1
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Mahdizade Ari M, Dadgar L, Elahi Z, Ghanavati R, Taheri B. Genetically Engineered Microorganisms and Their Impact on Human Health. Int J Clin Pract 2024; 2024:6638269. [PMID: 38495751 PMCID: PMC10944348 DOI: 10.1155/2024/6638269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 11/20/2023] [Accepted: 02/12/2024] [Indexed: 03/19/2024] Open
Abstract
The emergence of antibiotic-resistant strains, the decreased effectiveness of conventional therapies, and the side effects have led researchers to seek a safer, more cost-effective, patient-friendly, and effective method that does not develop antibiotic resistance. With progress in synthetic biology and genetic engineering, genetically engineered microorganisms effective in treatment, prophylaxis, drug delivery, and diagnosis have been developed. The present study reviews the types of genetically engineered bacteria and phages, their impacts on diseases, cancer, and metabolic and inflammatory disorders, the biosynthesis of these modified strains, the route of administration, and their effects on the environment. We conclude that genetically engineered microorganisms can be considered promising candidates for adjunctive treatment of diseases and cancers.
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Affiliation(s)
- Marzie Mahdizade Ari
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
- Microbial Biotechnology Research Centre, Iran University of Medical Sciences, Tehran, Iran
| | - Leila Dadgar
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
- Microbial Biotechnology Research Centre, Iran University of Medical Sciences, Tehran, Iran
| | - Zahra Elahi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
- Microbial Biotechnology Research Centre, Iran University of Medical Sciences, Tehran, Iran
| | | | - Behrouz Taheri
- Department of Biotechnology, School of Medicine, Ahvaz Jundishapour University of medical Sciences, Ahvaz, Iran
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2
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Hayashi N, Lai Y, Fuerte-Stone J, Mimee M, Lu TK. Cas9-assisted biological containment of a genetically engineered human commensal bacterium and genetic elements. Nat Commun 2024; 15:2096. [PMID: 38453913 PMCID: PMC10920895 DOI: 10.1038/s41467-024-45893-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 02/07/2024] [Indexed: 03/09/2024] Open
Abstract
Sophisticated gene circuits built by synthetic biology can enable bacteria to sense their environment and respond predictably. Engineered biosensing bacteria outfitted with such circuits can potentially probe the human gut microbiome to prevent, diagnose, or treat disease. To provide robust biocontainment for engineered bacteria, we devised a Cas9-assisted auxotrophic biocontainment system combining thymidine auxotrophy, an Engineered Riboregulator (ER) for controlled gene expression, and a CRISPR Device (CD). The CD prevents the engineered bacteria from acquiring thyA via horizontal gene transfer, which would disrupt the biocontainment system, and inhibits the spread of genetic elements by killing bacteria harboring the gene cassette. This system tunably controlled gene expression in the human gut commensal bacterium Bacteroides thetaiotaomicron, prevented escape from thymidine auxotrophy, and blocked transgene dissemination. These capabilities were validated in vitro and in vivo. This biocontainment system exemplifies a powerful strategy for bringing genetically engineered microorganisms safely into biomedicine.
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Affiliation(s)
- Naoki Hayashi
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- JSR-Keio University Medical and Chemical Innovation Center (JKiC), JSR Corp., 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Yong Lai
- Synthetic Biology Group, MIT Synthetic Biology Center, Massachusetts Institute of Technology (MIT), Cambridge, MA, 02139, USA
- Research Laboratory of Electronics, MIT, Cambridge, MA, 02139, USA
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR
| | - Jay Fuerte-Stone
- Department of Microbiology, The University of Chicago, Chicago, IL, 60637, USA
| | - Mark Mimee
- Department of Microbiology, The University of Chicago, Chicago, IL, 60637, USA.
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA.
| | - Timothy K Lu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
- Synthetic Biology Group, MIT Synthetic Biology Center, Massachusetts Institute of Technology (MIT), Cambridge, MA, 02139, USA.
- Research Laboratory of Electronics, MIT, Cambridge, MA, 02139, USA.
- Broad Institute, Cambridge, MA, 02139, USA.
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, 02139, USA.
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3
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Stone A, Youssef A, Rijal S, Zhang R, Tian XJ. Context-dependent redesign of robust synthetic gene circuits. Trends Biotechnol 2024:S0167-7799(24)00003-9. [PMID: 38320912 DOI: 10.1016/j.tibtech.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 02/08/2024]
Abstract
Cells provide dynamic platforms for executing exogenous genetic programs in synthetic biology, resulting in highly context-dependent circuit performance. Recent years have seen an increasing interest in understanding the intricacies of circuit-host relationships, their influence on the synthetic bioengineering workflow, and in devising strategies to alleviate undesired effects. We provide an overview of how emerging circuit-host interactions, such as growth feedback and resource competition, impact both deterministic and stochastic circuit behaviors. We also emphasize control strategies for mitigating these unwanted effects. This review summarizes the latest advances and the current state of host-aware and resource-aware design of synthetic gene circuits.
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Affiliation(s)
- Austin Stone
- School of Biological and Health System Engineering, Arizona State University, Tempe, AZ 85281, USA
| | - Abdelrahaman Youssef
- School of Biological and Health System Engineering, Arizona State University, Tempe, AZ 85281, USA
| | - Sadikshya Rijal
- School of Biological and Health System Engineering, Arizona State University, Tempe, AZ 85281, USA
| | - Rong Zhang
- School of Biological and Health System Engineering, Arizona State University, Tempe, AZ 85281, USA
| | - Xiao-Jun Tian
- School of Biological and Health System Engineering, Arizona State University, Tempe, AZ 85281, USA.
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4
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George DR, Danciu M, Davenport PW, Lakin MR, Chappell J, Frow EK. A bumpy road ahead for genetic biocontainment. Nat Commun 2024; 15:650. [PMID: 38245521 PMCID: PMC10799865 DOI: 10.1038/s41467-023-44531-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Accepted: 12/18/2023] [Indexed: 01/22/2024] Open
Affiliation(s)
- Dalton R George
- School for the Future of Innovation in Society, Arizona State University, Tempe, AZ, 85287, USA
- School of Biological & Health Systems Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Mark Danciu
- School of Life Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Peter W Davenport
- Department of Computer Science, University of New Mexico, Albuquerque, NM, 87131, USA
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Matthew R Lakin
- Department of Computer Science, University of New Mexico, Albuquerque, NM, 87131, USA
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, NM, 87131, USA
- Department of Chemical & Biological Engineering, University of New Mexico, Albuquerque, NM, 87131, USA
| | - James Chappell
- Department of Biosciences & Department of Bioengineering, Rice University, Houston, TX, 77005, USA
| | - Emma K Frow
- School for the Future of Innovation in Society, Arizona State University, Tempe, AZ, 85287, USA.
- School of Biological & Health Systems Engineering, Arizona State University, Tempe, AZ, 85287, USA.
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5
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Chang T, Ding W, Yan S, Wang Y, Zhang H, Zhang Y, Ping Z, Zhang H, Huang Y, Zhang J, Wang D, Zhang W, Xu X, Shen Y, Fu X. A robust yeast biocontainment system with two-layered regulation switch dependent on unnatural amino acid. Nat Commun 2023; 14:6487. [PMID: 37838746 PMCID: PMC10576815 DOI: 10.1038/s41467-023-42358-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 10/09/2023] [Indexed: 10/16/2023] Open
Abstract
Synthetic auxotrophy in which cell viability depends on the presence of an unnatural amino acid (unAA) provides a powerful strategy to restrict unwanted propagation of genetically modified organisms (GMOs) in open environments and potentially prevent industrial espionage. Here, we describe a generic approach for robust biocontainment of budding yeast dependent on unAA. By understanding escape mechanisms, we specifically optimize our strategies by introducing designed "immunity" to the generation of amber-suppressor tRNAs and developing the transcriptional- and translational-based biocontainment switch. We further develop a fitness-oriented screening method to easily obtain multiplex safeguard strains that exhibit robust growth and undetectable escape frequency (<~10-9) on solid media for 14 days. Finally, we show that employing our multiplex safeguard system could restrict the proliferation of strains of interest in a real fermentation scenario, highlighting the great potential of our yeast biocontainment strategy to protect the industrial proprietary strains.
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Affiliation(s)
- Tiantian Chang
- College of Life Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
- BGI Research, Shenzhen, 518083, China
| | - Weichao Ding
- College of Life Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
- BGI Research, Shenzhen, 518083, China
- BGI Research, Changzhou, 213299, China
- Guangdong Provincial Key Laboratory of Genome Read and Write, BGI Research, Shenzhen, 518083, China
| | - Shirui Yan
- BGI Research, Shenzhen, 518083, China
- BGI Research, Changzhou, 213299, China
- Guangdong Provincial Key Laboratory of Genome Read and Write, BGI Research, Shenzhen, 518083, China
| | - Yun Wang
- BGI Research, Shenzhen, 518083, China
- BGI Research, Changzhou, 213299, China
- Guangdong Provincial Key Laboratory of Genome Read and Write, BGI Research, Shenzhen, 518083, China
| | - Haoling Zhang
- BGI Research, Shenzhen, 518083, China
- BGI Research, Changzhou, 213299, China
- Guangdong Provincial Key Laboratory of Genome Read and Write, BGI Research, Shenzhen, 518083, China
| | - Yu Zhang
- BGI Research, Shenzhen, 518083, China
- Guangdong Provincial Key Laboratory of Genome Read and Write, BGI Research, Shenzhen, 518083, China
| | - Zhi Ping
- BGI Research, Shenzhen, 518083, China
- BGI Research, Changzhou, 213299, China
- Guangdong Provincial Key Laboratory of Genome Read and Write, BGI Research, Shenzhen, 518083, China
| | - Huiming Zhang
- College of Life Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
- BGI Research, Shenzhen, 518083, China
| | - Yijian Huang
- College of Life Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
- BGI Research, Shenzhen, 518083, China
| | - Jiahui Zhang
- College of Life Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
- BGI Research, Shenzhen, 518083, China
| | - Dan Wang
- Guangdong Provincial Key Laboratory of Interdisciplinary Research and Application for Data Science, BNU-HKBU United International College, Zhuhai, 519087, China
- BNU-HKBU United International College, Zhuhai, 519087, China
| | - Wenwei Zhang
- BGI Research, Shenzhen, 518083, China
- Guangdong Provincial Key Laboratory of Genome Read and Write, BGI Research, Shenzhen, 518083, China
| | - Xun Xu
- BGI Research, Shenzhen, 518083, China
- BGI Research, Changzhou, 213299, China
- Guangdong Provincial Key Laboratory of Genome Read and Write, BGI Research, Shenzhen, 518083, China
| | - Yue Shen
- College of Life Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China.
