1
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Pham C, Stogios PJ, Savchenko A, Mahadevan R. Advances in engineering and optimization of transcription factor-based biosensors for plug-and-play small molecule detection. Curr Opin Biotechnol 2022; 76:102753. [PMID: 35872379 DOI: 10.1016/j.copbio.2022.102753] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/31/2022] [Accepted: 06/06/2022] [Indexed: 11/30/2022]
Abstract
Transcription factor (TF)-based biosensors have been applied in biotechnology for a variety of functions, including protein engineering, dynamic control, environmental detection, and point-of-care diagnostics. Such biosensors are promising analytical tools due to their wide range of detectable ligands and modular nature. However, designing biosensors tailored for applications of interest with the desired performance parameters, including ligand specificity, remains challenging. Biosensors often require significant engineering and tuning to meet desired specificity, sensitivity, dynamic range, and operating range parameters. Another limitation is the orthogonality of biosensors across hosts, given the role of the cellular context. Here, we describe recent advances and examples in the engineering and optimization of TF-based biosensors for plug-and-play small molecule detection. We highlight novel developments in TF discovery and biosensor design, TF specificity engineering, and biosensor tuning, with emphasis on emerging computational methods.
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Affiliation(s)
- Chester Pham
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, ON, Canada
| | - Peter J Stogios
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, ON, Canada
| | - Alexei Savchenko
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, ON, Canada; Department of Microbiology, Immunology and Infectious Disease, University of Calgary, AB, Canada
| | - Radhakrishnan Mahadevan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, ON, Canada; The Institute of Biomedical Engineering, University of Toronto, ON, Canada.
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2
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Liu J, Liu Y, Dong W, Li J, Yu S, Wang J, Zuo R. Shifts in microbial community structure and function in polycyclic aromatic hydrocarbon contaminated soils at petrochemical landfill sites revealed by metagenomics. CHEMOSPHERE 2022; 293:133509. [PMID: 34995620 DOI: 10.1016/j.chemosphere.2021.133509] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 12/26/2021] [Accepted: 12/31/2021] [Indexed: 06/14/2023]
Abstract
Investigations of the microbial community structures, potential functions and polycyclic aromatic hydrocarbon (PAH) degradation-related genes in PAH-polluted soils are useful for risk assessments, microbial monitoring, and the potential bioremediation of soils polluted by PAHs. In this study, five soil sampling sites were selected at a petrochemical landfill in Beijing, China, to analyze the contamination characteristics of PAHs and their impact on microorganisms. The concentrations of 16 PAHs were detected by gas chromatography-mass spectrometry. The total concentrations of the PAHs ranged from ND to 3166.52 μg/kg, while phenanthrene, pyrene, fluoranthene and benzo [ghi]perylene were the main components in the soil samples. According to the specific PAH ratios, the PAHs mostly originated from petrochemical wastes in the landfill. The levels of the total toxic benzo [a]pyrene equivalent (1.63-107.73 μg/kg) suggested that PAHs might result in adverse effects on soil ecosystems. The metagenomic analysis showed that the most abundant phyla in the soils were Proteobacteria and Actinobacteria, and Solirubrobacter was the most important genus. At the genus level, Bradyrhizobium, Mycobacterium and Anaeromyxobacter significantly increased under PAH stress. Based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations, the most abundant category of functions that are involved in adapting to contaminant pressures was identified. Ten PAH degradation-related genes were significantly influenced by PAH pressure and showed correlations with PAH concentrations. All of the results suggested that the PAHs from the petrochemical landfill could be harmful to soil environments and impact the soil microbial community structures, while microorganisms would change their physiological functions to resist pollutant stress.
