PRIMORDIAL LIFE

2018 ◽  
pp. 29-29
Keyword(s):  
Primordial Life

Laboratory simulation of UV irradiation from the Sun on amino acids. I: irradiation of tyrosine

2007 ◽  
Vol 6 (2) ◽  
pp. 123-129 ◽  
Author(s):  
F. Scappini ◽  
F. Casadei ◽  
R. Zamboni ◽  
S. Monti ◽  
P. Giorgianni ◽  
...  
Keyword(s):  
Amino Acids ◽  
Uv Irradiation ◽  
Degradation Products ◽  
Building Blocks ◽  
Laboratory Simulation ◽  
The Sun ◽  
Primitive Earth ◽  
Laboratory Results ◽  
Building Capability ◽  
Primordial Life

AbstractThe effects of ultraviolet (UV) irradiation on water solutions of tyrosine (HO—C6H4—CH2—CHNH2—COOH) have been investigated using a Xe lamp in the region 200–800 nm. This is a step in laboratory simulation towards reproducing the action of the Solar radiation on the building blocks of life, specifically α-amino acids, in the primitive Earth anoxic conditions. Results are presented showing the photostability of tyrosine against different UV doses. Degradation products partly maintain life building capability and partly do not. A tendency towards structure complexification was observed. The analysis of the irradiated tyrosine solutions was conducted using various spectroscopic and analytic techniques. The laboratory results are discussed in the light of a primordial life-emerging scenario.

Arsenic and primordial life

2014 ◽  
Vol 7 (11) ◽  
pp. 785-786 ◽  
Author(s):  
Thomas R. Kulp
Keyword(s):  
Primordial Life

scholarly journals Unique metabolic strategies in Hadean analogues reveal hints for primordial physiology

2021 ◽  
Author(s):  
Masaru Konishi Nobu ◽  
Ryosuke Nakai ◽  
Satoshi Tamazawa ◽  
Hiroshi Mori ◽  
Atsushi Toyoda ◽  
...  
Keyword(s):  
Early Earth ◽  
Carbon Compounds ◽  
Glycine Reductase ◽  
Genes Encoding ◽  
Metabolic Strategies ◽  
Primordial Life ◽  
Core Metabolism ◽  
New View

Primordial microorganisms are postulated to have emerged in H2-rich alkaline Hadean serpentinite-hosted environments with homoacetogenesis as a core metabolism. However, investigation of two modern serpentinization-active analogues of early Earth reveals that conventional H2-/CO2-dependent homoacetogenesis is thermodynamically unfavorable in situ due to picomolar CO2 levels. Through metagenomics and thermodynamics, we discover unique taxa capable of metabolism adapted to the habitat. This included a novel deep-branching phylum, "Ca. Lithoacetigenota", that exclusively inhabits Hadean analogues and harbors genes encoding alternative modes of H2-utilizing lithotrophy. Rather than CO2, these metabolisms utilize reduced carbon compounds detected in situ presumably serpentinization-derived: formate and glycine. The former employs a partial homoacetogenesis pathway and the latter a distinct pathway mediated by a rare selenoprotein - the glycine reductase. A survey of serpentinite-hosted system microbiomes shows that glycine reductases are diverse and nearly ubiquitous in Hadean analogues. "Ca. Lithoacetigenota" glycine reductases represent a basal lineage, suggesting that catabolic glycine reduction is an ancient bacterial innovation for gaining energy from geogenic H2 even under serpentinization-associated hyperalkaline, CO2-poor conditions. This draws remarkable parallels with ancestral archaeal H2-driven methyl-reducing methanogenesis recently proposed. Unique non-CO2-reducing metabolic strategies presented here may provide a new view into metabolisms that supported primordial life and the diversification of LUCA towards Archaea and Bacteria.

scholarly journals A Living Spatial Movement of Relation. Reconceptualising Ricœur’s Oneself as Another and Heidegger’s Being and Time

2021 ◽  
Vol 11 (2) ◽  
pp. 111-132
Author(s):  
Paul Downes
Keyword(s):  
The Other ◽  
Being And Time ◽  
One Dimension ◽  
Living Well ◽  
Living Space ◽  
Spatial Movement ◽  
Embodied Subjectivity ◽  
Spatial Discourse ◽  
Primordial Life

Beyond the disparate and mainly fleeting references to life in Ricoeur’s Oneself as Another, whether as life as power, living well and with others, or as Ricoeur’s attempt to develop a concept of embodied subjectivity as flesh, which is presumably living flesh, not dead flesh, a further and arguably primordial life principle needs emphasis, namely, living space. Ricoeur’s recognition of the vital significance of space primordiality, as a pivotal dimension that is even prior to language, offers a significant conceptual leap in Ricoeur’s later work, Oneself as Another. Ricoeur’s proposed ontology of the flesh is one dimension towards expression of an authentic phenomenology of spatiality, though not necessarily the only one. Building upon but going beyond Ricoeur, the article explores concentric and diametric spatial interplay in relation to the early Heidegger’s existential spatiality, Angst and care, as candidate living spatial movements. This proposed primordial spatial discourse re-examines Ricoeur’s conatus as power to act, and his quest for a structure of relation to the other that is not closure, separation, or diametric opposition.

