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Baruah N, Haajanen R, Rahman MT, Pirttilä AM, Koskimäki JJ. Biosynthesis of polyhydroxybutyrate by Methylorubrum extorquens DSM13060 is essential for intracellular colonization in plant endosymbiosis. FRONTIERS IN PLANT SCIENCE 2024; 15:1302705. [PMID: 38390299 PMCID: PMC10883064 DOI: 10.3389/fpls.2024.1302705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 01/15/2024] [Indexed: 02/24/2024]
Abstract
Methylorubrum extorquens DSM13060 is an endosymbiont that lives in the cells of shoot tip meristems. The bacterium is methylotrophic and consumes plant-derived methanol for the production of polyhydroxybutyrate (PHB). The PHB provides protection against oxidative stress for both host and endosymbiont cells through its fragments, methyl-esterified 3-hydroxybutyrate (ME-3HB) oligomers. We evaluated the role of the genes involved in the production of ME-3HB oligomers in the host colonization by the endosymbiont M. extorquens DSM13060 through targeted genetic mutations. The strains with deletions in PHB synthase (phaC), PHB depolymerase (phaZ1), and a transcription factor (phaR) showed altered PHB granule characteristics, as ΔphaC had a significantly low number of granules, ΔphaR had a significantly increased number of granules, and ΔphaZ1 had significantly large PHB granules in the bacterial cells. When the deletion strains were exposed to oxidative stress, the ΔphaC strain was sensitive to 10 mM HO· and 20 mM H2O2. The colonization of the host, Scots pine (Pinus sylvestris L.), by the deletion strains varied greatly. The deletion strain ΔphaR colonized the host mainly intercellularly, whereas the ΔphaZ1 strain was a slightly poorer colonizer than the control. The deletion strain ΔphaC lacked the colonization potential, living mainly on the surfaces of the epidermis of pine roots and shoots in contrast to the control, which intracellularly colonized all pine tissues within the study period. In earlier studies, deletions within the PHB metabolic pathway have had a minor effect on plant colonization by rhizobia. We have previously shown the association between ME-3HB oligomers, produced by PhaC and PhaZ1, and the ability to alleviate host-generated oxidative stress during plant infection by the endosymbiont M. extorquens DSM13060. Our current results show that the low capacity for PHB synthesis leads to poor tolerance of oxidative stress and loss of colonization potential by the endosymbiont. Altogether, our findings demonstrate that the metabolism of PHB in M. extorquens DSM13060 is an important trait in the non-rhizobial endosymbiosis.
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Affiliation(s)
- Namrata Baruah
- Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
| | - Roosa Haajanen
- Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
| | - Mohammad Tanvir Rahman
- Disease Networks, Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | | | - Janne J Koskimäki
- Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
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Zhu L, Song Y, Ma S, Yang S. Heterologous production of 3-hydroxypropionic acid in Methylorubrum extorquens by introducing the mcr gene via a multi-round chromosomal integration system based on cre-lox71/lox66 and transposon. Microb Cell Fact 2024; 23:5. [PMID: 38172868 PMCID: PMC10763676 DOI: 10.1186/s12934-023-02275-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 12/14/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND AND AIM Reprogramming microorganisms to enhance the production of metabolites is a part of contemporary synthetic biology, which relies on the availability of genetic tools to successfully manipulate the bacteria. Methylorubrum extorquens AM1 is a platform microorganism used to convert C1 compounds into various value-added products. However, the repertoire of available plasmids to conveniently and quickly fine-tune the expression of multiple genes in this strain is extremely limited compared with other model microorganisms such as Escherichia coli. Thus, this study aimed to integrate existing technologies, such as transposon-mediated chromosomal integration and cre-lox-mediated recombination, to achieve the diversified expression of target genes through multiple chromosomal insertions in M. extorquens AM1. RESULTS A single plasmid toolkit, pSL-TP-cre-km, containing a miniHimar1 transposon and an inducible cre-lox71/lox66 system, was constructed and characterized for its multiple chromosomal integration capacity. A co-transcribed mcr-egfp cassette [for the production of 3-hydroxypropionic acid (3-HP) and a reporting green fluorescent protein] was added to construct pTP-cre-mcr-egfp for evaluating its utility in mediating the expression of heterologous genes, resulting in the production of 3-HP with a titer of 34.7-55.2 mg/L by two chromosomal integration copies. Furthermore, in association with the expression of plasmid-based mcr, 3-HP production increased to 65.5-92.4 mg/L. CONCLUSIONS This study used a multi-round chromosomal integration system based on cre-lox71/lox66 and a transposon to construct a single constructed vector. A heterologous mcr gene was introduced through this vector, and high expression of 3-hydroxypropionic acid was achieved in M. extorquens. This study provided an efficient genetic tool for manipulating M. extorquens, which not only help increase the expression of heterologous genes in M. extorquens but also provide a reference for strains lacking genetic manipulation vectors.
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Affiliation(s)
- Liping Zhu
- Shandong Province Key Laboratory of Applied Mycology, Qingdao International Center on Microbes Utilizing Biogas, School of Life Sciences, Qingdao Agricultural University, Qingdao, Shandong Province, People's Republic of China.
| | - Yazhen Song
- Shandong Province Key Laboratory of Applied Mycology, Qingdao International Center on Microbes Utilizing Biogas, School of Life Sciences, Qingdao Agricultural University, Qingdao, Shandong Province, People's Republic of China
| | - Shunan Ma
- Shandong Province Key Laboratory of Applied Mycology, Qingdao International Center on Microbes Utilizing Biogas, School of Life Sciences, Qingdao Agricultural University, Qingdao, Shandong Province, People's Republic of China
| | - Song Yang
- Shandong Province Key Laboratory of Applied Mycology, Qingdao International Center on Microbes Utilizing Biogas, School of Life Sciences, Qingdao Agricultural University, Qingdao, Shandong Province, People's Republic of China.
- Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, People's Republic of China.
