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González A, Fullaondo A, Odriozola A. Techniques, procedures, and applications in microbiome analysis. ADVANCES IN GENETICS 2024; 111:81-115. [PMID: 38908906 DOI: 10.1016/bs.adgen.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/24/2024]
Abstract
Microbiota is a complex community of microorganisms living in a defined environment. Until the 20th century, knowledge of microbiota was partial, as the techniques available for their characterization were primarily based on bacteriological culture. In the last twenty years, the development of DNA sequencing technologies, multi-omics, and bioinformatics has expanded our understanding of microorganisms. We have moved from mainly considering them isolated disease-causing agents to recognizing the microbiota as an essential component of host biology. These techniques have shown that the microbiome plays essential roles in various host phenotypes, influencing development, physiology, reproduction, and evolution. This chapter provides researchers with a summary of the primary concepts, sample collection, experimental techniques, and bioinformatics analysis commonly used in microbiome research. The main features, applications in microbiome studies, and their advantages and limitations are included in each section.
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Affiliation(s)
- Adriana González
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country (UPV/EHU), Leioa, Spain.
| | - Asier Fullaondo
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Adrián Odriozola
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country (UPV/EHU), Leioa, Spain
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2
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Rafiq M, Hassan N, Rehman M, Hayat M, Nadeem G, Hassan F, Iqbal N, Ali H, Zada S, Kang Y, Sajjad W, Jamal M. Challenges and Approaches of Culturing the Unculturable Archaea. BIOLOGY 2023; 12:1499. [PMID: 38132325 PMCID: PMC10740628 DOI: 10.3390/biology12121499] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/06/2023] [Accepted: 11/14/2023] [Indexed: 12/23/2023]
Abstract
Since Carl Woese's discovery of archaea as a third domain of life, numerous archaeal species have been discovered, yet archaeal diversity is poorly characterized. Culturing archaea is complicated, but several queries about archaeal cell biology, evolution, physiology, and diversity need to be solved by culturing and culture-dependent techniques. Increasing interest in demand for innovative culturing methods has led to various technological and methodological advances. The current review explains frequent hurdles hindering uncultured archaea isolation and discusses features for more archaeal cultivation. This review also discusses successful strategies and available media for archaeal culturing, which might be helpful for future culturing practices.
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Affiliation(s)
- Muhammad Rafiq
- Department of Microbiology, Faculty of Life Sciences and Informatics, Balochistan University of IT, Engineering and Management Sciences, Quetta 87100, Pakistan
- FF Institute (Huzhou) Co., Ltd., Huzhou 313000, China
| | - Noor Hassan
- Industrial Biotechnology Division, National Institute for Biotechnology and Genetic Engineering-College, Pakistan Institute of Engineering and Applied Sciences, Islamabad 44000, Pakistan
| | - Maliha Rehman
- Department of Microbiology, Faculty of Life Sciences and Informatics, Balochistan University of IT, Engineering and Management Sciences, Quetta 87100, Pakistan
| | - Muhammad Hayat
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Jinan 266101, China
| | - Gullasht Nadeem
- Department of Microbiology, Faculty of Life Sciences and Informatics, Balochistan University of IT, Engineering and Management Sciences, Quetta 87100, Pakistan
| | - Farwa Hassan
- Industrial Biotechnology Division, National Institute for Biotechnology and Genetic Engineering-College, Pakistan Institute of Engineering and Applied Sciences, Islamabad 44000, Pakistan
| | - Naveed Iqbal
- Department of Biotechnology, Faculty of Life Sciences and Informatics, Balochistan University of IT, Engineering and Management Sciences, Quetta 87100, Pakistan
- The Department of Paediatrics and Child Health, Aga Khan University, Karachi 74800, Pakistan
| | - Hazrat Ali
- Industrial Biotechnology Division, National Institute for Biotechnology and Genetic Engineering-College, Pakistan Institute of Engineering and Applied Sciences, Islamabad 44000, Pakistan
| | - Sahib Zada
- Guangzhou Institute of Energy Conservation, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Yingqian Kang
- Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education of Guizhou, Guiyang 550025, China
- Key Laboratory of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang 550025, China
| | - Wasim Sajjad
- Department of Biological Sciences, National University of Medical Sciences, Rawalpindi 46000, Pakistan
| | - Muhsin Jamal
- Department of Microbiology, Abdul Wali Khan University, Garden Campus, Mardan 23200, Pakistan
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3
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Schultz J, Modolon F, Peixoto RS, Rosado AS. Shedding light on the composition of extreme microbial dark matter: alternative approaches for culturing extremophiles. Front Microbiol 2023; 14:1167718. [PMID: 37333658 PMCID: PMC10272570 DOI: 10.3389/fmicb.2023.1167718] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 05/09/2023] [Indexed: 06/20/2023] Open
Abstract
More than 20,000 species of prokaryotes (less than 1% of the estimated number of Earth's microbial species) have been described thus far. However, the vast majority of microbes that inhabit extreme environments remain uncultured and this group is termed "microbial dark matter." Little is known regarding the ecological functions and biotechnological potential of these underexplored extremophiles, thus representing a vast untapped and uncharacterized biological resource. Advances in microbial cultivation approaches are key for a detailed and comprehensive characterization of the roles of these microbes in shaping the environment and, ultimately, for their biotechnological exploitation, such as for extremophile-derived bioproducts (extremozymes, secondary metabolites, CRISPR Cas systems, and pigments, among others), astrobiology, and space exploration. Additional efforts to enhance culturable diversity are required due to the challenges imposed by extreme culturing and plating conditions. In this review, we summarize methods and technologies used to recover the microbial diversity of extreme environments, while discussing the advantages and disadvantages associated with each of these approaches. Additionally, this review describes alternative culturing strategies to retrieve novel taxa with their unknown genes, metabolisms, and ecological roles, with the ultimate goal of increasing the yields of more efficient bio-based products. This review thus summarizes the strategies used to unveil the hidden diversity of the microbiome of extreme environments and discusses the directions for future studies of microbial dark matter and its potential applications in biotechnology and astrobiology.
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Affiliation(s)
- Júnia Schultz
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Flúvio Modolon
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Laboratory of Molecular Microbial Ecology, Institute of Microbiology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Raquel Silva Peixoto
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Alexandre Soares Rosado
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
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Kapinusova G, Lopez Marin MA, Uhlik O. Reaching unreachables: Obstacles and successes of microbial cultivation and their reasons. Front Microbiol 2023; 14:1089630. [PMID: 36960281 PMCID: PMC10027941 DOI: 10.3389/fmicb.2023.1089630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/10/2023] [Indexed: 03/09/2023] Open
Abstract
In terms of the number and diversity of living units, the prokaryotic empire is the most represented form of life on Earth, and yet it is still to a significant degree shrouded in darkness. This microbial "dark matter" hides a great deal of potential in terms of phylogenetically or metabolically diverse microorganisms, and thus it is important to acquire them in pure culture. However, do we know what microorganisms really need for their growth, and what the obstacles are to the cultivation of previously unidentified taxa? Here we review common and sometimes unexpected requirements of environmental microorganisms, especially soil-harbored bacteria, needed for their replication and cultivation. These requirements include resuscitation stimuli, physical and chemical factors aiding cultivation, growth factors, and co-cultivation in a laboratory and natural microbial neighborhood.
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Affiliation(s)
| | | | - Ondrej Uhlik
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology, Prague, Czechia
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Abstract
The vast majority of environmental microbes have not yet been cultured, and most of the knowledge on coral-associated microbes (CAMs) has been generated from amplicon sequencing and metagenomes. However, exploring cultured CAMs is key for a detailed and comprehensive characterization of the roles of these microbes in shaping coral health and, ultimately, for their biotechnological use as, for example, coral probiotics and other natural products. Here, the strategies and technologies that have been used to access cultured CAMs are presented, while advantages and disadvantages associated with each of these strategies are discussed. We highlight the existing gaps and potential improvements in culture-dependent methodologies, indicating several possible alternatives (including culturomics and in situ diffusion devices) that could be applied to retrieve the CAM "dark matter" (i.e., the currently undescribed CAMs). This study provides the most comprehensive synthesis of the methodologies used to recover the cultured coral microbiome to date and draws suggestions for the development of the next generation of CAM culturomics.
