scholarly journals Exploring the Emergence of RNA Nucleosides and Nucleotides on the Early Earth

Life ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 57 ◽  
Author(s):  
Annabelle Biscans
Keyword(s):  
Amino Acids ◽  
Chemical Reactions ◽  
Early Earth ◽  
Evolution Of Life ◽  
Cellular Components

Understanding how life began is one of the most fascinating problems to solve. By approaching this enigma from a chemistry perspective, the goal is to define what series of chemical reactions could lead to the synthesis of nucleotides, amino acids, lipids, and other cellular components from simple feedstocks under prebiotically plausible conditions. It is well established that evolution of life involved RNA which plays central roles in both inheritance and catalysis. In this review, we present historically important and recently published articles aimed at understanding the emergence of RNA nucleosides and nucleotides on the early Earth.

scholarly journals Prebiotic materials from on and off the early Earth

2006 ◽  
Vol 361 (1474) ◽  
pp. 1689-1702 ◽  
Author(s):  
Max Bernstein
Keyword(s):  
Amino Acids ◽  
Solar System ◽  
Oxidation State ◽  
Hydrothermal Vents ◽  
Organic Molecules ◽  
Early Earth ◽  
The Earth ◽  
Evolution Of Life ◽  
Carbon Compounds ◽  
Compare And Contrast

One of the greatest puzzles of all time is how did life arise? It has been universally presumed that life arose in a soup rich in carbon compounds, but from where did these organic molecules come? In this article, I will review proposed terrestrial sources of prebiotic organic molecules, such as Miller–Urey synthesis (including how they would depend on the oxidation state of the atmosphere) and hydrothermal vents and also input from space. While the former is perhaps better known and more commonly taught in school, we now know that comet and asteroid dust deliver tons of organics to the Earth every day, therefore this flux of reduced carbon from space probably also played a role in making the Earth habitable. We will compare and contrast the types and abundances of organics from on and off the Earth given standard assumptions. Perhaps each process provided specific compounds (amino acids, sugars, amphiphiles) that were directly related to the origin or early evolution of life. In any case, whether planetary, nebular or interstellar, we will consider how one might attempt to distinguish between abiotic organic molecules from actual signs of life as part of a robotic search for life in the Solar System.

Effects of Amino Acids on Phosphate Adsorption Onto Iron (Oxy)hydroxide Minerals under Early Earth Conditions

2021 ◽  
Author(s):  
Erika Flores ◽  
Eduardo Martinez ◽  
Laura E. Rodriguez ◽  
Jessica M. Weber ◽  
Arezoo Khodayari ◽  
...  
Keyword(s):  
Amino Acids ◽  
Phosphate Adsorption ◽  
Early Earth

scholarly journals Chemical Reactions of Amino Acids with Aldehydes. Part VI

1961 ◽  
Vol 35 (11) ◽  
pp. 1027-1029
Author(s):  
Sakae EMOTO ◽  
Makoto ANDO
Keyword(s):  
Amino Acids ◽  
Chemical Reactions

Chemically Selective Reactions in Confined Spaces in Hybrid Aerogels

2005 ◽  
Vol 899 ◽  
Author(s):  
Xipeng Liu ◽  
Chunhua Yao ◽  
William M Risen
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Metal Ions ◽  
Chemical Reactions ◽  
Reaction Products ◽  
Spatial Confinement ◽  
Confined Spaces ◽  
Hybrid Silica ◽  
Hybrid Aerogels ◽  
Chemically Selective

AbstractBy employing novel hybrid silica/functional polymer aerogels, control of the course of chemical reactions between reactants confined inside of the aerogels with reactants whose access to the confinement domain is controlled by diffusion has been explored. Thus, monolithic silica/biopolymer hybrid aerogels have been synthesized with coordinated metal ions that can react with amino acids, such as L-cysteine, that are provided externally in a surrounding solution. Metal ions, such as Au(III), that can react in solution with the amino acid to produce one set of products under a given set of stoichiometric or concentration conditions, and a different set of products under a second set of conditions, were selected for incorporation into the aerogel. It was discovered that the course of the reaction can be changed by spatial confinement of the reaction domain in the aerogel. For example, in the case of Au(III) and L-cysteine, the Au(III) ions are confined in nanoscale domains, and when they are reacted with the amino acid, the nature of the reaction products is controlled by diffusion of the L-cysteine into the domains. Exploration of these and related phenomena will be presented.

scholarly journals Chemical Reactions of Amino Acids with Aldehydes. Part IV

1961 ◽  
Vol 35 (10) ◽  
pp. 957-962
Author(s):  
Sakae EMOTO ◽  
Makoto ANDO
Keyword(s):  
Amino Acids ◽  
Chemical Reactions

scholarly journals Mercury isotope signatures record photic zone euxinia in the Mesoproterozoic ocean

2018 ◽  
Vol 115 (42) ◽  
pp. 10594-10599 ◽  
Author(s):  
Wang Zheng ◽  
Geoffrey J. Gilleaudeau ◽  
Linda C. Kah ◽  
Ariel D. Anbar
Keyword(s):  
Isotope Fractionation ◽  
Sedimentary Rocks ◽  
Early Earth ◽  
Photic Zone ◽  
Mass Extinctions ◽  
Mercury Isotope ◽  
Independent Evidence ◽  
Surface Ocean ◽  
Negative Shift ◽  
Evolution Of Life

