In the depths of a former copper mine in Northern California dwell what may be the smallest, most stripped-down forms of life ever discovered.
The microbes members of the domain of one-celled creatures called Archaea are smaller than other known microorganisms, rivaled in size only by a microbe that can survive solely as a parasite attached to the outside of other cells. Their genomes, reconstructed by a group at the University of California, Berkeley, are among the smallest ever reported.
The researchers also discovered another mine-dwelling microbe that occasionally produces weird protuberances unlike any structures seen before in Archaea and uses them to penetrate the ultra-small microbes.
"Other cells in the mine have what looks like a needle that sometimes pokes right into the cells," said Brett J. Baker, a researcher in UC Berkeley's Department of Earth and Planetary Science and first author of a new paper describing the findings. "It is really remarkable and suggests an interaction that has never been described before in nature."
These cellular extensions are only present when this interaction between the microbes is seen, noted co-author Luis R. Comolli, a microscopist at Lawrence Berkeley National Laboratory (LBNL).
Baker, Comolli and a team led by Jillian Banfield, UC Berkeley professor of earth and planetary science and of environmental science, policy and management and staff scientist at LBNL, published their findings last week in the online early edition of the journal Proceedings of the National Academy of Sciences.
Under a light microscope, the ultra-small microbes look like specks of dust. But Comolli used a state-of-the-art cryoelectron microscope, or cryoEM, to obtain high-resolution, 3-D images and even measure an individual microbe's internal volume between one-tenth and one-hundredth the volume of an E. coli bacterium. Each of the microbes, dubbed ARMAN,
|Contact: Robert Sanders|
University of California - Berkeley