1
|
Joris P, Lombard E, Paillet A, Navarro G, Guillouet SE, Gorret N. Recycling Potential of Cupriavidus necator for Life support in Space: Production of SCPs from Volatile Fatty Acid and Urea mixture. J Biotechnol 2024:S0168-1656(24)00264-5. [PMID: 39396642 DOI: 10.1016/j.jbiotec.2024.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2024] [Revised: 10/02/2024] [Accepted: 10/04/2024] [Indexed: 10/15/2024]
Abstract
The International Space Station currently requires four annual replenishments for food supply, a practice that won't be feasible for deep space missions due to the greater distances. Based on the design of closed ecological life support systems, two waste streams were identified: urea from the crew urine, volatile fatty acids (VFAs) from a first stage of anaerobic digestion of waste. The objective of this study was to assess the ability of bacterium Cupriavidus necator to produce single cell protein on urea and VFAs. Thus, the effect of carbon sources (glucose vs VFAs) and the dilution rate on the biomass composition was determined in continuous cultures. Complete transformation of the carbon source into protein-rich biomass was achieved up to 78% cell dry weight (CDW). For both carbon sources, the protein content increased from 55.0%CDW to 78%CDW with a decrease in the dilution rate. Conversely, the nucleic acid and polyhydroxyalkanoate contents decreased with the dilution rate from 8.8%CDW to 4.8%CDW and 9.8%CDW to 0.6%CDW respectively. Working at a low dilution rate seems to be a good way to maximize protein content while minimizing unwanted nucleic acids and polyhydroxyalkanoates.
Collapse
Affiliation(s)
- P Joris
- TBI, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - E Lombard
- TBI, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - A Paillet
- CNES-Exploration Vols Habités-Spaceship.Fr project, Toulouse, France
| | - G Navarro
- CNES-Exploration Vols Habités-Spaceship.Fr project, Toulouse, France
| | - S E Guillouet
- TBI, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - N Gorret
- TBI, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France.
| |
Collapse
|
2
|
Stuij TM, Cleary DFR, Rocha RJM, Polonia ARM, Machado E Silva DA, Frommlet JC, Louvado A, Huang YM, De Voogd NJ, Gomes NCM. Development and validation of an experimental life support system to study coral reef microbial communities. Sci Rep 2024; 14:21260. [PMID: 39261551 PMCID: PMC11391067 DOI: 10.1038/s41598-024-69514-0] [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: 07/26/2023] [Accepted: 08/06/2024] [Indexed: 09/13/2024] Open
Abstract
In the present study, we developed and validated an experimental life support system (ELSS) designed to investigate coral reef associated bacterial communities. The microcosms in the ELSS consisted of coral reef sediment, synthetic seawater, and specimens of five benthic reef species. These included two hard corals Montipora digitata and Montipora capricornis, a soft coral Sarcophyton glaucum, a zoanthid Zoanthus sp., and a sponge Chondrilla sp.. Physicochemical parameters and bacterial communities in the ELSS were similar to those observed at shallow coral reef sites. Sediment bacterial evenness and higher taxonomic composition were more similar to natural-type communities at days 29 and 34 than at day 8 after transfer to the microcosms, suggesting microbial stabilization after an initial recovery period. Biotopes were compositionally distinct but shared a number of ASVs. At day 34, sediment specific ASVs were found in hosts and visa versa. Transplantation significantly altered the bacterial community composition of M. digitata and Chondrilla sp., suggesting microbial adaptation to altered environmental conditions. Altogether, our results support the suitability of the ELSS developed in this study as a model system to investigate coral reef associated bacterial communities using multi-factorial experiments.
Collapse
Affiliation(s)
- T M Stuij
- Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Campus Universitário Santiago, 3810-193, Aveiro, Portugal.
| | - D F R Cleary
- Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Campus Universitário Santiago, 3810-193, Aveiro, Portugal
| | - R J M Rocha
- Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Campus Universitário Santiago, 3810-193, Aveiro, Portugal
| | - A R M Polonia
- Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Campus Universitário Santiago, 3810-193, Aveiro, Portugal
| | - D A Machado E Silva
- Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Campus Universitário Santiago, 3810-193, Aveiro, Portugal
| | - J C Frommlet
- Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Campus Universitário Santiago, 3810-193, Aveiro, Portugal
| | - A Louvado
- Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Campus Universitário Santiago, 3810-193, Aveiro, Portugal
| | - Y M Huang
- National Penghu University of Science and Technology, Magong, Taiwan
| | - N J De Voogd
- Naturalis Biodiversity Center, Leiden, the Netherlands
- Institute of Biology (IBL), Leiden University, Leiden, the Netherlands
| | - N C M Gomes
- Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Campus Universitário Santiago, 3810-193, Aveiro, Portugal.
| |
Collapse
|
3
|
Huang Y, Mukherjee A, Schink S, Benites NC, Basan M. Evolution and stability of complex microbial communities driven by trade-offs. Mol Syst Biol 2024; 20:997-1005. [PMID: 38961275 PMCID: PMC11369148 DOI: 10.1038/s44320-024-00051-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 06/18/2024] [Accepted: 06/20/2024] [Indexed: 07/05/2024] Open
Abstract
Microbial communities are ubiquitous in nature and play an important role in ecology and human health. Cross-feeding is thought to be core to microbial communities, though it remains unclear precisely why it emerges. Why have multi-species microbial communities evolved in many contexts and what protects microbial consortia from invasion? Here, we review recent insights into the emergence and stability of coexistence in microbial communities. A particular focus is the long-term evolutionary stability of coexistence, as observed for microbial communities that spontaneously evolved in the E. coli long-term evolution experiment (LTEE). We analyze these findings in the context of recent work on trade-offs between competing microbial objectives, which can constitute a mechanistic basis for the emergence of coexistence. Coexisting communities, rather than monocultures of the 'fittest' single strain, can form stable endpoints of evolutionary trajectories. Hence, the emergence of coexistence might be an obligatory outcome in the evolution of microbial communities. This implies that rather than embodying fragile metastable configurations, some microbial communities can constitute formidable ecosystems that are difficult to disrupt.
Collapse
Affiliation(s)
- Yanqing Huang
- Harvard Medical School, Department of Systems Biology, Boston, USA
| | - Avik Mukherjee
- Harvard Medical School, Department of Systems Biology, Boston, USA
| | - Severin Schink
- Harvard Medical School, Department of Systems Biology, Boston, USA
| | | | - Markus Basan
- Harvard Medical School, Department of Systems Biology, Boston, USA.
| |
Collapse
|
4
|
Mukherjee A, Huang Y, Oh S, Sanchez C, Chang YF, Liu X, Bradshaw GA, Benites NC, Paulsson J, Kirschner MW, Sung Y, Elgeti J, Basan M. Homeostasis of cytoplasmic crowding by cell wall fluidization and ribosomal counterions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.31.555748. [PMID: 37808635 PMCID: PMC10557573 DOI: 10.1101/2023.08.31.555748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
In bacteria, algae, fungi, and plant cells, the wall must expand in concert with cytoplasmic biomass production, otherwise cells would experience toxic molecular crowding1,2or lyse. But how cells achieve expansion of this complex biomaterial in coordination with biosynthesis of macromolecules in the cytoplasm remains unexplained3, although recent works have revealed that these processes are indeed coupled4,5. Here, we report a striking increase of turgor pressure with growth rate in E. coli, suggesting that the speed of cell wall expansion is controlled via turgor. Remarkably, despite this increase in turgor pressure, cellular biomass density remains constant across a wide range of growth rates. By contrast, perturbations of turgor pressure that deviate from this scaling directly alter biomass density. A mathematical model based on cell wall fluidization by cell wall endopeptidases not only explains these apparently confounding observations but makes surprising quantitative predictions that we validated experimentally. The picture that emerges is that turgor pressure is directly controlled via counterions of ribosomal RNA. Elegantly, the coupling between rRNA and turgor pressure simultaneously coordinates cell wall expansion across a wide range of growth rates and exerts homeostatic feedback control on biomass density. This mechanism may regulate cell wall biosynthesis from microbes to plants and has important implications for the mechanism of action of antibiotics6.
Collapse
|
5
|
Shin J, Zielinski DC, Palsson BO. Deciphering nutritional stress responses via knowledge-enriched transcriptomics for microbial engineering. Metab Eng 2024; 84:34-47. [PMID: 38825177 DOI: 10.1016/j.ymben.2024.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 03/27/2024] [Accepted: 05/28/2024] [Indexed: 06/04/2024]
Abstract
Understanding diverse bacterial nutritional requirements and responses is foundational in microbial research and biotechnology. In this study, we employed knowledge-enriched transcriptomic analytics to decipher complex stress responses of Vibrio natriegens to supplied nutrients, aiming to enhance microbial engineering efforts. We computed 64 independently modulated gene sets that comprise a quantitative basis for transcriptome dynamics across a comprehensive transcriptomics dataset containing a broad array of nutrient conditions. Our approach led to the i) identification of novel transporter systems for diverse substrates, ii) a detailed understanding of how trace elements affect metabolism and growth, and iii) extensive characterization of nutrient-induced stress responses, including osmotic stress, low glycolytic flux, proteostasis, and altered protein expression. By clarifying the relationship between the acetate-associated regulon and glycolytic flux status of various nutrients, we have showcased its vital role in directing optimal carbon source selection. Our findings offer deep insights into the transcriptional landscape of bacterial nutrition and underscore its significance in tailoring strain engineering strategies, thereby facilitating the development of more efficient and robust microbial systems for biotechnological applications.
Collapse
Affiliation(s)
- Jongoh Shin
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Daniel C Zielinski
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Bernhard O Palsson
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, 2800, Denmark; Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA.
| |
Collapse
|
6
|
Lara AR, Kunert F, Vandenbroucke V, Taymaz-Nikerel H, Martínez LM, Sigala JC, Delvigne F, Gosset G, Büchs J. Transport-controlled growth decoupling for self-induced protein expression with a glycerol-repressible genetic circuit. Biotechnol Bioeng 2024; 121:1789-1802. [PMID: 38470342 DOI: 10.1002/bit.28697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/17/2024] [Accepted: 03/01/2024] [Indexed: 03/13/2024]
Abstract
Decoupling cell formation from recombinant protein synthesis is a potent strategy to intensify bioprocesses. Escherichia coli strains with mutations in the glucose uptake components lack catabolite repression, display low growth rate, no overflow metabolism, and high recombinant protein yields. Fast growth rates were promoted by the simultaneous consumption of glucose and glycerol, and this was followed by a phase of slow growth, when only glucose remained in the medium. A glycerol-repressible genetic circuit was designed to autonomously induce recombinant protein expression. The engineered strain bearing the genetic circuit was cultured in 3.9 g L-1 glycerol + 18 g L-1 glucose in microbioreactors with online oxygen transfer rate monitoring. The growth was fast during the simultaneous consumption of both carbon sources (C-sources), while expression of the recombinant protein was low. When glycerol was depleted, the growth rate decreased, and the specific fluorescence reached values 17% higher than those obtained with a strong constitutive promoter. Despite the relatively high amount of C-source used, no oxygen limitation was observed. The proposed approach eliminates the need for the substrate feeding or inducers addition and is set as a simple batch culture while mimicking fed-batch performance.
