On the Move

Travelling 5 millimetres in one minute sounds slow. But if you’re a human sperm, it’s pretty speedy. While mature sperm can whizz about, immature sperm are immobile. So how do they move through the tubes in the testicles (seminiferous tubules) where they’re made? Researchers investigated in mice using live cell imaging of the tubules to measure the flow of fluid through them. They found the flow matched the contractions of muscle-like cells in the tubule walls, pictured here (red) in a 3D reconstruction of mouse testes compiled using fluorescence confocal microscopy. Contractions were detected by fluorescently tagging and imaging calcium levels in these cells, which rise when they contract. It’s these coordinated contractions that propel the immature sperm through the tubules. This builds a clearer picture of how immobile sperm get moving.

Written by Lux Fatimathas

Lux Fatimathas

Writer

Having pursued science through a career in research, communications and publishing, she is currently a writer and editor for a healthcare marketing agency and also juggles freelance science writing.

• Image from work by David Fleck and Lina Kenzler, and colleagues
• Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in eLife, January 2021