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Villani M, Alboresi E, Serra R. Models of Protocells Undergoing Asymmetrical Division. ENTROPY (BASEL, SWITZERLAND) 2024; 26:281. [PMID: 38667835 PMCID: PMC11049191 DOI: 10.3390/e26040281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/13/2024] [Accepted: 03/23/2024] [Indexed: 04/28/2024]
Abstract
The conditions that allow for the sustained growth of a protocell population are investigated in the case of asymmetrical division. The results are compared to those of previous studies concerning models of symmetrical division, where synchronization (between duplication of the genetic material and fission of the lipid container) was found under a variety of different assumptions about the kinetic equations and about the place where molecular replication takes place. Such synchronization allows a sustained proliferation of the protocell population. In the asymmetrical case, there can be no true synchronization, since the time to duplication may depend upon the initial size, but we introduce a notion of homogeneous growth that actually allows for the sustained reproduction of a population of protocells. We first analyze Surface Reaction Models, defined in the text, and we show that in many cases they undergo homogeneous growth under the same kinetic laws that lead to synchronization in the symmetrical case. This is the case also for Internal Reaction Models (IRMs), which, however, require a deeper understanding of what homogeneous growth actually means, as discussed below.
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Affiliation(s)
- Marco Villani
- Department of Physics, Informatics and Mathematics, Modena and Reggio Emilia University, 41121 Modena, Italy; (E.A.); (R.S.)
- European Centre for Living Technology, 30123 Venice, Italy
| | - Elena Alboresi
- Department of Physics, Informatics and Mathematics, Modena and Reggio Emilia University, 41121 Modena, Italy; (E.A.); (R.S.)
| | - Roberto Serra
- Department of Physics, Informatics and Mathematics, Modena and Reggio Emilia University, 41121 Modena, Italy; (E.A.); (R.S.)
- European Centre for Living Technology, 30123 Venice, Italy
- Institute of Advanced Studies, University of Amsterdam, 1012 WX Amsterdam, The Netherlands
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2
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Girard C. The tri-flow adaptiveness of codes in major evolutionary transitions. Biosystems 2024; 237:105133. [PMID: 38336225 DOI: 10.1016/j.biosystems.2024.105133] [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: 11/17/2023] [Revised: 01/26/2024] [Accepted: 01/27/2024] [Indexed: 02/12/2024]
Abstract
Life codes increase in both number and variety with biological complexity. Although our knowledge of codes is constantly expanding, the evolutionary progression of organic, neural, and cultural codes in response to selection pressure remains poorly understood. Greater clarification of the selective mechanisms is achieved by investigating how major evolutionary transitions reduce spatiotemporal and energetic constraints on transmitting heritable code to offspring. Evolution toward less constrained flows is integral to enduring flow architecture everywhere, in both engineered and natural flow systems. Beginning approximately 4 billion years ago, the most basic level for transmitting genetic material to offspring was initiated by protocell division. Evidence from ribosomes suggests that protocells transmitted comma-free or circular codes, preceding the evolution of standard genetic code. This rudimentary information flow within protocells is likely to have first emerged within the geo-energetic and geospatial constraints of hydrothermal vents. A broad-gauged hypothesis is that major evolutionary transitions overcame such constraints with tri-flow adaptations. The interconnected triple flows incorporated energy-converting, spatiotemporal, and code-based informational dynamics. Such tri-flow adaptations stacked sequence splicing code on top of protein-DNA recognition code in eukaryotes, prefiguring the transition to sexual reproduction. Sex overcame the spatiotemporal-energetic constraints of binary fission with further code stacking. Examples are tubulin code and transcription initiation code in vertebrates. In a later evolutionary transition, language reduced metabolic-spatiotemporal constraints on inheritance by stacking phonetic, phonological, and orthographic codes. In organisms that reproduce sexually, each major evolutionary transition is shown to be a tri-flow adaptation that adds new levels of code-based informational exchange. Evolving biological complexity is also shown to increase the nongenetic transmissibility of code.
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Affiliation(s)
- Chris Girard
- Department of Global and Sociocultural Studies, Florida International University, Miami, FL 33199, United States.
