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Petra Rettberg, André Antunes, John Brucato, Patricia Cabezas, Geoffrey Collins, Alissa Haddaji, Gerhard Kminek, Stefan Leuko, Susan McKenna-Lawlor, Christine Moissl-Eichinger, Jean-Louis Fellous, Karen Olsson-Francis, David Pearce, Elke Rabbow, Samuel Royle, Mark Saunders, Mark Sephton, Andy Spry, Nicolas Walter, Robert Wimmer Schweingruber, Jean-Charles Treuet
To ensure that scientific investments in space exploration are not compromised by terrestrial contamination of celestial bodies, special care needs to be taken to preserve planetary conditions for future astrobiological exploration. Significant effort has been made and is being taken to address planetary protection in the context of inner Solar System exploration. In particular for missions to Mars, detailed internationally accepted guidelines have been established. For missions to the icy moons in the outer Solar System, Europa and Enceladus, the planetary protection requirements are so far based on a probabilistic approach and a conservative estimate of poorly known parameters...
February 14, 2019: Astrobiology
Daniela Billi, Clelia Staibano, Cyprien Verseux, Claudia Fagliarone, Claudia Mosca, Mickael Baqué, Elke Rabbow, Petra Rettberg
Dried biofilms and dried multilayered planktonic counterparts obtained from three desert strains of Chroococcidiopsis were exposed to low Earth conditions by using the EXPOSE-R2 facility outside the International Space Station. During the space mission, samples in Tray 1 (space vacuum and solar radiation, from λ ≈ 110 nm) and Tray 2 (Mars-like UV flux, λ > 200 nm and Mars-like atmosphere) received total UV (200-400 nm) fluences of about 4.58 × 102 kJ/m2 and 4.92 × 102 kJ/m2 , respectively, and 0...
February 11, 2019: Astrobiology
David Ross, David Deamer
Polymerization of nucleotides and amino acids to form large, complex, and potentially functional products was an early and essential event on the paths leading to life's origin. The standard Gibbs energies of the condensation reactions are uphill, however, and at equilibrium will yield only declining sequences of small, nonfunctional oligomers. Geochemically produced condensing agents such as carbonyl sulfide, cyanamide, and polyphosphates have been proposed to invert the unfavorable condensation Gibbs energies and thereby activate exergonic condensation...
February 1, 2019: Astrobiology
Rowena Ball, John Brindley
The hydrogen peroxide (HP) crucible hypothesis proposed here holds that life began in a localized environment on Earth that was perfused with a flow of hydrogen peroxide from a sustained external source, which powered and mediated molecular evolution and the protocellular RNA world. In this article, we consolidate and review recent evidence, both circumstantial and tested in simulation in our work and in the laboratory in others' work, for its multiple roles in the evolution of the first living systems: (1) it provides a periodic power source as the thiosulfate-hydrogen peroxide (THP) redox oscillator, (2) it may act as an agent of molecular change and evolution and mediator of homochirality, and (3) the THP oscillator, subject to Brownian input perturbations, produces a weighted distribution of output thermal fluctuations that favor polymerization and chemical diversification over chemical degradation and simplification...
February 1, 2019: Astrobiology
Hyo-Joong Kim, Justin Kim
The "RNA first" model for the origin of life holds that RNA emerged spontaneously on early Earth and developed into life through its dual capabilities for genetics and catalysis. The model's central weakness is the difficulty of making its building blocks, in particular, the glycosidic bond joining nucleobases to ribose. Thus, the focus of much of the modern literature on the topic is directed toward solving this difficulty and includes elegant, though indirect, methods for making this bond. Here, we report that the glycosidic bond in canonical pyrimidine and purine ribonucleotides can be formed by direct coupling of cyclic carbohydrate phosphates with free nucleobases, all reported to be available by experimentally supported pathways that might have operated on early Earth...
January 30, 2019: Astrobiology
John D Rummel
This paper treats the very specific history of one aspect of space policy and how it, or more specifically its name, developed in the first two decades of the Space Age. The concepts of preventing the biological and organic contamination of other planetary bodies, which also protect the biosphere from the consequences of finding extraterrestrial life and returning it to Earth, were established in the late 1950s with the beginning of the Space Age. Within their first decade, those concepts were labeled "planetary quarantine," a name that suggested the concepts but unfortunately came with latent baggage of its own...
January 29, 2019: Astrobiology
G A Baratta, M Accolla, D Chaput, H Cottin, M E Palumbo, G Strazzulla
We describe the results obtained on a set of organic samples that have been part of the experiment "Photochemistry on the Space Station (PSS)" on the EXPOSE-R2 mission conducted on the EXPOSE-R facility situated outside the International Space Station (ISS). The organic samples were prepared in the Catania laboratory by 200 keV He+ irradiation of N2 :CH4 :CO icy mixtures deposited at 17 K, on vacuum UV (VUV) transparent MgF2 windows. This organic material contains different chemical groups, including triple CN bonds, that are thought to be of interest for astrobiology...
