A blueprint for life forms on Mars?

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对加拿大北极地区微生物的基因组分析让美狮贵宾会首页了解到火星上可能存在的生命形式
Published: 21Jun2022
Microbes taken from surface sediment near Lost Hammer Spring, Canada, about 900 km south of the North Pole, 能否为曾经存在过的生命形式提供一个蓝图, or may still exist, on Mars. | Une分析génomique de microbes prélevés sur des sédiments de surface près de la source de Lost Hammer, à environ 900 km au sud du pôle Nord, au Canada, 所有易受影响的存在者的类型都是这样的, ou d’avoir existé, sur Mars.
Image by Elisse Magnuson.

The extremely salty, very cold, 加拿大北极高地的Lost Hammer Spring永久冻土下几乎无氧的环境与火星上的某些地区最相似. So, 如果你想了解更多关于火星上可能曾经存在或可能仍然存在的生命形式的信息, this is a good place to look. After much searching under extremely difficult conditions, 美狮贵宾会的研究人员发现了以前从未被发现的微生物. Moreover, by using state-of-the-art genomic techniques, they have gained insight into their metabolisms. In a recent paper in ISME, the scientists demonstrate, for the first time, that microbial communities found living in Canada’s High Arctic, in conditions analogous to those on Mars, 可以通过吃和呼吸一种简单的无机化合物而生存,这种化合物已经在火星上被探测到(比如甲烷, sulfide, sulfate, carbon monoxide, and carbon dioxide). 这一发现是如此引人注目,以至于欧洲航天局选择了失落之锤表面沉积物的样本,以测试他们计划在下一次ExoMars任务中使用的仪器的生命探测能力.

Developing a blueprint for life on Mars

Lost Hammer Spring, in Nunavut in Canada’s High Arctic, 这是迄今为止发现的最冷、最咸的陆地温泉之一吗. 流经600米永久冻土层到地表的水盐度极高(约24%的盐度)。, perennially at sub-zero temperatures (~−5 °C) and contains almost no oxygen (<1ppm dissolved oxygen). 极高的盐浓度使失落之锤的泉水不会结冰, 因此即使在零下的温度下也能保持液态水的栖息地. 这些条件与火星上某些地区的情况类似, 在哪里广泛的盐沉积和可能的冷盐泉被观察到. 虽然早期的研究已经在这种类似火星的环境中发现了微生物的证据,但这是为数不多的发现微生物存活和活跃的研究之一

为了深入了解火星上可能存在的生命形式, a McGill University research team, led by Lyle Whyte of the Department of Natural Resource Sciences, 是否使用了最先进的基因组工具和单细胞微生物学方法来识别和描述一个新的, and more importantly, an active microbial community in this unique spring. 找到这些微生物并对它们的DNA和mRNA进行测序并非易事.

It takes an unusual life form to survive in difficult conditions

美狮贵宾会首页花了几年时间研究沉积物,才成功地检测到活跃的微生物群落,” explains Elisse Magnuson, a PhD student in Whyte’s lab, and the first author on the paper. “环境的盐度会干扰微生物的提取和测序, 所以当美狮贵宾会首页能够找到活跃的微生物群落的证据时, it was a very satisfying experience.”

The team isolated and sequenced DNA from the spring community, 使他们能够重建大约110个微生物的基因组, most of which have never been seen before. 这些基因组使研究小组能够确定这些生物是如何在这种独特的极端环境中生存和繁荣的, 作为类似环境下潜在生命形式的蓝图. Through mRNA sequencing, 该团队能够识别基因组中的活跃基因,并基本上识别出一些在极端春季环境中活跃代谢的非常不寻常的微生物.

No need for organic material to support life

美狮贵宾会首页在失落之锤泉发现和描述的微生物令人惊讶, because, unlike other microorganisms, they don’t depend on organic material or oxygen to live,” adds Whyte. “Instead, 它们靠进食和呼吸简单的无机化合物(如甲烷)生存, sulfides, sulfate, carbon monoxide and carbon dioxide, all of which are found on Mars. 它们还可以固定大气中的二氧化碳和氮气, 所有这些都使它们高度适应在地球内外极端环境中生存和繁荣.”

研究的下一步将是培养和进一步表征这一奇怪的微生物生态系统中最丰富和最活跃的成员, 为了更好地理解它们为什么以及如何在严寒中茁壮成长, salty, muck of the Lost Hammer Spring. The researchers hope that this, in turn, 将有助于解释美国宇航局好奇号火星车最近在火星盖尔陨石坑获得的令人兴奋但神秘的硫和碳同位素.

About this study

“在缺氧环境下,活跃的岩石自养和甲烷氧化微生物群落, sub-zero, and hypersaline High Arctic spring” by Magnuson, E. Altshuler, I., Fernández-Martínez, M.Á. et al in ISME J

DOI: http://doi.org/10.1038/s41396-022-01233-8


About McGill University

Founded in Montreal, Quebec, in 1821, 美狮贵宾会是加拿大排名第一的医学博士大学. 美狮贵宾会一直被评为全国和国际顶尖大学之一. 它是一所世界知名的高等学府,研究活动横跨三个校区, 11 faculties, 13 professional schools, 300 programs of study and over 39,000 students, including more than 10,400 graduate students. McGill attracts students from over 150 countries around the world, its 12,000 international students making up 30% of the student body. 美狮贵宾会超过一半的学生声称自己的第一语言不是英语, 其中大约20%的学生说法语是他们的母语.

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