Periodic Vesicle Formation in Tectonic Fault Zones--an Ideal Scenario for Molecular Evolution.

Christian Mayer,Ulrich Schreiber,María J Dávila

doi:10.1007/s11084-015-9411-z

Christian Mayer, Ulrich Schreiber + Show 1 more

Open Access

https://doi.org/10.1007/s11084-015-9411-z

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Abstract

Tectonic fault systems in the continental crust offer huge networks of interconnected channels and cavities. Filled mainly with water and carbon dioxide (CO2), containing a wide variety of hydrothermal chemistry and numerous catalytic surfaces, they may offer ideal reaction conditions for prebiotic chemistry. In these systems, an accumulation zone for organic compounds will develop at a depth of approximately 1 km where CO2 turns sub-critical and dissolved components precipitate. At this point, periodic pressure changes caused for example by tidal influences or geyser activity may generate a cyclic process involving repeated phase transitions of carbon dioxide. In the presence of amphiphilic compounds, this will necessarily lead to the transient formation of coated water droplets in the gas phase and corresponding vesicular structures in the aqueous environment. During this process, the concentration of organic components inside the droplets and vesicles would be drastically increased, allowing for favorable reaction conditions and, in case of the vesicles generated, large trans-membrane concentration gradients. Altogether, the process of periodic formation and destruction of vesicles could offer a perfect environment for molecular evolution in small compartments and for the generation of protocells. The basic process of vesicle formation is reproduced experimentally with a lipid in a water/CO2 system.

Highlights

There is no doubt that compartmentalization is a key issue in the early evolution of life, and was possibly necessary for the first living cells
With additional periodic pressure variations induced by tidal influences or geyser phenomena, a cyclic process can occur in which the transition scCO2 → gaseous CO2 (gCO2) induces the formation of water droplets covered by a monolayer of amphiphilic compounds
In an attempt to artificially reproduce the vesicle formation process described in Fig. 1, the key ingredients for the vesicles were combined with CO2 in a high pressure cell

Summary

Introduction

There is no doubt that compartmentalization is a key issue in the early evolution of life, and was possibly necessary for the first living cells. When interacting with another film of amphiphiles on the surface of bulk water, a double layer can be formed leading to a vesicle structure.

Results

Conclusion