective capacity of viruses. When host density is low, it is more difficult for the virus to find a susceptible cell, which increases its probability of being damaged by the physicochemical agents of the environment. Nevertheless, viruses can adapt to variations in host density through different strategies that depend on the particular characteristics of the life cycle of each virus. In a previous work, using the bacteriophage Qβ as an experimental model, we found that when bacterial density was lower than optimal the virus increased its capacity to penetrate into the bacteria through a mutation in the minor capsid protein (A1) that is not described to interact with the cell receptor. Results Here we show that the adaptive pathway followed by Qβ in the face of similar variations in host density depends on environmental temperature. When the value for this parameter is lower than optimal (30°C), the mutation selected is the same as at the optimal temperature (37°C). However, when temperature increases to 43°C, the mutation selected is located in a different protein (A2), which is involved both in the interaction with the cell receptor and in the process of viral progeny release. The new mutation increases the entry of the phage into the bacteria at the three temperatures assayed. However, it also considerably increases the latent period at 30 and 37°C, which is probably the reason why it is not selected at these temperatures. Conclusion The conclusion is that the adaptive strategies followed by bacteriophage Qβ, and probably other viruses, in the face of variations in host density depend not only on their advantages at this selective pressure, but also on the fitness costs that particular mutations may present in function of the rest of environmental parameters that influence viral replication and stability.
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Chen Y, Li W, Shi K, Fang Z, Yang Y, Zhang R. Isolation and characterization of a novel phage belonging to a new genus against Vibrio parahaemolyticus. Virol J 2023; 20:81. [PMID: 37127579 PMCID: PMC10152775 DOI: 10.1186/s12985-023-02036-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Accepted: 04/11/2023] [Indexed: 05/03/2023] Open
Abstract
BACKGROUND Vibrio parahaemolyticus is a major foodborne pathogen that contaminates aquatic products and causes great economic losses to aquaculture. Because of the emergence of multidrug-resistant V. parahaemolyticus strains, bacteriophages are considered promising agents for their biocontrol as an alternative or supplement to antibiotics. In this study, a lytic vibriophage, vB_VpaM_R16F (R16F), infecting V. parahaemolyticus 1.1997T was isolated, characterized and evaluated for its biocontrol potential. METHODS A vibriophage R16F was isolated from sewage from a seafood market with the double-layer agar method. R16F was studied by transmission electron microscopy, host range, sensitivity of phage particles to chloroform, one-step growth curve and lytic activity. The phage genome was sequenced and in-depth characterized, including phylogenetic and taxonomic analysis. RESULTS R16F belongs to the myovirus morphotype and infects V. parahaemolyticus, but not nine other Vibrio spp. As characterized by determining its host range, one-step growth curve, and lytic activity, phage R16F was found to highly effective in lysing host cells with a short latent period (< 10 min) and a small burst size (13 plaque-forming units). R16F has a linear double-stranded DNA with genome size 139,011 bp and a G + C content of 35.21%. Phylogenetic and intergenomic nucleotide sequence similarity analysis revealed that R16F is distinct from currently known vibriophages and belongs to a novel genus. Several genes (e.g., encoding ultraviolet damage endonuclease and endolysin) that may enhance environmental competitiveness were found in the genome of R16F, while no antibiotic resistance- or virulence factor-related gene was detected. CONCLUSIONS In consideration of its biological and genetic properties, this newly discovered phage R16F belongs to a novel genus and may be a potential alternate biocontrol agent.
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Affiliation(s)
- Yubing Chen
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, Fujian, China
- China-ASEAN College of Marine Sciences, Xiamen University Malaysia, Sepang, 43900, Selangor, Malaysia
| | - Wenqing Li
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, Fujian, China
- College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, 361102, Fujian, China
| | - Keming Shi
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, Fujian, China
- College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, 361102, Fujian, China
| | - Zheng Fang
- China-ASEAN College of Marine Sciences, Xiamen University Malaysia, Sepang, 43900, Selangor, Malaysia
| | - Yunlan Yang
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, Fujian, China.
- College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, 361102, Fujian, China.
| | - Rui Zhang
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518061, Guangdong, China.
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8
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Kannoly S, Oken G, Shadan J, Musheyev D, Singh K, Singh A, Dennehy JJ. Single-Cell Approach Reveals Intercellular Heterogeneity in Phage-Producing Capacities. Microbiol Spectr 2023; 11:e0266321. [PMID: 36541779 PMCID: PMC9927085 DOI: 10.1128/spectrum.02663-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Bacteriophage burst size is the average number of phage virions released from infected bacterial cells, and its magnitude depends on the duration of an intracellular progeny accumulation phase. Burst size is often measured at the population level, not the single-cell level, and consequently, statistical moments are not commonly available. In this study, we estimated the bacteriophage lambda (λ) single-cell burst size mean and variance following different intracellular accumulation period durations by employing Escherichia coli lysogens bearing lysis-deficient λ prophages. Single lysogens can be isolated and chemically lysed at desired times following prophage induction to quantify progeny intracellular accumulation within individual cells. Our data showed that λ phage burst size initially increased exponentially with increased lysis time (i.e., period between induction and chemical lysis) and then saturated at longer lysis times. We also demonstrated that cell-to-cell variation, or "noise," in lysis timing did not contribute significantly to burst size noise. The burst size noise remained constant with increasing mean burst size. The most likely explanation for the experimentally observed constant burst size noise was that cell-to-cell differences in burst size originated from intercellular heterogeneity in cellular capacities to produce phages. The mean burst size measured at different lysis times was positively correlated to cell volume, which may determine the cellular phage production capacity. However, experiments controlling for cell size indicated that there are other factors in addition to cell size that determine this cellular capacity. IMPORTANCE Phages produce offspring by hijacking a cell's replicative machinery. Previously, it was noted that the variation in the number of phages produced by single infected cells far exceeded cell size variation. It was hypothesized that this variation is a consequence of variation in the timing of host cell lysis. Here, we show that cell-to-cell variation in lysis timing does not significantly contribute to the burst size variation. We suggest that the constant burst size variation across different host lysis times results from cell-to-cell differences in capacity to produce phages. We found that the mean burst size measured at different lysis times was positively correlated to cell volume, which may determine the cellular phage production capacity. However, experiments controlling for cell size indicated that there are other factors in addition to cell size that determine this cellular capacity.
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Affiliation(s)
- Sherin Kannoly
- Biology Department, Queens College of The City University of New York, New York, New York, USA
| | - Gabriella Oken
- Biology Department, Queens College of The City University of New York, New York, New York, USA
| | - Jonathan Shadan
- Biology Department, Queens College of The City University of New York, New York, New York, USA
| | - David Musheyev
- Biology Department, Queens College of The City University of New York, New York, New York, USA
| | - Kevin Singh
- Biology Department, Queens College of The City University of New York, New York, New York, USA
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware, USA
| | - John J. Dennehy
- Biology Department, Queens College of The City University of New York, New York, New York, USA
- The Graduate Center of The City University of New York, New York, New York, USA
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9
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Maina AN, Mwaura FB, Wagacha JM, Jumba M, Aziz RK, Nour El-Din HT. Phenotypic characterization of phage vB_vcM_Kuja. J Basic Microbiol 2023; 63:481-488. [PMID: 36670071 DOI: 10.1002/jobm.202200635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/07/2022] [Accepted: 01/08/2023] [Indexed: 01/22/2023]
Abstract
Bacteriophage therapy targeting the increasingly resistant Vibrio cholerae is highly needed. Hence, studying the phenotypic behavior of potential phages under different conditions is a prerequisite to delivering the phage in an active infective form. The objective of this study was to characterize phage VP4 (vB_vcM_Kuja), an environmental vibriophage isolated from River Kuja in Migori County, Kenya in 2015. The phenotypic characteristics of the phage were determined using a one-step growth curve, restriction digestion profile, pH, and temperature stability tests. The results revealed that the phage is stable through a wide range of temperatures (20-50°C) and maintains its plaque-forming ability at pH ranging from 6 to 12. The one-step growth curve showed a latent period falling between 40 and 60 min, while burst size ranged from 23 to 30 plaque-forming units/10 µl at the same host strain. The restriction digestion pattern using EcoRI, SalI, HindIII, and XhoI enzymes showed that HindIII could cut the phage genome. The phage DNA could not be restricted by the other three enzymes. The findings of this study can be used in future studies to determine phage-host interactions.
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Affiliation(s)
- Alice N Maina
- Department of Biology, University of Nairobi, Nairobi, Kenya
| | | | - John M Wagacha
- Department of Biology, University of Nairobi, Nairobi, Kenya
| | - Miriam Jumba
- Department of Biology, University of Nairobi, Nairobi, Kenya
| | - Ramy K Aziz
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt.,Microbiology and Immunology Research Program, Children's Cancer Hospital Egypt 57357, Cairo, Egypt
| | - Hanzada T Nour El-Din
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
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10
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Lu YT, Ma Y, Wong CW, Wang S. Characterization and application of bacteriophages for the biocontrol of Shiga-toxin producing Escherichia coli in Romaine lettuce. Food Control 2022. [DOI: 10.1016/j.foodcont.2022.109109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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11
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Maidanik I, Kirzner S, Pekarski I, Arsenieff L, Tahan R, Carlson MCG, Shitrit D, Baran N, Goldin S, Weitz JS, Lindell D. Cyanophages from a less virulent clade dominate over their sister clade in global oceans. THE ISME JOURNAL 2022; 16:2169-2180. [PMID: 35726021 PMCID: PMC9381782 DOI: 10.1038/s41396-022-01259-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 05/23/2022] [Accepted: 05/27/2022] [Indexed: 11/18/2022]
Abstract
Environmental virus communities are highly diverse. However, the infection physiology underlying the evolution of diverse phage lineages and their ecological consequences are largely unknown. T7-like cyanophages are abundant in nature and infect the marine unicellular cyanobacteria, Synechococcus and Prochlorococcus, important primary producers in the oceans. Viruses belonging to this genus are divided into two distinct phylogenetic clades: clade A and clade B. These viruses have narrow host-ranges with clade A phages primarily infecting Synechococcus genotypes, while clade B phages are more diverse and can infect either Synechococcus or Prochlorococcus genotypes. Here we investigated infection properties (life history traits) and environmental abundances of these two clades of T7-like cyanophages. We show that clade A cyanophages have more rapid infection dynamics, larger burst sizes and greater virulence than clade B cyanophages. However, clade B cyanophages were at least 10-fold more abundant in all seasons, and infected more cyanobacteria, than clade A cyanophages in the Red Sea. Models predicted that steady-state cyanophage abundances, infection frequency, and virus-induced mortality, peak at intermediate virulence values. Our findings indicate that differences in infection properties are reflected in virus phylogeny at the clade level. They further indicate that infection properties, together with differences in subclade diversity and host repertoire, have important ecological consequences with the less aggressive, more diverse virus clade having greater ecological impacts.
