Molecular mechanisms of bacterial magneto-aerotaxis

细菌磁趋气的分子机制

• 批准号: 525457187
• 负责人: Dr. Daniel Pfeiffer
• 金额: --
• 依托单位: Lehrstuhl für Mikrobiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/525457187?language=en
• 关键词: Molecular; mechanisms; bacterial; magneto; aerotaxis

Magnetotactic bacteria (MTB) possess the unique ability to navigate using the Earth’s magnetic field. Magnetic navigation results from the passive magnetic alignment of cells based on the synthesis of magnetosomes, intracellular membrane-enveloped crystals of a magnetic iron mineral arranged in chains, and active motility utilizing flagella. Magnetic alignment is believed to facilitate orientation within aquatic habitats towards growth-favoring oxygen concentrations, a behavior known as magneto-aerotaxis. However, the molecular mechanisms controlling this unique motility pattern, which differs significantly from those of well-studied model organisms like Escherichia coli, are poorly understood. In particular, it is unknown if and how the perception of magnetic fields and oxygen gradients is integrated via the complex chemosensory network in MTB to control flagellar motor output. To study the molecular mechanisms of bacterial magneto-aerotaxis, I established fluorescent labeling of flagella in the genetically tractable polarly flagellated MTB Magnetospirillum gryphiswaldense. In the proposed project, this method will be used to determine how the chemosensory system coordinates flagellar motors in magnetospirilla - a question that has not been solved and for which contradicting models have been postulated (including non-magnetic bipolarly flagellated spirilla), such as the rotation of opposing flagellar motors in opposite senses, in the same direction, or pausing of motors. Additional aims will be to unravel how environmental signals and parameters (such as the oxygen gradient, the ambient magnetic field, or the environmental structure) affect flagellar motor output, polar assembly of flagella, and directional motility in magnetic fields (so-called North-/South-seeking magneto-aerotaxis). Ultimately, this project will yield a breakthrough in the understanding of the molecular principles that govern magnetic navigation in bacteria. Expected findings will also have broader implications related to bacterial motility and microbial cell biology, such as complex bacterial signal transduction systems, flagellar assembly and motor control in polar flagellates (including many clinically relevant pathogens), and how population heterogeneity and different motility patterns relate to the selective advantage in complex environments. Finally, a comprehensive understanding of magneto-aerotaxis may open the door for future applications in synthetic biology, such as the targeted modification of MTB and the engineering of magnetic navigation for microrobotic applications.

趋磁细菌（MTB）具有利用地球磁场导航的独特能力。磁导航是基于磁小体的合成、排列在链中的磁性铁矿物的细胞内膜包膜晶体和利用鞭毛的主动运动性的细胞的被动磁性排列的结果。磁性排列被认为是促进水生栖息地内朝向有利于生长的氧气浓度的方向，这种行为被称为磁趋气性。然而，控制这种独特的运动模式的分子机制，这与那些研究充分的模式生物，如大肠杆菌，显着不同，知之甚少。特别是，它是未知的，如果和如何磁场和氧梯度的感知是通过复杂的化学感受网络集成在MTB控制鞭毛电机输出。为了研究细菌磁趋氧性的分子机制，我建立了荧光标记的鞭毛在遗传上易处理的极性鞭毛MTB Magnetocellum gryphiswaldense。在拟议的项目中，这种方法将被用来确定化学传感系统如何协调鞭毛马达在磁鞭毛-一个尚未解决的问题，并已假设矛盾的模型（包括非磁性双极鞭毛鞭毛），如相对的鞭毛马达在相反的意义上，在同一方向旋转，或暂停电机。其他目标将是解开环境信号和参数（如氧气梯度，环境磁场，或环境结构）如何影响鞭毛电机输出，极性组装的鞭毛，和磁场中的定向运动（所谓的北/南寻求磁趋气性）。最终，该项目将在理解细菌中磁导航的分子原理方面取得突破。预期的研究结果也将有更广泛的影响有关的细菌运动和微生物细胞生物学，如复杂的细菌信号转导系统，鞭毛组装和电机控制极性鞭毛虫（包括许多临床相关的病原体），以及如何人口异质性和不同的运动模式与复杂环境中的选择优势。最后，对磁趋空性的全面了解可能为合成生物学的未来应用打开大门，例如MTB的靶向修饰和微机器人应用的磁导航工程。