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Origin of Life in Chemically Complex Messy Environments
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Origin of Life in Chemically Complex Messy Environments

A special issue of Life (ISSN 2075-1729). This special issue belongs to the section "Origin of Life".

Deadline for manuscript submissions: closed (31 December 2022) | Viewed by 35575

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editors

Dr. Ranajay Saha

E-Mail Website
Guest Editor
Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA
Interests: origin of life; prebiotic evolution; RNA world; minimal synthetic cells; molecular biology; protein and RNA biophysics; macromolecular crowding and confinement; UV damage; fluorescence spectroscopy
Special Issues, Collections and Topics in MDPI journals
Dr. Alberto Vázquez-Salazar

E-Mail Website
Guest Editor
Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA
Interests: origin of life; RNA world; early evolution of life
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Traditionally, the vast majority of prebiotic chemistry research has consisted of experiments focused on the behavior of a restricted spectrum of organic molecules, usually studying the components of life separately, where the results are limited by the simulated scenario, also described as "clean and isolated" experiments. However, research on the origin of life needs to think big and outside the box in order to enable continuous progress in the field. Considering the prebiotic Earth four billion years ago (a messy atmosphere, in other words), a chaotic mélange of diverse starting materials appears realistic. As prebiotic chemists and origin-of-life researchers, we must modify our current approach and consider more chemical and geological scenarios in which both physical processes and driving forces towards primitive life formation are examined. In this Special Issue, we welcome the submission of original research papers, comprehensive reviews, and perspectives that demonstrate or summarize advances related to the origin of life in various complex chemical and prebiotically feasible environments.

Dr. Ranajay Saha
Dr. Alberto Vázquez-Salazar 
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Life is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • origin of life
  • complex chemical systems
  • prebiotic chemistry
  • prebiotic metabolisms
  • chemical evolution
  • prebiotic catalysts

Published Papers (15 papers)

