Clay first appeared on the scene just as the time biomolecules started to develop into protocells and eventually membrane-confined cells.
According to a news release from Cornell University, clay may have been the birthplace of life on our planet.
“We propose that in early geological history clay hydrogel provided a confinement function for biomolecules and biochemical reactions,” noted Dan Luo, professor of biological and environmental engineering at Cornell University.
In simulated primitive seawater, clay develops a hydrogel — a collection of microscopic spaces able to soak up liquids just like a sponge. Over many years, chemicals contained in those space could resulted in complex reactions that developed proteins, DNA and all the components that help a living cell function. Clay hydrogels could have enclosed and shielded those chemical processes until the membrane that encircles living cells formed.
To further experiment with their idea, the researchers demonstrated protein synthesis in a clay hydrogel. Previously, they utilized synthetic hydrogels as a “cell-free” medium for protein generation. Fill the spongy material with DNA, amino acids, the right enzymes and a few components of cellular machinery and you can create the proteins for which the DNA encodes.
In order to make the process beneficial for generating large amounts of proteins, you need a lot of hydrogel, so the researchers were determined to discover a less expensive way to make it. Postdoctoral researcher Dayong Yang realized that clay developed a hydrogel. Not only is is dirt cheap, but utilizing clay improved protein production.
Earlier research has demonstrated that amino acids and other biomolecules could have been developed in ancient oceans, pulling energy from lightning or volcanic vents. But the researchers wondered how these molecules could come together frequently enough to gather into more advanced structures, and what shielded them from the rough environment.
Previously, researchers proposed that small balloons of fat or polymers might have acted as precursors of cell membranes. Clay is an excellent candidate for this role because biomolecules tend to join to its surface, and theorists have demonstrated that cytoplasm (the interior environment of a cell) acts much like a hydrogel.
According to researchers, clay first appeared on the scene just as the time biomolecules started to develop into protocells and eventually membrane-confined cells.
The researchers are now trying to figure out why a clay hydrogel works so well and what the practical applications for their findings might be.
The study’s results are discussed in greater detail in the journal Scientific Reports.
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