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12
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Farquharson EL, Nugen SR. Enterobacteria Phage Ac3's Genome Annotation and Host Range Analysis Against the ECOR Reference Library. PHAGE (NEW ROCHELLE, N.Y.) 2022; 3:165-170. [PMID: 36199530 PMCID: PMC9527048 DOI: 10.1089/phage.2022.0008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Host range analyses and genome sequencing/annotation of bacteriophage isolates allow more effective development of tools for applications in medicine, agriculture, and the environment and expand our understanding of phage biology. Here we present the complete sequence of phage Ac3's assembled and annotated genome (accession OK040907). Originally referred to simply as "3," Ac3 has previously been described as a T4-like bacteriophage belonging to the Myoviridae family in the Caudovirales order of tailed bacteriophages. Using a combination of spot tests and full plate plaque assays, Ac3's permissive and adsorptive host range were evaluated against the ECOR Reference Library; a panel of 72 Escherichia coli isolates meant to represent the diversity of E. coli. Spot assays revealed that Ac3 could adsorb to 43 of the 72 strains (59.7%), whereas plaque assays demonstrated Ac3's ability to complete replication within 27 of the 72 strains (37.5%). By overlaying spot test and plaque assay results, 16 of the 45 nonpermissive ECOR strains (35.5%) were highlighted as being able to support Ac3's adsorption and tail contraction, but not its replication. Further characterization of Ac3 is still needed, however, the study presented here provides a solid starting point for future research.
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Affiliation(s)
| | - Sam R. Nugen
- Department of Food Science, Cornell University, Ithaca, New York, USA
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13
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Minimizing Foaming and Bulking in Activated Sludge with Bacteriophage Treatment: A Review of Mathematical Modeling. Processes (Basel) 2022. [DOI: 10.3390/pr10081600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The interest in the ability of phages to control bacterial populations has extended from medical applications into the fields of agriculture, aquaculture, and the food industry. In particular, several authors have proposed using bacteriophages as an alternative method to control foaming and bulking in wastewater treatment. This strategy has shown successful results at the laboratory scale. However, this technology is still in development, and there are several challenges to overcome before bacteriophages can be widely used to control foaming and bulking in pilot or larger-scale treatment plants. Several models of the infection mechanisms in individual bacteria–phage pairs have been reported, i.e., for controlled systems with only one bacterium species in the presence of one phage species. However, activated sludge treatment systems largely differ from this situation, which opens a large horizon for future research. Mathematical models will play a key role in this development process, and this review offers an overview of the proposed models: their applications, potential, and challenges. A particular focus is placed on the model properties, such as parameter identifiability and states’ observability, which are essential for process prediction, monitoring, or dynamic optimization.
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14
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An Optimal Lysis Time Maximizes Bacteriophage Fitness in Quasi-Continuous Culture. mBio 2022; 13:e0359321. [PMID: 35467417 PMCID: PMC9239172 DOI: 10.1128/mbio.03593-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Optimality models have a checkered history in evolutionary biology. While optimality models have been successful in providing valuable insight into the evolution of a wide variety of biological traits, a common objection is that optimality models are overly simplistic and ignore organismal genetics. We revisit evolutionary optimization in the context of a major bacteriophage life history trait, lysis time. Lysis time refers to the period spanning phage infection of a host cell and its lysis, whereupon phage progenies are released. Lysis time, therefore, directly determines phage fecundity assuming progeny assembly does not exhaust host resources prior to lysis. Noting that previous tests of lysis time optimality rely on batch culture, we implemented a quasi-continuous culture system to observe productivity of a panel of isogenic phage λ genotypes differing in lysis time. We report that under our experimental conditions, λ phage productivity is maximized around optimal lysis times ranging from 60 to 100 min, and λ wildtype strain falls within this range. It would appear that natural selection on phage λ lysis time uncovered a set of genetic solutions that optimized progeny production in its ecological milieu relative to alternative genotypes. We discuss this finding in light of recent results that lysis time variation is also minimized in the strains with lysis times closer to the λ wild-type strain. IMPORTANCE Optimality theory presents the idea that natural selection acts on organismal traits to produce genotypes that maximize organismal survival and reproduction. As such, optimality theory is a valuable tool in guiding our understanding of the genetic constraints and tradeoffs organisms experience as their genotypes are selected to produce optimal solutions to biological problems. However, optimality theory is often critiqued as being overly simplistic and ignoring the roles of chance and history in the evolution of organismal traits. We show here that the wild-type genotype of a popular laboratory model organism, the bacteriophage λ, produces a phenotype for a major life history trait, lysis time, that maximizes the reproductive success of bearers of that genotype relative to other possible genotypes. This result demonstrates, as is rarely shown experimentally, that natural selection can achieve optimal solutions to ecological challenges.
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15
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Abedon ST. Further Considerations on How to Improve Phage Therapy Experimentation, Practice, and Reporting: Pharmacodynamics Perspectives. PHAGE (NEW ROCHELLE, N.Y.) 2022; 3:98-111. [PMID: 36148139 PMCID: PMC9436263 DOI: 10.1089/phage.2022.0019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Phage therapy uses bacterial viruses (bacteriophages) to infect and kill targeted pathogens. Approximately one decade ago, I started publishing on how possibly to improve upon phage therapy experimentation, practice, and reporting. Here, I gather and expand upon some of those suggestions. The issues emphasized are (1) that using ratios of antibacterial agents to bacteria is not how dosing is accomplished in the real world, (2) that it can be helpful to not ignore Poisson distributions as a means of either anticipating or characterizing phage therapy success, and (3) how to calculate a concept of 'inundative phage densities.' Together, these are issues of phage therapy pharmacodynamics, meaning they are ways of thinking about the potential for phage therapy treatments to be efficacious mostly independent of the details of delivery of phages to targeted bacteria. Much emphasis is placed on working with Poisson distributions to better align phage therapy with other antimicrobial treatments.
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Affiliation(s)
- Stephen T. Abedon
- Department of Microbiology, The Ohio State University, Mansfield, Ohio, USA
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16
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Huang C, Feng C, Liu X, Zhao R, Wang Z, Xi H, Ou H, Han W, Guo Z, Gu J, Zhang L. The Bacteriophage vB_CbrM_HP1 Protects Crucian Carp Against Citrobacter braakii Infection. Front Vet Sci 2022; 9:888561. [PMID: 35601403 PMCID: PMC9120918 DOI: 10.3389/fvets.2022.888561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
Citrobacter braakii is an opportunistic pathogen that induces aquatic infections in fish and turtles. In this study, a bacteriophage that infects C. braakii, named vB_CbrM_HP1, was isolated from sewage. This phage belongs to Myoviridae family, Ounavirinae subfamily, Mooglevirus genus. We also used the phage to treat crucian carp infection caused by C. braakii for the first time. vB_CbrM_HP1 was relatively stable at temperatures ranging from 4 to 60°C and pH values ranging from 3 to 11 but float slightly. When the multiplicities of infection (MOI) was 0.0001, the titer reached a maximum of 4.20 × 1010 PFU/ml. As revealed from the results of whole genomic sequence analysis, the total length of vB_CbrM_HP1 was 89335 bp, encoding 135 ORFs, 9 of which were <75% similar to the known sequences in NCBI. The phage vB_CbrM_HP1 showed a highly efficient bactericidal effect against C. braakii both in vitro and in vivo. In vitro, vB_CbrM_HP1 was capable of effectively killing bacteria (the colony count decreased by 4.7 log units at 5 h). In vivo, administration of vB_CbrM_HP1 (1 × 109 PFU) effectively protected crucian carp against fatal infection caused by C. braakii. Phage treatment reduced the levels of inflammatory factors. All these results demonstrated the potential of vB_CbrM_HP1 as an alternative treatment strategy for infections caused by C. braakii.
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Affiliation(s)
- Chunzheng Huang
- State Key Laboratory for Zoonotic Diseases, Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Chao Feng
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
| | - Xiao Liu
- State Key Laboratory for Zoonotic Diseases, Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Rihong Zhao
- State Key Laboratory for Zoonotic Diseases, Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Zijing Wang
- State Key Laboratory for Zoonotic Diseases, Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Hengyu Xi
- State Key Laboratory for Zoonotic Diseases, Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Hongda Ou
- State Key Laboratory for Zoonotic Diseases, Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Wenyu Han
- State Key Laboratory for Zoonotic Diseases, Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Zhimin Guo
- Department of Clinical Laboratory, The First Hospital of Jilin University, Changchun, China
- *Correspondence: Zhimin Guo
| | - Jingmin Gu
- State Key Laboratory for Zoonotic Diseases, Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
- Jingmin Gu
| | - Lei Zhang
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
- Lei Zhang
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17
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Phenotypic and molecular characterization of two lytic bacteriophages against multidrug resistant Pseudomonas aeruginosa. Saudi J Biol Sci 2022. [DOI: 10.1016/j.sjbs.2022.02.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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18
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DeLong JP, Al-Sammak MA, Al-Ameeli ZT, Dunigan DD, Edwards KF, Fuhrmann JJ, Gleghorn JP, Li H, Haramoto K, Harrison AO, Marston MF, Moore RM, Polson SW, Ferrell BD, Salsbery ME, Schvarcz CR, Shirazi J, Steward GF, Van Etten JL, Wommack KE. Towards an integrative view of virus phenotypes. Nat Rev Microbiol 2021; 20:83-94. [PMID: 34522049 DOI: 10.1038/s41579-021-00612-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2021] [Indexed: 12/25/2022]
Abstract
Understanding how phenotypes emerge from genotypes is a foundational goal in biology. As challenging as this task is when considering cellular life, it is further complicated in the case of viruses. During replication, a virus as a discrete entity (the virion) disappears and manifests itself as a metabolic amalgam between the virus and the host (the virocell). Identifying traits that unambiguously constitute a virus's phenotype is straightforward for the virion, less so for the virocell. Here, we present a framework for categorizing virus phenotypes that encompasses both virion and virocell stages and considers functional and performance traits of viruses in the context of fitness. Such an integrated view of virus phenotype is necessary for comprehensive interpretation of viral genome sequences and will advance our understanding of viral evolution and ecology.
