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Blombach F, Werner F. Chromatin and gene regulation in archaea. Mol Microbiol 2024. [PMID: 39096085 DOI: 10.1111/mmi.15302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Revised: 07/12/2024] [Accepted: 07/16/2024] [Indexed: 08/04/2024]
Abstract
The chromatinisation of DNA by nucleoid-associated proteins (NAPs) in archaea 'formats' the genome structure in profound ways, revealing both striking differences and analogies to eukaryotic chromatin. However, the extent to which archaeal NAPs actively regulate gene expression remains poorly understood. The dawn of quantitative chromatin mapping techniques and first NAP-specific occupancy profiles in different archaea promise a more accurate view. A picture emerges where in diverse archaea with very different NAP repertoires chromatin maintains access to regulatory motifs including the gene promoter independently of transcription activity. Our re-analysis of genome-wide occupancy data of the crenarchaeal NAP Cren7 shows that these chromatin-free regions are flanked by increased Cren7 binding across the transcription start site. While bacterial NAPs often form heterochromatin-like regions across islands with xenogeneic genes that are transcriptionally silenced, there is little evidence for similar structures in archaea and data from Haloferax show that the promoters of xenogeneic genes remain accessible. Local changes in chromatinisation causing wide-ranging effects on transcription restricted to one chromosomal interaction domain (CID) in Saccharolobus islandicus hint at a higher-order level of organisation between chromatin and transcription. The emerging challenge is to integrate results obtained at microscale and macroscale, reconciling molecular structure and function with dynamic genome-wide chromatin landscapes.
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Affiliation(s)
- Fabian Blombach
- Division of Biosciences, RNAP Laboratory, Institute of Structural and Molecular Biology (ISMB), University College London, London, UK
| | - Finn Werner
- Division of Biosciences, RNAP Laboratory, Institute of Structural and Molecular Biology (ISMB), University College London, London, UK
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2
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Nie M, Wang J, Chen Z, Cao C, Zhang K. Systematic engineering enables efficient biosynthesis of L-phenylalanine in E. coli from inexpensive aromatic precursors. Microb Cell Fact 2024; 23:12. [PMID: 38183119 PMCID: PMC10768146 DOI: 10.1186/s12934-023-02282-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 12/19/2023] [Indexed: 01/07/2024] Open
Abstract
BACKGROUND L-phenylalanine is an essential amino acid with various promising applications. The microbial pathway for L-phenylalanine synthesis from glucose in wild strains involves lengthy steps and stringent feedback regulation that limits the production yield. It is attractive to find other candidates, which could be used to establish a succinct and cost-effective pathway for L-phenylalanine production. Here, we developed an artificial bioconversion process to synthesize L-phenylalanine from inexpensive aromatic precursors (benzaldehyde or benzyl alcohol). In particular, this work opens the possibility of L-phenylalanine production from benzyl alcohol in a cofactor self-sufficient system without any addition of reductant. RESULTS The engineered L-phenylalanine biosynthesis pathway comprises two modules: in the first module, aromatic precursors and glycine were converted into phenylpyruvate, the key precursor for L-phenylalanine. The highly active enzyme combination was natural threonine aldolase LtaEP.p and threonine dehydratase A8HB.t, which could produce phenylpyruvate in a titer of 4.3 g/L. Overexpression of gene ridA could further increase phenylpyruvate production by 16.3%, reaching up to 5 g/L. The second module catalyzed phenylpyruvate to L-phenylalanine, and the conversion rate of phenylpyruvate was up to 93% by co-expressing PheDH and FDHV120S. Then, the engineered E. coli containing these two modules could produce L-phenylalanine from benzaldehyde with a conversion rate of 69%. Finally, we expanded the aromatic precursors to produce L-phenylalanine from benzyl alcohol, and firstly constructed the cofactor self-sufficient biosynthetic pathway to synthesize L-phenylalanine without any additional reductant such as formate. CONCLUSION Systematical bioconversion processes have been designed and constructed, which could provide a potential bio-based strategy for the production of high-value L-phenylalanine from low-cost starting materials aromatic precursors.
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Affiliation(s)
- Mengzhen Nie
- Zhejiang University, Hangzhou, 310027, Zhejiang, China
- Center of Synthetic Biology and Integrated Bioengineering, School of Engineering, Westlake University, Hangzhou, 310030, Zhejiang, China
| | - Jingyu Wang
- Center of Synthetic Biology and Integrated Bioengineering, School of Engineering, Westlake University, Hangzhou, 310030, Zhejiang, China
| | - Zeyao Chen
- Zhejiang University, Hangzhou, 310027, Zhejiang, China
- Center of Synthetic Biology and Integrated Bioengineering, School of Engineering, Westlake University, Hangzhou, 310030, Zhejiang, China
| | - Chenkai Cao
- Zhejiang University, Hangzhou, 310027, Zhejiang, China
- Center of Synthetic Biology and Integrated Bioengineering, School of Engineering, Westlake University, Hangzhou, 310030, Zhejiang, China
| | - Kechun Zhang
- Center of Synthetic Biology and Integrated Bioengineering, School of Engineering, Westlake University, Hangzhou, 310030, Zhejiang, China.