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Research

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16 pages, 1882 KiB  
Article
Prebiotic Chemistry of Phosphite: Mild Thermal Routes to Form Condensed-P Energy Currency Molecules Leading Up to the Formation of Organophosphorus Compounds
by Maheen Gull, Tian Feng, Harold A. Cruz, Ramanarayanan Krishnamurthy and Matthew A. Pasek
Life 2023, 13(4), 920; https://doi.org/10.3390/life13040920 - 31 Mar 2023
Cited by 3 | Viewed by 1962
Abstract
The in-fall of meteorites and interstellar dust particles during the Hadean–Archean heavy bombardment may have provided the early Earth with various reduced oxidation state phosphorus compounds and minerals, including phosphite (HPO32−)([Pi(III)]). The ion phosphite ([Pi(III)])has been postulated to be ubiquitous [...] Read more.
The in-fall of meteorites and interstellar dust particles during the Hadean–Archean heavy bombardment may have provided the early Earth with various reduced oxidation state phosphorus compounds and minerals, including phosphite (HPO32−)([Pi(III)]). The ion phosphite ([Pi(III)])has been postulated to be ubiquitous on the early Earth and consequently could have played a role in the emergence of organophosphorus compounds and other prebiotically relevant P species such as condensed P compounds, e.g., pyrophosphite ([PPi(III)]) and isohypophosphate ([PPi(III–V)]). In the present study, we show that phosphite ([Pi(III)]) oxidizes under mild heating conditions (e.g., wet–dry cycles and a prebiotic scenario mimicking a mildly hot-evaporating/drying pool on the early Earth at 78–83 °C) in the presence of urea and other additives, resulting in changes to orthophosphate ([Pi(V)]) alongside the formation of reactive condensed P compounds (e.g., pyrophosphite ([PPi(III)]) and isohypophosphate ([PPi(III–V)])) through a one-pot mechanism. Additionally, we also show that phosphite ([Pi(III)]) and the condensed P compounds readily react with organics (nucleosides and organic alcohol) to form organophosphorus compounds. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
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20 pages, 6811 KiB  
Article
A New Approach in Prebiotic Chemistry Studies: Proline Sorption Triggered by Mineral Surfaces Analysed Using XPS
by Eduardo J. Cueto-Díaz, Santos Gálvez-Martínez, María Colin-García and Eva Mateo-Martí
Life 2023, 13(4), 908; https://doi.org/10.3390/life13040908 - 30 Mar 2023
Viewed by 1949
Abstract
The role of minerals in the origin of life and prebiotic evolution remains unknown and controversial. Mineral surfaces have the potential to facilitate prebiotic polymerization due to their ability to adsorb and concentrate biomolecules that subsequently can catalyse reactions; however, the precise nature [...] Read more.
The role of minerals in the origin of life and prebiotic evolution remains unknown and controversial. Mineral surfaces have the potential to facilitate prebiotic polymerization due to their ability to adsorb and concentrate biomolecules that subsequently can catalyse reactions; however, the precise nature of the interaction between the mineral host and the guest biomolecule still needs to be understood. In this context, we spectroscopically characterized, using infrared, X-ray photoemission spectroscopy (XPS) and X-ray diffraction (XRD) techniques, the interaction between L-proline and montmorillonite, olivine, iron disulphide, and haematite (minerals of prebiotic interest), by evaluating their interaction from a liquid medium. This work provides insight into the chemical processes occurring between proline, the only cyclic amino acid, and this selection of minerals, each of them bearing a particular chemical and crystal structures. Proline was successfully adsorbed on montmorillonite, haematite, olivine, and iron disulphide in anionic and zwitterionic chemical forms, being the predominant form directly related to the mineral structure and composition. Silicates (montmorillonite) dominate adsorption, whereas iron oxides (haematite) show the lowest molecular affinity. This approach will help to understand structure-affinity relationship between the mineral surfaces and proline, one of the nine amino acids generated in the Miller-Urey experiment. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
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38 pages, 17701 KiB  
Article
“Sea Water” Supplemented with Calcium Phosphate and Magnesium Sulfate in a Long-Term Miller-Type Experiment Yields Sugars, Nucleic Acids Bases, Nucleosides, Lipids, Amino Acids, and Oligopeptides
by Robert Root-Bernstein, Andrew G. Baker, Tyler Rhinesmith, Miah Turke, Jack Huber and Adam W. Brown
Life 2023, 13(2), 265; https://doi.org/10.3390/life13020265 - 18 Jan 2023
Cited by 2 | Viewed by 1730
Abstract
The standard approach to exploring prebiotic chemistry is to use a small number of highly purified reactants and to attempt to optimize the conditions required to produce a particular end product. However, purified reactants do not exist in nature. We have previously proposed [...] Read more.
