Kashyap, Srishti Sklute, Elizabeth C Wang, Peng Tague, Thomas J Jr Dyar, M Darby Holden, James F
Published in
Astrobiology
Mineral transformations by two hyperthermophilic Fe(III)-reducing crenarchaea, Pyrodictium delaneyi and Pyrobaculum islandicum, were examined using synthetic nanophase ferrihydrite, lepidocrocite, and akaganeite separately as terminal electron acceptors and compared with abiotic mineral transformations under similar conditions. Spectral analyses us...
Nikitczuk, Matthew P Bebout, Gray E Geiger, Charles A Ota, Tsutomu Kunihiro, Takuya Mustard, John F Halldórsson, Sæmundur A Nakamura, Eizo
Published in
Astrobiology
We measured the N concentrations and isotopic compositions of 44 samples of terrestrial potassic and micro- and meso-porous minerals and a small number of whole-rocks to determine the extent to which N is incorporated and stored during weathering and low-temperature hydrothermal alteration in Mars surface/near-surface environments. The selection of...
Choe, Joong Chul
Published in
Astrobiology
The potential energy surface for the formation of protonated uracil (UH+) from urea and HC3O+ was explored by performing quantum chemical complete basis set-QB3 calculations. A barrierless pathway was found for the formation of UH+, which was estimated to occur in the interstellar medium (ISM) much faster than the timescale of chemical revolution o...
González-Ramírez, Luis A Moreno, Abel Ng, Joseph D García-Ruiz, Juan M
Published in
Astrobiology
The mineral reaction pathways that yield organic compounds of increasing complexity would have required a means of protective screening against strong ultraviolet radiation for macromolecular assembly on early Earth. In this study, a bacterial chromosomal plasmid DNA was used as a model biomolecule that represents a complex polymeric nucleic acid c...
Billi, Daniela Blanco, Yolanda Ianneo, Andrea Moreno-Paz, Mercedes Aguirre, Jacobo Baqué, Mickael Moeller, Ralf de Vera, Jean-Pierre Parro, Victor
Published in
Astrobiology
The effect of a Mars-like UV flux and γ-radiation on the detectability of biomarkers in dried cells of Chroococcidiopsis sp. CCMEE 029 was investigated using a fluorescence sandwich microarray immunoassay. The production of anti-Chroococcidiopsis antibodies allowed the immunoidentification of a reduced, though still detectable, signal in dried cell...
Duhamel, Solange Hamilton, Christopher Ward Pálsson, Snæbjörn Björnsdóttir, Snædís Huld
Published in
Astrobiology
Fossil hydrothermal systems on Mars are important exploration targets because they may have once been habitable and could still preserve evidence of microbial life. We investigated microbial communities within an active lava-induced hydrothermal system associated with the 2014-2015 eruption of Holuhraun in Iceland as a Mars analogue. In 2016, the m...
Osterhout, Jeffrey T Schopf, J William Kudryavtsev, Anatoliy B Czaja, Andrew D Williford, Kenneth H
Published in
Astrobiology
The current strategy for detecting evidence of ancient life on Mars-a primary goal of NASA's ongoing Mars 2020 mission-is based largely on knowledge of Precambrian life and of its preservation in Earth's early rock record. The fossil record of primitive microorganisms consists mainly of stromatolites and other microbially influenced sedimentary str...
Bak, Ebbe Norskov Bregnhøj, Mikkel Nørnberg, Per Jensen, Svend J Knak Thøgersen, Jan Finster, Kai
Published in
Astrobiology
Hickman-Lewis, Keyron Moore, Kelsey R Hollis, Joseph J Razzell Tuite, Michael L Beegle, Luther W Bhartia, Rohit Grotzinger, John P Brown, Adrian J Shkolyar, Svetlana Cavalazzi, Barbara
...
Published in
Astrobiology
The NASA Mars 2020 Perseverance rover is currently exploring Jezero crater, a Noachian-Hesperian locality that once hosted a delta-lake system with high habitability and biosignature preservation potential. Perseverance conducts detailed appraisals of rock targets using a synergistic payload capable of geological characterization from kilometer to ...
Shoji, Mitsuo Watanabe, Natsuki Hori, Yuta Furuya, Kenji Umemura, Masayuki Boero, Mauro Shigeta, Yasuteru
Published in
Astrobiology
Enantiomeric excesses of l-amino acids have been detected in meteorites; however, their molecular mechanism and prebiotic syntheses are still a matter of debate. To elucidate the origin of homochirality, alanine and the chiral precursors formed in prebiotic processes were investigated with regard to their stabilities among their isomers by employin...