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Itoh K, Matsueda S. Exploring the Potential of Humoral Immune Response to Commensal Bifidobacterium as a Biomarker for Human Health, including Both Malignant and Non-Malignant Diseases: A Perspective on Detection Strategies and Future Directions. Biomedicines 2024; 12:803. [PMID: 38672158 PMCID: PMC11048515 DOI: 10.3390/biomedicines12040803] [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: 10/24/2023] [Revised: 03/24/2024] [Accepted: 03/26/2024] [Indexed: 04/28/2024] Open
Abstract
In this comprehensive review, we explore the pivotal role of commensal Bifidobacterium (c-BIF) as potent non-self-antigens through antigenic mimicry, along with exploring the potential of humoral immune responses for both malignant and non-malignant disease. c-BIF, a predominant component of the human gut microbiome encompassing around 90% of the human genome, has emerged as a pivotal player in human biology. Over recent decades, there has been extensive research elucidating the intricate connections between c-BIF and various facets of human health, with particular emphasis on their groundbreaking impact on anti-cancer effects and the management of non-malignant diseases. The multifaceted role of c-BIF is explored, ranging from enhancing anti-tumor immunity to improving the efficacy of anti-cancer and anti-infectious disease strategies, and serving as predictive biomarkers for various diseases. Recent studies highlight not only c-BIF's promotion of anti-tumor immunity but also their role in enhancing the efficacy of immune checkpoint inhibitors. The review emphasizes the promising avenue of manipulating the gut microbiota, particularly c-BIF, for modulating cancer immunotherapy with targeted effects on tumor cells while minimizing harm to normal tissue. In the context of infectious and inflammatory diseases, the crucial role of c-BIFs in the management of COVID-19 symptoms is examined, emphasizing their impact on the severity of and immune response to COVID-19. Furthermore, c-BIF exhibits preventive and therapeutic effects on Human Papillomaviruses (HPV) and shows promise in improving inflammatory bowel diseases. The potential application of c-BIF as a biomarker for immunotherapy is explored, with a specific emphasis on its predictive and prognostic value in cancer. Suggestions are made regarding the use of humoral immune responses to cytotoxic T lymphocyte (CTL) epitope peptides that share motifs with c-BIF, proposing them as potential markers for predicting overall survival in diverse cancer patients. In conclusion, c-BIF emerges as a crucial and multifaceted determinant of human health, across anti-tumor immunity to infectious and inflammatory disease management. The manipulation of c-BIF and gut microbiota presents a promising avenue for advancing therapeutic strategies, particularly in the realm of cancer immunotherapy. Additionally, this review highlights the significance of c-BIF as potent non-self-antigens via antigenic mimicry, emphasizing the importance of robust humoral immune responses against c-BIF for preventing various diseases, including inflammatory conditions. Elevated levels of circulating antibodies against c-BIF in healthy individuals may serve as potential indicators of lower risks for malignant and non-malignant diseases.
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Affiliation(s)
| | - Satoko Matsueda
- Cancer Vaccine Center, Kurume University, Kurume 839-0863, Japan
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2
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Han X, Chang L, Chen H, Zhao J, Tian F, Ross RP, Stanton C, van Sinderen D, Chen W, Yang B. Harnessing the endogenous Type I-C CRISPR-Cas system for genome editing in Bifidobacterium breve. Appl Environ Microbiol 2024; 90:e0207423. [PMID: 38319094 PMCID: PMC10952402 DOI: 10.1128/aem.02074-23] [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: 11/27/2023] [Accepted: 01/14/2024] [Indexed: 02/07/2024] Open
Abstract
Bifidobacterium breve, one of the main bifidobacterial species colonizing the human gastrointestinal tract in early life, has received extensive attention for its purported beneficial effects on human health. However, exploration of the mode of action of such beneficial effects exerted by B. breve is cumbersome due to the lack of effective genetic tools, which limits its synthetic biology application. The widespread presence of CRISPR-Cas systems in the B. breve genome makes endogenous CRISPR-based gene editing toolkits a promising tool. This study revealed that Type I-C CRISPR-Cas systems in B. breve can be divided into two groups based on the amino acid sequences encoded by cas gene clusters. Deletion of the gene coding uracil phosphoribosyl-transferase (upp) was achieved in five B. breve strains from both groups using this system. In addition, translational termination of uracil phosphoribosyl-transferase was successfully achieved in B. breve FJSWX38M7 by single-base substitution of the upp gene and insertion of three stop codons. The gene encoding linoleic acid isomerase (bbi) in B. breve, being a characteristic trait, was deleted after plasmid curing, which rendered it unable to convert linoleic acid into conjugated linoleic acid, demonstrating the feasibility of successive editing. This study expands the toolkit for gene manipulation in B. breve and provides a new approach toward functional genome editing and analysis of B. breve strains.IMPORTANCEThe lack of effective genetic tools for Bifidobacterium breve is an obstacle to studying the molecular mechanisms of its health-promoting effects, hindering the development of next-generation probiotics. Here, we introduce a gene editing method based on the endogenous CRISPR-Cas system, which can achieve gene deletion, single-base substitution, gene insertion, and successive gene editing in B. breve. This study will facilitate discovery of functional genes and elucidation of molecular mechanisms of B. breve pertaining to health-associated benefits.