Collapse
Affiliation(s)
- Alvaro R Lara
- Department of Biological and Chemical Engineering, Aarhus University, Aarhus, Denmark
| | - Flavio Kunert
- Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Aachen, Germany
| | - Vincent Vandenbroucke
- Terra Research and Teaching Centre, Microbial Processes and Interactions (MiPI), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Hilal Taymaz-Nikerel
- Department of Genetics and Bioengineering, Istanbul Bilgi University, Istanbul, Turkey
| | - Luz María Martínez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Juan-Carlos Sigala
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana, Ciudad de México, México
| | - Frank Delvigne
- Terra Research and Teaching Centre, Microbial Processes and Interactions (MiPI), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Guillermo Gosset
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Jochen Büchs
- Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Aachen, Germany
| |
Collapse
|
7
|
Zhu M, Dai X. Shaping of microbial phenotypes by trade-offs. Nat Commun 2024; 15:4238. [PMID: 38762599 PMCID: PMC11102524 DOI: 10.1038/s41467-024-48591-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 05/06/2024] [Indexed: 05/20/2024] Open
Abstract
Growth rate maximization is an important fitness strategy for microbes. However, the wide distribution of slow-growing oligotrophic microbes in ecosystems suggests that rapid growth is often not favored across ecological environments. In many circumstances, there exist trade-offs between growth and other important traits (e.g., adaptability and survival) due to physiological and proteome constraints. Investments on alternative traits could compromise growth rate and microbes need to adopt bet-hedging strategies to improve fitness in fluctuating environments. Here we review the mechanistic role of trade-offs in controlling bacterial growth and further highlight its ecological implications in driving the emergences of many important ecological phenomena such as co-existence, population heterogeneity and oligotrophic/copiotrophic lifestyles.
Collapse
Affiliation(s)
- Manlu Zhu
- State Key Laboratory of Green Pesticide, School of Life Sciences, Central China Normal University, Wuhan, PR China
| | - Xiongfeng Dai
- State Key Laboratory of Green Pesticide, School of Life Sciences, Central China Normal University, Wuhan, PR China.
| |
Collapse
|
8
|
Mori M, Patsalo V, Euler C, Williamson JR, Scott M. Proteome partitioning constraints in long-term laboratory evolution. Nat Commun 2024; 15:4087. [PMID: 38744842 PMCID: PMC11094134 DOI: 10.1038/s41467-024-48447-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 04/26/2024] [Indexed: 05/16/2024] Open
Abstract
Adaptive laboratory evolution experiments provide a controlled context in which the dynamics of selection and adaptation can be followed in real-time at the single-nucleotide level. And yet this precision introduces hundreds of degrees-of-freedom as genetic changes accrue in parallel lineages over generations. On short timescales, physiological constraints have been leveraged to provide a coarse-grained view of bacterial gene expression characterized by a small set of phenomenological parameters. Here, we ask whether this same framework, operating at a level between genotype and fitness, informs physiological changes that occur on evolutionary timescales. Using a strain adapted to growth in glucose minimal medium, we find that the proteome is substantially remodeled over 40 000 generations. The most striking change is an apparent increase in enzyme efficiency, particularly in the enzymes of lower-glycolysis. We propose that deletion of metabolic flux-sensing regulation early in the adaptation results in increased enzyme saturation and can account for the observed proteome remodeling.
Collapse
Affiliation(s)
- Matteo Mori
- Department of Physics, University of California at San Diego, La Jolla, CA, USA
| | - Vadim Patsalo
- Department of Integrative Structural and Computational Biology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Christian Euler
- Department of Chemical Engineering, University of Waterloo, Waterloo, ON, Canada
| | - James R Williamson
- Department of Integrative Structural and Computational Biology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Matthew Scott
- Waterloo Centre for Microbial Research and the Department of Applied Mathematics, University of Waterloo, Waterloo, ON, Canada.
| |
Collapse
|
9
|
Basan M, Mukherjee A, Huang Y, Oh S, Sanchez C, Chang YF, Liu X, Bradshaw G, Benites N, Paulsson J, Kirschner M, Sung Y, Elgeti J. Homeostasis of cytoplasmic crowding by cell wall fluidization and ribosomal counterions. RESEARCH SQUARE 2024:rs.3.rs-4138690. [PMID: 38699329 PMCID: PMC11065075 DOI: 10.21203/rs.3.rs-4138690/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
In bacteria, algae, fungi, and plant cells, the wall must expand in concert with cytoplasmic biomass production, otherwise cells would experience toxic molecular crowding1,2 or lyse. But how cells achieve expansion of this complex biomaterial in coordination with biosynthesis of macromolecules in the cytoplasm remains unexplained3, although recent works have revealed that these processes are indeed coupled4,5. Here, we report a striking increase of turgor pressure with growth rate in E. coli, suggesting that the speed of cell wall expansion is controlled via turgor. Remarkably, despite this increase in turgor pressure, cellular biomass density remains constant across a wide range of growth rates. By contrast, perturbations of turgor pressure that deviate from this scaling directly alter biomass density. A mathematical model based on cell wall fluidization by cell wall endopeptidases not only explains these apparently confounding observations but makes surprising quantitative predictions that we validated experimentally. The picture that emerges is that turgor pressure is directly controlled via counterions of ribosomal RNA. Elegantly, the coupling between rRNA and turgor pressure simultaneously coordinates cell wall expansion across a wide range of growth rates and exerts homeostatic feedback control on biomass density. This mechanism may regulate cell wall biosynthesis from microbes to plants and has important implications for the mechanism of action of antibiotics6.
Collapse
|
10
|
Cai Y, Dong J, Huang J, He J, Hu Y, Sui Z, Tang P. The cyclic AMP (cAMP) phosphodiesterase CpdA required for growth, biofilm formation, motility and pathogenicity of Edwardsiella piscicida. Microb Pathog 2024; 188:106545. [PMID: 38244636 DOI: 10.1016/j.micpath.2024.106545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/09/2024] [Accepted: 01/14/2024] [Indexed: 01/22/2024]
Abstract
Edwardsiella piscicida is a severe fish pathogen with wide host range, causing the huge economic losses in the aquaculture industry. Cyclic adenosine monophosphate (cAMP) as an important second messenger regulates the physiological and behavioral responses to environmental cues in eukaryotic and prokaryotic. The intracellular level of cAMP for effective activity is tightly controlled by the synthesis of adenylate cyclase, excretion and degradation of phosphodiesterase. In this study, we identified and characterized a class III cAMP phosphodiesterase, named as CpdA, in the E. piscicida. To investigate the role of CpdA in the physiology and pathogenicity, we constructed the in-frame deletion mutant of cpdA of E. piscicida, TX01ΔcpdA. The results showed that TX01ΔcpdA accumulated the higher intracellular cAMP concentration than TX01, indicating that CpdA exerted the hydrolysis of cAMP. In addition, compared to the TX01, the TX01ΔcpdA slowed growth rate, diminished biofilm formation and lost motility. More importantly, pathogenicity analysis confirmed that TX01ΔcpdA significantly impaired the ability of invading the epithelial cells, reproduction in macrophages, tissues dissemination and lethality for healthy tilapias. The most of lost properties of TX01ΔcpdA were restored partially or fully by the introduction of cpdA gene. These results suggest that cpdA is required for regulation of the physiology and virulence of E. piscicida.
Collapse
Affiliation(s)
- Yidong Cai
- School of Life and Health, Hainan University, Haikou, 570228, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou, 571101, China
| | - Jinggang Dong
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou, 571101, China
| | - Jianqiang Huang
- Zhanjiang Experimental Station, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, 524013, China
| | - Jiaojiao He
- School of Life and Health, Hainan University, Haikou, 570228, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou, 571101, China
| | - Yonghua Hu
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou, 571101, China; Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Haikou, 571101, China; Zhanjiang Experimental Station, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, 524013, China
| | - Zhihai Sui
- School of Life Science, Linyi University, Linyi, 276000, China.
| | - Ping Tang
- State Key Laboratory of Conservation and Utilization of Biologícal Resources of Yunnan, College of Plant Protection, Yunnan Agricultural University, Kunming, 650201, China.
| |
Collapse
|
11
|
Ugolini GS, Wang M, Secchi E, Pioli R, Ackermann M, Stocker R. Microfluidic approaches in microbial ecology. LAB ON A CHIP 2024; 24:1394-1418. [PMID: 38344937 PMCID: PMC10898419 DOI: 10.1039/d3lc00784g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Microbial life is at the heart of many diverse environments and regulates most natural processes, from the functioning of animal organs to the cycling of global carbon. Yet, the study of microbial ecology is often limited by challenges in visualizing microbial processes and replicating the environmental conditions under which they unfold. Microfluidics operates at the characteristic scale at which microorganisms live and perform their functions, thus allowing for the observation and quantification of behaviors such as growth, motility, and responses to external cues, often with greater detail than classical techniques. By enabling a high degree of control in space and time of environmental conditions such as nutrient gradients, pH levels, and fluid flow patterns, microfluidics further provides the opportunity to study microbial processes in conditions that mimic the natural settings harboring microbial life. In this review, we describe how recent applications of microfluidic systems to microbial ecology have enriched our understanding of microbial life and microbial communities. We highlight discoveries enabled by microfluidic approaches ranging from single-cell behaviors to the functioning of multi-cellular communities, and we indicate potential future opportunities to use microfluidics to further advance our understanding of microbial processes and their implications.
Collapse
Affiliation(s)
- Giovanni Stefano Ugolini
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Laura-Hezner-Weg 7, 8093 Zurich, Switzerland.
| | - Miaoxiao Wang
- Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
- Department of Environmental Microbiology, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Duebendorf, Switzerland
| | - Eleonora Secchi
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Laura-Hezner-Weg 7, 8093 Zurich, Switzerland.
| | - Roberto Pioli
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Laura-Hezner-Weg 7, 8093 Zurich, Switzerland.
| | - Martin Ackermann
- Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
- Department of Environmental Microbiology, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Duebendorf, Switzerland
- Laboratory of Microbial Systems Ecology, School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédéral de Lausanne (EPFL), Lausanne, Switzerland
| | - Roman Stocker
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Laura-Hezner-Weg 7, 8093 Zurich, Switzerland.
| |
Collapse
|
12
|
Phan TV, Mattingly HH, Vo L, Marvin JS, Looger LL, Emonet T. Direct measurement of dynamic attractant gradients reveals breakdown of the Patlak-Keller-Segel chemotaxis model. Proc Natl Acad Sci U S A 2024; 121:e2309251121. [PMID: 38194458 PMCID: PMC10801886 DOI: 10.1073/pnas.2309251121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 12/07/2023] [Indexed: 01/11/2024] Open
Abstract
Chemotactic bacteria not only navigate chemical gradients, but also shape their environments by consuming and secreting attractants. Investigating how these processes influence the dynamics of bacterial populations has been challenging because of a lack of experimental methods for measuring spatial profiles of chemoattractants in real time. Here, we use a fluorescent sensor for aspartate to directly measure bacterially generated chemoattractant gradients during collective migration. Our measurements show that the standard Patlak-Keller-Segel model for collective chemotactic bacterial migration breaks down at high cell densities. To address this, we propose modifications to the model that consider the impact of cell density on bacterial chemotaxis and attractant consumption. With these changes, the model explains our experimental data across all cell densities, offering insight into chemotactic dynamics. Our findings highlight the significance of considering cell density effects on bacterial behavior, and the potential for fluorescent metabolite sensors to shed light on the complex emergent dynamics of bacterial communities.
Collapse
Affiliation(s)
- Trung V. Phan
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT06511
- Quantitative Biology Institute, Yale University, New Haven, CT06511
| | | | - Lam Vo
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT06511
- Quantitative Biology Institute, Yale University, New Haven, CT06511
| | - Jonathan S. Marvin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA20147
| | - Loren L. Looger
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA20147
- HHMI, University of California, San Diego, CA92093
- Department of Neurosciences, University of California, San Diego, CA92093
| | - Thierry Emonet
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT06511
- Quantitative Biology Institute, Yale University, New Haven, CT06511
- Department of Physics, Yale University, New Haven, CT06511
| |
Collapse
|
13
|
Moreno R, Rojo F. What are the signals that control catabolite repression in Pseudomonas? Microb Biotechnol 2024; 17:e14407. [PMID: 38227132 PMCID: PMC10832556 DOI: 10.1111/1751-7915.14407] [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: 11/17/2023] [Revised: 12/29/2023] [Accepted: 01/02/2024] [Indexed: 01/17/2024] Open
Abstract
Metabolically versatile bacteria exhibit a global regulatory response known as carbon catabolite repression (CCR), which prioritizes some carbon sources over others when all are present in sufficient amounts. This optimizes growth by distributing metabolite fluxes, but can restrict yields in biotechnological applications. The molecular mechanisms and preferred substrates for CCR vary between bacterial groups. Escherichia coli prioritizes glucose whereas Pseudomonas sp. prefer certain organic acids or amino acids. A significant issue in understanding (and potentially bypassing) CCR is the lack of information about the signals that trigger this regulatory response. In E. coli, several key compounds act as flux sensors, governing the flow of metabolites through catabolic pathways and preventing imbalances. These flux sensors can also modulate the CCR response. It has been suggested that the order of substrate preference is determined by carbon uptake flux rather than substrate identity. For Pseudomonas, much less information is available, as the signals that induce CCR are poorly understood. This article briefly discusses the available evidence on the signals that trigger CCR and the questions that remain to be answered in Pseudomonas.
