Gas bubbles in rock pores - a nursery for life on Early Earth

Date:
December 7, 2021
Source:
Ludwig-Maximilians-Universita"t Mu"nchen
Summary:
Researchers create compelling scenario for the evolution of
membraneless microdroplets as the origin of life.



FULL STORY ========================================================================== Munich and Dresden based researchers create compelling scenario for the evolution of membraneless microdroplets as the origin of life.


========================================================================== Where and how did life begin on Early Earth more than 3.5 billion years
ago from non-living chemicals? Discovering the answer to this question
has long been debated and is a challenge for scientists. One thing
that scientists can look for is potential environments that allowed
life to spark. A key necessity for the first cells on Earth is the
ability to make compartments and evolve to facilitate the first chemical reactions. Membraneless coacervate microdroplets are excellent candidates
to describe protocells, with the ability to partition, concentrate
molecules and support biochemical reactions. Scientists have not yet
shown how those microdroplets could have evolved to start life on earth.

Researchers at LMU's Center for NanoScience (CeNS) and the Max Planck
Institute of Molecular Cell Biology and Genetics (MPI-CBG) in Dresden
now demonstrate for the first time, that the growth and division of membraneless microdroplets is possible in an environment which is similar
to gas bubbles within a heated rock pore on Early Earth. Suggesting that
life may have had its origin there.

The team around Dora Tang, a research group leader at the MPI-CBG, showed
in 2018 that simple RNA is active within membraneless microdroplets,
enabling a suitable chemical environment for the beginning of life. Those experiments were conducted in a simple aqueous environment, where
competing forces were balanced. Cells, however, need an environment where
they can continuously divide and evolve. To find a more suitable scenario
for the origin of life experiments, Dora Tang teamed up with Dieter Braun, professor for Systems Biophysics at LMU. His group developed conditions
with a non-balanced environment that allow multiple reactions in a single setting and where cells could evolve. Those cells though are not like
the cells we know today, but more like precursors to today's cells,
also called protocells, made of coacervates with no membrane.

The environment, created by the Braun lab is a likely scenario on Early
Earth, where porous rocks in water in proximity of volcanic activities
were partially heated. For their experiments, Dora Tang and Dieter Braun
used water-containing pores with a gas bubble and a thermal gradient
(a hot and a cold pole) in order to see if the protocells would divide
and evolve. Alan Ianeselli, first author of the study and PhD student
in the lab of Dieter Braun, explains: "We knew that the interface of the
gas and the water attracted molecules. Protocells localize and accumulate there, and assemble into larger ones. This is why we chose this particular setting." The researchers indeed observed that molecules and protocells
went to the gas-water interface to form larger protocells out of sugar,
amino acids and RNA. Alan continues: "We also observed that the protocells
were able to divide and fragment. These results represent a possible
mechanism for the growth and division of membrane-free protocells on the
Early Earth." In addition to division and evolution, the researchers found
that as a consequence of the thermal gradient, several types of protocells
with different chemical composition, size and physical properties had
formed. Therefore, the thermal gradient in this environment could have
driven an evolutionary selection pressure on membraneless protocells.

Dora Tang and Dieter Braun, who supervised the study, summarize:
"This work shows for the first time that the gas bubble within a heated
rock pore is a convincing scenario for the evolution of membrane-free coacervate microdroplets on Early Earth. Future studies could focus on
more possible habitats and explore further conditions for life to emerge." ========================================================================== Story Source: Materials provided by
Ludwig-Maximilians-Universita"t_Mu"nchen. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Alan Ianeselli, Damla Tetiker, Julian Stein, Alexandra Ku"hnlein,
Christof B. Mast, Dieter Braun, T.-Y. Dora Tang. Non-equilibrium
conditions inside rock pores drive fission, maintenance and
selection of coacervate protocells. Nature Chemistry, 2021; DOI:
10.1038/s41557-021- 00830-y ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/12/211207152546.htm

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