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Cario A, Larzillière M, Nguyen O, Alain K, Marre S. High-Pressure Microfluidics for Ultra-Fast Microbial Phenotyping. Front Microbiol 2022; 13:866681. [PMID: 35677901 PMCID: PMC9168469 DOI: 10.3389/fmicb.2022.866681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 04/27/2022] [Indexed: 01/09/2023] Open
Abstract
Here, we present a novel methodology based on high-pressure microfluidics to rapidly perform temperature-based phenotyping of microbial strains from deep-sea environments. The main advantage concerns the multiple on-chip temperature conditions that can be achieved in a single experiment at pressures representative of the deep-sea, overcoming the conventional limitations of large-scale batch metal reactors to conduct fast screening investigations. We monitored the growth of the model strain Thermococcus barophilus over 40 temperature and pressure conditions, without any decompression, in only 1 week, whereas it takes weeks or months with conventional approaches. The results are later compared with data from the literature. An additional example is also shown for a hydrogenotrophic methanogen strain (Methanothermococcus thermolithotrophicus), demonstrating the robustness of the methodology. These microfluidic tools can be used in laboratories to accelerate characterizations of new isolated species, changing the widely accepted paradigm that high-pressure microbiology experiments are time-consuming.
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Affiliation(s)
- Anaïs Cario
- Univ. Bordeaux, CNRS, Bordeaux INP, ICMCB, UMR 5026, Pessac, France
- *Correspondence: Anaïs Cario,
| | - Marina Larzillière
- Univ. Bordeaux, CNRS, Bordeaux INP, ICMCB, UMR 5026, Pessac, France
- CNRS, Univ. Brest, Ifremer, IRP 1211 MicrobSea, Unité de Biologie et Ecologie des Ecosystèmes Marins Profonds BEEP, IUEM, Plouzané, France
| | - Olivier Nguyen
- Univ. Bordeaux, CNRS, Bordeaux INP, ICMCB, UMR 5026, Pessac, France
| | - Karine Alain
- CNRS, Univ. Brest, Ifremer, IRP 1211 MicrobSea, Unité de Biologie et Ecologie des Ecosystèmes Marins Profonds BEEP, IUEM, Plouzané, France
| | - Samuel Marre
- Univ. Bordeaux, CNRS, Bordeaux INP, ICMCB, UMR 5026, Pessac, France
- Samuel Marre,
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Two-Dimensional Cell Separation: a High-Throughput Approach to Enhance the Culturability of Bacterial Cells from Environmental Samples. Microbiol Spectr 2022; 10:e0000722. [PMID: 35467387 PMCID: PMC9248899 DOI: 10.1128/spectrum.00007-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Culture-independent sequence data from various environmental samples have revealed an immense microbial diversity of environmental, clinical, and industrial importance that has not yet been cultured. Cultivation is imperative to validate findings emerging from cultivation-independent molecular data and exploit the isolated organisms for biotechnological purposes. Efforts have been made to boost the cultivability of microbes from environmental samples by use of a range of techniques and instrumentation. The manuscript presents a novel yet simple and innovative approach to improving the cultivability of natural microorganisms without sophisticated instrumentation. By employing gradient centrifugation combined with serial dilution (“two-dimensional cell separation”), significantly higher numbers of genera (>2-fold higher) and species (>3-fold higher) were isolated from environmental samples, including soil, anaerobic sludge, and landfill leachate, than from using serial dilution alone. This simple and robust protocol can be modified for any environment and culture medium and provides access to untapped microbial diversity. IMPORTANCE In the manuscript, we have developed a novel yet simple and innovative approach to improving the cultivability of natural microorganisms without sophisticated instrumentation. The method used gradient centrifugation combined with serial dilution (two-dimensional cell separation) to improve taxum recovery from samples. This simple and robust protocol can be modified for any environment and culture medium and provides access to untapped microbial diversity. This approach can be incorporated with less labor and complexity in laboratories with minimal instrumentation. As cultivation is a workflow that is well suited to lower-resource microbiology labs, we believe improvements in cultivability can increase opportunities for scientific collaborations between low-resource labs and groups focused on high-resource cultivation-independent methodologies.
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Dat TTH, Steinert G, Cuc NTK, Smidt H, Sipkema D. Bacteria Cultivated From Sponges and Bacteria Not Yet Cultivated From Sponges-A Review. Front Microbiol 2021; 12:737925. [PMID: 34867854 PMCID: PMC8634882 DOI: 10.3389/fmicb.2021.737925] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 10/18/2021] [Indexed: 12/21/2022] Open
Abstract
The application of high-throughput microbial community profiling as well as "omics" approaches unveiled high diversity and host-specificity of bacteria associated with marine sponges, which are renowned for their wide range of bioactive natural products. However, exploration and exploitation of bioactive compounds from sponge-associated bacteria have been limited because the majority of the bacteria remains recalcitrant to cultivation. In this review, we (i) discuss recent/novel cultivation techniques that have been used to isolate sponge-associated bacteria, (ii) provide an overview of bacteria isolated from sponges until 2017 and the associated culture conditions and identify the bacteria not yet cultured from sponges, and (iii) outline promising cultivation strategies for cultivating the uncultivated majority of bacteria from sponges in the future. Despite intensive cultivation attempts, the diversity of bacteria obtained through cultivation remains much lower than that seen through cultivation-independent methods, which is particularly noticeable for those taxa that were previously marked as "sponge-specific" and "sponge-enriched." This poses an urgent need for more efficient cultivation methods. Refining cultivation media and conditions based on information obtained from metagenomic datasets and cultivation under simulated natural conditions are the most promising strategies to isolate the most wanted sponge-associated bacteria.
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Affiliation(s)
- Ton That Huu Dat
- Mientrung Institute for Scientific Research, Vietnam Academy of Science and Technology, Hanoi, Vietnam
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Georg Steinert
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Nguyen Thi Kim Cuc
- Institute of Marine Biochemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Detmer Sipkema
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
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Rämä T, Quandt CA. Improving Fungal Cultivability for Natural Products Discovery. Front Microbiol 2021; 12:706044. [PMID: 34603232 PMCID: PMC8481835 DOI: 10.3389/fmicb.2021.706044] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 08/23/2021] [Indexed: 11/13/2022] Open
Abstract
The pool of fungal secondary metabolites can be extended by activating silent gene clusters of cultured strains or by using sensitive biological assays that detect metabolites missed by analytical methods. Alternatively, or in parallel with the first approach, one can increase the diversity of existing culture collections to improve the access to new natural products. This review focuses on the latter approach of screening previously uncultured fungi for chemodiversity. Both strategies have been practiced since the early days of fungal biodiscovery, yet relatively little has been done to overcome the challenge of cultivability of as-yet-uncultivated fungi. Whereas earlier cultivability studies using media formulations and biological assays to scrutinize fungal growth and associated factors were actively conducted, the application of modern omics methods remains limited to test how to culture the fungal dark matter and recalcitrant groups of described fungi. This review discusses the development of techniques to increase the cultivability of filamentous fungi that include culture media formulations and the utilization of known chemical growth factors, in situ culturing and current synthetic biology approaches that build upon knowledge from sequenced genomes. We list more than 100 growth factors, i.e., molecules, biological or physical factors that have been demonstrated to induce spore germination as well as tens of inducers of mycelial growth. We review culturing conditions that can be successfully manipulated for growth of fungi and visit recent information from omics methods to discuss the metabolic basis of cultivability. Earlier work has demonstrated the power of co-culturing fungi with their host, other microorganisms or their exudates to increase their cultivability. Co-culturing of two or more organisms is also a strategy used today for increasing cultivability. However, fungi possess an increased risk for cross-contaminations between isolates in existing in situ or microfluidics culturing devices. Technological improvements for culturing fungi are discussed in the review. We emphasize that improving the cultivability of fungi remains a relevant strategy in drug discovery and underline the importance of ecological and taxonomic knowledge in culture-dependent drug discovery. Combining traditional and omics techniques such as single cell or metagenome sequencing opens up a new era in the study of growth factors of hundreds of thousands of fungal species with high drug discovery potential.
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Affiliation(s)
- Teppo Rämä
- Marbio, Norwegian College of Fishery Science, University of Tromsø – The Arctic University of Norway, Tromsø, Norway
| | - C. Alisha Quandt
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Boulder, CO, United States
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Prakash O, Parmar M, Vaijanapurkar M, Rale V, Shouche YS. Recent trend, biases and limitations of cultivation-based diversity studies of microbes. FEMS Microbiol Lett 2021; 368:6359716. [PMID: 34459476 DOI: 10.1093/femsle/fnab118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 08/27/2021] [Indexed: 12/22/2022] Open
Abstract
The current study attempts to analyze recent trends, biases and limitations of cultivation-based microbial diversity studies based on published, novel species in the past 6 years in the International Journal of Systematic and Evolutionary Microbiology (IJSEM), an official publication of the International Committee on Systematics of Prokaryotes (ICSP) and the Bacteriology and Applied Microbiology (BAM) Division of the International Union of Microbiological Societies (IUMS). IJSEM deals with taxa that have validly published names under the International Code of Nomenclature of Prokaryotes (ICNP). All the relevant publications from the last 6 years were retrieved, sorted and analyzed to get the answers to What is the current rate of novel species description? Which country has contributed substantially and which phyla represented better in culturable diversity studies? What are the current limitations? Published data for the past 6 years indicate that 500-900 novel species are reported annually. China, Korea, Germany, UK, India and the USA are at the forefront while contributions from other nations are meager. Despite the recent development in culturomics tools the dominance of Proteobacteria, Bacteroidetes and Actinobacteria are still prevalent in cultivation, while the representation of archaea, obligate anaerobes, microaerophiles, synergistic symbionts, aerotolerant and other fastidious microbes is poor. Single strain-based taxonomic descriptions prevail and emphasis on objective-based cultivation for biotechnological and environmental significance is not yet conspicuous.
