1
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Gilliot PA, Gorochowski TE. Transfer learning for cross-context prediction of protein expression from 5'UTR sequence. Nucleic Acids Res 2024:gkae491. [PMID: 38864396 DOI: 10.1093/nar/gkae491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 04/28/2024] [Accepted: 05/28/2024] [Indexed: 06/13/2024] Open
Abstract
Model-guided DNA sequence design can accelerate the reprogramming of living cells. It allows us to engineer more complex biological systems by removing the need to physically assemble and test each potential design. While mechanistic models of gene expression have seen some success in supporting this goal, data-centric, deep learning-based approaches often provide more accurate predictions. This accuracy, however, comes at a cost - a lack of generalization across genetic and experimental contexts that has limited their wider use outside the context in which they were trained. Here, we address this issue by demonstrating how a simple transfer learning procedure can effectively tune a pre-trained deep learning model to predict protein translation rate from 5' untranslated region (5'UTR) sequence for diverse contexts in Escherichia coli using a small number of new measurements. This allows for important model features learnt from expensive massively parallel reporter assays to be easily transferred to new settings. By releasing our trained deep learning model and complementary calibration procedure, this study acts as a starting point for continually refined model-based sequence design that builds on previous knowledge and future experimental efforts.
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Affiliation(s)
- Pierre-Aurélien Gilliot
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Thomas E Gorochowski
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
- BrisEngBio, School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
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2
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Zhang C, Dang W, Zhang J, Wang C, Zhong P, Wang Z, Yang Y, Wang Y, Yan X. Development of a paper-based transcription aptasensor for convenient urinary uric acid self-testing. Int J Biol Macromol 2024; 271:132241. [PMID: 38768916 DOI: 10.1016/j.ijbiomac.2024.132241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/15/2024] [Accepted: 05/07/2024] [Indexed: 05/22/2024]
Abstract
The abnormal uric acid (UA) level in urine can serve as warning signals of many diseases, such as gout and metabolic cardiovascular diseases. The current methods for detecting UA face limitations of instrument dependence and the requirement for non-invasiveness, making it challenging to fulfill the need for home-based application. In this study, we designed an aptasensor that combined UA-specific transcriptional regulation and a fluorescent RNA aptamer for convenient urinary UA testing. The concentration of UA can be translated into the intensity of fluorescent signals. The aptasensor showed higher sensitivity and more robust anti-interference performance. UA levels in the urine of different volunteers could be accurately tested using this method. In addition, a paper-based aptasensor for UA self-testing was manufactured, in which the urinary UA levels could be determined using a smartphone-based colorimetric approach. This work not only demonstrates a new approach for the design of disease-associated aptasensor, but also offers promising ideas for home-based detection of UA.
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Affiliation(s)
- Chengyu Zhang
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China
| | - Weifan Dang
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China
| | - Jingjing Zhang
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China
| | - Cong Wang
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China
| | - Peng Zhong
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China
| | - Zhaoxin Wang
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China
| | - Yufan Yang
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China
| | - Yuefei Wang
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China.
| | - Xiaohui Yan
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China.
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3
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Radde N, Mortensen GA, Bhat D, Shah S, Clements JJ, Leonard SP, McGuffie MJ, Mishler DM, Barrick JE. Measuring the burden of hundreds of BioBricks defines an evolutionary limit on constructability in synthetic biology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.08.588465. [PMID: 38645188 PMCID: PMC11030366 DOI: 10.1101/2024.04.08.588465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Engineered DNA will slow the growth of a host cell if it redirects limiting resources or otherwise interferes with homeostasis. Populations of engineered cells can rapidly become dominated by "escape mutants" that evolve to alleviate this burden by inactivating the intended function. Synthetic biologists working with bacteria rely on genetic parts and devices encoded on plasmids, but the burden of different engineered DNA sequences is rarely characterized. We measured how 301 BioBricks on high-copy plasmids affected the growth rate of Escherichia coli . Of these, 59 (19.6%) negatively impacted growth. The burden imposed by engineered DNA is commonly associated with diverting ribosomes or other gene expression factors away from producing endogenous genes that are essential for cellular replication. In line with this expectation, BioBricks exhibiting burden were more likely to contain highly active constitutive promoters and strong ribosome binding sites. By monitoring how much each BioBrick reduced expression of a chromosomal GFP reporter, we found that the burden of most, but not all, BioBricks could be wholly explained by diversion of gene expression resources. Overall, no BioBricks reduced the growth rate of E. coli by >45%, which agreed with a population genetic model that predicts such plasmids should be "unclonable" because escape mutants will take over during growth of a bacterial colony or small laboratory culture from a transformed cell. We made this model available as an interactive web tool for synthetic biology education and added our burden measurements to the iGEM Registry descriptions of each BioBrick.
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4
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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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5
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Ba F, Zhang Y, Ji X, Liu WQ, Ling S, Li J. Expanding the toolbox of probiotic Escherichia coli Nissle 1917 for synthetic biology. Biotechnol J 2024; 19:e2300327. [PMID: 37800393 DOI: 10.1002/biot.202300327] [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: 07/06/2023] [Revised: 09/11/2023] [Accepted: 09/27/2023] [Indexed: 10/07/2023]
Abstract
Escherichia coli Nissle 1917 (EcN) is a probiotic microbe that has the potential to be developed as a promising chassis for synthetic biology applications. However, the molecular tools and techniques for utilizing EcN remain to be further explored. To address this opportunity, the EcN-based toolbox was systematically expanded, enabling EcN as a powerful platform for more applications. First, two EcN cryptic plasmids and other compatible plasmids were genetically engineered to enrich the manipulable plasmid toolbox for multiple gene coexpression. Next, two EcN-based technologies were developed, including the conjugation strategy for DNA transfer, and quantification of protein expression capability. Finally, the EcN-based applications were further expanded by developing EcN native integrase-mediated genetic engineering and establishing an in vitro cell-free protein synthesis (CFPS) system. Overall, this study expanded the toolbox for manipulating and making full use of EcN as a commonly used probiotic chassis, providing several simplified, dependable, and predictable strategies for researchers working in synthetic biology fields.
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Affiliation(s)
- Fang Ba
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yufei Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Xiangyang Ji
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Wan-Qiu Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Shengjie Ling
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Jian Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
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6
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De Wannemaeker L, Mey F, Bervoets I, Ver Cruysse M, Baldwin GS, De Mey M. Standardization of Fluorescent Reporter Assays in Synthetic Biology across the Visible Light Spectrum. ACS Synth Biol 2023; 12:3591-3607. [PMID: 37981737 PMCID: PMC10729763 DOI: 10.1021/acssynbio.3c00386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 10/24/2023] [Accepted: 10/27/2023] [Indexed: 11/21/2023]
Abstract
In synthetic biology, Fluorescent reporters are frequently used to characterize the expression levels obtained from both genetic parts such as promoters and ribosome binding sites as well as from complex genetic circuits. To this end, plate readers offer an easy and high-throughput way of characterizing both the growth and fluorescence expression levels of cell cultures. However, despite the similar mode of action used in different devices, their output is not comparable due to intrinsic differences in their setup. Additionally, the generated output is expressed using arbitrary units, limiting reliable comparison of results to measurements taken within one single experiment using one specific plate reader, hampering the transferability of data across different plate readers and laboratories. This article presents an easy and accessible calibration method for transforming the device-specific output into a standardized output expressing the amount of fluorescence per well as a known equivalent fluorophore concentration per cell for fluorescent reporters spanning the visible light spectrum. This calibration method follows a 2-fold approach determining both the estimated number of cells and the equivalent chemical fluorophore concentration per well. It will contribute to the comparison of plate reader experiments between different laboratories across the world and will therefore greatly improve the reliability and exchange of both results and genetic parts between research groups.
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Affiliation(s)
- Lien De Wannemaeker
- Centre
for Synthetic Biology, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Friederike Mey
- Centre
for Synthetic Biology, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Indra Bervoets
- Vrije
Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Michiel Ver Cruysse
- Centre
for Synthetic Biology, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Geoff S. Baldwin
- Imperial
College London, Sir Alexander Fleming Building, South Kensington, London SW7 2AZ, United Kingdom
| | - Marjan De Mey
- Centre
for Synthetic Biology, Ghent University, Coupure links 653, 9000 Ghent, Belgium
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7
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Lux MW, Strychalski EA, Vora GJ. Advancing reproducibility can ease the 'hard truths' of synthetic biology. Synth Biol (Oxf) 2023; 8:ysad014. [PMID: 38022744 PMCID: PMC10640854 DOI: 10.1093/synbio/ysad014] [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: 03/07/2023] [Revised: 07/26/2023] [Accepted: 10/04/2023] [Indexed: 12/01/2023] Open
Abstract
Reproducibility has been identified as an outstanding challenge in science, and the field of synthetic biology is no exception. Meeting this challenge is critical to allow the transformative technological capabilities emerging from this field to reach their full potential to benefit the society. We discuss the current state of reproducibility in synthetic biology and how improvements can address some of the central shortcomings in the field. We argue that the successful adoption of reproducibility as a routine aspect of research and development requires commitment spanning researchers and relevant institutions via education, incentivization and investment in related infrastructure. The urgency of this topic pervades synthetic biology as it strives to advance fundamental insights and unlock new capabilities for safe, secure and scalable applications of biotechnology. Graphical Abstract.
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Affiliation(s)
- Matthew W Lux
- Research & Operations Directorate, U.S. Army Combat Capabilities Development Command Chemical Biological Center, APG, MD 21010, USA
| | - Elizabeth A Strychalski
- Cellular Engineering Group, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Gary J Vora
- Center for Bio/Molecular Science & Engineering, U.S. Naval Research Laboratory, Washington, DC 20375, USA
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8
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Herzog JM, Sick V. Quantitative Spectroscopic Characterization of Near-UV/visible E. coli (pYAC4), B. subtilis (PY79), and Green Bread Mold Fungus Fluorescence for Diagnostic Applications. J Fluoresc 2023; 33:1813-1825. [PMID: 36847932 DOI: 10.1007/s10895-023-03183-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 02/13/2023] [Indexed: 03/01/2023]
Abstract
Ultraviolet (UV)-excited visible fluorescence is an attractive option for low-cost, low-complexity, rapid imaging of bacterial and fungal samples for imaging diagnostics in the biomedical community. While several studies have shown there is potential for identification of microbial samples, very little quantitative information is available in the literature for the purposes of diagnostic design. In this work, two non-pathogenic bacteria samples (E. coli pYAC4, and B. subtilis PY79) and a wild-cultivated green bread mold fungus sample are characterized spectroscopically for the purpose of diagnostic design. For each sample, fluorescence spectra excited with low-power near-UV continuous wave (CW) sources, and extinction and elastic scattering spectra are captured and compared. Absolute fluorescence intensity per cell excited at 340 nm is estimated from imaging measurements of aqueous samples. The results are used to estimate detection limits for a prototypical imaging experiment. It was found that fluorescence imaging is feasible for as few as 35 bacteria cells (or [Formula: see text]30 µm3 of bacteria) per pixel, and that the fluorescence intensity per unit volume is similar for the three samples tested here. A discussion and model of the mechanism of bacterial fluorescence in E. coli is provided.