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Affiliation(s)
- Jiayou Liu
- Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, College of Water Sciences, Beijing Normal University, Beijing, 100875, China
| | - Yun Liu
- South China Institute of Environmental Sciences, Ministry of Environmental Protection of the People's Republic of China, State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, Guangzhou, 510655, China
| | - Weihong Dong
- Key Laboratory of Groundwater Resources and Environments, Ministry of Education, Jilin University, Changchun, Jilin, 130021, China; Institute of Water Resources and Environment, Jilin University, Changchun, Jilin, 130021, China
| | - Jian Li
- Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, College of Water Sciences, Beijing Normal University, Beijing, 100875, China.
| | - Shihang Yu
- Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, College of Water Sciences, Beijing Normal University, Beijing, 100875, China
| | - Jinsheng Wang
- Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, College of Water Sciences, Beijing Normal University, Beijing, 100875, China
| | - Rui Zuo
- Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, College of Water Sciences, Beijing Normal University, Beijing, 100875, China
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Wakamatsu T, Mizobuchi S, Mori F, Futagami T, Terada T, Morono Y. Construction of Aerobic/Anaerobic-Substrate-Induced Gene Expression Procedure for Exploration of Metagenomes From Subseafloor Sediments. Front Microbiol 2022; 12:726024. [PMID: 35095779 PMCID: PMC8793675 DOI: 10.3389/fmicb.2021.726024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 12/17/2021] [Indexed: 11/13/2022] Open
Abstract
Substrate-induced gene expression (SIGEX) is a high-throughput promoter-trap method. It is a function-based metagenomic screening tool that relies on transcriptional activation of a reporter gene green fluorescence protein (gfp) by a metagenomic DNA library upon induction with a substrate. However, its use is limited because of the relatively small size of metagenomic DNA libraries and incompatibility with screening metagenomes from anaerobic environments. In this study, these limitations of SIGEX were addressed by fine-tuning metagenome DNA library construction protocol and by using Evoglow, a green fluorescent protein that forms a chromophore even under anaerobic conditions. Two metagenomic libraries were constructed for subseafloor sediments offshore Shimokita Peninsula (Pacific Ocean) and offshore Joetsu (Japan Sea). The library construction protocol was improved by (a) eliminating short DNA fragments, (b) applying topoisomerase-based high-efficiency ligation, (c) optimizing insert DNA concentration, and (d) column-based DNA enrichment. This led to a successful construction of metagenome DNA libraries of approximately 6 Gbp for both samples. SIGEX screening using five aromatic compounds (benzoate, 3-chlorobenzoate, 3-hydroxybenzoate, phenol, and 2,4-dichlorophenol) under aerobic and anaerobic conditions revealed significant differences in the inducible clone ratios under these conditions. 3-Chlorobenzoate and 2,4-dichlorophenol led to a higher induction ratio than that for the other non-chlorinated aromatic compounds under both aerobic and anaerobic conditions. After the further screening of induced clones, a clone induced by 3-chlorobenzoate only under anaerobic conditions was isolated and characterized. The clone harbors a DNA insert that encodes putative open reading frames of unknown function. Previous aerobic SIGEX attempts succeeded in the isolation of gene fragments from anaerobes. This study demonstrated that some gene fragments require a strict in vivo reducing environment to function and may be potentially missed when screened by aerobic induction. The newly developed anaerobic SIGEX scheme will facilitate functional exploration of metagenomes from the anaerobic biosphere.