Photic zone euxinia (PZE) is a condition where anoxic, H2S-rich waters occur in the photic zone (PZ). PZE has been invoked as an impediment to the evolution of complex life on early Earth and as a kill mechanism for Phanerozoic mass extinctions. Here, we investigate the potential application of mercury (Hg) stable isotopes in marine sedimentary rocks as a proxy for PZE by measuring Hg isotope compositions in late Mesoproterozoic (∼1.1 Ga) shales that have independent evidence of PZE during discrete intervals. Strikingly, a significantly negative shift of Hg mass-independent isotope fractionation (MIF) was observed during euxinic intervals, suggesting changes in Hg sources or transformations in oceans coincident with the development of PZE. We propose that the negative shift of Hg MIF was most likely caused by (i) photoreduction of Hg(II) complexed by reduced sulfur ligands in a sulfide-rich PZ, and (ii) enhanced sequestration of atmospheric Hg(0) to the sediments by thiols and sulfide that were enriched in the surface ocean as a result of PZE. This study thus demonstrates that Hg isotope compositions in ancient marine sedimentary rocks can be a promising proxy for PZE and therefore may provide valuable insights into changes in ocean chemistry and its impact on the evolution of life.

Autocatalytic chemical networks preceded proteins and RNA in evolution

2019 ◽  
Author(s):  
Joana C. Xavier ◽  
Wim Hordijk ◽  
Stuart Kauffman ◽  
Mike Steel ◽  
William F. Martin
Keyword(s):  
Amino Acids ◽  
Origin Of Life ◽  
Small Molecule ◽  
Metabolic Networks ◽  
Early Earth ◽  
Prebiotic Evolution ◽  
Biochemical Evolution ◽  
The Origin Of Life ◽  
Acids And Bases ◽  
Open Question

AbstractModern cells embody metabolic networks containing thousands of elements and form autocatalytic molecule sets that produce copies of themselves. How the first self-sustaining metabolic networks arose at life’ s origin is a major open question. Autocatalytic molecule sets smaller than metabolic networks were proposed as transitory intermediates at the origin of life, but evidence for their role in prebiotic evolution is lacking. Here we identify reflexively autocatalytic food-generated networks (RAFs)—self-sustaining networks that collectively catalyze all their reactions—embedded within microbial metabolism. RAFs in the metabolism of ancient anaerobic autotrophs that live from H2 and CO2 generate amino acids and bases, the monomeric components of protein and RNA, and acetyl-CoA, but amino acids and bases do not generate metabolic RAFs, indicating that small-molecule catalysis preceded polymers in biochemical evolution. RAFs uncover intermediate stages in the origin of metabolic networks, narrowing the gaps between early-Earth chemistry and life.

scholarly journals Provisioning the origin and early evolution of life

2019 ◽  
Vol 3 (5) ◽  
pp. 459-468 ◽  
Author(s):  
Long-Fei Wu ◽  
John D. Sutherland
Keyword(s):  
Energy Source ◽  
Amino Acids ◽  
Early Life ◽  
Reaction Network ◽  
Building Blocks ◽  
Early Evolution ◽  
Synthesis Conditions ◽  
Contentious Issue ◽  
First Case ◽  
Evolution Of Life

There is a lot of controversy in the origin and early evolution of life field, but most people agree that at the advent of genetically coded protein synthesis, cells must have had access to ribonucleotides, amino acids, lipids and some sort of energy source. However, the provenance of these materials is a contentious issue — did early life obtain its building blocks prefabricated from the environment, or did it synthesise them from feedstocks such as CO2 and N2? In the first case, synthesis conditions need not have been compatible with life and any kind of reaction network that furnished the building blocks — and not much else — could have provisioned the subsequent origin and early evolution of life. In the second case, synthesis must have been under life-compatible conditions, with the reaction network either along the same lines as extant biology or along different ones. On the basis of experimental evidence, we will argue in favour of prefabrication and against synthesis by life in its nascent state, especially synthesis that resembles extant biosynthesis, which we suggest would have been well-nigh impossible without biological catalysts.

scholarly journals The biology, function, and biomedical applications of exosomes

Science ◽  
2020 ◽  
Vol 367 (6478) ◽  
pp. eaau6977 ◽  
Author(s):  
Raghu Kalluri ◽  
Valerie S. LeBleu
Keyword(s):  
Amino Acids ◽  
Extracellular Vesicles ◽  
Intercellular Communication ◽  
Biomedical Applications ◽  
Molecular Mechanisms ◽  
Biological Fluids ◽  
Average Diameter ◽  
Cell Of Origin ◽  
Intracellular Vesicles ◽  
Cellular Components

The study of extracellular vesicles (EVs) has the potential to identify unknown cellular and molecular mechanisms in intercellular communication and in organ homeostasis and disease. Exosomes, with an average diameter of ~100 nanometers, are a subset of EVs. The biogenesis of exosomes involves their origin in endosomes, and subsequent interactions with other intracellular vesicles and organelles generate the final content of the exosomes. Their diverse constituents include nucleic acids, proteins, lipids, amino acids, and metabolites, which can reflect their cell of origin. In various diseases, exosomes offer a window into altered cellular or tissue states, and their detection in biological fluids potentially offers a multicomponent diagnostic readout. The efficient exchange of cellular components through exosomes can inform their applied use in designing exosome-based therapeutics.

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