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Origins of Life and Evolution of the Biosphere

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https://www.readbyqxmd.com/read/28593333/survival-and-adaptation-of-the-thermophilic-species-geobacillus-thermantarcticus-in-simulated-spatial-conditions
#1
Paola Di Donato, Ida Romano, Vincenza Mastascusa, Annarita Poli, Pierangelo Orlando, Mariagabriella Pugliese, Barbara Nicolaus
Astrobiology studies the origin and evolution of life on Earth and in the universe. According to the panspermia theory, life on Earth could have emerged from bacterial species transported by meteorites, that were able to adapt and proliferate on our planet. Therefore, the study of extremophiles, i.e. bacterial species able to live in extreme terrestrial environments, can be relevant to Astrobiology studies. In this work we described the ability of the thermophilic species Geobacillus thermantarcticus to survive after exposition to simulated spatial conditions including temperature's variation, desiccation, X-rays and UVC irradiation...
June 8, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28484901/racemization-of-valine-by-impact-induced-heating
#2
Yoshihiro Furukawa, Atsushi Takase, Toshimori Sekine, Takeshi Kakegawa, Takamichi Kobayashi
Homochirality plays an important role in all living organisms but its origin remains unclear. It also remains unclear whether such chiral molecules survived terrestrial heavy impact events. Impacts of extraterrestrial objects on early oceans were frequent and could have affected the chirality of oceanic amino acids when such amino acids accumulated during impacts. This study investigated the effects of shock-induced heating on enantiomeric change of valine with minerals such as olivine ([Mg0.9, Fe0.1]2SiO4), hematite (Fe2O3), and calcite (CaCO3)...
May 9, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28474281/on-the-ability-of-formaldehyde-to-act-as-a-tethering-catalyst-in-water
#3
Mohammad P Jamshidi, Melissa J MacDonald, André M Beauchemin
The low concentration issue is a fundamental challenge when it comes to prebiotic chemistry, as macromolecular systems need to be assembled via intermolecular reactions, and this is inherently difficult in dilute solutions. This is especially true when the reactions are challenging, and reactions that proceeded more rapidly could have dictated chemical evolution. Herein we establish that formaldehyde is capable of catalyzing, via temporary intramolecularity, a challenging reaction in water at low concentrations, thus providing an alternative to other approaches that can either lead to higher concentrations or higher effective molarities...
May 4, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28470374/cataclysm-no-more-new-views-on-the-timing-and-delivery-of-lunar-impactors
#4
Nicolle E B Zellner
If properly interpreted, the impact record of the Moon, Earth's nearest neighbour, can be used to gain insights into how the Earth has been influenced by impacting events since its formation ~4.5 billion years (Ga) ago. However, the nature and timing of the lunar impactors - and indeed the lunar impact record itself - are not well understood. Of particular interest are the ages of lunar impact basins and what they tell us about the proposed "lunar cataclysm" and/or the late heavy bombardment (LHB), and how this impact episode may have affected early life on Earth or other planets...
May 3, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28432500/walking-over-4-gya-chemical-evolution-from-photochemistry-to-mineral-and-organic-chemistries-leading-to-an-rna-world
#5
REVIEW
Kunio Kawamura, Marie-Christine Maurel
Here we overview the chemical evolution of RNA molecules from inorganic material through mineral-mediated RNA formation compatible with the plausible early Earth environments. Pathways from the gas-phase reaction to the formation of nucleotides, activation and oligomerization of nucleotides, seem to be compatible with specific environments. However, how these steps interacted is not clear since the chemical conditions are frequently different and can be incompatible between them; thus the products would have migrated from one place to another, suitable for further chemical evolution...
April 21, 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/28361302/transfer-of-asymmetry-between-proteinogenic-amino-acids-under-harsh-conditions
#6
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
#7
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/27663449/effects-of-glycine-water-ammonia-and-ammonium-bicarbonate-on-the-oligomerization-of-methionine
#8
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...
June 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27473494/glycine-polymerization-on-oxide-minerals
#9
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...
June 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27461254/assessment-of-the-forward-contamination-risk-of-mars-by-clean-room-isolates-from-space-craft-assembly-facilities-through-aeolian-transport-a-model-study
#10
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...
June 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27383153/editorial-reworking-drake
#11
EDITORIAL
Alan W Schwartz
No abstract text is available yet for this article.
June 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27271107/enantioselective-collision-activated-dissociation-of-gas-phase-tryptophan-induced-by-chiral-recognition-of-protonated-l-alanine-peptides
#12
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 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27033201/biomex-experiment-ultrastructural-alterations-molecular-damage-and-survival-of-the-fungus-cryomyces-antarcticus-after-the-experiment-verification-tests
#13
Claudia Pacelli, Laura Selbmann, Laura Zucconi, Jean-Pierre De Vera, Elke Rabbow, Gerda Horneck, Rosa de la Torre, Silvano Onofri
The search for traces of extinct or extant life in extraterrestrial environments is one of the main goals for astrobiologists; due to their ability to withstand stress producing conditions, extremophiles are perfect candidates for astrobiological studies. The BIOMEX project aims to test the ability of biomolecules and cell components to preserve their stability under space and Mars-like conditions, while at the same time investigating the survival capability of microorganisms. The experiment has been launched into space and is being exposed on the EXPOSE-R2 payload, outside of the International Space Station (ISS) over a time-span of 1...
June 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/27025932/the-first-space-related-study-of-a-kombucha-multimicrobial-cellulose-forming-community-preparatory-laboratory-experiments
#14
O Podolich, I Zaets, O Kukharenko, I Orlovska, O Reva, L Khirunenko, M Sosnin, A Haidak, S Shpylova, I Rohutskyy, A Kharina, М Skoryk, M Kremenskoy, D Klymchuk, R Demets, J-P de Vera, N Kozyrovska
Biofilm-forming microbial communities are known as the most robust assemblages that can survive in harsh environments. Biofilm-associated microorganisms display greatly increased resistance to physical and chemical adverse conditions, and they are expected to be the first form of life on Earth or anywhere else. Biological molecules synthesized by biofilm -protected microbiomes may serve as markers of the nucleoprotein life. We offer a new experimental model, a kombucha multimicrobial culture (KMC), to assess a structural integrity of a widespread microbial polymer - cellulose - as a biosignature of bacteria-producers for the multipurpose international project "BIOlogical and Mars Experiment (BIOMEX)", which aims to study the vitality of pro- and eukaryotic organisms and the stability of organic biomolecules in contact with minerals to analyze the detectability of life markers in the context of a planetary background...
June 2017: Origins of Life and Evolution of the Biosphere
https://www.readbyqxmd.com/read/26907768/formation-of-hexamethylenetetramine-comment
#15
EDITORIAL
Vassilissa Vinogradoff, Albert Rimola, Fabrice Duvernay, Gregoire Danger, Patrice Theulé, Thierry Chiavassa
No abstract text is available yet for this article.
June 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
#16
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
#17
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
#18
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
#19
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
#20
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
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