d-Amino acids (d-AAs) are endogenous molecules found throughout the metazoan, the functions of which remain poorly understood. Measurements of low abundance and heterogeneously distributed d-AAs in complex biological samples, such as cells and multicellular structures of the central nervous system (CNS), require the implementation of sensitive and selective analytical approaches. In order to measure the d- and l-forms of aspartate and glutamate, we developed and applied a stacking chiral capillary electrophoresis (CE) with laser-induced fluorescence detection method. The achieved online analyte preconcentration led to a 480-fold enhancement of detection sensitivity relative to capillary zone electrophoresis, without impacting separation resolution or analysis time. Additionally, the effects of inorganic ions on sample preconcentration and CE separation were evaluated. The approach enabled the relative quantification of d-aspartate and d-glutamate in individual neurons mechanically isolated from the CNS of the sea slug Aplysia californica, a well characterized neurobiological model. Levels of these structurally similar d-AAs were significantly different in subpopulations of cells collected from the investigated neuronal clusters.

中文翻译：

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大体积样品堆积毛细管电泳手性测量单个神经元中的天冬氨酸和谷氨酸

d-氨基酸（d -AAs）是在整个后生动物中发现的内源性分子，其功能仍知之甚少。对复杂生物样品（例如中枢神经系统（CNS）的细胞和多细胞结构）中的低丰度和异质分布的d- AA进行测量需要实施灵敏且选择性的分析方法。为了测量d-和l形式的天冬氨酸和谷氨酸，我们开发并应用了堆叠手性毛细管电泳（CE）激光诱导荧光检测方法。相对于毛细管区带电泳，已实现的在线分析物预富集导致检测灵敏度提高了480倍，而不会影响分离分辨率或分析时间。此外，还评估了无机离子对样品预富集和CE分离的影响。该方法可以对从海Aplysia californica（一种功能齐全的神经生物学模型）的中枢神经系统机械分离的单个神经元中的d-天冬氨酸和d-谷氨酸进行相对定量。这些结构上相似的水平d从研究的神经元簇收集的细胞亚群中，-AAs显着不同。