- BGI Research, Shenzhen, 518083, China.
- BGI Research, Changzhou, 213299, China.
- Guangdong Provincial Key Laboratory of Genome Read and Write, BGI Research, Shenzhen, 518083, China.
| | - Xian Fu
- BGI Research, Shenzhen, 518083, China.
- BGI Research, Changzhou, 213299, China.
- Guangdong Provincial Key Laboratory of Genome Read and Write, BGI Research, Shenzhen, 518083, China.
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6
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Chlebek JL, Leonard SP, Kang-Yun C, Yung MC, Ricci DP, Jiao Y, Park DM. Prolonging genetic circuit stability through adaptive evolution of overlapping genes. Nucleic Acids Res 2023; 51:7094-7108. [PMID: 37260076 PMCID: PMC10359631 DOI: 10.1093/nar/gkad484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/12/2023] [Accepted: 05/23/2023] [Indexed: 06/02/2023] Open
Abstract
The development of synthetic biological circuits that maintain functionality over application-relevant time scales remains a significant challenge. Here, we employed synthetic overlapping sequences in which one gene is encoded or 'entangled' entirely within an alternative reading frame of another gene. In this design, the toxin-encoding relE was entangled within ilvA, which encodes threonine deaminase, an enzyme essential for isoleucine biosynthesis. A functional entanglement construct was obtained upon modification of the ribosome-binding site of the internal relE gene. Using this optimized design, we found that the selection pressure to maintain functional IlvA stabilized the production of burdensome RelE for >130 generations, which compares favorably with the most stable kill-switch circuits developed to date. This stabilizing effect was achieved through a complete alteration of the allowable landscape of mutations such that mutations inactivating the entangled genes were disfavored. Instead, the majority of lineages accumulated mutations within the regulatory region of ilvA. By reducing baseline relE expression, these more 'benign' mutations lowered circuit burden, which suppressed the accumulation of relE-inactivating mutations, thereby prolonging kill-switch function. Overall, this work demonstrates the utility of sequence entanglement paired with an adaptive laboratory evolution campaign to increase the evolutionary stability of burdensome synthetic circuits.
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Affiliation(s)
- Jennifer L Chlebek
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Sean P Leonard
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Christina Kang-Yun
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Mimi C Yung
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Dante P Ricci
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Yongqin Jiao
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Dan M Park
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
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7
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Hedin KA, Kruse V, Vazquez-Uribe R, Sommer MOA. Biocontainment strategies for in vivo applications of Saccharomyces boulardii. Front Bioeng Biotechnol 2023; 11:1136095. [PMID: 36890914 PMCID: PMC9986445 DOI: 10.3389/fbioe.2023.1136095] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 02/06/2023] [Indexed: 02/22/2023] Open
Abstract
The human gastrointestinal tract is a complex and dynamic environment, playing a crucial role in human health. Microorganisms engineered to express a therapeutic activity have emerged as a novel modality to manage numerous diseases. Such advanced microbiome therapeutics (AMTs) must be contained within the treated individual. Hence safe and robust biocontainment strategies are required to prevent the proliferation of microbes outside the treated individual. Here we present the first biocontainment strategy for a probiotic yeast, demonstrating a multi-layered strategy combining an auxotrophic and environmental-sensitive strategy. We knocked out the genes THI6 and BTS1, causing thiamine auxotrophy and increased sensitivity to cold, respectively. The biocontained Saccharomyces boulardii showed restricted growth in the absence of thiamine above 1 ng/ml and exhibited a severe growth defect at temperatures below 20°C. The biocontained strain was well tolerated and viable in mice and demonstrated equal efficiency in peptide production as the ancestral non-biocontained strain. In combination, the data support that thi6∆ and bts1∆ enable biocontainment of S. boulardii, which could be a relevant chassis for future yeast-based AMTs.
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Affiliation(s)
- Karl Alex Hedin
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, Denmark
| | - Vibeke Kruse
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, Denmark
| | - Ruben Vazquez-Uribe
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, Denmark
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8
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Thai TD, Lim W, Na D. Synthetic bacteria for the detection and bioremediation of heavy metals. Front Bioeng Biotechnol 2023; 11:1178680. [PMID: 37122866 PMCID: PMC10133563 DOI: 10.3389/fbioe.2023.1178680] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 04/04/2023] [Indexed: 05/02/2023] Open
Abstract
Toxic heavy metal accumulation is one of anthropogenic environmental pollutions, which poses risks to human health and ecological systems. Conventional heavy metal remediation approaches rely on expensive chemical and physical processes leading to the formation and release of other toxic waste products. Instead, microbial bioremediation has gained interest as a promising and cost-effective alternative to conventional methods, but the genetic complexity of microorganisms and the lack of appropriate genetic engineering technologies have impeded the development of bioremediating microorganisms. Recently, the emerging synthetic biology opened a new avenue for microbial bioremediation research and development by addressing the challenges and providing novel tools for constructing bacteria with enhanced capabilities: rapid detection and degradation of heavy metals while enhanced tolerance to toxic heavy metals. Moreover, synthetic biology also offers new technologies to meet biosafety regulations since genetically modified microorganisms may disrupt natural ecosystems. In this review, we introduce the use of microorganisms developed based on synthetic biology technologies for the detection and detoxification of heavy metals. Additionally, this review explores the technical strategies developed to overcome the biosafety requirements associated with the use of genetically modified microorganisms.
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9
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Hu H, Wang M, Huang Y, Xu Z, Xu P, Nie Y, Tang H. Guided by the principles of microbiome engineering: Accomplishments and perspectives for environmental use. MLIFE 2022; 1:382-398. [PMID: 38818482 PMCID: PMC10989833 DOI: 10.1002/mlf2.12043] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/19/2022] [Accepted: 09/02/2022] [Indexed: 06/01/2024]
Abstract
Although the accomplishments of microbiome engineering highlight its significance for the targeted manipulation of microbial communities, knowledge and technical gaps still limit the applications of microbiome engineering in biotechnology, especially for environmental use. Addressing the environmental challenges of refractory pollutants and fluctuating environmental conditions requires an adequate understanding of the theoretical achievements and practical applications of microbiome engineering. Here, we review recent cutting-edge studies on microbiome engineering strategies and their classical applications in bioremediation. Moreover, a framework is summarized for combining both top-down and bottom-up approaches in microbiome engineering toward improved applications. A strategy to engineer microbiomes for environmental use, which avoids the build-up of toxic intermediates that pose a risk to human health, is suggested. We anticipate that the highlighted framework and strategy will be beneficial for engineering microbiomes to address difficult environmental challenges such as degrading multiple refractory pollutants and sustain the performance of engineered microbiomes in situ with indigenous microorganisms under fluctuating conditions.
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Affiliation(s)
- Haiyang Hu
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
| | - Miaoxiao Wang
- Department of Environmental Systems ScienceETH ZürichZürichSwitzerland
- Department of Environmental MicrobiologyETH ZürichEawagSwitzerland
| | - Yiqun Huang
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
| | - Zhaoyong Xu
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
| | - Ping Xu
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
| | - Yong Nie
- College of EngineeringPeking UniversityBeijingChina
| | - Hongzhi Tang
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
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10
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Sridhar S, Ajo-Franklin CM, Masiello CA. A Framework for the Systematic Selection of Biosensor Chassis for Environmental Synthetic Biology. ACS Synth Biol 2022; 11:2909-2916. [PMID: 35961652 PMCID: PMC9486965 DOI: 10.1021/acssynbio.2c00079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Microbial biosensors sense and report exposures to stimuli, thereby facilitating our understanding of environmental processes. Successful design and deployment of biosensors hinge on the persistence of the microbial host of the genetic circuit, termed the chassis. However, model chassis organisms may persist poorly in environmental conditions. In contrast, non-model organisms persist better in environmental conditions but are limited by other challenges, such as genetic intractability and part unavailability. Here we identify ecological, metabolic, and genetic constraints for chassis development and propose a conceptual framework for the systematic selection of environmental biosensor chassis. We identify key challenges with using current model chassis and delineate major points of conflict in choosing the most suitable organisms as chassis for environmental biosensing. This framework provides a way forward in the selection of biosensor chassis for environmental synthetic biology.
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Affiliation(s)
- Swetha Sridhar
- Systems,
Synthetic, and Physical Biology Graduate Program, Rice University, 6100 Main Street, MS-180, Houston, Texas 77005, United
States,Tel: 713-348-2565.
| | - Caroline M. Ajo-Franklin
- Department
of BioSciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States
| | - Caroline A. Masiello
- Department
of BioSciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States,Department
of Earth, Environmental, and Planetary Sciences, Rice University, 6100 Main St, MS-126, Houston, Texas 77005, United
States
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11
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De Wannemaeker L, Bervoets I, De Mey M. Unlocking the bacterial domain for industrial biotechnology applications using universal parts and tools. Biotechnol Adv 2022; 60:108028. [PMID: 36031082 DOI: 10.1016/j.biotechadv.2022.108028] [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: 03/10/2022] [Revised: 07/29/2022] [Accepted: 08/16/2022] [Indexed: 11/02/2022]
Abstract
Synthetic biology can play a major role in the development of sustainable industrial biotechnology processes. However, the development of economically viable production processes is currently hampered by the limited availability of host organisms that can be engineered for a specific production process. To date, standard hosts such as Escherichia coli and Saccharomyces cerevisiae are often used as starting points for process development since parts and tools allowing their engineering are readily available. However, their suboptimal metabolic background or impaired performance at industrial scale for a desired production process, can result in increased costs associated with process development and/or disappointing production titres. Building a universal and portable gene expression system allowing genetic engineering of hosts across the bacterial domain would unlock the bacterial domain for industrial biotechnology applications in a highly standardized manner and doing so, render industrial biotechnology processes more competitive compared to the current polluting chemical processes. This review gives an overview of a selection of bacterial hosts highly interesting for industrial biotechnology based on both their metabolic and process optimization properties. Moreover, the requirements and progress made so far to enable universal, standardized, and portable gene expression across the bacterial domain is discussed.