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Affiliation(s)
- Xiao Han
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Lulu Chang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Haiqin Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Jianxin Zhao
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
| | - Fengwei Tian
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
- International Joint Research Center for Probiotics & Gut Health, Jiangnan University, Wuxi, Jiangsu, China
| | - R. Paul Ross
- International Joint Research Center for Probiotics & Gut Health, Jiangnan University, Wuxi, Jiangsu, China
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Catherine Stanton
- International Joint Research Center for Probiotics & Gut Health, Jiangnan University, Wuxi, Jiangsu, China
- Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
| | | | - Wei Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu, China
| | - Bo Yang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China
- International Joint Research Center for Probiotics & Gut Health, Jiangnan University, Wuxi, Jiangsu, China
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3
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Shiver AL, Sun J, Culver R, Violette A, Wynter C, Nieckarz M, Mattiello SP, Sekhon PK, Friess L, Carlson HK, Wong D, Higginbottom S, Weglarz M, Wang W, Knapp BD, Guiberson E, Sanchez J, Huang PH, Garcia PA, Buie CR, Good B, DeFelice B, Cava F, Scaria J, Sonnenburg J, Sinderen DV, Deutschbauer AM, Huang KC. A mutant fitness compendium in Bifidobacteria reveals molecular determinants of colonization and host-microbe interactions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.29.555234. [PMID: 37693407 PMCID: PMC10491234 DOI: 10.1101/2023.08.29.555234] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Bifidobacteria commonly represent a dominant constituent of human gut microbiomes during infancy, influencing nutrition, immune development, and resistance to infection. Despite interest as a probiotic therapy, predicting the nutritional requirements and health-promoting effects of Bifidobacteria is challenging due to major knowledge gaps. To overcome these deficiencies, we used large-scale genetics to create a compendium of mutant fitness in Bifidobacterium breve (Bb). We generated a high density, randomly barcoded transposon insertion pool in Bb, and used this pool to determine Bb fitness requirements during colonization of germ-free mice and chickens with multiple diets and in response to hundreds of in vitro perturbations. To enable mechanistic investigation, we constructed an ordered collection of insertion strains covering 1462 genes. We leveraged these tools to improve models of metabolic pathways, reveal unexpected host- and diet-specific requirements for colonization, and connect the production of immunomodulatory molecules to growth benefits. These resources will greatly reduce the barrier to future investigations of this important beneficial microbe.
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Affiliation(s)
- Anthony L. Shiver
- Department of Bioengineering, Stanford University, Stanford CA 94305, USA
| | - Jiawei Sun
- Department of Bioengineering, Stanford University, Stanford CA 94305, USA
| | - Rebecca Culver
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Arvie Violette
- Department of Bioengineering, Stanford University, Stanford CA 94305, USA
| | - Charles Wynter
- Department of Bioengineering, Stanford University, Stanford CA 94305, USA
| | - Marta Nieckarz
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, SE-90187, Sweden
| | - Samara Paula Mattiello
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD, 57007, USA
- College of Mathematics and Science, The University of Tennessee Southern, Pulaski TN 38478, USA
| | - Prabhjot Kaur Sekhon
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD, 57007, USA
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK, 74074, USA
| | - Lisa Friess
- School of Microbiology, University College Cork, Ireland
- APC Microbiome Ireland, University College Cork, Ireland
| | - Hans K. Carlson
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Daniel Wong
- Department of Applied Physics, Stanford University, Stanford CA 94305, USA
| | - Steven Higginbottom
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Meredith Weglarz
- Stanford Shared FACS Facility, Center for Molecular and Genetic Medicine, Stanford University, Stanford, California, USA
| | - Weigao Wang
- Department of Chemical Engineering, Stanford University, Stanford CA 94305, USA
| | | | - Emma Guiberson
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Po-Hsun Huang
- Department of Mechanical Engineering, Laboratory for Energy and Microsystems Innovation, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, 02139, MA, USA
| | - Paulo A. Garcia
- Department of Mechanical Engineering, Laboratory for Energy and Microsystems Innovation, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, 02139, MA, USA
| | - Cullen R. Buie
- Department of Mechanical Engineering, Laboratory for Energy and Microsystems Innovation, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, 02139, MA, USA
| | - Benjamin Good
- Department of Applied Physics, Stanford University, Stanford CA 94305, USA
| | | | - Felipe Cava
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, SE-90187, Sweden
| | - Joy Scaria
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD, 57007, USA
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK, 74074, USA
| | - Justin Sonnenburg
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Douwe Van Sinderen
- School of Microbiology, University College Cork, Ireland
- APC Microbiome Ireland, University College Cork, Ireland
| | - Adam M. Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford CA 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
- Chan-Zuckerberg Biohub, San Francisco, CA 94158
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4
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Ortiz Camargo AR, van Mastrigt O, Bongers RS, Ben-Amor K, Knol J, Abee T, Smid EJ. Quantitative Physiology and Proteome Adaptations of Bifidobacterium breve NRBB57 at Near-Zero Growth Rates. Microbiol Spectr 2023; 11:e0256822. [PMID: 37184421 PMCID: PMC10269484 DOI: 10.1128/spectrum.02568-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 04/26/2023] [Indexed: 05/16/2023] Open
Abstract
In natural environments, nutrients are usually scarce, causing microorganisms to grow slowly while staying metabolically active. These natural conditions can be simulated using retentostat cultivations. The present study describes the physiological and proteome adaptations of the probiotic Bifidobacterium breve NRBB57 from high (0.4 h-1) to near-zero growth rates. Lactose-limited retentostat cultivations were carried out for 21 days in which the bacterial growth rate progressively reduced to 0.00092 h-1, leading to a 3.4-fold reduction of the maintenance energy requirement. Lactose was mainly converted into acetate, formate, and ethanol at high growth rates, while in the retentostat, lactate production increased. Interestingly, the consumption of several amino acids (serine, aspartic acid, and glutamine/arginine) and glycerol increased over time in the retentostat. Morphological changes and viable but nonculturable cells were also observed in the retentostat. Proteomes were compared for all growth rates, revealing a downregulation of ribosomal proteins at near-zero growth rates and an upregulation of proteins involved in the catabolism of alternative energy sources. Finally, we observed induction of the stringent response and stress defense systems. Retentostat cultivations were proven useful to study the physiology of B. breve, mimicking the nutrient scarcity of its complex habitat, the human gut. IMPORTANCE In natural environments, nutrients are usually scarce, causing microorganisms to grow slowly while staying metabolically active. In this study we used retentostat cultivation to investigate how the probiotic Bifidobacterium breve adapts its physiology and proteome under severe nutrient limitation resulting in near-zero growth rates (<0.001 h-1). We showed that the nutrient limitation induced a multifaceted response including stress defense and stringent response, metabolic shifts, and the activation of novel alternative energy-producing pathways.