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3
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González-González RB, Flores-Contreras EA, González-González E, Torres Castillo NE, Parra-Saldívar R, Iqbal HMN. Biosensor Constructs for the Monitoring of Persistent Emerging Pollutants in Environmental Matrices. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c00421] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
| | | | | | | | | | - Hafiz M. N. Iqbal
- Tecnologico de Monterrey, School of Engineering and Sciences, Monterrey 64849, Mexico
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4
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Sybers D, Joka Bernauw A, El Masri D, Ramadan Maklad H, Charlier D, De Mey M, Bervoets I, Peeters E. Engineering transcriptional regulation in Escherichia coli using an archaeal TetR-family transcription factor. Gene 2022; 809:146010. [PMID: 34688814 DOI: 10.1016/j.gene.2021.146010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/28/2021] [Accepted: 10/11/2021] [Indexed: 11/24/2022]
Abstract
Synthetic biology requires well-characterized biological parts that can be combined into functional modules. One type of biological parts are transcriptional regulators and their cognate operator elements, which enable to either generate an input-specific response or are used as actuator modules. A range of regulators has already been characterized and used for orthogonal gene expression engineering, however, previous efforts have mostly focused on bacterial regulators. This work aims to design and explore the use of an archaeal TetR family regulator, FadRSa from Sulfolobus acidocaldarius, in a bacterial system, namely Escherichia coli. This is a challenging objective given the fundamental difference between the bacterial and archaeal transcription machinery and the lack of a native TetR-like FadR regulatory system in E. coli. The synthetic σ70-dependent bacterial promoter proD was used as a starting point to design hybrid bacterial/archaeal promoter/operator regions, in combination with the mKate2 fluorescent reporter enabling a readout. Four variations of proD containing FadRSa binding sites were constructed and characterized. While expressional activity of the modified promoter proD was found to be severely diminished for two of the constructs, constructs in which the binding site was introduced adjacent to the -35 promoter element still displayed sufficient basal transcriptional activity and showed up to 7-fold repression upon expression of FadRSa. Addition of acyl-CoA has been shown to disrupt FadRSa binding to the DNA in vitro. However, extracellular concentrations of up to 2 mM dodecanoate, subsequently converted to acyl-CoA by the cell, did not have a significant effect on repression in the bacterial system. This work demonstrates that archaeal transcription regulators can be used to generate actuator elements for use in E. coli, although the lack of ligand response underscores the challenge of maintaining biological function when transferring parts to a phylogenetically divergent host.
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Affiliation(s)
- David Sybers
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Amber Joka Bernauw
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Diala El Masri
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Hassan Ramadan Maklad
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Daniel Charlier
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Marjan De Mey
- Centre for Synthetic Biology, Department of Biotechnology, Ghent University, Coupure Links 653, B-9000 Gent, Belgium
| | - Indra Bervoets
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Eveline Peeters
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
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5
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Zhang J, Pang Q, Wang Q, Qi Q, Wang Q. Modular tuning engineering and versatile applications of genetically encoded biosensors. Crit Rev Biotechnol 2021; 42:1010-1027. [PMID: 34615431 DOI: 10.1080/07388551.2021.1982858] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Genetically encoded biosensors have a diverse range of detectable signals and potential applications in many fields, including metabolism control and high-throughput screening. Their ability to be used in situ with minimal interference to the bioprocess of interest could revolutionize synthetic biology and microbial cell factories. The performance and functions of these biosensors have been extensively studied and have been rapidly improved. We review here current biosensor tuning strategies and attempt to unravel how to obtain ideal biosensor functions through experimental adjustments. Strategies for expanding the biosensor input signals that increases the number of detectable compounds have also been summarized. Finally, different output signals and their practical requirements for biotechnology and biomedical applications and environmental safety concerns have been analyzed. This in-depth review of the responses and regulation mechanisms of genetically encoded biosensors will assist to improve their design and optimization in various application scenarios.
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Affiliation(s)
- Jian Zhang
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, P. R. China
| | - Qingxiao Pang
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, P. R. China
| | - Qi Wang
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, P. R. China
| | - Qingsheng Qi
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, P. R. China.,CAS Key Lab of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, P. R. China
| | - Qian Wang
- National Glycoengineering Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, P. R. China.,CAS Key Lab of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, P. R. China
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6
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LuxAB-Based Microbial Cell Factories for the Sensing, Manufacturing and Transformation of Industrial Aldehydes. Catalysts 2021. [DOI: 10.3390/catal11080953] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The application of genetically encoded biosensors enables the detection of small molecules in living cells and has facilitated the characterization of enzymes, their directed evolution and the engineering of (natural) metabolic pathways. In this work, the LuxAB biosensor system from Photorhabdus luminescens was implemented in Escherichia coli to monitor the enzymatic production of aldehydes from primary alcohols and carboxylic acid substrates. A simple high-throughput assay utilized the bacterial luciferase—previously reported to only accept aliphatic long-chain aldehydes—to detect structurally diverse aldehydes, including aromatic and monoterpene aldehydes. LuxAB was used to screen the substrate scopes of three prokaryotic oxidoreductases: an alcohol dehydrogenase (Pseudomonas putida), a choline oxidase variant (Arthrobacter chlorophenolicus) and a carboxylic acid reductase (Mycobacterium marinum). Consequently, high-value aldehydes such as cinnamaldehyde, citral and citronellal could be produced in vivo in up to 80% yield. Furthermore, the dual role of LuxAB as sensor and monooxygenase, emitting bioluminescence through the oxidation of aldehydes to the corresponding carboxylates, promises implementation in artificial enzyme cascades for the synthesis of carboxylic acids. These findings advance the bio-based detection, preparation and transformation of industrially important aldehydes in living cells.
