1
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Weiler JR, Jürgensen N, Cornejo Infante M, Knoll MT, Gescher J. Strain and model development for auto- and heterotrophic 2,3-butanediol production using Cupriavidus necator H16. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:108. [PMID: 39080797 PMCID: PMC11290209 DOI: 10.1186/s13068-024-02549-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 07/03/2024] [Indexed: 08/02/2024]
Abstract
The production of platform chemicals from renewable energy sources is a crucial step towards a post-fossil economy. This study reports on the production of acetoin and 2,3-butanediol heterotrophically with fructose as substrate and autotrophically from CO2 as carbon source, H2 as electron donor and O2 as electron acceptor with Cupriavidus necator. In a previous study, the strain was developed for the production of acetoin with high carbon efficiency. Acetoin can serve as a precursor for the synthesis of 2,3-butanediol by the integration of a butanediol dehydrogenase. In this study, different plasmid backbones and butanediol dehydrogenases were evaluated regarding efficiency for CO2-based 2,3-butanediol production. The developed strain utilizes the pBBR1 plasmid bearing a 2,3-butanediol dehydrogenase from Enterobacter cloacae and is characterized by 2,3-butanediol as the main product and a heterotrophic total product yield of 88.11%, an autotrophic volumetric productivity of 39.45 mg L-1 h-1, a total product carbon yield of 81.6%, an H2 efficiency of 33.46%, and a specific productivity of 0.016 g product per gram of biomass per hour. In addition, a mathematical model was developed to simulate the processes under these conditions. With this model, it was possible to calculate productivities and substrate usage at distinct time points of the production processes and calculate productivities and substrate usage with high resolution which will be useful in future applications.
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Affiliation(s)
- Janek R Weiler
- Institute of Technical Microbiology, Hamburg University of Technology, 21073, Hamburg, Germany
| | - Nikolai Jürgensen
- Institute of Technical Microbiology, Hamburg University of Technology, 21073, Hamburg, Germany
| | - Monica Cornejo Infante
- Institute of Technical Microbiology, Hamburg University of Technology, 21073, Hamburg, Germany
| | - Melanie T Knoll
- Institute of Technical Microbiology, Hamburg University of Technology, 21073, Hamburg, Germany
| | - Johannes Gescher
- Institute of Technical Microbiology, Hamburg University of Technology, 21073, Hamburg, Germany.
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2
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Ábrahám Á, Dér L, Csákvári E, Vizsnyiczai G, Pap I, Lukács R, Varga-Zsíros V, Nagy K, Galajda P. Single-cell level LasR-mediated quorum sensing response of Pseudomonas aeruginosa to pulses of signal molecules. Sci Rep 2024; 14:16181. [PMID: 39003361 PMCID: PMC11246452 DOI: 10.1038/s41598-024-66706-6] [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: 09/04/2023] [Accepted: 07/03/2024] [Indexed: 07/15/2024] Open
Abstract
Quorum sensing (QS) is a communication form between bacteria via small signal molecules that enables global gene regulation as a function of cell density. We applied a microfluidic mother machine to study the kinetics of the QS response of Pseudomonas aeruginosa bacteria to additions and withdrawals of signal molecules. We traced the fast buildup and the subsequent considerably slower decay of a population-level and single-cell-level QS response. We applied a mathematical model to explain the results quantitatively. We found significant heterogeneity in QS on the single-cell level, which may result from variations in quorum-controlled gene expression and protein degradation. Heterogeneity correlates with cell lineage history, too. We used single-cell data to define and quantitatively characterize the population-level quorum state. We found that the population-level QS response is well-defined. The buildup of the quorum is fast upon signal molecule addition. At the same time, its decay is much slower following signal withdrawal, and the quorum may be maintained for several hours in the absence of the signal. Furthermore, the quorum sensing response of the population was largely repeatable in subsequent pulses of signal molecules.
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Affiliation(s)
- Ágnes Ábrahám
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary
- Doctoral School of Multidisciplinary Medical Sciences, University of Szeged, Dóm Tér 9, Szeged, 6720, Hungary
| | - László Dér
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Eszter Csákvári
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary
- Division for Biotechnology, Bay Zoltán Nonprofit Ltd. for Applied Research, Derkovits Fasor 2., Szeged, 6726, Hungary
| | - Gaszton Vizsnyiczai
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Imre Pap
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary
- Doctoral School of Multidisciplinary Medical Sciences, University of Szeged, Dóm Tér 9, Szeged, 6720, Hungary
| | - Rebeka Lukács
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Vanda Varga-Zsíros
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary
- HUN-REN Biological Research Centre, Institute of Biochemistry, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Krisztina Nagy
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary.
| | - Péter Galajda
- HUN-REN Biological Research Centre, Institute of Biophysics, Temesvári Krt. 62, Szeged, 6726, Hungary.
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3
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Joshi SHN, Jenkins C, Ulaeto D, Gorochowski TE. Accelerating Genetic Sensor Development, Scale-up, and Deployment Using Synthetic Biology. BIODESIGN RESEARCH 2024; 6:0037. [PMID: 38919711 PMCID: PMC11197468 DOI: 10.34133/bdr.0037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/23/2024] [Indexed: 06/27/2024] Open
Abstract
Living cells are exquisitely tuned to sense and respond to changes in their environment. Repurposing these systems to create engineered biosensors has seen growing interest in the field of synthetic biology and provides a foundation for many innovative applications spanning environmental monitoring to improved biobased production. In this review, we present a detailed overview of currently available biosensors and the methods that have supported their development, scale-up, and deployment. We focus on genetic sensors in living cells whose outputs affect gene expression. We find that emerging high-throughput experimental assays and evolutionary approaches combined with advanced bioinformatics and machine learning are establishing pipelines to produce genetic sensors for virtually any small molecule, protein, or nucleic acid. However, more complex sensing tasks based on classifying compositions of many stimuli and the reliable deployment of these systems into real-world settings remain challenges. We suggest that recent advances in our ability to precisely modify nonmodel organisms and the integration of proven control engineering principles (e.g., feedback) into the broader design of genetic sensing systems will be necessary to overcome these hurdles and realize the immense potential of the field.
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Affiliation(s)
| | - Christopher Jenkins
- CBR Division, Defence Science and Technology Laboratory, Porton Down, Wiltshire SP4 0JQ, UK
| | - David Ulaeto
- CBR Division, Defence Science and Technology Laboratory, Porton Down, Wiltshire SP4 0JQ, UK
| | - Thomas E. Gorochowski
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
- BrisEngBio,
School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
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4
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Kumar S, Lezia A, Hasty J. Engineering plasmid copy number heterogeneity for dynamic microbial adaptation. Nat Microbiol 2024:10.1038/s41564-024-01706-w. [PMID: 38890490 DOI: 10.1038/s41564-024-01706-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 04/19/2024] [Indexed: 06/20/2024]
Abstract
Natural microbial populations exploit phenotypic heterogeneity for survival and adaptation. However, in engineering biology, limiting the sources of variability is a major focus. Here we show that intentionally coupling distinct plasmids via shared replication mechanisms enables bacterial populations to adapt to their environment. We demonstrate that plasmid coupling of carbon-metabolizing operons facilitates copy number tuning of an essential but burdensome construct through the action of a stably maintained, non-essential plasmid. For specific cost-benefit situations, incompatible two-plasmid systems can stably persist longer than compatible ones. We also show using microfluidics that plasmid coupling of synthetic constructs generates population-state memory of previous environmental adaptation without additional regulatory control. This work should help to improve the design of synthetic populations by enabling adaptive engineered strains to function under changing growth conditions without strict fine-tuning of the genetic circuitry.
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Affiliation(s)
- Shalni Kumar
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA.
| | - Andrew Lezia
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Jeff Hasty
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
- Molecular Biology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
- Synthetic Biology Institute, University of California, San Diego, San Diego, CA, USA
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5
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Rothschild LJ, Averesch NJH, Strychalski EA, Moser F, Glass JI, Cruz Perez R, Yekinni IO, Rothschild-Mancinelli B, Roberts Kingman GA, Wu F, Waeterschoot J, Ioannou IA, Jewett MC, Liu AP, Noireaux V, Sorenson C, Adamala KP. Building Synthetic Cells─From the Technology Infrastructure to Cellular Entities. ACS Synth Biol 2024; 13:974-997. [PMID: 38530077 PMCID: PMC11037263 DOI: 10.1021/acssynbio.3c00724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/01/2024] [Accepted: 02/06/2024] [Indexed: 03/27/2024]
Abstract
The de novo construction of a living organism is a compelling vision. Despite the astonishing technologies developed to modify living cells, building a functioning cell "from scratch" has yet to be accomplished. The pursuit of this goal alone has─and will─yield scientific insights affecting fields as diverse as cell biology, biotechnology, medicine, and astrobiology. Multiple approaches have aimed to create biochemical systems manifesting common characteristics of life, such as compartmentalization, metabolism, and replication and the derived features, evolution, responsiveness to stimuli, and directed movement. Significant achievements in synthesizing each of these criteria have been made, individually and in limited combinations. Here, we review these efforts, distinguish different approaches, and highlight bottlenecks in the current research. We look ahead at what work remains to be accomplished and propose a "roadmap" with key milestones to achieve the vision of building cells from molecular parts.
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Affiliation(s)
- Lynn J. Rothschild
- Space Science
& Astrobiology Division, NASA Ames Research
Center, Moffett
Field, California 94035-1000, United States
- Department
of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Nils J. H. Averesch
- Department
of Civil and Environmental Engineering, Stanford University, Stanford, California 94305, United States
| | | | - Felix Moser
- Synlife, One Kendall Square, Cambridge, Massachusetts 02139-1661, United States
| | - John I. Glass
- J.
Craig
Venter Institute, La Jolla, California 92037, United States
| | - Rolando Cruz Perez
- Department
of Bioengineering, Stanford University, Stanford, California 94305, United States
- Blue
Marble
Space Institute of Science at NASA Ames Research Center, Moffett Field, California 94035-1000, United
States
| | - Ibrahim O. Yekinni
- Department
of Biomedical Engineering, University of
Minnesota, Minneapolis, Minnesota 55455, United States
| | - Brooke Rothschild-Mancinelli
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332-0150, United States
| | | | - Feilun Wu
- J. Craig
Venter Institute, Rockville, Maryland 20850, United States
| | - Jorik Waeterschoot
- Mechatronics,
Biostatistics and Sensors (MeBioS), KU Leuven, 3000 Leuven Belgium
| | - Ion A. Ioannou
- Department
of Chemistry, MSRH, Imperial College London, London W12 0BZ, U.K.
| | - Michael C. Jewett
- Department
of Bioengineering, Stanford University, Stanford, California 94305, United States
| | - Allen P. Liu
- Mechanical
Engineering & Biomedical Engineering, Cellular and Molecular Biology,
Biophysics, Applied Physics, University
of Michigan, Ann Arbor, Michigan 48109, United States
| | - Vincent Noireaux
- Physics
and Nanotechnology, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Carlise Sorenson
- Department
of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Katarzyna P. Adamala
- Department
of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455, United States
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6
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Eerlings R, Gupta P, Lee XY, Nguyen T, El Kharraz S, Handle F, Smeets E, Moris L, Devlies W, Vandewinkel B, Thiry I, Ta DT, Gorkovskiy A, Voordeckers K, Henckaerts E, Pinheiro VB, Claessens F, Verstrepen KJ, Voet A, Helsen C. Rational evolution for altering the ligand preference of estrogen receptor alpha. Protein Sci 2024; 33:e4940. [PMID: 38511482 PMCID: PMC10955623 DOI: 10.1002/pro.4940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 03/22/2024]
Abstract
Estrogen receptor α is commonly used in synthetic biology to control the activity of genome editing tools. The activating ligands, estrogens, however, interfere with various cellular processes, thereby limiting the applicability of this receptor. Altering its ligand preference to chemicals of choice solves this hurdle but requires adaptation of unspecified ligand-interacting residues. Here, we provide a solution by combining rational protein design with multi-site-directed mutagenesis and directed evolution of stably integrated variants in Saccharomyces cerevisiae. This method yielded an estrogen receptor variant, named TERRA, that lost its estrogen responsiveness and became activated by tamoxifen, an anti-estrogenic drug used for breast cancer treatment. This tamoxifen preference of TERRA was maintained in mammalian cells and mice, even when fused to Cre recombinase, expanding the mammalian synthetic biology toolbox. Not only is our platform transferable to engineer ligand preference of any steroid receptor, it can also profile drug-resistance landscapes for steroid receptor-targeted therapies.
