Confinement discerns swarmers from planktonic bacteria.
Confinement discerns swarmers from planktonic bacteria.
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DOI：
10.7554/elife.64176
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发表时间：
2021-04-22
期刊：
影响因子：
7.7
通讯作者：
Tang JX
中科院分区：
文献类型：
--
作者：
Chen W;Mani N;Karani H;Li H;Mani S;Tang JX
由鞭毛提供动力，许多细菌物种在固体表面上表现出集体运动，通常称为群集。作为活性物质的自然例子，群集也是与毒力、趋化性和宿主致病性相关的基本生物表型。物理变化，如细胞伸长和超鞭毛已被证明伴随着群集表型。然而，较少研究的是群集细胞与其对应的细胞密度相当的群集细胞之间的集体运动的对比。在这里，我们表明，在圆形微孔中限制细菌运动可以区分细菌群集和集体游泳。在软琼脂平板上，当限制在特定尺寸范围的圆形微孔中时，处于群集和群集状态的新型细菌菌株肠杆菌属SM 3表现出不同的运动模式。当限制直径为40 ~ 90 μm时，群集型SM 3在微孔中形成单涡旋运动模式，而非群集型SM 3形成多涡旋运动模式。在其他几种革兰氏阴性菌中也观察到类似的差异行为。我们还观察到稀释后群集细菌的“漂流行为”。我们推测漂流行为可能是造成运动模式差异的原因。我们能够通过数值模拟来预测这些实验特征，其中群集细胞被建模为具有更强的细胞-细胞对齐相互作用。我们的实验设计使用PDMS微芯片磁盘阵列使我们能够观察细菌群集在小鼠肠道表面，提出了一种新的方法来表征细菌群集在复杂的环境下，如在多微生物的小生境，并在体内群集探索。
Powered by flagella, many bacterial species exhibit collective motion on a solid surface commonly known as swarming. As a natural example of active matter, swarming is also an essential biological phenotype associated with virulence, chemotaxis, and host pathogenesis. Physical changes like cell elongation and hyper-flagellation have been shown to accompany the swarming phenotype. Less studied, however, are the contrasts of collective motion between the swarming cells and their counterpart planktonic cells of comparable cell density. Here, we show that confining bacterial movement in circular microwells allows distinguishing bacterial swarming from collective swimming. On a soft agar plate, a novel bacterial strain Enterobacter sp. SM3 in swarming and planktonic states exhibited different motion patterns when confined to circular microwells of a specific range of sizes. When the confinement diameter was between 40 μm and 90 μm, swarming SM3 formed a single-swirl motion pattern in the microwells whereas planktonic SM3 formed multiple swirls. Similar differential behavior is observed across several other species of gram-negative bacteria. We also observed ‘rafting behavior’ of swarming bacteria upon dilution. We hypothesize that the rafting behavior might account for the motion pattern difference. We were able to predict these experimental features via numerical simulations where swarming cells are modeled with stronger cell–cell alignment interaction. Our experimental design using PDMS microchip disk arrays enabled us to observe bacterial swarming on murine intestinal surface, suggesting a new method for characterizing bacterial swarming under complex environments, such as in polymicrobial niches, and for in vivo swarming exploration.