The tail that lets a bacterium swim can also split it open

In Bacillus subtilis, finishing the flagellar hook switches on enzymes that break down part of the bacterium's own protective wall. PBP1 normally patches the damage; when researchers removed it, flagellum construction lined up with cells rupturing and dying. That lethal connection is experimental evidence in one model bacterium; whether related pathogens share an exploitable weakness remains a question for future work.