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Du J, Li Y, Chen Z, Wang C, Huang Y, Li L. Functional characterization of a novel flavin reductase from a deep-sea sediment metagenomic library and its application for indirubin production. Appl Environ Microbiol 2024; 90:e0042924. [PMID: 38780258 PMCID: PMC11218617 DOI: 10.1128/aem.00429-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 04/30/2024] [Indexed: 05/25/2024] Open
Abstract
Microbial synthesis is a desirable approach to produce indirubin but suffers from low synthetic efficiency. Insufficient supply of reduced flavins is one major factor limiting synthetic efficiency. To address this, a novel flavin reductase, MoxB, was discovered through screening of the metagenomic library. MoxB showed a strong preference for NADH over NADPH as the electron source for FMN/FAD reduction and exhibited the highest activity at pH 8.0 and 30°C. It displayed remarkable thermostability by maintaining 80% of full activity after incubation at 60°C for 1 h. Furthermore, MoxB showed great organic solvent tolerance and its activity could be significantly increased by bivalent metal ions. In addition, heterologous expression of the moxB gene in the indirubin-producing E. coli significantly improved indirubin production up to 15.12-fold. This discovery expands the understanding of flavin reductases and provides a promising catalytic tool for microbial indirubin production.IMPORTANCEMuch effort has been exerted to produce indirubin using engineered Escherichia coli, but high-level production has not been achieved so far. Insufficient supply of reduced flavins is one key factor limiting the catalytic efficiency. However, the flavin reductases involved in indirubin biosynthesis have not been hitherto reported. Discovery of the novel flavin reductase MoxB provides a useful tool for enhancing indirubin production by E. coli. Overexpression of MoxB in indirubin-producing E. coli increased indirubin production by 15.12-fold in comparison to the control strain. Our results document the function of flavin reductase that reduces flavins during indirubin biosynthesis and provide an important foundation for using the flavin reductases to improve indirubin production by engineered microorganisms.
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Affiliation(s)
- Jikun Du
- Central Research Laboratory, Shenzhen Hospital of Integrated Traditional Chinese and Western Medicine, Shenzhen, China
| | - Yuanhua Li
- Dongguan Key Laboratory of Traditional Chinese Medicine and New Pharmaceutical Development, School of Pharmacy, Guangdong Medical University, Dongguan, China
| | - Zhengzhuang Chen
- Central Research Laboratory, Shenzhen Hospital of Integrated Traditional Chinese and Western Medicine, Shenzhen, China
- Postgraduate Training Base of Guangzhou University of Chinese Medicine, Shenzhen Hospital of Integrated Traditional Chinese and Western Medicine, Shenzhen, China
| | - Chang Wang
- Central Research Laboratory, Shenzhen Hospital of Integrated Traditional Chinese and Western Medicine, Shenzhen, China
- Postgraduate Training Base of Guangzhou University of Chinese Medicine, Shenzhen Hospital of Integrated Traditional Chinese and Western Medicine, Shenzhen, China
| | - Yali Huang
- Basic Medical Science College, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Li Li
- Dongguan Key Laboratory of Traditional Chinese Medicine and New Pharmaceutical Development, School of Pharmacy, Guangdong Medical University, Dongguan, China
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2
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Shen Y, Liu N, Wang Z. Recent advances in the culture-independent discovery of natural products using metagenomic approaches. Chin J Nat Med 2024; 22:100-111. [PMID: 38342563 DOI: 10.1016/s1875-5364(24)60585-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Indexed: 02/13/2024]
Abstract
Natural products derived from bacterial sources have long been pivotal in the discovery of drug leads. However, the cultivation of only about 1% of bacteria in laboratory settings has left a significant portion of biosynthetic diversity hidden within the genomes of uncultured bacteria. Advances in sequencing technologies now enable the exploration of genetic material from these metagenomes through culture-independent methods. This approach involves extracting genetic sequences from environmental DNA and applying a hybrid methodology that combines functional screening, sequence tag-based homology screening, and bioinformatic-assisted chemical synthesis. Through this process, numerous valuable natural products have been identified and synthesized from previously uncharted metagenomic territories. This paper provides an overview of the recent advancements in the utilization of culture-independent techniques for the discovery of novel biosynthetic gene clusters and bioactive small molecules within metagenomic libraries.
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Affiliation(s)
- Yiping Shen
- Laboratory of Microbial Drug Discovery, China Pharmaceutical University, Nanjing 211198, China
| | - Nan Liu
- Laboratory of Microbial Drug Discovery, China Pharmaceutical University, Nanjing 211198, China
| | - Zongqiang Wang
- Laboratory of Microbial Drug Discovery, China Pharmaceutical University, Nanjing 211198, China.
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3
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Du J, Li Y, Huang Y, Zhang D, Li L. Characterization of a novel monooxygenase originating from a deep-sea sediment metagenomic library. Appl Microbiol Biotechnol 2023; 107:6237-6249. [PMID: 37581624 DOI: 10.1007/s00253-023-12719-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 07/12/2023] [Accepted: 08/01/2023] [Indexed: 08/16/2023]
Abstract
Oxygenases are important biocatalysts to produce many industrially important biomolecules. Here, a novel oxygenase, named MoxA, was identified through screening of a deep-sea sediment metagenomic library. Sequence analysis showed MoxA contains 424 amino acid residues with a predicated molecular mass of 46.9 kDa. Multiple sequence alignment and phylogenetic analysis indicated the sequence might be a new member of monooxygenase subfamily. A recombinant MoxA was obtained through the functional expression of moxA gene in Escherichia coli. Characterization of the purified MoxA indicated that it is an alkaline oxygenase showing maximal activity at pH 8.0. The optimal temperature of MoxA was 37 ℃, and it retained more than 70% of its initial activity after 1 h at 20-50 ℃ exhibiting good thermostability. Furthermore, effect of metal ions and organic solvents on enzymatic activity was investigated, and the results showed that the activity of MoxA was enhanced by Cu2+, Zn2+, Co2+ and Mg2+ at 1 mM, and by Co2+, Ca2+ and Mg2+ at 5 mM. Moreover, the recombinant strain harboring MoxA was used as a whole-cell biocatalyst for the efficient biosynthesis of indigo showing promising conversion efficiency. The biochemical properties of MoxA indicated that it would provide great contribution for the indigo bioproduction. KEY POINTS: • A novel monooxygenase from a metagenomic library was characterized. • The activity of MoxA was enhanced by metal ions at 1 mM and 5 mM. • MoxA has an optimal temperature of 37 ℃ and exhibited high conversion capacity.
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Affiliation(s)
- Jikun Du
- Central Research Laboratory, Shenzhen Hospital of Integrated Traditional Chinese and Western Medicine, Shenzhen, 518104, China.
| | - Yuanhua Li
- Central Research Laboratory, Shenzhen Hospital of Integrated Traditional Chinese and Western Medicine, Shenzhen, 518104, China
- Traditional Chinese Medicine and New Drug Research Institute, Department of Pharmacology, Guangdong Medical University, Dongguan, 523808, China
| | - Yali Huang
- College of Fundamental Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Dawei Zhang
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou, 510006, China
| | - Li Li
- Traditional Chinese Medicine and New Drug Research Institute, Department of Pharmacology, Guangdong Medical University, Dongguan, 523808, China.
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4
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Pabbathi NPP, Velidandi A, Tavarna T, Gupta S, Raj RS, Gandam PK, Baadhe RR. Role of metagenomics in prospecting novel endoglucanases, accentuating functional metagenomics approach in second-generation biofuel production: a review. BIOMASS CONVERSION AND BIOREFINERY 2023; 13:1371-1398. [PMID: 33437563 PMCID: PMC7790359 DOI: 10.1007/s13399-020-01186-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/30/2020] [Accepted: 12/01/2020] [Indexed: 05/02/2023]
Abstract
As the fossil fuel reserves are depleting rapidly, there is a need for alternate fuels to meet the day to day mounting energy demands. As fossil fuel started depleting, a quest for alternate forms of fuel was initiated and biofuel is one of its promising outcomes. First-generation biofuels are made from edible sources like vegetable oils, starch, and sugars. Second-generation biofuels (SGB) are derived from lignocellulosic crops and the third-generation involves algae for biofuel production. Technical challenges in the production of SGB are hampering its commercialization. Advanced molecular technologies like metagenomics can help in the discovery of novel lignocellulosic biomass-degrading enzymes for commercialization and industrial production of SGB. This review discusses the metagenomic outcomes to enlighten the importance of unexplored habitats for novel cellulolytic gene mining. It also emphasizes the potential of different metagenomic approaches to explore the uncultivable cellulose-degrading microbiome as well as cellulolytic enzymes associated with them. This review also includes effective pre-treatment technology and consolidated bioprocessing for efficient biofuel production.