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7
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Puopolo R, Sorrentino I, Gallo G, Piscitelli A, Giardina P, Le Goff A, Fiorentino G. Self-assembling thermostable chimeras as new platform for arsenic biosensing. Sci Rep 2021; 11:2991. [PMID: 33542380 PMCID: PMC7862302 DOI: 10.1038/s41598-021-82648-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 01/21/2021] [Indexed: 01/30/2023] Open
Abstract
The correct immobilization and orientation of enzymes on nanosurfaces is a crucial step either for the realization of biosensors, as well as to guarantee the efficacy of the developed biomaterials. In this work we produced two versions of a chimeric protein, namely ArsC-Vmh2 and Vmh2-ArsC, which combined the self-assembling properties of Vmh2, a hydrophobin from Pleurotus ostreatus, with that of TtArsC, a thermophilic arsenate reductase from Thermus thermophilus; both chimeras were heterologously expressed in Escherichia coli and purified from inclusion bodies. They were characterized for their enzymatic capability to reduce As(V) into As(III), as well as for their immobilization properties on polystyrene and gold in comparison to the native TtArsC. The chimeric proteins immobilized on polystyrene can be reused up to three times and stored for 15 days with 50% of activity loss. Immobilization on gold electrodes showed that both chimeras follow a classic Langmuir isotherm model towards As(III) recognition, with an association constant (KAsIII) between As(III) and the immobilized enzyme, equal to 650 (± 100) L mol-1 for ArsC-Vmh2 and to 1200 (± 300) L mol-1 for Vmh2-ArsC. The results demonstrate that gold-immobilized ArsC-Vmh2 and Vmh2-ArsC can be exploited as electrochemical biosensors to detect As(III).
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Affiliation(s)
- Rosanna Puopolo
- Department of Biology, University of Naples Federico II, 80126, Naples, Italy
| | - Ilaria Sorrentino
- Department of Molecular Chemistry, CNRS, University Grenoble Alpes, 38000, Grenoble, France
| | - Giovanni Gallo
- Department of Biology, University of Naples Federico II, 80126, Naples, Italy
| | - Alessandra Piscitelli
- Department of Chemical Sciences, University of Naples Federico II, 80126, Naples, Italy
| | - Paola Giardina
- Department of Chemical Sciences, University of Naples Federico II, 80126, Naples, Italy
| | - Alan Le Goff
- Department of Molecular Chemistry, CNRS, University Grenoble Alpes, 38000, Grenoble, France.
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8
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Gonçalves CC, Bruce T, Silva CDOG, Fillho EXF, Noronha EF, Carlquist M, Parachin NS. Bioprospecting Microbial Diversity for Lignin Valorization: Dry and Wet Screening Methods. Front Microbiol 2020; 11:1081. [PMID: 32582068 PMCID: PMC7295907 DOI: 10.3389/fmicb.2020.01081] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 04/30/2020] [Indexed: 01/02/2023] Open
Abstract
Lignin is an abundant cell wall component, and it has been used mainly for generating steam and electricity. Nevertheless, lignin valorization, i.e. the conversion of lignin into high value-added fuels, chemicals, or materials, is crucial for the full implementation of cost-effective lignocellulosic biorefineries. From this perspective, rapid screening methods are crucial for time- and resource-efficient development of novel microbial strains and enzymes with applications in the lignin biorefinery. The present review gives an overview of recent developments and applications of a vast arsenal of activity and sequence-based methodologies for uncovering novel microbial strains with ligninolytic potential, novel enzymes for lignin depolymerization and for unraveling the main metabolic routes during growth on lignin. Finally, perspectives on the use of each of the presented methods and their respective advantages and disadvantages are discussed.
