Scientists discover how surfaces may have helped early life on Earth begin

March 1, 2019, Biophysical Society
Spontaneously formed protocells, which resemble balloons anchored to a surface by a network of ropes, are visualized by 3D confocal microscopy. Credit: Irep Gözen

On early earth, a series of spontaneous events needed to happen in order for life as we know it to begin. One of those phenomena is the formation of compartments enclosed by lipid membranes. New research by Irep Gözen, Elif Koksal, and colleagues at the University of Oslo reveals, for the first time, how these vesicles can self-assemble on surfaces without external input. The team discovered the most straight-forward and plausible explanation so far with the simplest assumptions. They will present their research at the 63rd Biophysical Society Annual Meeting, to be held March 2—6, 2019 in Baltimore, Maryland.

Gözen's lab was originally focused on biomaterials, not origins of life research.

"We were actually trying to do another experiment and this came as a discovery," said Gözen. "The formation of tubes and the emergence of thousands of vesicles was happening spontaneously when we left lipids on a surface."

The lipids in their experiment were similar to those in bacteria membranes and have water-loving heads and water-avoiding tails. Because of these water-preferring properties, they spontaneously organize with their tails facing inward and their heads facing out. On the silicon dioxide surface, the lipids became sheets, with layers of these organized lipids. Due to the stickiness of the surface, at some points the two layers separate, and the top layer bulges out, creating tubes and then round balls as they gain more lipids. The entire process is fully autonomous. A gentle flow from the movement of liquid can then cause these vesicles to detach from the surface creating protocells, like those believed to be a stepping-stone to the origin of life.

"This is a new and novel means of compartmentalization," Gözen said.

It is conceivable that something similar happened on . Silicone dioxide, or silica, is one of the most abundant minerals on the earth's . Fatty molecules could have easily existed in the previological era, as confirmed by the results of their successful synthesis performed in possible primitive Earth conditions, together with their traces found in fossils and meteorites. Intriguingly, silicon dioxide was recently detected on Mars by the Curiosity Rover.

Another puzzle in life's beginnings is how got inside of protocells. It is not known whether the compartments formed around the already-existing lengthy genetic chains such as RNA, or if the small building blocks somehow found their way inside these tiny bubbles and made the chains inside. Gözen and colleagues added a light-emitting organic molecule similar in size to nucleotides, the genetic building blocks, to the surrounding of the bubbles. Such molecules which were too big to diffuse through the wall of the bubble, could get inside without compromising the protocells. They speculate it gets through transient defects or pores in the protocell wall.

"Our research may explain, for the first time, the details of self-directed transition from weakly organized lipids on solid surfaces to protocells with secluded internal contents," Gözen said.

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KBK
5 / 5 (1) Mar 01, 2019
Surface of the ocean: complex chemical stew of a 2d sheet catalytic boundary immersed in a unipolar pressured quantum level antagonist --namely....sunlight.

Something's gonna happen..with untold googleplexes of chemical monkeys typing away on a Googleplex of catalytic typewriters ...across a billion years.....
torbjorn_b_g_larsson
5 / 5 (1) Mar 02, 2019
Silica is produced by the alkaline hydrothermal vents that - so far - have been identified as the origin of the universal common ancestor [ https://www.natur...l2016116 ]. It was the kind of terrain where the Mars rover Spirit got stuck and ended its martian days, though it is not certain that the likely vents were alkaline [ https://www.ncbi....5473637/ ].
Da Schneib
5 / 5 (1) Mar 02, 2019
So now we have a way that cell walls form and a way that DNA and RNA can get inside these vesicles.

And if DNA and RNA can get in, so can amino acids. And they will form polypeptides. This may be a pointer to the origin of life. Now shake up with chaos chemistry and keep the ones that live.
Da Schneib
5 / 5 (1) Mar 02, 2019
And if anyone doubts chaos chemistry, note that it has already been done to create the enzymes in laundry detergent. Prosaic, but compelling.

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