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Affiliation(s)
- Om Prakash
- National Centre for Microbial Resource (NCMR), National Centre for Cell Science (NCCS), Pune 411007, Maharashtra, India
| | - Mrinalini Parmar
- National Centre for Microbial Resource (NCMR), National Centre for Cell Science (NCCS), Pune 411007, Maharashtra, India
| | - Manali Vaijanapurkar
- National Centre for Microbial Resource (NCMR), National Centre for Cell Science (NCCS), Pune 411007, Maharashtra, India.,Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Pune-412115, Maharashtra, India
| | - Vinay Rale
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Pune-412115, Maharashtra, India
| | - Yogesh S Shouche
- National Centre for Microbial Resource (NCMR), National Centre for Cell Science (NCCS), Pune 411007, Maharashtra, India
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Li X, Zhao H, Chen X. Screening of Marine Bioactive Antimicrobial Compounds for Plant Pathogens. Mar Drugs 2021; 19:69. [PMID: 33525648 PMCID: PMC7912171 DOI: 10.3390/md19020069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 01/21/2021] [Accepted: 01/25/2021] [Indexed: 01/09/2023] Open
Abstract
Plant diseases have been threatening food production. Controlling plant pathogens has become an important strategy to ensure food security. Although chemical control is an effective disease control strategy, its application is limited by many problems, such as environmental impact and pathogen resistance. In order to overcome these problems, it is necessary to develop more chemical reagents with new functional mechanisms. Due to their special living environment, marine organisms have produced a variety of bioactive compounds with novel structures, which have the potential to develop new fungicides. In the past two decades, screening marine bioactive compounds to inhibit plant pathogens has been a hot topic. In this review, we summarize the screening methods of marine active substances from plant pathogens, the identification of marine active substances from different sources, and the structure and antibacterial mechanism of marine active natural products. Finally, the application prospect of marine bioactive substances in plant disease control was prospected.
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Affiliation(s)
- Xiaohui Li
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315832, China; (X.L.); (H.Z.)
| | - Hejing Zhao
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315832, China; (X.L.); (H.Z.)
| | - Xiaolin Chen
- State Key Laboratory of Agricultural Microbiology and Provincial Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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Alkayyali T, Pope E, Wheatley SK, Cartmell C, Haltli B, Kerr RG, Ahmadi A. Development of a microbe domestication pod (MD Pod) for in situ cultivation of micro-encapsulated marine bacteria. Biotechnol Bioeng 2020; 118:1166-1176. [PMID: 33241862 DOI: 10.1002/bit.27633] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 11/01/2020] [Accepted: 11/20/2020] [Indexed: 11/10/2022]
Abstract
Microbial marine natural products hold significant potential for the discovery of new bioactive therapeutics such as antibiotics. Unfortunately, this discovery is hindered by the inability to culture the majority of microbes using traditional laboratory approaches. While many new methods have been developed to increase cultivability, a high-throughput in situ incubation chamber capable of simultaneously isolating individual microbes while allowing cellular communication has not previously been reported. Development of such a device would expedite the discovery of new microbial taxa and, thus, facilitate access to their associated natural products. In this study, this concept is achieved by the development of a new device termed by the authors as the microbe domestication (MD) Pod. The MD Pod enables single-cell cultivation by isolating marine bacterial cells in agarose microbeads produced using microfluidics, while allowing potential transmission of chemical signals between cells during in situ incubation in a chamber, or "Pod," that is deployed in the environment. The design of the MD Pod was optimized to ensure the use of biocompatible materials, allow for simple assembly in a field setting, and maintain sterility throughout incubation. The encapsulation process was designed to ensure that the viability of marine sediment bacteria was not adversely impacted by the encapsulation process. The process was validated using representative bacteria isolated from temperate marine sediment samples: Marinomonas polaris, Psychrobacter aquimaris, and Bacillus licheniformis. The overall process appeared to promote metabolic activity of most representative species. Thus, microfluidic encapsulation of marine bacteria and subsequent in situ incubation in the MD Pod is expected to accelerate marine natural products discovery by increasing the cultivability of marine bacteria.
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Affiliation(s)
- Tartela Alkayyali
- Faculty of Sustainable Design Engineering, University of Prince Edward Island, Prince Edward Island, Canada
| | - Emily Pope
- Departments of Biomedical Sciences, University of Prince Edward Island, Prince Edward Island, Canada
| | - Sydney K Wheatley
- Faculty of Sustainable Design Engineering, University of Prince Edward Island, Prince Edward Island, Canada
| | - Christopher Cartmell
- Departments of Chemistry, University of Prince Edward Island, Prince Edward Island, Canada
| | - Bradley Haltli
- Departments of Biomedical Sciences, University of Prince Edward Island, Prince Edward Island, Canada.,Nautilus Biosciences Croda, Prince Edward Island, Canada
| | - Russell G Kerr
- Departments of Biomedical Sciences, University of Prince Edward Island, Prince Edward Island, Canada.,Departments of Chemistry, University of Prince Edward Island, Prince Edward Island, Canada.,Nautilus Biosciences Croda, Prince Edward Island, Canada
| | - Ali Ahmadi
- Faculty of Sustainable Design Engineering, University of Prince Edward Island, Prince Edward Island, Canada
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Ultra-high throughput screening for novel protease specificities. Methods Enzymol 2020. [PMID: 32943144 DOI: 10.1016/bs.mie.2020.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The screening of large libraries of enzyme variants remains an essential tool in evolving biocatalysts toward improved properties for applications in medicine, chemistry, and a broad variety of other fields. Over the last decades, the technology for conducting systematic screens of arrayed members of a library of enzyme variants has made great strides in terms of increasing throughput and reducing assay volume. Here, we describe in detail an alternative to arrayed analysis, which is a screen based on density shifts in result of changed enzyme function, which allows highly parallelized screening. Specifically, we link changes in protease substrate specificity in vivo to the production of an alternative reporter protein, catalase. Depending on the catalase expression level, microcolonies of library bacteria with active protease variants contained in polymeric droplets generate an oxygen bubble, which causes a density shift in the droplet and enables it to float.
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Karnachuk OV, Lukina AP, Kadnikov VV, Sherbakova VA, Beletsky AV, Mardanov AV, Ravin NV. Targeted isolation based on metagenome‐assembled genomes reveals a phylogenetically distinct group of thermophilic spirochetes from deep biosphere. Environ Microbiol 2020; 23:3585-3598. [DOI: 10.1111/1462-2920.15218] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/18/2020] [Accepted: 08/27/2020] [Indexed: 12/22/2022]
Affiliation(s)
| | | | - Vitaly V. Kadnikov
- Institute of Bioengineering Research Center of Biotechnology of the Russian Academy of Sciences Moscow 119071 Russia
| | - Viktoria A. Sherbakova
- Skryabin Institute of Biochemistry and Physiology of Microorganisms Federal Research Center ‘Pushchino Scientific Center for Biological Research, Russian Academy of Sciences’ Pushchino Moscow 142290 Russia
| | - Alexey V. Beletsky
- Institute of Bioengineering Research Center of Biotechnology of the Russian Academy of Sciences Moscow 119071 Russia
| | - Andrey V. Mardanov
- Institute of Bioengineering Research Center of Biotechnology of the Russian Academy of Sciences Moscow 119071 Russia
| | - Nikolai V. Ravin
- Institute of Bioengineering Research Center of Biotechnology of the Russian Academy of Sciences Moscow 119071 Russia
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15
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Modolon F, Barno AR, Villela HDM, Peixoto RS. Ecological and biotechnological importance of secondary metabolites produced by coral-associated bacteria. J Appl Microbiol 2020; 129:1441-1457. [PMID: 32627318 DOI: 10.1111/jam.14766] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/20/2020] [Accepted: 06/28/2020] [Indexed: 12/16/2022]
Abstract
Symbiotic relationships between corals and their associated micro-organisms are essential to maintain host homeostasis. Coral-associated bacteria (CAB) can have different beneficial roles in the coral metaorganism, such as metabolizing essential nutrients for the coral host and protecting the coral from pathogens. Many CAB exert these functions via secondary metabolites, which include antibacterial, antifouling, antitumour, antiparasitic and antiviral compounds. This review describes how analysis of CAB has led to the discovery of secondary metabolites with potential biotechnological applications. The most commonly found types of secondary metabolites, antimicrobial and antibiofilm compounds, are emphasized and described. Recently developed methods that can be applied to enhance the culturing of CAB from shallow-water reefs and the less-studied deep-sea coral reefs are also discussed. Last, we suggest how the combined use of meta-omics and innovative growth-diffusion techniques can vastly improve the discovery of novel compounds in coral environments.
