Bacterial Chemotaxis in an Optical Trap
Bacterial Chemotaxis in an Optical Trap
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DOI：
10.1371/journal.pone.0018231
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发表时间：
2011-04-08
期刊：
影响因子：
3.7
通讯作者：
Wu, Xiao-Lun
中科院分区：
文献类型：
--
作者：
Altindal, Tuba;Chattopadhyay, Suddhashil;Wu, Xiao-Lun
采用光捕获技术研究了一株海洋细菌溶藻弧菌的趋化行为。该技术利用了细菌只有一个极鞭毛的优势，它可以逆时针或顺时针方向旋转。马达的两种旋转状态可以在光阱中容易地和瞬时地分辨，从而允许在不同的化学刺激下测量鞭毛马达切换速率S（t）。在本文中，重点将是细菌的化学引诱丝氨酸的脉冲变化的反应。尽管有不同的推进装置和运动模式，溶藻弧菌的细胞显然使用与大肠杆菌相似的反应来调节其趋化行为。具体而言，我们发现细菌马达的开关速率S（t）表现出双相行为，显示出快速的初始响应，随后缓慢松弛至稳态开关速率S（0）。测量的S（t）可以通过最近提出的E.杆菌这两种不同细菌对短暂化学刺激的反应具有惊人的相似性，这表明双相反应可能在进化上是保守的。这项研究也表明，光镊可以是一个有用的工具，趋化性的研究，并应适用于其他极性鞭毛细菌。
An optical trapping technique is implemented to investigate the chemotactic behavior of a marine bacterial strain Vibrio alginolyticus. The technique takes the advantage that the bacterium has only a single polar flagellum, which can rotate either in the counter-clock-wise or clock-wise direction. The two rotation states of the motor can be readily and instantaneously resolved in the optical trap, allowing the flagellar motor switching rate S(t) to be measured under different chemical stimulations. In this paper the focus will be on the bacterial response to an impulsive change of chemoattractant serine. Despite different propulsion apparati and motility patterns, cells of V. alginolyticus apparently use a similar response as Escherichia coli to regulate their chemotactic behavior. Specifically, we found that the switching rate S(t) of the bacterial motor exhibits a biphasic behavior, showing a fast initial response followed by a slow relaxation to the steady-state switching rate S(0). The measured S(t) can be mimicked by a model that has been recently proposed for chemotaxis in E. coli. The similarity in the response to the brief chemical stimulation in these two different bacteria is striking, suggesting that the biphasic response may be evolutionarily conserved. This study also demonstrated that optical tweezers can be a useful tool for chemotaxis studies and should be applicable to other polarly flagellated bacteria.