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Wagemans J, Tsonos J, Holtappels D, Fortuna K, Hernalsteens JP, De Greve H, Estrozi LF, Bacia-Verloop M, Moriscot C, Noben JP, Schoehn G, Lavigne R. Structural Analysis of Jumbo Coliphage phAPEC6. Int J Mol Sci 2020; 21:ijms21093119. [PMID: 32354127 PMCID: PMC7247149 DOI: 10.3390/ijms21093119] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 04/27/2020] [Accepted: 04/27/2020] [Indexed: 01/24/2023] Open
Abstract
The phAPEC6 genome encodes 551 predicted gene products, with the vast majority (83%) of unknown function. Of these, 62 have been identified as virion-associated proteins by mass spectrometry (ESI-MS/MS), including the major capsid protein (Gp225; present in 1620 copies), which shows a HK97 capsid protein-based fold. Cryo-electron microscopy experiments showed that the 350-kbp DNA molecule of Escherichia coli virus phAPEC6 is packaged in at least 15 concentric layers in the phage capsid. A capsid inner body rod is also present, measuring about 91 nm by 18 nm and oriented along the portal axis. In the phAPEC6 contractile tail, 25 hexameric stacked rings can be distinguished, built of the identified tail sheath protein (Gp277). Cryo-EM reconstruction reveals the base of the unique hairy fibers observed during an initial transmission electron microscopy (TEM) analysis. These very unusual filaments are ordered at three annular positions along the contractile sheath, as well as around the capsid, and may be involved in host interaction.
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Affiliation(s)
- Jeroen Wagemans
- Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21—box 2462, 3001 Leuven, Belgium; (J.W.); (J.T.); (D.H.); (K.F.)
| | - Jessica Tsonos
- Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21—box 2462, 3001 Leuven, Belgium; (J.W.); (J.T.); (D.H.); (K.F.)
- Department of Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel, Belgium;
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium;
| | - Dominique Holtappels
- Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21—box 2462, 3001 Leuven, Belgium; (J.W.); (J.T.); (D.H.); (K.F.)
| | - Kiandro Fortuna
- Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21—box 2462, 3001 Leuven, Belgium; (J.W.); (J.T.); (D.H.); (K.F.)
| | | | - Henri De Greve
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium;
- VIB Center for Structural Biology, Pleinlaan 2, 1050 Brussels, Belgium
| | - Leandro F. Estrozi
- Univ. Grenoble Alpes, CEA, CNRS, IBS, F-38000 Grenoble, France; (L.F.E.); (M.B.-V.)
| | - Maria Bacia-Verloop
- Univ. Grenoble Alpes, CEA, CNRS, IBS, F-38000 Grenoble, France; (L.F.E.); (M.B.-V.)
| | - Christine Moriscot
- Univ. Grenoble Alpes, CNRS, CEA, EMBL, Integrated Structural Biology Grenoble (ISBG), F-38042 Grenoble, France;
| | - Jean-Paul Noben
- Biomedical Research Institute and Transnational University Limburg, Hasselt University, Agoralaan D, 3590 Hasselt, Belgium;
| | - Guy Schoehn
- Univ. Grenoble Alpes, CEA, CNRS, IBS, F-38000 Grenoble, France; (L.F.E.); (M.B.-V.)
- Correspondence: (G.S.); (R.L.); Tel.: +33-4-5742-8568 (G.S.); +32-16-3795-24 (R.L.)
| | - Rob Lavigne
- Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21—box 2462, 3001 Leuven, Belgium; (J.W.); (J.T.); (D.H.); (K.F.)
- Correspondence: (G.S.); (R.L.); Tel.: +33-4-5742-8568 (G.S.); +32-16-3795-24 (R.L.)
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Kaczorowska J, Casey E, Neve H, Franz CM, Noben JP, Lugli GA, Ventura M, van Sinderen D, Mahony J. A Quest of Great Importance-Developing a Broad Spectrum Escherichia coli Phage Collection. Viruses 2019; 11:v11100899. [PMID: 31561510 PMCID: PMC6832132 DOI: 10.3390/v11100899] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 09/14/2019] [Accepted: 09/24/2019] [Indexed: 12/15/2022] Open
Abstract
Shigella ssp. and enterotoxigenic Escherichiacoli are the most common etiological agents of diarrheal diseases in malnourished children under five years of age in developing countries. The ever-growing issue of antibiotic resistance and the potential negative impact of antibiotic use on infant commensal microbiota are significant challenges to current therapeutic approaches. Bacteriophages (or phages) represent an alternative treatment that can be used to treat specific bacterial infections. In the present study, we screened water samples from both environmental and industrial sources for phages capable of infecting E. coli laboratory strains within our collection. Nineteen phages were isolatedand tested for their ability to infect strains within the ECOR collection and E. coli O157:H7 Δstx. Furthermore, since coliphages have been reported to cross-infect certain Shigella spp., we also evaluated the ability of the nineteen phages to infect a representative Shigella sonnei strain from our collection. Based on having distinct (although overlapping in some cases) host ranges, ten phage isolates were selected for genome sequence and morphological characterization. Together, these ten selected phages were shown to infect most of the ECOR library, with 61 of the 72 strains infected by at least one phage from our collection. Genome analysis of the ten phages allowed classification into five previously described genetic subgroups plus one previously underrepresented subgroup.
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Affiliation(s)
- Joanna Kaczorowska
- School of Microbiology and APC Microbiome Ireland, University College Cork, Western Road, T12 YT20 Cork, Ireland; (J.K.); (E.C.)
| | - Eoghan Casey
- School of Microbiology and APC Microbiome Ireland, University College Cork, Western Road, T12 YT20 Cork, Ireland; (J.K.); (E.C.)
| | - Horst Neve
- Department of Microbiology and Biotechnology, Max Rubner-Institut, 24103 Kiel, Germany; (H.N.)
| | - Charles M.A.P. Franz
- Department of Microbiology and Biotechnology, Max Rubner-Institut, 24103 Kiel, Germany; (H.N.)
| | - Jean-Paul Noben
- Biomedical Research Institute, Hasselt University, B-3590 Diepenbeek, Belgium;
| | - Gabriele A. Lugli
- Laboratory of Probiogenomics, Dept. Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (G.A.L.); (M.V.)
| | - Marco Ventura
- Laboratory of Probiogenomics, Dept. Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (G.A.L.); (M.V.)
| | - Douwe van Sinderen
- School of Microbiology and APC Microbiome Ireland, University College Cork, Western Road, T12 YT20 Cork, Ireland; (J.K.); (E.C.)
- Correspondence: (D.v.S.); (J.M.)
| | - Jennifer Mahony
- School of Microbiology and APC Microbiome Ireland, University College Cork, Western Road, T12 YT20 Cork, Ireland; (J.K.); (E.C.)
- Correspondence: (D.v.S.); (J.M.)
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Korf IHE, Meier-Kolthoff JP, Adriaenssens EM, Kropinski AM, Nimtz M, Rohde M, van Raaij MJ, Wittmann J. Still Something to Discover: Novel Insights into Escherichia coli Phage Diversity and Taxonomy. Viruses 2019; 11:E454. [PMID: 31109012 PMCID: PMC6563267 DOI: 10.3390/v11050454] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 04/29/2019] [Accepted: 05/15/2019] [Indexed: 12/18/2022] Open
Abstract
The aim of this study was to gain further insight into the diversity of Escherichia coli phagesfollowed by enhanced work on taxonomic issues in that field. Therefore, we present the genomiccharacterization and taxonomic classification of 50 bacteriophages against E. coli isolated fromvarious sources, such as manure or sewage. All phages were examined for their host range on a setof different E. coli strains, originating, e.g., from human diagnostic laboratories or poultry farms.Transmission electron microscopy revealed a diversity of morphotypes (70% Myo-, 22% Sipho-, and8% Podoviruses), and genome sequencing resulted in genomes sizes from ~44 to ~370 kb.Annotation and comparison with databases showed similarities in particular to T4- and T5-likephages, but also to less-known groups. Though various phages against E. coli are already describedin literature and databases, we still isolated phages that showed no or only few similarities to otherphages, namely phages Goslar, PTXU04, and KWBSE43-6. Genome-based phylogeny andclassification of the newly isolated phages using VICTOR resulted in the proposal of new generaand led to an enhanced taxonomic classification of E. coli phages.
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Affiliation(s)
- Imke H E Korf
- Leibniz Institute DSMZ⁻German Collection of Microorganisms and Cell Cultures, 38124 Braunschweig,Germany.
| | - Jan P Meier-Kolthoff
- Leibniz Institute DSMZ⁻German Collection of Microorganisms and Cell Cultures, 38124 Braunschweig,Germany.
| | | | - Andrew M Kropinski
- Departments of Food Science and Pathobiology, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - Manfred Nimtz
- Protein Analytics Platform, Helmholtz-Centre for Infection Research (HZI), 38124 Braunschweig,Germany.
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz-Centre for Infection Research (HZI), 38124 Braunschweig,Germany.
| | - Mark J van Raaij
- Department of Macromolecular Structure, Centro Nacional de Biotecnologia CNB-CSIC, 28049 Madrid,Spain.
| | - Johannes Wittmann
- Leibniz Institute DSMZ⁻German Collection of Microorganisms and Cell Cultures, 38124 Braunschweig,Germany.
