Where Did Life Begin? Testing Ideas in Prebiotic Analogue Conditions

Deamer, David W.

doi:10.3390/life11020134

Cited by 25 publications

(27 citation statements)

References 17 publications

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“…The current knowledge about the formation of HCN-derived polymers shows that their features depend on synthesis conditions, including concentration, temperature, presence of oxygen, time of reaction, and raw material [ 11 , 46 , 48 , 53 , 54 , 55 , 69 , 72 ]. Alkaline hydrothermal systems have been pointed out as very versatile and crucial environments for chemical evolution and, eventually, for origin of life scenarios [ 38 , 39 , 40 , 45 , 90 , 91 , 92 , 93 , 94 , 95 ]. Considering the new perspectives of prebiotic chemistry (that suggest to take into account the dynamism of environments, as well as the interactions among their geochemical variables; [ 29 , 46 , 96 ]), we tested the role of serpentinite during the polymerization of HCN as a first approximation of a simple simulation of an alkaline hydrothermal system.…”

Section: Outlook On Studies About Prebiotic Molecular Complexitymentioning

confidence: 99%

A Lizardite–HCN Interaction Leading the Increasing of Molecular Complexity in an Alkaline Hydrothermal Scenario: Implications for Origin of Life Studies

Villafañe-Barajas

Ruíz-Bermejo

Rayo-Pizarroso

et al. 2021

Life

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Hydrogen cyanide, HCN, is considered a fundamental molecule in chemical evolution. The named HCN polymers have been suggested as precursors of important bioorganics. Some novel researches have focused on the role of mineral surfaces in the hydrolysis and/or polymerization of cyanide species, but until now, their role has been unclear. Understanding the role of minerals in chemical evolution processes is crucial because minerals undoubtedly interacted with the organic molecules formed on the early Earth by different process. Therefore, we simulated the probable interactions between HCN and a serpentinite-hosted alkaline hydrothermal system. We studied the effect of serpentinite during the thermolysis of HCN at basic conditions (i.e., HCN 0.15 M, 50 h, 100 °C, pH > 10). The HCN-derived thermal polymer and supernatant formed after treatment were analyzed by several complementary analytical techniques. The results obtained suggest that: I) the mineral surfaces can act as mediators in the mechanisms of organic molecule production such as the polymerization of HCN; II) the thermal and physicochemical properties of the HCN polymer produced are affected by the presence of the mineral surface; and III) serpentinite seems to inhibit the formation of bioorganic molecules compared with the control (without mineral).

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Section: Outlook On Studies About Prebiotic Molecular Complexitymentioning

confidence: 99%

A Lizardite–HCN Interaction Leading the Increasing of Molecular Complexity in an Alkaline Hydrothermal Scenario: Implications for Origin of Life Studies

Villafañe-Barajas

Ruíz-Bermejo

Rayo-Pizarroso

et al. 2021

Life

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“…A body of theoretical, experimental, and field observations suggest that subaerial restricted basins could have accumulated high amphiphile concentrations, which then self-assembled into prebiotic compartments (Figure 2a-iii) [8,[23][24][25][26]. Accumulation could have occurred directly at the water surface, owing to the mechanisms described earlier in this paper, or across evaporative cycles [8,25,27].…”

Section: Prebiotic Plausibility Of Scum Layersmentioning

confidence: 83%

Scum of the Earth: a hypothesis for prebiotic multi-compartmentalised environments}

Walton¹,

Shorttle²

2021

Preprint

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Compartmentalisation by bioenergetic membranes is a universal feature of life. The eventual compartmentalisation of prebiotic systems is therefore often argued to comprise a key step during the origin of life. Compartments may have been active participants in prebiotic chemistry, concentrating and spatially organising key reactants. However, most prebiotically plausible compartments are leaky or unstable, limiting their utility. Here, we develop a new hypothesis for an origin of life environment, that capitalises upon, and mitigates the limitations of, prebiotic compartments: multi-compartmentalised layers in the near surface environment --- a 'scum'. Scum-type environments benefit from many of the same ensemble-based advantages as microbial biofilms. In particular, scum layers mediate diffusion with the wider environment, favouring preservation and sharing of early informational molecules, along with the selective concentration of compatible prebiotic compounds. Biofilms are among the earliest traces imprinted by life in the rock record: we contend that prebiotic equivalents of these environments deserve future experimental investigation.

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“…In contrast, the AVT is built solidly in acknowledgement of the geological, geochemical and geophysical conditions on the early Earth as assembled by countless scientists. The retrodicted mineralogy of the early Earth cannot be dismissed merely by writing “it is uncertain whether these (minerals) were available on the prebiotic Earth” [ 74 ]. To counter this statement, we present in Table 1 all the evidence pertaining to our contention that the rocky surface of the Earth was always submerged in the roiling Hadean Ocean.…”

Section: Avt Critiques: the False Requiemmentioning

confidence: 99%

The “Water Problem”(sic), the Illusory Pond and Life’s Submarine Emergence—A Review

Russell

2021

Life

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The assumption that there was a “water problem” at the emergence of life—that the Hadean Ocean was simply too wet and salty for life to have emerged in it—is here subjected to geological and experimental “reality checks”. The “warm little pond” that would take the place of the submarine alkaline vent theory (AVT), as recently extolled in the journal Nature, flies in the face of decades of geological, microbiological and evolutionary research and reasoning. To the present author, the evidence refuting the warm little pond scheme is overwhelming given the facts that (i) the early Earth was a water world, (ii) its all-enveloping ocean was never less than 4 km deep, (iii) there were no figurative “Icelands” or “Hawaiis”, nor even an “Ontong Java” then because (iv) the solidifying magma ocean beneath was still too mushy to support such salient loadings on the oceanic crust. In place of the supposed warm little pond, we offer a well-protected mineral mound precipitated at a submarine alkaline vent as life’s womb: in place of lipid membranes, we suggest peptides; we replace poisonous cyanide with ammonium and hydrazine; instead of deleterious radiation we have the appropriate life-giving redox and pH disequilibria; and in place of messy chemistry we offer the potential for life’s emergence from the simplest of geochemically available molecules and ions focused at a submarine alkaline vent in the Hadean—specifically within the nano-confined flexible and redox active interlayer walls of the mixed-valent double layer oxyhydroxide mineral, fougerite/green rust comprising much of that mound.

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Where Did Life Begin? Testing Ideas in Prebiotic Analogue Conditions

Cited by 25 publications

References 17 publications

A Lizardite–HCN Interaction Leading the Increasing of Molecular Complexity in an Alkaline Hydrothermal Scenario: Implications for Origin of Life Studies

A Lizardite–HCN Interaction Leading the Increasing of Molecular Complexity in an Alkaline Hydrothermal Scenario: Implications for Origin of Life Studies

Scum of the Earth: a hypothesis for prebiotic multi-compartmentalised environments}

The “Water Problem”(sic), the Illusory Pond and Life’s Submarine Emergence—A Review

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