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Affiliation(s)
- John P DeLong
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA.
| | - Maitham A Al-Sammak
- Tropical Biological Research Unit, College of Science, University of Baghdad, Baghdad, Iraq.,Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Zeina T Al-Ameeli
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE, USA.,Medical Technical Institutes, Middle Technical University, Baghdad, Iraq
| | - David D Dunigan
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE, USA.,Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Kyle F Edwards
- Department of Oceanography, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Jeffry J Fuhrmann
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, USA.,Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Jason P Gleghorn
- Department of Biological Sciences, University of Delaware, Newark, DE, USA.,Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - Hanqun Li
- Department of Biological Sciences, University of Delaware, Newark, DE, USA.,Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA
| | - Kona Haramoto
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, USA.,Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA
| | - Amelia O Harrison
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, USA.,Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA
| | - Marcia F Marston
- Department of Biology and Marine Biology, Roger Williams University, Bristol, RI, USA
| | - Ryan M Moore
- Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.,Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, USA
| | - Shawn W Polson
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, USA.,Department of Biological Sciences, University of Delaware, Newark, DE, USA.,Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.,Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, USA
| | - Barbra D Ferrell
- Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.,Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, USA
| | - Miranda E Salsbery
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | | | - Jasmine Shirazi
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - Grieg F Steward
- Department of Oceanography, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - James L Van Etten
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE, USA.,Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - K Eric Wommack
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, USA. .,Department of Biological Sciences, University of Delaware, Newark, DE, USA. .,Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.
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19
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Silva J, Dias R, Junior JI, Marcelino M, Silva M, Carmo A, Sousa M, Silva C, de Paula S. A Rapid Method for Performing a Multivariate Optimization of Phage Production Using the RCCD Approach. Pathogens 2021; 10:1100. [PMID: 34578135 PMCID: PMC8468216 DOI: 10.3390/pathogens10091100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 01/15/2023] Open
Abstract
Bacteriophages can be used in various applications, from the classical approach as substitutes for antibiotics (phage therapy) to new biotechnological uses, i.e., as a protein delivery vehicle, a diagnostic tool for specific strains of bacteria (phage typing), or environmental bioremediation. The demand for bacteriophage production increases daily, and studies that improve these production processes are necessary. This study evaluated the production of a T4-like bacteriophage vB_EcoM-UFV09 (an E. coli-infecting phage with high potential for reducing environmental biofilms) in seven types of culture media (Luria-Bertani broth and the M9 minimal medium with six different carbon sources) employing four cultivation variables (temperature, incubation time, agitation, and multiplicity of infection). For this purpose, the rotatable central composite design (RCCD) methodology was used, combining and comparing all parameters to determine the ideal conditions for starting to scale up the production process. We used the RCCD to set up the experimental design by combining the cultivation parameters in a specific and systematic way. Despite the high number of conditions evaluated, the results showed that when specific conditions were utilized, viral production was effective even when using a minimal medium, such as M9/glucose, which is less expensive and can significantly reduce costs during large-scale phage production.
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Affiliation(s)
- Jessica Silva
- Laboratory of Molecular Immunovirology, Department of General Biology, Federal University of Viçosa, Viçosa, Minas Gerais 36570-900, Brazil; (J.S.); (R.D.); (M.M.); (M.S.); (A.C.); (M.S.)
| | - Roberto Dias
- Laboratory of Molecular Immunovirology, Department of General Biology, Federal University of Viçosa, Viçosa, Minas Gerais 36570-900, Brazil; (J.S.); (R.D.); (M.M.); (M.S.); (A.C.); (M.S.)
| | - José Ivo Junior
- Department of Statistics, Federal University of Viçosa, Viçosa, Minas Gerais 36570-900, Brazil;
| | - Maraísa Marcelino
- Laboratory of Molecular Immunovirology, Department of General Biology, Federal University of Viçosa, Viçosa, Minas Gerais 36570-900, Brazil; (J.S.); (R.D.); (M.M.); (M.S.); (A.C.); (M.S.)
| | - Mirelly Silva
- Laboratory of Molecular Immunovirology, Department of General Biology, Federal University of Viçosa, Viçosa, Minas Gerais 36570-900, Brazil; (J.S.); (R.D.); (M.M.); (M.S.); (A.C.); (M.S.)
| | - Adriele Carmo
- Laboratory of Molecular Immunovirology, Department of General Biology, Federal University of Viçosa, Viçosa, Minas Gerais 36570-900, Brazil; (J.S.); (R.D.); (M.M.); (M.S.); (A.C.); (M.S.)
| | - Maira Sousa
- Laboratory of Molecular Immunovirology, Department of General Biology, Federal University of Viçosa, Viçosa, Minas Gerais 36570-900, Brazil; (J.S.); (R.D.); (M.M.); (M.S.); (A.C.); (M.S.)
- Leopoldo Américo Miguez de Mello Research Center (CENPES), Petrobras, Rio de Janeiro 20230-010, Brazil
| | - Cynthia Silva
- Department of Microbiology, Federal University of Viçosa, Viçosa, Minas Gerais 36570-900, Brazil;
| | - Sergio de Paula
- Laboratory of Molecular Immunovirology, Department of General Biology, Federal University of Viçosa, Viçosa, Minas Gerais 36570-900, Brazil; (J.S.); (R.D.); (M.M.); (M.S.); (A.C.); (M.S.)
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20
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Xu H, Bao X, Hong W, Wang A, Wang K, Dong H, Hou J, Govinden R, Deng B, Chenia HY. Biological Characterization and Evolution of Bacteriophage T7-△holin During the Serial Passage Process. Front Microbiol 2021; 12:705310. [PMID: 34408735 PMCID: PMC8365609 DOI: 10.3389/fmicb.2021.705310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 06/28/2021] [Indexed: 11/21/2022] Open
Abstract
Bacteriophage T7 gene 17.5 coding for the only known holin is one of the components of its lysis system, but the holin activity in T7 is more complex than a single gene, and evidence points to the existence of additional T7 genes with holin activity. In this study, a T7 phage with a gene 17.5 deletion (T7-△holin) was rescued and its biological characteristics and effect on cell lysis were determined. Furthermore, the genomic evolution of mutant phage T7-△holin during serial passage was assessed by whole-genome sequencing analysis. It was observed that deletion of gene 17.5 from phage T7 delays lysis time and enlarges the phage burst size; however, this biological characteristic recovered to normal lysis levels during serial passage. Scanning electron microscopy showed that the two opposite ends of E. coli BL21 cells swell post-T7-△holin infection rather than drilling holes on cell membrane when compared with T7 wild-type infection. No visible progeny phage particle accumulation was observed inside the E. coli BL21 cells by transmission electron microscopy. Following serial passage of T7-△holin from the 1st to 20th generations, the mRNA levels of gene 3.5 and gene 19.5 were upregulated and several mutation sites were discovered, especially two missense mutations in gene 19.5, which indicate a potential contribution to the evolution of the T7-△holin. Although the burst size of T7-△holin increased, high titer cultivation of T7-△holin was not achieved by optimizing the culture process. Accordingly, these results suggest that gene 19.5 is a potential lysis-related component that needs to be studied further and that the T7-△holin strain with its gene 17.5 deletion is not adequate to establish the high-titer phage cultivation process.
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Affiliation(s)
- Hai Xu
- Jiangsu Key Laboratory for High-Tech Research and Development of Veterinary Biopharmaceuticals, Jiangsu Agri-Animal Husbandry Vocational College, Taizhou, China.,Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Science, Nanjing, China.,School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Durban, South Africa
| | - Xi Bao
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Science, Nanjing, China
| | - Weiming Hong
- Jiangsu Key Laboratory for High-Tech Research and Development of Veterinary Biopharmaceuticals, Jiangsu Agri-Animal Husbandry Vocational College, Taizhou, China
| | - Anping Wang
- Jiangsu Key Laboratory for High-Tech Research and Development of Veterinary Biopharmaceuticals, Jiangsu Agri-Animal Husbandry Vocational College, Taizhou, China
| | - Kaimin Wang
- Animal, Plant and Food Test Center of Nanjing Customs, Nanjing, China
| | - Hongyan Dong
- Jiangsu Key Laboratory for High-Tech Research and Development of Veterinary Biopharmaceuticals, Jiangsu Agri-Animal Husbandry Vocational College, Taizhou, China
| | - Jibo Hou
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Science, Nanjing, China
| | - Roshini Govinden
- School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Durban, South Africa
| | - Bihua Deng
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Science, Nanjing, China.,Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Hafizah Y Chenia
- School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Durban, South Africa
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21
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Zhang Y, Liao YT, Salvador A, Lavenburg VM, Wu VCH. Characterization of Two New Shiga Toxin-Producing Escherichia coli O103-Infecting Phages Isolated from an Organic Farm. Microorganisms 2021; 9:microorganisms9071527. [PMID: 34361962 PMCID: PMC8303462 DOI: 10.3390/microorganisms9071527] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/12/2021] [Accepted: 07/12/2021] [Indexed: 01/21/2023] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) O103 strains have been recently attributed to various foodborne outbreaks in the United States. Due to the emergence of antibiotic-resistant strains, lytic phages are considered as alternative biocontrol agents. This study was to biologically and genomically characterize two STEC O103-infecting bacteriophages, vB_EcoP-Ro103C3lw (or Ro103C3lw) and vB_EcoM-Pr103Blw (or Pr103Blw), isolated from an organic farm. Based on genomic and morphological analyses, phages Ro103C3lw and Pr103Blw belonged to Autographiviridae and Myoviridae families, respectively. Ro103C3lw contained a 39,389-bp double-stranded DNA and encoded a unique tail fiber with depolymerase activity, resulting in huge plaques. Pr103Blw had an 88,421-bp double-stranded DNA with 26 predicted tRNAs associated with the enhancement of the phage fitness. Within each phage genome, no virulence, antibiotic-resistant, and lysogenic genes were detected. Additionally, Ro103C3lw had a short latent period (2 min) and a narrow host range, infecting only STEC O103 strains. By contrast, Pr103Blw had a large burst size (152 PFU/CFU) and a broad host range against STEC O103, O26, O111, O157:H7, and Salmonella Javiana strains. Furthermore, both phages showed strong antimicrobial activities against STEC O103:H2 strains. The findings provide valuable insight into these two phages’ genomic features with the potential antimicrobial activities against STEC O103.
