Environmental structure describes physical structure that can determine heterogenous spatial distribution of biotic and abiotic (nutrients, stressors etc.) components of a microorganism’s microenvironment. This study investigated the impact of micrometre-scale structure on microbial stress sensing, using yeast cells exposed to copper in microfluidic devices comprising either complex soil-like architectures or simplified environmental structures. In the soil micromodels, the responses of individual cells to inflowing medium supplemented with high copper (using cells expressing a copper-responsive pCUP1-reporter fusion) could be described neither by spatial metrics developed to quantify proximity to environmental structures and surrounding space, nor by computational modelling of fluid flow in the systems. In contrast, the proximities of cells to structures did correlate with their responses to elevated copper in microfluidic chambers that contained simplified environmental structure. Here, cells within more open spaces showed the stronger responses to the copper-supplemented inflow. These insights highlight not only the importance of structure for microbial responses to their chemical environment, but also how predictive modelling of these interactions can depend on complexity of the system, even when deploying controlled laboratory conditions and microfluidics.

环境结构描述了物理结构，可以确定微生物微环境的生物和非生物（营养物、压力源等）成分的异质空间分布。本研究使用暴露于铜的酵母细胞在微流体装置中研究微米级结构对微生物压力传感的影响，该微流体装置包括复杂的类土壤结构或简化的环境结构。在土壤微模型中，单个细胞对补充高铜的流入培养基的反应（使用表达铜响应pCUP1 的细胞）-reporter fusion) 既不能通过为量化与环境结构和周围空间的接近度而开发的空间度量来描述，也不能通过系统中流体流动的计算模型来描述。相比之下，细胞与结构的接近程度确实与它们对包含简化环境结构的微流体室中铜升高的反应相关。在这里，更多开放空间内的细胞对补充铜的流入表现出更强的反应。这些见解不仅突出了微生物对其化学环境反应的结构的重要性，而且突出了这些相互作用的预测建模如何取决于系统的复杂性，即使在部署受控实验室条件和微流体时也是如此。