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Affiliation(s)
- Ninian Prem Prashanth Pabbathi
- Integrated Biorefinery Research Lab, Department of Biotechnology, National Institute of Technology, Warangal, Telangana 506004 India
| | - Aditya Velidandi
- Integrated Biorefinery Research Lab, Department of Biotechnology, National Institute of Technology, Warangal, Telangana 506004 India
| | - Tanvi Tavarna
- Integrated Biorefinery Research Lab, Department of Biotechnology, National Institute of Technology, Warangal, Telangana 506004 India
| | - Shreyash Gupta
- Integrated Biorefinery Research Lab, Department of Biotechnology, National Institute of Technology, Warangal, Telangana 506004 India
| | - Ram Sarvesh Raj
- Integrated Biorefinery Research Lab, Department of Biotechnology, National Institute of Technology, Warangal, Telangana 506004 India
| | - Pradeep Kumar Gandam
- Integrated Biorefinery Research Lab, Department of Biotechnology, National Institute of Technology, Warangal, Telangana 506004 India
| | - Rama Raju Baadhe
- Integrated Biorefinery Research Lab, Department of Biotechnology, National Institute of Technology, Warangal, Telangana 506004 India
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5
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Linke JA, Rayat A, Ward JM. Production of indigo by recombinant bacteria. BIORESOUR BIOPROCESS 2023; 10:20. [PMID: 36936720 PMCID: PMC10011309 DOI: 10.1186/s40643-023-00626-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 01/06/2023] [Indexed: 03/15/2023] Open
Abstract
Indigo is an economically important dye, especially for the textile industry and the dyeing of denim fabrics for jeans and garments. Around 80,000 tonnes of indigo are chemically produced each year with the use of non-renewable petrochemicals and the use and generation of toxic compounds. As many microorganisms and their enzymes are able to synthesise indigo after the expression of specific oxygenases and hydroxylases, microbial fermentation could offer a more sustainable and environmentally friendly manufacturing platform. Although multiple small-scale studies have been performed, several existing research gaps still hinder the effective translation of these biochemical approaches. No article has evaluated the feasibility and relevance of the current understanding and development of indigo biocatalysis for real-life industrial applications. There is no record of either established or practically tested large-scale bioprocess for the biosynthesis of indigo. To address this, upstream and downstream processing considerations were carried out for indigo biosynthesis. 5 classes of potential biocatalysts were identified, and 2 possible bioprocess flowsheets were designed that facilitate generating either a pre-reduced dye solution or a dry powder product. Furthermore, considering the publicly available data on the development of relevant technology and common bioprocess facilities, possible platform and process values were estimated, including titre, DSP yield, potential plant capacities, fermenter size and batch schedule. This allowed us to project the realistic annual output of a potential indigo biosynthesis platform as 540 tonnes. This was interpreted as an industrially relevant quantity, sufficient to provide an annual dye supply to a single industrial-size denim dyeing plant. The conducted sensitivity analysis showed that this anticipated output is most sensitive to changes in the reaction titer, which can bring a 27.8% increase or a 94.4% drop. Thus, although such a biological platform would require careful consideration, fine-tuning and optimization before real-life implementation, the recombinant indigo biosynthesis was found as already attractive for business exploitation for both, luxury segment customers and mass-producers of denim garments. Graphical Abstract Supplementary Information The online version contains supplementary material available at 10.1186/s40643-023-00626-7.
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Affiliation(s)
- Julia A. Linke
- grid.83440.3b0000000121901201Chemical Engineering Department, University College London (UCL), Torrington Place, London, WC1E 7JE UK
- grid.83440.3b0000000121901201Division of Medicine, University College London (UCL), 5 University Street, London, WC1E 6JF UK
| | - Andrea Rayat
- grid.83440.3b0000000121901201Biochemical Engineering Department, University College London (UCL), Gower St., London, WC1E 6BT UK
| | - John M. Ward
- grid.83440.3b0000000121901201Biochemical Engineering Department, University College London (UCL), Gower St., London, WC1E 6BT UK
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6
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Weiland-Bräuer N, Saleh L, Schmitz RA. Functional Metagenomics as a Tool to Tap into Natural Diversity of Valuable Biotechnological Compounds. Methods Mol Biol 2023; 2555:23-49. [PMID: 36306077 DOI: 10.1007/978-1-0716-2795-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The marine ecosystem covers more than 70% of the world's surface, and oceans represent a source of varied types of organisms due to the diversified environment. Consequently, the marine environment is an exceptional depot of novel bioactive natural products, with structural and chemical features generally not found in terrestrial habitats. Here, in particular, microbes represent a vast source of unknown and probably new physiological characteristics. They have evolved during extended evolutionary processes of physiological adaptations under various environmental conditions and selection pressures. However, to date, the biodiversity of marine microbes and the versatility of their bioactive compounds and metabolites have not been fully explored. Thus, metagenomic tools are required to exploit the untapped marine microbial diversity and their bioactive compounds. This chapter focuses on function-based marine metagenomics to screen for bioactive molecules of value for biotechnology. Functional metagenomic strategies are described, including sampling in the marine environment, constructing marine metagenomic large-insert libraries, and examples on function-based screens for quorum quenching and anti-biofilm activities.
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Affiliation(s)
- Nancy Weiland-Bräuer
- Institute for General Microbiology, Christian Albrechts University Kiel, Kiel, Germany
| | - Livía Saleh
- Institute for General Microbiology, Christian Albrechts University Kiel, Kiel, Germany
| | - Ruth A Schmitz
- Institute for General Microbiology, Christian Albrechts University Kiel, Kiel, Germany.
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7
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Carotenoid Cocktail Produced by An Antarctic Soil Flavobacterium with Biotechnological Potential. Microorganisms 2021; 9:microorganisms9122419. [PMID: 34946021 PMCID: PMC8704924 DOI: 10.3390/microorganisms9122419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/29/2021] [Accepted: 09/30/2021] [Indexed: 11/17/2022] Open
Abstract
Carotenoids are highly important in pigmentation, and its content in farmed crustaceans and fish correlates to their market value. These pigments also have a nutritional role in aquaculture where they are routinely added as a marine animal food supplement to ensure fish development and health. However, there is little information about carotenoids obtained from Antarctic bacteria and its use for pigmentation improvement and flesh quality in aquaculture. This study identified carotenoids produced by Antarctic soil bacteria. The pigmented strain (CN7) was isolated on modified Luria–Bertani (LB) media and incubated at 4 °C. This Gram-negative bacillus was identified by 16S rRNA analysis as Flavobacterium segetis. Pigment extract characterization was performed through high-performance liquid chromatography (HPLC) and identification with liquid chromatography–mass spectrometry (LC–MS). HPLC analyses revealed that this bacterium produces several pigments in the carotenoid absorption range (six peaks). LC–MS confirms the presence of one main peak corresponding to lutein or zeaxanthin (an isomer of lutein) and several other carotenoid pigments and intermediaries in a lower quantity. Therefore, we propose CN7 strain as an alternative model to produce beneficial carotenoid pigments with potential nutritional applications in aquaculture.
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8
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Strategies for Natural Products Discovery from Uncultured Microorganisms. Molecules 2021; 26:molecules26102977. [PMID: 34067778 PMCID: PMC8156983 DOI: 10.3390/molecules26102977] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 05/13/2021] [Accepted: 05/13/2021] [Indexed: 12/12/2022] Open
Abstract
Microorganisms are highly regarded as a prominent source of natural products that have significant importance in many fields such as medicine, farming, environmental safety, and material production. Due to this, only tiny amounts of microorganisms can be cultivated under standard laboratory conditions, and the bulk of microorganisms in the ecosystems are still unidentified, which restricts our knowledge of uncultured microbial metabolism. However, they could hypothetically provide a large collection of innovative natural products. Culture-independent metagenomics study has the ability to address core questions in the potential of NP production by cloning and analysis of microbial DNA derived directly from environmental samples. Latest advancements in next generation sequencing and genetic engineering tools for genome assembly have broadened the scope of metagenomics to offer perspectives into the life of uncultured microorganisms. In this review, we cover the methods of metagenomic library construction, and heterologous expression for the exploration and development of the environmental metabolome and focus on the function-based metagenomics, sequencing-based metagenomics, and single-cell metagenomics of uncultured microorganisms.
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9
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Fabara AN, Fraaije MW. Production of indigo through the use of a dual-function substrate and a bifunctional fusion enzyme. Enzyme Microb Technol 2020; 142:109692. [PMID: 33220871 DOI: 10.1016/j.enzmictec.2020.109692] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/06/2020] [Accepted: 10/12/2020] [Indexed: 10/23/2022]
Abstract
The current chemical process for industrial indigo production puts a heavy burden on the environment. An attractive option would be to develop an alternative biotechnological process which does not rely on a petrochemical. This study describes a new biotransformation approach in which l-tryptophan is used as starting material. Its conversion to indigo can be achieved through recombinant overexpression of a bifunctional fusion enzyme, flavin-containing monooxygenase (FMO) fused to tryptophanase (TRP). First, TRP converts l-tryptophan into pyruvate, ammonia and indole. The formed indole serves as substrate for FMO, resulting in indigo formation, while pyruvate fuels the cells for regenerating the required NADPH. To optimize this bioconversion, different fusion constructs were tested. Fusing TRP to FMO at either the N-terminus (TRP-FMO) or the C-terminus (FMO-TRP) resulted in similar high expression levels of bifunctional fusion enzymes. Using whole cells and l-tryptophan as a precursor, high production levels of indigo could be obtained, significantly higher when compared with cells containing only overexpressed FMO. The TRP-FMO containing cells gave the highest yield of indigo resulting in full conversion of 2.0 g l-tryptophan into 1.7 g indigo per liter of culture. The process developed in this study provides an alternative biotransformation approach for the production of indigo starting from biobased starting material.
