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Origins of Life and Evolution of the Biosphere

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https://www.readbyqxmd.com/read/28361302/transfer-of-asymmetry-between-proteinogenic-amino-acids-under-harsh-conditions
#1
Arkadii V Tarasevych, Thomas Vives, Valeriy N Snytnikov, Jean-Claude Guillemin
The heating above 400 °C of serine, cysteine, selenocysteine and threonine leads to a complete decomposition of the amino acids and to the formation in low yields of alanine for the three formers and of 2-aminobutyric acid for the latter. At higher temperature, this amino acid is observed only when sublimable α-alkyl-α-amino acids are present, and with an enantiomeric excess dependent on several parameters. Enantiopure or enantioenriched Ser, Cys, Sel or Thr is not able to transmit its enantiomeric excess to the amino acid formed during its decomposition...
March 31, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28361301/anoxic-and-oxic-oxidation-of-rocks-containing-fe-ii-mg-silicates-and-fe-ii-monosulfides-as-source-of-fe-iii-minerals-and-hydrogen-geobiotropy
#2
Marie-Paule Bassez
In this article, anoxic and oxic hydrolyses of rocks containing Fe (II) Mg-silicates and Fe (II)-monosulfides are analyzed at 25 °C and 250-350 °C. A table of the products is drawn. It is shown that magnetite and hydrogen can be produced during low-temperature (25 °C) anoxic hydrolysis/oxidation of ferrous silicates and during high-temperature (250 °C) anoxic hydrolysis/oxidation of ferrous monosulfides. The high-T (350 °C) anoxic hydrolysis of ferrous silicates leads mainly to ferric oxides/hydroxides such as the hydroxide ferric trihydroxide, the oxide hydroxide goethite/lepidocrocite and the oxide hematite, and to Fe(III)-phyllosilicates...
March 31, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28210992/the-comparison-of-hydrochloric-acid-and-phosphoric%C3%A2-acid-treatments-in-the-preparation-of-montmorillonite-catalysts-for-rna-synthesis
#3
Michael Frank Aldersley, Prakash C Joshi, Yixing Huang
The treatment of clay minerals with a preliminary acid wash and titration to pH 7 has proven to generate catalysts for the most interesting of oligomerization reactions in which activated RNA-nucleotides generate oligomers up to 40-mers. Significantly, not all clay minerals become catalytic following this treatment and none are catalytic in the absence of such treatment. The washing procedure has been modified and explored further using phosphoric acid and the outcomes are compared to those obtained when clay samples are prepared following a hydrochloric acid wash...
February 16, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28160163/nucleotide-selectivity-in-abiotic-rna-polymerization-reactions
#4
Kristin M Coari, Rebecca C Martin, Kopal Jain, Linda B McGown
In order to establish an RNA world on early Earth, the nucleotides must form polymers through chemical rather than biochemical reactions. The polymerization products must be long enough to perform catalytic functions, including self-replication, and to preserve genetic information. These functions depend not only on the length of the polymers, but also on their sequences. To date, studies of abiotic RNA polymerization generally have focused on routes to polymerization of a single nucleotide and lengths of the homopolymer products...
February 3, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27271006/thermodynamics-disequilibrium-evolution-far-from-equilibrium-geological-and-chemical-considerations-for-origin-of-life-research
#5
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.
March 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27251366/dissolved-divalent-metal-and-ph-effects-on-amino-acid-polymerization-a-thermodynamic-evaluation
#6
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...
March 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27245350/epimerization-of-alanyl-alanine-induced-by-%C3%AE-rays-irradiation-in-aqueous-solutions
#7
Toratane Munegumi
Living organisms have homochiral L-amino acids in proteins and homochiral D-mononucleotides in nucleic acids. The chemical evolutionary process to protein homochirality has been discussed for many years. Although many scenarios have been proposed for homochirality in the monomeric compounds, homochirality in amino acids and mononucleotides does not always guarantee homochirality in polypeptides and polynucleotides. Integrated scenarios containing the pathways from monomer to polymer should be proposed because in the pathways oligomers and polymers as well as monomers racemize (or epimerize), degrade, and condense...
March 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27207103/the-porphobilinogen-conundrum-in-prebiotic-routes-to-tetrapyrrole-macrocycles
#8
Masahiko Taniguchi, Marcin Ptaszek, Vanampally Chandrashaker, Jonathan S Lindsey
Attempts to develop a credible prebiotic route to tetrapyrroles have relied on enzyme-free recapitulation of the extant biosynthesis, but this process has foundered from the inability to form the pyrrole porphobilinogen (PBG) in good yield by self-condensation of the precursor δ-aminolevulinic acid (ALA). PBG undergoes robust oligomerization in aqueous solution to give uroporphyrinogen (4 isomers) in good yield. ALA, PBG, and uroporphyrinogen III are universal precursors to all known tetrapyrrole macrocycles...
March 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27072833/formation-of-diastereoisomeric-piperazine-2-5-dione-from-dl-alanine-in-the-presence-of-olivine-and-water
#9
Shigeshi Fuchida, Hiroshi Naraoka, Harue Masuda
DL-Alanine (Ala) was heated with/without powdered olivine and water at 120 °C for 8 days to investigate the formation of the diastereoisomers of piperazine-2,5-dione (diketopiperazine, DKP). When only DL-Ala was heated with a small amount of water, 3.0 % of DL-Ala changed to cis- and trans-DKP after 8 days. DKPs were not detected after heating when no water was added. The presence of a small amount of water is important factor controlling peptide production rates under thermal conditions. When DL-Ala was heated with olivine powder for 8 days, the yields of cis- and trans-DKP were 6...
