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Engineering Biology to Construct Microbial Chassis for the Production of Difficult-to-Express Proteins. Int J Mol Sci 2020; 21:ijms21030990. [PMID: 32024292 PMCID: PMC7037952 DOI: 10.3390/ijms21030990] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/28/2020] [Accepted: 01/31/2020] [Indexed: 12/12/2022] Open
Abstract
A large proportion of the recombinant proteins manufactured today rely on microbe-based expression systems owing to their relatively simple and cost-effective production schemes. However, several issues in microbial protein expression, including formation of insoluble aggregates, low protein yield, and cell death are still highly recursive and tricky to optimize. These obstacles are usually rooted in the metabolic capacity of the expression host, limitation of cellular translational machineries, or genetic instability. To this end, several microbial strains having precisely designed genomes have been suggested as a way around the recurrent problems in recombinant protein expression. Already, a growing number of prokaryotic chassis strains have been genome-streamlined to attain superior cellular fitness, recombinant protein yield, and stability of the exogenous expression pathways. In this review, we outline challenges associated with heterologous protein expression, some examples of microbial chassis engineered for the production of recombinant proteins, and emerging tools to optimize the expression of heterologous proteins. In particular, we discuss the synthetic biology approaches to design and build and test genome-reduced microbial chassis that carry desirable characteristics for heterologous protein expression.
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Kurokawa M, Ying BW. Experimental Challenges for Reduced Genomes: The Cell Model Escherichia coli. Microorganisms 2019; 8:E3. [PMID: 31861355 PMCID: PMC7022904 DOI: 10.3390/microorganisms8010003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/11/2019] [Accepted: 12/17/2019] [Indexed: 12/13/2022] Open
Abstract
Genome reduction, as a top-down approach to obtain the minimal genetic information essential for a living organism, has been conducted with bacterial cells for decades. The most popular and well-studied cell models for genome reduction are Escherichia coli strains. As the previous literature intensively introduced the genetic construction and application of the genome-reduced Escherichia coli strains, the present review focuses the design principles and compares the reduced genome collections from the specific viewpoint of growth, which represents a fundamental property of living cells and is an important feature for their biotechnological application. For the extended simplification of the genomic sequences, the approach of experimental evolution and concern for medium optimization are newly proposed. The combination of the current techniques of genomic construction and the newly proposed methodologies could allow us to acquire growing Escherichia coli cells carrying the extensively reduced genome and to address the question of what the minimal genome essential for life is.
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Affiliation(s)
| | - Bei-Wen Ying
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 305-8572 Ibaraki, Japan;
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Ubiquinone Biosynthesis over the Entire O 2 Range: Characterization of a Conserved O 2-Independent Pathway. mBio 2019; 10:mBio.01319-19. [PMID: 31289180 PMCID: PMC6747719 DOI: 10.1128/mbio.01319-19] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In order to colonize environments with large O2 gradients or fluctuating O2 levels, bacteria have developed metabolic responses that remain incompletely understood. Such adaptations have been recently linked to antibiotic resistance, virulence, and the capacity to develop in complex ecosystems like the microbiota. Here, we identify a novel pathway for the biosynthesis of ubiquinone, a molecule with a key role in cellular bioenergetics. We link three uncharacterized genes of Escherichia coli to this pathway and show that the pathway functions independently from O2. In contrast, the long-described pathway for ubiquinone biosynthesis requires O2 as a substrate. In fact, we find that many proteobacteria are equipped with the O2-dependent and O2-independent pathways, supporting that they are able to synthesize ubiquinone over the entire O2 range. Overall, we propose that the novel O2-independent pathway is part of the metabolic plasticity developed by proteobacteria to face various environmental O2 levels. Most bacteria can generate ATP by respiratory metabolism, in which electrons are shuttled from reduced substrates to terminal electron acceptors, via quinone molecules like ubiquinone. Dioxygen (O2) is the terminal electron acceptor of aerobic respiration and serves as a co-substrate in the biosynthesis of ubiquinone. Here, we characterize a novel, O2-independent pathway for the biosynthesis of ubiquinone. This pathway relies on three proteins, UbiT (YhbT), UbiU (YhbU), and UbiV (YhbV). UbiT contains an SCP2 lipid-binding domain and is likely an accessory factor of the biosynthetic pathway, while UbiU and UbiV (UbiU-UbiV) are involved in hydroxylation reactions and represent a novel class of O2-independent hydroxylases. We demonstrate that UbiU-UbiV form a heterodimer, wherein each protein binds a 4Fe-4S cluster via conserved cysteines that are essential for activity. The UbiT, -U, and -V proteins are found in alpha-, beta-, and gammaproteobacterial clades, including several human pathogens, supporting the widespread distribution of a previously unrecognized capacity to synthesize ubiquinone in the absence of O2. Together, the O2-dependent and O2-independent ubiquinone biosynthesis pathways contribute to optimizing bacterial metabolism over the entire O2 range.
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Landon S, Rees-Garbutt J, Marucci L, Grierson C. Genome-driven cell engineering review: in vivo and in silico metabolic and genome engineering. Essays Biochem 2019; 63:267-284. [PMID: 31243142 PMCID: PMC6610458 DOI: 10.1042/ebc20180045] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/19/2019] [Accepted: 05/23/2019] [Indexed: 01/04/2023]
Abstract
Producing 'designer cells' with specific functions is potentially feasible in the near future. Recent developments, including whole-cell models, genome design algorithms and gene editing tools, have advanced the possibility of combining biological research and mathematical modelling to further understand and better design cellular processes. In this review, we will explore computational and experimental approaches used for metabolic and genome design. We will highlight the relevance of modelling in this process, and challenges associated with the generation of quantitative predictions about cell behaviour as a whole: although many cellular processes are well understood at the subsystem level, it has proved a hugely complex task to integrate separate components together to model and study an entire cell. We explore these developments, highlighting where computational design algorithms compensate for missing cellular information and underlining where computational models can complement and reduce lab experimentation. We will examine issues and illuminate the next steps for genome engineering.
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Affiliation(s)
- Sophie Landon
- BrisSynBio, University of Bristol, Bristol BS8 1TQ, U.K
- Department of Engineering Mathematics, University of Bristol, Bristol BS8 1UB, U.K
| | - Joshua Rees-Garbutt
- BrisSynBio, University of Bristol, Bristol BS8 1TQ, U.K
- School of Biological Sciences, University of Bristol, Life Sciences Building, Bristol BS8 1TQ, U.K
| | - Lucia Marucci
- BrisSynBio, University of Bristol, Bristol BS8 1TQ, U.K.
- Department of Engineering Mathematics, University of Bristol, Bristol BS8 1UB, U.K
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1UB, U.K
| | - Claire Grierson
- BrisSynBio, University of Bristol, Bristol BS8 1TQ, U.K.
- School of Biological Sciences, University of Bristol, Life Sciences Building, Bristol BS8 1TQ, U.K
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55
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Identification of a Formate-Dependent Uric Acid Degradation Pathway in Escherichia coli. J Bacteriol 2019; 201:JB.00573-18. [PMID: 30885932 DOI: 10.1128/jb.00573-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 02/28/2019] [Indexed: 01/31/2023] Open
Abstract
Purine is a nitrogen-containing compound that is abundant in nature. In organisms that utilize purine as a nitrogen source, purine is converted to uric acid, which is then converted to allantoin. Allantoin is then converted to ammonia. In Escherichia coli, neither urate-degrading activity nor a gene encoding an enzyme homologous to the known urate-degrading enzymes had previously been found. Here, we demonstrate urate-degrading activity in E. coli We first identified aegA as an E. coli gene involved in oxidative stress tolerance. An examination of gene expression revealed that both aegA and its paralog ygfT are expressed under both microaerobic and anaerobic conditions. The ygfT gene is localized within a chromosomal gene cluster presumably involved in purine catabolism. Accordingly, the expression of ygfT increased in the presence of exogenous uric acid, suggesting that ygfT is involved in urate degradation. Examination of the change of uric acid levels in the growth medium with time revealed urate-degrading activity under microaerobic and anaerobic conditions in the wild-type strain but not in the aegA ygfT double-deletion mutant. Furthermore, AegA- and YgfT-dependent urate-degrading activity was detected only in the presence of formate and formate dehydrogenase H. Collectively, these observations indicate the presence of urate-degrading activity in E. coli that is operational under microaerobic and anaerobic conditions. The activity requires formate, formate dehydrogenase H, and either aegA or ygfT We also identified other putative genes which are involved not only in formate-dependent but also in formate-independent urate degradation and may function in the regulation or cofactor synthesis in purine catabolism.IMPORTANCE The metabolic pathway of uric acid degradation to date has been elucidated only in aerobic environments and is not understood in anaerobic and microaerobic environments. In the current study, we showed that Escherichia coli, a facultative anaerobic organism, uses uric acid as a sole source of nitrogen under anaerobic and microaerobic conditions. We also showed that formate, formate dehydrogenase H, and either AegA or YgfT are involved in uric acid degradation. We propose that formate may act as an electron donor for a uric acid-degrading enzyme in this bacterium.
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Chi H, Wang X, Shao Y, Qin Y, Deng Z, Wang L, Chen S. Engineering and modification of microbial chassis for systems and synthetic biology. Synth Syst Biotechnol 2019; 4:25-33. [PMID: 30560208 PMCID: PMC6290258 DOI: 10.1016/j.synbio.2018.12.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/14/2018] [Accepted: 12/05/2018] [Indexed: 12/14/2022] Open
Abstract
Engineering and modifying synthetic microbial chassis is one of the best ways not only to unravel the fundamental principles of life but also to enhance applications in the health, medicine, agricultural, veterinary, and food industries. The two primary strategies for constructing a microbial chassis are the top-down approach (genome reduction) and the bottom-up approach (genome synthesis). Research programs on this topic have been funded in several countries. The 'Minimum genome factory' (MGF) project was launched in 2001 in Japan with the goal of constructing microorganisms with smaller genomes for industrial use. One of the best examples of the results of this project is E. coli MGF-01, which has a reduced-genome size and exhibits better growth and higher threonine production characteristics than the parental strain [1]. The 'cell factory' project was carried out from 1998 to 2002 in the Fifth Framework Program of the EU (European Union), which tried to comprehensively understand microorganisms used in the application field. One of the outstanding results of this project was the elucidation of proteins secreted by Bacillus subtilis, which was summarized as the 'secretome' [2]. The GTL (Genomes to Life) program began in 2002 in the United States. In this program, researchers aimed to create artificial cells both in silico and in vitro, such as the successful design and synthesis of a minimal bacterial genome by John Craig Venter's group [3]. This review provides an update on recent advances in engineering, modification and application of synthetic microbial chassis, with particular emphasis on the value of learning about chassis as a way to better understand life and improve applications.
