Biological control over the formation and storage of amorphous calcium carbonate by earthworms
Biological control over the formation and storage of amorphous calcium carbonate by earthworms
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DOI：
10.1180/minmag.2008.072.1.227
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发表时间：
2008-02-01
影响因子：
2.7
通讯作者：
Gago-Duport, L.
中科院分区：
文献类型：
--
作者：
Briones, M. J. I.;Lopez, E.;Gago-Duport, L.
含钙腺产生碳酸钙的浓缩悬浮液，在某些物种中沉淀为CaCO 3的凝结物，然后进入土壤。在这里，我们研究了CaCO 3形成的初始阶段的蚯蚓友好的傅立叶变换红外和电子显微镜技术（场发射扫描电子显微镜，透射电子显微镜，高分辨率电子显微镜和选区电子衍射）。此外，水溶性的碳酸酐酶（CA）和腺体分泌（“乳状液”）的红外光谱之间的比较进行，以探讨CaCO 3沉淀的机制。我们的研究结果强烈表明，碳酸化开始与溶解的CO2，这是通过去质子化转化为HCO 3-，然后到CO 32-，最后到无定形碳酸钙（ACC）。虽然ACC稳定发生在生物控制下，进一步的转化阶段，导致方解石结核似乎是无机驱动的奥斯特瓦尔德熟化过程。
The earthworm calciferous gland produces a concentrated suspension of calcium carbonate and in certain species precipitates as concretions of CaCO3, which then enter the soil. Here we investigated the initial stages of CaCO3 formation in the earthworm Lumbricus friendi by means of Fourier transform infrared and electron microscopy techniques (field-emission scanning electron microscopy, transmission electron microscopy, high resolution electron microscopy and selected area electron diffraction). In addition, comparisons between the IR spectra of the water-dissolved carbonic anhydrase (CA) and the glandular secretion ('milky fluid') were performed in order to investigate the mechanisms involved in CaCO3 precipitation. Our results strongly suggest that carbonation starts with the dissolved CO2, which is transformed via deprotonation to HCO3-, then to CO32- and finally to amorphous calcium carbonate (ACC). While ACC stabilization takes place under the biological control, further transformation stages leading to calcite concretions seem to be inorganically driven by an Ostwald ripening process.