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Affiliation(s)
- Roy Eerlings
- Molecular Endocrinology Laboratory, Department of Cellular and Molecular MedicineKU LeuvenLeuvenBelgium
- Laboratory of Systems BiologyVIB‐KU Leuven Center for MicrobiologyLeuvenBelgium
- Laboratory for Genetics and Genomics, Center of Microbial and Plant Genetics, Department M2SKU LeuvenHeverleeBelgium
| | - Purvi Gupta
- Laboratory of Biomolecular Modelling and Design, Department of ChemistryKU LeuvenHeverleeBelgium
| | - Xiao Yin Lee
- Molecular Endocrinology Laboratory, Department of Cellular and Molecular MedicineKU LeuvenLeuvenBelgium
| | - Tien Nguyen
- Laboratory of Biomolecular Modelling and Design, Department of ChemistryKU LeuvenHeverleeBelgium
| | - Sarah El Kharraz
- Molecular Endocrinology Laboratory, Department of Cellular and Molecular MedicineKU LeuvenLeuvenBelgium
| | - Florian Handle
- Molecular Endocrinology Laboratory, Department of Cellular and Molecular MedicineKU LeuvenLeuvenBelgium
| | - Elien Smeets
- Molecular Endocrinology Laboratory, Department of Cellular and Molecular MedicineKU LeuvenLeuvenBelgium
| | - Lisa Moris
- Molecular Endocrinology Laboratory, Department of Cellular and Molecular MedicineKU LeuvenLeuvenBelgium
- Department of UrologyUniversity Hospitals LeuvenLeuvenBelgium
| | - Wout Devlies
- Molecular Endocrinology Laboratory, Department of Cellular and Molecular MedicineKU LeuvenLeuvenBelgium
- Department of UrologyUniversity Hospitals LeuvenLeuvenBelgium
| | - Bram Vandewinkel
- Laboratory of Viral Cell Biology and Therapeutics, Department of Cellular and Molecular Medicine, Department of Microbiology, Immunology and TransplantationKU LeuvenLeuvenBelgium
| | - Irina Thiry
- Laboratory of Viral Cell Biology and Therapeutics, Department of Cellular and Molecular Medicine, Department of Microbiology, Immunology and TransplantationKU LeuvenLeuvenBelgium
| | - Duy Tien Ta
- Laboratory of Viral Cell Biology and Therapeutics, Department of Cellular and Molecular Medicine, Department of Microbiology, Immunology and TransplantationKU LeuvenLeuvenBelgium
| | - Anton Gorkovskiy
- Laboratory of Systems BiologyVIB‐KU Leuven Center for MicrobiologyLeuvenBelgium
- Laboratory for Genetics and Genomics, Center of Microbial and Plant Genetics, Department M2SKU LeuvenHeverleeBelgium
| | - Karin Voordeckers
- Laboratory of Systems BiologyVIB‐KU Leuven Center for MicrobiologyLeuvenBelgium
- Laboratory for Genetics and Genomics, Center of Microbial and Plant Genetics, Department M2SKU LeuvenHeverleeBelgium
| | - Els Henckaerts
- Laboratory of Viral Cell Biology and Therapeutics, Department of Cellular and Molecular Medicine, Department of Microbiology, Immunology and TransplantationKU LeuvenLeuvenBelgium
| | - Vitor B. Pinheiro
- KU Leuven, Department of Pharmaceutical and Pharmacological SciencesRega Institute for Medical ResearchLeuvenBelgium
| | - Frank Claessens
- Molecular Endocrinology Laboratory, Department of Cellular and Molecular MedicineKU LeuvenLeuvenBelgium
| | - Kevin J. Verstrepen
- Laboratory of Systems BiologyVIB‐KU Leuven Center for MicrobiologyLeuvenBelgium
- Laboratory for Genetics and Genomics, Center of Microbial and Plant Genetics, Department M2SKU LeuvenHeverleeBelgium
| | - Arnout Voet
- Laboratory of Biomolecular Modelling and Design, Department of ChemistryKU LeuvenHeverleeBelgium
| | - Christine Helsen
- Molecular Endocrinology Laboratory, Department of Cellular and Molecular MedicineKU LeuvenLeuvenBelgium
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7
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Hernandez-Beltran JCR, Rodríguez-Beltrán J, Aguilar-Luviano OB, Velez-Santiago J, Mondragón-Palomino O, MacLean RC, Fuentes-Hernández A, San Millán A, Peña-Miller R. Plasmid-mediated phenotypic noise leads to transient antibiotic resistance in bacteria. Nat Commun 2024; 15:2610. [PMID: 38521779 PMCID: PMC10960800 DOI: 10.1038/s41467-024-45045-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 01/12/2024] [Indexed: 03/25/2024] Open
Abstract
The rise of antibiotic resistance is a critical public health concern, requiring an understanding of mechanisms that enable bacteria to tolerate antimicrobial agents. Bacteria use diverse strategies, including the amplification of drug-resistance genes. In this paper, we showed that multicopy plasmids, often carrying antibiotic resistance genes in clinical bacteria, can rapidly amplify genes, leading to plasmid-mediated phenotypic noise and transient antibiotic resistance. By combining stochastic simulations of a computational model with high-throughput single-cell measurements of blaTEM-1 expression in Escherichia coli MG1655, we showed that plasmid copy number variability stably maintains populations composed of cells with both low and high plasmid copy numbers. This diversity in plasmid copy number enhances the probability of bacterial survival in the presence of antibiotics, while also rapidly reducing the burden of carrying multiple plasmids in drug-free environments. Our results further support the tenet that multicopy plasmids not only act as vehicles for the horizontal transfer of genetic information between cells but also as drivers of bacterial adaptation, enabling rapid modulation of gene copy numbers. Understanding the role of multicopy plasmids in antibiotic resistance is critical, and our study provides insights into how bacteria can transiently survive lethal concentrations of antibiotics.
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Affiliation(s)
- J Carlos R Hernandez-Beltran
- Center for Genomic Sciences, Universidad Nacional Autónoma de México, 62210, Cuernavaca, México.
- Department of Microbial Population Biology, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.
| | | | | | - Jesús Velez-Santiago
- Center for Genomic Sciences, Universidad Nacional Autónoma de México, 62210, Cuernavaca, México
| | - Octavio Mondragón-Palomino
- Laboratory of Parasitic Diseases, National Institute for Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - R Craig MacLean
- Department of Biology, University of Oxford, OX1 3SZ, Oxford, UK
| | - Ayari Fuentes-Hernández
- Center for Genomic Sciences, Universidad Nacional Autónoma de México, 62210, Cuernavaca, México
| | - Alvaro San Millán
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología - CSIC, 28049, Madrid, Spain
| | - Rafael Peña-Miller
- Center for Genomic Sciences, Universidad Nacional Autónoma de México, 62210, Cuernavaca, México.
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8
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Buson F, Gao Y, Wang B. Genetic Parts and Enabling Tools for Biocircuit Design. ACS Synth Biol 2024; 13:697-713. [PMID: 38427821 DOI: 10.1021/acssynbio.3c00691] [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: 03/03/2024]
Abstract
Synthetic biology aims to engineer biological systems for customized tasks through the bottom-up assembly of fundamental building blocks, which requires high-quality libraries of reliable, modular, and standardized genetic parts. To establish sets of parts that work well together, synthetic biologists created standardized part libraries in which every component is analyzed in the same metrics and context. Here we present a state-of-the-art review of the currently available part libraries for designing biocircuits and their gene expression regulation paradigms at transcriptional, translational, and post-translational levels in Escherichia coli. We discuss the necessary facets to integrate these parts into complex devices and systems along with the current efforts to catalogue and standardize measurement data. To better display the range of available parts and to facilitate part selection in synthetic biology workflows, we established biopartsDB, a curated database of well-characterized and useful genetic part and device libraries with detailed quantitative data validated by the published literature.
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Affiliation(s)
- Felipe Buson
- College of Chemical and Biological Engineering & ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310058, China
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, U.K
| | - Yuanli Gao
- College of Chemical and Biological Engineering & ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310058, China
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, U.K
| | - Baojun Wang
- College of Chemical and Biological Engineering & ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310058, China
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9
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Kozaeva E, Nielsen ZS, Nieto-Domínguez M, Nikel P. The pAblo·pCasso self-curing vector toolset for unconstrained cytidine and adenine base-editing in Gram-negative bacteria. Nucleic Acids Res 2024; 52:e19. [PMID: 38180826 PMCID: PMC10899774 DOI: 10.1093/nar/gkad1236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 12/11/2023] [Accepted: 01/02/2024] [Indexed: 01/07/2024] Open
Abstract
A synthetic biology toolkit, exploiting clustered regularly interspaced short palindromic repeats (CRISPR) and modified CRISPR-associated protein (Cas) base-editors, was developed for genome engineering in Gram-negative bacteria. Both a cytidine base-editor (CBE) and an adenine base-editor (ABE) have been optimized for precise single-nucleotide modification of plasmid and genome targets. CBE comprises a cytidine deaminase conjugated to a Cas9 nickase from Streptococcus pyogenes (SpnCas9), resulting in C→T (or G→A) substitutions. Conversely, ABE consists of an adenine deaminase fused to SpnCas9 for A→G (or T→C) editing. Several nucleotide substitutions were achieved using these plasmid-borne base-editing systems and a novel protospacer adjacent motif (PAM)-relaxed SpnCas9 (SpRY) variant. Base-editing was validated in Pseudomonas putida and other Gram-negative bacteria by inserting premature STOP codons into target genes, thereby inactivating both fluorescent proteins and metabolic (antibiotic-resistance) functions. The functional knockouts obtained by engineering STOP codons via CBE were reverted to the wild-type genotype using ABE. Additionally, a series of induction-responsive vectors was developed to facilitate the curing of the base-editing platform in a single cultivation step, simplifying complex strain engineering programs without relying on homologous recombination and yielding plasmid-free, modified bacterial cells.
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Affiliation(s)
- Ekaterina Kozaeva
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Zacharias S Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Manuel Nieto-Domínguez
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Pablo I Nikel
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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10
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Martinusen SG, Slaton EW, Nelson SE, Pulgar MA, Besu JT, Simas CF, Denard CA. Modular and integrative activity reporters enhance biochemical studies in the yeast ER. Protein Eng Des Sel 2024; 37:gzae008. [PMID: 38696722 DOI: 10.1093/protein/gzae008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 03/31/2024] [Accepted: 05/01/2024] [Indexed: 05/04/2024] Open
Abstract
The yeast endoplasmic reticulum sequestration and screening (YESS) system is a broadly applicable platform to perform high-throughput biochemical studies of post-translational modification enzymes (PTM-enzymes). This system enables researchers to profile and engineer the activity and substrate specificity of PTM-enzymes and to discover inhibitor-resistant enzyme mutants. In this study, we expand the capabilities of YESS by transferring its functional components to integrative plasmids. The YESS integrative system yields uniform protein expression and protease activities in various configurations, allows one to integrate activity reporters at two independent loci and to split the system between integrative and centromeric plasmids. We characterize these integrative reporters with two viral proteases, Tobacco etch virus (TEVp) and 3-chymotrypsin like protease (3CLpro), in terms of coefficient of variance, signal-to-noise ratio and fold-activation. Overall, we provide a framework for chromosomal-based studies that is modular, enabling rigorous high-throughput assays of PTM-enzymes in yeast.
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Affiliation(s)
| | - Ethan W Slaton
- Department of Chemical Engineering, University of Florida, Gainesville, 32611, USA
| | - Sage E Nelson
- Department of Chemical Engineering, University of Florida, Gainesville, 32611, USA
| | - Marian A Pulgar
- Department of Chemical Engineering, University of Florida, Gainesville, 32611, USA
| | - Julia T Besu
- Department of Biology, University of Florida, Gainesville, 32611, USA
| | - Cassidy F Simas
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, 32611, USA
| | - Carl A Denard
- Department of Chemical Engineering, University of Florida, Gainesville, 32611, USA
- UF Health Cancer Center, University of Florida, Gainesville, 32611, USA
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11
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Kruse L, Loeschcke A, de Witt J, Wierckx N, Jaeger K, Thies S. Halopseudomonas species: Cultivation and molecular genetic tools. Microb Biotechnol 2024; 17:e14369. [PMID: 37991430 PMCID: PMC10832565 DOI: 10.1111/1751-7915.14369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/24/2023] [Accepted: 10/26/2023] [Indexed: 11/23/2023] Open
Abstract
The Halopseudomonas species, formerly classified as Pseudomonas pertucinogena lineage, form a unique phylogenetic branch within the Pseudomonads. Most strains have recently been isolated from challenging habitats including oil- or metal-polluted sites, deep sea, and intertidal zones, suggesting innate resilience to physical and chemical stresses. Despite their comparably small genomes, these bacteria synthesise several biomolecules with biotechnological potential and a role in the degradation of anthropogenic pollutants has been suggested for some Halopseudomonads. Until now, these bacteria are not readily amenable to existing cultivation and cloning methods. We addressed these limitations by selecting four Halopseudomonas strains of particular interest, namely H. aestusnigri, H. bauzanensis, H. litoralis, and H. oceani to establish microbiological and molecular genetic methods. We found that C4 -C10 dicarboxylic acids serve as viable carbon sources in both complex and mineral salt cultivation media. We also developed plasmid DNA transfer protocols and assessed vectors with different origins of replication and promoters inducible with isopropyl-β-d-thiogalactopyranoside, l-arabinose, and salicylate. Furthermore, we have demonstrated the simultaneous genomic integration of expression cassettes into one and two attTn7 integration sites. Our results provide a valuable toolbox for constructing robust chassis strains and highlight the biotechnological potential of Halopseudomonas strains.
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Affiliation(s)
- Luzie Kruse
- Institute of Molecular Enzyme TechnologyHeinrich Heine UniversityDüsseldorfGermany
| | - Anita Loeschcke
- Institute of Molecular Enzyme TechnologyHeinrich Heine UniversityDüsseldorfGermany
| | - Jan de Witt
- Institute of Bio‐ and Geosciences IBG‐1: BiotechnologyJülichGermany
| | - Nick Wierckx
- Institute of Bio‐ and Geosciences IBG‐1: BiotechnologyJülichGermany
| | - Karl‐Erich Jaeger
- Institute of Molecular Enzyme TechnologyHeinrich Heine UniversityDüsseldorfGermany
- Institute of Bio‐ and Geosciences IBG‐1: BiotechnologyJülichGermany
| | - Stephan Thies
- Institute of Molecular Enzyme TechnologyHeinrich Heine UniversityDüsseldorfGermany
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12
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Tan Y, Liang J, Lai M, Wan S, Luo X, Li F. Advances in synthetic biology toolboxes paving the way for mechanistic understanding and strain engineering of gut commensal Bacteroides spp. and Clostridium spp. Biotechnol Adv 2023; 69:108272. [PMID: 37844770 DOI: 10.1016/j.biotechadv.2023.108272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 10/10/2023] [Accepted: 10/13/2023] [Indexed: 10/18/2023]
Abstract
The gut microbiota plays a significant role in influencing human immunity, metabolism, development, and behavior by producing a wide range of metabolites. While there is accumulating data on several microbiota-derived small molecules that contribute to host health and disease, our knowledge regarding the molecular mechanisms underlying metabolite-mediated microbe-host interactions remains limited. This is primarily due to the lack of efficient genetic tools for most commensal bacteria, especially those belonging to the dominant phyla Bacteroides spp. and Clostridium spp., which hinders the application of synthetic biology to these gut commensal bacteria. In this review, we provide an overview of recent advances in synthetic biology tools developed for the two dominant genera, as well as their applications in deciphering the mechanisms of microbe-host interactions mediated by microbiota-derived small molecules. We also discuss the potential biomedical applications of engineering commensal bacteria using these toolboxes. Finally, we share our perspective on the future development of synthetic biology tools for a better understanding of small molecule-mediated microbe-host interactions and their engineering for biomedical purposes.
