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Neish CD, Lorenz RD, Turtle EP, Barnes JW, Trainer MG, Stiles B, Kirk R, Hibbitts CA, Malaska MJ. Strategies for Detecting Biological Molecules on Titan. ASTROBIOLOGY 2018; 18:571-585. [PMID: 29718687 DOI: 10.1089/ast.2017.1758] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Saturn's moon Titan has all the ingredients needed to produce "life as we know it." When exposed to liquid water, organic molecules analogous to those found on Titan produce a range of biomolecules such as amino acids. Titan thus provides a natural laboratory for studying the products of prebiotic chemistry. In this work, we examine the ideal locales to search for evidence of, or progression toward, life on Titan. We determine that the best sites to identify biological molecules are deposits of impact melt on the floors of large, fresh impact craters, specifically Sinlap, Selk, and Menrva craters. We find that it is not possible to identify biomolecules on Titan through remote sensing, but rather through in situ measurements capable of identifying a wide range of biological molecules. Given the nonuniformity of impact melt exposures on the floor of a weathered impact crater, the ideal lander would be capable of precision targeting. This would allow it to identify the locations of fresh impact melt deposits, and/or sites where the melt deposits have been exposed through erosion or mass wasting. Determining the extent of prebiotic chemistry within these melt deposits would help us to understand how life could originate on a world very different from Earth. Key Words: Titan-Prebiotic chemistry-Solar system exploration-Impact processes-Volcanism. Astrobiology 18, 571-585.
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Affiliation(s)
- Catherine D Neish
- 1 Department of Earth Sciences, The University of Western Ontario , London, Canada
| | - Ralph D Lorenz
- 2 The Johns Hopkins Applied Physics Laboratory , Laurel, Maryland
| | | | - Jason W Barnes
- 3 Department of Physics, University of Idaho , Moscow, Idaho
| | | | - Bryan Stiles
- 5 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California
| | - Randolph Kirk
- 6 United States Geological Survey, Astrogeology Science Center , Flagstaff, Arizona
| | | | - Michael J Malaska
- 5 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California
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Brassé C, Buch A, Coll P, Raulin F. Low-Temperature Alkaline pH Hydrolysis of Oxygen-Free Titan Tholins: Carbonates' Impact. ASTROBIOLOGY 2017; 17:8-26. [PMID: 28103106 DOI: 10.1089/ast.2016.1524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Titan, the largest moon of Saturn, is one of the key planetary objects in the field of exobiology. Its dense, nitrogen-rich atmosphere is the site of important organic chemistry. This paper focuses on the organic aerosols produced in Titan's atmosphere that play an important role in atmospheric and surface processes and in organic chemistry as it applies to exobiological interests. To produce reliable laboratory analogues of these aerosols, we developed, tested, and optimized a device for the synthesis of clean tholins. The potential chemical evolution of Titan aerosols at Titan's surface has been studied, in particular, the possible interaction between aerosols and putative ammonia-water cryomagma. Modeling of the formation of Saturn's atmosphere has permitted the characterization of a composition of salts in the subsurface ocean and cryolava. From this new and original chemical composition, a laboratory study of several hydrolyses of tholins was carried out. The results obtained show the formation of many organic compounds, among them, species identified only in the presence of salts. In addition, a list of potential precursors of these compounds was established, which could provide a database for research of the chemical composition of tholins and/or aerosols of Titan. Key Words: Titan tholins-Titan aerosols-Hydrolysis-Carbonates-Titan's surface. Astrobiology 17, 8-26.