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Sváb D, Falgenhauer L, Rohde M, Chakraborty T, Tóth I. Identification and characterization of new broad host-range rV5-like coliphages C203 and P206 directed against enterobacteria. Infect Genet Evol 2018; 64:254-261. [PMID: 30033383 DOI: 10.1016/j.meegid.2018.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/08/2018] [Accepted: 07/03/2018] [Indexed: 11/18/2022]
Abstract
We isolated and characterized two novel rV5-like lytic bacteriophages from independently collected food samples. Nucleotide sequence analysis revealed that these phages have linear double-stranded DNA genomes comprising 138,073 bp with 213 CDS and 5 tRNA genes. The two genomes contain completely identical nucleotide sequence, albeit there is a 10,718 bp-long shift in the sequence. The GC content of the phage genomes was 43.7% and they showed high general homology to rV5-like phages. The new phages were termed C203 and P206. The genome of both phages contains a unique ORF that encodes for a putative phage homing endonuclease. The phage produced clear plaques with a burst size of approx. 1000 viral particles and a latent period of 60 min. Morphological investigation indicated that the new phages are members of the family Myoviridae with an approximate head length of 85 nm, tail length of 75 nm, and a head width of 96 nm. C203 and P206 exhibit a broad and uniform host range, which included enterohemorrhagic Escherichia coli strains of serogroup O157, multi drug resistant (MDR) E. coli strains of various sero- and pathotypes, and both Shigella sonnei and S. dysenteriae strains. C203 and P206 both effectively reduced the number of living EHEC O157:H7 Sakai in experimentally inoculated minced meat. The same broad host range, the lack of any virulence related genes, the stability and its short latent period suggest that these newly found phages could be suitable candidates as a bio-control agents against food-borne pathogenic Enterobacteria.
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Affiliation(s)
- Domonkos Sváb
- Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary.
| | - Linda Falgenhauer
- Institute of Medical Microbiology, Justus Liebig University Giessen, German Center for Infection Research (DZIF), Partner site Giessen-Marburg-Langen, Giessen, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, HZI, Braunschweig, Germany
| | - Trinad Chakraborty
- Institute of Medical Microbiology, Justus Liebig University Giessen, German Center for Infection Research (DZIF), Partner site Giessen-Marburg-Langen, Giessen, Germany
| | - István Tóth
- Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary.
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Jebri S, Hmaied F, Yahya M, Ben Ammar A, Hamdi M. Total coliphages removal by activated sludge process and their morphological diversity by transmission electron microscopy. Water Sci Technol 2016; 74:318-23. [PMID: 27438235 DOI: 10.2166/wst.2016.178] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
This study was conducted to isolate phages in treated sewage collected from wastewater treatment plant, and explore their morphological diversity by transmission electron microscopy (TEM). Fates of total bacteriophages and their reduction by biological treatment were also assayed. Phages were isolated using the plaque assay then negatively stained and observed by electron microscope. Electron micrographs showed different types of phages with different shapes and sizes. The majority of viruses found in treated sewage ranged from 30 to 100 nm in capsid diameter. Many of them were tailed, belonging to Siphoviridae, Myoviridae and Podoviridae families. Non-tailed phage particles were also found at a low rate, presumably belonging to Leviviridae or Microviridae families. This study shows the diversity and the abundance of bacteriophages in wastewater after biological treatment. Their persistence in wastewater reused in agriculture should raise concerns about their potential role in controlling bacterial populations in the environment. They should be also included in water treatment quality controlling guidelines as fecal and viral indicators.
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Affiliation(s)
- Sihem Jebri
- Unité de Microbiologie et de Biologie Moléculaire, CNSTN, Technopôle de Sidi Thabet, 2020 Sidi Thabet, Tunisia E-mail:
| | - Fatma Hmaied
- Unité de Microbiologie et de Biologie Moléculaire, CNSTN, Technopôle de Sidi Thabet, 2020 Sidi Thabet, Tunisia E-mail:
| | - Mariem Yahya
- Unité de Microbiologie et de Biologie Moléculaire, CNSTN, Technopôle de Sidi Thabet, 2020 Sidi Thabet, Tunisia E-mail:
| | - Aouatef Ben Ammar
- Faculté de médecine de Tunis, Unité de Microscopie électronique, Bab Saâdoun, 1007 Tunis, Tunisia
| | - Moktar Hamdi
- Tunis Carthage University, Institut National Sciences Appliquées de Tunis, Laboratoire Ecologie Technologie Microbienne, BP 676, 1080 Tunis, Tunisia
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Shahrbabak SS, Khodabandehlou Z, Shahverdi AR, Skurnik M, Ackermann HW, Varjosalo M, Yazdi MT, Sepehrizadeh Z. Isolation, characterization and complete genome sequence of PhaxI: a phage of Escherichia coli O157 : H7. Microbiology (Reading) 2013; 159:1629-1638. [PMID: 23676434 DOI: 10.1099/mic.0.063776-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bacteriophages are considered as promising biological agents for the control of infectious diseases. Sequencing of their genomes can ascertain the absence of antibiotic resistance, toxin or virulence genes. The anti-O157 : H7 coliphage, PhaxI, was isolated from a sewage sample in Iran. Morphological studies by transmission electron microscopy showed that it has an icosahedral capsid of 85-86 nm and a contractile tail of 115×15 nm. PhaxI contains dsDNA composed of 156 628 nt with a G+C content of 44.5 mol% that encodes 209 putative proteins. In MS analysis of phage particles, 92 structural proteins were identified. PhaxI lyses Escherichia coli O157 : H7 in Luria-Bertani medium and milk, has an eclipse period of 20 min and a latent period of 40 min, and has a burst size of about 420 particles per cell. PhaxI is a member of the genus 'Viunalikevirus' of the family Myoviridae and is specific for E. coli O157 : H7.
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Affiliation(s)
- Salehe Sabouri Shahrbabak
- Pharmaceutics Research Center, Kerman University of Medical Sciences, PO Box 76175-493, Kerman, Iran
- Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, PO Box 14155-6451, Tehran, Iran
| | - Zahra Khodabandehlou
- Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, PO Box 14155-6451, Tehran, Iran
| | - Ahmad Reza Shahverdi
- Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, PO Box 14155-6451, Tehran, Iran
| | - Mikael Skurnik
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki and Helsinki University Central Hospital Laboratory, Helsinki, Finland
| | - Hans-Wolfgang Ackermann
- Department of Microbiology, Immunology, and Infectiology, Faculty of Medicine, Laval University, Quebec, QC; G1X 4C6, Canada
| | - Markku Varjosalo
- Institute of Biotechnology, PO Box 65, University of Helsinki, Helsinki, Finland
| | - Mojtaba Tabatabaei Yazdi
- Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, PO Box 14155-6451, Tehran, Iran
| | - Zargham Sepehrizadeh
- Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, PO Box 14155-6451, Tehran, Iran
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Kropinski AM, Lingohr EJ, Moyles DM, Ojha S, Mazzocco A, She YM, Bach SJ, Rozema EA, Stanford K, McAllister TA, Johnson RP. Endemic bacteriophages: a cautionary tale for evaluation of bacteriophage therapy and other interventions for infection control in animals. Virol J 2012; 9:207. [PMID: 22985539 PMCID: PMC3496638 DOI: 10.1186/1743-422x-9-207] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 08/31/2012] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND One of the most effective targets for control of zoonotic foodborne pathogens in the farm to fork continuum is their elimination in food animals destined for market. Phage therapy for Escherichia coli O157:H7 in ruminants, the main animal reservoir of this pathogen, is a popular research topic. Since phages active against this pathogen may be endemic in host animals and their environment, they may emerge during trials of phage therapy or other interventions, rendering interpretation of trials problematic. METHODS During separate phage therapy trials, sheep and cattle inoculated with 109 to 1010 CFU of E. coli O157:H7 soon began shedding phages dissimilar in plaque morphology to the administered therapeutic phages. None of the former was previously identified in the animals or in their environment. The dissimilar "rogue" phage was isolated and characterized by host range, ultrastructure, and genomic and proteomic analyses. RESULTS The "rogue" phage (Phage vB_EcoS_Rogue1) is distinctly different from the administered therapeutic Myoviridae phages, being a member of the Siphoviridae (head: 53 nm; striated tail: 152x8 nm). It has a 45.8 kb genome which is most closely related to coliphage JK06, a member of the "T1-like viruses" isolated in Israel. Detailed bioinformatic analysis reveals that the tail of these phages is related to the tail genes of coliphage lambda. The presence of "rogue" phages resulting from natural enrichments can pose problems in the interpretation of phage therapeutic studies. Similarly, evaluation of any interventions for foodborne or other bacterial pathogens in animals may be compromised unless tests for such phages are included to identify their presence and potential impact.