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3
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Singh AY, Jain S. Multistable Protocells Can Aid the Evolution of Prebiotic Autocatalytic Sets. Life (Basel) 2023; 13:2327. [PMID: 38137928 PMCID: PMC10744544 DOI: 10.3390/life13122327] [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: 09/13/2023] [Revised: 10/27/2023] [Accepted: 10/28/2023] [Indexed: 12/24/2023] Open
Abstract
We present a simple mathematical model that captures the evolutionary capabilities of a prebiotic compartment or protocell. In the model, the protocell contains an autocatalytic set whose chemical dynamics is coupled to the growth-division dynamics of the compartment. Bistability in the dynamics of the autocatalytic set results in a protocell that can exist with two distinct growth rates. Stochasticity in chemical reactions plays the role of mutations and causes transitions from one growth regime to another. We show that the system exhibits 'natural selection', where a 'mutant' protocell in which the autocatalytic set is active arises by chance in a population of inactive protocells, and then takes over the population because of its higher growth rate or 'fitness'. The work integrates three levels of dynamics: intracellular chemical, single protocell, and population (or ecosystem) of protocells.
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Affiliation(s)
- Angad Yuvraj Singh
- Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India;
| | - Sanjay Jain
- Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India;
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
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4
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Nunes Palmeira R, Colnaghi M, Harrison SA, Pomiankowski A, Lane N. The limits of metabolic heredity in protocells. Proc Biol Sci 2022; 289:20221469. [PMID: 36350219 PMCID: PMC9653231 DOI: 10.1098/rspb.2022.1469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The universal core of metabolism could have emerged from thermodynamically favoured prebiotic pathways at the origin of life. Starting with H
2
and CO
2
, the synthesis of amino acids and mixed fatty acids, which self-assemble into protocells, is favoured under warm anoxic conditions. Here, we address whether it is possible for protocells to evolve greater metabolic complexity, through positive feedbacks involving nucleotide catalysis. Using mathematical simulations to model metabolic heredity in protocells, based on branch points in protometabolic flux, we show that nucleotide catalysis can indeed promote protocell growth. This outcome only occurs when nucleotides directly catalyse CO
2
fixation. Strong nucleotide catalysis of other pathways (e.g. fatty acids and amino acids) generally unbalances metabolism and slows down protocell growth, and when there is competition between catalytic functions cell growth collapses. Autocatalysis of nucleotide synthesis can promote growth but only if nucleotides also catalyse CO
2
fixation; autocatalysis alone leads to the accumulation of nucleotides at the expense of CO
2
fixation and protocell growth rate. Our findings offer a new framework for the emergence of greater metabolic complexity, in which nucleotides catalyse broad-spectrum processes such as CO
2
fixation, hydrogenation and phosphorylation important to the emergence of genetic heredity at the origin of life.
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Affiliation(s)
- Raquel Nunes Palmeira
- Department of Computer Science, Engineering Building, Malet Place, University College London, WC1E 7JG, UK
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Marco Colnaghi
- Department of Computer Science, Engineering Building, Malet Place, University College London, WC1E 7JG, UK
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Stuart A. Harrison
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Andrew Pomiankowski
- Department of Computer Science, Engineering Building, Malet Place, University College London, WC1E 7JG, UK
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Nick Lane
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
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5
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Gözen I, Köksal ES, Põldsalu I, Xue L, Spustova K, Pedrueza-Villalmanzo E, Ryskulov R, Meng F, Jesorka A. Protocells: Milestones and Recent Advances. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2106624. [PMID: 35322554 DOI: 10.1002/smll.202106624] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 02/06/2022] [Indexed: 06/14/2023]
Abstract
The origin of life is still one of humankind's great mysteries. At the transition between nonliving and living matter, protocells, initially featureless aggregates of abiotic matter, gain the structure and functions necessary to fulfill the criteria of life. Research addressing protocells as a central element in this transition is diverse and increasingly interdisciplinary. The authors review current protocell concepts and research directions, address milestones, challenges and existing hypotheses in the context of conditions on the early Earth, and provide a concise overview of current protocell research methods.