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Affiliation(s)
- Coralie Brassé
- 1 Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), UMR CNRS 7583, Université Paris Est Créteil et Université Paris Diderot , Institut Pierre Simon Laplace, C.M.C., Créteil, France
| | - Arnaud Buch
- 2 Laboratoire de Génie des Procédés et Matériaux (LGPM) , Ecole Centrale Paris, Chatenay-Malabry, France
| | - Patrice Coll
- 1 Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), UMR CNRS 7583, Université Paris Est Créteil et Université Paris Diderot , Institut Pierre Simon Laplace, C.M.C., Créteil, France
| | - François Raulin
- 1 Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), UMR CNRS 7583, Université Paris Est Créteil et Université Paris Diderot , Institut Pierre Simon Laplace, C.M.C., Créteil, France
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Barnes JW, Buratti BJ, Turtle EP, Bow J, Dalba PA, Perry J, Brown RH, Rodriguez S, Mouélic SL, Baines KH, Sotin C, Lorenz RD, Malaska MJ, McCord TB, Clark RN, Jaumann R, Hayne PO, Nicholson PD, Soderblom JM, Soderblom LA. Precipitation-induced surface brightenings seen on Titan by Cassini VIMS and ISS. ACTA ACUST UNITED AC 2013. [DOI: 10.1186/2191-2521-2-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Clark RN, Curchin JM, Barnes JW, Jaumann R, Soderblom L, Cruikshank DP, Brown RH, Rodriguez S, Lunine J, Stephan K, Hoefen TM, Le Mouélic S, Sotin C, Baines KH, Buratti BJ, Nicholson PD. Detection and mapping of hydrocarbon deposits on Titan. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009je003369] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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RNA processing pathways in amyotrophic lateral sclerosis. Neurogenetics 2010; 11:275-90. [PMID: 20349096 DOI: 10.1007/s10048-010-0239-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 02/24/2010] [Indexed: 12/12/2022]
Abstract
RNA processing is a tightly regulated, highly complex pathway which includes RNA transcription, pre-mRNA splicing, editing, transportation, translation, and degradation of RNA. Over the past few years, several RNA processing genes have been shown to be mutated or genetically associated with amyotrophic lateral sclerosis (ALS), including the RNA-binding proteins TDP-43 and FUS/TLS. These findings suggest that RNA processing may represent a common pathogenic mechanism involved in development of ALS. In this review, we will discuss six ALS-related, RNA processing genes including their discovery, function, and commonalities.
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Abstract
Methane clouds, lakes and most fluvial features on Saturn's moon Titan have been observed in the moist high latitudes, while the tropics have been nearly devoid of convective clouds and have shown an abundance of wind-carved surface features like dunes. The presence of small-scale channels and dry riverbeds near the equator observed by the Huygens probe at latitudes thought incapable of supporting convection (and thus strong rain) has been suggested to be due to geological seepage or other mechanisms not related to precipitation. Here we report the presence of bright, transient, tropospheric clouds in tropical latitudes. We find that the initial pulse of cloud activity generated planetary waves that instigated cloud activity at other latitudes across Titan that had been cloud-free for at least several years. These observations show that convective pulses at one latitude can trigger short-term convection at other latitudes, even those not generally considered capable of supporting convection, and may also explain the presence of methane-carved rivers and channels near the Huygens landing site.
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Global circulation as the main source of cloud activity on Titan. Nature 2009; 459:678-82. [DOI: 10.1038/nature08014] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Accepted: 03/23/2009] [Indexed: 11/08/2022]
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The identification of liquid ethane in Titan's Ontario Lacus. Nature 2008; 454:607-10. [PMID: 18668101 DOI: 10.1038/nature07100] [Citation(s) in RCA: 224] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Accepted: 05/19/2008] [Indexed: 11/08/2022]
Abstract
Titan was once thought to have global oceans of light hydrocarbons on its surface, but after 40 close flybys of Titan by the Cassini spacecraft, it has become clear that no such oceans exist. There are, however, features similar to terrestrial lakes and seas, and widespread evidence for fluvial erosion, presumably driven by precipitation of liquid methane from Titan's dense, nitrogen-dominated atmosphere. Here we report infrared spectroscopic data, obtained by the Visual and Infrared Mapping Spectrometer (VIMS) on board the Cassini spacecraft, that strongly indicate that ethane, probably in liquid solution with methane, nitrogen and other low-molecular-mass hydrocarbons, is contained within Titan's Ontario Lacus.
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Le Mouélic S, Paillou P, Janssen MA, Barnes JW, Rodriguez S, Sotin C, Brown RH, Baines KH, Buratti BJ, Clark RN, Crapeau M, Encrenaz PJ, Jaumann R, Geudtner D, Paganelli F, Soderblom L, Tobie G, Wall S. Mapping and interpretation of Sinlap crater on Titan using Cassini VIMS and RADAR data. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007je002965] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Barnes JW, Radebaugh J, Brown RH, Wall S, Soderblom L, Lunine J, Burr D, Sotin C, Le Mouélic S, Rodriguez S, Buratti BJ, Clark R, Baines KH, Jaumann R, Nicholson PD, Kirk RL, Lopes R, Lorenz RD, Mitchell K, Wood CA. Near-infrared spectral mapping of Titan's mountains and channels. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2007je002932] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Negrão A, Hirtzig M, Coustenis A, Gendron E, Drossart P, Rannou P, Combes M, Boudon V. The 2-μm spectroscopy of Huygens probe landing site on Titan with Very Large Telescope/Nasmyth Adaptive Optics System Near-Infrared Imager and Spectrograph. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2005je002651] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Tokano T, Ferri F, Colombatti G, Mäkinen T, Fulchignoni M. Titan's planetary boundary layer structure at the Huygens landing site. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2006je002704] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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