Aspartic acid racemization and age-depth relationships for organic carbon in Siberian permafrost
Aspartic acid racemization and age-depth relationships for organic carbon in Siberian permafrost
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DOI：
10.1089/153110702753621358
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发表时间：
2002-03-01
期刊：
影响因子：
4.2
通讯作者：
McDonald, GD
中科院分区：
文献类型：
--
作者：
Brinton, KLF;Tsapin, AI;McDonald, GD
我们已经分析了从北方西伯利亚，从该地区的微生物的表观年龄高达几百万年以前已被分离和培养的永久冻土样品中的天冬氨酸的外消旋化的程度。我们发现，多年冻土核心的天冬氨酸消旋化程度增加非常缓慢，直到年龄接近25,000年（约5米深）。用测定的天冬氨酸消旋化速率常数确定的0- 25，000年年龄范围内消旋化的表观温度为-19 ℃。这一明显的消旋温度明显低于测量的环境温度（-11至-13摄氏度），并表明西伯利亚永久冻土中D-天冬氨酸的活跃再循环长达25，000年左右。这表明，冻土生物能够修复一些分子损伤，而在地质时期的“休眠”状态。
We have analyzed the degree of racemization of aspartic acid in permafrost samples from Northern Siberia, an area from which microorganisms of apparent ages up to a few million years have previously been isolated and cultured. We find that the extent of aspartic acid racemization in permafrost cores increases very slowly up to an age of similar to25,000 years (around 5 m in depth). The apparent temperature of racernization over the age range of 0-25,000 years, determined using measured aspartic acid racernization rate constants, is -19degreesC. This apparent racernization temperature, is significantly lower than the measured environmental temperature (-11 to -13degreesC) and suggests active recycling Of D-aspartic acid in Siberian permafrost up to, an age of around 25,000 years. This indicates that permafrost organisms are capable of repairing some molecular damage incurred while in a "dormant" state over geologic time.