F-pili dynamics by live-cell imaging
F-pili dynamics by live-cell imaging
复制标题
DOI：
10.1073/pnas.0806786105
复制
发表时间：
2008-11-18
影响因子：
11.1
通讯作者：
Silverman, Philip M.
中科院分区：
文献类型：
--
作者：
Clarke, Margaret;Maddera, Lucinda;Silverman, Philip M.
细菌已经进化出许多细胞间通讯的机制，其中许多对人类健康有重要影响。其中之一是接合，即DNA从一个细胞直接转移到另一个细胞。对于革兰氏阴性细菌，接合需要由DNA供体细胞精心制作的薄的柔性细丝（接合皮利）。结合性皮利的结构、功能，尤其是动力学尚不清楚。在这里，我们应用活细胞成像来表征F-皮利（大肠杆菌F质粒编码的接合皮利）的动态。我们确定，F-菌毛通常在没有任何明显的触发事件（如与受体细胞接触）的情况下经历伸展和收缩的周期。当形成时，这种接触能够经受住液体介质中细菌所感受到的剪切力。我们的数据强调了F-菌毛的灵活性在液体培养中有效地采样大量供体细胞周围以及建立和维持细胞-细胞接触中的作用。此外，出乎意料的是，我们推断，延伸和收缩伴随着围绕长轴的长丝旋转。
Bacteria have evolved numerous mechanisms for cell-cell communication, many of which have important consequences for human health. Among these is conjugation, the direct transfer of DNA from one cell to another. For Gram-negative bacteria, conjugation requires thin, flexible filaments (conjugative pili) that are elaborated by DNA donor cells. The structure, function, and especially the dynamics of conjugative pili are poorly understood. Here, we have applied live-cell imaging to characterize the dynamics of F-pili (conjugative pili encoded by the F plasmid of Escherichia coli). We establish that F-pili normally undergo cycles of extension and retraction in the absence of any obvious triggering event, such as contact with a recipient cell. When made, such contacts are able to survive the shear forces felt by bacteria in liquid media. Our data emphasize the role of F-pilus flexibility both in efficiently sampling a large volume surrounding donor cells in liquid culture and in establishing and maintaining cell-cell contact. Additionally and unexpectedly, we infer that extension and retraction are accompanied by rotation about the long axis of the filament.