Bio-gene magnetite in organisms: its structure and putative function for orientation in the Earths magnetic field

生物体中的生物基因磁铁矿：其结构和在地球磁场中定向的推定功能

• 批准号: 255550953
• 负责人: Dr. Stephan Eder
• 金额: --
• 依托单位: Institut für Biologie und Umweltwissenschaften (IBU)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/255550953?language=en
• 关键词: Bio; gene; magnetite; organisms; its

The ferrimagnetic mineral magnetite (Fe3O4) occurs in the form of magnetosomes as intracellular biomineralization product in magnetotactic bacteria, where it provides the cells with the ability to swim along the Earths magnetic field lines. Since 1980, it has been suggested that magnetite also plays a key role as magnetoreception agent in the magnetic sense of higher organisms, particularly of migratory animals, which critically depend on a reliable sense of orientation. Indeed, magnetosome-like magnetite crystals were extracted from homogenized tissues of migratory fish species (salmon, tuna). However, it is still not clear whether these extracted magnetite crystals are involved in a magnetoreceptor structure, since the extraction technique used does not allow any interpretation on the cellular context of the magnetite crystals. Recently we succeeded in our efforts to gently extract and isolate intact cells with magnetic inclusions from the olfactory epithelium of rainbow trout. This method provides for the first time the possibility to study these candidate magnetoreceptor cells in more detail. In order to clarify the structure and function of these magnetic cells, we are planning to characterize the magnetic inclusions in terms of inner architecture, chemical composition and mineralogical nature with the aid of electron-micrographic techniques and micro-Raman-spectroscopy. In order to gain more insight into the magnetic structure of the inclusions, we will measure magnetic remanence curves of individual cells using alternating-field and pulse-field demagnetization techniques. Ferromagnetic resonance spectra will be used to screen tissue for magnetic signatures consistent with magnetosome structures in order to identify further candidate sites for magnetorceptor cells. Finally, we will investigate if magnetic field changes trigger physiological responses in these cells to test their putative magnetoreceptive nature. The information grained on the levels of structure, magnetism, and physiology, will be combined into a model of magnetite-based magnetoreception.

亚铁磁性矿物磁铁矿(Fe3O4)在趋磁细菌中以磁小体的形式存在，是细胞内生物矿化的产物，它为细胞提供了沿地球磁力线游泳的能力。自1980年以来，人们一直认为，磁铁矿在高等生物，特别是迁徙动物的磁感中也扮演着关键的角色，这些生物的磁感依赖于可靠的定向感。事实上，磁小体状的磁铁矿晶体是从迁徙鱼类(鲑鱼、金枪鱼)的匀浆组织中提取出来的。然而，目前尚不清楚这些提取的磁铁矿晶体是否与磁受体结构有关，因为所使用的提取技术不允许对磁铁矿晶体的细胞背景进行任何解释。最近，我们成功地从虹鱼的嗅觉上皮中温和地提取和分离出具有磁性包裹体的完整细胞。这种方法首次提供了更详细地研究这些候选磁感受器细胞的可能性。为了弄清这些磁性单元的结构和功能，我们计划借助电子显微技术和显微拉曼光谱对磁性包裹体的内部结构、化学成分和矿物学性质进行表征。为了更深入地了解包裹体的磁性结构，我们将使用交变磁场和脉冲场退磁技术测量单个晶胞的剩磁曲线。铁磁共振光谱将被用来筛选组织中与磁小体结构一致的磁性特征，以便确定更多的磁受体细胞的候选位置。最后，我们将研究磁场变化是否会在这些细胞中触发生理反应，以测试它们假定的磁感受性。将在结构、磁性和生理水平上颗粒化的信息组合成基于磁铁矿的磁接收模型。