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Xi Y, Li X, Liu L, Xiu F, Yi X, Chen H, You X. Sneaky tactics: Ingenious immune evasion mechanisms of Bartonella. Virulence 2024; 15:2322961. [PMID: 38443331 PMCID: PMC10936683 DOI: 10.1080/21505594.2024.2322961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 02/20/2024] [Indexed: 03/07/2024] Open
Abstract
Gram-negative Bartonella species are facultative intracellular bacteria that can survive in the harsh intracellular milieu of host cells. They have evolved strategies to evade detection and degradation by the host immune system, which ensures their proliferation in the host. Following infection, Bartonella alters the initial immunogenic surface-exposed proteins to evade immune recognition via antigen or phase variation. The diverse lipopolysaccharide structures of certain Bartonella species allow them to escape recognition by the host pattern recognition receptors. Additionally, the survival of mature erythrocytes and their resistance to lysosomal fusion further complicate the immune clearance of this species. Certain Bartonella species also evade immune attacks by producing biofilms and anti-inflammatory cytokines and decreasing endothelial cell apoptosis. Overall, these factors create a challenging landscape for the host immune system to rapidly and effectively eradicate the Bartonella species, thereby facilitating the persistence of Bartonella infections and creating a substantial obstacle for therapeutic interventions. This review focuses on the effects of three human-specific Bartonella species, particularly their mechanisms of host invasion and immune escape, to gain new perspectives in the development of effective diagnostic tools, prophylactic measures, and treatment options for Bartonella infections.
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Affiliation(s)
- Yixuan Xi
- Institute of Pathogenic Biology, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, University of South China, Hengyang, China
| | - Xinru Li
- Institute of Pathogenic Biology, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, University of South China, Hengyang, China
| | - Lu Liu
- Institute of Pathogenic Biology, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, University of South China, Hengyang, China
| | - Feichen Xiu
- Institute of Pathogenic Biology, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, University of South China, Hengyang, China
| | - Xinchao Yi
- Institute of Pathogenic Biology, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, University of South China, Hengyang, China
| | - Hongliang Chen
- Chenzhou NO.1 People’s Hospital, The Affiliated Chenzhou Hospital, Hengyang Medical College, University of South China, ChenZhou, China
| | - Xiaoxing You
- Institute of Pathogenic Biology, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, University of South China, Hengyang, China
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2
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Lee Y, Kwon S, Balaraju K, Jeon Y. Influence of phenotypic variation of Paenibacillus polymyxa E681 on growth promotion in cucumbers. Front Microbiol 2024; 15:1427265. [PMID: 39144205 PMCID: PMC11322358 DOI: 10.3389/fmicb.2024.1427265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Accepted: 07/10/2024] [Indexed: 08/16/2024] Open
Abstract
The goal of the current study is to better understand how bacteria may adapt to survive under adverse environmental conditions by altering and improving their phenotypes. In this study, we report the consequences of phenotypic variation in Paenibacillus polymyxa E681 (E681), a plant growth-promoting rhizobacterium (PGPR), isolated from winter barley root that has a variety of advantageous effects on crop plants. In our previous study, two different types of bacterial cells in E681 were distinguished. We used the term F-type for the variant that doesn't produce endospores and B-type for the endospore-producing wild type. Under the circumstances of our experiment, the cucumber rhizosphere soil and the surface of the seeds produced phenotypic variance. On tryptic soy agar (TSA) plates, the B-type spontaneously converted into the F-type, but the reverse was not reversible. Intriguingly, the plant growth promotion test displayed that cucumber seedlings treated with F-type cells had characteristics resembling those of the untreated control. Whereas, growth promotion of cucumber seedlings treated with B-type depends on temperature conditions. In particular, an increased growth promotion was observed at a low temperature of 20°C. The phenotypic change from B-type to F-type did not occur at 20°C for 6 days in the growth curve analysis of E681, but it did occur on the fourth and second days at 30 and 37°C, respectively. Therefore, before using PGPR strains as a bacterial inoculant for sustainable agriculture, it is imperative to resolve phenotypic variance in these strains.
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Affiliation(s)
- Younmi Lee
- Department of Plant Medicals, Andong National University, Andong, Republic of Korea
| | - Sungmoon Kwon
- Department of Plant Medicals, Andong National University, Andong, Republic of Korea
| | - Kotnala Balaraju
- Agricultural Science and Technology Research Institute, Andong National University, Andong, Republic of Korea
| | - Yongho Jeon
- Department of Plant Medicals, Andong National University, Andong, Republic of Korea
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3
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Garcia EM, Klimowicz AK, Edupuganti L, Topf MA, Bhide SR, Slusser DJ, Leib SM, Coddington CL, Matveyev A, Buck GA, Jefferson KK, Pepperell CS, Dillard JP. Phase variable colony variants are conserved across Gardnerella spp. and exhibit different virulence-associated phenotypes. mSphere 2024; 9:e0045024. [PMID: 38926904 PMCID: PMC11287997 DOI: 10.1128/msphere.00450-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 06/01/2024] [Indexed: 06/28/2024] Open
Abstract
The Gardnerella genus, comprising at least 13 species, is associated with the polymicrobial disorder bacterial vaginosis (BV). However, the details of BV pathogenesis are poorly defined, and the contributions made by individual species, including Gardnerella spp., are largely unknown. We report here that colony phenotypes characterized by size (large and small) and opacity (opaque and translucent) are phase variable and are conserved among all tested Gardnerella strains, representing at least 10 different species. With the hypothesis that these different variants could be an important missing piece to the enigma of how BV develops in vivo, we characterized their phenotypic, proteomic, and genomic differences. Beyond increased colony size, large colony variants showed reduced vaginolysin secretion and faster growth rate relative to small colony variants. The ability to inhibit the growth of Neisseria gonorrhoeae and commensal Lactobacillus species varied by strain and, in some instances, differed between variants. Proteomics analyses indicated that 127-173 proteins were differentially expressed between variants. Proteins with increased expression in large variants of both strains were associated with amino acid and protein synthesis and protein folding, whereas those increased in small variants were related to nucleotide synthesis, phosphate transport, ABC transport, and glycogen breakdown. Furthermore, whole genome sequencing analyses revealed an abundance of genes associated with variable homopolymer tracts, implicating slipped strand mispairing in Gardnerella phase variation and illuminating the potential for previously unrecognized heterogeneity within clonal populations. Collectively, these results suggest that phase variants may be primed to serve different roles in BV pathogenesis.IMPORTANCEBacterial vaginosis is the most common gynecological disorder in women of childbearing age. Gardnerella species are crucial to the development of this dysbiosis, but the mechanisms involved in the infection are not understood. We discovered that Gardnerella species vary between two different forms, reflected in bacterial colony size. A slow-growing form makes large amounts of the toxin vaginolysin and is better able to survive in human cervix tissue. A fast-growing form is likely the one that proliferates to high numbers just prior to symptom onset and forms the biofilm that serves as a scaffold for multiple BV-associated anaerobic bacteria. Identification of the proteins that vary between different forms of the bacteria as well as those that vary randomly provides insight into the factors important for Gardnerella infection and immune avoidance.
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Affiliation(s)
- Erin M. Garcia
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Amy K. Klimowicz
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Laahirie Edupuganti
- Center for Microbiome Engineering and Data Analysis, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Madeline A. Topf
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Shraddha R. Bhide
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Dawson J. Slusser
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Samantha M. Leib
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Cayden L. Coddington
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Andrey Matveyev
- Center for Microbiome Engineering and Data Analysis, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Gregory A. Buck
- Center for Microbiome Engineering and Data Analysis, Virginia Commonwealth University, Richmond, Virginia, USA
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Kimberly K. Jefferson
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Caitlin S. Pepperell
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medicine, Division of Infectious Diseases, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Joseph P. Dillard
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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4
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Passeri I, Vaccaro F, Mengoni A, Fagorzi C. Moving toward the Inclusion of Epigenomics in Bacterial Genome Evolution: Perspectives and Challenges. Int J Mol Sci 2024; 25:4425. [PMID: 38674013 PMCID: PMC11050019 DOI: 10.3390/ijms25084425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 04/05/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
The universality of DNA methylation as an epigenetic regulatory mechanism belongs to all biological kingdoms. However, while eukaryotic systems have been the primary focus of DNA methylation studies, the molecular mechanisms in prokaryotes are less known. Nevertheless, DNA methylation in prokaryotes plays a pivotal role in many cellular processes such as defense systems against exogenous DNA, cell cycle dynamics, and gene expression, including virulence. Thanks to single-molecule DNA sequencing technologies, genome-wide identification of methylated DNA is becoming feasible on a large scale, providing the possibility to investigate more deeply the presence, variability, and roles of DNA methylation. Here, we present an overview of the multifaceted roles of DNA methylation in prokaryotes and suggest research directions and tools which can enable us to better understand the contribution of DNA methylation to prokaryotic genome evolution and adaptation. In particular, we emphasize the need to understand the presence and role of transgenerational inheritance, as well as the impact of epigenomic signatures on adaptation and genome evolution. Research directions and the importance of novel computational tools are underlined.
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Affiliation(s)
| | | | - Alessio Mengoni
- Department of Biology, University of Florence, 50121 Firenze, Italy; (I.P.); (F.V.); (C.F.)
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Richard E, Darracq B, Littner E, Millot GA, Conte V, Cokelaer T, Engelstädter J, Rocha EPC, Mazel D, Loot C. Belt and braces: Two escape ways to maintain the cassette reservoir of large chromosomal integrons. PLoS Genet 2024; 20:e1011231. [PMID: 38578806 PMCID: PMC11023631 DOI: 10.1371/journal.pgen.1011231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 04/17/2024] [Accepted: 03/19/2024] [Indexed: 04/07/2024] Open
Abstract
Integrons are adaptive devices that capture, stockpile, shuffle and express gene cassettes thereby sampling combinatorial phenotypic diversity. Some integrons called sedentary chromosomal integrons (SCIs) can be massive structures containing hundreds of cassettes. Since most of these cassettes are non-expressed, it is not clear how they remain stable over long evolutionary timescales. Recently, it was found that the experimental inversion of the SCI of Vibrio cholerae led to a dramatic increase of the cassette excision rate associated with a fitness defect. Here, we question the evolutionary sustainability of this apparently counter selected genetic context. Through experimental evolution, we find that the integrase is rapidly inactivated and that the inverted SCI can recover its original orientation by homologous recombination between two insertion sequences (ISs) present in the array. These two outcomes of SCI inversion restore the normal growth and prevent the loss of cassettes, enabling SCIs to retain their roles as reservoirs of functions. These results illustrate a nice interplay between gene orientation, genome rearrangement, bacterial fitness and demonstrate how integrons can benefit from their embedded ISs.
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Affiliation(s)
- Egill Richard
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, Paris, France
- Sorbonne Université, ED515, Paris, France
| | - Baptiste Darracq
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, Paris, France
- Sorbonne Université, ED515, Paris, France
| | - Eloi Littner
- Sorbonne Université, ED515, Paris, France
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Microbial Evolutionary Genomics, Paris, France
- DGA CBRN Defence, Vert-le-Petit, France
| | - Gael A. Millot
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, Paris, France
| | - Valentin Conte
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, Paris, France
| | - Thomas Cokelaer
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, Paris, France
- Institut Pasteur, Université Paris Cité, Plateforme Technologique Biomics, Paris, France
| | - Jan Engelstädter
- School of the Environment, The University of Queensland, Brisbane, Australia
| | - Eduardo P. C. Rocha
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Microbial Evolutionary Genomics, Paris, France
| | - Didier Mazel
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, Paris, France
| | - Céline Loot
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, Paris, France
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6
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Dekker JP. Within-Host Evolution of Bacterial Pathogens in Acute and Chronic Infection. ANNUAL REVIEW OF PATHOLOGY 2024; 19:203-226. [PMID: 37832940 DOI: 10.1146/annurev-pathmechdis-051122-111408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2023]
Abstract
Bacterial pathogens undergo remarkable adaptive change in response to the selective forces they encounter during host colonization and infection. Studies performed over the past few decades have demonstrated that many general evolutionary processes can be discerned during the course of host adaptation, including genetic diversification of lineages, clonal succession events, convergent evolution, and balanced fitness trade-offs. In some cases, elevated mutation rates resulting from mismatch repair or proofreading deficiencies accelerate evolution, and active mobile genetic elements or phages may facilitate genome plasticity. The host immune response provides another critical component of the fitness landscapes guiding adaptation, and selection operating on pathogens at this level may lead to immune evasion and the establishment of chronic infection. This review summarizes recent advances in this field, with a special focus on different forms of bacterial genome plasticity in the context of infection, and considers clinical consequences of adaptive changes for the host.
