When individual cells die, it triggers a chemical chain reaction that leads to the breakdown of cell components and a build-up of molecular debris. The molecular mechanisms of this are reasonably well understood at a cellular level but we know much less about how death spreads throughout an organism at the end of its life.
In worms, the spread of death can be seen easily under a microscope as a wave of blue fluorescence travelling through the gut of the worm. The study, led by researchers funded by the Wellcome Trust and BBSRC, reveals that this fluorescence is caused by a cell death pathway called necrosis and its spread throughout the organism is dependent on calcium signalling.
Professor David Gems from the Institute of Health Ageing at UCL, who led the study, explains: "We've identified a chemical pathway of self-destruction that propagates cell death in worms, which we see as this glowing blue fluorescence travelling through the body." It's like a blue grim reaper, tracking death as it spreads throughout the organism until all life is extinguished.