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22
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Singhal S, Turner PE. Effects of historical co-infection on host shift abilities of exploitative and competitive viruses. Evolution 2021; 75:1878-1888. [PMID: 33969482 DOI: 10.1111/evo.14263] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 04/03/2021] [Accepted: 04/16/2021] [Indexed: 12/29/2022]
Abstract
Rapid evolution contributes to frequent emergence of RNA viral pathogens on novel hosts. However, accurately predicting which viral genotypes will emerge has been elusive. Prior work with lytic RNA bacteriophage ɸ6 (family Cystoviridae) suggested that evolution under low multiplicity of infection (MOI; proportion of viruses to susceptible cells) selected for greater host exploitation, while evolution under high MOI selected for better intracellular competition against co-infecting viruses. We predicted that phage genotypes that had experienced 300 generations of low MOI ecological history would be relatively advantaged in initial growth on two novel hosts. We inferred viral growth through changes in host population density, specifically by analyzing five attributes of growth curves of infected bacteria. Despite equivalent growth of evolved viruses on the original host, low MOI evolved clones were generally advantaged relative to high MOI clones in exploiting novel hosts. However, the specific attributes of growth curves that supported their advantage differed by host, indicating interactions between both viral and host genotype. Although there will be host specificity in viral growth, we suggest based on infectivity differences of viruses from high versus low MOI histories that prior MOI selection can later affect emergence potential.
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Affiliation(s)
- Sonia Singhal
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, 06520, USA.,BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, Michigan, 48824, USA.,Current affiliation: Department of Biological Sciences, San José Sate University, San José, California, 95192, USA
| | - Paul E Turner
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, 06520, USA.,BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, Michigan, 48824, USA.,Graduate Program in Microbiology, Yale School of Medicine, New Haven, Connecticut, 06520, USA
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23
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Yi Y, Abdelhamid AG, Xu Y, Yousef AE. Characterization of broad-host lytic Salmonella phages isolated from livestock farms and application against Salmonella Enteritidis in liquid whole egg. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2021.111269] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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24
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Choua M, Heath MR, Bonachela JA. Evolutionarily Stable Coevolution Between a Plastic Lytic Virus and Its Microbial Host. Front Microbiol 2021; 12:637490. [PMID: 34093461 PMCID: PMC8172972 DOI: 10.3389/fmicb.2021.637490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 04/09/2021] [Indexed: 01/21/2023] Open
Abstract
Hosts influence and are influenced by viral replication. Cell size, for example, is a fundamental trait for microbial hosts that can not only alter the probability of viral adsorption, but also constrain the host physiological processes that the virus relies on to replicate. This intrinsic connection can affect the fitness of both host and virus, and therefore their mutual evolution. Here, we study the coevolution of bacterial hosts and their viruses by considering the dependence of viral performance on the host physiological state (viral plasticity). To this end, we modified a standard host-lytic phage model to include viral plasticity, and compared the coevolutionary strategies emerging under different scenarios, including cases in which only the virus or the host evolve. For all cases, we also obtained the evolutionary prediction of the traditional version of the model, which assumes a non-plastic virus. Our results reveal that the presence of the virus leads to an increase in host size and growth rate in the long term, which benefits both interacting populations. Our results also show that viral plasticity and evolution influence the classic host quality-quantity trade-off. Poor nutrient environments lead to abundant low-quality hosts, which tends to increase viral infection time. Conversely, richer nutrient environments lead to fewer but high-quality hosts, which decrease viral infection time. Our results can contribute to advancing our understanding of the microbial response to changing environments. For instance, both cell size and viral-induced mortality are essential factors that determine the structure and dynamics of the marine microbial community, and therefore our study can improve predictions of how marine ecosystems respond to environmental change. Our study can also help devise more reliable strategies to use phage to, for example, fight bacterial infections.
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Affiliation(s)
- Melinda Choua
- Marine Population Modeling Group, Department of Mathematics and Statistics, University of Strathclyde, Scotland, United Kingdom
| | - Michael R Heath
- Marine Population Modeling Group, Department of Mathematics and Statistics, University of Strathclyde, Scotland, United Kingdom
| | - Juan A Bonachela
- Department of Ecology, Evolution and Natural Resources, Rutgers University, New Brunswick, NJ, United States
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25
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João J, Lampreia J, Prazeres DMF, Azevedo AM. Manufacturing of bacteriophages for therapeutic applications. Biotechnol Adv 2021; 49:107758. [PMID: 33895333 DOI: 10.1016/j.biotechadv.2021.107758] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 03/14/2021] [Accepted: 04/20/2021] [Indexed: 12/21/2022]
Abstract
Bacteriophages, or simply phages, are the most abundant biological entities on Earth. One of the most interesting characteristics of these viruses, which infect and use bacteria as their host organisms, is their high level of specificity. Since their discovery, phages became a tool for the comprehension of basic molecular biology and originated applications in a variety of areas such as agriculture, biotechnology, food safety, veterinary, pollution remediation and wastewater treatment. In particular, phages offer a solution to one of the major problems in public health nowadays, i.e. the emergence of multidrug-resistant bacteria. In these situations, the use of virulent phages as therapeutic agents offers an alternative to the classic, antibiotic-based strategies. The development of phage therapies should be accompanied by the improvement of phage biomanufacturing processes, both at laboratory and industrial scales. In this review, we first present some historical and general aspects related with the discovery, usage and biology of phages and provide a brief overview of the most relevant phage therapy applications. Then, we showcase current processes used for the production and purification of phages and future alternatives in development. On the production side, key factors such as the bacterial physiological state, the conditions of phage infection and the operation parameters are described alongside with the different operation modes, from batch to semi-continuous and continuous. Traditional purification methods used in the initial phage isolation steps are then described followed by the presentation of current state-of-the-art purification approaches. Continuous purification of phages is finally presented as a future biomanufacturing trend.
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Affiliation(s)
- Jorge João
- iBB - Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisbon, Portugal.
| | - João Lampreia
- iBB - Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisbon, Portugal.
| | - Duarte Miguel F Prazeres
- iBB - Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisbon, Portugal.
| | - Ana M Azevedo
- iBB - Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisbon, Portugal.
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Wong S, Alattas H, Slavcev RA. A snapshot of the λ T4rII exclusion (Rex) phenotype in Escherichia coli. Curr Genet 2021; 67:739-745. [PMID: 33877398 DOI: 10.1007/s00294-021-01183-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 03/20/2021] [Accepted: 03/25/2021] [Indexed: 10/21/2022]
Abstract
The lambda (λ) T4rII exclusion (Rex) phenotype is defined as the inability of T4rII to propagate in Escherichia coli lysogenized by bacteriophage λ. The Rex system requires the presence of two lambda immunity genes, rexA and rexB, to exclude T4 (rIIA-rIIB) from plating on a lawn of E. coli λ lysogens. The onset of the Rex phenotype by T4rII infection imparts a harsh cellular environment that prevents T4rII superinfection while killing the majority of the cell population. Since the discovery of this powerful exclusion system in 1955 by Seymour Benzer, few mechanistic models have been proposed to explain the process of Rex activation and the physiological manifestations associated with Rex onset. For the first time, key host proteins have recently been linked to Rex, including σE, σS, TolA, and other membrane proteins. Together with the known Rex system components, the RII proteins of bacteriophage T4 and the Rex proteins from bacteriophage λ, we are closer than ever to solving the mystery that has eluded investigators for over six decades. Here, we review the fundamental Rex components in light of this new knowledge.
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Affiliation(s)
- Shirley Wong
- School of Pharmacy, University of Waterloo, ON, N2L 3G1, Canada
| | - Hibah Alattas
- School of Pharmacy, University of Waterloo, ON, N2L 3G1, Canada.
