1
|
Maroudas-Sklare N, Goren N, Yochelis S, Jung G, Keren N, Paltiel Y. Probing the design principles of photosynthetic systems through fluorescence noise measurement. Sci Rep 2024; 14:13877. [PMID: 38880795 DOI: 10.1038/s41598-024-64068-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 06/05/2024] [Indexed: 06/18/2024] Open
Abstract
Elucidating the energetic processes which govern photosynthesis, the engine of life on earth, are an essential goal both for fundamental research and for cutting-edge biotechnological applications. Fluorescent signal of photosynthetic markers has long been utilised in this endeavour. In this research we demonstrate the use of fluorescent noise analysis to reveal further layers of intricacy in photosynthetic energy transfer. While noise is a common tool analysing dynamics in physics and engineering, its application in biology has thus far been limited. Here, a distinct behaviour in photosynthetic pigments across various chemical and biological environments is measured. These changes seem to elucidate quantum effects governing the generation of oxidative radicals. Although our method offers insights, it is important to note that the interpretation should be further validated expertly to support as conclusive theory. This innovative method is simple, non-invasive, and immediate, making it a promising tool to uncover further, more complex energetic events in photosynthesis, with potential uses in environmental monitoring, agriculture, and food-tech.
Collapse
Affiliation(s)
- Naama Maroudas-Sklare
- Department of Applied Physics, Hebrew University of Jerusalem, 91904, Jerusalem, Israel
- Department of Plant & Environmental Sciences, The Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Naama Goren
- Department of Applied Physics, Hebrew University of Jerusalem, 91904, Jerusalem, Israel
| | - Shira Yochelis
- Department of Applied Physics, Hebrew University of Jerusalem, 91904, Jerusalem, Israel
| | - Grzegorz Jung
- Department of Physics, Ben Gurion University of the Negev, 84105, Beer Sheva, Israel
- Instytut Fizyki PAN, 02668, Warszawa, Poland
| | - Nir Keren
- Department of Plant & Environmental Sciences, The Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yossi Paltiel
- Department of Applied Physics, Hebrew University of Jerusalem, 91904, Jerusalem, Israel.
| |
Collapse
|
2
|
Baunach M, Guljamow A, Miguel-Gordo M, Dittmann E. Harnessing the potential: advances in cyanobacterial natural product research and biotechnology. Nat Prod Rep 2024; 41:347-369. [PMID: 38088806 DOI: 10.1039/d3np00045a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
Covering: 2000 to 2023Cyanobacteria produce a variety of bioactive natural products that can pose a threat to humans and animals as environmental toxins, but also have potential for or inspire pharmaceutical use. As oxygenic phototrophs, cyanobacteria furthermore hold great promise for sustainable biotechnology. Yet, the necessary tools for exploiting their biotechnological potential have so far been established only for a few model strains of cyanobacteria, while large untapped biosynthetic resources are hidden in slow-growing cyanobacterial genera that are difficult to access by genetic techniques. In recent years, several approaches have been developed to circumvent the bottlenecks in cyanobacterial natural product research. Here, we summarize current progress that has been made in unlocking or characterizing cryptic metabolic pathways using integrated omics techniques, orphan gene cluster activation, use of genetic approaches in original producers, heterologous expression and chemo-enzymatic techniques. We are mainly highlighting genomic mining concepts and strategies towards high-titer production of cyanobacterial natural products from the last 10 years and discuss the need for further research developments in this field.
Collapse
Affiliation(s)
- Martin Baunach
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany.
- University of Bonn, Institute of Pharmaceutical Biology, Nußallee 6, 53115 Bonn, Germany
| | - Arthur Guljamow
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany.
| | - María Miguel-Gordo
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany.
| | - Elke Dittmann
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany.
| |
Collapse
|
3
|
Dayang Najwa AB, Elexson N, Dalene L, Teng ST. Vibrio Species and Cyanobacteria: Understanding Their Association in Local Shrimp Farm Using Canonical Correspondence Analysis (CCA). MICROBIAL ECOLOGY 2024; 87:51. [PMID: 38488929 PMCID: PMC10943157 DOI: 10.1007/s00248-024-02356-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/29/2024] [Indexed: 03/17/2024]
Abstract
In aquatic environments, Vibrio and cyanobacteria establish varying relationships influenced by environmental factors. To investigate their association, this study spanned 5 months at a local shrimp farm, covering the shrimp larvae stocking cycle until harvesting. A total of 32 samples were collected from pond A (n = 6), pond B (n = 6), effluent (n = 10), and influent (n = 10). Vibrio species and cyanobacteria density were observed, and canonical correspondence analysis (CCA) assessed their correlation. CCA revealed a minor correlation (p = 0.847, 0.255, 0.288, and 0.304) between Vibrio and cyanobacteria in pond A, pond B, effluent, and influent water, respectively. Notably, Vibrio showed a stronger correlation with pH (6.14-7.64), while cyanobacteria correlated with pH, salinity (17.4-24 ppt), and temperature (30.8-31.5 °C), with salinity as the most influential factor. This suggests that factors beyond cyanobacteria influence Vibrio survival. Future research could explore species-specific relationships, regional dynamics, and multidimensional landscapes to better understand Vibrio-cyanobacteria connections. Managing water parameters may prove more efficient in controlling vibriosis in shrimp farms than targeting cyanobacterial populations.
Collapse
Affiliation(s)
- Awg Baki Dayang Najwa
- Faculty of Resource Science and Technology, University Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia
| | - Nillian Elexson
- Faculty of Resource Science and Technology, University Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia.
| | - Lesen Dalene
- Faculty of Resource Science and Technology, University Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia
| | - Sing Tung Teng
- Faculty of Resource Science and Technology, University Malaysia Sarawak, 94300, Kota Samarahan, Sarawak, Malaysia
| |
Collapse
|
4
|
Ortiz Tena F, Bickel V, Steinweg C, Posten C. Continuous microalgae cultivation for wastewater treatment - Development of a process strategy during day and night. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169082. [PMID: 38056654 DOI: 10.1016/j.scitotenv.2023.169082] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 12/01/2023] [Accepted: 12/01/2023] [Indexed: 12/08/2023]
Abstract
Conventional wastewater treatment (WWT) is not able to recycle nutrients from the wastewater (WW) directly. Microalgae integrate the valuable nutrients nitrogen and phosphorus within their biomass very efficiently, making them predestined for an application in WWT. Nevertheless, microalgae-based processes are driven by natural sunlight as energy source, making a continuous process mode during day and night difficult. The aim of this study was therefore to investigate metabolic activities of the continuously cultivated microalgae Chlorella vulgaris at light and dark periods (16 h,8 h) with focus on nutrient uptake during night from a synthetic WW. Varying the dilution rate D (D = 0.0-1.0 d-1 in 0.1 d-1-steps) causes different limitations for algae growth. Nutrient limitations at low D's cause maximum accumulation of intracellular storage components (sum of carbohydrates and lipids) of ~70 % of dry biomass, starch is converted to lipids at the absence of light. From middle to high D's, the growth rate is determined by light limitation, reducing the intracellular storage components to ~20 % of dry biomass. Complete nutrient uptake is measurable up to D = 0.5 d-1, marking the maximum operating point for wastewater purification. At that point, cells are characterised by high protein (up to 57%DBM) and pigment (up to 6.9%DBM) quotas. During the night, the build-up of proteins at the degradation of intracellular storage components is furthermore visible. Applying the concept of active biomass (cells without storage components), a constant cellular protein (~68%ABM) and nitrogen quota (11.94%ABM) was revealed. A nitrogen spiking experiment clearly showed nitrogen uptake and proliferation during the night period. Based on the experimental data, a window of operation for a continuous WWT process was designed, allowing the hypothesis that continuous WWT using microalgae during day and night operation is possible without the supplementation of artificial light. This revealed the system's capacity to treat WW throughout 24 h applying cell recycling and storage of carbohydrate-rich biomass. At the end of the night, protein-rich biomass is available for further valorisation.
Collapse
Affiliation(s)
- Franziska Ortiz Tena
- Karlsruhe Institute of Technology (KIT), Institute of Process Engineering in Life Sciences, Bioprocess Engineering, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany.
| | - Victoria Bickel
- Karlsruhe Institute of Technology (KIT), Institute of Process Engineering in Life Sciences, Bioprocess Engineering, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany
| | - Christian Steinweg
- Karlsruhe Institute of Technology (KIT), Institute of Process Engineering in Life Sciences, Bioprocess Engineering, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany
| | - Clemens Posten
- Karlsruhe Institute of Technology (KIT), Institute of Process Engineering in Life Sciences, Bioprocess Engineering, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany
| |
Collapse
|
5
|
Murik O, Geffen O, Shotland Y, Fernandez-Pozo N, Ullrich KK, Walther D, Rensing SA, Treves H. Genomic imprints of unparalleled growth. THE NEW PHYTOLOGIST 2024; 241:1144-1160. [PMID: 38072860 DOI: 10.1111/nph.19444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 10/31/2023] [Indexed: 12/23/2023]
Abstract
Chlorella ohadii was isolated from desert biological soil crusts, one of the harshest habitats on Earth, and is emerging as an exciting new green model for studying growth, photosynthesis and metabolism under a wide range of conditions. Here, we compared the genome of C. ohadii, the fastest growing alga on record, to that of other green algae, to reveal the genomic imprints empowering its unparalleled growth rate and resistance to various stressors, including extreme illumination. This included the genome of its close relative, but slower growing and photodamage sensitive, C. sorokiniana UTEX 1663. A larger number of ribosome-encoding genes, high intron abundance, increased codon bias and unique genes potentially involved in metabolic flexibility and resistance to photodamage are all consistent with the faster growth of C. ohadii. Some of these characteristics highlight general trends in Chlorophyta and Chlorella spp. evolution, and others open new broad avenues for mechanistic exploration of their relationship with growth. This work entails a unique case study for the genomic adaptations and costs of exceptionally fast growth and sheds light on the genomic signatures of fast growth in photosynthetic cells. It also provides an important resource for future studies leveraging the unique properties of C. ohadii for photosynthesis and stress response research alongside their utilization for synthetic biology and biotechnology aims.