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Affiliation(s)
- Andrea N Fabara
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG, Groningen, The Netherlands
| | - Marco W Fraaije
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG, Groningen, The Netherlands.
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10
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Boutin S, Dalpke AH. The Microbiome: A Reservoir to Discover New Antimicrobials Agents. Curr Top Med Chem 2020; 20:1291-1299. [DOI: 10.2174/1568026620666200320112731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 02/10/2020] [Accepted: 02/17/2020] [Indexed: 02/01/2023]
Abstract
Nature offered mankind the first golden era of discovery of novel antimicrobials based on
the ability of eukaryotes or micro-organisms to produce such compounds. The microbial world proved
to be a huge reservoir of such antimicrobial compounds which play important functional roles in every
environment. However, most of those organisms are still uncultivable in a classical way, and therefore,
the use of extended culture or DNA based methods (metagenomics) to discover novel compounds
promises usefulness. In the past decades, the advances in next-generation sequencing and bioinformatics
revealed the enormous diversity of the microbial worlds and the functional repertoire available for
studies. Thus, data-mining becomes of particular interest in the context of the increased need for new
antibiotics due to antimicrobial resistance and the rush in antimicrobial discovery. In this review, an
overview of principles will be presented to discover new natural compounds from the microbiome. We
describe culture-based and culture-independent (metagenomic) approaches that have been developed to
identify new antimicrobials and the input of those methods in the field as well as their limitations.
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Affiliation(s)
- Sébastien Boutin
- Department of Infectious Diseases, Medical Microbiology and Hygiene, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Alexander H. Dalpke
- Institute of Medical Microbiology and Hygiene, Medical Faculty, Technische Universität Dresden, 01307 Dresden, Germany
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11
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Fabara AN, Fraaije MW. An overview of microbial indigo-forming enzymes. Appl Microbiol Biotechnol 2019; 104:925-933. [PMID: 31834440 PMCID: PMC6962290 DOI: 10.1007/s00253-019-10292-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/23/2019] [Accepted: 11/28/2019] [Indexed: 11/03/2022]
Abstract
Indigo is one of the oldest textile dyes and was originally prepared from plant material. Nowadays, indigo is chemically synthesized at a large scale to satisfy the demand for dyeing jeans. The current indigo production processes are based on fossil feedstocks; therefore, it is highly attractive to develop a more sustainable and environmentally friendly biotechnological process for the production of this popular dye. In the past decades, a number of natural and engineered enzymes have been identified that can be used for the synthesis of indigo. This mini-review provides an overview of the various microbial enzymes which are able to produce indigo and discusses the advantages and disadvantages of each biocatalytic system.
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Affiliation(s)
- Andrea N Fabara
- Molecular Enzymology group, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Marco W Fraaije
- Molecular Enzymology group, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
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Ngangbam AK, Mouatt P, Smith J, Waters DLE, Benkendorff K. Bromoperoxidase Producing Bacillus spp. Isolated from the Hypobranchial Glands of a Muricid Mollusc Are Capable of Tyrian Purple Precursor Biogenesis. Mar Drugs 2019; 17:md17050264. [PMID: 31058830 PMCID: PMC6562550 DOI: 10.3390/md17050264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 04/26/2019] [Accepted: 04/30/2019] [Indexed: 11/16/2022] Open
Abstract
The secondary metabolite Tyrian purple, also known as shellfish purple and royal purple, is a dye with historical importance for humans. The biosynthetic origin of Tyrian purple in Muricidae molluscs is not currently known. A possible role for symbiotic bacteria in the production of tyrindoxyl sulphate, the precursor to Tyrian purple stored in the Australian species, Dicathais orbita, has been proposed. This study aimed to culture bacterial symbionts from the purple producing hypobranchial gland, and screen the isolates for bromoperoxidase genes using molecular methods. The ability of bromoperoxidase positive isolates to produce the brominated indole precursor to Tyrian purple was then established by extraction of the culture, and analysis by liquid chromatography-mass spectrometry (LC-MS). In total, 32 bacterial isolates were cultured from D. orbita hypobranchial glands, using marine agar, marine agar with hypobranchial gland aqueous extracts, blood agar, thiosulphate citrate bile salts sucrose agar, and cetrimide agar at pH 7.2. These included 26 Vibrio spp., two Bacillus spp., one Phaeobacter sp., one Shewanella sp., one Halobacillus sp. and one Pseudoalteromonas sp. The two Bacillus species were the only isolates found to have coding sequences for bromoperoxidase enzymes. LC-MS analysis of the supernatant and cell pellets from the bromoperoxidase producing Bacillus spp. cultured in tryptone broth, supplemented with KBr, confirmed their ability to produce the brominated precursor to Tyrian purple, tyrindoxyl sulphate. This study supports a potential role for symbiotic Bacillus spp. in the biosynthesis of Tyrian purple.
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Affiliation(s)
- Ajit Kumar Ngangbam
- Marine Ecology Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW 2480, Australia.
| | - Peter Mouatt
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW 2480, Australia.
| | - Joshua Smith
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW 2480, Australia.
| | - Daniel L E Waters
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW 2480, Australia.
- ARC Industrial Transformation Training Centre for Functional Grains, Charles Sturt University, Wagga, NSW 2650, Australia.
| | - Kirsten Benkendorff
- Marine Ecology Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW 2480, Australia.
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Abstract
Natural products have long played a pivotal role in the development of therapeutics for a variety of diseases. Traditionally, soil and marine environments have provided a rich reservoir from which diverse chemical scaffolds could be discovered. Recently, the human microbiome has been recognized as a promising niche from which secondary metabolites with therapeutic potential have begun to be isolated. In this Review, we address how the expansive history of identifying bacterial natural products in other environments is informing the approaches being brought to bear on the study of the human microbiota. We also touch on how these tools can lead to insights about microbe-microbe and host-microbe interactions and help generate biological hypotheses that may lead to developments of new therapeutic modalities.
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14
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Brahami A, Castonguay A, Déziel É. Novel 'Bacteriospray' Method Facilitates the Functional Screening of Metagenomic Libraries for Antimicrobial Activity. Methods Protoc 2019; 2:mps2010004. [PMID: 31164589 PMCID: PMC6481063 DOI: 10.3390/mps2010004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 12/29/2018] [Accepted: 01/01/2019] [Indexed: 01/14/2023] Open
Abstract
Metagenomic techniques, notably the cloning of environmental DNA (eDNA) into surrogate hosts, have given access to the genome of uncultured bacteria. However, the determination of gene functions based on DNA sequences alone remains a significant challenge. The functional screening of metagenomic libraries represents an interesting approach in the discovery of microbial metabolites. We describe here an optimized screening approach that facilitates the identification of new antimicrobials among large metagenomic libraries. Notably, we report a detailed genomic library construction protocol using Escherichia coli DH10B as a surrogate host, and demonstrate how vector/genomic DNA dephosphorylation, ligase inactivation, dialysis of the ligation product and vector/genomic DNA ratio greatly influence clone recovery. Furthermore, we describe the use of an airbrush device to screen E. coli metagenomic libraries for their antibacterial activity against Staphylococcus aureus, a method we called bacteriospray. This bacterial spraying tool greatly facilitates and improves the functional screening of large genomic libraries, as it conveniently allows the production of a thinner and more uniform layer of target bacteria compared to the commonly used overlay method, resulting in the screening of 5–10 times more clones per agar plate. Using the Burkholderia thailandensis E264 genomic DNA as a proof of concept, four clones out of 70,000 inhibited the growth of S. aureus and were found to each contain a DNA insert. Analysis of these chromosomic fragments revealed genomic regions never previously reported to be responsible for the production of antimicrobials, nor predicted by bioinformatics tools.
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Affiliation(s)
- Anissa Brahami
- INRS-Institut Armand-Frappier, Laval, QC H7V 1B7, Canada.
| | | | - Éric Déziel
- INRS-Institut Armand-Frappier, Laval, QC H7V 1B7, Canada.
