Biomineralisation by earthworms - an investigation into the stability and distribution of amorphous calcium carbonate.
Biomineralisation by earthworms - an investigation into the stability and distribution of amorphous calcium carbonate.
复制标题
DOI：
10.1186/s12932-015-0019-z
复制
发表时间：
2015
影响因子：
2.3
通讯作者：
Versteegh EA
中科院分区：
文献类型：
--
作者：
Hodson ME;Benning LG;Demarchi B;Penkman KE;Rodriguez-Blanco JD;Schofield PF;Versteegh EA
许多生物矿物是由无定形碳酸钙(ACC)形成的，但以无机方式合成纯碳酸钙时，这一相非常不稳定。几种蚯蚓分泌含有高度稳定的ACC的碳酸钙颗粒。我们分析了形成颗粒的乳状液和固体颗粒的氨基酸组成(用液相色谱)和官能团组成(用傅立叶变换红外光谱)。采用电感耦合等离子体发射光谱(ICPOES)和电子探针分析(EMPA)对颗粒元素组成进行了分析。用FTIR对固体颗粒中ACC的质量进行了定量，并与颗粒的元素和氨基酸组成进行了比较。颗粒的散装分析为粉状散装材料。空间分辨分析是使用基于同步加速器的μ-FTIR和EMPA电子探针分析颗粒的薄片。形成颗粒的乳状液富含氨基酸(每种氨基酸的≤为136±3nmoL mg−1(n=3；±std dev))，CaCO_3相为ACC。即使在生产四年后，颗粒也含有ACC。ACC的质量与颗粒元素组成之间不存在相关性。颗粒氨基酸浓度与ACC含量有很好的相关性(r≥0.7，p≤0.0 5)，与氨基酸(或其组成的蛋白质)在ACC稳定中的作用一致。同一蚯蚓生产的颗粒的ACC(RSD=16%)和氨基酸浓度(RSD=22-35%)具有较高的颗粒内变异。基于同步加速器的μ-FTIR颗粒薄片分布图和ν2：ν4峰比的相对强度图，以及使用ACC和方解石标准进行的聚类分析和成分回归，显示了可能的ACC富集区和方解石富集区的相似的空间分布。我们不能识别μ-FTIR光谱中的有机峰，因此不能确定ACc富含结构域是否也具有相对较高的氨基酸浓度。Acc分布与EMPA测定的元素浓度之间不存在相关性。蚯蚓碳酸钙颗粒中的ACC具有很高的稳定性。我们的结果表明，氨基酸(或蛋白质)在这种稳定性中发挥了作用。我们没有看到通过加入无机成分来稳定ACC的证据。利用同步加速器μ-FTIR图谱研究了蚯蚓产碳酸钙颗粒中无定形碳酸钙的空间分布。本文的在线版本(doi：10.1186/s12932-0150019-z)包含补充材料，授权用户可以使用。
Many biominerals form from amorphous calcium carbonate (ACC), but this phase is highly unstable when synthesised in its pure form inorganically. Several species of earthworm secrete calcium carbonate granules which contain highly stable ACC. We analysed the milky fluid from which granules form and solid granules for amino acid (by liquid chromatography) and functional group (by Fourier transform infrared (FTIR) spectroscopy) compositions. Granule elemental composition was determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and electron microprobe analysis (EMPA). Mass of ACC present in solid granules was quantified using FTIR and compared to granule elemental and amino acid compositions. Bulk analysis of granules was of powdered bulk material. Spatially resolved analysis was of thin sections of granules using synchrotron-based μ-FTIR and EMPA electron microprobe analysis. The milky fluid from which granules form is amino acid-rich (≤ 136 ± 3 nmol mg−1 (n = 3; ± std dev) per individual amino acid); the CaCO3 phase present is ACC. Even four years after production, granules contain ACC. No correlation exists between mass of ACC present and granule elemental composition. Granule amino acid concentrations correlate well with ACC content (r ≥ 0.7, p ≤ 0.05) consistent with a role for amino acids (or the proteins they make up) in ACC stabilisation. Intra-granule variation in ACC (RSD = 16%) and amino acid concentration (RSD = 22–35%) was high for granules produced by the same earthworm. Maps of ACC distribution produced using synchrotron-based μ-FTIR mapping of granule thin sections and the relative intensity of the ν2: ν4 peak ratio, cluster analysis and component regression using ACC and calcite standards showed similar spatial distributions of likely ACC-rich and calcite-rich areas. We could not identify organic peaks in the μ-FTIR spectra and thus could not determine whether ACC-rich domains also had relatively high amino acid concentrations. No correlation exists between ACC distribution and elemental concentrations determined by EMPA. ACC present in earthworm CaCO3 granules is highly stable. Our results suggest a role for amino acids (or proteins) in this stability. We see no evidence for stabilisation of ACC by incorporation of inorganic components. Synchrotron-based μ-FTIR mapping was used to determine the spatial distribution of amorphous calcium carbonate in earthworm-produced CaCO3 granules. The online version of this article (doi:10.1186/s12932-015-0019-z) contains supplementary material, which is available to authorized users.
登录
查看更多内容
影响因子：
2.7
作者：
Demarchi B;Rogers K;Fa DA;Finlayson CJ;Milner N;Penkman KE
通讯作者：
Penkman KE
影响因子：
3.8
作者：
Beck, Ralf;Andreassen, Jens-Petter
通讯作者：
Andreassen, Jens-Petter
影响因子：
2.5
作者：
Brinza, Loredana;Schofield, Paul F.;Mosselmans, J. Frederick W.
通讯作者：
Mosselmans, J. Frederick W.
影响因子：
2.7
作者：
Briones, M. J. I.;Lopez, E.;Gago-Duport, L.
通讯作者：
Gago-Duport, L.
影响因子：
3.5
作者：
Cobourne, G.;Mountjoy, G.;Plaisier, J. R.
通讯作者：
Plaisier, J. R.