alpha-Hydroxy and alpha-amino acids under possible Hadean, volcanic origin-of-life conditions.
ABSTRACT To test the theory of a chemoautotrophic origin of life in a volcanic, hydrothermal setting, we explored mechanisms for the buildup of bio-organic compounds by carbon fixation on catalytic transition metal precipitates. We report the carbon monoxide-dependent formation of carbon-fixation products, including an ordered series of alpha-hydroxy and alpha-amino acids of the general formula R-CHA-COOH (where R is H, CH3,C2H5,orHOCH2 and A is OH or NH2) by carbon fixation at 80 degrees to 120 degrees C, catalyzed by nickel or nickel,iron precipitates with carbonyl, cyano, and methylthio ligands as carbon sources, with or without sulfido ligands. Calcium or magnesium hydroxide was added as a pH buffer. The results narrow the gap between biochemistry and volcanic geochemistry and open a new gateway for the exploration of a volcanic, hydrothermal origin of life.
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ABSTRACT: The extant genetic machinery revolves around three interrelated polymers: RNA, DNA and proteins. Two evolutionary views approach this vital connection from opposite perspectives. The RNA World theory posits that life began in a cold prebiotic broth of monomers with the de novo emergence of replicating RNA as functionally self-contained polymer and that subsequent evolution is characterized by RNA → DNA memory takeover and ribozyme → enzyme catalyst takeover. The FeS World theory posits that life began as an autotrophic metabolism in hot volcanic-hydrothermal fluids and evolved with organic products turning into ligands for transition metal catalysts thereby eliciting feedback and feed-forward effects. In this latter context it is posited that the three polymers of the genetic machinery essentially coevolved from monomers through oligomers to polymers, operating functionally first as ligands for ligand-accelerated transition metal catalysis with later addition of base stacking and base pairing, whereby the functional dichotomy between hereditary DNA with stability on geologic time scales and transient, catalytic RNA with stability on metabolic time scales existed since the dawn of the genetic machinery. Both approaches are assessed comparatively for chemical soundness.12/2014; 4(4):1050-91. DOI:10.3390/life4041050
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ABSTRACT: Gases provide a known mechanism of metal migration through cover and a potential sampling medium to explore through cover that is under-utilised and under-studied. Understanding how metals move through transported cover and their link to buried deposits is critical information for successful mineral exploration in many regions of the world including the well-endowed Yilgarn Craton of Western Australia. Here we employ metal and hydrocarbon soil gas collection methods to successfully predict the location of the underlying North Miitel Ni ore body. Laboratory experiments to replicate soil moisture, hypergeometric evaluation and variable spacing tests were used to verify the gaseous Ni signature. Soil gas hydrocarbon analysis also reported an unqualified, but positive result. Integrating this study with previous research on soil, regolith, groundwater and vegetation chemistry in the study area enabled a model of anomaly formation to be derived explaining the observed results and the contributions of weathering, hydromorphic, biotic, aeolian and gaseous dispersion mechanisms operating at the North Miitel site. Weathering and hydromorphic dispersion are responsible for lateral and minor vertical Ni migration at depth, aeolian Ni is dispersed laterally near the road, whereas vegetation is cycling Ni in the shallow soils only. Results indicate a gaseous migration of Ni is responsible for vertical migration through cover at this site and provides a viable target for exploration through cover.Geochemistry Exploration Environment Analysis 06/2013; 13(2):99-113. DOI:10.1144/geochem2012-131 · 1.20 Impact Factor