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Affiliation(s)
- Carolyne Caetano Gonçalves
- Department of Genomic Science and Biotechnology, Universidade Católica de Brasília - UCB, Brasília, Brazil
| | - Thiago Bruce
- Department of Genomic Science and Biotechnology, Universidade Católica de Brasília - UCB, Brasília, Brazil
| | | | | | - Eliane Ferreira Noronha
- Laboratory of Enzymology, Department of Cellular Biology, University of Brasília, Brasília, Brazil
| | - Magnus Carlquist
- Division of Applied Microbiology, Department of Chemistry, Faculty of Engineering, Lund University, Lund, Sweden
| | - Nádia Skorupa Parachin
- Department of Genomic Science and Biotechnology, Universidade Católica de Brasília - UCB, Brasília, Brazil
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9
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F M Machado L, Currin A, Dixon N. Directed evolution of the PcaV allosteric transcription factor to generate a biosensor for aromatic aldehydes. J Biol Eng 2019; 13:91. [PMID: 31798685 PMCID: PMC6882365 DOI: 10.1186/s13036-019-0214-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 10/16/2019] [Indexed: 12/27/2022] Open
Abstract
Background Transcription factor-based biosensors are useful tools for the detection of metabolites and industrially valuable molecules, and present many potential applications in biotechnology and biomedicine. However, the most common approach to develop biosensors relies on employing a limited set of naturally occurring allosteric transcription factors (aTFs). Therefore, altering the ligand specificity of aTFs towards the detection of new effectors is an important goal. Results Here, the PcaV repressor, a member of the MarR aTF family, was used to develop a biosensor for the detection of hydroxyl-substituted benzoic acids, including protocatechuic acid (PCA). The PCA biosensor was further subjected to directed evolution to alter its ligand specificity towards vanillin and other closely related aromatic aldehydes, to generate the Van2 biosensor. Ligand recognition of Van2 was explored in vitro using a range of biochemical and biophysical analyses, and extensive in vivo genetic-phenotypic analysis was performed to determine the role of each amino acid change upon biosensor performance. Conclusions This is the first study to report directed evolution of a member of the MarR aTF family, and demonstrates the plasticity of the PCA biosensor by altering its ligand specificity to generate a biosensor for aromatic aldehydes.
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Affiliation(s)
- Leopoldo F M Machado
- 1Manchester Institute of Biotechnology (MIB), The University of Manchester, M1 7DN, Manchester, UK.,2Department of Chemistry, The University of Manchester, M1 7DN, Manchester, UK
| | - Andrew Currin
- 1Manchester Institute of Biotechnology (MIB), The University of Manchester, M1 7DN, Manchester, UK.,2Department of Chemistry, The University of Manchester, M1 7DN, Manchester, UK.,3SYNBIOCHEM, The University of Manchester, M1 7DN, Manchester, UK
| | - Neil Dixon
- 1Manchester Institute of Biotechnology (MIB), The University of Manchester, M1 7DN, Manchester, UK.,2Department of Chemistry, The University of Manchester, M1 7DN, Manchester, UK.,3SYNBIOCHEM, The University of Manchester, M1 7DN, Manchester, UK
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10
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Alvarez-Gonzalez G, Dixon N. Genetically encoded biosensors for lignocellulose valorization. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:246. [PMID: 31636705 PMCID: PMC6792243 DOI: 10.1186/s13068-019-1585-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/05/2019] [Indexed: 05/07/2023]
Abstract
Modern society is hugely dependent on finite oil reserves for the supply of fuels and chemicals. Moving our dependence away from these unsustainable oil-based feedstocks to renewable ones is, therefore, a critical factor towards the development of a low carbon bioeconomy. Lignin derived from biomass feedstocks offers great potential as a renewable source of aromatic compounds if methods for its effective valorization can be developed. Synthetic biology and metabolic engineering offer the potential to synergistically enable the development of cell factories with novel biosynthetic routes to valuable chemicals from these sustainable sources. Pathway design and optimization is, however, a major bottleneck due to the lack of high-throughput methods capable of screening large libraries of genetic variants and the metabolic burden associated with bioproduction. Genetically encoded biosensors can provide a solution by transducing the target metabolite concentration into detectable signals to provide high-throughput phenotypic read-outs and allow dynamic pathway regulation. The development and application of biosensors in the discovery and engineering of efficient biocatalytic processes for the degradation, conversion, and valorization of lignin are paving the way towards a sustainable and economically viable biorefinery.
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Affiliation(s)
| | - Neil Dixon
- Manchester Institute of Biotechnology (MIB), The University of Manchester, Manchester, UK
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11
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The Smell of Synthetic Biology: Engineering Strategies for Aroma Compound Production in Yeast. FERMENTATION-BASEL 2018. [DOI: 10.3390/fermentation4030054] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Yeast—especially Saccharomyces cerevisiae—have long been a preferred workhorse for the production of numerous recombinant proteins and other metabolites. S. cerevisiae is a noteworthy aroma compound producer and has also been exploited to produce foreign bioflavour compounds. In the past few years, important strides have been made in unlocking the key elements in the biochemical pathways involved in the production of many aroma compounds. The expression of these biochemical pathways in yeast often involves the manipulation of the host strain to direct the flux towards certain precursors needed for the production of the given aroma compound. This review highlights recent advances in the bioengineering of yeast—including S. cerevisiae—to produce aroma compounds and bioflavours. To capitalise on recent advances in synthetic yeast genomics, this review presents yeast as a significant producer of bioflavours in a fresh context and proposes new directions for combining engineering and biology principles to improve the yield of targeted aroma compounds.
