The response of microbes to external signals is mediated by biochemical networks with intrinsic time scales. These time scales give rise to a memory that impacts cellular behaviour. Here we study theoretically the role of cellular memory in Escherichia coli chemotaxis. Using an agent-based model, we show that cells with memory navigating rugged chemoattractant landscapes can enhance their drift speed by extracting information from environmental correlations. Maximal advantage is achieved when the memory is comparable to the time scale of fluctuations as perceived during swimming. We derive an analytical approximation for the drift velocity in rugged landscapes that explains the enhanced velocity, and recovers standard Keller–Segel gradient-sensing results in the limits when memory and fluctuation time scales are well separated. Our numerics also show that cellular memory can induce bet-hedging at the population level resulting in long-lived, multi-modal distributions in heterogeneous landscapes.

微生物对外部信号的反应是由具有固有时间尺度的生化网络介导的。这些时间尺度会产生影响细胞行为的记忆。在这里，我们从理论上研究细胞记忆在大肠杆菌中的作用趋化性。使用基于代理的模型，我们表明具有记忆导航能力的崎che趋化景观的细胞可以通过从环境相关性中提取信息来提高其漂移速度。当记忆可与游泳时感觉到的波动的时间尺度相媲美时，可以实现最大的优势。我们得出了崎landscape景观中漂移速度的解析近似值，可以解释速度的提高，并且当记忆和波动时间尺度很好地分开时，可以在极限范围内恢复标准的Keller-Segel梯度传感结果。我们的数字还表明，细胞记忆可以在人口水平上引发对冲，导致异质景观中存在长寿命的多峰分布。