Abiotic Condensation Synthesis of Glyceride Lipids and Wax Esters Under Simulated Hydrothermal Conditions

Abstract

Precursor compounds for abiotic proto cellular membranes are necessary for the origin of life. Amphipathic compounds such as fatty acids and acyl glycerols are important candidates for micelle/bilayer/vesicle formation. Two sets of experiments were conducted to study dehydration reactions of model lipid precursors in aqueous media to form acyl polyols and wax esters, and to evaluate the stability and reactions of the products at elevated temperatures. In the first set, mixtures of n-nonadecanoic acid and ethylene glycol in water, with and without oxalic acid, were heated at discrete temperatures from 150 ( composite function)C to 300 ( composite function)C for 72 h. The products were typically alkyl alkanoates, ethylene glycolyl alkanoates, ethylene glycolyl bis-alkanoates and alkanols. The condensation products had maximum yields between 150 ( composite function)C and 250 ( composite function)C, and were detectable and thus stable under hydrothermal conditions to temperatures < 300 ( composite function)C. In the second set of experiments, mixtures of n-heptanoic acid and glycerol were heated using the same experimental conditions, with and without oxalic acid, between 100 ( composite function)C and 250 ( composite function)C. The main condensation products were two isomers each of monoacylglycerols and diacylglycerols at all temperatures, as well as minor amounts of the fatty acid anhydride and methyl ester. The yield of glyceryl monoheptanoates generally increased with increasing temperature and glyceryl diheptanoates decreased noticeably with increasing temperature. The results indicate that condensation reactions and abiotic synthesis of organic lipid compounds under hydrothermal conditions occur easily, provided precursor concentrations are sufficiently high.

Simulation of triacylglycerol ion profiles: bioinformatics for interpretation of triacylglycerol biosynthesis

“…It is clear that this bioinformatic tool in combination with lipidomics analysis could allow us to reveal potential biochemical mechanisms underpinning TAG accumulation under different pathophysiological conditions, which is of particular signifi cance at a time when obesity and lipotoxicity are becoming epidemic. with lipase activities ( 26 ), in addition to possible direct acylation of glycerol ( 27 ).…”

“…1 ). These pathways include the DAG pools resulting from i ) the dephosphorylation of phosphatidic acid (PA) (DAG PA ); ii ) the reacylation of monoacylglycerol (MAG) species (DAG MAG ), which could result from multiple sources including dephosphorylation of lysophosphatidic acid, TAG/DAG hydrolysis with lipase activities, and reacylation from glycerol ( 26,27 ); and iii ) to a minimal extent, the hydrolysis of phosphatidylinositol (PI) species through phospholipase C (PLC) activities (DAG PI ). It should be pointed out that phosphatidylinositol-4,5-diphosphate [PI(4,5)P 2 ] species are the known substrates of PLC with a high turnover rate.…”

Synthesis of guanidine from ammonium thiocyanate in solid state

“…Several advantages can be cited to use simulated submarine hydrothermal vent conditions as prebiotic environment: the biomolecules and biopolymers were protected from UV rays of the sun, the gradient of temperature provides energy and different sites for different reactions, at high temperature and high pressure the water behavior like an organic solvent and salts of seawater, transition metals and clays of hydrothermal vents catalyze the syntheses of biomolecules and biopolymers. 14,15 Under hydrothermal conditions, the syntheses of biomolecules, [15][16][17] biopolymers 15,[18][19][20][21][22] and microspheres, 15,22 was obtained. The prebiotic environments that could be corresponding of laboratory experiments of reaction of substances in solid state are: cooling lava from volcanoes on the ground and impact of bolides (meteor, comet) on the earth.…”

Adsorção de aminoácidos sobre minerais e a origem da vida

“…Estas substâncias provavelmente foram muito comuns na Terra primitiva e diversas vantagens podem ser citadas em favor do mundo dos lipídios: estas moléculas se agrupam espontaneamente em complexas estruturas supramoleculares; estas estruturas supramoleculares podem agir como catalisadores e, contêm informação devido sua composição, podendo evoluir [54][55][56][57][58][59][60][61] . A polimerização de glicina dentro de vesículas de lipídios em hidrotermais foi estudada por Tsukahara et al 62 .…”