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27
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Abstract
Most phages of Gram-negative hosts encode spanins for disruption of the outer membrane, the last step in host lysis. However, bioinformatic analysis indicates that ∼15% of these phages lack a spanin gene, suggesting they have an alternate way of disrupting the OM. Here, we show that the T7-like coliphage phiKT causes the explosive cell lysis associated with spanin activity despite not encoding spanins. A putative lysis cassette cloned from the phiKT late gene region includes the hypothetical novel gene 28 located between the holin and endolysin genes and supports inducible lysis in E. coli K-12. Moreover, induction of an isogenic construct lacking gene 28 resulted in divalent cation-stabilized spherical cells rather than lysis, implicating gp28 in OM disruption. Additionally, gp28 was shown to complement the lysis defect of a spanin-null λ lysogen. Gene 28 encodes a 56-amino acid cationic protein with predicted amphipathic helical structure and is membrane-associated after lysis. Urea and KCl washes did not release gp28 from the particulate, suggesting a strong hydrophobic membrane interaction. Fluorescence microscopy supports membrane localization of the gp28 protein prior to lysis. Gp28 is similar in size, charge, predicted fold, and membrane association to the human cathelicidin antimicrobial peptide LL-37. Synthesized gp28 behaved similar to LL-37 in standard assays mixing peptide and cells to measure bactericidal and inhibitory effects. Taken together, these results indicate that phiKT gp28 is a phage-encoded cationic antimicrobial peptide that disrupts bacterial outer membranes during host lysis and thus establishes a new class of phage lysis proteins, the disruptins. Significance We provide evidence that phiKT produces an antimicrobial peptide for outer membrane disruption during lysis. This protein, designated as a disruptin, is a new paradigm for phage lysis and has no similarities to other known lysis genes. Although many mechanisms have been proposed for the function of antimicrobial peptides, there is no consensus on the molecular basis of membrane disruption. Additionally, there is no established genetic system to support such studies. Therefore, the phiKT disruptin may represent the first genetically tractable antimicrobial peptide, facilitating mechanistic analyses.
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28
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Lord JS, Bonsall MB. The evolutionary dynamics of viruses: virion release strategies, time delays and fitness minima. Virus Evol 2021; 7:veab039. [PMID: 34221452 PMCID: PMC8242231 DOI: 10.1093/ve/veab039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Viruses exhibit a diverse array of strategies for infecting host cells and for virion release after replication. Cell exit strategies generally involve either budding from the cell membrane or killing the host cell. The conditions under which either is at a selective advantage is a key question in the evolutionary theory of viruses, with the outcome having potentially important impacts on the course of infection and pathogenicity. Although a plethora of external factors will influence the fitness of either strategy; here, we focus just on the effects of the physical properties of the system. We develop theoretical approaches to assess the effects of the time delays between initial infection and virion release. We show that the length of the delay before apoptosis is an important trait in virus evolutionary dynamics. Our results show that for a fixed time to apoptosis, intermediate delays lead to virus fitness that is lower than short times to apoptosis - leading to an apoptotic strategy - and long times to apoptosis - leading to a budding strategy at the between-cell level. At fitness minima, selection is expected to be disruptive and the potential for adaptive radiation in virus strategies is feasible. Hence, the physical properties of the system are sufficient to explain the existence of both budding and virus-induced apoptosis. The fitness functions presented here provide a formal basis for further work focusing on the evolutionary implications of trade-offs between time delays, intracellular replication and resulting mutation rates.
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Affiliation(s)
- Jennifer S Lord
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Michael B Bonsall
- Mathematical Ecology Research Group, Department of Zoology, University of Oxford, Oxford OX1 3SZ, UK
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29
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Arya S, Todman H, Baker M, Hooton S, Millard A, Kreft JU, Hobman JL, Stekel DJ. A generalised model for generalised transduction: the importance of co-evolution and stochasticity in phage mediated antimicrobial resistance transfer. FEMS Microbiol Ecol 2020; 96:5850753. [PMID: 32490523 DOI: 10.1093/femsec/fiaa100] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 06/02/2020] [Indexed: 01/21/2023] Open
Abstract
Antimicrobial resistance is a major global challenge. Of particular concern are mobilizable elements that can transfer resistance genes between bacteria, leading to pathogens with new combinations of resistance. To date, mathematical models have largely focussed on transfer of resistance by plasmids, with fewer studies on transfer by bacteriophages. We aim to understand how best to model transfer of resistance by transduction by lytic phages. We show that models of lytic bacteriophage infection with empirically derived realistic phage parameters lead to low numbers of bacteria, which, in low population or localised environments, lead to extinction of bacteria and phage. Models that include antagonistic co-evolution of phage and bacteria produce more realistic results. Furthermore, because of these low numbers, stochastic dynamics are shown to be important, especially to spread of resistance. When resistance is introduced, resistance can sometimes be fixed, and at other times die out, with the probability of each outcome sensitive to bacterial and phage parameters. Specifically, that outcome most strongly depends on the baseline death rate of bacteria, with phage-mediated spread favoured in benign environments with low mortality over more hostile environments. We conclude that larger-scale models should consider spatial compartmentalisation and heterogeneous microenviroments, while encompassing stochasticity and co-evolution.
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Affiliation(s)
- Sankalp Arya
- Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Henry Todman
- School of Mathematical Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Michelle Baker
- Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK.,School of Mathematical Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Steven Hooton
- Division of Food Science, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Andrew Millard
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Jan-Ulrich Kreft
- School of Biosciences & Institute of Microbiology and Infection & Centre for Computational Biology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Jon L Hobman
- Division of Food Science, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Dov J Stekel
- Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
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30
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Edwards KF, Steward GF, Schvarcz CR. Making sense of virus size and the tradeoffs shaping viral fitness. Ecol Lett 2020; 24:363-373. [PMID: 33146939 DOI: 10.1111/ele.13630] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/26/2020] [Accepted: 09/27/2020] [Indexed: 12/18/2022]
Abstract
Viruses span an impressive size range, with genome length varying a thousandfold and virion volume nearly a millionfold. For cellular organisms the scaling of traits with size is a pervasive influence on ecological processes, but whether size plays a central role in viral ecology is unknown. Here, we focus on viruses of aquatic unicellular organisms, which exhibit the greatest known range of virus size. We outline hypotheses within a quantitative framework, and analyse data where available, to consider how size affects the primary components of viral fitness. We argue that larger viruses have fewer offspring per infection and slower contact rates with host cells, but a larger genome tends to increase infection efficiency, broaden host range, and potentially increase attachment success and decrease decay rate. These countervailing selective pressures may explain why a breadth of sizes exist and even coexist when infecting the same host populations. Oligotrophic ecosystems may be enriched in "giant" viruses, because environments with resource-limited phagotrophs at low concentrations may select for broader host range, better control of host metabolism, lower decay rate and a physical size that mimics bacterial prey. Finally, we describe where further research is needed to understand the ecology and evolution of viral size diversity.
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Affiliation(s)
- Kyle F Edwards
- Department of Oceanography, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Grieg F Steward
- Department of Oceanography, University of Hawai'i at Mānoa, Honolulu, HI, USA
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31
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Molina F, Simancas A, Tabla R, Gómez A, Roa I, Rebollo JE. Diversity and Local Coadaptation of Escherichia coli and Coliphages From Small Ruminants. Front Microbiol 2020; 11:564522. [PMID: 33178150 PMCID: PMC7596221 DOI: 10.3389/fmicb.2020.564522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 09/17/2020] [Indexed: 01/21/2023] Open
Abstract
Bacteriophages are highly specific predators that drive bacterial diversity through coevolution while striking tradeoffs among preserving host populations for long-term exploitation and increasing their virulence, structural stability, or host range. Escherichia coli and other coliform bacteria present in the microbiota of milk and during early ripening of raw milk cheeses have been linked to the production of gas, manifested by the appearance of eyes, and the development of off-flavors; thus, they might cause early blowing and cheese spoilage. Here, we report the characterization of coliphages isolated from manure from small ruminant farms and E. coli strains isolated from goat and sheep raw milk cheese. Additionally, the virulence and host range of locally isolated and laboratory collection phages were determined by comparing the susceptibility of E. coli strains from different sources. In agreement with the high genetic diversity found within the species E. coli, clustering analysis of whole-cell protein revealed a total of 13 distinct profiles but none of the raw milk cheese isolates showed inhibition of growth by reference or water-isolated coliphages. Conversely, 10 newly isolated phages had a broad host range (i.e., able to lyse ≥50% of bacterial hosts tested), thus exhibiting utility for biocontrol and only one cheese-isolated E. coli strain was resistant to all the phages. Whereas there was a high positive correlation between bacterial susceptibility range and lysis intensity, the phages virulence decreased as range increased until reaching a plateau. These results suggest local gene-for-gene coevolution between hosts and phages with selective tradeoffs for both resistance and competitive ability of the bacteria and host-range extension and virulence of the phage populations. Hence, different phage cocktail formulations might be required when devising long-term and short-term biocontrol strategies.
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Affiliation(s)
- Felipe Molina
- Department of Biochemistry, Molecular Biology and Genetics, University of Extremadura, Badajoz, Spain
| | - Alfredo Simancas
- Department of Biochemistry, Molecular Biology and Genetics, University of Extremadura, Badajoz, Spain
| | - Rafael Tabla
- Dairy Department, Technological Institute of Food and Agriculture - Scientific and Technological Research Centre of Extremadura, Junta de Extremadura, Badajoz, Spain
| | - Antonia Gómez
- Dairy Department, Technological Institute of Food and Agriculture - Scientific and Technological Research Centre of Extremadura, Junta de Extremadura, Badajoz, Spain
| | - Isidro Roa
- Dairy Department, Technological Institute of Food and Agriculture - Scientific and Technological Research Centre of Extremadura, Junta de Extremadura, Badajoz, Spain
| | - José Emilio Rebollo
- Department of Biochemistry, Molecular Biology and Genetics, University of Extremadura, Badajoz, Spain
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32
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Kim GH, Kim JW, Kim J, Chae JP, Lee JS, Yoon SS. Genetic Analysis and Characterization of a Bacteriophage ØCJ19 Active against Enterotoxigenic Escherichia coli. Food Sci Anim Resour 2020; 40:746-757. [PMID: 32968727 PMCID: PMC7492175 DOI: 10.5851/kosfa.2020.e49] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 06/29/2020] [Accepted: 07/07/2020] [Indexed: 01/21/2023] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is the major pathogenic
E. coli that causes diarrhea and edema in post-weaning
piglets. In this study, we describe the morphology and characteristics of
ØCJ19, a bacteriophage that infects ETEC, and performed genetic analysis.
