Weaver Abigail A, Bolster Diogo, Madukoma Chinedu S, Mattingly Anne E, Morales-Soto Nydia, Shrout Joshua D
Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN.
Department of Biological Sciences, University of Notre Dame, Notre Dame, IN.
Appl Environ Microbiol. 2021 Apr 15;87(8). doi: 10.1128/AEM.03067-20. Epub 2021 Feb 12.
There are many hydrated surface niches that are neither static nor continuously flowing that are colonized by microbes such as bacteria. Such periodic hydrodynamic regimes are distinct from aquatic systems where microbial dissemination is reasonably predicted by assuming continuous flow or static systems where motile microbes largely control their own fate. Here we show how non-motile bacteria exhibit rapid, dispersive bursts of movement over surfaces using transient confluent hydration from the environment, which we term "surface hydrodispersion" where cells traverse thousands of cell lengths within minutes. The fraction of the population disseminated by surface hydrodispersion is small-on order of 1 cell per million. Thus, surface hydrodispersion can promote isolated distribution of single cells, which is unlike other characterized active and passive surface motilities. We describe this translocation using a continuous time random walk modeling approach and find in computational simulations that transient fluid accumulation, dilution, and gravitational pull are the contributing factors. Surface hydrodispersion, consistent with advection, is unlike simple colony expansion as it dramatically alters spatial relationships, shown here with , which becomes increasingly virulent when isolated from Surface hydrodispersion of non-motile bacteria exploiting transient fluid availability and gravity is a mechanism that can result in sporadic and sudden shifts in microbial community behavior. To better understand how this movement can impact biogeography on the millimeter scale, this work describes a system for study of primary factors behind this movement as well as a stochastic model describing this dispersal. Understanding the dynamics within microbiome communities is a challenge. Knowledge of phylogeny and spatial arrangement has led to increased understanding of numerous polymicrobial communities yet, these snapshots do not convey the dynamics of populations over time. The actual biogeography of any microbiome controls the potential interactions, governing any possible antagonistic or synergistic behavior. Accordingly, a shift in biogeography can enable new behavior. Little is known about the movement mechanisms of "non-motile" microbes. Here we characterize a universal means of movement we term hydrodispersion where non-motile bacteria are transported thousands of cell lengths in minutes. We show that only a small fraction of the population is translocated by hydrodispersion and describe this movement further using a random-walk mathematical model approach We demonstrate the importance of hydrodispersion by showing that can separate from a coculture inoculation with thus permitting transition to a more virulent state.
存在许多既非静态也非持续流动的水合表面生态位，细菌等微生物会在这些生态位中定殖。这种周期性的流体动力学状态不同于水生系统，在水生系统中，通过假设连续流动可以合理预测微生物的传播；也不同于静态系统，在静态系统中，能动的微生物很大程度上控制着它们自己的命运。在这里，我们展示了非能动细菌如何利用来自环境的瞬态汇合水合作用在表面上呈现快速、分散的移动爆发，我们将其称为“表面水扩散”，在这种情况下，细胞在几分钟内就能穿越数千个细胞长度。通过表面水扩散传播的群体比例很小——大约每百万个细胞中有1个细胞。因此，表面水扩散可以促进单细胞的孤立分布，这与其他已表征的主动和被动表面运动不同。我们使用连续时间随机游走建模方法来描述这种易位，并在计算模拟中发现瞬态流体积累、稀释和重力是促成因素。与平流一致，表面水扩散不同于简单的菌落扩展，因为它会显著改变空间关系，在此处通过 展示，当从 分离时，其毒性会越来越强。非能动细菌利用瞬态流体可用性和重力进行的表面水扩散是一种机制，可导致微生物群落行为的零星和突然转变。为了更好地理解这种移动如何在毫米尺度上影响生物地理学，这项工作描述了一个用于研究这种移动背后主要因素的系统以及一个描述这种扩散的随机模型。理解微生物群落中的动态是一项挑战。系统发育和空间排列的知识使人们对众多多微生物群落有了更多了解，然而，这些快照并不能传达种群随时间的动态。任何微生物群落的实际生物地理学控制着潜在的相互作用，支配着任何可能的拮抗或协同行为。因此，生物地理学的转变可以促成新的行为。人们对“非能动”微生物的移动机制知之甚少。在这里，我们描述了一种我们称为水扩散的通用移动方式，在这种方式下，非能动细菌在几分钟内就能被运输数千个细胞长度。我们表明，只有一小部分群体通过水扩散易位，并使用随机游走数学模型方法进一步描述这种移动。我们通过表明 可以从与 的共培养接种中分离出来，从而允许转变为更具毒性的状态，证明了水扩散的重要性。