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Affiliation(s)
- Lien De Wannemaeker
- Centre for Synthetic Biology (CSB), Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Indra Bervoets
- Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Marjan De Mey
- Centre for Synthetic Biology (CSB), Ghent University, Coupure links 653, 9000 Ghent, Belgium.
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12
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Zhu X, Zhaoyang Zhang, Bin Jia, Yuan Y. Current advances of biocontainment strategy in synthetic biology. Chin J Chem Eng 2022. [DOI: 10.1016/j.cjche.2022.07.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Wang L, Peng R, Tian Y, Xu J, Wang B, Han H, Fu X, Gao J, Yao Q. Metabolic engineering of Escherichia coli for efficient degradation of 4-fluorophenol. AMB Express 2022; 12:55. [PMID: 35567640 PMCID: PMC9107566 DOI: 10.1186/s13568-022-01396-9] [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: 12/21/2021] [Accepted: 05/04/2022] [Indexed: 11/10/2022] Open
Abstract
As a kind of refractory organic pollutant, 4-fluorophenol (4-FP) can be degraded by only a few microorganisms with low efficiency because of the great electron-withdrawing ability of fluorine atoms. So it is necessary to artificially construct engineered strain to improve the degradation efficiency and meet the requirements of pollutant degradation. In this study, four genes (fpdA2, fpdB, fpdC, and fpdD) for 4-FP degradation from Arthrobacter sp. strain IF1 were optimized and synthesized and then reconstructed into Escherichia coli by a multi-monocistronic vector to obtain recombinant BL-fpd that could degrade 4-FP efficiently. Under optimized induction conditions (inducing the strain by 2 g/L L-arabinose and 1 mM IPTG at 37 ℃), BL-fpd could completely degrade 2 mM 4-FP, 4-chlorophenol, 4-bromophenol, and 4-nitrophenol into β-ketoadipate, which could be further metabolized by the bacteria. FpdA2 showed the highest activity towards 4-bromophenol. The strain could completely degrade 1 mM 4-FP in industrial wastewater within 3 h. This study provided a promising strain for the degradation of 4-FP and some other 4-substituted phenols. The construction technologies of multi-monocistronic expression vector may also be used to construct other organic pollutants degrading bacteria.
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14
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Xue Y, Qiu T, Sun Z, Liu F, Yu B. Mercury bioremediation by engineered Pseudomonas putida KT2440 with adaptationally optimized biosecurity circuit. Environ Microbiol 2022; 24:3022-3036. [PMID: 35555952 DOI: 10.1111/1462-2920.16038] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/25/2022] [Accepted: 05/04/2022] [Indexed: 01/15/2023]
Abstract
Hazardous materials, such as heavy metals, are the major sources of health risk. Using genetically modified organisms (GMOs) to dispose heavy metals has the advantages of strong environmental compatibility and high efficiency. However, the biosecurity of GMOs used in the environment is a major concern. In this study, a self-controlled genetic circuit was designed and carefully fine-tuned for programmable expression in Pseudomonas putida KT2440, which is a widely used strain for environmental bioremediation. The cell behaviours were controlled by automatically sensing the variation of Hg2+ concentration without any inducer requirement or manual interventions. More than 98% Hg2+ was adsorbed by the engineered strain with a high cell recovery rate of 96% from waterbody. The remaining cells were killed by the suicide module after the mission was accomplished. The escape frequency of the engineered P. putida strain was lower than 10-9 , which meets the recommendation of US NIH guideline for GMOs release (<10-8 ). The same performance was achieved in a model experiment by using natural lake water with addition of Hg2+ . The microbial diversity analysis further confirmed that the remediation process made little impact on the indigenous ecosystem. Thus, this study provides a practical method for environmental remediation by using GMOs.
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Affiliation(s)
- Yubin Xue
- CAS Key Laboratory of Microbial Physiological & Metabolic Engineering, State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Tianlei Qiu
- Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Zhi Sun
- CAS Key Laboratory of Microbial Physiological & Metabolic Engineering, State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Feixia Liu
- CAS Key Laboratory of Microbial Physiological & Metabolic Engineering, State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Bo Yu
- CAS Key Laboratory of Microbial Physiological & Metabolic Engineering, State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
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15
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Pei L, Garfinkel M, Schmidt M. Bottlenecks and opportunities for synthetic biology biosafety standards. Nat Commun 2022; 13:2175. [PMID: 35449163 PMCID: PMC9023567 DOI: 10.1038/s41467-022-29889-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 04/06/2022] [Indexed: 11/09/2022] Open
Affiliation(s)
- Lei Pei
- Biofaction KG, Vienna, Austria
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16
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A genetic toolkit and gene switches to limit Mycoplasma growth for biosafety applications. Nat Commun 2022; 13:1910. [PMID: 35393441 PMCID: PMC8991246 DOI: 10.1038/s41467-022-29574-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 03/24/2022] [Indexed: 12/18/2022] Open
Abstract
Mycoplasmas have exceptionally streamlined genomes and are strongly adapted to their many hosts, which provide them with essential nutrients. Owing to their relative genomic simplicity, Mycoplasmas have been used to develop chassis for biotechnological applications. However, the dearth of robust and precise toolkits for genomic manipulation and tight regulation has hindered any substantial advance. Herein we describe the construction of a robust genetic toolkit for M. pneumoniae, and its successful deployment to engineer synthetic gene switches that control and limit Mycoplasma growth, for biosafety containment applications. We found these synthetic gene circuits to be stable and robust in the long-term, in the context of a minimal cell. With this work, we lay a foundation to develop viable and robust biosafety systems to exploit a synthetic Mycoplasma chassis for live attenuated vectors for therapeutic applications. Mycoplasmas are minimal cell model organisms but lack genetic tools. Here the authors provide a robust genetic toolkit for Mycoplasma demonstrating gene circuit engineering applications.
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17
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Brennan AM. Development of Synthetic Biotics as Treatments for Human Diseases. Synth Biol (Oxf) 2022; 7:ysac001. [PMID: 35350191 PMCID: PMC8944296 DOI: 10.1093/synbio/ysac001] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 12/19/2021] [Accepted: 01/29/2022] [Indexed: 12/02/2022] Open
Abstract
Advances in synthetic biology have allowed the generation of strains of bacteria that are genetically altered to have specific therapeutic benefits. These synthetic biotics, also widely referred to as engineered living therapeutics, have tremendous potential as a new therapeutic modality, and several have advanced into the clinic and human testing. This review outlines some of the unique attributes of synthetic biotics as well as some of the challenges in their development as prescription products. Regulatory considerations are discussed, and a case study of a program that has advanced into Phase 2 testing is provided: SYNB1618 for the treatment of PKU.
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18
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Chee WKD, Yeoh JW, Dao VL, Poh CL. Thermogenetics: Applications come of age. Biotechnol Adv 2022; 55:107907. [PMID: 35041863 DOI: 10.1016/j.biotechadv.2022.107907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 12/13/2021] [Accepted: 01/09/2022] [Indexed: 12/20/2022]
Abstract
Temperature is a ubiquitous physical cue that is non-invasive, penetrative and easy to apply. In the growing field of thermogenetics, through beneficial repurposing of natural thermosensing mechanisms, synthetic biology is bringing new opportunities to design and build robust temperature-sensitive (TS) sensors which forms a thermogenetic toolbox of well characterised biological parts. Recent advancements in technological platforms available have expedited the discovery of novel or de novo thermosensors which are increasingly deployed in many practical temperature-dependent biomedical, industrial and biosafety applications. In all, the review aims to convey both the exhilarating recent technological developments underlying the advancement of thermosensors and the exciting opportunities the nascent thermogenetic field holds for biomedical and biotechnology applications.
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Affiliation(s)
- Wai Kit David Chee
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore; NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore
| | - Jing Wui Yeoh
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore; NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore
| | - Viet Linh Dao
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore; NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore
| | - Chueh Loo Poh
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore; NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), Life Sciences Institute, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore.
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19
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Espeso DR, Dvořák P, Aparicio T, de Lorenzo V. An automated DIY framework for experimental evolution of Pseudomonas putida. Microb Biotechnol 2021; 14:2679-2685. [PMID: 33047876 PMCID: PMC8601172 DOI: 10.1111/1751-7915.13678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 09/12/2020] [Accepted: 09/22/2020] [Indexed: 10/25/2022] Open
Abstract
Adaptive laboratory evolution (ALE) is a general and effective strategy for optimizing the design of engineered genetic circuits and upgrading metabolic phenotypes. However, the specific characteristics of each microorganism typically ask for exclusive conditions that need to be adjusted to the biological chassis at stake. In this work, we have adopted a do-it-yourself (DIY) approach to implement a flexible and automated framework for performing ALE experiments with the environmental bacterium and metabolic engineering platform Pseudomonas putida. The setup includes a dual-chamber semi-continuous log-phase bioreactor design combined with an anti-biofilm layout to manage specific traits of this bacterium in long-term cultivation experiments. As a way of validation, the prototype was instrumental for selecting fast-growing variants of a P. putida strain engineered to metabolize D-xylose as sole carbon and energy source after running an automated 42 days protocol of iterative regrowth. Several genomic changes were identified in the evolved population that pinpointed the role of RNA polymerase in controlling overall physiological conditions during metabolism of the new carbon source.