Phage ØCJ19 belongs to the family Myoviridae. One-step
growth curve showed a latent phase of 5 min and burst size of approximately 20
phage particles/infected cell. Phage infectivity was stable for 2 h between
4°C and 55°C, and the phage was stable between pH 3 and 11.
Genetic analysis revealed that phage ØCJ19 has a total of 49,567 bases
and 79 open reading frames (ORFs). The full genomic sequence of phage
ØCJ19 showed the most similarity to an Escherichia
phage, vB_EcoS_ESCO41. There were no genes encoding lysogeny,
toxins, virulence factors, or antibiotic resistance in this phage, suggesting
that this phage can be used safely as a biological agent to control ETEC.
Comparative genomic analysis in terms of the tail fiber proteins could provide
genetic insight into host recognition and the relationship with other
coliphages. These results showed the possibility to improve food safety by
applying phage ØCJ19 to foods of animal origin contaminated with ETEC and
suggests that it could be the basis for establishing a safety management system
in the animal husbandry.
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Affiliation(s)
- Gyeong-Hwuii Kim
- Department of Biological Science and Technology, Yonsei University, Wonju 26493, Korea
| | - Jae-Won Kim
- Institute of Biotechnology, CJ CheilJedang, Suwon 16495, Korea
| | - Jaegon Kim
- Department of Biological Science and Technology, Yonsei University, Wonju 26493, Korea
| | - Jong Pyo Chae
- Institute of Biotechnology, CJ CheilJedang, Suwon 16495, Korea
| | - Jin-Sun Lee
- Department of Biological Science and Technology, Yonsei University, Wonju 26493, Korea
| | - Sung-Sik Yoon
- Department of Biological Science and Technology, Yonsei University, Wonju 26493, Korea
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33
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Reporter Phage-Based Detection of Bacterial Pathogens: Design Guidelines and Recent Developments. Viruses 2020; 12:v12090944. [PMID: 32858938 PMCID: PMC7552063 DOI: 10.3390/v12090944] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/10/2020] [Accepted: 08/25/2020] [Indexed: 02/06/2023] Open
Abstract
Fast and reliable detection of bacterial pathogens in clinical samples, contaminated food products, and water supplies can drastically improve clinical outcomes and reduce the socio-economic impact of disease. As natural predators of bacteria, bacteriophages (phages) have evolved to bind their hosts with unparalleled specificity and to rapidly deliver and replicate their viral genome. Not surprisingly, phages and phage-encoded proteins have been used to develop a vast repertoire of diagnostic assays, many of which outperform conventional culture-based and molecular detection methods. While intact phages or phage-encoded affinity proteins can be used to capture bacteria, most phage-inspired detection systems harness viral genome delivery and amplification: to this end, suitable phages are genetically reprogrammed to deliver heterologous reporter genes, whose activity is typically detected through enzymatic substrate conversion to indicate the presence of a viable host cell. Infection with such engineered reporter phages typically leads to a rapid burst of reporter protein production that enables highly sensitive detection. In this review, we highlight recent advances in infection-based detection methods, present guidelines for reporter phage construction, outline technical aspects of reporter phage engineering, and discuss some of the advantages and pitfalls of phage-based pathogen detection. Recent improvements in reporter phage construction and engineering further substantiate the potential of these highly evolved nanomachines as rapid and inexpensive detection systems to replace or complement traditional diagnostic approaches.
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34
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Joshi H, Nair G, Gangakhedkar R, Jain V. Understanding the role of the lysozyme-like domain of D29 mycobacteriophage-encoded endolysin in host cell lysis and phage propagation. MICROBIOLOGY-SGM 2020; 165:1013-1023. [PMID: 31264955 DOI: 10.1099/mic.0.000831] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Mycobacteriophages are viruses that infect and kill mycobacteria. The peptidoglycan hydrolase, lysin A (LysA), coded by one of the most potent mycobacteriophages, D29, carries two catalytic domains at its N-terminus and a cell wall-binding domain at its C-terminus. Here, we have explored the importance of the centrally located lysozyme-like catalytic domain (LD) of LysA in phage physiology. We had previously identified an R198A substitution that causes inactivation of the LD when it is present alone on a polypeptide. Here, we show that upon incorporation of the same mutation (i.e. R350A) in full-length LysA, the protein demonstrates substantially reduced activity in vitro, even in the presence of the N-terminal catalytic domain, and has less efficient mycobacterial cell lysis ability when it is expressed in Mycobacterium smegmatis. These data suggest that an active LD is required for the full-length protein to function optimally. Moreover, a mutant D29 phage harbouring this substitution (D29R350A) in its LysA protein shows significantly delayed host M. smegmatis lysis. However, the mutant phage demonstrates an increase in burst size and plaque diameter. Taken together, our data show the importance of an intact LD region in D29 LysA PG hydrolase, and indicate an evolutionary advantage over other phages that lack such a domain in their endolysins.
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Affiliation(s)
- Himanshu Joshi
- Microbiology and Molecular Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal 462066, Madhya Pradesh, India
| | - Gokul Nair
- Microbiology and Molecular Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal 462066, Madhya Pradesh, India
| | - Rutuja Gangakhedkar
- Microbiology and Molecular Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal 462066, Madhya Pradesh, India
| | - Vikas Jain
- Microbiology and Molecular Biology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal 462066, Madhya Pradesh, India
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35
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Abstract
Antiviral drugs have traditionally been developed by directly targeting essential viral components. However, this strategy often fails due to the rapid generation of drug-resistant viruses. Recent genome-wide approaches, such as those employing small interfering RNA (siRNA) or clustered regularly interspaced short palindromic repeats (CRISPR) or those using small molecule chemical inhibitors targeting the cellular "kinome," have been used successfully to identify cellular factors that can support virus replication. Since some of these cellular factors are critical for virus replication, but are dispensable for the host, they can serve as novel targets for antiviral drug development. In addition, potentiation of immune responses, regulation of cytokine storms, and modulation of epigenetic changes upon virus infections are also feasible approaches to control infections. Because it is less likely that viruses will mutate to replace missing cellular functions, the chance of generating drug-resistant mutants with host-targeted inhibitor approaches is minimized. However, drug resistance against some host-directed agents can, in fact, occur under certain circumstances, such as long-term selection pressure of a host-directed antiviral agent that can allow the virus the opportunity to adapt to use an alternate host factor or to alter its affinity toward the target that confers resistance. This review describes novel approaches for antiviral drug development with a focus on host-directed therapies and the potential mechanisms that may account for the acquisition of antiviral drug resistance against host-directed agents.
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36
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The effect of viral plasticity on the persistence of host-virus systems. J Theor Biol 2020; 498:110263. [PMID: 32333976 DOI: 10.1016/j.jtbi.2020.110263] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 02/20/2020] [Accepted: 03/26/2020] [Indexed: 11/21/2022]
Abstract
Phenotypic plasticity plays an important role in the survival of individuals. In microbial host-virus systems, previous studies have shown the stabilizing effect that host plasticity has on the coexistence of the system. By contrast, it remains uncertain how the dependence of the virus on the metabolism of the host (i.e. "viral plasticity") shapes bacteria-phage population dynamics in general, or the stability of the system in particular. Moreover, bacteria-phage models that do not consider viral plasticity are now recognised as overly simplistic. For these reasons, here we focus on the effect of viral plasticity on the stability of the system under different environmental conditions. We compared the predictions from a standard bacteria-phage model, which neglects plasticity, with those of a modification that includes viral plasticity. We investigated under which conditions viral plasticity promotes coexistence, with or without oscillatory dynamics. Our analysis shows that including viral plasticity reveals coexistence in regions of the parameter space where models without plasticity predict a collapse of the system. We also show that viral plasticity tends to reduce population oscillations, although this stabilizing effect is not consistently observed across environmental conditions: plasticity may instead reinforce dynamic feedbacks between the host, the virus, and the environment, which leads to wider oscillations. Our results contribute to a deeper understanding of the dynamic control of bacteriophage on host populations observed in nature.
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37
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Okamoto KW, Amarasekare P, Post DM, Vasseur DA, Turner PE. The interplay between host community structure and pathogen life‐history constraints in driving the evolution of host‐range shifts. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13467] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Kenichi W. Okamoto
- Department of Ecology and Evolutionary Biology Yale University New Haven CT USA
- Department of Biology University of St. Thomas St. Paul MN USA
- Department of Ecology and Evolutionary Biology University of California Los Angeles CA USA
| | - Priyanga Amarasekare
- Department of Ecology and Evolutionary Biology University of California Los Angeles CA USA
| | - David M. Post
- Department of Ecology and Evolutionary Biology Yale University New Haven CT USA
| | - David A. Vasseur
- Department of Ecology and Evolutionary Biology Yale University New Haven CT USA
| | - Paul E. Turner
- Department of Ecology and Evolutionary Biology Yale University New Haven CT USA
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38
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Abedon ST. Look Who's Talking: T-Even Phage Lysis Inhibition, the Granddaddy of Virus-Virus Intercellular Communication Research. Viruses 2019; 11:v11100951. [PMID: 31623057 PMCID: PMC6832632 DOI: 10.3390/v11100951] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/15/2019] [Accepted: 09/30/2019] [Indexed: 12/13/2022] Open
Abstract
That communication can occur between virus-infected cells has been appreciated for nearly as long as has virus molecular biology. The original virus communication process specifically was that seen with T-even bacteriophages-phages T2, T4, and T6-resulting in what was labeled as a lysis inhibition. Another proposed virus communication phenomenon, also seen with T-even phages, can be described as a phage-adsorption-induced synchronized lysis-inhibition collapse. Both are mediated by virions that were released from earlier-lysing, phage-infected bacteria. Each may represent ecological responses, in terms of phage lysis timing, to high local densities of phage-infected bacteria, but for lysis inhibition also to locally reduced densities of phage-uninfected bacteria. With lysis inhibition, the outcome is a temporary avoidance of lysis, i.e., a lysis delay, resulting in increased numbers of virions (greater burst size). Synchronized lysis-inhibition collapse, by contrast, is an accelerated lysis which is imposed upon phage-infected bacteria by virions that have been lytically released from other phage-infected bacteria. Here I consider some history of lysis inhibition, its laboratory manifestation, its molecular basis, how it may benefit expressing phages, and its potential ecological role. I discuss as well other, more recently recognized examples of virus-virus intercellular communication.