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Affiliation(s)
- Andrew M Kropinski
- Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, 110 Stone Road West, Guelph, ON, N1G 3 W4, Canada
- Department of Molecular & Cellular Biology, University of Guelph, Guelph, ON, N1G 2 W1, Canada
| | - Erika J Lingohr
- Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, 110 Stone Road West, Guelph, ON, N1G 3 W4, Canada
| | - Dianne M Moyles
- Department of Molecular & Cellular Biology, University of Guelph, Guelph, ON, N1G 2 W1, Canada
| | - Shivani Ojha
- Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, 110 Stone Road West, Guelph, ON, N1G 3 W4, Canada
| | - Amanda Mazzocco
- Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, 110 Stone Road West, Guelph, ON, N1G 3 W4, Canada
| | - Yi-Min She
- Centre for Vaccine Evaluation, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, ON, K1A 0 K9, Canada
| | - Susan J Bach
- Agriculture and Agri-Food Canada, Pacific Agri-Food Research Centre, Summerland, BC, V0H 1Z0, Canada
| | - Erica A Rozema
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada
- Alberta Agriculture and Rural Development, Agriculture Centre, Lethbridge, AB, T1J 4 V6, Canada
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, AB, T1J 4B1, Canada
| | - Kim Stanford
- Alberta Agriculture and Rural Development, Agriculture Centre, Lethbridge, AB, T1J 4 V6, Canada
| | - Tim A McAllister
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, AB, T1J 4B1, Canada
| | - Roger P Johnson
- Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, 110 Stone Road West, Guelph, ON, N1G 3 W4, Canada
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Golomidova A, Kulikov E, Isaeva A, Manykin A, Letarov A. The diversity of coliphages and coliforms in horse feces reveals a complex pattern of ecological interactions. Appl Environ Microbiol 2007; 73:5975-81. [PMID: 17704275 PMCID: PMC2075005 DOI: 10.1128/aem.01145-07] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The diversity of coliphages and indigenous coliform strains (ICSs) simultaneously present in horse feces was investigated by culture-based and molecular methods. The richness of coliforms (as estimated by the Chao1 method) is about 1,000 individual ICSs distinguishable by genomic fingerprinting present in a single sample of feces. This unexpectedly high value indicates that some factor limits the competition of coliform bacteria in the horse gut microbial system. In contrast, the diversity of phages active against any selected ICS is generally limited to one to three viral genotypes present in the sample. The sensitivities of different ICSs to simultaneously present coliphages overlap only slightly; the phages isolated from the same sample on different ICSs are usually unrelated. As a result, the titers of phages in fecal extract as determined for different Escherichia coli strains and ICSs may differ by several orders of magnitude. Summarizing all the data, we propose that coliphage infection may provide a selection pressure that maintains the high level of coliform diversity, restricting the possibility of a few best competitors outgrowing other ICSs. We also observed high-magnitude temporal variations of coliphage titers as determined using an E. coli C600 test culture in the same animal during a 16-day period of monitoring. No correlation with total coliform count was observed. These results are in good agreement with our hypothesis.
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Affiliation(s)
- Alla Golomidova
- S. N. Winogradsky Institute of Microbiology RAS, prospekt 60-letiya Oktyabrya, 7/2, Moscow 117312, Russia
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King MR, Vimr RP, Steenbergen SM, Spanjaard L, Plunkett G, Blattner FR, Vimr ER. Escherichia coli K1-specific bacteriophage CUS-3 distribution and function in phase-variable capsular polysialic acid O acetylation. J Bacteriol 2007; 189:6447-56. [PMID: 17601779 PMCID: PMC1951898 DOI: 10.1128/jb.00657-07] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli K1 is the leading cause of human neonatal sepsis and meningitis and is important in other clinical syndromes of both humans and domestic animals; in this strain the polysialic acid capsule (K1 antigen) functions by inhibiting innate immunity. Recent discovery of the phase-variable capsular O acetylation mechanism indicated that the O-acetyltransferase gene, neuO, is carried on a putative K1-specific prophage designated CUS-3 (E. L. Deszo, S. M. Steenbergen, D. I. Freedberg, and E. R. Vimr, Proc. Natl. Acad. Sci. USA 102:5564-5569, 2005). Here we describe the isolation and characterization of a CUS-3 derivative (CUS-3a), demonstrating its morphology, lysogenization of a sensitive host, and the distribution of CUS-3 among a collection of 111 different K1 strains. The 40,207-bp CUS-3 genome was annotated from the strain RS218 genomic DNA sequence, indicating that most of the 63 phage open reading frames have their closest homologues in one of seven different lambdoid phages. Translational fusion of a reporter lacZ fragment to the hypervariable poly-Psi domain facilitated measurement of phase variation frequencies, indicating no significant differences between switch rates or effects on rates of the methyl-directed mismatch repair system. PCR analysis of poly-Psi domain length indicated preferential loss or gain of single 5'-AAGACTC-3' nucleotide repeats. Analysis of a K1 strain previously reported as "locked on" indicated a poly-Psi region with the least number of heptad repeats compatible with in-frame neuO expression. The combined results establish CUS-3 as an active mobile contingency locus in E. coli K1, indicating its capacity to mediate population-wide capsule variation.
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Affiliation(s)
- Michael R King
- Laboratory of Sialobiology and Comparative Metabolomics, Department of Pathobiology, University of Illinois at Urbana-Champain, Urbana, IL 61802, USA
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Jamalludeen N, Johnson RP, Friendship R, Kropinski AM, Lingohr EJ, Gyles CL. Isolation and characterization of nine bacteriophages that lyse O149 enterotoxigenic Escherichia coli. Vet Microbiol 2007; 124:47-57. [PMID: 17560053 DOI: 10.1016/j.vetmic.2007.03.028] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Revised: 03/09/2007] [Accepted: 03/22/2007] [Indexed: 11/20/2022]
Abstract
The goal of this study was to isolate and characterize phages that might be used in prevention and treatment of porcine post-weaning diarrhea due to O149 enterotoxigenic E. coli (ETEC). Serotype O149:H10:F4 was especially targeted because this is the dominant ETEC serotype. Mixtures of 10 strains of O149:H10:F4 ETEC and of 10 O149:H43:F4 ETEC were used as hosts for isolation of phages in sewage from 38 Ontario pig farms. Six phages (GJ1-GJ6) that lysed O149:H10:F4 ETEC and three (GJ7-GJ9) that lysed O149:H43:F4 ETEC were isolated. All phages produced large, clear plaques. All nine phages had necks and contractile tails and therefore belonged to the Myoviridae. Their estimated genome sizes were 48.3-50.7kb and their restriction enzyme fragments suggested that they were closely related. Phages GJ1-GJ6 lysed 99-100% of 85 O149:H10:F4 ETEC, 0-12% of 42 O149:H43:F4 ETEC, 3-35% of 37 non-O149 porcine ETEC, and 6-68% of the 72 strains of the ECOR collection. Phages GJ7-GJ9 lysed 86-98% of the O149:H43:F4 ETEC, 2-53% of the O149:H10:F4 ETEC, and 24-41% of the non-O149 porcine ETEC. Titres of the nine phages were unaffected by exposure for 16h to pH 5-9. Among phages GJ1-GJ6, resistance of O149:H10:F4 ETEC to one phage was generally not accompanied by resistance to other phages. It is concluded that the nine phages are suitable candidates for prophylaxis and therapy of porcine post-weaning diarrhea due to O149 ETEC.
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Affiliation(s)
- Nidham Jamalludeen
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
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12
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Stummeyer K, Schwarzer D, Claus H, Vogel U, Gerardy-Schahn R, Mühlenhoff M. Evolution of bacteriophages infecting encapsulated bacteria: lessons from Escherichia coli K1-specific phages. Mol Microbiol 2007; 60:1123-35. [PMID: 16689790 DOI: 10.1111/j.1365-2958.2006.05173.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bacterial capsules are not only important virulence factors, but also provide attachment sites for bacteriophages that possess capsule degrading enzymes as tailspike proteins. To gain insight into the evolution of these specialized viruses, we studied a panel of tailed phages specific for Escherichia coli K1, a neuroinvasive pathogen with a polysialic acid capsule. Genome sequencing of two lytic K1-phages and comparative analyses including a K1-prophage revealed that K1-phages did not evolve from a common ancestor. By contrast, each phage is related to a different progenitor type, namely T7-, SP6-, and P22-like phages, and gained new host specificity by horizontal uptake of an endosialidase gene. The new tailspikes emerged by combining endosialidase domains with the capsid binding module of the respective ancestor. For SP6-like phages, we identified a degenerated tailspike protein which now acts as versatile adaptor protein interconnecting tail and newly acquired tailspikes and demonstrate that this adapter utilizes an N-terminal undecapeptide interface to bind otherwise unrelated tailspikes. Combining biochemical and sequence analyses with available structural data, we provide new molecular insight into basic mechanisms that allow changes in host specificity while a conserved head and tail architecture is maintained. Thereby, the present study contributes not only to an improved understanding of phage evolution and host-range extension but may also facilitate the on purpose design of therapeutic phages based on well-characterized template phages.
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Affiliation(s)
- Katharina Stummeyer
- Abteilung Zelluläre Chemie, Zentrum Biochemie, Medizinische Hochschule Hannover, Carl-Neuberg-Street 1, 30625 Hannover, Germany
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13
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Kulikova EE, Isaeva AS, Rotkina AS, Manykin AA, Letarov AV. [Diversity and dynamics of bacteriophages in horse feces]. Mikrobiologiia 2007; 76:271-8. [PMID: 17583225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The complex cellulolytic microbial community of the horse intestines is a convenient model for studying the ecology of bacteriophages in natural habitats. Unlike the rumen of the ruminants, this community of the equine large intestine is not subjected to digestion. The inner conditions of the horse gut are much more stable in comparison to other mammals, due to the fact that the horse diet remains almost unchanged and the intervals between food consumption and defecation are much shorter than the whole digestive cycle. The results of preliminary analysis of the structure and dynamics of the viral community of horse feces, which combines direct and culture methods, are presented. In horse fecal samples, we detected more than 60 morphologically distinct phage types, the majority of which were present as a single phage particle. This indicates that the community includes no less than several hundreds of phage types. Some phage types dominated and constituted 5-11% of the total particle count each. The most numerous phage type had an unusual morphology: the tails of its members were extremely long (about 700 nm), flexible, and irretractable, while their heads were 100 nm in diameter. Several other phage types with similar but not identical properties were detected. The total coliphage plaque count of the samples taken from three animals revealed significant fluctuations in the phage titers. During the observation time, the maximum titer ranged within four orders of magnitude (10(3)-10(7) plaque forming units (PFU)/g); the minimum titer ranged within two orders of magnitude. The samples contained two to five morphologically distinct and potentially competitive coliphage types, specific to a single Escherichia coli strain.