Collapse
Affiliation(s)
- Renata Moreno
- Department of Microbial BiotechnologyCentro Nacional de Biotecnología, CSICMadridSpain
| | - Fernando Rojo
- Department of Microbial BiotechnologyCentro Nacional de Biotecnología, CSICMadridSpain
| |
Collapse
|
14
|
Wang T, Li L, Figeys D, Liu YY. Pairing metagenomics and metaproteomics to characterize ecological niches and metabolic essentiality of gut microbiomes. ISME COMMUNICATIONS 2024; 4:ycae063. [PMID: 38808120 PMCID: PMC11131966 DOI: 10.1093/ismeco/ycae063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/15/2024] [Accepted: 04/26/2024] [Indexed: 05/30/2024]
Abstract
The genome of a microorganism encodes its potential functions that can be implemented through expressed proteins. It remains elusive how a protein's selective expression depends on its metabolic essentiality to microbial growth or its ability to claim resources as ecological niches. To reveal a protein's metabolic or ecological role, we developed a computational pipeline, which pairs metagenomics and metaproteomics data to quantify each protein's gene-level and protein-level functional redundancy simultaneously. We first illustrated the idea behind the pipeline using simulated data of a consumer-resource model. We then validated it using real data from human and mouse gut microbiome samples. In particular, we analyzed ABC-type transporters and ribosomal proteins, confirming that the metabolic and ecological roles predicted by our pipeline agree well with prior knowledge. Finally, we performed in vitro cultures of a human gut microbiome sample and investigated how oversupplying various sugars involved in ecological niches influences the community structure and protein abundance. The presented results demonstrate the performance of our pipeline in identifying proteins' metabolic and ecological roles, as well as its potential to help us design nutrient interventions to modulate the human microbiome.
Collapse
Affiliation(s)
- Tong Wang
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, United States
| | - Leyuan Li
- State Key Laboratory of Medical Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing 102206, China
- School of Pharmaceutical Sciences and Ottawa Institute of Systems Biology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H8M5, Canada
| | - Daniel Figeys
- School of Pharmaceutical Sciences and Ottawa Institute of Systems Biology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H8M5, Canada
| | - Yang-Yu Liu
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, United States
- Center for Artificial Intelligence and Modeling, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL 61820, United States
| |
Collapse
|
15
|
Mukherjee A, Chang YF, Huang Y, Benites NC, Ammar L, Ealy J, Polk M, Basan M. Plasticity of growth laws tunes resource allocation strategies in bacteria. PLoS Comput Biol 2024; 20:e1011735. [PMID: 38190385 PMCID: PMC10798636 DOI: 10.1371/journal.pcbi.1011735] [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: 08/04/2023] [Revised: 01/19/2024] [Accepted: 12/04/2023] [Indexed: 01/10/2024] Open
Abstract
Bacteria like E. coli grow at vastly different rates on different substrates, however, the precise reason for this variability is poorly understood. Different growth rates have been attributed to 'nutrient quality', a key parameter in bacterial growth laws. However, it remains unclear to what extent nutrient quality is rooted in fundamental biochemical constraints like the energy content of nutrients, the protein cost required for their uptake and catabolism, or the capacity of the plasma membrane for nutrient transporters. Here, we show that while nutrient quality is indeed reflected in protein investment in substrate-specific transporters and enzymes, this is not a fundamental limitation on growth rate, at least for certain 'poor' substrates. We show that it is possible to turn mannose, one of the 'poorest' substrates of E. coli, into one of the 'best' substrates by reengineering chromosomal promoters of the mannose transporter and metabolic enzymes required for mannose degradation. This result falls in line with previous observations of more subtle growth rate improvement for many other carbon sources. However, we show that this faster growth rate comes at the cost of diverse cellular capabilities, reflected in longer lag phases, worse starvation survival and lower motility. We show that addition of cAMP to the medium can rescue these phenotypes but imposes a corresponding growth cost. Based on these data, we propose that nutrient quality is largely a self-determined, plastic property that can be modulated by the fraction of proteomic resources devoted to a specific substrate in the much larger proteome sector of catabolically activated genes. Rather than a fundamental biochemical limitation, nutrient quality reflects resource allocation decisions that are shaped by evolution in specific ecological niches and can be quickly adapted if necessary.
Collapse
Affiliation(s)
- Avik Mukherjee
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Yu-Fang Chang
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Yanqing Huang
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Nina Catherine Benites
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Leander Ammar
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jade Ealy
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mark Polk
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Markus Basan
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| |
Collapse
|
16
|
Bren A, Glass DS, Kohanim YK, Mayo A, Alon U. Tradeoffs in bacterial physiology determine the efficiency of antibiotic killing. Proc Natl Acad Sci U S A 2023; 120:e2312651120. [PMID: 38096408 PMCID: PMC10742385 DOI: 10.1073/pnas.2312651120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 11/02/2023] [Indexed: 12/18/2023] Open
Abstract
Antibiotic effectiveness depends on a variety of factors. While many mechanistic details of antibiotic action are known, the connection between death rate and bacterial physiology is poorly understood. A common observation is that death rate in antibiotics rises linearly with growth rate; however, it remains unclear how other factors, such as environmental conditions and whole-cell physiological properties, affect bactericidal activity. To address this, we developed a high-throughput assay to precisely measure antibiotic-mediated death. We found that death rate is linear in growth rate, but the slope depends on environmental conditions. Growth under stress lowers death rate compared to nonstressed environments with similar growth rate. To understand stress's role, we developed a mathematical model of bacterial death based on resource allocation that includes a stress-response sector; we identify this sector using RNA-seq. Our model accurately predicts the minimal inhibitory concentration (MIC) with zero free parameters across a wide range of growth conditions. The model also quantitatively predicts death and MIC when sectors are experimentally modulated using cyclic adenosine monophosphate (cAMP), including protection from death at very low cAMP levels. The present study shows that different conditions with equal growth rate can have different death rates and establishes a quantitative relation between growth, death, and MIC that suggests approaches to improve antibiotic efficacy.
Collapse
Affiliation(s)
- Anat Bren
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot7610001, Israel
| | - David S. Glass
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot7610001, Israel
| | - Yael Korem Kohanim
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT06520
| | - Avi Mayo
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot7610001, Israel
| | - Uri Alon
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot7610001, Israel
| |
Collapse
|
17
|
Nguyen V, Xue P, Li Y, Zhao H, Lu T. Controlling circuitry underlies the growth optimization of Saccharomyces cerevisiae. Metab Eng 2023; 80:173-183. [PMID: 37739159 PMCID: PMC11089650 DOI: 10.1016/j.ymben.2023.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 08/29/2023] [Accepted: 09/19/2023] [Indexed: 09/24/2023]
Abstract
Microbial growth emerges from coordinated synthesis of various cellular components from limited resources. In Saccharomyces cerevisiae, cyclic AMP (cAMP)-mediated signaling is shown to orchestrate cellular metabolism; however, it remains unclear quantitatively how the controlling circuit drives resource partition and subsequently shapes biomass growth. Here we combined experiment with mathematical modeling to dissect the signaling-mediated growth optimization of S. cerevisiae. We showed that, through cAMP-mediated control, the organism achieves maximal or nearly maximal steady-state growth during the utilization of multiple tested substrates as well as under perturbations impairing glucose uptake. However, the optimal cAMP concentration varies across cases, suggesting that different modes of resource allocation are adopted for varied conditions. Under settings with nutrient alterations, S. cerevisiae tunes its cAMP level to dynamically reprogram itself to realize rapid adaptation. Moreover, to achieve growth maximization, cells employ additional regulatory systems such as the GCN2-mediated amino acid control. This study establishes a systematic understanding of global resource allocation in S. cerevisiae, providing insights into quantitative yeast physiology as well as metabolic strain engineering for biotechnological applications.
Collapse
Affiliation(s)
- Viviana Nguyen
- Department of Physics, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Pu Xue
- Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; Carl R Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Yifei Li
- Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Huimin Zhao
- Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; Carl R Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.
| | - Ting Lu
- Department of Physics, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; Carl R Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA; National Center for Supercomputing Applications, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.
| |
Collapse
|
18
|
Wehrens M, Krah LHJ, Towbin BD, Hermsen R, Tans SJ. The interplay between metabolic stochasticity and cAMP-CRP regulation in single E. coli cells. Cell Rep 2023; 42:113284. [PMID: 37864793 DOI: 10.1016/j.celrep.2023.113284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 07/17/2023] [Accepted: 09/29/2023] [Indexed: 10/23/2023] Open
Abstract
The inherent stochasticity of metabolism raises a critical question for understanding homeostasis: are cellular processes regulated in response to internal fluctuations? Here, we show that, in E. coli cells under constant external conditions, catabolic enzyme expression continuously responds to metabolic fluctuations. The underlying regulatory feedback is enabled by the cyclic AMP (cAMP) and cAMP receptor protein (CRP) system, which controls catabolic enzyme expression based on metabolite concentrations. Using single-cell microscopy, genetic constructs in which this feedback is disabled, and mathematical modeling, we show how fluctuations circulate through the metabolic and genetic network at sub-cell-cycle timescales. Modeling identifies four noise propagation modes, including one specific to CRP regulation. Together, these modes correctly predict noise circulation at perturbed cAMP levels. The cAMP-CRP system may thus have evolved to control internal metabolic fluctuations in addition to external growth conditions. We conjecture that second messengers may more broadly function to achieve cellular homeostasis.
Collapse
Affiliation(s)
- Martijn Wehrens
- AMOLF, 1098 XG Amsterdam, the Netherlands; Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and University Medical Center, 3584 CT Utrecht, the Netherlands
| | - Laurens H J Krah
- Theoretical Biology Group, Biology Department, Utrecht University, 3584 CH Utrecht, the Netherlands; Centre for Complex Systems Studies, Utrecht University, 3584 CE Utrecht, the Netherlands
| | - Benjamin D Towbin
- Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland
| | - Rutger Hermsen
- Theoretical Biology Group, Biology Department, Utrecht University, 3584 CH Utrecht, the Netherlands; Centre for Complex Systems Studies, Utrecht University, 3584 CE Utrecht, the Netherlands
| | - Sander J Tans
- AMOLF, 1098 XG Amsterdam, the Netherlands; Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ Delft, the Netherlands.
| |
Collapse
|
19
|
Hu XP, Schroeder S, Lercher MJ. Proteome efficiency of metabolic pathways in Escherichia coli increases along the nutrient flow. mSystems 2023; 8:e0076023. [PMID: 37795991 PMCID: PMC10654084 DOI: 10.1128/msystems.00760-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 08/24/2023] [Indexed: 10/06/2023] Open
Abstract
IMPORTANCE Protein translation is the most expensive cellular process in fast-growing bacteria, and efficient proteome usage should thus be under strong natural selection. However, recent studies show that a considerable part of the proteome is unneeded for instantaneous cell growth in Escherichia coli. We still lack a systematic understanding of how this excess proteome is distributed across different pathways as a function of the growth conditions. We estimated the minimal required proteome across growth conditions in E. coli and compared the predictions with experimental data. We found that the proteome allocated to the most expensive internal pathways, including translation and the synthesis of amino acids and cofactors, is near the minimally required levels. In contrast, transporters and central carbon metabolism show much higher proteome levels than the predicted minimal abundance. Our analyses show that the proteome fraction unneeded for instantaneous cell growth decreases along the nutrient flow in E. coli.
