Limited influence of Si on the preservation of Fe mineral‐encrusted microbial cells during experimental diagenesis
Limited influence of Si on the preservation of Fe mineral‐encrusted microbial cells during experimental diagenesis
复制标题
硅对实验成岩过程中铁矿物包裹微生物细胞的保存影响有限
作者：
Picard;M. Schmid;Zeitvogel;Kappler
由于难以证明岩石记录中假定的微体化石的生物起源性，重建微生物生命在早期地球上出现以来的历史受到了损害。虽然地球上大多数最古老的岩石都暴露在不同等级的成岩蚀变中，但人们对微生物遗骸在暴露于成岩作用的典型压力（P）和温度（T）条件下如何演变知之甚少。使用光谱学和显微镜，我们比较了形态学，矿物学和化学生物特征所表现出的铁矿物结壳细胞的细菌Acidovoraxsp。在环境条件下和实验成岩作用后长期孵育后的BoFeN 1。我们还评估了在整个过程中Si对微生物细胞保存的影响。在环境条件下，硅的形态，但不影响的身份（针铁矿）的铁矿物周围形成的细胞。在存在或不存在Si的情况下，在250 °C-140 MPa下1周后和在170 °C-120 MPa下16周后，铁结壳细胞在形态上保存良好。一些针铁矿在250 °C-140 MPa下转化为赤铁矿和磁铁矿，但在Si的存在下，更多的针铁矿被保留下来。蛋白质-最丰富的细胞成分-被保存在几个月内在环境条件下，但在高温和高压条件下孵育后消失，无论是在存在和不存在的Si。其他有机化合物，如脂类和胞外多糖，在暴露于成岩条件后似乎保存良好。这项研究提供了有关可能在富含Fe和Si的前寒武纪海洋中形成的微体化石的组成和潜在保存的见解。
The reconstruction of the history of microbial life since its emergence on early Earth is impaired by the difficulty to prove the biogenicity of putative microfossils in the rock record. While most of the oldest rocks on Earth have been exposed to different grades of diagenetic alterations, little is known about how the remains of micro‐organisms evolve when exposed to pressure (P) and temperature (T) conditions typical of diagenesis. Using spectroscopy and microscopy, we compared morphological, mineralogical, and chemical biosignatures exhibited by Fe mineral‐encrusted cells of the bacteriumAcidovoraxsp. BoFeN1 after long‐term incubation under ambient conditions and after experimental diagenesis. We also evaluated the effects of Si on the preservation of microbial cells during the whole process. At ambient conditions, Si affected the morphology but not the identity (goethite) of Fe minerals that formed around cells. Fe‐encrusted cells were morphologically well preserved after 1 week at 250 °C‐140 MPa and after 16 weeks at 170 °C‐120 MPa in the presence or in the absence of Si. Some goethite transformed to hematite and magnetite at 250 °C‐140 MPa, but in the presence of Si more goethite was preserved. Proteins—the most abundant cellular components—were preserved over several months at ambient conditions but disappeared after incubations at high temperature and pressure conditions, both in the presence and in the absence of Si. Other organic compounds, such as lipids and extracellular polysaccharides seemed well preserved after exposure to diagenetic conditions. This study provides insights about the composition and potential preservation of microfossils that could have formed in Fe‐ and Si‐rich Precambrian oceans.
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模拟二氧化硅烧结体中细长聚球藻细胞模具的形成和保存：对微化石鉴定的意义
DOI：
--
发表时间：
2013
期刊：
影响因子：
--
作者：
F. Orange;S. Lalonde;K. Konhauser
通讯作者：
K. Konhauser
DOI：
10.1073/pnas.1419563112
发表时间：
2015-05-12
影响因子：
11.1
作者：
French, Katherine L.;Hallmann, Christian;Summons, Roger E.
通讯作者：
Summons, Roger E.
影响因子：
3.7
作者：
Gregor Schmid;Fabian Zeitvogel;Likai Hao;Pablo Ingino;Matthias Floetenmeyer;Y. Stierhof;Birgit Schroeppel
通讯作者：
Gregor Schmid;Fabian Zeitvogel;Likai Hao;Pablo Ingino;Matthias Floetenmeyer;Y. Stierhof;Birgit Schroeppel
影响因子：
11.4
作者：
Dippon, Urs;Pantke, Claudia;Kappler, Andreas
通讯作者：
Kappler, Andreas
影响因子：
4.4
作者：
Klueglein, Nicole;Zeitvogel, Fabian;Obst, Martin
通讯作者：
Obst, Martin