Université Paris-Sud , "Astrochimie et Origines," Institut d'Astrophysique Spatiale, Orsay, France.
Astrobiology. 2011 Nov;11(9):847-54. doi: 10.1089/ast.2011.0677. Epub 2011 Nov 7.
The delivery of extraterrestrial organic materials to primitive Earth from meteorites or micrometeorites has long been postulated to be one of the origins of the prebiotic molecules involved in the subsequent apparition of life. Here, we report on experiments in which vacuum UV photo-irradiation of interstellar/circumstellar ice analogues containing H(2)O, CH(3)OH, and NH(3) led to the production of several molecules of prebiotic interest. These were recovered at room temperature in the semi-refractory, water-soluble residues after evaporation of the ice. In particular, we detected small quantities of hydantoin (2,4-imidazolidinedione), a species suspected to play an important role in the formation of poly- and oligopeptides. In addition, hydantoin is known to form under extraterrestrial, abiotic conditions, since it has been detected, along with various other derivatives, in the soluble part of organic matter of primitive carbonaceous meteorites. This result, together with other related experiments reported recently, points to the potential importance of the photochemistry of interstellar "dirty" ices in the formation of organics in Solar System materials. Such molecules could then have been delivered to the surface of primitive Earth, as well as other telluric (exo-) planets, to help trigger first prebiotic reactions with the capacity to lead to some form of primitive biomolecular activity.
从陨石或微陨石向原始地球输送外星有机物质，长期以来一直被认为是参与随后生命出现的前生物分子的起源之一。在这里，我们报告了实验结果，即在含有 H(2)O、CH(3)OH 和 NH(3) 的星际/星周冰类似物的真空紫外光辐照下，导致了几种具有前生物兴趣的分子的产生。这些分子在冰蒸发后，在半 refractory、水溶性残留物中，于室温下回收。特别是，我们检测到少量的海因（2,4-咪唑烷二酮），这种物质被怀疑在聚肽和寡肽的形成中起重要作用。此外，由于在原始碳质陨石的有机物可溶性部分中检测到海因及其它各种衍生物，因此在地球外无生命条件下，海因也会形成。这一结果与最近报道的其他相关实验一起，表明星际“肮脏”冰的光化学在太阳系物质中形成有机物的潜在重要性。这些分子随后可能被输送到原始地球表面以及其它类地（系外）行星，以帮助引发最初具有前生物活性的反应。