Collapse
Affiliation(s)
- Omer Murik
- Department of Plant and Environmental Sciences, Hebrew University of Jerusalem, 91904, Jerusalem, Israel
- Medical Genetics Institute, Shaare Zedek Medical Center, 93722, Jerusalem, Israel
| | - Or Geffen
- School of Plant Sciences and Food Security, Tel-Aviv University, 39040, Tel-Aviv, Israel
| | - Yoram Shotland
- Chemical Engineering, Shamoon College of Engineering, 84100, Beer-Sheva, Israel
| | - Noe Fernandez-Pozo
- Plant Cell Biology, Department of Biology, University of Marburg, 35037, Marburg, Germany
| | - Kristian Karsten Ullrich
- Plant Cell Biology, Department of Biology, University of Marburg, 35037, Marburg, Germany
- Max-Planck Institute for Evolutionary Biology, 24306, Plön, Germany
| | - Dirk Walther
- Max-Planck Institute for Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Stefan Andreas Rensing
- Plant Cell Biology, Department of Biology, University of Marburg, 35037, Marburg, Germany
- Center for Biological Signaling Studies (BIOSS), University of Freiburg, 79098, Freiburg, Germany
| | - Haim Treves
- School of Plant Sciences and Food Security, Tel-Aviv University, 39040, Tel-Aviv, Israel
- Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663, Kaiserslautern, Germany
| |
Collapse
|
6
|
Balakrishnan R, Cremer J. Conditionally unutilized proteins and their profound effects on growth and adaptation across microbial species. Curr Opin Microbiol 2023; 75:102366. [PMID: 37625262 DOI: 10.1016/j.mib.2023.102366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/12/2023] [Accepted: 07/24/2023] [Indexed: 08/27/2023]
Abstract
Protein synthesis is an important determinant of microbial growth and response that demands a high amount of metabolic and biosynthetic resources. Despite these costs, microbial species from different taxa and habitats massively synthesize proteins that are not utilized in the conditions they currently experience. Based on resource allocation models, recent studies have begun to reconcile the costs and benefits of these conditionally unutilized proteins (CUPs) in the context of varying environmental conditions. Such massive synthesis of CUPs is crucial to consider in different areas of modern microbiology, from the systematic investigation of cell physiology, via the prediction of evolution in laboratory and natural environments, to the rational design of strains in biotechnology applications.
Collapse
Affiliation(s)
- Rohan Balakrishnan
- Department of Physics, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
| | - Jonas Cremer
- Department of Biology, Stanford University, 318 Campus Drive, Stanford, CA 93105, USA.
| |
Collapse
|
7
|
Foroutan F, Kyffin BA, Nikolaou A, Merino-Gutierrez J, Abrahams I, Kanwal N, Knowles JC, Smith AJ, Smales GJ, Carta D. Highly porous phosphate-based glasses for controlled delivery of antibacterial Cu ions prepared via sol-gel chemistry. RSC Adv 2023; 13:19662-19673. [PMID: 37396829 PMCID: PMC10308344 DOI: 10.1039/d3ra02958a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 06/07/2023] [Indexed: 07/04/2023] Open
Abstract
Mesoporous glasses are a promising class of bioresorbable biomaterials characterized by high surface area and extended porosity in the range of 2 to 50 nm. These peculiar properties make them ideal materials for the controlled release of therapeutic ions and molecules. Whilst mesoporous silicate-based glasses (MSG) have been widely investigated, much less work has been done on mesoporous phosphate-based glasses (MPG). In the present study, MPG in the P2O5-CaO-Na2O system, undoped and doped with 1, 3, and 5 mol% of Cu ions were synthesized via a combination of the sol-gel method and supramolecular templating. The non-ionic triblock copolymer Pluronic P123 was used as a templating agent. The porous structure was studied via a combination of Scanning Electron Microscopy (SEM), Small-Angle X-ray Scattering (SAXS), and N2 adsorption-desorption analysis at 77 K. The structure of the phosphate network was investigated via solid state 31P Magic Angle Spinning Nuclear Magnetic Resonance (31P MAS-NMR) and Fourier Transform Infrared (FTIR) spectroscopy. Degradation studies, performed in water via Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), showed that phosphates, Ca2+, Na+ and Cu ions are released in a controlled manner over a 7 days period. The controlled release of Cu, proportional to the copper loading, imbues antibacterial properties to MPG. A significant statistical reduction of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacterial viability was observed over a 3 days period. E. coli appeared to be more resistant than S. aureus to the antibacterial effect of copper. This study shows that copper doped MPG have great potential as bioresorbable materials for controlled delivery of antibacterial ions.
Collapse
Affiliation(s)
- Farzad Foroutan
- School of Chemistry and Chemical Engineering, University of Surrey Guildford UK
| | - Benjamin A Kyffin
- School of Chemistry and Chemical Engineering, University of Surrey Guildford UK
| | - Athanasios Nikolaou
- School of Chemistry and Chemical Engineering, University of Surrey Guildford UK
| | | | - Isaac Abrahams
- Department of Chemistry, Queen Mary University of London Mile End Road London E1 4NS UK
| | - Nasima Kanwal
- Department of Chemistry, Queen Mary University of London Mile End Road London E1 4NS UK
| | - Jonathan C Knowles
- Division of Biomaterials and Tissue Engineering, University College London London UK
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University Cheonan Republic of Korea
- UCL Eastman-Korea Dental Medicine Innovation Centre, Dankook University Cheonan Republic of Korea
| | - Andrew J Smith
- Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus Didcot, Oxfordshire OX11 0DE UK
| | - Glen J Smales
- Bundesanstalt für Materialforschung und -prüfung (BAM) Berlin Germany
| | - Daniela Carta
- School of Chemistry and Chemical Engineering, University of Surrey Guildford UK
| |
Collapse
|
8
|
Burnap RL. Cyanobacterial Bioenergetics in Relation to Cellular Growth and Productivity. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2023; 183:25-64. [PMID: 36764956 DOI: 10.1007/10_2022_215] [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: 02/12/2023]
Abstract
Cyanobacteria, the evolutionary originators of oxygenic photosynthesis, have the capability to convert CO2, water, and minerals into biomass using solar energy. This process is driven by intricate bioenergetic mechanisms that consist of interconnected photosynthetic and respiratory electron transport chains coupled. Over the last few decades, advances in physiochemical analysis, molecular genetics, and structural analysis have enabled us to gain a more comprehensive understanding of cyanobacterial bioenergetics. This includes the molecular understanding of the primary energy conversion mechanisms as well as photoprotective and other dissipative mechanisms that prevent photodamage when the rates of photosynthetic output, primarily in the form of ATP and NADPH, exceed the rates that cellular assimilatory processes consume these photosynthetic outputs. Despite this progress, there is still much to learn about the systems integration and the regulatory circuits that control expression levels for optimal cellular abundance and activity of the photosynthetic complexes and the cellular components that convert their products into biomass. With an improved understanding of these regulatory principles and mechanisms, it should be possible to optimally modify cyanobacteria for enhanced biotechnological purposes.
Collapse
Affiliation(s)
- Robert L Burnap
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA.
| |
Collapse
|
9
|
Mechanisms of Stress Tolerance in Cyanobacteria under Extreme Conditions. STRESSES 2022. [DOI: 10.3390/stresses2040036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cyanobacteria are oxygen-evolving photoautotrophs with worldwide distribution in every possible habitat, and they account for half of the global primary productivity. Because of their ability to thrive in a hostile environment, cyanobacteria are categorized as “extremophiles”. They have evolved a fascinating repository of distinct secondary metabolites and biomolecules to promote their development and survival in various habitats, including severe conditions. However, developing new proteins/enzymes and metabolites is mostly directed by an appropriate gene regulation system that results in stress adaptations. However, only few proteins have been characterized to date that have the potential to improve resistance against abiotic stresses. As a result, studying environmental stress responses to post-genomic analysis, such as proteome changes using latest structural proteomics and synthetic biology techniques, is critical. In this regard, scientists working on these topics will benefit greatly from the stress of proteomics research. Progress in these disciplines will aid in understanding cyanobacteria’s physiology, biochemical, and metabolic systems. This review summarizes the most recent key findings of cyanobacterial proteome study under various abiotic stresses and the application of secondary metabolites formed during different abiotic conditions.
Collapse
|
10
|
Riaz S, Jiang Y, Xiao M, You D, Klepacz-Smółka A, Rasul F, Daroch M. Generation of miniploid cells and improved natural transformation procedure for a model cyanobacterium Synechococcus elongatus PCC 7942. Front Microbiol 2022; 13:959043. [PMID: 35958137 PMCID: PMC9360974 DOI: 10.3389/fmicb.2022.959043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 07/01/2022] [Indexed: 11/13/2022] Open
Abstract
The biotechnologically important and naturally transformable cyanobacterium, Synechococcus elongatus PCC 7942, possesses multiple genome copies irrespective of its growth rate or condition. Hence, segregating mutations across all genome copies typically takes several weeks. In this study, Synechococcus 7942 cultivation on a solid growth medium was optimised using different concentrations of agar, the addition of antioxidants, and overexpression of the catalase gene to facilitate the rapid acquisition of colonies and fully segregated lines. Synechococcus 7942 was grown at different temperatures and nutritional conditions. The miniploid cells were identified using flow cytometry and fluorimetry. The natural transformation was carried out using miniploid cells and validated with PCR and high performance liquid chromatography (HPLC). We identified that 0.35% agar concentration and 200 IU of catalase could improve the growth of Synechococcus 7942 on a solid growth medium. Furthermore, overexpression of a catalase gene enhanced the growth rate and supported diluted culture to grow on a solid medium. Our results reveal that high temperature and phosphate-depleted cells contain the lowest genome copies (2.4 ± 0.3 and 1.9 ± 0.2) and showed the potential to rapidly produce fully segregated mutants. In addition, higher antibiotic concentrations improve the selection of homozygous transformants while maintaining similar genome copies at a constant temperature. Based on our observation, we have an improved cultivation and natural transformation protocol for Synechococcus 7942 by optimising solid media culturing, generating low-ploidy cells that ultimately reduced the time required for the complete segregation of engineered lines.
Collapse
Affiliation(s)
- Sadaf Riaz
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, United States
| | - Ying Jiang
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Meng Xiao
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Dawei You
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Anna Klepacz-Smółka
- Department of Bioprocess Engineering, Faculty of Process and Environmental Engineering, University of Technology, Łódź, Poland
| | - Faiz Rasul
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Maurycy Daroch
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
| |
Collapse
|
11
|
Chen Y, Li EM, Xu LY. Guide to Metabolomics Analysis: A Bioinformatics Workflow. Metabolites 2022; 12:357. [PMID: 35448542 PMCID: PMC9032224 DOI: 10.3390/metabo12040357] [Citation(s) in RCA: 65] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/12/2022] [Accepted: 04/14/2022] [Indexed: 02/05/2023] Open
Abstract
Metabolomics is an emerging field that quantifies numerous metabolites systematically. The key purpose of metabolomics is to identify the metabolites corresponding to each biological phenotype, and then provide an analysis of the mechanisms involved. Although metabolomics is important to understand the involved biological phenomena, the approach's ability to obtain an exhaustive description of the processes is limited. Thus, an analysis-integrated metabolomics, transcriptomics, proteomics, and other omics approach is recommended. Such integration of different omics data requires specialized statistical and bioinformatics software. This review focuses on the steps involved in metabolomics research and summarizes several main tools for metabolomics analyses. We also outline the most abnormal metabolic pathways in several cancers and diseases, and discuss the importance of multi-omics integration algorithms. Overall, our goal is to summarize the current metabolomics analysis workflow and its main analysis software to provide useful insights for researchers to establish a preferable pipeline of metabolomics or multi-omics analysis.
