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

趋化性是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健康的许多过程有关：炎症，神经元模式，伤口愈合，癌症中的肿瘤扩散，甚至胚胎发生。据推测，控制趋化性的基本方面的分子机制似乎是进化保守的。[2]由于这个原因，在低等真核生物模型中的研究极大地帮助理解了工作原理，揭示了分子引诱剂和信号物质，并测试了各种趋化模型和策略。最近开发的一种装置允许研究导致简单人工活性物质中趋化的物理原理[3]，揭示了这种现象背后的泳动原理。这些原则如何影响早期细菌，使一些轻微的进化优势可能为最简单的检测原则的发展铺平了道路，很少成为研究的焦点。现在，我们的目标是通过研究运动细菌及其孢子在化学梯度中的行为来关闭循环。

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.