The standard approach to exploring prebiotic chemistry is to use a small number of highly purified reactants and to attempt to optimize the conditions required to produce a particular end product. However, purified reactants do not exist in nature. We have previously proposed that what drives prebiotic evolution are complex chemical ecologies. Therefore, we have begun to explore what happens if one substitutes “sea water”, with its complex mix of minerals and salts, for distilled water in the classic Miller experiment. We have also adapted the apparatus to permit it to be regassed at regular intervals so as to maintain a relatively constant supply of methane, hydrogen, and ammonia. The “sea water” used in the experiments was created from Mediterranean Sea salt with the addition of calcium phosphate and magnesium sulfate. Tests included several types of mass spectrometry, an ATP-monitoring device capable of measuring femtomoles of ATP, and a high-sensitivity cAMP enzyme-linked immunoadsorption assay. As expected, amino acids appeared within a few days of the start of the experiment and accumulated thereafter. Sugars, including glucose and ribose, followed as did long-chain fatty acids (up to C20). At three-to-five weeks after starting the experiment, ATP was repeatedly detected. Thus, we have shown that it is possible to produce a “one-pot synthesis” of most of the key chemical prerequisites for living systems within weeks by mimicking more closely the complexity of real-world chemical ecologies. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
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10 pages, 603 KiB  
Article
Role of Stress in the Origin of Life
by Vladimir Kompanichenko and Oleg Kotsyurbenko
Life 2022, 12(11), 1930; https://doi.org/10.3390/life12111930 - 18 Nov 2022
Cited by 2 | Viewed by 1722
Abstract
The article shows the compatibility of the concept of thermodynamic inversion (TI) of the origin of life with the theory of stress in (micro)biology. According to the proposed TI concept, the first microorganisms on Earth were formed through an effective (intensified and purposeful) [...] Read more.
The article shows the compatibility of the concept of thermodynamic inversion (TI) of the origin of life with the theory of stress in (micro)biology. According to the proposed TI concept, the first microorganisms on Earth were formed through an effective (intensified and purposeful) response of organic microsystems to incessant oscillations of physicochemical parameters (i.e., to periodic stress) in a hydrothermal environment. This approach allows us to explain the ability of contemporary microorganisms to respond to stress at the individual and population levels. The ability of microorganisms to effectively react to environmental stress factors is corroborated by a number of molecular and other mechanisms that are described in the article. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
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19 pages, 4043 KiB  
Article
Stability of DL-Glyceraldehyde under Simulated Hydrothermal Conditions: Synthesis of Sugar-like Compounds in an Iron(III)-Oxide-Hydroxide-Rich Environment under Acidic Conditions
by Claudio Alejandro Fuentes-Carreón, Jorge Armando Cruz-Castañeda, Eva Mateo-Martí and Alicia Negrón-Mendoza
Life 2022, 12(11), 1818; https://doi.org/10.3390/life12111818 - 8 Nov 2022
Cited by 1 | Viewed by 2351
Abstract
Researchers have suggested that the condensation of low-molecular-weight aldehydes under basic conditions (e.g., pH > 11) is the prebiotic reaction responsible for the abiotic formation of carbohydrates. It has also been suggested that surface hydrothermal systems were ubiquitous during the early Archean period. [...] Read more.
Researchers have suggested that the condensation of low-molecular-weight aldehydes under basic conditions (e.g., pH > 11) is the prebiotic reaction responsible for the abiotic formation of carbohydrates. It has also been suggested that surface hydrothermal systems were ubiquitous during the early Archean period. Therefore, the catalysis of prebiotic carbohydrate synthesis by metallic oxide minerals under acidic conditions in these environments seems considerably more probable than the more widely hypothesized reaction routes. This study investigates the stability of DL-glyceraldehyde and its reaction products under the simulated conditions of an Archean surface hydrothermal system. The Hveradalur geothermal area in Iceland was selected as an analog of such a system. HPLC-ESIMS, UV–Vis spectroscopy, Raman spectroscopy and XPS spectroscopy were used to analyze the reaction products. In hot (323 K) and acidic (pH 2) solutions under the presence of suspended iron(III) oxide hydroxide powder, DL-glyceraldehyde readily decomposes into low-molecular-weight compounds and transforms into sugar-like molecules via condensation reactions. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
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22 pages, 3490 KiB  
Article
Komatiites as Complex Adsorption Surfaces for Amino Acids in Prebiotic Environments, a Prebiotic Chemistry Essay
by Abigail E. Cruz-Hernández, María Colín-García, Fernando Ortega-Gutiérrez and Eva Mateo-Martí
Life 2022, 12(11), 1788; https://doi.org/10.3390/life12111788 - 4 Nov 2022
Cited by 2 | Viewed by 1408
Abstract
Komatiites represent the oldest known terrestrial rocks, and their composition has been cataloged as the closest to that of the first terrestrial crust after the cooling of the magma ocean. These rocks could have been present in multiple environments on the early Earth [...] Read more.