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Affiliation(s)
- Taisuke Wakamatsu
- Agricultural Sciences, Graduate School of Integrated Arts and Sciences, Kochi University, Kōchi, Japan
| | - Saki Mizobuchi
- Agricultural Sciences, Graduate School of Integrated Arts and Sciences, Kochi University, Kōchi, Japan
| | - Fumiaki Mori
- Geomicrobiology Group, Kochi Institute for Core Smaple Research, Japan Agency for Marine-Earth Science and Technology, Kōchi, Japan
| | - Taiki Futagami
- Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima, Japan
| | | | - Yuki Morono
- Geomicrobiology Group, Kochi Institute for Core Smaple Research, Japan Agency for Marine-Earth Science and Technology, Kōchi, Japan
- *Correspondence: Yuki Morono,
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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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5
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Terashima M, Kamagata Y, Kato S. Rapid Enrichment and Isolation of Polyphosphate-Accumulating Organisms Through 4'6-Diamidino-2-Phenylindole (DAPI) Staining With Fluorescence-Activated Cell Sorting (FACS). Front Microbiol 2020; 11:793. [PMID: 32425914 PMCID: PMC7203516 DOI: 10.3389/fmicb.2020.00793] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 04/02/2020] [Indexed: 12/13/2022] Open
Abstract
Screening for bacteria with abilities to accumulate valuable intracellular compounds from an environmental community is difficult and requires strategic methods. Combining the experimental procedure for phenotyping living cells in a microbial community with the cell recovery necessary for further cultivation will allow for an efficient initial screening process. In this study, we developed a strategy for the isolation of polyphosphate-accumulating organisms (PAOs) by combining (i) nontoxic fluorescence staining of polyphosphate granules in viable microbial cells and (ii) fluorescence-activated cell sorting (FACS) for the rapid detection and collection of target cells. To implement this screening approach, cells from wastewater sludge samples were stained with 4’6-diamidino-2-phenylindole (DAPI) to target cells with high polyphosphate (polyP) accumulation. We found a staining procedure (10 μg/ml of DAPI for 30 min) that can visualize polyP granules while maintaining viability for the majority of the cells (>60%). The polyP positive cells were recovered by FACS, purified by colony isolation and phylogenetically identified by 16S rRNA gene sequencing. Follow-up analysis confirmed that these isolates accumulate polyP, indicating that DAPI can be implemented in staining living cells and FACS can effectively and rapidly screen and isolate individual cells from a complex microbial community.
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Affiliation(s)
- Mia Terashima
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan.,Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Yoichi Kamagata
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan.,Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan.,Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Souichiro Kato
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan.,Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
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6
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Markel U, Essani KD, Besirlioglu V, Schiffels J, Streit WR, Schwaneberg U. Advances in ultrahigh-throughput screening for directed enzyme evolution. Chem Soc Rev 2020; 49:233-262. [PMID: 31815263 DOI: 10.1039/c8cs00981c] [Citation(s) in RCA: 142] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Enzymes are versatile catalysts and their synthetic potential has been recognized for a long time. In order to exploit their full potential, enzymes often need to be re-engineered or optimized for a given application. (Semi-) rational design has emerged as a powerful means to engineer proteins, but requires detailed knowledge about structure function relationships. In turn, directed evolution methodologies, which consist of iterative rounds of diversity generation and screening, can improve an enzyme's properties with virtually no structural knowledge. Current diversity generation methods grant us access to a vast sequence space (libraries of >1012 enzyme variants) that may hide yet unexplored catalytic activities and selectivity. However, the time investment for conventional agar plate or microtiter plate-based screening assays represents a major bottleneck in directed evolution and limits the improvements that are obtainable in reasonable time. Ultrahigh-throughput screening (uHTS) methods dramatically increase the number of screening events per time, which is crucial to speed up biocatalyst design, and to widen our knowledge about sequence function relationships. In this review, we summarize recent advances in uHTS for directed enzyme evolution. We shed light on the importance of compartmentalization to preserve the essential link between genotype and phenotype and discuss how cells and biomimetic compartments can be applied to serve this function. Finally, we discuss how uHTS can inspire novel functional metagenomics approaches to identify natural biocatalysts for novel chemical transformations.
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Affiliation(s)
- Ulrich Markel
- Institute of Biotechnology, RWTH Aachen University, Worringer Weg 3, 52074 Aachen, Germany.