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14
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García-Aljaro C, Muniesa M, Jofre J, Blanch AR. Newly identified bacteriophages carrying the stx2g Shiga toxin gene isolated from Escherichia coli strains in polluted waters. FEMS Microbiol Lett 2006; 258:127-35. [PMID: 16630267 DOI: 10.1111/j.1574-6968.2006.00213.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Shiga toxin-converting bacteriophages are the main vehicle involved in horizontal transmission of stx1 and stx2 genes, which has led to the current spread of stx genes among a high number of Escherichia coli serotypes and other enterobacteria. Several stx gene variants have been described, although some of the variants have never been isolated from inducible bacteriophages. In this study, two stx2g-carrying bacteriophages induced from two different E. coli O2:H25 strains isolated from different wastewater samples were characterized. These bacteriophages when transduced into Shigella sonnei retained their ability to produce Stx2 protein. They had similar but not identical DNA restriction patterns, and similar host ranges. Electron microscopy studies showed that they had isometric capsids with short tails, which resembled phage 933W. However, DNA cross-hybridization studies showed that phage 933W was not closely related to stx2g bacteriophages. This first description of stx2g-carrying bacteriophages enlarges the list of stx-carrying bacteriophages involved in horizontal transmission of stx genes in the environment.
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15
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Muniesa M, Blanco JE, de Simón M, Serra-Moreno R, Blanch AR, Jofre J. Diversity of stx2 converting bacteriophages induced from Shiga-toxin-producing Escherichia coli strains isolated from cattle. Microbiology (Reading) 2005; 150:2959-2971. [PMID: 15347754 DOI: 10.1099/mic.0.27188-0] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The presence of bacteriophages encoding Shiga toxin 2 (stx(2) phages) was analysed in 168 strains of Shiga-toxin-producing Escherichia coli (STEC) isolated from cattle. Following mitomycin C induction, strains carrying stx(2) phages were screened by plaque blot and hybridization with an stx(2)A-probe. In the stx(2)-phage-carrying strains, the amounts of phage production, phage DNA extracted and Stx(2) produced after induction were assessed. The induced stx(2) phages were characterized morphologically and genetically. Assays to obtain lysogens from different strains were also carried out and phages induced from the lysogens were compared with those induced from the STEC isolates. Results indicated that 18 % of the strains carried an inducible stx(2) phage. Most of them showed a direct relationship between phage induction and toxin production. Each strain carried only one inducible stx(2) phage, although a few strains had two copies of the stx(2) in the chromosome. The stx(2) phages showed diverse morphology and a wide variability in their genome. Assays to obtain lysogens showed that not all the phages were transduced with the same frequency and only six lysogens were obtained. Phages in the lysogens were the same as those induced from their respective initial STEC host strains, although the induction and relative toxin production of the lysogens varied. Most phages carried the stx(2) gene, while a few carried stx(2) variants. Infectivity of the phages depended on the different hosts, although O157 : H7 was preferentially infected by phages induced from O157 strains. The results show that inducible stx(2) phages are common among STEC of animal origin and that they may enhance the spread of stx(2).
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Affiliation(s)
- Maite Muniesa
- Department of Microbiology, University of Barcelona, Diagonal 645, E-08028 Barcelona, Spain
| | - Jesus E Blanco
- Laboratorio de Referencia de E. coli (LREC), Departamento de Microbiología y Parasitología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain
| | - Merce de Simón
- Servei Microbiologia, Laboratori de l'Agència de Salut Pública de Barcelona, Drassanes 13, E-08001 Barcelona, Spain
| | - Ruth Serra-Moreno
- Department of Microbiology, University of Barcelona, Diagonal 645, E-08028 Barcelona, Spain
| | - Anicet R Blanch
- Department of Microbiology, University of Barcelona, Diagonal 645, E-08028 Barcelona, Spain
| | - Juan Jofre
- Department of Microbiology, University of Barcelona, Diagonal 645, E-08028 Barcelona, Spain
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16
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Darsavelidze MA, Chanishvili TG. [Characterization of Escherichia coli donor-specific RNA-containing bacteriophages]. Zh Mikrobiol Epidemiol Immunobiol 2005:86-8. [PMID: 15881950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The biological properties of 9 clones of Ri bacteriophages isolated from sewage water in 1981 were studied. On the basis of the activity of Ri phages with respect to E. coli donor-specific strains K12, the type of negative colonies, the ultrastructure of the virion and its sizes, adsorption on the pili of host cells, the latent period, the amount of harvest obtained from one infected cell, the clones under study were classified with small spherical RNA-bacteriophages. The neutralization of Ri phages with antiphage sera to standard phages f2 and fr made it possible to classify them with the first serological group and to divide them into 3 subgroups.
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17
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Abstract
Shiga toxin (Stx) genes in Stx producing Escherichia coli (STEC) are encoded in prophages of the lambda family, such as H-19B. The subpopulation of STEC lysogens with induced prophages has been postulated to contribute significantly to Stx production and release. To study induced STEC, we developed a selectable in vivo expression technology, SIVET, a reporter system adapted from the RIVET system. The SIVET lysogen has a defective H-19B prophage encoding the TnpR resolvase gene downstream of the phage PR promoter and a cat gene with an inserted tet gene flanked by targets for the TnpR resolvase. Expression of resolvase results in excision of tet, restoring a functional cat gene; induced lysogens survive and are chloramphenicol resistant. Using SIVET we show that: (i) approximately 0.005% of the H-19B lysogens are spontaneously induced per generation during growth in LB. (ii) Variations in cellular physiology (e.g. RecA protein) rather than in levels of expressed repressor explain why members of a lysogen population are spontaneously induced. (iii) A greater fraction of lysogens with stx encoding prophages are induced compared to lysogens with non-Stx encoding prophages, suggesting increased sensitivity to inducing signal(s) has been selected in Stx encoding prophages. (iv) Only a small fraction of the lysogens in a culture spontaneously induce and when the lysogen carries two lambdoid prophages with different repressor/operators, 933W and H-19B, usually both prophages in the same cell are induced.
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Affiliation(s)
- Jonathan Livny
- Program in Cell and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, USA
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18
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Goodridge L, Gallaccio A, Griffiths MW. Morphological, host range, and genetic characterization of two coliphages. Appl Environ Microbiol 2003; 69:5364-71. [PMID: 12957924 PMCID: PMC194992 DOI: 10.1128/aem.69.9.5364-5371.2003] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2002] [Accepted: 07/03/2003] [Indexed: 11/20/2022] Open
Abstract
Two coliphages, AR1 and LG1, were characterized based on their morphological, host range, and genetic properties. Transmission electron microscopy showed that both phages belonged to the Myoviridae; phage particles of LG1 were smaller than those of AR1 and had an isometric head 68 nm in diameter and a complex contractile tail 111 nm in length. Transmission electron micrographs of AR1 showed phage particles consisting of an elongated isometric head of 103 by 74 nm and a complex contractile tail 116 nm in length. Both phages were extensively tested on many strains of Escherichia coli and other enterobacteria. The results showed that both phages could infect many serotypes of E. coli. Among the enterobacteria, Proteus mirabilis, Shigella dysenteriae, and two Salmonella strains were lysed by the phages. The genetic material of AR1 and LG1 was characterized. Phage LG1 had a genome size of 49.5 kb compared to 150 kb for AR1. Restriction endonuclease analysis showed that several restriction enzymes could degrade DNA from both phages. The morphological, genome size, and restriction endonuclease similarities between AR1 and phage T4 were striking. Southern hybridizations showed that AR1 and T4 are genetically related. The wide host ranges of phages AR1 and LG1 suggest that they may be useful as biocontrol, therapeutic, or diagnostic agents to control and detect the prevalence of E. coli in animals and food.
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Affiliation(s)
- Lawrence Goodridge
- Canadian Research Institute for Food Safety, Department of Food Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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19
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Muniesa M, de Simon M, Prats G, Ferrer D, Pañella H, Jofre J. Shiga toxin 2-converting bacteriophages associated with clonal variability in Escherichia coli O157:H7 strains of human origin isolated from a single outbreak. Infect Immun 2003; 71:4554-62. [PMID: 12874335 PMCID: PMC166033 DOI: 10.1128/iai.71.8.4554-4562.2003] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Shiga toxin 2 (Stx2)-converting bacteriophages induced from 49 strains of Escherichia coli O157:H7 isolated during a recent outbreak of enterocolitis in Spain were examined in an attempt to identify the variability due to the stx(2)-converting phages. The bacterial isolates were divided into low-, medium-, and high-phage-production groups on the basis of the number of phages released after mitomycin C induction. Low- and medium-phage-production isolates harbored two kinds of phages but released only one of them, whereas high-phage-production isolates harbored only one of the two phages. One of the phages, phi SC370, which was detected only in the isolates with two phages, showed similarities with phage 933W. The second phage, phi LC159, differed from phi SC370 in morphology and DNA structure. When both phages were present in the same bacterial chromosome, as occurred in most of the isolates, only phi SC370 was detected in the supernatants of the induced cultures. If phi LC159 was released, its presence was masked by phi SC370. When phi SC370 was absent, large amounts of phi LC159 were released, suggesting that there was some regulation of phage expression between the two phages. To our knowledge, this is the first description of clonal variability due to phage loss. The higher level of phage production was reflected in the larger amounts of Stx2 toxin produced by the cultures. Some relationship between phage production and the severity of symptoms was observed, and consequently these observations suggest that the virulence of the isolates studied could be related to the variability of the induced stx(2)-converting phages.