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Affiliation(s)
| | - Oscar van Mastrigt
- Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | | | | | - Jan Knol
- Danone Nutricia Research, Utrecht, The Netherlands
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Tjakko Abee
- Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Eddy J. Smid
- Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands
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5
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Camargo ARO, Van Mastrigt O, Bongers RS, Ben-Amor K, Knol J, Smid EJ, Abee T. Enhanced stress resistance of Bifidobacterium breve NRBB57 by induction of stress proteins at near-zero growth rates. Benef Microbes 2023; 14:85-94. [PMID: 36790092 DOI: 10.3920/bm2022.0074] [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: 02/16/2023]
Abstract
Bifidobacterium breve is a common habitant of the human gut and is used as probiotic in functional foods. B. breve has to cope with multiple stress conditions encountered during processing and passage through the human gut, including high temperature, low pH and exposure to oxygen. Additionally, during industrial processing and in the gut, B. breve could encounter nutrient limitation resulting in reduced growth rates that can trigger adaptive stress responses. For this reason, it is important to develop culture methods that elicit resistance to multiple stresses (robustness) encountered by the bacteria. To investigate the impact of caloric restriction on robustness of the probiotic B. breve NRBB57, this strain was grown in lactose-limited chemostat cultures and in retentostat for 21 days, at growth rates ranging from 0.4 h-1 to 0.00081 h-1. Proteomes of cells harvested at different growth rates were correlated to acid, hydrogen peroxide and heat stress survival capacity. Comparative proteome analysis showed that retentostat-grown cells had significantly increased abundance of a variety of stress proteins involved in protein quality maintenance and DNA repair (DnaJ, Hsp90, FtsH, ClpB, ClpP1, ClpC, GroES, RuvB, RecA), as well as proteins involved in oxidative stress defence (peroxiredoxin, ferredoxin, thioredoxin peroxidase, glutaredoxin and thioredoxin reductase). Exposure to three different stress conditions, 45 °C, pH 3, and 10 mM H2O2, showed highest stress resistance of retentostat cells sampled at week 2 and week 3 grown at 0.0018 and 0.00081 h-1. Our findings show that cultivation at near-zero growth rates induces higher abundance of stress defence proteins contributing to the robustness of B. breve NRBB57, thereby offering an approach that may support its production and functionality.
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Affiliation(s)
- A R Ortiz Camargo
- Food Microbiology, Wageningen University & Research, P.O. box 17, 6700 AA Wageningen, The Netherlands
| | - O Van Mastrigt
- Food Microbiology, Wageningen University & Research, P.O. box 17, 6700 AA Wageningen, The Netherlands
| | - R S Bongers
- Danone Nutricia Research, Uppsalalaan 12, 3584 CT Utrecht, the Netherlands
| | - K Ben-Amor
- Danone Nutricia Research, Uppsalalaan 12, 3584 CT Utrecht, the Netherlands
| | - J Knol
- Danone Nutricia Research, Uppsalalaan 12, 3584 CT Utrecht, the Netherlands.,Laboratory of Microbiology, Wageningen University & Research, P.O. Box 8033, 6700 EH Wageningen, the Netherlands
| | - E J Smid
- Food Microbiology, Wageningen University & Research, P.O. box 17, 6700 AA Wageningen, The Netherlands
| | - T Abee
- Food Microbiology, Wageningen University & Research, P.O. box 17, 6700 AA Wageningen, The Netherlands
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6
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Metters G, Hemsley C, Norville I, Titball R. Identification of essential genes in Coxiella burnetii. Microb Genom 2023; 9:mgen000944. [PMID: 36723494 PMCID: PMC9997736 DOI: 10.1099/mgen.0.000944] [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: 02/02/2023] Open
Abstract
Coxiella burnetii is an intracellular pathogen responsible for causing Q fever in humans, a disease with varied presentations ranging from a mild flu-like sickness to a debilitating illness that can result in endocarditis. The intracellular lifestyle of C. burnetii is unique, residing in an acidic phagolysosome-like compartment within host cells. An understanding of the core molecular biology of C. burnetii will greatly increase our understanding of C. burnetii growth, survival and pathogenesis. We used transposon-directed insertion site sequencing (TraDIS) to reveal C. burnetii Nine Mile Phase II genes fundamental for growth and in vitro survival. Screening a transposon library containing >10 000 unique transposon mutants revealed 512 predicted essential genes. Essential routes of synthesis were identified for the mevalonate pathway, as well as peptidoglycan and biotin synthesis. Some essential genes identified (e.g. predicted type IV secretion system effector genes) are typically considered to be associated with C. burnetii virulence, a caveat concerning the axenic media used in the study. Investigation into the conservation of the essential genes identified revealed that 78 % are conserved across all C. burnetii strains sequenced to date, which probably play critical functions. This is the first report of a whole genome transposon screen in C. burnetii that has been undertaken for the identification of essential genes.