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Affiliation(s)
- Irep Gözen
- Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Oslo, 0318, Norway
| | - Elif Senem Köksal
- Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Oslo, 0318, Norway
| | - Inga Põldsalu
- Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Oslo, 0318, Norway
| | - Lin Xue
- Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Oslo, 0318, Norway
| | - Karolina Spustova
- Centre for Molecular Medicine Norway, Faculty of Medicine, University of Oslo, Oslo, 0318, Norway
| | - Esteban Pedrueza-Villalmanzo
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, SE-412 96, Sweden
- Department of Physics, University of Gothenburg, Universitetsplatsen 1, Gothenburg, 40530, Sweden
| | - Ruslan Ryskulov
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, SE-412 96, Sweden
| | - Fanda Meng
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, SE-412 96, Sweden
- School of Basic Medicine, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, 250000, China
| | - Aldo Jesorka
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, SE-412 96, Sweden
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6
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Li J, Baxani DK, Jamieson WD, Xu W, Rocha VG, Barrow DA, Castell OK. Formation of Polarized, Functional Artificial Cells from Compartmentalized Droplet Networks and Nanomaterials, Using One-Step, Dual-Material 3D-Printed Microfluidics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1901719. [PMID: 31921557 PMCID: PMC6947711 DOI: 10.1002/advs.201901719] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/04/2019] [Indexed: 05/05/2023]
Abstract
The bottom-up construction of synthetic cells with user-defined chemical organization holds considerable promise in the creation of bioinspired materials. Complex emulsions, droplet networks, and nested vesicles all represent platforms for the engineering of segregated chemistries with controlled communication, analogous to biological cells. Microfluidic manufacture of such droplet-based materials typically results in radial or axisymmetric structures. In contrast, biological cells frequently display chemical polarity or gradients, which enable the determination of directionality, and inform higher-order interactions. Here, a dual-material, 3D-printing methodology to produce microfluidic architectures that enable the construction of functional, asymmetric, hierarchical, emulsion-based artificial cellular chassis is developed. These materials incorporate droplet networks, lipid membranes, and nanoparticle components. Microfluidic 3D-channel arrangements enable symmetry-breaking and the spatial patterning of droplet hierarchies. This approach can produce internal gradients and hemispherically patterned, multilayered shells alongside chemical compartmentalization. Such organization enables incorporation of organic and inorganic components, including lipid bilayers, within the same entity. In this way, functional polarization, that imparts individual and collective directionality on the resulting artificial cells, is demonstrated. This approach enables exploitation of polarity and asymmetry, in conjunction with compartmentalized and networked chemistry, in single and higher-order organized structures, thereby increasing the palette of functionality in artificial cellular materials.
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Affiliation(s)
- Jin Li
- Cardiff University School of Pharmacy and Pharmaceutical SciencesRedwood Building, King Edward VII AveCardiffCF10 3NBUK
- Cardiff University School of EngineeringQueen's Buildings, 14‐17 The ParadeCardiffCF24 3AAUK
| | - Divesh Kamal Baxani
- Cardiff University School of Pharmacy and Pharmaceutical SciencesRedwood Building, King Edward VII AveCardiffCF10 3NBUK
| | - William David Jamieson
- Cardiff University School of Pharmacy and Pharmaceutical SciencesRedwood Building, King Edward VII AveCardiffCF10 3NBUK
| | - Wen Xu
- Cardiff Business School Cardiff UniversityAberconway Building, Colum DrCardiffCF10 3EUUK
| | - Victoria Garcia Rocha
- Cardiff University School of EngineeringQueen's Buildings, 14‐17 The ParadeCardiffCF24 3AAUK
| | - David Anthony Barrow
- Cardiff University School of EngineeringQueen's Buildings, 14‐17 The ParadeCardiffCF24 3AAUK
| | - Oliver Kieran Castell
- Cardiff University School of Pharmacy and Pharmaceutical SciencesRedwood Building, King Edward VII AveCardiffCF10 3NBUK
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7
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Serra R, Villani M. Sustainable Growth and Synchronization in Protocell Models. Life (Basel) 2019; 9:life9030068. [PMID: 31438465 PMCID: PMC6789472 DOI: 10.3390/life9030068] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 08/06/2019] [Accepted: 08/14/2019] [Indexed: 01/04/2023] Open
Abstract
The growth of a population of protocells requires that the two key processes of replication of the protogenetic material and reproduction of the whole protocell take place at the same rate. While in many ODE-based models such synchronization spontaneously develops, this does not happen in the important case of quadratic growth terms. Here we show that spontaneous synchronization can be recovered (i) by requiring that the transmembrane diffusion of precursors takes place at a finite rate, or (ii) by introducing a finite lifetime of the molecular complexes. We then consider reaction networks that grow by the addition of newly synthesized chemicals in a binary polymer model, and analyze their behaviors in growing and dividing protocells, thereby confirming the importance of (i) and (ii) for synchronization. We describe some interesting phenomena (like long-term oscillations of duplication times) and show that the presence of food-generated autocatalytic cycles is not sufficient to guarantee synchronization: in the case of cycles with a complex structure, it is often observed that only some subcycles survive and synchronize, while others die out. This shows the importance of truly dynamic models that can uncover effects that cannot be detected by static graph theoretical analyses.