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Prabha R, Singh DP, Gupta S, Gupta VK, El-Enshasy HA, Verma MK. Rhizosphere Metagenomics of Paspalum scrobiculatum L. (Kodo Millet) Reveals Rhizobiome Multifunctionalities. Microorganisms 2019; 7:microorganisms7120608. [PMID: 31771141 PMCID: PMC6956225 DOI: 10.3390/microorganisms7120608] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 10/15/2019] [Indexed: 12/23/2022] Open
Abstract
Multifunctionalities linked with the microbial communities associated with the millet crop rhizosphere has remained unexplored. In this study, we are analyzing microbial communities inhabiting rhizosphere of kodo millet and their associated functions and its impact over plant growth and survival. Metagenomics of Paspalum scrobiculatum L.(kodo millet) rhizopshere revealed taxonomic communities with functional capabilities linked to support growth and development of the plants under nutrient-deprived, semi-arid and dry biotic conditions. Among 65 taxonomically diverse phyla identified in the rhizobiome, Actinobacteria were the most abundant followed by the Proteobacteria. Functions identified for different genes/proteins led to revelations that multifunctional rhizobiome performs several metabolic functions including carbon fixation, nitrogen, phosphorus, sulfur, iron and aromatic compound metabolism, stress response, secondary metabolite synthesis and virulence, disease, and defense. Abundance of genes linked with N, P, S, Fe and aromatic compound metabolism and phytohormone synthesis—along with other prominent functions—clearly justifies growth, development, and survival of the plants under nutrient deprived dry environment conditions. The dominance of actinobacteria, the known antibiotic producing communities shows that the kodo rhizobiome possesses metabolic capabilities to defend themselves against biotic stresses. The study opens avenues to revisit multi-functionalities of the crop rhizosphere for establishing link between taxonomic abundance and targeted functions that help plant growth and development in stressed and nutrient deprived soil conditions. It further helps in understanding the role of rhizosphere microbiome in adaptation and survival of plants in harsh abiotic conditions.
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Affiliation(s)
- Ratna Prabha
- Chhattisgarh Swami Vivekananda Technical University, Bhilai, Chhattisgarh 491107, India; (R.P.); (M.K.V.)
| | - Dhananjaya P. Singh
- ICAR-National Bureau of Agriculturally Important Microorganisms, Indian Council of Agricultural Research, Kushmaur, Maunath Bhanjan 275101, UP, India
- Correspondence:
| | - Shailendra Gupta
- Department of Systems Biology and Bioinformatics, University of Rostock, Rostock 18057, Germany;
| | - Vijai Kumar Gupta
- Department of Chemistry and Biotechnology, ERA Chair of Green Chemistry, Tallinn University of Technology, 12618 Tallinn, Estonia;
| | - Hesham A. El-Enshasy
- Institute of Bioproduct Development, Universiti Teknologi Malaysia, Skudai 81310, Johor Bahru, Johor, Malaysia;
| | - Mukesh K. Verma
- Chhattisgarh Swami Vivekananda Technical University, Bhilai, Chhattisgarh 491107, India; (R.P.); (M.K.V.)
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8
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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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9
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Ngara TR, Zhang H. Recent Advances in Function-based Metagenomic Screening. GENOMICS PROTEOMICS & BIOINFORMATICS 2018; 16:405-415. [PMID: 30597257 PMCID: PMC6411959 DOI: 10.1016/j.gpb.2018.01.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/05/2018] [Accepted: 01/09/2018] [Indexed: 12/01/2022]
Abstract
Metagenomes from uncultured microorganisms are rich resources for novel enzyme genes. The methods used to screen the metagenomic libraries fall into two categories, which are based on sequence or function of the enzymes. The sequence-based approaches rely on the known sequences of the target gene families. In contrast, the function-based approaches do not involve the incorporation of metagenomic sequencing data and, therefore, may lead to the discovery of novel gene sequences with desired functions. In this review, we discuss the function-based screening strategies that have been used in the identification of enzymes from metagenomes. Because of its simplicity, agar plate screening is most commonly used in the identification of novel enzymes with diverse functions. Other screening methods with higher sensitivity are also employed, such as microtiter plate screening. Furthermore, several ultra-high-throughput methods were developed to deal with large metagenomic libraries. Among these are the FACS-based screening, droplet-based screening, and the in vivo reporter-based screening methods. The application of these novel screening strategies has increased the chance for the discovery of novel enzyme genes.
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Affiliation(s)
- Tanyaradzwa Rodgers Ngara
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, MOE Key Laboratory of Molecular Biophysics, Wuhan 430074, China
| | - Houjin Zhang
- Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, MOE Key Laboratory of Molecular Biophysics, Wuhan 430074, China.