Collapse
Affiliation(s)
- Yang Chen
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou 515041, China
- Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou 515041, China
| | - En-Min Li
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou 515041, China
- Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou 515041, China
| | - Li-Yan Xu
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou 515041,
| |
Collapse
|
12
|
Theodosiou E, Tüllinghoff A, Toepel J, Bühler B. Exploitation of Hetero- and Phototrophic Metabolic Modules for Redox-Intensive Whole-Cell Biocatalysis. Front Bioeng Biotechnol 2022; 10:855715. [PMID: 35497353 PMCID: PMC9043136 DOI: 10.3389/fbioe.2022.855715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 03/09/2022] [Indexed: 11/13/2022] Open
Abstract
The successful realization of a sustainable manufacturing bioprocess and the maximization of its production potential and capacity are the main concerns of a bioprocess engineer. A main step towards this endeavor is the development of an efficient biocatalyst. Isolated enzyme(s), microbial cells, or (immobilized) formulations thereof can serve as biocatalysts. Living cells feature, beside active enzymes, metabolic modules that can be exploited to support energy-dependent and multi-step enzyme-catalyzed reactions. Metabolism can sustainably supply necessary cofactors or cosubstrates at the expense of readily available and cheap resources, rendering external addition of costly cosubstrates unnecessary. However, for the development of an efficient whole-cell biocatalyst, in depth comprehension of metabolic modules and their interconnection with cell growth, maintenance, and product formation is indispensable. In order to maximize the flux through biosynthetic reactions and pathways to an industrially relevant product and respective key performance indices (i.e., titer, yield, and productivity), existing metabolic modules can be redesigned and/or novel artificial ones established. This review focuses on whole-cell bioconversions that are coupled to heterotrophic or phototrophic metabolism and discusses metabolic engineering efforts aiming at 1) increasing regeneration and supply of redox equivalents, such as NAD(P/H), 2) blocking competing fluxes, and 3) increasing the availability of metabolites serving as (co)substrates of desired biosynthetic routes.
Collapse
Affiliation(s)
- Eleni Theodosiou
- Institute of Applied Biosciences, Centre for Research and Technology Hellas, Thessaloniki, Greece
| | - Adrian Tüllinghoff
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH—UFZ, Leipzig, Germany
| | - Jörg Toepel
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH—UFZ, Leipzig, Germany
| | - Bruno Bühler
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH—UFZ, Leipzig, Germany
| |
Collapse
|
13
|
Battaglino B, Du W, Pagliano C, Jongbloets JA, Re A, Saracco G, Branco dos Santos F. Channeling Anabolic Side Products toward the Production of Nonessential Metabolites: Stable Malate Production in Synechocystis sp. PCC6803. ACS Synth Biol 2021; 10:3518-3526. [PMID: 34808039 PMCID: PMC8689693 DOI: 10.1021/acssynbio.1c00440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Powered by (sun)light to oxidize water, cyanobacteria can directly convert atmospheric CO2 into valuable carbon-based compounds and meanwhile release O2 to the atmosphere. As such, cyanobacteria are promising candidates to be developed as microbial cell factories for the production of chemicals. Nevertheless, similar to other microbial cell factories, engineered cyanobacteria may suffer from production instability. The alignment of product formation with microbial fitness is a valid strategy to tackle this issue. We have described previously the "FRUITS" algorithm for the identification of metabolites suitable to be coupled to growth (i.e., side products in anabolic reactions) in the model cyanobacterium Synechocystis. sp PCC6803. However, the list of candidate metabolites identified using this algorithm can be somewhat limiting, due to the inherent structure of metabolic networks. Here, we aim at broadening the spectrum of candidate compounds beyond the ones predicted by FRUITS, through the conversion of a growth-coupled metabolite to downstream metabolites via thermodynamically favored conversions. We showcase the feasibility of this approach for malate production using fumarate as the growth-coupled substrate in Synechocystis mutants. A final titer of ∼1.2 mM was achieved for malate during photoautotrophic batch cultivations. Under prolonged continuous cultivation, the most efficient malate-producing strain can maintain its productivity for at least 45 generations, sharply contrasting with other producing Synechocystis strains engineered with classical approaches. Our study also opens a new possibility for extending the stable production concept to derivatives of growth-coupled metabolites, increasing the list of suitable target compounds.
Collapse
Affiliation(s)
- Beatrice Battaglino
- Applied Science and Technology Department, BioSolar Lab, Politecnico di Torino, Environment
Park, Via Livorno 60, 10144 Torino, Italy
- Centre for Sustainable Future Technologies, Istituto Italiano di Tecnologia, Environment
Park, Via Livorno 60, 10144 Torino, Italy
| | - Wei Du
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - Cristina Pagliano
- Applied Science and Technology Department, BioSolar Lab, Politecnico di Torino, Environment
Park, Via Livorno 60, 10144 Torino, Italy
| | - Joeri A. Jongbloets
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
| | - Angela Re
- Centre for Sustainable Future Technologies, Istituto Italiano di Tecnologia, Environment
Park, Via Livorno 60, 10144 Torino, Italy
| | - Guido Saracco
- Applied Science and Technology Department, BioSolar Lab, Politecnico di Torino, Environment
Park, Via Livorno 60, 10144 Torino, Italy
| | - Filipe Branco dos Santos
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands
| |
Collapse
|
14
|
In vitro activity of reconstituted rubisco enzyme from Gloeobacter violaceus. J Biosci 2021. [DOI: 10.1007/s12038-021-00188-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
15
|
Amadu AA, Qiu S, Ge S, Addico GND, Ameka GK, Yu Z, Xia W, Abbew AW, Shao D, Champagne P, Wang S. A review of biopolymer (Poly-β-hydroxybutyrate) synthesis in microbes cultivated on wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 756:143729. [PMID: 33310224 DOI: 10.1016/j.scitotenv.2020.143729] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 06/12/2023]
Abstract
The large quantities of non-degradable single use plastics, production and disposal, in addition to increasing amounts of municipal and industrial wastewaters are among the major global issues known today. Biodegradable plastics from biopolymers such as Poly-β-hydroxybutyrates (PHB) produced by microorganisms are potential substitutes for non-degradable petroleum-based plastics. This paper reviews the current status of wastewater-cultivated microbes utilized in PHB production, including the various types of wastewaters suitable for either pure or mixed culture PHB production. PHB-producing strains that have the potential for commercialization are also highlighted with proposed selection criteria for choosing the appropriate PHB microbe for optimization of processes. The biosynthetic pathways involved in producing microbial PHB are also discussed to highlight the advancements in genetic engineering techniques. Additionally, the paper outlines the factors influencing PHB production while exploring other metabolic pathways and metabolites simultaneously produced along with PHB in a bio-refinery context. Furthermore, the paper explores the effects of extraction methods on PHB yield and quality to ultimately facilitate the commercial production of biodegradable plastics. This review uniquely discusses the developments in research on microbial biopolymers, specifically PHB and also gives an overview of current commercial PHB companies making strides in cutting down plastic pollution and greenhouse gases.
Collapse
Affiliation(s)
- Ayesha Algade Amadu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Shuang Qiu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Shijian Ge
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China.
| | - Gloria Naa Dzama Addico
- Council for Scientific and Industrial Research (CSIR) - Water Research Institute (WRI), P.O. Box AH 38, Achimota Greater Accra, Ghana
| | - Gabriel Komla Ameka
- Department of Botany, University of Ghana, P.O. Box LG55, Legon, Accra, Ghana
| | - Ziwei Yu
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Wenhao Xia
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Abdul-Wahab Abbew
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Dadong Shao
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, PR China
| | - Pascale Champagne
- Department of Civil Engineering, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Sufeng Wang
- School of Economics and Management, Anhui Jianzhu University, Hefei, Anhui 230601, PR China
| |
Collapse
|
16
|
Liu D, Liberton M, Hendry JI, Aminian-Dehkordi J, Maranas CD, Pakrasi HB. Engineering biology approaches for food and nutrient production by cyanobacteria. Curr Opin Biotechnol 2020; 67:1-6. [PMID: 33129046 DOI: 10.1016/j.copbio.2020.09.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/13/2020] [Accepted: 09/21/2020] [Indexed: 01/10/2023]
Abstract
As photoautotrophic organisms, cyanobacteria capture and store solar energy in the form of biomass. Cyanobacterial biomass has been an important component of diet and nutrition in several regions for centuries. Synthetic biology strategies are currently being applied to increase the yield and productivity of cyanobacterial biomass by optimizing solar energy utilization and CO2 fixation rates for carbon storage. Likewise, engineering cyanobacteria as cellular factories to synthesize carbohydrates, amino acids, proteins, lipids and fatty acids is providing an attractive way to sustainably produce food and nutrients for human consumption. In this review, we have summarized recent progress in both aspects and prospective trends under development.
Collapse
Affiliation(s)
- Deng Liu
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - Michelle Liberton
- Department of Biology, Washington University, St. Louis, MO 63130, USA
| | - John I Hendry
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Javad Aminian-Dehkordi
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Costas D Maranas
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Himadri B Pakrasi
- Department of Biology, Washington University, St. Louis, MO 63130, USA.
| |
Collapse
|
17
|
Tee HS, Waite D, Payne L, Middleditch M, Wood S, Handley KM. Tools for successful proliferation: diverse strategies of nutrient acquisition by a benthic cyanobacterium. THE ISME JOURNAL 2020; 14:2164-2178. [PMID: 32424245 PMCID: PMC7367855 DOI: 10.1038/s41396-020-0676-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 04/23/2020] [Accepted: 05/01/2020] [Indexed: 12/28/2022]
Abstract
Freshwater cyanobacterial blooms have increased worldwide, channeling organic carbon into these systems, and threatening animal health through the production of cyanotoxins. Both toxic and nontoxic Microcoleus proliferations usually occur when there are moderate concentrations of dissolved inorganic nitrogen, but when phosphorus is scarce. In order to understand how Microcoleus establishes thick biofilms (or mats) on riverbeds under phosphorus-limiting conditions, we collected Microcoleus-dominated biofilms over a 19-day proliferation event for proteogenomics. A single pair of nitrogen-dependent Microcoleus species were consistently present in relatively high abundance, although each followed a unique metabolic trajectory. Neither possessed anatoxin gene clusters, and only very low concentrations of anatoxins (~2 µg kg-1) were detected, likely originating from rarer Microcoleus species also present. Proteome allocations were dominated by photosynthesizing cyanobacteria and diatoms, and data indicate biomass was actively recycled by Bacteroidetes and Myxococcales. Microcoleus likely acquired nutrients throughout the proliferation event by uptake of nitrate, urea, and inorganic and organic phosphorus. Both species also harbored genes that could be used for inorganic phosphate solubilization with pyrroloquinoline quinone cofactors produced by cohabiting Proteobacteria. Results indicate that Microcoleus are equipped with diverse mechanisms for nitrogen and phosphorus acquisition, enabling them to proliferate and out-compete others in low-phosphorus waters.
