Closed-system behaviour of the intra-crystalline fraction of amino acids in mollusc shells.
Closed-system behaviour of the intra-crystalline fraction of amino acids in mollusc shells.
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DOI：
10.1016/j.quageo.2007.07.001
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发表时间：
2008-02
影响因子：
2.7
通讯作者：
Collins MJ
中科院分区：
文献类型：
--
作者：
Penkman KE;Kaufman DS;Maddy D;Collins MJ
当软体动物壳进行分析，传统的氨基酸地质年代学，包括整个人口的氨基酸，晶间和晶内。本研究探讨了去除最容易受到环境影响的氨基酸的效用，通过分离包裹在软体动物壳的矿物晶体内的氨基酸部分（晶内部分）。漂白，加热和浸出（扩散损失）实验进行了现代和化石Corbicula fluminalis，Margaritifera falcata，Bithynia tentaculata和Valvata piscinalis贝壳。暴露的粉末状软体动物壳浓缩NaOCl 48小时有效地减少了四个类群的氨基酸含量的残留水平，假设代表的晶内馏分。当在140 °C的水中加热24小时时，只有1%的氨基酸从现代贝壳的晶内部分中浸出，而从整个贝壳中浸出的氨基酸为40%。游离氨基酸更有效地保留在晶内级分中，在140 °C下24 h后占整个壳的55%（相比之下为18%）。对于化石腹足类，壳间变异的D/L值内的晶体部分的一个单一的年龄人口减少了50%，与传统分析的外壳。相反，对C. fluminalis似乎没有改善这一分类群的结果，可能是由于壳超微结构的变异。尽管如此，腹足类中的晶内组分近似于一个封闭的氨基酸系统，并且似乎为地质年代学应用提供了一个上级氨基酸子集。
When mollusc shells are analysed conventionally for amino acid geochronology, the entire population of amino acids is included, both inter- and intra-crystalline. This study investigates the utility of removing the amino acids that are most susceptible to environmental effects by isolating the fraction of amino acids encapsulated within mineral crystals of mollusc shells (intra-crystalline fraction). Bleaching, heating and leaching (diffusive loss) experiments were undertaken on modern and fossil Corbicula fluminalis, Margaritifera falcata, Bithynia tentaculata and Valvata piscinalis shells. Exposure of powdered mollusc shells to concentrated NaOCl for 48 h effectively reduced the amino acid content of the four taxa to a residual level, assumed to represent the intra-crystalline fraction. When heated in water at 140 °C for 24 h, only 1% of amino acids were leached from the intra-crystalline fraction of modern shells compared with 40% from whole shell. Free amino acids were more effectively retained in the intra-crystalline fraction, comprising 55% (compared with 18%) of the whole shell after 24 h at 140 °C. For fossil gastropods, the inter-shell variability in D/L values for the intra-crystalline fraction of a single-age population was reduced by 50% compared with conventionally analysed shells. In contrast, analysis of the intra-crystalline fraction of C. fluminalis does not appear to improve the results for this taxon, possibly due to variability in shell ultrastructure. Nonetheless, the intra-crystalline fraction in gastropods approximates a closed system of amino acids and appears to provide a superior subset of amino acids for geochronological applications.
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DOI：
10.1016/s0065-3233(08)60388-5
发表时间：
1965-01-01
期刊：
ADVANCE PROTEIN CHEM
影响因子：
--
作者：
HILL, ROBERT L.
通讯作者：
HILL, ROBERT L.
影响因子：
2.7
作者：
Kaufman, Darrell S.
通讯作者：
Kaufman, Darrell S.
影响因子：
4
作者：
Kaufman, DS;Manley, WF
通讯作者：
Manley, WF
影响因子：
56.9
作者：
BERMAN, A;HANSON, J;ADDADI, L
通讯作者：
ADDADI, L
影响因子：
64.8
作者：
BOWEN, DQ;HUGHES, S;MILLER, GH
通讯作者：
MILLER, GH