Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, Maryland, USA.
Biophys J. 2011 Jul 20;101(2):327-35. doi: 10.1016/j.bpj.2011.06.005.
In bacteria, cytoskeletal filament bundles such as MreB control the cell morphology and determine whether the cell takes on a spherical or a rod-like shape. Here we use a theoretical model to describe the interplay of cell wall growth, mechanics, and cytoskeletal filaments in shaping the bacterial cell. We predict that growing cells without MreB exhibit an instability that favors rounded cells. MreB can mechanically reinforce the cell wall and prevent the onset of instability. We propose that the overall bacterial shape is determined by a dynamic turnover of cell wall material that is controlled by mechanical stresses in the wall. The model affirms that morphological transformations with and without MreB are reversible, and quantitatively describes the growth of irregular shapes and cells undergoing division. The theory also suggests a unique coupling between mechanics and chemistry that can control organismal shapes in general.
在细菌中，细胞骨架丝束（如 MreB）控制着细胞形态，决定着细胞是呈球形还是杆状。在这里，我们使用一个理论模型来描述细胞壁生长、力学和细胞骨架丝在塑造细菌细胞中的相互作用。我们预测，没有 MreB 的生长细胞会表现出有利于圆形细胞的不稳定性。MreB 可以机械地增强细胞壁并防止不稳定性的发生。我们提出，细菌的整体形状是由细胞壁材料的动态周转决定的，这种周转受细胞壁中的机械应力控制。该模型证实了有和没有 MreB 的形态转化都是可逆的，并定量描述了不规则形状的生长和正在进行分裂的细胞。该理论还表明，力学和化学之间存在一种独特的耦合，这种耦合可以控制一般的生物体形状。