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Affiliation(s)
- Haotian Chi
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
- Taihe Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, China
| | - Xiaoli Wang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
| | - Yue Shao
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
| | - Ying Qin
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
| | - Zixin Deng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
| | - Lianrong Wang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
| | - Shi Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
- Taihe Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, China
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Adaptive laboratory evolution of a genome-reduced Escherichia coli. Nat Commun 2019; 10:935. [PMID: 30804335 PMCID: PMC6389913 DOI: 10.1038/s41467-019-08888-6] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 01/31/2019] [Indexed: 12/11/2022] Open
Abstract
Synthetic biology aims to design and construct bacterial genomes harboring the minimum number of genes required for self-replicable life. However, the genome-reduced bacteria often show impaired growth under laboratory conditions that cannot be understood based on the removed genes. The unexpected phenotypes highlight our limited understanding of bacterial genomes. Here, we deploy adaptive laboratory evolution (ALE) to re-optimize growth performance of a genome-reduced strain. The basis for suboptimal growth is the imbalanced metabolism that is rewired during ALE. The metabolic rewiring is globally orchestrated by mutations in rpoD altering promoter binding of RNA polymerase. Lastly, the evolved strain has no translational buffering capacity, enabling effective translation of abundant mRNAs. Multi-omic analysis of the evolved strain reveals transcriptome- and translatome-wide remodeling that orchestrate metabolism and growth. These results reveal that failure of prediction may not be associated with understanding individual genes, but rather from insufficient understanding of the strain's systems biology.
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58
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Zhan J, Jia H, Semchenko EA, Bian Y, Zhou AM, Li Z, Yang Y, Wang J, Sarkar S, Totsika M, Blanchard H, Jen FEC, Ye Q, Haselhorst T, Jennings MP, Seib KL, Zhou Y. Self-derived structure-disrupting peptides targeting methionine aminopeptidase in pathogenic bacteria: a new strategy to generate antimicrobial peptides. FASEB J 2019; 33:2095-2104. [PMID: 30260702 PMCID: PMC6338635 DOI: 10.1096/fj.201700613rr] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 08/27/2018] [Indexed: 11/11/2022]
Abstract
Bacterial infection is one of the leading causes of death in young, elderly, and immune-compromised patients. The rapid spread of multi-drug-resistant (MDR) bacteria is a global health emergency and there is a lack of new drugs to control MDR pathogens. We describe a heretofore-unexplored discovery pathway for novel antibiotics that is based on self-targeting, structure-disrupting peptides. We show that a helical peptide, KFF- EcH3, derived from the Escherichia coli methionine aminopeptidase can disrupt secondary and tertiary structure of this essential enzyme, thereby killing the bacterium (including MDR strains). Significantly, no detectable resistance developed against this peptide. Based on a computational analysis, our study predicted that peptide KFF- EcH3 has the strongest interaction with the structural core of the methionine aminopeptidase. We further used our approach to identify peptide KFF- NgH1 to target the same enzyme from Neisseria gonorrhoeae. This peptide inhibited bacterial growth and was able to treat a gonococcal infection in a human cervical epithelial cell model. These findings present an exciting new paradigm in antibiotic discovery using self-derived peptides that can be developed to target the structures of any essential bacterial proteins.-Zhan, J., Jia, H., Semchenko, E. A., Bian, Y., Zhou, A. M., Li, Z., Yang, Y., Wang, J., Sarkar, S., Totsika, M., Blanchard, H., Jen, F. E.-C., Ye, Q., Haselhorst, T., Jennings, M. P., Seib, K. L., Zhou, Y. Self-derived structure-disrupting peptides targeting methionine aminopeptidase in pathogenic bacteria: a new strategy to generate antimicrobial peptides.
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Affiliation(s)
- Jian Zhan
- Institute for Glycomics, Griffith University, Queensland, Australia
| | - Husen Jia
- Institute for Glycomics, Griffith University, Queensland, Australia
| | | | - Yunqiang Bian
- Shandong Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou, China
| | - Amy M. Zhou
- Queensland Academies–Health Sciences, Southport, Queensland, Australia
| | - Zhixiu Li
- Indiana University School of Informatics, Indiana University–Purdue University Indianapolis, Indianapolis, Indiana, USA
| | - Yuedong Yang
- Institute for Glycomics, Griffith University, Queensland, Australia
| | - Jihua Wang
- Shandong Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou, China
| | - Sohinee Sarkar
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Makrina Totsika
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Helen Blanchard
- Institute for Glycomics, Griffith University, Queensland, Australia
| | - Freda E.-C. Jen
- Institute for Glycomics, Griffith University, Queensland, Australia
| | - Qizhuang Ye
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- School of Medicine, Shenzhen University, Shenzhen, China
| | | | | | - Kate L. Seib
- Institute for Glycomics, Griffith University, Queensland, Australia
| | - Yaoqi Zhou
- Institute for Glycomics, Griffith University, Queensland, Australia
- Shandong Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou, China
- Indiana University School of Informatics, Indiana University–Purdue University Indianapolis, Indianapolis, Indiana, USA
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59
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Calero P, Nikel PI. Chasing bacterial chassis for metabolic engineering: a perspective review from classical to non-traditional microorganisms. Microb Biotechnol 2019; 12:98-124. [PMID: 29926529 PMCID: PMC6302729 DOI: 10.1111/1751-7915.13292] [Citation(s) in RCA: 150] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 05/28/2018] [Accepted: 05/29/2018] [Indexed: 12/27/2022] Open
Abstract
The last few years have witnessed an unprecedented increase in the number of novel bacterial species that hold potential to be used for metabolic engineering. Historically, however, only a handful of bacteria have attained the acceptance and widespread use that are needed to fulfil the needs of industrial bioproduction - and only for the synthesis of very few, structurally simple compounds. One of the reasons for this unfortunate circumstance has been the dearth of tools for targeted genome engineering of bacterial chassis, and, nowadays, synthetic biology is significantly helping to bridge such knowledge gap. Against this background, in this review, we discuss the state of the art in the rational design and construction of robust bacterial chassis for metabolic engineering, presenting key examples of bacterial species that have secured a place in industrial bioproduction. The emergence of novel bacterial chassis is also considered at the light of the unique properties of their physiology and metabolism, and the practical applications in which they are expected to outperform other microbial platforms. Emerging opportunities, essential strategies to enable successful development of industrial phenotypes, and major challenges in the field of bacterial chassis development are also discussed, outlining the solutions that contemporary synthetic biology-guided metabolic engineering offers to tackle these issues.
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Affiliation(s)
- Patricia Calero
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of Denmark2800Kongens LyngbyDenmark
| | - Pablo I. Nikel
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of Denmark2800Kongens LyngbyDenmark
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60
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Yang ZK, Luo H, Zhang Y, Wang B, Gao F. Pan-genomic analysis provides novel insights into the association of E.coli with human host and its minimal genome. Bioinformatics 2018; 35:1987-1991. [DOI: 10.1093/bioinformatics/bty938] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 11/06/2018] [Accepted: 11/08/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Zhi-Kai Yang
- Department of Physics, School of Science
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, China
- SinoGenoMax Co., Ltd./Chinese National Human Genome Center, Beijing, China
| | - Hao Luo
- Department of Physics, School of Science
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, China
| | - Yanming Zhang
- SinoGenoMax Co., Ltd./Chinese National Human Genome Center, Beijing, China
| | - Baijing Wang
- SinoGenoMax Co., Ltd./Chinese National Human Genome Center, Beijing, China
| | - Feng Gao
- Department of Physics, School of Science
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, China
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Abstract
Nitric oxide (NO·) produced by mammalian cells exerts antimicrobial actions that result primarily from the modification of protein thiols (S-nitrosylation) and metal centers. A comprehensive approach was used to identify novel targets of NO· in Salmonella enterica serovar Typhimurium (S. Typhimurium). Newly identified targets include zinc metalloproteins required for DNA replication and repair (DnaG, PriA, and TopA), protein synthesis (AlaS and RpmE), and various metabolic activities (ClpX, GloB, MetE, PepA, and QueC). The cytotoxic actions of free zinc are mitigated by the ZntA and ZitB zinc efflux transporters, which are required for S. Typhimurium resistance to zinc overload and nitrosative stress in vitro Zinc efflux also ameliorates NO·-dependent zinc mobilization following internalization by activated macrophages and is required for virulence in NO·-producing mice, demonstrating that host-derived NO· causes zinc stress in intracellular bacteria.IMPORTANCE Nitric oxide (NO·) is produced by macrophages in response to inflammatory stimuli and restricts the growth of intracellular bacteria. Mechanisms of NO·-dependent antimicrobial actions are incompletely understood. Here, we show that zinc metalloproteins are important targets of NO· in Salmonella, including the DNA replication proteins DnaG and PriA, which were hypothesized to be NO· targets in earlier studies. Like iron, zinc is a cofactor for several essential proteins but is toxic at elevated concentrations. This study demonstrates that NO· mobilizes free zinc in Salmonella and that specific efflux transporters ameliorate the cytotoxic effects of free zinc during infection.