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Affiliation(s)
- Yang Tan
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; Shandong Energy Institute, Qingdao 266101, China; Qingdao New Energy Shandong Laboratory, Qingdao 266101, China.
| | - Jing Liang
- Center for Synthetic Biochemistry, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Mingchi Lai
- College of Life Sciences, Qingdao Agricultural University, Qingdao 266109, China
| | - Sai Wan
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; Shandong Energy Institute, Qingdao 266101, China; Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
| | - Xiaozhou Luo
- Center for Synthetic Biochemistry, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Fuli Li
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao C1 Refinery Engineering Research Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; Shandong Energy Institute, Qingdao 266101, China; Qingdao New Energy Shandong Laboratory, Qingdao 266101, China.
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13
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Blázquez B, León DS, Torres-Bacete J, Gómez-Luengo Á, Kniewel R, Martínez I, Sordon S, Wilczak A, Salgado S, Huszcza E, Popłoński J, Prieto A, Nogales J. Golden Standard: a complete standard, portable, and interoperative MoClo tool for model and non-model proteobacteria. Nucleic Acids Res 2023; 51:e98. [PMID: 37718823 PMCID: PMC10602866 DOI: 10.1093/nar/gkad758] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 09/06/2023] [Indexed: 09/19/2023] Open
Abstract
Modular cloning has become a benchmark technology in synthetic biology. However, a notable disparity exists between its remarkable development and the need for standardization to facilitate seamless interoperability among systems. The field is thus impeded by an overwhelming proliferation of organism-specific systems that frequently lack compatibility. To overcome these issues, we present Golden Standard (GS), a Type IIS assembly method underpinned by the Standard European Vector Architecture. GS unlocks modular cloning applications for most bacteria, and delivers combinatorial multi-part assembly to create genetic circuits of up to twenty transcription units (TUs). Reliance on MoClo syntax renders GS fully compatible with many existing tools and it sets the path towards efficient reusability of available part libraries and assembled TUs. GS was validated in terms of DNA assembly, portability, interoperability and phenotype engineering in α-, β-, γ- and δ-proteobacteria. Furthermore, we provide a computational pipeline for parts characterization that was used to assess the performance of GS parts. To promote community-driven development of GS, we provide a dedicated web-portal including a repository of parts, vectors, and Wizard and Setup tools that guide users in designing constructs. Overall, GS establishes an open, standardized framework propelling the progress of synthetic biology as a whole.
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Affiliation(s)
- Blas Blázquez
- Department of Systems Biology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), Madrid, Spain
| | - David San León
- Department of Systems Biology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), Madrid, Spain
| | - Jesús Torres-Bacete
- Department of Systems Biology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Álvaro Gómez-Luengo
- Department of Systems Biology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), Madrid, Spain
| | - Ryan Kniewel
- Microbial and Plant Biotechnology Department, Biological Research Center-Margarita Salas, CSIC, Madrid, Spain
| | - Igor Martínez
- Department of Systems Biology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Sandra Sordon
- Wrocław University of Environmental and Life Sciences, Department of Food Chemistry and Biocatalysis, Norwida 25, 50-375, Wrocław, Poland
| | - Aleksandra Wilczak
- Wrocław University of Environmental and Life Sciences, Department of Food Chemistry and Biocatalysis, Norwida 25, 50-375, Wrocław, Poland
| | - Sergio Salgado
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), Madrid, Spain
- Microbial and Plant Biotechnology Department, Biological Research Center-Margarita Salas, CSIC, Madrid, Spain
| | - Ewa Huszcza
- Wrocław University of Environmental and Life Sciences, Department of Food Chemistry and Biocatalysis, Norwida 25, 50-375, Wrocław, Poland
| | - Jarosław Popłoński
- Wrocław University of Environmental and Life Sciences, Department of Food Chemistry and Biocatalysis, Norwida 25, 50-375, Wrocław, Poland
| | - Auxiliadora Prieto
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), Madrid, Spain
- Microbial and Plant Biotechnology Department, Biological Research Center-Margarita Salas, CSIC, Madrid, Spain
| | - Juan Nogales
- Department of Systems Biology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), Madrid, Spain
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14
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Kretz J, Israel V, McIntosh M. Design-Build-Test of Synthetic Promoters for Inducible Gene Regulation in Alphaproteobacteria. ACS Synth Biol 2023; 12:2663-2675. [PMID: 37561940 DOI: 10.1021/acssynbio.3c00251] [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: 08/12/2023]
Abstract
Inducible gene expression is useful for biotechnological applications and for studying gene regulation and function in bacteria. Many inducible systems that perform in model organisms such as the Gammaproteobacterium Escherichia coli do not perform well in other bacteria that are of biotechnological interest. Typical problems include weak or leaky expression. Here, we describe an invention named ACIT (Alphaproteobacteria chromosomally integrating transcription-control cassette) that is carried on a suicide plasmid to enable insertion into the chromosome of the host. ACIT consists of multiple DNA fragments specifically arranged in a cassette that allows tight transcription control over any gene or gene cluster of interest following homologous recombination. At the heart of the invention is the ability to modify or exchange parts, e.g., promoters, to suit particular bacteria and growth conditions, allowing for customized gene expression control. Furthermore, ACIT provides a basis for a design-build-test approach for controlling gene expression in less studied bacteria. We describe examples of its control over pigment and exopolysaccharide production, growth, cell form, and social behavior in various Alphaproteobacteria.
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Affiliation(s)
- Jonas Kretz
- Institute of Microbiology and Molecular Biology, IFZ, Justus-Liebig-Universität, 35292 Giessen, Germany
| | - Vera Israel
- Institute of Microbiology and Molecular Biology, IFZ, Justus-Liebig-Universität, 35292 Giessen, Germany
| | - Matthew McIntosh
- Institute of Microbiology and Molecular Biology, IFZ, Justus-Liebig-Universität, 35292 Giessen, Germany
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15
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Chan DTC, Baldwin GS, Bernstein HC. Revealing the Host-Dependent Nature of an Engineered Genetic Inverter in Concordance with Physiology. BIODESIGN RESEARCH 2023; 5:0016. [PMID: 37849456 PMCID: PMC10432152 DOI: 10.34133/bdr.0016] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 07/17/2023] [Indexed: 10/19/2023] Open
Abstract
Broad-host-range synthetic biology is an emerging frontier that aims to expand our current engineerable domain of microbial hosts for biodesign applications. As more novel species are brought to "model status," synthetic biologists are discovering that identically engineered genetic circuits can exhibit different performances depending on the organism it operates within, an observation referred to as the "chassis effect." It remains a major challenge to uncover which genome-encoded and biological determinants will underpin chassis effects that govern the performance of engineered genetic devices. In this study, we compared model and novel bacterial hosts to ask whether phylogenomic relatedness or similarity in host physiology is a better predictor of genetic circuit performance. This was accomplished using a comparative framework based on multivariate statistical approaches to systematically demonstrate the chassis effect and characterize the performance dynamics of a genetic inverter circuit operating within 6 Gammaproteobacteria. Our results solidify the notion that genetic devices are strongly impacted by the host context. Furthermore, we formally determined that hosts exhibiting more similar metrics of growth and molecular physiology also exhibit more similar performance of the genetic inverter, indicating that specific bacterial physiology underpins measurable chassis effects. The result of this study contributes to the field of broad-host-range synthetic biology by lending increased predictive power to the implementation of genetic devices in less-established microbial hosts.
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Affiliation(s)
- Dennis Tin Chat Chan
- Faculty of Biosciences, Fisheries and Economics, UiT, The Arctic University of Norway, 9019 Tromsø, Norway
| | - Geoff S. Baldwin
- Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, UK
- Imperial College Centre for Synthetic Biology, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Hans C. Bernstein
- Faculty of Biosciences, Fisheries and Economics, UiT, The Arctic University of Norway, 9019 Tromsø, Norway
- The Arctic Centre for Sustainable Energy, UiT, The Arctic University of Norway, 9019 Tromsø, Norway
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16
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Esteves NC, Bigham DN, Scharf BE. Phages on filaments: A genetic screen elucidates the complex interactions between Salmonella enterica flagellin and bacteriophage Chi. PLoS Pathog 2023; 19:e1011537. [PMID: 37535496 PMCID: PMC10399903 DOI: 10.1371/journal.ppat.1011537] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 07/04/2023] [Indexed: 08/05/2023] Open
Abstract
The bacterial flagellum is a rotary motor organelle and important virulence factor that propels motile pathogenic bacteria, such as Salmonella enterica, through their surroundings. Bacteriophages, or phages, are viruses that solely infect bacteria. As such, phages have myriad applications in the healthcare field, including phage therapy against antibiotic-resistant bacterial pathogens. Bacteriophage χ (Chi) is a flagellum-dependent (flagellotropic) bacteriophage, which begins its infection cycle by attaching its long tail fiber to the S. enterica flagellar filament as its primary receptor. The interactions between phage and flagellum are poorly understood, as are the reasons that χ only kills certain Salmonella serotypes while others entirely evade phage infection. In this study, we used molecular cloning, targeted mutagenesis, heterologous flagellin expression, and phage-host interaction assays to determine which domains within the flagellar filament protein flagellin mediate this complex interaction. We identified the antigenic N- and C-terminal D2 domains as essential for phage χ binding, with the hypervariable central D3 domain playing a less crucial role. Here, we report that the primary structure of the Salmonella flagellin D2 domains is the major determinant of χ adhesion. The phage susceptibility of a strain is directly tied to these domains. We additionally uncovered important information about flagellar function. The central and most variable domain, D3, is not required for motility in S. Typhimurium 14028s, as it can be deleted or its sequence composition can be significantly altered with minimal impacts on motility. Further knowledge about the complex interactions between flagellotropic phage χ and its primary bacterial receptor may allow genetic engineering of its host range for use as targeted antimicrobial therapy against motile pathogens of the χ-host genera Salmonella, Escherichia, or Serratia.
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Affiliation(s)
- Nathaniel C. Esteves
- Dept. of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Danielle N. Bigham
- Dept. of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Birgit E. Scharf
- Dept. of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
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17
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Martinusen SG, Slaton EW, Nelson SE, Pulgar MA, Besu JT, Simas CF, Denard CA. Modular and integrative activity reporters enhance biochemical studies in the yeast ER. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.12.548713. [PMID: 37502857 PMCID: PMC10369952 DOI: 10.1101/2023.07.12.548713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
The yeast endoplasmic reticulum sequestration and screening (YESS) system is a generalizable platform that has become highly useful to investigate post-translational modification enzymes (PTM-enzymes). This system enables researchers to profile and engineer the activity and substrate specificity of PTM-enzymes and to discover inhibitor-resistant enzyme mutants. In this study, we expand the capabilities of YESS by transferring its functional components to integrative plasmids. The YESS integrative system yields uniform protein expression and protease activities in various configurations, allows one to integrate activity reporters at two independent loci and to split the system between integrative and centromeric plasmids. We characterize these integrative reporters with two viral proteases, Tobacco etch virus (TEVp) and 3-chymotrypsin like protease (3CL pro ), in terms of coefficient of variance, signal-to-noise ratio and fold-activation. Overall, we provide a framework for chromosomal-based studies that is modular, enabling rigorous high-throughput assays of PTM-enzymes in yeast.
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18
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Esson R, Falque S, Abachin E, George S, Nougarede N. Development of a droplet digital PCR for pertussis toxin locus copy number determination in a genetically-modified Bordetella pertussis strain. Biologicals 2023; 82:101683. [PMID: 37149976 DOI: 10.1016/j.biologicals.2023.101683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 02/21/2023] [Accepted: 04/24/2023] [Indexed: 05/09/2023] Open
Abstract
To improve pertussis toxin (PT) yield in B. pertussis strains for vaccine production a genetically-engineered strain (gdPT 191-134 strain) with a second copy of the genetically detoxified PT (gdPT) locus was developed. The consistency of the production and genetic stability of the strain when used for vaccine production must be established. We developed two simplex ddPCR assays with PCR systems for ptxA, the target gene present in two copies, and pgm, the reference gene present as a single copy. The ddPCR assay had sufficient precision to discriminate the copy number of the PT locus accurately in two B. pertussis strains: one copy in the parent, non-genetically-engineered strain and two copies in the gdPT 191-134 strain. Using the ddPCR assays, we were able to show that the ratio of the ptxA to pgm genes decreased during serial culture passages, due to the loss of PT locus, which in turn, resulted in lower levels of PT production over time. We were then able to assess culture conditions that improved the stability of the double locus, as shown by non-significant reduction in gdPT toxin yield.
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Affiliation(s)
- Raphaël Esson
- Analytical Sciences Department, Sanofi Pasteur - Campus Mérieux, 1541 Avenue Marcel Merieux, 69280, Marcy L'Etoile, France.
| | - Stéphanie Falque
- Analytical Sciences Department, Sanofi Pasteur - Campus Mérieux, 1541 Avenue Marcel Merieux, 69280, Marcy L'Etoile, France.
| | - Eric Abachin
- Analytical Sciences Department, Sanofi Pasteur - Campus Mérieux, 1541 Avenue Marcel Merieux, 69280, Marcy L'Etoile, France.
| | - Steve George
- Bioprocess Research & Development, Sanofi Pasteur, 1755 Steeles Ave West, Toronto, Ontario, M2R 3T4, Canada.
| | - Nolwenn Nougarede
- Analytical Sciences Department, Sanofi Pasteur - Campus Mérieux, 1541 Avenue Marcel Merieux, 69280, Marcy L'Etoile, France.
