Protocells are membrane-bound spheres formed from fatty molecules, thought to be similar to early living cell precursors.
Henning Dalhof/Science Photography Library
Structures similar to those enveloping living cells have demonstrated the ability to self-assemble in micrometeorites, hinting that dust across planets might contribute to life’s origins.
“If we can establish that protocells arise from micrometeorites here on Earth, it’s evident this could occur on other habitable planets,” states Irepgözen from Gomod, a Swedish research and education organization. “This brings me immense excitement.”
Various lipid molecules can spontaneously create membrane-bound spheres, referred to as protocells, as they resemble potential precursors to living cells. While this process can happen in solutions, Gözen is investigating methods to facilitate protocell formation on surfaces that typically do not foster such reactions.
Surfaces possess intrinsic energy, with exposed atoms lacking complete bonds, making them suitable for this transformation. “Creating a surface generates excess energy that seeks to be released,” she observes.
After recently analyzing Martian metstones, Gözen noted that their rough, grainy textures may enhance protocell formation. Consequently, she and her team introduced three types of micrometeorites into lipid suspensions. Post an overnight incubation, microscopic examination revealed the formation of protocells, especially in samples with lipids similar to those found in Archaea membranes.
Hundreds of micrometeorites exist, according to Gözen, and this study serves as an initial proof of concept. While the findings do not confirm the origin of the first living cells, Gözen finds the results intriguing, considering that simple organic compounds frequently appear in meteorites, and micrometeorites are probably widespread on planetary surfaces. “There’s a tiny nuclear reactor carrying intriguing prebiotic organic matter,” she remarks. “They’re falling on nearly every planet, all contained within one particle.”
“I find it exhilarating that micrometeorites possess sufficient surface energy to facilitate their [protocell] formation,” says Anna Wang from the University of Sydney, New South Wales, Australia. “I wasn’t trained in physics.”
Gözen emphasizes that protocells formed on surfaces exhibit remarkable characteristics. “There’s a significant difference between reactions occurring on surfaces and in solutions,” she explains. “They establish a network of intriguing protocells interconnected by minute nanotubes, enabling content transfer. This allows for a very basic form of signaling.”
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Source: www.newscientist.com