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15
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Methods in Metagenomics and Environmental Biotechnology. NANOSCIENCE AND BIOTECHNOLOGY FOR ENVIRONMENTAL APPLICATIONS 2019. [DOI: 10.1007/978-3-319-97922-9_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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16
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Ma Q, Zhang X, Qu Y. Biodegradation and Biotransformation of Indole: Advances and Perspectives. Front Microbiol 2018; 9:2625. [PMID: 30443243 PMCID: PMC6221969 DOI: 10.3389/fmicb.2018.02625] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 10/15/2018] [Indexed: 11/17/2022] Open
Abstract
Indole is long regarded as a typical N-heterocyclic aromatic pollutant in industrial and agricultural wastewater, and recently it has been identified as a versatile signaling molecule with wide environmental distributions. An exponentially growing number of researches have been reported on indole due to its significant roles in bacterial physiology, pathogenesis, animal behavior and human diseases. From the viewpoint of both environmental bioremediation and biological studies, the researches on metabolism and fates of indole are important to realize environmental treatment and illuminate its biological function. Indole can be produced from tryptophan by tryptophanase in many bacterial species. Meanwhile, various bacterial strains have obtained the ability to transform and degrade indole. The characteristics and pathways for indole degradation have been investigated for a century, and the functional genes for indole aerobic degradation have also been uncovered recently. Interestingly, many oxygenases have proven to be able to oxidize indole to indigo, and this historic and motivating case for biological applications has attracted intensive attention for decades. Herein, the bacteria, enzymes and pathways for indole production, biodegradation and biotransformation are systematically summarized, and the future researches on indole-microbe interactions are also prospected.
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Affiliation(s)
- Qiao Ma
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian, China
| | - Xuwang Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Food and Environment, Dalian University of Technology, Panjin, China
| | - Yuanyuan Qu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, China
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17
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Hug JJ, Bader CD, Remškar M, Cirnski K, Müller R. Concepts and Methods to Access Novel Antibiotics from Actinomycetes. Antibiotics (Basel) 2018; 7:E44. [PMID: 29789481 PMCID: PMC6022970 DOI: 10.3390/antibiotics7020044] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 05/14/2018] [Accepted: 05/17/2018] [Indexed: 12/25/2022] Open
Abstract
Actinomycetes have been proven to be an excellent source of secondary metabolites for more than half a century. Exhibiting various bioactivities, they provide valuable approved drugs in clinical use. Most microorganisms are still untapped in terms of their capacity to produce secondary metabolites, since only a small fraction can be cultured in the laboratory. Thus, improving cultivation techniques to extend the range of secondary metabolite producers accessible under laboratory conditions is an important first step in prospecting underexplored sources for the isolation of novel antibiotics. Currently uncultured actinobacteria can be made available by bioprospecting extreme or simply habitats other than soil. Furthermore, bioinformatic analysis of genomes reveals most producers to harbour many more biosynthetic gene clusters than compounds identified from any single strain, which translates into a silent biosynthetic potential of the microbial world for the production of yet unknown natural products. This review covers discovery strategies and innovative methods recently employed to access the untapped reservoir of natural products. The focus is the order of actinomycetes although most approaches are similarly applicable to other microbes. Advanced cultivation methods, genomics- and metagenomics-based approaches, as well as modern metabolomics-inspired methods are highlighted to emphasise the interplay of different disciplines to improve access to novel natural products.
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Affiliation(s)
- Joachim J Hug
- Department Microbial Natural Products, Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI) and Department of Pharmacy, Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, 38124 Braunschweig, Germany.
| | - Chantal D Bader
- Department Microbial Natural Products, Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI) and Department of Pharmacy, Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, 38124 Braunschweig, Germany.
| | - Maja Remškar
- Department Microbial Natural Products, Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI) and Department of Pharmacy, Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, 38124 Braunschweig, Germany.
| | - Katarina Cirnski
- Department Microbial Natural Products, Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI) and Department of Pharmacy, Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, 38124 Braunschweig, Germany.
| | - Rolf Müller
- Department Microbial Natural Products, Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI) and Department of Pharmacy, Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, 38124 Braunschweig, Germany.
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18
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Rajalaxmi M, Beema Shafreen R, Chithiraiselvi K, Karutha Pandian S. An in vitro and in silico identification of antibiofilm small molecules from seawater metaclone SWMC166 against Vibrio cholerae O1. Mol Cell Probes 2018; 39:14-24. [PMID: 29574083 DOI: 10.1016/j.mcp.2018.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/06/2018] [Accepted: 03/20/2018] [Indexed: 01/27/2023]
Abstract
This study aimed to determine the antibiofilm activity of seawater microbes against Vibrio cholerae (VCO1) through functional metagenomics approach. A metagenomic library was constructed from Palk Bay seawater and the library was screened to identify the biofilm inhibitory metaclone. Metaclone SWMC166 (harbouring ∼30 kb metagenomic insert) was found to exhibit antibiofilm activity against VCO1. The biofilm inhibitory potential of partially purified ethyl acetate extract of SWMC166 (EA166) was further evaluated through microscopic studies and biochemical assays. Further, EA166 treated VCO1 divulged up-regulation of genes involved in high cell density-mediated quorum sensing (QS) pathway which was analysed by real-time PCR. In order to identify the genes of interest (within ∼30 kb insert), subcloning was performed through shotgun approach. Small molecules from positive subclones SC5 and SC8 were identified through HRLC-MS analysis. Resulted small molecules were docked against QS receptors of V. cholerae to identify the bioactive metabolites. Docking studies revealed that totally seven metabolites were able to interact with QS receptors that can possibly trigger the QS cascade and sequentially inhibit the biofilm formation and virulence factors of VCO1.
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Affiliation(s)
- Murugan Rajalaxmi
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, 630 003, India
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20
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Lee MH, Khan R, Tao W, Choi K, Lee SY, Lee JW, Hwang EC, Lee SW. Soil metagenome-derived 3-hydroxypalmitic acid methyl ester hydrolases suppress extracellular polysaccharide production in Ralstonia solanacearum. J Biotechnol 2018; 270:30-38. [PMID: 29407418 DOI: 10.1016/j.jbiotec.2018.01.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/30/2018] [Accepted: 01/31/2018] [Indexed: 10/18/2022]
Abstract
Autoinducers are indispensable for bacterial cell-cell communication. However, due to the reliance on culture-based techniques, few autoinducer-hydrolyzing enzymes are known. In this study, we characterized soil metagenome-derived unique enzymes capable of hydrolyzing 3-hydroxypalmitic acid methyl ester (3-OH PAME), an autoinducer of the plant pathogenic bacterium Ralstonia solanacearum. Among 146 candidate lipolytic clones from a soil metagenome library, 4 unique enzymes capable of hydrolyzing the autoinducer 3-OH PAME, termed ELP86, ELP96, ELP104, and EstDL33, were selected and characterized. Phylogenetic analysis revealed that metagenomic enzymes were novel esterase/lipase candidates as they clustered as novel subfamilies of family I, V, X, and family XI. The purified enzymes displayed various levels of hydrolytic activities towards 3-OH PAME with optimum activity at 40-50 °C and pH 7-10. Interestingly, ELP104 also displayed N-(3-oxohexanoyl)-L-homoserine lactone hydrolysis activity. Heterologous expression of the gene encoding 3-OH PAME hydrolase in R. solanacearum significantly decreased exopolysaccharide production without affecting bacterial growth. mRNA transcription analysis revealed that genes regulated by quorum-sensing, such as phcA and xpsR, were significantly down-regulated in the stationary growth phase of R. solanacearum. Therefore, metagenomic enzymes are capable of quorum-quenching by hydrolyzing the autoinducer 3-OH PAME, which could be used as a biocontrol strategy against bacterial wilt.
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Affiliation(s)
- Myung Hwan Lee
- Department of Applied Bioscience, Dong-A University, Busan 49315, Republic of Korea
| | - Raees Khan
- Department of Applied Bioscience, Dong-A University, Busan 49315, Republic of Korea
| | - Weixin Tao
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Wuhan University, Wuhan, 430072, China
| | - Kihyuck Choi
- Department of Applied Bioscience, Dong-A University, Busan 49315, Republic of Korea
| | - Seung Yeup Lee
- Department of Applied Bioscience, Dong-A University, Busan 49315, Republic of Korea
| | - Jae Wook Lee
- Department of Chemistry, Dong-A University, Busan 49315, Republic of Korea
| | - Eul Chul Hwang
- Department of Applied Bioscience, Dong-A University, Busan 49315, Republic of Korea
| | - Seon-Woo Lee
- Department of Applied Bioscience, Dong-A University, Busan 49315, Republic of Korea.
