Variation in swimming speed of Escherichia coli in response to attractant
Variation in swimming speed of Escherichia coli in response to attractant
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DOI：
10.1007/s00203-014-1044-5
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发表时间：
2015-03-01
影响因子：
2.8
通讯作者：
Venkatesh, K. V.
中科院分区：
文献类型：
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作者：
Deepika, Deepti;Karmakar, Richa;Venkatesh, K. V.
众所周知，大肠杆菌通过单独调节鞭毛运动偏向来响应化学线索，从而执行趋化运动。然而，先前的研究已经报道了在引诱剂存在的情况下运行速度变化的可能性，尽管尚不清楚细菌是否可以根据环境提示故意调节其游泳速度，或者是否马达速度是固定的。通过研究细胞在均匀浓度的葡萄糖及其非代谢类似物中的详细运动，我们表明浓度的变化可能伴随着游泳速度的变化。在固定的运行时间内，暴露于引诱剂的细胞在翻滚后的峰值游泳速度比在普通运动缓冲液中的细胞高。我们使用缺乏Trg传感器的突变菌株进行的实验显示，随着非代谢类似物浓度的变化，游泳速度没有变化，这表明感知可能在观察到的游泳速度变化中起作用。
It is well known that Escherichia coli executes chemotactic motion in response to chemical cues by modulating the flagellar motor bias alone. However, previous studies have reported the possibility of variation in run speed in the presence of attractants although it is unclear whether bacteria can deliberately modulate their swimming speeds in response to environmental cues or if the motor speeds are hardwired. By studying the detailed motion of cells in a uniform concentration of glucose and its non-metabolizable analogue, we show that changing concentrations may be accompanied by variation in the swimming speed. For a fixed run duration, cells exposed to the attractants achieved a higher peak-swimming speed after a tumble compared with that in plain motility buffer. Our experiments using the mutant strain lacking the Trg sensor show no change in swimming speed with varying concentrations of the non-metabolizable analogue, suggesting that sensing may play a role in the observed variation of swimming speed.