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Affiliation(s)
- Joshua M Herzog
- Department of Mechanical Engineering, University of Michigan, 2350 Hayward St., Ann Arbor, MI 48109, USA.
| | - Volker Sick
- Department of Mechanical Engineering, University of Michigan, 2350 Hayward St., Ann Arbor, MI 48109, USA
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9
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Mager M, Pineda Hernandez H, Brandenburg F, López-Maury L, McCormick AJ, Nürnberg DJ, Orthwein T, Russo DA, Victoria AJ, Wang X, Zedler JAZ, Branco dos Santos F, Schmelling NM. Interlaboratory Reproducibility in Growth and Reporter Expression in the Cyanobacterium Synechocystis sp. PCC 6803. ACS Synth Biol 2023; 12:1823-1835. [PMID: 37246820 PMCID: PMC10278186 DOI: 10.1021/acssynbio.3c00150] [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: 03/11/2023] [Indexed: 05/30/2023]
Abstract
In recent years, a plethora of new synthetic biology tools for use in cyanobacteria have been published; however, their reported characterizations often cannot be reproduced, greatly limiting the comparability of results and hindering their applicability. In this interlaboratory study, the reproducibility of a standard microbiological experiment for the cyanobacterial model organism Synechocystis sp. PCC 6803 was assessed. Participants from eight different laboratories quantified the fluorescence intensity of mVENUS as a proxy for the transcription activity of the three promoters PJ23100, PrhaBAD, and PpetE over time. In addition, growth rates were measured to compare growth conditions between laboratories. By establishing strict and standardized laboratory protocols, reflecting frequently reported methods, we aimed to identify issues with state-of-the-art procedures and assess their effect on reproducibility. Significant differences in spectrophotometer measurements across laboratories from identical samples were found, suggesting that commonly used reporting practices of optical density values need to be supplemented by cell count or biomass measurements. Further, despite standardized light intensity in the incubators, significantly different growth rates between incubators used in this study were observed, highlighting the need for additional reporting requirements of growth conditions for phototrophic organisms beyond the light intensity and CO2 supply. Despite the use of a regulatory system orthogonal to Synechocystis sp. PCC 6803, PrhaBAD, and a high level of protocol standardization, ∼32% variation in promoter activity under induced conditions was found across laboratories, suggesting that the reproducibility of other data in the field of cyanobacteria might be affected similarly.
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Affiliation(s)
- Maurice Mager
- Institute
for Synthetic Microbiology, Heinrich Heine
University Duesseldorf, Universitaetsstrasse 1, 40225 Duesseldorf, Germany
| | - Hugo Pineda Hernandez
- Molecular
Microbial Physiology Group, Swammerdam Institute for Life Sciences,
Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - Fabian Brandenburg
- Helmholtz
Centre for Environmental Research (UFZ), Permoserstrasse 15, 04318 Leipzig, Germany
| | - Luis López-Maury
- Instituto
de Bioquímica Vegetal y Fotosíntesis, University of Seville − CSIC, Américo Vespucio 49, 41092 Sevilla, Spain
- Departamento
de Bioquímica Vegetal y Biología Molecular, Facultad
de Biología, University of Seville, Avenida Reina Mercedes, 41012 Sevilla, Spain
| | - Alistair J. McCormick
- Institute
of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, 1.04 Daniel Rutherford Building, King’s
Buildings, EH9 3BF Edinburgh, U.K.
| | - Dennis J. Nürnberg
- Department
of Physics, Experimental Biophysics, Freie
University Berlin, Arnimallee
14, 14195 Berlin, Germany
- Dahlem
Centre of Plant Sciences, Freie Universität
Berlin, Albrecht-Thaer-Weg 6, 14195 Berlin, Germany
| | - Tim Orthwein
- Interfaculty
Institute of Microbiology and Infection Medicine, University of Tuebingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - David A. Russo
- Institute
for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich Schiller University Jena, Lessingstrasse 8, 07743 Jena, Germany
| | - Angelo Joshua Victoria
- Institute
of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, 1.04 Daniel Rutherford Building, King’s
Buildings, EH9 3BF Edinburgh, U.K.
| | - Xiaoran Wang
- Department
of Physics, Experimental Biophysics, Freie
University Berlin, Arnimallee
14, 14195 Berlin, Germany
| | - Julie A. Z. Zedler
- Matthias
Schleiden Institute for Genetics, Bioinformatics and Molecular Botany,
Synthetic Biology of Photosynthetic Organisms, Friedrich Schiller University Jena, Dornburgerstrasse 159, 07743 Jena, Germany
| | - Filipe Branco dos Santos
- Molecular
Microbial Physiology Group, Swammerdam Institute for Life Sciences,
Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - Nicolas M. Schmelling
- Institute
for Synthetic Microbiology, Heinrich Heine
University Duesseldorf, Universitaetsstrasse 1, 40225 Duesseldorf, Germany
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10
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Ba F, Ji X, Huang S, Zhang Y, Liu WQ, Liu Y, Ling S, Li J. Engineering Escherichia coli to Utilize Erythritol as Sole Carbon Source. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2207008. [PMID: 36938858 DOI: 10.1002/advs.202207008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 02/16/2023] [Indexed: 05/18/2023]
Abstract
Erythritol, one of the natural sugar alcohols, is widely used as a sugar substitute sweetener in food industries. Humans themselves are not able to catabolize erythritol and their gut microbes lack related catabolic pathways either to metabolize erythritol. Here, Escherichia coli (E. coli) is engineered to utilize erythritol as sole carbon source aiming for defined applications. First, the erythritol metabolic gene cluster is isolated and the erythritol-binding transcriptional repressor and its DNA-binding site are experimentally characterized. Transcriptome analysis suggests that carbohydrate metabolism-related genes in the engineered E. coli are overall upregulated. In particular, the enzymes of transaldolase (talA and talB) and transketolase (tktA and tktB) are notably overexpressed (e.g., the expression of tktB is improved by nearly sixfold). By overexpression of the four genes, cell growth can be increased as high as three times compared to the cell cultivation without overexpression. Finally, engineered E. coli strains can be used as a living detector to distinguish erythritol-containing soda soft drinks and can grow in the simulated intestinal fluid supplemented with erythritol. This work is expected to inspire the engineering of more hosts to respond and utilize erythritol for broad applications in metabolic engineering, synthetic biology, and biomedical engineering.
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Affiliation(s)
- Fang Ba
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China
| | - Xiangyang Ji
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China
| | - Shuhui Huang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China
| | - Yufei Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China
| | - Wan-Qiu Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China
| | - Yifan Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China
| | - Shengjie Ling
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China
| | - Jian Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China
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11
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Lammens EM, Feyaerts N, Kerremans A, Boon M, Lavigne R. Assessing the Orthogonality of Phage-Encoded RNA Polymerases for Tailored Synthetic Biology Applications in Pseudomonas Species. Int J Mol Sci 2023; 24:ijms24087175. [PMID: 37108338 PMCID: PMC10138996 DOI: 10.3390/ijms24087175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/27/2023] [Accepted: 03/27/2023] [Indexed: 04/29/2023] Open
Abstract
The phage T7 RNA polymerase (RNAP) and lysozyme form the basis of the widely used pET expression system for recombinant expression in the biotechnology field and as a tool in microbial synthetic biology. Attempts to transfer this genetic circuitry from Escherichia coli to non-model bacterial organisms with high potential have been restricted by the cytotoxicity of the T7 RNAP in the receiving hosts. We here explore the diversity of T7-like RNAPs mined directly from Pseudomonas phages for implementation in Pseudomonas species, thus relying on the co-evolution and natural adaptation of the system towards its host. By screening and characterizing different viral transcription machinery using a vector-based system in P. putida., we identified a set of four non-toxic phage RNAPs from phages phi15, PPPL-1, Pf-10, and 67PfluR64PP, showing a broad activity range and orthogonality to each other and the T7 RNAP. In addition, we confirmed the transcription start sites of their predicted promoters and improved the stringency of the phage RNAP expression systems by introducing and optimizing phage lysozymes for RNAP inhibition. This set of viral RNAPs expands the adaption of T7-inspired circuitry towards Pseudomonas species and highlights the potential of mining tailored genetic parts and tools from phages for their non-model host.
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Affiliation(s)
- Eveline-Marie Lammens
- Laboratory of Gene Technology, Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21 Box 2462, 3001 Leuven, Belgium
| | - Nathalie Feyaerts
- Laboratory of Gene Technology, Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21 Box 2462, 3001 Leuven, Belgium
| | - Alison Kerremans
- Laboratory of Gene Technology, Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21 Box 2462, 3001 Leuven, Belgium
| | - Maarten Boon
- Laboratory of Gene Technology, Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21 Box 2462, 3001 Leuven, Belgium
| | - Rob Lavigne
- Laboratory of Gene Technology, Department of Biosystems, KU Leuven, Kasteelpark Arenberg 21 Box 2462, 3001 Leuven, Belgium
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12
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Transcriptomics-Driven Characterization of LUZ100, a T7-like Pseudomonas Phage with Temperate Features. mSystems 2023; 8:e0118922. [PMID: 36794936 PMCID: PMC10134795 DOI: 10.1128/msystems.01189-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Autographiviridae is a diverse yet distinct family of bacterial viruses marked by a strictly lytic lifestyle and a generally conserved genome organization. Here, we characterized Pseudomonas aeruginosa phage LUZ100, a distant relative of type phage T7. LUZ100 is a podovirus with a limited host range which likely uses lipopolysaccharide (LPS) as a phage receptor. Interestingly, infection dynamics of LUZ100 indicated moderate adsorption rates and low virulence, hinting at temperate characteristics. This hypothesis was supported by genomic analysis, which showed that LUZ100 shares the conventional T7-like genome organization yet carries key genes associated with a temperate lifestyle. To unravel the peculiar characteristics of LUZ100, ONT-cappable-seq transcriptomics analysis was performed. These data provided a bird's-eye view of the LUZ100 transcriptome and enabled the discovery of key regulatory elements, antisense RNA, and transcriptional unit structures. The transcriptional map of LUZ100 also allowed us to identify new RNA polymerase (RNAP)-promoter pairs that can form the basis for biotechnological parts and tools for new synthetic transcription regulation circuitry. The ONT-cappable-seq data revealed that the LUZ100 integrase and a MarR-like regulator (proposed to be involved in the lytic/lysogeny decision) are actively cotranscribed in an operon. In addition, the presence of a phage-specific promoter transcribing the phage-encoded RNA polymerase raises questions on the regulation of this polymerase and suggests that it is interwoven with the MarR-based regulation. This transcriptomics-driven characterization of LUZ100 supports recent evidence that T7-like phages should not automatically be assumed to have a strictly lytic life cycle. IMPORTANCE Bacteriophage T7, considered the "model phage" of the Autographiviridae family, is marked by a strictly lytic life cycle and conserved genome organization. Recently, novel phages within this clade have emerged which display characteristics associated with a temperate life cycle. Screening for temperate behavior is of utmost importance in fields like phage therapy, where strictly lytic phages are generally required for therapeutic applications. In this study, we applied an omics-driven approach to characterize the T7-like Pseudomonas aeruginosa phage LUZ100. These results led to the identification of actively transcribed lysogeny-associated genes in the phage genome, pointing out that temperate T7-like phages are emerging more frequent than initially thought. In short, the combination of genomics and transcriptomics allowed us to obtain a better understanding of the biology of nonmodel Autographiviridae phages, which can be used to optimize the implementation of phages and their regulatory elements in phage therapy and biotechnological applications, respectively.
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13
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González-Cebrián A, Borràs-Ferrís J, Boada Y, Vignoni A, Ferrer A, Picó J. PLATERO: A calibration protocol for plate reader green fluorescence measurements. Front Bioeng Biotechnol 2023; 11:1104445. [PMID: 36741754 PMCID: PMC9895789 DOI: 10.3389/fbioe.2023.1104445] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 01/09/2023] [Indexed: 01/22/2023] Open
Abstract
One of the most common sources of information in Synthetic Biology is the data coming from plate reader fluorescence measurements. These experiments provide a measure of the light emitted by a certain fluorescent molecule, such as the Green Fluorescent Protein (GFP). However, these measurements are generally expressed in arbitrary units and are affected by the measurement device gain. This limits the range of measurements in a single experiment and hampers the comparison of results among experiments. In this work, we describe PLATERO, a calibration protocol to express fluorescence measures in concentration units of a reference fluorophore. The protocol removes the gain effect of the measurement device on the acquired data. In addition, the fluorescence intensity values are transformed into units of concentration using a Fluorescein calibration model. Both steps are expressed in a single mathematical expression that returns normalized, gain-independent, and comparable data, even if the acquisition was done at different device gain levels. Most important, the PLATERO embeds a Linearity and Bias Analysis that provides an assessment of the uncertainty of the model estimations, and a Reproducibility and Repeatability analysis that evaluates the sources of variability originating from the measurements and the equipment. All the functions used to build the model, exploit it with new data, and perform the uncertainty and variability assessment are available in an open access repository.