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Affiliation(s)
- Stephen T Abedon
- Department of Microbiology, The Ohio State University, Mansfield, OH 44906, USA.
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39
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Thingstad TF, Våge S. Host-virus-predator coexistence in a grey-box model with dynamic optimization of host fitness. ISME JOURNAL 2019; 13:3102-3111. [PMID: 31527663 DOI: 10.1038/s41396-019-0496-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 08/01/2019] [Accepted: 08/15/2019] [Indexed: 11/09/2022]
Abstract
Lytic viruses are believed to affect both flow patterns and host diversity in microbial food webs. Models resolving host and virus communities into subgroups can represent both aspects. However, when flow pattern is the prime interest, such models may seem unnecessary complex. This has led to proposals of black-box models using only total community sizes as state variables. This simplification creates a coexistence problem, however, since predator and virus communities then compete for the same, shared, prey = host community. Mathematically, this problem can be solved by introducing feedbacks allowing community-level properties to adapt. The different mathematical alternatives for such feedback represent different ecological assumptions and thus different hypotheses for how the balance between predators and viruses is controlled in nature. We here explore a model where the feedback works through an increase in host community resistance in response to high virus abundances, thereby reducing virus production. We use a dynamic "strategy" index S to describe the balance between defensive and competitive abilities in the host community, and assume the rate of change in S to be proportional to the local slope of the per capita fitness gradient for the host. We explore how such a "grey-box" model can allow stable coexistence of viruses and predators, and how equilibrium food web structure, virus-to-host ratio, and partitioning of host production varies; both as functions of host community traits, and as functions of external bottom-up and top-down drivers.
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Affiliation(s)
| | - Selina Våge
- Department of Biological Sciences, University of Bergen, 5020, Bergen, Norway
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40
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Genome Analysis of Two Novel Lytic Vibrio maritimus Phages Isolated from the Coastal Surface Seawater of Qingdao, China. Curr Microbiol 2019; 76:1225-1233. [DOI: 10.1007/s00284-019-01736-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 07/03/2019] [Indexed: 12/13/2022]
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Igler C, Abedon ST. Commentary: A Host-Produced Quorum-Sensing Autoinducer Controls a Phage Lysis-Lysogeny Decision. Front Microbiol 2019; 10:1171. [PMID: 31214137 PMCID: PMC6557168 DOI: 10.3389/fmicb.2019.01171] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 05/07/2019] [Indexed: 01/21/2023] Open
Affiliation(s)
- Claudia Igler
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Stephen T. Abedon
- Department of Microbiology, The Ohio State University, Mansfield, OH, United States
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42
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Lysis Profiles of Salmonella Phages on Salmonella Isolates from Various Sources and Efficiency of a Phage Cocktail against S. Enteritidis and S. Typhimurium. Microorganisms 2019; 7:microorganisms7040100. [PMID: 30959743 PMCID: PMC6518243 DOI: 10.3390/microorganisms7040100] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/01/2019] [Accepted: 04/01/2019] [Indexed: 01/01/2023] Open
Abstract
Salmonella enterica serovar Enteritidis and Salmonella enterica serovar Typhimurium are major foodborne pathogens of concern worldwide. Bacteriophage applications have gained more interest for biocontrol in foods. This study isolated 36 Salmonella phages from several animal farms in Thailand and tested them on 47 Salmonella strains from several sources, including farms, seafood processing plant and humans in Thailand and USA. Phages were classified into three major groups. The estimated phage genome size showed the range from 50 ± 2 to 200 ± 2 kb. An effective phage cocktail consisting of three phages was developed. Approximately 4 log CFU/mL of S. Enteritidis and S. Typhimurium could be reduced. These phages revealed a burst size of up to 97.7 on S. Enteritidis and 173.7 PFU/cell on S. Typhimurium. Our phage cocktail could decrease S. Enteritidis on chicken meat and sunflower sprouts by 0.66 log CFU/cm2 and 1.27 log CFU/g, respectively. S. Typhimurium on chicken meat and sunflower sprouts were decreased by 1.73 log CFU/cm2 and 1.17 log CFU/g, respectively. Overall, animal farms in Thailand provided high abundance and diversity of Salmonella phages with the lysis ability on Salmonella hosts from various environments and continents. A developed phage cocktail suggests a potential biocontrol against Salmonella in fresh foods.
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43
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Abstract
Viruses use the host machinery to replicate, and their performance thus depends on the host's physiological state. For bacteriophages, this link between host and viral performance has been characterized empirically and with intracellular theories. Such theories are too detailed to be included in models that study host-phage interactions in the long term, which hinders our understanding of systems that range from pathogens infecting gut bacteria to marine phage shaping the oceans. Here, we combined data and models to study the short- and long-term consequences that host physiology has on bacteriophage performance. We compiled data showing the dependence of lytic-phage traits on host growth rate (referred to as viral phenotypic plasticity) to deduce simple expressions that represent such plasticity. Including these expressions in a standard host-phage model allowed us to understand mechanistically how viral plasticity affects emergent evolutionary strategies and the population dynamics associated with different environmental scenarios including, for example, nutrient pulses or host starvation. Moreover, we show that plasticity on the offspring number drives the phage ecological and evolutionary dynamics by reinforcing feedbacks between host, virus, and environment. Standard models neglect viral plasticity, which therefore handicaps their predictive ability in realistic scenarios. Our results highlight the importance of viral plasticity to unravel host-phage interactions and the need of laboratory and field experiments to characterize viral plastic responses across systems.
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44
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Sharaf A, Oborník M, Hammad A, El-Afifi S, Marei E. Characterization and comparative genomic analysis of virulent and temperate Bacillus megaterium bacteriophages. PeerJ 2018; 6:e5687. [PMID: 30581654 PMCID: PMC6292376 DOI: 10.7717/peerj.5687] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 09/03/2018] [Indexed: 11/20/2022] Open
Abstract
Next-Generation Sequencing (NGS) technologies provide unique possibilities for the comprehensive assessment of the environmental diversity of bacteriophages. Several Bacillus bacteriophages have been isolated, but very few Bacillus megaterium bacteriophages have been characterized. In this study, we describe the biological characteristics, whole genome sequences, and annotations for two new isolates of the B. megaterium bacteriophages (BM5 and BM10), which were isolated from Egyptian soil samples. Growth analyses indicated that the phages BM5 and BM10 have a shorter latent period (25 and 30 min, respectively) and a smaller burst size (103 and 117 PFU, respectively), in comparison to what is typical for Bacillus phages. The genome sizes of the phages BM5 and BM10 were 165,031 bp and 165,213 bp, respectively, with modular organization. Bioinformatic analyses of these genomes enabled the assignment of putative functions to 97 and 65 putative ORFs, respectively. Comparative analysis of the BM5 and BM10 genome structures, in conjunction with other B. megaterium bacteriophages, revealed relatively high levels of sequence and organizational identity. Both genomic comparisons and phylogenetic analyses support the conclusion that the sequenced phages (BM5 and BM10) belong to different sub-clusters (L5 and L7, respectively), within the L-cluster, and display different lifestyles (lysogenic and lytic, respectively). Moreover, sequenced phages encode proteins associated with Bacillus pathogenesis. In addition, BM5 does not contain any tRNA sequences, whereas BM10 genome codes for 17 tRNAs.
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Affiliation(s)
- Abdoallah Sharaf
- Genetic Department, Faculty of Agriculture, Ain Shams University, Cairo, Egypt.,Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Miroslav Oborník
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Adel Hammad
- Department of Microbiology, Faculty of Agriculture, Minia University, Minia, Egypt
| | - Sohair El-Afifi
- Department of Agricultural Microbiology, Virology Laboratory, Ain Shams University, Cairo, Egypt
| | - Eman Marei
- Department of Agricultural Microbiology, Virology Laboratory, Ain Shams University, Cairo, Egypt
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45
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Influence of adaptive mutations, from thermal adaptation experiments, on the infection cycle of RNA bacteriophage Qβ. Arch Virol 2018; 163:2655-2662. [PMID: 29869034 DOI: 10.1007/s00705-018-3895-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 04/05/2018] [Indexed: 10/14/2022]
Abstract
A population's growth rate is determined by multiple 'life history traits'. To quantitatively determine which life history traits should be improved to allow a living organism to adapt to an inhibitory environment is an important issue. Previously, we conducted thermal adaptation experiments on the RNA bacteriophage Qβ using three independent replicates and reported that all three end-point populations could grow at a temperature (43.6°C) that inhibited the growth of the ancestral strain. Even though the fitness values of the endpoint populations were almost the same, their genome sequence was not, indicating that the three thermally adapted populations may have different life history traits. In this study, we introduced each mutation observed in these three end-point populations into the cDNA of the Qβ genome and prepared three different mutants. Quantitative analysis showed that they tended to increase their fitness by increasing the adsorption rate to their host, shortening their latent period (i.e., the duration between phage infection and progeny release), and increasing the burst size (i.e., the number of progeny phages per infected cell), but all three mutants decreased their thermal stability. However, the degree to which these traits changed differed. The mutant with the least mutations showed a smaller decrease in thermal stability, the largest adsorption rate to the host, and the shortest latent period. These results indicated that several different adaptive routes exist by which Qβ can adapt to higher temperatures, even though Qβ is a simple RNA bacteriophage with a small genome size, encoding only four genes.
