Images reveal secrets of zinc sparks

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When egg meets sperm in mammals, zinc sparks fly. These sparks are created when billions of zinc atoms shoot from thousands of small pouches nestled just beneath the surface of a mouse egg cell, researchers from Northwestern University and Argonne National Laboratory report December 15 in Nature Chemistry. The team used detailed imaging and mapping techniques to capture the outburst and origin of the sparks, which are needed to stimulate the transition from egg to embryo. The research could help scientists figure out how changes in zinc levels control what’s happening in cells and may have implications for identifying the best eggs for in vitro fertilization. 

ZINC SHOOTERS  As egg meet sperm, zinc sparks fly. This movie shows the moment of fertilization, revealing hot spots of fluorescence at the cell surface. These spots are pouches filled with zinc atoms that erupt to create zinc sparks dancing about the newly minted embryo.
Credit: Northwestern University