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Sathesh-Prabu C, Ryu YS, Lee SK. Levulinic Acid-Inducible and Tunable Gene Expression System for Methylorubrum extorquens. Front Bioeng Biotechnol 2022; 9:797020. [PMID: 34976985 PMCID: PMC8714952 DOI: 10.3389/fbioe.2021.797020] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 11/17/2021] [Indexed: 11/13/2022] Open
Abstract
Methylorubrum extorquens AM1 is an efficient platform strain possessing biotechnological potential in formate- and methanol-based single carbon (C1) bioeconomy. Constitutive expression or costly chemical-inducible expression systems are not always desirable. Here, several glucose-, xylose-, and levulinic acid (LA)-inducible promoter systems were assessed for the induction of green fluorescent protein (GFP) as a reporter protein. Among them, the LA-inducible gene expression system (HpdR/P hpdH ) showed a strong expression of GFP (51-fold) compared to the control. The system was induced even at a low concentration of LA (0.1 mM). The fluorescence intensity increased with increasing concentrations of LA up to 20 mM. The system was tunable and tightly controlled with meager basal expression. The maximum GFP yield obtained using the system was 42 mg/g biomass, representing 10% of the total protein content. The efficiency of the proposed system was nearly equivalent (90%-100%) to that of the widely used strong promoters such as P mxaF and P L/O4 . The HpdR/P hpdH system worked equally efficiently in five different strains of M. extorquens. LA is a low-cost, renewable, and sustainable platform chemical that can be used to generate a wide range of products. Hence, the reported system in potent strains of M. extorquens is highly beneficial in the C1-biorefinery industry to produce value-added products and bulk chemicals.
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Affiliation(s)
- Chandran Sathesh-Prabu
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
| | - Young Shin Ryu
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
| | - Sung Kuk Lee
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea.,Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
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Wang ZK, Gong JS, Qin J, Li H, Lu ZM, Shi JS, Xu ZH. Improving the Intensity of Integrated Expression for Microbial Production. ACS Synth Biol 2021; 10:2796-2807. [PMID: 34738786 DOI: 10.1021/acssynbio.1c00334] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Chromosomal integration of exogenous genes is preferred for industrially related fermentation, as plasmid-mediated fermentation leads to extra metabolic burden and genetic instability. Moreover, with the development and advancement of genome engineering and gene editing technologies, inserting genes into chromosomes has become more convenient; integration expression is extensively utilized in microorganisms for industrial bioproduction and expected to become the trend of recombinant protein expression. However, in actual research and application, it is important to enhance the expression of heterologous genes at the host genome level. Herein, we summarized the basic principles and characteristics of genomic integration; furthermore, we highlighted strategies to improve the expression of chromosomal integration of genes and pathways in host strains from three aspects, including chassis cell optimization, regulation of expression elements in gene expression cassettes, optimization of gene dose level and integration sites on chromosomes. Moreover, we reviewed and summarized the relevant studies on the application of integrated expression in the exploration of gene function and the various types of industrial microorganism production. Consequently, this review would serve as a reference for the better application of integrated expression.
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Affiliation(s)
- Zi-Kai Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, PR China
- National Engineering Laboratory for Cereal Fermentation Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China
- Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi 214122, PR China
| | - Jin-Song Gong
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, PR China
| | - Jiufu Qin
- Science Center for Future Foods, Jiangnan University, Wuxi 214122, PR China
| | - Hui Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, PR China
| | - Zhen-Ming Lu
- National Engineering Laboratory for Cereal Fermentation Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China
| | - Jin-Song Shi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Pharmaceutical Sciences, Jiangnan University, Wuxi 214122, PR China
| | - Zheng-Hong Xu
- National Engineering Laboratory for Cereal Fermentation Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, PR China
- Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi 214122, PR China
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Zabalza-Baranguá A, San-Román B, Chacón-Díaz C, de Miguel MJ, Muñoz PM, Iriarte M, Blasco JM, Grilló MJ. GFP tagging of Brucella melitensis Rev1 allows the identification of vaccinated sheep. Transbound Emerg Dis 2018; 66:505-516. [PMID: 30375177 PMCID: PMC7379934 DOI: 10.1111/tbed.13053] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 10/17/2018] [Accepted: 10/22/2018] [Indexed: 11/30/2022]
Abstract
Brucellosis is a worldwide zoonosis causing important economic loss and a public health problem. Small ruminants are the preferred hosts of Brucella melitensis and thus the main source of human infections. Effective control of sheep and goat brucellosis has been achieved in several countries through vaccination with the live-attenuated B. melitensis Rev1 vaccine. However, Rev1 induces a long-lasting serological response that hinders the differentiation between infected and vaccinated animals. A Rev1::gfp strain expressing constitutively the Green Fluorescent Protein (GFP) was built by stable insertion of a mini-Tn7-gfp in the glmS-recG non-codifying chromosomal region. An associated indirect ELISA-GFP was developed to identify anti-GFP antibodies in vaccinated animals. The resulting Rev1::gfp kept the biological properties of the Rev1 reference strain, including residual virulence and efficacy in mice, and was readily distinguished from Rev1 and other Brucella field strains by direct visualization under ultraviolet illumination, fluorescence microscopy and a multiplex PCR-GFP. The Rev1::gfp strain did not elicit anti-GFP antibodies itself in lambs but when applied in combination with recombinant GFP induced an intense and long-lasting (>9 months) anti-GFP serological response readily detectable by the ELISA-GFP. Overall, our results confirm that Rev1 GFP-tagging can be a suitable alternative for identifying vaccinated sheep in infected contexts.
