Institute of Environmental Engineering, ETH Zürich, Zürich, Switzerland.
Microbiology Graduate Program, Massachusetts Institute of Technology, Cambridge, MA, USA.
Nat Commun. 2021 Jun 16;12(1):3662. doi: 10.1038/s41467-021-23439-8.
It has long been known that bacteria coordinate their physiology with their nutrient environment, yet our current understanding offers little intuition for how bacteria respond to the second-to-minute scale fluctuations in nutrient concentration characteristic of many microbial habitats. To investigate the effects of rapid nutrient fluctuations on bacterial growth, we couple custom microfluidics with single-cell microscopy to quantify the growth rate of E. coli experiencing 30 s to 60 min nutrient fluctuations. Compared to steady environments of equal average concentration, fluctuating environments reduce growth rate by up to 50%. However, measured reductions in growth rate are only 38% of the growth loss predicted from single nutrient shifts. This enhancement derives from the distinct growth response of cells grown in environments that fluctuate rather than shift once. We report an unexpected physiology adapted for growth in nutrient fluctuations and implicate nutrient timescale as a critical environmental parameter beyond nutrient identity and concentration.
长期以来，人们一直知道细菌会根据其营养环境来协调其生理机能，但我们目前的理解几乎无法直观地了解细菌如何应对许多微生物栖息地中特征为秒到分钟级别的营养浓度波动。为了研究快速营养波动对细菌生长的影响，我们将定制的微流控技术与单细胞显微镜相结合，定量测量经历 30 秒至 60 分钟营养波动的大肠杆菌的生长速率。与具有同等平均浓度的稳定环境相比，波动环境会使生长速率降低多达 50%。然而，从单一营养物变化预测的生长速率降低仅为 38%。这种增强源自于在波动而非一次变化的环境中生长的细胞的不同生长反应。我们报告了一种适应于营养波动生长的意外生理学，并暗示营养时标是除营养物身份和浓度之外的一个关键环境参数。
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