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Growth and division of active droplets provides a model for protocells

Abstract

It has been proposed that during the early steps in the origin of life, small droplets could have formed via the segregation of molecules from complex mixtures by phase separation. These droplets could have provided chemical reaction centres. However, whether these droplets could divide and propagate is unclear. Here we examine the behaviour of droplets in systems that are maintained away from thermodynamic equilibrium by an external supply of energy. In these systems, droplets grow by the addition of droplet material generated by chemical reactions. Surprisingly, we find that chemically driven droplet growth can lead to shape instabilities that trigger the division of droplets into two smaller daughters. Therefore, chemically active droplets can exhibit cycles of growth and division that resemble the proliferation of living cells. Dividing active droplets could serve as a model for prebiotic protocells, where chemical reactions in the droplet play the role of a prebiotic metabolism.

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Figure 1: Division of chemically active droplets.
Figure 2: Reaction rates and energy supply.
Figure 3: Reaction flux, concentration profile and diffusion flux in an effective droplet model.
Figure 4: Stationary droplet radii and stability diagrams.
Figure 5: Cycles of growth and divisions.

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References

  1. Oparin, A. I. Origin of Life (Dover, 1952).

    Google Scholar 

  2. Haldane, J. B. S. The origin of life. Ration. Annu. 148, 3–10 (1929).

    Google Scholar 

  3. Brangwynne, C. P. et al. Germline P granules are liquid droplets that localize by controlled dissolution/condensation. Science 324, 1729–1732 (2009).

    Article  ADS  Google Scholar 

  4. Koga, S., Williams, D. S., Perriman, A. W. & Mann, S. Peptide-nucleotide microdroplets as a step towards a membrane-free protocell model. Nat. Chem. 3, 720–724 (2011).

    Article  Google Scholar 

  5. Crosby, J. et al. Stabilization and enhanced reactivity of actinorhodin polyketide synthase minimal complex in polymer–nucleotide coacervate droplets. Chem. Commun. 48, 11832 (2012).

    Article  Google Scholar 

  6. Sokolova, E. et al. Enhanced transcription rates in membrane-free protocells formed by coacervation of cell lysate. Proc. Natl Acad. Sci. USA 110, 11692–11697 (2013).

    Article  ADS  Google Scholar 

  7. Hyman, A. A., Weber, C. A. & Jülicher, F. Liquid-liquid phase separation in biology. Annu. Rev. Cell Dev. Biol. 30, 39–58 (2014).

    Article  Google Scholar 

  8. Tang, T.-Y. D., van Swaay, D., DeMello, A., Ross Anderson, J. L. & Mann, S. In vitro gene expression within membrane-free coacervate protocells. Chem. Commun. 51, 11429–11432 (2015).

    Article  Google Scholar 

  9. Bray, A. Theory of phase-ordering kinetics. Adv. Phys. 43, 357–459 (1994).

    Article  ADS  Google Scholar 

  10. Ostwald, W. Studien über die Bildung und Umwandlung fester Körper. Z. Phys. Chem. 22, 289–330 (1897).

    Google Scholar 

  11. Lifshitz, I. M. & Slyozov, V. V. The kinetics of precipitation from supersaturated solid solutions. J. Phys. Chem. Solids 19, 35–50 (1961).

    Article  ADS  Google Scholar 

  12. Binder, K. & Stauffer, D. Statistical theory of nucleation, condensation and coagulation. Adv. Phys. 25, 343–396 (1976).

    Article  ADS  Google Scholar 

  13. Voorhees, P. W. Ostwald ripening of two-phase mixtures. Annu. Rev. Mater. Sci. 22, 197–215 (1992).

    Article  ADS  Google Scholar 

  14. Zwicker, D., Decker, M., Jaensch, S., Hyman, A. A. & Jülicher, F. Centrosomes are autocatalytic droplets of pericentriolar material organized by centrioles. Proc. Natl Acad. Sci. USA 111, E2636–E2645 (2014).

