Researchers have discovered how bacteria break through spaces barely larger than themselves, by wrapping their flagella around their bodies and moving forward. Using a microfluidic device that mimics insect gut channels, the team revealed a remarkable "flagellar wrapping" motion that lets symbiotic bacteria pass through 1-micrometer-wide tunnels. Genetic manipulation and mathematical calculation showed that the flexibility of a tiny joint in the flagellum, called the hook, is crucial for this screw-like movement and even determines whether the bacteria can successfully infect their insect hosts.
