A team of researchers at Harvard University have modeled in the laboratory a primitive cell, or protocell, that is capable of building, copying and containing DNA.
Since there are no physical records of what the first primitive cells on Earth looked like, or how they grew and divided, the research team's protocell project offers a useful way to learn about how Earth's earliest cells may have interacted with their environment approximately 3.5 billion years ago.
The protocell's fatty acid membrane allows chemical compounds, including the building blocks of DNA, to enter into the cell without the assistance of the protein channels and pumps required by today's highly developed cell membranes. Also unlike modern cells, the protocell does not use enzymes for copying its DNA.
Supported with funding from the National Science Foundation and led by Jack W. Szostak of the Harvard Medical School, the research team published its findings in the June 4, 2008, edition of the journal Nature's advance online publication.
"Szostak's group took a creative approach to this research challenge and made a significant contribution to our understanding of small molecule transport through membranes," said Luis Echegoyen, director of the NSF Division of Chemistry. "This is a great outcome of NSF's support of basic research."
Some scientists have proposed that ancient hydrothermal vents may have been sites where prebiotic molecules--molecules made before the origin of life, such as fatty acids and amino acids--were formed. An animation (accessible at upper right) created by Janet Iwasa of the Szostak Laboratory shows a theoretical scenario in which fatty acids are formed on the surface of minerals deep underground, and then brought to the surface by the eruption of a geyser.
When fatty acids are in an aqueous environment, they spontaneously arrange so that their hydrophilic, or water-loving, "heads" interact with the surrounding water molecules and their hydrophobic, or water-fearing, "tails" are shielded from the water, resulting in the formation of tiny spheres of fatty acids called micelles.
Depending upon chemical concentrations and the pH of their environment, micelles can convert into layered membrane sheets or enclosed vesicles. Researchers commonly use vesicles to model the cellular membranes of protocells. A second animation created by Iwasa (accessible at lower right) shows how vesicles may have been formed.
When the team started its work, the researchers were not sure that the building blocks required for copying the protocell's genetic material would be able to enter the cell.
"By showing that this can happen, and indeed happen quite efficiently, we have come a little closer to our goal of making a functional protocell that, in the right environment, is able to grow and divide on its own," said Szostak.
Co-authors of the Nature paper include Sheref S. Mansy, Jason P. Schrum, Mathangi Krishnamurthy, Sylvia Tobe and Douglas A. Treco of the Szostak Laboratory.
The research was supported by NSF Division of Chemistry award number 0434507. Jack W. Szostak was also supported by National Aeronautics and Space Administration Exobiology Program award number EXB02-0031-0018. Sheref S. Mansy was supported by National Institutes of Health award number F32 GM07450601.
Funding for Exploring Life's Origins Web site project was provided by NSF award number 0610117.Media Contacts
Show me your leaves - Health check for urban trees
12.12.2017 | Gesellschaft für Ökologie e.V.
Liver Cancer: Lipid Synthesis Promotes Tumor Formation
12.12.2017 | Universität Basel
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
12.12.2017 | Physics and Astronomy
12.12.2017 | Earth Sciences
12.12.2017 | Power and Electrical Engineering