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Affiliation(s)
- Georgie Metters
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK.,Defence Science and Technology Laboratories, CBR Division, Porton Down, Salisbury SP4 0JQ, UK
| | - Claudia Hemsley
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK.,Present address: Molecular Microbiology Division, School of Life Sciences, University of Dundee, Dundee, DD1 5AA, UK
| | - Isobel Norville
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK.,Defence Science and Technology Laboratories, CBR Division, Porton Down, Salisbury SP4 0JQ, UK
| | - Richard Titball
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK
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7
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Huang PH, Chen S, Shiver AL, Culver RN, Huang KC, Buie CR. M-TUBE enables large-volume bacterial gene delivery using a high-throughput microfluidic electroporation platform. PLoS Biol 2022; 20:e3001727. [PMID: 36067229 PMCID: PMC9481174 DOI: 10.1371/journal.pbio.3001727] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 09/16/2022] [Accepted: 06/24/2022] [Indexed: 11/19/2022] Open
Abstract
Conventional cuvette-based and microfluidics-based electroporation approaches for bacterial gene delivery have distinct advantages, but they are typically limited to relatively small sample volumes, reducing their utility for applications requiring high throughput such as the generation of mutant libraries. Here, we present a scalable, large-scale bacterial gene delivery approach enabled by a disposable, user-friendly microfluidic electroporation device requiring minimal device fabrication and straightforward operation. We demonstrate that the proposed device can outperform conventional cuvettes in a range of situations, including across Escherichia coli strains with a range of electroporation efficiencies, and we use its large-volume bacterial electroporation capability to generate a library of transposon mutants in the anaerobic gut commensal Bifidobacterium longum.
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Affiliation(s)
- Po-Hsun Huang
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Sijie Chen
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Anthony L. Shiver
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Rebecca Neal Culver
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- Chan Zuckerberg Biohub, San Francisco, California, United States of America
| | - Cullen R. Buie
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
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8
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Maximum depth sequencing reveals an ON/OFF replication slippage switch and apparent in vivo selection for bifidobacterial pilus expression. Sci Rep 2022; 12:9576. [PMID: 35688912 PMCID: PMC9187656 DOI: 10.1038/s41598-022-13668-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 05/16/2022] [Indexed: 11/09/2022] Open
Abstract
The human gut microbiome, of which the genus Bifidobacterium is a prevalent and abundant member, is thought to sustain and enhance human health. Several surface-exposed structures, including so-called sortase-dependent pili, represent important bifidobacterial gut colonization factors. Here we show that expression of two sortase-dependent pilus clusters of the prototype Bifidobacterium breve UCC2003 depends on replication slippage at an intragenic G-tract, equivalents of which are present in various members of the Bifidobacterium genus. The nature and extent of this slippage is modulated by the host environment. Involvement of such sortase-dependent pilus clusters in microbe-host interactions, including bacterial attachment to the gut epithelial cells, has been shown previously and is corroborated here for one case. Using a Maximum Depth Sequencing strategy aimed at excluding PCR and sequencing errors introduced by DNA polymerase reagents, specific G-tract sequences in B. breve UCC2003 reveal a range of G-tract lengths whose plasticity within the population is functionally utilized. Interestingly, replication slippage is shown to be modulated under in vivo conditions in a murine model. This in vivo modulation causes an enrichment of a G-tract length which appears to allow biosynthesis of these sortase-dependent pili. This work provides the first example of productive replication slippage influenced by in vivo conditions. It highlights the potential for microdiversity generation in “beneficial” gut commensals.
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9
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Luo H, Lin Y, Liu T, Lai FL, Zhang CT, Gao F, Zhang R. DEG 15, an update of the Database of Essential Genes that includes built-in analysis tools. Nucleic Acids Res 2021; 49:D677-D686. [PMID: 33095861 PMCID: PMC7779065 DOI: 10.1093/nar/gkaa917] [Citation(s) in RCA: 90] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 09/30/2020] [Accepted: 10/06/2020] [Indexed: 12/21/2022] Open
Abstract
Essential genes refer to genes that are required by an organism to survive under specific conditions. Studies of the minimal-gene-set for bacteria have elucidated fundamental cellular processes that sustain life. The past five years have seen a significant progress in identifying human essential genes, primarily due to the successful use of CRISPR/Cas9 in various types of human cells. DEG 15, a new release of the Database of Essential Genes (www.essentialgene.org), has provided major advancements, compared to DEG 10. Specifically, the number of eukaryotic essential genes has increased by more than fourfold, and that of prokaryotic ones has more than doubled. Of note, the human essential-gene number has increased by more than tenfold. Moreover, we have developed built-in analysis modules by which users can perform various analyses, such as essential-gene distributions between bacterial leading and lagging strands, sub-cellular localization distribution, enrichment analysis of gene ontology and KEGG pathways, and generation of Venn diagrams to compare and contrast gene sets between experiments. Additionally, the database offers customizable BLAST tools for performing species- and experiment-specific BLAST searches. Therefore, DEG comprehensively harbors updated human-curated essential-gene records among prokaryotes and eukaryotes with built-in tools to enhance essential-gene analysis.
