Spatial gradient sensing and chemotaxis via excitability in Dictyostelium discoideum.
Spatial gradient sensing and chemotaxis via excitability in Dictyostelium discoideum.
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DOI：
10.1103/physreve.101.062410
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发表时间：
2020-06
影响因子：
2.4
通讯作者：
Schwab, David J.
中科院分区：
文献类型：
--
作者：
Shams, Daniel P.;Yang, Xingbo;Mehta, Pankaj;Schwab, David J.
社会性阿米巴Dictyosteelicdiscoideum在饥饿条件下执行趋化性，在信号分子cAMP的波之后向细胞簇聚集。细胞感知细胞外cAMP并产生待释放的cAMP的内部缓存，传递信号。这些事件导致cAMP的行波冲刷细胞群。虽然已经进行了大量的研究来了解D. discoideum，已经做了有限的工作来将信号中继网络的操作与趋化性网络联系起来，以提供系统的整体视图。我们的灵感来自D。discoideum，并提出了一个模型，直接链接到该信号的定向传感的化学信息的中继。利用一个可激发的动力系统模型，已被实验验证，我们表明，这是可能的，在一个单一的模块中既有信号放大和完美的适应。我们发现，噪声在静态梯度的趋化中起着至关重要的作用，瞬态突发的随机隧穿使系统偏向于准确的梯度传感。此外，该模型还自动将其内部适应时间尺度与种群中产生的行进化学波的自然发生的周期性相匹配。数值模拟进行研究的定性现象学的系统，并探讨系统如何响应不同的动态时空刺激。最后，我们解决动态不稳定性，阻碍趋化能力的连续版本的模型。
The social amoeba Dictyostelium discoideum performs chemotaxis under starvation conditions, aggregating towards clusters of cells following waves of the signaling molecule cAMP. Cells sense extracellular cAMP and produce internal caches of cAMP to be released, relaying the signal. These events lead to traveling waves of cAMP washing over the population of cells. While much research has been performed to understand the functioning of the chemotaxis network in D. discoideum, limited work has been done to link the operation of the signal relay network with the chemotaxis network to provide a holistic view of the system. We take inspiration from D. discoideum and propose a model that directly links the relaying of a chemical message to the directional sensing of that signal. Utilizing an excitable dynamical systems model that has been previously validated experimentally, we show that it is possible to have both signal amplification and perfect adaptation in a single module. We show that noise plays a vital role in chemotaxing to static gradients, where stochastic tunneling of transient bursts biases the system towards accurate gradient sensing. Moreover, this model also automatically matches its internal time scale of adaptation to the naturally occurring periodicity of the traveling chemical waves generated in the population. Numerical simulations were performed to study the qualitative phenomenology of the system and explore how the system responds to diverse dynamic spatiotemporal stimuli. Finally, we address dynamical instabilities that impede chemotactic ability in a continuum version of the model.