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19
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de Siqueira GMV, Guazzaroni ME. Host-Dependent Improvement of GFP Expression in Pseudomonas putida KT2440 Using Terminators of Metagenomic Origin. ACS Synth Biol 2023; 12:1562-1566. [PMID: 37126733 DOI: 10.1021/acssynbio.3c00098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Transcriptional terminators are key players in the flow of genetic information, but are often overlooked in circuit design. In this work, we used the Standard European Vector Architecture (SEVA) as a scaffold to investigate the effects of different terminators in the output of a reporter construct expressed in two bacterial species, and found that replacing the conventional T1 and T0 transcriptional terminators of the SEVA vector format with a set of broad-host metagenomic terminators resulted in a significant improvement in the signal of a fluorescent device in Pseudomonas putida KT2440 but not in Escherichia coli DH10B. Our results suggest that replacing the default set of terminators present in the SEVA specification may be an useful strategy for fine-tuning circuit expression in P. putida, which can be leveraged for the development of new devices with improved performance in this microbial host.
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Affiliation(s)
| | - María-Eugenia Guazzaroni
- Department of Biology, Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo, Ribeirao Preto 14040-901, Brazil
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20
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Li X, Bao N, Yan Z, Yuan XZ, Wang SG, Xia PF. Degradation of Antibiotic Resistance Genes by VADER with CRISPR-Cas Immunity. Appl Environ Microbiol 2023; 89:e0005323. [PMID: 36975789 PMCID: PMC10132114 DOI: 10.1128/aem.00053-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 03/03/2023] [Indexed: 03/29/2023] Open
Abstract
The evolution and dissemination of antibiotic resistance genes (ARGs) are prompting severe health and environmental issues. While environmental processes, e.g., biological wastewater treatment, are key barriers to prevent the spread of ARGs, they are often sources of ARGs at the same time, requiring upgraded biotechnology. Here, we present VADER, a synthetic biology system for the degradation of ARGs based on CRISPR-Cas immunity, an archaeal and bacterial immune system for eliminating invading foreign DNAs, to be implemented for wastewater treatment processes. Navigated by programmable guide RNAs, VADER targets and degrades ARGs depending on their DNA sequences, and by employing an artificial conjugation machinery, IncP, it can be delivered via conjugation. The system was evaluated by degrading plasmid-borne ARGs in Escherichia coli and further demonstrated via the elimination of ARGs on the environmentally relevant RP4 plasmid in Pseudomonas aeruginosa. Next, a prototype conjugation reactor at a 10-mL scale was devised, and 100% of the target ARG was eliminated in the transconjugants receiving VADER, giving a proof of principle for the implementation of VADER in bioprocesses. By generating a nexus of synthetic biology and environmental biotechnology, we believe that our work is not only an enterprise for tackling ARG problems but also a potential solution for managing undesired genetic materials in general in the future. IMPORTANCE Antibiotic resistance has been causing severe health problems and has led to millions of deaths in recent years. Environmental processes, especially those of the wastewater treatment sector, are an important barrier to the spread of antibiotic resistance from the pharmaceutical industry, hospitals, or civil sewage. However, they have been identified as a nonnegligible source of antibiotic resistance at the same time, as antibiotic resistance with its main cause, antibiotic resistance genes (ARGs), may accumulate in biological treatment units. Here, we transplanted the CRISPR-Cas system, an immune system via programmable DNA cleavage, to tackle the antibiotic resistance problem raised in wastewater treatment processes, and we propose a new sector specialized in ARG removal with a conjugation reactor to implement the CRISPR-Cas system. Our study provides a new angle for resolving public health issues via the implementation of synthetic biology in environmental contexts at the process level.
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Affiliation(s)
- Xin Li
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, China
| | - Nan Bao
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, China
| | - Zhen Yan
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, China
| | - Xian-Zheng Yuan
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, China
- Sino-French Research Institute for Ecology and Environment, Shandong University, Qingdao, China
| | - Shu-Guang Wang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, China
- Sino-French Research Institute for Ecology and Environment, Shandong University, Qingdao, China
| | - Peng-Fei Xia
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, China
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21
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Pasotti L, De Marchi D, Casanova M, Frusteri Chiacchiera A, Cusella De Angelis MG, Calvio C, Magni P. Design of a stable ethanologenic bacterial strain without heterologous plasmids and antibiotic resistance genes for efficient ethanol production from concentrated dairy waste. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:57. [PMID: 37005680 PMCID: PMC10067303 DOI: 10.1186/s13068-023-02298-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 03/03/2023] [Indexed: 04/04/2023]
Abstract
Engineering sustainable bioprocesses that convert abundant waste into fuels is pivotal for efficient production of renewable energy. We previously engineered an Escherichia coli strain for optimized bioethanol production from lactose-rich wastewater like concentrated whey permeate (CWP), a dairy effluent obtained from whey valorization processes. Although attractive fermentation performances were reached, significant improvements are required to eliminate recombinant plasmids, antibiotic resistances and inducible promoters, and increase ethanol tolerance. Here, we report a new strain with chromosomally integrated ethanologenic pathway under the control of a constitutive promoter, without recombinant plasmids and resistance genes. The strain showed extreme stability in 1-month subculturing, with CWP fermentation performances similar to the ethanologenic plasmid-bearing strain. We then investigated conditions enabling efficient ethanol production and sugar consumption by changing inoculum size and CWP concentration, revealing toxicity- and nutritional-related bottlenecks. The joint increase of ethanol tolerance, via adaptive evolution, and supplementation of small ammonium sulphate amounts (0.05% w/v) enabled a fermentation boost with 6.6% v/v ethanol titer, 1.2 g/L/h rate, 82.5% yield, and cell viability increased by three orders of magnitude. Our strain has attractive features for industrial settings and represents a relevant improvement in the existing ethanol production biotechnologies.
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Affiliation(s)
- Lorenzo Pasotti
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Via Ferrata 5, 27100, Pavia, Italy.
- Centre for Health Technologies, University of Pavia, Via Ferrata 5, 27100, Pavia, Italy.
| | - Davide De Marchi
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Via Ferrata 5, 27100, Pavia, Italy
- Centre for Health Technologies, University of Pavia, Via Ferrata 5, 27100, Pavia, Italy
| | - Michela Casanova
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Via Ferrata 5, 27100, Pavia, Italy
- Centre for Health Technologies, University of Pavia, Via Ferrata 5, 27100, Pavia, Italy
| | - Angelica Frusteri Chiacchiera
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Via Ferrata 5, 27100, Pavia, Italy
- Centre for Health Technologies, University of Pavia, Via Ferrata 5, 27100, Pavia, Italy
| | - Maria Gabriella Cusella De Angelis
- Centre for Health Technologies, University of Pavia, Via Ferrata 5, 27100, Pavia, Italy
- Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Via Forlanini 8, 27100, Pavia, Italy
| | - Cinzia Calvio
- Centre for Health Technologies, University of Pavia, Via Ferrata 5, 27100, Pavia, Italy
- Department of Biology and Biotechnology, University of Pavia, Via Ferrata 9, 27100, Pavia, Italy
| | - Paolo Magni
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Via Ferrata 5, 27100, Pavia, Italy
- Centre for Health Technologies, University of Pavia, Via Ferrata 5, 27100, Pavia, Italy
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Calvanese M, Balestra C, Colarusso A, Lauro C, Riccardi C, Fondi M, Parrilli E, Tutino ML. Development of high-copy number plasmids in Pseudoalteromonas haloplanktis TAC125. Appl Microbiol Biotechnol 2023; 107:2469-2481. [PMID: 36912903 PMCID: PMC10033558 DOI: 10.1007/s00253-023-12448-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 01/23/2023] [Accepted: 02/21/2023] [Indexed: 03/14/2023]
Abstract
The Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 (PhTAC125) is considered an interesting alternative host for the recombinant protein production, that can be explored when the conventional bacterial expression systems fail. Indeed, the manufacture of all the difficult-to-express proteins produced so far in this bacterial platform gave back soluble and active products. Despite these promising results, the low yield of recombinant protein production achieved is hampering the wider and industrial exploitation of this psychrophilic cell factory. All the expression plasmids developed so far in PhTAC125 are based on the origin of replication of the endogenous pMtBL plasmid and are maintained at a very low copy number. In this work, we set up an experimental strategy to select mutated OriR sequences endowed with the ability to establish recombinant plasmids at higher multiplicity per cell. The solution to this major production bottleneck was achieved by the construction of a library of psychrophilic vectors, each containing a randomly mutated version of pMtBL OriR, and its screening by fluorescence-activated cell sorting (FACS). The selected clones allowed the identification of mutated OriR sequences effective in enhancing the plasmid copy number of approximately two orders of magnitude, and the production of the recombinant green fluorescent protein was increased up to twenty times approximately. Moreover, the molecular characterization of the different mutant OriR sequences allowed us to suggest some preliminary clues on the pMtBL replication mechanism that deserve to be further investigated in the future. KEY POINTS: • Setup of an electroporation procedure for Pseudoalteromonas haloplanktis TAC125. • Two order of magnitude improvement of OriR-derived psychrophilic expression systems. • Almost twenty times enhancement in Green fluorescent protein production.
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Affiliation(s)
- Marzia Calvanese
- Department of Chemical Sciences, Federico II University of Naples, Complesso Universitario Monte S.- Angelo, Via Cintia, 80126, Naples, Italy
| | - Cecilia Balestra
- Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Oceanography Division - OGS, Trieste, Italy
| | - Andrea Colarusso
- Department of Chemical Sciences, Federico II University of Naples, Complesso Universitario Monte S.- Angelo, Via Cintia, 80126, Naples, Italy
- Istituto Nazionale Biostrutture e Biosistemi I.N.B.B, Viale Medaglie d'Oro, 305-00136, Rome, Italy
| | - Concetta Lauro
- Department of Chemical Sciences, Federico II University of Naples, Complesso Universitario Monte S.- Angelo, Via Cintia, 80126, Naples, Italy
- Istituto Nazionale Biostrutture e Biosistemi I.N.B.B, Viale Medaglie d'Oro, 305-00136, Rome, Italy
| | - Christopher Riccardi
- Department of Biology, Via Madonna del Piano 6, Sesto Fiorentino, 50018, Florence, Italy
| | - Marco Fondi
- Department of Biology, Via Madonna del Piano 6, Sesto Fiorentino, 50018, Florence, Italy
| | - Ermenegilda Parrilli
- Department of Chemical Sciences, Federico II University of Naples, Complesso Universitario Monte S.- Angelo, Via Cintia, 80126, Naples, Italy
| | - Maria Luisa Tutino
- Department of Chemical Sciences, Federico II University of Naples, Complesso Universitario Monte S.- Angelo, Via Cintia, 80126, Naples, Italy.
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23
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Singh B, Kumar A, Saini AK, Saini RV, Thakur R, Mohammed SA, Tuli HS, Gupta VK, Areeshi MY, Faidah H, Jalal NA, Haque S. Strengthening microbial cell factories for efficient production of bioactive molecules. Biotechnol Genet Eng Rev 2023:1-34. [PMID: 36809927 DOI: 10.1080/02648725.2023.2177039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 01/21/2023] [Indexed: 02/24/2023]
Abstract
High demand of bioactive molecules (food additives, antibiotics, plant growth enhancers, cosmetics, pigments and other commercial products) is the prime need for the betterment of human life where the applicability of the synthetic chemical product is on the saturation due to associated toxicity and ornamentations. It has been noticed that the discovery and productivity of such molecules in natural scenarios are limited due to low cellular yields as well as less optimized conventional methods. In this respect, microbial cell factories timely fulfilling the requirement of synthesizing bioactive molecules by improving production yield and screening more promising structural homologues of the native molecule. Where the robustness of the microbial host can be potentially achieved by taking advantage of cell engineering approaches such as tuning functional and adjustable factors, metabolic balancing, adapting cellular transcription machinery, applying high throughput OMICs tools, stability of genotype/phenotype, organelle optimizations, genome editing (CRISPER/Cas mediated system) and also by developing accurate model systems via machine-learning tools. In this article, we provide an overview from traditional to recent trends and the application of newly developed technologies, for strengthening the systemic approaches and providing future directions for enhancing the robustness of microbial cell factories to speed up the production of biomolecules for commercial purposes.