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21
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Boddu RS, Divakar K. Metagenomic Insights into Environmental Microbiome and Their Application in Food/Pharmaceutical Industry. Microb Biotechnol 2018. [DOI: 10.1007/978-981-10-7140-9_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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22
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Kugel S, Baunach M, Baer P, Ishida-Ito M, Sundaram S, Xu Z, Groll M, Hertweck C. Cryptic indole hydroxylation by a non-canonical terpenoid cyclase parallels bacterial xenobiotic detoxification. Nat Commun 2017. [PMID: 28643772 PMCID: PMC5481743 DOI: 10.1038/ncomms15804] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Terpenoid natural products comprise a wide range of molecular architectures that typically result from C–C bond formations catalysed by classical type I/II terpene cyclases. However, the molecular diversity of biologically active terpenoids is substantially increased by fully unrelated, non-canonical terpenoid cyclases. Their evolutionary origin has remained enigmatic. Here we report the in vitro reconstitution of an unusual flavin-dependent bacterial indoloterpenoid cyclase, XiaF, together with a designated flavoenzyme-reductase (XiaP) that mediates a key step in xiamycin biosynthesis. The crystal structure of XiaF with bound FADH2 (at 2.4 Å resolution) and phylogenetic analyses reveal that XiaF is, surprisingly, most closely related to xenobiotic-degrading enzymes. Biotransformation assays show that XiaF is a designated indole hydroxylase that can be used for the production of indigo and indirubin. We unveil a cryptic hydroxylation step that sets the basis for terpenoid cyclization and suggest that the cyclase has evolved from xenobiotics detoxification enzymes. The biosynthesis of xiamycin, an antimicrobial bacterial indolosesquiterpenoid, involves an unusual cyclization cascade. Here, the authors characterise the XiaF enzyme, which resembles xenobiont-degrading enzymes and is responsible for a hidden indole hydroxylation step that triggers the cyclization reaction.
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Affiliation(s)
- Susann Kugel
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
| | - Martin Baunach
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
| | - Philipp Baer
- Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Mie Ishida-Ito
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
| | - Srividhya Sundaram
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
| | - Zhongli Xu
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany
| | - Michael Groll
- Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Beutenbergstr. 11a, 07745 Jena, Germany.,Natural Product Chemistry, Friedrich Schiller University, 07743 Jena, Germany
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23
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Extraction and Quantification of Bioactive Tyrian Purple Precursors: A Comparative and Validation Study from the Hypobranchial Gland of a Muricid Dicathais orbita. Molecules 2016; 21:molecules21121672. [PMID: 27929402 PMCID: PMC6273837 DOI: 10.3390/molecules21121672] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/21/2016] [Accepted: 11/28/2016] [Indexed: 12/27/2022] Open
Abstract
Muricidae are marine molluscs known for the production of Tyrian purple and bioactive precursor compounds. A validation study for the extraction and analysis of secondary metabolites found in the hypobranchial gland of the muricid Dicathais orbita is reported, using high performance liquid chromatography–mass spectrometry (HPLC-MS) with diode array detector (DAD). Quantification of the dominant secondary metabolites from D. orbita is described, followed by a comparison of solvent extraction procedures and stability studies. The intra- and inter-day relative standard deviation (RSD) for tyrindoxyl sulphate was 0.46% and 0.17%, respectively. The quantification was linear for standards murexine, 6-bromoisatin, and tyrindoxyl sulphate. The limits of detection were 0.03, 0.004, and 0.07 mg/mL, respectively, and the limits of quantification were 0.09, 0.01, and 0.22 mg/mL, respectively. The results showed that alcoholic solvents were better for extracting choline ester and indoxyl sulphate ultimate precursors, while chloroform was more suitable for the extraction of the intermediate precursors. Multivariate analysis revealed significant differences in extract composition according to the solvent used. Stability testing showed an increase of the oxidative compounds 6-bromoisatin and putative tyrindoxyl S-oxide sulphate in the ethanol extracts while more degradation products were seen in the chloroform extracts after months of cold storage. The validated method was found to be simple, reproducible, precise, and suitable for quantification of the secondary metabolites of muricid molluscs for dye precursor and nutraceutical quality control, as well as applications in marine chemical ecology.
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24
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Adu-Oppong B, Gasparrini AJ, Dantas G. Genomic and functional techniques to mine the microbiome for novel antimicrobials and antimicrobial resistance genes. Ann N Y Acad Sci 2016; 1388:42-58. [PMID: 27768825 DOI: 10.1111/nyas.13257] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 08/16/2016] [Accepted: 08/22/2016] [Indexed: 02/07/2023]
Abstract
Microbial communities contain diverse bacteria that play important roles in every environment. Advances in sequencing and computational methodologies over the past decades have illuminated the phylogenetic and functional diversity of microbial communities from diverse habitats. Among the activities encoded in microbiomes are the abilities to synthesize and resist small molecules, yielding antimicrobial activity. These functions are of particular interest when viewed in light of the public health emergency posed by the increase in clinical antimicrobial resistance and the dwindling antimicrobial discovery and approval pipeline, and given the intimate ecological and evolutionary relationship between antimicrobial biosynthesis and resistance. Here, we review genomic and functional methods that have been developed for accessing the antimicrobial biosynthesis and resistance capacity of microbiomes and highlight outstanding examples of their applications.
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Affiliation(s)
- Boahemaa Adu-Oppong
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, Missouri
| | - Andrew J Gasparrini
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, Missouri
| | - Gautam Dantas
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, Missouri.,Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, Missouri.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri.,Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri
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25
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Luby E, Ibekwe AM, Zilles J, Pruden A. Molecular Methods for Assessment of Antibiotic Resistance in Agricultural Ecosystems: Prospects and Challenges. JOURNAL OF ENVIRONMENTAL QUALITY 2016; 45:441-453. [PMID: 27065390 DOI: 10.2134/jeq2015.07.0367] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Agricultural ecosystems are of special interest for monitoring the potential for antibiotic resistance to spread through the environment and contribute to human exposure. Molecular methods, which target DNA, RNA, and other molecular components of bacterial cells, present certain advantages for characterizing and quantifying markers of antibiotic resistance and their horizontal gene transfer. These include rapid, unambiguous detection of targets; consistent results; and avoidance of culture bias. However, molecular methods are also subject to limitations that are not always clearly addressed or taken into consideration in the interpretation of scientific data. In particular, DNA-based methods do not directly assess viability or presence within an intact bacterial host, but such information may be inferred based on appropriate experimental design or in concert with complementary methods. The purpose of this review is to provide an overview of existing molecular methods for tracking antibiotic resistance in agricultural ecosystems, to define their strengths and weaknesses, and to recommend a path forward for future applications of molecular methods and standardized reporting in the literature. This will guide research along the farm-to-fork continuum and support comparability of the growing number of studies in the literature in a manner that informs management decisions and policy development.
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26
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O'Mahony MM, Henneberger R, Selvin J, Kennedy J, Doohan F, Marchesi JR, Dobson ADW. Inhibition of the growth of Bacillus subtilis DSM10 by a newly discovered antibacterial protein from the soil metagenome. Bioengineered 2016; 6:89-98. [PMID: 25692994 PMCID: PMC4601227 DOI: 10.1080/21655979.2015.1018493] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
A functional metagenomics based approach exploiting the microbiota of suppressive soils from an organic field site has succeeded in the identification of a clone with the ability to inhibit the growth of Bacillus subtilis DSM10. Sequencing of the fosmid identified a putative β-lactamase-like gene abgT. Transposon mutagenesis of the abgT gene resulted in a loss in ability to inhibit the growth of B. subtilis DSM10. Further analysis of the deduced amino acid sequence of AbgT revealed moderate homology to esterases, suggesting that the protein may possess hydrolytic activity. Weak lipolytic activity was detected; however the clone did not appear to produce any β-lactamase activity. Phylogenetic analysis revealed the protein is a member of the family VIII group of lipase/esterases and clusters with a number of proteins of metagenomic origin. The abgT gene was sub-cloned into a protein expression vector and when introduced into the abgT transposon mutant clones restored the ability of the clones to inhibit the growth of B. subtilis DSM10, clearly indicating that the abgT gene is involved in the antibacterial activity. While the precise role of this protein has yet to fully elucidated, it may be involved in the generation of free fatty acid with antibacterial properties. Thus functional metagenomic approaches continue to provide a significant resource for the discovery of novel functional proteins and it is clear that hydrolytic enzymes, such as AbgT, may be a potential source for the development of future antimicrobial therapies.
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Affiliation(s)
- Mark M O'Mahony
- a School of Microbiology and Marine Biotechnology Center; Environmental Research Institute; University College Cork ; Cork , Ireland
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27
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Metagenomics: Retrospect and Prospects in High Throughput Age. BIOTECHNOLOGY RESEARCH INTERNATIONAL 2015; 2015:121735. [PMID: 26664751 PMCID: PMC4664791 DOI: 10.1155/2015/121735] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 10/26/2015] [Indexed: 01/30/2023]
Abstract
In recent years, metagenomics has emerged as a powerful tool for mining of hidden microbial treasure in a culture independent manner. In the last two decades, metagenomics has been applied extensively to exploit concealed potential of microbial communities from almost all sorts of habitats. A brief historic progress made over the period is discussed in terms of origin of metagenomics to its current state and also the discovery of novel biological functions of commercial importance from metagenomes of diverse habitats. The present review also highlights the paradigm shift of metagenomics from basic study of community composition to insight into the microbial community dynamics for harnessing the full potential of uncultured microbes with more emphasis on the implication of breakthrough developments, namely, Next Generation Sequencing, advanced bioinformatics tools, and systems biology.
