To tax or not to tax? Parallels between chemotaxis and phoretic responses of bacterial spores

趋化性是指细胞的运动方向由一种或多种化学物质的梯度决定的现象。[1]了解趋化性与控制我们的健康的许多过程有关：炎症、神经元构型、伤口愈合、肿瘤在癌症中的扩散，甚至胚胎发育。人们假设控制趋化的基本方面的分子机制似乎在进化上是保守的。[2]因此，在低等真核模型中的研究极大地帮助理解了工作原理，发现了分子引诱剂和信号物质，并测试了各种趋化模型和策略。最近发展的一个装置允许研究在简单的人工活性物质中导致趋化的物理原理[3]，揭示了这种现象背后的显性原理。这些原理可能如何影响早期细菌，给了一些轻微的进化优势，这可能为大多数简单检测原理的发展铺平道路，但很少有研究的重点。现在，我们的目标是通过研究游动细菌及其孢子在化学梯度中的行为来结束这一循环。

Chemotaxis is the phenomenon that a cell's locomotion direction is determined by a gradient of one or more chemicals.[1] Understanding chemotaxis is relevant for many processes that control our well-being: inflammation, neuronal patterning, wound healing, tumor dissemination in cancer, and even embryogenesis. It is assumed that the molecular mechanisms that control fundamental aspects of chemotaxis appear to be evolutionarily conserved.[2] For this reason studies in lower eukaryotic models have helped massively to understand working principles, uncover molecular attractants and signalling substances and test a variety of chemotactic models and strategies.A recently developed setup allows the study of physical principles that lead to chemotaxis in simple artificial active matter[3] revealing phoretic principles that underly this phenomenon. How these principles might have affected early bacteria, giving some a slight evolutionary advantage which could have paved the way towards the development of most simple detection principles, has been rarely in the focus of research. Now, we aim at closing the loop by studying the behaviour of both, motile bacteria and their spores[4] in chemical gradients.