Komatiites represent the oldest known terrestrial rocks, and their composition has been cataloged as the closest to that of the first terrestrial crust after the cooling of the magma ocean. These rocks could have been present in multiple environments on the early Earth and served as concentrators of organic molecules. In this study, the adsorption of five amino acids (glycine, lysine, histidine, arginine, and aspartic acid) on a natural komatiite, a simulated komatiite, and the minerals olivine, pyroxene, and plagioclase were analyzed under three different pH values: acid pH (5.5), natural pH of the aqueous solution of each amino acid and alkaline pH (11). Adsorption experiments were performed in solid–liquid suspensions and organic molecules were analyzed by spectrophotometry. The main objective of this essay was to determine if the complex surfaces could have participated as concentrators of amino acids in scenarios of the primitive Earth and if the adsorption responds to the change of charge of the molecules. The results showed that komatiite is capable of adsorbing amino acids in different amounts depending on the experimental conditions. In total, 75 systems were analyzed that show different adsorptions, which implies that different interactions are involved, particularly in relation to the type of amino acid, the type of solid material and the conditions of the medium. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
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9 pages, 1357 KiB  
Communication
Results of an Eight-Year Extraction of Phosphorus Minerals within the Seymchan Meteorite
by Maheen Gull, Tian Feng and Matthew A. Pasek
Life 2022, 12(10), 1591; https://doi.org/10.3390/life12101591 - 12 Oct 2022
Cited by 3 | Viewed by 2241
Abstract
In-fall of extraterrestrial material including meteorites and interstellar dust particles during the late heavy bombardment are known to have brought substantial amounts of reduced oxidation-state phosphorus to the early Earth in the form of siderophilic minerals, e.g., schreibersite ((FeNi)3P). In this [...] Read more.
In-fall of extraterrestrial material including meteorites and interstellar dust particles during the late heavy bombardment are known to have brought substantial amounts of reduced oxidation-state phosphorus to the early Earth in the form of siderophilic minerals, e.g., schreibersite ((FeNi)3P). In this report, we present results on the reaction of meteoritic phosphide minerals in the Seymchan meteorite in ultrapure water for 8 years. The ions produced during schreibersite corrosion (phosphite, hypophosphate, pyrophosphate, and phosphate) are stable and persistent in aqueous solution over this timescale. These results were also compared with the short-term corrosion reactions of the meteoritic mineral schreibersite’s synthetic analog Fe3P in aqueous and non-aqueous solutions (ultrapure water and formamide). This finding suggests that the reduced-oxidation-state phosphorus (P) compounds including phosphite could be ubiquitous and stable on the early Earth over a long span of time and such compounds could be readily available on the early Earth. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
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20 pages, 5305 KiB  
Article
Novel Apparatuses for Incorporating Natural Selection Processes into Origins-of-Life Experiments to Produce Adaptively Evolving Chemical Ecosystems
by Robert Root-Bernstein and Adam W. Brown
Life 2022, 12(10), 1508; https://doi.org/10.3390/life12101508 - 28 Sep 2022
Cited by 4 | Viewed by 1593
Abstract
Origins-of-life chemical experiments usually aim to produce specific chemical end-products such as amino acids, nucleic acids or sugars. The resulting chemical systems do not evolve or adapt because they lack natural selection processes. We have modified Miller origins-of-life apparatuses to incorporate several natural, [...] Read more.
Origins-of-life chemical experiments usually aim to produce specific chemical end-products such as amino acids, nucleic acids or sugars. The resulting chemical systems do not evolve or adapt because they lack natural selection processes. We have modified Miller origins-of-life apparatuses to incorporate several natural, prebiotic physicochemical selection factors that can be tested individually or in tandem: freezing-thawing cycles; drying-wetting cycles; ultraviolet light-dark cycles; and catalytic surfaces such as clays or minerals. Each process is already known to drive important origins-of-life chemical reactions such as the production of peptides and synthesis of nucleic acid bases and each can also destroy various reactants and products, resulting selection within the chemical system. No previous apparatus has permitted all of these selection processes to work together. Continuous synthesis and selection of products can be carried out over many months because the apparatuses can be re-gassed. Thus, long-term chemical evolution of chemical ecosystems under various combinations of natural selection may be explored for the first time. We argue that it is time to begin experimenting with the long-term effects of such prebiotic natural selection processes because they may have aided biotic life to emerge by taming the combinatorial chemical explosion that results from unbounded chemical syntheses. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
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Review

