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Basu A, Adams AN, Degnan PH, Vanderpool CK. Determinants of raffinose family oligosaccharide use in Bacteroides species. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.07.597959. [PMID: 38895307 PMCID: PMC11185731 DOI: 10.1101/2024.06.07.597959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Bacteroides species are successful colonizers of the human gut and can utilize a wide variety of complex polysaccharides and oligosaccharides that are indigestible by the host. To do this, they use enzymes encoded in Polysaccharide Utilization Loci (PULs). While recent work has uncovered the PULs required for use of some polysaccharides, how Bacteroides utilize smaller oligosaccharides is less well studied. Raffinose family oligosaccharides (RFOs) are abundant in plants, especially legumes, and consist of variable units of galactose linked by α-1,6 bonds to a sucrose (glucose α-1-β-2 fructose) moiety. Previous work showed that an α-galactosidase, BT1871, is required for RFO utilization in Bacteroides thetaiotaomicron. Here, we identify two different types of mutations that increase BT1871 mRNA levels and improve B. thetaiotaomicron growth on RFOs. First, a novel spontaneous duplication of BT1872 and BT1871 places these genes under control of a ribosomal promoter, driving high BT1871 transcription. Second, nonsense mutations in a gene encoding the PUL24 anti-sigma factor likewise increase BT1871 transcription. We then show that hydrolases from PUL22 work together with BT1871 to break down the sucrose moiety of RFOs and determine that the master regulator of carbohydrate utilization (BT4338) plays a role in RFO utilization in B. thetaiotaomicron. Examining the genomes of other Bacteroides species, we found homologs of BT1871 in subset and show that representative strains of species containing a BT1871 homolog grew better on melibiose than species that lack a BT1871 homolog. Altogether, our findings shed light on how an important gut commensal utilizes an abundant dietary oligosaccharide.
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Affiliation(s)
- Anubhav Basu
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Amanda N.D. Adams
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Patrick H. Degnan
- Department of Microbiology and Plant Pathology, University of California Riverside, Riverside, California, USA
| | - Carin K. Vanderpool
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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2
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Ryan D, Bornet E, Prezza G, Alampalli SV, Franco de Carvalho T, Felchle H, Ebbecke T, Hayward RJ, Deutschbauer AM, Barquist L, Westermann AJ. An expanded transcriptome atlas for Bacteroides thetaiotaomicron reveals a small RNA that modulates tetracycline sensitivity. Nat Microbiol 2024; 9:1130-1144. [PMID: 38528147 PMCID: PMC10994844 DOI: 10.1038/s41564-024-01642-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 02/07/2024] [Indexed: 03/27/2024]
Abstract
Plasticity in gene expression allows bacteria to adapt to diverse environments. This is particularly relevant in the dynamic niche of the human intestinal tract; however, transcriptional networks remain largely unknown for gut-resident bacteria. Here we apply differential RNA sequencing (RNA-seq) and conventional RNA-seq to the model gut bacterium Bacteroides thetaiotaomicron to map transcriptional units and profile their expression levels across 15 in vivo-relevant growth conditions. We infer stress- and carbon source-specific transcriptional regulons and expand the annotation of small RNAs (sRNAs). Integrating this expression atlas with published transposon mutant fitness data, we predict conditionally important sRNAs. These include MasB, which downregulates tetracycline tolerance. Using MS2 affinity purification and RNA-seq, we identify a putative MasB target and assess its role in the context of the MasB-associated phenotype. These data-publicly available through the Theta-Base web browser ( http://micromix.helmholtz-hiri.de/bacteroides/ )-constitute a valuable resource for the microbiome community.
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Affiliation(s)
- Daniel Ryan
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Elise Bornet
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Gianluca Prezza
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Shuba Varshini Alampalli
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Taís Franco de Carvalho
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Hannah Felchle
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
- Department of Radiation Oncology, Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Munich, Germany
| | - Titus Ebbecke
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Regan J Hayward
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Adam M Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
- Faculty of Medicine, University of Würzburg, Würzburg, Germany
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Alexander J Westermann
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany.
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany.
- Department of Microbiology, Biocentre, University of Würzburg, Würzburg, Germany.
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Kim TH, Ju K, Kim SK, Woo SG, Lee JS, Lee CH, Rha E, Shin J, Kwon KK, Lee H, Kim H, Lee SG, Lee DH. Novel Signal Peptides and Episomal Plasmid System for Enhanced Protein Secretion in Engineered Bacteroides Species. ACS Synth Biol 2024; 13:648-657. [PMID: 38224571 DOI: 10.1021/acssynbio.3c00649] [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] [Indexed: 01/17/2024]
Abstract
The genus Bacteroides, a predominant group in the human gut microbiome, presents significant potential for microbiome engineering and the development of live biotherapeutics aimed at treating gut diseases. Despite its promising capabilities, tools for effectively engineering Bacteroides species have been limited. In our study, we have made a breakthrough by identifying novel signal peptides in Bacteroides thetaiotaomicron and Akkermansia muciniphila. These peptides facilitate efficient protein transport across cellular membranes in Bacteroides, a critical step for therapeutic applications. Additionally, we have developed an advanced episomal plasmid system. This system demonstrates superior protein secretion capabilities compared to traditional chromosomal integration plasmids, making it a vital tool for enhancing the delivery of therapeutic proteins in Bacteroides species. Initially, the stability of this episomal plasmid posed a challenge; however, we have overcome this by incorporating an essential gene-based selection system. This novel strategy not only ensures plasmid stability but also aligns with the growing need for antibiotic-free selection methods in clinical settings. Our work, therefore, not only provides a more robust secretion system for Bacteroides but also sets a new standard for the development of live biotherapeutics.
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Affiliation(s)
- Tae Hyun Kim
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Kowoon Ju
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Seong Keun Kim
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Seung-Gyun Woo
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Jung-Sook Lee
- Korean Collection for Type Cultures, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Jeongeup-si 56212, Republic of Korea
| | - Chul-Ho Lee
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Eugene Rha
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Jonghyeok Shin
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Kil Koang Kwon
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Hyewon Lee
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Haseong Kim
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
- Graduate School of Engineering Biology, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Seung-Goo Lee
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
- Graduate School of Engineering Biology, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Dae-Hee Lee
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
- Graduate School of Engineering Biology, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
- Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
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Prezza G, Liao C, Reichardt S, Beisel CL, Westermann AJ. CRISPR-based screening of small RNA modulators of bile susceptibility in Bacteroides thetaiotaomicron. Proc Natl Acad Sci U S A 2024; 121:e2311323121. [PMID: 38294941 PMCID: PMC10861873 DOI: 10.1073/pnas.2311323121] [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: 07/12/2023] [Accepted: 12/12/2023] [Indexed: 02/02/2024] Open
Abstract
Microbiota-centric interventions are limited by our incomplete understanding of the gene functions of many of its constituent species. This applies in particular to small RNAs (sRNAs), which are emerging as important regulators in microbiota species yet tend to be missed by traditional functional genomics approaches. Here, we establish CRISPR interference (CRISPRi) in the abundant microbiota member Bacteroides thetaiotaomicron for genome-wide sRNA screens. By assessing the abundance of different protospacer-adjacent motifs, we identify the Prevotella bryantii B14 Cas12a as a suitable nuclease for CRISPR screens in these bacteria and generate an inducible Cas12a expression system. Using a luciferase reporter strain, we infer guide design rules and use this knowledge to assemble a computational pipeline for automated gRNA design. By subjecting the resulting guide library to a phenotypic screen, we uncover the sRNA BatR to increase susceptibility to bile salts through the regulation of genes involved in Bacteroides cell surface structure. Our study lays the groundwork for unlocking the genetic potential of these major human gut mutualists and, more generally, for identifying hidden functions of bacterial sRNAs.
