Bacteria have a number of tools to fend off of foes or attack competitors, but now a new method can be added to the list: a spring-loaded dagger.
Research published in Nature by scientists at the Harvard Medical School and the California Institute of Technology investigated the structure of a mechanism used by the bacteria vibrio cholera to kill both competing bacteria and human cells, called the Type VI Secretary System (T6SS).

Scanning electron microscope image of Vibrio cholerae bacteria, which infect the digestive system
It’s known that T6SS can deliver toxic proteins into nearby cells, but until now the exact mechanism was not known; now it appears T6SS could be using a poison tipped dagger to deliver this killing blow.
“People aren’t surprised that animals have really interesting ways to hurt each other – snakes have venom, bears have claws,” says Grant Jensen, professor of biology at Caltech and co-leader of the study. “But they might be surprised that a single cell within one of those animals’ bodies is still 100 times larger than the bacterial cells we’re talking about, and yet the bacterial cells contain weapons that are so sophisticated. That’s the marvel.” Continue reading →
Tags: biology, cholera, dagger, electron cryomicrograph, electron microscopy, fluorescent, GFP, Harvard, microbiology, nano-dagger, Nature, science, T6SS, toxin, Type VI Secretary System, vibrio cholera