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12
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Antonucci I, Gallo G, Limauro D, Contursi P, Ribeiro AL, Blesa A, Berenguer J, Bartolucci S, Fiorentino G. Characterization of a promiscuous cadmium and arsenic resistance mechanism in Thermus thermophilus HB27 and potential application of a novel bioreporter system. Microb Cell Fact 2018; 17:78. [PMID: 29776370 PMCID: PMC5960188 DOI: 10.1186/s12934-018-0918-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 05/03/2018] [Indexed: 11/21/2022] Open
Abstract
Background The characterization of the molecular determinants of metal resistance has potential biotechnological application in biosensing and bioremediation. In this context, the bacterium Thermus thermophilus HB27 is a metal tolerant thermophile containing a set of genes involved in arsenic resistance which, differently from other microbes, are not organized into a single operon. They encode the proteins: arsenate reductase, TtArsC, arsenic efflux membrane transporter, TtArsX, and transcriptional repressor, TtSmtB. Results In this work we show that the arsenic efflux protein TtArsX and the arsenic responsive transcriptional repressor TtSmtB are required to provide resistance to cadmium. We analyzed the sensitivity to Cd(II) of mutants lacking TtArsX, finding that they are more sensitive to this metal than the wild type strain. In addition, using promoter probe reporter plasmids, we show that the transcription of TtarsX is also stimulated by the presence of Cd(II) in a TtSmtB-dependent way. Actually, a regulatory circuit composed of TtSmtB and a reporter gene expressed from the TtarsX promoter responds to variation in Cd(II), As(III) and As(V) concentrations. Conclusions Our results demonstrate that the system composed by TtSmtB and TtArsX is responsible for both the arsenic and cadmium resistance in T. thermophilus. The data also support the use of T. thermophilus as a suitable chassis for the design and development of As-Cd biosensors. Electronic supplementary material The online version of this article (10.1186/s12934-018-0918-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Immacolata Antonucci
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Naples, Italy
| | - Giovanni Gallo
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Naples, Italy
| | - Danila Limauro
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Naples, Italy
| | - Patrizia Contursi
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Naples, Italy
| | - Ana Luisa Ribeiro
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Campus Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Alba Blesa
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Campus Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - José Berenguer
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Campus Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Simonetta Bartolucci
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Naples, Italy
| | - Gabriella Fiorentino
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Naples, Italy.
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13
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Liu C, Zhang B, Liu YM, Yang KQ, Liu SJ. New Intracellular Shikimic Acid Biosensor for Monitoring Shikimate Synthesis in Corynebacterium glutamicum. ACS Synth Biol 2018; 7:591-601. [PMID: 29087704 DOI: 10.1021/acssynbio.7b00339] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The quantitative monitoring of intracellular metabolites with in vivo biosensors provides an efficient means of identifying high-yield strains and observing product accumulation in real time. In this study, a shikimic acid (SA) biosensor was constructed from a LysR-type transcriptional regulator (ShiR) of Corynebacterium glutamicum. The SA biosensor specifically responded to the increase of intracellular SA concentration over a linear range of 19.5 ± 3.6 to 120.9 ± 1.2 fmole at the single-cell level. This new SA biosensor was successfully used to (1) monitor the SA production of different C. glutamicum strains; (2) develop a novel result-oriented high-throughput ribosome binding site screening and sorting strategy that was used for engineering high-yield shikimate-producing strains; and (3) engineer a whole-cell biosensor through the coexpression of the SA sensor and a shikimate transporter shiA gene in C. glutamicum RES167. This work demonstrated that a new intracellular SA biosensor is a valuable tool facilitating the fast development of microbial SA producer.
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Affiliation(s)
- Chang Liu
- State Key Laboratory
of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, West Beichen Road No.1, 100101 Beijing, PR China
- College of Life Sciences, University of Chinese Academy of Sciences, 100049 Beijing, PR China
| | - Bo Zhang
- State Key Laboratory
of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, West Beichen Road No.1, 100101 Beijing, PR China
- Zhejiang University of Technology, 310014 Hangzhou, PR China
| | - Yi-Ming Liu
- State Key Laboratory
of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, West Beichen Road No.1, 100101 Beijing, PR China
| | - Ke-Qian Yang
- State Key Laboratory
of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, West Beichen Road No.1, 100101 Beijing, PR China
| | - Shuang-Jiang Liu
- State Key Laboratory
of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, West Beichen Road No.1, 100101 Beijing, PR China
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Deochand DK, Grove A. MarR family transcription factors: dynamic variations on a common scaffold. Crit Rev Biochem Mol Biol 2017; 52:595-613. [PMID: 28670937 DOI: 10.1080/10409238.2017.1344612] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Members of the multiple antibiotic resistance regulator (MarR) family of transcription factors are critical for bacterial cells to respond to chemical signals and to convert such signals into changes in gene activity. Obligate dimers belonging to the winged helix-turn-helix protein family, they are critical for regulation of a variety of functions, including degradation of organic compounds and control of virulence gene expression. The conventional regulatory paradigm is based on a genomic locus in which the gene encoding the MarR protein is divergently oriented from a gene under its control; MarR binding to the intergenic region controls expression of both genes by changing the interaction of RNA polymerase with gene promoters. MarR protein oxidation or binding of a small molecule ligand adversely affects DNA binding, resulting in altered expression of the divergent genes. The generality of this simple paradigm, including the regulation of Escherichia coli MarR by direct binding of antibiotics, has been challenged by reports published in recent years. In addition, structural and biochemical analyses of ligand binding to numerous MarR homologs are converging to identify a shared ligand-binding "hot-spot". This review highlights recent research advances that point to shared features, yet at the same time highlights the remarkable flexibility with which members of this protein family implement responses to inducing signals. A more comprehensive understanding of protein function will pave the way towards the development of both antibacterial agents and biosensors that are based on MarR family proteins.