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Affiliation(s)
- John P Dekker
- Bacterial Pathogenesis and Antimicrobial Resistance Unit, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA;
- National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
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7
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Long CM, Beare PA, Cockrell D, Binette P, Tesfamariam M, Richards C, Anderson M, McCormick-Ell J, Brose M, Anderson R, Omsland A, Pearson T, Heinzen RA. Natural reversion promotes LPS elongation in an attenuated Coxiella burnetii strain. Nat Commun 2024; 15:697. [PMID: 38267444 PMCID: PMC10808227 DOI: 10.1038/s41467-023-43972-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 11/24/2023] [Indexed: 01/26/2024] Open
Abstract
Lipopolysaccharide (LPS) phase variation is a critical aspect of virulence in many Gram-negative bacteria. It is of particular importance to Coxiella burnetii, the biothreat pathogen that causes Q fever, as in vitro propagation of this organism leads to LPS truncation, which is associated with an attenuated and exempted from select agent status (Nine Mile II, NMII). Here, we demonstrate that NMII was recovered from the spleens of infected guinea pigs. Moreover, these strains exhibit a previously unrecognized form of elongated LPS and display increased virulence in comparison with the initial NMII strain. The reversion of a 3-bp mutation in the gene cbu0533 directly leads to LPS elongation. To address potential safety concerns, we introduce a modified NMII strain unable to produce elongated LPS.
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Affiliation(s)
- Carrie M Long
- Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT, 59840, USA.
| | - Paul A Beare
- Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Diane Cockrell
- Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Picabo Binette
- Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Mahelat Tesfamariam
- Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Crystal Richards
- Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Matthew Anderson
- Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Jessica McCormick-Ell
- Office of the Director, Office of Research Services, Division of Occupational Health and Safety, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Megan Brose
- Office of the Director, Office of Research Services, Division of Occupational Health and Safety, National Institutes of Health, Hamilton, 59840, USA
| | - Rebecca Anderson
- Office of the Director, Office of Research Services, Division of Occupational Health and Safety, National Institutes of Health, Hamilton, 59840, USA
| | - Anders Omsland
- Paul G. Allen School for Global Health, College of Veterinary Medicine, Washington State University, Pullman, WA, 99164, USA
| | - Talima Pearson
- Department of Biological Sciences, Center for Microbial Genetics and Genomics, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Robert A Heinzen
- Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT, 59840, USA
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8
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Tram G, Jen FEC, Phillips ZN, Lancashire JF, Timms J, Poole J, Jennings MP, Atack JM. Phasevarions in Haemophilus influenzae biogroup aegyptius control expression of multiple proteins. Microbiol Spectr 2024; 12:e0260123. [PMID: 38054719 PMCID: PMC10783040 DOI: 10.1128/spectrum.02601-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/31/2023] [Indexed: 12/07/2023] Open
Abstract
IMPORTANCE Haemophilus influenzae biogroup aegyptius is a human-adapted pathogen and the causative agent of Brazilian purpuric fever (BPF), an invasive disease with high mortality, that sporadically manifests in children previously suffering conjunctivitis. Phase variation is a rapid and reversible switching of gene expression found in many bacterial species, and typically associated with outer-membrane proteins. Phase variation of cytoplasmic DNA methyltransferases has been shown to play important roles in bacterial gene regulation and can act as epigenetic switches, regulating the expression of multiple genes as part of systems called phasevarions (phase-variable regulons). This study characterized two alleles of the ModA phasevarion present in H. influenzae biogroup aegyptius, ModA13, found in non-BPF causing strains and ModA16, unique to BPF causing isolates. Phase variation of ModA13 and ModA16 led to genome-wide changes to DNA methylation resulting in altered protein expression. These changes did not affect serum resistance in H. influenzae biogroup aegyptius strains.
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Affiliation(s)
- Greg Tram
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Freda E.-C. Jen
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Zachary N. Phillips
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - John F. Lancashire
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Jamie Timms
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Jessica Poole
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Michael P. Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - John M. Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
- School of Environment and Science, Griffith University, Gold Coast, Queensland, Australia
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Mikucki A, Kahler CM. Microevolution and Its Impact on Hypervirulence, Antimicrobial Resistance, and Vaccine Escape in Neisseria meningitidis. Microorganisms 2023; 11:3005. [PMID: 38138149 PMCID: PMC10745880 DOI: 10.3390/microorganisms11123005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/07/2023] [Accepted: 12/14/2023] [Indexed: 12/24/2023] Open
Abstract
Neisseria meningitidis is commensal of the human pharynx and occasionally invades the host, causing the life-threatening illness invasive meningococcal disease. The meningococcus is a highly diverse and adaptable organism thanks to natural competence, a propensity for recombination, and a highly repetitive genome. These mechanisms together result in a high level of antigenic variation to invade diverse human hosts and evade their innate and adaptive immune responses. This review explores the ways in which this diversity contributes to the evolutionary history and population structure of the meningococcus, with a particular focus on microevolution. It examines studies on meningococcal microevolution in the context of within-host evolution and persistent carriage; microevolution in the context of meningococcal outbreaks and epidemics; and the potential of microevolution to contribute to antimicrobial resistance and vaccine escape. A persistent theme is the idea that the process of microevolution contributes to the development of new hyperinvasive meningococcal variants. As such, microevolution in this species has significant potential to drive future public health threats in the form of hypervirulent, antibiotic-resistant, vaccine-escape variants. The implications of this on current vaccination strategies are explored.
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Affiliation(s)
- August Mikucki
- Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Perth, WA 6009, Australia;
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Perth, WA 6009, Australia
| | - Charlene M. Kahler
- Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, University of Western Australia, Perth, WA 6009, Australia;
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Perth, WA 6009, Australia
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10
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Lei B, Hanks TS, Bao Y, Liu M. Slipped-strand mispairing within a polycytidine tract in transcriptional regulator mga leads to M protein phase variation and Mga length polymorphism in Group A Streptococcus. Front Microbiol 2023; 14:1212149. [PMID: 37434706 PMCID: PMC10330708 DOI: 10.3389/fmicb.2023.1212149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 06/06/2023] [Indexed: 07/13/2023] Open
Abstract
The M protein, a major virulence factor of Group A Streptococcus (GAS), is regulated by the multigene regulator Mga. An unexplained phenomena frequently occurring with in vitro genetic manipulation or culturing of M1T1 GAS strains is the loss of M protein production. This study was aimed at elucidating the basis for the loss of M protein production. The majority of M protein-negative (M-) variants had one C deletion at a tract of 8 cytidines starting at base 1,571 of the M1 mga gene, which is designated as c.1571C[8]. The C deletion led to a c.1571C[7] mga variant that has an open reading frame shift and encodes a Mga-M protein fusion protein. Transformation with a plasmid containing wild-type mga restored the production of the M protein in the c.1571C[7] mga variant. Isolates producing M protein (M+) were recovered following growth of the c.1571C[7] M protein-negative variant subcutaneously in mice. The majority of the recovered isolates with reestablished M protein production had reverted back from c.1571C[7] to c.1571C[8] tract and some M+ isolates lost another C in the c.1571C[7] tract, leading to a c.1571C[6] variant that encodes a functional Mga with 13 extra amino acid residues at the C-terminus compared with wild-type Mga. The nonfunctional c.1571C[7] and functional c.1571C[6] variants are present in M1, M12, M14, and M23 strains in NCBI genome databases, and a G-to-A nonsense mutation at base 1,657 of M12 c.1574C[7] mga leads to a functional c.1574C[7]/1657A mga variant and is common in clinical M12 isolates. The numbers of the C repeats in this polycytidine tract and the polymorphism at base 1,657 lead to polymorphism in the size of Mga among clinical isolates. These findings demonstrate the slipped-strand mispairing within the c.1574C[8] tract of mga as a reversible switch controlling M protein production phase variation in multiple GAS common M types.
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Affiliation(s)
- Benfang Lei
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
| | - Tracey S. Hanks
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
| | - Yunjuan Bao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, China
| | - Mengyao Liu
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
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11
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Bai J, Raustad N, Denoncourt J, van Opijnen T, Geisinger E. Genome-wide phage susceptibility analysis in Acinetobacter baumannii reveals capsule modulation strategies that determine phage infectivity. PLoS Pathog 2023; 19:e1010928. [PMID: 37289824 PMCID: PMC10249906 DOI: 10.1371/journal.ppat.1010928] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 04/27/2023] [Indexed: 06/10/2023] Open
Abstract
Phage have gained renewed interest as an adjunctive treatment for life-threatening infections with the resistant nosocomial pathogen Acinetobacter baumannii. Our understanding of how A. baumannii defends against phage remains limited, although this information could lead to improved antimicrobial therapies. To address this problem, we identified genome-wide determinants of phage susceptibility in A. baumannii using Tn-seq. These studies focused on the lytic phage Loki, which targets Acinetobacter by unknown mechanisms. We identified 41 candidate loci that increase susceptibility to Loki when disrupted, and 10 that decrease susceptibility. Combined with spontaneous resistance mapping, our results support the model that Loki uses the K3 capsule as an essential receptor, and that capsule modulation provides A. baumannii with strategies to control vulnerability to phage. A key center of this control is transcriptional regulation of capsule synthesis and phage virulence by the global regulator BfmRS. Mutations hyperactivating BfmRS simultaneously increase capsule levels, Loki adsorption, Loki replication, and host killing, while BfmRS-inactivating mutations have the opposite effect, reducing capsule and blocking Loki infection. We identified novel BfmRS-activating mutations, including knockouts of a T2 RNase protein and the disulfide formation enzyme DsbA, that hypersensitize bacteria to phage challenge. We further found that mutation of a glycosyltransferase known to alter capsule structure and bacterial virulence can also cause complete phage resistance. Finally, additional factors including lipooligosaccharide and Lon protease act independently of capsule modulation to interfere with Loki infection. This work demonstrates that regulatory and structural modulation of capsule, known to alter A. baumannii virulence, is also a major determinant of susceptibility to phage.
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Affiliation(s)
- Jinna Bai
- Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Nicole Raustad
- Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Jason Denoncourt
- Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Tim van Opijnen
- Broad Institute of MIT and Harvard, CISID, Cambridge, Massachusetts, United States of America
| | - Edward Geisinger
- Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
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12
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Bartlett J. Random with Respect to Fitness or External Selection? An Important but Often Overlooked Distinction. Acta Biotheor 2023; 71:12. [PMID: 36933070 DOI: 10.1007/s10441-023-09464-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 03/03/2023] [Indexed: 03/19/2023]
Abstract
Mutations are often described as being "random with respect to fitness." Here we show that the experiments used to establish randomness with respect to fitness are only capable of showing that mutations are random with respect to current external selection. Current debates about whether or not mutations are directed may be at least partially resolved by making use of this distinction. Additionally, this distinction has important mathematical, experimental, and inferential implications.
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13
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Hefetz I, Israeli O, Bilinsky G, Plaschkes I, Hazkani-Covo E, Hayouka Z, Lampert A, Helman Y. A reversible mutation in a genomic hotspot saves bacterial swarms from extinction. iScience 2023; 26:106043. [PMID: 36824284 PMCID: PMC9941203 DOI: 10.1016/j.isci.2023.106043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 10/10/2022] [Accepted: 01/20/2023] [Indexed: 01/26/2023] Open
Abstract
Microbial adaptation to changing environmental conditions is frequently mediated by hypermutable sequences. Here we demonstrate that such a hypermutable hotspot within a gene encoding a flagellar unit of Paenibacillus glucanolyticus generated spontaneous non-swarming mutants with increased stress resistance. These mutants, which survived conditions that eliminated wild-type cultures, could be carried by their swarming siblings when the colony spread, consequently increasing their numbers at the spreading edge. Of interest, the hypermutable nature of the aforementioned sequence enabled the non-swarming mutants to serve as "seeds" for a new generation of wild-type cells through reversion of the mutation. Using a mathematical model, we examined the survival dynamics of P. glucanolyticus colonies under fluctuating environments. Our experimental and theoretical results suggest that the non-swarming, stress-resistant mutants can save the colony from extinction. Notably, we identified this hypermutable sequence in flagellar genes of additional Paenibacillus species, suggesting that this phenomenon could be wide-spread and ecologically important.
