Subcompartmentalization and Pseudo‐Division of Model Protocells

Abstract

Membrane enclosed intracellular compartments have been exclusively associated with the eukaryotes, represented by the highly compartmentalized last eukaryotic common ancestor. Recent evidence showing the presence of membranous compartments with specific functions in archaea and bacteria makes it conceivable that the last universal common ancestor and its hypothetical precursor, the protocell, may have exhibited compartmentalization. To the authors’ knowledge, there are no experimental studies yet that have tested this hypothesis. They report on an autonomous subcompartmentalization mechanism for protocells which results in the transformation of initial subcompartments to daughter protocells. The process is solely determined by the fundamental materials properties and interfacial events, and does not require biological machinery or chemical energy supply. In the light of the authors’ findings, it is proposed that similar events may have taken place under early Earth conditions, leading to the development of compartmentalized cells and potentially, primitive division.

Spontaneous formation of prebiotic compartment colonies on Hadean Earth and pre-Noachian Mars

“…3f (also Fig. S5, S11 ) reveals the presence of subcompartments inside single, dome-shaped protocells, a phenomenon we had recently reported on artificial surfaces 17 . In the report, we pointed out a possible pathway to pseudo-division as the consequence of rupture of the enveloping surfactant shell.…”

“…S21 for another example). The transmembrane uptake occurs directly via transient membrane pores, which we characterized in earlier studies 16,17 .…”

“…Biosurfactant assemblies are, however, capable of amazingly versatile shape and phase transformations, requiring only tiny energy input. Our recent work shows that through the involvement of an artificial solid surface, strikingly sophisticated sequences of autonomous soft matter shape transformations are possible 15–17 . A potentially critical role of natural surfaces in enabling the formation and development of protocells has possibly been overlooked all along, until interactions of amphiphiles with solid mineral microparticles under formation of closed compartments was reported 18–21 .…”

“…The close proximity of colony vesicles can likely facilitate direct chemical exchange, e.g. through transient pores 17 .…”

Mixed fatty acid-phospholipid protocell networks

“…The P values increase with increasing fatty acid concentration and are spread out from very low to as high as 7*10 -6 cm/s. We have previously shown the encapsulation of fluorescein by surface adhered phospholipid compartments 1, 25 where we proposed the uptake to be via nano-sized transient pores and predicted the quantity of uptake with a finite element method (FEM)-based model 25 . The uptake rates presented in Fig.…”