Collapse
Affiliation(s)
- Xiao-Pan Hu
- Institute for Computer Science, Heinrich Heine University, Düsseldorf, Germany
- Department of Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Stefan Schroeder
- Institute for Computer Science, Heinrich Heine University, Düsseldorf, Germany
- Department of Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Martin J. Lercher
- Institute for Computer Science, Heinrich Heine University, Düsseldorf, Germany
- Department of Biology, Heinrich Heine University, Düsseldorf, Germany
| |
Collapse
|
20
|
Lyu Z, Villanueva P, O’Malley L, Murphy P, Augenstreich J, Briken V, Singh A, Ling J. Genome-wide screening reveals metabolic regulation of stop-codon readthrough by cyclic AMP. Nucleic Acids Res 2023; 51:9905-9919. [PMID: 37670559 PMCID: PMC10570021 DOI: 10.1093/nar/gkad725] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/12/2023] [Accepted: 08/21/2023] [Indexed: 09/07/2023] Open
Abstract
Translational fidelity is critical for microbial fitness, survival and stress responses. Much remains unknown about the genetic and environmental control of translational fidelity and its single-cell heterogeneity. In this study, we used a high-throughput fluorescence-based assay to screen a knock-out library of Escherichia coli and identified over 20 genes critical for stop-codon readthrough. Most of these identified genes were not previously known to affect translational fidelity. Intriguingly, we show that several genes controlling metabolism, including cyaA and crp, enhance stop-codon readthrough. CyaA catalyzes the synthesis of cyclic adenosine monophosphate (cAMP). Combining RNA sequencing, metabolomics and biochemical analyses, we show that deleting cyaA impairs amino acid catabolism and production of ATP, thus repressing the transcription of rRNAs and tRNAs to decrease readthrough. Single-cell analyses further show that cAMP is a major driver of heterogeneity in stop-codon readthrough and rRNA expression. Our results highlight that carbon metabolism is tightly coupled with stop-codon readthrough.
Collapse
Affiliation(s)
- Zhihui Lyu
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Patricia Villanueva
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Liam O’Malley
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Parker Murphy
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Jacques Augenstreich
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Volker Briken
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering and Biomedical Engineering, University of Delaware, Newark, DE, USA
| | - Jiqiang Ling
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD, USA
| |
Collapse
|
21
|
Zhu M, Wang Q, Mu H, Han F, Wang Y, Dai X. A fitness trade-off between growth and survival governed by Spo0A-mediated proteome allocation constraints in Bacillus subtilis. SCIENCE ADVANCES 2023; 9:eadg9733. [PMID: 37756393 PMCID: PMC10530083 DOI: 10.1126/sciadv.adg9733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 08/25/2023] [Indexed: 09/29/2023]
Abstract
Growth and survival are key determinants of bacterial fitness. However, how resource allocation of bacteria could reconcile these two traits to maximize fitness remains poorly understood. Here, we find that the resource allocation strategy of Bacillus subtilis does not lead to growth maximization on various carbon sources. Survival-related pathways impose strong proteome constraints on B. subtilis. Knockout of a master regulator gene, spo0A, triggers a global resource reallocation from survival-related pathways to biosynthesis pathways, further strongly stimulating the growth of B. subtilis. However, the fitness of spo0A-null strain is severely compromised because of various disadvantageous phenotypes (e.g., abolished sporulation and enhanced cell lysis). In particular, it also exhibits a strong defect in peptide utilization, being unable to efficiently recycle nutrients from the lysed cell debris to maintain long-term viability. Our work uncovers a fitness trade-off between growth and survival that governed by Spo0A-mediated proteome allocation constraints in B. subtilis, further shedding light on the fundamental design principle of bacteria.
Collapse
Affiliation(s)
| | | | | | - Fei Han
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei province, China
| | - Yanling Wang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei province, China
| | | |
Collapse
|
22
|
Pokorzynski ND, Groisman EA. How Bacterial Pathogens Coordinate Appetite with Virulence. Microbiol Mol Biol Rev 2023; 87:e0019822. [PMID: 37358444 PMCID: PMC10521370 DOI: 10.1128/mmbr.00198-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2023] Open
Abstract
Cells adjust growth and metabolism to nutrient availability. Having access to a variety of carbon sources during infection of their animal hosts, facultative intracellular pathogens must efficiently prioritize carbon utilization. Here, we discuss how carbon source controls bacterial virulence, with an emphasis on Salmonella enterica serovar Typhimurium, which causes gastroenteritis in immunocompetent humans and a typhoid-like disease in mice, and propose that virulence factors can regulate carbon source prioritization by modifying cellular physiology. On the one hand, bacterial regulators of carbon metabolism control virulence programs, indicating that pathogenic traits appear in response to carbon source availability. On the other hand, signals controlling virulence regulators may impact carbon source utilization, suggesting that stimuli that bacterial pathogens experience within the host can directly impinge on carbon source prioritization. In addition, pathogen-triggered intestinal inflammation can disrupt the gut microbiota and thus the availability of carbon sources. By coordinating virulence factors with carbon utilization determinants, pathogens adopt metabolic pathways that may not be the most energy efficient because such pathways promote resistance to antimicrobial agents and also because host-imposed deprivation of specific nutrients may hinder the operation of certain pathways. We propose that metabolic prioritization by bacteria underlies the pathogenic outcome of an infection.
Collapse
Affiliation(s)
- Nick D. Pokorzynski
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Eduardo A. Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
- Yale Microbial Sciences Institute, West Haven, Connecticut, USA
| |
Collapse
|
23
|
Mukherjee A, Chang YF, Huang Y, Ealy J, Polk M, Basan M. Plasticity of growth laws tunes resource allocation strategies in bacteria. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.22.554312. [PMID: 37662352 PMCID: PMC10473609 DOI: 10.1101/2023.08.22.554312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Bacteria like E. coli grow at vastly different rates on different substrates, however, the precise reason for this variability is poorly understood. Different growth rates have been attributed to 'nutrient quality', a key parameter in bacterial growth laws. However, it remains unclear to what extent nutrient quality is rooted in fundamental biochemical constraints like the energy content of nutrients, the protein cost required for their uptake and catabolism, or the capacity of the plasma membrane for nutrient transporters. Here, we show that while nutrient quality is indeed reflected in protein investment in substrate-specific transporters and enzymes, this is not a fundamental limitation on growth rate. We show that it is possible to turn mannose, one of the 'poorest' substrates of E. coli, into one of the 'best' substrates by reengineering chromosomal promoters of the mannose transporter and metabolic enzymes required for mannose degradation. However, we show that this faster growth rate comes at the cost of diverse cellular capabilities, reflected in longer lag phases, worse starvation survival and lower motility. We show that addition of cAMP to the medium can rescue these phenotypes but imposes a corresponding growth cost. Based on these data, we propose that nutrient quality is largely a self-determined, plastic property that can be modulated by the fraction of proteomic resources devoted to a specific substrate in the much larger proteome sector of catabolically activated genes. Rather than a fundamental biochemical limitation, nutrient quality reflects resource allocation decisions that are shaped by evolution in specific ecological niches and can be quickly adapted if necessary.
Collapse
|
24
|
Zhu J, Chu P, Fu X. Unbalanced response to growth variations reshapes the cell fate decision landscape. Nat Chem Biol 2023; 19:1097-1104. [PMID: 36959461 DOI: 10.1038/s41589-023-01302-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 02/27/2023] [Indexed: 03/25/2023]
Abstract
The global regulation of cell growth rate on gene expression perturbs the performance of gene networks, which would impose complex variations on the cell-fate decision landscape. Here we use a simple synthetic circuit of mutual repression that allows a bistable landscape to examine how such global regulation would affect the stability of phenotypic landscape and the accompanying dynamics of cell-fate determination. We show that the landscape experiences a growth-rate-induced bifurcation between monostability and bistability. Theoretical and experimental analyses reveal that this bifurcating deformation of landscape arises from the unbalanced response of gene expression to growth variations. The path of growth transition across the bifurcation would reshape cell-fate decisions. These results demonstrate the importance of growth regulation on cell-fate determination processes, regardless of specific molecular signaling or regulation.
Collapse
Affiliation(s)
- Jingwen Zhu
- CAS Key Laboratory for Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Pan Chu
- CAS Key Laboratory for Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiongfei Fu
- CAS Key Laboratory for Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
- University of Chinese Academy of Sciences, Beijing, China.
| |
Collapse
|
25
|
Kleijn IT, Marguerat S, Shahrezaei V. A coarse-grained resource allocation model of carbon and nitrogen metabolism in unicellular microbes. J R Soc Interface 2023; 20:20230206. [PMID: 37751876 PMCID: PMC10522411 DOI: 10.1098/rsif.2023.0206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 09/08/2023] [Indexed: 09/28/2023] Open
Abstract
Coarse-grained resource allocation models (C-GRAMs) are simple mathematical models of cell physiology, where large components of the macromolecular composition are abstracted into single entities. The dynamics and steady-state behaviour of such models provides insights on optimal allocation of cellular resources and have explained experimentally observed cellular growth laws, but current models do not account for the uptake of compound sources of carbon and nitrogen. Here, we formulate a C-GRAM with nitrogen and carbon pathways converging on biomass production, with parametrizations accounting for respirofermentative and purely respiratory growth. The model describes the effects of the uptake of sugars, ammonium and/or compound nutrients such as amino acids on the translational resource allocation towards proteome sectors that maximized the growth rate. It robustly recovers cellular growth laws including the Monod law and the ribosomal growth law. Furthermore, we show how the growth-maximizing balance between carbon uptake, recycling, and excretion depends on the nutrient environment. Lastly, we find a robust linear correlation between the ribosome fraction and the abundance of amino acid equivalents in the optimal cell, which supports the view that simple regulation of translational gene expression can enable cells to achieve an approximately optimal growth state.
Collapse
Affiliation(s)
- Istvan T. Kleijn
- Department of Mathematics, Faculty of Natural Sciences, Imperial College London, London, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
- MRC London Institute of Medical Sciences, London, UK
- Division of Breast Cancer Research, The Institute of Cancer Research, London, UK
- Ralph Lauren Centre for Breast Cancer Research, The Royal Marsden NHS Foundation Trust, London, UK
| | - Samuel Marguerat
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK
- MRC London Institute of Medical Sciences, London, UK
| | - Vahid Shahrezaei
- Department of Mathematics, Faculty of Natural Sciences, Imperial College London, London, UK
| |
Collapse
|
26
|
Guessous G, Patsalo V, Balakrishnan R, Çağlar T, Williamson JR, Hwa T. Inherited chitinases enable sustained growth and rapid dispersal of bacteria from chitin particles. Nat Microbiol 2023; 8:1695-1705. [PMID: 37580592 DOI: 10.1038/s41564-023-01444-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 07/04/2023] [Indexed: 08/16/2023]
Abstract
Many biogeochemical functions involve bacteria utilizing solid substrates. However, little is known about the coordination of bacterial growth with the kinetics of attachment to and detachment from such substrates. In this quantitative study of Vibrio sp. 1A01 growing on chitin particles, we reveal the heterogeneous nature of the exponentially growing culture comprising two co-existing subpopulations: a minority replicating on chitin particles and a non-replicating majority which was planktonic. This partition resulted from a high rate of cell detachment from particles. Despite high detachment, sustained exponential growth of cells on particles was enabled by the enrichment of extracellular chitinases excreted and left behind by detached cells. The 'inheritance' of these chitinases sustains the colonizing subpopulation despite its reduced density. This simple mechanism helps to circumvent a trade-off between growth and dispersal, allowing particle-associated marine heterotrophs to explore new habitats without compromising their fitness on the habitat they have already colonized.