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Affiliation(s)
- Ana Zabalza-Baranguá
- Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Mutilva, Navarra, Spain
| | - Beatriz San-Román
- Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Mutilva, Navarra, Spain
| | - Carlos Chacón-Díaz
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - María-Jesús de Miguel
- Centro de Investigación y Tecnología Agroalimentaria (CITA), Instituto Agroalimentario de Aragón (IA2), Gobierno de Aragón, Zaragoza, Spain
| | - Pilar-María Muñoz
- Centro de Investigación y Tecnología Agroalimentaria (CITA), Instituto Agroalimentario de Aragón (IA2), Gobierno de Aragón, Zaragoza, Spain
| | - Maite Iriarte
- Instituto de Salud Tropical - Dpto. de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - José-María Blasco
- Centro de Investigación y Tecnología Agroalimentaria (CITA), Instituto Agroalimentario de Aragón (IA2), Gobierno de Aragón, Zaragoza, Spain
| | - María-Jesús Grilló
- Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Mutilva, Navarra, Spain
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Modernized Tools for Streamlined Genetic Manipulation and Comparative Study of Wild and Diverse Proteobacterial Lineages. mBio 2018; 9:mBio.01877-18. [PMID: 30301859 PMCID: PMC6178617 DOI: 10.1128/mbio.01877-18] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
A great challenge in microbiota research is the immense diversity of symbiotic bacteria with the capacity to impact the lives of plants and animals. Moving beyond correlative DNA sequencing-based studies to define the cellular and molecular mechanisms by which symbiotic bacteria influence the biology of their hosts is stalling because genetic manipulation of new and uncharacterized bacterial isolates remains slow and difficult with current genetic tools. Moreover, developing tools de novo is an arduous and time-consuming task and thus represents a significant barrier to progress. To address this problem, we developed a suite of engineering vectors that streamline conventional genetic techniques by improving postconjugation counterselection, modularity, and allelic exchange. Our modernized tools and step-by-step protocols will empower researchers to investigate the inner workings of both established and newly emerging models of bacterial symbiosis. Correlating the presence of bacteria and the genes they carry with aspects of plant and animal biology is rapidly outpacing the functional characterization of naturally occurring symbioses. A major barrier to mechanistic studies is the lack of tools for the efficient genetic manipulation of wild and diverse bacterial isolates. To address the need for improved molecular tools, we used a collection of proteobacterial isolates native to the zebrafish intestinal microbiota as a testbed to construct a series of modernized vectors that expedite genetic knock-in and knockout procedures across lineages. The innovations that we introduce enhance the flexibility of conventional genetic techniques, making it easier to manipulate many different bacterial isolates with a single set of tools. We developed alternative strategies for domestication-free conjugation, designed plasmids with customizable features, and streamlined allelic exchange using visual markers of homologous recombination. We demonstrate the potential of these tools through a comparative study of bacterial behavior within the zebrafish intestine. Live imaging of fluorescently tagged isolates revealed a spectrum of distinct population structures that differ in their biogeography and dominant growth mode (i.e., planktonic versus aggregated). Most striking, we observed divergent genotype-phenotype relationships: several isolates that are predicted by genomic analysis and in vitro assays to be capable of flagellar motility do not display this trait within living hosts. Together, the tools generated in this work provide a new resource for the functional characterization of wild and diverse bacterial lineages that will help speed the research pipeline from sequencing-based correlations to mechanistic underpinnings.
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Liang WF, Sun MY, Cui LY, Zhang C, Xing XH. Cre/loxP-Mediated Multicopy Integration of the Mevalonate Operon into the Genome of Methylobacterium extorquens AM1. Appl Biochem Biotechnol 2017; 185:565-577. [PMID: 29243041 DOI: 10.1007/s12010-017-2673-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Accepted: 11/30/2017] [Indexed: 01/08/2023]
Abstract
Methylobacterium extorquens AM1 is the model strain for methylotrophic bacteria that metabolize methanol as the sole carbon and energy source. Genetically modified M. extorquens AM1 is used as a methylotrophic cell factory (MeCF) for high value-added chemical production. We tested the Cre-loxP recombination system for its ability to mediate multicopy gene integration of the mvt3 operon (mvt3) in M. extorquens AM1. mvt3 controls the expression of the first three enzymes of the mevalonate synthesis pathway. We assayed for Cre-mediated multigene integration by screening for multicopy mutants via their survival in culture with a high kanamycin concentration (600 μg/mL). We identified mutant strains in which the mevalonate titer was increased by up to 1.9-fold compared with M2 (M. extorquens AM1ΔcelABCΔattTn7::mvt3::loxP) and confirmed mvt3 integration at 2-3 copies per genome. This result demonstrates the feasibility of multicopy integration in M. extorquens AM1 mediated by Cre-loxP recombination and its potential for improving the output of M. extorquens AM1 metabolic pathways, e.g., optimization of terpenoid synthesis.
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Affiliation(s)
- Wei-Fan Liang
- Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Center for Synthetic and Systems Biology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, People's Republic of China
- Guangdong Hainabiotech CO., LTD, Foshan, 511400, People's Republic of China
| | - Ming-Yang Sun
- Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Center for Synthetic and Systems Biology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, People's Republic of China
| | - Lan-Yu Cui
- Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Center for Synthetic and Systems Biology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, People's Republic of China
| | - Chong Zhang
- Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Center for Synthetic and Systems Biology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, People's Republic of China.
| | - Xin-Hui Xing
- Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Center for Synthetic and Systems Biology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, People's Republic of China
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Chan MK, Lim SK, Miswan N, Chew AL, Noordin R, Khoo BY. Expression of stable and active human DNA topoisomerase I in Pichia pastoris. Protein Expr Purif 2017; 141:52-62. [PMID: 28893606 DOI: 10.1016/j.pep.2017.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/11/2017] [Accepted: 09/07/2017] [Indexed: 10/18/2022]
Abstract
This study described the isolation of the coding region of human topoisomerase I (TopoI) from MDA-MB-231 and the expression of multiple copy recombinant genes in four Pichia pastoris strains. First, polymerase chain reaction (PCR)-amplification of the enzyme coding region was performed. The PCR fragment was cloned into pPICZ-α-A vector and sequenced. It was then transformed into X33, GS115, SMD1168H and KM71H strains of Pichia. PCR-screening for positive clones was performed, and estimation of multiple copy integrants in each Pichia strain was carried out using agar plates containing increasing concentrations of Zeocin®. The selected clones of multiple copy recombinant genes were then induced for TopoI expression in shaker flasks. GS115 and SMD1168 were found to be better Pichia strains to accommodate the recombinant gene for the expression of TopoI extracellularly. However, the DNA relaxation activity revealed that only the target enzyme in the culture supernatants of GS115-pPICZ-α-A-TopoI exhibited consistent enzyme activity over the cultivation time-points. Active enzyme activity was inhibited by Camptothecin. The enzyme produced can be used for in-house gel-based DNA relaxation assay development in performing high throughput screening for target-specific growth inhibitors that display similar effect as the TopoI inhibitors. These inhibitors may contribute to the improvement of the treatment of cancer patients.
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Affiliation(s)
- Mooi Kwai Chan
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Shern Kwok Lim
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Noorizan Miswan
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Ai Lan Chew
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Rahmah Noordin
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Boon Yin Khoo
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 Penang, Malaysia.