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Affiliation(s)
- David R. Espeso
- Systems Biology ProgramCentro Nacional de Biotecnología‐CSICCampus de CantoblancoMadrid28049Spain
| | - Pavel Dvořák
- Department of Experimental BiologyFaculty of ScienceMasaryk UniversityBrno62500Czech Republic
| | - Tomás Aparicio
- Systems Biology ProgramCentro Nacional de Biotecnología‐CSICCampus de CantoblancoMadrid28049Spain
| | - Víctor de Lorenzo
- Systems Biology ProgramCentro Nacional de Biotecnología‐CSICCampus de CantoblancoMadrid28049Spain
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20
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Haskett TL, Tkacz A, Poole PS. Engineering rhizobacteria for sustainable agriculture. THE ISME JOURNAL 2021; 15:949-964. [PMID: 33230265 PMCID: PMC8114929 DOI: 10.1038/s41396-020-00835-4] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 10/29/2020] [Accepted: 11/05/2020] [Indexed: 02/06/2023]
Abstract
Exploitation of plant growth promoting (PGP) rhizobacteria (PGPR) as crop inoculants could propel sustainable intensification of agriculture to feed our rapidly growing population. However, field performance of PGPR is typically inconsistent due to suboptimal rhizosphere colonisation and persistence in foreign soils, promiscuous host-specificity, and in some cases, the existence of undesirable genetic regulation that has evolved to repress PGP traits. While the genetics underlying these problems remain largely unresolved, molecular mechanisms of PGP have been elucidated in rigorous detail. Engineering and subsequent transfer of PGP traits into selected efficacious rhizobacterial isolates or entire bacterial rhizosphere communities now offers a powerful strategy to generate improved PGPR that are tailored for agricultural use. Through harnessing of synthetic plant-to-bacteria signalling, attempts are currently underway to establish exclusive coupling of plant-bacteria interactions in the field, which will be crucial to optimise efficacy and establish biocontainment of engineered PGPR. This review explores the many ecological and biotechnical facets of this research.
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Affiliation(s)
- Timothy L. Haskett
- grid.4991.50000 0004 1936 8948Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB UK
| | - Andrzej Tkacz
- grid.4991.50000 0004 1936 8948Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB UK
| | - Philip S. Poole
- grid.4991.50000 0004 1936 8948Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB UK
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21
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Bhatt P, Bhatt K, Sharma A, Zhang W, Mishra S, Chen S. Biotechnological basis of microbial consortia for the removal of pesticides from the environment. Crit Rev Biotechnol 2021; 41:317-338. [PMID: 33730938 DOI: 10.1080/07388551.2020.1853032] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The application of microbial strains as axenic cultures has frequently been employed in a diverse range of sectors. In the natural environment, microbes exist as multispecies and perform better than monocultures. Cell signaling and communication pathways play a key role in engineering microbial consortia, because in a consortium, the microorganisms communicate via diffusible signal molecules. Mixed microbial cultures have gained little attention due to the lack of proper knowledge about their interactions with each other. Some ideas have been proposed to deal with and study various microbes when they live together as a community, for biotechnological application purposes. In natural environments, microbes can possess unique metabolic features. Therefore, microbial consortia divide the metabolic burden among strains in the group and robustly perform pesticide degradation. Synthetic microbial consortia can perform the desired functions at naturally contaminated sites. Therefore, in this article, special attention is paid to the microbial consortia and their function in the natural environment. This review comprehensively discusses the recent applications of microbial consortia in pesticide degradation and environmental bioremediation. Moreover, the future directions of synthetic consortia have been explored. The review also explores the future perspectives and new platforms for these approaches, besides highlighting the practical understanding of the scientific information behind consortia.
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Affiliation(s)
- Pankaj Bhatt
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Kalpana Bhatt
- Department of Botany and Microbiology, Gurukula Kangri University, Haridwar, Uttarakhand, India
| | - Anita Sharma
- Department of Microbiology, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India
| | - Wenping Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Sandhya Mishra
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Shaohua Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
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22
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Deferred control of ammonium cross-feeding in a N 2-fixing bacterium-microalga artificial consortium. Appl Microbiol Biotechnol 2021; 105:2937-2950. [PMID: 33687504 DOI: 10.1007/s00253-021-11210-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 02/22/2021] [Accepted: 02/28/2021] [Indexed: 10/22/2022]
Abstract
There is an increasing interest in the use of N2-fixing bacteria for the sustainable biofertilization of crops. Genetically-optimized bacteria for ammonium release have an improved biofertilization capacity. Some of these strains also cross-feed ammonium into microalgae raising additional concerns on their sustainable use in agriculture due to the potential risk of producing a higher and longer-lasting eutrophication problem than synthetic N-fertilizers. Here we studied the dynamic algal cross-feeding properties of a genetically-modified Azotobacter vinelandii strain which can be tuned to over-accumulate different levels of glutamine synthetase (GS, EC 6.3.1.20) under the control of an exogenous inducer. After switching cells overaccumulating GS into a noninducing medium, they proliferated for several generations at the expense of the previously accumulated GS. Further dilution of GS by cell division slowed-down growth, promoted ammonium-excretion and cross-fed algae. The final bacterial population, and timing and magnitude of algal N-biofertlization was finely tuned in a deferred manner. This tuning was in accordance with the intensity of the previous induction of GS accumulation in the cells. This bacterial population behavior could be maintained up to about 15 bacterial cell generations, until faster-growing and nonammonium excreting cells arose at an apparent high frequency. Further improvements of this genetic engineering strategy might help to align efficiency of N-biofertilizers and safe use in an open environment. KEY POINTS: • Ammonium-excreting bacteria are potential eutrophication agents • GS-dependent deferred control of bacterial growth and ammonium release • Strong but transient ammonium cross-feeding of microalgae.
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23
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Del Valle I, Fulk EM, Kalvapalle P, Silberg JJ, Masiello CA, Stadler LB. Translating New Synthetic Biology Advances for Biosensing Into the Earth and Environmental Sciences. Front Microbiol 2021; 11:618373. [PMID: 33633695 PMCID: PMC7901896 DOI: 10.3389/fmicb.2020.618373] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/17/2020] [Indexed: 12/26/2022] Open
Abstract
The rapid diversification of synthetic biology tools holds promise in making some classically hard-to-solve environmental problems tractable. Here we review longstanding problems in the Earth and environmental sciences that could be addressed using engineered microbes as micron-scale sensors (biosensors). Biosensors can offer new perspectives on open questions, including understanding microbial behaviors in heterogeneous matrices like soils, sediments, and wastewater systems, tracking cryptic element cycling in the Earth system, and establishing the dynamics of microbe-microbe, microbe-plant, and microbe-material interactions. Before these new tools can reach their potential, however, a suite of biological parts and microbial chassis appropriate for environmental conditions must be developed by the synthetic biology community. This includes diversifying sensing modules to obtain information relevant to environmental questions, creating output signals that allow dynamic reporting from hard-to-image environmental materials, and tuning these sensors so that they reliably function long enough to be useful for environmental studies. Finally, ethical questions related to the use of synthetic biosensors in environmental applications are discussed.
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Affiliation(s)
- Ilenne Del Valle
- Systems, Synthetic, and Physical Biology Graduate Program, Rice University, Houston, TX, United States
| | - Emily M. Fulk
- Systems, Synthetic, and Physical Biology Graduate Program, Rice University, Houston, TX, United States
| | - Prashant Kalvapalle
- Systems, Synthetic, and Physical Biology Graduate Program, Rice University, Houston, TX, United States
| | - Jonathan J. Silberg
- Department of BioSciences, Rice University, Houston, TX, United States
- Department of Bioengineering, Rice University, Houston, TX, United States
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, United States
| | - Caroline A. Masiello
- Department of BioSciences, Rice University, Houston, TX, United States
- Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, TX, United States
- Department of Chemistry, Rice University, Houston, TX, United States
| | - Lauren B. Stadler
- Department of Civil and Environmental Engineering, Rice University, Houston, TX, United States
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24
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Kallergi A, Asin‐Garcia E, Martins dos Santos VAP, Landeweerd L. Context matters: On the road to responsible biosafety technologies in synthetic biology. EMBO Rep 2021; 22:e51227. [PMID: 33369847 PMCID: PMC7788449 DOI: 10.15252/embr.202051227] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 07/07/2020] [Indexed: 11/09/2022] Open
Abstract
Biosafety is a major challenge for developing for synthetic organisms. An early focus on application and their context could assist with the design of appropriate genetic safeguards.
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Affiliation(s)
- Amalia Kallergi
- Institute for Science in SocietyRadboud UniversityNijmegenThe Netherlands
| | - Enrique Asin‐Garcia
- Laboratory of Systems and Synthetic BiologyWageningen University & ResearchWageningenThe Netherlands
| | - Vitor AP Martins dos Santos
- Laboratory of Systems and Synthetic BiologyWageningen University & ResearchWageningenThe Netherlands
- LifeGlimmer GmbHBerlinGermany
| | - Laurens Landeweerd
- Institute for Science in SocietyRadboud UniversityNijmegenThe Netherlands
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25
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Abstract
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Biocontainment is an essential feature
when deploying genetically
modified organisms (GMOs) in open system applications, as variants
escaping their intended operating environments could negatively impact
ecosystems and human health. To avoid breaches resulting from metabolic
cross-feeding, horizontal gene transfer, and/or genetic mutations,
synthetic auxotrophs have been engineered to become dependent on exogenously
supplied xenobiotics, such as noncanonical amino acids (ncAAs). The
incorporation of these abiological building blocks into essential
proteins constitutes a first step toward constructing xenobiological
barriers between GMOs and their environments. To transition synthetic
auxotrophs further away from familiar biology, we demonstrate how
bacterial growth can be confined by transition-metal complexes that
catalyze the formation of an essential ncAA through new-to-nature
reactions. Specifically, using a homogeneous ruthenium complex enabled
us to localize bacterial growth on solid media, while heterogeneous
palladium nanoparticles could be recycled and deployed up to five
consecutive times to ensure the survival of synthetic auxotrophs in
liquid cultures.
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Affiliation(s)
- Rudy Rubini
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Clemens Mayer
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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26
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Kim D, Lee JW. Genetic Biocontainment Systems for the Safe Use of Engineered Microorganisms. BIOTECHNOL BIOPROC E 2020. [DOI: 10.1007/s12257-020-0070-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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27
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Yoo JI, Seppälä S, OʼMalley MA. Engineered fluoride sensitivity enables biocontainment and selection of genetically-modified yeasts. Nat Commun 2020; 11:5459. [PMID: 33122649 PMCID: PMC7596524 DOI: 10.1038/s41467-020-19271-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 10/02/2020] [Indexed: 12/24/2022] Open
Abstract
Biocontainment systems are needed to neutralize genetically modified organisms (GMOs) that pose ecological threats outside of controlled environments. In contrast, benign selection markers complement GMOs with reduced fitness. Benign selection agents serve as alternatives to antibiotics, which are costly and risk spread of antibiotic resistance. Here, we present a yeast biocontainment strategy leveraging engineered fluoride sensitivity and DNA vectors enabling use of fluoride as a selection agent. The biocontainment system addresses the scarcity of platforms available for yeast despite their prevalent use in industry and academia. In the absence of fluoride, the biocontainment strain exhibits phenotypes nearly identical to those of the wildtype strain. Low fluoride concentrations severely inhibit biocontainment strain growth, which is restored upon introduction of fluoride-based vectors. The biocontainment strategy is stringent, easily implemented, and applicable to several eukaryotes. Further, the DNA vectors enable genetic engineering at reduced costs and eliminate risks of propagating antibiotic resistance. Non-antibiotic selection systems could also serve as biocontainment strategies. Here the authors present a fluoride sensitivity selection system for use in yeast.
