Abstract：
Amoeboid cells such as the protist Dictyostelium, human neutrophils, and the fungus B.d. chytrid move by extending pseudopods. The trajectories of cell movement depend on the size, rhythm, and direction of long series of pseudopods. These pseudopod properties are regulated by internal factors such as memory of previous directions and by external factors such as gradients of chemoattractants or electric currents. Here a simple method is described that defines the X, Y time coordinates of a pseudopod at the start and the end of the extension phase. The connection between the start and end of an extending pseudopod defines a vector, which is the input of different levels of analysis that defines cell movement. The primary information of the vector is its spatial length (pseudopod size), temporal length (extension time), extension rate (size divided by time), and direction. The second layer of information describes the sequence of two (or more) pseudopods: the direction of the second pseudopod relative to the direction of the first pseudopod, the start of the second pseudopod relative to the extension phase of the first pseudopod (the second starts while the first is still extending or after the first has stopped), and the alternating right/left extension of pseudopods. The third layer of information is provided by specific and detailed statistical analysis of these data and addresses question such as: is pseudopod extension in buffer in random direction or has the system internal directional memory, and how do shallow external electrical or chemical gradients bias the intrinsic pseudopod extension. The method is described for Dictyostelium, but has been used successfully for fast-moving neutrophils, slow-moving stem cells, and the fungus B.d. chytrid.
摘要：
变形虫细胞，如原生网藻，人类中性粒细胞，真菌B.d.通过延伸伪足而移动。细胞运动的轨迹取决于大小，节奏,和长系列伪足的方向。这些伪足类的特性受内部因素（例如对先前方向的记忆）和外部因素（例如化学引诱物或电流的梯度）的调节。这里描述了一个简单的方法，它定义了X，在扩展阶段的开始和结束时，伪pod的Y时间坐标。扩展伪足的开始和结束之间的连接定义了一个向量，它是定义细胞运动的不同分析级别的输入。向量的主要信息是它的空间长度（伪足大小），时间长度（延长时间），扩展速率(大小除以时间)，和方向。第二层信息描述了两个（或多个）伪足的序列：第二个伪足相对于第一个伪足的方向，第二伪足相对于第一伪足的延伸阶段的开始(第二在第一伪足仍在延伸时或在第一伪足已停止之后开始),以及伪足的交替右/左延伸。第三层信息通过对这些数据的具体和详细的统计分析提供，并解决诸如以下问题：是伪POD扩展在缓冲区中的随机方向或具有系统内部定向存储器，以及浅外部电或化学梯度如何偏置固有的伪足扩展。该方法被描述为网藻，但已成功用于快速移动的中性粒细胞，缓慢移动的干细胞，和真菌B.D.chytrid。