Collapse
Affiliation(s)
- Ghita Guessous
- Department of Physics, University of California at San Diego, La Jolla, CA, USA
| | - Vadim Patsalo
- Department of Integrative Structural and Computational Biology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA
- DataBricks, San Diego, CA, USA
| | - Rohan Balakrishnan
- Department of Physics, University of California at San Diego, La Jolla, CA, USA
| | - Tolga Çağlar
- Department of Physics, University of California at San Diego, La Jolla, CA, USA
- San Diego Supercomputer Center, La Jolla, CA, USA
| | - James R Williamson
- Department of Integrative Structural and Computational Biology, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Terence Hwa
- Department of Physics, University of California at San Diego, La Jolla, CA, USA.
| |
Collapse
|
27
|
Bate F, Amekan Y, Pushkin DO, Chong JPJ, Bees M. Emergent Lag Phase in Flux-Regulation Models of Bacterial Growth. Bull Math Biol 2023; 85:84. [PMID: 37580520 PMCID: PMC10425510 DOI: 10.1007/s11538-023-01189-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 07/21/2023] [Indexed: 08/16/2023]
Abstract
Lag phase is observed in bacterial growth during a sudden change in conditions: growth is inhibited whilst cells adapt to the environment. Bi-phasic, or diauxic growth is commonly exhibited by many species. In the presence of two sugars, cells initially grow by consuming the preferred sugar then undergo a lag phase before resuming growth on the second. Biomass increase is characterised by a diauxic growth curve: exponential growth followed by a period of no growth before a second exponential growth. Recent literature lacks a complete dynamic description, artificially modelling lag phase and employing non-physical representations of precursor pools. Here, we formulate a rational mechanistic model based on flux-regulation/proteome partitioning with a finite precursor pool that reveals core mechanisms in a compact form. Unlike earlier systems, the characteristic dynamics emerge as part of the solution, including the lag phase. Focussing on growth of Escherichia coli on a glucose-lactose mixture we show results accurately reproduce experiments. We show that for a single strain of E. coli, diauxic growth leads to optimised biomass yields. However, intriguingly, for two competing strains diauxic growth is not always the best strategy. Our description can be generalised to model multiple different microorganisms and investigate competition between species/strains.
Collapse
Affiliation(s)
- Fiona Bate
- Department of Mathematics, University of York, York, YO10 5DD UK
| | | | | | | | - Martin Bees
- Department of Mathematics, University of York, York, YO10 5DD UK
| |
Collapse
|
28
|
Weith M, Großbach J, Clement‐Ziza M, Gillet L, Rodríguez‐López M, Marguerat S, Workman CT, Picotti P, Bähler J, Aebersold R, Beyer A. Genetic effects on molecular network states explain complex traits. Mol Syst Biol 2023; 19:e11493. [PMID: 37485750 PMCID: PMC10407735 DOI: 10.15252/msb.202211493] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 06/29/2023] [Accepted: 07/04/2023] [Indexed: 07/25/2023] Open
Abstract
The complexity of many cellular and organismal traits results from the integration of genetic and environmental factors via molecular networks. Network structure and effect propagation are best understood at the level of functional modules, but so far, no concept has been established to include the global network state. Here, we show when and how genetic perturbations lead to molecular changes that are confined to small parts of a network versus when they lead to modulation of network states. Integrating multi-omics profiling of genetically heterogeneous budding and fission yeast strains with an array of cellular traits identified a central state transition of the yeast molecular network that is related to PKA and TOR (PT) signaling. Genetic variants affecting this PT state globally shifted the molecular network along a single-dimensional axis, thereby modulating processes including energy and amino acid metabolism, transcription, translation, cell cycle control, and cellular stress response. We propose that genetic effects can propagate through large parts of molecular networks because of the functional requirement to centrally coordinate the activity of fundamental cellular processes.
Collapse
Affiliation(s)
- Matthias Weith
- Excellence Cluster on Cellular Stress Responses in Aging Associated DiseasesUniversity of CologneCologneGermany
| | - Jan Großbach
- Excellence Cluster on Cellular Stress Responses in Aging Associated DiseasesUniversity of CologneCologneGermany
| | | | - Ludovic Gillet
- Department of BiologyInstitute of Molecular Systems Biology, ETH ZürichZürichSwitzerland
| | - María Rodríguez‐López
- Institute of Healthy Ageing and Department of Genetics, Evolution & EnvironmentUniversity College LondonLondonUK
| | - Samuel Marguerat
- Institute of Healthy Ageing and Department of Genetics, Evolution & EnvironmentUniversity College LondonLondonUK
| | - Christopher T Workman
- Department of Biotechnology and BiomedicineTechnical University of DenmarkLyngbyDenmark
| | - Paola Picotti
- Department of BiologyInstitute of Molecular Systems Biology, ETH ZürichZürichSwitzerland
| | - Jürg Bähler
- Institute of Healthy Ageing and Department of Genetics, Evolution & EnvironmentUniversity College LondonLondonUK
| | - Ruedi Aebersold
- Department of BiologyInstitute of Molecular Systems Biology, ETH ZürichZürichSwitzerland
| | - Andreas Beyer
- Excellence Cluster on Cellular Stress Responses in Aging Associated DiseasesUniversity of CologneCologneGermany
| |
Collapse
|
29
|
Mori M, Cheng C, Taylor BR, Okano H, Hwa T. Functional decomposition of metabolism allows a system-level quantification of fluxes and protein allocation towards specific metabolic functions. Nat Commun 2023; 14:4161. [PMID: 37443156 PMCID: PMC10345195 DOI: 10.1038/s41467-023-39724-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
Quantifying the contribution of individual molecular components to complex cellular processes is a grand challenge in systems biology. Here we establish a general theoretical framework (Functional Decomposition of Metabolism, FDM) to quantify the contribution of every metabolic reaction to metabolic functions, e.g. the synthesis of biomass building blocks. FDM allowed for a detailed quantification of the energy and biosynthesis budget for growing Escherichia coli cells. Surprisingly, the ATP generated during the biosynthesis of building blocks from glucose almost balances the demand from protein synthesis, the largest energy expenditure known for growing cells. This leaves the bulk of the energy generated by fermentation and respiration unaccounted for, thus challenging the common notion that energy is a key growth-limiting resource. Moreover, FDM together with proteomics enables the quantification of enzymes contributing towards each metabolic function, allowing for a first-principle formulation of a coarse-grained model of global protein allocation based on the structure of the metabolic network.
Collapse
Affiliation(s)
- Matteo Mori
- Department of Physics, University of California San Diego, 9500 Gilman Dr. La Jolla, San Diego, CA, 92093, USA.
| | - Chuankai Cheng
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Brian R Taylor
- Department of Physics, University of California San Diego, 9500 Gilman Dr. La Jolla, San Diego, CA, 92093, USA
| | - Hiroyuki Okano
- Department of Physics, University of California San Diego, 9500 Gilman Dr. La Jolla, San Diego, CA, 92093, USA
| | - Terence Hwa
- Department of Physics, University of California San Diego, 9500 Gilman Dr. La Jolla, San Diego, CA, 92093, USA
| |
Collapse
|
30
|
Ji X, Lin J. Implications of differential size-scaling of cell-cycle regulators on cell size homeostasis. PLoS Comput Biol 2023; 19:e1011336. [PMID: 37506170 PMCID: PMC10411824 DOI: 10.1371/journal.pcbi.1011336] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 08/09/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023] Open
Abstract
Accurate timing of division and size homeostasis is crucial for cells. A potential mechanism for cells to decide the timing of division is the differential scaling of regulatory protein copy numbers with cell size. However, it remains unclear whether such a mechanism can lead to robust growth and division, and how the scaling behaviors of regulatory proteins influence the cell size distribution. Here we study a mathematical model combining gene expression and cell growth, in which the cell-cycle activators scale superlinearly with cell size while the inhibitors scale sublinearly. The cell divides once the ratio of their concentrations reaches a threshold value. We find that the cell can robustly grow and divide within a finite range of the threshold value with the cell size proportional to the ploidy. In a stochastic version of the model, the cell size at division is uncorrelated with that at birth. Also, the more differential the cell-size scaling of the cell-cycle regulators is, the narrower the cell-size distribution is. Intriguingly, our model with multiple regulators rationalizes the observation that after the deletion of a single regulator, the coefficient of variation of cell size remains roughly the same though the average cell size changes significantly. Our work reveals that the differential scaling of cell-cycle regulators provides a robust mechanism of cell size control.
Collapse
Affiliation(s)
- Xiangrui Ji
- Yuanpei College, Peking University, Beijing, China
| | - Jie Lin
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| |
Collapse
|
31
|
Hou C, Liu L, Ju X, Xiao Y, Li B, You C. Revisiting Fur Regulon Leads to a Comprehensive Understanding of Iron and Fur Regulation. Int J Mol Sci 2023; 24:ijms24109078. [PMID: 37240425 DOI: 10.3390/ijms24109078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/16/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
Iron is an essential element because it functions as a cofactor of many enzymes, but excess iron causes cell damage. Iron hemostasis in Escherichia coli was transcriptionally maintained by the ferric uptake regulator (Fur). Despite having been studied extensively, the comprehensive physiological roles and mechanisms of Fur-coordinated iron metabolism still remain obscure. In this work, by integrating a high-resolution transcriptomic study of the Fur wild-type and knockout Escherichia coli K-12 strains in the presence or absence of iron with high-throughput ChIP-seq assay and physiological studies, we revisited the regulatory roles of iron and Fur systematically and discovered several intriguing features of Fur regulation. The size of the Fur regulon was expanded greatly, and significant discrepancies were observed to exist between the regulations of Fur on the genes under its direct repression and activation. Fur showed stronger binding strength to the genes under its repression, and genes that were repressed by Fur were more sensitive to Fur and iron regulation as compared to the genes that were activated by Fur. Finally, we found that Fur linked iron metabolism to many essential processes, and the systemic regulations of Fur on carbon metabolism, respiration, and motility were further validated or discussed. These results highlight how Fur and Fur-controlled iron metabolism affect many cellular processes in a systematic way.
Collapse
Affiliation(s)
- Chaofan Hou
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanology, Shenzhen University, Shenzhen 518055, China
| | - Lin Liu
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanology, Shenzhen University, Shenzhen 518055, China
| | - Xian Ju
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanology, Shenzhen University, Shenzhen 518055, China
| | - Yunzhu Xiao
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanology, Shenzhen University, Shenzhen 518055, China
| | - Bingyu Li
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanology, Shenzhen University, Shenzhen 518055, China
| | - Conghui You
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanology, Shenzhen University, Shenzhen 518055, China
| |
Collapse
|
32
|
Le Y, Lou X, Yu C, Guo C, He Y, Lu Y, Yang H. Integrated metabolomics analysis of Lactobacillus in fermented milk with fish gelatin hydrolysate in different degrees of hydrolysis. Food Chem 2023; 408:135232. [PMID: 36566542 DOI: 10.1016/j.foodchem.2022.135232] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Dual-platform metabolomics combined with multivariate data analysis was used to investigate the effects of adding fish gelatin (FGH) at different degrees of hydrolysis (DH) on the growth and metabolic pathways of different species of Lactobacillus in fermented milk. The results showed that the promotion effect of FGH on Lactobacillus was related to the species of probiotics. The corresponding metabolic pathways also changed, with the promotion of Lactobacillus by FGH mainly regulated through amino acid metabolism, lipid metabolism, and nucleotide metabolism pathways. The excess DH inhibited the growth of L. paracasei by adjusting its metabolic state through reducing nucleotide requirements, allocating protein resources, and adopting a stress response. In conclusion, this study revealed the effectiveness of dual-platform metabolomics in explaining the metabolic mechanisms of probiotics, providing theoretical support and a scientific basis for the development of functional fermented foods.
