Single-cell imaging, combined with recent advances in image analysis and microfluidic technologies, have enabled fundamental discoveries of cellular responses to chemical perturbations that are often obscured by traditional liquid-culture experiments. Temperature is an environmental variable well known to impact growth and to elicit specific stress responses at extreme values; it is often used as a genetic tool to interrogate essential genes. However, the dynamic effects of temperature shifts have remained mostly unstudied at the single-cell level, due largely to engineering challenges related to sample stability, heatsink considerations, and temperature measurement and feedback. Additionally, the few commercially available temperature-control platforms are costly. Here, we report an inexpensive (<$110) and modular Single-Cell Temperature Controller (SiCTeC) device for microbial imaging, based on straightforward modifications of the typical slide-sample-coverslip approach to microbial imaging, that controls temperature using a ring-shaped Peltier module and microcontroller feedback. Through stable and precise (±0.15 °C) temperature control, SiCTeC achieves reproducible and fast (1-2 min) temperature transitions with programmable waveforms between room temperature and 45 °C with an air objective. At the device's maximum temperature of 89 °C, SiCTeC revealed that Escherichia coli cells progressively shrink and lose cellular contents. During oscillations between 30 °C and 37 °C, cells rapidly adapted their response to temperature upshifts. Furthermore, SiCTeC enabled the discovery of rapid morphological changes and enhanced sensitivity to substrate stiffness during upshifts to nonpermissive temperatures in temperature-sensitive mutants of cell-wall synthesis enzymes. Overall, the simplicity and affordability of SiCTeC empowers future studies of the temperature dependence of single-cell physiology.

中文翻译：

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SiCTeC：一种便宜，易于组装的Peltier器件，可在单细胞成像期间快速进行温度转换

单细胞成像与图像分析和微流体技术的最新进展相结合，已经实现了细胞对化学扰动反应的基础发现，而传统液体培养实验常常掩盖了这些化学扰动。温度是众所周知的环境变量，会影响生长并在极限值处引起特定的应力响应。它通常被用作询问基本基因的遗传工具。然而，由于与样品稳定性，散热片考虑因素以及温度测量和反馈有关的工程难题，在单电池水平上对温度变化的动态影响仍未得到充分研究。另外，很少有市售的温度控制平台价格昂贵。在这里，我们报告了便宜的价格（< 110美元）和用于微生物成像的模块化单细胞温度控制器（SiCTeC）设备，是对典型的幻灯片样本-盖玻片微生物成像方法的直接修改的基础，该方法使用环形Peltier模块和微控制器反馈来控制温度。通过稳定且精确的（±0.15°C）温度控制，SiCTeC可以在室温至45°C的温度范围内以空气目标通过可编程波形实现可再现且快速的（1-2分钟）温度转换。在设备的最高温度为89°C时，SiCTeC显示大肠杆菌细胞逐渐收缩并失去细胞内含物。在30°C和37°C之间的振荡期间，细胞迅速适应了温度升高的响应。此外，SiCTeC能够在细胞壁合成酶的温度敏感突变体向非容许温度上移的过程中发现快速的形态变化并增强对底物刚度的敏感性。总的来说，SiCTeC的简单性和可承受性使未来对单细胞生理温度依赖性的研究成为可能。