Collapse
Affiliation(s)
- H S Tee
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - D Waite
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - L Payne
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - M Middleditch
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - S Wood
- Cawthron Institute, Nelson, New Zealand
| | - K M Handley
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.
| |
Collapse
|
18
|
Inomura K, Omta AW, Talmy D, Bragg J, Deutsch C, Follows MJ. A Mechanistic Model of Macromolecular Allocation, Elemental Stoichiometry, and Growth Rate in Phytoplankton. Front Microbiol 2020; 11:86. [PMID: 32256456 PMCID: PMC7093025 DOI: 10.3389/fmicb.2020.00086] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 01/15/2020] [Indexed: 01/09/2023] Open
Abstract
We present a model of the growth rate and elemental stoichiometry of phytoplankton as a function of resource allocation between and within broad macromolecular pools under a variety of resource supply conditions. The model is based on four, empirically-supported, cornerstone assumptions: that there is a saturating relationship between light and photosynthesis, a linear relationship between RNA/protein and growth rate, a linear relationship between biosynthetic proteins and growth rate, and a constant macromolecular composition of the light-harvesting machinery. We combine these assumptions with statements of conservation of carbon, nitrogen, phosphorus, and energy. The model can be solved algebraically for steady state conditions and constrained with data on elemental stoichiometry from published laboratory chemostat studies. It interprets the relationships between macromolecular and elemental stoichiometry and also provides quantitative predictions of the maximum growth rate at given light intensity and nutrient supply rates. The model is compatible with data sets from several laboratory studies characterizing both prokaryotic and eukaryotic phytoplankton from marine and freshwater environments. It is conceptually simple, yet mechanistic and quantitative. Here, the model is constrained only by elemental stoichiometry, but makes predictions about allocation to measurable macromolecular pools, which could be tested in the laboratory.
Collapse
Affiliation(s)
- Keisuke Inomura
- School of Oceanography, University of Washington, Seattle, WA, United States
| | - Anne Willem Omta
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - David Talmy
- Department of Microbiology, University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Jason Bragg
- National Herbarium of New South Wales, The Royal Botanic Gardens and Domain Trust, Sydney, NSW, Australia
| | - Curtis Deutsch
- School of Oceanography, University of Washington, Seattle, WA, United States
| | - Michael J. Follows
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| |
Collapse
|
19
|
Inomura K, Follett CL, Masuda T, Eichner M, Prášil O, Deutsch C. Carbon Transfer from the Host Diatom Enables Fast Growth and High Rate of N 2 Fixation by Symbiotic Heterocystous Cyanobacteria. PLANTS (BASEL, SWITZERLAND) 2020; 9:E192. [PMID: 32033207 PMCID: PMC7076409 DOI: 10.3390/plants9020192] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/20/2020] [Accepted: 01/30/2020] [Indexed: 12/25/2022]
Abstract
Diatom-diazotroph associations (DDAs) are symbioses where trichome-forming cyanobacteria support the host diatom with fixed nitrogen through dinitrogen (N2) fixation. It is inferred that the growth of the trichomes is also supported by the host, but the support mechanism has not been fully quantified. Here, we develop a coarse-grained, cellular model of the symbiosis between Hemiaulus and Richelia (one of the major DDAs), which shows that carbon (C) transfer from the diatom enables a faster growth and N2 fixation rate by the trichomes. The model predicts that the rate of N2 fixation is 5.5 times that of the hypothetical case without nitrogen (N) transfer to the host diatom. The model estimates that 25% of fixed C from the host diatom is transferred to the symbiotic trichomes to support the high rate of N2 fixation. In turn, 82% of N fixed by the trichomes ends up in the host. Modeled C fixation from the vegetative cells in the trichomes supports only one-third of their total C needs. Even if we ignore the C cost for N2 fixation and for N transfer to the host, the total C cost of the trichomes is higher than the C supply by their own photosynthesis. Having more trichomes in a single host diatom decreases the demand for N2 fixation per trichome and thus decreases their cost of C. However, even with five trichomes, which is about the highest observed for Hemiaulus and Richelia symbiosis, the model still predicts a significant C transfer from the diatom host. These results help quantitatively explain the observed high rates of growth and N2 fixation in symbiotic trichomes relative to other aquatic diazotrophs.
Collapse
Affiliation(s)
- Keisuke Inomura
- School of Oceanography, University of Washington, 1492 NE Boat St., Seattle, WA 98105, USA;
| | - Christopher L. Follett
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA;
- School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK
| | - Takako Masuda
- Institute of Microbiology, The Czech Academy of Sciences, 379 81b Třeboň, Czech Republic; (T.M.); (M.E.); (O.P.)
| | - Meri Eichner
- Institute of Microbiology, The Czech Academy of Sciences, 379 81b Třeboň, Czech Republic; (T.M.); (M.E.); (O.P.)
| | - Ondřej Prášil
- Institute of Microbiology, The Czech Academy of Sciences, 379 81b Třeboň, Czech Republic; (T.M.); (M.E.); (O.P.)
| | - Curtis Deutsch
- School of Oceanography, University of Washington, 1492 NE Boat St., Seattle, WA 98105, USA;
| |
Collapse
|
20
|
Malek Shahkouhi A, Motamedian E. Reconstruction of a regulated two-cell metabolic model to study biohydrogen production in a diazotrophic cyanobacterium Anabaena variabilis ATCC 29413. PLoS One 2020; 15:e0227977. [PMID: 31978122 PMCID: PMC6980584 DOI: 10.1371/journal.pone.0227977] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 01/03/2020] [Indexed: 12/21/2022] Open
Abstract
Anabaena variabilis is a diazotrophic filamentous cyanobacterium that differentiates to heterocysts and produces hydrogen as a byproduct. Study on metabolic interactions of the two differentiated cells provides a better understanding of its metabolism especially for improving hydrogen production. To this end, a genome-scale metabolic model for Anabaena variabilis ATCC 29413, iAM957, was reconstructed and evaluated in this research. Then, the model and transcriptomic data of the vegetative and heterocyst cells were applied to construct a regulated two-cell metabolic model. The regulated model improved prediction for biomass in high radiation levels. The regulated model predicts that heterocysts provide an oxygen-free environment and then, this model was used to find strategies for improving hydrogen production in heterocysts. The predictions indicate that the removal of uptake hydrogenase improves hydrogen production which is consistent with previous empirical research. Furthermore, the regulated model proposed activation of some reactions to provide redox cofactors which are required for improving hydrogen production up to 60% by bidirectional hydrogenase.
Collapse
Affiliation(s)
- Ali Malek Shahkouhi
- Department of Biotechnology, Faculty of Chemical Engineering, Tarbiat Modares University, Tehran, Iran
| | - Ehsan Motamedian
- Department of Biotechnology, Faculty of Chemical Engineering, Tarbiat Modares University, Tehran, Iran
| |
Collapse
|
21
|
Wu C, Jiang H, Kalra I, Wang X, Cano M, Maness P, Yu J, Xiong W. A generalized computational framework to streamline thermodynamics and kinetics analysis of metabolic pathways. Metab Eng 2020; 57:140-150. [DOI: 10.1016/j.ymben.2019.08.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 07/18/2019] [Accepted: 08/07/2019] [Indexed: 12/25/2022]
|
22
|
Sharma S, Steuer R. Modelling microbial communities using biochemical resource allocation analysis. J R Soc Interface 2019; 16:20190474. [PMID: 31690234 PMCID: PMC6893496 DOI: 10.1098/rsif.2019.0474] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 10/15/2019] [Indexed: 01/08/2023] Open
Abstract
To understand the functioning and dynamics of microbial communities is a fundamental challenge in current biology. To tackle this challenge, the construction of computational models of interacting microbes is an indispensable tool. There is, however, a large chasm between ecologically motivated descriptions of microbial growth used in many current ecosystems simulations, and detailed metabolic pathway and genome-based descriptions developed in the context of systems and synthetic biology. Here, we seek to demonstrate how resource allocation models of microbial growth offer the potential to advance ecosystem simulations and their parametrization. In particular, recent work on quantitative resource allocation allow us to formulate mechanistic models of microbial growth that are physiologically meaningful while remaining computationally tractable. These models go beyond Michaelis-Menten and Monod-type growth models, and are capable of accounting for emergent properties that underlie the remarkable plasticity of microbial growth. We outline the utility and advantages of using biochemical resource allocation models by considering a coarse-grained model of cyanobacterial growth and demonstrate how the model allows us to address specific questions of relevance for the simulation of marine microbial ecosystems, including the physiological acclimation of protein expression to different environments, the description of co-limitation by several nutrients and the differential use of alternative nutrient sources, as well as the description of metabolic diversity based on our increasing knowledge about quantitative cell physiology.
Collapse
Affiliation(s)
| | - Ralf Steuer
- Humboldt-Universität zu Berlin, Institut für Biologie, FachInstitut für Theoretische Biologie (ITB), Invalidenstr. 110, 10115 Berlin, Germany
| |
Collapse
|
23
|
Active nitrogen fixation by Crocosphaera expands their niche despite the presence of ammonium - A case study. Sci Rep 2019; 9:15064. [PMID: 31636357 PMCID: PMC6803696 DOI: 10.1038/s41598-019-51378-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 09/30/2019] [Indexed: 11/09/2022] Open
Abstract
Unicellular nitrogen fixer Crocosphaera contributes substantially to nitrogen fixation in oligotrophic subtropical gyres. They fix nitrogen even when significant amounts of ammonium are available. This has been puzzling since fixing nitrogen is energetically inefficient compared with using available ammonium. Here we show that by fixing nitrogen, Crocosphaera can increase their population and expand their niche despite the presence of ammonium. We have developed a simple but mechanistic model of Crocosphaera based on their growth in steady state culture. The model shows that the growth of Crocosphaera can become nitrogen limited despite their capability to fix nitrogen. When they fix nitrogen, the population increases by up to 78% relative to the case without nitrogen fixation. When we simulate a simple ecological situation where Crocosphaera exists with non-nitrogen-fixing phytoplankton, the relative abundance of Crocosphaera increases with nitrogen fixation, while the population of non-nitrogen-fixing phytoplankton decreases since a larger fraction of fixed nitrogen is consumed by Crocosphaera. Our study quantitatively supports the benefit of nitrogen fixation despite the high electron/energy costs, even when an energetically efficient alternative is available. It demonstrates a competitive aspect of Crocosphaera, permitting them to be regionally significant nitrogen fixers.