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28
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Ngangbam AK, Baten A, Waters DLE, Whalan S, Benkendorff K. Characterization of Bacterial Communities Associated with the Tyrian Purple Producing Gland in a Marine Gastropod. PLoS One 2015; 10:e0140725. [PMID: 26488885 PMCID: PMC4619447 DOI: 10.1371/journal.pone.0140725] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 09/28/2015] [Indexed: 11/19/2022] Open
Abstract
Dicathais orbita is a marine mollusc recognised for the production of anticancer compounds that are precursors to Tyrian purple. This study aimed to assess the diversity and identity of bacteria associated with the Tyrian purple producing hypobranchial gland, in comparison with foot tissue, using a high-throughput sequencing approach. Taxonomic and phylogenetic analysis of variable region V1-V3 of 16S rRNA bacterial gene amplicons in QIIME and MEGAN were carried out. This analysis revealed a highly diverse bacterial assemblage associated with the hypobranchial gland and foot tissues of D. orbita. The dominant bacterial phylum in the 16S rRNA bacterial profiling data set was Proteobacteria followed by Bacteroidetes, Tenericutes and Spirochaetes. In comparison to the foot, the hypobranchial gland had significantly lower bacterial diversity and a different community composition, based on taxonomic assignment at the genus level. A higher abundance of indole producing Vibrio spp. and the presence of bacteria with brominating capabilities in the hypobranchial gland suggest bacteria have a potential role in biosynthesis of Tyrian purple in D. orbita.
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Affiliation(s)
- Ajit Kumar Ngangbam
- Marine Ecology Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW 2480, Australia
| | - Abdul Baten
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW 2480, Australia
| | - Daniel L. E. Waters
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW 2480, Australia
| | - Steve Whalan
- Marine Ecology Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW 2480, Australia
| | - Kirsten Benkendorff
- Marine Ecology Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW 2480, Australia
- * E-mail:
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29
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Lin GH, Chen HP, Shu HY. Detoxification of Indole by an Indole-Induced Flavoprotein Oxygenase from Acinetobacter baumannii. PLoS One 2015; 10:e0138798. [PMID: 26390211 PMCID: PMC4577076 DOI: 10.1371/journal.pone.0138798] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 09/03/2015] [Indexed: 11/17/2022] Open
Abstract
Indole, a derivative of the amino acid tryptophan, is a toxic signaling molecule, which can inhibit bacterial growth. To overcome indole-induced toxicity, many bacteria have developed enzymatic defense systems to convert indole to non-toxic, water-insoluble indigo. We previously demonstrated that, like other aromatic compound-degrading bacteria, Acinetobacter baumannii can also convert indole to indigo. However, no work has been published investigating this mechanism. Here, we have shown that the growth of wild-type A. baumannii is severely inhibited in the presence of 3.5 mM indole. However, at lower concentrations, growth is stable, implying that the bacteria may be utilizing a survival mechanism to oxidize indole. To this end, we have identified a flavoprotein oxygenase encoded by the iifC gene of A. baumannii. Further, our results suggest that expressing this recombinant oxygenase protein in Escherichia coli can drive indole oxidation to indigo in vitro. Genome analysis shows that the iif operon is exclusively present in the genomes of A. baumannii and Pseudomonas syringae pv. actinidiae. Quantitative PCR and Western blot analysis also indicate that the iif operon is activated by indole through the AraC-like transcriptional regulator IifR. Taken together, these data suggest that this species of bacteria utilizes a novel indole-detoxification mechanism that is modulated by IifC, a protein that appears to be, at least to some extent, regulated by IifR.
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Affiliation(s)
- Guang-Huey Lin
- Microbial Genetics Laboratory, Department of Microbiology, Tzu-Chi University, Hualien, Taiwan
| | - Hao-Ping Chen
- Department of Biochemistry, School of Medicine, Tzu-Chi University, Hualien, Taiwan
| | - Hung-Yu Shu
- Department of Bioscience Technology, Chang Jung Christian University, Tainan, Taiwan
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30
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Arivaradarajan P, Warburton PJ, Paramasamy G, Nair SP, Allan E, Mullany P. Identification of an antibacterial protein by functional screening of a human oral metagenomic library. FEMS Microbiol Lett 2015; 362:fnv142. [PMID: 26347298 DOI: 10.1093/femsle/fnv142] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2015] [Indexed: 11/13/2022] Open
Abstract
Screening of a bacterial artificial chromosome (BAC) library containing metagenomic DNA from human plaque and saliva allowed the isolation of four clones producing antimicrobial activity. Three of these were pigmented and encoded homologues of glutamyl-tRNA reductase (GluTR), an enzyme involved in the C5 pathway leading to tetrapyrole synthesis, and one clone had antibacterial activity with no pigmentation. The latter contained a BAC with an insert of 15.6 kb. Initial attempts to localize the gene(s) responsible for antimicrobial activity by subcloning into pUC-based vectors failed. A new plasmid for toxic gene expression (pTGEX) was designed enabling localization of the antibacterial activity to a 4.7-kb HindIII fragment. Transposon mutagenesis localized the gene to an open reading frame of 483 bp designated antibacterial protein1 (abp1). Abp1 was 94% identical to a hypothetical protein of Neisseria subflava (accession number WP_004519448.1). An Escherichia coli clone expressing Abp1 exhibited antibacterial activity against Bacillus subtilis BS78H, Staphylococcus epidermidis NCTC 11964 and B4268, and S. aureus NCTC 12493,ATCC 35696 and NCTC 11561. However, no antibacterial activity was observed against Pseudomonas aeruginosa ATCC 9027, N. subflava ATCC A1078, E. coli K12 JM109 and BL21(DE3) Fusobacterium nucleatum ATCC 25586 and NCTC 11326, Prevotella intermedia ATCC 25611, Veillonella parvula ATCC 10790 or Lactobacillus casei NCTC 6375.
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Affiliation(s)
- Preeti Arivaradarajan
- Department of Genetics, Centre for Excellence in Genomic Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai 625 021, India
| | | | - Gunasekaran Paramasamy
- Department of Genetics, Centre for Excellence in Genomic Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai 625 021, India
| | - Sean P Nair
- Department of Microbial Diseases, UCL Eastman Dental Institute, London WC1X 8LD, UK
| | - Elaine Allan
- Department of Microbial Diseases, UCL Eastman Dental Institute, London WC1X 8LD, UK
| | - Peter Mullany
- Department of Microbial Diseases, UCL Eastman Dental Institute, London WC1X 8LD, UK
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Trindade M, van Zyl LJ, Navarro-Fernández J, Abd Elrazak A. Targeted metagenomics as a tool to tap into marine natural product diversity for the discovery and production of drug candidates. Front Microbiol 2015; 6:890. [PMID: 26379658 PMCID: PMC4552006 DOI: 10.3389/fmicb.2015.00890] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 08/17/2015] [Indexed: 11/13/2022] Open
Abstract
Microbial natural products exhibit immense structural diversity and complexity and have captured the attention of researchers for several decades. They have been explored for a wide spectrum of applications, most noteworthy being their prominent role in medicine, and their versatility expands to application as drugs for many diseases. Accessing unexplored environments harboring unique microorganisms is expected to yield novel bioactive metabolites with distinguishing functionalities, which can be supplied to the starved pharmaceutical market. For this purpose the oceans have turned out to be an attractive and productive field. Owing to the enormous biodiversity of marine microorganisms, as well as the growing evidence that many metabolites previously isolated from marine invertebrates and algae are actually produced by their associated bacteria, the interest in marine microorganisms has intensified. Since the majority of the microorganisms are uncultured, metagenomic tools are required to exploit the untapped biochemistry. However, after years of employing metagenomics for marine drug discovery, new drugs are vastly under-represented. While a plethora of natural product biosynthetic genes and clusters are reported, only a minor number of potential therapeutic compounds have resulted through functional metagenomic screening. This review explores specific obstacles that have led to the low success rate. In addition to the typical problems encountered with traditional functional metagenomic-based screens for novel biocatalysts, there are enormous limitations which are particular to drug-like metabolites. We also present how targeted and function-guided strategies, employing modern, and multi-disciplinary approaches have yielded some of the most exciting discoveries attributed to uncultured marine bacteria. These discoveries set the stage for progressing the production of drug candidates from uncultured bacteria for pre-clinical and clinical development.