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Affiliation(s)
- Justin I Yoo
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Susanna Seppälä
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Michelle A OʼMalley
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, CA, 93106, USA.
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28
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Abstract
Preventing the escape of hazardous genes from genetically modified organisms (GMOs) into the environment is one of the most important issues in biotechnology research. Various strategies were developed to create "genetic firewalls" that prevent the leakage of GMOs; however, they were not specially designed to prevent the escape of genes. To address this issue, we developed amino acid (AA)-swapped genetic codes orthogonal to the standard genetic code, namely SL (Ser and Leu were swapped) and SLA genetic codes (Ser, Leu, and Ala were swapped). From mRNAs encoded by the AA-swapped genetic codes, functional proteins were only synthesized in translation systems featuring the corresponding genetic codes. These results clearly demonstrated the orthogonality of the AA-swapped genetic codes against the standard genetic code and their potential to function as "genetic firewalls for genes". Furthermore, we propose "a codon-bypass strategy" to develop a GMO with an AA-swapped genetic code.
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Affiliation(s)
- Tomoshige Fujino
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, 464-8603, Japan
| | - Masahiro Tozaki
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, 464-8603, Japan
| | - Hiroshi Murakami
- Department of Biomolecular Engineering, Graduate School of Engineering, Nagoya University, Nagoya, 464-8603, Japan
- Institute of Nano-Life-Systems, Institutes of Innovation for Future Society, Nagoya University, Nagoya, 464-8603, Japan
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29
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Challenges & opportunities for phage-based in situ microbiome engineering in the gut. J Control Release 2020; 326:106-119. [DOI: 10.1016/j.jconrel.2020.06.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 06/14/2020] [Accepted: 06/15/2020] [Indexed: 12/16/2022]
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30
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Stirling F, Silver PA. Controlling the Implementation of Transgenic Microbes: Are We Ready for What Synthetic Biology Has to Offer? Mol Cell 2020; 78:614-623. [PMID: 32442504 PMCID: PMC7307494 DOI: 10.1016/j.molcel.2020.03.034] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/24/2020] [Accepted: 03/26/2020] [Indexed: 12/13/2022]
Abstract
Synthetic biology has promised and delivered on an impressive array of applications based on genetically modified microorganisms. While novel biotechnology undoubtedly offers benefits, like all new technology, precautions should be considered during implementation to reduce the risk of both known and unknown adverse effects. To achieve containment of transgenic microorganisms, confidence to a near-scientific certainty that they cannot transfer their transgenic genes to other organisms, and that they cannot survive to propagate in unintended environments, is a priority. Here, we present an in-depth summary of biological containment systems for micro-organisms published to date, including the production of a genetic firewall through genome recoding and physical containment of microbes using auxotrophies, regulation of essential genes, and expression of toxic genes. The level of containment required to consider a transgenic organism suitable for deployment is discussed, as well as standards of practice for developing new containment systems.
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Affiliation(s)
- Finn Stirling
- Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Warren Alpert 536, Boston, MA 02115, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, 5th Floor, Boston, MA 02115, USA
| | - Pamela A Silver
- Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Warren Alpert 536, Boston, MA 02115, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, 5th Floor, Boston, MA 02115, USA.
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31
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Asin-Garcia E, Kallergi A, Landeweerd L, Martins Dos Santos VAP. Genetic Safeguards for Safety-by-design: So Close Yet So Far. Trends Biotechnol 2020; 38:1308-1312. [PMID: 32402415 DOI: 10.1016/j.tibtech.2020.04.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/01/2020] [Accepted: 04/13/2020] [Indexed: 01/10/2023]
Abstract
Safety-by-design (SbD) is paramount for risk management in synthetic biology, with genetic safeguards being a key technology for its implementation. While attractive in theory, the integration of genetic safeguards into SbD strategies is rarely exercised in practice, despite technological advances. Here we question why and what might be done about it.
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Affiliation(s)
- Enrique Asin-Garcia
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, 6708, WE, The Netherlands
| | - Amalia Kallergi
- Institute for Science in Society, Radboud University, Nijmegen, 6500, GL, The Netherlands
| | - Laurens Landeweerd
- Institute for Science in Society, Radboud University, Nijmegen, 6500, GL, The Netherlands
| | - Vitor A P Martins Dos Santos
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, 6708, WE, The Netherlands; LifeGlimmer GmbH, Berlin, Germany.
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32
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Altermann E, Hickey WJ. Grand Challenges in Microbiotechnology: Through the Prism of Microbiotechnology. Front Microbiol 2020; 11:430. [PMID: 32265872 PMCID: PMC7099634 DOI: 10.3389/fmicb.2020.00430] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 02/28/2020] [Indexed: 12/14/2022] Open
Affiliation(s)
- Eric Altermann
- AgResearch, Palmerston North, New Zealand.,Riddet Institute, Massey University, Palmerston North, New Zealand
| | - William J Hickey
- Department of Soil Science, University of Wisconsin, Madison, WI, United States
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Nuzzo A, Puccio S, Martina C, Pietrangeli B, Martinez GA, Bertin L, Mancini M, Fava F, Zanaroli G. Containment of a genetically modified microorganism by an activated sludge system. N Biotechnol 2020; 55:58-64. [DOI: 10.1016/j.nbt.2019.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 09/10/2019] [Accepted: 10/02/2019] [Indexed: 01/07/2023]
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Conde-Pueyo N, Vidiella B, Sardanyés J, Berdugo M, Maestre FT, de Lorenzo V, Solé R. Synthetic Biology for Terraformation Lessons from Mars, Earth, and the Microbiome. Life (Basel) 2020; 10:E14. [PMID: 32050455 PMCID: PMC7175242 DOI: 10.3390/life10020014] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 01/27/2020] [Accepted: 02/03/2020] [Indexed: 12/17/2022] Open
Abstract
What is the potential for synthetic biology as a way of engineering, on a large scale, complex ecosystems? Can it be used to change endangered ecological communities and rescue them to prevent their collapse? What are the best strategies for such ecological engineering paths to succeed? Is it possible to create stable, diverse synthetic ecosystems capable of persisting in closed environments? Can synthetic communities be created to thrive on planets different from ours? These and other questions pervade major future developments within synthetic biology. The goal of engineering ecosystems is plagued with all kinds of technological, scientific and ethic problems. In this paper, we consider the requirements for terraformation, i.e., for changing a given environment to make it hospitable to some given class of life forms. Although the standard use of this term involved strategies for planetary terraformation, it has been recently suggested that this approach could be applied to a very different context: ecological communities within our own planet. As discussed here, this includes multiple scales, from the gut microbiome to the entire biosphere.
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Affiliation(s)
- Nuria Conde-Pueyo
- ICREA-Complex Systems Lab, Universitat Pompeu Fabra, Plaça de la Mercè, 10, 08002 Barcelona, Spain; (B.V.); (M.B.)
- Institut de Biologia Evolutiva, UPF-CSIC, 08003 Barcelona, Spain
| | - Blai Vidiella
- ICREA-Complex Systems Lab, Universitat Pompeu Fabra, Plaça de la Mercè, 10, 08002 Barcelona, Spain; (B.V.); (M.B.)
- Institut de Biologia Evolutiva, UPF-CSIC, 08003 Barcelona, Spain
| | - Josep Sardanyés
- Centre de Recerca Matemàtica, Campus UAB Edifici C, 08193 Bellaterra, Barcelona, Spain;
- Barcelona Graduate School of Mathematics (BGSMath), Campus UAB Edifici C, 08193 Bellaterra, Barcelona, Spain
| | - Miguel Berdugo
- ICREA-Complex Systems Lab, Universitat Pompeu Fabra, Plaça de la Mercè, 10, 08002 Barcelona, Spain; (B.V.); (M.B.)
- Institut de Biologia Evolutiva, UPF-CSIC, 08003 Barcelona, Spain
- Departamento de Ecología and Instituto Multidisciplinar para el Estudio del Medio “Ramon Margalef”, Universidad de Alicante, Carr. de San Vicente del Raspeig, s/n, 03690 San Vicente del Raspeig, Alicante, Spain;
| | - Fernando T. Maestre
- Departamento de Ecología and Instituto Multidisciplinar para el Estudio del Medio “Ramon Margalef”, Universidad de Alicante, Carr. de San Vicente del Raspeig, s/n, 03690 San Vicente del Raspeig, Alicante, Spain;
| | - Victor de Lorenzo
- Systems and Synthetic Biology Program, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, 28049 Madrid, Spain;
| | - Ricard Solé
- ICREA-Complex Systems Lab, Universitat Pompeu Fabra, Plaça de la Mercè, 10, 08002 Barcelona, Spain; (B.V.); (M.B.)
- Institut de Biologia Evolutiva, UPF-CSIC, 08003 Barcelona, Spain
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
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35
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Clark M, Maselko M. Transgene Biocontainment Strategies for Molecular Farming. FRONTIERS IN PLANT SCIENCE 2020; 11:210. [PMID: 32194598 PMCID: PMC7063990 DOI: 10.3389/fpls.2020.00210] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 02/11/2020] [Indexed: 05/21/2023]
Abstract
Advances in plant synthetic biology promise to introduce novel agricultural products in the near future. 'Molecular farms' will include crops engineered to produce medications, vaccines, biofuels, industrial enzymes, and other high value compounds. These crops have the potential to reduce costs while dramatically increasing scales of synthesis and provide new economic opportunities to farmers. Current transgenic crops may be considered safe given their long-standing use, however, some applications of molecular farming may pose risks to human health and the environment. Unwanted gene flow from engineered crops could potentially contaminate the food supply, and affect wildlife. There is also potential for unwanted gene flow into engineered crops which may alter their ability to produce compounds of interest. Here, we briefly discuss the applications of molecular farming and explore the various genetic and physical methods that can be used for transgene biocontainment. As yet, no technology can be applied to all crop species, such that a combination of approaches may be necessary. Effective biocontainment is needed to enable large scale molecular farming.
