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Effect of shadowing on survival of bacteria under conditions simulating the Martian atmosphere and UV radiation

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dc.contributor.author Osman, Shariff
dc.contributor.author Peeters, Zan
dc.contributor.author La Duc, Myron T.
dc.contributor.author Mancinelli, Rocco
dc.contributor.author Ehrenfreund, Pascale
dc.contributor.author Venkateswaran, Kasthuri
dc.date.accessioned 2008-08-07T22:52:44Z
dc.date.available 2008-08-07T22:52:44Z
dc.date.issued 2008-02
dc.identifier.citation Applied and Environmental Microbiology, Vol. 74, No. 4, Feb. 2008, p. 959–970 en_US
dc.identifier.clearanceno 07-2299
dc.identifier.uri http://hdl.handle.net/2014/40903
dc.description.abstract Spacecraft-associated spores and four non-spore-forming bacterial isolates were prepared in Atacama Desert soil suspensions and tested both in solution and in a desiccated state to elucidate the shadowing effect of soil particulates on bacterial survival under simulated Martian atmospheric and UV irradiation conditions. All non-spore-forming cells that were prepared in nutrient-depleted, 0.2-μm-filtered desert soil (DSE) microcosms and desiccated for 75 days on aluminum died, whereas cells prepared similarly in 60-μm-filtered desert soil (DS) microcosms survived such conditions. Among the bacterial cells tested, Microbacterium schleiferi and Arthrobacter sp. exhibited elevated resistance to 254-nm UV irradiation (low-pressure Hg lamp), and their survival indices were comparable to those of DS- and DSE-associated Bacillus pumilus spores. Desiccated DSE-associated spores survived exposure to full Martian UV irradiation (200 to 400 nm) for 5 min and were only slightly affected by Martian atmospheric conditions in the absence of UV irradiation. Although prolonged UV irradiation (5 min to 12 h) killed substantial portions of the spores in DSE microcosms (~5- to 6-log reduction with Martian UV irradiation), dramatic survival of spores was apparent in DS-spore microcosms. The survival of soil-associated wild-type spores under Martian conditions could have repercussions for forward contamination of extraterrestrial environments, especially Mars. en_US
dc.description.sponsorship NASA/JPL en_US
dc.language.iso en_US en_US
dc.publisher American Society for Microbiology en_US
dc.subject Atacama Desert en_US
dc.subject soil suspensions en_US
dc.subject Martian atmosphere en_US
dc.subject bacteria
dc.subject survival
dc.subject forward contamination
dc.title Effect of shadowing on survival of bacteria under conditions simulating the Martian atmosphere and UV radiation en_US
dc.type Article en_US


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