Collapse
|
24
|
Faizi M, Steuer R. Optimal proteome allocation strategies for phototrophic growth in a light-limited chemostat. Microb Cell Fact 2019; 18:165. [PMID: 31601201 PMCID: PMC6785936 DOI: 10.1186/s12934-019-1209-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/06/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Cyanobacteria and other phototrophic microorganisms allow to couple the light-driven assimilation of atmospheric [Formula: see text] directly to the synthesis of carbon-based products, and are therefore attractive platforms for microbial cell factories. While most current engineering efforts are performed using small-scale laboratory cultivation, the economic viability of phototrophic cultivation also crucially depends on photobioreactor design and culture parameters, such as the maximal areal and volumetric productivities. Based on recent insights into the cyanobacterial cell physiology and the resulting computational models of cyanobacterial growth, the aim of this study is to investigate the limits of cyanobacterial productivity in continuous culture with light as the limiting nutrient. RESULTS We integrate a coarse-grained model of cyanobacterial growth into a light-limited chemostat and its heterogeneous light gradient induced by self-shading of cells. We show that phototrophic growth in the light-limited chemostat can be described using the concept of an average light intensity. Different from previous models based on phenomenological growth equations, our model provides a mechanistic link between intracellular protein allocation, population growth and the resulting reactor productivity. Our computational framework thereby provides a novel approach to investigate and predict the maximal productivity of phototrophic cultivation, and identifies optimal proteome allocation strategies for developing maximally productive strains. CONCLUSIONS Our results have implications for efficient phototrophic cultivation and the design of maximally productive phototrophic cell factories. The model predicts that the use of dense cultures in well-mixed photobioreactors with short light-paths acts as an effective light dilution mechanism and alleviates the detrimental effects of photoinhibition even under very high light intensities. We recover the well-known trade-offs between a reduced light-harvesting apparatus and increased population density. Our results are discussed in the context of recent experimental efforts to increase the yield of phototrophic cultivation.
Collapse
Affiliation(s)
- Marjan Faizi
- Institut für Biologie, Fachinstitut für Theoretische Biologie, Humboldt-Universität zu Berlin, Invalidenstr. 110, 10115, Berlin, Germany
| | - Ralf Steuer
- Institut für Biologie, Fachinstitut für Theoretische Biologie, Humboldt-Universität zu Berlin, Invalidenstr. 110, 10115, Berlin, Germany.
| |
Collapse
|
25
|
Alfonso-Garcia A, Li C, Bec J, Yankelevich D, Marcu L, Sherlock B. Fiber-based platform for synchronous imaging of endogenous and exogenous fluorescence of biological tissue. OPTICS LETTERS 2019; 44:3350-3353. [PMID: 31259958 PMCID: PMC7539616 DOI: 10.1364/ol.44.003350] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 06/01/2019] [Indexed: 05/29/2023]
Abstract
Endogenous and exogenous fluorescence emission from biological samples encodes complementary information. Here we report, to the best of our knowledge, the first results from an optical imaging platform with interleaved excitation and detection of exogenous and endogenous fluorescence from tissue samples using a single flexible multimode fiber that delivers the excitation beam and collects the emitted light. A custom-built reflective optical chopper wheel with synchronized rotation temporally multiplexes an autofluorescence lifetime imaging apparatus with an intensity-based fluorescence module tailored to imaging green fluorescent protein. We demonstrate the functionality of such platform imaging dyes of varying fluorescence signatures and resolving cellularized areas on bio-engineered tissue constructs.
Collapse
Affiliation(s)
- Alba Alfonso-Garcia
- Department of Biomedical Engineering, University of California, Davis, 451 E. Health Sciences Dr., Davis, California 95616, USA
| | - Cai Li
- Department of Biomedical Engineering, University of California, Davis, 451 E. Health Sciences Dr., Davis, California 95616, USA
| | - Julien Bec
- Department of Biomedical Engineering, University of California, Davis, 451 E. Health Sciences Dr., Davis, California 95616, USA
| | - Diego Yankelevich
- Department of Biomedical Engineering, University of California, Davis, 451 E. Health Sciences Dr., Davis, California 95616, USA
- Department of Electrical and Computer Engineering, University of California, Davis, One Shields Avenue, Kemper Hall, Davis, California 95616, USA
| | - Laura Marcu
- Department of Biomedical Engineering, University of California, Davis, 451 E. Health Sciences Dr., Davis, California 95616, USA
| | - Ben Sherlock
- Department of Biomedical Engineering, University of California, Davis, 451 E. Health Sciences Dr., Davis, California 95616, USA
| |
Collapse
|
26
|
Babele PK, Kumar J, Chaturvedi V. Proteomic De-Regulation in Cyanobacteria in Response to Abiotic Stresses. Front Microbiol 2019; 10:1315. [PMID: 31263458 PMCID: PMC6584798 DOI: 10.3389/fmicb.2019.01315] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 05/27/2019] [Indexed: 11/13/2022] Open
Abstract
Cyanobacteria are oxygenic photoautotrophs, exhibiting a cosmopolitan distribution in almost all possible environments and are significantly responsible for half of the global net primary productivity. They are well adapted to the diverse environments including harsh conditions by evolving a range of fascinating repertoires of unique biomolecules and secondary metabolites to support their growth and survival. These phototrophs are proved as excellent models for unraveling the mysteries of basic biochemical and physiological processes taking place in higher plants. Several known species of cyanobacteria have tremendous biotechnological applications in diverse fields such as biofuels, biopolymers, secondary metabolites and much more. Due to their potential biotechnological and commercial applications in various fields, there is an imperative need to engineer robust cyanobacteria in such a way that they can tolerate and acclimatize to ever-changing environmental conditions. Adaptations to stress are mainly governed by a precise gene regulation pathways resulting in the expression of novel protein/enzymes and metabolites. Despite the demand, till date few proteins/enzymes have been identified which play a potential role in improving tolerance against abiotic stresses. Therefore, it is utmost important to study environmental stress responses related to post-genomic investigations, including proteomic changes employing advanced proteomics, synthetic and structural biology workflows. In this respect, the study of stress proteomics offers exclusive advantages to scientists working on these aspects. Advancements on these fields could be helpful in dissecting, characterization and manipulation of physiological and metabolic systems of cyanobacteria to understand the stress induced proteomic responses. Till date, it remains ambiguous how cyanobacteria perceive changes in the ambient environment that lead to the stress-induced proteins thus metabolic deregulation. This review briefly describes the current major findings in the fields of proteome research on the cyanobacteria under various abiotic stresses. These findings may improve and advance the information on the role of different class of proteins associated with the mechanism(s) of stress mitigation in cyanobacteria under harsh environmental conditions.
Collapse
Affiliation(s)
- Piyoosh Kumar Babele
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, India
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Jay Kumar
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Venkatesh Chaturvedi
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
| |
Collapse
|
27
|
Zavřel T, Faizi M, Loureiro C, Poschmann G, Stühler K, Sinetova M, Zorina A, Steuer R, Červený J. Quantitative insights into the cyanobacterial cell economy. eLife 2019; 8:42508. [PMID: 30714903 PMCID: PMC6391073 DOI: 10.7554/elife.42508] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 02/01/2019] [Indexed: 01/27/2023] Open
Abstract
Phototrophic microorganisms are promising resources for green biotechnology. Compared to heterotrophic microorganisms, however, the cellular economy of phototrophic growth is still insufficiently understood. We provide a quantitative analysis of light-limited, light-saturated, and light-inhibited growth of the cyanobacterium Synechocystis sp. PCC 6803 using a reproducible cultivation setup. We report key physiological parameters, including growth rate, cell size, and photosynthetic activity over a wide range of light intensities. Intracellular proteins were quantified to monitor proteome allocation as a function of growth rate. Among other physiological acclimations, we identify an upregulation of the translational machinery and downregulation of light harvesting components with increasing light intensity and growth rate. The resulting growth laws are discussed in the context of a coarse-grained model of phototrophic growth and available data obtained by a comprehensive literature search. Our insights into quantitative aspects of cyanobacterial acclimations to different growth rates have implications to understand and optimize photosynthetic productivity.
Collapse
Affiliation(s)
- Tomáš Zavřel
- Laboratory of Adaptive BiotechnologiesGlobal Change Research Institute CASBrnoCzech Republic
| | - Marjan Faizi
- Institut für Biologie, Fachinstitut für Theoretische BiologieHumboldt-Universität zu BerlinBerlinGermany
| | - Cristina Loureiro
- Department of Applied PhysicsPolytechnic University of ValenciaValenciaSpain
| | - Gereon Poschmann
- Molecular Proteomics Laboratory, BMFZHeinrich-Heine-Universität DüsseldorfDüsseldorfGermany
| | - Kai Stühler
- Molecular Proteomics Laboratory, BMFZHeinrich-Heine-Universität DüsseldorfDüsseldorfGermany
| | - Maria Sinetova
- Timiryazev Institute of Plant PhysiologyRussian Academy of SciencesMoscowRussian Federation
| | - Anna Zorina
- Timiryazev Institute of Plant PhysiologyRussian Academy of SciencesMoscowRussian Federation
| | - Ralf Steuer
- Institut für Biologie, Fachinstitut für Theoretische BiologieHumboldt-Universität zu BerlinBerlinGermany
| | - Jan Červený
- Laboratory of Adaptive BiotechnologiesGlobal Change Research Institute CASBrnoCzech Republic
| |
Collapse
|
28
|
Navigating the fitness landscape using multiallele genome editing. Proc Natl Acad Sci U S A 2018; 115:12547-12549. [PMID: 30463944 DOI: 10.1073/pnas.1818285115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
29
|
Growth of Cyanobacteria Is Constrained by the Abundance of Light and Carbon Assimilation Proteins. Cell Rep 2018; 25:478-486.e8. [DOI: 10.1016/j.celrep.2018.09.040] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/13/2018] [Accepted: 09/11/2018] [Indexed: 11/20/2022] Open
|
30
|
Lowit A, Marchetti A, Corson S, Kuschmann A. Rhythmic performance in hypokinetic dysarthria: Relationship between reading, spontaneous speech and diadochokinetic tasks. JOURNAL OF COMMUNICATION DISORDERS 2018; 72:26-39. [PMID: 29471176 PMCID: PMC5883324 DOI: 10.1016/j.jcomdis.2018.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 12/30/2017] [Accepted: 02/09/2018] [Indexed: 06/01/2023]
Abstract
•We investigated speech rhythm in people with Parkinson’s Disease (PwPD) and controls. •Even mildly affected PwPD differed from controls in their rhythmic performance. •PwPD showed less difference between reading and spontaneous speech. •Spontaneous speech highlighted more differences between speakers than reading. •DDK performance did not relate to rhythmic behaviour in connected speech.