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Affiliation(s)
- Hao Luo
- Department of Physics, School of Science, Tianjin University, Tianjin 300072, China
| | - Yan Lin
- Department of Physics, School of Science, Tianjin University, Tianjin 300072, China
| | - Tao Liu
- Department of Physics, School of Science, Tianjin University, Tianjin 300072, China
| | - Fei-Liao Lai
- Department of Physics, School of Science, Tianjin University, Tianjin 300072, China
| | - Chun-Ting Zhang
- Department of Physics, School of Science, Tianjin University, Tianjin 300072, China
| | - Feng Gao
- Department of Physics, School of Science, Tianjin University, Tianjin 300072, China.,Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China
| | - Ren Zhang
- Center for Molecular Medicine and Genetics, School of Medicine, Wayne State University, Detroit, MI 48201, USA
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10
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Engineer probiotic bifidobacteria for food and biomedical applications - Current status and future prospective. Biotechnol Adv 2020; 45:107654. [DOI: 10.1016/j.biotechadv.2020.107654] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 09/14/2020] [Accepted: 11/01/2020] [Indexed: 12/15/2022]
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11
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Solopova A, Bottacini F, Venturi Degli Esposti E, Amaretti A, Raimondi S, Rossi M, van Sinderen D. Riboflavin Biosynthesis and Overproduction by a Derivative of the Human Gut Commensal Bifidobacterium longum subsp. infantis ATCC 15697. Front Microbiol 2020; 11:573335. [PMID: 33042083 PMCID: PMC7522473 DOI: 10.3389/fmicb.2020.573335] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/17/2020] [Indexed: 11/18/2022] Open
Abstract
Riboflavin or vitamin B2 is the precursor of the essential coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). Despite increased interest in microbial synthesis of this water-soluble vitamin, the metabolic pathway for riboflavin biosynthesis has been characterized in just a handful of bacteria. Here, comparative genome analysis identified the genes involved in the de novo biosynthetic pathway of riboflavin in certain bifidobacterial species, including the human gut commensal Bifidobacterium longum subsp. infantis (B. infantis) ATCC 15697. Using comparative genomics and phylogenomic analysis, we investigated the evolutionary acquisition route of the riboflavin biosynthesis or rib gene cluster in Bifidobacterium and the distribution of riboflavin biosynthesis-associated genes across the genus. Using B. infantis ATCC 15697 as model organism for this pathway, we isolated spontaneous riboflavin overproducers, which had lost transcriptional regulation of the genes required for riboflavin biosynthesis. Among them, one mutant was shown to allow riboflavin release into the medium to a concentration of 60.8 ng mL–1. This mutant increased vitamin B2 concentration in a fecal fermentation system, thus providing promising data for application of this isolate as a functional food ingredient.
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Affiliation(s)
- Ana Solopova
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | | | | | - Alberto Amaretti
- Department of Chemistry, University of Modena and Reggio Emilia, Modena, Italy.,BIOGEST-SITEIA, University of Modena and Reggio Emilia, Modena, Italy
| | - Stefano Raimondi
- Department of Chemistry, University of Modena and Reggio Emilia, Modena, Italy
| | - Maddalena Rossi
- Department of Chemistry, University of Modena and Reggio Emilia, Modena, Italy.,BIOGEST-SITEIA, University of Modena and Reggio Emilia, Modena, Italy
| | - Douwe van Sinderen
- APC Microbiome Ireland, University College Cork, Cork, Ireland.,School of Microbiology, University College Cork, Cork, Ireland
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12
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Abstract
The goal of genomics and systems biology is to understand how complex systems of factors assemble into pathways and structures that combine to form living organisms. Great advances in understanding biological processes result from determining the function of individual genes, a process that has classically relied on characterizing single mutations. Advances in DNA sequencing has made available the complete set of genetic instructions for an astonishing and growing number of species. To understand the function of this ever-increasing number of genes, a high-throughput method was developed that in a single experiment can measure the function of genes across the genome of an organism. This occurred approximately 10 years ago, when high-throughput DNA sequencing was combined with advances in transposon-mediated mutagenesis in a method termed transposon insertion sequencing (TIS). In the subsequent years, TIS succeeded in addressing fundamental questions regarding the genes of bacteria, many of which have been shown to play central roles in bacterial infections that result in major human diseases. The field of TIS has matured and resulted in studies of hundreds of species that include significant innovations with a number of transposons. Here, we summarize a number of TIS experiments to provide an understanding of the method and explanation of approaches that are instructive when designing a study. Importantly, we emphasize critical aspects of a TIS experiment and highlight the extension and applicability of TIS into nonbacterial species such as yeast.
