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Origins of Life and Evolution of the Biosphere

Alberto Vázquez-Salazar, George Tan, Amanda Stockton, Renato Fani, Arturo Becerra, Antonio Lazcano
The five-membered heterocyclic imidazole group, which is an essential component of purines, histidine and many cofactors, has been abiotically synthesized in different model experiments that attempt to simulate the prebiotic environment. The evolutionary significance of imidazoles is highlighted not only by its presence in nucleic acid components and in histidine, but also by experimental reports of its ability to restore the catalytic activity of ribozymes. However, as of today there are no reports of histidine in carbonaceous chondrites, and although the abiotic synthesis of His reported by Shen et al...
October 22, 2016: Origins of Life and Evolution of the Biosphere
Erdmann Weronika, Kaczmarek Łukasz
To survive exposure to space conditions, organisms should have certain characteristics including a high tolerance for freezing, radiation and desiccation. The organisms with the best chance for survival under such conditions are extremophiles, like some species of Bacteria and Archea, Rotifera, several species of Nematoda, some of the arthropods and Tardigrada (water bears). There is no denying that tardigrades are one of the toughest animals on our planet and are the most unique in the extremophiles group...
October 20, 2016: Origins of Life and Evolution of the Biosphere
Punam Dalai, Hannes Lukas Pleyer, Henry Strasdeit, Stefan Fox
On the Hadean-Early Archean Earth, the first islands must have provided hot and dry environments for abiotically formed organic molecules. The heat sources, mainly volcanism and meteorite impacts, were also available on Mars during the Noachian period. In recent work simulating this scenario, we have shown that neat glycine forms a black, sparingly water-soluble polymer ("thermomelanoid") when dry-heated at 200 °C under pure nitrogen. The present study explores whether relevant minerals and mineral mixtures can change this thermal behavior...
October 18, 2016: Origins of Life and Evolution of the Biosphere
Xianlong Zhang, Ge Tian, Jing Gao, Mei Han, Rui Su, Yanxiang Wang, Shouhua Feng
Submarine hydrothermal vents are generally considered as the likely habitats for the origin and evolution of early life on Earth. In recent years, a novel hydrothermal system in Archean subseafloor has been proposed. In this model, highly alkaline and high temperature hydrothermal fluids were generated in basalt-hosted hydrothermal vents, where H2 and CO2 could be abundantly provided. These extreme conditions could have played an irreplaceable role in the early evolution of life. Nevertheless, sufficient information has not yet been obtained for the abiotic synthesis of amino acids, which are indispensable components of life, at high temperature and alkaline condition...
September 23, 2016: Origins of Life and Evolution of the Biosphere
Rui Huang, Yoshihiro Furukawa, Tsubasa Otake, Takeshi Kakegawa
The abiotic oligomerization of amino acids may have created primordial, protein-like biological catalysts on the early Earth. Previous studies have proposed and evaluated the potential of diagenesis for the amino acid oligomerization, simulating the formation of peptides that include glycine, alanine, and valine, separately. However, whether such conditions can promote the formation of peptides composed of multiple amino acids remains unclear. Furthermore, the chemistry of pore water in sediments should affect the oligomerization and degradation of amino acids and oligomers, but these effects have not been studied extensively...
September 23, 2016: Origins of Life and Evolution of the Biosphere
R L Mickol, T A Kral
The low pressure at the surface of Mars (average: 6 mbar) is one potentially biocidal factor that any extant life on the planet would need to endure. Near subsurface life, while shielded from ultraviolet radiation, would also be exposed to this low pressure environment, as the atmospheric gas-phase pressure increases very gradually with depth. Few studies have focused on low pressure as inhibitory to the growth or survival of organisms. However, recent work has uncovered a potential constraint to bacterial growth below 25 mbar...
September 23, 2016: Origins of Life and Evolution of the Biosphere
Fabrizio Dirri, Ernesto Palomba, Andrea Longobardo, Emiliano Zampetti
Piezoelectric Crystal Microbalances (PCM's) are widely used to study the chemical processes involving volatile compounds in any environment, such as condensation process. Since PCM's are miniaturized sensor, they are very suitable for planetary in situ missions, where can be used to detect and to measure the mass amount of astrobiologically significant compounds, such as water and organics. This work focuses on the realization and testing of a new experimental setup, able to characterize volatiles which can be found in a planetary environment...
