Lab experiments suggest deep sea vents provide the right combination of warmth, alkalinity and salt to encourage the formation of protocells, the first step in the development of life. Photo courtesy of NOAA
Nov. 5 (UPI) -- Scientists have successfully produced protocells in hot, alkaline seawater, an experimental breakthrough that suggests deep sea vents provided ideal conditions for the origin of life.
"There are multiple competing theories as to where and how life started," Nick Lane, professor of evolutionary biochemistry at University College London, said in a news release. "Underwater hydrothermal vents are among most promising locations for life's beginnings -- our findings now add weight to that theory with solid experimental evidence."
Protocell synthesis is thought to be a key first step in the creation of cellular life forms, but previous attempts to produce protocells have failed.
The latest experiments suggest heat and alkalinity, high pH, were vital components of life's beginnings.
Inside deep sea vents, heat, water and minerals mix to create a warm, alkaline, hydrogen-rich environment. As water spews from these sea floor fissures, mineral-rich chimneys form, trapping alkaline and acidic fluids. These trapped chemical resources serve as fuel for chemical reactions between hydrogen and carbon dioxide, yielding more complex organic compounds.
Scientists have previously created protocells from fatty acids, but only in cool, freshwater environs. In previous experiments, when scientists transferred the protocells to hydrothermal vent-like environs, they quickly fell apart.
Researchers were able to correct hose failures by deploying a greater diversity of chemicals.
"Other experiments had all used a small number of molecule types, mostly with fatty acids of the same size, whereas in natural environments, you would expect to see a wider array of molecules," said UCL geneticist Sean Jordan.
For the new experiments, described this week in the journal Nature, researchers involved a greater diversity of fatty acids and fatty alcohols. The hydrothermal vent-like environment allowed for the production of protocells.
The heat helped molecules with longer carbon chains to combine and form protocells, or vesticles. The alkaline solution helped the protocells maintain their electric charge, and the salt water allowed fatty acids to form tighter bonds, ensuring the vesticles remained intact.
"In our experiments, we have created one of the essential components of life under conditions that are more reflective of ancient environments than many other laboratory studies," Jordan said. "We still don't know where life first formed, but our study shows that you cannot rule out the possibility of deep-sea hydrothermal vents."
Scientists have previously found hints of underwater hydrothermal activity on the moons of Saturn and Jupiter. If life on other planets exists, hydrothermal vents would be a good place to look for it.
