Putative prebiotics

Just over fifty years ago, a major breakthrough occurred the celebrated Miller spark tube experiment (Miller, 1953), in which sparks (simulating electric storms) in a putative prebiotic atmosphere of methane, ammonia, dihydrogen, and water produced, under recycling conditions, a complex mixture of products containing in particular a variety of a-amino acids (identical to those used by all living organisms) (Miller, 1953). 

Several institutes throughout the world immediately began to carry out experiments on prebiotic chemistry. At this point, we need to realize that the prebiotic synthesis of protein building blocks is only a first step towards solving the biogenesis problem. Put simply, it is a method for making bricks which will later be used in building a multi-storey office block ... 

Was Nature s selection of these stereochemical structures a random event, or was it the consequence of determinate processes Although the presence of amino adds and other organic molecules on primitive Earth has been attributed to both endogenous and exogenous sources, [5,6] the origin of the chiral bias of prebiotic molecules remains a fundamental mystery. A mystery perhaps even more central to the origin of life is the mechanism that brought into dominance and survival any putative small chiral molecular excess on early Earth. 

One of the super fruit signature nutrients with broad health effects— prebiotic dietary fiber (also called soluble or viscous fiber)—is manufactured out of nearly every pill or capsule, unless purposely put back in. Don t miss out on the important health values of prebiotic fiber. 

Against this background, I will examine how coarsely tuned these simultaneous effects can be - that is, what variations can occur and what flexibility does this enable I shall finish close to where I started, with a confession that major problems remain and gaps in our current understanding exist. Put frankly and simply, nobody knows yet how life originated. As I concentrate on the fine- and coarse-tuning aspects of life, I will refer to some of the many detailed reviews of the topic of prebiotic chemistry for more specific discussions (see, for example, Miller and Orgel, 1974 Sutherland and Whitfield, 1997). 

Put more simply, when considering prebiotic selection and evolution in the context of the origin of life, the enormously powerful force of water must never be underestimated. As all life is based on water, all molecules in living systems interact with it, and water likely has driven molecular evolution from the very beginning, here on earth or plausibly elsewhere in the universe - or multiverse. 

Pestunova O, Simonov A, Snytnikov V, Stoyanovsky V, Parmon V Putative mechanism of the sugar formation on prebiotic Earth initiated by UV-radiation. Adv Space Res 2005, 36(2) 214—219. 

The synthesis of RNA in extant biology, however, still relies upon the participation of proteins. The protein-fiTee de novo synthesis of RNA in a prebiotic reaction has yet to be demonstrated after several decades of effort (5). Many researchers have therefore concluded that RNA was not the first informational polymer of life. Rather, RNA was preceded by an RNA-Me polymer, or several generations of polymers, termed proto-RNAs, that were stracturally and functionally similar to RNA, but easier to assemble. Proto-RNA could have been comprised of different bases, sugars, and hnking molecules that were assembled through more thermodynamically and kinetically accessible pathways. Without the constraints of the current four RNA bases, ribose, and phosphate for the construction of an informational polymer, the possible composition of proto-RNAs seems limitless. However, tte existence of putative monomer units in the prebiotic chemical inventory for the assembly of proto-RNA would have been dictated by astro- and geochemical processes, paring down the set of molecules from which nature could select. 

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