The primordial life of DNA dynamic networks

2020 ◽  
Vol 3 (11) ◽  
pp. 865-866
Author(s):  
Lena J. Winat ◽  
Barbara Saccà
Keyword(s):  
Dynamic Networks ◽  
Primordial Life

scholarly journals Presence of water on exomoons orbiting free-floating planets: a case study

2021 ◽  
pp. 1-12
Author(s):  
Patricio Javier Ávila ◽  
Tommaso Grassi ◽  
Stefano Bovino ◽  
Andrea Chiavassa ◽  
Barbara Ercolano ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Liquid Water ◽  
Galactic Centre ◽  
Orbital Parameters ◽  
Potential Development ◽  
Primordial Life ◽  
Thermal Stability Of ◽  
Final Amount

Abstract A free-floating planet (FFP) is a planetary-mass object that orbits around a non-stellar massive object (e.g. a brown dwarf) or around the Galactic Centre. The presence of exomoons orbiting FFPs has been theoretically predicted by several models. Under specific conditions, these moons are able to retain an atmosphere capable of ensuring the long-term thermal stability of liquid water on their surface. We model this environment with a one-dimensional radiative-convective code coupled to a gas-phase chemical network including cosmic rays and ion-neutral reactions. We find that, under specific conditions and assuming stable orbital parameters over time, liquid water can be formed on the surface of the exomoon. The final amount of water for an Earth-mass exomoon is smaller than the amount of water in Earth oceans, but enough to host the potential development of primordial life. The chemical equilibrium time-scale is controlled by cosmic rays, the main ionization driver in our model of the exomoon atmosphere.

scholarly journals Cyclophosphates, a new class of native phosphorus compounds, and some insights into prebiotic phosphorylation on early Earth

Geology ◽  
2020 ◽  
Vol 49 (4) ◽  
pp. 382-386
Author(s):  
Sergey N. Britvin ◽  
Michail N. Murashko ◽  
Yevgeny Vapnik ◽  
Natalia S. Vlasenko ◽  
Maria G. Krzhizhanovskaya ◽  
...  
Keyword(s):  
Ring Opening ◽  
Dead Sea ◽  
Phosphorus Compounds ◽  
Early Earth ◽  
Terrestrial Environment ◽  
New Class ◽  
Dead Sea Basin ◽  
Hydrolytic Decomposition ◽  
Phosphate Species ◽  
Primordial Life

Abstract Cyclophosphates are a class of energy-rich compounds whose hydrolytic decomposition (ring opening) liberates energy that is sufficient for initiation of biomimetic phosphorylation reactions. Because of that, cyclophosphates might be considered as a likely source of reactive prebiotic phosphorus on early Earth. A major obstacle toward adoption of this hypothesis is that cyclophosphates have so far not been encountered in nature. We herein report on the discovery of these minerals in the terrestrial environment, at the Dead Sea basin in Israel. Cyclophosphates represent the most condensed phosphate species known in nature. A pathway for cyclophosphate geosynthesis is herein proposed, involving simple pyrolytic oxidation of terrestrial phosphides. Discovery of natural cyclophosphates opens new opportunities for modeling prebiotic phosphorylation reactions that resulted in the emergence of primordial life on our planet.

The Wonderland of primordial life

Nature ◽  
2000 ◽  
Vol 405 (6787) ◽  
pp. 619-620 ◽  
Author(s):  
John Godfrey
Keyword(s):  
Primordial Life

The physiology and evolution of microbial selenium metabolism

Metallomics ◽  
2021 ◽  
Author(s):  
Michael Wells ◽  
Partha Basu ◽  
John F Stolz
Keyword(s):  
Current Knowledge ◽  
Anaerobic Respiration ◽  
Physiological Adaptation ◽  
Elemental Selenium ◽  
Comprehensive Overview ◽  
Selenium Metabolism ◽  
Universal Common Ancestor ◽  
Domains Of Life ◽  
Metabolic Reactions ◽  
Primordial Life

Abstract Selenium is an essential trace element whose compounds are widely metabolized by organisms from all three domains of life. Moreover, phylogenetic evidence indicates that selenium species, along with iron, molybdenum, tungsten, and nickel, were metabolized by the last universal common ancestor (LUCA) of all cellular lineages, primarily for the synthesis of the 21st amino acid selenocysteine. Thus, selenium metabolism is both environmentally ubiquitous and a physiological adaptation of primordial life. Selenium metabolic reactions comprise reductive transformations both for assimilation into macromolecules and dissimilatory reduction of selenium oxyanions and elemental selenium during anaerobic respiration. This review offers a comprehensive overview of the physiology and evolution of both assimilatory and dissimilatory selenium metabolism in bacteria and archaea, highlighting mechanisms of selenium respiration. This includes a thorough discussion of our current knowledge of the physiology of selenocysteine synthesis and incorporation into proteins in bacteria obtained from structural biology. Additionally, this is the first comprehensive discussion in a review of the incorporation of selenium into the tRNA nucleoside 5-methylaminomethyl-2-selenouridine and as an inorganic cofactor in certain molybdenum hydroxylase enzymes. Throughout, conserved mechanisms and derived features of selenium metabolism in both domains are emphasized and discussed within the context of the global selenium biogeochemical cycle.

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