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Affiliation(s)
- Alba González-Cebrián
- Multivariate Statistical Engineering Group, Department of Applied Statistics and O.R. and Quality, Universitat Politècnica de València, València, Spain
| | - Joan Borràs-Ferrís
- Multivariate Statistical Engineering Group, Department of Applied Statistics and O.R. and Quality, Universitat Politècnica de València, València, Spain
| | - Yadira Boada
- Synthetic Biology and Biosystems Control Lab, Instituto de Automática e Informática Industrial, Universitat Politècnica de València, València, Spain
| | - Alejandro Vignoni
- Synthetic Biology and Biosystems Control Lab, Instituto de Automática e Informática Industrial, Universitat Politècnica de València, València, Spain,*Correspondence: Alejandro Vignoni,
| | - Alberto Ferrer
- Multivariate Statistical Engineering Group, Department of Applied Statistics and O.R. and Quality, Universitat Politècnica de València, València, Spain
| | - Jesús Picó
- Synthetic Biology and Biosystems Control Lab, Instituto de Automática e Informática Industrial, Universitat Politècnica de València, València, Spain
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14
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Aldulijan I, Beal J, Billerbeck S, Bouffard J, Chambonnier G, Ntelkis N, Guerreiro I, Holub M, Ross P, Selvarajah V, Sprent N, Vidal G, Vignoni A. Functional Synthetic Biology. Synth Biol (Oxf) 2023; 8:ysad006. [PMID: 37073284 PMCID: PMC10105873 DOI: 10.1093/synbio/ysad006] [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: 06/30/2022] [Revised: 02/17/2023] [Accepted: 04/04/2023] [Indexed: 04/20/2023] Open
Abstract
Synthetic biologists have made great progress over the past decade in developing methods for modular assembly of genetic sequences and in engineering biological systems with a wide variety of functions in various contexts and organisms. However, current paradigms in the field entangle sequence and functionality in a manner that makes abstraction difficult, reduces engineering flexibility and impairs predictability and design reuse. Functional Synthetic Biology aims to overcome these impediments by focusing the design of biological systems on function, rather than on sequence. This reorientation will decouple the engineering of biological devices from the specifics of how those devices are put to use, requiring both conceptual and organizational change, as well as supporting software tooling. Realizing this vision of Functional Synthetic Biology will allow more flexibility in how devices are used, more opportunity for reuse of devices and data, improvements in predictability and reductions in technical risk and cost.
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Affiliation(s)
- Ibrahim Aldulijan
- Systems Engineering, Stevens Institute of Technology, 1 Castle Point Terrace, Hoboken, 07030, NJ, USA
| | | | - Sonja Billerbeck
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Jeff Bouffard
- Centre for Applied Synthetic Biology, and Department of Biology, Concordia University, 7141 Sherbrooke Street West, Montréal, H4B 1R6, Québec, Canada
| | - Gaël Chambonnier
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, 02139, MA, USA
| | - Nikolaos Ntelkis
- Specialized Metabolism research group, Center for Plant Systems Biology, VIB-Ghent University, Technologiepark 71, Zwijnaarde, 9052, Belgium
| | - Isaac Guerreiro
- iGEM Foundation, 45 Prospect Street, Cambridge, 02139, MA, USA
| | - Martin Holub
- Delft University of Technology, Van der Maasweg 9, 2629 HZ, The Netherlands
| | - Paul Ross
- BioStrat Marketing, 9965 Harbour Lake Circle, Boynton Beach, FL, 33437, USA
| | | | - Noah Sprent
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, Exhibition Road, SW7 2AZ, UK
| | - Gonzalo Vidal
- Interdisciplinary Computing and Complex BioSystems (ICOS) research group, School of Computing, Newcastle University, Devonshire Building, Devonshire Terrace, NE1 7RU, Newcastle Upon Tyne, UK
| | - Alejandro Vignoni
- Synthetic Biology and Biosystems Control Lab, Instituto de Automatica e Informatica Industrial, Universitat Politecnica de Valencia, Camino de Vera s/n, 46022, Valencia, Spain
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15
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Csibra E, Stan GB. Absolute protein quantification using fluorescence measurements with FPCountR. Nat Commun 2022; 13:6600. [PMID: 36329019 PMCID: PMC9633595 DOI: 10.1038/s41467-022-34232-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 10/19/2022] [Indexed: 11/06/2022] Open
Abstract
This paper presents a generalisable method for the calibration of fluorescence readings on microplate readers, in order to convert arbitrary fluorescence units into absolute units. FPCountR relies on the generation of bespoke fluorescent protein (FP) calibrants, assays to determine protein concentration and activity, and a corresponding analytical workflow. We systematically characterise the assay protocols for accuracy, sensitivity and simplicity, and describe an 'ECmax' assay that outperforms the others and even enables accurate calibration without requiring the purification of FPs. To obtain cellular protein concentrations, we consider methods for the conversion of optical density to either cell counts or alternatively to cell volumes, as well as examining how cells can interfere with protein counting via fluorescence quenching, which we quantify and correct for the first time. Calibration across different instruments, disparate filter sets and mismatched gains is demonstrated to yield equivalent results. It also reveals that mCherry absorption at 600 nm does not confound cell density measurements unless expressed to over 100,000 proteins per cell. FPCountR is presented as pair of open access tools (protocol and R package) to enable the community to use this method, and ultimately to facilitate the quantitative characterisation of synthetic microbial circuits.
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Affiliation(s)
- Eszter Csibra
- grid.7445.20000 0001 2113 8111Department of Bioengineering, Imperial College Centre for Synthetic Biology (IC-CSynB), Imperial College London, London, SW7 2AY UK
| | - Guy-Bart Stan
- grid.7445.20000 0001 2113 8111Department of Bioengineering, Imperial College Centre for Synthetic Biology (IC-CSynB), Imperial College London, London, SW7 2AY UK
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16
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Vidal G, Vitalis C, Muñoz Silva M, Castillo-Passi C, Yáñez Feliú G, Federici F, Rudge TJ. Accurate characterization of dynamic microbial gene expression and growth rate profiles. Synth Biol (Oxf) 2022; 7:ysac020. [PMID: 36267953 PMCID: PMC9569155 DOI: 10.1093/synbio/ysac020] [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: 12/09/2021] [Revised: 07/16/2022] [Accepted: 09/29/2022] [Indexed: 11/16/2022] Open
Abstract
Genetic circuits are subject to variability due to cellular and compositional contexts. Cells face changing internal states and environments, the cellular context, to which they sense and respond by changing their gene expression and growth rates. Furthermore, each gene in a genetic circuit operates in a compositional context of genes which may interact with each other and the host cell in complex ways. The context of genetic circuits can, therefore, change gene expression and growth rates, and measuring their dynamics is essential to understanding natural and synthetic regulatory networks that give rise to functional phenotypes. However, reconstruction of microbial gene expression and growth rate profiles from typical noisy measurements of cell populations is difficult due to the effects of noise at low cell densities among other factors. We present here a method for the estimation of dynamic microbial gene expression rates and growth rates from noisy measurement data. Compared to the current state-of-the-art, our method significantly reduced the mean squared error of reconstructions from simulated data of growth and gene expression rates, improving the estimation of timing and magnitude of relevant shapes of profiles. We applied our method to characterize a triple-reporter plasmid library combining multiple transcription units in different compositional and cellular contexts in Escherichia coli. Our analysis reveals cellular and compositional context effects on microbial growth and gene expression rate dynamics and suggests a method for the dynamic ratiometric characterization of constitutive promoters relative to an in vivo reference.
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Affiliation(s)
- Gonzalo Vidal
- Institute for Biological and Medical Engineering, Schools of Engineering, Biology and Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- Interdisciplinary Computing and Complex BioSystems (ICOS) Research Group, School of Computing, Newcastle University, Newcastle Upon Tyne, UK
| | - Carolus Vitalis
- Institute for Biological and Medical Engineering, Schools of Engineering, Biology and Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Macarena Muñoz Silva
- Institute for Biological and Medical Engineering, Schools of Engineering, Biology and Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carlos Castillo-Passi
- Institute for Biological and Medical Engineering, Schools of Engineering, Biology and Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- School of Biomedical Engineering and Imaging Sciences, King’s College London, St Thomas’ Hospital, London, UK
- Millennium Institute for Intelligent Healthcare Engineering (iHEALTH), Santiago, Chile
| | - Guillermo Yáñez Feliú
- Interdisciplinary Computing and Complex BioSystems (ICOS) Research Group, School of Computing, Newcastle University, Newcastle Upon Tyne, UK
- Department of Chemical and Bioprocess Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Fernán Federici
- Institute for Biological and Medical Engineering, Schools of Engineering, Biology and Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- ANID – Millennium Science Initiative Program, Millennium Institute for Integrative Biology (iBio) & FONDAP Center for Genome Regulation, Santiago, Chile
| | - Timothy J Rudge
- Interdisciplinary Computing and Complex BioSystems (ICOS) Research Group, School of Computing, Newcastle University, Newcastle Upon Tyne, UK
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17
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Pfotenhauer AC, Occhialini A, Nguyen MA, Scott H, Dice LT, Harbison SA, Li L, Reuter DN, Schimel TM, Stewart CN, Beal J, Lenaghan SC. Building the Plant SynBio Toolbox through Combinatorial Analysis of DNA Regulatory Elements. ACS Synth Biol 2022; 11:2741-2755. [PMID: 35901078 PMCID: PMC9396662 DOI: 10.1021/acssynbio.2c00147] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
While the installation of complex genetic circuits in
microorganisms
is relatively routine, the synthetic biology toolbox is severely limited
in plants. Of particular concern is the absence of combinatorial analysis
of regulatory elements, the long design-build-test cycles associated
with transgenic plant analysis, and a lack of naming standardization
for cloning parts. Here, we use previously described plant regulatory
elements to design, build, and test 91 transgene cassettes for relative
expression strength. Constructs were transiently transfected into Nicotiana benthamiana leaves and expression of a
fluorescent reporter was measured from plant canopies, leaves, and
protoplasts isolated from transfected plants. As anticipated, a dynamic
level of expression was achieved from the library, ranging from near
undetectable for the weakest cassette to a ∼200-fold increase
for the strongest. Analysis of expression levels in plant canopies,
individual leaves, and protoplasts were correlated, indicating that
any of the methods could be used to evaluate regulatory elements in
plants. Through this effort, a well-curated 37-member part library
of plant regulatory elements was characterized, providing the necessary
data to standardize construct design for precision metabolic engineering
in plants.