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Affiliation(s)
- Gianluca Prezza
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, WürzburgD-97080, Germany
| | - Chunyu Liao
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, WürzburgD-97080, Germany
| | - Sarah Reichardt
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, WürzburgD-97080, Germany
| | - Chase L. Beisel
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, WürzburgD-97080, Germany
- Medical Faculty, University of Würzburg, WürzburgD-97080, Germany
| | - Alexander J. Westermann
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, WürzburgD-97080, Germany
- Institute of Molecular Infection Biology, University of Würzburg, WürzburgD-97080, Germany
- Department of Microbiology, Biocentre, University of Würzburg, WürzburgD-97074, Germany
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5
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Prezza G, Westermann AJ. CRISPR Interference-Based Functional Small RNA Genomics. Methods Mol Biol 2024; 2741:101-116. [PMID: 38217650 DOI: 10.1007/978-1-0716-3565-0_6] [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] [Indexed: 01/15/2024]
Abstract
Small RNAs (sRNAs) are versatile regulators universally present in species across the prokaryotic kingdom, yet their functional characterization remains a major bottleneck. Gene inactivation through random transposon insertion has proven extremely valuable in discovering hidden gene functions. However, this approach is biased toward long genes and usually results in the underrepresentation of sRNA mutants. In contrast, CRISPR interference (CRISPRi) harnesses guide RNAs to recruit cleavage-deficient Cas nucleases to specific DNA loci. The ensuing steric hindrance inhibits RNA polymerase assembly at-or migration along-predefined genes, allowing for targeted knockdown screens without major length bias. In this chapter, we provide a detailed protocol for CRISPRi-based functional screening of bacterial sRNAs. Using the abundant microbiota species Bacteroides thetaiotaomicron as a model, we describe the design and generation of a guide library targeting the full intergenic sRNA repertoire of this organism and its application to identify sRNA knockdown-associated fitness effects. Our protocol is generic and thus suitable for the systematic assessment of sRNA-associated phenotypes in a wide range of bacterial species and experimental conditions. We expect CRISPRi-based functional genomics to boost sRNA research in understudied bacterial taxa, for instance, members of the gut microbiota.
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Affiliation(s)
- Gianluca Prezza
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Alexander J Westermann
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany.
- Institute of Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany.
- Department of Microbiology, Biocentre, University of Würzburg, Würzburg, Germany.
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6
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Liu S, Wang Z, Wang Z, Wu Q, Zhou J, Wang R, Han J, Su X. Comparison of the gut microbiota and metabolism in different regions of Red Swamp Crayfish ( Procambarus clarkii). Front Microbiol 2023; 14:1289634. [PMID: 38188569 PMCID: PMC10770849 DOI: 10.3389/fmicb.2023.1289634] [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: 09/07/2023] [Accepted: 11/27/2023] [Indexed: 01/09/2024] Open
Abstract
Background The gut microbiota is very important for maintaining the homeostasis and health of crustaceans. Many factors affect the gut microbiota of crustaceans, one of which is temperature. However, it is currently unclear how temperature affects the gut microbiota and metabolites of Procambarus clarkii. Methods Using metagenomic sequencing and gas chromatography-mass spectrometry (GC-MS) techniques, the gut microbiota and metabolites of P. clarkii from Hubei (HB), Jiangsu (JS), Shandong (SD), and Zhejiang (ZJ) in China were investigated. Results Under the impact of temperature, the gut microbiota and metabolites of P. clarkii exhibit a specific trend of change. The primary pathogenic bacteria affecting P. clarkii are Citrobacter, Enterobacterium, and Aeromonas, which are affected by temperature. Two metabolites, namely, sugars and amino acids, are regulated by temperature. Implication This study demonstrated that the gut microbiota and gut metabolites of P. clarkii were considerably affected by temperature. It provides a theoretical basis for the systematic study of P. clarkii and provides a basis for a healthy culture of P. clarkii.
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Affiliation(s)
- Songyi Liu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, China
- School of Marine Science, Ningbo University, Ningbo, China
| | - Ziyan Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, China
- School of Marine Science, Ningbo University, Ningbo, China
| | - Ze Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, China
- School of Marine Science, Ningbo University, Ningbo, China
| | - Qiaoli Wu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, China
- School of Marine Science, Ningbo University, Ningbo, China
| | - Jun Zhou
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, China
- School of Marine Science, Ningbo University, Ningbo, China
| | - Rixin Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, China
- School of Marine Science, Ningbo University, Ningbo, China
| | - Jiaojiao Han
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, China
- School of Marine Science, Ningbo University, Ningbo, China
| | - Xiurong Su
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, China
- School of Marine Science, Ningbo University, Ningbo, China
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7
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Kim K, Kang M, Cho BK. Systems and synthetic biology-driven engineering of live bacterial therapeutics. Front Bioeng Biotechnol 2023; 11:1267378. [PMID: 37929193 PMCID: PMC10620806 DOI: 10.3389/fbioe.2023.1267378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 10/09/2023] [Indexed: 11/07/2023] Open
Abstract
The past decade has seen growing interest in bacterial engineering for therapeutically relevant applications. While early efforts focused on repurposing genetically tractable model strains, such as Escherichia coli, engineering gut commensals is gaining traction owing to their innate capacity to survive and stably propagate in the intestine for an extended duration. Although limited genetic tractability has been a major roadblock, recent advances in systems and synthetic biology have unlocked our ability to effectively harness native gut commensals for therapeutic and diagnostic purposes, ranging from the rational design of synthetic microbial consortia to the construction of synthetic cells that execute "sense-and-respond" logic operations that allow real-time detection and therapeutic payload delivery in response to specific signals in the intestine. In this review, we outline the current progress and latest updates on microbial therapeutics, with particular emphasis on gut commensal engineering driven by synthetic biology and systems understanding of their molecular phenotypes. Finally, the challenges and prospects of engineering gut commensals for therapeutic applications are discussed.
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Affiliation(s)
- Kangsan Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
- KAIST Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Minjeong Kang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
- KAIST Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Byung-Kwan Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
- KAIST Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
- Graduate School of Engineering Biology, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
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Abstract
Small regulatory RNA (sRNAs) are key mediators of posttranscriptional gene control in bacteria. Assisted by RNA-binding proteins, a single sRNA often modulates the expression of dozens of genes, and thus sRNAs frequently adopt central roles in regulatory networks. Posttranscriptional regulation by sRNAs comes with several unique features that cannot be achieved by transcriptional regulators. However, for optimal network performance, transcriptional and posttranscriptional control mechanisms typically go hand-in-hand. This view is reflected by the ever-growing class of mixed network motifs involving sRNAs and transcription factors, which are ubiquitous in biology and whose regulatory properties we are beginning to understand. In addition, sRNA activity can be antagonized by base-pairing with sponge RNAs, adding yet another layer of complexity to these networks. In this article, we summarize the regulatory concepts underlying sRNA-mediated gene control in bacteria and discuss how sRNAs shape the output of a network, focusing on several key examples.
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Affiliation(s)
- Kai Papenfort
- Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany;
- Microverse Cluster, Friedrich Schiller University Jena, Jena, Germany
| | - Sahar Melamed
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel;
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Cai Y, Si Z, Jiang Y, Ye M, Wang F, Yang X, Yu J, Gao X, Liu W. Structure-activity relationship of low molecular weight Astragalus membranaceus polysaccharides produced by Bacteroides. Carbohydr Polym 2023; 316:121036. [PMID: 37321731 DOI: 10.1016/j.carbpol.2023.121036] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 05/10/2023] [Accepted: 05/16/2023] [Indexed: 06/17/2023]
Abstract
Astragalus membranaceus polysaccharides (APS) possess significant biological activities, such as anti-tumor, antiviral, and immunomodulatory activities. However, there is still a lack of research on the structure-activity relationship of APS. In this paper, two carbohydrate-active enzymes from Bacteroides in living organisms were used to prepare degradation products. The degradation products were divided into APS-A1, APS-G1, APS-G2, and APS-G3 according to molecular weight. Structural analysis showed that all degradation products had an α-1,4-linked glucose backbone, but APS-A1 and APS-G3 also had branched chains of α-1,6-linked galactose or arabinogalacto-oligosaccharide. In vitro, immunomodulatory activity evaluation results indicated that APS-A1 and APS-G3 had better immunomodulatory activity, while the immunomodulatory activities of APS-G1 and APS-G2 were comparatively weaker. Molecular interaction detection showed that APS-A1 and APS-G3 could bind to toll-like receptors-4 (TLR-4) with a binding constant of 4.6 × 10-5 and 9.4 × 10-6, respectively, while APS-G1 and APS-G2 failed to bind to TLR-4. Therefore, the branched chains of galactose or arabinogalacto-oligosaccharide played a crucial role in the immunomodulatory activity of APS.
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Affiliation(s)
- Yang Cai
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, College of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
| | - Zhenyuan Si
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, College of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
| | - Ying Jiang
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, College of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
| | - Meng Ye
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, College of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
| | - Feng Wang
- Simcere Pharmaceutical Group Limited, Nanjing 210042, PR China
| | - Xiaobing Yang
- Biology and Medicine Department, Jiangsu Industrial Technology Research Institute, Nanjing 210031, PR China
| | - Juping Yu
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, College of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China.
| | - Xiangdong Gao
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, College of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China.
| | - Wei Liu
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, College of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China.