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Kranz A, Vogel A, Degner U, Kiefler I, Bott M, Usadel B, Polen T. High precision genome sequencing of engineered Gluconobacter oxydans 621H by combining long nanopore and short accurate Illumina reads. J Biotechnol 2017; 258:197-205. [PMID: 28433722 DOI: 10.1016/j.jbiotec.2017.04.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 04/14/2017] [Accepted: 04/15/2017] [Indexed: 02/08/2023]
Abstract
State of the art and novel high-throughput DNA sequencing technologies enable fascinating opportunities and applications in the life sciences including microbial genomics. Short high-quality read data already enable not only microbial genome sequencing, yet can be inadequately to solve problems in genome assemblies and for the analysis of structural variants, especially in engineered microbial cell factories. Single-molecule real-time sequencing technologies generating long reads promise to solve such assembly problems. In our study, we wanted to increase the average read length of long nanopore reads with R9 chemistry and conducted a hybrid approach for the analysis of structural variants to check the genome stability of a recombinant Gluconobacter oxydans 621H strain (IK003.1) engineered for improved growth. Therefore we combined accurate Illumina sequencing technology and low-cost single-molecule nanopore sequencing using the MinION® device from Oxford Nanopore. In our hybrid approach with a modified library protocol we could increase the average size of nanopore 2D reads to about 18.9kb. Combining the long MinION nanopore reads with the high quality short Illumina reads enabled the assembly of the engineered chromosome into a single contig and comprehensive detection and clarification of 7 structural variants including all three known genetically engineered modifications. We found the genome of IK003.1 was stable over 70 generations of strain handling including 28h of process time in a bioreactor. The long read data revealed a novel 1420 bp transposon-flanked and ORF-containing sequence which was hitherto unknown in the G. oxydans 621H reference. Further analysis and genome sequencing showed that this region is already present in G. oxydans 621H wild-type strains. Our data of G. oxydans 621H wild-type DNA from different resources also revealed in 73 annotated coding sequences about 91 uniform nucleotide differences including InDels. Together, our results contribute to an improved high quality genome reference for G. oxydans 621H which is available via ENA accession PRJEB18739.
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Affiliation(s)
- Angela Kranz
- Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; The Bioeconomy Science Center (BioSC), c/o Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Alexander Vogel
- IBMG: Institute for Biology I, RWTH Aachen University, Worringer Weg 2, 52074 Aachen, Germany; IBG-2 Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; The Bioeconomy Science Center (BioSC), c/o Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Ursula Degner
- Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; The Bioeconomy Science Center (BioSC), c/o Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Ines Kiefler
- Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; The Bioeconomy Science Center (BioSC), c/o Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Michael Bott
- Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; The Bioeconomy Science Center (BioSC), c/o Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Björn Usadel
- IBMG: Institute for Biology I, RWTH Aachen University, Worringer Weg 2, 52074 Aachen, Germany; IBG-2 Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; The Bioeconomy Science Center (BioSC), c/o Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Tino Polen
- Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany; The Bioeconomy Science Center (BioSC), c/o Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
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Production of 2-Hydroxyisobutyric Acid from Methanol by Methylobacterium extorquens AM1 Expressing (R)-3-Hydroxybutyryl Coenzyme A-Isomerizing Enzymes. Appl Environ Microbiol 2017; 83:AEM.02622-16. [PMID: 27836853 DOI: 10.1128/aem.02622-16] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 11/08/2016] [Indexed: 01/05/2023] Open
Abstract
The biotechnological production of the methyl methacrylate precursor 2-hydroxyisobutyric acid (2-HIBA) via bacterial poly-3-hydroxybutyrate (PHB) overflow metabolism requires suitable (R)-3-hydroxybutyryl coenzyme A (CoA)-specific coenzyme B12-dependent mutases (RCM). Here, we characterized a predicted mutase from Bacillus massiliosenegalensis JC6 as a mesophilic RCM closely related to the thermophilic enzyme previously identified in Kyrpidia tusciae DSM 2912 (M.-T. Weichler et al., Appl Environ Microbiol 81:4564-4572, 2015, https://doi.org/10.1128/AEM.00716-15). Using both RCM variants, 2-HIBA production from methanol was studied in fed-batch bioreactor experiments with recombinant Methylobacterium extorquens AM1. After complete nitrogen consumption, the concomitant formation of PHB and 2-HIBA was achieved, indicating that both sets of RCM genes were successfully expressed. However, although identical vector systems and incubation conditions were chosen, the metabolic activity of the variant bearing the RCM genes from strain DSM 2912 was severely inhibited, likely due to the negative effects caused by heterologous expression. In contrast, the biomass yield of the variant expressing the JC6 genes was close to the wild-type performance, and 2-HIBA titers of 2.1 g liter-1 could be demonstrated. In this case, up to 24% of the substrate channeled into overflow metabolism was converted to the mutase product, and maximal combined 2-HIBA plus PHB yields from methanol of 0.11 g g-1 were achieved. Reverse transcription-quantitative PCR analysis revealed that metabolic genes, such as methanol dehydrogenase and acetoacetyl-CoA reductase genes, are strongly downregulated after exponential growth, which currently prevents a prolonged overflow phase, thus preventing higher product yields with strain AM1. IMPORTANCE In this study, we genetically modified a methylotrophic bacterium in order to channel intermediates of its overflow metabolism to the C4 carboxylic acid 2-hydroxyisobutyric acid, a precursor of acrylic glass. This has implications for biotechnology, as it shows that reduced C1 substrates, such as methanol and formic acid, can be alternative feedstocks for producing today's commodities. We found that product titers and yields depend more on host physiology than on the activity of the introduced heterologous function modifying the overflow metabolism. In addition, we show that the fitness of recombinant strains substantially varies when they express orthologous genes from different origins. Further studies are needed to extend the overflow production phase in methylotrophic microorganisms for the implementation of biotechnological processes.
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Liang WF, Cui LY, Cui JY, Yu KW, Yang S, Wang TM, Guan CG, Zhang C, Xing XH. Biosensor-assisted transcriptional regulator engineering for Methylobacterium extorquens AM1 to improve mevalonate synthesis by increasing the acetyl-CoA supply. Metab Eng 2016; 39:159-168. [PMID: 27919791 DOI: 10.1016/j.ymben.2016.11.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 11/08/2016] [Accepted: 11/28/2016] [Indexed: 12/28/2022]
Abstract
Acetyl-CoA is not only an important intermediate metabolite for cells but also a significant precursor for production of industrially interesting metabolites. Methylobacterium extorquens AM1, a model strain of methylotrophic cell factories using methanol as carbon source, is of interest because it produces abundant coenzyme A compounds capable of directing to synthesis of different useful compounds from methanol. However, acetyl-CoA is not always efficiently accumulated in M. extorquens AM1, as it is located in the center of three cyclic central metabolic pathways. Here we successfully demonstrated a strategy for sensor-assisted transcriptional regulator engineering (SATRE) to control metabolic flux re-distribution to increase acetyl-CoA flux from methanol for mevalonate production in M. extorquens AM1 with introduction of mevalonate synthesis pathway. A mevalonate biosensor was constructed and we succeeded in isolating a mutated strain (Q49) with a 60% increase in mevalonate concentration (an acetyl-CoA-derived product) following sensor-based high-throughput screening of a QscR transcriptional regulator library. The mutated QscR-49 regulator (Q8*,T61S,N72Y,E160V) lost an N-terminal α-helix and underwent a change in the secondary structure of the RD-I domain at the C terminus, two regions that are related to its interaction with DNA. 13C labeling analysis revealed that acetyl-CoA flux was improved by 7% and transcriptional analysis revealed that QscR had global effects and that two key points, NADPH generation and fumC overexpression, might contribute to the carbon flux re-distribution. A fed-batch fermentation in a 5-L bioreactor for QscR-49 mutant yielded a mevalonate concentration of 2.67g/L, which was equivalent to an overall yield of 0.055mol acetyl-CoA/mol methanol, the highest yield among engineered strains of M. extorquens AM1. This work was the first attempt to regulate M. extorquens AM1 on transcriptional level and provided molecular insights into the mechanism of carbon flux regulation.
