Incubating Life: Prebiotic Sources of Organics for the Origin of Life

Dalai, Punam; Kaddour, Hussein; Sahai, Nita

doi:10.2113/gselements.12.6.401

Cited by 34 publications

(28 citation statements)

References 26 publications

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“…Organic acids are likely to have been present throughout the Earth’s history through abiotic or biotic synthesis pathways (see, e.g., refs. 36 , 37 ) and may have played important roles in the weathering 38 of poorly soluble transition metals.…”

Section: Introductionmentioning

confidence: 99%

Redox-independent chromium isotope fractionation induced by ligand-promoted dissolution

et al. 2017

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The chromium (Cr) isotope system has emerged as a potential proxy for tracing the Earth’s atmospheric evolution based on a redox-dependent framework for Cr mobilization and isotope fractionation. Although studies have demonstrated that redox-independent pathways can also mobilize Cr, no quantitative constraints exist on the associated isotope fractionations. Here we survey the effects of common environmental ligands on the dissolution of Cr(III)-(oxy)hydroxide solids and associated Cr isotope fractionation. For a variety of organic acids and siderophores, δ53Cr values of dissolved Cr(III) are −0.27 to 1.23‰, within the range of previously observed Cr isotope signatures in rock records linked to Cr redox cycling. Thus, ligand-promoted dissolution of Cr-containing solids, a redox-independent process, must be taken into account when using sedimentary Cr isotope signatures to diagnose atmospheric oxygen levels. This work provides a step towards establishing a more robust framework for using Cr isotopes to track the evolution of the Earth’s atmosphere.

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Section: Introductionmentioning

confidence: 99%

Redox-independent chromium isotope fractionation induced by ligand-promoted dissolution

et al. 2017

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“…Single chain amphiphiles (SCAs), mainly fatty acids and fatty alcohols, have been employed extensively in the literature as model protocell membranes in origins of life studies 4 5 6 7 8 because it is believed that abiotic phospholipid synthesis would have been too difficult. Also, SCAs have been isolated from carbonaceous chondrites and synthesized under hydrothermal conditions, which suggests that they may have been present on early Earth 9 10 11 12 . Inorganic solid-lipid interactions are also important in a diverse array of fields, for example, in petroleum recovery, drug delivery, improving biocompatibility of biomaterial surfaces by deposition of phospholipid bilayers, clean energy applications and cytotoxicity of nanoparticles to human and bacterial cells.…”

mentioning

confidence: 99%

Mineral Surface Chemistry and Nanoparticle-aggregation Control Membrane Self-Assembly

Sahai

Kaddour

Dalai

et al. 2017

Sci Rep

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The self-assembly of lipid bilayer membranes to enclose functional biomolecules, thus defining a “protocell,” was a seminal moment in the emergence of life on Earth and likely occurred at the micro-environment of the mineral-water interface. Mineral-lipid interactions are also relevant in biomedical, industrial and technological processes. Yet, no structure-activity relationships (SARs) have been identified to predict lipid self-assembly at mineral surfaces. Here we examined the influence of minerals on the self-assembly and survival of vesicles composed of single chain amphiphiles as model protocell membranes. The apparent critical vesicle concentration (CVC) increased in the presence of positively-charged nanoparticulate minerals at high loadings (mg/mL) suggesting unfavorable membrane self-assembly in such situations. Above the CVC, initial vesicle formation rates were faster in the presence of minerals. Rates were correlated with the mineral’s isoelectric point (IEP) and reactive surface area. The IEP depends on the crystal structure, chemical composition and surface hydration. Thus, membrane self-assembly showed rational dependence on fundamental mineral properties. Once formed, membrane permeability (integrity) was unaffected by minerals. Suggesting that, protocells could have survived on rock surfaces. These SARs may help predict the formation and survival of protocell membranes on early Earth and other rocky planets, and amphiphile-mineral interactions in diverse other phenomena.