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10
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Ferrara S, Brignoli T, Bertoni G. Little reason to call them small noncoding RNAs. Front Microbiol 2023; 14:1191166. [PMID: 37455713 PMCID: PMC10339803 DOI: 10.3389/fmicb.2023.1191166] [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: 03/21/2023] [Accepted: 06/14/2023] [Indexed: 07/18/2023] Open
Abstract
Hundreds of different species of small RNAs can populate a bacterial cell. This small transcriptome contains important information for the adaptation of cellular physiology to environmental changes. Underlying cellular networks involving small RNAs are RNA-RNA and RNA-protein interactions, which are often intertwined. In addition, small RNAs can function as mRNAs. In general, small RNAs are referred to as noncoding because very few are known to contain translated open reading frames. In this article, we intend to highlight that the number of small RNAs that fall within the set of translated RNAs is bound to increase. In addition, we aim to emphasize that the dynamics of the small transcriptome involve different functional codes, not just the genetic code. Therefore, since the role of small RNAs is always code-driven, we believe that there is little reason to continue calling them small noncoding RNAs.
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Tawk C, Lim B, Bencivenga-Barry NA, Lees HJ, Ramos RJF, Cross J, Goodman AL. Infection leaves a genetic and functional mark on the gut population of a commensal bacterium. Cell Host Microbe 2023; 31:811-826.e6. [PMID: 37119822 PMCID: PMC10197903 DOI: 10.1016/j.chom.2023.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 03/04/2023] [Accepted: 04/04/2023] [Indexed: 05/01/2023]
Abstract
Gastrointestinal infection changes microbiome composition and gene expression. In this study, we demonstrate that enteric infection also promotes rapid genetic adaptation in a gut commensal. Measurements of Bacteroides thetaiotaomicron population dynamics within gnotobiotic mice reveal that these populations are relatively stable in the absence of infection, and the introduction of the enteropathogen Citrobacter rodentium reproducibly promotes rapid selection for a single-nucleotide variant with increased fitness. This mutation promotes resistance to oxidative stress by altering the sequence of a protein, IctA, that is essential for fitness during infection. We identified commensals from multiple phyla that attenuate the selection of this variant during infection. These species increase the levels of vitamin B6 in the gut lumen. Direct administration of this vitamin is sufficient to significantly reduce variant expansion in infected mice. Our work demonstrates that a self-limited enteric infection can leave a stable mark on resident commensal populations that increase fitness during infection.
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Affiliation(s)
- Caroline Tawk
- Department of Microbial Pathogenesis and Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Bentley Lim
- Department of Microbial Pathogenesis and Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Natasha A Bencivenga-Barry
- Department of Microbial Pathogenesis and Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Hannah J Lees
- The Donald B. and Catherine C. Marron Cancer Metabolism Center, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Ruben J F Ramos
- The Donald B. and Catherine C. Marron Cancer Metabolism Center, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Justin Cross
- The Donald B. and Catherine C. Marron Cancer Metabolism Center, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Andrew L Goodman
- Department of Microbial Pathogenesis and Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT 06510, USA.
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12
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Ryan D, Bornet E, Prezza G, Alampalli SV, de Carvalho TF, Felchle H, Ebbecke T, Hayward R, Deutschbauer AM, Barquist L, Westermann AJ. An integrated transcriptomics-functional genomics approach reveals a small RNA that modulates Bacteroides thetaiotaomicron sensitivity to tetracyclines. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.16.528795. [PMID: 36824877 PMCID: PMC9949090 DOI: 10.1101/2023.02.16.528795] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Gene expression plasticity allows bacteria to adapt to diverse environments, tie their metabolism to available nutrients, and cope with stress. This is particularly relevant in a niche as dynamic and hostile as the human intestinal tract, yet transcriptional networks remain largely unknown in gut Bacteroides spp. Here, we map transcriptional units and profile their expression levels in Bacteroides thetaiotaomicron over a suite of 15 defined experimental conditions that are relevant in vivo , such as variation of temperature, pH, and oxygen tension, exposure to antibiotic stress, and growth on simple carbohydrates or on host mucin-derived glycans. Thereby, we infer stress- and carbon source-specific transcriptional regulons, including conditional expression of capsular polysaccharides and polysaccharide utilization loci, and expand the annotation of small regulatory RNAs (sRNAs) in this organism. Integrating this comprehensive expression atlas with transposon mutant fitness data, we identify conditionally important sRNAs. One example is MasB, whose inactivation led to increased bacterial tolerance of tetracyclines. Using MS2 affinity purification coupled with RNA sequencing, we predict targets of this sRNA and discuss their potential role in the context of the MasB-associated phenotype. Together, this transcriptomic compendium in combination with functional sRNA genomics-publicly available through a new iteration of the 'Theta-Base' web browser (www.helmholtz-hiri.de/en/datasets/bacteroides-v2)-constitutes a valuable resource for the microbiome and sRNA research communities alike.
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13
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Kavita K, Breaker RR. Discovering riboswitches: the past and the future. Trends Biochem Sci 2023; 48:119-141. [PMID: 36150954 PMCID: PMC10043782 DOI: 10.1016/j.tibs.2022.08.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 08/18/2022] [Accepted: 08/26/2022] [Indexed: 01/25/2023]
Abstract
Riboswitches are structured noncoding RNA domains used by many bacteria to monitor the concentrations of target ligands and regulate gene expression accordingly. In the past 20 years over 55 distinct classes of natural riboswitches have been discovered that selectively sense small molecules or elemental ions, and thousands more are predicted to exist. Evidence suggests that some riboswitches might be direct descendants of the RNA-based sensors and switches that were likely present in ancient organisms before the evolutionary emergence of proteins. We provide an overview of the current state of riboswitch research, focusing primarily on the discovery of riboswitches, and speculate on the major challenges facing researchers in the field.
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Affiliation(s)
- Kumari Kavita
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA
| | - Ronald R Breaker
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520-8103, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8103, USA.
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14
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Pearce VH, Groisman EA, Townsend GE. Dietary sugars silence the master regulator of carbohydrate utilization in human gut Bacteroides species. Gut Microbes 2023; 15:2221484. [PMID: 37358144 PMCID: PMC10294740 DOI: 10.1080/19490976.2023.2221484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 05/08/2023] [Indexed: 06/27/2023] Open
Abstract
The mammalian gut microbiota is a critical human health determinant with therapeutic potential for remediation of many diseases. The host diet is a key factor governing the gut microbiota composition by altering nutrient availability and supporting the expansion of distinct microbial populations. Diets rich in simple sugars modify the abundance of microbial subsets, enriching for microbiotas that elicit pathogenic outcomes. We previously demonstrated that diets rich in fructose and glucose can reduce the fitness and abundance of a human gut symbiont, Bacteroides thetaiotaomicron, by silencing the production of a critical intestinal colonization protein, called Roc, via its mRNA leader through an unknown mechanism. We have now determined that dietary sugars silence Roc by reducing the activity of BT4338, a master regulator of carbohydrate utilization. Here, we demonstrate that BT4338 is required for Roc synthesis, and that BT4338 activity is silenced by glucose or fructose. We show that the consequences of glucose and fructose on orthologous transcription factors are conserved across human intestinal Bacteroides species. This work identifies a molecular pathway by which a common dietary additive alters microbial gene expression in the gut that could be harnessed to modulate targeted microbial populations for future therapeutic interventions.
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Affiliation(s)
- Victoria H. Pearce
- Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, PA, USA
- Penn State Microbiome Center, Pennsylvania State University, State College, PA, USA
- Center for Molecular Carcinogenesis and Toxicology, Pennsylvania State University, State College, PA, USA
| | - Eduardo A. Groisman
- Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
- Microbial Sciences Institute, Yale University, New Haven, CT, USA
| | - Guy E. Townsend
- Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, PA, USA
- Penn State Microbiome Center, Pennsylvania State University, State College, PA, USA
- Center for Molecular Carcinogenesis and Toxicology, Pennsylvania State University, State College, PA, USA
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15
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Wei G, Li S, Ye S, Wang Z, Zarringhalam K, He J, Wang W, Shao Z. High-Resolution Small RNAs Landscape Provides Insights into Alkane Adaptation in the Marine Alkane-Degrader Alcanivorax dieselolei B-5. Int J Mol Sci 2022; 23:ijms232415995. [PMID: 36555635 PMCID: PMC9788540 DOI: 10.3390/ijms232415995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/07/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022] Open
Abstract
Alkanes are widespread in the ocean, and Alcanivorax is one of the most ubiquitous alkane-degrading bacteria in the marine ecosystem. Small RNAs (sRNAs) are usually at the heart of regulatory pathways, but sRNA-mediated alkane metabolic adaptability still remains largely unknown due to the difficulties of identification. Here, differential RNA sequencing (dRNA-seq) modified with a size selection (~50-nt to 500-nt) strategy was used to generate high-resolution sRNAs profiling in the model species Alcanivorax dieselolei B-5 under alkane (n-hexadecane) and non-alkane (acetate) conditions. As a result, we identified 549 sRNA candidates at single-nucleotide resolution of 5'-ends, 63.4% of which are with transcription start sites (TSSs), and 36.6% of which are with processing sites (PSSs) at the 5'-ends. These sRNAs originate from almost any location in the genome, regardless of intragenic (65.8%), antisense (20.6%) and intergenic (6.2%) regions, and RNase E may function in the maturation of sRNAs. Most sRNAs locally distribute across the 15 reference genomes of Alcanivorax, and only 7.5% of sRNAs are broadly conserved in this genus. Expression responses to the alkane of several core conserved sRNAs, including 6S RNA, M1 RNA and tmRNA, indicate that they may participate in alkane metabolisms and result in more actively global transcription, RNA processing and stresses mitigation. Two novel CsrA-related sRNAs are identified, which may be involved in the translational activation of alkane metabolism-related genes by sequestering the global repressor CsrA. The relationships of sRNAs with the characterized genes of alkane sensing (ompS), chemotaxis (mcp, cheR, cheW2), transporting (ompT1, ompT2, ompT3) and hydroxylation (alkB1, alkB2, almA) were created based on the genome-wide predicted sRNA-mRNA interactions. Overall, the sRNA landscape lays the ground for uncovering cryptic regulations in critical marine bacterium, among which both the core and species-specific sRNAs are implicated in the alkane adaptive metabolisms.
