The latest research from the group has been published as two pre-prints on the bioRxiv server.
Colony-like Protocell Superstructures
The pre-print describes how primitive cells build bacterial colony-like structures. The research reports on the formation, growth, and dynamics of model protocell superstructures on solid surfaces, resembling single cell colonies. The work was carried out in collaboration with researchers from Virgina Tech, USA and Chalmers University, Sweden.
Abstract:
We report the formation, growth, and dynamics of model protocell superstructures on solid surfaces, resembling single cell colonies. These structures, consisting of several layers of lipidic compartments enveloped in a dome-shaped outer lipid bilayer, emerged as a result of spontaneous shape transformation of lipid agglomerates deposited on thin film aluminum surfaces. Collective protocell structures were observed to be mechanically more stable compared to isolated spherical compartments. We show that the model colonies encapsulate DNA and accommodate non-enzymatic, strand displacement DNA reactions. The membrane envelope is able to disassemble and expose individual daughter protocells, which can migrate and attach via nano-tethers to distant surface locations, while maintaining their encapsulated contents. Some colonies feature ‘exo-compartments’, which spontaneously extend out of the enveloping bilayer, internalize DNA, and merge again with the superstructure. A continuum elastohydrodynamic theory that we developed reveals that the subcompartment formation must be governed by attractive van der Waals (vdW) interactions between the membrane and surface. The balance between membrane bending and vdW interactions yields a critical length scale of 273 nm, above which the membrane invaginations can form subcompartments. The findings support our hypotheses that in extension of the ‘lipid world hypothesis’, protocells may have existed in the form of colonies, potentially benefiting from the increased mechanical stability provided by a superstructure.
Colony-like Protocell Superstructures: Karolina Spustova, Chinmay Katke, Esteban Pedrueza Villalmanzo, Ruslan Ryskulov, C. Nadir Kaplan, Irep Gözen. bioRxiv 2021.09.16.460583; doi: https://doi.org/10.1101/2021.09.16.460583
Transport among protocells via tunneling nanotubes
The research published here shows describes how primitive cells communicate with each other via tunnelling nanotubes.
Abstract:
We employ model protocell networks for evaluation of molecular transport through lipid nanotubes as potential means of communication among primitive cells on the early Earth. Network formation is initiated by deposition of multilamellar lipid reservoirs onto a silicon oxide surface in an aqueous environment. These reservoirs autonomously develop into surface-adhered protocells interconnected via lipid nanotubes, and encapsulate solutes from the ambient buffer in the process. We prepare networks in the presence of DNA and RNA and observe encapsulation of these molecules, and their diffusive transport between the lipid compartments via the interconnecting nanotubes. By means of an analytical model we determine key physical parameters affecting the transport, such as nanotube diameter and compartment size. We conclude that nanotube-mediated transport in self-organized nanotube-vesicle networks could have been a possible pathway of chemical communication between primitive, self-assembled protocells under early earth conditions, circumventing the necessity for crossing the membrane barrier. We suggest this transport within a closed protocell network as a feasible means of RNA and DNA exchange under primitive prebiotic conditions, possibly facilitating early replication.
Transport among protocells via tunneling nanotubes, Ingrid Jin Schanke, Lin Xue, Karolina Spustova, Irep Gözen. bioRxiv 2021.09.16.460285, doi: https://doi.org/10.1101/2021.09.16.460285