CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
National Institute of Standards and Technology (NIST), 100 Bureau Dr, Gaithersburg, Maryland, United States of America.
PLoS Comput Biol. 2024 May 14;20(5):e1012063. doi: 10.1371/journal.pcbi.1012063. eCollection 2024 May.
In this work, we quantitatively compare computer simulations and existing cell tracking data of P. aeruginosa surface motility in order to analyse the underlying motility mechanism. We present a three dimensional twitching motility model, that simulates the extension, retraction and surface association of individual Type IV Pili (TFP), and is informed by recent experimental observations of TFP. Sensitivity analysis is implemented to minimise the number of model parameters, and quantitative estimates for the remaining parameters are inferred from tracking data by approximate Bayesian computation. We argue that the motility mechanism is highly sensitive to experimental conditions. We predict a TFP retraction speed for the tracking data we study that is in a good agreement with experimental results obtained under very similar conditions. Furthermore, we examine whether estimates for biologically important parameters, whose direct experimental determination is challenging, can be inferred directly from tracking data. One example is the width of the distribution of TFP on the bacteria body. We predict that the TFP are broadly distributed over the bacteria pole in both walking and crawling motility types. Moreover, we identified specific configurations of TFP that lead to transitions between walking and crawling states.
在这项工作中，我们定量比较了铜绿假单胞菌表面迁移的计算机模拟和现有细胞跟踪数据，以分析潜在的迁移机制。我们提出了一个三维抽搐运动模型，模拟了单个 IV 型菌毛（TFP）的延伸、缩回和表面附着，并参考了最近关于 TFP 的实验观察。我们实施了敏感性分析以最小化模型参数的数量，并通过近似贝叶斯计算从跟踪数据中推断出剩余参数的定量估计。我们认为迁移机制对实验条件非常敏感。我们预测了我们研究的跟踪数据的 TFP 缩回速度，与在非常相似条件下获得的实验结果非常吻合。此外，我们还检查了是否可以直接从跟踪数据推断出直接进行实验测定具有挑战性的生物重要参数的估计值。一个例子是 TFP 在细菌体上的分布宽度。我们预测，在行走和爬行运动类型中，TFP 广泛分布在细菌的杆状部分。此外，我们确定了导致行走和爬行状态之间转换的特定 TFP 配置。