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Affiliation(s)
- Guangshan Wei
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai 519082, China
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Fujian Province, Xiamen 361005, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China
| | - Sujie Li
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Fujian Province, Xiamen 361005, China
| | - Sida Ye
- Department of Mathematics, University of Massachusetts Boston, Boston, MA 02125, USA
- Center for Personalized Cancer Therapy, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Zining Wang
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Fujian Province, Xiamen 361005, China
| | - Kourosh Zarringhalam
- Department of Mathematics, University of Massachusetts Boston, Boston, MA 02125, USA
- Center for Personalized Cancer Therapy, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Jianguo He
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China
| | - Wanpeng Wang
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Fujian Province, Xiamen 361005, China
- Correspondence: (W.W.); (Z.S.)
| | - Zongze Shao
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai 519082, China
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China
- State Key Laboratory Breeding Base of Marine Genetic Resources, Key Laboratory of Marine Genetic Resources of Fujian Province, Xiamen 361005, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China
- Correspondence: (W.W.); (Z.S.)
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16
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Overall Structural Alteration of Gut Microbiota and Relationships with Risk Factors in Patients with Metabolic Syndrome Treated with Inulin Alone and with Other Agents: An Open-Label Pilot Study. Mediators Inflamm 2022; 2022:2078520. [PMID: 35633654 PMCID: PMC9136633 DOI: 10.1155/2022/2078520] [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: 01/24/2022] [Revised: 04/26/2022] [Accepted: 05/05/2022] [Indexed: 11/21/2022] Open
Abstract
Objective The relative contribution of some products with prebiotic effects, such as inulin, together with medications specific to the human gut microbiome has not been comprehensively studied. The present study determined the potential for manipulating populations in the gut microbiome using inulin alone and combined with other agents in individuals with metabolic syndrome (MetS). The study also assessed whether there is relationship variability in multiple clinical parameters in response to intervention with the changes in the gut milieu. Participants/Methods. This single-centre, single-blinded, randomised community-based pilot trial randomly assigned 60 patients (mean age, 46.3 y and male, 43%) with MetS to receive either inulin, inulin+traditional Chinese medicine (TCM), or inulin+metformin for 6 months. Lipid profiles, blood glucose, and uric acid (UA) levels were analysed in venous blood samples collected after overnight fast of 8 h at baseline and at the end of the follow-up period. Microbiota from stool samples were taxonomically analysed using 16S RNA amplicon sequencing, and an integrative analysis was conducted on microbiome and responsiveness data at 6 months. Results The results of 16S rRNA sequencing showed that inulin resulted in a higher proportion of Bacteroides at the endpoint compared with inulin+TCM and inulin+metformin (p = 0.024). More Romboutsia (p = 0.043), Streptococcus (p < 0.001), and Holdemanella (p = 0.011) were found in inulin+TCM and inulin+metformin samples. We further identified gut microbiota relationships with lipids, UA, and glucose that impact the development of MetS. Conclusion Among the groups, inulin alone or combined with metformin or TCM altered specific gut microbiota taxa but not the general diversity. Accordingly, we analysed metabolites associated with microbiota that might provide more information about intrinsic differences. Consequently, a reliable method could be developed for treating metabolic syndrome in the future.
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17
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Heavey MK, Durmusoglu D, Crook N, Anselmo AC. Discovery and delivery strategies for engineered live biotherapeutic products. Trends Biotechnol 2022; 40:354-369. [PMID: 34481657 PMCID: PMC8831446 DOI: 10.1016/j.tibtech.2021.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 10/20/2022]
Abstract
Genetically engineered microbes that secrete therapeutics, sense and respond to external environments, and/or target specific sites in the gut fall under an emergent class of therapeutics, called live biotherapeutic products (LBPs). As live organisms that require symbiotic host interactions, LBPs offer unique therapeutic opportunities, but also face distinct challenges in the gut microenvironment. In this review, we describe recent approaches (often demonstrated using traditional probiotic microorganisms) to discover LBP chassis and genetic parts utilizing omics-based methods and highlight LBP delivery strategies, with a focus on addressing physiological challenges that LBPs encounter after oral administration. Finally, we share our perspective on the opportunity to apply an integrated approach, wherein discovery and delivery strategies are utilized synergistically, towards tailoring and optimizing LBP efficacy.
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Affiliation(s)
- Mairead K. Heavey
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Deniz Durmusoglu
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Nathan Crook
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA.
| | - Aaron C. Anselmo
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA,Correspondence: (A.C. Anselmo), (N. Crook)
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18
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Investigation and Alteration of Organic Acid Synthesis Pathways in the Mammalian Gut Symbiont Bacteroides thetaiotaomicron. Microbiol Spectr 2022; 10:e0231221. [PMID: 35196806 PMCID: PMC8865466 DOI: 10.1128/spectrum.02312-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Members of the gut-dwelling Bacteroides genus have remarkable abilities in degrading a diverse set of fiber polysaccharide structures, most of which are found in the mammalian diet. As part of their metabolism, they convert these fibers to organic acids that can in turn provide energy to their host. While many studies have identified and characterized the genes and corresponding proteins involved in polysaccharide degradation, relatively little is known about Bacteroides genes involved in downstream metabolic pathways. Bacteroides thetaiotaomicron is one of the most studied species from the genus and is representative of this group in producing multiple organic acids as part of its metabolism. We focused here on several organic acid synthesis pathways in B. thetaiotaomicron, including those involved in formate, lactate, propionate, and acetate production. We identified potential genes involved in each pathway and characterized these through gene deletions coupled to growth assays and organic acid quantification. In addition, we developed and employed a Golden Gate-compatible plasmid system to simplify alteration of native gene expression levels. Our work both validates and contradicts previous bioinformatic gene annotations, and we develop a model on which to base future efforts. A clearer understanding of Bacteroides metabolic pathways can inform and facilitate efforts to employ these bacteria for improved human health or other utilization strategies. IMPORTANCE Both humans and animals host a large community of bacteria and other microorganisms in their gastrointestinal tracts. This community breaks down dietary fiber and produces organic acids that are used as an energy source by the body and can also help the host resist infection by various pathogens. While the Bacteroides genus is one of the most common in the gut microbiota, it is only distantly related to bacteria with well-characterized metabolic pathways and it is therefore unclear whether research insights on organic acid production in those species can also be directly applied to the Bacteroides. By investigating multiple genetic pathways for organic acid production in Bacteroides thetaiotaomicron, we provide a basis for deeper understanding of these pathways. The work further enables greater understanding of Bacteroides–host relationships, as well as inter-species relationships in the microbiota, which are of importance for both human and animal gut health.
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19
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Shatoff EA, Gemler BT, Bundschuh R, Fredrick K. Maturation of 23S rRNA includes removal of helix H1 in many bacteria. RNA Biol 2021; 18:856-865. [PMID: 34812116 PMCID: PMC8782170 DOI: 10.1080/15476286.2021.2000793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In most bacteria, the three ribosomal RNAs (rRNAs) are encoded together in each of several near-identical operons. As soon as the nascent precursor rRNA emerges from RNA polymerase, ribosome assembly begins. This process entails ribosomal protein binding, rRNA folding, rRNA modification, and rRNA processing. In the model organisms Escherichia coli and Bacillus subtilis, rRNA processing results in similar mature rRNAs, despite substantial differences in the cohort of RNAses involved. A recent study of Flavobacterium johnsoniae, a member of the phylum Bacteroidota (formerly Bacteroidetes), revealed that helix H1 of 23S rRNA is absent from ribosomes, apparently a consequence of rRNA maturation. In this work, we mined RNA-seq data from 19 individual organisms and ocean metatranscriptomic samples to compare rRNA processing across diverse bacterial lineages. We found that mature ribosomes from multiple clades lack H1, and typically these ribosomes also lack an encoded H98. For all groups analysed, H1 is predicted to form in precursor rRNA as part of a longer leader-trailer helix. Hence, we infer that evolutionary loss of H98 sets the stage for H1 removal during 50S subunit maturation.