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Affiliation(s)
- Wei-Fan Liang
- Key Laboratory for Industrial Biocatalysis, Ministry of Education; Department of Chemical Engineering, Center for Synthetic & System Biology, Tsinghua University, Beijing 100084, China
| | - Lan-Yu Cui
- Key Laboratory for Industrial Biocatalysis, Ministry of Education; Department of Chemical Engineering, Center for Synthetic & System Biology, Tsinghua University, Beijing 100084, China
| | - Jin-Yu Cui
- School of Life Sciences, Qingdao Agricultural University, Qingdao 266109, China
| | - Kai-Wen Yu
- College of Chemistry and Molecular Engineering, Peking University, Beijing 10084, China
| | - Song Yang
- School of Life Sciences, Qingdao Agricultural University, Qingdao 266109, China
| | - Tian-Min Wang
- Key Laboratory for Industrial Biocatalysis, Ministry of Education; Department of Chemical Engineering, Center for Synthetic & System Biology, Tsinghua University, Beijing 100084, China
| | - Chang-Ge Guan
- Key Laboratory for Industrial Biocatalysis, Ministry of Education; Department of Chemical Engineering, Center for Synthetic & System Biology, Tsinghua University, Beijing 100084, China
| | - Chong Zhang
- Key Laboratory for Industrial Biocatalysis, Ministry of Education; Department of Chemical Engineering, Center for Synthetic & System Biology, Tsinghua University, Beijing 100084, China.
| | - Xin-Hui Xing
- Key Laboratory for Industrial Biocatalysis, Ministry of Education; Department of Chemical Engineering, Center for Synthetic & System Biology, Tsinghua University, Beijing 100084, China
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Metabolic footprint of epiphytic bacteria on Arabidopsis thaliana leaves. ISME JOURNAL 2015; 10:632-43. [PMID: 26305156 DOI: 10.1038/ismej.2015.141] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 06/03/2015] [Accepted: 07/01/2015] [Indexed: 02/08/2023]
Abstract
The phyllosphere, which is defined as the parts of terrestrial plants above the ground, is a large habitat for different microorganisms that show a high extent of adaption to their environment. A number of hypotheses were generated by culture-independent functional genomics studies to explain the competitiveness of specialized bacteria in the phyllosphere. In contrast, in situ data at the metabolome level as a function of bacterial colonization are lacking. Here, we aimed to obtain new insights into the metabolic interplay between host and epiphytes upon colonization of Arabidopsis thaliana leaves in a controlled laboratory setting using environmental metabolomics approaches. Quantitative nuclear magnetic resonance (NMR) and imaging high-resolution mass spectrometry (IMS) methods were used to identify Arabidopsis leaf surface compounds and their possible involvement in the epiphytic lifestyle by relative changes in compound pools. The dominant carbohydrates on the leaf surfaces were sucrose, fructose and glucose. These sugars were significantly and specifically altered after epiphytic leaf colonization by the organoheterotroph Sphingomonas melonis or the phytopathogen Pseudomonas syringae pv. tomato, but only to a minor extent by the methylotroph Methylobacterium extorquens. In addition to carbohydrates, IMS revealed surprising alterations in arginine metabolism and phytoalexin biosynthesis that were dependent on the presence of bacteria, which might reflect the consequences of bacterial activity and the recognition of not only pathogens but also commensals by the plant. These results highlight the power of environmental metabolomics to aid in elucidating the molecular basis underlying plant-epiphyte interactions in situ.
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Schada von Borzyskowski L, Remus-Emsermann M, Weishaupt R, Vorholt JA, Erb TJ. A set of versatile brick vectors and promoters for the assembly, expression, and integration of synthetic operons in Methylobacterium extorquens AM1 and other alphaproteobacteria. ACS Synth Biol 2015; 4:430-43. [PMID: 25105793 DOI: 10.1021/sb500221v] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The discipline of synthetic biology requires standardized tools and genetic elements to construct novel functionalities in microorganisms; yet, many model systems still lack such tools. Here, we describe a novel set of vectors that allows the convenient construction of synthetic operons in Methylobacterium extorquens AM1, an important alphaproteobacterial model organism for methylotrophy and a promising platform organism for methanol-based biotechnology. In addition, we provide a set of constitutive alphaproteobacterial promoters of different strengths that were characterized in detail by two approaches: on the single-cell scale and on the cell population level. Finally, we describe a straightforward strategy to deliver synthetic constructs to the genome of M. extorquens AM1 and other Alphaproteobacteria. This study defines a new standard to systematically characterize genetic parts for their use in M. extorquens AM1 by using single-cell fluorescence microscopy and opens the toolbox for synthetic biological applications in M. extorquens AM1 and other alphaproteobacterial model systems.