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Affiliation(s)
- Maite Muniesa
- Department of Microbiology, University of Barcelona, E-08028 Barcelona, Spain
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20
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Abstract
Transmission electron micrographs of Escherichia coli cells induced by cloned lysis genes from RNA bacteriophages GA (group A-II) and SP (group B-IV) revealed various morphological aspects of intermediates of lysing cells. Cells induced by the SP lysis gene became stretched and also tapered in shape and fragmentation of parts of the cells had also occurred. Cells induced by the GA lysis gene showed many ballooning structures on the cell surfaces and others leaked material through the cell wall. Some balloon-like structures also appeared on the surfaces of cells induced by the cloned lysis gene of RNA phage SP and material also appeared to be leaking through the cell wall in the photographs. The lysing cells observed by transmission electron microscopy showed various morphological aspects of intermediates of the lysing process.
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Affiliation(s)
- Tohru Nishihara
- Department of Biochemistry, Kawasaki Medical School, Kurashiki, Japan1
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21
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Abstract
A coliphage named 63D, isolated previously, associated sialidase as a component of phage particles. In order to localize the enzyme in phage particles, phages were partially destroyed by sonication, and the disrupted particles were size fractionated using a sucrose density gradient. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, enzyme assay and electron micrography of the fractions revealed the enzyme to be composed of four identical subunits with a molecular mass of 90 kDa, and the subunits were cross-linked by disulfide bonds. Electron micrographic observation indicated that six enzyme molecules were localized in a phage tail plate as a hexagonal array.
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Affiliation(s)
- Y Machida
- Department of Biotechnology, Graduate School of Bioengineering, Nagoya University, Chikusa-ku, Nagoya, Japan
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22
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Muniesa M, Lucena F, Jofre J. Study of the potential relationship between the morphology of infectious somatic coliphages and their persistence in the environment. J Appl Microbiol 1999; 87:402-9. [PMID: 10540243 DOI: 10.1046/j.1365-2672.1999.00833.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The proportions of different morphological types of infectious somatic coliphages were determined in faecally polluted freshwaters. Myoviridae, followed by Siphoviridae, were the most frequently isolated morphological types in raw sewage, treated sewage and river water collected a few metres downstream from a sewage outfall. However, in river water collected further downstream from the pollution point, in river water after 'in situ' inactivation experiments and in chlorinated raw and treated sewage significant changes in the proportions of the different somatic coliphage morphological types occurred. In all cases, Siphoviridae, especially those with flexible and curled tails, became more abundant to the detriment of Myoviridae.
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Affiliation(s)
- M Muniesa
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Spain
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23
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Plunkett G, Rose DJ, Durfee TJ, Blattner FR. Sequence of Shiga toxin 2 phage 933W from Escherichia coli O157:H7: Shiga toxin as a phage late-gene product. J Bacteriol 1999; 181:1767-78. [PMID: 10074068 PMCID: PMC93574 DOI: 10.1128/jb.181.6.1767-1778.1999] [Citation(s) in RCA: 305] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/1998] [Accepted: 01/06/1999] [Indexed: 11/20/2022] Open
Abstract
Lysogenic bacteriophages are major vehicles for the transfer of genetic information between bacteria, including pathogenicity and/or virulence determinants. In the enteric pathogen Escherichia coli O157:H7, which causes hemorrhagic colitis and hemolytic-uremic syndrome, Shiga toxins 1 and 2 (Stx1 and Stx2) are phage encoded. The sequence and analysis of the Stx2 phage 933W is presented here. We find evidence that the toxin genes are part of a late-phage transcript, suggesting that toxin production may be coupled with, if not dependent upon, phage release during lytic growth. Another phage gene, stk, encodes a product resembling eukaryotic serine/threonine protein kinases. Based on its position in the sequence, Stk may be produced by the prophage in the lysogenic state, and, like the YpkA protein of Yersinia species, it may interfere with the signal transduction pathway of the mammalian host. Three novel tRNA genes present in the phage genome may serve to increase the availability of rare tRNA species associated with efficient expression of pathogenicity determinants: both the Shiga toxin and serine/threonine kinase genes contain rare isoleucine and arginine codons. 933W also has homology to lom, encoding a member of a family of outer membrane proteins associated with virulence by conferring the ability to survive in macrophages, and bor, implicated in serum resistance.
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MESH Headings
- Attachment Sites, Microbiological/genetics
- Bacterial Toxins/genetics
- Base Sequence
- Coliphages/genetics
- Coliphages/ultrastructure
- DNA, Viral/genetics
- Escherichia coli O157/genetics
- Escherichia coli O157/pathogenicity
- Escherichia coli O157/virology
- Genes, Bacterial
- Genes, Viral
- Humans
- Microscopy, Electron
- Molecular Sequence Data
- Nucleic Acid Conformation
- Open Reading Frames
- Operator Regions, Genetic
- Promoter Regions, Genetic
- RNA, Transfer/chemistry
- RNA, Transfer/genetics
- RNA, Viral/chemistry
- RNA, Viral/genetics
- Shiga Toxins
- Terminator Regions, Genetic
- Virulence/genetics
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Affiliation(s)
- G Plunkett
- Laboratory of Genetics, University of Wisconsin, Madison, Wisconsin 53706, USA
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24
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Matsuno M, Takeuchi H, Overman SA, Thomas GJ. Orientations of tyrosines 21 and 24 in coat subunits of Ff filamentous virus: determination by Raman linear intensity difference spectroscopy and implications for subunit packing. Biophys J 1998; 74:3217-25. [PMID: 9635775 PMCID: PMC1299662 DOI: 10.1016/s0006-3495(98)78028-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Virions of the Ff group of bacteriophages (fd, f1, M13) are morphologically identical filaments (approximately 6-nm diameter x approximately 880-nm length) in which a covalently closed, single-stranded DNA genome is sheathed by approximately 2700 copies of a 50-residue alpha-helical subunit (pVIII). Orientations of pVIII tyrosines (Tyr21 and Tyr24) with respect to the filament axis have been determined by Raman linear intensity difference (RLID) spectroscopy of flow-oriented mutant virions in which the tyrosines were independently mutated to methionine. The results show that the twofold axis of the phenolic ring (C1-C4 line) of Tyr21 is inclined at 39.5 +/- 1.4 degrees from the virion axis, and that of Tyr24 is inclined at 43.7 +/- 0.6 degrees. The orientation determined for the Tyr21 phenol ring is close to that of a structural model previously proposed on the basis of fiber x-ray diffraction results (Protein Data Bank, identification code 1IFJ). On the other hand, the orientation determined for the Tyr24 phenol ring differs from the diffraction-based model by a 40 degrees rotation about the Calpha-Cbeta bond. The RLID results also indicate that each tyrosine mutation does not greatly affect the orientation of either the remaining tyrosine or single tryptophan (Trp26) of pVIII. On the basis of these results, a refined model is proposed for the coat protein structure in Ff.
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Affiliation(s)
- M Matsuno
- Pharmaceutical Institute, Tohoku University, Sendai, Japan
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25
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Ackermann HW, DuBow MS, Gershman M, Karska-Wysocki B, Kasatiya SS, Loessner MJ, Mamet-Bratley MD, Regué M. Taxonomic changes in tailed phages of enterobacteria. Arch Virol 1997; 142:1381-90. [PMID: 9267450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Out of 136 new phages, 80 (59%) are classified into 23 species according to morphology and physicochemical properties. Six new species are described and species beta 4, from a previous classification scheme, is renamed T1. The morphology of 36 phage species is schematically represented.
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Affiliation(s)
- H W Ackermann
- Félix d'Hérelle Reference Center for Bacterial Viruses, Department of Microbiology, Faculty of Medicine, Laval University, Quebec, Canada
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26
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Abstract
A billion-clone library of filamentous phage with different surface structures ("landscapes') was generated by fusing random octapeptides to the N-terminus of all 4000 copies of the major coat protein. Such a "landscape library' might include clones exhibiting emergent properties that inhere in the entire surface architecture, not in the peptides by themselves. Because the diverse surface landscapes are displayed on viable phage, they can be surveyed for exceedingly rare functions using microbiological selection methods. Clones with several emergent properties of the sort envisioned were successfully selected, suggesting that landscape libraries have promise as a novel source of nanomaterials with exploitable surface properties.
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Affiliation(s)
- V A Petrenko
- State Research Center for Virology and Biotechnology Vector, Novosibirsk, Russia
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27
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Abstract
We show that all minor coat proteins of phage f1 are integral inner membrane proteins prior to assembly. Hence all phage structural and morphogenetic proteins are localized in the membrane of the infected cell, consistent with models of phage assembly in which morphogenesis is coincident with phage extrusion. Our data suggest that the minor coat proteins, pVI and pIII, are already associated with the major coat protein, pVIII, in the membrane. On the other hand pVI and pIII are not recovered as a complex from the membrane, even though experiments with dissociated phage show they are associated in phage. The minor coat proteins, pVII and pVIII, are also associated in phage. With the use of sera directed against the minor proteins, we show that the minor coat protein, pIX, is accessible in intact phage, but pVI and pVII are not. Consistent with earlier results, the attachment protein, pIII, clearly is exposed on the phage exterior. Infected cells contain about ten times more pVII and pIX than is incorporated into phage.