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62
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Iwadate Y, Funabasama N, Kato JI. Involvement of formate dehydrogenases in stationary phase oxidative stress tolerance in Escherichia coli. FEMS Microbiol Lett 2018; 364:4243112. [PMID: 29044403 DOI: 10.1093/femsle/fnx193] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 09/11/2017] [Indexed: 01/24/2023] Open
Abstract
Previously, we constructed a series of reduced-genome strains of Escherichia coli by combining large-scale chromosome deletions and then tested the sensitivity of these strains to the redox-cycling drug menadione. In this study, we analyzed a deletion that increased menadione sensitivity and discovered that loss of selenocysteine synthase genes was responsible for the strain's reduced tolerance to oxidative stress. Mutants of formate dehydrogenases, which are selenocysteine-containing enzymes, were also sensitive to menadione, indicating that these enzymes are involved in oxidative stress during stationary phase, specifically under microaerobic conditions in the presence of glucose. Among three formate dehydrogenases encoded by the E. coli genome, two were responsible for the observed phenotypes: formate dehydrogenase-H and -O. In a mutant of fdhD, which encodes a sulfur transferase that is essential for formate dehydrogenase activity, formate dehydrogenase-O could still contribute to oxidative stress tolerance, revealing a novel role for this protein. Consistent with this, overproduction of the electron transfer subunits of this enzyme, FdoH and FdoI, increased menadione tolerance and supported survival in stationary phase. These results suggested that formate dehydrogenase-O serves as an electron transfer element in glucose metabolism to promote oxidative stress tolerance and survival in stationary phase.
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Affiliation(s)
- Yumi Iwadate
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minamiohsawa, Hachioji, Tokyo 192-0397, Japan
| | - Noriyuki Funabasama
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minamiohsawa, Hachioji, Tokyo 192-0397, Japan
| | - Jun-Ichi Kato
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minamiohsawa, Hachioji, Tokyo 192-0397, Japan
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63
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Mahfouz N, Caucci S, Achatz E, Semmler T, Guenther S, Berendonk TU, Schroeder M. High genomic diversity of multi-drug resistant wastewater Escherichia coli. Sci Rep 2018; 8:8928. [PMID: 29895899 PMCID: PMC5997705 DOI: 10.1038/s41598-018-27292-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 05/18/2018] [Indexed: 12/13/2022] Open
Abstract
Wastewater treatment plants play an important role in the emergence of antibiotic resistance. They provide a hot spot for exchange of resistance within and between species. Here, we analyse and quantify the genomic diversity of the indicator Escherichia coli in a German wastewater treatment plant and we relate it to isolates’ antibiotic resistance. Our results show a surprisingly large pan-genome, which mirrors how rich an environment a treatment plant is. We link the genomic analysis to a phenotypic resistance screen and pinpoint genomic hot spots, which correlate with a resistance phenotype. Besides well-known resistance genes, this forward genomics approach generates many novel genes, which correlated with resistance and which are partly completely unknown. A surprising overall finding of our analyses is that we do not see any difference in resistance and pan genome size between isolates taken from the inflow of the treatment plant and from the outflow. This means that while treatment plants reduce the amount of bacteria released into the environment, they do not reduce the potential for antibiotic resistance of these bacteria.
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Affiliation(s)
| | - Serena Caucci
- Institute for Hydrobiology, TU Dresden, Dresden, Germany.,United Nations University Institute for Integrated Management of Material Fluxes and of Resources, Dresden, Germany
| | | | - Torsten Semmler
- Institute of Microbiology und Epizootics, FU, Berlin, Germany
| | - Sebastian Guenther
- Institute of Microbiology und Epizootics, FU, Berlin, Germany.,Institut für Pharmazie Pharmazeutische Biologie, Ernst-Moritz-Arndt-Universität Greifswald, Greifswald, Germany
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64
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Martínez-Carranza E, Barajas H, Alcaraz LD, Servín-González L, Ponce-Soto GY, Soberón-Chávez G. Variability of Bacterial Essential Genes Among Closely Related Bacteria: The Case of Escherichia coli. Front Microbiol 2018; 9:1059. [PMID: 29910775 PMCID: PMC5992433 DOI: 10.3389/fmicb.2018.01059] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/04/2018] [Indexed: 11/23/2022] Open
Abstract
The definition of bacterial essential genes has been widely pursued using different approaches. Their study has impacted several fields of research such as synthetic biology, the construction of bacteria with minimal chromosomes, the search for new antibiotic targets, or the design of strains with biotechnological applications. Bacterial genomes are mosaics that only share a small subset of gene-sequences (core genome) even among members of the same species. It has been reported that the presence of essential genes is highly variable between closely related bacteria and even among members of the same species, due to the phenomenon known as “non-orthologous gene displacement” that refers to the coding for an essential function by genes with no sequence homology due to horizontal gene transfer (HGT). The existence of dormant forms among bacteria and the high incidence of HGT have been proposed to be driving forces of bacterial evolution, and they might have a role in the low level of conservation of essential genes among related bacteria by non-orthologous gene displacement, but this correlation has not been recognized. The aim of this mini-review is to give a brief overview of the approaches that have been taken to define and study essential genes, and the implications of non-orthologous gene displacement in bacterial evolution, focusing mainly in the case of Escherichia coli. To this end, we reviewed the available literature, and we searched for the presence of the essential genes defined by mutagenesis in the genomes of the 63 best-sequenced E. coli genomes that are available in NCBI database. We could not document specific cases of non-orthologous gene displacement among the E. coli strains analyzed, but we found that the quality of the genome-sequences in the database is not enough to make accurate predictions about the conservation of essential-genes among members of this bacterial species.
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Affiliation(s)
- Enrique Martínez-Carranza
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Hugo Barajas
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Luis-David Alcaraz
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Luis Servín-González
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gabriel-Yaxal Ponce-Soto
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gloria Soberón-Chávez
- Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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65
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Jagmann N, Philipp B. SpoT-Mediated Regulation and Amino Acid Prototrophy Are Essential for Pyocyanin Production During Parasitic Growth of Pseudomonas aeruginosa in a Co-culture Model System With Aeromonas hydrophila. Front Microbiol 2018; 9:761. [PMID: 29720972 PMCID: PMC5915560 DOI: 10.3389/fmicb.2018.00761] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 04/04/2018] [Indexed: 11/17/2022] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa employs its complex quorum sensing (QS) network to regulate the expression of virulence factors such as pyocyanin. Besides cell density, QS in this bacterium is co-regulated by environmental cues. In this study, we employed a previously established co-culture model system to identify metabolic influences that are involved in the regulation of pyocyanin production in P. aeruginosa. In this co-culture consisting of P. aeruginosa and the chitinolytic bacterium Aeromonas hydrophila, parasitic growth of P. aeruginosa is strictly dependent on the production of pyocyanin. We could show that in this co-culture, pyocyanin production is likely induced by the stringent response mediated by SpoT in response to nutrient limitation. Pyocyanin production by stringent response mutants in the co-culture could not be complemented by overexpression of PqsE. Via transposon mutagenesis, several amino acid auxotrophic mutants were identified that were also unable to produce pyocyanin when PqsE was overexpressed or when complementing amino acids were present. The inability to produce pyocyanin even though PqsE was overexpressed was likely a general effect of amino acid auxotrophy. These results show the value of the co-culture approach to identify both extra- and intracellular metabolic influences on QS that might be important in infection processes as well.
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Affiliation(s)
- Nina Jagmann
- Institute for Molecular Microbiology and Biotechnology, University of Münster, Münster, Germany
| | - Bodo Philipp
- Institute for Molecular Microbiology and Biotechnology, University of Münster, Münster, Germany
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66
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Baby V, Lachance JC, Gagnon J, Lucier JF, Matteau D, Knight T, Rodrigue S. Inferring the Minimal Genome of Mesoplasma florum by Comparative Genomics and Transposon Mutagenesis. mSystems 2018; 3:e00198-17. [PMID: 29657968 PMCID: PMC5893858 DOI: 10.1128/msystems.00198-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 03/09/2018] [Indexed: 12/14/2022] Open
Abstract
The creation and comparison of minimal genomes will help better define the most fundamental mechanisms supporting life. Mesoplasma florum is a near-minimal, fast-growing, nonpathogenic bacterium potentially amenable to genome reduction efforts. In a comparative genomic study of 13 M. florum strains, including 11 newly sequenced genomes, we have identified the core genome and open pangenome of this species. Our results show that all of the strains have approximately 80% of their gene content in common. Of the remaining 20%, 17% of the genes were found in multiple strains and 3% were unique to any given strain. On the basis of random transposon mutagenesis, we also estimated that ~290 out of 720 genes are essential for M. florum L1 in rich medium. We next evaluated different genome reduction scenarios for M. florum L1 by using gene conservation and essentiality data, as well as comparisons with the first working approximation of a minimal organism, Mycoplasma mycoides JCVI-syn3.0. Our results suggest that 409 of the 473 M. mycoides JCVI-syn3.0 genes have orthologs in M. florum L1. Conversely, 57 putatively essential M. florum L1 genes have no homolog in M. mycoides JCVI-syn3.0. This suggests differences in minimal genome compositions, even for these evolutionarily closely related bacteria. IMPORTANCE The last years have witnessed the development of whole-genome cloning and transplantation methods and the complete synthesis of entire chromosomes. Recently, the first minimal cell, Mycoplasma mycoides JCVI-syn3.0, was created. Despite these milestone achievements, several questions remain to be answered. For example, is the composition of minimal genomes virtually identical in phylogenetically related species? On the basis of comparative genomics and transposon mutagenesis, we investigated this question by using an alternative model, Mesoplasma florum, that is also amenable to genome reduction efforts. Our results suggest that the creation of additional minimal genomes could help reveal different gene compositions and strategies that can support life, even within closely related species.