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Affiliation(s)
- Elan A Shatoff
- Department of Physics, The Ohio State University, Columbus, OH, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Bryan T Gemler
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA
| | - Ralf Bundschuh
- Department of Physics, The Ohio State University, Columbus, OH, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA.,Department of Chemistry & Biochemistry, The Ohio State University, Columbus, OH, USA.,Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH, USA
| | - Kurt Fredrick
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Microbiology, The Ohio State University, Columbus, OH, USA
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20
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Oogai Y, Nakata M. Small regulatory RNAs of oral streptococci and periodontal bacteria. JAPANESE DENTAL SCIENCE REVIEW 2021; 57:209-216. [PMID: 34745393 PMCID: PMC8551640 DOI: 10.1016/j.jdsr.2021.09.004] [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: 06/29/2021] [Revised: 09/20/2021] [Accepted: 09/24/2021] [Indexed: 11/27/2022] Open
Abstract
Small regulatory RNAs (sRNAs) belong to a family of non-coding RNAs, and many of which regulate expression of genes via interaction with mRNA. The recent popularity of high-throughput next generation sequencers have presented abundant sRNA-related data, including sRNAs of several different oral bacterial species. Some sRNA candidates have been validated in terms of their expression and interaction with target mRNAs. Since the oral cavity is an environment constantly exposed to various stimuli, such as fluctuations in temperature and pH, and osmotic pressure, as well as changes in nutrient availability, oral bacteria require rapid control of gene expression for adaptation to such diverse conditions, while regulation via interactions of sRNAs with mRNA provides advantages for rapid adaptation. This review summarizes methods effective for identification and validation of sRNAs, as well as sRNAs identified to be associated with oral bacterial species, including cariogenic and periodontal pathogens, together with their confirmed and putative target genes.
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Affiliation(s)
- Yuichi Oogai
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, 890-8544, Japan
| | - Masanobu Nakata
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, 890-8544, Japan
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21
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Identification of BvgA-Dependent and BvgA-Independent Small RNAs (sRNAs) in Bordetella pertussis Using the Prokaryotic sRNA Prediction Toolkit ANNOgesic. Microbiol Spectr 2021; 9:e0004421. [PMID: 34550019 PMCID: PMC8557813 DOI: 10.1128/spectrum.00044-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Noncoding small RNAs (sRNAs) are crucial for the posttranscriptional regulation of gene expression in all organisms and are known to be involved in the regulation of bacterial virulence. In the human pathogen Bordetella pertussis, which causes whooping cough, virulence is controlled primarily by the master two-component system BvgA (response regulator)/BvgS (sensor kinase). In this system, BvgA is phosphorylated (Bvg+ mode) or nonphosphorylated (Bvg- mode), with global transcriptional differences between the two. B. pertussis also carries the bacterial sRNA chaperone Hfq, which has previously been shown to be required for virulence. Here, we conducted transcriptomic analyses to identify possible B. pertussis sRNAs and to determine their BvgAS dependence using transcriptome sequencing (RNA-seq) and the prokaryotic sRNA prediction program ANNOgesic. We identified 143 possible candidates (25 Bvg+ mode specific and 53 Bvg- mode specific), of which 90 were previously unreported. Northern blot analyses confirmed all of the 10 ANNOgesic candidates that we tested. Homology searches demonstrated that 9 of the confirmed sRNAs are highly conserved among B. pertussis, Bordetella parapertussis, and Bordetella bronchiseptica, with one that also has homologues in other species of the Alcaligenaceae family. Using coimmunoprecipitation with a B. pertussis FLAG-tagged Hfq, we demonstrated that 3 of the sRNAs interact directly with Hfq, which is the first identification of sRNA binding to B. pertussis Hfq. Our study demonstrates that ANNOgesic is a highly useful tool for the identification of sRNAs in this system and that its combination with molecular techniques is a successful way to identify various BvgAS-dependent and Hfq-binding sRNAs. IMPORTANCE Noncoding small RNAs (sRNAs) are crucial for posttranscriptional regulation of gene expression in all organisms and are known to be involved in the regulation of bacterial virulence. We have investigated the presence of sRNAs in the obligate human pathogen B. pertussis, using transcriptome sequencing (RNA-seq) and the recently developed prokaryotic sRNA search program ANNOgesic. This analysis has identified 143 sRNA candidates (90 previously unreported). We have classified their dependence on the B. pertussis two-component system required for virulence, namely, BvgAS, based on their expression in the presence/absence of the phosphorylated response regulator BvgA, confirmed several by Northern analyses, and demonstrated that 3 bind directly to B. pertussis Hfq, the RNA chaperone involved in mediating sRNA effects. Our study demonstrates the utility of combining RNA-seq, ANNOgesic, and molecular techniques to identify various BvgAS-dependent and Hfq-binding sRNAs, which may unveil the roles of sRNAs in pertussis pathogenesis.
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22
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Adams AND, Azam MS, Costliow ZA, Ma X, Degnan PH, Vanderpool CK. A Novel Family of RNA-Binding Proteins Regulate Polysaccharide Metabolism in Bacteroides thetaiotaomicron. J Bacteriol 2021; 203:e0021721. [PMID: 34251866 PMCID: PMC8508124 DOI: 10.1128/jb.00217-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/08/2021] [Indexed: 11/20/2022] Open
Abstract
Human gut microbiome composition is constantly changing, and diet is a major driver of these changes. Gut microbial species that persist in mammalian hosts for long periods of time must possess mechanisms for sensing and adapting to nutrient shifts to avoid being outcompeted. Global regulatory mechanisms mediated by RNA-binding proteins (RBPs) that govern responses to nutrient shifts have been characterized in Proteobacteria and Firmicutes but remain undiscovered in the Bacteroidetes. Here, we report the identification of RBPs that are broadly distributed across the Bacteroidetes, with many genomes encoding multiple copies. Genes encoding these RBPs are highly expressed in many Bacteroides species. A purified RBP, RbpB, from Bacteroides thetaiotaomicron binds to single-stranded RNA in vitro with an affinity similar to other characterized regulatory RBPs. B. thetaiotaomicron mutants lacking RBPs show dramatic shifts in expression of polysaccharide utilization and capsular polysaccharide loci, suggesting that these RBPs may act as global regulators of polysaccharide metabolism. A B. thetaiotaomicron ΔrbpB mutant shows a growth defect on dietary sugars belonging to the raffinose family of oligosaccharides (RFOs). The ΔrbpB mutant had reduced expression of BT1871, encoding a predicted RFO-degrading melibiase, compared to the wild-type strain. Mutation of BT1871 confirmed that the enzyme it encodes is essential for growth on melibiose and promotes growth on the RFOs raffinose and stachyose. Our data reveal that RbpB is required for optimal expression of BT1871 and other polysaccharide-related genes, suggesting that we have identified an important new family of global regulatory proteins in the Bacteroidetes. IMPORTANCE The human colon houses hundreds of bacterial species, including many belonging to the genus Bacteroides, that aid in breaking down our food to keep us healthy. Bacteroides have many genes responsible for breaking down different dietary carbohydrates, and complex regulatory mechanisms ensure that specific genes are only expressed when the right carbohydrates are available. In this study, we discovered that Bacteroides use a family of RNA-binding proteins as global regulators to coordinate expression of carbohydrate utilization genes. The ability to turn different carbohydrate utilization genes on and off in response to changing nutrient conditions is critical for Bacteroides to live successfully in the gut, and thus the new regulators we have identified may be important for life in the host.
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Affiliation(s)
- Amanda N. D. Adams
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Muhammad S. Azam
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Zachary A. Costliow
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Xiangqian Ma
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Patrick H. Degnan
- Department of Microbiology and Plant Pathology, University of California-Riverside, Riverside, California, USA
| | - Carin K. Vanderpool
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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23
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Prezza G, Ryan D, Mädler G, Reichardt S, Barquist L, Westermann AJ. Comparative genomics provides structural and functional insights into Bacteroides RNA biology. Mol Microbiol 2021; 117:67-85. [PMID: 34379855 DOI: 10.1111/mmi.14793] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 08/05/2021] [Accepted: 08/09/2021] [Indexed: 11/30/2022]
Abstract
Bacteria employ noncoding RNA molecules for a wide range of biological processes, including scaffolding large molecular complexes, catalyzing chemical reactions, defending against phages, and controlling gene expression. Secondary structures, binding partners, and molecular mechanisms have been determined for numerous small noncoding RNAs (sRNAs) in model aerobic bacteria. However, technical hurdles have largely prevented analogous analyses in the anaerobic gut microbiota. While experimental techniques are being developed to investigate the sRNAs of gut commensals, computational tools and comparative genomics can provide immediate functional insight. Here, using Bacteroides thetaiotaomicron as a representative microbiota member, we illustrate how comparative genomics improves our understanding of the RNA biology in an understudied gut bacterium. We investigate putative RNA-binding proteins and predict a Bacteroides cold-shock protein homologue to have an RNA-related function. We apply an in-silico protocol incorporating both sequence and structural analysis to determine the consensus structures and conservation of nine Bacteroides noncoding RNA families. Using structure probing, we validate and refine these predictions, and deposit them in the Rfam database. Through synteny analyses, we illustrate how genomic co-conservation can serve as a predictor of sRNA function. Altogether, this work showcases the power of RNA informatics for investigating the RNA biology of anaerobic microbiota members.
