Anaerobic metabolism of Foraminifera thriving below the seafloor
Anaerobic metabolism of Foraminifera thriving below the seafloor
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有孔虫的无氧代谢在海底蓬勃发展
DOI：
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
M. Kučera
中科院分区：
文献类型：
--
作者：
W. Orsi;R. Morard;A. Vuillemin;M. Eitel;G. Wörheide;J. Milucka;M. Kučera
有孔虫是具有重要生态意义的单细胞真核生物（原生生物），也是环境和古环境指标和生物地层学工具。此外，它们能够在缺氧海洋环境中生存，是海底生物群落的主要组成部分。然而，有孔虫对缺氧环境的细胞适应仍然受到很大的限制。我们采样的海洋沉积物中的缺氧-缺氧过渡区从纳米比亚大陆架，其中属Boliocarbia和Aprilforthia占主导地位的有孔虫群落，并使用元转录组学来表征有孔虫代谢在不同的地球化学条件。缺氧沉积物中有孔虫基因的相对表达增加了一个数量级，这在10天的孵育实验中得到了证实，其中缺氧的发展与有孔虫蛋白编码转录物的相对丰度增加20-40倍相吻合，这主要归因于参与蛋白质合成、细胞内蛋白质运输和细胞骨架修饰的有孔虫。这表明，许多有孔虫在缺氧条件下不仅存活，而且茁壮成长。这些活性有孔虫的厌氧能量代谢的特点是糖和氨基酸的发酵，延胡索酸还原，和潜在的异化硝酸盐还原。此外，基因表达数据表明，在缺氧条件下，有孔虫利用磷酸肌酸作为ATP储存，从而维持高能磷酸盐库的储备，以应对无氧代谢过程中突然增加的能量需求。这与参与吞噬作用和网格蛋白介导的内吞作用（CME）的基因一起共表达。有孔虫除了通过吞噬作用摄取猎物细胞外，还可以利用CME将溶解的有机物作为碳源和能源。这些无氧代谢机制有助于解释有孔虫在5亿多年前寒武纪以来化石记录中的生态成功。
Foraminifera are single-celled eukaryotes (protists) of large ecological importance, as well as environmental and paleoenvironmental indicators and biostratigraphic tools. In addition, they are capable of surviving in anoxic marine environments where they represent a major component of the benthic community. However, the cellular adaptations of Foraminifera to the anoxic environment remain poorly constrained. We sampled an oxic-anoxic transition zone in marine sediments from the Namibian shelf, where the genera Bolivina and Stainforthia dominated the Foraminifera community, and use metatranscriptomics to characterize Foraminifera metabolism across the different geochemical conditions. Relative Foraminifera gene expression in anoxic sediment increased an order of magnitude, which was confirmed in a 10-day incubation experiment where the development of anoxia coincided with a 20–40-fold increase in the relative abundance of Foraminifera protein encoding transcripts, attributed primarily to those involved in protein synthesis, intracellular protein trafficking, and modification of the cytoskeleton. This indicated that many Foraminifera were not only surviving but thriving, under the anoxic conditions. The anaerobic energy metabolism of these active Foraminifera was characterized by fermentation of sugars and amino acids, fumarate reduction, and potentially dissimilatory nitrate reduction. Moreover, the gene expression data indicate that under anoxia Foraminifera use the phosphogen creatine phosphate as an ATP store, allowing reserves of high-energy phosphate pool to be maintained for sudden demands of increased energy during anaerobic metabolism. This was co-expressed alongside genes involved in phagocytosis and clathrin-mediated endocytosis (CME). Foraminifera may use CME to utilize dissolved organic matter as a carbon and energy source, in addition to ingestion of prey cells via phagocytosis. These anaerobic metabolic mechanisms help to explain the ecological success of Foraminifera documented in the fossil record since the Cambrian period more than 500 million years ago.
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DOI：
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发表时间：
2013-07
期刊：
--
影响因子：
--
作者：
B. Haas;A. Papanicolaou;M. Yassour;M. Grabherr;Philip D. Blood;Joshua C. Bowden;M. B. Couger;
通讯作者：
B. Haas;A. Papanicolaou;M. Yassour;M. Grabherr;Philip D. Blood;Joshua C. Bowden;M. B. Couger;
影响因子：
20.3
作者：
Stritt, Simon;Nurden, Paquita;Mumford, Andrew D.
通讯作者：
Mumford, Andrew D.
影响因子：
88.1
作者：
W. Orsi
通讯作者：
W. Orsi
影响因子：
3.4
作者：
Pichler M;Coskun ÖK;Ortega-Arbulú AS;Conci N;Wörheide G;Vargas S;Orsi WD
通讯作者：
Orsi WD
影响因子：
5.2
作者：
Kamp A;Høgslund S;Risgaard-Petersen N;Stief P
通讯作者：
Stief P