Investigation of the functions of microfilaments and microtubules by cytomagnetometry, immunoflurescent microscopy and differential interference microscopy.

我们通过细胞磁术和光学观察（包括免疫荧光显微镜和差示干涉显微镜）研究了活细胞的胞内运动。细胞磁仪是我们自己发明的方法，也是为数不多的能够研究活细胞内细胞运动和细胞骨架功能的方法之一。在本研究中，我们集中测量了吞噬体随机运动的细胞内运动的能量（E_r），吞噬体随机运动导致了被细胞吞噬的磁性粒子磁化后的磁松弛。采用影响微丝、微管等细胞骨架的细胞骨架药物，测定E_r，并用免疫荧光显微镜观察药物对微丝的影响。一个奇特的结果是抑制ATP合成的MIA增加了E_r，这似乎是矛盾的。MIA还抑制了微丝的合成，这可能与E_r的增加有关，尽管破坏微丝的细胞松弛素B降低了E_r。已知能破坏微管的秋水仙碱也增加了E_r。这可能是由于其激活细胞运动的副作用（其他研究人员已经观察到这一点）和免疫荧光显微镜清楚地看到的微丝增加。因此，我们对E_r的测量定量地捕捉到了这一现象。细胞磁术的另一种应用是测量细胞膜的硬度。这是通过使涂有纤维连接蛋白的磁性颗粒附着在细胞膜上，并通过外部磁场扭曲它们来实现的。该方法初步应用于研究细胞骨架与细胞膜之间的关系，有望测量细胞膜的力学性能及其对细胞骨架的依赖性。

We investigated intracellular motility of living cells by cytomagnetometry and optical observations including immunoflurescent microscopy and differential interference microscopy. Cytomagnetometric method is our own invention and one of few methods able to investigate intracellular movement and the functions of the cytoskeletons within living cells. In the present study we concentrated on the measurement of the energy (E_r) of the intracellular movements responsible for the random movements of the phagosomes which causes the magnetic relaxation measured after magnetizing the magnetic particles engulfed by the cells. We used cytoskeletal drugs which affect the cytoskeletons such as microfilaments and microtubules, and measured E_r and observed the effects of those drugs on the filaments by immunoflurescent microscopy. One peculiar result was that MIA which inhibits ATP synthesis increased E_r which seems contradictory. MIA also inhibited microfilament synthesis, which may have to do with the increase in E_r although cytochalasin B which disrupts microfilaments decreased E_r. Colchicine, which has been known to break microtubules increased E_r also. This is probably due to its side effect of activation of cellular movements (which has been observed by other researchers) and of increasing microfilaments which has been clearly seen by immunoflurescent microscopy. Our measurement of E_r thus captured the phenomenon quantitatively. A different application of cytomagnetometry is measurement of the stiffness of the cell membrane. This was done by making magnetic particles coated with fibronectin adhere to the cell membrane and twisting them by an external magnetic field. This method was tentatively applied to investigate the relationship between the cytoskeletons and the cell membrane and seems promising to measure the mechanical properties of the cell membrane and their dependence on the cytoskeletons.