Collapse
Affiliation(s)
- Anja Lowit
- School of Psychological Sciences and Health, Graham Hills Building, Strathclyde University, 40 George Street, Glasgow G1 1QE Scotland, United Kingdom.
| | - Agata Marchetti
- School of Psychological Sciences and Health, Strathclyde University, Psychological Sciences and Health, United Kingdom
| | - Stephen Corson
- Dept. of Mathematics and Statistics, Strathclyde University, United Kingdom
| | - Anja Kuschmann
- School of Psychological Sciences and Health, Strathclyde University, Psychological Sciences and Health, United Kingdom
| |
Collapse
|
31
|
A model of optimal protein allocation during phototrophic growth. Biosystems 2018; 166:26-36. [PMID: 29476802 DOI: 10.1016/j.biosystems.2018.02.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 02/05/2018] [Accepted: 02/19/2018] [Indexed: 01/06/2023]
Abstract
Photoautotrophic growth depends upon an optimal allocation of finite cellular resources to diverse intracellular processes. Commitment of a certain mass fraction of the proteome to a specific cellular function typically reduces the proteome available for other cellular functions. Here, we develop a semi-quantitative kinetic model of cyanobacterial phototrophic growth to describe such trade-offs of cellular protein allocation. The model is based on coarse-grained descriptions of key cellular processes, in particular carbon uptake, metabolism, photosynthesis, and protein translation. The model is parameterized using literature data and experimentally obtained growth curves. Of particular interest are the resulting cyanobacterial growth laws as fundamental characteristics of cellular growth. We show that the model gives rise to similar growth laws as observed for heterotrophic organisms, with several important differences due to the distinction between light energy and carbon uptake. We discuss recent experimental data supporting the model results and show that coarse-grained growth models have implications for our understanding of the limits of phototrophic growth and bridge a gap between molecular physiology and ecology.
Collapse
|
32
|
Adjustments to Photosystem Stoichiometry and Electron Transfer Proteins Are Key to the Remarkably Fast Growth of the Cyanobacterium Synechococcus elongatus UTEX 2973. mBio 2018; 9:mBio.02327-17. [PMID: 29437923 PMCID: PMC5801466 DOI: 10.1128/mbio.02327-17] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
At the genome level, Synechococcus elongatus UTEX 2973 (Synechococcus 2973) is nearly identical to the model cyanobacterium Synechococcus elongatus PCC 7942 (Synechococcus 7942) with only 55 single nucleotide differences separating the two strains. Despite the high similarity between the two strains, Synechococcus 2973 grows three times faster, accumulates significantly more glycogen, is tolerant to extremely high light intensities, and displays higher photosynthetic rates. The high homology between the two strains provides a unique opportunity to examine the factors that lead to increased photosynthetic rates. We compared the photophysiology of the two strains and determined the differences in Synechococcus 2973 that lead to increased photosynthetic rates and the concomitant increase in biomass production. In this study, we identified inefficiencies in the electron transport chain of Synechococcus 7942 that have been alleviated in Synechococcus 2973. Photosystem II (PSII) capacity is the same in both strains. However, Synechococcus 2973 exhibits a 1.6-fold increase in PSI content, a 1.5-fold increase in cytochrome b6f content, and a 2.4-fold increase in plastocyanin content on a per cell basis. The increased content of electron carriers allows a higher flux of electrons through the photosynthetic electron transport chain, while the increased PSI content provides more oxidizing power to maintain upstream carriers ready to accept electrons. These changes serve to increase the photosynthetic efficiency of Synechococcus 2973, the fastest growing cyanobacterium known.IMPORTANCE As the global population increases, the amount of arable land continues to decrease. To prevent a looming food crisis, crop productivity per acre must increase. A promising target for improving crop productivity is increasing the photosynthetic rates in crop plants. Cyanobacteria serve as models for higher plant photosynthetic systems and are an important test bed for improvements in photosynthetic productivity. In this study, we identified key factors that lead to improved photosynthetic efficiency and increased production of biomass of a cyanobacterium. We suggest that the findings presented herein will give direction to improvements that may be made in other photosynthetic organisms to improve photosynthetic efficiency.
Collapse
|
33
|
Production of Bioplastic Compounds by Genetically Manipulated and Metabolic Engineered Cyanobacteria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1080:155-169. [DOI: 10.1007/978-981-13-0854-3_7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
34
|
Piechura JR, Amarnath K, O'Shea EK. Natural changes in light interact with circadian regulation at promoters to control gene expression in cyanobacteria. eLife 2017; 6:32032. [PMID: 29239721 PMCID: PMC5785211 DOI: 10.7554/elife.32032] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/13/2017] [Indexed: 12/31/2022] Open
Abstract
The circadian clock interacts with other regulatory pathways to tune physiology to predictable daily changes and unexpected environmental fluctuations. However, the complexity of circadian clocks in higher organisms has prevented a clear understanding of how natural environmental conditions affect circadian clocks and their physiological outputs. Here, we dissect the interaction between circadian regulation and responses to fluctuating light in the cyanobacterium Synechococcus elongatus. We demonstrate that natural changes in light intensity substantially affect the expression of hundreds of circadian-clock-controlled genes, many of which are involved in key steps of metabolism. These changes in expression arise from circadian and light-responsive control of RNA polymerase recruitment to promoters by a network of transcription factors including RpaA and RpaB. Using phenomenological modeling constrained by our data, we reveal simple principles that underlie the small number of stereotyped responses of dusk circadian genes to changes in light. Living things face daily, predictable challenges due to the regular day and night cycle imposed by the Earth’s rotation. Many of them have evolved an internal ‘circadian’ clock to anticipate daily changes in the environment. However, nature can also change in unpredictable ways, and in order to survive, organisms must account for both the time of day stipulated by their clocks and changes in their present environment. For example, cyanobacteria depend on the sun for survival and must cope with light variations throughout the day and the absence of light at nighttime. Circadian clocks are made up of specific genes and their proteins. Most of what we know about how these clocks control the behavior of an organism comes from experiments performed under constant conditions. Previous research has shown that under such circumstances, the circadian clock of cyanobacteria periodically turns on a set of genes every 24 hours via a protein called RpaA. However, to understand how cyanobacteria use this clock, we must know how it works in a fluctuating environment. To test this, Piechura, Amarnath and O’Shea measured the activation of genes in cyanobacteria that had been exposed to changes in light mimicking those in nature. Compared to constant conditions, fluctuating light drastically changed the timing of activation of circadian genes. When light decreased – as it would in nature during sunset or if a cloud blocks the sun – the circadian genes were activated. Changes in light did not change the ‘ticking’ of the clock, but did affect the ability of RpaA to turn on circadian genes. Moreover, the activity of a second protein called RpaB increased when light decreased and the genes were activated. Thus, cyanobacteria switch on circadian genes as the sun is setting or during unexpected shade, likely through RpaA and RpaB, to help them survive without light. This study shows that circadian clocks activate genes differently in the real world compared to unnatural, constant conditions. This may prompt scientists to think carefully about how an organism’s natural environment can affect its inner workings. A next step will be to see how else light affects circadian gene levels. A deeper understanding of how cyanobacteria control their genes in a natural environment will be useful for scientists who engineer these organisms to produce biofuels from sunlight.
Collapse
Affiliation(s)
- Joseph Robert Piechura
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States.,FAS Center for Systems Biology, Harvard University, Cambridge, United States.,Howard Hughes Medical Institute, Harvard University, Cambridge, United States
| | - Kapil Amarnath
- FAS Center for Systems Biology, Harvard University, Cambridge, United States.,Howard Hughes Medical Institute, Harvard University, Cambridge, United States
| | - Erin K O'Shea
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States.,FAS Center for Systems Biology, Harvard University, Cambridge, United States.,Howard Hughes Medical Institute, Harvard University, Cambridge, United States.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, United States
| |
Collapse
|
35
|
Metabolic Flexibility Underpins Growth Capabilities of the Fastest Growing Alga. Curr Biol 2017; 27:2559-2567.e3. [PMID: 28803869 DOI: 10.1016/j.cub.2017.07.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 07/02/2017] [Accepted: 07/06/2017] [Indexed: 11/21/2022]
Abstract
The factors rate-limiting growth of photosynthetic organisms under optimal conditions are controversial [1-8]. Adaptation to extreme environments is usually accompanied by reduced performance under optimal conditions [9, 10]. However, the green alga Chlorella ohadii, isolated from a harsh desert biological soil crust [11-17], does not obey this rule. In addition to resistance to photodamage [17, 18], it performs the fastest growth ever reported for photosynthetic eukaryotes. A multiphasic growth pattern (very fast growth [phase I], followed by growth retardation [phase II] and additional fast growth [phase III]) observed under constant illumination and temperature indicates synchronization of the algal population. Large physiological changes at transitions between growth phases suggest metabolic shifts. Indeed, metabolome analyses at points along the growth phases revealed large changes in the levels of many metabolites during growth with an overall rise during phase I and decline in phase II. Multivariate analysis of the metabolome data highlighted growth phase as the main factor contributing to observed metabolite variance. The analyses identified putrescine as the strongest predictive metabolite for growth phase and a putative growth regulator. Indeed, extracellular additions of polyamines strongly affected the growth rate in phase I and the growth arrest in phase II, with a marked effect on O2 exchange. Our data implicate polyamines as the signals harmonizing metabolic shifts and suggest that metabolic flexibility enables the immense growth capabilities of C. ohadii. The data provide a new dimension to current models focusing on growth-limiting processes in photosynthetic organisms where the anabolic and catabolic metabolisms must be strictly regulated.