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Affiliation(s)
- Marla Trindade
- Institute for Microbial Biotechnology and Metagenomics, University of the Western Cape, BellvilleSouth Africa
| | - Leonardo Joaquim van Zyl
- Institute for Microbial Biotechnology and Metagenomics, University of the Western Cape, BellvilleSouth Africa
| | - José Navarro-Fernández
- Institute for Microbial Biotechnology and Metagenomics, University of the Western Cape, BellvilleSouth Africa
- Centro Regional de Hemodonación, Servicio de Hematología y Oncología Médica, Universidad de Murcia, IMIB-Arrixaca, MurciaSpain
| | - Ahmed Abd Elrazak
- Institute for Microbial Biotechnology and Metagenomics, University of the Western Cape, BellvilleSouth Africa
- Botany Department, Faculty of Science, Mansoura University, MansouraEgypt
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Are the Traditional Medical Uses of Muricidae Molluscs Substantiated by Their Pharmacological Properties and Bioactive Compounds? Mar Drugs 2015; 13:5237-75. [PMID: 26295242 PMCID: PMC4557022 DOI: 10.3390/md13085237] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 07/27/2015] [Accepted: 08/07/2015] [Indexed: 12/20/2022] Open
Abstract
Marine molluscs from the family Muricidae hold great potential for development as a source of therapeutically useful compounds. Traditionally known for the production of the ancient dye Tyrian purple, these molluscs also form the basis of some rare traditional medicines that have been used for thousands of years. Whilst these traditional and alternative medicines have not been chemically analysed or tested for efficacy in controlled clinical trials, a significant amount of independent research has documented the biological activity of extracts and compounds from these snails. In particular, Muricidae produce a suite of brominated indoles with anti-inflammatory, anti-cancer and steroidogenic activity, as well as choline esters with muscle-relaxing and pain relieving properties. These compounds could explain some of the traditional uses in wound healing, stomach pain and menstrual problems. However, the principle source of bioactive compounds is from the hypobranchial gland, whilst the shell and operculum are the main source used in most traditional remedies. Thus further research is required to understand this discrepancy and to optimise a quality controlled natural medicine from Muricidae.
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Coughlan LM, Cotter PD, Hill C, Alvarez-Ordóñez A. Biotechnological applications of functional metagenomics in the food and pharmaceutical industries. Front Microbiol 2015; 6:672. [PMID: 26175729 PMCID: PMC4485178 DOI: 10.3389/fmicb.2015.00672] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 06/19/2015] [Indexed: 12/31/2022] Open
Abstract
Microorganisms are found throughout nature, thriving in a vast range of environmental conditions. The majority of them are unculturable or difficult to culture by traditional methods. Metagenomics enables the study of all microorganisms, regardless of whether they can be cultured or not, through the analysis of genomic data obtained directly from an environmental sample, providing knowledge of the species present, and allowing the extraction of information regarding the functionality of microbial communities in their natural habitat. Function-based screenings, following the cloning and expression of metagenomic DNA in a heterologous host, can be applied to the discovery of novel proteins of industrial interest encoded by the genes of previously inaccessible microorganisms. Functional metagenomics has considerable potential in the food and pharmaceutical industries, where it can, for instance, aid (i) the identification of enzymes with desirable technological properties, capable of catalyzing novel reactions or replacing existing chemically synthesized catalysts which may be difficult or expensive to produce, and able to work under a wide range of environmental conditions encountered in food and pharmaceutical processing cycles including extreme conditions of temperature, pH, osmolarity, etc; (ii) the discovery of novel bioactives including antimicrobials active against microorganisms of concern both in food and medical settings; (iii) the investigation of industrial and societal issues such as antibiotic resistance development. This review article summarizes the state-of-the-art functional metagenomic methods available and discusses the potential of functional metagenomic approaches to mine as yet unexplored environments to discover novel genes with biotechnological application in the food and pharmaceutical industries.
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Affiliation(s)
| | - Paul D Cotter
- Teagasc Food Research Centre Cork, Ireland ; Alimentary Pharmabiotic Centre Cork, Ireland
| | - Colin Hill
- Alimentary Pharmabiotic Centre Cork, Ireland ; School of Microbiology, University College Cork Cork, Ireland
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Characterization of a flavin-containing monooxygenase from Corynebacterium glutamicum and its application to production of indigo and indirubin. Biotechnol Lett 2015; 37:1637-44. [DOI: 10.1007/s10529-015-1824-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/23/2015] [Indexed: 10/23/2022]
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Takeshige Y, Egami Y, Wakimoto T, Abe I. Production of indole antibiotics induced by exogenous gene derived from sponge metagenomes. MOLECULAR BIOSYSTEMS 2015; 11:1290-4. [PMID: 25828760 DOI: 10.1039/c5mb00131e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sponge metagenomes are accessible genetic sources containing genes and gene clusters responsible for the biosynthesis of sponge-derived bioactive natural products. In this study, we obtained the clone pDC112, producing turbomycin A and 2,2-di(3-indolyl)-3-indolone, based on the functional screening of the metagenome library derived from the marine sponge Discodermia calyx. The subcloning experiment identified ORF 25, which is homologous to inosine 5'-monophosphate dehydrogenase and required for the production of 2,2-di(3-indolyl)-3-indolone in Escherichia coli.
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Affiliation(s)
- Yuya Takeshige
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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Isolation of oxygenase genes for indigo-forming activity from an artificially polluted soil metagenome by functional screening using Pseudomonas putida strains as hosts. Appl Microbiol Biotechnol 2015; 99:4453-70. [DOI: 10.1007/s00253-014-6322-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 12/08/2014] [Accepted: 12/12/2014] [Indexed: 10/24/2022]
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Sanka Loganathachetti D, Muthuraman S. Biomedical potential of natural products derived through metagenomic approaches. RSC Adv 2015. [DOI: 10.1039/c5ra20116k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Microbes are ubiquitous, irrespective of the environment they thrive in. Only 1% of these are culturable in laboratory. Metagenomics is useful in exploring biomedically important small molecules using culture independent approaches.
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Milshteyn A, Schneider JS, Brady SF. Mining the metabiome: identifying novel natural products from microbial communities. CHEMISTRY & BIOLOGY 2014; 21:1211-23. [PMID: 25237864 PMCID: PMC4171686 DOI: 10.1016/j.chembiol.2014.08.006] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 08/06/2014] [Accepted: 08/08/2014] [Indexed: 12/21/2022]
Abstract
Microbial-derived natural products provide the foundation for most of the chemotherapeutic arsenal available to contemporary medicine. In the face of a dwindling pipeline of new lead structures identified by traditional culturing techniques and an increasing need for new therapeutics, surveys of microbial biosynthetic diversity across environmental metabiomes have revealed enormous reservoirs of as yet untapped natural products chemistry. In this review, we touch on the historical context of microbial natural product discovery and discuss innovations and technological advances that are facilitating culture-dependent and culture-independent access to new chemistry from environmental microbiomes with the goal of reinvigorating the small molecule therapeutics discovery pipeline. We highlight the successful strategies that have emerged and some of the challenges that must be overcome to enable the development of high-throughput methods for natural product discovery from complex microbial communities.
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Affiliation(s)
- Aleksandr Milshteyn
- Laboratory of Genetically Encoded Small Molecules, Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Jessica S Schneider
- Laboratory of Genetically Encoded Small Molecules, Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Sean F Brady
- Laboratory of Genetically Encoded Small Molecules, Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Howard Hughes Medical Institute, Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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de Castro AP, Fernandes GDR, Franco OL. Insights into novel antimicrobial compounds and antibiotic resistance genes from soil metagenomes. Front Microbiol 2014; 5:489. [PMID: 25278933 PMCID: PMC4166954 DOI: 10.3389/fmicb.2014.00489] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 09/01/2014] [Indexed: 11/13/2022] Open
Abstract
In recent years a major worldwide problem has arisen with regard to infectious diseases caused by resistant bacteria. Resistant pathogens are related to high mortality and also to enormous healthcare costs. In this field, cultured microorganisms have been commonly focused in attempts to isolate antibiotic resistance genes or to identify antimicrobial compounds. Although this strategy has been successful in many cases, most of the microbial diversity and related antimicrobial molecules have been completely lost. As an alternative, metagenomics has been used as a reliable approach to reveal the prospective reservoir of antimicrobial compounds and antibiotic resistance genes in the uncultured microbial community that inhabits a number of environments. In this context, this review will focus on resistance genes as well as on novel antibiotics revealed by a metagenomics approach from the soil environment. Biotechnology prospects are also discussed, opening new frontiers for antibiotic development.
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Affiliation(s)
- Alinne P de Castro
- Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco Laboratórios Inova, Campo Grande, Brazil
| | - Gabriel da R Fernandes
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Centro de Analises Proteomicas e Bioquimicas, Universidade Católica de Brasília Brasilia, Brazil
| | - Octávio L Franco
- Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco Laboratórios Inova, Campo Grande, Brazil ; Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Centro de Analises Proteomicas e Bioquimicas, Universidade Católica de Brasília Brasilia, Brazil
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Abstract
Metagenomics deals with the isolation of genetic material directly recovered from environmental samples. Metagenomics as an approach has emerged over the past two decades to elucidate a host of microbial communities inhabiting a specific niche with the goal of understanding their genetic diversity, population structure, and ecological role played by them. A number of new and novel molecules with significant functionalities and applications have been identified through this approach. In fact, many investigators are engaged in this field to unlock the untapped genetic resources with funding from governments sector. The sustainable economic future of modern industrialized societies requires the development of novel molecules, enzymes, processes, products, and applications. Metagenomics can also be applied to solve practical challenges in the field of medicine, agriculture, sustainability, and ecology. Metagenomics promises to provide new molecules and novel enzymes with diverse functions and enhanced features compared to the enzymes from the culturable microorganisms. Besides the application of metagenomics for unlocking novel biocatalysts from nature, it also has found applications in fields as diverse as bioremediation, personalized medicine, xenobiotic metabolism, and so forth.