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Affiliation(s)
- Idan Hefetz
- Department of Biotechnology, Institute for Biological Research, Ness-Ziona, Israel,Department of Plant Pathology and Microbiology, IES, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Ofir Israeli
- Department of Biochemistry and Molecular Biology, Institute for Biological Research, Ness-Ziona, Israel
| | - Gal Bilinsky
- Department of Biochemistry and Molecular Biology, Institute for Biological Research, Ness-Ziona, Israel
| | - Inbar Plaschkes
- Info-CORE, Bioinformatics Unit of the I-CORE at the Hebrew University of Jerusalem, Jerusalem, Israel
| | - Einat Hazkani-Covo
- Department of Natural and Life Sciences, The Open University of Israel, Ra’anana, Israel
| | - Zvi Hayouka
- Department of Biochemistry, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Adam Lampert
- Institute of Environmental Sciences (IES), Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel,Corresponding author
| | - Yael Helman
- Department of Plant Pathology and Microbiology, IES, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel,Corresponding author
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14
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Doijad SP, Gisch N, Frantz R, Kumbhar BV, Falgenhauer J, Imirzalioglu C, Falgenhauer L, Mischnik A, Rupp J, Behnke M, Buhl M, Eisenbeis S, Gastmeier P, Gölz H, Häcker GA, Käding N, Kern WV, Kola A, Kramme E, Peter S, Rohde AM, Seifert H, Tacconelli E, Vehreschild MJGT, Walker SV, Zweigner J, Schwudke D, Chakraborty T, Thoma N, Weber A, Vavra M, Schuster S, Peyerl-Hoffmann G, Hamprecht A, Proske S, Stelzer Y, Wille J, Lenke D, Bader B, Dinkelacker A, Hölzl F, Kunstle L, Chakraborty T. Resolving colistin resistance and heteroresistance in Enterobacter species. Nat Commun 2023; 14:140. [PMID: 36627272 PMCID: PMC9832134 DOI: 10.1038/s41467-022-35717-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 12/16/2022] [Indexed: 01/11/2023] Open
Abstract
Species within the Enterobacter cloacae complex (ECC) include globally important nosocomial pathogens. A three-year study of ECC in Germany identified Enterobacter xiangfangensis as the most common species (65.5%) detected, a result replicated by examining a global pool of 3246 isolates. Antibiotic resistance profiling revealed widespread resistance and heteroresistance to the antibiotic colistin and detected the mobile colistin resistance (mcr)-9 gene in 19.2% of all isolates. We show that resistance and heteroresistance properties depend on the chromosomal arnBCADTEF gene cassette whose products catalyze transfer of L-Ara4N to lipid A. Using comparative genomics, mutational analysis, and quantitative lipid A profiling we demonstrate that intrinsic lipid A modification levels are genospecies-dependent and governed by allelic variations in phoPQ and mgrB, that encode a two-component sensor-activator system and specific inhibitor peptide. By generating phoPQ chimeras and combining them with mgrB alleles, we show that interactions at the pH-sensing interface of the sensory histidine kinase phoQ dictate arnBCADTEF expression levels. To minimize therapeutic failures, we developed an assay that accurately detects colistin resistance levels for any ECC isolate.
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Affiliation(s)
- Swapnil Prakash Doijad
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Institute of Medical Microbiology, Justus Liebig University, Gießen, Germany
| | - Nicolas Gisch
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Renate Frantz
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Institute of Medical Microbiology, Justus Liebig University, Gießen, Germany
| | - Bajarang Vasant Kumbhar
- Department of Biological Sciences, Sunandan Divatia School of Science, NMIMS (Deemed-to-be) University, Vile Parle, Mumbai, India
| | - Jane Falgenhauer
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Institute of Medical Microbiology, Justus Liebig University, Gießen, Germany
| | - Can Imirzalioglu
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Institute of Medical Microbiology, Justus Liebig University, Gießen, Germany
| | - Linda Falgenhauer
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Institute of Medical Microbiology, Justus Liebig University, Gießen, Germany.,Institute of Hygiene and Environmental Medicine, Justus Liebig University, Gießen, Germany
| | - Alexander Mischnik
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany
| | - Jan Rupp
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany
| | - Michael Behnke
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität of Berlin and Berlin Institute of Health, Institute of Hygiene and Environmental Medicine, Berlin, Germany
| | - Michael Buhl
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Institute of Medical Microbiology and Hygiene, Tübingen University, Tübingen, Germany.,Division of Infectious Diseases, Department of Internal Medicine I, Tübingen University, Tübingen, Germany.,Institute of Clinical Hygiene, Medical Microbiology and Infectiology, Paracelsus Medical University, Klinikum Nürnberg, Nürnberg, Germany
| | - Simone Eisenbeis
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Division of Infectious Diseases, Department of Internal Medicine I, Tübingen University, Tübingen, Germany
| | - Petra Gastmeier
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität of Berlin and Berlin Institute of Health, Institute of Hygiene and Environmental Medicine, Berlin, Germany
| | - Hanna Gölz
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Institute for Medical Microbiology and Hygiene, Albert-Ludwigs-University, Freiburg, Germany
| | - Georg Alexander Häcker
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Institute for Medical Microbiology and Hygiene, Albert-Ludwigs-University, Freiburg, Germany
| | - Nadja Käding
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany
| | - Winfried V Kern
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Division of Infectious Diseases, Department of Medicine II, Faculty of Medicine and University Hospital and Medical Center, Albert-Ludwigs-University, Freiburg, Germany
| | - Axel Kola
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität of Berlin and Berlin Institute of Health, Institute of Hygiene and Environmental Medicine, Berlin, Germany
| | - Evelyn Kramme
- Department of Infectious Diseases and Microbiology, University of Lübeck, Lübeck, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität of Berlin and Berlin Institute of Health, Institute of Hygiene and Environmental Medicine, Berlin, Germany
| | - Silke Peter
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Institute of Medical Microbiology and Hygiene, Tübingen University, Tübingen, Germany
| | - Anna M Rohde
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität of Berlin and Berlin Institute of Health, Institute of Hygiene and Environmental Medicine, Berlin, Germany
| | - Harald Seifert
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Institute for Medical Microbiology, Immunology, and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Evelina Tacconelli
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Division of Infectious Diseases, Department of Internal Medicine I, Tübingen University, Tübingen, Germany
| | - Maria J G T Vehreschild
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Department I of Internal Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.,Department of Internal Medicine, Infectious Diseases, University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt, Germany
| | - Sarah V Walker
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Institute for Medical Microbiology, Immunology, and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Janine Zweigner
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Institute for Medical Microbiology, Immunology, and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Dominik Schwudke
- German Center for Infection Research (DZIF), Braunschweig, Germany.,Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany.,Airway Research Center North, Member of the German Center for Lung Research (DZL), Site: Research Center Borstel, Borstel, Germany
| | | | - Trinad Chakraborty
- German Center for Infection Research (DZIF), Braunschweig, Germany. .,Institute of Medical Microbiology, Justus Liebig University, Gießen, Germany.
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15
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Depta J, Niedźwiedzka-Rystwej P. The Phenomenon of Antibiotic Resistance in the Polar Regions: An Overview of the Global Problem. Infect Drug Resist 2023; 16:1979-1995. [PMID: 37034396 PMCID: PMC10081531 DOI: 10.2147/idr.s369023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 07/02/2022] [Indexed: 04/11/2023] Open
Abstract
The increasing prevalence of antibiotic resistance is a global problem in human and animal health. This leads to a reduction in the therapeutic effectiveness of the measures used so far and to the limitation of treatment options, which may pose a threat to human health and life. The problem of phenomenon of antibiotic resistance affects more and more the polar regions. This is due to the increase in tourist traffic and the number of people staying at research stations, unmodernised sewage systems in inhabited areas, as well as the migration of animals or the movement of microplastics, which may contain resistant bacteria. Research shows that the presence of antibiotic resistance genes is more dominant in zones of human and wildlife influence than in remote areas. In a polluted environment, there is evidence of a direct correlation between human activity and the spread and survival of antibiotic-resistant bacteria. Attention should be paid to the presence of resistance to synthetic and semi-synthetic antibiotics in the polar regions, which is likely to be correlated with human presence and activity, and possible steps to be taken. We need to understand many more aspects of this, such as bacterial epigenetics and environmental stress, in order to develop effective strategies for minimizing the spread of antibiotic resistance genes. Studying the diversity and abundance of antibiotic resistance genes in regions with less anthropogenic activity could provide insight into the diversity of primary genes and explain the historical evolution of antibiotic resistance.
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Affiliation(s)
- Julia Depta
- Institute of Biology, University of Szczecin, Szczecin, 71-412, Poland
| | - Paulina Niedźwiedzka-Rystwej
- Institute of Biology, University of Szczecin, Szczecin, 71-412, Poland
- Correspondence: Paulina Niedźwiedzka-Rystwej, Institute of Biology, University of Szczecin, Szczecin, 71-412, Poland, Tel +48 91 444 15 15, Email
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16
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Raad N, Tandon D, Hapfelmeier S, Polacek N. The stationary phase-specific sRNA FimR2 is a multifunctional regulator of bacterial motility, biofilm formation and virulence. Nucleic Acids Res 2022; 50:11858-11875. [PMID: 36354005 PMCID: PMC9723502 DOI: 10.1093/nar/gkac1025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 10/06/2022] [Accepted: 10/20/2022] [Indexed: 11/11/2022] Open
Abstract
Bacterial pathogens employ a plethora of virulence factors for host invasion, and their use is tightly regulated to maximize infection efficiency and manage resources in a nutrient-limited environment. Here we show that during Escherichia coli stationary phase the 3' UTR-derived small non-coding RNA FimR2 regulates fimbrial and flagellar biosynthesis at the post-transcriptional level, leading to biofilm formation as the dominant mode of survival under conditions of nutrient depletion. FimR2 interacts with the translational regulator CsrA, antagonizing its functions and firmly tightening control over motility and biofilm formation. Generated through RNase E cleavage, FimR2 regulates stationary phase biology by fine-tuning target mRNA levels independently of the chaperones Hfq and ProQ. The Salmonella enterica orthologue of FimR2 induces effector protein secretion by the type III secretion system and stimulates infection, thus linking the sRNA to virulence. This work reveals the importance of bacterial sRNAs in modulating various aspects of bacterial physiology including stationary phase and virulence.
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Affiliation(s)
- Nicole Raad
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Bern, Switzerland,Graduate School for Cellular and Biomedical Sciences, Bern, Switzerland
| | - Disha Tandon
- Graduate School for Cellular and Biomedical Sciences, Bern, Switzerland,Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | | | - Norbert Polacek
- To whom correspondence should be addressed. Tel: +41 31 684 43 20;
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17
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Pseudomonas aeruginosa Strains from Both Clinical and Environmental Origins Readily Adopt a Stable Small-Colony-Variant Phenotype Resulting from Single Mutations in c-di-GMP Pathways. J Bacteriol 2022; 204:e0018522. [PMID: 36102640 PMCID: PMC9578426 DOI: 10.1128/jb.00185-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A subpopulation of small-colony variants (SCVs) is a frequently observed feature of Pseudomonas aeruginosa isolates obtained from colonized cystic fibrosis lungs. Since most SCVs have until now been isolated from clinical samples, it remains unclear how widespread the ability of P. aeruginosa strains to develop this phenotype is and what the genetic mechanism(s) behind the emergence of SCVs are according to the origin of the isolate. In the present work, we investigated the ability of 22 P. aeruginosa isolates from various environmental origins to spontaneously adopt an SCV-like smaller alternative morphotype distinguishable from that of the ancestral parent strain under laboratory culture conditions. We found that all the P. aeruginosa strains tested could adopt an SCV phenotype, regardless of their origin. Whole-genome sequencing of SCVs obtained from clinical and environmental sources revealed single mutations exclusively in two distinct c-di-GMP signaling pathways, the Wsp and YfiBNR pathways. We conclude that the ability to switch to an SCV phenotype is a conserved feature of P. aeruginosa and results from the acquisition of a stable genetic mutation, regardless of the origin of the strain. IMPORTANCE P. aeruginosa is an opportunistic pathogen that thrives in many environments. It poses a significant health concern, notably because this bacterium is the most prevalent pathogen found in the lungs of people with cystic fibrosis. In infected hosts, its persistence is considered related to the emergence of an alternative small-colony-variant (SCV) phenotype. By reporting the distribution of P. aeruginosa SCVs in various nonclinical environments and the involvement of c-di-GMP in SCV emergence from both clinical and environmental strains, this work contributes to understanding a conserved adaptation mechanism used by P. aeruginosa to adapt readily in all environments. Hindering this adaptation strategy could help control persistent infection by P. aeruginosa.
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18
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Whiteway C, Valcek A, Philippe C, Strazisar M, De Pooter T, Mateus I, Breine A, Van der Henst C. Scarless excision of an insertion sequence restores capsule production and virulence in Acinetobacter baumannii. THE ISME JOURNAL 2022; 16:1473-1477. [PMID: 34949784 PMCID: PMC9038732 DOI: 10.1038/s41396-021-01179-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/07/2021] [Accepted: 12/16/2021] [Indexed: 11/12/2022]
Abstract
We identify a new mechanism mediating capsule production and virulence in the WHO and CDC priority ESKAPE pathogen Acinetobacter baumannii. Non-capsulated and avirulent bacteria can revert into a capsulated and virulent state upon scarless excision of an ISAba13 insertion sequence under stress conditions. Reversion events fully restore capsule production and in vivo virulence. This increases our knowledge about A. baumannii genome dynamics, and the regulation of capsule production, virulence and resistance.
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Affiliation(s)
- Clémence Whiteway
- Microbial Resistance and Drug Discovery, VIB-VUB Center for Structural Biology, VIB, Flanders Institute for Biotechnology, Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Adam Valcek
- Microbial Resistance and Drug Discovery, VIB-VUB Center for Structural Biology, VIB, Flanders Institute for Biotechnology, Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Chantal Philippe
- Research Unit in the Biology of Microorganisms (URBM), NARILIS, University of Namur (UNamur), Namur, Belgium
| | - Mojca Strazisar
- Neuromics Support Facility, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium.,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Tim De Pooter
- Neuromics Support Facility, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium.,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Ivan Mateus
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Anke Breine
- Microbial Resistance and Drug Discovery, VIB-VUB Center for Structural Biology, VIB, Flanders Institute for Biotechnology, Brussels, Belgium.,Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Charles Van der Henst
- Microbial Resistance and Drug Discovery, VIB-VUB Center for Structural Biology, VIB, Flanders Institute for Biotechnology, Brussels, Belgium. .,Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium.