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Affiliation(s)
- Michael Clark
- Applied Biosciences, Macquarie University, North Ryde, NSW, Australia
| | - Maciej Maselko
- Applied Biosciences, Macquarie University, North Ryde, NSW, Australia
- CSIRO Health and Biosecurity, Canberra, ACT, Australia
- CSIRO Synthetic Biology Future Science Platform, Brisbane, QLD, Australia
- *Correspondence: Maciej Maselko,
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36
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Rycroft T, Hamilton K, Haas CN, Linkov I. A quantitative risk assessment method for synthetic biology products in the environment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 696:133940. [PMID: 31446290 DOI: 10.1016/j.scitotenv.2019.133940] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/13/2019] [Accepted: 08/14/2019] [Indexed: 06/10/2023]
Abstract
The need to prevent possible adverse environmental health impacts resulting from synthetic biology (SynBio) products is widely acknowledged in both the SynBio risk literature and the global regulatory community. To-date, however, discussions of potential risks of SynBio products have been largely speculative, and the limited attempts to characterize the risks of SynBio products have been non-uniform and entirely qualitative. As the SynBio discipline continues to accelerate and bring forth novel, highly-engineered life forms, a standardized risk assessment framework will become critical for ensuring that the environmental risks of these products are characterized in a consistent, reliable, and objective manner that incorporates all SynBio-unique risk factors. In their current forms, established risk assessment frameworks - including those that address traditional genetically modified organisms - fall short of the features required of this standard framework. To address this gap, we propose the Quantitative Risk Assessment Method for Synthetic Biology Products (QRA-SynBio) - an incremental build on established risk assessment methodologies that supplements traditional paradigms with the SynBio risk factors that are currently absent, and necessitates quantitative analysis for more transparent and objective risk characterizations. We demonstrate through a hypothetical case study that the proposed framework facilitates defensible quantification of the environmental risks of SynBio products in both foreseeable and hypothetical use scenarios. Additionally, we show how the quantitative nature of the proposed method can promote increased experimental investigation into the true likelihood of hazard and exposure parameters and highlight the most sensitive parameters where uncertainty should be reduced, ultimately leading to more targeted SynBio risk research and yielding more precise characterizations of risk.
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Affiliation(s)
- Taylor Rycroft
- Environmental Laboratory, U.S. Army Engineer Research and Development Center, Concord, MA, USA.
| | - Kerry Hamilton
- School for Sustainable Engineering and the Built Environment & The Biodesign Institute Center for Environmental Health Engineering, Arizona State University, Tempe, AZ, USA
| | - Charles N Haas
- Department of Civil, Architectural and Environmental Engineering, Drexel University, Philadelphia, PA, USA
| | - Igor Linkov
- Environmental Laboratory, U.S. Army Engineer Research and Development Center, Concord, MA, USA
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37
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Zhou Y, Sun T, Chen Z, Song X, Chen L, Zhang W. Development of a New Biocontainment Strategy in Model Cyanobacterium Synechococcus Strains. ACS Synth Biol 2019; 8:2576-2584. [PMID: 31577416 DOI: 10.1021/acssynbio.9b00282] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Recent synthetic biology efforts have raised biosafety concerns for possible release of engineered cyanobacteria into natural environments. To address the issues, we developed a controllable metal ion induced biocontainment system for two model cyanobacteria. First, six ion-inducible promoters were respectively evaluated in both Synechococcus elongatus PCC 7942 and the fast-growing cyanobacterium Synechococcus elongatus UTEX 2973, leading to the identification of an iron ion-repressed promoter PisiAB with low leakage and a reduction-fold of 5.4 and 7.9, respectively. Second, holin-endolysin and nuclease NucA systems were introduced, the inhibition rate of which against two Synechococcus strains varied from 61% to 86.4%. Third, two toxin/antitoxin modules were identified capable of inducing programmed suicide in both Synechococcus strains after induction. Furthermore, an escape experiment was conducted and the results showed that the system was able to achieve an escape frequency below the detection limit of 10-9 after 3 days' duration, demonstrating the strategy integrating iron ion-inducible promoter PisiAB and that toxin/antitoxin modules could be a useful tool for cyanobacterium biocontainment.
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Affiliation(s)
- Yuqing Zhou
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin, 300072, P. R. China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, P. R. China
| | | | - Zixi Chen
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin, 300072, P. R. China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, P. R. China
| | | | - Lei Chen
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin, 300072, P. R. China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, P. R. China
| | - Weiwen Zhang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering, Ministry of Education of China, Tianjin, 300072, P. R. China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, P. R. China
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38
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Schiemann J, Dietz-Pfeilstetter A, Hartung F, Kohl C, Romeis J, Sprink T. Risk Assessment and Regulation of Plants Modified by Modern Biotechniques: Current Status and Future Challenges. ANNUAL REVIEW OF PLANT BIOLOGY 2019; 70:699-726. [PMID: 30822113 DOI: 10.1146/annurev-arplant-050718-100025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
This review describes the current status and future challenges of risk assessment and regulation of plants modified by modern biotechniques, namely genetic engineering and genome editing. It provides a general overview of the biosafety and regulation of genetically modified plants and details different regulatory frameworks with a focus on the European situation. The environmental risk and safety assessment of genetically modified plants is explained, and aspects of toxicological assessments are discussed, especially the controversial debate in Europe on the added scientific value of untargeted animal feeding studies. Because RNA interference (RNAi) is increasingly explored for commercial applications, the risk and safety assessment of RNAi-based genetically modified plants is also elucidated. The production, detection, and identification of genome-edited plants are described. Recent applications of modern biotechniques, namely synthetic biology and gene drives, are discussed, and a short outlook on the future follows.
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Affiliation(s)
- Joachim Schiemann
- Institute for Biosafety in Plant Biotechnology, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, 06484 Quedlinburg, Germany;
| | - Antje Dietz-Pfeilstetter
- Institute for Biosafety in Plant Biotechnology, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, 06484 Quedlinburg, Germany;
| | - Frank Hartung
- Institute for Biosafety in Plant Biotechnology, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, 06484 Quedlinburg, Germany;
| | - Christian Kohl
- Institute for Biosafety in Plant Biotechnology, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, 06484 Quedlinburg, Germany;
| | - Jörg Romeis
- Research Division Agroecology and Environment, Agroscope, 8046 Zurich, Switzerland
| | - Thorben Sprink
- Institute for Biosafety in Plant Biotechnology, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, 06484 Quedlinburg, Germany;
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39
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Jin X, Park OJ, Hong SH. Incorporation of non-standard amino acids into proteins: challenges, recent achievements, and emerging applications. Appl Microbiol Biotechnol 2019; 103:2947-2958. [PMID: 30790000 PMCID: PMC6449208 DOI: 10.1007/s00253-019-09690-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 02/07/2019] [Accepted: 02/08/2019] [Indexed: 12/19/2022]
Abstract
The natural genetic code only allows for 20 standard amino acids in protein translation, but genetic code reprogramming enables the incorporation of non-standard amino acids (NSAAs). Proteins containing NSAAs provide enhanced or novel properties and open diverse applications. With increased attention to the recent advancements in synthetic biology, various improved and novel methods have been developed to incorporate single and multiple distinct NSAAs into proteins. However, various challenges remain in regard to NSAA incorporation, such as low yield and misincorporation. In this review, we summarize the recent efforts to improve NSAA incorporation by utilizing orthogonal translational system optimization, cell-free protein synthesis, genomically recoded organisms, artificial codon boxes, quadruplet codons, and orthogonal ribosomes, before closing with a discussion of the emerging applications of NSAA incorporation.
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Affiliation(s)
- Xing Jin
- Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Oh-Jin Park
- Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA
- Department of Biological and Chemical Engineering, Yanbian University of Science and Technology, Yanji, Jilin, People's Republic of China
| | - Seok Hoon Hong
- Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA.
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40
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Ma NJ, Hemez CF, Barber KW, Rinehart J, Isaacs FJ. Organisms with alternative genetic codes resolve unassigned codons via mistranslation and ribosomal rescue. eLife 2018; 7:34878. [PMID: 30375330 PMCID: PMC6207430 DOI: 10.7554/elife.34878] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 08/26/2018] [Indexed: 11/13/2022] Open
Abstract
Organisms possessing genetic codes with unassigned codons raise the question of how cellular machinery resolves such codons and how this could impact horizontal gene transfer. Here, we use a genomically recoded Escherichia coli to examine how organisms address translation at unassigned UAG codons, which obstruct propagation of UAG-containing viruses and plasmids. Using mass spectrometry, we show that recoded organisms resolve translation at unassigned UAG codons via near-cognate suppression, dramatic frameshifting from at least −3 to +19 nucleotides, and rescue by ssrA-encoded tmRNA, ArfA, and ArfB. We then demonstrate that deleting tmRNA restores expression of UAG-ending proteins and propagation of UAG-containing viruses and plasmids in the recoded strain, indicating that tmRNA rescue and nascent peptide degradation is the cause of impaired virus and plasmid propagation. The ubiquity of tmRNA homologs suggests that genomic recoding is a promising path for impairing horizontal gene transfer and conferring genetic isolation in diverse organisms. Usually, DNA passes from parent to offspring, vertically down the generations. But not always. In some cases, it can move directly from one organism to another by a process called horizontal gene transfer. In bacteria, this happens when DNA segments pass through a bacterium’s cell wall, which can then be picked up by another bacterium. Because the vast majority of organisms share the same genetic code, the bacteria can read this DNA with ease, as it is in the same biological language. Horizontal gene transfer helps bacteria adapt and evolve to their surroundings, letting them swap and share genetic information that could be useful. The process also poses a threat to human health because the DNA that bacteria share can help spread antibiotic resistance. However, some organisms use an alternative genetic code, which obstructs horizontal gene transfer. They cannot read the DNA transmitted to them, because it is in a different ‘biological language’. The mechanism of how this language barrier works has been poorly understood until now. Ma, Hemez, Barber et al. investigated this using Escherichia coli bacteria with an artificially alternated genetic code. In this E. coli, one of the three-letter DNA ‘words’ in the sequence is a blank – it does not exist in the bacterium’s biological language. This three-letter DNA word normally corresponds to a particular protein building block. Using a technique called mass spectrometry, Ma et al. analyzed the proteins this E. coli forms. The results showed that it has several strategies to deal with DNA transmitted horizontally into the bacterium. One method is destroying the proteins that are half-created from the DNA, using molecules called tmRNAs. These are part of a rescue system that intervenes when protein translation stalls on the blank word. The tmRNAs help to add a tag to half-formed proteins, marking them for destruction. This mechanism creates a ‘genetic firewall’ that prevents horizontal gene transfer. In organisms engineered to work from an altered genetic code, this helps to isolate them from outside interference. The findings could have applications in creating engineered bacteria that are safer for use in fields such as medicine and biofuel production.
