Protocells self-assembling on micrometeorites hint at origins of life

It has been shown that the structures linked to the membrane similar to those which enclose living cells have proved spontaneously on micromèteorites, offering an endless index that dust scattered on the planets could play a role in the development of life.

“If we can show that protocels are formed on micromèteorites on earth, it is obvious that this could happen on other habitable planets,” explains Irep Gözen at Gomod, a research and education company in Sweden. “This is why it’s very exciting for me.”

Certain fat molecules called lipids can spontaneously form spheres linked to the membrane, which are sometimes called protocels because they think they resemble the precursors to living cells. Although this may happen in solution, Gözen has studied the way in which certain surfaces trigger the formation of protocols where it would not happen otherwise.

Surfaces have intrinsic energy that can fuel this type of transformation because the atoms on their side have not have a full set of links, she said. “As you create a surface, he will have this excess of energy which he wants to get rid of.”

After recently studied Martian meteorite, Gözen realized that the rough and granular areas of meteorites could be favorable to the formation of protocels. She and her colleagues have therefore placed three types of micromèteorites in dishes containing suspensions of various types of lipids. They left the samples during the night and then examined them under a microscope, noting that the protocels had actually formed. They were particularly prolific in the samples which contained the same lipids as the membranes of single cells called archaea.

There are hundreds of types of micromèteorites, explains Gözen, so this study is only proof of initial concept. The results do not show that this is how the first living cells have formed, of course, but Gözen thinks that they are intriguing since simple organic compounds have often been found on meteorites and that micromèteorites are likely to be largely distributed on the surface of the planets everywhere. “You have a small reactor that carries the interesting prebiotic organic matter,” she says. “They rain on almost all planets. Everything is packed in a particle.”

“I think it is exciting that micromèteorites have sufficient surface energy to drive the [protocell] Training mechanism, “explains Anna Wang at the University of New South Wales in Australia.” Physics was not given. »»

Gözen says that the protocities that are formed on surfaces also have interesting properties. “There is a huge difference in terms of what is happening in surfaces in relation to the solution,” she says. “They form these interesting networks of protocels with few nanotubular connections between the two, so that they can really transfer their content. They can make a very rudimentary form of signaling. ”