Collapse
Affiliation(s)
- Yi Le
- Department of Food Science and Technology, National University of Singapore, 117542, Singapore
| | - Xiaowei Lou
- Department of Food Science and Technology, National University of Singapore, 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, China
| | - Chengwei Yu
- Department of Food Science and Technology, National University of Singapore, 117542, Singapore; School of Health, Jiangxi Normal University, Nanchang, Jiangxi 330022, China
| | - Chenxi Guo
- Department of Food Science and Technology, National University of Singapore, 117542, Singapore
| | - Yun He
- Department of Food Science and Technology, National University of Singapore, 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, China
| | - Yuyun Lu
- Department of Food Science and Technology, National University of Singapore, 117542, Singapore
| | - Hongshun Yang
- Department of Food Science and Technology, National University of Singapore, 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou, Jiangsu 215123, China.
| |
Collapse
|
33
|
Scott M, Hwa T. Shaping bacterial gene expression by physiological and proteome allocation constraints. Nat Rev Microbiol 2023; 21:327-342. [PMID: 36376406 PMCID: PMC10121745 DOI: 10.1038/s41579-022-00818-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2022] [Indexed: 11/16/2022]
Abstract
Networks of molecular regulators are often the primary objects of focus in the study of gene regulation, with the machinery of protein synthesis tacitly relegated to the background. Shifting focus to the constraints imposed by the allocation of protein synthesis flux reveals surprising ways in which the actions of molecular regulators are shaped by physiological demands. Using carbon catabolite repression as a case study, we describe how physiological constraints are sensed through metabolic fluxes and how flux-controlled regulation gives rise to simple empirical relations between protein levels and the rate of cell growth.
Collapse
Affiliation(s)
- Matthew Scott
- Department of Applied Mathematics, University of Waterloo, Waterloo, ON, Canada.
| | - Terence Hwa
- Department of Physics, University of California at San Diego, La Jolla, CA, USA.
| |
Collapse
|
34
|
Takano S, Takahashi H, Yama Y, Miyazaki R, Furusawa C, Tsuru S. Inference of transcriptome signatures of Escherichia coli in long-term stationary phase. Sci Rep 2023; 13:5647. [PMID: 37024648 PMCID: PMC10079935 DOI: 10.1038/s41598-023-32525-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 03/29/2023] [Indexed: 04/08/2023] Open
Abstract
"Non-growing" is a dominant life form of microorganisms in nature, where available nutrients and resources are limited. In laboratory culture systems, Escherichia coli can survive for years under starvation, denoted as long-term stationary phase, where a small fraction of cells manages to survive by recycling resources released from nonviable cells. Although the physiology by which viable cells in long-term stationary phase adapt to prolonged starvation is of great interest, their genome-wide response has not been fully understood. In this study, we analyzed transcriptional profiles of cells exposed to the supernatant of 30-day long-term stationary phase culture and found that their transcriptome profiles displayed several similar responses to those of cells in the 16-h short-term stationary phase. Nevertheless, our results revealed that cells in long-term stationary phase supernatant exhibit higher expressions of stress-response genes such as phage shock proteins (psp), and lower expressions of growth-related genes such as ribosomal proteins than those in the short-term stationary phase. We confirmed that the mutant lacking the psp operon showed lower survival and growth rate in the long-term stationary phase culture. This study identified transcriptional responses for stress-resistant physiology in the long-term stationary phase environment.
Collapse
Affiliation(s)
- Sotaro Takano
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
- International Center for Materials Nanoarchitectonics (NIMS), Research Center for Macromolecules and Biomaterials, Tsukuba, Japan
| | - Hiromi Takahashi
- Graduate School of Information Science and Technology, Osaka University, Suita, Osaka, Japan
| | - Yoshie Yama
- Graduate School of Information Science and Technology, Osaka University, Suita, Osaka, Japan
| | - Ryo Miyazaki
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
- Computational Bio Big Data Open Innovation Laboratory (CBBD-OIL), AIST, Tokyo, Japan
| | - Chikara Furusawa
- Graduate School of Science, Universal Biology Institute, The University of Tokyo, Tokyo, Japan
- Center for Biosystem Dynamics Research, RIKEN, Kobe, Japan
| | - Saburo Tsuru
- Graduate School of Science, Universal Biology Institute, The University of Tokyo, Tokyo, Japan.
| |
Collapse
|
35
|
Bremer E, Calteau A, Danchin A, Harwood C, Helmann JD, Médigue C, Palsson BO, Sekowska A, Vallenet D, Zuniga A, Zuniga C. A model industrial workhorse:
Bacillus subtilis
strain 168 and its genome after a quarter of a century. Microb Biotechnol 2023; 16:1203-1231. [PMID: 37002859 DOI: 10.1111/1751-7915.14257] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 03/20/2023] [Indexed: 04/04/2023] Open
Abstract
The vast majority of genomic sequences are automatically annotated using various software programs. The accuracy of these annotations depends heavily on the very few manual annotation efforts that combine verified experimental data with genomic sequences from model organisms. Here, we summarize the updated functional annotation of Bacillus subtilis strain 168, a quarter century after its genome sequence was first made public. Since the last such effort 5 years ago, 1168 genetic functions have been updated, allowing the construction of a new metabolic model of this organism of environmental and industrial interest. The emphasis in this review is on new metabolic insights, the role of metals in metabolism and macromolecule biosynthesis, functions involved in biofilm formation, features controlling cell growth, and finally, protein agents that allow class discrimination, thus allowing maintenance management, and accuracy of all cell processes. New 'genomic objects' and an extensive updated literature review have been included for the sequence, now available at the International Nucleotide Sequence Database Collaboration (INSDC: AccNum AL009126.4).
Collapse
Affiliation(s)
- Erhard Bremer
- Department of Biology, Laboratory for Microbiology and Center for Synthetic Microbiology (SYNMIKRO) Philipps‐University Marburg Marburg Germany
| | - Alexandra Calteau
- LABGeM, Génomique Métabolique, CEA, Genoscope, Institut de Biologie François Jacob Université d'Évry, Université Paris‐Saclay, CNRS Évry France
| | - Antoine Danchin
- School of Biomedical Sciences, Li KaShing Faculty of Medicine Hong Kong University Pokfulam SAR Hong Kong China
| | - Colin Harwood
- Centre for Bacterial Cell Biology, Biosciences Institute Newcastle University Baddiley Clark Building Newcastle upon Tyne UK
| | - John D. Helmann
- Department of Microbiology Cornell University Ithaca New York USA
| | - Claudine Médigue
- LABGeM, Génomique Métabolique, CEA, Genoscope, Institut de Biologie François Jacob Université d'Évry, Université Paris‐Saclay, CNRS Évry France
| | - Bernhard O. Palsson
- Department of Bioengineering University of California San Diego La Jolla USA
| | | | - David Vallenet
- LABGeM, Génomique Métabolique, CEA, Genoscope, Institut de Biologie François Jacob Université d'Évry, Université Paris‐Saclay, CNRS Évry France
| | - Abril Zuniga
- Department of Biology San Diego State University San Diego California USA
| | - Cristal Zuniga
- Bioinformatics and Medical Informatics Graduate Program San Diego State University San Diego California USA
| |
Collapse
|
36
|
Park J, Lee SM, Ebrahim A, Scott-Nevros Z, Kim J, Yang L, Sastry A, Seo S, Palsson BO, Kim D. Model-driven experimental design workflow expands understanding of regulatory role of Nac in Escherichia coli. NAR Genom Bioinform 2023; 5:lqad006. [PMID: 36685725 PMCID: PMC9853098 DOI: 10.1093/nargab/lqad006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 12/07/2022] [Accepted: 01/09/2023] [Indexed: 01/22/2023] Open
Abstract
The establishment of experimental conditions for transcriptional regulator network (TRN) reconstruction in bacteria continues to be impeded by the limited knowledge of activating conditions for transcription factors (TFs). Here, we present a novel genome-scale model-driven workflow for designing experimental conditions, which optimally activate specific TFs. Our model-driven workflow was applied to elucidate transcriptional regulation under nitrogen limitation by Nac and NtrC, in Escherichia coli. We comprehensively predict alternative nitrogen sources, including cytosine and cytidine, which trigger differential activation of Nac using a model-driven workflow. In accordance with the prediction, genome-wide measurements with ChIP-exo and RNA-seq were performed. Integrative data analysis reveals that the Nac and NtrC regulons consist of 97 and 43 genes under alternative nitrogen conditions, respectively. Functional analysis of Nac at the transcriptional level showed that Nac directly down-regulates amino acid biosynthesis and restores expression of tricarboxylic acid (TCA) cycle genes to alleviate nitrogen-limiting stress. We also demonstrate that both TFs coherently modulate α-ketoglutarate accumulation stress due to nitrogen limitation by co-activating amino acid and diamine degradation pathways. A systems-biology approach provided a detailed and quantitative understanding of both TF's roles and how nitrogen and carbon metabolic networks respond complementarily to nitrogen-limiting stress.
Collapse
Affiliation(s)
- Joon Young Park
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Sang-Mok Lee
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Ali Ebrahim
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Zoe K Scott-Nevros
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jaehyung Kim
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Laurence Yang
- Department of Chemical Engineering, Queen's University, Kingston, Canada
| | - Anand Sastry
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sang Woo Seo
- School of Chemical and Biological Engineering, and Interdisciplinary Program in Bioengineering, and Institute of Chemical Processes, and Bio-MAX Institute, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea
| | - Bernhard O Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA
- The Novo Nordisk Foundation Center for Biosustainability, Danish Technical University, 6 Kogle Alle, Hørsholm, Denmark
| | - Donghyuk Kim
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| |
Collapse
|
37
|
A Genome-Scale Metabolic Model of Marine Heterotroph Vibrio splendidus Strain 1A01. mSystems 2023; 8:e0037722. [PMID: 36853050 PMCID: PMC10134806 DOI: 10.1128/msystems.00377-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
While Vibrio splendidus is best known as an opportunistic pathogen in oysters, Vibrio splendidus strain 1A01 was first identified as an early colonizer of synthetic chitin particles incubated in seawater. To gain a better understanding of its metabolism, a genome-scale metabolic model (GSMM) of V. splendidus 1A01 was reconstructed. GSMMs enable us to simulate all metabolic reactions in a bacterial cell using flux balance analysis. A draft model was built using an automated pipeline from BioCyc. Manual curation was then performed based on experimental data, in part by gap-filling metabolic pathways and tailoring the model's biomass reaction to V. splendidus 1A01. The challenges of building a metabolic model for a marine microorganism like V. splendidus 1A01 are described. IMPORTANCE A genome-scale metabolic model of V. splendidus 1A01 was reconstructed in this work. We offer solutions to the technical problems associated with model reconstruction for a marine bacterial strain like V. splendidus 1A01, which arise largely from the high salt concentration found in both seawater and culture media that simulate seawater.
Collapse
|
38
|
Wu C, Mori M, Abele M, Banaei-Esfahani A, Zhang Z, Okano H, Aebersold R, Ludwig C, Hwa T. Enzyme expression kinetics by Escherichia coli during transition from rich to minimal media depends on proteome reserves. Nat Microbiol 2023; 8:347-359. [PMID: 36737588 PMCID: PMC9994330 DOI: 10.1038/s41564-022-01310-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 12/15/2022] [Indexed: 02/05/2023]
Abstract
Bacterial fitness depends on adaptability to changing environments. In rich growth medium, which is replete with amino acids, Escherichia coli primarily expresses protein synthesis machineries, which comprise ~40% of cellular proteins and are required for rapid growth. Upon transition to minimal medium, which lacks amino acids, biosynthetic enzymes are synthesized, eventually reaching ~15% of cellular proteins when growth fully resumes. We applied quantitative proteomics to analyse the timing of enzyme expression during such transitions, and established a simple positive relation between the onset time of enzyme synthesis and the fractional enzyme 'reserve' maintained by E. coli while growing in rich media. We devised and validated a coarse-grained kinetic model that quantitatively captures the enzyme recovery kinetics in different pathways, solely on the basis of proteomes immediately preceding the transition and well after its completion. Our model enables us to infer regulatory strategies underlying the 'as-needed' gene expression programme adopted by E. coli.