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Affiliation(s)
- Gianluca Prezza
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Daniel Ryan
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Gohar Mädler
- Institute of Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany
| | - Sarah Reichardt
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany.,Faculty of Medicine, University of Würzburg, Würzburg, Germany
| | - Alexander J Westermann
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany.,Institute of Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany
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24
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Small RNAs go global in human gut Bacteroides. J Bacteriol 2021; 203:e0038321. [PMID: 34370557 DOI: 10.1128/jb.00383-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The last two decades have seen numerous studies connecting physiological behaviors in Bacteroides-including polysaccharide degradation and capsule production-with elements of global regulation, but a complete model is still elusive. A new study by Adams et al. in this issue of the Journal of Bacteriology reveals another layer of regulation by describing a novel family of RNA-binding proteins (Rbps) in Bacteroides thetaiotaomicron that modify expression of genes involved in carbohydrate utilization and capsule expression, among others.
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25
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Zhang Y, Thompson KN, Branck T, Yan Yan, Nguyen LH, Franzosa EA, Huttenhower C. Metatranscriptomics for the Human Microbiome and Microbial Community Functional Profiling. Annu Rev Biomed Data Sci 2021; 4:279-311. [PMID: 34465175 DOI: 10.1146/annurev-biodatasci-031121-103035] [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] [Indexed: 11/09/2022]
Abstract
Shotgun metatranscriptomics (MTX) is an increasingly practical way to survey microbial community gene function and regulation at scale. This review begins by summarizing the motivations for community transcriptomics and the history of the field. We then explore the principles, best practices, and challenges of contemporary MTX workflows: beginning with laboratory methods for isolation and sequencing of community RNA, followed by informatics methods for quantifying RNA features, and finally statistical methods for detecting differential expression in a community context. In thesecond half of the review, we survey important biological findings from the MTX literature, drawing examples from the human microbiome, other (nonhuman) host-associated microbiomes, and the environment. Across these examples, MTX methods prove invaluable for probing microbe-microbe and host-microbe interactions, the dynamics of energy harvest and chemical cycling, and responses to environmental stresses. We conclude with a review of open challenges in the MTX field, including making assays and analyses more robust, accessible, and adaptable to new technologies; deciphering roles for millions of uncharacterized microbial transcripts; and solving applied problems such as biomarker discovery and development of microbial therapeutics.
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Affiliation(s)
- Yancong Zhang
- Harvard Chan Microbiome in Public Health Center and Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, USA; , .,Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Kelsey N Thompson
- Harvard Chan Microbiome in Public Health Center and Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, USA; , .,Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Tobyn Branck
- Harvard Chan Microbiome in Public Health Center and Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, USA; , .,Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.,Department of Systems, Synthetic, and Quantitative Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Yan Yan
- Harvard Chan Microbiome in Public Health Center and Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, USA; , .,Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Long H Nguyen
- Harvard Chan Microbiome in Public Health Center and Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, USA; , .,Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.,Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02108, USA
| | - Eric A Franzosa
- Harvard Chan Microbiome in Public Health Center and Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, USA; , .,Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Curtis Huttenhower
- Harvard Chan Microbiome in Public Health Center and Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, USA; , .,Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.,Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115, USA
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26
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Ponath F, Tawk C, Zhu Y, Barquist L, Faber F, Vogel J. RNA landscape of the emerging cancer-associated microbe Fusobacterium nucleatum. Nat Microbiol 2021; 6:1007-1020. [PMID: 34239075 DOI: 10.1038/s41564-021-00927-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 05/24/2021] [Indexed: 12/14/2022]
Abstract
Fusobacterium nucleatum, long known as a constituent of the oral microflora, has recently garnered renewed attention for its association with several different human cancers. The growing interest in this emerging cancer-associated bacterium contrasts with a paucity of knowledge about its basic gene expression features and physiological responses. As fusobacteria lack all established small RNA-associated proteins, post-transcriptional networks in these bacteria are also unknown. In the present study, using differential RNA-sequencing, we generate high-resolution global RNA maps for five clinically relevant fusobacterial strains-F. nucleatum subspecies nucleatum, animalis, polymorphum and vincentii, as well as F. periodonticum-for early, mid-exponential growth and early stationary phase. These data are made available in an online browser, and we use these to uncover fundamental aspects of fusobacterial gene expression architecture and a suite of non-coding RNAs. Developing a vector for functional analysis of fusobacterial genes, we discover a conserved fusobacterial oxygen-induced small RNA, FoxI, which serves as a post-transcriptional repressor of the major outer membrane porin FomA. Our findings provide a crucial step towards delineating the regulatory networks enabling F. nucleatum adaptation to different environments, which may elucidate how these bacteria colonize different compartments of the human body.
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Affiliation(s)
- Falk Ponath
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Caroline Tawk
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Yan Zhu
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany.,Faculty of Medicine, University of Würzburg, Würzburg, Germany
| | - Franziska Faber
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Jörg Vogel
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany. .,Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany. .,Faculty of Medicine, University of Würzburg, Würzburg, Germany.
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27
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Guérin C, Lee BH, Fradet B, van Dijk E, Mirauta B, Thermes C, Bernardet JF, Repoila F, Duchaud E, Nicolas P, Rochat T. Transcriptome architecture and regulation at environmental transitions in flavobacteria: the case of an important fish pathogen. ISME COMMUNICATIONS 2021; 1:33. [PMID: 36739365 PMCID: PMC9723704 DOI: 10.1038/s43705-021-00029-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/07/2021] [Indexed: 02/06/2023]
Abstract
The family Flavobacteriaceae (phylum Bacteroidetes) is a major component of soil, marine and freshwater ecosystems. In this understudied family, Flavobacterium psychrophilum is a freshwater pathogen that infects salmonid fish worldwide, with critical environmental and economic impact. Here, we report an extensive transcriptome analysis that established the genome map of transcription start sites and transcribed regions, predicted alternative sigma factor regulons and regulatory RNAs, and documented gene expression profiles across 32 biological conditions mimicking the pathogen life cycle. The results link genes to environmental conditions and phenotypic traits and provide insights into gene regulation, highlighting similarities with better known bacteria and original characteristics linked to the phylogenetic position and the ecological niche of the bacterium. In particular, osmolarity appears as a signal for transition between free-living and within-host programs and expression patterns of secreted proteins shed light on probable virulence factors. Further investigations showed that a newly discovered sRNA widely conserved in the genus, Rfp18, is required for precise expression of proteases. By pointing proteins and regulatory elements probably involved in host-pathogen interactions, metabolic pathways, and molecular machineries, the results suggest many directions for future research; a website is made available to facilitate their use to fill knowledge gaps on flavobacteria.
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Affiliation(s)
- Cyprien Guérin
- Université Paris-Saclay, INRAE, MaIAGE, 78350, Jouy-en-Josas, France
| | - Bo-Hyung Lee
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350, Jouy-en-Josas, France
| | - Benjamin Fradet
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350, Jouy-en-Josas, France
| | - Erwin van Dijk
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Bogdan Mirauta
- Sorbonne Université, CNRS, IBPS, Laboratoire de Biologie Computationnelle et Quantitative (LCQB), 75005, Paris, France
| | - Claude Thermes
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | | | - Francis Repoila
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Eric Duchaud
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350, Jouy-en-Josas, France
| | - Pierre Nicolas
- Université Paris-Saclay, INRAE, MaIAGE, 78350, Jouy-en-Josas, France.
| | - Tatiana Rochat
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350, Jouy-en-Josas, France.
