Effects of gamma-rays and ammonia on prebiotic formation of sugars in the meteorite patent bodies

Abstract

As a prebiotic sugar formation reaction, the “formose reaction” has been attracted attention. It is considered that meteorite parent body is one of the places where the formose-type reaction occurred. Heat and/or gamma-rays could affect the reaction during aqueous alteration in there. In addition, it is known that nitrogen-containing compounds react with aldehyde, which would inhibit the formation of sugars. In this study, we evaluated comparison of sugar production by heat and gamma-rays, and effects of ammonia on formation of sugars in the meteorite parent bodies. In order to simulate reactions in the meteorite parent bodies, 2 kinds of starting mixtures were prepared: (i) formaldehyde : NH₃ : H₂O (FAW), (ii) formaldehyde : glycolaldehyde : NH₃ : H₂O (FGAW). Each mixture was heated or irradiated with gamma-rays. An aliquot of each product was derivatized, and analyzed by GC/MS. In FAW, gamma-rays irradiated samples tended to produce a wider variety and more quantity of sugars than heated samples, while almost the same amounts of sugars were produced in FGAW. In addition, more sugars were produced in the WITH-ammonia samples than the WITHOUT-ammonia samples.