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Babkin IV, Tikunov AY, Baykov IK, Morozova VV, Tikunova NV. Genome Analysis of Epsilon CrAss-like Phages. Viruses 2024; 16:513. [PMID: 38675856 PMCID: PMC11054128 DOI: 10.3390/v16040513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/28/2024] Open
Abstract
CrAss-like phages play an important role in maintaining ecological balance in the human intestinal microbiome. However, their genetic diversity and lifestyle are still insufficiently studied. In this study, a novel CrAssE-Sib phage genome belonging to the epsilon crAss-like phage genomes was found. Comparative analysis indicated that epsilon crAss-like phages are divided into two putative genera, which were proposed to be named Epsilonunovirus and Epsilonduovirus; CrAssE-Sib belongs to the former. The crAssE-Sib genome contains a diversity-generating retroelement (DGR) cassette with all essential elements, including the reverse transcriptase (RT) and receptor binding protein (RBP) genes. However, this RT contains the GxxxSP motif in its fourth domain instead of the usual GxxxSQ motif found in all known phage and bacterial DGRs. RBP encoded by CrAssE-Sib and other Epsilonunoviruses has an unusual structure, and no similar phage proteins were found. In addition, crAssE-Sib and other Epsilonunoviruses encode conserved prophage repressor and anti-repressors that could be involved in lysogenic-to-lytic cycle switches. Notably, DNA primase sequences of epsilon crAss-like phages are not included in the monophyletic group formed by the DNA primases of all other crAss-like phages. Therefore, epsilon crAss-like phage substantially differ from other crAss-like phages, indicating the need to classify these phages into a separate family.
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Affiliation(s)
- Igor V. Babkin
- Federal State Public Scientific Institution «Institute of Chemical Biology and Fundamental Medicine», Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.Y.T.); (I.K.B.); (V.V.M.)
| | - Artem Y. Tikunov
- Federal State Public Scientific Institution «Institute of Chemical Biology and Fundamental Medicine», Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.Y.T.); (I.K.B.); (V.V.M.)
| | - Ivan K. Baykov
- Federal State Public Scientific Institution «Institute of Chemical Biology and Fundamental Medicine», Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.Y.T.); (I.K.B.); (V.V.M.)
- Shared Research Facility “Siberian Circular Photon Source” (SRF “SKIF”) of Boreskov Institute of Catalysis SB RAS, 630090 Novosibirsk, Russia
| | - Vera V. Morozova
- Federal State Public Scientific Institution «Institute of Chemical Biology and Fundamental Medicine», Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.Y.T.); (I.K.B.); (V.V.M.)
| | - Nina V. Tikunova
- Federal State Public Scientific Institution «Institute of Chemical Biology and Fundamental Medicine», Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.Y.T.); (I.K.B.); (V.V.M.)
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Bhardwaj K, Garg A, Pandey AD, Sharma H, Kumar M, Vrati S. Insights into the human gut virome by sampling a population from the Indian subcontinent. J Gen Virol 2022; 103. [PMID: 35951476 DOI: 10.1099/jgv.0.001774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Gut virome plays an important role in human physiology but remains poorly understood. This study reports an investigation of the human gut DNA-virome of a previously unexplored ethnic population through metagenomics of faecal samples collected from individuals residing in Northern India. Analysis shows that, similar to the populations investigated earlier, majority of the identified virome belongs to bacteriophages and a smaller fraction (<20 %) consists of viruses that infect animals, archaea, protists, multiple domains or plants. However, crAss-like phages, in this population, are dominated by the genera VI, VII and VIII. Interestingly, it also reveals the presence of a virus family, Sphaerolipoviridae, which has not been detected in the human gut earlier. Viral families, Siphoviridae, Myoviridae, Podoviridae, Microviridae, Herelleviridae and Phycodnaviridae are detected in all of the analysed individuals, which supports the existence of a core virome. Lysogeny-associated genes were found in less than 10 % of the assembled genomes and a negative correlation was observed in the richness of bacterial and free-viral species, suggesting that the dominant lifestyle of gut phage is not lysogenic. This is in contrast to some of the earlier studies. Further, several hundred high-quality viral genomes were recovered. Detailed characterization of these genomes would be useful for understanding the biology of these viruses and their significance in human physiology.