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Affiliation(s)
- Dinesh K Deochand
- a Department of Biological Sciences , Louisiana State University , Baton Rouge , LA , USA
| | - Anne Grove
- a Department of Biological Sciences , Louisiana State University , Baton Rouge , LA , USA
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15
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Min BE, Hwang HG, Lim HG, Jung GY. Optimization of industrial microorganisms: recent advances in synthetic dynamic regulators. ACTA ACUST UNITED AC 2017; 44:89-98. [DOI: 10.1007/s10295-016-1867-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 11/04/2016] [Indexed: 12/27/2022]
Abstract
Abstract
Production of biochemicals by industrial fermentation using microorganisms requires maintaining cellular production capacity, because maximal productivity is economically important. High-productivity microbial strains can be developed using static engineering, but these may not maintain maximal productivity throughout the culture period as culture conditions and cell states change dynamically. Additionally, economic reasons limit heterologous protein expression using inducible promoters to prevent metabolic burden for commodity chemical and biofuel production. Recently, synthetic and systems biology has been used to design genetic circuits, precisely controlling gene expression or influencing genetic behavior toward a desired phenotype. Development of dynamic regulators can maintain cellular phenotype in a maximum production state in response to factors including cell concentration, oxygen, temperature, pH, and metabolites. Herein, we introduce dynamic regulators of industrial microorganism optimization and discuss metabolic flux fine control by dynamic regulators in response to metabolites or extracellular stimuli, robust production systems, and auto-induction systems using quorum sensing.
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Affiliation(s)
- Byung Eun Min
- grid.49100.3c 0000000107424007 Department of Chemical Engineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
| | - Hyun Gyu Hwang
- grid.49100.3c 0000000107424007 School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
| | - Hyun Gyu Lim
- grid.49100.3c 0000000107424007 Department of Chemical Engineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
| | - Gyoo Yeol Jung
- grid.49100.3c 0000000107424007 Department of Chemical Engineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
- grid.49100.3c 0000000107424007 School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology 77 Cheongam-ro, Nam-gu 37673 Pohang Gyeongbuk Korea
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Hassan SHA, Van Ginkel SW, Hussein MAM, Abskharon R, Oh SE. Toxicity assessment using different bioassays and microbial biosensors. ENVIRONMENT INTERNATIONAL 2016; 92-93:106-18. [PMID: 27071051 DOI: 10.1016/j.envint.2016.03.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 03/05/2016] [Accepted: 03/05/2016] [Indexed: 05/23/2023]
Abstract
Toxicity assessment of water streams, wastewater, and contaminated sediments, is a very important part of environmental pollution monitoring. Evaluation of biological effects using a rapid, sensitive and cost effective method can indicate specific information on ecotoxicity assessment. Recently, different biological assays for toxicity assessment based on higher and lower organisms such as fish, invertebrates, plants and algal cells, and microbial bioassays have been used. This review focuses on microbial biosensors as an analytical device for environmental, food, and biomedical applications. Different techniques which are commonly used in microbial biosensing include amperometry, potentiometry, conductometry, voltammetry, microbial fuel cells, fluorescence, bioluminescence, and colorimetry. Examples of the use of different microbial biosensors in assessing a variety of environments are summarized.
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Affiliation(s)
- Sedky H A Hassan
- Botany Department, Faculty of Science, Assiut University, New Valley Branch, 72511 Al-Kharja, Egypt
| | - Steven W Van Ginkel
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | | | - Romany Abskharon
- National Institute of Oceanography and Fisheries (NIFO), 11516 Cairo, Egypt
| | - Sang-Eun Oh
- Department of Biological Environment, Kangwon National University, 200-701 Chuncheon, Kangwon-do, South Korea.