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10
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Wakamatsu T, Morono Y, Futagami T, Terada T, Nishikawa S, Morisawa T, Ohshita K, Inagaki F, Ashiuchi M. Metal-ion-induced expression of gene fragments from subseafloor micro-organisms in the Kumano forearc basin, Nankai Trough. J Appl Microbiol 2018; 125:1396-1407. [PMID: 30080957 DOI: 10.1111/jam.14061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 06/30/2018] [Accepted: 07/23/2018] [Indexed: 12/30/2022]
Abstract
AIMS Using substrate-induced gene-expression (SIGEX) screening on subseafloor sediment samples from the Nankai Trough, Japan, we identified gene fragments showing an induction response to metal ions. METHODS AND RESULTS Environmental DNA libraries in Escherichia coli host cells were tested by the addition of metal ions (Ni2+ , Co2+ , Ga3+ or Mo6+ ), followed by cell sorting of clones exhibiting green fluorescence upon co-expression of green fluorescence protein downstream of the inserted gene fragments. One clone displayed Ni2+ -specific induction, three clones displayed Ga3+ -specific induction and three clones displayed an induction response to multiple metal ions. DNA sequence analysis showed that a variety of genes showed induction responses in the screened clones. CONCLUSIONS Using the SIGEX approach, we retrieved gene fragments with no previously identified response to metal ions that exhibited metal-ion-induced expression. This method has the potential to promote exploration of gene function through gene-induction response. SIGNIFICANCE AND IMPACT OF THE STUDY We successfully linked gene-induction response with sequence information for gene fragments of previously unknown function. The SIGEX-based approach exhibited the potential to identify genetic function in unknown gene pools from the deep subseafloor biosphere, as well as novel genetic components for future biotechnological applications.
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Affiliation(s)
- T Wakamatsu
- Agricultural Science, Graduate School of Integrated Arts and Sciences, Kochi University, Kochi, Japan
| | - Y Morono
- Geomicrobiology Group, Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Kochi, Japan.,Geobiotechnology Group, Research and Development Center for Submarine Resources, JAMSTEC, Kanagawa, Japan
| | - T Futagami
- Education and Research Center for Fermentation Studies, Faculty of Agriculture, Kagoshima University, Kagoshima, Japan
| | - T Terada
- Marine Works Japan Ltd, Kanagawa, Japan
| | - S Nishikawa
- Agricultural Science, Graduate School of Integrated Arts and Sciences, Kochi University, Kochi, Japan
| | - T Morisawa
- Agricultural Science, Graduate School of Integrated Arts and Sciences, Kochi University, Kochi, Japan
| | - K Ohshita
- Agricultural Science, Graduate School of Integrated Arts and Sciences, Kochi University, Kochi, Japan
| | - F Inagaki
- Geomicrobiology Group, Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Kochi, Japan.,Geobiotechnology Group, Research and Development Center for Submarine Resources, JAMSTEC, Kanagawa, Japan.,Research and Development Center for Ocean Drilling Science, Kanagawa, Japan
| | - M Ashiuchi
- Agricultural Science, Graduate School of Integrated Arts and Sciences, Kochi University, Kochi, Japan
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11
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The evolving interface between synthetic biology and functional metagenomics. Nat Chem Biol 2018; 14:752-759. [DOI: 10.1038/s41589-018-0100-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 06/13/2018] [Indexed: 12/15/2022]
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12
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Singh DP, Prabha R, Gupta VK, Verma MK. Metatranscriptome Analysis Deciphers Multifunctional Genes and Enzymes Linked With the Degradation of Aromatic Compounds and Pesticides in the Wheat Rhizosphere. Front Microbiol 2018; 9:1331. [PMID: 30034370 PMCID: PMC6043799 DOI: 10.3389/fmicb.2018.01331] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 05/31/2018] [Indexed: 11/19/2022] Open
Abstract
Agricultural soils are becoming contaminated with synthetic chemicals like polyaromatic compounds, petroleum hydrocarbons, polychlorinated biphenyls (PCBs), phenols, herbicides, insecticides and fungicides due to excessive dependency of crop production systems on the chemical inputs. Microbial degradation of organic pollutants in the agricultural soils is a continuous process due to the metabolic multifunctionalities and enzymatic capabilities of the soil associated communities. The plant rhizosphere with its complex microbial inhabitants and their multiple functions, is amongst the most live and dynamic component of agricultural soils. We analyzed the metatranscriptome data of 20 wheat rhizosphere samples to decipher the taxonomic microbial communities and their multifunctionalities linked with the degradation of organic soil contaminants. The analysis revealed a total of 21 different metabolic pathways for the degradation of aromatic compounds and 06 for the xenobiotics degradation. Taxonomic annotation of wheat rhizosphere revealed bacteria, especially the Proteobacteria, actinobacteria, firmicutes, bacteroidetes, and cyanobacteria, which are shown to be linked with the degradation of aromatic compounds as the dominant communities. Abundance of the transcripts related to the degradation of aromatic amin compounds, carbazoles, benzoates, naphthalene, ketoadipate pathway, phenols, biphenyls and xenobiotics indicated abundant degradation capabilities in the soils. The results highlighted a potentially dominant role of crop rhizosphere associated microbial communities in the remediation of contaminant aromatic compounds.
