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Abstracts
1/25/06
Astrobiology, Astrochemistry and the AstroBiology Explorer (ABE)
Kimberly Ennico
NASA Ames Research Center
I will give a brief overview of NASA Ames Research Center,
Astrobiology and NASA, with emphasis on the strong astrobiology
(particularly astrochemistry) science drivers behind the AstroBiology
Explorer (ABE) MIDEX Mission Concept.
Astrobiology is a interdisciplinary field geared to answer the questions of
(1) How does life begin & develop? (2) Does life exist elsewhere in the
Universe? and (3) What is life's future on Earth and beyond? Researchers in
the related field of Astrochemistry investigate the evolution of
materials from dying stars to interstellar organic compounds and molecules
from which life evolves. This talk will highlight some of the research by
members of the Ames Astrochemistry Lab and how it may relate to the field of
Astrobiology. My work, which has been in the development and maturation of the
AstroBiology Explorer (ABE) Mission Concept will be highlighted at the end.
1/25/06
Radiation-Driven Growth of Deinococcus radiodurans: Astrobiological
Implications
Michael J. Daly
Dept. of Pathology
F.E. Herbert School of Medicine
Bethesda, MD
Recent reports suggest that a substantial number of subsurface microbes on Earth
might be surviving solely by consuming a product of feeble radioactive decay lingering
from before Earth's formation (Science 312, 14 APRIL 2006, p. 179). Such microbes may
point the way to creatures that live entirely "off the grid," independent of the energy the
sun supplies by means of photosynthesis. Extreme ionizing radiation (IR) resistance in
the bacterium Deinococcus radiodurans is dependent on high intracellular concentrations
of Mn(II). In vitro in the presence of IR, Mn(II,III) redox-cycling favors superoxide scavenging
with intermediate release of hydrogen peroxide. In vivo, D. radiodurans exhibited physiological
characteristics consistent with IR-driven Mn redox-cycling processes. We establish the
feasibility of IR-driven microbial ecosystems by showing that IR in anaerobic culture
conditions induces growth of the strictly aerobic D. radiodurans.
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