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Affiliation(s)
- Roberto Serra
- Department of Physics, Informatics and Mathematics, Modena and Reggio Emilia University, Via Campi 213/A, 41125 Modena, Italy
- European Centre for Living Technology, Ca' Bottacin, Dorsoduro 3911, Calle Crosera, 30123 Venice, Italy
- Institute for Advanced Study, University of Amsterdam, Oude Turfmarkt 147, 1012 GC Amsterdam, The Netherlands
| | - Marco Villani
- Department of Physics, Informatics and Mathematics, Modena and Reggio Emilia University, Via Campi 213/A, 41125 Modena, Italy.
- European Centre for Living Technology, Ca' Bottacin, Dorsoduro 3911, Calle Crosera, 30123 Venice, Italy.
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8
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Population Dynamics of Autocatalytic Sets in a Compartmentalized Spatial World. Life (Basel) 2018; 8:life8030033. [PMID: 30126201 PMCID: PMC6161236 DOI: 10.3390/life8030033] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/13/2018] [Accepted: 08/18/2018] [Indexed: 12/30/2022] Open
Abstract
Autocatalytic sets are self-sustaining and collectively catalytic chemical reaction networks which are believed to have played an important role in the origin of life. Simulation studies have shown that autocatalytic sets are, in principle, evolvable if multiple autocatalytic subsets can exist in different combinations within compartments, i.e., so-called protocells. However, these previous studies have so far not explicitly modeled the emergence and dynamics of autocatalytic sets in populations of compartments in a spatial environment. Here, we use a recently developed software tool to simulate exactly this scenario, as an important first step towards more realistic simulations and experiments on autocatalytic sets in protocells.
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9
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From Systems to Organisations. SYSTEMS 2017. [DOI: 10.3390/systems5010023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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11
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Hordijk W, Steel M. Chasing the tail: The emergence of autocatalytic networks. Biosystems 2016; 152:1-10. [PMID: 28027958 DOI: 10.1016/j.biosystems.2016.12.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 12/13/2016] [Accepted: 12/15/2016] [Indexed: 10/20/2022]
Abstract
A ubiquitous feature of all living systems is their ability to sustain a biochemistry in which all reactions are coordinated by catalysts, and all reactants (along with the catalysts) are either produced by the system itself or are available from the environment. This led to the hypothesis that 'autocatalytic networks' play a key role in both the origin and the organization of life, which was first proposed in the early 1970s, and has been enriched in recent years by a combination of experimental studies and the application of mathematical and computational techniques. The latter have allowed a formalization and detailed analysis of such networks, by means of RAF theory. In this review, we describe the development of these ideas, from pioneering early work of Stuart Kauffman through to more recent theoretical and experimental studies. We conclude with some suggestions for future work.
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Affiliation(s)
- Wim Hordijk
- Konrad Lorenz Institute for Evolution and Cognition Research, Klosterneuburg, Austria.
| | - Mike Steel
- Biomathematics Research Centre, University of Canterbury, Christchurch, New Zealand.