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Affiliation(s)
- Bharat Singh
- Department of Biotechnology and Central Research Cell, MMEC, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, India
| | - Ankit Kumar
- TERI-Deakin Nanobiotechnology Centre, TERI Gram, The Energy and Resources Institute, Gurugram, India
| | - Adesh Kumar Saini
- Department of Biotechnology and Central Research Cell, MMEC, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, India
| | - Reena Vohra Saini
- Department of Biotechnology and Central Research Cell, MMEC, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, India
| | - Rahul Thakur
- Department of Biotechnology and Central Research Cell, MMEC, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, India
| | - Shakeel A Mohammed
- Department of Biotechnology and Central Research Cell, MMEC, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, India
| | - Hardeep Singh Tuli
- Department of Biotechnology and Central Research Cell, MMEC, Maharishi Markandeshwar (Deemed to be University), Mullana-Ambala, India
| | - Vijai Kumar Gupta
- Biorefining and Advanced Materials Research Centre, Scotland's Rural College (SRUC), Edinburgh, UK
| | - Mohammed Y Areeshi
- Medical Laboratory Technology Department, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan, Saudi Arabia
| | - Hani Faidah
- Department of Microbiology, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Naif A Jalal
- Department of Microbiology, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Shafiul Haque
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan, Saudi Arabia
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Beirut, Lebanon
- Centre of Medical and Bio-Allied Health Sciences Research, Ajman University, Ajman, United Arab Emirates
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24
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Davray D, Bawane H, Kulkarni R. Non-redundant nature of Lactiplantibacillus plantarum plasmidome revealed by comparative genomic analysis of 105 strains. Food Microbiol 2023; 109:104153. [DOI: 10.1016/j.fm.2022.104153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 09/09/2022] [Accepted: 09/21/2022] [Indexed: 11/16/2022]
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25
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Kirillov A, Morozova N, Kozlova S, Polinovskaya V, Smirnov S, Khodorkovskii M, Zeng L, Ispolatov Y, Severinov K. Cells with stochastically increased methyltransferase to restriction endonuclease ratio provide an entry for bacteriophage into protected cell population. Nucleic Acids Res 2022; 50:12355-12368. [PMID: 36477901 PMCID: PMC9757035 DOI: 10.1093/nar/gkac1124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 10/29/2022] [Accepted: 11/14/2022] [Indexed: 12/13/2022] Open
Abstract
The action of Type II restriction-modification (RM) systems depends on restriction endonuclease (REase), which cleaves foreign DNA at specific sites, and methyltransferase (MTase), which protects host genome from restriction by methylating the same sites. We here show that protection from phage infection increases as the copy number of plasmids carrying the Type II RM Esp1396I system is increased. However, since increased plasmid copy number leads to both increased absolute intracellular RM enzyme levels and to a decreased MTase/REase ratio, it is impossible to determine which factor determines resistance/susceptibility to infection. By controlled expression of individual Esp1396I MTase or REase genes in cells carrying the Esp1396I system, we show that a shift in the MTase to REase ratio caused by overproduction of MTase or REase leads, respectively, to decreased or increased protection from infection. Consistently, due to stochastic variation of MTase and REase amount in individual cells, bacterial cells that are productively infected by bacteriophage have significantly higher MTase to REase ratios than cells that ward off the infection. Our results suggest that cells with transiently increased MTase to REase ratio at the time of infection serve as entry points for unmodified phage DNA into protected bacterial populations.
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Affiliation(s)
- Alexander Kirillov
- Skolkovo Institute of Science and Technology, Center for Molecular and Cellular Biology, Moscow 121205, Russia,Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia
| | - Natalia Morozova
- Skolkovo Institute of Science and Technology, Center for Molecular and Cellular Biology, Moscow 121205, Russia,Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia
| | - Svetlana Kozlova
- Skolkovo Institute of Science and Technology, Center for Molecular and Cellular Biology, Moscow 121205, Russia
| | - Vasilisa Polinovskaya
- Skolkovo Institute of Science and Technology, Center for Molecular and Cellular Biology, Moscow 121205, Russia
| | - Sergey Smirnov
- Skolkovo Institute of Science and Technology, Center for Molecular and Cellular Biology, Moscow 121205, Russia
| | - Mikhail Khodorkovskii
- Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russia
| | - Lanying Zeng
- Texas A&M University, Department of Biochemistry and Biophysics, Center for Phage Technology, College Station, TX 77843, USA
| | - Yaroslav Ispolatov
- University of Santiago of Chile (USACH), Physics Department, Av. Víctor Jara 3493, Santiago, Chile
| | - Konstantin Severinov
- To whom correspondence should be addressed. Tel: +7 9854570284; Fax: +1 848 445 5735;
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26
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Hernandez‐Beltran JCR, Miró Pina V, Siri‐Jégousse A, Palau S, Peña‐Miller R, González Casanova A. Segregational instability of multicopy plasmids: A population genetics approach. Ecol Evol 2022; 12:e9469. [PMID: 36479025 PMCID: PMC9720003 DOI: 10.1002/ece3.9469] [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: 10/07/2022] [Accepted: 10/14/2022] [Indexed: 12/11/2022] Open
Abstract
Plasmids are extra-chromosomal genetic elements that encode a wide variety of phenotypes and can be maintained in bacterial populations through vertical and horizontal transmission, thus increasing bacterial adaptation to hostile environmental conditions like those imposed by antimicrobial substances. To circumvent the segregational instability resulting from randomly distributing plasmids between daughter cells upon division, nontransmissible plasmids tend to be carried in multiple copies per cell, with the added benefit of exhibiting increased gene dosage and resistance levels. But carrying multiple copies also results in a high metabolic burden to the bacterial host, therefore reducing the overall fitness of the population. This trade-off poses an existential question for plasmids: What is the optimal plasmid copy number? In this manuscript, we address this question by postulating and analyzing a population genetics model to evaluate the interaction between selective pressure, the number of plasmid copies carried by each cell, and the metabolic burden associated with plasmid bearing in the absence of selection for plasmid-encoded traits. Parameter values of the model were estimated experimentally using Escherichia coli K12 carrying a multicopy plasmid encoding for a fluorescent protein and bla TEM-1, a gene conferring resistance to β-lactam antibiotics. By numerically determining the optimal plasmid copy number for constant and fluctuating selection regimes, we show that plasmid copy number is a highly optimized evolutionary trait that depends on the rate of environmental fluctuation and balances the benefit between increased stability in the absence of selection with the burden associated with carrying multiple copies of the plasmid.
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Affiliation(s)
- J. Carlos R. Hernandez‐Beltran
- Systems Biology Program, Center for Genomic SciencesUniversidad Nacional Autónoma de MéxicoCuernavacaMexico,Department of Microbial Population BiologyMax Planck Institute for Evolutionary BiologyPlönGermany
| | - Verónica Miró Pina
- Centre for Genomic Regulation (CRG)The Barcelona Institute of Science and TechnologyBarcelonaSpain,Universitat Pompeu Fabra (UPF)BarcelonaSpain,Departamento de Probabilidad y Estadística, Instituto de Investigación en Matemáticas Aplicadas y en SistemasUniversidad Nacional Autónoma de MéxicoCuernavacaMexico
| | - Arno Siri‐Jégousse
- Departamento de Probabilidad y Estadística, Instituto de Investigación en Matemáticas Aplicadas y en SistemasUniversidad Nacional Autónoma de MéxicoCuernavacaMexico
| | - Sandra Palau
- Departamento de Probabilidad y Estadística, Instituto de Investigación en Matemáticas Aplicadas y en SistemasUniversidad Nacional Autónoma de MéxicoCuernavacaMexico
| | - Rafael Peña‐Miller
- Systems Biology Program, Center for Genomic SciencesUniversidad Nacional Autónoma de MéxicoCuernavacaMexico
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27
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Zhang Y, Bailey TS, Kubiak AM, Lambin P, Theys J. Heterologous Gene Regulation in Clostridia: Rationally Designed Gene Regulation for Industrial and Medical Applications. ACS Synth Biol 2022; 11:3817-3828. [PMID: 36265075 PMCID: PMC9680021 DOI: 10.1021/acssynbio.2c00401] [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] [Indexed: 01/27/2023]
Abstract
Several species from the Clostridium genus show promise as industrial solvent producers and cancer therapeutic delivery vehicles. Previous development of shuttle plasmids and genome editing tools has aided the study of these species and enabled their exploitation in industrial and medical applications. Nevertheless, the precise control of gene expression is still hindered by the limited range of characterized promoters. To address this, libraries of promoters (native and synthetic), 5' UTRs, and alternative start codons were constructed. These constructs were tested in Escherichia coli K-12, Clostridium sporogenes NCIMB 10696, and Clostridium butyricum DSM 10702, using β-glucuronidase (gusA) as a gene reporter. Promoter activity was corroborated using a second gene reporter, nitroreductase (nmeNTR) from Neisseria meningitides. A strong correlation was observed between the two reporters. In C. sporogenes and C. butyricum, respectively, changes in GusA activity between the weakest and strongest expressing levels were 129-fold and 78-fold. Similar results were obtained with the nmeNTR. Using the GusA reporter, translation initiation from six alternative (non-AUG) start codons was measured in E. coli, C. sporogenes, and C. butyricum. Clearly, species-specific differences between clostridia and E. coli in translation initiation were observed, and the performance of the start codons was influenced by the upstream 5' UTR sequence. These results highlight a new opportunity for gene control in recombinant clostridia. To demonstrate the value of these results, expression of the sacB gene from Bacillus subtilis was optimized for use as a novel negative selection marker in C. butyricum. In summary, these results indicate improvements in the understanding of heterologous gene regulation in Clostridium species and E. coli cloning strains. This new knowledge can be utilized for rationally designed gene regulation in Clostridium-mediated industrial and medical applications, as well as fundamental research into the biology of Clostridium species.
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Affiliation(s)
- Yanchao Zhang
- The
M-Lab, Department of Precision Medicine, GROW - School of Oncology
and Reproduction, Maastricht University, 6229 ER Maastricht, The Netherlands,
| | - Tom S. Bailey
- The
M-Lab, Department of Precision Medicine, GROW - School of Oncology
and Reproduction, Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Aleksandra M. Kubiak
- The
M-Lab, Department of Precision Medicine, GROW - School of Oncology
and Reproduction, Maastricht University, 6229 ER Maastricht, The Netherlands,Exomnis
Biotech BV, Oxfordlaan
55, 6229 EV Maastricht, The Netherlands
| | - Philippe Lambin
- The
M-Lab, Department of Precision Medicine, GROW - School of Oncology
and Reproduction, Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Jan Theys
- The
M-Lab, Department of Precision Medicine, GROW - School of Oncology
and Reproduction, Maastricht University, 6229 ER Maastricht, The Netherlands
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28
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Klanschnig M, Cserjan-Puschmann M, Striedner G, Grabherr R. CRISPRactivation-SMS, a message for PAM sequence independent gene up-regulation in Escherichia coli. Nucleic Acids Res 2022; 50:10772-10784. [PMID: 36134715 PMCID: PMC9561276 DOI: 10.1093/nar/gkac804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/10/2022] [Accepted: 09/08/2022] [Indexed: 12/26/2022] Open
Abstract
Governance of the endogenous gene regulatory network enables the navigation of cells towards beneficial traits for recombinant protein production. CRISPRactivation and interference provides the basis for gene expression modulation but is primarily applied in eukaryotes. Particularly the lack of wide-ranging prokaryotic CRISPRa studies might be attributed to intrinsic limitations of bacterial activators and Cas9 proteins. While bacterial activators need accurate spatial orientation and distancing towards the target promoter to be functional, Cas9-based CRISPR tools only bind sites adjacent to NGG PAM sequences. These circumstances hampered Cas9-guided activators from mediating the up-regulation of endogenous genes at precise positions in bacteria. We could overcome this limitation by combining the PAM independent Cas9 variant SpRY and a CRISPRa construct using phage protein MCP fused to transcriptional activator SoxS. This CRISPRa construct, referred to as SMS, was compared with previously reported CRISPRa constructs and showed up-regulation of a reporter gene library independent of its PAM sequence in Escherichia coli. We also demonstrated down-regulation and multi-gene expression control with SMS at non-NGG PAM sites. Furthermore, we successfully applied SMS to up-regulate endogenous genes, and transgenes at non-NGG PAM sites, which was impossible with the previous CRISPRa construct.
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Affiliation(s)
- Marco Klanschnig
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, 1190 Vienna, Austria
| | - Monika Cserjan-Puschmann
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, 1190 Vienna, Austria
| | - Gerald Striedner
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, 1190 Vienna, Austria
| | - Reingard Grabherr
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, 1190 Vienna, Austria
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29
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Xia M, Zhuo N, Ren S, Zhang H, Yang Y, Lei L, Hu T. Enterococcus faecalis rnc gene modulates its susceptibility to disinfection agents: a novel approach against biofilm. BMC Oral Health 2022; 22:416. [PMID: 36127648 PMCID: PMC9490916 DOI: 10.1186/s12903-022-02462-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 09/12/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Enterococcus faecalis (E. faecalis) plays an important role in the failure of root canal treatment and refractory periapical periodontitis. As an important virulence factor of E. faecalis, extracellular polysaccharide (EPS) serves as a matrix to wrap bacteria and form biofilms. The homologous rnc gene, encoding Ribonuclease III, has been reported as a regulator of EPS synthesis. In order to develop novel anti-biofilm targets, we investigated the effects of the rnc gene on the biological characteristics of E. faecalis, and compared the biofilm tolerance towards the typical root canal irrigation agents and traditional Chinese medicine fluid Pudilan. METHODS E. faecalis rnc gene overexpression (rnc+) and low-expression (rnc-) strains were constructed. The growth curves of E. faecalis ATCC29212, rnc+, and rnc- strains were obtained to study the regulatory effect of the rnc gene on E. faecalis. Scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and crystal violet staining assays were performed to evaluate the morphology and composition of E. faecalis biofilms. Furthermore, the wild-type and mutant biofilms were treated with 5% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and Pudilan. The residual viabilities of E. faecalis biofilms were evaluated using crystal violet staining and colony counting assays. RESULTS The results demonstrated that the rnc gene could promote bacterial growth and EPS synthesis, causing the EPS-barren biofilm morphology and low EPS/bacteria ratio. Both the rnc+ and rnc- biofilms showed increased susceptibility to the root canal irrigation agents. The 5% NaOCl group showed the highest biofilm removing effect followed by Pudilan and 2% CHX. The colony counting results showed almost complete removal of bacteria in the 5% NaOCl, 2% CHX, and Chinese medicine agents' groups. CONCLUSIONS This study concluded that the rnc gene could positively regulate bacterial proliferation, EPS synthesis, and biofilm formation in E. faecalis. The rnc mutation caused an increase in the disinfectant sensitivity of biofilm, indicating a potential anti-biofilm target. In addition, Pudilan exhibited an excellent ability to remove E. faecalis biofilm.
