A simple physical mechanism enables homeostasis in primitive cells

Engelhart, Aaron E.; Adamala, Katarzyna P.; Szostak, Jack W.

doi:10.1038/nchem.2475

Cited by 102 publications

(97 citation statements)

References 19 publications

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“…Fatty acid retention has been an overlooked issue in terms of vesicle‐confined reactions. While fatty acids are compatible with many RNA‐based catalysts, fatty acids are known to inhibit a variety of protein‐based enzymes. For example, linoleic acid (C18) was reported to result in 50% inhibition of DNA polymerase α activity at a concentration of 35 × 10 −6 m and complete inhibition at 60 × 10 −6 m .…”

Section: Discussionmentioning

confidence: 99%

Fatty Acid/Phospholipid Blended Membranes: A Potential Intermediate State in Protocellular Evolution

Lin

Kamat

Jena

et al. 2018

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Prior to the evolution of membrane proteins, intrinsic membrane stability and permeability to polar solutes are essential features of a primitive cell membrane. These features are difficult to achieve simultaneously in model protocells made of either pure fatty acid or phospholipid membranes, raising the intriguing question of how the transition from fatty acid to phospholipid membranes might have occurred while continuously supporting encapsulated reactions required for genomic replication. Here, the properties of a blended membrane system composed of both oleic acid (OA), a monoacyl fatty acid, and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), a diacyl phospholipid are described. This hybrid vesicle system exhibits high stability to divalent cations (Mg ), while simultaneously maintaining its permeability to small charged molecules such as nucleotides and divalent ions such as Mg . This combination of features facilitates key reactions expected to occur during a transition from primitive to modern cells, including nonenzymatic RNA replication, and is also compatible with highly evolved functions such as the ribosomal translation of a protein. The observations support the hypothesis that the early transition from fatty acid to phospholipid membranes could be accomplished through intermediate states in which membranes are composed of amphiphile mixtures, and do not require protein transporters.

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Section: Discussionmentioning

confidence: 99%

Fatty Acid/Phospholipid Blended Membranes: A Potential Intermediate State in Protocellular Evolution

Lin

Kamat

Jena

et al. 2018

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“…[63][64][65] Due to their single-chain structure, the concentration of monomers in equilibrium with vesicles is significantly higher than for phospholipids, which enables fast flip-flop and exchange of molecules (Figure 2A). The growth process was also demonstrated under flow, [69] whereby filamentous microcompartments were formed, and also employed as a mechanism for ribozyme activation [70] to manifest a form of homeostasis. [66] A notable phenomenon, observed during the growth of oleate vesicles, was the so-called matrix effect, which exemplified itself when a seed of preformed vesicles was added to the micellar oleate solution, resulting in a narrow size distribution, corresponding to the size of the seed.…”

Section: Polymer-rich Dropletsmentioning

confidence: 99%

Directed Growth of Biomimetic Microcompartments

et al. 2019

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twilight zone), it is widely recognized that the formation of micro-and nanocompartments is an essential ingredient of all forms of life. This spatial constraint serves numerous purposes, including the segregation and protection from the environment (to allow for individuality and maintenance), the establishment of gradients (to enable and make use of outof-equilibrium conditions), and the role of 2D and 3D confinement for self-organization phenomena, all of which serve to overcome the overall "dilution problem." In order to fulfill another cornerstone of life-proliferation-compartments also need to change with time by fusion, growth, and division. In particular, the dynamic growth of compartments is an essential prerequisite for enabling selfreproduction as a fundamental life process, both in simplistic systems such as droplets or fatty acid-based vesicles, as well as for lipid vesicle compartments with membranes that resemble the biomembranes of today's cells. In this context, we argue that growth deserves more attention, not only because growth precedes division but also because of the difficulty to realize growth compared to division, especially in the case of lipid vesicles, where budding and division has been observed in response to various factors. This growth aspect has also been recognized in basic theoretical models of living systems such as Ganti's chemoton, [1,2] for which the increase of membrane area (referred to as membrane formation) was postulated to be one of three subsystems, characterizing living entities from a chemical viewpoint. The autopoietic theory was also centered on the membrane but focused on self-maintenance rather than on (self-)reproduction. [3,4] However, such a self-maintaining system could also enter a self-reproduction mode, manifested by growth, if homeostatic misbalance leads to excess membrane formation as shown in a thought experiment by Luisi. [3] In this progress report, we review the existing approaches for growth of compartments in the context of bottom-up synthetic biology and protobiology. We consider mainly micrometer-sized compartments due to their characteristic cellular dimensions; this feature also ensures that the area and curvature of the interface or the bounding membrane has less influence on the enclosed solution. Microcompartments of various origins and chemistries have been used as protocell models, and many studies have addressed growth and division simultaneously in an ambitious effort to mimic self-reproduction. Contemporary biological cells are sophisticated and highly compartmentalized. Compartmentalization is an essential principle of prebiotic life as well as a key feature in bottom-up synthetic biology research.In this review, the dynamic growth of compartments as an essential prerequisite for enabling self-reproduction as a fundamental life process is discussed. The micrometer-sized compartments are focused on due to their cellular dimensions. Two types of compartments are considered, membraneless droplets and membrane-bound microcompartments. Gr...

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“…In spite of the extraordinary diversity and complexity of cell systems, they are sharing some common features ( Figure ), such as growth, division, metabolism, energy supply, protein expression, communication, migration, and molecular transport . Living cells can communicate with the neighboring cells by secreting diffusible signaling molecules and these communication pathways facilitate information transduction among cells.…”

Section: Applications Of Fabricated Artificial Cellsmentioning

confidence: 99%

Microfluidics for Biosynthesizing: from Droplets and Vesicles to Artificial Cells

Xie

Xiong

et al. 2019

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Fabrication of artificial biomimetic materials has attracted abundant attention. As one of the subcategories of biomimetic materials, artificial cells are highly significant for multiple disciplines and their synthesis has been intensively pursued. In order to manufacture robust “alive” artificial cells with high throughput, easy operation, and precise control, flexible microfluidic techniques are widely utilized. Herein, recent advances in microfluidic‐based methods for the synthesis of droplets, vesicles, and artificial cells are summarized. First, the advances of droplet fabrication and manipulation on the T‐junction, flow‐focusing, and coflowing microfluidic devices are discussed. Then, the formation of unicompartmental and multicompartmental vesicles based on microfluidics are summarized. Furthermore, the engineering of droplet‐based and vesicle‐based artificial cells by microfluidics is also reviewed. Moreover, the artificial cells applied for imitating cell behavior and acting as bioreactors for synthetic biology are highlighted. Finally, the current challenges and future trends in microfluidic‐based artificial cells are discussed. This review should be helpful for researchers in the fields of microfluidics, biomaterial fabrication, and synthetic biology.

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A simple physical mechanism enables homeostasis in primitive cells

Cited by 102 publications

References 19 publications

Fatty Acid/Phospholipid Blended Membranes: A Potential Intermediate State in Protocellular Evolution

Fatty Acid/Phospholipid Blended Membranes: A Potential Intermediate State in Protocellular Evolution

Directed Growth of Biomimetic Microcompartments

Microfluidics for Biosynthesizing: from Droplets and Vesicles to Artificial Cells

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