Abstract Bacterial mono- and dialkyl glycerol ether lipids (MAGEs and DAGEs) are potential powerful lipid biomarkers whose respective diagenetic fate still needs to be precisely assessed. To do so, the lipid content of cultures of an anaerobic bacterium synthesizing both MAGEs and DAGEs was analyzed at different growth stages and after long-term incubation under aerobic or anaerobic conditions. The proportions of the different lipid classes (fatty acids, MAGEs and DAGEs), as well as their structural distributions, did not significantly vary during anaerobic growth under optimal conditions until the stationary phase. Long-term exposure to oxygen (up to 480 days) induced the preferential degradation of fatty acids and MAGEs relative to DAGEs and of sn-1 relative to sn-2 positional isomers of MAGEs. The degradation of fatty acids and MAGEs appeared slower under anaerobic conditions and no specific structures appeared preferentially degraded. All DAGE structures were very well preserved whatever the redox conditions and the time of incubation considered (480 days and 13 years under oxic and anoxic conditions, respectively). The results highlight the excellent diagenetic stability of DAGEs and the much lower potential of preservation of MAGEs, warranting caution for an eventual use of the latter compounds as tracers of environmental or microbial community changes.

中文翻译：

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长期有氧和缺氧培养期间细菌烷基甘油醚脂质结构的选择性保存

摘要细菌单和二烷基甘油醚脂质（MAGEs 和 DAGEs）是潜在的强大脂质生物标志物，其各自的成岩作用仍需要精确评估。为此，在不同生长阶段和在有氧或厌氧条件下长期孵育后，分析了合成 MAGE 和 DAGE 的厌氧细菌培养物的脂质含量。不同脂质类别（脂肪酸、MAGE 和 DAGE）的比例及其结构分布在最佳条件下的厌氧生长过程中直到稳定期没有显着变化。长期暴露于氧气（最多 480 天）会导致脂肪酸和 MAGE 相对于 DAGE 以及 sn-1 相对于 MAGE 的 sn-2 位置异构体的优先降解。在厌氧条件下，脂肪酸和 MAGEs 的降解显得较慢，并且没有出现优先降解的特定结构。无论氧化还原条件和孵育时间如何（在有氧和缺氧条件下分别为 480 天和 13 年），所有 DAGE 结构都得到了很好的保存。结果突出了 DAGE 出色的成岩稳定性和 MAGE 保存的潜力要低得多，这需要谨慎使用后一种化合物作为环境或微生物群落变化的示踪剂。