As spring arrives, flowers seem to bloom everywhere – even under the microscopes at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany. But the ‘flowers’ in this picture actually help an animal, not a plant, to pass on its genes. The image, which has been false-coloured for artistic effect, shows a slice through the tails of mouse sperm. Each ‘flower’ is the tail that a sperm cell wags to swim. Inside it, you can glimpse the secret behind sperm’s typical swimming technique: two tubes called microtubules, surrounded by a ring of nine other microtubule pairs. With the help of specialist ‘motor’ proteins, these microtubules make the sperm tail beat, enabling the sperm to swim.
The image was taken using an electron microscope, and shows sperm tails from a healthy mouse, magnified 46 000 times. While comparing sperm formation in healthy and genetically altered mice, Charlotta Funaya, a research technician at EMBL, was struck by the image’s beauty. “This particular image didn’t really serve a scientific purpose,” she says: “I took it because it looked pretty.”
Image credit: EMBL/C.Funaya & P. Riedinger