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Affiliation(s)
- Kanchan Bhardwaj
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad-Gurugram Expressway, Faridabad-121 001, Haryana, India.,Manav Rachna International Institute of Research and Studies, Sector-43, Aravali hills, Faridabad-121 004, Haryana, India
| | - Anjali Garg
- Department of Biophysics, University of Delhi, South Campus, New Delhi-110021, India
| | - Abhay Deep Pandey
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad-Gurugram Expressway, Faridabad-121 001, Haryana, India
| | - Himani Sharma
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad-Gurugram Expressway, Faridabad-121 001, Haryana, India
| | - Manish Kumar
- Department of Biophysics, University of Delhi, South Campus, New Delhi-110021, India
| | - Sudhanshu Vrati
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad-Gurugram Expressway, Faridabad-121 001, Haryana, India
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Gulyaeva A, Garmaeva S, Ruigrok RAAA, Wang D, Riksen NP, Netea MG, Wijmenga C, Weersma RK, Fu J, Vila AV, Kurilshikov A, Zhernakova A. Discovery, diversity, and functional associations of crAss-like phages in human gut metagenomes from four Dutch cohorts. Cell Rep 2022; 38:110204. [PMID: 35021085 DOI: 10.1016/j.celrep.2021.110204] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/03/2021] [Accepted: 12/13/2021] [Indexed: 12/16/2022] Open
Abstract
The crAss-like phages are a diverse group of related viruses that includes some of the most abundant viruses of the human gut. To explore their diversity and functional role in human population and clinical cohorts, we analyze gut metagenomic data collected from 1,950 individuals from the Netherlands. We identify 1,556 crAss-like phage genomes, including 125 species-level and 32 genus-level clusters absent from the reference databases used. Analysis of their genomic features shows that closely related crAss-like phages can possess strikingly divergent regions responsible for transcription, presumably acquired through recombination. Prediction of crAss-like phage hosts points primarily to bacteria of the phylum Bacteroidetes, consistent with previous reports. Finally, we explore the temporal stability of crAss-like phages over a 4-year period and identify associations between the abundance of crAss-like phages and several human phenotypes, including depletion of crAss-like phages in inflammatory bowel disease patients.
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Affiliation(s)
- Anastasia Gulyaeva
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen 9713GZ, the Netherlands.
| | - Sanzhima Garmaeva
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen 9713GZ, the Netherlands
| | - Renate A A A Ruigrok
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen 9713GZ, the Netherlands; Department of Gastroenterology and Hepatology, University Medical Center Groningen, Groningen 9713GZ, the Netherlands
| | - Daoming Wang
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen 9713GZ, the Netherlands
| | - Niels P Riksen
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen 6525GA, the Netherlands
| | - Mihai G Netea
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen 6525GA, the Netherlands
| | - Cisca Wijmenga
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen 9713GZ, the Netherlands
| | - Rinse K Weersma
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen 9713GZ, the Netherlands; Department of Gastroenterology and Hepatology, University Medical Center Groningen, Groningen 9713GZ, the Netherlands
| | - Jingyuan Fu
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen 9713GZ, the Netherlands; Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen 9713GZ, the Netherlands
| | - Arnau Vich Vila
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen 9713GZ, the Netherlands; Department of Gastroenterology and Hepatology, University Medical Center Groningen, Groningen 9713GZ, the Netherlands
| | - Alexander Kurilshikov
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen 9713GZ, the Netherlands
| | - Alexandra Zhernakova
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen 9713GZ, the Netherlands.
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Shkoporov AN, Khokhlova EV, Stephens N, Hueston C, Seymour S, Hryckowian AJ, Scholz D, Ross RP, Hill C. Long-term persistence of crAss-like phage crAss001 is associated with phase variation in Bacteroides intestinalis. BMC Biol 2021; 19:163. [PMID: 34407825 PMCID: PMC8375218 DOI: 10.1186/s12915-021-01084-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [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: 02/19/2021] [Accepted: 07/01/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The crAss-like phages are ubiquitous and highly abundant members of the human gut virome that infect commensal bacteria of the order Bacteroidales. Although incapable of lysogeny, these viruses demonstrate long-term persistence in the human gut microbiome, dominating the virome in some individuals. RESULTS Here we show that rapid phase variation of alternate capsular polysaccharides in Bacteroides intestinalis cultures plays an important role in a dynamic equilibrium between phage sensitivity and resistance, allowing phage and bacteria to multiply in parallel. The data also suggests the role of a concomitant phage persistence mechanism associated with delayed lysis of infected cells, similar to carrier state infection. From an ecological and evolutionary standpoint, this type of phage-host interaction is consistent with the Piggyback-the-Winner model, which suggests a preference towards lysogenic or other "benign" forms of phage infection when the host is stably present at high abundance. CONCLUSION Long-term persistence of bacteriophage and host could result from mutually beneficial mechanisms driving bacterial strain-level diversity and phage survival in complex environments.
