LEXEN: Biogenic Fractionations of Transition Metal Isotopes: Novel Methods for the Examination of Life in Extreme Environments

罗切斯特大学地球和环境科学系的Ariel D.Anbar教授和Kenneth H.Nealson教授得到了化学系、数学和物理科学局多学科活动办公室、生物科学局和地球科学司的支助，他们研究过渡金属同位素的生物成因分馏。这些研究检验了这样一种假设，即关键代谢金属的稳定同位素在微生物吸收和代谢这些金属的过程中发生分馏，这种同位素分馏将留下一个可识别的特征，这将有助于在极端条件下阻止其他生物标志物应用的环境中的生命研究。Anbar和Nealson教授使用多收集器电感耦合等离子体质谱来表征从野外采样的微生物和在受控实验室条件下培养的微生物中分离出来的金属的同位素组成。他们的研究重点是铜和锌的同位素在酶催化吸收过程中的动力学分馏，以及铁的动力学分馏，预计在微生物介导的氧化还原反应中。这些生物来源的同位素分馏预计将提供有关一般生物活动的存在或不存在的信息，特别是关于特定代谢过程的信息。碳、氮和硫的稳定同位素的分馏是由于含有这些元素的不同同位素的化合物的反应速度不同而引起的，多年来一直被用来获得有关环境中无法直接观察到的代谢过程的信息。在化学司、数学和物理科学局多学科活动办公室、生物科学局和地球科学司的支持下，罗切斯特大学地球和环境科学系的Ariel D.Anbar教授和Kenneth H.Nealson教授正在开发技术，以探索在代谢过程中发挥关键作用的金属同位素的生物成因分馏。通过分析铜、锌和铁的同位素分馏，Anbar教授和Nealson教授获得了关于生物活动的一般存在或不存在的信息，特别是关于特定的代谢过程的信息。这些研究对于研究极端环境中的生命特别有用，因为极端环境条件排除了其他生物标志物的应用。这类环境包括物理上偏远或受极端环境条件影响的现代环境，以及只能通过地质记录才能研究的古代环境。

Professors Ariel D. Anbar and Kenneth H. Nealson, of the Department of Earth and Environmental Sciences at the University of Rochester, are supported by the Division of Chemistry, the Office of Multidisciplinary Activities of the Mathematical and Physical Sciences Directorate, the Directorate for Biological Sciences, and the Division of Earth Sciences for their studies of the biogenic fractionation of transition metal isotopes. These studies test the hypothesis that fractionation of stable isotopes of key metabolic metals occurs during uptake and metabolism of these metals by microorganisms and that such isotope fractionation will leave a recognizable signature that will be useful for the study of life in environments where extreme conditions preclude the application of other biomarkers. Professors Anbar and Nealson use multiple-collector inductively-coupled plasma mass spectrometry to characterize the isotopic compositions of metals isolated from microorganisms sampled in the field and from microbes cultured under controlled laboratory conditions. Their studies are focused on the kinetic fractionation of the isotopes of copper and zinc, expected during the enzyme-catalyzed uptake of these metals, and of iron, expected during microbially-mediated redox reactions. These biogenic isotope fractionations are expected to provide information about the presence or absence of biological activity in general and about specific metabolic processes in particular. Fractionation of stable isotopes of carbon, nitrogen, and sulfur due to the different reaction rates of compounds containing different isotopes of these elements have been used for years to obtain information about metabolic processes in environments not accessible to direct observation. With the support of the Division of Chemistry, the Office of Multidisciplinary Activities of the Mathematical and Physical Sciences Directorate, the Directorate for Biological Sciences, and the Division of Earth Sciences, Professors Ariel D. Anbar and Kenneth H. Nealson, of the Department of Earth and Environmental Sciences at the University of Rochester, are developing techniques to explore the biogenic fractionation of isotopes of metals which play key roles in metabolic processes. By analyzing the fractionation of isotopes of copper, zinc, and iron, Professors Anbar and Nealson obtain information about the presence or absence of biological activity in general and about specific metabolic processes in particular. These studies are of particular utility for the study of life in extreme environments, where extreme conditions preclude the application of other `biomarkers.` Such environments include modern settings which are physically remote or subject to extreme environmental conditions and ancient environments which can be studied only through the geological record.