Cellular content of biomolecules in sub-seafloor microbial communities
Cellular content of biomolecules in sub-seafloor microbial communities
复制标题
DOI：
10.1016/j.gca.2016.06.019
复制
发表时间：
2016-09-01
影响因子：
5
通讯作者：
Lomstein, Bente Aa.
中科院分区：
文献类型：
--
作者：
Braun, Stefan;Morono, Yuki;Lomstein, Bente Aa.
微生物生物分子，通常来自细胞包膜，能够提供有关海底以下微生物群落分布、活性和适应性的关键信息。然而，当细胞死亡时，这些分子可以在沉积物中保存的时间尺度可能比其微生物来源的寿命更长。在此，我们首次对沉积微生物细胞中生物分子的细胞含量进行了测量。我们通过密度离心从表层、深埋、富含有机物和贫有机物的海洋沉积物样本中，将完整细胞从沉积物基质中分离出来。对整个沉积物和细胞提取物中的氨基酸、氨基糖、胞壁酸和完整极性脂质进行了分析，并在纯度、分离效率、分类相似性以及与用于生物分子分析的高效液相色谱和质谱的兼容性方面对细胞分离进行了优化和评估。由于密度离心得到的细胞提取物中仍然含有大量碎屑颗粒和非细胞生物分子，我们通过荧光激活细胞分选（FACS）进一步纯化了两个样本中的细胞。来自这些高度纯化细胞提取物的细胞，其氨基酸和脂质的平均含量分别为每个细胞23 - 28飞克和每个细胞2.3飞克，估计碳含量为每个细胞19 - 24飞克。在沉积物中，与营养细胞相关的生物分子数量比总生物分子含量低多达70倍。我们发现海洋地下生物分子的细胞含量比之前的估计低多达4倍。我们的方法将促进并改进生物分子作为环境样本中微生物丰度指标的应用，并最终对微生物生物量提供更好的全球估计。（C）2016爱思唯尔有限公司。保留所有权利。
Microbial biomolecules, typically from the cell envelope, can provide crucial information about distribution, activity, and adaptations of sub-seafloor microbial communities. However, when cells die these molecules can be preserved in the sediment on timescales that are likely longer than the lifetime of their microbial sources. Here we provide for the first time measurements of the cellular content of biomolecules in sedimentary microbial cells. We separated intact cells from sediment matrices in samples from surficial, deeply buried, organic-rich, and organic-lean marine sediments by density centrifugation. Amino acids, amino sugars, muramic acid, and intact polar lipids were analyzed in both whole sediment and cell extract, and cell separation was optimized and evaluated in terms of purity, separation efficiency, taxonomic resemblance, and compatibility to high-performance liquid chromatography and mass spectrometry for biomolecule analyses. Because cell extracts from density centrifugation still contained considerable amounts of detrital particles and non-cellular biomolecules, we further purified cells from two samples by fluorescence-activated cell sorting (FACS). Cells from these highly purified cell extracts had an average content of amino acids and lipids of 23-28 fg cell(-1) and 2.3 fg cell(-1), respectively, with an estimated carbon content of 19-24 fg cell(-1). In the sediment, the amount of biomolecules associated with vegetative cells was up to 70-fold lower than the total biomolecule content. We find that the cellular content of biomolecules in the marine subsurface is up to four times lower than previous estimates. Our approach will facilitate and improve the use of biomolecules as proxies for microbial abundance in environmental samples and ultimately provide better global estimates of microbial biomass. (C) 2016 Elsevier Ltd. All rights reserved.