Proc. Natl Acad. Sci. USA 105, 12497–12502 (2008)

Credit: D. L. Burdette et al./PNAS

The bacterial pathogen Vibrio parahaemolyticus has an unusual way of killing cells, researchers report.

V. parahaemolyticus causes severe diarrhoea and can be life threatening in people with weakened immune systems. Previous work had suggested that the bacteria kill cells by injecting them with proteins that trigger a kind of cellular suicide called apoptosis. But Kim Orth and her colleagues at the University of Texas Southwestern Medical Center have found that dying cells do not express enzymes characteristic of this.

Instead, the cells were inflamed. They became more rounded (progression pictured left to right for two samples), began to degrade their own contents and started to leak. These events occurred in only a few hours, and together provide a new means by which a pathogen that works from outside a cell can kill its target.