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Affiliation(s)
- Dhananjaya P. Singh
- ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan, India
| | - Ratna Prabha
- Department of Bio-Medical Engineering and Bio-Informatics, Chhattisgarh Swami Vivekanand Technical University, Bhilai, India
| | - Vijai K. Gupta
- ERA Chair of Green Chemistry, Department of Chemistry and Biotechnology, School of Science, Tallinn University of Technology, Tallinn, Estonia
| | - Mukesh K. Verma
- Department of Bio-Medical Engineering and Bio-Informatics, Chhattisgarh Swami Vivekanand Technical University, Bhilai, India
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13
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Miyazaki K. Molecular engineering of the salicylate-inducible transcription factor Sal7AR for orthogonal and high gene expression in Escherichia coli. PLoS One 2018; 13:e0194090. [PMID: 29641575 PMCID: PMC5894983 DOI: 10.1371/journal.pone.0194090] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 02/25/2018] [Indexed: 11/18/2022] Open
Abstract
I have previously identified a metagenomic fragment (~4 kb) containing the salicylate (2-hydroxybenzoate)-responsive transcriptional regulator Sal7AR. Taking advantage of the inert nature of salicylate to common genetic switches used in Escherichia coli, here I developed a salicylate-inducible high expression system in E. coli. I first applied a deletion analysis to the metagenomic fragment to identify the core region (~1 kb) necessary for the salicylate-dependent expression. Sal7AR was subjected to an error-prone PCR, and a library was screened for an enhanced expression of a reporter green fluorescent protein (GFP) gene in the presence of 1 mM salicylate, where virtually no growth inhibition was observed. Three beneficial amino acid substitutions were identified (N282K, Q292R, and V295G), each of which improved the expression of GFP relative to the wildtype by several-fold. The three sites were then completely randomized by saturation mutagenesis either individually or combinatorially to identify three variants carrying a single point mutation, N282L, V295F, or V295S; no further improvements were observed by combining these mutations. Salicylate-dependent expression of these mutants was highly repressed in its absence and escalated in response to ~10 μM salicylate, and gradually increased up to 1 mM salicylate; the induction rate was approximately 15 times greater than that achieved with a lactose promoter. Orthogonality to the lactose-based expression system was also confirmed. This salicylate-based expression system should thus be advantageously used for high-level production of recombinant proteins in combination with common lactose-dependent induction systems.