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17
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Liu D, Evans T, Zhang F. Applications and advances of metabolite biosensors for metabolic engineering. Metab Eng 2015; 31:35-43. [DOI: 10.1016/j.ymben.2015.06.008] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/23/2015] [Accepted: 06/23/2015] [Indexed: 01/01/2023]
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18
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Sadeghi S, Fooladi E, Malekaneh M. A New Amperometric Benzaldhyde Biosensor Based on Aldehyde Oxidase Immobilized on Fe3O4-GrapheneOxide/Polyvinylpyrrolidone/Polyaniline Nanocomposite. ELECTROANAL 2014. [DOI: 10.1002/elan.201400420] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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19
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Conformational stability and ligand binding properties of BldR, a member of the MarR family, from Sulfolobus solfataricus. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:1167-72. [PMID: 24704039 DOI: 10.1016/j.bbapap.2014.03.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 03/07/2014] [Accepted: 03/26/2014] [Indexed: 12/19/2022]
Abstract
The multiple antibiotic resistance regulators (MarR) constitute a family of ligand-responsive transcriptional regulators ubiquitous among the bacterial and archaeal domains. BldR, an archaeal MarR member characterized from the hyperthermophilic crenarchaeon Sulfolobus solfataricus regulates its own expression and that of an alcohol dehydrogenase gene by binding to sequences in their promoters and responding to benzaldehyde as the effector molecule. In this study we assessed the thermodynamic stability of the protein BldR and its binding with benzaldehyde through biophysical measurements. The temperature- and denaturant-induced unfolding experiments, performed by means of circular dichroism (CD) and differential scanning calorimetry (DSC), showed that BldR has an extremely high thermal stability (Td=108.9°C) and a remarkable resistance against GuHCl (Cm=5.3M at 25°C). The unfolding Gibbs energy, ΔdG (H2O), calculated by the linear extrapolation model from GuHCl-induced unfolding equilibrium curve, is 72.2kJmol(-1). ITC binding experiments showed that four benzaldehyde molecules bind to one BldR dimer with a binding constant Kb of 7.5·10(5)M(-1), being the binding entropically driven. ITC, CD and fluorescence results are consistent with a conformational change induced by benzaldehyde binding, further proving that this molecule is a specific effector for BldR modulating its DNA binding activity.
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20
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Molecular biology of fuselloviruses and their satellites. Extremophiles 2014; 18:473-89. [DOI: 10.1007/s00792-014-0634-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 01/31/2014] [Indexed: 10/25/2022]
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21
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Contursi P, Fusco S, Limauro D, Fiorentino G. Host and viral transcriptional regulators in Sulfolobus: an overview. Extremophiles 2013; 17:881-95. [PMID: 24085522 DOI: 10.1007/s00792-013-0586-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 09/16/2013] [Indexed: 12/29/2022]
Abstract
The genus Sulfolobus includes microorganisms belonging to the domain Archaea, sub-kingdom Crenarchaeota, living in geographically distant acidic hot springs. Their adaptation to such particular habitats requires finely regulated mechanisms of gene expression, among which, those modulated by sequence-specific transcription factors (TFs) play a key role. In this review, we summarize the current knowledge on the repertoires of TFs found in Sulfolobus spp. and their viruses, focusing on the description of their DNA-binding domains and their structure-function relationship.
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Affiliation(s)
- Patrizia Contursi
- Dipartimento di Biologia, Università di Napoli Federico II, via Cinthia, Edificio 7, 80126, Napoli, Italy
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22
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de Las Heras A, de Lorenzo V. Engineering whole-cell biosensors with no antibiotic markers for monitoring aromatic compounds in the environment. Methods Mol Biol 2012; 834:261-81. [PMID: 22144365 DOI: 10.1007/978-1-61779-483-4_17] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
A cornerstone of Synthetic Biology is the engineering of gene regulatory networks. Construction of such biological circuits has been used not only to elucidate the dynamics of gene expression but also for designing whole-cell biosensors that translate environmental signals into quantifiable outputs. To this end, distinct components of given regulatory systems are rationally rewired in a way that translates an external stimulus (for instance, the presence of one chemical species) into a measurable readout typically fluorescence or luminescence. Various biosensors for BTEX (a mixture of benzene, toluene, ethylbenzene and xylenes) are based on XylR, the main transcriptional regulator of the TOL pathway of Pseudomonas putida mt-2. In the presence of its natural effectors (e.g., m-xylene, toluene or 3-methylbenzylalcohol), XylR triggers expression of the upper pathway genes by means of the Pu promoter. Available biosensors combine the xylR gene and a direct fusion between the cognate Pu promoter and the luxCDABE operon, all components stably integrated in the chromosome of P. putida. A versatile development of the same biosensing concept is described, aimed at increasing the sensitivity of the genetic circuit toward XylR inducers. The new platform utilizes mini-transposon vectors tailored for engineering an artificial expression cascade that operates as an amplifier of the signal/response ratio of the biosensor. This strategy was applied to the construction of a strain that carries a transcriptional fusion between the Pu promoter and T7 RNA polymerase (which becomes under the control of XylR and its effectors), along with a T7 promoter controlling expression of the luxCDABE operon. This simple regulatory architecture produced a dramatic increase of bioluminescence emission in respect to the strain that carries only the direct fusion between the Pu promoter and the luxCDABE reporter.