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19
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Morawska LP, Hernandez-Valdes JA, Kuipers OP. Diversity of bet-hedging strategies in microbial communities-Recent cases and insights. WIREs Mech Dis 2022; 14:e1544. [PMID: 35266649 PMCID: PMC9286555 DOI: 10.1002/wsbm.1544] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 10/05/2021] [Accepted: 10/07/2021] [Indexed: 12/12/2022]
Abstract
Microbial communities are continuously exposed to unpredictable changes in their environment. To thrive in such dynamic habitats, microorganisms have developed the ability to readily switch phenotypes, resulting in a number of differently adapted subpopulations expressing various traits. In evolutionary biology, a particular case of phenotypic heterogeneity that evolved in an unpredictably changing environment has been defined as bet‐hedging. Bet‐hedging is a risk‐spreading strategy where isogenic populations stochastically (randomly) diversify their phenotypes, often resulting in maladapted individuals that suffer lower reproductive success. This fitness trade‐off in a specific environment may have a selective advantage upon the sudden environmental shift. Thus, a bet‐hedging strategy allows populations to persist in very dynamic habitats, but with a particular fitness cost. In recent years, numerous examples of phenotypic heterogeneity in different microorganisms have been observed, some suggesting bet‐hedging. Here, we highlight the latest reports concerning bet‐hedging phenomena in various microorganisms to show how versatile this strategy is within the microbial realms. This article is categorized under:Infectious Diseases > Molecular and Cellular Physiology
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Affiliation(s)
- Luiza P Morawska
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, Groningen, The Netherlands
| | - Jhonatan A Hernandez-Valdes
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, Groningen, The Netherlands
| | - Oscar P Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, Groningen, The Netherlands
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20
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Filipi K, Rahman WU, Osickova A, Osicka R. Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins. Microorganisms 2022; 10:microorganisms10030518. [PMID: 35336094 PMCID: PMC8953716 DOI: 10.3390/microorganisms10030518] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 12/04/2022] Open
Abstract
The Gram-negative bacterium Kingella kingae is part of the commensal oropharyngeal flora of young children. As detection methods have improved, K. kingae has been increasingly recognized as an emerging invasive pathogen that frequently causes skeletal system infections, bacteremia, and severe forms of infective endocarditis. K. kingae secretes an RtxA cytotoxin, which is involved in the development of clinical infection and belongs to an ever-growing family of cytolytic RTX (Repeats in ToXin) toxins secreted by Gram-negative pathogens. All RTX cytolysins share several characteristic structural features: (i) a hydrophobic pore-forming domain in the N-terminal part of the molecule; (ii) an acylated segment where the activation of the inactive protoxin to the toxin occurs by a co-expressed toxin-activating acyltransferase; (iii) a typical calcium-binding RTX domain in the C-terminal portion of the molecule with the characteristic glycine- and aspartate-rich nonapeptide repeats; and (iv) a C-proximal secretion signal recognized by the type I secretion system. RTX toxins, including RtxA from K. kingae, have been shown to act as highly efficient ‘contact weapons’ that penetrate and permeabilize host cell membranes and thus contribute to the pathogenesis of bacterial infections. RtxA was discovered relatively recently and the knowledge of its biological role remains limited. This review describes the structure and function of RtxA in the context of the most studied RTX toxins, the knowledge of which may contribute to a better understanding of the action of RtxA in the pathogenesis of K. kingae infections.
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21
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Yan W, Hall AB, Jiang X. Bacteroidales species in the human gut are a reservoir of antibiotic resistance genes regulated by invertible promoters. NPJ Biofilms Microbiomes 2022; 8:1. [PMID: 35013297 PMCID: PMC8748976 DOI: 10.1038/s41522-021-00260-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 11/26/2021] [Indexed: 12/21/2022] Open
Abstract
Antibiotic-resistance genes (ARGs) regulated by invertible promoters can mitigate the fitness cost of maintaining ARGs in the absence of antibiotics and could potentially prolong the persistence of ARGs in bacterial populations. However, the origin, prevalence, and distribution of these ARGs regulated by invertible promoters remains poorly understood. Here, we sought to assess the threat posed by ARGs regulated by invertible promoters by systematically searching for ARGs regulated by invertible promoters in the human gut microbiome and examining their origin, prevalence, and distribution. Through metagenomic assembly of 2227 human gut metagenomes and genomic analysis of the Unified Human Gastrointestinal Genome (UHGG) collection, we identified ARGs regulated by invertible promoters and categorized them into three classes based on the invertase-regulating phase variation. In the human gut microbiome, ARGs regulated by invertible promoters are exclusively found in Bacteroidales species. Through genomic analysis, we observed that ARGs regulated by invertible promoters have convergently originated from ARG insertions into glycan-synthesis loci that were regulated by invertible promoters at least three times. Moreover, all three classes of invertible promoters regulating ARGs are located within integrative conjugative elements (ICEs). Therefore, horizontal transfer via ICEs could explain the wide taxonomic distribution of ARGs regulated by invertible promoters. Overall, these findings reveal that glycan-synthesis loci regulated by invertible promoters in Bacteroidales species are an important hotspot for the emergence of clinically-relevant ARGs regulated by invertible promoters.
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Affiliation(s)
- Wei Yan
- National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - A Brantley Hall
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, Maryland, USA
| | - Xiaofang Jiang
- National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA.
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22
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Isenring J, Geirnaert A, Lacroix C, Stevens MJA. Bistable auto-aggregation phenotype in Lactiplantibacillus plantarum emerges after cultivation in in vitro colonic microbiota. BMC Microbiol 2021; 21:268. [PMID: 34610822 PMCID: PMC8493755 DOI: 10.1186/s12866-021-02331-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 09/24/2021] [Indexed: 11/28/2022] Open
Abstract
Background Auto-aggregation is a desired property for probiotic strains because it is suggested to promote colonization of the human intestine, to prevent pathogen infections and to modulate the colonic mucosa. We recently reported the generation of adapted mutants of Lactiplantibacillus plantarum NZ3400, a derivative of the model strain WCFS1, for colonization under adult colonic conditions of PolyFermS continuous intestinal fermentation models. Here we describe and characterize the emerge of an auto-aggregating phenotype in L. plantarum NZ3400 derivatives recovered from the modelled gut microbiota. Results L. plantarum isolates were recovered from reactor effluent of four different adult microbiota and from spontaneously formed reactor biofilms. Auto-aggregation was observed in L. plantarum recovered from all microbiota and at higher percentage when recovered from biofilm than from effluent. Further, auto-aggregation percentage increased over time of cultivation in the microbiota. Starvation of the gut microbiota by interrupting the inflow of nutritive medium enhanced auto-aggregation, suggesting a link to nutrient availability. Auto-aggregation was lost under standard cultivation conditions for lactobacilli in MRS medium. However, it was reestablished during growth on sucrose and maltose and in a medium that simulates the abiotic gut environment. Remarkably, none of these conditions resulted in an auto-aggregation phenotype in the wild type strain NZ3400 nor other non-aggregating L. plantarum, indicating that auto-aggregation depends on the strain history. Whole genome sequencing analysis did not reveal any mutation responsible for the auto-aggregation phenotype. Transcriptome analysis showed highly significant upregulation of LP_RS05225 (msa) at 4.1–4.4 log2-fold-change and LP_RS05230 (marR) at 4.5–5.4 log2-fold-change in all auto-aggregating strains compared to non-aggregating. These co-expressed genes encode a mannose-specific adhesin protein and transcriptional regulator, respectively. Mapping of the RNA-sequence reads to the promoter region of the msa-marR operon reveled a DNA inversion in this region that is predominant in auto-aggregating but not in non-aggregating strains. This strongly suggests a role of this inversion in the auto-aggregation phenotype. Conclusions L. plantarum NZ3400 adapts to the in vitro colonic environment by developing an auto-aggregation phenotype. Similar aggregation phenotypes may promote gut colonization and efficacy of other probiotics and should be further investigated by using validated continuous models of gut fermentation such as PolyFermS. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02331-x.
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Affiliation(s)
- Julia Isenring
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, 8092, Zürich, Switzerland
| | - Annelies Geirnaert
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, 8092, Zürich, Switzerland
| | - Christophe Lacroix
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, 8092, Zürich, Switzerland.
| | - Marc J A Stevens
- Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, 8092, Zürich, Switzerland.,Institute for Food Hygiene and Safety, University of Zürich, Zurich, Switzerland
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24
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Han P, Ma Y, Fu Z, Guo Z, Xie J, Wu Y, Yuan YJ. A DNA Inversion System in Eukaryotes Established via Laboratory Evolution. ACS Synth Biol 2021; 10:2222-2230. [PMID: 34420293 DOI: 10.1021/acssynbio.1c00132] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
DNA inversion is a type of site-specific recombination system that plays an important role in the generation of genetic diversity and phenotypic adaptation by programmed rearrangements in bacteria. However, no such inversion system exhibiting a strong directionality bias has been identified or developed in eukaryotes yet. Here, using directed evolution of Rci recombinase, a tyrosine recombinase from a bacterial DNA inversion system, we identified a mutant Rci8 with a ratio of inversion/deletion up to ∼4320 in yeast. Based on Rci8 recombinase and sfxa101 sites, we have established a DNA inversion system in yeast and mammalian cells, enabling specificity for DNA inversions between inverted sites over deletions between directly repeated sites. Our results validated that the reversible DNA inversion system can act as an on/off transcriptional switch. Moreover, we demonstrate that the inversion system can also work on linear chromosomes. The eukaryotic DNA inversion system would provide a new tool for fields of genetic circuits, cellular barcoding, and synthetic genomes.
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Affiliation(s)
- Peiyan Han
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Yuan Ma
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Zongheng Fu
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Zhou Guo
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Jiangnan Xie
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Yi Wu
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Ying-jin Yuan
- Frontier Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300072, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
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25
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Kabwe M, Dashper S, Bachrach G, Tucci J. Bacteriophage manipulation of the microbiome associated with tumour microenvironments-can this improve cancer therapeutic response? FEMS Microbiol Rev 2021; 45:6188389. [PMID: 33765142 DOI: 10.1093/femsre/fuab017] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 03/21/2021] [Indexed: 12/11/2022] Open
Abstract
Some cancer treatment failures have been attributed to the tumour microbiota, with implications that microbiota manipulation may improve treatment efficacy. While antibiotics have been used to control bacterial growth, their dysbiotic effects on the microbiome, failure to penetrate biofilms and decreased efficacy due to increasing antimicrobial resistance by bacteria, suggest alternatives are needed. Bacteriophages may provide a precise means for targeting oncobacteria whose relative abundance is increased in tumour tissue microbiomes. Fusobacterium, Streptococcus, Peptostreptococcus, Prevotella, Parvimonas, and Treponema species are prevalent in tumour tissue microbiomes of some cancers. They may promote cancer growth by dampening immunity, stimulating release of proinflammatory cytokines, and directly interacting with cancer cells to stimulate proliferation. Lytic bacteriophages against some of these oncobacteria have been isolated and characterised. The search continues for others. The possibility exists for their testing as adjuncts to complement existing therapies. In this review, we highlight the role of oncobacteria, specifically those whose relative abundance in the intra-tumour microbiome is increased, and discuss the potential for bacteriophages against these micro-organisms to augment existing cancer therapies. The capacity for bacteriophages to modulate immunity and kill specific bacteria makes them suitable candidates to manipulate the tumour microbiome and negate the effects of these oncobacteria.
