It is now widely held that the early Earth's atmosphere was likely neutral, dominated by N 2 ... more It is now widely held that the early Earth's atmosphere was likely neutral, dominated by N 2 and CO 2 . The synthesis of organic compounds by the action of electric discharges on neutral gas mixtures has been shown to be much less efficient than with reducing gas mixtures. We show here that contrary to previous findings, significant amounts of amino acids are produced under these conditions. The low yields found previously were likely the result of oxidation of the organic compounds during hydrolytic workup by nitrite and nitrate produced in the reactions. Addition of oxidation inhibitors prior to hydrolysis results in the recovery of several hundred times more amino acids than reported previously. Organic synthesis from neutral atmospheres may thus have depended as much on oceanic conditions as on the characteristics of the primitive atmosphere itself. These findings imply the need for a critical re-evaluation of the importance of such syntheses on the primitive Earth and other planetary bodies that, like Mars, may have been endowed with CO 2 and N 2 -rich atmospheres throughout most of their history.
and DEMOSS 1963) as no anthranilate synthetase could be detected in crude extracts of this mutant... more and DEMOSS 1963) as no anthranilate synthetase could be detected in crude extracts of this mutant. In addition, these same strains were tested for growth on a medium containing 20 pg/ml of anthranilic acid. None of them grew, showing that the suppressor did not restore PRA isomerase and InGP synthetase.
Physical chemistry chemical physics : PCCP, Jan 2, 2016
From a geochemical perspective, significant amounts of pure formamide (HCONH2) would have likely ... more From a geochemical perspective, significant amounts of pure formamide (HCONH2) would have likely been rare on the early Earth. There may have been mixed formamide-water solutions, but even in the presence of catalyst, solutions with >20 weight% water in formamide would not have produced significant amounts of prebiotic compounds. It might be feasible to produce relatively pure formamide by a rare occurrence of freezing formamide/water mixtures at temperatures lower than formamide's freezing point (2.55 °C) but greater than the freezing point of water. Because of the high density of formamide ice it would have sunk and accumulated at the bottom of the solution. If the remaining water froze on the surface of this ice, and was then removed by a sublimation-ablation process, a small amount of pure formamide ice might have been produced. In addition a recent report suggested that ∼85 weight% formamide could be prepared by a geochemical type of fractional distillation process, offe...
It is now widely held that the early Earth's atmosphere was likely neutral, dominated by N 2 ... more It is now widely held that the early Earth's atmosphere was likely neutral, dominated by N 2 and CO 2 . The synthesis of organic compounds by the action of electric discharges on neutral gas mixtures has been shown to be much less efficient than with reducing gas mixtures. We show here that contrary to previous findings, significant amounts of amino acids are produced under these conditions. The low yields found previously were likely the result of oxidation of the organic compounds during hydrolytic workup by nitrite and nitrate produced in the reactions. Addition of oxidation inhibitors prior to hydrolysis results in the recovery of several hundred times more amino acids than reported previously. Organic synthesis from neutral atmospheres may thus have depended as much on oceanic conditions as on the characteristics of the primitive atmosphere itself. These findings imply the need for a critical re-evaluation of the importance of such syntheses on the primitive Earth and other planetary bodies that, like Mars, may have been endowed with CO 2 and N 2 -rich atmospheres throughout most of their history.
and DEMOSS 1963) as no anthranilate synthetase could be detected in crude extracts of this mutant... more and DEMOSS 1963) as no anthranilate synthetase could be detected in crude extracts of this mutant. In addition, these same strains were tested for growth on a medium containing 20 pg/ml of anthranilic acid. None of them grew, showing that the suppressor did not restore PRA isomerase and InGP synthetase.
Physical chemistry chemical physics : PCCP, Jan 2, 2016
From a geochemical perspective, significant amounts of pure formamide (HCONH2) would have likely ... more From a geochemical perspective, significant amounts of pure formamide (HCONH2) would have likely been rare on the early Earth. There may have been mixed formamide-water solutions, but even in the presence of catalyst, solutions with >20 weight% water in formamide would not have produced significant amounts of prebiotic compounds. It might be feasible to produce relatively pure formamide by a rare occurrence of freezing formamide/water mixtures at temperatures lower than formamide's freezing point (2.55 °C) but greater than the freezing point of water. Because of the high density of formamide ice it would have sunk and accumulated at the bottom of the solution. If the remaining water froze on the surface of this ice, and was then removed by a sublimation-ablation process, a small amount of pure formamide ice might have been produced. In addition a recent report suggested that ∼85 weight% formamide could be prepared by a geochemical type of fractional distillation process, offe...
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Papers by John H Chalmers