NEW PROBES AND REAGENTS FOR BIOLOGICAL STUDIES

首席研究员整体研究计划的中心主题 是设计、化学合成、表征和协作 新探针和试剂在生物学研究中的应用 系统. 五个子领域构成了这个五年项目的重点。 （a）新的 基于氮氧自由基的分子pH指示剂。 内部pH值的测量 细胞和囊泡是许多生物学研究的基础。 流程. 我们建议将我们的α-氨基氮氧化物系列扩展为 pH依赖性ESR超精细分裂常数aN包括那些 在pH 6-8范围内反应最佳。 B）新的氮氧取代的冠醚 乙醚 测定细胞内钠离子和钙离子的活性 钾离子是膜离子转运的分子研究的中心 细胞生物学的过程。 我们设想了一系列氮氧自旋标记 冠醚和穴状配体，其中aN是敏感的活动， 在生理上感兴趣的浓度范围内的金属离子， 建立了一种新的、高灵敏度的测定离子的ESR方法 活动 c）新的小型高电子密度EM标记。 高分辨率 EM生物学研究需要开发更小的、高度电子化的 能够附着于大分子上特定位点的致密标记。 有机功能化的杂多钨酸盐离子在这方面具有很高的前景。 请注意。 这些标记中的几种的合成和应用是 提出了 d）一种新的单重态氧ESR探针。 单氧是一种 可能的氧化剂与光动力学效应在生物 系统. 我们打算研制蒽氮氧化合物作为灵敏的ESR 通过与ESR相关的内过氧化物形成来探测该氧化剂 光谱变化 e）新的基于氮氧自由基的核磁共振全身医学成像 剂. 核磁共振在全身医学成像中的应用正在经历 爆炸性发展。 增强器官之间对比度的试剂是 needed. 氮氧化物可能是答案，如果抵抗原位还原 可以被构建到分子中。 这是我们的目标。 意义 这项研究项目的目的是提供新的分子， 旨在克服目前生物学领域的一些严重障碍， 和医学研究。

The central theme of the principal investigator's overall research program is the design, chemical synthesis, characterization and collaborative application of new probes and reagents for the study of biological systems. Five subareas form the focus of this five year project. a) New Nitroxide-Based Molecular pH Indicators. The measurement of pH inside cells and vesicles is fundamental to the study of many biological processes. We propose to extend our series of Alpha-amino notroxides with pH dependent ESR hyperfine splitting constants aN to include those which respond optimally in the range pH 6-8. b) New Nitroxide Substituted Crown Ethers. Measurement of the intracellular activities of sodium and potassium ions is central to molecular studies of membrane ion transport processes in cell biology. We envisage a series of nitroxide spin labeled crown ethers and cryptands in which aN is sensitive to the activity of the metal ion in the physiologically interesting concentration range, constituting a new, highly sensitive ESR method for determination of ion activities. c) New Small Highly Electron Dense EM labels. High resolution EM biological studies require the development of smaller, highly electron dense labels capable of attachment to specific sites on a macromolecule. Organic functionalized heteropolytungstate ions hold high promise in this regard. The synthesis and application of several of these labels is proposed. d) A New ESR Probe for Singlet Oxygen. Single oxygen is a likely oxidant associated with the photodynamic effect in biological systems. We intend to develop anthracene nitroxides as sensitive ESR probes for this oxidant through endoperoxide formation with associated ESR spectral changes. e) New Nitroxide-Based NMR Whole Body Medical Imaging Agents. The use of NMR for whole body medical imaging is undergoing explosive development. Agents which enhance contrast between organs are needed. Nitroxides may be the answer if resistance to in situ reduction can be built into the molecules. This is our objective. The significance of this research project is to make available new molecules which have been designed to overcome some of the currently serious obstacles in biological and medical research.