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Affiliation(s)
- Lennart Schada von Borzyskowski
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zurich, Vladimir-Prelog-Weg
4, 8093 Zurich, Switzerland
| | - Mitja Remus-Emsermann
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zurich, Vladimir-Prelog-Weg
4, 8093 Zurich, Switzerland
| | - Ramon Weishaupt
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zurich, Vladimir-Prelog-Weg
4, 8093 Zurich, Switzerland
| | - Julia A. Vorholt
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zurich, Vladimir-Prelog-Weg
4, 8093 Zurich, Switzerland
| | - Tobias J. Erb
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zurich, Vladimir-Prelog-Weg
4, 8093 Zurich, Switzerland
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Carroll SM, Chubiz LM, Agashe D, Marx CJ. Parallel and Divergent Evolutionary Solutions for the Optimization of an Engineered Central Metabolism in Methylobacterium extorquens AM1. Microorganisms 2015; 3:152-74. [PMID: 27682084 PMCID: PMC5023240 DOI: 10.3390/microorganisms3020152] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 03/30/2015] [Accepted: 04/01/2015] [Indexed: 11/16/2022] Open
Abstract
Bioengineering holds great promise to provide fast and efficient biocatalysts for methanol-based biotechnology, but necessitates proven methods to optimize physiology in engineered strains. Here, we highlight experimental evolution as an effective means for optimizing an engineered Methylobacterium extorquens AM1. Replacement of the native formaldehyde oxidation pathway with a functional analog substantially decreased growth in an engineered Methylobacterium, but growth rapidly recovered after six hundred generations of evolution on methanol. We used whole-genome sequencing to identify the basis of adaptation in eight replicate evolved strains, and examined genomic changes in light of other growth and physiological data. We observed great variety in the numbers and types of mutations that occurred, including instances of parallel mutations at targets that may have been "rationalized" by the bioengineer, plus other "illogical" mutations that demonstrate the ability of evolution to expose unforeseen optimization solutions. Notably, we investigated mutations to RNA polymerase, which provided a massive growth benefit but are linked to highly aberrant transcriptional profiles. Overall, we highlight the power of experimental evolution to present genetic and physiological solutions for strain optimization, particularly in systems where the challenges of engineering are too many or too difficult to overcome via traditional engineering methods.
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Affiliation(s)
- Sean Michael Carroll
- Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.
| | - Lon M Chubiz
- Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.
- Department of Biology, University of Missouri-St. Louis, St. Louis, MO 63103, USA.
| | - Deepa Agashe
- Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.
- National Centre for Biological Sciences, Bangalore 560065, India.
| | - Christopher J Marx
- Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.
- Faculty of Arts and Sciences Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA.
- Department of Biological Sciences, Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, ID 83843, USA.
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New vectors for chromosomal integration enable high-level constitutive or inducible magnetosome expression of fusion proteins in Magnetospirillum gryphiswaldense. Appl Environ Microbiol 2014; 80:2609-16. [PMID: 24532068 DOI: 10.1128/aem.00192-14] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The alphaproteobacterium Magnetospirillum gryphiswaldense biomineralizes magnetosomes, which consist of monocrystalline magnetite cores enveloped by a phospholipid bilayer containing specific proteins. Magnetosomes represent magnetic nanoparticles with unprecedented magnetic and physicochemical characteristics. These make them potentially useful in a number of biotechnological and biomedical applications. Further functionalization can be achieved by expression of foreign proteins via genetic fusion to magnetosome anchor peptides. However, the available genetic tool set for strong and controlled protein expression in magnetotactic bacteria is very limited. Here, we describe versatile vectors for either inducible or high-level constitutive expression of proteins in M. gryphiswaldense. The combination of an engineered native PmamDC promoter with a codon-optimized egfp gene (Mag-egfp) resulted in an 8-fold increase in constitutive expression and in brighter fluorescence. We further demonstrate that the widely used Ptet promoter is functional and tunable in M. gryphiswaldense. Stable and uniform expression of the EGFP and β-glucuronidase (GusA) reporters was achieved by single-copy chromosomal insertion via Tn5-mediated transposition. In addition, gene duplication by Mag-EGFP-EGFP fusions to MamC resulted in further increased magnetosome expression and fluorescence. Between 80 and 210 (for single MamC-Mag-EGFP) and 200 and 520 (for MamC-Mag-EGFP-EGFP) GFP copies were estimated to be expressed per individual magnetosome particle.
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Arpino JAJ, Hancock EJ, Anderson J, Barahona M, Stan GBV, Papachristodoulou A, Polizzi K. Tuning the dials of Synthetic Biology. MICROBIOLOGY-SGM 2013; 159:1236-1253. [PMID: 23704788 PMCID: PMC3749727 DOI: 10.1099/mic.0.067975-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Synthetic Biology is the ‘Engineering of Biology’ – it aims to use a forward-engineering design cycle based on specifications, modelling, analysis, experimental implementation, testing and validation to modify natural or design new, synthetic biology systems so that they behave in a predictable fashion. Motivated by the need for truly plug-and-play synthetic biological components, we present a comprehensive review of ways in which the various parts of a biological system can be modified systematically. In particular, we review the list of ‘dials’ that are available to the designer and discuss how they can be modelled, tuned and implemented. The dials are categorized according to whether they operate at the global, transcriptional, translational or post-translational level and the resolution that they operate at. We end this review with a discussion on the relative advantages and disadvantages of some dials over others.
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Affiliation(s)
- James A J Arpino
- Centre for Synthetic Biology and Innovation, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.,Department of Mathematics, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.,Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Edward J Hancock
- Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
| | - James Anderson
- St John's College, St Giles, Oxford OX1 3JP, UK.,Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
| | - Mauricio Barahona
- Department of Mathematics, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Guy-Bart V Stan
- Department of Bioengineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.,Centre for Synthetic Biology and Innovation, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | | | - Karen Polizzi
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.,Centre for Synthetic Biology and Innovation, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
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Yu Q, Li Y, Ma A, Liu W, Wang H, Zhuang G. An efficient design strategy for a whole-cell biosensor based on engineered ribosome binding sequences. Anal Bioanal Chem 2011; 401:2891-8. [PMID: 21947012 DOI: 10.1007/s00216-011-5411-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2011] [Revised: 08/16/2011] [Accepted: 09/06/2011] [Indexed: 10/17/2022]
Abstract
In prokaryotes, the ribosome binding sequence (RBS), located in the 5' untranslated region (5' UTR) of an mRNA, plays a critical role in enhancing mRNA translation and stability. To evaluate the effect of the RBS on the sensitivity and signal intensity of an environmental whole-cell biosensor, three Escherichia coli-based biosensors that respond to benzene, toluene, ethylbenzene, and the xylenes (BTEX) were constructed; the three biosensors have the same Pu promoter and xylR regulator from the Pseudomonas putida TOL plasmid but differ in the engineered RBS in their reporter genes. The results from time and dose-dependent induction of luminescence activity by 2-chlorotoluene showed that the BTEX-SE and BTEX-SD biosensors with engineered RBS had signal intensities approximately 10-35 times higher than the primary BTEX-W biosensor. The limits of detection (LOD) of the BTEX-SE and BTEX-SD biosensors were also significantly lower than the LOD of the BTEX-W biosensor (20 ± 5 μmol L(-1) and 25 ± 5 μmol L(-1) vs. 120 ± 10 μmol L(-1)). Moreover, the BTEX-SE and BTEX-SD biosensors responded three times more rapidly to the analytes. These results suggest that rationally designed RBS in the 5' UTR of a reporter gene may be a promising strategy for increasing the sensitivity, signal intensity, and response speed of whole-cell biosensors.
