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Lessons from Astrobiological Planetary Analogue Exploration in Iceland: Biomarker Assay Performance and DownselectionUnderstanding the sensitivity of biomarker assays to the local physicochemical environment, and the underlying spatial distribution of the target biomarkers in 'homogeneous' environments, can increase mission science return. We have conducted four expeditions to Icelandic Mars analogue sites in which an increasingly refined battery of physicochemical measurements and biomarker assays were performed, staggered with scouting of further sites. Completed expeditions took place in 2012 (location scouting and field assay use testing), 2013 (sampling of two major sites with three assays and observational physicochemical measurements), 2015 (repeat sampling of prior sites and one new site, scouting of new sites, three assays and three instruments), and 2016 (preliminary sampling of new sites with analysis of returned samples). Target sites were geologically recent basaltic lava flows, and sample loci were arranged in hierarchically nested grids at 10 cm, 1 m, 10 m, 100 m, and >1 km order scales, subject to field constraints. Assays were intended to represent a diversity of potential biomarker types (cell counting via nucleic acid staining and fluorescence microscopy, ATP quantification via luciferase luminescence, and relative DNA quantification with simple domain-level primers) rather a specific mission science target, and were selected to reduce laboratory overhead, require limited consumables, and allow rapid turnaround. All analytical work was performed in situ or in a field laboratory within a day's travel of the field sites unless otherwise noted. We have demonstrated the feasibility of performing ATP quantification and qPCR analysis in a field-based laboratory with single-day turnaround. The ATP assay was generally robust and reliable and required minimal field equipment and training to produce a large amount of useful data. DNA was successfully extracted from all samples, but the serial-batch nature of qPCR significantly limited the number of primers (hence classifications) and replicates that could be run in a single day. Fluorescence microscopy did not prove feasible under the same constraints, primarily due to the large number of person-hours required to view, analyze, and record results from the images; however, this could be mitigated with higher-quality imaging instruments and appropriate image analysis software.
Document ID
20170002413
Document Type
Conference Paper
Authors
Gentry, D. M. (NASA Ames Research Center Moffett Field, CA United States)
Amador, E. S. (Washington Univ. Seattle, WA, United States)
Cable, M. L. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Cantrell, T. (Georgia Inst. of Tech. Atlanta, GA, United States)
Chaudry, N. (Cranfield Univ. Cranfield, United Kingdom)
Cullen, T. (Cranfield Univ. Cranfield, United Kingdom)
Duca, Z. (Georgia Inst. of Tech. Atlanta, GA, United States)
Kirby, J. (Cranfield Univ. Cranfield, United Kingdom)
Jacobsen, M.
McCaig, H. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Murukesan, G. (Turku Univ. Finland)
Rennie, V. (Edinburgh Univ. United Kingdom)
Schwieterman, E. (Washington Univ. Seattle, WA, United States)
Stevens, (Edinburgh Univ. United Kingdom)
Tan, G. (Georgia Inst. of Tech. Atlanta, GA, United States)
Yin, C. (Stockholm Univ. Sweden)
Stockton, A. (Georgia Inst. of Tech. Atlanta, GA, United States)
Cullen, D. (Cranfield Univ. Cranfield, United Kingdom)
Geppert, W. (Stockholm Univ. Sweden)
Date Acquired
March 23, 2017
Publication Date
March 20, 2017
Subject Category
Exobiology
Earth Resources and Remote Sensing
Report/Patent Number
ARC-E-DAA-TN39489
Meeting Information
Lunar and Planetary Science Conference)(The Woodlands, TX)
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Planetary
Exploration
Performance

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