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Affiliation(s)
- Alexander C Pfotenhauer
- Department of Food Science, University of Tennessee Knoxville, 102 Food Safety and Processing Building 2600 River Dr., Knoxville, Tennessee 37996, United States.,Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, Tennessee 37996, United States
| | - Alessandro Occhialini
- Department of Food Science, University of Tennessee Knoxville, 102 Food Safety and Processing Building 2600 River Dr., Knoxville, Tennessee 37996, United States.,Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, Tennessee 37996, United States
| | - Mary-Anne Nguyen
- Department of Food Science, University of Tennessee Knoxville, 102 Food Safety and Processing Building 2600 River Dr., Knoxville, Tennessee 37996, United States.,Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, Tennessee 37996, United States
| | - Helen Scott
- Intelligent Software and Systems, Raytheon BBN Technologies, Cambridge, Massachusetts 02138, United States
| | - Lezlee T Dice
- Department of Food Science, University of Tennessee Knoxville, 102 Food Safety and Processing Building 2600 River Dr., Knoxville, Tennessee 37996, United States.,Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, Tennessee 37996, United States
| | - Stacee A Harbison
- Department of Food Science, University of Tennessee Knoxville, 102 Food Safety and Processing Building 2600 River Dr., Knoxville, Tennessee 37996, United States.,Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, Tennessee 37996, United States
| | - Li Li
- Department of Food Science, University of Tennessee Knoxville, 102 Food Safety and Processing Building 2600 River Dr., Knoxville, Tennessee 37996, United States.,Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, Tennessee 37996, United States
| | - D Nikki Reuter
- Department of Food Science, University of Tennessee Knoxville, 102 Food Safety and Processing Building 2600 River Dr., Knoxville, Tennessee 37996, United States.,Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, Tennessee 37996, United States
| | - Tayler M Schimel
- Department of Food Science, University of Tennessee Knoxville, 102 Food Safety and Processing Building 2600 River Dr., Knoxville, Tennessee 37996, United States.,Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, Tennessee 37996, United States
| | - C Neal Stewart
- Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, Tennessee 37996, United States.,Department of Plant Sciences, University of Tennessee Knoxville, 2431 Joe Johnson Dr., Knoxville, Tennessee 37996, United States
| | - Jacob Beal
- Intelligent Software and Systems, Raytheon BBN Technologies, Cambridge, Massachusetts 02138, United States
| | - Scott C Lenaghan
- Department of Food Science, University of Tennessee Knoxville, 102 Food Safety and Processing Building 2600 River Dr., Knoxville, Tennessee 37996, United States.,Center for Agricultural Synthetic Biology, University of Tennessee Institute of Agriculture, Knoxville, Tennessee 37996, United States
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18
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Beal J, Telmer CA, Vignoni A, Boada Y, Baldwin GS, Hallett L, Lee T, Selvarajah V, Billerbeck S, Brown B, Cai GN, Cai L, Eisenstein E, Kiga D, Ross D, Alperovich N, Sprent N, Thompson J, Young EM, Endy D, Haddock-Angelli T. Multicolor Plate Reader Fluorescence Calibration. Synth Biol (Oxf) 2022; 7:ysac010. [PMID: 35949424 PMCID: PMC9357555 DOI: 10.1093/synbio/ysac010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 06/15/2022] [Accepted: 07/20/2022] [Indexed: 11/14/2022] Open
Abstract
Plate readers are commonly used to measure cell growth and fluorescence, yet the utility and reproducibility of plate reader data is limited by the fact that it is typically reported in arbitrary or relative units. We have previously established a robust serial dilution protocol for calibration of plate reader measurements of absorbance to estimated bacterial cell count and for green fluorescence from proteins expressed in bacterial cells to molecules of equivalent fluorescein. We now extend these protocols to calibration of red fluorescence to the sulforhodamine-101 fluorescent dye and blue fluorescence to Cascade Blue. Evaluating calibration efficacy via an interlaboratory study, we find that these calibrants do indeed provide comparable precision to the prior calibrants and that they enable effective cross-laboratory comparison of measurements of red and blue fluorescence from proteins expressed in bacterial cells.
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Affiliation(s)
- Jacob Beal
- Intelligent Software and Systems, Raytheon BBN Technologies , 10 Moulton Street, Cambridge 02138, MA, USA
| | - Cheryl A Telmer
- Department of Biological Sciences, Carnegie Mellon University , 4400 Fifth Avenue, Pittsburgh 15213, PA, USA
| | - Alejandro Vignoni
- Synthetic Biology and Biosystems Control Group, Instituto de Automatica e Informatica Industrial, Universitat Politecnica de Valencia , Camino de Vera s/n, Valencia 46022, Spain
| | - Yadira Boada
- Synthetic Biology and Biosystems Control Group, Instituto de Automatica e Informatica Industrial, Universitat Politecnica de Valencia , Camino de Vera s/n, Valencia 46022, Spain
| | - Geoff S Baldwin
- Department of Life Sciences, Imperial College London , South Kensington Campus, Exhibition Road, London SW7 2AZ, UK
| | - Liam Hallett
- Department of Life Sciences, Imperial College London , South Kensington Campus, Exhibition Road, London SW7 2AZ, UK
| | - Taeyang Lee
- Department of Life Sciences, Imperial College London , South Kensington Campus, Exhibition Road, London SW7 2AZ, UK
| | | | - Sonja Billerbeck
- Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Nijenborgh 7, Groningen 9747 AG, The Netherlands
| | - Bradley Brown
- School of Engineering, Newcastle University , Devonshire Building, Devonshire Terrace, NE1 7RU Newcastle Upon Tyne, UK
| | - Guo-nan Cai
- School of Life Sciences, Fudan University , 220 Handan Road, Shanghai 200433, China
| | - Liang Cai
- School of Life Sciences, Fudan University , 220 Handan Road, Shanghai 200433, China
| | - Edward Eisenstein
- Fischell Department of Bioengineering, University of Maryland Institute of Bioscience and Biotechnology Research, , 9600 Gudelsky Drive, Rockville 20850, MD, USA
| | - Daisuke Kiga
- School of Advanced Science and Engineering, Waseda University , 2-2 Wakamatsu Cho, Totsukamachi, Shinjuku City 169-8050, Tokyo, Japan
| | - David Ross
- Material Measurement Laboratory, National Institute of Standards and Technology , 100 Bureau Dr., Gaithersburg 20899, MD, USA
| | - Nina Alperovich
- Material Measurement Laboratory, National Institute of Standards and Technology , 100 Bureau Dr., Gaithersburg 20899, MD, USA
| | - Noah Sprent
- Department of Chemical Engineering, Imperial College London , South Kensington Campus, Exhibition Road, London SW7 2AZ, UK
| | - Jaclyn Thompson
- Chemical Engineering, Worcester Polytechnic Institute , 100 Institute Road, Worcester 01609-2280, MA, USA
| | - Eric M Young
- Chemical Engineering, Worcester Polytechnic Institute , 100 Institute Road, Worcester 01609-2280, MA, USA
| | - Drew Endy
- Bioengineering, Stanford University , 443 Via Ortega, Stanford 94305, CA, USA
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19
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Vidal G, Vidal-Céspedes C, Rudge TJ. LOICA: Integrating Models with Data for Genetic Network Design Automation. ACS Synth Biol 2022; 11:1984-1990. [PMID: 35507566 PMCID: PMC9127962 DOI: 10.1021/acssynbio.1c00603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Indexed: 11/30/2022]
Abstract
Genetic design automation tools are necessary to expand the scale and complexity of possible synthetic genetic networks. These tools are enabled by abstraction of a hierarchy of standardized components and devices. Abstracted elements must be parametrized from data derived from relevant experiments, and these experiments must be related to the part composition of the abstract components. Here we present Logical Operators for Integrated Cell Algorithms (LOICA), a Python package for designing, modeling, and characterizing genetic networks based on a simple object-oriented design abstraction. LOICA uses classes to represent different biological and experimental components, which generate models through their interactions. These models can be parametrized by direct connection to data contained in Flapjack so that abstracted components of designs can characterize themselves. Models can be simulated using continuous or stochastic methods and the data published and managed using Flapjack. LOICA also outputs SBOL3 descriptions and generates graph representations of genetic network designs.
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Affiliation(s)
- Gonzalo Vidal
- Institute
for Biological and Medical Engineering, Schools of Engineering, Biology,
and Medicine, Pontificia Universidad Católica
de Chile, Santiago 7820244, Chile
- Interdisciplinary
Computing and Complex BioSystems (ICOS) Research Group, School of
Computing, Newcastle University, Newcastle upon Tyne NE1
7RU, U.K.
| | - Carlos Vidal-Céspedes
- Institute
for Biological and Medical Engineering, Schools of Engineering, Biology,
and Medicine, Pontificia Universidad Católica
de Chile, Santiago 7820244, Chile
| | - Timothy J. Rudge
- Interdisciplinary
Computing and Complex BioSystems (ICOS) Research Group, School of
Computing, Newcastle University, Newcastle upon Tyne NE1
7RU, U.K.
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20
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Putzeys L, Boon M, Lammens EM, Kuznedelov K, Severinov K, Lavigne R. Development of ONT-cappable-seq to unravel the transcriptional landscape of Pseudomonas phages. Comput Struct Biotechnol J 2022; 20:2624-2638. [PMID: 35685363 PMCID: PMC9163698 DOI: 10.1016/j.csbj.2022.05.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/16/2022] [Accepted: 05/16/2022] [Indexed: 11/28/2022] Open
Affiliation(s)
- Leena Putzeys
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Leuven 3001, Belgium
| | - Maarten Boon
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Leuven 3001, Belgium
| | - Eveline-Marie Lammens
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Leuven 3001, Belgium
| | | | | | - Rob Lavigne
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Leuven 3001, Belgium
- Corresponding author.
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21
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Beal J, Teague B, Sexton JT, Castillo-Hair S, DeLateur NA, Samineni M, Tabor JJ, Weiss R. Meeting Measurement Precision Requirements for Effective Engineering of Genetic Regulatory Networks. ACS Synth Biol 2022; 11:1196-1207. [PMID: 35156365 DOI: 10.1021/acssynbio.1c00488] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reliable, predictable engineering of cellular behavior is one of the key goals of synthetic biology. As the field matures, biological engineers will become increasingly reliant on computer models that allow for the rapid exploration of design space prior to the more costly construction and characterization of candidate designs. The efficacy of such models, however, depends on the accuracy of their predictions, the precision of the measurements used to parametrize the models, and the tolerance of biological devices for imperfections in modeling and measurement. To better understand this relationship, we have derived an Engineering Error Inequality that provides a quantitative mathematical bound on the relationship between predictability of results, model accuracy, measurement precision, and device characteristics. We apply this relation to estimate measurement precision requirements for engineering genetic regulatory networks given current model and device characteristics, recommending a target standard deviation of 1.5-fold. We then compare these requirements with the results of an interlaboratory study to validate that these requirements can be met via flow cytometry with matched instrument channels and an independent calibrant. On the basis of these results, we recommend a set of best practices for quality control of flow cytometry data and discuss how these might be extended to other measurement modalities and applied to support further development of genetic regulatory network engineering.
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Affiliation(s)
- Jacob Beal
- Raytheon BBN Technologies, Cambridge, Massachusetts 02138, United States
| | - Brian Teague
- Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - John T. Sexton
- Department of Bioengineering, Rice University, Houston, Texas 77005, United States
| | | | - Nicholas A. DeLateur
- Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Meher Samineni
- Raytheon BBN Technologies, Cambridge, Massachusetts 02138, United States
| | - Jeffrey J. Tabor
- Department of Bioengineering, Rice University, Houston, Texas 77005, United States
| | - Ron Weiss
- Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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22
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Du R, Yang D, Yin X. Rapid Detection of Three Common Bacteria Based on Fluorescence Spectroscopy. SENSORS (BASEL, SWITZERLAND) 2022; 22:s22031168. [PMID: 35161912 PMCID: PMC8840577 DOI: 10.3390/s22031168] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/29/2022] [Accepted: 01/31/2022] [Indexed: 05/19/2023]
Abstract
As an important part of environmental water quality monitoring, efficient bacterial detection has attracted widespread attention. Among them, LIF (laser-induced fluorescence) technology has the characteristics of high efficiency and sensitivity for bacterial detection. To simplify the experimental process of bacterial detection, fluorescence emission spectra of E. coli (Escherichia coli) and its deactivated controls, K. pneumoniae (Klebsiella pneumoniae) and S. aureus (Staphylococcus aureus), were analyzed with fluorescence excitation by a 266 nm laser. By analyzing the results, it was found that the dominant fluorescence peaks of bacterial solutions at 335~350 nm were contributed by tryptophan, and the subfluorescence peaks at 515.9 nm were contributed by flavin; besides, K. pneumoniae and S. aureus had their own fluoresces characteristics, such as tyrosine contributing to sub-fluorescence peaks at 300 nm. The three species of bacteria can be differentiated with whole fluorescence spectrum by statistically analysis (p < 0.05), for various concentrations of aromatic amino acids and flavin in different bacteria. The experimental results also proved that the inactivation operation did not alter the spectral properties of E. coli. The indexes of fluorescence intensity and FIR (fluorescence intensity ratio, I335~350/I515.9) can be used to retrieve the bacteria concentration as well as for bacteria differentiation using the index of slopes. The detection limit of bacteria is less than ~105 cell/mL using laser induced fluorescence methods in the paper. The study demonstrated the rapid detection capability of the LIF bacterial detection system and its great potential for rapid quantitative analysis of bacteria. This may bring new insight into the detection of common bacteria in water in situ.