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Affiliation(s)
- H Endemann
- Rockefeller University, New York, NY 10021, USA
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28
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Marvik OJ, Jacobsen E, Dokland T, Lindqvist BH. Bacteriophage P2 and P4 morphogenesis: assembly precedes proteolytic processing of the capsid proteins. Virology 1994; 205:51-65. [PMID: 7975237 DOI: 10.1006/viro.1994.1619] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Several of the structural proteins of phage P2 and its satellite P4 undergo proteolytic processing during development of mature phage particles. Here, we report that uncleaved shell protein, gpN, is present in immature capsids of both P2 and P4, showing that assembly precedes processing. This excludes the possibility that processing of gpN is involved in capsid size determination. We also find that N*, the fully processed version of gpN, produced from a plasmid, can assemble into both P2- and P4-sized particles, implying that the amino-terminal end of gpN is not required for assembly initiation nor for the formation of a T = 4 shell. As may be expected for a scaffolding protein, we find that gpO coexists with gpN in immature P2, as well as P4, capsids. This result supports the conclusion that gpO is required for both phages and strongly suggests that the O derivative, h7 (found in mature capsids), results from proteolytic cleavage after gpN/gpO coassembly.
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Affiliation(s)
- O J Marvik
- Institute of Biology, University of Oslo, Blindern, Norway
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29
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Abstract
The portal structure has been implicated in several aspects of the bacteriophage life cycle, including capsid assembly initiation and DNA packaging. Here we present evidence that P2 gene Q codes for the P2 and P4 portal protein. First, microsequencing shows that capsid protein h6 is derived from gpQ, most probably by proteolytic cleavage. Second, antibodies against gpQ bind to the portal structure in disrupted P2 phage virions, as observed by electron microscopy. Third, gpQ partially purified from an overexpressing plasmid assembles into portal-like structures. We also show by microsequencing that capsid protein h7 is encoded by the P2 scaffold gene, O, and is probably derived from gpO by proteolytic cleavage. Previous work has demonstrated processing of the major capsid protein. Thus, all essential capsid proteins of P2 and P4 are proteolytically cleaved during the morphogenetic process.
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Affiliation(s)
- S Rishovd
- Institute of Biology, University of Oslo, Norway
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30
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Müller M, Engel A, Aebi U. Structural and physicochemical analysis of the contractile MM phage tail and comparison with the bacteriophage T4 tail. J Struct Biol 1994; 112:11-31. [PMID: 8031638 DOI: 10.1006/jsbi.1994.1003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The three-dimensional (3-D) structure of the bacteriophage MM extended tail has been determined from electron micrographs of negatively stained specimens and compared with 3-D models of coprocessed extended bacteriophage T4 tails. Accordingly, the phage MM extended tail exhibits an axial repeat of 3.8 nm and can be indexed according to the integer helical selection rule l = -3n + 7m (n = 6n') compared to 4.1 nm and l = -2n + 7m (n = 6n') for the T4 phage tail. Compared to the T4 tail sheath, which reveals a stacked-disk-like appearance, the MM tail exhibits a more open structure, yielding an arrow-head-like appearance. Although the phage MM extended tail sheath is more stable than the T4 tail sheath under low-ionic-strength conditions, various chemical treatments of the MM tail sheath revealed responses, notably disassembly and contraction, similar to those previously described for the T4 tail sheath. Extended tails and their structural components contained in phage lysates or prepared by chemical degradation were compared in the EM, and the mass-per-length values of extended tails and tail tubes were determined by quantitative scanning transmission electron microscopy and compared to the corresponding values computed from the respective 3-D mass density maps. Accordingly, masses of 111 and 135 kDa/nm were obtained for the MM and T4 phage tail sheaths, respectively, with the corresponding tail tubes calculated at 19.3 and 25.5 kDa/nm, respectively. Although negative staining and freeze drying/metal shadowing of the two tails revealed different extended tail sheath structures, freeze-dried/metal-shadowed specimens of their contracted tails revealed very similar 6-fold symmetric axial repeats, with the subunits arranged on a pseudo-12-fold symmetric surface lattice following the integer helical selection rule l = n + 11m. In both cases tail contraction started at the baseplate and propagated headward as a wave forming a contraction gradient with a sharp boundary.
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Affiliation(s)
- M Müller
- M.E. Müller-Institute for Microscopy, University of Basel, Switzerland
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31
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Pushko P, Kozlovskaya T, Sominskaya I, Brede A, Stankevica E, Ose V, Pumpens P, Grens E. Analysis of RNA phage fr coat protein assembly by insertion, deletion and substitution mutagenesis. Protein Eng 1993; 6:883-91. [PMID: 8309936 DOI: 10.1093/protein/6.8.883] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A structure-function analysis of the icosahedral RNA bacteriophage fr coat protein (CP) assembly was undertaken using linker-insertion, deletion and substitution mutagenesis. Mutations were specifically introduced into either pre-existing or artificially created restriction enzyme sites within fr CP gene expressed in Escherichia coli from a recombinant plasmid. This directs synthesis of wild type protein that undergoes self-assembly and forms capsid-like particles indistinguishable morphologically and immunologically from native phage particles. A series of fr CP variants containing sequence alterations in the regions which are (i) exposed on the external surface of capsid or (ii) located on the contacting areas between CP subunits were obtained and their assembly properties investigated. The majority of mutants demonstrated reduction of assembly ability and formed either CP dimers (mutations at residues 2, 10, 63 or 129) or both dimer and capsid structures (residue 2 or 69). The exceptions were variants demonstrating normal assembly and containing insertions at residues 2, 50 or 129 of the fr CP. A third type of assembled structure was formed by a variant with a single amino acid substitution I104T. The alpha A-helix region (residues 97-111) is particularly sensitive to mutation and any alteration in this region decreases accumulation of mutant protein in E. coli. The relative contributions of particular fr CP domains in maintenance of capsid structural integrity as well as the possible capsid assembly mechanism are discussed.
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Affiliation(s)
- P Pushko
- Institute of Molecular Biology, Latvian Academy of Sciences, Riga
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32
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Abstract
Temperate coliphage P2 and satellite phage P4 have icosahedral capsids and contractile tails with side tail fibers. Because P4 requires all the capsid, tail, and lysis genes (late genes) of P2, the genomes of these phages are in constant communication during P4 development. The P4 genome (11,624 bp) and the P2 genome (33.8 kb) share homologous cos sites of 55 bp which are essential for generating 19-bp cohesive ends but are otherwise dissimilar. P4 turns on the expression of helper phage late genes by two mechanisms: derepression of P2 prophage and transactivation of P2 late-gene promoters. P4 also exploits the morphopoietic pathway of P2 by controlling the capsid size to fit its smaller genome. The P4 sid gene product is responsible for capsid size determination, and the P2 capsid gene product, gpN, is used to build both sizes. The P2 capsid contains 420 capsid protein subunits, and P4 contains 240 subunits. The size reduction appears to involve a major change of the whole hexamer complex. The P4 particles are less stable to heat inactivation, unless their capsids are coated with a P4-encoded decoration protein (the psu gene product). P4 uses a small RNA molecule as its immunity factor. Expression of P4 replication functions is prevented by premature transcription termination effected by this small RNA molecule, which contains a sequence that is complementary to a sequence in the transcript that it terminates.
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Affiliation(s)
- B H Lindqvist
- Biologisk Institutt og Bioteknologisenteret i Oslo, Universitetet i Oslo, Norway
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33
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Stockley PG, Stonehouse NJ, Walton C, Walters DA, Medina G, Macedo JM, Hill HR, Goodman ST, Talbot SJ, Tewary HK. Molecular mechanism of RNA-phage morphogenesis. Biochem Soc Trans 1993; 21 ( Pt 3):627-33. [PMID: 8224478 DOI: 10.1042/bst0210627] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- P G Stockley
- Department of Genetics, University of Leeds, U.K
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34
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Petter JG, Vimr ER. Complete nucleotide sequence of the bacteriophage K1F tail gene encoding endo-N-acylneuraminidase (endo-N) and comparison to an endo-N homolog in bacteriophage PK1E. J Bacteriol 1993; 175:4354-63. [PMID: 8331067 PMCID: PMC204875 DOI: 10.1128/jb.175.14.4354-4363.1993] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Endo-N-acylneuraminidase (endo-N) is a phage-encoded depolymerase that degrades the alpha (2-8)-linked polysialic acid chains of K1 serotypes of Escherichia coli and vertebrate neural cell adhesion molecules. We have determined the DNA sequence of the bacteriophage K1F tail protein structural gene, which codes for a polypeptide of 920 residues. Purification of the tail protein yields a 102-kDa species upon denaturing gel electrophoresis and detection by Western immunoblot analysis. An identical polypeptide was detected by Western blot analysis of K1F virions. Peptide sequencing confirmed that the open reading frame determined by nucleotide sequencing encodes endo-N. Immunoelectron microscopy with neutralizing antibodies raised against the depolymerase confirmed that endo-N is a component of the K1F tail apparatus. Antibodies in the serum cross-reacted with endo-N from another K1-specific phage, PK1E, demonstrating the presence of shared epitopes. Homology between K1F and PK1E endo-N was confirmed by Southern, Northern (RNA), and Western blot analyses. The endo-N amino-terminal domain is homologous to the amino termini of phage T7 and T3 tail proteins, indicating by analogy that this domain functions in attachment of endo-N to the K1F virion's head. A central domain of 495 residues has weak similarity to sea urchin aryl sulfatase, suggesting that this region may contain the endo-N catalytic site. Failure to detect homology between the PK1E homolog and the carboxy-terminal domain of K1F endo-N is consistent with the central domain's involvement in binding and catalysis of polysialic acid. These results provide the initial molecular and genetic description of polysialic acid depolymerase, which has so far been detected only in K1-specific phage.
