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Published May 2021 | Supplemental Material + Published
Journal Article Open

Detection and Degradation of Adenosine Monophosphate in Perchlorate-Spiked Martian Regolith Analogue, by Deep-Ultraviolet Spectroscopy

Abstract

The search for organic biosignatures on Mars will depend on finding material protected from the destructive ambient radiation. Solar ultraviolet can induce photochemical degradation of organic compounds, but certain clays have been shown to preserve organic material. We examine how the SHERLOC instrument on the upcoming Mars 2020 mission will use deep-ultraviolet (UV) (248.6 nm) Raman and fluorescence spectroscopy to detect a plausible biosignature of adenosine 5′-monophosphate (AMP) adsorbed onto Ca-montmorillonite clay. We found that the spectral signature of AMP is not altered by adsorption in the clay matrix but does change with prolonged exposure to the UV laser over dosages equivalent to 0.2–6 sols of ambient martian UV. For pure AMP, UV exposure leads to breaking of the aromatic adenine unit, but in the presence of clay the degradation is limited to minor alteration with new Raman peaks and increased fluorescence consistent with formation of 2-hydroxyadenosine, while 1 wt % Mg perchlorate increases the rate of degradation. Our results confirm that clays are effective preservers of organic material and should be considered high-value targets, but that pristine biosignatures may be altered within 1 sol of martian UV exposure, with implications for Mars 2020 science operations and sample caching.

Additional Information

© 2021, Mary Ann Liebert, Inc., publishers. The work described in this article was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. No competing financial interests exist. This work was funded by a NASA Postdoctoral Program Fellowship awarded to Joseph Razzell Hollis, administered by the Universities Space Research Association on behalf of NASA, and Teresa Fornaro was supported by the Geophysical Laboratory of the Carnegie Institution of Washington and the Italian Space Agency (ASI) grant agreement ExoMars number 2017-48-H.0. William Rapin was funded by an MSL-Curiosity Participating Scientist grant to Bethany Ehlmann. © 2019. California Institute of Technology; government sponsorship acknowledged.

Attached Files

Published - ast.2020.2362.pdf

Supplemental Material - Supp_FigureS1.docx

Supplemental Material - Supp_FigureS2.docx

Supplemental Material - Supp_FigureS3.docx

Supplemental Material - Supp_FigureS4.docx

Supplemental Material - Supp_FigureS5.docx

Supplemental Material - Supp_FigureS6.docx

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Additional details

Created:
August 20, 2023
Modified:
October 23, 2023