2002-2003 Colloquium Series
NAU Physical Sciences (Bldg 19, Rm 321), Friday, 7 February 2003, 4:00 PM
(Refreshments at 3:45 PM)
ASTROBIOLOGY GOLLOQUIUM
Are There Halophilic (Salt-Loving) Microorganisms on Mars?
Richard Shand , Northern Arizona University
Abstract
The Martian surface appears to be replete with Na+ and Mg++ ions.
When mixed with water, these two ions are the major constituents of
most hypersaline environments on Earth. In addition, carbon dioxide
is in abundance on Mars, and so a carbon source is available.
Evidence is growing that Mars had liquid water on its surface
sometime in the past, and may well have had a hypersaline
environment. Hypersaline environments may be present today on Mars if
there is liquid water below the Martian surface that is continually
leaching ions from the surrounding rock. However, evidence for
subsurface liquid water on Mars is scarce; the water appears to be
frozen. Extremely halophilic (salt-loving) microorganisms have been
resuscitated from fluid inclusions inside halite (geologically
deposited NaCl) that has been dated to 250 million years. This time
frame encompasses the period when water may have been on the Martian
surface. If halophilic microorganisms evolved on Mars, they may have
been trapped inside salt crystals and preserved as the Martian
surface dried up. If we are to have any luck in resuscitating such
organisms, it will be essential to develop efficient resuscitation
protocols using terrestrial halite and salt deposits as models.
Dr. Richard Shand is a Professor of Microbiology in the Department of
Biological Sciences at Northern Arizona University. After earning his
BS in Biological Sciences, he was a Peace Corps Volunteer in Western
Samoa where he was a secondary education teacher in a village school.
Upon his return from the Peace Corps, he received his M.S. degree in
Microbiology for California State University, Long Beach. He received
his PhD in Microbiology from the University of California at Davis,
and then was an NIH post-doctoral fellow at the University of
California at San Francisco. He joined the Biological Sciences
faculty at NAU in 1990. He uses extremely halophilic members of the
domain Archaea (salt-loving microbes; the "haloarchaea") as model
systems in his research. His research encompasses regulation of
stationary phase gene expression of halocin genes, secretion and
mechanism of action of halocin proteins (i.e., protein antibiotics
produced by extreme halophiles, protein structure/function studies of
halocins, bioinformatics of megaplasmids from the haloarchaea, and
development of efficient protocols for the resuscitation of extreme
halophiles from halite (geologically deposited NaCl), salt rocks and
surface salt deposits. More information can be found at
http://jan.ucc.nau.edu/~shand.
Local Host: Dave Koerner, (928) 523-4562.