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Affiliation(s)
- Natalie Jing Ma
- Department of Molecular, Cellular & Developmental Biology, Yale University, New Haven, United States.,Systems Biology Institute, Yale University, West Haven, United States
| | - Colin F Hemez
- Systems Biology Institute, Yale University, West Haven, United States.,Department of Biomedical Engineering, Yale University, New Haven, United States
| | - Karl W Barber
- Systems Biology Institute, Yale University, West Haven, United States.,Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, United States
| | - Jesse Rinehart
- Systems Biology Institute, Yale University, West Haven, United States.,Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, United States
| | - Farren J Isaacs
- Department of Molecular, Cellular & Developmental Biology, Yale University, New Haven, United States.,Systems Biology Institute, Yale University, West Haven, United States
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41
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Motomura K, Sano K, Watanabe S, Kanbara A, Gamal Nasser AH, Ikeda T, Ishida T, Funabashi H, Kuroda A, Hirota R. Synthetic Phosphorus Metabolic Pathway for Biosafety and Contamination Management of Cyanobacterial Cultivation. ACS Synth Biol 2018; 7:2189-2198. [PMID: 30203964 DOI: 10.1021/acssynbio.8b00199] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recent progress in genetic engineering and synthetic biology have greatly expanded the production capabilities of cyanobacteria, but concerns regarding biosafety issues and the risk of contamination of cultures in outdoor culture conditions remain to be resolved. With this dual goal in mind, we applied the recently established biological containment strategy based on phosphite (H3PO3, Pt) dependency to the model cyanobacterium Synechococcus elongatus PCC 7942 ( Syn 7942). Pt assimilation capability was conferred on Syn 7942 by the introduction of Pt dehydrogenase (PtxD) and hypophosphite transporter (HtxBCDE) genes that allow the uptake of Pt, but not phosphate (H3PO4, Pi). We then identified and disrupted the two indigenous Pi transporters, pst (Synpcc7942_2441 to 2445) and pit (Synpcc7942_0184). The resultant strain failed to grow on any media containing various types of P compounds other than Pt. The strain did not yield any escape mutants for at least 28 days with a detection limit of 3.6 × 10-11 per colony forming unit, and rapidly lost viability in the absence of Pt. Moreover, growth competition of the Pt-dependent strain with wild-type cyanobacteria revealed that the Pt-dependent strain could dominate in cultures containing Pt as the sole P source. Because Pt is rarely available in aquatic environments this strategy can contribute to both biosafety and contamination management of genetically engineered cyanobacteria.
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Affiliation(s)
- Kei Motomura
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST-ALCA), Chiyoda-ku, Tokyo 102-0076, Japan
| | - Kosuke Sano
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Satoru Watanabe
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST-ALCA), Chiyoda-ku, Tokyo 102-0076, Japan
- Department of Bioscience, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Akihiro Kanbara
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Abdel-Hady Gamal Nasser
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Takeshi Ikeda
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Takenori Ishida
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Hisakage Funabashi
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Akio Kuroda
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST-ALCA), Chiyoda-ku, Tokyo 102-0076, Japan
| | - Ryuichi Hirota
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST-ALCA), Chiyoda-ku, Tokyo 102-0076, Japan
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42
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Daer R, Barrett CM, Melendez EL, Wu J, Tekel SJ, Xu J, Dennison B, Muller R, Haynes KA. Characterization of diverse homoserine lactone synthases in Escherichia coli. PLoS One 2018; 13:e0202294. [PMID: 30138364 PMCID: PMC6107141 DOI: 10.1371/journal.pone.0202294] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 07/03/2018] [Indexed: 11/18/2022] Open
Abstract
Quorum sensing networks have been identified in over one hundred bacterial species to date. A subset of these networks regulate group behaviors, such as bioluminescence, virulence, and biofilm formation, by sending and receiving small molecules called homoserine lactones (HSLs). Bioengineers have incorporated quorum sensing pathways into genetic circuits to connect logical operations. However, the development of higher-order genetic circuitry is inhibited by crosstalk, in which one quorum sensing network responds to HSLs produced by a different network. Here, we report the construction and characterization of a library of ten synthases including some that are expected to produce HSLs that are incompatible with the Lux pathway, and therefore show no crosstalk. We demonstrated their function in a common lab chassis, Escherichia coli BL21, and in two contexts, liquid and solid agar cultures, using decoupled Sender and Receiver pathways. We observed weak or strong stimulation of a Lux receiver by longer-chain or shorter-chain HSL-generating Senders, respectively. We also considered the under-investigated risk of unintentional release of incompletely deactivated HSLs in biological waste. We found that HSL-enriched media treated with bleach were still bioactive, while autoclaving deactivates LuxR induction. This work represents the most extensive comparison of quorum signaling synthases to date and greatly expands the bacterial signaling toolkit while recommending practices for disposal based on empirical, quantitative evidence.
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Affiliation(s)
- René Daer
- Arizona State University, School of Biological and Health Systems Engineering, Tempe, AZ, United States of America
| | - Cassandra M. Barrett
- Arizona State University, School of Biological and Health Systems Engineering, Tempe, AZ, United States of America
| | - Ernesto Luna Melendez
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States of America
| | - Jiaqi Wu
- School of Computing, Informatics, and Decision Systems Engineering, Arizona State University, Tempe, AZ, United States of America
- School of Life Sciences, Arizona State University, Tempe, AZ, United States of America
| | - Stefan J. Tekel
- Arizona State University, School of Biological and Health Systems Engineering, Tempe, AZ, United States of America
| | - Jimmy Xu
- School of Life Sciences, Arizona State University, Tempe, AZ, United States of America
- School of Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ, United States of America
| | - Brady Dennison
- School of Life Sciences, Arizona State University, Tempe, AZ, United States of America
| | - Ryan Muller
- School of Life Sciences, Arizona State University, Tempe, AZ, United States of America
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, United States of America
| | - Karmella A. Haynes
- Arizona State University, School of Biological and Health Systems Engineering, Tempe, AZ, United States of America
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43
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Whitford CM, Dymek S, Kerkhoff D, März C, Schmidt O, Edich M, Droste J, Pucker B, Rückert C, Kalinowski J. Auxotrophy to Xeno-DNA: an exploration of combinatorial mechanisms for a high-fidelity biosafety system for synthetic biology applications. J Biol Eng 2018; 12:13. [PMID: 30123321 PMCID: PMC6090650 DOI: 10.1186/s13036-018-0105-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 06/25/2018] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Biosafety is a key aspect in the international Genetically Engineered Machine (iGEM) competition, which offers student teams an amazing opportunity to pursue their own research projects in the field of Synthetic Biology. iGEM projects often involve the creation of genetically engineered bacterial strains. To minimize the risks associated with bacterial release, a variety of biosafety systems were constructed, either to prevent survival of bacteria outside the lab or to hinder horizontal or vertical gene transfer. MAIN BODY Physical containment methods such as bioreactors or microencapsulation are considered the first safety level. Additionally, various systems involving auxotrophies for both natural and synthetic compounds have been utilized by iGEM teams in recent years. Combinatorial systems comprising multiple auxotrophies have been shown to reduced escape frequencies below the detection limit. Furthermore, a number of natural toxin-antitoxin systems can be deployed to kill cells under certain conditions. Additionally, parts of naturally occurring toxin-antitoxin systems can be used for the construction of 'kill switches' controlled by synthetic regulatory modules, allowing control of cell survival. Kill switches prevent cell survival but do not completely degrade nucleic acids. To avoid horizontal gene transfer, multiple mechanisms to cleave nucleic acids can be employed, resulting in 'self-destruction' of cells. Changes in light or temperature conditions are powerful regulators of gene expression and could serve as triggers for kill switches or self-destruction systems. Xenobiology-based containment uses applications of Xeno-DNA, recoded codons and non-canonical amino acids to nullify the genetic information of constructed cells for wild type organisms. A 'minimal genome' approach brings the opportunity to reduce the genome of a cell to only genes necessary for survival under lab conditions. Such cells are unlikely to survive in the natural environment and are thus considered safe hosts. If suitable for the desired application, a shift to cell-free systems based on Xeno-DNA may represent the ultimate biosafety system. CONCLUSION Here we describe different containment approaches in synthetic biology, ranging from auxotrophies to minimal genomes, which can be combined to significantly improve reliability. Since the iGEM competition greatly increases the number of people involved in synthetic biology, we will focus especially on biosafety systems developed and applied in the context of the iGEM competition.
