Switching and Torque Generation in Swarming E. coli.
Switching and Torque Generation in Swarming E. coli.
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大肠杆菌群中的切换和转矩生成
DOI：
10.3389/fmicb.2018.02197
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发表时间：
2018
影响因子：
5.2
通讯作者：
Lele PP
中科院分区：
文献类型：
--
作者：
Ford KM;Antani JD;Nagarajan A;Johnson MM;Lele PP
大肠杆菌借助鞭毛在半固体表面上聚集。据推测，蜂群细胞克服了增加的粘性阻力附近的表面，通过开发更高的鞭毛推力和促进表面湿润的帮助下，鞭毛开关。开关使鞭毛马达的顺时针（CW）和逆时针（CCW）旋转方向之间的逆转。在这里，我们测量了鞭毛马达在蜂群细胞中的行为。结果表明，虽然扭矩是类似的，在反张细胞，逆时针旋转的倾向是更高的群集细胞。这表明蜂群可能具有较小的磷酸化CheY池。结果进一步表明，鞭毛蛋白基因的上调是不是至关重要的鞭毛推力或群集。与早期的报告一致，水分添加到蜂群表面恢复群集在一个CCW的突变体，但不是在一个FliG突变，旋转电机CW的唯一（FliGCW）。荧光分析显示，生长在琼脂表面上的FliGCW细胞携带较少的鞭毛比无菌FliGCW细胞。鞭毛的表面依赖性减少与推定的鞭毛预组装的数量减少。这些结果暗示了开关蛋白的构象动力学在鞭毛复合物和鞭毛出口的正确组装中发挥作用的可能性，从而有助于细菌群集。
Escherichia coli swarm on semi-solid surfaces with the aid of flagella. It has been hypothesized that swarmer cells overcome the increased viscous drag near surfaces by developing higher flagellar thrust and by promoting surface wetness with the aid of a flagellar switch. The switch enables reversals between clockwise (CW) and counterclockwise (CCW) directions of rotation of the flagellar motor. Here, we measured the behavior of flagellar motors in swarmer cells. Results indicated that although the torque was similar to that in planktonic cells, the tendency to rotate CCW was higher in swarmer cells. This suggested that swarmers likely have a smaller pool of phosphorylated CheY. Results further indicated that the upregulation of the flagellin gene was not critical for flagellar thrust or swarming. Consistent with earlier reports, moisture added to the swarm surface restored swarming in a CCW-only mutant, but not in a FliG mutant that rotated motors CW-only (FliGCW). Fluorescence assays revealed that FliGCW cells grown on agar surfaces carried fewer flagella than planktonic FliGCW cells. The surface-dependent reduction in flagella correlated with a reduction in the number of putative flagellar preassemblies. These results hint toward a possibility that the conformational dynamics of switch proteins play a role in the proper assembly of flagellar complexes and flagellar export, thereby aiding bacterial swarming.
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影响因子：
9.8
作者：
Fukumura T;Makino F;Dietsche T;Kinoshita M;Kato T;Wagner S;Namba K;Imada K;Minamino T
通讯作者：
Minamino T
DOI：
10.1073/pnas.91.18.8631
发表时间：
1994-08-30
影响因子：
11.1
作者：
HARSHEY, RM;MATSUYAMA, T
通讯作者：
MATSUYAMA, T
影响因子：
1.2
作者：
Ford, Katie M.;Chawla, Ravi;Lele, Pushkar P.
通讯作者：
Lele, Pushkar P.
影响因子：
6.4
作者：
Kim W;Surette MG
通讯作者：
Surette MG
影响因子：
56.9
作者：
Blair, Kris M.;Turner, Linda;Kearns, Daniel B.
通讯作者：
Kearns, Daniel B.