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Affiliation(s)
- Andrey N Shkoporov
- School of Microbiology, University College Cork, Cork, Ireland.
- APC Microbiome Ireland, University College Cork, Cork, Ireland.
| | | | - Niamh Stephens
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Cara Hueston
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Samuel Seymour
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Andrew J Hryckowian
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Medical Microbiology & Immunology, University of Wisconsin School of Medicine and Public Health, Madison, USA
| | - Dimitri Scholz
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - R Paul Ross
- School of Microbiology, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Colin Hill
- School of Microbiology, University College Cork, Cork, Ireland.
- APC Microbiome Ireland, University College Cork, Cork, Ireland.
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Guerin E, Shkoporov AN, Stockdale SR, Comas JC, Khokhlova EV, Clooney AG, Daly KM, Draper LA, Stephens N, Scholz D, Ross RP, Hill C. Isolation and characterisation of ΦcrAss002, a crAss-like phage from the human gut that infects Bacteroides xylanisolvens. Microbiome 2021; 9:89. [PMID: 33845877 PMCID: PMC8042965 DOI: 10.1186/s40168-021-01036-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 02/12/2021] [Indexed: 05/04/2023]
Abstract
BACKGROUND The gut phageome comprises a complex phage community of thousands of individual strains, with a few highly abundant bacteriophages. CrAss-like phages, which infect bacteria of the order Bacteroidales, are the most abundant bacteriophage family in the human gut and make an important contribution to an individual's core virome. Based on metagenomic data, crAss-like phages form a family, with four sub-families and ten candidate genera. To date, only three representatives isolated in pure culture have been reported: ΦcrAss001 and two closely related phages DAC15 and DAC17; all are members of the less abundant candidate genus VI. The persistence at high levels of both crAss-like phage and their Bacteroidales hosts in the human gut has not been explained mechanistically, and this phage-host relationship can only be properly studied with isolated phage-host pairs from as many genera as possible. RESULTS Faeces from a healthy donor with high levels of crAss-like phage was used to initiate a faecal fermentation in a chemostat, with selected antibiotics chosen to inhibit rapidly growing bacteria and selectively enrich for Gram-negative Bacteroidales. This had the objective of promoting the simultaneous expansion of crAss-like phages on their native hosts. The levels of seven different crAss-like phages expanded during the fermentation, indicating that their hosts were also present in the fermenter. The enriched supernatant was then tested against individual Bacteroidales strains isolated from the same faecal sample. This resulted in the isolation of a previously uncharacterised crAss-like phage of candidate genus IV of the proposed Alphacrassvirinae sub-family, ΦcrAss002, that infects the gut commensal Bacteroides xylanisolvens. ΦcrAss002 does not form plaques or spots on lawns of sensitive cells, nor does it lyse liquid cultures, even at high titres. In keeping with the co-abundance of phage and host in the human gut, ΦcrAss002 and Bacteroides xylanisolvens can also co-exist at high levels when co-cultured in laboratory media. CONCLUSIONS We report the isolation and characterisation of ΦcrAss002, the first representative of the proposed Alphacrassvirinae sub-family of crAss-like phages. ΦcrAss002 cannot form plaques or spots on bacterial lawns but can co-exist with its host, Bacteroides xylanisolvens, at very high levels in liquid culture without impacting on bacterial numbers. Video abstract.
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Affiliation(s)
- Emma Guerin
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- School of Microbiology, University College Cork, Cork, Ireland
| | | | | | | | | | - Adam G Clooney
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Karen M Daly
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | | | - Niamh Stephens
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Dimitri Scholz
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - R Paul Ross
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- School of Microbiology, University College Cork, Cork, Ireland
- Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, Ireland
| | - Colin Hill
- APC Microbiome Ireland, University College Cork, Cork, Ireland.
- School of Microbiology, University College Cork, Cork, Ireland.
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