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Affiliation(s)
- F Modolon
- Department of Microbiology, Paulo de Góes Microbiology Institute, Federal University of Rio De Janeiro, Rio de Janeiro, RJ, Brazil
| | - A R Barno
- Department of Microbiology, Paulo de Góes Microbiology Institute, Federal University of Rio De Janeiro, Rio de Janeiro, RJ, Brazil
| | - H D M Villela
- Department of Microbiology, Paulo de Góes Microbiology Institute, Federal University of Rio De Janeiro, Rio de Janeiro, RJ, Brazil
| | - R S Peixoto
- Department of Microbiology, Paulo de Góes Microbiology Institute, Federal University of Rio De Janeiro, Rio de Janeiro, RJ, Brazil.,IMAM-AquaRio - Rio de Janeiro Aquarium Research Center, Rio de Janeiro, RJ, Brazil
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16
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Sun Y, Liu Y, Pan J, Wang F, Li M. Perspectives on Cultivation Strategies of Archaea. MICROBIAL ECOLOGY 2020; 79:770-784. [PMID: 31432245 DOI: 10.1007/s00248-019-01422-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/01/2019] [Indexed: 06/10/2023]
Abstract
Archaea have been recognized as a major domain of life since the 1970s and occupy a key position in the tree of life. Recent advances in culture-independent approaches have greatly accelerated the research son Archaea. However, many hypotheses concerning the diversity, physiology, and evolution of archaea are waiting to be confirmed by culture-base experiments. Consequently, archaeal isolates are in great demand. On the other hand, traditional approaches of archaeal cultivation are rarely successful and require urgent improvement. Here, we review the current practices and applicable microbial cultivation techniques, to inform on potential strategies that could improve archaeal cultivation in the future. We first summarize the current knowledge on archaeal diversity, with an emphasis on cultivated and uncultivated lineages pertinent to future research. Possible causes for the low success rate of the current cultivation practices are then discussed to propose future improvements. Finally, innovative insights for archaeal cultivation are described, including (1) medium refinement for selective cultivation based on the genetic and transcriptional information; (2) consideration of the up-to-date archaeal culturing skills; and (3) application of multiple cultivation techniques, such as co-culture, direct interspecies electron transfer (DIET), single-cell isolation, high-throughput culturing (HTC), and simulation of the natural habitat. Improved cultivation efforts should allow successful isolation of as yet uncultured archaea, contributing to the much-needed physiological investigation of archaea.
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Affiliation(s)
- Yihua Sun
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
| | - Yang Liu
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
| | - Jie Pan
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
| | - Fengping Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
- State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Meng Li
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China.
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17
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Cross KL, Campbell JH, Balachandran M, Campbell AG, Cooper SJ, Griffen A, Heaton M, Joshi S, Klingeman D, Leys E, Yang Z, Parks JM, Podar M. Targeted isolation and cultivation of uncultivated bacteria by reverse genomics. Nat Biotechnol 2019; 37:1314-1321. [PMID: 31570900 PMCID: PMC6858544 DOI: 10.1038/s41587-019-0260-6] [Citation(s) in RCA: 171] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 08/15/2019] [Indexed: 12/16/2022]
Abstract
Most microorganisms from all taxonomic levels are uncultured. Single-cell
genomes and metagenomes continue to increase the known diversity of
Bacteria and Archaea, but while
‘omics can be used to infer physiological or ecological roles for species
in a community, most of those hypothetical roles remain unvalidated. Here we
report an approach to capture specific microorganisms from complex communities
into pure cultures using genome-informed antibody engineering. We apply our
reverse genomics approach to isolate and sequence single cells and to cultivate
three different species-level lineages of human oral Saccharibacteria/TM7. Using
our pure cultures we show that all three saccharibacteria species are epibionts
of diverse Actinobacteria. We also isolate and cultivate human
oral SR1 bacteria, which are members of a lineage of previously uncultured
bacteria. Reverse-genomics-enabled cultivation of microorganisms can be applied
to any species from any environment and has the potential to unlock the
isolation, cultivation and characterization of species from as-yet-uncultured
branches of the microbial tree of life.
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Affiliation(s)
- Karissa L Cross
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Department of Microbiology, University of Tennessee, Knoxville, TN, USA
| | - James H Campbell
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Department of Natural Sciences, Northwest Missouri State University, Maryville, MO, USA
| | | | - Alisha G Campbell
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Genome Science and Technology Program, University of Tennessee, Knoxville, TN, USA.,Department of Natural Sciences, Northwest Missouri State University, Maryville, MO, USA
| | - Sarah J Cooper
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Genome Science and Technology Program, University of Tennessee, Knoxville, TN, USA
| | - Ann Griffen
- College of Dentistry, The Ohio State University, Columbus, OH, USA
| | | | - Snehal Joshi
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Dawn Klingeman
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Eugene Leys
- College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Zamin Yang
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Jerry M Parks
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Genome Science and Technology Program, University of Tennessee, Knoxville, TN, USA
| | - Mircea Podar
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA. .,Department of Microbiology, University of Tennessee, Knoxville, TN, USA. .,Genome Science and Technology Program, University of Tennessee, Knoxville, TN, USA.
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18
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Hahn MW, Koll U, Schmidt J. Isolation and Cultivation of Bacteria. ADVANCES IN ENVIRONMENTAL MICROBIOLOGY 2019. [DOI: 10.1007/978-3-030-16775-2_10] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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19
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Feng XW, Ding WP, Xiong LY, Guo L, Sun JM, Xiao P. Recent Advancements in Intestinal Microbiota Analyses: A Review for Non-Microbiologists. Curr Med Sci 2018; 38:949-961. [PMID: 30536055 DOI: 10.1007/s11596-018-1969-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Revised: 06/12/2018] [Indexed: 02/06/2023]
Abstract
Microbial constituents naturally inhabiting the gastrointestinal tract may influence the homeostasis of the gut environment. The presence or overabundance of some bacterial taxa has been reported to be associated with complex diseases, and the metabolites of certain bacteria may contribute to diverse disorders by influencing signaling pathways. Therefore, the study of gut microbial population has emerged as a crucial field and a new potential area of clinical significance. Advances in the methods of microbiota analysis have shed light upon the details including species diversity, microfloral activities as well as the entire gut microbiota. Nevertheless, comprehensive reviews on this subject are still limited. For elucidating the appropriate selection strategy of the methods to address a particular research question, we comprehensively reviewed the continuously improving technologies, classical to newly developed, and dissected their relative advantages and drawbacks. In addition, aiming at the rapidly advancing next-generation sequencing, we enumerated the improvements in mainstream platforms and made the horizontal and vertical comparison among them. Additionally, we demonstrated the four main -omics methods, which may provide further mechanistic insights into the role of microbiota, to propel phylotyping analysis to functional analysis.
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Affiliation(s)
- Xiao-Wei Feng
- Department of Psychiatry, Wuhan Youfu Hospital, Wuhan, 430050, China
| | - Wen-Ping Ding
- Department of Ultrasound, Wuhan Women and Children's Health Care Center, Wuhan, 430016, China
| | - Ling-Yun Xiong
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Liang Guo
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Jia-Ming Sun
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Peng Xiao
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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20
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Chen L, Hu JS, Xu JL, Shao CL, Wang GY. Biological and Chemical Diversity of Ascidian-Associated Microorganisms. Mar Drugs 2018; 16:md16100362. [PMID: 30275404 PMCID: PMC6212887 DOI: 10.3390/md16100362] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 09/23/2018] [Accepted: 09/27/2018] [Indexed: 11/16/2022] Open
Abstract
Ascidians are a class of sessile filter-feeding invertebrates, that provide unique and fertile niches harboring various microorganisms, such as bacteria, actinobacteria, cyanobacteria and fungi. Over 1000 natural products, including alkaloids, cyclic peptides, and polyketides, have been isolated from them, which display diverse properties, such as antibacterial, antifungal, antitumor, and anti-inflammatory activities. Strikingly, direct evidence has confirmed that ~8% of natural products from ascidians are actually produced by symbiotic microorganisms. In this review, we present 150 natural products from microorganisms associated with ascidians that have been reported up to 2017.