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Affiliation(s)
- Ranran Du
- Guangdong Key Lab of Ocean Remote Sensing, State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; (R.D.); (X.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dingtian Yang
- Guangdong Key Lab of Ocean Remote Sensing, State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; (R.D.); (X.Y.)
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China
- Correspondence:
| | - Xiaoqing Yin
- Guangdong Key Lab of Ocean Remote Sensing, State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; (R.D.); (X.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
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Beabout K, Bernhards CB, Thakur M, Turner KB, Cole SD, Walper SA, Chávez JL, Lux MW. Optimization of Heavy Metal Sensors Based on Transcription Factors and Cell-Free Expression Systems. ACS Synth Biol 2021; 10:3040-3054. [PMID: 34723503 DOI: 10.1021/acssynbio.1c00331] [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: 02/03/2023]
Abstract
Many bacterial mechanisms for highly specific and sensitive detection of heavy metals and other hazards have been reengineered to serve as sensors. In some cases, these sensors have been implemented in cell-free expression systems, enabling easier design optimization and deployment in low-resource settings through lyophilization. Here, we apply the advantages of cell-free expression systems to optimize sensors based on three separate bacterial response mechanisms for arsenic, cadmium, and mercury. We achieved detection limits below the World Health Organization-recommended levels for arsenic and mercury and below the short-term US Military Exposure Guideline levels for all three. The optimization of each sensor was approached differently, leading to observations useful for the development of future sensors: (1) there can be a strong dependence of specificity on the particular cell-free expression system used, (2) tuning of relative concentrations of the sensing and reporter elements improves sensitivity, and (3) sensor performance can vary significantly with linear vs plasmid DNA. In addition, we show that simply combining DNA for the three sensors into a single reaction enables detection of each target heavy metal without any further optimization. This combined approach could lead to sensors that detect a range of hazards at once, such as a panel of water contaminants or all known variants of a target virus. For low-resource settings, such "all-hazard" sensors in a cheap, easy-to-use format could have high utility.
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Affiliation(s)
- Kathryn Beabout
- UES, Inc., Dayton, Ohio 45432, United States
- Air Force Research Laboratory, 711th Human Performance Wing, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Casey B. Bernhards
- Excet, Inc., 6225 Brandon Avenue #360, Springfield, Virginia 22150, United States
- U.S. Army Combat Capabilities Development Command Chemical Biological Center, 8198 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
| | - Meghna Thakur
- Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375, United States
- College of Science, George Mason University, Fairfax, Virginia 22030, United States
| | - Kendrick B. Turner
- Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375, United States
| | - Stephanie D. Cole
- U.S. Army Combat Capabilities Development Command Chemical Biological Center, 8198 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
| | - Scott A. Walper
- Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375, United States
| | - Jorge L. Chávez
- Air Force Research Laboratory, 711th Human Performance Wing, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Matthew W. Lux
- U.S. Army Combat Capabilities Development Command Chemical Biological Center, 8198 Blackhawk Road, Aberdeen Proving Ground, Maryland 21010, United States
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25
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Lammens EM, Boon M, Grimon D, Briers Y, Lavigne R. SEVAtile: a standardised DNA assembly method optimised for Pseudomonas. Microb Biotechnol 2021; 15:370-386. [PMID: 34651450 PMCID: PMC8719830 DOI: 10.1111/1751-7915.13922] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/29/2021] [Accepted: 09/01/2021] [Indexed: 11/25/2022] Open
Abstract
To meet the needs of synthetic biologists, DNA assembly methods have transformed from simple 'cut-and-paste' procedures to highly advanced, standardised assembly techniques. Implementing these standardised DNA assembly methods in biotechnological research conducted in non-model hosts, including Pseudomonas putida and Pseudomonas aeruginosa, could greatly benefit reproducibility and predictability of experimental results. SEVAtile is a Type IIs-based assembly approach, which enables the rapid and standardised assembly of genetic parts - or tiles - to create genetic circuits in the established SEVA-vector backbone. Contrary to existing DNA assembly methods, SEVAtile is an easy and straightforward method, which is compatible with any vector, both SEVA- and non-SEVA. To prove the efficiency of the SEVAtile method, a three-vector system was successfully generated to independently co-express three different proteins in P. putida and P. aeruginosa. More specifically, one of the vectors, pBGDes, enables genomic integration of assembled circuits in the Tn7 landing site, while self-replicatory vectors pSTDesX and pSTDesR enable inducible expression from the XylS/Pm and RhaRS/PrhaB expression systems, respectively. Together, we hope these vector systems will support research in both the microbial SynBio and Pseudomonas field.
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Affiliation(s)
- Eveline-Marie Lammens
- Department of Biosystems, Laboratory of Gene Technology, KULeuven, Kasteelpark Arenberg 21 Box 2462, Leuven, 3001, Belgium
| | - Maarten Boon
- Department of Biosystems, Laboratory of Gene Technology, KULeuven, Kasteelpark Arenberg 21 Box 2462, Leuven, 3001, Belgium
| | - Dennis Grimon
- Laboratory of Applied Biotechnology, Department of Biotechnology, Ghent University, Valentin Vaerwyckweg 1, Gent, 9000, Belgium
| | - Yves Briers
- Laboratory of Applied Biotechnology, Department of Biotechnology, Ghent University, Valentin Vaerwyckweg 1, Gent, 9000, Belgium
| | - Rob Lavigne
- Department of Biosystems, Laboratory of Gene Technology, KULeuven, Kasteelpark Arenberg 21 Box 2462, Leuven, 3001, Belgium
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Ihssen J, Faccio G, Yao C, Sirec T, Spitz U. Fluorogenic in vitro activity assay for the main protease M pro from SARS-CoV-2 and its adaptation to the identification of inhibitors. STAR Protoc 2021; 2:100793. [PMID: 34423318 PMCID: PMC8367757 DOI: 10.1016/j.xpro.2021.100793] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
This protocol describes an in vitro fluorogenic assay to measure the proteolytic activity and identify inhibitors of Mpro, the main protease produced by SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2). Studies to identify potential inhibitors of Mpro mainly rely on in silico molecular dynamics simulations or on FRET (Fluorescence Resonance Energy Transfer) substrates. The protocol is based on an aminomethyl coumarin substrate. High sensitivity, specificity, and an easily detectable fluorescent read-out are the advantages offered by this rapid assay, which allows high throughput screening of new Mpro inhibitors. Mpro is the main protease produced by SARS-CoV-2 An in vitro fluorogenic assay for the measurement of the proteolytic activity of Mpro An in vitro fluorogenic assay for the inhibitor screening of Mpro High sensitivity, specificity, and an easily detectable fluorescent read-out
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Affiliation(s)
- Julien Ihssen
- Biosynth Carbosynth, Rietlistrasse 4, 9422 Staad, Switzerland
| | - Greta Faccio
- Biosynth Carbosynth, Rietlistrasse 4, 9422 Staad, Switzerland
| | - Chunyan Yao
- Biosynth Carbosynth, Rietlistrasse 4, 9422 Staad, Switzerland
| | - Teja Sirec
- Biosynth Carbosynth, Rietlistrasse 4, 9422 Staad, Switzerland
| | - Urs Spitz
- Biosynth Carbosynth, Rietlistrasse 4, 9422 Staad, Switzerland
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Ciurkot K, Gorochowski TE, Roubos JA, Verwaal R. Efficient multiplexed gene regulation in Saccharomyces cerevisiae using dCas12a. Nucleic Acids Res 2021; 49:7775-7790. [PMID: 34197613 PMCID: PMC8287914 DOI: 10.1093/nar/gkab529] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 06/02/2021] [Accepted: 06/09/2021] [Indexed: 12/27/2022] Open
Abstract
CRISPR Cas12a is an RNA-programmable endonuclease particularly suitable for gene regulation. This is due to its preference for T-rich PAMs that allows it to more easily target AT-rich promoter sequences, and built-in RNase activity which can process a single CRISPR RNA array encoding multiple spacers into individual guide RNAs (gRNAs), thereby simplifying multiplexed gene regulation. Here, we develop a flexible dCas12a-based CRISPRi system for Saccharomyces cerevisiae and systematically evaluate its design features. This includes the role of the NLS position, use of repression domains, and the position of the gRNA target. Our optimal system is comprised of dCas12a E925A with a single C-terminal NLS and a Mxi1 or a MIG1 repression domain, which enables up to 97% downregulation of a reporter gene. We also extend this system to allow for inducible regulation via an RNAP II-controlled promoter, demonstrate position-dependent effects in crRNA arrays, and use multiplexed regulation to stringently control a heterologous β-carotene pathway. Together these findings offer valuable insights into the design constraints of dCas12a-based CRISPRi and enable new avenues for flexible and efficient gene regulation in S. cerevisiae.
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Affiliation(s)
- Klaudia Ciurkot
- DSM Biotechnology Center, Delft 2613 AX, The Netherlands.,Department of Chemistry, University of Hamburg, Hamburg 20146, Germany
| | - Thomas E Gorochowski
- School of Biological Sciences, University of Bristol, Tyndall Avenue, Bristol BS8 1TQ, UK
| | | | - René Verwaal
- DSM Biotechnology Center, Delft 2613 AX, The Netherlands
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28
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Power AL, Barber DG, Groenhof SRM, Wagley S, Liu P, Parker DA, Love J. The Application of Imaging Flow Cytometry for Characterisation and Quantification of Bacterial Phenotypes. Front Cell Infect Microbiol 2021; 11:716592. [PMID: 34368019 PMCID: PMC8335544 DOI: 10.3389/fcimb.2021.716592] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/08/2021] [Indexed: 12/25/2022] Open
Abstract
Bacteria modify their morphology in response to various factors including growth stage, nutrient availability, predation, motility and long-term survival strategies. Morphological changes may also be associated with specific physiological phenotypes such as the formation of dormant or persister cells in a “viable but non-culturable” (VBNC) state which frequently display different shapes and size compared to their active counterparts. Such dormancy phenotypes can display various degrees of tolerance to antibiotics and therefore a detailed understanding of these phenotypes is crucial for combatting chronic infections and associated diseases. Cell shape and size are therefore more than simple phenotypic characteristics; they are important physiological properties for understanding bacterial life-strategies and pathologies. However, quantitative studies on the changes to cell morphologies during bacterial growth, persister cell formation and the VBNC state are few and severely constrained by current limitations in the most used investigative techniques of flow cytometry (FC) and light or electron microscopy. In this study, we applied high-throughput Imaging Flow Cytometry (IFC) to characterise and quantify, at single-cell level and over time, the phenotypic heterogeneity and morphological changes in cultured populations of four bacterial species, Bacillus subtilis, Lactiplantibacillus plantarum, Pediococcus acidilactici and Escherichia coli. Morphologies in relation to growth stage and stress responses, cell integrity and metabolic activity were analysed. Additionally, we were able to identify and morphologically classify dormant cell phenotypes such as VBNC cells and monitor the resuscitation of persister cells in Escherichia coli following antibiotic treatment. We therefore demonstrate that IFC, with its high-throughput data collection and image capture capabilities, provides a platform by which a detailed understanding of changes in bacterial phenotypes and their physiological implications may be accurately monitored and quantified, leading to a better understanding of the role of phenotypic heterogeneity in the dynamic microbiome.