September 15, 2016: Origins of Life and Evolution of the Biosphere
Norio Kitadai, Hiroyuki Oonishi, Koichiro Umemoto, Tomohiro Usui, Keisuke Fukushi, Satoru Nakashima
It has long been suggested that mineral surfaces played an important role in peptide bond formation on the primitive Earth. However, it remains unclear which mineral species was key to the prebiotic processes. This is because great discrepancies exist among the reported catalytic efficiencies of minerals for amino acid polymerizations, owing to mutually different experimental conditions. This study examined polymerization of glycine (Gly) on nine oxide minerals (amorphous silica, quartz, α-alumina and γ-alumina, anatase, rutile, hematite, magnetite, and forsterite) using identical preparation, heating, and analytical procedures...
July 29, 2016: Origins of Life and Evolution of the Biosphere
Luc van Heereveld, Jonathan Merrison, Per Nørnberg, Kai Finster
The increasing number of missions to Mars also increases the risk of forward contamination. Consequently there is a need for effective protocols to ensure efficient protection of the Martian environment against terrestrial microbiota. Despite the fact of constructing sophisticated clean rooms for spacecraft assembly a 100 % avoidance of contamination appears to be impossible. Recent surveys of these facilities have identified a significant number of microbes belonging to a variety of taxonomic groups that survive the harsh conditions of clean rooms...
July 26, 2016: Origins of Life and Evolution of the Biosphere
A Kereszturi, L Noack
In this work various factors on the habitability were considered, focusing on conditions irrespective of the central star's radiation, to see the role of specific planetary body related effects. These so called planetary factors were evaluated to identify those trans-domain issues where important information is missing but good chance exit to be filled by new knowledge that might be gained in the next decade(s). Among these strategic knowledge gaps, specific issues are listed, like occurrence of radioactive nucleides in star forming regions, models to estimate the existence of subsurface liquid water from bulk parameters plus evolutionary context of the given system, estimation on the existence of redox gradient depending on the environment type etc...
July 9, 2016: Origins of Life and Evolution of the Biosphere
Alan W Schwartz
No abstract text is available yet for this article.
July 6, 2016: Origins of Life and Evolution of the Biosphere
V Dehant, D Asael, R M Baland, B K Baludikay, J Beghin, J Belza, M Beuthe, D Breuer, S Chernonozhkin, Ph Claeys, Y Cornet, L Cornet, A Coyette, V Debaille, C Delvigne, M H Deproost, N De WInter, C Duchemin, F El Atrassi, C François, J De Keyser, C Gillmann, E Gloesener, S Goderis, Y Hidaka, D Höning, M Huber, G Hublet, E J Javaux, Ö Karatekin, J Kodolanyi, L Lobo Revilla, L Maes, R Maggiolo, N Mattielli, M Maurice, S McKibbin, A Morschhauser, W Neumann, L Noack, L B S Pham, L Pittarello, A C Plesa, A Rivoldini, S Robert, P Rosenblatt, T Spohn, J -Y Storme, N Tosi, A Trinh, M Valdes, A C Vandaele, F Vanhaecke, T Van Hoolst, N Van Roosbroek, V Wilquet, M Yseboodt
The Interuniversity Attraction Pole (IAP) 'PLANET TOPERS' (Planets: Tracing the Transfer, Origin, Preservation, and Evolution of their Reservoirs) addresses the fundamental understanding of the thermal and compositional evolution of the different reservoirs of planetary bodies (core, mantle, crust, atmosphere, hydrosphere, cryosphere, and space) considering interactions and feedback mechanisms. Here we present the first results after 2 years of project work.
June 23, 2016: Origins of Life and Evolution of the Biosphere
Vardan Adibekyan, Pedro Figueira, Nuno C Santos
We used a sample of super-Earth-like planets detected by the Doppler spectroscopy and transit techniques to explore the dependence of orbital parameters of the planets on the metallicity of their host stars. We confirm the previous results (although still based on small samples of planets) that super-Earths orbiting around metal-rich stars are not observed to be as distant from their host stars as we observe their metal-poor counterparts to be. The orbits of these super-Earths with metal-rich hosts usually do not reach into the Habitable Zone (HZ), keeping them very hot and inhabitable...