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Affiliation(s)
- Lei Chen
- Department of Bioengineering, School of Marine Science and Technology, Harbin Institute of Technology, Weihai 264209, China.
| | - Jin-Shuang Hu
- Department of Bioengineering, School of Marine Science and Technology, Harbin Institute of Technology, Weihai 264209, China.
| | - Jia-Lei Xu
- Department of Bioengineering, School of Marine Science and Technology, Harbin Institute of Technology, Weihai 264209, China.
| | - Chang-Lun Shao
- Laboratory of Marine Drugs, The Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China.
| | - Guang-Yu Wang
- Department of Bioengineering, School of Marine Science and Technology, Harbin Institute of Technology, Weihai 264209, China.
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21
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Qu W, Lin D, Zhang Z, Di W, Gao B, Zeng R. Metagenomics Investigation of Agarlytic Genes and Genomes in Mangrove Sediments in China: A Potential Repertory for Carbohydrate-Active Enzymes. Front Microbiol 2018; 9:1864. [PMID: 30177916 PMCID: PMC6109693 DOI: 10.3389/fmicb.2018.01864] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/25/2018] [Indexed: 12/31/2022] Open
Abstract
Monosaccharides and oligosaccharides produced by agarose degradation exhibit potential in the fields of bioenergy, medicine, and cosmetics. Mangrove sediments (MGSs) provide a special environment to enrich enzymes for agarose degradation. However, representative investigations of the agarlytic genes in MGSs have been rarely reported. In this study, agarlytic genes in MGSs were researched in detail from the aspects of diversity, abundance, activity, and location through deep metagenomics sequencing. Functional genes in MGSs were usually incomplete but were shown as results, which could cause virtually high number of results in previous studies because multiple fragmented sequences could originate from the same genes. In our work, only complete and nonredundant (CNR) genes were analyzed to avoid virtually high amount of the results. The number of CNR agarlytic genes in our datasets was significantly higher than that in the datasets of previous studies. Twenty-one recombinant agarases with agarose-degrading activity were detected using heterologous expression based on numerous complete open-reading frames, which are rarely obtained in metagenomics sequencing of samples with complex microbial communities, such as MGSs. Aga2, which had the highest crude enzyme activity among the 21 recombinant agarases, was further purified and subjected to enzymatic characterization. With its high agarose-degrading activity, resistance to temperature changes and chemical agents, Aga2 could be a suitable option for industrial production. The agarase ratio with signal peptides to that without signal peptides in our MGS datasets was lower than that of other reported agarases. Six draft genomes, namely, Clusters 1-6, were recovered from the datasets. The taxonomic annotation of these genomes revealed that Clusters 1, 3, 5, and 6 were annotated as Desulfuromonas sp., Treponema sp., Ignavibacteriales spp., and Polyangiaceae spp., respectively. Meanwhile, Clusters 2 and 4 were potential new species. All these genomes were first reported and found to have abilities of degrading various important polysaccharides. The metabolic pathway of agarose in Cluster 4 was also speculated. Our results showed the capacity and activity of agarases in the MGS microbiome, and MGSs exert potential as a repertory for mining not only agarlytic genes but also almost all genes of the carbohydrate-active enzyme family.
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Affiliation(s)
- Wu Qu
- School of Life Sciences, Xiamen University, Xiamen, China
| | - Dan Lin
- Novogene Bioinformatics Technology Co. Ltd., Tianjin, China
| | - Zhouhao Zhang
- Novogene Bioinformatics Technology Co. Ltd., Tianjin, China
| | - Wenjie Di
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, China
| | - Boliang Gao
- School of Life Sciences, Xiamen University, Xiamen, China
| | - Runying Zeng
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, China.,Key Laboratory of Marine Genetic Resources, Xiamen, China
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22
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Oueriaghli N, Castro DJ, Llamas I, Béjar V, Martínez-Checa F. Study of Bacterial Community Composition and Correlation of Environmental Variables in Rambla Salada, a Hypersaline Environment in South-Eastern Spain. Front Microbiol 2018; 9:1377. [PMID: 29977233 PMCID: PMC6021518 DOI: 10.3389/fmicb.2018.01377] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Accepted: 06/06/2018] [Indexed: 12/03/2022] Open
Abstract
We studied the bacterial community in Rambla Salada in three different sampling sites and in three different seasons and the effect of salinity, oxygen, and pH. All sites samples had high diversity and richness (Rr > 30). The diversity indexes and the analysis of dendrograms obtained by DGGE fingerprint after applying Pearson's and Dice's coefficient showed a strong influence of sampling season. The Pareto-Lorenz (PL) curves and Fo analysis indicated that the microbial communities were balanced and despite the changing environmental conditions, they can preserve their functionality. The main phyla detected by DGGE were Bacteroidetes (39.73%), Proteobacteria (28.43%), Firmicutes (8.23%), and Cyanobacteria (5.14%). The majority of the sequences corresponding to uncultured bacteria belonged to Bacteroidetes phylum. Within Proteobacteria, the main genera detected were Halothiobacillus and Roseovarius. The environmental factors which influenced the community in a higher degree were the salinity and oxygen. The bacteria belonging to Bacteroidetes and Proteobacteria were positively influenced by salinity. Nevertheless, bacteria related to Alpha- and Betaproteobacteria classes and phylum Firmicutes showed a positive correlation with oxygen and pH but negative with salinity. The phylum Cyanobacteria were less influenced by the environmental variables. The bacterial community composition of Rambla Salada was also studied by dilution-to-extinction technique. Using this method, 354 microorganisms were isolated. The 16S sequences of 61 isolates showed that the diversity was very different to those obtained by DGGE and with those obtained previously by using classic culture techniques. The taxa identified by dilution-to-extinction were Proteobacteria (81.92%), Firmicutes (11.30%), Actinobacteria (4.52%), and Bacteroidetes (2.26%) phyla with Gammaproteobacteria as predominant class (65.7%). The main genera were: Marinobacter (38.85%), Halomonas (20.2%), and Bacillus (11.2%). Nine of the 61 identified bacteria showed less than 97% sequence identity with validly described species and may well represent new taxa. The number of bacteria in different samples, locations, and seasons were calculated by CARD-FISH, ranging from 54.3 to 78.9% of the total prokaryotic population. In conclusion, the dilution-to-extinction technique could be a complementary method to classical culture based method, but neither gets to cultivate the major taxa detected by DGGE. The bacterial community was influenced significantly by the physico-chemical parameters (specially the salinity and oxygen), the location and the season of sampling.
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Affiliation(s)
- Nahid Oueriaghli
- Microbial Exopolysacharide Research Group, Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain
| | - David J. Castro
- Microbial Exopolysacharide Research Group, Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain
- Institute of Biotechnology, University of Granada, Granada, Spain
| | - Inmaculada Llamas
- Microbial Exopolysacharide Research Group, Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain
- Institute of Biotechnology, University of Granada, Granada, Spain
| | - Victoria Béjar
- Microbial Exopolysacharide Research Group, Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain
- Institute of Biotechnology, University of Granada, Granada, Spain
| | - Fernando Martínez-Checa
- Microbial Exopolysacharide Research Group, Department of Microbiology, Faculty of Pharmacy, University of Granada, Granada, Spain
- Institute of Biotechnology, University of Granada, Granada, Spain
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23
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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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24
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Esteves AIS, Amer N, Nguyen M, Thomas T. Sample Processing Impacts the Viability and Cultivability of the Sponge Microbiome. Front Microbiol 2016; 7:499. [PMID: 27242673 PMCID: PMC4876369 DOI: 10.3389/fmicb.2016.00499] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 03/28/2016] [Indexed: 12/17/2022] Open
Abstract
Sponges host complex microbial communities of recognized ecological and biotechnological importance. Extensive cultivation efforts have been made to isolate sponge bacteria, but most still elude cultivation. To identify the bottlenecks of sponge bacterial cultivation, we combined high-throughput 16S rRNA gene sequencing with a variety of cultivation media and incubation conditions. We aimed to determine the extent to which sample processing and cultivation conditions can impact bacterial viability and recovery in culture. We isolated 325 sponge bacteria from six specimens of Cymbastela concentrica and three specimens of Scopalina sp. These isolates were distributed over 37 different genera and 47 operational taxonomic units (defined at 97% 16S rRNA gene sequence identity). The cultivable bacterial community was highly specific to its sponge host and different media compositions yielded distinct microbial isolates. Around 97% of the isolates could be detected in the original sponge and represented a large but highly variable proportion (0.5–92% total abundance, depending on sponge species) of viable bacteria obtained after sample processing, as determined by propidium monoazide selective DNA modification of compromised cells. Our results show that the most abundant viable bacteria are also the most predominant groups found in cultivation, reflecting, to some extent, the relative abundances of the viable bacterial community, rather than the overall community estimated by direct molecular approaches. Cultivation is therefore shaped not only by the growth conditions provided, but also by the different cell viabilities of the bacteria that constitute the cultivation inoculum. These observations highlight the need to perform experiments to assess each method of sample processing for its accurate representation of the actual in situ bacterial community and its yield of viable cells.