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12
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Solé R. Synthetic transitions: towards a new synthesis. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150438. [PMID: 27431516 PMCID: PMC4958932 DOI: 10.1098/rstb.2015.0438] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2016] [Indexed: 12/17/2022] Open
Abstract
The evolution of life in our biosphere has been marked by several major innovations. Such major complexity shifts include the origin of cells, genetic codes or multicellularity to the emergence of non-genetic information, language or even consciousness. Understanding the nature and conditions for their rise and success is a major challenge for evolutionary biology. Along with data analysis, phylogenetic studies and dedicated experimental work, theoretical and computational studies are an essential part of this exploration. With the rise of synthetic biology, evolutionary robotics, artificial life and advanced simulations, novel perspectives to these problems have led to a rather interesting scenario, where not only the major transitions can be studied or even reproduced, but even new ones might be potentially identified. In both cases, transitions can be understood in terms of phase transitions, as defined in physics. Such mapping (if correct) would help in defining a general framework to establish a theory of major transitions, both natural and artificial. Here, we review some advances made at the crossroads between statistical physics, artificial life, synthetic biology and evolutionary robotics.This article is part of the themed issue 'The major synthetic evolutionary transitions'.
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Affiliation(s)
- Ricard Solé
- ICREA-Complex Systems Lab, Universitat Pompeu Fabra, Dr Aiguader 88, 08003 Barcelona, Spain Institut de Biologia Evolutiva, CSIC-UPF, Pg Maritim de la Barceloneta 37, 08003 Barcelona, Spain Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
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Rasmussen S, Constantinescu A, Svaneborg C. Generating minimal living systems from non-living materials and increasing their evolutionary abilities. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150440. [PMID: 27431518 PMCID: PMC4958934 DOI: 10.1098/rstb.2015.0440] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2016] [Indexed: 11/12/2022] Open
Abstract
We review lessons learned about evolutionary transitions from a bottom-up construction of minimal life. We use a particular systemic protocell design process as a starting point for exploring two fundamental questions: (i) how may minimal living systems emerge from non-living materials? and (ii) how may minimal living systems support increasingly more evolutionary richness? Under (i), we present what has been accomplished so far and discuss the remaining open challenges and their possible solutions. Under (ii), we present a design principle we have used successfully both for our computational and experimental protocellular investigations, and we conjecture how this design principle can be extended for enhancing the evolutionary potential for a wide range of systems.This article is part of the themed issue 'The major synthetic evolutionary transitions'.
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Affiliation(s)
- Steen Rasmussen
- Center for Fundamental Living Technology (FLinT), Department for Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
| | - Adi Constantinescu
- Center for Fundamental Living Technology (FLinT), Department for Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
| | - Carsten Svaneborg
- Center for Fundamental Living Technology (FLinT), Department for Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
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Emergent chemical behavior in variable-volume protocells. Life (Basel) 2015; 5:181-211. [PMID: 25590570 PMCID: PMC4390847 DOI: 10.3390/life5010181] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 01/04/2015] [Indexed: 02/03/2023] Open
Abstract
Artificial protocellular compartments and lipid vesicles have been used as model systems to understand the origins and requirements for early cells, as well as to design encapsulated reactors for biotechnology. One prominent feature of vesicles is the semi-permeable nature of their membranes, able to support passive diffusion of individual solute species into/out of the compartment, in addition to an osmotic water flow in the opposite direction to the net solute concentration gradient. Crucially, this water flow affects the internal aqueous volume of the vesicle in response to osmotic imbalances, in particular those created by ongoing reactions within the system. In this theoretical study, we pay attention to this often overlooked aspect and show, via the use of a simple semi-spatial vesicle reactor model, that a changing solvent volume introduces interesting non-linearities into an encapsulated chemistry. Focusing on bistability, we demonstrate how a changing volume compartment can degenerate existing bistable reactions, but also promote emergent bistability from very simple reactions, which are not bistable in bulk conditions. One particularly remarkable effect is that two or more chemically-independent reactions, with mutually exclusive reaction kinetics, are able to couple their dynamics through the variation of solvent volume inside the vesicle. Our results suggest that other chemical innovations should be expected when more realistic and active properties of protocellular compartments are taken into account.
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