Rickettsia (magenta) are bacteria that cause deadly diseases, including spotted fevers and typhus. They are some of the only bacteria known to invade the nuclei (black ovals) of the human cells they infect. Normally, cells protect their DNA by strictly regulating what enters nuclei—how do these bacteria get in?

In this image, researchers saw bacteria entering human cell nuclei via large protrusions in the surrounding membrane (cyan). By studying this mechanism, they hope to devise better strategies to treat this dangerous pathogen.