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Potassium ferrate [Fe(VI)] does not mediate self-sterilization of a surrogate mars soil

BACKGROUND: Martian soil is thought to be enriched with strong oxidants such as peroxides and/or iron in high oxidation states that might destroy biological materials. There is also a high flux of ultraviolet radiation at the surface of Mars. Thus, Mars may be inhospitable to life as we know it on E...

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Autores principales: Crawford, Ronald L, Paszczynski, Andrzej, Allenbach, Lisa
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2003
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC153549/
https://www.ncbi.nlm.nih.gov/pubmed/12694634
http://dx.doi.org/10.1186/1471-2180-3-4
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author Crawford, Ronald L
Paszczynski, Andrzej
Allenbach, Lisa
author_facet Crawford, Ronald L
Paszczynski, Andrzej
Allenbach, Lisa
author_sort Crawford, Ronald L
collection PubMed
description BACKGROUND: Martian soil is thought to be enriched with strong oxidants such as peroxides and/or iron in high oxidation states that might destroy biological materials. There is also a high flux of ultraviolet radiation at the surface of Mars. Thus, Mars may be inhospitable to life as we know it on Earth. We examined the hypothesis that if the soil of Mars contains ferrates [Fe(VI)], the strongest of the proposed oxidizing species, and also is exposed to high fluxes of UV radiation, it will be self-sterilizing. RESULTS: Under ambient conditions (25°C, oxygen and water present) K(2)FeO(4 )mixed into sand mineralized some reactive organic molecules to CO(2), while less reactive compounds were not degraded. Dried endospores of Bacillus subtilis incubated in a Mars surrogate soil comprised of dry silica sand containing 20% by weight K(2)FeO(4 )and under conditions similar to those now on Mars (extreme desiccation, cold, and a CO(2)-dominated atmosphere) were resistant to killing by the ferrate-enriched sand. Similar results were observed with permanganate. Spores in oxidant-enriched sand exposed to high fluxes of UV light were protected from the sporocidal activity of the radiation below about 5 mm depths. CONCLUSION: Based on our data and previously published descriptions of ancient but dormant life forms on Earth, we suggest that if entities resembling bacterial endospores were produced at some point by life forms on Mars, they might still be present and viable, given appropriate germination conditions. Endospores delivered to Mars on spacecraft would possibly survive and potentially compromise life detection experiments.
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spelling pubmed-1535492003-04-19 Potassium ferrate [Fe(VI)] does not mediate self-sterilization of a surrogate mars soil Crawford, Ronald L Paszczynski, Andrzej Allenbach, Lisa BMC Microbiol Research Article BACKGROUND: Martian soil is thought to be enriched with strong oxidants such as peroxides and/or iron in high oxidation states that might destroy biological materials. There is also a high flux of ultraviolet radiation at the surface of Mars. Thus, Mars may be inhospitable to life as we know it on Earth. We examined the hypothesis that if the soil of Mars contains ferrates [Fe(VI)], the strongest of the proposed oxidizing species, and also is exposed to high fluxes of UV radiation, it will be self-sterilizing. RESULTS: Under ambient conditions (25°C, oxygen and water present) K(2)FeO(4 )mixed into sand mineralized some reactive organic molecules to CO(2), while less reactive compounds were not degraded. Dried endospores of Bacillus subtilis incubated in a Mars surrogate soil comprised of dry silica sand containing 20% by weight K(2)FeO(4 )and under conditions similar to those now on Mars (extreme desiccation, cold, and a CO(2)-dominated atmosphere) were resistant to killing by the ferrate-enriched sand. Similar results were observed with permanganate. Spores in oxidant-enriched sand exposed to high fluxes of UV light were protected from the sporocidal activity of the radiation below about 5 mm depths. CONCLUSION: Based on our data and previously published descriptions of ancient but dormant life forms on Earth, we suggest that if entities resembling bacterial endospores were produced at some point by life forms on Mars, they might still be present and viable, given appropriate germination conditions. Endospores delivered to Mars on spacecraft would possibly survive and potentially compromise life detection experiments. BioMed Central 2003-03-06 /pmc/articles/PMC153549/ /pubmed/12694634 http://dx.doi.org/10.1186/1471-2180-3-4 Text en Copyright © 2003 Crawford et al; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.
spellingShingle Research Article
Crawford, Ronald L
Paszczynski, Andrzej
Allenbach, Lisa
Potassium ferrate [Fe(VI)] does not mediate self-sterilization of a surrogate mars soil
title Potassium ferrate [Fe(VI)] does not mediate self-sterilization of a surrogate mars soil
title_full Potassium ferrate [Fe(VI)] does not mediate self-sterilization of a surrogate mars soil
title_fullStr Potassium ferrate [Fe(VI)] does not mediate self-sterilization of a surrogate mars soil
title_full_unstemmed Potassium ferrate [Fe(VI)] does not mediate self-sterilization of a surrogate mars soil
title_short Potassium ferrate [Fe(VI)] does not mediate self-sterilization of a surrogate mars soil
title_sort potassium ferrate [fe(vi)] does not mediate self-sterilization of a surrogate mars soil
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC153549/
https://www.ncbi.nlm.nih.gov/pubmed/12694634
http://dx.doi.org/10.1186/1471-2180-3-4
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