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28
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An RNA-centric global view of Clostridioides difficile reveals broad activity of Hfq in a clinically important gram-positive bacterium. Proc Natl Acad Sci U S A 2021; 118:2103579118. [PMID: 34131082 PMCID: PMC8237595 DOI: 10.1073/pnas.2103579118] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The gram-positive human pathogen Clostridioides difficile has emerged as the leading cause of antibiotic-associated diarrhea. However, little is known about the bacterium's transcriptome architecture and mechanisms of posttranscriptional control. Here, we have applied transcription start site and termination mapping to generate a single-nucleotide-resolution RNA map of C. difficile 5' and 3' untranslated regions, operon structures, and noncoding regulators, including 42 sRNAs. Our results indicate functionality of many conserved riboswitches and predict cis-regulatory RNA elements upstream of multidrug resistance (MDR)-type ATP-binding cassette (ABC) transporters and transcriptional regulators. Despite growing evidence for a role of Hfq in RNA-based gene regulation in C. difficile, the functions of Hfq-based posttranscriptional regulatory networks in gram-positive pathogens remain controversial. Using Hfq immunoprecipitation followed by sequencing of bound RNA species (RIP-seq), we identify a large cohort of transcripts bound by Hfq and show that absence of Hfq affects transcript stabilities and steady-state levels. We demonstrate sRNA expression during intestinal colonization by C. difficile and identify infection-related signals impacting its expression. As a proof of concept, we show that the utilization of the abundant intestinal metabolite ethanolamine is regulated by the Hfq-dependent sRNA CDIF630nc_085. Overall, our study lays the foundation for understanding clostridial riboregulation with implications for the infection process and provides evidence for a global role of Hfq in posttranscriptional regulation in a gram-positive bacterium.
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29
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Mortimer M, Wang Y, Holden PA. Molecular Mechanisms of Nanomaterial-Bacterial Interactions Revealed by Omics-The Role of Nanomaterial Effect Level. Front Bioeng Biotechnol 2021; 9:683520. [PMID: 34195180 PMCID: PMC8236600 DOI: 10.3389/fbioe.2021.683520] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 05/18/2021] [Indexed: 12/21/2022] Open
Abstract
Nanotechnology is employed across a wide range of antibacterial applications in clinical settings, food, pharmaceutical and textile industries, water treatment and consumer goods. Depending on type and concentration, engineered nanomaterials (ENMs) can also benefit bacteria in myriad contexts including within the human body, in biotechnology, environmental bioremediation, wastewater treatment, and agriculture. However, to realize the full potential of nanotechnology across broad applications, it is necessary to understand conditions and mechanisms of detrimental or beneficial effects of ENMs to bacteria. To study ENM effects, bacterial population growth or viability are commonly assessed. However, such endpoints alone may be insufficiently sensitive to fully probe ENM effects on bacterial physiology. To reveal more thoroughly how bacteria respond to ENMs, molecular-level omics methods such as transcriptomics, proteomics, and metabolomics are required. Because omics methods are increasingly utilized, a body of literature exists from which to synthesize state-of-the-art knowledge. Here we review relevant literature regarding ENM impacts on bacterial cellular pathways obtained by transcriptomic, proteomic, and metabolomic analyses across three growth and viability effect levels: inhibitory, sub-inhibitory or stimulatory. As indicated by our analysis, a wider range of pathways are affected in bacteria at sub-inhibitory vs. inhibitory ENM effect levels, underscoring the importance of ENM exposure concentration in elucidating ENM mechanisms of action and interpreting omics results. In addition, challenges and future research directions of applying omics approaches in studying bacterial-ENM interactions are discussed.
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Affiliation(s)
- Monika Mortimer
- Institute of Environmental and Health Sciences, College of Quality and Safety Engineering, China Jiliang University, Hangzhou, China
| | - Ying Wang
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Patricia A Holden
- Bren School of Environmental Science and Management and Earth Research Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
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30
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Otaru N, Ye K, Mujezinovic D, Berchtold L, Constancias F, Cornejo FA, Krzystek A, de Wouters T, Braegger C, Lacroix C, Pugin B. GABA Production by Human Intestinal Bacteroides spp.: Prevalence, Regulation, and Role in Acid Stress Tolerance. Front Microbiol 2021; 12:656895. [PMID: 33936013 PMCID: PMC8082179 DOI: 10.3389/fmicb.2021.656895] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/24/2021] [Indexed: 12/11/2022] Open
Abstract
The high neuroactive potential of metabolites produced by gut microbes has gained traction over the last few years, with metagenomic-based studies suggesting an important role of microbiota-derived γ-aminobutyric acid (GABA) in modulating mental health. Emerging evidence has revealed the presence of the glutamate decarboxylase (GAD)-encoding gene, a key enzyme to produce GABA, in the prominent human intestinal genus Bacteroides. Here, we investigated GABA production by Bacteroides in culture and metabolic assays combined with comparative genomics and phylogenetics. A total of 961 Bacteroides genomes were analyzed in silico and 17 metabolically and genetically diverse human intestinal isolates representing 11 species were screened in vitro. Using the model organism Bacteroides thetaiotaomicron DSM 2079, we determined GABA production kinetics, its impact on milieu pH, and we assessed its role in mitigating acid-induced cellular damage. We showed that the GAD-system consists of at least four highly conserved genes encoding a GAD, a glutaminase, a glutamate/GABA antiporter, and a potassium channel. We demonstrated a high prevalence of the GAD-system among Bacteroides with 90% of all Bacteroides genomes (96% in human gut isolates only) harboring all genes of the GAD-system and 16 intestinal Bacteroides strains producing GABA in vitro (ranging from 0.09 to 60.84 mM). We identified glutamate and glutamine as precursors of GABA production, showed that the production is regulated by pH, and that the GAD-system acts as a protective mechanism against acid stress in Bacteroides, mitigating cell death and preserving metabolic activity. Our data also indicate that the GAD-system might represent the only amino acid-dependent acid tolerance system in Bacteroides. Altogether, our results suggest an important contribution of Bacteroides in the regulation of the GABAergic system in the human gut.
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Affiliation(s)
- Nize Otaru
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland.,Nutrition Research Unit, University Children's Hospital Zürich, Zürich, Switzerland
| | - Kun Ye
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Denisa Mujezinovic
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Laura Berchtold
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland.,PharmaBiome AG, Zürich, Switzerland
| | - Florentin Constancias
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Fabián A Cornejo
- Max Planck Unit for the Science of Pathogens, Berlin, Germany.,Laboratory of Molecular Microbiology, Faculty of Chemistry and Biology, University of Santiago, Santiago, Chile
| | - Adam Krzystek
- Laboratory of Human Nutrition, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | | | - Christian Braegger
- Nutrition Research Unit, University Children's Hospital Zürich, Zürich, Switzerland
| | - Christophe Lacroix
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Benoit Pugin
- Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
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31
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Del Pozo-Acebo L, López de Las Hazas MC, Margollés A, Dávalos A, García-Ruiz A. Eating microRNAs: pharmacological opportunities for cross-kingdom regulation and implications in host gene and gut microbiota modulation. Br J Pharmacol 2021; 178:2218-2245. [PMID: 33644849 DOI: 10.1111/bph.15421] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 01/28/2021] [Accepted: 02/13/2021] [Indexed: 02/06/2023] Open
Abstract
Cross-kingdom communication via non-coding RNAs is a recent discovery. Exogenous microRNAs (exog-miRNAs) mainly enter the host via the diet. Generally considered unstable in the gastrointestinal tract, some exogenous RNAs may resist these conditions, especially if transported in extracellular vesicles. They could then reach the intestines and more probably exert a regulatory effect. We give an overview of recent discoveries concerning dietary miRNAs, possible ways of enhancing their resistance to food processing and gut conditions, their transport in extracellular vesicles (animal- and plant-origin) and possible biological effects on recipient cells after ingestion. We critically focus on what we believe are the most relevant data for future pharmacological development of dietary miRNAs as therapeutic agents. Finally, we discuss the miRNA-mediated cross-kingdom regulation between diet, host and the gut microbiota. We conclude that, despite many obstacles and challenges, extracellular miRNAs are serious candidates to be targeted pharmacologically for development of new therapeutic agents.
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Affiliation(s)
- Lorena Del Pozo-Acebo
- Madrid Institute for Advanced Studies (IMDEA)-Food, Laboratory of Epigenetics of Lipid Metabolism, Madrid, Spain
| | | | - Abelardo Margollés
- Institute of Dairy Products of Asturias (IPLA-CSIC), Villaviciosa, Spain.,Health Research Institute of Asturias (ISPA), Oviedo, Spain
| | - Alberto Dávalos
- Madrid Institute for Advanced Studies (IMDEA)-Food, Laboratory of Epigenetics of Lipid Metabolism, Madrid, Spain
| | - Almudena García-Ruiz
- Madrid Institute for Advanced Studies (IMDEA)-Food, Laboratory of Epigenetics of Lipid Metabolism, Madrid, Spain.,Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, California, USA
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32
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Westermann AJ, Vogel J. Cross-species RNA-seq for deciphering host-microbe interactions. Nat Rev Genet 2021; 22:361-378. [PMID: 33597744 DOI: 10.1038/s41576-021-00326-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2021] [Indexed: 02/08/2023]
Abstract
The human body is constantly exposed to microorganisms, which entails manifold interactions between human cells and diverse commensal or pathogenic bacteria. The cellular states of the interacting cells are decisive for the outcome of these encounters such as whether bacterial virulence programmes and host defence or tolerance mechanisms are induced. This Review summarizes how next-generation RNA sequencing (RNA-seq) has become a primary technology to study host-microbe interactions with high resolution, improving our understanding of the physiological consequences and the mechanisms at play. We illustrate how the discriminatory power and sensitivity of RNA-seq helps to dissect increasingly complex cellular interactions in time and space down to the single-cell level. We also outline how future transcriptomics may answer currently open questions in host-microbe interactions and inform treatment schemes for microbial disorders.