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Affiliation(s)
- Ann L Power
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Daniel G Barber
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Sophie R M Groenhof
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Sariqa Wagley
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Ping Liu
- Shell International Exploration & Production Inc., Westhollow Technology Center, Houston, TX, United States
| | - David A Parker
- Shell International Exploration & Production Inc., Westhollow Technology Center, Houston, TX, United States
| | - John Love
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
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29
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McCarthy J. Engineering and standardization of posttranscriptional biocircuitry in Saccharomyces cerevisiae. Integr Biol (Camb) 2021; 13:210-220. [PMID: 34270725 DOI: 10.1093/intbio/zyab013] [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: 04/27/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 11/14/2022]
Abstract
This short review considers to what extent posttranscriptional steps of gene expression can provide the basis for novel control mechanisms and procedures in synthetic biology and biotechnology. The term biocircuitry is used here to refer to functionally connected components comprising DNA, RNA or proteins. The review begins with an overview of the diversity of devices being developed and then considers the challenges presented by trying to engineer more scaled-up systems. While the engineering of RNA-based and protein-based circuitry poses new challenges, the resulting 'toolsets' of components and novel mechanisms of operation will open up multiple new opportunities for synthetic biology. However, agreed procedures for standardization will need to be placed at the heart of this expanding field if the full potential benefits are to be realized.
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Affiliation(s)
- John McCarthy
- Warwick Integrative Synthetic Biology Centre (WISB) and School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
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30
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Comparative analysis of three studies measuring fluorescence from engineered bacterial genetic constructs. PLoS One 2021; 16:e0252263. [PMID: 34097703 PMCID: PMC8183995 DOI: 10.1371/journal.pone.0252263] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/11/2021] [Indexed: 11/19/2022] Open
Abstract
Reproducibility is a key challenge of synthetic biology, but the foundation of reproducibility is only as solid as the reference materials it is built upon. Here we focus on the reproducibility of fluorescence measurements from bacteria transformed with engineered genetic constructs. This comparative analysis comprises three large interlaboratory studies using flow cytometry and plate readers, identical genetic constructs, and compatible unit calibration protocols. Across all three studies, we find similarly high precision in the calibrants used for plate readers. We also find that fluorescence measurements agree closely across the flow cytometry results and two years of plate reader results, with an average standard deviation of 1.52-fold, while the third year of plate reader results are consistently shifted by more than an order of magnitude, with an average shift of 28.9-fold. Analyzing possible sources of error indicates this shift is due to incorrect preparation of the fluorescein calibrant. These findings suggest that measuring fluorescence from engineered constructs is highly reproducible, but also that there is a critical need for access to quality controlled fluorescent calibrants for plate readers.
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Rammohan J, Lund SP, Alperovich N, Paralanov V, Strychalski EA, Ross D. Comparison of bias and resolvability in single-cell and single-transcript methods. Commun Biol 2021; 4:659. [PMID: 34079048 PMCID: PMC8172639 DOI: 10.1038/s42003-021-02138-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 04/16/2021] [Indexed: 11/17/2022] Open
Abstract
Single-cell and single-transcript measurement methods have elevated our ability to understand and engineer biological systems. However, defining and comparing performance between methods remains a challenge, in part due to the confounding effects of experimental variability. Here, we propose a generalizable framework for performing multiple methods in parallel using split samples, so that experimental variability is shared between methods. We demonstrate the utility of this framework by performing 12 different methods in parallel to measure the same underlying reference system for cellular response. We compare method performance using quantitative evaluations of bias and resolvability. We attribute differences in method performance to steps along the measurement process such as sample preparation, signal detection, and choice of measurand. Finally, we demonstrate how this framework can be used to benchmark different methods for single-transcript detection. The framework we present here provides a practical way to compare performance of any methods.
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Affiliation(s)
- Jayan Rammohan
- National Institute of Standards and Technology, Gaithersburg, MD, USA.
| | - Steven P Lund
- National Institute of Standards and Technology, Gaithersburg, MD, USA
| | - Nina Alperovich
- National Institute of Standards and Technology, Gaithersburg, MD, USA
| | - Vanya Paralanov
- National Institute of Standards and Technology, Gaithersburg, MD, USA
| | | | - David Ross
- National Institute of Standards and Technology, Gaithersburg, MD, USA.
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32
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Pedone E, de Cesare I, Zamora-Chimal CG, Haener D, Postiglione L, La Regina A, Shannon B, Savery NJ, Grierson CS, di Bernardo M, Gorochowski TE, Marucci L. Cheetah: A Computational Toolkit for Cybergenetic Control. ACS Synth Biol 2021; 10:979-989. [PMID: 33904719 DOI: 10.1021/acssynbio.0c00463] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Advances in microscopy, microfluidics, and optogenetics enable single-cell monitoring and environmental regulation and offer the means to control cellular phenotypes. The development of such systems is challenging and often results in bespoke setups that hinder reproducibility. To address this, we introduce Cheetah, a flexible computational toolkit that simplifies the integration of real-time microscopy analysis with algorithms for cellular control. Central to the platform is an image segmentation system based on the versatile U-Net convolutional neural network. This is supplemented with functionality to robustly count, characterize, and control cells over time. We demonstrate Cheetah's core capabilities by analyzing long-term bacterial and mammalian cell growth and by dynamically controlling protein expression in mammalian cells. In all cases, Cheetah's segmentation accuracy exceeds that of a commonly used thresholding-based method, allowing for more accurate control signals to be generated. Availability of this easy-to-use platform will make control engineering techniques more accessible and offer new ways to probe and manipulate living cells.
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Affiliation(s)
- Elisa Pedone
- Department of Engineering Mathematics, University of Bristol, Ada Lovelace Building, University Walk, BS8 1TW Bristol, United Kingdom
- School of Cellular and Molecular Medicine, University of Bristol, Biomedical Sciences Building, University Walk, BS8 1TD Bristol, United Kingdom
| | - Irene de Cesare
- Department of Engineering Mathematics, University of Bristol, Ada Lovelace Building, University Walk, BS8 1TW Bristol, United Kingdom
| | - Criseida G. Zamora-Chimal
- Department of Engineering Mathematics, University of Bristol, Ada Lovelace Building, University Walk, BS8 1TW Bristol, United Kingdom
- BrisSynBio, Life Sciences Building, Tyndall Avenue, BS8 1TQ Bristol, United Kingdom
| | - David Haener
- Department of Engineering Mathematics, University of Bristol, Ada Lovelace Building, University Walk, BS8 1TW Bristol, United Kingdom
| | - Lorena Postiglione
- Department of Engineering Mathematics, University of Bristol, Ada Lovelace Building, University Walk, BS8 1TW Bristol, United Kingdom
| | - Antonella La Regina
- Department of Engineering Mathematics, University of Bristol, Ada Lovelace Building, University Walk, BS8 1TW Bristol, United Kingdom
- School of Cellular and Molecular Medicine, University of Bristol, Biomedical Sciences Building, University Walk, BS8 1TD Bristol, United Kingdom
| | - Barbara Shannon
- BrisSynBio, Life Sciences Building, Tyndall Avenue, BS8 1TQ Bristol, United Kingdom
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, BS8 1TD Bristol, United Kingdom
| | - Nigel J. Savery
- BrisSynBio, Life Sciences Building, Tyndall Avenue, BS8 1TQ Bristol, United Kingdom
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, BS8 1TD Bristol, United Kingdom
| | - Claire S. Grierson
- BrisSynBio, Life Sciences Building, Tyndall Avenue, BS8 1TQ Bristol, United Kingdom
- School of Biological Sciences, University of Bristol, Tyndall Avenue, BS8 1TQ Bristol, United Kingdom
| | - Mario di Bernardo
- Department of Engineering Mathematics, University of Bristol, Ada Lovelace Building, University Walk, BS8 1TW Bristol, United Kingdom
- BrisSynBio, Life Sciences Building, Tyndall Avenue, BS8 1TQ Bristol, United Kingdom
- Department of EE and ICT, University of Naples Federico II, Via Claudio 21, 80125 Naples, Italy
| | - Thomas E. Gorochowski
- BrisSynBio, Life Sciences Building, Tyndall Avenue, BS8 1TQ Bristol, United Kingdom
- School of Biological Sciences, University of Bristol, Tyndall Avenue, BS8 1TQ Bristol, United Kingdom
| | - Lucia Marucci
- Department of Engineering Mathematics, University of Bristol, Ada Lovelace Building, University Walk, BS8 1TW Bristol, United Kingdom
- School of Cellular and Molecular Medicine, University of Bristol, Biomedical Sciences Building, University Walk, BS8 1TD Bristol, United Kingdom
- BrisSynBio, Life Sciences Building, Tyndall Avenue, BS8 1TQ Bristol, United Kingdom
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Setting Up an Automated Biomanufacturing Laboratory. Methods Mol Biol 2021; 2229:137-155. [PMID: 33405219 DOI: 10.1007/978-1-0716-1032-9_5] [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: 03/29/2023]
Abstract
Laboratory automation is a key enabling technology for genetic engineering that can lead to higher throughput, more efficient and accurate experiments, better data management and analysis, decrease in the DBT (Design, Build, and Test) cycle turnaround, increase of reproducibility, and savings in lab resources. Choosing the correct framework among so many options available in terms of software, hardware, and skills needed to operate them is crucial for the success of any automation project. This chapter explores the multiple aspects to be considered for the solid development of a biofoundry project including available software and hardware tools, resources, strategies, partnerships, and collaborations in the field needed to speed up the translation of research results to solve important society problems.
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Scheller L. Synthetic Receptors for Sensing Soluble Molecules with Mammalian Cells. Methods Mol Biol 2021; 2312:15-33. [PMID: 34228282 DOI: 10.1007/978-1-0716-1441-9_2] [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: 06/13/2023]
Abstract
Synthetic receptors control cell behavior in response to environmental stimuli for applications in basic research and cell therapy. However, the integration of synthetic receptors in unexplored contexts is cumbersome, especially for nonspecialist laboratories. Here, I provide a detailed protocol on how to use receptors of the generalized extracellular molecule sensor (GEMS) platform. GEMS is a modular receptor system that can be adapted to sense molecules of choice by using affinity domains that dimerize in response to the target. GEMS consist of an erythropoietin receptor scaffold that has been mutated to no longer bind to erythropoietin. N-terminal fusions with affinity domains, such as single chain variable fragments (scFvs), that bind to two epitopes on the same target activate the receptor. The intracellular receptor domain can be chosen from several signal transduction domains of single-pass transmembrane receptors to activate endogenous signaling pathways. As of now, GEMS have been used for sensing prostate specific antigen (PSA), the synthetic azo dye RR120, caffeine, nicotine, rapamycin, the SunTag peptide, and a de novo designed protein displaying two viral epitopes. The tested intracellular domains were derived from FGFR1, IL-6RB, and VEGFR2, and were used to drive transgene expression from reporter plasmids responsive to the endogenous transcription factors STAT3, NFAT, NF-κB, and a synthetic transcription factor activated by the MAPK pathway. In this protocol, I focus on transient transfections of HEK293T cells and include several general notes about cell handling. While the described methods are optimized for experiments with GEMS, most of the described techniques are general procedures to set up synthetic biology experiments in mammalian cell culture. I outline how to generate stable cell lines and share tips on how to adapt GEMS for new ligands. The main objective of this protocol is to make the GEMS technology accessible also to nonspecialist laboratories to facilitate the use of synthetic receptors in new research contexts.