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Affiliation(s)
- Kentaro Miyazaki
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan
- * E-mail:
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Zafra G, Taylor TD, Absalón AE, Cortés-Espinosa DV. Comparative metagenomic analysis of PAH degradation in soil by a mixed microbial consortium. JOURNAL OF HAZARDOUS MATERIALS 2016; 318:702-710. [PMID: 27484946 DOI: 10.1016/j.jhazmat.2016.07.060] [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: 03/28/2016] [Revised: 06/29/2016] [Accepted: 07/25/2016] [Indexed: 05/02/2023]
Abstract
In this study, we used a taxonomic and functional metagenomic approach to analyze some of the effects (e.g. displacement, permanence, disappearance) produced between native microbiota and a previously constructed Polycyclic Aromatic Hydrocarbon (PAH)-degrading microbial consortium during the bioremediation process of a soil polluted with PAHs. Bioaugmentation with a fungal-bacterial consortium and biostimulation of native microbiota using corn stover as texturizer produced appreciable changes in the microbial diversity of polluted soils, shifting native microbial communities in favor of degrading specific populations. Functional metagenomics showed changes in gene abundance suggesting a bias towards aromatic hydrocarbon and intermediary degradation pathways, which greatly favored PAH mineralization. In contrast, pathways favoring the formation of toxic intermediates such as cytochrome P450-mediated reactions were found to be significantly reduced in bioaugmented soils. PAH biodegradation in soil using the microbial consortium was faster and reached higher degradation values (84% after 30 d) as a result of an increased co-metabolic degradation when compared with other mixed microbial consortia. The main differences between inoculated and non-inoculated soils were observed in aromatic ring-hydroxylating dioxygenases, laccase, protocatechuate, salicylate and benzoate-degrading enzyme genes. Based on our results, we propose that several concurrent metabolic pathways are taking place in soils during PAH degradation.
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Affiliation(s)
- German Zafra
- Instituto Politécnico Nacional, CIBA-Tlaxcala, Carretera Estatal San Inés Tecuexcomac-Tepetitla Km 1.5, Tepetitla, Tlaxcala. 90700, Mexico
| | - Todd D Taylor
- RIKEN Center for Integrative Medical Sciences, Laboratory for Integrated Bioinformatics, Tsurumi-ku 230-0045, Yokohama, Kanagawa, Japan
| | - Angel E Absalón
- Instituto Politécnico Nacional, CIBA-Tlaxcala, Carretera Estatal San Inés Tecuexcomac-Tepetitla Km 1.5, Tepetitla, Tlaxcala. 90700, Mexico.
| | - Diana V Cortés-Espinosa
- Instituto Politécnico Nacional, CIBA-Tlaxcala, Carretera Estatal San Inés Tecuexcomac-Tepetitla Km 1.5, Tepetitla, Tlaxcala. 90700, Mexico.
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Libis V, Delépine B, Faulon JL. Sensing new chemicals with bacterial transcription factors. Curr Opin Microbiol 2016; 33:105-112. [PMID: 27472026 DOI: 10.1016/j.mib.2016.07.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 06/15/2016] [Accepted: 07/06/2016] [Indexed: 11/30/2022]
Abstract
Bacteria rely on allosteric transcription factors (aTFs) to sense a wide range of chemicals. The variety of effectors has contributed in making aTFs the most used input system in synthetic biological circuits. Considering their enabling role in biotechnology, an important question concerns the size of the chemical space that can potentially be detected by these biosensors. From digging into the ever changing repertoire of natural regulatory circuits, to advances in aTF engineering, we review here different strategies that are pushing the boundaries of this chemical space. We also review natural and synthetic cases of indirect sensing, where aTFs work in combination with metabolism to enable detection of new molecules.
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Affiliation(s)
- Vincent Libis
- iSSB, Genopole, CNRS, UEVE, Université Paris Saclay, 91000 Évry, France; Micalis Institute, INRA, AgroParisTech, Université Paris Saclay, 78350 Jouy-en-Josas, France
| | - Baudoin Delépine
- iSSB, Genopole, CNRS, UEVE, Université Paris Saclay, 91000 Évry, France; Micalis Institute, INRA, AgroParisTech, Université Paris Saclay, 78350 Jouy-en-Josas, France
| | - Jean-Loup Faulon
- iSSB, Genopole, CNRS, UEVE, Université Paris Saclay, 91000 Évry, France; Micalis Institute, INRA, AgroParisTech, Université Paris Saclay, 78350 Jouy-en-Josas, France; SYNBIOCHEM Centre, Manchester Institute of Biotechnology, University of Manchester, Manchester, UK.
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