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Affiliation(s)
- Alexander J Westermann
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany. .,Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany.
| | - Jörg Vogel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany. .,Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany.
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33
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Lin L, Trabi EB, Xie F, Mao S. Comparison of the fermentation and bacterial community in the colon of Hu sheep fed a low-grain, non-pelleted, or pelleted high-grain diet. Appl Microbiol Biotechnol 2021; 105:2071-2080. [PMID: 33559720 DOI: 10.1007/s00253-021-11158-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/13/2021] [Accepted: 01/20/2021] [Indexed: 10/22/2022]
Abstract
Microbial fermentation in the hindgut is likely an important contributor to energy availability in ruminants, except for the rumen. This study aimed to investigate commensal bacteria in the colon influenced by diverse dietary niches. Fifteen male sheep were randomly allotted into three feeding groups: non-pelleted low-grain (CON, n = 5), non-pelleted high-grain (HG, n = 5), and pelleted high-grain (HP, n = 5) diets. The HG and HP groups had higher fermentation parameters than the CON group, especially acetate concentration (CON = 46.91; HG = 61.66; HP = 77.99). The HG diet altered the composition of commensal bacteria in the colon in comparison to the CON group, including the increase of genera related to acetate production (e.g., Acetitomaculum spp.), butyrate production (e.g., Coprococcus spp. and Subdoligranulum spp.), and starch degradation (e.g., Prevotella spp., Roseburia spp., and Oscillibacter spp.). The colon functional compendium had co-alteration with taxonomic changes that indicated non-pelleted HG diet caused a detrimental colonic niche. The HP diet specifically promoted the abundance of Ruminococcus, Olsenella, and Alloprevotella genera to achieve the highest acetate concentration and decreased the starch-degrader Roseburia spp. and Oscillibacter spp. in contrast to the HG group. Our results provide a systematic view of the microbial fermentation, community, and functional guilds in colonic digesta and mucosa in regard to using an HP diet to maintain colonic niche homeostasis under the adverse influence of the HG diet.Key Points• Non-pelleted and pelleted high-grain diets altered sheep colonic fermentation.• Non-pelleted and pelleted high-grain diets resulted in diverse microbial composition.• The pelleted method ameliorated microbial functions compared with the high-grain diet.
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Affiliation(s)
- Limei Lin
- Centre for Ruminant Nutrition and Feed Engineering Technology Research, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ehab Bo Trabi
- Centre for Ruminant Nutrition and Feed Engineering Technology Research, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Fei Xie
- Centre for Ruminant Nutrition and Feed Engineering Technology Research, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Shengyong Mao
- Centre for Ruminant Nutrition and Feed Engineering Technology Research, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China. .,Nanjing Zhirun Biological Science and Technology Co., Ltd., No.19 Binhuai Avenue, Economic Development Zone, Lishui District, Nanjing City, Jiangsu Province, People's Republic of China.
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34
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Schmidt K, Engel P. Mechanisms underlying gut microbiota-host interactions in insects. J Exp Biol 2021; 224:224/2/jeb207696. [PMID: 33509844 DOI: 10.1242/jeb.207696] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Insects are the most diverse group of animals and colonize almost all environments on our planet. This diversity is reflected in the structure and function of the microbial communities inhabiting the insect digestive system. As in mammals, the gut microbiota of insects can have important symbiotic functions, complementing host nutrition, facilitating dietary breakdown or providing protection against pathogens. There is an increasing number of insect models that are experimentally tractable, facilitating mechanistic studies of gut microbiota-host interactions. In this Review, we will summarize recent findings that have advanced our understanding of the molecular mechanisms underlying the symbiosis between insects and their gut microbiota. We will open the article with a general introduction to the insect gut microbiota and then turn towards the discussion of particular mechanisms and molecular processes governing the colonization of the insect gut environment as well as the diverse beneficial roles mediated by the gut microbiota. The Review highlights that, although the gut microbiota of insects is an active field of research with implications for fundamental and applied science, we are still in an early stage of understanding molecular mechanisms. However, the expanding capability to culture microbiomes and to manipulate microbe-host interactions in insects promises new molecular insights from diverse symbioses.
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Affiliation(s)
- Konstantin Schmidt
- Department of Fundamental Microbiology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Philipp Engel
- Department of Fundamental Microbiology, University of Lausanne, 1015, Lausanne, Switzerland
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35
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Wen JD, Kuo ST, Chou HHD. The diversity of Shine-Dalgarno sequences sheds light on the evolution of translation initiation. RNA Biol 2020; 18:1489-1500. [PMID: 33349119 DOI: 10.1080/15476286.2020.1861406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Shine-Dalgarno (SD) sequences, the core element of prokaryotic ribosome-binding sites, facilitate mRNA translation by base-pair interaction with the anti-SD (aSD) sequence of 16S rRNA. In contrast to this paradigm, an inspection of thousands of prokaryotic species unravels tremendous SD sequence diversity both within and between genomes, whereas aSD sequences remain largely static. The pattern has led many to suggest unidentified mechanisms for translation initiation. Here we review known translation-initiation pathways in prokaryotes. Moreover, we seek to understand the cause and consequence of SD diversity through surveying recent advances in biochemistry, genomics, and high-throughput genetics. These findings collectively show: (1) SD:aSD base pairing is beneficial but nonessential to translation initiation. (2) The 5' untranslated region of mRNA evolves dynamically and correlates with organismal phylogeny and ecological niches. (3) Ribosomes have evolved distinct usage of translation-initiation pathways in different species. We propose a model portraying the SD diversity shaped by optimization of gene expression, adaptation to environments and growth demands, and the species-specific prerequisite of ribosomes to initiate translation. The model highlights the coevolution of ribosomes and mRNA features, leading to functional customization of the translation apparatus in each organism.
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Affiliation(s)
- Jin-Der Wen
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan.,Genome and Systems Biology Degree Program, Academia Sinica and National Taiwan University, Taipei, Taiwan
| | - Syue-Ting Kuo
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Hsin-Hung David Chou
- Genome and Systems Biology Degree Program, Academia Sinica and National Taiwan University, Taipei, Taiwan.,Department of Life Science, National Taiwan University, Taipei, Taiwan
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Ryan D, Prezza G, Westermann AJ. An RNA-centric view on gut Bacteroidetes. Biol Chem 2020; 402:55-72. [PMID: 33544493 DOI: 10.1515/hsz-2020-0230] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/21/2020] [Indexed: 01/26/2023]
Abstract
Bacteria employ noncoding RNAs to maintain cellular physiology, adapt global gene expression to fluctuating environments, sense nutrients, coordinate their interaction with companion microbes and host cells, and protect themselves against bacteriophages. While bacterial RNA research has made fundamental contributions to biomedicine and biotechnology, the bulk of our knowledge of RNA biology stems from the study of a handful of aerobic model species. In comparison, RNA research is lagging in many medically relevant obligate anaerobic species, in particular the numerous commensal bacteria comprising our gut microbiota. This review presents a guide to RNA-based regulatory mechanisms in the phylum Bacteroidetes, focusing on the most abundant bacterial genus in the human gut, Bacteroides spp. This includes recent case reports on riboswitches, an mRNA leader, cis- and trans-encoded small RNAs (sRNAs) in Bacteroides spp., and a survey of CRISPR-Cas systems across Bacteroidetes. Recent work from our laboratory now suggests the existence of hundreds of noncoding RNA candidates in Bacteroides thetaiotaomicron, the emerging model organism for functional microbiota research. Based on these collective observations, we predict mechanistic and functional commonalities and differences between Bacteroides sRNAs and those of other model bacteria, and outline open questions and tools needed to boost Bacteroidetes RNA research.
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Affiliation(s)
- Daniel Ryan
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Josef-Schneider-Str. 2/D15, D-97080, Würzburg, Germany
| | - Gianluca Prezza
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Josef-Schneider-Str. 2/D15, D-97080, Würzburg, Germany
| | - Alexander J Westermann
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Josef-Schneider-Str. 2/D15, D-97080, Würzburg, Germany.,Institute of Molecular Infection Biology (IMIB), University of Würzburg, Josef-Schneider-Str. 2/D15, D-97080, Würzburg, Germany
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