简介：
Bacteria Could Be Living Structural Sensors
细菌传感器
A soil bacterium changes its growth pattern in response to disturbances in its environment, making it a candidate to be a living system for sensing strain in materials under heavy loads. Cynthia Graber reports
一种生存在土壤中的细菌，能够根据环境的变化调整自己的生长模式，这种特殊的能力，使材料学家把它们当做了一种“应力传感器”。
撰文/播音 辛西娅•格雷伯（Cynthia Graber）
翻译 李轩
Cells in complex organisms sometimes respond to pressure and stress by growing in a preferred direction. The phenomenon, called mechanotaxis, helps create multicellular structures such as our organs.
有时候，复杂生命体内的细胞为了应对物理压力变化，会改变自己的生长方向。这种现象被称为机械趋性，它能帮助机体形成多细胞结构，比如我们的器官。
Now a common soil bacterium has been found to change its growth pattern in response to disturbances in its environment. And the discovery could provide a living system for testing strain in materials under heavy loads—like, say, bridges.
研究人员发现了一种普通的土壤细菌，它们能因为生长环境的变化而改变自己的生长模式。这一发现可以为我们提供一种生物传感系统，检测材料（比如桥梁）在荷重时的应力。
The bacterium in question is called Bacillus mycoides. It was first characterized way back in 1842. Much more recently, researchers in the U.K. noticed that the Bacillus had unique growth patterns on solid cultures that contained structural defects.
该细菌名叫枯草芽孢杆菌（Bacillus mycoides）。人们早在1842年就发现了这种细菌，而最近，英国的研究人员注意到，枯草芽孢杆菌在有结构缺陷的固体培养基上，具有特殊的生长模式。
The scientists took a series of microscope photos of bacterial cultures on templates with a variety of defects and under different pressures. And the bacterial filaments turned a full 90 degrees in response to only 1 degree of structural distortion. The bacteria also grew towards a glass bead disturbing the culture. The research is in the journal PLoS One. [James P. Stratford, Michael A. Woodley and Simon Park, Variation in the Morphology of Bacillus mycoides Due to Applied Force and Substrate Structure]
科学家为生长在培养皿的这些细菌拍摄了一系列显微照片，培养皿中的培养基都因受到不同的物理压力而呈现出一些结构上的缺陷。他们发现，培养基仅发生1°的变形，的就会使细菌的鞭毛转动90°。而且，细菌还会朝着破坏培养基结构的玻璃珠生长。该研究结果发表在了《公共科学图书馆•综合》（PLoS One）上。
If this technique can be better understood and manipulated, scientists might be able to develop a bacterial early warning system for our engineered environment. A big help from a small creature.
如果科学家可以充分理解和控制这一过程，或许就能开发出一套服务于工程学的细菌预警系统。细菌虽小，用处却大。
(题图来源：Gracias Laboratory, Johns Hopkins University)