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46
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ElNaker NA, Elektorowicz M, Naddeo V, Hasan SW, Yousef AF. Assessment of Microbial Community Structure and Function in Serially Passaged Wastewater Electro-Bioreactor Sludge: An Approach to Enhance Sludge Settleability. Sci Rep 2018; 8:7013. [PMID: 29725134 PMCID: PMC5934391 DOI: 10.1038/s41598-018-25509-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/17/2018] [Indexed: 11/23/2022] Open
Abstract
Several studies have been carried out to understand bulking phenomena and the importance of environmental factors on sludge settling characteristics. The main objective of this study was to carry out functional characterization of microbial community structure of wastewater electro-bioreactor sludge as it undergoes serial passaging in the presence or absence of a current density over 15 days. Illumina MiSeq sequencing and QIIME were used to assess sludge microbial community shifts over time. (α) and (β) diversity analysis were conducted to assess the microbial diversity in electro-bioreactors. A phylogeny-based weighted UniFrac distance analysis was used to compare between bacterial communities while BIO-ENV trend and Spearman’s rank correlation analysis were performed to investigate how reactor operational parameters correlated with bacterial community diversity. Results showed that the removal efficiency of soluble chemical oxygen demand (sCOD) ranged from 91–97%, while phosphorous (PO43−-P) removal was approximately 99%. Phylogenetic analysis revealed stark differences in the development of sludge microbial communities in the control and treatment reactor. There was no mention of any studies aimed at characterizing functional microbial communities under electric field and the results communicated here are the first, to our knowledge, that address this gap in the literature.
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Affiliation(s)
- Nancy A ElNaker
- Department of Chemistry, Khalifa University of Science and Technology, Masdar City Campus, PO Box, 54224, Abu Dhabi, United Arab Emirates.,Department of Chemical Engineering, Khalifa University of Science and Technology, Masdar City Campus, PO Box, 54224, Abu Dhabi, United Arab Emirates
| | - Maria Elektorowicz
- Department of Building, Civil and Environmental Engineering, Concordia University, 1455 Blvd de Maisonneuve W., Montreal, Quebec, H3G 1M8, Canada
| | - Vincenzo Naddeo
- Department of Civil Engineering, University of Salerno - Via Giovanni Paolo II #132, 84084, Fisciano (SA), Italy
| | - Shadi W Hasan
- Department of Chemical Engineering, Khalifa University of Science and Technology, Masdar City Campus, PO Box, 54224, Abu Dhabi, United Arab Emirates.
| | - Ahmed F Yousef
- Department of Chemistry, Khalifa University of Science and Technology, Masdar City Campus, PO Box, 54224, Abu Dhabi, United Arab Emirates.
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47
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Abstract
Viruses are integral to ecological and evolutionary processes, but we have a poor understanding of what drives variation in key traits across diverse viruses. For lytic viruses, burst size, latent period, and genome size are primary characteristics controlling host-virus dynamics. Here we synthesize data on these traits for 75 strains of phytoplankton viruses, which play an important role in global biogeochemistry. We find that primary traits of the host (genome size, growth rate) explain 40%-50% of variation in burst size and latent period. Specifically, burst size and latent period both exhibit saturating relationships versus the host∶virus genome size ratio, with both traits increasing at low genome size ratios while showing no relationship at high size ratios. In addition, latent period declines as host growth rate increases. We analyze a model of latent period evolution to explore mechanisms that could cause these patterns. The model predicts that burst size may often be set by the host genomic resources available for viral construction, while latent period evolves to permit this maximal burst size, modulated by host metabolic rate. These results suggest that general mechanisms may underlie the evolution of diverse viruses. Future extensions of this work could help explain viral regulation of host populations, viral influence on community structure and diversity, and viral roles in biogeochemical cycles.
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48
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Neagu IA, Olejarz J, Freeman M, Rosenbloom DI, Nowak MA, Hill AL. Life cycle synchronization is a viral drug resistance mechanism. PLoS Comput Biol 2018; 14:e1005947. [PMID: 29447150 PMCID: PMC5813899 DOI: 10.1371/journal.pcbi.1005947] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 12/14/2017] [Indexed: 11/19/2022] Open
Abstract
Viral infections are one of the major causes of death worldwide, with HIV infection alone resulting in over 1.2 million casualties per year. Antiviral drugs are now being administered for a variety of viral infections, including HIV, hepatitis B and C, and influenza. These therapies target a specific phase of the virus's life cycle, yet their ultimate success depends on a variety of factors, such as adherence to a prescribed regimen and the emergence of viral drug resistance. The epidemiology and evolution of drug resistance have been extensively characterized, and it is generally assumed that drug resistance arises from mutations that alter the virus's susceptibility to the direct action of the drug. In this paper, we consider the possibility that a virus population can evolve towards synchronizing its life cycle with the pattern of drug therapy. The periodicity of the drug treatment could then allow for a virus strain whose life cycle length is a multiple of the dosing interval to replicate only when the concentration of the drug is lowest. This process, referred to as "drug tolerance by synchronization", could allow the virus population to maximize its overall fitness without having to alter drug binding or complete its life cycle in the drug's presence. We use mathematical models and stochastic simulations to show that life cycle synchronization can indeed be a mechanism of viral drug tolerance. We show that this effect is more likely to occur when the variability in both viral life cycle and drug dose timing are low. More generally, we find that in the presence of periodic drug levels, time-averaged calculations of viral fitness do not accurately predict drug levels needed to eradicate infection, even if there is no synchronization. We derive an analytical expression for viral fitness that is sufficient to explain the drug-pattern-dependent survival of strains with any life cycle length. We discuss the implications of these findings for clinically relevant antiviral strategies.
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Affiliation(s)
- Iulia A. Neagu
- Program for Evolutionary Dynamics, Department of Mathematics and Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America
- Department of Physics, Harvard University, Cambridge, Massachusetts, United States of America
| | - Jason Olejarz
- Program for Evolutionary Dynamics, Department of Mathematics and Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Mark Freeman
- Program for Evolutionary Dynamics, Department of Mathematics and Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Daniel I.S. Rosenbloom
- Department of Biomedical Informatics, Columbia University Medical Center, New York, New York, United States of America
| | - Martin A. Nowak
- Program for Evolutionary Dynamics, Department of Mathematics and Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Alison L. Hill
- Program for Evolutionary Dynamics, Department of Mathematics and Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America
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49
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Abedon ST, LeJeune JT. Why Bacteriophage Encode Exotoxins and other Virulence Factors. Evol Bioinform Online 2017. [DOI: 10.1177/117693430500100001] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This study considers gene location within bacteria as a function of genetic element mobility. Our emphasis is on prophage encoding of bacterial virulence factors (VFs). At least four mechanisms potentially contribute to phage encoding of bacterial VFs: (i) Enhanced gene mobility could result in greater VF gene representation within bacterial populations. We question, though, why certain genes but not others might benefit from this mobility. (ii) Epistatic interactions—between VF genes and phage genes that enhance VF utility to bacteria—could maintain phage genes via selection acting on individual, VF-expressing bacteria. However, is this mechanism sufficient to maintain the rest of phage genomes or, without gene co-regulation, even genetic linkage between phage and VF genes? (iii) Phage could amplify VFs during disease progression by carrying them to otherwise commensal bacteria colocated within the same environment. However, lytic phage kill bacteria, thus requiring assumptions of inclusive fitness within bacterial populations to explain retention of phage-mediated VF amplification for the sake of bacterial utility. Finally, (iv) phage-encoded VFs could enhance phage Darwinian fitness, particularly by acting as ecosystem-modifying agents. That is, VF-supplied nutrients could enhance phage growth by increasing the density or by improving the physiology of phage-susceptible bacteria. Alternatively, VF-mediated break down of diffusion-inhibiting spatial structure found within the multicellular bodies of host organisms could augment phage dissemination to new bacteria or to environments. Such phage-fitness enhancing mechanisms could apply particularly given VF expression within microbiologically heterogeneous environments, ie, ones where phage have some reasonable potential to acquire phage-susceptible bacteria.
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Affiliation(s)
| | - Jeffrey T. LeJeune
- Food Animal Health Research Program, Ohio State University, Wooster, Ohio
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50
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Howard-Varona C, Roux S, Dore H, Solonenko NE, Holmfeldt K, Markillie LM, Orr G, Sullivan MB. Regulation of infection efficiency in a globally abundant marine Bacteriodetes virus. THE ISME JOURNAL 2017; 11:284-295. [PMID: 27187794 PMCID: PMC5335546 DOI: 10.1038/ismej.2016.81] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 03/29/2016] [Accepted: 04/03/2016] [Indexed: 12/19/2022]
Abstract
Bacteria impact humans, industry and nature, but do so under viral constraints. Problematically, knowledge of viral infection efficiencies and outcomes derives from few model systems that over-represent efficient lytic infections and under-represent virus-host natural diversity. Here we sought to understand infection efficiency regulation in an emerging environmental Bacteroidetes-virus model system with markedly different outcomes on two genetically and physiologically nearly identical host strains. For this, we quantified bacterial virus (phage) and host DNA, transcripts and phage particles throughout both infections. While phage transcriptomes were similar, transcriptional differences between hosts suggested host-derived regulation of infection efficiency. Specifically, the alternative host overexpressed DNA degradation genes and underexpressed translation genes, which seemingly targeted phage DNA particle production, as experiments revealed they were both significantly delayed (by >30 min) and reduced (by >50%) in the inefficient infection. This suggests phage failure to repress early alternative host expression and stress response allowed the host to respond against infection by delaying phage DNA replication and protein translation. Given that this phage type is ubiquitous and abundant in the global oceans and that variable viral infection efficiencies are central to dynamic ecosystems, these data provide a critically needed foundation for understanding and modeling viral infections in nature.
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Affiliation(s)
| | - Simon Roux
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
| | - Hugo Dore
- Département de biologie, ENS Lyon, Lyon, France
| | - Natalie E Solonenko
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
| | - Karin Holmfeldt
- School of Natural Sciences, Linnaeus University, Kalmar, Sweden
| | - Lye M Markillie
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory (PNNL), Richland, WA, USA
| | - Galya Orr
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory (PNNL), Richland, WA, USA
| | - Matthew B Sullivan
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
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