When Sperm Meets Egg, Zinc Sparks Fly

Billions of tiny zinc particles explode from the surface of mammalian eggs when a sperm cell touches down

Watching zinc sparks fly as egg meets sperm

When sperm meets egg, sparks ensue, according to new research published in Nature Chemistry. The coupling of those two cells releases millions of zinc particles in several waves that, when viewed with fluorescence, pulse like a firefly. All mammalian eggs exhibit this phenomenon, which the researchers captured on camera for the first time, Discovery News writes

While scientists already knew that fertilization triggered a flood of zinc, they did not understand how the process worked and they had never seen it before. The team visualized the zinc explosion in a living cell by using a new method that tags individual zinc particles with fluorescence. The researchers found that each egg cell contains about 8,000 tiny containers for storing zinc, Discovery continues, and each of those compartments can hold up to one million zinc atoms. About 10 billion of the egg's 60 billion total zinc atoms are released upon fertilization. 

Scientists know that zinc plays a vital role in healthy embryo development, and the authors of this new study think the zinc fireworks are also a crucial step differentiating egg from embryo. As such, Discovery reports, zinc could serve as a marker of the health of a fertilized egg, for example, if the best eggs are those that release the most zinc. As such, Discovery writes, the finding might lead to ways to improve the chances of in vitro fertilization working, since doctors could choose those eggs that are healthiest and most likely to survive. 

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