January 17, 2019: Astrobiology
B Cavalazzi, R Barbieri, F Gómez, B Capaccioni, K Olsson-Francis, M Pondrelli, A P Rossi, K Hickman-Lewis, A Agangi, G Gasparotto, M Glamoclija, G G Ori, N Rodriguez, M Hagos
The Dallol volcano and its associated hydrothermal field are located in a remote area of the northern Danakil Depression in Ethiopia, a region only recently appraised after decades of inaccessibility due to severe political instability and the absence of infrastructure. The region is notable for hosting environments at the very edge of natural physical-chemical extremities. It is surrounded by a wide, hyperarid salt plain and is one of the hottest (average annual temperatureDallol : 36-38°C) and most acidic natural system (pHDallol ≈0) on Earth...
January 17, 2019: Astrobiology
J Kawai, D Chris McLendon, H-J Kim, S A Benner
While formaldehyde (HCHO) was likely generated in Earth's prebiotic atmosphere by ultraviolet light, electrical discharge, and/or volcano-created lightning, HCHO could not have accumulated in substantial amounts in prebiotic environments, including those needed for prebiotic processes that generate nucleosidic carbohydrates. HCHO at high concentrations in alkaline solutions self-reacts in the Cannizzaro reaction to give methanol and formate, neither having prebiotic value. Here, we explore the possibility that volcanic sulfur dioxide (SO2 ) might have generated a reservoir for Hadean HCHO by a reversible reaction with HCHO to give hydroxymethanesulfonate (HMS)...
January 7, 2019: Astrobiology
Manasvi Lingam, Abraham Loeb
We estimate the relative likelihood of success in the searches for primitive versus intelligent life on other planets. Taking into account the larger search volume for detectable artificial electromagnetic signals, we conclude that both searches should be performed concurrently, albeit with significantly more funding dedicated to primitive life. Based on the current federal funding allocated to the search for biosignatures, our analysis suggests that the search for extraterrestrial intelligence (SETI) may merit a federal funding level of at least $10 million per year, assuming that the average lifetime of technological species exceeds a millennium...
December 15, 2018: Astrobiology
Olga Podolich, Olga Kukharenko, Andriy Haidak, Iryna Zaets, Leonid Zaika, Olha Storozhuk, Larysa Palchikovska, Iryna Orlovska, Oleg Reva, Tatiana Borisova, Ludmila Khirunenko, Mikhail Sosnin, Elke Rabbow, Volodymyr Kravchenko, Mykola Skoryk, Maksym Kremenskoy, Rene Demets, Karen Olsson-Francis, Natalia Kozyrovska, Jean-Pierre Paul de Vera
A kombucha multimicrobial culture (KMC) was exposed to simulated Mars-like conditions in low-Earth orbit (LEO). The study was part of the Biology and Mars Experiment (BIOMEX), which was accommodated in the European Space Agency's EXPOSE-R2 facility, outside the International Space Station. The aim of the study was to investigate the capability of a KMC microecosystem to survive simulated Mars-like conditions in LEO. During the 18-month exposure period, desiccated KMC samples, represented by living cellulose-based films, were subjected to simulated anoxic Mars-like conditions and ultraviolet (UV) radiation, as prevalent at the surface of present-day Mars...
November 28, 2018: Astrobiology
Adrian L Melott, Franciole Marinho, Laura Paulucci
Considerable data and analysis support the detection of one or more supernovae (SNe) at a distance of about 50 pc, ∼2.6 million years ago. This is possibly related to the extinction event around that time and is a member of a series of explosions that formed the Local Bubble in the interstellar medium. We build on previous work, and propagate the muon flux from SN-initiated cosmic rays from the surface to the depths of the ocean. We find that the radiation dose from the muons will exceed the total present surface dose from all sources at depths up to 1 km and will persist for at least the lifetime of marine megafauna...
November 27, 2018: Astrobiology
Björn Huwe, Annelie Fiedler, Sophie Moritz, Elke Rabbow, Jean Pierre de Vera, Jasmin Joshi
As a part of the European Space Agency mission "EXPOSE-R2" on the International Space Station (ISS), the BIOMEX (Biology and Mars Experiment) experiment investigates the habitability of Mars and the limits of life. In preparation for the mission, experimental verification tests and scientific verification tests simulating different combinations of abiotic space- and Mars-like conditions were performed to analyze the resistance of a range of model organisms. The simulated abiotic space- and Mars-stressors were extreme temperatures, vacuum, and Mars-like surface ultraviolet (UV) irradiation in different atmospheres...
February 2019: Astrobiology
Paloma Serrano, Mashal Alawi, Jean-Pierre de Vera, Dirk Wagner
Numerous preflight investigations were necessary prior to the exposure experiment BIOMEX on the International Space Station to test the basic potential of selected microorganisms to resist or even to be active under Mars-like conditions. In this study, methanogenic archaea, which are anaerobic chemolithotrophic microorganisms whose lifestyle would allow metabolism under the conditions on early and recent Mars, were analyzed. Some strains from Siberian permafrost environments have shown a particular resistance...