Collapse
Affiliation(s)
- Chenhao Wu
- Department of Physics, U.C. San Diego, La Jolla, CA, USA.
| | - Matteo Mori
- Department of Physics, U.C. San Diego, La Jolla, CA, USA
| | - Miriam Abele
- Bavarian Center for Biomolecular Mass Spectrometry, Technical University of Munich, Freising, Germany
- Chair of Proteomics and Bioanalytics, Technical University of Munich, Freising, Germany
| | - Amir Banaei-Esfahani
- Department of Biology, Institute of Molecular Systems Biology, ETH, Zurich, Switzerland
| | - Zhongge Zhang
- Division of Biological Sciences, U.C. San Diego, La Jolla, CA, USA
| | - Hiroyuki Okano
- Department of Physics, U.C. San Diego, La Jolla, CA, USA
| | - Ruedi Aebersold
- Department of Biology, Institute of Molecular Systems Biology, ETH, Zurich, Switzerland
- Faculty of Science, University of Zurich, Zurich, Switzerland
| | - Christina Ludwig
- Bavarian Center for Biomolecular Mass Spectrometry, Technical University of Munich, Freising, Germany.
| | - Terence Hwa
- Department of Physics, U.C. San Diego, La Jolla, CA, USA.
- Division of Biological Sciences, U.C. San Diego, La Jolla, CA, USA.
| |
Collapse
|
39
|
A Class IV Adenylate Cyclase, CyaB, Is Required for Capsule Polysaccharide Production and Biofilm Formation in Vibrio parahaemolyticus. Appl Environ Microbiol 2023; 89:e0187422. [PMID: 36602323 PMCID: PMC9888186 DOI: 10.1128/aem.01874-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Cyclic AMP (cAMP) receptor protein (CRP), encoded by crp, is a global regulator that is activated by cAMP, a second messenger synthesized by a class I adenylate cyclase (AC-I) encoded by cyaA in Escherichia coli. cAMP-CRP is required for growth on nonpreferred carbon sources and is a global regulator. We constructed in-frame nonpolar deletions of the crp and cyaA homologs in Vibrio parahaemolyticus and found that the Δcrp mutant did not grow in minimal media supplemented with nonpreferred carbon sources, but the ΔcyaA mutant grew similarly to the wild type. Bioinformatics analysis of the V. parahaemolyticus genome identified a 181-amino-acid protein annotated as a class IV adenylate cyclase (AC-IV) named CyaB, a member of the CYTH protein superfamily. AC-IV phylogeny showed that CyaB was present in Gammaproteobacteria and Alphaproteobacteria as well as Planctomycetes and Archaea. Only the bacterial CyaB proteins contained an N-terminal motif, HFxxxxExExK, indicative of adenylyl cyclase activity. Both V. parahaemolyticus cyaA and cyaB genes functionally complemented an E. coli ΔcyaA mutant. The Δcrp and ΔcyaB ΔcyaA mutants showed defects in growth on nonpreferred carbon sources and in swimming and swarming motility, indicating that cAMP-CRP is an activator. The ΔcyaA and ΔcyaB single mutants had no defects in these phenotypes, indicating that AC-IV complements AC-I. Capsule polysaccharide and biofilm production assays showed significant defects in the Δcrp, ΔcyaBΔcyaA, and ΔcyaB mutants, whereas the ΔcyaA strain behaved similarly to the wild type. This is consistent with a role of cAMP-CRP as an activator of these phenotypes and establishes a cellular role for AC-IV in capsule and biofilm formation, which to date has been unestablished. IMPORTANCE Here, we characterized the roles of CRP and CyaA in V. parahaemolyticus, showing that cAMP-CRP is an activator of metabolism, motility, capsule production, and biofilm formation. These results are in contrast to cAMP-CRP in V. cholerae, which represses capsule and biofilm formation. Previously, only an AC-I CyaA had been identified in Vibrio species. Our data showed that an AC-IV CyaB homolog is present in V. parahaemolyticus and is required for optimal growth. The data demonstrated that CyaB is essential for capsule production and biofilm formation, uncovering a physiological role of AC-IV in bacteria. The data showed that the cyaB gene was widespread among Vibrionaceae species and several other Gammaproteobacteria, but in general, its phylogenetic distribution was limited. Our phylogenetic analysis also demonstrated that in some species the cyaB gene was acquired by horizontal gene transfer.
Collapse
|
40
|
Zhu M, Dai X. Stringent response ensures the timely adaptation of bacterial growth to nutrient downshift. Nat Commun 2023; 14:467. [PMID: 36709335 PMCID: PMC9884231 DOI: 10.1038/s41467-023-36254-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 01/20/2023] [Indexed: 01/30/2023] Open
Abstract
Timely adaptation to nutrient downshift is crucial for bacteria to maintain fitness during feast and famine cycle in the natural niche. However, the molecular mechanism that ensures the timely adaption of bacterial growth to nutrient downshift remains poorly understood. Here, we quantitatively investigated the adaptation of Escherichia coli to various kinds of nutrient downshift. We found that relA deficient strain, which is devoid of stringent response, exhibits a significantly longer growth lag than wild type strain during adapting to both amino acid downshift and carbon downshift. Quantitative proteomics show that increased (p)ppGpp level promotes the growth adaption of bacteria to amino acid downshift via triggering the proteome resource re-allocation from ribosome synthesis to amino acid biosynthesis. Such type of proteome re-allocation is significantly delayed in the relA-deficient strain, which underlies its longer lag than wild type strain during amino acid downshift. During carbon downshift, a lack of stringent response in relA deficient strain leads to disruption of the transcription-translation coordination, thus compromising the transcription processivity and further the timely expression of related catabolic operons for utilizing secondary carbon sources. Our studies shed light on the fundamental strategy of bacteria to maintain fitness under nutrient-fluctuating environments.
Collapse
Affiliation(s)
- Manlu Zhu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei Province, China.
| | - Xiongfeng Dai
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei Province, China.
| |
Collapse
|
41
|
Chakraborty S, Singh P, Seshasayee ASN. Understanding the Genome-Wide Transcription Response To Various cAMP Levels in Bacteria Using Phenomenological Models. mSystems 2022; 7:e0090022. [PMID: 36409084 PMCID: PMC9765429 DOI: 10.1128/msystems.00900-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 10/17/2022] [Indexed: 11/23/2022] Open
Abstract
Attempts to understand gene regulation by global transcription factors have largely been limited to expression studies under binary conditions of presence and absence of the transcription factor. Studies addressing genome-wide transcriptional responses to changing transcription factor concentration at high resolution are lacking. Here, we create a data set containing the entire Escherichia coli transcriptome in Luria-Bertani (LB) broth as it responds to 10 different cAMP concentrations spanning the biological range. We use the Hill's model to accurately summarize individual gene responses into three intuitively understandable parameters, Emax, n, and k, reflecting the sensitivity, nonlinearity, and midpoint of the dynamic range. Our data show that most cAMP-regulated genes have an n of >2, with their k values centered around the wild-type concentration of cAMP. Additionally, cAMP receptor protein (CRP) affinity to a promoter is correlated with Emax but not k, hinting that a high-affinity CRP promoter need not ensure transcriptional activation at lower cAMP concentrations and instead affects the magnitude of the response. Finally, genes belonging to different functional classes are tuned to have different k, n, and Emax values. We demonstrate that phenomenological models are a better alternative for studying gene expression trends than classical clustering methods, with the phenomenological constants providing greater insights into how genes are tuned in a regulatory network. IMPORTANCE Different genes may follow different trends in response to various transcription factor concentrations. In this study, we ask two questions: (i) what are the trends that different genes follow in response to changing transcription factor concentrations and (ii) what methods can be used to extract information from the gene trends so obtained. We demonstrate a method to analyze transcription factor concentration-dependent genome-wide expression data using phenomenological models. Conventional clustering methods and principal-component analysis (PCA) can be used to summarize trends in data but have limited interpretability. The use of phenomenological models greatly enhances the interpretability and thus utility of conventional clustering. Transformation of dose-response data into phenomenological constants opens up avenues to ask and answer many different kinds of question. We show that the phenomenological constants obtained from the model fits can be used to generate insights about network topology and allows integration of other experimental data such as chromatin immunoprecipitation sequencing (ChIP-seq) to understand the system in greater detail.
Collapse
Affiliation(s)
- Shweta Chakraborty
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India
| | | | - Aswin Sai Narain Seshasayee
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India
| |
Collapse
|
42
|
Poudel S, Hefner Y, Szubin R, Sastry A, Gao Y, Nizet V, Palsson BO. Coordination of CcpA and CodY Regulators in Staphylococcus aureus USA300 Strains. mSystems 2022; 7:e0048022. [PMID: 36321827 PMCID: PMC9765215 DOI: 10.1128/msystems.00480-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 10/10/2022] [Indexed: 11/07/2022] Open
Abstract
The complex cross talk between metabolism and gene regulatory networks makes it difficult to untangle individual constituents and study their precise roles and interactions. To address this issue, we modularized the transcriptional regulatory network (TRN) of the Staphylococcus aureus USA300 strain by applying independent component analysis (ICA) to 385 RNA sequencing samples. We then combined the modular TRN model with a metabolic model to study the regulation of carbon and amino acid metabolism. Our analysis showed that regulation of central carbon metabolism by CcpA and amino acid biosynthesis by CodY are closely coordinated. In general, S. aureus increases the expression of CodY-regulated genes in the presence of preferred carbon sources such as glucose. This transcriptional coordination was corroborated by metabolic model simulations that also showed increased amino acid biosynthesis in the presence of glucose. Further, we found that CodY and CcpA cooperatively regulate the expression of ribosome hibernation-promoting factor, thus linking metabolic cues with translation. In line with this hypothesis, expression of CodY-regulated genes is tightly correlated with expression of genes encoding ribosomal proteins. Together, we propose a coarse-grained model where expression of S. aureus genes encoding enzymes that control carbon flux and nitrogen flux through the system is coregulated with expression of translation machinery to modularly control protein synthesis. While this work focuses on three key regulators, the full TRN model we present contains 76 total independently modulated sets of genes, each with the potential to uncover other complex regulatory structures and interactions. IMPORTANCE Staphylococcus aureus is a versatile pathogen with an expanding antibiotic resistance profile. The biology underlying its clinical success emerges from an interplay of many systems such as metabolism and gene regulatory networks. This work brings together models for these two systems to establish fundamental principles governing the regulation of S. aureus central metabolism and protein synthesis. Studies of these fundamental biological principles are often confined to model organisms such as Escherichia coli. However, expanding these models to pathogens can provide a framework from which complex and clinically important phenotypes such as virulence and antibiotic resistance can be better understood. Additionally, the expanded gene regulatory network model presented here can deconvolute the biology underlying other important phenotypes in this pathogen.
Collapse
Affiliation(s)
- Saugat Poudel
- Department of Bioengineering, University of California San Diego, San Diego, California, USA
| | - Ying Hefner
- Department of Bioengineering, University of California San Diego, San Diego, California, USA
| | - Richard Szubin
- Department of Bioengineering, University of California San Diego, San Diego, California, USA
| | - Anand Sastry
- Department of Bioengineering, University of California San Diego, San Diego, California, USA
| | - Ye Gao
- Department of Bioengineering, University of California San Diego, San Diego, California, USA
- Department of Biological Sciences, University of California San Diego, San Diego, California, USA
| | - Victor Nizet
- Collaborative to Halt Antibiotic-Resistant Microbes (CHARM), Department of Pediatrics, University of California San Diego, San Diego, California, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, San Diego, California, USA
| | - Bernhard O. Palsson
- Department of Bioengineering, University of California San Diego, San Diego, California, USA
- Collaborative to Halt Antibiotic-Resistant Microbes (CHARM), Department of Pediatrics, University of California San Diego, San Diego, California, USA
| |
Collapse
|
43
|
Balakrishnan R, Mori M, Segota I, Zhang Z, Aebersold R, Ludwig C, Hwa T. Principles of gene regulation quantitatively connect DNA to RNA and proteins in bacteria. Science 2022; 378:eabk2066. [PMID: 36480614 PMCID: PMC9804519 DOI: 10.1126/science.abk2066] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Protein concentrations are set by a complex interplay between gene-specific regulatory processes and systemic factors, including cell volume and shared gene expression machineries. Elucidating this interplay is crucial for discerning and designing gene regulatory systems. We quantitatively characterized gene-specific and systemic factors that affect transcription and translation genome-wide for Escherichia coli across many conditions. The results revealed two design principles that make regulation of gene expression insulated from concentrations of shared machineries: RNA polymerase activity is fine-tuned to match translational output, and translational characteristics are similar across most messenger RNAs (mRNAs). Consequently, in bacteria, protein concentration is set primarily at the promoter level. A simple mathematical formula relates promoter activities and protein concentrations across growth conditions, enabling quantitative inference of gene regulation from omics data.
