Flow-driven waves, Phase-Locked patterns and Arnold-tongues during aggregation of Dictyostelium discoideum

细胞纤细霉菌Dictyostelialdiscoideum(D.D.)是研究生物格局形成和发展的有价值的模式生物。当缺乏营养时，D.D.细胞通过趋化cAMP的趋化反应聚集在一起，然后发育成多细胞子实体。这些细胞通过自发释放cAMP脉冲来启动这一过程。其他细胞对引诱剂刺激的反应是向其来源移动并传递信号。结果，圆形和螺旋波图案随时间形成，其周期为几分钟。在自然环境中，这种聚集发生在森林土壤中，可能会受到水流的影响。我们早期在一群信号D.D.中的流驱动波上所做的工作。细胞已经证明，外部流动可以显著改变波浪的产生过程。在本项目的实验部分，我们旨在研究流动驱动波对细胞迁移和D.D.聚集模式的影响。细胞。我们试图回答的一些问题如下：1)水流对D.D.时空格局的形成和细胞迁移有什么影响？细胞？2)在细胞信号的早期阶段，流动驱动波的存在如何影响D.D.的聚集模式。3)水流对这些生物在森林土壤中的生态有什么重要作用吗？此外，我们计划系统地研究在cAMP外部脉冲存在的情况下的自组织流动驱动波，以探索系统响应锁定在外部cAMP注入频率的参数区域。在受迫振荡系统中，显示锁相响应区域的映射称为阿诺德舌图。这将是探索在饥饿下经历发育途径的生命系统的完整阿诺德舌图的第一次努力。在平行的理论工作中，我们想要将我们的Martel-Goldbeter模型的二维模拟推广到三维，并研究cAMP在三维中的扩散对流动驱动波的作用。我们的目标还包括在模拟中包括趋化细胞运动，以研究在流动驱动波存在时细胞群体的分布。此外，我们还将进行大量的数值模拟，以找出阿诺图不同区域之间的过渡线，并将结果与实验结果进行比较。

The cellular slim mold Dictyostelium discoideum (D.d.) is a valuable model organism to study pattern formation and development in biology. When deprived of nutrients, D.d. cells aggregate by a chemotactic response to the chemoattractant cAMP and then develop to form multicellular fruiting bodies. The cells initiate the process by the spontaneous release of cAMP pulses. The other cells respond to the attractant stimulation by moving towards its source and by relaying the signal. As a result, circular and spiral wave patterns form with time which have a periodicity of few minutes. In the natural environment, this aggregation occurs in forest soil and may be subject to water flow. Our earlier work on flow-driven waves in a colony of signaling D.d. cells has shown that the external flow can significantly change the wave generation processes. In the experimental part of this project, we aim to investigate the effect of flow-driven waves on cell migration and the aggregation pattern of D.d. cells. Some of the questions we seek to answer are as follows: 1) What are the effects of water flow on the spatiotemporal pattern formation and cell migration of D.d. cells? 2) How does the presence of flow-driven waves in early stages of cell signaling influence the aggregation pattern of D.d. cells in later times? 3) Does flow play any significant role on the ecology of these organisms in the forest soil? Furthermore, we plan to systematically study self-organized flow-driven waves in the presence of external pulses of cAMP to explore the regions of parameters where the system response is locked to the injection frequency of external cAMP. In forced oscillatory systems, the map exhibiting regions of phase-locked responses is called Arnold tongues diagram. This would be the first effort to explore the complete Arnold tongues diagram for a living system that undergoes a developmental pathway under starvation. In the parallel theoretical work, we would like to extend our two-dimensional simu- lations of Martiel-Goldbeter model to three dimensions and investigate the role of diffusion of cAMP in three dimensions on flow-driven waves. We also aim to include chemotactic cell movement in the simulations to study the distribution of cell population in the presence of flow-driven waves. Furthermore, we will perform extensive numerical simulations to find the transition lines between different regions of the Arnold diagram and compare the results with the experimental findings.