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Affiliation(s)
- Ana I S Esteves
- Centre for Marine Bio-Innovation, School of Biological, Earth and Environmental Sciences, The University of New South Wales Kensington, NSW, Australia
| | - Nimra Amer
- Centre for Marine Bio-Innovation, School of Biological, Earth and Environmental Sciences, The University of New South Wales Kensington, NSW, Australia
| | - Mary Nguyen
- Centre for Marine Bio-Innovation, School of Biological, Earth and Environmental Sciences, The University of New South Wales Kensington, NSW, Australia
| | - Torsten Thomas
- Centre for Marine Bio-Innovation, School of Biological, Earth and Environmental Sciences, The University of New South Wales Kensington, NSW, Australia
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25
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Tanaka Y, Benno Y. Application of a single-colony coculture technique to the isolation of hitherto unculturable gut bacteria. Microbiol Immunol 2015; 59:63-70. [PMID: 25510436 DOI: 10.1111/1348-0421.12220] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Revised: 12/01/2014] [Accepted: 12/11/2014] [Indexed: 11/27/2022]
Abstract
Molecular studies have led to postulation of a relationship between gut microbiota and certain diseases. However, because studies of hitherto uncultured species in vivo are essential for characterizing the biology and pathogenic properties of gut bacteria, techniques for culturing and isolating such bacteria must be developed. Here, a technique is described that partially overcomes the obstacles that prevent detection of interbacterial communication in vitro and are thus responsible for the failure to culture certain bacterial species. For this purpose, a ring with a membrane filter at the bottom was designed and a relatively simple nutrient medium was used instead of conventional media. Gut bacteria were cocultivated in soft agar separated by the membrane filter to simulate interbacterial communication in vitro. Use of this soft agar coculture technique led to the successful isolation of hitherto uncultured bacteria and the demonstration of multistage interbacterial communication among gut bacteria in vitro. Cultivation and isolation of single colonies of bacteria that require other bacteria for growth will enhance efforts to better understand the physiological and pathogenic roles of gut microbiota.
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Affiliation(s)
- Yoshiki Tanaka
- Biofermin Kobe Research Institute, Biofermin Pharmaceutical, 7-3-4 Higashi-machi, Ibukidai, Nishi-ku, Kobe, Hyogo, 651-2242; Benno Laboratory, RIKEN Innovation Center, 2-1, Hirosawa, Wako, Saitama, 351-0198, Japan
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26
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Hollister EB, Brooks JP, Gentry TJ. Bioinformation and ’Omic Approaches for Characterization of Environmental Microorganisms. Environ Microbiol 2015. [DOI: 10.1016/b978-0-12-394626-3.00021-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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27
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Cultivation-based multiplex phenotyping of human gut microbiota allows targeted recovery of previously uncultured bacteria. Nat Commun 2014; 5:4714. [PMID: 25163406 DOI: 10.1038/ncomms5714] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 07/15/2014] [Indexed: 12/12/2022] Open
Abstract
The human gut microbiota is linked to a variety of human health issues and implicated in antibiotic resistance gene dissemination. Most of these associations rely on culture-independent methods, since it is commonly believed that gut microbiota cannot be easily or sufficiently cultured. Here, we show that carefully designed conditions enable cultivation of a representative proportion of human gut bacteria, enabling rapid multiplex phenotypic profiling. We use this approach to determine the phylogenetic distribution of antibiotic tolerance phenotypes for 16 antibiotics in the human gut microbiota. Based on the phenotypic mapping, we tailor antibiotic combinations to specifically select for previously uncultivated bacteria. Utilizing this method we cultivate and sequence the genomes of four isolates, one of which apparently belongs to the genus Oscillibacter; uncultivated Oscillibacter strains have been previously found to be anti-correlated with Crohn's disease.
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Richards MA, Cassen V, Heavner BD, Ajami NE, Herrmann A, Simeonidis E, Price ND. MediaDB: a database of microbial growth conditions in defined media. PLoS One 2014; 9:e103548. [PMID: 25098325 PMCID: PMC4123892 DOI: 10.1371/journal.pone.0103548] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 06/30/2014] [Indexed: 01/24/2023] Open
Abstract
Isolating pure microbial cultures and cultivating them in the laboratory on defined media is used to more fully characterize the metabolism and physiology of organisms. However, identifying an appropriate growth medium for a novel isolate remains a challenging task. Even organisms with sequenced and annotated genomes can be difficult to grow, despite our ability to build genome-scale metabolic networks that connect genomic data with metabolic function. The scientific literature is scattered with information about defined growth media used successfully for cultivating a wide variety of organisms, but to date there exists no centralized repository to inform efforts to cultivate less characterized organisms by bridging the gap between genomic data and compound composition for growth media. Here we present MediaDB, a manually curated database of defined media that have been used for cultivating organisms with sequenced genomes, with an emphasis on organisms with metabolic network models. The database is accessible online, can be queried by keyword searches or downloaded in its entirety, and can generate exportable individual media formulation files. The data assembled in MediaDB facilitate comparative studies of organism growth media, serve as a starting point for formulating novel growth media, and contribute to formulating media for in silico investigation of metabolic networks. MediaDB is freely available for public use at https://mediadb.systemsbiology.net.
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Affiliation(s)
- Matthew A. Richards
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Institute for Systems Biology, Seattle, Washington, United States of America
| | - Victor Cassen
- Institute for Systems Biology, Seattle, Washington, United States of America
| | - Benjamin D. Heavner
- Institute for Systems Biology, Seattle, Washington, United States of America
| | - Nassim E. Ajami
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Andrea Herrmann
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Evangelos Simeonidis
- Institute for Systems Biology, Seattle, Washington, United States of America
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Nathan D. Price
- Institute for Systems Biology, Seattle, Washington, United States of America
- * E-mail:
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Mehta CM, Palni U, Franke-Whittle IH, Sharma AK. Compost: its role, mechanism and impact on reducing soil-borne plant diseases. WASTE MANAGEMENT (NEW YORK, N.Y.) 2014; 34:607-22. [PMID: 24373678 DOI: 10.1016/j.wasman.2013.11.012] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 11/28/2013] [Accepted: 11/28/2013] [Indexed: 05/14/2023]
Abstract
Soil-borne plant pathogens are responsible for causing many crop plant diseases, resulting in significant economic losses. Compost application to agricultural fields is an excellent natural approach, which can be taken to fight against plant pathogens. The application of organic waste products is also an environmentally friendly alternative to chemical use, which unfortunately is the most common approach in agriculture today. This review analyses pioneering and recent compost research, and also the mechanisms and mode of action of compost microbial communities for reducing the activity of plant pathogens in agricultural crops. In addition, an approach for improving the quality of composts through the microbial communities already present in the compost is presented. Future agricultural practices will almost definitely require integrated research strategies to help combat plant diseases.
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Affiliation(s)
- C M Mehta
- Department of Biological Sciences, College of Basic Science and Humanities, G. B. P. U. A. & T. Pantnagar, U.S. Nagar, Uttarakhand, India; Department of Botany, D.S.B. Campus, Kumaun University Nainital, Uttarakhand, India
| | - Uma Palni
- Department of Botany, D.S.B. Campus, Kumaun University Nainital, Uttarakhand, India
| | - I H Franke-Whittle
- Leopold-Franzens University, Institute of Microbiology, Technikerstraße 25, 6020 Innsbruck, Austria
| | - A K Sharma
- Department of Biological Sciences, College of Basic Science and Humanities, G. B. P. U. A. & T. Pantnagar, U.S. Nagar, Uttarakhand, India.