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18 pages, 1708 KiB  
Review
Prebiotic Chemistry Experiments Using Microfluidic Devices
by Karen Melissa Lerin-Morales, Luis F. Olguín, Eva Mateo-Martí and María Colín-García
Life 2022, 12(10), 1665; https://doi.org/10.3390/life12101665 - 21 Oct 2022
Cited by 4 | Viewed by 1842
Abstract
Microfluidic devices are small tools mostly consisting of one or more channels, with dimensions between one and hundreds of microns, where small volumes of fluids are manipulated. They have extensive use in the biomedical and chemical fields; however, in prebiotic chemistry, they only [...] Read more.
Microfluidic devices are small tools mostly consisting of one or more channels, with dimensions between one and hundreds of microns, where small volumes of fluids are manipulated. They have extensive use in the biomedical and chemical fields; however, in prebiotic chemistry, they only have been employed recently. In prebiotic chemistry, just three types of microfluidic devices have been used: the first ones are Y-form devices with laminar co-flow, used to study the precipitation of minerals in hydrothermal vents systems; the second ones are microdroplet devices that can form small droplets capable of mimic cellular compartmentalization; and the last ones are devices with microchambers that recreate the microenvironment inside rock pores under hydrothermal conditions. In this review, we summarized the experiments in the field of prebiotic chemistry that employed microfluidic devices. The main idea is to incentivize their use and discuss their potential to perform novel experiments that could contribute to unraveling some prebiotic chemistry questions. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
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27 pages, 1533 KiB  
Review
A Physicochemical Consideration of Prebiotic Microenvironments for Self-Assembly and Prebiotic Chemistry
by Arpita Saha, Ruiqin Yi, Albert C. Fahrenbach, Anna Wang and Tony Z. Jia
Life 2022, 12(10), 1595; https://doi.org/10.3390/life12101595 - 13 Oct 2022
Cited by 7 | Viewed by 3364
Abstract
The origin of life on Earth required myriads of chemical and physical processes. These include the formation of the planet and its geological structures, the formation of the first primitive chemicals, reaction, and assembly of these primitive chemicals to form more complex or [...] Read more.
The origin of life on Earth required myriads of chemical and physical processes. These include the formation of the planet and its geological structures, the formation of the first primitive chemicals, reaction, and assembly of these primitive chemicals to form more complex or functional products and assemblies, and finally the formation of the first cells (or protocells) on early Earth, which eventually evolved into modern cells. Each of these processes presumably occurred within specific prebiotic reaction environments, which could have been diverse in physical and chemical properties. While there are resources that describe prebiotically plausible environments or nutrient availability, here, we attempt to aggregate the literature for the various physicochemical properties of different prebiotic reaction microenvironments on early Earth. We introduce a handful of properties that can be quantified through physical or chemical techniques. The values for these physicochemical properties, if they are known, are then presented for each reaction environment, giving the reader a sense of the environmental variability of such properties. Such a resource may be useful for prebiotic chemists to understand the range of conditions in each reaction environment, or to select the medium most applicable for their targeted reaction of interest for exploratory studies. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
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12 pages, 2852 KiB  
Review
Origins of Life Research: The Conundrum between Laboratory and Field Simulations of Messy Environments
by David Deamer
Life 2022, 12(9), 1429; https://doi.org/10.3390/life12091429 - 14 Sep 2022
Cited by 4 | Viewed by 2270
Abstract
Most experimental results that guide research related to the origin of life are from laboratory simulations of the early Earth conditions. In the laboratory, emphasis is placed on the purity of reagents and carefully controlled conditions, so there is a natural tendency to [...] Read more.
Most experimental results that guide research related to the origin of life are from laboratory simulations of the early Earth conditions. In the laboratory, emphasis is placed on the purity of reagents and carefully controlled conditions, so there is a natural tendency to reject impurities and lack of control. However, life did not originate in laboratory conditions; therefore, we should take into consideration multiple factors that are likely to have contributed to the environmental complexity of the early Earth. This essay describes eight physical and biophysical factors that spontaneously resolve aqueous dispersions of ionic and organic solutes mixed with mineral particles and thereby promote specific chemical reactions required for life to begin. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
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18 pages, 964 KiB  
Review
Some Factors from Theory, Simulation, Experiment and Proteomes in the Current Biosphere Supporting Deep Oceans as the Location of the Origin of Terrestrial Life
by J. W. Halley
Life 2022, 12(9), 1330; https://doi.org/10.3390/life12091330 - 28 Aug 2022
Cited by 1 | Viewed by 1470
Abstract
Some standard arguments are reviewed supporting deep ocean trenches as a likely location for the origin of terrestrial life. An analysis of proteomes of contemporary prokaryotes carried out by this group is cited as supporting evidence, indicating that the original proteins were formed [...] Read more.
Some standard arguments are reviewed supporting deep ocean trenches as a likely location for the origin of terrestrial life. An analysis of proteomes of contemporary prokaryotes carried out by this group is cited as supporting evidence, indicating that the original proteins were formed by quenching from temperatures close to the boiling point of water. Coarse-grained simulations of the network formation process which agree quite well with experiments of such quenches both in drying and rapid fluid emission from a hot to a cold fluid are also described and cited as support for such a scenario. We suggest further experiments, observations and theoretical and simulation work to explore this hypothesis. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
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Other

