Department of Bioscience and Informatics, Keio University, Yokohama 223-8522, Japan.
Int J Mol Sci. 2021 Aug 24;22(17):9104. doi: 10.3390/ijms22179104.
In echinoderms, sperm swims in random circles and turns in response to a chemoattractant. The chemoattractant evokes transient Ca influx in the sperm flagellum and induces turning behavior. Recently, the molecular mechanisms and biophysical properties of this sperm response have been clarified. Based on these experimental findings, in this study, we reconstructed a sperm model in silico to demonstrate an algorithm for sperm chemotaxis. We also focused on the importance of desensitizing the chemoattractant receptor in long-range chemotaxis because sperm approach distantly located eggs, and they must sense the chemoattractant concentration over a broad range. Using parameters of the sea urchin, simulations showed that a number of sperm could reach the egg from millimeter-order distances with desensitization, indicating that we could organize a functional sperm model, and that desensitization of the receptor is essential for sperm chemotaxis. Then, we compared the model with starfish sperm, which has a different desensitization scheme and analyzed the properties of the model against various disturbances. Our approach can be applied as a novel tool in chemotaxis research.
在棘皮动物中，精子随机游动并在趋化剂的刺激下转向。趋化剂在精子鞭毛中引发短暂的钙离子内流，并诱导转向行为。最近，这种精子反应的分子机制和生物物理特性已经得到阐明。基于这些实验发现，本研究在计算机中重建了一个精子模型，以演示精子趋化性的算法。我们还关注了在长距离趋化过程中使趋化剂受体脱敏的重要性，因为精子会接近远距离的卵子，它们必须在广泛的范围内感知趋化剂浓度。使用海胆的参数，模拟表明，在脱敏作用下，许多精子可以从毫米级的距离到达卵子，这表明我们可以组织一个功能性的精子模型，并且受体的脱敏对于精子趋化性是至关重要的。然后，我们将该模型与海星精子进行了比较，后者具有不同的脱敏方案，并针对各种干扰分析了模型的特性。我们的方法可以作为趋化性研究的一种新工具。
