美国宇航局在陨石上发现“外星糖”

美国宇航局在陨石上发现“外星糖”

It’s common for asteroids in the Solar System to carry water, one of the essential building blocks for life. But now, NASA researchers have found sugar molecules on two different meteorites, adding credence to the idea that asteroids play a crucial role in supporting life.

太阳系中的小行星携带水是很常见的，水是生命的基本组成部分之一。但是现在，美国国家航空航天局的研究人员在两颗不同的陨石上发现了糖分子，这进一步证实了小行星在维持生命方面起着至关重要的作用。

The researchers said they discovered ribose and “other bio-essential sugars including arabinose and xylose,” adding that ribose is crucial for RNA (ribonucleic acid), which copies genetic codes from DNA and delivers them to ribosomes used to build proteins essential for life.

研究人员表示，他们发现了核糖和“其他生物必需糖，包括阿拉伯糖和木糖”，并补充说，核糖对RNA(核糖核酸)至关重要，后者从DNA中复制遗传密码，并将其传递给核糖体，核糖体被用来制造生命必需的蛋白质。

“Other important building blocks of life have been found in meteorites previously, including amino acids (components of proteins) and nucleobases (components of DNA and RNA), but sugars have been a missing piece among the major building blocks of life,” said the study’s lead author, Yoshihiro Furukawa, in a statement.

该研究的第一作者古川吉弘在一份声明中说:“以前在陨石中发现过其他重要的生命构成元素，包括氨基酸(蛋白质的组成成分)和碱基(DNA和RNA的组成成分)，但糖一直是生命主要构成元素中缺失的一块。”

“The research provides the first direct evidence of ribose in space and the delivery of the sugar to Earth,” Furukawa added. “The extraterrestrial sugar might have contributed to the formation of RNA on the prebiotic Earth which possibly led to the origin of life.”

古川补充说:“这项研究提供了第一个直接证据，证明核糖存在于太空中，并将其输送到地球。”“外星的糖可能促成了生命起源前地球上RNA的形成。”

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“It is remarkable that a molecule as fragile as ribose could be detected in such ancient material,” Jason Dworkin, one of the study’s co-authors, pointed out. “These results will help guide our analyses of pristine samples from primitive asteroids Ryugu and Bennu, to be returned by the Japan Aerospace Exploration Agency’s Hayabusa2 and NASA’s OSIRIS-REx spacecraft.”

“在如此古老的物质中能够检测到像核糖这样脆弱的分子，这是值得注意的，”该研究的合著者之一贾森·德沃金(Jason Dworkin)指出。“这些结果将有助于指导我们对原始小行星龙谷星和本奴星的原始样本的分析，这些样本将由日本宇宙航空研究机构的隼鸟2号和美国宇航局的奥西里斯-雷克斯宇宙飞船返回。”

The Hayabusa2 spacecraft, which is on its way back to Earth, fired a “bullet” into the asteroid Ryugu in February to collect material from the space rock. OSIRIS-REx, which is orbiting the asteroid Bennu, has made several incredible discoveries on the space rock, including the presence of water.

今年2月，正在返回地球途中的“隼鸟二号”宇宙飞船向小行星“龙宫”发射了一颗“子弹”，以收集太空岩石中的物质。围绕小行星Bennu运行的奥西里斯-雷克斯在这块太空岩石上有了一些令人难以置信的发现，其中包括水的存在。

Although the sugar in DNA was not detected in any of the meteorites, the researchers noted the presence of the “extraterrestrial sugar” that makes up RNA is important, nonetheless, with many researchers thinking it came first, only to be replaced by DNA.

虽然没有在任何陨石中检测到DNA中的糖，但研究人员指出，构成RNA的“外星糖”的存在很重要，尽管如此，许多研究人员认为它是最先出现的，只是被DNA取代了。

“The sugar in DNA (2-deoxyribose) was not detected in any of the meteorites analyzed in this study,” said Danny Glavin, a co-author of the study, added. “This is important since there could have been a delivery bias of extraterrestrial ribose to the early Earth which is consistent with the hypothesis that RNA evolved first.”

“在这项研究分析的所有陨石中都没有检测到DNA中的糖(2-脱氧核糖)，”该研究的合著者丹尼·格莱文(Danny Glavin)补充说。“这很重要，因为可能有一种来自外星的核糖传送到早期地球的倾向，这与RNA首先进化的假设是一致的。”

Researchers ruled out the possibility of terrestrial sugars when they analyzed it, noting that the carbon in the sugars from the meteorites were “significantly enriched in the heavy 13C, beyond the amount seen in terrestrial biology.”

研究人员在分析时排除了地球上存在糖的可能性，他们指出，陨石中碳的含量“在重13C中显著增加，超过了地球生物的含量”。

The research has been published in the scientific journal Proceedings of the National Academy of Sciences.

这项研究发表在《美国国家科学院院刊》上。