    Article  ADS  Google Scholar 

  15. Zwicker, D., Hyman, A. A. & Jülicher, F. Suppression of Ostwald ripening in active emulsions. Phys. Rev. E 92, 012317 (2015).

    Article  ADS  Google Scholar 

  16. Puri, S. & Frisch, H. Segregation dynamics of binary mixtures with simple chemical reactions. J. Phys. A 27, 6027–6038 (1994).

    Article  ADS  Google Scholar 

  17. Glotzer, S. C., Stauffer, D. & Jan, N. Monte Carlo simulations of phase separation in chemically reactive binary mixtures. Phys. Rev. Lett. 72, 4109–4112 (1994).

    Article  ADS  Google Scholar 

  18. Carati, D. & Lefever, R. Chemical freezing of phase separation in immiscible binary mixtures. Phys. Rev. E 56, 3127–3136 (1997).

    Article  ADS  Google Scholar 

  19. Huggins, M. L. Solutions of long chain compounds. J. Chem. Phys. 9, 440 (1941).

    Article  ADS  Google Scholar 

  20. Flory, P. I. Thermodynamics of high polymer solutions. J. Chem. Phys. 10, 51–61 (1942).

    Article  ADS  Google Scholar 

  21. Oparin, A. Proiskhozhedenie Zhizni Mosckovskii Rabochii (Reprinted and translated in JD Bernal (1967) The Origin of Life London; Weidenfeld and Nicolson, 1924).

  22. Turing, A. The chemical basis of morphogenesis. Phil. Trans. R. Soc. Lond. 237, 37–72 (1952).

    Article  MathSciNet  Google Scholar 

  23. Gierer, A. & Meinhardt, H. A theory of biological pattern formation. Biol. Cybern. 12, 30–39 (1972).

    MATH  Google Scholar 

  24. Mullins, W. W. & Sekerka, R. F. Morphological stability of a particle growing by diffusion or heat flow. J. Appl. Phys. 34, 323–329 (1963).

    Article  ADS  Google Scholar 

  25. Langer, J. S. Instabilities and pattern formation in crystal growth. Rev. Mod. Phys. 52, 1–28 (1980).

    Article  ADS  Google Scholar 

  26. Woese, C. R., Kandler, O. & Wheelis, M. L. Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya. Proc. Natl Acad. Sci. USA 87, 4576–4579 (1990).

    Article  ADS  Google Scholar 

  27. Fox, S. W. The evolutionary significance of phase-separated microsystems. Orig. Life 7, 49–68 (1976).

    Article  ADS  Google Scholar 

  28. Brangwynne, C. P. Soft active aggregates: mechanics, dynamics and self-assembly of liquid-like intracellular protein bodies. Soft Matter 7, 3052–3059 (2011).

    Article  ADS  Google Scholar 

  29. Toretsky, J. A. & Wright, P. E. Assemblages: functional units formed by cellular phase separation. J. Cell Biol. 206, 579–588 (2014).

    Article  Google Scholar 

  30. Weber, S. C. & Brangwynne, C. P. Getting RNA and protein in phase. Cell 149, 1188–1191 (2012).

    Article  Google Scholar 

  31. Elbaum-Garfinkle, S. et al. The disordered P granule protein LAF-1 drives phase separation into droplets with tunable viscosity and dynamics. Proc. Natl Acad. Sci. USA 112, 7189–7194 (2015).

    Article  ADS  Google Scholar 

  32. Molliex, A. et al. Phase separation by low complexity domains promotes stress granule assembly and drives pathological fibrillization article phase separation by low complexity domains promotes stress granule assembly and drives pathological fibrillization. Cell 163, 123–133 (2015).

    Article  Google Scholar 

  33. Lin, Y. et al. Formation and maturation of phase-separated liquid droplets by RNA-binding proteins article formation and maturation of phase-separated liquid droplets by RNA-binding proteins. Mol. Cell 60, 1–12 (2015).

