| Analysis of N-acetylmuramic acid-6-phosphate (MurNAc-6P) Accumulation by HPLC-MS
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Author:
Date:
2017-08-05
[Abstract] We describe here in detail a high-performance liquid chromatography-mass spectrometry (HPLC-MS)-based method to determine N-acetylmuramic acid-6-phosphate (MurNAc-6P) in bacterial cell extracts. The method can be applied to both Gram-negative and Gram-positive bacteria, and as an example we use Escherichia coli cells in this study. Wild type and mutant cells are grown for a defined time in a medium of choice and harvested by centrifugation. Then the cells are disintegrated and soluble cell extracts are generated. After removal of proteins by precipitation with acetone, the extracts are analyzed by HPLC-MS. Base peak chromatograms of wild type and mutant cell extracts are used to determine a differential ion spectrum that reveals differences in the MurNAc-6P content of ...
[摘要] 我们在这里详细描述了一种基于高效液相色谱 - 质谱（HPLC-MS）的方法，以确定细菌细胞提取物中的N-乙酰谷氨酸-6-磷酸（MurNAc-6P）。该方法可以应用于革兰氏阴性菌和革兰氏阳性菌，作为一个例子，我们在本研究中使用大肠杆菌细胞。野生型和突变型细胞在选择的培养基中生长一定时间并通过离心收获。然后细胞分解并产生可溶性细胞提取物。通过用丙酮沉淀除去蛋白质后，通过HPLC-MS分析提取物。野生型和突变型细胞提取物的基本峰图谱用于测定显示两种样品中MurNAc-6P含量差异的差异离子谱。确定阴离子模式下MurNAc-6P（（MH）= 372.070m/z的提取色谱图的峰面积允许定量使用的MurNAc-6P水平计算消泡聚糖的MurNAc含量的回收率。
【背景】在细菌生长期间，大部分细菌的肽聚糖细胞壁稳定地翻转并可能回收（再循环）。 肽聚糖回收代谢的关键化合物是积聚在大肠杆菌的MurNAc-6P醚酶（MurQ）突变体中的N-乙酰谷氨酸-6-磷酸（MurNAc-6P） （Jaeger等人，2005; Uehara等人，2006）。 MurQ直向同源物被发现在许多细菌中，包括革兰氏阳性菌（Litzinger等人，2010; Reith和Mayer，2011）。 ...
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| Carotenoid Extraction and Quantification from Capsicum annuum
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Author:
Date:
2014-10-05
[Abstract] Carotenoids are ubiquitous pigments that play key roles in photosynthesis and also accumulate to high levels in fruit and flowers. Specific carotenoids play essential roles in human health as these compounds are precursors for Vitamin A; other specific carotenoids are important sources of macular pigments and all carotenoids are important anti-oxidants. Accurate determination of the composition and concentration of this complex set of natural products is therefore important in many different scientific areas. One of the richest sources of these compounds is the fruit of Capsicum; these red, yellow and orange fruit accumulate multiple carotenes and xanthophylls. This report describes the detailed method for the extraction and quantification of specific carotenes and xanthophylls.
[摘要] 类胡萝卜素是在光合作用中起关键作用的普遍存在的颜料，并且在果实和花中积累到高水平。 特定类胡萝卜素在人类健康中起着重要作用，因为这些化合物是维生素A的前体; 其他特定类胡萝卜素是黄斑色素的重要来源，并且所有类胡萝卜素是重要的抗氧化剂。 因此，在许多不同的科学领域中，精确测定天然产物的复杂集合的组成和浓度是重要的。 这些化合物最丰富的来源之一是辣椒的果实。 这些红色，黄色和橙色果实积累多个胡萝卜素和叶黄素。 本报告描述了特定胡萝卜素和叶黄素的提取和定量的详细方法。
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