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Affiliation(s)
- Tim van Opijnen
- Department of Biology, Boston College, Chestnut Hill, Massachusetts 02467, USA;
| | - Henry L Levin
- Section on Eukaryotic Transposable Elements, Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA;
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13
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AlbaTraDIS: Comparative analysis of large datasets from parallel transposon mutagenesis experiments. PLoS Comput Biol 2020; 16:e1007980. [PMID: 32678849 PMCID: PMC7390408 DOI: 10.1371/journal.pcbi.1007980] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 07/29/2020] [Accepted: 05/23/2020] [Indexed: 12/11/2022] Open
Abstract
Bacteria need to survive in a wide range of environments. Currently, there is an incomplete understanding of the genetic basis for mechanisms underpinning survival in stressful conditions, such as the presence of anti-microbials. Transposon directed insertion-site sequencing (TraDIS) is a powerful tool to identify genes and networks which are involved in survival and fitness under a given condition by simultaneously assaying the fitness of millions of mutants, thereby relating genotype to phenotype and contributing to an understanding of bacterial cell biology. A recent refinement of this approach allows the roles of essential genes in conditional stress survival to be inferred by altering their expression. These advancements combined with the rapidly falling costs of sequencing now allows comparisons between multiple experiments to identify commonalities in stress responses to different conditions. This capacity however poses a new challenge for analysis of multiple data sets in conjunction. To address this analysis need, we have developed ‘AlbaTraDIS’; a software application for rapid large-scale comparative analysis of TraDIS experiments that predicts the impact of transposon insertions on nearby genes. AlbaTraDIS can identify genes which are up or down regulated, or inactivated, between multiple conditions, producing a filtered list of genes for further experimental validation as well as several accompanying data visualisations. We demonstrate the utility of our new approach by applying it to identify genes used by Escherichia coli to survive in a wide range of different concentrations of the biocide Triclosan. AlbaTraDIS identified all well characterised Triclosan resistance genes, including the primary target, fabI. A number of new loci were also implicated in Triclosan resistance and the predicted phenotypes for a selection of these were validated experimentally with results being consistent with predictions. AlbaTraDIS provides a simple and rapid method to analyse multiple transposon mutagenesis data sets allowing this technology to be used at large scale. To our knowledge this is the only tool currently available that can perform these tasks. AlbaTraDIS is written in Python 3 and is available under the open source licence GNU GPL 3 from https://github.com/quadram-institute-bioscience/albatradis.
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14
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Cain AK, Barquist L, Goodman AL, Paulsen IT, Parkhill J, van Opijnen T. A decade of advances in transposon-insertion sequencing. Nat Rev Genet 2020; 21:526-540. [PMID: 32533119 PMCID: PMC7291929 DOI: 10.1038/s41576-020-0244-x] [Citation(s) in RCA: 191] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/24/2020] [Indexed: 01/12/2023]
Abstract
It has been 10 years since the introduction of modern transposon-insertion sequencing (TIS) methods, which combine genome-wide transposon mutagenesis with high-throughput sequencing to estimate the fitness contribution or essentiality of each genetic component in a bacterial genome. Four TIS variations were published in 2009: transposon sequencing (Tn-Seq), transposon-directed insertion site sequencing (TraDIS), insertion sequencing (INSeq) and high-throughput insertion tracking by deep sequencing (HITS). TIS has since become an important tool for molecular microbiologists, being one of the few genome-wide techniques that directly links phenotype to genotype and ultimately can assign gene function. In this Review, we discuss the recent applications of TIS to answer overarching biological questions. We explore emerging and multidisciplinary methods that build on TIS, with an eye towards future applications. In this Review, several experts discuss progress in the decade since the development of transposon-based approaches for bacterial genetic screens. They describe how advances in both experimental technologies and analytical strategies are resulting in insights into diverse biological processes.
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Affiliation(s)
- Amy K Cain
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia.
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany.,Faculty of Medicine, University of Würzburg, Würzburg, Germany
| | - Andrew L Goodman
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, New Haven, CT, USA
| | - Ian T Paulsen
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
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15
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Lanigan N, Kelly E, Arzamasov AA, Stanton C, Rodionov DA, van Sinderen D. Transcriptional control of central carbon metabolic flux in Bifidobacteria by two functionally similar, yet distinct LacI-type regulators. Sci Rep 2019; 9:17851. [PMID: 31780796 PMCID: PMC6882875 DOI: 10.1038/s41598-019-54229-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 11/06/2019] [Indexed: 12/21/2022] Open
Abstract
Bifidobacteria resident in the gastrointestinal tract (GIT) are subject to constantly changing environmental conditions, which require rapid adjustments in gene expression. Here, we show that two predicted LacI-type transcription factors (TFs), designated AraQ and MalR1, are involved in regulating the central, carbohydrate-associated metabolic pathway (the so-called phosphoketolase pathway or bifid shunt) of the gut commensal Bifidobacterium breve UCC2003. These TFs appear to not only control transcription of genes involved in the bifid shunt and each other, but also seem to commonly and directly affect transcription of other TF-encoding genes, as well as genes related to uptake and metabolism of various carbohydrates. This complex and interactive network of AraQ/MalR1-mediated gene regulation provides previously unknown insights into the governance of carbon metabolism in bifidobacteria.
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Affiliation(s)
- Noreen Lanigan
- School of Microbiology & APC Microbiome Ireland, University College Cork, Ireland University College Cork, Cork, Ireland
| | - Emer Kelly
- School of Microbiology & APC Microbiome Ireland, University College Cork, Ireland University College Cork, Cork, Ireland
| | - Aleksandr A Arzamasov
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, United States.,A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | | | - Dmitry A Rodionov
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, United States.,A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Douwe van Sinderen
- School of Microbiology & APC Microbiome Ireland, University College Cork, Ireland University College Cork, Cork, Ireland.