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41
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Charlop-Powers Z, Milshteyn A, Brady SF. Metagenomic small molecule discovery methods. Curr Opin Microbiol 2014; 19:70-75. [PMID: 25000402 DOI: 10.1016/j.mib.2014.05.021] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 05/10/2014] [Accepted: 05/28/2014] [Indexed: 12/18/2022]
Abstract
Metagenomic approaches to natural product discovery provide the means to harvest bioactive small molecules synthesized by environmental bacteria without the requirement of first culturing these organisms. Advances in sequencing technologies and general metagenomic methods are beginning to provide the tools necessary to unlock the unexplored biosynthetic potential encoded by the genomes of uncultured environmental bacteria. Here, we highlight recent advances in sequence-based and functional-based metagenomic approaches that promise to facilitate antibiotic discovery from diverse environmental microbiomes.
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Affiliation(s)
- Zachary Charlop-Powers
- Laboratory of Genetically Encoded Small Molecules, Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, United States
| | - Aleksandr Milshteyn
- Laboratory of Genetically Encoded Small Molecules, Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, United States
| | - Sean F Brady
- Laboratory of Genetically Encoded Small Molecules, Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, United States.
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42
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Yan X, Tang XX, Chen L, Yi ZW, Fang MJ, Wu Z, Qiu YK. Two new cytotoxic indole alkaloids from a deep-sea sediment derived metagenomic clone. Mar Drugs 2014; 12:2156-63. [PMID: 24717525 PMCID: PMC4012447 DOI: 10.3390/md12042156] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 03/07/2014] [Accepted: 03/10/2014] [Indexed: 11/29/2022] Open
Abstract
Two new indole alkaloids, metagenetriindole A (1) and metagenebiindole A (2), were identified from deep-sea sediment metagenomic clone derived Escherichia coli fermentation broth. The structures of new compounds were elucidated by spectroscopic methods. The two new indole alkaloids demonstrated moderately cytotoxic activity against CNE2, Bel7402 and HT1080 cancer cell lines in vitro.
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Affiliation(s)
- Xia Yan
- Key Laboratory for Chemical Biology of Fujian Province, School of Pharmaceutical Sciences, Xiamen University, South Xiang-An Road, Xiamen 361102, China.
| | - Xi-Xiang Tang
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography State Oceanic Administration, Xiamen 361005, China.
| | - Lin Chen
- Key Laboratory for Chemical Biology of Fujian Province, School of Pharmaceutical Sciences, Xiamen University, South Xiang-An Road, Xiamen 361102, China.
| | - Zhi-Wei Yi
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography State Oceanic Administration, Xiamen 361005, China.
| | - Mei-Juan Fang
- Key Laboratory for Chemical Biology of Fujian Province, School of Pharmaceutical Sciences, Xiamen University, South Xiang-An Road, Xiamen 361102, China.
| | - Zhen Wu
- Key Laboratory for Chemical Biology of Fujian Province, School of Pharmaceutical Sciences, Xiamen University, South Xiang-An Road, Xiamen 361102, China.
| | - Ying-Kun Qiu
- Key Laboratory for Chemical Biology of Fujian Province, School of Pharmaceutical Sciences, Xiamen University, South Xiang-An Road, Xiamen 361102, China.
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44
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Lee MH, Lee SW. Bioprospecting potential of the soil metagenome: novel enzymes and bioactivities. Genomics Inform 2013; 11:114-20. [PMID: 24124406 PMCID: PMC3794083 DOI: 10.5808/gi.2013.11.3.114] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 08/14/2013] [Accepted: 08/20/2013] [Indexed: 11/22/2022] Open
Abstract
The microbial diversity in soil ecosystems is higher than in any other microbial ecosystem. The majority of soil microorganisms has not been characterized, because the dominant members have not been readily culturable on standard cultivation media; therefore, the soil ecosystem is a great reservoir for the discovery of novel microbial enzymes and bioactivities. The soil metagenome, the collective microbial genome, could be cloned and sequenced directly from soils to search for novel microbial resources. This review summarizes the microbial diversity in soils and the efforts to search for microbial resources from the soil metagenome, with more emphasis on the potential of bioprospecting metagenomics and recent discoveries.
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Affiliation(s)
- Myung Hwan Lee
- Department of Applied Biology, Dong-A University, Busan 604-714, Korea
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45
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Benkendorff K. Natural product research in the Australian marine invertebrate Dicathais orbita. Mar Drugs 2013; 11:1370-98. [PMID: 23612370 PMCID: PMC3705410 DOI: 10.3390/md11041370] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 03/04/2013] [Accepted: 03/08/2013] [Indexed: 11/25/2022] Open
Abstract
The predatory marine gastropod Dicathais orbita has been the subject of a significant amount of biological and chemical research over the past five decades. Natural products research on D. orbita includes the isolation and identification of brominated indoles and choline esters as precursors of Tyrian purple, as well as the synthesis of structural analogues, bioactivity testing, biodistributional and biosynthetic studies. Here I also report on how well these compounds conform to Lipinski’s rule of five for druglikeness and their predicted receptor binding and enzyme inhibitor activity. The composition of mycosporine-like amino acids, fatty acids and sterols has also been described in the egg masses of D. orbita. The combination of bioactive compounds produced by D. orbita is of interest for further studies in chemical ecology, as well as for future nutraceutical development. Biological insights into the life history of this species, as well as ongoing research on the gene expression, microbial symbionts and biosynthetic capabilities, should facilitate sustainable production of the bioactive compounds. Knowledge of the phylogeny of D. orbita provides an excellent platform for novel research into the evolution of brominated secondary metabolites in marine molluscs. The range of polarities in the brominated indoles produced by D. orbita has also provided an effective model system used to develop a new method for biodistributional studies. The well characterized suite of chemical reactions that generate Tyrian purple, coupled with an in depth knowledge of the ecology, anatomy and genetics of D. orbita provide a good foundation for ongoing natural products research.
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Affiliation(s)
- Kirsten Benkendorff
- Marine Ecology Research Center, School of Environment, Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW 2480, Australia.
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46
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Cobb RE, Luo Y, Freestone T, Zhao H. Drug Discovery and Development via Synthetic Biology. Synth Biol (Oxf) 2013. [DOI: 10.1016/b978-0-12-394430-6.00010-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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47
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He R, Wakimoto T, Egami Y, Kenmoku H, Ito T, Asakawa Y, Abe I. Heterologously expressed β-hydroxyl fatty acids from a metagenomic library of a marine sponge. Bioorg Med Chem Lett 2012; 22:7322-5. [DOI: 10.1016/j.bmcl.2012.10.082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 10/16/2012] [Accepted: 10/17/2012] [Indexed: 10/27/2022]
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49
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Abe T, Kukita A, Akiyama K, Naito T, Uemura D. Isolation and Structure of a Novel Biindole Pigment Substituted with an Ethyl Group from a Metagenomic Library Derived from the Marine SpongeHalichondria okadai. CHEM LETT 2012. [DOI: 10.1246/cl.2012.728] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Takahiro Abe
- Department of Chemistry, Faculty of Science, Kanagawa University
| | - Akira Kukita
- Department of Chemistry, Faculty of Science, Kanagawa University
| | - Kiyotaka Akiyama
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology
| | - Takayuki Naito
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology
| | - Daisuke Uemura
- Department of Chemistry, Faculty of Science, Kanagawa University
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50
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Li H, Zhang Q, Li S, Zhu Y, Zhang G, Zhang H, Tian X, Zhang S, Ju J, Zhang C. Identification and characterization of xiamycin A and oxiamycin gene cluster reveals an oxidative cyclization strategy tailoring indolosesquiterpene biosynthesis. J Am Chem Soc 2012; 134:8996-9005. [PMID: 22591327 DOI: 10.1021/ja303004g] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Xiamycin A (XMA) and oxiamycin (OXM) are bacterial indolosesquiterpenes featuring rare pentacyclic ring systems and are isolated from a marine-derived Streptomyces sp. SCSIO 02999. The putative biosynthetic gene cluster for XMA/OXM was identified by a partial genome sequencing approach. Eighteen genes were proposed to be involved in XMA/OXM biosynthesis, including five genes for terpene synthesis via a non-mevalonate pathway, eight genes encoding oxidoreductases, and five genes for regulation and resistance. Targeted disruptions of 13 genes within the xia gene cluster were carried out to probe their encoded functions in XMA/OXM biosynthesis. The disruption of xiaK, encoding an aromatic ring hydroxylase, led to a mutant producing indosespene and a minor amount of XMA. Feeding of indosespene to XMA/OXM nonproducing mutants revealed indosespene as a common precursor for XMA/OXM biosynthesis. Most notably, the flavin dependent oxygenase XiaI was biochemically characterized in vitro to convert indosespene to XMA, revealing an unusual oxidative cyclization strategy tailoring indolosesquiterpene biosynthesis.
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Affiliation(s)
- Huixian Li
- CAS Key Laboratory of Marine Bio-resources Sustainable Utilization, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
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