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Affiliation(s)
- Qing Yu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
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Application of the bacteriophage Mu-driven system for the integration/amplification of target genes in the chromosomes of engineered Gram-negative bacteria--mini review. Appl Microbiol Biotechnol 2011; 91:857-71. [PMID: 21698377 PMCID: PMC3145075 DOI: 10.1007/s00253-011-3416-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 05/24/2011] [Accepted: 05/24/2011] [Indexed: 11/04/2022]
Abstract
The advantages of phage Mu transposition-based systems for the chromosomal editing of plasmid-less strains are reviewed. The cis and trans requirements for Mu phage-mediated transposition, which include the L/R ends of the Mu DNA, the transposition factors MuA and MuB, and the cis/trans functioning of the E element as an enhancer, are presented. Mini-Mu(LR)/(LER) units are Mu derivatives that lack most of the Mu genes but contain the L/R ends or a properly arranged E element in cis to the L/R ends. The dual-component system, which consists of an integrative plasmid with a mini-Mu and an easily eliminated helper plasmid encoding inducible transposition factors, is described in detail as a tool for the integration/amplification of recombinant DNAs. This chromosomal editing method is based on replicative transposition through the formation of a cointegrate that can be resolved in a recombination-dependent manner. (E-plus)- or (E-minus)-helpers that differ in the presence of the trans-acting E element are used to achieve the proper mini-Mu transposition intensity. The systems that have been developed for the construction of stably maintained mini-Mu multi-integrant strains of Escherichia coli and Methylophilus methylotrophus are described. A novel integration/amplification/fixation strategy is proposed for consecutive independent replicative transpositions of different mini-Mu(LER) units with “excisable” E elements in methylotrophic cells.
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FURUHATA KATSUNORI, BANZAI AZUSAU, KAWAKAMI YASUSHI, ISHIZAKI NAOTO, YOSHIDA YOSHIHIRO, GOTO KEIICHI, FUKUYAMA MASAFUMI. Genotyping and Chlorine-Resistance of Methylobacterium aquaticum Isolated from Water Samples in Japan. Biocontrol Sci 2011; 16:103-7. [DOI: 10.4265/bio.16.103] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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Höfer P, Choi YJ, Osborne MJ, Miguez CB, Vermette P, Groleau D. Production of functionalized polyhydroxyalkanoates by genetically modified Methylobacterium extorquens strains. Microb Cell Fact 2010; 9:70. [PMID: 20846434 PMCID: PMC2954876 DOI: 10.1186/1475-2859-9-70] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 09/16/2010] [Indexed: 11/16/2022] Open
Abstract
Background Methylotrophic (methanol-utilizing) bacteria offer great potential as cell factories in the production of numerous products from biomass-derived methanol. Bio-methanol is essentially a non-food substrate, an advantage over sugar-utilizing cell factories. Low-value products as well as fine chemicals and advanced materials are envisageable from methanol. For example, several methylotrophic bacteria, including Methylobacterium extorquens, can produce large quantities of the biodegradable polyester polyhydroxybutyric acid (PHB), the best known polyhydroxyalkanoate (PHA). With the purpose of producing second-generation PHAs with increased value, we have explored the feasibility of using M. extorquens for producing functionalized PHAs containing C-C double bonds, thus, making them amenable to future chemical/biochemical modifications for high value applications. Results Our proprietary M. extorquens ATCC 55366 was found unable to yield functionalized PHAs when fed methanol and selected unsaturated carboxylic acids as secondary substrates. However, cloning of either the phaC1 or the phaC2 gene from P. fluorescens GK13, using an inducible and regulated expression system based on cumate as inducer (the cumate switch), yielded recombinant M. extorquens strains capable of incorporating modest quantities of C-C double bonds into PHA, starting from either C6= and/or C8=. The two recombinant strains gave poor results with C11=. The strain containing the phaC2 gene was better at using C8= and at incorporating C-C double bonds into PHA. Solvent fractioning indicated that the produced polymers were PHA blends that consequently originated from independent actions of the native and the recombinant PHA synthases. Conclusions This work constitutes an example of metabolic engineering applied to the construction of a methanol-utilizing bacterium capable of producing functionalized PHAs containing C-C double bonds. In this regard, the PhaC2 synthase appeared superior to the PhaC1 synthase at utilizing C8= as source of C-C double bonds and at incorporating C-C double bonds into PHA from either C6= or C8=. The M. ex-phaC2 strain is, therefore, a promising biocatalyst for generating advanced (functionalized) PHAs for future high value applications in various fields.
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Affiliation(s)
- Philipp Höfer
- Microbial and Enzymatic Technology Group, Bioprocess Centre, Biotechnology Research Institute, National Research Council Canada, 6100 Royalmount Avenue, Montréal, Québec, H4P 2R2, Canada
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Verginer M, Siegmund B, Cardinale M, Müller H, Choi Y, Míguez CB, Leitner E, Berg G. Monitoring the plant epiphyte Methylobacterium extorquens DSM 21961 by real-time PCR and its influence on the strawberry flavor. FEMS Microbiol Ecol 2010; 74:136-45. [DOI: 10.1111/j.1574-6941.2010.00942.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Methanol-based industrial biotechnology: current status and future perspectives of methylotrophic bacteria. Trends Biotechnol 2008; 27:107-15. [PMID: 19111927 DOI: 10.1016/j.tibtech.2008.10.009] [Citation(s) in RCA: 185] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Revised: 10/24/2008] [Accepted: 10/29/2008] [Indexed: 11/21/2022]
Abstract
Methanol is one of the building blocks in the chemical industry and can be synthesized either from petrochemical or renewable resources, such as biogas. Bioprocess technology with methylotrophic bacteria is well established, as illustrated by large-scale single-cell protein production in the past. During recent years, the first genomes of methylotrophs have been sequenced and significant progress in elucidating their metabolism has been made. In addition, the tool set for genetic engineering of methylotrophic bacteria has expanded greatly and strategies to produce fine and bulk chemicals with methylotrophs have been described. This review highlights the potential of these bacteria for the development of economically competitive bioprocesses based on methanol as an alternative carbon source, bringing together biological, technical and economic considerations.
