Formation of Adenosine by Ultra-violet Irradiation of a Solution of Adenine and Ribose

Ponnamperuma, Cyril; Mariner, Ruth; Sagan, Carl

doi:10.1038/1981199a0

Cited by 43 publications

(15 citation statements)

References 15 publications

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“…Some of the most successful attempts to simulate primitive abiogenic reactions have been conducted under conditions that are compatible with reconstructed conditions at the geothermal fields of the anoxic Earth. These promising experiments include syntheses of biologically relevant compounds in formamide solutions (98)(99)(100)(101)(102)(103)(104)(105)(106)(107)(108)(111)(112)(113)(114)(115), photosynthesis/photoselection of natural nucleotides (120)(121)(122)133), montmorillonite-catalyzed formation of long RNA oligomers (118) and membrane vesicles (134), RNA polymerization in the eutectic phase in water-ice (135), abiotic UV photosynthesis of the tricarboxylic acid cycle intermediates at ZnS (83,84) and TiO 2 crystals (136), as well as UV-triggered recharging of ADP to ATP (137). Further experimental exploration of models that mimic the conditions at anoxic geothermal fields are expected to shed more light on precellular evolution.…”

Section: Discussionmentioning

confidence: 99%

Origin of first cells at terrestrial, anoxic geothermal fields

Mulkidjanian

Bychkov²,

Dibrova³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

369

336

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All cells contain much more potassium, phosphate, and transition metals than modern (or reconstructed primeval) oceans, lakes, or rivers. Cells maintain ion gradients by using sophisticated, energydependent membrane enzymes (membrane pumps) that are embedded in elaborate ion-tight membranes. The first cells could possess neither ion-tight membranes nor membrane pumps, so the concentrations of small inorganic molecules and ions within protocells and in their environment would equilibrate. Hence, the ion composition of modern cells might reflect the inorganic ion composition of the habitats of protocells. We attempted to reconstruct the "hatcheries" of the first cells by combining geochemical analysis with phylogenomic scrutiny of the inorganic ion requirements of universal components of modern cells. These ubiquitous, and by inference primordial, proteins and functional systems show affinity to and functional requirement for K + , Zn 2+ , Mn 2+, and phosphate. Thus, protocells must have evolved in habitats with a high K + /Na + ratio and relatively high concentrations of Zn, Mn, and phosphorous compounds. Geochemical reconstruction shows that the ionic composition conducive to the origin of cells could not have existed in marine settings but is compatible with emissions of vapor-dominated zones of inland geothermal systems. Under the anoxic, CO 2 -dominated primordial atmosphere, the chemistry of basins at geothermal fields would resemble the internal milieu of modern cells. The precellular stages of evolution might have transpired in shallow ponds of condensed and cooled geothermal vapor that were lined with porous silicate minerals mixed with metal sulfides and enriched in K + , Zn 2+, and phosphorous compounds.

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Section: Discussionmentioning

confidence: 99%

Origin of first cells at terrestrial, anoxic geothermal fields

Mulkidjanian

Bychkov²,

Dibrova³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

369

336

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“…In this case, yields may be considerably increased by augmenting the temperature (Ponnamperuma and Mack, 1965;de Graaf and Schwartz, 2005) or employing catalysts, such as enzymes.…”

Section: Abiogenic Synthesis Of the Molecules Of Lifementioning

confidence: 99%

Thermodynamic dissipation theory for the origin of life

Michaelian

2011

Earth Syst. Dynam.

168

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Abstract. Understanding the thermodynamic function of life may shed light on its origin. Life, as are all irreversible processes, is contingent on entropy production. Entropy production is a measure of the rate of the tendency of Nature to explore available microstates. The most important irreversible process generating entropy in the biosphere and, thus, facilitating this exploration, is the absorption and transformation of sunlight into heat. Here we hypothesize that life began, and persists today, as a catalyst for the absorption and dissipation of sunlight on the surface of Archean seas. The resulting heat could then be efficiently harvested by other irreversible processes such as the water cycle, hurricanes, and ocean and wind currents. RNA and DNA are the most efficient of all known molecules for absorbing the intense ultraviolet light that penetrated the dense early atmosphere and are remarkably rapid in transforming this light into heat in the presence of liquid water. From this perspective, the origin and evolution of life, inseparable from water and the water cycle, can be understood as resulting from the natural thermodynamic imperative of increasing the entropy production of the Earth in its interaction with its solar environment. A mechanism is proposed for the reproduction of RNA and DNA without the need for enzymes, promoted instead through UV light dissipation and diurnal temperature cycling of the Archean sea-surface.

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“…Irradiation of aqueous solutions of formaldehyde containing ammonium nitrate was found to yield glyoxal, presumably by dimerization of two formyl radicals CHO formed in the initial photochemical step (9). Also, UV-irradiation of dilute formaldehyde produc~ traces of ribose and deoxyribose (10). In the absence of oxygen, irradiation of dilute aqueous formaldehyde resulted in the formation of glyoxal and malonaldehyde (11).…”

mentioning

confidence: 99%