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Affiliation(s)
- Mwila Kabwe
- Department of Pharmacy and Biomedical Sciences, La Trobe Institute for Molecular Science, La Trobe University, Sharon St. Bendigo, Victoria 3550, Australia
| | - Stuart Dashper
- Melbourne Dental School, University of Melbourne, 720 Swanston St, Parkville, Victoria 3010, Australia
| | - Gilad Bachrach
- The Institute of Dental Sciences, The Hebrew University-Hadassah School of Dental Medicine, PO Box 12272, Jerusalem 9112102, Israel
| | - Joseph Tucci
- Department of Pharmacy and Biomedical Sciences, La Trobe Institute for Molecular Science, La Trobe University, Sharon St. Bendigo, Victoria 3550, Australia
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26
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Dose fractionation as a promising strategy to improve UV disinfection. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2021. [DOI: 10.1016/j.jpap.2021.100034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Yamamoto S, Iyoda S, Ohnishi M. Stabilizing Genetically Unstable Simple Sequence Repeats in the Campylobacter jejuni Genome by Multiplex Genome Editing: a Reliable Approach for Delineating Multiple Phase-Variable Genes. mBio 2021; 12:e0140121. [PMID: 34425708 PMCID: PMC8437040 DOI: 10.1128/mbio.01401-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 07/21/2021] [Indexed: 11/20/2022] Open
Abstract
Hypermutable simple sequence repeats (SSRs) are major drivers of phase variation in Campylobacter jejuni. The presence of multiple SSR-mediated phase-variable genes encoding enzymes that modify surface structures, including capsular polysaccharide (CPS) and lipooligosaccharide (LOS), generates extreme cell surface diversity within bacterial populations, thereby promoting adaptation to selective pressures in host environments. Therefore, genetically controlling SSR-mediated phase variation can be important for achieving stable and reproducible research on C. jejuni. Here, we show that natural "cotransformation" is an effective method for C. jejuni genome editing. Cotransformation is a trait of naturally competent bacteria that causes uptake/integration of multiple different DNA molecules, which has been recently adapted to multiplex genome editing by natural transformation (MuGENT), a method for introducing multiple mutations into the genomes of these bacteria. We found that cotransformation efficiently occurred in C. jejuni. To examine the feasibility of MuGENT in C. jejuni, we "locked" different polyG SSR tracts in strain NCTC11168 (which are located in the biosynthetic CPS/LOS gene clusters) into either the ON or OFF configurations. This approach, termed "MuGENT-SSR," enabled the generation of all eight edits within 2 weeks and the identification of a phase-locked strain with a highly stable type of Penner serotyping, a CPS-based serotyping scheme. Furthermore, extensive genome editing of this strain by MuGENT-SSR identified a phase-variable gene that determines the Penner serotype of NCTC11168. Thus, MuGENT-SSR provides a platform for genetic and phenotypic engineering of genetically unstable C. jejuni, making it a reliable approach for elucidating the mechanisms underlying phase-variable expression of specific phenotypes. IMPORTANCE Campylobacter jejuni is the leading bacterial cause of foodborne gastroenteritis in developed countries and occasionally progresses to the autoimmune disease Guillain-Barré syndrome. A relatively large number of hypermutable simple sequence repeat (SSR) tracts in the C. jejuni genome markedly decreases its phenotypic stability through reversible changes in the ON or OFF expression states of the genes in which they reside, a phenomenon called phase variation. Thus, controlling SSR-mediated phase variation can be important for achieving stable and reproducible research on C. jejuni. In this study, we developed a feasible and effective approach for genetically manipulate multiple SSR tracts in the C. jejuni genome using natural cotransformation, a trait of naturally transformable bacterial species that causes the uptake and integration of multiple different DNA molecules. This approach will greatly help to improve the genetic and phenotypic stability of C. jejuni to enable diverse applications in research and development.
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Affiliation(s)
- Shouji Yamamoto
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Sunao Iyoda
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Makoto Ohnishi
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
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28
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A comparative metabologenomic approach reveals mechanistic insights into Streptomyces antibiotic crypticity. Proc Natl Acad Sci U S A 2021; 118:2103515118. [PMID: 34326261 PMCID: PMC8346890 DOI: 10.1073/pnas.2103515118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Streptomyces genomes harbor numerous, biosynthetic gene clusters (BGCs) encoding for drug-like compounds. While some of these BGCs readily yield expected products, many do not. Biosynthetic crypticity represents a significant hurdle to drug discovery, and the biological mechanisms that underpin it remain poorly understood. Polycyclic tetramate macrolactam (PTM) antibiotic production is widespread within the Streptomyces genus, and examples of active and cryptic PTM BGCs are known. To reveal further insights into the causes of biosynthetic crypticity, we employed a PTM-targeted comparative metabologenomics approach to analyze a panel of S. griseus clade strains that included both poor and robust PTM producers. By comparing the genomes and PTM production profiles of these strains, we systematically mapped the PTM promoter architecture within the group, revealed that these promoters are directly activated via the global regulator AdpA, and discovered that small promoter insertion-deletion lesions (indels) differentiate weaker PTM producers from stronger ones. We also revealed an unexpected link between robust PTM expression and griseorhodin pigment coproduction, with weaker S. griseus-clade PTM producers being unable to produce the latter compound. This study highlights promoter indels and biosynthetic interactions as important, genetically encoded factors that impact BGC outputs, providing mechanistic insights that will undoubtedly extend to other Streptomyces BGCs. We highlight comparative metabologenomics as a powerful approach to expose genomic features that differentiate strong, antibiotic producers from weaker ones. This should prove useful for rational discovery efforts and is orthogonal to current engineering and molecular signaling approaches now standard in the field.
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29
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Bonkowski M, Tarkka M, Razavi BS, Schmidt H, Blagodatskaya E, Koller R, Yu P, Knief C, Hochholdinger F, Vetterlein D. Spatiotemporal Dynamics of Maize ( Zea mays L.) Root Growth and Its Potential Consequences for the Assembly of the Rhizosphere Microbiota. Front Microbiol 2021; 12:619499. [PMID: 33815308 PMCID: PMC8010349 DOI: 10.3389/fmicb.2021.619499] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 02/16/2021] [Indexed: 12/20/2022] Open
Abstract
Numerous studies have shown that plants selectively recruit microbes from the soil to establish a complex, yet stable and quite predictable microbial community on their roots – their “microbiome.” Microbiome assembly is considered as a key process in the self-organization of root systems. A fundamental question for understanding plant-microbe relationships is where a predictable microbiome is formed along the root axis and through which microbial dynamics the stable formation of a microbiome is challenged. Using maize as a model species for which numerous data on dynamic root traits are available, this mini-review aims to give an integrative overview on the dynamic nature of root growth and its consequences for microbiome assembly based on theoretical considerations from microbial community ecology.
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Affiliation(s)
- Michael Bonkowski
- Terrestrial Ecology, Institute of Zoology, University of Cologne, Cologne, Germany
| | - Mika Tarkka
- Department of Soil Ecology, Helmholtz Centre for Environmental Research - UFZ, Halle, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Bahar S Razavi
- Department of Soil and Plant Microbiome, Christian-Albrecht University of Kiel, Kiel, Germany
| | - Hannes Schmidt
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Evgenia Blagodatskaya
- Department of Soil Ecology, Helmholtz Centre for Environmental Research - UFZ, Halle, Germany
| | - Robert Koller
- Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Peng Yu
- Emmy Noether Group Root Functional Biology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, Germany
| | - Claudia Knief
- Institute of Crop Science and Resource Conservation - Molecular Biology of the Rhizosphere, University of Bonn, Bonn, Germany
| | - Frank Hochholdinger
- Crop Functional Genomics, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Bonn, Germany
| | - Doris Vetterlein
- Department of Soil System Science, Helmholtz Centre for Environmental Research - UFZ, Halle, Germany.,Soil Science, Martin-Luther-University Halle-Wittenberg, Halle, Germany
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30
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Ageorges V, Monteiro R, Leroy S, Burgess CM, Pizza M, Chaucheyras-Durand F, Desvaux M. Molecular determinants of surface colonisation in diarrhoeagenic Escherichia coli (DEC): from bacterial adhesion to biofilm formation. FEMS Microbiol Rev 2021; 44:314-350. [PMID: 32239203 DOI: 10.1093/femsre/fuaa008] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/31/2020] [Indexed: 12/11/2022] Open
Abstract
Escherichia coli is primarily known as a commensal colonising the gastrointestinal tract of infants very early in life but some strains being responsible for diarrhoea, which can be especially severe in young children. Intestinal pathogenic E. coli include six pathotypes of diarrhoeagenic E. coli (DEC), namely, the (i) enterotoxigenic E. coli, (ii) enteroaggregative E. coli, (iii) enteropathogenic E. coli, (iv) enterohemorragic E. coli, (v) enteroinvasive E. coli and (vi) diffusely adherent E. coli. Prior to human infection, DEC can be found in natural environments, animal reservoirs, food processing environments and contaminated food matrices. From an ecophysiological point of view, DEC thus deal with very different biotopes and biocoenoses all along the food chain. In this context, this review focuses on the wide range of surface molecular determinants acting as surface colonisation factors (SCFs) in DEC. In the first instance, SCFs can be broadly discriminated into (i) extracellular polysaccharides, (ii) extracellular DNA and (iii) surface proteins. Surface proteins constitute the most diverse group of SCFs broadly discriminated into (i) monomeric SCFs, such as autotransporter (AT) adhesins, inverted ATs, heat-resistant agglutinins or some moonlighting proteins, (ii) oligomeric SCFs, namely, the trimeric ATs and (iii) supramolecular SCFs, including flagella and numerous pili, e.g. the injectisome, type 4 pili, curli chaperone-usher pili or conjugative pili. This review also details the gene regulatory network of these numerous SCFs at the various stages as it occurs from pre-transcriptional to post-translocational levels, which remains to be fully elucidated in many cases.
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Affiliation(s)
- Valentin Ageorges
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Ricardo Monteiro
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France.,GSK, Via Fiorentina 1, 53100 Siena, Italy
| | - Sabine Leroy
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
| | - Catherine M Burgess
- Food Safety Department, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland
| | | | - Frédérique Chaucheyras-Durand
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France.,Lallemand Animal Nutrition SAS, F-31702 Blagnac Cedex, France
| | - Mickaël Desvaux
- Université Clermont Auvergne, INRAE, MEDiS, F-63000 Clermont-Ferrand, France
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31
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Gor V, Ohniwa RL, Morikawa K. No Change, No Life? What We Know about Phase Variation in Staphylococcus aureus. Microorganisms 2021; 9:microorganisms9020244. [PMID: 33503998 PMCID: PMC7911514 DOI: 10.3390/microorganisms9020244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 12/13/2022] Open
Abstract
Phase variation (PV) is a well-known phenomenon of high-frequency reversible gene-expression switching. PV arises from genetic and epigenetic mechanisms and confers a range of benefits to bacteria, constituting both an innate immune strategy to infection from bacteriophages as well as an adaptation strategy within an infected host. PV has been well-characterized in numerous bacterial species; however, there is limited direct evidence of PV in the human opportunistic pathogen Staphylococcus aureus. This review provides an overview of the mechanisms that generate PV and focuses on earlier and recent findings of PV in S. aureus, with a brief look at the future of the field.
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Affiliation(s)
- Vishal Gor
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
- Correspondence: (V.G.); (K.M.)
| | - Ryosuke L. Ohniwa
- Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan;
| | - Kazuya Morikawa
- Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan;
- Correspondence: (V.G.); (K.M.)
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32
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Huang X, Wang J, Li J, Liu Y, Liu X, Li Z, Kurniyati K, Deng Y, Wang G, Ralph JD, De Ste Croix M, Escobar-Gonzalez S, Roberts RJ, Veening JW, Lan X, Oggioni MR, Li C, Zhang JR. Prevalence of phase variable epigenetic invertons among host-associated bacteria. Nucleic Acids Res 2020; 48:11468-11485. [PMID: 33119758 PMCID: PMC7672463 DOI: 10.1093/nar/gkaa907] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 09/28/2020] [Accepted: 10/23/2020] [Indexed: 12/14/2022] Open
Abstract
Type I restriction-modification (R-M) systems consist of a DNA endonuclease (HsdR, HsdM and HsdS subunits) and methyltransferase (HsdM and HsdS subunits). The hsdS sequences flanked by inverted repeats (referred to as epigenetic invertons) in certain Type I R-M systems undergo invertase-catalyzed inversions. Previous studies in Streptococcus pneumoniae have shown that hsdS inversions within clonal populations produce subpopulations with profound differences in the methylome, cellular physiology and virulence. In this study, we bioinformatically identified six major clades of the tyrosine and serine family invertases homologs from 16 bacterial phyla, which potentially catalyze hsdS inversions in the epigenetic invertons. In particular, the epigenetic invertons are highly enriched in host-associated bacteria. We further verified hsdS inversions in the Type I R-M systems of four representative host-associated bacteria and found that each of the resultant hsdS allelic variants specifies methylation of a unique DNA sequence. In addition, transcriptome analysis revealed that hsdS allelic variations in Enterococcus faecalis exert significant impact on gene expression. These findings indicate that epigenetic switches driven by invertases in the epigenetic invertons broadly operate in the host-associated bacteria, which may broadly contribute to bacterial host adaptation and virulence beyond the role of the Type I R-M systems against phage infection.
