HHMI investigator Jack Szostak and colleagues Martin M. Hanczyc and Shelly M. Fujikawa at Massachusetts General Hospital also demonstrated that these vesicles could be induced to grow and to split into separate vesicles under laboratory conditions. They reported their studies in the October 24, 2003, issue of the journal Science.

Szostak and his colleagues were prompted to perform their experiments by the earlier work of other researchers who had found that clays could catalyze the chemical reactions needed to construct RNA from building blocks called nucleotides. They reasoned that if clays could foster the formation of vesicles, it would not be inconceivable that clay particles that had RNA on their surface could end up inside such vesicles. If that were true, the result would offer conditions amenable to the eventual evolution of living cells that could self-reproduce.

"Other researchers had observed that if fatty acid micelles, which are stable at basic conditions, are exposed to more acidic conditions, they spontaneously assemble into vesicles," said Szostak. "This reaction has a long lag period, and some sort of nucleation surface is required to trigger the process. We reasoned that if the right kind of mineral surface was present, this lag phase would be eliminated."

In their experiments, Szostak and his colleagues found that adding small quantities of the clay, montmorillonite, to fatty acid micelles greatly accelerated the formation of vesicles. They also discovered that many other substances with negatively-charged surfaces also catalyzed formation of vesicles.

When the researchers loaded montmorillonite particles w
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Contact: Jim Keeley
keeleyj@hhmi.org
301-215-8858
Howard Hughes Medical Institute
23-Oct-2003