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Affiliation(s)
- Vincent Baby
- Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | | | - Jules Gagnon
- Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | | | - Dominick Matteau
- Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Tom Knight
- Ginkgo Bioworks, Boston, Massachusetts, USA
| | - Sébastien Rodrigue
- Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
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67
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Shaham G, Tuller T. Genome scale analysis of Escherichia coli with a comprehensive prokaryotic sequence-based biophysical model of translation initiation and elongation. DNA Res 2018; 25:195-205. [PMID: 29161365 PMCID: PMC6012489 DOI: 10.1093/dnares/dsx049] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 11/04/2017] [Indexed: 11/17/2022] Open
Abstract
Translation initiation in prokaryotes is affected by the mRNA folding and interaction of the ribosome binding site with the ribosomal RNA. The elongation rate is affected, among other factors, by the local biophysical properties of the coding regions, the decoding rates of different codons, and the interactions among ribosomes. Currently, there is no comprehensive biophysical model of translation that enables the prediction of mRNA translation dynamics based only on the transcript sequence and while considering all of these fundamental aspects of translation. In this study, we provide, for the first time, a computational simulative biophysical model of both translation initiation and elongation with all aspects mentioned above. We demonstrate our model performance and advantages focusing on Escherichia coli genes. We further show that the model enables prediction of translation rate, protein levels, and ribosome densities. In addition, our model enables quantifying the effect of silent mutations on translation rate in different parts of the transcript, the relative effect of mutations on translation initiation and elongation, and the effect of mutations on ribosome traffic jams. Thus, unlike previous models, the proposed one provides comprehensive information, facilitating future research in disciplines such as molecular evolution, synthetic biology, and functional genomics. A toolkit to estimate translation dynamics of transcripts is available at: https://www.cs.tau.ac.il/∼tamirtul/transim.
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Affiliation(s)
- Gilad Shaham
- Department of Biomedical Engineering, The Engineering Faculty, Tel Aviv University, Israel
| | - Tamir Tuller
- Department of Biomedical Engineering, The Engineering Faculty, Tel Aviv University, Israel
- The Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
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68
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Danchin A, Sekowska A, Noria S. Functional Requirements in the Program and the Cell Chassis for Next-Generation Synthetic Biology. Synth Biol (Oxf) 2018. [DOI: 10.1002/9783527688104.ch5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Antoine Danchin
- Institute of Cardiometabolism and Nutrition; 47 boulevard de l'Hôpital Paris 75013 France
| | - Agnieszka Sekowska
- Institute of Cardiometabolism and Nutrition; 47 boulevard de l'Hôpital Paris 75013 France
| | - Stanislas Noria
- Fondation Fourmentin-Guilbert; 2 avenue du Pavé Neuf Noisy le Grand 93160 France
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69
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Wang L, Maranas CD. MinGenome: An In Silico Top-Down Approach for the Synthesis of Minimized Genomes. ACS Synth Biol 2018; 7:462-473. [PMID: 29254336 DOI: 10.1021/acssynbio.7b00296] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Genome minimized strains offer advantages as production chassis by reducing transcriptional cost, eliminating competing functions and limiting unwanted regulatory interactions. Existing approaches for identifying stretches of DNA to remove are largely ad hoc based on information on presumably dispensable regions through experimentally determined nonessential genes and comparative genomics. Here we introduce a versatile genome reduction algorithm MinGenome that implements a mixed-integer linear programming (MILP) algorithm to identify in size descending order all dispensable contiguous sequences without affecting the organism's growth or other desirable traits. Known essential genes or genes that cause significant fitness or performance loss can be flagged and their deletion can be prohibited. MinGenome also preserves needed transcription factors and promoter regions ensuring that retained genes will be properly transcribed while also avoiding the simultaneous deletion of synthetic lethal pairs. The potential benefit of removing even larger contiguous stretches of DNA if only one or two essential genes (to be reinserted elsewhere) are within the deleted sequence is explored. We applied the algorithm to design a minimized E. coli strain and found that we were able to recapitulate the long deletions identified in previous experimental studies and discover alternative combinations of deletions that have not yet been explored in vivo.
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Affiliation(s)
- Lin Wang
- Department of Chemical
Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Costas D. Maranas
- Department of Chemical
Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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70
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Xin Y, Guo T, Mu Y, Kong J. Coupling the recombineering to Cre-lox system enables simplified large-scale genome deletion in Lactobacillus casei. Microb Cell Fact 2018; 17:21. [PMID: 29433512 PMCID: PMC5808424 DOI: 10.1186/s12934-018-0872-4] [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: 10/14/2017] [Accepted: 02/09/2018] [Indexed: 12/22/2022] Open
Abstract
Background Lactobacillus casei is widely used in the dairy and pharmaceutical industries and a promising candidate for use as cell factories. Recently, genome sequencing and functional genomics provide the possibility for reducing L. casei genome. However, it was still limited by the inefficient and laborious genome deletion methods. Results Here, we proposed a genome minimization strategy based on LCABL_13040-50-60 recombineering and Cre-lox site-specific recombination system in L. casei. The LCABL_13040-50-60 recombineering system was used to introduce two lox sites (lox66 and lox71) into 5′ and 3′ ends of the targeted region. Subsequently, the targeted region was excised by Cre recombinase. The robustness of the strategy was demonstrated by single-deletion of a nonessential ~ 39.3 kb or an important ~ 12.8 kb region and simultaneous deletion of two non-continuous genome regions (5.2 and 6.6 kb) with 100% efficiency. Furthermore, a cyclical application of this strategy generated a double-deletion mutant of which 1.68% of the chromosome was sequentially excised. Moreover, biological features (including growth rate, electroporation efficiency, cell morphology or heterologous protein productivity) of these mutants were characterized. Conclusions To our knowledge, this strategy is the first instance of sequential deletion of large-scale genome regions in L. casei. We expected this efficient and inexpensive tool can help for rapid genome streamlining and generation restructured L. casei strains used as cell factories. Electronic supplementary material The online version of this article (10.1186/s12934-018-0872-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yongping Xin
- State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nanlu, Jinan, 250100, People's Republic of China
| | - Tingting Guo
- State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nanlu, Jinan, 250100, People's Republic of China
| | - Yingli Mu
- State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nanlu, Jinan, 250100, People's Republic of China
| | - Jian Kong
- State Key Laboratory of Microbial Technology, Shandong University, 27 Shanda Nanlu, Jinan, 250100, People's Republic of China.
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71
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Fenn K, Strandwitz P, Stewart EJ, Dimise E, Rubin S, Gurubacharya S, Clardy J, Lewis K. Quinones are growth factors for the human gut microbiota. MICROBIOME 2017; 5:161. [PMID: 29262868 PMCID: PMC5738691 DOI: 10.1186/s40168-017-0380-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 12/04/2017] [Indexed: 05/19/2023]
Abstract
BACKGROUND The human gut microbiome has been linked to numerous components of health and disease. However, approximately 25% of the bacterial species in the gut remain uncultured, which limits our ability to properly understand, and exploit, the human microbiome. Previously, we found that growing environmental bacteria in situ in a diffusion chamber enables growth of uncultured species, suggesting the existence of growth factors in the natural environment not found in traditional cultivation media. One source of growth factors proved to be neighboring bacteria, and by using co-culture, we isolated previously uncultured organisms from the marine environment and identified siderophores as a major class of bacterial growth factors. Here, we employ similar co-culture techniques to grow bacteria from the human gut microbiome and identify novel growth factors. RESULTS By testing dependence of slow-growing colonies on faster-growing neighboring bacteria in a co-culture assay, eight taxonomically diverse pairs of bacteria were identified, in which an "induced" isolate formed a gradient of growth around a cultivatable "helper." This set included two novel species Faecalibacterium sp. KLE1255-belonging to the anti-inflammatory Faecalibacterium genus-and Sutterella sp. KLE1607. While multiple helper strains were identified, Escherichia coli was also capable of promoting growth of all induced isolates. Screening a knockout library of E. coli showed that a menaquinone biosynthesis pathway was required for growth induction of Faecalibacterium sp. KLE1255 and other induced isolates. Purified menaquinones induced growth of 7/8 of the isolated strains, quinone specificity profiles for individual bacteria were identified, and genome analysis suggests an incomplete menaquinone biosynthetic capability yet the presence of anaerobic terminal reductases in the induced strains, indicating an ability to respire anaerobically. CONCLUSIONS Our data show that menaquinones are a major class of growth factors for bacteria from the human gut microbiome. These organisms are taxonomically diverse, including members of the genus Faecalibacterium, Bacteroides, Bilophila, Gordonibacter, and Sutterella. This suggests that loss of quinone biosynthesis happened independently in many lineages of the human microbiota. Quinones can be used to improve existing bacterial growth media or modulate the human gut microbiota by encouraging the growth of important symbionts, such as Faecalibacterium species.
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Affiliation(s)
- Kathrin Fenn
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Ave, Boston, MA 02115 USA
- Present address: Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115 USA
| | - Philip Strandwitz
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Ave, Boston, MA 02115 USA
| | - Eric J. Stewart
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Ave, Boston, MA 02115 USA
| | - Eric Dimise
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115 USA
| | - Sarah Rubin
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Ave, Boston, MA 02115 USA
- Present address: Department of Molecular Genetics, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Shreya Gurubacharya
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Ave, Boston, MA 02115 USA
| | - Jon Clardy
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115 USA
| | - Kim Lewis
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, 134 Mugar Hall, 360 Huntington Ave, Boston, MA 02115 USA
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72
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Lee JH, Wendisch VF. Production of amino acids - Genetic and metabolic engineering approaches. BIORESOURCE TECHNOLOGY 2017; 245:1575-1587. [PMID: 28552565 DOI: 10.1016/j.biortech.2017.05.065] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 05/22/2023]
Abstract
The biotechnological production of amino acids occurs at the million-ton scale and annually about 6milliontons of l-glutamate and l-lysine are produced by Escherichia coli and Corynebacterium glutamicum strains. l-glutamate and l-lysine production from starch hydrolysates and molasses is very efficient and access to alternative carbon sources and new products has been enabled by metabolic engineering. This review focusses on genetic and metabolic engineering of amino acid producing strains. In particular, rational approaches involving modulation of transcriptional regulators, regulons, and attenuators will be discussed. To address current limitations of metabolic engineering, this article gives insights on recent systems metabolic engineering approaches based on functional tools and method such as genome reduction, amino acid sensors based on transcriptional regulators and riboswitches, CRISPR interference, small regulatory RNAs, DNA scaffolding, and optogenetic control, and discusses future prospects.
