Mechanical shear controls bacterial penetration in mucus
Mechanical shear controls bacterial penetration in mucus
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DOI：
10.1038/s41598-019-46085-z
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发表时间：
2019-07-04
影响因子：
4.6
通讯作者：
Aranson, Igor S.
中科院分区：
文献类型：
--
作者：
Figueroa-Morales, Nuris;Dominguez-Rubio, Leonardo;Aranson, Igor S.
粘液在高等生物中起着至关重要的作用，从帮助受精到保护女性生殖道。在这里，我们研究了粘液的各向异性组织如何影响细菌的运动。我们通过低温电子显微镜和细长示踪粒子成像证明，黏液的各向异性和异质性取决于机械应力的施加方式。在浅层黏液膜中，我们观察到细菌在没有u型转弯的情况下逆转了它们的游动方向。在向前移动的过程中，细菌在隧道中挖洞，持续几秒钟，使它们能够沿着相同的轨迹更快地游回来。我们通过鞭毛的荧光可视化阐明了方向逆转的物理机制：当细菌体突然被黏液结构阻止时，鞭毛束受到的压迫导致细菌另一侧的屈曲、解体和重组。我们的研究结果揭示了细菌在复杂粘弹性流体中的运动性，并为细菌传播疾病在粘液中的传播提供了线索。
Mucus plays crucial roles in higher organisms, from aiding fertilization to protecting the female reproductive tract. Here, we investigate how anisotropic organization of mucus affects bacterial motility. We demonstrate by cryo electron micrographs and elongated tracer particles imaging, that mucus anisotropy and heterogeneity depend on how mechanical stress is applied. In shallow mucus films, we observe bacteria reversing their swimming direction without U-turns. During the forward motion, bacteria burrowed tunnels that last for several seconds and enable them to swim back faster, following the same track. We elucidate the physical mechanism of direction reversal by fluorescent visualization of the flagella: when the bacterial body is suddenly stopped by the mucus structure, the compression on the flagellar bundle causes buckling, disassembly and reorganization on the other side of the bacterium. Our results shed light into motility of bacteria in complex visco-elastic fluids and can provide clues in the propagation of bacteria-born diseases in mucus.