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16
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Bottacini F, Morrissey R, Roberts R, James K, van Breen J, Egan M, Lambert J, van Limpt K, Knol J, Motherway M, van Sinderen D. Comparative genome and methylome analysis reveals restriction/modification system diversity in the gut commensal Bifidobacterium breve. Nucleic Acids Res 2019; 46:1860-1877. [PMID: 29294107 PMCID: PMC5829577 DOI: 10.1093/nar/gkx1289] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 12/18/2017] [Indexed: 11/12/2022] Open
Abstract
Bifidobacterium breve represents one of the most abundant bifidobacterial species in the gastro-intestinal tract of breast-fed infants, where their presence is believed to exert beneficial effects. In the present study whole genome sequencing, employing the PacBio Single Molecule, Real-Time (SMRT) sequencing platform, combined with comparative genome analysis allowed the most extensive genetic investigation of this taxon. Our findings demonstrate that genes encoding Restriction/Modification (R/M) systems constitute a substantial part of the B. breve variable gene content (or variome). Using the methylome data generated by SMRT sequencing, combined with targeted Illumina bisulfite sequencing (BS-seq) and comparative genome analysis, we were able to detect methylation recognition motifs and assign these to identified B. breve R/M systems, where in several cases such assignments were confirmed by restriction analysis. Furthermore, we show that R/M systems typically impose a very significant barrier to genetic accessibility of B. breve strains, and that cloning of a methyltransferase-encoding gene may overcome such a barrier, thus allowing future functional investigations of members of this species.
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Affiliation(s)
- Francesca Bottacini
- APC Microbiome Institute & Department of Microbiology, National University of Ireland, Cork, Ireland
| | - Ruth Morrissey
- APC Microbiome Institute & Department of Microbiology, National University of Ireland, Cork, Ireland
| | | | - Kieran James
- APC Microbiome Institute & Department of Microbiology, National University of Ireland, Cork, Ireland
| | - Justin van Breen
- APC Microbiome Institute & Department of Microbiology, National University of Ireland, Cork, Ireland
| | - Muireann Egan
- APC Microbiome Institute & Department of Microbiology, National University of Ireland, Cork, Ireland
| | | | | | - Jan Knol
- Nutricia Research, Utrecht, the Netherlands
- Laboratory of Microbiology, Wageningen Univerisity, Wageningen
| | - Mary O’Connell Motherway
- APC Microbiome Institute & Department of Microbiology, National University of Ireland, Cork, Ireland
| | - Douwe van Sinderen
- APC Microbiome Institute & Department of Microbiology, National University of Ireland, Cork, Ireland
- To whom correspondence should be addressed. Tel: +353 21 4901365; Fax: +353 21 4903101;
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17
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A Transposon Mutagenesis System for Bifidobacterium longum subsp. longum Based on an IS 3 Family Insertion Sequence, IS Blo11. Appl Environ Microbiol 2018; 84:AEM.00824-18. [PMID: 29934330 DOI: 10.1128/aem.00824-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 06/16/2018] [Indexed: 12/29/2022] Open
Abstract
Bifidobacteria are a major component of the intestinal microbiota in humans, particularly breast-fed infants. Therefore, elucidation of the mechanisms by which these bacteria colonize the intestine is desired. One approach is transposon mutagenesis, a technique currently attracting much attention because, in combination with next-generation sequencing, it enables exhaustive identification of genes that contribute to microbial fitness. We now describe a transposon mutagenesis system for Bifidobacterium longum subsp. longum 105-A (JCM 31944) based on ISBlo11, a native IS3 family insertion sequence. To build this system, xylose-inducible or constitutive bifidobacterial promoters were tested to drive the expression of full-length or a truncated form at the N terminus of the ISBlo11 transposase. An artificial transposon plasmid, pBFS12, in which ISBlo11 terminal inverted repeats are separated by a 3-bp spacer, was also constructed to mimic the transposition intermediate of IS3 elements. The introduction of this plasmid into a strain expressing transposase resulted in the insertion of the plasmid with an efficiency of >103 CFU/μg DNA. The plasmid targets random 3- to 4-bp sequences, but with a preference for noncoding regions. This mutagenesis system also worked at least in B. longum NCC2705. Characterization of a transposon insertion mutant revealed that a putative α-glucosidase mediates palatinose and trehalose assimilation, demonstrating the suitability of transposon mutagenesis for loss-of-function analysis. We anticipate that this approach will accelerate functional genomic studies of B. longum subsp. longumIMPORTANCE Several hundred species of bacteria colonize the mammalian intestine. However, the genes that enable such bacteria to colonize and thrive in the intestine remain largely unexplored. Transposon mutagenesis, combined with next-generation sequencing, is a promising tool to comprehensively identify these genes but has so far been applied only to a small number of intestinal bacterial species. In this study, a transposon mutagenesis system was established for Bifidobacterium longum subsp. longum, a representative health-promoting Bifidobacterium species. The system enables the identification of genes that promote colonization and survival in the intestine and should help illuminate the physiology of this species.