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Abalakina EG, Tokmakova IL, Gorshkova NV, Gak ER, Akhverdyan VZ, Mashko SV, Yomantas YAV. Phage Mu-driven two-plasmid system for integration of recombinant DNA in the Methylophilus methylotrophus genome. Appl Microbiol Biotechnol 2008; 81:191-200. [PMID: 18820908 PMCID: PMC7419445 DOI: 10.1007/s00253-008-1696-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Revised: 08/27/2008] [Accepted: 09/01/2008] [Indexed: 11/18/2022]
Abstract
A phage Mu-driven two-plasmid system for DNA integration in Escherichia coli genome has been adjusted for Methylophilus methylotrophus. Constructed helper plasmids with broad-host-range replicons carry thermo-inducible genes for transposition factors MuA and MuB. Integrative plasmids that are only replicated in E. coli could be mobilized to M. methylotrophus and contained mini-Mu unit with a short terminus of Mu DNA, Mu-attL/R. Mini-Mu unit was integrated in the M. methylotrophus genome via mobilization of the integrative plasmid to the cells carrying the helper in conditions of thermo-induced expression of MuA and MuB. In this system, mini-Mu unit was mainly integrated due to replicative transposition, and the integrated copy could be amplified in the M. methylotrophus chromosome in the presence of helper plasmid. A kan-gene flanked by FRT sites was inserted in one of the mini-Mu units, and it could be readily excised by yeast FLP recombinase that is encoded by the designed plasmid. The multiple Mu-driven gene insertion was carried out by integration of the Bacillus amyloliquefaciens α-amylase gene followed by curing the KmR marker before integration of the second mini-Mu unit with Pseudomonas putida xylE gene encoding catechol 2,3-dioxygenase (C23O).
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Affiliation(s)
- Elena G Abalakina
- Ajinomoto-Genetika Research Institute, 117545, Moscow, Russian Federation
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Production of an insecticidal crystal protein from Bacillus thuringiensis by the methylotroph Methylobacterium extorquens. Appl Environ Microbiol 2008; 74:5178-82. [PMID: 18552184 DOI: 10.1128/aem.00598-08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Cry1Aa protein from Bacillus thuringiensis is an insecticidal protein that is highly active against several species of Lepidoptera. We cloned and expressed the cry1Aa gene in a plant-colonizing methylotroph, Methylobacterium extorquens, under the control of the strong M. extorquens AM1 methanol dehydrogenase promoter, P(mxaF). Transmission electron microscopy revealed characteristic bipyramidal intracellular delta-endotoxin crystals similar to the crystalline inclusions formed by B. thuringiensis. Both the protoxin protein and the activated toxin were visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western analysis. In single-dose assays of the recombinant against the silkworm, Bombyx mori, both whole cells and cell lysates caused rapid feeding inhibition followed by mortality. The biomass and growth rate of recombinant cells in shake flask culture were similar to those of the wild-type strain, indicating a lack of fitness cost to the recombinant under controlled culture conditions. Recombinant Cry1Aa was expressed at a level of 4.5% of total M. extorquens cell protein. The potential benefits of modifying M. extorquens to deliver insecticidal Cry proteins for crop and forest protection are discussed.
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Choi YJ, Morel L, Bourque D, Mullick A, Massie B, Míguez CB. Bestowing inducibility on the cloned methanol dehydrogenase promoter (PmxaF) of Methylobacterium extorquens by applying regulatory elements of Pseudomonas putida F1. Appl Environ Microbiol 2006; 72:7723-9. [PMID: 17041156 PMCID: PMC1694210 DOI: 10.1128/aem.02002-06] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PmxaF is a strong methanol-inducible promoter in Methylobacterium extorquens. When this promoter is cloned in expression vectors and used to drive heterologous gene expression, methanol inducibility is either greatly reduced or entirely lost. In order to bestow inducibility upon the cloned PmxaF promoter in expression vectors, we adopted combinational methods (regulatory elements of the Pseudomonas putida F1 cym and cmt operons and Tn7 transposon system) to control reporter gene expression at the transcriptional level in M. extorquens. An operator fragment (26 nucleotides) of the cmt operon was inserted downstream of the cloned PmxaF promoter in the broad-host-range expression vector (pCHOI3). The repressor gene (cymR) located upstream of the cym operon in P. putida F1 was amplified by PCR. To avoid cellular toxicity for M. extorquens caused by the overexpression of CymR, single and/or double copies of cymR were integrated into the chromosome of M. extorquens using the mini-Tn7 transposon system. Cultures containing the chromosomally integrated cymR gene were subsequently transformed with pCHOI3 containing modified PmxaF (i.e., PmxaF plus operator). In this construct, inducibility is afforded by cumate (p-isopropylbenzoate). In this report, we describe the inducible and tightly regulated expression of heterologous genes (bgl [for beta-galactosidase], est [for esterase], and gfp [for green fluorescent protein]) in M. extorquens. This is the first documented example of an inducible/regulated heterologous gene expression system in M. extorquens.
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Affiliation(s)
- Young J Choi
- Microbial and Enzymatic Technology Group, Bioprocess Sector, Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Ave., Montreal, Quebec H4P 2R2, Canada
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McKenzie GJ, Craig NL. Fast, easy and efficient: site-specific insertion of transgenes into enterobacterial chromosomes using Tn7 without need for selection of the insertion event. BMC Microbiol 2006; 6:39. [PMID: 16646962 PMCID: PMC1475584 DOI: 10.1186/1471-2180-6-39] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Accepted: 04/28/2006] [Indexed: 11/20/2022] Open
Abstract
Background Inserting transgenes into bacterial chromosomes is generally quite involved, requiring a selection for cells carrying the insertion, usually for drug-resistance, or multiple cumbersome manipulations, or both. Several approaches use phage λ red recombination, which allows for the possibility of mutagenesis of the transgene during a PCR step. Results We present a simple, rapid and highly efficient method for transgene insertion into the chromosome of Escherichia coli, Salmonella or Shigella at a benign chromosomal site using the site-specific recombination machinery of the transposon Tn7. This method requires very few manipulations. The transgene is cloned into a temperature-sensitive delivery plasmid and transformed into bacterial cells. Growth at the permissive temperature with induction of the recombination machinery leads to transgene insertion, and subsequent growth at the nonpermissive temperature cures the delivery plasmid. Transgene insertion is highly site-specific, generating insertions solely at the Tn7 attachment site and so efficient that it is not necessary to select for the insertion. Conclusion This method is more efficient and straightforward than other techniques for transgene insertion available for E. coli and related bacteria, making moving transgenes from plasmids to a chromosomal location a simple matter. The non-requirement for selection is particularly well suited for use in development of unmarked strains for environmental release, such as live-vector vaccine strains, and also for promoter-fusion studies, and experiments in which every bacterial cell must express a transgene construct.
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Affiliation(s)
- Gregory J McKenzie
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Nancy L Craig
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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