title: Identification and Characterization of Early Mission Phase Microorganisms Residing on the Mars Science Laboratory and Assessment of Their Potential to Survive Mars-like Conditions.
abstract: Planetary protection is governed by the Outer Space Treaty and includes the practice of protecting planetary bodies from contamination by Earth life. Although studies are constantly expanding our knowledge about life in extreme environments, it is still unclear what the probability is for terrestrial organisms to survive and grow on Mars. Having this knowledge is paramount to addressing whether microorganisms transported from Earth could negatively impact future space exploration. The objectives of this study were to identify cultivable microorganisms collected from the surface of the Mars Science Laboratory, to distinguish which of the cultivable microorganisms can utilize energy sources potentially available on Mars, and to determine the survival of the cultivable microorganisms upon exposure to physiological stresses present on the martian surface. Approximately 66% (237) of the 358 microorganisms identified are related to members of the Bacillus genus, although surprisingly, 22% of all isolates belong to non-spore-forming genera. A small number could grow by reduction of potential growth substrates found on Mars, such as perchlorate and sulfate, and many were resistant to desiccation and ultraviolet radiation (UVC). While most isolates either grew in media containing ≥10% NaCl or at 4°C, many grew when multiple physiological stresses were applied. The study yields details about the microorganisms that inhabit the surfaces of spacecraft after microbial reduction measures, information that will help gauge whether microorganisms from Earth pose a forward contamination risk that could impact future planetary protection policy. Key Words: Planetary protection-Spore-Bioburden-MSL-Curiosity-Contamination-Mars. Astrobiology 17, 253-265.
authors.affiliation: 1 School of Food Science, University of Idaho , Moscow, Idaho.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Smith
authors.affiliation: 2 Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California.
authors.forename: James N
authors.initials: JN
authors.lastname: Benardini
authors.affiliation: 1 School of Food Science, University of Idaho , Moscow, Idaho.
authors.forename: David
authors.initials: D
authors.lastname: Anderl
authors.affiliation: 3 Department of Biological Sciences, Idaho State University , Pocatello, Idaho.
authors.forename: Matt
authors.initials: M
authors.lastname: Ford
authors.affiliation: 1 School of Food Science, University of Idaho , Moscow, Idaho.
authors.forename: Emmaleen
authors.initials: E
authors.lastname: Wear
authors.affiliation: 1 School of Food Science, University of Idaho , Moscow, Idaho.
authors.forename: Michael
authors.initials: M
authors.lastname: Schrader
authors.affiliation: 2 Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California.
authors.forename: Wayne
authors.initials: W
authors.lastname: Schubert
authors.affiliation: 4 Department of Chemistry and Applied Biological Sciences, South Dakota School of Mines and Technology , Rapid City, South Dakota.
authors.forename: Linda
authors.initials: L
authors.lastname: DeVeaux
authors.affiliation: 1 School of Food Science, University of Idaho , Moscow, Idaho.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Paszczynski
authors.affiliation: 5 Biology Department, Colby College , Waterville, Maine.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Childers
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D001419:Bacteria / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism* / Q000528:radiation effects; D003890:Desiccation; D004583:Electrons; D005118:Extraterrestrial Environment; D007753:Laboratories; D018535:Mars; D050296:Microbial Viability / Q000187:drug effects / Q000528:radiation effects; D010545:Peroxides / Q000633:toxicity; D010802:Phylogeny; D018531:Spacecraft; D014466:Ultraviolet Rays
chemical_list: D010545:Peroxides