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Effects of a Simulated Martian UV Flux on the Cyanobacterium, Chroococcidiopsis sp. 029

Cockell, Ch. and Schuerger, A.C. and Billi, D. and Friedmann, E. and Panitz, Corinna (2005) Effects of a Simulated Martian UV Flux on the Cyanobacterium, Chroococcidiopsis sp. 029. Astrobiology, 5 (2), pp. 127-140. Mary Ann Liebert, Inc..

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Abstract

Dried monolayers of Chroococcidiopsis sp. 029, a desiccation-tolerant, endolithic cyanobacterium, were exposed to a simulated martian-surface UV and visible light flux, which may also approximate to the worst-case scenario for the Archean Earth. After 5 min, there was a 99% loss of cell viability, and there were no survivors after 30 min. However, this survival was approximately 10 times higher than that previously reported for Bacillus subtilis. We show that under 1 mm of rock, Chroococcidiopsis sp. could survive (and potentially grow) under the high martian UV flux if water and nutrient requirements for growth were met. In isolated cells, phycobilisomes and esterases remained intact hours after viability was lost. Esterase activity was reduced by 99% after a l-h exposure, while 99% loss of autofluorescence required a 4-h exposure. However, cell morphology was not changed, and DNA was still detectable by 4',6-diamidino-2-phenylindole staining after an 8-h exposure (equivalent to approximately 1 day on Mars at the equator). Under 1 mm of simulant martian soil or gneiss, the effect of UV radiation could not be detected on esterase activity or autofluorescence after 4 h. These results show that under the intense martian UV flux the morphological signatures of life can persist even after viability, enzymatic activity, and pigmentation have been destroyed. Finally, the global dispersal of viable, isolated cells of even this desiccation-tolerant, ionizing-radiation-resistant microorganism on Mars is unlikely as they are killed quickly by unattenuated UV radiation when in a desiccated state. These findings have implications for the survival of diverse microbial contaminants dispersed during the course of human exploratory class missions on the surface of Mars

Item URL in elib:https://elib.dlr.de/47911/
Document Type:Article
Title:Effects of a Simulated Martian UV Flux on the Cyanobacterium, Chroococcidiopsis sp. 029
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Cockell, Ch.British Antarctic Survey, Cambridge, United KingdomUNSPECIFIED
Schuerger, A.C.Department of Plant Pathology, University of Florida, Space Life Sciences Laboratory, Kennedy Space Center,UNSPECIFIED
Billi, D.Department of Biology, University of Rome "Tor Vergata," Rome, ItalyUNSPECIFIED
Friedmann, E.NASA Ames Research Center, Moffett Field, California.UNSPECIFIED
Panitz, CorinnaUNSPECIFIEDUNSPECIFIED
Date:2005
Journal or Publication Title:Astrobiology
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:Yes
Volume:5
Page Range:pp. 127-140
Publisher:Mary Ann Liebert, Inc.
Status:Published
Keywords:Ultraviolet Radiation, Mars, Simulated Martian UV Flux, Cyanobacterium, Chroococcidiopsis sp. 029
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W FR - Forschung unter Weltraumbedingungen (old)
DLR - Research area:Space
DLR - Program:W FR - Forschung unter Weltraumbedingungen
DLR - Research theme (Project):W - Vorhaben Strahlenbiologie (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Aerospace Medicine > Radiation Biology
Deposited By: Kopp, Kerstin
Deposited On:08 May 2007
Last Modified:27 Apr 2009 13:38

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