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10 pages, 254 KiB  
Opinion
Distinguishing Biotic vs. Abiotic Origins of ‘Bio’signatures: Clues from Messy Prebiotic Chemistry for Detection of Life in the Universe
by Niraja V. Bapat and Sudha Rajamani
Life 2023, 13(3), 766; https://doi.org/10.3390/life13030766 - 13 Mar 2023
Viewed by 2298
Abstract
It is not a stretch to say that the search for extraterrestrial life is possibly the biggest of the cosmic endeavors that humankind has embarked upon. With the continued discovery of several Earth-like exoplanets, the hope of detecting potential biosignatures is multiplying amongst [...] Read more.
It is not a stretch to say that the search for extraterrestrial life is possibly the biggest of the cosmic endeavors that humankind has embarked upon. With the continued discovery of several Earth-like exoplanets, the hope of detecting potential biosignatures is multiplying amongst researchers in the astrobiology community. However, to be able to discern these signatures as being truly of biological origin, we also need to consider their probable abiotic origin. The field of prebiotic chemistry, which is aimed at understanding enzyme-free chemical syntheses of biologically relevant molecules, could particularly aid in this regard. Specifically, certain peculiar characteristics of prebiotically pertinent messy chemical reactions, including diverse and racemic product yields and lower synthesis efficiencies, can be utilized in analyzing whether a perceived ‘signature of life’ could possibly have chemical origins. The knowledge gathered from understanding the transition from chemistry to biology during the origin of life could be used for creating a library of abiotically synthesized biologically relevant organic molecules. This can then be employed in designing, standardizing, and testing mission-specific instruments/analysis systems, while also enabling the effective targeting of exoplanets with potentially ‘ongoing’ molecular evolutionary processes for robust detection of life in future explorative endeavors. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
18 pages, 3082 KiB  
Hypothesis
How Did Life Emerge in Chemically Complex Messy Environments?
by Kenji Ikehara
Life 2022, 12(9), 1319; https://doi.org/10.3390/life12091319 - 26 Aug 2022
Viewed by 2858
Abstract
One of the problems that make it difficult to solve the mystery of the origin of life is determining how life emerged in chemically complex messy environments on primitive Earth. In this article, the “chemically complex messy environments” that are focused on are [...] Read more.
One of the problems that make it difficult to solve the mystery of the origin of life is determining how life emerged in chemically complex messy environments on primitive Earth. In this article, the “chemically complex messy environments” that are focused on are a mixed state of various organic compounds produced via prebiotic means and accumulated on primitive earth. The five factors described below are thought to have contributed to opening the way for the emergence of life: (1) A characteristic inherent in [GADV]-amino acids, which are easily produced via prebiotic means. [GADV] stands for four amino acids, Gly [G], Ala [A], Asp [D] and Val [V], which are indicated by a one-letter symbol. (2) The protein 0th-order structure or a [GADV]-amino acid composition generating water-soluble globular protein with some flexibility, which can be produced even by the random joining of [GADV]-amino acids. (3) The formation of versatile [GADV]-microspheres, which can grow, divide and proliferate even without a genetic system, was the emergence of proto-life. (4) The [GADV]-microspheres with a higher proliferation ability than others were able to be selected. Proto-Darwin evolution made it possible to proceed forward to the creation of a core life system composed of the (GNC)n gene, anticodon stem-loop tRNA or AntiC-SL tRNA (GNC genetic code), and [GADV]-protein. (5) Eventually, the first genuine life with a core life system emerged. Thus, the formation processes of [GADV]-protein and the (GNC)n gene in chemically complex messy environments were the steps to the emergence of genuine life. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
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10 pages, 2590 KiB  
Concept Paper
Spontaneous Formation of Functional Structures in Messy Environments
by Christian Mayer
Life 2022, 12(5), 720; https://doi.org/10.3390/life12050720 - 11 May 2022
Cited by 4 | Viewed by 2447
Abstract
Even though prebiotic chemistry initially deals with simple molecules, its composition rapidly gains complexity with oligomerization. Starting with, e.g., 20 monomers (such as the 20 proteinogenic amino acids), we expect 400 different dimers, 3,200,000 pentamers, or more than 1013 decamers. Hence, the [...] Read more.
Even though prebiotic chemistry initially deals with simple molecules, its composition rapidly gains complexity with oligomerization. Starting with, e.g., 20 monomers (such as the 20 proteinogenic amino acids), we expect 400 different dimers, 3,200,000 pentamers, or more than 1013 decamers. Hence, the starting conditions are very messy but also form a very powerful pool of potentially functional oligomers. A selecting structure (a “selector” such as membrane multilayers or vesicles) may pick and accumulate those molecules from the pool that fulfill a simple function (such as the suitability to integrate into a bilayer membrane). If this “selector” is, in turn, subject to a superimposed selection in a periodic process, the accumulated oligomers may be further trimmed to fulfill more complex functions, which improve the survival rate of the selectors. Successful oligomers will be passed from generation to generation and further improved in subsequent steps. After thousands of generations, the selector, together with its integrated oligomers, can form a functional unit of considerable order and complexity. The actual power of this process of random formation and selection has already been shown in laboratory experiments. In this concept paper, earlier results are summarized and brought into a new context. Full article
(This article belongs to the Special Issue Origin of Life in Chemically Complex Messy Environments)
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