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Affiliation(s)
- J G Petter
- Department of Veterinary Pathobiology, University of Illinois, Urbana-Champaign 61801
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35
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Da Poian AT, Oliveira AC, Gaspar LP, Silva JL, Weber G. Reversible pressure dissociation of R17 bacteriophage. The physical individuality of virus particles. J Mol Biol 1993; 231:999-1008. [PMID: 8515477 DOI: 10.1006/jmbi.1993.1347] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In the absence of urea, pressures up to 2.5 kbar promote only 10% dissociation of the whole particles of R17 bacteriophage. In the presence of concentrations of urea between 1.0 and 5.0 M, pressure promotes complete, reversible dissociation of the virus particles. At the lower urea concentrations reversible dissociation of R17 virus particles shows no dependence on protein concentration indicating a high degree of heterogeneity of the particles, but higher urea concentrations, 2.5 to 5.0 M, result in progressive restoration of the protein concentration dependence of the pressure dissociation. At still higher urea concentrations, 5.0 to 8.0 M, irreversible dissociation of virus takes place at atmospheric pressure. In contrast, the dissociation of the isolated dimers of the capsid protein was dependent on protein concentration to the extent predicted for a stochastic equilibrium, and dimers were much less stable than the whole virus both to dissociation by pressure or urea. In contradistinction, the reversible whole-virus dissociation observed at urea concentrations below 2.5 M appears to be a typical deterministic equilibrium, without appreciable dynamic exchange between whole particle and subunits during the lengthy experiments. The experiments demonstrate that the "thermodynamic individuality" of the virus particles arises in conformational differences in the assembled viruses, and that there is a direct relation between the stability of the particles and their heterogeneity.
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Affiliation(s)
- A T Da Poian
- Departamento de Bioquimica, Universidade Federal do Rio de Janeiro, Brazil
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36
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Abstract
Strategies for the construction of vehicles for phage display are evaluated here on the basis of structural studies of filamentous bacteriophages. Potential sites for the insertion of foreign peptides into the major coat protein, gp8, of M13 are identified. Currently, the insertion of peptides into gp8 has two basic limitations: all insertion sites that have been used successfully are located within 5 amino acids (aa) of the N terminus, and in virions containing only mutant coat proteins, insertions larger than about 6 aa have not been successfully incorporated. The possible reasons for these limitations are discussed in terms of the structures of gp8 and the minor structural proteins, gp7 and gp9. Potential strategies for overcoming these limitations are outlined. Reasons for the successful incorporation of larger inserts into hybrid phage containing both native and mutant coat proteins are also discussed. The structures of gp6, gp7, and gp9 are described, and it is concluded that insertion sites in these minor proteins are unlikely to have substantial advantages over those currently being used in gp3. The structure of the coat protein of another filamentous phage, Pseudomonas phage Pf1, is also described. Its structure provides a number of clues for the successful design of phage display insertion sites. Because it contains a 7-aa surface loop in the major coat protein, the Pf1 coat protein may have significant advantages over gp8 of M13 as a vehicle for phage display.
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Affiliation(s)
- L Makowski
- Institute of Molecular Biophysics, Florida State University, Tallahassee 32306
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37
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Luo C, Butcher S, Bamford DH. Isolation of a phospholipid-free protein shell of bacteriophage PRD1, an Escherichia coli virus with an internal membrane. Virology 1993; 194:564-9. [PMID: 8503174 DOI: 10.1006/viro.1993.1295] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
PRD1 is a double-stranded DNA virus infecting Escherichia coli and Salmonella typhimurium. It has an icosahedral outer protein capsid which encloses the viral membrane, inside of which resides the phage genome. In this investigation we demonstrate the detergent resistance of the intact virus particles. The membrane of empty DNA-free particles, however, is very sensitive to detergent action. We assume that their sensitivity is due to the access of detergents through a portal structure to the virus interior. Using the anionic detergent sodium dodecyl sulfate, it is possible to obtain a shell structure composed of the major coat protein P3 alone. The treatment of empty particles with the milder nonionic detergents n-octyl beta-D-glucopyranoside and Triton X-100 yielded P3 particles which retained the membrane-associated proteins P7 and P11. Deoxycholic acid treatment yielded shells of intermediate composition between those obtained with the nonionic detergents and sodium dodecyl sulfate.
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Affiliation(s)
- C Luo
- Department of Genetics, University of Helsinki, Finland
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38
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Abstract
In addition to its polarity-suppressing activity, the Psu protein of bacteriophage P4 also serves to stabilize the capsid against heat treatment and binds externally to the phage capsid. However, the heat stability is lost upon purification of the virus, indicating a loss of Psu protein from the capsid. By using three-dimensional reconstruction from cryo-electron micrographs of P4 psu1 amber mutants lacking Psu, and of P4 virions, which have been saturated with Psu protein to regain heat stability, we have determined the position of this protein on the virus surface. Our results are consistent with the hypothesis that the function of Psu is to stabilize the hexameric capsomer assembly.
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Affiliation(s)
- T Dokland
- European Molecular Biology Laboratory, Heidelberg, Germany
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39
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Abstract
The Psu (Polarity suppression) protein of satellite bacteriophage P4 was first characterized as an anti-terminator of transcription termination in Escherichia coli. Psu is also a structural component of mature P4 capsids, where it is present as a decoration protein. Psu is located externally on the capsid surface, and it appears to protect the capsid from loss of DNA through the capsid shell. The ability of Psu to specifically bind to the P4 capsid appears not to be dependent on any P4 specific components such as the capsid protein cleavage products h1 and h2, or P4 DNA. We suggest that Psu binds to the P4 capsid as a result of the special structure of the hexamers in the P4 capsid.
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Affiliation(s)
- M L Isaksen
- Institute of Biology, University of Oslo, Norway
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40
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Abstract
Bacteriophage PRD1, a double-stranded DNA virus infecting Escherichia coli, has a membrane inside the protein capsid. Chemical cross-linking and scanning transmission electron microscopy showed that the multimeric major coat protein (P3) exists in a trimeric form. Cross-linking revealed, in addition, that protein P11, located between the protein coat and the membrane, exists also as a homotrimer. Minor protein P7 was associated with the major coat protein P3. Under nonreducing conditions the infectivity proteins P16 and P18 formed homomultimeric complexes which were dissociated upon addition of 2-mercaptoethanol.
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Affiliation(s)
- C Luo
- Department of Genetics, University of Helsinki, Finland
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41
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Abstract
Electron microscopy in combination with image processing is a powerful method for obtaining structural information on non-crystallized biological macromolecules at the 10-50 A resolution level. The processing of noisy microscopical images requires advanced data processing methodologies in which one must carefully avoid the introduction of any form of bias into the data set. Using a novel multivariate statistical approach to the analysis of symmetry, we studied the structure of the bacteriophage SPP1 portal protein oligomer. This portal structure, ubiquitous in icosahedral bacteriophages which package dsDNA, is located at the site of symmetry mismatch between a 5-fold vertex of the icosahedral shell and the 6-fold symmetric (helical) tail. From previous studies such 'head-to-tail connector' structures were generally accepted to be homododecamers assembled in a 12-fold symmetric ring around a central channel. Using a new analysis methodology we have found that the phage SPP1 portal structure exhibits 13-fold cyclical symmetry: a new point group organization for oligomeric proteins. A model for the DNA packaging mechanism by 13-fold symmetric portal protein assemblies is presented which attributes a coherent functional meaning to their unusual symmetry.
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Affiliation(s)
- P Dube
- Fritz Haber Institut der Max Planck Gesellschaft, Berlin, Germany
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42
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Abstract
The intergenic region in the genome of the Ff class of filamentous phage (comprising strains fl, fd and M13) genome constitutes 8% of the viral genome, and has essential functions in DNA replication and phage morphogenesis. The functional domains of this region may be inserted into separate sites of a plasmid to function independently. Here, we demonstrate the construction of a plasmid containing, sequentially, the origin of (+)-strand synthesis, the packaging signal and a terminator of (+)-strand synthesis. When host cells harboring this plasmid (pLS7) are infected with helper phage they produce a microphage particle containing all the structural elements of the mature, native phage. The microphage is 65 A in diameter and about 500 A long. It contains a 221-base single-stranded circle of DNA coated by about 95 copies of the major coat protein (gene 8 protein).
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Affiliation(s)
- L Specthrie
- Department of Biochemistry and Molecular Biophysics, College of Physicians and Surgeons, Columbia University, New York, NY 10032
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43
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Abstract
A sophisticated water quality monitoring program was established to evaluate virus removal through Denver's 1-million-gal (ca. 4-million-liter)/day Direct Potable Reuse Demonstration Plant. As a comparison point for the reuse demonstration plant, Denver's main water treatment facility was also monitored for coliphage organisms. Through the routine monitoring of the main plant, it was discovered that coliphage organisms were escaping the water treatment processes. Monochloramine residuals and contact times (CT values) required to achieve 99% inactivation were determined for coliphage organisms entering and leaving this conventional water treatment plant. The coliphage tested in the effluent waters had higher CT values on the average than those of the influent waters. CT values established for some of these coliphages suggest that monochloramine alone is not capable of removing 2 orders of magnitude of these specific organisms in a typical water treatment facility. Electron micrographs revealed one distinct type of phage capable of escaping the water treatment processes and three distinct types of phages in all.