    Article  Google Scholar 

  34. Gilbert, W. Origin of life: the RNA world. Nature 319, 618 (1986).

    Article  ADS  Google Scholar 

  35. Higgs, P. G. & Lehman, N. The RNA World: molecular cooperation at the origins of life. Nat. Rev. Genet. 16, 7–17 (2015).

    Article  Google Scholar 

  36. Fedor, M. J. & Williamson, J. R. The catalytic diversity of RNAs. Nat. Rev. Mol. Cell Biol. 6, 399–412 (2005).

    Article  Google Scholar 

  37. Unrau, P. J. & Bartel, D. P. RNA-catalysed nucleotide synthesis. Nature 395, 260–263 (1998).

    Article  ADS  Google Scholar 

  38. Hanczyc, M. M., Fujikawa, S. M. & Szostak, J. W. Experimental models of primitive cellular compartments: encapsulation, growth, and division. Science 302, 618–622 (2003).

    Article  ADS  Google Scholar 

  39. Hanczyc, M. M. & Szostak, J. W. Replicating vesicles as models of primitive cell growth and division. Curr. Opin. Chem. Biol. 8, 660–664 (2004).

    Article  Google Scholar 

  40. Macía, J. & Solé, R. V. Synthetic Turing protocells: vesicle self-reproduction through symmetry-breaking instabilities. Phil. Trans. R. Soc. B 362, 1821–1829 (2007).

    Article  Google Scholar 

  41. Murtas, G. Early self-reproduction, the emergence of division mechanisms in protocells. Mol. Biosyst. 9, 195–204 (2013).

    Article  Google Scholar 

  42. Browne, K. P., Walker, D. A., Bishop, K. J. M. & Grzybowski, B. A. Self-division of macroscopic droplets: partitioning of nanosized cargo into nanoscale micelles. Angew. Chem. Int. Ed. Engl. 49, 6756–6759 (2010).

    Article  Google Scholar 

  43. Patashinski, A. Z., Orlik, R., Paclawski, K., Ratner, M. A. & Grzybowski, B. A. The unstable and expanding interface between reacting liquids: theoretical interpretation of negative surface tension. Soft Matter 8, 1601–1608 (2012).

    Article  ADS  Google Scholar 

  44. Giomi, L. & DeSimone, A. Spontaneous division and motility in active nematic droplets. Phys. Rev. Lett. 112, 147802 (2014).

    Article  ADS  Google Scholar 

  45. Baross, J. & Hoffman, S. Submarine hydrothermal vents and associated gradient environments as sites for the origin and evolution of life. Orig. Life Evol. Biosph. 15, 327–345 (1985).

    Article  Google Scholar 

  46. Martin, W. F. Hydrogen, metals, bifurcating electrons, and proton gradients: the early evolution of biological energy conservation. FEBS Lett. 586, 485–493 (2012).

    Article  Google Scholar 

  47. Martin, W. F., Sousa, F. L. & Lane, N. Evolution. Energy at life’s origin. Science 344, 1092–1093 (2014).

    Article  ADS  Google Scholar 

  48. Atkins, P. & de Paula, J. Atkins’ Physical Chemistry (OUP Oxford, 2010).

    Google Scholar 

  49. Kacser, H., Burns, J. A. & Fell, D. A. The control of flux. Biochem. Soc. Trans. 23, 341–366 (1995).

    Article  Google Scholar 

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Acknowledgements

We would like to thank D. Tang for a critical reading of our manuscript.

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All authors developed the project and wrote the paper together. Numerical solutions of the continuum model were obtained by R.S. and D.Z.

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Correspondence to Frank Jülicher.

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The authors declare no competing financial interests.

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Zwicker, D., Seyboldt, R., Weber, C. et al. Growth and division of active droplets provides a model for protocells. Nature Phys 13, 408–413 (2017). https://doi.org/10.1038/nphys3984

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