Collapse
|
36
|
Esteves-Ferreira AA, Inaba M, Obata T, Fort A, Fleming GTA, Araújo WL, Fernie AR, Sulpice R. A Novel Mechanism, Linked to Cell Density, Largely Controls Cell Division in Synechocystis. PLANT PHYSIOLOGY 2017; 174:2166-2182. [PMID: 28646084 PMCID: PMC5543973 DOI: 10.1104/pp.17.00729] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 06/20/2017] [Indexed: 05/28/2023]
Abstract
Many studies have investigated the various genetic and environmental factors regulating cyanobacterial growth. Here, we investigated the growth and metabolism of Synechocystis sp. PCC 6803 under different nitrogen sources, light intensities, and CO2 concentrations. Cells grown on urea showed the highest growth rates. However, for all conditions tested, the daily growth rates in batch cultures decreased steadily over time, and stationary phase was obtained with similar cell densities. Unexpectedly, metabolic and physiological analyses showed that growth rates during log phase were not controlled primarily by the availability of photoassimilates. Further physiological investigations indicated that nutrient limitation, quorum sensing, light quality, and light intensity (self-shading) were not the main factors responsible for the decrease in the growth rate and the onset of the stationary phase. Moreover, cell division rates in fed-batch cultures were positively correlated with the dilution rates. Hence, not only light, CO2, and nutrients can affect growth but also a cell-cell interaction. Accordingly, we propose that cell-cell interaction may be a factor responsible for the gradual decrease of growth rates in batch cultures during log phase, culminating with the onset of stationary phase.
Collapse
Affiliation(s)
- Alberto A Esteves-Ferreira
- National University of Ireland-Galway, Plant Systems Biology Laboratory, Plant and AgriBiosciences Research Centre, School of Natural Sciences, Galway, Ireland
- CAPES Foundation, Ministry of Education of Brazil, Brasilia DF 70040 020, Brazil
| | - Masami Inaba
- National University of Ireland-Galway, Plant Systems Biology Laboratory, Plant and AgriBiosciences Research Centre, School of Natural Sciences, Galway, Ireland
| | - Toshihiro Obata
- Central Metabolism Laboratory, Department of Molecular Physiology, Max Planck Institute of Molecular Plant Physiology, Max Planck Society, 14476 Potsdam-Golm, Germany
| | - Antoine Fort
- National University of Ireland-Galway, Genetics and Biotechnology Research Laboratory, Plant and AgriBiosciences Research Centre, School of Natural Sciences, Galway, Ireland
| | - Gerard T A Fleming
- National University of Ireland-Galway, Microbiology, School of Natural Sciences, Galway, Ireland
| | - Wagner L Araújo
- Max-Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-900 Vicosa, Minas Gerais, Brazil
| | - Alisdair R Fernie
- Central Metabolism Laboratory, Department of Molecular Physiology, Max Planck Institute of Molecular Plant Physiology, Max Planck Society, 14476 Potsdam-Golm, Germany
| | - Ronan Sulpice
- National University of Ireland-Galway, Plant Systems Biology Laboratory, Plant and AgriBiosciences Research Centre, School of Natural Sciences, Galway, Ireland
| |
Collapse
|
37
|
Cellular trade-offs and optimal resource allocation during cyanobacterial diurnal growth. Proc Natl Acad Sci U S A 2017; 114:E6457-E6465. [PMID: 28720699 DOI: 10.1073/pnas.1617508114] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Cyanobacteria are an integral part of Earth's biogeochemical cycles and a promising resource for the synthesis of renewable bioproducts from atmospheric CO2 Growth and metabolism of cyanobacteria are inherently tied to the diurnal rhythm of light availability. As yet, however, insight into the stoichiometric and energetic constraints of cyanobacterial diurnal growth is limited. Here, we develop a computational framework to investigate the optimal allocation of cellular resources during diurnal phototrophic growth using a genome-scale metabolic reconstruction of the cyanobacterium Synechococcus elongatus PCC 7942. We formulate phototrophic growth as an autocatalytic process and solve the resulting time-dependent resource allocation problem using constraint-based analysis. Based on a narrow and well-defined set of parameters, our approach results in an ab initio prediction of growth properties over a full diurnal cycle. The computational model allows us to study the optimality of metabolite partitioning during diurnal growth. The cyclic pattern of glycogen accumulation, an emergent property of the model, has timing characteristics that are in qualitative agreement with experimental findings. The approach presented here provides insight into the time-dependent resource allocation problem of phototrophic diurnal growth and may serve as a general framework to assess the optimality of metabolic strategies that evolved in phototrophic organisms under diurnal conditions.
Collapse
|
38
|
Du W, Angermayr SA, Jongbloets JA, Molenaar D, Bachmann H, Hellingwerf KJ, Branco dos Santos F. Nonhierarchical Flux Regulation Exposes the Fitness Burden Associated with Lactate Production in Synechocystis sp. PCC6803. ACS Synth Biol 2017; 6:395-401. [PMID: 27936615 DOI: 10.1021/acssynbio.6b00235] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cyanobacteria are mostly engineered to be sustainable cell-factories by genetic manipulations alone. Here, by modulating the concentration of allosteric effectors, we focus on increasing product formation without further burdening the cells with increased expression of enzymes. Resorting to a novel 96-well microplate cultivation system for cyanobacteria, and using lactate-producing strains of Synechocystis PCC6803 expressing different l-lactate dehydrogenases (LDH), we titrated the effect of 2,5-anhydro-mannitol supplementation. The latter acts in cells as a nonmetabolizable analogue of fructose 1,6-bisphosphate, a known allosteric regulator of one of the tested LDHs. In this strain (SAA023), we achieved over 2-fold increase of lactate productivity. Furthermore, we observed that as carbon is increasingly deviated during growth toward product formation, there is an increased fixation rate in the population of spontaneous mutants harboring an impaired production pathway. This is a challenge in the development of green cell factories, which may be countered by the incorporation in biotechnological processes of strategies such as the one pioneered here.
Collapse
Affiliation(s)
- Wei Du
- Molecular
Microbial Physiology Group, Faculty of Science, Swammerdam Institute
for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - S. Andreas Angermayr
- Molecular
Microbial Physiology Group, Faculty of Science, Swammerdam Institute
for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Joeri A. Jongbloets
- Molecular
Microbial Physiology Group, Faculty of Science, Swammerdam Institute
for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Douwe Molenaar
- Systems
Bioinformatics, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Herwig Bachmann
- Systems
Bioinformatics, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Klaas J. Hellingwerf
- Molecular
Microbial Physiology Group, Faculty of Science, Swammerdam Institute
for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Filipe Branco dos Santos
- Molecular
Microbial Physiology Group, Faculty of Science, Swammerdam Institute
for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| |
Collapse
|
39
|
Westermark S, Steuer R. Toward Multiscale Models of Cyanobacterial Growth: A Modular Approach. Front Bioeng Biotechnol 2016; 4:95. [PMID: 28083530 PMCID: PMC5183639 DOI: 10.3389/fbioe.2016.00095] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 12/09/2016] [Indexed: 11/29/2022] Open
Abstract
Oxygenic photosynthesis dominates global primary productivity ever since its evolution more than three billion years ago. While many aspects of phototrophic growth are well understood, it remains a considerable challenge to elucidate the manifold dependencies and interconnections between the diverse cellular processes that together facilitate the synthesis of new cells. Phototrophic growth involves the coordinated action of several layers of cellular functioning, ranging from the photosynthetic light reactions and the electron transport chain, to carbon-concentrating mechanisms and the assimilation of inorganic carbon. It requires the synthesis of new building blocks by cellular metabolism, protection against excessive light, as well as diurnal regulation by a circadian clock and the orchestration of gene expression and cell division. Computational modeling allows us to quantitatively describe these cellular functions and processes relevant for phototrophic growth. As yet, however, computational models are mostly confined to the inner workings of individual cellular processes, rather than describing the manifold interactions between them in the context of a living cell. Using cyanobacteria as model organisms, this contribution seeks to summarize existing computational models that are relevant to describe phototrophic growth and seeks to outline their interactions and dependencies. Our ultimate aim is to understand cellular functioning and growth as the outcome of a coordinated operation of diverse yet interconnected cellular processes.
Collapse
Affiliation(s)
- Stefanie Westermark
- Fachinstitut für Theoretische Biologie (ITB), Institut für Biologie, Humboldt-Universität zu Berlin , Berlin , Germany
| | - Ralf Steuer
- Fachinstitut für Theoretische Biologie (ITB), Institut für Biologie, Humboldt-Universität zu Berlin , Berlin , Germany
| |
Collapse
|
40
|
Ardell DH, Hou YM. Initiator tRNA genes template the 3' CCA end at high frequencies in bacteria. BMC Genomics 2016; 17:1003. [PMID: 27927177 PMCID: PMC5143459 DOI: 10.1186/s12864-016-3314-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 11/18/2016] [Indexed: 01/06/2023] Open
Abstract
Background While the CCA sequence at the mature 3′ end of tRNAs is conserved and critical for translational function, a genetic template for this sequence is not always contained in tRNA genes. In eukaryotes and Archaea, the CCA ends of tRNAs are synthesized post-transcriptionally by CCA-adding enzymes. In Bacteria, tRNA genes template CCA sporadically. Results In order to understand the variation in how prokaryotic tRNA genes template CCA, we re-annotated tRNA genes in tRNAdb-CE database version 0.8. Among 132,129 prokaryotic tRNA genes, initiator tRNA genes template CCA at the highest average frequency (74.1%) over all functional classes except selenocysteine and pyrrolysine tRNA genes (88.1% and 100% respectively). Across bacterial phyla and a wide range of genome sizes, many lineages exist in which predominantly initiator tRNA genes template CCA. Convergent and parallel retention of CCA templating in initiator tRNA genes evolved in independent histories of reductive genome evolution in Bacteria. Also, in a majority of cyanobacterial and actinobacterial genera, predominantly initiator tRNA genes template CCA. We also found that a surprising fraction of archaeal tRNA genes template CCA. Conclusions We suggest that cotranscriptional synthesis of initiator tRNA CCA 3′ ends can complement inefficient processing of initiator tRNA precursors, “bootstrap” rapid initiation of protein synthesis from a non-growing state, or contribute to an increase in cellular growth rates by reducing overheads of mass and energy to maintain nonfunctional tRNA precursor pools. More generally, CCA templating in structurally non-conforming tRNA genes can afford cells robustness and greater plasticity to respond rapidly to environmental changes and stimuli. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3314-x) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- David H Ardell
- Program in Quantitative and Systems Biology, University of California, 5200 North Lake Road, CA, 95343, Merced, USA. .,Molecular and Cell Biology Unit, School of Natural Sciences, University of California, 5200 North Lake Road, Merced, CA, 95343, USA.
