果蝇识别爆炸物分子的嗅觉识别机制研究

Organisms have highly sensitive and accurate discrimination capacity for sensing odorants in the environment through olfactory receptors. It has been reported that many organisms including Drosophila could detect explosives which are of nonnatural origin. However, the identification mechanisms are still unknown. The present work will use Drosophila melanogaster as an animal model to investigate the olfactory identification mechanisms for explosives. Firstly, several important explosives-sensitive olfactory receptors in Drosophila will be cloned and expressed in Xenopus leaevis oocytes, in which the responsiveness of olfactory receptors for explosives as well as natural odorants will be detected by calcium imaging and electrophysiological techniques. Secondly, the selected explosives or natural odorants, which can stimulate above olfactory receptors, will be compared and analyzed for the common features of their structures and functions. Furthermore, a series of olfactory receptor mutants will be prepared following the instruction of bioinformatics, and the changes of olfactory detection capacity of these mutants will be studied, in order to get detailed information about the key odorant binding zone or significant amino acid positions in the olfactory receptors. This study will illustrate the olfactory identification mechanisms of explosives-sensitive olfactory receptors in Drosophila, and will promote the further development of biomimetic sensor field.

生物通过嗅觉受体来灵敏和准确地识别环境中的气味分子。研究表明，包括果蝇在内的多种生物对非天然存在的爆炸物分子具有特异性反应的能力，然而其感受爆炸物分子的嗅觉识别机制仍然未知。本项目拟以果蝇为模型，克隆并通过爪蟾卵母细胞异源表达爆炸物敏感的嗅受体蛋白，运用钙成像法、电生理技术检测其对系列爆炸物分子和天然气味分子的识别能力；同时，筛选激活嗅受体识别反应的爆炸物及天然气味分子，分析其结构、功能性质的异同以及嗅受体蛋白的分子识别共性；进一步地，结合生物信息学预测以及制备蛋白突变的方法，研究嗅受体突变蛋白嗅觉识别能力的改变，从而获得受体蛋白嗅觉识别的特异性氨基酸位点或关键肽段信息，以期掌握上述爆炸物敏感嗅受体蛋白的嗅觉识别规律。研究结果有助于揭示果蝇嗅受体蛋白识别非天然存在爆炸物分子的嗅觉机制，并为敏感嗅受体蛋白在仿生嗅觉探测领域的潜在应用提供理论基础。

生物通过嗅觉受体来灵敏和准确地识别环境中的气味分子。研究表明，包括果蝇在内的多种生物对非天然存在的爆炸物分子具有特异性反应的能力，然而其感受爆炸物分子的嗅觉识别机制仍然未知。本项目以果蝇为模型，特异性克隆爆炸物敏感的嗅受体基因，摸索并优化对上述7次跨膜的嗅受体蛋白的异源表达条件。在按照研究计划尝试爪蟾卵母细胞异源表达嗅受体蛋白的同时，根据实际情况调整并拓展了研究思路，探索性地运用基于大肠杆菌提取物的无细胞蛋白表达平台，对爆炸物敏感嗅受体蛋白进行体外表达。摸索了不同种类去污剂的添加条件，并优化了添加去污剂的最佳浓度，获得了嗅受体蛋白的高可溶性表达，为后续嗅受体结构、功能的研究提供新的途径。同时，对激活嗅受体识别反应的爆炸物及天然气味分子进行比对分析，探讨其结构、功能性质的异同以及嗅受体蛋白的分子识别共性，以期掌握上述爆炸物敏感嗅受体蛋白的嗅觉识别规律。相关研究摸索了对外源嗅受体蛋白进行无细胞体系表达的优化条件，获得了对高危爆炸物挥发性气体敏感的嗅受体蛋白；初步分析了激活敏感嗅受体蛋白响应的气味分子的结构特性。研究结果有助于揭示果蝇嗅受体蛋白识别非天然存在爆炸物分子的嗅觉机制，并为敏感嗅受体蛋白在仿生嗅觉探测领域的潜在应用提供理论基础。