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Brugère JF, Mihajlovski A, Missaoui M, Peyret P. Tools for stools: the challenge of assessing human intestinal microbiota using molecular diagnostics. Expert Rev Mol Diagn 2014; 9:353-65. [DOI: 10.1586/erm.09.16] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Akondi K, Lakshmi V. Emerging Trends in Genomic Approaches for Microbial Bioprospecting. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2013; 17:61-70. [DOI: 10.1089/omi.2012.0082] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- K.B. Akondi
- Department of Applied Microbiology, Sri Padmavati Women's University, Tirupati, India
| | - V.V. Lakshmi
- Department of Applied Microbiology, Sri Padmavati Women's University, Tirupati, India
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Cultivation of unculturable soil bacteria. Trends Biotechnol 2012; 30:475-84. [PMID: 22770837 DOI: 10.1016/j.tibtech.2012.05.007] [Citation(s) in RCA: 242] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 05/29/2012] [Accepted: 05/31/2012] [Indexed: 11/24/2022]
Abstract
Despite the abundance of bacterial species in soil, more than 99% of these species cannot be cultured by traditional techniques. In addition, the less than 1% of bacteria that can be cultured are not representative of the total phylogenetic diversity. Hence, identifying novel species and their new functions is still an important task for all microbiologists. Cultivating techniques have played an important role in identifying new species but are still low-throughput processes. This review discusses the issues surrounding cultivation, including achievements, limitations, challenges, and future directions.
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Abstract
The bacteria that can be grown in the laboratory are only a small fraction of the total diversity that exists in nature. At all levels of bacterial phylogeny, uncultured clades that do not grow on standard media are playing critical roles in cycling carbon, nitrogen, and other elements, synthesizing novel natural products, and impacting the surrounding organisms and environment. While molecular techniques, such as metagenomic sequencing, can provide some information independent of our ability to culture these organisms, it is essentially impossible to learn new gene and pathway functions from pure sequence data. A true understanding of the physiology of these bacteria and their roles in ecology, host health, and natural product production requires their cultivation in the laboratory. Recent advances in growing these species include coculture with other bacteria, recreating the environment in the laboratory, and combining these approaches with microcultivation technology to increase throughput and access rare species. These studies are unraveling the molecular mechanisms of unculturability and are identifying growth factors that promote the growth of previously unculturable organisms. This minireview summarizes the recent discoveries in this area and discusses the potential future of the field.
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Ferrari BC, Winsley TJ, Bergquist PL, Van Dorst J. Flow cytometry in environmental microbiology: a rapid approach for the isolation of single cells for advanced molecular biology analysis. Methods Mol Biol 2012; 881:3-26. [PMID: 22639208 DOI: 10.1007/978-1-61779-827-6_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The isolation and subsequent characterization of microbial cells from within environmental samples is a difficult process. Flow cytometry and cell sorting, when combined with the application of fluorescent probes, have the capability for the detection and separation of diverse microbial populations from within complex mixtures. The isolation of single cells allows for downstream investigations towards system-level characterization of unknown Bacterial Phyla to occur. We describe here the combination of fluorescent in situ hybridization and cell sorting for the detection and isolation of Candidate Division TM7 bacteria from an enriched soil sample. The result is the isolation of rare cells suitable for advanced molecular analysis including whole genome amplification and high-throughput pyrosequencing.
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Affiliation(s)
- Belinda C Ferrari
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Randwick, NSW, Australia.
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Georgiades K, Merhej V, Raoult D. The influence of rickettsiologists on post-modern microbiology. Front Cell Infect Microbiol 2011; 1:8. [PMID: 22919574 PMCID: PMC3417371 DOI: 10.3389/fcimb.2011.00008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 10/10/2011] [Indexed: 11/29/2022] Open
Abstract
Many of the definitions in microbiology are currently false. We have reviewed the great denominations of microbiology and attempted to free microorganisms from the theories of the twentieth century. The presence of compartmentation and a nucleoid in Planctomycetes clearly calls into question the accuracy of the definitions of eukaryotes and prokaryotes. Archaea are viewed as prokaryotes resembling bacteria. However, the name archaea, suggesting an archaic origin of lifestyle, is inconsistent with the lifestyle of this family. Viruses are defined as small, filterable infectious agents, but giant viruses challenge the size criteria used for the definition of a virus. Pathogenicity does not require the acquisition of virulence factors (except for toxins), and in many cases, gene loss is significantly inked to the emergence of virulence. Species classification based on 16S rRNA is useless for taxonomic purposes of human pathogens, as a 2% divergence would classify all Rickettsiae within the same species and would not identify bacteria specialized for mammal infection. The use of metagenomics helps us to understand evolution and physiology by elucidating the structure, function, and interactions of the major microbial communities, but it neglects the minority populations. Finally, Darwin’s descent with modification theory, as represented by the tree of life, no longer matches our current genomic knowledge because genomics has revealed the occurrence of de novo-created genes and the mosaic structure of genomes, the Rhizome of life is therefore more appropriate.
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Affiliation(s)
- Kalliopi Georgiades
- Unité de Recherche en Maladies Infectieuses Tropical Emergentes, CNRS-IRD UMR 6236-198, Université de la Méditerranée Marseille, France.
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Fujii K, Kuwahara A, Nakamura K, Yamashita Y. Development of a simple cultivation method for isolating hitherto-uncultured cellulase-producing microbes. Appl Microbiol Biotechnol 2011; 91:1183-92. [DOI: 10.1007/s00253-011-3376-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 05/02/2011] [Accepted: 05/03/2011] [Indexed: 11/30/2022]
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Tiwari K, Gupta RK. Rare actinomycetes: a potential storehouse for novel antibiotics. Crit Rev Biotechnol 2011; 32:108-32. [DOI: 10.3109/07388551.2011.562482] [Citation(s) in RCA: 182] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Multiple approaches to enhance the cultivability of bacteria associated with the marine sponge Haliclona (gellius) sp. Appl Environ Microbiol 2011; 77:2130-40. [PMID: 21296954 DOI: 10.1128/aem.01203-10] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Three methods were examined to cultivate bacteria associated with the marine sponge Haliclona (gellius) sp.: agar plate cultures, liquid cultures, and floating filter cultures. A variety of oligotrophic media were employed, including media with aqueous and organic sponge extracts, bacterial signal molecules, and siderophores. More than 3,900 isolates were analyzed, and 205 operational taxonomic units (OTUs) were identified. Media containing low concentrations of mucin or a mixture of peptone and starch were most successful for the isolation of diversity, while the commonly used marine broth did not result in a high diversity among isolates. The addition of antibiotics generally led to a reduced diversity on plates but yielded different bacteria than other media. In addition, diversity patterns of isolates from agar plates, liquid cultures, and floating filters were significantly different. Almost 89% of all isolates were Alphaproteobacteria; however, members of phyla that are less commonly encountered in cultivation studies, such as Planctomycetes, Verrucomicrobia, and Deltaproteobacteria, were isolated as well. The sponge-associated bacteria were categorized into three different groups. The first group represented OTUs that were also obtained in a clone library from previously analyzed sponge tissue (group 1). Furthermore, we distinguished OTUs that were obtained from sponge tissue (in a previous study) but not from sponge isolates (group 2), and there were also OTUs that were not obtained from sponge tissue but were obtained from sponge isolates (group 3). The 17 OTUs categorized into group 1 represented 10 to 14% of all bacterial OTUs that were present in a large clone library previously generated from Haliclona (gellius) sp. sponge tissue, which is higher than previously reported cultivability scores for sponge-associated bacteria. Six of these 17 OTUs were not obtained from agar plates, which underlines that the use of multiple cultivation methods is worthwhile to increase the diversity of the cultivable microorganisms from sponges.
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Joint I, Mühling M, Querellou J. Culturing marine bacteria - an essential prerequisite for biodiscovery. Microb Biotechnol 2010; 3:564-75. [PMID: 21255353 PMCID: PMC3815769 DOI: 10.1111/j.1751-7915.2010.00188.x] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The potential for using marine microbes for biodiscovery is severely limited by the lack of laboratory cultures. It is a long-standing observation that standard microbiological techniques only isolate a very small proportion of the wide diversity of microbes that are known in natural environments from DNA sequences. A number of explanations are reviewed. The process of establishing laboratory cultures may destroy any cell-to-cell communication that occurs between organisms in the natural environment and that are vital for growth. Bacteria probably grow as consortia in the sea and reliance on other bacteria for essential nutrients and substrates is not possible with standard microbiological approaches. Such interactions should be considered when designing programmes for the isolation of marine microbes. The benefits of novel technologies for manipulating cells are reviewed, including single cell encapsulation in gel micro-droplets. Although novel technologies offer benefits for bringing previously uncultured microbes into laboratory culture, many useful bacteria can still be isolated using variations of plating techniques. Results are summarized for a study to culture bacteria from a long-term observatory station in the English Channel. Bacterial biodiversity in this assemblage has recently been characterized using high-throughput sequencing techniques. Although Alphaproteobacteria dominated the natural bacterial assemblage throughout the year, Gammaproteobacteria were the most frequent group isolated by plating techniques. The use of different gelling agents and the addition of ammonium to seawater-based agar did lead to the isolation of a higher proportion of Alphaproteobacteria. Variation in medium composition was also able to increase the recovery of other groups of particular interest for biodiscovery, such as Actinobacteria.
