Eggsplosion

One of life’s most delicate processes starts with an explosion. This mouse’s ovarian follicle prepares to launch an egg at high speed – the black circle here (~100 times smaller than a cannonball). Like a lot of dramatic biological events, ovulation is usually hidden from view, so scientists find innovative ways to examine its steps. Bathing this mouse follicle in nurturing chemicals under a microscope, scientists use fluorescent dyes to highlight its membrane (green) and the liquid inside (red). They find that first, the follicle expands, filling up with chemicals rushing in from its surroundings. Fit to burst, muscle cells on the outside squeeze the follicle, which ruptures at a thin part of its wall, propelling the egg on its way. Perhaps starting from a similar blast, the journey from human ovulation to fertilisation to pregnancy is still full of mystery, relying on experiments like these for clues.

Written by John Ankers

John Ankers

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A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

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• Video from work by Christopher Thomas and Tabea Lilian Marx, and colleagues
• Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
• Video originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Nature Cell Biology, October 2024