March 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27068152/james-p-ferris-1932-2016
#10
A W Schwartz
No abstract text is available yet for this article.
March 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27029792/spontaneous-oligomerization-of-nucleotide-alternatives-in-aqueous-solutions
#11
Karen E Smith, Christopher H House, Jason P Dworkin, Michael P Callahan
On early Earth, a primitive polymer that could spontaneously form from likely available precursors may have preceded both RNA and DNA as the first genetic material. Here, we report that heated aqueous solutions containing 5-hydroxymethyluracil (HMU) result in oligomers of uracil, heated solutions containing 5-hydroxymethylcytosine (HMC) result in oligomers of cytosine, and heated solutions containing both HMU and HMC result in mixed oligomers of uracil and cytosine. Oligomerization of hydroxymethylated pyrimidines, which may have been abundant on the primitive Earth, might have been important in the development of simple informational polymers...
March 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/26968859/research-program-for-a-search-of-the-origin-of-darwinian-evolution-research-program-for-a-vesicle-based-model-of-the-origin-of-darwinian-evolution-on-prebiotic-early-earth
#12
Marc Tessera
The search for origin of 'life' is made even more complicated by differing definitions of the subject matter, although a general consensus is that an appropriate definition should center on Darwinian evolution (Cleland and Chyba 2002). Within a physical approach which has been defined as a level-4 evolution (Tessera and Hoelzer 2013), one mechanism could be described showing that only three conditions are required to allow natural selection to apply to populations of different system lineages. This approach leads to a vesicle- based model with the necessary properties...
March 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28078499/carbonaceous-chondrite-meteorites-the-chronicle-of-a-potential-evolutionary-path-between-stars-and-life
#13
Sandra Pizzarello, Everett Shock
The biogenic elements, H, C, N, O, P and S, have a long cosmic history, whose evolution can still be observed in diverse locales of the known universe, from interstellar clouds of gas and dust, to pre-stellar cores, nebulas, protoplanetary discs, planets and planetesimals. The best analytical window into this cosmochemical evolution as it neared Earth has been provided so far by the small bodies of the Solar System, some of which were not significantly altered by the high gravitational pressures and temperatures that accompanied the formation of larger planets and may carry a pristine record of early nebular chemistry...
January 11, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28025749/farewell-to-a-friend
#14
André Brack
No abstract text is available yet for this article.
December 26, 2016: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27933421/erratum-to-an-experimental-framework-for-generating-evolvable-chemical-systems-in-the-laboratory
#15
David A Baum, Kalin Vetsigian
No abstract text is available yet for this article.
December 8, 2016: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27896547/chemical-analysis-of-a-miller-type-complex-prebiotic-broth-part-ii-gas-oil-water-and-the-oil-water-interface
#16
Sabrina Scherer, Eva Wollrab, Luca Codutti, Teresa Carlomagno, Stefan Gomes da Costa, Andreas Volkmer, Amela Bronja, Oliver J Schmitz, Albrecht Ott
We have analyzed the chemical variety obtained by Miller-Urey-type experiments using nuclear magnetic resonance (NMR) spectroscopy and coherent anti-Stokes Raman scattering (CARS) spectroscopy, gas chromatography followed by mass spectrometry (GC/MS) and two-dimensional gas chromatography followed by mass spectrometry (GCxGC/MS). In the course of a running Miller-Urey-type experiment, a hydrophobic organic layer emerged besides the hydrophilic aqueous phase and the gaseous phase that were initially present...
November 28, 2016: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27864699/an-experimental-framework-for-generating-evolvable-chemical-systems-in-the-laboratory
#17
David A Baum, Kalin Vetsigian
Most experimental work on the origin of life has focused on either characterizing the chemical synthesis of particular biochemicals and their precursors or on designing simple chemical systems that manifest life-like properties such as self-propagation or adaptive evolution. Here we propose a new class of experiments, analogous to artificial ecosystem selection, where we select for spontaneously forming self-propagating chemical assemblages in the lab and then seek evidence of a response to that selection as a key indicator that life-like chemical systems have arisen...
November 18, 2016: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27807660/encapsulation-of-nucleic-acids-into-giant-unilamellar-vesicles-by-freeze-thaw-a-way-protocells-may-form
#18
Hai Qiao, Na Hu, Jin Bai, Lili Ren, Qing Liu, Liaoqiong Fang, Zhibiao Wang
Protocells are believed to consist of a lipid membrane and encapsulated nucleic acid. As the lipid membrane is impermeable to macromolecules like nucleic acids, the processes by which nucleic acids become encapsulated inside lipid membrane compartments are still unknown. In this paper, a freeze-thaw method was modified and applied to giant unilamellar vesicles (GUVs) and deoxyribonucleic acid (DNA) in mixed solution resulting in the efficient encapsulation of 6.4 kb plasmid DNA and similar length linear DNA into GUVs...
November 2, 2016: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27394670/review-on-the-role-of-planetary-factors-on-habitability
#19
REVIEW
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...
November 2016: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27337974/planet-topers-planets-tracing-the-transfer-origin-preservation-and-evolution-of-their-reservoirs
#20
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.
November 2016: Origins of Life and Evolution of the Biosphere
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