Picou Theodore J, Luo Haibei, Polackwich Robert J, Gabilondo Beatriz B, McAllister Ryan G, Gagnon David A, Powers Thomas R, Elmendorf Heidi G, Urbach Jeffrey S
Department of Biology, Georgetown University, Washington, DC, USA.
Department of Physics and Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, DC, USA.
PNAS Nexus. 2024 Nov 29;3(12):pgae545. doi: 10.1093/pnasnexus/pgae545. eCollection 2024 Dec.
The ability of microbes to attach to biological and inert substrates is a necessary prerequisite for colonization of new habitats. In contrast to well-characterized mechanisms that rely on specific or nonspecific chemical interactions between microbe and substrate, we describe here an effective hydrodynamic mechanism of attachment that relies on fluid flow generated by the microbe. The microbe , a flagellated protozoan parasite, naturally attaches to the microvilliated surface of the small intestine but is also capable of attaching indiscriminately to a wide range of natural and artificial substrates. By tracking fluorescent quantum dots, we demonstrate a persistent flow between the parasite and substrate generated by a pair of flagella. Using both experimental measures and computational modeling, we show that the negative pressure generated by this fluid flow is sufficient to generate the previously measured force of attachment. We further show that this dynamically generated negative pressure allows to attach to both solid and porous surfaces, thereby meeting the real-world demands of attachment to the microvilliated surface of intestinal cells. These findings provide experimental support for a hydrodynamic model of attachment that may be shared by other ciliated and flagellated microbes.
微生物附着于生物和惰性底物的能力是其在新栖息地定殖的必要前提条件。与依赖微生物与底物之间特定或非特定化学相互作用的已充分表征的机制不同，我们在此描述一种有效的流体动力学附着机制，该机制依赖于微生物产生的流体流动。这种微生物是一种有鞭毛的原生动物寄生虫，它自然附着于小肠的微绒毛表面，但也能够无差别地附着于多种天然和人工底物。通过追踪荧光量子点，我们证明了由一对鞭毛产生的寄生虫与底物之间的持续流动。通过实验测量和计算建模，我们表明这种流体流动产生的负压足以产生先前测量的附着力。我们进一步表明，这种动态产生的负压使寄生虫能够附着于固体和多孔表面，从而满足其附着于肠道细胞微绒毛表面的实际需求。这些发现为一种可能被其他有纤毛和有鞭毛的微生物共享的流体动力学附着模型提供了实验支持。