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Affiliation(s)
- Mengying Xia
- Department of Preventive Dentistry, West China Hospital of Stomatology, Key Laboratory of Oral Diseases, Sichuan University, NO. 14 Third Section Renmin South Road, Chengdu, China
| | - Niya Zhuo
- Department of Preventive Dentistry, West China Hospital of Stomatology, Key Laboratory of Oral Diseases, Sichuan University, NO. 14 Third Section Renmin South Road, Chengdu, China
| | - Shirui Ren
- Department of Preventive Dentistry, West China Hospital of Stomatology, Key Laboratory of Oral Diseases, Sichuan University, NO. 14 Third Section Renmin South Road, Chengdu, China
| | - Hongyu Zhang
- Department of Preventive Dentistry, West China Hospital of Stomatology, Key Laboratory of Oral Diseases, Sichuan University, NO. 14 Third Section Renmin South Road, Chengdu, China
| | - Yingming Yang
- Department of Preventive Dentistry, West China Hospital of Stomatology, Key Laboratory of Oral Diseases, Sichuan University, NO. 14 Third Section Renmin South Road, Chengdu, China.
| | - Lei Lei
- Department of Preventive Dentistry, West China Hospital of Stomatology, Key Laboratory of Oral Diseases, Sichuan University, NO. 14 Third Section Renmin South Road, Chengdu, China.
| | - Tao Hu
- Department of Preventive Dentistry, West China Hospital of Stomatology, Key Laboratory of Oral Diseases, Sichuan University, NO. 14 Third Section Renmin South Road, Chengdu, China
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30
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Bobonis J, Mitosch K, Mateus A, Karcher N, Kritikos G, Selkrig J, Zietek M, Monzon V, Pfalz B, Garcia-Santamarina S, Galardini M, Sueki A, Kobayashi C, Stein F, Bateman A, Zeller G, Savitski MM, Elfenbein JR, Andrews-Polymenis HL, Typas A. Bacterial retrons encode phage-defending tripartite toxin-antitoxin systems. Nature 2022; 609:144-150. [PMID: 35850148 DOI: 10.1038/s41586-022-05091-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 07/08/2022] [Indexed: 11/09/2022]
Abstract
Retrons are prokaryotic genetic retroelements encoding a reverse transcriptase that produces multi-copy single-stranded DNA1 (msDNA). Despite decades of research on the biosynthesis of msDNA2, the function and physiological roles of retrons have remained unknown. Here we show that Retron-Sen2 of Salmonella enterica serovar Typhimurium encodes an accessory toxin protein, STM14_4640, which we renamed as RcaT. RcaT is neutralized by the reverse transcriptase-msDNA antitoxin complex, and becomes active upon perturbation of msDNA biosynthesis. The reverse transcriptase is required for binding to RcaT, and the msDNA is required for the antitoxin activity. The highly prevalent RcaT-containing retron family constitutes a new type of tripartite DNA-containing toxin-antitoxin system. To understand the physiological roles of such toxin-antitoxin systems, we developed toxin activation-inhibition conjugation (TAC-TIC), a high-throughput reverse genetics approach that identifies the molecular triggers and blockers of toxin-antitoxin systems. By applying TAC-TIC to Retron-Sen2, we identified multiple trigger and blocker proteins of phage origin. We demonstrate that phage-related triggers directly modify the msDNA, thereby activating RcaT and inhibiting bacterial growth. By contrast, prophage proteins circumvent retrons by directly blocking RcaT. Consistently, retron toxin-antitoxin systems act as abortive infection anti-phage defence systems, in line with recent reports3,4. Thus, RcaT retrons are tripartite DNA-regulated toxin-antitoxin systems, which use the reverse transcriptase-msDNA complex both as an antitoxin and as a sensor of phage protein activities.
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Affiliation(s)
- Jacob Bobonis
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Karin Mitosch
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - André Mateus
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå, Sweden
| | - Nicolai Karcher
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - George Kritikos
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Joel Selkrig
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Matylda Zietek
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Vivian Monzon
- European Bioinformatics Institute, European Molecular Biology Laboratory, Hinxton, UK
| | - Birgit Pfalz
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Sarela Garcia-Santamarina
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Institute of Chemical and Biological Technology António Xavier, Oeiras, Portugal
| | - Marco Galardini
- Institute for Molecular Bacteriology, TWINCORE Centre for Experimental and Clinical Infection Research, a joint venture between the Hannover Medical School (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Anna Sueki
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Biozentrum, University of Basel, Basel, Switzerland
| | - Callie Kobayashi
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College Station, TX, USA
| | - Frank Stein
- Proteomics Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Alex Bateman
- European Bioinformatics Institute, European Molecular Biology Laboratory, Hinxton, UK
| | - Georg Zeller
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Mikhail M Savitski
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Proteomics Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Johanna R Elfenbein
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA.
| | | | - Athanasios Typas
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
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31
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Otoničar J, Hostnik M, Grundner M, Kostanjšek R, Gredar T, Garvas M, Arsov Z, Podlesek Z, Gostinčar C, Jakše J, Busby SJW, Butala M. A method for targeting a specified segment of DNA to a bacterial microorganelle. Nucleic Acids Res 2022; 50:e113. [PMID: 36029110 DOI: 10.1093/nar/gkac714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 07/28/2022] [Accepted: 08/09/2022] [Indexed: 11/14/2022] Open
Abstract
Encapsulation of a selected DNA molecule in a cell has important implications for bionanotechnology. Non-viral proteins that can be used as nucleic acid containers include proteinaceous subcellular bacterial microcompartments (MCPs) that self-assemble into a selectively permeable protein shell containing an enzymatic core. Here, we adapted a propanediol utilization (Pdu) MCP into a synthetic protein cage to package a specified DNA segment in vivo, thereby enabling subsequent affinity purification. To this end, we engineered the LacI transcription repressor to be routed, together with target DNA, into the lumen of a Strep-tagged Pdu shell. Sequencing of extracted DNA from the affinity-isolated MCPs shows that our strategy results in packaging of a DNA segment carrying multiple LacI binding sites, but not the flanking regions. Furthermore, we used LacI to drive the encapsulation of a DNA segment containing operators for LacI and for a second transcription factor.
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Affiliation(s)
- Jan Otoničar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Maja Hostnik
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Maja Grundner
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Rok Kostanjšek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Tajda Gredar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Maja Garvas
- Jožef Stefan Institute, Condensed Matter Physics Department, 1000 Ljubljana, Slovenia
| | - Zoran Arsov
- Jožef Stefan Institute, Condensed Matter Physics Department, 1000 Ljubljana, Slovenia
| | - Zdravko Podlesek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Cene Gostinčar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Jernej Jakše
- Department of Agronomy, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Stephen J W Busby
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Matej Butala
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
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Chaillou S, Stamou PE, Torres LL, Riesco AB, Hazelton W, Pinheiro VB. Directed evolution of colE1 plasmid replication compatibility: a fast tractable tunable model for investigating biological orthogonality. Nucleic Acids Res 2022; 50:9568-9579. [PMID: 36018798 PMCID: PMC9458437 DOI: 10.1093/nar/gkac682] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 06/02/2022] [Accepted: 08/03/2022] [Indexed: 12/24/2022] Open
Abstract
Plasmids of the ColE1 family are among the most frequently used in molecular biology. They were adopted early for many biotechnology applications, and as models to study plasmid biology. Their mechanism of replication is well understood, involving specific interactions between a plasmid encoded sense-antisense gene pair (RNAI and RNAII). Due to such mechanism, two plasmids with the same origin cannot be stably maintained in cells-a process known as incompatibility. While mutations in RNAI and RNAII can make colE1 more compatible, there has been no systematic effort to engineer new compatible colE1 origins, which could bypass technical design constraints for multi-plasmid applications. Here, we show that by diversifying loop regions in RNAI (and RNAII), it is possible to select new viable colE1 origins compatible with the wild-type one. We demonstrate that sequence divergence is not sufficient to enable compatibility and pairwise interactions are not an accurate guide for higher order interactions. We identify potential principles to engineer plasmid copy number independently from other regulatory strategies and we propose plasmid compatibility as a tractable model to study biological orthogonality.
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Affiliation(s)
| | | | - Leticia L Torres
- University College London, Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Ana B Riesco
- University College London, Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Warren Hazelton
- University College London, Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Vitor B Pinheiro
- To whom correspondence should be addressed. Tel: +32 16 330 257;
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Hartline CJ, Zhang F. The Growth Dependent Design Constraints of Transcription-Factor-Based Metabolite Biosensors. ACS Synth Biol 2022; 11:2247-2258. [PMID: 35700119 PMCID: PMC9994378 DOI: 10.1021/acssynbio.2c00143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Metabolite biosensors based on metabolite-responsive transcription factors are key synthetic biology components for sensing and precisely controlling cellular metabolism. Biosensors are often designed under laboratory conditions but are deployed in applications where cellular growth rate differs drastically from its initial characterization. Here we asked how growth rate impacts the minimum and maximum biosensor outputs and the dynamic range, which are key metrics of biosensor performance. Using LacI, TetR, and FadR-based biosensors in Escherichia coli as models, we find that the dynamic range of different biosensors have different growth rate dependencies. We developed a kinetic model to explore how tuning biosensor parameters impact the dynamic range growth rate dependence. Our modeling and experimental results revealed that the effects to dynamic range and its growth rate dependence are often coupled, and the metabolite transport mechanisms shape the dynamic range-growth rate response. This work provides a systematic understanding of biosensor performance under different growth rates, which will be useful for predicting biosensor behavior in broad synthetic biology and metabolic engineering applications.
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Affiliation(s)
- Christopher J Hartline
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missouri 63130, United States
| | - Fuzhong Zhang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missouri 63130, United States.,Division of Biology & Biomedical Sciences, Washington University in St. Louis, Saint Louis, Missouri 63130, United States.,Institute of Materials Science & Engineering, Washington University in St. Louis, Saint Louis, Missouri 63130, United States
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Abstract
Quorum sensing is described as a widespread cell density-dependent signaling mechanism in bacteria. Groups of cells coordinate gene expression by secreting and responding to diffusible signal molecules. Theory, however, predicts that individual cells may short-circuit this mechanism by directly responding to the signals they produce irrespective of cell density. In this study, we characterize this self-sensing effect in the acyl-homoserine lactone quorum sensing system of Pseudomonas aeruginosa. We show that antiactivators, a set of proteins known to affect signal sensitivity, function to prevent self-sensing. Measuring quorum-sensing gene expression in individual cells at very low densities, we find that successive deletion of antiactivator genes qteE and qslA produces a bimodal response pattern, in which increasing proportions of constitutively induced cells coexist with uninduced cells. Comparing responses of signal-proficient and -deficient cells in cocultures, we find that signal-proficient cells show a much higher response in the antiactivator mutant background but not in the wild-type background. Our results experimentally demonstrate the antiactivator-dependent transition from group- to self-sensing in the quorum-sensing circuitry of P. aeruginosa. Taken together, these findings extend our understanding of the functional capacity of quorum sensing. They highlight the functional significance of antiactivators in the maintenance of group-level signaling and experimentally prove long-standing theoretical predictions.
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35
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Brandenberg OF, Schubert OT, Kruglyak L. Towards synthetic PETtrophy: Engineering Pseudomonas putida for concurrent polyethylene terephthalate (PET) monomer metabolism and PET hydrolase expression. Microb Cell Fact 2022; 21:119. [PMID: 35717313 PMCID: PMC9206389 DOI: 10.1186/s12934-022-01849-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/26/2022] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Biocatalysis offers a promising path for plastic waste management and valorization, especially for hydrolysable plastics such as polyethylene terephthalate (PET). Microbial whole-cell biocatalysts for simultaneous PET degradation and growth on PET monomers would offer a one-step solution toward PET recycling or upcycling. We set out to engineer the industry-proven bacterium Pseudomonas putida for (i) metabolism of PET monomers as sole carbon sources, and (ii) efficient extracellular expression of PET hydrolases. We pursued this approach for both PET and the related polyester polybutylene adipate co-terephthalate (PBAT), aiming to learn about the determinants and potential applications of bacterial polyester-degrading biocatalysts. RESULTS P. putida was engineered to metabolize the PET and PBAT monomer terephthalic acid (TA) through genomic integration of four tphII operon genes from Comamonas sp. E6. Efficient cellular TA uptake was enabled by a point mutation in the native P. putida membrane transporter MhpT. Metabolism of the PET and PBAT monomers ethylene glycol and 1,4-butanediol was achieved through adaptive laboratory evolution. We then used fast design-build-test-learn cycles to engineer extracellular PET hydrolase expression, including tests of (i) the three PET hydrolases LCC, HiC, and IsPETase; (ii) genomic versus plasmid-based expression, using expression plasmids with high, medium, and low cellular copy number; (iii) three different promoter systems; (iv) three membrane anchor proteins for PET hydrolase cell surface display; and (v) a 30-mer signal peptide library for PET hydrolase secretion. PET hydrolase surface display and secretion was successfully engineered but often resulted in host cell fitness costs, which could be mitigated by promoter choice and altering construct copy number. Plastic biodegradation assays with the best PET hydrolase expression constructs genomically integrated into our monomer-metabolizing P. putida strains resulted in various degrees of plastic depolymerization, although self-sustaining bacterial growth remained elusive. CONCLUSION Our results show that balancing extracellular PET hydrolase expression with cellular fitness under nutrient-limiting conditions is a challenge. The precise knowledge of such bottlenecks, together with the vast array of PET hydrolase expression tools generated and tested here, may serve as a baseline for future efforts to engineer P. putida or other bacterial hosts towards becoming efficient whole-cell polyester-degrading biocatalysts.
