Manipulation of Cell Division with Static Magnetic Fields

虽然有丝分裂和胞质分裂的许多方面已经阐明，大量正在进行的工作集中在这些基本过程中，显示出仍有许多发现和解决方案。显微镜和免疫细胞化学以及细胞及其组分的机械、光学和生物化学操作技术的进步传统上导致并继续导致该领域的实质性进展。Valles及其同事最近发现，非洲爪蟾（Xenopus laevis）胚胎的早期分裂（细胞分裂）与一个大的静磁场相一致。解理的重定向系统地依赖于场强和取向，而不依赖于场梯度。这一新发现为解剖细胞与磁场之间的相互作用提供了机会，并可能开发出操纵细胞和研究细胞分裂的新工具。具体目标1：确定解理面重定向机制-虽然已经建立了这种效应的一些系统学，但机制还没有。为了实现这一目标，他们将在细胞周期的不同时期将青蛙胚胎置于磁场中，以确定磁场的影响何时最强。他们将使用免疫细胞化学和共聚焦显微镜技术对暴露于磁场的胚胎微管的方向和形态进行成像，以确定磁场的影响。具体目标2：确定体内微管是否与磁场对齐-可能参与磁场重定向的细胞结构是由微管组成的。微管构成有丝分裂器的主要部分，并且最近的测量显示单个微管在体外磁场中排列。由于微管的重要性，卵裂面重定向效应和许多其他的细胞过程，第二个目标是成像的微管在磁场暴露的青蛙胚胎，以辨别它们是否倾向于与磁场方向对齐。免疫细胞化学和共聚焦显微镜技术将被用来成像的星形微管在现场暴露，非洲爪蟾胚胎和比较观察到的微管形状的计算使用已知的特性的微管。如果微管确实对齐，则存在其他微管依赖性细胞过程可以用磁场操纵的可能性。如果它们不这样做，那么生命系统中的微管具有与体外对应物不同的特性。研究这种差异的来源可以提供对体内过程的洞察。这些实验应该为磁场和物质之间的相互作用提供全新的见解，这些相互作用可能导致这些相互作用的一般规则以及“磁操纵”作为可行的研究工具的潜力。该项目由分子生物科学部细胞生物学计划共同支持，生物科学局（BIO）和数学和物理科学局（MPS）的多学科活动办公室（OMA）。

While many aspects of mitosis and cytokinesis have been elucidated, a vast amount of ongoing work focuses on these fundamental processes showing that much remains for discovery and resolution. Advances in microscopy and immunocytochemistry and techniques for the mechanical, optical and biochemical manipulation of cells and their components have traditionally led and continue to lead to substantial progress in this field. Valles and coworkers recently discovered that early cleavages (cell divisions) of embryos of the frog, Xenopus laevis, align with a large static magnetic field. The reorientation of cleavages depends systematically on field strength and orientation and does not depend on field gradients. This novel discovery presents opportunities for dissecting interactions between cells and magnetic fields and potentially developing a new tool for manipulating cells and studying cell division. The two specific objectives address these opportunities.Specific Objective 1: Determine the cleavage plane reorientation mechanism- While some systematics of this effect have been established, the mechanism has not. To achieve this goal, they will subject sets of frog embryos to magnetic fields during different periods of their cell cycle to identify when the influence of the magnetic field is strongest. They will use immunocytochemistry and confocal microscopy techniques to image the orientation and morphology of the microtubules of embryos exposed to the magnetic field to determine the influence of the magnetic field. Specific Objective 2: Determine whether microtubules in vivo align with a magnetic field -Cellular structures that are likely to be involved in the reorientation by magnetic field are those composed of microtubules. Microtubules comprise a major portion of the mitotic apparatus and recent measurements have shown that individual microtubules align in vitro in a magnetic field. Because of the importance of microtubules to the cleavage plane reorientation effect and to many other cell processes, the second goal is to image the microtubules in magnetic field exposed frog embryos to discern whether or not they are tending to align with the field direction. Immunocytochemistry and confocal microscopy techniques will be used to image the astral microtubules in field exposed, Xenopus embryos and compare the observed microtubule shapes to those calculated using the known properties of microtubules. If the microtubules do align then the possibility exists that other microtubule dependent cell processes can be manipulated with magnetic fields. If they do not, then the microtubules in living systems have properties that differ from their in vitro counterparts. Examining the source of such differences can provide insight into in vivo processes.Together, these experiments should provide fundamentally new insight into the interactions between magnetic fields and matter that might lead to general rules about those interactions and the potential for "magneto-manipulation" as a viable research tool.This project is jointly supported by the Cell Biology Program in the Division of Molecular Biosciences, Directorate for Biological Sciences (BIO) and the Office of Multidisciplinary Activities (OMA) in the Directorate for Mathematical and Physical Sciences (MPS).