Intramolecular stable carbon isotopic analysis of archaeal glycosyl tetraether lipids.
Intramolecular stable carbon isotopic analysis of archaeal glycosyl tetraether lipids.
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古菌糖基四醚脂质的分子内稳定碳同位素分析。
DOI：
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发表时间：
2010
影响因子：
2
通讯作者：
K. Hinrichs
中科院分区：
文献类型：
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作者：
Yu‐Shih Lin;J. Lipp;M. Yoshinaga;Shao;M. Elvert;K. Hinrichs
糖脂是生命各个领域细胞膜的重要成分。例如，二糖基甘油二联植烷基甘油四醚（2Gly-GDGT）与甲烷氧化ANME-1古细菌和异养底栖古细菌有关，这两个古细菌群具有全球生物地球化学重要性。来自这两个未培养的古菌群的 2Gly-GDGT 的疏水性联植烷部分表现出不同的碳同位素组成。为了探索糖头基的同位素组成是否提供有关其生产者代谢的额外信息，我们开发了一种分析糖苷头基的 δ(13)C 值的程序。通过以下方式成功确定：(1) 监测脂质提取和制备过程中游离糖的污染，(2) 优化糖脂的水解条件，以及 (3) 将所得糖衍生成醛糖腈乙酸酯衍生物，该衍生物足够稳定，可以承受后续的柱纯化步骤。获得了两个海洋沉积物样品中 2Gly-GDGT 裂解糖的 δ(13)C 值的第一个结果，其中一个主要含有 ANME-1 古菌，另一个含有底栖古菌，并与相应联植烷的 δ(13)C 值进行了比较。在两个样品中，相对于相应的主要联植烷，主要糖头基在 (13)C 中富集。 ANME-1 古菌 (~15‰) 的假定主要糖脂中的 (13)C 富集明显高于底栖古菌 (<7‰) 的糖脂。该方法为检查未培养生物体中糖和脂质之间的碳同位素关系打开了一个新的分析窗口。
Glycolipids are prominent constituents in the membranes of cells from all domains of life. For example, diglycosyl-glycerol dibiphytanyl glycerol tetraethers (2Gly-GDGTs) are associated with methanotrophic ANME-1 archaea and heterotrophic benthic archaea, two archaeal groups of global biogeochemical importance. The hydrophobic biphytane moieties of 2Gly-GDGTs from these two uncultivated archaeal groups exhibit distinct carbon isotopic compositions. To explore whether the isotopic compositions of the sugar headgroups provide additional information on the metabolism of their producers, we developed a procedure to analyze the δ(13)C values of glycosidic headgroups. Successful determination was achieved by (1) monitoring the contamination from free sugars during lipid extraction and preparation, (2) optimizing the hydrolytic conditions for glycolipids, and (3) derivatizing the resulting sugars into aldononitrile acetate derivatives, which are stable enough to withstand a subsequent column purification step. First results of δ(13)C values of sugars cleaved from 2Gly-GDGTs in two marine sediment samples, one containing predominantly ANME-1 archaea and the other benthic archaea, were obtained and compared with the δ(13)C values of the corresponding biphytanes. In both samples the dominant sugar headgroups were enriched in (13)C relative to the corresponding major biphytane. This (13)C enrichment was significantly larger in the putative major glycolipids from ANME-1 archaea (∼15‰) than in those from benthic archaea (<7‰). This method opens a new analytical window for the examination of carbon isotopic relationships between sugars and lipids in uncultivated organisms.