| | - Ya-Ming Hou
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 233 South 10th Street, BLSB 220, Philadelphia, PA, 19107, USA
| |
Collapse
|
41
|
Du W, Jongbloets JA, Pineda Hernández H, Bruggeman FJ, Hellingwerf KJ, Branco dos Santos F. Photonfluxostat: A method for light-limited batch cultivation of cyanobacteria at different, yet constant, growth rates. ALGAL RES 2016. [DOI: 10.1016/j.algal.2016.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
42
|
Abramson BW, Kachel B, Kramer DM, Ducat DC. Increased Photochemical Efficiency in Cyanobacteria via an Engineered Sucrose Sink. PLANT & CELL PHYSIOLOGY 2016; 57:2451-2460. [PMID: 27742883 DOI: 10.1093/pcp/pcw169] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 09/25/2016] [Indexed: 06/06/2023]
Abstract
In plants, a limited capacity to utilize or export the end-products of the Calvin-Benson cycle (CB) from photosynthetically active source cells to non-photosynthetic sink cells can result in reduced carbon capture and photosynthetic electron transport (PET), and lowered photochemical efficiency. The down-regulation of photosynthesis caused by reduced capacity to utilize photosynthate has been termed 'sink limitation'. Recently, several cyanobacterial and algal strains engineered to overproduce target metabolites have exhibited increased photochemistry, suggesting that possible source-sink regulatory mechanisms may be involved. We directly examined photochemical properties following induction of a heterologous sucrose 'sink' in the unicellular cyanobacterium Synechococcus elongatus PCC 7942. We show that total photochemistry increases proportionally to the experimentally controlled rate of sucrose export. Importantly, the quantum yield of PSII (ΦII) increases in response to sucrose export while the PET chain becomes more oxidized from less PSI acceptor-side limitation, suggesting increased CB activity and a decrease in sink limitation. Enhanced photosynthetic activity and linear electron flow are detectable within hours of induction of the heterologous sink and are independent of pigmentation alterations or the ionic/osmotic effects of the induction system. These observations provide direct evidence that secretion of heterologous carbon bioproducts can be used as an alternative approach to improve photosynthetic efficiency, presumably by by-passing sink limitation. Our results also suggest that engineered microalgal production strains are valuable alternative models for examining photosynthetic sink limitation because they enable greater control and monitoring of metabolite fluxes relative to plants.
Collapse
Affiliation(s)
- Bradley W Abramson
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
- Department of Cell and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Benjamin Kachel
- Department of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - David M Kramer
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Daniel C Ducat
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| |
Collapse
|
43
|
Nigita G, Acunzo M, Romano G, Veneziano D, Laganà A, Vitiello M, Wernicke D, Ferro A, Croce CM. microRNA editing in seed region aligns with cellular changes in hypoxic conditions. Nucleic Acids Res 2016; 44:6298-308. [PMID: 27298257 PMCID: PMC4994866 DOI: 10.1093/nar/gkw532] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 05/31/2016] [Accepted: 06/01/2016] [Indexed: 12/22/2022] Open
Abstract
RNA editing is a finely tuned, dynamic mechanism for post-transcriptional gene regulation that has been thoroughly investigated in the last decade. Nevertheless, RNA editing in non-coding RNA, such as microRNA (miRNA), have caused great debate and have called for deeper investigation. Until recently, in fact, inadequate methodologies and experimental contexts have been unable to provide detailed insights for further elucidation of RNA editing affecting miRNAs, especially in cancer.In this work, we leverage on recent innovative bioinformatics approaches applied to a more informative experimental context in order to analyze the variations in miRNA seed region editing activity during a time course of a hypoxia-exposed breast cancer cell line. By investigating its behavior in a dynamic context, we found that miRNA editing events in the seed region are not depended on miRNA expression, unprecedentedly providing insights on the targetome shifts derived from these modifications. This reveals that miRNA editing acts under the influence of environmentally induced stimuli.Our results show a miRNA editing activity trend aligning with cellular pathways closely associated to hypoxia, such as the VEGF and PI3K/Akt pathways, providing important novel insights on this poorly elucidated phenomenon.
Collapse
Affiliation(s)
- Giovanni Nigita
- Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA
| | - Mario Acunzo
- Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA
| | - Giulia Romano
- Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA
| | - Dario Veneziano
- Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA
| | - Alessandro Laganà
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York City, NY 10029, USA
| | - Marika Vitiello
- Department of Clinicaland Molecular Biomedicine, University of Catania, Catania 95125, Italy
| | - Dorothee Wernicke
- Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA
| | - Alfredo Ferro
- Department of Structural & Functional Biology, University 'Federico II' of Naples, Naples 80126, Italy
| | - Carlo M Croce
- Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA
| |
Collapse
|
44
|
Unlocking the Constraints of Cyanobacterial Productivity: Acclimations Enabling Ultrafast Growth. mBio 2016; 7:mBio.00949-16. [PMID: 27460798 PMCID: PMC4981716 DOI: 10.1128/mbio.00949-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Harnessing the metabolic potential of photosynthetic microbes for next-generation biotechnology objectives requires detailed scientific understanding of the physiological constraints and regulatory controls affecting carbon partitioning between biomass, metabolite storage pools, and bioproduct synthesis. We dissected the cellular mechanisms underlying the remarkable physiological robustness of the euryhaline unicellular cyanobacterium Synechococcus sp. strain PCC 7002 (Synechococcus 7002) and identify key mechanisms that allow cyanobacteria to achieve unprecedented photoautotrophic productivities (~2.5-h doubling time). Ultrafast growth of Synechococcus 7002 was supported by high rates of photosynthetic electron transfer and linked to significantly elevated transcription of precursor biosynthesis and protein translation machinery. Notably, no growth or photosynthesis inhibition signatures were observed under any of the tested experimental conditions. Finally, the ultrafast growth in Synechococcus 7002 was also linked to a 300% expansion of average cell volume. We hypothesize that this cellular adaptation is required at high irradiances to support higher cell division rates and reduce deleterious effects, corresponding to high light, through increased carbon and reductant sequestration. Efficient coupling between photosynthesis and productivity is central to the development of biotechnology based on solar energy. Therefore, understanding the factors constraining maximum rates of carbon processing is necessary to identify regulatory mechanisms and devise strategies to overcome productivity constraints. Here, we interrogate the molecular mechanisms that operate at a systems level to allow cyanobacteria to achieve ultrafast growth. This was done by considering growth and photosynthetic kinetics with global transcription patterns. We have delineated putative biological principles that allow unicellular cyanobacteria to achieve ultrahigh growth rates through photophysiological acclimation and effective management of cellular resource under different growth regimes.
Collapse
|
45
|
Evolutionary tradeoffs in cellular composition across diverse bacteria. ISME JOURNAL 2016; 10:2145-57. [PMID: 27046336 PMCID: PMC4989312 DOI: 10.1038/ismej.2016.21] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 01/11/2016] [Accepted: 01/16/2016] [Indexed: 12/23/2022]
Abstract
One of the most important classic and contemporary interests in biology is the connection between cellular composition and physiological function. Decades of research have allowed us to understand the detailed relationship between various cellular components and processes for individual species, and have uncovered common functionality across diverse species. However, there still remains the need for frameworks that can mechanistically predict the tradeoffs between cellular functions and elucidate and interpret average trends across species. Here we provide a comprehensive analysis of how cellular composition changes across the diversity of bacteria as connected with physiological function and metabolism, spanning five orders of magnitude in body size. We present an analysis of the trends with cell volume that covers shifts in genomic, protein, cellular envelope, RNA and ribosomal content. We show that trends in protein content are more complex than a simple proportionality with the overall genome size, and that the number of ribosomes is simply explained by cross-species shifts in biosynthesis requirements. Furthermore, we show that the largest and smallest bacteria are limited by physical space requirements. At the lower end of size, cell volume is dominated by DNA and protein content—the requirement for which predicts a lower limit on cell size that is in good agreement with the smallest observed bacteria. At the upper end of bacterial size, we have identified a point at which the number of ribosomes required for biosynthesis exceeds available cell volume. Between these limits we are able to discuss systematic and dramatic shifts in cellular composition. Much of our analysis is connected with the basic energetics of cells where we show that the scaling of metabolic rate is surprisingly superlinear with all cellular components.
Collapse
|
46
|
Raanan H, Oren N, Treves H, Berkowicz SM, Hagemann M, Pade N, Keren N, Kaplan A. Simulated soil crust conditions in a chamber system provide new insights on cyanobacterial acclimation to desiccation. Environ Microbiol 2015; 18:414-26. [PMID: 26234786 DOI: 10.1111/1462-2920.12998] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Environmental research often faces two major hurdles: (i) fluctuating spatial and temporal conditions and consequently large variability in the organisms' abundance and performance, and (ii) complex, costly logistics involved in field experiments. Measurements of physiological parameters or molecular analyses often represent single shot experiments. To study desiccation acclimation of filamentous cyanobacteria, the founders and main primary producers in desert biological soil crusts (BSC), we constructed an environmental chamber that can reproducibly and accurately simulate ambient conditions and measure microorganism performance. We show that recovery from desiccation of BSC cyanobacteria and Leptolyngbya ohadii isolated thereof are strongly affected by dehydration rate following morning dew. This effect is most pronounced in cells exposed to high light and temperature in the dry phase. Simultaneous measurements of water content, gas exchange and fluorescence were performed during dehydration. Photosynthetic performance measured by fluorescence begins declining when light intensity reaches values above 100 μmol photons m(-2) s(-1), even in fully hydrated cells. In contrast, photosynthetic rates measured using O2 evolution and CO2 uptake increased during rising irradiance to the point where the water content declined below ∼ 50%. Thus, fluorescence cannot serve as a reliable measure of photosynthesis in desert cyanobacteria. The effects of drying on gas exchange are discussed.
Collapse
Affiliation(s)
- Hagai Raanan
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Nadav Oren
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Haim Treves
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Simon M Berkowicz
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.,Arid Ecosystems Research Center, Edmond J. Safra Campus, Givat Ram, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Martin Hagemann
- Institut für Biowissenschaften, Abteilung Pflanzenphysiologie, Universität Rostock, A.-Einstein-Str. 3, Rostock, D-18059, Germany
| | - Nadin Pade
- Institut für Biowissenschaften, Abteilung Pflanzenphysiologie, Universität Rostock, A.-Einstein-Str. 3, Rostock, D-18059, Germany
| | - Nir Keren
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.,Arid Ecosystems Research Center, Edmond J. Safra Campus, Givat Ram, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| |
Collapse
|