The search for unusual alien life on Earth and life that can survive on Mars

April 21, 2009

New Rochelle, April 21, 2009-Questions such as "How to search for weird alien life?" and "Would Earth microbes survive if delivered to the surface of Mars?" are addressed in articles that are part of the collection of reports presented in the current issue of Astrobiology, a peer-reviewed journal published by Mary Ann Liebert, Inc. available free online at www.liebertpub.com/ast

David Smith, Andrew Schuerger, Mark Davidson, Stephen Pacala, Corien Bakermans, and Tullis Onstott, from Princeton University, the Kennedy Space Center, and Michigan State University, exposed a bacterium that lives in the Siberian permafrost on Earth to the harsh conditions on Mars using a Mars Simulation Chamber. Low temperature and atmospheric pressure, and high dryness and ultraviolet (UV) irradiation flux characterize the surface conditions of present day Mars. Though certain terrestrial bacteria pose a serious contamination threat to Mars, the researchers found that the bacterium tested could not survive the UV levels typically found on the martian surface. They describe their findings in the article, "Survivability of Psychrobacter cryohalolentis K5 Under Simulated Martian Surface Conditions."

Another article describes exposure of an Arctic bacterial permafrost community to simulated martian conditions, including UV irradiation equivalent to about 80 days on the surface of Mars, freeze-thaw cycles, low pressure, and comparable atmospheric gas composition. Aviaja Hansen, Lars Jensen, Tommy Kristoffersen, Karina Mikkelsen, Jonathan Merrison, Kai Finster, and Bente Lomstein, from the University of Aarhus (Denmark), show that the bacteria were better able to survive the deeper under the surface they were found, with a 2-centimeter layer of dust offering substantial protection. Biomolecules, such as bacterial DNA and proteins, were more resistant to destruction than the bacteria themselves, as documented in the article, "Effects of Long-Term Simulated Martian Conditions on a Freeze-Dried and Homogenized Bacterial Permafrost Community." One of the broader conclusions that can be drawn from this study is that persistent long-term forward contamination is unlikely as long as bacterial cells are deposited in the upper 2 cm of the martian surface dust.

"Investigators focusing on the survival potential of Earth's extremophiles on Mars provide important baseline studies relevant to planetary exploration," says Sherry L. Cady, PhD, Editor of Astrobiology and Associate Professor in the Department of Geology at Portland State University. "The potential for forward contamination during the exploration of another planetary body is a global concern of all space-faring nations."

Astrobiologists recognize that potential life forms may be very different from the types of living organisms they are used to seeing on Earth. In an article titled, "Signatures of a Shadow Biosphere," Paul Davies, Steven Benner, Carol Cleland, Charles Lineweaver, Christopher McKay, and Felisa Wolfe-Simon provide strategies for addressing this challenge based on the identification of unusual life forms that may be present today or in the past in "shadow biospheres" on Earth. The authors present a case for how the search for weird life (life as we do not know it) can begin right here on Earth. "Alternative biochemistries may escape our current efforts tailored to characterize and identify known life," says co-author Felisa Wolfe-Simon, Postdoctoral Research Fellow at the Department of Earth and Planetary Sciences, Harvard University. "If identified here on Earth, a different life form may suggest either a deep root to known biology or perhaps even a 'second genesis' of life."
-end-
Astrobiology is an authoritative peer-reviewed journal published 10 times a year in print and online. The journal provides a forum for scientists seeking to advance our understanding of life's origins, evolution, distribution, and destiny in the universe. A complete table of contents and a full text for this issue may be viewed online at www.liebertpub.com/ast

Astrobiology is the leading peer-reviewed journal in its field. To promote this developing field, the Journal has teamed up with The Astrobiology Web to highlight outstanding articles in each issue of Astrobiology. These articles are available free online at www.liebertpub.com/ast and to visitors of The Astrobiology Web at www.astrobiology.com

Mary Ann Liebert, Inc. (www.liebertpub.com) is a privately held, fully integrated media company known for establishing authoritative peer-reviewed journals in many promising areas of science and biomedical research. Its biotechnology trade magazine, Genetic Engineering & Biotechnology News (GEN), was the first in its field and is today the industry's most widely read publication worldwide. A complete list of the firm's 60 journals, books, and newsmagazines is available at www.liebertpub.com

Mary Ann Liebert, Inc. 140 Huguenot St., New Rochelle, NY 10801-5215
Phone: (914) 740-2100 (800) M-LIEBERT Fax: (914) 740-2101
www.liebertpub.com

Mary Ann Liebert, Inc./Genetic Engineering News

Related Bacteria Articles from Brightsurf:

Siblings can also differ from one another in bacteria
A research team from the University of Tübingen and the German Center for Infection Research (DZIF) is investigating how pathogens influence the immune response of their host with genetic variation.

How bacteria fertilize soya
Soya and clover have their very own fertiliser factories in their roots, where bacteria manufacture ammonium, which is crucial for plant growth.

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.

Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.

Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.

Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.

Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.

How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.

The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?

Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.

Read More: Bacteria News and Bacteria Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.