June 16, 2016: Origins of Life and Evolution of the Biosphere
Akimasa Fujihara, Hiroki Matsuyama, Michiko Tajiri, Yoshinao Wada, Shigeo Hayakawa
Enantioselective dissociation in the gas phase is important for enantiomeric enrichment and chiral transmission processes in molecular clouds regarding the origin of homochirality in biomolecules. Enantioselective collision-activated dissociation (CAD) of tryptophan (Trp) and the chiral recognition ability of L-alanine peptides (L-Ala n ; n = 2-4) were examined using a linear ion trap mass spectrometer. CAD spectra of gas-phase heterochiral H(+)(D-Trp)(L-Ala n ) and homochiral H(+)(L-Trp)(L-Ala n ) noncovalent complexes were obtained as a function of the peptide size n...
June 7, 2016: Origins of Life and Evolution of the Biosphere
L M Barge, E Branscomb, J R Brucato, S S S Cardoso, J H E Cartwright, S O Danielache, D Galante, T P Kee, Y Miguel, S Mojzsis, K J Robinson, M J Russell, E Simoncini, P Sobron
No abstract text is available yet for this article.
June 6, 2016: Origins of Life and Evolution of the Biosphere
Norio Kitadai
Polymerization of amino acids is a fundamentally important step for the chemical evolution of life. Nevertheless, its response to changing environmental conditions has not yet been well understood because of the lack of reliable quantitative information. For thermodynamics, detailed prediction over diverse combinations of temperature and pH has been made only for a few amino acid-peptide systems. This study used recently reported thermodynamic dataset for the polymerization of the simplest amino acid "glycine (Gly)" to its short peptides (di-glycine and tri-glycine) to examine chemical and structural characteristics of amino acids and peptides that control the temperature and pH dependence of polymerization...
June 1, 2016: Origins of Life and Evolution of the Biosphere
Brij Bhushan, Arunima Nayak, Kamaluddin
Origin of life processes might have begun with the formation of important biomonomers, such as amino acids and nucleotides, from simple molecules present in the prebiotic environment and their subsequent condensation to biopolymers. While studying the prebiotic synthesis of naturally occurring purine and pyrimidine derivatives from formamide, the manganese oxides demonstrated not only good binding for formamide but demonstrated novel catalytic activity. A novel one pot manganese oxide catalyzed synthesis of pyrimidine nucleobases like thymine is reported along with the formation of other nucleobases like purine, 9-(hydroxyacetyl) purine, cytosine, 4(3 H)-pyrimidinone and adenine in acceptable amounts...
June 2016: Origins of Life and Evolution of the Biosphere
S M Rolfe, M R Patel, I Gilmour, K Olsson-Francis, T J Ringrose
Biomarker molecules, such as amino acids, are key to discovering whether life exists elsewhere in the Solar System. Raman spectroscopy, a technique capable of detecting biomarkers, will be on board future planetary missions including the ExoMars rover. Generally, the position of the strongest band in the spectra of amino acids is reported as the identifying band. However, for an unknown sample, it is desirable to define multiple characteristic bands for molecules to avoid any ambiguous identification. To date, there has been no definition of multiple characteristic bands for amino acids of interest to astrobiology...
June 2016: Origins of Life and Evolution of the Biosphere
Alberto Zeffiro, Simone Lazzaroni, Daniele Merli, Antonella Profumo, Armando Buttafava, Nick Serpone, Daniele Dondi
Despite its importance in the prebiotic and biochemical fields, a complete theoretical study of the formation of hexamethylenetetramine (HMT) starting from its precursors ammonia and formaldehyde has not received due considerations in the literature with regard to the thermodynamic feasibility of many of the mechanistically proposed intermediates in its formation. Most of the studies in this area have been mostly concerned with the initial steps of the reaction between formaldehyde and ammonia, while poor attention is dedicated to successive steps...
June 2016: Origins of Life and Evolution of the Biosphere
Zachary R Adam
Geologic settings capable of driving prebiotic oligomer synthesis reactions remain a relatively unexplored aspect of origins of life research. Natural nuclear reactors are an example of Precambrian energy sources that produced unique temperature fluctuations. Heat transfer models indicate that water-moderated, convectively-cooled natural fission reactors in porous host rocks create temperature oscillations that resemble those employed in polymerase chain reaction (PCR) devices to artificially amplify oligonucleotides...
June 2016: Origins of Life and Evolution of the Biosphere
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