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Affiliation(s)
- Leo Scheller
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
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35
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Young R, Haines M, Storch M, Freemont PS. Combinatorial metabolic pathway assembly approaches and toolkits for modular assembly. Metab Eng 2020; 63:81-101. [PMID: 33301873 DOI: 10.1016/j.ymben.2020.12.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 11/16/2020] [Accepted: 12/03/2020] [Indexed: 12/18/2022]
Abstract
Synthetic Biology is a rapidly growing interdisciplinary field that is primarily built upon foundational advances in molecular biology combined with engineering design principles such as modularity and interoperability. The field considers living systems as programmable at the genetic level and has been defined by the development of new platform technologies and methodological advances. A key concept driving the field is the Design-Build-Test-Learn cycle which provides a systematic framework for building new biological systems. One major application area for synthetic biology is biosynthetic pathway engineering that requires the modular assembly of different genetic regulatory elements and biosynthetic enzymes. In this review we provide an overview of modular DNA assembly and describe and compare the plethora of in vitro and in vivo assembly methods for combinatorial pathway engineering. Considerations for part design and methods for enzyme balancing are also presented, and we briefly discuss alternatives to intracellular pathway assembly including microbial consortia and cell-free systems for biosynthesis. Finally, we describe computational tools and automation for pathway design and assembly and argue that a deeper understanding of the many different variables of genetic design, pathway regulation and cellular metabolism will allow more predictive pathway design and engineering.
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Affiliation(s)
- Rosanna Young
- Department of Infectious Disease, Sir Alexander Fleming Building, South Kensington Campus, Imperial College London, SW7 2AZ, UK
| | - Matthew Haines
- Department of Infectious Disease, Sir Alexander Fleming Building, South Kensington Campus, Imperial College London, SW7 2AZ, UK
| | - Marko Storch
- Department of Infectious Disease, Sir Alexander Fleming Building, South Kensington Campus, Imperial College London, SW7 2AZ, UK; London Biofoundry, Imperial College Translation & Innovation Hub, London, W12 0BZ, UK
| | - Paul S Freemont
- Department of Infectious Disease, Sir Alexander Fleming Building, South Kensington Campus, Imperial College London, SW7 2AZ, UK; London Biofoundry, Imperial College Translation & Innovation Hub, London, W12 0BZ, UK; UK DRI Care Research and Technology Centre, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK.
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36
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Gilliot PA, Gorochowski TE. Sequencing enabling design and learning in synthetic biology. Curr Opin Chem Biol 2020; 58:54-62. [DOI: 10.1016/j.cbpa.2020.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/21/2020] [Accepted: 06/02/2020] [Indexed: 01/27/2023]
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37
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Fedorec AJ, Robinson CM, Wen KY, Barnes CP. FlopR: An Open Source Software Package for Calibration and Normalization of Plate Reader and Flow Cytometry Data. ACS Synth Biol 2020; 9:2258-2266. [PMID: 32854500 PMCID: PMC7506944 DOI: 10.1021/acssynbio.0c00296] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Indexed: 01/03/2023]
Abstract
The measurement of gene expression using fluorescence markers has been a cornerstone of synthetic biology for the past two decades. However, the use of arbitrary units has limited the usefulness of these data for many quantitative purposes. Calibration of fluorescence measurements from flow cytometry and plate reader spectrophotometry has been implemented previously, but the tools are disjointed. Here we pull together, and in some cases improve, extant methods into a single software tool, written as a package in the R statistical framework. The workflow is validated using Escherichia coli engineered to express green fluorescent protein (GFP) from a set of commonly used constitutive promoters. We then demonstrate the package's power by identifying the time evolution of distinct subpopulations of bacteria from bulk plate reader data, a task previously reliant on laborious flow cytometry or colony counting experiments. Along with standardized parts and experimental methods, the development and dissemination of usable tools for quantitative measurement and data analysis will benefit the synthetic biology community by improving interoperability.
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Affiliation(s)
- Alex J.
H. Fedorec
- Department
of Cell and Developmental Biology, University
College London, London WC1E 6BT, U.K.
| | - Clare M. Robinson
- Department
of Cell and Developmental Biology, University
College London, London WC1E 6BT, U.K.
| | - Ke Yan Wen
- Department
of Cell and Developmental Biology, University
College London, London WC1E 6BT, U.K.
| | - Chris P. Barnes
- Department
of Cell and Developmental Biology, University
College London, London WC1E 6BT, U.K.
- UCL
Genetics Institute, University College London, London WC1E 6BT, U.K.
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38
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Beal J, Farny NG, Haddock-Angelli T, Selvarajah V, Baldwin GS, Buckley-Taylor R, Gershater M, Kiga D, Marken J, Sanchania V, Sison A, Workman CT. Robust estimation of bacterial cell count from optical density. Commun Biol 2020; 3:512. [PMID: 32943734 PMCID: PMC7499192 DOI: 10.1038/s42003-020-01127-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 07/03/2020] [Indexed: 11/17/2022] Open
Abstract
Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data. In an inter-laboratory study, the authors compare the accuracy and performance of three optical density calibration protocols (colloidal silica, serial dilution of silica microspheres, and colony-forming unit (CFU) assay). They demonstrate that serial dilution of silica microspheres is the best of these tested protocols, allowing precise and robust calibration that is easily assessed for quality control and can also evaluate the effective linear range of an instrument.
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Affiliation(s)
- Jacob Beal
- Raytheon BBN Technologies, Cambridge, MA, USA.
| | - Natalie G Farny
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, USA.
| | | | | | - Geoff S Baldwin
- Department of Life Sciences and IC-Centre for Synthetic Biology, Imperial College London, London, UK.
| | - Russell Buckley-Taylor
- Department of Life Sciences and IC-Centre for Synthetic Biology, Imperial College London, London, UK
| | | | - Daisuke Kiga
- Faculty of Science and Engineering, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - John Marken
- Department of Bioengineering, California Institute of Technology, Pasadena, CA, USA
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39
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Kelwick RJR, Webb AJ, Freemont PS. Biological Materials: The Next Frontier for Cell-Free Synthetic Biology. Front Bioeng Biotechnol 2020; 8:399. [PMID: 32478045 PMCID: PMC7235315 DOI: 10.3389/fbioe.2020.00399] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 04/08/2020] [Indexed: 12/13/2022] Open
Abstract
Advancements in cell-free synthetic biology are enabling innovations in sustainable biomanufacturing, that may ultimately shift the global manufacturing paradigm toward localized and ecologically harmonized production processes. Cell-free synthetic biology strategies have been developed for the bioproduction of fine chemicals, biofuels and biological materials. Cell-free workflows typically utilize combinations of purified enzymes, cell extracts for biotransformation or cell-free protein synthesis reactions, to assemble and characterize biosynthetic pathways. Importantly, cell-free reactions can combine the advantages of chemical engineering with metabolic engineering, through the direct addition of co-factors, substrates and chemicals -including those that are cytotoxic. Cell-free synthetic biology is also amenable to automatable design cycles through which an array of biological materials and their underpinning biosynthetic pathways can be tested and optimized in parallel. Whilst challenges still remain, recent convergences between the materials sciences and these advancements in cell-free synthetic biology enable new frontiers for materials research.
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Affiliation(s)
- Richard J. R. Kelwick
- Section of Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Alexander J. Webb
- Section of Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Paul S. Freemont
- Section of Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
- The London Biofoundry, Imperial College Translation & Innovation Hub, London, United Kingdom
- UK Dementia Research Institute Care Research and Technology Centre, Imperial College London, London, United Kingdom
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40
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Bartley BA, Beal J, Karr JR, Strychalski EA. Organizing genome engineering for the gigabase scale. Nat Commun 2020; 11:689. [PMID: 32019919 PMCID: PMC7000699 DOI: 10.1038/s41467-020-14314-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 12/18/2019] [Indexed: 12/11/2022] Open
Abstract
Genome-scale engineering holds great potential to impact science, industry, medicine, and society, and recent improvements in DNA synthesis have enabled the manipulation of megabase genomes. However, coordinating and integrating the workflows and large teams necessary for gigabase genome engineering remains a considerable challenge. We examine this issue and recommend a path forward by: 1) adopting and extending existing representations for designs, assembly plans, samples, data, and workflows; 2) developing new technologies for data curation and quality control; 3) conducting fundamental research on genome-scale modeling and design; and 4) developing new legal and contractual infrastructure to facilitate collaboration.
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Affiliation(s)
| | - Jacob Beal
- Raytheon BBN Technologies, Cambridge, MA, 02138, USA.
| | - Jonathan R Karr
- Icahn Institute and Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10128, USA
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41
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Neves D, Vos S, Blank LM, Ebert BE. Pseudomonas mRNA 2.0: Boosting Gene Expression Through Enhanced mRNA Stability and Translational Efficiency. Front Bioeng Biotechnol 2020; 7:458. [PMID: 32039175 PMCID: PMC6993053 DOI: 10.3389/fbioe.2019.00458] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 12/19/2019] [Indexed: 11/14/2022] Open
Abstract
High gene expression of enzymes partaking in recombinant production pathways is a desirable trait among cell factories belonging to all different kingdoms of life. High enzyme abundance is generally aimed for by utilizing strong promoters, which ramp up gene transcription and mRNA levels. Increased protein abundance can alternatively be achieved by optimizing the expression on the post-transcriptional level. Here, we evaluated protein synthesis with a previously proposed optimized gene expression architecture, in which mRNA stability and translation initiation are modulated by genetic parts such as self-cleaving ribozymes and a bicistronic design, which have initially been described to support the standardization of gene expression. The optimized gene expression architecture was tested in Pseudomonas taiwanensis VLB120, a promising, novel microbial cell factory. The expression cassette was employed on a plasmid basis and after single genomic integration. We used three constitutive and two inducible promoters to drive the expression of two fluorescent reporter proteins and a short acetoin biosynthesis pathway. The performance was confronted with that of a traditional expression cassette harboring the same promoter and gene of interest but lacking the genetic parts for increased expression efficiency. The optimized expression cassette granted higher protein abundance independently of the expression basis or promoter used proving its value for applications requiring high protein abundance.
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Affiliation(s)
- Dário Neves
- Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany
| | - Stefan Vos
- Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany
| | - Lars M Blank
- Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany
| | - Birgitta E Ebert
- Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany.,Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia.,CSIRO Synthetic Biology Future Science Platform, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Brisbane, QLD, Australia
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42
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Kent R, Dixon N. Contemporary Tools for Regulating Gene Expression in Bacteria. Trends Biotechnol 2019; 38:316-333. [PMID: 31679824 DOI: 10.1016/j.tibtech.2019.09.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/16/2019] [Accepted: 09/17/2019] [Indexed: 12/14/2022]
Abstract
Insights from novel mechanistic paradigms in gene expression control have led to the development of new gene expression systems for bioproduction, control, and sensing applications. Coupled with a greater understanding of synthetic burden and modern creative biodesign approaches, contemporary bacterial gene expression tools and systems are emerging that permit fine-tuning of expression, enabling greater predictability and maximisation of specific productivity, while minimising deleterious effects upon cell viability. These advances have been achieved by using a plethora of regulatory tools, operating at all levels of the so-called 'central dogma' of molecular biology. In this review, we discuss these gene regulation tools in the context of their design, prototyping, integration into expression systems, and biotechnological application.
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Affiliation(s)
- Ross Kent
- Manchester Institute of Biotechnology and School of Chemistry, University of Manchester, Manchester, UK
| | - Neil Dixon
- Manchester Institute of Biotechnology and School of Chemistry, University of Manchester, Manchester, UK.
