The clay montmorillonite is known to catalyze the polymerization of RNA from activated ribonucleotides. Here we report that montmorillonite accelerates the spontaneous conversion of fatty acid micelles into vesicles. Clay particles often become encapsulated in these vesicles, thus providing a pathway for the prebiotic encapsulation of catalytically active surfaces within membrane vesicles. In addition, RNA adsorbed to clay can be encapsulated within vesicles. Once formed, such vesicles can grow by incorporating fatty acid supplied as micelles and can divide without dilution of their contents by extrusion through small pores. These processes mediate vesicle replication through cycles of growth and division. The formation, growth, and division of the earliest cells may have occurred in response to similar interactions with mineral particles and inputs of material and energy.
Category: Social Stream
The potential for self-replication makes RNA an attractive candidate as a primordial catalysis in the origin of life. Catalysis may have occurred in some kind of compartment, possibly a fatty acid vesicle. However, RNA catalysis generally requires high levels of magnesium, which are incompatible with fatty acid vesicle integrity. Adamala and Szostak (p. [1098][1]) screened magnesium chelators and found that several—including citrate, isocitrate, and oxalate—could maintain the membrane stability of fatty acid vesicles in the presence of Mg2+. Citrate also allowed Mg2+-dependent RNA synthesis within protocell-like vesicles, while at the same time protecting RNA from Mg2+-catalyzed degradation. Efforts to recreate a prebiotically plausible protocell, in which RNA replication occurs within a fatty acid vesicle, have been stalled by the destabilizing effect of Mg2+ on fatty acid membranes. Here we report that the presence of citrate protects fatty acid membranes from the disruptive effects of high Mg2+ ion concentrations while allowing RNA copying to proceed, while also protecting single-stranded RNA from Mg2+-catalyzed degradation. This combination of properties has allowed us to demonstrate the chemical copying of RNA templates inside fatty acid vesicles, which in turn allows for an increase in copying efficiency by bathing the vesicles in a continuously refreshed solution of activated nucleotides. [1]: /lookup/doi/10.1126/science.1241888
UNTIL recently, when one thought of the varied molecular processes at the origin of life, one imagined that the first self-replicating systems consisted of both RNA and protein. RNA served to hold information, whereas protein molecules provided all the enzymic activities needed to make copies of RNA and to reproduce themselves. The cycle that developed a self-replicating system out of the primitive soup of amino acids and nucleotides had two radically different components.
I just ran across Contently, a silo-based service specifically made for journalists, freelancers, and writers to aggregate their content into a portfolio as well as to help them with their careers. An intriguing concept that can use some additional UI research for integrating into an author platform.
Michael Marshall (Science)Hungarian biologist Tibor Gánti is an obscure figure. Now, more than a decade after his death, his ideas about how life began are finally coming to fruition.
Good to see Tibor Gánti finally getting some credit. This is a great little article with a nice overview of the Origin of Life problem (and references). The author Michael Marshall has a new book out on the topic.
ᔥ Peter Molnar in IndieWeb Chat ()
Directed by George Mastras. With Bryan Cranston, Anna Gunn, Aaron Paul, Dean Norris. Walter White's domestic life continues to deteriorate; at the same time, his growing business venture aims to steal a train car chock full of methylamine.
I’ve been away from this series for quite a while. Nice to get back to it after a long break.
Directed by Ed Thomas. With Richard Harrington, Mali Harries, Alex Harries, Hannah Daniel. A woman's suicide is thought to be related to another death. The independent investigator makes an admission to Mared which gives her a lead regarding the case she is investigating with Tom. More than one person stands in their way.
Interesting to hear the many pronunciations of Pontarfynach in this episode.
Many episodes of the series were almost painfully slow and could easily have been 60 minutes instead of 90 if the pace and the brooding were taken out. This final episode was a good cap for something that had been brewing since the end of the first season.
This is one of my favorite things on the internet. The past 24 hours of the Eiffel Tower in a one-minute time lapse animation. This one-minute video file is constantly updated throughout the day to reflect the past 24 hours of the Eiffel Tower. The source of these images comes from a live webcam. See … Eiffel Tower time lapse and Twitter account Read More »
A great Christmas surprise this year? Christmas ninjas! With these fun little guys around the house, you’ll find everyone asking, “Hey, what happened to the Christmas cookies?” Ninjas. These little guys bearing peppermint weapons will surely bring a fresh breath of air to your Christmas. They could cause all sorts of mischief around your house. … The awesome Christmas ninja toys from Oriental Trading Read More »
David Shanske (david.shanske.com)WordPress allows for custom archive templates. For the longest time, I’ve wanted to change the archive for my photo posts to show them in a photo grid. So, I’ve now done that at /kind/photo. You have to click the photo to see the full context, but I like the presentation of all photos I’ve posted. This does not include photos in other types of posts, but it’s probably the most visual item I’ve put out in a while. I hope it causes me to post more photos.
Rosemary Vrablic, who oversaw hundreds of millions of dollars in loans to President Trump’s company, will leave the bank next week.
Jeffrey Toobin didn’t get fired because his employers expect personal celibacy.
Someone was in need of a Diet Coke in the afternoon.