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Affiliation(s)
- Xueting Huang
- Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Juanjuan Wang
- Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Jing Li
- Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Yanni Liu
- Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Xue Liu
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, CH 1015, Switzerland
| | - Zeyao Li
- Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Kurni Kurniyati
- Department of Oral and Craniofacial Molecular Biology, School of Dentistry, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Yijie Deng
- Department of Oral and Craniofacial Molecular Biology, School of Dentistry, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Guilin Wang
- W. M. Keck Foundation Biotechnology Resource Laboratory, Yale University, New Haven, CT 06520, USA
| | - Joseph D Ralph
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK
| | - Megan De Ste Croix
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK
| | - Sara Escobar-Gonzalez
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK
| | | | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, CH 1015, Switzerland
| | - Xun Lan
- Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Marco R Oggioni
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK
| | - Chunhao Li
- Department of Oral and Craniofacial Molecular Biology, School of Dentistry, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Jing-Ren Zhang
- Department of Basic Medical Science, School of Medicine, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
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Reva ON, Korotetskiy IS, Joubert M, Shilov SV, Jumagaziyeva AB, Suldina NA, Ilin AI. The Effect of Iodine-Containing Nano-Micelles, FS-1, on Antibiotic Resistance, Gene Expression and Epigenetic Modifications in the Genome of Multidrug Resistant MRSA Strain Staphylococcus aureus ATCC BAA-39. Front Microbiol 2020; 11:581660. [PMID: 33193215 PMCID: PMC7642360 DOI: 10.3389/fmicb.2020.581660] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/18/2020] [Indexed: 12/14/2022] Open
Abstract
Application of supplementary drugs which increase susceptibility of pathogenic bacteria to antibiotics is a promising yet unexplored approach to overcome the global problem of multidrug-resistant infections. The discovery of a new drug, an iodine-containing nano-molecular complex FS-1, which has proven to improve susceptibility to antibiotics in various pathogens, including MRSA strain Staphylococcus aureus ATCC BAA-39TM, allowed studying this phenomenon. Chromosomal DNA and total RNA samples extracted from the FS-1 treated strain (FS) and from the negative control (NC) cultures were sequenced by PacBio SMRT and Ion Torrent technologies, respectively. PacBio DNA reads were used to assemble chromosomal DNA of the NC and FS variants of S. aureus BAA-39 and to perform profiling of epigenetically modified nucleotides. Results of transcriptional profiling, variant calling and detection of epigenetic modifications in the FS variant were compared to the NC variant. Additionally, the genetic alterations caused by the treatment of S. aureus BAA-39 with FS-1 were compared to the results of a similar experiment conducted with another model organism, E. coli ATCC BAA-196. Several commonalities in responses of these phylogenetically distant microorganisms to the treatment with FS-1 were discovered, which included metabolic transition toward anaerobiosis and oxidative/osmotic stress response. S. aureus culture appeared to be more sensitive to FS-1 due to a higher penetrability of cells by iodine bound compounds, which caused carbonyl stress associated with nucleotide damaging by FS-1, abnormal epigenetic modifications and an increased rate of mutations. It was hypothesized that the disrupted pattern of adenine methylated loci within methicillin-resistance chromosome cassettes (SCCmec) may promote excision of this antibiotic resistance determinant from chromosomes while the altered pattern of cytosine methylation was behind the adaptive gene regulation in the culture FS. The selection against the antibiotic resistance in bacterial populations caused by abnormal epigenetic modifications exemplifies possible mechanisms of antibiotic resistance reversion induced by iodine-containing compounds. These finding will facilitate development of therapeutic agents against multidrug-resistant infections.
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Affiliation(s)
- Oleg N. Reva
- Centre for Bioinformatics and Computational Biology (CBCB), Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | | | - Monique Joubert
- Centre for Bioinformatics and Computational Biology (CBCB), Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Sergey V. Shilov
- Scientific Center for Anti-Infectious Drugs (SCAID), Almaty, Kazakhstan
| | | | | | - Alexandr I. Ilin
- Scientific Center for Anti-Infectious Drugs (SCAID), Almaty, Kazakhstan
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Nye TM, Fernandez NL, Simmons LA. A positive perspective on DNA methylation: regulatory functions of DNA methylation outside of host defense in Gram-positive bacteria. Crit Rev Biochem Mol Biol 2020; 55:576-591. [PMID: 33059472 DOI: 10.1080/10409238.2020.1828257] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The presence of post-replicative DNA methylation is pervasive among both prokaryotic and eukaryotic organisms. In bacteria, the study of DNA methylation has largely been in the context of restriction-modification systems, where DNA methylation serves to safeguard the chromosome against restriction endonuclease cleavage intended for invading DNA. There has been a growing recognition that the methyltransferase component of restriction-modification systems can also regulate gene expression, with important contributions to virulence factor gene expression in bacterial pathogens. Outside of restriction-modification systems, DNA methylation from orphan methyltransferases, which lack cognate restriction endonucleases, has been shown to regulate important processes, including DNA replication, DNA mismatch repair, and the regulation of gene expression. The majority of research and review articles have been focused on DNA methylation in the context of Gram-negative bacteria, with emphasis toward Escherichia coli, Caulobacter crescentus, and related Proteobacteria. Here we summarize the epigenetic functions of DNA methylation outside of host defense in Gram-positive bacteria, with a focus on the regulatory effects of both phase variable methyltransferases and DNA methyltransferases from traditional restriction-modification systems.
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Affiliation(s)
- Taylor M Nye
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Nicolas L Fernandez
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Lyle A Simmons
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
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Eisenbart SK, Alzheimer M, Pernitzsch SR, Dietrich S, Stahl S, Sharma CM. A Repeat-Associated Small RNA Controls the Major Virulence Factors of Helicobacter pylori. Mol Cell 2020; 80:210-226.e7. [PMID: 33002424 DOI: 10.1016/j.molcel.2020.09.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 07/29/2020] [Accepted: 09/04/2020] [Indexed: 12/12/2022]
Abstract
Many bacterial pathogens regulate their virulence genes via phase variation, whereby length-variable simple sequence repeats control the transcription or coding potential of those genes. Here, we have exploited this relationship between DNA structure and physiological function to discover a globally acting small RNA (sRNA) regulator of virulence in the gastric pathogen Helicobacter pylori. Our study reports the first sRNA whose expression is affected by a variable thymine (T) stretch in its promoter. We show the sRNA post-transcriptionally represses multiple major pathogenicity factors of H. pylori, including CagA and VacA, by base pairing to their mRNAs. We further demonstrate transcription of the sRNA is regulated by the nickel-responsive transcriptional regulator NikR (thus named NikS for nickel-regulated sRNA), thereby linking virulence factor regulation to nickel concentrations. Using in-vitro infection experiments, we demonstrate NikS affects host cell internalization and epithelial barrier disruption. Together, our results show NikS is a phase-variable, post-transcriptional global regulator of virulence properties in H. pylori.
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Affiliation(s)
- Sara K Eisenbart
- Chair of Molecular Infection Biology II, Institute of Molecular Infection Biology (IMIB), University of Würzburg, 97080 Würzburg, Germany
| | - Mona Alzheimer
- Chair of Molecular Infection Biology II, Institute of Molecular Infection Biology (IMIB), University of Würzburg, 97080 Würzburg, Germany
| | - Sandy R Pernitzsch
- Chair of Molecular Infection Biology II, Institute of Molecular Infection Biology (IMIB), University of Würzburg, 97080 Würzburg, Germany
| | - Sascha Dietrich
- Core Unit Systems Medicine, Interdisciplinary Center for Clinical Research (IZKF) of the University Hospital Würzburg, 97080 Würzburg, Germany
| | - Stephanie Stahl
- Chair of Molecular Infection Biology II, Institute of Molecular Infection Biology (IMIB), University of Würzburg, 97080 Würzburg, Germany
| | - Cynthia M Sharma
- Chair of Molecular Infection Biology II, Institute of Molecular Infection Biology (IMIB), University of Würzburg, 97080 Würzburg, Germany.
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Antimicrobial Resistance in Escherichia coli and Resistance Genes in Coliphages from a Small Animal Clinic and in a Patient Dog with Chronic Urinary Tract Infection. Antibiotics (Basel) 2020; 9:antibiotics9100652. [PMID: 33003333 PMCID: PMC7600197 DOI: 10.3390/antibiotics9100652] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 02/07/2023] Open
Abstract
Antimicrobial resistance is on the rise in certain pathogens that infect pets and their owners. This has raised concerns about the use of antibiotics and the transfer of resistance elements in small animal clinics. We sampled a surgery unit, diagnostic rooms after disinfection, and a dog with chronic urinary tract infection (UTI), in a small animal clinic in Austria, and isolated/characterized phages and Escherichia (E.) coli for antimicrobial resistance, resistance genes and transduction ability. Neither the coliphages nor E. coli were isolated in the 20 samples of the surgery units and diagnostic rooms. From the urinary tract of the dog, we recovered 57 E. coli isolates and 60 coliphages. All of the E. coli isolates were determined as resistant against nalidixic acid, 47 against ampicillin, 34 against sulfonamides, and 33 against streptomycin. No isolate held resistance against tetracycline, trimethoprim, kanamycin, or chloramphenicol. Among the 60 phages, 29 tested positive for one or more resistance gene(s) by PCR, but none was able to transduce it to a laboratory strain or to an E. coli isolated from samples. Nevertheless, six phages out of 60 were able to transduce ampicillin resistance (bla gene) after being grown on a puc19 harboring E. coli strain.
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Kandel PP, Baltrus DA, Hockett KL. Pseudomonas Can Survive Tailocin Killing via Persistence-Like and Heterogenous Resistance Mechanisms. J Bacteriol 2020; 202:e00142-20. [PMID: 32312747 PMCID: PMC7283598 DOI: 10.1128/jb.00142-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 04/16/2020] [Indexed: 12/14/2022] Open
Abstract
Phage tail-like bacteriocins (tailocins) are bacterially produced protein toxins that mediate competitive interactions between cocolonizing bacteria. Both theoretical and experimental research has shown there are intransitive interactions between bacteriocin-producing, bacteriocin-sensitive, and bacteriocin-resistant populations, whereby producers outcompete sensitive cells, sensitive cells outcompete resistant cells, and resistant cells outcompete producers. These so-called rock-paper-scissors dynamics explain how all three populations occupy the same environment, without one driving the others extinct. Using Pseudomonas syringae as a model, we demonstrate that otherwise sensitive cells survive bacteriocin exposure through a physiological mechanism. This mechanism allows cells to survive bacteriocin killing without acquiring resistance. We show that a significant fraction of the target cells that survive a lethal dose of tailocin did not exhibit any detectable increase in survival during a subsequent exposure. Tailocin persister cells were more prevalent in stationary- rather than log-phase cultures. Of the fraction of cells that gained detectable resistance, there was a range from complete (insensitive) to incomplete (partially sensitive) resistance. By using genomic sequencing and genetic engineering, we showed that a mutation in a hypothetical gene containing 8 to 10 transmembrane domains causes tailocin high persistence and that genes of various glycosyltransferases cause incomplete and complete tailocin resistance. Importantly, of the several classes of mutations, only those causing complete tailocin resistance compromised host fitness. This result indicates that bacteria likely utilize persistence to survive bacteriocin-mediated killing without suffering the costs associated with resistance. This research provides important insight into how bacteria can escape the trap of fitness trade-offs associated with gaining de novo tailocin resistance.IMPORTANCE Bacteriocins are bacterially produced protein toxins that are proposed as antibiotic alternatives. However, a deeper understanding of the responses of target bacteria to bacteriocin exposure is lacking. Here, we show that target cells of Pseudomonas syringae survive lethal bacteriocin exposure through both physiological persistence and genetic resistance mechanisms. Cells that are not growing rapidly rely primarily on persistence, whereas those growing rapidly are more likely to survive via resistance. We identified various mutations in lipopolysaccharide biogenesis-related regions involved in tailocin persistence and resistance. By assessing host fitness of various classes of mutants, we showed that persistence and subtle resistance are mechanisms P. syringae uses to survive competition and preserve host fitness. These results have important implications for developing bacteriocins as alternative therapeutic agents.
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Affiliation(s)
- Prem P Kandel
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - David A Baltrus
- School of Plant Sciences, University of Arizona, Tucson, Arizona, USA
| | - Kevin L Hockett
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, Pennsylvania, USA
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
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Wanford JJ, Holmes JC, Bayliss CD, Green LR. Meningococcal core and accessory phasomes vary by clonal complex. Microb Genom 2020; 6:e000367. [PMID: 32375989 PMCID: PMC7371114 DOI: 10.1099/mgen.0.000367] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 03/27/2020] [Indexed: 11/21/2022] Open
Abstract
Neisseria meningitidis is a Gram-negative human commensal pathogen, with extensive phenotypic plasticity afforded by phase-variable (PV) gene expression. Phase variation is a stochastic switch in gene expression from an ON to an OFF state, mediated by localized hypermutation of simple sequence repeats (SSRs). Circulating N. meningitidis clones vary in propensity to cause disease, with some clonal complexes (ccs) classified as hypervirulent and others as carriage-associated. We examined the PV gene repertoires, or phasome, of these lineages in order to determine whether phase variation contributes to disease propensity. We analysed 3328 genomes representative of nine circulating meningococcal ccs with PhasomeIt, a tool that identifies PV genes by the presence of SSRs and homologous gene clusters. The presence, absence and functions of all identified PV gene clusters were confirmed by annotation or blast searches within the Neisseria PubMLST database. While no significant differences were detected in the number of PV genes or the core, conserved phasome content between hypervirulent and carriage lineages, individual ccs exhibited major variations in PV gene numbers. Phylogenetic clusters produced by phasome or core genome analyses were similar, indicating co-evolution of PV genes with the core genome. While conservation of PV clusters is high, with 76 % present in all meningococcal isolates, maintenance of an SSR is variable, ranging from conserved in all isolates to present only in a single cc, indicating differing evolutionary trajectories for each lineage. Diverse functional groups of PV genes were present across the meningococcal lineages; however, the majority directly or indirectly influence bacterial surface antigens and could impact on future vaccine development. Finally, we observe that meningococci have open pan phasomes, indicating ongoing evolution of PV gene content and a significant potential for adaptive changes in this clinically relevant genus.