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43
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Boada Y, Vignoni A, Alarcon-Ruiz I, Andreu-Vilarroig C, Monfort-Llorens R, Requena A, Picó J. Characterization of Gene Circuit Parts Based on Multiobjective Optimization by Using Standard Calibrated Measurements. Chembiochem 2019; 20:2653-2665. [PMID: 31269324 DOI: 10.1002/cbic.201900272] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 06/12/2019] [Indexed: 01/08/2023]
Abstract
Standardization and characterization of biological parts is necessary for the further development of bottom-up synthetic biology. Herein, an easy-to-use methodology that embodies both a calibration procedure and a multiobjective optimization approach is proposed to characterize biological parts. The calibration procedure generates values for specific fluorescence per cell expressed as standard units of molecules of equivalent fluorescein per particle. The use of absolute standard units enhances the characterization of model parameters for biological parts by bringing measurements and estimations results from different sources into a common domain, so they can be integrated and compared faithfully. The multiobjective optimization procedure exploits these concepts by estimating the values of the model parameters, which represent biological parts of interest, while considering a varied range of experimental and circuit contexts. Thus, multiobjective optimization provides a robust characterization of them. The proposed calibration and characterization methodology can be used as a guide for good practices in dry and wet laboratories; thus allowing not only portability between models, but is also useful for generating libraries of tested and well-characterized biological parts.
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Affiliation(s)
- Yadira Boada
- Synthetic Biology and Biosystems Control Lab, I.U. de Automática e Informática Industrial (ai2), Universitat Politècnica de Valencia, Camino de Vera S/N, 46022, Valencia, Spain.,Centro Universitario EDEM, Escuela de Empresarios, La Marina de València, Muelle de la Aduana S/N, 46024, Valencia, Spain
| | - Alejandro Vignoni
- Synthetic Biology and Biosystems Control Lab, I.U. de Automática e Informática Industrial (ai2), Universitat Politècnica de Valencia, Camino de Vera S/N, 46022, Valencia, Spain
| | - Iván Alarcon-Ruiz
- Synthetic Biology and Biosystems Control Lab, I.U. de Automática e Informática Industrial (ai2), Universitat Politècnica de Valencia, Camino de Vera S/N, 46022, Valencia, Spain.,Escuela Tècnica Superior de Ingeniería Agronómica y del Medio Natural, Universitat Politècnica de Valencia, Camino de Vera S/N, 46022, Valencia, Spain
| | - Carlos Andreu-Vilarroig
- Escuela Técnica Superior de Ingeniería Industrial, Universitat Politècnica de Valencia, Camino de Vera S/N, 46022, Valencia, Spain
| | - Roger Monfort-Llorens
- Synthetic Biology and Biosystems Control Lab, I.U. de Automática e Informática Industrial (ai2), Universitat Politècnica de Valencia, Camino de Vera S/N, 46022, Valencia, Spain.,Escuela Técnica Superior de Ingeniería Industrial, Universitat Politècnica de Valencia, Camino de Vera S/N, 46022, Valencia, Spain
| | - Adrián Requena
- Synthetic Biology and Biosystems Control Lab, I.U. de Automática e Informática Industrial (ai2), Universitat Politècnica de Valencia, Camino de Vera S/N, 46022, Valencia, Spain.,Escuela Tècnica Superior de Ingeniería Agronómica y del Medio Natural, Universitat Politècnica de Valencia, Camino de Vera S/N, 46022, Valencia, Spain
| | - Jesús Picó
- Synthetic Biology and Biosystems Control Lab, I.U. de Automática e Informática Industrial (ai2), Universitat Politècnica de Valencia, Camino de Vera S/N, 46022, Valencia, Spain
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44
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Beal J, Overney C, Adler A, Yaman F, Tiberio L, Samineni M. TASBE Flow Analytics: A Package for Calibrated Flow Cytometry Analysis. ACS Synth Biol 2019; 8:1524-1529. [PMID: 31053031 DOI: 10.1021/acssynbio.8b00533] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Flow cytometry is a powerful method for high-throughput precision measurement of cell fluorescence and size. Effective use of this tool for quantification of synthetic biology devices and circuits, however, generally requires careful application of complex multistage workflows for calibration, filtering, and analysis with appropriate statistics. The TASBE Flow Analytics package provides a free, open, and accessible implementation of such workflows in a form designed for high-throughput analysis of large synthetic biology data sets. Given a set of experimental samples and controls, this package can process them to output calibrated data, quantitative analyses and comparisons, automatically generated figures, and detailed debugging and diagnostic reports in both human-readable and machine-readable forms. TASBE Flow Analytics can be used through a simple user-friendly interactive Excel interface, as a library supporting Matlab, Octave, or Python interactive sessions, or as a component integrated into automated workflows.
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Affiliation(s)
- Jacob Beal
- Raytheon BBN Technologies, Cambridge, Massachusetts 02138, United States
| | - Cassandra Overney
- Raytheon BBN Technologies, Cambridge, Massachusetts 02138, United States
- Olin College, Needham, Massachusetts 02492, United States
| | - Aaron Adler
- Raytheon BBN Technologies, Cambridge, Massachusetts 02138, United States
| | - Fusun Yaman
- Raytheon BBN Technologies, Cambridge, Massachusetts 02138, United States
| | - Lisa Tiberio
- Raytheon BBN Technologies, Cambridge, Massachusetts 02138, United States
| | - Meher Samineni
- Raytheon BBN Technologies, Cambridge, Massachusetts 02138, United States
- University of Utah, Salt Lake City, Utah 84112, United States
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45
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Rapid and cost-effective evaluation of bacterial viability using fluorescence spectroscopy. Anal Bioanal Chem 2019; 411:3653-3663. [PMID: 31049617 PMCID: PMC6571086 DOI: 10.1007/s00216-019-01848-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/03/2019] [Accepted: 04/12/2019] [Indexed: 01/25/2023]
Abstract
A rapid and easy method that takes advantage of an inexpensive and portable fibre-based spectroscopic system (optrode) to determine the ratio of live to dead bacteria is proposed. Mixtures of live and dead Escherichia coli with proportions of live:dead cells varying from 0 to 100% were stained using SYTO 9 and propidium iodide (PI) and measured using the optrode. We demonstrated several approaches to obtaining the proportions of live:dead E. coli in a mixture of both live and dead, from analyses of the fluorescence spectra collected by the optrode. To find a suitable technique for predicting the percentage of live bacteria in a sample, four analysis methods were assessed and compared: SYTO 9:PI fluorescence intensity ratio, an adjusted fluorescence intensity ratio, single-spectrum support vector regression (SVR) and multi-spectra SVR. Of the four analysis methods, multi-spectra SVR obtained the most reliable results and was able to predict the percentage of live bacteria in 108 bacteria/mL samples between c. 7 and 100% live, and in 107 bacteria/mL samples between c. 7 and 73% live. By demonstrating the use of multi-spectra SVR and the optrode to monitor E. coli viability, we raise points of consideration for spectroscopic analysis of SYTO 9 and PI and aim to lay the foundation for future work that uses similar methods for different bacterial species.
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46
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Ou F, McGoverin C, Swift S, Vanholsbeeck F. Near real-time enumeration of live and dead bacteria using a fibre-based spectroscopic device. Sci Rep 2019; 9:4807. [PMID: 30886183 PMCID: PMC6423134 DOI: 10.1038/s41598-019-41221-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/28/2019] [Indexed: 01/05/2023] Open
Abstract
A rapid, cost-effective and easy method that allows on-site determination of the concentration of live and dead bacterial cells using a fibre-based spectroscopic device (the optrode system) is proposed and demonstrated. Identification of live and dead bacteria was achieved by using the commercially available dyes SYTO 9 and propidium iodide, and fluorescence spectra were measured by the optrode. Three spectral processing methods were evaluated for their effectiveness in predicting the original bacterial concentration in the samples: principal components regression (PCR), partial least squares regression (PLSR) and support vector regression (SVR). Without any sample pre-concentration, PCR achieved the most reliable results. It was able to quantify live bacteria from 108 down to 106.2 bacteria/mL and showed the potential to detect as low as 105.7 bacteria/mL. Meanwhile, enumeration of dead bacteria using PCR was achieved between 108 and 107 bacteria/mL. The general procedures described in this article can be applied or modified for the enumeration of bacteria within populations stained with fluorescent dyes. The optrode is a promising device for the enumeration of live and dead bacterial populations particularly where rapid, on-site measurement and analysis is required.
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Affiliation(s)
- Fang Ou
- Department of Physics, The University of Auckland, Auckland, New Zealand.
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Auckland, New Zealand.
| | - Cushla McGoverin
- Department of Physics, The University of Auckland, Auckland, New Zealand
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Auckland, New Zealand
| | - Simon Swift
- School of Medical Sciences, The University of Auckland, Auckland, New Zealand
| | - Frédérique Vanholsbeeck
- Department of Physics, The University of Auckland, Auckland, New Zealand
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Auckland, New Zealand
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47
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Component Characterization in a Growth-Dependent Physiological Context: Optimal Experimental Design. Processes (Basel) 2019. [DOI: 10.3390/pr7010052] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Synthetic biology design challenges have driven the use of mathematical models to characterize genetic components and to explore complex design spaces. Traditional approaches to characterization have largely ignored the effect of strain and growth conditions on the dynamics of synthetic genetic circuits, and have thus confounded intrinsic features of the circuit components with cell-level context effects. We present a model that distinguishes an activated gene’s intrinsic kinetics from its physiological context. We then demonstrate an optimal experimental design approach to identify dynamic induction experiments for efficient estimation of the component’s intrinsic parameters. Maximally informative experiments are chosen by formulating the design as an optimal control problem; direct multiple-shooting is used to identify the optimum. Our numerical results suggest that the intrinsic parameters of a genetic component can be more accurately estimated using optimal experimental designs, and that the choice of growth rates, sampling schedule, and input profile each play an important role. The proposed approach to coupled component–host modelling can support gene circuit design across a range of physiological conditions.
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48
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Vignoni A, Boada Y, Boada Acosta L, Andreu-Vilarroig C, Alarcón I, Requena A, Picó J. Fluorescence calibration and color equivalence for quantitative synthetic biology. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.ifacol.2019.12.247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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49
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Boeing P, Leon M, Nesbeth DN, Finkelstein A, Barnes CP. Towards an Aspect-Oriented Design and Modelling Framework for Synthetic Biology. Processes (Basel) 2018; 6:167. [PMID: 30568914 PMCID: PMC6296438 DOI: 10.3390/pr6090167] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Work on synthetic biology has largely used a component-based metaphor for system construction. While this paradigm has been successful for the construction of numerous systems, the incorporation of contextual design issues-either compositional, host or environmental-will be key to realising more complex applications. Here, we present a design framework that radically steps away from a purely parts-based paradigm by using aspect-oriented software engineering concepts. We believe that the notion of concerns is a powerful and biologically credible way of thinking about system synthesis. By adopting this approach, we can separate core concerns, which represent modular aims of the design, from cross-cutting concerns, which represent system-wide attributes. The explicit handling of cross-cutting concerns allows for contextual information to enter the design process in a modular way. As a proof-of-principle, we implemented the aspect-oriented approach in the Python tool, SynBioWeaver, which enables the combination, or weaving, of core and cross-cutting concerns. The power and flexibility of this framework is demonstrated through a number of examples covering the inclusion of part context, combining circuit designs in a context dependent manner, and the generation of rule, logic and reaction models from synthetic circuit designs.
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Affiliation(s)
- Philipp Boeing
- Department of Computer Science, UCL, London WC1E 6BT, UK
| | - Miriam Leon
- Department of Cell and Developmental Biology, UCL, London WC1E 6BT, UK
| | | | | | - Chris P. Barnes
- Department of Cell and Developmental Biology, UCL, London WC1E 6BT, UK
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