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Affiliation(s)
| | - Saskia Dymek
- Center for Biotechnology, Bielefeld University, 33615 Bielefeld, Germany
| | - Denise Kerkhoff
- Center for Biotechnology, Bielefeld University, 33615 Bielefeld, Germany
| | - Camilla März
- Center for Biotechnology, Bielefeld University, 33615 Bielefeld, Germany
| | - Olga Schmidt
- Center for Biotechnology, Bielefeld University, 33615 Bielefeld, Germany
| | - Maximilian Edich
- Center for Biotechnology, Bielefeld University, 33615 Bielefeld, Germany
| | - Julian Droste
- Center for Biotechnology, Bielefeld University, 33615 Bielefeld, Germany
- Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Boas Pucker
- Center for Biotechnology, Bielefeld University, 33615 Bielefeld, Germany
- Faculty of Biology, Bielefeld University, Bielefeld, Germany
- Present address: Evolution and Diversity, Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Christian Rückert
- Center for Biotechnology, Bielefeld University, 33615 Bielefeld, Germany
- Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Jörn Kalinowski
- Center for Biotechnology, Bielefeld University, 33615 Bielefeld, Germany
- Faculty of Biology, Bielefeld University, Bielefeld, Germany
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44
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Next-generation biocontainment systems for engineered organisms. Nat Chem Biol 2018; 14:530-537. [PMID: 29769737 DOI: 10.1038/s41589-018-0056-x] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 03/09/2018] [Indexed: 12/14/2022]
Abstract
The increasing use of engineered organisms for industrial, clinical, and environmental applications poses a growing risk of spreading hazardous biological entities into the environment. To address this biosafety issue, significant effort has been invested in creating ways to confine these organisms and transgenic materials. Emerging technologies in synthetic biology involving genetic circuit engineering, genome editing, and gene expression regulation have led to the development of novel biocontainment systems. In this perspective, we highlight recent advances in biocontainment and suggest a number of approaches for future development, which may be applied to overcome remaining challenges in safeguard implementation.
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45
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Kenny DJ, Balskus EP. Engineering chemical interactions in microbial communities. Chem Soc Rev 2018; 47:1705-1729. [PMID: 29210396 DOI: 10.1039/c7cs00664k] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Microbes living within host-associated microbial communities (microbiotas) rely on chemical communication to interact with surrounding organisms. These interactions serve many purposes, from supplying the multicellular host with nutrients to antagonizing invading pathogens, and breakdown of chemical signaling has potentially negative consequences for both the host and microbiota. Efforts to engineer microbes to take part in chemical interactions represent a promising strategy for modulating chemical signaling within these complex communities. In this review, we discuss prominent examples of chemical interactions found within host-associated microbial communities, with an emphasis on the plant-root microbiota and the intestinal microbiota of animals. We then highlight how an understanding of such interactions has guided efforts to engineer microbes to participate in chemical signaling in these habitats. We discuss engineering efforts in the context of chemical interactions that enable host colonization, promote host health, and exclude pathogens. Finally, we describe prominent challenges facing this field and propose new directions for future engineering efforts.
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Affiliation(s)
- Douglas J Kenny
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
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46
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Clark RL, Gordon GC, Bennett NR, Lyu H, Root TW, Pfleger BF. High-CO 2 Requirement as a Mechanism for the Containment of Genetically Modified Cyanobacteria. ACS Synth Biol 2018; 7:384-391. [PMID: 29320853 DOI: 10.1021/acssynbio.7b00377] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
As researchers engineer cyanobacteria for biotechnological applications, we must consider potential environmental release of these organisms. Previous theoretical work has considered cyanobacterial containment through elimination of the CO2-concentrating mechanism (CCM) to impose a high-CO2 requirement (HCR), which could be provided in the cultivation environment but not in the surroundings. In this work, we experimentally implemented an HCR containment mechanism in Synechococcus sp. strain PCC7002 (PCC7002) through deletion of carboxysome shell proteins and showed that this mechanism contained cyanobacteria in a 5% CO2 environment. We considered escape through horizontal gene transfer (HGT) and reduced the risk of HGT escape by deleting competence genes. We showed that the HCR containment mechanism did not negatively impact the performance of a strain of PCC7002 engineered for L-lactate production. We showed through coculture experiments of HCR strains with ccm-containing strains that this HCR mechanism reduced the frequency of escape below the NIH recommended limit for recombinant organisms of one escape event in 108 CFU.
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Affiliation(s)
- Ryan L. Clark
- Department
of Chemical and Biological Engineering, University of Wisconsin − Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Gina C. Gordon
- Department
of Chemical and Biological Engineering, University of Wisconsin − Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
- Microbiology
Doctoral Training Program, University of Wisconsin − Madison, 1550 Linden Drive, Madison, Wisconsin 53706, United States
| | - Nathaniel R. Bennett
- Department
of Chemical and Biological Engineering, University of Wisconsin − Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Haoxiang Lyu
- Department
of Chemical and Biological Engineering, University of Wisconsin − Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Thatcher W. Root
- Department
of Chemical and Biological Engineering, University of Wisconsin − Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Brian F. Pfleger
- Department
of Chemical and Biological Engineering, University of Wisconsin − Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
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47
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de Lorenzo V, Schmidt M. Biological standards for the Knowledge-Based BioEconomy: What is at stake. N Biotechnol 2018; 40:170-180. [DOI: 10.1016/j.nbt.2017.05.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 05/03/2017] [Indexed: 02/07/2023]
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48
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Lau YH, Stirling F, Kuo J, Karrenbelt MAP, Chan YA, Riesselman A, Horton CA, Schäfer E, Lips D, Weinstock MT, Gibson DG, Way JC, Silver PA. Large-scale recoding of a bacterial genome by iterative recombineering of synthetic DNA. Nucleic Acids Res 2017; 45:6971-6980. [PMID: 28499033 PMCID: PMC5499800 DOI: 10.1093/nar/gkx415] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 05/02/2017] [Indexed: 01/02/2023] Open
Abstract
The ability to rewrite large stretches of genomic DNA enables the creation of new organisms with customized functions. However, few methods currently exist for accumulating such widespread genomic changes in a single organism. In this study, we demonstrate a rapid approach for rewriting bacterial genomes with modified synthetic DNA. We recode 200 kb of the Salmonella typhimurium LT2 genome through a process we term SIRCAS (stepwise integration of rolling circle amplified segments), towards constructing an attenuated and genetically isolated bacterial chassis. The SIRCAS process involves direct iterative recombineering of 10–25 kb synthetic DNA constructs which are assembled in yeast and amplified by rolling circle amplification. Using SIRCAS, we create a Salmonella with 1557 synonymous leucine codon replacements across 176 genes, the largest number of cumulative recoding changes in a single bacterial strain to date. We demonstrate reproducibility over sixteen two-day cycles of integration and parallelization for hierarchical construction of a synthetic genome by conjugation. The resulting recoded strain grows at a similar rate to the wild-type strain and does not exhibit any major growth defects. This work is the first instance of synthetic bacterial recoding beyond the Escherichia coli genome, and reveals that Salmonella is remarkably amenable to genome-scale modification.
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Affiliation(s)
- Yu Heng Lau
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, 5th Floor, Boston, MA 02115, USA.,Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Alpert 536, Boston, MA 02115, USA
| | - Finn Stirling
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, 5th Floor, Boston, MA 02115, USA.,Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Alpert 536, Boston, MA 02115, USA
| | - James Kuo
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, 5th Floor, Boston, MA 02115, USA.,Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Alpert 536, Boston, MA 02115, USA
| | - Michiel A P Karrenbelt
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, 5th Floor, Boston, MA 02115, USA.,Systems and Synthetic Biology, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, The Netherlands
| | - Yujia A Chan
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, 5th Floor, Boston, MA 02115, USA.,Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Alpert 536, Boston, MA 02115, USA
| | - Adam Riesselman
- Program in Biomedical Informatics, Harvard Medical School, Boston, MA 02115, USA
| | - Connor A Horton
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, 5th Floor, Boston, MA 02115, USA.,Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Alpert 536, Boston, MA 02115, USA
| | - Elena Schäfer
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, 5th Floor, Boston, MA 02115, USA.,Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Alpert 536, Boston, MA 02115, USA
| | - David Lips
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, 5th Floor, Boston, MA 02115, USA.,Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Alpert 536, Boston, MA 02115, USA
| | - Matthew T Weinstock
- Synthetic Genomics, Inc., 11149 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Daniel G Gibson
- Synthetic Genomics, Inc., 11149 North Torrey Pines Road, La Jolla, CA 92037, USA.,Synthetic Biology and Bioenergy Group, J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, CA 92037, USA
| | - Jeffrey C Way
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, 5th Floor, Boston, MA 02115, USA.,Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Alpert 536, Boston, MA 02115, USA
| | - Pamela A Silver
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, 5th Floor, Boston, MA 02115, USA.,Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Alpert 536, Boston, MA 02115, USA
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49
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Abstract
Evolution in the form of selective breeding has long been harnessed as a useful tool by humans. However, rapid evolution can also be a danger to our health and a stumbling block for biotechnology. Unwanted evolution can underlie the emergence of drug and pesticide resistance, cancer, and weeds. It makes live vaccines and engineered cells inherently unreliable and unpredictable, and therefore potentially unsafe. Yet, there are strategies that have been and can possibly be used to stop or slow many types of evolution. We review and classify existing population genetics-inspired methods for arresting evolution. Then, we discuss how genome editing techniques enable a radically new set of approaches to limit evolution.
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50
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Kubyshkin V, Budisa N. Synthetic alienation of microbial organisms by using genetic code engineering: Why and how? Biotechnol J 2017; 12. [PMID: 28671771 DOI: 10.1002/biot.201600097] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 05/19/2017] [Accepted: 05/31/2017] [Indexed: 12/31/2022]
Abstract
The main goal of synthetic biology (SB) is the creation of biodiversity applicable for biotechnological needs, while xenobiology (XB) aims to expand the framework of natural chemistries with the non-natural building blocks in living cells to accomplish artificial biodiversity. Protein and proteome engineering, which overcome limitation of the canonical amino acid repertoire of 20 (+2) prescribed by the genetic code by using non-canonic amino acids (ncAAs), is one of the main focuses of XB research. Ideally, estranging the genetic code from its current form via systematic introduction of ncAAs should enable the development of bio-containment mechanisms in synthetic cells potentially endowing them with a "genetic firewall" i.e. orthogonality which prevents genetic information transfer to natural systems. Despite rapid progress over the past two decades, it is not yet possible to completely alienate an organism that would use and maintain different genetic code associations permanently. In order to engineer robust bio-contained life forms, the chemical logic behind the amino acid repertoire establishment should be considered. Starting from recent proposal of Hartman and Smith about the genetic code establishment in the RNA world, here the authors mapped possible biotechnological invasion points for engineering of bio-contained synthetic cells equipped with non-canonical functionalities.
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Affiliation(s)
- Vladimir Kubyshkin
- Biocatalysis group, Institute of Chemistry, Technical University of Berlin, Germany
| | - Nediljko Budisa
- Biocatalysis group, Institute of Chemistry, Technical University of Berlin, Germany
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