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Affiliation(s)
- Aitor de Las Heras
- Centro Nacional de Biotecnología-CSIC, Campus de Cantoblanco, Madrid, Spain
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23
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Fiorentino G, Del Giudice I, Bartolucci S, Durante L, Martino L, Del Vecchio P. Identification and Physicochemical Characterization of BldR2 from Sulfolobus solfataricus, a Novel Archaeal Member of the MarR Transcription Factor Family. Biochemistry 2011; 50:6607-21. [DOI: 10.1021/bi200187j] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gabriella Fiorentino
- Department of Structural and Functional Biology, University of Naples Federico II, Edificio 7, via Cinthia, 80126 Naples, Italy
| | - Immacolata Del Giudice
- Department of Structural and Functional Biology, University of Naples Federico II, Edificio 7, via Cinthia, 80126 Naples, Italy
| | - Simonetta Bartolucci
- Department of Structural and Functional Biology, University of Naples Federico II, Edificio 7, via Cinthia, 80126 Naples, Italy
| | - Lorenzo Durante
- Department of Chemistry “Paolo Corradini”, University of Naples Federico II, via Cinthia, 80126 Naples, Italy
| | - Luigi Martino
- Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, U.K
| | - Pompea Del Vecchio
- Department of Chemistry “Paolo Corradini”, University of Naples Federico II, via Cinthia, 80126 Naples, Italy
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24
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Pasco NF, Weld RJ, Hay JM, Gooneratne R. Development and applications of whole cell biosensors for ecotoxicity testing. Anal Bioanal Chem 2011; 400:931-45. [DOI: 10.1007/s00216-011-4663-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 12/22/2010] [Accepted: 01/03/2011] [Indexed: 10/18/2022]
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25
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Su L, Jia W, Hou C, Lei Y. Microbial biosensors: A review. Biosens Bioelectron 2011; 26:1788-99. [DOI: 10.1016/j.bios.2010.09.005] [Citation(s) in RCA: 325] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 08/29/2010] [Accepted: 09/02/2010] [Indexed: 02/01/2023]
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26
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Fluorescent Proteins as a Visible Molecular Signal for Rapid Quantification of Bioprocesses: Potential and Challenges. Chin J Chem Eng 2010. [DOI: 10.1016/s1004-9541(09)60140-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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27
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Chalova VI, Froelich CA, Ricke SC. Potential for development of an Escherichia coli-based biosensor for assessing bioavailable methionine: a review. SENSORS (BASEL, SWITZERLAND) 2010; 10:3562-84. [PMID: 22319312 PMCID: PMC3274233 DOI: 10.3390/s100403562] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Revised: 03/11/2010] [Accepted: 03/26/2010] [Indexed: 11/30/2022]
Abstract
Methionine is an essential amino acid for animals and is typically considered one of the first limiting amino acids in animal feed formulations. Methionine deficiency or excess in animal diets can lead to sub-optimal animal performance and increased environmental pollution, which necessitates its accurate quantification and proper dosage in animal rations. Animal bioassays are the current industry standard to quantify methionine bioavailability. However, animal-based assays are not only time consuming, but expensive and are becoming more scrutinized by governmental regulations. In addition, a variety of artifacts can hinder the variability and time efficacy of these assays. Microbiological assays, which are based on a microbial response to external supplementation of a particular nutrient such as methionine, appear to be attractive potential alternatives to the already established standards. They are rapid and inexpensive in vitro assays which are characterized with relatively accurate and consistent estimation of digestible methionine in feeds and feed ingredients. The current review discusses the potential to develop Escherichia coli-based microbial biosensors for methionine bioavailability quantification. Methionine biosynthesis and regulation pathways are overviewed in relation to genetic manipulation required for the generation of a respective methionine auxotroph that could be practical for a routine bioassay. A prospective utilization of Escherichia coli methionine biosensor would allow for inexpensive and rapid methionine quantification and ultimately enable timely assessment of nutritional profiles of feedstuffs.
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Affiliation(s)
- Vesela I. Chalova
- Poultry Science Department, Texas A&M University, College Station, TX 77843-2472, USA; E-Mails: (V.I.C.); (C.A.F.)
- Center for Food Safety and Department of Food Science, University of Arkansas, Fayetteville, AR 72704, USA
| | - Clifford A. Froelich
- Poultry Science Department, Texas A&M University, College Station, TX 77843-2472, USA; E-Mails: (V.I.C.); (C.A.F.)
| | - Steven C. Ricke
- Poultry Science Department, Texas A&M University, College Station, TX 77843-2472, USA; E-Mails: (V.I.C.); (C.A.F.)
- Center for Food Safety and Department of Food Science, University of Arkansas, Fayetteville, AR 72704, USA
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28
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Liu X, Germaine KJ, Ryan D, Dowling DN. Whole-cell fluorescent biosensors for bioavailability and biodegradation of polychlorinated biphenyls. SENSORS 2010; 10:1377-98. [PMID: 22205873 PMCID: PMC3244019 DOI: 10.3390/s100201377] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 01/14/2010] [Accepted: 01/29/2010] [Indexed: 11/30/2022]
Abstract
Whole-cell microbial biosensors are one of the newest molecular tools used in environmental monitoring. Such biosensors are constructed through fusing a reporter gene such as lux, gfp or lacZ, to a responsive promoter. There have been many reports of the applications of biosensors, particularly their use in assaying pollutant toxicity and bioavailability. This paper reviews the basic concepts behind the construction of whole-cell microbial biosensors for pollutant monitoring, and describes the applications of two such biosensors for detecting the bioavailability and biodegradation of Polychlorinated Biphenyls (PCBs).
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Affiliation(s)
- Xuemei Liu
- Department of Science and Health, Institute of Technology Carlow, Kilkenny Road, Carlow, Ireland.
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