Microbial life in glacial ice and implications for a cold origin of life
Microbial life in glacial ice and implications for a cold origin of life
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DOI：
10.1111/j.1574-6941.2006.00234.x
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发表时间：
2007-02-01
影响因子：
4.2
通讯作者：
Buford Price, P.
中科院分区：
文献类型：
--
作者：
Buford Price, P.
物理和化学概念的应用，加上对冰芯和永久冻土中的原核生物的研究，已经使人们了解微生物如何在地球上以及可能在火星和其他寒冷的行星体上在冰点以下的温度下进行代谢。低温下的生命栖息地得益于冰的两个不同寻常的特性。首先，几乎所有的离子杂质都不溶于冰的晶体结构中，这导致了微米直径的静脉网络，微生物可以在其中利用离子进行代谢。其次，与矿物表面接触的冰会形成一层纳米厚的未冻水膜，这为微生物提供了第二个栖息地，可以让微生物从与水膜中的离子或矿物结构中的离子的氧化还原反应中提取能量。在早期的地球和冰冷的行星上，冰脉中的生命元分子可能会聚合成RNA和多肽，这是因为冰脉中的水活度低，彼此在近一维轨迹上的相遇率高。益生元分子也可以利用谷物表面来增加相遇率和利用表面的其他物理化学特征。
Application of physical and chemical concepts, complemented by studies of prokaryotes in ice cores and permafrost, has led to the present understanding of how microorganisms can metabolize at subfreezing temperatures on Earth and possibly on Mars and other cold planetary bodies. The habitats for life at subfreezing temperatures benefit from two unusual properties of ice. First, almost all ionic impurities are insoluble in the crystal structure of ice, which leads to a network of micron-diameter veins in which microorganisms may utilize ions for metabolism. Second, ice in contact with mineral surfaces develops a nanometre-thick film of unfrozen water that provides a second habitat that may allow microorganisms to extract energy from redox reactions with ions in the water film or ions in the mineral structure. On the early Earth and on icy planets, prebiotic molecules in veins in ice may have polymerized to RNA and polypeptides by virtue of the low water activity and high rate of encounter with each other in nearly one-dimensional trajectories in the veins. Prebiotic molecules may also have utilized grain surfaces to increase the rate of encounter and to exploit other physicochemical features of the surfaces.