Mammalian oocytes undergo major changes in zinc content and localization to be fertilized, the most striking being the rapid exocytosis of over 10 billion zinc ions in what are known as zinc sparks. Here, we report that fertilization of amphibian Xenopus laevis eggs also initiates a zinc spark that progresses across the cell surface in coordination with dynamic calcium waves. This zinc exocytosis is accompanied by a newly recognized loss of intracellular manganese. Synchrotron-based X-ray fluorescence and analytical electron microscopy reveal that zinc and manganese are sequestered in a system of cortical granules that are abundant at the animal pole. Through electron–nuclear double-resonance studies, we rule out Mn²⁺ complexation with phosphate or nitrogenous ligands in intact eggs, but the data are consistent with a carboxylate coordination environment. Our observations suggest that zinc and manganese fluxes are a conserved feature of fertilization in vertebrates and that they function as part of a physiological block to polyspermy.

哺乳动物卵母细胞的锌含量和受精定位发生重大变化，最引人注目的是在所谓的锌火花中快速胞吐超过 100 亿个锌离子。在这里，我们报告两栖动物非洲爪蟾卵的受精也会引发锌火花，该锌火花与动态钙波协调在细胞表面前进。这种锌胞吐作用伴随着新发现的细胞内锰丢失。基于同步加速器的 X 射线荧光和分析电子显微镜显示，锌和锰被隔离在动物极丰富的皮质颗粒系统中。通过电子-核双共振研究，我们排除了 Mn ²⁺与完整鸡蛋中的磷酸盐或含氮配体络合，但数据与羧酸盐配位环境一致。我们的观察表明，锌和锰通量是脊椎动物受精的一个保守特征，并且它们作为多精子生理障碍的一部分发挥作用。