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Affiliation(s)
- Jin-Ho Lee
- Major in Food Science & Biotechnology, School of Food Biotechnology & Nutrition, Kyungsung University, 309, Suyeong-ro, Nam-gu, Busan 48434, Republic of Korea
| | - Volker F Wendisch
- Genetics of Prokaryotes, Faculty of Biology and Center for Biotechnology, Bielefeld University, Bielefeld, Germany.
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73
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Glass JI, Merryman C, Wise KS, Hutchison CA, Smith HO. Minimal Cells-Real and Imagined. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a023861. [PMID: 28348033 DOI: 10.1101/cshperspect.a023861] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A minimal cell is one whose genome only encodes the minimal set of genes necessary for the cell to survive. Scientific reductionism postulates the best way to learn the first principles of cellular biology would be to use a minimal cell in which the functions of all genes and components are understood. The genes in a minimal cell are, by definition, essential. In 2016, synthesis of a genome comprised of only the set of essential and quasi-essential genes encoded by the bacterium Mycoplasma mycoides created a near-minimal bacterial cell. This organism performs the cellular functions common to all organisms. It replicates DNA, transcribes RNA, translates proteins, undergoes cell division, and little else. In this review, we examine this organism and contrast it with other bacteria that have been used as surrogates for a minimal cell.
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Affiliation(s)
- John I Glass
- Synthetic Biology and Bioenergy Group, J. Craig Venter Institute, La Jolla, California 92037
| | - Chuck Merryman
- Synthetic Biology and Bioenergy Group, J. Craig Venter Institute, La Jolla, California 92037
| | - Kim S Wise
- Synthetic Biology and Bioenergy Group, J. Craig Venter Institute, La Jolla, California 92037
| | - Clyde A Hutchison
- Synthetic Biology and Bioenergy Group, J. Craig Venter Institute, La Jolla, California 92037
| | - Hamilton O Smith
- Synthetic Biology and Bioenergy Group, J. Craig Venter Institute, La Jolla, California 92037
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74
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Arakawa K, Tomita M. Selection Effects on the Positioning of Genes and Gene Structures from the Interplay of Replication and Transcription in Bacterial Genomes. Evol Bioinform Online 2017. [DOI: 10.1177/117693430700300005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Bacterial chromosomes are partly shaped by the functional requirements for efficient replication, which lead to strand bias as commonly characterized by the excess of guanines over cytosines in the leading strand. Gene structures are also highly organized within bacterial genomes as a result of such functional constraints, displaying characteristic positioning and structuring along the genome. Here we analyze the gene structures in completely sequenced bacterial chromosomes to observe the positional constraints on gene orientation, length, and codon usage with regard to the positions of replication origin and terminus. Selection on these gene features is different in regions surrounding the terminus of replication from the rest of the genome, but the selection could be either positive or negative depending on the species, and these positional effects are partly attributed to the A-T enrichment near the terminus. Characteristic gene structuring relative to the position of replication origin and terminus is commonly observed among most bacterial species with circular chromosomes, and therefore we argue that the highly organized gene positioning as well as the strand bias should be considered for genomics studies of bacteria.
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Affiliation(s)
- Kazuharu Arakawa
- Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa 252-8520, Japan
| | - Masaru Tomita
- Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa 252-8520, Japan
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75
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Wei Y, Deng P, Mohsin A, Yang Y, Zhou H, Guo M, Fang H. An electroporation-free method based on Red recombineering for markerless deletion and genomic replacement in the Escherichia coli DH1 genome. PLoS One 2017; 12:e0186891. [PMID: 29065183 PMCID: PMC5655456 DOI: 10.1371/journal.pone.0186891] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 10/09/2017] [Indexed: 11/24/2022] Open
Abstract
The λ-Red recombination system is a popular method for gene editing. However, its applications are limited due to restricted electroporation of DNA fragments. Here, we present an electroporation-free λ-Red recombination method in which target DNA fragments are excised by I-CreI endonuclease in vivo from the landing pad plasmid. Subsequently, the I-SceI endonuclease-cutting chromosome and DNA double-strand break repair were required. Markerless deletion and genomic replacement were successfully accomplished by this novel approach. Eight nonessential regions of 2.4–104.4 kb in the Escherichia coli DH1 genome were deleted separately with selection efficiencies of 5.3–100%. Additionally, the recombination efficiencies were 2.5–45%, representing an order of magnitude improvement over the electroporation method. For example, for genomic replacement, lycopene expression flux (3.5 kb) was efficiently and precisely integrated into the chromosome, accompanied by replacement of nonessential regions separately into four differently oriented loci. The lycopene production level varied approximately by 5- and 10-fold, corresponding to the integrated position and expression direction, respectively, in the E. coli chromosome.
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Affiliation(s)
- Yanlong Wei
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Pingping Deng
- Institute of Health Sciences, Anhui University, Economic and Technology Development Zone, Hefei, Anhui, China
| | - Ali Mohsin
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Yan Yang
- Luoyang Vocational & Technical College, Luoyang, Henan, China
- Institute of Biotechnology, Academy of Military Medical Sciences, Beijing, China
| | - Huayan Zhou
- Institute of Biotechnology, Academy of Military Medical Sciences, Beijing, China
| | - Meijin Guo
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- * E-mail: (MG); (HF)
| | - Hongqing Fang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Institute of Health Sciences, Anhui University, Economic and Technology Development Zone, Hefei, Anhui, China
- Institute of Biotechnology, Academy of Military Medical Sciences, Beijing, China
- * E-mail: (MG); (HF)
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76
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Weinert LA, Welch JJ. Why Might Bacterial Pathogens Have Small Genomes? Trends Ecol Evol 2017; 32:936-947. [PMID: 29054300 DOI: 10.1016/j.tree.2017.09.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 09/19/2017] [Accepted: 09/20/2017] [Indexed: 12/31/2022]
Abstract
Bacteria that cause serious disease often have smaller genomes, and fewer genes, than their nonpathogenic, or less pathogenic relatives. Here, we review evidence for the generality of this association, and summarise the various reasons why the association might hold. We focus on the population genetic processes that might lead to reductive genome evolution, and show how several of these could be connected to pathogenicity. We find some evidence for most of the processes having acted in bacterial pathogens, including several different modes of genome reduction acting in the same lineage. We argue that predictable processes of genome evolution might not reflect any common underlying process.
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Affiliation(s)
- Lucy A Weinert
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK.
| | - John J Welch
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
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Shen X, Wang Z, Huang X, Hu H, Wang W, Zhang X. Developing genome-reduced Pseudomonas chlororaphis strains for the production of secondary metabolites. BMC Genomics 2017; 18:715. [PMID: 28893188 PMCID: PMC5594592 DOI: 10.1186/s12864-017-4127-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 09/06/2017] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The current chassis organisms or various types of cell factories have considerable advantages and disadvantages. Therefore, it is necessary to develop various chassis for an efficient production of different bioproducts from renewable resources. In this context, synthetic biology offers unique potentialities to produce value-added products of interests. Microbial genome reduction and modification are important strategies for constructing cellular chassis and cell factories. Many genome-reduced strains from Escherichia coli, Bacillus subtilis, Corynebacterium glutamicum and Streptomyces, have been widely used for the production of amino acids, organic acids, and some enzymes. Some Pseudomonas strains could serve as good candidates for ideal chassis cells since they grow fast and can produce many valuable metabolites with low nutritional requirements and strong environmental adaptability. Pseudomonas chlororaphis GP72 is a non-pathogenic plant growth-promoting rhizobacterium that possesses capacities of tolerating various environmental stresses and synthesizing many kinds of bioactive compounds with high yield. These include phenazine-1-carboxylic acid (PCA) and 2-hydroxyphenazine (2-OH-PHZ), which exhibit strong bacteriostatic and antifungal activity toward some microbial pathogens. RESULTS We depleted 685 kb (10.3% of the genomic sequence) from the chromosome of P. chlororaphis GP72(rpeA-) by a markerless deletion method, which included five secondary metabolic gene clusters and 17 strain-specific regions (525 non-essential genes). Then we characterized the 22 multiple-deletion series (MDS) strains. Growth characteristics, production of phenazines and morphologies were changed greatly in mutants with large-fragment deletions. Some of the genome-reduced P. chlororaphis mutants exhibited more productivity than the parental strain GP72(rpeA-). For example, strain MDS22 had 4.4 times higher production of 2-OH-PHZ (99.1 mg/L) than strain GP72(rpeA-), and the specific 2-OH-PHZ production rate (mmol/g/h) increased 11.5-fold. Also and MDS10 had the highest phenazine production (852.0 mg/L) among all the studied strains with a relatively high specific total phenazine production rate (0.0056 g/g/h). CONCLUSIONS In conclusion, P. chlororaphis strains with reduced genome performed better in production of secondary metabolites than the parent strain. The newly developed mutants can be used for the further genetic manipulation to construct chassis cells with the less complex metabolic network, better regulation and more efficient productivity for diverse biotechnological applications.
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Affiliation(s)
- Xuemei Shen
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai, 200240, People's Republic of China.,Beijing Key Laboratory of Nutrition, Health and Food Safety, Nutrition and Health Research Institute, COFCO Corporation, No.4 Road, Future Science and Technology Park South, Beijing, 102209, People's Republic of China
| | - Zheng Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Xianqing Huang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Hongbo Hu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Wei Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Xuehong Zhang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai, 200240, People's Republic of China.
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78
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Mol M, Kabra R, Singh S. Genome modularity and synthetic biology: Engineering systems. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 132:43-51. [PMID: 28801037 DOI: 10.1016/j.pbiomolbio.2017.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 08/05/2017] [Indexed: 12/15/2022]
Abstract
Whole genome sequencing projects running in various laboratories around the world has generated immense data. A systematic phylogenetic analysis of this data shows that genome complexity goes on decreasing as it evolves, due to its modular nature. This modularity can be harnessed to minimize the genome further to reduce it with the bare minimum essential genes. A reduced modular genome, can fuel progress in the area of synthetic biology by providing a ready to use plug and play chassis. Advances in gene editing technology such as the use of tailor made synthetic transcription factors will further enhance the availability of synthetic devices to be applied in the fields of environment, agriculture and health.