Collapse
Affiliation(s)
- Rohan Balakrishnan
- Department of Physics, University of California at San Diego, La Jolla, California 92093-0374
| | - Matteo Mori
- Department of Physics, University of California at San Diego, La Jolla, California 92093-0374
| | - Igor Segota
- Departments of Medicine and Pharmacology, University of California at San Diego, La Jolla, California 92093
| | - Zhongge Zhang
- Section of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, California 92093
| | - Ruedi Aebersold
- Faculty of Science, University of Zurich, Zurich, Switzerland
- Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, Switzerland
| | - Christina Ludwig
- Bavarian Center for Biomolecular Mass Spectrometry (BayBioMS), Technical University of Munich (TUM), Freising, Germany
| | - Terence Hwa
- Department of Physics, University of California at San Diego, La Jolla, California 92093-0374
- Section of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, California 92093
| |
Collapse
|
44
|
Mu H, Han F, Wang Q, Wang Y, Dai X, Zhu M. Recent functional insights into the magic role of (p)ppGpp in growth control. Comput Struct Biotechnol J 2022; 21:168-175. [PMID: 36544478 PMCID: PMC9747358 DOI: 10.1016/j.csbj.2022.11.063] [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: 10/14/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
Rapid growth and survival are two key traits that enable bacterial cells to thrive in their natural habitat. The guanosine tetraphosphate and pentaphosphate [(p)ppGpp], also known as "magic spot", is a key second messenger inside bacterial cells as well as chloroplasts of plants and green algae. (p)ppGpp not only controls various stages of central dogma processes (replication, transcription, ribosome maturation and translation) and central metabolism but also regulates various physiological processes such as pathogenesis, persistence, motility and competence. Under extreme conditions such as nutrient starvation, (p)ppGpp-mediated stringent response is crucial for the survival of bacterial cells. This mini-review highlights some of the very recent progress on the key role of (p)ppGpp in bacterial growth control in light of cellular resource allocation and cell size regulation. We also briefly discuss some recent functional insights into the role of (p)ppGpp in plants and green algae from the angle of growth and development and further discuss several important open directions for future studies.
Collapse
Affiliation(s)
| | | | - Qian Wang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei Province, China
| | - Yanling Wang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei Province, China
| | - Xiongfeng Dai
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei Province, China
| | - Manlu Zhu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei Province, China
| |
Collapse
|
45
|
Optimization of the Biotreatment of GTL Process Water Using Pseudomonas aeruginosa Immobilized in PVA Hydrogel. Processes (Basel) 2022. [DOI: 10.3390/pr10122568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The COD reduction in gas to liquid (GTL) process water was optimized using response surface methodology (RSM). The biodegradation process was carried out in a spouted bed bioreactor (SBBR) using Pseudomonas aeruginosa immobilized in polyvinyl alcohol (PVA) gel. Different factors affecting the biological treatment of GTL process water (PW) were investigated. Three variables including PVA volume fraction, initial COD, and pH were investigated in the batch experiments. The biodegradation experiments were carried out by varying the initial COD values from 1000 to 3000 mg/L, pH from 5 to 8, and PVA v% from 20 to 30%. The maximum COD reduction was estimated to occur at an initial COD of 2595 mg/L, PVA v% of 27%, and pH of 7.3. At optimum conditions, the bioreactor system was able to achieve a maximum COD reduction of 89%, which is quite close to the RSM prediction value of 90%. The optimum operating conditions were used to carry out continuous biodegradation, and the results indicated that the COD reduction increased from 60% to 62% with an increase in the air flow rate from 2 to 3.3 La/Lr.min. However, by increasing the liquid flow rate from 2.1 to 4.2 mL/min and back to 2.1 mL/min, the COD reduction decreased from 66% to 39%. The system responded quickly to the change in liquid flow rate and returned to the initial COD level. This indicates that the system is highly stable and can easily recover.
Collapse
|
46
|
Schink S, Ammar C, Chang Y, Zimmer R, Basan M. Analysis of proteome adaptation reveals a key role of the bacterial envelope in starvation survival. Mol Syst Biol 2022; 18:e11160. [PMID: 36479616 PMCID: PMC9728487 DOI: 10.15252/msb.202211160] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 10/19/2022] [Accepted: 10/19/2022] [Indexed: 12/12/2022] Open
Abstract
Bacteria reorganize their physiology upon entry to stationary phase. What part of this reorganization improves starvation survival is a difficult question because the change in physiology includes a global reorganization of the proteome, envelope, and metabolism of the cell. In this work, we used several trade-offs between fast growth and long survival to statistically score over 2,000 Escherichia coli proteins for their global correlation with death rate. The combined ranking allowed us to narrow down the set of proteins that positively correlate with survival and validate the causal role of a subset of proteins. Remarkably, we found that important survival genes are related to the cell envelope, i.e., periplasm and outer membrane, because the maintenance of envelope integrity of E. coli plays a crucial role during starvation. Our results uncover a new protective feature of the outer membrane that adds to the growing evidence that the outer membrane is not only a barrier that prevents abiotic substances from reaching the cytoplasm but also essential for bacterial proliferation and survival.
Collapse
Affiliation(s)
- Severin Schink
- Systems Biology DepartmentHarvard Medical SchoolMABostonUSA
| | - Constantin Ammar
- Systems Biology DepartmentHarvard Medical SchoolMABostonUSA
- Institute of InformaticsLudwig‐Maximilians‐Universität MünchenMunichGermany
- Department of Proteomics and Signal TransductionMax Planck Institute of BiochemistryMartinsriedGermany
| | - Yu‐Fang Chang
- Systems Biology DepartmentHarvard Medical SchoolMABostonUSA
| | - Ralf Zimmer
- Institute of InformaticsLudwig‐Maximilians‐Universität MünchenMunichGermany
| | - Markus Basan
- Systems Biology DepartmentHarvard Medical SchoolMABostonUSA
| |
Collapse
|
47
|
Ma J, Chen X, Zhang L, Ma L, Li J, Li J, Zang J. The stability and absorption of naturally occurring cAMP by its weak interactions with jujube polysaccharides were greatly improved. Food Hydrocoll 2022. [DOI: 10.1016/j.foodhyd.2022.107957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
48
|
Xanthan gum modified fish gelatin and binary culture modulates the metabolism of probiotics in fermented milk mainly via amino acid metabolism pathways. Food Res Int 2022; 161:111844. [DOI: 10.1016/j.foodres.2022.111844] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 08/16/2022] [Accepted: 08/21/2022] [Indexed: 02/07/2023]
|
49
|
Zhang D, Li SHJ, King CG, Wingreen NS, Gitai Z, Li Z. Global and gene-specific translational regulation in Escherichia coli across different conditions. PLoS Comput Biol 2022; 18:e1010641. [PMID: 36264977 PMCID: PMC9624429 DOI: 10.1371/journal.pcbi.1010641] [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: 04/27/2022] [Revised: 11/01/2022] [Accepted: 10/06/2022] [Indexed: 11/05/2022] Open
Abstract
How well mRNA transcript levels represent protein abundances has been a controversial issue. Particularly across different environments, correlations between mRNA and protein exhibit remarkable variability from gene to gene. Translational regulation is likely to be one of the key factors contributing to mismatches between mRNA level and protein abundance in bacteria. Here, we quantified genome-wide transcriptome and relative translation efficiency (RTE) under 12 different conditions in Escherichia coli. By quantifying the mRNA-RTE correlation both across genes and across conditions, we uncovered a diversity of gene-specific translational regulations, cooperating with transcriptional regulations, in response to carbon (C), nitrogen (N), and phosphate (P) limitations. Intriguingly, we found that many genes regulating translation are themselves subject to translational regulation, suggesting possible feedbacks. Furthermore, a random forest model suggests that codon usage partially predicts a gene's cross-condition variability in translation efficiency; such cross-condition variability tends to be an inherent quality of a gene, independent of the specific nutrient limitations. These findings broaden the understanding of translational regulation under different environments and provide novel strategies for the control of translation in synthetic biology. In addition, our data offers a resource for future multi-omics studies.
Collapse
Affiliation(s)
- Di Zhang
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Sophia Hsin-Jung Li
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- Institute of Bioengineering, School of Life Sciences, Swiss Federal Institute of Technology Lausanne, Lausanne, Switzerland
- Global Health Institute, School of Life Sciences, Swiss Federal Institute of Technology Lausanne, Lausanne, Switzerland
| | - Christopher G. King
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Ned S. Wingreen
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- * E-mail: (NSW); (ZG); (ZL)
| | - Zemer Gitai
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- * E-mail: (NSW); (ZG); (ZL)
| | - Zhiyuan Li
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- * E-mail: (NSW); (ZG); (ZL)
| |
Collapse
|
50
|
Gu W, Müller AL, Deutzmann JS, Williamson JR, Spormann AM. Growth rate-dependent coordination of catabolism and anabolism in the archaeon Methanococcus maripaludis under phosphate limitation. THE ISME JOURNAL 2022; 16:2313-2319. [PMID: 35780255 PMCID: PMC9478154 DOI: 10.1038/s41396-022-01278-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 06/15/2022] [Accepted: 06/17/2022] [Indexed: 06/15/2023]
Abstract
Catabolic and anabolic processes are finely coordinated in microorganisms to provide optimized fitness under varying environmental conditions. Understanding this coordination and the resulting physiological traits reveals fundamental strategies of microbial acclimation. Here, we characterized the system-level physiology of Methanococcus maripaludis, a niche-specialized methanogenic archaeon, at different dilution rates ranging from 0.09 to 0.003 h-1 in chemostat experiments under phosphate (i.e., anabolic) limitation. Phosphate was supplied as the limiting nutrient, while formate was supplied in excess as the catabolic substrate and carbon source. We observed a decoupling of catabolism and anabolism resulting in lower biomass yield relative to catabolically limited cells at the same dilution rates. In addition, the mass abundance of several coarse-grained proteome sectors (i.e., combined abundance of proteins grouped based on their function) exhibited a linear relationship with growth rate, mostly ribosomes and their biogenesis. Accordingly, cellular RNA content also correlated with growth rate. Although the methanogenesis proteome sector was invariant, the metabolic capacity for methanogenesis, measured as methane production rates immediately after transfer to batch culture, correlated with growth rate suggesting translationally independent regulation that allows cells to only increase catabolic activity under growth-permissible conditions. These observations are in stark contrast to the physiology of M. maripaludis under formate (i.e., catabolic) limitation, where cells keep an invariant proteome including ribosomal content and a high methanogenesis capacity across a wide range of growth rates. Our findings reveal that M. maripaludis employs fundamentally different strategies to coordinate global physiology during anabolic phosphate and catabolic formate limitation.
Collapse
Affiliation(s)
- Wenyu Gu
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
| | - Albert L Müller
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
| | - Jörg S Deutzmann
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
| | - James R Williamson
- Department of Integrative Structural and Computational Biology, Department of Chemistry, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Alfred M Spormann
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA.
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA.
| |
Collapse
|