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Affiliation(s)
- Oliver F Brandenberg
- Department of Human Genetics, Department of Biological Chemistry, and Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, USA.
| | - Olga T Schubert
- Department of Human Genetics, Department of Biological Chemistry, and Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, USA.,Department of Environmental Microbiology, EAWAG, 8600, Dübendorf, Switzerland.,Department of Environmental Systems Science, ETH Zurich, 8092, Zürich, Switzerland
| | - Leonid Kruglyak
- Department of Human Genetics, Department of Biological Chemistry, and Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, USA.
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Fernández-Cabezón L, Rosich I Bosch B, Kozaeva E, Gurdo N, Nikel PI. Dynamic flux regulation for high-titer anthranilate production by plasmid-free, conditionally-auxotrophic strains of Pseudomonas putida. Metab Eng 2022; 73:11-25. [PMID: 35659519 DOI: 10.1016/j.ymben.2022.05.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/05/2022] [Accepted: 05/29/2022] [Indexed: 10/18/2022]
Abstract
Anthranilate, an intermediate of the shikimate pathway, is a high-value aromatic compound widely used as a precursor in the production of dyes, fragrances, plastics and pharmaceuticals. Traditional strategies adopted for microbial anthranilate production rely on the implementation of auxotrophic strains-which requires aromatic amino acids or complex additives to be supplemented in the culture medium, negatively impacting production costs. In this work, we engineered the soil bacterium Pseudomonas putida for high-titer, glucose-dependent anthranilate production by repurposing elements of the Esa quorum sensing (QS) system of Pantoea stewartii. The PesaS promoter mediated a self-regulated transcriptional response that effectively knocked-down the expression of the trpDC genes. Next, we harnessed the synthetic QS elements to engineer a growth-to-anthranilate production switch. The resulting plasmid-free P. putida strain produced the target compound at 3.8 ± 0.3 mM in shaken-flask cultures after 72 h-a titer >2-fold higher than anthranilate levels reported thus far. Our results highlight the value of dynamic flux regulation for the production of intermediate metabolites within highly-regulated routes (such as the shikimate pathway), thereby circumventing the need of expensive additives.
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Affiliation(s)
- Lorena Fernández-Cabezón
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Berta Rosich I Bosch
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Ekaterina Kozaeva
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Nicolás Gurdo
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Pablo Iván Nikel
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark.
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Yue SJ, Huang P, Li S, Cai YY, Wang W, Zhang XH, Nikel PI, Hu HB. Developing a CRISPR-assisted base-editing system for genome engineering of Pseudomonas chlororaphis. Microb Biotechnol 2022; 15:2324-2336. [PMID: 35575623 PMCID: PMC9437888 DOI: 10.1111/1751-7915.14075] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/29/2022] [Accepted: 05/02/2022] [Indexed: 12/01/2022] Open
Abstract
Pseudomonas chlororaphis is a non‐pathogenic, plant growth‐promoting rhizobacterium that secretes phenazine compounds with broad‐spectrum antibiotic activity. Currently available genome‐editing methods for P. chlororaphis are based on homologous recombination (HR)‐dependent allelic exchange, which requires both exogenous DNA repair proteins (e.g. λ‐Red–like systems) and endogenous functions (e.g. RecA) for HR and/or providing donor DNA templates. In general, these procedures are time‐consuming, laborious and inefficient. Here, we established a CRISPR‐assisted base‐editing (CBE) system based on the fusion of a rat cytidine deaminase (rAPOBEC1), enhanced‐specificity Cas9 nickase (eSpCas9ppD10A) and uracil DNA glycosylase inhibitor (UGI). This CBE system converts C:G into T:A without DNA strands breaks or any donor DNA template. By engineering a premature STOP codon in target spacers, the hmgA and phzO genes of P. chlororaphis were successfully interrupted at high efficiency. The phzO‐inactivated strain obtained by base editing exhibited identical phenotypic features as compared with a mutant obtained by HR‐based allelic exchange. The use of this CBE system was extended to other P. chlororaphis strains (subspecies LX24 and HT66) and also to P. fluorescens 10586, with an equally high editing efficiency. The wide applicability of this CBE method will accelerate bacterial physiology research and metabolic engineering of non‐traditional bacterial hosts.
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Affiliation(s)
- Sheng-Jie Yue
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Peng Huang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Song Li
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yu-Yuan Cai
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Wei Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xue-Hong Zhang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Pablo I Nikel
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, 2800, Denmark
| | - Hong-Bo Hu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.,National Experimental Teaching Center for Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
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38
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Persistence of plasmids targeted by CRISPR interference in bacterial populations. Proc Natl Acad Sci U S A 2022; 119:e2114905119. [PMID: 35394860 PMCID: PMC9169639 DOI: 10.1073/pnas.2114905119] [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: 12/03/2022] Open
Abstract
RNA-guided CRISPR-Cas nucleases efficiently protect bacterial cells from phage infection and plasmid transformation. Yet, the efficiency of CRISPR-Cas defense is not absolute. Mutations in either CRISPR-Cas components of the host or mobile genetic elements regions targeted by CRISPR-Cas inactivate the defensive action. Here, we show that even at conditions of active CRISPR-Cas and unaltered targeted plasmids, a kinetic equilibrium between CRISPR-Cas nucleases action and plasmid replication processes allows for existence of a small subpopulation of plasmid-bearing cells on the background of cells that have been cured from the plasmid. In nature, the observed diversification of phenotypes may allow rapid changes in the population structure to meet the demands of the environment. CRISPR-Cas systems provide prokaryotes with an RNA-guided defense against foreign mobile genetic elements (MGEs) such as plasmids and viruses. A common mechanism by which MGEs avoid interference by CRISPR consists of acquisition of escape mutations in regions targeted by CRISPR. Here, using microbiological, live microscopy and microfluidics analyses we demonstrate that plasmids can persist for multiple generations in some Escherichia coli cell lineages at conditions of continuous targeting by the type I-E CRISPR-Cas system. We used mathematical modeling to show how plasmid persistence in a subpopulation of cells mounting CRISPR interference is achieved due to the stochastic nature of CRISPR interference and plasmid replication events. We hypothesize that the observed complex dynamics provides bacterial populations with long-term benefits due to continuous maintenance of mobile genetic elements in some cells, which leads to diversification of phenotypes in the entire community and allows rapid changes in the population structure to meet the demands of a changing environment.
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Tan JY, Saleski TE, Lin XN. The effect of droplet size on syntrophic dynamics in droplet-enabled microbial co-cultivation. PLoS One 2022; 17:e0266282. [PMID: 35358282 PMCID: PMC8970485 DOI: 10.1371/journal.pone.0266282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 03/17/2022] [Indexed: 11/19/2022] Open
Abstract
Co-cultivation in microfluidic droplets has emerged as a versatile tool for the study of natural and synthetic microbial communities. In particular, the identification and characterization of syntrophic interactions in these communities is attracting increasing interest due to their critical importance for the functioning of environmental and host-associated communities as well as new biotechnological applications. However, one critical parameter in droplet-enabled co-cultivation that has evaded appropriate evaluation is the droplet size. Given the same number of initial cells, a larger droplet size can increase the length scale secreted metabolites must diffuse as well as dilute the initial concentration of cells and exchanged metabolites, impacting the community dynamics. To evaluate the effect of droplet size on a spectrum of syntrophic interactions, we cultivated a synthetic model system consisting of two E. coli auxotrophs, whose interactions could be modulated through supplementation of related amino acids in the medium. Our results demonstrate that the droplet size impacts substantially numerous aspects of the growth of a cross-feeding bi-culture, particularly the growth capacity, maximum specific growth rate, and lag time, depending on the degree of the interaction. This work heavily suggests that one droplet size does not fit all types of interactions; this parameter should be carefully evaluated and chosen in experimental studies that aim to utilize droplet-enabled co-cultivation to characterize or elucidate microbial interactions.
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Affiliation(s)
- James Y. Tan
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Tatyana E. Saleski
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Xiaoxia Nina Lin
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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40
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Immethun CM, Kathol M, Changa T, Saha R. Synthetic Biology Tool Development Advances Predictable Gene Expression in the Metabolically Versatile Soil Bacterium Rhodopseudomonas palustris. Front Bioeng Biotechnol 2022; 10:800734. [PMID: 35372317 PMCID: PMC8966681 DOI: 10.3389/fbioe.2022.800734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 02/16/2022] [Indexed: 11/13/2022] Open
Abstract
Harnessing the unique biochemical capabilities of non-model microorganisms would expand the array of biomanufacturing substrates, process conditions, and products. There are non-model microorganisms that fix nitrogen and carbon dioxide, derive energy from light, catabolize methane and lignin-derived aromatics, are tolerant to physiochemical stresses and harsh environmental conditions, store lipids in large quantities, and produce hydrogen. Model microorganisms often only break down simple sugars and require low stress conditions, but they have been engineered for the sustainable manufacture of numerous products, such as fragrances, pharmaceuticals, cosmetics, surfactants, and specialty chemicals, often by using tools from synthetic biology. Transferring complex pathways has proven to be exceedingly difficult, as the cofactors, cellular conditions, and energy sources necessary for this pathway to function may not be present in the host organism. Utilization of unique biochemical capabilities could also be achieved by engineering the host; although, synthetic biology tools developed for model microbes often do not perform as designed in other microorganisms. The metabolically versatile Rhodopseudomonas palustris CGA009, a purple non-sulfur bacterium, catabolizes aromatic compounds derived from lignin in both aerobic and anaerobic conditions and can use light, inorganic, and organic compounds for its source of energy. R. palustris utilizes three nitrogenase isozymes to fulfill its nitrogen requirements while also generating hydrogen. Furthermore, the bacterium produces two forms of RuBisCo in response to carbon dioxide/bicarbonate availability. While this potential chassis harbors many beneficial traits, stable heterologous gene expression has been problematic due to its intrinsic resistance to many antibiotics and the lack of synthetic biology parts investigated in this microbe. To address these problems, we have characterized gene expression and plasmid maintenance for different selection markers, started a synthetic biology toolbox specifically for the photosynthetic R. palustris, including origins of replication, fluorescent reporters, terminators, and 5′ untranslated regions, and employed the microbe’s endogenous plasmid for exogenous protein production. This work provides essential synthetic biology tools for engineering R. palustris’ many unique biochemical processes and has helped define the principles for expressing heterologous genes in this promising microbe through a methodology that could be applied to other non-model microorganisms.
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Dwijayanti A, Storch M, Stan GB, Baldwin GS. A modular RNA interference system for multiplexed gene regulation. Nucleic Acids Res 2022; 50:1783-1793. [PMID: 35061908 PMCID: PMC8860615 DOI: 10.1093/nar/gkab1301] [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: 08/07/2020] [Revised: 12/20/2021] [Accepted: 12/22/2021] [Indexed: 11/13/2022] Open
Abstract
The rational design and realisation of simple-to-use genetic control elements that are modular, orthogonal and robust is essential to the construction of predictable and reliable biological systems of increasing complexity. To this effect, we introduce modular Artificial RNA interference (mARi), a rational, modular and extensible design framework that enables robust, portable and multiplexed post-transcriptional regulation of gene expression in Escherichia coli. The regulatory function of mARi was characterised in a range of relevant genetic contexts, demonstrating its independence from other genetic control elements and the gene of interest, and providing new insight into the design rules of RNA based regulation in E. coli, while a range of cellular contexts also demonstrated it to be independent of growth-phase and strain type. Importantly, the extensibility and orthogonality of mARi enables the simultaneous post-transcriptional regulation of multi-gene systems as both single-gene cassettes and poly-cistronic operons. To facilitate adoption, mARi was designed to be directly integrated into the modular BASIC DNA assembly framework. We anticipate that mARi-based genetic control within an extensible DNA assembly framework will facilitate metabolic engineering, layered genetic control, and advanced genetic circuit applications.
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Affiliation(s)
| | - Marko Storch
- Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK
| | - Guy-Bart Stan
- Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK.,Department of Bioengineering, Bessemer Building, South Kensington Campus, Imperial College London, London SW7 2AZ, UK
| | - Geoff S Baldwin
- Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK.,Department of Life Sciences, Sir Alexander Fleming Building, South Kensington Campus, Imperial College London, London SW7 2AZ, UK
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Menestreau M, Rachedi R, Risoul V, Foglino M, Latifi A. The CcdB toxin is an efficient selective marker for CRISPR-plasmids developed for genome editing in cyanobacteria. MICROPUBLICATION BIOLOGY 2022; 2022:10.17912/micropub.biology.000512. [PMID: 35622522 PMCID: PMC9015812 DOI: 10.17912/micropub.biology.000512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/01/1970] [Accepted: 01/10/2022] [Indexed: 11/19/2022]
Abstract
Cyanobacteria, the only prokaryotes able of oxygenic photosynthesis are important primary producers that play a key role in the fields of agriculture, aquatic ecology and environmental protection. Their versatile metabolism makes them interesting candidates for various biotechnological applications. Recently, a great progress has been made in the field of their genetic manipulations by the development of CRISPR-based approaches. However, most of the available plasmids are rather difficult to manipulate, which renders their use challenging. In this study, we used the CcdB toxin as a selection marker to improve Cpf1-based plasmids designed for genome-editing in cyanobacteria. Our results demonstrate that this selection increased the rate of success of plasmid construction, and thus of genome editing.