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Affiliation(s)
- Ian Joint
- Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3DH, UK.
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40
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Abstract
Over the last few decades, advances in cultivation-independent methods have significantly contributed to our understanding of microbial diversity and community composition in the environment. At the same time, cultivation-dependent methods have thrived, and the growing number of organisms obtained thereby have allowed for detailed studies of their physiology and genetics. Still, most microorganisms are recalcitrant to cultivation. This review not only conveys current knowledge about different isolation and cultivation strategies but also discusses what implications can be drawn from pure culture work for studies in microbial ecology. Specifically, in the light of single-cell individuality and genome heterogeneity, it becomes important to evaluate population-wide measurements carefully. An overview of various approaches in microbial ecology is given, and the cell as a central unit for understanding processes on a community level is discussed.
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Affiliation(s)
- Karsten Zengler
- Bioengineering Department, University of California, San Diego, La Jolla, California 92093, USA.
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41
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Nunes da Rocha U, Van Overbeek L, Van Elsas JD. Exploration of hitherto-uncultured bacteria from the rhizosphere. FEMS Microbiol Ecol 2009; 69:313-28. [DOI: 10.1111/j.1574-6941.2009.00702.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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42
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Alain K, Querellou J. Cultivating the uncultured: limits, advances and future challenges. Extremophiles 2009; 13:583-94. [PMID: 19548063 DOI: 10.1007/s00792-009-0261-3] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Accepted: 06/04/2009] [Indexed: 10/20/2022]
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43
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Bergquist PL, Hardiman EM, Ferrari BC, Winsley T. Applications of flow cytometry in environmental microbiology and biotechnology. Extremophiles 2009; 13:389-401. [PMID: 19301090 DOI: 10.1007/s00792-009-0236-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Accepted: 02/26/2009] [Indexed: 10/21/2022]
Abstract
Flow cytometry (FCM) is a technique for counting, examining and sorting microscopic particles suspended in a stream of fluid. It uses the principles of light scattering, light excitation and the emission from fluorescent molecules to generate specific multiparameter data from particles and cells. The cells are hydrodynamically focussed in a sheath solution before being intercepted by a focused light source provided by a laser. FCM has been used primarily in medical applications but is being used increasingly for the examination of individual cells from environmental samples. It has found uses in the isolation of both culturable and hitherto non-culturable bacteria present infrequently in environmental samples using appropriate growth conditions. FCM lends itself to high-throughput applications in directed evolution for the analysis of single cells or cell populations carrying mutant genes. It is also suitable for encapsulation studies where individual bacteria are compartmentalised with substrate in water-in-oil-in-water emulsions or with individual genes in transcriptional/translational mixtures for the production of mutant enzymes. The sensitivity of the technique has allowed the examination of gene optimisation by a procedure known as random or neutral drift where screening and selection is based on the retention of some predetermined level of activity through multiple rounds of mutagenesis.
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Affiliation(s)
- Peter L Bergquist
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, Sydney, NSW, 2109, Australia.
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Walser M, Leibundgut RM, Pellaux R, Panke S, Held M. Isolation of monoclonal microcarriers colonized by fluorescent E. coli. Cytometry A 2008; 73:788-98. [PMID: 18561199 DOI: 10.1002/cyto.a.20597] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Microencapsulation gains increasing importance for processing of bacterial libraries and especially in high-throughput (HT) environments where >10(6) samples per day are studied. As a rule, a one-to-one relationship between an individual cell and analytical results is of key importance. Ideally, each microcarrier would therefore contain exactly one cell or colony. However, synthesis of larger numbers of capsules containing exactly one cell is not feasible as cells are randomly distributed during carrier-production. The dilemma is that high dilution conditions will yield a satisfactory degree of monoclonality, but also a very large fraction of empty compartments, whereas distribution under low dilution generates unacceptable numbers of polyclonal compartments for whose removal no satisfactory technologies exist. Hydrogel carriers with a volume of 35 nL were used as growth compartments for individual microbial colonies. E. coli cells expressing green fluorescent protein (GFP) were encapsulated at low dilution thereby intentionally producing a considerable amount of polyclonal microcarrieres. Empty and polyclonal microcarriers were then removed from the desired monoclonal fraction by a COPAS Plus particle analyzer. The results were compared with model predictions in order to investigate possible limitations in the analysis and sorting of monoclonal microcarriers by COPAS. Fluorescent E. coli cells (GFP) distributed randomly throughout the microcarrier population. Cells were successfully propagated to colonies in the microcarriers and enriched to 95% monoclonality by a COAPS sorter. Enrichment-efficiency was found to mainly depend on the colony diameter. With increasing colony size two contrary effects were observed: First, improved sorting efficiency due to increased fluorescence intensity and therefore higher detection efficiency, and second, deterioration of sorting efficiency due to occlusion occurring in polyclonal carriers. The combination of microencapsulation under low dilution conditions followed by HT sorting procedures is an efficient way for isolating larger amount of monoclonal carriers from bacterial libraries while concomitantly keeping the amounts of empty carriers at a moderate level.
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Affiliation(s)
- Marcel Walser
- ETH Zurich, Institute of Process Engineering, BioProcess Laboratory, Universitätsstr. 6/CAB H88, CH-8092 Zurich, Switzerland
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45
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Bull AT, Stach JE. Marine actinobacteria: new opportunities for natural product search and discovery. Trends Microbiol 2007; 15:491-9. [DOI: 10.1016/j.tim.2007.10.004] [Citation(s) in RCA: 282] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Revised: 08/09/2007] [Accepted: 10/25/2007] [Indexed: 11/15/2022]
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46
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Affiliation(s)
- Dominica Nichols
- Department of Biology, Northeastern University, Boston, MA, USA.
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47
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Lauro FM, Bartlett DH. Prokaryotic lifestyles in deep sea habitats. Extremophiles 2007; 12:15-25. [PMID: 17225926 DOI: 10.1007/s00792-006-0059-5] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Accepted: 12/10/2006] [Indexed: 11/25/2022]
Abstract
Gradients of physicochemical factors influence the growth and survival of life in deep-sea environments. Insights into the characteristics of deep marine prokaryotes has greatly benefited from recent progress in whole genome and metagenome sequence analyses. Here we review the current state-of-the-art of deep-sea microbial genomics. Ongoing and future genome-enabled studies will allow for a better understanding of deep-sea evolution, physiology, biochemistry, community structure and nutrient cycling.
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Affiliation(s)
- Federico M Lauro
- Scripps Institution of Oceanography, Center for Marine Biotechnology and Biomedicine, Marine Biology Research Division, University of California, 8750 Biological Grade, San Diego, La Jolla, CA 92093-0202, USA
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48
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Affiliation(s)
- Carlos Pedrós-Alió
- Department of Marine Biology and Oceanography, Institut de Ciències del Mar, CMIMA-CSIC, Barcelona E-08003, Spain.
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49
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Van Lanen SG, Shen B. Microbial genomics for the improvement of natural product discovery. Curr Opin Microbiol 2006; 9:252-60. [PMID: 16651020 DOI: 10.1016/j.mib.2006.04.002] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Accepted: 04/20/2006] [Indexed: 10/24/2022]
Abstract
The quest for the discovery of novel natural products has entered a new chapter with the enormous wealth of genetic data that is now available. This information has been exploited by using whole-genome sequence mining to uncover cryptic pathways, or biosynthetic pathways for previously undetected metabolites. Alternatively, using known paradigms for secondary metabolite biosynthesis, genetic information has been 'fished out' of DNA libraries resulting in the discovery of new natural products and isolation of gene clusters for known metabolites. Novel natural products have been discovered by expressing genetic data from uncultured organisms or difficult-to-manipulate strains in heterologous hosts. Furthermore, improvements in heterologous expression have not only helped to identify gene clusters but have also made it easier to manipulate these genes in order to generate new compounds. Finally, and perhaps the most crucial aspect of the efficient and prosperous use of the abundance of genetic information, novel enzyme chemistry continues to be discovered, which has aided our understanding of how natural products are biosynthesized de novo, and enabled us to rework the current paradigms for natural product biosynthesis.
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Affiliation(s)
- Steven G Van Lanen
- School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, WI 53705, USA
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