Essington Erin A, Vezeau Grace E, Cetnar Daniel P, Grandinette Emily, Bell Terrence H, Salis Howard M
Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA.
Department of Biological Engineering, The Pennsylvania State University, University Park, PA, USA.
Nat Commun. 2024 Dec 2;15(1):10471. doi: 10.1038/s41467-024-54866-y.
Microbes can be engineered to sense target chemicals for environmental and geospatial detection. However, when engineered microbes operate in real-world environments, it remains unclear how competition with natural microbes affect their performance over long time periods. Here, we engineer sensors and memory-storing genetic circuits inside the soil bacterium Bacillus subtilis to sense the TNT explosive and maintain a long-term response, using predictive models to design riboswitch sensors, tune transcription rates, and improve the genetic circuit's dynamic range. We characterize the autonomous microbial sensor's ability to detect TNT in a natural soil system, measuring single-cell and population-level behavior over a 28-day period. The autonomous microbial sensor activates its response by 14-fold when exposed to low TNT concentrations and maintains stable activation for over 21 days, exhibiting exponential decay dynamics at the population-level with a half-life of about 5 days. Overall, we show that autonomous microbial sensors can carry out long-term detection of an important chemical in natural soil with competitive growth dynamics serving as additional biocontainment.
微生物可经过改造以感知目标化学物质，用于环境和地理空间检测。然而，当工程微生物在现实环境中运行时，与天然微生物的竞争如何在长时间内影响其性能仍不清楚。在此，我们在土壤细菌枯草芽孢杆菌内构建传感器和存储记忆的遗传电路，以感知三硝基甲苯（TNT）炸药并维持长期响应，利用预测模型设计核糖开关传感器、调整转录速率并提高遗传电路的动态范围。我们表征了自主微生物传感器在天然土壤系统中检测TNT的能力，在28天内测量单细胞和群体水平的行为。当暴露于低TNT浓度时，自主微生物传感器的响应激活了14倍，并在超过21天的时间内保持稳定激活，在群体水平上呈现指数衰减动态，半衰期约为5天。总体而言，我们表明自主微生物传感器可以在天然土壤中对一种重要化学物质进行长期检测，竞争性生长动态可作为额外的生物防护。