February 2019: Astrobiology
Daniela Billi, Cyprien Verseux, Claudia Fagliarone, Alessandro Napoli, Mickael Baqué, Jean-Pierre de Vera
In the ESA space experiment BIOMEX (BIOlogy and Mars EXperiment), dried Chroococcidiopsis cells were exposed to Mars-like conditions during the EXPOSE-R2 mission on the International Space Station. The samples were exposed to UV radiation for 469 days and to a Mars-like atmosphere for 722 days, approaching the conditions that could be faced on the surface of Mars. Once back on Earth, cell survival was tested by growth-dependent assays, while confocal laser scanning microscopy and PCR-based assay were used to analyze the accumulated damage in photosynthetic pigments (chlorophyll a and phycobiliproteins) and genomic DNA, respectively...
February 2019: Astrobiology
Jean-Pierre de Vera, Mashal Alawi, Theresa Backhaus, Mickael Baqué, Daniela Billi, Ute Böttger, Thomas Berger, Maria Bohmeier, Charles Cockell, René Demets, Rosa de la Torre Noetzel, Howell Edwards, Andreas Elsaesser, Claudia Fagliarone, Annelie Fiedler, Bernard Foing, Frédéric Foucher, Jörg Fritz, Franziska Hanke, Thomas Herzog, Gerda Horneck, Heinz-Wilhelm Hübers, Björn Huwe, Jasmin Joshi, Natalia Kozyrovska, Martha Kruchten, Peter Lasch, Natuschka Lee, Stefan Leuko, Thomas Leya, Andreas Lorek, Jesús Martínez-Frías, Joachim Meessen, Sophie Moritz, Ralf Moeller, Karen Olsson-Francis, Silvano Onofri, Sieglinde Ott, Claudia Pacelli, Olga Podolich, Elke Rabbow, Günther Reitz, Petra Rettberg, Oleg Reva, Lynn Rothschild, Leo Garcia Sancho, Dirk Schulze-Makuch, Laura Selbmann, Paloma Serrano, Ulrich Szewzyk, Cyprien Verseux, Jennifer Wadsworth, Dirk Wagner, Frances Westall, David Wolter, Laura Zucconi
BIOMEX (BIOlogy and Mars EXperiment) is an ESA/Roscosmos space exposure experiment housed within the exposure facility EXPOSE-R2 outside the Zvezda module on the International Space Station (ISS). The design of the multiuser facility supports-among others-the BIOMEX investigations into the stability and level of degradation of space-exposed biosignatures such as pigments, secondary metabolites, and cell surfaces in contact with a terrestrial and Mars analog mineral environment. In parallel, analysis on the viability of the investigated organisms has provided relevant data for evaluation of the habitability of Mars, for the limits of life, and for the likelihood of an interplanetary transfer of life (theory of lithopanspermia)...
February 2019: Astrobiology
Theresa Backhaus, Joachim Meeßen, René Demets, Jean-Pierre de Vera, Sieglinde Ott
The lichen Buellia frigida was exposed to space and simulated Mars analog conditions in the Biology and Mars Experiment (BIOMEX) project operated outside the International Space Station (ISS) for 1.5 years. To determine the effects of the Low Earth Orbit (LEO) conditions on the lichen symbionts, a LIVE/DEAD staining analysis test was performed. After return from the ISS, the lichen symbionts demonstrated mortality rates of up to 100% for the algal symbiont and up to 97.8% for the fungal symbiont. In contrast, the lichen symbiont controls exhibited mortality rates of 10...
February 2019: Astrobiology
Thomas M McCollom, Christopher Donaldson
Formation of microtubules in volcanic glass from subsurface environments has been widely attributed to in situ activity of micro-organisms, but evidence directly linking those structures to biological processes remains lacking. Investigations into the alternative possibility of abiotic tubule formation have been limited. A laboratory experiment was conducted to examine whether moderate-temperature hydrothermal alteration of basaltic glass by seawater would produce structures similar to those ascribed to biological processes...
January 2019: Astrobiology
Janusz J Petkowski, William Bains, Sara Seager
A fundamental goal of biology is to understand the rules behind life's use of chemical space. Established work focuses on why life uses the chemistry that it does. Given the enormous scope of possible chemical space, we postulate that it is equally important to ask why life largely avoids certain areas of chemical space. The nitrogen-sulfur bond is a prime example, as it rarely appears in natural molecules, despite the very rich N-S bond chemistry applied in various branches of industry (e.g., industrial materials, agrochemicals, pharmaceuticals)...
November 15, 2018: Astrobiology
Constantinos M Paleos
Liquid crystals have certain physical properties that promote chemical reactions which cannot occur in bulk phase media. These properties are displayed, among other molecules, by amphiphilic compounds which assemble into membrane structures then concentrate and organize biologically relevant monomers within their confined spaces. When mixtures of lipids and nucleotides are cycled multiple times between hydrated and anhydrous conditions, the monomers polymerize in the dry phase into oligonucleotides. Upon rehydration, mixtures of the polymers are encapsulated in lipid-bounded compartments called protocells...
November 15, 2018: Astrobiology
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