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“…Rossi et al, 2008;Andrews-Hanna et al, 2010;Franchi et al, 2014;Pondrelli et al, 2015;Pozzobon et al, 2019) boosted the interest in microbial mats living in spring deposits formed under extreme evaporitic and hypersaline conditions. Recent discoveries have revealed that hypersaline conditions may promote polymerization of prebiotic molecules and therefore can be suitable incubators for life (Dalai et al, 2016). In this regard the GAB provides unparalleled opportunity for comparison of Martian layered evaporitic sediments with terrestrial counterparts because of their complex formation that involves groundwater upwelling, springs, evaporative conditions, high UV radiation and evidence of organomineralization (e.g.…”

Section: Implications For Extra-terrestrial Research For Lifementioning

confidence: 99%

Crystallization pathways in the Great Artesian Basin (Australia) spring mound carbonates: Implications for life signatures on Earth and beyond

Franchi

Frisia

2020

Sedimentology

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Recent studies of continental carbonates revealed that carbonates with similar fabrics can be formed either by biotic, biologically‐induced, biologically‐influenced or purely abiotic processes, or a combination of all. The aim of this research is to advance knowledge on the formation of carbonates precipitated (or diagenetically altered) in extreme, continental environments by studying biotic versus abiotic mechanisms of crystallization, and to contribute to the astrobiology debate around terrestrial analogues of Martian extreme environments. Both fossil (upper Pleistocene to Holocene) and active carbonate spring mounds from the Great Artesian Basin (South Australia) have been investigated. These carbonates consist of low‐Mg to high‐Mg calcite tufa. Four facies have been described: (i) carbonate mudstone/wackestone; (ii) phytohermal framestone/boundstone; (iii) micrite boundstone; and (iv) coarsely crystalline boundstone. The presence of filaments encrusted by micrite, rich in organic compounds, including ultraviolet‐protectants, in phytohermal framestone/boundstone and micrite boundstone is clear evidence of the existence of microbial mats at the time of deposition. In contrast, peloidal micrite, despite commonly being considered a microbial precipitate, is not directly associated with filaments in the Great Artesian Basin mounds. It has probably formed from nanocrystal aggregation on colloid particulate. Thus, where biofilms have been documented, it is likely that bacteria catalyzed the development of fabrics. It is less certain that microbes induced calcium carbonate precipitation elsewhere. Trace elements, including rare earth element distribution from laminated facies, highlight strongly evaporative settings (for example, high Li contents). Carbon dioxide degassing and evaporation are two of the main drivers for an increase in fluid alkalinity, resulting in precipitation of carbonates. Hence, although the growth of certain fabrics is fostered by the presence of microbial mats, the formation of carbonate crystals might be independent from it and mainly driven by extrinsic factors. More generally, biological processes may be responsible for fabric and facies development in micritic boundstone whilst micrite nucleation and growth are driven by abiotic factors. Non‐classical crystallization pathways (aggregation and fusion of nanoparticles from nucleation clusters) may be more common than previously thought in spring carbonate and this should be carefully considered to avoid misinterpretation of certain fabrics as by‐products of life. It is proposed here that the term ‘organic‐compound catalyzed mineralization’ should be used for crystal growth in the presence of organic compounds when dealing with astrobiological problems. This term would account for the possibility of multiple crystallization pathways (including non‐classical crystallization) that occurred directly from an aqueous solution without the direct influence of microbial mats.

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Incubating Life: Prebiotic Sources of Organics for the Origin of Life

Cited by 34 publications

References 26 publications

Redox-independent chromium isotope fractionation induced by ligand-promoted dissolution

Redox-independent chromium isotope fractionation induced by ligand-promoted dissolution

Mineral Surface Chemistry and Nanoparticle-aggregation Control Membrane Self-Assembly

Crystallization pathways in the Great Artesian Basin (Australia) spring mound carbonates: Implications for life signatures on Earth and beyond

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