Quick Soniya R, Bains Jason, Gerdt Catherine, Walker Bryan, Goldstone Eleanor B, Jakuszeit Theresa, Baggaley Andrew W, Croze Ottavio A, Gerdt Joseph P
Department of Chemistry, Indiana University, Bloomington, IN 47405, USA.
School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom.
bioRxiv. 2025 May 2:2025.05.01.651543. doi: 10.1101/2025.05.01.651543.
Regulated motility is vital for many cells-both for unicellular microbes and for cells within multicellular bodies. Different conditions require different rates and directions of movement. For the microbial predator , its motility is likely essential for predation. This organism has been shown to prey on diverse organisms, including the schistosome parasites that co-reside with it in snails. is also an evolutionary model for the unicellular ancestor of animals. This phylogenic placement makes 's motility an attractive target for understanding the evolution of motility in animal cells. Until now, little was known of how regulates it rate and direction of motility. Here we found that it exhibits chemokinesis (increased movement in response to chemical factors) in response to proteins released from prey cells. Chemokinesis also occurs in response to pure proteins-including bovine serum albumin. We found that this chemokinesis behavior is dependent on cell density, which suggests that the regulated motility is a cooperative behavior (possibly to improve cooperative feeding). We developed a mathematical model of motility and found that chemokinesis alone does not benefit predation. However, when coupled with chemotaxis (directional motility along a chemical gradient toward prey), chemokinesis may improve predation. Finally, we quantitatively analyzed 's previously reported chemotaxis behavior. These findings lay a foundation for characterizing the mechanisms of regulated motility in a predator of a human pathogen and a model for the ancestor of animals.
受调控的运动能力对许多细胞至关重要——无论是单细胞微生物还是多细胞生物体内的细胞。不同的条件需要不同的运动速率和方向。对于这种微生物捕食者而言，其运动能力可能对捕食至关重要。已证明这种生物会捕食多种生物，包括与其共同生活在蜗牛体内的血吸虫寄生虫。它也是动物单细胞祖先的进化模型。这种系统发育定位使得它的运动能力成为理解动物细胞运动能力进化的一个有吸引力的研究对象。到目前为止，人们对它如何调节运动速率和方向知之甚少。在这里，我们发现它会对猎物细胞释放的蛋白质产生趋化性运动（对化学因子作出反应而增加运动）。趋化性运动也会对纯蛋白质（包括牛血清白蛋白）作出反应。我们发现这种趋化性运动行为依赖于细胞密度，这表明受调控的运动是一种合作行为（可能是为了改善合作进食）。我们建立了一个关于它运动能力的数学模型，发现仅趋化性运动对捕食没有益处。然而，当与趋化作用（沿着化学梯度向猎物进行定向运动）相结合时，趋化性运动可能会改善捕食。最后，我们对之前报道的它的趋化作用行为进行了定量分析。这些发现为阐明人类病原体捕食者以及动物祖先模型中受调控运动机制奠定了基础。