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Affiliation(s)
- Milsee Mol
- National Centre for Cell Science, NCCS Complex, SP Pune University Campus, Pune 411007, India
| | - Ritika Kabra
- National Centre for Cell Science, NCCS Complex, SP Pune University Campus, Pune 411007, India
| | - Shailza Singh
- National Centre for Cell Science, NCCS Complex, SP Pune University Campus, Pune 411007, India.
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79
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Zhu D, Fu Y, Liu F, Xu H, Saris PEJ, Qiao M. Enhanced heterologous protein productivity by genome reduction in Lactococcus lactis NZ9000. Microb Cell Fact 2017; 16:1. [PMID: 28049473 PMCID: PMC5210298 DOI: 10.1186/s12934-016-0616-2] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 12/15/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The implementation of novel chassis organisms to be used as microbial cell factories in industrial applications is an intensive research field. Lactococcus lactis, which is one of the most extensively studied model organisms, exhibits superior ability to be used as engineered host for fermentation of desirable products. However, few studies have reported about genome reduction of L. lactis as a clean background for functional genomic studies and a model chassis for desirable product fermentation. RESULTS Four large nonessential DNA regions accounting for 2.83% in L. lactis NZ9000 (L. lactis 9 k) genome (2,530,294 bp) were deleted using the Cre-loxP deletion system as the first steps toward a minimized genome in this study. The mutants were compared with the parental strain in several physiological traits and evaluated as microbial cell factories for heterologous protein production (intracellular and secretory expression) with the red fluorescent protein (RFP) and the bacteriocin leucocin C (LecC) as reporters. The four mutants grew faster, yielded enhanced biomass, achieved increased adenosine triphosphate content, and diminished maintenance demands compared with the wild strain in the two media tested. In particular, L. lactis 9 k-4 with the largest deletion was identified as the optimum candidate host for recombinant protein production. With nisin induction, not only the transcriptional efficiency but also the production levels of the expressed reporters were approximately three- to fourfold improved compared with the wild strain. The expression of lecC gene controlled with strong constitutive promoters P5 and P8 in L. lactis 9 k-4 was also improved significantly. CONCLUSIONS The genome-streamlined L. lactis 9 k-4 outcompeted the parental strain in several physiological traits assessed. Moreover, L. lactis 9 k-4 exhibited good properties as platform organism for protein production. In future works, the genome of L. lactis will be maximally reduced by using our specific design to provide an even more clean background for functional genomics studies than L. lactis 9 k-4 constructed in this study. Furthermore, an improved background will be potentially available for use in biotechology.
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Affiliation(s)
- Duolong Zhu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China.,Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Yuxin Fu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
| | - Fulu Liu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
| | - Haijin Xu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China
| | - Per Erik Joakim Saris
- Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Mingqiang Qiao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin, China. .,College of Life Sciences, Nankai University, Room 301, Tianjin, China.
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80
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Kamiya K, Takeuchi S. Giant liposome formation toward the synthesis of well-defined artificial cells. J Mater Chem B 2017; 5:5911-5923. [DOI: 10.1039/c7tb01322a] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This review focuses on microfluidic technologies for giant liposome formations which emulate environments of biological cells.
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Affiliation(s)
- Koki Kamiya
- Artificial Cell Membrane Systems Group
- Kanagawa Institute of Industrial Science and Technology
- Kawasaki
- Japan
| | - Shoji Takeuchi
- Artificial Cell Membrane Systems Group
- Kanagawa Institute of Industrial Science and Technology
- Kawasaki
- Japan
- Institute of Industrial Science
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81
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Cohen O, Oberhardt M, Yizhak K, Ruppin E. Essential Genes Embody Increased Mutational Robustness to Compensate for the Lack of Backup Genetic Redundancy. PLoS One 2016; 11:e0168444. [PMID: 27997585 PMCID: PMC5173180 DOI: 10.1371/journal.pone.0168444] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 12/01/2016] [Indexed: 11/23/2022] Open
Abstract
Genetic robustness is a hallmark of cells, occurring through many mechanisms and at many levels. Essential genes lack the common robustness mechanism of genetic redundancy (i.e., existing alongside other genes with the same function), and thus appear at first glance to leave cells highly vulnerable to genetic or environmental perturbations. Here we explore a hypothesis that cells might protect against essential gene loss through mechanisms that occur at various cellular levels aside from the level of the gene. Using Escherichia coli and Saccharomyces cerevisiae as models, we find that essential genes are enriched over non-essential genes for properties we call "coding efficiency" and "coding robustness", denoting respectively a gene's efficiency of translation and robustness to non-synonymous mutations. The coding efficiency levels of essential genes are highly positively correlated with their evolutionary conservation levels, suggesting that this feature plays a key role in protecting conserved, evolutionarily important genes. We then extend our hypothesis into the realm of metabolic networks, showing that essential metabolic reactions are encoded by more "robust" genes than non-essential reactions, and that essential metabolites are produced by more reactions than non-essential metabolites. Taken together, these results testify that robustness at the gene-loss level and at the mutation level (and more generally, at two cellular levels that are usually treated separately) are not decoupled, but rather, that cellular vulnerability exposed due to complete gene loss is compensated by increased mutational robustness. Why some genes are backed up primarily against loss and others against mutations still remains an open question.
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Affiliation(s)
- Osher Cohen
- School of Computer Sciences and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Matthew Oberhardt
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD, United States of America
| | - Keren Yizhak
- School of Computer Sciences and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eytan Ruppin
- School of Computer Sciences and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD, United States of America
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82
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Martínez-García E, de Lorenzo V. The quest for the minimal bacterial genome. Curr Opin Biotechnol 2016; 42:216-224. [DOI: 10.1016/j.copbio.2016.09.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 09/01/2016] [Accepted: 09/02/2016] [Indexed: 01/09/2023]
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83
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Construction of a minimal genome as a chassis for synthetic biology. Essays Biochem 2016; 60:337-346. [DOI: 10.1042/ebc20160024] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 09/26/2016] [Accepted: 09/29/2016] [Indexed: 12/15/2022]
Abstract
Microbial diversity and complexity pose challenges in understanding the voluminous genetic information produced from whole-genome sequences, bioinformatics and high-throughput ‘-omics’ research. These challenges can be overcome by a core blueprint of a genome drawn with a minimal gene set, which is essential for life. Systems biology and large-scale gene inactivation studies have estimated the number of essential genes to be ∼300–500 in many microbial genomes. On the basis of the essential gene set information, minimal-genome strains have been generated using sophisticated genome engineering techniques, such as genome reduction and chemical genome synthesis. Current size-reduced genomes are not perfect minimal genomes, but chemically synthesized genomes have just been constructed. Some minimal genomes provide various desirable functions for bioindustry, such as improved genome stability, increased transformation efficacy and improved production of biomaterials. The minimal genome as a chassis genome for synthetic biology can be used to construct custom-designed genomes for various practical and industrial applications.
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84
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Ellis M, Patel P, Edon M, Ramage W, Dickinson R, Humphreys DP. Development of a high yieldingE. coliperiplasmic expression system for the production of humanized Fab' fragments. Biotechnol Prog 2016; 33:212-220. [DOI: 10.1002/btpr.2393] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 10/19/2016] [Indexed: 02/01/2023]
Affiliation(s)
- Mark Ellis
- Discovery Research, Protein Sciences; UCB Pharma, 208 Bath Road; Slough, Berkshire SL1 3WE U.K
| | | | - Marjory Edon
- Novasep, 5 chemin du Pilon, St Maurice de Beynost; Miribel 01708 France
| | - Walter Ramage
- NIBSC, Blanche Lane, South Mimms, Potters Bar; Hertfordshire EN6 3QG U.K
| | | | - David P. Humphreys
- Discovery Research, Protein Sciences; UCB Pharma, 208 Bath Road; Slough, Berkshire SL1 3WE U.K
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85
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Tan L, Moriel DG, Totsika M, Beatson SA, Schembri MA. Differential Regulation of the Surface-Exposed and Secreted SslE Lipoprotein in Extraintestinal Pathogenic Escherichia coli. PLoS One 2016; 11:e0162391. [PMID: 27598999 PMCID: PMC5012682 DOI: 10.1371/journal.pone.0162391] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 08/22/2016] [Indexed: 11/19/2022] Open
Abstract
Extra-intestinal pathogenic Escherichia coli (ExPEC) are responsible for diverse infections including meningitis, sepsis and urinary tract infections. The alarming rise in anti-microbial resistance amongst ExPEC complicates treatment and has highlighted the need for alternative preventive measures. SslE is a lipoprotein secreted by a dedicated type II secretion system in E. coli that was first identified as a potential vaccine candidate using reverse genetics. Although the function and protective efficacy of SslE has been studied, the molecular mechanisms that regulate SslE expression remain to be fully elucidated. Here, we show that while the expression of SslE can be detected in E. coli culture supernatants, different strains express and secrete different amounts of SslE when grown under the same conditions. While the histone-like transcriptional regulator H-NS strongly represses sslE at ambient temperatures, the variation in SslE expression at human physiological temperature suggested a more complex mode of regulation. Using a genetic screen to identify novel regulators of sslE in the high SslE-expressing strain UTI89, we defined a new role for the nucleoid-associated regulator Fis and the ribosome-binding GTPase TypA as positive regulators of sslE transcription. We also showed that Fis-mediated enhancement of sslE transcription is dependent on a putative Fis-binding sequence located upstream of the -35 sequence in the core promoter element, and provide evidence to suggest that Fis may work in complex with H-NS to control SslE expression. Overall, this study has defined a new mechanism for sslE regulation and increases our understanding of this broadly conserved E. coli vaccine antigen.