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Affiliation(s)
- S W Dee
- Denver Water Department, Colorado 80254
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44
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Glucksman MJ, Bhattacharjee S, Makowski L. Three-dimensional structure of a cloning vector. X-ray diffraction studies of filamentous bacteriophage M13 at 7 A resolution. J Mol Biol 1992; 226:455-70. [PMID: 1640460 DOI: 10.1016/0022-2836(92)90960-r] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Filamentous bacteriophage M13 is a single-stranded DNA phage about 65 A in diameter and 9300 A long. X-ray diffraction studies of magnetically oriented fibers of native, mercury and iodine-labeled phage particles have been used to determine the arrangement of the major coat protein, the gene 8 product, in the virion. The coat protein is made up of a single gently curving alpha-helix extending from approximately Pro6 to near the carboxyl terminus. The axis of the alpha-helix is tilted about 20 degrees from the viral axis and wraps around the axis in a right-handed helical sense. The surface of the virus is made up largely of polar residues in the amino-terminal half of the protein including the segment of alpha-helix extending from Pro6 to Tyr24. The interior surface of the protein coat faces the DNA and consists of an amphipathic helical segment extending from Thr36 to Ser50. The alpha-helices form a tightly packed 15 to 20 A thick cylindrical coat around the DNA. This structural model provides insight into the potential sites for incorporating foreign protein domains that may act as functional binding sites on the surface of M13.
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Affiliation(s)
- M J Glucksman
- Department of Biochemistry and Molecular Biophysics, College of Physicians and Surgeons of Columbia University, New York, NY 10032
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45
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Henry GD, Sykes BD. Assignment of amide 1H and 15N NMR resonances in detergent-solubilized M13 coat protein: a model for the coat protein dimer. Biochemistry 1992; 31:5284-97. [PMID: 1606152 DOI: 10.1021/bi00138a007] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The major coat protein of the filamentous coliphage M13 is a 50-residue integral membrane protein. Detergent-solubilized M13 coat protein is a promising candidate for structure determination by nuclear magnetic resonance methods as the protein can be prepared in large quantities and the protein-containing micelle is reasonably small. Under the conditions of our experiments, SDS-bound coat protein exists as a dimer with an apparent molecular weight of 27,000. Broad lines and poor resolution in the 1H spectrum have led us to adopt an 15N-directed approach, in which the coat protein was labeled both uniformly with 15N and selectively with [alpha-15N]alanine, -glycine, -valine, -leucine, -isoleucine, phenylalanine, -lysine, -tyrosine, and -methionine. Nitrogen resonances were assigned as far as possible using carboxypeptidase digestion, double-labeling, and an independent knowledge of the amide proton exchange rates determined from neighboring assigned 13C-labeled carbonyl carbons. 1H/15N heteronuclear multiple quantum coherence (HMQC) spectroscopy of both uniform and site-selectively-labeled proteins subsequently correlated amide nitrogen with amide proton chemical shifts, and the assignments were completed sequentially from homonuclear NOESY and HMQC-NOESY spectra. The most slowly exchanging amide protons were shown to occur in a continuous stretch extending from methionine-28 to phenylalanine-42. This sequence includes most of the resonances of the hydrophobic core, although it is shifted toward the C-terminal end of the protein. Strong NH to NH (i,i+1) nuclear Overhauser enhancements are a feature of the coat protein, which appears to be largely helical. Between 20 and 25 residues give rise to 2 juxtaposed resonances which can be seen clearly in the HMQC spectrum of uniform 15N-labeled coat protein. These residues are concentrated in a region extending from the beginning of the membrane-spanning sequence through to the disordered region near the C-terminus. We propose that dodecyl sulfate-bound M13 coat protein consists of two independent domains, an N-terminal helix which is in a state of moderately fast dynamic flux and a long, stable, C-terminal membrane-spanning helix, which undergoes extensive interactions with a second monomer. Amide 1H chemical shifts are consistent with this picture; in addition, a marked periodicity is observed at the C-terminal end of the molecule.
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Affiliation(s)
- G D Henry
- Department of Biochemistry, University of Alberta, Edmonton, Canada
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46
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Abstract
We show that the product of the polarity suppression (psu) gene from bacteriophage P4 associates with P4 capsids. This association can occur when Psu is (i) provided in vivo from the P4 genome or from a plasmid or (ii) provided in vitro by mixing viable phage particles with Psu protein. Psu is unable to associate with the larger capsid of P4's helper phage P2. Discrimination of the P4 and P2 capsids by Psu appears to be independent of the presence of the P4 genome in the capsid, since P2 size capsids filled with P4 DNA cannot accommodate Psu association. P4 psu particles devoid of Psu are less stable than P4 particles carrying Psu. These results indicate that, in addition to its antitermination activity at Rho-dependent terminators, Psu is also a decoration protein that stabilizes the P4 capsids.
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Affiliation(s)
- M L Isaksen
- Institute of Biology, University of Oslo, Norway
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47
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Abstract
Plasmid p15B and the genome of bacteriophage P1 are closely related, but their site-specific DNA inversion systems, Min and Cin, respectively, do not have strict structural homology. Rather, the complex Min system represents a substitution of a Cin-like system into an ancestral p15B genome. The substituting sequences of both the min recombinase gene and the multiple invertible DNA segments of p15B are, respectively, homologous to the pin recombinase gene and to part of the invertible DNA of the Pin system on the defective viral element e14 of Escherichia coli K-12. To map the sites of this substitution, the DNA sequence of a segment adjacent to the invertible segment in the P1 genome was determined. This, together with already available sequence data, indicated that both P1 and p15B had suffered various sequence acquisitions or deletions and sequence amplifications giving rise to mosaics of partially related repeated elements. Data base searches revealed segments of homology in the DNA inversion regions of p15B, e14, and P1 and in tail fiber genes of phages Mu, T4, P2, and lambda. This result suggest that the evolution of phage tail fiber genes involves horizontal gene transfer and that the Min and Pin regions encode tail fiber genes. A functional test proved that the p15B Min region carries a tail fiber operon and suggests that the alternative expression of six different gene variants by Min inversion offers extensive host range variation.
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Affiliation(s)
- H Sandmeier
- Abteilung Mikrobiologie, Universität Basel, Switzerland
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48
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Abstract
Short-term (15-min-duration) and long-term (5- to 6-day-duration) test procedures have been developed for determining the efficiency of the removal of bacteriophage phi X174 by air-sterilizing filters. These procedures were sensitive enough to measure a 10(8)-fold reduction in the number of bacteriophage. A filter commonly used in industrial air sterilizations (Domnick-Hunter Bio-X borosilicate glass) effected a 10(8)-fold removal of viable phage in both short-term and long-term tests. A prototype low-flux, hollow-fiber membrane gave similar results; however, a prototype high-flux, hollow-fiber membrane removed only about 99.999% of the bacteriophage in short-term tests.
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Affiliation(s)
- M L Rapp
- Department of Biology, University of Missouri-St. Louis 63121
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49
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Abstract
Fiber diffraction studies are used to demonstrate that changes in the helical symmetry of the protein coat of filamentous bacterial viruses fd and M13 are correlated with changes in the surface charge. Comparison of the structure of M13 and fd at pH 2 and 8 indicate that surface charge affects both the helical symmetry and flexibility of the virions. The changes in helical symmetry are similar in magnitude to that observed in the Pseudomanas phage Pf1 and probably reflect an inocuous side effect of the particle flexibility required for protection of the virus particles from damage due to shear. The magnitude of the observed changes in helical symmetry appears to be limited to that which can occur without repacking of the interfaces between the alpha-helices making up the viral protein coat.
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Affiliation(s)
- S Bhattacharjee
- Department of Biochemistry and Molecular Biophysics, College of Physicians and Surgeons, Columbia University, New York, New York 10032
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Reynaud A, Cloastre L, Bernard J, Laveran H, Ackermann HW, Licois D, Joly B. Characteristics and diffusion in the rabbit of a phage for Escherichia coli 0103. Attempts to use this phage for therapy. Vet Microbiol 1992; 30:203-12. [PMID: 1532681 DOI: 10.1016/0378-1135(92)90114-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A bacteriophage for Escherichia coli 0103 was isolated during a study on E. coli diarrhoea in intensive breeding units of rabbits. The phage had an isometric head and a short tail and resembled coliphage N4 (Podoviridae). It had a very narrow host range and seemed to be specific for serogroup 0103, suggesting that it might be used for preliminary identification of E. coli strains of this serogroup instead of the usual slide agglutination. In view of its possible use as a therapeutic phage, we investigated its dissemination in rabbit organs after oral administration. The phage persisted in the spleen for at least 12 days. However, in vivo studies showed that this phage and a mixture of more virulent phages for E. coli 0103 were ineffective in preventing disease in rabbits inoculated with an enteropathogenic strain of E. coli 0103.
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Affiliation(s)
- A Reynaud
- Puy-de-Dôme Departmental Veterinary Laboratory, Lempdes, France
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