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Affiliation(s)
- Joseph J. Wanford
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Jonathan C. Holmes
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | | | - Luke R. Green
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
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Yi X, Kazlauskas R, Travisano M. Evolutionary innovation using EDGE, a system for localized elevated mutagenesis. PLoS One 2020; 15:e0232330. [PMID: 32353078 PMCID: PMC7192385 DOI: 10.1371/journal.pone.0232330] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 04/14/2020] [Indexed: 11/19/2022] Open
Abstract
Mutations arising across the whole genome can hinder the emergence of evolutionary innovation required for adaptation because many mutations are deleterious. This trade-off is overcome by elevated mutagenesis to localized loci. Examples include phase variation and diversity-generating retroelements. However, these mechanisms are rare in nature; and all have narrow mutational spectra limiting evolutionary innovation. Here, we engineer a platform of Experimental Designed Genic Evolution (EDGE) to study the potential for evolutionary novelty at a single locus. Experimental evolution with EDGE shows that bacterial resistance to a novel antibiotic readily evolves, provided that elevated mutagenesis is focused on a relevant gene. A model is proposed to account for the cost and benefit of such single loci to adaptation in a changing environment and explains their high mutation rates, limited innovation, and the rarity of localized mutagenesis in nature. Overall, our results suggest that localized mutation systems can facilitate continuing adaptive evolution without necessarily restricting the spectrum of mutations. EDGE has utility in dissecting the complex process of adaptation with its localized, efficient evolution.
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Affiliation(s)
- Xiao Yi
- BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Romas Kazlauskas
- BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, United States of America
- Biochemistry, Molecular Biology and Biophysics, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Michael Travisano
- BioTechnology Institute, University of Minnesota, St. Paul, Minnesota, United States of America
- Ecology, Evolution and Behavior, University of Minnesota, St. Paul, Minnesota, United States of America
- * E-mail:
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40
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Eraso JM, Kachroo P, Olsen RJ, Beres SB, Zhu L, Badu T, Shannon S, Cantu CC, Saavedra MO, Kubiak SL, Porter AR, DeLeo FR, Musser JM. Genetic heterogeneity of the Spy1336/R28-Spy1337 virulence axis in Streptococcus pyogenes and effect on gene transcript levels and pathogenesis. PLoS One 2020; 15:e0229064. [PMID: 32214338 PMCID: PMC7098570 DOI: 10.1371/journal.pone.0229064] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/28/2020] [Indexed: 12/20/2022] Open
Abstract
Streptococcus pyogenes is a strict human pathogen responsible for more than 700 million infections annually worldwide. Strains of serotype M28 S. pyogenes are typically among the five more abundant types causing invasive infections and pharyngitis in adults and children. Type M28 strains also have an unusual propensity to cause puerperal sepsis and neonatal disease. We recently discovered that a one-nucleotide indel in an intergenic homopolymeric tract located between genes Spy1336/R28 and Spy1337 altered virulence in a mouse model of infection. In the present study, we analyzed size variation in this homopolymeric tract and determined the extent of heterogeneity in the number of tandemly-repeated 79-amino acid domains in the coding region of Spy1336/R28 in large samples of strains recovered from humans with invasive infections. Both repeat sequence elements are highly polymorphic in natural populations of M28 strains. Variation in the homopolymeric tract results in (i) changes in transcript levels of Spy1336/R28 and Spy1337 in vitro, (ii) differences in virulence in a mouse model of necrotizing myositis, and (iii) global transcriptome changes as shown by RNAseq analysis of isogenic mutant strains. Variation in the number of tandem repeats in the coding sequence of Spy1336/R28 is responsible for size variation of R28 protein in natural populations. Isogenic mutant strains in which genes encoding R28 or transcriptional regulator Spy1337 are inactivated are significantly less virulent in a nonhuman primate model of necrotizing myositis. Our findings provide impetus for additional studies addressing the role of R28 and Spy1337 variation in pathogen-host interactions.
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Affiliation(s)
- Jesus M. Eraso
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Priyanka Kachroo
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Randall J. Olsen
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
- Departments of Pathology and Laboratory Medicine and Microbiology and Immunology, Weill Cornell Medical College, New York, New York, United States of America
| | - Stephen B. Beres
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Luchang Zhu
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Traci Badu
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Sydney Shannon
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Concepcion C. Cantu
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Matthew Ojeda Saavedra
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Samantha L. Kubiak
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
| | - Adeline R. Porter
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Frank R. DeLeo
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - James M. Musser
- Center for Molecular and Translational Human Infectious Diseases Research, Department of Pathology and Genomic Medicine, Houston Methodist Research Institute and Houston Methodist Hospital, Houston, Texas, United States of America
- Departments of Pathology and Laboratory Medicine and Microbiology and Immunology, Weill Cornell Medical College, New York, New York, United States of America
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Antibiotic Resistance and Epigenetics: More to It than Meets the Eye. Antimicrob Agents Chemother 2020; 64:AAC.02225-19. [PMID: 31740560 DOI: 10.1128/aac.02225-19] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The discovery of antibiotics in the last century is considered one of the most important achievements in the history of medicine. Antibiotic usage has significantly reduced morbidity and mortality associated with bacterial infections. However, inappropriate use of antibiotics has led to emergence of antibiotic resistance at an alarming rate. Antibiotic resistance is regarded as a major health care challenge of this century. Despite extensive research, well-documented biochemical mechanisms and genetic changes fail to fully explain mechanisms underlying antibiotic resistance. Several recent reports suggest a key role for epigenetics in the development of antibiotic resistance in bacteria. The intrinsic heterogeneity as well as transient nature of epigenetic inheritance provides a plausible backdrop for high-paced emergence of drug resistance in bacteria. The methylation of adenines and cytosines can influence mutation rates in bacterial genomes, thus modulating antibiotic susceptibility. In this review, we discuss a plethora of recently discovered epigenetic mechanisms and their emerging roles in antibiotic resistance. We also highlight specific epigenetic mechanisms that merit further investigation for their role in antibiotic resistance.
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Abstract
Nontypeable Haemophilus influenzae (NTHi) is a leading cause of respiratory tract infections worldwide and continues to be a global health burden. Adhesion and colonization of host cells are crucial steps in bacterial pathogenesis, and in many strains of NTHi, the interaction with the host is mediated by the high molecular weight adhesins HMW1A and HMW2A. These adhesins are N-glycoproteins that are modified by cytoplasmic glycosyltransferases HMW1C and HMW2C. Phase variation in the number of short sequence repeats in the promoters of hmw1A and hmw2A directly affects their expression. Here, we report the presence of similar variable repeat elements in the promoters of hmw1C and hmw2C in diverse NTHi isolates. In an ex vivo assay, we systematically altered the substrate and glycosyltransferase expression and showed that both of these factors quantitatively affected the site-specific efficiency of glycosylation on HMW-A. This represents a novel mechanism through which phase variation can generate diversity in the quantitative extent of site-specific post-translational modifications on antigenic surface proteins. Glycosylation occupancy was incomplete at many sites, variable between sites, and generally lower close to the C-terminus of HMW-A. We investigated the causes of this variability. As HMW-C glycosylates HMW-A in the cytoplasm, we tested how secretion affected glycosylation on HMW-A and showed that retaining HMW-A in the cytoplasm indeed increased glycosylation occupancy across the full length of the protein. Site-directed mutagenesis showed that HMW-C had no inherent preference for glycosylating asparagines in NxS or NxT sequons. This work provides key insights into factors contributing to the heterogenous modifications of NTHi HMW-A adhesins, expands knowledge of NTHi population diversity and pathogenic capability, and is relevant to vaccine design for NTHi and related pathogens.
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Reva ON, Swanevelder DZH, Mwita LA, Mwakilili AD, Muzondiwa D, Joubert M, Chan WY, Lutz S, Ahrens CH, Avdeeva LV, Kharkhota MA, Tibuhwa D, Lyantagaye S, Vater J, Borriss R, Meijer J. Genetic, Epigenetic and Phenotypic Diversity of Four Bacillus velezensis Strains Used for Plant Protection or as Probiotics. Front Microbiol 2019; 10:2610. [PMID: 31803155 PMCID: PMC6873887 DOI: 10.3389/fmicb.2019.02610] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/28/2019] [Indexed: 12/11/2022] Open
Abstract
Bacillus velezensis strains are applied as ecologically safe biopesticides, plant growth promoting rhizobacteria (PGPR), and in veterinary probiotics. They are abundant in various environments including soil, plants, marine habitats, the intestinal micro-flora, etc. The mechanisms underlying this adaptive plasticity and bioactivity are not well understood, nor is it clear why several strains outperform other same species isolates by their bioactivities. The main objective of this work was to demonstrate versatility of bioactivities and lifestyle strategies of the selected B. velezensis strains suitable to serve as model organisms in future studies. Here, we performed a comparative study of newly sequenced genomes of four B. velezensis isolates with distinct phenotypes and isolation origin, which were assessed by RNA sequencing under the effect of root exudate stimuli and profiled by epigenetic modifications of chromosomal DNA. Among the selected strains, UCMB5044 is an oligotrophic PGPR strain adapted to nutrient poor desert soils. UCMB5113 and At1 are endophytes that colonize plants and require nutrient rich media. In contrast, the probiotic strain, UCMB5007, is a copiotroph, which shows no propensity to colonize plants. PacBio and Illumina sequencing approaches were used to generate complete genome assemblies, tracing epigenetic modifications, and determine gene expression profiles. All sequence data was deposited at NCBI. The strains, UCMB5113 and At1, show 99% sequence identity and similar phenotypes despite being isolated from geographically distant regions. UCMB5007 and UCMB5044 represent another group of organisms with almost identical genomes but dissimilar phenotypes and plant colonization propensity. The two plant associated strains, UCMB5044 and UCMB5113, share 398 genes putatively associated with root colonization, which are activated by exposure to maize root exudates. In contrast, UCMB5007 did not respond to root exudate stimuli. It was hypothesized that alterations in the global methylation pattern and some other epigenetic modifications enable adaptation of strains to different habitats and therefore may be of importance in terms of the biotechnological applicability of these bacteria. Contrary, the ability to grow on root exudates as a sole source of nutrients or a strong antagonism against phytopathogens showed by the strains in vitro cannot be considered as good predictors of PGPR activities.
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Affiliation(s)
- Oleg N Reva
- Centre for Bioinformatics and Computational Biology, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | | | - Liberata A Mwita
- Centre for Bioinformatics and Computational Biology, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa.,Department of Pharmaceutical Microbiology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Aneth David Mwakilili
- Department of Molecular Biology and Biotechnology, University of Dar es Salaam, Dar es Salaam, Tanzania.,Department of Plant Protection, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Dillon Muzondiwa
- Centre for Bioinformatics and Computational Biology, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Monique Joubert
- Centre for Bioinformatics and Computational Biology, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Wai Yin Chan
- Biotechnology Platform, Agricultural Research Council, Pretoria, South Africa.,Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa.,Forestry and Agricultural Biotechnology Institute, DST-NRF Centre of Excellence in Tree Health Biotechnology, University of Pretoria, Pretoria, South Africa
| | - Stefanie Lutz
- Agroscope, Molecular Diagnostics, Genomics and Bioinformatics and SIB Swiss Institute of Bioinformatics, Wädenswil, Switzerland
| | - Christian H Ahrens
- Agroscope, Molecular Diagnostics, Genomics and Bioinformatics and SIB Swiss Institute of Bioinformatics, Wädenswil, Switzerland
| | - Lylia V Avdeeva
- Department of Antibiotics, D.K. Zabolotny Institute of Microbiology and Virology, Kyiv, Ukraine
| | - Maksim A Kharkhota
- Department of Antibiotics, D.K. Zabolotny Institute of Microbiology and Virology, Kyiv, Ukraine
| | - Donatha Tibuhwa
- Department of Molecular Biology and Biotechnology, University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Sylvester Lyantagaye
- Department of Molecular Biology and Biotechnology, University of Dar es Salaam, Dar es Salaam, Tanzania
| | | | - Rainer Borriss
- Institut für Biologie, Humboldt Universität zu Berlin, Berlin, Germany
| | - Johan Meijer
- Department of Plant Biology, Linnéan Center for Plant Biology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Sigalova OM, Chaplin AV, Bochkareva OO, Shelyakin PV, Filaretov VA, Akkuratov EE, Burskaia V, Gelfand MS. Chlamydia pan-genomic analysis reveals balance between host adaptation and selective pressure to genome reduction. BMC Genomics 2019; 20:710. [PMID: 31510914 PMCID: PMC6740158 DOI: 10.1186/s12864-019-6059-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 08/22/2019] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Chlamydia are ancient intracellular pathogens with reduced, though strikingly conserved genome. Despite their parasitic lifestyle and isolated intracellular environment, these bacteria managed to avoid accumulation of deleterious mutations leading to subsequent genome degradation characteristic for many parasitic bacteria. RESULTS We report pan-genomic analysis of sixteen species from genus Chlamydia including identification and functional annotation of orthologous genes, and characterization of gene gains, losses, and rearrangements. We demonstrate the overall genome stability of these bacteria as indicated by a large fraction of common genes with conserved genomic locations. On the other hand, extreme evolvability is confined to several paralogous gene families such as polymorphic membrane proteins and phospholipase D, and likely is caused by the pressure from the host immune system. CONCLUSIONS This combination of a large, conserved core genome and a small, evolvable periphery likely reflect the balance between the selective pressure towards genome reduction and the need to adapt to escape from the host immunity.
