Investigation of interactions between the organelle motion and filamentous structures within cells by cytomatomagnetometry.

我们研究了测压方法研究细胞内运动的可行性和有效性，特别是吞噬体膜和细胞内丝状结构之间可能的相互作用。目前的研究表明，这种方法可以作为研究吞噬小体运动基本过程的一个很好的探索者。我们称之为细胞磁测定法，它有以下优点。1)可以测量活细胞内的细胞内运动；2)测量本身相对容易；3)磁性粒子可以非侵入性地被外力操纵，因此可以进行各种实验；4)一次对大量细胞进行测量，得到足够的平均值。现在已经很清楚，细胞计量学产生的数据可以反映吞噬小体在细胞内的运动，通过操纵细胞内的磁性粒子可以获得也反映流变性的数据。我们的实验集中在吞噬体膜上的放线丝和肌球蛋白相互作用的吞噬小体运动的假说上。结果表明，肌动蛋白细丝确实在吞噬运动中起到了一定的作用，尽管结果并不像我们所希望的那样明确和决定性。观察肌动蛋白细丝产生粘性的实验产生了有趣但有趣的结果，进一步表明肌动蛋白参与了吞噬小体的运动。我们还建立了一个数学模型，其中吞噬小体膜上的肌球蛋白与包围吞噬小体的肌动蛋白细丝结合，并由ATP水解引起其分解。假设缔合和分解是泊松过程，结果表明，缔合和分解导致了旋转的随机游动，并且缔合对外力起到了摩擦的作用。

We studied the feasibility and efficacy of a mangetometric method for investigations of intracellular motions, particularly the possible interactions between phagosome membrane and filamentous strucures within the cell. The present investigation has focued on showing that this method can be a good probe in investiating the elementary processes in phagosome motions. Cytomagnetometry, as we call it, has the following advantages. 1)Intracellular motions within living cells can be measured ; 2)Measurement itself is relatively easy ; 3)Magnetic particles can be manipulated by an external force non-invasively and thus can be subject to a large variety of experiments ; 4)The measurement is done on a large number of cells at a time, resulting in enough averaging.It has now become clear that cytomagnetometry yields data which reflect intracellular motions of phagosomes and by manipulating the magnetic particles within cells one can obtain data which also reflect the rheological properties.Our experiments focused upon the hypothesis of phagosome motion through interaction of actinfilaments and myosin on the phagosome membrane. The results show that actin filaments do play some role in phagosme motion, although the results were not as clear cut and decisive as we had hoped. Experiments performed to see viscocity generation by actin filaments yielded intriguing but interesting results which further suggest actin's involvement in phagosome motions.We also built a mathematical model in which phagosome motions are caused by association of myosin on the phagosome membrane with an actin filament surrounding the phagosome and its decomposition caused by ATP hydrolysis. Association and decomposition were assumed to be Poisson processes and it was shown that it caused a rotationary random walk and also that the association acts as friction to external forces.