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Affiliation(s)
- Martin Menestreau
- Aix Marseille Univ, CNRS, IMM, LCB, Laboratoire de Chimie Bactérienne, Marseille, France
| | - Raphaël Rachedi
- Aix Marseille Univ, CNRS, IMM, LCB, Laboratoire de Chimie Bactérienne, Marseille, France
| | - Véronique Risoul
- Aix Marseille Univ, CNRS, IMM, LCB, Laboratoire de Chimie Bactérienne, Marseille, France
| | - Maryline Foglino
- Aix Marseille Univ, CNRS, IMM, LCB, Laboratoire de Chimie Bactérienne, Marseille, France
| | - Amel Latifi
- Aix Marseille Univ, CNRS, IMM, LCB, Laboratoire de Chimie Bactérienne, Marseille, France
,
Correspondence to: Amel Latifi (
)
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Exploiting Aerobic Carboxydotrophic Bacteria for Industrial Biotechnology. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2021; 180:1-32. [PMID: 34894287 DOI: 10.1007/10_2021_178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Aerobic carboxydotrophic bacteria are a group of microorganisms which possess the unique trait to oxidize carbon monoxide (CO) as sole energy source with molecular oxygen (O2) to produce carbon dioxide (CO2) which subsequently is used for biomass formation via the Calvin-Benson-Bassham cycle. Moreover, most carboxydotrophs are also able to oxidize hydrogen (H2) with hydrogenases to drive the reduction of carbon dioxide in the absence of CO. As several abundant industrial off-gases contain significant amounts of CO, CO2, H2 as well as O2, these bacteria come into focus for industrial application to produce chemicals and fuels from such gases in gas fermentation approaches. Since the group of carboxydotrophic bacteria is rather unknown and not very well investigated, we will provide an overview about their lifestyle and the underlying metabolic characteristics, introduce promising members for industrial application, and give an overview of available genetic engineering tools. We will point to limitations and discuss challenges, which have to be overcome to apply metabolic engineering approaches and to utilize aerobic carboxydotrophs in the industrial environment.
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Mehta D, Chirmade T, Tungekar AA, Gani K, Bhambure R. Cloning and expression of antibody fragment (Fab) I: Effect of expression construct and induction strategies on light and heavy chain gene expression. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2021.108189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Rapid and Efficient BAC Recombineering: Gain & Loss Screening System. BIOTECHNOL BIOPROC E 2021. [DOI: 10.1007/s12257-020-0382-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Juteršek M, Dolinar M. A chimeric vector for dual use in cyanobacteria and Escherichia coli, tested with cystatin, a nonfluorescent reporter protein. PeerJ 2021; 9:e12199. [PMID: 34760347 PMCID: PMC8571960 DOI: 10.7717/peerj.12199] [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: 07/02/2021] [Accepted: 09/01/2021] [Indexed: 11/23/2022] Open
Abstract
Background Developing sustainable autotrophic cell factories depends heavily on the availability of robust and well-characterized biological parts. For cyanobacteria, these still lag behind the more advanced E. coli toolkit. In the course of previous protein expression experiments with cyanobacteria, we encountered inconveniences in working with currently available RSF1010-based shuttle plasmids, particularly due to their low biosafety and low yields of recombinant proteins. We also recognized some drawbacks of the commonly used fluorescent reporters, as quantification can be affected by the intrinsic fluorescence of cyanobacteria. To overcome these drawbacks, we envisioned a new chimeric vector and an alternative reporter that could be used in cyanobacterial synthetic biology and tested them in the model cyanobacterium Synechocystis sp. PCC 6803. Methods We designed the pMJc01 shuttle plasmid based on the broad host range RSFmob-I replicon. Standard cloning techniques were used for vector construction following the RFC10 synthetic biology standard. The behavior of pMJC01 was tested with selected regulatory elements in E. coli and Synechocystis sp. PCC 6803 for the biosynthesis of the established GFP reporter and of a new reporter protein, cystatin. Cystatin activity was assayed using papain as a cognate target. Results With the new vector we observed a significantly higher GFP expression in E. coli and Synechocystis sp. PCC 6803 compared to the commonly used RSF1010-based pPMQAK1. Cystatin, a cysteine protease inhibitor, was successfully expressed with the new vector in both E. coli and Synechocystis sp. PCC 6803. Its expression levels allowed quantification comparable to the standardly used fluorescent reporter GFPmut3b. An important advantage of the new vector is its improved biosafety due to the absence of plasmid regions encoding conjugative transfer components. The broadhost range vector pMJc01 could find application in synthetic biology and biotechnology of cyanobacteria due to its relatively small size, stability and ease of use. In addition, cystatin could be a useful reporter in all cell systems that do not contain papain-type proteases and inhibitors, such as cyanobacteria, and provides an alternative to fluorescent reporters or complements them.
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Affiliation(s)
- Mojca Juteršek
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia.,Current Affiliation: National Institute of Biology, Ljubljana, Slovenia
| | - Marko Dolinar
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
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Velázquez E, Al-Ramahi Y, Tellechea-Luzardo J, Krasnogor N, de Lorenzo V. Targetron-Assisted Delivery of Exogenous DNA Sequences into Pseudomonas putida through CRISPR-Aided Counterselection. ACS Synth Biol 2021; 10:2552-2565. [PMID: 34601868 PMCID: PMC8524655 DOI: 10.1021/acssynbio.1c00199] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Indexed: 11/30/2022]
Abstract
Genome editing methods based on group II introns (known as targetron technology) have long been used as a gene knockout strategy in a wide range of organisms, in a fashion independent of homologous recombination. Yet, their utility as delivery systems has typically been suboptimal due to the reduced efficiency of insertion when carrying exogenous sequences. We show that this limitation can be tackled and targetrons can be adapted as a general tool in Gram-negative bacteria. To this end, a set of broad-host-range standardized vectors were designed for the conditional expression of the Ll.LtrB intron. After establishing the correct functionality of these plasmids in Escherichia coli and Pseudomonas putida, we created a library of Ll.LtrB variants carrying cargo DNA sequences of different lengths, to benchmark the capacity of intron-mediated delivery in these bacteria. Next, we combined CRISPR/Cas9-facilitated counterselection to increase the chances of finding genomic sites inserted with the thereby engineered introns. With these novel tools, we were able to insert exogenous sequences of up to 600 bp at specific genomic locations in wild-type P. putida KT2440 and its ΔrecA derivative. Finally, we applied this technology to successfully tag P. putida with an orthogonal short sequence barcode that acts as a unique identifier for tracking this microorganism in biotechnological settings. These results show the value of the targetron approach for the unrestricted delivery of small DNA fragments to precise locations in the genomes of Gram-negative bacteria, which will be useful for a suite of genome editing endeavors.
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Affiliation(s)
- Elena Velázquez
- Systems
and Synthetic Biology Department, Centro
Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid 28049, Spain
| | - Yamal Al-Ramahi
- Systems
and Synthetic Biology Department, Centro
Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid 28049, Spain
| | - Jonathan Tellechea-Luzardo
- Interdisciplinary
Computing and Complex Biosystems (ICOS) Research Group, Newcastle University, Newcastle Upon Tyne NE4 5TG, U.K.
| | - Natalio Krasnogor
- Interdisciplinary
Computing and Complex Biosystems (ICOS) Research Group, Newcastle University, Newcastle Upon Tyne NE4 5TG, U.K.
| | - Víctor de Lorenzo
- Systems
and Synthetic Biology Department, Centro
Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid 28049, Spain
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Improved Dynamic Range of a Rhamnose-Inducible Promoter for Gene Expression in Burkholderia spp. Appl Environ Microbiol 2021; 87:e0064721. [PMID: 34190606 DOI: 10.1128/aem.00647-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
A diverse genetic toolkit is critical for understanding bacterial physiology and genotype-phenotype relationships. Inducible promoter systems are an integral part of this toolkit. In Burkholderia and related species, the l-rhamnose-inducible promoter is among the first choices due to its tight control and the lack of viable alternatives. To improve upon its maximum activity and dynamic range, we explored the effect of promoter system modifications in Burkholderia cenocepacia with a LacZ-based reporter. By combining the bacteriophage T7 gene 10 stem-loop and engineered rhaI transcription factor-binding sites, we obtained a rhamnose-inducible system with a 6.5-fold and 3.0-fold increases in maximum activity and dynamic range, respectively, compared to the native promoter. We then added the modified promoter system to pSCrhaB2 and pSC201, common genetic tools used for plasmid-based and chromosome-based gene expression, respectively, in Burkholderia, creating pSCrhaB2plus and pSC201plus. We demonstrated the utility of pSCrhaB2plus for gene expression in B. thailandensis, B. multivorans, and B. vietnamiensis and used pSC201plus to control highly expressed essential genes from the chromosome of B. cenocepacia. The utility of the modified system was demonstrated as we recovered viable mutants to control ftsZ, rpoBC, and rpsF, whereas the unmodified promoter was unable to control rpsF. The modified expression system allowed control of an essential gene depletion phenotype at lower levels of l-rhamnose, the inducer. pSCRhaB2plus and pSC201plus are expected to be valuable additions to the genetic toolkit for Burkholderia and related species. IMPORTANCE Species of Burkholderia are dually recognized as being of attractive biotechnological potential but also opportunistic pathogens for immunocompromised individuals. Understanding the genotype-phenotype relationship is critical for synthetic biology approaches in Burkholderia to disentangle pathogenic from beneficial traits. A diverse genetic toolkit, including inducible promoters, is the foundation for these investigations. Thus, we sought to improve on the commonly used rhamnose-inducible promoter system. Our modifications resulted in both higher levels of heterologous protein expression and broader control over highly expressed essential genes in B. cenocepacia. The significance of our work is in expanding the genetic toolkit to enable more comprehensive studies into Burkholderia and related bacteria.
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Stukenberg D, Hensel T, Hoff J, Daniel B, Inckemann R, Tedeschi JN, Nousch F, Fritz G. The Marburg Collection: A Golden Gate DNA Assembly Framework for Synthetic Biology Applications in Vibrio natriegens. ACS Synth Biol 2021; 10:1904-1919. [PMID: 34255476 DOI: 10.1021/acssynbio.1c00126] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Vibrio natriegens is known as the world's fastest growing organism with a doubling time of less than 10 min. This incredible growth speed empowers V. natriegens as a chassis for synthetic and molecular biology, potentially replacing E. coli in many applications. While first genetic parts have been built and tested for V. natriegens, a comprehensive toolkit containing well-characterized and standardized parts did not exist. To close this gap, we created the Marburg Collection-a highly flexible Golden Gate cloning toolbox optimized for the emerging chassis organism V. natriegens, containing 191 genetic parts. The Marburg Collection overcomes the paradigm of plasmid construction-integrating inserts into a backbone-by enabling the de novo assembly of plasmids from basic genetic parts. This allows users to select the plasmid replication origin and resistance part independently, which is highly advantageous when limited knowledge about the behavior of those parts in the target organism is available. Additional design highlights of the Marburg Collection are novel connector parts, which facilitate modular circuit assembly and, optionally, the inversion of individual transcription units to reduce transcriptional crosstalk in multigene constructs. To quantitatively characterize the genetic parts contained in the Marburg Collection in V. natriegens, we developed a reliable microplate reader measurement workflow for reporter experiments and overcame organism-specific challenges. We think the Marburg Collection with its thoroughly characterized parts will provide a valuable resource for the growing V. natriegens community.
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Affiliation(s)
- Daniel Stukenberg
- Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg 35032, Germany
- Max-Planck Institute for Terrestrial Microbiology, Marburg 35043, Germany
| | - Tobias Hensel
- Faculty of Chemistry, Philipps-Universität Marburg, Marburg 35032, Germany
| | - Josef Hoff
- Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg 35032, Germany
- Max-Planck Institute for Terrestrial Microbiology, Marburg 35043, Germany
| | - Benjamin Daniel
- Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg 35032, Germany
- Institute of Microbiology, ETH Zurich, Zürich 8093, Switzerland
| | - René Inckemann
- Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg 35032, Germany
- Max-Planck Institute for Terrestrial Microbiology, Marburg 35043, Germany
| | - Jamie N. Tedeschi
- School of Molecular Sciences, The University of Western Australia, Perth 6009, Australia
| | - Franziska Nousch
- Faculty of Chemistry, Philipps-Universität Marburg, Marburg 35032, Germany
| | - Georg Fritz
- School of Molecular Sciences, The University of Western Australia, Perth 6009, Australia
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Outer membrane permeability: Antimicrobials and diverse nutrients bypass porins in Pseudomonas aeruginosa. Proc Natl Acad Sci U S A 2021; 118:2107644118. [PMID: 34326266 PMCID: PMC8346889 DOI: 10.1073/pnas.2107644118] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Novel antibiotics are urgently needed to resolve the current antimicrobial resistance crisis. For critical pathogens, drug entry through the cell envelope is one of the major challenges in the development of effective novel antibiotics. Envelope proteins forming water-filled channels, so-called porins, are commonly thought to be essential for entry of hydrophilic molecules, but we show here for the critical pathogen Pseudomonas aeruginosa that almost all antibiotics and diverse hydrophilic nutrients bypass porins and instead permeate directly through the outer membrane lipid bilayer. However, carboxylate groups hinder bilayer penetration, and Pseudomonas thus needs porins for efficient utilization of carboxylate-containing nutrients such as succinate. The major porin-independent entry route might open opportunities for facilitating drug delivery into bacteria. Gram-negative bacterial pathogens have an outer membrane that restricts entry of molecules into the cell. Water-filled protein channels in the outer membrane, so-called porins, facilitate nutrient uptake and are thought to enable antibiotic entry. Here, we determined the role of porins in a major pathogen, Pseudomonas aeruginosa, by constructing a strain lacking all 40 identifiable porins and 15 strains carrying only a single unique type of porin and characterizing these strains with NMR metabolomics and antimicrobial susceptibility assays. In contrast to common assumptions, all porins were dispensable for Pseudomonas growth in rich medium and consumption of diverse hydrophilic nutrients. However, preferred nutrients with two or more carboxylate groups such as succinate and citrate permeated poorly in the absence of porins. Porins provided efficient translocation pathways for these nutrients with broad and overlapping substrate selectivity while efficiently excluding all tested antibiotics except carbapenems, which partially entered through OprD. Porin-independent permeation of antibiotics through the outer-membrane lipid bilayer was hampered by carboxylate groups, consistent with our nutrient data. Together, these results challenge common assumptions about the role of porins by demonstrating porin-independent permeation of the outer-membrane lipid bilayer as a major pathway for nutrient and drug entry into the bacterial cell.
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