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Affiliation(s)
- Olga M. Sigalova
- Kharkevich Institute for Information Transmission Problems, RAS, Moscow, Russia
- current address: European Molecular Biology Laboratory, Heidelberg, Germany
| | - Andrei V. Chaplin
- Microbiology and Virology Department, Pirogov Russian National Research Medical University, Moscow, Russia
| | - Olga O. Bochkareva
- Kharkevich Institute for Information Transmission Problems, RAS, Moscow, Russia
- current address: Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Pavel V. Shelyakin
- Kharkevich Institute for Information Transmission Problems, RAS, Moscow, Russia
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Vavilov Institute of General Genetics, RAS, Moscow, Russia
| | | | - Evgeny E. Akkuratov
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg, Russia
- current address: Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, Stockholm, Sweden
| | - Valentina Burskaia
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Mikhail S. Gelfand
- Kharkevich Institute for Information Transmission Problems, RAS, Moscow, Russia
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Faculty of Computer Science, Higher School of Economics, Moscow, Russia
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45
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Mori H, Evans-Yamamoto D, Ishiguro S, Tomita M, Yachie N. Fast and global detection of periodic sequence repeats in large genomic resources. Nucleic Acids Res 2019; 47:e8. [PMID: 30304510 PMCID: PMC6344855 DOI: 10.1093/nar/gky890] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 09/20/2018] [Indexed: 12/12/2022] Open
Abstract
Periodically repeating DNA and protein elements are involved in various important biological events including genomic evolution, gene regulation, protein complex formation, and immunity. Notably, the currently used genome editing tools such as ZFNs, TALENs, and CRISPRs are also all associated with periodically repeating biomolecules of natural organisms. Despite the biological importance of periodically repeating sequences and the expectation that new genome editing modules could be discovered from such periodical repeats, no software that globally detects such structured elements in large genomic resources in a high-throughput and unsupervised manner has been developed. We developed new software, SPADE (Search for Patterned DNA Elements), that exhaustively explores periodic DNA and protein repeats from large-scale genomic datasets based on k-mer periodicity evaluation. With a simple constraint, sequence periodicity, SPADE captured reported genome-editing-associated sequences and other protein families involving repeating domains such as tetratricopeptide, ankyrin and WD40 repeats with better performance than the other software designed for limited sets of repetitive biomolecular sequences, suggesting the high potential of this software to contribute to the discovery of new biological events and new genome editing modules.
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Affiliation(s)
- Hideto Mori
- Synthetic Biology Division, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo 153-8904, Japan.,Institute for Advanced Biosciences, Keio University, Tsuruoka 997-0035, Japan.,Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa 252-0882, Japan
| | - Daniel Evans-Yamamoto
- Synthetic Biology Division, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo 153-8904, Japan.,Institute for Advanced Biosciences, Keio University, Tsuruoka 997-0035, Japan.,Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa 252-0882, Japan
| | - Soh Ishiguro
- Synthetic Biology Division, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo 153-8904, Japan.,Institute for Advanced Biosciences, Keio University, Tsuruoka 997-0035, Japan.,Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa 252-0882, Japan
| | - Masaru Tomita
- Institute for Advanced Biosciences, Keio University, Tsuruoka 997-0035, Japan.,Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa 252-0882, Japan.,Department of Environment and Information Studies, Keio University, Fujisawa 252-0882, Japan
| | - Nozomu Yachie
- Synthetic Biology Division, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo 153-8904, Japan.,Institute for Advanced Biosciences, Keio University, Tsuruoka 997-0035, Japan.,Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa 252-0882, Japan.,Department of Biological Sciences, School of Science, The University of Tokyo, Tokyo 113-0033, Japan.,PRESTO, Japan Science and Technology Agency (JST), Tokyo 153-8904, Japan
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46
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Abstract
Staphylococcus aureus is responsible for a broad range of infections. This pathogen has a vast arsenal of virulence factors at its disposal, but avirulent strains are frequently isolated as the cause of clinical infections. These isolates have a mutated agr locus and have been believed to have no evolutionary future. Here we show that a fraction of Agr-negative strains can repair their mutated agr locus with mechanisms resembling phase variation. The agr revertants sustain an Agr OFF state as long as they exist as a minority but can activate their Agr system upon phagocytosis. These revertant cells might function as a cryptic insurance strategy to survive immune-mediated host stress that arises during infection. Staphylococcus aureus is an important human pathogen whose success is largely attributed to its vast arsenal of virulence factors that facilitate its invasion into, and survival within, the human host. The expression of these virulence factors is controlled by the quorum sensing accessory gene regulator (Agr) system. However, a large proportion of clinical S. aureus isolates are consistently found to have a mutationally inactivated Agr system. These mutants have a survival advantage in the host but are considered irreversible mutants. Here we show, for the first time, that a fraction of Agr-negative mutants can revert their Agr activity. By serially passaging Agr-negative strains and screening for phenotypic reversion of hemolysis and subsequent sequencing, we identified two mutational events responsible for reversion: a genetic duplication plus inversion event and a poly(A) tract alteration. Additionally, we demonstrate that one clinical Agr-negative methicillin-resistant S. aureus (MRSA) isolate could reproducibly generate Agr-revertant colonies with a poly(A) tract genetic mechanism. We also show that these revertants activate their Agr system upon phagocytosis. We propose a model in which a minor fraction of Agr-negative S. aureus strains are phase variants that can revert their Agr activity and may act as a cryptic insurance strategy against host-mediated stress.
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47
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Effects of phenotypic variations on the microbial hydroxylation of fatty acids by Pseudomonas sp. NRRL B-2994. J Biosci Bioeng 2019; 129:41-46. [PMID: 31375401 DOI: 10.1016/j.jbiosc.2019.06.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 06/01/2019] [Accepted: 06/15/2019] [Indexed: 11/23/2022]
Abstract
Hydroxy fatty acids (HFAs) are highly valued industrial materials. Pseudomonas sp. NRRL B-2994 was used for stereospecific microbial biotransformation to hydroxylate unsaturated fatty acids (UFAs). As Pseudomonas sp. was continuously subcultured, the hydroxylation capability (both conversion rate and productivity) decreased. A morphology change was observed from large to small colonies. To produce stereospecific 10-hydroxy-12(Z)-octadecenoic acid from plant oils by using Pseudomonas sp. NRRL B-2994, the effect of phenotypic variations related to microbial hydroxylation of UFAs was confirmed. The conversion rate and the total productivity of creating HFAs from UFAs by microbial hydroxylation were highly dependent upon colony phenotype variations of Pseudomonas sp. NRRL B-2994. The morphological change was responsible for a lower rate of hydroxylation. The small colony variants showed increased hydrophobicity of the cell surface resulting in cell aggregation in liquid culture and lower hydroxylation due to limited exposure of substrates, UFAs. Small colony variants could be reverted to typical large colony variants. An economically feasible process was established for microbial hydroxylation using large colony variants with 50% HFA conversion rate and 10-15 g/L of productivity.
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Jiang X, Hall AB, Arthur TD, Plichta DR, Covington CT, Poyet M, Crothers J, Moses PL, Tolonen AC, Vlamakis H, Alm EJ, Xavier RJ. Invertible promoters mediate bacterial phase variation, antibiotic resistance, and host adaptation in the gut. Science 2019; 363:181-187. [PMID: 30630933 DOI: 10.1126/science.aau5238] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 12/03/2018] [Indexed: 12/20/2022]
Abstract
Phase variation, the reversible alternation between genetic states, enables infection by pathogens and colonization by commensals. However, the diversity of phase variation remains underexplored. We developed the PhaseFinder algorithm to quantify DNA inversion-mediated phase variation. A systematic search of 54,875 bacterial genomes identified 4686 intergenic invertible DNA regions (invertons), revealing an enrichment in host-associated bacteria. Invertons containing promoters often regulate extracellular products, underscoring the importance of surface diversity for gut colonization. We found invertons containing promoters regulating antibiotic resistance genes that shift to the ON orientation after antibiotic treatment in human metagenomic data and in vitro, thereby mitigating the cost of antibiotic resistance. We observed that the orientations of some invertons diverge after fecal microbiota transplant, potentially as a result of individual-specific selective forces.
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Affiliation(s)
- Xiaofang Jiang
- Center for Microbiome Informatics and Therapeutics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - A Brantley Hall
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.,Center for Computational and Integrative Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | | | - Damian R Plichta
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.,Center for Computational and Integrative Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Christian T Covington
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.,Center for Computational and Integrative Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Mathilde Poyet
- Center for Microbiome Informatics and Therapeutics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Jessica Crothers
- Department of Pathology and Laboratory Medicine, University of Vermont Medical Center, Burlington, VT 05401, USA
| | - Peter L Moses
- Division of Gastroenterology and Hepatology, University of Vermont, Burlington, VT 05401, USA
| | - Andrew C Tolonen
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.,Center for Computational and Integrative Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Hera Vlamakis
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.,Center for Computational and Integrative Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Eric J Alm
- Center for Microbiome Informatics and Therapeutics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. .,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Ramnik J Xavier
- Center for Microbiome Informatics and Therapeutics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. .,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.,Center for Computational and Integrative Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.,Gastrointestinal Unit and Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
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49
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Blum P, Payne S. Evidence of an Epigenetics System in Archaea. Epigenet Insights 2019; 12:2516865719865280. [PMID: 31384725 PMCID: PMC6664620 DOI: 10.1177/2516865719865280] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 07/01/2019] [Indexed: 12/17/2022] Open
Abstract
Changes in the phenotype of a cell or organism that are heritable but do not
involve changes in DNA sequence are referred to as epigenetic. They occur
primarily through the gain or loss of chemical modification of chromatin protein
or DNA. Epigenetics is therefore a non-Mendelian process. The study of
epigenetics in eukaryotes is expanding with advances in knowledge about the
relationship between mechanism and phenotype and as a requirement for
multicellularity and cancer. However, life also includes other groups or
domains, notably the bacteria and archaea. The occurrence of epigenetics in
these deep lineages is an emerging topic accompanied by controversy. In these
non-eukaryotic organisms, epigenetics is critically important because it
stimulates new evolutionary theory and refines perspective about biological
action.
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Affiliation(s)
- Paul Blum
- School of Biological Science, University of Nebraska-Lincoln, Lincoln, NE, USA.,Department of Microbiology and Toxicology, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Sophie Payne
- School of Biological Science, University of Nebraska-Lincoln, Lincoln, NE, USA.,Department of Microbiology and Toxicology, University of California Santa Cruz, Santa Cruz, CA, USA
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50
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Biofilm-Constructing Variants of Paraburkholderia phytofirmans PsJN Outcompete the Wild-Type Form in Free-Living and Static Conditions but Not In Planta. Appl Environ Microbiol 2019; 85:AEM.02670-18. [PMID: 30902863 DOI: 10.1128/aem.02670-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 03/09/2019] [Indexed: 11/20/2022] Open
Abstract
Members of the genus Burkholderia colonize diverse ecological niches. Among the plant-associated strains, Paraburkholderia phytofirmans PsJN is an endophyte with a broad host range. In a spatially structured environment (unshaken broth cultures), biofilm-constructing specialists of P. phytofirmans PsJN colonizing the air-liquid interface arose at high frequency. In addition to forming a robust biofilm in vitro and in planta on Arabidopsis roots, those mucoid phenotypic variants display a reduced swimming ability and modulate the expression of several microbe-associated molecular patterns (MAMPs), including exopolysaccharides (EPS), flagellin, and GroEL. Interestingly, the variants induce low PR1 and PDF1.2 expression compared to that of the parental strain, suggesting a possible evasion of plant host immunity. We further demonstrated that switching from the planktonic to the sessile form did not involve quorum-sensing genes but arose from spontaneous mutations in two genes belonging to an iron-sulfur cluster: hscA (encoding a cochaperone protein) and iscS (encoding a cysteine desulfurase). A mutational approach validated the implication of these two genes in the appearance of variants. We showed for the first time that in a heterogeneous environment, P. phytofirmans strain PsJN is able to rapidly diversify and coexpress a variant that outcompete the wild-type form in free-living and static conditions but not in planta IMPORTANCE Paraburkholderia phytofirmans strain PsJN is a well-studied plant-associated bacterium known to induce resistance against biotic and abiotic stresses. In this work, we described the spontaneous appearance of mucoid variants in PsJN from static cultures. We showed that the conversion from the wild-type (WT) form to variants (V) correlates with an overproduction of EPS, an enhanced ability to form biofilm in vitro and in planta, and a reduced swimming motility. Our results revealed also that these phenotypes are in part associated with spontaneous mutations in an iron-sulfur cluster. Overall, the data provided here allow a better understanding of the adaptive mechanisms likely developed by P. phytofirmans PsJN in a heterogeneous environment.
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