Collaborative Research: Biophysical Analysis of Magnetosome Development in Magnetotactic Bacteria Under Ambient Conditions

许多生物体生存的核心是它们能够将无机分子加工成精细的晶体结构，如骨骼，牙齿和保护壳。 这种无处不在的“生物矿化”过程取决于细胞内专门蛋白质的精确作用，以在需要的地方形成矿物质，并防止它们在敏感组织中积累。 虽然已经取得了进展，但关于生物矿化如何在单个细胞内实现以及哪些基因控制该过程还不清楚。 该合作项目将通过将磁成像技术的最新进展应用于简单和良好控制的生物系统中的生物矿化的详细研究来应对这一挑战：在趋磁细菌（MTB）内生产纳米级磁性颗粒，以及MTB使用这些颗粒链（称为磁小体）沿着地球磁场线（称为趋磁性）定向和旅行。 在该项目期间，学生和博士后研究人员将接受物理和生命科学接口的科学实践培训。 此外，该项目可能会通知具有广泛的实际意义的改进材料的开发，因为生物矿化的产品具有上级性能相比，目前由人类工程。该项目的科学目标是研究生物矿化的分子机制和MTB中磁性纳米颗粒的发展。 这些研究将采用一种“钻石磁成像仪”，该成像仪利用钻石芯片表面的纳米级量子传感器层，能够在实验室环境条件下对人群中单个MTB的磁场模式进行成像，空间分辨率超过50纳米，视野大于1毫米。 研究人员将应用金刚石磁成像仪研究各种MTB物种和生物矿化突变体中的磁性纳米颗粒生长。 该项目将为实现趋磁性的物理过程打开一个新的窗口，包括磁性纳米颗粒在磁性纳米颗粒生长过程中从超顺磁性到稳定的单畴磁性状态的转变，以及单个MTB中磁性纳米颗粒之间相互作用的作用。 对遗传突变体的磁性测量将为控制生物矿化过程的基因提供生物学见解。 还将通过对不同MTB的时间序列磁性测量以及对单个活MTB的磁性成像来观察细胞分裂周期期间磁性纳米颗粒链的动态。

Central to the survival of many organisms is their ability to manipulate inorganic molecules into elaborate crystalline structures such as skeletons, teeth, and protective shells. This ubiquitous process of "biomineralization" depends on the precise action of specialized proteins within cells to form minerals where they are needed and prevent their accumulation in sensitive tissues. Although progress has been made, much is not understood about how biomineralization is realized inside of individual cells and which genes control the process. This collaborative project will address this challenge by applying recent advances in magnetic imaging technology to detailed studies of biomineralization in a simple and well-controlled biological system: the production of nanoscale magnetic particles within magnetotactic bacteria (MTB), and the use by MTB of chains of these particles (known as magnetosomes) for orientation and travel along the Earth's magnetic field lines (known as magnetotaxis). During this project, students and postdoctoral researchers will receive training in scientific practices at the interface of the physical and life sciences. In addition, the project may inform the development of improved materials with broad practical relevance, as products of biomineralization have superior properties compared to those currently engineered by humans.The scientific goals of this project are to study the molecular mechanisms governing biomineralization and the development of magnetic nanoparticles in MTB. The studies will employ a "diamond magnetic imager" that exploits a nanoscale layer of quantum sensors at the surface of a diamond chip, enabling imaging of magnetic field patterns from individual MTB in a population under ambient laboratory conditions, with better than 50 nanometer spatial resolution and greater than 1 millimeter field-of-view. The investigators will apply the diamond magnetic imager to studies of magnetic nanoparticle growth in various MTB species and biomineralization mutants. The project will open a new window onto the physical processes enabling magnetotaxis, including the transition of magnetic nanoparticles from a superparamagnetic to a stable single-domain magnetic state during magnetic nanoparticle growth, and the role of interactions between magnetic nanoparticles within individual MTB. Magnetic measurements on genetic mutants will provide biological insights into the genes controlling the biomineralization process. Observations will also be made of the dynamics of the magnetic nanoparticle chain during the cell division cycle, both through time series magnetic measurements on different MTB as well as magnetic imaging of individual living MTB.