美國(guó)宇航局在隕石上發(fā)現(xiàn)“外星糖”

美國(guó)宇航局在隕石上發(fā)現(xiàn)“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.

太陽(yáng)系中的小行星攜帶水是很常見(jiàn)的，水是生命的基本組成部分之一。但是現(xiàn)在，美國(guó)國(guó)家航空航天局的研究人員在兩顆不同的隕石上發(fā)現(xiàn)了糖分子，這進(jìn)一步證實(shí)了小行星在維持生命方面起著至關(guān)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.

研究人員表示，他們發(fā)現(xiàn)了核糖和“其他生物必需糖，包括阿拉伯糖和木糖”，并補(bǔ)充說(shuō)，核糖對(duì)RNA(核糖核酸)至關(guān)重要，后者從DNA中復(fù)制遺傳密碼，并將其傳遞給核糖體，核糖體被用來(lái)制造生命必需的蛋白質(zhì)。

“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.

該研究的第一作者古川吉弘在一份聲明中說(shuō):“以前在隕石中發(fā)現(xiàn)過(guò)其他重要的生命構(gòu)成元素，包括氨基酸(蛋白質(zhì)的組成成分)和堿基(DNA和RNA的組成成分)，但糖一直是生命主要構(gòu)成元素中缺失的一塊。”

“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.”

古川補(bǔ)充說(shuō):“這項(xiàng)研究提供了第一個(gè)直接證據(jù)，證明核糖存在于太空中，并將其輸送到地球。”“外星的糖可能促成了生命起源前地球上RNA的形成。”

iStockphoto

“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.”

“在如此古老的物質(zhì)中能夠檢測(cè)到像核糖這樣脆弱的分子，這是值得注意的，”該研究的合著者之一賈森·德沃金(Jason Dworkin)指出。“這些結(jié)果將有助于指導(dǎo)我們對(duì)原始小行星龍谷星和本奴星的原始樣本的分析，這些樣本將由日本宇宙航空研究機(jī)構(gòu)的隼鳥(niǎo)2號(hào)和美國(guó)宇航局的奧西里斯-雷克斯宇宙飛船返回。”

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“隼鳥(niǎo)二號(hào)”宇宙飛船向小行星“龍宮”發(fā)射了一顆“子彈”，以收集太空巖石中的物質(zhì)。圍繞小行星Bennu運(yùn)行的奧西里斯-雷克斯在這塊太空巖石上有了一些令人難以置信的發(fā)現(xiàn)，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.

雖然沒(méi)有在任何隕石中檢測(cè)到DNA中的糖，但研究人員指出，構(gòu)成RNA的“外星糖”的存在很重要，盡管如此，許多研究人員認(rèn)為它是最先出現(xiàn)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.”

“在這項(xiàng)研究分析的所有隕石中都沒(méi)有檢測(cè)到DNA中的糖(2-脫氧核糖)，”該研究的合著者丹尼·格萊文(Danny Glavin)補(bǔ)充說(shuō)。“這很重要，因?yàn)榭赡苡幸环N來(lái)自外星的核糖傳送到早期地球的傾向，這與RNA首先進(jìn)化的假設(shè)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.”

研究人員在分析時(shí)排除了地球上存在糖的可能性，他們指出，隕石中碳的含量“在重13C中顯著增加，超過(guò)了地球生物的含量”。

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

這項(xiàng)研究發(fā)表在《美國(guó)國(guó)家科學(xué)院院刊》上。