Effects of decalcification on bulk and compound-specific nitrogen and carbon isotope analyses of dentin: Effects of decalcification on isotope analyses of dentin
Effects of decalcification on bulk and compound-specific nitrogen and carbon isotope analyses of dentin: Effects of decalcification on isotope analyses of dentin
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脱钙对牙本质整体和化合物特异性氮和碳同位素分析的影响：脱钙对牙本质同位素分析的影响
DOI：
10.1002/rcm.7073
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发表时间：
2014
影响因子：
2
通讯作者：
McCarthy, Matthew D.
中科院分区：
文献类型：
--
作者：
Brault, Emily K.;Koch, Paul L.;Gier, Elizabeth;Ruiz-Cooley, R. I.;Zupcic, Jessica;Gilbert, Kwasi N.;McCarthy, Matthew D.
理由：对于牙本质的大量碳和氮同位素分析，样品通常是脱钙的。由于牙本质中的非蛋白碳含量较低，因此全样品分析可以得到可靠的数据。骨和牙本质蛋白质的化合物特异性同位素分析（CSIA）是重建现代和过去食物网中碳和氮流动的有力工具。脱钙也被用于制备CSIA的骨和牙本质样品，但这一过程对总体牙本质、氨基酸组成及其特定同位素值的影响尚不清楚。方法测定抹香鲸牙齿中原牙本质和脱钙牙本质的体积同位素值，以确定脱钙的影响和未经处理的牙本质结果的准确性。CSIA还对脱钙牙本质和原始牙本质进行了CSIA，以检查两种方法之间氨基酸同位素值和臼齿组成的差异。结果对原始牙本质进行分析，得到了该动物精确的体积同位素测量结果。脱钙样品和原牙本质中单个氨基酸的同位素值相似，但两种样品之间同位素值偏移的平均值显著。无机物质的存在使原始样品的氨基酸同位素值处理复杂化，并可能导致脱钙样品和原始样品之间的同位素差异。结论该现代牙本质中脂质和碳酸盐浓度较低，牙本质蛋白质和碳酸盐碳同位素值相近，不需要脱钙化来测量牙本质的体积同位素值。这种方法不适用于某些情况（例如，化石牙本质和现代骨骼）。脱钙仍然应该在CSIA之前使用，因为在原始牙本质处理过程中会出现明显的基质问题，而且脱钙不会改变牙本质的氨基酸摩尔组成或同位素值。版权所有©2014 John Wiley & Sons， Ltd。
RATIONALEFor bulk carbon and nitrogen isotope analysis of dentin, samples are typically decalcified. Since the non‐protein carbon in dentin is low, whole sample analysis may produce reliable data. Compound‐specific isotope analysis (CSIA) of bone and tooth dentin protein is a powerful tool for reconstructing the flow of carbon and nitrogen in modern and past food webs. Decalcification has also been used to prepare bone and dentin samples for CSIA, but the effects of this process on bulk dentin, amino acid composition, and their specific isotope values are not known.METHODSThe bulk isotope values of raw and decalcified dentin from a sperm whale tooth were measured to determine the effects of decalcification and the accuracy of untreated dentin results. CSIA was also performed on decalcified and raw dentin to examine differences in the amino acid isotope values and molar composition between these two approaches.RESULTSAnalysis of raw dentin yields precise and accurate bulk isotope measurements for this animal. The isotopic values of decalcified samples and raw dentin for individual amino acids were similar, but the average of the isotope value offsets between the two sample types was significant. The presence of inorganic material complicated raw sample processing for individual amino acid isotope values, and may have contributed to the isotopic differences between decalcified and raw samples.CONCLUSIONSDecalcification is not needed to measure bulk isotope values in dentin from this modern odontocete, probably because the lipid and carbonate concentrations are low and the carbon isotope values of dentin protein and carbonate are similar. This method should not be applied in some cases (e.g., with fossil dentin and modern bone). Decalcification should still be used prior to CSIA since significant matrix issues occur with raw dentin processing and decalcification does not alter the amino acid molar composition or isotopic values of dentin. Copyright © 2014 John Wiley & Sons, Ltd.