应变速率调控生长中细菌单层膜的排列
Strain rate controls alignment in growing bacterial monolayers
AI总结：
针对细菌单层膜全局排列机制不明的问题，提出基于应变的模型，可关联单层净形变与细胞级形变，能在多种几何限制下正确预测排列方向并定量预测取向序，填补了相关研究空白。
摘要：
生长中的杆状细菌单层膜表现出类似于可拉伸活性向列相的局部排列特性。当被限制在通道中或从环形结构向内生长时，这些单层膜的局部向列序会转变为全局有序，整个单层膜内的细胞都沿同一方向取向。目前这一现象背后的机制尚不明确，因为此前提出的机制都无法在一种或多种限制几何结构中预测出正确的排列方向。我们提出了一个基于应变的模型，将生长中单层膜的净形变与单细胞生长和旋转导致的细胞层面形变关联起来，可基于单层膜内的速度场预测细胞取向行为。该模型能正确预测通道限制、向内生长以及无限制菌落中的优先排列方向。当速度场在任何方向上都不存在净负应变速率时，该模型还能定量预测取向序。我们进一步在限制于球面的扩张菌落模拟中测试了我们的模型。我们的模型与模拟结果一致表明，远离起始细胞的细胞相对于菌落中心呈径向取向。此外，我们的模型对取向序的定量预测在球面上半部分与模拟结果相符，但在存在净负应变速率的下半部分则不相符。我们模型的成功填补了此前不同限制几何结构下细胞排列相关研究之间的空白，并为导致大规模排列的潜在物理效应提供了见解。
英文摘要：
Growing monolayers of rod-shaped bacteria exhibit local alignment similar to extensile active nematics. When confined in a channel or growing inward from a ring, the local nematic order of these monolayers changes to a global ordering with cells throughout the monolayer orienting in the same direction. The mechanism behind this phenomenon is so far unclear, as previously proposed mechanisms fail to predict the correct alignment direction in one or more confinement geometries. We present a strain-based model relating net deformation of the growing monolayer to the cell-level deformation resulting from single-cell growth and rotation, producing predictions of cell orientation behavior based on the velocity field in the monolayer. This model correctly predicts the direction of preferential alignment in channel-confined, inward-growing, and unconfined colonies. The model also quantitatively predicts orientational order when the velocity field has no net negative strain rate in any direction. We further test our model in simulations of expanding colonies confined to spherical surfaces. Our model and simulations agree that cells away from the origin cell orient radially relative to the colony's center. Additionally, our model's quantitative prediction of the orientational order agrees with the simulation results in the top half of the sphere but fails in the lower half where there is a net negative strain rate. The success of our model bridges the gap between previous works on cell alignment in disparate confinement geometries and provides insight into the underlying physical effects responsible for large-scale alignment.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