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Affiliation(s)
- Lendl Tan
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, QLD 4072, Brisbane, Australia
| | - Danilo G. Moriel
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, QLD 4072, Brisbane, Australia
| | - Makrina Totsika
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology, QLD 4059, Brisbane, Australia
| | - Scott A. Beatson
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, QLD 4072, Brisbane, Australia
| | - Mark A. Schembri
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, QLD 4072, Brisbane, Australia
- * E-mail:
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86
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Emergent rules for codon choice elucidated by editing rare arginine codons in Escherichia coli. Proc Natl Acad Sci U S A 2016; 113:E5588-97. [PMID: 27601680 DOI: 10.1073/pnas.1605856113] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The degeneracy of the genetic code allows nucleic acids to encode amino acid identity as well as noncoding information for gene regulation and genome maintenance. The rare arginine codons AGA and AGG (AGR) present a case study in codon choice, with AGRs encoding important transcriptional and translational properties distinct from the other synonymous alternatives (CGN). We created a strain of Escherichia coli with all 123 instances of AGR codons removed from all essential genes. We readily replaced 110 AGR codons with the synonymous CGU codons, but the remaining 13 "recalcitrant" AGRs required diversification to identify viable alternatives. Successful replacement codons tended to conserve local ribosomal binding site-like motifs and local mRNA secondary structure, sometimes at the expense of amino acid identity. Based on these observations, we empirically defined metrics for a multidimensional "safe replacement zone" (SRZ) within which alternative codons are more likely to be viable. To evaluate synonymous and nonsynonymous alternatives to essential AGRs further, we implemented a CRISPR/Cas9-based method to deplete a diversified population of a wild-type allele, allowing us to evaluate exhaustively the fitness impact of all 64 codon alternatives. Using this method, we confirmed the relevance of the SRZ by tracking codon fitness over time in 14 different genes, finding that codons that fall outside the SRZ are rapidly depleted from a growing population. Our unbiased and systematic strategy for identifying unpredicted design flaws in synthetic genomes and for elucidating rules governing codon choice will be crucial for designing genomes exhibiting radically altered genetic codes.
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87
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Zhou J, Wu R, Xue X, Qin Z. CasHRA (Cas9-facilitated Homologous Recombination Assembly) method of constructing megabase-sized DNA. Nucleic Acids Res 2016; 44:e124. [PMID: 27220470 PMCID: PMC5001600 DOI: 10.1093/nar/gkw475] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 04/22/2016] [Accepted: 05/11/2016] [Indexed: 01/01/2023] Open
Abstract
Current DNA assembly methods for preparing highly purified linear subassemblies require complex and time-consuming in vitro manipulations that hinder their ability to construct megabase-sized DNAs (e.g. synthetic genomes). We have developed a new method designated 'CasHRA (Cas9-facilitated Homologous Recombination Assembly)' that directly uses large circular DNAs in a one-step in vivo assembly process. The large circular DNAs are co-introduced into Saccharomyces cerevisiae by protoplast fusion, and they are cleaved by RNA-guided Cas9 nuclease to release the linear DNA segments for subsequent assembly by the endogenous homologous recombination system. The CasHRA method allows efficient assembly of multiple large DNA segments in vivo; thus, this approach should be useful in the last stage of genome construction. As a proof of concept, we combined CasHRA with an upstream assembly method (Gibson procedure of genome assembly) and successfully constructed a 1.03 Mb MGE-syn1.0 (Minimal Genome of Escherichia coli) that contained 449 essential genes and 267 important growth genes. We expect that CasHRA will be widely used in megabase-sized genome constructions.
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Affiliation(s)
- Jianting Zhou
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Ronghai Wu
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoli Xue
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Zhongjun Qin
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
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88
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Kurokawa M, Seno S, Matsuda H, Ying BW. Correlation between genome reduction and bacterial growth. DNA Res 2016; 23:517-525. [PMID: 27374613 PMCID: PMC5144675 DOI: 10.1093/dnares/dsw035] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 06/08/2016] [Indexed: 11/13/2022] Open
Abstract
Genome reduction by removing dispensable genomic sequences in bacteria is commonly used in both fundamental and applied studies to determine the minimal genetic requirements for a living system or to develop highly efficient bioreactors. Nevertheless, whether and how the accumulative loss of dispensable genomic sequences disturbs bacterial growth remains unclear. To investigate the relationship between genome reduction and growth, a series of Escherichia coli strains carrying genomes reduced in a stepwise manner were used. Intensive growth analyses revealed that the accumulation of multiple genomic deletions caused decreases in the exponential growth rate and the saturated cell density in a deletion-length-dependent manner as well as gradual changes in the patterns of growth dynamics, regardless of the growth media. Accordingly, a perspective growth model linking genome evolution to genome engineering was proposed. This study provides the first demonstration of a quantitative connection between genomic sequence and bacterial growth, indicating that growth rate is potentially associated with dispensable genomic sequences.
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Affiliation(s)
- Masaomi Kurokawa
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan
| | - Shigeto Seno
- Graduate School of Information Science and Technology, Osaka University, Osaka 565-0871, Japan
| | - Hideo Matsuda
- Graduate School of Information Science and Technology, Osaka University, Osaka 565-0871, Japan
| | - Bei-Wen Ying
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan
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89
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Updates on industrial production of amino acids using Corynebacterium glutamicum. World J Microbiol Biotechnol 2016; 32:105. [DOI: 10.1007/s11274-016-2060-1] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 03/27/2016] [Indexed: 12/14/2022]
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90
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Liu Y, Yang M, Chen J, Yan D, Cheng W, Wang Y, Thygesen A, Chen R, Xing J, Wang Q, Ma Y. PCR-Based Seamless Genome Editing with High Efficiency and Fidelity in Escherichia coli. PLoS One 2016; 11:e0149762. [PMID: 27019283 PMCID: PMC4809717 DOI: 10.1371/journal.pone.0149762] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 02/04/2016] [Indexed: 11/18/2022] Open
Abstract
Efficiency and fidelity are the key obstacles for genome editing toolboxes. In the present study, a PCR-based tandem repeat assisted genome editing (TRAGE) method with high efficiency and fidelity was developed. The design of TRAGE is based on the mechanism of repair of spontaneous double-strand breakage (DSB) via replication fork reactivation. First, cat-sacB cassette flanked by tandem repeat sequence was integrated into target site in chromosome assisted by Red enzymes. Then, for the excision of the cat-sacB cassette, only subculturing is needed. The developed method was successfully applied for seamlessly deleting, substituting and inserting targeted genes using PCR products. The effects of different manipulations including sucrose addition time, subculture times in LB with sucrose and stages of inoculation on the efficiency were investigated. With our recommended procedure, seamless excision of cat-sacB cassette can be realized in 48 h efficiently. We believe that the developed method has great potential for seamless genome editing in E. coli.
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Affiliation(s)
- Yilan Liu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 XiQiDao, Tianjin Airport Economic Area, Tianjin, 300308, China
| | - Maohua Yang
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Jinjin Chen
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Daojiang Yan
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Wanwan Cheng
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Yanyan Wang
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Anders Thygesen
- Center of Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, DK-2800, Lyngby, Denmark
| | - Ruonan Chen
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Jianmin Xing
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
- * E-mail: (JX); (QW)
| | - Qinhong Wang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 XiQiDao, Tianjin Airport Economic Area, Tianjin, 300308, China
- * E-mail: (JX); (QW)
| | - Yanhe Ma
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 XiQiDao, Tianjin Airport Economic Area, Tianjin, 300308, China
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91
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Karcagi I, Draskovits G, Umenhoffer K, Fekete G, Kovács K, Méhi O, Balikó G, Szappanos B, Györfy Z, Fehér T, Bogos B, Blattner FR, Pál C, Pósfai G, Papp B. Indispensability of Horizontally Transferred Genes and Its Impact on Bacterial Genome Streamlining. Mol Biol Evol 2016; 33:1257-69. [PMID: 26769030 DOI: 10.1093/molbev/msw009] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Why are certain bacterial genomes so small and compact? The adaptive genome streamlining hypothesis posits that selection acts to reduce genome size because of the metabolic burden of replicating DNA. To reveal the impact of genome streamlining on cellular traits, we reduced the Escherichia coli genome by up to 20% by deleting regions which have been repeatedly subjects of horizontal transfer in nature. Unexpectedly, horizontally transferred genes not only confer utilization of specific nutrients and elevate tolerance to stresses, but also allow efficient usage of resources to build new cells, and hence influence fitness in routine and stressful environments alike. Genome reduction affected fitness not only by gene loss, but also by induction of a general stress response. Finally, we failed to find evidence that the advantage of smaller genomes would be due to a reduced metabolic burden of replicating DNA or a link with smaller cell size. We conclude that as the potential energetic benefit gained by deletion of short genomic segments is vanishingly small compared with the deleterious side effects of these deletions, selection for reduced DNA synthesis costs is unlikely to shape the evolution of small genomes.
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Affiliation(s)
- Ildikó Karcagi
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Gábor Draskovits
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Kinga Umenhoffer
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Gergely Fekete
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Károly Kovács
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Orsolya Méhi
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Gabriella Balikó
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Balázs Szappanos
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Zsuzsanna Györfy
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Tamás Fehér
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Balázs Bogos
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | | | - Csaba Pál
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - György Pósfai
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Balázs Papp
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
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92
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Watanabe K, Tominaga K, Kitamura M, Kato JI. Systematic identification of synthetic lethal mutations with reduced-genome Escherichia coli: synthetic genetic interactions among yoaA, xthA and holC related to survival from MMS exposure. Genes Genet Syst 2016; 91:183-188. [DOI: 10.1266/ggs.15-00068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Keisuke Watanabe
- Department of Biological Sciences, Graduate Schools of Science and Engineering, Tokyo Metropolitan University
| | - Kento Tominaga
- Department of Biological Sciences, Graduate Schools of Science and Engineering, Tokyo Metropolitan University
| | - Maiko Kitamura
- Department of Biological Sciences, Graduate Schools of Science and Engineering, Tokyo Metropolitan University
| | - Jun-ichi Kato
- Department of Biological Sciences, Graduate Schools of Science and Engineering, Tokyo Metropolitan University
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93
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Tsukuda M, Nakashima N, Miyazaki K. Counterselection method based on conditional silencing of antitoxin genes in Escherichia coli. J Biosci Bioeng 2015; 120:591-5. [DOI: 10.1016/j.jbiosc.2015.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 03/02/2015] [Accepted: 03/12/2015] [Indexed: 01/29/2023]
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94
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Yama K, Matsumoto Y, Murakami Y, Seno S, Matsuda H, Gotoh K, Motooka D, Nakamura S, Ying BW, Yomo T. Functional specialization in regulation and quality control in thermal adaptive evolution. Genes Cells 2015; 20:943-55. [PMID: 26373241 DOI: 10.1111/gtc.12298] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Accepted: 08/04/2015] [Indexed: 01/22/2023]
Abstract
Distinctive survival strategies, specialized in regulation and in quality control, were observed in thermal adaptive evolution with a laboratory Escherichia coli strain. The two specialists carried a single mutation either within rpoH or upstream of groESL, which led to the activated global regulation by sigma factor 32 or an increased amount of GroEL/ES chaperonins, respectively. Although both specialists succeeded in thermal adaptation, the common winner of the evolution was the specialist in quality control, that is, the strategy of chaperonin-mediated protein folding. To understand this evolutionary consequence, multilevel analyses of cellular status, for example, transcriptome, protein and growth fitness, were carried out. The specialist in quality control showed less change in transcriptional reorganization responding to temperature increase, which was consistent with the finding of that the two specialists showed the biased expression of molecular chaperones. Such repressed changes in gene expression seemed to be advantageous for long-term sustainability because a specific increase in chaperonins not only facilitated the folding of essential gene products but also saved cost in gene expression compared with the overall transcriptional increase induced by rpoH regulation. Functional specialization offered two strategies for successful thermal adaptation, whereas the evolutionary advantageous was more at the points of cost-saving in gene expression and the essentiality in protein folding.
