Mechanical properties of bacterial hook filament

细菌钩丝的力学性能

基本信息

批准号：
17340126
负责人：
YOSHIMURA Hideyuki
金额：
$ 10.55万
依托单位：
Meiji University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17340126/
关键词：
flagella polyhook Young's modulus rigidity fluorescence electronmicroscopy rapid freezing freeze dry レーザトラップ

项目摘要

Flagellated bacteria like Sal. Typhimurium swims by rotating helical flagella filaments with bundling and synchronizing them each other. Because axs of bacterial motors directed in different way, flexible joint part is required between motor and flagella filament. It is known that bacterial hook work as a universal joint of this part. However its mechanical feature like rigidity is not known exactly. Here we measured modulus of rigidity by using polyhook filament, length about 1μm, from mutant Sal. Typhimurium(SWJ108). Purified polyhook filaments were frozen rapidly in liquid ethane and freeze dried. Distribution of helix pitch and diameter were evaluated from electron micrographs of shadowed images. We got value of 95±23nm for helix pitch and 31±9.9nm for diameter of polyhook filament. We also measured fluctuation of helical pitch and diameter of flagella filament from negative stained samples. By comparing fluctuation of polyhook and flagella filaments, we have calculated the ratio of rigidity as G_<flagella>/G<hook>=120. According to the literature value of flagella filament rigidity, 3.8×10^9Pa, we obtained rigidity of polyhook as 3.3×10^7Pa. We also tried to measure the rigidity of flagella in solution directly using thin glass capillary. Fluorescent labeled flagella filament was fixed by anti-flagellin adsorbed on a glass capillary of diameter less than 1μm. Tension in pN range was measured from bending deformation of glass capillary under fluorescent microscope. We are now accumulating the results in this process. We are going to measure rigidity of super-poly hook which has length of few micro-meter by the same method.

像sal一样，f细菌以不同的方式定向，但它的机械特征是固定的在液体乙烷中迅速冷冻，冻干的质量为95，对于polyhook的直径，我们还测量了螺旋螺旋杆的波动鞭毛丝ty作为g_ <鞭毛>/g <hook> = 120。根据鞭毛细丝的文献值，3.8×10^ 9pa，我们获得了polyhook的刚性为3.3×10^ 7pa。在使用薄玻璃Y的溶液中，抗鞭毛蛋白在玻璃直径小于1μm的玻璃毛细管上固定通过相同的方法测量极少数微米的超极长长度的严格性。