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18
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Bottacini F, Zomer A, Milani C, Ferrario C, Lugli GA, Egan M, Ventura M, van Sinderen D. Global transcriptional landscape and promoter mapping of the gut commensal Bifidobacterium breve UCC2003. BMC Genomics 2017; 18:991. [PMID: 29281966 PMCID: PMC5746004 DOI: 10.1186/s12864-017-4387-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/15/2017] [Indexed: 12/16/2022] Open
Abstract
Background Bifidobacterium breve represents a common member of the infant gut microbiota and its presence in the gut has been associated with host well being. For this reason it is relevant to investigate and understand the molecular mechanisms underlying the establishment, persistence and activities of this gut commensal in the host environment. Results The assessment of vegetative promoters in the bifidobacterial prototype Bifidobacterium breve UCC2003 was performed employing a combination of RNA tiling array analysis and cDNA sequencing. Canonical −10 (TATAAT) and −35 (TTGACA) sequences were identified upstream of transcribed genes or operons, where deviations from this consensus correspond to transcription level variations. A Random Forest analysis assigned the −10 region of B. breve promoters as the element most impacting on the level of transcription, followed by the spacer length and the 5’-UTR length of transcripts. Furthermore, our transcriptome study also identified rho-independent termination as the most common and effective termination signal of highly and moderately transcribed operons in B. breve. Conclusion The present study allowed us to identify genes and operons that are actively transcribed in this organism during logarithmic growth, and link promoter elements with levels of transcription of essential genes in this organism. As homologs of many of our identified genes are present across the whole genus Bifidobacterium, our dataset constitutes a transcriptomic reference to be used for future investigations of gene expression in members of this genus. Electronic supplementary material The online version of this article (10.1186/s12864-017-4387-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Francesca Bottacini
- APC Microbiome Institute and School of Microbiology, University College Cork, Cork, Ireland
| | - Aldert Zomer
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Christian Milani
- Laboratory of Probiogenomics, Department of Chemical Sciences, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Chiara Ferrario
- Laboratory of Probiogenomics, Department of Chemical Sciences, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Gabriele Andrea Lugli
- Laboratory of Probiogenomics, Department of Chemical Sciences, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Muireann Egan
- APC Microbiome Institute and School of Microbiology, University College Cork, Cork, Ireland
| | - Marco Ventura
- Laboratory of Probiogenomics, Department of Chemical Sciences, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Douwe van Sinderen
- APC Microbiome Institute and School of Microbiology, University College Cork, Cork, Ireland.
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19
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Omics of bifidobacteria: research and insights into their health-promoting activities. Biochem J 2017; 474:4137-4152. [PMID: 29212851 DOI: 10.1042/bcj20160756] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 10/10/2017] [Accepted: 11/06/2017] [Indexed: 12/17/2022]
Abstract
Members of the genus Bifidobacterium include gut commensals that are particularly abundant among the microbial communities residing in the gut of healthy breast-fed infants, where their presence has been linked to many beneficial host effects. Next-generation DNA sequencing and comparative and functional genome methodologies have been shown to be particularly useful in exploring the diversity of this genus. These combined approaches have allowed the identification of genetic features related to bifidobacterial establishment in the gut, involving host-microbe as well as microbe-microbe interactions. Among these, proteinaceous structures, which protrude from the bacterial surface, i.e. pili or fimbriae, and exopolysaccharidic cell surface layers or capsules represent crucial features that assist in their colonization and persistence in the gut. As bifidobacteria are colonizers of the large intestine, they have to be able to cope with various sources of osmotic, oxidative, bile and acid stress during their transit across the gastric barrier and the small intestine. Bifidobacterial genomes thus encode various survival mechanisms, such as molecular chaperones and efflux pumps, to overcome such challenges. Bifidobacteria represent part of an anaerobic gut community, and feed on nondigestible carbohydrates through a specialized fermentative metabolic pathway, which in turn produces growth substrates for other members of the gut community. Conversely, bifidobacteria may also be dependent on other (bifido)bacteria to access host- and diet-derived glycans, and these complex co-operative interactions, based on resource sharing and cross-feeding strategies, represent powerful driving forces that shape gut microbiota composition.
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20
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Novel Genes Required for the Fitness of Streptococcus pyogenes in Human Saliva. mSphere 2017; 2:mSphere00460-17. [PMID: 29104937 PMCID: PMC5663985 DOI: 10.1128/mspheredirect.00460-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 10/09/2017] [Indexed: 12/29/2022] Open
Abstract
Streptococcus pyogenes (group A streptococcus [GAS]) causes 600 million cases of pharyngitis each year. Despite this considerable disease burden, the molecular mechanisms used by GAS to infect, cause clinical pharyngitis, and persist in the human oropharynx are poorly understood. Saliva is ubiquitous in the human oropharynx and is the first material GAS encounters in the upper respiratory tract. Thus, a fuller understanding of how GAS survives and proliferates in saliva may provide valuable insights into the molecular mechanisms at work in the human oropharynx. We generated a highly saturated transposon insertion mutant library in serotype M1 strain MGAS2221, a strain genetically representative of a pandemic clone that arose in the 1980s and spread globally. The transposon mutant library was exposed to human saliva to screen for GAS genes required for wild-type fitness in this clinically relevant fluid. Using transposon-directed insertion site sequencing (TraDIS), we identified 92 genes required for GAS fitness in saliva. The more prevalent categories represented were genes involved in carbohydrate transport/metabolism, amino acid transport/metabolism, and inorganic ion transport/metabolism. Using six isogenic mutant strains, we confirmed that each of the mutants was significantly impaired for growth or persistence in human saliva ex vivo. Mutants with an inactivated Spy0644 (sptA) or Spy0646 (sptC) gene had especially severe persistence defects. This study is the first to use of TraDIS to study bacterial fitness in human saliva. The new information we obtained will be valuable for future translational maneuvers designed to prevent or treat human GAS infections. IMPORTANCE The human bacterial pathogen Streptococcus pyogenes (group A streptococcus [GAS]) causes more than 600 million cases of pharyngitis annually worldwide, 15 million of which occur in the United States. The human oropharynx is the primary anatomic site for GAS colonization and infection, and saliva is the first material encountered. Using a genome-wide transposon mutant screen, we identified 92 GAS genes required for wild-type fitness in human saliva. Many of the identified genes are involved in carbohydrate transport/metabolism, amino acid transport/metabolism, and inorganic ion transport/metabolism. The new information is potentially valuable for developing novel GAS therapeutics and vaccine research.
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