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Affiliation(s)
- Kazuma Yama
- Graduate School of Information Science and Technology, Osaka University, Osaka, 565-0871, Japan
| | - Yuki Matsumoto
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, 305-8572, Japan
| | - Yoshie Murakami
- Graduate School of Information Science and Technology, Osaka University, Osaka, 565-0871, Japan
| | - Shigeto Seno
- Graduate School of Information Science and Technology, Osaka University, Osaka, 565-0871, Japan
| | - Hideo Matsuda
- Graduate School of Information Science and Technology, Osaka University, Osaka, 565-0871, Japan
| | - Kazuyoshi Gotoh
- Research Institute for Microbial Diseases, Osaka University, Osaka, 565-0871, Japan
| | - Daisuke Motooka
- Research Institute for Microbial Diseases, Osaka University, Osaka, 565-0871, Japan
| | - Shota Nakamura
- Research Institute for Microbial Diseases, Osaka University, Osaka, 565-0871, Japan
| | - Bei-Wen Ying
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki, 305-8572, Japan
| | - Tetsuya Yomo
- Graduate School of Information Science and Technology, Osaka University, Osaka, 565-0871, Japan.,Graduate School of Frontier Biosciences, Osaka University, Osaka, 565-0871, Japan.,Exploratory Research for Advanced Technology, Japan Science and Technology Agency, Tokyo, 102-0076, Japan
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95
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Choe D, Cho S, Kim SC, Cho BK. Minimal genome: Worthwhile or worthless efforts toward being smaller? Biotechnol J 2015; 11:199-211. [DOI: 10.1002/biot.201400838] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/08/2015] [Accepted: 07/27/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Donghui Choe
- Department of Biological Sciences; Korea Advanced Institute of Science and Technology (KAIST); Daejeon Republic of Korea
| | - Suhyung Cho
- Department of Biological Sciences; Korea Advanced Institute of Science and Technology (KAIST); Daejeon Republic of Korea
| | - Sun Chang Kim
- Department of Biological Sciences; Korea Advanced Institute of Science and Technology (KAIST); Daejeon Republic of Korea
- Intelligent Synthetic Biology Center; Daejeon Republic of Korea
| | - Byung-Kwan Cho
- Department of Biological Sciences; Korea Advanced Institute of Science and Technology (KAIST); Daejeon Republic of Korea
- Intelligent Synthetic Biology Center; Daejeon Republic of Korea
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96
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Heider SAE, Wendisch VF. Engineering microbial cell factories: Metabolic engineering ofCorynebacterium glutamicumwith a focus on non-natural products. Biotechnol J 2015. [DOI: 10.1002/biot.201400590] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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97
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Xue X, Wang T, Jiang P, Shao Y, Zhou M, Zhong L, Wu R, Zhou J, Xia H, Zhao G, Qin Z. MEGA (Multiple Essential Genes Assembling) deletion and replacement method for genome reduction in Escherichia coli. ACS Synth Biol 2015; 4:700-6. [PMID: 25494410 DOI: 10.1021/sb500324p] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Top-down reduction of the bacterial genome to construct desired chassis cells is important for synthetic biology. However, the current progress in the field of genome reduction is greatly hindered by indispensable life-essential genes that are interspersed throughout the chromosomal loci. Here, we described a new method designated as "MEGA (Multiple Essential Genes Assembling) deletion and replacement" that functions by assembling multiple essential genes in an E. coli-S. cerevisiae shuttle vector, removing targeted chromosomal regions containing essential and nonessential genes using a one-round deletion, and then integrating the cloned essential genes into the in situ chromosomal loci via I-SceI endonuclease cleavage. As a proof of concept, we separately generated three large deletions (80-205 kbp) in the E. coli MDS42 chromosome. We believe that the MEGA deletion and replacement method has potential to become widely used in large-scale genome reductions in other sequenced organisms in addition to E. coli.
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Affiliation(s)
- Xiaoli Xue
- Key Laboratory of Synthetic
Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Tao Wang
- Key Laboratory of Synthetic
Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Peng Jiang
- Key Laboratory of Synthetic
Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yangyang Shao
- Key Laboratory of Synthetic
Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Min Zhou
- Key Laboratory of Synthetic
Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Li Zhong
- Key Laboratory of Synthetic
Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Ronghai Wu
- Key Laboratory of Synthetic
Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jianting Zhou
- Key Laboratory of Synthetic
Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Haiyang Xia
- Key Laboratory of Synthetic
Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Guoping Zhao
- Key Laboratory of Synthetic
Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Zhongjun Qin
- Key Laboratory of Synthetic
Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
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98
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Lu Y, Lu Y, Deng J, Peng H, Lu H, Lu LJ. A novel essential domain perspective for exploring gene essentiality. Bioinformatics 2015; 31:2921-9. [PMID: 26002906 DOI: 10.1093/bioinformatics/btv312] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 05/13/2015] [Indexed: 02/05/2023] Open
Abstract
MOTIVATION Genes with indispensable functions are identified as essential; however, the traditional gene-level studies of essentiality have several limitations. In this study, we characterized gene essentiality from a new perspective of protein domains, the independent structural or functional units of a polypeptide chain. RESULTS To identify such essential domains, we have developed an Expectation-Maximization (EM) algorithm-based Essential Domain Prediction (EDP) Model. With simulated datasets, the model provided convergent results given different initial values and offered accurate predictions even with noise. We then applied the EDP model to six microbial species and predicted 1879 domains to be essential in at least one species, ranging 10-23% in each species. The predicted essential domains were more conserved than either non-essential domains or essential genes. Comparing essential domains in prokaryotes and eukaryotes revealed an evolutionary distance consistent with that inferred from ribosomal RNA. When utilizing these essential domains to reproduce the annotation of essential genes, we received accurate results that suggest protein domains are more basic units for the essentiality of genes. Furthermore, we presented several examples to illustrate how the combination of essential and non-essential domains can lead to genes with divergent essentiality. In summary, we have described the first systematic analysis on gene essentiality on the level of domains. CONTACT huilu.bioinfo@gmail.com or Long.Lu@cchmc.org SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Yao Lu
- Shanghai Institute of Medical Genetics, Shanghai Children's Hospital, Shanghai Jiao Tong University, 24/1400 Beijing (W) Road, Shanghai 200040, People's Republic of China
| | - Yulan Lu
- State Key Laboratory of Genetic Engineering Institute of Biostatistics, School of Life Science, Fudan University, Shanghai 200433, People's Republic of China
| | - Jingyuan Deng
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Hai Peng
- Institute for Systems Biology, Jianghan University, Wuhan, Hubei, People's Republic of China
| | - Hui Lu
- Shanghai Institute of Medical Genetics, Shanghai Children's Hospital, Shanghai Jiao Tong University, 24/1400 Beijing (W) Road, Shanghai 200040, People's Republic of China, Department of Bioengineering (MC 063), University of Illinois at Chicago, Chicago, IL 60607-7052, USA and Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Long Jason Lu
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA, Institute for Systems Biology, Jianghan University, Wuhan, Hubei, People's Republic of China
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99
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Hierarchical organization of fluxes in Escherichia coli metabolic network: Using flux coupling analysis for understanding the physiological properties of metabolic genes. Gene 2015; 561:199-208. [DOI: 10.1016/j.gene.2015.02.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 02/04/2015] [Accepted: 02/12/2015] [Indexed: 01/09/2023]
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100
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Abstract
The concept of the minimal cell has fascinated scientists for a long time, from both fundamental and applied points of view. This broad concept encompasses extreme reductions of genomes, the last universal common ancestor (LUCA), the creation of semiartificial cells, and the design of protocells and chassis cells. Here we review these different areas of research and identify common and complementary aspects of each one. We focus on systems biology, a discipline that is greatly facilitating the classical top-down and bottom-up approaches toward minimal cells. In addition, we also review the so-called middle-out approach and its contributions to the field with mathematical and computational models. Owing to the advances in genomics technologies, much of the work in this area has been centered on minimal genomes, or rather minimal gene sets, required to sustain life. Nevertheless, a fundamental expansion has been taking place in the last few years wherein the minimal gene set is viewed as a backbone of a more complex system. Complementing genomics, progress is being made in understanding the system-wide properties at the levels of the transcriptome, proteome, and metabolome. Network modeling approaches are enabling the integration of these different omics data sets toward an understanding of the complex molecular pathways connecting genotype to phenotype. We review key concepts central to the mapping and modeling of this complexity, which is at the heart of research on minimal cells. Finally, we discuss the distinction between minimizing the number of cellular components and minimizing cellular complexity, toward an improved understanding and utilization of minimal and simpler cells.
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