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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Temperature dependence of metabolic rates for microbial growth, maintenance, and survival
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Temperature dependence of metabolic rates for microbial growth, maintenance, and survival

机译：代谢速率对微生物生长，维持和存活的温度依赖性

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Our work was motivated by discoveries of prokaryotic communities that survive with little nutrient in ice and permafrost with implications for past or present microbial life in Martian permafrost and Europan ice. We compared the temperature dependence of metabolic rates of microbial communities in permafrost, ice, snow, clouds, oceans, lakes, marine and freshwater sediments, and subsurface aquifer sediments. Metabolic rates per cell fall into three groupings: (i) a rate, mu(g)(T), for growth, measured in the laboratory at in situ temperatures with minimal disturbance of the medium; (ii) a rate, mu(m)(T), sufficient for maintenance of functions but for a nutrient level too low for growth; and (iii) a rate, mu(s)(T), for survival of communities imprisoned in deep glacial ice, subsurface sediment or ocean sediment, in which they can repair macromolecular damage but are probably largely dormant. The three groups have metabolic rates consistent with a single activation energy of approximate to110 U and that scale as mu(g)(T):mu(m)(T):mu(s)(T) approximate to 10(6):10(3):1. There is no evidence of a minimum temperature for metabolism. The rate at -40degreesC in ice corresponds to approximate to10 turnovers of cellular carbon per billion years. Microbes in ice and permafrost have metabolic rates similar to those in water, soil, and sediment at the same temperature. This finding supports the view that, far below the freezing point, liquid water inside ice and permafrost is available for metabolism. The rate mu(s)(T) for repairing molecular damage by means of DNA-repair enzymes and protein-repair enzymes such as methyltransferase is found to be comparable to the rate of spontaneous molecular damage. [References: 64]
机译：我们的工作是受原核生物群落的发现激励的，这些原核生物在冰和多年冻土中几乎没有营养就能够生存，这对火星多年冻土和欧罗攀冰中的过去或现在的微生物生活产生了影响。我们比较了多年冻土，冰，雪，云，海洋，湖泊，海洋和淡水沉积物以及地下含水层沉积物中微生物群落代谢速率对温度的依赖性。每个细胞的代谢速率可分为三类：（i）在实验室中在原位温度下对培养基的干扰最小的生长速率mu（g）（T）； （ii）足以维持功能但营养水平过低而无法维持生长的速度μ（m）（T​​）； （iii）囚禁在深冰冰川，地下沉积物或海洋沉积物中的社区的生存率，其可以修复大分子破坏但可能大部分处于休眠状态。这三组的代谢率与单次激活能量约110 U一致，并且随着mu（g）（T）：mu（m）（T​​）：mu（s）（T）的变化而变化，近似为10（6）： 10（3）：1。没有证据表明新陈代谢的最低温度。在-40°C的冰中速率大约相当于每十亿年10个细胞碳的周转量。在相同温度下，冰和永冻土中的微生物的代谢速率与水，土壤和沉积物中的微生物相似。这一发现支持了这样一种观点，即远低于冰点的冰和永久冻土内部的液态水可用于新陈代谢。发现通过DNA修复酶和蛋白质修复酶如甲基转移酶修复分子损伤的速率μ（T）与自发分子损伤的速率相当。 [参考：64]

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