7 research outputs found
Protocells: Milestones and Recent Advances
The origin of life is still one of humankind\u27s great mysteries. At the transition between nonliving and living matter, protocells, initially featureless aggregates of abiotic matter, gain the structure and functions necessary to fulfill the criteria of life. Research addressing protocells as a central element in this transition is diverse and increasingly interdisciplinary. The authors review current protocell concepts and research directions, address milestones, challenges and existing hypotheses in the context of conditions on the early Earth, and provide a concise overview of current protocell research methods
Membranous Protocell Superstructures
How primitive cells emerged and developed on the early Earth remain an unsolved question. In contrast to the hypotheses that the first living cells evolved from a single ancestor, their development as colonies would provide numerous advantages, such as mechanical stability, enhancement of chemical reactions, and sharing of prebiotic molecules.
In this PhD thesis, the formation and development of colony-like primitive cell structures and populations was investigated using three simple ingredients: water, fat molecules and solid surfaces. Transformation of fat agglomerates into large populations of structured primitive cells that are able to communicate and migrate, was observed under a light microscope. The role of solid surfaces which were abundant on the early Earth in form of rocks and minerals, was shown to be fundamental for these processes.
These findings make us rethink the current theories on how life originated and show that solid surfaces might have played an important role in the emergence of primitive cells on the early Earth
Subcompartmentalization and Pseudo-Division of Model Protocells
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\u27 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\u27 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
Manipulation of Lipid Membranes with Thermal Stimuli
We describe a protocol for the assembly and application of infrared (IR-B) laser-based set-ups to\ua0be used for localized heating of solid-supported planar and vesicular lipid membrane assemblies
Colony-like protocell superstructures
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 nonenzymatic, strand displacement DNA reactions. The membrane
envelope is able to disassemble and expose individual daughter protocells,
which can migrate and attach via nanotethers to distant surface locations,
while maintaining their encapsulated contents. Some colonies feature
âexocompartmentsâ, which spontaneously extend out of
the enveloping bilayer, internalize DNA, and merge again with the
superstructure. A continuum elastohydrodynamic theory that we developed
suggests that a plausible driving force behind subcompartment formation
is 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 236 nm, above which the membrane
invaginations can form subcompartments. The findings support our hypotheses
that in extension of the âlipid world hypothesisâ, protocells
may have existed in the form of colonies, potentially benefiting from
the increased mechanical stability provided by a superstructure
Protocells: Milestones and Recent Advances
The origin of life is still one of humankind's great mysteries. At the transition between nonliving and living matter, protocells, initially featureless aggregates of abiotic matter, gain the structure and functions necessary to fulfill the criteria of life. Research addressing protocells as a central element in this transition is diverse and increasingly interdisciplinary. The authors review current protocell concepts and research directions, address milestones, challenges and existing hypotheses in the context of conditions on the early Earth, and provide a concise overview of current protocell research methods